JP7770495B2 - Bonding equipment - Google Patents

Description

The present disclosure relates to an anastomosis device .

A conventional method for bonding substrates such as semiconductor wafers involves modifying the surfaces of the substrates to be bonded, making the modified substrate surfaces hydrophilic, and bonding the hydrophilized substrates together using van der Waals forces and hydrogen bonds (intermolecular forces) (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2017-005058

This disclosure provides technology that can improve the bonding quality of laminated substrates.

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, a gas discharge unit, and a gas suction unit . The first holding unit suction-holds a first substrate from above. The second holding unit suction-holds a second substrate from below. The striker presses the center of the first substrate from above to contact the second substrate. The processing vessel accommodates the first holding unit, the second holding unit, and the striker. The gas discharge unit discharges gas having a humidity different from that of the atmosphere in the processing vessel between the first and second substrates facing each other . The gas suction unit suctions the atmosphere between the first and second substrates facing each other. In addition, in a plan view, the gas discharge unit and the gas suction unit are positioned to face each other with the centers of the first and second substrates as references.

This disclosure makes it possible to improve the bonding quality of laminated substrates.

FIG. 1 is a schematic plan view showing the configuration of a bonding system according to an embodiment. FIG. 2 is a schematic side view showing the configuration of the joining system according to the embodiment. FIG. 3 is a schematic side view of the upper wafer and the lower wafer according to the embodiment. FIG. 4 is a schematic cross-sectional view showing the configuration of a surface modification apparatus according to an embodiment. FIG. 5 is a schematic plan view showing the configuration of the joining device according to the embodiment. FIG. 6 is a schematic side view showing the configuration of the joining device according to the embodiment. 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. FIG. 8 is an enlarged side view showing the configuration of the suction and discharge mechanism according to the embodiment. FIG. 9 is a flowchart illustrating a part of a processing procedure of a process executed by the joint system according to the embodiment. FIG. 10 is a timing chart showing the operation of each unit in the joining process according to the embodiment. FIG. 11 is a diagram for explaining details of the joining process according to the embodiment. FIG. 12 is a timing chart showing the operation of each unit in the joining process according to the modified embodiment. 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. 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. FIG. 15 is a flowchart illustrating the procedure of the joining process executed by the joining device according to the embodiment.

Embodiments of the joining device and joining method disclosed herein will be described in detail below with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from reality. Furthermore, the drawings may include portions where the dimensional relationships and ratios differ from one another.

A conventional method for bonding substrates such as semiconductor wafers involves modifying the surfaces of the substrates to be bonded, making the modified substrate surfaces hydrophilic, and then bonding the hydrophilized substrates together using van der Waals forces and hydrogen bonds (intermolecular forces).

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

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

Therefore, there is a need to develop technology that can overcome the above-mentioned problems and improve the bonding quality of laminated substrates.

<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.

The bonding system 1 shown in Figure 1 forms a laminated wafer T by bonding a first substrate W1 and a second substrate W2.

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. Electronic circuits may also be formed on the second substrate W2.

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." In other words, the upper wafer W1 is an example of a first substrate, and the lower wafer W2 is an example of a second substrate. Furthermore, when referring collectively to the upper wafer W1 and the lower wafer W2, they may be referred to as "wafer W."

Furthermore, hereinafter, as shown in FIG. 3, of the surfaces of the upper wafer W1, the surface that is bonded to the lower wafer W2 will be referred to as the "bonding surface W1j," and the surface opposite the bonding surface W1j will be referred to as the "non-bonding surface W1n." Furthermore, of the surfaces of the lower wafer W2, the surface that is bonded to the upper wafer W1 will be referred to as the "bonding surface W2j," and the surface opposite the bonding surface W2j will be referred to as the "non-bonding surface W2n."

As shown in FIG. 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 the order loading/unloading station 2 and processing station 3. The loading/unloading station 2 and the processing station 3 are also integrally connected.

The loading/unloading station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 includes multiple mounting plates 11. Each mounting plate 11 is loaded with a cassette C1, C2, or C3, which holds multiple substrates (e.g., 25 substrates) in a horizontal position. For example, cassette C1 is a cassette that holds upper wafers W1, cassette C2 is a cassette that holds lower wafers W2, and cassette C3 is a cassette that holds overlapping wafers T.

The transport area 20 is located adjacent to the mounting table 10 on the positive side of the X axis. This transport area 20 is provided with a transport path 21 extending in the Y axis direction and a transport device 22 that can move along this transport path 21.

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

Note that the number of cassettes C1 to C3 placed on the placement plate 11 is not limited to that shown in the figure. Furthermore, in addition to cassettes C1, C2, and C3, cassettes for recovering defective substrates may also be placed on the placement plate 11.

Processing station 3 is equipped with multiple processing blocks, such as three processing blocks G1, G2, and G3, each equipped with various devices. For example, a first processing block G1 is provided on the front side of processing station 3 (negative Y-axis side in Figure 1), and a second processing block G2 is provided on the rear side of processing station 3 (positive Y-axis side in Figure 1). Furthermore, a third processing block G3 is provided on the loading/unloading station 2 side of processing station 3 (negative X-axis side in Figure 1).

The first processing block G1 is equipped 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 from a processing gas. The surface modification device 30 breaks the 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 to make them more susceptible to subsequent hydrophilization.

In the surface modification device 30, for example, a given process gas is excited into 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 device 30 will be described later.

The second processing block G2 is equipped 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, using pure water, and also cleans the bonding surfaces W1j and W2j.

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

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

As shown in FIG. 2, the third processing block G3 is equipped with transition (TRS) devices 50 and 51 for the upper wafer W1, lower wafer W2, and overlapping wafer T, arranged in two stages from bottom to top.

As shown in FIG. 1, a transfer region 60 is formed in the 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 can move, for example, vertically, horizontally, and around a vertical axis.

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

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 memory unit 6. The memory unit 6 stores programs that control 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 memory unit 6.

The program may be recorded on a computer-readable recording medium and installed from that recording medium into the memory 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.

<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.

As shown in FIG. 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 area 60 (see FIG. 1), and a gate valve 72 is provided at the loading/unloading port 71.

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. Below the stage 80, multiple drive units 81, each equipped with a motor, are provided. The multiple drive units 81 raise and lower the stage 80.

An exhaust ring 103 with multiple baffle holes is placed between the stage 80 and the inner wall of the processing vessel 70. The exhaust ring 103 allows the atmosphere inside the processing vessel 70 to be uniformly exhausted from within the processing vessel 70.

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 device 105, which may be a blocking capacitor, for example. During plasma processing, a given high-frequency voltage is applied to the stage 80 from the first high-frequency power supply 106.

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 distance between them. The distance between the upper surface of the stage 80 and the lower surface of the upper electrode 110 is adjusted by the drive unit 81.

The upper electrode 110 is grounded and connected to ground potential. Because the upper electrode 110 is grounded in this way, damage to the underside of the upper electrode 110 during plasma processing can be suppressed.

In this way, a high-frequency voltage is applied from the first high-frequency power supply 106 to the stage 80, which serves as the lower electrode, generating plasma inside the processing vessel 70.

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

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 inside. The gas supply pipe 121 is also provided with a group of supply devices 123, including valves and flow rate regulators that control the flow of the processing gas and the static elimination gas.

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. Examples of processing gases that can be used include oxygen gas, nitrogen gas, and argon gas. Examples of static elimination gases that can be used include inert gases such as nitrogen gas and argon gas.

A baffle plate 124 is provided inside the hollow portion 120 to promote uniform diffusion of the processing gas and static elimination gas. The baffle plate 124 has a large number of small holes. The lower surface of the upper electrode 110 has a large number of gas outlets 125 formed therein, which eject the processing gas and static elimination gas from the hollow portion 120 into the processing vessel 70.

The processing vessel 70 is formed with an intake port 130. The intake port 130 is connected to an intake pipe 132 that communicates with a vacuum pump 131 that reduces the atmosphere inside the processing vessel 70 to a given vacuum level.

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 the diameters of the upper wafer W1 and lower wafer W2. A stage cover 90 is placed on the upper surface of the stage 80, and the upper wafer W1 or lower wafer W2 is placed on the placement portion 91 of the stage cover 90.

<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.

As shown in FIG. 5, the bonding apparatus 41 has a processing vessel 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 of the processing vessel 190 facing the transfer region 60, and an opening/closing shutter 192 is provided at the loading/unloading port 191.

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 of the processing vessel 190 in the transfer region T1. In addition, loading/unloading ports 194 for the upper wafer W1, lower wafer W2, and overlapping wafer T are also formed in the inner wall 193.

The interior of the processing vessel 190 is maintained at a given constant humidity level by a humidity retention mechanism (not shown). This allows the bonding device 18 to perform the bonding process between the upper wafer W1 and the lower wafer W2 in a stable environment.

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

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, lower wafer W2, and overlapping wafer T within the transfer region T1 or between the transfer region T1 and the processing region T2.

A position adjustment mechanism 210 is provided on the positive Y-axis side of the transfer region T1 to adjust the horizontal orientation of the upper wafer W1 and the lower wafer W2. This position adjustment mechanism 210 rotates the upper wafer W1 and the lower wafer W2, which are held by suction on a holding unit (not shown), while detecting the positions of the notches of the upper wafer W1 and the lower wafer W2 with a detection unit (not shown).

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. In addition, an inversion mechanism 220 is provided in the transfer region T1 to invert the front and back surfaces of the upper wafer W1.

Also, as shown in FIG. 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.

As shown in FIG. 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 images the bonding surface W2j of the lower wafer W2 held by the lower chuck 231. This upper imaging unit is provided adjacent to the upper chuck 230.

As shown in Figures 5 and 6, the lower chuck 231 is supported by a first lower chuck moving unit 310 provided below the lower chuck 231. The first lower chuck moving unit 310 moves the lower chuck 231 in the horizontal direction (Y-axis direction), as described below. The first lower chuck moving unit 310 is configured to move the lower chuck 231 vertically and rotate it around a vertical axis.

As shown in FIG. 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. This lower imaging part is provided adjacent to the lower chuck 231.

As shown in Figures 5 and 6, the first lower chuck moving part 310 is attached to a pair of rails 315 that are provided on the underside of the first lower chuck moving part 310 and extend horizontally (in the Y-axis direction). The first lower chuck moving part 310 is configured to be movable along the rails 315.

The pair of rails 315 are 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 underside of the second lower chuck moving part 316 and extend horizontally (in the X-axis direction).

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

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

The upper chuck 230 is generally disk-shaped and, as shown in FIG. 7, is partitioned into multiple, for example, three, regions 230a, 230b, and 230c. These regions 230a, 230b, and 230c are provided in this order from the center of the upper chuck 230 toward its peripheral edge (outer periphery). Region 230a has a circular shape in a plan view, and regions 230b and 230c have annular shapes in a plan view.

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

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 midway between the central portion and the peripheral portion W1e.

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 way, the upper chuck 230 is configured to allow the upper wafer W1 to be vacuumed in each of the regions 230a, 230b, and 230c.

In addition, the bonding device 41 can determine whether the upper wafer W1 and the lower wafer W2 are bonded at each position by monitoring the suction status of the suction pipes at each position. For example, when the vacuum pump 241b is operating and the pressure inside the intermediate suction pipe 240b changes from negative to atmospheric pressure, it can be assumed that the upper wafer W1 has separated from the intermediate suction pipe 240b.

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

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 this upper chuck 230 corresponds to the center W1c of the upper wafer W1, which is held by suction on the upper chuck 230. The pressure pin 253 of the striker 250 is inserted into the through-hole 243.

The striker 250 is mounted on the upper surface of the upper chuck 230 and presses the center W1c of the upper wafer W1 with a pressure pin 253. The pressure pin 253 is movable linearly along a vertical axis by a cylinder portion 251 and an actuator portion 252, and its tip presses against the opposing substrate (in this embodiment, the upper wafer W1).

Specifically, the pressure 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 when bonding the upper wafer W1 and the lower wafer W2, as described below.

The lower chuck 231 is generally disk-shaped and is partitioned into multiple regions, for example, two regions 231a and 231b. These regions 231a and 231b are arranged in this order from the center of the lower chuck 231 toward its periphery. Region 231a has a circular shape in a plan view, and region 231b has an annular shape in a plan view.

As shown in FIG. 7, each region 231a, 231b is provided with an independent suction pipe 260a, 260b for suction-holding the lower wafer W2. A different vacuum pump 261a, 261b is connected to each suction pipe 260a, 260b. In this way, the lower chuck 231 is configured so that the vacuum suction of the lower wafer W2 can be set for each region 231a, 231b.

Stopper members 263 are provided at multiple locations, for example, five locations, around the periphery of the lower chuck 231 to prevent the upper wafer W1, lower wafer W2, and overlapping wafer T from jumping out or sliding off the lower chuck 231.

The bonding device 41 also includes a suction/discharge mechanism 270 that suctions 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.

The suction and discharge mechanism 270 has a main body 271, a gas suction section 272 (see Figure 8), and a gas discharge section 273. The main body 271 has, for example, a circular ring shape and is arranged to surround the periphery of the upper chuck 230.

The gas suction unit 272 sucks the atmosphere between the upper wafer W1 and the lower wafer W2, which face each other. Details of the gas suction unit 272 will be described later.

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

The gas discharge unit 273 has a gas supply source 273a, a valve 273b, a flow regulator 273c, and multiple 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 regulator 273c, and is discharged from the discharge ports 273d.

<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 predetermined distance and the lower chuck 231 is located at the home position.

As described above, the suction and discharge mechanism 270 has a main body 271, a gas suction section 272, and a gas discharge section 273. The suction and discharge mechanism 270 also has a support section 274, a sealing section 275, and a sensor section 276.

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

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

The suction mechanism 272c is, for example, a pump, and is connected to the multiple suction ports 272a via the valve 272b. By operating the valve 272b and the suction mechanism 272c, the control unit 5 can suck the atmosphere between the opposing upper wafer W1 and lower wafer W2 through the multiple suction ports 272a.

The gas discharge section 273 has a gas supply source 273a (see FIG. 7), a valve 273b, a flow rate regulator 273c (see FIG. 7), and multiple discharge ports 273d. The multiple discharge ports 273d are formed on the inner peripheral surface of the main body section 271, evenly spaced in the circumferential direction. In the example of FIG. 8, the discharge ports 273d and the suction port 272a are arranged close to each other.

By operating the valve 273b and the flow rate regulator 273c, the control unit 5 can discharge low-humidity gas from the multiple discharge ports 273d between the upper wafer W1 and the lower wafer W2 facing each other.

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 underside of the main body portion 271. The sealing portion 275 is made of an elastically deformable material.

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.

In other words, when the lower wafer W2 is located in 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.

In addition, because the sealing portion 275 is elastically deformable, when the upper wafer W1 and the lower wafer W2 are brought closer together from the state shown in FIG. 8 and the lower wafer W2 is positioned at the bond position, the sealing portion 275 does not become an obstruction factor.

In this disclosure, the bond position refers to the position of the lower chuck 231 when the striker 250 presses the center W1c of the upper wafer W1. When the lower chuck 231 is in the bond position, the gap between the upper wafer W1 and the lower wafer W2 is, for example, approximately 50 μm.

In addition, in this disclosure, the home position refers to a position where the lower chuck 231 is temporarily placed on standby when the process of placing the lower chuck 231 at the bonding position begins. 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 complete, and the gap between the upper wafer W1 and the lower wafer W2 is, for example, approximately 80 μm to 100 μm.

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 on the upper chuck 230 adjacent to the upper wafer W1. The sensor unit 276 includes a humidity sensor, etc.

By operating the sensor unit 276, the control unit 5 can measure the humidity of the atmosphere between the upper wafer W1 and the lower wafer W2 facing each other.

<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 Figures 9 to 11. Note that the various processes described below are executed based on the control of the control unit 5 of the control device 4.

Figure 9 is a flowchart showing part of the processing procedure executed by the bonding system 1 according to the embodiment. First, a cassette C1 containing multiple upper wafers W1, a cassette C2 containing multiple lower wafers W2, and an empty cassette C3 are placed on a given loading plate 11 of the loading/unloading station 2.

Then, the transfer device 22 removes the upper wafer W1 from the cassette C1 and transfers it to the transition device 50 in 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 in the first processing block G1. At this time, the gate valve 72 is open, and the processing vessel 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.

The ions generated in this manner are irradiated onto the bonding surface W1j of the upper wafer W1, and the bonding surface W1j is plasma-treated. As a result, dangling bonds of silicon atoms are formed on the outermost surface of the bonding surface W1j, and 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 hydrophilization device 40 in the second processing block G2. In the surface hydrophilization device 40, pure water is supplied onto the upper wafer W1 while the upper wafer W1 held on the spin chuck is rotated.

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) adhere 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.

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

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

Then, the inversion mechanism 220 rotates and moves below the upper chuck 230. The upper wafer W1 is then transferred from the inversion mechanism 220 to the upper chuck 230. The upper wafer W1 is held by suction at its non-bonding surface W1n on the upper chuck 230 (step S105).

While the upper wafer W1 is being processed in steps S101 to S105 described above, 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.

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.

Then, 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.

The lower wafer W2 is then transferred to the bonding device 41 by the transfer device 61. After being transferred to the bonding device 41, the lower wafer W2 is transferred to the position adjustment mechanism 210 via the transition 200. The horizontal orientation of the lower wafer W2 is then adjusted by the position adjustment mechanism 210 (step S108).

Then, the lower wafer W2 is transferred to the lower chuck 231 and held by suction on the lower chuck 231 (step S109). The lower wafer W2 is held by suction on its non-bonding surface W2n on the lower chuck 231 with its notch facing in a predetermined direction.

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).

Next, the first lower chuck moving unit 310 moves the lower chuck 231 vertically upward to adjust the vertical positions of the upper chuck 230 and the lower chuck 231. This adjusts 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 (step S111).

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.

Then, a bonding process is performed to bond the upper wafer W1 and the lower wafer W2 while maintaining a given distance between them (step S112), and the bonding process in the bonding device 41 is completed.

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

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.

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. In other words, from time T11, the control unit 5 expands or contracts the gap between the upper wafer W1 and the lower wafer W2.

In this way, by expanding and contracting the gap between the upper wafer W1 and the lower wafer W2, the control unit 5 can efficiently suck in the atmosphere between the upper wafer W1 and the lower wafer W2.

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.

Furthermore, the control unit 5 continues to expand or contract the gap between the upper wafer W1 and the lower wafer W2 even after time T12. This allows the control unit 5 to efficiently replace the atmosphere between the upper wafer W1 and the lower wafer W2 with a low-humidity atmosphere.

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

The control unit 5 can obtain information from the sensor unit 276 as to whether the humidity between the upper wafer W1 and the lower wafer W2 has reached a given humidity level. 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.

Then, when the lower chuck 231 reaches the bonding position, the control unit 5 lowers the pressing pin 253 of the striker 250. This causes the striker 250 to press down the center W1c of the upper wafer W1, pressing the center W1c of the upper wafer W1 and the center W2c of the lower wafer W2 together with a given force.

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

Furthermore, because the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been made hydrophilic in steps S102 and S107, respectively, the OH groups between the bonding surfaces W1j and W2j form hydrogen bonds, firmly bonding the bonding surfaces W1j and W2j together.

Then, the bonding area 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, which is formed by van der Waals forces and hydrogen bonds, expands sequentially from the centers W1c and W2c toward the outer periphery.

First, at time T13, the striker 250 presses down on the center W1c of the upper wafer W1, 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.

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

Next, at time T15, 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 held by suction on the lower chuck 231, to be removed from the bonding device 41.

In this embodiment, the various processes described above can improve the bonding quality of the overlapped wafer T. The reasons for this are explained below.

Figure 11 is a diagram for explaining the details of the bonding process according to the embodiment. As shown in Figure 11(a), the upper wafer W1 and the lower wafer W2 are arranged facing each other, and then, as shown in Figure 11(b), low-humidity gas is discharged from the gas discharge unit 273 between the upper wafer W1 and the lower wafer W2.

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

In this embodiment, less moisture is adsorbed to the bonding surfaces W1j and W2j, which reduces hydrogen bonding at the bonding surfaces W1j and W2j, thereby slowing down the speed at which the bonding region advances when bonding the upper wafer W1 and the lower wafer W2.

As a result, in this embodiment, it is possible to reduce edge voids that occur in the laminated wafer T. The reasons why such edge voids can be reduced are explained below.

When the upper wafer W1 and the lower wafer W2 are bonded, the central portions W1c and W2c are bonded by intermolecular forces to form a bonded region. As the bonded region expands toward the peripheral portions W1e and W2e of the wafer W, waves (so-called bonding waves) are generated.

Here, one of the causes of edge voids is thought to be the sudden pressure fluctuations that occur at the peripheral edges W1e and W2e of the wafer W when the bonding wave reaches these edges W1e and W2e.

This is because such sudden pressure fluctuations cause the ambient temperature near the peripheral portions W1e and W2e to drop suddenly, causing condensation to form on the peripheral portion W1e of the upper wafer W1 and the peripheral portion W2e of the lower wafer W2, resulting in the formation of edge voids.

On the other hand, in this embodiment, the speed of advance of the bonding region when bonding the upper wafer W1 and the lower wafer W2 is slowed down, thereby preventing sudden pressure fluctuations near the peripheral edges W1e and W2e of the wafer W.

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 portion W1e of the upper wafer W1 and the peripheral portion W2e of the lower wafer W2.

Therefore, according to the embodiment, it is possible to reduce edge voids that occur in the overlapped wafer T, thereby improving the bonding quality of the overlapped wafer T.

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

This allows the control unit 5 to efficiently inject 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 would be difficult if left as is.

Therefore, according to the embodiment, the overall bonding process time can be shortened, allowing the laminated wafer T to be manufactured efficiently.

Furthermore, in an embodiment, when the lower wafer W2 held by the lower chuck 231 is located in 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.

As a result, the control unit 5 can create a negative pressure in the gap between the upper wafer W1 and the lower wafer W2 when the gas suction unit 272 suctions the atmosphere between the upper wafer W1 and the lower wafer W2. In other words, the control unit 5 can more efficiently inject low-humidity gas into the relatively narrow gap between the upper wafer W1 and the lower wafer W2.

Therefore, according to the embodiment, the overall bonding process time can be further shortened, allowing the laminated wafer T to be manufactured more efficiently.

In addition, in this embodiment, when the suction/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.

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, allowing for more efficient injection of low-humidity gas into the relatively narrow gap between the upper wafer W1 and the lower wafer W2.

Therefore, according to the embodiment, the overall bonding process time can be further shortened, allowing the laminated wafer T to be manufactured more efficiently.

In the above embodiment, the control unit 5 performs processing 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 processing does not necessarily have to be performed for the entire period from time T11 to time T13.

For example, the control unit 5 may perform a process to expand or contract the gap between the upper wafer W1 and the lower wafer W2 during a portion of the period from time T11 to time T13. For example, the control unit 5 may perform a process to expand or contract the gap between the upper wafer W1 and the lower wafer W2 during the period from time T11 to time T12, or may perform a process to expand or contract the gap between the upper wafer W1 and the lower wafer W2 during the period from time T12 to time T13.

Furthermore, the control unit 5 does not need to perform the process of expanding or contracting the gap between the upper wafer W1 and the lower wafer W2 between time T11 and time T13.

In the above case, during the period when such expansion/contraction processing is not being performed, the control unit 5 may operate the suction/discharge mechanism 270 while maintaining the position of the lower chuck 231 in the home position.

This allows the gap between the upper wafer W1 and the lower wafer W2 to be wider than when the lower chuck 231 is in the bond position, so replacement with low-humidity gas can be carried out even without performing this expansion/contraction process.

In addition, in the above embodiment, the striker 250 performs the pressing process on the upper wafer W1 based on information about the humidity between the upper wafer W1 and the lower wafer W2 obtained from the sensor unit 276, but the method for controlling the striker 250 in the embodiment is not limited to this example.

For example, when the operating 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 a pressing process on the upper wafer W1 using the striker 250. It is preferable that this given time be stored in advance in the memory unit 6.

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 unit 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 unit 273.

This increases the 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 reducing distortion of the overlapping wafer T, for example.

In other words, in this embodiment, it is preferable to discharge a gas (low-humidity gas or high-humidity gas) having a humidity different from that of the atmosphere inside the processing vessel 190 from the gas discharge unit 273 of the suction and discharge mechanism 270.

This allows for various control of the hydrogen bonding state of the bonding surfaces W1j and W2j of the upper wafer W1 and lower wafer W2 immediately before the bonding process, thereby improving the bonding quality of the overlapped wafer T in various ways.

<Modification>
Next, a modified example of the embodiment will be described with reference to Fig. 12 to Fig. 14. Fig. 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 Fig. 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.

First, from time T21, 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, and operates the gas discharge unit 273 to discharge low-humidity gas between the upper wafer W1 and the lower wafer W2.

In other words, in this modified example, from time T21, the control unit 5 concurrently performs a process of sucking the atmosphere from between the upper wafer W1 and the lower wafer W2 and a process of discharging low-humidity gas between the upper wafer W1 and the lower wafer W2.

This allows the control unit 5 to more efficiently inject low-humidity gas into the relatively narrow gap between the upper wafer W1 and the lower wafer W2. Therefore, according to this modified example, the overall bonding process time can be further shortened, allowing the laminated wafer T to be manufactured more efficiently.

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. In other words, from time T21, the control unit 5 expands or contracts the gap between the upper wafer W1 and the lower wafer W2.

In this way, by expanding or contracting the gap between the upper wafer W1 and the lower wafer W2, the control unit 5 can more efficiently replace the atmosphere between the upper wafer W1 and the lower wafer W2 with low-humidity gas.

Next, at time T22 when the humidity between the upper wafer W1 and the lower wafer W2 reaches a predetermined humidity level, 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.

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 with the striker 250).

Then, when the lower chuck 231 reaches the bonding position, the control unit 5 lowers the pressing pin 253 of the striker 250. This causes the striker 250 to press down the center W1c of the upper wafer W1, pressing the center W1c of the upper wafer W1 and the center W2c of the lower wafer W2 together with a given force.

This initiates bonding between the pressed center W1c of the upper wafer W1 and the center W2c of the lower wafer W2. The following process is the same as in the embodiment, so a detailed description will be omitted.

In this modified example, since the process of suctioning 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 unit 272 and the discharge port 273d of the gas discharge unit 273 are positioned apart from each other.

This prevents the low-humidity gas discharged from the discharge port 273d from being immediately sucked in through the nearby suction port 272a, preventing the gas from being replaced with low-humidity gas.

For example, as shown in FIG. 13, in a plan view, multiple suction ports 272a may be arranged in a group in the circumferential direction, and multiple discharge ports 273d may be arranged in a group in the circumferential direction. Alternatively, as shown in FIG. 14, in a plan view, the suction ports 272a and discharge ports 273d may be arranged alternately in the circumferential direction.

Figure 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 embodiment, and Figure 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 embodiment.

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.

In addition, in the modified example, the arrangement of the suction port 272a and the discharge port 273d is not limited to the examples in Figures 13 and 14.

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 control unit 5. The first holding unit (upper chuck 230) suction-holds the first substrate (upper wafer W1) from above. The second holding unit (lower chuck 231) suction-holds the 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 houses 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 with a humidity different from that of the atmosphere inside the processing vessel 190. The control unit 5 controls each component. The control unit 5 also discharges gas from the gas discharge unit 273 between the first substrate (upper wafer W1) and the second substrate (lower wafer W2) just before the first substrate (upper wafer W1) facing the second substrate (lower wafer W2) is pressed by the striker 250. This improves the bonding quality of the overlapped wafer T.

In addition, in the bonding apparatus 41 according to this embodiment, the gas discharge unit 273 discharges a low-humidity gas having a lower humidity than the atmosphere inside the processing vessel 190 between the first substrate (upper wafer W1) and the second substrate (lower wafer W2). This reduces edge voids that occur in the overlapping wafer T.

In addition, 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.

The bonding apparatus 41 according to the embodiment further includes a sensor unit 276 that detects the humidity of the atmosphere between the opposing first substrate (upper wafer W1) and second substrate (lower wafer W2). 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, further improving the bonding quality of the overlapped wafers T.

In addition, 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 in 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 reduces edge voids that occur in the overlapped wafer T.

The bonding apparatus 41 according to this embodiment also 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 for efficient production of the overlapped wafer T.

In addition, in the bonding apparatus 41 according to this 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 gas from the gas discharge unit 273. This allows the overlapped wafer T to be manufactured efficiently.

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

The bonding apparatus 41 according to the embodiment further includes a sensor unit 276 that detects the humidity of the atmosphere between the opposing first substrate (upper wafer W1) and second substrate (lower wafer W2). Based on the detection results of the sensor unit 276, the control unit 5 presses the opposing first substrate (upper wafer W1) against the second substrate (lower wafer W2) using 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, further improving the bonding quality of the overlapped wafers T.

<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.

Note that Figure 15 shows a flowchart from the point at which step S110 (adjusting the horizontal positions of the upper wafer W1 and the lower wafer W2) shown in Figure 9 is completed.

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 repeatedly raise the lower chuck 231 from the home position to the bond position and lower 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).

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).

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). Then, the control unit 5 controls the gas discharge unit 273 to discharge gas (low humidity gas or high humidity gas) between the opposing upper wafer W1 and lower wafer W2 (step S205).

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

On the other hand, if the humidity between the upper wafer W1 and the lower wafer W2 has reached a predetermined 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).

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), completing the series of processes.

The bonding method according to the embodiment includes a first holding process (step S105), a second holding process (step S109), a substrate facing process (step S110), a gas discharge process (step S205), and a pressing process (step S209). The first holding process (step S105) uses a first holding unit (upper chuck 230) that suction-holds the first substrate (upper wafer W1) from above. The second holding process (step S109) uses a second holding unit (lower chuck 231) that suction-holds the second substrate (lower wafer W2) from below. In the substrate facing process (step S110), a first substrate (upper wafer W1) held by the first holding unit (upper chuck 230) and a second substrate (lower wafer W2) held by the second holding unit (lower chuck 231) are brought face to face. In the gas discharge process (step S205), a gas with a humidity different from that of the atmosphere in the processing vessel 190 containing 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 portion W1c of the first substrate (upper wafer W1) from above. This improves the bonding quality of the overlapped wafer T.

The above describes an embodiment of the present disclosure, but the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present disclosure.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in a variety of 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.

REFERENCE SIGNS LIST 1 Bonding system 5 Control unit 41 Bonding device 190 Processing container 230 Upper chuck (an example of a first holding unit)
231 Lower chuck (an example of a second holding portion)
250 striker 270 suction and discharge mechanism 272 gas suction unit 273 gas discharge unit 276 sensor unit W1 upper wafer (an example of a first substrate)
W2: Lower wafer (an example of a second substrate)

Claims (4)

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. 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;
The suction port of the gas suction unit faces diagonally downward.
Bonding equipment. The bonding device according to claim 1 or 2, wherein the gas discharge portion has a discharge port facing obliquely downward. 4. The bonding apparatus according to claim 1, wherein the gas discharge unit discharges a low-humidity gas having a humidity lower than that of an atmosphere in the processing chamber between the first substrate and the second substrate.