Bonding apparatus and bonding method

Abstract

To shorten a time until substrates are bonded to each other when the substrates are bonded to each other.SOLUTION: A bonding device 1 for bonding substrates to each other includes a control unit 210 for controlling the bonding device 1. The control unit 210 includes a first imaging control unit 211 configured to image, by the first imaging unit 70, the first alignment mark W1 on the first substrate W1 before the first substrate M1 is held by the first holder 105 and / or the second alignment mark W2 on the second substrate W2 before the second substrate M2 is held by the second holder 110, and a second imaging control unit 212 configured to image, by the second imaging unit 120 capable of imaging at a higher magnification than the first imaging unit 70, the first alignment mark W1 on the first substrate M1 and the second alignment mark W2 on the second substrate respectively held by the first holder 105 and the second holder 110 disposed to face each other. M2.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a bonding apparatus and a bonding method for bonding substrates together. [Background technology]

[0002] Conventionally, there are known techniques for bonding substrates such as semiconductor wafers and glass substrates. For example, Patent Document 1 discloses a wafer forming method in which a silicon substrate and a support member are bonded together via an oxide film by room temperature bonding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-4799 Summary of the Invention [Problem to be solved by the invention]

[0004] In bonding such substrates, the substrates are aligned with each other while facing each other, and then the substrates are bonded together. The alignment of the substrates is performed by roughly aligning the substrates while capturing images of marks formed on the substrates with a low-magnification macro camera, and then switching to a high-magnification micro camera for precise alignment. In this case, the substrates are bonded after being aligned with each other, and then roughly and precisely aligned, which poses a problem: it takes time to bond the substrates from an opposing state.

[0005] The present invention provides a bonding apparatus and a bonding method that can shorten the time required to bond substrates together when bonding substrates together. [Means for solving the problem]

[0006] One aspect of the present invention is A bonding device for bonding a first substrate and a second substrate, a first holding part that holds the first substrate; a second holding section disposed opposite the first holding section and configured to hold the second substrate to be bonded to the first substrate; a first imaging unit capable of capturing images of a first alignment mark formed on the first substrate and a second alignment mark formed on the second substrate; a second imaging unit having a first imaging section that images the first alignment mark formed on the first substrate and a second imaging section that images the second alignment mark formed on the second substrate, and capable of imaging at a higher magnification than the first imaging unit; a moving unit that moves the second imaging unit, the first holding unit, and the second holding unit relatively in a region between the first holding unit and the second holding unit; a control unit that controls the joining device, The control unit a first imaging control unit that uses the first imaging unit to capture an image of the first alignment mark before the first holding unit holds the first substrate and / or the second alignment mark before the second holding unit holds the second substrate; and a second imaging control unit that uses the second imaging unit to capture an image of the first alignment mark of the first substrate held by the first holding unit and the second alignment mark of the second substrate held by the second holding unit.

[0007] Another aspect of the present invention is A bonding method for bonding a first substrate and a second substrate, comprising: a first imaging step of imaging, with a first imaging unit, a first alignment mark formed on the first substrate and / or a second alignment mark formed on the second substrate bonded to the first substrate; a first holding step of holding the first substrate by a first holding unit after the first imaging step; a second holding step of holding the second substrate by a second holding part disposed opposite to the first holding part after the first imaging step; a first positioning step of positioning a second imaging unit having a first imaging section that images the first alignment mark of the first substrate held by the first holding section and a second imaging section that images the second alignment mark of the second substrate held by the second holding section in a region between the first holding section and the second holding section so that the first imaging section images the first alignment mark; a second imaging step of imaging the first alignment mark using the first imaging unit after the first positioning step; a second positioning step of positioning the second imaging unit in the region between the first holding part and the second holding part so as to image the second alignment mark with the second imaging part; a third imaging step of imaging the second alignment mark using the second imaging unit after the second positioning step; a retracting step of retracting the second imaging unit positioned in the region between the first holding part and the second holding part; a bonding step of bonding the first substrate held by the first holding unit and the second substrate held by the second holding unit after the retracting step, The first imaging step is performed at a lower magnification than the second imaging step and the third imaging step. [Effects of the Invention]

[0008] According to the present invention, when bonding substrates together, the time required to bond the substrates together can be reduced. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an example of a first substrate W1 and a second substrate W2. [Figure 2] FIG. 2 is a diagram for explaining the bonding of the first substrate W1 and the second substrate W2. [Figure 3] FIG. 3 is a perspective view showing an example of the joining device 1. As shown in FIG. [Figure 4]FIG. 4 is a diagram illustrating an example of the joining unit 100. As shown in FIG. [Figure 5] FIG. 5 is a diagram for explaining the first imaging unit 121 and the second imaging unit 122 in the embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of the joining method process. [Figure 7] FIG. 7 is a diagram for explaining the first imaging step S10. [Figure 8] FIG. 8 is a diagram for explaining the first holding step S11 and the second holding step S12. [Figure 9] FIG. 9 is a diagram for explaining the first positioning step S13 and the second positioning step S15. [Figure 10] FIG. 10 is a diagram for explaining the second imaging step S14 and the third imaging step S16. [Figure 11] FIG. 11 is a diagram for explaining the retraction step S18. [Figure 12] FIG. 12 is a diagram for explaining the joining step S19. [Figure 13] FIG. 13 is a perspective view showing an example of the bonded substrate W3. [Figure 14] FIG. 14 is a diagram for explaining another example of the first imaging section 121 and the second imaging section 122. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus and a method for bonding substrates according to an embodiment of the present invention will be described below with reference to the drawings.

[0011] First, before describing the bonding apparatus 1 and the bonding method, we will describe the substrate W used in the bonding apparatus 1 and the bonding method. The substrate W is a wafer made of, for example, Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or other semiconductor material.

[0012] Fig. 1 is a perspective view showing an example of the substrate W. Fig. 1(a) shows a first substrate W1, which is an example of one of the substrates to be joined, and Fig. 1(b) shows a second substrate W2, which is an example of the other of the substrates to be joined.

[0013] In the following description, the first substrate will be referred to as "W1", the second substrate will be referred to as "W2", the bonded substrate formed by bonding the first substrate W1 and the second substrate W2 will be referred to as "W3", and when there is no need to distinguish between the first substrate W1, the second substrate, and the bonded substrate W3, the symbol will simply be "W".

[0014] The first substrate W1 has a front surface 11 and a back surface 12 that are generally parallel to each other. As shown in Fig. 1(a), the front surface 11 of the first substrate W1 has a plurality of areas partitioned by a plurality of mutually intersecting streets 13 that serve as division lines, and these areas are formed in a grid pattern. Devices 14, such as ICs (Integrated Circuits), LSIs (Large Scale Integrated circuits), and MEMS (Micro Electro Mechanical Systems), are formed in each of the partitioned areas.

[0015] The first substrate W1 is also formed with a first alignment mark M1. The first alignment mark M1 serves as a mark for alignment when bonding the first substrate W1 and the second substrate W2 together, and is formed, for example, on the outer periphery of the first substrate W1 where no devices 14 are formed. Reference numeral 15 denotes a notch that indicates the crystal orientation of the first substrate W1.

[0016] The second substrate W2 may have the same configuration as the first substrate W1. That is, the second substrate W2 also has a front surface 21 and a back surface 22 that are generally parallel to each other. As shown in FIG. 1(b), the front surface 21 of the second substrate W2 has a plurality of intersecting streets 23 that serve as planned division lines, and a plurality of regions partitioned by these planned division lines are formed in a lattice pattern. Devices 24 such as ICs, LSIs, and MEMS are formed in each of the partitioned regions. Note that reference numeral 25 denotes a notch that indicates the crystal orientation of the second substrate W2.

[0017] In addition, second alignment marks M2 are formed on the second substrate W2. The second alignment marks M2 serve as marks for alignment when bonding the second substrate W2 and the first substrate W1, and are formed, for example, on the outer periphery of the second substrate W2 where no devices 24 are formed, and are formed in the same position as the first alignment marks M1. In the following description, when there is no need to distinguish between the first alignment marks M1 and the second alignment marks M2, they will simply be referred to as "alignment marks M."

[0018] Furthermore, on each of the surface 11 side of the first substrate W1 and the surface 21 side of the second substrate W2, a laminate including various patterned thin films (none of which are shown) such as conductive films that function as electrodes, wiring, terminals, etc., and insulating films that function as interlayer insulating films, etc. is formed.

[0019] The surface 11 of the first substrate W1 and the surface 21 of the second substrate W2 thus configured are placed opposite each other, and the substrates are bonded together using a bonding device 1 (see FIG. 2). As a result, a bonded substrate W3 (see FIG. 13) is formed by bonding the first substrate W1 and the second substrate W2 together.

[0020] The devices 14 on the first substrate W1 and the devices 24 on the second substrate W2 each have an electrode pad and a through electrode connected to the electrode pad, and the through electrode enables connection of the electrodes when the substrates are bonded together. In other words, the first substrate W1 and the second substrate W2 are substrates in which the devices have through electrodes (TSV: Through Silicon Via).

[0021] (Joining equipment) Next, the joining device 1 will be described. Fig. 3 shows a schematic diagram of an example of the joining device 1. In the following description, the X-axis direction is one direction on a horizontal plane. The Y-axis direction is a direction on a horizontal plane that is perpendicular to the X-axis direction. The Z-axis direction is a direction that is perpendicular to the X-axis and Y-axis directions.

[0022] The bonding apparatus 1 includes, as main components, a base 30, a cassette storage section 40, a transport unit 50, a temporary placement table 60, a bonding unit 100, and a control unit 200.

[0023] The cassette housing section 40 is provided on one end side of the base 30 in the X-axis direction and includes two housing spaces, a first housing space 40a and a second housing space 40b, aligned in the Y-axis direction. For example, a cassette C1 that houses a first substrate W1 and a second substrate W2 before being bonded is placed in the first housing space 40a. For example, a cassette C2 that houses a bonded substrate W3 after being bonded is placed in the second housing space 40b. Cassettes C1 and C2 can each house multiple substrates W.

[0024] The transport unit 50 is provided adjacent to the cassette storage section 40 and loads and unloads substrates W into and from each of the cassettes C1 and C2. The transport unit 50 includes a base 51 and a rotatable arm 52 supported on the base 51. The base 51 is configured to be movable, for example, in the X-axis direction and the Y-axis direction. The movable direction of the base 51 may be any direction as long as the substrate W can be loaded and unloaded by the movement of the base 51 and the operation of the arm 52. Furthermore, if the substrate W can be loaded and unloaded by the operation of the arm 52 alone, the base 51 may not be configured to move. In this embodiment, the transport unit 50 is capable of moving in the X-axis direction and the Y-axis direction by a known movement mechanism (not shown) configured, for example, by a guide rail, a ball screw, a pulse motor, etc.

[0025] The transport unit 50 transports the substrate W between the cassette accommodation section 40, the temporary placement table 60, and the bonding unit 100 by moving the base 51 and operating the arm 52. Specifically, the transport unit 50 takes out the first substrate W1 and the second substrate W2 before bonding from the cassette C1 and loads them onto the temporary placement table 60. Then, after a predetermined process has been performed on the temporary placement table 60, the transport unit 50 takes out the substrate W from the temporary placement table 60 and loads it into the bonding unit 100. The transport unit 50 also takes out the bonded substrate W3 produced in the bonding unit 100 from the bonding unit 100 and loads it into the cassette C2 in the second accommodation space 40b.

[0026] The temporary placement table 60 sucks and holds the transported first substrate W1 and second substrate W2 by operating a suction source (not shown). The temporary placement table 60 is also provided with a first imaging unit 70 for detecting alignment marks M formed on the substrate W, the center position of the substrate W, and the like.

[0027] The first imaging unit 70 detects the alignment marks M on the first substrate W1 and the second substrate W2 before they are bonded, the center position of the substrate W, and the like, using the captured images. The first imaging unit 70 has, for example, a wide-area objective lens 71, which is a wide-area macro lens, as a lens for capturing an image of the substrate W including the alignment marks M. The imaging data captured by the first imaging unit 70 is output to the control unit 200.

[0028] The first imaging unit 70 can capture images of the first substrate W1 including the first alignment mark M1 and the second substrate W2 including the second alignment mark M2 over a relatively wide range by using the wide-area objective lens 71. Furthermore, the first imaging unit 70 can adjust the focus of the wide-area objective lens 71 to the substrate W to be imaged.

[0029] The bonding unit 100 includes a chamber 102 capable of forming a sealed processing space therein, and accommodates the first substrate W1 and the second substrate W2 transported by the transport unit 50 in this chamber 102, and then reduces the pressure inside the chamber 102. The bonding unit 100 then bonds the first substrate W1 and the second substrate W2 inside the decompressed chamber 102.

[0030] 4 is a diagram schematically illustrating an example of the bonding unit 100. Specifically, the bonding unit 100 includes a first holding part 105 that holds the first substrate W1, a second holding part 110 that holds the second substrate W2, a second imaging unit 120 that captures images of the first alignment mark M1 provided on the first substrate W1 and the second alignment mark M2 provided on the second substrate W2, and a moving unit 130 that moves the second imaging unit 120.

[0031] The first holding unit 105 is a holding unit that suction-holds the first substrate W1, and is provided opposite the second holding unit 110. It is supported so that it can be raised and lowered in the vertical direction (Z-axis direction) with its holding surface facing downward. The first substrate W1 is held by the first holding unit 105 with its bonding surface with the second substrate W2 (i.e., front surface 11) facing downward. The lower surface of the first holding unit is a holding surface made of, for example, porous ceramic, and suction-holds the first substrate W1 by operating a suction source (not shown).

[0032] Moreover, an adjustment unit 106 is provided above the first holding unit 105 to adjust the horizontal position of the first holding unit 105. The adjustment unit 106 can move the first holding unit 105 in the X-axis direction or the Y-axis direction. The adjustment unit 106 can also rotate the first holding unit 105 around the Z-axis.

[0033] Furthermore, a through-hole penetrating the chamber 102 in the Z-axis direction is formed above the adjustment unit 106, and a shaft 107 is inserted into the through-hole. The shaft 107 can be raised and lowered in the vertical direction together with the first holding unit 105 and the adjustment unit 106, for example, by an elevation mechanism (not shown). As the shaft 107 is raised and lowered, the first holding unit 105 and the second holding unit 110 move closer to or farther apart. A cylindrical bellows joint 108 is provided around the through-hole so as to surround the through-hole.

[0034] The second holding part 110 is a holding part that adsorbs and holds the second substrate W2, and is arranged opposite the first holding part 105, and is supported below the chamber 102 with the bonding surface with the first substrate W1 (i.e., surface 21) facing upward.

[0035] In the embodiment, the above-described adjustment unit 106 is provided on the first holding unit 105 side, but this adjustment unit 106 may be provided on the second holding unit 110 side. Also, in the embodiment, the first holding unit 105 and the second holding unit 110 are configured to move closer to or farther away from each other by rising and falling together with the shaft 107, but the second holding unit 110 may be configured to move closer to or farther away from the first holding unit by rising and falling.

[0036] The second imaging unit 120 captures images of the first alignment mark M1 provided on the first substrate W1 and the second alignment mark M2 provided on the second substrate W2. The second imaging unit 120 has a first imaging section 121 that captures an image of the first alignment mark M1 and a second imaging section 122 that captures an image of the second alignment mark M2.

[0037] As shown in FIG. 5, the first imaging unit 121 has a first local objective lens 121a, which is a microlens capable of capturing high-resolution images, as a lens for capturing an image of the first alignment mark M1 formed on the first substrate W1.

[0038] By using the first local objective lens 121a, the first imaging section 121 can image the first alignment mark M1 on the first substrate W1 with higher resolution than when the image is captured by, for example, the above-described first imaging unit 70. Note that the first imaging section 121 can adjust the focus of the first local objective lens 121a to the first substrate W1.

[0039] Similarly, as shown in FIG. 5, the second imaging unit 122 has a second local objective lens 122a, which is a microlens capable of high-resolution imaging, as a lens for imaging the second alignment mark M2 formed on the second substrate W2.

[0040] By using the second local objective lens 122a, the second imaging section 122 can image the second alignment mark M2 of the second substrate W2 with higher resolution than when the second alignment mark M2 is imaged by, for example, the above-mentioned first imaging unit 70. Note that the second imaging section 122 can adjust the focus of the second local objective lens 122a to the second substrate W2.

[0041] The first imaging section 121 is attached to a moving unit 130 (described later) with the first local objective lens 121a facing upward. The second imaging section 122 is attached to a moving unit 130 (described later) with the second local objective lens 122a facing downward.

[0042] In this embodiment, the arrangement of the first local objective lens 121a and the second local objective lens 122a (hereinafter also collectively referred to as "the lenses") attached to the moving unit 130 is, for example, as shown in Fig. 5. Fig. 5(a) shows the arrangement of the lenses when the second imaging unit 120 is viewed from above, and Fig. 5(b) shows the arrangement of the lenses when the second imaging unit 120 is viewed from the side.

[0043] Each lens is attached to the moving unit 130 so as to image the first substrate W1 located above the lens or the second substrate W2 located below the lens, and the optical axis of each lens extends in the vertical direction. In the embodiment, as an example, the lenses are arranged in parallel on the same plane in the Y-axis direction, as shown in FIG.

[0044] More specifically, the first local objective lens 121a and the second local objective lens 122a are arranged in parallel, so that the optical axis of the first local objective lens 121a and the optical axis of the second local objective lens 122a are not arranged on the same straight line.

[0045] In the example shown in FIG. 5(a), the first local objective lens 121a is arranged on the left side of the paper and the second local objective lens 122a is arranged on the right side of the paper, but the arrangement may be reversed.

[0046] In this way, the first local objective lens 121a and the second local objective lens 122a are arranged in parallel on the same plane, so that their optical axes are not collinear in the vertical direction. In other words, the lenses are not arranged so as to overlap each other in the vertical direction. This allows the distance between the opposing first holding unit 105 and second holding unit 110 to be shorter than in a configuration in which, for example, the optical axis of the upward-facing objective lens that images the first substrate W1 and the optical axis of the downward-facing objective lens that images the second substrate W2 are arranged collinear in the vertical direction. As a result, the distance between the first substrate W1 and the second substrate W2 can be shortened. Furthermore, by shortening the distance between the substrates in this way, it is possible to prevent misalignment between the first substrate W1 and the second substrate W2 when the substrates are bonded together.

[0047] Returning to Fig. 4, the moving unit 130 will be described. The moving unit 130 moves the second imaging unit 120 in the planar area between the first holding part 105 and the second holding part 110, i.e., along the X-axis direction and the Y-axis direction. The moving unit 130 may have various configurations, and may be, for example, a known ball-screw type moving unit.

[0048] The first imaging section 121 and the second imaging section 122 are attached to one end of the moving unit 130, that is, the moving unit 130 can integrally move the first imaging section 121 and the second imaging section 122. Furthermore, the moving unit 130 moves, for example, along the Y-axis direction to move the second imaging unit 120 between an imaging position between the first holding section 105 and the second holding section 110 and a retracted position that is a position away from the imaging position between the first holding section 105 and the second holding section 110.

[0049] In this way, since the moving unit 130 is movable in the X-axis direction and the Y-axis direction, even if the first alignment mark M1 or the second alignment mark M2 is formed on the outer periphery of the substrate as in the embodiment, or on the inner periphery of the substrate, it is possible to image the alignment mark M by moving the moving unit 130 to the position where the alignment mark M is formed.

[0050] Furthermore, since the moving unit 130 can move the first imaging section 121 and the second imaging section 122 together, when imaging the first alignment mark M1 and the second alignment mark M2, it is possible to move to the imaging position and perform the imaging operation simultaneously.

[0051] An exhaust pipe for drawing air into the chamber 102 is connected to the chamber 102, and the exhaust pipe is connected to an exhaust device such as a vacuum pump (neither is shown).

[0052] The control unit 200 controls each of the above-mentioned components of the bonding apparatus 1 and causes the bonding apparatus 1 to perform various processes. The control unit 200 is a computer including a control unit 210 that performs various calculations, a storage unit having a storage medium, and an input / output interface (not shown) that controls input and output of data to and from the inside and outside of the control unit 200. The control unit 210 includes a microprocessor such as a CPU (Central Processing Unit). The storage unit has memories such as an HDD (Hard Disk Drive), ROM (Read Only Memory), or RAM (Random Access Memory). The control unit 210 performs various calculations based on predetermined programs stored in the storage unit. The control unit 210 outputs various control signals to each of the above-mentioned components via the input / output interface according to the calculation results, thereby controlling the bonding apparatus 1.

[0053] The storage unit stores in advance, for example, correction values ​​(in other words, misalignment amounts) for aligning the center of the temporary placement table 60 with the centers of the first holding unit 105 and the second holding unit 110. These correction values ​​are used when aligning the first substrate W1 and the second substrate W2 in the chamber 102, which will be described later.

[0054] The control unit 210 executes various programs stored in the storage unit. As an example, the control unit 210 executes a program for shortening the time from when the first substrate W1 and the second substrate W2 are opposed to each other until these substrates are bonded to each other.

[0055] The control unit 210 includes, as functional units realized by executing the program, a first imaging control unit 211, a second imaging control unit 212, and a bonding control unit 213. Note that, hereinafter, the processes described as being performed by the first imaging control unit 211, the second imaging control unit 212, and the bonding control unit 213 are processes realized by the control unit 210.

[0056] The first imaging control unit 211 uses the first imaging unit to image the first substrate W1 including the first alignment mark M1 and / or the second substrate W2 including the second alignment mark M2 on the temporary placement table 60 before the first substrate W1 is held by the first holding unit 105 and before the second substrate W2 is held by the second holding unit 110. It is preferable that the first imaging control unit 211 captures images of the first alignment mark M1 and the second alignment mark M2. However, the imaging by the first imaging control unit 211 is performed using the wide-area objective lens 71. Considering that, in subsequent processing, the first alignment mark M1 is captured using the first local objective lens 121a, both of which have higher magnification than the wide-area objective lens 71, and the second alignment mark M2 is captured using the second local objective lens 122a, the accuracy required for the imaging processing by the first imaging control unit 211 may be relatively lower than that required for the imaging processing by the second imaging control unit 212, which will be described later. Therefore, it is sufficient for the first imaging control unit 211 to capture an image of at least one of the first substrate W1 and the second substrate W2. Specific processing details will be described in the bonding method, which will be described later.

[0057] The second imaging control unit 212 causes the second imaging unit 120 to capture images of the first alignment mark M1 on the first substrate W1 held by the first holding unit 105 and the second alignment mark M2 on the second substrate W2 held by the second holding unit 110. Specific processing details will be explained in the bonding method described below.

[0058] The bonding control unit 213 aligns the first alignment mark M1 with the second alignment mark M2 based on the imaging result of the second imaging unit 120 by the second imaging control unit 212. Then, with this alignment performed, the first holding unit 105 and the second holding unit 110, which are arranged opposite each other, are brought relatively close to each other, thereby bonding the first substrate W1 and the second substrate W2. This produces a bonded substrate W3 in which the first substrate W1 and the second substrate W2 are bonded together. Specific processing details will be described later in the bonding method section.

[0059] (Joining method) Next, a method for bonding substrates according to an embodiment will be described. Fig. 6 is a flowchart showing an example of the bonding method. The bonding method includes a first imaging step S10, a first holding step S11, a second holding step S12, a first positioning step S13, a second imaging step S14, a second positioning step S15, a third imaging step S16, a fine alignment step S17, a retraction step S18, and a bonding step S19. The processing of each of these steps is executed by the control unit 210.

[0060] In the bonding method according to the embodiment, before performing the first imaging step S10, the control unit 210 performs a plasma activation process to bond the first substrate W1 and the second substrate W2 by supplying a plasma-like gas to the surface 11 of the first substrate W1 and the surface 21 of the second substrate W2, which will be the bonding surfaces, to activate the respective bonding surfaces. By performing this plasma activation process, surface impurities such as organic matter adsorbed on the surfaces of the first substrate W1 and the second substrate W2 are removed, exposing clean surfaces. Furthermore, hydroxyl groups (OH groups) bond to the exposed clean surfaces. That is, OH groups are formed on the surfaces of the first substrate W1 and the second substrate W2 activated by the plasma activation process. The first substrate W1 and the second substrate W2 that have undergone this plasma activation process are then housed in the cassette C1 in the first housing space 40a.

[0061] In the first imaging step S10, as shown in (a) of FIG. 7, the control unit 210 causes the transport unit 50 to transport, for example, the first substrate W1 from the cassette C1 to the temporary placement table 60. After the first substrate W1 has been transported to the temporary placement table 60, the control unit 210 uses the function of the first imaging control unit 211 to capture an image of the first substrate W1, including the first alignment mark M1, using the first imaging unit 70 (see (b) of FIG. 7). In the imaging in the first imaging step S10, the first substrate W1 is imaged to obtain the relative position of the first alignment mark M1 with respect to the center of the first substrate W1. As described above, the storage unit stores in advance a correction value for aligning the center of the temporary placement table 60 with the centers of the first holder 105 and the second holder 110. The correction value may include, for example, a deviation amount that takes into account the operation of the arm 52 constituting the transport unit 50. Therefore, the control unit 210 transports the first substrate W1 to the first holding unit 105 and determines the position of the first alignment mark M1, taking into account the correction value stored in the memory unit and the first alignment mark M1 relative to the center of the first substrate W1 obtained by imaging in the first imaging step S10.

[0062] Note that the center of the first substrate W1 may be obtained by directly capturing an image using the first imaging unit 70. Alternatively, for example, the control unit 210 may obtain the center by rotating the temporary placement table 60 and capturing images of at least three points on the edge portion (outer periphery) of the first substrate W1 using the first imaging unit 70. The control unit 210 may also detect a notch 15 formed in the first substrate, and determine the position of the first alignment mark M1 based on the position of the detected notch 15 and the obtained position of the center of the first substrate W1.

[0063] In the embodiment, only the first substrate W1 is imaged in the first imaging step S10. However, the second substrate W2 may be imaged instead of the first substrate W1, and similar processing may be performed. Alternatively, the second substrate W2 may be imaged in addition to the first substrate W1. That is, in the first imaging step S10, processing may be performed on at least one of the first substrate W1 and the second substrate W2. This is because, if alignment of the center position of at least one substrate W has been performed, the position of the other substrate may be adjusted based on the position of the one substrate whose center position has been aligned in the fine alignment step S17 described below. Note that if processing in the first imaging step S10 is performed on both the first substrate W1 and the second substrate W2, the amount of this position adjustment can be reduced. In the following description, it is assumed that imaging in the first imaging step S10 is performed on only the first substrate W1.

[0064] 8(a), the control unit 210 causes the first substrate W1 to be held by the first holding unit 105. That is, the control unit 210 causes the transport unit 50 to transport the first substrate W1 from the temporary placement table 60 to the first holding unit 105, with the surface to be bonded to the second substrate W2 facing downward, and causes the first holding unit 105 to hold the surface opposite to the bonding surface. At this time, the control unit 210 transports the first substrate W1 to the first holding unit 105 and causes the first holding unit 105 to hold it, taking into consideration the correction value for aligning the center of the temporary placement table 60 with the center of the first holding unit 105, and the difference between the center of the first substrate W1 and the center of the temporary placement table 60, which were described in the first imaging step S10 above.

[0065] 8(b), the control unit 210 causes the second holding unit 110 to hold the second substrate W2. That is, the control unit 210 causes the transport unit 50 to transport the second substrate W2 accommodated in the cassette C1 to the second holding unit 110, and causes the second substrate W2 to be held by the second holding unit 110 with the bonding surface with the first substrate W1 facing upward. Note that the order of the first holding step S11 and the second holding step S12 may be reversed.

[0066] In the first positioning step S13, the control unit 210 uses the moving unit 130 to move the first imaging unit 121 in the second imaging unit 120 to an imaging position corresponding to the position where the first alignment mark M1 on the first substrate W1 is formed, and adjusts the focus of the first local objective lens 121a to the first substrate W1 (see FIG. 9). In addition, the control unit 210 controls the lifting mechanism to lower the first holding unit 105 until it reaches a predetermined height position, thereby bringing the first holding unit 105 closer to the second holding unit 110.

[0067] 10, based on the imaging position moved in the first positioning step S13, the control unit 210 images the first alignment mark M1 using the first local objective lens 121a of the first imaging unit 121. The imaging result is output to the control unit 200.

[0068] Similarly, in the second positioning step S15, the control unit 210 moves the second imaging unit 122 in the second imaging unit 120 to an imaging position corresponding to the position where the second alignment mark M2 on the second substrate W2 is formed, and focuses the second local objective lens 122a on the second substrate W2. Note that in this second positioning step S15, the control unit 210 may adjust the distance between the first holding unit 105 and the second holding unit 110 by controlling the lifting mechanism.

[0069] 10, based on the imaging position moved in the second positioning step S15, the control unit 210 images the second alignment mark M2 using the second local objective lens 122a of the second imaging unit 122. The imaging result is output to the control unit 200.

[0070] Note that, because the first imaging unit 121 and the second imaging unit 122 are both attached to the moving unit 130 and can move together, the first positioning step S13 and the second imaging step S14 and the second positioning step S15 and the third imaging step S16 may be performed simultaneously. Performing these steps simultaneously can shorten the time required to bond the first substrate W1 and the second substrate W2. In addition, although the embodiment has been described as an example in which the image of the first substrate W1 is taken before the image of the second substrate W2 is taken, the order may be reversed. That is, the order of the first positioning step S13 and the second imaging step S14 and the second positioning step S15 and the third imaging step S16 may be reversed.

[0071] In the fine alignment step S17, the control unit 210 controls the adjustment unit 106 to adjust the horizontal position of the first holding unit 105 based on the image of the first substrate W1 captured by the first local objective lens 121a in the first imaging unit 121 and the image of the second substrate W2 captured by the second imaging unit 122 using the second local objective lens 122a. For example, the control unit 210 controls the adjustment unit 106 to adjust the horizontal position of the first holding unit 105, thereby matching the shapes of the first alignment mark M1 and the second alignment mark M2. Note that the "match" of shapes in this fine alignment step S17 does not necessarily mean a perfect match, but may include a predetermined amount of misalignment. The threshold value α for this predetermined amount of misalignment is a predetermined value that allows for misalignment between the substrates. This is because the process of this fine alignment step S17 is the final alignment process between the first alignment mark M1 and the second alignment mark M2. The control unit 210 repeatedly executes a series of processes including the first positioning step S13, the second imaging step S14, the second positioning step S15, and the third imaging step S16 until the amount of deviation becomes within the threshold value α.

[0072] In the retraction step S18, the control unit 210 moves the moving unit 130 to a predetermined retraction position that is located away from the image capturing position between the first holding unit 105 and the second holding unit 110, as shown in Fig. 11. In the example shown in Fig. 11, the moving unit 130 is retracted from the image capturing position by moving the moving unit 130 in the Y-axis direction.

[0073] In the bonding step S19, as shown in FIG. 12, the control unit 210 controls the lifting mechanism (not shown) to press the first holding unit 105 together with the shaft 107 in a direction to bring them closer to the second holding unit 110. As a result, the first substrate W1 and the second substrate W2 gradually approach each other and are bonded together. Note that before performing the bonding step S19, the control unit 210 performs a decompression process to decompress the internal space of the chamber 102. As a result, the inside of the chamber 102 is placed in a high vacuum state. In this high vacuum state, the bonding step S19 is performed. When the bonding step S19 is performed, a bonded substrate W3 is produced in which the first substrate W1 and the second substrate W2 are bonded together.

[0074] Through this series of processes, hydrogen atoms of OH groups formed on the surface of the first substrate W1 form hydrogen bonds with oxygen atoms of OH groups formed on the surface of the second substrate W2. Similarly, hydrogen atoms of OH groups formed on the surface of the second substrate W2 form hydrogen bonds with oxygen atoms of OH groups formed on the surface of the first substrate W1. These hydrogen bonds attract the first substrate W1 and the second substrate W2 to each other, temporarily bonding them together.

[0075] Thereafter, the control unit 210 releases the atmosphere in the chamber 102, releases the suction hold of the first substrate W1 by the first holding unit 105, and releases the suction hold of the second substrate W2 by the second holding unit 110, and transports the generated bonded substrate W3 to the cassette C2 by the transport unit 50 and stores it in the cassette C2.

[0076] The bonded substrate W3 thus temporarily bonded is then heated in an annealing apparatus (not shown), and water (H2O) is lost from the OH groups formed on the surfaces of the bonded first substrate W1 and second substrate W2, forming covalent bonds via oxygen bonds. This further improves the bond strength, transforming the temporary bond into a complete bond. The bonded substrates thus formed become a bonded substrate W3, as shown in FIG. 13, for example.

[0077] Thus, in this embodiment, before the second imaging unit 120 images the alignment marks M of the first substrate W1 held by the first holding unit 105 and the second substrate W2 held by the second holding unit 110, the substrate W is imaged by the first imaging unit 70, which has a lower magnification than the second imaging unit 120. This allows rough alignment to be completed before the substrates are placed facing each other in the chamber 102, so that alignment processing with the substrates placed facing each other requires only alignment using the high-magnification first local objective lens 121a and second local objective lens 122a. Therefore, for example, the time required to bond the substrates can be shortened compared to when alignment processing with a low-magnification objective lens and alignment processing with a high-magnification objective lens are performed with the substrates placed facing each other. Furthermore, shortening the time required to bond the substrates can improve productivity of the bonded substrate W3.

[0078] Although the embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0079] For example, in the above-described embodiment, the first local objective lens 121a of the first imaging unit 121 and the second local objective lens 122a of the second imaging unit 122 are arranged in parallel on the same plane so that their optical axes are not aligned on the same line. However, the arrangement may be such that their optical axes are aligned on the same line, as shown in Fig. 14, for example. That is, as shown in Fig. 14, the first local objective lens 121a that images the first substrate W1 arranged above is arranged above the second local objective lens 122a, and the second local objective lens 122a is arranged relatively lower. Note that in Fig. 14, (a) of Fig. 14 shows an example of the second imaging unit 120 when viewed from above, and (b) of Fig. 14 shows an example of the second imaging unit 120 when viewed from the side.

[0080] With this arrangement, the optical axis of the first local objective lens 121a and the optical axis of the second local objective lens 122a are aligned on the same straight line in the vertical direction. Since the optical axes are aligned on the same straight line, for example, when the first substrate W1 and the second substrate W2 are imaged, their coordinates in the horizontal direction will match, which makes it easier to align the first alignment mark M1 of the first substrate W1 with the second alignment mark M2 of the second substrate W2 in the fine alignment step S17.

[0081] In the above-described embodiment, the first substrate W1 and the second substrate W2 each have one alignment mark, but the first substrate W1 and the second substrate W2 may each have multiple alignment marks. For example, multiple alignment marks may be formed at the same position on the first substrate W1 and the second substrate W2. In such a case, when the first imaging unit 121 and the second imaging unit 122 are arranged side by side on the same plane as described above, the alignment accuracy can be improved even if different corresponding alignment marks M are captured.

[0082] Furthermore, in the above-described embodiment, in order to image the alignment mark M with the second imaging unit 120, the second imaging unit 120 is moved to a predetermined imaging position by moving the moving unit 130 to which the second imaging unit 120 is attached, but the second imaging unit 120 may also be positioned at a predetermined imaging position by relatively moving the first holding part 105 and the second holding part 110 that hold the substrate W.

[0083] The substrate bonding method described in the above-described embodiment can be realized by executing a prepared control program on a computer. The control program is recorded on a computer-readable storage medium and executed by being read from the storage medium. The control program may be provided in a form stored on a non-transitory storage medium such as a flash memory, or may be provided via a network such as the Internet. The computer that executes the control program may be included in a processing device, or may be included in an electronic device such as a smartphone, tablet, or personal computer that can communicate with the processing device, or may be included in a server device that can communicate with these processing devices and electronic devices.

[0084] This specification describes at least the following items. Note that the components in parentheses correspond to those in the above-described embodiment, but are not limited to these.

[0085] (1) A bonding apparatus (bonding apparatus 1) that bonds a first substrate (first substrate W1) and a second substrate (second substrate W2), a first holding part (first holding part 105) that holds the first substrate; a second holding portion (second holding portion 110) that is disposed opposite the first holding portion and holds the second substrate to be bonded to the first substrate; a first imaging unit (first imaging unit 70) capable of capturing images of a first alignment mark (first alignment mark M1) formed on the first substrate and a second alignment mark (second alignment mark M2) formed on the second substrate; a second imaging unit (second imaging unit 120) having a first imaging section (first imaging section 121) that images the first alignment mark formed on the first substrate and a second imaging section (second imaging section 122) that images the second alignment mark formed on the second substrate, and capable of imaging at a higher magnification than the first imaging unit; a moving unit (moving unit 130) that moves the second imaging unit, the first holding unit, and the second holding unit relatively in a region between the first holding unit and the second holding unit; a control unit (control unit 210) that controls the joining device, The control unit a first imaging control unit (first imaging control unit 211) that captures an image of the first alignment mark by the first imaging unit before the first holding unit holds the first substrate and / or the second alignment mark by the second holding unit; a second imaging control unit (second imaging control unit 212) that captures an image of the first alignment mark of the first substrate held by the first holding unit and the second alignment mark of the second substrate held by the second holding unit using the second imaging unit; Bonding equipment.

[0086] According to (1), since rough alignment can be completed using the first imaging unit before the substrates are placed face to face, the alignment process with the substrates placed face to face only requires high-precision alignment using the second imaging unit, which is capable of capturing images at a higher magnification than the first imaging unit. This reduces the time required to bond the substrates together compared to, for example, performing alignment processes using a low-magnification objective lens and a high-magnification objective lens with the substrates placed face to face. Furthermore, reducing the time required to bond the substrates together improves productivity of bonded substrates.

[0087] (2) The joining device according to (1) or (2), The first imaging unit includes a first objective lens (first local objective lens 121a), The second imaging unit includes a second objective lens (second local objective lens 122a), A bonding device in which the optical axis of the first objective lens and the optical axis of the second objective lens are not arranged on the same straight line.

[0088] According to (2), since the optical axis of the first objective lens and the optical axis of the second objective lens are not arranged on the same straight line, the distance between the first substrate and the second substrate held by each holding portion can be made shorter than when, for example, the optical axis of the first objective lens and the optical axis of the second objective lens are arranged on the same straight line, and as a result, it is possible to suppress the occurrence of positional misalignment between the substrates when the bonded substrate is produced.

[0089] (3) The joining device according to (1), The first imaging unit includes a first objective lens (first local objective lens 121a), The second imaging unit includes a second objective lens (second local objective lens 122a), The optical axis of the first objective lens and the optical axis of the second objective lens are arranged on the same straight line. Bonding equipment.

[0090] According to (3), by arranging the optical axis of the first objective lens and the optical axis of the second objective lens on the same straight line, when, for example, the first substrate and the second substrate are imaged, their respective horizontal coordinates will match, making it easier to align the first alignment mark of the first substrate with the second alignment mark of the second substrate than when their optical axes are not arranged on the same straight line.

[0091] (4) A bonding method for bonding a first substrate (first substrate W1) and a second substrate (second substrate W2), comprising: a first imaging step (first imaging step S10) of imaging a first alignment mark (first alignment mark M1) formed on the first substrate and / or a second alignment mark (second alignment mark M2) formed on the second substrate bonded to the first substrate with a first imaging unit (first imaging unit 70); a first holding step (first holding step S11) of holding the first substrate by a first holding unit (first holding unit 105) after the first imaging step; a second holding step (second holding step S12) in which the second substrate is held by a second holding unit (second holding unit 110) arranged opposite to the first holding unit after the first imaging step; a first positioning step (first positioning step S13) of positioning a second imaging unit (second imaging unit 120) having a first imaging section (first imaging section 121) that images the first alignment mark of the first substrate held by the first holding section and a second imaging section (second imaging section 122) that images the second alignment mark of the second substrate held by the second holding section in a region between the first holding section and the second holding section in order to image the first alignment mark with the first imaging section; a second imaging step (second imaging step S14) of imaging the first alignment mark using the first imaging unit after the first positioning step; a second positioning step (second positioning step S15) of positioning the second imaging unit in the region between the first holding part and the second holding part so that the second imaging part captures an image of the second alignment mark; a third imaging step (third imaging step S16) of imaging the second alignment mark using the second imaging unit after the second positioning step; a retracting step (retracting step S18) of retracting the second imaging unit positioned in the region between the first holding part and the second holding part; a bonding step (bonding step S19) of bonding the first substrate held by the first holding unit and the second substrate held by the second holding unit after the retreating step, The first imaging step performs imaging at a lower magnification than the second imaging step and the third imaging step. Joining method.

[0092] According to (4), the time required to bond the substrates can be reduced compared to, for example, performing an alignment process using a low-magnification objective lens and an alignment process using a high-magnification objective lens while the substrates are facing each other. In addition, by reducing the time required to bond the substrates in this way, the productivity of bonded substrates can be improved.

[0093] (5) The joining method according to (4), The first positioning step and the second imaging step, and the second positioning step and the third imaging step are performed simultaneously. Joining method.

[0094] According to (5), the first alignment mark and the second alignment mark can be imaged simultaneously, which results in a shorter time required to bond the substrates together. [Explanation of symbols]

[0095] 1 Bonding equipment 70 First Imaging Unit 105 1st holding part 110 32nd holding part 120 Second imaging unit 121 First imaging unit 121a First local objective lens (first objective lens) 122 Second imaging unit 122a Second local objective lens (second objective lens) 130 Mobile Unit 210 Control Unit 211 First imaging control unit 212 Second imaging control unit M1 First alignment mark M2 Second alignment mark W1 First board W2 Second board S10 First imaging step S11 First holding step S12 Second holding step S14 Second imaging step S16 Third imaging step S18 Evacuation step S19 Bonding step

Claims

1. A bonding device for bonding a first substrate and a second substrate, a first holding portion that holds the first substrate; a second holding portion disposed opposite the first holding portion and configured to hold the second substrate to be bonded to the first substrate; a first imaging unit capable of capturing images of a first alignment mark formed on the first substrate and a second alignment mark formed on the second substrate; a second imaging unit having a first imaging section that images the first alignment mark formed on the first substrate and a second imaging section that images the second alignment mark formed on the second substrate, the second imaging unit being capable of imaging at a higher magnification than the first imaging unit; a moving unit that moves the second imaging unit, the first holding unit, and the second holding unit relatively in a region between the first holding unit and the second holding unit; a control unit that controls the joining device, The control unit a first imaging control unit that uses the first imaging unit to capture an image of the first alignment mark before the first holding unit holds the first substrate and / or the second alignment mark before the second holding unit holds the second substrate; a second imaging control unit that uses the second imaging unit to capture images of the first alignment mark of the first substrate held by the first holding unit and the second alignment mark of the second substrate held by the second holding unit, Bonding equipment.

2. The joining device according to claim 1, the first imaging unit includes a first objective lens; the second imaging unit includes a second objective lens; A cementing device in which the optical axis of the first objective lens and the optical axis of the second objective lens are not arranged on the same straight line.

3. The joining device according to claim 1, the first imaging unit includes a first objective lens; the second imaging unit includes a second objective lens; The optical axis of the first objective lens and the optical axis of the second objective lens are arranged on the same straight line. Bonding equipment.

4. A bonding method for bonding a first substrate and a second substrate, comprising: a first imaging step of imaging, with a first imaging unit, a first alignment mark formed on the first substrate and / or a second alignment mark formed on the second substrate bonded to the first substrate; a first holding step of holding the first substrate by a first holding unit after the first imaging step; a second holding step of holding the second substrate by a second holding part disposed opposite to the first holding part after the first imaging step; a first positioning step of positioning a second imaging unit having a first imaging section that images the first alignment mark of the first substrate held by the first holding section and a second imaging section that images the second alignment mark of the second substrate held by the second holding section in a region between the first holding section and the second holding section so that the first imaging section images the first alignment mark; a second imaging step of imaging the first alignment mark using the first imaging unit after the first positioning step; a second positioning step of positioning the second imaging unit in the region between the first holding part and the second holding part so that the second imaging unit captures an image of the second alignment mark; a third imaging step of imaging the second alignment mark using the second imaging unit after the second positioning step; a retracting step of retracting the second imaging unit positioned in the region between the first holding portion and the second holding portion; a bonding step of bonding the first substrate held by the first holding unit and the second substrate held by the second holding unit after the retracting step, The first imaging step performs imaging at a lower magnification than the second imaging step and the third imaging step. Joining method.

5. The joining method according to claim 4, the first positioning step and the second imaging step, and the second positioning step and the third imaging step are performed simultaneously; Joining method.

Images