Connecting device

Abstract

To provide technology with which the joint quality of polymerized substrates can be improved.SOLUTION: A joining device according to one aspect of the present disclosure comprises a first holding unit, a second holding unit, a striker, a processing container, a gas discharge unit, and a control unit. The first holding unit holds a first substrate from above by suction. The second holding unit holds a second substrate from below by suction. The striker presses the central part of the first substrate from above to bring it into contact with the second substrate. The processing container accommodates the first and second holding units and the striker. The gas discharge unit discharges a gas differing in humidity from the atmosphere in the processing container. The control unit controls each unit. The control unit also discharges a gas from the gas discharge unit to between the first substrate and the second substrate immediately before the first substrate placed face-to-face with the second substrate is pressed by the striker.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present disclosure relates to a joining device. Place Regarding. [Background technology]

[0002] Conventionally, a known method for bonding substrates such as semiconductor wafers together involves modifying the surfaces of the substrates to be bonded, making the modified surfaces of the substrates hydrophilic, and bonding the hydrophilized substrates together by van der Waals forces and hydrogen bonds (intermolecular forces) (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-005058 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can improve the bonding quality of laminated substrates. [Means for solving the problem]

[0005] A bonding apparatus according to one aspect of the present disclosure includes a first holding unit, a second holding unit, a striker, a processing vessel, and a gas discharge unit. Gas suction part The first holding unit sucks and holds the first substrate from above. The second holding unit sucks and holds the second substrate from below. The striker presses the center of the first substrate from above to bring it into contact with the second substrate. The processing vessel accommodates the first holding unit, the second holding unit, and the striker. The gas discharge unit discharges a gas having a humidity different from that of the atmosphere in the processing vessel. Between the first substrate and the second substrate facing each other Discharge. The gas suction unit suctions the atmosphere between the first substrate and the second substrate, which face each other. In plan view, the gas discharge unit and the gas suction unit are positioned to face each other with respect to the centers of the first substrate and the second substrate. [Effects of the Invention]

[0006] According to the present disclosure, the bonding quality of laminated substrates can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic plan view showing the configuration of a bonding system according to an embodiment. [Figure 2] FIG. 2 is a schematic side view showing the configuration of the joint system according to the embodiment. [Figure 3] FIG. 3 is a schematic side view of the upper wafer and the lower wafer according to the embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the configuration of a surface modification apparatus according to an embodiment. [Figure 5] FIG. 5 is a schematic plan view showing the configuration of the bonding device according to the embodiment. [Figure 6] FIG. 6 is a schematic side view showing the configuration of the joining device according to the embodiment. [Figure 7] FIG. 7 is a schematic side view showing the configuration of the upper chuck and the lower chuck of the joining device according to the embodiment. [Figure 8] FIG. 8 is an enlarged side view showing the configuration of the suction and discharge mechanism according to the embodiment. [Figure 9] FIG. 9 is a flowchart illustrating a part of the processing procedure of the processing executed by the joint system according to the embodiment. [Figure 10] FIG. 10 is a timing chart showing the operation of each unit in the joining process according to the embodiment. [Figure 11] FIG. 11 is a diagram for explaining details of the joining process according to the embodiment. [Figure 12] FIG. 12 is a timing chart showing the operation of each unit in the joining process according to the modified embodiment. [Figure 13] FIG. 13 is a top view showing an example of the arrangement of the gas suction section and the gas discharge section according to a modified example of the embodiment. [Figure 14] FIG. 14 is a top view showing another example of the arrangement of the gas suction section and the gas discharge section according to the modified example of the embodiment. [Figure 15]FIG. 15 is a flowchart showing the processing procedure of the joining process executed by the joining device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the bonding apparatus and bonding method disclosed herein will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments described below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of elements may differ from reality. Furthermore, the dimensional relationships and ratios may differ between the drawings.

[0009] Conventionally, a known method for bonding substrates such as semiconductor wafers involves modifying the surfaces of the substrates to be bonded, making the modified surfaces of the substrates hydrophilic, and bonding the hydrophilized substrates together using van der Waals forces and hydrogen bonds (intermolecular forces).

[0010] On the other hand, when hydrophilized substrates are bonded together to form a laminated substrate, voids (hereinafter referred to as edge voids) may occur at the periphery of the laminated substrate.Furthermore, when forming such a laminated substrate, variations in the state of the bonding interface may occur, resulting in significant distortion of the laminated substrate.

[0011] If the bonding quality of the laminated substrate deteriorates in this way, there is a risk that the yield of elements formed in the laminated substrate will decrease.

[0012] Therefore, there is a need for a technology that can overcome the above-mentioned problems and improve the bonding quality of laminated substrates.

[0013] <Configuration of the joining system> First, the configuration of a bonding system 1 according to an 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 an embodiment, and FIG. 2 is a schematic side view of the same. Also, FIG. 3 is a schematic side view of an upper wafer and a lower wafer according to an embodiment. Note that, for ease of understanding, the drawings referred to below may show an orthogonal coordinate system in which the vertically upward direction is the positive direction of the Z axis.

[0014] The bonding system 1 shown in FIG. 1 forms a laminated wafer T by bonding a first substrate W1 and a second substrate W2 together.

[0015] 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. The second substrate W2 may have electronic circuits formed thereon.

[0016] 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."

[0017] 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."

[0018] 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.

[0019] 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 an overlapped wafer T.

[0020] 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.

[0021] 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 overlapping wafer T between the cassettes C1 to C3 placed on the mounting plate 11 and a third processing block G3 of the processing station 3, which will be described later.

[0022] 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.

[0023] 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 negative Y-axis side in FIG. 1), and a second processing block G2 is provided on the back side of processing station 3 (the positive Y-axis side in FIG. 1). Furthermore, a third processing block G3 is provided on the loading / unloading station 2 side of processing station 3 (the negative X-axis side in FIG. 1).

[0024] The first processing block G1 is provided with a surface modification device 30 that modifies the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2 using plasma of a processing gas. The surface modification device 30 breaks SiO2 bonds on the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2 to form single-bonded SiO, thereby modifying the bonding surfaces W1j, W2j so that they are more easily hydrophilized thereafter.

[0025] In the surface modification apparatus 30, for example, a given process gas is excited to generate plasma and ionized in a reduced pressure atmosphere. Then, ions of elements contained in the process gas are irradiated onto the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2, thereby subjecting the bonding surfaces W1j, W2j to plasma processing and modification. Details of the surface modification apparatus 30 will be described later.

[0026] The second processing block G2 is provided with a surface hydrophilization device 40 and a bonding device 41. The surface hydrophilization device 40 hydrophilizes the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2, for example, by using pure water, and cleans the bonding surfaces W1j and W2j.

[0027] 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 being 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.

[0028] The bonding device 41 bonds the upper wafer W1 and the lower wafer W2 together. Details of the bonding device 41 will be described later.

[0029] As shown in FIG. 2, in the third processing block G3, transition (TRS) devices 50 and 51 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T are provided in two stages in this order from the bottom.

[0030] 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.

[0031] The transfer device 61 moves within the transfer region 60 and transfers the upper wafer W1, the lower wafer W2, and the overlapping 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.

[0032] The bonding system 1 also includes a control device 4. The control device 4 controls the operation of the bonding system 1. The control device 4 is, for example, a computer, and includes a control unit 5 and a storage unit 6. The storage unit 6 stores programs for controlling various processes such as the bonding process. The control unit 5 controls the operation of the bonding system 1 by reading and executing the programs stored in the storage unit 6.

[0033] Such a program may be recorded on a computer-readable recording medium and installed from that recording medium into the storage unit 6 of the control device 4. Examples of computer-readable recording media include hard disks (HDs), flexible disks (FDs), compact disks (CDs), magnetic optical disks (MOs), and memory cards.

[0034] <Configuration of the surface modification device> Next, the configuration of the surface modification device 30 will be described with reference to Fig. 4. Fig. 4 is a schematic cross-sectional view showing the configuration of the surface modification device 30.

[0035] 4, the surface modification apparatus 30 has a processing vessel 70 whose interior can be sealed. A loading / unloading port 71 for the upper wafer W1 or the lower wafer W2 is formed on the side of the processing vessel 70 facing the transfer region 60 (see FIG. 1), and a gate valve 72 is provided at the loading / unloading port 71.

[0036] A stage 80 is disposed inside the processing vessel 70. The stage 80 is, for example, a lower electrode and is made of a conductive material such as aluminum. A plurality of driving units 81, each including, for example, a motor, are provided below the stage 80. The plurality of driving units 81 raise and lower the stage 80.

[0037] An exhaust ring 103 having a plurality of baffle holes is disposed between the stage 80 and the inner wall of the processing vessel 70. The exhaust ring 103 allows the atmosphere in the processing vessel 70 to be uniformly exhausted from the processing vessel 70.

[0038] A power feed rod 104 made of a conductor is connected to the underside of the stage 80. A first high-frequency power supply 106 is connected to the power feed rod 104 via a matching box 105, which may be a blocking capacitor or the like. During plasma processing, a given high-frequency voltage is applied to the stage 80 from the first high-frequency power supply 106.

[0039] An upper electrode 110 is disposed inside the processing vessel 70. The upper surface of the stage 80 and the lower surface of the upper electrode 110 are disposed parallel to each other and facing each other with a given gap therebetween. The gap between the upper surface of the stage 80 and the lower surface of the upper electrode 110 is adjusted by a driving unit 81.

[0040] The upper electrode 110 is grounded and connected to the ground potential. Since the upper electrode 110 is grounded in this manner, damage to the lower surface of the upper electrode 110 can be suppressed during plasma processing.

[0041] In this manner, a high frequency voltage is applied from the first high frequency power supply 106 to the stage 80 serving as the lower electrode, thereby generating plasma inside the processing chamber 70 .

[0042] In the embodiment, the stage 80, the power feed rod 104, the matching box 105, the first high frequency power supply 106, the upper electrode 110, and the matching box are an example of a plasma generation mechanism that generates plasma of the processing gas in the processing chamber 70. The first high frequency power supply 106 is controlled by the control unit 5 of the control device 4 described above.

[0043] A hollow portion 120 is formed inside the upper electrode 110. A gas supply pipe 121 is connected to the hollow portion 120. The gas supply pipe 121 is connected to a gas supply source 122 that stores a processing gas and a static elimination gas therein. The gas supply pipe 121 is also provided with a supply device group 123 that includes valves and flow rate regulators that control the flow of the processing gas and the static elimination gas.

[0044] The processing gas and static elimination gas supplied from the gas supply source 122 are flow-controlled by a supply device group 123 and introduced into the hollow portion 120 of the upper electrode 110 via a gas supply pipe 121. For example, oxygen gas, nitrogen gas, argon gas, etc. are used as the processing gas. For example, inert gas such as nitrogen gas or argon gas is used as the static elimination gas.

[0045] A baffle plate 124 for promoting uniform diffusion of the processing gas and the static elimination gas is provided inside the hollow portion 120. A large number of small holes are provided in the baffle plate 124. A large number of gas outlets 125 are formed on the lower surface of the upper electrode 110 to eject the processing gas and the static elimination gas from the hollow portion 120 into the processing vessel 70.

[0046] An intake port 130 is formed in the processing vessel 70. An intake pipe 132 communicating with a vacuum pump 131 that reduces the atmosphere inside the processing vessel 70 to a given vacuum level is connected to the intake port 130.

[0047] The upper surface of the stage 80, i.e., the surface facing the upper electrode 110, is a horizontal surface that is circular in plan view and has a diameter larger than that of the upper wafer W1 and the lower wafer W2. A stage cover 90 is placed on the upper surface of the stage 80, and the upper wafer W1 or the lower wafer W2 is placed on a placement portion 91 of the stage cover 90.

[0048] <Configuration of the joining device> Next, the configuration of the joining device 41 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a schematic plan view showing the configuration of the joining device 41 according to the embodiment, and Fig. 6 is a schematic side view showing the configuration of the joining device 41 according to the embodiment.

[0049] 5, the bonding apparatus 41 has a processing container 190 whose interior can be sealed. A loading / unloading port 191 for the upper wafer W1, the lower wafer W2, and the overlapping wafer T is formed on the side surface of the processing container 190 on the transfer region 60 side, and an opening / closing shutter 192 is provided at the loading / unloading port 191.

[0050] The interior of the processing vessel 190 is divided into a transfer region T1 and a processing region T2 by an inner wall 193. The above-mentioned loading / unloading port 191 is formed on the side surface of the processing vessel 190 in the transfer region T1. In addition, loading / unloading ports 194 for the upper wafer W1, the lower wafer W2, and the overlapping wafer T are also formed in the inner wall 193.

[0051] Furthermore, a humidity maintaining mechanism (not shown) maintains a given constant humidity inside the processing vessel 190. This allows the bonding device 18 to perform the bonding process of the upper wafer W1 and the lower wafer W2 in a stable environment.

[0052] A transition 200 is provided on the negative Y-axis side of the transfer region T1 for temporarily placing the upper wafer W1, the lower wafer W2, and the overlapping wafer T. The transition 200 is formed, for example, in two stages, and any two of the upper wafer W1, the lower wafer W2, and the overlapping wafer T can be placed on the transition 200 at the same time.

[0053] A transfer mechanism 201 is provided in the transfer region T1. The transfer mechanism 201 has a transfer arm that is movable, for example, vertically, horizontally, and around a vertical axis. The transfer mechanism 201 transfers the upper wafer W1, the lower wafer W2, and the overlapped wafer T within the transfer region T1 or between the transfer region T1 and the processing region T2.

[0054] A position adjustment mechanism 210 that adjusts the horizontal orientation of the upper wafer W1 and the lower wafer W2 is provided on the positive Y-axis side of the transfer region T1. The position adjustment mechanism 210 detects the positions of the notches of the upper wafer W1 and the lower wafer W2 with a detection unit (not shown) while rotating the upper wafer W1 and the lower wafer W2 that are held by suction on a holding unit (not shown).

[0055] As a result, the position adjustment mechanism 210 adjusts the position of the notch portion to adjust the horizontal orientation of the upper wafer W1 and the lower wafer W2. Also, a reversing mechanism 220 that reverses the front and back surfaces of the upper wafer W1 is provided in the transfer region T1.

[0056] 6, an upper chuck 230 and a lower chuck 231 are provided in the processing region T2. ​​The upper chuck 230 suction-holds the upper wafer W1 from above. The lower chuck 231 is provided below the upper chuck 230 and suction-holds the lower wafer W2 from below. The upper chuck 230 is an example of a first holding unit, and the lower chuck 231 is an example of a second holding unit.

[0057] 6, the upper chuck 230 is supported by a support member 300 provided on the ceiling surface of the processing vessel 190. The support member 300 is provided with an upper imaging unit (not shown) that captures an image of the bonding surface W2j of the lower wafer W2 held by the lower chuck 231. The upper imaging unit is provided adjacent to the upper chuck 230.

[0058] 5 and 6, the lower chuck 231 is supported by a first lower chuck moving part 310 provided below the lower chuck 231. The first lower chuck moving part 310 moves the lower chuck 231 in the horizontal direction (Y-axis direction), as will be described later. The first lower chuck moving part 310 is configured to be able to move the lower chuck 231 vertically and to rotate it around a vertical axis.

[0059] 5, the first lower chuck moving part 310 is provided with a lower imaging part (not shown) that images the bonding surface W1j of the upper wafer W1 held by the upper chuck 230. The lower imaging part is provided adjacent to the lower chuck 231.

[0060] 5 and 6, the first lower chuck moving part 310 is provided on the lower surface side of the first lower chuck moving part 310 and is attached to a pair of rails 315 extending in the horizontal direction (Y-axis direction). The first lower chuck moving part 310 is configured to be movable along the rails 315.

[0061] The pair of rails 315 is provided on the second lower chuck moving part 316. The second lower chuck moving part 316 is attached to a pair of rails 317 that are provided on the lower surface side of the second lower chuck moving part 316 and extend in the horizontal direction (X-axis direction).

[0062] The second lower chuck moving part 316 is configured to be movable along rails 317, i.e., to move the lower chuck 231 in the horizontal direction (X-axis direction). The pair of rails 317 is provided on a mounting table 318 provided on the bottom surface of the processing vessel 190.

[0063] Next, the configuration of the upper chuck 230 and the lower chuck 231 in the joining device 41 will be described with reference to Fig. 7. Fig. 7 is a schematic side view showing the configuration of the upper chuck 230 and the lower chuck 231 of the joining device 41 according to the embodiment.

[0064] 7, the upper chuck 230 is partitioned into a plurality of, for example, three regions 230a, 230b, and 230c. These regions 230a, 230b, and 230c are provided in this order from the center toward the peripheral edge (outer periphery) of the upper chuck 230. The region 230a has a circular shape in a plan view, and the regions 230b and 230c have annular shapes in a plan view.

[0065] As shown in FIG. 7, a central suction pipe 240a, an intermediate suction pipe 240b, and a peripheral suction pipe 240c for suction-holding the upper wafer W1 are independently provided in each of the regions 230a, 230b, and 230c.

[0066] The central suction pipe 240a suction-holds the central portion of the upper wafer W1. The peripheral suction pipe 240c suction-holds the peripheral portion W1e of the upper wafer W1. The intermediate suction pipe 240b suction-holds the intermediate portion of the upper wafer W1, which is between the central portion and the peripheral portion W1e.

[0067] A vacuum pump 241a is connected to the central suction pipe 240a, a vacuum pump 241b is connected to the intermediate suction pipe 240b, and a vacuum pump 241c is connected to the peripheral suction pipe 240c. In this manner, the upper chuck 230 is configured so that the vacuum suction of the upper wafer W1 can be set for each of the regions 230a, 230b, and 230c.

[0068] Furthermore, in the bonding apparatus 41, it is possible to determine whether the upper wafer W1 and the lower wafer W2 are bonded at each position by monitoring the suction status of the suction pipe at each position. For example, when the vacuum pump 241b is operating, if the pressure inside the intermediate suction pipe 240b changes from negative to atmospheric pressure, it can be considered that the upper wafer W1 has separated from the intermediate suction pipe 240b.

[0069] Then, the control unit 5 can determine that the upper wafer W1 has been bonded to the lower wafer W2 at the middle portion of the wafer W, since the upper wafer W1 has been separated from the middle suction pipe 240b.

[0070] A through-hole 243 is formed in the center of the upper chuck 230, penetrating the upper chuck 230 in the thickness direction. The center of the upper chuck 230 corresponds to the center W1c of the upper wafer W1 held by suction on the upper chuck 230. A pressing pin 253 of a striker 250 is inserted into the through-hole 243.

[0071] The striker 250 is provided on the upper surface of the upper chuck 230 and presses the center W1c of the upper wafer W1 with a pressing pin 253. The pressing pin 253 is provided so as to be linearly movable along a vertical axis by a cylinder part 251 and an actuator part 252, and presses the opposing substrate (the upper wafer W1 in this embodiment) with its tip.

[0072] Specifically, the pressing pin 253 serves as a starter that first brings the center W1c of the upper wafer W1 and the center W2c of the lower wafer W2 into contact with each other when bonding the upper wafer W1 and the lower wafer W2 together, as will be described later.

[0073] The lower chuck 231 is substantially disk-shaped and is partitioned into a plurality of regions, for example, two regions 231a and 231b. These regions 231a and 231b are provided in this order from the center toward the periphery of the lower chuck 231. The region 231a has a circular shape in a plan view, and the region 231b has an annular shape in a plan view.

[0074] 7, suction pipes 260a and 260b for suction-holding the lower wafer W2 are independently provided in the respective regions 231a and 231b. Different vacuum pumps 261a and 261b are connected to the respective suction pipes 260a and 260b. In this manner, the lower chuck 231 is configured so that the vacuum suction of the lower wafer W2 can be set for each of the regions 231a and 231b.

[0075] Stopper members 263 are provided at a plurality of locations, for example, five locations, on the periphery of the lower chuck 231 to prevent the upper wafer W1, the lower wafer W2, and the overlapped wafer T from jumping out or slipping off the lower chuck 231.

[0076] The bonding apparatus 41 also includes a suction / discharge mechanism 270 that sucks the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other and further discharges low-humidity gas between the upper wafer W1 and the lower wafer W2 facing each other.

[0077] The suction and discharge mechanism 270 has a main body 271, a gas suction part 272 (see FIG. 8), and a gas discharge part 273. The main body 271 has, for example, an annular shape, and is disposed so as to surround the periphery of the upper chuck 230.

[0078] The gas suction unit 272 sucks the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other. The gas suction unit 272 will be described in detail later.

[0079] The gas discharge unit 273 discharges low-humidity gas between the upper wafer W1 and the lower wafer W2 facing each other from a plurality of discharge ports 273d (see FIG. 8) formed in the main body 271. In the embodiment, the low-humidity gas is a gas having a lower humidity than the atmosphere in the processing container 190, such as an inert gas (such as nitrogen gas) having a lower humidity than the atmosphere in the processing container 190.

[0080] The gas discharge unit 273 has a gas supply source 273a, a valve 273b, a flow rate regulator 273c, and a plurality of discharge ports 273d. The low humidity gas supplied from the gas supply source 273a has its flow rate controlled by the valve 273b and the flow rate regulator 273c, and is discharged from the discharge ports 273d.

[0081] <Configuration of suction and discharge mechanism> Next, the detailed configuration of the suction and discharge mechanism 270 will be described with reference to Fig. 8. Fig. 8 is an enlarged side view showing the configuration of the suction and discharge mechanism 270 according to the embodiment. Fig. 8 is an enlarged cross-sectional view showing a state in which the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are brought close to each other by a preset distance and the lower chuck 231 is located at the home position.

[0082] As described above, the suction and discharge mechanism 270 has the main body 271, the gas suction part 272, and the gas discharge part 273. The suction and discharge mechanism 270 further has a support part 274, a sealing part 275, and a sensor part 276.

[0083] The main body portion 271 has, for example, a circular ring shape, and is disposed so as to surround the peripheral edge of the upper chuck 230 while maintaining a given distance from the peripheral edge of the upper chuck 230 .

[0084] The gas suction unit 272 has a plurality of suction ports 272a, a valve 272b, and a suction mechanism 272c. The plurality of suction ports 272a are formed on the inner peripheral surface of the main body 271 and are evenly spaced in the circumferential direction.

[0085] The suction mechanism 272c is, for example, a pump, and is connected to the plurality of suction ports 272a via the valve 272b. The control unit 5 can operate the valve 272b and the suction mechanism 272c to suck the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other through the plurality of suction ports 272a.

[0086] The gas discharge unit 273 has a gas supply source 273a (see FIG. 7), a valve 273b, a flow rate regulator 273c (see FIG. 7), and a plurality of discharge ports 273d. The plurality of discharge ports 273d are formed on the inner peripheral surface of the main body 271 at equal intervals in the circumferential direction. In the example of FIG. 8, the discharge ports 273d and the suction port 272a are disposed close to each other.

[0087] The control unit 5 can operate the valve 273b and the flow rate regulator 273c to discharge the low-humidity gas from the plurality of discharge ports 273d between the upper wafer W1 and the lower wafer W2 facing each other.

[0088] The support portion 274 supports the main body portion 271 on the upper chuck 230. The sealing portion 275 has, for example, a circular ring shape, and is attached to the lower surface of the main body portion 271. The sealing portion 275 is made of an elastically deformable material.

[0089] Here, in the bonding apparatus 41 according to the embodiment, when the lower wafer W2 held by the lower chuck 231 is positioned at the home position relative to the upper wafer W1 held by the upper chuck 230, the upper wafer W1 and the lower wafer W2 are sealed from the outside.

[0090] That is, when the lower wafer W2 is located at the home position, the upper wafer W1 and the lower wafer W2 are shielded from the outside (the atmosphere inside the processing vessel 190 (see FIG. 5)) by the upper chuck 230, the lower chuck 231, the main body 271, the support portion 274, and the sealing portion 275.

[0091] Since the sealing portion 275 is elastically deformable, when the upper wafer W1 and the lower wafer W2 are brought closer to each other from the state shown in FIG. 8 and the lower wafer W2 is positioned at the bonding position, the sealing portion 275 does not become an obstruction factor.

[0092] In the present disclosure, the bond position refers to the position of the lower chuck 231 when performing a process of pressing the center portion W1c of the upper wafer W1 with the striker 250. When the lower chuck 231 is at the bond position, the gap between the upper wafer W1 and the lower wafer W2 is, for example, about 50 μm.

[0093] In the present disclosure, the home position refers to a position where the lower chuck 231 is temporarily placed on standby when starting a process of placing the lower chuck 231 at a bonding position. When the lower chuck 231 is in the home position, the horizontal position adjustment of the upper wafer W1 and the lower wafer W2 is completed, and the gap between the upper wafer W1 and the lower wafer W2 is, for example, approximately 80 μm to 100 μm.

[0094] The sensor unit 276 is provided adjacent to at least one of the upper wafer W1 and the lower wafer W2 (upper wafer W1 in the figure). The sensor unit 276 is provided, for example, at a position adjacent to the upper wafer W1 on the upper chuck 230. The sensor unit 276 includes a humidity sensor and the like.

[0095] The control unit 5 operates the sensor unit 276 to measure the humidity of the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other.

[0096] <Processing performed by the joining system> Next, the details of the processes executed by the bonding system 1 according to the embodiment will be described with reference to Fig. 9 to Fig. 11. Note that the various processes shown below are executed based on the control by the control unit 5 of the control device 4.

[0097] 9 is a flowchart showing a part of a processing procedure executed by the bonding system 1 according to the embodiment. 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 given placement plate 11 of the carry-in / out station 2.

[0098] Thereafter, the upper wafer W1 is removed from the cassette C1 by the transfer device 22 and transferred to the transition device 50 in the third processing block G3 of the processing station 3.

[0099] Next, the upper wafer W1 is transferred by the transfer device 61 to the surface modification device 30 in the first processing block G1. At this time, the gate valve 72 is opened, and the inside of the processing container 70 is exposed to atmospheric pressure. In the surface modification device 30, the processing gas is excited into plasma and ionized in a given reduced pressure atmosphere.

[0100] The ions thus generated are irradiated onto the bonding surface W1j of the upper wafer W1, and the bonding surface W1j is subjected to plasma processing, whereby dangling bonds of silicon atoms are formed on the outermost surface of the bonding surface W1j, thereby modifying the bonding surface W1j of the upper wafer W1 (step S101).

[0101] Next, the upper wafer W1 is transferred to the surface hydrophilization device 40 in the second processing block G2 by the transfer device 61. In the surface hydrophilization device 40, pure water is supplied onto the upper wafer W1 while the upper wafer W1 held by a spin chuck is being rotated.

[0102] The supplied pure water then diffuses over the bonding surface W1j of the upper wafer W1. As a result, in the surface modification device 30, OH groups (silanol groups) are attached to the dangling bonds of silicon atoms on the modified bonding surface W1j of the upper wafer W1, making the bonding surface W1j hydrophilic (step S102). The pure water also cleans the bonding surface W1j of the upper wafer W1.

[0103] Next, the upper wafer W1 is transferred to the bonding device 41 in the second processing block G2 by the transfer device 61. The upper wafer W1 transferred into the bonding device 41 is transferred to the position adjustment mechanism 210 via the transition 200. Then, the horizontal orientation of the upper wafer W1 is adjusted by the position adjustment mechanism 210 (step S103).

[0104] Thereafter, the upper wafer W1 is transferred from the position adjustment mechanism 210 to the reversing mechanism 220. Subsequently, in the transfer region T1, the reversing mechanism 220 is operated to reverse the front and rear surfaces of the upper wafer W1 (step S104). That is, the bonding surface W1j of the upper wafer W1 faces downward.

[0105] Thereafter, the reversing mechanism 220 rotates and moves to below the upper chuck 230. Then, the upper wafer W1 is transferred from the reversing mechanism 220 to the upper chuck 230. The upper wafer W1 is held by suction at the non-bonding surface W1n thereof on the upper chuck 230 (step S105).

[0106] While the upper wafer W1 is being processed in the above-described steps S101 to S105, the lower wafer W2 is being processed. First, the transfer device 22 removes the lower wafer W2 from the cassette C2 and transfers it to the transition device 50 in the processing station 3.

[0107] 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 S106). Note that step S106 is the same process as step S101 described above.

[0108] 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 (step S107). Note that step S107 is the same process as step S102 described above.

[0109] Thereafter, the lower wafer W2 is transferred to the bonding device 41 by the transfer device 61. The lower wafer W2 transferred into the bonding device 41 is transferred to the position adjustment mechanism 210 via the transition 200. Then, the horizontal orientation of the lower wafer W2 is adjusted by the position adjustment mechanism 210 (step S108).

[0110] Thereafter, the lower wafer W2 is transferred to the lower chuck 231 and is suction-held by the lower chuck 231 (step S109). The lower wafer W2 is suction-held at its non-bonding surface W2n by the lower chuck 231 with its notch portion facing a predetermined direction.

[0111] Next, the horizontal positions of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are adjusted (step S110).

[0112] Next, the first lower chuck moving part 310 moves the lower chuck 231 vertically upward to adjust the vertical positions of the upper chuck 230 and the lower chuck 231. As a result, the vertical positions of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are adjusted (step S111).

[0113] At this time, the distance between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 is a preset distance, for example, 80 μm to 100 μm.

[0114] Then, a bonding process is performed to bond the upper wafer W1 and the lower wafer W2 with a given gap maintained therebetween (step S112), and the bonding process in the bonding device 41 is completed.

[0115] Fig. 10 is a timing chart showing the operation of each part in the bonding process according to the embodiment. Note that Fig. 10 shows the timing chart from the point in time when the above-mentioned step S110 (adjusting the horizontal positions of the upper wafer W1 and the lower wafer W2) is completed.

[0116] First, from time T11, the control unit 5 controls the gas suction unit 272 to suction the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other.

[0117] Furthermore, from time T11, the control unit 5 repeats the operation of raising the lower chuck 231 from the home position to the bond position and the operation of lowering the lower chuck 231 from the bond position to the home position. That is, from time T11, the control unit 5 expands or contracts the gap between the upper wafer W1 and the lower wafer W2.

[0118] By expanding and contracting the gap between the upper wafer W1 and the lower wafer W2 in this manner, the control unit 5 can efficiently suck the atmosphere between the upper wafer W1 and the lower wafer W2.

[0119] Then, at time T12, a given time after time T11, the control unit 5 stops the gas suction unit 272 and operates the gas discharge unit 273 to discharge low-humidity gas between the upper wafer W1 and the lower wafer W2. This allows the control unit 5 to replace the atmosphere between the upper wafer W1 and the lower wafer W2 with a low-humidity atmosphere.

[0120] Furthermore, the control unit 5 continues the operation of expanding or contracting the gap between the upper wafer W1 and the lower wafer W2 even after time T12, thereby enabling the control unit 5 to efficiently replace the atmosphere between the upper wafer W1 and the lower wafer W2 with a low-humidity atmosphere.

[0121] Next, at time T13 when the humidity between the upper wafer W1 and the lower wafer W2 reaches a given humidity, the control unit 5 stops the gas discharge unit 273 and raises the lower chuck 231 to the bonding position.

[0122] The control unit 5 can obtain information as to whether or not the humidity between the upper wafer W1 and the lower wafer W2 has reached a given humidity level from the sensor unit 276. That is, the control unit 5 terminates the process of expanding or contracting the gap between the upper wafer W1 and the lower wafer W2 based on the detection result of the sensor unit 276.

[0123] Then, at the timing when the lower chuck 231 reaches the bonding position, the control unit 5 lowers the pressing pin 253 of the striker 250. As a result, the striker 250 presses down the center W1c of the upper wafer W1, and presses the center W1c of the upper wafer W1 and the center W2c of the lower wafer W2 together with a given force.

[0124] This initiates bonding between the pressed center W1c of the upper wafer W1 and the center W2c of the lower wafer W2. Specifically, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified in steps S101 and S106, van der Waals forces (intermolecular forces) are first generated between the bonding surfaces W1j and W2j, and the bonding surfaces W1j and W2j are bonded together.

[0125] Furthermore, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are made hydrophilic in steps S102 and S107, respectively, the OH groups between the bonding surfaces W1j and W2j form hydrogen bonds, thereby firmly bonding the bonding surfaces W1j and W2j to each other.

[0126] Thereafter, the bonding region between the upper wafer W1 and the lower wafer W2 expands from the center W1c of the upper wafer W1 and the center W2c of the lower wafer W2 toward the outer periphery. That is, the bonding between the bonding surfaces W1j and W2j due to the van der Waals forces and hydrogen bonds expands sequentially from the centers W1c and W2c toward the outer periphery.

[0127] First, at time T13, the striker 250 presses down the center W1c of the upper wafer W1, thereby separating the upper wafer W1 from the center suction pipe 240a. That is, at time T13, the upper wafer W1 is bonded to the lower wafer W2 at the center of the wafer W.

[0128] Then, as a result of the bonding region gradually expanding toward the outer periphery, the upper wafer W1 is separated from the peripheral suction pipe 240c at time T14. At this point, the bonding region has reached the peripheral portions W1e and W2e of the wafer W, so that the upper wafer W1 and the lower wafer W2 are bonded together over their entire surfaces, forming an overlapped wafer T.

[0129] Next, at time T15, which is a given time after time T14, the control unit 5 lowers the position of the lower chuck 231 from the bond position to the home position. Then, at time T16, the control unit 5 lowers the lower chuck 231 to the home position, thereby enabling the overlapped wafer T, which is suction-held by the lower chuck 231, to be removed from the bonding device 41.

[0130] In the embodiment, the various processes described above can improve the bonding quality of the overlapped wafer T. The reason for this will be described below.

[0131] 11A and 11B are diagrams for explaining the details of the bonding process according to the embodiment. As shown in (a) of Fig. 11, the upper wafer W1 and the lower wafer W2 are arranged to face each other, and then, as shown in (b) of Fig. 11, a low-humidity gas is discharged between the upper wafer W1 and the lower wafer W2 from the gas discharge unit 273.

[0132] As a result, the atmosphere between the upper wafer W1 and the lower wafer W2 is replaced with a low-humidity atmosphere, and as shown in (c) of Figure 11, moisture adsorbed on the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 evaporates.

[0133] In the embodiment, since less moisture is adsorbed onto the bonding surfaces W1j and W2j, the hydrogen bonds at the bonding surfaces W1j and W2j are reduced, and therefore the speed at which the bonding area progresses when bonding the upper wafer W1 and the lower wafer W2 can be slowed down.

[0134] This makes it possible to reduce edge voids that occur in the overlapped wafer T. The reason why such edge voids can be reduced will be explained below.

[0135] When the upper wafer W1 and the lower wafer W2 are bonded together, the central portions W1c and W2c are bonded together by intermolecular forces to form a bonding region, and then a wave (so-called bonding wave) is generated as the bonding region expands toward the peripheral portions W1e and W2e of the wafer W.

[0136] One of the causes of edge voids is thought to be a sudden change in pressure at the peripheral edges W1e and W2e of the wafer W when the bonding wave reaches the peripheral edges W1e and W2e of the wafer W.

[0137] This is because such a sudden pressure fluctuation causes the ambient temperature near the peripheral portions W1e and W2e to drop suddenly, causing condensation to occur on the peripheral portion W1e of the upper wafer W1 and the peripheral portion W2e of the lower wafer W2, and edge voids are formed due to this condensation.

[0138] On the other hand, in the embodiment, the speed of progress of the bonding area when bonding the upper wafer W1 and the lower wafer W2 is slowed down, thereby suppressing sudden pressure fluctuations near the peripheral portions W1e and W2e of the wafer W.

[0139] This allows the control unit 5 to prevent a sudden drop in temperature at the peripheral portions W1e and W2e of the wafer W, thereby preventing condensation from occurring at the peripheral portions W1e of the upper wafer W1 and the peripheral portions W2e of the lower wafer W2.

[0140] Therefore, according to the embodiment, edge voids occurring in the overlapped wafer T can be reduced, and the bonding quality of the overlapped wafer T can be improved.

[0141] In addition, in the embodiment, prior to the process of discharging low-humidity gas between the upper wafer W1 and the lower wafer W2 by the gas discharge unit 273, it is preferable to suction the atmosphere between the upper wafer W1 and the lower wafer W2 by the gas suction unit 272.

[0142] This allows the control unit 5 to efficiently introduce low-humidity gas into the gap between the upper wafer W1 and the lower wafer W2, which is relatively narrow and where replacement with low-humidity gas is difficult to progress as is.

[0143] Therefore, according to the embodiment, the overall time required for the bonding process can be shortened, and the overlapped wafer T can be manufactured efficiently.

[0144] In addition, in an embodiment, when the lower wafer W2 held by the lower chuck 231 is located at the home position, the upper wafer W1 and the lower wafer W2 may be sealed from the outside by a sealing portion 275 made of an elastically deformable material.

[0145] This allows the control unit 5 to create a negative pressure in the gap between the upper wafer W1 and the lower wafer W2 when the gas suction unit 272 sucks the atmosphere between the upper wafer W1 and the lower wafer W2. That is, the control unit 5 can more efficiently introduce the low-humidity gas into the gap between the upper wafer W1 and the lower wafer W2, which is relatively narrow.

[0146] Therefore, according to the embodiment, the overall time for the bonding process can be further shortened, and the overlapped wafer T can be manufactured more efficiently.

[0147] In addition, in an embodiment, when the suction and discharge mechanism 270 sucks in the atmosphere between the upper wafer W1 and the lower wafer W2 or discharges gas between the upper wafer W1 and the lower wafer W2, it is preferable to expand or contract the gap between the upper wafer W1 and the lower wafer W2.

[0148] This allows the control unit 5 to obtain a pumping effect that circulates the atmosphere between the upper wafer W1 and the lower wafer W2, thereby enabling more efficient injection of low-humidity gas into the gap between the upper wafer W1 and the lower wafer W2, which is relatively narrow.

[0149] Therefore, according to the embodiment, the overall time for the bonding process can be further shortened, and the overlapped wafer T can be manufactured more efficiently.

[0150] In the above embodiment, the control unit 5 performs a process to expand or contract the gap between the upper wafer W1 and the lower wafer W2 for the entire period from time T11 to time T13, but this expansion or contraction process does not necessarily have to be performed for the entire period from time T11 to time T13.

[0151] For example, the control unit 5 may perform a process of increasing or decreasing the distance between the upper wafer W1 and the lower wafer W2 during a part of the period from time T11 to time T13. For example, the control unit 5 may perform a process of increasing or decreasing the distance between the upper wafer W1 and the lower wafer W2 during the period from time T11 to time T12, or may perform a process of increasing or decreasing the distance between the upper wafer W1 and the lower wafer W2 during the period from time T12 to time T13.

[0152] Furthermore, the control unit 5 does not need to perform the process of increasing or decreasing the gap between the upper wafer W1 and the lower wafer W2 during the period from time T11 to time T13.

[0153] In the above case, during the period when the expansion / contraction process is not performed, the control unit 5 may operate the suction / discharge mechanism 270 while maintaining the position of the lower chuck 231 at the home position.

[0154] This allows the gap between the upper wafer W1 and the lower wafer W2 to be wider than when the lower chuck 231 is positioned at the bond position, so that replacement with low-humidity gas can be promoted even if this expansion / contraction process is not performed.

[0155] Furthermore, in the above embodiment, the striker 250 performs the pressing process on the upper wafer W1 based on the humidity information between the upper wafer W1 and the lower wafer W2 obtained from the sensor unit 276, but the control method of the striker 250 in the embodiment is not limited to this example.

[0156] For example, when the operation time of the suction and discharge mechanism 270 (corresponding to times T11 to T13) reaches a given time, the control unit 5 may determine that the desired low humidity has been reached between the upper wafer W1 and the lower wafer W2, and may perform the pressing process of the upper wafer W1 by the striker 250. The given time may be stored in advance in the storage unit 6.

[0157] In addition, in the above embodiment, an example is shown in which a low-humidity gas having a lower humidity than the atmosphere inside the processing vessel 190 is discharged from the gas discharge part 273 of the suction and discharge mechanism 270, but a high-humidity gas having a higher humidity than the atmosphere inside the processing vessel 190 may also be discharged from the gas discharge part 273.

[0158] This increases the number of hydrogen bonds at the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 immediately before the bonding process, thereby reducing distortion of the overlapping wafer T, for example.

[0159] That is, in the embodiment, it is preferable that the gas discharge part 273 of the suction and discharge mechanism 270 discharges a gas having a humidity different from that of the atmosphere inside the processing vessel 190 (low humidity gas or high humidity gas).

[0160] This makes it possible to control the state of hydrogen bonding at the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 immediately before the bonding process, thereby improving the bonding quality of the overlapped wafer T in various ways.

[0161] <Modification> Next, a modified example of the embodiment will be described with reference to Figures 12 to 14. Figure 12 is a timing chart showing the operation of each part in the bonding process according to the modified example of the embodiment. Note that Figure 12 shows the timing chart from the point in time when the above-mentioned step S110 (adjusting the horizontal positions of the upper wafer W1 and the lower wafer W2) is completed.

[0162] First, from time T21, the control unit 5 controls the gas suction unit 272 to suck in the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other, and operates the gas discharge unit 273 to discharge low-humidity gas between the upper wafer W1 and the lower wafer W2.

[0163] That is, in this modified example, from time T21, the control unit 5 performs a process of sucking the atmosphere from between the upper wafer W1 and the lower wafer W2 and a process of ejecting low-humidity gas between the upper wafer W1 and the lower wafer W2 in parallel.

[0164] This allows the control unit 5 to more efficiently supply the low-humidity gas into the gap between the upper wafer W1 and the lower wafer W2, which is relatively narrow. Therefore, according to this modification, the overall bonding process time can be further shortened, and the overlapped wafer T can be manufactured more efficiently.

[0165] Furthermore, from time T21, the control unit 5 repeats the operation of raising the lower chuck 231 from the home position to the bond position and the operation of lowering the lower chuck 231 from the bond position to the home position. That is, from time T21, the control unit 5 expands or contracts the gap between the upper wafer W1 and the lower wafer W2.

[0166] By expanding or contracting the gap between the upper wafer W1 and the lower wafer W2 in this manner, the control unit 5 can more efficiently replace the atmosphere between the upper wafer W1 and the lower wafer W2 with low-humidity gas.

[0167] Next, at time T22 when the humidity between the upper wafer W1 and the lower wafer W2 reaches a given humidity, the control unit 5 stops the gas suction unit 272 and the gas discharge unit 273 and raises the lower chuck 231 to the bonding position.

[0168] In addition, when the operating time of the suction and discharge mechanism 270 reaches a given time, the control unit 5 may determine that the desired low humidity has been reached between the upper wafer W1 and the lower wafer W2, and may perform the next process (pressing the upper wafer W1 by the striker 250).

[0169] Then, at the timing when the lower chuck 231 reaches the bonding position, the control unit 5 lowers the pressing pin 253 of the striker 250. As a result, the striker 250 presses down the center W1c of the upper wafer W1, and presses the center W1c of the upper wafer W1 and the center W2c of the lower wafer W2 together with a given force.

[0170] This starts bonding between the pressed center W1c of the upper wafer W1 and the center W2c of the lower wafer W2. The following processes are the same as those in the embodiment, so detailed description will be omitted.

[0171] In this modified example, since the process of sucking in the atmosphere and the process of discharging the low-humidity gas are performed in parallel, it is preferable that the suction port 272a of the gas suction section 272 and the discharge port 273d of the gas discharge section 273 are arranged at a distance from each other.

[0172] This makes it possible to prevent the low-humidity gas discharged from the discharge port 273d from being immediately sucked in through the nearby suction port 272a, preventing the replacement with the low-humidity gas from progressing.

[0173] For example, in a plan view, a plurality of suction ports 272a may be arranged in a group in the circumferential direction, and a plurality of discharge ports 273d may be arranged in a group in the circumferential direction, as shown in Fig. 13. Alternatively, in a plan view, the suction ports 272a and the discharge ports 273d may be arranged alternately in the circumferential direction, as shown in Fig. 14.

[0174] FIG. 13 is a top view showing an example of the arrangement of the gas suction section 272 and the gas discharge section 273 according to a modified example of the embodiment, and FIG. 14 is a top view showing another example of the arrangement of the gas suction section 272 and the gas discharge section 273 according to a modified example of the embodiment.

[0175] This arrangement allows a flow of low-humidity gas to be formed throughout the entire space between the upper wafer W1 and the lower wafer W2, allowing the control unit 5 to more efficiently replace the atmosphere between the upper wafer W1 and the lower wafer W2 with low-humidity gas.

[0176] In the modified example, the arrangement of the suction port 272a and the discharge port 273d is not limited to the examples in FIGS.

[0177] The bonding apparatus 41 according to the embodiment includes a first holding unit (upper chuck 230), a second holding unit (lower chuck 231), a striker 250, a processing vessel 190, a gas discharge unit 273, and a controller 5. The first holding unit (upper chuck 230) suction-holds a first substrate (upper wafer W1) from above. The second holding unit (lower chuck 231) suction-holds a second substrate (lower wafer W2) from below. The striker 250 presses the center W1c of the first substrate (upper wafer W1) from above to bring it into contact with the second substrate (lower wafer W2). The processing vessel 190 accommodates the first holding unit (upper chuck 230), the second holding unit (lower chuck 231), and the striker 250. The gas discharge unit 273 discharges a gas having a humidity different from that of the atmosphere in the processing vessel 190. The controller 5 controls each unit. Furthermore, the control unit 5 discharges gas from the gas discharge unit 273 between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) immediately before the first substrate (upper wafer W1) facing the second substrate (lower wafer W2) is pressed by the striker 250. This can improve the bonding quality of the overlapped wafer T.

[0178] Furthermore, in the bonding apparatus 41 according to the embodiment, the gas discharge unit 273 discharges a low-humidity gas having a lower humidity than the atmosphere in the processing container 190 between the first substrate (upper wafer W1) and the second substrate (lower wafer W2). This can reduce edge voids that occur in the overlapped wafer T.

[0179] Furthermore, in the bonding apparatus 41 according to the embodiment, the control unit 5 expands or contracts the gap between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) immediately before the first substrate (upper wafer W1) facing the second substrate (lower wafer W2) is pressed by the striker 250. This allows the overlapped wafer T to be manufactured more efficiently.

[0180] Furthermore, the bonding apparatus 41 according to the embodiment further includes a sensor unit 276 that detects the humidity of the atmosphere between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) facing each other. Furthermore, the control unit 5 terminates the process of expanding or contracting the gap between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) based on the detection result of the sensor unit 276. This allows the pressing process to be performed after the humidity between the upper wafer W1 and the lower wafer W2 has reached a predetermined humidity level, thereby further improving the bonding quality of the overlapped wafers T.

[0181] Furthermore, in the bonding apparatus 41 according to the embodiment, the control unit 5 discharges gas from the gas discharge unit 273 between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) when the second holding unit (lower chuck 231) is positioned at the bonding position. The bonding position is the position of the second holding unit (lower chuck 231) when the first substrate (upper wafer W1) facing the second substrate (lower wafer W2) is pressed by the striker 250. This makes it possible to reduce edge voids that occur in the overlapped wafer T.

[0182] Moreover, the bonding apparatus 41 according to the embodiment further includes a gas suction unit 272 that suctions the atmosphere between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) facing each other. This allows the overlapped wafer T to be manufactured efficiently.

[0183] Furthermore, in the bonding apparatus 41 according to the embodiment, the control unit 5 causes the gas suction unit 272 to suction the atmosphere between the first substrate (upper wafer W1) and the second substrate (lower wafer W2), and then discharges the gas from the gas discharge unit 273. This allows the overlapped wafer T to be manufactured efficiently.

[0184] Furthermore, in the bonding apparatus 41 according to the embodiment, the control unit 5 discharges gas from the gas discharge unit 273 in parallel with the operation of suctioning the atmosphere between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) by the gas suction unit 272. This allows the overlapped wafer T to be manufactured more efficiently.

[0185] The bonding apparatus 41 according to the embodiment further includes a sensor unit 276 that detects the humidity of the atmosphere between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) facing each other. Based on the detection result of the sensor unit 276, the control unit 5 presses the first substrate (upper wafer W1) facing the second substrate (lower wafer W2) with the striker 250. This allows the pressing process to be performed after the humidity between the upper wafer W1 and the lower wafer W2 reaches a predetermined humidity level, thereby further improving the bonding quality of the overlapped wafers T.

[0186] <Details of the joining process> Next, details of the joining process performed by the joining device 41 according to the embodiment will be described with reference to Fig. 15. Fig. 15 is a flowchart showing the processing procedure of the joining process performed by the joining device 41 according to the embodiment.

[0187] 15 shows a flowchart from the point where step S110 (adjusting the horizontal positions of the upper wafer W1 and the lower wafer W2) shown in FIG. 9 is completed.

[0188] First, the control unit 5 controls the bonding device 41 to move the lower chuck 231 to the home position (step S201). Next, the control unit 5 controls the bonding device 41 to repeat an operation of raising the lower chuck 231 from the home position to the bond position and an operation of lowering the lower chuck 231 from the bond position to the home position. That is, the control unit 5 expands or contracts the gap between the upper wafer W1 and the lower wafer W2 (step S202).

[0189] In parallel with the processing of step S202, the control unit 5 controls the gas suction unit 272 to suction the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other (step S203).

[0190] Next, the control unit 5 controls the gas suction unit 272 to stop suction of the atmosphere between the upper wafer W1 and the lower wafer W2 (step S204), and then controls the gas discharge unit 273 to discharge gas (low-humidity gas or high-humidity gas) between the upper wafer W1 and the lower wafer W2 facing each other (step S205).

[0191] Next, the control unit 5 determines whether or not the humidity between the upper wafer W1 and the lower wafer W2 has reached a predetermined level (step S206). If the humidity between the upper wafer W1 and the lower wafer W2 has not reached the predetermined level (step S206, No), the control unit 5 repeats the process of step S206.

[0192] On the other hand, if the humidity between the upper wafer W1 and the lower wafer W2 has reached a given level (step S206, Yes), the control unit 5 controls the gas discharge unit 273 to stop discharging gas between the upper wafer W1 and the lower wafer W2 (step S207).

[0193] Then, the control unit 5 controls the bonding device 41 to move the lower chuck 231 to the bonding position (step S208). Finally, the control unit 5 presses the center of the upper wafer W1 with the striker 250 (step S209), thereby completing the series of processes.

[0194] The bonding method according to the embodiment includes a first holding step (step S105), a second holding step (step S109), a substrate facing step (step S110), a gas discharge step (step S205), and a pressing step (step S209). In the first holding step (step S105), a first holding unit (upper chuck 230) that suction-holds the first substrate (upper wafer W1) from above is used to suction-hold the first substrate (upper wafer W1) from above. In the second holding step (step S109), a second holding unit (lower chuck 231) that suction-holds the second substrate (lower wafer W2) from below is used to suction-hold the second substrate (lower wafer W2) from below. In the substrate facing process (step S110), a first substrate (upper wafer W1) held by a first holding unit (upper chuck 230) and a second substrate (lower wafer W2) held by a second holding unit (lower chuck 231) are brought face to face with each other. In the gas discharge process (step S205), a gas having a humidity different from that of the atmosphere in the processing vessel 190 accommodating the first holding unit (upper chuck 230) and the second holding unit (lower chuck 231) is discharged between the first substrate (upper wafer W1) and the second substrate (lower wafer W2). In the pressing process (step S209), immediately after the gas discharge process (step S205), the striker 250 presses the center W1c of the first substrate (upper wafer W1) from above. This improves the bonding quality of the overlapped wafer T.

[0195] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0196] 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. [Explanation of symbols]

[0197] 1. Joint System 5. Control section 41 Joining equipment 190 Processing Container 230 Upper chuck (an example of the first holding part) 231 Lower chuck (an example of a second holding part) 250 Striker 270 Suction and discharge mechanism 272 Gas suction section 273 Gas outlet 276 Sensor section W1 Upper wafer (an example of the first substrate) W2 Lower wafer (an example of the second substrate)

Claims

1. a first holding unit that suction-holds the first substrate from above; a second holding portion that suction-holds the second substrate from below; a striker that presses the center of the first substrate from above to bring it into contact with the second substrate; a processing vessel that accommodates the first holding part, the second holding part, and the striker; a gas discharge unit that discharges a gas having a humidity different from that of the atmosphere in the processing chamber between the first substrate and the second substrate facing each other; a gas suction unit that suctions an atmosphere between the first substrate and the second substrate facing each other; Equipped with the gas discharge unit and the gas suction unit are positioned to face each other with respect to the centers of the first substrate and the second substrate in a plan view; a plurality of the gas discharge portions and a plurality of the gas suction portions are provided, In a plan view, the plurality of gas discharge portions are positioned side by side in a group in the circumferential direction, In a plan view, the plurality of gas suction portions are arranged in a group in the circumferential direction. Bonding equipment.

2. A first holding portion that suction-holds the first substrate from above; a second holding portion that suction-holds the second substrate from below; a striker that presses the center of the first substrate from above to bring it into contact with the second substrate; a processing vessel that accommodates the first holding part, the second holding part, and the striker; a gas discharge unit that discharges a gas having a humidity different from that of the atmosphere in the processing chamber between the first substrate and the second substrate facing each other; a gas suction unit that suctions an atmosphere between the first substrate and the second substrate facing each other; Equipped with the gas discharge unit and the gas suction unit are positioned to face each other with respect to the centers of the first substrate and the second substrate in a plan view; The suction port of the gas suction unit faces diagonally downward. Bonding equipment.

3. The gas outlet of the gas outlet portion faces diagonally downward. The joining device according to claim 1 or 2.

4. The gas discharge unit discharges a low-humidity gas having a lower humidity than the atmosphere in the processing chamber between the first substrate and the second substrate. The joining device according to any one of claims 1 to 3.

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