WO2021070624A1

WO2021070624A1 - Bonding device and bonding method

Info

Publication number: WO2021070624A1
Application number: PCT/JP2020/036032
Authority: WO
Inventors: 幸浩若元; 浩史前田; 哲也牧; 克宏飯野; 憲雄和田; 英二眞鍋
Original assignee: 東京エレクトロン株式会社
Priority date: 2019-10-08
Filing date: 2020-09-24
Publication date: 2021-04-15
Also published as: JP7325519B2; JPWO2021070624A1; TW202131385A

Abstract

A bonding device (41) according to an aspect of the present disclosure comprises a first holding part, a second holding part, a gas discharging part (271), a striker (250) and a control unit (5). The first holding part adsorptively holds a first substrate from above. The second holding part adsorptively holds a second substrate from below. The gas discharging part (271) discharges gas. The striker (250) presses a central portion (W1c) of the first substrate from above to bring the central portion (W1c) into contact with the second substrate. The control unit (5) controls each part. According to the bonding device (41), when the spacing between the first substrate held by the first holding part and the second substrate held by the second holding part is caused to reach a predetermined distance, a space (S) is formed around the circumferential edge (W1e) of the first substrate and the circumferential edge (W2e) of the second substrate. In addition, the gas discharging part (271) discharges at least one of condensation suppression gas for suppressing condensation and low-molecular size gas the molecular size of which is small into the space (S).

Description

Joining device and joining method

This disclosure relates to a joining device and a joining method.

Conventionally, as a method of joining substrates such as semiconductor wafers, the surface to which the substrates are bonded is modified, the surface of the modified substrate is made hydrophilic, and the hydrophilic substrates are bonded to each other by van der Waals force and hydrogen bonding. A method of joining by (intermolecular force) is known (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-005058

The present disclosure provides a technique capable of reducing edge voids generated in a bonded substrate.

The joining device according to one aspect of the present disclosure includes a first holding unit, a second holding unit, a gas discharge unit, a striker, and a control unit. The first holding portion sucks and holds the first substrate from above. The second holding portion sucks and holds the second substrate from below. The gas discharge unit discharges gas. The striker presses the central portion of the first substrate from above to bring it into contact with the second substrate. The control unit controls each unit. In the joining device, when the distance between the first substrate held by the first holding portion and the second substrate held by the second holding portion is brought close to a preset distance, the first A space is formed around the peripheral edge of the substrate and the peripheral edge of the second substrate. Further, the gas discharge unit discharges at least one of a dew condensation suppressing gas that suppresses dew condensation and a low molecular size gas having a small molecular size into the space.

According to the present disclosure, edge voids generated in the bonded substrate can be reduced.

FIG. 1 is a schematic plan view showing a configuration of a joining system according to an embodiment. FIG. 2 is a schematic side view 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 the surface modification device according to the 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 configurations 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 void reduction mechanism according to the embodiment. FIG. 9 is a flowchart showing a part of the processing procedure of the processing executed by the joining system according to the embodiment. FIG. 10 is a timing chart showing the operation of each part in the joining process according to the embodiment. FIG. 11 is a block diagram showing a configuration of a void reduction gas supply unit according to the embodiment. FIG. 12 is an enlarged side view showing the configuration of the void reduction mechanism according to the first modification of the embodiment. FIG. 13 is an enlarged side view showing the configuration of the void reduction mechanism according to the second modification of the embodiment. FIG. 14 is a cross-sectional view taken along the line AA in FIG. FIG. 15 is a timing chart showing the operation of each part in the joining process according to the third modification of the embodiment. FIG. 16 is a timing chart showing the operation of each part in the joining process according to the modified example 4 of the embodiment. FIG. 17 is a timing chart showing the operation of each part in the joining process according to the modified example 5 of the embodiment. FIG. 18 is a flowchart showing a processing procedure of a joining process executed by the joining device according to the embodiment. FIG. 19 is a flowchart showing a processing procedure of a joining process executed by the joining device according to the third modification of the embodiment.

Hereinafter, embodiments of the joining apparatus and joining method disclosed in the present application will be described in detail with reference to the attached drawings. The present disclosure is not limited by the embodiments shown below. In addition, it should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the reality. Further, even between the drawings, there may be a portion where the relationship and ratio of the dimensions of the drawings are different from each other.

Conventionally, as a method of joining substrates such as semiconductor wafers, the surface to which the substrates are bonded is modified, the surface of the modified substrate is made hydrophilic, and the hydrophilic substrates are bonded to each other by van der Waals force and hydrogen bonding. A method of joining by (intermolecular force) is known.

On the other hand, when joining hydrophilic substrates to each other, voids (hereinafter referred to as edge voids) may occur at the peripheral edge of the bonded substrates. When such edge voids are generated, the generated portion cannot be used as a product, so that the yield may decrease.

Therefore, it is expected to realize a technology that can overcome the above-mentioned problems and reduce the edge voids generated in the bonded substrate.

<Structure of joining system>
First, the configuration of the joining system 1 according to the embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a schematic plan view showing the configuration of the joining system 1 according to the embodiment, and FIG. 2 is a schematic side view of the same. Further, FIG. 3 is a schematic side view of the upper wafer and the lower wafer according to the embodiment. In each drawing referred to below, in order to make the explanation easy to understand, an orthogonal coordinate system in which the vertical upward direction is the positive direction of the Z axis may be shown.

The bonding system 1 shown in FIG. 1 forms a polymerized wafer T by bonding the first substrate W1 and the second substrate W2.

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

In the following, the first substrate W1 will be referred to as "upper wafer W1" and the second substrate W2 will be referred to as "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. Further, when the upper wafer W1 and the lower wafer W2 are collectively referred to, it may be described as "wafer W".

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

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

The loading / unloading station 2 includes a mounting table 10 and a transport area 20. The mounting table 10 includes a plurality of mounting plates 11. Cassettes C1, C2, and C3 for horizontally accommodating a plurality of (for example, 25) substrates are mounted on each mounting plate 11. For example, the cassette C1 is a cassette containing the upper wafer W1, the cassette C2 is a cassette containing the lower wafer W2, and the cassette C3 is a cassette containing the polymerized wafer T.

The transport area 20 is arranged adjacent to the X-axis positive direction side of the mounting table 10. The 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 the transport path 21.

The transport 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. Then, the transfer device 22 connects the upper wafer W1, the lower wafer W2, and the polymerization wafer T between the cassettes C1 to C3 mounted on the mounting plate 11 and the third processing block G3 of the processing station 3 described later. Perform transportation.

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

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

In the first processing block G1, a surface reforming device 30 for modifying the joint surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 with plasma of the processing gas is arranged. The surface modifier 30 cuts the bond of SiO2 on the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 to form a single-bonded SiO, so that the bonding surface W1j can be easily hydrophilized thereafter. Modify W2j.

In the surface modifier 30, for example, a given processing gas is excited to be turned into plasma and ionized in a reduced pressure atmosphere. Then, by irradiating the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 with the ion of the element contained in the processing gas, the bonding surfaces W1j and W2j are plasma-treated and modified. Details of the surface modification device 30 will be described later.

A surface hydrophilic device 40 and a joining device 41 are arranged in the second processing block G2. The surface hydrophilization device 40 hydrophilizes the joint surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 with pure water, and cleans the joint surfaces W1j and W2j.

In the surface hydrophilization apparatus 40, pure water is supplied onto the upper wafer W1 or the lower wafer W2 while rotating the upper wafer W1 or the lower wafer W2 held by the spin chuck, for example. As a result, the pure water supplied on the upper wafer W1 or the lower wafer W2 diffuses on the bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2, and the bonding surfaces W1j and W2j are hydrophilized.

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

As shown in FIG. 2, the third processing block G3 is provided with the transition (TRS)

devices

50 and 51 of the upper wafer W1, the lower wafer W2 and the polymerization wafer T in two stages in order from the bottom.

Further, as shown in FIG. 1, a transport area 60 is formed in an area surrounded by the first processing block G1, the second processing block G2, and the third processing block G3. A transport device 61 is arranged in the transport region 60. The transport device 61 has, for example, a transport arm that is movable in the vertical direction, the horizontal direction, and around the vertical axis.

The transfer device 61 moves in the transfer area 60, and the upper wafer W1 and the lower wafer are placed on the given devices in the first processing block G1, the second processing block G2, and the third processing block G3 adjacent to the transport area 60. W2 and the polymerized wafer T are conveyed.

Further, the joining system 1 includes a control device 4. The control device 4 controls the operation of the joining system 1. Such a control device 4 is, for example, a computer, and includes a control unit 5 and a storage unit 6. The storage unit 6 stores a program that controls various processes such as a joining process. The control unit 5 controls the operation of the joining system 1 by reading and executing the program stored in the storage unit 6.

Note that such a program may be recorded on a recording medium that can be read by a computer, and may be installed from the recording medium in the storage unit 6 of the control device 4. Recording media that can be read by a computer include, for example, a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

<Structure of surface modifier>
Next, the configuration of the surface modifier 30 will be described with reference to FIG. FIG. 4 is a schematic cross-sectional view showing the configuration of the surface modifier 30.

As shown in FIG. 4, the surface modifier 30 has a processing container 70 whose inside can be sealed. A carry-in outlet 71 for the upper wafer W1 or the lower wafer W2 is formed on the side surface of the processing container 70 on the transport region 60 (see FIG. 1) side, and a gate valve 72 is provided at the carry-in outlet 71.

The stage 80 is arranged inside the processing container 70. The stage 80 is, for example, a lower electrode and is made of a conductive material such as aluminum. Below the stage 80, a plurality of drive units 81 including, for example, a motor are provided. The plurality of drive units 81 raise and lower the stage 80.

An exhaust ring 103 provided with a plurality of baffle holes is arranged between the stage 80 and the inner wall of the processing container 70. The exhaust ring 103 uniformly exhausts the atmosphere inside the processing container 70 from the inside of the processing container 70.

A power feeding rod 104 formed of a conductor is connected to the lower surface of the stage 80. A first high-frequency power supply 106 is connected to the feeding rod 104 via a matching unit 105 including, for example, a blocking capacitor. During plasma processing, a given high frequency voltage is applied to the stage 80 from the first high frequency power supply 106.

The upper electrode 110 is arranged inside the processing container 70. The upper surface of the stage 80 and the lower surface of the upper electrode 110 are arranged parallel to each other and facing each other at a given distance. 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 the ground potential. Since the upper electrode 110 is grounded in this way, damage to the lower surface of the upper electrode 110 can be suppressed during the plasma treatment.

As described above, when the high frequency voltage is applied from the first high frequency power source 106 to the stage 80 which is the lower electrode, plasma is generated inside the processing container 70.

In the embodiment, the stage 80, the feeding rod 104, the matching device 105, the first high frequency power supply 106, the upper electrode 110, and the matching device are examples of a plasma generation mechanism for generating plasma of the processing gas in the processing container 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 communicates with the gas supply source 122 that stores the processing gas and the static elimination gas inside. Further, the gas supply pipe 121 is provided with a supply equipment group 123 including a valve for controlling the flow of the processing gas and the static elimination gas, a flow rate adjusting unit, and the like.

Then, the processing gas and the static elimination gas supplied from the gas supply source 122 are flow-controlled by the supply equipment group 123 and introduced into the hollow portion 120 of the upper electrode 110 via the gas supply pipe 121. As the processing gas, for example, oxygen gas, nitrogen gas, argon gas and the like are used. Further, as the static elimination gas, for example, an inert gas such as nitrogen gas or argon gas is used.

Inside the hollow portion 120, a baffle plate 124 is provided to promote uniform diffusion of the processing gas and the static elimination gas. The baffle plate 124 is provided with a large number of small holes. On the lower surface of the upper electrode 110, a large number of gas outlets 125 for ejecting the processing gas and the static elimination gas from the hollow portion 120 into the processing container 70 are formed.

An intake port 130 is formed in the processing container 70. An intake pipe 132 communicating with a vacuum pump 131 that reduces the atmosphere inside the processing container 70 to a given degree of vacuum is connected to the intake port 130.

The upper surface of the stage 80, that is, the surface facing the upper electrode 110 is a horizontal horizontal plane having 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 the mounting portion 91 of the stage cover 90.

<Structure of joining device>
Next, the configuration of the joining device 41 will be described with reference to FIGS. 5 and 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 joining device 41 has a processing container 190 whose inside can be sealed. A carry-in outlet 191 for the upper wafer W1, a lower wafer W2, and a polymerized wafer T is formed on the side surface of the processing container 190 on the transport region 60 side, and an opening / closing shutter 192 is provided at the carry-in outlet 191.

The inside of the processing container 190 is divided into a transport area T1 and a processing area T2 by an inner wall 193. The above-mentioned carry-in outlet 191 is formed on the side surface of the processing container 190 in the transport region T1. Further, the upper wafer W1, the lower wafer W2, and the carry-in outlet 194 of the polymerized wafer T are also formed on the inner wall 193.

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

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

A position adjusting mechanism 210 for adjusting the horizontal orientation of the upper wafer W1 and the lower wafer W2 is provided on the Y-axis positive direction side of the transport region T1. In such a position adjusting mechanism 210, the positions of the notches of the upper wafer W1 and the lower wafer W2 are detected by a detection unit (not shown) while rotating the upper wafer W1 and the lower wafer W2 which are attracted and held by the holding portion (not shown).

As a result, the position adjusting mechanism 210 adjusts the position of the notch portion to adjust the horizontal orientation of the upper wafer W1 and the lower wafer W2. Further, the transport region T1 is provided with an inversion mechanism 220 that inverts the front and back surfaces of the upper wafer W1.

Further, 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 attracts and holds the upper wafer W1 from above. Further, the lower chuck 231 is provided below the upper chuck 230, and sucks and holds the lower wafer W2 from below. The upper chuck 230 is an example of the first holding portion, and the lower chuck 231 is an example of the second holding portion.

As shown in FIG. 6, the upper chuck 230 is supported by a support member 300 provided on the ceiling surface of the processing container 190. The support member 300 is provided with an upper imaging unit (not shown) that images the joint surface W2j of the lower wafer W2 held by the lower chuck 231. Such an upper imaging unit is provided adjacent to the upper chuck 230.

Further, as shown in FIGS. 5 and 6, the lower chuck 231 is supported by the first lower chuck moving portion 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 later. Further, the first lower chuck moving portion 310 is configured so that the lower chuck 231 can be moved in the vertical direction and can be rotated around the vertical axis.

As shown in FIG. 5, the first lower chuck moving portion 310 is provided with a lower imaging portion (not shown) that images the joint surface W1j of the upper wafer W1 held by the upper chuck 230. Such a lower imaging unit is provided adjacent to the lower chuck 231.

Further, as shown in FIGS. 5 and 6, the first lower chuck moving portion 310 is provided on the lower surface side of the first lower chuck moving portion 310, and a pair of rails 315 extending in the horizontal direction (Y-axis direction). Attached to. The first lower chuck moving portion 310 is configured to be movable along the rail 315.

The pair of rails 315 are provided on the second lower chuck moving portion 316. The second lower chuck moving portion 316 is provided on the lower surface side of the second lower chuck moving portion 316 and is attached to a pair of rails 317 extending in the horizontal direction (X-axis direction).

Then, the second lower chuck moving portion 316 is configured to be movable along the rail 317, that is, to move the lower chuck 231 in the horizontal direction (X-axis direction). The pair of rails 317 are provided on a mounting table 318 provided on the bottom surface of the processing container 190.

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 configurations of the upper chuck 230 and the lower chuck 231 of the joining device 41 according to the embodiment.

The upper chuck 230 has a substantially disk shape, and as shown in FIG. 7, is divided 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 central portion of the upper chuck 230 toward the peripheral edge portion (outer peripheral portion). The regions 230a have a circular shape in a plan view, and the

regions

230b and 230c have an annular shape in a plan view.

As shown in FIG. 7, each

region

230a, 230b, 230c is independently provided with a central suction pipe 240a, an intermediate suction pipe 240b, and a peripheral suction pipe 240c for sucking and holding the upper wafer W1. The intermediate suction pipe 240b is an example of a monitoring unit.

The central suction tube 240a sucks and holds the central portion of the upper wafer W1. The peripheral edge suction pipe 240c sucks and holds the peripheral edge W1e of the upper wafer W1. The intermediate suction tube 240b sucks and holds an intermediate portion between the central portion and the peripheral portion W1e of the upper wafer W1.

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. As described above, the upper chuck 230 is configured so that the evacuation of the upper wafer W1 can be set for each of the

regions

230a, 230b, and 230c.

Further, in the joining device 41, by monitoring the suction state of the suction pipe at each position, it is possible to determine whether or not the upper wafer W1 and the lower wafer W2 are joined at their respective positions. For example, when the vacuum pump 241b is operating and the inside of the intermediate suction pipe 240b changes from negative pressure to atmospheric pressure, it can be considered that the upper wafer W1 is separated from the intermediate suction pipe 240b.

Then, since the upper wafer W1 is separated from the intermediate suction pipe 240b, the control unit 5 can determine that the upper wafer W1 is joined to the lower wafer W2 in the intermediate portion of the wafer W.

A through hole 243 that penetrates the upper chuck 230 in the thickness direction is formed at the center of the upper chuck 230. The central portion of the upper chuck 230 corresponds to the central portion W1c of the upper wafer W1 which is attracted and held by the upper chuck 230. Then, the pressing pin 253 of the striker 250 is inserted into the through hole 243.

The striker 250 is provided on the upper surface of the upper chuck 230, and presses the central portion W1c of the upper wafer W1 with the pressing pin 253. The pressing pin 253 is provided so as to be linearly movable along the vertical axis by the cylinder portion 251 and the actuator portion 252, and presses the opposite substrate (upper wafer W1 in the embodiment) at the tip portion.

Specifically, the pressing pin 253 serves as a starter that first brings the central portion W1c of the upper wafer W1 and the central portion W2c of the lower wafer W2 into contact with each other when the upper wafer W1 and the lower wafer W2, which will be described later, are joined.

The lower chuck 231 has a substantially disk shape, and is divided into a plurality of, for example, two

regions

231a and 231b. These

regions

231a and 231b are provided in this order from the central portion to the peripheral portion 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.

As shown in FIG. 7,

suction tubes

260a and 260b for sucking and holding the lower wafer W2 are independently provided in each of the

regions

231a and 231b.

Different vacuum pumps

261a and 261b are connected to the

suction pipes

260a and 260b, respectively. As described above, the lower chuck 231 is configured so that the evacuation of the lower wafer W2 can be set for each of the

regions

231a and 231b.

On the peripheral edge of the lower chuck 231, stopper members 263 for preventing the upper wafer W1, the lower wafer W2, and the polymerized wafer T from jumping out or sliding down from the lower chuck 231 are provided at a plurality of locations, for example, five locations. ..

Further, the joining device 41 includes a void reduction mechanism 270 that reduces edge voids formed between the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2 facing each other.

The void reduction mechanism 270 has a gas discharge unit 271, a void reduction gas supply unit 272, and a low humidity gas supply unit 273. The gas discharge portion 271 has, for example, an annular shape, and is arranged so as to surround the peripheral edge portion of the upper chuck 230.

The gas discharge unit 271 can selectively discharge the void reduction gas (details will be described later) supplied from the void reduction gas supply unit 272 and the low humidity gas supplied from the low humidity gas supply unit 273.

Further, a plurality of discharge ports 281a (see FIG. 8) are uniformly formed in the gas discharge unit 271 in the circumferential direction (for example, 12 locations at intervals of 30 °). As a result, the void reduction mechanism 270 can discharge the gas substantially evenly in the circumferential direction around the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2 facing each other. The detailed configuration of the gas discharge unit 271 will be described later.

The void reduction gas supply unit 272 supplies, for example, the dew condensation suppressing gas to the gas discharge unit 271. In the embodiment, the dew condensation suppressing gas is, for example, an inert gas such as He gas, Ar gas, or Ne gas, which has a high Joule-Thomson effect and is more effective in suppressing dew condensation than nitrogen gas or oxygen gas contained in the air. Including.

The void reduction gas supply unit 272 includes a gas supply source 272a, a valve 272b, and a flow rate regulator 272c. Then, the dew condensation suppressing gas supplied from the gas supply source 272a is flow-controlled by the valve 272b and the flow rate regulator 272c, and is supplied to the gas discharge unit 271.

Further, in the embodiment, the void reduction gas supply unit 272 may supply the low molecular size gas to the gas discharge unit 271. In the embodiment, the low molecular size gas includes, for example, He gas, H ₂ gas, Ne gas, etc., which have a smaller molecular size than nitrogen gas and oxygen gas contained in air and are easily leaked.

That is, in the embodiment, the void reduction gas supply unit 272 supplies at least one of the dew condensation suppressing gas and the low molecular size gas (collectively referred to as “void reduction gas” in the present disclosure) to the gas discharge unit 271.

The low humidity gas supply unit 273 supplies the low humidity gas to the gas discharge unit 271. In embodiments, the low humidity gas is an inert gas (eg, nitrogen gas) having a humidity below a given humidity.

The low humidity gas supply unit 273 includes a low humidity gas supply source 273a, a valve 273b, and a flow rate regulator 273c. Then, the low humidity gas supplied from the low humidity gas supply source 273a is flow-controlled by the valve 273b and the flow rate regulator 273c, and is supplied to the gas discharge unit 271.

<Structure of void reduction mechanism>
Subsequently, the detailed configuration of the void reduction mechanism 270 will be described with reference to FIG. FIG. 8 is an enlarged side view showing the configuration of the void reduction mechanism 270 according to the embodiment. Note that FIG. 8 shows a case where the distance between the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 is brought close to a preset distance (for example, 80 to 100 μm). It is an enlarged sectional view.

As described above, the void reduction mechanism 270 has a gas discharge unit 271, a void reduction gas supply unit 272, and a low humidity gas supply unit 273. Further, the gas discharge unit 271 has a discharge nozzle 281, a recovery unit 282, a support unit 283, a sealing unit 284, a sensor unit 285, and a substrate constant temperature unit 286.

The discharge nozzle 281 has, for example, an annular shape, and is arranged 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. Further, a plurality of discharge ports 281a are uniformly formed in the discharge nozzle 281 in the circumferential direction.

The recovery unit 282 has, for example, an annular shape, and is arranged above the discharge nozzle 281 so as to cover the gap formed between the peripheral edge of the upper chuck 230 and the discharge nozzle 281. The support portion 283 supports the discharge nozzle 281 and the recovery portion 282 on the upper chuck 230.

The sealing portion 284 has, for example, an annular shape and is attached to the lower surface of the discharge nozzle 281. The sealing portion 284 is made of a material that can be elastically deformed.

Here, in the joining device 41 according to the embodiment, a preset distance (for example, 80 to 100 μm) is provided between the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231. Space S is formed when it is brought close to.

As shown in FIG. 8, such a space S is formed around the peripheral edge portion W1e of the upper wafer W1 and around the peripheral edge portion W2e of the lower wafer W2. Further, the space S is a region separated by an upper chuck 230, a lower chuck 231, a discharge nozzle 281, a collection portion 282, and a sealing portion 284.

Since the sealing portion 284 is elastically deformed in the state shown in FIG. 8, when the upper wafer W1 and the lower wafer W2 are brought close to each other and the sealing portion 284 comes into contact with the lower chuck 231. 284 is not an inhibitory factor.

Then, the gas discharge unit 271 can discharge the void reduction gas or the low humidity gas into the space S from the discharge port 281a formed in the discharge nozzle 281. The effect of discharging the void reduction gas or the low humidity gas into the space S when the distance between the upper wafer W1 and the lower wafer W2 is brought close to a preset distance will be described later.

The sensor unit 285 is provided so as to be in contact with the above-mentioned space S. For example, the sensor unit 285 is provided at a position in contact with the space S in the collection unit 282. The sensor unit 285 includes a temperature sensor, a humidity sensor, an oxygen sensor, a helium sensor, and the like.

The temperature sensor of the sensor unit 285 measures the temperature in the space S, the humidity sensor of the sensor unit 285 measures the humidity in the space S, and the oxygen sensor of the sensor unit 285 measures the oxygen concentration in the space S. The sensor unit 285 is not limited to the case where it is provided in the collection unit 282, and may be provided in the upper chuck 230, the discharge nozzle 281 or the like.

The substrate constant temperature portion 286 is provided so as to be in contact with the peripheral edge portion W2e of the lower wafer W2 in the lower chuck 231. The substrate constant temperature portion 286 holds the temperature of the peripheral edge portion W2e on the lower wafer W2 at a given temperature (for example, room temperature).

A collection flow path 287 is connected to the collection unit 282. The recovery flow path 287 connects the recovery section 282 and the upstream side of the valve 272b in the void reduction gas supply section 272. Further, a valve 288 is provided in the recovery flow path 287.

Then, by controlling the recovery unit 282 and the valve 288, the control unit 5 can recover the void reduction gas in the space S from the space S and return it to the void reduction gas supply unit 272 again.

Further, a vent flow path 289 is connected to the recovery unit 282. The vent flow path 289 connects the recovery unit 282 and an external exhaust treatment facility (not shown). Further, a valve 290 is provided in the vent flow path 289.

Then, the control unit 5 can discharge (vent) the void reduction gas, the low humidity gas, etc. in the space S from the space S to the outside by controlling the recovery unit 282 and the valve 290.

<Processing performed by the joining system>
Subsequently, the details of the processing executed by the joining system 1 according to the embodiment will be described with reference to FIGS. 9 to 11. The various processes shown below are executed based on the control by the control unit 5 of the control device 4.

FIG. 9 is a flowchart showing a part of the processing procedure of the processing executed by the joining 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 mounting plate 11 of the loading / unloading station 2. ..

After that, the upper wafer W1 in the cassette C1 is taken out by the transfer device 22, and is transferred to the transition device 50 of the third processing block G3 of the processing station 3.

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

The ions generated in this way are irradiated on the bonding surface W1j of the upper wafer W1, and the bonding surface W1j is plasma-treated. As a result, a dangling bond of silicon atoms is 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 conveyed to the surface hydrophilic device 40 of the second processing block G2 by the transfer device 61. In the surface hydrophilization apparatus 40, pure water is supplied onto the upper wafer W1 while rotating the upper wafer W1 held by the spin chuck.

Then, the supplied pure water diffuses on the bonding surface W1j of the upper wafer W1. As a result, in the surface modifier 30, the OH group (silanol group) adheres to the dangling bond of the silicon atom on the junction surface W1j of the modified upper wafer W1 to make the junction surface W1j hydrophilic (step). S102). Further, the pure water cleans the bonding surface W1j of the upper wafer W1.

Next, the upper wafer W1 is conveyed to the joining device 41 of the second processing block G2 by the conveying device 61. The upper wafer W1 carried into the joining device 41 is conveyed to the position adjusting mechanism 210 via the transition 200. Then, the position adjusting mechanism 210 adjusts the horizontal orientation of the upper wafer W1 (step S103).

After that, the upper wafer W1 is delivered from the position adjusting mechanism 210 to the reversing mechanism 220. Subsequently, in the transport region T1, the front and back surfaces of the upper wafer W1 are inverted by operating the inversion mechanism 220 (step S104). That is, the bonding surface W1j of the upper wafer W1 is directed downward.

After that, the reversing mechanism 220 rotates and moves below the upper chuck 230. Then, the upper wafer W1 is delivered from the reversing mechanism 220 to the upper chuck 230. The non-bonded surface W1n of the upper wafer W1 is adsorbed and held by the upper chuck 230 (step S105).

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

Next, the lower wafer W2 is conveyed to the surface modifying device 30 by the conveying device 61, and 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.

After that, the lower wafer W2 is conveyed to the surface hydrophilization device 40 by the transfer device 61, and 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.

After that, the lower wafer W2 is conveyed to the joining device 41 by the conveying device 61. The lower wafer W2 carried into the joining device 41 is conveyed to the position adjusting mechanism 210 via the transition 200. Then, the position adjusting mechanism 210 adjusts the horizontal orientation of the lower wafer W2 (step S108).

After that, the lower wafer W2 is conveyed to the lower chuck 231 and is attracted and held by the lower chuck 231 (step S109). The non-bonded surface W2n of the lower wafer W2 is adsorbed and held by the lower chuck 231 in a state where the notch portion is directed in a predetermined direction.

Next, the horizontal position adjustment between the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 is performed (step S110).

Next, the lower chuck 231 is moved vertically upward by the first lower chuck moving unit 310 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).

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 joining process for joining the upper wafer W1 and the lower wafer W2 at a given interval is performed (step S112), and the joining process in the joining device 41 is completed.

FIG. 10 is a timing chart showing the operation of each part in the joining process according to the embodiment. Note that FIG. 10 shows a timing chart from the time when the above-mentioned step S110 (horizontal position adjustment between the upper wafer W1 and the lower wafer W2) is completed.

First, from time T11, the control unit 5 raises the lower chuck 231 from the home position to the bond position to bring the lower wafer W2 closer to the upper wafer W1. Further, the control unit 5 operates the discharge nozzle 281 and the low humidity gas supply unit 273 from the time T11 to discharge the low humidity gas from the discharge nozzle 281 of the gas discharge unit 271.

Further, the control unit 5 controls the recovery unit 282 and the

valves

288 and 290 from the time T11 to discharge the low humidity gas discharged from the atmospheric atmosphere and the discharge nozzle 281 from the vicinity of the lower wafer W2 to the outside (vent). ).

Then, the control unit 5 raises the lower chuck 231 to the bond position at time T12 so that the distance between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 becomes a preset distance. Set the lower wafer W2.

Then, as shown in FIG. 8, a space S is formed around the peripheral edge portion W1e of the upper wafer W1 and around the peripheral edge portion W2e of the lower wafer W2.

As shown in FIG. 10, the gas discharge unit 271 continues to discharge the low humidity gas into the space S even during the time T12 when the space S is formed, and the recovery unit 282 discharges the atmosphere in the space S to the outside. to continue.

As a result, the joining device 41 can maintain the space S, that is, the periphery of the peripheral edge portion W1e of the upper wafer W1 and the periphery of the peripheral edge portion W2e of the lower wafer W2 in a low humidity state.

Next, the control unit 5 lowers the pressing pin 253 of the striker 250 at time T13. As a result, the striker 250 pushes down the central portion W1c of the upper wafer W1 and presses the central portion W1c of the upper wafer W1 and the central portion W2c of the lower wafer W2 with a given force.

As a result, joining is started between the center portion W1c of the pressed upper wafer W1 and the center portion 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 are modified in steps S101 and S106, respectively, first, a van der Waals force (intermolecular) is formed between the bonding surfaces W1j and W2j. Force) is generated, and the joint surfaces W1j and W2j are joined to each other.

Further, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are hydrophilized in steps S102 and S107, respectively, the OH groups between the bonding surfaces W1j and W2j are hydrogen-bonded, and the bonding surfaces W1j and W2j are bonded. They are firmly joined together.

After that, the bonding region between the upper wafer W1 and the lower wafer W2 expands from the central portion W1c of the upper wafer W1 and the central portion W2c of the lower wafer W2 to the outer peripheral portion. That is, the van der Waals force between the above-mentioned bonding surfaces W1j and W2j and the bonding by hydrogen bonding gradually expand from the central portions W1c and W2c toward the outer peripheral portion.

First, at time T13, the upper wafer W1 is separated from the central suction pipe 240a by pushing down the central portion W1c of the upper wafer W1 with the striker 250. That is, at time T13, the upper wafer W1 is joined to the lower wafer W2 at the central portion of the wafer W.

Next, at time T14, the upper wafer W1 is separated from the intermediate suction pipe 240b. That is, at time T14, the upper wafer W1 is joined to the lower wafer W2 at the intermediate portion of the wafer W.

Here, the control unit 5 stops the low humidity gas supply unit 273 and operates the void reduction gas supply unit 272 at the time T14. That is, the control unit 5 switches the gas discharged from the gas discharge unit 271 from the low humidity gas to the void reduction gas at time T14.

Thereby, from the time T14, the space S, that is, the periphery of the peripheral edge portion W1e of the upper wafer W1 and the periphery of the peripheral edge portion W2e of the lower wafer W2 can be made into an atmosphere of void reduction gas.

Then, the control unit 5 controls the recovery unit 282 and the

valves

288 and 290 at the time T15 when a given time elapses from the time T14, so that the atmosphere in the space S is controlled by the void reduction gas via the recovery flow path 287. It is collected in the supply unit 272.

As described above, in the embodiment, the operation of the recovery unit 282 is switched from the vent mode to the recovery mode from the time T15 when a given time has elapsed from the time T14. As a result, from the time when the space S is filled with the void reduction gas, the void reduction gas can be recovered by the recovery unit 282 to the void reduction gas supply unit 272.

Therefore, according to the embodiment, it is possible to suppress the recovery of gas other than the void reduction gas.

After that, the upper wafer W1 is separated from the peripheral suction pipe 240c at the time T16 when the bonding region between the upper wafer W1 and the lower wafer W2 reaches the peripheral portions W1e and W2e. At this point, since the bonding region reaches the peripheral portions W1e and W2e of the wafer W, the upper wafer W1 and the lower wafer W2 are bonded on the entire surface to form the polymerized wafer T.

Then, the control unit 5 stops the void reduction gas supply unit 272 at the time T16. That is, the control unit 5 stops the gas discharge from the gas discharge unit 271 at the time T16. Further, the control unit 5 stops the collection unit 282 at the time T16.

Next, the control unit 5 lowers the position of the lower chuck 231 from the bond position to the home position at the time T17 when a given time has elapsed from the time T16. Then, by lowering the lower chuck 231 to the home position at time T18, the control unit 5 can take out the polymerized wafer T attracted and held by the lower chuck 231 from the joining device 41.

As described above, in the embodiment, before joining the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2, the void reducing gas (for example, dew condensation) surrounds the peripheral edges W1e and W2e. Create an atmosphere of (suppressing gas).

Thereby, according to the embodiment, the edge voids generated in the polymerized wafer T can be reduced. The reason why such edge voids can be reduced will be described below.

When the upper wafer W1 and the lower wafer W2 are bonded, the central portion W1c and the central portion W2c are bonded by an intermolecular force to form a bonding region, and then the bonding region is directed toward the peripheral portions W1e and W2e of the wafer W. Waves (so-called bonding waves) are generated as the wafer expands.

Here, as one of the causes of edge voids, when the bonding wave reaches the peripheral portions W1e and W2e of the wafer W, it is conceivable that a sudden pressure fluctuation occurs at the peripheral portions W1e and W2e of the wafer W. ..

This is because the atmospheric temperature in the vicinity of the peripheral portions W1e and W2e drops sharply due to the sudden fluctuation of the pressure, so that dew condensation occurs on the peripheral portion W1e of the upper wafer W1 and the peripheral portion W2e of the lower wafer W2. This is because edge voids are formed due to the dew condensation.

Therefore, in the embodiment, before the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2 are joined, the dew condensation suppressing gas is applied to the region (that is, the space S) where the dew condensation that causes the edge void is generated. Discharge.

As a result, even if a sudden pressure fluctuation occurs in the vicinity of the peripheral portions W1e and W2e of the wafer W (that is, the space S), it is possible to suppress the temperature of the space S from dropping sharply. Therefore, according to the embodiment, it is possible to suppress the occurrence of dew condensation on the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2.

Further, in the embodiment, before joining the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2, the periphery of the peripheral edges W1e and W2e is also polymerized by creating an atmosphere of a low molecular size gas. The edge voids generated in the wafer T can be reduced.

This is because when an edge void containing a low molecular size gas is formed on the polymerized wafer T, the low molecular size gas having high leakage performance escapes from this edge void, so that the once formed edge void shrinks or disappears. ..

As described above, in the embodiment, before joining the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2, at least one of the dew condensation suppressing gas and the low molecular size gas is surrounded around the peripheral edges W1e and W2e. It is preferable to create an atmosphere of gas (that is, void reduction gas). Thereby, the edge voids generated in the polymerized wafer T can be reduced.

Further, in the embodiment, it is preferable to use a dew condensation suppressing gas and a He gas which is a low molecular size gas as the void reducing gas supplied from the void reducing gas supply unit 272. In this way, by using a He gas having a very high Joule-Thomson effect as the void reducing gas, it is further suppressed that the temperature of the space S suddenly drops even when a sudden pressure fluctuation occurs in the space S. can do.

Furthermore, by using a He gas having a high leak performance as the void reducing gas, the edge void once formed can be efficiently reduced or eliminated. Therefore, according to the embodiment, the generation of edge voids on the polymerized wafer T can be further suppressed.

Further, in the embodiment, after pressing the central portion W1c of the upper wafer W1 with the striker 250, the void reduction gas may be discharged from the gas discharge portion 271 into the space S. As a result, the amount of void-reducing gas used can be reduced, so that the manufacturing cost of the polymerized wafer T can be reduced.

Further, in the embodiment, it is preferable to discharge the low humidity gas from the gas discharge unit 271 to the space S before discharging the dew condensation suppressing gas from the gas discharge unit 271 to the space S. By discharging the low humidity gas into the space S in advance in this way, the space S can be made low humidity even before the dew condensation suppressing gas is discharged, and the amount of the dew condensation suppressing gas used can be further reduced. ..

Therefore, according to the embodiment, it is possible to suppress the edge voids generated in the polymerized wafer T and reduce the manufacturing cost at the same time.

In the embodiment, the low humidity gas may be discharged from the gas discharge unit 271 into the space S before the low molecular size gas is discharged from the gas discharge unit 271 into the space S. As a result, it is possible to prevent the edge voids formed on the polymerized wafer T from containing a large amount of water having a low leak performance.

Therefore, according to the embodiment, the edge voids once formed on the polymerized wafer T can be effectively reduced or eliminated by the low molecular size gas discharged after the low humidity gas.

In this way, when the low humidity gas is discharged in advance, from before the striker 250 presses the central portion W1c of the upper wafer W1 until the upper wafer W1 is joined to the lower wafer W2 in the middle portion of the wafer W. It is preferable to discharge the low humidity gas into the space S.

As a result, the humidity of the space S can be sufficiently low before the void reduction gas is discharged, and a sufficient time can be taken until the space S is replaced with the void reduction gas thereafter. Therefore, according to the embodiment, it is possible to further suppress the generation of edge voids generated in the polymerized wafer T.

When performing the above processing, it is preferable to monitor that the upper wafer W1 is joined to the lower wafer W2 in the intermediate portion of the wafer W by using a monitoring unit such as an intermediate suction pipe 240b. As a result, even when the traveling speed of the bonding region between the upper wafer W1 and the lower wafer W2 varies, the switching process from the low humidity gas to the void reduction gas can be satisfactorily performed.

The monitoring unit that monitors that the upper wafer W1 is joined to the lower wafer W2 in the middle portion of the wafer W is not limited to the suction pipe such as the intermediate suction pipe 240b. For example, by directly observing the bonding state between the upper wafer W1 and the lower wafer W2 using an IR (infrared) camera or the like, it is monitored that the upper wafer W1 is bonded to the lower wafer W2 in the middle portion of the wafer W. be able to.

Further, in the embodiment, the control unit 5 may control the discharge amount of the low humidity gas to the space S based on the humidity information of the space S output from the humidity sensor provided in the sensor unit 285.

As a result, when the space S becomes excessively low humidity, the supply of the low humidity gas to the space S can be suppressed. Therefore, according to the embodiment, the amount of low humidity gas used can be reduced.

Further, in the embodiment, it is preferable to use the recovery unit 282 and the recovery flow path 287 to collect the void reduction gas discharged into the space S to the void reduction gas supply unit 272. As a result, the amount of void-reducing gas used can be reduced.

Further, in the embodiment, the control unit 5 may control the discharge amount of the void reduction gas into the space S based on the oxygen concentration information of the space S output from the oxygen sensor provided in the sensor unit 285.

As a result, when the space S is excessively filled with the void reducing gas, the oxygen concentration in the space S is excessively lowered, so that the supply of the void reducing gas to the space S can be suppressed. Therefore, according to the embodiment, the amount of the void reducing gas used can be further reduced.

When an inert gas such as nitrogen gas is used as the low humidity gas, the control unit 5 has a low humidity in the space S based on the oxygen concentration information of the space S output from the oxygen sensor provided in the sensor unit 285. The amount of gas discharged may be controlled.

As a result, when the space S is excessively filled with the inert low-humidity gas, the oxygen concentration in the space S is excessively lowered, so that the supply of the low-humidity gas to the space S can be suppressed. Therefore, according to the embodiment, the amount of low humidity gas used can be reduced.

Further, in the embodiment, the control unit 5 may control the discharge amount of the void reduction gas into the space S based on the helium concentration information of the space S output from the helium sensor provided in the sensor unit 285.

As a result, when the space S is excessively filled with the void reducing gas, the helium concentration in the space S is excessively increased, so that the supply of the void reducing gas to the space S can be suppressed. Therefore, according to the embodiment, the amount of the void reducing gas used can be further reduced.

Further, in the embodiment, the temperature of the peripheral portion W2e of the lower wafer W2 may be maintained at a given temperature by using the substrate constant temperature portion 286. As a result, even when the bonding wave reaches the peripheral portions W1e and W2e of the wafer W and a sudden pressure fluctuation occurs in the space S, it is possible to suppress the temperature of the space S from dropping sharply.

Therefore, according to the embodiment, the generation of edge voids in the polymerized wafer T can be further suppressed.

In the embodiment, the substrate constant temperature portion 286 is not limited to the case where the temperature of the peripheral edge portion of the lower wafer W2 is maintained at a given temperature, and the substrate constant temperature portion 286 may raise the temperature of the peripheral edge portion W2e of the lower wafer W2. Good.

As a result, even when a sudden pressure fluctuation occurs in the space S, it is possible to further suppress the sudden decrease in the temperature of the space S, so that the generation of edge voids in the polymerized wafer T can be further suppressed. it can.

FIG. 11 is a block diagram showing the configuration of the void reduction gas supply unit 272 according to the embodiment. As shown in FIG. 11, the void reduction gas supply unit 272 includes a gas supply source 272a, a regulator 272d, a gas constant temperature unit 272e, a valve 272b, a flow meter 272f, a flow rate regulator 272c, and a filter 272g from the upstream. And have.

Then, the void reduction gas supplied from the gas supply source 272a is supplied to the gas discharge section 271 of the joining device 41 via the above-mentioned sections.

Here, the void reduction gas supply unit 272 according to the embodiment may have a gas constant temperature unit 272e that keeps the void reduction gas at a constant temperature. For example, as shown in FIG. 11, the constant temperature gas portion 272e is composed of an extended pipe provided inside the joining system 1.

In this way, by providing the extended pipe inside the joining system 1 in which the temperature is kept constant, the temperature of the void reduction gas flowing through the extended pipe is given equal to the inside of the joining system 1. It can be kept at the temperature of (for example, room temperature).

Then, in the embodiment, by keeping the temperature of the void reducing gas (particularly, the dew condensation suppressing gas) constant, the temperature of the space S drops sharply even when a sudden pressure fluctuation occurs in the space S. It can be suppressed. Therefore, according to the embodiment, the generation of edge voids in the polymerized wafer T can be further suppressed.

The gas constant temperature portion 272e is not limited to the case where it is composed of an extended pipe provided inside the joining system 1, and any configuration can be used as long as the temperature of the void reduction gas can be kept constant. There may be.

Further, in the embodiment, the gas constant temperature section 272e is not limited to the case where the temperature of the void reduction gas is maintained at a given temperature, and the gas constant temperature section 272e may raise the temperature of the void reduction gas.

<Various deformation examples>
Subsequently, various modifications of the embodiment will be described with reference to FIGS. 12 to 17. FIG. 12 is an enlarged side view showing the configuration of the void reduction mechanism 270 according to the first modification of the embodiment.

As shown in FIG. 12, the gas discharge unit 271 according to the first modification is composed of a discharge nozzle 281 and a support portion 291.

Further, also in the first modification, when the distance between the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 is brought close to a preset distance (for example, 80 to 100 μm). Space S is formed in.

As shown in FIG. 12, such a space S is formed around the peripheral edge portion W1e of the upper wafer W1 and around the peripheral edge portion W2e of the lower wafer W2. Further, the space S is a region separated by an upper chuck 230, a lower chuck 231 and a discharge nozzle 281 and a support portion 291.

As shown in FIG. 12, the space S formed in the joining device 41 of the modified example 1 is an open space, a gap A1 is formed between the discharge nozzle 281 and the lower chuck 231, and the support portion 291 and the upper chuck 230 are formed. A gap A2 is formed between the two.

However, the space S of the modified example 1 has a recess 292 composed of a discharge nozzle 281 and a support portion 291 at the upper portion. Since the recess 292 has a concave shape facing downward, it is possible to sufficiently hold the void reduction gas, which is lighter than the air discharged into the space S, in the space S.

Thereby, similarly to the above-described embodiment, it is possible to suppress the generation of edge voids formed between the peripheral edge portion W1e of the upper wafer W1 and the peripheral edge portion W2e of the lower wafer W2 in the modified example 1.

Further, in the first modification, as shown in FIG. 12, the discharge port 281a of the discharge nozzle 281 may be directed to the non-bonded surface W1n of the peripheral edge portion W1e of the upper wafer W1. Thereby, when the bonding wave reaching the peripheral portions W1e and W2e of the wafer W is discharged to the outside of the wafer W, it is possible to suppress that the void reduction gas discharged from the discharge nozzle 281 becomes an obstructive factor. ..

Further, in the modified example 1, it is preferable to form a gap A2 between the support portion 291 and the upper chuck 230. As a result, the void reduction gas discharged into the space S can be discharged to the outside through the gap A2.

That is, in the first modification, the concentration of the void reduction gas in the space S can be reset by the time the next joining process starts. Therefore, according to the first modification, the bonding process of the wafer W can be stably performed.

FIG. 13 is an enlarged side view showing the configuration of the void reduction mechanism 270 according to the second modification of the embodiment, and FIG. 14 is a cross-sectional view taken along the line AA in FIG.

As shown in FIGS. 13 and 14, in the second modification, the hole 231d is formed below the space S in the lower chuck 231 and the void reduction gas supply section 272 is connected to the hole 231d. Further, in the second modification, the hole 230d is formed above the space S in the upper chuck 230, and the recovery flow path 287 is connected to the hole 230d.

Then, in the second modification, the void reduction gas is supplied from the void reduction gas supply unit 272 to the space S, and the void reduction gas is recovered from the space S in the recovery flow path 287. As a result, the void reduction gas lighter than air can be efficiently supplied to the space S, and the void reduction gas lighter than air can be efficiently recovered from the space S.

When the void reduction gas is heavier than air, it is preferable to connect the void reduction gas supply unit 272 to the hole 230d and connect the recovery flow path 287 to the hole 231d.

FIG. 15 is a timing chart showing the operation of each part in the joining process according to the third modification of the embodiment. Note that FIG. 15 shows a timing chart from the time when step S110 (horizontal position adjustment between the upper wafer W1 and the lower wafer W2) shown in FIG. 9 is completed.

First, from time T21, the control unit 5 raises the lower chuck 231 from the home position to the bond position to bring the lower wafer W2 closer to the upper wafer W1. Further, the control unit 5 operates the discharge nozzle 281 and the low humidity gas supply unit 273 from the time T21 to discharge the low humidity gas from the discharge nozzle 281 of the gas discharge unit 271.

Further, the control unit 5 controls the recovery unit 282 and the

valves

288 and 290 from the time T21 to discharge the low humidity gas discharged from the atmospheric atmosphere and the discharge nozzle 281 from the vicinity of the lower wafer W2 to the outside (vent). ).

Then, the control unit 5 raises the lower chuck 231 to the bond position at time T22 so that the distance between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 becomes a preset distance. Set the lower wafer W2.

Even during the time T22 when the space S is formed, as shown in FIG. 15, the gas discharge unit 271 continues to discharge the low humidity gas into the space S, and the recovery unit 282 discharges the atmosphere in the space S to the outside. to continue.

Next, the control unit 5 lowers the pressing pin 253 of the striker 250 at time T23. As a result, the striker 250 pushes down the central portion W1c of the upper wafer W1 and presses the central portion W1c of the upper wafer W1 and the central portion W2c of the lower wafer W2 with a given force.

As a result, bonding starts between the center portion W1c of the pressed upper wafer W1 and the center portion 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 are modified in steps S101 and S106 (see FIG. 9), respectively, first, van der between the bonding surfaces W1j and W2j A Waals force is generated, and the joint surfaces W1j and W2j are joined to each other.

Further, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are hydrophilized in steps S102 and S107 (see FIG. 9), respectively, the OH groups between the bonding surfaces W1j and W2j are hydrogen-bonded. The joint surfaces W1j and W2j are firmly joined to each other.

First, at time T23, the upper wafer W1 is separated from the central suction pipe 240a by pushing down the central portion W1c of the upper wafer W1 with the striker 250. That is, at time T23, the upper wafer W1 is joined to the lower wafer W2 at the central portion of the wafer W.

Next, at time T24, the upper wafer W1 is separated from the intermediate suction pipe 240b. That is, at time T24, the upper wafer W1 is bonded to the lower wafer W2 at the intermediate portion of the wafer W.

Here, the control unit 5 stops the low humidity gas supply unit 273 and operates the void reduction gas supply unit 272 at the time T24. That is, the control unit 5 switches the gas discharged from the gas discharge unit 271 from the low humidity gas to the void reduction gas at time T24.

Here, in the modification 3, the control unit 5 controls the flow rate of the void reduction gas discharged from the gas discharge unit 271 to a high flow rate (High). As a result, in the modified example 3, from the time T24, the space S, that is, the periphery of the peripheral edge portion W1e of the upper wafer W1 and the periphery of the peripheral edge portion W2e of the lower wafer W2 can be quickly made into the atmosphere of the void reduction gas.

Then, the control unit 5 changes the flow rate of the void reduction gas discharged from the gas discharge unit 271 from a high flow rate (High) to a low flow rate (Low) (for example, a high flow rate) at a time T25 when a given time has elapsed from the time T24. The flow rate is reduced to about 1/3 of the above.

As a result, the periphery of the peripheral portions W1e and W2e, which quickly became the atmosphere of the void reduction gas, can be maintained in the atmosphere of the void reduction gas, and the amount of the void reduction gas used can be reduced.

After that, the bonding region between the upper wafer W1 and the lower wafer W2 reaches the peripheral portions W1e and W2e, and at the time T26 when the upper wafer W1 and the lower wafer W2 are bonded on the entire surface, the control unit 5 is the void reduction gas supply unit. Stop 272. That is, the control unit 5 stops the gas discharge from the gas discharge unit 271 at the time T26.

At this point, since the bonding region reaches the peripheral edges W1e and W2e of the wafer W, the upper wafer W1 and the lower wafer W2 are bonded on the entire surface to form the polymerized wafer T.

In the third modification, the fact that the bonding region between the upper wafer W1 and the lower wafer W2 reaches the peripheral portions W1e and W2e is an IR camera that directly detects the arrival position of the bonding wave separately provided in the bonding device 41 (FIG. 3). Detected by (not shown).

Then, the control unit 5 recovers the atmosphere in the space S to the void reduction gas supply unit 272 via the recovery flow path 287 by controlling the recovery unit 282 and the

valves

288 and 290 at the time T26.

As described above, in the embodiment, the operation of the recovery unit 282 is switched from the vent mode to the recovery mode from the time T26 when the gas discharge from the gas discharge unit 271 is stopped. As a result, it is possible to suppress the recovery of gas other than the void reduction gas from the space S due to the low discharge amount of the void reduction gas.

Next, the control unit 5 stops the peripheral suction pipe 240c and the recovery unit 282 at the time T27 when a given time has elapsed from the time T26.

Next, the control unit 5 lowers the position of the lower chuck 231 from the bond position to the home position at the time T28 when a given time has elapsed from the time T27. Then, by lowering the lower chuck 231 to the home position at time T29, the control unit 5 can take out the polymerized wafer T attracted and held by the lower chuck 231 from the joining device 41.

As described so far, in the modification 3, the control unit 5 makes the discharge amount of the void reduction gas into the space S variable. As a result, the generation of edge voids can be suppressed, and the amount of void-reducing gas used can be further reduced. Therefore, according to the third modification, it is possible to suppress the edge voids generated in the polymerized wafer T and reduce the manufacturing cost at the same time.

In the example of FIG. 15, the discharge amount of the void reduction gas to the space S is controlled to be gradually reduced, but the discharge amount of the void reduction gas to the space S is not limited to the case of gradually reducing. FIG. 16 is a timing chart showing the operation of each part in the joining process according to the modified example 4 of the embodiment.

As shown in FIG. 16, in the modified example 4, at the time T34, the control unit 5 controls the flow rate of the void reduction gas discharged from the gas discharge unit 271 to a low flow rate (Low). Then, the control unit 5 increases the flow rate of the void reduction gas discharged from the gas discharge unit 271 from a low flow rate (Low) to a high flow rate (High) at a time T35 when a given time has elapsed from the time T34.

As a result, in the modified example 4, a high flow rate is applied at the timing (immediately before the time T36) when the junction region reaches the peripheral portions W1e and W2e, where a high concentration of void reducing gas is most required around the peripheral portions W1e and W2e. The void reduction gas can be supplied to the space S.

Further, in the modified example 4, the void reduction gas is discharged from the gas discharge unit 271 to the space S in advance at a low flow rate prior to the time T36, so that the rise of the gas discharge unit 271 is delayed and the void reduction gas is satisfactorily released. It is possible to suppress the occurrence of the phenomenon of not being discharged.

In the modified example 4 shown in FIG. 16, the processing of the time T31 to the time T34 and the processing of the time T36 to the time T39 is the same as the processing of the time T21 to the time T24 and the time T26 to the time T29 in the above-mentioned modified example 3. Therefore, a detailed description will be omitted.

Further, in the example of FIG. 15 and the example of FIG. 16, an example in which the discharge amount of the void reduction gas into the space S is controlled in two stages (High, Low) is shown, but the discharge amount of the controlled void reduction gas is shown. Is not limited to two stages, and may be controlled in three or more stages.

FIG. 17 is a timing chart showing the operation of each part in the joining process according to the modified example 5 of the embodiment. As shown in FIG. 17, the control unit 5 stops the low humidity gas supply unit 273 and operates the void reduction gas supply unit 272 at time T44. That is, the control unit 5 switches the gas discharged from the gas discharge unit 271 from the low humidity gas to the void reduction gas at time T44.

Then, in the modification 5, from the time T44, the bonding region between the upper wafer W1 and the lower wafer W2 reaches the peripheral edges W1e and W2e, and the time T45 when the upper wafer W1 and the lower wafer W2 are bonded on the entire surface is reached. , The void reduction gas is intermittently discharged from the gas discharge unit 271 into the space S.

This also makes it possible to suppress the generation of edge voids and further reduce the amount of void reduction gas used. Therefore, according to the modified example 5, it is possible to suppress the edge voids generated in the polymerized wafer T and reduce the manufacturing cost at the same time.

In the modified example 5 shown in FIG. 17, the processing of the time T41 to the time T44 and the time T45 to the time T48 is the same as the processing of the time T21 to the time T24 and the time T26 to the time T29 in the above-mentioned modified example 3. Therefore, a detailed description will be omitted.

The joining device 41 according to the embodiment includes a first holding unit (upper chuck 230), a second holding unit (lower chuck 231), a gas discharge unit 271, a striker 250, and a control unit 5. The first holding portion (upper chuck 230) sucks and holds the first substrate (upper wafer W1) from above. The second holding portion (lower chuck 231) sucks and holds the second substrate (lower wafer W2) from below. The gas discharge unit 271 discharges gas. The striker 250 presses the central portion W1c of the first substrate (upper wafer W1) from above to bring it into contact with the second substrate (lower wafer W2). The control unit 5 controls each unit. In the joining device 41, when the distance between the first substrate held by the first holding portion and the second substrate held by the second holding portion is brought close to a preset distance, the peripheral portion of the first substrate A space S is formed around W1e and the peripheral edge portion W2e of the second substrate. Further, the gas discharge unit 271 discharges at least one gas (void reduction gas) of the dew condensation suppressing gas that suppresses dew condensation and the low molecular size gas having a small molecular size into the space S. Thereby, the edge voids generated in the bonded polymerized wafer T can be reduced.

Further, in the joining device 41 according to the embodiment, the control unit 5 presses the central portion W1c of the first substrate (upper wafer W1) with the striker 250, and then the dew condensation suppressing gas and the low molecular size gas are released from the gas discharge unit 271. At least one gas (void reduction gas) is discharged into the space S. As a result, the amount of void-reducing gas used can be reduced, so that the manufacturing cost of the polymerized wafer T can be reduced.

Further, in the joining device 41 according to the embodiment, the gas discharge unit 271 discharges a low humidity gas into the space S. As a result, it is possible to suppress edge voids generated in the polymerized wafer T and reduce the manufacturing cost at the same time.

Further, the joining device 41 according to the embodiment includes a humidity sensor that measures the humidity of the space S. Then, the control unit 5 controls the discharge amount of the low humidity gas to the space S based on the humidity information of the space S output from the humidity sensor. As a result, the amount of low humidity gas used can be reduced.

Further, in the joining device 41 according to the embodiment, in the control unit 5, the gas discharge unit 271 is a dew condensation suppressing gas and a low molecular size gas before the striker 250 presses the central portion W1c of the first substrate (upper wafer W1). The low-humidity gas is discharged from the gas discharge unit 271 into the space S until at least one of the gases (void-reducing gas) is discharged into the space S. As a result, it is possible to suppress edge voids generated in the polymerized wafer T and reduce the manufacturing cost at the same time.

Further, the joining device 41 according to the embodiment has a first substrate (upper wafer W1) and a second substrate (lower wafer W2) in an intermediate portion between the central portion W1c and the peripheral portion W1e of the first substrate (upper wafer W1). ) Is provided with a monitoring unit (intermediate suction pipe 240b) for monitoring the contact state. Then, the control unit 5 sets the gas discharged into the space S from the low humidity gas to at least one of the dew condensation suppressing gas and the low molecular size gas based on the information output from the monitoring unit (intermediate suction pipe 240b). Switch to (void reduction gas). As a result, even when the traveling speed of the bonding region between the upper wafer W1 and the lower wafer W2 varies, the switching process from the low humidity gas to the void reduction gas can be satisfactorily performed.

Further, the joining device 41 according to the embodiment includes a recovery unit 282 that recovers at least one gas (void reduction gas) of the dew condensation suppressing gas and the low molecular weight gas discharged into the space S from the space S. As a result, the amount of void-reducing gas used can be reduced.

Further, the joining device 41 according to the embodiment includes an oxygen sensor for measuring the oxygen concentration in the space S. Then, the control unit 5 controls the recovery operation of at least one of the dew condensation suppressing gas and the low molecular weight gas (void reduction gas) by the recovery unit 282 based on the oxygen concentration information of the space S output from the oxygen sensor. To do. As a result, the amount of void-reducing gas used can be further reduced.

Further, the joining device 41 according to the embodiment includes a substrate constant temperature portion 286 that keeps the peripheral portion W2e of the second substrate (lower wafer W2) at a constant temperature. As a result, the generation of edge voids on the polymerized wafer T can be further suppressed.

Further, the joining device 41 according to the embodiment includes a gas constant temperature section 272e that keeps at least one gas (void reduction gas) of the dew condensation suppressing gas and the low molecular size gas at a constant temperature. As a result, the generation of edge voids on the polymerized wafer T can be further suppressed.

Further, in the joining device 41 according to the embodiment, the control unit 5 makes the discharge amount of at least one gas (void reduction gas) of the dew condensation suppressing gas and the low molecular size gas into the space S variable. As a result, it is possible to suppress edge voids generated in the polymerized wafer T and reduce the manufacturing cost at the same time.

Further, in the joining device 41 according to the embodiment, the control unit 5 gradually reduces the discharge amount of at least one gas (void reduction gas) of the dew condensation suppressing gas and the low molecular size gas into the space S. As a result, the periphery of the peripheral portions W1e and W2e, which quickly become the atmosphere of the void reduction gas, can be maintained in the atmosphere of the void reduction gas, and the amount of the void reduction gas used can be reduced.

Further, in the joining device 41 according to the embodiment, the dew condensation suppressing gas includes at least one gas among He gas, Ar gas and Ne gas. As a result, even when a sudden pressure fluctuation occurs in the vicinity of the peripheral portions W1e and W2e of the wafer W, it is possible to suppress the temperature of the space S from dropping sharply.

Further, in the joining device 41 according to the embodiment, the low molecular weight gas contains _{at least one of He gas, H 2} gas, and Ne gas. As a result, even if an edge void is once formed on the polymerized wafer T, the edge void can be reduced or eliminated.

<Details of joining process>
Subsequently, with reference to FIGS. 18 and 19, details of the joining process executed by the joining device 41 according to the embodiment and the third modification will be described. FIG. 18 is a flowchart showing a processing procedure of the joining process executed by the joining device 41 according to the embodiment.

Note that FIG. 18 shows a flowchart from the time when step S110 (horizontal position adjustment between the upper wafer W1 and the lower wafer W2) shown in FIG. 9 is completed.

First, the control unit 5 controls the gas discharge unit 271 and the low humidity gas supply unit 273 to discharge the low humidity gas from the discharge nozzle 281 of the gas discharge unit 271 (step S201). Then, the control unit 5 controls the recovery unit 282 and the

valves

288 and 290 to discharge the low humidity gas discharged from the atmospheric atmosphere and the discharge nozzle 281 to the outside (step S202).

Next, the control unit 5 controls the upper chuck 230 and the lower chuck 231 to preset between the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231. Get closer to the distance.

As a result, the control unit 5 forms a space S around the peripheral edge portion W1e of the upper wafer W1 and around the peripheral edge portion W2e of the lower wafer W2 (step S203).

Next, the control unit 5 presses the central portion of the upper wafer W1 with the striker 250 (step S204). Then, the control unit 5 determines whether or not the intermediate portion of the wafer W is joined (step S205).

Here, when the intermediate portion of the wafer W is not joined (steps S205 and No), the process of step S205 is repeated. On the other hand, when the intermediate portion of the wafer W is joined (step S205, Yes), the control unit 5 stops the discharge of the low humidity gas from the gas discharge unit 271 and discharges the void reduction gas from the gas discharge unit 271. Discharge (step S206).

Next, the control unit 5 controls the recovery unit 282 and the

valves

288 and 290 after a lapse of a given time from the start of discharging the dew condensation suppression void reduction gas from the gas discharge unit 271, and voids from the space S. The reduced gas is recovered (step S207).

Next, the control unit 5 determines whether or not the peripheral edge portion of the wafer W is joined (step S208). Here, when the peripheral edge portion of the wafer W is not joined (steps S208 and No), the process of step S208 is repeated.

On the other hand, when the peripheral edges of the wafer W are joined (steps S208, Yes), the control unit 5 stops the discharge of the void reduction gas from the gas discharge unit 271 and the void reduction gas from the recovery unit 282. The collection is stopped (step S209), and a series of processes is completed.

FIG. 19 is a flowchart showing a processing procedure of the joining process executed by the joining device 41 according to the third modification of the embodiment. Note that FIG. 19 shows a flowchart from the time when step S110 (horizontal position adjustment between the upper wafer W1 and the lower wafer W2) shown in FIG. 9 is completed.

First, the control unit 5 controls the gas discharge unit 271 and the low humidity gas supply unit 273 to discharge the low humidity gas from the discharge nozzle 281 of the gas discharge unit 271 (step S301). Then, the control unit 5 controls the recovery unit 282 and the

valves

288 and 290 to discharge the low humidity gas discharged from the atmospheric atmosphere and the discharge nozzle 281 to the outside (step S302).

As a result, the control unit 5 forms a space S around the peripheral edge portion W1e of the upper wafer W1 and around the peripheral edge portion W2e of the lower wafer W2 (step S303).

Next, the control unit 5 presses the central portion of the upper wafer W1 with the striker 250 (step S304). Then, the control unit 5 determines whether or not the intermediate portion of the wafer W is joined (step S305).

Here, when the intermediate portion of the wafer W is not joined (step S305, No), the process of step S305 is repeated. On the other hand, when the intermediate portion of the wafer W is joined (step S305, Yes), the control unit 5 stops the discharge of the low humidity gas from the gas discharge unit 271 and changes the discharge amount of the void reduction gas. Is discharged from the gas discharge unit 271 (step S306).

Next, the control unit 5 directly detects the arrival position of the bonding wave to determine whether or not the peripheral edge portion of the wafer W has been bonded (step S307). Here, when the peripheral edge portion of the wafer W is not bonded (step S307, No), the process of step S307 is repeated.

On the other hand, when the peripheral edge portion of the wafer W is joined (step S307, Yes), the control unit 5 stops the discharge of the void reduction gas from the gas discharge unit 271 (step S308). Then, the control unit 5 controls the recovery unit 282 and the

valves

288 and 290 to recover the void reduction gas from the space S (step S309).

Next, the control unit 5 stops the recovery of the void reduction gas from the space S after a lapse of a given time from the start of the recovery of the void reduction gas from the space S (step S310), and a series of series. End the process.

The joining method according to the embodiment includes a first holding step (step S105), a second holding step (step S109), a space forming step (steps S203 and S303), and a void reduction gas discharge step (steps S206 and S306). And include. In the first holding step (step S105), the first substrate (upper wafer W1) is sucked and held from above by using the first holding portion (upper chuck 230) that sucks and holds the first substrate (upper wafer W1) from above. .. In the second holding step (step S109), the second substrate (lower wafer W2) is sucked and held from below by using the second holding portion (lower chuck 231) that sucks and holds the second substrate (lower wafer W2) from below. .. In the space forming step (steps S203 and S303), the space forming step (steps S203, S303) brings the distance between the first substrate held by the first holding portion and the second substrate held by the second holding portion close to a preset distance, and causes the first substrate. A space S is formed around the peripheral edge of the second substrate and the peripheral edge of the second substrate. In the void reduction gas discharge step (steps S206 and S306), at least one gas (void reduction gas) of the dew condensation suppressing gas that suppresses dew condensation and the low molecular size gas having a small molecular size is discharged into the space S. Thereby, the edge voids generated in the bonded polymerized wafer T can be reduced.

Further, in the joining method according to the embodiment, the void reduction gas discharge step (step S306) makes the discharge amount of at least one of the dew condensation suppressing gas and the low molecular size gas (void reduction gas) into the space S variable. .. As a result, it is possible to suppress edge voids generated in the polymerized wafer T and reduce the manufacturing cost at the same time.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various changes can be made as long as the purpose is not deviated. For example, in the above-described embodiment, an example in which a He gas having a Joule-Thomson effect and a high leak performance is used as the void reducing gas has been shown, but if the gas has a Joule-Thomson effect or a high leak performance, it is other than the He gas. Gas may be used.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. Indeed, the above embodiments can be embodied in a variety of forms. Further, the above-described embodiment may be omitted, replaced or changed in various forms without departing from the scope of the appended claims and the purpose thereof.

1 Joining system 5 Control unit 41 Joining device 230 Upper chuck (an example of the first holding part)
231 Lower chuck (an example of the second holding part)
240b Intermediate suction pipe (an example of monitoring unit)
250 Striker 270 Void reduction mechanism 271 Gas discharge part 272 Void reduction gas supply part 272e Gas constant temperature part 273 Low humidity gas supply part 282 Recovery part 285 Sensor part 286 Board constant temperature part S Space W1 Upper wafer (example of the first substrate)
W2 lower wafer (an example of the second substrate)
W1c, W2c Central part W1e, W2e Peripheral part

Claims

A first holding part that sucks and holds the first substrate from above,
A second holding part that sucks and holds the second substrate from below,
A gas discharge part that discharges gas and
A striker that presses the central portion of the first substrate from above to bring it into contact with the second substrate.
A control unit that controls each unit and
With
When the distance between the first substrate held by the first holding portion and the second substrate held by the second holding portion is brought close to a preset distance, the peripheral edge portion of the first substrate. And a space is formed around the peripheral edge of the second substrate.
The gas discharge unit is a bonding device that discharges at least one of a dew condensation suppressing gas that suppresses dew condensation and a low molecular size gas having a small molecular size into the space.
According to claim 1, the control unit presses the central portion of the first substrate with the striker, and then discharges at least one of the dew condensation suppressing gas and the low molecular weight gas from the gas discharge unit into the space. The joining device described.
The joining device according to claim 1 or 2, wherein the gas discharge unit discharges a low humidity gas into the space.
A humidity sensor for measuring the humidity of the space is provided.
The joining device according to claim 3, wherein the control unit controls the discharge amount of the low humidity gas into the space based on the humidity information of the space output from the humidity sensor.
The control unit is from before the striker presses the central portion of the first substrate until the gas discharge unit discharges at least one of the dew condensation suppressing gas and the low molecular weight gas into the space. The joining device according to claim 3 or 4, wherein the low humidity gas is discharged from the gas discharge unit into the space.
A monitoring unit for monitoring the contact state between the first substrate and the second substrate in the intermediate portion between the central portion and the peripheral portion of the first substrate is provided.
5. The control unit switches the gas discharged into the space from the low humidity gas to at least one of the dew condensation suppressing gas and the low molecular size gas based on the information output from the monitoring unit. The joining device described in 1.
The joining device according to any one of claims 1 to 6, further comprising a recovery unit that recovers at least one of the dew condensation suppressing gas and the low molecular weight gas discharged into the space.
It is equipped with an oxygen sensor that measures the oxygen concentration in the space.
7. The control unit controls the recovery operation of at least one of the dew condensation suppressing gas and the low molecular weight gas by the recovery unit based on the oxygen concentration information in the space output from the oxygen sensor. The joining device described in 1.
The joining device according to any one of claims 1 to 8, further comprising a substrate constant temperature portion that keeps the peripheral edge portion of the second substrate at a constant temperature.
The joining device according to any one of claims 1 to 9, further comprising a gas constant temperature portion that keeps at least one of the dew condensation suppressing gas and the low molecular weight gas at a constant temperature.
The joining device according to any one of claims 1 to 10, wherein the control unit makes the discharge amount of at least one of the dew condensation suppressing gas and the low molecular size gas into the space variable.
The joining device according to claim 11, wherein the control unit gradually reduces the amount of at least one of the dew condensation suppressing gas and the low molecular size gas discharged into the space.
The joining device according to any one of claims 1 to 12, wherein the dew condensation suppressing gas contains at least one gas among He gas, Ar gas and Ne gas.
The joining apparatus according to any one of claims 1 to 13, wherein the low molecular weight gas contains at least one gas among He gas, H 2 gas and Ne gas.
A first holding step of sucking and holding the first substrate from above using a first holding portion that sucks and holds the first substrate from above.
A second holding step of sucking and holding the second substrate from below using a second holding portion that sucks and holds the second substrate from below.
The peripheral portion of the first substrate and the first substrate are brought close to a preset distance between the first substrate held by the first holding portion and the second substrate held by the second holding portion. 2 Space formation process that forms a space around the peripheral edge of the substrate,
A void reduction gas discharge step of discharging at least one of a dew condensation suppressing gas and a low molecular size gas having a small molecular size into the space.
Joining method including.
The joining method according to claim 15, wherein the void reduction gas discharge step changes the discharge amount of at least one of the dew condensation suppressing gas and the low molecular size gas into the space.