Semiconductor device, its manufacturing method, and spacer manufacturing method

The present invention relates to a semiconductor device including a semiconductor chip such as a sound pressure sensor chip or a pressure sensor chip, a method for manufacturing the same, and a method for manufacturing a spacer used in the semiconductor device.

Conventionally, in semiconductor devices such as silicon microphones and pressure sensors, semiconductor chips having a diaphragm that detects pressure fluctuations such as sound by vibration, such as sound pressure sensor chips and pressure sensor chips, are mounted on the surface of a circuit board. (See, for example, Patent Document 1). When this type of semiconductor chip is arranged on the surface of the circuit board, a cavity is formed between the diaphragm and the surface of the circuit board.

Here, when the volume of the cavity is small, the air spring constant of the cavity becomes large and the diaphragm is less likely to vibrate, so that the displacement amount of the diaphragm becomes small and the pressure fluctuation cannot be detected accurately. .. That is, it is necessary to vibrate the diaphragm to secure a sufficient size as a cavity. Further, the volume of the cavity needs to be appropriately changed according to the characteristics of the semiconductor chip. In the conventional semiconductor device, the volume of the hollow portion is expanded by forming a recessed recess from the surface of the circuit board.<patcit num="1"><text>Special Table 2004-537182 Gazette</text></patcit>

<p> However, in the above-mentioned conventional semiconductor device, since the recess for securing the volume of the cavity is formed in the circuit board, the manufacturing of the circuit board becomes troublesome, the manufacturing efficiency of the semiconductor device is lowered, and the semiconductor device is manufactured. There is a risk that the manufacturing cost of The present invention has been made in view of the above circumstances, and is a semiconductor device capable of suppressing changes in the vibration characteristics of the diaphragm while improving manufacturing efficiency and reducing manufacturing costs, a manufacturing method thereof, and a semiconductor device. It is an object of the present invention to provide a method for manufacturing a spacer used in the above.</p>

<p> In order to solve the above problems, the present invention proposes the following means. The invention according to claim 1 comprises a circuit board or a package in which a circuit is incorporated, a semiconductor chip arranged on the circuit board or the surface of the package and provided with a thin film diaphragm that vibrates in response to pressure fluctuations. A substantially plate-shaped spacer fixed between the circuit board or the package and the semiconductor chip is provided, and a through hole is formed in the spacer so that the surface of the circuit board or the package and the diaphragm face each other. We are proposing a semiconductor device that is characterized by this.</p><p> According to the semiconductor device according to the present invention, in a state where the semiconductor chip is provided on the surface of the circuit board via the spacer, a cavity is formed by the surface of the circuit board, the diaphragm of the semiconductor chip, and the through hole of the spacer. become. The volume of this cavity can be easily changed by simply changing the thickness dimension of the spacer and the size of the through hole. As a result, the volume of this cavity can be made larger. That is, in this semiconductor device, it is not necessary to separately process the circuit board to form a recess as in the conventional case.</p><p> The invention according to claim 2 is the semiconductor device according to claim 1, wherein the spacer is defined by the surface of the circuit board or the package, the diaphragm and the through hole, and the outside of the cavity. We are proposing a semiconductor device characterized by allowing the flow of gas based on the static pressure difference with the outer space located on the lateral side and blocking the passage of gas based on the pressure fluctuation acting on the diaphragm. ..</p><p> Further, the invention according to claim 3 proposes a semiconductor device according to claim 1 or 2, wherein the spacer is made of a porous material. Further, the invention according to claim 4 proposes a semiconductor device according to claim 1 or 2, wherein a communication hole is formed in the spacer.</p><p> Here, the package in which the circuit is incorporated refers to a package in which a microphone chip already assembled in the same package and an LSI for microphone output signal processing are assembled, and includes wiring. For example, a premolded package in which a lead frame is molded, or a premolded package in which an LSI having functions such as an impedance converter, a charge pump, and an amplifier is die-bonded can be mentioned. The static pressure refers to the pressure in the cavity or the outer space in a state where the gas does not flow and is stationary. Further, the change in static pressure is such that the change in pressure per unit time is relatively small, for example, heating / cooling of a cavity, generation of outgas during reflow in which a spacer is bonded to a semiconductor chip or a circuit board, etc. The static pressure change in the cavity and the static pressure change in the outer space based on the altitude difference and the like are included in the static pressure change. Further, the pressure fluctuation indicates a dynamic pressure change due to acoustics or the like, and includes a pressure change having a larger pressure change per unit time than the above-mentioned static pressure change. That is, the above-mentioned static pressure change in the cavity and the static pressure change in the outer space are not included in this pressure fluctuation.</p><p> By the way, there is a difference in static pressure between the cavity and the outer space caused by the pressure change caused by heating / cooling of the semiconductor device and the static pressure change of the outer space based on the altitude difference. In some cases, even when the spacer is formed to increase the volume of the cavity according to the invention of claim 1, it may not be sufficient to alleviate the difference in static pressure. Therefore, according to the invention of claim 2, between the surface of the circuit board or the package, the cavity defined by the diaphragm and the through hole, and the outer space located on the outer side of the cavity. By providing a spacer characterized by allowing the flow of gas based on the static pressure difference and blocking the passage of gas based on the pressure fluctuation acting on the diaphragm, even if the above difference occurs, the cavity and the cavity are provided. Since the diaphragm can be prevented from being deformed due to the difference in static pressure with the outer space, it is possible to reliably prevent the vibration characteristics of the diaphragm from changing.</p><p> Further, according to the invention of claim 3, the semiconductor device according to claim 1 or 2 allows the flow of gas based on the static pressure difference and prevents the passage of gas based on the pressure fluctuation acting on the diaphragm. Therefore, in addition to adjusting the pressure difference, when pressure fluctuations such as acoustics reach the diaphragm and a dynamic pressure difference occurs between the outer space and the cavity based on this, Since the inflow and outflow of gas through the gaps of the porous body is appropriately blocked, the diaphragm can be vibrated with high accuracy even with respect to the above pressure fluctuation. Here, "moderately blocking" means blocking a value higher than the frequency of the sound that a human begins to hear when there is a time fluctuation of pressure.</p><p> Further, according to the invention of claim 4, the semiconductor device according to claim 1 or 2 allows the flow of gas based on the static pressure difference and prevents the passage of gas based on the pressure fluctuation acting on the diaphragm. By adjusting the pressure difference. For example, when a pressure fluctuation such as sound reaches the diaphragm and a dynamic pressure difference is generated between the outer space and the cavity based on this, the gas enters and exits appropriately through the communication hole. Since it is blocked, the diaphragm can be vibrated with high accuracy even with respect to the pressure fluctuation.</p><p> Further, the spacer does not need to be formed in a thin film shape like a diaphragm, or to include an electrical wiring portion inside the spacer like a circuit board. Therefore, as compared with the case where a similar communication hole is formed on the circuit board, a fine communication hole that restricts the ingress and egress of gas between the cavity and the outer space can be easily formed in the spacer. It is also possible to form the spacer itself from a porous body. Therefore, it is possible to improve the manufacturing efficiency of the semiconductor device and reduce the manufacturing cost of the semiconductor device.</p><p> The invention according to claim 5 is the semiconductor device according to claim 4, wherein the spacer is a substantially plate-shaped base substrate, a thin film-shaped first film layer formed on the surface of the base substrate, and the like. A thin film-like second film layer formed on the surface of the first film layer is provided, and the communication holes are formed through a slit-shaped notch formed in the first film layer and the notch. We have proposed a semiconductor device characterized in that it is defined by the front surface of the base substrate and the back surface of the second film layer facing each other. According to the semiconductor device according to the present invention, a slit-shaped notch is formed in the first film layer, and the first film layer is sandwiched between the base substrate and the second film layer to facilitate communication holes. Can be formed into.</p><p> The invention according to claim 6 proposes a semiconductor device according to any one of claims 1 to 5, wherein the spacer is formed so as to be elastically deformable. There is. According to the semiconductor device according to the present invention, even if the circuit board vibrates, the vibration can be absorbed by the elastic force of the spacer, so that the diaphragm can be prevented from vibrating based on the vibration of the circuit board. That is, it is possible to prevent the vibration of the circuit board from being detected as noise in the diaphragm. In addition, the stress associated with the curing of the adhesive during die bonding can be relaxed.</p><p> The invention according to claim 7 proposes a semiconductor device according to any one of claims 1 to 6, wherein the spacer has a thermal expansion coefficient close to that of the semiconductor chip. are doing. According to the semiconductor device according to the present invention, even if the spacer and the semiconductor chip are heated or cooled, stress is not generated in the diaphragm because the spacer and the semiconductor chip have a coefficient of thermal expansion close to each other. When the circuit board and the spacer have significantly different coefficients of thermal expansion, the semiconductor device is heated or cooled, and the space between the circuit board and the spacer is based on the above-mentioned difference in the coefficient of thermal expansion. Stress is generated in the spacer, and this stress can be relieved in the spacer. Therefore, it is possible to prevent stress from being generated in the diaphragm and changing its vibration characteristics.</p><p> The invention according to claim 8 is the semiconductor device according to any one of claims 1 to 7, wherein the spacer is formed with an engaging recess recessed from the surface facing the semiconductor chip, and the semiconductor is formed. We propose a semiconductor device characterized in that the chip engages with the engaging recess and is attached to the spacer. According to the semiconductor device according to the present invention, by engaging the semiconductor chip with the engaging recess, it is possible to easily position the semiconductor chip with respect to the spacer when manufacturing the semiconductor device.</p><p> The invention according to claim 9 is fixed between a circuit board or a package in which a circuit is incorporated and a semiconductor chip having a thin-film diaphragm that vibrates in response to pressure fluctuations, and the circuit board or the package. A method for manufacturing a spacer having through holes for facing each other between the surface and the diaphragm, the first thin film forming a thin film-like first film layer that can be etched on the surface of a substantially plate-shaped base substrate. In the forming step, the first film layer is etched so that the first film layer reaches the edge of the surface along the surface of the base substrate from the surface of the first film layer. A thin film is formed on the surface of the first film layer so as to form an etching step of forming a slit-shaped notch to be recessed and a communication hole that covers the notch and communicates from the through hole to the end. We propose a method for manufacturing a spacer, which comprises a second thin film forming step for forming the second film layer.</p><p> The invention according to claim 10 is a semiconductor chip provided with a circuit board or a package in which a circuit is incorporated, and a thin film diaphragm arranged on the circuit board or the surface of the package and vibrating in response to pressure fluctuations. And a substantially plate-shaped spacer fixed between the circuit board or the package and the semiconductor chip, and the spacer is provided with a through hole for making the surface of the circuit board or the package and the diaphragm face each other. In the method for manufacturing the formed semiconductor device, the first thin film forming step in which the spacer forms a thin film-like first film layer that can be etched on the surface of a substantially plate-shaped base substrate, and the first thin film forming step. The film layer is etched, and a slit-shaped notch recessed from the surface of the first film layer so as to reach the edge of the surface along the surface of the base substrate from the through hole. A thin film-like second film layer is formed on the surface of the first film layer so as to form a communication hole that covers the notch and communicates from the through hole to the end portion. We propose a method for manufacturing a semiconductor device, which is characterized by being manufactured by a second thin film forming step of forming. According to the method for manufacturing a spacer and a semiconductor device according to the present invention, since the notch portion forming the communication hole is formed by etching, the width dimension of the notch portion can be adjusted with high accuracy. That is, a notch having a small width can be easily formed.</p>

<p> According to the invention of claim 1, the volume of the cavity can be easily changed only by appropriately changing the thickness of the spacer and the size of the through hole. Therefore, the strength of the air spring in the cavity can be changed. It can be adjusted so that the vibration of the diaphragm is not suppressed. Therefore, it is possible to manufacture a product including a high-quality semiconductor device.</p><p> Further, according to the invention according to any one of claims 2 to 4, the static pressure in the cavity and the outer space is abbreviated by allowing gas to flow in and out through the communication holes and the gaps between the porous bodies. Since it can be made equivalent, it is possible to surely prevent the vibration characteristics of the diaphragm from changing. In addition, even if a dynamic pressure difference occurs between the outer space and the cavity based on pressure fluctuations such as acoustics, the ingress and egress of gas through the communication holes and the gaps of the porous body is restricted. The diaphragm can be vibrated with high accuracy in response to the pressure fluctuation. Further, it is easier to form a communication hole in the spacer or to form the spacer itself from a porous body than to form a similar communication hole in the circuit board, so that the manufacturing efficiency of the semiconductor device can be improved. , It is possible to reduce the manufacturing cost of the semiconductor device.</p><p> Further, according to the invention of claim 5, the communication hole can be easily formed only by sandwiching the first film layer having the slit-shaped notch formed between the base substrate and the second film layer to form a spacer. Can be formed. Further, according to the invention of claim 6, since the vibration of the circuit board can be prevented from being detected as noise, it is possible to detect only the pressure fluctuation such as sound with higher accuracy.</p><p> Further, according to the invention of claim 7, since the spacer and the semiconductor chip have a coefficient of thermal expansion close to each other, stress is generated in the diaphragm of the semiconductor chip based on the difference in the coefficient of thermal expansion from the circuit board. It is possible to suppress the change in the vibration characteristics of the diaphragm. Further, according to the invention of claim 8, since the semiconductor chip can be easily positioned with respect to the spacer, the manufacturing efficiency of the semiconductor device can be improved.</p><p> Further, according to the inventions of claims 9 and 10, since the notch portion forming the communication hole can be formed by etching, a fine communication hole can be easily formed.</p>

1 to 11 show an embodiment of the present invention. As shown in FIG. 1, the semiconductor device 1 according to this embodiment is fixed to the circuit board 3, the substantially plate-shaped spacers 5 and IC7 fixed to the surface 3a of the circuit board 3, and the surface 5a of the spacer 5. It is equipped with a semiconductor chip 9. Further, the semiconductor device 1 is provided with a lid portion 11 which is arranged on the surface 3a of the circuit board 3 and covers the spacer 5, the IC 7, and the semiconductor chip 9. The circuit board 3 is composed of a so-called multi-layer wiring board provided with an electrical wiring portion (not shown) inside the circuit board 3, and is electrically connected to the IC 7 and the semiconductor chip 9.

The lid portion 11 has a substantially plate-shaped upper end wall portion 13 arranged at a position separated from the surface 3a of the circuit board 3 in the thickness direction, and a substantially annular side wall fixed to the peripheral edge of the surface 3a of the circuit board 3. It has a part 15. That is, the lid portion 11 is formed in a substantially concave shape that opens toward the tip end portion side of the side wall portion 15 by the upper end wall portion 13 and the side wall portion 15. Therefore, in a state where the tip end portion of the side wall portion 15 is arranged on the surface 3a of the circuit board 3, the hollow space (outer space) S1 is defined by the circuit board 3 and the lid portion 11. The hollow space S1 communicates with an outer space located outside the semiconductor device 1 through an opening 14 formed in the upper end wall portion 13.

The semiconductor chip 9 is a so-called sound pressure sensor chip that converts sound into an electric signal. That is, the semiconductor chip 9 includes a diaphragm 9a that vibrates in response to pressure fluctuations such as sound from an outer space located outside the semiconductor device 1. The diaphragm 9a is configured to vibrate in the thickness direction of the semiconductor chip 9. The IC 7 is for operating the semiconductor chip 9, for example, an amplifier circuit for amplifying an electric signal from the semiconductor chip 9, a DSP (digital signal processor) for processing the electric signal as a digital signal, and the like. Includes A / D converter, etc. This IC 7 is fixed to the surface 3a of the circuit board 3 via an adhesive 12 such as silver paste.

The spacer 5 is fixed to the circuit board 3 via an adhesive 16 such as silver paste between the back surface 5b and the front surface 3a of the circuit board 3. The spacer 5 is formed with a through hole 17 penetrating in the thickness direction thereof. In the semiconductor chip 9 described above, an adhesive 18 such as silver paste is used so that the through hole 17 is covered with the diaphragm 9a and the diaphragm 9a faces the surface 3a of the circuit board 3 through the through hole 17. It is fixed to the surface 5a of the spacer 5. That is, the through hole 17 forms a cavity S2 between the diaphragm 9a and the circuit board 7. The hollow portion S2 communicates with the hollow space S1 through a fine communication hole 19 formed in the spacer 5. In the state where the circuit board 3, the spacer 5 and the semiconductor chip 9 are fixed to each other, there is no gap between the circuit board 3 and the spacer 5 and between the spacer 5 and the semiconductor chip 9. That is, the hollow space S1 and the hollow portion S2 are communicated with each other only by the communication hole 19 described above.

The communication hole 19 is large enough to allow gas to flow between the hollow space S1 and the cavity S2 based on the static pressure difference when a static pressure difference occurs between the hollow space S1 and the cavity S2. It is formed in the space. Here, the static pressure in this embodiment indicates the pressure of the hollow space S1 and the hollow portion S2 in a stationary state without the gas flowing. The change in static pressure is based on, for example, the static pressure change in the cavity S2 due to the generation of outgas during the heating / cooling of the semiconductor device 1 and the reflow of the adhesives 16 and 18, and the altitude difference. The static pressure change in the outer space and the hollow space S1 is included in the static pressure change.

Further, even if a pressure difference occurs between the pressure of the hollow space S1 and the pressure of the hollow portion S2 due to the pressure fluctuation such as acoustics acting on the diaphragm 9a, the communication hole 19 is between the hollow space S1 and the hollow portion S2. It is formed in a size that blocks the passage of gas. Here, the pressure fluctuation indicates a dynamic pressure change due to acoustics or the like, and includes a pressure change having a larger pressure change per unit time than the above-mentioned static pressure change. That is, the above-mentioned static pressure change of the cavity S2 and the static pressure change of the outer space and the hollow space S1 are not included in this pressure fluctuation.

As shown in FIGS. 2 and 3, the spacer 5 is formed by sequentially laminating a thin film-shaped first film layer 23 and a second film layer 25 on the surface 21a of a substantially plate-shaped base substrate 21. .. Holes 27,29,31 having a substantially circular shape in a plan view are formed in the base substrate 21, the first film layer 23, and the second film layer 25, respectively, and the spacers are formed by these three holes 27,29,31. The through hole 17 of 5 is configured. Further, in the first film layer 23, two slit-shaped notches 33 are formed along the surface 21a of the base substrate 21, and these two notches 33 and the base substrate facing each other through the two notches 33 are formed. Two communication holes 19 of the spacer 5 are formed by the front surface 21a of 21 and the back surface 25b of the second film layer 25.

Next, a manufacturing method of the semiconductor device 1 configured as described above will be described. When manufacturing this semiconductor device 1, the spacer 5 having the above-described configuration is manufactured in advance. That is, when manufacturing the spacer 5, first, as shown in FIGS. 5 and 6, a substantially plate-shaped base substrate 21 having substantially circular holes 27 in a plan view is prepared. Next, as shown in FIGS. 7 to 9, a thin film-like first film layer 23 is formed on the surface 21a of the base substrate 21 so as to cover the holes 27 of the base substrate 21 (first thin film forming step). The first film layer 23 is formed of a material that can be etched. After that, a resist layer (not shown) is formed on the surface 23a of the first film layer 23 excluding the notch 33 and the hole 29, and the notch 33 and the hole 29 are formed by etching (etching). ). The notch 33 is formed so as to be recessed from the surface 23a of the first film layer 23 so as to reach the end of the surface 21a along the surface 21a of the base substrate 21. After the etching process is completed, the resist layer described above is removed. Further, when the first film layer 23 is formed from a material capable of etching such as a dry film, at least the dry film itself becomes a resist material, so that a thin film forming step (lamination step) and exposure are performed. The notch 33 and the hole 29 can be formed by going through the steps and the developing steps.

Then, as shown in FIGS. 2 to 4, a second film layer 25 is formed on the surface 23a of the first film layer 23 so as to cover the notch 33 and the holes 27 and 29 (second thin film forming step). ). The second film layer 25, like the first film layer 23, is also formed of a material that can be etched. After the completion of the second thin film forming step, a resist layer (not shown) is formed on the surface 5a of the second film layer 25 excluding the portion where the holes 31 are formed, and the holes are formed by etching. Finally, the resist layer described above is removed to complete the production of the spacer 5. Although the manufacturing method in the case of forming one spacer has been described here, the present invention is not limited to this. For example, the base substrate 21 is formed from one large plate-shaped member, and the first plate-shaped member is formed. The film layer 23 and the second film layer 25 may be laminated, or a large number of holes 27, 29, 31 may be formed and then cut into individual spacers 5 by dicing. In this case, since a large number of notched portions 33 and holes 27, 29, 31 can be formed at once by one etching process, it is possible to improve the manufacturing efficiency of the spacer 5.

Then, the semiconductor device 1 shown in FIG. 1 is assembled using the spacer 5 manufactured as described above. That is, first, as shown in FIG. 10, a substantially annular side wall portion 15 is fixed to the peripheral edge of the surface 3a of the circuit board 3, and the IC7 and the spacer are fixed to the surface 3a of the circuit board 3 via the adhesives 12 and 16. Fix 5. In this case, the spacers 5 and IC7 may be arranged after the adhesives 12 and 16 are adhered to the surface 3a of the circuit board 3 in advance. The gap between the front surface 3a of the circuit board 3 and the back surface 5b of the spacer 5 can be filled with this adhesive 16. Next, the IC 7 is electrically connected to the circuit board 3. Then, as shown in FIG. 11, the semiconductor chip 9 is fixed to the surface 5a of the spacer 5 via the adhesive 18. In this case, the semiconductor chip 9 may be arranged after the adhesive 18 is previously attached to the surface 5a of the spacer 5. Finally, as shown in FIG. 1, the manufacturing of the semiconductor device is completed by fixing the upper end wall portion 13 to the side wall portion 15 to form the lid portion 11. It should be noted that this manufacturing process is only an example. For example, after adhering the semiconductor chip 9 to the spacer 5, the spacer 5 may be fixed to the surface 3a of the circuit board 3.

According to the above-mentioned semiconductor device 1, the volume of the cavity S2 defined by the surface 3a of the circuit board 3, the diaphragm 9a of the semiconductor chip 9, and the through hole 17 of the spacer 5 is the thickness dimension of the spacer 5 and the through hole 17 It can be easily changed by simply changing the size of. Therefore, it is possible to suppress an increase in the air spring constant of the cavity S2 and suppress a change in the vibration characteristics of the diaphragm 9a. Further, since the hollow portion S2 can be formed without separately processing the circuit board 3 to form a recess as in the conventional case, the manufacturing cost of the semiconductor device 1 can be suppressed to a low level.

In addition, the hollow space S2 and the hollow space S1 and the outside due to the pressure change of the hollow space S2 based on the heating and cooling of the semiconductor device 1 and the static pressure change of the hollow space S1 and the outer space based on the altitude difference and the like. When there is a difference in static pressure between the spaces, gas enters and exits between the hollow portion S2 and the hollow space S1 and the outer space through the communication hole 19, so that the static pressure in the hollow portion S2 is hollow. It is almost equivalent to the static pressure in space S1 and outer space. Therefore, it is possible to prevent the diaphragm 9a from being deformed due to the difference in static pressure between the hollow portion S2 and the hollow space S1 or the outer space, so that the vibration characteristics of the diaphragm 9a are surely prevented from changing. be able to. Further, even when a pressure fluctuation such as sound reaches the diaphragm 9a and a dynamic pressure difference is generated between the hollow space S1 or the outer space and the hollow portion S2 based on this, the communication hole 19 is used. Since the ingress and egress of gas is blocked, the diaphragm 9a can be vibrated with high accuracy in response to the pressure fluctuation.

Further, the communication hole 19 can be easily formed in the spacer 51 simply by sandwiching the first film layer 23 having the slit-shaped notch 33 formed between the base substrate 21 and the second film layer 25. In particular, by forming the notch 33 by etching when manufacturing the spacer 5, the width of the notch 33 can be adjusted with high accuracy, so that a fine communication hole 19 having a small width can be easily formed. Can be done. In addition to this, by selecting the first film layer 23 having a small thickness dimension, a fine communication hole 19 having a small cross-sectional area can be formed. That is, as compared with the case where a similar communication hole 19 is formed in the circuit board 3, a fine communication hole 19 that restricts the ingress and egress of gas between the hollow portion S2 and the hollow space S1 and the outer space is provided in the spacer 5. It can be easily formed.

In the above-described embodiment, the holes 27 of the base substrate 21 forming the through holes 17 of the spacer 5 are formed in advance before the first thin film forming step, but the present invention is not limited to this, for example. , It may be formed at the same time as the holes 29 of the first film layer 23 by etching. However, in this case, it is preferable that the base substrate 21 is also formed from a material that can be etched. Further, although the upper end wall portion 13 and the side wall portion 15 constituting the lid body portion 11 are formed by separate members, the present invention is not limited to this, and for example, they may be integrally formed. In the case of this configuration, the spacer 5, the IC 7, and the semiconductor chip 9 may be arranged on the surface 3a of the circuit board 3, and then the lid portion 11 may be fixed to the circuit board 3.

Further, the spacer 5 and the semiconductor chip 9 are bonded, or the circuit board 3 and the spacer 5 are bonded after the adhesives 16 and 18 are adhered to the surface 5a of the spacer 5 and the surface 3a of the circuit board 3. However, it is not limited to this. That is, for example, as shown in FIG. 12, the adhesive sheets 41 and 43 are attached to the front surface 5a and the back surface 5b of the spacer 5 in advance, respectively, and the spacer 5 and the semiconductor chip 9 and the circuit board 3 are attached by these adhesive sheets 41 and 43, respectively. It does not matter if it adheres to. Further, the adhesive sheet may be attached to the circuit board 3 side first.

Further, it is assumed that two communication holes 19 are formed in the spacer 5, but the present invention is not limited to this. For example, as shown in FIG. 13, only one communication hole 19 may be formed, and 3 It does not matter if one or more are formed. Further, the spacer 5 may be formed elastically deformable by rubber or the like. Further, for example, at least one of the base substrate 21, the first film layer 23, and the second film layer 25 constituting the spacer 5 may be formed of an elastically deformable material. In the case of this configuration, even if the circuit board 3 vibrates, the vibration can be absorbed by the elastic force of the spacer 5, so that the diaphragm 9a can be prevented from vibrating due to the vibration of the circuit board 3. That is, it is possible to prevent the vibration of the circuit board 3 from being detected as noise in the diaphragm 9a, and it is possible to detect only the pressure fluctuation such as sound with higher accuracy.

Further, in the case of this configuration, when the spacer 5 and the circuit board 3 are fixed by the adhesives 16, 18 and the adhesive sheets 41, 43, the adhesives 16, 18 and the adhesive sheets 41, 43 are cured. Although it shrinks, the shrinkage of the adhesives 16, 18 and the adhesive sheets 41, 43 is alleviated by the elastic force of the spacer 5. Therefore, it is possible to prevent stress from being generated in the diaphragm 9a of the semiconductor chip 9 based on this contraction, and to prevent the vibration characteristics of the diaphragm 9a from changing.

Further, the spacer 5 may have a coefficient of thermal expansion that is the same as or close to that of the semiconductor chip 9. In this configuration, no stress is generated in the diaphragm 9a even if the spacer 5 and the semiconductor chip 9 are heated or cooled. When the circuit board 3 and the spacer 5 have significantly different coefficients of thermal expansion, the semiconductor device 1 is heated or cooled, and the circuit board 3 and the spacer 5 are heated or cooled based on the difference in the coefficients of thermal expansion described above. A stress is generated between the spacer 5 and the spacer 5, and this stress can be relieved at the spacer 5. Therefore, it is possible to prevent stress from being generated in the diaphragm 9a and changing its vibration characteristics.

Examples of the material of the spacer 5 described above include copper tungsten (80W-20Cu, 70W-30Cu), copper molybdenum (85Mo-15Cu), tungsten, molybdenum, alumina ceramics (Al2O3), silica ceramics (SiO2), and silicon. Carbide ceramics (SiC), tantalum, molybdenum, etc. are used. Further, a silicon substrate can be used as the substrate constituting the semiconductor chip 9. For example, the coefficients of thermal expansion of copper tungsten (70W-30Cu) and the silicon substrate are 10.2 ppm / ° C and 3.0 ppm / ° C, respectively, and the difference between the coefficients of thermal expansion is 7.2 ppm / ° C. That is, it is desirable to select a material such that the difference between the coefficient of thermal expansion of the spacer 5 and the semiconductor chip 9 is 7.2 ppm / ° C or less.

Further, the spacer 5 is configured by sequentially laminating the base substrate 21, the first film layer 23, and the second film layer 25, but the present invention is not limited to this, and at least the through holes 17 and the communication holes 19 are formed. Is formed, that is, it may be formed from one member. Further, the spacer 5 is provided with the communication hole 19, but the spacer 5 is not limited to this, and at least allows the flow of gas based on the static pressure difference between the hollow space S1 and the hollow portion S2 and acts on the diaphragm. It may be formed so as to block the passage of gas based on pressure fluctuations.

That is, the spacer 5 may be formed from, for example, a porous body. In the case of this configuration, the porous body may be formed so as to promote the inflow and outflow of gas between the hollow space S1 and the hollow portion S2 under the above-mentioned conditions through the gaps between the porous bodies. Even in this configuration, the same effect as when the communication hole 19 is formed in the spacer 5 can be obtained. As described above, the spacer may be made of a porous body, may be formed of an elastically deformable material such as a sponge, or may be formed of a material having the same or close coefficient of thermal expansion as that of a semiconductor chip. May be done.

(Example 2) Further, the spacer 5 is not limited to the above-mentioned structure. For example, as shown in FIG. 14, in addition to the base substrate 21, the first film layer 23, and the second film layer 25 similar to those in the above embodiment, the third film layer 51 covers the entire back surface 21b of the base substrate 21. May be provided to form the spacer 52, and the opening of the through hole 17 may be closed by the third film layer 51. Here, the third film layer 51 is formed of the same dry film as the first film layer 23 and the second film layer 25. The dry film constituting the third film layer 51 enters the holes 27 and the recesses opened in the back surface 21b of the base substrate 21, and is bonded to the base substrate 21 by adhesive. In the spacer 52 having this configuration, unlike the spacer 5 of the above embodiment, it is not necessary to fix the spacer 52 to the surface 3a of the circuit board 3 via an adhesive 16 such as silver paste, so that the adhesive 16 is formed in the through hole 17. It is possible to prevent the volume change of the cavity S2 caused by entering.

(Example 3) Further, it is said that the notch 33 forming the communication hole 19 is formed in the first film layer 23 sandwiched between the base substrate 21 and the second film layer 25. For example, as shown in FIG. 15, it may be formed on the third film layer 51. That is, the third film layer 51 is formed with a slit-shaped notch 53 along the back surface 21b of the base substrate 21. Then, by fixing the spacer 54 to the surface 3a of the circuit board 3 so that the back surface 51b of the third film layer 51 faces the surface 3a of the circuit board 3, these notches 53 and the surface 3a of the circuit board 3 The communication hole 55 similar to the above embodiment can be configured. However, in the case of this configuration, it is preferable to fix the spacer 54 to the surface 3a of the circuit board 3 with the sheet-like adhesive 56 instead of the paste-like adhesive 16 such as silver paste as in the above embodiment. That is, when the above fixing is performed with the paste-like adhesive 16, the notch 53 may be filled with the adhesive 16, but when the fixing is performed with the sheet-like adhesive 56, the notch 53 may be filled as described above. This is because it becomes difficult to fill. In the case of this configuration, only one film layer having no notch is formed on the surface 21a of the base substrate 21, for example, only the second film layer 25 similar to the above embodiment is formed. Just do it.

(Example 4) Further, the base member 21 is formed by forming holes 27 having a substantially circular shape in a plan view, but the present invention is not limited to this, and for example, as shown in FIG. 16, the base substrate 21 is formed. By forming the inner side of the large-diameter hole 57 having a substantially circular shape in a plan view in a mesh shape, a large number of minute holes 58 penetrating in the thickness direction of the base substrate 21 may be formed. I do not care. In the case of this configuration, since the tenting reinforcement of the base substrate 21 is performed by forming a part of the base substrate 21 in a mesh shape, as compared with the case of forming the holes 27 as in the above embodiment, The rigidity of the base substrate 21 can be improved, and the structure of the entire spacer 59 can be strengthened.

(Example 5) Further, it is assumed that holes 27 and minute holes 58 are formed in the base substrate 21, but the present invention is not limited to this. For example, as shown in FIG. 17, the holes 27 and the above holes 27 are formed in the base substrate 61. The base substrate 61 may be formed so as not to form the micropores 58, that is, to close the opening of the hole 29 of the first film layer 23. However, in the case of this configuration, the thickness dimensions of the two film layers 23,25 and the holes 29,31 formed in each film layer 23,25 are required so that a sufficiently large cavity S2 can be secured. It is preferable to increase the diameter of the film. In this configuration, unlike the above-described embodiment, it is not necessary to form the holes 27 and the minute holes 58 described in the above-described embodiment on the base substrate 61, so that the spacer 63 can be easily manufactured and the spacer 63 can be manufactured. The overall structure can be strengthened. Further, since the surface is not uneven after the film layers 23 and 25 are laminated on the base substrate 61, the photolithography and the etching process are facilitated.

(Example 6) Further, in the above embodiment, the semiconductor chip 9 is arranged on the surface 5a of the spacer 5, but the present invention is not limited to this, and for example, as shown in FIG. 18, the surface thereof is on the spacer 5. An engaging recess 45 recessed from 5a may be formed, and the semiconductor chip 9 may be engaged with and attached to the engaging recess 45. The engaging recess 45 is not limited to being integrally formed with the second film layer 25. For example, as shown in FIG. 19, a positioning layer 71 is formed on the surface 25a of the second film layer 25, and a positioning hole 73 larger than the second film layer 25 is formed on the positioning layer 71. The engaging recess 75 may be formed by the surface 25a of the film layer 25 and the positioning hole 73.

In the case of these configurations, when the semiconductor device 1 is manufactured, the semiconductor chip 9 can be easily positioned with respect to the spacer 5, so that the manufacturing efficiency of the semiconductor device 1 can be improved and the spacer 5 and the semiconductor chip can be manufactured. It is possible to improve the yield of 9. The configurations of the engaging recesses 45 and 75 can be applied not only to the spacers 5 shown in FIGS. 1 to 13 but also to the spacers 52, 54, 59 and 63 shown in FIGS. 14 to 17.

Further, the holes 27, 29, 31 and the large-diameter holes 57 formed in the base substrate 21, the first film layer 23, and the second film layer 25 are said to be formed in a substantially circular shape in a plan view. The present invention is not limited to this, and at least it may be formed so as to penetrate the base substrate 21, the first film layer 23, and the second film layer 25 in the thickness direction. Therefore, the holes 27, 29, 31 and the large-diameter holes 57 may be formed in a substantially rectangular shape, a polygonal shape, an elliptical shape, or the like in a plan view, for example. Further, all the spacers 5,52,54,59,63 described above are arranged on the surface 3a of the circuit board 3, but the present invention is not limited to this, and for example, on the surface of the package in which the circuit is incorporated. It may be arranged. That is, the semiconductor device may be configured by using the above package instead of the circuit board 3. Further, the semiconductor chip 9 is composed of a sound pressure sensor chip provided with a diaphragm 9a, but the present invention is not limited to this, and at least a movable portion such as the diaphragm 9a constituting the semiconductor chip 9 may be provided. Therefore, the semiconductor chip may be, for example, a pressure sensor chip that measures the pressure or pressure change in the outer space of the semiconductor device 1.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within a range not deviating from the gist of the present invention are also included.

<figref num="1">It is a side sectional view which shows the semiconductor device which concerns on one Embodiment of this invention.</figref><figref num="2">It is a top view which shows the spacer in the semiconductor device of FIG.</figref><figref num="3">FIG. 2 is a cross-sectional view taken along the line AA in FIG.</figref><figref num="4">FIG. 2 is a cross-sectional view taken along the line BB in FIG.</figref><figref num="5">It is a top view which shows the base substrate used for the spacer shown in FIG.</figref><figref num="6">FIG. 5 is a cross-sectional view taken along the line CC of FIG.</figref><figref num="7">It is a top view which shows the state which formed the 1st film layer on the surface of the base substrate shown in FIG.</figref><figref num="8">It is a cross-sectional view taken along the line DD of FIG.</figref><figref num="9">It is EE arrow cross-sectional view of FIG.</figref><figref num="10">It is a side sectional view which shows the manufacturing method of the semiconductor device of FIG.</figref><figref num="11">It is a side sectional view which shows the manufacturing method of the semiconductor device of FIG.</figref><figref num="12">It is a side sectional view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref><figref num="13">It is a top view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref><figref num="14">It is a side sectional view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref><figref num="15">It is a side sectional view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref><figref num="16">It is a side sectional view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref><figref num="17">It is a side sectional view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref><figref num="18">It is a side sectional view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref><figref num="19">It is a side sectional view which shows the spacer used for the semiconductor device which concerns on other embodiment of this invention.</figref>

Code description

1 ... Semiconductor device, 3 ... Circuit board, 3a ... Surface, 5,52,54,59,63 ... Spacer, 5a ... Surface, 9 ... Semiconductor chip, 9a ... Diaphragm, 17 Through hole, 19,55 Communication hole, 21 Base substrate, 21a Surface, 23 First film layer, 23a Surface, 25 Second film layer, 25b back surface, 33,53 notch, 45 engaging recess, S1 hollow space (outer space), S2 hollow part