Joining device and joining method

Abstract

To provide a technique for improving alignment accuracy before bonding.SOLUTION: A bonding apparatus bonds a first substrate having a first alignment mark and a second substrate having a second alignment mark. When a first imaging unit images the second alignment mark, a first irradiation unit irradiates an imaging area of the first imaging unit with white light. When a second imaging unit images the first alignment mark, a second irradiation unit irradiates an imaging area of the second imaging unit with white light. A control unit detects positions of the first alignment mark and the second alignment mark by processing images captured by the first imaging unit and the second imaging unit. The control unit corrects the detected position of the first alignment mark on the basis of a relationship between the wavelength and the intensity of reflected light reflected on the first substrate. The control unit controls a moving unit on the basis of the corrected position of the first alignment mark.SELECTED DRAWING: Figure 8

Description

Technical Field

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

Background Art

[0002] The bonding device described in Patent Document 1 bonds a first substrate having a first alignment mark and a second substrate having a second alignment mark. The bonding device includes a first holding part, a second holding part, a first imaging part, a first irradiation part, a second imaging part, a second irradiation part, and a control part. The first holding part holds the first substrate. The second holding part holds the second substrate. When the first imaging part images the second alignment mark, the first irradiation part irradiates white light onto the imaging area of the first imaging part. When the second imaging part images the first alignment mark, the second irradiation part irradiates white light onto the imaging area of the second imaging part. The control part detects the positions of the first alignment mark and the second alignment mark by processing the images captured by the first imaging part and the second imaging part, and aligns the first substrate and the second substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One aspect of the present disclosure provides a technique for improving the alignment accuracy before bonding.

Means for Solving the Problems

[0005] A bonding apparatus according to one aspect of the present disclosure bonds a first substrate including a first alignment mark to a second substrate including a second alignment mark. The bonding apparatus comprises a first holding unit, a second holding unit, a first imaging unit, a first irradiating unit, a second imaging unit, a second irradiating unit, a moving unit, and a control unit. The first holding unit holds the first substrate. The second holding unit holds the second substrate. The first imaging unit is provided in the first holding unit and images the second substrate held in the second holding unit. The first irradiating unit irradiates the imaging area of ​​the first imaging unit with white light when the first imaging unit images the second alignment mark. The second imaging unit is provided in the second holding unit and images the first substrate held in the first holding unit. The second irradiating unit irradiates the imaging area of ​​the second imaging unit with white light when the second imaging unit images the first alignment mark. The moving unit moves the first holding unit and the second holding unit relative to each other. The control unit controls the moving unit. The control unit detects the positions of the first alignment mark and the second alignment mark by processing the images captured by the first imaging unit and the second imaging unit, corrects the detected position of the first alignment mark based on the relationship between the wavelength and intensity of the reflected light reflected by the first substrate, and controls the moving unit based on the corrected position of the first alignment mark. The second imaging unit has a color camera, which includes a first color light-receiving element and a second color light-receiving element that receive light of different colors. The control unit corrects the position of the first alignment mark based on the ratio of the light-receiving intensity of the first color light-receiving element and the second color light-receiving element that constitute the same pixel. [Effects of the Invention]

[0006] According to one aspect of this disclosure, the alignment accuracy before joining can be improved. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a plan view showing a joining system according to one embodiment. [Figure 2] Figure 2 is a cross-sectional view showing an example of a polymerized wafer obtained by joining a lower wafer to an upper wafer. [Figure 3] Figure 3 is a flowchart showing a joining method according to one embodiment. [Figure 4] Figure 4 is a cross-sectional view showing an example of a joining device. [Figure 5] Figure 5 is a flowchart showing an example of step S105. [Figure 6] Figure 6(A) is a side view showing an example of the operation in step S112, Figure 6(B) is a side view showing the operation following Figure 6(A), and Figure 6(C) is a side view showing the operation following Figure 6(B). [Figure 7] Figure 7(A) is a cross-sectional view showing an example of the operation in step S113, Figure 7(B) is a cross-sectional view showing an example of the operation in step S114, and Figure 7(C) is a cross-sectional view showing the operation following Figure 7(B). [Figure 8] Figure 8 is a cross-sectional view showing an example of the upper imaging unit, upper illumination unit, and upper spectrometer. [Figure 9] Figure 9 shows an example of an image captured of the lower alignment mark. [Figure 10] Figure 10 shows an example of a reflectance spectrum. [Figure 11] Figure 11 is a diagram showing an example of the components of the control unit in terms of functional blocks. [Figure 12] Figure 12 is a cross-sectional view showing a first modified example of the upper imaging unit and the upper illumination unit. [Figure 13] Figure 13 is a cross-sectional view showing a second modified example of the upper imaging unit and the upper illumination unit. [Figure 14] Figure 14 is a cross-sectional view showing a third modified example of the upper imaging unit and the upper illumination unit. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their descriptions may be omitted. The X-axis, Y-axis, and Z-axis directions are perpendicular to each other, the X-axis and Y-axis directions are horizontal, and the Z-axis direction is vertical.

[0009] Referring to FIG. 1, a bonding system 1 according to an embodiment will be described. The bonding system 1 bonds a first substrate and a second substrate to produce a polymerized substrate. As shown in FIG. 2, the substrate disposed on the lower side during bonding is referred to as the lower wafer W1, and the substrate disposed on the upper side during bonding is referred to as the upper wafer W2. The lower wafer W1 corresponds to the first substrate, and the upper wafer W2 corresponds to the second substrate, but the combination may be reversed, and the lower wafer W1 may correspond to the second substrate and the upper wafer W2 may correspond to the first substrate.

[0010] By bonding the lower wafer W1 and the upper wafer W2, a polymerized wafer T is obtained. Among the plate surfaces of the lower wafer W1, the plate surface on the side bonded to the upper wafer W2 is described as the "bonding surface W1j", and the plate surface on the side opposite to the bonding surface W1j is described as the "non-bonding surface W1n". Also, among the plate surfaces of the upper wafer W2, the plate surface on the side bonded to the lower wafer W1 is described as the "bonding surface W2j", and the plate surface on the side opposite to the bonding surface W2j is described as the "non-bonding surface W2n".

[0011] The lower wafer W1 has a semiconductor substrate W1a such as a silicon wafer and a film W1b formed on the semiconductor substrate W1a. Instead of the semiconductor substrate W1a, a glass substrate may be used. The film W1b has, for example, a device layer and a bonding layer. The device layer includes a plurality of electronic circuits. The bonding layer is formed on the device layer. The bonding layer is, for example, a silicon oxide film, a silicon nitride film, or a silicon carbonitride film.

[0012] The bonding layer is formed by a thermal oxidation method, a CVD (Chemical Vapor Depositon) method, an ALD (Atomic Layer Deposition) method, or the like. When a silicon oxide film is formed as the bonding layer by the CVD method, for example, TEOS (Tetra Ethoxy Silane) is used as a raw material for the silicon oxide film.

[0013] The lower wafer W1 has lower alignment marks M11 to M13. The lower alignment marks M11 to M13 are used for horizontal alignment of the lower wafer W1 and the upper wafer W2 before bonding. The lower alignment marks M11 to M13 are formed, for example, between the semiconductor substrate W1a and the film W1b. The arrangement and number of the lower alignment marks M11 to M13 are not limited to those shown in the figure.

[0014] Similarly, the upper wafer W2 has a semiconductor substrate W2a such as a silicon wafer and a film W2b formed on the semiconductor substrate W2a. Instead of the semiconductor substrate W2a, a glass substrate may be used. The film W2b has, for example, a device layer and a bonding layer. The device layer includes a plurality of electronic circuits. The bonding layer is formed on the device layer. The bonding layer is, for example, a silicon oxide film, a silicon nitride film, or a silicon carbonitride film.

[0015] The upper wafer W2 has upper alignment marks M21 to M23. The upper alignment marks M21 to M23 are used for horizontal alignment of the lower wafer W1 and the upper wafer W2 before bonding. The upper alignment marks M21 to M23 are formed, for example, between the semiconductor substrate W2a and the film W2b. The arrangement and number of the upper alignment marks M21 to M23 are not limited to those shown in the figure.

[0016] The lower alignment marks M11 to M13 correspond to the first alignment marks, and the upper alignment marks M21 to M23 correspond to the second alignment marks, but their combination may be reversed, that is, the lower alignment marks M11 to M13 may correspond to the second alignment marks and the upper alignment marks M21 to M23 may correspond to the first alignment marks.

[0017] Note that one of the lower wafer W1 and the upper wafer W2 may not have a device layer.

[0018] As shown in Figure 1, the joining system 1 comprises an input / output station 2 and a processing station 3. The input / output station 2 and the processing station 3 are arranged in the order of input / output station 2 and processing station 3 along the positive X-axis. The input / output station 2 and the processing station 3 are also integrally connected.

[0019] The loading / unloading station 2 comprises a mounting table 10 and a transport area 20. The mounting table 10 comprises a plurality of mounting plates 11. Each mounting plate 11 is fitted with cassettes C1, C2, and C3, which accommodate multiple substrates (for example, 25) in a horizontal position. Cassette C1 is a cassette for accommodating the lower wafer W1, cassette C2 is a cassette for accommodating the upper wafer W2, and cassette C3 is a cassette for accommodating the polymerized wafer T. In cassettes C1 and C2, the lower wafer W1 and upper wafer W2 are arranged in the same orientation with their bonding surfaces W1j and W2j facing upwards, respectively.

[0020] The transport area 20 is positioned adjacent to the positive X-axis side of the mounting table 10. The transport area 20 is provided with a transport path 21 extending in the Y-axis direction and a transport device 22 that is movable along this transport path 21. The transport device 22 has transport arms that hold and transport the lower wafer W1, the upper wafer W2, or the superimposed wafer T. The transport arms are movable in the horizontal and vertical directions and are rotatable around the vertical axis. There may be multiple transport arms. The transport arms transport the upper wafer W2, the lower wafer W1, or the superimposed wafer T to a predetermined device adjacent to the transport area 20.

[0021] The number of cassettes C1 to C3 placed on the mounting base 10 is not limited to those shown in the illustration. In addition, cassettes for collecting faulty circuit boards, etc., may be placed on the mounting base 10 in addition to cassettes C1, C2, and C3.

[0022] Processing station 3 is provided with, for example, three processing blocks G1, G2, and G3. For example, the first processing block G1 is provided on the rear side of processing station 3 (the positive Y-axis side in Figure 1), and the second processing block G2 is provided on the front side of processing station 3 (the negative Y-axis side in Figure 1). In addition, the third processing block G3 is provided on the loading / unloading station 2 side of processing station 3 (the negative X-axis side in Figure 1).

[0023] Furthermore, a transport area 60 is formed in the region enclosed by the first processing block G1 to the third processing block G3. A transport device 61 is arranged in the transport area 60. The transport device 61 has transport arms that hold and transport the lower wafer W1, the upper wafer W2, or the superimposed wafer T. The transport arms are movable in the horizontal and vertical directions and are rotatable around the vertical axis. There may be multiple transport arms. The transport arms transport the lower wafer W1, the upper wafer W2, or the superimposed wafer T to a predetermined device adjacent to the transport area 60.

[0024] The first processing block G1 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 lower wafer W1 or the bonding surface W2j of the upper wafer W2 with plasma. The surface hydrophilization device 34 hydrophilizes the modified bonding surface W1j of the lower wafer W1 or the modified bonding surface W2j of the upper wafer W2. The positions of the surface modification device 33 and the surface hydrophilization device 34 are not limited to those shown in the figure. There may be multiple surface modification devices 33 and surface hydrophilization devices 34.

[0025] The surface modification apparatus 33, for example, breaks the SiO2 bonds at the bonding surfaces W1j and W2j, forming unbonded Si bonds and enabling subsequent hydrophilization. In the surface modification apparatus 33, for example, under a reduced pressure atmosphere, oxygen gas, which is the processing gas, is excited, plasma-generated, and ionized. Then, the bonding surfaces W1j and W2j are irradiated with oxygen ions, thereby plasma-treated and modified. The processing gas is not limited to oxygen gas; for example, nitrogen gas may also be used.

[0026] The surface hydrophilization device 34, for example, imparts OH groups to the bonding surfaces W1j and W2j. The surface hydrophilization device 34 supplies pure water onto the lower wafer W1 or upper wafer W2, while rotating the lower wafer W1 or upper wafer W2, which is held in a spin chuck, for example. The pure water diffuses over the bonding surfaces W1j and W2j, imparting OH groups to the unbonded Si, and hydrophilizing the bonding surfaces W1j and W2j. The surface hydrophilization device 34 also has the role of cleaning the bonding surfaces W1j and W2j.

[0027] In the second processing block G2, for example, a bonding apparatus 41 is arranged. The bonding apparatus 41 inverts the upper wafer W2 so that the bonding surface W2j of the upper wafer W2 faces downward. Then, the bonding apparatus 41 bonds the hydrophilized lower wafer W1 and the upper wafer W2 to produce a polymerized wafer T. In this embodiment, the apparatus for inverting the upper wafer W2 is provided as part of the bonding apparatus 41, but it may be provided separately from the bonding apparatus 41.

[0028] In the third processing block G3, for example, a transition device 51 is located. The transition device 51 temporarily stores the lower wafer W1, the upper wafer W2, or the polymerized wafer T. There may be multiple transition devices 51.

[0029] The bonding system 1 includes a control device 90. The control device 90 is, for example, a computer and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as memory. The storage medium 92 stores programs that control various processes performed in the bonding system 1. The control device 90 controls the operation of the bonding system 1 by causing the CPU 91 to execute the programs stored in the storage medium 92.

[0030] Next, the joining method of this embodiment will be described with reference to Figure 3. The joining method includes, for example, steps S101 to S105. Steps S101 to S105 are performed under the control of the control device 90. Note that the joining method does not have to include all of steps S101 to S105, and only needs to include at least step S105. Furthermore, the joining method may include processes other than step S105.

[0031] First, cassette C1 containing multiple lower wafers W1, cassette C2 containing multiple upper wafers W2, and an empty cassette C3 are placed on the loading platform 10 of the loading / unloading station 2.

[0032] Next, the transport device 22 removes the lower wafer W1 from the cassette C1 and transports it to the transition device 51. After that, the transport device 61 removes the lower wafer W1 from the transition device 51 and transports it to the surface modification device 33.

[0033] Next, the surface modification apparatus 33 modifies the bonding surface W1j of the lower wafer W1 (step S101). The modification of the bonding surface W1j is performed with the bonding surface W1j facing upwards. After that, the transport apparatus 61 removes the lower wafer W1 from the surface modification apparatus 33 and transports it to the surface hydrophilization apparatus 34.

[0034] Next, the surface hydrophilization device 34 hydrophilizes the bonding surface W1j of the lower wafer W1 (step S102). The hydrophilization of the bonding surface W1j is performed with the bonding surface W1j facing upwards. After that, the transport device 61 removes the lower wafer W1 from the surface hydrophilization device 34 and transports it to the bonding device 41.

[0035] In parallel with the above processing on the lower wafer W1, the following processing is performed on the upper wafer W2. First, the transport device 22 takes out the upper wafer W2 from the cassette C2 and transports it to the transition device 51. Then, the transport device 61 takes out the upper wafer W2 from the transition device 51 and transports it to the surface modification device 33.

[0036] Next, the surface modification device 33 modifies the bonding surface W2j of the upper wafer W2 (step S103). The modification of the bonding surface W2j is performed with the bonding surface W2j facing upwards. After that, the transport device 61 removes the upper wafer W2 from the surface modification device 33 and transports it to the surface hydrophilization device 34.

[0037] Next, the surface hydrophilization device 34 hydrophilizes the bonding surface W2j of the upper wafer W2 (step S104). The hydrophilization of the bonding surface W2j is performed with the bonding surface W2j facing upwards. After that, the transport device 61 removes the upper wafer W2 from the surface hydrophilization device 34 and transports it to the bonding device 41.

[0038] Next, the bonding apparatus 41 inverts the upper wafer W2 so that the bonding surface W2j of the upper wafer W2 faces downward. Then, the bonding apparatus 41 bonds the lower wafer W1 and the upper wafer W2 to manufacture a polymerized wafer T (step S105). After that, the transport apparatus 61 removes the polymerized wafer T from the bonding apparatus 41 and transports it to the transition apparatus 51.

[0039] Finally, the transport device 22 removes the polymerized wafer T from the transition device 51 and transports it to the cassette C3 on the mounting table 10. This completes the series of processes.

[0040] Next, an example of the bonding device 41 will be described with reference to Figure 4. The bonding device 41 comprises a lower holding unit 110, an upper holding unit 120, a lower imaging unit 130, an upper imaging unit 150, a moving unit 170, and a control unit 200.

[0041] The lower holding portion 110 holds the lower wafer W1 from below with its bonding surface W1j facing upward. The upper holding portion 120 holds the upper wafer W2 from above with its bonding surface W2j facing downward. The lower holding portion 110 corresponds to the first holding portion, and the upper holding portion 120 corresponds to the second holding portion, but their combination may be reversed.

[0042] The lower imaging unit 130 is located on the lower holding unit 110 and images the upper wafer W2 held by the upper holding unit 120. The upper imaging unit 150 is located on the upper holding unit 120 and images the lower wafer W1 held by the lower holding unit 110. The lower imaging unit 130 corresponds to the first imaging unit and the upper imaging unit 150 corresponds to the second imaging unit, but their combination may be reversed.

[0043] The movable part 170 moves the lower holding part 110 and the upper holding part 120 relative to each other in the horizontal and vertical directions. In this embodiment, the movable part 170 moves the lower holding part 110, but it may also move the upper holding part 120. The movable part 170 may also rotate the lower holding part 110 or the upper holding part 120 around a vertical axis.

[0044] The control unit 200 controls the operation of the bonding device 41. The control unit 200 is, for example, a computer and is configured similarly to the control device 90. The control unit 200 may also be part of the control device 90.

[0045] The lower holding portion 110 is divided into multiple (for example, two) regions 110a and 110b. These regions 110a and 110b are arranged in this order from the center to the periphery of the lower holding portion 110. Region 110a has a circular shape in plan view, and region 110b has an annular shape in plan view.

[0046] Each region 110a and 110b is independently provided with suction tubes 111a and 111b. Each suction tube 111a and 111b is connected to a different vacuum pump 112a and 112b, respectively. The lower holding section 110 is capable of vacuum-adsorbing the lower wafer W1 in each region 110a and 110b.

[0047] The lower holding section 110 is provided with a plurality of holding pins 115 that can move up and down vertically. The lower wafer W1 is placed on the upper ends of the plurality of holding pins 115. Alternatively, the lower wafer W1 may be vacuum-suctioned to the upper ends of the plurality of holding pins 115.

[0048] As the multiple retaining pins 115 rise, they protrude from the retaining surface of the lower retaining section 110. In this state, the multiple retaining pins 115 receive the lower wafer W1 from the transport device 61. Subsequently, the multiple retaining pins 115 descend, and the lower wafer W1 is brought into contact with the retaining surface of the lower retaining section 110. Next, the lower retaining section 110 horizontally vacuum-suctions the lower wafer W1 in each region 110a and 110b by the operation of the vacuum pumps 112a and 112b.

[0049] The upper holding portion 120 is divided into a plurality (for example, three) of regions 120a, 120b, and 120c. These regions 120a, 120b, and 120c are arranged in this order from the center to the periphery of the upper holding portion 120. Region 120a has a circular shape in plan view, and regions 120b and 120c have annular shapes in plan view.

[0050] Each of the regions 120a, 120b, and 120c is independently provided with suction tubes 121a, 121b, and 121c. Each of the suction tubes 121a, 121b, and 121c is connected to a different vacuum pump 122a, 122b, and 122c, respectively. The upper holding section 120 is capable of vacuum-suctioning the upper wafer W2 in each of the regions 120a, 120b, and 120c.

[0051] The upper holding section 120 is provided with a plurality of holding pins 125 that can move up and down vertically. The plurality of holding pins 125 are connected to a vacuum pump 126, and the upper wafer W2 is vacuum-adsorbed by the operation of the vacuum pump 126. The upper wafer W2 is vacuum-adsorbed to the lower ends of the plurality of holding pins 125. A ring-shaped suction pad may be used instead of the plurality of holding pins 125.

[0052] The multiple retaining pins 125 descend, causing them to protrude from the retaining surface of the upper retaining section 120. In this state, the multiple retaining pins 125 vacuum-suction the upper wafer W2 and receive it from the transport device 61. Subsequently, the multiple retaining pins 125 rise, bringing the upper wafer W2 into contact with the retaining surface of the upper retaining section 120. Next, the upper retaining section 120 horizontally vacuum-suctions the upper wafer W2 in each region 120a, 120b, and 120c by operating the vacuum pumps 122a, 122b, and 122c.

[0053] Furthermore, a through-hole 123 is formed in the center of the upper holding portion 120, penetrating the upper holding portion 120 vertically. A pushing portion 190, which will be described later, is inserted through the through-hole 123. The pushing portion 190 pushes down the center of the upper wafer W2, which is positioned at a distance from the lower wafer W1, and brings it into contact with the lower wafer W1.

[0054] The pushing section 190 includes a pushing pin 191 and an outer cylinder 192 which is a lifting guide for the pushing pin 191. The pushing pin 191 is inserted through the through hole 123 by, for example, a drive unit (not shown) that has a built-in motor, protrudes from the holding surface of the upper holding section 120, and pushes down the center of the upper wafer W2.

[0055] Next, an example of the operation of the bonding apparatus 41 will be described with reference to Figures 5 to 7. First, the transport device 61 loads the lower wafer W1 and the upper wafer W2 into the bonding apparatus 41 (step S111). The lower holding unit 110 holds the lower wafer W1 from below with the bonding surface W1j of the lower wafer W1 facing upward. The upper holding unit 120 holds the upper wafer W2 from above with the bonding surface W2j of the upper wafer W2 facing downward.

[0056] Next, the moving unit 170 moves the lower holding unit 110 and the upper holding unit 120 relative to each other to perform alignment of the lower wafer W1 and the upper wafer W2 (step S112). As shown in Figure 6, the lower imaging unit 130 and the upper imaging unit 150 are used for alignment. The upper imaging unit 150 is fixed to the upper holding unit 120 and images the bonding surface W1j of the lower wafer W1 held by the lower holding unit 110. On the other hand, the lower imaging unit 130 is fixed to the lower holding unit 110 and images the bonding surface W2j of the upper wafer W2 held by the upper holding unit 120.

[0057] First, as shown in Figure 6(A), the moving unit 170 performs horizontal alignment of the lower imaging unit 130 and the upper imaging unit 150. Specifically, the moving unit 170 moves the lower holding unit 110 horizontally so that the lower imaging unit 130 is positioned approximately directly below the upper imaging unit 150. Then, the moving unit 170 fine-tunes the horizontal position of the lower imaging unit 130 so that the upper imaging unit 150 and the lower imaging unit 130 capture a common target X and their horizontal positions coincide. This completes the horizontal alignment of the upper imaging unit 150 and the lower imaging unit 130.

[0058] Next, as shown in Figure 6(B), the moving unit 170 moves the lower holding unit 110 vertically upward, and then performs horizontal alignment of the lower holding unit 110 and the upper holding unit 120. Specifically, while the moving unit 170 moves the lower holding unit 110 horizontally, the upper imaging unit 150 sequentially images the lower alignment marks M11 to M13, and the lower imaging unit 130 sequentially images the upper alignment marks M21 to M23. Figure 6(B) shows the upper imaging unit 150 imaging the lower alignment mark M11 and the lower imaging unit 130 imaging the upper alignment mark M23.

[0059] The lower imaging unit 130 and the upper imaging unit 150 transmit the captured image data to the control unit 200. The control unit 200 processes the images captured by the lower imaging unit 130 and the upper imaging unit 150 to detect the positions of the lower alignment marks M11-M13 and the upper alignment marks M21-M23. The control unit 200 controls the movement unit 170 so that the lower alignment marks M11-M13 and the upper alignment marks M21-M23 overlap in a vertical view.

[0060] Next, as shown in Figure 6(C), the moving part 170 moves the lower holding part 110 vertically upward. As a result, the distance G (see Figure 4) between the bonding surface W1j of the lower wafer W1 and the bonding surface W2j of the upper wafer W2 becomes a predetermined distance, for example, 80 μm to 200 μm.

[0061] Next, as shown in Figure 7(A), the operation of the vacuum pump 122a is stopped, and the vacuum adsorption of the upper wafer W2 in region 120a is released. Subsequently, the push pin 191 of the push unit 190 descends, pushing down the center of the upper wafer W2 and bringing it into contact with the lower wafer W1 (step S113). As a result, the centers of the lower wafer W1 and the upper wafer W2 are joined together.

[0062] Since the bonding surface W1j of the lower wafer W1 and the bonding surface W2j of the upper wafer W2 have both been modified, van der Waals forces (intermolecular forces) are generated between the bonding surfaces W1j and W2j, and these bonding surfaces W1j and W2j are joined together. Furthermore, since the bonding surfaces W1j and W2j have both been hydrophilized, hydrophilic groups (e.g., OH groups) form hydrogen bonds, and the bonding surfaces W1j and W2j are firmly joined together.

[0063] Next, as shown in Figure 7(B), the operation of the vacuum pump 122b is stopped, and the vacuum adsorption of the upper wafer W2 in region 120b is released. Subsequently, the operation of the vacuum pump 122c is stopped, and as shown in Figure 7(C), the vacuum adsorption of the upper wafer W2 in region 120c is released.

[0064] In this way, the vacuum adsorption of the upper wafer W2 is gradually released from the center toward the periphery, and the upper wafer W2 gradually falls toward the lower wafer W1 and makes contact. Then, the bonding of the lower wafer W1 and the upper wafer W2 proceeds sequentially from the center toward the periphery (step S114). As a result, the bonding surface W of the upper wafer W2 2 The bonding surface W between j and the lower wafer W1 1 The two wafers come into full contact, joining the lower wafer W1 and the upper wafer W2 to obtain a polymerized wafer T. The push pin 191 is then raised back to its original position.

[0065] Next, the moving unit 170 lowers the lower holding unit 110, increasing the vertical distance between the lower holding unit 110 and the upper holding unit 120. Then, the transport device 61 delivers the polymerized wafer T to the bonding device 41 (step S115). Specifically, first, the lower holding unit 110 releases the polymerized wafer T. Subsequently, the multiple holding pins 115 rise, passing the polymerized wafer T to the transport device 61. After that, the multiple holding pins 115 descend back to their original positions.

[0066] Next, with reference to Figures 8 to 11, an example of detecting the position of the lower alignment mark M12 and correcting the detected position will be described. As shown in Figure 8, the bonding apparatus 41 includes, for example, an upper imaging unit 150, an upper illumination unit 160, and an upper spectrometer 165 in order to detect the position of the lower alignment mark M12 and correct the detected position.

[0067] The upper imaging unit 150 images the lower wafer W1. The upper imaging unit 150 includes, for example, an objective lens 151, an imaging lens 152, and a light-receiving element 153. Although not shown, multiple light-receiving elements 153 are arranged in two dimensions. One light-receiving element 153 constitutes one pixel. The light-receiving element 153 receives reflected light from the lower wafer W1.

[0068] The upper imaging unit 150 may be either a monochrome camera or a color camera, but in this embodiment it is a monochrome camera. When the upper imaging unit 150 is a monochrome camera, one light-receiving element 153 receives light of various colors (light of various wavelengths), rather than light of a specific color (light of a specific wavelength), and generates an electrical signal according to the light reception intensity. The higher the light reception intensity, the higher the brightness of the pixel.

[0069] The upper imaging unit 150 may have a beam splitter 154, such as a half mirror, between the objective lens 151 and the imaging lens 152. The beam splitter 154 reflects the white light irradiated by the upper illumination unit 160 toward the lower wafer W1, and transmits the reflected light generated by the reflection of the white light from the lower wafer W1 toward the photodetector 153.

[0070] The upper illumination unit 160 is fixed to the upper holding unit 120, similar to the upper imaging unit 150, but it does not have to be fixed to the upper holding unit 120. When the upper imaging unit 150 is imaging the lower alignment mark M12, the upper illumination unit 160 illuminates the imaging area of ​​the upper imaging unit 150 with white light. The white light is illuminated to the imaging area of ​​the upper imaging unit 150 via the beam splitter 154. The beam splitter 154 is not required, and the white light may be directly illuminated to the imaging area of ​​the upper imaging unit 150.

[0071] The upper illumination unit 160 has a white light source 161. The light source 161 is, for example, a white LED. The light emission method of the white LED is not particularly limited. The white LED may include a blue LED and a yellow phosphor, or a red LED, a green LED and a blue LED, or a near-ultraviolet LED, a red phosphor, a green phosphor and a blue phosphor.

[0072] As shown in Figure 9, the upper imaging unit 150 captures an image P including the lower alignment mark M12 and its surroundings. The upper imaging unit 150 transmits the image P to the control unit 200. The control unit 200 has a position detection unit 201 (see Figure 11). The position detection unit 201 detects the position of the lower alignment mark M12 by processing the image P. For example, the position detection unit 201 detects the position where the change in brightness in the image P is maximum as the position of the lower alignment mark M12.

[0073] The difference in brightness (contrast) between the lower alignment mark M12 and its surroundings in image P is mainly determined by the difference in reflectivity between the lower alignment mark M12 and its surroundings. The greater the difference in reflectivity, the greater the difference in brightness. The difference in reflectivity is mainly determined by the film thickness and material of the film W1b on the lower wafer W1, and the thickness and material of the lower alignment mark M12.

[0074] Figure 10 shows an example of the reflection spectrum between the lower alignment mark M12 and its surroundings. The reflection spectra differ between the lower alignment mark M12 and its surroundings because the stacked structure of the lower wafer W1 is different. The difference in reflectivity between the lower alignment mark M12 and its surroundings increases or decreases depending on the wavelength of light.

[0075] Therefore, when the upper imaging unit 150 is imaging the lower alignment mark M12, the upper illumination unit 160 irradiates the imaging area of ​​the upper imaging unit 150 with white light containing light of various wavelengths, rather than light of a specific wavelength (for example, red light). As a result, even if the film thickness or material of the film W1b changes, a stable difference in reflectivity can be ensured between the lower alignment mark M12 and its surroundings, and a stable difference in brightness can be ensured in the image P.

[0076] The photodetector 153 of the upper imaging unit 150 receives light of various wavelengths. In this process, light of various wavelengths passes through the objective lens 151 and the imaging lens 152, etc. Consequently, chromatic aberration occurs. Chromatic aberration leads to a shift in the detection position of the lower alignment mark M12. If the amount of shift in the detection position (magnitude and direction) is constant, there is no problem. However, if the film thickness or material of the film W1b changes, the reflection spectrum changes, the effect of chromatic aberration changes, and the amount of shift in the detection position changes.

[0077] Therefore, the upper spectrometer 165 detects the reflection spectrum of the reflected light reflected from the lower wafer W1. The upper spectrometer 165 is fixed to the upper holding unit 120, similar to the upper imaging unit 150, but it does not have to be fixed to the upper holding unit 120. The upper spectrometer 165 has, for example, a white light source (not shown), similar to the upper irradiation unit 160, and irradiates the lower wafer W1 with white light emitted from the light source, and detects the reflection spectrum of the reflected light reflected from the lower wafer W1.

[0078] The upper spectrometer 165 primarily detects the reflection spectrum of reflected light reflected around the lower alignment mark M12. This is because the measurement area of ​​the upper spectrometer 165 is larger than the size of the lower alignment mark M12, making it difficult to obtain the reflection spectrum of reflected light reflected only from the lower alignment mark.

[0079] The upper spectrometer 165 transmits the detected results to the control unit 200. The control unit 200 has a reflection characteristic analysis unit 202 (see Figure 11). The reflection characteristic analysis unit 202 determines the relationship between the wavelength and intensity of the reflected light. The relationship to be determined includes, for example, the intensity ratio of a first color light and a second color light, which are different colors from each other. The first color light is, for example, red light, and the second color light is, for example, blue light. The relationship to be determined may also include the intensity ratio of the first color light, the second color light, and the third color light, which are different colors from each other. The third color light is, for example, green light. Changes in these intensity ratios represent changes in the effect of chromatic aberration and changes in the amount of shift in the detection position.

[0080] The control unit 200 includes a position correction unit 203. The position correction unit 203 corrects the position detected by the position detection unit 201 based on the relationship (such as the intensity ratio of the first color light and the second color light) determined by the reflection characteristic analysis unit 202. This ensures that the accurate position of the lower alignment mark M12 can be determined even if the effect of chromatic aberration changes due to changes in the film thickness or material of the film W1b. The relationship between the intensity ratio of the first color light and the second color light and the amount of correction (magnitude and direction) of the detected position is determined in advance through testing and stored in the storage medium of the control unit 200.

[0081] The control unit 200 includes a movement control unit 204. The movement control unit 204 controls the movement unit 170 based on the position of the lower alignment mark M12 corrected by the position correction unit 203. The movement control unit 204 controls the movement unit 170 so that the lower alignment mark M12 and the upper alignment mark M22 overlap when viewed in the vertical direction. This improves the alignment accuracy before joining.

[0082] Although not shown in the figures, the bonding apparatus 41 may include, for example, a lower imaging unit 130, a lower illumination unit, and a lower spectrometer to detect the position of the upper alignment mark M22 and correct the detected position. The lower illumination unit irradiates the imaging area of ​​the lower imaging unit 130 with white light when the upper alignment mark M22 is being imaged by the lower imaging unit 130. The lower illumination unit is fixed to the lower holding unit 110 in the same way as the lower imaging unit 130, but it does not have to be fixed to the lower holding unit 110. The lower spectrometer detects the reflection spectrum of the reflected light reflected from the upper wafer W2 and transmits the detected result to the control unit 200. The lower spectrometer is fixed to the lower holding unit 110 in the same way as the lower imaging unit 130, but it does not have to be fixed to the lower holding unit 110.

[0083] The reflection characteristic analysis unit 202 determines the relationship between the wavelength and intensity of the reflected light reflected from the upper wafer W2. The position correction unit 203 corrects the position of the upper alignment mark M22 detected by the position detection unit 201 based on the relationship (such as the intensity ratio of the first color light and the second color light) determined by the reflection characteristic analysis unit 202. The movement control unit 204 controls the movement unit 170 based on the position of the upper alignment mark M22 corrected by the position correction unit 203.

[0084] Next, with reference to Figure 12, a first modified example of the upper imaging unit 150 and the upper illumination unit 160 will be described. The differences will be mainly explained below. As shown in Figure 12, the bonding apparatus 41 includes an upper imaging unit 150 and an upper illumination unit 160, but does not include the upper spectrometer 165 shown in Figure 8. The reflection characteristic analysis unit 202 uses the upper imaging unit 150 instead of the upper spectrometer 165 to determine the relationship between the wavelength and intensity of the reflected light reflected from the lower wafer W1.

[0085] The upper imaging unit 150 is a color camera. The color camera includes a first-color light-receiving element 153A, a second-color light-receiving element 153B, and a third-color light-receiving element 153C. The first-color light-receiving element 153A, the second-color light-receiving element 153B, and the third-color light-receiving element 153C receive light that has passed through different color filters and receive light of different colors. One pixel is composed of the first-color light-receiving element 153A, the second-color light-receiving element 153B, and the third-color light-receiving element 153C. Although not shown in the diagram, multiple pixels are arranged in a two-dimensional manner.

[0086] The reflection characteristic analysis unit 202 determines the ratio of the light received intensities of the first-color photodetector 153A and the second-color photodetector 153B that constitute the same pixel. The first color is, for example, red, and the second color is, for example, blue. The reflection characteristic analysis unit 202 may also determine the ratio of the light received intensities of the first-color photodetector 153A, the second-color photodetector 153B, and the third-color photodetector 153C that constitute the same pixel. The third color is, for example, green light. These ratios of light received intensities represent the relationship between the wavelength and intensity of the reflected light.

[0087] The size of the imaging area of ​​a single pixel is sufficiently small compared to the size of the lower alignment mark M12. Therefore, it is possible to determine the ratio of light reception intensity separately for the lower alignment mark M12 and its surroundings.

[0088] The pixels used to determine the ratio of received light intensity may be either pixels that image the area around the lower alignment mark M12, pixels that image the lower alignment mark M12, or both. Multiple pixels may be used to determine the ratio of either of the received light intensity. In other words, the ratio of received light intensity may be an average value.

[0089] The details of this modified example can also be applied to the lower imaging unit 130 and the lower illumination unit. In other words, if the lower imaging unit 130 is a color camera, the reflection characteristic analysis unit 202 can use the lower imaging unit 130 instead of the lower spectrometer to determine the relationship between the wavelength and intensity of the reflected light reflected from the upper wafer W2.

[0090] Next, with reference to Figure 13, a second modified example of the upper imaging unit 150 and the upper illumination unit 160 will be described. The differences will be mainly explained below. Even if the upper imaging unit 150 is a monochrome camera, if the upper illumination unit 160 can switch between illuminating the imaging area of ​​the upper imaging unit 150 with white light, first-color light, and second-color light, which are different colors from each other, then the upper spectrometer 165 is unnecessary. The reflection characteristic analysis unit 202 uses the upper imaging unit 150 instead of the upper spectrometer 165 to determine the relationship between the wavelength and intensity of the reflected light reflected from the lower wafer W1.

[0091] The upper illumination unit 160 includes, for example, a white light source 161, a first color filter 162A, and a second color filter 162B. The first color filter 162A selectively transmits the first color of white light. The second color filter 162B selectively transmits the second color of white light. The first color of white light is, for example, red light, and the second color of white light is, for example, blue light.

[0092] The first color filter 162A and the second color filter 162B are moved between a position in the middle of the white light optical path and a position outside the white light optical path, respectively. This allows the upper illumination unit 160 to switch between illuminating the imaging area of ​​the upper imaging unit 150 with white light, first color light, and second color light, which are of different colors.

[0093] The upper illumination unit 160 may further include a third-color filter 162C. The third-color filter 162C selectively transmits third-color light from white light. The third-color light is, for example, green light. The third-color filter 162C can be moved between a position in the middle of the optical path of white light and a position outside the optical path of white light. This allows the upper illumination unit 160 to switch between illuminating the imaging area of ​​the upper imaging unit 150 with white light, first-color light, second-color light, and third-color light, which are all different colors from each other.

[0094] The reflection characteristic analysis unit 202 determines the ratio of the light received by the same photodetector 153 when the imaging area of ​​the upper imaging unit 150 is fixed and the first color light and the second color light are switched and irradiated. The first color is, for example, red, and the second color is, for example, blue. The reflection characteristic analysis unit 202 may also include the ratio of the light received by the same photodetector 153 when the imaging area of ​​the upper imaging unit 150 is fixed and the first color light, the second color light, and the third color light are switched and irradiated. The third color is, for example, green light. These ratios of light received intensities represent the relationship between the wavelength and intensity of the reflected light.

[0095] The size of the imaging area of ​​a single pixel is sufficiently small compared to the size of the lower alignment mark M12. Therefore, it is possible to determine the ratio of light reception intensity separately for the lower alignment mark M12 and its surroundings.

[0096] The pixels used to determine the ratio of received light intensity may be either pixels that image the area around the lower alignment mark M12, pixels that image the lower alignment mark M12, or both. Multiple pixels may be used to determine the ratio of either of the received light intensity. In other words, the ratio of received light intensity may be an average value.

[0097] The details of this modified configuration are also applicable to the lower imaging unit 130 and the lower illumination unit. Even if the lower imaging unit 130 is a monochrome camera, a lower spectrometer is unnecessary if the lower illumination unit can switch between illuminating the imaging area of ​​the lower imaging unit 130 with white light, a first-color light, and a second-color light, which are of different colors. The lower illumination unit may have a white light source, a first-color filter, and a second-color filter. The lower illumination unit may further have a third-color filter.

[0098] Next, with reference to Figure 14, a third modified example of the upper imaging unit 150 and the upper illumination unit 160 will be described. The differences will be mainly explained below. The white light source 161 emits white light, first color light, and second color light, which are of different colors, to the imaging area of ​​the upper imaging unit 150. Third-color light and To switch between emitting light, the system may have a first-color light source 161A, a second-color light source 161B, and a third-color light source 161C.

[0099] The first color of light is, for example, red light; the second color of light is, for example, blue light; and the third color of light is, for example, green light. The upper illumination unit 160 can emit white light by simultaneously lighting the three light sources 161A, 161B, and 161C. Alternatively, the upper illumination unit 160 can emit only one of the first, second, or third color of light by lighting only one of the three light sources 161A, 161B, or 161C.

[0100] The white light source 161 includes a first-color light source 161A, a second-color light source 161B, and a third-color light source 161C, but the technology of this disclosure is not limited thereto. The upper illumination unit 160 may have the white light source 161, the first-color light source 161A, the second-color light source 161B, and the third-color light source 161C separately.

[0101] The details of this modification can also be applied to the lower imaging unit 130 and the lower illumination unit. That is, the lower illumination unit may have a white light source, and the white light source may have a first-color light source, a second-color light source, and a third-color light source. Alternatively, the lower illumination unit may have a white light source, a first-color light source, a second-color light source, and a third-color light source separately.

[0102] While embodiments of the joining apparatus and joining method relating to this disclosure have been described above, this disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These also naturally fall within the technical scope of this disclosure. [Explanation of Symbols]

[0103] 1. Joining System 41 Joining equipment 110 Lower holding part (first holding part) 120 Upper holding part (second holding part) 130 Lower imaging unit (first imaging unit) 150 Upper imaging unit (second imaging unit) 160 Upper irradiation section (second irradiation section) 170 Mobile Unit 200 Control Unit W1 Lower wafer (first substrate) W2 Upper wafer (second substrate)

Claims

1. A bonding apparatus for bonding a first substrate including a first alignment mark and a second substrate including a second alignment mark, A first holding portion that holds the first substrate, A second holding portion that holds the second substrate, A first imaging unit is provided in the first holding unit and images the second substrate which is held in the second holding unit, A first illumination unit that illuminates the imaging area of ​​the first imaging unit with white light when the first imaging unit is imaging the second alignment mark, A second imaging unit is provided in the second holding unit and images the first substrate held in the first holding unit, A second illumination unit that illuminates the imaging area of ​​the second imaging unit with white light when the second imaging unit is imaging the first alignment mark, A moving part that moves the first holding part and the second holding part relative to each other, A control unit that controls the moving part, Equipped with, The control unit processes the images captured by the first imaging unit and the second imaging unit to detect the positions of the first and second alignment marks, corrects the detected position of the first alignment mark based on the relationship between the wavelength and intensity of the reflected light reflected by the first substrate, and controls the moving unit based on the corrected position of the first alignment mark. The second imaging unit has a color camera, and the color camera includes a first color light-receiving element and a second color light-receiving element that receive light of different colors from each other. The control unit corrects the position of the first alignment mark based on the ratio of the light-receiving intensity of the first color light-receiving element and the second color light-receiving element that constitute the same pixel, and is a bonding device.

2. A bonding apparatus for bonding a first substrate including a first alignment mark and a second substrate including a second alignment mark, A first holding portion that holds the first substrate, A second holding portion that holds the second substrate, A first imaging unit is provided in the first holding unit and images the second substrate which is held in the second holding unit, A first illumination unit that illuminates the imaging area of ​​the first imaging unit with white light when the first imaging unit is imaging the second alignment mark, A second imaging unit is provided in the second holding unit and images the first substrate held in the first holding unit, A second illumination unit that illuminates the imaging area of ​​the second imaging unit with white light when the second imaging unit is imaging the first alignment mark, A moving part that moves the first holding part and the second holding part relative to each other, A control unit that controls the moving part, Equipped with, The control unit processes the images captured by the first imaging unit and the second imaging unit to detect the positions of the first and second alignment marks, corrects the detected position of the first alignment mark based on the relationship between the wavelength and intensity of the reflected light reflected by the first substrate, and controls the moving unit based on the corrected position of the first alignment mark. The second irradiation unit irradiates the imaging area of ​​the second imaging unit with white light, first color light, and second color light, which are of different colors, by switching between them. The second imaging unit has a monochrome camera, and the monochrome camera includes a light-receiving element. The control unit corrects the position of the first alignment mark based on the ratio of the light reception intensity of the same light receiving element when the imaging area of ​​the second imaging unit is fixed and the first color light and the second color light are switched and irradiated.

3. The bonding apparatus according to claim 2, wherein the second irradiation unit comprises a first color filter that selectively transmits the first color light from the white light, and a second color filter that selectively transmits the second color light from the white light.

4. The bonding apparatus according to claim 2, wherein the second irradiation unit has the white light source and the white light source has the first color light source and the second color light source, or the second irradiation unit separately has the white light source, the first color light source and the second color light source.

5. A bonding apparatus for bonding a first substrate including a first alignment mark and a second substrate including a second alignment mark, A first holding portion that holds the first substrate, A second holding portion that holds the second substrate, A first imaging unit is provided in the first holding unit and images the second substrate which is held in the second holding unit, A first illumination unit that illuminates the imaging area of ​​the first imaging unit with white light when the first imaging unit is imaging the second alignment mark, A second imaging unit is provided in the second holding unit and images the first substrate held in the first holding unit, A second illumination unit that illuminates the imaging area of ​​the second imaging unit with white light when the second imaging unit is imaging the first alignment mark, A moving part that moves the first holding part and the second holding part relative to each other, A control unit that controls the moving part, Equipped with, The control unit processes the images captured by the first imaging unit and the second imaging unit to detect the positions of the first and second alignment marks, corrects the detected position of the first alignment mark based on the relationship between the wavelength and intensity of the reflected light reflected by the first substrate, and controls the moving unit based on the corrected position of the first alignment mark. The system includes a spectrometer for detecting the intensity of reflected light at two or more wavelengths reflected by the first substrate, The control unit corrects the position of the first alignment mark based on the intensity ratio of reflected light at two or more wavelengths detected by the spectrometer, in a bonding apparatus.

6. A bonding method comprising bonding a first substrate including a first alignment mark and a second substrate including a second alignment mark, The first substrate is held by the first holding part, The second substrate is held by the second holding part, The first imaging unit provided in the first holding unit images the second substrate held in the second holding unit, When the first imaging unit captures the second alignment mark, white light is irradiated from the first illumination unit to the imaging area of ​​the first imaging unit, The second imaging unit provided in the second holding unit captures the first substrate held in the first holding unit, When the second imaging unit captures the first alignment mark, white light is irradiated from the second illumination unit onto the imaging area of ​​the second imaging unit. The positions of the first alignment mark and the second alignment mark are detected by processing the images captured by the first imaging unit and the second imaging unit. The position of the detected first alignment mark is corrected based on the relationship between the wavelength and intensity of the reflected light reflected by the first substrate, Based on the corrected position of the first alignment mark, the first holding part and the second holding part are moved relative to each other. It has, The second imaging unit has a color camera, and the color camera includes a first color light-receiving element and a second color light-receiving element that receive light of different colors from each other. The bonding method comprises correcting the position of the first alignment mark based on the ratio of the light-receiving intensity of the first color light-receiving element and the second color light-receiving element that constitute the same pixel.

7. A bonding method comprising bonding a first substrate including a first alignment mark and a second substrate including a second alignment mark, The first substrate is held by the first holding part, The second substrate is held by the second holding part, The first imaging unit provided in the first holding unit images the second substrate held in the second holding unit, When the first imaging unit captures the second alignment mark, white light is irradiated from the first illumination unit to the imaging area of ​​the first imaging unit, The second imaging unit provided in the second holding unit captures the first substrate held in the first holding unit, When the second imaging unit captures the first alignment mark, white light is irradiated from the second illumination unit onto the imaging area of ​​the second imaging unit. The positions of the first alignment mark and the second alignment mark are detected by processing the images captured by the first imaging unit and the second imaging unit. The position of the detected first alignment mark is corrected based on the relationship between the wavelength and intensity of the reflected light reflected by the first substrate, Based on the corrected position of the first alignment mark, the first holding part and the second holding part are moved relative to each other. It has, The second irradiation unit irradiates the imaging area of ​​the second imaging unit with white light, first color light, and second color light, which are of different colors, by switching between them. The second imaging unit has a monochrome camera, and the monochrome camera includes a light-receiving element. The bonding method comprises correcting the position of the first alignment mark based on the ratio of the light reception intensity of the same photodetector when the imaging area of ​​the second imaging unit is fixed and the first color light and the second color light are switched and irradiated.

8. The bonding method according to claim 7, wherein the second irradiation unit comprises a first color filter that selectively transmits the first color light from the white light, and a second color filter that selectively transmits the second color light from the white light.

9. The bonding method according to claim 7, wherein the second irradiation unit has the white light source and the white light source has the first color light source and the second color light source, or the second irradiation unit has the white light source, the first color light source and the second color light source separately.

10. A bonding method comprising bonding a first substrate including a first alignment mark and a second substrate including a second alignment mark, The first substrate is held by the first holding part, The second substrate is held by the second holding part, The first imaging unit provided in the first holding unit images the second substrate held in the second holding unit, When the first imaging unit captures the second alignment mark, white light is irradiated from the first illumination unit to the imaging area of ​​the first imaging unit, The second imaging unit provided in the second holding unit captures the first substrate held in the first holding unit, When the second imaging unit captures the first alignment mark, white light is irradiated from the second illumination unit onto the imaging area of ​​the second imaging unit. The positions of the first alignment mark and the second alignment mark are detected by processing the images captured by the first imaging unit and the second imaging unit. The position of the detected first alignment mark is corrected based on the relationship between the wavelength and intensity of the reflected light reflected by the first substrate, Based on the corrected position of the first alignment mark, the first holding part and the second holding part are moved relative to each other. It has, A bonding method comprising: detecting the intensity of reflected light at two or more wavelengths reflected by the first substrate using a spectrometer; and correcting the position of the first alignment mark based on the intensity ratio of the reflected light at two or more wavelengths detected by the spectrometer.

Images