SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD

Abstract

To provide a technique for efficiently adsorbing a warped substrate.SOLUTION: A substrate processing apparatus includes a holding unit, a suction pressure generating unit, and a control unit. The holding unit includes a first circular region and a second annular region arranged outside the first region on the suction surface for sucking a substrate. The suction pressure generating unit causes a first portion which is a part in the circumferential direction of the first region and the second region, and a second portion which is a part of the other circumferential direction of the second region to individually generate suction pressure. The control unit controls the suction pressure generation unit. The control unit generates a suction pressure in the first region, generates a suction pressure in the first portion of the second region, and generates a suction pressure in the second portion of the second region in this order.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present disclosure relates to a substrate processing apparatus and a substrate processing method. [Background technology]

[0002] The bonding device described in Patent Document 1 includes an upper chuck that adsorbs the upper substrate from above and a lower chuck that adsorbs the lower substrate from below, and bonds the two substrates face to face. Specifically, the bonding device first presses down the center of the substrate adsorbed to the upper chuck so that it contacts the center of the substrate adsorbed to the lower chuck. This bonds the centers of the two substrates together by intermolecular forces or the like. Next, the bonding device expands the bonded region of the two substrates from the center to the periphery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-095579 A Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides a technique for efficiently adsorbing a warped substrate. [Means for solving the problem]

[0005] A substrate processing apparatus according to an aspect of the present disclosure includes a holding unit, a suction pressure generating unit, and a control unit. The holding unit has an adsorption surface for adsorbing a substrate, the adsorption pressure generating unit including a circular first region and an annular second region disposed outside the first region. The adsorption pressure generating unit generates adsorption pressures individually in the first region, a first portion that is a circumferential part of the second region, and a second portion that is another circumferential part of the second region. The control unit controls the adsorption pressure generating unit. Immediately before the control unit generates a suction pressure on the suction surface, the substrate is warped, and the distance between the second portion of the second region and the substrate is greater than the distance between the first portion of the second region and the substrate. The suction surface includes a first virtual line passing through a center of the suction surface, and a second virtual line perpendicular to the first virtual line at the center. Immediately before the control unit generates a suction pressure on the suction surface, the distance between the suction surface and the substrate increases as the first virtual line approaches the center, and the distance between the suction surface and the substrate increases as the second virtual line moves away from the center. The first portion of the second region is disposed on the first virtual line, and the second portion of the second region is disposed on the second virtual line. The suction surface further includes an annular peripheral region outside the second region. The suction pressure generating unit generates suction pressure individually in a third portion, which is a circumferential part of the peripheral region, and a fourth portion, which is another circumferential part of the peripheral region. The third portion of the peripheral region is disposed on the first virtual straight line, and the fourth portion of the peripheral region is disposed on the second virtual straight line. The control unit executes the following in this order: generating a suction pressure in the first region, generating a suction pressure in the first portion of the second region, generating a suction pressure in the third portion of the peripheral region, generating a suction pressure in the second portion of the second region, and generating a suction pressure in the fourth portion of the peripheral region. After generating a suction pressure on the entire suction surface, the control unit temporarily cancels generation of the suction pressure in the third portion of the peripheral region while generating a suction pressure in the fourth portion of the peripheral region, and then generates a suction pressure again. Effect of the Invention

[0006] According to one aspect of the present disclosure, the warped substrate can be efficiently sucked by shifting the timing at which the suction pressure is generated between the first portion and the second portion of the second region. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a bonding device according to one embodiment. [Diagram 2] FIG. 2 is a side view of the joining device of FIG. [Diagram 3] FIG. 3 is a side view showing an example of the first substrate and the second substrate. [Figure 4] FIG. 4 is a flow chart illustrating a bonding method according to one embodiment. [Diagram 5] FIG. 5 is a side view showing an example of the first position adjustment device. [Figure 6] FIG. 6 is a plan view showing an example of a joining module. [Figure 7] FIG. 7 is a side view of the interface module of FIG. [Figure 8] FIG. 8 is a cross-sectional view showing an example of an upper chuck and a lower chuck. [Figure 9] FIG. 9 is a flowchart showing the details of step S109 in FIG. [Figure 10] FIG. 10(A) is a side view showing an example of the operation in step S112, FIG. 10(B) is a side view showing the operation following FIG. 10(A), and FIG. 10(C) is a side view showing the operation following FIG. 10(B). [Figure 11] FIG. 11(A) is a cross-sectional view showing an example of the operation in step S113, FIG. 11(B) is a cross-sectional view showing an example of the operation in step S114, and FIG. 11(C) is a cross-sectional view showing the operation following FIG. 11(B). [Figure 12] FIG. 12 is a plan view showing an example of a section of the suction surface of the lower chuck. [Figure 13] FIG. 13 is a diagram illustrating an example of the suction pressure generating section. [Figure 14] Figure 14(A) is an oblique view showing a first example of warping of the lower wafer, Figure 14(B) is a diagram showing the distance between the suction surface and the lower wafer on a first virtual line, and Figure 14(C) is a diagram showing the distance between the suction surface and the lower wafer on a second virtual line. [Figure 15] FIG. 15(A) is a perspective view showing a first example of the order in which suction pressure is generated when suctioning the lower wafer shown in FIG. 14, and FIG. 15(B) is a perspective view showing a first example of the order in which suction pressure is generated following FIG. 15(A). [Figure 16] FIG. 16(A) is a perspective view showing a second example of the order in which suction pressure is generated when suctioning the lower wafer shown in FIG. 14, and FIG. 16(B) is a perspective view showing a second example of the order in which suction pressure is generated following FIG. 16(A). [Figure 17] Figure 17(A) is an oblique view showing a second example of warping of the lower wafer, Figure 17(B) is a diagram showing the distance between the suction surface and the lower wafer on the first virtual line, and Figure 17(C) is a diagram showing the distance between the suction surface and the lower wafer on the second virtual line. [Figure 18] FIG. 18(A) is a perspective view showing an example of the order in which suction pressure is generated when suctioning the lower wafer shown in FIG. 17, and FIG. 18(B) is a perspective view showing an example of the order in which suction pressure is generated following FIG. 18(A). [Figure 19] FIG. 19(A) is a cross-sectional view showing a first example of a local suction section, FIG. 19(B) is a cross-sectional view showing a second example of a local suction section, and FIG. 19(C) is a cross-sectional view showing a third example of a local suction section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding configurations are denoted by the same reference numerals, and the description may be omitted. In addition, the X-axis direction, the Y-axis direction, and the Z-axis direction are mutually perpendicular directions, the X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is vertical directions.

[0009] First, a bonding apparatus 1 according to the present embodiment will be described with reference to Fig. 1 and Fig. 2. Note that the substrate processing apparatus of the present disclosure is not limited to the bonding apparatus 1, and may be, for example, an exposure apparatus or a temperature adjustment apparatus. The exposure apparatus transfers a mask pattern onto the substrate. The temperature adjustment apparatus adjusts the temperature of the substrate. The substrate processing apparatus may include a holder for holding a substrate, and may process the substrate held by the holder.

[0010] As shown in FIG. 3, the bonding apparatus 1 bonds a first substrate W1 and a second substrate W2 to produce a laminated substrate T. At least one of the first substrate W1 and the second substrate W2 is a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer on which a plurality of electronic circuits are formed. One of the first substrate W1 and the second substrate W2 may be a bare wafer on which no electronic circuits are formed. The first substrate W1 and the second substrate W2 have approximately the same diameter. The compound semiconductor wafer is not particularly limited, but may be, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer.

[0011] 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 overlapped substrate T may be referred to as the "overlapped wafer T". As shown in Fig. 3, of the surfaces of the upper wafer W1, the surface that is to be joined to the lower wafer W2 is referred to as the "joining surface W1j", and the surface opposite the bonding surface W1j is referred to as the "non-bonding surface W1n". Also, of the surfaces of the lower wafer W2, the surface that is to be joined to the upper wafer W1 is referred to as the "joining surface W2j", and the surface opposite the bonding surface W2j is referred to as the "non-bonding surface W2n".

[0012] 1, the bonding apparatus 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are arranged in the positive direction of the X-axis in the order of the loading / unloading station 2 and the processing station 3. The loading / unloading station 2 and the processing station 3 are connected together.

[0013] The carry-in / out station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 includes a plurality of mounting plates 11. Cassettes CS1, CS2, and CS3, which accommodate a plurality of substrates (e.g., 25 substrates) in a horizontal state, are mounted on each of the mounting plates 11. The cassette CS1 is a cassette that accommodates an upper wafer W1, the cassette CS2 is a cassette that accommodates a lower wafer W2, and the cassette CS3 is a cassette that accommodates a laminated wafer T. In the cassettes CS1 and CS2, the upper wafer W1 and the lower wafer W2 are accommodated with their bonding surfaces W1j and W2j facing upwards and aligned in the same direction.

[0014] The transfer area 20 is disposed adjacent to the mounting table 10 on the positive side of the X-axis. The transfer area 20 is provided with a transfer path 21 extending in the Y-axis direction and a transfer device 22 movable along the transfer path 21. The transfer device 22 is movable also in the X-axis direction and rotatable about the Z-axis, and transfers the upper wafer W1, lower wafer W2, and overlapped wafer T between cassettes CS1 to CS3 placed on the mounting table 10 and a third processing block PB3 of the processing station 3, which will be described later.

[0015] The number of cassettes CS1 to CS3 placed on the mounting table 10 is not limited to that shown in the figure. In addition to the cassettes CS1, CS2, and CS3, a cassette for recovering defective substrates or the like may be placed on the mounting table 10.

[0016] For example, three processing blocks PB1, PB2, and PB3 are provided in the processing station 3. For example, a first processing block PB1 is provided on the rear side (positive Y-axis side in FIG. 1) of the processing station 3, and a second processing block PB2 is provided on the front side (negative Y-axis side in FIG. 1) of the processing station 3. In addition, a third processing block PB3 is provided on the loading / unloading station 2 side of the processing station 3 (negative X-axis side in FIG. 1).

[0017] A transfer region 60 is formed in an area surrounded by the first processing block PB1 to the third processing block PB3. A transfer device 61 is disposed in the transfer region 60. The transfer device 61 has a transfer arm that is movable, for example, in the vertical direction, the horizontal direction, and around the vertical axis.

[0018] The transfer device 61 moves within the transfer region 60 to transfer the upper wafer W1, the lower wafer W2, and the overlapping wafer T to predetermined devices within the first processing block PB1, the second processing block PB2, and the third processing block PB3 adjacent to the transfer region 60.

[0019] In the first processing block PB1, for example, a surface modification device 33 and a surface hydrophilization device 34 are arranged. 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.

[0020] For example, the surface modification device 33 breaks the SiO2 bonds on the bonding surfaces W1j and W2j to form dangling bonds of Si, enabling subsequent hydrophilization. In the surface modification device 33, for example, oxygen gas, which is a processing gas, is excited to be plasmatized and ionized in a reduced pressure atmosphere. Then, the oxygen ions are irradiated onto the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2, whereby the bonding surfaces W1j and W2j are plasma-processed and modified. The processing gas is not limited to oxygen gas, and may be, for example, nitrogen gas.

[0021] The surface hydrophilization device 34 hydrophilizes the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 with a hydrophilization treatment liquid such as pure water. The surface hydrophilization device 34 also has a role of cleaning the bonding surfaces W1j, W2j. In the surface hydrophilization device 34, for example, while rotating the upper wafer W1 or the lower wafer W2 held by a spin chuck, pure water is supplied onto the upper wafer W1 or the lower wafer W2. As a result, the pure water diffuses on the bonding surfaces W1j, W2j, and OH groups are attached to the dangling bonds of Si, thereby hydrophilizing the bonding surfaces W1j, W2j.

[0022] In the second processing block PB2, for example, a bonding module 41 is disposed. The bonding module 41 bonds the hydrophilized upper wafer W1 and the lower wafer W2 to produce a laminated wafer T. The first temperature adjustment device 42 adjusts the temperature distribution of the upper wafer W1 before bonding, i.e., before contact with the lower wafer W2. The second temperature adjustment device 43 adjusts the temperature distribution of the lower wafer W2 before bonding, i.e., before contact with the upper wafer W1. Note that in this embodiment, the first temperature adjustment device 42 and the second temperature adjustment device 43 are provided separately from the bonding module 41, but may be provided as part of the bonding module 41.

[0023] In the third processing block PB3, for example, a first position adjustment device 51, a second position adjustment device 52, and transition devices 53 and 54 are stacked in this order from top to bottom (see FIG. 2). The locations of the devices in the third processing block PB3 are not limited to those shown in FIG. 2. The first position adjustment device 51 adjusts the horizontal orientation of the upper wafer W1, and also turns the upper wafer W1 upside down 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 upper wafer W1 is temporarily placed in the transition device 53. In addition, the lower wafer W2 and the overlapped wafer T are temporarily placed in the transition device 54.

[0024] The bonding apparatus 1 includes a control device 90. The control device 90 is, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores programs that control various processes executed in the bonding apparatus 1. The control device 90 controls the operation of the bonding apparatus 1 by having the CPU 91 execute the programs stored in the storage medium 92.

[0025] Next, the joining method of this embodiment will be described with reference to Fig. 4. Steps S101 to S109 shown in Fig. 4 are performed under the control of the control device 90.

[0026] First, the cassette CS1 accommodating a plurality of upper wafers W1, the cassette CS2 accommodating a plurality of lower wafers W2, and the empty cassette CS3 are placed on the placement table 10 of the carry-in / out station 2.

[0027] Next, the transfer device 22 takes out the upper wafer W1 in the cassette CS1 and transfers it to the transition device 53 in the third processing block PB3 of the processing station 3. Thereafter, the transfer device 61 takes out the upper wafer W1 from the transition device 53 and transfers it to the surface modification device 33 in the first processing block PB1.

[0028] Next, the surface modification device 33 modifies the bonding surface W1j of the upper wafer W1 (step S101). The modification of the bonding surface W1j is performed with the bonding surface W1j facing upward. Thereafter, the transfer device 61 takes out the upper wafer W1 from the surface modification device 33 and transfers it to the surface hydrophilization device .

[0029] Next, the surface hydrophilization device 34 hydrophilizes the bonding surface W1j of the upper wafer W1 (step S102). The hydrophilization of the bonding surface W1j is performed with the bonding surface W1j facing upward. Thereafter, the transfer device 61 takes out the upper wafer W1 from the surface hydrophilization device 34 and transfers it to the first position adjustment device 51 of the third processing block PB3.

[0030] Next, the first position adjustment device 51 adjusts the horizontal orientation of the upper wafer W1 and turns the upper wafer W1 upside down (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 faces downward. Thereafter, the transfer device 61 takes out the upper wafer W1 from the first position adjustment device 51 and transfers it to the first temperature adjustment device 42 in the second processing block PB2.

[0031] Next, the first temperature adjustment device 42 adjusts the temperature of the upper wafer W1 (step S104). The temperature adjustment of the upper wafer W1 is performed with the bonding surface W1j of the upper wafer W1 facing downward. Thereafter, the transfer device 61 takes out the upper wafer W1 from the first temperature adjustment device 42 and transfers it to the bonding module 41.

[0032] In parallel with the above-mentioned processing for the upper wafer W1, the following processing for the lower wafer W2 is performed. First, the transfer device 22 takes out the lower wafer W2 from the cassette CS2 and transfers it to the transition device 54 in the third processing block PB3 of the processing station 3. Then, the transfer device 61 takes out the lower wafer W2 from the transition device 54 and transfers it to the surface modification device 33 in the first processing block PB1.

[0033] Next, the surface modification device 33 modifies the bonding surface W2j of the lower wafer W2 (step S105). The modification of the bonding surface W2j is performed with the bonding surface W2j facing upward. Thereafter, the transfer device 61 takes out the lower wafer W2 from the surface modification device 33 and transfers it to the surface hydrophilization device .

[0034] Next, the surface hydrophilization device 34 hydrophilizes the bonding surface W2j of the lower wafer W2 (step S106). The hydrophilization of the bonding surface W2j is performed with the bonding surface W2j facing upward. Thereafter, the transfer device 61 takes out the lower wafer W2 from the surface hydrophilization device 34 and transfers it to the second position adjustment device 52 of the third processing block PB3.

[0035] Next, the second position adjustment device 52 adjusts the horizontal orientation of the lower wafer W2 (step S107). As a result, the notch of the lower wafer W2 is oriented in a predetermined direction. Thereafter, the transfer device 61 takes out the lower wafer W2 from the second position adjustment device 52 and transfers it to the second temperature adjustment device 43 in the second processing block PB2.

[0036] Next, the second temperature control device 43 adjusts the temperature of the lower wafer W2 (step S108). The temperature control of the lower wafer W2 is performed with the bonding surface W2j of the lower wafer W2 facing upward. Thereafter, the transfer device 61 takes out the lower wafer W2 from the second temperature control device 43 and transfers it to the bonding module 41.

[0037] Next, the bonding module 41 bonds the upper wafer W1 and the lower wafer W2 to manufacture the overlapped wafer T (step S109). Thereafter, the transfer device 61 takes out the overlapped wafer T from the bonding module 41 and transfers it to the transition device 54 in the third processing block PB3.

[0038] Finally, the transfer device 22 takes out the overlapped wafer T from the transition device 54, and transfers it to the cassette CS3 on the mounting table 10. This completes a series of processes.

[0039] Next, an example of the first position adjustment device 51 will be described with reference to Fig. 5. The second position adjustment device 52 is configured similarly to the first position adjustment device 51 except that it does not have the base inversion unit 51d, and therefore a description thereof will be omitted.

[0040] The first position adjustment device 51 has a base 51a, a holder 51b that suction-holds and rotates the upper wafer W1, and a detector 51c that detects the positions of the notches of the upper wafer W1 and the lower wafer W2. While the holder 51b suction-holds and rotates the upper wafer W1, the detector 51c detects the position of the notch of the upper wafer W1, thereby adjusting the position of the notch and adjusting the horizontal orientation of the upper wafer W1.

[0041] The first position adjustment device 51 also has a base inverting unit 51d that inverts the base 51a. The base inverting unit 51d is equipped with, for example, a motor, and inverts the base 51a upside down, thereby inverting the upper wafer W1 held by the holder 51b upside down. As a result, the bonding surface W1j of the upper wafer W1 faces downward.

[0042] Next, an example of the bonding module 41 will be described with reference to Fig. 6 to Fig. 8. As shown in Fig. 6, the bonding module 41 has a processing container 210 whose interior can be sealed. A loading / unloading port 211 is formed on a side surface of the processing container 210 facing the transfer area 60, and an opening / closing shutter 212 is provided at the loading / unloading port 211. The upper wafer W1, the lower wafer W2, and the overlapped wafer T are loaded and unloaded through the loading / unloading port 211.

[0043] 7, an upper chuck 230 and a lower chuck 231 are provided inside the processing vessel 210. The upper chuck 230 holds the upper wafer W1 from above with the bonding surface W1j of the upper wafer W1 facing downward. The lower chuck 231 is provided below the upper chuck 230 and holds the lower wafer W2 from below with the bonding surface W2j of the lower wafer W2 facing upward.

[0044] The upper chuck 230 is supported by a support member 280 provided on the ceiling surface of the processing vessel 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.

[0045] As described below, the first lower chuck moving part 291 moves the lower chuck 231 in the horizontal direction (Y-axis direction). Moreover, the first lower chuck moving part 291 is configured to be capable of moving the lower chuck 231 in the vertical direction and to rotate the lower chuck 231 about a vertical axis.

[0046] The first lower chuck moving part 291 is provided on the lower surface side of the first lower chuck moving part 291 and is attached to a pair of rails 295 extending in the horizontal direction (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 a second lower chuck moving part 296.

[0047] The second lower chuck moving part 296 is provided on the lower surface side of the second lower chuck moving part 296 and is attached to a pair of rails 297 extending in the horizontal direction (X-axis direction). The second lower chuck moving part 296 is configured to be movable along the rails 297, that is, to move the lower chuck 231 in the horizontal direction (X-axis direction). The pair of rails 297 are provided on a mounting table 298 provided on the bottom surface of the processing vessel 210.

[0048] The first lower chuck moving part 291 and the second lower chuck moving part 296 constitute a moving mechanism 290. The moving mechanism 290 moves the relative positions of the upper chuck 230 and the lower chuck 231 between a substrate transfer position and a joining position.

[0049] The substrate transfer position is a position where the upper chuck 230 receives the upper wafer W1 from the transfer device 61, the lower chuck 231 receives the lower wafer W2 from the transfer device 61, and the lower chuck 231 transfers the overlapped wafer T to the transfer device 61. The substrate transfer position is a position where the overlapped wafer T produced in the nth (n is a natural number equal to or greater than 1) bonding is successively carried out, and the upper wafer W1 and lower wafer W2 to be bonded in the n+1th bonding are carried in. The substrate transfer position is, for example, a position shown in FIGS. 6 and 7.

[0050] The transfer device 61 enters directly below the upper chuck 230 when transferring the upper wafer W1 to the upper chuck 230. The transfer device 61 also enters directly above the lower chuck 231 when receiving the overlapped wafer T from the lower chuck 231 and transferring the lower wafer W2 to the lower chuck 231. To facilitate the entry of the transfer device 61, the upper chuck 230 and the lower chuck 231 are shifted laterally, and the vertical distance between the upper chuck 230 and the lower chuck 231 is also large.

[0051] On the other hand, the bonding position is a position where the upper wafer W1 and the lower wafer W2 are faced to each other with a predetermined gap therebetween and bonded. The bonding position is, for example, the position shown in Fig. 8. At the bonding position, the gap between the upper wafer W1 and the lower wafer W2 in the vertical direction is narrower than at 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.

[0052] The moving mechanism 290 moves the relative positions of the upper chuck 230 and the lower chuck 231 in the horizontal direction (both the X-axis direction and the Y-axis direction) and 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 may move both. In addition, the moving mechanism 290 may rotate the upper chuck 230 or the lower chuck 231 around the vertical axis.

[0053] 8, upper chuck 230 is partitioned into multiple (e.g., three) regions 230a, 230b, and 230c. These regions 230a, 230b, and 230c are provided in this order from the center toward the periphery of upper chuck 230. Region 230a has a circular shape in a plan view, and regions 230b and 230c have annular shapes in a plan view.

[0054] Suction pipes 240a, 240b, and 240c are provided independently for the respective regions 230a, 230b, and 230c. Different vacuum pumps 241a, 241b, and 241c are connected to the respective suction pipes 240a, 240b, and 240c. The upper chuck 230 can vacuum-suck the upper wafer W1 for each of the regions 230a, 230b, and 230c.

[0055] The upper chuck 230 is provided with a plurality of holding pins 245 that can be raised and lowered in the vertical direction. The plurality of holding pins 245 are connected to a vacuum pump 246, and vacuum-suck the upper wafer W1 by operation of the vacuum pump 246. The upper wafer W1 is vacuum-sucked to the lower ends of the plurality of holding pins 245. Ring-shaped suction pads may be used instead of the plurality of holding pins 245.

[0056] The multiple holding pins 245 move downward to protrude from the holding surface of the upper chuck 230. In this state, the multiple holding pins 245 vacuum-suck the upper wafer W1 and receive it from the transfer device 61. Thereafter, the multiple holding pins 245 move upward to bring the upper wafer W1 into contact with the holding surface of the upper chuck 230. Next, the upper chuck 230 horizontally vacuum-sucks the upper wafer W1 in each of the regions 230a, 230b, and 230c by operation of the vacuum pumps 241a, 241b, and 241c.

[0057] Further, a through hole 243 that passes through the upper chuck 230 in the vertical direction is formed in the center of the upper chuck 230. A pressing part 250, which will be described later, is inserted into the through hole 243. The pressing part 250 presses down the center of the upper wafer W1, which is disposed at a distance from the lower wafer W2, to bring the upper wafer W1 into contact with the lower wafer W2.

[0058] The pushing part 250 has a pushing pin 251 and an outer cylinder 252 which is an elevation guide for the pushing pin 251. The pushing pin 251 is inserted into the through hole 243 by, for example, a driving part (not shown) having a built-in motor, protrudes from the holding surface of the upper chuck 230, and pushes down the center of the upper wafer W1.

[0059] The lower chuck 231 is partitioned into a plurality of (for example, two) regions 231a and 231b. These regions 231a and 231b are provided in this order from the center toward the periphery of the lower chuck 231. The region 231a has a circular shape in a plan view, and the region 231b has an annular shape in a plan view.

[0060] Suction pipes 260a and 260b are provided independently for the respective regions 231a and 231b. Different vacuum pumps 261a and 261b are connected to the respective suction pipes 260a and 260b. The lower chuck 231 can vacuum-suck the lower wafer W2 for each of the regions 231a and 231b.

[0061] A plurality of holding pins 265 that can be raised and lowered in the vertical direction are provided on the lower chuck 231. The lower wafer W2 is placed on the upper ends of the plurality of holding pins 265. The lower wafer W2 may be vacuum-sucked to the upper ends of the plurality of holding pins 265.

[0062] As the multiple holding pins 265 rise, they protrude from the holding surface of the lower chuck 231. In this state, the multiple holding pins 265 receive the lower wafer W2 from the transfer device 61. Thereafter, the multiple holding pins 265 descend, and the lower wafer W2 is brought into contact with the holding surface of the lower chuck 231. Next, the upper chuck 230 horizontally vacuum-sucks the lower wafer W2 in each of the regions 231a and 231b by operation of the vacuum pumps 261a and 261b.

[0063] Next, details of step S109 in Fig. 4 will be described with reference to Fig. 9 to Fig. 11. First, the transfer device 61 loads the upper wafer W1 and the lower wafer W2 into the bonding module 41 (step S111). In step S111, the relative positions of the upper chuck 230 and the lower chuck 231 are the substrate transfer positions shown in Figs. 6 and 7.

[0064] Next, the moving mechanism 290 moves the relative positions of the upper chuck 230 and the lower chuck 231 from the substrate transfer position shown in Fig. 6 and Fig. 7 to the bonding position shown in Fig. 8 (step S112). In step S112, the upper wafer W1 and the lower wafer W2 are aligned. For the alignment, a first camera S1 and a second camera S2 are used as shown in Fig. 10.

[0065] The first camera S1 is fixed to the upper chuck 230 and captures an image of the lower wafer W2 held by the lower chuck 231. A plurality of reference points P21 to P23 are formed in advance on the bonding surface W2j of the lower wafer W2. Patterns of electronic circuits or the like are used as the reference points P21 to P23. The number of reference points can be set arbitrarily.

[0066] On the other hand, the second camera S2 is fixed to the lower chuck 231 and captures an image of the upper wafer W1 held by the upper chuck 230. A plurality of reference points P11 to P13 are formed in advance on the bonding surface W1j of the upper wafer W1. Patterns of electronic circuits or the like are used as the reference points P11 to P13. The number of reference points can be set arbitrarily.

[0067] 10(A), the moving mechanism 290 adjusts the relative horizontal positions of the first camera S1 and the second camera S2. Specifically, the moving mechanism 290 moves the lower chuck 231 in the horizontal direction so that the second camera S2 is positioned substantially directly below the first camera S1. Then, the moving mechanism 290 finely adjusts 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 the horizontal positions of the first camera S1 and the second camera S2 match.

[0068] Next, as shown in Fig. 10(B), the moving mechanism 290 moves the lower chuck 231 vertically upward, and then adjusts the horizontal positions 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 captures images of the reference points P21 to P23 of the lower wafer W2, and the second camera S2 sequentially captures images of the reference points P11 to P13 of the upper wafer W1. Note that Fig. 10(B) shows how the first camera S1 captures the image of the reference point P21 of the lower wafer W2, and the second camera S2 captures the image of the reference point P11 of the upper wafer W1.

[0069] 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 moving 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 with each other when viewed in the vertical direction.

[0070] Next, as shown in Fig. 10(C), the moving mechanism 290 moves the lower chuck 231 vertically upward. As a result, the gap G (see Fig. 8) 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 first displacement gauge S3 and the second displacement gauge S4 are used to adjust the gap G.

[0071] The first displacement meter S3 is fixed to the upper chuck 230, similar to the first camera S1, and measures the thickness of the lower wafer W2 held by the lower chuck 231. The first displacement meter S3, for example, irradiates light onto the lower wafer W2, receives light reflected from both the upper and lower surfaces of the lower wafer W2, and measures the thickness of the lower wafer W2. The thickness is measured, 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 interference method, a triangulation method, or the like. The light source of the first displacement meter S3 is an LED or a laser.

[0072] On the other hand, the second displacement meter S4 is fixed to the lower chuck 231 like the second camera S2, and measures the thickness of the upper wafer W1 held by the upper chuck 230. The second displacement meter S4, for example, irradiates light onto the upper wafer W1, receives light reflected from both the upper and lower surfaces of the upper wafer W1, and measures the thickness of the upper wafer W1. The thickness is measured, for example, when the moving mechanism 290 moves the lower chuck 231 in the horizontal direction. The measurement method of the second displacement meter S4 is, for example, a confocal method, a spectral interference method, a triangulation method, or the like. The light source of the second displacement meter S4 is an LED or a laser.

[0073] The first displacement gauge S3 and the second displacement gauge 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 gauge S3 and the data measured by the second displacement gauge S4, and adjusts the vertical position of the lower chuck 231 so that the gap G becomes a set value.

[0074] Next, the operation of the vacuum pump 241a is stopped, and the vacuum suction of the upper wafer W1 in the region 230a is released, as shown in Fig. 11(A). After that, the pushing pin 251 of the pushing part 250 descends, pushing down the center of the upper wafer W1 and bringing it 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 bonded together.

[0075] Since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified, van der Waals forces (intermolecular forces) are generated between the bonding surfaces W1j and W2j, and the bonding surfaces W1j and W2j are bonded to each other. Furthermore, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been hydrophilized, hydrophilic groups (e.g., OH groups) form hydrogen bonds, and the bonding surfaces W1j and W2j are firmly bonded to each other.

[0076] Next, the operation of the vacuum pump 241b is stopped, and the vacuum suction of the upper wafer W1 in the region 230b is released as shown in Fig. 11(B). Subsequently, the operation of the vacuum pump 241c is stopped, and the vacuum suction of the upper wafer W1 in the region 230c is released as shown in Fig. 11(C).

[0077] In this manner, the vacuum suction of the upper wafer W1 is released stepwise from the center to the periphery, and the upper wafer W1 drops stepwise onto and comes into contact with the lower wafer W2. Then, the bonding of the upper wafer W1 and the lower wafer W2 progresses sequentially from the center to 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 an overlapped wafer T is obtained. After that, the pushing pin 251 is raised to its original position.

[0078] Next, the moving mechanism 290 moves the relative position of the upper chuck 230 and the lower chuck 231 from the joining position shown in Fig. 8 to the substrate transfer position shown in Fig. 6 and Fig. 7 (step S115). For example, the moving mechanism 290 first lowers the lower chuck 231 to widen the vertical distance between the lower chuck 231 and the upper chuck 230. Next, the moving mechanism 290 moves the lower chuck 231 laterally to laterally shift the lower chuck 231 and the upper chuck 230.

[0079] Next, the transfer device 61 carries out the overlapped wafer T to the bonding module 41 (step S116). Specifically, first, the lower chuck 231 releases the hold of the overlapped wafer T. Then, the multiple holding pins 265 rise and deliver the overlapped wafer T to the transfer device 61. After that, the multiple holding pins 265 fall to their original positions.

[0080] Next, the suction surface 300 of the lower chuck 231 will be described with reference to Fig. 12. The technology of the present disclosure is also applicable to the suction surface of the upper chuck 230. In Fig. 12, the hatched area is an area where a suction pressure is generated. The suction surface 300 of the lower chuck 231 includes a plurality of areas that individually generate a suction pressure.

[0081] For example, the suction surface 300 is partitioned by the annular ribs 301, 302, 303, and 304 into a circular first region A, an annular intermediate region B, an annular second region C, and an annular peripheral region D. The first region A, the intermediate region B, the second region C, and the peripheral region D are concentrically arranged in this order from the center of the suction surface 300 toward the periphery.

[0082] Note that the adsorption surface 300 may include the first region A and the second region C, and may not include the intermediate region B and / or the peripheral region D. The intermediate region B is disposed between the first region A and the second region C. The peripheral region D is disposed outside the second region C.

[0083] The intermediate region B is divided into a plurality of arc-shaped regions B1 to B8 by radial ribs 305. Similarly, the second region C is divided into a plurality of arc-shaped regions C1 to C8 by radial ribs 305. The number of regions in the intermediate region B and the number of regions in the second region C are the same in FIG. 12, but may be different.

[0084] The peripheral region D is divided into a plurality of arc-shaped regions D1 to D24 by radial ribs 306. The number of regions in the peripheral region D is greater than the number of regions in the second region C. By dividing the outermost peripheral region D into smaller regions, the order in which suction pressure is generated can be easily adjusted, and the peripheral edge of the warped lower wafer W2 can be sucked in a desired order.

[0085] For example, it is also possible to generate the suction pressure in order from the regions D1 and D13 on the first imaginary line L1 toward the regions D7 and D19 on the second imaginary line L2. The first imaginary line L1 and the second imaginary line L2 intersect at right angles at the center of the suction surface 300 of the lower chuck 231.

[0086] For example, the first virtual straight line L1 includes an area A, areas B1 and B5, areas C1 and C5, and areas D1 and D13. The second virtual straight line L2 includes an area A, areas B3 and B7, areas C3 and C7, and areas D7 and D19.

[0087] A first portion, which is a circumferential portion of the second region C, is disposed on a first virtual straight line L1. The first portion is, for example, the regions C1 and C5. Meanwhile, a second portion, which is another circumferential portion of the second region C, is disposed on a second virtual straight line L2. The second portion is, for example, the regions C3 and C7.

[0088] A third portion, which is a circumferential portion of the peripheral region D, is disposed on a first imaginary straight line L1. The third portion is, for example, the regions D1 and D13. Meanwhile, a fourth portion, which is another circumferential portion of the peripheral region D, is disposed on a second imaginary straight line L2. The fourth portion is, for example, the regions D7 and D19.

[0089] The suction pressure generating unit 310 generates suction pressures individually in the multiple regions constituting the suction surface 300. The suction pressure generating unit 310 may generate suction pressures individually in all of the regions A, B1 to B8, C1 to C8, and D1 to D24 so that the groups described below can be changed as appropriate. However, the suction pressure generating unit 310 does not have to generate suction pressures individually in all of the regions.

[0090] The control device 90 controls the suction pressure generating unit 310, and controls the order in which the suction pressure is generated. The control device 90 generates suction pressure in a plurality of regions A, B1 to B8, C1 to C8, and D1 to D24 for each group described below. Therefore, a plurality of regions belonging to the same group (e.g., regions C1 and C5) may generate suction pressure collectively.

[0091] 13, the suction pressure generating unit 310 includes a plurality of sets of an individual line 311, an on-off valve 312, and a pressure controller 313. When the suction pressure generating unit 310 generates an individual suction pressure in each of the regions A, B1 to B8, C1 to C8, and D1 to D24, the suction pressure generating unit 310 includes an individual line 311 for each of the regions A, B1 to B8, C1 to C8, and D1 to D24. The plurality of individual lines 311 are connected to the mutually different regions A, B1 to B8, C1 to C8, and D1 to D24.

[0092] The individual lines 311 are connected to a suction source such as a vacuum pump. The suction source draws in gas. The suction source may be provided for each individual line 311, or may be provided in common to the individual lines 311.

[0093] The on-off valve 312 opens and closes the gas flow path of the individual line 311 under the control of the control device 90. In addition, the pressure controller 313 controls the air pressure of the gas in the individual line 311 under the control of the control device 90. The pressure controller 313 is, for example, an electro-pneumatic regulator.

[0094] When the suction source is activated and the on-off valve 312 opens the gas flow path, negative pressure is generated at the connected end of the opened flow path, generating adsorption pressure. The magnitude of the adsorption pressure is controlled by the pressure controller 313. On the other hand, when the on-off valve 312 closes the gas flow path and the air pressure at the connected end of the closed flow path returns to atmospheric pressure, the generation of adsorption pressure is released.

[0095] Next, a first example of warping of the lower wafer W2 will be described with reference to Fig. 14. In Fig. 14(A), the gradation of black and white indicates the height of the lower surface (non-bonding surface W2n) of the lower wafer W2 relative to the chucking surface 300 of the lower chuck 231. The closer the color is to black, the lower the height of the lower surface of the lower wafer W2 is, and the smaller the distance between the lower surface of the lower wafer W2 and the chucking surface 300 of the lower chuck 231 is.

[0096] The warpage of the lower wafer W2 is measured, for example, by a warpage measuring device 5 (see FIG. 1). The warpage measuring device 5 is provided separately from the bonding apparatus 1, and transmits measured data to the control device 90. The warpage measuring device 5 may be provided as a part of the bonding apparatus 1. As will be described later, the lower chuck 231 may include a plurality of displacement sensors to measure the warpage of the lower wafer W2.

[0097] 14(A), the lower wafer W2 is warped immediately before the control device 90 generates a chucking pressure on the chucking surface 300 of the lower chuck 231. The warping of the lower wafer W2 occurs, for example, when a plurality of films are stacked on a semiconductor substrate such as a silicon wafer. Each film is formed by a chemical vapor deposition (CVD) method, an atomic layer deposition (ALD) method, a spin-on method, or the like. During film formation, a difference in thermal expansion generates stress, causing the lower wafer W2 to warp.

[0098] The lower surface of the lower wafer W2 often has a warp that is symmetrical with respect to a first imaginary straight line L1 and a second imaginary straight line L2 (see FIG. 12) that intersect at right angles at the center of the chucking surface 300 of the lower chuck 231, that is, an axisymmetric warp. This is because the Young's modulus, Poisson's ratio, and shear modulus of elasticity of a semiconductor substrate such as a silicon wafer change in a 90° cycle. The first imaginary straight line L1 and the second imaginary straight line L2 extend in a specific crystal orientation of the semiconductor substrate when viewed from a direction (Z-axis direction) perpendicular to the chucking surface 300.

[0099] The warpage of the lower wafer W2 is represented by the distance between the lower chuck 231 and the lower wafer W2 on the first imaginary straight line L1 and the second imaginary straight line L2. For example, as shown in Fig. 14(B), the closer to the center of the suction surface 300, the larger the distance between the suction surface 300 and the lower wafer W2 on the first imaginary straight line L1. Also, as shown in Fig. 14(C), the farther from the center of the suction surface 300, the larger the distance between the suction surface 300 and the lower wafer W2 on the second imaginary straight line L2.

[0100] Therefore, the distance between the second portions C3, C7 of the second region C and the lower wafer W2 is larger than the distance between the first portions C1, C5 of the second region C and the lower wafer W2. Also, the distance between the fourth portions D7, D19 of the peripheral region D and the lower wafer W2 is larger than the distance between the third portions D1, D13 of the peripheral region D and the lower wafer W2.

[0101] Next, with reference to FIG. 15 and Table 1, a first example of the order in which the suction pressure is generated when the lower wafer W2 shown in FIG.

[0102] [Table 1]

[0103] The control device 90 generates suction pressure by dividing the multiple regions A, B1 to B8, C1 to C8, and D1 to D24 into groups G1 to G6 shown in Table 1, for example. The order in which suction pressure is generated is G1, G2, G3, G4, G5, and G6. G1 is generated first, and G6 is generated last. The control device 90 does not release the suction pressure once it has been generated until suction pressure has been generated in all of the groups G1 to G6.

[0104] The order in which suction pressure is generated on the first virtual straight line L1 is group G1 (area A), group G2 (areas B1, B5), group G3 (areas C1, C5), and group G4 (areas D1, D13). On the first virtual straight line L1, suction pressure is generated in order from the center to the periphery of the suction surface 300. Unlike the case in which the order is reversed, wrinkles can be released to the outside, and the occurrence of wrinkles can be suppressed.

[0105] The order in which the suction pressure is generated on the second virtual straight line L2 is group G1 (area A), group G2 (areas B3, B7), group G5 (areas C3, C7), and group G6 (areas D7, D19). On the second virtual straight line L2, the suction pressure is generated in order from the center to the periphery of the suction surface 300. Unlike the case in which the order is reversed, wrinkles can be released to the outside, and the occurrence of wrinkles can be suppressed.

[0106] The control device 90 of this embodiment generates suction pressure in the first region A, generates suction pressure in the first parts C1 and C5 of the second region C, and generates suction pressure in the second parts C3 and C7 of the second region C, in this order. First, the control device 90 generates suction pressure in the first region A. It is possible to generate suction pressure at the center of the suction surface 300 on both the first virtual straight line L1 and the second virtual straight line L2.

[0107] Thereafter, the control device 90 generates a suction pressure in the first portions C1 and C5 of the second region C. As shown in FIG. 14, the first portions C1 and C5 have a smaller gap with the lower wafer W2 than the second portions C3 and C7, and the degree of vacuum is likely to be high. Therefore, the lower wafer W2 can be attracted to the first portions C1 and C5. The lower wafer W2 comes into contact with the first portions C1 and C5, and the warpage of the lower wafer W2 is reduced.

[0108] As a result, the distance between the second parts C3, C7 and the lower wafer W2 also becomes smaller. Thereafter, when the control device 90 generates a suction pressure in the second parts C3, C7, the degree of vacuum is easily increased, and the lower wafer W2 can be attracted to the second parts C3, C7. The lower wafer W2 comes into contact with the second parts C3, C7.

[0109] As described above, by shifting the timing at which the suction pressure is generated between the first parts C1 and C5 and the second parts C3 and C7, the degree of vacuum can be efficiently increased and the lower wafer W2 can be efficiently suctioned.

[0110] The control device 90 of this embodiment generates suction pressure in the entire intermediate region B after the first region A and before the first portions C1 and C5 of the second region C. The lower wafer W2 can be pulled to the intermediate region B. The lower wafer W2 comes into contact with the entire intermediate region B, reducing the warpage of the lower wafer W2. As a result, the gap between the first portions C1 and C5 and the lower wafer W2 also becomes smaller. Therefore, it is easy to increase the degree of vacuum when suction pressure is generated in the first portions C1 and C5. By generating suction pressure in the above order, wrinkles can also be released.

[0111] The control device 90 of this embodiment generates adsorption pressure in the first region A, generates adsorption pressure in the first parts C1 and C5 of the second region C, generates adsorption pressure in the third parts D1 and D13 of the peripheral region D, generates adsorption pressure in the second parts C3 and C7 of the second region C, and generates adsorption pressure in the fourth parts D7 and D19 of the peripheral region D, in this order.

[0112] As shown in FIG. 14, the third parts D1 and D13 have a smaller gap between them and the lower wafer W2 than the second parts C3 and C7, and the degree of vacuum is likely to be high. Therefore, by generating suction pressure in the third parts D1 and D13 before the second parts C3 and C7, the lower wafer W2 can be attracted to the third parts D1 and D13. The lower wafer W2 comes into contact with the third parts D1 and D13, and the warpage of the lower wafer W2 is reduced. As a result, the gap between the second parts C3 and C7 and the lower wafer W2 is also reduced. Therefore, when suction pressure is generated in the second parts C3 and C7, the degree of vacuum is likely to be increased.

[0113] As shown in FIG. 14, the second parts C3 and C7 have a smaller gap with the lower wafer W2 than the fourth parts D7 and D19, and the degree of vacuum is easily increased. Therefore, by generating a suction pressure in the second parts C3 and C7 before the fourth parts D7 and D19, the lower wafer W2 can be attracted to the second parts C3 and C7. The lower wafer W2 comes into contact with the second parts C3 and C7, and the warpage of the lower wafer W2 is reduced. As a result, the gap between the fourth parts D7 and D19 and the lower wafer W2 is also reduced. Therefore, when a suction pressure is generated in the fourth parts D7 and D19, the degree of vacuum is easily increased. The lower wafer W2 can also be attracted to the fourth parts D7 and D19, and the entire lower surface of the lower wafer W2 can be suctioned.

[0114] As shown in Table 1, the control device 90 may temporarily stop the generation of suction pressure, for example, in groups G7 to G8, after generating the suction pressure over the entire suction surface 300. Next, the control device 90 generates suction pressure again in groups G7 and G8. The order of regeneration is G7, G8, with G7 being first and G8 being last. As a result, the control device 90 generates suction pressure over the entire suction surface 300 again.

[0115] The control device 90 of this embodiment generates the suction pressure over the entire suction surface 300, and then temporarily stops the generation of the suction pressure in at least a part of the second region C while generating the suction pressure over the entire peripheral region D, and then generates the suction pressure again. With the entire peripheral region of the lower wafer W2 being suctioned, wrinkles generated in region E1 shown in Fig. 15(A) can be dispersed to region E2 shown in Fig. 15(B).

[0116] The control device 90 of this embodiment temporarily stops the generation of suction pressure in part of the intermediate region B in addition to part of the second region C, and then generates suction pressure again. By expanding the area where the generation of suction pressure is stopped, wrinkles can be widely dispersed. The control device 90 then generates suction pressure again in part of the intermediate region B and part of the second region C, in that order. Wrinkles can be released to the outside.

[0117] Next, with reference to FIG. 16 and Table 2, a second example of the order in which the suction pressure is generated when the lower wafer W2 shown in FIG. 14 is suctioned will be described.

[0118] [Table 2]

[0119] The control device 90 generates suction pressure by dividing the multiple regions A, B1 to B8, C1 to C8, and D1 to D24 into groups G1 to G6 shown in Table 2. The order in which the suction pressure is generated is G1, G2, G3, G4, G5, and G6. The method of dividing and the order of the groups G1 to G6 are the same as in the first example, so a description thereof will be omitted.

[0120] Next, after generating the suction pressure over the entire suction surface 300, the control device 90 temporarily stops the generation of the suction pressure in the groups G7 to G9 shown in Table 2. Next, the control device 90 generates the suction pressure again in the groups G7 to G9. The order of regeneration is G7, G8, and G9. G7 is first and G9 is last. As a result, the control device 90 generates the suction pressure over the entire suction surface 300 again.

[0121] For example, the control device 90 generates suction pressure over the entire suction surface 300, and then temporarily releases suction pressure in the third portions D1 and D13 of the peripheral region D while generating suction pressure in the fourth portions D7 and D19 of the peripheral region D, and then generates suction pressure again. Since suction is released from a portion of the peripheral region of the lower wafer W2, wrinkles can be released. The portion of the peripheral region of the lower wafer W that maintains suction is the portion that had the greatest warpage. Compared to releasing suction from the portion that had the greatest warpage, this can prevent poor suction during re-suction.

[0122] Furthermore, the control device 90 may temporarily cancel the generation of suction pressure in the first parts C1 and C5 of the second area C, in addition to the third parts D1 and D13 of the peripheral area D. By expanding the area where the generation of suction pressure is canceled, wrinkles can be widely dispersed. Thereafter, the control device 90 generates suction pressure again in the first parts C1 and C5 and the third parts D1 and D13 in that order. This allows the wrinkles to escape.

[0123] Furthermore, the control device 90 may temporarily cancel the generation of suction pressure in part of the intermediate region B, in addition to the first portions C1 and C5 of the second region C. By expanding the area where the generation of suction pressure is canceled, wrinkles can be widely dispersed. Thereafter, the control device 90 generates suction pressure again in part of the intermediate region B, the first portions C1 and C5 of the second region C, and the third portions D1 and D13 of the peripheral region D, in that order. This allows the wrinkles to escape.

[0124] Next, a second example of warping of the lower wafer W2 will be described with reference to Fig. 17. In Fig. 17(A), the gradation of black and white indicates the height of the lower surface (non-bonding surface W2n) of the lower wafer W2 relative to the chucking surface 300 of the lower chuck 231. The closer the color is to black, the lower the height of the lower surface of the lower wafer W2 is, and the narrower the distance between the lower surface of the lower wafer W2 and the chucking surface 300 of the lower chuck 231 is.

[0125] The warpage of the lower wafer W2 is often symmetrical with respect to a first imaginary line L1 and a second imaginary line L2 (see FIG. 12) that are perpendicular to each other at the center of the chucking surface 300 of the lower chuck 231, that is, has line-symmetrical warpage. The warpage of the lower wafer W2 is represented by the distance between the lower chuck 231 and the lower wafer W2 on the first imaginary line L1 and the second imaginary line L2.

[0126] For example, as shown in Fig. 17(B), the suction surface 300 and the lower wafer W2 are in contact with each other along the entire first imaginary straight line L1. Also, as shown in Fig. 17(C), in the second imaginary straight line L2, the distance between the suction surface 300 and the lower wafer W2 increases as the distance increases from the center of the suction surface 300.

[0127] Therefore, the distance between the second portions C3, C7 of the second region C and the lower wafer W2 is larger than the distance between the first portions C1, C5 of the second region C and the lower wafer W2. Also, the distance between the fourth portions D7, D19 of the peripheral region D and the lower wafer W2 is larger than the distance between the third portions D1, D13 of the peripheral region D and the lower wafer W2.

[0128] Next, with reference to FIG. 18 and Table 3, an example of the order in which the suction pressure is generated when the lower wafer W2 shown in FIG.

[0129] [Table 3]

[0130] The control device 90 generates suction pressure by dividing the multiple regions A, B1 to B8, C1 to C8, and D1 to D24 into groups G1 to G4 shown in Table 3, for example. The order in which suction pressure is generated is G1, G2, G3, and G4. G1 is generated first, and G4 is generated last. The control device 90 does not release the suction pressure once it has been generated until suction pressure has been generated in all of the groups G1 to G4.

[0131] The order in which suction pressure is generated on the first imaginary straight line L1 is group G1 (area A), followed by group G2 (areas B1, B5, C1, C5, D1, D13). On the first imaginary straight line L1, suction pressure is generated in order from the center to the periphery of the suction surface 300. Unlike the case in which the order is reversed, wrinkles can be released to the outside, and the occurrence of wrinkles can be suppressed.

[0132] The order in which the suction pressure is generated on the second virtual straight line L2 is group G1 (area A), group G2 (areas B3, B7), group G3 (areas C3, C7), and group G4 (areas D7, D19). On the second virtual straight line L2, the suction pressure is generated in order from the center to the periphery of the suction surface 300. Unlike the case in which the order is reversed, wrinkles can be released to the outside, and the occurrence of wrinkles can be suppressed.

[0133] The control device 90 generates a suction pressure in the first region A, generates a suction pressure in the first parts C1 and C5 of the second region C, and generates a suction pressure in the second parts C3 and C7 of the second region C, in that order. Therefore, the degree of vacuum can be efficiently increased, and the lower wafer W2 can be efficiently suctioned.

[0134] In order to shorten the processing time, the control device 90 generates a suction pressure in the entire intermediate region B simultaneously with the first portions C1 and C5 of the second region C. The warpage shown in Fig. 17 is smaller than the warpage shown in Fig. 14. Therefore, the lower wafer W2 can be attracted to the entire intermediate region B simultaneously with the first portions C1 and C5 of the second region C.

[0135] Furthermore, in order to shorten the processing time, the control device 90 generates suction pressure simultaneously in the first portions C1 and C5 of the second region C and the third portions D1 and D13 of the peripheral region D. As shown in Fig. 17(B), the third portions D1 and D13 are in contact with the lower wafer W2 like the first portions C1 and C5, and therefore can generate suction pressure simultaneously.

[0136] Furthermore, in order to shorten the processing time, the control device 90 simultaneously generates suction pressure in the second portions C3 and C7 of the second region C and the fifth portions D10 and D22 of the peripheral region D. The fifth portions D10 and D22 of the peripheral region D are disposed between the third portions D1 and D13 and the fourth portions D7 and D19 of the peripheral region D. The control device 90 generates suction pressure in the fifth portions D10 and D22 before the fourth portions D7 and D19.

[0137] The fifth parts D10 and D22 have a smaller distance from the lower wafer W2 than the fourth parts D7 and D19, and the degree of vacuum is likely to be high. Therefore, by generating a suction pressure in the fifth parts D10 and D22 before the fourth parts D7 and D19, the lower wafer W2 can be attracted to the fifth parts D10 and D22.

[0138] As a result, the distance between the fourth parts D7, D19 and the lower wafer W2 also becomes smaller. Thereafter, when the control device 90 generates a suction pressure in the fourth parts D7, D19, the degree of vacuum is easily increased, and the lower wafer W2 can be attracted to the fourth parts D7, D19. The entire lower surface of the lower wafer W2 can be suctioned.

[0139] As described above, the control device 90 generates adsorption pressure in the first region A, simultaneously generates adsorption pressure in the first parts C1, C5 of the second region C and the third parts D1, D13 of the peripheral region D, simultaneously generates adsorption pressure in the second parts C3, C7 of the second region C and the fifth parts D10, D22 of the peripheral region D, and generates adsorption pressure in the fourth parts D7, D19 of the peripheral region D, in this order.

[0140] Then, after generating the suction pressure on the entire suction surface 300, the control device 90 temporarily stops the generation of the suction pressure on the third parts D1, D13 and the fifth parts D10, D22 of the peripheral region D while generating the suction pressure on the fourth parts D7, D19 of the peripheral region D, and then generates the suction pressure again. Since the suction of a part of the peripheral region of the lower wafer W2 is released, wrinkles can be released. The part of the peripheral region of the lower wafer W that maintains suction is the part that was most warped. Compared to releasing the suction of the part that was most warped, this prevents the occurrence of suction failures when re-sucking.

[0141] The control device 90 may temporarily cancel the generation of suction pressure in part of the second region C, in addition to the third portions D1, D13 and fifth portions D10, D22 of the peripheral region D. By expanding the area where the generation of suction pressure is canceled, wrinkles can be widely dispersed. After that, suction pressure is again generated in part of the second region C and in the third portions D1, D13 and fifth portions D10, D22 of the peripheral region D, in that order. Wrinkles can be released to the outside.

[0142] Next, the displacement sensor 320 will be described with reference to FIG. 19(A). The displacement sensor 320 measures the distance between the chucking surface 300 and the substrate W. The displacement sensor 320 is, for example, a laser displacement meter. The displacement sensor 320 is of a non-contact type, but may be of a contact type. The lower chuck 231 includes a plurality of displacement sensors 320. The plurality of displacement sensors 320 can measure the warpage of the lower wafer W2. In addition, the contact between the lower wafer W and the chucking surface 300 can be confirmed.

[0143] 19(A) to 19(C), the local suction unit 330 will be described. The lower chuck 231 includes ribs (e.g., ribs 302, 303) that define the chucking surface 300, and includes the local suction unit 330 that locally sucks the lower wafer W2 in a part of the area surrounded by the ribs (e.g., area C3). A high degree of vacuum can be generated locally, and the lower wafer W2 can be attracted to the area C3.

[0144] The local suction unit 330 is preferably disposed at least in the second parts C3 and C7 of the second region C. This is because the distance between the lower wafer W2 and the suction surface 300 is largest in the second parts C3 and C7 in the second region C. The local suction unit 330 may be disposed in all of the regions C1 to C8 of the second region C.

[0145] The local suction unit 330 is preferably disposed at least in the fourth portions D7 and D19 of the peripheral region D. This is because the distance between the lower wafer W2 and the suction surface 300 is largest in the fourth portions D7 and D19 in the peripheral region D. The local suction unit 330 may be disposed in all of the regions D1 to D24 of the peripheral region D.

[0146] The local suction unit 330 may be disposed in the intermediate region B. The local suction unit 330 does not have to be disposed in the first region A.

[0147] 19(A), the local suction unit 330 is, for example, a vacuum suction pad, and is disposed at the same height as the ribs 302, 303. The vacuum suction pad may be expandable and contractible, and may protrude beyond the ribs 302, 303, as shown in Fig. 19(B). The lower wafer W2 can be reliably attracted to the region C3.

[0148] 19C, the local suction unit 330 may be a suction pad that suctions the lower wafer W2 by the Bernoulli effect. Unlike a vacuum suction pad, a Bernoulli type suction pad can suction the lower wafer W2 in a non-contact manner.

[0149] Although the embodiments of the substrate processing apparatus and the substrate processing method according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present disclosure. [Explanation of symbols]

[0150] 1 Bonding equipment (substrate processing equipment) 90 Control device (control unit) 231 Lower chuck (holding part) 300 Adsorption surface 310 Adsorption pressure generating unit A 1st area C 2nd area C1, C5 Part 1 C3, C7 Part 2 W2 Lower wafer (substrate)

Claims

1. a holder including, on an adsorption surface for adsorbing the substrate, a circular first region and an annular second region disposed outside the first region; an adsorption pressure generating unit that generates an adsorption pressure individually in the first region, in a first portion that is a circumferential portion of the second region, and in a second portion that is another circumferential portion of the second region; A control unit that controls the suction pressure generating unit, immediately before the control unit generates a suction pressure on the suction surface, the substrate is warped, and a distance between the second portion of the second region and the substrate is larger than a distance between the first portion of the second region and the substrate; the suction surface includes a first virtual line passing through a center of the suction surface and a second virtual line perpendicular to the first virtual line at the center, immediately before the control unit generates a suction pressure on the suction surface, the closer to the center the first virtual line is, the larger the distance between the suction surface and the substrate becomes, and the farther from the center the second virtual line is, the larger the distance between the suction surface and the substrate becomes, the first portion of the second region is disposed on the first virtual line, and the second portion of the second region is disposed on the second virtual line; The adsorption surface further includes an annular peripheral region outside the second region, the suction pressure generating section generates a suction pressure individually in a third section which is a circumferential part of the peripheral region and in a fourth section which is another circumferential part of the peripheral region; the third portion of the peripheral region is disposed on the first imaginary straight line, and the fourth portion of the peripheral region is disposed on the second imaginary straight line; the control unit causes the controller to execute, in this order, a suction pressure in the first region, a suction pressure in the first portion of the second region, a suction pressure in the third portion of the peripheral region, a suction pressure in the second portion of the second region, and a suction pressure in the fourth portion of the peripheral region; the control unit generates an adsorption pressure on the entire suction surface, and then temporarily cancels the generation of the adsorption pressure in the third part of the peripheral region while generating an adsorption pressure in the fourth part of the peripheral region, and then generates an adsorption pressure again.

2. The adsorption surface further includes an annular intermediate region between the first region and the second region, The suction pressure generating unit generates a suction pressure in the intermediate region, The substrate processing apparatus of claim 1 , wherein the control unit generates a suction pressure in the entire intermediate region after the first region and before the first portion of the second region.

3. 3. The substrate processing apparatus of claim 1, wherein the control unit generates an adsorption pressure on the entire adsorption surface, and then temporarily cancels the generation of the adsorption pressure on the third part of the peripheral region and the first part of the second region while generating an adsorption pressure on the fourth part of the peripheral region, and then generates an adsorption pressure again on the first part of the second region and the third part of the peripheral region in this order.

4. a holder including, on an adsorption surface for adsorbing the substrate, a circular first region and an annular second region disposed outside the first region; an adsorption pressure generating unit that generates an adsorption pressure individually in the first region, in a first portion that is a circumferential portion of the second region, and in a second portion that is another circumferential portion of the second region; A control unit that controls the suction pressure generating unit, immediately before the control unit generates a suction pressure on the suction surface, the substrate is warped, and a distance between the second portion of the second region and the substrate is larger than a distance between the first portion of the second region and the substrate; the suction surface includes a first virtual line passing through a center of the suction surface and a second virtual line perpendicular to the first virtual line at the center, immediately before the control unit generates a suction pressure on the suction surface, the closer to the center the first virtual line is, the larger the distance between the suction surface and the substrate becomes, and the farther from the center the second virtual line is, the larger the distance between the suction surface and the substrate becomes, the first portion of the second region is disposed on the first virtual line, and the second portion of the second region is disposed on the second virtual line; The adsorption surface further includes an annular peripheral region outside the second region, the suction pressure generating section generates a suction pressure individually in a third section which is a circumferential part of the peripheral region and in a fourth section which is another circumferential part of the peripheral region; the third portion of the peripheral region is disposed on the first imaginary straight line, and the fourth portion of the peripheral region is disposed on the second imaginary straight line; the control unit causes the controller to execute, in this order, a suction pressure in the first region, a suction pressure in the first portion of the second region, a suction pressure in the third portion of the peripheral region, a suction pressure in the second portion of the second region, and a suction pressure in the fourth portion of the peripheral region; the control unit, after generating an adsorption pressure over the entire suction surface, temporarily releases the generation of the adsorption pressure in at least a portion of the second region while generating an adsorption pressure over the entire peripheral region, and then generates the adsorption pressure again.

5. a holder including, on an adsorption surface for adsorbing the substrate, a circular first region and an annular second region disposed outside the first region; an adsorption pressure generating unit that generates an adsorption pressure individually in the first region, in a first portion that is a circumferential portion of the second region, and in a second portion that is another circumferential portion of the second region; A control unit that controls the suction pressure generating unit, immediately before the control unit generates a suction pressure on the suction surface, the substrate is warped, and a distance between the second portion of the second region and the substrate is larger than a distance between the first portion of the second region and the substrate; the suction surface includes a first virtual line passing through a center of the suction surface and a second virtual line perpendicular to the first virtual line at the center, immediately before the control unit generates a suction pressure on the suction surface, the suction surface and the substrate are in contact with each other along the entire first imaginary line, and on the second imaginary line, the distance between the suction surface and the substrate increases as the suction surface moves away from the center; the first portion of the second region is disposed on the first virtual line, and the second portion of the second region is disposed on the second virtual line; The control unit of the substrate processing apparatus performs the following operations in this order: generating an adsorption pressure in the first region, generating an adsorption pressure in the first portion of the second region, and generating an adsorption pressure in the second portion of the second region.

6. The adsorption surface further includes an annular intermediate region between the first region and the second region, The suction pressure generating unit generates a suction pressure in the intermediate region, The substrate processing apparatus of claim 5 , wherein the control unit generates a suction pressure on the first portion of the second region and simultaneously on the entire intermediate region.

7. The adsorption surface further includes an annular peripheral region outside the second region, the suction pressure generating section generates suction pressures individually in a third section which is a circumferential portion of the peripheral region, a fourth section which is another circumferential portion of the peripheral region, and a fifth section which is yet another circumferential portion of the peripheral region; the third portion of the peripheral region is disposed on the first imaginary straight line, and the fourth portion of the peripheral region is disposed on the second imaginary straight line; 7. The substrate processing apparatus of claim 5, wherein the control unit controls the control unit to execute, in this order, generating an adsorption pressure in the first region, simultaneously generating an adsorption pressure in the first portion of the second region and the third portion of the peripheral region, simultaneously generating an adsorption pressure in the second portion of the second region and the fifth portion of the peripheral region, and generating an adsorption pressure in the fourth portion of the peripheral region.

8. 8. The substrate processing apparatus according to claim 7, wherein the control unit generates an adsorption pressure on the entire suction surface, and then temporarily cancels generation of the adsorption pressure in the third and fifth parts of the peripheral region while generating an adsorption pressure in the fourth part of the peripheral region, and then generates an adsorption pressure again.

9. 9. The substrate processing apparatus of claim 8, wherein the control unit generates an adsorption pressure on the entire adsorption surface, and then temporarily cancels the generation of the adsorption pressure on the third and fifth portions of the peripheral region and a part of the second region while generating an adsorption pressure on the fourth portion of the peripheral region, and then generates an adsorption pressure again on the part of the second region, and the third and fifth portions of the peripheral region in this order.

10. 10. The substrate processing apparatus according to claim 1, wherein the holding unit includes a plurality of displacement sensors that measure a distance between the suction surface and the substrate.

11. The substrate processing apparatus according to any one of claims 1 to 10, wherein the holding portion includes a rib that partitions the suction surface, and includes a local suction portion that locally sucks the substrate in a portion of the area surrounded by the rib.

12. a second holding part that adsorbs a second substrate at a distance from the substrate held by the holding part; a pressing portion that presses down a center of the second substrate held by the second holding portion to bring the center of the substrate into contact with the center of the second substrate, The substrate processing apparatus of any one of claims 1 to 11, wherein the control unit causes the pushing portion to contact the center of the second substrate with the center of the substrate, then releases the suction of the second substrate by the second holding portion, and brings the bonding surface of the second substrate into contact with the bonding surface of the substrate over the entire surface, thereby bonding them.

13. A substrate processing method comprising: processing the substrate using a substrate processing apparatus as described in any one of claims 1 to 12 while the substrate is adsorbed onto the adsorption surface of the holding part.

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