Bonding device, bonding system, and bonding method

Abstract

An engagement device (41) according to one embodiment of the present disclosure has a first holding part (140), a second holding part (141), and a striker pin (190). The first holding unit (140) sucks and holds the first substrate (W1) from above the first substrate (W1). The second holding section (141) is disposed below the first holding section (140), and sucks and holds the second substrate (W2) from below the second substrate (W2). The striker pin (190) presses the central part of the first substrate (W1) to make the central part of the first substrate (W1) contact with the second substrate (W2). The first holding section (140) has a main body section (170) and a negative pressure forming section (320). The main body section (170) has a lower surface (170a) facing the first substrate (W1). The negative pressure forming part (320) is used for forming negative pressure in a space between the lower surface (170a) of the main body part (170) and the upper surface (W1n) of the first substrate (W1), wherein the lower surface (170a) and the upper surface (W1n) are separated by pressing the striker pin (190).

Description

Technical Field

[0001] The present disclosure relates to a bonding device, a bonding system, and a bonding method. Background Art

[0002] Conventionally, a bonding device for bonding substrates such as semiconductor wafers has been known (see Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-147944 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The present disclosure provides a technique capable of improving the bonding accuracy between substrates.

[0008] Solutions to the Problems

[0009] A bonding device according to one aspect of the present disclosure includes a first holding unit, a second holding unit, and a plunger. The first holding unit sucks and holds the first substrate from above the first substrate. The second holding unit is disposed at a position lower than the first holding unit and sucks and holds the second substrate from below the second substrate. The plunger presses the central portion of the first substrate to bring the central portion of the first substrate into contact with the second substrate. In addition, the first holding unit includes a main body portion and a negative pressure forming portion. The main body portion has a lower surface facing the first substrate. The negative pressure forming portion forms a negative pressure in a space between the lower surface of the main body portion separated by pressing the plunger and the upper surface of the first substrate.

[0010] Effects of the Invention

[0011] According to the present disclosure, the bonding accuracy between substrates can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram showing the structure of a bonding system according to an embodiment.

[0013] Figure 2 It is a schematic diagram showing the structure of a bonding system according to an embodiment.

[0014] Figure 3 It is a schematic diagram showing a state before bonding a first substrate and a second substrate according to an embodiment.

[0015] Figure 4 It is a schematic diagram showing the structure of a bonding device according to an embodiment.

[0016] Figure 5 It is a schematic diagram showing the structure of the bonding device according to the embodiment.

[0017] Figure 6 It is a schematic diagram showing the first holding part and the second holding part according to the embodiment.

[0018] Figure 7 It is a schematic diagram showing an example of the situation where the bonding area is enlarged.

[0019] Figure 8 It is a schematic diagram showing an example of the situation where the bonding area is enlarged.

[0020] Figure 9 It is a schematic diagram obtained by observing the first holding part from below the first holding part.

[0021] Figure 10 It is a schematic perspective view showing the lower surface side of the main body part in an enlarged manner.

[0022] Figure 11 It is a schematic diagram obtained by observing the first holding part from below the first holding part.

[0023] Figure 12 It is a flowchart showing a part of the processing executed by the bonding system according to the embodiment.

[0024] Figure 13 It is an operation explanatory diagram of the bonding process.

[0025] Figure 14 It is an operation explanatory diagram of the bonding process.

[0026] Figure 15 It is a schematic diagram showing an example of the situation where the bonding area in the bonding device according to the embodiment is enlarged. Detailed Embodiment

[0027] Next, a mode (hereinafter referred to as "embodiment") for implementing the bonding device, the bonding system, and the bonding method of the present disclosure will be described in detail with reference to the drawings. In addition, the bonding device, the bonding system, and the bonding method of the present disclosure are not limited by this embodiment.

[0028] In addition, in each of the drawings referred to below, in order to make the description easy to understand, an orthogonal coordinate system in which 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 set as the vertically upward direction is sometimes shown. In addition, the rotation direction around the vertical axis is sometimes referred to as the θ direction.

[0029] <Bonding System>

[0030] First, refer to Figures 1 to 3To describe the structure of the bonding system involved in the embodiments. Figure 1 and Figure 2 are schematic views showing the structure of the bonding system involved in the embodiments. Additionally, Figure 3 is a schematic view showing the state before bonding of the first substrate and the second substrate involved in the embodiments.

[0031] Figure 1 The bonding system 1 shown forms a stacked substrate T by bonding the first substrate W1 and the second substrate W2 (refer to Figure 3 ).

[0032] The first substrate W1 is a substrate on which a plurality of electronic circuits are formed, for example, on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. Additionally, the second substrate W2 is, for example, a bare wafer on which no electronic circuits are formed. The first substrate W1 and the second substrate W2 have substantially the same diameter. Furthermore, similar to the first substrate W1, the second substrate W2 can also be a substrate on which a plurality of electronic circuits are formed on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer.

[0033] Next, as Figure 3 shown, the surface of the first substrate W1 on the side to be bonded to the second substrate W2 in the plane of the first substrate W1 is denoted as "bonding surface W1j", and the surface on the side opposite to the bonding surface W1j is denoted as "non - bonding surface W1n". Additionally, the surface of the second substrate W2 on the side to be bonded to the first substrate W1 in the plane of the second substrate W2 is denoted as "bonding surface W2j", and the surface on the side opposite to the bonding surface W2j is denoted as "non - bonding surface W2n".

[0034] As Figure 1 shown, the bonding system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 is disposed on the negative X - axis side of the processing station 3 and is integrally connected to the processing station 3.

[0035] The loading / unloading station 2 includes a stage 10 and a transfer area 20. The stage 10 includes a plurality of mounting plates 11. On each mounting plate 11, there are mounted cassettes C1, C2, C3 for accommodating a plurality of (for example, 25) substrates in a horizontal state. For example, cassette C1 is a cassette for accommodating the first substrate W1, cassette C2 is a cassette for accommodating the second substrate W2, and cassette C3 is a cassette for accommodating the stacked substrate T.

[0036] The transfer area 20 is disposed adjacent to the positive X-axis side of the mounting table 10. A transfer path 21 extending in the Y-axis direction and a transfer device 22 capable of moving along the transfer path 21 are provided in the transfer area 20. The transfer device 22 can not only move in the Y-axis direction but also move in the X-axis direction and can rotate about the Z-axis. The transfer device 22 transfers the first substrate W1, the second substrate W2, and the stacked substrate T between the cassettes C1 to C3 placed on the mounting plate 11 and the third processing block G3 of the processing station 3 described later.

[0037] In addition, the number of the cassettes C1 to C3 placed on the mounting plate 11 is not limited to the number shown in the figure. Further, on the mounting plate 11, in addition to the cassettes C1, C2, and C3, a cassette for recovering substrates in which an abnormal condition has occurred may be placed.

[0038] Three processing blocks G1, G2, and G3 are provided in the processing station 3, for example. The first processing block G1 is disposed on the front side of the processing station 3 ( Figure 1 the negative Y-axis side). Further, the second processing block G2 is disposed on the back side of the processing station 3 ( Figure 1 the positive Y-axis side), and the third processing block G3 is disposed closer to the loading / unloading station 2 side of the processing station 3 ( Figure 1 the negative X-axis side).

[0039] A surface modification device 30 for modifying the bonding surfaces W1j, W2j of the first substrate W1 and the second substrate W2 is disposed in the first processing block G1. The surface modification device 30 cuts the bonds of SiO2 in the bonding surfaces W1j, W2j of the first substrate W1 and the second substrate W2 to form single-bonded SiO, thereby modifying the bonding surfaces W1j, W2j so that the bonding surfaces W1j, W2j can be easily hydrophilized later.

[0040] Specifically, in the surface modification device 30, for example, oxygen or nitrogen as a processing gas is excited in a reduced-pressure atmosphere to be ionized to form plasma. Then, the bonding surfaces W1j, W2j of the first substrate W1 and the second substrate W2 are irradiated with the oxygen ions or nitrogen ions to perform plasma treatment on the bonding surfaces W1j, W2j to modify them.

[0041] In the second processing block G2, a surface hydrophilization device 40 and a bonding device 41 are arranged. The surface hydrophilization device 40 hydrophilizes the bonding surfaces W1j and W2j of the first substrate W1 and the second substrate W2 with pure water, for example, and cleans the bonding surfaces W1j and W2j. Specifically, the surface hydrophilization device 40 supplies pure water to the first substrate W1 or the second substrate W2 while rotating the first substrate W1 or the second substrate W2 held by a rotary holding chuck. Thereby, the pure water supplied to the first substrate W1 or the second substrate W2 diffuses on the bonding surfaces W1j and W2j of the first substrate W1 or the second substrate W2, hydrophilizing the bonding surfaces W1j and W2j.

[0042] The bonding device 41 bonds the hydrophilized first substrate W1 and the second substrate W2 by intermolecular forces. The structure of the bonding device 41 will be described later.

[0043] As Figure 2 shown, in the third processing block G3, a transfer (TRS) device 50, 51 for the first substrate W1, the second substrate W2, and the superposed substrate T is provided in order from below.

[0044] A transfer area 60 is formed in the area surrounded by the first processing block G1, the second processing block G2, and the third processing block G3. A transfer device 61 is arranged in the transfer area 60. The transfer device 61 has a transfer arm that can move freely in the vertical direction, the horizontal direction, and rotate freely about the vertical axis, for example. The transfer device 61 moves within the transfer area 60 and transfers the first substrate W1, the second substrate W2, and the superposed substrate T to a specified device in the first processing block G1, the second processing block G2, and the third processing block G3 adjacent to the transfer area 60.

[0045] In addition, the bonding system 1 includes a control device 70. The control device 70 controls the operation of the bonding system 1. The control device 70 is a computer, for example, and includes a control unit and a storage unit (not shown). The control unit includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), input / output ports, and various circuits. The CPU of the microcomputer realizes the control described later by reading and executing the program stored in the ROM. In addition, the storage unit is realized by a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk, for example.

[0046] In addition, the program can also be recorded on a computer-readable recording medium and installed from the recording medium into the storage unit of the control device 70. Examples of the computer-readable recording medium include a hard disk (HD), a floppy disk (FD), a compact disc (CD), a magneto-optical disc (MO), a memory card, etc.

[0047] <Bonding device>

[0048] Next, with reference to Figure 4 and Figure 5 the structure of the bonding device 41 will be described. Figure 4 and Figure 5 are schematic views showing the structure of the bonding device 41 according to the embodiment.

[0049] As Figure 4 shown, the bonding device 41 has a processing container 100 that can be sealed inside. An inlet / outlet 101 for the first substrate W1, the second substrate W2, and the stacked substrate T is formed on the side surface of the processing container 100 on the conveyance area 60 side, and an opening / closing shutter 102 is provided at the inlet / outlet 101.

[0050] The inside of the processing container 100 is divided into a conveyance area T1 and a processing area T2 by an inner wall 103. The above-mentioned inlet / outlet 101 is formed on the side surface of the processing container 100 in the conveyance area T1. In addition, an inlet / outlet 104 for the first substrate W1, the second substrate W2, and the stacked substrate T is also formed on the inner wall 103.

[0051] In the conveyance area T1, a transfer unit 110, a substrate transfer mechanism 111, a flipping mechanism 130, and a position adjustment mechanism 120 are arranged in the described order, for example, starting from the inlet / outlet 101 side.

[0052] The transfer unit 110 temporarily holds the first substrate W1, the second substrate W2, and the stacked substrate T. The transfer unit 110 is formed in two layers, for example, and can hold any two of the first substrate W1, the second substrate W2, and the stacked substrate T at the same time.

[0053] As Figure 4 and Figure 5 shown, the substrate transfer mechanism 111 has a transfer arm that can move freely in the vertical direction (Z-axis direction), the horizontal direction (Y-axis direction, X-axis direction), and the direction around the vertical axis (θ direction), for example. The substrate transfer mechanism 111 can transfer the first substrate W1, the second substrate W2, and the stacked substrate T within the conveyance area T1 or between the conveyance area T1 and the processing area T2.

[0054] The position adjusting mechanism 120 adjusts the orientations of the first substrate W1 and the second substrate W2 in the horizontal direction. Specifically, the position adjusting mechanism 120 includes: a base 121 having a holding portion (not shown) that holds and rotates the first substrate W1 and the second substrate W2; and a detection portion 122 that detects the positions of the cut portions of the first substrate W1 and the second substrate W2. The position adjusting mechanism 120 rotates the first substrate W1 and the second substrate W2 held on the base 121 while using the detection portion 122 to detect the positions of the cut portions of the first substrate W1 and the second substrate W2, thereby adjusting the positions of the cut portions. Thereby, the orientations of the first substrate W1 and the second substrate W2 in the horizontal direction are adjusted.

[0055] The flipping mechanism 130 flips the front and back surfaces of the first substrate W1. Specifically, the flipping mechanism 130 has a holding arm 131 that holds the first substrate W1. The holding arm 131 extends in the horizontal direction (X-axis direction). In addition, holding members 132 for holding the first substrate W1 are provided at four positions, for example, on the holding arm 131.

[0056] The holding arm 131 is supported by a driving portion 133 including, for example, a motor. The holding arm 131 is rotatable about a horizontal axis by the driving portion 133. In addition, the holding arm 131 is rotatable about the driving portion 133 and is movable in the horizontal direction (X-axis direction). Another driving portion (not shown) including, for example, a motor is provided below the driving portion 133. By this other driving portion, the driving portion 133 can move in the vertical direction along a support column 134 extending in the vertical direction.

[0057] In this way, the first substrate W1 held by the holding member 132 can rotate about a horizontal axis and can move in the vertical and horizontal directions by the driving portion 133. In addition, the first substrate W1 held by the holding member 132 can rotate about the driving portion 133 to move between the position adjusting mechanism 120 and a first holding portion 140 described later.

[0058] In the processing area T2, a first holding portion 140 that adsorbs and holds the upper surface (non-bonding surface W1n) of the first substrate W1 from above and a second holding portion 141 that adsorbs and holds the lower surface (non-bonding surface W2n) of the second substrate W2 from below are provided. The second holding portion 141 is provided at a position lower than the first holding portion 140 and is configured to be able to be arranged facing the first holding portion 140. The first holding portion 140 and the second holding portion 141 are, for example, vacuum holding disks.

[0059] As Figure 5As shown, the first holding part 140 is supported by a support member 180 provided above the first holding part 140. The support member 180 is fixed to the top surface of the processing container 100 by, for example, a plurality of support columns 181.

[0060] An upper imaging part 145 for imaging the upper surface (bonding surface W2j) of the second substrate W2 held by the second holding part 141 is provided on the side of the first holding part 140. The upper imaging part 145 uses, for example, a CCD camera.

[0061] The second holding part 141 is supported by a first moving part 160 provided below the second holding part 141. The first moving part 160 moves the second holding part 141 in the horizontal direction (X-axis direction) as described later. In addition, the first moving part 160 is configured to move the second holding part 141 freely in the vertical direction and be able to rotate about the vertical axis.

[0062] A lower imaging part 146 for imaging the lower surface (bonding surface W1j) of the first substrate W1 held by the first holding part 140 is provided on the first moving part 160. The lower imaging part 146 uses, for example, a CCD camera.

[0063] The first moving part 160 is mounted on a pair of guide rails 162, 162. The pair of guide rails 162, 162 are provided on the lower surface side of the first moving part 160 and extend in the horizontal direction (X-axis direction). The first moving part 160 is configured to move freely along the guide rails 162.

[0064] The pair of guide rails 162, 162 are disposed on a second moving part 163. The second moving part 163 is mounted on a pair of guide rails 164, 164. The pair of guide rails 164, 164 are provided on the lower surface side of the second moving part 163 and extend in the horizontal direction (Y-axis direction). The second moving part 163 is configured to move freely in the horizontal direction (Y-axis direction) along the guide rails 164. In addition, the pair of guide rails 164, 164 are disposed on a mounting table 165 provided on the bottom surface of the processing container 100.

[0065] A position alignment part 166 is constituted by the first moving part 160, the second moving part 163, etc. The position alignment part 166 performs horizontal position alignment between the first substrate W1 held by the first holding part 140 and the second substrate W2 held by the second holding part 141 by moving the second holding part 141 in the X-axis direction, Y-axis direction, and θ direction. In addition, the position alignment part 166 performs vertical position alignment between the first substrate W1 held by the first holding part 140 and the second substrate W2 held by the second holding part 141 by moving the second holding part 141 in the Z-axis direction.

[0066] In addition, it is set here that the second holding part 141 moves in the X-axis direction, Y-axis direction, and θ direction. However, for example, the position alignment part 166 may also move the second holding part 141 in the X-axis direction and Y-axis direction, and move the first holding part 140 in the θ direction. Further, it is set here that the second holding part 141 moves in the Z-axis direction. However, for example, the position alignment part 166 may also move the first holding part 140 in the Z-axis direction.

[0067] Next, the structures of the first holding part 140 and the second holding part 141 will be described with reference to Figure 6 FIG. Figure 6 FIG. is a schematic view showing the first holding part 140 and the second holding part 141 according to the embodiment.

[0068] As Figure 6 shown, the first holding part 140 has a main body part 170. The main body part 170 is supported by a support member 180. The main body part 170 is configured to have the same diameter as or a larger diameter than the diameter of the first substrate W1. Further, the main body part 170 has a lower surface 170a facing the first substrate W1. Specifically, the main body part 170 has a lower surface 170a facing the upper surface (non-bonding surface W1n) of the first substrate W1 to be adsorbed and held. In addition, hereinafter, the non-bonding surface W1n of the first substrate W1 may sometimes be referred to as the "upper surface W1n" of the first substrate W1.

[0069] A through hole 176 penetrating the support member 180 and the main body part 170 in the vertical direction is formed in the support member 180 and the main body part 170. The position of the through hole 176 corresponds to the central portion of the first substrate W1 adsorbed and held by the first holding part 140. The pressing pin 191 of the knock pin 190 is inserted into the through hole 176.

[0070] The knock pin 190 is disposed on the upper surface of the support member 180. The knock pin 190 includes a pressing pin 191, an actuator part 192, and a linear motion mechanism 193. The pressing pin 191 is a columnar member extending in the vertical direction and is supported by the actuator part 192.

[0071] The actuator part 192 generates a certain pressure in the fixed direction (here, vertically downward) by, for example, air supplied from an electro-pneumatic regulator (not shown). The actuator part 192 can control the pressing load applied to the central portion of the first substrate W1 by abutting against the central portion of the first substrate W1 by the air supplied from the electro-pneumatic regulator. Further, the front end portion of the actuator part 192 is inserted into the through hole 176 by the air from the electro-pneumatic regulator and can move up and down freely in the vertical direction.

[0072] The actuator unit 192 is supported by the linear motion mechanism 193. The linear motion mechanism 193 moves the actuator unit 192 in the vertical direction by a drive unit having a motor built therein, for example.

[0073] The plunger 190 is configured as described above. The movement of the actuator unit 192 is controlled by the linear motion mechanism 193, and the pressing load of the pressing pin 191 against the first substrate W1 is controlled by the actuator unit 192. Thus, the plunger 190 presses the central portion of the first substrate W1 adsorbed and held by the first holding unit 140 to bring the central portion of the first substrate W1 into contact with the second substrate W2.

[0074] A plurality of pins 171 that contact the upper surface (non-bonding surface W1n) of the first substrate W1 are provided on the lower surface 170a of the main body portion 170. The plurality of pins 171 have a diameter size of, for example, 0.1 mm to 1 mm and a height of several tens of μm to several hundreds of μm. The plurality of pins 171 are arranged at intervals of, for example, 2 mm.

[0075] The first holding unit 140 includes a plurality of outer adsorption portions 301, inner adsorption portions 302, and a negative pressure forming portion 320, which will be described later, in a part of the region where the plurality of pins 171 are provided. In the present embodiment, the plurality of outer adsorption portions 301 and the negative pressure forming portion 320 are arranged according to the anisotropy of the physical properties of the first substrate W1.

[0076] Here, Figures 7 to 9 the outer adsorption portion 301, the inner adsorption portion 302, and the negative pressure forming portion 320 included in the first holding unit 140 will be described. Figure 7 and Figure 8 is a schematic diagram showing an example of the case where the bonding region is enlarged. Figure 9 is a schematic diagram obtained by observing the first holding unit 140 from below the first holding unit 140. In addition, a negative Miller index is usually expressed by adding a "-" (bar) above the number, but in this specification, it is expressed by adding a negative sign before the number.

[0077] As Figure 7 shown, the first substrate W1 and the second substrate W2 are single crystal silicon wafers having a crystal direction of

[100] in a direction perpendicular to the surface (bonding surface). The cut portions N of the first substrate W1 and the second substrate W2 are formed at the outer edges in the

[011] crystal direction of the first substrate W1 and the second substrate W2. In addition, the diameters of the first substrate W1 and the second substrate W2 are, for example, 300 mm.

[0078] When the central portion of the first substrate W1 is pressed so that the central portion of the first substrate W1 comes into contact with the central portion of the second substrate W2, the central portions of the first substrate W1 and the second substrate W2 are joined by intermolecular forces, and thus a joining region A is formed at the central portions of the two substrates. Thereafter, a joining wave in which the joining region A expands from the central portions of the two substrates toward the outer peripheral portions is generated, so that the joining surfaces W1j and W2j of the first substrate W1 and the second substrate W2 are joined to each other over the entire surface.

[0079] Assume that in the case where the first substrate W1 is held using a holding portion that holds the entire outer edge of the first substrate W1 and the above-described joining process is performed, the joining region A expands unevenly rather than in a concentric circle shape.

[0080] Specifically, as Figure 8 shown, the joining region A expands faster in the 45-degree direction than in the 90-degree direction. The 90-degree direction refers to the direction of a 90-degree cycle when the direction from the central portion of the first substrate W1 toward the [0-11] crystal direction parallel to the surface of the first substrate W1 is used as a reference ( Figure 8 the directions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees shown). The 45-degree direction refers to the direction of a 90-degree cycle when the direction from the central portion of the first substrate W1 toward the

[010] crystal direction parallel to the surface of the first substrate W1 is used as a reference ( Figure 8 the directions of 45 degrees, 135 degrees, 225 degrees, and 315 degrees shown). As a result, the shape of the joining region A, which is initially circular, gradually approaches a quadrilateral with the 45-degree direction as its vertex as it expands. In this way, the joining speed between the substrates is faster in the region of the 45-degree direction and slower in the region of the 90-degree direction than in the region of the 45-degree direction.

[0081] As a cause thereof, anisotropy in physical properties such as the Young's modulus of the first substrate W1 and the second substrate W2 can be considered.

[0082] For example, the values of the Young's modulus, Poisson's ratio, and shear elastic coefficient of a single-crystal silicon wafer change in a 90-degree cycle. Specifically, the Young's modulus of a single-crystal silicon wafer is the highest in the 90-degree direction and the lowest in the 45-degree direction. In addition, Poisson's ratio and the shear elastic coefficient are the highest in the 45-degree direction and the lowest in the 90-degree direction.

[0083] In this way, since the physical properties such as the Young's modulus of the single-crystal silicon wafer are anisotropic, the distribution of stress / strain applied to the first substrate W1 is a non-uniform distribution rather than a concentric circle shape. Moreover, it is considered that this non-uniform distribution causes the joining region A to expand unevenly, which may deteriorate the strain of the superposed substrates T and thus reduce the joining accuracy between the substrates.

[0084] Therefore, in this embodiment, the negative pressure forming unit 320 is used to form negative pressure in the space between the lower surface 170a of the main body 170 and the upper surface W1n of the first substrate W1, thereby appropriately suppressing the bonding speed between the substrates and improving the bonding accuracy between the substrates.

[0085] In addition, in this embodiment, instead of holding the entire periphery of the first substrate W1, the first holding portion 140 is used to hold the area in the 45-degree direction where the bonding area A expands fastest on the periphery of the first substrate W1, thereby improving the bonding accuracy between the substrates.

[0086] First, the outer suction unit 301 and the inner suction unit 302 are described. Figure 9 As shown, the lower surface 170a of the main body 170 in the first holding portion 140 is provided with an outer suction portion 301 and an inner suction portion 302 for vacuum suctioning the first substrate W1. There are a plurality of outer suction portions 301 (for example, 16), and there is one inner suction portion 302. In addition, the outer suction portion 301 and the inner suction portion 302 have the same height as the pin 171.

[0087] The plurality of outer adsorption parts 301 each have an adsorption area that is in an arc shape when viewed from above. The plurality of outer adsorption parts 301 are arranged in a circumferential direction relative to the outer periphery of the main body 170. Specifically, the plurality of outer adsorption parts 301 are arranged at intervals of 90 degrees, and include a group of two first outer adsorption parts 311, and a group of two second outer adsorption parts 312 that are arranged 45 degrees apart in the circumferential direction relative to a group of first outer adsorption parts 311. That is, the plurality of outer adsorption parts 301 include four groups of first outer adsorption parts 311 and four groups of second outer adsorption parts 312.

[0088] The four sets of first outer suction parts 311 and the four sets of second outer suction parts 312 suction and hold the outer periphery of the first substrate W1. The outer periphery of the first substrate W1 is a portion within 15% of the radius of the first substrate W1 from the outer periphery end of the first substrate W1.

[0089] Four sets of first outer suction parts 311 are arranged in the 45-degree direction of the first substrate W1. Specifically, the four sets of first outer suction parts 311 are arranged at positions where the center between adjacent arc-shaped suction areas coincides with the 45-degree direction of the first substrate W1. In addition, four sets of second outer suction parts 312 are arranged in the 90-degree direction of the first substrate W1. Specifically, the four sets of second outer suction parts 312 are arranged at positions where the center between adjacent arc-shaped suction areas coincides with the 90-degree direction of the first substrate W1.

[0090] Four sets of first outer suction portions 311 are connected to a single first vacuum pump 171b via a first suction pipe 171a, and the first substrate W1 is adsorbed by vacuum suction based on the first vacuum pump 171b. In addition, four sets of second outer suction portions 312 are connected to a single second vacuum pump 172b via a second suction pipe 172a, and the first substrate W1 is adsorbed by vacuum suction based on the second vacuum pump 172b. Here, for easy understanding, only the piping structure of any one of the plurality of first outer suction portions 311 is shown. The same applies to the plurality of second outer suction portions 312.

[0091] Thus, when the direction from the central portion of the first substrate W1 toward the [0-11] crystal direction parallel to the surface of the first substrate W1 is defined as 0 degrees, the four sets of first outer suction portions 311 are arranged at intervals of 90 degrees with a 45-degree direction as a reference. In addition, the four sets of second outer suction portions 312 are arranged at intervals of 90 degrees with a 0-degree direction as a reference.

[0092] The inner suction portion 302 has a suction area that is circular in plan view. The inner suction portion 302 is disposed at a position radially inward of the outer suction portion 301 with respect to the main body portion 170. In addition, the inner suction portion 302 is disposed at a position radially outward of the through hole 176 through which the pressing pin 191 (see Figure 6 ) of the collision pin 190 is inserted. The inner suction portion 302 is connected to a single third vacuum pump 173b via a third suction pipe 173a, and the first substrate W1 is adsorbed by vacuum suction based on the third vacuum pump 173b. In addition, in the present embodiment, an example in which the inner suction portion 302 is one is shown, but it is not limited thereto, and the inner suction portion 302 may also be plural.

[0093] Next, Figure 6 and Figure 9 will be referred to for an explanation of the negative pressure forming portion 320. As Figure 6 and Figure 9 shown, the negative pressure forming portion 320 includes a suction port 331, a suction side groove portion 431, a supply port 340 (see Figure 9 ) and a supply side groove portion 440 (see Figure 9 ).

[0094] There are a plurality of (e.g., 16) suction ports 331 disposed on the lower surface 170a of the main body portion 170. The plurality of suction ports 331 are circumferentially arranged near the outer peripheral portion of the main body portion 170 and at a position radially inward of the outer suction portion 301. Specifically, the plurality of suction ports 331 are arranged at intervals of 90 degrees, and include a first suction port 331a in a group of two, and a second suction port 331b in a group of two that is circumferentially offset by 45 degrees with respect to a group of the first suction ports 331a. That is, the plurality of suction ports 331 include four groups of the first suction ports 331a and four groups of the second suction ports 331b.

[0095] The four groups of the first suction ports 331a and the four groups of the second suction ports 331b are openings for sucking gas (e.g., air, gas). In the present embodiment, by sucking this gas, a negative pressure is formed in the space between the lower surface 170a of the main body portion 170 and the upper surface W1n of the first substrate W1, which will be described later.

[0096] The four groups of the first suction ports 331a are arranged in the 45-degree direction of the first substrate W1. Specifically, the four groups of the first suction ports 331a are arranged at positions where the center between adjacent first suction ports 331a coincides with the 45-degree direction of the first substrate W1. In addition, the four groups of the second suction ports 331b are arranged in the 90-degree direction of the first substrate W1. Specifically, the four groups of the second suction ports 331b are arranged at positions where the center between adjacent second suction ports 331b coincides with the 90-degree direction of the first substrate W1.

[0097] The four groups of the first suction ports 331a are connected to a single first suction pump 174b via a suction pipe 174a, and the gas near the first suction ports 331a is sucked by the operation of the first suction pump 174b. In addition, the four groups of the second suction ports 331b are connected to a single second suction pump 175b via a suction pipe 175a, and the gas near the second suction ports 331b is sucked by the operation of the second suction pump 175b. Here, for easy understanding, only the piping structure of any one of the plurality of first suction ports 331a is shown. The same applies to the plurality of second suction ports 331b.

[0098] In addition, the number and arrangement of the above-described first to third vacuum pumps 171b to 173b and the first and second suction pumps 174b and 175b are not particularly limited. The first to third vacuum pumps 171b to 173b and the first and second suction pumps 174b and 175b may be provided in respective regions where the adsorption pressure and the suction force are independently controlled.

[0099] The above-described suction port 331 (the first suction port 331a or the second suction port 331b) is provided in the suction-side groove portion 431. Thus, like the suction port 331, the suction-side groove portion 431 is provided in plurality (for example, 16). Specifically, the suction-side groove portion 431 is formed in the lower surface 170a of the main body portion 170. The suction-side groove portion 431 is formed at a position radially inside the outer adsorption portion 301 and radially outside the inner adsorption portion 302. The suction-side groove portion 431 is a groove portion that is long and strip-shaped in a plan view, and is formed such that its long side direction extends in the radial direction on the lower surface 170a of the main body portion 170. In other words, the suction-side groove portion 431 is formed radially from the central portion of the lower surface 170a of the main body portion 170 toward the outer peripheral portion.

[0100] As Figure 6 shown, the suction port 331 is a radially outer portion of the suction-side groove portion 431 and is provided in the concave portion (the upper surface in Figure 6 ) 431a. In this way, since the suction port 331 is formed in the suction-side groove portion 431, it does not come into direct contact with the first substrate W1. Further, the suction-side groove portion 431 is formed such that the concave portion (the upper surface in Figure 6 ) 431a is conical. Specifically, the suction-side groove portion 431 is formed such that the depth becomes shallower as it goes from the radially outer side toward the radially inner side.

[0101] Further, in the suction-side groove portion 431, the radially inner end side is set at a height position lower than the pin 171, and thus it is in an open state and does not come into direct contact with the first substrate W1. Therefore, the suction port 331 does not adsorb and hold the first substrate W1 by suction, but is not limited thereto, and may be configured to adsorb and hold the first substrate W1.

[0102] The arrangement position of the suction-side groove portion 431 will be described in detail. As Figure 9 shown, the suction-side groove portion 431 provided with the first suction port 331a is arranged in the 45-degree direction of the first substrate W1. Specifically, the suction-side groove portion 431 provided with the first suction port 331a is arranged at a position where the center between adjacent suction-side groove portions 431 coincides with the 45-degree direction of the first substrate W1. Further, the suction-side groove portion 431 provided with the second suction port 331b is arranged in the 90-degree direction of the first substrate W1. Specifically, the suction-side groove portion 431 provided with the second suction port 331b is arranged at a position where the center between adjacent suction-side groove portions 431 coincides with the 90-degree direction of the first substrate W1.

[0103] There are a plurality of (e.g., eight) air supply ports 340, which are arranged on the lower surface 170a of the main body 170. The plurality of air supply ports 340 are arranged circumferentially at a position near the outer peripheral portion of the main body 170 and radially inside the outer suction portion 301. For example, the air supply ports 340 are arranged circumferentially in the same circumferential direction as the circle where the suction ports 331 are arranged.

[0104] Specifically, the plurality of air supply ports 340 are arranged at an interval of 45 degrees and are arranged between a set of first suction ports 331a and a set of second suction ports 331b. Specifically, the plurality of air supply ports 340a are arranged between the 45-degree direction and the 90-degree direction of the first substrate W1. In other words, the plurality of air supply ports 340 are arranged between a first negative pressure region 501 including a set of first suction ports 331a and a second negative pressure region 502 including a set of second suction ports 331b (both will be described later. Refer to Figure 11 )

[0105] The air supply port 340 is configured to penetrate the main body 170 and communicate with the atmospheric pressure space (external space). Therefore, when the suction operation starts through the above-described suction port 331, the gas from the atmospheric pressure space flows in (is supplied) through the air supply port 340.

[0106] The air supply port 340 is provided in the air supply side groove portion 440. Therefore, like the air supply port 340, the air supply side groove portion 440 is also plural (e.g., eight). Specifically, the air supply side groove portion 440 is formed on the lower surface 170a of the main body 170. The air supply side groove portion 440 is formed at a position radially inside the outer suction portion 301 and radially outside the inner suction portion 302. The air supply side groove portion 440 is a groove portion that is long and strip-shaped in a plan view, and is formed such that its long side direction extends radially on the lower surface 170a of the main body 170. In other words, the air supply side groove portion 440 is formed radially from the center portion of the lower surface 170a of the main body 170 toward the outer peripheral portion.

[0107] The air supply port 340 is the radially outer part of the air supply side groove portion 440 and is provided in the concave portion 440a. Thus, since the air supply port 340 is formed in the air supply side groove portion 440, it does not directly contact the first substrate W1. In addition, although not shown, the air supply side groove portion 440 is formed such that its depth is fixed or substantially fixed from the radially outer side to the radially inner side.

[0108] The arrangement position of the air supply side groove portion 440 will be described in detail. As Figure 9 shown, the air supply side groove portion 440 is arranged between the suction side groove portion 431 provided with the first suction port 331a and the suction side groove portion 431 provided with the second suction port 331b. Specifically, the air supply side groove portion 440 is arranged between the 45-degree direction and the 90-degree direction of the first substrate W1.

[0109] Next, the formation of negative pressure by the negative pressure forming unit 320 will be described. As described above, the negative pressure forming unit 320 forms a negative pressure in the space B (see Figure 13 ) between the lower surface 170a of the main body 170 and the upper surface W1n of the first substrate W1. This space B is a space formed when the center portion of the first substrate W1 held and adsorbed by the first holding portion 140 is pressed by the ejector pin 190 to bring the center portion of the first substrate W1 into contact with the second substrate W2, causing the first substrate W1 to separate from the main body 170.

[0110] Here, with reference to Figure 10 and Figure 11 , the formation of negative pressure will be described in detail. Figure 10 is a schematic perspective view showing the lower surface 170a side of the main body 170 enlarged. Figure 11 is a schematic view obtained by observing the first holding portion 140 from below the first holding portion 140. In addition, in Figure 10 , Figure 11 , for ease of understanding, the illustration of the first substrate W1 held and adsorbed by the first holding portion 140 is omitted. Additionally, in Figure 10 , Figure 11 , the flow of gas is indicated by arrows, and the length of the arrows represents the velocity (flow rate) of the gas flow. Specifically, it shows that the flow rate increases as the arrows become longer.

[0111] As shown in Figure 10 and Figure 11 , the negative pressure forming unit 320 according to the present embodiment forms a negative pressure in the space B by generating a gas flow along the lower surface 170a of the main body 170.

[0112] Specifically, when the suction operation using the suction port 331 is started by driving the first suction pump 174b and the second suction pump 175b (see Figure 9 ), as shown in Figure 10 , gas from the atmospheric pressure space flows in through the air supply port 340. The gas flowing in through the air supply port 340 flows in the air supply side groove portion 440 and then flows toward an adjacent suction side groove portion 431 among the plurality of suction side groove portions 431 provided with the suction port 331. That is, the gas flowing in through the air supply port 340 flows out of the air supply side groove portion 440 and flows along the lower surface 170a of the main body 170. At this time, the gas flows in a circumferential direction along the lower surface 170a of the main body 170. The gas flowing along the lower surface 170a of the main body 170 flows into the suction side groove portion 431. The gas flowing into the suction side groove portion 431 is sucked and discharged from the suction port 331.

[0113] In this way, the negative pressure forming portion 320 generates a gas that flows along the lower surface 170a of the main body portion 170. By generating the flow of this gas (i.e., generating an air current), a negative pressure is generated in the space B between the lower surface 170a of the main body portion 170 and the upper surface W1n of the first substrate W1, and thus a force F in the vertically upward direction is applied to the first substrate W1 (refer to Figure 13 ). Thereby, the speed of the bonding between the substrates is appropriately suppressed, which will be described later.

[0114] In addition, in the present embodiment, by making the negative pressure formed in the region in the 45-degree direction where the bonding speed is the fastest different from the negative pressure formed in the region in the 90-degree direction where the bonding speed is the slowest, the bonding region A (refer to Figure 7 ) has expanded in a state approaching a concentric circle.

[0115] Next, as Figure 11 shown, when the direction from the central portion of the first substrate W1 toward the [0-11] crystal direction parallel to the surface of the first substrate W1 is defined as 0 degrees, the region set at intervals of 90 degrees with the 45-degree direction as a reference, that is, the region in the 45-degree direction, is referred to as the "first negative pressure region 501". In addition, the region set at intervals of 90 degrees with the 0-degree direction as a reference, that is, the region in the 90-degree direction, is referred to as the "second negative pressure region 502". In addition, in Figure 11 , for easy understanding, the first negative pressure region 501 is indicated by a single dotted line, and the second negative pressure region 502 is indicated by a double dotted line.

[0116] The negative pressure forming portion 320 according to the present embodiment makes the negative pressure in the first negative pressure region 501 different from the negative pressure in the second negative pressure region 502. Specifically, the negative pressure forming portion 320 makes the negative pressure in the first negative pressure region 501 greater than the negative pressure in the second negative pressure region 502.

[0117] When specifically described, the above-mentioned first suction port 331a is provided in the first negative pressure region 501. A second suction port 331b is provided in the second negative pressure region 502. Moreover, the suction force from the first suction port 331a and the suction force from the second suction port 331b are set to be different from each other. Specifically, it is set that the suction force from the first suction port 331a is greater than the suction force from the second suction port 331b.

[0118] Thus, the flow velocity of the gas flowing from the gas supply port 340 and the gas supply side groove portion 440 to the first suction port 331a and the suction side groove portion 431 of the first suction port 331a is faster than the flow velocity of the gas flowing to the second suction port 331b and the suction side groove portion 431 of the second suction port 331b. Therefore, the negative pressure in the first negative pressure region 501 where the flow velocity of the gas is fast is greater than the negative pressure in the second negative pressure region 502 where the flow velocity of the gas is slower compared to the first negative pressure region 501.

[0119] Therefore, in the first negative pressure region 501, due to the large negative pressure, the force F acting on the first substrate W1 (refer to Figure 13 ) also becomes larger. Thus, in the region in the 45-degree direction where the bonding speed is the fastest, the bonding speed is suppressed to a greater extent. On the other hand, in the second negative pressure region 502, the negative pressure is smaller compared to the first negative pressure region 501. Therefore, the force F acting on the first substrate W1 (refer to Figure 13 ) is also smaller compared to the first negative pressure region 501. Therefore, in the second negative pressure region 502, in the region in the 90-degree direction where the bonding speed is the slowest, the bonding speed is suppressed to a smaller extent.

[0120] In this way, by using different negative pressures to suppress the bonding speed in the first negative pressure region 501 and the second negative pressure region 502, the bonding region A (refer to Figure 7 ) can be expanded in a state close to a concentric circle (refer to Figure 15 ) described later.

[0121] In addition, in the first negative pressure region 501 and the second negative pressure region 502, negative pressures are also formed in the regions 501a and 502a between the adjacent suction side groove portions 431. Specifically, the regions 501a and 502a are located between the suction side groove portions 431 and are not adjacent to the gas supply side groove portion 440. Therefore, they are regions where gas is difficult to flow. However, since the gas flows around the regions 501a and 502a, negative pressure walls are formed around the regions 501a and 502a, and thus negative pressures are also formed in the regions 501a and 502a surrounded by the negative pressure walls. In this way, by arranging a plurality of suction side groove portions 431 adjacent to each other, it is possible to ensure that the regions where negative pressure is formed (here, the regions 501a and 502a) are relatively large.

[0122] In addition, in the suction side groove portion 431 provided with the suction port 331, the attractive force may decrease as it moves away from the suction port 331. Therefore, in the suction side groove portion 431 according to the present embodiment, as described above, the suction port 331 is provided on the radially outer side and is formed to be shallower as it goes from the radially outer side to the radially inner side (refer to Figure 6)。In this way, in the present embodiment, as the distance from the suction port 331 increases, the depth of the suction-side groove portion 431 becomes shallower. Therefore, the flow velocity at a position far from the suction port 331 (here, near the radial inner side) can be increased, and thus the decrease in the suction force can be suppressed. As a result, gas with a uniform flow velocity as much as possible can flow in the radial direction on the lower surface 170a of the main body portion 170, and thus a negative pressure can be uniformly formed.

[0123] Continue Figure 9 Continuing the description, the main body portion 170 is provided with a detection unit 350 for detecting the bonding state of the first substrate W1 and the second substrate W2. As an example of the detection unit 350, a distance sensor for detecting the distance from the lower surface 170a of the main body portion 170 to the upper surface W1n of the first substrate W1 can be used. In addition, as the distance sensor, sensors of various types such as optical, capacitance, radio wave, and ultrasonic wave types can be used.

[0124] The detection units 350 are arranged in the radial direction on the lower surface 170a of the main body portion 170. When the first substrate W1 is bonded to the second substrate W2, the bonding is performed in the radial direction from the central portion toward the outer peripheral portion. Therefore, by arranging the detection units 350 in the radial direction, it is possible to monitor to which position the bonding between the first substrate W1 and the second substrate W2 has progressed.

[0125] The detection unit 350 according to the present embodiment is provided between adjacent suction-side groove portions 431. In other words, in the present embodiment, by arranging a plurality of suction-side groove portions 431 adjacent to each other, a space is formed between the adjacent suction-side groove portions 431 in a plan view, and the detection unit 350 is provided in this space. In this way, in the present embodiment, by arranging a plurality of suction-side groove portions 431 adjacent to each other, it is possible to easily secure a space for providing the detection unit 350.

[0126] In addition, although an example in which the detection unit 350 is a distance sensor is shown above, it is not limited thereto. As long as the bonding state of the first substrate W1 and the second substrate W2 can be detected, other types of sensors or the like can also be used.

[0127] Return Figure 6 The second holding portion 141 will be described. The second holding portion 141 has a main body portion 200 having a diameter equal to or larger than the diameter of the second substrate W2. Here, the second holding portion 141 having a diameter larger than the diameter of the second substrate W2 is shown. The upper surface of the main body portion 200 is a facing surface facing the lower surface (non-bonding surface W2n) of the second substrate W2.

[0128] On the upper surface of the main body 200, a plurality of pins 201 are provided which contact the lower surface (non-bonding surface Wn2) of the second substrate W2. The plurality of pins 201 have a diameter size of, for example, 0.1 mm to 1 mm and a height of several tens of μm to several hundreds of μm. The plurality of pins 201 are arranged uniformly at an interval of, for example, 2 mm.

[0129] In addition, on the upper surface of the main body 200, a lower rib 202 is provided annularly outside the plurality of pins 201. The lower rib 202 is formed in an annular shape and supports the outer peripheral portion of the second substrate W2 throughout the entire circumference.

[0130] In addition, the main body 200 has a plurality of lower suction ports 203. A plurality (three in this case) of the plurality of lower suction ports 203 are provided in the suction area surrounded by the lower rib 202. The plurality of lower suction ports 203 are connected to a suction device (not shown) such as a vacuum pump via a suction tube (not shown).

[0131] The second holding portion 141 decompresses the suction area by performing vacuum suction on the suction area surrounded by the lower rib 202 from the plurality of lower suction ports 203. Thus, the second substrate W2 placed on the suction area is adsorbed and held by the second holding portion 141.

[0132] Since the lower rib 202 supports the outer peripheral portion of the lower surface of the second substrate W2 throughout the entire circumference, the second substrate W2 is properly vacuum-sucked up to the outer peripheral portion. Thus, the entire surface of the second substrate W2 can be adsorbed and held. In addition, since the lower surface of the second substrate W2 is supported by the plurality of pins 201, the second substrate W2 is easily peeled off from the second holding portion 141 when the vacuum suction of the second substrate W2 is released.

[0133] Next, with reference to Figures 12 to 14 the specific operation of the bonding system 1 according to the embodiment will be described. Figure 12 is a flowchart showing a part of the processing executed by the bonding system 1 according to the embodiment. In addition, Figure 13 and Figure 14 are operation explanatory diagrams of the bonding process. Various processes shown in Figure 12 are executed based on the control of the control device 70.

[0134] First, a cassette C1 containing a plurality of first substrates W1, a cassette C2 containing a plurality of second substrates W2, and an empty cassette C3 are placed on a specified mounting plate 11 of the loading / unloading station 2. Then, the first substrate W1 in the cassette C1 is taken out by the transfer device 22 and transferred to the transfer device 50 of the third processing block G3 of the processing station 3.

[0135] Next, the first substrate W1 is transported to the surface modification device 30 of the first processing block G1 by the transport device 61. In the surface modification device 30, oxygen as a processing gas is excited in a prescribed reduced-pressure atmosphere to be ionized into plasma. This oxygen ion is irradiated onto the bonding surface W1j of the first substrate W1 to perform plasma processing on the bonding surface W1j. Thereby, the bonding surface W1j of the first substrate W1 is modified (step S101).

[0136] Next, the first substrate W1 is transported to the surface hydrophilization device 40 of the second processing area G2 by the transport device 61. In the surface hydrophilization device 40, while the first substrate W1 held by the rotary holding disk is rotated, pure water is supplied onto the first substrate W1. Then, the supplied pure water diffuses on the bonding surface W1j of the first substrate W1, and hydroxyl groups (silanol groups) adhere to the bonding surface W1j of the first substrate W1 modified in the surface modification device 30 to hydrophilize the bonding surface W1j. In addition, the bonding surface W1j of the first substrate W1 is cleaned with this pure water (step S102).

[0137] Next, the first substrate W1 is transported to the bonding device 41 of the second processing block G2 by the transport device 61. The first substrate W1 transported into the bonding device 41 is transported to the position adjustment mechanism 120 via the transfer unit 110 by the substrate transport mechanism 111. Then, the orientation of the first substrate W1 in the horizontal direction is adjusted by the position adjustment mechanism 120 (step S103).

[0138] After that, the first substrate W1 is handed over from the position adjustment mechanism 120 to the holding arm 131 of the flipping mechanism 130. Next, in the transport area T1, the front and back surfaces of the first substrate W1 are flipped by flipping the holding arm 131 (step S104). That is, the bonding surface W1j of the first substrate W1 is oriented downward.

[0139] After that, the holding arm 131 of the flipping mechanism 130 rotates and moves below the first holding unit 140. Then, the first substrate W1 is handed over from the flipping mechanism 130 to the first holding unit 140. The non-bonding surface W1n of the first substrate W1 is adsorbed and held by the first holding unit 140 in a state where the notch portion N is oriented in a predetermined direction, that is, the direction where the second outer adsorption portion 312 is provided (step S105).

[0140] In step S105, the first holding unit 140 adsorbs and holds the first substrate W1 using all of the plurality of outer adsorption portions 301 and inner adsorption portions 302.

[0141] While the first substrate W1 is being processed in the above-described steps S101 to S105, the second substrate W2 is processed. First, the transfer device 22 takes out the second substrate W2 in the cassette C2 and transfers it to the transfer device 50 of the processing station 3.

[0142] Next, the transfer device 61 transfers the second substrate W2 to the surface modification device 30 to modify the bonding surface W2j of the second substrate W2 (step S106). The modification of the bonding surface W2j of the second substrate W2 in step S106 is the same as that in step S101 described above.

[0143] After that, the transfer device 61 transfers the second substrate W2 to the surface hydrophilic treatment device 40 to hydrophilize the bonding surface W2j of the second substrate W2 and clean the bonding surface W2j (step S107). The hydrophilization and cleaning of the bonding surface W2j of the second substrate W2 in step S107 are the same as those in step S102.

[0144] After that, the transfer device 61 transfers the second substrate W2 to the bonding device 41. The second substrate W2 carried into the bonding device 41 is transferred to the position adjustment mechanism 120 via the transfer unit 110 by the substrate transfer mechanism 111. Then, the position adjustment mechanism 120 adjusts the orientation of the second substrate W2 in the horizontal direction (step S108).

[0145] After that, the substrate transfer mechanism 111 transfers the second substrate W2 to the second holding unit 141 and adsorbs and holds it on the second holding unit 141 (step S109). The non-bonding surface W2n of the second substrate W2 is adsorbed and held by the second holding unit 141 in a state where the cut portion N faces a predetermined direction, specifically, the same direction as the cut portion N of the first substrate W1.

[0146] Next, the horizontal position adjustment of the first substrate W1 held by the first holding unit 140 and the second substrate W2 held by the second holding unit 141 is performed (step S110).

[0147] Next, the vertical position adjustment of the first substrate W1 held by the first holding unit 140 and the second substrate W2 held by the second holding unit 141 is performed (step S111). Specifically, the first moving unit 160 moves the second holding unit 141 upward in the vertical direction, thereby bringing the second substrate W2 closer to the first substrate W1. As a result, the distance between the bonding surface W2j of the second substrate W2 and the bonding surface W1j of the first substrate W1 is adjusted to a predetermined distance, for example, 50 μm to 200 μm.

[0148] Next, after releasing the adsorption and holding of the first substrate W1 by the inner adsorption portion 302 and the plurality of second outer adsorption portions 312 (step S112), the central portion of the first substrate W1 is pressed down by lowering the pressing pin 191 of the ejector pin 190 (step S113). Until immediately before the first substrate W1 is pressed down by the ejector pin 190, the central portion of the first substrate W1 is adsorbed and held by the inner adsorption portion 302, thereby suppressing the self-weight deflection (e.g., about 1 μm) of the central portion of the first substrate W1.

[0149] When the central portion of the first substrate W1 comes into contact with the central portion of the second substrate W2 and the central portions of the first substrate W1 and the second substrate W2 are pressed by the ejector pin 190 with a predetermined force, bonding starts between the pressed central portions of the first substrate W1 and the second substrate W2. That is, since the bonding surfaces W1j of the first substrate W1 and W2j of the second substrate W2 have been modified in steps S101 and S106, respectively, first, van der Waals forces (intermolecular forces) are generated between the bonding surfaces W1j and W2j, and the bonding surfaces W1j and W2j are bonded to each other. And, since the bonding surfaces W1j of the first substrate W1 and W2j of the second substrate W2 have been hydrophilized in steps S102 and S107, respectively, the hydrophilic groups between the bonding surfaces W1j and W2j form hydrogen bonds, so that the bonding surfaces W1j and W2j are firmly bonded to each other. By doing so, a bonding region A is formed (refer to Figure 7 ).

[0150] After that, a bonding wave in which the bonding region A expands from the central portions of the first substrate W1 and the second substrate W2 toward the outer peripheral portions is generated between the first substrate W1 and the second substrate W2 (refer to Figure 8 ).

[0151] In addition, when the lower surface 170a of the main body portion 170 is separated from the upper surface W1n of the first substrate W1 by pressing the ejector pin 190, a negative pressure is formed in the space B between the separated lower surface 170a of the main body portion 170 and the upper surface W1n of the first substrate W1 (step S114). Thereby, the speed of bonding between the substrates can be appropriately suppressed, and the bonding accuracy between the substrates can be improved.

[0152] Specifically, the control device 70 drives the first suction pump 174b and the second suction pump 175b to start a suction operation through the suction ports 331 (specifically, the first suction port 331a and the second suction port 331b). Thereby, the gas flowing in from the gas supply port 340 and the like flows on the lower surface 170a of the main body portion 170. By generating this gas flow, a negative pressure is generated in the space B between the lower surface 170a of the main body portion 170 and the upper surface W1n of the first substrate W1, and thus a force F in the vertically upward direction acts on the first substrate W1.

[0153] In the present embodiment, the negative pressure in the first negative pressure region 501, which is the region in the 45° direction where the expansion of the bonding region A is the fastest, is greater than the negative pressure in the second negative pressure region 502, which is the region in the 90° direction where the expansion of the bonding region A is the slowest.

[0154] Here, reference is also made to Figure 15 to describe the expansion of the bonding region A in the case where the negative pressure is formed as described above. Figure 15 It is a schematic diagram showing an example of the expansion of the bonding region A in the bonding device 41 according to the present embodiment. In addition, in Figure 15 , for ease of understanding, the positions of the first negative pressure region 501 and the second negative pressure region 502 are shown. In addition, in Figure 15 , for ease of understanding, the expansion of the bonding region in the case where no negative pressure is formed, that is, Figure 8 the expansion of the bonding region shown, is indicated by a dotted line and marked with A1.

[0155] As Figure 15 shown, in the first negative pressure region 501, since the negative pressure is large, the force F acting on the first substrate W1 (refer to Figure 13 ) also becomes large. Therefore, in the first negative pressure region 501 in the 45-degree direction where the bonding speed is the fastest, the bonding speed is suppressed to a large extent. In the second negative pressure region 502, since the negative pressure is smaller than that in the first negative pressure region 501, the force F acting on the first substrate W1 is also smaller than that in the first negative pressure region 501. Therefore, in the second negative pressure region 502 in the 90-degree direction where the bonding speed is the slowest, the bonding speed is suppressed to a smaller extent. As a result, compared with the bonding region A1 in the case where no negative pressure is formed, the bonding region A can be expanded in a state close to a concentric circle, thereby improving the bonding accuracy between the substrates.

[0156] In addition, for example, an attracting operation through the suction port 331 as shown in Figure 13 is performed from before the start of pressing the plunger 190 until the bonding between the substrates is completed, but it is not limited thereto. That is, the attracting operation may also be performed through the suction port 331 after the start of pressing the plunger 190. In addition, the attracting operation through the suction port 331 may also be ended before the bonding between the substrates is completed. That is, the start and end times of the attracting operation through the suction port 331 can be arbitrarily set.

[0157] In addition, in the bonding device 41 according to the present embodiment, only the first outer suction portion 311 disposed in the 45° direction in which the bonding region A expands fastest among the plurality of outer suction portions 301 arranged according to the anisotropy of the first substrate W1 is used to suck and hold the first substrate W1. In other words, the first substrate W1 is not sucked and held in the 90° direction in which the expansion of the bonding region A is slowest.

[0158] Accordingly, compared with the case of sucking and holding the entire circumference of the outer edge of the first substrate W1, the non-uniformity of the stress / strain distribution applied to the first substrate W1 can be alleviated. As a result, the non-uniformity of the bonding wave is alleviated, and the bonding region A expands in a state close to a concentric circle. Thus, the bonding device 41 according to the present embodiment can reduce the strain (distortion) of the overlapping substrate T caused by anisotropy, and thereby can improve the bonding accuracy between the substrates.

[0159] After that, the suction and holding of the first substrate W1 by the first outer suction portion 311 is released (step S115). As a result, the outer peripheral portion of the first substrate W1 in the 45-degree direction sucked and held by the first outer suction portion 311 drops. As a result, as Figure 14 shown, the bonding surface W1j of the first substrate W1 and the bonding surface W2j of the second substrate W2 are in contact with each other over the entire surface, thereby forming an overlapping substrate T.

[0160] After that, the pressing pin 191 is raised to the first holding portion 140 to release the suction and holding of the second substrate W2 by the second holding portion 141. After that, the overlapping substrate T is transported to the transfer device 51 by the transport device 61, and then the overlapping substrate T is transported to the cassette C3 by the transport device 22 of the loading / unloading station 2. Through this, a series of bonding processes are completed.

[0161] As described above, the bonding device 41 according to the present embodiment includes a first holding portion 140, a second holding portion 141, and a knock pin 190. The first holding portion 140 sucks and holds the first substrate W from above the first substrate W1. The second holding portion 141 is disposed at a position lower than the first holding portion 140 and sucks and holds the second substrate W2 from below the second substrate W2. The knock pin 190 presses the central portion of the first substrate W1 to bring the central portion of the first substrate W1 into contact with the second substrate W2. In addition, the first holding portion 140 includes a main body portion 170 and a negative pressure forming portion 320. The main body portion 170 has a lower surface 170a facing the first substrate W1. The negative pressure forming portion 320 is used to form a negative pressure in the space B between the lower surface 170a of the main body portion 170 separated by pressing the knock pin 190 and the upper surface W1n of the first substrate W1. Thereby, the bonding accuracy between the substrates can be improved.

[0162] In addition, the negative pressure forming portion 320 generates a gas flow along the lower surface 170a of the main body portion 170, thereby forming a negative pressure in the space B. Thus, a negative pressure can be reliably formed in the space B.

[0163] In addition, the negative pressure forming portion 320 forms a negative pressure in the space B by generating a gas flow along the circumferential direction on the lower surface 170a of the main body portion 170. Thus, a negative pressure can be formed in a relatively large area having a shape along the circumferential direction of the lower surface 170a of the main body portion 170.

[0164] In addition, the negative pressure forming portion 320 includes a suction port 331 and a suction side groove portion 431. The suction port 331 is provided in the suction side groove portion 431, and the suction side groove portion 431 extends radially along the lower surface 170a of the main body portion 170. Thus, a gas flow along the lower surface 170a of the main body portion 170 can be reliably generated.

[0165] In addition, the suction port 331 is provided on the radially outer side of the suction side groove portion 431. The suction side groove portion 431 is formed such that its depth becomes shallower as it goes from the radially outer side to the radially inner side. In this way, as the distance from the suction port 331 increases, the depth of the suction side groove portion 431 becomes shallower, so that the flow velocity at a position far from the suction port 331 (here, near the radially inner side) can be increased, and thus a decrease in the suction force can be suppressed. Thus, a gas with a uniform flow velocity can flow radially on the lower surface 170a of the main body portion 170 as much as possible, and thus a negative pressure can be formed uniformly.

[0166] In addition, a plurality of suction side groove portions 431 are provided. The plurality of suction side groove portions 431 are arranged adjacent to each other on the lower surface 170a of the main body portion 170. Thus, a relatively large area for forming a negative pressure (for example, regions 501a and 502a) can be ensured.

[0167] In addition, a detection portion 350 for detecting the bonding state of the first substrate W1 and the second substrate W2 is provided between adjacent suction side groove portions 431. In this way, by arranging the plurality of suction side groove portions 431 adjacent to each other, a space for arranging the detection portion 350 can be easily ensured.

[0168] In addition, the negative pressure forming portion 320 includes a gas supply port 340 and a gas supply side groove portion 440. The gas supply port 340 is provided in the gas supply side groove portion 440, and the gas supply side groove portion 440 extends radially along the lower surface 170a of the main body portion 170. Thus, a gas flow along the lower surface 170a of the main body portion 170 can be reliably generated using the gas flowing in from the gas supply port 340.

[0169] In addition, the negative pressure forming portion 320 forms a negative pressure in the space B between the four first negative pressure regions 501 provided on the lower surface 170a of the main body portion 170 at intervals of 90 degrees and the upper surface W1n of the first substrate W1, and the negative pressure forming portion 320 forms a negative pressure in the space B between the four second negative pressure regions 502 provided on the lower surface 170a of the main body portion 170 at intervals of 45 degrees in the circumferential direction with respect to the four first negative pressure regions 501 and the upper surface W1n of the first substrate W1. In addition, the negative pressure forming portion 320 makes the negative pressure in the first negative pressure region 501 different from the negative pressure in the second negative pressure region 502. Thereby, the bonding region A (refer to Figure 7 , Figure 15 ) can be expanded in a state close to a concentric circle shape, so that the bonding accuracy between the substrates can be improved.

[0170] In addition, the first substrate W1 is a single crystal silicon wafer with a crystal orientation of

[100] on the surface. When the direction from the center of the first substrate W1 toward the [0-11] crystal orientation parallel to the surface of the first substrate W1 is defined as 0 degrees, the four first negative pressure regions 501 are provided at intervals of 90 degrees based on the 45-degree direction. Thereby, in the region (first negative pressure region 501) in the 45-degree direction where the bonding speed is the fastest, the bonding speed can be suppressed to a large extent.

[0171] In addition, the present disclosure can also adopt the following structure.

[0172] (1) A bonding device, comprising:

[0173] A first holding portion that adsorbs and holds the first substrate from above the first substrate;

[0174] A second holding portion that is disposed at a position lower than the first holding portion and adsorbs and holds the second substrate from below the second substrate; and

[0175] A plunger that presses the center portion of the first substrate to bring the center portion of the first substrate into contact with the second substrate,

[0176] wherein the first holding portion includes:

[0177] A main body portion having a lower surface facing the first substrate; and

[0178] A negative pressure forming portion for forming a negative pressure in the space between the lower surface of the main body portion separated by pressing the plunger and the upper surface of the first substrate.

[0179] (2) The bonding device according to (1), wherein

[0180] The negative pressure forming portion forms a negative pressure in the space by generating a flow of gas along the lower surface of the main body portion.

[0181] (3) The bonding device according to (1) or (2), wherein

[0182] The negative pressure forming portion forms a negative pressure in the space by generating the flow of the gas in the circumferential direction along the lower surface of the main body portion.

[0183] (4) The bonding device according to any one of (1) to (3), wherein

[0184] The negative pressure forming portion includes:

[0185] A suction port; and

[0186] A suction side groove portion, the suction port is provided in the suction side groove portion, and the suction side groove portion extends radially along the lower surface of the main body portion.

[0187] (5) The bonding device according to (4), wherein

[0188] The suction port is provided on the radially outer side of the suction side groove portion,

[0189] The suction side groove portion is formed to be shallower as it goes from the radially outer side to the radially inner side.

[0190] (6) The bonding device according to (4) or (5), wherein

[0191] A plurality of the suction side groove portions are provided,

[0192] The plurality of suction side groove portions are arranged adjacent to each other on the lower surface of the main body portion.

[0193] (7) The bonding device according to (6), wherein

[0194] A detection portion for detecting the bonding state of the first substrate and the second substrate is provided between the adjacent suction side groove portions.

[0195] (8) The bonding device according to any one of (1) to (7), wherein

[0196] The negative pressure forming portion includes:

[0197] A gas supply port; and

[0198] A gas supply side groove portion, the gas supply port is provided in the gas supply side groove portion, and the gas supply side groove portion extends radially along the lower surface of the main body portion.

[0199] (9) The bonding device according to any one of (1) to (8), wherein

[0200] The negative pressure forming portion forms a negative pressure in the space between the four first negative pressure regions provided on the lower surface of the main body portion at 90-degree intervals and the upper surface of the first substrate.

[0201] The negative pressure forming portion forms a negative pressure in the space between the four second negative pressure regions provided on the lower surface of the main body portion at a 45-degree circumferential offset relative to the four first negative pressure regions and the upper surface of the first substrate.

[0202] The negative pressure forming portion makes the negative pressure in the first negative pressure region different from the negative pressure in the second negative pressure region.

[0203] (10) The bonding device according to (9), wherein

[0204] The first substrate is a single-crystal silicon wafer with a crystal orientation of

[100] on its surface.

[0205] When the direction from the central portion of the first substrate toward the [0 - 11] crystal direction parallel to the surface of the first substrate is defined as 0 degrees, the four first negative pressure regions are provided at 90-degree intervals based on a 45-degree direction.

[0206] (11) A bonding system, comprising:

[0207] A surface modification device that modifies the surfaces of a first substrate and a second substrate;

[0208] A surface hydrophilization device that hydrophilizes the surfaces of the modified first substrate and the second substrate; and

[0209] A bonding device that bonds the hydrophilized first substrate and the second substrate using intermolecular forces,

[0210] wherein the bonding device comprises:

[0211] A first holding portion that adsorbs and holds the first substrate from above the first substrate;

[0212] A second holding portion that is disposed at a position lower than the first holding portion and adsorbs and holds the second substrate from below the second substrate; and

[0213] A plunger that presses the central portion of the first substrate to bring the central portion of the first substrate into contact with the second substrate,

[0214] The first holding portion comprises:

[0215] A main body portion having a lower surface facing the first substrate; and

[0216] A negative pressure forming portion configured to form a negative pressure in a space between the lower surface of the main body portion separated by pressing the plunger and the upper surface of the first substrate.

[0217] (12) An attaching method including the following steps;

[0218] Adsorbing and holding the first substrate from above the first substrate using a first holding portion, the first holding portion including a negative pressure forming portion and a main body portion having a lower surface facing the first substrate;

[0219] Adsorbing and holding the second substrate from below the second substrate using a second holding portion disposed at a position lower than the first holding portion;

[0220] Pressing a central portion of the first substrate using a plunger to bring the central portion of the first substrate into contact with the second substrate; and

[0221] Forming a negative pressure in a space between the lower surface of the main body portion separated by pressing the plunger and the upper surface of the first substrate using the negative pressure forming portion.

[0222] It should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. In fact, the above embodiments can be specifically implemented in various ways. Additionally, the above embodiments can be omitted, replaced, or changed in various ways without departing from the appended claims and their gist.

[0223] Explanation of reference numerals;

[0224] W1: First substrate; W2: Second substrate; 1: Bonding system; 41: Bonding device; 140: First holding portion; 141: Second holding portion; 170: Main body portion; 190: Plunger; 320: Negative pressure forming portion.

Claims

1. A bonding device, comprising: A first holding part that adsorbs and holds the first substrate from above the first substrate; A second holding part that is disposed at a position lower than the first holding part and adsorbs and holds the second substrate from below the second substrate; and A knock pin that presses the central part of the first substrate to bring the central part of the first substrate into contact with the second substrate, Among them, The first holding part includes: A main body part having a lower surface facing the first substrate; and A negative pressure forming part for forming a negative pressure in the space between the lower surface of the main body part separated by pressing the knock pin and the upper surface of the first substrate.

2. The bonding device according to claim 1, wherein The negative pressure forming part forms a negative pressure in the space by generating a gas flow along the lower surface of the main body part.

3. The bonding device according to claim 2, wherein The negative pressure forming part forms a negative pressure in the space by generating the gas flow along the circumferential direction on the lower surface of the main body part.

4. The bonding device according to claim 1, wherein The negative pressure forming part includes: A suction port; And A suction side groove part, the suction port is provided in the suction side groove part, and the suction side groove part extends radially on the lower surface of the main body part.

5. The bonding device according to claim 4, wherein The suction port is provided on the radially outer side of the suction side groove part, The suction side groove part is formed such that the depth becomes shallower as it goes from the radially outer side to the radially inner side.

6. The bonding device according to claim 4, wherein A plurality of the suction side groove parts are provided, The plurality of suction side groove parts are disposed adjacent to each other on the lower surface of the main body part.

7. The bonding device according to claim 6, wherein A detection part for detecting the bonding state of the first substrate and the second substrate is provided between the adjacent suction side groove parts.

8. The bonding device according to claim 1, wherein The negative pressure forming part includes: A gas supply port; and A gas supply side groove part, the gas supply port is provided in the gas supply side groove part, and the gas supply side groove part extends radially on the lower surface of the main body part.

9. The bonding device according to claim 1, wherein The negative pressure forming part forms a negative pressure in the space between the four first negative pressure regions provided at 90-degree intervals on the lower surface of the main body part and the upper surface of the first substrate, The negative pressure forming part forms a negative pressure in the space between the four second negative pressure regions provided on the lower surface of the main body part and offset by 45 degrees in the circumferential direction with respect to the four first negative pressure regions and the upper surface of the first substrate, The negative pressure forming part makes the negative pressure in the first negative pressure region different from the negative pressure in the second negative pressure region.

10. The bonding device according to claim 9, wherein The first substrate is a single crystal silicon wafer with a crystal orientation of [100] on the surface, When the direction from the central portion of the first substrate toward the [0-11] crystal direction parallel to the surface of the first substrate is defined as 0 degrees, the four first negative pressure regions are provided at intervals of 90 degrees with respect to the direction of 45 degrees.

11. A bonding system, comprising: A surface modification device that modifies the surfaces of a first substrate and a second substrate; A surface hydrophilicity device that makes the surfaces of the modified first substrate and the second substrate hydrophilic; And A bonding device that bonds the hydrophilic first substrate and the second substrate using intermolecular forces, wherein the bonding device includes: A first holding portion that adsorbs and holds the first substrate from above the first substrate; A second holding portion that is disposed at a position lower than the first holding portion and adsorbs and holds the second substrate from below the second substrate; and A plunger that presses the central portion of the first substrate to bring the central portion of the first substrate into contact with the second substrate, The first holding portion includes: A main body portion having a lower surface facing the first substrate; and A negative pressure forming portion that forms a negative pressure in a space between the lower surface of the main body portion separated by pressing the plunger and the upper surface of the first substrate.

12. A bonding method, including the following steps; Adsorbing and holding the first substrate from above the first substrate using a first holding portion, the first holding portion including a negative pressure forming portion and a main body portion having a lower surface facing the first substrate; Adsorbing and holding the second substrate from below the second substrate using a second holding portion disposed at a position lower than the first holding portion; Pressing the central portion of the first substrate using a plunger to bring the central portion of the first substrate into contact with the second substrate; And Forming a negative pressure in a space between the lower surface of the main body portion separated by pressing the plunger and the upper surface of the first substrate using the negative pressure forming portion.

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