Bonding system and inspection method for overlapping substrates

Abstract

The bonding system (1) disclosed in the present invention comprises a bonding device (41), an inspection device (80) and a control unit (70). The bonding device forms an overlapping substrate (T) by bonding a first substrate (W1) and a second substrate (W2). The inspection device inspects the overlapping substrate. The control unit controls the inspection device. In addition, the control unit comprises a measurement control unit (71a), a comparison unit (71c) and a re-measurement control unit (71e). The measurement control unit causes the inspection device to measure the overlapping substrate with a first number of measurement points. The comparison unit compares the inspection result (72a) including the offset between the first substrate and the second substrate in the overlapping substrate derived from the measurement result with a reference (72b). Based on the comparison result of the comparison unit, the re-measurement control unit causes the inspection device to re-measure the overlapping substrate with a second number of measurement points greater than the first number of measurement points.

Description

Technical Field

[0001] The present disclosure relates to a bonding system and a method for inspecting overlapped substrates. Background Art

[0002] There is known a bonding system including a bonding apparatus for bonding substrates such as semiconductor wafers to form a superposed substrate and an inspection apparatus for inspecting the superposed substrate formed by the bonding apparatus (see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-187716 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure provides a technology capable of ensuring the measurement accuracy of an inspection device and improving productivity.

[0008] Solutions for solving problems

[0009] A bonding system of one embodiment of the present disclosure includes a bonding device, an inspection device, and a control unit. The bonding device forms an overlapping substrate by bonding a first substrate and a second substrate. The inspection device inspects the overlapping substrate. The control unit controls the inspection device. In addition, the control unit includes a measurement control unit, a comparison unit, and a re-measurement control unit. The measurement control unit causes the inspection device to measure the overlapping substrate with a first number of measurement points. The comparison unit compares the inspection result including the offset amount of the first substrate and the second substrate in the overlapping substrate derived from the measurement result with a reference. Based on the comparison result of the comparison unit, the re-measurement control unit causes the inspection device to re-measure the overlapping substrate with a second number of measurement points that is greater than the first number of measurement points.

[0010] Effects of the Invention

[0011] According to the present disclosure, it is possible to ensure the measurement accuracy of the inspection device and improve the productivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram showing the structure of the joining system involved in the embodiment.

[0013] Figure 2 It is a schematic diagram showing a state before bonding of a first substrate and a second substrate according to the embodiment.

[0014] Figure 3 It is a schematic diagram showing the structure of a bonding device according to an embodiment.

[0015] Figure 4 It is a schematic diagram showing the structure of the inspection device involved in the embodiment.

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

[0017] Figure 6 This is a diagram showing an example of an imaging method of a measurement mark.

[0018] Figure 7 This is a diagram showing an example of a measurement mark.

[0019] Figure 8 It is a block diagram showing the structure of the control device involved in the embodiment.

[0020] Fig. 9 This is a diagram showing an example of measurement points set in the measurement process.

[0021] Fig.10 This is a diagram for explaining an example of reference information.

[0022] Fig.11 This is a diagram showing an example of determination processing performed by the determination unit.

[0023] Fig.12 This is a diagram showing an example of measurement points set in the remeasurement process.

[0024] Fig.13 This is a flowchart showing an example of a process procedure until a superimposed substrate is formed by a bonding apparatus, among processes executed by the bonding system.

[0025] Fig.14 This is a flowchart showing an example of the processing procedure of the inspection process.

[0026] Fig.15 It is a diagram showing a first modified example of measurement points set in the measurement process.

[0027] Fig.16 It is a diagram showing a second modification example of the measurement points set in the measurement process.

[0028] Fig.17 It is a diagram showing a modified example of the measurement points set in the remeasurement process. DETAILED DESCRIPTION

[0029] Hereinafter, the method for implementing the joint system and the inspection method for overlapping substrates disclosed in the present invention (hereinafter referred to as "embodiment") will be described in detail with reference to the accompanying drawings. In addition, the joint system and the inspection method for overlapping substrates disclosed in the present invention are not limited by this embodiment. In addition, each embodiment can be appropriately combined within the scope of the processing content not contradictory. In addition, in each of the following embodiments, the same mark is marked on the same part, and repeated description is omitted.

[0030] In the embodiments described below, terms such as "fixed", "orthogonal", "perpendicular", or "parallel" are sometimes used, but these terms do not necessarily mean "fixed", "orthogonal", "perpendicular", or "parallel" in a strict sense. That is, the above terms are set to allow for deviations in manufacturing accuracy, setting accuracy, etc.

[0031] In addition, in the drawings referred to below, in order to facilitate the understanding of the description, an orthogonal coordinate system is sometimes shown in which the X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other and the positive direction of the Z-axis is set as the vertical upward direction. In addition, the rotation direction with the vertical axis as the rotation center is sometimes referred to as the θ direction.

[0032] <Structure of the joint system>

[0033] First, refer to Figure 1 and Figure 2 The structure of the joining system according to the embodiment will be described. Figure 1 Schematic diagram showing the structure of the joining system according to the embodiment. Figure 2 It is a schematic diagram showing a state before bonding of a first substrate and a second substrate according to the embodiment.

[0034] Figure 1 The bonding system 1 shown in the figure forms a superimposed substrate T (see FIG. 1 ) by bonding a first substrate W1 and a second substrate W2. Figure 2 ).

[0035] The first substrate W1 and the second substrate W2 are substrates on which a plurality of circuits are formed, for example, on semiconductor substrates such as silicon wafers and compound semiconductor wafers. The first substrate W1 and the second substrate W2 have substantially the same diameter. In addition, one of the first substrate W1 and the second substrate W2 may be a substrate on which no circuit is formed, for example.

[0036] Below, as Figure 2As shown, the plate surface of the first substrate W1 on the side bonded to the second substrate W2 is recorded as "bonding surface W1j", and the plate surface on the side opposite to the bonding surface W1j is recorded as "non-bonding surface W1n". In addition, the plate surface of the second substrate W2 on the side bonded to the first substrate W1 is recorded as "bonding surface W2j", and the plate surface on the side opposite to the bonding surface W2j is recorded as "non-bonding surface W2n".

[0037] like Figure 1 As shown, the bonding system 1 includes a loading and unloading station 2, a processing station 3, and an inspection station 4. The loading and unloading station 2 is arranged on the negative side of the X-axis of the processing station 3 and is connected to the processing station 3 as a whole. In addition, the inspection station 4 is arranged on the positive side of the X-axis of the processing station 3 and is connected to the processing station 3 as a whole.

[0038] The loading and unloading station 2 includes a loading platform 10 and a conveying area 20. The loading platform 10 includes a plurality of loading plates 11. Boxes C1 to C4 for accommodating a plurality of (e.g., 25) substrates in a horizontal state are placed on each loading plate 11. Box C1 can accommodate a plurality of first substrates W1, box C2 can accommodate a plurality of second substrates W2, and box C3 can accommodate a plurality of overlapping substrates T. Box C4 is, for example, a box for recovering defective substrates. In addition, the number of boxes C1 to C4 placed on the loading plate 11 is not limited to the number shown in the figure.

[0039] The conveying area 20 is arranged adjacent to the X-axis positive direction side of the mounting table 10. The conveying area 20 is provided with a conveying path 21 extending in the Y-axis direction and a conveying device 22 that can move along the conveying path 21. The conveying device 22 can move not only in the Y-axis direction but also in the X-axis direction and can rotate around the Z-axis. The conveying device 22 conveys the first substrate W1, the second substrate W2, and the overlapped substrate T between the cassettes C1 to C4 mounted on the mounting plate 11 and the third processing block G3 of the processing station 3 described later.

[0040] For example, three processing blocks G1, G2, and G3 are provided in the processing station 3. The first processing block G1 is arranged on the back side of the processing station 3 ( Figure 1 In addition, the second processing block G2 is arranged on the front side of the processing station 3 ( Figure 1 The third processing block G3 is arranged on the side of the processing station 3 close to the loading and unloading station 2 ( Figure 1 negative side of the X-axis).

[0041] The first processing block G1 is provided with a surface modification device 30 for modifying the bonding surfaces W1j and W2j of the first substrate W1 and the second substrate W2. The surface modification device 30 cuts the bonds of SiO2 in the bonding surfaces W1j and W2j of the first substrate W1 and the second substrate W2 and converts them into single-bonded SiO, thereby modifying the bonding surfaces W1j and W2j to be easily hydrophilicized later.

[0042] Specifically, in the surface modification device 30, oxygen or nitrogen as a processing gas is excited to plasma, for example, in a reduced pressure atmosphere, thereby ionizing it. Then, by irradiating the bonding surfaces W1j and W2j of the first substrate W1 and the second substrate W2 with the oxygen ions or nitrogen ions, the bonding surfaces W1j and W2j are modified by plasma treatment.

[0043] In addition, a surface hydrophilization device 40 is disposed in the first processing block G1. The surface hydrophilization device 40 hydrophilizes the bonding surfaces W1j and W2j of the first substrate W1 and the second substrate W2 with pure water, for example, and cleans the bonding surfaces W1j and W2j. Specifically, the surface hydrophilization device 40 supplies pure water to the first substrate W1 or the second substrate W2 while rotating the first substrate W1 or the second substrate W2 held by the rotating chuck. As a result, the pure water supplied to the first substrate W1 or the second substrate W2 spreads on the bonding surfaces W1j and W2j of the first substrate W1 or the second substrate W2 to hydrophilize the bonding surfaces W1j and W2j.

[0044] Here, the case where the surface modifying device 30 and the surface hydrophilizing device 40 are arranged side by side in the lateral direction is illustrated, but the surface hydrophilizing device 40 may be stacked on the surface modifying device 30 .

[0045] The second processing block G2 is provided with a bonding device 41. The bonding device 41 bonds the hydrophilized first substrate W1 and the second substrate W2 by intermolecular force. The structure of the bonding device 41 will be described later.

[0046] A conveying area 60 is formed in an area surrounded by the first processing block G1, the second processing block G2, and the third processing block G3. A conveying device 61 is disposed in the conveying area 60. The conveying device 61 has, for example, a conveying arm that is movable in the vertical direction and the horizontal direction and around the vertical axis. The conveying device 61 moves in the conveying area 60 to convey the first substrate W1, the second substrate W2, and the overlapped substrate T to the prescribed devices in the first processing block G1, the second processing block G2, and the third processing block G3 adjacent to the conveying area 60.

[0047] The inspection station 4 is provided with an inspection device 80 . The inspection device 80 inspects the superimposed substrates T formed by the bonding device 41 .

[0048] Furthermore, the joining system 1 includes a control device 70. The control device 70 controls the operation of the joining system 1. The configuration of the control device 70 will be described later.

[0049] <Structure of bonding device>

[0050] Next, refer to Figure 3 The structure of the bonding device 41 will be described. Figure 3 It is a schematic diagram showing the structure of a bonding device 41 according to the embodiment.

[0051] like Figure 3 As shown, the engaging device 41 includes a first holding portion 140 , a second holding portion 141 , and a striker 190 .

[0052] The first holding portion 140 includes a main body 170. The main body 170 is supported by a supporting member 180. A through hole 176 is formed in the supporting member 180 and the main body 170, penetrating the supporting member 180 and the main body 170 in a vertical direction. The position of the through hole 176 corresponds to the center of the first substrate W1 held by the first holding portion 140. The pressing pin 191 of the striker 190 passes through the through hole 176.

[0053] The striker 190 is disposed on the upper surface of the support member 180 and includes a pressing pin 191 , an actuator unit 192 , and a linear motion mechanism 193 . The pressing pin 191 is a cylindrical member extending in the vertical direction and is supported by the actuator unit 192 .

[0054] The actuator part 192 generates a fixed pressure in a fixed direction (here, vertically downward) by, for example, air supplied from an electric pneumatic regulator (not shown). The actuator part 192 can control the pressing load applied to the center of the first substrate W1 by contacting the center of the first substrate W1 through the air supplied from the electric pneumatic regulator. In addition, the front end of the actuator part 192 can be freely raised and lowered in the vertical direction by passing through the through hole 176 through the air from the electric pneumatic regulator.

[0055] The actuator unit 192 is supported by a linear motion mechanism 193. The linear motion mechanism 193 moves the actuator unit 192 in the vertical direction by a drive unit including, for example, a motor.

[0056] The striker 190 controls the movement of the actuator 192 through the direct-acting mechanism 193, and controls the pressing load of the pressing pin 191 on the first substrate W1 through the actuator 192. Thus, the striker 190 presses the center of the first substrate W1 sucked and held by the first holding portion 140 to make it contact with the second substrate W2.

[0057] A plurality of pins 171 are provided on the lower surface of the main body 170 to contact the upper surface (non-bonding surface W1n) of the first substrate W1. The pins 171 have a diameter of, for example, 0.1 mm to 1 mm and a height of several tens to several hundreds of μm. The pins 171 are evenly arranged at intervals of, for example, 2 mm.

[0058] The first holding part 140 has a plurality of adsorption parts for adsorbing the first substrate W1 in a part of the area where the plurality of pins 171 are provided. Specifically, a plurality of outer adsorption parts 301 and a plurality of inner adsorption parts 302 for adsorbing the first substrate W1 by vacuuming are provided on the lower surface of the main body 170 in the first holding part 140. The plurality of outer adsorption parts 301 and the plurality of inner adsorption parts 302 have an arc-shaped adsorption area when viewed from above. The plurality of outer adsorption parts 301 and the plurality of inner adsorption parts 302 have the same height as the pins 171.

[0059] The plurality of outer suction parts 301 are disposed on the outer periphery of the main body 170. The plurality of outer suction parts 301 are connected to a suction device (not shown) such as a vacuum pump, and suction the outer periphery of the first substrate W1 by vacuuming.

[0060] The inner suction parts 302 are arranged circumferentially at positions radially inward of the main body 170 relative to the outer suction parts 301. The inner suction parts 302 are connected to a suction device (not shown) such as a vacuum pump to suction the area between the outer periphery and the center of the first substrate W1 by vacuuming.

[0061] The second holding portion 141 is described. The second holding portion 141 has a main body 200 having a diameter that is the same as the diameter of the second substrate W2 or a diameter that is larger than the diameter of the second substrate W2. Here, the second holding portion 141 having a diameter that is larger than the diameter of the second substrate W2 is shown. The upper surface of the main body 200 is a facing surface that faces the lower surface (non-bonding surface W2n) of the second substrate W2.

[0062] A plurality of pins 201 are provided on the upper surface of the main body 200 so as to contact the lower surface (non-joining surface Wn2) of the second substrate W2. The diameter of the plurality of pins 201 is, for example, 0.1 mm to 1 mm, and the height is several tens of μm to several hundreds of μm. The plurality of pins 201 are evenly arranged at intervals of, for example, 2 mm.

[0063] In addition, a lower rib 202 is provided in an annular shape on the upper surface of the main body 200 and outside the plurality of pins 201. The lower rib 202 is formed in an annular shape and supports the outer peripheral portion of the second substrate W2 over the entire circumference.

[0064] The main body 200 has a plurality of lower suction ports 203. The plurality of lower suction ports 203 are provided in the adsorption region surrounded by the lower rib 202. The plurality of lower suction ports 203 are connected to a suction device (not shown) such as a vacuum pump via a suction pipe (not shown).

[0065] The second holding unit 141 evacuates the suction region surrounded by the lower ribs 202 from the plurality of lower suction ports 203 , thereby reducing the pressure in the suction region. As a result, the second substrate W2 placed in the suction region is suction-held by the second holding unit 141 .

[0066] Since the lower ribs 202 support the outer periphery of the lower surface of the second substrate W2 all around, the second substrate W2 can be properly vacuumed up to the outer periphery of the second substrate W2. Thus, the entire surface of the second substrate W2 can be adsorbed and held. In addition, since the lower surface of the second substrate W2 is supported by a plurality of pins 201, the second substrate W2 can be easily peeled off from the second holding portion 141 when the vacuum of the second substrate W2 is released.

[0067] Although not shown in the figure, the bonding device 41 is Figure 3 The first holding part 140, the second holding part 141, etc. shown in the figure have a conveying part, a reversing mechanism, a position adjustment mechanism, etc. The conveying part temporarily carries the first substrate W1, the second substrate W2, and the overlapping substrate T. The position adjustment mechanism adjusts the horizontal direction of the first substrate W1 and the second substrate W2. The reversing mechanism reverses the front and back surfaces of the first substrate W1.

[0068] <Structure of inspection device>

[0069] Next, refer to Figure 4 and Figure 5 The structure of the inspection device will be described. Figure 4 Schematic diagram showing the structure of the inspection device involved in the embodiment. Figure 5 Schematic diagram showing the structure of a holding portion of an inspection device according to an embodiment. Figure 4 This is a schematic diagram of the inspection device viewed from the side. Figure 5 This is a schematic diagram of the holding portion of the inspection device as viewed from above.

[0070] like Figure 4 As shown, the inspection device 80 includes a holding unit 400 , an imaging unit 500 , and an illumination unit 600 .

[0071] like Figure 4 and Figure 5 As shown, the holding unit 400 horizontally holds the superimposed substrates T. The holding unit 400 includes a main body 410 and a plurality of support members 420 .

[0072] The main body 410 is a flat plate-shaped member having an opening 411 having a diameter larger than that of the superimposed substrate T. The main body 410 is connected to a moving mechanism 440 and can be moved in horizontal directions (X-axis direction and Y-axis direction) and rotated around a vertical axis.

[0073] The plurality of support members 420 are provided on the main body 410 so as to extend toward the center of the opening 411. The outer periphery of the superimposed substrate T is supported by the front end portions of the plurality of support members 420. The front end portions of the plurality of support members 420 are connected to a suction device 480 such as a vacuum pump via a suction pipe 460, and the outer periphery of the lower surface of the superimposed substrate T is sucked by vacuuming.

[0074] The imaging unit 500 is disposed above the holding unit 400. The imaging unit 500 includes a camera lens 501 and an imaging element 502 such as a CCD image sensor or a CMOS image sensor. The imaging unit 500 is connected to a lifting mechanism 510 and is lifted and lowered by the lifting mechanism 510, thereby being able to adjust the distance between the imaging unit 500 and the upper surface of the superimposed substrate T (i.e., the upper surface of the first substrate W1).

[0075] The lighting unit 600 is disposed below the holding unit 400. Specifically, the lighting unit 600 is disposed at a position facing the camera unit 500 across the overlapping substrate T held by the holding unit 400. The lighting unit 600 irradiates light from below the overlapping substrate T held by the holding unit 400 toward the vertically upward direction. For example, the lighting unit 600 irradiates near-infrared light of 1000 to 1200 nm. The lighting unit 600 is connected to a lifting mechanism 610, and is lifted and lowered by the lifting mechanism 610, thereby being able to adjust the distance between the lighting unit 600 and the lower surface of the overlapping substrate T (i.e., the lower surface of the second substrate W2).

[0076] In addition, the inspection device 80 may include a plurality of imaging units with different magnifications. For example, the inspection device 80 may include an imaging unit for macro imaging and an imaging unit for micro imaging. In this case, the inspection device 80 may include an illumination unit at a position facing the imaging unit for macro imaging and at a position facing the imaging unit for micro imaging.

[0077] The inspection device 80 is configured as described above, and images the measurement marks formed on the first substrate W1 and the second substrate W2 . Figure 6 : is a diagram showing an example of a method for photographing a measurement mark. Figure 7 This is a diagram showing an example of a measurement mark.

[0078] like Figure 6As shown, the inspection device 80 irradiates light from the lighting unit 600 toward the vertical upper direction. The light irradiated from the lighting unit 600 reaches the imaging element 502 of the imaging unit 500 via the second substrate W2 and the first substrate W1. That is, the imaging unit 500 photographs the overlapping substrate T by the transmitted light that has passed through the overlapping substrate T. Specifically, measurement marks M1 and M2 are formed on the first substrate W1 and the second substrate W2, respectively, and the imaging unit 500 photographs the measurement marks M1 and M2. The image data photographed by the imaging unit 500 is output to the control device 70.

[0079] like Figure 7 As shown, the image data includes images of the measurement mark M1 formed on the first substrate W1 and the measurement mark M2 formed on the second substrate W2. The control device 70 analyzes the image data to obtain measurement results such as the coordinates of the center of gravity points P1 and P2 of the measurement marks M1 and M2, the offset of the center of gravity points P1 and P2, and the like, and checks the bonding state of the overlapping substrates T based on the obtained measurement results.

[0080] <Structure of control device>

[0081] Next, refer to Figure 8 The structure of the control device 70 will be described. Figure 8 is a block diagram showing the structure of the control device 70 involved in the embodiment. Figure 8 9 shows a configuration related to the inspection device 80 among the configurations included in the control device 70 .

[0082] like Figure 8 As shown, the control device 70 includes a control unit 71 and a storage unit 72. The control unit 71 includes a measurement control unit 71a, a reference generation unit 71b, a comparison unit 71c, a determination unit 71d, and a re-measurement control unit 71e. The storage unit 72 stores test result information 72a and reference information 72b.

[0083] The control device 70 includes, for example, a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), an input / output port, and various circuits.

[0084] The CPU of the computer functions as the measurement control unit 71a, the reference generation unit 71b, the comparison unit 71c, the determination unit 71d, and the re-measurement control unit 71e of the control unit 71 by, for example, reading and executing the program stored in the ROM. In addition, at least one or all of the measurement control unit 71a, the reference generation unit 71b, the comparison unit 71c, the determination unit 71d, and the re-measurement control unit 71e may be configured by hardware such as an ASIC (Application Specific Integrated Circuit), a GPU (Graphics Processing Unit), or an FPGA (Field Programmable Gate Array).

[0085] The storage unit 72 corresponds to, for example, a RAM or a HDD. The RAM or the HDD can store the inspection result information 72a and the reference information 72b. The control device 70 can acquire the above-mentioned programs and various information via other computers or portable recording media connected via a wired or wireless network.

[0086] (About the measurement control unit)

[0087] The measurement control unit 71 a sets a first number of measurement points on the superimposed substrate T, and causes the inspection device 80 to measure the superimposed substrate T at each of the measurement points. Fig. 9 This is a diagram showing an example of measurement points set in the measurement process.

[0088] like Fig. 9 As shown, in the embodiment, the measurement control unit 71a sets four measurement points on the outer periphery of the superimposed substrate T and one measurement point on the center, setting a total of five measurement points R on the superimposed substrate T. That is, in the present embodiment, the number of first measurement points is five.

[0089] The four measuring points R provided at the periphery are arranged at equal intervals, that is, at intervals of 90 degrees. In other words, the five measuring points R including the measuring point R provided at the center are set to be rotationally symmetrical (four-fold symmetrical in this case) with respect to the superimposed substrate T. Thus, for example, compared to the case where a plurality of measuring points R are concentrated at specific locations on the periphery, it is possible to appropriately detect bonding failures caused by the tilt of the first holding portion 140 or the second holding portion 141 of the bonding device 41.

[0090] The measurement control unit 71a acquires image data as a measurement result from the inspection device 80. Moreover, the measurement control unit 71a derives the inspection result including the offset between the first substrate W1 and the second substrate W2 in the overlapping substrate T based on the acquired image data. Specifically, the measurement control unit 71a calculates the X coordinate (x1) and Y coordinate (y1) of the measurement mark M1, and the X coordinate (x2) and Y coordinate (y2) of the measurement mark M2 at each measurement point R by analyzing the image data. In addition, the measurement control unit 71a calculates the offset (Δx) of the X coordinate of the measurement marks M1 and M2 and the offset (Δy) of the Y coordinate of the measurement marks M1 and M2. Moreover, the measurement control unit 71a substitutes the calculation results (x1, y1, x2, y2, Δx, Δy) corresponding to the number of the first measurement points (five in this case) into the pre-prepared calculation model.

[0091] The calculation model, for example, decomposes the offset of the first substrate W1 relative to the second substrate W2 into components such as an offset in the X-axis direction (X displacement), an offset in the Y-axis direction (Y displacement), an offset in the rotation direction around the vertical axis (rotation), and an offset due to expansion and contraction (scaling). The measurement control unit 71a uses the calculation model to obtain the inspection results of the above components and stores the obtained inspection results in the storage unit 72.

[0092] (About the reference generation department)

[0093] The reference generating section 71b generates reference information 72b. The reference information 72b is information including a reference value for each component of the offset of the first substrate W1 and the second substrate W2.

[0094] The reference generating unit 71b generates reference information 72b of the superimposed substrate T to be inspected this time (hereinafter referred to as the inspection target substrate T) based on the inspection result of the inspected superimposed substrate T (hereinafter referred to as the inspected substrate T).

[0095] Fig.10 72b is a diagram for explaining an example of reference information 72b. Fig.10 As shown, the cassettes C4a and C4b have, for example, 25 slots S1a to S25a, S1b to S25b, and each of the slots S1a to S25a, S1b to S25b can accommodate a superimposed substrate T. For example, in the cassette C4a, the slots S1a to S25a accommodate superimposed substrates T1a to T25a, respectively.

[0096] The bonding system 1 sets a plurality of (here, 25) superimposed substrates T accommodated in the cassette C4 as one substrate group, and performs a series of processes including bonding processing by the bonding device 41 and inspection processing by the inspection device 80 on the substrate group basis.

[0097] The overlapped substrates T that have completed a series of processes (i.e., inspected substrates T) are sequentially stored starting from the topmost slot in the cassette C4. For example, the overlapped substrate T1a that is processed first among the overlapped substrates T1a to T25a belonging to one substrate group is stored in the topmost slot S1a of the cassette C4a, and the overlapped substrate T2a that is processed next is stored in the next slot located below the slot S1a, i.e., the slot S2a.

[0098] The reference generating unit 71b generates reference information 72b of the inspection target substrate based on the inspection results of one or more inspected substrates that are in the same substrate group as the inspection target substrate T. That is, for example, a predetermined overlapping substrate T4b accommodated in the slot S4b of the cassette C4b is set as the inspection target substrate. In this case, the reference generating unit 71b generates reference information 72b of the inspection target substrate T4b based on the inspection results of at least one inspected substrate among the inspected substrates T1b to T3b accommodated in the slots S1b to S3b of the same cassette C4b.

[0099] For example, the reference generating unit 71b may generate the inspection result of the first processed inspected overlapping substrate T1b among the plurality of inspected substrates T1b to T3b of the same substrate group as the reference information 72b of the inspection target substrate T4b. In this case, the plurality of overlapping substrates T belonging to the same substrate group other than the first processed overlapping substrate T1b can share the reference information 72b, so that the processing load of the reference generating unit can be reduced.

[0100] In this case, the reference generating unit 71b may generate the reference information 72b of the overlapped substrate T1b based on the inspection result of the substrate group processed before the overlapped substrate T1b belongs to, for example. For example, the reference generating unit 71b may generate the inspection result of the first inspected substrate T1a processed among the plurality of inspected substrates T1a to T25a stored in the cassette C4a as the reference information 72b. Alternatively, the average value of the inspection results of the plurality of inspected substrates T1a to T25a stored in the cassette C4a may be generated as the reference information 72b of the overlapped substrate T1b.

[0101] Furthermore, the reference generating unit 71 b may generate, as the reference information 72 b of the substrate T to be inspected, an average value of the inspection results of two or more inspected substrates T among a plurality of inspected substrates T of the same substrate group.

[0102] For example, the reference generating unit 71b may generate the average value of the inspection results of all the inspected overlapping substrates T1b to T3b in the same substrate group as the reference information 72b of the inspection target substrate T4b. In addition, the reference generating unit 71b may generate the average value of the inspection results of two or more inspected substrates T (e.g., inspected substrates T2b and T3b) including the inspected substrate T3b processed immediately before the inspection target substrate T4b as the reference information 72b of the inspection target substrate T4b. In this way, by using the average value of the inspection results of a plurality of overlapping substrates T belonging to the same substrate group as the reference information 72b, the reliability of the reference information 72b can be improved.

[0103] In addition, the reference generating unit 71b is not limited to generating the reference information 72b based on the same substrate group, but may also generate the reference information 72b based on the inspection results of the inspected substrates T belonging to different substrate groups. For example, the reference generating unit 71b may generate the inspection results of the inspected substrates T of the substrate group different from the substrate group of the inspection target substrate T and having the same processing order as the inspection target substrate T in the substrate group unit as the reference information 72b of the inspection target substrate T. That is, the reference generating unit 71b may generate the inspection results of the inspected substrates T4a stored in the slot S4a of the cassette C4a different from the cassette C4b storing the inspection target substrates T4b as the reference information 72b of the inspection target substrates T4b.

[0104] The overlapped substrates T accommodated in the same slot of different cassettes C4 are likely to be processed along the same path in the bonding system 1. That is, if a plurality of bonding devices 41 and inspection devices 80 are provided in the bonding system 1, the overlapped substrates T accommodated in the same slot of different cassettes C4 are likely to be transported to the same bonding device 41 and inspection device 80. Therefore, by using the inspection results of the overlapped substrates T accommodated in the same slot as the reference information 72b, the reliability of the reference information 72b can be improved.

[0105] In this way, the reference generating unit 71b generates the reference information 72b of the inspection target substrate T based on the inspection result of the inspected substrate T inspected before the inspection target substrate T which is the current inspection target.

[0106] (About the Comparison Department)

[0107] The comparison unit 71c compares the inspection result information 72a stored in the storage unit 72 with the reference information 72b. Specifically, the comparison unit 71c calculates the difference between each component (X displacement, Y displacement, rotation, scaling) of the offset of the first substrate W1 relative to the second substrate W2 included in the inspection result and the reference value.

[0108] (About the Judgment Department)

[0109] The determination unit 71d determines whether to re-measure the inspection target substrate T or whether the inspection target substrate T is defectively bonded, based on the comparison result of the comparison unit 71c. Fig.11 To illustrate this point. Fig.11 is a diagram showing an example of the determination process performed by the determination unit 71d. Fig.11 , a graph is shown in which the horizontal axis represents the processing order in one substrate group and the vertical axis represents the comparison result of the comparison unit 71c, that is, the difference between the inspection result and the reference value. In addition, as an example, the comparison result regarding the X displacement component is shown here.

[0110] like Fig.11 As shown, for example, the difference between the inspection result of the X displacement in the mth superimposed substrate T and the reference value exceeds the first threshold, which is in the range of -50 nm to +50 nm. In this case, the determination unit 71d determines that the bonding between the first substrate W1 and the second substrate W2 is defective.

[0111] In this case, the control unit 71 may generate poor joining information that associates information indicating poor joining of the mth superimposed substrate T with the identification number of the mth superimposed substrate T, and store the information in the storage unit 72. In addition, the control unit 71 may transmit the generated poor joining information to an external device via a network.

[0112] In addition, it is assumed that the difference between the inspection result of the X displacement in the n-th superimposed substrate T and the reference value exceeds the second threshold value, which is in the range of -30 nm to +30 nm, and does not exceed the first threshold value, which is in the range of -50 nm to +50 nm. In this case, the determination unit 71d determines to perform re-measurement of the inspection target substrate T.

[0113] (About the re-measurement control unit)

[0114] The remeasurement control unit 71e causes the inspection device 80 to remeasure the inspection target substrate T according to the determination result of the determination unit 71d. Specifically, the remeasurement control unit 71e causes the inspection device 80 to remeasure the inspection target substrate T using a second number of measurement points greater than the first number of measurement points set in the measurement process performed by the measurement control unit 71a.

[0115] Fig.12 FIG. 1 is a diagram showing an example of measurement points set in the re-measurement process. Fig.12 As shown, the re-measurement control unit 71e sets eight measurement points at the outer periphery of the superimposed substrate T and one measurement point at the center, setting a total of nine measurement points R on the superimposed substrate T. That is, in this embodiment, the number of second measurement points is nine.

[0116] In the re-measurement process, similarly to the measurement process, the measurement marks M1 and M2 are photographed at each measurement point R. The re-measurement control unit 71e calculates the X coordinate (x1) and Y coordinate (y1) of the measurement mark M1, and the X coordinate (x2) and Y coordinate (y2) of the measurement mark M2 based on the image data obtained by the re-measurement process. In addition, the re-measurement control unit 71e calculates the offset (Δx) of the X coordinate of the measurement marks M1 and M2 and the offset (Δy) of the Y coordinate of the measurement marks M1 and M2. Moreover, the re-measurement control unit 71e substitutes the calculation results (x1, y1, x2, y2, Δx, Δy) corresponding to the number of second measurement points (here, nine) into the pre-prepared calculation model. Thus, the re-measurement control unit 71e obtains the inspection results for each component of the offset of the first substrate W1 relative to the second substrate W2, and stores the obtained inspection results in the storage unit 72 as the inspection result information 72a.

[0117] As described above, the inspection device 80 captures the measurement marks M1 and M2 using the transmitted light that has passed through the overlapped substrate T. However, since it is difficult to obtain a sufficient amount of light using the transmitted light, the exposure time of the imaging unit 500 tends to be set long. Therefore, the more the number of measurement points, the longer the time required for the measurement process for one overlapped substrate T, which may lead to a decrease in productivity. On the other hand, it is conceivable to suppress the decrease in productivity by reducing the number of measurement points, but the fewer the number of measurement points, the lower the accuracy of the measurement process.

[0118] Therefore, in the joint system 1 according to the embodiment, when the measurement process is performed with a relatively small number of measurement points and the inspection result based on the measurement process deviates from the reference information 72b, re-measurement is performed with an increased number of measurement points compared to the measurement process. Thus, the measurement accuracy of the inspection device 80 can be ensured and productivity can be improved.

[0119] <Specific Operations of the Joint System>

[0120] Next, the specific operation of the joint system 1 will be described. Fig.13 The processing procedure until the superimposed substrates T are formed by the bonding device 41 will be described. Fig.13 1 is a flowchart showing an example of a process procedure until the superimposed substrates T are formed by the bonding apparatus 41 , among processes executed by the bonding system 1 . Fig.13 The various processes shown are executed based on the control of the control device 70 .

[0121] First, a cassette C1 containing a plurality of first substrates W1, a cassette C2 containing a plurality of second substrates W2, and an empty cassette C3 are placed on a predetermined loading plate 11 of the loading / unloading station 2. Then, the first substrate W1 in the cassette C1 is taken out by the conveying device 22 and conveyed to the conveyor device disposed in the third processing block G3.

[0122] Next, the first substrate W1 is transported to the surface modification device 30 of the first processing block G1 by the transport device 61. In the surface modification device 30, oxygen gas as a processing gas is excited to plasma under a predetermined reduced pressure atmosphere, thereby ionizing it. The oxygen ions are irradiated to the bonding surface of the first substrate W1 to perform plasma treatment on the bonding surface. Thus, the bonding surface of the first substrate W1 is modified (step S101).

[0123] Next, the first substrate W1 is transported to the surface hydrophilization device 40 of the first processing block G1 by the transport device 61. In the surface hydrophilization device 40, pure water is supplied to the first substrate W1 while rotating the first substrate W1 held by the rotating chuck. Thus, the bonding surface of the first substrate W1 is hydrophilized. In addition, the bonding surface of the first substrate W1 is cleaned by the pure water (step S102).

[0124] Next, the first substrate W1 is transported to the bonding device 41 of the second processing block G2 by the transport device 61. The first substrate W1 transported to the bonding device 41 is transported to the position adjustment mechanism via the conveyor, and the horizontal orientation is adjusted by the position adjustment mechanism (step S103).

[0125] After that, the first substrate W1 is transferred from the position adjustment mechanism to the reversing mechanism, and the front and back surfaces of the first substrate W1 are reversed by the reversing mechanism (step S104 ). Specifically, the bonding surface W1j of the first substrate W1 is directed downward.

[0126] Thereafter, the first substrate W1 is delivered from the reversing mechanism to the first holding unit 140. The first substrate W1 is suction-held by the first holding unit 101 with the cutout facing a predetermined direction (step S105).

[0127] The processing of the second substrate W2 is repeated with the processing of steps S101 to S105 performed on the first substrate W1. First, the second substrate W2 in the cassette C2 is taken out by the transport device 22 and transported to the conveyor device arranged in the third processing block G3.

[0128] Next, the second substrate W2 is transported to the surface modification device 30 by the transport device 61, and the bonding surface W2j of the second substrate W2 is modified (step S106). After that, the second substrate W2 is transported to the surface hydrophilization device 40 by the transport device 61, and the bonding surface W2j of the second substrate W2 is hydrophilized and cleaned (step S107).

[0129] Then, the second substrate W2 is transported to the bonding device 41 by the transport device 61. The second substrate W2 transported to the bonding device 41 is transported to the position adjustment mechanism by the conveyor. Then, the horizontal direction of the second substrate W2 is adjusted by the position adjustment mechanism (step S108).

[0130] Thereafter, the second substrate W2 is conveyed to the second holding section 141 , and is suction-held by the second holding section 141 with the cutout facing a predetermined direction (step S109 ).

[0131] Next, the positions of the first substrate W1 held by the first holding portion 140 and the second substrate W2 held by the second holding portion 141 in the horizontal direction are adjusted (step S110 ).

[0132] Next, the vertical positions of the first substrate W1 held by the first holding portion 140 and the second substrate W2 held by the second holding portion 141 are adjusted (step S111). Specifically, the second holding portion 141 is moved vertically upward by the first moving portion 160, so that the second substrate W2 is brought closer to the first substrate W1.

[0133] Next, after the suction and holding of the first substrate W1 by the plurality of inner suction portions 302 is released (step S112 ), the pressing pin 191 of the striker 190 is lowered to press the center portion of the first substrate W1 downward (step S113 ).

[0134] When the center of the first substrate W1 contacts the center of the second substrate W2 and the center of the first substrate W1 and the center of the second substrate W2 are pressed with a specified force by the impact pin 190, the pressed center of the first substrate W1 and the center of the second substrate W2 begin to bond. That is, since the bonding surface W1j of the first substrate W1 and the bonding surface W2j of the second substrate W2 are modified in steps S101 and S109, respectively, van der Waals force (intermolecular force) is first generated between the bonding surfaces W1j and W2j, so that the bonding surfaces W1j and W2j are bonded. In addition, since the bonding surface W1j of the first substrate W1 and the bonding surface W2j of the second substrate W2 are hydrophilized in steps S102 and S110, respectively, the hydrophilic groups between the bonding surfaces W1j and W2j are hydrogen bonded, and the bonding surfaces W1j and W2j are firmly bonded to each other. In this way, a bonding area is formed.

[0135] Afterwards, a bonding wave is generated between the first substrate W1 and the second substrate W2, in which the bonding area gradually expands from the center of the first substrate W1 and the second substrate W2 toward the periphery. Afterwards, the adsorption and holding of the first substrate W1 by the plurality of outer adsorption parts 301 are released (step S114). As a result, the periphery of the first substrate W1 adsorbed and held by the outer adsorption parts 301 falls down. As a result, the bonding surface W1j of the first substrate W1 and the bonding surface W2j of the second substrate W2 are in full contact with each other, forming an overlapping substrate T.

[0136] Then, the pressing pins 191 are raised to the first holding portion 140 to release the suction holding of the second substrate W2 by the second holding portion 141. Then, the superimposed substrate T is carried out of the bonding device 41 by the transport device 61. In this way, a series of bonding processes are completed.

[0137] Next, refer to Fig.14 The following describes the process of the inspection process performed by the inspection device 80. Fig.14 This is a flowchart showing an example of the processing procedure of the inspection process.

[0138] like Fig.14 As shown, in the inspection device 80, first, a process of carrying in the inspection target substrate T is performed (step S201). Specifically, the conveying device 61 (see Figure 1 ) The inspection target substrate T is transported to the inside of the holding portion 400, and the inspection device 80 receives the inspection target substrate T from the transport device 61 using an elevator (not shown). Next, the inspection target substrate T is placed on the plurality of support members 420 by the elevator movement of the inspection device 80. Then, the suction device 480 vacuums the inspection target substrate T via the suction pipe 460, thereby adsorbing and holding the inspection target substrate T on the holding portion 400.

[0139] Next, in the inspection device 80, a θ alignment process is performed (step S202). The θ alignment process is a process for adjusting the position of the inspection object substrate T in the rotation direction. Specifically, the inspection device 80 uses the camera unit 500 to capture multiple reference points (for example, a reference point located at the center of the inspection object substrate T and a reference point located at an adjacent position thereof) existing on the inspection object substrate T. Moreover, the inspection device 80 calculates the rotation angle of the inspection object substrate T based on the obtained image, and uses the moving mechanism 440 to rotate the inspection object substrate T in such a manner that the rotation angle becomes 0 degrees. In addition, for example, when a pattern is formed on the first substrate W1 or the second substrate W2 by an exposure process, the reference point is formed together with the pattern on the first substrate W1 or the second substrate W2 in each exposure. That is, the inspection device 80 rotates the inspection object substrate T in such a manner that the arrangement direction of the pattern of each exposure of the inspection object substrate T is always in the same direction.

[0140] Next, the inspection device 80 performs a measurement process (step S203). Specifically, the inspection device 80 uses the moving mechanism 440 to horizontally move the holding unit 400, thereby positioning the imaging unit 500 and the lighting unit 600 on the vertical line of the first measurement point R. After that, the inspection device 80 uses the imaging unit 500 and the lighting unit 600 to capture images of the measurement marks M1 and M2 located at the first measurement point R, while performing focusing of the imaging unit 500 and position correction of the holding unit 400.

[0141] The inspection device 80 performs the same processing for the remaining measurement points R. That is, the inspection device 80 repeats the above processing a number of times corresponding to the first number of measurement points (here, a number of times corresponding to five points). Furthermore, the control unit 71 calculates each component of the offset amount of the first substrate W1 relative to the second substrate W2, namely, X displacement, Y displacement, rotation, and scaling, based on the obtained number of measurement results corresponding to the first number of measurement points (here, five).

[0142] Next, the control unit 71 determines whether the comparison result, i.e., the difference (absolute value) between each component of the offset of the first substrate W1 relative to the second substrate W2 and the reference value of each component included in the reference information 72b exceeds the first threshold value (absolute value) (step S204). In the case where the comparison result (absolute value) of any of the above components exceeds the first threshold value (absolute value), the control unit 71 determines that the comparison result (absolute value) exceeds the first threshold value (absolute value). In the case where it is determined that the comparison result (absolute value) exceeds the first threshold value (absolute value) (step S204, "yes"), the control unit 71 determines that the bonding state of the inspection object substrate T is poor bonding (step S205).

[0143] On the other hand, in step S204, when the comparison result (absolute value) does not exceed the first threshold value (absolute value) (step S204, "No"), the control unit 71 determines whether the comparison result (absolute value) exceeds the second threshold value (absolute value) (step S206). In this process, when it is determined that the comparison result (absolute value) exceeds the second threshold value (absolute value) (step S206, "Yes"), the control unit 71 causes the inspection device 80 to perform a re-measurement process on the inspection object substrate T. The re-measurement process is performed with a second number of measurement points (here, nine) that is larger than the number of measurement points in the measurement process in step S203, that is, the number of first measurement points. Therefore, the accuracy of the measurement process can be improved compared to the measurement process. In other words, an inspection result closer to the true value can be obtained compared to the measurement process.

[0144] In step S206 , when the comparison result (absolute value) does not exceed the second threshold value (absolute value) (step S206 , No), the control unit 71 determines that the bonding state of the inspection target substrate T is normal (step S208 ).

[0145] When the processing of steps S205, S207, and S208 is completed, the inspection device 80 performs a process of unloading the inspection target substrate T (step S209). The unloading process is performed in the reverse order of the loading process of step S201.

[0146] Alternatively, after completing the re-measurement process of step S207, the control unit 71 may transfer the process to step S204. In this case, if it is determined again in step S206 that the comparison result (absolute value) exceeds the second threshold value (absolute value), the control unit 71 may perform re-measurement with a further increased number of measurement points.

[0147] (Modification of measurement point)

[0148] Next, refer to Figure 15 to Figure 17 A modified example of setting the measurement point on the inspection target substrate T will be described. Fig.15 and Fig.16 A modification example of the measurement points set in the measurement process will be described. Fig.15 It is a diagram showing a first modified example of measurement points set in the measurement process. Fig.16 It is a diagram showing a second modification example of the measurement points set in the measurement process.

[0149] like Fig.15As shown, for example, the measurement points R of the first number of measurement points in the measurement process can be set only at the periphery of the inspection target substrate T. The bonding wave is a bonding area that gradually expands from the center of the first substrate W1 and the second substrate W2 toward the periphery, so the offset between the first substrate W1 and the second substrate W2 is larger at the periphery than at the center of the inspection target substrate T. Therefore, by setting the measurement points R at the periphery of the inspection target substrate T, the offset between the first substrate W1 and the second substrate W2 can be more appropriately found than when the measurement points R are set at the center of the inspection target substrate T.

[0150] In addition, if Fig.15 As shown, the first substrate W1 and the second substrate W2 constituting the inspection object substrate T are single crystal silicon wafers whose crystal direction in the direction perpendicular to the surface is

[100] . The cutout portion N of the first substrate W1 and the second substrate W2 is formed at the outer edge of the

[011] crystal direction of the first substrate W1 and the second substrate W2. In addition, the Miller index is usually expressed as negative by marking "-" (bar) on the number, but in this specification, it is expressed by marking a negative sign before the number.

[0151] When the center of the first substrate W1 is pressed down by the striker 190 in the bonding device 41 to make it contact with the center of the second substrate W2, the center of the first substrate W1 and the center of the second substrate W2 are bonded by intermolecular force, thereby forming a bonding area in the center of the two substrates. After that, a bonding wave is generated in which the bonding area gradually expands from the center of the two substrates toward the periphery, so that the bonding surfaces W1j and W2j of the first substrate W1 and the second substrate W2 are bonded in their entirety.

[0152] When the first substrate W1 is held by a holding portion that holds the entire circumference of the outer edge of the first substrate W1 and the above-mentioned bonding process is performed, the bonding area is expanded concentrically. However, the first substrate W1 and the second substrate W2, which are single crystal silicon wafers, have different physical properties such as Young's modulus and Poisson's ratio in the 90-degree direction and the 45-degree direction, so the degree of deformation in the 90-degree direction and the 45-degree direction is different. Here, the 90-degree direction is a 90-degree periodic direction based on the direction from the center of the first substrate W1 toward the [0-11] crystal direction parallel to the surface of the first substrate W1 ( Fig.15 The 45-degree direction is a 90-degree periodic direction based on the direction from the center of the first substrate W1 toward the

[010] crystal direction parallel to the surface of the first substrate W1 ( Fig.15 45 degrees, 135 degrees, 225 degrees, 315 degrees as shown).

[0153] The values ​​of Young's modulus, Poisson's ratio, and shear modulus of a single crystal silicon wafer change in a 90-degree cycle. Specifically, the Young's modulus of a single crystal silicon wafer is highest in the 90-degree direction and lowest in the 45-degree direction. In addition, the Poisson's ratio and shear modulus are highest in the 45-degree direction and lowest in the 90-degree direction.

[0154] Thus, the expansion and contraction of the first substrate W1 and the second substrate W2 after the bonding process are different in the 45 degree direction and the 90 degree direction. That is, the offset between the first substrate W1 and the second substrate W2 in the inspection target substrate T is different in the 45 degree direction and the 90 degree direction.

[0155] Therefore, if Fig.15 As shown, the measurement control unit 71a can set four measurement points R in the 45 degree direction (45 degree, 135 degree, 225 degree, 315 degree direction) and also set four measurement points R in the 90 degree direction (0 degree, 90 degree, 180 degree, 270 degree direction). Thus, the displacement between the first substrate W1 and the second substrate W2 can be appropriately found.

[0156] Here, the case where the measurement point R is set in all directions of the 45-degree direction (directions of 45 degrees, 135 degrees, 225 degrees, and 315 degrees) and the 90-degree direction (directions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees) is exemplified. However, the present invention is not limited to this, and the measurement control unit 71a may set the measurement point R in at least one angular direction of the 45-degree direction (directions of 45 degrees, 135 degrees, 225 degrees, and 315 degrees) and at least one angular direction of the 90-degree direction (directions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees).

[0157] In addition, if Fig.16 As shown in FIG. 1 , the measurement control unit 71a can set the measurement point R in a direction between the 45-degree direction and the 90-degree direction. Fig.16 In the example shown, four measurement points R are set at four locations, namely, between 0 and 45 degrees, between 90 and 135 degrees, between 180 and 225 degrees, and between 270 and 315 degrees. In this way, the rotational symmetry can be maintained, the number of first measurement points can be suppressed, and the displacement between the first substrate W1 and the second substrate W2 can be appropriately found.

[0158] Next, refer to Fig.17 A modification example of the measurement point set in the remeasurement process will be described. Fig.17 It is a diagram showing a modified example of the measurement points set in the remeasurement process.

[0159] like Fig.17As shown in FIG. 1 , the re-measurement control unit 71 e may further set a measurement point R between the measurement point R set at the center of the inspection target substrate T and the measurement point R set at the outer periphery. Fig.17 In the example shown, measurement points R are set between the measurement points R at the periphery in the 0 degree direction and the measurement points R at the center, and between the measurement points R at the periphery in the 90 degree direction and the measurement points R at the center. In addition, measurement points R are set between the measurement points R at the periphery in the 180 degree direction and the measurement points R at the center, and between the measurement points R at the periphery in the 270 degree direction and the measurement points R at the center. Fig.17 In the example shown, a total of thirteen measurement points are set.

[0160] In this way, by increasing the number of second measurement points, the accuracy of the re-measurement process can be further improved, and an inspection result closer to the true value can be obtained.

[0161] As described above, the bonding system involved in the embodiment (e.g., bonding system 1) includes a bonding device (e.g., bonding device 41), an inspection device (e.g., inspection device 80), and a control unit (e.g., control device 70). The bonding device forms an overlapping substrate (e.g., overlapping substrate T) by bonding a first substrate (e.g., first substrate W1) and a second substrate (e.g., second substrate W2). The inspection device inspects the overlapping substrate. The control unit controls the inspection device. In addition, the control unit includes a measurement control unit (e.g., measurement control unit 71a), a comparison unit (e.g., comparison unit 71c), and a re-measurement control unit (e.g., re-measurement control unit 71e). The measurement control unit causes the inspection device to measure the overlapping substrate with a first number of measurement points (e.g., five). The comparison unit compares the inspection result (e.g., inspection result information 72a) including the offset between the first substrate and the second substrate in the overlapping substrate derived from the measurement result with a reference (e.g., reference information 72b). The remeasurement control unit causes the inspection device to remeasure the overlapped substrate using a second number of measurement points (eg, nine) that is greater than the first number of measurement points based on the comparison result of the comparison unit.

[0162] Therefore, according to the bonding system involved in the embodiment, it is possible to ensure the measurement accuracy of the inspection device and improve the productivity.

[0163] The control unit may further include a determination unit (e.g., determination unit 71d) that determines that the first substrate and the second substrate are poorly bonded when the difference between the inspection result and the reference exceeds a first threshold value (e.g., a range of greater than -50nm and less than +50nm). In this case, when the difference between the inspection result and the reference exceeds a second threshold value (e.g., a range of greater than -30nm and less than +30nm) that is smaller than the first threshold value and does not exceed the first threshold value, the re-measurement control unit may cause the inspection device to re-measure the overlapped substrates.

[0164] It is considered that the accuracy of the measurement performed with the first number of measurement points is insufficient when the difference between the inspection result and the reference exceeds the second range but does not exceed the first range. Therefore, when the difference between the inspection result and the reference exceeds the second range but does not exceed the first range, re-measurement is performed, thereby improving the measurement accuracy. On the other hand, when the difference between the inspection result and the reference exceeds the first range, in other words, when the difference between the inspection result and the reference becomes larger as it exceeds the range of the measurement error of the inspection device, it can be determined as a poor joint without even re-measurement.

[0165] The control unit may further include a reference generating unit (e.g., reference generating unit 71b) that generates a reference of the inspection target overlap substrate based on the inspection result of an inspected overlap substrate (e.g., inspected substrate T) that was inspected before the inspection target overlap substrate (e.g., inspection target substrate T) that is the inspection target this time.

[0166] For example, the reference generating unit can generate a reference of the inspection target overlapped substrate based on the inspection results of one or more inspected overlapped substrates of the same substrate group. Thus, by using the inspection results of inspected overlapped substrates belonging to the same substrate group, an appropriate reference of the inspection target overlapped substrate can be generated.

[0167] The reference generating unit can generate the inspection result of the first inspected overlapping substrate among the plurality of inspected overlapping substrates of the same substrate group as a reference for the inspected overlapping substrate. In this case, the reference can be shared among the plurality of overlapping substrates other than the first inspected overlapping substrate belonging to the same substrate group, thereby suppressing the processing load for generating the reference.

[0168] The reference generating unit may generate an average value of the inspection results of two or more inspected overlapped substrates among a plurality of inspected overlapped substrates of the same substrate group as a reference for the inspected overlapped substrate, thereby improving the reliability of the reference.

[0169] The reference generating unit can generate an inspection result of an inspected overlapping substrate that is in a different substrate group from the inspection target overlapping substrate and has the same processing order as the inspection target overlapping substrate in the substrate group unit as a reference for the inspection target overlapping substrate. By using the inspection result of the overlapping substrate with the same processing order as a reference, the reliability of the reference can be improved.

[0170] The measurement control unit may set the measurement points (e.g., measurement points R) of the first measurement point number only at the periphery of the overlapping substrates. In addition, the re-measurement control unit may set the measurement points totaling the second measurement point number at the periphery and the center of the overlapping substrates. The bonding wave is a bonding area that gradually expands from the center of the first substrate and the second substrate toward the periphery, so with respect to the offset between the first substrate and the second substrate, the offset at the periphery is larger than the offset at the center of the inspection object substrate. Therefore, by setting the measurement points at the periphery of the inspection object overlapping substrate, the offset between the first substrate and the second substrate can be more appropriately found compared to the case where the measurement points are set at the center of the inspection object overlapping substrate.

[0171] The first substrate and the second substrate can be single crystal silicon wafers whose surface crystallization direction is

[100] . In this case, when the direction from the center of the overlapping substrate toward the [0-11] crystallization direction parallel to the surface of the overlapping substrate is set to 0 degrees, the measurement control unit can set measurement points for at least one of the four first peripheral parts arranged at 90 degrees intervals based on the 45-degree direction and at least one of the four second peripheral parts arranged at 90 degrees intervals based on the 90-degree direction. When the first substrate and the second substrate, which are single crystal silicon wafers whose surface crystallization direction is

[100] , are bonded, the offset between the first substrate and the second substrate is different in the 45-degree direction and the 90-degree direction. Therefore, by setting measurement points in the 45-degree direction and the 90-degree direction, the offset between the first substrate W1 and the second substrate W2 can be properly found.

[0172] In addition, in the above-mentioned embodiment, a bonding device is cited as an example in which the center of the first substrate is pressed by a striker to make it contact with the second substrate and the first substrate and the second substrate are bonded by using the intermolecular force generated between the bonding surfaces of the first substrate and the second substrate after the surfaces are modified. However, the bonding device is not limited to this, and the bonding device may also be a bonding device of the type that bonds the first substrate and the second substrate with the aid of an adhesive.

[0173] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not restrictive. In fact, the above embodiments can be specifically implemented in a variety of ways. In addition, the above embodiments can be omitted, replaced, and changed in various ways without departing from the attached claims and their gist.

[0174] Description of Reference Numerals

[0175] W1: first substrate; W2: second substrate; T: overlapping substrate; 1: joining system; 2: loading and unloading station; 3: processing station; 4: inspection station; 41: joining device; 70: control device; 71: control unit; 71a: measurement control unit; 71b: reference generating unit; 71c: comparison unit; 71d: determination unit; 71e: re-measurement control unit; 72: storage unit; 72a: inspection result information; 72b: reference information; 80: inspection device; 400: holding unit; 410: main body; 420: supporting member; 460: suction tube; 500: imaging unit; 600: lighting unit.

Claims

1. A joining system comprising: a bonding device for forming a superimposed substrate by bonding the first substrate to the second substrate; an inspection device for inspecting the overlapped substrates; and a control unit that controls the inspection device, in, The control unit comprises: a measurement control unit configured to cause the inspection device to measure the overlapped substrates at a first number of measurement points; a comparing section that compares an inspection result including an offset amount between the first substrate and the second substrate in the superimposed substrates derived from the result of the measurement with a reference; as well as A re-measurement control unit causes the inspection device to re-measure the overlapped substrate using a second number of measurement points greater than the first number of measurement points based on the comparison result of the comparison unit.

2. The joining system according to claim 1, characterized in that The control unit further includes a determination unit, which determines that the first substrate and the second substrate are poorly bonded when the difference between the inspection result and the reference exceeds a first threshold value. The remeasurement control unit causes the inspection device to remeasure the overlapped substrate when the difference between the inspection result and the reference exceeds a second threshold value that is smaller than the first threshold value but does not exceed the first threshold value.

3. The joining system according to claim 1 or 2, characterized in that The control unit further includes a reference generating unit configured to generate the reference of the inspection target overlapped substrate based on the inspection result of an inspected overlapped substrate that was inspected before the inspection target overlapped substrate that is the object of the current inspection.

4. The joining system according to claim 3, characterized in that The reference generating unit generates the reference of the inspection target overlapped substrate based on the inspection results of one or more inspected overlapped substrates that are in the same substrate group as the inspection target overlapped substrate.

5. The joining system according to claim 4, characterized in that The reference generating unit generates the inspection result of the inspected overlapped substrate processed first among the plurality of inspected overlapped substrates of the same substrate group as the reference for the inspected overlapped substrate.

6. The joining system according to claim 4, characterized in that The reference generating unit generates an average value of the inspection results of two or more of the inspected overlapped substrates among a plurality of the inspected overlapped substrates of the same substrate group as the reference of the inspection target overlapped substrate.

7. The joining system according to claim 3, characterized in that The reference generating unit generates the inspection result of the inspected overlapped substrate which is in a substrate group different from the substrate group of the inspected overlapped substrate and has the same processing order as the inspected overlapped substrate in the substrate group unit as the reference of the inspected overlapped substrate.

8. The joining system according to claim 1 or 2, characterized in that: The measurement control unit sets the first number of measurement points only on the outer periphery of the overlapped substrate. The re-measurement control unit sets a total of the second number of measurement points at the outer periphery and the center of the overlapped substrate.

9. The joining system according to claim 1 or 2, characterized in that: The first substrate and the second substrate are single crystal silicon wafers with a surface crystal orientation of [100], When the direction from the center of the overlapping substrate toward the [0-11] crystal direction parallel to the surface of the overlapping substrate is defined as 0 degrees, the measurement control unit sets a measurement point at at least one of the four first peripheral portions arranged at 90 degrees intervals with the direction of 45 degrees as a reference, and at least one of the four second peripheral portions arranged at 90 degrees intervals with the direction of 90 degrees as a reference.

10. A method for inspecting a superimposed substrate, using an inspection device to inspect a superimposed substrate formed by bonding a first substrate and a second substrate, the method comprising the following steps: causing the inspection device to measure the overlapped substrates at a first number of measurement points; comparing an inspection result including an offset amount between the first substrate and the second substrate in the superimposed substrates derived from the measured result with a reference; and Based on the comparison result of the step of performing the comparison, the inspection device is caused to re-measure the overlapped substrate using a second number of measurement points that is larger than the first number of measurement points.

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