Bonding device and bonding method

Abstract

To provide a technique capable of appropriately correcting a height of an outer peripheral part of a substrate.SOLUTION: A joining device according to the disclosure includes: a first holding part; a second holding part; a pushing part; and a control part. The first holding part holds a first substrate from below. The second holding part is disposed above the first holding part and holds the second substrate from above. The pushing part is provided in the second holding part and pushes down a central part of a second substrate. The first holding part includes an outer suction part, an inner suction part, and a deformation part. The outer suction part sucks the outer peripheral part of the first substrate. The inner suction part sucks a portion inside the outer peripheral part of the first substrate. The deformation part deforms the outer suction part relative to the inner suction part. The control part acquires information on the height of the outer peripheral part of the first substrate from a reference plane, and controls the deformation part on the basis of the acquired information.SELECTED DRAWING: Figure 12

Description

[Technical Field]

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

[0002] BACKGROUND ART A bonding apparatus for bonding substrates such as semiconductor wafers together has been known in the past (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-095579 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can appropriately correct the height of the outer periphery of a substrate. [Means for solving the problem]

[0005] A bonding device according to one aspect of the present disclosure includes a first holding unit, a second holding unit, a pushing unit, and a control unit. The first holding unit holds the first substrate from below. The second holding unit is positioned higher than the first holding unit and holds the second substrate from above. The pushing unit is provided on the second holding unit and pushes down the center of the second substrate. The first holding unit has an outer suction unit, an inner suction unit, and a deformation unit. The outer suction unit sucks the outer periphery of the first substrate. The inner suction unit sucks a portion of the first substrate that is inside the outer periphery. The deformation unit deforms the outer suction unit relative to the inner suction unit. The control unit acquires information about the height of the outer periphery of the first substrate from a reference plane and controls the deformation unit based on the acquired information. [Effects of the Invention]

[0006] According to the present disclosure, the height of the outer periphery of the substrate can be appropriately corrected. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic plan view showing the configuration of a joining system according to a first embodiment. [Figure 2] FIG. 2 is a schematic side view showing the configuration of the joining system according to the first embodiment. [Figure 3] FIG. 3 is a schematic side view of the upper wafer and the lower wafer according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing the configuration of the joining device according to the first embodiment. [Figure 5] FIG. 5 is a schematic diagram showing the configuration of the joining device according to the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the configuration of the first holding section and the second holding section according to the first embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing the configuration of the first holding portion according to the first embodiment. [Figure 8] FIG. 8 is a schematic plan view showing the configuration of the first holding portion according to the first embodiment. [Figure 9] FIG. 9 is a schematic plan view showing the position of the suction surface when the outer suction portion according to the first embodiment is expanded. [Figure 10] FIG. 10 is a schematic cross-sectional view showing the configuration of the deformation section according to the first embodiment. [Figure 11] FIG. 11 is a flowchart showing the procedure of the process executed by the joint system according to the first embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of a specific procedure for the process shown in step S109. [Figure 13] FIG. 13 is a schematic cross-sectional view showing a configuration in which the outer suction portion is bulged. [Figure 14] FIG. 14 is a schematic plan view showing the configuration of a deformation section according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, a detailed description will be given of a bonding apparatus and a bonding method according to the present disclosure (hereinafter referred to as an "embodiment") with reference to the drawings. Note that the present disclosure is not limited to the embodiment. Furthermore, the embodiments can be appropriately combined as long as the processing content is not contradictory. Furthermore, the same components in the following embodiments are designated by the same reference numerals, and redundant description will be omitted.

[0009] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0010] In addition, for ease of understanding, the drawings referred to below may show an orthogonal coordinate system in which the X-axis, Y-axis, and Z-axis directions are defined as being orthogonal to each other, with the positive Z-axis direction being the vertically upward direction. Also, the direction of rotation around the vertical axis may be referred to as the θ direction.

[0011] When bonding substrates, the bonding device described in Patent Document 1 presses down the center of the first substrate held by a first holder to bring it into contact with the center of the second substrate held by a second holder. As a result, the centers of the two substrates are bonded together by intermolecular forces, and the bonded area where the two substrates are bonded expands from the center of the substrates toward the outer edges.

[0012] Here, the thickness of the outer periphery of the first or second substrate may become thinner than the thickness of the remaining portions due to a pre-bonding process, such as chemical mechanical polishing (CMP) or etching. In such a case, the height of the outer periphery of the first or second substrate becomes lower. As a result, the reference point of the outer periphery of the first substrate and the reference point of the outer periphery of the second substrate are misaligned. For example, if the outer periphery of the second substrate is thinner than the thickness of the remaining portions, after the first and second substrates are bonded, a radially inward strain component is generated in the first substrate relative to the second substrate. As a result, the bonding accuracy of the outer periphery may be reduced.

[0013] Therefore, a technology for appropriately correcting the height of the outer periphery of the substrate is desired.

[0014] (First embodiment) <Configuration of the joining system> First, the configuration of a bonding system 1 according to the first embodiment will be described with reference to Figs. 1 to 3. Fig. 1 is a schematic plan view showing the configuration of the bonding system 1 according to the first embodiment. Fig. 2 is a schematic side view showing the configuration of the bonding system 1 according to the first embodiment. Fig. 3 is a schematic side view of an upper wafer W1 and a lower wafer W2 according to the first embodiment.

[0015] The bonding system 1 shown in FIGS. 1 and 2 forms a laminated wafer T by bonding a first substrate W1 and a second substrate W2 together.

[0016] The first substrate W1 is a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer on which multiple electronic circuits are formed. The second substrate W2 is a bare wafer on which no electronic circuits are formed. The first substrate W1 and the second substrate W2 have approximately the same diameter.

[0017] An electronic circuit may be formed on the second substrate W2. The compound semiconductor wafer may be, for example, a wafer containing gallium arsenide, silicon carbide, gallium nitride, or indium phosphide, but is not limited to these.

[0018] Hereinafter, the first substrate W1 will be referred to as the "upper wafer W1," and the second substrate W2 will be referred to as the "lower wafer W2." That is, the upper wafer W1 is an example of the first substrate, and the lower wafer W2 is an example of the second substrate. Furthermore, the upper wafer W1 and the lower wafer W2 may be collectively referred to as "wafer W."

[0019] 3, of the surfaces of the upper wafer W1, the surface that is bonded to the lower wafer W2 will be referred to as a "bonding surface W1j," and the surface opposite the bonding surface W1j will be referred to as a "non-bonding surface W1n." Also, of the surfaces of the lower wafer W2, the surface that is bonded to the upper wafer W1 will be referred to as a "bonding surface W2j," and the surface opposite the bonding surface W2j will be referred to as a "non-bonding surface W2n."

[0020] 1, the bonding system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are arranged in the positive direction of the X-axis in this order. The loading / unloading station 2 and the processing station 3 are also integrally connected.

[0021] 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. Each mounting plate 11 is loaded with a cassette C1, C2, or C3, which stores a plurality of substrates (e.g., 25 substrates) in a horizontal position. For example, the cassette C1 stores an upper wafer W1, the cassette C2 stores a lower wafer W2, and the cassette C3 stores a laminated wafer T.

[0022] The transport area 20 is disposed adjacent to the mounting table 10 on the positive side of the X-axis. The transport area 20 is provided with a transport path 21 extending in the Y-axis direction and a transport device 22 movable along the transport path 21.

[0023] The transfer device 22 is movable not only in the Y-axis direction but also in the X-axis direction and rotatable around the Z-axis. The transfer device 22 transfers the upper wafer W1, the lower wafer W2, and the overlapped wafer T between the cassettes C1 to C3 placed on the mounting plate 11 and the third processing block G3 of the processing station 3, which will be described later.

[0024] The number of cassettes C1 to C3 placed on the placement plate 11 is not limited to that shown in the figure. In addition to the cassettes C1, C2, and C3, the placement plate 11 may also be placed with a cassette for recovering defective substrates.

[0025] Processing station 3 is provided with multiple processing blocks equipped with various devices, for example, three processing blocks G1, G2, and G3. For example, a first processing block G1 is provided on the front side of processing station 3 (the positive Y-axis side in FIG. 1), and a second processing block G2 is provided on the back side of processing station 3 (the negative Y-axis side in FIG. 1). Furthermore, a third processing block G3 is provided on the load / unload station 2 side of processing station 3 (the negative X-axis side in FIG. 1).

[0026] The first processing block G1 is provided with a surface modification device 30 that modifies the bonding surfaces W1j, W2j of the first substrate W1 and the second substrate W2. The surface modification device 30 breaks the SiO2 bonds on the bonding surfaces W1j, W2j of the first substrate W1 and the second substrate W2 to form single-bonded SiO, thereby modifying the bonding surfaces W1j, W2j so that they are more easily hydrophilized thereafter.

[0027] The first processing block G1 also includes a surface hydrophilization device 40. The surface hydrophilization device 40 hydrophilizes the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2 using, for example, pure water, and cleans the bonding surfaces W1j, W2j.

[0028] In the surface hydrophilization device 40, pure water is supplied onto the upper wafer W1 or the lower wafer W2 while the upper wafer W1 or the lower wafer W2 held by, for example, a spin chuck is rotated. As a result, the pure water supplied onto the upper wafer W1 or the lower wafer W2 spreads over the bonding surfaces W1j, W2j of the upper wafer W1 or the lower wafer W2, thereby making the bonding surfaces W1j, W2j hydrophilic.

[0029] Here, an example is shown in which the surface modification device 30 and the surface hydrophilization device 40 are arranged side by side, but the surface hydrophilization device 40 may be stacked above or below the surface modification device 30.

[0030] 2, the second processing block G2 is provided with a bonding device 41, a first temperature adjustment device 42, and a second temperature adjustment device 43. The bonding device 41 bonds the hydrophilized upper wafer W1 and lower wafer W2 together by intermolecular forces. The bonding device 41 will be described in detail later.

[0031] The first temperature adjustment device 42 adjusts the temperature distribution of the upper wafer W1 before fabricating the laminated wafer T. The second temperature adjustment device 43 adjusts the temperature distribution of the lower wafer W2 before fabricating the laminated wafer T. In this embodiment, the first temperature adjustment device 42 and the second temperature adjustment device 43 are provided separately from the bonding device 41, but they may also be provided as part of the bonding device 41.

[0032] In the third processing block G3, for example, a first position adjustment device 51, a second position adjustment device 52, and transition devices 53 and 54 are arranged in this order from top to bottom. Note that the locations of the devices in the third processing block G3 are not limited to those shown in FIG. 2. The first position adjustment device 51 adjusts the horizontal orientation of the upper wafer W1 and also turns the upper wafer W1 upside down so that the bonding surface W1j of the upper wafer W1 faces downward. The second position adjustment device 52 adjusts the horizontal orientation of the lower wafer W2. The transition device 53 temporarily places the upper wafer W1 thereon. In addition, the transition device 54 temporarily places the lower wafer W2 and the overlapped wafer T thereon.

[0033] 1, a transfer region 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 transfer device 61 is disposed in the transfer region 60. The transfer device 61 has a transfer arm that is movable, for example, vertically, horizontally, and around a vertical axis.

[0034] The transfer device 61 moves within the transfer region 60 and transfers the upper wafer W1, the lower wafer W2, and the overlapped wafer T to given devices within the first processing block G1, the second processing block G2, and the third processing block G3 adjacent to the transfer region 60.

[0035] The joint system 1 also includes a control device 70. The control device 70 controls the operation of the joint system 1. The control device 70 controls the operation of the joint system 1 based on signals from switches, various sensors, and the like.

[0036] The control device 70 includes a microcomputer and various circuits having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), input / output ports, etc. The control device 70 controls the operation of the bonding system 1 by, for example, reading and executing a program stored in a storage unit 72.

[0037] Next, an example of a bonding apparatus 41 according to the first embodiment will be described with reference to FIGS. 4 and 5. FIGS. 4 and 5 are schematic diagrams showing the configuration of the bonding apparatus 41 according to the first embodiment. As shown in FIG. 4, the bonding apparatus 41 has a processing vessel 210 whose interior can be sealed. A loading / unloading port 211 is formed on the side of the processing vessel 210 on the transfer region 60 side, and an opening / closing shutter 212 is provided at the loading / unloading port 211. The upper wafer W1, the lower wafer W2, and the overlapped wafer T are loaded and unloaded through the loading / unloading port 211.

[0038] 5, a first holding part 230 and a second holding part 231 are provided inside the processing vessel 210. The first holding part 230 holds the lower wafer W2 from below with the bonding surface W2j of the lower wafer W2 facing upward. The second holding part 231 is provided above the first holding part 230 and holds the upper wafer W1 from above with the bonding surface W1j of the upper wafer W1 facing downward. The first holding part 230 and the second holding part 231 are, for example, vacuum chucks.

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

[0040] As will be described later, the first moving section 291 moves the first holding section 230 in the horizontal direction (Y-axis direction). The first moving section 291 is also configured to be able to move the first holding section 230 vertically and to rotate it around a vertical axis.

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

[0042] The second moving part 296 is provided on the lower surface side of the second moving part 296 and is attached to a pair of rails 297 extending in the horizontal direction (X-axis direction). The second moving part 296 is configured to be movable along the rails 297. The pair of rails 297 is provided on a mounting part 298 provided on the bottom surface of the processing vessel 210.

[0043] The first moving unit 291 and the second moving unit 296 constitute a moving mechanism 290. The moving mechanism 290 moves the first holding unit 230 relative to the second holding unit 231. The moving mechanism 290 also moves the first holding unit 230 between a substrate transfer position and a bonding position.

[0044] The substrate transfer position is a position where the second holding unit 231 receives the upper wafer W1 from the transfer device 61, where the first holding unit 230 receives the lower wafer W2 from the transfer device 61, and where the first holding unit 230 transfers the overlapped wafer T to the transfer device 61. The substrate transfer position is a position where the overlapped wafer T produced in the nth (n is a natural number greater than or equal to 1) bonding is successively carried out, and the upper wafer W1 and lower wafer W2 to be bonded in the n+1th bonding are carried in. The substrate transfer position is, for example, a position shown in FIGS. 4 and 5.

[0045] The transfer device 61 enters a position directly below the second holding part 231 when transferring the upper wafer W1 to the second holding part 231. Furthermore, the transfer device 61 enters a position directly above the first holding part 230 when receiving the overlapped wafer T from the first holding part 230 and transferring the lower wafer W2 to the first holding part 230. To make it easier for the transfer device 61 to enter, the first holding part 230 and the second holding part 231 are shifted laterally, and the vertical distance between the first holding part 230 and the second holding part 231 is also large.

[0046] On the other hand, the bonding position is a position (opposing position) where the upper wafer W1 and the lower wafer W2 are faced to each other with a predetermined gap therebetween. The bonding position is, for example, the position shown in FIG. 6, which will be described later. At the bonding position, the gap between the upper wafer W1 and the lower wafer W2 in the vertical direction is narrower than at the substrate transfer position. Also, at the bonding position, unlike at the substrate transfer position, the upper wafer W1 and the lower wafer W2 overlap when viewed in the vertical direction.

[0047] The movement mechanism 290 moves the relative positions of the first holding unit 230 and the second holding unit 231 in the horizontal direction (both the X-axis direction and the Y-axis direction) and the vertical direction. In this embodiment, the movement mechanism 290 moves the first holding unit 230, but it may move either the first holding unit 230 or the second holding unit 231, or may move both. The movement mechanism 290 may also rotate the first holding unit 230 or the second holding unit 231 around the vertical axis.

[0048] Next, the configuration of the first holding portion 230 and the second holding portion 231 will be described with reference to Fig. 6. Fig. 6 is a schematic diagram showing the configuration of the first holding portion 230 and the second holding portion 231 according to the first embodiment.

[0049] 6, the first holding portion 230 is partitioned into a plurality of (for example, two) regions 230a and 230b along the radial direction of the first holding portion 230. These regions 230a and 230b are provided in this order from the center toward the outer edge of the first holding portion 230. The region 230a is formed in a perfect circular shape in a plan view, and the region 230b is formed in an annular shape in a plan view. The region 230b may have a plurality of arc-shaped zones (small regions) along the circumferential direction.

[0050] Suction pipes 260a and 260b are provided independently for the respective regions 230a and 230b. Different vacuum pumps 261a and 261b are connected to the respective suction pipes 260a and 260b. This allows the first holding part 230 to vacuum-suck the lower wafer W2 for each of the regions 230a and 230b.

[0051] The first holding part 230 is provided with a plurality of (for example, three) holding pins 265 that can be raised and lowered in the vertical direction. The lower wafer W2 is placed on the upper ends of the plurality of holding pins 265. The lower wafer W2 may be vacuum-sucked to the upper ends of the plurality of holding pins 265.

[0052] As the multiple holding pins 265 rise, they protrude from the suction surface of the first holding unit 230. In this state, the multiple holding pins 265 receive the lower wafer W2 from the transfer device 61. Thereafter, the multiple holding pins 265 descend, causing the lower wafer W2 to come into contact with the suction surface of the first holding unit 230. Next, the first holding unit 230 horizontally vacuum-sucks the lower wafer W2 in multiple regions of the suction surface.

[0053] 6, the second holding portion 231 is also partitioned into a plurality of (for example, three) regions 231a, 231b, and 231c along the radial direction of the second holding portion 231. These regions 231a, 231b, and 231c are provided in this order from the center toward the outer edge of the second holding portion 231. The region 231a is formed in a perfect circular shape in a plan view, and the regions 231b and 231c are formed in annular shapes in a plan view.

[0054] Suction pipes 240a, 240b, and 240c are independently provided in the respective regions 231a, 231b, and 231c. Different vacuum pumps 241a, 241b, and 241c are connected to the respective suction pipes 240a, 240b, and 240c. The second holding part 231 can vacuum-suck the upper wafer W1 in each of the regions 231a, 231b, and 231c.

[0055] The second holding part 231 is provided with a plurality of holding pins 245 that can be raised and lowered in the vertical direction. The plurality of holding pins 245 are connected to a vacuum pump 246, and vacuum-suck the upper wafer W1 by operating the vacuum pump 246. The upper wafer W1 is vacuum-sucked to the lower ends of the plurality of holding pins 245. Ring-shaped suction pads may be used instead of the plurality of holding pins 245.

[0056] The multiple holding pins 245 are lowered by a drive unit (not shown) to protrude from the suction surface of the second holding unit 231. In this state, the multiple holding pins 245 vacuum-suck the upper wafer W1 and receive it from the transfer device 61. Thereafter, the multiple holding pins 245 rise, and the upper wafer W1 comes into contact with the suction surface of the second holding unit 231. Next, the second holding unit 231 horizontally vacuum-sucks the upper wafer W1 in each of the regions 231a, 231b, and 231c by operating the vacuum pumps 241a, 241b, and 241c.

[0057] The second holding part 231 has a through-hole 243 at its center that passes through the second holding part 231 in the vertical direction. The pushing part 250 is inserted into the through-hole 243. The pushing part 250 pushes down the center of the upper wafer W1, which is disposed at an interval from the lower wafer W2, to bring the upper wafer W1 into contact with the lower wafer W2.

[0058] The pushing part 250 has a pushing pin 251 and an outer cylinder 252 that serves as a lifting guide for the pushing pin 251. The pushing pin 251 is inserted into the through-hole 243 by, for example, a drive part (not shown) having a built-in motor, protrudes from the suction surface of the second holding part 231, and pushes down the center of the upper wafer W1.

[0059] Next, the configuration of the first holding unit 230 according to the first embodiment will be described with reference to FIGS. 7 to 10. FIG. 7 is a schematic cross-sectional view showing the configuration of the first holding unit 230 according to the first embodiment. FIG. 8 is a schematic plan view showing the configuration of the first holding unit according to the first embodiment. FIG. 9 is a schematic plan view showing the position of the suction surface when the outer suction unit according to the first embodiment is expanded. FIG. 10 is a schematic cross-sectional view showing the configuration of the deformation unit according to the first embodiment. The first holding unit 230 has a function of deforming the height (shape) of the outer peripheral side of the suction surface 300 of the first holding unit 230 to correct the height of the outer peripheral portion of the lower wafer W2. Note that although the suction surface 300 of the first holding unit 230 is depicted flat in FIG. 7 and the following figures, the suction surface 300 may be configured to include a plurality of ribs extending radially and a plurality of ribs extending circumferentially.

[0060] Here, the thickness of the outer periphery of the upper wafer W1 or the lower wafer W2 may be thinner than the thickness of other portions due to a pre-bonding process, such as chemical mechanical polishing or etching. In such a case, the height of the outer periphery of the upper wafer W1 or the lower wafer W2 becomes lower. This may cause a misalignment between the reference point of the outer periphery of the upper wafer W1 and the reference point of the outer periphery of the lower wafer W2, resulting in a decrease in bonding accuracy. Therefore, the first holding unit 230 controls the height of the outer periphery side of the suction surface 300 of the first holding unit 230, thereby expanding or contracting the bonding surface W2j to match the height of the outer periphery of the lower wafer W2 and reducing the misalignment of the reference points.

[0061] Specifically, the first holding part 230 has an outer suction part 301 that suctions the outer periphery of the lower wafer W2, and an inner suction part 302 that suctions a portion of the lower wafer W2 that is more inward than the outer periphery. The inner suction part 302 is formed in a perfect circular shape in a plan view, and the outer suction part 301 is formed in an annular shape at a position adjacent to the outer side of the inner suction part 302.

[0062] The inner suction portion 302 has the above-mentioned regions 230a and 230b (see FIG. 6). The outer suction portion 301 overlaps a portion of the region 230b and is configured to be able to apply the suction pressure of the region 230b to the outer periphery of the lower wafer W2. For example, the outer suction portion 301 has a plurality of internal flow paths 305 extending radially outward from the suction pipe 260b and suction holes 306 that respectively communicate from each internal flow path 305 to the suction surface 300. As a result, the first holding portion 230 suctions the inner region including the center of the lower wafer W2 with the inner suction portion 302, while suctioning the outer periphery of the lower wafer W2 with the outer suction portion 301.

[0063] The first holding unit 230 has a function of deforming the outer suction portion 301 relative to the inner suction portion 302, both inside and outside the first holding unit 230. Specifically, the first holding unit 230 has a base member 310 that is mounted on the moving mechanism 290, and a holding member 320 that is stacked on the base member 310 and directly holds the lower wafer W2. The first holding unit 230 has a deformation portion 321 inside the holding member 320 that deforms the outer suction portion 301. The deformation portion 321 is provided on the outer periphery of the holding member 320.

[0064] In a vertical cross-sectional side view (see FIG. 7), the base member 310 has a convex shape having a base 311 fixed to the moving mechanism 290 (the moving stage of the moving mechanism 290) and a short protrusion 312 protruding vertically upward from the center of the base 311. The base member 310 supports the entire holding member 320 in the horizontal direction by fixing the surface (back surface) opposite the inner suction portion 302 of the holding member 320 to the upper end surface of the protrusion 312.

[0065] Therefore, the first holding unit 230 forms a clearance 313 between the upper surface of the base portion 311 of the base member 310 and the rear surface (e.g., the lower surface) of the outer suction portion 301 of the holding member 320, on the radially outer side of the protrusion 312, to provide a gap between the members. Here, the bonding device 41 has a mirror 314 located near the first holding unit 230 that reflects light from a displacement meter (not shown) that measures horizontal position during three-dimensional movement by the movement mechanism 290. The mirror 314 and the base member 310 are provided at a distance from each other on the movement stage of the movement mechanism 290. If the base member 310 were configured to deform in accordance with the deformation of the deformation portion 321 of the first holding unit 230, this could affect the reflection of the adjacent mirror 314.

[0066] Therefore, by not using the base member 310 to support the rear surface of the outer suction portion 301, the first holding portion 230 can prevent the influence of deformation of the outer suction portion 301 from being transmitted to the base member 310. In other words, even with a structure in which the outer suction portion 301 is deformed, the bonding device 41 can stabilize the reflection of the mirror 314 to improve measurement accuracy in the vicinity of the first holding portion 230, and it becomes possible to stably perform positioning of the first holding portion 230, etc.

[0067] The holding member 320 according to this embodiment has a deformation space 322 that constitutes the deformation portion 321 below the outer suction portion 301 (inside the outer suction portion 301 in the vertical direction). In a cross-sectional view along the vertical direction, the deformation space 322 is a space surrounded by a bottom wall 323, an top wall 324, an outer peripheral wall 325, and an inner peripheral wall 326 of the holding member 320. The deformation space 322 is formed in a rectangular shape with its long side extending horizontally, under the same pressure as the pressure outside the holding member 320. The bottom wall 323, the top wall 324, the outer peripheral wall 325, and the inner peripheral wall 326 may be integrally molded members, or some of the walls may be formed from different members. For example, the holding member 320 may have the lower wall 323 made of a material with a high elastic modulus (hard), and the upper wall 324, outer peripheral wall 325 and inner peripheral wall 326 made of a material with a lower elastic modulus (softer) than the lower wall 323.

[0068] The upper wall 324 that constitutes the deformation space 322 is provided with the above-mentioned internal flow paths 305 and suction holes 306. The thickness of the upper wall 324 (between the surface (e.g., the upper surface) of the outer suction portion 301 and the deformation space 322) is thinner than the thickness of the lower wall 323 (between the back surface (e.g., the lower surface) of the outer suction portion 301 and the deformation space 322). Therefore, when the internal pressure in the deformation space 322 fluctuates, the upper wall 324 deforms significantly, while the lower wall 323, the outer peripheral wall 325, and the inner peripheral wall 326 hardly deform. Therefore, the first holding portion 230 deforms the upper wall 324 in accordance with the fluctuations in the internal pressure of the deformation space 322, and the outer suction portion 301 can be deformed stably and reliably.

[0069] 8, the deformation space 322 is formed in a circular ring shape (annular shape) that circumscribes the inside of the holding member 320 that constitutes the adsorption surface 300. Therefore, the internal pressure of the deformation space 322 is applied uniformly in the circumferential direction of the holding member 320. Therefore, the first holding portion 230 can deform the outer adsorption portion 301 integrally and uniformly over the entire circumferential direction in accordance with fluctuations in the internal pressure of the deformation space 322.

[0070] For example, by increasing the internal pressure of the deformation space 322, the upper wall 324 bulges out over the entire circumferential direction of the holding member 320, as shown in Fig. 9. In Fig. 9, the white color indicates the vertical height (position) of the inner suction portion 302, which serves as a reference on the suction surface 300, and the darker the color, the higher the height of the suction surface 300. In this way, the first holding member 230 can deform the height of the outer suction portion 301 over the entire circumferential direction in accordance with the deformation of the deformation portion 321, thereby uniformly deforming the outer periphery of the lower wafer W2.

[0071] 7, in the bonding device 41, a fluid supply / discharge unit 330 that supplies and discharges a deformation fluid to the deformation space 322 is connected to a port on the side circumferential surface of the holding member 320. In this embodiment, the deformation fluid is air. Note that the deformation fluid is not limited to air, and an inert gas such as nitrogen (N2) or a liquid such as water or oil may also be used.

[0072] The fluid supply / discharge unit 330 is connected to a port of the holding member 320 and has a supply / discharge path 331 extending to the outside of the processing vessel 210. The fluid supply / discharge unit 330 includes, in order from the upstream side to the downstream side of the supply / discharge path 331, pumps (a pressure pump 332 and a pressure reduction pump 333), a regulator 334, a valve 335, and a pressure sensor 336.

[0073] The pressurizing pump 332 and the decompression pump 333 can, for example, branch off upstream of the regulator 334 and operate independently under the control of the control device 70. The pressurizing pump 332 supplies air to the holding member 320 to increase the internal pressure of the deformation space 322. The decompression pump 333 discharges air from the holding member 320 to reduce the internal pressure of the deformation space 322.

[0074] The regulator 334 is, for example, an electro-pneumatic regulator, and adjusts the pressure of the air flowing through the supply / discharge path 331 to a target pressure commanded by the control device 70. Note that the fluid supply / discharge unit 330 is not limited to using one regulator 334, and for example, a regulator 334 may be applied to each of the pressure pump 332 and the pressure reduction pump 333.

[0075] Valve 335 opens and closes the flow path in supply and discharge path 331 under the control of control device 70. For example, an air-operated valve (AOV) having the function of opening and closing supply and discharge path 331 and the function of opening to the atmosphere to allow air to flow in and out can be used as this valve 335. In this way, by opening valve 335 to the atmosphere when deformation of outer suction portion 301 is completed, it is possible to immediately restore deformation portion 321. Note that the number of valves 335 is not limited to one; for example, a valve 335 may be applied to each of pressure pump 332 and pressure pump 333.

[0076] Pressure sensor 336 detects the pressure of air supplied to or discharged from holding member 320 and transmits the detected information to control device 70. Based on the detected information from pressure sensor 336, control device 70 adjusts the amount of air supplied to deformation section 321 and closes valve 335 at an appropriate timing. With valve 335 closed, deformation space 322 is maintained at a predetermined internal pressure, allowing upper wall 324 to continue to deform.

[0077] Furthermore, the bonding device 41 includes a displacement sensor 340 (an example of a measurement unit) located vertically above the first holding unit 230 to detect the height of the outer periphery of the lower wafer W2. The displacement sensor 340 is installed, for example, above the outer suction unit 301 of the first holding unit 230, which is disposed at the substrate transfer position. The measurement method of the displacement sensor 340 is, for example, a confocal method, a spectral interference method, or a triangulation method. The light source of the displacement sensor 340 is an LED or a laser. The displacement sensor 340 is connected to the control device 70, measures the height of the outer periphery of the lower wafer W2 relative to the suction surface 300, and transmits the measured measurement information to the control device 70.

[0078] The control device 70 can operate the deformation unit 321 based on the measurement information measured by the displacement sensor 340. For example, the control device 70 stops the deformation of the deformation unit 321 when the height of the outer periphery of the lower wafer W2 is within a threshold range including the target height. Furthermore, when the height of the outer periphery of the lower wafer W2 is outside the threshold range including the target height, the control device 70 deforms the deformation unit 321 according to the amount of deviation from the target height. Although FIG. 7 illustrates one displacement sensor 340 installed at a position facing the outer suction unit 301, multiple displacement sensors 340 may be installed in the circumferential direction of the outer suction unit 301. The displacement sensor 340 may also be a first displacement meter that measures the thickness of the lower wafer W2, which will be described later. Instead of the displacement sensor 340, an imaging unit (not shown) that captures an image of the side surface of the lower wafer W2 may also be used. The height of the outer periphery of the lower wafer W2 may also be obtained from image data of the lower wafer W2 captured by the imaging unit.

[0079] Furthermore, when placing the lower wafer W2 on the suction surface 300 of the first holding unit 230, the bonding device 41 according to this embodiment deforms the lower wafer W2 by utilizing deformation of the widthwise intermediate portion of the outer suction portion 301 (deformation space 322). Here, the widthwise intermediate portion of the outer suction portion 301 refers to the vicinity of a widthwise intermediate position 301c of the outer suction portion 301, e.g., the central region when the outer suction portion 301 is divided into three equal parts in the width direction. Therefore, as shown in FIG. 10 , when holding the lower wafer W2 on the suction surface 300, the bonding device 41 positions the lower wafer W2 so that the outer edge of the lower wafer W2 is located near the widthwise intermediate position 301c of the outer suction portion 301. Note that in FIG. 10 , the widthwise intermediate position 301c of the outer suction portion 301 is indicated by a dashed line for convenience.

[0080] Since the outer edge of the lower wafer W2 is positioned near the widthwise intermediate position 301c of the outer suction portion 301, the formation range of the deformation space 322 is designed to a size corresponding to the dimensions of the lower wafer W2. For example, if the diameter of the lower wafer W2 is 300 mm, the diameter φI of the inner peripheral wall 326 of the deformation space 322 should be set in the range of 270 mm to 280 mm, and the diameter φO of the outer peripheral wall 325 of the deformation space 322 should be set in the range of 340 mm to 350 mm (see FIG. 8). In this embodiment, the diameter φI of the inner peripheral wall 326 is set to 276 mm, and the diameter φO of the outer peripheral wall 325 is set to 346 mm. Therefore, the width of the outer suction portion 301 (deformation space 322) is 70 mm, and the widthwise intermediate position 301c of the outer suction portion 301 is 35 mm. The diameter from the center of the first holding portion 230 to the widthwise intermediate position 301c of the outer suction portion 301 is 276 mm + 35 mm = 311 mm. The boundary between the outer suction portion 301 and the inner suction portion 302 may be defined by the inner circumferential wall 326. The outer suction portion 301 may be defined as the entire holding member 320 radially outward of the inner circumferential wall 326, or as the area where the deformation space 322 is formed (between the outer circumferential wall 325 and the inner circumferential wall 326). Alternatively, the boundary between the outer suction portion 301 and the inner suction portion 302 may be defined by the support portion (protrusion 312) and the non-support portion (clearance 313) of the base member 310 (see FIG. 7). For example, the ratio of the width of the outer suction portion 301 to the radius of the inner suction portion 302 is preferably set in the range of approximately 1 / 5 to 3 / 5.

[0081] By positioning the outer edge of the lower wafer W2 near the widthwise intermediate position 301c of the outer suction portion 301, the bonding device 41 can allow the deformation shape near the widthwise intermediate position 301c to affect the upper wafer W1 and the lower wafer W2 during deformation of the deformation portion 321. For example, if the thickness of the outer peripheral portion of the lower wafer W2 becomes thinner than the thickness of other portions and the height of the outer peripheral portion of the lower wafer W2 is smaller than a threshold range including the target height, the bonding device 41 performs an operation of expanding the deformation portion 321 (upper wall 324) of the deformation space 322 to bring the height of the outer peripheral portion of the bonding surface W2j within the threshold range (see FIG. 13). In this way, the bonding device 41 can accurately correct the height of the outer peripheral portion of the lower wafer W2 by utilizing the shape of the center side of the deformed outer suction portion 301. By correcting the height of the outer peripheral portion of the lower wafer W2, a radially inward distortion component is also applied to the upper wafer W1 during bonding, thereby canceling out each other's distortion components. As a result, a decrease in bonding accuracy can be suppressed.

[0082] <Specific operation of the joining system> Next, a specific operation of the joint system 1 according to the first embodiment will be described with reference to Fig. 11. Fig. 11 is a flowchart showing the procedure of processing executed by the joint system 1 according to the first embodiment. The various processing shown in Fig. 11 is executed based on the control of the control device 70.

[0083] 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 the mounting table 10 of the load / unload station 2. Thereafter, the upper wafer W1 in the cassette C1 is removed by the transfer device 22 and transferred to the transition device 53 arranged in the third processing block G3 of the processing station 3.

[0084] Next, the upper wafer W1 is transferred by the transfer device 61 to the surface modification device 30 in the first processing block G1. In the surface modification device 30, oxygen gas, which is a processing gas, is excited to form plasma and ionized in a predetermined reduced-pressure atmosphere. The oxygen ions are irradiated onto the bonding surface of the upper wafer W1, and the bonding surface is subjected to plasma processing. As a result, the bonding surface of the upper wafer W1 is modified (step S101).

[0085] Next, the upper wafer W1 is transferred by the transfer device 61 to the surface hydrophilization device 40 in the first processing block G1. In the surface hydrophilization device 40, pure water is supplied onto the upper wafer W1 while the upper wafer W1 held by the spin chuck is being rotated. This makes the bonding surface of the upper wafer W1 hydrophilic. The bonding surface of the upper wafer W1 is also cleaned with the pure water (step S102).

[0086] Next, the upper wafer W1 is transferred to the first position adjustment device 51 in the third processing block G3 by the transfer device 61. The first position adjustment device 51 adjusts the horizontal orientation of the upper wafer W1 and turns it over (step S103). As a result, the notch of the upper wafer W1 is oriented in a predetermined direction, and the bonding surface W1j of the upper wafer W1 faces downward.

[0087] Next, the upper wafer W1 is transferred by the transfer device 61 to the first temperature control device 42 in the second processing block G2. The temperature of the upper wafer W1 is controlled by the first temperature control device 42 (step S104). The temperature of the upper wafer W1 is controlled with the bonding surface W1j of the upper wafer W1 facing downward. Thereafter, the upper wafer W1 is transferred by the transfer device 61 to the bonding device 41.

[0088] The processing of the lower wafer W2 overlaps with the processing of steps S101 to S104 for the upper wafer W1. First, the transfer device 22 removes the lower wafer W2 from the cassette C2 and transfers it to the transition device 53 arranged in the third processing block G3.

[0089] Next, the lower wafer W2 is transferred by the transfer device 61 to the surface modification device 30, where the bonding surface W2j of the lower wafer W2 is modified (step S105). Thereafter, the lower wafer W2 is transferred by the transfer device 61 to the surface hydrophilization device 40, where the bonding surface W2j of the lower wafer W2 is hydrophilized and the bonding surface is cleaned (step S106).

[0090] Next, the lower wafer W2 is transferred by the transfer device 61 to the second position adjustment device 52. The horizontal orientation of the lower wafer W2 is adjusted by the second position adjustment device 52 (step S107). As a result, the notch of the lower wafer W2 is oriented in a predetermined direction.

[0091] Next, the lower wafer W2 is transferred by the transfer device 61 to the second temperature control device 43 in the second processing block G2. The temperature of the lower wafer W2 is controlled by the second temperature control device 43 (step S108). The temperature of the lower wafer W2 is controlled with the bonding surface W2j of the lower wafer W2 facing upward. Thereafter, the lower wafer W2 is transferred by the transfer device 61 to the bonding device 41.

[0092] Next, the upper wafer W1 and the lower wafer W2 are bonded together by the bonding device 41 to produce an overlapped wafer T (step S109). The process of step S109 will be described in detail later. Thereafter, the overlapped wafer T is transferred by the transfer device 61 to the transition device 54 in the third process block G3.

[0093] Thereafter, the overlapped wafer T is transferred by the transfer device 22 to the cassette C3 on the mounting table 10. This completes the series of processes.

[0094] Next, an example of a specific procedure for producing the overlapped wafer T in step S109 of Fig. 11 will be described with reference to Fig. 12 and Fig. 13. Fig. 12 is a flowchart showing an example of a specific procedure for the process shown in step S109. Fig. 13 is a schematic cross-sectional view showing a state in which the outer suction portion 301 is bulged.

[0095] First, the control unit 71 controls the first holding unit 230 to suck and hold from below the lower wafer W2 that has been carried into the bonding device 41. Similarly, the control unit 71 controls the second holding unit 231 to suck and hold from above the upper wafer W1 that has been carried into the bonding device 41 (step S201). In this case, the relative position between the first holding unit 230 and the second holding unit 231 is the substrate transfer position shown in FIG.

[0096] Next, the control unit 71 acquires information about the height of the outer periphery of the lower wafer W2 relative to the suction surface 300 from the displacement sensor 340 (step S202). For example, the control unit 71 controls the movement mechanism 290 (see FIGS. 4 and 5) to move the first holding unit 230 in the horizontal direction so that an arbitrary position on the outer periphery of the lower wafer W2 is located directly below the displacement sensor 340. Thereafter, the control unit 71 acquires height information at the arbitrary position from the displacement sensor 340. By repeatedly performing the process of moving the first holding unit 230 and the process of acquiring height information from the displacement sensor 340, the control unit 71 can acquire height information about the entire periphery of the lower wafer W2. The control unit 71 performs subsequent processes using, for example, an average value of the heights of the entire periphery of the lower wafer W2.

[0097] Next, the control unit 71 determines whether the height of the outer periphery of the lower wafer W2 relative to the suction surface 300 is within a threshold range including the target height (step S203). This target height is determined by measuring the thickness of the lower wafer W2 using a measuring device (not shown) before it is carried into the bonding system 1. For example, the thickness of the central part of the lower wafer W2 measured by the measuring device or the average value of thicknesses at multiple locations on the lower wafer W2 may be determined as the target height.

[0098] If the height of the outer periphery of the lower wafer W2 is outside the threshold range including the target height (No at step S203), the control unit 71 causes the deformation unit 321 to perform a deformation operation (step S204).

[0099] In the deformation operation, first, the control unit 71 releases the first holding unit 230 from suction of the lower wafer W2.

[0100] Next, the control unit 71 performs a pressurization process to increase the internal pressure of the deformation space 322 in accordance with the deviation between the height of the outer periphery of the lower wafer W2 and the target height. Specifically, the control unit 71 supplies air to the deformation space 322 using the fluid supply / discharge unit 330, causing the upper wall 324 to bulge (expand) vertically upward, as shown in FIG. 13 . At this time, the upper wall 324 curves in an arch shape with its apex at the widthwise intermediate position 301c. Therefore, after the deformation of the first holding unit 230, the lower wafer W2, whose outer edge is attracted radially inward of the widthwise intermediate position 301c of the outer suction unit 301, is held by the first holding unit 230 in a shape that is inclined vertically upward and radially outward.

[0101] The control unit 71 may obtain the amount of air to be supplied to the deformation space 322, for example, based on a table that corresponds the amount of air to be supplied to the height of the outer periphery of the lower wafer W2 and the deviation amount from the target height, which is pre-stored in the memory unit 72.

[0102] As a result, for example, if the thickness of the outer periphery becomes thinner than the thickness of other parts in a pre-bonding process, causing the height of the outer periphery of the lower wafer W2 to be low, the height of the outer periphery of the lower wafer W2 can be appropriately corrected when the lower wafer W2 is adsorbed, and the lower wafer W2 can be held.

[0103] During the deformation operation of the deformation unit 321 in step S204, the control unit 71 monitors the height of the outer periphery of the lower wafer W2 by repeating steps S202 and S203. Then, in step S203, if the height of the outer periphery of the lower wafer W2 is within a threshold range including the target height (step S203, Yes), the control unit 71 stops the deformation operation of the deformation unit 321, causes the first holding unit 230 to suction-hold the lower wafer W2 again, and proceeds to step S205. As described above, if the outer suction unit 301 is bulging, the lower wafer W2 is held in a deformed state with the outer periphery of the lower wafer W2. Note that if the height of the outer periphery of the lower wafer W2 is initially measured by the displacement sensor 340 and is within a threshold range including the target height, the process proceeds to step S205 without the deformation operation of the deformation unit 321.

[0104] Next, the control unit 71 controls the moving mechanism 290 to move the relative positions of the first holding unit 230 and the second holding unit 231 from the substrate transfer position to the bonding position shown in Fig. 6 (step S205). In step S205, the control unit 71 adjusts the horizontal positions of the upper wafer W1 and the lower wafer W2.

[0105] A plurality of predetermined reference points are formed on the bonding surface W1j of the upper wafer W1. A plurality of predetermined reference points are also formed on the bonding surface W2j of the lower wafer W2. These reference points may be, for example, predetermined patterns formed on the upper wafer W1 and the lower wafer W2. The number of reference points can be set arbitrarily.

[0106] The horizontal positions of the upper wafer W1 and the lower wafer W2 are adjusted using, for example, a first imaging unit and a second imaging unit (not shown). The first imaging unit captures an image of a reference point formed on the lower surface (bonding surface W1j) of the upper wafer W1, and the second imaging unit captures an image of a reference point formed on the upper surface (bonding surface W2j) of the lower wafer W2.

[0107] The image data captured by the first and second imaging units is output to the control unit 71. Based on this image data, the control unit 71 controls the movement mechanism 290 to move the first holding unit 230 in the horizontal direction so that the reference point of the upper wafer W1 and the reference point of the lower wafer W2 coincide with each other. The control unit 71 also rotates the first holding unit 230 around the vertical axis using the movement mechanism 290 so that the reference point of the upper wafer W1 and the reference point of the lower wafer W2 coincide with each other. In this way, the horizontal positions of the first holding unit 230 and the second holding unit 231 are adjusted, and the horizontal positions of the upper wafer W1 and the lower wafer W2 are adjusted.

[0108] Furthermore, in step S205, the control unit 71 adjusts the vertical positions of the upper wafer W1 and the lower wafer W2. Specifically, the control unit 71 controls the movement mechanism 290 to move the first holding unit 230 vertically upward. As a result, the gap G (see FIG. 6) between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 becomes a predetermined distance, for example, 80 μm to 200 μm. The gap G is adjusted using, for example, a first displacement meter and a second displacement meter (not shown). The first displacement meter measures the thickness of the lower wafer W2 held by the first holding unit 230. The second displacement meter measures the thickness of the upper wafer W1 held by the second holding unit 231. The thickness is measured, for example, when the movement mechanism 290 moves the second holding unit 231 in the horizontal direction.

[0109] The data measured by the first displacement meter and the second displacement meter are output to the control unit 71. The control unit 71 controls the movement mechanism 290 based on the data measured by the first displacement meter and the data measured by the second displacement meter, and adjusts the vertical position of the first holding unit 230 so that the gap G becomes a set value.

[0110] Next, the control unit 71 stops the operation of the vacuum pump 241a and releases the suction of the upper wafer W1 in the region 231a (see FIG. 5). Thereafter, the control unit 71 lowers the pushing pins 251 of the pushing unit 250 to push down the center of the upper wafer W1, thereby bringing the upper wafer W1 into contact with the lower wafer W2 (step S206). As a result, the centers of the upper wafer W1 and the lower wafer W2 are bonded together.

[0111] Because the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified, van der Waals forces (intermolecular forces) are generated between the bonding surfaces W1j and W2j, bonding the bonding surfaces W1j and W2j together. Furthermore, because the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been hydrophilized, hydrophilic groups (e.g., OH groups) form hydrogen bonds, firmly bonding the bonding surfaces W1j and W2j together.

[0112] Next, the control unit 71 stops the operation of the vacuum pump 241b to release the suction of the upper wafer W1 in the region 231b, and then stops the operation of the vacuum pump 241c to release the suction of the upper wafer W1 in the region 231c.

[0113] In this way, the vacuum suction of the upper wafer W1 is gradually released from the center toward the periphery of the upper wafer W1, and the upper wafer W1 gradually drops and contacts the lower wafer W2. Then, the bonding of the upper wafer W1 and the lower wafer W2 proceeds sequentially from the center toward the periphery (step S207). As a result, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into contact over their entire surfaces, the upper wafer W1 and the lower wafer W2 are bonded, and the laminated wafer T is obtained. Thereafter, the control unit 71 raises the pushing pin 251 to its original position.

[0114] After the laminated wafer T is produced, the control unit 71 controls the movement mechanism 290 to move the relative positions of the first holding unit 230 and the second holding unit 231 from the bonding position shown in Fig. 6 to the substrate transfer position shown in Fig. 4 and Fig. 5 (step S208). For example, the control unit 71 controls the movement mechanism 290 to first lower the first holding unit 230, thereby widening the vertical distance between the first holding unit 230 and the second holding unit 231. Next, the control unit 71 controls the movement mechanism 290 to move the first holding unit 230 laterally, thereby shifting the first holding unit 230 and the second holding unit 231 laterally.

[0115] Thereafter, the control unit 71 controls the transfer device 61 to transfer the overlapped wafer T out (step S209). Specifically, first, the control unit 71 releases the suction of the overlapped wafer T by the first holding unit 230. Next, the control unit 71 raises the multiple holding pins 265 and transfers the overlapped wafer T to the transfer device 61. Thereafter, the control unit 71 lowers the multiple holding pins 265 to their original positions.

[0116] As described above, the bonding apparatus 41 according to this embodiment can appropriately correct the height of the outer periphery of the lower wafer W2 by deforming the outer suction portion 301 relative to the inner suction portion 302 using the deformation portion 321. This makes it possible to bond the lower wafer W2 to the upper wafer W1 with the outer periphery of the bonding surface W2j of the lower wafer W2 being low, for example, by sufficiently correcting the height of the outer periphery. As a result, the bonding apparatus 41 can produce a laminated wafer T with reduced deviation between the reference point of the upper wafer W1 and the reference point of the lower wafer W2.

[0117] The control unit 71 also controls the first holding unit 230 to hold the lower wafer W2, then acquires information on the height of the outer periphery of the lower wafer W2 based on the suction surface 300 from the displacement sensor 340, controls the deformation unit 321 based on the acquired information to deform the outer suction unit 301, and then controls the outer suction unit 301 and the inner suction unit 302 to suction the lower wafer W2.

[0118] In this way, the control unit 71 performs the deformation process of the first holding unit 230 using the deformation unit 321 after temporarily releasing the suction of the lower wafer W2, and then adsorbs the lower wafer W2 again, so that pressure is less likely to be applied to the lower wafer W2 from the first holding unit 230 during the deformation process. Note that the control unit 71 may also raise the multiple holding pins 265 after releasing the suction of the lower wafer W2, and perform the deformation process in a state where the lower wafer W2 and the first holding unit 230 are not in contact with each other.

[0119] While the example of measuring the height of the outer periphery of the lower wafer W2 has been described here, the height of the outer periphery of the upper wafer W1 may also be measured. For example, the bonding apparatus 41 may further include a displacement sensor (not shown) that measures the height of the outer periphery of the upper wafer W1. In this case, in step S202 of FIG. 12 , the control unit 71 may acquire information about the height of the outer periphery of the upper wafer W1 from the displacement sensor, and in step S203, determine whether the sum of the heights of the outer peripheries of the lower wafer W2 and the upper wafer W1 is within a threshold range including the target total height. That is, the control unit 71 may control the deformation unit 321 based on information about the heights of the outer peripheries of the upper wafer W1 and the lower wafer W2. Alternatively, the deformation unit 321 may be controlled using only information about the height of the outer periphery of the upper wafer W1.

[0120] Furthermore, in addition to the bonding process, a correction process may be performed in the subsequent photolithography process according to the amount of deviation between the height of the outer periphery of the lower wafer W2 and the target height.

[0121] (Second embodiment) FIG. 14 is a schematic plan view showing the configuration of the deformation unit 321 according to the second embodiment. As shown in FIG. 14, the deformation unit 321, which deforms the outer suction unit 301, may have multiple deformation spaces 322A separated along the circumferential direction of the second holding unit 231, and may supply or exhaust air to each of the multiple deformation spaces 322A. This allows the first holding unit 230 to individually adjust the amount of circumferential deformation of the outer suction unit 301 based on the height measured at multiple locations on the outer periphery of the lower wafer W2. That is, if the height is measured at multiple locations on the outer periphery of the lower wafer W2 in step S202 of FIG. 12, the control unit 71 supplies air to the deformation spaces 322A corresponding to the measured locations in subsequent steps S203 and S204, depending on the deviation between the height of the measured locations and the target height. That is, the bonding device 41 can appropriately perform correction based on the relative difference in height of the outer periphery of the lower wafer W2. 16 shows a configuration in which the lower wafer W2 is divided into eight deformation spaces 322A, the number of divisions and the volume of each space can be freely designed. Here, an example in which the height of the lower wafer W2 is measured at multiple locations on the outer periphery thereof has been described, but the method for measuring the height of the outer periphery of the lower wafer W2 is not limited to this. For example, the height of the outer periphery of the lower wafer W2 may be measured while rotating the lower wafer W2 by 360°.

[0122] (Third embodiment) In the first embodiment, the case where the height of the outer periphery of the lower wafer W2 is measured inside the bonding apparatus 41 has been described. However, this is not limiting and the height of the outer periphery of the lower wafer W2 may be measured outside the bonding apparatus 41. For example, the height of the outer periphery of the lower wafer W2 may be measured by a measuring device (not shown) inside the bonding system 1. The measuring device outputs information about the measured height of the outer periphery of the lower wafer W2 to the control device 70, and the control device 70 controls the deforming unit 321 based on the acquired information. Alternatively, the height of the outer periphery of the lower wafer W2 may be measured by a measuring device (not shown) outside the bonding system 1. The measuring device outputs information about the measured height of the outer periphery of the lower wafer W2 to the control device 70 via a network, and the control device 70 controls the deforming unit 321 based on the acquired information.

[0123] In this case, the process of step S202 in FIG. 12 can be omitted, and the processing throughput can be improved.

[0124] (Fourth embodiment) In the first embodiment, in the deformation operation by the deformation unit 321, the control unit 71 first releases the adsorption of the lower wafer W2, then performs the deformation process of the first holding unit 230 by the deformation unit 321, and then adsorbs the lower wafer W2 again. However, this is not limited to this, and the deformation process by the first holding unit 230 may be performed while the lower wafer W2 is still adsorbed.

[0125] Specifically, the control unit 71 may control the first holding unit 230 to hold the lower wafer W2, then control the outer suction unit 301 and the inner suction unit 302 to suction the lower wafer W2, and then obtain information about the height of the outer periphery of the lower wafer W2 relative to the suction surface 300 from the displacement sensor 340, and control the deformation unit 321 based on the obtained information to deform the outer suction unit 301. That is, in step 204 of FIG. 12 , the control unit 71 may only control the deformation unit 321 without performing the processes of releasing the suction and re-sucking the lower wafer W2.

[0126] This allows the time required for the bonding process to be shortened compared to when the lower wafer W2 is released from suction and then re-sucked.

[0127] The disclosed embodiments should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0128] The present disclosure can be configured as follows. (1) a first holding portion that holds the first substrate from below; a second holding portion disposed above the first holding portion and holding a second substrate from above; a pressing portion provided on the second holding portion and configured to press down a central portion of the second substrate; Control unit and Equipped with The first holding portion is an outer suction portion that suctions an outer periphery of the first substrate; an inner suction portion that suctions a portion of the first substrate that is inner than the outer periphery; a deformation portion that deforms the outer suction portion relative to the inner suction portion; and The control unit acquires information about the height of the outer periphery of the first substrate from a reference surface, and controls the deformation unit based on the acquired information. (2) The bonding apparatus described in (1), wherein the control unit controls the deformation unit according to the amount of deviation from the target height when the height of the outer periphery of the first substrate from the reference surface is outside a threshold range including the target height. (3) the deformation portion has a deformation space inside the first holding portion located at the outer suction portion, The bonding device described in (2), wherein the control unit controls the deformation unit to supply fluid to the deformation space to cause the outer suction portion to bulge relative to the inner suction portion when the height of the outer periphery of the first substrate from the reference surface is outside a threshold range including the target height. (4) a measuring unit for measuring a height of the outer periphery of the first substrate relative to an adsorption surface of the outer adsorption unit, The bonding device according to any one of (1) to (3), wherein the control unit controls the deformation unit based on information acquired from the measurement unit. (5) The bonding device according to any one of (1) to (4), wherein the outer edge of the first substrate is disposed at a widthwise intermediate portion of the outer suction portion. (6) 5. The bonding device of claim 4, wherein the control unit controls the first holding unit to hold the first substrate, then acquires information about the height of the outer periphery of the first substrate relative to the suction surface of the outer suction unit from the measurement unit, controls the deformation unit to deform the outer suction unit based on the acquired information, and then controls the outer suction unit and the inner suction unit to suction the first substrate. (7) 5. The bonding device of claim 4, wherein the control unit controls the first holding unit to hold the first substrate, then controls the outer suction unit and the inner suction unit to suction the first substrate, then obtains information about the height of the outer periphery of the first substrate relative to the suction surface of the outer suction unit from the measurement unit, and controls the deformation unit to deform the outer suction unit based on the obtained information. (8) a step of holding the first substrate from below using a first holding part that holds the first substrate from below; holding the second substrate from above using a second holding unit that is disposed above the first holding unit and holds the second substrate from above; acquiring information about the height of the outer periphery of the first substrate from a reference surface; a step of deforming the outer suction portion, which suctions the outer suction portion, by using a deformation portion that deforms the outer suction portion, which suctions the outer suction portion, based on the acquired information, relative to an inner suction portion that suctions a portion of the first substrate that is more inward than the outer periphery; adsorbing the first substrate using the outer adsorption portion and the inner adsorption portion; a step of pressing down a central portion of the second substrate held by the second holding unit using a pressing unit that is provided on the second holding unit and presses down the central portion of the second substrate; A bonding method comprising: [Explanation of symbols]

[0129] 1. Joint System 41 Joining equipment 70 Control device 71 Control Unit 72 Memory section 230 1st holding part 231 Second holding part 250 Pushing part 301 Outside suction part 302 Inner suction part 321 Deformed part W1 upper wafer W2 lower wafer

Claims

1. a first holding portion that holds the first substrate from below; a second holding portion disposed above the first holding portion and configured to hold a second substrate from above; a pressing portion provided on the second holding portion and configured to press down a central portion of the second substrate; Control unit and Equipped with The first holding portion is an outer suction portion that suctions an outer periphery of the first substrate; an inner suction portion that suctions a portion of the first substrate that is inner than the outer periphery; a deformation portion that deforms the outer suction portion relative to the inner suction portion; and The control unit acquires information about the height of the outer periphery of the first substrate from a reference surface, and controls the deformation unit based on the acquired information.

2. The bonding device according to claim 1, wherein the control unit controls the deformation unit according to the amount of deviation from the target height when the height of the outer periphery of the first substrate from the reference surface is outside a threshold range including the target height.

3. the deformation portion has a deformation space inside the first holding portion located at the outer suction portion, The bonding device according to claim 2, wherein the control unit controls the deformation unit to supply fluid to the deformation space to cause the outer suction portion to bulge relative to the inner suction portion when the height of the outer periphery of the first substrate from the reference surface is outside a threshold range including a target height.

4. a measuring unit for measuring a height of the outer periphery of the first substrate relative to an adsorption surface of the outer adsorption unit, The joining device according to claim 1 , wherein the control unit controls the deformation unit based on information acquired from the measurement unit.

5. The bonding device according to claim 1 , wherein an outer edge of the first substrate is located at a widthwise intermediate portion of the outer suction portion.

6. 5. The bonding device according to claim 4, wherein the control unit controls the first holding unit to hold the first substrate, then acquires information about the height of the outer periphery of the first substrate relative to the suction surface of the outer suction unit from the measurement unit, controls the deformation unit to deform the outer suction unit based on the acquired information, and then controls the outer suction unit and the inner suction unit to suction the first substrate.

7. 5. The bonding device according to claim 4, wherein the control unit controls the first holding unit to hold the first substrate, then controls the outer suction unit and the inner suction unit to suction the first substrate, then acquires information about the height of the outer periphery of the first substrate relative to the suction surface of the outer suction unit from the measurement unit, and controls the deformation unit based on the acquired information to deform the outer suction unit.

8. a step of holding the first substrate from below using a first holding part that holds the first substrate from below; holding the second substrate from above using a second holding unit that is disposed above the first holding unit and holds the second substrate from above; acquiring information about the height of the outer periphery of the first substrate from a reference surface; a step of deforming the outer suction portion by using a deformation portion that deforms the outer suction portion that adsorbs the outer periphery of the first substrate relative to an inner suction portion that adsorbs a portion of the first substrate that is more inward than the outer periphery, based on the acquired information; adsorbing the first substrate using the outer adsorption portion and the inner adsorption portion; a step of pressing down a central portion of the second substrate held by the second holding portion using a pressing portion provided on the second holding portion and pressing down the central portion of the second substrate; A bonding method comprising:

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