Infrared ray detector and infrared ray image detector using infrared ray detector

The present invention relates to an infrared image sensor in which a plurality of infrared detectors are arranged, and in particular, a thermal infrared image pickup device that senses infrared rays as heat.

[0002] Conventionally, in a thermal infrared imaging device that senses infrared rays as heat, a plurality of thermal infrared detectors are arranged two-dimensionally. As an example of the thermal infrared imaging device, for example, there is a thermal infrared imaging device using a Si pn junction diode in the detection unit (see Japanese Patent Application Laid-Open No. 2001-281051). This thermal infrared imaging device utilizes infrared rays emitted from an object in which the height of the diffusion potential barrier and the number of carriers change according to the temperature change of the pn junction diode. Specifically, an infrared absorber whose temperature changes by irradiation with infrared rays is provided on the surface of each pixel of the thermal infrared image pickup device, and the temperature change is guided to, for example, a pn junction diode to form a pn junction band structure. Is changed. By reading this change, for example, as a voltage change due to constant current operation, it is possible to observe the intensity of the irradiated infrared rays and detect the measurement object and the surface temperature.

[0003] In the thermal infrared imaging apparatus disclosed in Japanese Patent Application Laid-Open No. 2001-281051, a plurality of microcavity regions are provided in a matrix on the surface of a substrate, and support legs are provided inside each of the microcavity regions. The detection unit of each pixel is supported in a hollow state through the structure. By supporting the detection unit in a hollow state, the detection unit is supported in a thermally separated state. The detection unit includes an infrared absorption layer that absorbs incident infrared rays and converts them into heat, and a thermoelectric exchange unit that converts temperature changes due to the infrared absorption layer into electrical signals. A horizontal address line and a vertical signal line are connected to the thermoelectric exchange section of each pixel. The horizontal address lines and vertical signal lines are arranged in a grid pattern that is orthogonal to each other. When reading the signal, a pulse signal is applied to the horizontal address line. Since the detection unit is supported in a hollow state in the minute cavity region on the surface of the substrate via the support legs, the heat generated by the detection unit is less likely to be released to the outside, and a heat insulating structure is formed.

[0004] In order to increase the sensitivity of this conventional thermal infrared imaging device, it is necessary to set the bias current value so that the S / N ratio becomes large, and it is better to increase the heat confinement of infrared rays. It becomes possible to greatly detect the temperature change with respect to. As a result, a self-overheating phenomenon occurs in which the temperature of the entire detection unit rises as shown in FIG. 27. This self-heating effect occurs when a bias pulse is applied to the detection unit, but since the temperature of the detection unit drops when no pulse is applied (blanking time), the destruction phenomenon of the detection unit due to thermal runaway does not occur.

[0005] [Problems to be Solved by the Invention] Recently, an attempt has been made to use a thermal infrared imaging device for nighttime forward monitoring of a passenger car. The purpose is to detect information that cannot be obtained with a normal visible camera. For in-vehicle purposes, a frame rate (FR) that is many times higher than that of current thermal infrared cameras is required. However, in the conventional thermal infrared imaging device, when the frame rate increases, the heat increase in the detection unit generated by the self-heating phenomenon cannot be sufficiently reduced due to the blanking time, and as a result, the detection unit as shown in FIG. 28 The heat rise in the above is superimposed and causes a heat destruction phenomenon.

[0006] In order to prevent the above-mentioned thermal destruction phenomenon, it is necessary to reduce the thermal time constant by reducing the thermal resistance of the support legs and at the same time reducing the heat capacity of the detection unit. However, reducing the thermal time constant also reduces the sensitivity of the thermal infrared imaging device.

[0007] In view of the above-mentioned problems of the conventional thermal infrared imaging apparatus, the present invention is a thermal type that does not reduce the sensitivity even if the frame rate is increased and does not cause thermal destruction due to the self-heating phenomenon. It is to provide an infrared image pickup apparatus.

[Means for Solving the Problems] In order to achieve the above object, the present invention comprises (a) a substrate in which a plurality of microcavity regions are arranged on the surface, and (b) a substrate in which the microcavity regions are arranged. At the timing of reading the infrared rays detected by the detection unit as an electric signal, which are provided between the plurality of detection units (c) and the plurality of detection units, respectively, to detect the infrared rays supported in the thermally separated state. The infrared imaging device is provided with a mechanical switching element that maintains the thermal separation state, short-circuits the thermal separation state during blanking other than timing, and dissipates the heat accumulated in the detection unit to the substrate. It is a summary. Here, "supporting in a state of being thermally separated from the substrate" means supporting in a state where the flow of heat to the substrate is suppressed to a size that does not cause a problem in the operation of the infrared imaging apparatus. Specifically, by increasing the thermal resistance of the support legs that support the detection unit in a hollow state with respect to the substrate, heat conduction can be suppressed and heat flow to the substrate can be suppressed.

[0009] According to the infrared imaging apparatus according to the feature of the present invention, by using the mechanical switching element, it is possible to dissipate the temperature rise of the detection unit due to self-heating to the substrate and reset it. Therefore, it is possible to further increase the frame rate of the infrared image pickup apparatus, and it is possible to obtain a highly sensitive and high-speed response. Further, even if the frame rate is increased, the heat dissipation at the detection unit generated by the self-heating phenomenon is good, so that the heat destruction phenomenon can be avoided. As a result, it is possible to provide a high-speed, high-sensitivity thermal infrared imaging device having a frame rate that is about 5 to 10 times higher than that of a conventional thermal infrared camera.

[0010] The mechanical switching element used in the infrared imaging apparatus according to the feature of the present invention is, for example, electrically connected to the wiring of a movable portion arranged on the surface of the substrate, and the fixed end is fixed to the substrate, and the fixed end is fixed to the substrate. The conductive movable part of the cantilever structure in which the free end extends from the end side to the upper part of the detection part, and the control electrode wiring arranged on the surface of the substrate are electrically connected to the fixed end on the surface of the substrate. A control electrode arranged between the free ends may be provided. In this way, by adjusting the voltage supplied to the movable part via the movable part wiring and the voltage supplied to the control electrode via the control electrode wiring, the free end is brought into contact with the detection part by electrostatic attraction. Alternatively, it is possible to bring them close to each other and dissipate the temperature rise of the detection unit due to self-heating to the substrate to reset it.

[0011] Alternatively, the mechanical switching element is electrically connected to the movable portion wiring arranged on the surface of the substrate, and the fixed end is fixed to the substrate, and the free end is provided from the fixed end side to the upper part of the detection portion. A conductive movable portion having an extending cantilever structure and a control electrode electrically connected to the control electrode wiring arranged on the surface of the substrate and arranged on the surface of the detection portion may be provided. .. Also in this case, by adjusting the voltage supplied to the movable part via the movable part wiring and the voltage supplied to the control electrode via the control electrode wiring, the free end is brought into contact with the detection part by electrostatic attraction. Alternatively, it is possible to bring them close to each other and dissipate the temperature rise of the detection unit due to self-heating to the substrate to reset it. By arranging the control electrode inside the detection unit, the effective area of the control electrode that functions as a mechanical switching element and the part facing it becomes large, and as a result, high-efficiency heat dissipation switch operation is possible at low voltage. It becomes.

[0012] Further, the detection unit is arranged above the conductive movable portion and is arranged below the infrared absorbing layer that absorbs infrared rays, and is arranged below the conductive movable portion and converts the heat generated in the infrared absorbing layer into an electric signal. The thermoelectric conversion unit may be provided with a support unit that thermally connects the infrared absorbing layer and the thermoelectric conversion unit and mechanically supports the infrared absorbing layer with respect to the thermoelectric conversion unit. That is, a conductive movable part is located between the infrared absorption layer and the thermoelectric conversion part, and the infrared absorption layer is hollow above the thermoelectric conversion part by using a support part that is thermally connected to the thermoelectric conversion part. Since it is fixed, the aperture ratio of infrared absorption is increased, and more sensitive detection becomes possible.

BEST MODE FOR CARRYING OUT THE INVENTION Next, first to fifth embodiments of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the plane dimension, the ratio of the thickness of each layer, etc. are different from the actual ones. Therefore, the specific thickness and dimensions should be determined in consideration of the following explanation. It goes without saying that the drawings also include parts having different dimensional relationships and ratios.

(First Embodiment) As shown in FIG. 1, the infrared imaging apparatus according to the first embodiment of the present invention has a plurality of vertical signal lines B._j-1, B_j, B_{j + 1}, ... and these multiple vertical signal lines B_j-1, B_j, B_{j + 1}Multiple horizontal address lines W extending in the vertical direction with respect to ..._i-1, W_i, W_{i + 1}Detection unit X that constitutes each pixel inside the matrix composed of ..._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}... is arranged in two dimensions. In addition, the vertical signal line B_j-1, B_j, B_{j + 1}In parallel with, ..., moving part wiring G_j-2, G_j-1, G_j, ... is running. Also, the horizontal address line W_i-1, W_i, W_{i + 1}In parallel with, ..., control electrode wiring C_i-1, C_i, C_{i + 1}, ... is running.

FIG. 2A is a cross-sectional view taken along the AA direction of FIG. 1, and FIG. 2B is a cross-sectional view taken along the BB direction of FIG._{i, j}The substrate (1,2,4) on which is placed on the surface and this microcavity region Q_{i, j}Detector X supported by the substrate (1,2,4) in a thermally separated state._{i, j}It shows a structure consisting of. The substrate (1,2,4) is based on the SOI structure, and the support substrate (single crystal Si) 1 and the embedded oxide film (SiO) above the support substrate (single crystal Si) 1 are used.₂It is composed of a film) 2 and an element-separated oxide film 4 above the embedded oxide film 2. The device-separated oxide film 4 replaces the single crystal Si layer (SOI film) 3 constituting the SOI structure (see FIG. 7), and the single crystal Si layer 3 may remain in a part thereof. .. As shown in Fig. 2, the detector X_{i, j}, Microcavity area Q_{i, j}By storing it in a hollow state inside the detector X_{i, j}Can be thermally separated from the substrate (1,2,4). As shown in FIGS. 1 and 2 (a), the detector X that constitutes each pixel_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}... Is supported in a hollow state by the first support leg 21 and the second support leg 22 with respect to the substrate (1,2,4). In order to "support in a thermally separated state", the thermal resistance of the first support leg 21 and the second support leg 22 is increased, heat conduction is suppressed, and the heat flow to the substrate (1,2,4) is increased. It is suppressing. Microcavity area Q_{i, j}Is configured in an inverted pyramid shape at the bottom of a recess in which a part of the substrate (1,2,4) is selectively removed.

[0016] Detection unit X shown in FIG._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}As shown in FIG. 2, there are an infrared absorption layer 42 that absorbs incident infrared rays and converts them into heat, and a thermoelectric conversion unit 41 that converts temperature changes due to heat generated in the infrared absorption layer 42 into electrical signals. Includes. The thermoelectric conversion unit 41 has a structure in which a pn junction diode selectively doped with impurities is integrated on the surface of a single crystal Si layer. The bottom surface and the side surface of the single crystal Si layer 41 are covered with the embedded oxide film 2 and the element separation oxide film 4, respectively. Instead of pn junction diode, doped polysilicon, vanadium oxide (VO)₂), Titanium (Ti), amorphous silicon, and other bolometers can be used. An oxide film as a first interlayer insulating film 33a and a second interlayer insulating film 33b is arranged on the thermoelectric conversion unit 41 composed of the single crystal Si layer 41. Nitriding film (Si) is placed on the upper part of the oxide films 33a and 33b.₃N₄Membrane) 34 is arranged. The infrared absorption layer 42 is composed of a composite film composed of the oxide films 33a and 33b and the nitride film 34 on the upper part. The infrared absorption layer 42 is arranged in substantially the same shape as the thermoelectric conversion unit 41. The total thickness of the oxide films 33a and 33b can be selected to be, for example, about 1.5 μm, and the thickness of the nitride film 34 can be selected to be about 0.5 μm.

As shown in FIGS. 1 and 2 (a), the first support leg 21 and the second support leg 22 are the detection unit X._{i, j}Is mechanically supported by the support substrate 1, the embedded oxide film 2 on the upper part of the support substrate 1, and the element separation oxide film 4. Then, inside the first support leg 21, a thermoelectric conversion unit 41 is installed as a vertical signal line B._jThe thermoelectric conversion unit 41 is connected to the horizontal address line W inside the first detection unit wiring 51 and the second support leg 22 to be connected to._iThe second detector wiring 52 connected to is embedded. The first detection unit wiring 51 and the second detection unit wiring 52 are high melting point metals such as tungsten (W), titanium (Ti), cobalt (Co), and molybdenum (Mo), and these silicide (WSi).₂, TiSi₂, CoSi₂, MoSi₂) Etc., or may be composed of polysides using these silicides. The signal generated in the thermoelectric conversion unit 41 is guided to the processing circuit by the first detection unit wiring 51 and the second detection unit wiring 52.

Further, as shown in FIGS. 1 and 2 (b), each pixel is provided with a control electrode 37. The control electrode 37 of each pixel is connected to the control electrode wiring C via the control electrode auxiliary wiring 53._i-1, C_i, C_{i + 1}Connected to, ..., control electrode wiring C_i-1, C_i, C_{i + 1}A voltage is applied via ,. For example, as shown in FIG. 1, the control electrode 37 and the control electrode auxiliary wiring 53 are connected to the control electrode wiring C._i-1, C_i, C_{i + 1}, ... The same metal wiring layer (wiring level) above the metal wiring layer (wiring level), and each control electrode wiring C corresponding to the control electrode 37 via the via hole 56._i-1, C_i, C_{i + 1}, ... can be electrically connected.

As shown in FIGS. 1 and 2 (b), the conductive movable portion M of the cantilever structure faces the control electrode 37 of each pixel._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}, ... is provided, and the conductive movable part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}, ... is the moving part wiring G_j-2, G_j-1, G_j,·····It is connected to the. Conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}The fixed ends are fixed to the surface of the laminated structure consisting of the embedded oxide film 2 on the upper part of the support substrate 1, the element separation oxide film 4, the oxide films 33a and 33b, and the nitride film 34, respectively. Detection unit X from the end side_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}The structure is such that the free end extends to the upper part. Control electrode 37, conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}A mechanical switching element is configured by the above. This conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Metallic materials (conductive materials) such as aluminum (Al), copper (Cu), titanium (Ti), titanium nitride (TiN), and tungsten (W) are suitable for ...

FIG. 2 shows the horizontal address line W._iRow selection pulse V_iDetector X in the state where_{i, j}Indicates the selected state of. Row selection pulse V_iIn the blanking state immediately before is applied, the control electrode wiring C_iControl electrode voltage V_{+ L}_iBy applying, the conductive movable part M of the cantilever structure_{i, j}Flexible, conductive movable part M_{i, j}Free end and detector X_{i, j}In contact with the detector X_{i, j}The heat accumulated in is released by heat conduction. Conductive moving part M_{i, j}Free end and detector X_{i, j}When and are in contact with each other, the conductive movable part M_{i, j}Detector X through the free end of_{i, j}The heat of is instantly transferred to the support substrate (single crystal Si) 1 by heat conduction, and the detector X_{i, j}The temperature of is stable to the temperature before self-heating. Conductive moving part M_{i, j}Free end and detector X_{i, j}In the selected state in which the contact state with is released, when the infrared absorbing layer 42 is irradiated with infrared rays, the temperature of the infrared absorbing layer 42 rises due to the self-heating phenomenon corresponding to the infrared intensity.

As shown in the equivalent circuit of FIG. 3, in the infrared imaging apparatus according to the first embodiment, the vertical address circuit 101 and the horizontal address circuit 102 are arranged adjacent to each other in the row direction and the column direction of the imaging region. ing. Horizontal address line W in the vertical address circuit 101_i-1, W_i, W_{i + 1}, ... are connected, and the horizontal selection line H is connected to the horizontal address circuit 102._j-1, H_j, H_{j + 1}, ... are connected. Infrared imager detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i-1, j-1}, X_{i-1, j}, X_{i-1, j + 1}, , is the corresponding vertical signal line B_j-1, B_j, B_{j + 1}, ... and horizontal address line W_i-1, W_i, W_{i + 1}It is connected between ,. Vertical signal line B in each row as a constant current source to obtain the pixel output voltage_j-1, B_j, B_{j + 1}Load MOS transistor T_d_j-1, T_d_j, T_d_{j + 1}, ... are connected. Load MOS transistor T_d_j-1, T_d_j, T_d_{j + 1}The substrate voltage Vss is applied to the source of ,. In FIG. 3, the conductive movable part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}The mechanical switching element is displayed as represented by. Resistance r shown in Figure 3_{i-1, j-1}, r_{i-1, j}, , r_{i, j-1}, r_{i, j}Is the thermal resistance and conductive moving part M of the infrared absorbing layer 42 shown in FIG._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Represents the thermal resistance which is the total thermal contact resistance when the infrared ray absorbing layer 42 is brought into contact with the infrared ray absorbing layer 42. Conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}As shown in FIG. 2, most of the heat is generated by the nitride film (third interlayer insulating film) 34, the oxide film (second interlayer insulating film) 33b, and the oxide film (first interlayer insulating film). It flows to the substrate (1,2,4) through the interlayer insulating film (33a), but this heat flow is not shown in the equivalent circuit of FIG.

Horizontal address line W selected by vertical address circuit 101._i-1, W_i, W_{i + 1}The horizontal address line W, to which the power supply voltage Vd is applied and is not selected by the vertical address circuit 101._i-1, W_i, W_{i + 1}The substrate voltage Vss is applied to ... As a result, the detector X of the selected row_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}The pn junction inside, ... becomes a forward bias and a bias current flows, and the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}The operating point is determined by the temperature of the internal pn junction and the forward bias current, and the vertical signal line B of each row_j-1, B_j, B_{j + 1}, ... to detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}, ... signal output voltage is generated. At this time, the detector X that is not selected by the vertical address circuit 101_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}The pn junction of, ... has a reverse bias. That is, the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1}_{, j}, X_{i + 1, j + 1}, The internal pn junction is the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}, It has a selection function.

[0023] Vertical signal line B_j-1, B_j, B_{j + 1}The voltage generated in, ... is extremely low, and the vertical signal line B_j-1, B_j, B_{j + 1}It is necessary to reduce the voltage to generate noise (for example, 5 μV) or less. The value of this noise is, for example, about 1/80 of the noise of a CMOS sensor which is a MOS type visible light image sensor. In order to amplify this low voltage signal voltage, the amplification / readout circuit A for each column_j-1, A_j, A_{j + 1}, ... are arranged, and the amplification transistor T of each row_A_j-1, T_A_j, T_A_{j + 1}, ... gates and vertical signal lines in each row B_j-1, B_j, B_{j + 1}, ... is the coupling capacity C_cj-1, C_cj, C_{cj + 1}Capacitive coupling is performed by ,. This coupling capacitance C_cj-1, C_cj, C_{cj + 1}, ..., vertical signal line B_j-1, B_j, B_{j + 1}, ... and amplification read circuit A_j-1, A_j, A_{j + 1}, ... is separated in DC.

[0024] Amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}On the drain side of, ..., the storage capacity Cs for integrating and accumulating the current-amplified signal current._j-1, Cs_j, Cs_{j + 1}, ... are connected. The storage time for integrating the signal current is determined by the horizontal address line W by the vertical address circuit 101._i-1, W_i, W_{i + 1}, ... is determined by the row selection pulse applied to. Storage capacity Cs_j-1, Cs_j, Cs_{j + 1}, ..., this storage capacity Cs_j-1, Cs_j, Cs_{j + 1}Reset transistor T for resetting the voltage of_R_j-1, T_R_j, T_R_{j + 1}, ... are connected, and the horizontal selection transistor S_j-1, S_j, S_{j + 1}The reset operation is performed after the reading of the signal voltage is completed.

[0025] Amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}The drain of, ... is the sample transistor T_S_j-1, T_S_j, T_S_{j + 1}Amplification transistor T via ..._A_j-1, T_A_j, T_A_{j + 1}It is connected to the gate of, ..., and the sample transistor T_S_j-1, T_S_j, T_S_{j + 1}By turning on, ..., the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}The gate and drain of, ... have the same potential.

[0026] FIG. 4 is a timing chart for explaining the operation of the infrared imaging apparatus according to the first embodiment. Load MOS transistor T not displayed on the timing chart_d_j-1, T_d_j, T_d_{j + 1}, Source potential and amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}The source potentials of, ... all give the substrate voltage Vss, and the reset transistor T_R_j-1, T_R_j, T_R_{j + 1}The power supply voltage is given to the drain voltage of ,.

The leftmost period in FIG. 4 indicates a non-selection period. That is, the horizontal address line W on the first line, which is not shown in FIG.₁Is selected Selection period T_SELBefore, there is a non-selection period during which the vertical address circuit 101 does not perform row selection. Amplification transistor T in this non-selection period_A_j-1, T_A_j, T_A_{j + 1}Performs the operation of acquiring and saving the threshold information of ,. During this non-selection period, the vertical signal line B_j-1, B_j, B_{j + 1}The voltage of ... is the load MOS transistor T_d_j-1, T_d_j, T_d_{j + 1}Since it is equal to the source voltage of, ..., the board voltage is Vss. In the non-selection period, first, the reset transistor T_R_j-1, T_R_j, T_R_{j + 1}Turn on, ... and store capacity Cs_j-1, Cs_j, Cs_{j + 1}, Voltage V_cj-1, V_cj, V_{cj + 1}, ... is reset. Next, the sample transistor T_S_j-1, T_S_j, T_S_{j + 1}Turn on, ... and the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}Amplification transistor T reset to power supply voltage at the gate_A_j-1, T_A_j, T_A_{j + 1}, ... Gives the drain voltage. Therefore, the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}, ... is turned on and drain current flows. Drain voltage V due to this drain current_cj-1, V_cj, V_{cj + 1}, ... is lowered and the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}The gate voltage in the state where the conductance is lowered and the drain current does not flow is the drain voltage V._cj-1, V_cj, V_{cj + 1}, ... is acquired. This voltage is the amplification transistor T for each row._A_j-1, T_A_j, T_A_{j + 1}, ... is the threshold voltage. Amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}, ... Threshold information is drain voltage V_cj-1, V_cj, V_{cj + 1}Sample transistor T after being read to_S_j-1, T_S_j, T_S_{j + 1}By turning off, ..., the threshold information is the coupling capacitance C._cj-1, C_cj, C_{cj + 1}, ... will be held. Since this threshold information is read once within the frame period, it is not performed before the selection of the second and subsequent rows, and the threshold information held before the selection of the first row is used as it is. Next, the reset transistor T_R_j-1, T_R_j, T_R_{j + 1}Turn on, ... and drain voltage V_cj-1, V_cj, V_{cj + 1}, ... is reset.

[0028] The selection period T of the first line following the non-selection period_SELIn the horizontal address line W₁Row selection pulse V₁Is applied.

[0029] In FIG. 4, the horizontal address line W is at 1/60 second intervals.₁, W₂, , W_i-1, W_i, W_{i + 1}, ... for 20 μsec, row selection pulse V₁, V₂, , V_i-1, V_i, V_{i + 1}, ... is applied. Horizontal address line W₁Row selection pulse V₁Control electrode wiring C until 10 μs before is applied₁Control electrode voltage V_{+ L1}Is applied, and the conductive moving part M_{1, j-1}, M_1,j, M_{1,j + 1}, ... and detector X_{1, j-1}, X_1,j, X_{1,j + 1}, ... are in contact with each other and set to the temperature before self-heating. And the horizontal address line W₁Row selection pulse V₁Control electrode wiring C connected to the control electrode 37 10 μs before the application of₁Conductive moving part M by applying 0V to_{1, j-1}, M_1,j, M_{1,j + 1}, ... and detector X_{1, j-1}, X_1,j, X_{1,j + 1}Release the contact with ,. Conductive moving part M_{1, j-1}, M_1,j, M_{1,j + 1}Moving part wiring G connected to, ..._j-1, G_j, G_{j + 1}A constant voltage of 0 V is applied to ... And the detector X_{1, j-1}, X_1,j, X_{1,j + 1}By irradiating, ... with infrared rays, the detector X_{1, j-1}, X_1,j, X_{1,j + 1}, ... Raise the temperature. In this state, the horizontal address line W₁Row selection pulse V₁Is applied, the load MOS transistor T_d_j-1, T_d_j, T_d_{j + 1}, Vertical signal line B_j-1, B_j, B_{j + 1}, ~ Detection unit X on the first line_{1, j-1}, X_1,j, X_{1,j + 1}, ~ Horizontal address line W on the first line₁~ Load MOS transistor T through the current path of vertical address circuit 101_d_j-1, T_d_j, T_d_{j + 1}The bias current determined by ... This bias current and detector X_{1, j-1}, X_1,j, X_{1,j + 1}Depending on the temperature of the pn junction, which is a thermoelectric conversion means, the detector X_{1, j-1}, X_1,j, X_{1,j + 1}The operating point of, ... is determined, and the detector X_{1, j-1}, X_1,j, X_{1,j + 1}Detector X that changes depending on the temperature of ..._{1, j-1}, X_1,j, X_{1,j + 1}, ... The output voltage of each row is the vertical signal line B_j-1, B_j, B_{j + 1}Occurs in ... And the vertical signal line B_j-1, B_j, B_{j + 1}The voltage of, ... is from the board voltage Vss to the detector X_{1, j-1}, X_1,j, X_{1,j + 1}It changes to the output voltage of ,.

[0030] This vertical signal line B_j-1, B_j, B_{j + 1}The voltage change of, ... is the coupling capacitance C_cj-1, C_cj, C_{cj + 1}Amplification transistor T by coupling by ..._A_j-1, T_A_j, T_A_{j + 1}, ... Change the gate voltage. Therefore, the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}The gate voltage of, ... is the amplification transistor T held during the non-selection period._A_j-1, T_A_j, T_A_{j + 1}, Threshold information of detector X_{1, j-1}, X_1,j, X_{1,j + 1}The output voltage change information of, ... is added. As a result, the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}, ... is turned on and the drain current corresponding to the vertical signal line voltage flows, and the storage capacity Cs_j-1, Cs_j, Cs_{j + 1}, ... and the selection period T on the first line_SELDuring the period, the current is integrated and the drain voltage V_cj-1, V_cj, V_{cj + 1}, ... changes. At this time, the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}Since the gate voltage that governs the drain current of ,, ..., is determined by the amount of shift from the held threshold voltage, it is not affected by the threshold that varies from column to column. And the first line selection period T_SEL10 μs after the end of, again, the control electrode wiring C₁Control electrode voltage V_{+ L1}Is applied, and the conductive moving part M_{1, j-1}, M_1,j, M_{1,j + 1}, ... and detector X_{1, j-1}, X_1,j, X_{1,j + 1}If you put the, ... in contact with, the detector X_{1, j-1}, X_1,j, X_{1,j + 1}The heat accumulated in ... can be released.

[0031] First line selection period T_SEL1st line following horizontal read period T_READIn addition, the horizontal selection transistor S by the horizontal address circuit 102_j-1, S_j, S_{j + 1}, ... are selected in sequence and the drain voltage V_cj-1, V_cj, V_{cj + 1}, ... are read out to the horizontal signal line 104 in chronological order.

[0032] The operation of the second and subsequent lines is the sample transistor T._S_j-1, T_S_j, T_S_{j + 1}It is the same as the operation in the first line except that there is no operation of ,.

[0033] For example, in the i-th row, as shown in FIG. 4, the drain current in the selection period of the i-th row is integrated and read out sequentially. That is, the horizontal address line W_iRow selection pulse V_iControl electrode wiring C until 10 μs before is applied_iControl electrode voltage V_{+ L}_iIs applied, and the conductive moving part M_{i, j-1}, M_{i, j}, M_{i, j + 1}, ... and detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, ... are in contact with each other and set to the temperature before self-heating. And the horizontal address line W_iRow selection pulse V_iControl electrode wiring C connected to the control electrode 37 10 μs before the application of₁Conductive moving part M by applying 0V to_{i, j-1}, M_{i, j}, M_{i, j + 1}, ... and detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}Release the contact with ,. Conductive moving part M_{i, j-1}, M_{i, j}, M_{i, j + 1}Moving part wiring G connected to, ..._j-1, G_j, G_{j + 1}A constant voltage of 0 V is applied to ... And the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}By irradiating, with infrared rays, the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, ... Raise the temperature. In this state, the horizontal address line W_iRow selection pulse V_iIs applied, and the selection period T of the i-th line is applied._SELIs started. Selection period of line i T_SELIn the load MOS transistor T_d_j-1, T_d_j, T_d_{j + 1}, Vertical signal line B_j-1, B_j, B_{j + 1}, ~ Detector X on line i_{i, j-1}, X_{i, j}, X_{i, j + 1}, ~ Horizontal address line W on line i_i~ Load MOS transistor T through the current path of vertical address circuit 101_d_j-1, T_d_j, T_d_{j + 1}The bias current determined by ... This bias current and detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}Depending on the temperature of the pn junction, which is a thermoelectric conversion means, the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}The operating point of, ... is determined, and the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}Detector X that changes depending on the temperature of ..._{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}, ... The output voltage of each row is the vertical signal line B_j-1, B_j, B_{j + 1}Occurs in ... And the vertical signal line B_j-1, B_j, B_{j + 1}The voltage of, ... is from the board voltage Vss to the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}It changes to the output voltage of ,.

[0034] This vertical signal line B_j-1, B_j, B_{j + 1}The voltage change of, ... is the coupling capacitance C_cj-1, C_cj, C_{cj + 1}Amplification transistor T by coupling by ..._A_j-1, T_A_j, T_A_{j + 1}, ... Change the gate voltage. Therefore, the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}The gate voltage of, ... is the amplification transistor T held during the non-selection period._A_j-1, T_A_j, T_A_{j + 1}, Threshold information of detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}The output voltage change information of, ... is added. As a result, the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}, ... is turned on and the drain current corresponding to the vertical signal line voltage flows, and the storage capacity Cs_j-1, Cs_j, Cs_{j + 1}, ... and i-th line selection period T_SELDuring the period, the current is integrated and the drain voltage V_cj-1, V_cj, V_{cj + 1}, ... changes. At this time, the amplification transistor T_A_j-1, T_A_j, T_A_{j + 1}Since the gate voltage that governs the drain current of ,, ..., is determined by the amount of shift from the held threshold voltage, it is not affected by the threshold that varies from column to column. And the i-th row selection period T_SEL10 μs after the end of, again, the control electrode wiring C₁Control electrode voltage V_{+ L}_iIs applied, and the conductive moving part M_{i, j-1}, M_{i, j}, M_{i, j + 1}, ... and detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}If you put the, ... in contact with, the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}The heat accumulated in ... can be released.

[0035] i-th line selection period T_SELLine i following horizontal read period T_READIn addition, the horizontal selection transistor S by the horizontal address circuit 102_j-1, S_j, S_{j + 1}, ... are selected in sequence and the drain voltage V_cj-1, V_cj, V_{cj + 1}, ... are read out to the horizontal signal line 104 in chronological order.

[0036] As shown in FIG. 4, the operation after the i + 1 line is the same as the operation in the i line, and the drain current in the i + 1 line selection period is integrated and read out sequentially.

Detector X_{i, j}The time change of the temperature of is shown in Fig. 5. Here, as shown in FIG. 6, the conductive movable portion M of the cantilever structure having a width W = 10 μm, a length L = 20 μm, and a thickness t = 0.5 μm._{i, j}Let's examine the heat flow due to. In this case, the cross-sectional area orthogonal to the heat flow S = 10 μm × 0.5 μm = 5 μm²Will be. Conductive moving part M_{i, j}If the material of is Al, the heat capacity C = 1.6 × 10^-9Since J / K and thermal conductivity coefficient G = 237W / (m / K) may be sufficient, the thermal time constant τ = C L / G S = 59μsec (1). Assuming that the frame rate = 120 fps, the vertical scanning period T is 1/120 = 8.3 ms, so that the thermal time constant τ is about two orders of magnitude faster than the vertical scanning period T.

[0038] As described above, according to the infrared imaging apparatus according to the first embodiment, the detection unit X by self-heating generated when a pulse voltage is applied to the thermoelectric conversion unit 41 by using the mechanical switching element._{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}As shown in Fig. 5, it is possible to reset the temperature rise of ,. Therefore, the frame rate can be further increased, and a thermal infrared imaging device having high sensitivity and high response can be provided. Further, even if the frame rate is increased, the heat rise in the detection unit generated by the self-heating phenomenon can be sufficiently reduced by the blanking time, so that the heat destruction phenomenon can be avoided. As a result, it is possible to provide a thermal infrared image pickup device having a frame rate that is about 5 to 10 times higher than that of a conventional thermal infrared camera, which is suitable for nighttime front monitoring of a passenger car.

[0039] Using FIGS. 7 to 14, the microcavity region Q_{i, j}A method of manufacturing an infrared image pickup apparatus according to the first embodiment of the present invention will be described with reference to the pixels of the above. The method for manufacturing the infrared imaging apparatus described below is an example, and it goes without saying that it can be realized by various other manufacturing methods including this example.

(A) First, as shown in FIG. 7 (a), a so-called SOI substrate in which an embedded oxide film 2 and a single crystal Si layer 3 are sequentially laminated on a single crystal Si support substrate 1 is prepared. Next, the device separation region is defined by using a technique such as photolithography, and the single crystal Si layer 3 of the portion where the device separation region is to be formed is etched and removed by a technique such as reactive ion etching (RIE) method. Then, as shown in FIG. 7 (b), the element separation oxide film 4 is embedded by a technique such as chemical vapor deposition (CVD) and flattened by a technique such as chemical mechanical polishing (CMP).

(B) Next, the element-separated oxide film 4 and the embedded oxide film 2 in the region where the first support leg 21 and the second support leg 22 are to be formed shown in FIG. The groove 5 is selectively removed by etching to form a groove 5 as shown in FIG. 7 (c). FIG. 7 (c) is a cross-sectional view taken along the AA direction of FIG. 1, and in the cross-sectional view taken along the BB direction of FIG. 1, a groove portion narrower than that of FIG. 7 (c) is formed at the same time. The first sacrificial Si film 6 is embedded in the groove 5 by a technique such as the CVD method and flattened as shown in FIG. 7 (d) by a technique such as the CMP method. The first sacrificial Si film 6 may be single crystal, polycrystalline, or amorphous. In the flattening step shown in FIG. 7 (d), in order to protect the surface of the single crystal Si layer 3 which is a so-called active region, the surface of the single crystal Si layer 3 is protected by an oxide film or the like prior to the step of forming the groove 5. It is more preferable to carry out the step of performing. Next, the detection unit X is similar to the source / drain regions of the vertical address circuit 101, the horizontal address circuit 102, the moving part driver 103, and the peripheral circuits of the constant current source shown in FIG._{1, j-1}, X_1,j, X_{1,j + 1}, X_{i, j-1}, X_{i, j}, X_{i, j + 1}, , X_{i + 1, j-1}, X_{i + 1, j}, X_{i + 1, j + 1}The n-type impurity region and the n-type impurity region for forming the pn junction diode are formed by selective doping technology such as ion implantation using photolithography technology. Peripheral circuits may be manufactured according to ordinary standard MOS integrated circuit manufacturing methods. Although details are omitted, after forming regions necessary for a standard MOS integrated circuit such as an inversion prevention layer (channel stop region) and an element separation region, the surface of the single crystal Si layer 3 is thermally oxidized to obtain a thickness. A gate oxide film of 50 nm to 100 nm is formed. At this time V_thControlled ion implantation may be added. Next, a polysilicon film is deposited on the entire surface of the gate oxide film by the CVD method at about 300 nm to 600 nm, for example, 400 nm. Next, a photoresist film (hereinafter, simply referred to as "photoresist") is spin-coated on the surface of the polysilicon film. Then, the photoresist is patterned by the photolithography technique. Then, using this photoresist as a mask, the polysilicon film is etched by the RIE method or the like to form a gate electrode and polysilicon wiring (not shown). Then, the photoresist is removed and a new photoresist is spin-coated on the surface of the gate electrode. Then, using the photolithography technique, an ion implantation opening is formed in the MOS transistor forming region to expose the polysilicon gate electrode. Then, using the exposed polysilicon gate electrode and the new photoresist as masks, self-aligned arsenic ions (⁷⁵As⁺) Doze amount 10¹⁵cm^-2Ion implantation in the order of. At this time, arsenic (arsenic) is also applied to the polysilicon gate electrode.⁷⁵As⁺) Is ion-implanted. After removing the new photoresist, the single crystal Si layer 3 is heat-treated to activate and diffuse the injected impurity ions to form an n-type source region and an n-type drain region in the single crystal Si layer 3. However, the n-type source region, n-type drain region, n-type impurity region, n-type impurity region, and the like in the single crystal Si layer 3 are not shown.

(C) Next, as shown in FIG. 8, the oxide film as the first interlayer insulating film 33a is formed on the surface of the single crystal Si layer 3 by a thermal oxidation method or a CVD method to have a thickness of 0.5 μm to 1.0. Form to about μm. 8 to 14, (a) is a cross-sectional view taken along the AA direction of FIG. 1, and (b) is a cross-sectional view taken along the BB direction of FIG. 1, respectively. Further, although not shown, a contact hole is opened at a predetermined position of the first interlayer insulating film 33a for wiring to the source / drain region of the transistor of the peripheral circuit and the pn junction diode. Further, a metal film made of titanium (Ti), tungsten (W) or the like is deposited by a sputtering method, an electron beam vacuum welding method or the like. After that, if the metal film is patterned by the metallization technology using photolithography technology or the like, as shown in FIG. 8 (a), the first detection unit wiring 51 and the second detection unit wiring are used as the first layer metal wiring. 52, horizontal address line W_iAnd control electrode wiring C_iIs formed. Although not shown, adjacent pixels are also similarly connected to the first detection unit wiring 51, the second detection unit wiring 52, and the horizontal address line W._i-1, W_{i + 1}, ... and control electrode wiring C_i-1, C_{i + 1}Of course, ... The second detector wiring 52 of each pixel and the horizontal address line W_i-1, W_i, W_{i + 1}Since they are at the same level (metallation level), they can be electrically connected as a continuous metal pattern. 1st detector wiring 51, 2nd detector wiring 52, horizontal address line W_i-1, W_i, W_{i + 1}, ... and control electrode wiring C_i-1, C_i, C_{i + 1}At the same time, the first layer metal wiring for the peripheral circuit and the pn junction diode is also formed, but these are also omitted from the illustration.

(D) Next, an oxide film as a second interlayer insulating film 33b having a thickness of about 1.0 μm is formed on the first interlayer insulating film 33a by a CVD method. As the second interlayer insulating film 33b, a PSG film, a BSG film, a BPSG film, or the like may be used. Then, after flattening by using the CMP method or the like, as shown in FIG. 9, a nitride film as a third interlayer insulating film 34 having a thickness of about 0.5 μm is formed. Further, a via hole is opened at a predetermined position of the third interlayer insulating film (nitriding film) 34 by hand using a photolithography technique, a RIE method, or the like. For example, the control electrode wiring C shown in FIG._i-1, C_i, C_{i + 1}A via hole 56 is opened at the upper part of ... Further, a via hole is opened at the upper part of the end portion of each first detection unit wiring 51. After that, as shown in FIG. 9B, the control electrode 37 and the vertical signal line B are used as the second layer metal wiring on the third interlayer insulating film 34._jAnd B_{j + 1}To form. From the control electrode 37, as shown in FIG. 1, the control electrode auxiliary wiring 53 is the control electrode wiring C._i-1, C_i, C_{i + 1}, ..... It is formed extending to the via hole 56 formed at the upper part. Therefore, the control electrode wiring C is passed through the via hole 56._i-1, C_i, C_{i + 1}, ..... and each control electrode 37 are electrically connected. Although not shown, the control electrode 37 and the vertical signal line B are also applied to adjacent pixels._j-2, B_j-1, B_{j + 2}, B_{j + 3}Of course, ... Therefore, the upper part of the end of the first detector wiring 51 of each pixel and the vertical signal line B_j-2, B_j-1, B_j, B_{j + 1}, B_{j + 2}, B_{j + 3}, ... are electrically connected via a via hole. Control electrode 37 and vertical signal line B_j-2, B_j-1, B_j, B_{j + 1}, B_{j + 2}, B_{j + 3}At the same time, the second layer metal wiring for the peripheral circuit is also formed, but these are also omitted from the illustration. As shown in FIG. 2, the first interlayer insulating film 33a, the second interlayer insulating film 33b, and the third interlayer insulating film 34 play the role of the infrared absorbing layer 42 and the role of the interlayer insulating film and the passivation film. (E) Next, the groove portions 76a and 77a are formed at the positions of the peripheral portions of the first support leg 21 and the second support leg 22 planned to be formed by the RIE method or the ECR ion etching method. Further, as shown in FIG. 11, a second sacrificial Si film 7 having a thickness of 1.5 to 3.0 μm is deposited so as to fill the grooves 76a and 77a. Further, as shown in FIG. 11, the surface of the second sacrificial Si film 7 is flattened by using the CMP method or the like.

(F) Then, by selectively repeating etching of different depths using the photolithography technique and RIE, the depth on the surface of the second sacrificial Si film 7 is as shown in FIG. 12 (b). Form different grooves 37a, 37b, 37c. The groove 37c is performed until the nitride film 34 is exposed. Next, as the third layer metal wiring, an aluminum alloy film (Al-Si, Al-Cu-Si) is formed to a thickness of about 0.5 μm to 1 μm by a sputtering method, an electron beam vacuum deposition method, or the like. A photoresist mask is formed on this using photolithography technology, and the aluminum alloy film is patterned by RIE using this mask, and as shown in FIG. 13, the conductive movable portion M_{i, j}Form the pattern of. Conductive moving part M_{i, j}The pattern of is the vertical signal line B_j₊₁It is a cantilever structure in which a support portion (post) is provided between the pattern of the control electrode 37 and the pattern of the control electrode 37.

(G) Then, as shown in FIG. 14, the second sacrificial Si film 7 is removed with a silicon etching solution. When a part of the surface of the support substrate 1 exposed by this etching is subsequently anisotropically etched using an anisotropic etchant of single crystal Si, for example, a chemical solution such as TMAH, as shown in FIG. Microcavity region Q_{i, j}Is formed, and the infrared imaging apparatus according to the first embodiment of the present invention is completed.

[0046] In the above description, the etching removal step of the first sacrificial Si film 6 and the second sacrificial Si film 7 and the subsequent anisotropic etching step of the support substrate 1 have been described independently. Since the chemicals used are basically the same chemicals, in the actual process, after the shape of FIG. 13 is obtained, etching with a chemical such as TMAH is performed without being aware of the shape of FIG. , The final shape of the structure shown in Fig. 2 can be obtained.

Although the method of manufacturing the infrared image pickup apparatus using the SOI substrate has been described in FIGS. 7 to 14, it is also possible to manufacture the infrared image pickup apparatus without using the SOI substrate. A method of manufacturing an infrared imaging apparatus according to a modified example (first modified example) of the first embodiment of the present invention will be described with reference to FIGS. 15 and 16.

(A) First, peripheral circuits such as a vertical address circuit 101, a horizontal address circuit 102, a movable part driver 103, and a constant current source are formed on the main surface of the Si substrate 31. Next, for the MOS integrated circuit of the peripheral circuit, a base oxide film 32 that functions as an interlayer insulating film is deposited to a thickness of about 1 μm. For example, the base oxide film 32 is a composite composed of a two-layer structure consisting of an oxide film having a film thickness of about 0.5 μm deposited by the CVD method and a PSG film or a BPSG film having a film thickness of about 0.5 μm on the oxide film. A film is fine. The BPSG film on the upper layer of this composite film is reflowed to flatten the surface of the underlying oxide film 32. Next, as shown in FIG. 15A, the groove portion 61, selectively exposes a part of the surface of the Si substrate 31 to the underlying oxide film 32 by using the photolithography technique and the RIE method. 62,63 will be provided. These grooves 61, 62, 63 are the first detection unit wiring 51, the thermoelectric conversion unit 41, the first detection unit wiring forming groove portion 61 for forming the second detection unit wiring 52, and the thermoelectric conversion unit forming groove portion 62. And the second detection unit wiring forming groove portion 63. Then, as shown in FIG. 15A, the sheath layer (SiO) is formed on the surface of the underlying oxide film 32 provided with the grooves 61, 62, 63.₂Membrane) 35 is deposited by the CVD method.

(B) And the sheath layer (SiO)₂Bolometer polysilicon 41 with a thickness of 1.0 to 1.5 μm is deposited so as to fill the grooves 61, 62, 63 covered with the film) 35. Furthermore, using CMP, as shown in FIG. 15 (b), the surface of the bolometer polysilicon 41 is subjected to a sheath layer (SiO).₂Flatten until the membrane) 35 is exposed, and embed the bolometer polysilicon 41 inside each of the grooves 61, 62, 63. Although not shown, after this, p⁺Prepare a type-doped polysilicon 41, and this p⁺A cathode region may be formed by selectively implanting n-type impurity ions onto the surface of the type-doped polysilicon 41 to form a pn junction diode.

(C) Next, using an etching mask made of a photoresist, a bolometer polysilicon 41 embedded inside each of the first detection portion wiring forming groove portion 61 and the second detection portion wiring forming groove portion 63. Etching and removing. Further, the photoresist used as an etching mask is used as a lift-off mask, and a metal film 64 made of Ti is deposited by a sputtering method, an electron beam vacuum deposition method, or the like. After that, if the photoresist used as the lift-off mask is removed, a metal film made of Ti is embedded inside each of the first detection portion wiring forming groove portion 61 and the second detection portion wiring forming groove portion 63. Further, using the CMP method, as shown in FIG. 15 (c), the surface of the metal film is flattened until the underlying oxide film 32 is exposed, and the level of the surface of the metal film made of Ti is adjusted to the underlying oxide film 32. Match the surface level of the bolometer polysilicon 41. As a result, the first detection unit wiring 51 and the second detection unit wiring 52 made of Ti have the base oxide film 32 and the base oxide film 32 inside the groove portion 61 for forming the wiring of the first detection unit and the groove portion 63 for forming the wiring of the second detection unit. It is embedded via the device separation oxide film 4. Further, using the photoresist patterned using the photolithography technique as a mask, the substrate oxide film 32 is etched by the RIE method, the ECR ion etching method, or the like, and the peripheral circuits 101, 102, 103, ... A contact hole is opened for each transistor constituting the ... Then, the photoresist used for forming this contact hole is removed. Next, a W film is formed to a thickness of about 0.5 μm by a sputtering method, an electron beam vacuum welding method, or the like. On this, an etching mask of a photoresist is formed by using a photolithography technique, and the W film is patterned using this etching mask by the RIE method to obtain peripheral circuits 101, 102, 103, Embed contact plugs for each transistor that composes. At the same time, as shown in Fig. 15 (c), the horizontal address line W_iAnd control electrode wiring C_iForm the pattern of. Although not shown, the horizontal address line W is also applied to adjacent pixels._i-1, W_{i + 1}, ... and control electrode wiring C_i-1, C_{i + 1}, ... are formed. Horizontal address line W_i-1, W_i, W_{i + 1}, ... and control electrode wiring C_i-1, C_i, C_{i + 1}At the same time, metal wiring for peripheral circuits and the like is also formed, but these are also omitted from the illustration. At this time, the bolometer polysilicon 41 and the first detection unit wiring 51 and the second detection unit wiring 52 embedded in each of the support leg groove portions 61 and 63 are connected by a W film. In addition, the second detector wiring 52 and the horizontal address line W of each pixel_i-1, W_i, W_{i + 1}, ... are connected to each other.

(D) After that, as shown in FIG. 15 (d-1), an oxide film 33 having a thickness of about 0.5 μm to 1.5 μm and a nitride film 34 having a thickness of 0.5 μm are deposited on the entire surface by the CVD method. .. FIG. 15 (d-1) is a cross-sectional view of FIG. 1 as viewed from the AA direction. The composite film composed of the oxide film 33 and the nitride film 34 is the detection unit X._{i, j}In, it functions as an infrared absorbing layer 42, but in peripheral circuits 101, 102, 103, ..., It functions as an interlayer insulating film. Then, using the photoresist patterned using photolithography technology as a mask, the interlayer insulating films 33 and 34 are etched by the RIE method or the ECR ion etching method, etc., and the peripheral circuits 101, 102, 103, ... 1st layer metal wiring, 1st detector wiring 51 and vertical signal line B_jOpen a via hole for the connecting metal (plug) for connecting with the pattern of. Next, as the second layer metal wiring, an aluminum alloy film (Al-Si, Al-Cu-Si) containing silicon or the like is formed to a thickness of about 0.5 μm by a sputtering method, an electron beam vacuum deposition method, or the like. On top of this, a photoresist mask is formed using photolithography technology, and this mask is used to pattern an aluminum alloy film by the RIE method to construct peripheral circuits 101, 102, 103, .... At the same time as the via plug for each transistor, as the second layer metal wiring, as shown in Fig. 15 (d-2), the vertical signal line B_j₊₁And the pattern of the control electrode 37 is formed at the same time. FIG. 15 (d-2) is a cross-sectional view in a direction orthogonal to FIG. 15 (d-1), which corresponds to the case of being viewed from the BB direction of FIG. In the following description, FIGS. 16 (e-2) and 16 (f-2) are cross-sectional views similarly viewed from the BB direction of FIG. 1, and FIGS. 16 (e-1) and 16 (f-1) are Similarly, it is a cross-sectional view seen from the AA direction of FIG. Although not shown in FIG. 15 (d-2), the control electrode 37 and the vertical signal line B are similarly applied to adjacent pixels._j-1, B_j, B_{j + 2}, B_{j + 3}Of course, ... Therefore, the upper part of the end of the first detector wiring 51 of each pixel and the vertical signal line B_j-2, B_j-1, B_j, B_{j + 1}, B_{j + 2}, B_{j + 3}, ... are electrically connected via a via hole. Control electrode 37 and vertical signal line B_j-1, B_j, B_{j + 1}, B_{j + 2}, B_{j + 3}At the same time, metal wiring for peripheral circuits is also formed, but these are also omitted from the illustration. After that, this second layer metal wiring and vertical signal line B_j-2, B_j-1, B_j, B_{j + 1}, B_{j + 2}, B_{j + 3}Remove the photoresist used for patterning ,.

(E) Then, the nitride film 34, the control electrode wiring 37, and the second layer metal wiring B._j-2, B_j-1, B_j, B_{j + 1}, B_{j + 2}, B_{j + 3}Apply a new photoresist on top of ... In addition, the photoresist is patterned using photolithography techniques. Using this patterned photoresist, the nitride film 34 and the oxide film 33 are selectively etched and removed by the RIE method, the ECR ion etching method, or the like to form a groove. Further, a sacrificial polysilicon film 36 having a thickness of 1.5 to 3.0 μm is deposited so as to fill the groove. Further, the CMP method is used to flatten the surface of the sacrificial polysilicon film 36 as shown in FIGS. 16 (e-1) and 16 (e-2).

(F) After that, by selectively repeating etching of different depths using the photolithography technique and the RIE method, grooves having different depths are formed on the surface of the sacrificial polysilicon film 36. Further, the control electrode 37 of each pixel and the vertical signal line B_j-1, B_j, B_{j + 1}, B_{j + 2}, B_{j + 3}The sacrificial polysilicon film 36 at the position between each of, ... Is selectively removed until the nitride film 34 is exposed, and a contact hole is opened. Next, as the third layer metal wiring, an aluminum alloy film (Al-Si, Al-Cu-Si) is formed to a thickness of about 0.5 μm to 1 μm by a sputtering method, an electron beam vacuum deposition method, or the like. A photoresist mask was formed on this using photolithography technology, and the aluminum alloy film was patterned using this mask by the RIE method in FIGS. 16 (f-1) and (f-2). As shown in, conductive moving part M_{i, j}Form the pattern of. Conductive moving part M_{i, j}The pattern of is the control electrode 37 and the vertical signal line B._{j + 1}It is a cantilever structure with a support part (post) between the patterns. Similarly, the conductive moving part M_{i, j-1}, M_{i, j + 1}, M_{i, j + 2}, M_{i, j + 3}The pattern of, ... is the control electrode 37 of each pixel and the vertical signal line B._j-1, B_{j + 1}, B_{j + 2}, B_{j + 3}It is a cantilever structure with a support part (post) between the patterns.

(G) After that, if the sacrificial polysilicon film 36 is removed with a silicon etching solution and a part of the surface of the Si substrate 31 exposed by this etching is subsequently removed with a silicon etching solution, the same as in FIG. Microcavity region Q_{i, j}Is formed, and the infrared imaging apparatus according to the modified example (first modified example) of the first embodiment of the present invention is completed. In this case, the "base" of the present invention is composed of a Si substrate 31 and an underlying oxide film 32 on the Si substrate 31.

FIG. 17 shows an infrared imaging apparatus according to another modification (second modification) of the first embodiment (corresponding to a cross-sectional view taken along the BB direction in FIG. 1). Unlike FIG. 2, a microcavity region is shallowly formed on the surface of the substrate composed of the Si substrate 31 and the underlying oxide film 32 on the Si substrate 31. Therefore, the conductive movable part M of the cantilever structure_{i, j}And detector X_{i, j}In the state of contact with, the detector X_{i, j}Sinks downward due to elastic deformation, and its bottom comes into contact with the Si substrate 31. Horizontal address line W_iRow selection pulse V_iIs applied, and the detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}When, ... is selected, the conductive movable part M_{1, j-1}, M_1,j, M_{1,j + 1}, ... and detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}, ... is in a non-contact state. In this case, as shown in FIG. 17, it is elastic and the detector X_{i, j}The bottom of is lifted from the Si substrate 31 and the detector X_{i, j}The bottom of the is in a non-contact state with the Si substrate 31. That is, in the blanking state, the thermal resistance is reduced to improve the heat flow, and at the same time, the conductive movable portion M is used._{1, j-1}, M_1,j, M_{1,j + 1}, ... and the corresponding detector X_{i, j-1}, X_{i, j}, X_{i, j + 1}Since stress deformation due to contact with each other is reduced, mechanical strength can be maintained and the service life is long.

(Second Embodiment) In the thermal infrared imaging apparatus according to the first embodiment of the present invention, the control electrode 37 is the detection unit X._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}It was arranged on the surface of the support substrate (single crystal Si) 1 surrounding the ... In the thermal infrared imaging device according to the second embodiment of the present invention, as shown in FIGS. 18 and 19, the control electrode 38 is the detection unit X._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}It differs from the first embodiment in that it is arranged inside. Further, in the second embodiment, the case where the substrate is composed of the Si substrate 31 and the underlying oxide film 32 on the Si substrate 31 will be described, but it goes without saying that the substrate may have an SOI structure.

That is, the mechanical switching element of the thermal infrared imaging device according to the second embodiment is the movable portion wiring G arranged on the surface of the substrate (31, 32)._j-2, G_j-1, G_jConductive of a cantilever structure that is electrically connected to, ..., has a fixed end fixed to the substrate (31, 32), and has a free end extending from the fixed end side to the upper part of the detection unit. Moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}, ... and the control electrode wiring C arranged on the surface of the substrate (31, 32)_i-1, C_i, C_{i + 1}It is provided with a control electrode 38 electrically connected to, ..., And arranged on the surface of the detection unit. Moving part wiring G_j-2, G_j-1, G_jThe voltage supplied to the moving part via, ... and the control electrode wiring C_i-1, C_i, C_{i + 1}By adjusting the voltage supplied to the control electrode 38 via ..._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Contact or bring each free end of, ... to the detection unit. Inside the second support leg 22, the thermoelectric conversion unit 41 is connected to the horizontal address line W, respectively._i-1, W_i, W_{i + 1}Control electrode 38 and control electrode wiring C together with the second detector wiring 52 connected to ,._i-1, C_i, C_{i + 1}The control electrode auxiliary wiring 53 for connecting to, ... Is housed.

[0058] In this way, the control electrode 38 is detected by the detection unit X._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j} The control electrode 38 that functions as a mechanical switching element by arranging it inside and the conductive movable part M that faces it._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}The effective area of the electrode portions of, ... Is increased, and as a result, the heat dissipation switch can be operated at a low voltage.

(Third Embodiment) As shown in FIG. 20, the planar structure of the thermal infrared imaging apparatus according to the third embodiment of the present invention is the same as that of the thermal infrared imaging apparatus according to the first embodiment. Similarly, the control electrode 37 is the detector X._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}It is arranged on the surface of the Si substrate 31 that surrounds it. That is, the mechanical switching element of the thermal infrared image pickup apparatus according to the third embodiment is the movable part wiring G arranged on the surface of the substrate (31, 32)._j-2, G_j-1, G_jConductive of a cantilever structure that is electrically connected to, ..., has a fixed end fixed to the substrate (31, 32), and has a free end extending from the fixed end side to the upper part of the detection unit. Moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}, ... and the control electrode wiring C arranged on the surface of the substrate (31, 32)_i-1, C_i, C_{i + 1}It is provided with a control electrode 37 that is electrically connected to, ..., And is arranged between the fixed end and the free end on the surface of the substrate (31, 32).

However, as is clear from the cross-sectional structure along the BB direction of FIG. 20 shown in FIG. 21, the detection unit X_{i, j}Is a conductive moving part M_{i, j}Infrared absorbing layer 42 that is placed above and absorbs infrared rays, and the conductive moving part M_{i, j}The thermoelectric conversion unit 41, which is arranged below the infrared absorption layer 42 and converts the heat generated in the infrared absorption layer 42 into an electric signal, thermally connects the infrared absorption layer 42 and the thermoelectric conversion unit 41, and the infrared absorption layer 42 is thermoelectric. It is provided with support portions 54a, 54b, 54c, 54d that mechanically support the conversion portion 41. That is, the infrared absorption layer 42 of each pixel has an umbrella structure supported by four support portions 54a, 54b, 54c, 54d. However, in FIG. 21, only 54a and 54b of the four support portions are shown, and the support portions 54c and 54d in front of the cross section (paper surface) are not shown. In FIG. 20, a two-dot chain line (imaginary line) is shown by the infrared absorption layer 42, and the structures of the four support portions 54a, 54b, 54c, and 54d connected under the infrared absorption layer 42 are clarified.

[0061] The infrared absorption layer 42 is connected to the thermoelectric conversion unit 41 via four support portions (conductive support portions) 54a, 54b, 54c, 54d having high thermoconductivity. In the thermal infrared imaging apparatus according to the third embodiment, the composite film composed of the oxide films 33a and 33b and the nitride film 34 above the thermoelectric conversion unit 41 merely functions as an interlayer insulating film. As is clear from FIG. 21, the conductive movable part M of the cantilever structure_{i, j}Is arranged between the infrared absorption layer 42 and the thermoelectric conversion unit 41.

[0062] In the first embodiment and the second embodiment, the metallic conductive movable portion M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Is placed on the infrared absorbing layer 42, so the infrared rays emitted are the conductive moving part M._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Is reflected by, and the infrared absorption rate decreases. In the structure of the third embodiment shown in FIGS. 20 and 21, the infrared absorbing layer 42 is the conductive movable portion M._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Since it is located above, all the irradiated infrared rays can be absorbed by the infrared absorption layer 42. Therefore, the infrared absorption rate of the thermal infrared imaging apparatus according to the third embodiment becomes extremely high. Further, as shown by the alternate long and short dash line (imaginary line) in FIG. 20, the infrared absorbing layer 42 can have a structure overhanging a wide area up to the region above the Si substrate 31. That is, the aperture ratio of infrared absorption of each pixel of the thermal infrared imaging apparatus according to the third embodiment can be sufficiently increased as compared with the first and second embodiments. In FIG. 20, if the regions of the alternate long and short dash lines (imaginary lines) are expanded to be adjacent to each other, it is possible to reduce the dead space that becomes a dead space of infrared rays.

(Fourth Embodiment) In the thermal infrared imaging apparatus according to the second embodiment shown in FIGS. 18 and 19, the control electrode 38 is detected by the detection unit X._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j} The control electrode 38 that is placed inside and functions as a mechanical switching element and the conductive movable part M that faces it._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}The effective area of the electrode portions of, ... Is increased, and as a result, the heat dissipation switch can be operated at a low voltage. However, as is clear from FIG. 18, the control electrode 38 reduces the infrared absorption aperture ratio of each pixel.

[0064] In the thermal infrared imaging device according to the fourth embodiment of the present invention shown in FIG. 22, the control electrode 38 is the detection unit X, as in the thermal infrared imaging device according to the second embodiment._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j} It is located inside. However, the infrared absorbing layer 42 of each pixel has an umbrella structure supported by four support portions 54a, 54b, 54c, 54d, as in the third embodiment. In FIG. 23, only 54a and 54b of the four support portions are shown, and the support portions 54c and 54d in front of the cross section (paper surface) are not shown. The region indicated by the alternate long and short dash line (imaginary line) in FIG. 22 is the infrared absorption layer 42.

[0065] As described in the third embodiment, the infrared absorbing layer 42 is provided with the thermoelectric conversion unit 41 via four support portions (conductive support portions) 54a, 54b, 54c, 54d having high thermoconductivity. It is connected to the. And the conductive movable part M of the cantilever structure_{i, j}Is arranged between the infrared absorption layer 42 and the thermoelectric conversion unit 41. That is, the infrared absorbing layer 42 is the conductive moving part M._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Since it is located above, all the irradiated infrared rays can be absorbed by the infrared absorption layer 42. Therefore, the infrared absorption rate of the thermal infrared imaging apparatus according to the fourth embodiment becomes extremely high, and at the same time, it is possible to have an advantage that the heat dissipation switch can be operated at a low voltage.

(Fifth Embodiment) As shown in FIG. 24, the infrared imaging apparatus according to the fifth embodiment of the present invention has a plurality of vertical signal lines B._j-1, B_j, B_{j + 1}, ... and these multiple vertical signal lines B_j-1, B_j, B_{j + 1}Multiple horizontal address lines W extending in the vertical direction with respect to ..._i-1, W_i, W_{i + 1}Detection unit X that constitutes each pixel inside the matrix composed of ..._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}... is arranged in two dimensions. Detection unit X of each pixel_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}... is the corresponding vertical switching transistor T_{i-1, j-1}, T_{i-1, j}, , T_{i, j-1}, T_{i, j}....., and are connected to each other via the wiring 52 of the second detection unit. That is, the detection unit X of each pixel_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}One of the electrodes is the corresponding vertical switching transistor T._{i-1, j-1}, T_{i-1, j}, , T_{i, j-1}, T_{i, j}It is connected to the drain electrode of ... For example, as shown in FIG. 26, the detection unit X of each pixel._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}However, if it is composed of a pn junction diode, then the pn junction diode X_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}One of the electrodes (anode electrode) is the corresponding vertical switching transistor T._{i-1, j-1}, T_{i-1, j}, , T_{i, j-1}, T_{i, j}The drain electrodes of ... Are connected to each other via the wiring 52 of the second detection unit. Detection unit X of each pixel_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}The other electrode of ... Is connected to a common potential (for example, ground potential). Vertical switching transistor T_{i-1, j-1}, T_{i-1, j}, , T_{i, j-1}, T_{i, j}The gate electrode of ..... is the horizontal address line W for each row._i-1, W_i, W_{i + 1},·····It is connected to the. Vertical switching transistor T_{i-1, j-1}, T_{i-1, j}, , T_{i, j-1}, T_{i, j}The source electrode of ..... is the vertical signal line B for each row._j-1, B_j, B_{j + 1},·····It is connected to the. In addition, the vertical signal line B_j-1, B_j, B_{j + 1}In parallel with, ..., moving part wiring G_j-2, G_j-1, G_j, ... is running. Also, the horizontal address line W_i-1, W_i, W_{i + 1}In parallel with, ..., control electrode wiring C_i-1, C_i, C_{i + 1}, ... is running.

[0067] FIG. 25 (a) is a cross-sectional view taken along the AA direction of FIG. 24, and FIG. 25 (b) is a cross-sectional view taken along the BB direction of FIG. 24._{i, j}However, the microcavity area Q_{i, j}It is shown that it is stored in a hollow state inside. This hollow structure is the detector X_{i, j}Is formed to be thermally separated from the Si substrate 31. As shown in FIGS. 24 and 25 (a), the detector X constituting each pixel_{i, j}Supports the Si substrate 31 and the underlying oxide film 32 on the upper part of the Si substrate 31 in a hollow state by the first support legs 21 and the second support legs 22 having large thermal resistance, and maintains a thermally separated state. are doing. Microcavity area Q_{i, j}Is configured in an inverted pyramid shape at the bottom of a recess in which a part of the Si substrate 31 is selectively removed. A vertical switching transistor T is part of the surface of the Si substrate 31._{i, j}The source region 71 and the drain region 72 of the above are formed. Vertical switching transistor T inside the underlying oxide film 32 located between the source region 71 and the drain region 72_{i, j}The gate electrode 73 of is embedded. Detector X shown in FIG. 24_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}As shown in FIG. 25, there are an infrared absorption layer 42 that absorbs incident infrared rays and converts them into heat, and a thermoelectric conversion that converts temperature changes due to heat generated in the infrared absorption layer 42 into electric signals, respectively. Includes part 41. The thermoelectric conversion unit 41 has a structure in which a pn junction diode selectively doped with impurities is integrated on the surface of the polysilicon layer. The bottom surface and the side surface of the polysilicon layer 41 are covered with a sheath layer 35 made of an oxide film, respectively. Doped polysilicon, VO instead of pn junction diode₂, Ti and other bolometers can be used. An oxide film as an interlayer insulating film 33 is arranged on the thermoelectric conversion unit 41. A nitride film 34 is arranged on the upper part of the oxide film 33. The infrared absorbing layer 42 is composed of a composite film composed of an oxide film 33 and an upper nitrided film 34. The infrared absorption layer 42 is arranged in substantially the same shape as the thermoelectric conversion unit 41.

As shown in FIGS. 24 and 25 (a), inside the first support leg 21, the first detection unit wiring 51 and the second support leg that connect the thermoelectric conversion unit 41 to a common potential (ground potential). Inside 22 is a thermoelectric converter 41 and a vertical switching transistor T._{i, j}To the drain electrode_iThe second detector wiring 52 connected to is embedded. The first detection unit wiring 51 and the second detection unit wiring 52 may be composed of refractory metals such as W, Ti, Co, and Mo, these silicides, or polysides using these silicides.

[0069] Further, as shown in FIGS. 24 and 25 (b), each pixel is provided with a control electrode 37. The control electrode 37 of each pixel is connected to the control electrode wiring C via the control electrode auxiliary wiring 53._i-1, C_i, C_{i + 1}Connected to, ..., control electrode wiring C_i-1, C_i, C_{i + 1}A voltage is applied via ,. As shown in FIG. 25 (b), the conductive movable portion M of the cantilever structure faces the control electrode 37 of each pixel._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}, ... is provided, and the conductive movable part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}, ... is the moving part wiring G_j-2, G_j-1, G_j,·····It is connected to the. Conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}In each of, ..., The fixed end is fixed to the surface of the laminated structure composed of the underlying oxide film 32, the oxide film 33, and the nitride film 34 on the upper part of the Si substrate 31, and the detection unit X is fixed from the fixed end side._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}The structure is such that the free end extends to the upper part. Control electrode 37, conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}A mechanical switching element is configured by the above. This conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}For ..., Conductive materials such as Al, Cu, Ti, TiN, and W are suitable.

[0070] FIG. 25 shows the horizontal address line W._iRow selection pulse V_iDetector X in the state where_{i, j}Indicates the selected state of. Row selection pulse V_iIn the blanking state immediately before is applied, the control electrode wiring C_iControl electrode voltage V_{+ L}_iBy applying, the conductive movable part M of the cantilever structure_{i, j}Flexible, conductive movable part M_{i, j}Free end and detector X_{i, j}In contact with the detector X_{i, j}The heat accumulated in is released by heat conduction. Conductive moving part M_{i, j}Free end and detector X_{i, j}When and are in contact with each other, the conductive movable part M_{i, j}Detector X through the free end of_{i, j}Heat is transferred to the Si substrate 31 by heat conduction in an instant, and the detector X_{i, j}The temperature of is stable to the temperature before self-heating. Conductive moving part M_{i, j}Free end and detector X_{i, j}In the selected state in which the contact state with is released, when the infrared absorbing layer 42 is irradiated with infrared rays, the temperature of the infrared absorbing layer 42 rises corresponding to the infrared intensity.

[0071] In the equivalent circuit of FIG. 26, the conductive movable portion M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}The mechanical switching element is displayed as represented by. Resistance r shown in FIG._{i-1, j-1}, r_{i-1, j}, , r_{i, j-1}, r_{i, j}Is the thermal resistance and conductive moving part M of the infrared absorbing layer 42 shown in FIG._{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Represents the thermal resistance which is the total thermal contact resistance when the infrared ray absorbing layer 42 is brought into contact with the infrared ray absorbing layer 42. Conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}As shown in FIG. 25, most of the heat flows to the substrate (31, 32) through the nitride film 34 and the oxide film 33 when the infrared ray absorbing layer 42 is brought into contact with the infrared ray absorbing layer 42. The equivalent circuit of FIG. 26 is not shown. In the equivalent circuit of FIG. 26, for example, the horizontal address line W at 1/60 second intervals.₁, W₂, , W_i-1, W_i, W_{i + 1}, ... for 20 μsec, row selection pulse V₁, V₂, , V_i-1, V_i, V_{i + 1}, ... is applied. Horizontal address line W₁Row selection pulse V₁Control electrode wiring C until 10 μs before is applied₁Control electrode voltage V_{+ L1}Is applied, and the conductive moving part M_{1, j-1}, M_1,j, M_{1,j + 1}, ... and detector X_{1, j-1}, X_1,j, X_{1,j + 1}, ... are in contact with each other and set to the temperature before self-heating. And the horizontal address line W₁Row selection pulse V₁Control electrode wiring C connected to the control electrode 37 10 μs before the application of₁Conductive moving part M by applying 0V to_{1, j-1}, M_1,j, M_{1,j + 1}, ... and detector X_{1, j-1}, X_1,j, X_{1,j + 1}Release the contact with ,. Conductive moving part M_{1, j-1}, M_1,j, M_{1,j + 1}Moving part wiring G connected to, ..._j-1, G_j, G_{j + 1}A constant voltage of 0 V is applied to ... And the detector X_{1, j-1}, X_1,j, X_{1,j + 1}By irradiating, ... with infrared rays, the detector X_{1, j-1}, X_1,j, X_{1,j + 1}, ... Raise the temperature. In this state, the horizontal address line W₁Row selection pulse V₁Is applied, and the horizontal selection transistor S is applied by the horizontal address circuit 102._j-1, S_j, S_{j + 1}When, ... are selected in sequence, the vertical signal line B_j-1, B_j, B_{j + 1}Detection unit X via ..._{1, j-1}, X_1,j, X_{1,j + 1}The signals of, ... Are read out to the horizontal signal line 104 in chronological order.

[0072] As described above, according to the infrared imaging apparatus according to the fifth embodiment, the detection unit X due to self-heating generated when a pulse voltage is applied to the thermoelectric conversion unit 41 by using the mechanical switching element._{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j}It is possible to reset the temperature rise. Therefore, the frame rate can be further increased, and a thermal infrared imaging device having high sensitivity and high response can be provided. Further, even if the frame rate is increased, the heat rise in the detection unit generated by the self-heating phenomenon can be sufficiently reduced by the blanking time, so that the heat destruction phenomenon can be avoided.

(Other Embodiments) As described above, the present invention has been described according to the first to fifth embodiments, but the statements and drawings that form part of this disclosure limit the invention. It should not be understood that there is. Various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art from this disclosure.

[0074] In the description of the first to fifth embodiments already described, the conductive movable portion M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Although a metal material is used as the material, the conductive moving part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}It suffices if a material that generates an attractive force by the control electrode 37 is used for a part of. Also, the conductive movable part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}Although a voltage of 0 V is applied to the device, it may be floating, and if the mechanical switching element operates in the same manner as in the first to fifth embodiments, the control electrode 37 and the conductive movable part M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j}The combination of voltages given to is free.

[0075] In the description of the first to fifth embodiments already described, the conductive movable portion M of the cantilever structure in the blanking state._{i, j-1}Flexible, conductive movable part M_{i, j-1}And detector X_{i, j-1}In contact with the detector X_{i, j-1}The case where the heat accumulated in the water is released by heat conduction has been described. However, the conductive moving part M_{i, j-1}And detector X_{i, j-1}The conductive movable part M can be used as a mechanical switching element that does not make a perfect contact with and is brought close to each other through a micro gap (gap) of about 0.5 to 0.1 μm or less._{i, j-1}And detector X_{i, j-1}A heat flow due to radiation can be formed between and. Since the heat flow due to radiation is smaller than that of heat conduction, the thermal resistance r shown in FIGS. 3 and 26_{i-1, j-1}, r_{i-1, j}, , r_{i, j-1}, r_{i, j}The value of becomes large. However, the conductive moving part M_{i, j-1}And detector X_{i, j-1}Since physical fatigue due to mechanical contact with the device can be avoided, it is effective in extending the life of the thermal infrared image pickup device. Conductive moving part M_{i, j-1}And detector X_{i, j-1}In order to secure a micro gap between the and the conductive movable part M, a spacer of a predetermined height is used._{i, j-1}It may be provided between the surface of the support substrate (single crystal Si) 1 and the surface of the support substrate (single crystal Si) 1.

[0076] In the description of the first to fifth embodiments already described, a two-dimensional infrared image pickup device (area type infrared image pickup device) having an XY matrix composed of a vertical signal line and a horizontal address line has been described. .. However, it goes without saying that a one-dimensional infrared image pickup device (line type infrared image pickup device) may be used with one horizontal address line as it is.

[0077] As described above, it goes without saying that the present invention includes various embodiments not described here. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention relating to the reasonable claims from the above description.

[Effectiveness of the Invention] According to the present invention, it is possible to provide a thermal infrared imaging apparatus that does not decrease the sensitivity even if the frame rate is increased and does not cause thermal destruction due to a self-heating phenomenon. You can.

BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1] FIG. 1 is a plan view showing a part (2 × 2 part) of an array of pixels of an infrared imaging apparatus according to a first embodiment of the present invention.

FIG. 2A is a cross-sectional view taken along the AA direction of FIG. 1, and FIG. 2B is a cross-sectional view taken along the BB direction.

FIG. 3 is a simplified equivalent circuit including a peripheral circuit of an infrared imaging device (sensor array) according to the first embodiment of the present invention.

FIG. 4 is a timing chart showing the relationship between the readout voltage applied to the vertical signal line in the infrared imaging apparatus according to the first embodiment of the present invention and the control electrode voltage applied to the control electrode wiring. is there.

FIG. 5 is a diagram showing a temporal change in the temperature of a detection unit in the infrared imaging apparatus according to the first embodiment of the present invention.

FIG. 6 is a schematic view illustrating the dimensions of the cantilever structure for examining the heat flow by the moving portion of the cantilever structure in the infrared imaging apparatus according to the first embodiment of the present invention.

FIG. 7 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 1).

FIG. 8 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 2).

FIG. 9 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 3).

FIG. 10 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 4).

FIG. 11 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 5).

FIG. 12 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 6).

FIG. 13 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 7).

FIG. 14 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a first embodiment of the present invention (No. 8).

FIG. 15 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a modification (first modification) of the first embodiment of the present invention (No. 1).

FIG. 16 is a process cross-sectional view illustrating a method of manufacturing an infrared image pickup apparatus according to a modification (first modification) of the first embodiment of the present invention (No. 2).

FIG. 17 is a cross-sectional view of pixels of an infrared imaging device according to another modification (second modification) of the first embodiment of the present invention.

FIG. 18 is a plan view showing a part (2 × 2 part) of the pixel arrangement of the infrared image pickup apparatus according to the second embodiment of the present invention.

19 is a cross-sectional view taken along the BB direction of FIG.

FIG. 20 is a plan view showing a part (2 × 2 part) of the pixel arrangement of the infrared image pickup apparatus according to the third embodiment of the present invention.

21 is a cross-sectional view taken along the BB direction of FIG. 20. FIG.

FIG. 22 is a plan view showing a part (2 × 2 part) of the pixel arrangement of the infrared image pickup apparatus according to the fourth embodiment of the present invention.

FIG. 23 is a cross-sectional view taken along the BB direction of FIG. 22;

FIG. 24 is a plan view showing a part (2 × 2 part) of the pixel arrangement of the infrared image pickup apparatus according to the fifth embodiment of the present invention.

25 (a) is a cross-sectional view taken along the AA direction of FIG. 24, and FIG. 25 (b) is a cross-sectional view taken along the BB direction of FIG. 24.

FIG. 26 is a simplified equivalent circuit including a peripheral circuit of an infrared imaging device (sensor array) according to a fifth embodiment of the present invention.

FIG. 27 is a diagram showing a temporal change in the temperature of the detection unit due to a self-heating phenomenon in a conventional thermal infrared image pickup apparatus (when the frame rate is low).

FIG. 28 is a diagram showing a temporal change in the temperature of the detection unit due to a self-heating phenomenon in a conventional thermal infrared image pickup apparatus (when the frame rate is high). It is a top view which shows a part of the array of pixels.

[Explanation of Code] 1 Support substrate (single crystal Si) 2 Embedded oxide film 3 Single crystal Si layer 4 Element separation oxide film 5,76a, 76b, 77a, 77b Groove 6 First sacrificial Si film 7 Second sacrificial Si film 21 1st support leg 22 2nd support leg 31 Substrate (Si substrate) 32 Base oxide film 33 Oxide film 33a 1st interlayer insulating film (oxide film) 33b 2nd interlayer insulating film (oxide film) 34 Nitride film (3rd interlayer insulation) Film) 35 Sheath layer 36 Sacrificial polysilicon film 37,38 Control electrode 37a, 37b, 37c Groove 41 Thermoelectric conversion unit (single crystal Si layer or borometer polysilicon) 42 Infrared absorption layer 51 1st detector Wiring 52 2nd detector Wiring 53 Control electrode auxiliary wiring 54a, 54b, 54c, 54d Support part 55 Polysilicon for cavity formation 61 1st detection part Wiring formation groove 62 Thermoelectric conversion part formation groove 63 2nd detection part Wiring formation groove 64 Metal film 76 , 77 Slit part 83 Photoresist 71 Source area 72 Drain area 73 Gate electrode 7374 Gate oxide film 101 Vertical address circuit 102 Horizontal address circuit 103 Moving part driver 104 Horizontal signal line 105 Constant current source A_j-1, A_j, A_{j + 1} Amplification read circuit B_j-1, B_j, B_{j + 1} Vertical signal line C_cj-1, C_cj, C_{cj + 1} Bonding capacity C_i_-1, Ci, C_i₊₁ Control electrode wiring Cs_j-1, Cs_j, Cs_{j + 1} Storage capacity G_j-1, G_j, G_{j + 1} Moving part wiring H_j-1, H_j, H_{j + 1}Horizontal selection line M_{i-1, j-1}, M_{i-1, j}, , M_{i, j-1}, M_{i, j} Moving part W_i-1, W_i, W_{i + 1} Horizontal address line Q_{i, j-1}, Q_{i, j} Microcavity region r_{i-1, j-1}, r_{i-1, j}, , r_{i, j-1}, r_{i, j} Resistor S_j-1, S_j, S_{j + 1} Horizontal switch transistor T_{i-1, j-1}, T_{i-1, j}, T_{i, j-1}, T_{i, j} Vertical switching transistor T_d_j-1, T_d_j, T_d_{j + 1} Load MOS transistor T_A_j-1, T_A_j, T_A_{j + 1} Amplification transistor T_R_j-1, T_R_j, T_R_{j + 1} Reset transistor T_S_j-1, T_S_j, T_S_{j + 1} Sample transistor X_{i-1, j-1}, X_{i-1, j}, , X_{i, j-1}, X_{i, j} Detector