Substrate processing system, bonding apparatus, and bonding method

Abstract

This substrate processing system comprises: a joining device that joins substrates to each other; and a control device. The joining device is provided with: a first holding part that holds a first substrate; a second holding part that is provided below or above the first holding part and holds a second substrate; an abutting member that makes a center part of the first substrate abut a center part of the second substrate; an image capturing unit that captures an image of at least the first substrate; and a moving mechanism that relatively moves the first holding part, the second holding part, and the image capturing unit. The first substrate is provided with at least one reference point having known coordinates with the center part of the first substrate as an origin. The control device executes controls including: (a) a step for capturing an image of the first substrate and determining a virtual center part of the first substrate; (b) a step for moving the image capture center of the image capturing unit from the virtual center part to a position corresponding to the coordinates of the reference point when the virtual center part is set as the origin; (c) a step for capturing an image of the first substrate at the position moved to in step (b) and acquiring a coordinate difference between the image capture center and the reference point; (d) a step for correcting the virtual center part to obtain the center part of the first substrate; and (e) a step for making the center part of the first substrate obtained in step (d) abut the center part of the second substrate.

Description

[Technical Field]

[0001] This disclosure relates to a substrate processing system, a bonding apparatus, and a bonding method. [Background technology]

[0002] Patent Document 1 discloses a bonding apparatus for joining wafers together. This bonding apparatus has an upper chuck on its lower surface that holds the upper wafer by vacuum suction, and a lower chuck provided below the upper chuck that holds the lower wafer by vacuum suction on its upper surface, and bonds two wafers that are positioned facing each other vertically. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-095579 [Overview of the project] [Problems that the invention aims to solve]

[0004] The technology described herein enables proper bonding of substrates. [Means for solving the problem]

[0005] One aspect of the present disclosure is a substrate processing system comprising a bonding device for bonding substrates together, and a control device, wherein the bonding device comprises a first holding portion for holding a first substrate, a second holding portion provided below or above the first holding portion for holding a second substrate, a contact member for bringing the center of the first substrate into contact with the center of the second substrate, an imaging portion for imaging at least the first substrate, and a moving mechanism for relatively moving the first holding portion, the second holding portion, and the imaging portion, wherein the first substrate has at least one reference point whose coordinates are known with respect to the center of the first substrate as the origin, and the control device is The control includes the steps of: (a) imaging the first substrate to determine the virtual center of the first substrate; (b) moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin; (c) imaging the first substrate at the position moved in step (b) to obtain the coordinate difference between the imaging center and the reference point; (d) correcting the virtual center to determine the center of the first substrate; and (e) bringing the center of the first substrate determined in step (d) into contact with the center of the second substrate. [Effects of the Invention]

[0006] According to this disclosure, substrates can be properly bonded. [Brief explanation of the drawing]

[0007] [Figure 1] This is a plan view showing a schematic configuration of the joining system according to this embodiment. [Figure 2] This is a side view showing a schematic of the internal configuration of the joining system according to this embodiment. [Figure 3] This is a side view illustrating the schematic configuration of the device wafer and support wafer. [Figure 4] This is a plan view showing a schematic configuration of the device wafer. [Figure 5] This is a plan view showing a schematic configuration of the support wafer. [Figure 6] This is a cross-sectional view showing a schematic configuration of the joining device. [Figure 7] This is a longitudinal cross-sectional view schematically showing the configuration of a bonding apparatus. [Figure 8] This is a longitudinal cross-sectional view schematically showing the configurations of an upper chuck and a lower chuck. [Figure 9] This is a flowchart showing the main steps of a bonding method. [Figure 10] This is a flowchart showing the main steps of a first sub-process. [Figure 11] This is an explanatory diagram schematically showing first imaging data in the first sub-process. [Figure 12] This is an explanatory diagram schematically showing movement, coordinate difference, and correction in the first sub-process. [Figure 13] This is an explanatory diagram schematically showing second imaging data in the first sub-process. [Figure 14] This is an explanatory diagram schematically showing second imaging data in the first sub-process. [Figure 15] This is a flowchart showing the main steps of a second sub-process. [Figure 16] This is an explanatory diagram schematically showing third imaging data in the second sub-process. [Figure 17] This is an explanatory diagram showing each state in the main steps of the second sub-process in chronological order. [Figure 18] This is an explanatory diagram schematically showing movement, coordinate difference, and correction in the second sub-process. [Figure 19] This is an explanatory diagram schematically showing movement, coordinate difference, and correction in the second sub-process. [Figure 20] This is an explanatory diagram showing the main steps of the bonding method. [Figure 21] This is a side view schematically showing the configuration of an inspection apparatus. [Figure 22] This is a flowchart showing the main steps of an inspection method. [Figure 23] This is an explanatory diagram schematically showing an example of infrared imaging data in the inspection method. [Figure 24] This is an explanatory diagram schematically showing another example of infrared imaging data in the inspection method. [Modes for carrying out the invention]

[0008] In 3D integration technology, which involves stacking semiconductor devices in a three-dimensional structure, two semiconductor wafers (hereinafter referred to as "wafers") are joined together. In the joining process, the wafers are joined together, for example, by van der Waals forces and hydrogen bonds (intermolecular forces).

[0009] In the bonding apparatus disclosed in Patent Document 1, first, the center of the upper wafer, which is held by suction on the upper chuck, is pressed down by a pushing member and brought into contact with the center of the lower wafer, which is held by suction on the lower chuck. When this happens, bonding by the intermolecular forces described above begins between the pressed center of the upper wafer and the center of the lower wafer. Next, the vacuum of the upper wafer is stopped from the center outward, and the upper wafer falls onto the lower wafer in sequence and comes into contact with it, and the bonding by the intermolecular forces between the surfaces described above expands in sequence. In this way, the surfaces of the upper wafer and the lower wafer come into contact over their entire surfaces, and the upper wafer and the lower wafer are bonded together.

[0010] However, the bonding apparatus disclosed in Patent Document 1 does not take into consideration how to properly determine the center points of the upper and lower wafers that serve as the reference for contact. Furthermore, it does not take into consideration how to inspect the bonding state of the wafers.

[0011] To properly join the wafers, it is conceivable to image the upper and lower wafers using an imaging device prior to contact and determine their centers using image analysis with a known algorithm. However, depending on the condition of the upper or lower wafer, such as the outer periphery or notch, image analysis using a known algorithm may not be able to properly determine the center. Therefore, there is room for improvement in conventional wafer joining processes.

[0012] The technology described herein provides for the proper joining of substrates. The substrate processing system, joining apparatus, joining method, and inspection method according to this embodiment will be described below with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, thus omitting redundant explanations.

[0013] <Configuration of the substrate processing system> First, the configuration of the substrate processing system according to this embodiment will be described. Figure 1 is a plan view showing a schematic of the configuration of the substrate processing system 1. Figure 2 is a side view showing a schematic of the internal configuration of the substrate processing system 1. In the following, in order to clarify the positional relationships, the X-axis, Y-axis, and Z-axis directions are defined as being orthogonal to each other, and the positive Z-axis direction is defined as the vertically upward direction.

[0014] In the substrate processing system 1, a polymerized substrate is obtained by joining two substrates, a first substrate and a second substrate, as shown in Figure 3. In the following description, the first substrate and the second substrate together may be simply referred to as a "wafer." In this embodiment, the first substrate is a device wafer W as shown in Figure 4, and the second substrate is a support wafer S as shown in Figure 5. The polymerized wafer T is an example of a polymerized substrate. On the device wafer W, the side joined to the support wafer S is called the surface Wa, and the side opposite to surface Wa is called the back surface Wb. Similarly, on the support wafer S, the side joined to the device wafer W is called the surface Sa, and the side opposite to surface Sa is called the back surface Sb.

[0015] The device wafer W is a semiconductor wafer, such as a silicon substrate, and has a device layer D formed on its surface Wa that includes multiple circuits. A notch Wn is formed on the outer periphery We of the device wafer W. In addition, a first reference point P1 and a second reference point P2 are formed such that their coordinate positions are known, with the center Wc of the device wafer W as the origin. In one embodiment, the first reference point P1 and the second reference point P2 are alignment marks formed during pattern formation when the device layer D is formed. In another embodiment, the first reference point P1 and the second reference point P2 are desired points on the scribe line Ws.

[0016] Furthermore, as shown in Figure 4, the device wafer W is subjected to a dicing process and divided into multiple dies Wd by scribe lines Ws (sometimes called streets). In this embodiment, in a plan view, the dies Wd are rectangular in shape, and the scribe lines Ws are formed in a grid pattern. Circuits of the device layer D are formed on the surface of the dies Wd, and the dies Wd constitute the circuit formation region in this disclosure. No circuits are formed on the scribe lines Ws, and the scribe lines Ws constitute the non-circuit formation region in this disclosure. In addition, no circuits are formed on the outer peripheral area We of the device wafer W radially outside these dies Wd and scribe lines Ws.

[0017] The support wafer S is a wafer that supports the device wafer W. The support wafer S is made of a material that transmits infrared light, such as a silicon wafer. A notch Sn is formed on the outer periphery Se of the support wafer S.

[0018] The combination of two substrates joined by the substrate processing system 1 is not limited to the above, and any desired combination of substrates can be joined. In one embodiment, both the first substrate and the second substrate are device wafers W. In another embodiment, the first substrate is a device wafer W, and the second substrate is an epitaxial wafer.

[0019] In the following description, it is assumed that the device wafer W as the first substrate is disposed on the lower side, and the support wafer S as the second substrate is disposed on the upper side. However, such an arrangement is for convenience of description, and is not limited thereto.

[0020] As shown in FIG. 1, the substrate processing system 1 includes, for example, cassettes C each capable of accommodating a plurality of wafers W, S and a plurality of bonded wafers T with respect to the outside W , C S , C T has a configuration in which a loading / unloading station 2 through which the wafers are loaded and unloaded, and a processing station 3 provided with various processing apparatuses for performing desired processing on the wafers W, S and the bonded wafers T are integrally connected. Also, in one embodiment, an inspection station 4 is provided adjacent to the processing station 3.

[0021] The loading / unloading station 2 is provided with a cassette mounting table 10. The cassette mounting table 10 is provided with a plurality of, for example, four cassette mounting plates 11. The cassette mounting plates 11 are arranged in a line in the horizontal Y-axis direction (the vertical direction in FIG. 1). These cassette mounting plates 11 are used for cassettes C for the outside of the substrate processing system 1 W , C S , C T can place the cassettes C when loading and unloading W , C S , C T . In this way, the loading / unloading station 2 is configured to be capable of holding a plurality of support wafers S, a plurality of device wafers W, and a plurality of bonded wafers T. The number of the cassette mounting plates 11 is not limited to the present embodiment, and can be set arbitrarily. Further, one of the cassettes may be used for collecting abnormal wafers. That is, the cassette is a cassette capable of separating a wafer in which an abnormality has occurred in the bonding between the support wafer S and the device wafer W due to various factors from other normal bonded wafers T. In the present embodiment, among the plurality of cassettes C T , one cassette C T is used for collecting abnormal wafers, and the other cassettes C T are used for accommodating normal bonded wafers T.

[0022] The loading / unloading station 2 is provided with a wafer transport section 20 adjacent to the cassette mounting table 10. The wafer transport section 20 is provided with a wafer transport device 22 that is movable along a transport path 21 extending in the Y-axis direction. The wafer transport device 22 is also movable in the vertical direction and around the vertical axis (Z-axis), and transports cassettes C on each cassette mounting plate 11. W , C S , C T This allows for the transfer of wafers W, S, and polymerized wafer T between the transition devices 50 and 51 of the third processing block G3 of processing station 3, which will be described later.

[0023] Processing station 3 is equipped with multiple processing blocks, such as three processing blocks G1, G2, and G3, each containing various devices. For example, the first processing block G1 is located on the front side of processing station 3 (negative Y-axis direction in Figure 1), and the second processing block G2 is located on the rear side of processing station 3 (positive Y-axis direction in Figure 1). In addition, the third processing block G3 is located on the loading / unloading station 2 side of processing station 3 (negative X-axis direction in Figure 1).

[0024] The first processing block G1 is equipped with a surface modification apparatus 30 for modifying the surface Wa and Sa of wafers W and S. In the surface modification apparatus 30, for example, under a reduced pressure atmosphere, oxygen gas or nitrogen gas, which is the processing gas, is excited, plasma-generated, and ionized. These oxygen ions or nitrogen ions are irradiated onto the surface Wa and Sa, causing the surface Wa and Sa to be plasma-treated and modified.

[0025] In the second processing block G2, a surface hydrophilization device 40, which hydrophilizes the surfaces Wa and Sa of wafers W and S using pure water and cleans the surfaces Wa and Sa, and a bonding device 41, which bonds wafers W and S, are arranged in this order along the horizontal X-axis direction from the loading / unloading station 2 side. The configuration of the bonding device 41 will be described later.

[0026] In the surface hydrophilization apparatus 40, for example, while rotating wafers W and S held in a spin chuck, pure water is supplied onto the wafers W and S. As a result, the supplied pure water diffuses over the surfaces Wa and Sa of wafers W and S, and the surfaces Wa and Sa become hydrophilic.

[0027] In the third processing block G3, as shown in Figure 2, transition devices 50 and 51 for wafers W, S, and polymerized wafer T are provided in two stages from bottom to top.

[0028] As shown in Figure 1, a wafer transport area 60 is formed in the region enclosed by the first processing block G1 to the third processing block G3. A wafer transport device 61, for example, is arranged in the wafer transport area 60.

[0029] The wafer transport device 61 has a transport arm that can move freely around, for example, the vertical direction, the horizontal direction (X-axis direction, Y-axis direction), and the vertical axis (Z-axis). The wafer transport device 61 can move within the wafer transport area 60 and transport wafers W, S, and polymerized wafer T to desired devices within the surrounding first processing block G1, second processing block G2, and third processing block G3. The wafer transport device 61 can also transport wafers W, S, and polymerized wafer T to the inspection station 4.

[0030] The substrate processing system 1 described above is provided with a control device 70 as a control unit. The control device 70 processes computer-executable instructions that cause the substrate processing system 1 to perform the various processes described herein. The control device 70 may be configured to control each element of the substrate processing system 1 to perform the various processes described herein. In one embodiment, some or all of the control device 70 may be included in the substrate processing system 1. The control device 70 may include a processing unit, a storage unit, and a communication interface. The control device 70 is implemented, for example, by a computer. The processing unit may be configured to read a program from the storage unit that provides logic or routines that enable various control operations, and to perform various control operations by executing the read program. This program may be stored in the storage unit in advance, or it may be obtained via a medium when needed. The obtained program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium may be various storage media H that are readable by a computer, or it may be a communication line connected to a communication interface. The storage media H may be temporary or permanent. The processing unit may be a CPU (Central Processing Unit), or it may be one or more circuits. The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface may communicate with the board processing system 1 via a communication line such as a LAN (Local Area Network).

[0031] In one embodiment, the inspection station 4 includes an inspection device 80. Details of the inspection device 80 will be described later.

[0032] <Configuration of the joining device> Next, the configuration of the joining device 41 described above will be explained. Figure 4 is a cross-sectional view showing a schematic of the configuration of the joining device 41. Figure 5 is a vertical cross-sectional view showing a schematic of the configuration of the joining device 41.

[0033] (Overall configuration of the joining device) As shown in Figures 4 and 5, the bonding apparatus 41 has a processing container 100 that can be sealed inside. On the side of the processing container 100 facing the wafer transport area 60, an inlet / outlet 101 for wafers W, S, and polymerized wafer T is formed, and an opening / closing shutter 102 is provided at the inlet / outlet 101.

[0034] The interior of the processing container 100 is divided into a transport area R1 and a processing area R2 by an inner wall 103. The aforementioned loading / unloading port 101 is formed on the side of the processing container 100 in the transport area R1. In addition, loading / unloading ports 104 for wafers W, S, and polymerized wafer T are also formed in the inner wall 103.

[0035] A transition 110 is provided on the positive Y-axis side of the transport region R1 for temporarily placing wafers W, S, and polymerized wafer T. The transition 110 is formed in, for example, two stages, and can simultaneously place any two of wafers W, S, and polymerized wafer T.

[0036] A wafer transport mechanism 111 is provided in the transport area R1. The wafer transport mechanism 111 has a transport arm that can move, for example, around the vertical, horizontal (X-axis direction, Y-axis direction) and vertical axis (Z-axis). The wafer transport mechanism 111 can transport wafers W, S, and polymerized wafers T within the transport area R1 or between the transport area R1 and the processing area R2.

[0037] A position adjustment mechanism 120 for adjusting the horizontal orientation of wafers W and S is provided on the negative Y-axis side of the transport area R1. The position adjustment mechanism 120 includes a base 121 equipped with a holding part (not shown) for holding and rotating wafers W and S, and a detection unit 122 for detecting the position of the notch portion of wafers W and S. The position adjustment mechanism 120 adjusts the horizontal orientation of wafers W and S by adjusting the position of the notch portion of wafers W and S by detecting the position of the notch portion of wafers W and S with the detection unit 122 while rotating wafers W and S held on the base 121. The method of holding wafers W and S on the base 121 is not particularly limited, and various methods such as a pin chuck method or a spin chuck method can be used.

[0038] Furthermore, the transport region R1 is provided with a reversal mechanism 130 for reversing the front and back surfaces of the support wafer S. The reversal mechanism 130 has a holding arm 131 for holding the support wafer S. The holding arm 131 extends in the horizontal direction (X-axis direction). The holding arm 131 is also provided with, for example, four holding members 132 for holding the support wafer S.

[0039] The holding arm 131 is supported by a drive unit 133, which is 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 in the horizontal direction (X-axis direction). Below the drive unit 133, another drive unit (not shown), which is equipped with, for example, a motor, is provided. This other drive unit allows the drive unit 133 to move vertically along a support column 134 that extends vertically. In this way, the drive unit 133 allows the support wafer S held by the holding member 132 to rotate around a horizontal axis and move vertically and horizontally. Furthermore, the support wafer S held by the holding member 132 can rotate around the drive unit 133 and move between the position adjustment mechanism 120 and the upper chuck 141, which will be described later.

[0040] The processing area R2 is provided with a lower chuck 140 as a first holding part for placing and holding the device wafer W on its upper surface, and an upper chuck 141 as a second holding part for holding the support wafer S on its lower surface. The lower chuck 140 is located below the upper chuck 141 and is configured to be positioned opposite the upper chuck 141. That is, the device wafer W held by the lower chuck 140 and the support wafer S held by the upper chuck 141 can be positioned opposite each other.

[0041] The upper chuck 141 is supported by an upper chuck stage 150 located above it. The upper chuck stage 150 is provided with an upper imaging unit 151 for imaging the surface Wa of the device wafer W held by the lower chuck 140. That is, the upper imaging unit 151 is located adjacent to the upper chuck 141. For example, a CCD camera is used for the upper imaging unit 151.

[0042] The upper chuck stage 150 is supported above the upper chuck stage 150 by a rotating part 153, which is a moving mechanism provided on the ceiling surface of the processing container 100 via a plurality of support members 152. The rotating part 153 is configured to rotate the upper chuck stage 150 and the upper chuck 141 around a vertical axis (Z axis). The rotating part 153 incorporates, for example, a driver 153a, which is a servo driver, and a motor 153b, which is a servo motor.

[0043] The rotating section 153 is equipped with a linear scale 154 as a measuring section. The linear scale 154 measures the θ azimuth angle (position in the Z-axis rotation direction) of the upper chuck 141. Although the linear scale 154 measures the θ azimuth angle of the rotating section 153, the rotating section 153, the support member 152, the upper chuck stage 150, and the upper chuck 141 are rigid bodies, so it effectively measures the θ azimuth angle of the upper chuck 141.

[0044] Furthermore, 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.

[0045] The lower chuck 140 is supported by a lower chuck stage 160 located below it. The lower chuck stage 160 is provided with a lower imaging unit 161 that images the surface Sa of the support wafer S held by the upper chuck 141. That is, the lower imaging unit 161 is located adjacent to the lower chuck 140. For example, a CCD camera is used in the lower imaging unit 161.

[0046] The lower chuck stage 160 is supported by a first lower chuck moving part 164, which is a moving mechanism located below the lower chuck stage 160. The first lower chuck moving part 164 is configured to move the lower chuck 140 in the horizontal direction (X-axis direction), as will be described later. The first lower chuck moving part 164 is also configured to move the lower chuck 140 in the vertical direction (Z-axis direction). The first lower chuck moving part 164 incorporates, for example, a driver 164a, which is a servo driver, and a motor 164b, which is a servo motor. In this embodiment, the first lower chuck moving part 164 moves the lower chuck 140 in the X-axis direction and the Z-axis direction, but separate moving parts may be provided for moving the lower chuck 140 in the X-axis direction and for moving it in the Z-axis direction.

[0047] The first lower chuck moving part 164 is provided on the lower side of the first lower chuck moving part 164 and is attached to a pair of rails 165, 165 that extend horizontally (in the X-axis direction). The first lower chuck moving part 164 is configured to be movable along the rails 165.

[0048] A pair of rails 165, 165 are arranged on a second lower chuck moving section 166, which serves as a moving mechanism. The second lower chuck moving section 166 is provided on the lower side of the second lower chuck moving section 166 and is attached to a pair of rails 167, 167 that extend horizontally (in the Y-axis direction). The second lower chuck moving section 166 is configured to move freely along the rails 167, that is, to move the lower chuck 140 horizontally (in the Y-axis direction). The second lower chuck moving section 166 incorporates, for example, a driver 166a, which is a servo driver, and a motor 166b, which is a servo motor. The pair of rails 167, 167 are arranged on a mounting base 168 provided on the bottom surface of the processing container 100.

[0049] Furthermore, the configuration for moving the lower chuck 140 in the X-axis, Y-axis, and Z-axis directions, and the configuration for measuring the X-axis, Y-axis, and Z-axis positions of the lower chuck 140, are not limited to this embodiment and can be designed arbitrarily.

[0050] (Consists of an upper zipper and a lower zipper) Next, the detailed configuration of the lower chuck 140 and upper chuck 141 of the joining device 41 will be described. Figure 6 is a longitudinal cross-sectional view showing a schematic configuration of the upper chuck 141 and lower chuck 140.

[0051] As shown in Figure 6, the upper chuck 141 employs a pin chuck system. The upper chuck 141 has a main body portion 170 with a diameter greater than or equal to the diameter of the support wafer S in a plan view. Multiple pins 171 that contact the back surface Wb of the support wafer S are provided on the lower surface of the main body portion 170. In addition, outer ribs 172 are provided on the outer periphery of the lower surface of the main body portion 170, having the same height as the pins 171 and supporting the outer periphery of the back surface Wb of the support wafer S. The outer ribs 172 are provided in an annular shape on the outside of the multiple pins 171.

[0052] Furthermore, on the lower surface of the main body 170, an inner rib 173 is provided, which is the same height as the pin 171 and supports the back surface Wb of the support wafer S, inside the outer rib 172. The inner rib 173 is provided in an annular shape concentric with the outer rib 172. The region 174 inside the outer rib 172 (hereinafter sometimes referred to as the suction region 174) is divided into a first suction region 174a inside the inner rib 173 and a second suction region 174b outside the inner rib 173.

[0053] On the lower surface of the main body 170, a first suction port 175a is formed in the first suction region 174a for evacuating the support wafer S. For example, four first suction ports 175a are formed in the first suction region 174a. A first suction tube 176a, provided inside the main body 170, is connected to the first suction ports 175a. Furthermore, a first vacuum pump 177a is connected to the first suction tube 176a.

[0054] Furthermore, a second suction port 175b for evacuating the support wafer S is formed on the lower surface of the main body 170 in the second suction region 174b. The second suction port 175b is formed in two locations, for example, in the second suction region 174b. A second suction tube 176b, which is provided inside the main body 170, is connected to the second suction port 175b. A second vacuum pump 177b is further connected to the second suction tube 176b.

[0055] Then, the suction regions 174a and 174b, which are formed by being surrounded by the support wafer S, the main body 170, and the outer ribs 172, are evacuated from the suction ports 175a and 175b, respectively, thereby reducing the pressure in the suction regions 174a and 174b. At this time, since the atmosphere outside the suction regions 174a and 174b is atmospheric pressure, the support wafer S is pushed towards the suction regions 174a and 174b by the atmospheric pressure by the amount of the pressure reduction, and the support wafer S is held by suction in the upper chuck 141. The upper chuck 141 is also configured to be able to evacuate the support wafer S separately for the first suction region 174a and the second suction region 174b.

[0056] A through-hole 178 is formed in the center of the main body 170 of the upper chuck 141 and the center of the upper chuck stage 150, penetrating the main body 170 and the upper chuck stage 150 in the thickness direction. The center of the main body 170 corresponds to the center of the support wafer S that is held by the upper chuck 141. The tip of the actuator portion 181 of the pushing portion 180, which will be described later, is inserted through the through-hole 178.

[0057] The upper surface of the upper chuck stage 150 is provided with a pressing portion 180 that presses against the center of the support wafer S. The pressing portion 180 has an actuator portion 181 and a cylinder portion 182 as contact members.

[0058] The actuator unit 181 generates a constant pressure in a specific direction using air supplied from an electro-pneumatic regulator (not shown), and can generate a constant pressure regardless of the position of the point of application of the pressure. The air from the electro-pneumatic regulator allows the actuator unit 181 to contact the center of the support wafer S and control the pressing load applied to the center of the support wafer S. Furthermore, the tip of the actuator unit 181 is able to move vertically up and down by passing through the through hole 178 using air from the electro-pneumatic regulator.

[0059] The actuator section 181 is supported by the cylinder section 182. The cylinder section 182 can move the actuator section 181 vertically by a drive unit, for example, which has a built-in motor.

[0060] As described above, the pushing unit 180 controls the pressing load with the actuator unit 181 and controls the movement of the actuator unit 181 with the cylinder unit 182. Furthermore, the pushing unit 180 can press the center of the support wafer S against the center of the device wafer W when joining wafers W and S, as will be described later.

[0061] The lower chuck 140 employs a pin chuck system, similar to the upper chuck 141. The lower chuck 140 has a main body 190 with a diameter greater than or equal to the diameter of the device wafer W in a plan view. Multiple pins 191 that contact the back surface Sb of the device wafer W are provided on the upper surface of the main body 190. In addition, outer ribs 192 are provided on the outer periphery of the upper surface of the main body 190, having the same height as the pins 191 and supporting the outer periphery of the back surface Sb of the device wafer W. The outer ribs 192 are provided in an annular shape outside the multiple pins 191.

[0062] Furthermore, on the upper surface of the main body 190, an inner rib 193 is provided, which is the same height as the pin 191 and supports the back surface Sb of the device wafer W, inside the outer rib 192. The inner rib 193 is provided in an annular shape concentric with the outer rib 192. The region 194 inside the outer rib 192 (hereinafter sometimes referred to as the suction region 194) is divided into a first suction region 194a inside the inner rib 193 and a second suction region 194b outside the inner rib 193.

[0063] A first suction port 195a for vacuuming the device wafer W is formed on the upper surface of the main body 190 in the first suction region 194a. The first suction port 195a is formed in one location in the first suction region 194a, for example. A first suction tube 196a, which is provided inside the main body 190, is connected to the first suction port 195a. Furthermore, a first vacuum pump 197a is connected to the first suction tube 196a.

[0064] Furthermore, a second suction port 195b for evacuating the device wafer W is formed on the upper surface of the main body 190 in the second suction region 194b. The second suction port 195b is formed in two locations, for example, in the second suction region 194b. A second suction tube 196b, which is provided inside the main body 190, is connected to the second suction port 195b. A second vacuum pump 197b is further connected to the second suction tube 196b.

[0065] Then, the suction regions 194a and 194b, which are formed by being surrounded by the device wafer W, the main body 190, and the outer ribs 192, are evacuated from the suction ports 195a and 195b, respectively, thereby reducing the pressure in the suction regions 194a and 194b. At this time, since the atmosphere outside the suction regions 194a and 194b is atmospheric pressure, the device wafer W is pushed towards the suction regions 194a and 194b by the atmospheric pressure by the amount of the reduced pressure, and the device wafer W is held by suction in the lower chuck 140. The lower chuck 140 is also configured to allow the device wafer W to be evacuated separately for the first suction region 194a and the second suction region 194b.

[0066] In the lower chuck 140, for example, three through holes (not shown) are formed near the center of the main body 190, penetrating the main body 190 in the thickness direction. A lifting pin, located below the first lower chuck moving part 164, is inserted through these through holes.

[0067] Guide members (not shown) are provided on the outer periphery of the main body 190 to prevent the wafers W, S, and polymerized wafer T from flying out or sliding out of the lower chuck 140. Multiple guide members are provided on the outer periphery of the main body 190 at equal intervals, for example, at four locations.

[0068] The operation of each part of the joining device 41 is controlled by the control device 70 described above.

[0069] <Joining method> Next, we will describe the method for joining wafers W and S using the substrate processing system 1 configured as described above. Figure 9 is a flowchart showing the main steps of the wafer joining process.

[0070] First, there is a cassette C containing multiple device wafers W. W Cassette C containing multiple support wafers S S , and an empty cassette C T However, it is placed on the desired cassette mounting plate 11 of the loading / unloading station 2. Then, the wafer transport device 22 moves the cassette C SThe internal support wafer S is removed and transported to the transition device 50 of the third processing block G3 of the processing station 3.

[0071] Next, the support wafer S is transported by the wafer transport device 61 to the surface modification device 30 of the first processing block G1. In the surface modification device 30, under a desired reduced-pressure atmosphere, oxygen gas or nitrogen gas, which is the processing gas, is excited, plasma-generated, and ionized. These oxygen ions or nitrogen ions are irradiated onto the surface Sa of the support wafer S, and the surface Sa is plasma-treated. As a result, the surface Sa of the support wafer S is modified (St1 in Figure 9).

[0072] Next, the support wafer S is transported by the wafer 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 support wafer S while it is rotated, which is held in a spin chuck. The supplied pure water diffuses over the surface Sa of the support wafer S, and hydroxyl groups (silanol groups) adhere to the surface Sa of the support wafer S, which has been modified in the surface modification device 30, making the surface Sa hydrophilic. In addition, the surface Sa of the support wafer S is washed by the pure water (St2 in Figure 9).

[0073] Next, the support wafer S is transported by the wafer transport device 61 to the bonding device 41 in the second processing block G2. The support wafer S, once loaded into the bonding device 41, is transported via the transition 110 to the position adjustment mechanism 120 by the wafer transport mechanism 111. The position adjustment mechanism 120 then adjusts the horizontal orientation of the support wafer S (St3 in Figure 9).

[0074] Subsequently, the support wafer S is transferred from the position adjustment mechanism 120 to the holding arm 131 of the reversal mechanism 130. Then, in the transport area R1, the holding arm 131 is reversed, causing the front and back surfaces of the support wafer S to be reversed (St4 in Figure 9). That is, the front surface Sa of the support wafer S is oriented downwards.

[0075] Subsequently, the holding arm 131 of the reversing mechanism 130 rotates around the drive unit 133 and moves below the upper chuck 141. Then, the support wafer S is transferred from the reversing mechanism 130 to the upper chuck 141. The support wafer S is held by the upper chuck 141 with its back surface Wb adsorbed (St5 in Figure 9). Specifically, the vacuum pumps 177a and 177b are activated to create a vacuum around the support wafer S through the suction ports 175a and 175b in the suction regions 174a and 174b, and the support wafer S is held by the upper chuck 141 with adsorption.

[0076] While the above-described processes St1 to St5 are being performed on the support wafer S, the device wafer W is processed following the support wafer S. First, the wafer transport device 22 transfers the cassette C W The device wafer W inside is removed and transported to the transition device 50 of the processing station 3.

[0077] Next, the device wafer W is transported to the surface modification apparatus 30 by the wafer transport apparatus 61, and the surface Wa of the device wafer W is modified (St6 in Figure 9). The modification of the surface Wa of the device wafer W in St6 is the same as in St1 described above.

[0078] Subsequently, the device wafer W is transported to the surface hydrophilization device 40 by the wafer transport device 61, where the surface Wa of the device wafer W is hydrophilized and the surface Sa is cleaned (St7 in Figure 9). The hydrophilization and cleaning of the surface Wa of the device wafer W in St7 is the same as in St2 described above.

[0079] Subsequently, the device wafer W is transported to the bonding apparatus 41 by the wafer transport device 61. The device wafer W, once loaded into the bonding apparatus 41, is transported to the position adjustment mechanism 120 via the wafer transport mechanism 111 through the transition 110. The position adjustment mechanism 120 then adjusts the horizontal orientation of the device wafer W (St8 in Figure 9).

[0080] Subsequently, the device wafer W is transported to the lower chuck 140 by the wafer transport mechanism 111, and its back surface Wb is held by the lower chuck 140 (St9 in Figure 9). Specifically, the vacuum pumps 197a and 197b are activated to create a vacuum around the device wafer W in the suction regions 194a and 194b through the suction ports 195a and 195b, and the device wafer W is held by the lower chuck 140 by suction.

[0081] Next, the horizontal position of the device wafer W held in the lower chuck 140 and the support wafer S held in the upper chuck 141 is adjusted (St10 in Figure 9). In St10, the horizontal position of the device wafer W and the support wafer S is adjusted based on the center Wc of the device wafer W and the center Sc of the support wafer S, which are determined by executing the first or second subprocess described later.

[0082] In St10, the central point Sc of the support wafer S can be determined as follows, for example. First, the surface Sa of the support wafer S is imaged using the lower imaging unit 161 to acquire imaging data. Next, the central point Sc of the support wafer S can be determined using a known algorithm in the image analysis of the imaging data. As an example, the central point Sc of the support wafer S is determined to be a point that is equal in distance from any point on the outer periphery Se of the support wafer S in the imaging data.

[0083] (First subprocess) In one embodiment, horizontal position adjustment (St10 in Figure 9) is performed by executing the first subprocess shown in Figure 10. In the first subprocess, the device wafer W is imaged using the upper imaging unit 151 to determine the center Wc of the device wafer W. Images of each element on the surface of the wafer are obtained in the various imaging data described herein. In the following description, the image of each element on the imaging data is simply described by the name and reference numeral of each element, and the description that it is "image of ~" is omitted. In addition, although an image of the center Wc of the device wafer W is not actually obtained in the imaging data, it is shown for convenience to explain the positional relationship with the virtual center Wv described later. Also, an image of the scribe line Ws may not actually be obtained in the imaging data.

[0084] During the movement process of the imaging center Mc, for example, the movement distance of the movement mechanisms of the upper imaging unit 151 and the lower imaging unit 161 can be stored, and the coordinate information of the start and end points of each movement, the coordinate difference, or the direction (vector) can be calculated and determined.

[0085] In the first subprocess, the upper imaging unit 151 is used to first image the surface Wa of the device wafer W, and the first imaging data ID1 is obtained as shown in Figure 11 (St101 in Figure 10).

[0086] Next, the virtual center Wv of the device wafer W is determined based on the first imaging data ID1 (St102 in Figure 10). The virtual center Wv can be determined using a known algorithm in the image analysis of the first imaging data ID1. As an example, the virtual center Wv is determined to be a point that is equal in distance from any point on the outer periphery We of the device wafer W in the first imaging data ID1. In this case, as shown in Figure 11, the center Wc of the device wafer W and the virtual center Wv do not necessarily coincide. This is thought to be because a part of the outer periphery We or notch Wn may be deformed or missing. Due to such deformation or missing parts, the image of the outer periphery We or notch Wn in the first imaging data ID1 may become blurry, as shown by the dashed line in Figure 11. If the center is determined from such a blurry image using a known algorithm, the center Wc and the virtual center Wv may not coincide.

[0087] Next, the imaging center Mc of the upper imaging unit 151 is moved from the virtual center Wv to a position P1' that corresponds to the coordinates of the first reference point P1 when the virtual center Wv is the origin (St103 in Figure 10). As described above, the coordinates of the first reference point P1, with the center Wc of the device wafer W as the first substrate as the origin, are known.

[0088] The movement control of the imaging center Mc of the upper imaging unit 151 in St103 will be explained using Figure 12. Figure 12 is an XY Cartesian coordinate system with the origin O being the center Wc in the plane of the device wafer W. For convenience, in Figure 12, the coordinates of the first reference point P1 in the XY Cartesian coordinate system are set to (a1, a2). In this case, St103 moves the imaging center Mc using the vector A(a1, a2) with the virtual center Wv as the starting point.

[0089] Next, the surface Wa of the device wafer W is imaged at the position P1' after the imaging center Mc of the upper imaging unit 151 has moved, and the second imaging data ID2 is obtained. The second imaging data ID2 includes the first reference point P1. Next, based on the second imaging data ID2, the coordinate difference between the first reference point P1 and the position P1' after the imaging center Mc has moved is measured and determined (St104 in Figure 10). As an example, this coordinate difference can be obtained as the vector B(b1,b2) shown in Figure 12 from the relative position of the first reference point P1 and the position P1' after the imaging center Mc has moved.

[0090] In one embodiment of St104, as shown in Figure 13, the imaging center Mc is moved from the position P1' after the movement of St103 to the center P1c of the first reference point P1. In Figure 14, the imaging center Mc and the center P1c of the first reference point P1 overlap in the imaging data (ID2') acquired after the movement. The center P1c of the first reference point P1 can be determined using a known algorithm in the image analysis of the second imaging data ID2. Furthermore, whether the imaging center Mc and the center P1c of the first reference point P1 overlap can be determined using a known algorithm in the image analysis of the imaging data (ID2') during the movement. In addition, the amount of movement (vector B) actually moved from position P1' to the center P1c of the first reference point P1 is recorded, and this amount of movement is determined as the coordinate difference between position P1' and the first reference point P1.

[0091] After St104, the same control as in St101 to St104 may be performed for the second reference point P2 to obtain other coordinate differences. The average of the multiple coordinate differences based on such multiple reference points may be defined as a representative value and used as the coordinate difference in St105 described later.

[0092] Next, based on the coordinate difference obtained in St104, the virtual center Wv is corrected to determine the center Wc of the device wafer W (St105 in Figure 10). As an example of correcting the virtual center Wv, in Figure 12, the endpoint of the vector B(b1,b2) starting from the virtual center Wv can be determined, and this endpoint can be determined as the center Wc of the device wafer W.

[0093] (Second subprocess) In another embodiment, horizontal position adjustment (St10 in Figure 9) involves executing a second subprocess shown in Figure 15. Figure 15 is a schematic flowchart of the configuration of the second subprocess.

[0094] In the second subprocess, first, the upper imaging unit 151 is used to image the surface Wa of the device wafer W, and the third imaging data ID3, as shown in Figure 16, is obtained (St201 in Figure 15). In this embodiment, the device wafer W has a first reference point P1, a second reference point P2, a central point Wc, and a notch Wn arranged on the same straight line. The straight line (P1P2) through which these points pass is shown by the dashed line in Figure 16. The first reference point P1 and the second reference point P2 are located at positions that are 180 degrees point-symmetric with respect to the central point Wc. In this embodiment, the device wafer W is placed on the lower chuck 140 with a rotational displacement of φ counterclockwise around the central point Wc of the device wafer W. Therefore, the image of each element on the third imaging data ID3 is obtained with a rotational displacement of φ counterclockwise. The amount of rotational displacement φ is the amount of deviation from the normal azimuth angle on the lower chuck 140. Such a normal azimuth angle is shown by the dashed line in Figure 16. In one embodiment, the placement position (azimuth angle) of the device wafer W in the lower chuck 140 is determined by referring to the notch Wn prior to placing the device wafer W in the lower chuck 140. As described above, the notch Wn may be obtained as an unclear image, in which case the azimuth angle of the device wafer W may deviate from the normal azimuth angle, as in this embodiment.

[0095] Next, the virtual center Wv of the device wafer W is determined based on the third imaging data ID3 (St202 in Figure 15). The determination of the virtual center Wv is the same as in St102 of the first subprocess. At this time, as shown in Figure 16, the center Wc of the device wafer W and the virtual center Wv do not necessarily coincide. That is, in addition to rotational misalignment, a misalignment occurs between the center Wc and the virtual center Wv for the same reasons as explained in the first subprocess.

[0096] Here, Figure 17 shows the positional relationship between the device wafer W and the imaging center Mc in each state of the second subprocess. Figures 17(a) to (h) show the time series when each state of the second subprocess is executed sequentially. In each state diagram of Figure 17, the components that are actually imaged (images formed on the imaging data) by the upper imaging unit 151 are shown with solid lines. However, the central part Wc is not actually imaged, but is shown as a black dot to facilitate understanding of the positional relationship. The dashed circle is a circle centered on the central part Wc, and is a virtual outer periphery We' assuming there is no deformation or defect in the outer periphery We of the device wafer W. In this embodiment, as a result of deformation or defect in the outer periphery We, the outer periphery We shown by the solid circle is imaged. As a result of determining the virtual central part Wv based on this outer periphery We in St202, the virtual central part Wv is shifted from the central part Wc. Also, the imaging center Mc in each state diagram is shown as a thick cross.

[0097] During the movement process of the imaging center Mc, for example, the movement distance of the movement mechanisms of the upper imaging unit 151 and the lower imaging unit 161 can be stored, and the coordinate information of the start and end points of each movement, the coordinate difference, or the direction (vector) can be calculated and determined.

[0098] Next, the imaging center Mc of the upper imaging unit 151 is moved from the virtual center Wv to the first position P1' which corresponds to the original coordinates of the first reference point P1 when the virtual center Wv is the origin (St203 in Figure 15, Figure 17(a)). The movement control of the imaging center Mc of the upper imaging unit 151 in St203 is the same as in St103 of the first subprocess.

[0099] Figures 18 and 19 show an XY Cartesian coordinate system in which the center Wc of the device wafer W is the origin O, and the straight line (P1P2) that occurs when the device wafer W is placed at a normal azimuthal angle coincides with the Y axis. In Figures 18 and 19, for convenience, the original coordinates of the first reference point P1 in the XY Cartesian coordinate system are set to (a1, a2). In this embodiment, the first reference point P1 and the second reference point P2 are in positions that are 180 degrees rotationally symmetric with respect to the center Wc, so the original coordinates of the second reference point P2 are (-a1, -a2). Here, "original coordinates of the first reference point P1" and "original coordinates of the second reference point P2" refer to the known coordinates of the first reference point P1 and the second reference point P2 with respect to the center Wc as the origin, assuming no rotational displacement of angle φ. In this case, St203 moves the imaging center Mc using vector A(a1,a2) with the virtual center Wv as the starting point.

[0100] Next, the surface Wa of the device wafer W is imaged at the first position P1' after the movement of the imaging center Mc of the upper imaging unit 151, and the fourth imaging data ID4 is obtained. The fourth imaging data ID4 includes the first reference point P1. Next, based on the fourth imaging data ID4, the first coordinate difference between the first reference point P1 and the first position P1' after the movement of the imaging center Mc is measured and determined (St204 in Figure 15, Figure 17(b)). In Figure 17, the first coordinate difference can be obtained as a vector C from the relative position of the first reference point P1 and the first position P1' after the movement of the imaging center Mc, as an example. The specific means for determining the first coordinate difference is the same as in St104 of the first subprocess. After determining the first coordinate difference, the imaging center Mc may overlap with the first reference point P1.

[0101] In St204, the position of the endpoint of vector C, which starts at the virtual center Wv, is further determined as the planned center Wv'. Like the virtual center Wv, the planned center Wv' is virtual coordinate information in the analysis of the imaging data and does not result in an image being obtained on the imaging data, but it is shown in the diagram for the sake of explanation.

[0102] Next, in Figure 19, the imaging center Mc of the upper imaging unit 151 is moved to the second position Q by a vector that starts at the first reference point P1 and points from the original coordinates of the first reference point P1 to the original coordinates of the second reference point P2 (St205 in Figure 15, Figure 17(c)). The movement control of the imaging center Mc of the upper imaging unit 151 in St205 is the same as in St103 of the first subprocess. In this embodiment, the vector from the first reference point P1 to the second reference point P2 is given as vector (-2A).

[0103] Next, the imaging center Mc of the upper imaging unit 151 is moved by a vector D that starts at the second position Q, is in the direction of the second reference point P2, and is perpendicular to the line P1Q (St206 in Figure 15, Figure 17(d)). The movement of the imaging center Mc stops at the third position R. The third position R is the point closest to the second reference point P2 on a line perpendicular to the line P1Q and passing through the second position Q. When moving the imaging center Mc starting from the second position Q, a step may be taken to confirm whether the second reference point P2 is on the positive or negative side of the X-axis when viewed from the second position Q. For example, this step can be confirmed based on the third imaging data ID3.

[0104] Next, the imaging center Mc of the upper imaging unit 151 is moved by a vector E that starts at the third position R, is in the direction of the second reference point P2, and is perpendicular to the straight line QR. (St207 in Figure 15, Figure 17(e)). The movement control of the imaging center Mc of the upper imaging unit 151 in St205 is the same as in St103 of the first subprocess.

[0105] Next, the rotational displacement φ is calculated (St208 in Figure 15). The rotational displacement φ can be determined geometrically from the coordinate information, coordinate differences, or vectors obtained in each of the above processes. As an example, let S be the point where the line QR and the line P1P2 intersect, as a virtual point in the calculation. The following equation (1) holds for the rotational displacement φ.

[0106]

number

[0107] In equation (1), P1Q, QR, and RS are the lengths of line segments P1Q, QR, and RS, respectively. Of these, point S is a hypothetical point, and its length cannot be measured from the imaging data. However, from the similarity of triangle P1QS and triangle P2RS, equation (2) is obtained, and the length of RS can be obtained from this equation. In equations (1) and (2), P1Q, QR, and P2R are known values ​​because their values ​​can be obtained as the amount of movement when the imaging center Mc is moved during each step.

[0108]

number

[0109] The value of the rotational displacement φ can be determined using the inverse trigonometric function (arctan) of tanφ obtained from equations (1) and (2).

[0110] Next, the rotational displacement of the device wafer W and the displacement of the center Wc are corrected based on the acquired value of the rotational displacement φ (St209 in Figure 15, Figures 17(f)~(h)). The correction of rotational displacement and the displacement of the center Wc can be performed simultaneously as follows, for example. First, the imaging center Mc is moved to the planned center Wv' (Figure 17(f)). Next, the wafer is rotated by an angle φ around the first reference point P1 in the direction in which the line P1P2 coincides with the line P1Q (Figure 17(g)). With this rotation, the center Wc should coincide with the corrected imaging center Mc, so the rotated imaging center Mc can be determined as the center Wc (Figure 17(h)).

[0111] According to the first or second subprocess described above, the horizontal position relative to the center Wc of the device wafer W, which has been determined in advance, can be adjusted by determining the center Wc of the support wafer S.

[0112] In one embodiment, the actual position of the notch Wn of the device wafer W is determined based on the center Wc of the device wafer W obtained by the first or second subprocess. In this embodiment, it is known that the notch Wn is located on the outer periphery We on a straight line passing through the first reference point P1, the second reference point P2, and the center Wc. Therefore, based on the first reference point P1, the second reference point P2, and the center Wc obtained by the first or second subprocess, the position of the outer periphery We on the straight line connecting them can be determined as the actual position of the notch Wn (Figure 17(h)).

[0113] The technical significance of the first or second subprocess will be explained below.

[0114] As described above, in this embodiment, the first substrate is a device wafer W on which the device layer D is formed, and the second substrate is a support wafer S on which the device layer D is not formed. The device wafer W on which the device layer D is formed may have deformation or defects in a part of the outer periphery We or notch Wn due to processes such as etching or trimming.

[0115] For a device wafer W in which a portion of the outer periphery We or notch Wn is deformed or missing, the virtual center Wv was determined in, for example, the first subprocesses St101 and St102. In known algorithms such as those described in St102, the virtual center Wv is determined as a position equal to the distance from any point on the outer periphery We. Therefore, if a portion of the outer periphery We or notch Wn used as a reference is deformed or missing, the determined virtual center Wv may deviate from the actual center Wc.

[0116] In contrast, according to the first or second subprocess of this embodiment, even if a part of the outer periphery We or notch Wn is deformed or missing, the actual center Wc can be determined from the virtual center Wv based on the coordinate difference.

[0117] Furthermore, if a portion of the outer periphery We or the notch Wn is deformed or missing, the device wafer W may be placed on the lower chuck 140 with a rotational misalignment. This is because, in the process of transporting the device wafer W to the lower chuck 140, the azimuth angle of the device wafer W may be determined by referring to the notch Wn. Even in such a case, according to the second subprocess of this embodiment, the rotational misalignment can be corrected and the actual center Wc can be determined from the virtual center Wv.

[0118] Furthermore, even if the notch Wn is deformed or missing, the first or second subprocess according to this embodiment makes it possible to determine the actual position of the notch Wn based on the center Wc of the device wafer W obtained.

[0119] In this embodiment, the case where the second substrate is a support wafer S has been described, but the embodiment is not limited to this. In one embodiment, when both the first substrate and the second substrate are device wafers W, the first subprocess or the second subprocess is performed on each of the first and second substrates to determine their central parts.

[0120] The first reference point P1 and the second reference point P2 may be located at a certain distance from the center Wc of the device wafer W, although this is not an exhaustive limitation. When the distance of the first reference point P1 and the second reference point P2 from the center Wc is large, the movement distance of the imaging center Mc becomes longer when St103, St203, or St205~St207 moves. In this case, the effects of rotational shift and center displacement may become larger. That is, the coordinate difference between the position P1' or P2' of the imaging center Mc after movement and the first reference point P1 or the second reference point P2 will largely reflect the effects of rotational shift and center displacement. By obtaining such a coordinate difference, the effects of rotational shift and center displacement can be accurately evaluated, and the center Wc can be determined more accurately.

[0121] Furthermore, the first reference point P1 and the second reference point P2 are alignment marks in this embodiment, but are not limited to these. In one embodiment, if the upper imaging unit 151 can image the scribe line Ws of the device wafer W, and the scribe line Ws can be observed in the imaging data for image analysis, then the first reference point P1 and the second reference point P2 can be points on the scribe line Ws whose coordinate positions with the central point Wc as the origin are known.

[0122] Returning to Figure 9, the lower chuck 140 is then moved vertically upward by the first lower chuck movement unit 164 to adjust the vertical position of the upper chuck 141 and the lower chuck 140, thereby adjusting the vertical position of the support wafer S held by the upper chuck 141 and the device wafer W held by the lower chuck 140 (St11 in Figure 9). Then, as shown in Figure 20(a), the support wafer S and the device wafer W are positioned facing each other in the desired position.

[0123] Next, a bonding process is performed between the support wafer S held by the upper chuck 141 and the device wafer W held by the lower chuck 140.

[0124] First, the control device 70 outputs a downward command to the push unit 180 (St12 in Figure 9), and the push unit 180 lowers the actuator unit 181 using the cylinder unit 182 based on this downward command. As the actuator unit 181 descends, as shown in Figure 20(b), the actuator unit 181 contacts the center of the back surface Sb of the support wafer S (St13 in Figure 9), and then the center Sc of the support wafer S is pressed and lowered further (St14 in Figure 9). Then, as shown in Figure 20(c), the push unit 180 brings the center of the support wafer S into contact with the center Wc of the device wafer W and presses them together (St15 in Figure 9). At this time, the operation of the first vacuum pump 177a is stopped to evacuate the support wafer S from the first suction port 175a in the first suction region 174a, while the second vacuum pump 177b is kept running to evacuate the second suction region 174b from the second suction port 175b. Furthermore, when the pushing part 180 presses the central part Sc of the support wafer S, the outer periphery of the support wafer S can be held by the upper chuck 141.

[0125] When the central part Sc of the support wafer S and the central part Wc of the device wafer W are brought into contact and pressed, bonding begins between the central parts Sc and Wc (thick lines in Figure 20(c)). That is, since the surface Sa of the support wafer S and the surface Wa of the device wafer W are modified at St1 and S6 respectively, van der Waals forces (intermolecular forces) are first generated between the surfaces Wa and Sa, and these surfaces Wa and Sa are bonded together. Furthermore, since the surface Sa of the support wafer S and the surface Wa of the device wafer W are hydrophilized at St2 and St7 respectively, the hydrophilic groups between the surfaces Wa and Sa form hydrogen bonds (intermolecular forces), and the surfaces Wa and Sa are firmly bonded together. Then, as shown in Figure 20(d), the bonding by van der Waals forces and hydrogen bonds between the surfaces Wa and Sa described above diffuses from the central parts Sc and Wc toward the outer periphery (St16 in Figure 9).

[0126] Subsequently, as shown in Figure 20(e), the second vacuum pump 177b is stopped while the pushing unit 180 is pressing the center Sc of the support wafer S and the center Wc of the device wafer W, thereby stopping the vacuum evacuation of the support wafer S from the second suction port 175b in the second suction region 174b. As a result, the outer periphery of the support wafer S falls onto the device wafer W. Then, as shown in Figure 20(f), the surface Sa of the support wafer S and the surface Wa of the device wafer W come into full contact, and the support wafer S and the device wafer W are joined together (St17 in Figure 9).

[0127] Subsequently, the actuator portion 181 of the pushing portion 180 is raised to the upper chuck 141. At the same time, the operation of the vacuum pumps 197a and 197b is stopped, the vacuuming of the device wafer W in the suction region 194 is stopped, and the suction holding of the device wafer W by the lower chuck 140 is stopped.

[0128] The polymerized wafer T, in which the support wafer S and the device wafer W are bonded, is transported to the transition device 51 by the wafer transport device 61, and then the desired cassette C of the cassette mounting plate 11 is transferred by the wafer transport device 22 of the loading / unloading station 2. T They are then transported to the facility. This completes the series of wafer W and S bonding processes.

[0129] <Inspection equipment> Next, the inspection apparatus 80 according to this embodiment will be described. Figure 21 is a schematic side view showing the configuration of the inspection apparatus 80 according to this embodiment. The inspection apparatus 80 can inspect the integrity of the bonding state of the polymerized wafer T bonded by the substrate processing system described above.

[0130] The inspection apparatus 80 has a chuck 300 that holds a polymerized wafer T on its upper surface. The chuck 300 holds the polymerized wafer T by suction. The chuck 300 is supported by a slider table 302 via an air bearing 301. A rotating mechanism 303 is provided on the lower side of the slider table 302. The rotating mechanism 303 incorporates, for example, a motor as a drive source. The chuck 300 is configured to rotate freely around the Z axis (vertical axis) via the air bearing 301 through the rotating mechanism 303. The slider table 302 is configured to move along a rail 305 that is provided on a base 306 and extends in the Y axis direction, by a moving mechanism 304 provided on its lower side. The drive source of the moving mechanism 304 is not particularly limited. In one embodiment, another slider table, moving mechanism, and rail are provided to further move the chuck 300 in the X axis direction.

[0131] An infrared imaging unit 310 is provided above the chuck 300. The infrared imaging unit 310 images the polymerized wafer T held by the chuck 300. In this case, the infrared imaging unit 310 is configured to image the outer peripheral portion Se and notch Sn of the support wafer S located on the upper side of the polymerized wafer T, as well as the first reference point P1 and second reference point P2 of the device wafer W located on the lower side. In one embodiment, the infrared imaging unit 310 includes a known IR camera.

[0132] <Method for inspecting the bonded state> Next, the method for inspecting the joint state according to this embodiment will be described with reference to Figure 22. Figure 22 is a schematic flowchart showing the configuration of the method for inspecting the joint state according to this embodiment. The method for inspecting the joint state according to this embodiment can be performed in the inspection device 80 described above. It can also be performed in any external inspection device having a similar configuration to the inspection device 80.

[0133] In St301, the infrared imaging unit 310 is used to image the polymerized wafer T from the surface Sa side of the support wafer S, and infrared imaging data IRD is acquired (St301 in Figure 22).

[0134] Next, the central point Sc of the support wafer S is determined. The central point Sc of the support wafer S can be determined using a known algorithm in the image analysis of infrared imaging data IRD. As an example, the central point Sc of the support wafer S is determined to be a point that is equal in distance from any point on the outer periphery Se of the support wafer S in the infrared imaging data IRD.

[0135] Next, a first line L1 connecting the center Sc of the support wafer S and the notch Sn, and a second line L2 connecting the first reference point P1 and the second reference point P2 of the device wafer W are drawn, and the angle ψ between them is determined. In the example in Figure 23, the first line L1 and the second line L2 overlap, and the angle ψ between them is approximately 0 degrees.

[0136] Figure 24 shows the infrared imaging data (IRD) of a polymerized wafer T, which is a reference example formed by joining a support wafer S and a device wafer W in a rotationally misaligned state. In the polymerized wafer T shown in Figure 24, the first straight line L1 and the second straight line L2 do not overlap, and the angle ψ they form is greater than 0 degrees.

[0137] Next, the angle ψ formed by the first line L1 and the second line L2 is compared with a desired threshold, and it is determined whether the angle ψ is within the range of the threshold. In one embodiment, the polymerized wafer T shown in Figure 23 has an angle ψ formed by the first line L1 and the second line L2 that is approximately 0 degrees, and is determined to be within the threshold range, thus passing the test. In contrast, the polymerized wafer T shown in Figure 24 has a large angle ψ formed by the first line L1 and the second line L2, and is determined to be outside the threshold range, thus failing the test.

[0138] In one embodiment, the polymerized wafer T that is determined to be unacceptable is placed in a separate cassette C as an abnormal wafer, from the polymerized wafer T that is determined to be normal. T They will be confined there.

[0139] In this embodiment, the threshold range is set to a few degrees around 0 degrees, but it is not limited to this. In one embodiment, if the angle ψ formed by the first line L1 and the second line L2 intersects within a range of a few degrees around 90 degrees, the threshold can be set to a range of a few degrees around 90 degrees. In addition, the threshold range can be set to a few degrees before and after a desired angle.

[0140] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. For example, the constituent elements of the embodiments described above can be combined in any way. Such any combination will naturally yield the functions and effects of each constituent element in the combination, as well as other functions and effects that will be apparent to those skilled in the art from the description herein.

[0141] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that are obvious to those skilled in the art from the description herein, in addition to or instead of the effects described herein.

[0142] Furthermore, the following configuration examples also fall within the technical scope of this disclosure. (1) A substrate processing system, It comprises a bonding device for joining substrates together, and a control device, The bonding device is A first holding part that holds the first substrate, A second holding portion is provided below or above the first holding portion and holds the second substrate, A contact member that brings the center of the first substrate and the center of the second substrate into contact, At least an imaging unit for imaging the first substrate, The system includes a moving mechanism for moving the first holding unit, the second holding unit, and the imaging unit relative to each other, The first substrate includes at least one reference point whose coordinates are known, with the center of the first substrate as the origin. The control device is (a) A step of imaging the first substrate and determining the virtual center of the first substrate, (b) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (c) A step of imaging the first substrate at the position moved in step (b) and obtaining the coordinate difference between the imaging center and the reference point, (d) A step of correcting the virtual center to determine the center of the first substrate, (e) A step of bringing the center of the first substrate determined in step (d) into contact with the center of the second substrate, A substrate processing system that performs control including the following. (2) The control device, in step (d), corrects the virtual center based on the coordinate difference obtained in step (c) to determine the center of the first substrate, as described in (1). (3) The first substrate is provided with two or more reference points, The control device is (f) After performing step (c) above, a step of further moving the imaging center to another reference point to obtain the amount of rotational displacement of the first substrate. The substrate processing system described in (1) above, which performs control including the following. (4) The control device, in step (d), corrects the virtual center by rotation based on the amount of rotational deviation obtained in step (f) to determine the center of the first substrate, as described in (3). (5) The substrate processing system according to any one of (1) to (4) above, wherein at least the first substrate is a substrate on which a pattern has been formed, and the reference point is an alignment mark in the pattern formation. (6) The imaging unit is configured to be able to image the second substrate, The moving mechanism is configured to allow the second holding unit and the imaging unit to move relative to each other. The second substrate includes at least one reference point whose coordinates are known, with the center of the second substrate as the origin. The control device is (g) A step of imaging the second substrate and determining the virtual center of the second substrate, (h) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (i) A step of imaging the second substrate at the position moved in step (h) above and obtaining the coordinate difference between the imaging center and the reference point, (j) A step of correcting the virtual center to determine the center of the second substrate, A substrate processing system according to any one of (1) to (5) above, which performs control including the following: (7) The substrate processing system according to (6) above, wherein the first substrate and the second substrate are substrates on which a pattern has been formed, and the reference point is an alignment mark in the pattern formation. (8) An inspection device for inspecting a polymerized substrate in which the first substrate and the second substrate are joined together, The second substrate has a notch on its outer edge, The inspection apparatus includes a third holding section for holding the polymerization substrate, An inspection imaging unit for imaging the aforementioned polymerized substrate, The device comprises a moving mechanism for moving the third holding unit and the inspection imaging unit relative to each other, The control device is (p) After the execution of step (e) above, the polymerized substrate is transported to the inspection apparatus, and the second substrate is imaged from the second substrate side of the polymerized substrate to determine the center of the polymerized substrate, (q) A step of obtaining the angle formed by a first straight line connecting the center of the polymerization substrate and the notch of the second substrate, and a second straight line connecting the center of the polymerization substrate and the reference point of the first substrate, (r) A step of comparing the angle with a threshold and determining whether the angle is within the range of the threshold, A substrate processing system according to any one of (1) to (7) above, which performs control including the following. (9) The control device is (s) If the angle is outside the range of the threshold, the bonding state of the polymerized substrate is determined to be unacceptable and processed as an abnormal substrate. The substrate processing system described in (8) above, which performs control including the following: (10) A joining device, A first holding part that holds the first substrate, A second holding portion is provided below or above the first holding portion and holds the second substrate, A contact member that brings the center of the first substrate and the center of the second substrate into contact, At least an imaging unit for imaging the first substrate, A moving mechanism for moving the first holding part, the second holding part, and the imaging part relative to each other, It comprises a control unit and, The first substrate includes at least one reference point whose coordinates are known, with the center of the first substrate as the origin. The control unit, (a) A step of imaging the first substrate and determining the virtual center of the first substrate, (b) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (c) A step of imaging the first substrate at the position moved in step (b) and obtaining the coordinate difference between the imaging center and the reference point, (d) A step of correcting the virtual center to determine the center of the first substrate, (e) A step of bringing the center of the first substrate determined in step (d) into contact with the center of the second substrate, A bonding device that performs control including the following. (11) A method for joining a first substrate and a second substrate using a bonding device, The bonding device is A first holding portion that holds the first substrate, A second holding portion is provided below or above the first holding portion and holds the second substrate, A contact member that brings the center of the first substrate and the center of the second substrate into contact, At least an imaging unit for imaging the first substrate, The system includes a moving mechanism for moving the first holding unit, the second holding unit, and the imaging unit relative to each other, The first substrate includes at least one reference point whose coordinates are known, with the center of the first substrate as the origin. The aforementioned joining method is (a) A step of imaging the first substrate and determining the virtual center of the first substrate, (b) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (c) A step of imaging the first substrate at the position moved in step (b) and obtaining the coordinate difference between the imaging center and the reference point, (d) A step of correcting the virtual center to determine the center of the first substrate, (e) A step of bringing the center of the first substrate determined in step (d) into contact with the center of the second substrate, A joining method that includes this. [Explanation of Symbols]

[0143] 1. Substrate Processing System 41 Bonding equipment 70 Control device 140 Bottom zipper 141 Top zipper 151 Upper imaging section 153 Rotating part 154 Linear Scale 161 Lower imaging section 164 First lower chuck movement section 166 Second lower chuck movement section 181 Actuator section W device wafer Wc center S Support wafer Sc center T Polymerized wafer P1 1st reference point Mc imaging center

Claims

1. A substrate processing system, It comprises a bonding device for joining substrates together, and a control device, The bonding device is A first holding part that holds the first substrate, A second holding portion is provided below or above the first holding portion and holds the second substrate, A contact member that brings the center of the first substrate and the center of the second substrate into contact, At least an imaging unit for imaging the first substrate, The system includes a moving mechanism for moving the first holding unit, the second holding unit, and the imaging unit relative to each other, The first substrate includes at least one reference point whose coordinates are known, with the center of the first substrate as the origin. The control device is (a) A step of imaging the first substrate and determining the virtual center of the first substrate, (b) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (c) A step of imaging the first substrate at the position moved in step (b) above, and obtaining the coordinate difference between the imaging center and the reference point, (d) A step of correcting the virtual center to determine the center of the first substrate, (e) A step of bringing the center of the first substrate determined in step (d) into contact with the center of the second substrate, A substrate processing system that performs control including the following.

2. The substrate processing system according to claim 1, wherein the control device, in step (d), corrects the virtual center based on the coordinate difference obtained in step (c) to determine the center of the first substrate.

3. The first substrate is provided with two or more of the aforementioned reference points, The control device is (f) After performing step (c), a step of further moving the imaging center to another reference point to obtain the amount of rotational displacement of the first substrate. A substrate processing system according to claim 1, which performs control including the following:

4. The substrate processing system according to claim 3, wherein the control device, in step (d), corrects the virtual center by rotation based on the amount of rotational deviation obtained in step (f) to determine the center of the first substrate.

5. A substrate processing system according to any one of claims 1 to 4, wherein at least the first substrate is a substrate on which a pattern has been formed, and the reference point is an alignment mark in the pattern formation.

6. The imaging unit is configured to be able to image the second substrate, The moving mechanism is configured to allow the second holding unit and the imaging unit to move relative to each other. The second substrate includes at least one reference point whose coordinates are known, with the center of the second substrate as the origin. The control device is (g) A step of imaging the second substrate to determine the virtual center of the second substrate, (h) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (i) A step of imaging the second substrate at the position moved in step (h) above and obtaining the coordinate difference between the imaging center and the reference point, (j) A step of correcting the virtual center to determine the center of the second substrate, A substrate processing system according to any one of claims 1 to 4, which performs control including the following:

7. The substrate processing system according to claim 6, wherein the first substrate and the second substrate are substrates on which a pattern has been formed, and the reference point is an alignment mark in the pattern formation.

8. The system includes an inspection device for inspecting a polymerized substrate in which the first substrate and the second substrate are joined, The second substrate has a notch on its outer edge, The inspection apparatus includes a third holding section for holding the polymerization substrate, An inspection imaging unit for imaging the aforementioned polymerized substrate, The device comprises a moving mechanism for moving the third holding unit and the inspection imaging unit relative to each other, The control device is (p) After the execution of step (e), the polymerized substrate is transported to the inspection apparatus, and the second substrate is imaged from the second substrate side of the polymerized substrate to determine the center of the polymerized substrate, (q) A step of obtaining the angle formed by a first straight line connecting the center of the polymerization substrate and the notch of the second substrate, and a second straight line connecting the center of the polymerization substrate and the reference point of the first substrate, (r) A step of comparing the angle with a threshold and determining whether the angle is within the range of the threshold, A substrate processing system according to any one of claims 1 to 3, which performs control including the following:

9. The control device is (s) If the angle is outside the range of the threshold, the bonding state of the polymerized substrate is determined to be unacceptable and processed as an abnormal substrate. A substrate processing system according to claim 8, which performs control including the following:

10. A joining device, A first holding part that holds the first substrate, A second holding portion is provided below or above the first holding portion and holds the second substrate, A contact member that brings the center of the first substrate and the center of the second substrate into contact, At least an imaging unit for imaging the first substrate, A moving mechanism for moving the first holding part, the second holding part, and the imaging part relative to each other, It comprises a control unit and, The first substrate includes at least one reference point whose coordinates are known, with the center of the first substrate as the origin. The control unit, (a) A step of imaging the first substrate and determining the virtual center of the first substrate, (b) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (c) A step of imaging the first substrate at the position moved in step (b) above, and obtaining the coordinate difference between the imaging center and the reference point, (d) A step of correcting the virtual center to determine the center of the first substrate, (e) A step of bringing the center of the first substrate determined in step (d) into contact with the center of the second substrate, A bonding device that performs control including the following.

11. A method for joining a first substrate and a second substrate using a bonding device, The bonding device is A first holding part that holds the first substrate, A second holding portion is provided below or above the first holding portion and holds the second substrate, A contact member that brings the center of the first substrate and the center of the second substrate into contact, At least an imaging unit for imaging the first substrate, The system includes a moving mechanism for moving the first holding unit, the second holding unit, and the imaging unit relative to each other, The first substrate includes at least one reference point whose coordinates are known, with the center of the first substrate as the origin. The aforementioned joining method is (a) A step of imaging the first substrate and determining the virtual center of the first substrate, (b) A step of moving the imaging center of the imaging unit from the virtual center to a position corresponding to the coordinates of the reference point with the virtual center as the origin, (c) A step of imaging the first substrate at the position moved in step (b) above, and obtaining the coordinate difference between the imaging center and the reference point, (d) A step of correcting the virtual center to determine the center of the first substrate, (e) A step of bringing the center of the first substrate determined in step (d) into contact with the center of the second substrate, A joining method that includes this.

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