JP2015041744A - Joining method and joining system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately join substrates with each other by inhibiting the occurrence of air bubbles in a peripheral part of a space between the substrates.SOLUTION: A joining method according to an embodiment is a joining method of joining substrates with each other by an intermolecular force and includes a surface modification process, a surface hydrophilization process, a gas supply process and a joining process. The surface modification process modifies a surface to be joined of the substrate. The surface hydrophilization process supplies a hydrophilic treatment liquid to the substrate surface modified by the surface modification process to hydrophilize the surface. The gas supply process supplies a gas to the substrate surface hydrophilized by the surface hydrophilization process to reduce the hydrophilic treatment liquid remaining on the surface. The joining process joins the substrates after the gas supply process with each other.

Description

  The disclosed embodiments relate to a bonding method and a bonding system.

  Conventionally, in the manufacturing process of a semiconductor device, a bonding process for bonding two substrates may be performed. For example, when manufacturing a semiconductor device including a back-illuminated image sensor, a bonding process is performed in which a second substrate is bonded to a first substrate on which a semiconductor element such as a photodiode is formed.

  The bonding system that performs the bonding process includes, for example, a surface hydrophilizing device that hydrophilizes the surfaces to which the substrates are bonded, and a bonding device that bonds the substrates whose surfaces are hydrophilized by the surface hydrophilizing device. In such a bonding system, the surface of the substrate is hydrophilized by supplying pure water to the surface of the substrate in the surface hydrophilizing device, and then the substrates are bonded to each other by van der Waals force and hydrogen bond (intermolecular force) in the bonding device. Join (refer to Patent Document 1).

JP2011-187716A

  However, as a result of extensive studies by the inventors, it has been found that when the bonding system described in Patent Document 1 is used, bubbles may be generated at the peripheral edge between the bonded substrates.

  An object of one embodiment of the present invention is to provide a bonding method and a bonding system that can appropriately bond the substrates by suppressing generation of bubbles in the peripheral portion between the substrates.

  The bonding method according to an aspect of the embodiment is a bonding method in which substrates are bonded to each other by intermolecular force, and includes a surface modification step, a surface hydrophilization step, a gas supply step, and a bonding step. In the surface modification step, the surface to be bonded to the substrate is modified. In the surface hydrophilization step, a hydrophilic treatment liquid is supplied to the surface of the substrate modified by the surface modification step to make the surface hydrophilic. In the gas supply process, gas is supplied to the surface of the substrate hydrophilized by the surface hydrophilization process to reduce the hydrophilization treatment liquid remaining on the surface. In the bonding step, the substrates after the gas supply step are bonded to each other.

  According to one aspect of the embodiment, it is possible to appropriately bond the substrates by suppressing generation of bubbles in the peripheral portion between the substrates.

FIG. 1 is a schematic plan view showing the configuration of the joining system according to the present embodiment. FIG. 2 is a schematic side view showing the configuration of the joining system according to the present embodiment. FIG. 3 is a schematic side view of the upper wafer and the lower wafer. FIG. 4 is a schematic side view showing the configuration of the surface modification apparatus. FIG. 5 is a schematic plan view of the lower electrode. FIG. 6 is a schematic side view showing the configuration of the surface hydrophilizing apparatus. FIG. 7 is a schematic plan view showing the configuration of the bonding apparatus. FIG. 8 is a schematic side view showing the configuration of the bonding apparatus. FIG. 9 is a schematic side view showing the configuration of the position adjusting mechanism. FIG. 10 is a schematic plan view showing the configuration of the reversing mechanism. FIG. 11 is a schematic side view showing the configuration of the reversing mechanism. FIG. 12 is a schematic side view showing the configuration of the reversing mechanism. FIG. 13 is a schematic side view illustrating the configuration of the holding arm and the holding member. FIG. 14 is a schematic side view showing the configuration of the upper chuck and the lower chuck. FIG. 15 is a schematic plan view of the upper chuck as viewed from below. FIG. 16 is a schematic plan view of the lower chuck as viewed from above. FIG. 17 is a flowchart illustrating a processing procedure of processing executed by the joining system. FIG. 18A is an operation explanatory diagram of the bonding apparatus. FIG. 18B is an operation explanatory diagram of the bonding apparatus. FIG. 18C is an operation explanatory diagram of the bonding apparatus. FIG. 18D is an operation explanatory diagram of the bonding apparatus. FIG. 18E is an explanatory diagram of the operation of the bonding apparatus. FIG. 18F is an operation explanatory diagram of the bonding apparatus. FIG. 19A is a schematic side view illustrating a configuration of a surface hydrophilizing apparatus according to a first modification. FIG. 19B is a schematic side view showing the configuration of the surface hydrophilizing apparatus according to the second modification.

  Hereinafter, embodiments of a bonding method and a bonding system disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

<1. Structure of joining system>
First, the structure of the joining system which concerns on this embodiment is demonstrated with reference to FIGS. 1-3. FIG. 1 is a schematic plan view showing a configuration of a joining system according to the present embodiment, and FIG. 2 is a schematic side view thereof. FIG. 3 is a schematic side view of the upper wafer and the lower wafer. In the following, in order to clarify the positional relationship, the X-axis direction, the Y-axis direction, and the Z-axis direction that are orthogonal to each other are defined, and the positive direction of the Z-axis is the vertically upward direction.

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

  The substrate W1 is a substrate in which a plurality of electronic circuits are formed on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. The substrate W2 is a bare wafer on which no electronic circuit is formed, for example. The substrate W2 has substantially the same diameter as the substrate W1. Hereinafter, among these substrates W1 and W2, the substrate W1 is described as “upper wafer W1”, and the substrate W2 is described as “lower wafer W2”.

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

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

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

  The conveyance area 20 is arranged adjacent to the X-axis positive direction side of the mounting table 10. In the transport region 20, a transport path 21 extending in the Y-axis direction and a transport device 22 movable along the transport path 21 are provided. The transfer device 22 is also movable in the X-axis direction and can be swung around the Z-axis, and includes a cassette C1 to C3 mounted on the mounting plate 11 and a third processing block G3 of the processing station 3 described later. In the meantime, the upper wafer W1, the lower wafer W2, and the superposed wafer T are transported.

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

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

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

  In the second processing block G2, a surface hydrophilizing device 40 and a joining device 41 are arranged. The surface hydrophilizing device 40 hydrophilizes the bonding surfaces W1j and W2j by supplying a hydrophilic treatment liquid such as pure water to the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2. The bonding apparatus 41 bonds the upper wafer W1 and the lower wafer W2.

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

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

<2. Structure of surface modification device>
Next, the configuration of the surface modification device 30 described above will be described with reference to FIGS. 4 and 5. FIG. 4 is a schematic side view showing the configuration of the surface modification device 30. FIG. 5 is a schematic plan view of the lower electrode.

  As shown in FIG. 4, the surface modification device 30 includes a processing container 70 that can be sealed inside. A loading / unloading port 71 for the upper wafer W <b> 1 or the lower wafer W <b> 2 is formed on the side surface of the processing container 70 on the transfer region 60 side, and a gate valve 72 is provided at the loading / unloading port 71.

  A lower electrode 80 for placing the upper wafer W1 or the lower wafer W2 is provided inside the processing container. Lower electrode 80 is made of a conductive material such as aluminum. Below the lower electrode 80, for example, a drive unit 81 including a motor or the like is provided. The drive unit 81 moves the lower electrode 80 up and down.

  A heat medium circulation channel 82 is provided inside the lower electrode 80. A heat medium whose temperature is adjusted to an appropriate temperature by a temperature adjusting means (not shown) is introduced into the heat medium circulation passage 82 via a heat medium introduction pipe 83. The heat medium introduced from the heat medium introduction pipe 83 circulates in the heat medium circulation channel 82, whereby the lower electrode 80 is adjusted to a desired temperature. The heat of the lower electrode 80 is transmitted to the upper wafer W1 or the lower wafer W2 placed on the upper surface of the lower electrode 80, and the upper wafer W1 or the lower wafer W2 is adjusted to a desired temperature.

  The temperature adjustment mechanism for adjusting the temperature of the lower electrode 80 is not limited to the heat medium circulation channel 82, and other mechanisms such as a cooling jacket and a heater can also be used.

  An electrostatic chuck 90 for electrostatically attracting the upper wafer W1 or the lower wafer W2 is provided on the lower electrode 80. The electrostatic chuck 90 has a structure in which a conductive film 93 such as a copper foil is disposed between two films 91 and 92 made of a polymer insulating material such as polyimide resin. The conductive film 93 is connected to a high-voltage power supply 96 via a wiring 94 and a filter 95 such as a coil. At the time of the plasma processing, a high voltage set to an arbitrary DC voltage is cut from the high voltage power source 96 by the filter 95 and applied to the conductive film 93. Thus, the upper wafer W1 or the lower wafer W2 is electrostatically attracted to the upper surface of the lower electrode 80 (the upper surface of the electrostatic chuck 90) by the Coulomb force generated by the high voltage applied to the conductive film 93.

  On the upper surface of the lower electrode 80, a plurality of heat transfer gas supply holes 100 for supplying a heat transfer gas toward the back surface of the upper wafer W1 or the lower wafer W2 are provided. As shown in FIG. 5, the plurality of heat transfer gas supply holes 100 are uniformly arranged in a plurality of concentric circles on the upper surface of the lower electrode 80.

  As shown in FIG. 4, a heat transfer gas supply pipe 101 is connected to each heat transfer gas supply hole 100. The heat transfer gas supply pipe 101 communicates with a gas supply source (not shown), and a heat transfer gas such as helium from the gas supply source causes the upper surface of the lower electrode 80 and the non-bonded surface of the upper wafer W1 or the lower wafer W2 to pass. It is supplied to a minute space formed between W1n and W2n. Thereby, heat is efficiently transferred from the upper surface of the lower electrode 80 to the upper wafer W1 or the lower wafer W2.

  When heat is transferred to the upper wafer W1 or the lower wafer W2 with sufficient efficiency, the heat transfer gas supply hole 100 and the heat transfer gas supply pipe 101 may be omitted.

  An annular focus ring 102 is disposed around the upper surface of the lower electrode 80 so as to surround the outer periphery of the upper wafer W1 or the lower wafer W2 placed on the upper surface of the lower electrode 80 (see FIG. 5). The focus ring 102 is made of an insulating or conductive material that does not attract reactive ions, and acts so that the reactive ions are effectively incident only on the inner upper wafer W1 or lower wafer W2.

  An exhaust ring 103 having a plurality of baffle holes is disposed between the lower electrode 80 and the inner wall of the processing container 70. By the exhaust ring 103, the atmosphere in the processing container 70 is uniformly exhausted from the processing container 70.

  A power feed rod 104 made of a hollow conductor is connected to the lower surface of the lower electrode 80. A first high-frequency power source 106 is connected to the power feed rod 104 via a matching unit 105 made of, for example, a blocking capacitor. During the plasma processing, a high frequency voltage of 2 MHz, for example, is applied to the lower electrode 80 from the first high frequency power supply 106.

  An upper electrode 110 is disposed above the lower electrode 80. The upper surface of the lower electrode 80 and the lower surface of the upper electrode 110 are arranged in parallel with each other with a predetermined distance therebetween. A distance between the upper surface of the lower electrode 80 and the lower surface of the upper electrode 110 is adjusted by the driving unit 81.

  A second high-frequency power source 112 is connected to the upper electrode 110 via a matching unit 111 made of, for example, a blocking capacitor. During the plasma processing, a high frequency voltage of 60 MHz, for example, is applied from the second high frequency power source 112 to the upper electrode 110. As described above, the high frequency voltage is applied to the lower electrode 80 and the upper electrode 110 from the first high frequency power source 106 and the second high frequency power source 112, thereby generating plasma in the processing container 70.

  A high voltage power supply 96 that applies a high voltage to the conductive film 93 of the electrostatic chuck 90, a first high frequency power supply 106 that applies a high frequency voltage to the lower electrode 80, and a second high frequency power supply that applies a high frequency voltage to the upper electrode 110. 112 is controlled by the control apparatus 300 mentioned later.

  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 a gas supply source 122 that stores processing gas therein. Further, the gas supply pipe 121 is provided with a supply device group 123 including a valve for controlling the flow of the processing gas, a flow rate adjusting unit, and the like. Then, the flow rate of the processing gas supplied from the gas supply source 122 is controlled by the supply device group 123 and is introduced into the hollow portion 120 of the upper electrode 110 via the gas supply pipe 121. For example, oxygen gas, nitrogen gas, argon gas or the like is used as the processing gas.

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

  An intake port 130 is formed below the processing container 70. An intake pipe 132 that communicates with a vacuum pump 131 that depressurizes the atmosphere inside the processing container 70 to a predetermined degree of vacuum is connected to the intake port 130.

  Below the lower electrode 80, raising and lowering pins (not shown) are provided for supporting the upper wafer W1 or the lower wafer W2 from below and raising and lowering them. The elevating pins are configured to be able to protrude from the upper surface of the lower electrode 80 through a through hole (not shown) formed in the lower electrode 80.

<3. Structure of surface hydrophilization device>
Next, the structure of the surface hydrophilization apparatus 40 mentioned above is demonstrated with reference to FIG. FIG. 6 is a schematic side view showing the configuration of the surface hydrophilizing device 40.

  As shown in FIG. 6, the surface hydrophilization device 40 includes a processing container 45, a spin chuck 150, a first supply unit 160, a second supply unit 170, and a cup 180. A loading / unloading port (not shown) for the upper wafer W1 and the lower wafer W2 is formed on the side surface of the processing container 45, and an opening / closing shutter (not shown) is provided at the loading / unloading port.

  A spin chuck 150 is disposed in the center of the processing container 45. The spin chuck 150 includes a holding unit 151, a shaft 152, and a rotation mechanism 153.

  The holding unit 151 sucks and holds the upper wafer W1 or the lower wafer W2 horizontally. The upper wafer W1 or the lower wafer W2 is held by the holding unit 151 so that the bonding surfaces W1j and W2j face upward. As the holding portion 151, for example, a porous chuck can be used.

  Below the holding portion 151, for example, a rotation mechanism 153 provided with a motor or the like is arranged. The rotation mechanism 153 is connected to the holding unit 151 via a shaft 152 extending in the vertical direction, and rotates the holding unit 151 by rotating the shaft 152 about the vertical axis. The shaft 152 is rotatably supported by the processing container 45 and a cup 180 described later via a bearing. The rotating mechanism 153 includes a lifting mechanism source such as a cylinder, for example, and can move the upper wafer W1 or the lower wafer W2 sucked and held by the holding portion 151 up and down.

  Around the spin chuck 150, a cup 180 that receives and collects liquid scattered or dropped from the upper wafer W1 or the lower wafer W2 is disposed. A lower surface of the cup 180 is connected to a discharge pipe 181 that discharges the collected liquid to the outside and an exhaust pipe 182 that exhausts the atmosphere in the cup 180.

  A first supply unit 160 and a second supply unit 170 are disposed outside the cup 180. The first supply unit 160 moves from outside the upper wafer W1 or the lower wafer W2 to above the upper wafer W1 or the lower wafer W2, and supplies the hydrophilic treatment liquid to the upper wafer W1 or the lower wafer W2.

  The first supply unit 160 includes a first nozzle 161, a first arm 162 that horizontally supports the first nozzle 161, and a first turning lift mechanism 163 that turns and lifts the first arm 162.

  A pure water supply source 165 is connected to the first nozzle 161 via a valve 164. Then, the first supply unit 160 supplies pure water supplied from the pure water supply source 165 to the bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2 via the valve 164. Thus, the 1st supply part 160 supplies pure water as a hydrophilic treatment liquid with respect to the upper wafer W1 or the lower wafer W2.

  Specifically, the surface hydrophilizing device 40 first rotates the upper wafer W1 or the lower wafer W2 at a predetermined rotation speed (for example, 1000 rpm) using the spin chuck 150. Subsequently, the surface hydrophilization device 40 uses the first turning lift mechanism 163 to turn the first arm 162 to place the first nozzle 161 above the center of the upper wafer W1 or the lower wafer W2. And the surface hydrophilization apparatus 40 supplies the pure water which is a hydrophilization process liquid from the 1st nozzle 161 with respect to the rotating upper wafer W1 or lower wafer W2.

  The bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 are modified by the surface modification device 30, and pure water which is a hydrophilic treatment liquid is supplied to the modified bonding surfaces W1j and W2j. As a result, hydroxyl groups (silanol groups) adhere to the bonding surfaces W1j and W2j, and the bonding surfaces W1j and W2j are hydrophilized.

  Here, of the pure water supplied from the first nozzle 161 to the joint surfaces W1j and W2j, a part of the pure water is used to hydrophilize the joint surfaces W1j and W2j as described above. Pure water remains on the joint surfaces W1j and W2j.

  When the upper wafer W1 and the lower wafer W2 are bonded by the bonding apparatus 41 described later in a state where excess pure water remains on the bonding surfaces W1j and W2j in this way, for example, the temperature in the clean room where the bonding system 1 is installed, Depending on the humidity, bubbles (edge voids) may be generated at the peripheral edge between the upper wafer W1 and the lower wafer W2.

  Here, for example, the following reasons can be considered as one of the reasons why the edge void is generated in the peripheral portion. In other words, in the bonding system 1 according to the present embodiment, the bonding portion between the upper wafer W1 and the lower wafer W2 diffuses substantially concentrically from the center of the upper wafer W1 and the lower wafer W2 toward the peripheral edge. Along with the diffusion of the bonding portion, the pure water remaining on the bonding surfaces W1j and W2j is pushed out from the central portion of the upper wafer W1 and the lower wafer W2 to the peripheral portion, and the pure water that has reached the peripheral portion is vaporized. It is considered that edge voids are generated at the peripheral edge between the wafer W1 and the lower wafer W2. Therefore, it is considered that edge voids are more likely to occur as the amount of pure water remaining on the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 increases.

  When an edge void occurs, the portion cannot be used as a product, leading to a decrease in yield. For this reason, when bonding the upper wafer W1 and the lower wafer W2, it is preferable not to generate edge voids as much as possible.

  Therefore, the surface hydrophilizing device 40 according to the present embodiment includes the second supply unit 170 that supplies gas to the joint surfaces W1j and W2j. The second supply unit 170 moves from the upper side of the upper wafer W1 or the lower wafer W2 to the upper side of the upper wafer W1 or the lower wafer W2, and blows gas onto the upper wafer W1 or the lower wafer W2. Thereby, the moisture remaining on the bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2 can be reduced, and the generation of the above-described edge voids can be suppressed.

  The second supply unit 170 includes a second nozzle 171, a second arm 172 that horizontally supports the second nozzle 171, and a second turning lift mechanism 173 that turns and lifts the second arm 172.

  An N 2 supply source 175 is connected to the second nozzle 171 through a valve 174. Then, the second supply unit 170 supplies N2 supplied from the N2 supply source 175 to the bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2 via the valve 174.

  Specifically, the surface hydrophilization device 40 uses the second turning lift mechanism 173 to turn the second arm 172 and move the second nozzle 171 to the peripheral portion of the upper wafer W1 or the lower wafer W2. N2 is sprayed toward the peripheral edge of the upper wafer W1 or the lower wafer W2.

  In this way, the generation of edge voids can be efficiently suppressed by spraying N2 onto the peripheral edge of the upper wafer W1 or the lower wafer W2 where the edge voids are generated.

  Further, the surface hydrophilizing device 40 has a rotational speed (for example, 2000 rpm) faster than the rotational speed of the upper wafer W1 or the lower wafer W2 when pure water is supplied from the first nozzle 161 to the upper wafer W1 or the lower wafer W2. ), N2 is sprayed on the upper wafer W1 or the lower wafer W2 while the upper wafer W1 or the lower wafer W2 is rotated. Thereby, the pure water remaining on the joint surfaces W1j and W2j can be reduced in a shorter time.

  Further, since N2 supplied from the second supply unit 170 is an inert gas, it does not react with the pure water remaining on the joint surfaces W1j and W2j. Note that the gas supplied from the second supply unit 170 may be an inert gas other than N2, or may be a gas other than the inert gas.

<4. Structure of joining device>
Next, the structure of the joining apparatus 41 mentioned above is demonstrated with reference to FIGS. FIG. 7 is a schematic plan view showing the configuration of the bonding apparatus 41, and FIG. 8 is a schematic side view thereof. FIG. 9 is a schematic side view showing the configuration of the position adjusting mechanism. FIG. 10 is a schematic plan view showing the configuration of the reversing mechanism, and FIGS. 11 and 12 are schematic side views thereof. FIG. 13 is a schematic side view showing the configuration of the holding arm and the holding member. 14 is a schematic side view showing configurations of the upper chuck 230 and the lower chuck 231. FIG. 15 is a schematic plan view of the upper chuck as viewed from below. FIG. 16 is a diagram of the lower chuck as viewed from above. It is a schematic plan view.

  As shown in FIG. 7, the joining device 41 includes a processing container 190 that can seal the inside. A loading / unloading port 191 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is formed on the side surface of the processing container 190 on the transfer area 60 side, and an opening / closing shutter 192 is provided at the loading / unloading port 191.

  The inside of the processing container 190 is divided into a transport area T1 and a processing area T2 by an inner wall 193. The loading / unloading port 191 described above is formed on the side surface of the processing container 190 in the transfer region T1. In addition, a carry-in / out port 194 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is also formed on the inner wall 193.

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

  A transport mechanism 201 is provided in the transport region T1. As shown in FIGS. 7 and 8, the transport mechanism 201 has a transport arm that can move around the vertical direction, the horizontal direction, and the vertical axis, for example. Then, the transport mechanism 201 transports the upper wafer W1, the lower wafer W2, and the overlapped wafer T within the transport region T1 or between the transport region T1 and the processing region T2.

  A position adjustment mechanism 210 that adjusts the horizontal orientation of the upper wafer W1 and the lower wafer W2 is provided on the Y axis positive direction side of the transfer region T1. As shown in FIG. 9, the position adjustment mechanism 210 detects the positions of the base 211, the holding unit 212 that sucks and holds the upper wafer W1 and the lower wafer W2, and the notch portions of the upper wafer W1 and the lower wafer W2. And a detecting unit 213 that performs the above-described operation.

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

  In addition, a reversing mechanism 220 that reverses the front and back surfaces of the upper wafer W1 is provided in the transfer region T1. The reversing mechanism 220 has a holding arm 221 that holds the upper wafer W1 as shown in FIGS.

  The holding arm 221 extends in the horizontal direction. The holding arm 221 is provided with holding members 222 for holding the upper wafer W1, for example, at four locations. As shown in FIG. 13, the holding member 222 is configured to be movable in the horizontal direction with respect to the holding arm 221. A cutout 223 for holding the outer peripheral portion of the upper wafer W1 is formed on the side surface of the holding member 222. These holding members 222 can sandwich and hold the upper wafer W1.

  As shown in FIGS. 10 to 13, the holding arm 221 is supported by a first driving unit 224 provided with, for example, a motor. By this first drive unit 224, the holding arm 221 is rotatable around a horizontal axis. The holding arm 221 is rotatable about the first driving unit 224 and is movable in the horizontal direction.

  Below the first drive unit 224, for example, a second drive unit 225 including a motor or the like is provided. By the second drive unit 225, the first drive unit 224 is movable in the vertical direction along the support pillar 226 extending in the vertical direction.

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

  As shown in FIGS. 7 and 8, an upper chuck 230 that holds the upper wafer W1 by suction on the lower surface and a lower chuck 231 that sucks and holds the lower wafer W2 on the upper surface are provided in the processing region T2. The lower chuck 231 is provided below the upper chuck 230 and is configured to be disposed so as to face the upper chuck 230. That is, the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 can be arranged to face each other.

  As shown in FIG. 8, the upper chuck 230 is supported by a support member 232 provided on the ceiling surface of the processing container 190. The support member 232 supports the outer peripheral portion of the upper surface of the upper chuck 230. A chuck driving unit 234 is provided below the lower chuck 231 via a shaft 233. The chuck driving unit 234 moves the lower chuck 231 in the vertical direction and the horizontal direction, and rotates it around the vertical axis.

  In addition, below the lower chuck | zipper 231, the raising / lowering pin (not shown) which supports and raises the lower wafer W2 from the downward direction is provided. The elevating pins are configured to be able to protrude from the upper surface of the lower chuck 231 through a through hole (not shown) formed in the lower chuck 231.

  As shown in FIG. 14, the upper chuck 230 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 center of the upper chuck 230 toward the outer periphery as shown in FIG. The region 230a has a circular shape in plan view, and the regions 230b and 230c have an annular shape in plan view.

  As shown in FIG. 14, suction tubes 240a, 240b, and 240c for sucking and holding the upper wafer W1 are provided in each of the regions 230a, 230b, and 230c, respectively. Different vacuum pumps 241a, 241b, 241c are connected to the suction tubes 240a, 240b, 240c, respectively. Thus, the upper chuck 230 is configured to be able to set the evacuation of the upper wafer W1 for each of the regions 230a, 230b, and 230c.

  In the following, the three regions 230a, 230b, and 230c described above may be referred to as a first region 230a, a second region 230b, and a third region 230c, respectively. In addition, the suction tubes 240a, 240b, and 240c may be referred to as a first suction tube 240a, a second suction tube 240b, and a third suction tube 240c, respectively. Further, the vacuum pumps 241a, 241b, and 241c may be referred to as a first vacuum pump 241a, a second vacuum pump 241b, and a third vacuum pump 241c, respectively.

  Inside the upper chuck 230, a first heating mechanism 242 for heating the upper wafer W1 is provided. For the first heating mechanism 242, for example, a heater is used. Note that the upper chuck 230 is not necessarily provided with the first heating mechanism 242.

  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 of the upper wafer W1 that is sucked and held by the upper chuck 230. And the pushing pin 251 of the pushing member 250 mentioned later is penetrated by the through-hole 243. As shown in FIG.

  On the upper surface of the upper chuck 230, a pushing member 250 that pushes the central portion of the upper wafer W1 is provided. The pushing member 250 has a cylinder structure and includes a pushing pin 251 and an outer cylinder 252 that serves as a guide when the pushing pin 251 moves up and down. The push pin 251 can be moved up and down in the vertical direction through the through hole 243 by, for example, a drive unit (not shown) incorporating a motor. The pushing member 250 can press the central portion of the upper wafer W1 and the central portion of the lower wafer W2 in contact with each other when the upper wafer W1 and the lower wafer W2 described later are joined.

  The upper chuck 230 is provided with an upper imaging member 253 that images the bonding surface W2j of the lower wafer W2. For the upper imaging member 253, for example, a wide-angle CCD camera is used. The upper imaging member 253 may be provided on the upper chuck 230.

  As shown in FIG. 16, the lower chuck 231 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 center of the lower chuck 231 toward the outer periphery. The region 231a has a circular shape in plan view, and the region 231b has an annular shape in plan view.

  As shown in FIG. 14, suction tubes 260a and 260b for sucking and holding the lower wafer W2 are provided in each of the regions 231a and 231b, respectively. Different vacuum pumps 261a and 261b are connected to the suction tubes 260a and 260b, respectively. Thus, the lower chuck 231 is configured to be able to set the evacuation of the lower wafer W2 for each of the regions 231a and 231b.

  Inside the lower chuck 231 is provided a second heating mechanism 262 for heating the lower wafer W2. For the second heating mechanism 262, for example, a heater is used. Note that the lower chuck 231 does not necessarily include the second heating mechanism 262.

  A stopper member 263 that prevents the upper wafer W1, the lower wafer W2, and the overlapped wafer T from jumping out of the lower chuck 231 or sliding down is provided on the outer peripheral portion of the lower chuck 231. The stopper member 263 extends in the vertical direction so that the top of the stopper member 263 is positioned at least above the overlapped wafer T on the lower chuck 231. Further, as shown in FIG. 16, the stopper member 263 is provided at a plurality of places, for example, five places on the outer peripheral portion of the lower chuck 231.

  As shown in FIG. 14, the lower chuck 231 is provided with a lower imaging member 264 that images the bonding surface W1j of the upper wafer W1. For the lower imaging member 264, for example, a wide-angle CCD camera is used. The lower imaging member 264 may be provided on the lower chuck 231.

  As shown in FIG. 1, the bonding system 1 includes a control device 300. The control device 300 controls the operation of the bonding system 1. The control device 300 is a computer, for example, and includes a control unit and a storage unit (not shown). The storage unit stores a program for controlling various processes such as a bonding process. The control unit controls the operation of the bonding system 1 by reading and executing the program stored in the storage unit.

  Such a program may be recorded on a computer-readable recording medium and installed in the storage unit of the control device 300 from the recording medium. Examples of the computer-readable recording medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

<5. Specific operation of joining system>
Next, a specific operation of the joining system 1 configured as described above will be described with reference to FIGS. 17 and 18A to 18F. FIG. 17 is a flowchart showing a processing procedure of processing executed by the joining system 1. 18A to 18F are operation explanatory views of the bonding apparatus 41.

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

  Next, the upper wafer W1 is transferred by the transfer device 61 to the surface modification device 30 of the first processing block G1. The upper wafer W1 carried into the surface modification device 30 is transferred from the transfer device 61 to the upper surface of the lower electrode 80 and placed thereon. Thereafter, the transfer device 61 leaves the surface modification device 30 and the gate valve 72 is closed.

  Thereafter, the vacuum pump 131 is operated, and the atmosphere inside the processing container 70 is reduced to a predetermined degree of vacuum, for example, 67 Pa to 333 Pa (0.5 Torr to 2.5 Torr) through the air inlet 130. As will be described later, the atmosphere in the processing container 70 is maintained at the predetermined degree of vacuum during processing of the upper wafer W1.

  Further, a high voltage set to a DC voltage of, for example, 2500 V is applied from the high voltage power supply 96 to the conductive film 93 of the electrostatic chuck 90. Thus, the upper wafer W 1 is electrostatically attracted to the upper surface of the lower electrode 80 by the Coulomb force generated by the high voltage applied to the electrostatic chuck 90. Further, the upper wafer W1 electrostatically attracted to the lower electrode 80 is maintained at a predetermined temperature, for example, 25 ° C. to 30 ° C. by the heat medium in the heat medium circulation channel 82.

  Thereafter, the processing gas supplied from the gas supply source 122 is uniformly supplied into the processing container 70 from the gas outlet 125 on the lower surface of the upper electrode 110. Then, a high frequency voltage of 2 MHz, for example, is applied from the first high frequency power supply 106 to the lower electrode 80, and a high frequency voltage of, for example, 60 MHz is applied from the second high frequency power supply 112 to the upper electrode 110. As a result, an electric field is formed between the upper electrode 110 and the lower electrode 80, and the processing gas supplied into the processing container 70 is turned into plasma by the electric field.

  By this processing gas plasma (hereinafter sometimes referred to as “processing plasma”), the bonding of SiO 2 is broken so that the bonding surface W 1 j of the upper wafer W 1 on the lower electrode 80 is easily hydrophilized thereafter. In addition, the organic matter on the joint surface W1j is removed. At this time, the oxygen gas plasma in the processing plasma mainly contributes to the removal of organic substances on the bonding surface W1j. Further, the oxygen gas plasma can promote oxidation of the bonding surface W1j of the upper wafer W1, that is, hydrophilicity. Further, the argon gas plasma in the processing plasma has a certain amount of high energy, and the organic matter on the bonding surface W1j is positively (physically) removed by the argon gas plasma. Further, the argon gas plasma has an effect of removing residual moisture contained in the atmosphere in the processing vessel 70. Thus, the bonding surface W1j of the upper wafer W1 is modified by the processing plasma (step S101 in FIG. 17).

  Next, the upper wafer W1 is carried into the surface hydrophilizing device 40 of the second processing block G2 by the transfer device 61. The upper wafer W1 carried into the surface hydrophilizing device 40 is transferred from the transfer device 61 to the spin chuck 150 and is sucked and held.

  Subsequently, the first arm 162 is pivoted so that the first nozzle 161 is positioned above the center of the upper wafer W1. Thereafter, pure water is supplied from the first nozzle 161 onto the upper wafer W1 while rotating the upper wafer W1 by the spin chuck 150. Then, a hydroxyl group (silanol group) adheres to the bonding surface W1j of the upper wafer W1 modified by the surface modification device 30, and the bonding surface W1j is hydrophilized (step S102 in FIG. 17).

  Subsequently, the first nozzle 161 is moved to the outside of the upper wafer W1, the rotational speed of the upper wafer W1 is increased by the spin chuck 150, and then the second arm 172 is turned to move the second nozzle 171 to the upper wafer. It is located above the peripheral edge of W1. And N2 is sprayed from the 2nd nozzle 171 with respect to the peripheral part of the upper wafer W1 (step S103 of FIG. 17). Thereby, the pure water remaining at the peripheral edge of the upper wafer W1 is reduced, and the generation of edge voids is suppressed.

  Next, the upper wafer W1 is carried into the bonding device 41 of the second processing block G2 by the transfer device 61. The upper wafer W <b> 1 carried into the bonding apparatus 41 is transferred to the position adjustment mechanism 210 by the transfer mechanism 201 through the transition 200. Then, the horizontal adjustment of the upper wafer W1 is adjusted by the position adjustment mechanism 210 (step S104 in FIG. 17).

  Thereafter, the upper wafer W <b> 1 is delivered from the position adjustment mechanism 210 to the holding arm 221 of the reversing mechanism 220. Subsequently, by reversing the holding arm 221 in the transfer region T1, the front and back surfaces of the upper wafer W1 are reversed (step S105 in FIG. 17). Thereby, the bonding surface W1j of the upper wafer W1 is directed downward.

  Thereafter, the holding arm 221 of the reversing mechanism 220 rotates around the first driving unit 224 and moves below the upper chuck 230. Then, the upper wafer W 1 is delivered from the reversing mechanism 220 to the upper chuck 230. The non-bonding surface W1n of the upper wafer W1 is sucked and held by the upper chuck 230 (Step S106 in FIG. 17).

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

  While the processes of steps S101 to S106 described above are performed on the upper wafer W1, the process of the lower wafer W2 is performed following the upper wafer W1. First, the lower wafer W2 in the cassette C2 is taken out by the transfer device 22 and transferred to the transition device 50 of the processing station 3.

  Next, the lower wafer W2 is transferred to the surface modification device 30 by the transfer device 61, and the bonding surface W2j of the lower wafer W2 is modified in the same procedure as the upper wafer W1 described above (step S107 in FIG. 17). ).

  Next, the lower wafer W <b> 2 is carried into the surface hydrophilizing device 40 by the transfer device 61. The lower wafer W2 carried into the surface hydrophilization device 40 is transferred from the transfer device 61 to the spin chuck 150 and is sucked and held.

  Subsequently, the first arm 162 is pivoted so that the first nozzle 161 is positioned above the center of the lower wafer W2. Thereafter, pure water is supplied from the first nozzle 161 onto the lower wafer W2 while rotating the lower wafer W2 by the spin chuck 150. Then, a hydroxyl group (silanol group) adheres to the bonding surface W2j of the lower wafer W2 modified by the surface modification device 30, and the bonding surface W2j is hydrophilized (step S108 in FIG. 17).

  Subsequently, the first nozzle 161 is moved to the outside of the lower wafer W2, the rotational speed of the lower wafer W2 is increased by the spin chuck 150, and then the second arm 172 is turned to move the second nozzle 171 to the lower wafer. It is located above the peripheral edge of W2. And N2 is sprayed from the 2nd nozzle 171 with respect to the peripheral part of the lower wafer W2 (step S109 of FIG. 17). Thereby, the pure water remaining at the peripheral edge of the lower wafer W2 is reduced, and the generation of edge voids is suppressed.

  Note that the surface hydrophilizing apparatus 40 may vary the flow rate or time of N2 supplied to the upper wafer W1 and the lower wafer W2 between the upper wafer W1 and the lower wafer W2. For example, the surface hydrophilizing apparatus 40 makes the flow rate or time of N2 supplied to the upper wafer W1 that is a product wafer larger or longer than the flow rate or time of N2 supplied to the lower wafer W2 that is a bare wafer. May be.

  An electronic circuit is formed on the bonding surface W1j of the upper wafer W1, which is a product wafer. Alternatively, a film such as an HDP oxide film is formed on the bonding surface W1j on which the electronic circuit is formed. On the other hand, the bonding surface W2j of the lower wafer W2 that is a bare wafer is a flat surface. For this reason, there is a possibility that pure water is likely to remain on the bonding surface W1j of the upper wafer W1 as compared to the bonding surface W2j of the lower wafer W2. In other words, the bonding surface W2j of the lower wafer W2 is easier to remove the remaining pure water than the bonding surface W1j of the upper wafer W1.

  Therefore, the time required for a series of bonding processes can be shortened by making the flow rate or time of N2 supplied to the upper wafer W1 larger or longer than the flow rate or time of N2 supplied to the lower wafer W2. Can do.

  Thereafter, the lower wafer W <b> 2 is carried into the bonding apparatus 41 by the transfer device 61. The lower wafer W <b> 2 carried into the bonding apparatus 41 is transferred to the position adjustment mechanism 210 by the transfer mechanism 201 through the transition 200. Then, the horizontal adjustment of the lower wafer W2 is adjusted by the position adjustment mechanism 210 (step S110 in FIG. 17).

  Thereafter, the lower wafer W2 is transferred to the lower chuck 231 by the transfer mechanism 201, and is sucked and held by the lower chuck 231 (step S111 in FIG. 17). At this time, all the vacuum pumps 261a and 261b are operated, and the lower wafer W2 is evacuated in all the regions 231a and 231b of the lower chuck 231. Then, the non-bonding surface W2n of the lower wafer W2 is attracted and held by the lower chuck 231 so that the bonding surface W2j of the lower wafer W2 faces upward.

  Next, the horizontal position adjustment of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 is performed. As shown in FIG. 18A, a plurality of predetermined points, for example, four or more reference points A are formed on the bonding surface W2j of the lower wafer W2, and similarly, a plurality of predetermined points are formed on the bonding surface W1j of the upper wafer W1. For example, four or more reference points B are formed. As these reference points A and B, for example, predetermined patterns formed on the upper wafer W1 or the lower wafer W2 are used. Then, the upper imaging member 253 is moved in the horizontal direction, and the bonding surface W2j of the lower wafer W2 is imaged. Further, the lower imaging member 264 is moved in the horizontal direction, and the bonding surface W1j of the upper wafer W1 is imaged.

  Thereafter, the position of the reference point A of the lower wafer W2 displayed in the image captured by the upper imaging member 253 matches the position of the reference point B of the upper wafer W1 displayed in the image captured by the lower imaging member 264. Thus, the horizontal position (including the horizontal direction) of the lower wafer W2 is adjusted by the lower chuck 231. That is, the chuck drive unit 234 moves the lower chuck 231 in the horizontal direction, and adjusts the horizontal position of the lower wafer W2. Thus, the horizontal position of the upper wafer W1 and the lower wafer W2 is adjusted (step S112 in FIG. 17). Note that the lower chuck 231 may be moved instead of moving the upper imaging member 253 and the lower imaging member 264.

  The horizontal orientations of the upper wafer W1 and the lower wafer W2 are adjusted by the position adjusting mechanism 210 in step S104 and step S110, but fine adjustment is performed in step S112. In step S112 of the present embodiment, a predetermined pattern formed on the upper wafer W1 or the lower wafer W2 is used as the reference points A and B. However, other reference points may be used. For example, the outer peripheral portion and the notch portion of the upper wafer W1 or the lower wafer W2 can be used as the reference points.

  Thereafter, as shown in FIG. 18B, the lower chuck 231 is raised by the chuck driving unit 234, and the lower wafer W2 is placed at a predetermined position. At this time, the lower wafer W2 is arranged such that the distance between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 is a predetermined distance, for example, 80 μm to 200 μm. Thus, the vertical positions of the upper wafer W1 and the lower wafer W2 are adjusted (step S113 in FIG. 17).

  In steps S106 to S113, the upper wafer W1 is evacuated in all the regions 230a, 230b, and 230c of the upper chuck 230. Similarly, in steps S111 to S113, the lower wafer W2 is evacuated in all the regions 231a and 231b of the lower chuck 231.

  Thereafter, the operation of the first vacuum pump 241a is stopped, and the evacuation of the upper wafer W1 from the first suction tube 240a in the first region 230a is stopped as shown in FIG. 18C. At this time, in the second region 230b and the third region 230c, the upper wafer W1 is vacuumed and held by suction. Thereafter, by lowering the push pin 251 of the push member 250, the upper wafer W1 is lowered while pressing the central portion of the upper wafer W1. At this time, a load such as 200 g is applied to the push pin 251 so that the push pin 251 moves by 70 μm in the absence of the upper wafer W1. Then, the central portion of the upper wafer W1 and the central portion of the lower wafer W2 are brought into contact with each other and pressed by the pushing member 250 (step S114 in FIG. 17).

  Then, bonding starts between the pressed center portion of the upper wafer W1 and the center portion of the lower wafer W2 (thick line portion in FIG. 18C). That is, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified in steps S101 and S107, first, van der Waals force (intermolecular force) is generated between the bonding surfaces W1j and W2j. As a result, the joint surfaces W1j and W2j are joined together. Further, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are hydrophilized in steps S102 and S108, respectively, the hydrophilic groups between the bonding surfaces W1j and W2j are hydrogen-bonded, and the bonding surfaces W1j and W2j. They are firmly joined together.

  Thereafter, as shown in FIG. 18D, in a state where the central portion of the upper wafer W1 and the central portion of the lower wafer W2 are pressed by the pushing member 250, the operation of the second vacuum pump 241b is stopped, and the second region 230b The evacuation of the upper wafer W1 from the second suction tube 240b is stopped.

  As a result, the upper wafer W1 held in the second region 230b falls onto the lower wafer W2. Thereafter, the operation of the third vacuum pump 241c is stopped, and the evacuation of the upper wafer W1 from the third suction tube 240c in the third region 230c is stopped. In this way, evacuation of the upper wafer W1 is stopped from the center portion of the upper wafer W1 toward the outer peripheral portion, and the upper wafer W1 sequentially falls and contacts the lower wafer W2. And the joining by the van der Waals force and hydrogen bond between the joint surfaces W1j and W2j described above is sequentially expanded.

  Thus, as shown in FIG. 18E, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into contact with each other, and the upper wafer W1 and the lower wafer W2 are bonded (Step S115 in FIG. 17).

  In step S115, bonding in which the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 are diffused, that is, a so-called bonding wave is generated. In the bonding system 1 according to the present embodiment, since excess pure water is removed from the upper wafer W1 and the lower wafer W2 in steps S103 and S109, the generation of edge voids is suppressed. Therefore, according to the bonding system 1 according to the present embodiment, the upper wafer W1 and the lower wafer W2 can be bonded appropriately.

  Thereafter, as shown in FIG. 18F, the pushing member 250 is raised to the upper chuck 230. Further, the lower chuck 231 stops evacuation of the lower wafer W2 from the suction pipes 260a and 260b, and the lower chuck 231 stops holding the lower wafer W2 by suction.

  The superposed wafer T joined with the upper wafer W1 and the lower wafer W2 is transferred to the transition device 51 by the transfer device 61, and then transferred to the cassette C3 of the predetermined mounting plate 11 by the transfer device 22 of the loading / unloading station 2. The In this way, a series of joining processing of the upper wafer W1 and the lower wafer W2 is completed.

  As described above, the bonding system 1 according to this embodiment includes the surface modification device 30, the surface hydrophilization device 40, and the bonding device 41. The surface modification device 30 modifies the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2. The surface hydrophilizing device 40 hydrophilizes the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 modified by the surface modifying device 30. The bonding apparatus 41 bonds the upper wafer W1 and the lower wafer W2 that have been hydrophilized by the surface hydrophilizing apparatus 40. The surface hydrophilizing device 40 includes a holding unit 151, a first nozzle 161 (corresponding to an example of a liquid supply unit), and a second nozzle 171 (corresponding to an example of a gas supply unit). The holding unit 151 holds the upper wafer W1 or the lower wafer W2. The first supply unit 160 supplies pure water, which is a hydrophilic treatment liquid, to the modified bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2 held by the holding unit 151. The second supply unit 170 supplies N2 to the bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2 to which pure water is supplied by the first supply unit 160.

  Therefore, according to the joining system 1 which concerns on this embodiment, it can suppress that a bubble generate | occur | produces in the peripheral part between board | substrates, and can board | substrates appropriately.

  By the way, in embodiment mentioned above, it was decided to reduce the water | moisture content which remain | survives in the peripheral part of bonding surface W1j, W2j by supplying N2 to the peripheral part of bonding surface W1j, W2j of upper wafer W1 or lower wafer W2. However, N2 may be supplied to places other than the peripheral portions of the joint surfaces W1j and W2j.

  For example, the surface hydrophilizing device 40 may supply N2 to the joint surfaces W1j and W2j while scanning the second nozzle 171 from the central part to the peripheral part of the joint surfaces W1j and W2j. Thereby, the water | moisture content remaining in places other than the peripheral part of joining surface W1j and W2j can also be reduced.

  As described above, even when the second nozzle 171 is scanned, it is preferable to supply N2 mainly to the peripheral portions of the joint surfaces W1j and W2j. For example, the surface hydrophilizing device 40 may gradually decrease the scanning speed of the second nozzle 171 as it goes from the central part to the peripheral part of the joint surfaces W1j and W2j. Further, the surface hydrophilizing device 40 scans the second nozzle 171 from the central part of the joint surfaces W1j and W2j toward the peripheral part at a constant speed, and then stops the second nozzle 171 at the peripheral part of the joint surfaces W1j and W2j. N2 may be supplied for a predetermined time in the field.

  In this way, edge voids generated at the peripheral portions of the joint surfaces W1j and W2j can be more efficiently suppressed by supplying N2 to the peripheral portions of the joint surfaces W1j and W2j.

<Other embodiments>
The structure of the surface hydrophilization apparatus which this application discloses is not limited to the structure mentioned above. Below, the other structural example of a surface hydrophilization apparatus is demonstrated with reference to FIG. 19A and FIG. 19B. FIG. 19A is a schematic side view showing the configuration of the surface hydrophilizing apparatus according to the first modification, and FIG. 19B is a schematic side view showing the configuration of the surface hydrophilizing apparatus according to the second modification.

  In the following description, parts that are the same as those already described are given the same reference numerals as those already described, and redundant descriptions are omitted.

  The surface hydrophilizing apparatus 40A according to the first modification shown in FIG. 19A includes a supply unit 160A. 160 A of supply parts are provided with the 1st nozzle 161, the 2nd nozzle 171, the arm 162A which supports the 1st nozzle 161 and the 2nd nozzle 171, and the turning raising / lowering mechanism 163A which turns and raises / lowers the arm 162A. The first nozzle 161 is connected to the pure water supply source 165 via the valve 164, and the second nozzle 171 is connected to the N 2 supply source 175 via the valve 174.

  Thus, the 1st nozzle 161 which supplies a pure water, and the 2nd nozzle 171 which supplies N2 may be provided in one arm.

  Moreover, the surface hydrophilization apparatus 40B which concerns on the 2nd modification shown to FIG. 19B is provided with the supply part 160B. The supply unit 160B includes a third nozzle 400, an arm 162B that supports the third nozzle 400, and a swivel lifting mechanism 163B that swivels and lifts the arm 162B.

  The third nozzle 400 is, for example, a two-fluid nozzle. The two-fluid nozzle generates droplets by mixing gas and liquid, and ejects the generated droplets. The third nozzle 400 is connected to the pure water supply source 165 via the valve 164 and is connected to the N2 supply source 175 via the valve 174. Note that any conventional technique may be used for the configuration of the third nozzle 400.

  In the surface hydrophilizing device 40B, for example, droplets generated by mixing pure water and N2 from the third nozzle 400 are sprayed onto the upper wafer W1 or the lower wafer W2, thereby causing the upper wafer W1 or the lower wafer W2 to be ejected. The particles adhering to the joint surfaces W1j and W2j are removed.

  Thereafter, the valve 174 is closed, and only the pure water is supplied from the third nozzle 400 to the joint surfaces W1j and W2j, thereby hydrophilizing the joint surfaces W1j and W2j. Then, the valve 164 is closed, the valve 174 is opened, and only N2 is supplied from the third nozzle 400 to the joint surfaces W1j and W2j, thereby reducing the moisture remaining on the joint surfaces W1j and W2j.

  Further, the third nozzle 400 may be a normal nozzle instead of a two-fluid nozzle. In such a case, first, only the valve 164 is opened to make the joint surfaces W1j and W2j hydrophilic, and then only the valve 174 is opened to reduce the pure water remaining on the joint surfaces W1j and W2j. Thus, pure water and N2 may be supplied using a single nozzle.

  Note that the surface hydrophilizing apparatus 40A according to the first modification may include a third nozzle 400 instead of the first nozzle 161. In such a case, particles may be removed and hydrophilized using the third nozzle 400, and pure water remaining on the joint surfaces W1j and W2j may be removed using the second nozzle 171. Unlike the third nozzle 400, pure water does not remain in the second nozzle 171, so that the pure water remaining on the joint surfaces W1j and W2j can be reduced in a shorter time.

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

W1 Upper wafer W2 Lower wafer T Superposition wafer 1 Bonding system 2 Loading / unloading station 3 Processing station 30 Surface modification device 40 Surface hydrophilization device 41 Bonding device 230 Upper chuck 231 Lower chuck 300 Controller

Claims (6)

A bonding method for bonding substrates by intermolecular force,
A surface modification step for modifying the surface to which the substrate is bonded;
A surface hydrophilization step of hydrophilizing the surface by supplying a hydrophilization treatment liquid to the surface of the substrate modified by the surface modification step;
A gas supply step of supplying a gas to the surface of the substrate hydrophilized by the surface hydrophilization step to reduce the hydrophilization treatment liquid remaining on the surface;
A bonding step of bonding the substrates after the gas supply step. The gas supply step includes
A gas supply unit that supplies gas to the surface of the substrate is positioned at a peripheral portion of the surface of the substrate, and then gas is supplied from the gas supply unit toward the peripheral portion. Item 2. The joining method according to Item 1. The gas supply step includes
Gas is supplied from the gas supply unit toward the surface of the substrate while moving a gas supply unit that supplies gas to the surface of the substrate from a central part to a peripheral part of the surface of the substrate. The joining method according to claim 1. The gas supply step includes
The bonding method according to claim 3, wherein the moving speed of the gas supply unit is gradually decreased as the gas supply unit moves from the central portion to the peripheral portion of the surface of the substrate. The gas supply step includes
The gas supply unit is moved from the central part of the surface of the substrate to the peripheral part while supplying gas from the gas supply part to the surface of the substrate, and then the gas supply part is stopped at the peripheral part of the substrate. The bonding method according to claim 3, wherein gas is supplied from the gas supply unit toward the peripheral portion. A bonding system that bonds substrates by intermolecular force,
A surface modification device for modifying a surface to which the substrate is bonded;
A surface hydrophilizing device for hydrophilizing the surface of the substrate modified by the surface modifying device;
A bonding device for bonding the substrates hydrophilized by the surface hydrophilizing device,
The surface hydrophilizing device is:
A holding unit for holding the substrate;
A liquid supply unit that supplies a hydrophilic treatment liquid to the modified surface of the substrate held by the holding unit;
A gas supply unit that supplies a gas to the surface of the substrate to which the hydrophilization liquid is supplied by the liquid supply unit.

Images