JP2018190826A - Joint device and joint method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce local distortion occurring in an outer periphery part of a substrate after joining.SOLUTION: A joint device according to an embodiment includes a first holding part, a second holding part, a striker, and a deformation part. The first holding part suctions a first substrate to hold the first substrate from above. The second holding part suctions a second substrate to hold the second substrate from below. The striker presses a center part of the first substrate from above to cause the center part to contact with the second substrate. The deformation part deforms at least a part of an outer periphery part of the second substrate suctioned and held by the second holding part along an in-plane direction of the second substrate.SELECTED DRAWING: Figure 10E

Description

  Embodiments disclosed herein relate to a joining apparatus and a joining method.

  Conventionally, as a method for bonding substrates such as semiconductor wafers, a method for semipermanently bonding two substrates using intermolecular force is known.

  In this method, two substrates are arranged opposite to each other in the vertical direction, and then the central portion of the upper substrate (upper substrate) is pushed down to contact the central portion of the lower substrate (lower substrate). Thereby, first, the central portions of the upper substrate and the lower substrate are bonded to each other by intermolecular force to form a bonded region, and then the bonded region is expanded toward the outer peripheral portion of the substrate. And the lower substrate are bonded all over.

  Here, since the upper substrate is bonded to the lower substrate in a warped state, extra stress is applied to the upper substrate, and the stress may cause distortion in the bonded substrate.

  In order to solve this problem, for example, it has been proposed to hold the lower substrate in a warped state by making the holding surface of the holding portion holding the lower substrate convex (see Patent Document 1). ). According to this technique, the distortion which arises in the board | substrate after joining can be reduced by warping a lower board | substrate similarly to an upper board | substrate.

JP 2016-39254 A

  However, even if measures are taken as in the prior art, local distortion may occur in the substrate after bonding.

  An object of one embodiment is to provide a bonding apparatus and a bonding method capable of reducing local distortion generated in the outer peripheral portion of a substrate after bonding.

  The joining apparatus which concerns on 1 aspect of embodiment is provided with a 1st holding | maintenance part, a 2nd holding | maintenance part, a striker, and a deformation | transformation part. The first holding unit sucks and holds the first substrate from above. The second holding unit sucks and holds the second substrate from below. The striker presses the central portion of the first substrate from above to contact the second substrate. The deforming portion deforms at least a part of the outer peripheral portion of the second substrate held by suction by the second holding portion along the in-plane direction of the second substrate.

  According to one aspect of the embodiment, it is possible to reduce local distortion generated in the outer peripheral portion of the substrate after bonding.

FIG. 1 is a schematic plan view illustrating a configuration of a bonding system according to an embodiment. FIG. 2 is a schematic side view illustrating the configuration of the joining system according to the embodiment. FIG. 3 is a schematic side view of the first substrate and the second substrate. FIG. 4 is a schematic plan view showing the configuration of the bonding apparatus. FIG. 5 is a schematic side view showing the configuration of the bonding apparatus. FIG. 6 is a schematic side cross-sectional view showing the configuration of the upper chuck and the lower chuck. FIG. 7 is a schematic plan view showing the configuration of the deformation portion. FIG. 8A is a schematic enlarged view of a portion H shown in FIG. FIG. 8B is a schematic enlarged view of an H portion shown in FIG. FIG. 9 is a flowchart showing a part of the processing executed by the joining system. FIG. 10A is an operation explanatory diagram of the joining process. FIG. 10B is an operation explanatory diagram of the bonding process. FIG. 10C is an operation explanatory diagram of the joining process. FIG. 10D is an operation explanatory diagram of the bonding process. FIG. 10E is an operation explanatory diagram of the bonding process. FIG. 10F is an explanatory diagram of the operation of the bonding process. FIG. 10G is an explanatory diagram of the operation of the bonding process. FIG. 11 is a schematic plan view showing the configuration of the deforming portion according to the first modification. FIG. 12A is a schematic side view illustrating a configuration of a deforming unit according to a second modification. FIG. 12B is a schematic side view illustrating the configuration of the deforming unit according to the second modification. FIG. 12C is a schematic side view illustrating the configuration of the deforming unit according to the second modification. FIG. 13A is a schematic side view illustrating a configuration of a deforming unit according to a third modification. FIG. 13B is a schematic side view illustrating a configuration of a deforming unit according to a third modification. FIG. 14 is a schematic side view illustrating a configuration of a deforming unit according to a fourth modification. FIG. 15 is a schematic side view showing the configuration of the deforming portion according to the fifth modification.

  Hereinafter, embodiments of a joining apparatus and a joining method disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

<1. Structure of joining system>
First, the configuration of the joining system according to the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic plan view showing a configuration of a joining system according to an embodiment, and FIG. 2 is a schematic side view thereof. FIG. 3 is a schematic side view of the first substrate and the second substrate. In the following, in order to clarify the positional relationship, the X-axis direction, the Y-axis direction, and the Z-axis direction that are orthogonal to each other are defined, and the positive direction of the Z-axis is the vertically upward direction. Moreover, in each drawing including FIGS. 1 to 3, only components necessary for the description are shown, and description of general components may be omitted.

  The bonding system 1 according to the embodiment shown in FIG. 1 forms a superposed substrate T by bonding a first substrate W1 and a second substrate W2 (see FIG. 3).

  The first substrate W1 is a substrate in which a plurality of electronic circuits are formed on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. The second substrate W2 is, for example, a bare wafer on which no electronic circuit is formed. The first substrate W1 and the second substrate W2 have substantially the same diameter.

  An electronic circuit may be formed not only on the first substrate W1 but also on the second substrate W2. Further, as the above-described compound semiconductor wafer, for example, a wafer containing gallium arsenide, silicon carbide, gallium nitride, indium phosphide, or the like can be used.

  Hereinafter, the first substrate W1 may be referred to as “upper wafer W1”, the second substrate W2 may be referred to as “lower wafer W2”, and the superposed substrate T may be referred to as “superimposed wafer T”.

  In the following, as shown in FIG. 3, the plate surface of the upper wafer W1 on the side bonded to the lower wafer W2 is referred to as “bonded surface W1j”, and is opposite to the bonded surface W1j. The plate surface is described as “non-bonding surface W1n”. Of the plate surfaces of the lower wafer W2, the plate surface on the side bonded to the upper wafer W1 is described as “bonded surface W2j”, and the plate surface opposite to the bonded surface W2j is referred to as “non-bonded surface W2n”. Describe.

  As shown in FIG. 1, the joining system 1 includes a carry-in / out station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are arranged in the order of the loading / unloading station 2 and the processing station 3 along the positive direction of the X axis. Further, the carry-in / out station 2 and the processing station 3 are integrally connected.

  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. On each mounting plate 11, cassettes C1, C2, and C3 for storing a plurality of (for example, 25) substrates in a horizontal state are mounted. For example, the cassette C1 is a cassette that accommodates the upper wafer W1, the cassette C2 is a cassette that accommodates the lower wafer W2, and the cassette C3 is a cassette that accommodates the superposed wafer T.

  The conveyance area 20 is arranged adjacent to the X-axis positive direction side of the mounting table 10. In the transport region 20, a transport path 21 extending in the Y-axis direction and a transport device 22 movable along the transport path 21 are provided. The transport device 22 is movable not only in the Y-axis direction but also in the X-axis direction and can be swung around the Z-axis, and cassettes C1 to C3 placed on the placement plate 11 and a processing station 3 described later. The upper wafer W1, the lower wafer W2, and the overlapped wafer T are transferred to and from the third processing block G3.

  Note that the number of cassettes C1 to C3 mounted on the mounting plate 11 is not limited to the illustrated one. In addition to the cassettes C1, C2, and C3, the placement plate 11 may be loaded with a cassette or the like for collecting a substrate having a problem.

  The processing station 3 is provided with a plurality of processing blocks including various devices, for example, three processing blocks G1, G2, and G3. For example, the first processing block G1 is provided on the front side of the processing station 3 (Y-axis negative direction side in FIG. 1), and the second side is disposed on the back side of the processing station 3 (Y-axis positive direction side in FIG. 1). A processing block G2 is provided. A third processing block G3 is provided on the loading / unloading station 2 side of the processing station 3 (X-axis negative direction side in FIG. 1).

  In the first processing block G1, a surface modification device 30 for modifying the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 is disposed. The surface modification device 30 cuts the SiO2 bond at the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 to form single-bonded SiO, so that the bonding surfaces W1j, W2j is modified.

  In the surface reformer 30, for example, oxygen gas or nitrogen gas, which is a processing gas, is excited to be turned into plasma and ionized in a reduced pressure atmosphere. The oxygen ions or nitrogen ions are irradiated onto the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2, whereby the bonding surfaces W1j and W2j are plasma-treated and modified.

  In the second processing block G2, a surface hydrophilizing device 40 and a joining device 41 are arranged. The surface hydrophilizing device 40 hydrophilizes the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 with pure water, for example, and cleans the bonding surfaces W1j and W2j. In the surface hydrophilizing device 40, for example, pure water is supplied onto the upper wafer W1 or the lower wafer W2 while rotating the upper wafer W1 or the lower wafer W2 held by the spin chuck. Thereby, the pure water supplied onto the upper wafer W1 or the lower wafer W2 diffuses on the bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2, and the bonding surfaces W1j and W2j are hydrophilized.

  The bonding apparatus 41 bonds the hydrophilicized upper wafer W1 and lower wafer W2 by intermolecular force. The configuration of the joining device 41 will be described later.

  In the third processing block G3, as shown in FIG. 2, transition (TRS) devices 50 and 51 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T are provided in two stages in order from the bottom. The number of transition devices 50 and 51 is not limited to two.

  Further, as shown in FIG. 1, a transport area 60 is formed in an area surrounded by the first processing block G1, the second processing block G2, and the third processing block G3. A transport device 61 is disposed in the transport area 60. The transport device 61 includes a transport arm that can move around the vertical direction, the horizontal direction, and the vertical axis, for example. The transfer device 61 moves in the transfer region 60, and transfers the upper wafer W1 and the lower wafer W2 to predetermined devices in the first processing block G1, the second processing block G2, and the third processing block G3 adjacent to the transfer region 60. And the superposed wafer T is transported.

  In addition, as illustrated in FIG. 1, the bonding system 1 includes a control device 70. The control device 70 controls the operation of the bonding system 1. The control device 70 is a computer, for example, and includes a control unit and a storage unit (not shown). The control unit includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), an input / output port, and various circuits. The CPU of such a microcomputer realizes control to be described later by reading and executing a program stored in the ROM. The storage unit is realized by, for example, a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk.

  Note that such a program may be recorded on a computer-readable recording medium and may be installed in the storage unit of the control device 70 from the recording medium. Examples of the computer-readable recording medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

<2. Structure of joining device>
Next, the structure of the joining apparatus 41 is demonstrated with reference to FIG. 4 and FIG. FIG. 4 is a schematic plan view showing the configuration of the joining device 41. FIG. 5 is a schematic side view showing the configuration of the joining device 41.

  As shown in FIG. 4, the joining apparatus 41 includes a processing container 100 that can seal the inside. A loading / unloading port 101 for the upper wafer W <b> 1, the lower wafer W <b> 2, and the overlapped wafer T is formed on the side surface of the processing container 100 on the transfer region 60 side, and an opening / closing shutter 102 is provided at the loading / unloading port 101.

  The inside of the processing container 100 is partitioned by the inner wall 103 into a transport area T1 and a processing area T2. The loading / unloading port 101 described above is formed on the side surface of the processing container 100 in the transfer region T1. In addition, a carry-in / out port 104 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is also formed on the inner wall 103.

  In the transfer region T1, the transition 110, the wafer transfer mechanism 111, the reversing mechanism 130, and the position adjusting mechanism 120 are arranged in this order from the loading / unloading port 101 side, for example.

  The transition 110 temporarily places the upper wafer W1, the lower wafer W2, and the superposed wafer T. The transition 110 is formed, for example, in two stages, and any two of the upper wafer W1, the lower wafer W2, and the superposed wafer T can be placed simultaneously.

  As shown in FIGS. 4 and 5, the wafer transfer mechanism 111 has, for example, a transfer arm that is movable in the vertical direction (Z-axis direction), the horizontal direction (Y-axis direction, X-axis direction), and the vertical axis. The wafer transfer mechanism 111 can transfer the upper wafer W1, the lower wafer W2, and the overlapped wafer T within the transfer region T1 or between the transfer region T1 and the processing region T2.

  The position adjustment mechanism 120 adjusts the horizontal direction of the upper wafer W1 and the lower wafer W2. Specifically, the position adjustment mechanism 120 detects the positions of the base 121 including a holding unit (not shown) that holds and rotates the upper wafer W1 and the lower wafer W2, and the notch portions of the upper wafer W1 and the lower wafer W2. And a detection unit 122 that performs the above-described operation. The position adjusting mechanism 120 detects the positions of the notch portions of the upper wafer W1 and the lower wafer W2 using the detection unit 122 while rotating the upper wafer W1 and the lower wafer W2 held on the base 121. Adjust the position. As a result, the horizontal orientations of the upper wafer W1 and the lower wafer W2 are adjusted.

  The reversing mechanism 130 reverses the front and back surfaces of the upper wafer W1. Specifically, the reversing mechanism 130 has a holding arm 131 that holds the upper wafer W1. The holding arm 131 extends in the horizontal direction (X-axis direction). The holding arm 131 is provided with holding members 132 for holding the upper wafer W1, for example, at four locations.

  The holding arm 131 is supported by a driving unit 133 including, for example, a motor. The holding arm 131 is rotatable around the horizontal axis by the driving unit 133. The holding arm 131 is rotatable about the drive unit 133 and is movable in the horizontal direction (X-axis direction). Below the drive unit 133, for example, another drive unit (not shown) including a motor or the like is provided. By this other driving unit, the driving unit 133 can move in the vertical direction along the support pillar 134 extending in the vertical direction.

  As described above, the upper wafer W1 held by the holding member 132 can be rotated around the horizontal axis by the driving unit 133 and can be moved in the vertical direction and the horizontal direction. Further, the upper wafer W1 held by the holding member 132 can be rotated around the drive unit 133 and moved between the position adjusting mechanism 120 and an upper chuck 140 described later.

  In the processing region T2, an upper chuck 140 for sucking and holding the upper surface (non-bonding surface W1n) of the upper wafer W1 from above and a lower wafer W2 are placed and the lower surface (non-bonding surface W2n) of the lower wafer W2 is viewed from below. A lower chuck 141 for sucking and holding is provided. The lower chuck 141 is provided below the upper chuck 140 and is configured to be disposed so as to face the upper chuck 140.

  As shown in FIG. 5, the upper chuck 140 is held by an upper chuck holding portion 150 provided above the upper chuck 140. The upper chuck holding unit 150 is provided on the ceiling surface of the processing container 100. The upper chuck 140 is fixed to the processing container 100 via the upper chuck holding unit 150.

  The upper chuck holding unit 150 is provided with an upper imaging unit 151 that images the upper surface (bonding surface W2j) of the lower wafer W2 held by the lower chuck 141. For the upper imaging unit 151, for example, a CCD (Charge Coupled Device) camera is used.

  The lower chuck 141 is supported by a first lower chuck moving unit 160 provided below the lower chuck 141. The first lower chuck moving unit 160 moves the lower chuck 141 in the horizontal direction (X-axis direction) as will be described later. The first lower chuck moving unit 160 is configured to be able to move the lower chuck 141 in the vertical direction and to rotate about the vertical axis. The first lower chuck moving unit 160 is an example of a second lifting unit that moves the lower chuck 141 up and down.

  The first lower chuck moving unit 160 is provided with a lower imaging unit 161 that images the lower surface (bonding surface W1j) of the upper wafer W1 held by the upper chuck 140 (see FIG. 5). For the lower imaging unit 161, for example, a CCD camera is used.

  The first lower chuck moving unit 160 is provided on the lower surface side of the first lower chuck moving unit 160 and is attached to a pair of rails 162 and 162 extending in the horizontal direction (X-axis direction). The first lower chuck moving unit 160 is configured to be movable along the rail 162.

  The pair of rails 162 and 162 are disposed on the second lower chuck moving portion 163. The second lower chuck moving unit 163 is provided on the lower surface side of the second lower chuck moving unit 163 and is attached to a pair of rails 164 and 164 extending in the horizontal direction (Y-axis direction). The second lower chuck moving unit 163 is configured to be movable in the horizontal direction (Y-axis direction) along the rail 164. The pair of rails 164 and 164 are disposed on a mounting table 165 provided on the bottom surface of the processing container 100, for example.

  Next, detailed configurations of the upper chuck 140 and the lower chuck 141 of the bonding apparatus 41 will be described with reference to FIG. FIG. 6 is a schematic cross-sectional side view showing the configuration of the upper chuck 140 and the lower chuck 141.

  As shown in FIG. 6, the upper chuck 140 has a main body 170 having the same diameter as the upper wafer W1 or a larger diameter than the upper wafer W1.

  The main body 170 is supported by the support member 180 of the upper chuck holding unit 150. The support member 180 is provided so as to cover at least the upper surface of the main body 170 in a plan view, and is fixed to the main body 170 by, for example, screwing. The support member 180 is supported by a plurality of support columns 181 (see FIG. 5) provided on the ceiling surface of the processing container 100, for example.

  A through hole 178 penetrating the support member 180 and the main body 170 in the vertical direction is formed at the center of the support member 180 and the main body 170. The position of the through hole 178 corresponds to the center portion of the upper wafer W <b> 1 that is sucked and held by the upper chuck 140. The pressing pin 191 of the striker 190 is inserted through the through hole 178.

  The striker 190 is disposed on the upper surface of the support member 180 and includes a pressing pin 191, an actuator unit 192, and a linear motion mechanism 193. The pressing pin 191 is a cylindrical member extending along the vertical direction and is supported by the actuator unit 192.

  The actuator unit 192 generates a constant pressure in a certain direction (here, vertically downward) by air supplied from, for example, an electropneumatic regulator (not shown). The actuator portion 192 can control the pressing load applied to the center portion of the upper wafer W1 by contacting the center portion of the upper wafer W1 with the air supplied from the electropneumatic regulator. The tip of the actuator part 192 is vertically movable through the through-hole 178 by air from the electropneumatic regulator.

  The actuator unit 192 is supported by the linear motion mechanism 193. The linear motion mechanism 193 moves the actuator unit 192 in the vertical direction by, for example, a drive unit incorporating a motor.

  The striker 190 configured as described above controls the movement of the actuator unit 192 by the linear motion mechanism 193, and controls the pressing load of the upper wafer W1 by the pressing pin 191 by the actuator unit 192.

  A plurality of pins 171 that are in contact with the back surface (non-bonding surface W1n) of the upper wafer W1 are provided on the lower surface of the main body 170. A rib 172 is provided on the lower surface of the main body 170 to support the outer periphery of the back surface (non-bonding surface W1n) of the upper wafer W1. The rib 172 is annularly provided outside the plurality of pins 171.

  Further, another rib 173 is provided inside the rib 172 on the lower surface of the main body 170. The rib 173 is annularly provided concentrically with the rib 172. The area inside the rib 172 is partitioned into a first suction area 174 a inside the rib 173 and a second suction area 174 b outside the rib 173.

  A plurality of suction tubes 175a are provided in the first suction region 174a. A vacuum pump 177a is connected to the plurality of suction pipes 175a via a pressure regulator 176a. The second suction region 174b is provided with a plurality of suction tubes 175b. A vacuum pump 177b is connected to the plurality of suction pipes 175b via a pressure regulator 176b.

  Then, the suction areas 174a and 174b formed surrounded by the upper wafer W1, the main body 170 and the ribs 172 are evacuated through the suction pipes 175a and 175b, respectively, and the suction areas 174a and 174b are decompressed. At this time, since the atmosphere outside the suction regions 174a and 174b is atmospheric pressure, the upper wafer W1 is pushed toward the suction regions 174a and 174b by the amount of the reduced pressure, and the upper wafer W1 is attracted to the upper chuck 140. Retained. The upper chuck 140 can evacuate the upper wafer W1 for each of the first suction region 174a and the second suction region 174b.

  In this case, since the rib 172 supports the outer peripheral portion of the back surface (non-bonded surface W1n) of the upper wafer W1, the upper wafer W1 is appropriately evacuated to the outer peripheral portion. For this reason, the entire surface of the upper wafer W1 is sucked and held by the upper chuck 140, and the flatness of the upper wafer W1 can be reduced to make the upper wafer W1 flat.

  In addition, since the height of the plurality of pins 171 is uniform, the flatness of the lower surface of the upper chuck 140 can be further reduced. As described above, the lower surface of the upper chuck 140 is flattened (the flatness of the lower surface is reduced), and the vertical distortion of the upper wafer W1 held by the upper chuck 140 can be suppressed. Further, since the back surface (non-bonded surface W1n) of the upper wafer W1 is supported by a plurality of pins 171, when the upper wafer W1 is evacuated by the upper chuck 140, the upper wafer W1 is easily peeled off from the upper chuck 140. Become.

  Next, the configuration of the lower chuck 141 will be described. As with the upper chuck 140, a pin chuck system is adopted for the lower chuck 141. The lower chuck 141 has a main body 250 having the same diameter as that of the lower wafer W2 or a diameter larger than that of the lower wafer W2. A plurality of pins 251 that are in contact with the back surface (non-bonding surface W2n) of the lower wafer W2 are provided on the upper surface of the main body 250. A rib 252 that supports the outer peripheral portion of the back surface (non-bonding surface W2n) of the lower wafer W2 is provided on the upper surface of the main body 250. The ribs 252 are provided in an annular shape outside the plurality of pins 251.

  A plurality of suction pipes 255 are provided in a region inside the main body 250 from the rib 252. The plurality of suction pipes 255 are connected to the vacuum pump 257 via the pressure regulator 256.

  Then, the suction region 254 formed by being surrounded by the lower wafer W <b> 2, the main body portion 250, and the rib 252 is evacuated through a plurality of suction pipes 255 to reduce the pressure. At this time, since the atmosphere outside the suction region 254 is atmospheric pressure, the lower wafer W2 is pushed to the suction region 254 side by the atmospheric pressure by the amount of the reduced pressure, and the lower wafer W2 is sucked and held horizontally by the lower chuck 141. The

  In this case, since the rib 252 supports the outer peripheral portion of the back surface of the lower wafer W2, the lower wafer W2 is appropriately evacuated to the outer peripheral portion. Therefore, the entire surface of the lower wafer W2 is attracted and held by the lower chuck 141, and the flatness of the lower wafer W2 can be reduced and the lower wafer W2 can be made flat. Further, since the back surface of the lower wafer W2 is supported by a plurality of pins 251, the lower wafer W2 is easily peeled off from the lower chuck 141 when releasing the vacuuming of the lower wafer W2 by the lower chuck 141.

  Further, the bonding apparatus 41 includes a deforming unit 300 that deforms the outer peripheral portion of the lower wafer W2 attracted and held by the lower chuck 141 along the in-plane direction of the lower wafer W2.

  The bonding apparatus 41 according to the embodiment uses the air pressure to deform the lower chuck 141 along the in-plane direction (that is, the horizontal direction) of the lower wafer W <b> 2, so that the lower wafer W attracted and held by the lower chuck 141 is surfaced. Deform along the inward direction.

  Note that the outer peripheral portion of the lower wafer W2 refers to, for example, a range of 20 mm from the outer edge of the lower wafer W2.

  Here, the structure of the deformation | transformation part 300 is demonstrated with reference to FIG. 6 and FIG. FIG. 7 is a schematic plan view showing the configuration of the deforming unit 300.

  As shown in FIG. 6, the deforming part 300 includes a cavity part 310, a pressure adjusting part 320, and a connecting pipe 330.

  The cavity 310 is formed inside the main body 250. Specifically, as shown in FIG. 7, the cavity 310 has an annular inner space 311 along the circumferential direction of the lower wafer W <b> 2, and is arranged concentrically with the ribs 252 on the outer periphery of the main body 250. Is done.

  The pressure adjusting unit 320 is connected to the cavity 310 through the connection pipe 330 and adjusts the pressure in the cavity 310. Specifically, the pressure adjustment unit 320 includes an air supply unit 321 that supplies compressed gas (here, compressed air) to the inside of the cavity 310, and an exhaust unit 322 that exhausts the inside of the cavity 310. . The air supply unit 321 is, for example, a compressor, and the exhaust unit 322 is, for example, a vacuum pump.

  Here, an example in which the air supply part 321 and the exhaust part 322 are connected to a common connection pipe 330 is shown, but the air supply part 321 and the exhaust part 322 are respectively connected to the cavity part 310 via different connection pipes. May be connected.

  Next, an operation example of the deforming unit 300 will be described with reference to FIGS. 8A and 8B. 8A and 8B are schematic enlarged views of the H portion shown in FIG.

  As shown in FIG. 8A, the cavity portion 310 is a main body portion of the lower chuck 141 when viewed along the circumferential direction of the lower wafer W2 (that is, when viewed from the front side to the rear side in FIG. 8A). It has a long shape in the thickness direction of 250, that is, the vertical direction. Specifically, the cavity 310 has an oval shape, preferably an elliptical shape.

  The deforming unit 300 pressurizes the internal space 311 by supplying compressed air to the internal space 311 of the cavity 310 using the air supply unit 321. Thereby, the cavity part 310 expands, and the main body part 250 of the lower chuck 141 containing the cavity part 310 expands accordingly. At this time, the rib 252 and the pins 251 provided on the main body 250 are displaced outward in the radial direction of the main body 250 as the main body 250 is expanded, so that the lower wafer held by the lower chuck 141 is held. The outer periphery of W2 can be extended.

  Usually, when an object is pressurized from the inside, the object tends to approach a perfect circle. For this reason, by making the cavity part 310 long in the thickness direction of the main body part 250, the radial direction orthogonal to the thickness direction of the main body part 250 out of the deformation amount of the cavity part 310 when the internal space 311 is pressurized. The amount of deformation can be increased compared to the amount of deformation of the main body 250 in the thickness direction.

  Therefore, according to the deformation part 300, the cavity part 310 can be expanded while suppressing the deformation amount of the main body part 250 in the thickness direction. That is, the outer peripheral portion of the lower wafer W2 can be extended while maintaining the flatness of the lower wafer W2.

  The cavity 310 is preferably oval. This is because by adopting an oval shape, pressure is more evenly applied to the cavity 310, and the strength of the main body 250 can be easily maintained. Preferably, the cavity 310 has an elliptical shape that is long in the thickness direction of the main body 250.

  The cavity 310 is disposed on the inner peripheral side of the rib 252. Thereby, when the cavity part 310 is expanded, the rib 252 and the pin 251 which are located in the outer peripheral side of the cavity part 310 can be displaced toward the outer side of the main body part 250 in the radial direction. Further, even if the cavity 310 is expanded, the pin 251 located on the inner peripheral side of the cavity 310 is hardly displaced. Therefore, according to the deforming part 300, only the outer peripheral part of the lower wafer W2 can be extended along the in-plane direction of the lower wafer W2.

  On the other hand, as illustrated in FIG. 8B, the deforming unit 300 evacuates the cavity 310 using the exhaust unit 322 to decompress the internal space 311 of the cavity 310. As the internal space 311 is depressurized, the cavity 310 contracts, and the outer periphery of the main body 250 contracts as the cavity 310 contracts. As a result, the ribs 252 and the pins 251 located on the outer peripheral side of the cavity portion 310 are displaced toward the inner side in the radial direction of the main body portion 250, and the outer peripheral portion of the lower wafer W2 attracted and held by the lower chuck 141 is the lower wafer W2. Shrink along the in-plane direction.

  As described above, the deforming unit 300 pressurizes the cavity 310 using the compressed air supplied from the air supply unit 321 to extend the outer peripheral portion of the lower chuck 141, thereby lowering the lower chuck 141 held by the lower chuck 141. The outer periphery of the wafer W2 can be extended. Further, the deforming part 300 contracts the outer peripheral part of the lower wafer W2 attracted and held by the lower chuck 141 by contracting the outer peripheral part of the lower chuck 141 by reducing the pressure of the cavity 310 using the exhaust part 322. Can do.

<3. Specific operation of joining system>
Next, a specific operation of the bonding system 1 will be described with reference to FIG. 9 and FIGS. 10A to 10G. FIG. 9 is a flowchart showing a part of the processing executed by the joining system 1. 10A to 10G are diagrams for explaining the operation of the bonding process. The various processes shown in FIG. 9 are executed based on control by the control device 70.

  First, a cassette C1 containing a plurality of upper wafers W1, a cassette C2 containing a plurality of lower wafers W2, and an empty cassette C3 are placed on a predetermined placement plate 11 of the carry-in / out station 2. Thereafter, the upper wafer W1 in the cassette C1 is taken out by the transfer device 22 and transferred to the transition device 50 of the third processing block G3 of the processing station 3.

  Next, the upper wafer W1 is transferred by the transfer device 61 to the surface modification device 30 of the first processing block G1. In the surface reforming apparatus 30, oxygen gas, which is a processing gas, is excited and turned into plasma and ionized under a predetermined reduced-pressure atmosphere. The oxygen ion is irradiated onto the bonding surface W1j of the upper wafer W1, and the bonding surface W1j is subjected to plasma processing. Thereby, the bonding surface W1j of the upper wafer W1 is modified (step S101).

  Next, the upper wafer W1 is transferred by the transfer device 61 to the surface hydrophilizing device 40 of the second processing block G2. In the surface hydrophilizing device 40, pure water is supplied onto the upper wafer W1 while rotating the upper wafer W1 held by the spin chuck. Then, the supplied pure water diffuses on the bonding surface W1j of the upper wafer W1, and a hydroxyl group (silanol group) adheres to the bonding surface W1j of the upper wafer W1 modified by the surface modifying device 30. W1j is hydrophilized. Further, the bonding surface W1j of the upper wafer W1 is cleaned with the pure water (step S102).

  Next, the upper wafer W1 is transferred by the transfer device 61 to the bonding device 41 of the second processing block G2. The upper wafer W <b> 1 carried into the bonding apparatus 41 is transferred to the position adjustment mechanism 120 by the wafer transfer mechanism 111 via the transition 110. Then, the horizontal adjustment of the upper wafer W1 is adjusted by the position adjustment mechanism 120 (step S103).

  Thereafter, the upper wafer W <b> 1 is delivered from the position adjustment mechanism 120 to the holding arm 131 of the reversing mechanism 130. Subsequently, in the transfer region T1, the front and back surfaces of the upper wafer W1 are reversed by reversing the holding arm 131 (step S104). That is, the bonding surface W1j of the upper wafer W1 is directed downward.

  Thereafter, the holding arm 131 of the reversing mechanism 130 rotates and moves below the upper chuck 140. Then, the upper wafer W 1 is delivered from the reversing mechanism 130 to the upper chuck 140. In the upper wafer W1, the non-bonding surface W1n is sucked and held by the upper chuck 140 with the notch portion directed in a predetermined direction (step S105).

  While the processes of steps S101 to S105 described above are performed on the upper wafer W1, the process of the lower wafer W2 is performed. First, the lower wafer W2 in the cassette C2 is taken out by the transfer device 22 and transferred to the transition device 50 of the processing station 3.

  Next, the lower wafer W2 is transferred to the surface modification device 30 by the transfer device 61, and the bonding surface W2j of the lower wafer W2 is modified (step S106). The modification of the bonding surface W2j of the lower wafer W2 in step S106 is the same as that in step S101 described above.

  Thereafter, the lower wafer W2 is transferred to the surface hydrophilizing device 40 by the transfer device 61, and the bonding surface W2j of the lower wafer W2 is hydrophilized and the bonding surface W2j is cleaned (step S107). Note that the hydrophilization and cleaning of the bonding surface W2j of the lower wafer W2 in step S107 are the same as in step S102 described above.

  Thereafter, the lower wafer W <b> 2 is transferred to the bonding apparatus 41 by the transfer device 61. The lower wafer W <b> 2 loaded into the bonding apparatus 41 is transferred to the position adjustment mechanism 120 by the wafer transfer mechanism 111 through the transition 110. Then, the horizontal adjustment of the lower wafer W2 is adjusted by the position adjustment mechanism 120 (step S108).

  Thereafter, the lower wafer W2 is transferred to the lower chuck 141 by the wafer transfer mechanism 111, and is sucked and held by the lower chuck 141 (step S109). In the lower wafer W2, the non-joint surface W2n is sucked and held by the lower chuck 141 with the notch portion directed in a predetermined direction.

  Subsequently, the distortion of the outer peripheral portion of the lower wafer W2 is corrected by the deforming portion 300 (step S110). For example, the deforming unit 300 pressurizes the cavity 310 using compressed air supplied from the air supply unit 321, thereby expanding the outer peripheral portion of the lower chuck 141 and lower wafer held by suction on the lower chuck 141. The outer periphery of W2 is extended (see FIG. 10A). Alternatively, the deforming unit 300 contracts the lower chuck 141 by reducing the pressure of the cavity 310 using the exhaust unit 322 and contracts the outer peripheral portion of the lower wafer W2 held by the lower chuck 141.

  Whether the outer peripheral portion of the lower wafer W2 is expanded or contracted is determined according to the direction of the distortion that occurs in the outer peripheral portion of the overlapped wafer T. That is, if distortion in the contraction direction occurs in the outer peripheral portion of the overlapped wafer T, the contraction in the contraction direction can be reduced by extending the outer peripheral portion of the lower wafer W2 in advance in the process of step S110. it can. On the other hand, when the strain in the stretching direction occurs in the outer peripheral portion of the overlapped wafer T, the strain in the stretching direction is reduced by shrinking the outer peripheral portion of the lower wafer W2 in advance in the process of step S110. Can do.

  Next, the horizontal position adjustment of the upper wafer W1 held by the upper chuck 140 and the lower wafer W2 held by the lower chuck 141 is performed (step S111).

  As shown in FIG. 10B, a plurality of predetermined reference points A1 to A3, for example, three reference points A1 to A3 are formed on the bonding surface W1j of the upper wafer W1, and similarly, predetermined on the bonding surface W2j of the lower wafer W2. A plurality of, for example, three reference points B1 to B3 are formed. As these reference points A1 to A3 and B1 to B3, for example, predetermined patterns formed on the upper wafer W1 and the lower wafer W2 are used, respectively. The number of reference points can be arbitrarily set.

  First, as shown in FIG. 10B, the horizontal positions of the upper imaging unit 151 and the lower imaging unit 161 are adjusted. Specifically, the lower chuck 141 is moved in the horizontal direction by the first lower chuck moving unit 160 and the second lower chuck moving unit 163 so that the lower imaging unit 161 is positioned substantially below the upper imaging unit 151. . Then, the common target X is confirmed by the upper imaging unit 151 and the lower imaging unit 161, and the horizontal position of the lower imaging unit 161 is fine so that the horizontal positions of the upper imaging unit 151 and the lower imaging unit 161 match. Adjusted.

  Next, as shown in FIG. 10C, after the lower chuck 141 is moved vertically upward by the first lower chuck moving unit 160, the horizontal positions of the upper chuck 140 and the lower chuck 141 are adjusted.

  Specifically, the reference of the bonding surface W2j of the lower wafer W2 using the upper imaging unit 151 while moving the lower chuck 141 in the horizontal direction by the first lower chuck moving unit 160 and the second lower chuck moving unit 163. The points B1 to B3 are sequentially imaged. At the same time, while moving the lower chuck 141 in the horizontal direction, the lower imaging unit 161 is used to sequentially image the reference points A1 to A3 of the bonding surface W1j of the upper wafer W1. FIG. 10C shows a state in which the upper imaging unit 151 images the reference point B1 of the lower wafer W2, and the lower imaging unit 161 images the reference point A1 of the upper wafer W1.

  The captured image data is output to the control device 70. In the control device 70, based on the image data captured by the upper imaging unit 151 and the image data captured by the lower imaging unit 161, the reference points A1 to A3 of the upper wafer W1 and the reference points B1 to B3 of the lower wafer W2. The horizontal position of the lower chuck 141 is adjusted by the first lower chuck moving unit 160 and the second lower chuck moving unit 163 so that the two match each other. Thus, the horizontal positions of the upper chuck 140 and the lower chuck 141 are adjusted, and the horizontal positions of the upper wafer W1 and the lower wafer W2 are adjusted.

  Next, as shown in FIG. 10D, the lower chuck 141 is moved vertically upward by the first lower chuck moving unit 160 to adjust the vertical position of the upper chuck 140 and the lower chuck 141, and the upper chuck is moved. The vertical position of the upper wafer W1 held by 140 and the lower wafer W2 held by the lower chuck 141 is adjusted (step S112). At this time, the interval between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 is a predetermined distance, for example, 80 μm to 200 μm.

  Next, the upper wafer W1 held by the upper chuck 140 and the lower wafer W2 held by the lower chuck 141 are joined (step S113). The state in which the outer peripheral portion of the lower wafer W2 is expanded or contracted by the deforming unit 300 is continued until the bonding process is completed.

  First, as shown in FIG. 10E, after the vacuum pump 177a (see FIG. 6) is stopped and the suction holding of the upper wafer W1 in the first suction region 174a is released, the pressing pin 191 of the striker 190 is lowered. Thus, the central portion of the upper wafer W1 is pushed down, and the central portion of the upper wafer W1 and the central portion of the lower wafer W2 are brought into contact with each other and pressed.

  Thereby, joining starts between the pressed center portion of the upper wafer W1 and the center portion of the lower wafer W2. Specifically, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified in steps S101 and S106, respectively, first, the van der Waals force (intermolecular) between the bonding surfaces W1j and W2j. Force) is generated, and the joint surfaces W1j and W2j are joined together. Further, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are hydrophilized in steps S102 and S107, respectively, the hydrophilic groups between the bonding surfaces W1j and W2j are hydrogen-bonded, and the bonding surfaces W1j and W2j. They are firmly joined together.

  Thereafter, as shown in FIG. 10F, the bonding area between the upper wafer W1 and the lower wafer W2 expands from the center of the upper wafer W1 and the lower wafer W2 to the outer peripheral portion.

  After that, as shown in FIG. 10G, the operation of the vacuum pump 177b (see FIG. 6) is stopped, and the suction holding of the upper wafer W1 in the second suction region 174b is released. Then, the outer periphery of the upper wafer W1 falls on the lower wafer W2. 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 with each other, and the upper wafer W1 and the lower wafer W2 are bonded.

  Thereafter, the superposed wafer T is transferred to the transition device 51 by the transfer device 61 and then transferred to the cassette C3 by the transfer device 22 of the carry-in / out station 2. In this way, a series of joining processing is completed.

  As described above, the bonding apparatus 41 according to the embodiment includes the upper chuck 140 (an example of the first holding unit), the lower chuck 141 (an example of the second holding unit), the striker 190, and the deformation unit 300. Prepare. The upper chuck 140 sucks and holds the upper wafer W1 (an example of the first substrate) from above. The lower chuck 141 sucks and holds the lower wafer W2 from below. The striker 190 presses the center portion of the upper wafer W1 from above to bring it into contact with the lower wafer W2. The deforming unit 300 deforms at least a part of the outer peripheral portion of the lower wafer W2 attracted and held by the lower chuck 141 along the in-plane direction of the lower wafer W2.

  Therefore, according to the bonding apparatus 41 according to the embodiment, local distortion generated in the outer peripheral portion of the overlapped wafer T can be reduced.

<4. First Modification>
Next, a modified example of the joining device 41 will be described. First, a first modification will be described with reference to FIG. FIG. 11 is a schematic plan view showing the configuration of the deforming portion according to the first modification. In the following description, parts that are the same as those already described are given the same reference numerals as those already described, and redundant descriptions are omitted.

  In the above-described embodiment, an example in which the deformable portion 300 includes the hollow portion 310 having the annular inner space 311 has been described. That is, in the above-described embodiment, the example in which the outer peripheral portion of the lower wafer W2 is uniformly extended or contracted over the entire circumference by the deforming portion 300 has been described. However, the deforming portion may deform at least a part of the outer peripheral portion of the lower wafer W2 along the in-plane direction of the lower wafer W2.

  For example, as shown in FIG. 11, a plurality of (here, three) individual spaces 312 are arranged in the cavity 310A included in the deformable portion 300A according to the first modification along the circumferential direction of the lower wafer W2. Have Each individual space 312 is formed in an arc shape along the circumferential direction of the lower wafer W2.

  Further, the deforming unit 300A includes a pressure adjusting unit 320A that individually adjusts the pressure of each individual space 312. The pressure adjusting unit 320A includes a plurality of air supply units 321 and a plurality of exhaust units 322, and each of the air supply units 321 and each of the exhaust units 322 is connected to the individual space 312 via the connection pipe 330A.

  With this configuration, for example, compressed air from the air supply unit 321 is supplied to any one of the plurality of individual spaces 312, and only a part of the outer peripheral portion of the lower wafer W <b> 2 is provided on the surface of the lower wafer W <b> 2. It can be stretched along the inward direction. In addition, while supplying compressed air from the air supply unit 321 to one of the plurality of individual spaces 312, the other individual space 312 is decompressed using the exhaust unit 322, so that the outer peripheral portion of the lower wafer W <b> 2 is removed. It is also possible to contract one part while expanding another part.

  Here, the hollow portion 310A has three individual spaces 312. However, the number of the individual spaces 312 may be two, or may be four or more.

<5. Second Modification>
Next, a second modification will be described with reference to FIGS. 12A to 12C. 12A to 12C are schematic side views showing the configuration of the deforming portion according to the second modification.

  In the above-described embodiment, the cavity 310 is depressurized using the exhaust unit 322, so that the cavity 310 is contracted and the outer periphery of the lower wafer W2 is contracted. However, it is difficult to deform the cavity 310 by the exhaust part 322 as compared to deforming the cavity 310 by the air supply part 321, and depending on the performance of the exhaust part 322, it is sufficient to deform the cavity 310. It may be difficult to perform proper exhaust.

  Therefore, when it is desired to shrink the outer peripheral portion of the lower wafer W2, for example, as shown in FIG. 12A, before the lower wafer W2 is sucked and held by the lower chuck 141, compressed air is supplied from the air supply portion 321 to the cavity portion 310. Is supplied to keep the cavity 310 expanded. That is, the main body 250 of the lower chuck 141 is set in a state of being extended in advance. This process is performed, for example, between step S108 and step S109 shown in FIG.

  Thereafter, as shown in FIG. 12B, the lower wafer 141 is attracted and held by the extended lower chuck 141, and then the supply of compressed air from the air supply unit 321 is stopped as shown in FIG. 12C. As a result, the lower chuck 141 returns to the original state, and the outer peripheral portion of the lower wafer W2 attracted and held by the lower chuck 141 is contracted accordingly.

  In this way, the deforming unit 300 extends the lower chuck 141 before the lower chuck 141 sucks and holds the lower wafer W2, and after the lower chuck 141 sucks and holds the lower wafer W2, the lower chuck 141 is moved to the lower chuck 141. By releasing the stretched state, the outer peripheral portion of the lower wafer W2 can be contracted without using the exhaust portion 322. In this case, the exhaust part 322 becomes unnecessary.

<6. Third Modification>
Next, a third modification will be described with reference to FIGS. 13A and 13B. FIG. 13A and FIG. 13B are schematic side views showing the configuration of the deforming portion according to the third modification.

  As illustrated in FIG. 13A, the deformable portion 300 </ b> B according to the third modified example includes a first cavity 310 </ b> B <b> 1 disposed on the inner peripheral side of the rib 252 and a second cavity disposed on the outer peripheral side of the rib 252. Part 310B2. The first cavity 310B1 and the second cavity 310B2 are arranged concentrically with the rib 252.

  The deformable portion 300B includes a first air supply portion 321B1 that supplies compressed air into the first cavity portion 310B1, and a second air supply portion 321B2 that supplies compressed air into the second cavity portion 310B2. Is provided. The first air supply part 321B1 is connected to the first cavity part 310B1 via the first connection pipe 330B1, and the second air supply part 321B2 is connected to the second cavity via the second connection pipe 330B2. Connected to the unit 310B2.

  When the outer peripheral portion of the lower wafer W2 is expanded, the deforming portion 300B pressurizes the first cavity portion 310B1 using the first air supply portion 321B1. As a result, the lower chuck 141 is extended, and the outer peripheral portion of the lower wafer W2 attracted and held by the lower chuck 141 is extended.

  On the other hand, when the outer peripheral portion of the lower wafer W2 is contracted, as shown in FIG. 13B, the second cavity 310B2 is pressurized using the second air supply portion 321B2. As a result, the rib 252 and the plurality of pins 251 arranged on the inner peripheral side with respect to the second cavity portion 310B2 are displaced toward the center of the main body portion 250, whereby the lower wafer W2 attracted and held by the lower chuck 141. The outer periphery of the shrinkage. The first cavity 310B1 disposed on the inner peripheral side of the rib 252 absorbs deformation of the main body 250, thereby suppressing the contraction of the lower wafer W2 on the inner peripheral side with respect to the first cavity 310B1. It is done. Therefore, only the outer peripheral portion of the lower wafer W2 can be contracted.

  As described above, the deformable portion 300B is provided with the second cavity portion 310B2 on the outer peripheral side of the rib 252 and pressurizes the second cavity portion 310B2, thereby allowing the outer periphery of the lower wafer W2 to be used without using the exhaust portion 322. The part can be contracted. Also in this case, the exhaust part 322 becomes unnecessary.

<7. Fourth Modification>
Next, a fourth modification will be described with reference to FIG. FIG. 14 is a schematic side view illustrating a configuration of a deforming unit according to a fourth modification.

  As illustrated in FIG. 14, the deformation unit 300 </ b> C according to the fourth modification includes a heating unit 350 (an example of a temperature adjustment unit) and a cooling unit 360. The heating unit 350 is a resistance heater such as a ceramic heater, and is provided in the main body 250 of the lower chuck 141. The heating unit 350 has an annular shape along the circumferential direction of the lower wafer W2, for example, and is disposed below the outer peripheral portion of the lower wafer W2 that is sucked and held by the lower chuck 141.

  The cooling unit 360 includes a flow path 361 formed inside the main body 250 and a supply pipe 362 that connects the flow path 361 to the cooling water supply source 370. The channel 361 has an annular shape along the circumferential direction of the lower wafer W <b> 2, and is disposed adjacent to the heating unit 350 on the inner peripheral side of the heating unit 350. The cooling water (for example, water) supplied from the cooling water supply source 370 is supplied to the flow path 361 via the supply pipe 362, whereby the main body 250 is cooled.

  Further, in the fourth modified example, the plurality of pins 251 include outer peripheral pins 251C1 that are in contact with the outer peripheral portion of the lower wafer W2, and inner peripheral pins 251C2 that are disposed on the inner peripheral side of the outer peripheral pins 251C1. .

  The outer peripheral side pin 251C1 has a DLC (Diamond-Like Carbon) coating at least on the top. Thereby, the outer peripheral side pin 251C1 has a lower friction coefficient than the inner peripheral side pin 251C2. The upper surface of the rib 252 is similarly DLC coated, and the rib 252 has a lower friction coefficient than the inner peripheral side pin 251C2.

  The deforming portion 300C is configured as described above, and by heating the outer peripheral portion of the lower wafer W2 using the heating unit 350, the outer peripheral portion of the lower wafer W2 is thermally expanded to achieve the in-plane direction of the lower wafer W2. Stretch along. Of the heat generated by the heating unit 350, the heat propagated to the inner peripheral side of the main body 250 is absorbed by the cooling water flowing through the flow path 361. Thereby, since the propagation of heat to the inner peripheral side of the cooling unit 360 is suppressed, only the lower wafer W2 can be expanded.

  Normally, even if the lower wafer W2 attracted and held by the lower chuck 141 is heated, the lower wafer W2 is not deformed or hardly deformed because it is in a state of being restrained by the lower chuck 141. On the other hand, in the fourth modification, the upper surfaces of the outer peripheral side pins 251C1 and the ribs 252 that are in contact with the outer peripheral portion of the lower wafer W2 are reduced in friction by DLC coating. For this reason, even when the lower wafer W2 is sucked and held, the outer peripheral portion of the lower wafer W2 can be extended by heating.

  The DLC coating has excellent friction and corrosion resistance, and it is difficult for the mating material (lower wafer W2) to be worn or damaged during friction, and it is difficult to cause a chemical reaction with the mating material during friction. This is effective as means for reducing friction between the side pin 251C1 and the rib 252. However, the means for reducing the friction of the outer peripheral side pin 251C1 and the rib 252 is not limited to DLC coating. For example, the outer peripheral side pin 251C1 may be formed of a material having a smaller friction coefficient than the inner peripheral side pin 251C2.

<8. Fifth Modification>
Next, a fifth modification will be described with reference to FIG. FIG. 15 is a schematic side view showing the configuration of the deforming portion according to the fifth modification.

  In the fourth modification described above, an example in which the heating unit 350 is provided inside the main body 250 of the lower chuck 141 has been described. However, the heating unit is located above the lower wafer W2 that is attracted and held by the lower chuck 141. May be arranged.

  For example, as illustrated in FIG. 15, a deforming unit 300 </ b> D according to the fifth modification includes a heating unit 355 (an example of a temperature adjusting unit) and a cooling unit 360.

  The heating unit 355 is, for example, a nozzle that supplies a gas, and is disposed above the outer peripheral portion of the lower wafer W2, and supplies the warm air toward the outer peripheral portion of the lower wafer W2, whereby the outer peripheral portion of the lower wafer W2 Heat.

  As described above, the heating unit 355 is not necessarily provided inside the main body 250 of the lower chuck 141 and may be disposed above the lower wafer W <b> 2 attracted and held by the lower chuck 141. The heating unit 355 does not necessarily need to be a nozzle that supplies gas, and may be a resistance heater, a lamp heater, or the like.

  Here, an example in which the outer peripheral portion of the lower wafer W2 is extended by heating the outer peripheral portion of the lower wafer W2 has been described. However, the deforming unit 300D is replaced with the outer periphery of the lower wafer W2 instead of the heating unit 355. A cooling unit (an example of a temperature adjusting unit) for cooling the unit may be provided. As the cooling unit, for example, a nozzle that is disposed above the outer peripheral portion of the lower wafer W2 and supplies cold air toward the outer peripheral portion of the lower wafer W2 can be used.

  Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

W1 Upper wafer W2 Lower wafer T Superposition wafer 1 Bonding system 30 Surface modification device 40 Surface hydrophilization device 41 Bonding device 70 Control device 140 Upper chuck 141 Lower chuck 250 Body portion 251 Pin 300 Deformation portion 310 Cavity portion 320 Pressure adjustment portion 321 Air supply part 322 Exhaust part 330 Connection pipe

Claims (9)

A first holding unit that holds the first substrate by suction from above;
A second holding unit that holds the second substrate by suction from below;
A striker that presses the center of the first substrate from above to contact the second substrate;
A bonding apparatus comprising: a deforming unit that deforms at least a part of an outer peripheral portion of the second substrate held by suction by the second holding unit along an in-plane direction of the second substrate. The second holding part is
A main body for evacuating the second substrate;
A plurality of pins provided on the main body and in contact with the lower surface of the second substrate;
The deformation part is
A cavity formed inside the main body,
The bonding apparatus according to claim 1, further comprising: a pressure adjusting unit that adjusts the pressure in the cavity. The cavity is
The bonding apparatus according to claim 2, wherein when viewed along a circumferential direction of the second substrate, the bonding apparatus has a long circular shape in the thickness direction of the main body. The second holding part is
An annular rib disposed on the outer peripheral side of the main body part with respect to the plurality of pins,
The cavity is
The bonding apparatus according to claim 2, wherein the bonding apparatus is disposed on an inner peripheral side of the rib. The cavity is
The bonding apparatus according to claim 2, further comprising an annular internal space along a circumferential direction of the second substrate. The cavity is
A plurality of individual spaces arranged side by side along the circumferential direction of the second substrate;
The pressure adjusting unit is
The joining device according to claim 2, further comprising a plurality of air supply units connected to each of the plurality of individual spaces. The second holding part is
A main body for evacuating the second substrate;
A plurality of pins provided on the main body and in contact with the lower surface of the second substrate;
The deformation part is
A temperature adjusting part for adjusting the temperature of the outer peripheral part of the second substrate;
The outer peripheral side pin which contacts the outer peripheral part of the said 2nd board | substrate among these pins has a low coefficient of friction compared with pins other than the said outer peripheral side pin among these pins. The joining apparatus as described. The outer peripheral side pin is
The bonding apparatus according to claim 7, wherein at least a top part is provided with a DLC (Diamond-Like Carbon) coating. A bonding method for bonding substrates,
A first holding step for sucking and holding the first substrate from above, using a first holding portion for sucking and holding the first substrate from above;
A second holding step for sucking and holding the second substrate from below by using a second holding portion for sucking and holding the second substrate from below;
Using a deforming portion that deforms at least a part of the outer peripheral portion of the second substrate held by suction to the second holding portion along the in-plane direction of the second substrate, the second holding portion is sucked and held by the second holding portion. A deformation step of deforming at least a part of the outer peripheral portion of the second substrate along the in-plane direction of the second substrate;
After the deformation step, using a striker that presses the central portion of the first substrate from above to make contact with the second substrate, and makes contact with the second substrate by pressing the central portion of the first substrate from above. A bonding method comprising the steps of:

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