JP6640546B2 - Joining apparatus, joining system and joining method - Google Patents

Description

  The disclosed embodiments relate to a joining apparatus, a joining system, and a joining method.

  2. Description of the Related Art Conventionally, as a bonding device for bonding substrates such as semiconductor wafers, a bonding device for bonding substrates by intermolecular force is known.

  In this type of bonding apparatus, two substrates whose surfaces have been modified and hydrophilically arranged are vertically opposed to each other, and a central portion of a substrate arranged above (hereinafter, referred to as an upper substrate) is pushed down with a pin, It is brought into contact with the center of a substrate disposed below (hereinafter referred to as a lower substrate). As a result, first, the center of the upper substrate and the center of the lower substrate are joined by an intermolecular force, and further, the joining region expands from the center to the outer periphery, so that the upper substrate and the lower substrate are joined. (See Patent Document 1).

JP 2014-229677 A

  However, in the above-described conventional technology, since the method of pressing down the center portion of the upper substrate with a pin is adopted, the upper substrate is bonded to the lower substrate in a deformed state, so that the bonded substrate is Distortion may occur.

  An object of one embodiment of the present invention is to provide a bonding apparatus, a bonding system, and a bonding method that can reduce distortion generated in a substrate after bonding.

  A joining device according to an aspect of an embodiment includes a first holding unit, a second holding unit, a pushing unit, and a structure for canceling a difference in deformation amount due to anisotropy of Young's modulus. The first holding unit sucks and holds the first substrate of the two substrates including the substrate having the anisotropic Young's modulus on the lower surface. The second holding unit is provided below the first holding unit, and sucks and holds the second substrate of the two substrates on the upper surface. The pressing portion presses the central portion of the first substrate from above to contact the second substrate. The structure for canceling the difference in the amount of deformation due to the anisotropy of the Young's modulus is based on the anisotropy of the Young's modulus among the difference in the amount of deformation between the first substrate and the second substrate caused by the pressing of the first substrate. Cancels out the difference in the amount of deformation associated with

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

FIG. 1 is an explanatory diagram of a joining method according to the embodiment. FIG. 2 is a diagram for explaining a difference in the amount of deformation between the first substrate and the second substrate. FIG. 3 is a schematic plan view showing the configuration of the joining system according to the first embodiment. FIG. 4 is a schematic side view showing the configuration of the joining system according to the first embodiment. FIG. 5 is a schematic side view of the upper wafer and the lower wafer. FIG. 6 is a schematic plan view showing the configuration of the joining device. FIG. 7 is a schematic side view showing the configuration of the joining device. FIG. 8 is a schematic side view showing the configuration of the position adjusting mechanism. FIG. 9 is a schematic plan view showing the configuration of the reversing mechanism. FIG. 10 is a schematic side view (part 1) illustrating the configuration of the reversing mechanism. FIG. 11 is a schematic side view (part 2) illustrating the configuration of the reversing mechanism. FIG. 12 is a schematic side view showing the configuration of the holding arm and the holding member. FIG. 13 is a schematic side view showing the internal configuration of the joining device. FIG. 14 is a diagram showing the crystal directions of the upper wafer and the lower wafer. FIG. 15 is a diagram showing a relationship between the crystal directions of the upper wafer and the lower wafer and the Young's modulus. FIG. 16 is a schematic side view showing the configuration of the upper chuck and the lower chuck. FIG. 17 is a schematic plan view when the upper chuck is viewed from below. FIG. 18 is a schematic plan view showing an example of the shape of the upper surface of the lower chuck. FIG. 19 is a schematic plan view showing an example of the suction area of the lower chuck. FIG. 20 is a flowchart illustrating an example of the lower wafer suction process. FIG. 21 is a diagram for explaining a difference in the amount of deformation between the upper wafer and the lower wafer according to the first embodiment. FIG. 22 is a schematic side view showing the shape of the upper surface of the lower chuck according to the first modification. FIG. 23 is a schematic side view showing the shape of the upper surface of the lower chuck according to the second modification. FIG. 24 is a flowchart illustrating a part of a process executed by the joining system. FIG. 25 is a schematic side view showing the configuration of the upper chuck and the lower chuck according to the second embodiment. FIG. 26 is a schematic plan view when the upper chuck according to the second embodiment is viewed from below. FIG. 27 is a flowchart illustrating an example of the upper wafer suction release processing. FIG. 28 is a diagram for explaining a difference in the amount of deformation between the upper wafer and the lower wafer according to the second embodiment. FIG. 29 is a diagram illustrating an example of a configuration of a pressing member included in the joining device according to the third embodiment.

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

<1. Joining method>
First, a bonding method according to an embodiment will be described with reference to FIGS. FIG. 1 is an explanatory diagram of a joining method according to the embodiment. FIG. 2 is a diagram for explaining a difference in the amount of deformation between the first substrate and the second substrate. In each of the drawings referred to below, an orthogonal coordinate system in which a vertically upward direction is the positive direction of the Z-axis may be shown for easy understanding.

  In the bonding method according to the embodiment, the first substrate W1 and the second substrate W2 are bonded by an intermolecular force. Specifically, after the surfaces to be bonded of the first substrate W1 and the second substrate W2 are hydrophilized and modified, the first substrate W1 is adsorbed on the lower surface of the upper chuck 230 as shown in the upper diagram of FIG. The second substrate W2 is suction-held on the upper surface of the lower chuck 231.

  Subsequently, the center of the first substrate W1 is pushed down using the push pins 251 to make contact with the center of the second substrate W2. Thereby, as shown in the lower diagram of FIG. 1, first, the central part of the first substrate W1 and the central part of the second substrate W2 are joined by an intermolecular force. Thereafter, the first substrate W1 and the second substrate W2 are bonded by expanding the bonding region between the first substrate W1 and the second substrate W2 from the center to the outer periphery.

  As described above, the bonding method according to the embodiment employs a method in which the center of the first substrate W1 is pushed down by the push pins 251. For this reason, as shown in FIG. 2, the first substrate W1 is joined to the second substrate W2 in a state of being entirely extended. The amount of extension of the first substrate W1 is, for example, about 1 to 2 μm when the diameter is 300 mm.

  Here, the present inventors have discovered that the first substrate W1 does not have a perfect circular shape but extends non-uniformly as shown in FIG. As a result of intensive studies, the present inventors have found that the cause is due to the anisotropy of the Young's modulus of the first substrate W1.

  That is, when the first substrate W1 is pressed down by the push pins 251, the first substrate W1 is deformed (elongated). For example, when the Young's modulus of the first substrate W1 is anisotropic, the deformation is caused. The present inventors have found that the amount (elongation amount) is different between a direction in which the Young's modulus is high and a direction in which the Young's modulus is low. As described above, when the first substrate W1 is bonded to the second substrate W2 in a state where the first substrate W1 is unevenly extended due to the anisotropy of the Young's modulus, the bonded substrate is distorted.

  Therefore, in the bonding method according to the embodiment, of the difference in the amount of deformation between the first substrate W1 and the second substrate W2 caused by the pressing of the first substrate W1 by the push pin 251, the deformation associated with the anisotropy of the Young's modulus. By canceling the difference in the amount, the strain generated in the bonded substrate is reduced.

  For example, the difference in the amount of deformation between the first substrate W1 and the second substrate W2 due to the anisotropy of the Young's modulus can be canceled by extending the second substrate W2 in the same manner as the first substrate W1. This will be described in the first embodiment.

  The difference in the amount of deformation between the first substrate W1 and the second substrate W2 due to the anisotropy of the Young's modulus is controlled by controlling the elongation of the first substrate W1 so that the first substrate W1 extends in a perfect circle. Can also be countered. This point will be described in the second embodiment and the third embodiment.

  Note that the bonded substrate may have distortion even when the first substrate W1 has no anisotropy in Young's modulus and the second substrate W2 has anisotropy in Young's modulus. That is, since the first substrate W1 is joined to the second substrate W2 in a state where the first substrate W1 is extended by the push pins 251, the first substrate W1 tries to return to its original state (try to shrink) after being joined to the second substrate W2. At this time, if the Young's modulus of the second substrate W2 is anisotropic, a difference occurs in the deformation amount (shrinkage amount) in the process of deforming (shrinking) along with the deformation (shrinkage) of the first substrate W1. As a result, the bonded substrate is distorted. Also in this case, it is possible to reduce the distortion generated in the bonded substrate by canceling the difference in the deformation amount due to the anisotropy of the Young's modulus.

(First embodiment)
<2. Configuration of joining system>
First, the configuration of the joining system according to the first embodiment will be described with reference to FIGS. FIG. 3 is a schematic plan view showing the configuration of the joining system according to the present embodiment, and FIG. 4 is a schematic side view of the same. FIG. 5 is a schematic side view of the upper wafer and the lower wafer.

  The bonding system 1 according to the present embodiment illustrated in FIG. 3 forms the overlapped wafer T by bonding the first substrate W1 and the second substrate W2 (see FIG. 5).

  First substrate W1 and second substrate W2 are single-crystal silicon wafers. An electronic circuit is formed on one or both of the first substrate W1 and the second substrate W2.

  Hereinafter, the first substrate W1 is described as “upper wafer W1”, and the second substrate W2 is described as “lower wafer W2”.

  Further, in the following, as shown in FIG. 5, the plate surface of the upper wafer W1 on the side bonded to the lower wafer W2 is referred to as “bonding surface W1j”, and the opposite side of the bonding surface W1j. The plate surface is referred to as “non-joining surface W1n”. Further, among the plate surfaces of the lower wafer W2, the plate surface on the side bonded to the upper wafer W1 is referred to as “bonding surface W2j”, and the plate surface on the opposite side to the bonding surface W2j is referred to as “non-bonding surface W2n”. Describe.

  Further, as shown in FIG. 3, 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 side by side in the order of the loading / unloading station 2 and the processing station 3 along the X-axis positive direction. The loading / unloading station 2 and the processing station 3 are integrally connected.

  The loading / unloading station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 includes a plurality of mounting plates 11. Cassettes C1, C2, and C3, each accommodating a plurality of (for example, 25) substrates in a horizontal state, are mounted on each mounting plate 11, respectively. For example, the cassette C1 is a cassette that stores the upper wafer W1, the cassette C2 is a cassette that stores the lower wafer W2, and the cassette C3 is a cassette that stores the overlapped wafer T.

  The transfer area 20 is arranged adjacent to the mounting table 10 on the X-axis positive direction side. In the transfer area 20, a transfer path 21 extending in the Y-axis direction and a transfer device 22 movable along the transfer path 21 are provided. The transfer device 22 is movable not only in the Y-axis direction but also in the X-axis direction and is rotatable around the Z-axis, and is provided with cassettes C1 to C3 mounted on the mounting plate 11 and a processing station 3 to be 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.

  The number of the cassettes C1 to C3 mounted on the mounting plate 11 is not limited to the illustrated one. Further, in addition to the cassettes C1, C2, and C3, a cassette or the like for collecting a failed substrate may be mounted on the mounting plate 11.

  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, a first processing block G1 is provided on the front side (the Y-axis negative direction side in FIG. 3) of the processing station 3, and the second processing block G1 is provided on the rear side (the Y-axis positive direction side in FIG. 3) of the processing station 3. A processing block G2 is provided. Further, a third processing block G3 is provided on the side of the loading / unloading station 2 of the processing station 3 (the negative side in the X-axis direction in FIG. 3).

  In the first processing block G1, a surface reforming device 30 for modifying the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 is arranged. The surface reforming device 30 cuts the bond between the SiO2 at the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 to form a single bond SiO, and then makes the bonding surfaces W1j and W1j so as to be easily hydrophilized thereafter. Modify W2j.

  In the surface reforming apparatus 30, for example, an oxygen gas as a processing gas is excited, turned into plasma, and ionized under a reduced-pressure atmosphere. Then, the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 are irradiated with the oxygen ions, whereby the bonding surfaces W1j and W2j are plasma-processed and reformed.

  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 a spin chuck. Thereby, the pure water supplied on 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 made hydrophilic. The bonding device 41 bonds the upper wafer W1 and the lower wafer W2. The configuration of the joining device 41 will be described later.

  As shown in FIG. 4, in the third processing block G3, 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 from the bottom.

  In addition, as shown in FIG. 3, 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. In the transfer area 60, a transfer device 61 is arranged. The transfer device 61 has a transfer arm that is movable, for example, vertically, horizontally, and around a vertical axis. The transfer device 61 moves in the transfer area 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 area 60. And transport the overlapped wafer T.

  In addition, as shown in FIG. 3, the joining system 1 includes a control device 70. The control device 70 controls the operation of the joining system 1. The control device 70 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output port, and various circuits. The CPU of the microcomputer reads out and executes a program stored in the ROM, thereby implementing control described later.

  Note that such a program is 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 magnet optical disk (MO), and a memory card.

<3. Configuration of joining device>
Next, the configuration of the joining device 41 will be described with reference to FIGS. FIG. 6 is a schematic plan view showing the configuration of the joining device 41, and FIG. 7 is a schematic side view of the same. FIG. 8 is a schematic side view showing the configuration of the position adjustment mechanism 210. FIG. 9 is a schematic plan view showing the configuration of the reversing mechanism 220, and FIGS. 10 and 11 are schematic side views (part 1) and (part 2). FIG. 12 is a schematic side view showing the configuration of the holding arm 221 and the holding member 222, and FIG. 13 is a schematic side view showing the internal configuration of the joining device 41.

  As shown in FIG. 6, the joining device 41 has a processing container 190 whose interior can be sealed. A loading / unloading port 191 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is formed on a side surface of the processing container 190 on the side of the transfer area 60. The loading / unloading port 191 is provided with an opening / closing shutter 192.

  The inside of the processing container 190 is partitioned by the inner wall 193 into a transport area T1 and a processing area T2. The above-described loading / unloading port 191 is formed on the side surface of the processing container 190 in the transfer area T1. In addition, a loading / unloading port 194 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is also formed on the inner wall 193.

  A transition 200 for temporarily mounting the upper wafer W1, the lower wafer W2, and the overlapped wafer T is provided on the Y-axis negative direction side of the transfer area T1. The transition 200 is formed, for example, in two stages, and can place any two of the upper wafer W1, the lower wafer W2, and the overlapped wafer T at the same time.

  The transport mechanism 201 is provided in the transport area T1. The transport mechanism 201 has a transport arm that is movable, for example, vertically, horizontally, and around a vertical axis. Then, the transfer mechanism 201 transfers the upper wafer W1, the lower wafer W2, and the overlapped wafer T within the transfer area T1 or between the transfer area T1 and the processing area T2.

  A position adjusting mechanism 210 that adjusts the horizontal direction of the upper wafer W1 and the lower wafer W2 is provided on the Y-axis positive direction side of the transfer area T1. As shown in FIG. 8, the position adjusting mechanism 210 detects the base 211, the holding unit 212 that sucks and holds the upper wafer W1 and the lower wafer W2 and rotates them, and detects the positions of the notches of the upper wafer W1 and the lower wafer W2. And a detection unit 213 that performs the operation.

  In the position adjusting mechanism 210, the detection unit 213 detects the positions of the notches of the upper wafer W1 and the lower wafer W2 while rotating the upper wafer W1 and the lower wafer W2 sucked and held by the holding unit 212. By adjusting the positions of the parts, the horizontal directions of the upper wafer W1 and the lower wafer W2 are adjusted. As a result, the upper wafer W1 and the lower wafer W2 are held by the upper chuck 230 and the lower chuck 231 in a state in which the crystal directions match each other, that is, in a state in which the direction in which extension is easy and the direction in which extension is difficult.

  In addition, a reversing mechanism 220 for reversing the front and back surfaces of the upper wafer W1 is provided in the transfer area T1. The reversing mechanism 220 has a holding arm 221 that holds the upper wafer W1, as shown in FIGS.

  The holding arm 221 extends in the horizontal direction. The holding arm 221 is provided with, for example, four holding members 222 for holding the upper wafer W1. The holding member 222 is configured to be horizontally movable with respect to the holding arm 221 as shown in FIG. A cutout 223 for holding the outer peripheral portion of the upper wafer W1 is formed on the side surface of the holding member 222. These holding members 222 can hold the upper wafer W1 therebetween.

  As shown in FIGS. 9 to 11, the holding arm 221 is supported by a first driving unit 224 provided with, for example, a motor. The holding arm 221 is rotatable around a horizontal axis by the first driving unit 224. The holding arm 221 is rotatable around the first drive unit 224 and is movable in the horizontal direction.

  Below the first drive unit 224, a second drive unit 225 including, for example, a motor is provided. The first drive section 224 is movable vertically by the second drive section 225 along the support column 226 extending in the vertical direction.

  As described above, the upper wafer W1 held by the holding member 222 can be rotated around the horizontal axis and moved in the vertical and horizontal directions by the first driving unit 224 and the second driving unit 225. it can. Further, the upper wafer W1 held by the holding member 222 can rotate around the first driving unit 224 and move between the position adjustment mechanism 210 and an upper chuck 230 described later.

  Further, as shown in FIG. 7, an upper chuck 230 and a lower chuck 231 are provided in the processing region T2. The upper chuck 230 sucks and holds the upper wafer W1 from above. Further, the lower chuck 231 is provided below the upper chuck 230, and sucks and holds the lower wafer W2 from below.

  The upper chuck 230 is supported by a support member 280 provided on the ceiling surface of the processing container 190, as shown in FIG. The support member 280 is provided with an upper imaging unit 281 (see FIG. 13) for imaging the bonding surface W2j of the lower wafer W2 held by the lower chuck 231. The upper imaging section 281 is provided adjacent to the upper chuck 230.

  6, 7, and 13, the lower chuck 231 is supported by a first lower chuck moving unit 290 provided below the lower chuck 231. The first lower chuck moving unit 290 moves the lower chuck 231 in the horizontal direction (Y-axis direction) as described later. The first lower chuck moving unit 290 is configured to be able to move the lower chuck 231 in the vertical direction and to be rotatable about a vertical axis.

  The first lower chuck moving unit 290 is provided with a lower imaging unit 291 that images the bonding surface W1j of the upper wafer W1 held by the upper chuck 230. The lower imaging unit 291 is provided adjacent to the lower chuck 231.

  As shown in FIGS. 6, 7, and 13, the first lower chuck moving unit 290 is provided on the lower surface side of the first lower chuck moving unit 290, and extends in the horizontal direction (Y-axis direction). On the rail 295. The first lower chuck moving unit 290 is configured to be movable along the rail 295.

  The pair of rails 295 are provided in the second lower chuck moving unit 296. The second lower chuck moving unit 296 is provided on the lower surface side of the second lower chuck moving unit 296, and is attached to a pair of rails 297 extending in the horizontal direction (X-axis direction). The second lower chuck moving unit 296 is configured to be movable along the rail 297, that is, to move the lower chuck 231 in the horizontal direction (X-axis direction). Note that the pair of rails 297 is provided on a mounting table 298 provided on the bottom surface of the processing container 190.

  Here, the anisotropy of the Young's modulus of the upper wafer W1 and the lower wafer W2 will be described with reference to FIGS. FIG. 14 is a diagram showing the crystal directions of the upper wafer W1 and the lower wafer W2. FIG. 15 is a diagram showing the relationship between the crystal directions of the upper wafer W1 and the lower wafer W2 and the Young's modulus. FIG. 15 shows that the Young's modulus increases as the distance from the origin O increases.

  As shown in FIG. 14, the upper wafer W1 and the lower wafer W2, which are single-crystal silicon wafers, have a surface crystal direction (direction along the positive Z-axis direction) of [100] and an in-plane direction of [100]. 110] and [1 (overline) 10]. Here, it is assumed that the [110] direction matches the X-axis positive direction, and the [1 (overline) 10] direction matches the Y-axis positive direction.

  As shown in FIG. 15, the Young's modulus of the upper wafer W1 and the lower wafer W2 is a 90 ° period (0 °, 90 °, 180 °, 270 °) when the [110] direction is 0 °. ), And the lowest in the direction of the 45 ° cycle (45 °, 135 °, 225 °, 315 ° direction).

  The inventors of the present invention have found that, for a substrate having an anisotropic Young's modulus, the deformation amount in the direction in which the Young's modulus is the highest, that is, in the direction of the 90 ° cycle, is changed in the direction in which the Young's modulus is the lowest, that is, the direction of the 45 ° cycle. Found to be larger than the amount.

  Next, configurations of the upper chuck 230 and the lower chuck 231 will be described with reference to FIGS. FIG. 16 is a schematic side view showing the configuration of the upper chuck 230 and the lower chuck 231. FIG. 17 is a schematic plan view when the upper chuck 230 is viewed from below.

  As shown in FIG. 16, the joining device 41 includes an upper chuck 230, a lower chuck 231 and a pushing mechanism 250.

  The upper chuck 230 sucks and holds the upper wafer W1 on the lower surface. As shown in FIG. 17, the lower surface of upper chuck 230 is partitioned into a plurality of, for example, two regions 230a and 230b. These regions 230a and 230b are provided in this order from the center of the upper chuck 230 toward the peripheral portion (outer peripheral portion). The area 230a has a circular shape in plan view, and the area 230b has an annular shape in plan view.

  Suction pipes 240a and 240b for sucking and holding the upper wafer W1 are independently provided in the respective areas 230a and 230b. Different vacuum pumps 241a and 241b are connected to the suction pipes 240a and 240b, respectively. As described above, the upper chuck 230 is configured to be able to set the evacuation of the upper wafer W1 for each of the regions 230a and 230b.

  The upper wafer W1 is suction-held by the upper chuck 230 such that the [110] direction matches the X-axis positive direction and the [1 (upper line) 10] direction matches the Y-axis positive direction.

  At the center of the upper chuck 230, a through hole 243 that penetrates the upper chuck 230 in the thickness direction is formed. The central portion of the upper chuck 230 corresponds to the central portion of the upper wafer W1 held by suction on the upper chuck 230. The push pin 251 of the push mechanism 250 is inserted into the through hole 243.

  The pushing mechanism 250 pushes the central portion of the upper wafer W <b> 1 sucked and held by the upper chuck 230. The pushing mechanism 250 has, for example, a cylinder structure, and includes a pushing pin 251 and an outer cylinder 252 serving as a guide when the pushing pin 251 moves up and down. The push pin 251 is vertically movable vertically through a through hole 243 by, for example, a drive unit (not shown) containing a motor.

  The lower chuck 231 sucks and holds the lower wafer W2 on the upper surface 232. The lower wafer W2 has the [110] direction coincident with the X-axis positive direction, the [1 (upper line) 10] direction coincident with the Y-axis positive direction, and the center position is Z with the center position of the upper chuck W1. The lower chuck 231 sucks and holds it so as to coincide in the axial direction.

  The upper surface 232 of the lower chuck according to the first embodiment is formed not in a planar shape but in a pyramid shape. The shape of the upper surface 232 of the lower chuck 231 will be described with reference to FIG. FIG. 18 is a schematic plan view showing an example of the shape of the upper surface 232 of the lower chuck 231.

  As shown in FIG. 18, the upper surface 232 of the lower chuck 231 has a side 232a along a direction in which the Young's modulus of the lower wafer W2 is lowest, that is, a direction of 45 ° cycle when the [110] direction is 0 °. Protrudes in the shape of a pyramid having ２232d. With such a shape, when the lower wafer W2 is attracted to the upper surface 232, the deformation amount of the lower wafer W2 can be made different between a direction in which the lower wafer W2 has the highest Young's modulus and a direction in which the lower wafer W2 has the lowest Young's modulus. Therefore, the lower wafer W2 can be extended unevenly.

  Subsequently, the suction area of the lower chuck 231 will be described with reference to FIG. FIG. 19 is a schematic plan view illustrating an example of a suction area of the lower chuck 231.

  As shown in FIG. 19, the suction area formed on the upper surface 232 of the lower wafer W2 is divided into a first suction area 231a and a second suction area 231b. The first suction region 231a is a suction region including the above-described sides 232a to 232d among the suction regions of the lower wafer W2. The second suction region 231b is a suction region of the lower wafer W2 other than the first suction region 231a.

  In the first suction area 231a and the second suction area 231b, suction pipes 260a and 260b for sucking and holding the lower wafer W2 are provided independently. Different vacuum pumps 261a and 261b are connected to the suction pipes 260a and 260b, respectively (see FIG. 16). As described above, the lower chuck 231 is configured to be able to set the evacuation of the lower wafer W2 for each of the first suction area 231a and the second suction area 231b.

  The control device 70 starts the suction of the lower wafer W2 by the first suction area 231a and the suction of the lower wafer W2 by the second suction area 231b at different timings. Here, an example of the suction processing of the lower wafer W2 by the control device 70 will be described with reference to FIGS. FIG. 20 is a flowchart illustrating an example of the suction process of the lower wafer W2. FIG. 21 is a diagram for explaining a difference in the amount of deformation between the upper wafer W1 and the lower wafer W2 according to the first embodiment.

  As shown in FIG. 20, the control device 70 first starts the suction of the lower wafer W2 by the first suction area 231a (step S101), and thereafter starts the suction of the lower wafer W2 by the second suction area 231b (step S101). Step S102).

  As described above, the control device 70 causes the lower chuck 231 to first suction-hold the portion of the lower wafer W2 along the direction of the 45 ° cycle with the lowest Young's modulus. Thereby, the portion along the direction of the 45 ° cycle is fixed to the lower chuck 231 and its elongation is suppressed. Then, in this state, the second suction region 231b starts suction holding of a portion other than the portion along the direction of the 45 ° cycle, and the portion other than the portion along the direction of the 45 ° cycle on the upper surface 232. It will be stretched according to the shape.

  Thereby, as shown in FIG. 21, the lower wafer W2 extends non-uniformly like the upper wafer W1. As a result, the difference in the amount of deformation between the upper wafer W1 and the lower wafer W2 is reduced, and the distortion generated in the bonded wafer T, which is the bonded substrate, is reduced.

  Here, an example in which the lower chuck 231 includes the pyramid-shaped upper surface 232 having the sides 232a to 232d along the direction with the lowest Young's modulus has been described, but the lower chuck 231 has the highest Young's modulus. A pyramid-shaped upper surface having sides along a direction, that is, a direction having a period of 90 ° may be provided. In this case, the control device 70 may start the suction of the lower wafer W2 by the second suction area 231b and then start the suction of the lower wafer W2 by the first suction area 231a.

  Next, a modified example of the lower chuck 231 will be described with reference to FIGS. FIG. 22 is a schematic side view showing the shape of the upper surface 232 of the lower chuck 231 according to the first modification. FIG. 23 is a schematic side view showing the shape of the upper surface 232 of the lower chuck 231 according to the second modification.

  As shown in FIG. 22, the upper surface 232 of the lower chuck 231 may have a concave pyramid surface 233. By adopting such a shape, the lower wafer W2 can be largely deformed while keeping the projection height of the upper surface 232 low.

  In addition, as shown in FIG. 23, the upper surface 232 of the lower chuck 231 may have a convex pyramid surface 234. Even with such a shape, the lower wafer W2 can be greatly deformed while keeping the height of the protrusion of the upper surface 232 low.

<4. Specific operation of joining system>
Next, a specific operation of the joining system 1 will be described with reference to FIG. FIG. 24 is a flowchart showing a part of the processing executed by the joining system 1. The various processes illustrated in FIG. 24 are executed based on control by the control device 70.

  First, a cassette C1 accommodating a plurality of upper wafers W1, a cassette C2 accommodating a plurality of lower wafers W2, and an empty cassette C3 are mounted on a predetermined mounting plate 11 of the loading / unloading 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, under a predetermined reduced-pressure atmosphere, an oxygen gas as a processing gas is excited, turned into plasma, and ionized. The oxygen ions are applied to 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 S201).

  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 reformed in the surface reforming device 30, and the bonding surface concerned W1j is hydrophilized. Further, the bonding surface W1j of the upper wafer W1 is cleaned by the pure water (Step S202).

  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 W1 carried into the bonding apparatus 41 is transferred to the position adjusting mechanism 210 by the transfer mechanism 201 via the transition 200. Then, the horizontal direction of the upper wafer W1 is adjusted by the position adjusting mechanism 210 (Step S203).

  Thereafter, the upper wafer W1 is transferred from the position adjustment mechanism 210 to the holding arm 221 of the reversing mechanism 220. Subsequently, in the transfer area T1, the front and back surfaces of the upper wafer W1 are inverted by inverting the holding arm 221 (Step S204). That is, the bonding surface W1j of the upper wafer W1 is directed downward.

  Thereafter, the holding arm 221 of the reversing mechanism 220 rotates around the first driving unit 224 and moves below the upper chuck 230. Then, the upper wafer W1 is delivered from the reversing mechanism 220 to the upper chuck 230. The non-bonded surface W1n of the upper wafer W1 is suction-held by the upper chuck 230 (step S205).

  At this time, all the vacuum pumps 241a and 241b are operated, and the upper wafer W1 is suction-held in all the regions 230a and 230b of the upper chuck 230. The upper wafer W1 waits on the upper chuck 230 until the lower wafer W2 described later is transferred to the bonding apparatus 41.

  While the processing of steps S201 to S205 described above is being performed on the upper wafer W1, the processing 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 reforming device 30 by the transfer device 61, and the bonding surface W2j of the lower wafer W2 is reformed (Step S206). The modification of the bonding surface W2j of the lower wafer W2 in step S206 is the same as in step S201 described above.

  Thereafter, the lower wafer W2 is transferred by the transfer device 61 to the surface hydrophilizing device 40, where the bonding surface W2j of the lower wafer W2 is hydrophilized and the bonding surface W2j is cleaned (step S207). Note that the hydrophilicization and cleaning of the bonding surface W2j of the lower wafer W2 in step S207 are the same as in step S202 described above.

  After that, the lower wafer W2 is transferred to the bonding device 41 by the transfer device 61. The lower wafer W2 carried into the bonding device 41 is transferred to the position adjusting mechanism 210 by the transfer mechanism 201 via the transition 200. Then, the horizontal direction of the lower wafer W2 is adjusted by the position adjustment mechanism 210 (Step S208).

  Thereafter, the lower wafer W2 is transferred to the lower chuck 231 by the transfer mechanism 201, and is sucked and held by the lower chuck 231 (Step S209). At this time, as described with reference to FIG. 20, the control device 70 first activates the vacuum pump 261a to start suction holding of the lower wafer W2 by the first suction region 231a, and then controls the vacuum pump 261b. By operating, the suction holding of the lower wafer W2 by the second suction area 231b is started. The lower wafer W2 is suction-held on the lower chuck 231 so that the bonding surface W2j faces upward.

  Next, horizontal position adjustment of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 is performed (step S210).

  Next, the vertical positions of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are adjusted (step S211). This is performed, for example, by moving the lower chuck 231 vertically upward by the first lower chuck moving unit 290. Thereby, the distance between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 is adjusted to a predetermined distance, for example, 80 μm to 200 μm.

  Next, a bonding process of the upper wafer W1 and the lower wafer W2 is performed. Specifically, the operation of the vacuum pump 241a is stopped, and the evacuation of the upper wafer W1 from the suction pipe 240a in the region 230a is stopped. Thereafter, by lowering the push pins 251 of the push mechanism 250, the central portion of the upper wafer W1 is pushed down to contact the lower wafer W2. Then, the center of the upper wafer W1 and the center of the lower wafer W2 are pressed by the push pins 251 of the push mechanism 250 (step S212).

  Then, bonding starts between the pressed central portion of the upper wafer W1 and the central portion of the lower wafer W2. That is, 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 S201 and S206, respectively, first, van der Waals force (intermolecular force) is generated between the bonding surfaces W1j and W2j. Then, the joining surfaces W1j and W2j are joined. Furthermore, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been hydrophilized in steps S202 and S207, respectively, the hydrophilic groups between the bonding surfaces W1j and W2j are hydrogen-bonded, and the bonding surfaces W1j and W2j are formed. They are firmly joined.

  Thereafter, while the center of the upper wafer W1 and the center of the lower wafer W2 are pressed by the push pins 251, the operation of the vacuum pump 241b is stopped, and the upper wafer W1 is evacuated from the suction pipe 240b in the region 230b. To stop.

  Then, upper wafer W1 held in region 230b falls onto lower wafer W2. Accordingly, the bonding between the bonding surfaces W1j and W2j by the Van der Waals force and the hydrogen bond is sequentially expanded from the center of the upper wafer W1 and the lower wafer W2 toward the peripheral edge. Thus, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 abut on the entire surface, and the upper wafer W1 and the lower wafer W2 are bonded (step S213).

  Thereafter, the push pin 251 is raised to the upper chuck 230. Further, in the lower chuck 231, the evacuation of the lower wafer W 2 from the suction pipes 260 a and 260 b is stopped, and the suction and holding of the lower wafer W 2 by the lower chuck 231 is released. Thus, the joining process in the joining device 41 ends.

  As described above, the bonding device 41 according to the first embodiment includes the upper chuck 230 (an example of the first holding unit), the lower chuck 231 (an example of the second holding unit), and the pushing pin 251 (the pushing pin 251). Moving part) and a structure for canceling a difference in deformation amount due to anisotropy of Young's modulus. The upper chuck 230 sucks and holds the upper wafer W1 (an example of a first substrate) of the two substrates having anisotropic Young's modulus on the lower surface. The lower chuck 231 is provided below the upper chuck 230, and sucks and holds the lower wafer W2 (an example of a second substrate) of the two substrates on the upper surface 232. The push pins 251 press the central portion of the upper wafer W1 from above to contact the lower wafer W2. The structure for canceling the difference in the deformation amount due to the anisotropy of the Young's modulus is based on the anisotropic Young's modulus of the difference in the deformation amount between the upper wafer W1 and the lower wafer W2 caused by the pressing of the upper wafer W1 by the push pins 251. Cancels the difference in the amount of deformation due to sex.

  Therefore, according to the bonding apparatus 41 according to the first embodiment, it is possible to reduce the distortion generated in the overlapped wafer T that is the bonded substrate.

  In addition, the lower chuck 231 includes a pyramid-shaped upper surface 232 having sides 232a to 232d along the direction in which the Young's modulus is the highest or the lowest, as a structure for canceling the difference in the amount of deformation due to the anisotropy of the Young's modulus. .

  Thereby, when the lower wafer W2 is attracted to the upper surface 232 of the lower chuck 231, the deformation amount of the lower wafer W2 in the direction with the highest Young's modulus and the deformation amount in the direction with the lowest Young's modulus can be made different. it can.

  In addition, the bonding device 41 includes a control device 70 (an example of a second holding unit control unit) that controls the suction operation of the lower wafer W2 by the lower chuck 231. The lower chuck 231 is a first suction area 231a including the sides 232a to 232d in the suction area of the lower wafer W2, and a first suction area 231a other than the first suction area 231a in the suction area of the lower wafer W2. 2 adsorption area 231b. Then, the control device 70 starts the suction of the lower wafer W2 by the first suction area 231a and the suction of the lower wafer W2 by the second suction area 231b at different timings.

  Accordingly, the portion of the lower wafer W2 corresponding to the region where the suction is started later, of the first suction region 231a and the second suction region 231b, can be extended. For example, when the sides 232a to 232d of the upper surface 232 of the lower chuck 231 are formed along the direction having the lowest Young's modulus, the suction operation by the first suction region 231a is started first, so that the second operation is performed. The portion of the lower wafer W2 corresponding to the suction region 231b, that is, the portion along the direction having the highest Young's modulus can be extended. As a result, the lower wafer W2 can be stretched non-uniformly in the same manner as the upper wafer W1, so that the difference in the amount of deformation between the upper wafer W1 and the lower wafer W2 due to the anisotropy of the Young's modulus is canceled out, and the bonding is performed. It is possible to reduce distortion generated in the overlapped wafer T which is a substrate later.

  In addition, the upper surface 232 of the lower chuck may have concave or convex pyramid surfaces 233 and 234. Thus, the lower wafer W2 can be largely deformed while keeping the height of the protrusion of the upper surface 232 low.

(Second embodiment)
Next, configurations of the upper chuck and the lower chuck according to the second embodiment will be described with reference to FIGS. FIG. 25 is a schematic side view showing the configuration of the upper chuck and the lower chuck according to the second embodiment. FIG. 26 is a schematic plan view when the upper chuck according to the second embodiment is viewed from below. In the following description, the same parts as those already described are denoted by the same reference numerals as those already described, and redundant description will be omitted.

  As shown in FIG. 25, the joining device 41A according to the second embodiment includes an upper chuck 230A, a lower chuck 231A, and a pushing mechanism 250.

  The lower chuck 231A suction-holds the lower wafer W2 on the flat upper surface. The lower chuck 231A is provided with a suction pipe 260c for sucking and holding the lower wafer W2, and a vacuum pump 261c is connected to the suction pipe 260c.

  The upper chuck 230A suction-holds the upper wafer W1 on the lower surface which is a flat surface. Here, the configuration of the suction area formed on the lower surface of upper chuck 230A will be described with reference to FIG. FIG. 26 is a schematic plan view when the upper chuck 230A according to the second embodiment is viewed from below.

  As shown in FIG. 26, the upper chuck 230A includes a plurality of third suction areas 230c and 230d and a plurality of fourth suction areas 230e and 230f.

  The third suction regions 230c and 230d are arranged along the direction having the highest Young's modulus, that is, the direction having a 90 ° cycle. The third suction area 230c is arranged at a position closer to the center of the upper chuck 230A, and the third suction area 230d is arranged at a position farther from the center of the upper chuck 230A than the third suction area 230c. A suction pipe 240c is provided in the third suction area 230c (see FIG. 25), and a vacuum pump 241c is connected to the suction pipe 240c. Further, a suction pipe 240d is provided in the third suction area 230d, and a vacuum pump 241d is connected to the suction pipe 240d.

  The fourth suction regions 230e and 230f are arranged along the direction having the lowest Young's modulus, that is, the direction having a 45 ° cycle. The fourth suction area 230e is arranged at a position closer to the center of the upper chuck 230A, and the fourth suction area 230f is arranged at a position farther from the center of the upper chuck 230A than the fourth suction area 230e. A suction pipe 240e is provided in the fourth suction area 230e (see FIG. 25), and a vacuum pump 241e is connected to the suction pipe 240e. Further, a suction pipe 240f is provided in the fourth suction area 230f, and a vacuum pump 241f is connected to the suction pipe 240f.

  The third suction area 230c and the fourth suction area 230e are arranged concentrically, and the third suction area 230d and the fourth suction area 230f are arranged concentrically. The number of the third suction regions 230c and 230d and the number of the fourth suction regions 230e and 230f are not limited to those shown in the drawings.

  When pushing down the upper wafer W1 using the push pins 251, the controller 70 releases the suction of the lower wafer W2 by the third suction area 230 c, releases the suction of the lower wafer W2 by the third suction area 230 d, The release of the suction of the lower wafer W2 by the suction area 230e and the release of the suction of the lower wafer W2 by the fourth suction area 230f are started at different timings.

  Here, an example of the suction release processing of the upper wafer W1 by the control device 70 will be described with reference to FIGS. FIG. 27 is a flowchart illustrating an example of the suction release processing of the upper wafer W1. FIG. 28 is a diagram for explaining a difference in the amount of deformation between the upper wafer W1 and the lower wafer W2 according to the second embodiment. In the suction releasing process shown in FIG. 27, the upper wafer W1 is suctioned using all of the third suction regions 230c and 230d and the fourth suction regions 230e and 230f, and then the upper wafer W1 is pressed using the push pins 251. Execute during the push-down operation.

  As shown in FIG. 27, the control device 70 first releases the suction holding of the upper wafer W1 by the fourth suction region 230e (step S301), and then releases the suction holding of the upper wafer W1 by the third suction region 230c. (Step S302).

  As described above, the control device 70 is disposed along the direction in which the Young's modulus is the lowest among the third suction region 230c and the fourth suction region 230e concentrically arranged at a position near the center of the upper wafer W1. The suction operation of the fourth suction area 230e is first released. By releasing the suction operation of the fourth suction region 230e, the upper wafer W1 starts to expand in the direction having the lowest Young's modulus, that is, the direction in which the upper wafer W1 is unlikely to expand (the direction of the 45 ° cycle). At this time, since the suction operation of the third suction region 230c arranged along the direction with the highest Young's modulus has not been released yet, the upper wafer W1 extends in the direction with the highest Young's modulus, that is, the direction in which it is easy to expand. This is suppressed by the three suction regions 230c. As a result, as shown in FIG. 28, the non-uniformity of the elongation of the upper wafer W1 is reduced as compared with the case where the suction operation of the third suction region 230c and the suction operation of the fourth suction region 230e are simultaneously released. Then, it grows in a state close to a perfect circle.

  Subsequently, the control device 70 cancels the suction operation of the fourth suction area 230f arranged along the direction with the lowest Young's modulus among the third suction area 230d and the fourth suction area 230f arranged concentrically. After that (Step S303), the suction operation of the third suction area 230d is released (Step S304). Thereby, after the suction operation of the fourth suction region 230f is released, the upper wafer W1 is suppressed by the third suction region 230d from expanding in the direction having the highest Young's modulus, that is, in the direction in which the upper wafer W1 is easily stretched. The uniformity is reduced, and the film is stretched in a state close to a perfect circle.

  Here, an example in which the upper chuck 230A includes the third suction regions 230c and 230d and the fourth suction regions 230e and 230f has been described. However, the upper chuck 230A includes only the third suction regions 230c and 230d. A configuration may be provided. In such a case, after releasing the suction holding of the upper wafer W1 by the third suction area 230c, the control device 70 releases the suction holding of the upper wafer W1 by the third suction area 230d. This also makes it possible to suppress elongation in the direction having the highest Young's modulus, that is, in the direction in which elongation is easy.

  As described above, the bonding device 41A according to the second embodiment includes the control device 70 (an example of a first holding unit control unit) that controls the suction operation of the upper wafer W1 by the upper chuck 230A. In addition, the upper chuck 230A includes a plurality of third suction regions 230c and 230d arranged along the direction having the highest Young's modulus as a structure for canceling the difference in the deformation amount due to the anisotropy of the Young's modulus. Then, the control device 70 sequentially releases the suction of the upper wafer W1 by the plurality of third suction areas 230c and 230d from the center of the upper wafer W1 while the pressing pin 251 presses the upper wafer W1.

  In this way, the upper wafer W1 is extended (deformed) in the direction in which the elongation amount (deformation amount) is the largest, that is, in the direction in which the Young's modulus is the highest, so that the upper wafer W1 is evenly extended. By using such a material, the difference in the amount of deformation due to the anisotropy of the Young's modulus can be canceled out, whereby the distortion generated in the bonded substrate can be reduced.

  Further, the upper chuck 230A includes a plurality of fourth suction regions 230e and 230f arranged along the direction having the lowest Young's modulus. Then, while the upper wafer W1 is being pressed by the push pins 251, the control device 70 controls the fourth suction area 230e, 230f located at the position closest to the center of the upper wafer W1 among the plurality of fourth suction areas 230e and 230f. After releasing the suction of the upper wafer W1 by 230e, the suction of the upper wafer W1 by the third suction area 230c located closest to the center of the upper wafer W1 among the plurality of third suction areas 230c and 230d. Cancel.

  In this way, by delaying the suction release in the direction in which the deformation is easy, and the suction release in the direction in which the deformation is difficult, the upper wafer W1 can be more uniformly deformed.

(Third embodiment)
Next, the configuration of a joining device according to a third embodiment will be described with reference to FIG. FIG. 29 is a diagram illustrating an example of a configuration of a pressing member included in the joining device according to the third embodiment.

  As shown in FIG. 29, the joining device 41B according to the third embodiment includes a pressing member 270. The pressing member 270 is a substantially cross-shaped member in a plan view extending along the direction having the lowest Young's modulus, that is, a direction having a 45 ° cycle, and is formed of a flexible member such as rubber, for example.

  The pressing member 270 is arranged above the upper wafer W1, and is configured to be able to move up and down by a lifting mechanism (not shown). For example, a substantially cross-shaped groove may be formed on the upper surface of the upper chuck, and the pressing member 270 may be stored in the groove so as not to hinder the suction and holding of the upper wafer W1 by the upper chuck. At the center of the pressing member 270, a through hole 271 for inserting the pressing pin 251 is formed.

  The control device 70 lowers the pressing member 270 while pressing the upper wafer W1 by the pressing pin 251 and presses the upper wafer W1 from above in the direction having the lowest Young's modulus, that is, the direction of the 45 ° cycle. I do. This promotes the extension of the upper wafer W1 in the direction in which the Young's modulus is lowest, that is, the direction in which the upper wafer W1 is hardly extended, and the upper wafer W1 is extended in a perfect circular shape. The difference can be neglected.

  As described above, the bonding device 41B according to the third embodiment includes the pressing member 270 extending along the direction having the lowest Young's modulus and pressing the upper wafer W1 from above. Accordingly, the upper wafer W1 can be deformed as uniformly as possible by forcibly extending the portion of the upper wafer W1 in the direction in which the upper wafer W1 is not easily deformed by the pressing member 270. Therefore, according to the bonding apparatus 41B according to the third embodiment, the difference in the amount of deformation between the upper wafer W1 and the lower wafer W2 due to the anisotropy of the Young's modulus can be canceled out, and The distortion generated in the wafer T can be reduced.

  In each of the above-described embodiments, both the upper wafer W1 and the lower wafer W2 are single crystal silicon wafers having anisotropy in Young's modulus. However, any one of the upper wafer W1 and the lower wafer W2 is used. Only one may be a single crystal silicon wafer. Further, upper wafer W1 and / or lower wafer W2 are not limited to single-crystal silicon wafers, and may be other substrates having anisotropic Young's modulus.

  Further, the joining device may be configured to include the lower chuck 231 according to the first embodiment and the upper chuck 230A according to the second embodiment.

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

W1 Upper wafer (first substrate)
W2 Lower wafer (second substrate)
DESCRIPTION OF SYMBOLS 1 Joining system 41 Joining device 70 Controller 230 Upper chuck (1st holding part)
231 Lower chuck (second holding unit)
232 Upper surface 250 of lower chuck Pushing mechanism 251 Pushing pin (pushing member)
231a First suction area 231b Second suction area 230c, 230d Third suction area 230e, 230f Fourth suction area

Claims (8)

A first holding unit that sucks and holds the first substrate on the lower surface of the two substrates including the substrate having anisotropy in Young's modulus;
A second holding unit provided below the first holding unit, the second holding unit adsorbing and holding a second substrate of the two substrates on an upper surface;
A pushing portion that presses a central portion of the first substrate from above to contact the second substrate;
A structure for canceling a difference in the amount of deformation due to the anisotropy of the Young's modulus among the difference in the amount of deformation between the first substrate and the second substrate caused by the pressing of the first substrate by the pressing portion ;
A second holding unit control unit that controls a suction operation of the second substrate by the second holding unit ,
The second holding unit includes:
The structure includes the upper surface having a side along a direction in which the Young's modulus is the highest or the lowest, and a first suction region including the side of the suction region of the second substrate; A second adsorption area other than the first adsorption area,
The second holding unit control unit includes:
A bonding apparatus , wherein suction of the second substrate by the first suction region and suction of the second substrate by the second suction region are started at different timings . The upper surface is
The joining device according to claim 1 , wherein the joining device has a concave or convex pyramid surface. A first holding unit that sucks and holds the first substrate on the lower surface of the two substrates including the substrate having anisotropy in Young's modulus;
A second holding unit provided below the first holding unit, the second holding unit adsorbing and holding a second substrate of the two substrates on an upper surface;
A pushing portion that presses a central portion of the first substrate from above to contact the second substrate;
A structure for canceling a difference in the amount of deformation due to the anisotropy of the Young's modulus among the difference in the amount of deformation between the first substrate and the second substrate caused by the pressing of the first substrate by the pressing portion ;
A first holding unit control unit that controls a suction operation of the first substrate by the first holding unit ,
The first holding unit includes:
A plurality of third adsorption regions arranged along a direction having the highest Young's modulus
Comprising as the structure,
The first holding unit control unit includes:
The bonding apparatus according to claim 1, wherein, while the first substrate is being pressed by the pushing portion, the plurality of third suction regions sequentially release the suction of the first substrate from a central portion of the first substrate . The first holding unit includes:
A plurality of fourth suction regions arranged along a direction in which the Young's modulus is lowest,
The first holding unit control unit includes:
During the pressing of the first substrate by the pressing portion, of the plurality of fourth suction regions, the first substrate is positioned by the fourth suction region disposed at a position closest to the center of the first substrate. After releasing the suction, the suction of the first substrate by the third suction region arranged at a position closest to the center of the first substrate among the plurality of third suction regions is released. The bonding apparatus according to claim 3 , wherein A first holding unit that sucks and holds the first substrate on the lower surface of the two substrates including the substrate having anisotropy in Young's modulus;
A second holding unit provided below the first holding unit, the second holding unit adsorbing and holding a second substrate of the two substrates on an upper surface;
A pushing portion that presses a central portion of the first substrate from above to contact the second substrate;
A structure for canceling a difference in the amount of deformation caused by the anisotropy of the Young's modulus among the difference in the amount of deformation between the first substrate and the second substrate caused by the pressing of the first substrate by the pressing portion. ,
A bonding apparatus comprising: a pressing member that extends in a direction in which the Young's modulus is lowest and that presses the first substrate from above while being pressed by the pressing portion, as the structure . The substrate having anisotropic Young's modulus,
The bonding apparatus according to any one of claims 1 to 5 , wherein the bonding apparatus is a single crystal silicon wafer whose surface has a crystal direction of [100]. A surface modification device for modifying the surfaces of a first substrate and a second substrate, which are two substrates including a substrate having anisotropy in Young's modulus;
A surface hydrophilizing device for hydrophilizing the surfaces of the modified first substrate and the second substrate,
A bonding device for bonding the first substrate and the second substrate that have been hydrophilized by an intermolecular force;
The joining device,
A first holding unit that sucks and holds the first substrate on a lower surface;
A second holding unit provided below the first holding unit and holding the second substrate by suction on an upper surface;
A pushing portion that presses a central portion of the first substrate from above to contact the second substrate;
A structure for canceling a difference in the amount of deformation due to the anisotropy of the Young's modulus among the difference in the amount of deformation between the first substrate and the second substrate caused by the pressing of the first substrate by the pressing portion ;
A second holding unit control unit that controls a suction operation of the second substrate by the second holding unit ,
The second holding unit includes:
The structure includes the upper surface having a side along a direction in which the Young's modulus is the highest or the lowest, and a first suction region including the side of the suction region of the second substrate; A second adsorption area other than the first adsorption area,
The second holding unit control unit includes:
A bonding system , wherein the suction of the second substrate by the first suction region and the suction of the second substrate by the second suction region are started at different timings . A first holding step of sucking and holding the first substrate by using a first holding unit that sucks and holds the first substrate on a lower surface of the two substrates including a substrate having anisotropy in Young's modulus;
A second holding step that is provided below the first holding unit and that sucks and holds the second substrate, using a second holding unit that sucks and holds the second substrate on the upper surface of the two substrates;
A contact step of pressing a central portion of the first substrate from above to contact the second substrate;
The contact of the deformation amount of the difference between the first substrate and the second substrate resulting in the process, see contains a bucking step of canceling the difference in deformation amount due to the anisotropy of the Young's modulus,
The second holding unit includes:
A first suction area including the side and a suction area of the second substrate among the suction areas of the second substrate, the upper surface having sides along a direction in which the Young's modulus is highest or lowest. And a second suction area other than the first suction area,
The cancellation step includes:
The bonding method, wherein in the second holding step, the suction of the second substrate by the first suction region and the suction of the second substrate by the second suction region are started at different timings .

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