Bonding apparatus and bonding method

Abstract

To suppress displacement between substrates when the substrates are joined to each other.SOLUTION: An imaging unit 120 including a first holder 105 configured to hold a first substrate W1, a second holder 110 configured to hold a second substrate W1 arranged to face the first holder 105 and joined to the first substrate W2, a first imaging unit 121 including a first wide-area objective lens W1 for imaging a first alignment mark M1 of the first substrate 121a, and a second imaging unit 122 including a second wide-area objective lens W2 for imaging a second alignment mark M2 of the second substrate 122a; And a moving unit 130 for relatively moving the imaging unit 120, the first holding part 105 and the second holding part 110 in an area between the first holding part 105 and the second holding part 110, and in the imaging unit 120, the optical axis of the first wide-area objective lens 121a and the optical axis of the second wide-area objective lens 122a are not arranged on the same line.SELECTED DRAWING: Figure 5

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 substrates via such an oxide film, once the substrates are bonded together, it is difficult to redo the process thereafter, so it is desirable to suppress misalignment between the substrates when bonding them together.

[0005] The present invention provides a bonding apparatus and a bonding method that can suppress misalignment between substrates when bonding the 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; an imaging unit including a first imaging section including a first objective lens that images a first alignment mark formed on the first substrate held by the first holding section, and a second imaging section including a second objective lens that images a second alignment mark formed on the second substrate held by the second holding section; a moving unit that moves the 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, The imaging unit 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.

[0007] Another aspect of the present invention is A bonding method for bonding a first substrate and a second substrate, comprising: a first holding step of holding the first substrate with a first holding part; a second holding step of holding the second substrate with a second holding part disposed opposite the first holding part; a first positioning step of positioning an imaging unit having a first imaging section including a first objective lens that images a first alignment mark formed on the first substrate held by the first holding section, and a second imaging section that images a second alignment mark formed on the second substrate held by the second holding section and includes a second objective lens having an optical axis that is not aligned with the optical axis of the first objective lens, in a region between the first holding section and the second holding section in order to image the first alignment mark with the first objective lens; a first imaging step of imaging the first alignment mark using the imaging unit after the first positioning step; a second positioning step of positioning the imaging unit within the region between the first holding part and the second holding part to image the second alignment mark with the second objective lens; a second imaging step of imaging the second alignment mark using the imaging unit after the second positioning step; a retracting step of retracting the imaging unit positioned in the region between the first holding part and the second holding part; After the retreating step, a bonding step of bonding the first substrate and the second substrate is provided. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress misalignment between substrates when bonding the substrates together. [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 holding step S10 and the second holding step S11. [Figure 8] FIG. 8 is a diagram for explaining the first positioning step S12 and the second positioning step S14. [Figure 9] FIG. 9 is a diagram for explaining each imaging step. [Figure 10] FIG. 10 is a diagram for explaining the retraction step S20. [Figure 11] FIG. 11 is a diagram for explaining the joining step S21. [Figure 12] FIG. 12 is a perspective view showing an example of the bonded substrate W3. [Figure 13]FIG. 13 is a diagram for explaining a comparative example of the first imaging unit and the second imaging unit. 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. 12) 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] The first substrate W1 and the second substrate W2 are bonded together by a bonding apparatus 1, but once the substrates are bonded together, it is difficult to redo the process, so it is preferable to prevent misalignment between the opposing substrates when bonding them together. Therefore, in the embodiment, a bonding apparatus 1 is configured that can prevent such misalignment between the substrates.

[0022] (Joining equipment) Fig. 3 schematically shows 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 perpendicular to the X-axis direction on a horizontal plane, and the Z-axis direction is a direction perpendicular to the X-axis and Y-axis directions.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] The transport unit 50 transports the substrate W between the cassette housing 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 unloads the first substrate W1 and the second substrate W2 before bonding from the cassette C1 and loads them onto the temporary placement table 60, and unloads the first substrate W1 and the second substrate W2 from the temporary placement table 60 and loads them into the bonding unit 100. Alternatively, the transport unit 50 unloads the first substrate W1 and the second substrate W2 before bonding from the cassette C1 and loads them into the bonding unit 100. The transport unit 50 also unloads 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 housing space 40b.

[0027] 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 an imaging mechanism 70 that images the transported substrate W. The imaging mechanism 70 can perform a process equivalent to a pre-alignment step S16 (described later) based on the image of the substrate W and the alignment marks M formed on the substrate W. Note that the process equivalent to the pre-alignment step S16 does not necessarily have to be performed on the temporary placement table 60, and may be performed on the temporary placement table 60 or in the bonding unit 100 (described later). In the embodiment, an example in which the pre-alignment step S16 is performed in the bonding unit 100 will be described, and therefore a detailed description of the process that can be performed on the temporary placement table 60 will be omitted.

[0028] 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.

[0029] 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, an 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 imaging unit 120.

[0030] The first holding unit 105 is a holding unit that holds the first substrate W1 by suction, 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 joining surface with the second substrate W2 (i.e., front surface 11) facing downward. The lower surface of the first holding unit 105 is a holding surface made of, for example, porous ceramic, and holds the first substrate W1 by suction by operating a suction source (not shown).

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The 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 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.

[0036] As shown in (a) of Figure 5, the first imaging unit 121 has a first wide-area objective lens 121a, which is a wide-area macro lens, and a first local objective lens 121b, which is a micro lens that has a higher magnification than the first wide-area objective lens 121a and is capable of relatively high-resolution imaging, as lenses for imaging the first alignment mark M1 formed on the first substrate W1.

[0037] The first imaging unit 121 uses the first wide-area objective lens 121a to capture an image of the first substrate W1, including the first alignment mark M1, over a relatively wide range. Furthermore, the first imaging unit 121 uses the first local objective lens 121b to capture an image of the first alignment mark M1 on the first substrate W1 with higher resolution than when the first wide-area objective lens 121a is used. Note that the first imaging unit 121 can adjust the focal points of the first wide-area objective lens 121a and the first local objective lens 121b to the first substrate W1.

[0038] Similarly, as shown in (a) of Figure 5, the second imaging unit 122 has a second wide-area objective lens 122a, which is a wide-area macro lens, and a second local objective lens 122b, which is a micro lens with a higher magnification than the second wide-area objective lens 122a and is capable of relatively high-resolution imaging, as lenses for imaging the second alignment mark M2 formed on the second substrate W2.

[0039] The second imaging unit 122 uses the second wide-area objective lens 122a to capture an image of the second substrate W2, including the second alignment mark M2, over a relatively wide range. Furthermore, the second imaging unit 122 uses the second local objective lens 122b to capture an image of the second alignment mark M2 on the second substrate W2 with higher resolution than when the second wide-area objective lens 122a is used. The second imaging unit 122 can adjust the focal points of the second wide-area objective lens 122a and the second local objective lens 122b to the second substrate W2.

[0040] The first imaging unit 121 is attached to a moving unit 130 (described later) with the first wide-area objective lens 121a and the first local-area objective lens 121b facing upward. The second imaging unit 122 is attached to a moving unit 130 (described later) with the second wide-area objective lens 122a and the second local-area objective lens 122b facing downward.

[0041] In this embodiment, the arrangement of the first wide-area objective lens 121a, the first local-area objective lens 121b, the second wide-area objective lens 122a, and the second local-area objective lens 122b (hereinafter also collectively referred to as "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 viewed from above, and Fig. 5(b) shows the arrangement of the lenses when viewed from the side.

[0042] 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 shown in Fig. 5, each lens is arranged in parallel in a planar region in the X-axis direction and in a planar region in the Y-axis direction orthogonal to the X-axis direction.

[0043] More specifically, by arranging the first wide-area objective lens 121a and the second wide-area objective lens 122a in parallel, the optical axis of the first wide-area objective lens 121a and the optical axis of the second wide-area objective lens 122a are not arranged on the same line. Similarly, by arranging the first local-area objective lens 121b and the second local-area objective lens 122b in parallel, the optical axis of the first local-area objective lens 121b and the optical axis of the second local-area objective lens 122b are not arranged on the same line. Furthermore, the optical axes of the four lenses are not arranged on the same line.

[0044] 5(a), the first wide-area objective lens 121a, the second wide-area objective lens 122a, the first local-area objective lens 121b, and the second local-area objective lens 122b are arranged in a "T" shape in plan view. In other words, the lenses are arranged in a "2 x 2" grid.

[0045] Furthermore, when this arrangement is defined in relation to the movement direction of moving unit 130, which will be described later, it can also be defined as follows. For example, first wide-area objective lens 121a, second wide-area objective lens 122a, first local-area objective lens 121b, and second local-area objective lens 122b are arranged overlapping one another so that the two objective lenses are visible when viewed from one movement direction of the moving unit (for example, the Y-axis direction), and also so that the two objective lenses are visible when viewed from a direction perpendicular to that movement direction on the same plane (for example, the X-axis direction). In other words, it can be said that the lenses are arranged in a horizontal plane between the X-axis and Y-axis directions, divided into four equal-spaced sections.

[0046] In the example shown in (a) of Figure 5, the lenses are arranged clockwise from the top left in the order of the first wide-area objective lens 121a, the first local-area objective lens 121b, the second wide-area objective lens 122a, and the second local-area objective lens 122b, but the arrangement may be changed as appropriate.

[0047] In this way, the first wide-area objective lens 121a, the second wide-area objective lens 122a, the first local-area objective lens 121b, and the second local-area objective lens 122b 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. As a result, the distance between the opposing first holder 105 and second holder 110 can be shortened compared to when the optical axis of the upward-facing objective lens 300 that images the first substrate W1 and the optical axis of the downward-facing objective lens 400 that images the second substrate W2 are arranged collinear in the vertical direction, as shown in the comparative example of FIG. 13 . 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. 13(a) is an example of the objective lens 300 and the objective lens 400 when viewed from above, and FIG. 13(b) is an example of the objective lens 300 and the objective lens 400 when viewed from the side.

[0048] Returning to Fig. 4, the moving unit 130 will be described. The moving unit 130 moves the imaging unit 120 in the planar area between the first holding part 105 and the second holding part 110, that is, 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.

[0049] 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 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.

[0050] In this way, since the moving unit 130 is capable of moving 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 W as in the embodiment, or on the inner periphery of the substrate W, 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.

[0051] 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.

[0052] 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).

[0053] 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.

[0054] The control unit 210 executes various programs stored in the storage unit. As an example, the control unit 210 executes a program for suppressing misalignment when bonding substrates together. Specific processing content will be described in the bonding method below.

[0055] (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, as processing steps, a first holding step S10, a second holding step S11, a first positioning step S12, a first imaging step S13, a second positioning step S14, a second imaging step S15, a pre-alignment step S16, a third imaging step S17, a fourth imaging step S18, a fine alignment step S19, a retraction step S20, and a bonding step S21. The processing of each of these steps is executed by the control unit 210.

[0056] In the bonding method according to the embodiment, before performing the first holding 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.

[0057] 7(a), the control unit 210 causes the first holding unit 105 to hold the first substrate W1. That is, the control unit 210 causes the transport unit 50 to transport the first substrate W1 accommodated in the cassette C1 to the first holding unit 105, and causes the first holding unit 105 to hold the surface opposite to the surface to be joined with the second substrate W2 facing downward.

[0058] Similarly, in the second holding step S11, the control unit 210 causes the second holding part 110 to hold the second substrate W2, as shown in Fig. 7(b). That is, the control unit 210 transports the second substrate W2 accommodated in the cassette C1 to the second holding part 110 by the transport unit 50, and causes the second substrate W2 to be bonded to the first substrate W1 to face upward, and the surface opposite to the bonded surface to be held by the second holding part 110. Note that the order of the first holding step S10 and the second holding step S11 may be reversed.

[0059] In the first positioning step S12, the control unit 210 uses the moving unit 130 to move the first imaging unit 121 in the imaging unit 120 to an imaging position corresponding to the position where the first alignment mark M1 on the first substrate W1 is formed, for example, and adjusts the focus of the first wide-angle objective lens 121a on the first substrate W1 (see FIG. 8). The control unit 210 also controls the lifting mechanism (not shown) to lower the first holding unit 105 to a predetermined height position, thereby bringing the first holding unit 105 closer to the second holding unit 110. After positioning the first imaging unit 121 at the predetermined position in this way, the first substrate W1 is imaged using the first wide-angle objective lens 121a in the first imaging unit 121.

[0060] In the first imaging step S13, the control unit 210 images the first substrate W1 including the first alignment mark M1 using the first wide angle objective lens 121a based on the imaging position moved in the first positioning step S12, as shown in Fig. 9. The imaging result is output to the control unit 200.

[0061] Similarly, in the second positioning step S14, the control unit 210 moves the second imaging unit 122 in the 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 wide-area objective lens 122a on the second substrate W2. Note that in this second positioning step S14, 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. After positioning the second imaging unit 122 at the predetermined position in this way, the second substrate W2 is imaged using the second wide-area objective lens 122a in the second imaging unit 122.

[0062] In the second imaging step S15, the control unit 210 images the second substrate W2 including the second alignment mark M2 using the second wide-angle objective lens 122a based on the imaging position moved in the second positioning step S14. The imaging result is output to the control unit 200.

[0063] 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 S12 and the first imaging step S13 and the second positioning step S14 and the second imaging step S15 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 first and then the image of the second substrate W2 is taken, the order may be reversed. That is, the order of the first positioning step S12 and the first imaging step S13 and the second positioning step S14 and the second imaging step S15 may be reversed.

[0064] In the pre-alignment step S16, 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 imaging unit 121 using the first wide-angle objective lens 121a and the image of the second substrate W2 captured by the second imaging unit 122 using the second wide-angle 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 to match the shape of the first alignment mark M1 with the shape of the second alignment mark M2. Note that the "match" of the shapes in this pre-alignment step S16 does not necessarily mean a perfect match, but may refer to a predetermined amount of misalignment. The first positioning step S12 through the second imaging step S15 may then be repeatedly executed until the predetermined amount of misalignment is within the threshold value α.

[0065] In the third imaging step S17, the control unit 210 uses the moving unit 130 to move the imaging unit 120 to the position where the imaging was performed using the first wide-area objective lens 121a, and then focuses the first local objective lens 121b on the first substrate W1 to image the first alignment mark M1. The imaging result is output to the control unit 200.

[0066] Similarly, in the fourth imaging step S18, the control unit 210 uses the moving unit 130 to move the imaging unit 120 to the position where the imaging was performed using the second wide-area objective lens 122a, and then focuses the second local objective lens 122b on the second substrate W2 to image the second alignment mark M2. The imaging result is output to the control unit 200.

[0067] Note that, since the first imaging unit 121 and the second imaging unit 122 are both attached to the moving unit 130 and can move together, the fourth imaging step S18 may be performed simultaneously with the third imaging step S17. By performing these steps simultaneously, the time required to bond the first substrate W1 and the second substrate W2 can be shortened. Also, the order of the third imaging step S17 and the fourth imaging step S18 may be reversed.

[0068] In the fine alignment step S19, the control unit 210 controls the adjustment unit 106 to adjust the horizontal position of the first holding unit 105 based on the image capture result of the first substrate W1 captured by the first local objective lens 121b in the first imaging unit 121 and the image capture result of the second substrate W2 captured by the second imaging unit 122 using the second local objective lens 122b. For example, the control unit 210 controls the adjustment unit 106 to adjust the horizontal position of the first holding unit 105 to match 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 S19 does not necessarily mean perfect match, and may involve a predetermined amount of misalignment, with the threshold β for this predetermined amount of misalignment being a smaller value than the threshold α for the misalignment amount in the pre-alignment step S16. Furthermore, this threshold β is a predetermined value that allows for tolerance of misalignment between the substrates. This is because the process of this fine alignment step S19 is the process of final alignment between the first alignment mark M1 and the second alignment mark M2. The control unit 210 repeatedly executes the third imaging step S17 and the fourth imaging step S18 until the amount of deviation becomes within the threshold value β.

[0069] In the retraction step S20, the control unit 210 moves the moving unit 130 to a predetermined retraction position that is located away from the imaging position between the first holding unit 105 and the second holding unit 110, as shown in Fig. 10. In the example shown in Fig. 10, the moving unit 130 is retracted from the imaging position by moving the moving unit 130 in the Y-axis direction.

[0070] In the bonding step S21, as shown in FIG. 11, the control unit 210 controls the lifting mechanism to press the first holding unit 105 together with the shaft 107 toward 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. Before performing the bonding step S21, 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. The bonding step S21 is performed in this high vacuum state. When the bonding step S21 is performed, a bonded substrate W3 is produced in which the first substrate W1 and the second substrate W2 are bonded together.

[0071] 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.

[0072] 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.

[0073] The bonded substrate W3 thus temporarily bonded is then heated in an annealing device (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 bonding strength between the substrates, transforming them from a temporary bond to a fully bonded one. The bonded substrates thus formed become a bonded substrate W3, as shown in FIG. 12, for example.

[0074] 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.

[0075] For example, 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.

[0076] Furthermore, in the above-described embodiment, in order to image the alignment mark M with the imaging unit 120, the imaging unit 120 is moved to a predetermined imaging position by moving the moving unit 130 to which the imaging unit 120 is attached, but the 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.

[0077] 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.

[0078] 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.

[0079] (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; an imaging unit (imaging unit 120) having: a first imaging section (first imaging section 121) including a first objective lens (first wide-area objective lens 121a) that images a first alignment mark (first alignment mark M1) formed on the first substrate held by the first holding section; and a second imaging section (second imaging section 122) including a second objective lens (second wide-area objective lens 122a) that images a second alignment mark (second alignment mark M2) formed on the second substrate held by the second holding section; a moving unit (moving unit 130) that moves the 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, The imaging unit 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. Bonding equipment.

[0080] According to (1), because the optical axis of the first objective lens and the optical axis of the second objective lens are not aligned on the same line, the distance between the first holder that holds the first substrate and the second holder that holds the second substrate positioned opposite the first holder is shorter than, for example, a configuration in which the optical axes of the first objective lens and the second objective lens are aligned on the same line. Therefore, the distance between the first substrate and the second substrate held by each holder is also shorter, thereby preventing misalignment between the substrates when the bonded substrate is produced. Furthermore, because the distance between the first substrate and the second substrate can be shortened in this way, the time required to bring the substrates closer to each other can be shortened, which ultimately improves the productivity of bonded substrates.

[0081] (2) The joining device according to (1), the first imaging unit further includes a third objective lens (first local objective lens 121b) having a magnification higher than that of the first objective lens, the second imaging unit further includes a fourth objective lens (second local objective lens 122b) having a magnification higher than that of the second objective lens, The optical axis of the third objective lens and the optical axis of the fourth objective lens are not arranged on the same straight line. Bonding equipment.

[0082] According to (2), since the optical axis of the third objective lens, which has a magnification relatively lower than that of the first objective lens, and the optical axis of the fourth objective lens, which has a magnification relatively lower than that 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 shortened compared to a configuration in which, for example, the optical axis of the third objective lens and the optical axis of the fourth 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.

[0083] (3) The joining device according to (2), the optical axes of the first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are not arranged on the same straight line; Bonding equipment.

[0084] According to (3), since the optical axes of the first objective lens, the second objective lens, the third objective lens, and the fourth 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, any of the objective lenses is arranged on the same straight line as the other objective lenses, and as a result, it is possible to suppress the occurrence of misalignment between the substrates when the bonded substrate is produced.

[0085] (4) The joining device according to (3), the first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are arranged in a square shape in a plan view; Bonding equipment.

[0086] According to (4), the first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are arranged in a "T" shape in a planar view, so that the optical axes of each objective lens do not overlap on the same straight line. Therefore, the distance between the first substrate and the second substrate held by each holding portion can be made shorter than when, for example, any of the objective lenses is arranged on the same straight line as the other objective lenses. As a result, it is possible to suppress misalignment between the substrates when the bonded substrate is produced.

[0087] (5) The joining device according to (3), The first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are The two objective lenses are arranged overlapping each other so that they are visible when viewed from the movement direction (Y-axis direction, X-axis direction) of the moving unit, and are also arranged overlapping each other so that they are visible when viewed from directions perpendicular to the movement direction (X-axis direction, Y-axis direction) on the same plane.

[0088] According to (5), with this arrangement, the first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are arranged in four equally spaced sections in a horizontal plane between the X-axis and Y-axis directions. This means that the optical axes of the objective lenses do not overlap on the same line, and therefore the distance between the first substrate and the second substrate held by each holder can be made shorter than when, for example, any of the objective lenses is arranged on the same line as the other objective lenses. As a result, it is possible to prevent misalignment between the substrates when the bonded substrate is produced.

[0089] (6) A bonding method for bonding a first substrate (first substrate W1) and a second substrate (second substrate W2), comprising: a first holding step (first holding step S10) of holding the first substrate with a first holding unit (first holding unit 105); a second holding step (second holding step S11) of holding the second substrate with a second holding part (second holding part 110) arranged opposite to the first holding part; a first positioning step (first positioning step S12) of positioning an imaging unit (imaging unit 120) having a first imaging section (first imaging section 121) including a first objective lens (first wide-area objective lens 121a) that images a first alignment mark (first alignment mark M1) formed on the first substrate held by the first holding section, and a second imaging section (second imaging section 122) that images a second alignment mark (second alignment mark M2) formed on the second substrate held by the second holding section and includes a second objective lens (second wide-area objective lens 122a) having an optical axis that is not arranged on the same straight line as the optical axis of the first objective lens, the imaging unit being positioned in a region between the first holding section and the second holding section in order to image the first alignment mark with the first objective lens; a first imaging step (first imaging step S13) of imaging the first alignment mark using the imaging unit after the first positioning step; a second positioning step (second positioning step S14) of positioning the imaging unit within the region between the first holding part and the second holding part to image the second alignment mark with the second objective lens; a second imaging step (second imaging step S15) of imaging the second alignment mark using the imaging unit after the second positioning step; a retracting step (retracting step S20) of retracting the imaging unit positioned in the region between the first holding part and the second holding part; and a bonding step (bonding step S21) of bonding the first substrate and the second substrate after the retreating step. Joining method.

[0090] According to (6), the distance between the first substrate and the second substrate held by each holding unit is shortened, which prevents misalignment between the substrates when the bonded substrate is produced. Furthermore, shortening the distance between the first substrate and the second substrate in this way shortens the time it takes to bring the substrates close to each other, which in turn improves the productivity of the bonded substrate.

[0091] (7) The joining method according to (6), The first positioning step and the first imaging step, and the second positioning step and the second imaging step are performed simultaneously. Joining method.

[0092] According to (7), for example, the time required to produce the bonded substrate can be shortened compared to when the first positioning step and the first imaging step and the second positioning step and the second imaging step are not performed simultaneously, and as a result, the productivity of the bonded substrate can be improved. [Explanation of symbols]

[0093] 1 Bonding equipment 105 1st holding part 110 Second holding part 120 Imaging unit 121 First imaging unit 121a First wide-area objective lens (first objective lens) 121b First local objective lens (third objective lens) 122 Second imaging unit 122a Second wide-area objective lens (second objective lens) 122b Second local objective lens (fourth objective lens) 130 Mobile Unit M1 First alignment mark M2 Second alignment mark W1 First board W2 Second board S10 First holding step S11 Second holding step S12 First positioning step S13 First imaging step S14 Second positioning step S15 Second imaging step S20 Evacuation step S21 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; an imaging unit including a first imaging section including a first objective lens that images a first alignment mark formed on the first substrate held by the first holding section, and a second imaging section including a second objective lens that images a second alignment mark formed on the second substrate held by the second holding section; a moving unit that moves the 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, The imaging unit 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. Bonding equipment.

2. The joining device according to claim 1, the first imaging unit further includes a third objective lens having a magnification higher than that of the first objective lens, the second imaging unit further includes a fourth objective lens having a magnification higher than that of the second objective lens, The optical axis of the third objective lens and the optical axis of the fourth objective lens are not arranged on the same straight line. Bonding equipment.

3. The joining device according to claim 2, the optical axes of the first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are not arranged on the same straight line; Bonding equipment.

4. The joining device according to claim 3, the first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are arranged in a square shape in a plan view; Bonding equipment.

5. The joining device according to claim 3, The first objective lens, the second objective lens, the third objective lens, and the fourth objective lens are the two objective lenses are arranged so as to be overlapped with each other when viewed from the direction of movement of the moving unit, and are also arranged so as to be overlapped with each other when viewed from a direction perpendicular to the direction of movement on the same plane; Bonding equipment.

6. A bonding method for bonding a first substrate and a second substrate, comprising: a first holding step of holding the first substrate with a first holding part; a second holding step of holding the second substrate with a second holding part disposed opposite the first holding part; a first positioning step of positioning an imaging unit having a first imaging section including a first objective lens that images a first alignment mark formed on the first substrate held by the first holding section, and a second imaging section that images a second alignment mark formed on the second substrate held by the second holding section and includes a second objective lens having an optical axis that is not aligned with the optical axis of the first objective lens, in a region between the first holding section and the second holding section in order to image the first alignment mark with the first objective lens; a first imaging step of imaging the first alignment mark using the imaging unit after the first positioning step; a second positioning step of positioning the imaging unit in the region between the first holding part and the second holding part to image the second alignment mark with the second objective lens; a second imaging step of imaging the second alignment mark using the imaging unit after the second positioning step; a retracting step of retracting the imaging unit positioned in the region between the first holding portion and the second holding portion; a bonding step of bonding the first substrate and the second substrate after the retracting step, Joining method.

7. The joining method according to claim 6, the first positioning step and the first imaging step, and the second positioning step and the second imaging step are performed simultaneously; Joining method.

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