Separating apparatus and processing method for plate member

Separation equipment and processing method of plate

<p>10. . . First substrate</p><p>10'. . . First substrate</p><p>11. . . Single crystal silicon substrate</p><p>12. . . Separation layer</p><p>12"... porous layer</p><p>13. . . Non-porous layer</p><p>13'. . . Active area</p><p>14. . . Insulation</p><p>20. . . Second base</p><p>50. . . Bonded substrate stack</p><p>51. . . Recess</p><p>54. . . Component isolation area</p><p>55. . . Gate electrode</p><p>56. . . Gate insulating film</p><p>59. . . Sidewall</p><p>60. . . Metal silicide layer</p><p>61. . . Insulating film</p><p>62. . . Barrier metal</p><p>63. . . conductor</p><p>100. . . Separation equipment</p><p>101. . . motor</p><p>102. . . Coupler</p><p>103. . . Axis of rotation</p><p>104. . . Bearing</p><p>105. . . Upper substrate holding part</p><p>106. . . Lower substrate holding part</p><p>107. . . Bearing</p><p>108. . . Axis of rotation</p><p>109. . . Coupler</p><p>110. . . cylinder</p><p>113. . . On the pedestal</p><p>114. . . Lower pedestal</p><p>120. . . nozzle</p><p>121. . . high-pressure hose</p><p>123. . . valve</p><p>124. . . High pressure pipe</p><p>140. . . Position adjustment mechanism</p><p>141. . . The first adjustment mechanism</p><p>142. . . Second adjustment agency</p><p>150. . . Measuring device</p><p>160. . . Controller</p><p>200. . . Servo Drive Pump</p><p>210. . . pressure gauge</p>

The drawings incorporated and constituting part of the specification show embodiments of the present invention, and together with the following description, the principles of the present invention can be explained.

1A to 1E are schematic diagrams for explaining the steps of forming a porous layer in a substrate manufacturing method according to a preferred embodiment of the present invention.

Fig. 2 is a diagram showing the configuration of the separation device of the preferred embodiment of the present invention.

Figure 3 is a graph showing an example of the measurement results obtained by the measurement device.

FIG. 4 is a graph showing the vertical position of the nozzle, where the nozzle is driven by a position adjustment mechanism according to the measurement result shown in FIG. 3.

Fig. 5 is a graph showing a state in which the position of the surrounding part of the bonded substrate stack is measured by the measuring device.

Fig. 6 is a graph showing a state in which the position of the surrounding part of the bonded substrate stack is measured by the measuring device.

Fig. 7 is a graph showing a state in which the bonded substrate stack is separated.

Fig. 8 is a graph showing a state in which the bonded substrate stack is separated.

Figure 9 is an enlarged view of the nozzle and bonding substrate stack (peripheral part).

Fig. 10 is a graph showing a state in which the bonded substrate stack is separated. The vertical movement of the substrate holding portion (bonded substrate stack) is synchronized with its rotation.

FIG. 11 is a graph showing an example of a position adjustment mechanism. The position adjustment mechanism includes a mechanism for adjusting the elevation angle and position of the nozzle.

12A to 12D are cross-sectional views showing a method of manufacturing a semiconductor device using a semiconductor substrate, wherein the semiconductor substrate is manufactured using the substrate manufacturing method of the preferred embodiment of the present invention.

Fig. 13 is a graph showing a state in which a bonding substrate with a large distortion is stacked at a porous layer and separated into two substrates.

Field of invention

The present invention relates to separation equipment and processing methods for bonding substrate stacks and other plates, semiconductor substrate manufacturing methods, and semiconductor device manufacturing methods.

Background of the invention

A substrate with an SOI (Silicon On Insulator) structure is known as a substrate with a single crystal silicon layer on an insulating layer. Devices using this SOI substrate have many advantages that cannot be achieved with ordinary silicon substrates. Examples of these advantages are as follows:

(1) Since dielectric isolation is prone to occur, the degree of integration can be increased.

(2) Radiation resistance can be increased.

(3) Since the stray capacitance is small, the operating speed of the device can be increased.

(4) No additional steps are required.

(5) Locking can be prevented.

(6) A complete depletion type field effect transistor can be formed by a thin film forming method.

Since the SOI structure has the above-mentioned different advantages, many researches have been done on its forming method in the past few decades.

As one of the methods, an SOI structure can be formed by bonding a single crystal silicon substrate to another thermally oxidized single crystal silicon substrate by annealing or an adhesive. In this method, an active layer used to form the device must be very uniformly thin. More specifically, a single crystal silicon substrate with a thickness of several hundred microns must be thinned below the micron level.

In order to thin the substrate, polishing or selective etching can be used.

The single crystal silicon substrate is difficult to be thinned uniformly by polishing. Especially when thinning to levels below micrometers, the range of change is between tens of percent. This difficulty will become more significant when the wafer size becomes larger.

The present invention has disclosed a new SOI technology in the Japanese Prior Published Application No. 521338. In this technique, a first substrate formed from a porous layer on a single crystal silicon substrate and a non-porous single crystal layer on its surface is bonded to a second substrate via an insulating layer. After that, the bonded substrate stack is separated into two substrates at the porous layer, thereby transferring the non-porous single crystal layer to the second substrate. This technology has the following advantages. Because the thickness uniformity of the SOI layer is very good, it can reduce the density of crystal defects in the SOI layer, and the surface flatness of the SOI layer will also be very good. It does not require expensive manufacturing equipment with special specifications. And a single manufacturing equipment can be used to manufacture SOI substrates with a thickness of about several hundred angstroms to 10 μm.

In order to separate the first and second substrates into two substrates without damaging the first and second substrates, the following method can be used: the two substrates are pulled in opposite directions and applied in the direction perpendicular to the bonding interface A force; applying a shear force parallel to the bonding interface (for example, the two substrates will move parallel in opposite directions in a plane parallel to the bonding interface, or the two substrates will rotate in opposite directions and apply in the circumferential direction One force); apply pressure in the direction perpendicular to the bonding interface; apply wave energy such as ultrasonic waves to this separation area; insert a peeling member (such as a sharp blade like a knife) from the side surface of the bonded substrate stack into parallel In the separation area of the bonding interface; the expansion energy of the substrate is used to fill the pores of the porous layer as the separation area; the porous layer as the separation area is thermally oxidized from the side surface of the bonded substrate stack to make the expansion porous The volume of the layer separates these substrates; and the porous layer as the separation area is selectively etched from the side surface of the bonded substrate stack to separate the substrates.

As a method of separating a bonded substrate stack, the applicant disclosed an epoch-making technology in Japanese Prior Patent Application No. 11-45840 (ie, Japanese Patent No. 2877800). In the separation method disclosed in this Japanese Prior Patent Application No. 11-45840, one of a porous layer or ion implantation layer as a separation layer is bonded to the substrate stack by injecting liquid to the side surface of the bonded substrate. Inside and separated into two bases.

More specifically, in the separation method disclosed in Japanese Prior Patent Application No. 11-45840, the bonded substrate stack is fixed by a pair of holders (substrate holding parts). The substrate stack is smaller in size. When the bonding substrate stack is rotating, a fluid is injected into the side surface of the bonding substrate stack, thereby separating the bonding substrate stack into two substrates at the porous layer.

When the pair of holders are used to hold the bonded substrate stack, the holder has a smaller size than the bonded substrate stack. Due to its own weight, the surrounding parts may be twisted, or the bonded substrate stack may have some distortion. These distortions have been produced during the manufacturing process and have not been corrected. It is assumed that there is distortion in the bonding substrate stack held in the holder. In this case, when the bonding substrate stack is rotating, a fluid is injected around it, and this fluid can be injected to a position that deviates from an appropriate position (for example, the bonding interface or the separation layer).

For ease of understanding, an extreme situation will be explained. For example, if the bonded substrate stack is greatly twisted, assuming that the bonded substrate stack is not twisted and the position of the fluid injected from the nozzle has been adjusted, the fluid will not be injected into the separation layer or the bonding interface of the bonded substrate stack. When this happens, the separation step cannot be performed. This phenomenon will be explained with reference to FIG. 13, which shows a state in which the bonded substrate stack 50 that is greatly distorted is separated into two substrates at the separation layer 12. In the example shown in FIG. 13, the position of the real porous separation layer 12 is greatly deviated from the position of the porous layer without distortion (the ideal position of the porous layer). In this case, if the porous layer 12 is arranged at an ideal position, the position of the nozzle 120 can be adjusted. When the separation is performed in this state, the fluid from the nozzle 120 will not be injected into the separation layer 12, thereby preventing smooth separation. If a large distortion occurs around the bonded substrate stack 50, separation will not occur quickly. This will produce bad separation.

Since the size of the bonded substrate stack will increase with the size of the required SOI substrate, the possibility of the above-mentioned poor separation will become higher and higher.

In addition, when the bonded substrate stack is held by the holder, some foreign substances will enter between the bonded substrate stack and the holder. In this inert shape, the fluid from the nozzle can be injected into a position away from the porous layer or the bonding interface of the bonding substrate stack.

Summary of the invention

In view of the above situation, the present invention is produced, and the purpose of the present invention is to ensure that the fluid can be injected into the proper position of the plate when the plate is separated.

According to a first aspect of the present invention, there is provided a separation method using a fluid separation member, which includes moving at least one of a member and a spouting portion in accordance with the amount of twisting of the surrounding portion of the member, the member having a concave portion on the surrounding side of the member There is a separation layer on the inner side, so that the fluid ejected from the ejection portion will hit the recessed portion.

According to a preferred aspect of the present invention, the member is preferably an adhesive member obtained by bonding an insulating layer, a first substrate, and a second substrate, wherein the first substrate has a non-porous layer on the separation layer Single crystal silicon layer.

According to a preferred aspect of the present invention, the amount of distortion around the member is preferably measured before or when the fluid is ejected.

According to a second aspect of the present invention, a separation device is provided for separating plates with a separation layer at the separation layer. The separation device includes a holding portion holding the plate and a spraying portion for ejecting fluid so as to separate the plates by the holding A measuring device for measuring the position of the surrounding part of the board held by the holding part, and a driving part for dynamically driving the holding part and the ejection part according to the measurement result obtained by the measuring device At least one, during the separation of the plate held by the holding part, the fluid ejected from the ejection part will be injected into a recess on the peripheral side of the plate held by the holding part.

According to a preferred aspect of the present invention, the driving part can preferably dynamically drive at least one of the holding part and the ejection part according to the result obtained by the measuring device, so that the fluid ejected from the ejection part is injected into the bonding interface of the plate. The bonding interface is a recess located on the peripheral side surface, or enters the separation layer through the recess.

According to a preferred aspect of the present invention, the measuring device is preferably capable of measuring the position of the peripheral part of the plate held by the holding part in a direction perpendicular to the separation layer. The driving part preferably has a mechanism for dynamically driving at least one of the holding part and the ejection part in the direction perpendicular to the separation layer according to the measurement result obtained by the measuring device during the separation of the plate held by the holding part .

According to a preferred aspect of the present invention, the driving part preferably has a mechanism for dynamically changing the direction of the ejection part according to the measurement result obtained by the measuring device during the separation of the plate held by the holding part.

According to a preferred form of the present invention, the device preferably further includes a rotating mechanism for rotating the holding portion capable of holding the plate so as to rotate the plate around an axis perpendicular to the separation layer, and is held by the holding portion During the separation of the plate, when the fluid is ejected from the ejection part, the fluid will be injected into the plate through the surrounding of the plate by the rotating plate.

According to a preferred aspect of the present invention, it is preferable that the measuring device can measure the position of the peripheral portion of the plate rotated by the rotating mechanism over the entire circumference of the plate.

According to a preferred aspect of the present invention, after the plate is held by the holding portion and before the plate starts to separate, the measuring device preferably can measure the position of the surrounding portion of the plate held by the holding portion.

According to a preferred form of the present invention, the position of the peripheral part of the plate measured by the measuring device and the separation of the plate are preferably performed simultaneously, and the driving part is based on the measurement results successively from the measuring device when the plates are separated, At least one of the holding part and the ejection part is dynamically driven.

According to a preferred aspect of the present invention, the width of the fluid to be ejected from the ejection portion is preferably 1/20 to 1/2 of the width of the recessed portion.

According to a preferred aspect of the present invention, the plate to be separated preferably has a disc shape.

According to a preferred aspect of the present invention, the holding portion can preferably hold the plate to be separated horizontally.

According to a preferred aspect of the present invention, the separation layer is preferably a layer formed by anodization.

According to a preferred aspect of the present invention, the separation layer is preferably a layer formed by ion implantation.

According to a third aspect of the present invention, there is provided a processing method for processing a plate with a separation layer. The processing method includes the following steps: a holding step, holding the plate by the holding portion; and a measuring step, for measuring the The position of the peripheral part of the plate held by the holding part and the separation step are used to eject a fluid from the ejection part, and the fluid is used to separate the plate held by the holding part at the separation layer, wherein in the separation step At least one of the holding part and the ejection part is dynamically driven according to the measurement result obtained in the measurement step, so that the fluid ejected from the ejection part will be injected into a concave part, which is located around one of the plates held by the holding part On the side surface.

According to a preferred aspect of the present invention, in the separation step, at least one of the holding portion and the ejection portion is dynamically driven according to the measurement result obtained in the measurement step, so that the fluid ejected from the ejection portion is injected into a plate of a plate. In the bonding interface, the bonding interface is located in a recess on the peripheral side surface, or injected into the separation layer through the recess.

According to a preferred aspect of the present invention, in the measuring step, it is preferable to measure the position of the peripheral part of the plate held by the holding part in the direction perpendicular to the separation layer.

According to a preferred aspect of the present invention, in the separation step, at least one of the holding portion and the ejection portion is dynamically driven in a direction perpendicular to the separation layer according to the measurement result obtained in the measurement step.

According to a preferred aspect of the present invention, in the separation step, it is preferable that the direction of the ejection portion can be dynamically changed according to the measurement result obtained in the measurement step.

According to a preferred aspect of the present invention, in the separation step, when the plate is rotated around an axis perpendicular to the separation layer, it is preferable to separate the plate held by the holding portion so that the fluid ejected from the ejection portion can be It is injected into the board through its surroundings.

According to a preferred aspect of the present invention, in the measuring step, when the plate is rotated around an axis perpendicular to the separation layer, it is preferable to measure the circumference of the plate held by the holding portion on the entire circumference of the plate The location of the department.

According to a preferred aspect of the present invention, the separation step is preferably performed after the measurement step.

According to a preferred aspect of the present invention, the separation step is preferably performed simultaneously with the measurement step.

According to a preferred aspect of the present invention, the width of the fluid ejected from the ejection portion is preferably 1/20 to 1/2 of the recessed portion.

According to a preferred aspect of the present invention, the plate to be separated preferably has a disc shape.

According to a preferred aspect of the present invention, the holding portion can preferably hold the plate to be separated horizontally.

According to a preferred aspect of the present invention, the separation layer is preferably a layer formed by anodization.

According to a preferred aspect of the present invention, the separation layer is preferably a layer formed by ion implantation.

According to the fourth aspect of the present invention, a semiconductor substrate manufacturing method is provided. The method includes the following steps: forming an adhesive substrate stack as a plate, and the formation method is by having a separation layer inside and on the separation layer The first substrate of a transfer layer is adhered to the second substrate, and the adhered substrate stack is separated at the separation layer using the processing method of the third aspect of the present invention described above.

According to the fifth aspect of the present invention, a semiconductor device manufacturing method is provided, including the following steps: using the fourth aspect of the manufacturing method of the present invention to prepare an SOI substrate, the SOI layer of the SOI substrate is device-isolated, and the device is isolated here A transistor is formed on the over SOI layer.

This transistor can be a partially depleted field effect transistor (FET) or a fully depleted FET.

Other features and advantages of the present invention can be clearly understood from the following description accompanying the drawings. In the entire figure, the same or similar parts will be represented by similar parameters.

Schematic description

The drawings incorporated and constituting part of the specification show embodiments of the present invention, and together with the following description, the principles of the present invention can be explained.

1A to 1E are schematic diagrams for explaining the steps of forming a porous layer in a substrate manufacturing method according to a preferred embodiment of the present invention.

Fig. 2 is a diagram showing the configuration of the separation device of the preferred embodiment of the present invention.

Figure 3 is a graph showing an example of the measurement results obtained by the measurement device.

FIG. 4 is a graph showing the vertical position of the nozzle, where the nozzle is driven by a position adjustment mechanism according to the measurement result shown in FIG. 3.

Fig. 5 is a graph showing a state in which the position of the surrounding part of the bonded substrate stack is measured by the measuring device.

Fig. 6 is a graph showing a state in which the position of the surrounding part of the bonded substrate stack is measured by the measuring device.

Fig. 7 is a graph showing a state in which the bonded substrate stack is separated.

Fig. 8 is a graph showing a state in which the bonded substrate stack is separated.

Figure 9 is an enlarged view of the nozzle and bonding substrate stack (peripheral part).

Fig. 10 is a graph showing a state in which the bonded substrate stack is separated. The vertical movement of the substrate holding portion (bonded substrate stack) is synchronized with its rotation.

FIG. 11 is a graph showing an example of a position adjustment mechanism. The position adjustment mechanism includes a mechanism for adjusting the elevation angle and position of the nozzle.

12A to 12D are cross-sectional views showing a method of manufacturing a semiconductor device using a semiconductor substrate, wherein the semiconductor substrate is manufactured using the substrate manufacturing method of the preferred embodiment of the present invention.

Fig. 13 is a graph showing a state in which a bonding substrate with a large distortion is stacked at a porous layer and separated into two substrates.

Symbol description of main components

10. . . First substrate

10'. . . First substrate

11. . . Single crystal silicon substrate

12. . . Separation layer

12"... porous layer

13. . . Non-porous layer

13'. . . Active area

14. . . Insulation

20. . . Second base

50. . . Bonded substrate stack

51. . . Recess

54. . . Component isolation area

55. . . Gate electrode

56. . . Gate insulating film

59. . . Sidewall

60. . . Metal silicide layer

61. . . Insulating film

62. . . Barrier metal

63. . . conductor

100. . . Separation equipment

101. . . motor

102. . . Coupler

103. . . Axis of rotation

104. . . Bearing

105. . . Upper substrate holding part

106. . . Lower substrate holding part

107. . . Bearing

108. . . Axis of rotation

109. . . Coupler

110. . . cylinder

113. . . On the pedestal

114. . . Lower pedestal

120. . . nozzle

121. . . high-pressure hose

123. . . valve

124. . . High pressure pipe

140. . . Position adjustment mechanism

141. . . The first adjustment mechanism

142. . . Second adjustment agency

150. . . Measuring device

160. . . Controller

200. . . Servo Drive Pump

210. . . pressure gauge

Detailed description of the preferred embodiment

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1A to 1E are schematic diagrams for explaining a method of manufacturing a substrate having, for example, the SOI structure of the preferred embodiment of the present invention.

In the step shown in FIG. 1A, a single crystal silicon substrate 11 is prepared to form a first substrate (seed wafer), and a porous silicon layer 12 as a separation layer is formed on the single crystal silicon layer 11 Mainly on the surface. The porous silicon layer 12 can be produced by anodizing the single crystal silicon substrate 11 in an electrolyte solution (anodizing solution).

As the electrolyte solution, for example, a solution of hydrogen fluoride, a solution of hydrogen fluoride and ethanol, and a solution of hydrogen fluoride and isopropanol can be used. More specifically, as the electrolyte solution, for example, a solution containing an HF aqueous solution (with an HF concentration of 49%) and ethanol mixed in a ratio of 2:1 by volume can be used.

The porous silicon layer 12 may have a multilayer structure, including at least two layers with different porosities. The porous silicon layer 12 having a multilayer structure preferably includes a first porous silicon layer having a first porosity on the surface side, and a second porous silicon layer is included under the first porous silicon layer, It has a second porosity higher than the first porosity. With such a multilayer structure, a defect-free non-porous layer 13 can be formed on the first porous silicon layer in the step of forming the non-porous layer 13 later, and a bonding substrate stack can be used in the separation step Separate at the desired location. The first porosity is preferably 10% to 30%, more preferably 15% to 25%. The second porosity is preferably 35% to 70%, more preferably 40% to 60%.

When the above solution mixture (49% by weight concentration of hydrofluoric acid: ethanol = 2:1) is used as an electrolyte solution, it is best that the first layer (surface side) is at 8mA/cm ² 5 to 11 minutes at a current density of 5 to 11 minutes, and the second layer (inner surface side) is at 23 to 33mA/cm ² The current density is 80 seconds to 2 minutes.

Secondly, it is better to perform at least one of the following steps (1) to (4). Preferably, steps (1) and (2) are executed in the order. It is better to perform steps (1), (2) and (3) or (1), (2) and (4) in the order, and it is best to perform steps (1), (2), (3) and ( 4) The order of execution.

(1) Forming a protective film on the porous wall in the porous silicon layer (pre-oxidation step) In this step, a protective film such as an oxide film or a nitride film is formed on the porous wall in the porous silicon layer 12. This prevents any increase in pore size due to subsequent annealing. The protective film can be formed by annealing in oxygen (preferably at 200°C to 700°C, preferably 300°C to 500°C). After that, it is better to remove the oxide film formed on the surface of the porous silicon layer 12, and the above removal can be achieved by exposing the surface of the porous silicon layer 12 to a solution containing hydrofluoric acid.

(2) Hydrogen baking step (pre-baking step) In this step, the first substrate 10 on which the porous silicon layer 12 is formed can be annealed in a reducing gas containing hydrogen at a temperature between 800°C and 1200°C. By this annealing, the holes on the surface of the porous silicon layer 12 can be sealed to a certain extent. If there is a naturally formed oxide film on the surface of the porous silicon layer 12, it can be removed.

(3) Micro-material supply step (pre-injection step) When the non-porous layer 13 is to be formed on the porous silicon layer 12, it is preferably formed at a low speed by supplying a small amount of raw material in the initial stage of formation. With such a production method, the movement of atoms on the surface of the porous silicon layer 12 can be proposed, and the pores on the surface of the porous silicon layer 12 can be sealed. More specifically, the supply of raw materials can be controlled so that the production rate becomes 20 nm/min or lower, preferably 10 nm/min or lower, and most preferably 2 nm/min or lower.

(4) High-temperature baking step (intermediate baking step) when annealing is performed under a reducing gas containing hydrogen at a temperature higher than the temperature in the hydrogen baking step and/or the trace material supply step, the porous silicon layer 12 can be cured. Further sealing and flattening.

In the first stage of the step shown in FIG. 1B, the first non-porous layer 13 is formed on the porous silicon layer 12. As the first non-porous layer 13, for example, a single crystal silicon layer, a polysilicon layer or an amorphous silicon layer, a Ge layer, a SiGe layer, a SiC layer, a C layer, a GaAs layer, a GaN layer, an AlGaAs layer, an InGaAs layer, InP Layer and InAs layer.

In the second stage of the step shown in FIG. 1B, the silicon dioxide layer (insulating layer) 14 as the second non-porous layer is formed on the first non-porous layer 13. In this way, the first substrate 10 is obtained, and the silicon dioxide layer can be formed in a hydrogen/oxygen gas at 1100° C. for 10 to 33 minutes.

In the step shown in FIG. 1C, a second substrate (handle wafer) 20 is prepared, and it is brought into close contact with the first substrate 10 at room temperature, so that the insulating layer 14 faces the second substrate 20, thereby A bonded substrate stack is formed.

The insulating layer 14 may be formed on the side of the single crystal silicon layer 13 or on the second substrate 20, or on both the single crystal silicon layer 13 and the second substrate 20, as long as the first and second substrates are in close contact with each other when the image can be obtained. The state shown in 1C is sufficient. However, when the insulating layer 14 is formed on the first non-porous layer (for example, the single crystal silicon layer) 13 as the active layer, as described above, it is interposed between the first substrate 10 and the second substrate The bonding interface between 20 can be separated from the active layer, and a high-quality semiconductor substrate, such as an SOI substrate, can be obtained.

After the substrates 10 and 20 have been in close contact, it is better to perform a process of strengthening the degree of knots between the substrates. Examples of this processing method may be: 1) annealing in nitrogen at 1100°C for 10 minutes; and 2) annealing and oxidation in hydrogen/oxygen gas at 1100°C for 50 to 100 minutes. In addition to this treatment method, anode bonding and/or compression can also be performed.

As the second substrate 20, a silicon substrate, a substrate obtained by forming a silicon dioxide layer on a silicon substrate, a transparent substrate formed of quartz, or a sapphire substrate can be used. However, any substrate with a sufficiently flat bonding surface can be used as the second substrate 20.

In the step shown in FIG. 1D, the bonding substrate stack 50 is separated from the fragile porous layer 12 with low mechanical strength using a separation method described later.

In the step shown in FIG. 1E, after separation, the porous layer 12" on the non-porous layer 13 is selectively removed by etching or the like.

Moreover, after the separation, the single crystal silicon substrate 11 on the separated first substrate 10 is selectively removed by etching or the like. The single crystal silicon substrate 11 obtained in this way can be reused as a substrate for forming the first substrate 10 or the second substrate 20.

As the bonding substrate stack, a substrate prepared by the following method can be used. First, prepare a semiconductor substrate, such as a single crystal silicon substrate such as a mirror wafer or an epitaxial wafer. An insulating film, such as a thermal silicon oxide film, is formed on the substrate. Secondly, for example, positive and negative hydrogen ions or rare gas ions are immersed in linear beam or plasma and implanted by ion implantation, thereby forming an extremely doped ion implantation layer at a predetermined depth on the surface for separation Floor. The first substrate was obtained in the above-mentioned manner.

Next, the second substrate is prepared according to the same procedure as described above, and is bonded to the first substrate according to the above bonding method. In this way, a bonded substrate stack can be obtained with a layer to be transferred (transfer layer) inside.

The ion implantation layer is distorted or contains defects or holes due to the micro-cavities formed by the implanted ions. Such an ion implantation layer has relatively low mechanical strength and therefore can be used as a separation layer.

The separation method and equipment according to a preferred embodiment of the present invention will be described below, which can be applied to the separation step shown in FIG. 1D. The separation device of the present invention can be used to separate an adhesive substrate stack at the separation layer into two substrates, and the adhesive substrate stack has a separation layer with a porous layer formed by anodization or ion implantation. Referring to FIG. 1D, the bonding substrate stack is separated inside the separation layer. However, the bonding substrate stack can also be separated between the porous layer 12 and the non-porous layer 13 and/or between the single crystal silicon substrate 11 and the porous layer 12. It is also possible to separate the bonding substrate stack near the interface between the porous layer 12 and the non-porous layer 13 by controlling the layer structure of the separation layer.

The separation device includes a spray part (nozzle) for spraying fluid and a substrate holder part for holding the plate. The separation device further includes a measuring device (such as a laser displacement meter) for measuring the position of the surrounding portion of the bonded substrate stack (also That is, the position perpendicular to the direction of the separation layer). In addition, the separation device further includes a driving part for dynamically driving at least one of the substrate holding part and the fluid ejection part according to the measurement result obtained by the measuring device during the separation of the bonded substrate stack. It should be noted that the peripheral part means a horizontal surface part near the inclined part of the wafer, and the peripheral part may mean a part not close to this inclined part or slightly close to the center. Generally, this separation is performed by rotating the bonded substrate stack around an axis that is perpendicular to the two surfaces or the separation layer of the bonded substrate stack while simultaneously injecting fluid into the side surface of the bonded substrate stack. During separation, the bonded substrate stack generally rotates one or more times to inject fluid into its side surfaces. The dynamic driving of at least one of the substrate holding part and the fluid ejecting part is performed synchronously with the rotation according to the above-mentioned measurement result. Preferably, the bonded substrate stack to be separated can have a recess on the periphery of its side surface. This recess can be formed by using a first substrate (seed wafer) and a second substrate (handling wafer) to fabricate a bonded substrate stack. Each of the first and second substrates uses a wafer with an inclined portion Has a circular cross-sectional shape.

Figure 2 is a diagram showing the configuration of the separation device of the present invention. The separating device 100 horizontally holds the bonded substrate stack 50 that is the plate to be separated, and when the bonded substrate stack rotates, it sprays fluid toward its recess, where a separation layer is exposed or has a separation layer inside. , Thereby separating the bonding substrate stack 50 from the porous layer (separation layer) into two substrates. It should be noted that the best fluid can be injected into the bonding interface. The injection of fluid into the interface enables the stress to act more effectively in order to separate the two wafers.

The bonded substrate stack 50 is held by a pair of substrate holding portions 105 and 106 having a common central axis. The bonded substrate stack 50 can also be held by a clamping mechanism between the pair of substrate holding parts 105 and 106, or clamped by the substrate holding parts 105 and 106 thereby.

The upper substrate holding portion 105 is connected to a motor 101 via a rotating shaft 103 and a coupling 102. The rotation speed of the motor 101 can be arbitrarily controlled by a controller 160. The rotating shaft 103 is connected to an upper pedestal 113 via a bearing 104. Supported axially.

The lower substrate holding portion 106 is connected to a cylinder 110 via a rotating shaft 108 and a coupling 109. Therefore, the lower substrate holding portion 106 is moved vertically by the cylinder 110. The cylinder 110 is driven to place the bonded substrate stack 50 in the separation device 100 and release the separated substrate from the separation device 100. This cylinder 110 can be driven to apply a pressing force or tension (when the bonded substrate stack is clamped) to the bonded substrate stack 50 during the separation process. The cylinder 110 is controlled by the controller 160, and the rotating shaft 108 is axially supported by the lower base 114 via a bearing 107.

A nozzle (ejection part) 120 for ejecting fluid is arranged on the lower base 114 in a direction parallel to the axial direction (vertical direction) of the bonded substrate stack 50 and/or parallel to the plane direction of the bonded substrate stack 50 ( Horizontal direction) adjust the position of the nozzle 120. In the separation step, the nozzle 120 is guided by the position adjustment mechanism 140 to the porous layer (recess) of the bonded substrate stack 50.

The nozzle 120 is connected to the outlet of the servo-driven pump 200 through a high-pressure hose 121, a valve 123 and a high-pressure pipe 124. The servo-driven pump 200 has a pressure gauge 210 for detecting the fluid pressure at the outlet. According to the output from the pressure gauge 210, the change in fluid pressure can be suppressed within a predetermined value (for example, within 10% of the target pressure).

A measuring device (including, for example, a laser displacement instrument) 150 is mounted on the lower pedestal 114 to measure the position of the periphery of the bonded substrate stack 50, which is held by the pair of substrate holding portions 105 and 106 It is held on the whole circumference. The measuring device can be arranged on the upper pedestal 113 or on other components that can measure the degree of deviation of the surrounding part from a reference value. In this embodiment, the measuring device measures the position (vertical position) of the surrounding part of the bonded substrate stack 50 with respect to the axial direction (vertical direction). In this embodiment, the bonded substrate stack 50 measures its entire surroundings while rotating. This rotation is driven by the rotational force generated by the motor 101. At this time, the bonded substrate stack 50 is formed by a pair of The substrate holding parts 105 and 106 are held.

After the bonded substrate stack 50 has been held by the substrate holding portions 105 and 106, the position of the bonded substrate stack can be measured by a measuring device (in this case, the bonded substrate stack 50 The vertical position) is generally performed before the bonding substrate stack 50 starts to separate. The measurement result obtained by the measuring device will be transmitted to the controller 160. When the bonding substrate stack 50 is actually separated, the controller 160 will be connected to the rotation of the bonding substrate stack 50 according to the measurement result obtained by the measuring device 150. The position adjusting mechanism 140 is driven synchronously, so that the fluid ejected from the nozzle 120 can always be injected into the concave portion of the bonding substrate stack 50 (preferably into the bonding interface). In this way, the fluid ejected from the nozzle 120 can promote the separation of the bonded substrate stack 50 to a limited extent. Even when the bonded substrate stack 50 has been twisted, or some foreign matter such as particles or dust is between the substrate holding portion and the bonded substrate stack 50, the bonded substrate stack 50 is held at a deviation from the ideal position. The substrate stack 50 can be separated with a good reproducibility. As described above, as the size of the bonding substrate stack 50 becomes larger, problems such as distortion of the bonding substrate stack 50 become obvious. According to the separation device of this embodiment, the bonded substrate stack 50 can be separated with good reproducibility regardless of its own size.

When the bonded substrate stack 50 rotates one or more times during separation, it is preferable that during the one or more rotations, the driving of the position adjustment mechanism 140 synchronized with the rotation of the bonded substrate stack 50 can continue. Only when the bonded substrate stack 50 rotates once, the position driving of the position adjusting mechanism 140 is performed. This is because after the surrounding portion of the bonded substrate stack 50 is separated, even when a pressure less than the separated surrounding portion 10 is applied (that is, only part of the fluid is injected into the porous layer), the bonded substrate stack 50 can still be easily separated.

Figure 3 is a graph showing the measurement results obtained by the measurement device. This measurement result provides that the vertical position of the periphery of the bonded substrate stack 50 is a function of the rotation angle (0° to 360°) of the bonded substrate stack 50. The example of FIG. 3 shows the offset of the surrounding part of the bonded substrate stack 50 with respect to a reference position (reference plane). The vertical position of the bonding interface of the bonded substrate stack 50 is in a state (ideal state) , Wherein the bonded substrate stack 50 is not twisted, and is properly held by the substrate holding portions 105 and 106. It should be noted that this reference position can be arbitrarily defined. For example, the reference position can be defined on the lower surface or the upper surface of the bonded substrate stack 50 in an ideal state. On the other hand, the reference position may be defined at a predetermined position of the substrate holding portion 105, 106 or other components.

FIG. 4 is a graph showing the vertical position of the nozzle 120, where the nozzle is driven by the position adjustment mechanism according to the measurement result shown in FIG. 3. The example shown in FIG. 4 uses the same measurement result as that in FIG. 3 as a parameter to obtain the vertical position of the nozzle 120.

As described above, in the separation device shown in FIG. 2, the axial position (vertical position) of the bonded substrate stack 50 is fixed, and the nozzle 120 dynamically moves according to the measurement result obtained by the measuring device 150. However, as shown in FIG. 10, the bonded substrate stack 50 (the substrate holding portions 105 and 106) can be moved in the vertical direction according to the measurement result obtained by the measuring device 150, so that the position of the nozzle 120 remains fixed without causing The nozzle 120 moves vertically. In addition, the nozzle 120 and the bonding substrate stack 50 can also dynamically move in the vertical direction in synchronization with the bonding substrate stack 50 according to the measurement result obtained by the measuring device 150.

On the other hand, the fluid ejected from the nozzle 120 can always be injected into the concave portion (especially the bonding interface) of the bonding substrate stack 50. This result is achieved by changing the position of the nozzle 120 according to the measurement result obtained by the measuring device 150 The elevation angle of the adjustment mechanism 140 and the elevation angle and position of the nozzle 120 synchronized with the rotation of the bonded substrate stack 50 are adjusted.

FIG. 11 is a graph showing an example of the position crystal 140, which includes a mechanism for adjusting the elevation angle and position of the nozzle 120. The position adjustment mechanism 140 in FIG. 11 includes a first adjustment mechanism 141 and a second adjustment mechanism 142. The first adjustment mechanism is used to adjust the vertical position (position in the plane direction) of the nozzle and the second adjustment mechanism is Used to adjust the elevation angle of the nozzle 120.

The position and axial position of the surrounding part of the bonded substrate stack 50 can be measured in the plane direction, and the nozzle 120 can also be synchronized with the rotation of the bonded substrate stack 50 according to the measurement result and be moved in the plane direction of the bonded substrate stack 50 drive. This is particularly effective when the elevation angle and position of the nozzle 120 change synchronously with the rotation of the bonded substrate stack 50, and when the separation is performed while maintaining a predetermined distance between the nozzle 120 and the bonded substrate stack 50.

The separation of the bonded substrate stack 50 can be performed simultaneously with the measurement of the position of the surrounding portion of the bonded substrate stack 50. In this case, the controller will drive the position adjustment mechanism 140 according to the measurement signals successively provided by the measurement device 150. At this time, if one of the measurement points (rotation angle) of the bonded substrate stack 50 to be measured by the measuring device 150 and the fluid ejection position (rotation angle) almost coincide with each other, then the nozzle (and/or the bonded substrate stack) The drive can be generated according to any dynamic deformation of the bonded substrate stack 50 caused by fluid injection. After any distortion is measured at the part where the fluid is to be injected, the position of the crystal pattern or nozzle will be controlled based on the measured distortion, and the fluid will be injected into this part. Such processing will be repeated one after another.

In the separation apparatus 100 shown in FIG. 2, the bonded substrate stack 50 is held horizontally. However, it is also possible to hold the bonded substrate stack 50 vertically. When the bonding substrate is held horizontally, the bonding substrate stack 50 can be easily transported to other equipment.

Hereinafter, a separation method using the separation device 100 will be explained.

First, the cylinder 110 is activated to move the lower substrate holding portion 106 downward, and the bonded substrate stack 50 is transported to a predetermined position between the pair of substrate holding portions 105 and 106 by a transport robot. The cylinder 110 is activated to move the lower substrate holding portion 106 upward and cause the pair of substrate holding portions 105 and 106 to hold the bonded substrate stack 50. If the pair of substrate holding portions 105 and 106 have a clamping mechanism, the clamping mechanism will be activated to clamp the bonded substrate stack 50. In addition, the cylinder 110 can also be used to apply a certain amount of pressure or tension to the bonded substrate stack 50. It is also possible to hold the bonded substrate stack 50 by applying a pressing force to the bonded substrate stack 50 by the cylinder 110 without clamping the bonded substrate stack 50.

Then, when the bonded substrate stack 50 is rotated by the driving motor 101 under the control of the controller 160, the vertical position of the periphery of the bonded substrate stack 50 is measured by the measuring device 150 (in this embodiment, it is Bond the surrounding portion on the lower surface of the substrate stack 50). This measurement result can be recorded by the controller 160 as the vertical position of the periphery of the bonded substrate stack 50 as a function of the rotation angle of the bonded substrate stack 50. FIGS. 5 and 6 show how to measure the position of the surrounding part of the bonded substrate stack 50 by the measuring device 150.

The motor 101 is driven to rotate the bonding substrate stack 50, and the fluid is ejected from the nozzle 120 under the control of the controller 160. At this time, the controller 160 drives the position adjustment mechanism 140 in synchronization with the rotation of the bonding substrate stack 50 according to the measurement result, so that the fluid sprayed from the nozzle 120 is always injected into the recess of the bonding substrate stack 50. Figures 7 and 8 show a state in which the bonded substrate stack 50 is split.

The bonded substrate stack 50 is separated into two substrates after several rotations.

After the bonded substrate stack 50 has been split, the cylinder 110 is activated to move the lower substrate holding portion 106 downward, and the robot is transported to receive two separated substrates from the substrate holding portions 105 and 106, respectively.

FIG. 9 is an enlarged view of the nozzle 120 and the bonding substrate stack 50. As shown in FIG. 9, the bonded substrate stack 50 or the plate to be separated preferably has a v-shaped recess in its cross section. The formation of this recess in the bonded substrate stack 50 or the plate allows the fluid ejected from the nozzle 120 to be effectively injected into the porous layer 12, and thus can lead to smooth separation at the porous layer 12. As described above, when a first substrate and a second substrate are used to form the bonding substrate stack, the recess 51 is always formed, and each of the first and second substrates has an oblique circular cross-sectional shape. Location.

Preferably, each of the first and second substrates 10 and 20 constituting the bonded substrate stack 50 has a thickness of 100 to 2000 μm, and generally 700 μm. When the first and second substrates have a thickness of 700 μm, the width G of the recess 51 is approximately 700 μm. It is preferable that the diameter D of the fluid ejected from the nozzle 120 is about 50 to 1000 µm and generally 100 µm. At this time, the diameter of the fluid is preferably 1/20 to 1/2 of the width G of the recess 51.

It should be noted that in the present invention, water or liquid of etchant, gas such as air, nitrogen or argon, and a fluid mixture of liquid and gas can be used as the fluid.

The step of controlling at least one of the bonding member and the fluid ejection portion according to the amount of twisting around the member so that the fluid can be injected into the concave portion does not necessarily need to be performed until the bonding member has been completely separated. Instead, this control must be performed only when the bonding member is rotated by 90°, 180°, or 360° in a circle, and then the bonding member can be separated to fix the bonding member and the ejection part in place.

[Examples of semiconductors]

Hereinafter, a semiconductor device and a method of manufacturing the device will be described with reference to FIGS. 12A to 12D, wherein the semiconductor device is manufactured using the semiconductor substrate produced by the above-mentioned substrate manufacturing method.

12A to 12D are cross-sectional views showing a method of manufacturing a semiconductor device using a semiconductor substrate, wherein the semiconductor substrate is manufactured using the substrate manufacturing method of the preferred embodiment of the present invention.

First, an SOI substrate is manufactured using the above-mentioned substrate manufacturing method, with a semiconductor layer as the non-porous layer 13 and an insulating layer as the non-porous layer 14 thereon. The active region 13 of a transistor to be formed and an element isolation region 54 are formed by the following method, which is a method of patterning a non-porous semiconductor layer (SOI layer) into an island shape on the buried insulating layer 14 or The oxidation method called LOCOS (Figure 12A).

Next, a gate insulating film 56 is formed on the surface of the SOI layer (FIG. 12A). The material of the gate insulating film 56 can be silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, tantalum oxide, hafnium oxide, titanium oxide, scandium oxide, yttrium oxide, dimmer oxide, lanthanum oxide, zirconium oxide, and gas mixtures thereof. . The gate oxide film 56 can be formed by oxidizing the surface of the SOI layer or depositing a suitable substance on the surface of the SOI layer by CVD or PVD.

A gate electrode 55 is formed on the gate insulating film 56. The electrode 55 may be made of polysilicon compound doped with p-type or n-type impurities. Such impurity metals include tungsten, molybdenum, titanium, tantalum, aluminum, or copper. Metals or alloys containing at least one of them, or metal silicides such as molybdenum silicide, tungsten silicide, and cobalt silicide, or metal nitrides such as titanium nitride, tungsten nitride, and tantalum nitride. The gate insulating film 56 can be formed by stacking multiple layers formed of different materials. The gate electrode 55 can be formed by the following method, the so-called Salicide (self _- alignsilicide (self-aligned silicide) method, or etched gate processing method, or other methods. Through the above-mentioned processing, the structure shown in FIG. 12A can be obtained.

Secondly, n-type impurities such as phosphorus, antimony, and antimony or p-type impurities such as boron are doped into the active region 13, thereby forming a highly doped source and drain region 58 (FIG. 12B). Impurities can also be doped by ion implantation and annealing.

An insulating film is formed so as to cover the gate electrode 55 and then it is etched back, thereby forming a side wall 59 on the side surface of the gate electrode 55.

The active region 13 is again doped with impurities having the same conductivity as described above, thereby forming a highly doped source and drain region 57. Through the above processing, the structure shown in FIG. 12B can be obtained.

A metal silicide layer 60 is formed on the upper surface of the gate electrode 55 and the upper surface of the source and drain regions 57. The material of the metal silicide layer 60 can be nickel silicide, titanium silicide, cobalt silicide, molybdenum silicide, and tungsten silicide. Such a silicide can be formed in the following manner. A metal is deposited on the upper surface of the gate electrode 55 and the upper surface of the source and drain regions 57, annealing is performed to make the metal react with the underlying silicon, and an etchant is used to remove The unreacted part of this metal. The surface of the silicide layer can also be nitrided if necessary. Through the above processing, the structure shown in FIG. 12C can be obtained.

An insulating film 61 is formed on the upper surface of the gate electrode and the upper surface of the source and drain regions that have become silicide. As the material of the insulating film 61, silicon oxide containing phosphorous electrodes and/or boron can be used.

A contact hole is formed in the insulating film 61 by CMP. When using KrF excimer laser, ArF excimer laser, F ₂ When performing photolithography with excimer lasers, electron beams, or X-rays, rectangular contact holes with sides less than 0.25 μm or circular contact holes with a diameter less than 0.25 μm can be formed.

Second, the contact holes are filled with conductors. In order to fill the contact holes with conductors, a refractory metal film or its nitride as a barrier metal 62 is formed on the inner surface of each contact hole, and then, for example, tungsten alloy, aluminum, aluminum alloy, copper or copper alloy, etc. The conductor 63 will be deposited on it by CVD, PVD or electroplating. The conductor can be deposited higher than the upper surface of the insulating film 61 and removed by etching or CMP. On the other hand, before the contact holes are filled with conductors, the surface of the silicide layer in the source and drain regions can be hydrogenated, and this surface will be exposed at the bottom of each contact hole. Through the above processing, a FET transistor can be formed on the SOI layer, and a semiconductor device having the structure of FIG. 12D can be obtained.

When the thickness and impurity concentration of the active layer (SOI layer) 13 have been defined so that a depletion layer generated by applying a voltage to the gate electrode reaches the upper surface of the buried insulating layer 14, the formed transistor will become a Fully depleted transistor. When the thickness and impurity concentration of the active layer (SOI layer) 13 have been defined, so that the depletion layer does not reach the upper surface of the buried insulating layer 14, the formed transistor will become a part of the depletion type transistor.

According to the present invention, it is possible to always inject fluid into an appropriate position when separating plates such as bonded substrate stacks. In this way, the reproducibility and output when separating the plates can be improved.

Although the present invention has been described above, it should be understood that many modifications and changes will still occur without departing from the spirit and scope of the present invention.