Substrate processing apparatus and method for holding a substrate

Abstract

To provide a technology that can appropriately correct distortion at an outer periphery of a substrate.SOLUTION: A substrate processing device includes a holding portion that attracts and holds a substrate by a suction surface. The suction surface includes an outer suction portion that suctions an outer periphery of the substrate, and an inner suction portion that suctions a part of the substrate inside the outer periphery. The holding portion includes a deforming portion that deforms the outer suction portion relative to the inner suction portion.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present disclosure relates to a substrate processing apparatus and a method for holding a substrate.

Background Art

[0002] Patent Document 1 discloses a substrate processing apparatus (bonding apparatus) including an upper chuck that sucks an upper substrate from above and a lower chuck that sucks a lower substrate from below, and bonding two substrates facing each other. In bonding the substrates, the substrate processing apparatus pushes down the center of the substrate on the upper chuck to contact the center of the substrate on the lower chuck, and bonds the centers of the two substrates by intermolecular force, and expands this bonding region from the center to the outer edge.

[0003] In this type of substrate processing apparatus, when there is a relative difference in elongation and contraction on the bonding surfaces of the two substrates during bonding, the reference points of the upper substrate and the lower substrate are displaced. In particular, at the outer peripheral portion of the substrate, the displacement of the reference point tends to be large.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides a technique capable of appropriately correcting the distortion of the outer peripheral portion of a substrate.

Means for Solving the Problems

[0006] According to one aspect of the present disclosure, a substrate processing apparatus is provided, comprising a holding portion that adsorbs and holds a substrate by an adsorption surface, wherein the adsorption surface includes an outer adsorption portion that adsorbs the outer periphery of the substrate and an inner adsorption portion that adsorbs the portion of the substrate inside the outer periphery, and the holding portion has a deformation portion that deforms the outer adsorption portion relative to the inner adsorption portion. [Effects of the Invention]

[0007] According to one embodiment, distortion of the outer periphery of the substrate can be appropriately corrected. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view showing the joining device. [Figure 2] Figure 1 is a side view of the joining device. [Figure 3] This is a side view showing an example of the first and second substrates. [Figure 4] This is a flowchart showing the joining method. [Figure 5] This is a plan view showing an example of a joint module according to the first embodiment. [Figure 6] Figure 5 is a side view of the joint module. [Figure 7] This is a cross-sectional view showing an example of an upper zipper and a lower zipper. [Figure 8] Figure 4 is a flowchart detailing step S109. [Figure 9] Figure 9(A) is a side view showing an example of the operation in step S112 of Figure 8. Figure 9(B) is a side view showing the operation following Figure 9(A). Figure 9(C) is a side view showing the operation following Figure 9(B). [Figure 10] Figure 10(A) is a cross-sectional view showing an example of the operation in step S113 of Figure 8. Figure 10(B) is a cross-sectional view showing an example of the operation in step S114 of Figure 8. Figure 10(C) is a cross-sectional view showing the operation following Figure 10(B). [Figure 11] This is a cross-sectional view showing a configuration for deforming the outer suction portion of the lower chuck according to the first embodiment. [Figure 12] Figure 12(A) is a plan view of the lower chuck. Figure 12(B) is a plan view showing the position of the suction surface when the outer suction part of the lower chuck is expanded. [Figure 13] This is a cross-sectional perspective view showing a magnified view of the deformed portion of the lower chuck. [Figure 14] Figure 14(A) is a cross-sectional view showing a configuration in which the outer suction portion is bulging. Figure 14(B) is a cross-sectional view showing a configuration in which the outer suction portion is contracted. Figure 14(C) is a cross-sectional view showing a configuration in which the outer edge of the substrate is positioned outside the midpoint of the width direction of the outer suction portion. [Figure 15] This is a flowchart showing the method for holding the circuit board. [Figure 16] This is a plan view of the lower chuck in a modified example. [Figure 17] This is a cross-sectional view showing a configuration for deforming the outer suction portion of the lower chuck according to the second embodiment. [Figure 18] This is a perspective view showing the outer suction section of the lower chuck, which is divided into multiple sections. [Figure 19] Figure 19(A) is a cross-sectional view showing another first configuration example of the deformable part. Figure 19(B) is a cross-sectional view showing another second configuration example of the deformable part. Figure 19(C) is a cross-sectional view showing another third configuration example of the deformable part. Figure 19(D) is a cross-sectional view showing another fourth configuration example of the deformable part. [Modes for carrying out the invention]

[0009] The embodiments for implementing this disclosure will be described below with reference to the drawings. In each drawing, the same components are denoted by the same reference numeral, and redundant explanations may be omitted. In the following description, the X-axis, Y-axis, and Z-axis directions are perpendicular to each other, the X-axis and Y-axis directions are horizontal, and the Z-axis direction is vertical.

[0010] As a substrate processing apparatus of the present disclosure, the bonding apparatus 1 shown in FIGS. 1 and 2 will be typically described. The bonding apparatus 1 bonds the first substrate W1 and the second substrate W2 to produce a bonded substrate T. At least one of the first substrate W1 and the second substrate W2 is a substrate on which a plurality of electronic circuits are formed on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. One of the first substrate W1 and the second substrate W2 may be a bare wafer on which no electronic circuit is formed. The compound semiconductor wafer is not particularly limited, but is, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer.

[0011] The first substrate W1 and the second substrate W2 are formed as disks having substantially the same shape (same diameter). As shown in FIG. 3, the bonding apparatus 1 arranges the second substrate W2 on the negative Z-axis side (vertically downward side) of the first substrate W1 to bond the first substrate W1 and the second substrate W2. Therefore, hereinafter, the first substrate W1 may be referred to as the "upper wafer W1", the second substrate W2 may be referred to as the "lower wafer W2", and the bonded substrate T may be referred to as the "bonded wafer T". Further, hereinafter, among the plate surfaces of the upper wafer W1, the plate surface on the side bonded to the lower wafer W2 is referred to as the "bonding surface W1j", and the plate surface on the opposite side to the bonding surface W1j is referred to as the "non-bonding surface W1n". Also, among the plate surfaces of the lower wafer W2, the plate surface on the side bonded to the upper wafer W1 is referred to as the "bonding surface W2j", and the plate surface on the opposite side to the bonding surface W2j is referred to as the "non-bonding surface W2n".

[0012] As shown in FIG. 1, the bonding apparatus 1 includes a loading / unloading station 2 and a processing station 3 in this order in the positive X-axis direction. The loading / unloading station 2 and the processing station 3 are integrally connected.

[0013] The loading / unloading station 2 comprises a mounting table 10 and a transport area 20. The mounting table 10 has a plurality of mounting plates 11. Cassettes CS1, CS2, and CS3, each containing multiple substrates (for example, 25) in a horizontal position, are mounted on each mounting plate 11. Cassette CS1 is a cassette for containing the upper wafer W1, cassette CS2 is a cassette for containing the lower wafer W2, and cassette CS3 is a cassette for containing the bonded wafer T. In cassettes CS1 and CS2, the upper wafer W1 and the lower wafer W2 are contained aligned with their bonding surfaces W1j and W2j facing upwards, respectively.

[0014] The transport area 20 is located adjacent to the positive X-axis side of the mounting table 10 and includes a transport path 21 extending in the Y-axis direction and a transport device 22 that is movable along this transport path 21. The transport device 22 is movable in the X-axis direction and can rotate around the Z-axis, and transports the upper wafer W1, lower wafer W2, and bonded wafer T between the cassettes CS1 to CS3 placed on the mounting table 10 and the third processing block PB3 of the processing station 3, which will be described later.

[0015] The processing station 3 comprises, for example, three processing blocks PB1, PB2, and PB3. The first processing block PB1 is located on the rear side of the processing station 3 (the positive Y-axis side in Figure 1). The second processing block PB2 is located on the front side of the processing station 3 (the negative Y-axis side in Figure 1). The third processing block PB3 is located on the loading / unloading station 2 side of the processing station 3 (the negative X-axis side in Figure 1).

[0016] Furthermore, the processing station 3 includes a transport area 60 containing a transport device 61, located in the region enclosed by the first processing block PB1 to the third processing block PB3. For example, the transport device 61 has a transport arm that is movable vertically, horizontally, and around the vertical axis. The transport device 61 moves within the transport area 60 and transports the upper wafer W1, lower wafer W2, and bonded wafer T to the devices in the first processing block PB1, second processing block PB2, and third processing block PB3 adjacent to the transport area 60.

[0017] The first processing block PB1 includes, for example, a surface modification device 33 and a surface hydrophilization device 34. The surface modification device 33 modifies the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2. The surface hydrophilization device 34 hydrophilizes the modified bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2.

[0018] For example, the surface modification apparatus 33 breaks the SiO2 bonds at the bonding surfaces W1j and W2j, forming unbonded Si bonds and enabling subsequent hydrophilization. In the surface modification apparatus 33, for example, under a reduced pressure atmosphere, oxygen gas, which is the processing gas, is excited and plasma-generated, and then ionized. The oxygen ions are then irradiated onto the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2, thereby plasma-treated and modified the bonding surfaces W1j and W2j. The processing gas is not limited to oxygen gas; nitrogen gas or the like may also be used.

[0019] The surface hydrophilization device 34 hydrophilizes the bonding surface W1j of the upper wafer W1 and W2j of the lower wafer W2 using a hydrophilization treatment liquid such as pure water. The surface hydrophilization device 34 also has the role of cleaning the bonding surfaces W1j and W2j. In the surface hydrophilization device 34, for example, the upper wafer W1 or lower wafer W2 held in a spin chuck is rotated while pure water is supplied onto the upper wafer W1 or lower wafer W2. As a result, the pure water diffuses over the bonding surfaces W1j and W2j, OH groups attach to the unbonded Si, and the bonding surfaces W1j and W2j are hydrophilized.

[0020] As shown in Figure 2, the second processing block PB2 includes, for example, a bonding module 41, a first temperature control device 42, and a second temperature control device 43. The bonding module 41 bonds a hydrophilized upper wafer W1 and a lower wafer W2 to produce a bonded wafer T. The first temperature control device 42 adjusts the temperature distribution of the upper wafer W1 before producing the bonded wafer T. The second temperature control device 43 adjusts the temperature distribution of the lower wafer W2 before producing the bonded wafer T. In this embodiment, the first temperature control device 42 and the second temperature control device 43 are provided separately from the bonding module 41, but they may also be provided as part of the bonding module 41.

[0021] The third processing block PB3 includes, for example, a first position adjustment device 51, a second position adjustment device 52, and transition devices 53 and 54 in order from top to bottom. Note that the placement of each device in the third processing block PB3 is not limited to the placement shown in Figure 2. The first position adjustment device 51 adjusts the horizontal orientation of the upper wafer W1 and also inverts the upper wafer W1 so that the bonding surface W1j of the upper wafer W1 faces downward. The second position adjustment device 52 adjusts the horizontal orientation of the lower wafer W2. The transition device 53 temporarily places the upper wafer W1 on it. The transition device 54 temporarily places the lower wafer W2 or the bonded wafer T on it.

[0022] Returning to Figure 1, the bonding apparatus 1 includes a control device (control unit) 90 that controls each component. The control device 90 is a control computer having one or more processors 91, memory 92, input / output interfaces (not shown), and electronic circuits. The one or more processors 91 are a combination of one or more of the following: a CPU, ASIC, FPGA, a circuit consisting of multiple discrete semiconductors, etc., and execute programs stored in the memory 92. The memory 92 includes non-volatile memory and volatile memory and forms the storage unit of the control device 90.

[0023] Next, the joining method of this embodiment will be described with reference to Figure 4. Steps S101 to S109 shown in Figure 4 are carried out under the control of the control device 90.

[0024] In the joining method, an operator or a transport robot (not shown) places a cassette CS1 containing multiple upper wafers W1, a cassette CS2 containing multiple lower wafers W2, and an empty cassette CS3 on the loading platform 10 of the loading / unloading station 2.

[0025] The bonding apparatus 1 uses the transport device 22 to remove the upper wafer W1 from the cassette CS1 and transports it to the transition device 53 of the third processing block PB3 of the processing station 3. Subsequently, the bonding apparatus 1 uses the transport device 61 to remove the upper wafer W1 from the transition device 53 and transports it to the surface modification device 33 of the first processing block PB1.

[0026] Next, the bonding apparatus 1 modifies the bonding surface W1j of the upper wafer W1 using the surface modification apparatus 33 (step S101). The surface modification apparatus 33 modifies the bonding surface W1j with the bonding surface W1j facing upwards. After that, the transport apparatus 61 removes the upper wafer W1 from the surface modification apparatus 33 and transports it to the surface hydrophilization apparatus 34.

[0027] Then, the bonding apparatus 1 uses the surface hydrophilization apparatus 34 to hydrophilize the bonding surface W1j of the upper wafer W1 (step S102). The surface hydrophilization apparatus 34 hydrophilizes the bonding surface W1j with the bonding surface W1j facing upwards. After that, the transport apparatus 61 removes the upper wafer W1 from the surface hydrophilization apparatus 34 and transports it to the first position adjustment apparatus 51 of the third processing block PB3.

[0028] The bonding apparatus 1 adjusts the horizontal orientation of the upper wafer W1 using the first position adjustment device 51 and also inverts the upper wafer W1 vertically (step S103). As a result, the notch of the upper wafer W1 is oriented in a predetermined direction and the bonding surface W1j of the upper wafer W1 is oriented downwards. Subsequently, the transport device 61 removes the upper wafer W1 from the first position adjustment device 51 and transports it to the first temperature control device 42 of the second processing block PB2.

[0029] The bonding apparatus 1 adjusts the temperature of the upper wafer W1 using the first temperature control device 42 (step S104). The temperature control of the upper wafer W1 is performed with the bonding surface W1j of the upper wafer W1 facing downwards. Subsequently, the transport device 61 removes the upper wafer W1 from the first temperature control device 42 and transports it to the bonding module 41.

[0030] The bonding apparatus 1 performs the above-mentioned processing on the upper wafer W1 in parallel with the processing on the lower wafer W2. First, the bonding apparatus 1 uses the transport device 22 to remove the lower wafer W2 from the cassette CS2 and transports it to the transition device 54 of the third processing block PB3 of the processing station 3. Then, the transport device 61 removes the lower wafer W2 from the transition device 54 and transports it to the surface modification device 33 of the first processing block PB1.

[0031] The bonding apparatus 1 modifies the bonding surface W2j of the lower wafer W2 using the surface modification apparatus 33 (step S105). The surface modification apparatus 33 modifies the bonding surface W2j with the bonding surface W2j facing upwards. After that, the transport apparatus 61 removes the lower wafer W2 from the surface modification apparatus 33 and transports it to the surface hydrophilization apparatus 34.

[0032] The bonding apparatus 1 uses the surface hydrophilization apparatus 34 to hydrophilize the bonding surface W2j of the lower wafer W2 (step S106). The surface hydrophilization apparatus 34 hydrophilizes the bonding surface W2j with the bonding surface W2j facing upwards. After that, the transport apparatus 61 removes the lower wafer W2 from the surface hydrophilization apparatus 34 and transports it to the second position adjustment apparatus 52 of the third processing block PB3.

[0033] The bonding apparatus 1 adjusts the horizontal orientation of the lower wafer W2 using the second position adjustment device 52 (step S107). This ensures that the notch of the lower wafer W2 is oriented in a predetermined direction. Subsequently, the transport device 61 removes the lower wafer W2 from the second position adjustment device 52 and transports it to the second temperature control device 43 of the second processing block PB2.

[0034] The bonding apparatus 1 adjusts the temperature of the lower wafer W2 using the second temperature control device 43 (step S108). The temperature control of the lower wafer W2 is performed with the bonding surface W2j of the lower wafer W2 facing upwards. After that, the transport device 61 removes the lower wafer W2 from the second temperature control device 43 and transports it to the bonding module 41.

[0035] Then, the bonding apparatus 1 bonds the upper wafer W1 and the lower wafer W2 in the bonding module 41 to produce a bonded wafer T (step S109). After the bonded wafer T is produced, the transport apparatus 61 removes the bonded wafer T from the bonding module 41 and transports it to the transition apparatus 54 of the third processing block PB3.

[0036] Finally, the bonding apparatus 1 uses the transport device 22 to remove the bonded wafer T from the transition apparatus 54 and transport it to the cassette CS3 on the mounting table 10. This completes the series of processes.

[0037] [First Embodiment] Next, an example of a bonding module 41 according to the first embodiment will be described with reference to Figures 5 to 7. As shown in Figure 5, the bonding module 41 has a processing container 210 that can be sealed inside. An input / output port 211 is formed on the side of the processing container 210 on the transport area 60 side, and an opening / closing shutter 212 is provided at the input / output port 211. The upper wafer W1, the lower wafer W2, and the bonding wafer T are input and output through the input / output port 211.

[0038] As shown in Figure 6, an upper chuck 230 and a lower chuck 231 are provided inside the processing container 210. The upper chuck 230 holds the upper wafer W1 from above with its bonding surface W1j facing downwards. The lower chuck 231 is located below the upper chuck 230 and holds the lower wafer W2 from below with its bonding surface W2j facing upwards.

[0039] The upper chuck 230 is supported by a support member 280 provided on the ceiling surface of the processing container 210. On the other hand, the lower chuck 231 is supported by a first lower chuck moving part 291 provided below the lower chuck 231.

[0040] The first lower chuck moving part 291 moves the lower chuck 231 horizontally (in the Y-axis direction), as will be described later. The first lower chuck moving part 291 is also configured to allow the lower chuck 231 to move vertically and rotate around a vertical axis.

[0041] The first lower chuck moving part 291 is provided on the lower side of the first lower chuck moving part 291 and is attached to a pair of rails 295 that extend horizontally (in the Y-axis direction). The first lower chuck moving part 291 is configured to be movable along the rails 295. The rails 295 are provided on the second lower chuck moving part 296.

[0042] The second lower chuck moving part 296 is provided on the lower side of the second lower chuck moving part 296 and is attached to a pair of rails 297 that extend horizontally (in the X-axis direction). The second lower chuck moving part 296 is configured to move freely along the rails 297. The pair of rails 297 are provided on a mounting part 298 provided on the bottom surface of the processing container 210.

[0043] The moving mechanism 290 is composed of a first lower chuck moving part 291 and a second lower chuck moving part 296. The moving mechanism 290 moves the lower chuck 231 relative to the upper chuck 230. The moving mechanism 290 also moves the lower chuck 231 between the substrate transfer position and the bonding position.

[0044] The substrate transfer position is the position where the upper chuck 230 receives the upper wafer W1 from the transport device 61, the lower chuck 231 receives the lower wafer W2 from the transport device 61, and the lower chuck 231 transfers the bonded wafer T to the transport device 61. The substrate transfer position is the position where the transfer of the bonded wafer T produced in the nth (n is a natural number greater than or equal to 1)th bonding is carried out, and the transfer of the upper wafer W1 and lower wafer W2 to be bonded in the (n+1)th bonding is carried out in succession. The substrate transfer position is, for example, the position shown in Figures 5 and 6.

[0045] When the transfer device 61 transfers the upper wafer W1 to the upper chuck 230, it moves directly below the upper chuck 230. Also, when the transfer device 61 receives the bonded wafer T from the lower chuck 231 and transfers the lower wafer W2 to the lower chuck 231, it moves directly above the lower chuck 231. To facilitate the transfer device 61's movement, the upper chuck 230 and the lower chuck 231 are offset laterally, and the vertical distance between the upper chuck 230 and the lower chuck 231 is also large.

[0046] On the other hand, the bonding position is a position where the upper wafer W1 and the lower wafer W2 are facing each other with a predetermined distance between them (opposing position). The bonding position is, for example, the position shown in Figure 7. At the bonding position, the distance between the upper wafer W1 and the lower wafer W2 in the vertical direction is narrower compared to the substrate transfer position. Also, at the bonding position, unlike the substrate transfer position, the upper wafer W1 and the lower wafer W2 overlap when viewed in the vertical direction.

[0047] The moving mechanism 290 moves the relative positions of the upper chuck 230 and the lower chuck 231 in the horizontal direction (both in the X-axis and Y-axis directions) and in the vertical direction. In this embodiment, the moving mechanism 290 moves the lower chuck 231, but it may move either the lower chuck 231 or the upper chuck 230, or both. The moving mechanism 290 may also rotate the upper chuck 230 or the lower chuck 231 around the vertical axis.

[0048] As shown in Figure 7, the upper chuck 230 is divided into multiple (e.g., three) regions 230a, 230b, and 230c along its radial direction. These regions 230a, 230b, and 230c are arranged in this order from the center of the upper chuck 230 toward the outer edge. Region 230a is formed in a circular shape in plan view, while regions 230b and 230c are formed in annular shapes in plan view.

[0049] Each of the regions 230a, 230b, and 230c is independently provided with suction tubes 240a, 240b, and 240c. Each of the suction tubes 240a, 240b, and 240c is connected to a different vacuum pump 241a, 241b, and 241c, respectively. The upper chuck 230 is capable of vacuum-suctioning the upper wafer W1 in each of the regions 230a, 230b, and 230c.

[0050] The upper chuck 230 is provided with a plurality of retaining pins 245 that can move up and down vertically. The plurality of retaining pins 245 are connected to a vacuum pump 246, and the upper wafer W1 is vacuum-adsorbed by the operation of the vacuum pump 246. The upper wafer W1 is vacuum-adsorbed to the lower ends of the plurality of retaining pins 245. A ring-shaped suction pad may be used instead of the plurality of retaining pins 245.

[0051] Multiple retaining pins 245 are lowered by a drive unit (not shown) and protrude from the suction surface of the upper chuck 230. In this state, the multiple retaining pins 245 vacuum-suction the upper wafer W1 and receive it from the transport device 61. Subsequently, the multiple retaining pins 245 rise, and the upper wafer W1 comes into contact with the suction surface of the upper chuck 230. Then, the upper chuck 230 horizontally vacuum-suctions the upper wafer W1 in each region 230a, 230b, and 230c by the operation of vacuum pumps 241a, 241b, and 241c.

[0052] Furthermore, the upper chuck 230 is equipped with a through hole 243 that penetrates vertically through the upper chuck 230. A pushing part 250 is inserted through the through hole 243. The pushing part 250 presses down on the center of the upper wafer W1, which is positioned at a distance from the lower wafer W2, thereby bringing the upper wafer W1 into contact with the lower wafer W2.

[0053] The pushing section 250 includes a pushing pin 251 and an outer cylinder 252 which is a lifting guide for the pushing pin 251. The pushing pin 251 is inserted through a through hole 243 by, for example, a drive unit (not shown) with a built-in motor, protrudes from the suction surface of the upper chuck 230, and pushes down the center of the upper wafer W1.

[0054] Furthermore, the lower chuck 231 is also divided into multiple (for example, two) regions 231a and 231b along its radial direction. These regions 231a and 231b are provided in this order from the center of the lower chuck 231 toward the outer edge. Region 231a is formed in a circular shape in plan view, and region 231b is formed in an annular shape in plan view. Region 231b may have multiple arc-shaped zones (small regions) along its circumferential direction.

[0055] Each region 231a and 231b is independently provided with suction tubes 260a and 260b. Each suction tube 260a and 260b is connected to a different vacuum pump 261a and 261b, respectively. This allows the lower chuck 231 to vacuum-suction the lower wafer W2 for each region 231a and 231b.

[0056] The lower chuck 231 is provided with a plurality (for example, three) of retaining pins 265 that can move up and down vertically. The lower wafer W2 is placed on the upper ends of the plurality of retaining pins 265. Alternatively, the lower wafer W2 may be vacuum-suctioned to the upper ends of the plurality of retaining pins 265.

[0057] As the multiple retaining pins 265 rise, they protrude from the suction surface of the lower chuck 231. In this state, the multiple retaining pins 265 receive the lower wafer W2 from the transport device 61. Subsequently, as the multiple retaining pins 265 descend, the lower wafer W2 comes into contact with the suction surface 300 of the lower chuck 231. Then, the lower chuck 231 horizontally vacuum-adsorbs the lower wafer W2 over multiple regions of the suction surface 300.

[0058] Next, with reference to Figures 8 to 10, the process of manufacturing the bonded wafer T in step S109 of Figure 4 will be described in detail. As shown in Figure 8, the control device 90 loads the upper wafer W1 and the lower wafer W2 into the bonding module 41 using the transport device 61 (step S111). The relative positions of the upper chuck 230 and the lower chuck 231 after loading are the substrate transfer positions shown in Figures 6 and 7.

[0059] Next, the control device 90 uses the moving mechanism 290 to move the relative positions of the upper chuck 230 and the lower chuck 231 from the substrate transfer position to the bonding position shown in Figure 7 (step S112). In step S112, the control device 90 uses the first camera S1 and the second camera S2, as shown in Figure 9, to align the upper wafer W1 and the lower wafer W2.

[0060] The first camera S1 is fixed to the upper chuck 230 and images the lower wafer W2 held by the lower chuck 231. Multiple reference points P21 to P23 are formed in advance on the bonding surface W2j of the lower wafer W2. Patterns such as electronic circuits are used as reference points P21 to P23. The number of reference points can be set arbitrarily.

[0061] Meanwhile, the second camera S2 is fixed to the lower chuck 231 and images the upper wafer W1 held by the upper chuck 230. Multiple reference points P11 to P13 are pre-formed on the bonding surface W1j of the upper wafer W1. Patterns such as electronic circuits are used as reference points P11 to P13. The number of reference points can be set arbitrarily.

[0062] As shown in Figure 9(A), the joining module 41 adjusts the relative horizontal positions of the first camera S1 and the second camera S2 using the moving mechanism 290. Specifically, the moving mechanism 290 moves the lower chuck 231 horizontally so that the second camera S2 is positioned approximately directly below the first camera S1. Then, the moving mechanism 290 fine-tunes the horizontal position of the second camera S2 so that the first camera S1 and the second camera S2 image a common target X and their horizontal positions coincide.

[0063] Next, as shown in Figure 9(B), the moving mechanism 290 moves the lower chuck 231 vertically upward to adjust the horizontal position of the upper chuck 230 and the lower chuck 231. Specifically, while the moving mechanism 290 moves the lower chuck 231 horizontally, the first camera S1 sequentially images the reference points P21 to P23 of the lower wafer W2, and the second camera S2 sequentially images the reference points P11 to P13 of the upper wafer W1. Figure 9(B) shows the first camera S1 imaging the reference point P21 of the lower wafer W2 and the second camera S2 imaging the reference point P11 of the upper wafer W1.

[0064] The first camera S1 and the second camera S2 transmit the captured image data to the control device 90. The control device 90 controls the movement mechanism 290 based on the image data captured by the first camera S1 and the image data captured by the second camera S2, and adjusts the horizontal position of the lower chuck 231 so that the reference points P11 to P13 of the upper wafer W1 and the reference points P21 to P23 of the lower wafer W2 coincide in a vertical view.

[0065] Next, as shown in Figure 9(C), the moving mechanism 290 moves the lower chuck 231 vertically upward. As a result, the distance G (see Figure 7) between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 becomes a predetermined distance, for example, 80 μm to 200 μm. The distance G is adjusted using the first displacement meter S3 and the second displacement meter S4.

[0066] The first displacement meter S3, like the first camera S1, is fixed to the upper chuck 230 and measures the thickness of the lower wafer W2 held by the lower chuck 231. The first displacement meter S3 measures the thickness of the lower wafer W2 by, for example, irradiating light onto the lower wafer W2 and receiving the reflected light reflected from both the upper and lower surfaces of the lower wafer W2. This thickness measurement is performed, for example, when the moving mechanism 290 moves the lower chuck 231 in the horizontal direction. The measurement method of the first displacement meter S3 is, for example, a confocal method, a spectral interferometry method, or a triangulation method. The light source of the first displacement meter S3 is an LED or a laser.

[0067] On the other hand, the second displacement sensor S4, like the second camera S2, is fixed to the lower chuck 231 and measures the thickness of the upper wafer W1 held by the upper chuck 230. The second displacement sensor S4 measures the thickness of the upper wafer W1 by, for example, irradiating light onto the upper wafer W1 and receiving the reflected light reflected from both the upper and lower surfaces of the upper wafer W1. This thickness measurement is performed, for example, when the moving mechanism 290 moves the lower chuck 231 in the horizontal direction. The measurement method of the second displacement sensor S4 is, for example, a confocal method, a spectral interferometry method, or a triangulation method. The light source of the second displacement sensor S4 is an LED or a laser.

[0068] The first displacement sensor S3 and the second displacement sensor S4 transmit the measured data to the control device 90. The control device 90 controls the moving mechanism 290 based on the data measured by the first displacement sensor S3 and the data measured by the second displacement sensor S4, and adjusts the vertical position of the lower chuck 231 so that the interval G is set to a set value.

[0069] Next, the operation of the vacuum pump 241a is stopped, and the vacuum suction of the upper wafer W1 in region 230a is released, as shown in Figure 10(A). Then, the push pin 251 of the push unit 250 descends and pushes down the center of the upper wafer W1, bringing the upper wafer W1 into contact with the lower wafer W2 (step S113). As a result, the centers of the upper wafer W1 and the lower wafer W2 are joined together.

[0070] Since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are both modified, van der Waals forces (intermolecular forces) are first generated between the bonding surfaces W1j and W2j, and these bonding surfaces W1j and W2j are joined together. Furthermore, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are both hydrophilized, hydrophilic groups (e.g., OH groups) form hydrogen bonds, and the bonding surfaces W1j and W2j are firmly joined together.

[0071] Next, the control device 90 stops the operation of the vacuum pump 241b and releases the vacuum adsorption of the upper wafer W1 in region 230b, as shown in Figure 11(B). Subsequently, the control device 90 stops the operation of the vacuum pump 241c and releases the vacuum adsorption of the upper wafer W1 in region 230c, as shown in Figure 11(C).

[0072] In this way, the vacuum adsorption of the upper wafer W1 is gradually released from the center toward the periphery, and the upper wafer W1 gradually falls toward the lower wafer W2 and comes into contact with it. The bonding of the upper wafer W1 and the lower wafer W2 then proceeds sequentially from the center toward the periphery (step S114). As a result, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into contact over their entire surfaces, the upper wafer W1 and the lower wafer W2 are bonded together, and a bonded wafer T is obtained. After that, the bonding apparatus 1 raises the push pin 251 back to its original position.

[0073] After the bonding wafer T is formed, the control device 90 uses the moving mechanism 290 to move the relative positions of the upper chuck 230 and the lower chuck 231 from the bonding position shown in Figure 8 to the substrate transfer position shown in Figures 6 and 7 (step S115). For example, the moving mechanism 290 first lowers the lower chuck 231 to increase the vertical distance between the lower chuck 231 and the upper chuck 230. Subsequently, the moving mechanism 290 moves the lower chuck 231 laterally, shifting the lower chuck 231 and the upper chuck 230 laterally.

[0074] Subsequently, the control device 90 uses the transport device 61 to unload the bonded wafer T from the bonded module 41 (step S116). Specifically, first, the lower chuck 231 releases its grip on the bonded wafer T. Then, the multiple holding pins 265 rise, passing the bonded wafer T to the transport device 61. After that, the multiple holding pins 265 descend back to their original positions.

[0075] Next, the configuration of the lower chuck (holding part) 231 according to this embodiment will be described with reference to Figure 11. The lower chuck 231 has the function of deforming the height (shape) of the outer periphery of the suction surface 300 to hold the lower wafer W2 in order to correct the distortion of the outer periphery of the wafer. In Figure 11 and subsequent figures, the suction surface 300 is depicted as flat, but the suction surface 300 may also be configured to have a plurality of ribs extending in the radial direction and a plurality of ribs encircling in the circumferential direction.

[0076] Here, when the bonded wafer T, formed by joining the upper wafer W1 and the lower wafer W2, is measured for the deviation between the reference points P11-P13 of the upper wafer W1 and the reference points P21-P23 of the lower wafer W2 after joining, the deviation of the reference points tends to be larger at the outer periphery of the bonded wafer T. This is because, before joining, the strain of the bonding surfaces W1j and W2j is more apparent at the outer periphery than at the center of the upper wafer W1 and lower wafer W2. Therefore, the lower chuck 231 controls the height of the outer periphery of the suction surface 300, thereby expanding and contracting the bonding surfaces W1j and W2j in accordance with the difference in relative strain at the outer periphery of the upper wafer W1 and the lower wafer W2, and reducing the deviation of the reference points.

[0077] Specifically, the suction surface 300 of the lower chuck 231 has an outer suction portion 301 that suctions the outer periphery of the lower wafer W2, and an inner suction portion 302 that suctions the portion of the lower wafer W2 that is inside the outer periphery. The inner suction portion 302 is formed in a circular shape in plan view, and the outer suction portion 301 is formed in an annular shape at an adjacent position outside the inner suction portion 302.

[0078] The inner adsorption portion 302 has the regions 231a and 231b (see Figure 7) described above. The outer adsorption portion 301 overlaps with a part of region 231b and is configured to apply the adsorption pressure of region 231b to the outer periphery of the lower wafer W2. For example, in the lower chuck 231, the portion forming the outer adsorption portion 301 has a plurality of internal channels 305 extending radially outward from the suction tube 260b (see Figure 7), and adsorption holes 306 that communicate with the adsorption surface 300 (outer adsorption portion 301) from each internal channel 305. As a result, the lower chuck 231 adsorbs the area from the center to the outer periphery of the lower wafer W2 by the inner adsorption portion 302, while adsorbing the outer periphery of the lower wafer W2 by the outer adsorption portion 301.

[0079] Furthermore, the lower chuck 231 is equipped with a function on both its interior and exterior that deforms the outer suction portion 301 relative to the inner suction portion 302. Specifically, the lower chuck 231 has a base member 310 mounted on the moving mechanism 290 and a holding member 320 stacked on the base member 310 to directly hold the lower wafer W2. The lower chuck 231 is equipped with a deformation portion 321 on the outer circumference of the holding member 320 that deforms the outer suction portion 301.

[0080] The base member 310 has a convex shape when viewed in a side cross-sectional view along the vertical direction (see Figure 11), with a base portion 311 fixed to the moving mechanism 290 (the moving stage of the moving mechanism 290), and a projection 312 that protrudes briefly upward in the vertical direction from the central part of the base portion 311. The base member 310 supports the entire holding member 320 in the horizontal direction by fixing the opposite side (back surface) of the inner suction portion 302 of the holding member 320 to the upper end surface of the projection 312.

[0081] Therefore, the lower chuck 231 forms a clearance 313 between the upper surface of the base portion 311 of the base member 310 and the back surface (e.g., the bottom surface) of the outer suction portion 301 of the holding member 320, radially outside the projection 312, creating a gap between the members. Here, the joining module 41 has a mirror 314 set near the lower chuck 231 that reflects light from a displacement meter (not shown) that measures the horizontal position when the moving mechanism 290 moves in three dimensions. The mirror 314 and the base member 310 are positioned apart on the moving stage of the moving mechanism 290. If the base member 310 were to deform in accordance with the deformation of the deformable portion 321 of the lower chuck 231, it could affect the reflection of the adjacent mirror 314.

[0082] Therefore, by not supporting the back surface of the outer suction part 301 with the base member 310, the lower chuck 231 can prevent the deformation of the outer suction part 301 from being transmitted to the base member 310. In other words, even with a structure that deforms the outer suction part 301, the joining device 1 can stabilize the reflection of the mirror 314 and improve the measurement accuracy near the lower chuck 231, making it possible to stably perform positioning of the lower chuck 231, etc.

[0083] Furthermore, the retaining member 320 according to this embodiment has a deformation space 322 that constitutes a deformation portion 321 located below the outer suction portion 301 (inside the outer suction portion 301, overlapping it vertically). The deformation space 322 is a space enclosed by the lower wall 323, upper wall 324, outer peripheral wall 325, and inner peripheral wall 326 of the retaining member 320 in a cross-sectional view along the vertical direction. The deformation space 322 is formed in a rectangular shape with a longer side in the horizontal direction, under the same pressure as the outside pressure of the retaining member 320. The lower wall 323, upper wall 324, outer peripheral wall 325, and inner peripheral wall 326 may be integrally molded members, or some of the walls may be made of different members. For example, the retaining member 320 may have a lower wall 323 made of a material with a high modulus of elasticity (hard), while the upper wall 324, outer peripheral wall 325, and inner peripheral wall 326 may be made of a material with a lower modulus of elasticity (softer) than the lower wall 323.

[0084] The upper wall 324, which constitutes the deformation space 322, is provided with the aforementioned internal flow channels 305 and suction holes 306. The thickness of the upper wall 324 (between the surface (e.g., top surface) of the outer suction portion 301 and the deformation space 322) is thinner than the thickness of the lower wall 323 (between the back surface (e.g., bottom surface) of the outer suction portion 301 and the deformation space 322). Therefore, when the internal pressure in the deformation space 322 fluctuates, the upper wall 324 deforms significantly, while the lower wall 323, outer peripheral wall 325, and inner peripheral wall 326 hardly deform at all. As a result, the lower chuck 231 deforms the upper wall 324 in accordance with the fluctuations in the internal pressure of the deformation space 322, thereby stably and reliably deforming the outer suction portion 301.

[0085] Furthermore, as shown in Figure 12(A), the deformation space 322 is formed in an annular shape that circulates inside the holding member 320 which constitutes the suction surface 300. Therefore, the internal pressure of the deformation space 322 is applied uniformly in the circumferential direction of the holding member 320. Consequently, the lower chuck 231 can deform the outer suction portion 301 integrally and uniformly over the entire circumferential direction in response to fluctuations in the internal pressure of the deformation space 322.

[0086] For example, by increasing the internal pressure of the deformation space 322, the upper wall 324 of the holding member 320 bulges out over the entire circumferential direction, as shown in Figure 12(B). In Figure 12(B), the white color indicates the vertical height (position) of the reference inner suction portion 302 on the suction surface 300, and the blacker the color, the higher the height of the suction surface 300. In this way, the lower chuck 231 can uniformly deform the outer periphery of the lower wafer W2 by deforming the height of the outer suction portion 301 over the entire circumferential direction as the deformation portion 321 deforms.

[0087] Returning to Figure 11, the joining module 41 has a fluid supply / discharge unit 330 connected to a port on the side surface of the holding member 320, which supplies and discharges a deformation fluid to and from the deformation space 322. In this embodiment, the deformation fluid is air. However, the deformation fluid is not limited to air; an inert gas such as nitrogen (N2), or a liquid such as water or oil may be used.

[0088] The fluid supply and discharge section 330 is connected to a port of the holding member 320 and has a supply and discharge path 331 that extends outside the processing container 210. The fluid supply and discharge section 330 is equipped with a pump (pressure pump 332, pressure pump 333), a regulator 334, a valve 335, and a pressure sensor 336, arranged in order from the upstream side to the downstream side of the supply and discharge path 331.

[0089] The pressurizing pump 332 and the depressurizing pump 333 are, for example, branched upstream of the regulator 334 and can operate independently under the control of the control device 90. The pressurizing pump 332 supplies air to the holding member 320 to increase the internal pressure of the deformation space 322. The depressurizing pump 333 discharges air from the holding member 320 to reduce the internal pressure of the deformation space 322.

[0090] The regulator 334, for example, is an electro-pneumatic regulator, which adjusts the pressure of the air flowing through the supply and discharge path 331 to a target pressure commanded by the control device 90. The fluid supply and discharge section 330 is not limited to using only one regulator 334; for example, a regulator 334 may be applied to each of the pressurizing pump 332 and the depressurizing pump 333.

[0091] The valve 335 opens and closes the flow path in the supply and discharge path 331 under the control of the control device 90. For example, an air-operated valve (AOV) having the function of opening and closing the supply and discharge path 331 and the function of opening to the atmosphere to allow air to flow in and out can be applied as the valve 335. As a result, the deformed part 321 can be immediately restored by opening to the atmosphere when the deformation of the outer adsorption part 301 ends. Note that the application of valve 335 is not limited to one; for example, valve 335 may be applied to both the pressurizing pump 332 and the depressurizing pump 333.

[0092] The pressure sensor 336 detects the pressure of the air supplied to or discharged from the holding member 320 and transmits the detection information to the control device 90. Based on the detection information from the pressure sensor 336, the control device 90 adjusts the amount of air supplied to the deformation section 321 and closes the valve 335 at an appropriate timing. With the valve 335 closed, the deformation space 322 is maintained at a predetermined internal pressure, allowing the deformation state of the upper wall 324 to continue.

[0093] Furthermore, the bonding module 41 is equipped with a displacement sensor (measuring instrument) 340 located vertically above the lower chuck 231 to detect the amount of deformation of the outer suction part 301. The displacement sensor 340 is installed, for example, above the outer suction part 301 of the lower chuck 231, which is positioned at the substrate transfer location. The measurement method of the displacement sensor 340 is, for example, a confocal method, a spectral interferometry method, or a triangulation method. The light source of the displacement sensor 340 is an LED or a laser. The displacement sensor 340 is connected to the control device 90 and measures the amount of deformation of the outer suction part 301 when the lower wafer W2 is not on the suction surface 300, and transmits the measured measurement information to the control device 90.

[0094] The control device 90 can operate the deformable section 321 based on the measurement information measured by the displacement sensor 340. For example, the control device 90 stops the deformation of the deformable section 321 when the position of the outer suction section 301 is at the target position. When the position of the outer suction section 301 is not at the target position, the control device 90 deforms the deformable section 321 according to the amount and direction of the deviation from the target position. In Figure 11, one displacement sensor 340 is installed at a position opposite the outer suction section 301, but multiple displacement sensors 340 may be installed in the circumferential direction of the outer suction section 301. Alternatively, the first displacement gauge S3 applied to the upper chuck 230 may be used as the displacement sensor 340.

[0095] Furthermore, in this embodiment, when the bonding module 41 places the lower wafer W2 on the suction surface 300 of the lower chuck 231, it deforms the lower wafer W2 by utilizing the deformation inside the widthwise intermediate position 301c of the outer suction portion 301 (deformation space 322). Therefore, as shown in Figure 13, when the bonding module 41 holds the lower wafer W2 on the suction surface 300, it positions the lower wafer W2 such that the outer edge of the lower wafer W2 is located inside the widthwise intermediate position 301c of the outer suction portion 301. In Figure 13, the widthwise intermediate position 301c of the outer suction portion 301 is shown by a dashed line for convenience.

[0096] Since the outer edge of the lower wafer W2 is positioned inside the widthwise intermediate position 301c of the outer suction portion 301, the formation range of the deformation space 322 is designed to be the size corresponding to the dimensions of the lower wafer W2. For example, if the diameter of the lower wafer W2 is 300 mm, the diameter φI of the inner circumferential wall 326 of the deformation space 322 should be set in the range of 270 mm to 280 mm, and the diameter φO of the outer circumferential wall 325 of the deformation space 322 should be set in the range of 340 mm to 350 mm (see Figure 12). In this embodiment, the diameter φI of the inner circumferential wall 326 is 276 mm, and the diameter φO of the outer circumferential wall 325 is 346 mm. Therefore, the width of the outer suction portion 301 (deformation space 322) is 70 mm, and the widthwise intermediate position 301c of the outer suction portion 301 is 35 mm. The diameter from the center of the lower chuck 231 to the midpoint 301c in the width direction of the outer suction portion 301 is 276 mm + 35 mm = 311 mm. The boundary between the outer suction portion 301 and the inner suction portion 302 can be defined by the inner circumferential wall 326. The outer suction portion 301 may be considered as the entire holding member 320 radially outside the inner circumferential wall 326, or as the formation range of the deformation space 322 (between the outer circumferential wall 325 and the inner circumferential wall 326). Alternatively, the boundary between the outer suction portion 301 and the inner suction portion 302 may be defined by the support portion (protrusion 312) and the non-support portion (clearance 313) of the base member 310 (see Figure 11). For example, the ratio of the width of the outer suction portion 301 to the radius of the inner suction portion 302 is preferably set in the range of 1 / 5 to 3 / 5.

[0097] The bonding module 41 positions the outer edge of the lower wafer W2 inside the widthwise intermediate position 301c of the outer suction portion 301, thereby allowing the deformation shape inside the widthwise intermediate position 301c to influence the upper wafer W1 and lower wafer W2 in the case of the V-shaped or valley-shaped deformation of the deformation portion 321. For example, if the outer edge of the bonding surface W2j of the lower wafer W2 is elongated relative to the upper wafer W1, the deformation portion 321 (upper wall 324) of the deformation space 322 is bulged outward in order to shrink the bonding surface W2j inward (see also Figure 14(A)). Conversely, if the outer edge of the bonding surface W2j of the lower wafer W2 is contracted relative to the upper wafer W1, the deformation portion 321 (upper wall 324) of the deformation space 322 is recessed in order to extend the bonding surface W2j outward (see also Figure 14(B)). In this way, the bonding apparatus 1 can accurately correct the relative expansion and contraction occurring between the upper wafer W1 and the lower wafer W2 by utilizing the shape of the center side of the deformed outer suction portion 301.

[0098] The bonding apparatus 1 according to this embodiment is basically configured as described above, and its operation (method of holding the substrate) will be explained below with reference to Figure 15.

[0099] The control device 90 performs a process to appropriately adjust the shape of the lower chuck 231 when the lower wafer W2 is loaded into the lower chuck 231 during the manufacturing process of the bonded wafer T (step S111 in Figure 8) and the lower wafer W2 is held in the lower chuck 231. However, if the lower chuck 231 is deformed while the lower wafer W2 is held in place, effects such as friction on the back surface of the lower wafer W2 and changes in the amount of deformation may occur.

[0100] Therefore, the control device 90 performs shape adjustment on the lower chuck 231 when the lower wafer W2 is absent. Specifically, the control device 90 first determines whether or not the lower wafer W2 is present in the lower chuck 231 (step S121). For example, the control device 90 can determine the presence or absence of the lower wafer W2 by applying suction pressure to the suction surface 300 and monitoring the suction path and pressure fluctuations of the vacuum pumps 261a and 261b using sensors or the like.

[0101] Then, if the lower wafer W2 is in the lower chuck 231 (step S121: NO), the process proceeds to step S122. In step S122, the control device 90 notifies an error indicating the presence of the lower wafer W2 via a monitor (not shown) or the like. If the lower chuck 231 contains a bonded wafer T and has not yet been removed, the control device 90 may use the transport device 61 to remove the bonded wafer T. Alternatively, if the lower wafer W2 is present, the control device 90 may automatically remove the lower wafer W2 using the transport device 61 along with notifying an error, and then proceed to step S123.

[0102] On the other hand, if the lower wafer W2 is not in the lower chuck 231 (step S121: YES), the process proceeds to step S123. In step S123, the control device 90 operates the moving mechanism 290 to move the lower chuck 231 to the substrate transfer position.

[0103] Next, the control device 90 measures the height (vertical position) of the outer suction portion 301 of the lower chuck 231 using the displacement sensor 340 (step S124). This allows the control device 90 to recognize the current height of the outer suction portion 301.

[0104] Subsequently, the control device 90 determines whether the height of the outer suction part 301 is at the target position (step S125). This target position is calculated in advance before substrate processing by the control device 90 performing appropriate calculations based on the relative difference in the warping state of the upper wafer W1 and the lower wafer W2, after measuring the warping state (amount of warping, direction of warping) of the upper wafer W1 and the lower wafer W2 using the warping measuring device 5 (see Figure 1).

[0105] Then, if the position of the outer suction part 301 is not at the target position (step S125: NO), the control device 90 proceeds to step S126 and performs deformation operation of the deformation part 321. At this time, the control device 90 selectively performs a pressurizing process to increase the internal pressure of the deformation space 322 and a depressurizing process to decrease the internal pressure of the deformation space 322, according to the deformation direction and amount of the outer suction part 301 based on the relative difference in the warping state of the upper wafer W1 and the lower wafer W2.

[0106] For example, when pressurizing, air is supplied to the deformation space 322 by the fluid supply / discharge section 330, causing the upper wall 324 to bulge upward in the vertical direction, as shown in Figure 14(A). At this time, the upper wall 324 curves into an arc shape with the midpoint 301c in the width direction as its apex. Therefore, after the deformation of the lower chuck 231, the lower wafer W2, whose outer edge is adsorbed radially inward from the midpoint 301c in the width direction of the outer adsorption section 301, is held by the lower chuck 231 in a shape that is inclined vertically upward toward the radially outward direction.

[0107] As a result, for example, if the outer periphery of the bonding surface W2j of the lower wafer W2 is distorted such that it extends radially outward relative to the bonding surface W1j of the upper wafer W1, the lower wafer W2 can be held in such a way that it contracts radially inward when the lower wafer W2 is adsorbed. Alternatively, if the outer periphery of the bonding surface W1j of the upper wafer W1 is distorted such that it contracts radially inward relative to the bonding surface W2j of the lower wafer W2, the upper wafer W1 can be bonded in such a way that it extends radially outward during bonding.

[0108] On the other hand, when a depressurization process is performed, as shown in Figure 14(B), the fluid supply and discharge section 330 discharges air from the deformation space 322, causing the upper wall 324 to be recessed (contracted) vertically downward. At this time, the upper wall 324 curves into an arc shape with the widthwise intermediate position 301c as its bottom. Therefore, after the deformation of the lower chuck 231, the lower wafer W2, whose outer edge is adsorbed radially inward from the widthwise intermediate position 301c of the outer adsorption section 301, is held by the lower chuck 231 in a shape that is inclined vertically downward toward the radially outward direction.

[0109] As a result, for example, if the outer periphery of the bonding surface W2j of the lower wafer W2 is distorted such that it shrinks radially inward relative to the bonding surface W1j of the upper wafer W1, the lower wafer W2 can be held in a way that it stretches radially outward when the lower wafer W2 is adsorbed. Alternatively, if the outer periphery of the bonding surface W1j of the upper wafer W1 is distorted such that it stretches radially inward relative to the bonding surface W2j of the lower wafer W2, the upper wafer W1 can be bonded in a way that it shrinks radially inward during bonding.

[0110] Returning to Figure 15, the control device 90 monitors the position of the outer suction part 301 by repeating steps S124 and S125 during the deformation operation of the deformable part 321 in step S126. Then, in step S125, if the control device 90 determines that the position of the outer suction part 301 is at the target position (step S125: YES), it stops the deformation operation of the deformable part 321 and proceeds to step S127. If the outer suction part 301 is initially at the target position as measured by the displacement sensor 340, the device proceeds to step S127 without performing the deformation operation of the deformable part 321.

[0111] In step S127, the control device 90 receives the lower wafer W2 from the transport device 61 (see Figure 1) onto the lower chuck 231, whose outer suction portion 301 has been adjusted to the target position. When receiving the lower wafer W2, the control device 90 uses vacuum pumps 261a and 261b to exert suction pressure on the suction surface 300, causing the lower wafer W2 to be adsorbed onto the outer suction portion 301 and the inner suction portion 302. As described above, if the outer suction portion 301 is bulging or contracting, the lower wafer W2 is held in a deformed state around its outer periphery. Then, the bonding device 1 moves the lower chuck 231 to the bonding position with the lower wafer W2 in its deformed state (step S112 in Figure 8) and bonds it with the upper wafer W1 (steps S113 and S114 in Figure 8). As a result, the bonding device 1 can produce a bonded wafer T with reduced deviation of the reference point at the outer periphery.

[0112] As described above, the bonding apparatus 1 according to this embodiment can appropriately correct the distortion of the outer periphery of the lower wafer W2 (and upper wafer W1) by deforming the outer suction part 301 relative to the inner suction part 302 using the deformation part 321. As a result, for example, if a large distortion occurs in the outer periphery of the bonding surface W2j of the lower wafer W2 relative to the outer periphery of the bonding surface W1j of the upper wafer W1, it becomes possible to sufficiently correct the distortion of the lower wafer W2 and bond it to the upper wafer W1. As a result, the bonding apparatus 1 can produce a bonded wafer T with reduced misalignment between the reference points P11~P13 of the upper wafer W1 and the reference points P21~P23 of the lower wafer W2.

[0113] In particular, the bonding apparatus 1 according to the first embodiment can easily deform the outer suction part 301 by supplying and discharging air to and from the deformation space 322, thereby deforming (expanding and contracting) the outer suction part 301. Since the deformation part 321 can be deformed by the deformation space 322 without complicating the structure of the holding member 320, it is possible to make the lower chuck 231 thinner. In addition, since the surface of the outer suction part 301 (e.g., the top surface) and the surface of the inner suction part 302 (e.g., the top surface) are flush and continuous in the bonding apparatus 1, the lower wafer W2 can be stably supported without rattling at the boundary between the outer suction part 301 and the inner suction part 302, even in a structure that deforms the outer suction part 301. Furthermore, the control device 90 can reliably deform the outer suction part 301 to the target position by deforming the outer suction part 301 while measuring the position of the outer suction part 301 with the displacement sensor 340.

[0114] It should be noted that the bonding apparatus 1 and the method for holding the substrate are not limited to the above configuration, and various modifications are possible. For example, the substrate processing apparatus is not limited to the bonding apparatus 1, and may be applied to an apparatus that includes a chuck (holding part) for holding the substrate and performs substrate processing related to the in-plane uniformity of the substrate in substrate processing. As an example, in a film deposition apparatus (substrate processing apparatus), the film deposition process (substrate processing) can be performed with high precision by improving the distortion of the outer peripheral part of the substrate by deformation of the outer suction part 301.

[0115] Furthermore, as shown in Figure 14(C), the bonding apparatus 1 may position the outer edge of the lower wafer W2 outside the widthwise intermediate position 301c of the outer suction portion 301. If the expansion and contraction of the lower wafer W2 differs depending on its radial position due to structural factors of the lower wafer W2, the deformation of the outer suction portion 301 can be used to perform both contraction and expansion corrections on the bonding surface W2j, thereby further optimizing the correction of the outer periphery.

[0116] For example, as shown in Figure 16, the deformation section 321 that deforms the outer suction section 301 may have a plurality of divided deformation spaces 322A along the circumferential direction of the lower chuck 231, and a configuration in which air is supplied and discharged for each of the deformation spaces 322A may be used. This allows the lower chuck 231 to individually adjust the amount of circumferential deformation of the outer suction section 301 according to the strain of the lower wafer W2 (or upper wafer W1). For example, if the bonding surface W2j in the X-axis direction is stretching while the bonding surface W2j in the Y-axis direction is contracting, the outer suction section 301 can pressurize the deformation space 322A in the X-axis direction and depressurize the deformation space 322A in the Y-axis direction. In other words, the bonding apparatus 1 can appropriately correct according to the relative difference in expansion and contraction (strain) of the lower wafer W2 and the upper wafer W1. Although Figure 16 shows a configuration divided into eight deformation spaces 322A, the number of divisions and the volume of each space can of course be freely designed.

[0117] [Second Embodiment] Next, the lower chuck 231A according to the second embodiment will be described with reference to Figures 17 and 18. This lower chuck 231A differs from the lower chuck 231 according to the first embodiment in that the deformation of the outer suction part 301 is performed mechanically by a mechanism part 350 having an actuator (drive source), without supplying or discharging a fluid for deformation.

[0118] Specifically, the holding member 320 of the lower chuck 231A has a disc-shaped inner support portion 327 and a plurality of arc-shaped outer support portions 328 provided adjacent to the outer side of the inner support portion 327. For example, the inner support portion 327 and the outer support portions 328 are made of separate components, and the two portions are fixed together by appropriate fixing means such as screws, thereby forming a substantially flat suction surface 300 with the upper surfaces of both portions. The holding member 320 may also be configured by integrally molding the inner support portion 327 and the outer support portions 328.

[0119] The outer support portion 328 is made of a material having a smaller modulus of elasticity than the inner support portion 327. In a side cross-sectional view along the vertical direction, the outer support portion 328 has an L-shape, with a vertical portion 328a fixed to the inner support portion 327 and a horizontal portion 328b protruding horizontally from the upper end of the vertical portion 328a. The upper surface of the horizontal portion 328b forms the outer suction portion 301 of the suction surface 300, and the upper surface of the inner support portion 327 forms the inner suction portion 302 of the suction surface 300. In other words, the lower chuck 231A has a deformation portion 321A that deforms the horizontal portion 328b of the outer support portion 328 in the height direction.

[0120] The deformable portion 321A includes a bracket 351, a piezo actuator 352 for operating the outer support portion 328, and a control sensor 353 for detecting the position of the outer support portion 328.

[0121] The bracket 351 is fixed to the vertical portion 328a of the outer support portion 328. The bracket 351 holds the piezo actuator 352 and the control sensor 353 in the cutout space of the outer support portion 328.

[0122] The piezo actuator 352 advances the pin portion 352p based on the supply of power to a piezoelectric element (not shown), and retracts the pin portion 352p when the power supply to the piezoelectric element is stopped. This piezo actuator 352 can control the position of the pin portion 352p with high precision in the range of several nanometers to several hundred micrometers depending on the applied power.

[0123] The pin portion 352p protrudes vertically from the body of the piezo actuator 352. The upper end of the pin portion 352p is fixed to the lateral portion 328b of the opposing outer support portion 328 by appropriate fixing means (screw fastening, welding, etc.). Therefore, the lateral portion 328b curves vertically upward in the radially outward direction as the pin portion 352p rises, while curving vertically downward in the radially outward direction as the pin portion 352p descends.

[0124] The control sensor 353 is a sensor that measures the vertical position of the outermost periphery of the lateral portion 328b and is connected to the control device 90 in a manner that enables information communication. Examples of this type of control sensor 353 include a capacitive sensor, an optical displacement sensor, a strain sensor, etc. When the piezo actuator 352 is driven, the control device 90 controls the power supplied to the piezo actuator 352 based on the measurement information detected by the control sensor 353.

[0125] Furthermore, the lower chuck 231A may be equipped with a displacement sensor 340 located vertically above the lateral portion 328b of the outer support portion 328, and the displacement sensor 340 may be used to measure the position of the lateral portion 328b or the position of the lower wafer W2. The control device 90 can adjust the power supplied to the piezo actuator 352 based on the measurement information from the displacement sensor 340.

[0126] As shown in Figure 18, the lower chuck 231A is equipped with an outer support portion 328 divided into multiple sections along the circumferential direction of the outer suction portion 301. Slits 329 extending radially are formed between adjacent outer support portions 328. The slits 329 reach the inner support portion 327, completely separating each outer support portion 328. The lower chuck 231A is equipped with a deformable portion 321A (bracket 351, piezo actuator 352, control sensor 353) for each of the multiple outer support portions 328, allowing each lateral portion 328b to be deformed independently.

[0127] Thus, the joining device 1 can appropriately deform each outer suction part 301 by providing multiple mechanisms 350 that deform each outer support part 328 along the circumferential direction of the outer suction part 301. In particular, by applying a piezo actuator 352 as the drive source for the mechanism 350, each outer suction part 301 can be deformed with high precision under the control of the control device 90.

[0128] Furthermore, the lower chuck 231A may have an outer suction portion 301 that is continuous along the circumferential direction, and by operating multiple deformation portions 321A simultaneously, the entire circumferential direction of the outer suction portion 301 may be deformed as a single unit. Also, the deformation portion 321A that deforms the lateral portion 328b of the outer support portion 328 is not limited to the mechanism shown in Figure 17, but can take various configurations. Several other configurations of the deformation portion 321A will be described below with reference to Figure 19.

[0129] The deformable section 321B (mechanism section 350A) shown in Figure 19(A) uses a piezo actuator 352A with a built-in strain sensor 352s. The strain sensor 352s can perform the same role as the control sensor 353 by detecting the displacement of the pin section 352p and transmitting that information to the control device 90. As a result, the deformable section 321B can omit the control sensor 353. Therefore, the deformable section 321B can use a simple bracket 351 to fix the piezo actuator 352A, further simplifying the overall configuration.

[0130] The deformable section 321C (mechanism section 350B) shown in Figure 19(B) is equipped with a plurality of piezo actuators 352A along the radial direction of the outer suction section 301. In this case, the bracket 351 is formed to have a plurality of recesses to accommodate each piezo actuator 352A. Each piezo actuator 352A has a built-in strain sensor 352s that can detect the displacement of each pin section 352p. The control device 90 can individually control the displacement of each piezo actuator 352A arranged in the radial direction, thereby increasing the deformation of the outer suction section 301 or causing it to take on various shapes, such as curving the outer suction section 301 into a V-shape or a valley shape.

[0131] The deformable section 321D shown in Figure 19(C) uses a linear mechanism 354 instead of the mechanism section 350 which has a piezo actuator 352. Specifically, the deformable section 321D holds the housing 355 of the linear mechanism 354 with a bracket 351, and the housing 355 contains a linear motor 356, a linear guide 357, and a linear scale 358.

[0132] The linear motor 356 is connected to the control device 90 and displaces on the linear guide 357 based on the power supplied from the control device 90. The linear guide 357 extends along the vertical direction. Therefore, the deformable part 321D raises and lowers (displaces) the pin portion 356p protruding from the linear motor 356, thereby deforming the lateral portion 328b of the outer support portion 328 to which the pin portion 356p is connected. The control device 90 can appropriately adjust the deformation direction and amount of the lateral portion 328b by displacing the linear motor 356 while detecting the position of the linear motor 356 using the linear scale 358.

[0133] The deformable section 321E shown in Figure 19(D) includes a linear guide 357, a linear scale 358, a servo motor 359, and a ball screw mechanism 360 within the housing 355 as another linear mechanism 354A. That is, this linear mechanism 354A adjusts the power pulses supplied to the servo motor 359 and converts the rotation of the servo motor 359 into linear motion in the ball screw mechanism 360, thereby causing the pin portion 360p connected to the movable body of the ball screw mechanism 360 to move forward and backward. Even in this case, the control device 90 can appropriately adjust the deformation direction and amount of the lateral portion 328b.

[0134] The substrate processing apparatus (bonding apparatus 1) and substrate holding method according to the embodiments disclosed herein are illustrative in all respects and are not restrictive. The embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be otherwise configured and combined in a non-consistent manner. [Explanation of Symbols]

[0135] 1. Bonding device (substrate processing device) 231 Lower zipper (holding part) 300 Adsorption surface 301 Outside suction part 302 Inner suction part 321, 321A~321E Deformed section W1 Upper wafer W2 lower wafer

Claims

1. It is equipped with a holding part that holds the substrate by adsorption using an adsorption surface, The adsorption surface includes an outer adsorption portion that adsorbs the outer periphery of the substrate and an inner adsorption portion that adsorbs the portion of the substrate that is inward from the outer periphery. The holding portion has a deformation portion that deforms the outer suction portion relative to the inner suction portion, The deformable portion has a deformation space inside the holding portion located at the outer suction portion. The deformation portion expands the outer adsorption portion relative to the inner adsorption portion by supplying fluid to the deformation space, or contracts the outer adsorption portion relative to the inner adsorption portion by discharging the fluid from inside the holding portion. Circuit board processing equipment.

2. The holding portion comprises a holding member having the suction surface and a base member supporting the back surface of the holding member. The base member supports the back surface of the inner suction portion, but does not support the back surface of the outer suction portion. The substrate processing apparatus according to claim 1.

3. The thickness between the surface of the outer adsorption portion and the deformation space is thinner than the thickness between the back surface of the outer adsorption portion and the deformation space. The substrate processing apparatus according to claim 1.

4. The deformation space is continuous in an annular shape along the circumferential direction of the holding portion. The substrate processing apparatus according to claim 1.

5. A holding part that holds a substrate by adsorption using an adsorption surface, The adsorption surface includes an outer adsorption portion that adsorbs the outer periphery of the substrate and an inner adsorption portion that adsorbs the portion of the substrate that is inward from the outer periphery. The holding portion has a deformation portion that deforms the outer suction portion relative to the inner suction portion, With the center of the adsorption surface and the center of the substrate aligned and the substrate attached to the adsorption surface, the midpoint of the deformation portion in the width direction is located radially outward from the outer edge of the substrate. Circuit board processing equipment.

6. A holding part that holds a substrate by adsorption using an adsorption surface, The adsorption surface includes an outer adsorption portion that adsorbs the outer periphery of the substrate and an inner adsorption portion that adsorbs the portion of the substrate that is inward from the outer periphery. The holding portion has a deformation portion that deforms the outer suction portion relative to the inner suction portion, A measuring instrument for measuring the position of the outer adsorption portion, The system comprises a control unit that deforms the deformable part based on the measurement information measured by the measuring instrument, The control unit, When it is determined that the measured position of the outer suction part is at the target position, the deformation of the deformable part is stopped. Circuit board processing equipment.

7. The control unit deforms the deformation part if the measured position of the outer suction part is not at the target position. The substrate processing apparatus according to claim 6.

8. The deformation portion includes an outer support portion that contacts the substrate in the outer suction portion, and a mechanism portion connected to the outer support portion that deforms the outer support portion. A substrate processing apparatus according to any one of claims 5 to 7.

9. The mechanism includes a piezo actuator as a drive source for raising and lowering the outer support portion. The substrate processing apparatus according to claim 8.

10. The surface of the outer adsorption portion and the surface of the inner adsorption portion are continuous and flush with each other. A substrate processing apparatus according to any one of claims 1 to 7.

11. The outer adsorption portion is divided into multiple sections along the circumferential direction of the holding portion. A substrate processing apparatus according to any one of claims 1 to 3 or 5 to 7.

12. The substrate processing apparatus is a bonding apparatus that joins the substrate held by the holding part with another substrate positioned opposite to the said substrate. A substrate processing apparatus according to any one of claims 1 to 7.

13. A method for holding a substrate, comprising a holding portion having an adsorption surface that includes an outer adsorption portion for adsorbing the outer periphery of the substrate and an inner adsorption portion for adsorbing the portion of the substrate inside the outer periphery, A step of deforming the outer suction portion relative to the inner suction portion by a deformation portion provided in the holding portion, The process includes a step of adsorbing the substrate by the outer adsorption portion and the inner adsorption portion after the outer adsorption portion has been deformed. Method for holding the circuit board.

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