JP6616181B2 - Joining device - Google Patents

Description

The disclosed embodiments relates to joining equipment.

  Conventionally, in order to meet the demand for higher integration of semiconductor devices, it has been proposed to use a three-dimensional integration technique for three-dimensionally stacking semiconductor devices. As an apparatus using this three-dimensional integration technique, for example, a bonding apparatus that bonds substrates such as a semiconductor wafer (hereinafter referred to as “wafer”) is known.

  For example, in Patent Document 1, of two wafers arranged opposite to each other in the vertical direction, the central portion of the upper wafer is pressed with a push pin so that the central portion is brought into contact with the lower wafer. A technique is disclosed in which the spacers supporting the wafer are retracted, the entire upper wafer is brought into contact with the entire lower wafer, and the substrates are bonded to each other.

JP 2004-207436 A

  However, the above-described conventional technology has room for further improvement in improving the bonding quality of the substrates.

  Specifically, in the case of using the above-described conventional technology, the upper wafer is extended more than the lower wafer by pressing only the upper wafer with the push pin, and there is a risk that positional displacement occurs in the bonding between the substrates. was there.

  In this regard, for example, there is a technique in which the lower wafer is preheated and thermally expanded to cancel out the elongation of the upper wafer. However, when such a technique is used, distortion is likely to occur due to a slight temperature distribution difference in the wafer surface. There is a problem.

One aspect of the embodiment aims to provide a bonding equipment which can improve the bonding quality of the substrate.

A joining apparatus according to an aspect of the embodiment includes a first holding unit, a second holding unit, a deformation stage, and a control unit. The first holding unit holds the first substrate on the lower surface side. The second holding unit is provided below the first holding unit, and holds the second substrate facing the first substrate on the upper surface side. The deformation stage is disposed as the lower surface of the first holding unit and the upper surface of the second holding unit, and is formed so that the back side is substantially spherical, and can be convexly deformed while holding the first substrate and the second substrate, respectively. Is provided. The control unit causes the first holding unit and the second holding unit to approach each other in a state where the deformation stage is convexly deformed, and then causes the central parts of the first substrate and the second substrate to contact each other, and then the convex deformation of the deformation stage. The first substrate and the second substrate are joined by further approaching the first holding unit and the second holding unit while releasing the.

  According to one aspect of the embodiment, the bonding quality of the substrates can be improved.

FIG. 1 is a schematic plan view showing a configuration of a joining system according to an embodiment. FIG. 2 is a schematic side view illustrating the configuration of the bonding system according to the embodiment. FIG. 3 is a schematic side view of the upper wafer and the lower wafer. FIG. 4 is a schematic plan view showing the configuration of the bonding apparatus. FIG. 5 is a schematic side view showing the configuration of the bonding apparatus. FIG. 6 is a schematic side view showing the configuration of the position adjusting mechanism. FIG. 7 is a schematic plan view showing the configuration of the reversing mechanism. FIG. 8 is a schematic side view (part 1) illustrating the configuration of the reversing mechanism. FIG. 9 is a schematic side view (part 2) illustrating the configuration of the reversing mechanism. FIG. 10 is a schematic side view illustrating the configuration of the holding arm and the holding member. FIG. 11 is a schematic side view showing the internal configuration of the bonding apparatus. FIG. 12A is a perspective view showing a configuration of the lower chuck. FIG. 12B is a modified explanatory view of the lower chuck. FIG. 12C is a schematic cross-sectional view showing the configuration of the upper chuck and the lower chuck. FIG. 12D is a schematic plan view when the lower chuck is viewed from above. FIG. 13 is a flowchart illustrating a part of a processing procedure of processing executed by the joining system. FIG. 14A is an operation explanatory diagram (part 1) of the bonding apparatus. FIG. 14B is an operation explanatory diagram (No. 2) of the bonding apparatus. FIG. 14C is an operation explanatory diagram (part 3) of the bonding apparatus. FIG. 14D is an operation explanatory diagram (part 4) of the bonding apparatus. FIG. 14E is an operation explanatory diagram (No. 5) of the bonding apparatus. FIG. 14F is an operation explanatory diagram (No. 6) of the bonding apparatus. FIG. 14G is an explanatory diagram of the operation of the bonding apparatus (part 7). FIG. 14H is an explanatory diagram of the operation of the bonding apparatus (No. 8). FIG. 14I is an operation explanatory diagram (No. 9) of the bonding apparatus. FIG. 15A is a schematic cross-sectional view showing a deformation structure of a deformation stage. FIG. 15B is a schematic plan view showing a deformation structure of the deformation stage. FIG. 15C is an explanatory diagram (part 1) of the Z displacement and the X displacement of the deformation stage. FIG. 15D is an explanatory diagram (part 2) of the Z displacement and the X displacement of the deformation stage. FIG. 16A is a schematic cross-sectional view showing another deformation structure of the deformation stage. FIG. 16B is a schematic plan view showing another deformation structure of the deformation stage.

Hereinafter, with reference to the accompanying drawings, an embodiment of the joining equipment disclosed in the present application in detail. In addition, this invention is not limited by embodiment shown below.

  In each drawing referred to below, in order to make the explanation easy to understand, an orthogonal coordinate system in which a vertically upward direction is a positive direction of the Z-axis may be shown.

<1. Structure of joining system>
First, the structure of the joining system which concerns on this embodiment is demonstrated with reference to FIGS. 1-3. FIG. 1 is a schematic plan view showing a configuration of a joining system according to the present embodiment, and FIG. 2 is a schematic side view thereof. FIG. 3 is a schematic side view of the upper wafer and the lower wafer.

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

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

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

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

  The carry-in / out station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 includes a plurality of mounting plates 11. On each mounting plate 11, cassettes C1, C2, and C3 for storing a plurality of (for example, 25) substrates in a horizontal state are mounted. For example, the cassette C1 is a cassette that accommodates the upper wafer W1, the cassette C2 is a cassette that accommodates the lower wafer W2, and the cassette C3 is a cassette that accommodates the superposed wafer T.

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

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

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

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

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

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

  In the third processing block G3, as shown in FIG. 2, transition (TRS) devices 50 and 51 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T are provided in two stages in order from the bottom.

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

  In addition, as illustrated in FIG. 1, the bonding system 1 includes a control device 70. The control device 70 controls the operation of the bonding system 1. The control device 70 is a computer, for example, and includes a control unit and a storage unit (not shown). The storage unit stores a program for controlling various processes such as a bonding process. The control unit controls the operation of the bonding system 1 by reading and executing the program stored in the storage unit.

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

<2. Structure of joining device>
Next, the structure of the joining apparatus 41 is demonstrated with reference to FIGS. FIG. 4 is a schematic plan view showing the configuration of the bonding apparatus 41, and FIG. 5 is a schematic side view thereof. FIG. 6 is a schematic side view showing the configuration of the position adjusting mechanism 210. FIG. 7 is a schematic plan view showing the configuration of the reversing mechanism 220, and FIGS. 8 and 9 are schematic side views (No. 1) and (No. 2). FIG. 10 is a schematic side view showing the configuration of the holding arm 221 and the holding member 222, and FIG. 11 is a schematic side view showing the internal configuration of the joining device 41.

  As shown in FIG. 4, the joining apparatus 41 includes a processing container 190 that can seal the inside. A loading / unloading port 191 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is formed on the side surface of the processing container 190 on the transfer area 60 side, and an opening / closing shutter 192 is provided at the loading / unloading port 191.

  The inside of the processing container 190 is divided into a transport area T1 and a processing area T2 by an inner wall 193. The loading / unloading port 191 described above is formed on the side surface of the processing container 190 in the transfer region T1. In addition, a carry-in / out 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 placing the upper wafer W1, the lower wafer W2, and the superposed wafer T is provided on the negative side of the transfer region T1 in the Y axis direction. The transition 200 is formed, for example, in two stages, and any two of the upper wafer W1, the lower wafer W2, and the superposed wafer T can be placed simultaneously.

  A transport mechanism 201 is provided in the transport region T1. The transport mechanism 201 has, for example, a transport arm that can move around the vertical direction, the horizontal direction, and the vertical axis. Then, the transport mechanism 201 transports the upper wafer W1, the lower wafer W2, and the overlapped wafer T within the transport region T1 or between the transport region T1 and the processing region T2.

  A position adjustment mechanism 210 that adjusts the horizontal orientation of the upper wafer W1 and the lower wafer W2 is provided on the Y axis positive direction side of the transfer region T1. As shown in FIG. 6, the position adjustment mechanism 210 detects the positions of the base 211, the holding unit 212 that holds and rotates the upper wafer W1 and the lower wafer W2, and the notch portions of the upper wafer W1 and the lower wafer W2. And a detecting unit 213 for performing

  In the position adjustment mechanism 210, the position of the notch portions of the upper wafer W1 and the lower wafer W2 is detected by the detection unit 213 while rotating the upper wafer W1 and the lower wafer W2 held by the holding unit 212. The horizontal direction of the upper wafer W1 and the lower wafer W2 is adjusted by adjusting the position of the portion.

  In addition, a reversing mechanism 220 that reverses the front and back surfaces of the upper wafer W1 is provided in the transfer region 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 holding members 222 for holding the upper wafer W1, for example, at four locations. As shown in FIG. 10, the holding member 222 is configured to be movable in the horizontal direction with respect to the holding arm 221. 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 sandwich and hold the upper wafer W1.

  As shown in FIGS. 7 to 9, the holding arm 221 is supported by a first drive unit 224 provided with, for example, a motor. The holding arm 221 can be rotated around the horizontal axis by the first driving unit 224. The holding arm 221 is rotatable about the first driving 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 unit 224 is movable in the vertical direction along the support pillar 226 extending in the vertical direction by the second drive unit 225.

  Thus, the upper wafer W1 held by the holding member 222 can be rotated around the horizontal axis by the first drive unit 224 and the second drive unit 225 and can move in the vertical direction and the horizontal direction. it can. Further, the upper wafer W <b> 1 held by the holding member 222 can rotate around the first driving unit 224 and move from the position adjusting mechanism 210 to the upper chuck 230 described later.

  Further, as shown in FIG. 5, 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. The lower chuck 231 is provided below the upper chuck 230 and sucks and holds the lower wafer W2 from below.

  Further, as indicated by broken lines, the upper chuck 230 and the lower chuck 231 can be convexly deformed while holding the upper wafer W1 and the lower wafer W2, respectively. That is, the upper wafer W1 and the lower wafer W2 are also deformed on the holding surface according to the convex deformation of the holding surface. Hereinafter, such a holding surface is referred to as a “deformation stage”. A specific configuration of the deformation stage will be described later with reference to FIG.

  As shown in FIG. 5, the upper chuck 230 is supported by a support member 280 provided on the ceiling surface of the processing container 190. The support member 280 is provided with an upper imaging unit 281 (see FIG. 11) that images the bonding surface W2j of the lower wafer W2 held by the lower chuck 231. The upper imaging unit 281 is provided adjacent to the upper chuck 230.

  Further, as shown in FIGS. 4, 5, and 11, 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 will be 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 rotate about the 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. 4, 5, and 11, 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). Are attached to the rail 295. The first lower chuck moving part 290 is configured to be movable along the rail 295.

  The pair of rails 295 are provided on 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 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). The pair of rails 297 is provided on a mounting table 298 provided on the bottom surface of the processing container 190.

  Next, the configuration of the upper chuck 230 and the lower chuck 231 will be described with reference to FIGS. 12A to 12D. As already described, in the present embodiment, both the upper chuck 230 and the lower chuck 231 have a deformation stage that is a holding surface capable of convex deformation. In such a convex deformation, it is preferable that the upper chuck 230 and the lower chuck 231 behave in the same manner. Therefore, in the present embodiment, the upper chuck 230 and the lower chuck 231 are arranged so that their orientations are upside down. The configuration is the same.

  For this reason, in FIGS. 12A to 12D, the components on the lower chuck 231 side are mainly exemplified. However, in FIGS. 12A to 12D, the reference numerals of the corresponding components on the upper chuck 230 side are also shown in parentheses.

  FIG. 12A is a perspective view showing the configuration of the lower chuck 231. FIG. 12B is a modified explanatory view of the lower chuck 231. FIG. 12C is a schematic cross-sectional view showing configurations of the upper chuck 230 and the lower chuck 231. FIG. 12D is a schematic plan view when the lower chuck 231 is viewed from above.

  As shown in FIGS. 12A and 12B, the lower chuck 231 includes a deformation stage 231a, a fixing ring 231b, and a base portion 231c. The deformation stage 231a is formed so as to have a substantially circular shape in plan view, and in a non-deformed state where the deformation stage 231a is not deformed, the surface side holding the lower wafer W2 is formed in a flat plate shape.

  The peripheral portion of the deformation stage 231a is fixed to the base portion 231c by a fixing ring 231b formed in a substantially annular shape. The base portion 231c is fixed to the first lower chuck moving portion 290 (see FIG. 4 and the like).

  Moreover, the deformation | transformation stage 231a is provided so that convex deformation | transformation is possible (refer the arrow 1201 of FIG. 12B). The term “convex deformation” as used herein refers to deformation so that the central portion of the deformation stage 231a is displaced to a position higher than the peripheral portion, and as shown in FIG. 12B, from the peripheral portion of the deformation stage 231a. It includes a case where the deformation stage 231a becomes a part of a substantially spherical shape by swelling toward the center.

  The structure for convexly deforming the deformation stage 231a is not limited. For example, an air pressure may be used, or a piezoelectric actuator or the like may be used. Here, the deformation stage 231a will not be described until it is convexly deformed based on the control by the control device 70, and a more specific structure will be described later with reference to FIGS. 15A to 16B.

  As shown in FIG. 12C, the deformation stage 231a of the lower chuck 231 is partitioned into a plurality of, for example, three regions 231aa, 231ab, and 231ac. These regions 231aa, 231ab, and 231ac are provided in this order from the central portion of the lower chuck 231 toward the peripheral portion (outer peripheral portion), as shown in FIG. 12D. The region 231aa has a circular shape in plan view, and the regions 231ab and 231ac have an annular shape in plan view.

  As shown in FIG. 12C, suction tubes 260a, 260b, and 260c for attracting and holding the lower wafer W2 are independently provided in each of the regions 231aa, 231ab, and 231ac. Different vacuum pumps 261a, 261b, 261c are connected to the suction tubes 260a, 260b, 260c, respectively. Thus, the lower chuck 231 is configured to be able to set the evacuation of the upper wafer W1 for each of the regions 231aa, 231ab, and 231ac.

  12D, the suction port of the suction tube 260a is arranged in the region 231aa, the suction port of the suction tube 260b is arranged in the region 231ab, and two suction ports of the suction tube 260c are arranged in a straight line in the region 231ac. However, it does not limit the number or arrangement position of each suction port.

  The upper chuck 230 side regions 230aa, 230ab, 230ac, the suction tubes 240a, 240b, 240c, and the vacuum pumps 241a, 241b, 241c are the lower chuck 231 side regions 231aa, 231ab, 231ac, the suction tubes 260a, 260b, 260c corresponds to the vacuum pumps 261a, 261b, 261c.

<3. Specific operation of surface modification device, surface hydrophilization device, and bonding device of bonding system>
Next, specific operations of the surface modification device 30, the surface hydrophilization device 40, and the bonding device 41 configured as described above will be described with reference to FIGS. 13 to 14I.

  FIG. 13 is a flowchart illustrating a part of a processing procedure of processing executed by the joining system 1. 14A to 14I are operation explanatory views (No. 1) to (No. 9) of the bonding apparatus 41. FIG. Various processes shown in FIG. 13 are executed based on control by the control device 70.

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

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

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

  Next, the upper wafer W1 is transferred by the transfer device 61 to the bonding device 41 of the second processing block G2. The upper wafer W <b> 1 carried into the bonding apparatus 41 is transferred to the position adjustment mechanism 210 by the transfer mechanism 201 through the transition 200. Then, the horizontal adjustment of the upper wafer W1 is adjusted by the position adjustment mechanism 210 (step S103).

  Thereafter, the upper wafer W <b> 1 is delivered 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 reversed by reversing the holding arm 221 (step S104). 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 W 1 is delivered from the reversing mechanism 220 to the upper chuck 230. The non-bonding surface W1n of the upper wafer W1 is sucked and held on the upper chuck 230 (step S105).

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

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

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

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

  Thereafter, the lower wafer W <b> 2 is transferred to the bonding apparatus 41 by the transfer device 61. The lower wafer W <b> 2 carried into the bonding apparatus 41 is transferred to the position adjustment mechanism 210 by the transfer mechanism 201 through the transition 200. Then, the horizontal adjustment of the lower wafer W2 is adjusted by the position adjustment mechanism 210 (step S108).

  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 S109). At this time, all the vacuum pumps 261a, 261b, 261c are operated, and the lower wafer W2 is evacuated in all the regions 231aa, 231ab, 231ac of the lower chuck 231. Then, the non-bonding surface W2n of the lower wafer W2 is attracted and held by the lower chuck 231 so that the bonding surface W2j of the lower wafer W2 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 S110).

  Prior to the position adjustment, as shown in FIG. 14A, a plurality of predetermined reference points A1 to A3, for example, three reference points A1 to A3 are set on the bonding surface W1j of the upper wafer W1. A plurality of predetermined points, for example, three reference points B1 to B3, are set on the joint surface W2j. As these reference points A1 to A3 and B1 to B3, for example, predetermined patterns formed on the upper wafer W1 and the lower wafer W2 are used, respectively. The number of reference points can be arbitrarily set.

  First, as shown in FIG. 14A, the horizontal positions of the upper imaging unit 281 and the lower imaging unit 291 are adjusted. Specifically, the lower chuck 231 is moved in the horizontal direction by the first lower chuck moving unit 290 and the second lower chuck moving unit 296 so that the lower imaging unit 291 is positioned substantially below the upper imaging unit 281. Then, the target X common to the upper imaging unit 281 and the lower imaging unit 291 is confirmed, and the horizontal position of the lower imaging unit 291 is fine so that the horizontal positions of the upper imaging unit 281 and the lower imaging unit 291 match. Adjusted.

  Next, as shown in FIG. 14B, after the lower chuck 231 is moved vertically upward by the first lower chuck moving unit 290, the horizontal position of the upper chuck 230 and the lower chuck 231 is adjusted.

  Specifically, the reference point B1 of the bonding surface W2j of the lower wafer W2 using the upper imaging unit 281 while moving the lower chuck 231 in the horizontal direction by the first lower chuck moving unit 290 and the second lower chuck moving unit 296. To B3 are sequentially imaged. At the same time, while moving the lower chuck 231 in the horizontal direction, the lower imaging unit 291 is used to sequentially image the reference points A1 to A3 of the bonding surface W1j of the upper wafer W1. 14B shows a state in which the upper imaging unit 281 images the reference point B1 of the lower wafer W2, and the lower imaging unit 291 images the reference point A1 of the upper wafer W1.

  The captured image data is output to the control device 70. In the control device 70, based on the image data picked up by the upper image pickup unit 281 and the image data picked up by the lower image pickup unit 291, the reference points A1 to A3 of the upper wafer W1 and the reference points B1 to B3 of the lower wafer W2 The horizontal position of the lower chuck 231 is adjusted by the first lower chuck moving unit 290 and the second lower chuck moving unit 296 so that the two match each other. Thus, the horizontal positions of the upper chuck 230 and the lower chuck 231 are adjusted, and the horizontal positions of the upper wafer W1 and the lower wafer W2 are adjusted.

  FIG. 14C shows the state of the upper chuck 230, the upper wafer W1, the lower chuck 231 and the lower wafer W2 after the processing up to step S110 is completed. As shown in FIG. 14C, the upper wafer W1 is evacuated and held in all the regions 230aa, 230ab, 230ac of the upper chuck 230, and the lower wafer W2 is also vacuumed in all the regions 231aa, 231ab, 231ac of the lower chuck 231. Pulled and held.

  Next, as shown in FIG. 14D, the deformation stages 230a and 231a of the upper chuck 230 and the lower chuck 231 are convexly deformed in a state where both the upper wafer W1 and the lower wafer W2 are evacuated and held (in the drawing). Arrow 1401, see step S111). As a result, the upper wafer W1 and the lower wafer W2 warp each other, with the central portion C approaching most and the peripheral portion E facing away from each other.

  Next, as shown in FIG. 14E, the lower chuck 231 is moved vertically upward by the first lower chuck moving unit 290 to adjust the vertical position of the upper chuck 230 and the lower chuck 231, and the upper chuck 230 is moved to the upper chuck 230. The vertical position between the held upper wafer W1 and the lower wafer W2 held by the lower chuck 231 is adjusted (step S112). This adjustment is appropriately performed in the process of bonding the upper wafer W1 and the lower wafer W2 thereafter.

  Next, bonding processing of the upper wafer W1 and the lower wafer W2 is performed. Specifically, as shown in FIG. 14F, the first lower chuck moving unit 290 causes the lower chuck 231 to be vertically upward so as to bring the upper wafer W1 and the lower wafer W2 that have been deformed and warped by deforming the deformation stages 230a and 231a toward each other. (See arrow 1402 in the figure). Then, the central portions C of the upper wafer W1 and the lower wafer W2 are brought into contact with each other (step S113).

  Then, if the central portions C of the upper wafer W1 and the lower wafer W2 are in contact with each other, as shown in FIG. 14G, the deformation stages 230a and 231a so that the convex shapes of the deformation stages 230a and 231a gradually return to a flat plate shape. Is gradually released (see arrow 1403 in the figure, step S114). At this time, the lower chuck 231 is moved vertically upward by the first lower chuck moving portion 290 so that the contact portion between the upper wafer W1 and the lower wafer W2 gradually expands from the central portion C toward the peripheral portion E (see FIG. See arrow 1404 in the figure, step S114).

  Thereby, the upper wafer W1 and the lower wafer W2 are gradually joined. 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 S101 and S106, first, Van der Waals force (intermolecular force) is generated between the bonding surfaces W1j and W2j. As a result, the joint surfaces W1j and W2j are joined together.

  Further, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are hydrophilized in steps S102 and S107, respectively, the hydrophilic groups between the bonding surfaces W1j and W2j are hydrogen-bonded, and the bonding surfaces W1j and W2j. They are firmly joined together. The joining by the van der Waals force and the hydrogen bond between the joining surfaces W1j and W2j gradually expands from the central portion C toward the peripheral portion E as the lower chuck 231 approaches the upper chuck 230.

  Note that the release of the convex deformation of the deformation stages 230a and 231a and the upward movement of the lower chuck 231 in step S114 are not only performed at a constant speed, but for example, the lower chuck 231 approaches the upper chuck 230 and moves upward. As the contact portion between the wafer W1 and the lower wafer W2 expands, the speed may be lowered. Thereby, it can suppress that a bubble arises in the peripheral part E vicinity of the upper wafer W1 and the lower wafer W2 after joining.

  Then, as shown in FIG. 14H, the deformation stages 230a and 231a return to the flat plate shape, and the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into contact with each other, so that the upper wafer W1 and the lower wafer W2 are in contact with each other. Joining (step S115). Then, the operation of the vacuum pumps 241a, 241b, 241c on the upper chuck 230 side is stopped, and the evacuation of the upper wafer W1 from the suction tubes 240a, 240b, 240c is stopped.

  Thereafter, as shown in FIG. 14I, the first lower chuck moving unit 290 moves the lower chuck 231 vertically downward (see an arrow 1405 in the drawing). Then, the operation of the vacuum pumps 261a, 261b, 261c on the lower chuck 231 side is stopped, the vacuuming of the lower wafer W2 from the suction pipes 260a, 260b, 260c is stopped, and the lower wafer W2 is sucked and held by the lower chuck 231. Is released. Thereby, the joining process in the joining apparatus 41 is complete | finished.

<4. Specific example of deformation structure of upper chuck and lower chuck>
Next, a specific example of the deformation structure of the upper chuck 230 and the lower chuck 231 will be described with reference to FIGS. 15A to 16B. 15A to 16B exemplarily mainly illustrate the lower chuck 231 side, but the upper chuck 230 side also has the same configuration except that the arrangement direction is upside down.

  First, as an example, a case where the deformed structure uses air pressure will be described with reference to FIGS. 15A to 15D. FIG. 15A is a schematic cross-sectional view showing a deformation structure of the deformation stage 231a. FIG. 15B is a schematic plan view showing a deformation structure of the deformation stage 231a. 15C and 15D are explanatory diagrams (No. 1) and (No. 2) of the displacement (Z displacement) in the Z direction and the displacement (X displacement) in the X direction of the deformation stage 231a.

  As shown in FIGS. 15A and 15B, when air pressure is used, the base portion 231c is provided with an air supply pipe 270a with a supply port opened on the upper surface of the base portion 231c. The air supply pipe 270a is connected to the vacuum pump 270b, and supplies and discharges air to and from the internal space surrounded by the upper surface of the base portion 231c and the rear surface of the deformation stage 231a by the operation of the vacuum pump 270b (arrow 1501 in FIG. 15A). reference).

  The deformation stage 231a is deformed according to a change in internal pressure due to supply / discharge of air from the air supply pipe 270a. That is, the deformation stage 231a is convexly deformed when air is supplied from the air supply pipe 270a and the internal pressure of the internal space increases, and the air is discharged from the air supply pipe 270a and the internal pressure of the internal space decreases. Returns to a flat shape (see arrow 1502 in FIG. 15A). In FIG. 15A and FIG. 15B, one air supply pipe 270a is provided, but a plurality of air supply pipes 270a may be provided.

  In addition, as a material for the deformation stage 231a, various materials such as an aluminum material, silicon carbide (SIC), and zirconia (ZrO2) can be used.

  Further, as shown in FIG. 15A, the deformation stage 231a has a substantially spherical shape on the back surface side, that is, the contour in the cross-sectional view on the back surface draws an arc from the center portion CT to the peripheral portion ET, The thickness Th is formed into a shape that gradually decreases.

  As shown in FIG. 15C, when the Z direction and the X displacement when the deformation stage 231a is convexly deformed with the vertical direction as the Z direction and the radial direction of the deformation stage 231a as the X direction, the deformation stage 231a This is because the X displacement can be made nearly linear as shown in FIG. 15D by making the rear surface side have a shape in which the thickness Th shown in FIG. 15A gradually decreases.

  Thereby, it becomes possible to displace the deformation | transformation stage 231a uniformly in the circumferential direction (gathering of radial direction). That is, the entire surface of the deformation stage 231a can be convexly deformed without deviation in the circumferential direction, which can contribute to improving the joining accuracy.

  As shown in FIGS. 15A and 15B, the deformation stage 231a has annular protrusions 231ad and 231ae arranged concentrically around the center portion CT on the back surface side thereof. In addition, although it is two here, the number is not limited.

  The annular protrusions 231ad and 231ae are provided with, for example, an annular protrusion 231ad corresponding to the boundary between the areas 231aa and 231ab, an annular protrusion 231ae corresponding to the boundary between the areas 231ab and 231ac, and the rear surface side of the deformation stage 231a. 231aa, 231ab, and 231ac are associated with each other.

  As a result, in the process in which the deformation stage 231a to be deformed is convexly deformed, the air supplied from the vacuum pump 270b via the air supply pipe 270a has a diameter exceeding the annular protrusions 231ae and 231ad as shown in FIG. 15B. While being supplied toward the central portion CT along the direction, each region 231ac, 231ab, 231aa can be easily distributed along the circumferential direction (see each arrow on the deformation stage 231a in the figure).

  That is, air can be uniformly supplied to the back surface side of the deformation stage 231a, which can contribute to convex deformation of the deformation stage 231a without unevenness.

  Next, as another example, a case where the deformation structure uses a piezoelectric actuator will be described with reference to FIGS. 16A and 16B.

  FIG. 16A is a schematic cross-sectional view showing another deformation structure of the deformation stage 231a. FIG. 16B is a schematic plan view showing another deformation structure of the deformation stage 231a. In FIGS. 16A and 16B, the lower chuck is denoted by reference numeral “231A”.

  As shown in FIGS. 16A and 16B, when a piezo actuator is used, a plurality of, for example, one piezo actuator PZ-C and four piezo actuators PZ-E are provided inside the base portion 231c.

  The piezo actuators PZ-C and PZ-E are respectively arranged such that the top piece TP which is a movable part is vertically upward. For example, the piezo actuator PZ-C is located at a position corresponding to the central portion CT of the deformation stage 231a. The actuators PZ-E are respectively arranged at equal intervals on the same circle near the peripheral edge ET of the deformation stage 231a. That is, it is preferable that the piezo actuators PZ-C and PZ-E are arranged so as to have symmetry as a whole depending on their arrangement positions. Thereby, it can contribute to providing force uniformly with respect to the deformation | transformation stage 231a.

  A center member 231ca formed in a substantially circular shape having a diameter larger than that of the top piece TP in a plan view is disposed above the piezo actuator PZ-C. Further, above the piezo actuator PZ-E, a ring member 231cb formed in a substantially annular shape extending in a width larger than the diameter of the top piece TP in a plan view is disposed.

  The piezo actuators PZ_C and PZ_E have piezo elements stacked inside, and raise and lower each top piece TP in accordance with a change in voltage from a voltage generator (not shown) connected to each. The deformation stage 231a deforms according to the movement of each top piece TP.

  Specifically, the piezo actuator PZ_C moves the center member 231ca in contact with the top piece TP up and down by the top piece TP (see an arrow 1601 in FIG. 16A). Further, the piezo actuator PZ_E moves the ring member 231cb in contact with each top piece TP up and down by the top piece TP (see an arrow 1602 in FIG. 16A).

  Then, in accordance with the movements of the center member 231ca and the ring member 231cb, the deformation stage 231a is convexly deformed or the surface returns to a flat plate shape (see an arrow 1603 in FIG. 16A). The center member 231ca and the ring member 231cb are examples of “dispersing members” that play a role of dispersing the load and uniformly deforming the deformation stage 231a.

  As described above, the deformation structure of the deformation stage 231a can also be configured by using the piezoelectric actuators PZ_C and PZ_E. Needless to say, the actuator is not limited to the piezoelectric actuators PZ_C and PZ_E as long as the input energy can be converted into a physical motion in the vertical direction.

  In the bonding system 1 according to the present embodiment configured as described above, the upper chuck 230 and the lower chuck 231 are convexly deformed with the same behavior in the bonding apparatus 41, and the upper wafer W1 and the lower wafer are held by these. Since W2 is warped substantially the same and then bonded, it is possible to prevent a phenomenon in which one of the upper wafer W1 and the lower wafer W2 extends from the other. Therefore, according to the present embodiment, the bonding quality of the substrates can be improved.

  Further, in the bonding system 1 according to the present embodiment, it is not necessary to use a technique of preheating the upper wafer W1 and the lower wafer W2 in the bonding apparatus 41. Therefore, distortion due to the temperature distribution difference does not occur. That is, according to the present embodiment, the bonding quality of the substrates can be improved.

  Further, in the bonding system 1 according to the present embodiment, when the upper chuck 230 and the lower chuck 231 are approached in the bonding apparatus 41, the contact portion between the upper wafer W1 and the lower wafer W2 expands, for example, at a low speed. Therefore, it is possible to suppress the generation of bubbles in the vicinity of the peripheral edge E of the upper wafer W1 and the lower wafer W2 after bonding. Therefore, according to the present embodiment, the bonding quality of the substrates can be improved.

  As described above, the bonding apparatus 41 according to this embodiment includes the upper chuck 230 (corresponding to an example of “first holding part”), the lower chuck 231 (corresponding to an example of “second holding part”), Deformation stages 230a and 231a and a control device 70 (corresponding to an example of a “control unit”) are provided.

  The upper chuck 230 holds the upper wafer W1 (corresponding to an example of “first substrate”) on the lower surface side. The lower chuck 231 is provided below the upper chuck 230, and holds the lower wafer W2 (corresponding to an example of “second substrate”) on the upper surface side so as to face the upper wafer W1.

  The deformation stages 230a and 231a are disposed as the lower surface of the upper chuck 230 and the upper surface of the lower chuck 231 and are provided so as to be capable of convex deformation while holding the upper wafer W1 and the lower wafer W2, respectively.

  The control device 70 brings the center portions C of the upper wafer W1 and the lower wafer W2 into contact with each other by causing the upper chuck 230 and the lower chuck 231 to approach each other with the deformation stages 230a and 231a being convexly deformed, and then the deformation stage. The upper wafer W1 and the lower wafer W2 are joined by further bringing the upper chuck 230 and the lower chuck 231 closer while releasing the convex deformation of 230a and 231a.

  Therefore, according to the bonding apparatus 41 according to the present embodiment, the bonding quality of the substrates can be improved.

  In the above-described embodiment, the case where the lower chuck 231 approaches the upper chuck 230 along the vertical direction has been described as an example. However, the upper chuck 230 may approach the lower chuck 231.

  In the above-described embodiment, the case where air is supplied using a vacuum pump or the like has been described as an example. However, an electropneumatic regulator or the like that can supply air with a predetermined pressure while strictly controlling the air is used. Also good.

  In the above-described embodiment, the case where air is supplied to and discharged from the inner space on the back surface side of the deformation stages 230a and 231a has been described as an example. However, it is only necessary to change the internal pressure of the inner space. I just need it.

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

DESCRIPTION OF SYMBOLS 1 Joining system 2 Carry-in / out station 3 Processing station 30 Surface modification apparatus 40 Surface hydrophilization apparatus 41 Joining apparatus 70 Control apparatus 230 Upper chuck 230a Deformation stage 231,231A Lower chuck 231a Deformation stage 231ad Annular protrusion 231ae Annular protrusion 231b Fixed ring 231c Base part 231ca Center member 231cb Ring member PZ-C Piezo actuator PZ-E Piezo actuator TP Top piece W1 Upper wafer W2 Lower wafer

Claims (8)

A first holding unit for holding the first substrate on the lower surface side;
A second holding unit that is provided below the first holding unit and holds the second substrate facing the first substrate on the upper surface side;
Arranged as the lower surface of the first holding part and the upper surface of the second holding part , formed so that the back side is substantially spherical, and convexly deformed while holding the first substrate and the second substrate, respectively. A deformation stage that is capable of
After bringing the first holding part and the second holding part close together in a state where the deformation stage is convexly deformed, the center parts of the first substrate and the second substrate are brought into contact with each other, And a controller that joins the first substrate and the second substrate by bringing the first holding unit and the second holding unit closer to each other while releasing the convex deformation. The first holding part and the second holding part are respectively
A base part;
A fixing member for fixing the deformation stage to the base portion while securing an internal space between the back surface side of the deformation stage and the base portion;
A fluid supply pipe provided so that fluid can be supplied to and discharged from the internal space,
The deformation stage is
The joining apparatus according to claim 1, wherein convex deformation is provided according to an internal pressure of the internal space that changes depending on fluid supplied and discharged from the fluid supply pipe based on control of the control unit. The deformation stage is
It has a substantially circular shape in plan view, and in a non-deformed state, the surface side that holds the first substrate or the second substrate is formed to be a flat plate shape, and the peripheral portion is thicker than the thickness of the central portion. bonding apparatus according to claim 1 or 2, characterized in that towards the thick is formed on the small shape. The deformation stage is
The joining apparatus according to claim 1, 2 or 3 , further comprising an annular protrusion arranged concentrically around the central portion of the deformation stage. The first holding part and the second holding part are respectively
The actuator according to claim 1, further comprising an actuator that has a movable part capable of moving along a vertical direction and deforms the deformation stage by applying a force to the deformation stage by the movement of the movable part . The joining apparatus as described in any one . A plurality of the actuators are provided,
The joining apparatus according to claim 5 , wherein the joining devices are arranged so as to have symmetry as a whole depending on respective placement positions. A width larger than the diameter of the movable part is provided between the movable part and the deformation stage, and receives the contact of the movable part and distributes the force from the movable part to the deformation stage. bonding apparatus according to claim 5 or 6, characterized in that it comprises a dispersion member for applying to. The joining apparatus according to claim 5, 6 or 7 , wherein the actuator is a piezoelectric actuator in which piezoelectric elements are stacked.

Images