Bonding system and bonding method

Abstract

In the present invention, a joining system comprises: a first joining device (1) that, in a state in which the joining portions of each of a plurality of substrates have been activated under reduced pressure, temporarily joins the plurality of substrates to each other by causing the joining parts of the plurality of substrates to contact each other; second joining devices (2A, 2B) that, under reduced pressure, perform main joining the plurality of substrates to each other by raising the temperature of the plurality of temporarily joined substrates to the main joining temperature, which is higher than the temporary joining temperature, and applying pressure to the plurality of substrates in the direction in which the substrates approach each other; and a conveying device (84) that, in a state of reduced pressure, conveys the plurality of substrates that have been temporarily joined to each other from the first joining device (1) to the second joining devices (2A, 2B).

Description

[Technical field]

[0001] The present invention relates to a bonding system and a bonding method. [Background technology]

[0002] A room temperature bonding method for silicon wafers has been proposed in which, before bonding two silicon wafers together, the bonding surfaces of the two silicon wafers are irradiated with an inert gas ion beam or an inert gas fast atom beam in a vacuum at room temperature to perform sputter etching (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-92702 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of bonding method, if the arithmetic mean roughness (Ra) of the surface of the bonding portion is 0.5 nm or less, the objects to be bonded can be firmly bonded together without gaps by the attractive force of intermolecular forces of the activated bonding surface even when the temperature of the objects to be bonded is maintained at room temperature (about 25°C). However, since the Ra of the surface of the bonding portion made of metal is about several nm, it is difficult to firmly bond the bonding portions together without gaps while maintaining the temperature of the objects to be bonded at room temperature. Furthermore, only the protruding parts of the surfaces of the bonding portions are bonded together, and gaps are generated in places other than the protruding parts, so that the bonding cannot be applied to so-called sealing bonding and the bonding strength is low. For this reason, when the bonding portion is made of metal, it is necessary to bond the objects to be bonded by applying pressure to the objects to be bonded in a direction in which they approach each other while the bonding portions of the objects to be bonded are in contact with each other and maintaining the temperature of the objects to be bonded in a heated state for a certain period of time, utilizing the solid-phase diffusion of the metal that forms the bonding portion. In this way, by applying heat and pressure to the objects to be bonded for a certain period of time, the metal atoms that form the bonding portion become easier to move, and the pressurized metal atoms move into the gaps generated between the bonding portions that are in contact with each other. This allows the joints to be firmly joined together without any gaps.

[0005] However, when the objects are bonded together while being maintained at a relatively high temperature of 200° C. or higher, there is a risk that the positional accuracy of the bonded objects may decrease due to the influence of thermal distortion.

[0006] The present invention has been made in consideration of the above-mentioned reasons, and aims to provide a joining system and a joining method that can firmly join multiple objects to be joined while suppressing positional misalignment between the multiple objects to be joined. [Means for solving the problem]

[0007] In order to achieve the above object, the joint system according to the present invention comprises: A joining system for joining a plurality of workpieces to each other, comprising: a first bonding device that performs a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by bringing the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of the two bonding portions selected from the bonding portions of the multiple objects to be bonded to each other is activated; a second bonding device for performing a final bonding step of heating the plurality of objects temporarily bonded to each other to a final bonding temperature, which is a temperature higher than the temporary bonding temperature at the time of the temporary bonding, under reduced pressure and applying pressure to the plurality of objects in a direction in which they approach each other, thereby final bonding the plurality of objects to each other; a conveying device that conveys the plurality of workpieces temporarily joined to each other from the first joining device to the second joining device while maintaining a reduced pressure state, The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, In the main joining step, main joining is performed on the first joining portion and the second joining portion that are the same as the first joining portion and the second joining portion that are temporarily joined in the temporary joining step, The temperature difference between the start and end of pressure application in the temporary bonding step and the main bonding step is 100° C. or less. do.

[0008] A bonding method according to another aspect of the present invention comprises: A method for joining a plurality of objects to be joined, comprising the steps of: a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by contacting the bonding portions of the multiple objects to be bonded with each other under reduced pressure while at least one of the two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a final bonding process in which the temperature of the plurality of objects to be bonded temporarily to each other is heated to a final bonding temperature, which is a temperature higher than the temporary bonding temperature at the time of the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby final bonding the plurality of objects to be bonded together; The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, In the main joining step, main joining is performed on the first joining portion and the second joining portion that are the same as the first joining portion and the second joining portion that are temporarily joined in the temporary joining step, The temperature difference between the start and end of pressure application in the temporary bonding step and the main bonding step is 100° C. or less. do. Effect of the Invention

[0009] According to the present invention, after the activation process is performed on the multiple objects to be bonded, the multiple objects are temporarily bonded together by contacting the bonding portions of the multiple objects to each other under reduced pressure. Then, under reduced pressure, the temperature of the multiple objects to be bonded is heated to a permanent bonding temperature that is higher than the temporary bonding temperature at the time of temporary bonding, and pressure is applied to the multiple objects to be temporarily bonded together in a direction in which they approach each other, thereby permanently bonding the multiple objects to be bonded together. This allows the multiple objects to be temporarily bonded at a relatively low temperature that maintains the positional accuracy of the objects to be bonded together and is not affected by thermal distortion, and then the temperature of the multiple objects to be bonded can be increased and pressure can be applied. Therefore, the two objects to be bonded can be firmly bonded together without gaps while suppressing the positional deviation between the multiple objects to be bonded. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a bonding system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic front view of a first joining device according to the embodiment. [Figure 3A] FIG. 2 is a schematic side view of a portion of the first joining device according to the embodiment. [Figure 3B] FIG. 2 is a schematic plan view of a portion of a first joining device according to the embodiment. [Figure 4A] FIG. 2 is a schematic perspective view showing the vicinity of a stage and a head in the embodiment. [Figure 4B] 11A to 11C are diagrams illustrating a method for fine-tuning a head in the embodiment. [Figure 5A] FIG. 2 is a diagram showing two alignment marks provided on one of the two substrates to be joined. [Figure 5B] 13 is a diagram showing two alignment marks provided on the other of the two substrates to be joined. FIG. [Figure 6A] FIG. 2 is a schematic diagram showing a captured image of an alignment mark. [Figure 6B] FIG. 1 is a schematic diagram showing a state in which alignment marks are misaligned with each other. [Figure 7]FIG. 4 is a schematic front view of a second joining device according to the embodiment. [Figure 8A] FIG. 1 is a perspective view showing an example of an entire substrate to be bonded to one another. [Figure 8B] FIG. 8B is a perspective view of the portion enclosed by the dashed line in FIG. 8A. [Figure 9] FIG. 13 is a perspective view showing a portion of another example of substrates bonded to each other. [Figure 10] FIG. 13 is a perspective view showing a portion of another example of substrates bonded to each other. [Figure 11A] FIG. 13 is a diagram showing how two substrates are brought close to each other. [Figure 11B] FIG. 13 is a diagram showing how two substrates are temporarily bonded together. [Figure 12A] FIG. 13 is a diagram showing how two substrates are brought close to each other. [Figure 12B] FIG. 13 is a diagram showing how two substrates are temporarily bonded together. [Figure 13A] 4 is a schematic diagram showing the state of the surfaces of two bonded portions temporarily bonded to each other after a temporary bonding step according to the embodiment. FIG. [Figure 13B] 5 is a schematic diagram showing the state of the surfaces of two bonded portions bonded to each other after a main bonding step according to the embodiment. FIG. [Figure 14A] FIG. 11 is a schematic diagram showing a state in which two bonding portions are in contact with each other in a main bonding step according to the embodiment. [Figure 14B] 10A and 10B are schematic diagrams illustrating a state in which pressure is applied to two bonded portions in contact with each other in a main bonding step according to the embodiment. [Figure 14C] FIG. 13 is a schematic diagram showing a state after a main bonding step according to the embodiment. [Figure 15A] 13 is a photograph showing the appearance of substrates bonded together when the temperature of the substrates was 25° C. in this bonding process. [Figure 15B] 13 is a photograph showing the appearance of substrates bonded together when the temperature of the substrates is set to 200° C. in this bonding process. [Figure 16A] 11A and 11B are diagrams illustrating a state in which a substrate is transferred from an introduction port to a transport robot in the bonding system according to the embodiment. [Figure 16B] 11 is a diagram showing a state in which a substrate is transferred from a transport device to a load lock unit in the bonding system according to the embodiment. FIG. [Figure 17A] 11 is a diagram showing a state in which a substrate is transferred from a load lock unit to a transport device in the bonding system according to the embodiment. FIG. [Figure 17B] FIG. 4 is a diagram showing a state in which a substrate is transferred from a transport device to a first bonding device in the bonding system according to the embodiment. [Figure 18] 4 is a flowchart showing a flow of a bonding method executed by the bonding system according to the embodiment. [Figure 19A] FIG. 2 is a schematic side view of a first joining device according to the embodiment. [Figure 19B] FIG. 2 is a schematic plan view of a first joining device according to the embodiment. [Figure 20] 5 is a flowchart showing a flow of a temporary bonding process performed by the first bonding device according to the embodiment. [Figure 21A] FIG. 13 is a diagram showing how two substrates temporarily bonded to each other are transferred from a first bonding device to a transport device in the bonding system according to the embodiment. [Figure 21B] FIG. 13 is a diagram showing how the two substrates bonded together are transported by a transport device to a second bonding device in the bonding system according to the embodiment. [Figure 22] FIG. 13 is a diagram showing how, while a main bonding process is being performed in one second bonding device, two substrates that have been temporarily bonded to each other are transferred from a transport device to the other second bonding device in the bonding system of the embodiment. [Figure 23] 6 is a flowchart showing a flow of a main bonding process performed by a second bonding device according to the embodiment. [Figure 24A] FIG. 13 is a diagram showing how two bonded substrates are transferred from a transfer device to a load lock unit in the bonding system according to the embodiment. [Figure 24B] 11 is a diagram showing a state in which a substrate is transferred from a load lock unit to a transport device in the bonding system according to the embodiment. FIG. [Diagram 25] 4 is a time chart of a substrate transport, an activation process, a temporary bonding process, and a main bonding process, which are performed in the bonding system according to the embodiment. [Figure 26A] FIG. 13 is a diagram showing how two substrates are temporarily joined together. [Figure 26B] FIG. 13 is a diagram showing a state in which a further substrate is temporarily bonded to the two substrates that have already been temporarily bonded to each other. [Figure 27A] 10 is a schematic diagram showing a state in which a substrate is inserted into a cassette of a load lock unit in the bonding system according to the embodiment; FIG. [Figure 27B] FIG. 4 is a diagram showing a state in which a substrate is transported to a first bonding device in the bonding system according to the embodiment. [Figure 28A] 1 is a schematic diagram showing a state in which a substrate is transported to a load lock unit in a bonding system according to an embodiment; FIG. [Figure 28B] FIG. 4 is a diagram showing a state in which a substrate is transported to a first bonding device in the bonding system according to the embodiment. [Figure 29] 10 is a schematic diagram showing a state in which a substrate is transported to a load lock unit in the bonding system according to the embodiment; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A bonding system according to an embodiment of the present invention will be described below with reference to the drawings. In the bonding system according to this embodiment, first, a first bonding device performs an activation process on the bonding portions of a plurality of substrates under reduced pressure, and then brings the substrates into contact with each other to temporarily bond them. Next, a transport device transports the temporarily bonded substrates from the first bonding device to a second bonding device that performs the final bonding while maintaining the reduced pressure. Then, the second bonding device heats and presses the temporarily bonded substrates to permanently bond the substrates.

[0012] 1, the bonding system according to this embodiment includes introduction ports 811, 812, and 813, an ejection port 814, transport devices 82 and 84, a first bonding apparatus 1, second bonding apparatuses 2A and 2B, a control unit 9, and a load lock unit 83. The control unit 9 controls the transport devices 82 and 84, the cleaning apparatus 3, the first bonding apparatus 1, and the second bonding apparatuses 2A and 2B. The transport device 82 and the cleaning apparatus 3 are provided with HEPA (High Efficiency Particulate Air) filters (not shown). As a result, the insides of the transport device 82 and the cleaning apparatus 3 are in an atmospheric pressure environment with extremely few particles.

[0013] The transport device 82 includes a transport robot 821 having an arm with a holder at its tip that holds a substrate. The transport robot 821 can rotate to change the direction of the tip of the arm to the input ports 811, 812, 813 and the output port 814. The transport device 84 also includes a transport robot 841 having an arm with a holder at its tip that holds a substrate. The transport robot 841 can rotate to change the direction of the tip of the arm. The holder has a vacuum chuck, an electrostatic chuck, or the like, and adsorbs and holds the side of the substrate opposite to the bonding portion. The transport device 84 also transports the multiple substrates W1, W2 that have been temporarily bonded to each other in a 10 -3 The substrates W1 and W2 are transferred from the first bonding apparatus 1 to the second bonding apparatus 2A and 2B while maintaining a vacuum state higher than Pa. The load lock unit 83 has a chamber 831 and gates 832 and 833 that are provided on the peripheral wall of the chamber 831 and open and close when the substrates W1 and W2 are transferred into the chamber 831.

[0014] As shown in Fig. 2, the first bonding apparatus 1 includes a chamber 120, a stage 141, a head 142, a stage driving unit 143, a head driving unit 144, substrate heating units 1411 and 1421, a positional deviation measuring unit 150, and particle beam sources 161 and 162. In the following description, the ±Z direction in Fig. 2 is appropriately defined as the up-down direction, and the XY direction is appropriately defined as the horizontal direction. The first bonding apparatus 1 also includes covers 122A and 122B arranged in the chamber 120, and cover heating units 123A and 123B for heating the covers 122A and 122B. The covers 122A and 122B are arranged to include activation treatment areas in the activation treatment process around the stage 141 and the head 142, respectively. The cover heating units 123A and 123B are heaters fixed to the covers 122A and 122B on the side opposite to the particle beam sources 161 and 162. The chamber 120 is connected to a vacuum pump 121a via an exhaust pipe 121b and an exhaust valve 121c. When the exhaust valve 121c is opened and the vacuum pump 121a is operated, the gas in the chamber 120 is exhausted to the outside of the chamber 120 through the exhaust pipe 121b, and the air pressure in the chamber 120 is reduced (decompressed). The air pressure in the chamber 120 is 10 -5 The pressure (degree of vacuum) within the chamber 120 can be adjusted by adjusting the amount of exhaust by varying the opening / closing amount of the exhaust valve 121c.

[0015] The particle beam sources 161 and 162 are fast atom beam (FAB) sources that irradiate at least one of the joints of the substrates W and W2 with a particle beam having a preset energy, and are activation processing units having a discharge chamber 1601, an electrode 1602 disposed in the discharge chamber 1601, a beam source driving unit 1603, and a gas supply unit 1604 that supplies argon gas into the discharge chamber 1601, as shown in FIG. 3A. A FAB emission port 1601a that emits neutral atoms is provided on the peripheral wall of the discharge chamber 1601. The discharge chamber 1601 is made of a carbon material. Here, the discharge chamber 1601 is in the shape of a long box, and a plurality of FAB emission ports 1601a are arranged in a straight line along the longitudinal direction of the discharge chamber 1601. The beam source driving unit 1603 has a plasma generating unit (not shown) that generates argon gas plasma in the discharge chamber 1601, and a DC power supply (not shown) that applies a DC voltage between the electrode 1602 and the peripheral wall of the discharge chamber 1601. The beam source driving unit 1603 applies a DC voltage between the peripheral wall of the discharge chamber 1601 and the electrode 1602 while the argon gas plasma is generated in the discharge chamber 1601. At this time, argon ions in the plasma are attracted to the peripheral wall of the discharge chamber 1601. At this time, the argon ions moving toward the FAB emission port 1601a receive electrons from the peripheral wall of the discharge chamber 1601, which is made of a carbon material and is located on the outer periphery of the FAB emission port 1601a, when passing through the FAB emission port 1601a. ​​Then, the argon ions become electrically neutralized argon atoms and are emitted outside the discharge chamber 1601. In addition, the longitudinal direction of the discharge chamber 1601 of the particle beam source 161, i.e., the length in the X-axis direction, is set to a length that covers the entire X-axis direction of the substrates W1 and W2 and is longer than the length of the substrates W1 and W2 in the X-axis direction when the substrates W1 and W2 are arranged so as to overlap with each other in the Z-axis direction, as shown in FIG. 3B, for example.

[0016] Returning to FIG. 2, the covers 122A and 122B are formed of, for example, metal, and are respectively disposed around the stage 141 and the head 142 in the chamber 120. The cover heating unit 123A has, for example, an electric heater, and is disposed adjacent to the cover 122A on the -Z direction side of the cover 122A. This cover 122A is fixed to the stage 141 and moves together with the stage 141. In addition, the cover heating unit 123B also has, for example, an electric heater, and is disposed adjacent to the cover 122B on the +Z direction side of the cover 122B. This cover 122B is fixed to the head 142 and moves together with the head 142.

[0017] The stage 141 and the head 142 are disposed in the chamber 120 so as to face each other in the vertical direction and so as to be positioned vertically below the head 142. The stage 141 is a first object holder that supports the substrate W1 on its upper surface, and the head 142 is a second object holder that supports the substrate W2 on its lower surface. The stage 141 and the head 142 are formed of a light-transmitting material such as light-transmitting glass. The stage 141 and the head 142 are provided with electrostatic chucks (not shown) that hold the substrates W1 and W2. The electrostatic chucks are provided in regions of the stage 141 and the head 142 that face the peripheries of the substrates W1 and W2 when the substrates W1 and W2 are supported by the stage 141 and the head 142, for example. The electrostatic chucks are annular and have terminal electrodes arranged along the peripheries of the stage 141 and the head 142, respectively, and linear electrodes that are electrically connected to the terminal electrodes at their base ends. The terminal electrode and the multiple electrode elements are formed of a transparent conductive film containing a transparent conductive material such as ITO. The electrostatic chuck attracts and holds the substrates W1 and W2 when a voltage is applied by a chuck driver (not shown). The upper surface of the stage 141 and the lower surface of the head 142 may be roughened in consideration of the case where the contact surfaces of the substrates W1 and W2 with the stage 141 and head 142 are mirror-finished and the substrates W1 and W2 are unlikely to peel off from the stage 141 and head 142.

[0018] Returning to Fig. 2, the stage driver 143 can move the stage 141 in the X and Y directions and rotate it around the Z axis. The head driver 144 has an elevation driver 1441 that raises and lowers the head 142 as indicated by the arrow AR1, an XY direction driver 1442 that moves the head 142 in the X and Y directions, and a rotation driver 1443 that rotates the head 142 in a rotation direction around the Z axis. The head driver 144 also has a piezo actuator 1444 that adjusts the inclination of the head 142 with respect to the stage 141, a pressure sensor 1445 that measures the pressure applied to the head 142, and a distance measurement unit 1446. The XY-direction driving unit 1442 and the rotation driving unit 1443 move the head 142 relative to the stage 141 in the X direction, the Y direction, and the rotation direction around the Z axis, thereby enabling alignment between the substrate W1 held on the stage 141 and the substrate W2 held on the head 142. Note that the stage driving unit 143 is not limited to a configuration in which it is disposed vertically below the stage 141, and may be configured, for example, such that a backup unit (not shown) that receives pressure is provided vertically below the stage 141, the stage driving unit 143 is disposed on the outer periphery of the stage 141, and drives the stage 141 from the side of the stage 141.

[0019] The lifting / lowering drive unit 1441 moves the head 142 vertically downward to bring the head 142 closer to the stage 141. The lifting / lowering drive unit 1441 also moves the head 142 vertically upward to move the head 142 away from the stage 141. When the lifting / lowering drive unit 1441 applies a driving force to the head 142 in a direction toward the stage 141 while the substrates W1 and W2 are in contact with each other, the substrate W2 is pressed against the substrate W1. The lifting / lowering drive unit 1441 is also provided with a pressure sensor 1441a that measures the driving force applied to the head 142 in a direction toward the stage 141. From the measured value of the pressure sensor 1441a, the pressure acting on the joint between the substrates W1 and W2 when the substrate W2 is pressed against the substrate W1 by the lifting / lowering drive unit 1441 can be detected. The pressure sensor 1441a has, for example, a piezoelectric element.

[0020] As shown in FIG. 4A, for example, a plurality of pairs of piezo actuators 1444 and pressure sensors 1445 (three pairs in FIG. 4A) are arranged between the head 142 and the XY direction drive unit 1442. The pressure sensor 1445 is interposed between the upper end of the piezo actuator 1444 and the lower side of the XY direction drive unit 1442. The piezo actuators 1444 can be individually expanded and contracted in the vertical direction, and by expanding and contracting, the tilt of the head 142 around the X axis and the Y axis and the vertical position of the head 142 are finely adjusted. In addition, the pressure sensor 1445 has, for example, a piezoelectric element and measures the pressure at a plurality of points on the lower surface of the head 142. Then, by driving each of the plurality of piezo actuators 1444 so that the pressures measured by the plurality of pressure sensors 1445 are equal, the substrates W1 and W2 can be brought into contact with each other while maintaining the lower surface of the head 142 and the upper surface of the stage 141 parallel to each other. The distance measurement unit 1446 is, for example, a laser distance meter, and measures the distance between the stage 141 and the head 142 without contacting the stage 141 and the head 142. The distance measurement unit 1446 measures the distance between the stage 141 and the head 142 from the difference between the reflected light on the upper surface of the stage 141 and the reflected light on the lower surface of the head 142 when a laser beam is irradiated from above the transparent head 142 toward the stage 141. As shown in FIG. 4A, the distance measurement unit 1446 measures the distance between three sites P11, P12, and P13 on the upper surface of the stage 141 and three sites P21, P22, and P23 on the lower surface of the head 142 that face the sites P11, P12, and P13 in the Z direction. Furthermore, if head 142 is tilted relative to stage 141, as shown by the dashed line in Figure 4B, the attitude of head 142 can be fine-tuned by extending one of the three piezoelectric actuators 1444 (see arrow AR3 in Figure 4B) to make the lower surface of head 142 and the upper surface of stage 141 approximately parallel to each other.

[0021] Returning to FIG. 2, the positional deviation measurement unit 150 measures the positional deviation between the substrate W1 and the substrate W2 in a direction perpendicular to the vertical direction (XY direction, rotation direction around the Z axis). The positional deviation measurement unit 150 has a first imaging unit 1501, a second imaging unit 1502, and mirrors 1504 and 1505. The first imaging unit 1501 and the second imaging unit 1502 are arranged on the opposite side of the stage 141 from the side that holds the substrate W1. The first imaging unit 1501 and the second imaging unit 1502 each have an imaging element (not shown) and a coaxial illumination system (not shown). As a light source for the coaxial illumination system, a light source that emits light (e.g., infrared light) that transmits through the substrates W1 and W2, the stage 141, and a window portion 121 provided in the chamber 120 is used.

[0022] For example, as shown in Figures 5A and 5B, two alignment marks (first alignment marks) MK1a and MK1b are provided on the substrate W1, and two alignment marks (second alignment marks) MK2a and MK2b are provided on the substrate W2. The first bonding apparatus 1 performs an alignment operation (alignment operation) of both substrates W1 and W2 while recognizing the positions of the alignment marks MK1a, MK1b, MK2a, and MK2b provided on both substrates W1 and W2 by the misalignment amount measurement unit 150. More specifically, the first bonding apparatus 1 first performs a rough alignment operation (rough alignment operation) of the substrates W1 and W2 while recognizing the alignment marks MK1a, MK1b, MK2a, and MK2b provided on the substrates W1 and W2 by the misalignment amount measurement unit 150, to make the two substrates W1 and W2 face each other. Thereafter, the first bonding apparatus 1 performs a more precise alignment operation (fine alignment operation) while simultaneously recognizing the alignment marks MK1a, MK2a, MK1b, and MK2b provided on the two substrates W1 and W2 using the position measurement unit 500.

[0023] Here, light emitted from a light source of a coaxial illumination system of the first imaging unit 1501 is reflected by a mirror 1504, travels in the +Z direction, and passes through a part or all of the window 121 and the substrates W1 and W2. The light that has passed through a part or all of the substrates W1 and W2 is reflected by the alignment marks MK1a and MK2a of the substrates W1 and W2, travels in the -Z direction, passes through the window 121, is reflected by the mirror 1504, and enters the imaging element of the first imaging unit 1501. Light emitted from a light source of a coaxial illumination system of the second imaging unit 1502 is reflected by a mirror 1505, travels in the +Z direction, and passes through a part or all of the window 121 and the substrates W1 and W2. The light transmitted through a part or the whole of the substrates W1 and W2 is reflected by the alignment marks MK1a and MK2a of the substrates W1 and W2, travels downward, transmits through the window portion 121, is reflected by the mirror 1505, and enters the imaging element of the second imaging unit 1502. In this manner, the positional deviation amount measuring unit 150 acquires a captured image GAa including the alignment marks MK1a and MK2a of the two substrates W1 and W2, and a captured image GAb including the alignment marks MK1b and MK2b of the two substrates W1 and W2, as shown in Fig. 6A and Fig. 6B. Note that the operation of capturing the captured image GAa by the first imaging unit 1501 and the operation of capturing the captured image GAb by the second imaging unit 1502 are performed substantially simultaneously.

[0024] The substrate heating units 1411 and 1421 are first bonded object heating units having electric heaters embedded in the back side of the holding mechanism when viewed from the surface side of the stage 141 and head 142 where the substrates W1 and W2 abut, for example, when the holding mechanism is an electrostatic chuck. The substrate heating units 1411 and 1421 heat the substrates W1 and W2 by transferring heat to the substrates W1 and W2 supported by the stage 141 and head 142. In addition, the temperature of the substrates W1 and W2 or the bonding portion thereof can be adjusted by adjusting the heat generation amount of the substrate heating units 1411 and 1421. The positional deviation amount measuring unit 150 measures the horizontal positional deviation amount of the substrate W1 with respect to the substrate W2 by recognizing the positions of alignment marks (alignment marks) provided on the substrates W1 and W2, respectively. The positional deviation amount measuring unit 150 recognizes the alignment marks of the substrates W1 and W2, for example, by using light (for example, infrared light) that passes through the substrates W1 and W2. The stage driving unit 143 performs an alignment operation between the substrates W1 and W2 by moving and rotating the stage 141 in the horizontal direction based on the amount of misalignment measured by the misalignment amount measuring unit 150. Both the measurement of the amount of misalignment by the misalignment amount measuring unit 150 and the alignment operation by the stage driving unit 143 are performed under the control of the control unit 9.

[0025] The second bonding apparatus 2A, 2B bonds the substrates W1, W2 temporarily bonded together in the first bonding apparatus 1. As shown in FIG. 7, the second bonding apparatus 2A, 2B includes a chamber 220, a stage 241, a head 242, a stage driving unit 243, a head driving unit 244, and substrate heating units 2411, 2421. In the following description, the ±Z direction in FIG. 8 is appropriately defined as the up-down direction, and the direction perpendicular to the Z direction is appropriately defined as the horizontal direction. The chamber 220 is connected to a vacuum pump 221a via an exhaust pipe 221b and an exhaust valve 221c. When the exhaust valve 221c is opened and the vacuum pump 221a is operated, the gas in the chamber 220 is exhausted to the outside of the chamber 220 through the exhaust pipe 221b, and the air pressure in the chamber 220 is reduced (depressurized). Moreover, the air pressure (degree of vacuum) within the chamber 220 can be adjusted by adjusting the amount of exhaust by varying the opening / closing amount of the exhaust valve 221c.

[0026] The stage 241 and the head 242 are disposed in the chamber 220 so as to face each other in the Z direction. The stage 241 supports a plurality of substrates W1 and W2 temporarily bonded to each other on its upper surface. The upper surface of the stage 241 and the lower surface of the head 242 are flat surfaces. The stage driving unit 243 can move the stage 141 in the XY directions and rotate it around the Z axis. The head driving unit 244 has an elevation driving unit 2441 that raises and lowers the head 242 as shown by the arrow AR3, an XY direction driving unit 1442 that moves the head 242 in the XY directions, and a rotation driving unit 2443 that rotates the head 242 in a rotation direction around the Z axis. The head driving unit 244 also has a piezo actuator 2444 for adjusting the inclination of the head 242 with respect to the stage 241, a pressure sensor 2445 for measuring the pressure applied to the head 242, and a distance measuring unit 2446. The head driving unit 244 moves the head 242 downward to bring the head 242 closer to the stage 141. The head driving unit 244 also moves the head 242 upward to move the head 242 away from the stage 241. When the head driving unit 244 applies a driving force to the head 242 in a direction toward the stage 241 while the head 242 is in contact with the plurality of substrates W1 and W2 temporarily bonded to each other, pressure is applied to the plurality of substrates W1 and W2 temporarily bonded to each other in a direction toward each other. The head driving unit 244 is also provided with a pressure sensor 2441a that measures the driving force applied by the head driving unit 244 to the head 242 in a direction toward the stage 241. The pressure sensor 2441a is, for example, a load cell, and the pressure applied to the plurality of substrates W1 and W2 temporarily bonded to each other by the head driving unit 244 can be detected from the measured value.

[0027] As in the first bonding device 1, a plurality of pairs of the piezo actuator 2444 and the pressure sensor 2445 are arranged between the head 242 and the XY direction drive unit 2442. The pressure sensor 1445 is interposed between the upper end of the piezo actuator 2444 and the lower side of the XY direction drive unit 2442, and each of them expands and contracts in the vertical direction, thereby finely adjusting the inclination of the head 242 around the X axis and the Y axis and the vertical position of the head 242. In addition, the pressure sensor 2445 measures the pressure at a plurality of points on the lower surface of the head 242, and by driving each of the plurality of piezo actuators 2444 so that the measured pressures are equal, the head 242 can be brought into contact with the plurality of substrates W1 and W2 that are temporarily bonded to each other while maintaining the lower surface of the head 242 and the upper surface of the stage 241 in parallel. As in the first bonding device 1, the distance measurement unit 2446 measures the distance between the stage 241 and the head 242. The substrate heating units 2411 and 2421 are composed of, for example, electric heaters. The substrate heating units 2411 and 2421 heat the substrates W1 and W2 by transferring heat to the substrates W1 and W2 supported by the stage 241 while the head 242 is in contact with the substrates W1 and W2. In addition, by adjusting the amount of heat generated by the substrate heating units 2411 and 2421, the temperature of the substrates W1 and W2 or their joints can be adjusted.

[0028] The control unit 9 is, for example, a personal computer, and has a CPU (Central Processing Unit) and a memory. The memory stores a program executed by the CPU. The control unit 9 controls the operations of the first bonding device 1, the second bonding device 2A, 2B, and the transport devices 82, 84 by outputting control signals thereto. The memory also stores preset positional deviation thresholds Δxth, Δyth, and Δθth for the relative calculated positional deviations Δx, Δy, and Δθ of the substrates W1 and W2, which will be described later. The control unit 9 converts measurement signals input from the pressure sensors 1441a, 1445 and the distance measurement unit 1446 of the first bonding device 1 into measurement information and acquires the same, and converts measurement signals input from the pressure sensors 2441a, 2445 and the distance measurement unit 2446 of the second bonding devices 2A, 2B into measurement information and acquires the same. Then, the control unit 9 controls the head driving unit 144 of the first bonding device 1 and the head driving units 244 of the second bonding devices 2A and 2B based on this measurement information.

[0029] The control unit 9 also converts the captured image signals input from the first imaging unit 1501 and the second imaging unit 1502 of the first bonding device 1 into captured image information and acquires it. Then, as shown in FIG. 6B, the control unit 9 calculates the positional deviation amounts Δxa, Δya between a pair of alignment marks MK1a, MK2a provided on the substrates W1, W2 based on the captured image GAa acquired from the first imaging unit 1501. Note that FIG. 6B shows a state in which the pair of alignment marks MK1a, MK2a are misaligned with each other. Similarly, the control unit 9 calculates the positional deviation amounts Δxb, Δyb between another pair of alignment marks MK1b, MK2b provided on the substrates W1, W2 based on the captured image GAb acquired from the second imaging unit 1502. Then, the control unit 9 calculates the relative positional deviations Δx, Δy, Δθ of the multiple substrates W1 and W2 in the X direction, Y direction, and rotation direction around the Z axis based on the positional deviations Δxa, Δya, Δxb, Δyb of these two sets of alignment marks and the geometric relationship between the two sets of marks. Then, the control unit 9 moves the head 142 in the X direction and Y direction and rotates it around the Z axis so that the calculated positional deviations Δx, Δy, Δθ are reduced. This reduces the relative positional deviations Δx, Δy, Δθ of the multiple substrates W1 and W2. In this way, the first bonding device 1 performs a fine alignment operation to correct the positional deviations Δx, Δy, Δθ of the two substrates W1 and W2 in the horizontal direction.

[0030] In the bonding system according to the present embodiment, for example, substrates W1 and W2 shown in Fig. 8A and Fig. 8B are bonded together. Here, the substrate W1 has one contour-shaped (circular frame-shaped) bonding portion BP13 formed along the periphery of the substrate W1 on the first main surface W1f side in the thickness direction, as shown in Fig. 8A and Fig. 8B, and a plurality of rectangular frame-shaped bonding portions BP11 formed inside the bonding portion BP13 on the first main surface W1f side. The substrate W2 has one contour-shaped (circular frame-shaped) bonding portion BP14 formed along the periphery of the substrate W2 on the second main surface W2f side in the thickness direction, and the same number of bonding portions BP12 as the bonding portion BP11 formed inside the bonding portion BP14 on the second main surface W2f side. Here, the bonding portions BP11 and BP13 are frame-shaped first bonding portions formed from metal, and the bonding portions BP12 and BP14 are second bonding portions formed from metal. The number of bonding portions BP112 formed inside the bonding portions BP14 on the second main surface W2f side of the substrate W2 may be different from the number of bonding portions BP11 formed on the substrate W1.

[0031] Alternatively, the substrates W1 and W2 may have a plurality of bonding portions BP31 and BP32 on the first and second main surfaces W1f and W2f in the thickness direction, respectively, as shown in Fig. 9. Here, the bonding portions BP31 and BP32 constitute bumps made of metal. The substrates W1 and W2 may have a single bonding portion BP41 and BP42 on the first and second main surfaces W1f and W2f in the thickness direction, respectively, as shown in Fig. 10, which is provided so as to cover substantially the entirety of the first and second main surfaces W1f and W2f.

[0032] The substrates W1 and W2 may be any of a Si substrate, a glass substrate, an oxide substrate (e.g., a silicon oxide (SiO2) substrate, an alumina substrate (Al2O3), sapphire, etc.), and a nitride substrate (e.g., silicon nitride (SiN), aluminum nitride (AlN)). At least one of the substrates W1 and W2 may have a metal portion and an insulating film exposed at the joint. Alternatively, at least one of the substrates W1 and W2 may have an insulating film formed by depositing an oxide or nitride exposed at the joint.

[0033] The bonding system according to the present embodiment performs a temporary bonding process in which the substrates W1 and W2 are temporarily bonded to each other after being subjected to a surface activation process, and a main bonding process in which the substrates W1 and W2 temporarily bonded to each other are heated to a main bonding temperature that is higher than the temporary bonding temperature at the time of temporary bonding and pressure is applied to the substrates W1 and W2 in a direction in which they approach each other, thereby main bonding the substrates W1 and W2 to each other. Here, when bonding the substrates W1 and W2 as shown in Fig. 8A and Fig. 8B, the first bonding device 1 brings the substrate W1 having the bonding parts BP11 and BP13 formed of metal and the substrate W2 having the bonding parts BP12 and BP14 formed of metal close to each other in a state in which the first main surface W1f side on which the bonding parts BP11 and BP13 are formed faces the second main surface W2f side on which the bonding parts BP12 and BP14 are formed, as shown by the arrow AR101 in Fig. 11A, for example. Then, as shown by arrow AR102 in Figure 11B, with joint BP1 of substrate W1 and joint BP2 of substrate W2 in contact with each other, the first bonding device 1 applies a driving force to the substrates W1 and W2 in a direction in which the substrates W1 and W2 approach each other, thereby temporarily bonding joints BP11, BP13 to joints BP12, BP14 to each other.

[0034] The first bonding device 1 may also temporarily bond three or more substrates. In this case, if the temperature at the start of bonding in the temporary bonding process is different from the temperature at the time of bonding, the substrate W1 slides against the stage 141 due to the difference in linear expansion coefficient between the stage 141 and the substrate W1 during heating. Therefore, when temporarily bonding the substrate W1 having a bonding portion formed of metal on both sides in the thickness direction and the substrate W2, if at least a part of the bonding portion comes into contact with the stage 141, there is a risk that scratches will be generated on at least a part of the surface of the bonding portion formed by the stage 141 due to the sliding of the substrate W1 against the stage 141. In particular, in the case of frame-shaped bonding portions BP11 and BP12 as shown in FIG. 8, scratches that straddle the surfaces of the bonding portions BP11 and BP12 that serve as sealing surfaces will cause leakage of the gas sealed inside the bonding portions BP11 and BP12, which is a problem. For this reason, in the temporary bonding process, after the substrates W1, W2, and W3 are held on the stage 141 and head 142, it is preferable to set the temperature of the stage 141 and head 142 to room temperature (25°C) or a low temperature that is higher than room temperature and not higher than about 100°C, and it is also preferable to maintain it constant.

[0035] 9, the first bonding apparatus 1 brings the substrate W1 having a plurality of bonding portions BP31 formed from a metal and the substrate W2 having the same number of bonding portions BP32 as the bonding portions BP31, close to each other with the first main surface W1f side on which the bonding portions BP31 are formed facing the second main surface W2f side on which the bonding portions BP32 are formed, as shown by the arrow AR301 in FIG. 12A. Then, the first bonding apparatus 1 applies a driving force to the substrates W1 and W2 in a direction in which the substrates W1 and W2 approach each other with the bonding portions BP31 of the substrate W1 and the bonding portions BP32 of the substrate W2 in contact with each other, as shown by the arrow AR302 in FIG. 12B, thereby temporarily bonding the bonding portions BP31 and BP32 to each other.

[0036] Here, when the bonding portions BP11 and BP12 of the substrates W1 and W2 are each formed of a metal, the arithmetic mean roughness (Ra) of their surfaces is several nm, and as shown in Fig. 13A, a gap SP1 is generated between the bonding portions BP11 and BP12 of the substrates W1 and W2 after the temporary bonding process. In the main bonding process, the second bonding apparatuses 2A and 2B heat the substrates W1 and W2 temporarily bonded to each other as described above to about 200°C and apply pressure to the substrates W1 and W2 in a direction to approach each other. As a result, as shown by the arrows in Fig. 13B, the metal atoms of the bonding portions BP11 and BP12 diffuse into the gap SP1 in a solid phase, so that the gap SP1 is filled with metal. More specifically, when pressure and heat are applied to the joints BP11 and BP12 in contact with each other as shown in Fig. 14A, metal atoms present in the contact area undergo solid-phase diffusion toward the gap between the joints BP11 and BP12 as shown by the arrows, and the contact area of ​​the joints BP11 and BP12 expands as shown in Fig. 14B. Then, the joints BP11 and BP12 are bonded together without any gaps as shown in Fig. 14C. This allows the space formed between the surfaces of the substrates W1 and W2 on which the joints BP11 and BP12 are formed and surrounded by the contours of the joints BP11 and BP12 to be sealed in the atmosphere in which the temporary bonding process and the main bonding process are performed.

[0037] Furthermore, in the main bonding process of substrates W1 and W2 shown in FIG. 10 described above, SAT images of substrates W1 and W2 bonded to each other were compared using an ultrasonic flaw detector when the temperatures of substrates W1 and W2 were set to 25°C (room temperature) and 200°C. In the main bonding process, the pressure applied to substrates W1 and W2 was 1 MPa, and the pressure was maintained for 10 minutes. As shown in FIG. 15A, when the temperature of substrates W1 and W2 was set to 25°C, a relatively large number of voids were observed between substrates W1 and W2. The bonding strength was also 0.1 J / m 2 The bonding strength was as low as 2.5 J / m or less, and sufficient bonding strength was not obtained. However, when the bonded substrates W1 and W2 were held, they did not peel off. On the other hand, when the temperature of the substrates W1 and W2 was set to 200° C., no voids were observed between the substrates W1 and W2, as shown in FIG. 15B. Also, the bonding strength was 2.5 J / m2 The results were high. This is believed to be because, by increasing the temperature of the substrates W1 and W2 to 200°C, solid-phase diffusion of metal atoms into the gap between the joints BP41 and BP42 occurs, and the gap between the joints BP41 and BP42 is filled with metal atoms. In this bonding process, even if the temperature of the substrates W1 and W2 is set to 200°C, sufficient bonding strength cannot be obtained when the pressure applied to the substrates W1 and W2 is reduced to 1 / 10. From this, it was found that by heating the substrates W1 and W2 to 200°C, metal atoms are easily diffused into the solid phase, and by applying pressure to the substrates W1 and W2, metal atoms move from the part between the joints BP41 and BP42 where they are in contact with each other and where pressure is applied to the gap between the joints 41 and 42 where pressure is not applied. For example, in the case of bonding Si substrates having mirror-like bonding surfaces with a calculated average surface roughness (Ra) of less than 0.5 nm, no voids were observed between the Si substrates when the temperature of the Si substrates was 25°C (room temperature) and the pressure applied to the Si substrates was 0.1 MPa, and when the temperature of the Si substrates was 200°C and the pressure applied to the Si substrates was 1 MPa, the bonding strength was 2.5 J / m 2 The strength was relatively high. From this, it was found that when the calculated average roughness (Ra) is less than 0.5 nm, heating and pressurization are not necessary, and strong bonding can be achieved without generating voids even if the temperature of the substrate is set to 25°C and the pressure applied is 0.1 MPa. Furthermore, this tendency is not limited to the surface bonding between the bonding portions BP41 and BP42 of the substrates W1 and W2 shown in Fig. 10, but similar results were obtained in the bonding between the bump-like bonding portions BP31 and BP32 shown in Fig. 9, or the bonding between the frame-shaped bonding portions BP11, BP12, BP13, and BP14 shown in Fig. 8.

[0038] Next, the flow of operations of the bonding system according to this embodiment from when a plurality of substrates W1, W2 are input into the bonding system to when the plurality of substrates W1, W2 are bonded together and removed from the bonding system will be described with reference to Fig. 16A to Fig. 24. The substrates W1, W2 are first placed at the introduction ports 811, 812 shown in Fig. 16A. When three substrates W1, W2, and W3 are to be bonded, the three substrates W1, W2, and W3 are placed at the introduction ports 811, 812, and 813, respectively.

[0039] When the substrate W1 is placed in the introduction port 811, the transport robot 821 takes out the substrate W1) from the introduction port 811, as shown by the arrow AR11 in FIG. 16A. Then, the transport robot 821 turns so that the tip of the arm faces the load lock unit 83, as shown by the arrow AR13. When the substrate W2 is placed in the introduction port 812, the transport robot 821 takes out the substrate W2 from the introduction port 812, and turns so that the tip of the arm faces the load lock unit 83. When the substrate W3 is placed in the introduction port 813, the transport robot 821 takes out the substrate W3 from the introduction port 813, and turns so that the tip of the arm faces the load lock unit 83.

[0040] Next, the gate 832 of the load lock unit 83 on the transfer device 82 side is opened, and the transfer robot 821 extends the arm to insert the tip of the arm into the chamber 831 of the load lock unit 83, as shown by the arrow AR18 in FIG. 16B. Then, the substrates W1 and W2 are transferred from the tip of the arm to the stage in the chamber 831 of the load lock unit 83. After that, when the transfer of the substrates W1 and W2 to the stage in the chamber 831 is completed, the transfer robot 821 retracts the arm, as shown by the arrow AR19 in FIG. 17A. Then, the gate 832 of the load lock unit 83 is closed. Then, the load lock unit 83 puts the inside of the chamber 831 into a reduced pressure state.

[0041] Next, after the gate 833 on the transfer device 84 side of the load lock unit 83 is opened, the transfer robot 841 extends the arm with the tip of the arm facing the load lock unit 83 side. Then, when the substrates W1 and W2 are transferred from the stage to the tip of the arm in the chamber 831 of the load lock unit 83, the transfer robot 841 contracts the arm as shown by the arrow AR20 to take out the substrates W1 and W2 from the chamber 831. Then, the gate 833 on the transfer device 84 side of the load lock unit 83 closes. Next, the transfer robot 841 turns so that the tip of the arm faces the first bonding device 1 side as shown by the arrow AR21 in FIG. 17B, and the first bonding device 1 opens the entrance for the substrates W1 and W2. Next, the transfer robot 841 extends the arm to insert the tip of the arm into the aforementioned chamber 120 (see FIG. 2) of the first bonding device 1. Then, as indicated by an arrow AR22, the substrates W1 and W2 are transferred from the tip of the arm of the transport robot 841 to the stage 141 or head 142 (see FIG. 2) of the first bonding apparatus 1. Thereafter, the transport robot 841 retracts the arm, and the first bonding apparatus 1 closes the transfer entrance for the substrates W1 and W2.

[0042] Here, as shown in FIG. 18, the first bonding apparatus holds the substrates W1 and W2 transferred from the transport robot 841 in the first bonding apparatus 1 on the stage 141 and the head 142 (see FIG. 2), respectively (step S1). Here, the first bonding apparatus 1 causes the stage 141 to hold only the peripheral portion of the substrate W1, and causes the head 142 to hold only the peripheral portion of the substrate W2 in a state in which the joint portions of the substrates W1 and W2 face each other. Specifically, for example, the control unit 9 drives an electrostatic chuck disposed on the stage 141 in a state in which the substrate W1 is placed on the stage 141, to hold the substrate W1 on the stage 141. In addition, the control unit 9 drives an electrostatic chuck disposed on the head 142 in a state in which the head 142 is brought into contact with the side of the substrate W2 arranged vertically below the head 142 opposite to the joint portion side by the transport robot 841 of the transport apparatus 84, to hold the substrate W2 on the head 142. Here, the first bonding apparatus 1 first causes the head 142 to hold the substrate W2 to be held thereon. Here, the substrate W2 is aligned based on images captured by the first imaging unit 1501 and the second imaging unit 1502 of the positional deviation measuring unit 150 from vertically below the substrate W2 while the peripheral portion of the substrate W2 is held by, for example, lift pins (not shown) provided on the stage 141, and then the substrate W2 is held by the head 142. Also, by first causing the head 142 to hold the substrate W2, it is possible to prevent dust from falling onto the substrate W1.

[0043] Next, the first bonding device 1 performs an activation process to activate the bonded portion of the substrates W1 and W2 (step S2). In this activation process, the first bonding device 1 moves the particle beam sources 161 and 162 as shown by the arrows AR23 while irradiating the bonded portion of the substrates W1 and W2 with a particle beam, as shown in Fig. 19A and Fig. 19B. Here, since the particle beam sources 161 and 162 have variations in intensity in the moving direction within the projection plane of the particle beam alone, in order to reliably irradiate the entire substrates W1 and W2 with the particle beam, the particle beam is irradiated up to an area including the covers 122A and 122B on the outer side of both ends of the substrate W1 in the moving direction of the particle beam sources 161 and 162. Here, the first bonding device 1 irradiates the bonded portion of the substrates W1 and W2 with a particle beam while moving the particle beam sources 161 and 162 in the +Y direction as shown by the arrow AR23, and then irradiates the bonded portion of the substrates W1 and W2 with a particle beam while moving the particle beam sources 161 and 162 in the -Y direction. The moving speed of the particle beam sources 161 and 162 is set to, for example, 1.2 to 14.0 mm / sec. The power supplied to the particle beam sources 161 and 162 is set to, for example, 1 kV and 100 mA. The flow rate of the argon gas introduced into the discharge chamber 1601 of each of the particle beam sources 161 and 162 is set to, for example, 50 sccm.

[0044] Returning to FIG. 18, the first bonding apparatus 1 then performs a temporary bonding process for temporarily bonding the substrates W1 and W2 together (step S3). Here, the temporary bonding process performed by the first bonding apparatus 1 will be described in detail with reference to FIG. 20. In FIG. 20, the first bonding apparatus 1 completes the measurement of the distance between the upper surface of the stage 141 and the lower surface of the head 142 by the distance measurement unit 1446 in a state in which the substrates W1 and W2 are not held by the stage 141 and the head 142, and stores the result in the memory of the control unit 9. Furthermore, it is assumed that the measurement result of the thickness of the substrates W1 and W2 has already been stored in the memory. First, the first bonding apparatus 1 calculates the distance between the bonding portion of the substrate W1 and the bonding portion of the substrate W2 based on the distance between the upper surface of the stage 141 and the lower surface of the head 142 in a state in which the substrates W1 and W2 are not held by the stage 141 and the head 142, and the thickness of the substrates W1 and W2. Then, the first bonding apparatus 1 moves the head 142 vertically downward based on the calculated distance to bring the substrates W1 and W2 closer to each other (step S101). Next, the first bonding apparatus 1 calculates the amount of misalignment of the substrate W1 with respect to the substrate W2 while the substrates W1 and W2 are spaced apart from each other (step S102). Here, the control unit 9 first acquires the captured images GAa and GAb (see FIG. 6A) of the two substrates W1 and W2 in a non-contact state from the first imaging unit 1501 and the second imaging unit 1502 of the misalignment amount measuring unit 150. Then, the control unit 9 calculates the amounts of misalignment Δx, Δy, and Δθ of the two substrates W1 and W2 in the X direction, the Y direction, and the rotational direction around the Z axis based on the two captured images GAa and GAb. Specifically, the control unit 9 calculates the misalignment amounts Δxa and Δya (see FIG. 6B) using a vector correlation method based on a captured image GAa obtained by simultaneously reading alignment marks MK1a and MK2a spaced apart in the Z direction. Similarly, the control unit 9 calculates the misalignment amounts Δxb and Δyb using a vector correlation method based on a captured image GAb obtained by simultaneously reading alignment marks MK1b and MK2b spaced apart in the Z direction. Then, the control unit 9 calculates the misalignment amounts Δx, Δy, and Δθ in the horizontal direction of the two substrates W1 and W2 based on the misalignment amounts Δxa, Δya, Δxb, and Δyb.

[0045] Returning to FIG. 20, thereafter, the first bonding apparatus 1 performs alignment by moving the substrate W2 relative to the substrate W1 so as to correct the calculated misalignment amounts Δx, Δy, and Δθ (step S103). Here, the first bonding apparatus 1 moves the head 142 in the X direction, the Y direction, and the rotation direction around the Z axis so as to eliminate the misalignment amounts Δx, Δy, and Δθ while fixing the stage 141. Next, the first bonding apparatus 1 brings the substrates W1 and W2 into contact with each other (step S104). Next, the first bonding apparatus 1 measures the misalignment amount of the substrate W2 relative to the substrate W1 while the bonding portion of the substrate W1 is in contact with the bonding portion of the substrate W2 (step S105). At this time, the first bonding apparatus 1 measures the misalignment amount of the substrates W1 and W2 while the contact portions of the substrates W1 and W2 are bonded by intermolecular forces and the movement of the substrate W2 relative to the substrate W1 is restricted. Thereafter, the first joining apparatus 1 determines whether or not all of the calculated positional deviation amounts Δx, Δy, and Δθ are equal to or smaller than preset positional deviation amount threshold values ​​Δxth, Δyth, and Δθth (step S106).

[0046] Here, it is assumed that the first bonding apparatus 1 determines that any one of the calculated positional deviation amounts Δx, Δy, and Δθ is greater than the preset positional deviation amount thresholds Δxth, Δyth, and Δθth (step S106: No). In this case, the first bonding apparatus 1 separates the substrate W2 from the substrate W1 (step S107). At this time, the first bonding apparatus 1 controls the lift of the head 142 so that the tensile pressure of the substrate W2 when peeling the substrate W2 from the substrate W1 is constant. As a result, the substrate W2 is separated from the substrate W1, and the contact state between the substrates W1 and W2 is released.

[0047] Next, the first bonding apparatus 1 calculates the correction movement amount of the substrates W1 and W2 to make all the calculated positional deviation amounts Δx, Δy, and Δθ equal to or less than the positional deviation amount thresholds Δxth, Δyth, and Δθth (step S108). Here, the control unit 9 calculates the correction movement amount to move the substrates W1 and W2 by the movement amount corresponding to the difference between the positional deviation amounts Δx, Δy, and Δθ between the substrates W1 and W2 when the substrate W2 is in contact with the substrate W1, and the positional deviation amount between the substrates W1 and W2 when the substrate W2 is not in contact with the substrate W1. By offsetting the substrates W1 and W2 by the correction movement amount and performing alignment, if a similar positional deviation occurs due to contact between the substrates W1 and W2 when the substrates W1 and W2 come into contact with each other again, the positional deviation of the substrates W1 and W2 will be eliminated. Next, the first bonding apparatus 1 performs alignment so as to correct the relative positional deviations Δx, Δy, and Δθ between the two substrates W1 and W2 while the two substrates W1 and W2 are not in contact with each other (step S109). Here, the first bonding apparatus 1 moves the head 142 in the X direction, the Y direction, and the rotation direction around the Z axis by the correction movement amount calculated in step S108 while the stage 141 is fixed. In this way, the first bonding apparatus 1 adjusts the relative position of the substrate W2 with respect to the substrate W1 so as to reduce the positional deviations Δx, Δy, and Δθ while the substrates W1 and W2 are separated from each other. Then, the first bonding apparatus 1 performs the process of step S104 again.

[0048] On the other hand, it is assumed that the first bonding apparatus 1 judges that all of the calculated positional deviations Δx, Δy, and Δθ are equal to or less than the preset positional deviation thresholds Δxth, Δyth, and Δθth (step S106: Yes). In this case, the first bonding apparatus 1 temporarily bonds the substrates W1 and W2 together by pressing the substrate W1 against the substrate W2 while maintaining the substrates W1 and W2 at a temporary bonding temperature, which is a temperature at which the substrates W1 and W2 are temporarily bonded together, while the substrates W1 and W2 are in contact with each other (step S110). Here, the temporary bonding temperature is a temperature of 150° C. or less, and preferably a temperature of 60° C. or less. After that, the first bonding apparatus 1 releases the substrate W2 from the head 142 (step S111).

[0049] Returning to Fig. 18, the first bonding apparatus 1 next determines whether or not there is a substrate W3 to be bonded to the temporarily bonded substrates W1 and W2 other than the substrates W1 and W2 (step S4). If the first bonding apparatus 1 determines that there is a substrate W1 to be bonded to the temporarily bonded substrates W1 and W2 (step S4: Yes), it causes the head 142 (see Fig. 2) to hold the substrates W3 (step S1) while holding the temporarily bonded substrates W1 and W2 on the stage 141 (see Fig. 2). Then, the first bonding apparatus 1 again performs the activation process (step S2) and the temporary bonding process (step S3) as described above.

[0050] Returning to FIG. 18, on the other hand, when the first bonding apparatus 1 determines that there are no other substrates to be temporarily bonded (step S4: No), it releases the holding of the temporarily bonded substrates W1 and W2 (W1, W2, W3) (step S5). Then, the transfer robot 841 receives the temporarily bonded substrates W1 and W2 (W1, W2, W3) from the first bonding apparatus 1 and transfers them to the second bonding apparatuses 2A and 2B (step S6). Here, the transfer robot 841 extends the arm and inserts the tip of the arm into the chamber 120 (see FIG. 2) of the first bonding apparatus 1, and the substrates W1 and W2 are transferred from the stage 141 to the tip of the arm. Then, the transfer robot 841 retracts the arm to take out the substrates W1 and W2 from the activation processing apparatus 2, as shown by the arrow AR24 in FIG. 21A. Next, the transport robot 841 turns so that the tip of the arm faces the second bonding apparatus 2A side, as shown by the arrow AR25 in FIG. 21B. Then, when the second bonding apparatus 2A opens the entrance for the substrates W1 and W2, the transport robot 841 extends the arm and inserts the tip of the arm into the chamber 220 (see FIG. 7) of the second bonding apparatus 2A. Then, as shown by the arrow AR26 in FIG. 21B, the substrates W1 and W2 temporarily bonded to each other are transferred from the tip of the arm of the transport robot 841 to the stage 241 (see FIG. 7) of the second bonding apparatus 2A. Also, when the second bonding apparatus 2A is performing the above-mentioned main bonding process, the transport robot 841 turns so that the tip of the arm faces the second bonding apparatus 2B side, as shown by the arrow AR27 in FIG. 22. Next, when the second bonding apparatus 2B opens the entrance for the substrates W1 and W2, the transport robot 841 extends its arm and inserts the tip of the arm into the chamber 220 (see FIG. 7) of the second bonding apparatus 2B. Then, as shown by the arrow AR28 in FIG. 22, the substrates W1 and W2 temporarily bonded to each other are transferred from the tip of the arm of the transport robot 841 to the stage 241 (see FIG. 7) of the second bonding apparatus 2B.

[0051] Returning to FIG. 19, thereafter, the second bonding apparatus 2 performs a main bonding process in which the temporarily bonded substrates W1 and W2 (W1, W2, W3) are bonded together by applying pressure and heating (step S7). Here, the main bonding process performed by the second bonding apparatuses 2A and 2B according to this embodiment will be described in detail with reference to FIG. 23. In addition, in FIG. 23, the second bonding apparatuses 2A and 2B complete the measurement of the distance between the upper surface of the stage 241 and the lower surface of the head 242 by the distance measurement unit 2446 in a state in which the substrates W1, W2, and W3 are not held on the stage 241, and store the result in the memory of the control unit 9. Furthermore, it is assumed that the measurement result of the thicknesses of the substrates W1, W2, and W3 has already been stored in the memory. First, the second bonding apparatuses 2A and 2B make the stage 241 hold the temporarily bonded substrates W1 and W2 (step S201).

[0052] Next, the second bonding apparatus 2A, 2B calculates the distance between the head 242 and the temporarily bonded substrates W1, W2 (W1, W2, W3) based on the distance between the upper surface of the stage 241 and the lower surface of the head 242 when the substrates W1, W2 (W1, W2, W3) are not held by the stage 241 and the thicknesses of the substrates W1, W2 (W1, W2, W3). Then, the second bonding apparatus 2A, 2B moves the head 242 vertically downward based on the calculated distance to bring the head 242 into contact with the substrates W1, W2 (step S202). Next, the second bonding apparatus 2A, 2B applies a driving force to the substrates W1, W2 (W1, W2, W3) in a direction in which the substrates W1, W2 (W1, W2, W3) approach each other while maintaining the temperatures of the substrates W1, W2 at the above-mentioned main bonding temperature, thereby pressurizing the temporarily bonded substrates W1, W2 (W1, W2, W3) (step S203). After that, the second bonding apparatus 2A, 2B raises the temperature of the temporarily bonded substrates W1, W2 (W1, W2, W3) while maintaining the substrates W1, W2 (W1, W2, W3) in a pressurized state (step S204). Here, the second bonding apparatus 2A, 2B maintains the temperature of the substrates W1, W2 (W1, W2, W3) raised to the main bonding temperature, which is a preset temperature during main bonding, for a preset time. For example, the substrates W1 and W2 (W1, W2, W3) are heated to 200° C. and maintained under a pressure of 10 MPa for 10 minutes. The actual bonding temperature is set so that the temperature difference from the temporary bonding temperature is 200° C. or less, and is preferably 250° C. or less. The actual bonding temperature is 150° C. or more, preferably 200° C. or more, and more preferably 250° C. or more.

[0053] Next, the second bonding apparatus 2A, 2B raises the head 242 to separate it from the bonded substrates W1, W2 (step S205). Then, the second bonding apparatus 2A, 2B stops the electrostatic chuck of the stage 241 to release the bonded substrates W1, W2 (W1, W2, W3) (step S206), thereby completing this bonding process. Then, the second bonding apparatus 2A, 2B opens the loading / unloading entrance for the substrates W1, W2 (W1, W2, W3).

[0054] Here, after the activation treatment step (S2), until the main bonding step (S7) is performed, in order to maintain the bonded portion of the substrates W1 and W2 in an activated state, a 10 -3 After the activation treatment step (S2), the vacuum level is maintained at 10 Pa or higher until the main bonding step (S7) is performed. -6 A vacuum degree higher than 10 Pa is preferable. Thus, until the main bonding step (S7) is completed, -3 Since it is necessary to maintain a vacuum of more than 10 Pa, the inside of the transfer device 84 where the bonding portions of the substrates W1 and W2 are exposed and the inside of the chamber 220 of the second bonding device 2A and 2B are also kept at a vacuum of more than 10 Pa. -3 It is necessary to maintain a vacuum degree higher than 1000 Pa. However, when the bonding portion of the substrates W1 and W2 is made of Au or Cu, the vacuum degree may be maintained at a degree higher than 1000 Pa after the activation treatment step (S2) until the main bonding step (S7) is performed. In this case, it is preferable to maintain a vacuum degree higher than 0.1 Pa. When the substrates W1 and W2 are transported in a state in which the bonding portion BP13 formed along the periphery of the substrate W1 and the bonding portion BP14 formed along the periphery of the substrate W2 are bonded to seal the inside, the pressure inside the transport device 84 and in the chamber 220 of the second bonding device 2A and 2B is not particularly limited and may be, for example, atmospheric pressure.

[0055] After the temporary bonding step (S3), and before the main bonding step (S7), the temperatures of the substrates W1, W2 are preferably set to a temperature within a preset temperature range including the temporary bonding temperature, for example, within a temperature range of ±30% of the temporary bonding temperature.

[0056] Thereafter, the transport robot 841 extends the arm and inserts the tip of the arm into the chamber 220 (see FIG. 7) of the second bonding apparatus 2A. Then, the bonded substrates W1 and W2 are transferred from the stage 241 of the second bonding apparatus 2A to the tip of the arm of the transport robot 841. Next, the transport robot 841 retracts the arm to take out the bonded substrates W1 and W2 from the second bonding apparatus 2A as shown by the arrow AR29 in FIG. 24A. Then, the second bonding apparatus 2A closes the entrance and exit for the substrates W1 and W2 again. Next, the transport robot 841 turns so that the tip of the arm faces the load lock unit 83 as shown by the arrow AR30. Then, when the gate 833 on the transfer device 84 side of the load lock unit 83 is opened, the transport robot 841 extends the arm with the tip of the arm facing the load lock unit 83. Then, when the bonded substrates W1 and W2 are transferred from the tip of the arm to the stage in the chamber 831 of the load lock unit 83, the transfer robot 841 retracts the arm as indicated by the arrow AR31 in Fig. 24B. Then, the gate 833 on the transfer device 84 side of the load lock unit 83 is closed.

[0057] Next, after the gate 832 on the transfer device 82 side of the load lock unit 83 is opened, the transfer robot 821 extends the arm with the tip of the arm facing the load lock unit 83 side, and inserts the tip of the arm into the chamber 831 of the load lock unit 83. Then, the bonded substrates W1 and W2 are transferred from the stage in the load lock unit 83 to the tip of the arm of the transfer robot 821. Next, the transfer robot 821 contracts the arm as shown by the arrow AR32 to take out the bonded substrates W1 and W2 from the load lock unit 83, and then the gate 832 on the transfer device 82 side of the load lock unit 83 is closed. Next, the transfer robot 821 turns so that the tip of the arm faces the opposite side to the load lock unit 83 side. Then, the transfer robot 821 faces the tip of the arm toward the take-out port 814 while holding the bonded substrates W1 and W2. Next, the transfer robot 821 extends the arm and inserts the tip of the arm into the take-out port 814 to place the joined substrates W1 and W2 in the take-out port 814.

[0058] In the bonding system according to the present embodiment, as shown in FIG. 25, the transport device 84 transports the substrates W1 and W2 from the load lock section 83 to the first bonding apparatus 1, and after the activation process and the temporary bonding process are performed in the first bonding apparatus 1, the transport device 84 transports the temporarily bonded substrates W1 and W2 to, for example, the second bonding apparatus 2A. Next, at the same time that the main bonding process is started in the second bonding apparatus 2A, the transport device 84 transports the other substrates W1' and W2' to be bonded to, for example, the load lock section 83 to the first bonding apparatus 1. After that, after the activation process and the temporary bonding process are performed in the first bonding apparatus 1, the transport device 84 transports the temporarily bonded substrates W1 and W2 to the second bonding apparatus 2B, which has not yet undergone the main bonding process. This allows the number of processes per unit time to be improved, as compared to a case in which, for example, the bonding system includes only one second bonding apparatus 2A and is configured to repeatedly perform the activation process, the temporary bonding process, and the main bonding process. For example, when bonding the substrates W1 and W2 and bonding the substrates W1' and W2', in the case of a bonding system having only one second bonding apparatus 2A described above, the processing time is (dT1+dT2+dT3+dT4)×2. Here, dT1 is the time required for the substrates W1 and W2 to be transported from the load lock unit 83 to the first bonding apparatus 1, and dT2 is the time required for the activation process and the temporary bonding process. In addition, dT3 is the time required for the substrates W1 and W2 temporarily bonded to each other to be transported from the first bonding apparatus 1 to the second bonding apparatus 2A and 2B, and dT4 is the time required for the main bonding process. On the other hand, in the bonding system according to the present embodiment, the processing time is (dT1+dT2+dT3)×2+dT4. In other words, the processing time is shortened by the time dT4 required for the main bonding process. In addition, dT2 is, for example, 1 min, and dT4 is, for example, 10 min.

[0059] By the way, the amount of distortion occurring in the substrates W1 and W2 varies depending on the temperature at the start of bonding in the above-mentioned temporary bonding process. For example, if the temperature of the substrates W1 and W2 in the temporary bonding process is 100°C or higher, the amount of distortion of the substrates W1 and W2 is about 1 μm. In contrast, if the temperature of the substrates W1 and W2 in the temporary bonding process is about 25°C, the amount of distortion of the substrates W1 and W2 is reduced to 0.2 μm or less. At 60°C, it is 0.5 μm or less. Furthermore, when the temperature is raised to 200°C, a deviation of about 2 μm occurs. For this reason, it is preferable that the temperature of the substrates W1 and W2 in the temporary bonding process is 60°C or lower, about room temperature. Note that even if the substrates W1 and W2 temporarily bonded to each other are heated to 200°C or higher, the amount of distortion of the substrates W1 and W2 hardly changes. This indicates that they are already partially bonded in the temporary bonding state, and subsequent heating will not cause deviation. Therefore, if the temporary bonding process is performed at room temperature or below 60°C, then even if the temperature of the temporarily bonded substrates W1 and W2 is subsequently raised to 200°C or higher in the aforementioned main bonding process, the amount of distortion of the substrates W1 and W2 will not increase.

[0060] As described above, in the bonding system according to the present embodiment, after the activation process is performed on the multiple substrates W1 and W2, the multiple substrates W1 and W2 are temporarily bonded together by contacting their bonding portions with each other under reduced pressure. Thereafter, under reduced pressure, the multiple substrates W1 and W2 temporarily bonded together are permanently bonded together by applying pressure to the multiple substrates W1 and W2 in a direction toward each other while maintaining the temperature of the multiple substrates W1 and W2 at a permanent bonding temperature that is higher than the temporary bonding temperature at the time of temporary bonding. This allows the multiple substrates W1 and W2 to be temporarily bonded together at a relatively low temperature at which the positional accuracy of the objects to be bonded together due to the influence of thermal distortion is maintained, and then the temperature of the multiple substrates W1 and W2 can be increased and pressurized and heated. Therefore, the two objects to be bonded together can be firmly bonded together while suppressing the positional deviation between the multiple substrates W1 and W2.

[0061] In addition, the second bonding apparatus 2A, 2B according to the present embodiment applies pressure to the temporarily bonded substrates W1, W2 (W1, W2, W3) in a direction in which they approach each other, and heats the substrates W1, W2 (W1, W2, W3) to the above-mentioned main bonding temperature, thereby bonding the bonding portions BP11, BP12, BP21, BP22, BP23, BP24 of the substrates W1, W2 (W1, W2, W3) in a solid state. As a result, pressure is applied in a state in which the metal atoms forming the bonding portions are easily moved by being heated to the main bonding temperature, so that the metal atoms diffuse into the gaps between the bonding portions BP11, BP12, BP21, BP22, BP23, BP24 in a solid state, and the bonding portions BP11, BP12, BP21, BP22, BP23, BP24 are bonded together without any gaps. Therefore, this is effective when, for example, substrates W1 and W2 having frame-shaped bonding portions BP21, BP22, BP23, and BP24 are bonded together to seal the insides of the bonding portions BP21, BP22, BP23, and BP24, which is called sealed bonding.

[0062] Conventionally, when performing so-called sealing bonding on a Si substrate, a glass substrate, or the like, the surface of the Si substrate, the glass substrate, or the like must be finished to a mirror state with a calculated average roughness (Ra) of about 0.3 nm, so that it is difficult to fabricate a structure in which a device formed on a substrate that is a so-called intermediate layer is sealed. In contrast, in the bonding system according to the present embodiment, by forming the bonding portion that is the so-called sealing layer from a metal, it is possible to fill and seal the minute gaps formed between the bonding portions that are bonded to each other by utilizing solid-phase diffusion of metal atoms by heating and pressurizing, even if the Ra of the bonding portion is 0.5 nm or more. With the bonding method according to the present embodiment, even if a device is formed on a substrate that is a so-called intermediate layer, it can be sealed later with a bonding portion formed from a metal, so that a structure that seals such a device can be easily fabricated. In addition, by forming the bonding portion from Au, the hardness of the bonding portion is relatively low, so that it is easy to crush and is difficult to oxidize, and an activated surface is maintained. For this reason, Au is suitable as a material for forming the bonding portion. In addition, as a metal, Cu is also the second easiest to handle after Au. It is soft and difficult to oxidize for a metal.

[0063] Furthermore, the stage 141 of the first bonding device 1 according to this embodiment holds the substrate W1 in a state in which the bonding portion of the substrate W1 faces the bonding portion of the substrate W2 and is in contact with only the periphery of the substrate W1. This makes it possible to prevent foreign matter from adhering to or scratching the surface to which the substrate W3 is to be bonded, for example, when the substrate W3 is to be bonded to the surface of the substrate W1 opposite to the surface to which the substrate W2 is to be bonded. This makes it possible to prevent bonding defects from occurring when the substrate W3 is bonded to the substrate W1.

[0064] Incidentally, in the main bonding process, when the thickness of the substrates W1, W2, and W3 is thin and the difference between the expansion coefficient of the stage 241 and the head 242 is large, if the temperature difference before and after the temperature rise is large, there is a risk that the substrates W1, W2, and W3 may break, crack, or the like. For this reason, it is preferable that the temperature difference before and after the temperature rise in the main bonding process is within 150°C. For example, the temporary bonding temperature in the temporary bonding process may be set to 150°C, and the main bonding temperature in the main bonding process may be set to 250°C. In this case, even if the temperature of the substrates W1, W2, and W3 is set to 50°C when the substrates W1, W2, and W3 are transported, the temperature difference before and after the temperature rise in the main bonding process can be within 150°C. In addition, by maintaining the temperature of the stage 141 of the first bonding device 1 at 150°C and the temperature of the stage 241 of the second bonding devices 2A and 2B at 250°C, the processing time can be shortened by the time required to heat and cool the stages 141 and 241, thereby improving the mass productivity of the bonding system. Also, the temporary bonding temperature may be 100° C. and the main bonding temperature may be 200° C., or the temporary bonding temperature may be so-called room temperature, which is 50° C. or less, and the main bonding temperature may be 150° C. In particular, by setting the temporary bonding temperature to room temperature or a low temperature, it is possible to avoid the occurrence of scratches on the substrates W1, W2, and W3 in the temporary bonding process and improve precision without thermal strain, which is preferable.

[0065] Furthermore, the transport device 84 according to the present embodiment transports the substrates W1, W2 (W1, W2, W3) temporarily bonded to each other from the first bonding device 1 to the second bonding device 2A, 2B under reduced pressure. As a result, for example, when the substrates W1, W2 (W1, W2, W3) have frame-shaped bonding parts BP21, BP22, BP23, BP24, even if the insides of the bonded bonding parts BP cannot be completely sealed, the insides of the bonding parts BP21, BP22, BP23, BP24 can be maintained in a reduced pressure state and the surfaces of the bonding parts BP21, BP22, BP23, BP24 can be maintained in an activated state and transported to the second bonding device 2A, 2B. Therefore, in the second bonding device 2A, 2B, the substrates W1, W2 (W1, W2, W3) can be bonded in a state in which the insides of the bonding parts BP21, BP22, BP23, BP24 are sealed in a reduced pressure state.

[0066] Moreover, the first bonding apparatus 1 according to this embodiment performs the temporary bonding process immediately after the activation process in the same chamber 120. Therefore, by performing bonding immediately after the activation process in a chamber that maintains a vacuum level that suppresses the floating of other molecules, it is possible to suppress adhesion of other molecules to the active surfaces of the bonding parts BP11, BP12, BP21, BP22, BP23, and BP24 of the substrates W1 and W2 (W1, W2, W3), and therefore the bonding parts BP11, BP12, BP21, BP22, BP23, and BP24 of the substrates W1 and W2 (W1, W2, W3) can be temporarily bonded well to each other.

[0067] Furthermore, the bonding system according to this embodiment includes a plurality of second bonding devices 2 A, 2 B. This makes it possible to increase the number of processes per unit time, as described above.

[0068] Although the embodiment of the present invention has been described above, the present invention is not limited to the configuration of the above-mentioned embodiment. For example, the bonding system may include an activation treatment device that activates the bonding parts BP11, BP12, BP21, BP22, BP23, BP24 of the substrates W1, W2 (W1, W2, W3) by exposing the bonding parts BP11, BP12, BP21, BP22, BP23, BP24 of the substrates W1, W2 (W1, W2, W3) to plasma. In this case, the activation treatment device may be connected to a transport device 84, and the transport device 84 may transport the substrates W1, W2 (W1, W2, W3) whose bonding parts have been activated in the activation treatment device under reduced pressure to a first bonding device that temporarily bonds the substrates W1, W2 (W1, W2, W3) to each other.

[0069] In the embodiment, an example has been described in which a three-layer structure is produced by bonding the substrates W1, W2, and W3 to each other, but the number of substrates to be bonded to each other is not limited to 3. For example, a four or more layer structure may be produced by temporarily bonding four or more substrates to each other and then permanently bonding them.

[0070] In the embodiment, an example in which the bonding portion is a metal has been described, but the material of the bonding portion is not limited to metal. Materials other than metals may be used as long as they can be bonded by activating the surface. For example, Si, sapphire, Lt, LN, SIC, etc. may be used.

[0071] In the embodiment, an example in which the stage 141 has a flat shape and holds the entire substrate W1 has been described, but the present invention is not limited to this. In the temporary bonding process of the multiple substrates W1, W2, and W3 of the embodiment, the stage 141 may hold the periphery of the substrate W1 to raise the center of the substrate W1 from the substrate jig. In this case, a recess 141c may be provided on the inside of the stage 141. The depth of the recess 141c is set to a depth such that the bottom of the recess 141c does not contact the substrates W1 and W2 when the substrates W1 and W2 are held, and is set to, for example, 1 μm or more. This makes it possible to prevent the portion P2 of the substrate W1 where the bonding portion BP22 is formed from contacting the stage 141.

[0072] In addition, in the temporary bonding process of the multiple substrates W1, W2, and W3 of the embodiment, the peripheral portion of the substrate W1 may be held by the stage 141 or a substrate jig placed on the stage 141 to float the center portion of the substrate W1 from the substrate jig. In this case, the first bonding device 1 temporarily bonds the peripheral portions of the substrate W1, which is the first bonded object having bonding portions BP21, BP22, BP25, and BP26 formed of metal on both sides in the thickness direction as shown in FIG. 26A, and the substrate W2, which is the second bonded object having at least bonding portions BP23 and BP27 formed of metal, in the temporary bonding process. Here, the substrate W1 is held on the stage 141 together with the substrate jig 835 in a state in which the substrate W1 is placed on the substrate jig 835 having a recess 835a on the inside. Although not shown, the substrate jig 835 has an outer periphery step so that the substrate W1 does not shift when the substrate W1 is transported. The first bonding apparatus 1 further bonds the substrates W1 and W2, which are temporarily bonded to each other, to a substrate W3, which is a third bonded object having bonding parts BP24 and BP28 made of metal, temporarily or completely to each other on the entire surfaces of the substrates W1, W2, and W3. Here, the bonding part BP25 is a first bonding part that is contour-shaped (circular frame-shaped) and is formed along the periphery of the substrate W1 on one main surface side in the thickness direction of the substrate W1, the bonding part BP21 is a rectangular frame-shaped first bonding part formed in a plurality of parts inside the bonding part BP25 on one main surface side in the thickness direction of the substrate W1. The bonding part BP26 is a third bonding part that is contour-shaped (circular frame-shaped) and is formed along the periphery of the substrate W1 on the other main surface side in the thickness direction of the substrate W1, and the bonding part BP22 is a rectangular frame-shaped third bonding part formed in a plurality of parts inside the bonding part BP26 on the other main surface side in the thickness direction of the substrate W1. In addition, joint BP27 is contour-shaped (circular frame-shaped) and is a second joint formed along the periphery of substrate W2 on one main surface side in the thickness direction of substrate W2, and joint BP23 is rectangular frame-shaped and is a second joint formed in multiple numbers inside joint BP27 on the main surface side facing substrate W1 in the thickness direction of substrate W2.Furthermore, the bonding portion BP28 is contour-shaped (circular frame-shaped) and is a fourth bonding portion formed along the periphery of the substrate W3 on one main surface side in the thickness direction of the substrate W3, and the bonding portion BP24 is rectangular frame-shaped and is a fourth bonding portion formed in a plurality of parts inside the bonding portion BP28 on the main surface side facing the substrate W1 in the thickness direction of the substrate W3. When the first bonding device 1 temporarily bonds the substrates W1 and W2 together with the bonding portions BP21, BP23, BP25, and BP27 in contact with each other, when applying a driving force to the substrates W1 and W2 in a direction in which the substrates W1 and W2 approach each other as shown by the arrow AR103, only the peripheral portions P1 of the substrates W1 and W2 are pressurized, and the bonding portions BP25 and BP27 are temporarily bonded together. When the first bonding device 1 temporarily bonds the substrate W3, which has the bonding parts BP24 and BP28 formed on the substrate W1 side of the two substrates W1 and W2 temporarily bonded to each other as shown in FIG. 26B, a driving force is applied to the substrates W1 and W2 in a direction in which the temporarily bonded substrates W1 and W2 and the substrate W3 approach each other as shown by the arrow AR104. At this time, the bonding parts BP22 and BP24 are prevented from being attached with foreign matter or scratched, so that the bonding defects between the bonding parts BP22 and BP24 are prevented. In such a structure in which the substrate W1 of the so-called intermediate layer is sealed by the upper and lower substrates W2 and W3, in a MEMS device in which a part of the substrate W1 of the intermediate layer is a pressure sensor, an acceleration sensor, a vibrator, or the like, the upper and lower substrates W2 and W3 seal the cavity in a vacuum state or the like. In this case, when bonding the substrates W1 and W2, if the bonding part BP22 provided on the side of the substrate W1 to be bonded to the substrate W3 comes into contact with the stage 141 of the first bonding apparatus 1, scratches, dirt, etc. may adhere to the bonding part BP22, which may affect the sealing state. For this reason, it is effective to provide a recess 141c in the stage 141 so that the portion P2 of the substrate W1 where the bonding part BP22 is formed does not come into contact with the stage 141, and to temporarily bond the bonding parts BP26 and BP28 formed from metal on the peripheral parts of the substrates W1 and W3 to each other.

[0073] In the embodiment, the load lock unit 83 may have, for example, a four-stage cassette (not shown) for storing the substrates W1, W2, and W3, and a substrate jig 835 that can be transported by the transport device 84 and holds the substrate W1, as shown in FIG. 27A. The substrate jig 835 is a member for holding an object to be bonded, with a recess 835a provided on the inside. In this case, as shown by the arrow AR101 in FIG. 27A, the bonding system first takes out the three substrates W1', W2', and W3' bonded to each other with the load lock unit 83 open to the atmosphere, and inserts the substrate W2 into the cassette with its bonding surface facing vertically downward, as shown by the arrow AR102. Also, as shown by the arrow AR103, the substrate W1 is placed on the substrate jig 835 inserted into the cassette, and the substrate W3 is inserted into the cassette with its bonding surface facing vertically upward, as shown by the arrow AR104. Next, after the load lock unit 83 is put into a vacuum state, the transport device 84 transports the substrate W2 to the first bonding apparatus 1 as shown by the arrow AR105 in FIG. 27B, and the first bonding apparatus 1 holds the substrate W2 on the head 142. Next, the transport device 84 transports the substrate W1 placed on the substrate jig 835 to the first bonding apparatus 1 together with the substrate jig 835 as shown by the arrow AR106, and the first bonding apparatus 1 holds the substrate jig 835 on which the substrate W1 is placed on the stage 141. Thereafter, the first bonding apparatus 1 temporarily bonds the substrates W1 and W2 to each other. Next, the first bonding apparatus 1 raises the head 142 while the substrates W1 and W2 temporarily bonded to each other are adsorbed and held by the head 142, and leaves the substrate jig 835 on the stage 141, as shown in FIG. 28A. Then, as shown by an arrow AR107, the transport device 84 transports only the substrate jig 835 to the load lock section 83. Thereafter, as shown by an arrow AR108 in FIG. 28B, the transport device 84 transports the substrate W3 to the first bonding apparatus 1, which then holds the substrate W3 on the stage 141. Next, the first bonding apparatus 1 temporarily or permanently bonds the substrates W1, W2 and W3 that have been temporarily bonded to each other. Then, as shown by an arrow AR109 in FIG. 29, the transport device 84 transports the substrates W1, W2, and W3 that have been temporarily bonded to each other from the first bonding apparatus 1 to the load lock section 83. Thereafter, the series of operations described above with reference to FIGS. 27A to 29 are repeatedly executed.Note that, here, an example has been described in which the substrate W1, which is so-called in the middle, is placed on the substrate jig 835, but the present invention is not limited to this, and for example, the substrate jig 835 may be a substrate W2 to be joined to the upper side of the substrate W1. If the substrate W2 is thin and warped, it may come into point contact with the electrostatic chuck of the head 142, which may result in the substrate W2 not being firmly held. In response to this, by pressing the substrate W2 against the head 142 while it is placed on the substrate jig 835, the warping is forcibly removed, and the substrate W2 is firmly attracted and held by the electrostatic chuck.

[0074] Incidentally, when the recess 141c is provided in the stage 141, only the peripheral portions of the substrates W1, W2, and W3 can be temporarily bonded in the temporary bonding process performed by the first bonding apparatus 1. For this reason, after the temporary bonding process is performed, the substrates need to be transported to the second bonding apparatuses 2A and 2B, and a main bonding process needs to be performed in the second bonding apparatuses 2A and 2B using a flat stage 241.

[0075] In contrast, according to the present configuration using the substrate jig 835, when a plurality of substrates W1, W2, and W3 are bonded to each other, the substrate W1 located in the middle is held only at its periphery by the substrate jig 835, which prevents the bonding portion of the substrate W1 provided on the substrate jig 835 side from being scratched or having foreign matter attached thereto, and the substrates W1 and W2 can be temporarily bonded only at their periphery. In addition, when the substrate W3 is further bonded to the substrates W1 and W2 temporarily bonded to each other, pressure can be applied to the entire surfaces of the substrates W1, W2, and W3, so that the main bonding process can be performed only with the first bonding device 1. Therefore, the second bonding devices 2A and 2B are not required, and the configuration of the bonding system can be simplified.

[0076] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. The above-described embodiments are for the purpose of explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and the scope of the invention equivalent thereto are considered to be within the scope of the present invention.

[0077] This application is based on Japanese Patent Application No. 2022-044957 filed on March 22, 2022. The entire specification, claims and drawings of Japanese Patent Application No. 2022-044957 are incorporated herein by reference. [Industrial Applicability]

[0078] The present invention is suitable for manufacturing MEMS (Micro Electro Mechanical Systems) such as pressure sensors, acceleration sensors, and vibrators. [Explanation of symbols]

[0079] 1: first bonding device, 2A, 2B: second bonding device, 9: control unit, 82, 84: transport device, 83: load lock unit, 120, 220, 831: chamber, 121: window unit, 121a, 221a: vacuum pump, 121b, 221b: exhaust pipe, 121c, 221c: exhaust valve, 122A, 122B: cover, 123A, 123B: cover heating unit, 141, 241, 2141: stage, 141c, 142c: recess, 142, 242, 2142: head, 143, 243: stage drive unit, 144, 244: head drive unit, 150: position deviation amount measurement unit, 161, 162: particle beam source, 811, 812, 813: introduction port, 814: removal port, 821, 841: transfer robot, 832, 833: gate, 1 411, 1421, 2411, 2421: substrate heating unit, 1441, 2441: lifting drive unit, 1441a, 1445, 2441a: pressure sensor, 1442, 2442: XY direction drive unit, 1443, 2443: rotation drive unit, 1444, 2444: piezo actuator, 1446, 2446: distance measurement unit, 1501: first imaging unit, 1502: second imaging unit, 1504, 1505: mirrors, 1601: discharge chamber, 1601a: FAB emission port, 1602: electrode, 1603: beam source drive unit, 1604: gas supply unit, BP11, BP12, BP21, BP22, BP23, BP24: joints, SP1: gap, MK1a, MK1b, MK2a, MK2b: alignment marks, W1, W2, W1', W2', W3: substrates

Claims

1. A joining system for joining a plurality of workpieces to each other, comprising: a first bonding device that performs a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by bringing the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a second bonding device for performing a final bonding process in which the plurality of objects to be bonded are heated to a final bonding temperature, which is higher than the temporary bonding temperature during the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby performing a final bonding process in which the plurality of objects to be bonded are bonded together; a conveying device that conveys the plurality of workpieces temporarily joined to each other from the first joining device to the second joining device while maintaining a reduced pressure state, The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, In the main joining step, main joining is performed on the first joining portion and the second joining portion that are the same as the first joining portion and the second joining portion that are temporarily joined in the temporary joining step, The temperature difference between the start and end of pressure application in the temporary bonding step and the main bonding step is 100° C. or less. Joining system.

2. A joining system for joining a plurality of workpieces to each other, comprising: a first bonding device that performs a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by bringing the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a second bonding device for performing a final bonding process in which the plurality of objects to be bonded are heated to a final bonding temperature, which is higher than the temporary bonding temperature during the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby performing a final bonding process in which the plurality of objects to be bonded are bonded together; a conveying device that conveys the plurality of workpieces temporarily joined to each other from the first joining device to the second joining device while maintaining a reduced pressure state, The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, the first joining device performs the temporary joining step on the first workpiece and the second workpiece such that the first joining portion and the second joining portion are in contact with each other; the second bonding device heats the first and second objects to be bonded temporarily to a final bonding temperature that is higher than a temporary bonding temperature at the time of the temporary bonding, and applies pressure to the first and second objects to be bonded in a direction in which they approach each other, thereby diffusing metal atoms forming at least one of the first bonding portion and the second bonding portion in a solid phase to bond the first and second bonding portions, The calculated average roughness of the surface of the first bonding portion and the second bonding portion is greater than 0.5 nm; Joining system.

3. the first joining device performs the temporary joining step on the first workpiece and the second workpiece such that the first joining portion and the second joining portion are in contact with each other; the second bonding device heats the first and second objects to be bonded, which are temporarily bonded to each other, to a final bonding temperature that is higher than a temporary bonding temperature at the time of the temporary bonding, and applies pressure to the first and second objects to be bonded in a direction in which they approach each other, thereby diffusing metal atoms forming at least one of the first bonding portion and the second bonding portion in a solid phase to bond the first and second bonding portions, The joint system of claim 1 .

4. The temperature difference between the temporary bonding temperature and the main bonding temperature is 200°C or less. The joint system according to claim 1 or 2.

5. The first object to be bonded has a contour shape and at least one first bonding portion is formed on a first main surface side in a thickness direction, The second object to be bonded has a contour shape and at least one second bonding portion is formed on a second main surface side in a thickness direction, a space formed between the first main surface and the second main surface of the first object to be bonded and surrounded by the first bonding portion and the second bonding portion in a contour shape is sealed; The joint system according to claim 1 or 2.

6. the first object to be bonded is plate-shaped and has at least one of the first bonding portions on one surface side in a thickness direction and at least one of the third bonding portions on the other surface side; The plurality of objects to be bonded further includes a third object to be bonded having a fourth bonding portion to be bonded to the third bonding portion. The joint system according to claim 1 or 2.

7. A joining system for joining a plurality of workpieces to each other, comprising: a first bonding device that performs a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by bringing the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a second bonding device for performing a final bonding process in which the plurality of objects to be bonded are heated to a final bonding temperature, which is higher than the temporary bonding temperature during the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby performing a final bonding process in which the plurality of objects to be bonded are bonded together; a conveying device that conveys the plurality of workpieces temporarily joined to each other from the first joining device to the second joining device while maintaining a reduced pressure state, The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, The first joining device is A second object holding portion that holds the second object to be bonded; a first object holding portion for holding the first object, in a state in which the first joining portion of the first object faces the second joining portion of the second object and is in contact with only a peripheral portion of the first object directly or via an object holding member for holding the first object; Joining system.

8. A load lock unit having a chamber in which the plurality of objects to be bonded are placed, the transport device has a workpiece holding member for holding at least one workpiece arranged in the chamber, transports the at least one workpiece placed on the workpiece holding member together with the workpiece holding member to the first bonding device, and then transports the workpiece holding member into the chamber. The joint system according to any one of claims 1, 2 and 7.

9. The metal is Au or Cu; The joint system according to any one of claims 1, 2 and 7.

10. The metal is Au. The joint system of claim 9.

11. the transport device transports the plurality of workpieces temporarily bonded to each other from the first bonding device to the second bonding device while maintaining a state of a vacuum degree higher than 1000 Pa. The joint system according to any one of claims 1, 2 and 7.

12. the second bonding device raises the temperatures of the objects to be bonded from a state in which the objects are maintained at a temperature lower than the main bonding temperature and the temperature difference from the main bonding temperature is 200° C. or less, and causes the temperatures of the objects to reach the main bonding temperature, and then performs the main bonding. The joint system according to any one of claims 1, 2 and 7.

13. The temporary bonding temperature is 150° C. or less, The main bonding temperature is 250° C. or less. The joint system according to any one of claims 1, 2 and 7.

14. The temporary bonding temperature is 60° C. or less. The joint system of claim 13.

15. The bonding portion of each of the plurality of objects to be bonded is activated by an activation treatment device. The joint system according to any one of claims 1, 2 and 7.

16. The first bonding device has an activation processing unit that performs an activation process to activate at least one of the bonding portions of each of the plurality of objects to be bonded. The joint system according to any one of claims 1, 2 and 7.

17. In the activation treatment, at least one of the bonding portions of each of the plurality of objects to be bonded is exposed to plasma. The joint system of claim 15.

18. In the activation treatment, a particle beam is irradiated onto at least one of the bonding portions of each of the plurality of objects to be bonded. The joint system of claim 16.

19. The activation processing unit has a fast atom beam source that irradiates a particle beam having a preset energy onto at least one of the bonding portions of each of the plurality of objects to be bonded. The joint system of claim 16.

20. At least one of two bonding portions to be bonded to each other, selected from the bonding portions of each of the plurality of objects to be bonded, is heated to the temporary bonding temperature and then the activation treatment is performed. The joint system of claim 16.

21. A joining system for joining a plurality of workpieces to each other, comprising: a first bonding device that performs a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by bringing the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a second bonding device for performing a final bonding process in which the plurality of objects to be bonded are heated to a final bonding temperature, which is higher than the temporary bonding temperature during the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby performing a final bonding process in which the plurality of objects to be bonded are bonded together; a conveying device that conveys the plurality of workpieces temporarily joined to each other from the first joining device to the second joining device while maintaining a reduced pressure state, A plurality of the second joining devices are provided, the transport device transports the plurality of workpieces temporarily bonded to each other from the first bonding device to a second bonding device which is not performing the main bonding step, among the plurality of second bonding devices, while maintaining a reduced pressure state. Joining system.

22. A method for joining a plurality of objects to be joined, comprising the steps of: a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by contacting the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of the two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a final bonding process in which the temperature of the plurality of objects to be bonded temporarily to each other is heated to a final bonding temperature, which is a temperature higher than the temporary bonding temperature at the time of the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby final bonding the plurality of objects to be bonded together; The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, In the main joining step, main joining is performed on the first joining portion and the second joining portion that are the same as the first joining portion and the second joining portion that are temporarily joined in the temporary joining step, The temperature difference between the start and end of pressure application in the temporary bonding step and the main bonding step is 100° C. or less. Joining method.

23. A method for joining a plurality of workpieces, comprising the steps of: a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by contacting the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of the two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a final bonding process in which the temperature of the plurality of objects to be bonded temporarily to each other is heated to a final bonding temperature, which is a temperature higher than the temporary bonding temperature at the time of the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby final bonding the plurality of objects to be bonded together; The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, In the temporary joining step, the first and second objects are temporarily joined together such that the first and second joining portions are in contact with each other; In the main bonding step, the temperature of the first and second objects to be bonded temporarily to each other is heated to a main bonding temperature that is higher than a temporary bonding temperature at the time of the temporary bonding, and pressure is applied to the first and second objects to be bonded in a direction in which they approach each other, thereby diffusing metal atoms forming at least one of the first bonding portion and the second bonding portion in a solid phase to main bond the first and second bonding portions; The calculated average roughness of the surface of the first bonding portion and the second bonding portion is greater than 0.5 nm; Joining method.

24. The temperature difference between the temporary bonding temperature and the main bonding temperature is 200°C or less. The bonding method according to claim 22 or 23.

25. The first object to be bonded has a contour shape and at least one first bonding portion is formed on a first main surface side in a thickness direction, The second object to be bonded has a contour shape and at least one second bonding portion is formed on a second main surface side in a thickness direction, a space formed between the first main surface and the second main surface of the first object to be bonded and surrounded by the first bonding portion and the second bonding portion in a contour shape is sealed; The bonding method according to claim 22 or 23.

26. the first object to be bonded is a substrate, and has at least one of the first bonding portions on one surface side in a thickness direction and at least one of the third bonding portions on the other surface side; The plurality of objects to be bonded further includes a third object to be bonded having a fourth bonding portion to be bonded to the third bonding portion. The bonding method according to claim 22 or 23.

27. A method for joining a plurality of objects to be joined, comprising the steps of: a temporary bonding process in which the multiple objects to be bonded are temporarily bonded to each other by contacting the bonding portions of the multiple objects to be bonded together under reduced pressure while at least one of the two bonding portions selected from the bonding portions of each of the multiple objects to be bonded to each other is activated; a final bonding process in which the temperature of the plurality of objects to be bonded temporarily to each other is heated to a final bonding temperature, which is a temperature higher than the temporary bonding temperature at the time of the temporary bonding, under reduced pressure, and pressure is applied to the plurality of objects to be bonded in a direction in which the objects approach each other, thereby final bonding the plurality of objects to be bonded together; The plurality of objects to be bonded include a first object to be bonded having at least one first bonding portion formed from a metal, and a second object to be bonded having at least one second bonding portion formed from a metal, In the temporary joining step, the first and second objects are temporarily joined together such that the first and second joining portions are in contact with each other; In the main bonding step, the temperature of the first and second objects to be bonded temporarily to each other is heated to a main bonding temperature that is higher than a temporary bonding temperature at the time of the temporary bonding, and pressure is applied to the first and second objects to be bonded in a direction in which they approach each other, thereby diffusing metal atoms forming at least one of the first bonding portion and the second bonding portion in a solid phase to main bond the first and second bonding portions; In the temporary joining step, only a peripheral portion of the first workpiece is held in a state in which the first joining portion of the first workpiece faces the second joining portion of the second workpiece. Joining method.

28. In the main bonding step, the temperature of the plurality of objects to be bonded is raised from a state in which the temperature of the plurality of objects to be bonded is lower than the main bonding temperature and the temperature difference from the main bonding temperature is 200° C. or less, and the temperature of the plurality of objects to be bonded is made to reach the main bonding temperature, and then the main bonding is performed. The bonding method according to any one of claims 22, 23 and 27.

29. The temporary bonding temperature is 150° C. or less, The main bonding temperature is 250° C. or less. The bonding method according to any one of claims 22, 23 and 27.

30. The temporary bonding temperature is 60° C. or less. The bonding method according to claim 29.

31. The method further includes an activation treatment step of activating, under reduced pressure, at least one of two bonding portions to be bonded to each other, selected from the bonding portions of each of the plurality of objects to be bonded. The bonding method according to any one of claims 22, 23 and 27.

32. The method further includes an activation process of irradiating at least one of the bonding portions of each of the plurality of objects to be bonded with a particle beam to activate at least one of the bonding portions of each of the plurality of objects to be bonded. The bonding method according to any one of claims 22, 23 and 27.

33. a workpiece holding step of holding at least one workpiece on a workpiece holding member for holding at least one workpiece arranged in a first chamber of a load lock part having the first chamber in which the plurality of workpieces are arranged; a first conveying step of conveying the at least one workpiece placed on the workpiece holding member together with the workpiece holding member into a second chamber in which the temporary bonding step is performed; a second conveying step of conveying the object holding member into the first chamber after the first conveying step, The bonding method according to any one of claims 22, 23 and 27.

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