Bonding device and bonding method

Abstract

A bonding device for bonding a first substrate and a second substrate, the bonding device comprising a first holding part for holding the first substrate on an upper surface by vacuum suction, a second holding part provided above the first holding part to hold the second substrate on a lower surface by vacuum suction, a pressing member provided on the second holding part to press the center portion of the second substrate, a plurality of first detection parts provided on the second holding part to detect detachment of the second substrate from the second holding part, and a plurality of second detection parts, wherein: the first detection parts include a displacement sensor capable of detecting the distance between the second holding part and the second substrate when the second substrate is detached from the second holding part at least at a position corresponding to the first detection parts; and the second detection parts include a fiber sensor capable of detecting whether or not the second substrate is detached from the second holding part at least at a position corresponding to the second detection parts.

Description

Bonding device and bonding method

[0001] The present disclosure relates to a joining device and a joining method.

[0002] Patent document 1 discloses a bonding device for bonding substrates together, in which a substrate detection unit detects a bonding wave when a first substrate held by a first holding unit is released from the first holding unit.

[0003] Japanese Patent Application Publication No. 2021-005724

[0004] The technology according to the present disclosure inspects the state of the bonding process of the substrates and performs the bonding process appropriately.

[0005] One aspect of the present disclosure is a bonding device for bonding a first substrate and a second substrate, comprising: a first holding section that suction-holds the first substrate to an upper surface by vacuuming; a second holding section that is provided above the first holding section and suction-holds the second substrate to a lower surface by vacuuming; a pressing member that is provided on the second holding section and presses the center of the second substrate; a plurality of first detection sections and a plurality of second detection sections that are provided on the second holding section and detect detachment of the second substrate from the second holding section; wherein the first detection sections comprise displacement sensors that are capable of detecting the distance between the second holding section and the second substrate when the second substrate detaches from the second holding section at least at a position corresponding to the first detection sections; and the second detection sections comprise fiber sensors that are capable of detecting whether the second substrate has detached from the second holding section at least at a position corresponding to the second detection sections.

[0006] According to the present disclosure, the state of the bonding process of the substrates can be inspected and the bonding process can be performed appropriately.

[0007] FIG. 1 is a plan view showing an outline of an exemplary configuration of a bonding system. FIG. 2 is a side view showing an outline of an exemplary internal configuration of the bonding system. FIG. 3 is a side view showing an outline of an exemplary configuration of a second substrate and a first substrate. FIG. 4 is a cross-sectional view showing an outline of an exemplary configuration of a bonding device. FIG. 5 is a longitudinal sectional view showing an outline of an exemplary configuration of a bonding device. FIG. 6 is a longitudinal sectional view showing an outline of an exemplary configuration of an upper chuck, an upper chuck holding unit, and a lower chuck. FIG. 7 is a plan view of the upper chuck as viewed from below. FIG. 8 is an explanatory diagram showing an outline of an exemplary configuration of a suction unit, a suction tube, and a vacuum pump. FIG. 9 is a flowchart showing main steps of a bonding process. FIG. 10 is an explanatory diagram showing an example of a state in the bonding process. FIG. 11 is an explanatory diagram showing an example of a state in the bonding process. FIG. 12 is an explanatory diagram showing an example of a state in the bonding process.

[0008] In recent years, semiconductor devices have become increasingly highly integrated. When multiple highly integrated semiconductor devices are arranged horizontally and connected with wiring to produce a product, the wiring length increases, which raises concerns about increased wiring resistance and wiring delay.

[0009] Therefore, the use of three-dimensional integration technology for stacking semiconductor devices in three dimensions has been proposed. In this three-dimensional integration technology, two semiconductor substrates (hereinafter referred to as "substrates") are bonded using a bonding system, such as that described in Patent Document 1. For example, the bonding system includes a surface modification device that modifies the surfaces of the substrates to be bonded, a surface hydrophilization device that hydrophilizes the surfaces of the substrates modified by the surface modification device, and a bonding device that bonds the substrates whose surfaces have been hydrophilized by the surface hydrophilization device. In this bonding system, the surface modification device performs plasma treatment on the surfaces of the substrates to modify the surfaces, and the surface hydrophilization device further supplies pure water to the surfaces of the substrates to hydrophilize them. The substrates are then bonded to each other in the bonding device using van der Waals forces and hydrogen bonds (intermolecular forces).

[0010] The bonding device includes a lower chuck that holds one substrate (hereinafter referred to as the "first substrate") on its upper surface, an upper chuck that is disposed above the lower chuck and holds another substrate (hereinafter referred to as the "second substrate") on its lower surface, and a pressing member that is disposed on the upper chuck and presses the center of the second substrate. In this bonding device, the second substrate held by the upper chuck and the first substrate held by the lower chuck are positioned opposite each other, and the pressing member presses the centers of the second substrate and the first substrate to bring them into contact, bonding the centers together to form a bonding region. A so-called bonding wave then occurs, in which the bonding region expands (propagates) from the center of the substrate toward the periphery. The second substrate and the first substrate are then bonded together.

[0011] To suppress distortion of the bonded laminated substrates, it is preferable for the bonding wave to expand evenly, i.e., concentrically, from the center to the periphery of the substrates. The bonding apparatus described in the aforementioned Patent Document 1 discloses a substrate detection unit that monitors the bonding wave. In this regard, in order to monitor the propagation behavior of the bonding wave in more detail, it is desirable to provide substrate detection units at more points on the upper chuck. However, since the upper chuck is provided with various components other than the substrate detection unit, providing more substrate detection units may reduce the design freedom of the other components. In other words, considering the other components, it is difficult to provide more substrate detection units. Therefore, there is room for improvement in conventional substrate bonding processes.

[0012] Therefore, the technology disclosed herein inspects the state of the bonding process of the substrates and performs the bonding process appropriately. The configuration of the bonding system according to this embodiment will be described below with reference to the drawings. Note that, in this specification, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0013] <Configuration of Bonding System> First, the configuration of the bonding system according to this embodiment will be described. Fig. 1 is a plan view showing an outline of the configuration of the bonding system 1. Fig. 2 is a side view showing an outline of the internal configuration of the bonding system 1. In the following, to clarify the positional relationships, mutually orthogonal X-axis, Y-axis, and Z-axis directions are defined, and the positive Z-axis direction is defined as the vertically upward direction.

[0014] 3, the bonding system 1 bonds, for example, two substrates, a first substrate W and a second substrate S, to obtain a laminated substrate T. In the following description, the first substrate W and the second substrate S may be collectively referred to simply as "substrates." In the first substrate W, the surface bonded to the second substrate S is referred to as the front surface Wa, and the surface opposite the front surface Wa is referred to as the back surface Wb. Similarly, in the second substrate S, the surface bonded to the first substrate W is referred to as the front surface Sa, and the surface opposite the front surface Sa is referred to as the back surface Sb.

[0015] The first substrate W is a semiconductor substrate such as a silicon wafer, and has a device layer D including a plurality of circuits and the like formed on its surface Wa. The second substrate S is a substrate that supports the first substrate W. The second substrate S is made of a material that transmits visible light of a desired wavelength, such as a silicon wafer.

[0016] The combination of two substrates bonded by the bonding system 1 is not limited to the above, and any desired combination of substrates can be bonded. In one embodiment, the first substrate W and the second substrate W are both device wafers. In another embodiment, the first substrate W is a device wafer, and the second substrate W is an epitaxial wafer.

[0017] In the following description, it is assumed that the first substrate W is disposed on the lower side and the second substrate S is disposed on the upper side, but this arrangement is for the convenience of explanation and is not limiting.

[0018] As shown in FIG. 1, the bonding system 1 includes a FOUP F that can accommodate a plurality of substrates W and S and a plurality of laminated substrates T, for example, between the outside and the substrates W and S. Ｗ , F Ｓ , F ＴThe apparatus has a configuration in which a loading / unloading station 2 through which the substrates W, S and the laminated substrate T are loaded and unloaded is integrally connected, and a processing station 3 equipped with various processing devices that perform desired processing on the substrates W, S and the laminated substrate T. In one embodiment, an inspection station 4 is provided adjacent to the processing station 3.

[0019] The loading / unloading station 2 is provided with a FOUP placement table 10. The FOUP placement table 10 is provided with a plurality of, for example, four FOUP placement plates 11. The FOUP placement plates 11 are arranged in a row in the horizontal Y-axis direction (the up-down direction in FIG. 1 ). These FOUP placement plates 11 are used to mount the FOUPs F to the outside of the joining system 1. Ｗ , F Ｓ , F Ｔ When carrying in and out, Ｗ , F Ｓ , F Ｔ In this way, the loading / unloading station 2 is configured to be able to hold a plurality of first substrates W, a plurality of second substrates S, and a plurality of superimposed substrates T. The number of FOUP placement plates 11 is not limited to that in this embodiment, and can be set arbitrarily. One of the FOUPs may also be used for recovering abnormal substrates. In other words, this FOUP is capable of separating a substrate in which an abnormality has occurred in the bonding between the second substrate S and the first substrate W due to various factors from the other normal superimposed substrates T. In this embodiment, the plurality of FOUPs F Ｔ Of these, one hoop F Ｔ is used to recover abnormal substrates, and other FOUP F Ｔ is used to accommodate a normal laminated substrate T.

[0020] The carry-in / out station 2 is provided with a substrate transport section 20 adjacent to the FOUP mounting table 10. The substrate transport section 20 is provided with a substrate transport device 22 that is movable on a transport path 21 extending in the Y-axis direction. The substrate transport device 22 is also movable in the vertical direction and around the vertical axis (Z-axis) (in the θ direction). The substrate transport device 22 also transports the FOUP F on each FOUP mounting plate 11. Ｗ , F Ｓ , F Ｔand the transition devices 50 and 51 in the third processing block G3 of the processing station 3, which will be described later, can transport the substrates W, S and the laminated substrate T between them.

[0021] Processing station 3 is provided with multiple processing blocks, e.g., three processing blocks G1, G2, and G3, each equipped with various devices. For example, a first processing block G1 is provided on the front side (negative Y-axis side in FIG. 1 ) of processing station 3, and a second processing block G2 is provided on the rear side (positive Y-axis side in FIG. 1 ) of processing station 3. Furthermore, a third processing block G3 is provided on the loading / unloading station 2 side of processing station 3 (negative X-axis side in FIG. 1 ).

[0022] The first processing block G1 is provided with a surface modification device 30 that modifies, for example, surfaces Wa, Sa of substrates W, S. In the surface modification device 30, a processing gas, such as oxygen gas or nitrogen gas, is excited to form plasma and ionized in a reduced pressure atmosphere. The oxygen ions or nitrogen ions are irradiated onto the surfaces Wa, Sa, so that the surfaces Wa, Sa are plasma-processed and modified.

[0023] In the second processing block G2, a surface hydrophilization device 40 that hydrophilizes the surfaces Wa, Sa of the substrates W, S using, for example, pure water and cleans the surfaces Wa, Sa, and a bonding device 41 that bonds the substrates W, S are arranged in this order in the horizontal X-axis direction from the loading / unloading station 2. The configuration of the bonding device 41 will be described later.

[0024] In the surface hydrophilization device 40, pure water is supplied onto the substrates W, S while the substrates W, S are rotated, for example, while being held by a spin chuck. The supplied pure water then spreads over the surfaces Wa, Sa of the substrates W, S, thereby making the surfaces Wa, Sa hydrophilic.

[0025] In the third processing block G3, transition devices 50 and 51 for the substrates W and S and the laminated substrate T are provided in two stages in this order from the bottom, as shown in FIG.

[0026] As shown in FIG. 1 , a substrate transfer region 60 is formed in an area surrounded by the first processing block G1 to the third processing block G3. A substrate transfer device 61, for example, is disposed in the substrate transfer region 60. The substrate transfer device 61 has a transfer arm that is movable, for example, vertically, horizontally (X-axis direction, Y-axis direction), and around a vertical axis (Z-axis). The substrate transfer device 61 moves within the substrate transfer region 60 and can transfer substrates W, S, and superimposed substrates T to desired devices in the surrounding first processing block G1, second processing block G2, and third processing block G3. The substrate transfer device 61 can also transport substrates W, S, and superimposed substrates T to the inspection station 4.

[0027] The above-described joint system 1 is provided with at least one control unit 70 as shown in FIG. 1 . The control unit 70 processes computer-executable instructions that cause the joint system 1 to perform the various steps described in this disclosure. The control unit 70 may be configured to control each element of the joint system 1 to perform the various steps described herein. In one embodiment, part or all of the control unit 70 may be included in the joint system 1. The control unit 70 may include a processing unit, a storage unit, and a communication interface. The control unit 70 is realized, for example, by a computer. The processing unit may be configured to read from the storage unit a program that provides logic or routines that enable various control operations to be performed, and to execute the read program to perform various control operations. This program may be stored in the storage unit in advance, or may be acquired via a medium when needed. The acquired program is stored in the storage unit and read from the storage unit by the processing unit for execution. The medium may be various computer-readable storage media, or may be a communication line connected to the communication interface. The storage medium may be temporary or non-temporary. The processing unit may be a CPU (Central Processing Unit) or one or more circuits. The storage unit may include a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the bonding system 1 via a communication line such as a LAN (Local Area Network).

[0028] <Configuration of Bonding Apparatus> (Overall Configuration of Bonding Apparatus) Next, a description will be given of the configuration of the above-mentioned bonding apparatus 41. The bonding apparatus 41 has a processing vessel 100 whose interior can be sealed, as shown in Figures 4 and 5. A loading / unloading port 101 for the substrates W, S and the laminated substrate T is formed on the side of the processing vessel 100 on the side facing the substrate transfer region 60, and the loading / unloading port 101 is provided with an opening / closing shutter 102.

[0029] The interior of the processing vessel 100 is divided into a transfer region R1 and a processing region R2 by an inner wall 103. The above-mentioned loading / unloading port 101 is formed on a side surface of the processing vessel 100 in the transfer region R1. In addition, loading / unloading ports 104 for the substrates W, S, and the laminated substrate T are also formed in the inner wall 103.

[0030] On the positive Y-axis side of the transfer region R1, there is provided a transition 110 for temporarily placing the substrates W, S, and the superimposed substrate T. The transition 110 is formed, for example, in two stages, and any two of the substrates W, S, and the superimposed substrate T can be placed thereon at the same time.

[0031] The transfer region R1 is provided with a substrate transfer mechanism 111. The substrate transfer mechanism 111 has a transfer arm that is movable, for example, vertically, horizontally (in the X-axis direction and the Y-axis direction) and around a vertical axis (the Z-axis). The substrate transfer mechanism 111 can transfer substrates W, S, and laminated substrates T within the transfer region R1 or between the transfer region R1 and the processing region R2.

[0032] A position adjustment mechanism 120 that adjusts the horizontal orientation of the substrates W, S is provided on the negative Y-axis side of the transfer region R1. The position adjustment mechanism 120 has a base 121 equipped with a holder (not shown) that holds and rotates the substrates W, S, and a detector 122 that detects the position of the notch portion of the substrates W, S. The position adjustment mechanism 120 rotates the substrates W, S held on the base 121 while detecting the position of the notch portion of the substrates W, S with the detector 122, thereby adjusting the position of the notch portion and adjusting the horizontal orientation of the substrates W, S. The structure that holds the substrates W, S on the base 121 is not particularly limited, and various structures such as a pin chuck structure or a spin chuck structure may be used.

[0033] The transport region R1 is also provided with an inversion mechanism 130 that inverts the front and back surfaces of the second substrate S. The inversion mechanism 130 has a holding arm 131 that holds the second substrate S. The holding arm 131 extends in the horizontal direction (X-axis direction). The holding arm 131 is also provided with holding members 132 that hold the second substrate S at, for example, four locations.

[0034] The holding arm 131 is supported by a drive unit 133 equipped with, for example, a motor. This drive unit 133 allows the holding arm 131 to rotate around a horizontal axis. The holding arm 131 is also rotatable around the drive unit 133 and movable horizontally (in the X-axis direction). Another drive unit (not shown), equipped with, for example, a motor, is provided below the drive unit 133. This other drive unit allows the drive unit 133 to move vertically along a support column 134 extending vertically. In this way, the drive unit 133 allows the second substrate S held by the holding member 132 to rotate around the horizontal axis and move vertically and horizontally. The second substrate S held by the holding member 132 can also rotate around the drive unit 133 and move between the position adjustment mechanism 120 and an upper chuck 141 (described later).

[0035] The processing region R2 is provided with a lower chuck 140 as a first holding part that places and suction-holds the first substrate W on its upper surface, and an upper chuck 141 as a second holding part that suction-holds the second substrate S on its lower surface. The lower chuck 140 is provided below the upper chuck 141 and is configured to be able to be arranged opposite the upper chuck 141. In other words, the first substrate W held by the lower chuck 140 and the second substrate S held by the upper chuck 141 can be arranged opposite each other.

[0036] The upper chuck 141 is supported by an upper chuck stage 150 provided above the upper chuck 141. The upper chuck stage 150 is provided with an upper imaging unit 151 that captures an image of the front surface Wa of the first substrate W held by the lower chuck 140. That is, the upper imaging unit 151 is provided adjacent to the upper chuck 141. The upper imaging unit 151 may be, for example, a CCD camera.

[0037] The upper chuck stage 150 is supported by a rotating unit 153 serving as a moving mechanism, which is provided on the ceiling surface of the processing vessel 100 via a plurality of support members above the upper chuck stage 150. The rotating unit 153 is configured to rotate the upper chuck stage 150 and the upper chuck 141 around a vertical axis (Z-axis). The rotating unit 153 includes, for example, a servo driver (not shown) and a servo motor (not shown).

[0038] The rotating unit 153 is provided with a linear scale 154 as a measuring unit. The linear scale 154 measures the θ azimuth angle (position in the Z-axis rotation direction) of the upper chuck 141. Note that although the linear scale 154 measures the θ azimuth angle of the rotating unit 153, the rotating unit 153, the support member 152, the upper chuck stage 150, and the upper chuck 141 are rigid bodies, and the linear scale 154 essentially measures the θ azimuth angle of the upper chuck 141.

[0039] The configuration for rotating the upper chuck 141 and the configuration for measuring the θ azimuth angle of the upper chuck 141 are not limited to this embodiment, and can be designed arbitrarily.

[0040] The lower chuck 140 is supported by a lower chuck stage 160 provided below the lower chuck 140. The lower chuck stage 160 is provided with a lower imaging unit 161 that captures an image of the surface Sa of the second substrate S held by the upper chuck 141. That is, the lower imaging unit 161 is provided adjacent to the lower chuck 140. The lower imaging unit 161 may be, for example, a CCD camera.

[0041] The lower chuck stage 160 is supported by a first lower chuck moving unit 164 serving as a moving mechanism provided below the lower chuck stage 160. As will be described later, the first lower chuck moving unit 164 is configured to move the lower chuck 140 in the horizontal direction (X-axis direction). The first lower chuck moving unit 164 is also configured to move the lower chuck 140 in the vertical direction (Z-axis direction). The first lower chuck moving unit 164 incorporates, for example, a servo driver (not shown) and a servo motor (not shown). In the present embodiment, the first lower chuck moving unit 164 moves the lower chuck 140 in the X-axis direction and the Z-axis direction. However, separate moving units may be provided to move the lower chuck 140 in the X-axis direction and the Z-axis direction.

[0042] The first lower chuck moving part 164 is provided on the lower surface side of the first lower chuck moving part 164 and is attached to a pair of rails 165, 165 extending in the horizontal direction (X-axis direction). The first lower chuck moving part 164 is configured to be movable along the rails 165.

[0043] The pair of rails 165, 165 are disposed on a second lower chuck moving part 166 serving as a moving mechanism. The second lower chuck moving part 166 is provided on the underside of the second lower chuck moving part 166 and is attached to a pair of rails 167, 167 extending in the horizontal direction (Y-axis direction). The second lower chuck moving part 166 is configured to be movable along the rails 167, i.e., configured to move the lower chuck 140 in the horizontal direction (Y-axis direction). The second lower chuck moving part 166 incorporates, for example, a servo driver and a servo motor. The pair of rails 167, 167 are disposed on a mounting table 168 provided on the bottom surface of the processing vessel 100.

[0044] The configuration for moving the lower chuck 140 in the X-axis direction, the Y-axis direction, and the Z-axis direction, and the configuration for measuring the X-axis position, the Y-axis position, and the Z-axis position of the lower chuck 140 are not limited to this embodiment, and can be designed as desired.

[0045] (Configuration of Upper Chuck and Lower Chuck) Next, the detailed configuration of the lower chuck 140 and the upper chuck 141 of the bonding device 41 will be described. The upper chuck 141 employs a pin chuck system as shown in FIG. 6. The upper chuck 141 has a main body 170 having a diameter equal to or greater than the diameter of the second substrate S in a plan view. A plurality of pins 171 that come into contact with the back surface Sb of the second substrate S are provided on the lower surface of the main body 170. Note that the pins 171 are not shown in FIG. 7.

[0046] A through-hole 172 is formed in the center of the main body 170, penetrating the main body 170 in the thickness direction. The center of this main body 170 corresponds to the center of the second substrate S that is held by suction on the upper chuck 141. The through-hole 172 is adapted to receive a tip end (striker 193) of an actuator 191 serving as a pushing member in a pushing unit 190, which will be described later.

[0047] Furthermore, first to fifth suction units 181 to 185 are provided on the underside of the main body unit 170 as a plurality of suction units that vacuum-suck and adsorb the second substrate S. The first to fifth suction units 181 to 185 each have the same height as the pin 171, and come into contact with the back surface Sb of the second substrate S. Note that Fig. 6 is a cross-sectional view passing through the first suction unit 181 and the third suction unit 183, and only these are shown.

[0048] As shown in FIG. 7, the first suction portion 181, the second suction portion 182, the third suction portion 183, and the fourth suction portion 184 each have an arc shape in a plan view.

[0049] The first suction portions 181 and the second suction portions 182 are arranged at predetermined intervals in a circumferential direction on the outer periphery of the main body portion 170 on a circle concentric with the main body portion 170. A desired number of first suction portions 181 are provided in each of the 90° directions described below in Fig. 7 (five in each direction in this embodiment, a total of 20 first suction portions 181). A desired number of second suction portions 182 are provided in each of the 45° directions described below in Fig. 7 (five in each direction in this embodiment, a total of 20 second suction portions 182).

[0050] The third suction portions 183 and the fourth suction portions 184 are arranged in a circumferential direction at predetermined intervals on a circle concentric with the main body portion 170, inside the first suction portion 181 and the second suction portion 182 and outside the fifth suction portion 185. A desired number of third suction portions 183 are provided in each of the 90° directions described below in Fig. 7 (five in each direction in this embodiment, a total of 20). Also, a desired number of fourth suction portions 184 are provided in each of the 45° directions described below in Fig. 7 (five in each direction in this embodiment, a total of 20).

[0051] The fifth suction portion 185 has a circular ring shape in a plan view. A plurality of fifth suction portions 185 (for example, three fifth suction portions 185) are arranged radially at predetermined intervals on a circumference concentric with the main body portion 170, closer to the inner periphery of the main body portion 170 than the first to fourth suction portions 181 to 184. The centers of the first to fourth suction portions 181 to 184 and the center of the fifth suction portion 185 are arranged on the center line of the main body portion 170.

[0052] 8, first to fifth vacuum pumps 181b to 185b are connected to the first to fifth suction units 181 to 185 via first to fifth suction pipes 181a to 185a, respectively. The first to fifth suction pipes 181a to 185a each include a branching section to which the first to fifth suction units 181 to 185 are connected, and a junction section where the branching sections join together and are connected to the first to fifth vacuum pumps 181b to 185b. By drawing a vacuum using the first to fifth vacuum pumps 181b to 185b, the first to fifth suction units 181 to 185 can individually suck the second substrate S.

[0053] 6, a pressing unit 190 that presses the center of the second substrate S is provided on the upper surface of the upper chuck stage 150. The pressing unit 190 has an actuator unit 191 and a cylinder unit 192 as contact members. Note that the pressing unit 190 is not shown in FIG.

[0054] The actuator unit 191 generates a constant pressure in a fixed direction using air supplied from an electropneumatic regulator (not shown), and can generate the pressure at a constant level regardless of the position of the point of application of the pressure. The air from the electropneumatic regulator allows the actuator unit 191 to abut against the center of the second substrate S and control the pressing load applied to the center of the second substrate S. A striker 193 serving as a pressing member provided at the tip of the actuator unit 191 is inserted through the through-hole 172 and can be raised and lowered vertically by the air from the electropneumatic regulator.

[0055] The actuator part 191 is supported by a cylinder part 192. The cylinder part 192 can move the actuator part 191 in the vertical direction by means of a drive part (not shown) having a built-in motor, for example.

[0056] As described above, the pushing unit 190 controls the pressing load by the actuator unit 191, and controls the movement of the actuator unit 191 by the cylinder unit 192. Then, when bonding the substrates W and S, which will be described later, the pushing unit 190 can bring the center of the second substrate S into contact with the center of the first substrate W and press them together.

[0057] The lower chuck 140 employs a pin chuck system similar to the upper chuck 141. The lower chuck 140 has a main body 200 having a diameter equal to or larger than the diameter of the first substrate W in a plan view. A plurality of pins 201 that come into contact with the back surface Sb of the first substrate W are provided on the upper surface of the main body 200. In addition, an outer rib 202 that has the same height as the pins 201 and supports the outer periphery of the back surface Sb of the first substrate W is provided on the outer periphery of the upper surface of the main body 200. The outer rib 202 is provided in a ring shape around the outside of the plurality of pins 201.

[0058] Furthermore, an inner rib 203 is provided on the upper surface of the main body 200, inside the outer rib 202, and has the same height as the pins 201. The inner rib 203 supports the back surface Sb of the first substrate W. The inner rib 203 is provided in a ring shape concentric with the outer rib 202. An inner region 204 of the outer rib 202 (hereinafter sometimes referred to as the suction region 204) is partitioned into a first suction region 204a inside the inner rib 203 and a second suction region 204b outside the inner rib 203.

[0059] A first suction port 205a for evacuating the first substrate W in the first suction region 204a is formed on the upper surface of the main body 200. The first suction port 205a is formed, for example, at one location in the first suction region 204a. A first suction pipe 206a provided inside the main body 200 is connected to the first suction port 205a. Furthermore, a first vacuum pump 207a is connected to the first suction pipe 206a.

[0060] Further, second suction ports 205b for evacuating the first substrate W in the second suction region 204b are formed on the upper surface of the main body 200. The second suction ports 205b are formed, for example, at two locations in the second suction region 204b. A second suction pipe 206b provided inside the main body 200 is connected to the second suction ports 205b. Furthermore, a second vacuum pump 207b is connected to the second suction pipe 206b.

[0061] Then, suction regions 204a, 204b formed by being surrounded by the first substrate W, the main body 200, and the outer rib 202 are evacuated through suction ports 205a, 205b, respectively, to reduce the pressure in the suction regions 204a, 204b. At this time, because the atmosphere outside the suction regions 204a, 204b is atmospheric pressure, the first substrate W is pressed toward the suction regions 204a, 204b by the atmospheric pressure in proportion to the reduced pressure, and the first substrate W is sucked and held by the lower chuck 140. The lower chuck 140 is configured to be able to evacuate the first substrate W from each of the first suction region 204a and the second suction region 204b.

[0062] In the lower chuck 140, through holes (not shown) that penetrate the main body 200 in the thickness direction are formed in, for example, three locations near the center of the main body 200. Elevating pins provided below the first lower chuck moving part 164 are adapted to be inserted into the through holes.

[0063] Guide members (not shown) are provided on the outer periphery of the main body 200 to prevent the substrates W, S, and the laminated substrate T from jumping out of or sliding off the lower chuck 140. The guide members are provided at multiple locations, for example, four locations, at equal intervals on the outer periphery of the main body 200. The operation of each part of the bonding device 41 is controlled by the control unit 70 described above.

[0064] (First Detector and Second Detector) As will be described later, when bonding the second substrate S and the first substrate W, first, the pressing unit 190 presses down the center of the second substrate S. Then, the center of the second substrate S is brought into contact with the center of the first substrate W, and the centers of the second substrate S and the first substrate W are bonded together by intermolecular forces, thereby forming a bonded region in the centers of both substrates. After that, a bonding wave is generated that propagates from the centers of both substrates W, S toward their outer peripheries, bonding the entire surfaces Sa, Wa of the second substrate S and the first substrate W together.

[0065] The main body 170 is provided with a first detector and a second detector to detect the bonding wave.

[0066] Specifically, the main body 170 is provided with a displacement sensor 210 as a first detection unit that detects detachment of the second substrate S from the main body 170. As shown in Fig. 7, the displacement sensors 210 are arranged on the outer periphery of the main body 170 between the first and second suction units 181, 182 and the third and fourth suction units 183, 184, with multiple (e.g., eight) displacement sensors 210 arranged circumferentially at 45° intervals on a circle concentric with the main body 170. Furthermore, one displacement sensor 210 is arranged near the center of the main body 170, for example, near the through-hole 172. In the following description, the displacement sensor 210 arranged between the first and second suction units 181, 182 and the third and fourth suction units 183, 184 may be referred to as an outer periphery displacement sensor 210e, and the displacement sensor 210 arranged in the center of the main body 170 may be referred to as a central displacement sensor 210c.

[0067] The displacement sensor 210 may be, for example, a capacitance sensor or a distance measurement sensor. When a capacitance sensor is used, the distance between the upper chuck 141 and the second substrate S can be measured by measuring the capacitance with the second substrate S. When a distance measurement sensor is used, the displacement sensor 210 emits laser light toward the second substrate S and receives the reflected light, thereby measuring the distance between the upper chuck 141 and the second substrate S. By measuring the distance between the upper chuck 141 and the second substrate S in this manner, the sensor 175 can detect the contact state between the second substrate S and the first substrate W (in other words, the release state of the second substrate S from the upper chuck 141). This makes it possible to grasp the bonding wave.

[0068] In one embodiment, the lower chuck 140 is configured such that the central and peripheral portions have different heights, with the peripheral portion being lower than the central portion. In other words, the lower chuck 140 according to one embodiment is configured such that the peripheral portion is farther from the upper chuck 141 than the central portion. Even in this case, the central displacement sensor 210c and the peripheral displacement sensor 210e are provided, so that the movement distances of the second substrate S at the central and peripheral portions, which are at different heights, can be detected, and the bonding wave can be grasped.

[0069] Alternatively, the displacement sensor 210 may be, for example, a fluid sensor. In this case, a suction pad (not shown) is provided on the main body 170, i.e., at the position indicated by the reference numeral "210" in FIGS. 6 and 7 , and the displacement sensor 210 is provided on a suction tube (not shown) connected to the suction pad. Note that the suction pad is not intended to suction and hold the second substrate S; rather, it evacuates the second substrate S at a minute pressure, e.g., approximately -10 kPa, that does not affect the bonding wave. The displacement sensor 210 measures the flow rate or pressure of the gas flowing through each suction tube. For example, when the second substrate S is released from the upper chuck 141, the flow of gas in the suction tube changes, resulting in changes in the flow rate and pressure of the gas. The displacement sensor 210 measures the change in the air flow in the suction tube and can detect the release of the second substrate S from the upper chuck 141 (in other words, the contact state between the second substrate S and the first substrate W). Furthermore, the distance between the upper chuck 141 and the second substrate S can be determined from the flow rate or pressure value. In this case, the relationship between the flow rate or pressure value of the gas flowing through the suction pipe and the distance between the upper chuck 141 and the second substrate S may be obtained in advance. This allows the bonding wave to be grasped. Note that the displacement sensor 210 may be provided for each of the first to fifth suction pipes 181a to 185a. In one embodiment, the reference numeral "210" shown in FIGS. 6 and 7 is an air jetting unit instead of the suction pad. An air supply pipe is connected to the air jetting unit, and a fluid sensor serving as the displacement sensor 210 is provided in the air supply pipe. The air jetting unit is configured to jet air toward the second substrate S with a very small pressure that does not affect the bonding wave. As in the above case, the displacement sensor 210 measures the flow rate or pressure of the air flowing through each air supply pipe. The distance between the upper chuck 141 and the second substrate S can be determined from the flow rate or pressure value.

[0070] In one embodiment, the central displacement sensor 210c is included in the pushing unit 190. In this case, as an example, the pushing unit 190 includes a measurement unit (not shown) that can measure the movement distance of the striker 193 in the actuator unit 191. The measurement result of the movement distance of the striker 193 by the measurement unit is output to the control unit 70. The control unit 70 determines the output movement distance of the striker 193 as the distance between the main body unit 170 and the second substrate S. Therefore, the measurement unit in the pushing unit 190 functions as the central displacement sensor 210c according to one embodiment.

[0071] The main body 170 is also provided with a fiber sensor 220 serving as a second detection unit that detects detachment of the second substrate S from the main body 170. In this embodiment, the fiber sensor 220 includes an outer peripheral fiber sensor 220e, an intermediate fiber sensor 220m, and an inner peripheral fiber sensor 220c. As shown in FIG. 7 , a plurality of outer peripheral fiber sensors 220e (e.g., eight) are arranged circumferentially at 45° intervals on a circle concentric with the main body 170 between the first and second suction units 181, 182 and the third and fourth suction units 183, 184. The outer peripheral fiber sensors 220e and the outer peripheral displacement sensors 210e are arranged alternately in the circumferential direction. The intermediate fiber sensors 220m and the inner peripheral fiber sensors 220c are arranged circumferentially at predetermined intervals on a circle concentric with the main body 170 between the plurality of fifth suction units 185. A plurality of intermediate fiber sensors 220m, for example, 16, are arranged circumferentially at intervals of 22.5° between the outermost fifth suction section 185 and the intermediate fifth suction section 185. A plurality of inner fiber sensors 220c, for example, eight, are arranged circumferentially at intervals of 45° between the intermediate fifth suction section 185 and the innermost fifth suction section 185. Furthermore, a plurality of intermediate fiber sensors 220m and inner fiber sensors 220c are provided on the outer periphery side of the central displacement sensor 210c and on the central side of the outer periphery displacement sensor 210e. The intermediate fiber sensors 220m and inner fiber sensors 220c according to this embodiment are further arranged radially at a predetermined interval on the center line of the main body 170 between the central displacement sensor 210c and the outer periphery displacement sensor 210e.

[0072] A reflective fiber sensor is used as the fiber sensor 220. The fiber sensor 220 emits light toward the second substrate S and receives the reflected light to measure the amount of received light. By measuring the amount of received reflected light, the orthogonality between the optical axis and the second substrate S can be determined. That is, when the amount of reflected light is small, the orthogonality between the optical axis and the second substrate S is large (the tilt of the second substrate S is large), meaning that the second substrate S is separated from the upper chuck 141 but is not in contact with the first substrate W. On the other hand, when the amount of reflected light is large, the orthogonality between the optical axis and the second substrate S is small (the tilt of the second substrate S is small), meaning that the second substrate S is separated from the upper chuck 141 and is in contact with the first substrate W. Therefore, by measuring the amount of reflected light with the fiber sensor 220, it is possible to detect the contact state between the second substrate S and the first substrate W at the position of the fiber sensor 220 (in other words, the detached state of the second substrate S from the upper chuck 141), thereby making it possible to grasp the bonding wave.

[0073] Furthermore, a reflective fiber sensor as the fiber sensor 220 generally occupies a smaller portion of the main body 170 than a capacitance sensor or distance measurement sensor as the displacement sensor 210. Therefore, the design freedom of other components in the upper chuck 141 can be improved compared to when the same number of displacement sensors 210 are provided. In other words, by using the fiber sensors 220, it is possible to arrange detection units at more points than when all detection units are configured with displacement sensors 210. This makes it possible to grasp the propagation behavior of the bonding wave in more detail.

[0074] In one embodiment, a sensor that emits white light (referred to herein as a "white fiber sensor") is used as the fiber sensor 220. After extensive studies, the inventors have found that using a white fiber sensor has the following advantages.

[0075] The detection sensitivity of white light is less affected by the type of film that may be formed on the surface of the second substrate S. Specifically, for example, conventional fiber sensors use red light from the perspective of luminous efficiency, but it has been found that certain film types have high absorbance of red light and low reflectance of red light for those film types. In contrast, by using a white fiber sensor as the fiber sensor 220, a desired reflectance can be ensured regardless of the type of film on the second substrate S, and a desired detection sensitivity can be obtained.

[0076] Furthermore, when white light is used, it has been found that when the second substrate S is separated from the upper chuck 141 and moved a certain distance, the difference in the amount of light received by the fiber sensor 220 before and after the movement is sufficiently larger than the variation in the difference in light amount per unit movement amount. Therefore, it has been found that the white fiber sensor has sufficient detection sensitivity to detect the separation of the second substrate S, even when the influence of the variation in the difference in light amount is taken into consideration.

[0077] The displacement sensor 210 and the fiber sensor 220 are arranged on the center line (dotted line in Figure 7) passing through the center of the main body 170 so as to be rotationally symmetric, for example, 45 degrees rotationally symmetric, about the center of the main body 170.

[0078] Here, the second substrate S is, for example, a single-crystal silicon substrate whose crystal orientation in a direction perpendicular to the surface Sa is

[100] . The second substrate S is adsorbed to the upper chuck 141 using a notch formed on the outer edge of the second substrate S in the

[011] crystal orientation as a reference. The bonding wave propagates faster in the 45°, 135°, 225°, and 315° directions (sometimes referred to as "45° directions" in this specification) shown in FIG. 7 , which are based on the direction from the center of the second substrate S toward the

[010] crystal orientation parallel to the surface Sa of the second substrate S, compared to the 0°, 90°, 180°, and 270° directions (sometimes referred to as "90° directions" in this specification) shown in FIG. 7 , which are based on the direction from the center of the second substrate S toward the

[010] crystal orientation parallel to the surface Sa of the second substrate S. As a result, when suction at each suction section is stopped simultaneously, the shape of the bonding wave, which was circular at the start of bonding (center bonding), approaches a rectangle with vertices at 45° angles as it propagates.

[0079] In this embodiment, eight displacement sensors 210 are provided concentrically with the main body 170, i.e., provided in both the 90° and 45° directions. Therefore, by using these displacement sensors 210 to detect the separation of the second substrate S from the upper chuck 141, it is possible to grasp the behavior of the bonding wave that propagates at different speeds in the 90° and 45° directions.

[0080] Furthermore, by providing the fiber sensor 220, the propagation behavior of the bonding wave can be grasped in more detail. For example, for the 90° and 45° directions, the detection results by the fiber sensor 220 provided midway from the central displacement sensor 210c to the peripheral displacement sensor 210e can be used to supplement the detection results between the displacement sensors 210 in each direction. Furthermore, the fiber sensor 220 is also disposed on the center line in an intermediate direction between the 90° and 45° directions. By using the detection results by the fiber sensor 220 in this intermediate direction, the behavior of the bonding wave can be grasped in more detail.

[0081] The detection results of the displacement sensor 210 and the fiber sensor 220 are output to the control unit 70. The control unit 70 controls the operations of the first to fifth suction units 181 to 185 based on the detection results of the displacement sensor 210 and the fiber sensor 220.

[0082] For example, in the 0° direction, the bonding wave propagates from the central displacement sensor 210c through the fifth suction unit 185, the inner peripheral fiber sensor 220c, the fifth suction unit 185, the middle fiber sensor 220m, the fifth suction unit 185, the third suction unit 183, the outer peripheral displacement sensor 210e, and the first suction unit 181, in this order. A displacement sensor 210 or a fiber sensor 220 is disposed between each of the plurality of fifth suction units 185, the first suction unit 181, and the third suction unit 183. This enables the control unit 70 to perform, for example, the following real-time control. That is, after the central displacement sensor 210c detects that the second substrate S has been released from the upper chuck 141, the fifth vacuum pump 185b stops suctioning the plurality of fifth suction units 185, and the second substrate S is released from the fifth suction unit 185. The bonding wave then propagates, and the inner peripheral fiber sensor 220c and the intermediate fiber sensor 220m sequentially detect the detachment of the second substrate S from the upper chuck 141. After the intermediate fiber sensor 220m detects the detachment, the suction of the third vacuum pump 183b for the third suction unit 183 is stopped, and the second substrate S is detached from the third suction unit 183. The outer peripheral displacement sensor 210e then detects the detachment of the second substrate S from the upper chuck 141. Further thereafter, the suction of the first vacuum pump 181b for the first suction unit 181 is stopped, and the second substrate S is detached from the first suction unit 181. At the same time, this real-time control is also performed for each of the other 90° and 45° directions. As a result, even if the propagation speed of the bonding wave differs in each direction, the second substrate S can be detached from the first to fourth suction units 181 to 184 after the bonding wave has propagated until just before the first to fourth suction units 181 to 184. As a result, the collision force when the second substrate S and the first substrate W come into contact with each other can be reduced compared to when the second substrate S is released from the first to fourth suction parts 181 to 184 before the bonding wave propagates to just before the first to fourth suction parts 181 to 184. This allows for appropriate contact.

[0083] <Bonding Method> Next, a description will be given of a method for bonding the substrates W and S, which is performed using the bonding system 1 configured as above. Fig. 10 is a flowchart showing an example of main steps of such a substrate bonding process.

[0084] First, a FOUP F containing a plurality of second substrates S is Ｓ , a FOUP F containing a plurality of first substrates W; Ｗ , and empty hoop F Ｔ is placed on a predetermined FOUP placement plate 11 in the carry-in / out station 2. Then, the substrate transport device 22 Ｓ The second substrate S is then removed and transferred to the transition device 50 in the third processing block G3 of the processing station 3.

[0085] Next, the second substrate S is transported by the substrate transport device 61 to the surface modification device 30 in the first processing block G1. In the surface modification device 30, the processing gas, oxygen gas or nitrogen gas, is excited to plasma and ionized under a predetermined reduced pressure atmosphere. The oxygen ions or nitrogen ions are irradiated onto the surface Sa of the second substrate S, and the surface Sa is subjected to plasma processing. Then, the surface Sa of the second substrate S is modified (step St1 in FIG. 10 ).

[0086] Next, the second substrate S is transported by the substrate transport device 61 to the surface hydrophilization device 40 in the second processing block G2. In the surface hydrophilization device 40, pure water is supplied onto the second substrate S while the second substrate S held by the spin chuck is being rotated. The supplied pure water then diffuses over the surface Sa of the second substrate S, and hydroxyl groups (silanol groups) adhere to the surface Sa of the second substrate S, which has been modified in the surface modification device 30, thereby hydrophilizing the surface Sa. The surface Sa of the second substrate S is also cleaned by the pure water (step St2 in FIG. 10 ).

[0087] Next, the second substrate S is transported to the bonding device 41 in the second processing block G2 by the substrate transport device 61. The second substrate S loaded into the bonding device 41 is transported to the position adjustment mechanism 120 by the substrate transport mechanism 111 via the transition 110. The horizontal orientation of the second substrate S is then adjusted by the position adjustment mechanism 120 (step St3 in FIG. 10 ).

[0088] Thereafter, the second substrate S is transferred from the position adjustment mechanism 120 to the holding arm 131 of the reversing mechanism 130. Subsequently, in the transport region R1, the holding arm 131 is reversed to reverse the front and rear surfaces of the second substrate S (step St4 in FIG. 10 ). That is, the front surface Sa of the second substrate S faces downward.

[0089] Thereafter, the holding arm 131 of the inversion mechanism 130 rotates around the drive unit 133 and moves below the upper chuck 141. Then, the second substrate S is transferred from the inversion mechanism 130 to the upper chuck 141. The back surface Sb of the second substrate S is sucked and held by the upper chuck 141 (step St5 in FIG. 10 ). Specifically, the first to fifth vacuum pumps 181b to 185b are operated, and the second substrate S is vacuum-suctioned by the first to fifth suction units 181 to 185, so that the second substrate S is sucked and held by the upper chuck 141.

[0090] While the second substrate S is being processed through the above-described steps St1 to St5, the first substrate W is processed following the second substrate S. First, the FOUP F is transported by the substrate transport device 22. Ｗ The first substrate W is removed from the storage unit 10 and transferred to the transition device 50 of the processing station 3 .

[0091] Next, the first substrate W is transported by the substrate transport device 61 to the surface modification device 30, where the front surface Wa of the first substrate W is modified (step St6 in FIG. 10 ). Note that the modification of the front surface Wa of the first substrate W in step St6 is similar to the above-described step St1.

[0092] Thereafter, the first substrate W is transported by the substrate transport device 61 to the surface hydrophilization device 40, where the front surface Wa of the first substrate W is hydrophilized and the front surface Wa is cleaned (step St7 in FIG. 10 ). Note that the hydrophilization and cleaning of the front surface Wa of the first substrate W in step St7 are similar to those in step St2 described above.

[0093] Thereafter, the first substrate W is transported to the bonding device 41 by the substrate transport device 61. The first substrate W carried into the bonding device 41 is transported to the position adjustment mechanism 120 by the substrate transport mechanism 111 via the transition 110. The horizontal orientation of the first substrate W is then adjusted by the position adjustment mechanism 120 (step St8 in FIG. 10 ).

[0094] Thereafter, the first substrate W is transported by the substrate transport mechanism 111 to the lower chuck 140, and its back surface Wb is suction-held by the lower chuck 140 (step St9 in FIG. 10 ). Specifically, the vacuum pumps 207 a and 207 b are operated to suction the first substrate W through the suction ports 205 a and 205 b in the suction regions 204 a and 204 b, and the first substrate W is suction-held by the lower chuck 140.

[0095] Next, the horizontal positions of the second substrate S held by the upper chuck 141 and the first substrate W held by the lower chuck 140 are adjusted. Specifically, the first lower chuck moving unit 164 and the second lower chuck moving unit 166 move the lower chuck 140 horizontally (in the X and Y directions), and the upper imaging unit 151 sequentially captures images of predetermined reference points on the surface Wa of the first substrate W. At the same time, the lower imaging unit 161 sequentially captures images of predetermined reference points on the surface Sa of the second substrate S. The captured images are output to the control unit 70. Based on the images captured by the upper imaging unit 151 and the lower imaging unit 161, the control unit 70 moves the lower chuck 140 to a position where the reference points on the second substrate S and the first substrate W coincide with each other. The movement of the lower chuck 140 is performed by the first lower chuck moving unit 164 and the second lower chuck moving unit 166. In this way, the horizontal positions of the second substrate S and the first substrate W are adjusted (step St10 in FIG. 10).

[0096] In step St10, the lower chuck 140 is moved horizontally as described above, and the lower chuck 140 is rotated by the first lower chuck moving unit 164, thereby adjusting the rotational position of the lower chuck 140 (the orientation of the lower chuck 140).

[0097] Thereafter, the lower chuck 140 is moved vertically upward by the first lower chuck moving part 164. Then, the vertical positions of the upper chuck 141 and the lower chuck 140 are adjusted, and the vertical positions of the second substrate S held by the upper chuck 141 and the first substrate W held by the lower chuck 140 are adjusted (step St11 in FIG. 10 ). The distance between the surface Wa of the first substrate W and the surface Sa of the second substrate S is adjusted to a predetermined distance, for example, 20 μm to 400 μm. Then, the second substrate S and the first substrate W are disposed opposite each other at predetermined positions, as shown in FIG. 10 .

[0098] Next, the second substrate S held by the upper chuck 141 and the first substrate W held by the lower chuck 140 are bonded together.

[0099] In this embodiment, a case will be described in which the timing of stopping suction by the first to fifth suction units 181 to 185 is controlled in real time so as to make the bonding wave uniform as described above. For the sake of convenience, the timing of stopping suction by the first and third suction units 181 and 183 in the 90° direction will be described, but the same applies to the control of the timing of stopping suction by the second and fourth suction units 182 and 184 in the 45° direction.

[0100] Note that the bonding process is not limited to real-time control, and the timing for stopping suction by the first to fifth suction units 181 to 185 may be set in advance. That is, for example, the displacement sensor 210 and the fiber sensor 220 detect the propagation of the bonding wave for the second substrate S of the previous lot. Then, based on the detection result, the timing for stopping suction by the first to fifth suction units 181 to 185 for the second substrate S of the current lot can be set.

[0101] First, the control unit 70 outputs a lowering command to the pushing unit 190 (St12 in FIG. 9 ). Based on this lowering command, the pushing unit 190 lowers the actuator unit 191 using the cylinder unit 192. As the actuator unit 191 lowers, the striker 193 contacts the center of the back surface Sb of the second substrate S (St13 in FIG. 9 ). The striker 193 then presses the center Sc of the second substrate S downward (St14 in FIG. 9 ). Then, as shown in FIG. 11 , the striker 193 presses the center of the second substrate S against the center We of the first substrate W (St15 in FIG. 9 ). At this time, the center displacement sensor 210c detects that the front surface Sa of the second substrate S has been released from the upper chuck 141. After the release is detected, the fifth vacuum pump 185b is stopped, and the suction of the second substrate S by the fifth suction unit 185 is stopped. At the same time, the first and third vacuum pumps 181b, 183b are kept operating to continue suction at the first and third suction units 181, 183. Then, even when the striker 193 presses the center Sc of the second substrate S, the outer periphery of the second substrate S can be held by the upper chuck 141. Information on the detection result of the center displacement sensor 210c is output to, for example, the control unit 70, and is used to set the timing for stopping suction at the first to fifth suction units 181 to 185 in the bonding process of the next lot.

[0102] When the center Sc of the second substrate S and the center Wc of the first substrate W are brought into contact and pressed against each other, bonding between the centers Sc and Wc begins (the thick line in FIG. 11 ). That is, because the surface Sa of the second substrate S and the surface Wa of the first substrate W are modified at St1 and St6, respectively, van der Waals forces (intermolecular forces) are first generated between the surfaces Wa and Sa, bonding the surfaces Wa and Sa together. Furthermore, because the surface Sa of the second substrate S and the surface Wa of the first substrate W are hydrophilized at St2 and St7, respectively, the hydrophilic groups between the surfaces Wa and Sa form hydrogen bonds (intermolecular forces), firmly bonding the surfaces Wa and Sa together. Then, as shown in FIG. 12 , the bonding between the surfaces Wa and Sa due to the van der Waals forces and hydrogen bonds diffuses from the centers Sc and Wc toward the periphery (St16 in FIG. 9 ).

[0103] Thereafter, a bonding wave in which the bonding area A expands from the center toward the outer periphery is generated between the second substrate S and the first substrate W. As the bonding wave propagates, the inner peripheral fiber sensor 220c and the middle fiber sensor 220m detect that the surface Sa of the second substrate S has been released from the upper chuck 141.

[0104] After the inner peripheral fiber sensor 220c and the intermediate fiber sensor 220m detect detachment, the operation of the third vacuum pump 183b is stopped, and suction of the second substrate S at the third suction unit 183 is stopped. At the same time, the first vacuum pump 181b is kept operating, and suction at the first suction unit 181 is continued. In one embodiment, the timing at which suction at the third suction unit 183 is stopped differs in the 45° direction from the timing at which suction of the second substrate S at the fourth suction unit 184 is stopped. Information on the detection results of the inner peripheral fiber sensor 220c and the intermediate fiber sensor 220m is output to, for example, the control unit 70, and is used to set the timing at which suction is stopped at the first to fifth suction units 181 to 185 in the bonding process of the next lot.

[0105] After the suction of the second substrate S in the third suction unit 183 stops, the bonding area A further spreads toward the outer periphery, as shown in FIG. 13 . At this time, the outer periphery displacement sensor 210e detects that the surface Sa of the second substrate S has separated from the upper chuck 141. After the separation is detected, the operation of the first vacuum pump 181b is stopped, and the suction of the second substrate S in the first suction unit 181 stops. In one embodiment, the timing at which the suction of the first suction unit 181 stops differs from the timing at which the suction of the second substrate S in the second suction unit 182 stops in the 45° direction. Information on the detection results of the outer periphery displacement sensor 210e is output to, for example, the control unit 70 and used to set the timing at which the suction of the first to fifth suction units 181 to 185 stops in the bonding process for the next lot.

[0106] Then, as shown in Figure 14, the outer periphery of the second substrate S falls onto the first substrate W, and the entire surfaces Sa of the second substrate S and Wa of the first substrate W abut, and the second substrate S and the first substrate W are bonded (St17 in Figure 9).

[0107] In one embodiment, when the outer periphery displacement sensor 210e detects that the surface Sa of the second substrate S has separated from the upper chuck 141, the outer periphery fiber sensor 220e detects whether the surface Sa of the second substrate S has separated from the upper chuck 141. For example, if the outer periphery displacement sensor 210e detects separation and the outer periphery fiber sensor 220e also detects separation at the same time, it can be determined that the bonding wave has simultaneously propagated in directions between the 90° direction and the 45° direction. Information on the detection results of the outer periphery fiber sensor 220e is output to, for example, the control unit 70 and is used to set the timing for stopping suction by the first to fifth suction units 181 to 185 in the bonding process of the next lot.

[0108] Thereafter, the actuator part 191 of the pushing part 190 is raised to the upper chuck 141. Furthermore, the operation of the vacuum pumps 207a and 207b is stopped, the vacuum pumping of the first substrate W in the suction region 204 is stopped, and the suction and holding of the first substrate W by the lower chuck 140 is stopped.

[0109] The laminated substrate T, in which the second substrate S and the first substrate W are bonded together, is transported to the transition device 51 by the substrate transport device 61, and then transferred to the desired FOUP F on the FOUP mounting plate 11 by the substrate transport device 22 of the carry-in / out station 2. Ｔ In this way, a series of processes for bonding the substrates W and S is completed.

[0110] In one embodiment, the timing at which the third suction unit 183 releases the second substrate S in the 90° direction is set earlier than the timing at which the fourth suction unit 184 releases the second substrate S in the 45° direction. Also, the timing at which the first suction unit 181 releases the second substrate S in the 90° direction is set earlier than the timing at which the second suction unit 182 releases the second substrate S in the 45° direction. This allows the timing at which the bonding region A advances to be approximately the same in the 90° direction and the 45° direction, making the bonding wave uniform. By making the bonding wave uniform, distortion of the bonded laminated substrates T can be suppressed.

[0111] In step St16, the bonding wave is monitored using the displacement sensor 210 and the fiber sensor 220 to inspect the bonding state of the second substrate S and the first substrate W. During this process, the bonding wave may become non-uniform due to various disturbances. In such cases, a warning can be issued to improve product yield. Furthermore, when the bonding wave becomes non-uniform in this manner, the timing for stopping suction by the first to fifth suction units 181 to 185 when bonding the subsequent second substrate S and first substrate W can be corrected based on the detection results of the displacement sensor 210 and the fiber sensor 220.

[0112] In one embodiment, another suction unit connected to another vacuum pump may be provided between the first suction unit 181 and the second suction unit 182. By providing this other suction unit in a direction between the 90° direction and the 45° direction, the timing of stopping suction by this other suction unit can be controlled to control the bonding wave in a direction between the 90° direction and the 45° direction. This allows for more uniform bonding waves. In one embodiment, when this other suction unit is provided, the detection result of the peripheral fiber sensor 220e can be used to control this other suction unit. For example, after the peripheral fiber sensor 220e detects that the second substrate S has been released from the upper chuck 141, the suction of this other suction unit is stopped. This allows for more precise control of the bonding wave in a direction between the 90° direction and the 45° direction.

[0113] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the components of the above-described embodiments may be arbitrarily combined. Such an arbitrary combination naturally provides the functions and effects of each of the components involved in the combination, and also provides other functions and effects that are apparent to those skilled in the art from the description of this specification.

[0114] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0115] 41 Bonding device 140 Lower chuck 141 Upper chuck 190 Pushing portion 193 Striker 210 Displacement sensor 220 Fiber sensor W First substrate S Second substrate

Claims

1. A bonding device for bonding a first substrate and a second substrate, comprising: a first holding section that suctions and holds the first substrate on its upper surface by vacuuming; a second holding section that is provided above the first holding section and suctions and holds the second substrate on its lower surface by vacuuming; a pressing member that is provided on the second holding section and presses the center of the second substrate; a plurality of first detection sections and a plurality of second detection sections that are provided on the second holding section and detect the detachment of the second substrate from the second holding section, wherein the first detection sections comprise displacement sensors that can detect the distance between the second holding section and the second substrate when the second substrate has detached from the second holding section at least at positions corresponding to the first detection sections; and the second detection sections comprise fiber sensors that can detect whether the second substrate has detached from the second holding section at least at positions corresponding to the second detection sections.

2. The bonding device according to claim 1, wherein the second holding unit has a plurality of suction units that come into contact with the second substrate and vacuum-suck the second substrate, and the bonding device has a control unit that controls the suction units based on the detection results of the first detection unit and the second detection unit.

3. The joining device described in claim 2, wherein the first detection unit comprises a central displacement sensor provided at the center of the second holding unit, and a peripheral displacement sensor provided on the concentric circumference of the second holding unit at the outer periphery of the second holding unit, and at least some of the second detection units are provided in multiple locations closer to the outer periphery than the central displacement sensor and closer to the center than the peripheral displacement sensor.

4. A joining device as described in claim 3, wherein at least a portion of the second detection section is provided on the center line of the second holding section passing through the central displacement sensor and the outer peripheral displacement sensor, and on a concentric circumference of the second holding section.

5. The joining device according to claim 3, wherein the central displacement sensor is a measuring unit provided in a pushing unit that controls the movement of the pushing member and measures the distance traveled by the pushing member, and the peripheral displacement sensor is either a capacitance sensor, a distance measuring sensor or a fluid sensor.

6. The joining device according to claim 3, wherein the suction unit comprises: a first suction unit provided outside the outer periphery displacement sensor and at a 90° angle from the second holding unit; a second suction unit provided outside the outer periphery displacement sensor and at a 45° angle from the second holding unit; a third suction unit provided between the outer periphery displacement sensor and the second detection unit and at a 90° angle from the second holding unit; a fourth suction unit provided between the outer periphery displacement sensor and the second detection unit and at a 45° angle from the second holding unit; and a fifth suction unit provided between the second detection unit and the central displacement sensor; and wherein the first to fifth suction units are configured so that suction can be controlled to stop at different times.

7. The joining device according to claim 6, wherein at least eight of the outer peripheral displacement sensors are provided in the 90° and 45° directions of the second holding portion.

8. The control unit executes the following controls in this order, with respect to a 90° direction of the second holding unit: detecting the detachment of the second substrate from the second holding unit with the central displacement sensor; stopping the suction of the fifth suction unit and detaching the second substrate from the fifth suction unit; detecting the detachment of the second substrate from the second holding unit with the second detection unit; stopping the suction of the third suction unit and detaching the second substrate from the third suction unit; detecting the detachment of the second substrate from the second holding unit with the outer periphery displacement sensor; stopping the suction of the first suction unit and detaching the second substrate from the first suction unit; and with respect to a 45° direction of the second holding unit: detecting the detachment of the second substrate from the second holding unit with the central displacement sensor; stopping the suction of the fifth suction unit and detaching the second substrate from the fifth suction unit; and detecting the detachment of the second substrate from the second holding unit with the second detection unit.

8. The bonding device according to claim 7, wherein the control includes, in this order: stopping suction of the fourth suction unit and releasing the second substrate from the fourth suction unit; detecting the release of the second substrate from the second holding unit with the outer periphery displacement sensor; and stopping suction of the second suction unit and releasing the second substrate from the second suction unit.

9. A joining device according to any one of claims 1 to 8, wherein the second detection unit comprises a white fiber sensor.

10. A bonding method for bonding a first substrate and a second substrate using a bonding device, the bonding device comprising: a first holding section that suctions and holds the first substrate on its upper surface; a second holding section that is provided above the first holding section and suctions and holds the second substrate on its lower surface; a pressing member that is provided on the second holding section and presses the center of the second substrate; a plurality of first detection sections and a plurality of second detection sections that are provided on the second holding section and detect detachment of the second substrate from the second holding section; the second holding section comprising a plurality of suction sections that come into contact with the second substrate and suctions and suctions the second substrate; the first detection sections comprising a displacement sensor that can detect the distance between the second holding section and the second substrate when the second substrate has detached from the second holding section at least at a position corresponding to the first detection section; and the second detection section comprising a fiber sensor that can detect whether the second substrate has detached from the second holding section at least at a position corresponding to the second detection section. The bonding method includes controlling the suction unit based on detection results of the first detection unit and the second detection unit.

11. The first detection unit comprises a central displacement sensor provided at the center of the second holding unit, and a peripheral displacement sensor provided on the concentric circumference of the second holding unit at the outer periphery of the second holding unit, the second detection unit is provided on the center line of the second holding unit passing through the central displacement sensor and the peripheral displacement sensor, and is provided on the concentric circumference of the second holding unit, at least eight peripheral displacement sensors are provided in 90° and 45° directions of the second holding unit, the suction unit comprises: a first suction unit provided outside the peripheral displacement sensor and at 90° from the second holding unit, a second suction unit provided outside the peripheral displacement sensor and at 45° from the second holding unit, a third suction unit provided between the peripheral displacement sensor and the second detection unit and at 90° from the second holding unit, a fourth suction unit provided between the peripheral displacement sensor and the second detection unit and at 45° from the second holding unit, and a fifth suction unit provided between the second detection unit and the central displacement sensor, and the joining method is With respect to a 90° direction of the second holding unit, the central displacement sensor detects the removal of the second substrate from the second holding unit, stops suction by the fifth suction unit and removes the second substrate from the fifth suction unit, detects the removal of the second substrate from the second holding unit with the second detection unit, stops suction by the third suction unit and removes the second substrate from the third suction unit, detects the removal of the second substrate from the second holding unit with the outer periphery displacement sensor, and stops suction by the first suction unit and removes the second substrate from the first suction unit, in this order; With respect to a 45° direction of the second holding unit, the central displacement sensor detects the removal of the second substrate from the second holding unit, stops suction by the fifth suction unit and removes the second substrate from the fifth suction unit, and detects the removal of the second substrate from the second holding unit with the second detection unit. stopping suction by the fourth suction unit and releasing the second substrate from the fourth suction unit; and detecting the release of the second substrate from the second holding unit by the outer periphery displacement sensor.the second suction unit stops suctioning the second substrate; and the second suction unit releases the second substrate from the second suction unit.

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