Joint device, and information processing method

Abstract

To provide a technology capable of taking various measures by simply recognizing states of a first holding part and a second part or a state of a superposed substrate.SOLUTION: A joint device joins a first substrate and a second substrate to form a superposed substrate. The joint device includes a first holding part for holding the first substrate, a second holding part for holding the second substrate under the first holding part and holding the superposed substrate due to a joint of the first substrate and the second substrate, and a plurality of measurement parts provided on the first holding part to measure a distance to an opposite position. Also, the joint device has an information processing part for recognizing states of the first holding part and the second holding parts or a state of the superposed substrate on the basis of measurement information measured by at least one measurement part among the plurality of measurement parts after joining the first substrate and the second substrate.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present disclosure relates to a joining device and an information processing method. [Background technology]

[0002] Patent Document 1 discloses a bonding device that holds a first substrate (upper wafer) with a first holding unit (upper chuck), holds a second substrate (lower wafer) with a second holding unit (lower chuck), and presses down the first substrate from the first holding unit to bond it to the second substrate, thereby forming a laminated substrate. This bonding device also has multiple measuring units (sensors) that detect the distance of the first substrate held by the first holding unit in order to monitor the progress of bonding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6929427 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that allows the state of the first holding unit and the second holding unit or the state of the superposed substrates to be easily recognized and various measures to be taken. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a bonding device that bonds a first substrate and a second substrate to form an overlapped substrate, the bonding device including: a first holding unit that holds the first substrate; a second holding unit that holds the second substrate below the first holding unit and holds the overlapped substrate as the first substrate and the second substrate are bonded; a plurality of measuring units that are provided on the first holding unit and measure the distance to an opposing position including the first substrate; and an information processing unit that recognizes the state of the first holding unit and the second holding unit or the state of the overlapped substrate based on measurement information measured by at least one of the plurality of measuring units after the first substrate and the second substrate are bonded. [Effects of the Invention]

[0006] According to one aspect, the state of the first holding unit and the second holding unit or the state of the superposed substrates can be easily recognized, and various measures can be taken. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. [Figure 2] FIG. 2 is a side view of the joining device of FIG. [Figure 3] FIG. 2 is a side view showing an example of a first substrate and a second substrate. [Figure 4] 1 is a flowchart showing a joining method. [Figure 5] FIG. 2 is a plan view showing an example of a joining module according to the first embodiment. [Figure 6] FIG. 6 is a side view of the splicing module of FIG. 5; [Figure 7] FIG. 2 is a cross-sectional view showing an example of an upper chuck and a lower chuck. [Figure 8] 5 is a flowchart showing details of step S109 in FIG. 4. [Figure 9] Fig. 9(A) is a side view showing an example of the operation in step S112 of Fig. 8. Fig. 9(B) is a side view showing the operation following Fig. 9(A). Fig. 9(C) is a side view showing the operation following Fig. 9(B). [Figure 10]Fig. 10(A) is a cross-sectional view showing an example of the operation in step S113 of Fig. 8. Fig. 10(B) is a cross-sectional view showing an example of the operation in step S114 of Fig. 8. Fig. 10(C) is a cross-sectional view showing the operation subsequent to Fig. 10(B). [Figure 11] FIG. 10 is a cross-sectional view showing an upper chuck on which a displacement sensor is installed. [Figure 12] FIG. 10 is a plan view showing an example of the placement of a displacement sensor in the upper chuck. [Figure 13] 13A is a cross-sectional view showing the measurement of the upper wafer by each displacement sensor before bonding, and FIG. 13B is a cross-sectional view showing the measurement of the upper wafer by each displacement sensor after bonding. [Figure 14] 10A and 10B are diagrams showing a state in which the change in distance between the upper wafer before and after bonding is detected by each displacement sensor. [Figure 15] 3 is a flowchart showing a processing flow of an information processing method according to the first embodiment. [Figure 16] Fig. 16(A) shows a state in which no slip occurs in the upper wafer when the lower chuck moves, and Fig. 16(B) shows a state in which a slip occurs in the upper wafer when the lower chuck moves. [Figure 17] 10A and 10B are plan views illustrating an example of movement of the lower chuck performed after bonding the upper wafer and the lower wafer. [Figure 18] 18(A) is a diagram showing measurement information from the displacement sensor when there is no misalignment between the upper and lower wafers, and FIG. 18(B) is a diagram showing measurement information from the displacement sensor when there is a misalignment between the upper and lower wafers. [Figure 19] 10A and 10B are diagrams illustrating an example in which the outer shape of the upper surface of the overlapped wafer after bonding is estimated based on measurement information from a displacement sensor. [Figure 20] FIG. 1 is a cross-sectional view illustrating a deformation chuck. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted. Note that the X-axis, Y-axis, and Z-axis directions used in the following description are axes that intersect perpendicularly with each other, the X-axis and Y-axis directions are horizontal directions, and the Z-axis direction is vertical.

[0009] A bonding apparatus 1 shown in FIGS. 1 and 2 will be described as a representative example of a substrate processing apparatus according to the present disclosure. The bonding apparatus 1 bonds a first substrate W1 and a second substrate W2 to produce a laminated substrate T. At least one of the first substrate W1 and the second substrate W2 is a semiconductor substrate, such as a silicon wafer or a compound semiconductor wafer, on which multiple electronic circuits or semiconductor devices are formed. One of the first substrate W1 and the second substrate W2 may be a bare wafer on which no electronic circuits or semiconductor devices are formed. The compound semiconductor wafer may be, but is not limited to, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer.

[0010] The first substrate W1 and the second substrate W2 are formed as circular plates of approximately the same shape (same diameter). As shown in FIG. 3, the bonding apparatus 1 places the second substrate W2 on the negative Z-axis side (vertically below) of the first substrate W1 and bonds the first substrate W1 and the second substrate W2. Therefore, hereinafter, the first substrate W1 may be referred to as the "upper wafer W1," the second substrate W2 as the "lower wafer W2," and the overlapped substrate T as the "overlapping wafer T." Furthermore, hereinafter, the surface of the upper wafer W1 that is bonded to the lower wafer W2 will be referred to as the "bonding surface W1j," and the surface opposite the bonding surface W1j will be referred to as the "non-bonding surface W1n." Furthermore, the surface of the lower wafer W2 that is bonded to the upper wafer W1 will be referred to as the "bonding surface W2j," and the surface opposite the bonding surface W2j will be referred to as the "non-bonding surface W2n."

[0011] 1, the bonding apparatus 1 includes, in order in the positive direction of the X-axis, a carry-in / out station 2 and a processing station 3. The carry-in / out station 2 and the processing station 3 are integrally connected.

[0012] The carry-in / out station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 has a plurality of mounting plates 11. Each mounting plate 11 is loaded with a cassette CS1, CS2, or CS3, which stores a plurality of substrates (e.g., 25 substrates) in a horizontal position. The cassette CS1 stores an upper wafer W1, the cassette CS2 stores a lower wafer W2, and the cassette CS3 stores an overlapped wafer T. In the cassettes CS1 and CS2, the upper wafer W1 and the lower wafer W2 are stored with their bonding surfaces W1j and W2j facing upward and aligned in the same direction.

[0013] The transfer region 20 is disposed adjacent to the mounting table 10 on the positive side of the X axis, and includes a transfer path 21 extending in the Y axis direction, and a transfer device 22 movable along the transfer path 21. The transfer device 22 is movable also in the X axis direction and rotatable about the Z axis, and transfers the upper wafer W1, the lower wafer W2, and the overlapped wafer T between the cassettes CS1 to CS3 placed on the mounting table 10 and a third processing block PB3 of the processing station 3, which will be described later.

[0014] Processing station 3 includes, for example, three processing blocks PB1, PB2, and PB3. The first processing block PB1 is provided on the rear side of processing station 3 (the positive Y-axis side in FIG. 1). The second processing block PB2 is provided on the front side of processing station 3 (the negative Y-axis side in FIG. 1). The third processing block PB3 is provided on the loading / unloading station 2 side of processing station 3 (the negative X-axis side in FIG. 1).

[0015] Processing station 3 also includes a transfer region 60, surrounded by first processing block PB1 to third processing block PB3, through which transfer device 61 moves. For example, transfer device 61 has a transfer arm that is movable vertically, horizontally, and around a vertical axis. Transfer device 61 moves within transfer region 60 and selectively transfers upper wafer W1, lower wafer W2, and overlapped wafer T to devices in first processing block PB1, second processing block PB2, and third processing block PB3 adjacent to transfer region 60.

[0016] The first processing block PB1 includes, for example, a surface modification device 33 and a surface hydrophilization device 34. The surface modification device 33 modifies the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2. The surface hydrophilization device 34 hydrophilizes the modified bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2.

[0017] For example, the surface modification device 33 breaks SiO2 bonds on the bonding surfaces W1j and W2j, forming dangling Si bonds and enabling subsequent hydrophilization. In the surface modification device 33, for example, oxygen gas, which is a processing gas, is excited to plasma and ionized under a reduced pressure. The oxygen ions are then irradiated onto the bonding surfaces W1j of the upper wafer W1 and W2j of the lower wafer W2, thereby subjecting the bonding surfaces W1j and W2j to plasma processing and modification. The processing gas is not limited to oxygen gas, and may be nitrogen gas or the like.

[0018] The surface hydrophilization device 34 hydrophilizes the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 using a hydrophilization treatment liquid such as pure water. The surface hydrophilization device 34 also serves to clean the bonding surfaces W1j and W2j. In the surface hydrophilization device 34, for example, pure water is supplied onto the upper wafer W1 or the lower wafer W2 while rotating the upper wafer W1 or the lower wafer W2 held by a spin chuck. As a result, the pure water diffuses over the bonding surfaces W1j and W2j, attaching OH groups to the dangling Si bonds and hydrophilizing the bonding surfaces W1j and W2j.

[0019] 2, the second processing block PB2 includes, for example, a bonding module 41, a first temperature adjustment device 42, and a second temperature adjustment device 43. The bonding module 41 bonds a hydrophilized upper wafer W1 and a lower wafer W2 to produce a laminated wafer T. The first temperature adjustment device 42 adjusts the temperature distribution of the upper wafer W1 before producing the laminated wafer T. The second temperature adjustment device 43 adjusts the temperature distribution of the lower wafer W2 before producing the laminated wafer T. In this embodiment, the first temperature adjustment device 42 and the second temperature adjustment device 43 are provided separately from the bonding module 41, but they may also be provided as part of the bonding module 41.

[0020] The third processing block PB3 includes, for example, a first position adjustment device 51, a second position adjustment device 52, and transition devices 53 and 54 arranged in this order from top to bottom. Note that the locations of the devices in the third processing block PB3 are not limited to those shown in FIG. 2. The first position adjustment device 51 adjusts the horizontal orientation of the upper wafer W1 and also turns the upper wafer W1 upside down so that the bonding surface W1j of the upper wafer W1 faces downward. The second position adjustment device 52 adjusts the horizontal orientation of the lower wafer W2. The transition device 53 temporarily places the upper wafer W1 thereon. The transition device 54 temporarily places the lower wafer W2 and the overlapped wafer T thereon.

[0021] Returning to FIG. 1 , the bonding apparatus 1 includes a control device 90 that controls each component. The control device 90 is an information processing unit having one or more processors 91, a memory 92, an input / output interface (not shown), and an electronic circuit. The one or more processors 91 are one or a combination of a central processing unit (CCPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit made up of multiple discrete semiconductors, and the like. The memory 92 includes non-volatile memory and volatile memory and forms a storage unit of the control device 90. In other words, in the present disclosure, the control device 90 is an electronic circuit having a CPU, a GPU, an ASIC, an FPGA, etc., and performs various control operations described in this specification by executing instruction codes stored in the memory 92 or by being a circuit designed for a specific application.

[0022] Next, the joining method of this embodiment will be described with reference to Fig. 4. Steps S101 to S109 shown in Fig. 4 are performed under the control of the control device 90.

[0023] In the bonding method, an operator or a transport robot (not shown) places a cassette CS1 containing multiple upper wafers W1, a cassette CS2 containing multiple lower wafers W2, and an empty cassette CS3 on the loading / unloading station 2 on the loading / unloading stage 10.

[0024] The bonding apparatus 1 uses the transfer device 22 to remove the upper wafer W1 from the cassette CS1 and transfer it to the transition device 53 in the third processing block PB3 of the processing station 3. Thereafter, the bonding apparatus 1 uses the transfer device 61 to remove the upper wafer W1 from the transition device 53 and transfer it to the surface modification device 33 in the first processing block PB1.

[0025] Next, the bonding apparatus 1 modifies the bonding surface W1j of the upper wafer W1 using the surface modification device 33 (step S101). The surface modification device 33 modifies the bonding surface W1j with the bonding surface W1j facing upward. Thereafter, the transfer device 61 removes the upper wafer W1 from the surface modification device 33 and transfers it to the surface hydrophilization device 34.

[0026] Then, the bonding apparatus 1 causes the surface hydrophilizing device 34 to hydrophilize the bonding surface W1j of the upper wafer W1 (step S102). The surface hydrophilizing device 34 hydrophilizes the bonding surface W1j with the bonding surface W1j facing upward. Thereafter, the transfer device 61 takes out the upper wafer W1 from the surface hydrophilizing device 34 and transfers it to the first position adjustment device 51 in the third processing block PB3.

[0027] The bonding apparatus 1 adjusts the horizontal orientation of the upper wafer W1 using the first position adjustment device 51 and turns the upper wafer W1 upside down (step S103). As a result, the notch of the upper wafer W1 is oriented in a predetermined direction and the bonding surface W1j of the upper wafer W1 faces downward. Thereafter, the transfer device 61 removes the upper wafer W1 from the first position adjustment device 51 and transfers it to the first temperature adjustment device 42 in the second processing block PB2.

[0028] The bonding apparatus 1 adjusts the temperature of the upper wafer W1 by the first temperature adjustment device 42 (step S104). The temperature adjustment of the upper wafer W1 is performed with the bonding surface W1j of the upper wafer W1 facing downward. Thereafter, the transfer device 61 takes out the upper wafer W1 from the first temperature adjustment device 42 and transfers it to the bonding module 41.

[0029] The bonding apparatus 1 performs processing on the lower wafer W2 in parallel with the above processing on the upper wafer W1. First, the bonding apparatus 1 causes the transfer device 22 to remove the lower wafer W2 from the cassette CS2 and transfer it to the transition device 54 in the third processing block PB3 of the processing station 3. Thereafter, the transfer device 61 removes the lower wafer W2 from the transition device 54 and transfers it to the surface modification device 33 in the first processing block PB1.

[0030] The bonding apparatus 1 modifies the bonding surface W2j of the lower wafer W2 using the surface modification device 33 (step S105). The surface modification device 33 modifies the bonding surface W2j with the bonding surface W2j facing upward. Thereafter, the transfer device 61 removes the lower wafer W2 from the surface modification device 33 and transfers it to the surface hydrophilization device .

[0031] The bonding apparatus 1 hydrophilizes the bonding surface W2j of the lower wafer W2 using the surface hydrophilization device 34 (step S106). The surface hydrophilization device 34 hydrophilizes the bonding surface W2j with the bonding surface W2j facing upward. Thereafter, the transfer device 61 removes the lower wafer W2 from the surface hydrophilization device 34 and transfers it to the second position adjustment device 52 in the third processing block PB3.

[0032] The bonding apparatus 1 adjusts the horizontal orientation of the lower wafer W2 using the second position adjustment device 52 (step S107). This orients the notch of the lower wafer W2 in a predetermined direction. Thereafter, the transfer device 61 removes the lower wafer W2 from the second position adjustment device 52 and transfers it to the second temperature adjustment device 43 in the second processing block PB2.

[0033] The bonding apparatus 1 adjusts the temperature of the lower wafer W2 by the second temperature adjustment device 43 (step S108). The temperature adjustment of the lower wafer W2 is performed with the bonding surface W2j of the lower wafer W2 facing upward. Thereafter, the transfer device 61 takes out the lower wafer W2 from the second temperature adjustment device 43 and transfers it to the bonding module 41.

[0034] Then, the bonding apparatus 1 bonds the upper wafer W1 and the lower wafer W2 in the bonding module 41 to fabricate the overlapped wafer T (step S109). After fabricating the overlapped wafer T, the transfer device 61 removes the overlapped wafer T from the bonding module 41 and transfers it to the transition device 54 in the third processing block PB3.

[0035] Finally, the bonding apparatus 1 causes the transfer device 22 to take out the overlapped wafer T from the transition device 54 and transfer it to the cassette CS3 on the mounting table 10. This completes the series of processes.

[0036] Next, an example of a bonding module 41 according to an embodiment will be described with reference to Fig. 5 to Fig. 7. As shown in Fig. 5, the bonding module 41 has a processing container 210 whose interior can be sealed. A loading / unloading port 211 is formed on the side of the processing container 210 on the transfer region 60 side, and an opening / closing shutter 212 is provided at the loading / unloading port 211. The upper wafer W1, the lower wafer W2, and the overlapping wafer T are loaded and unloaded through the loading / unloading port 211.

[0037] 6, an upper chuck 230 and a lower chuck 231 are provided inside the processing vessel 210. The upper chuck 230 is a first holding part that releasably (displaceably) holds the upper wafer W1 from above with the bonding surface W1j of the upper wafer W1 facing downward. The lower chuck 231 is a second holding part that is located below the upper chuck 230 and holds the lower wafer W2 from below with the bonding surface W2j of the lower wafer W2 facing upward. In other words, the upper chuck 230 and the lower chuck 231 are holding parts that releasably hold the upper wafer W1 and the lower wafer W2, which are substrates.

[0038] The upper chuck 230 is attached to a support member 220 provided on the ceiling surface of the processing vessel 210. The support member 220 has a plurality of position adjustment mechanisms 221 that support the upper chuck 230, and each position adjustment mechanism 221 can adjust and maintain the vertical position of the upper chuck 230. For example, four position adjustment mechanisms 221 are provided, and each position adjustment mechanism 221 supports both ends of the upper chuck 230 in the X-axis direction and both ends of the upper chuck 230 in the Y-axis direction at four points. The bonding module 41 adjusts the vertical position of the upper wafer W1 by each position adjustment mechanism 221 when, for example, receiving the upper wafer W1 relative to the upper chuck 230. The number of position adjustment mechanisms 221 is not particularly limited, and may be three (three-point support) or five or more.

[0039] Each position adjustment mechanism 221 is connected to the control device 90, and by adjusting the vertical position based on the control of the control device 90, the attitude of the upper chuck 230, in other words, the inclination of the suction surface (holding surface) of the upper chuck 230, can be changed. The bonding module 41 basically bonds the upper wafer W1 and the lower wafer W2 in a state where the suction surface of the upper chuck 230 and the suction surface (holding surface) of the lower chuck 231 are parallel to each other. Each position adjustment mechanism 221 can adjust the inclination angle (parallelism) between the suction surface of the upper chuck 230 and the suction surface of the lower chuck 231 by changing the attitude of the upper chuck 230.

[0040] On the other hand, the lower chuck 231 is supported by a first lower chuck moving part 291 provided below the lower chuck 231. The first lower chuck moving part 291 moves the lower chuck 231 in the horizontal direction (Y-axis direction), as will be described later. In addition, the first lower chuck moving part 291 is configured to be able to move the lower chuck 231 vertically and to rotate it around a vertical axis.

[0041] The first lower chuck moving part 291 is provided on the underside of the first lower chuck moving part 291 and is attached to a pair of rails 295 extending in the horizontal direction (Y-axis direction). The first lower chuck moving part 291 is configured to be movable along the rails 295. The rails 295 are provided on a second lower chuck moving part 296.

[0042] The second lower chuck moving part 296 is provided on the lower surface side of the second lower chuck moving part 296 and is attached to a pair of rails 297 extending in the horizontal direction (X-axis direction). The second lower chuck moving part 296 is configured to be movable along the rails 297. The pair of rails 297 is provided on a mounting part 298 provided on the bottom surface of the processing vessel 210.

[0043] The first lower chuck moving part 291 and the second lower chuck moving part 296 constitute a moving mechanism 290. The moving mechanism 290 moves the lower chuck 231 relative to the upper chuck 230. The moving mechanism 290 also moves the lower chuck 231 between a substrate transfer position and a bonding position.

[0044] The substrate transfer position is a position where the upper chuck 230 receives the upper wafer W1 from the transfer device 61, the lower chuck 231 receives the lower wafer W2 from the transfer device 61, and the lower chuck 231 transfers the overlapped wafer T to the transfer device 61. The substrate transfer position is a position where the overlapped wafer T produced in the nth (n is a natural number greater than or equal to 1) bonding is successively transferred out and the upper wafer W1 and lower wafer W2 to be bonded in the n+1th bonding are transferred in. The substrate transfer position is, for example, a position shown in FIGS. 5 and 6.

[0045] The transfer device 61 enters directly below the upper chuck 230 when transferring the upper wafer W1 to the upper chuck 230. Furthermore, the transfer device 61 enters directly above the lower chuck 231 when receiving the overlapped wafer T from the lower chuck 231 and transferring the lower wafer W2 to the lower chuck 231. To facilitate the transfer device 61's entry, the upper chuck 230 and the lower chuck 231 are shifted laterally, and the vertical distance between the upper chuck 230 and the lower chuck 231 is also large.

[0046] On the other hand, the bonding position is a position (opposing position) where the upper wafer W1 and the lower wafer W2 are faced to each other with a predetermined gap therebetween. The bonding position is, for example, the position shown in FIG. 7. At the bonding position, the gap between the upper wafer W1 and the lower wafer W2 in the vertical direction is narrower than at the substrate transfer position. Also, at the bonding position, unlike at the substrate transfer position, the upper wafer W1 and the lower wafer W2 overlap when viewed in the vertical direction.

[0047] The moving mechanism 290 moves the relative positions of the upper chuck 230 and the lower chuck 231 in the horizontal direction (both the X-axis direction and the Y-axis direction) and the vertical direction. In this embodiment, the moving mechanism 290 moves the lower chuck 231, but it may move either the lower chuck 231 or the upper chuck 230, or may move both. The moving mechanism 290 may also rotate the upper chuck 230 or the lower chuck 231 around a vertical axis.

[0048] 7, the upper chuck 230 is partitioned into a plurality of (for example, three) regions 230a, 230b, and 230c along the radial direction of the upper chuck 230. These regions 230a, 230b, and 230c are provided in this order from the center toward the outer edge of the upper chuck 230. The region 230a is formed in a perfect circular shape in a plan view, and the regions 230b and 230c are formed in annular shapes in a plan view.

[0049] Suction pipes 240a, 240b, and 240c are provided independently for the respective regions 230a, 230b, and 230c. Different vacuum pumps 241a, 241b, and 241c are connected to the respective suction pipes 240a, 240b, and 240c. The upper chuck 230 can vacuum-suck the upper wafer W1 for each of the regions 230a, 230b, and 230c.

[0050] The upper chuck 230 has a plurality of radially and annularly extending ribs, the protruding ends of which form suction surfaces. The suction pipes 240a, 240b, and 240c communicate with the pipe installation bottom surfaces between the ribs, and apply suction pressure to the spaces between the upper wafer W1, the ribs, and the pipe installation bottom surfaces, thereby suctioning the upper wafer W1.

[0051] The upper chuck 230 is provided with a plurality of holding pins 245 that can be raised and lowered in the vertical direction. The plurality of holding pins 245 are connected to a vacuum pump 246, and vacuum-suck the upper wafer W1 by operating the vacuum pump 246. The upper wafer W1 is vacuum-sucked to the lower ends of the plurality of holding pins 245. Ring-shaped suction pads may be used instead of the plurality of holding pins 245.

[0052] The multiple holding pins 245 are lowered by a drive unit (not shown) to protrude from the chucking surface of the upper chuck 230. In this state, the multiple holding pins 245 vacuum-suck the upper wafer W1 and receive it from the transfer device 61. Thereafter, the multiple holding pins 245 rise, and the upper wafer W1 comes into contact with the chucking surface of the upper chuck 230. Next, the upper chuck 230 vacuum-sucks the upper wafer W1 horizontally in each of the regions 230a, 230b, and 230c by operating the vacuum pumps 241a, 241b, and 241c.

[0053] The upper chuck 230 also has a through-hole 243 at its center that passes through the upper chuck 230 in the vertical direction. A pushing unit 250 is inserted into the through-hole 243. The pushing unit 250 pushes down the center of the upper wafer W1, which is disposed at an interval from the lower wafer W2, to bring the upper wafer W1 into contact with the lower wafer W2.

[0054] The pushing unit 250 has a pushing pin 251 and an outer cylinder 252 that serves as a lifting guide for the pushing pin 251. The pushing pin 251 is inserted into the through-hole 243 by, for example, a drive unit (not shown) having a built-in motor, protrudes from the suction surface of the upper chuck 230, and pushes down the center of the upper wafer W1.

[0055] The lower chuck 231 is also partitioned into a plurality of (for example, two) regions 231a and 231b along the radial direction of the lower chuck 231. These regions 231a and 231b are provided in this order from the center of the lower chuck 231 toward the outer edge. The region 231a is formed in a perfect circular shape in a plan view, and the region 231b is formed in an annular shape in a plan view. The region 231b may have a plurality of arc-shaped zones (small regions) along the circumferential direction.

[0056] Suction pipes 260a and 260b are provided independently for the respective regions 231a and 231b. Different vacuum pumps 261a and 261b are connected to the respective suction pipes 260a and 260b. This allows the lower chuck 231 to vacuum-suck the lower wafer W2 for each of the regions 231a and 231b.

[0057] The lower chuck 231 is provided with a plurality of (for example, three) holding pins 265 that can be raised and lowered in the vertical direction. The lower wafer W2 is placed on the upper ends of the plurality of holding pins 265. The lower wafer W2 may be vacuum-sucked to the upper ends of the plurality of holding pins 265.

[0058] As the multiple holding pins 265 rise, they protrude from the suction surface of the lower chuck 231. In this state, the multiple holding pins 265 receive the lower wafer W2 from the transfer device 61. Thereafter, the multiple holding pins 265 descend, causing the lower wafer W2 to come into contact with the suction surface of the lower chuck 231. Next, the lower chuck 231 horizontally vacuum-sucks the lower wafer W2 in multiple regions of the suction surface.

[0059] Next, the process of producing the overlapped wafer T in step S109 of Fig. 4 will be described in detail with reference to Fig. 8 to Fig. 10. As shown in Fig. 8, the control device 90 causes the transfer device 61 to load the upper wafer W1 and the lower wafer W2 into the bonding module 41 (step S111). After the loading, the relative position of the upper chuck 230 and the lower chuck 231 is the substrate transfer position shown in Figs. 6 and 7.

[0060] Next, the control device 90 causes the moving mechanism 290 to move the relative positions of the upper chuck 230 and the lower chuck 231 from the substrate transfer position to the bonding position shown in Fig. 7 (step S112). In this step S112, the control device 90 aligns the upper wafer W1 and the lower wafer W2 using the first camera S1 and the second camera S2 as shown in Fig. 9.

[0061] The first camera S1 is fixed to the upper chuck 230 and captures an image of the lower wafer W2 held by the lower chuck 231. A plurality of reference points P21 to P23 are formed in advance on the bonding surface W2j of the lower wafer W2. The reference points P21 to P23 are formed by using patterns of electronic circuits or the like. The number of reference points can be set arbitrarily.

[0062] On the other hand, the second camera S2 is fixed to the lower chuck 231 and captures an image of the upper wafer W1 held by the upper chuck 230. A plurality of reference points P11 to P13 are formed in advance on the bonding surface W1j of the upper wafer W1. The reference points P11 to P13 are formed by using patterns of electronic circuits or the like. The number of reference points can be set arbitrarily.

[0063] 9(A), the joining module 41 adjusts the relative horizontal positions of the first camera S1 and the second camera S2 using the movement mechanism 290. Specifically, the movement mechanism 290 moves the lower chuck 231 in the horizontal direction so that the second camera S2 is positioned approximately directly below the first camera S1. Then, the first camera S1 and the second camera S2 capture an image of a common target X, and the movement mechanism 290 finely adjusts the horizontal position of the second camera S2 so that the horizontal positions of the first camera S1 and the second camera S2 match.

[0064] 9(B), the movement mechanism 290 moves the lower chuck 231 vertically upward to adjust the horizontal positions of the upper chuck 230 and the lower chuck 231. Specifically, while the movement mechanism 290 moves the lower chuck 231 horizontally, the first camera S1 sequentially captures images of reference points P21 to P23 on the lower wafer W2, and the second camera S2 sequentially captures images of reference points P11 to P13 on the upper wafer W1. Note that FIG. 9(B) shows how the first camera S1 captures the image of reference point P21 on the lower wafer W2, and the second camera S2 captures the image of reference point P11 on the upper wafer W1.

[0065] The first camera S1 and the second camera S2 transmit the captured image data to the control device 90. The control device 90 controls the movement mechanism 290 based on the image data captured by the first camera S1 and the image data captured by the second camera S2, and adjusts the horizontal position of the lower chuck 231 so that the reference points P11 to P13 of the upper wafer W1 and the reference points P21 to P23 of the lower wafer W2 coincide with each other when viewed in the vertical direction.

[0066] 9(C), the moving mechanism 290 moves the lower chuck 231 vertically upward. As a result, the gap G (see FIG. 7) between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 becomes a predetermined distance, for example, 80 μm to 200 μm. The gap G is adjusted using the first displacement gauge S3 and the second displacement gauge S4.

[0067] The first displacement meter S3, like the first camera S1, is fixed to the upper chuck 230 and measures the thickness of the lower wafer W2 held by the lower chuck 231. The first displacement meter S3 measures the thickness of the lower wafer W2 by, for example, irradiating light onto the lower wafer W2 and receiving light reflected from both the upper and lower surfaces of the lower wafer W2. This thickness measurement is performed, for example, when the movement mechanism 290 moves the lower chuck 231 in the horizontal direction. The measurement method of the first displacement meter S3 is, for example, a confocal method, a spectral interference method, or a triangulation method. The light source of the first displacement meter S3 is an LED or a laser.

[0068] On the other hand, the second displacement meter S4, like the second camera S2, is fixed to the lower chuck 231 and measures the thickness of the upper wafer W1 held by the upper chuck 230. The second displacement meter S4 measures the thickness of the upper wafer W1 by, for example, irradiating light onto the upper wafer W1 and receiving light reflected from both the upper and lower surfaces of the upper wafer W1. This thickness measurement is performed, for example, when the movement mechanism 290 moves the lower chuck 231 in the horizontal direction. The measurement method of the second displacement meter S4 is, for example, a confocal method, a spectral interference method, or a triangulation method. The light source of the second displacement meter S4 is an LED or a laser.

[0069] The first displacement meter S3 and the second displacement meter S4 transmit the measured data to the control device 90. The control device 90 controls the moving mechanism 290 based on the data measured by the first displacement meter S3 and the data measured by the second displacement meter S4, and adjusts the vertical position of the lower chuck 231 so that the gap G becomes a set value.

[0070] Next, the operation of the vacuum pump 241a is stopped, and the vacuum suction of the upper wafer W1 in the region 230a is released, as shown in Fig. 10(A). Thereafter, the pushing pin 251 of the pushing unit 250 descends to push down the center of the upper wafer W1, thereby bringing the upper wafer W1 into contact with the lower wafer W2 (step S113). As a result, the centers of the upper wafer W1 and the lower wafer W2 are bonded together.

[0071] Because the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified, van der Waals forces (intermolecular forces) are generated between the bonding surfaces W1j and W2j, bonding the bonding surfaces W1j and W2j together. Furthermore, because the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been hydrophilized, hydrophilic groups (e.g., OH groups) form hydrogen bonds, firmly bonding the bonding surfaces W1j and W2j together.

[0072] Next, the control device 90 stops the operation of the vacuum pump 241b, and releases the vacuum suction of the upper wafer W1 in the region 230b as shown in Fig. 10(B). Subsequently, the control device 90 stops the operation of the vacuum pump 241c, and releases the vacuum suction of the upper wafer W1 in the region 230c as shown in Fig. 10(C).

[0073] In this way, the vacuum suction of the upper wafer W1 is gradually released from the center toward the periphery of the upper wafer W1, and the upper wafer W1 gradually drops and contacts the lower wafer W2. Then, the bonding of the upper wafer W1 and the lower wafer W2 proceeds sequentially from the center toward the periphery (step S114). As a result, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into contact over their entire surfaces, the upper wafer W1 and the lower wafer W2 are bonded, and the overlapped wafer T is obtained. Thereafter, the bonding apparatus 1 raises the pushing pin 251 to its original position.

[0074] After the overlapped wafer T is formed, the control device 90 causes the moving mechanism 290 to move the relative positions of the upper chuck 230 and the lower chuck 231 from the bonding position shown in Fig. 7 to the substrate transfer position shown in Fig. 5 and Fig. 6 (step S115). For example, the moving mechanism 290 first lowers the lower chuck 231 to widen the vertical gap between the lower chuck 231 and the upper chuck 230. Next, the moving mechanism 290 moves the lower chuck 231 laterally to laterally shift the lower chuck 231 and the upper chuck 230.

[0075] Thereafter, the control device 90 causes the transfer device 61 to transfer the overlapped wafer T out of the bonding module 41 (step S116). Specifically, first, the lower chuck 231 releases the hold of the overlapped wafer T. Next, the multiple holding pins 265 rise and transfer the overlapped wafer T to the transfer device 61. Thereafter, the multiple holding pins 265 descend to their original positions.

[0076] 11, the above-described bonding apparatus 1 has a plurality of displacement sensors 270 for measuring the height position of the upper wafer W1 in the upper chuck 230 in order to monitor the progress of bonding (bonding wave) between the upper wafer W1 and the lower wafer W2. The displacement sensors 270 are measurement units that irradiate the upper wafer W1 with measurement light and receive reflected light from the upper wafer W1 to obtain measurement information.

[0077] The multiple displacement sensors 270 (multiple measurement units) are, for example, lined up radially outward from the center of the upper chuck 230, and are arranged at equal intervals along the circumferential direction at the same radial position. As an example, the multiple displacement sensors 270 include three displacement sensors 270 at different radial positions, which are provided in each of regions 230a, 230b, and 230c set in the upper chuck 230. Hereinafter, the displacement sensor 270 located in region 230a will also be referred to as inner displacement sensor 270a, the displacement sensor 270 located in region 230b will also be referred to as middle displacement sensor 270b, and the displacement sensor 270 located in region 230c will also be referred to as outer displacement sensor 270c.

[0078] Each displacement sensor 270 (inner displacement sensor 270a, middle displacement sensor 270b, and outer displacement sensor 270c) is installed to face the upper wafer W1 held by the upper chuck 230. The upper chuck 230 has an arrangement portion 275 for arranging each displacement sensor 270. The arrangement portion 275 includes a recess 276 that accommodates part or all of the displacement sensor 270, a fixing portion 277 that fixes the displacement sensor 270, and an aperture 278 that connects the recess 276 to a space on the chucking surface side of the upper chuck 230. Each fixing portion 277 fixes each displacement sensor 270 so that the tips (lower ends) of the displacement sensors 270 are at the same height. The aperture 278 is formed through the bottom of the recess 276 and tapers toward the chucking surface, thereby narrowing the range of the measurement light of the displacement sensor 270.

[0079] Each displacement sensor 270 arranged in the arrangement part 275 can measure the distance from the tip of the displacement sensor 270 to the surface (non-bonding surface W1n) of the opposing upper wafer W1 through the space from the tip of the displacement sensor 270 to the upper wafer W1. Furthermore, the displacement sensor 270 is connected to the control device 90 so as to be able to communicate information, and transmits acquired information to the control device 90 under the command of the control device 90 or automatically. The control device 90 functions as an information processing part that processes information from each displacement sensor 270.

[0080] For example, a white light confocal sensor that emits white (multicolor) measurement light onto the upper wafer W1 and measures distance using information about the light reflected from the surface (non-bonding surface W1n) of the upper wafer W1 can be applied to each displacement sensor 270. The white light confocal displacement sensor 270 includes a housing, a white LED, and a lens module that focuses the measurement light emitted from the white LED for each color (for each of multiple wavelengths) at different positions on the optical axis.

[0081] For example, the displacement sensor 270 sets the focal length of blue light to the farthest position, the focal length of red light to the closest position, and the focal length of green light to be set somewhere in between. Light of a color (wavelength) focused on the upper surface of the upper wafer W1 is most strongly reflected. Therefore, the displacement sensor 270 can measure the relative distance between the displacement sensor 270 and the upper wafer W1 based on the peak wavelength of the reflection spectrum. The order and distance of the focal positions of the red, green, and blue light are not particularly limited and may be set arbitrarily depending on the device to be used. By using a white light confocal displacement sensor 270 in this way, the displacement sensor 270 does not need to come into contact with the upper wafer W1 during measurement and can achieve high measurement accuracy. However, the displacement sensor 270 is not limited to a confocal sensor; various optical sensors, such as a spectral interference sensor or a triangulation sensor, may also be used.

[0082] As shown in FIG. 12, the displacement sensors 270 are installed in the X-axis direction, Y-axis direction, and diagonal directions (at intermediate positions) between the X-axis direction and the Y-axis direction of the upper chuck 230. Thus, for example, eight outer displacement sensors 270c are arranged at equal intervals (45° intervals) along the circumferential direction of the region 230c of the upper chuck 230. The same is true for the intermediate displacement sensors 270b and the inner displacement sensors 270a. However, the number and installation positions of the displacement sensors 270 may be greater or less than this. For example, two inner displacement sensors 270a may be provided in the X-axis direction and two in the Y-axis direction, but they may not be provided in the diagonal directions. Furthermore, the displacement sensors 270 may be installed at the center of the upper chuck 230 (see the dashed line in FIG. 12). As described above, the pushing portion 250 is provided at the center of the upper chuck 230, and the displacement sensor 270 provided at the center is preferably fixed to the outer cylinder 252 at a position adjacent to the pushing pin 251 of the pushing portion 250.

[0083] Each of the displacement sensors 270 measures the distance between the upper wafer W1 and the lower wafer W2 during bonding of the upper wafer W1 and the lower wafer W2, thereby determining the height position of the upper wafer W1. The control device 90 monitors the measurement information from each of the displacement sensors 270 to determine the progress of bonding between the upper wafer W1 and the lower wafer W2, i.e., the bonding wave. For example, at the start of bonding, when the pressing unit 250 presses down the center of the upper wafer W1, the control device 90 primarily monitors the measurement information from each of the inner displacement sensors 270a to determine the timing to release suction on the region 230b. Furthermore, during the bonding process, the control device 90 primarily monitors the measurement information from each of the intermediate displacement sensors 270b to determine the timing to release suction on the region 230c. Furthermore, at the end of bonding, the control device 90 primarily monitors the measurement information from each of the outer displacement sensors 270c to determine the completion of bonding of the upper wafer W1 and the lower wafer W2.

[0084] Here, the conventional bonding apparatus uses the measurement information of each displacement sensor only when bonding the upper wafer W1 and the lower wafer W2 as described above, but does not use the measurement information of each displacement sensor after bonding the upper wafer W1 and the lower wafer W2, etc. In other words, the conventional bonding apparatus uses each displacement sensor only to monitor the progress of bonding the upper wafer W1 and the lower wafer W2.

[0085] Therefore, the bonding apparatus 1 according to the embodiment is configured to use measurement information measured by at least one displacement sensor 270 to recognize the states of the upper chuck 230 and the lower chuck 231 or the state of the overlapped wafer T even after the upper wafer W1 and the lower wafer W2 are bonded. Below, examples of using the measurement information of each displacement sensor 270 after bonding will be described for each of four embodiments.

[0086] First Embodiment In the first embodiment shown in FIGS. 13A and 13B, the control device 90 of the bonding apparatus 1 recognizes the states of the upper chuck 230 and the lower chuck 231 after bonding using the measurement information of each displacement sensor 270. Specifically, the control device 90 recognizes the inclination angle between the suction surface (holding surface) of the upper chuck 230 and the suction surface (holding surface) of the lower chuck 231 based on the measurement information of each displacement sensor 270, and adjusts the posture of the upper chuck 230. The suction surfaces of the upper chuck 230 and the lower chuck 231 are parallel and face each other, thereby suppressing misalignment between the upper wafer W1 and the lower wafer W2 and improving the formation accuracy of the overlapped wafer T. That is, during bonding, the suction surfaces of the upper chuck 230 and the lower chuck 231 are required to be constantly parallel to each other. However, the parallelism may slightly change due to, for example, the operation of the pressing unit 250 during bonding, vibrations due to suction, or other disturbances. Therefore, the control device 90 is configured to calculate the tilt angle by acquiring the height position of the upper wafer W1 before bonding and the height position of the upper wafer W1 (overlapping wafer T) after bonding using each displacement sensor 270.

[0087] 13(A), the upper chuck 230 attracts and holds the upper wafer W1 at the bonding position before bonding. The control device 90 acquires the distance to the upper wafer W1 using each displacement sensor 270 at this timing before bonding. In particular, when recognizing the inclination angle between the attracting surface (holding surface) of the upper chuck 230 and the attracting surface (holding surface) of the lower chuck 231, it is preferable to use measurement information from multiple outer displacement sensors 270c, which makes it easy to determine the inclination of the two attracting surfaces. Because the upper wafer W1 is attracted to the attracting surface of the upper chuck 230 before bonding, it can be said that the measurement information from each outer displacement sensor 270c indicates each height position (vertical position) of the outer periphery of the attracting surface of the upper chuck 230.

[0088] 13(A), the measurement information of each outer displacement sensor 270c before bonding has approximately the same value. The control device 90 stores this measurement information of each outer displacement sensor 270c before bonding and uses it as a reference position for later recognizing the tilt angle. In other words, the reference position is information indicating the zero point (zero reset) of the measurement information of the displacement sensor 270.

[0089] 13(B), after the upper wafer W1 and the lower wafer W2 are bonded together, the upper wafer W1 is spaced apart to a certain extent from the chucking surface of the upper chuck 230. At the timing after this bonding, the control device 90 acquires the distance to the upper wafer W1 using each displacement sensor 270 (particularly, each outer displacement sensor 270c).

[0090] Here, when the suction surfaces of the upper chuck 230 and the lower chuck 231 are parallel to each other (when the tilt angle is zero), the measurement information of each outer displacement sensor 270c after bonding has approximately the same value. This is because the upper wafer W1 is spaced apart in a direction perpendicular to the suction surface of the upper chuck 230 and supported parallel to the lower wafer W2 of the lower chuck 231.

[0091] 13(B), when the suction surfaces of the upper chuck 230 and the lower chuck 231 are not parallel (when the tilt angle is other than zero), the measurement information of each outer displacement sensor 270c has a different value. For example, the distance of the measurement information of the outer displacement sensor 270c on the side where the suction surface of the upper chuck 230 is closer to the suction surface of the lower chuck 231 becomes shorter, and the distance of the measurement information of the outer displacement sensor 270c on the side where the suction surface of the upper chuck 230 is farther from the suction surface of the lower chuck 231 becomes longer.

[0092] 14, the control device 90 can recognize the displacement of the upper wafer W1 after bonding relative to the upper wafer W1 before bonding by subtracting the reference position (measurement information of each outer displacement sensor 270c before bonding) from the measurement information of each outer displacement sensor 270c after bonding. The displacement of the upper wafer W1 before and after bonding depends on the inclination angle (parallelism) between the suction surfaces of the upper chuck 230 and the lower chuck 231. Therefore, the control device 90 can calculate the inclination angle between the suction surfaces of the upper chuck 230 and the lower chuck 231 based on the measurement information of each outer displacement sensor 270c.

[0093] Furthermore, the control device 90 can calculate a correction amount to make the tilt angle between the chucking surface of the upper chuck 230 and the chucking surface of the lower chuck 231 zero based on the obtained displacement at the installation position of each outer displacement sensor 270c. For example, the control device 90 calculates the correction amount by fitting a linear equation with two unknowns to the displacement of the upper wafer W1 at each outer displacement sensor 270c. After calculating this correction amount, the control device 90 adjusts the tilt of the upper chuck 230 by operating each position adjustment mechanism 221 supporting the upper chuck 230 based on the correction amount. This allows the bonding apparatus 1 to return the chucking surface of the upper chuck 230 and the chucking surface of the lower chuck to be parallel (to zero the tilt angle). Note that, in the example of FIG. 13, a pattern in which the chucking surface of the upper chuck 230 is inclined has been described. However, even in a pattern in which the chucking surface of the lower chuck 231 is inclined, the chucking surfaces of the upper chuck 230 and the chucking surface of the lower chuck can be made parallel by a similar method.

[0094] Hereinafter, an information processing method for the measurement information of each displacement sensor 270 according to the first embodiment will be described with reference to the flowchart of Fig. 15. When bonding the upper wafer W1 and the lower wafer W2, the control device 90 sequentially executes steps S121 to S127 shown in Fig. 15 to adjust the inclination angle between the suction surfaces of the upper chuck 230 and the lower chuck 231 based on the measurement information of each displacement sensor 270.

[0095] First, the control device 90 detects the height position of the upper wafer W1 before bonding using each displacement sensor 270 (each outer displacement sensor 270c) in a state where the upper wafer W1 is sucked by the upper chuck 230 and placed at the bonding position (step S121). As described above, the measurement information of each outer displacement sensor 270c coincides with the suction surface of the upper chuck 230. The control device 90 stores this measurement information in the memory 92 as reference data for adjusting the tilt angle.

[0096] Thereafter, the control device 90 controls each component of the bonding module 41 to perform steps S122 and S123, thereby bonding the upper wafer W1 and the lower wafer W2. Step S122 is the same as step S113 in Fig. 8, and step S123 is the same as step S114 in Fig. 8, so detailed descriptions thereof will be omitted.

[0097] In bonding the upper wafer W1 and the lower wafer W2, the control device 90 recognizes the progress of bonding by detecting the distance to the non-bonding surface W1n of the upper wafer W1 using each displacement sensor 270, and determines whether bonding is complete (step S124). If bonding is not complete (step S124: NO), step S124 is repeated to monitor the progress of bonding. On the other hand, if it is determined that bonding is complete (step S124: YES), the process proceeds to step S125.

[0098] In step S125, the control device 90 detects the height position of the upper wafer W1 after bonding using each displacement sensor 270 (each outer displacement sensor 270c) and stores the detected height position in the memory 92. This enables the control device 90 to recognize the displacement of the upper wafer W1 before and after bonding.

[0099] Thereafter, the control device 90 calculates the inclination angle between the suction surface of the upper chuck 230 and the suction surface of the lower chuck 231 based on the height position of the upper wafer W1 before bonding and the height position of the upper wafer W1 after bonding, which are stored in the memory 92 (step S126). Furthermore, in calculating the inclination angle, the control device 90 performs fitting as described above, and can calculate the correction amount of each position adjustment mechanism 221.

[0100] Finally, the control device 90 controls each position adjustment mechanism 221 based on the calculated correction amount to adjust the position of the upper chuck 230 (or the lower chuck 231) (step S127). Note that the control device 90 may hold an angle threshold for comparison with the calculated tilt angle, and perform processing such as not performing position adjustment when the tilt angle is less than the angle threshold, and performing position adjustment when the tilt angle is equal to or greater than the angle threshold.

[0101] As described above, the control device 90 can accurately recognize the tilt angles of the suction surfaces of the upper chuck 230 and the lower chuck 231 by using the measurement information of each displacement sensor 270 before and after bonding. The control device 90 controls the operation of each position adjustment mechanism 221 based on the recognized tilt angles, thereby making the suction surfaces of the upper chuck 230 and the lower chuck 231 parallel to each other. As a result, the bonding apparatus 1 can bond the upper wafer W1 and the lower wafer W2 while keeping the upper chuck 230 and the lower chuck 231 always parallel to each other. In particular, since the bonding apparatus 1 obtains the tilt angle at the bonding position, it is possible to obtain a more accurate value than conventional measurement methods.

[0102] Furthermore, the control device 90 recognizes the reference position based on the measurement information of each displacement sensor 270 before bonding, and can accurately recognize the tilt angle by using the measurement information of each displacement sensor 270 after bonding and the reference position. This allows the bonding device 1 to take appropriate measures, such as adjusting the attitude of the upper chuck 230 or the lower chuck 231.

[0103] Second Embodiment 16(A) and 16(B) differs from the first embodiment in that slippage between the upper wafer W1 and the lower wafer W2 is detected based on measurement information from each displacement sensor 270 when the lower chuck 231 moves after the upper wafer W1 and the lower wafer W2 are bonded together. Specifically, the overlapped wafer T is subjected to acceleration of the horizontal sliding caused by the movement mechanism 290 of the lower chuck 231. This acceleration may cause the upper wafer W1 to slip relative to the lower wafer W2. This slippage of the upper wafer W1 basically occurs in the direction opposite (e.g., the negative X-axis direction) to the moving direction of the lower chuck 231 (e.g., the positive X-axis direction).

[0104] Therefore, each displacement sensor 270 continues to detect the upper surface (non-bonding surface W1n of the upper wafer W1) of the overlapped wafer T during the movement of the lower chuck 231 when the overlapped wafer T is unloaded from the processing chamber 210. The control device 90 continuously receives measurement information from each displacement sensor 270 and recognizes slip of the upper wafer W1 based on the period during which each displacement sensor 270 detects the upper wafer W1.

[0105] Here, if no slip occurs between the upper wafer W1 and the lower wafer W2, the period during which each displacement sensor 270 detects the upper wafer W1 is a period estimated in advance depending on the moving speed of the lower wafer W2. In particular, the outer displacement sensor 270c on the positive X-axis side (in other words, located at the leading edge in the moving direction) which faces the overlapping wafer T for the longest period in the moving direction of the lower wafer W2, detects the upper wafer W1 for a long period and is therefore easily usable as a sensor for monitoring positional deviation.

[0106] On the other hand, if slippage occurs between the upper wafer W1 and the lower wafer W2, the period during which each displacement sensor 270 detects the upper wafer W1 will differ from the period expected depending on the moving speed of the lower wafer W2. When the upper wafer W1 slips in the direction opposite to the moving direction (negative direction of the X-axis), for example, the outer displacement sensor 270c on the positive side of the X-axis will detect the upper wafer W1 for a period longer than the expected period. Note that in this process, the measurement information of each displacement sensor 270 may not use the distance to the upper wafer W1, but may use the on / off switching of the sensor.

[0107] Therefore, the control device 90 compares the period (measurement information) during which the upper wafer W1 is detected by the outer displacement sensor 270c at the forefront side in the movement direction with the period threshold. If the detection period of the upper wafer W1 is less than the period threshold, the control device 90 can determine that no slippage of the upper wafer W1 relative to the lower wafer W2 has occurred. On the other hand, if the detection period of the upper wafer W1 is equal to or greater than the period threshold, the control device 90 can determine that slippage of the upper wafer W1 relative to the lower wafer W2 has occurred.

[0108] If a slip occurs between the upper wafer W1 and the lower wafer W2, the bonding of the overlapped wafer T will be defective. Therefore, the bonding apparatus 1 can take measures in accordance with the bonding defect of the overlapped wafer T (for example, discarding or peeling the overlapped wafer T, notifying the user, etc.) at an early stage.

[0109] As described above, in the second embodiment, by determining whether or not a slip has occurred between the upper wafer W1 and the lower wafer W2 as the state of the overlapped wafer T, bonding defects of the overlapped wafer T can be easily recognized and various countermeasures can be taken. This information processing method can be executed in parallel with the unloading of the overlapped wafer T, so it is possible to eliminate the conventional step of detecting with another optical sensor. Therefore, the bonding apparatus 1 can shorten the cycle time.

[0110] <Third embodiment> 17, 18(A), and 18(B) differs from the first and second embodiments in that, after bonding the upper wafer W1 and the lower wafer W2, the lower chuck 231 is intentionally moved back and forth by the moving mechanism 290 to measure the outer periphery (edge) of the overlapped wafer T based on measurement information from each displacement sensor 270. That is, in the third embodiment, the positional deviation between the upper wafer W1 and the lower wafer W2 that occurs during the formation of the overlapped wafer T is recognized based on measurement information from each displacement sensor 270 (particularly the outer displacement sensor 270c).

[0111] 17, the lower chuck 231 is slid by the moving mechanism 290 in both the X-axis direction (first direction) and the Y-axis direction (second direction perpendicular to the first direction). The outer displacement sensors 270c provided on both sides of the upper chuck 230 in the X-axis direction and the Y-axis direction can detect the non-bonding surface W1n of the overlapped wafer T, the outer edge of the overlapped wafer T, and the chucking surface of the lower chuck 231 as the lower chuck 231 slides. Note that the moving mechanism 290 is not limited to moving in the X-axis direction and the Y-axis direction, and may adopt various movement patterns.

[0112] For example, as shown in the left diagram of Fig. 18(A), when there is no misalignment between the upper wafer W1 and the lower wafer W2 of the overlapped wafer T, the outer displacement sensor 270c facing that location detects measurement information as shown in the right diagram of Fig. 18(A). This measurement information indicates a height position value corresponding to the thickness of the upper wafer W1 and the lower wafer W2 at the location facing the overlapped wafer T, and indicates a value at the outer edge of the overlapped wafer T where the height position suddenly drops to the chucking surface of the lower chuck 231.

[0113] On the other hand, when the upper wafer W1 and the lower wafer W2 of the overlapped wafer T are misaligned as shown in the left diagram of Fig. 18(B), the outer displacement sensor 270c facing that location detects measurement information as shown in the right diagram of Fig. 18(B). This measurement information indicates height position values ​​corresponding to the thicknesses of the upper wafer W1 and the lower wafer W2, and indicates a height position corresponding to the thickness of the lower wafer W2 where the thickness of the upper wafer W1 disappears at the outer edge of the overlapped wafer T, and further indicates a stepped value that decreases to the chucking surface of the lower chuck 231.

[0114] That is, when the control device 90 detects a step-like change in height position of the outer edge of the overlapped wafer T by each outer displacement sensor 270c during movement of the lower chuck 231 in the X-axis direction and the Y-axis direction, the control device 90 can recognize that a positional deviation has occurred between the upper wafer W1 and the lower wafer W2. For example, the control device 90 has a dimensional threshold corresponding to the step-like length of the upper wafer W1 and the lower wafer W2 (the exposed range of the lower wafer W2), and when the control device 90 detects a step-like change in height position, the control device 90 compares the step-like length with the dimensional threshold.

[0115] When the length of the stepped portion is less than the dimensional threshold, the control device 90 can determine that no misalignment has occurred between the upper wafer W1 and the lower wafer W2. On the other hand, when the length of the stepped portion is equal to or greater than the dimensional threshold, the control device 90 can determine that a misalignment has occurred between the upper wafer W1 and the lower wafer W2. When a misalignment between the upper wafer W1 and the lower wafer W2 is determined, measures can be taken promptly in response to a bonding defect of the overlapped wafer T (for example, discarding or peeling the overlapped wafer T, notifying the user, etc.).

[0116] As described above, in the third embodiment, by determining whether or not misalignment has occurred between the upper wafer W1 and the lower wafer W2 as the state of the overlapped wafer T, bonding defects of the overlapped wafer T can be easily recognized and various countermeasures can be taken. In particular, in the bonding module 41, when the misalignment between the upper wafer W1 and the lower wafer W2 is reproducible, the bonding accuracy can be improved by correcting the positions of the upper chuck 230 and the lower chuck 231 according to the amount of misalignment (the length of the stepped shape). Furthermore, the control device 90 can determine whether or not the outer edge of the overlapped wafer T is lifted, based on the measurement information.

[0117] The control device 90 can also adjust the resolution when measuring the outer edge of the overlapped wafer T by adjusting the moving speed of the lower chuck 231 by the moving mechanism 290. For example, the moving mechanism 290 can perform measurement with higher accuracy by slowing down the moving speed at a position where each outer displacement sensor 270c faces the vicinity of the outer edge of the overlapped wafer T.

[0118] <Fourth embodiment> 19 differs from the first to third embodiments in that the outer shape of the entire upper surface of the overlapped wafer T after bonding the upper wafer W1 and the lower wafer W2 is recognized based on measurement information from each displacement sensor 270 (all of the displacement sensors 270 of the upper chuck 230). That is, by using the measurement information from each displacement sensor 270, the control device 90 can estimate the height position of the entire overlapped wafer T after bonding.

[0119] Specifically, the control device 90 can accurately estimate the overall shape of the overlapped wafer T by fitting a two-dimensional quadratic equation as shown in Fig. 19 to the plot of the height positions detected by each displacement sensor 270. In Fig. 19, high height positions are shown in black, low height positions are shown in white, and height changes are represented in grayscale. For example, when a deformation chuck 232 as shown in Fig. 20 is applied to the lower chuck 231, the bonding device 1 can monitor whether the overlapped wafer T has an expected shape by taking into account the amount of deformation of the lower chuck 231.

[0120] The deformation chuck 232 includes, for example, a base portion 233 and a suction portion 234. The suction portion 234 is provided above the base portion 233 and suction-holds the lower wafer W2 from below by suction from a vacuum pump 234p. The suction portion 234 is fixed to the base portion 233 by a fixing ring 235 provided on the periphery. A pressure variable space 236 is formed between the upper surface of the base portion 233 and the lower surface of the suction portion 234.

[0121] The deformation chuck 232 includes a vacuum pump 237, a pressure pump 238, and a switching valve 239 that change the pressure in the pressure variable space 236, thereby elastically deforming the suction portion 234. The vacuum pump 237 reduces the pressure in the pressure variable space 236 by discharging gas therein, thereby horizontalizing the suction surface of the suction portion 234. The pressure pump 238 pressurizes the pressure variable space 236 by supplying gas therein, thereby curved (hemispherical) the suction surface of the suction portion 234. The protrusion amount of the central region of the suction surface can be adjusted by the pressure in the pressure variable space 236. The base 233 also includes a measurement mechanism 233a that measures the protrusion amount of the central region A of the suction surface. The measurement mechanism 233a is, for example, a capacitance sensor, and measures the protrusion amount of the suction surface by detecting capacitance that changes depending on the distance from the displacing suction portion.

[0122] The lower chuck 231 (deformation chuck 232) described above deforms the lower wafer W2 while bonding it to the upper wafer W1, thereby suppressing, for example, warpage of the lower wafer W2 (or warpage of the upper wafer W1) and forming the overlapped wafer T with high precision. When the deformation chuck 232 is used, the control device 90 can estimate the overall contour of the overlapped wafer T based on measurement information of the non-bonding surface W1n of the upper wafer W1 obtained by each displacement sensor 270. This allows the control device 90 to optimize the recipe for the next bonding method using this estimated shape data of the overlapped wafer T. For example, the control device 90 can adjust the amount of deformation of the overlapped wafer T. Furthermore, the control device 90 can recognize variations between lots of the formed overlapped wafer T and changes over time. It goes without saying that the bonding apparatus 1 can also use a flat chuck (see also FIG. 7 ) without the deformation chuck 232 to capture the overall contour of the overlapped wafer T, thereby providing useful control for various purposes.

[0123] Furthermore, in the above, the information processing methods for the measurement information of each displacement sensor 270 have been described separately for the first to fourth embodiments. However, it goes without saying that the bonding apparatus 1 can recognize the states of the upper chuck 230 and the lower chuck 231 or the state of the overlapped wafer T simultaneously or at different times by combining a plurality of the first to fourth embodiments.

[0124] The bonding device 1 and the information processing method according to the presently disclosed embodiments are illustrative in all respects and are not limiting. The embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The matters described in the above-described embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent. [Explanation of symbols]

[0125] 1 Bonding equipment 90 Control device 230 Upper chuck 231 Lower zipper 270 Displacement Sensor T Polymerized wafer (polymerized substrate) W1 Upper wafer (first substrate) W2 Lower wafer (second substrate)

Claims

1. A bonding apparatus for bonding a first substrate and a second substrate to form a laminated substrate, a first holding portion that holds the first substrate; a second holding portion that holds the second substrate below the first holding portion and holds the laminated substrate in conjunction with bonding of the first substrate and the second substrate; a plurality of measuring units provided on the first holding unit to measure a distance to an opposing position including the first substrate; and an information processing unit that recognizes a state of the first holding unit and the second holding unit or a state of the laminated substrate based on measurement information measured by at least one of the plurality of measurement units after the first substrate and the second substrate are bonded. Bonding equipment.

2. The information processing unit monitoring a progress of bonding based on measurement information from the plurality of measurement units during bonding of the first substrate and the second substrate; determining completion of the bonding based on the measurement information of the plurality of measurement units, and then recognizing states of the first holding unit and the second holding unit or a state of the laminated substrate based on the measurement information of the measurement units; The joining device according to claim 1 .

3. The plurality of measurement units are arranged in a radial direction of the first holding unit, the information processing unit recognizes the states of the first holding unit and the second holding unit or the state of the laminated substrate using measurement information from the measurement unit located radially outside the first holding unit. The joining device according to claim 1 .

4. The information processing unit calculating an inclination angle between a holding surface on which the first holding unit holds the first substrate and a holding surface on which the second holding unit holds the second substrate based on measurement information from the measuring unit after the first substrate and the second substrate are bonded; The joining device according to any one of claims 1 to 3.

5. The information processing unit Recognizing a reference position based on measurement information of the measurement unit before the first substrate and the second substrate are bonded; calculating the tilt angle based on the measurement information of the measurement unit after the first substrate and the second substrate are bonded and the reference position; The joining device according to claim 4 .

6. a position adjustment mechanism for adjusting the position of the first holding portion; the information processing unit controls the operation of the position adjustment mechanism based on the calculated tilt angle so that a holding surface that holds the first substrate and a holding surface on which the second holding unit holds the second substrate are parallel to each other. The joining device according to claim 4 .

7. a moving mechanism that moves the second holding part in a horizontal direction, The information processing unit determining whether or not slippage has occurred between the first substrate and the second substrate based on measurement information from the measurement unit when the second holding unit moves after the first substrate and the second substrate are joined; The joining device according to any one of claims 1 to 3.

8. The information processing unit determining whether or not slippage has occurred between the first substrate and the second substrate based on measurement information from the measurement unit located at the leading end of the second holding unit in the movement direction; The joining device according to claim 7.

9. a moving mechanism that moves the second holding part in a horizontal direction, The information processing unit After the first substrate and the second substrate are bonded, the second holding unit is moved and the outer edge of the laminated substrate is measured by the measuring unit, thereby determining whether or not a positional deviation has occurred between the first substrate and the second substrate. The joining device according to any one of claims 1 to 3.

10. the moving mechanism moves the second holding unit in a first direction and a second direction perpendicular to the first direction in measuring the outer edge of the laminated substrate. The joining device according to claim 9.

11. The information processing unit after the first substrate and the second substrate are bonded, recognizing an outer shape of the laminated substrate based on the measurement information of all the measurement units; The joining device according to claim 1 or 2.

12. 1. An information processing method for a bonding device that forms a laminated substrate by bonding a first substrate held by a first holding unit and a second substrate held by a second holding unit below the first holding unit, and holds the laminated substrate by the second holding unit, measuring a distance to an opposing position including the first substrate by a plurality of measuring units provided in the first holding unit after the first substrate and the second substrate are bonded; and recognizing a state of the first holding unit and the second holding unit or a state of the laminated substrate based on measurement information measured by at least one of the plurality of measurement units. Information processing methods.

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