Method and apparatus for joining substrates

Abstract

The present invention provides a bonding method and bonding apparatus that can improve the accuracy of the alignment of substrates. [Solution] A method for joining a first substrate W1 and a second substrate W2, comprising a first holding step S1, a second holding step S2, a detection step S3, a positioning step S4, and a joining step S5. The detection step S3 detects alignment marks M1 and M2 formed on the outer periphery portions 16 and 26 of the first substrate W1 and the second substrate W2 from a position that does not overlap the first substrate W1 and the second substrate W2 when viewed from the opposing direction in which the first substrate W1 and the second substrate W2 face each other. The positioning step S4 positions the first substrate W1 and the second substrate W2 relative to each other based on the alignment marks M1 and M2 detected in the detection step S3.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for bonding substrates that bond a first substrate and a second substrate.

Background Art

[0002] Conventionally, a technique for bonding a plurality of substrates to each other is known. For example, Patent Document 1 discloses a technique for bonding a silicon substrate having a plurality of devices formed on its surface and a support member made of a silicon substrate to each other at room temperature through an oxide film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the bonding of substrates as described in Patent Document 1, once the substrates are bonded, it is difficult to rework them, so it is desired to improve the accuracy of alignment between the substrates before bonding.

[0005] The present invention provides a method and an apparatus for bonding substrates that can improve the accuracy of alignment between the substrates.

Means for Solving the Problems

[0006] The present invention is a method for bonding substrates that bond a first substrate and a second substrate, comprising a first holding step of holding the first substrate by a first holding portion, a second holding step of holding the second substrate by a second holding portion arranged to face the first holding portion, A detection step of detecting alignment marks formed on the outer periphery of the first substrate and the second substrate from a position that does not overlap the first substrate and the second substrate when viewed from the opposing direction in which the first substrate and the second substrate face each other, A positioning step in which the first substrate and the second substrate are positioned relative to each other based on the alignment marks detected in the detection step, The system includes a bonding step of bonding the first substrate and the second substrate that were positioned in the positioning step.

[0007] Furthermore, the present invention is A substrate bonding apparatus for bonding a first substrate and a second substrate, A first holding portion that holds the first substrate, A second holding portion is positioned opposite the first holding portion and holds the second substrate, A detection unit that detects alignment marks formed on the outer periphery of the first substrate and the second substrate from a position that does not overlap the first substrate and the second substrate when viewed from the opposing direction in which the first substrate and the second substrate face each other, The system includes a positioning unit that positions the first substrate and the second substrate relative to each other based on the alignment marks detected by the detection unit. [Effects of the Invention]

[0008] According to the present invention, the accuracy of the alignment of substrates can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] (a) is a perspective view showing an example of the first substrate W1, and (b) is a perspective view showing an example of the second substrate W2. [Figure 2] (a) is a diagram illustrating the bonding of the first substrate W1 and the second substrate W2, and (b) is a perspective view showing an example of a bonded substrate W3. [Figure 3] This is a perspective view showing bonding apparatus 1 of one embodiment of the present invention. [Figure 4]It is a diagram for explaining an example of the joining unit 100. [Figure 5] It is a flowchart showing a joining method according to an embodiment of the present invention. [Figure 6] It is a diagram for explaining the first holding step S1. [Figure 7] It is a diagram for explaining the second holding step S2. [Figure 8] It is a diagram for explaining the detection step S3 and the positioning step S4. [Figure 9] It is a diagram for explaining the joining step S5 and the inspection step S6. [Figure 10] It is a diagram for explaining the joining method of the comparative example. [Figure 11] It is a diagram for explaining the joining method of the modification example.

Mode for Carrying Out the Invention

[0010] Hereinafter, an embodiment of a method for joining substrates and a joining apparatus according to the present invention will be described based on the accompanying drawings.

[0011] First, the substrate W used in the joining apparatus 1 and the joining method will be described. The substrate W is, for example, a wafer formed of a material such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or other semiconductors.

[0012] (a) of FIG. 1 shows the first substrate W1, which is one of the two substrates to be joined, and (b) of FIG. 1 shows the second substrate W2, which is the other substrate W. In the following description, when referring to the first substrate, the symbol "W1" is attached, when referring to the second substrate, the symbol "W2" is attached, and when referring to the joined substrate obtained by bonding the first substrate W1 and the second substrate W2, the symbol "W3" is attached. When the first substrate W1, the second substrate, and the joined substrate W3 are not distinguished, the symbol "W" is simply attached.

[0013] The first substrate W1 has surfaces 11 and back surface 12 that are generally parallel to each other. On the surface 11 of the first substrate W1, a plurality of streets 13 that intersect each other are used as division planned lines, and a plurality of regions partitioned by the division planned lines are formed in a grid pattern. In each of the partitioned regions, devices 14 such as IC (Integrated Circuit), LSI (Large Scale Integrated circuit), and MEMS (Micro Electro Mechanical Systems) are formed. Note that reference numeral 15 is a notch indicating the crystal orientation of the first substrate W1.

[0014] An alignment mark M1 is formed on the first substrate W1. The alignment mark M1 serves as an alignment mark when joining the first substrate W1 and the second substrate W2.

[0015] The alignment mark M1 is formed, for example, on the outer peripheral portion 16 of the first substrate W1 by exposure using an exposure apparatus (not shown). Specifically, the outer peripheral portion 16 includes the outer peripheral surface 16a (that is, the side surface of the first substrate W1) and the region from the outer peripheral surface 16a to a position radially inward by a predetermined distance, and is a region where no device 14 is formed. The alignment mark M1 can be formed, for example, at the edge portion between the surface 11 and the outer peripheral surface 16a. By forming the alignment mark M1 at the edge portion, an exposure apparatus used when forming the device 14 on the surface 11 of the first substrate W1 can be used, and the alignment mark M1 that can be detected from the outer peripheral surface 16a side (that is, from the side of the substrate) can be formed on the surface 11 side of the first substrate W1. As a result, a new apparatus for forming the alignment mark M1 becomes unnecessary. By using exposure technology, the alignment mark M1 can be accurately formed on the first substrate W1 having a thickness on the order of several tens to several hundreds of μm. Specifically, the alignment mark M1 can be formed with high precision on the order of nm by exposure.

[0016] Here, an example is shown in which the alignment mark M1 is formed exposed on the outer peripheral surface 16a of the outer peripheral portion 16 of the first substrate W1. However, the position in which the alignment mark M1 is formed is not limited to this, and the alignment mark M1 may also be formed inside the outer peripheral portion 16 of the first substrate W1. That is, the alignment mark M1 may not be exposed on the outer peripheral surface 16a, but may be formed inside the first substrate W1 at a position close to the outer peripheral surface 16a. In this case, the position of the alignment mark M1 is a position that can be detected by transmitted light from the outer peripheral surface 16a side (i.e., from the side of the substrate).

[0017] The second substrate W2 may have the same configuration as the first substrate W1. That is, the second substrate W2 also has a surface 21 and a back surface 22 that are generally parallel to each other. On the surface 21 of the second substrate W2, multiple intersecting streets 23 are designated as dividing lines, and multiple regions are formed in a grid pattern along these dividing lines. Devices 24 such as ICs, LSIs, and MEMS are formed in each of these divided regions. Reference numeral 25 denotes a notch indicating the crystal orientation of the second substrate W2.

[0018] Alignment marks M2 are formed on the second substrate W2. The alignment marks M2 serve as markers for positioning when joining the second substrate W2 and the first substrate W1.

[0019] Alignment marks M2 are formed on the outer periphery 26 of the second substrate W2 by exposure using, for example, an exposure apparatus (not shown), similar to the alignment marks M1 of the first substrate W1. The outer periphery 26 includes the outer periphery surface 26a (i.e., the side surface of the second substrate W2) and the region extending radially inward from the outer periphery surface 26a at a predetermined distance, and is a region where the device 24 is not formed.

[0020] Here, an example is shown in which the alignment mark M2 is formed exposed on the outer peripheral surface 26a of the outer peripheral portion 26 of the second substrate W2. However, the position in which the alignment mark M2 is formed is not limited to this, and the alignment mark M2 may also be formed inside the outer peripheral portion 26 of the second substrate W2. That is, the alignment mark M2 may not be exposed on the outer peripheral surface 26a, but may be formed inside the second substrate W2 at a position close to the outer peripheral surface 26a.

[0021] Although not shown in the diagram, a laminate is formed on the surface 11 side of the first substrate W1 and on the surface 21 side of the second substrate W2, with multiple thin films stacked on top of each other. The laminate includes conductive films that function as electrodes, wiring, terminals, etc., and insulating films that function as interlayer insulating films.

[0022] Figure 2(a) is a diagram illustrating the joining of the first substrate W1 and the second substrate W2, and Figure 2(b) is a perspective view showing an example of a joined substrate W3. By placing the surface 11 of the first substrate W1 and the surface 21 of the second substrate W2 facing each other and joining the substrates using a joining device 1 described later, a joined substrate W3 is manufactured by bonding the first substrate W1 and the second substrate W2 together.

[0023] Furthermore, the device 14 on the first substrate W1 and the device 24 on the second substrate W2 are equipped with electrode pads and through electrodes connected to the electrode pads, and the through electrodes enable the connection of electrodes by bonding the substrates together. In other words, the first substrate W1 and the second substrate W2 are substrates in which devices have through electrodes (TSV: Through Silicon Via).

[0024] The bonding of the first substrate W1 and the second substrate W2 is performed by the bonding apparatus 1, but once the substrates are bonded together, it is difficult to redo the process. Therefore, it is preferable to improve the accuracy of the alignment of the substrates before bonding. Accordingly, the bonding apparatus 1 has a configuration that can suppress misalignment between the substrates.

[0025] Figure 3 is a schematic perspective view showing an example of the joining device 1. In the following description, the X-axis direction is a single direction in the horizontal plane. The Y-axis direction is perpendicular to the X-axis direction in the horizontal plane. The Z-axis direction is perpendicular to both the X-axis and Y-axis directions.

[0026] The joining device 1 comprises, as its main components, a base 30, a cassette storage section 40, a transport unit 50, a temporary storage table 60, a joining unit 100, and a control unit 200.

[0027] The cassette housing section 40 is provided on the base 30 at one end in the X-axis direction and includes two first housing spaces 40a and a second housing space 40b arranged in the Y-axis direction. For example, a cassette C1 containing a first substrate W1 and a second substrate W2 before bonding is placed in the first housing space 40a. For example, a cassette C2 containing a bonded substrate W3 after bonding is placed in the second housing space 40b. Cassettes C1 and C2 can each accommodate multiple substrates W.

[0028] The transport unit 50 is provided adjacent to the cassette storage section 40 and loads and unloads substrates W to and from each cassette C1 and C2. The transport unit 50 comprises a base 51 and a pivotable arm 52 supported on the base 51. The base 51 is configured to be movable in the X-axis and Y-axis directions, for example. The direction in which the base 51 can move is arbitrary, as long as the loading and unloading of substrates W can be achieved by the movement of the base 51 and the operation of the arm 52. Furthermore, if the loading and unloading of substrates W can be achieved by the operation of the arm 52 alone, the base 51 may not move. In this embodiment, the transport unit 50 is made movable in the X-axis and Y-axis directions by a known moving mechanism (not shown) composed of, for example, a guide rail, a ball screw, a pulse motor, etc.

[0029] The transport unit 50 transports the substrate W between the cassette storage section 40, the temporary storage 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 storage table 60, then unloads the first substrate W1 and the second substrate W2 from the temporary storage table 60 and loads them onto the bonding unit 100. Alternatively, it unloads the first substrate W1 and the second substrate W2 before bonding from the cassette C1 and loads them onto the bonding unit 100. The transport unit 50 also unloads the bonded substrate W3 produced by the bonding unit 100 from the bonding unit 100 and loads it onto the cassette C2 in the second storage space 40b.

[0030] The temporary storage table 60 holds the transported first substrate W1 and second substrate W2 by suction, by operating a suction source (not shown). The temporary storage table 60 is also equipped with an imaging mechanism 70 for imaging the transported substrate W.

[0031] The bonding unit 100 includes a chamber 102 capable of forming a sealed processing space inside. The first substrate W1 and the second substrate W2, which have been transported by the transport unit 50, are placed inside the chamber 102, and the pressure inside the chamber 102 is reduced. The bonding unit 100 then bonds the first substrate W1 and the second substrate W2 inside the reduced-pressure chamber 102.

[0032] Figure 4 is a schematic diagram showing an example of a bonding unit 100. Specifically, the bonding unit 100 includes a first holding part 105 for holding the first substrate W1, a second holding part 110 for holding the second substrate W2, a detection unit 120 for detecting alignment marks M1 and M2 formed on the first substrate W1 and the second substrate W2, a moving unit 130 for moving the detection unit 120, and a positioning unit 140 for positioning the first substrate W1 and the second substrate W2 relative to each other.

[0033] The first holding part 105 is a holding part that holds the first substrate W1 by suction, and is provided so as to face the second holding part 110, and is supported so as to be able to move up and down vertically (in the Z-axis direction) with its holding surface facing downward. The first substrate W1 is held by the first holding part 105 with the bonding surface (i.e., surface 11) with the second substrate W2 facing downward. The lower surface of the first holding part 105 is a holding surface formed from, for example, porous ceramic, and the first substrate W1 is held by suction by operating a suction source (not shown).

[0034] Furthermore, an adjustment unit 106 is provided above the first holding unit 105 for adjusting 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.

[0035] Furthermore, a through-hole is formed above the adjustment section 106, penetrating the chamber 102 in the Z-axis direction, and a shaft 107 is inserted into this through-hole. The shaft 107 can be raised and lowered vertically together with the first holding section 105 and the adjustment section 106, for example, by a lifting mechanism 109. As the shaft 107 moves up and down, the first holding section 105 and the second holding section 110 move closer together or further apart. A cylindrical bellows joint 108 is provided around the through-hole, surrounding it.

[0036] The second holding portion 110 is a holding portion that adsorbs and holds the second substrate W2, and is provided so as to face the first holding portion 105, and is supported below the chamber 102 with the bonding surface (i.e., surface 21) with the first substrate W1 facing upward.

[0037] In this embodiment, the adjustment part 106 is provided on the first holding part 105 side, but this adjustment part 106 may also be provided on the second holding part 110 side. That is, the second holding part 110 may be provided so as to be movable in the X-axis direction or the Y-axis direction by the adjustment part 106, or so as to be rotatable around the Z-axis. Also, in this embodiment, the first holding part 105 is configured to move up and down together with the shaft 107, causing the first holding part 105 and the second holding part 110 to move closer to or further away from each other, but the second holding part 110 may be configured to move up and down, causing it to move closer to or further away from the first holding part 105.

[0038] The positioning unit 140 is composed of an adjustment unit 106, a shaft 107, a bellows joint 108, and a lifting mechanism 109 provided on the side of the first holding unit 105, and / or a configuration of an adjustment unit 106, a shaft 107, a bellows joint 108, and a lifting mechanism 109 provided on the side of the second holding unit 110. As will be described in detail later, the positioning unit 140 positions the first substrate W1 and the second substrate W2 relative to each other based on the alignment marks M1 and M2 detected by the detection unit 120.

[0039] The detection unit 120 detects alignment marks M1 and M2 provided on the first substrate W1 and the second substrate W2, respectively. The detection unit 120 is a detection device capable of detecting alignment marks M1 and M2, such as an optical microscope or an electron microscope. For example, the detection unit 120 may be a scanning electron microscope (SEM), in which case the alignment marks M1 and M2 formed with high precision by exposure can be observed with nanometer-order accuracy. Alternatively, the detection unit 120 may be a detection device capable of detecting alignment marks M1 and M2 using Raman spectroscopy or infrared spectroscopy.

[0040] The detection unit 120 is positioned laterally to the first substrate W1 and the second substrate W2, when viewed from the opposing direction (in this case, the Z-axis direction) in which the first substrate W1 and the second substrate W2 face each other. That is, the detection unit 120 detects alignment marks M1 and M2 from the side of the first substrate W1 and the second substrate W2. In the initial state, the detection unit 120 is positioned at a height that allows it to detect the second substrate W2 held by the second holding part 110.

[0041] The moving unit 130 moves the detection unit 120 along the X-axis and Y-axis directions at a lateral position of the first substrate W1 and the second substrate W2. The configuration of the moving unit 130 may vary, and for example, it may be a known ball screw type moving unit. The moving unit 130 may also be configured to further move the detection unit 120 along the Z-axis direction. The moving unit 130 moves the detection unit 120 to a position where alignment marks M1 and M2 can be detected.

[0042] The moving unit 130 only needs to change the relative positions of the detection unit 120 and the first substrate W1 and the second substrate W2. For example, it may move the first substrate W1 and the second substrate W2 (i.e., the first holding part 105 and the second holding part 110) relative to the detection unit 120.

[0043] Figure 5 is a flowchart showing an example of a joining method for joining a first substrate W1 and a second substrate W2. The joining method includes a first holding step S1 in which the first substrate W1 is held by a first holding part 105, a second holding step S2 in which the second substrate W2 is held by a second holding part 110, a detection step S3 in which alignment marks M1 and M2 formed on the first substrate W1 and the second substrate W2 are detected, a positioning step S4 in which the first substrate W1 and the second substrate W2 are positioned relative to each other based on the alignment marks M1 and M2 detected in the detection step S3, a joining step S5 in which the first substrate W1 and the second substrate W2 positioned in the positioning step S4 are joined, and an inspection step S6 in which the positioning of the first substrate W1 and the second substrate W2 is checked. Each of these steps is performed by a control unit 210. In this specification, plasma activation treatment is described as one example of the treatment in bonding step S5, but the method is not limited to this, and the first substrate W1 and the second substrate W2 may be bonded by any bonding treatment.

[0044] In the bonding method according to the embodiment, before executing the first holding step S1, the control unit 210 supplies 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 perform a plasma activation treatment to activate the respective bonding surfaces in order to bond the first substrate W1 and the second substrate W2. By performing such a plasma activation treatment, surface impurities such as organic matter adsorbed on the surfaces of the first substrate W1 and the second substrate W2 are removed, and clean surfaces are exposed. Furthermore, hydroxyl groups (OH groups) are formed on the exposed clean surfaces. The first substrate W1 and the second substrate W2, which have undergone such plasma activation treatment, are then housed in the cassette C1 of the first storage space 40a.

[0045] As shown in Figure 6, in the first holding step S1, the control unit 210 causes the first substrate W1 to be held by the first holding unit 105. That is, the control unit 210 transports the first substrate W1 to the first holding unit 105 using the transport unit 50, orients the surface that is joined to the second substrate W2 downwards, and causes the surface opposite to that joining surface to be held by the first holding unit 105.

[0046] As shown in Figure 7, in the second holding step S2, the control unit 210 causes the second substrate W2 to be held by the second holding unit 110. That is, the control unit 210 transports the second substrate W2 to the second holding unit 110 using the transport unit 50, orients the surface that is joined to the first substrate W1 upwards, and causes the surface opposite to that joined surface to be held by the second holding unit 110. Note that the order of the first holding step S1 and the second holding step S2 may be reversed.

[0047] As shown in Figure 8, in detection step S3, the detection unit 120 detects alignment marks M1 and M2 formed on the outer periphery portions 16 and 26 of the first substrate W1 and the second substrate W2 from a lateral position that does not overlap with the first substrate W1 and the second substrate W2 when viewed from the opposing direction in which the first substrate W1 and the second substrate W2 face each other.

[0048] More specifically, in detection step S3, the control unit 210 controls the positioning unit 140 to adjust the positions of the first holding part 105 and the second holding part 110 so that the detection unit 120 can detect the alignment marks M1 and M2. First, the control unit 210 adjusts the position of the second holding part 110, thereby allowing the detection unit 120 to detect the alignment marks M2 formed on the second substrate W2. Next, the control unit 210 lowers the first holding part 105 to a predetermined height, bringing it closer to the second holding part 110. The control unit 210 adjusts the position of the first holding part 105 by moving it in the X-axis direction and / or Y-axis direction, or by rotating it around the Z-axis, so that the detection unit 120 can detect the alignment marks M1 formed on the first substrate W1. In this way, the detection unit 120 detects the alignment marks M1 and M2 formed on the outer periphery portions 16 and 26 of the first substrate W1 and the second substrate W2 from a lateral position.

[0049] In positioning step S4, the control unit 210 adjusts the positions of the first holding part 105 and the second holding part 110 by controlling the positioning unit 140 based on the alignment marks M1 and M2 detected in detection step S3, thereby positioning the first substrate W1 and the second substrate W2 relative to each other. In positioning step S4, the final alignment of the first substrate W1 and the second substrate W2 is performed before the bonding step S5.

[0050] More specifically, in positioning step S4, the control unit 210 relative to the first substrate W1 and the second substrate W2 such that the positions of the alignment marks M1 and M2 in the X-axis and Y-axis directions coincide, and the positions of the alignment marks M1 and M2 in the rotational direction around the Z-axis of the first substrate W1 and the second substrate W2 coincide. Note that "coincidence" does not mean perfect coincidence, and there may be a predetermined amount of misalignment. The control unit 210 may then repeatedly execute positioning step S4 until the predetermined amount of misalignment falls within a threshold.

[0051] In positioning step S4, the control unit 210 positions the first substrate W1 and the second substrate W2 relative to each other while the detection unit 120 is detecting alignment marks M1 and M2, bringing the first substrate W1 and the second substrate W2 very close together. The control unit 210 may also position the first substrate W1 and the second substrate W2 relative to each other and bring them into contact while the detection unit 120 is detecting alignment marks M1 and M2.

[0052] In this way, since the detection unit 120 detects alignment marks M1 and M2 from a lateral position, the first substrate W1 and the second substrate W2 can be brought very close together or even in contact with each other while the detection unit 120 is detecting alignment marks M1 and M2. Therefore, the accuracy of the alignment between the first substrate W1 and the second substrate W2 can be further improved.

[0053] As shown in Figure 9, in bonding step S5, the control unit 210 presses the first substrate W1 and the second substrate W2 together by controlling the lifting mechanism 109, thereby bonding the substrates together. More specifically, before executing bonding step S5, the control unit 210 performs a depressurization process to reduce the internal space of the chamber 102, creating a high vacuum state inside the chamber 102. Bonding step S5 is performed in a high vacuum state, generating a bonded substrate W3 by pressing the first substrate W1 and the second substrate W2 together.

[0054] Since the detection unit 120 is positioned laterally on the first substrate W1 and the second substrate W2, the bonding step S5 may be performed while the detection unit 120 is detecting alignment marks M1 and M2.

[0055] In inspection step S6, after bonding step S5, the detection unit 120 inspects the positioning of the first substrate W1 and the second substrate W2. This allows for verification of whether the bonded substrate W3 has been produced without any misalignment. Furthermore, since detection step S3 and inspection step S6 can be performed using a common detection unit 120, the apparatus can be simplified.

[0056] Incidentally, the bonded substrate W3 produced in bonding step S5 is in a provisionally bonded state, and the final bonding is performed by an annealing apparatus (not shown).

[0057] First, let's explain the temporary bonding. In the bonded substrate W3 after the bonding step S5, hydrogen atoms (H) of the OH groups formed on the surface 11 side of the first substrate W1 form hydrogen bonds with oxygen atoms (O) of the OH groups formed on the surface 21 side of the second substrate W2. Similarly, hydrogen atoms (H) of the OH groups formed on the surface 21 side of the second substrate W2 form hydrogen bonds with oxygen atoms (O) of the OH groups formed on the surface 11 side of the first substrate W1. Due to these hydrogen bonds, the first substrate W1 and the second substrate W2 attract each other and enter a temporary bonded state.

[0058] After the initial bonding, the control unit 210 releases the air from inside the chamber 102, releases the suction holding of the first substrate W1 by the first holding unit 105, and releases the suction holding of the second substrate W2 by the second holding unit 110. Then, the control unit 210 transports the generated bonded substrate W3 to the cassette C2 using the transport unit 50 and places it in the cassette C2.

[0059] The provisionally bonded substrate W3 is heat-treated by an annealing apparatus, causing a dehydration condensation reaction at the bonding surface between the first substrate W1 and the second substrate W2. Specifically, at the bonding surface between the first substrate W1 and the second substrate W2, water (H2O) is lost from the OH groups, forming a covalent bond via oxygen atoms (O). This further improves the bonding strength between the first substrate W1 and the second substrate W2, resulting in the final bonded substrate W3.

[0060] The joining method described in the above-described embodiment can be realized by executing a pre-prepared control program on a computer. This control program is stored in a computer-readable storage medium and executed by reading it from the storage medium. This control program may also be provided in the form of a non-transient storage medium such as flash memory, or it may be provided via a network such as the Internet. The computer that executes this control program may be included in the control unit 200, or it may be included in an electronic device such as a smartphone, tablet terminal, or personal computer that can communicate with the control unit 200, or it may be included in a server device that can communicate with these control units 200 and electronic devices.

[0061] (Comparative example) Next, while explaining the substrate bonding method of the comparative example, the effects of the substrate bonding method of the embodiment described above will be described in detail.

[0062] Figure 10 is a diagram illustrating the bonding method of the comparative example, and specifically shows the bonding unit 100 of the comparative example. In the comparative example, alignment marks M1 and M2 are formed on the surfaces 11 and 21 of the first substrate W1 and the second substrate W2, respectively.

[0063] The comparative example detection unit 120 includes a first detection unit 121 for detecting alignment marks M1 formed on the first substrate W1, and a second detection unit 122 for detecting alignment marks M2 formed on the second substrate W2. When detecting alignment marks M1 and M2, the first detection unit 121 and the second detection unit 122 are positioned in the space between the first substrate W1 and the second substrate W2, and detect the alignment marks M1 and M2 from opposing directions of the first substrate W1 and the second substrate W2.

[0064] In the comparative example bonding method, when the detection step S3 and positioning step S4 are performed, the detection unit 120 is moved by the moving unit 130 and placed in the space between the first substrate W1 and the second substrate W2. Then, when the bonding step S5 is performed, the detection unit 120 is moved out of the space between the first substrate W1 and the second substrate W2.

[0065] In this comparative example of a joining method, since the detection unit 120 is positioned in the space between the first substrate W1 and the second substrate W2 during the detection step S3 and the positioning step S4, there is a risk that misalignment may occur between the time the detection unit 120 is retracted and the first substrate W1 and the second substrate W2 are brought close together and into contact, from the state in which the first substrate W1 and the second substrate W2 were aligned in the positioning step S4.

[0066] In contrast, in the bonding method of the embodiment described above, the alignment marks M1 and M2 used for positioning are formed on the outer periphery 16 and 26 of the first substrate W1 and the second substrate W2 by exposure technology. Then, in the detection step S3, the alignment marks M1 and M2 are detected from a position that does not overlap the substrate when viewed from the opposing direction of the substrates. Therefore, in the positioning step S4, with the alignment marks M1 and M2 detected, the first substrate W1 and the second substrate W2 can be brought very close together, or the first substrate W1 and the second substrate W2 can be brought into contact. As a result, the accuracy of the positioning of the first substrate W1 and the second substrate W2 can be improved compared to the bonding method of the comparative example.

[0067] (modified version) Figure 11 is a diagram illustrating a modified joining method. In the modified example, multiple alignment marks M1 and M2 are formed on the outer periphery portions 16 and 26 of the first substrate W1 and the second substrate W2, respectively. In this example, three alignment marks M1 and M2 are formed on the outer periphery portions 16 and 26 of the first substrate W1 and the second substrate W2, respectively, at approximately equal intervals (120-degree intervals). Note that two alignment marks M1 and M2 may be formed, or four or more may be formed.

[0068] Multiple detection units 120 are provided, corresponding to the alignment marks M1 and M2 formed on each substrate W1 and W2, respectively. In this case, since three pairs of alignment marks M1 and M2 are formed, three detection units 120 are provided.

[0069] In the modified example detection step S3, the corresponding alignment marks M1 and M2 are detected by each detection unit 120. Then, in the positioning step S4, the first substrate W1 and the second substrate W2 are positioned relative to each other based on the multiple alignment marks M1 and M2 detected in the detection step S3. Since the first substrate W1 and the second substrate W2 are aligned based on the multiple alignment marks M1 and M2, the accuracy of the alignment between the first substrate W1 and the second substrate W2 can be further improved.

[0070] Although one embodiment of the present invention and its variations have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various variations or modifications can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any way without departing from the spirit of the invention.

[0071] This specification includes at least the following: The components and other elements corresponding to those in the embodiments described above are shown in parentheses as examples, but are not limited thereto.

[0072] (1) A method for joining substrates, which involves joining a first substrate (first substrate W1) and a second substrate (second substrate W2), A first holding step (first holding step S1) in which the first substrate is held by the first holding part (first holding part 105), A second holding step (second holding step S2) is performed in which the second substrate is held by a second holding part (second holding part 110) which is positioned opposite to the first holding part, A detection step (detection step S3) is performed to detect alignment marks (alignment marks M1, M2) formed on the outer periphery (outer periphery 16, 26) of the first substrate and the second substrate from a position that does not overlap the first substrate and the second substrate when viewed from the opposing direction in which the first substrate and the second substrate face each other. A positioning step (positioning step S4) is performed to position the first substrate and the second substrate relative to each other based on the alignment marks detected in the detection step, The system includes a bonding step (bonding step S5) for bonding the first substrate and the second substrate that were positioned in the positioning step, Method for joining circuit boards.

[0073] According to (1), alignment marks used for positioning are formed on the outer periphery of each substrate, and the detection step detects the alignment marks from a position that does not overlap with the substrate when viewed from the opposite direction of the substrate. With this configuration, the positioning step can bring the first substrate and the second substrate very close together, or even bring the first substrate and the second substrate into contact, while the alignment marks are being detected. Therefore, the accuracy of positioning the first substrate and the second substrate can be improved.

[0074] (2) A method for joining substrates as described in (1), The detection step involves detecting the alignment marks exposed on the outer peripheral surfaces (outer peripheral surface 16a) of the outer peripheral portions of the first substrate and the second substrate. Method for joining circuit boards.

[0075] According to (2), the detection unit can detect alignment marks exposed on the outer surface of the substrate from the outer surface side.

[0076] (3) A method for joining substrates as described in (1), The detection step involves detecting the alignment marks located inside the outer periphery of the first and second substrates. Method for joining circuit boards.

[0077] According to (3), the detection unit can detect alignment marks located inside the outer periphery of the substrate from the outer surface side.

[0078] (4) A method for joining substrates as described in any of (1) to (3), The positioning step involves positioning the first substrate and the second substrate relative to each other and bringing them into contact, while detecting the alignment marks formed on the first substrate and the second substrate by the detection step. Method for joining circuit boards.

[0079] According to (4), since the first substrate and the second substrate are brought into contact while the alignment marks are being detected, the accuracy of the alignment between the first substrate and the second substrate can be further improved.

[0080] (5) A method for joining substrates as described in any of (1) to (4), After the bonding step, the system further includes an inspection step (inspection step S6) in which the alignment of the first substrate and the second substrate is inspected by a detection unit (detection unit 120) that performs the detection step. Method for joining circuit boards.

[0081] According to (5), since the detection of alignment marks and the inspection of the substrate alignment after bonding can be performed using a common detection unit, the bonding apparatus can be simplified.

[0082] (6) A method for joining substrates as described in any of (1) to (5), Multiple alignment marks are formed on the outer periphery of the first substrate and the second substrate, respectively. The positioning step involves positioning the first substrate and the second substrate relative to each other based on the plurality of alignment marks detected in the detection step. Method for joining circuit boards.

[0083] According to (6), the first substrate and the second substrate are aligned based on multiple alignment marks, which further improves the accuracy of the alignment between the first substrate and the second substrate.

[0084] (7) A substrate bonding apparatus (bonding apparatus 1) for bonding a first substrate (first substrate W1) and a second substrate (second substrate W2), The first holding portion (first holding portion 105) that holds the first substrate, A second holding portion (second holding portion 110) is positioned opposite the first holding portion and holds the second substrate, A detection unit (detection unit 120) detects alignment marks (alignment marks M1, M2) formed on the outer periphery (outer periphery 16, 26) of the first substrate and the second substrate from a position that does not overlap the first substrate and the second substrate when viewed from the opposing direction in which the first substrate and the second substrate face each other. The system includes a positioning unit (positioning unit 140) that positions the first substrate and the second substrate relative to each other based on the alignment marks detected by the detection unit. A device for bonding circuit boards.

[0085] According to (7), alignment marks used for positioning are formed on the outer periphery of each substrate, and the detection unit detects the alignment marks from a position that does not overlap with the substrate when viewed from the opposite direction of the substrate. With this configuration, the positioning unit can bring the first substrate and the second substrate very close together, or even bring the first substrate and the second substrate into contact, while detecting the alignment marks. Therefore, the accuracy of positioning between the first substrate and the second substrate can be improved.

[0086] (8) A substrate bonding apparatus as described in (7), The detection unit inspects the alignment of the first substrate and the second substrate in their bonded state. A device for bonding circuit boards.

[0087] According to (8), since the detection of alignment marks and the inspection of the substrate alignment after bonding can be performed using a common detection unit, the bonding apparatus can be simplified. [Explanation of Symbols]

[0088] 1 Bonding equipment 16, 26 Outer perimeter 16a, 26a outer surface 105 1st holding part 110 Second holding part 120 detection units 140 Positioning Unit M1, M2 alignment marks W1 First Circuit Board W2 Second Board S1 First holding step S2 Second holding step S3 Detection Step S4 Positioning step S5 Joining Step S6 Inspection Step

Claims

1. A method for joining substrates, which involves joining a first substrate and a second substrate, A first holding step in which the first substrate is held in the first holding part, A second holding step in which the second substrate is held by a second holding portion arranged opposite to the first holding portion, A detection step of detecting alignment marks formed on the outer periphery of the first substrate and the second substrate from a position that does not overlap the first substrate and the second substrate when viewed from the opposing direction in which the first substrate and the second substrate face each other, A positioning step in which the first substrate and the second substrate are positioned relative to each other based on the alignment marks detected in the detection step, The system includes a bonding step of bonding the first substrate and the second substrate that were positioned in the positioning step. Method for joining circuit boards.

2. A method for joining substrates according to claim 1, The detection step involves detecting the alignment marks exposed on the outer peripheral surfaces of the outer peripheral portions of the first substrate and the second substrate. Method for joining circuit boards.

3. A method for joining substrates according to claim 1, The detection step involves detecting the alignment marks located inside the outer periphery of the first and second substrates. Method for joining circuit boards.

4. A method for joining substrates according to any one of claims 1 to 3, The positioning step involves positioning the first substrate and the second substrate relative to each other and bringing them into contact, while detecting the alignment marks formed on the first substrate and the second substrate by the detection step. Method for joining circuit boards.

5. A method for joining substrates according to any one of claims 1 to 3, The invention further includes an inspection step in which, after the bonding step, the alignment of the first substrate and the second substrate is inspected by a detection unit that performs the detection step. Method for joining circuit boards.

6. A method for joining substrates according to any one of claims 1 to 3, Multiple alignment marks are formed on the outer periphery of the first substrate and the second substrate, respectively. The positioning step involves positioning the first substrate and the second substrate relative to each other based on the plurality of alignment marks detected in the detection step. Method for joining circuit boards.

7. A substrate bonding apparatus for bonding a first substrate and a second substrate, A first holding portion that holds the first substrate, A second holding portion is positioned opposite the first holding portion and holds the second substrate, A detection unit that detects alignment marks formed on the outer periphery of the first substrate and the second substrate from a position that does not overlap the first substrate and the second substrate when viewed from the opposing direction in which the first substrate and the second substrate face each other, The system includes a positioning unit that positions the first substrate and the second substrate relative to each other based on the alignment marks detected by the detection unit. A device for bonding circuit boards.

8. A substrate bonding apparatus according to claim 7, The detection unit inspects the alignment of the first substrate and the second substrate in their joined state. A device for bonding circuit boards.

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