Bonding method and bonding system

Abstract

To provide a technique capable of suppressing deterioration of a bonding strength.SOLUTION: A bonding method according to an aspect of a present disclosure includes steps of: preparing a first semiconductor substrate having a first surface and a second semiconductor substrate having a second surface; performing hydrophilization of the first surface of the first semiconductor substrate and the second surface of the second semiconductor substrate; bonding the first surface of the first semiconductor substrate and the second surface of the second semiconductor substrate after the hydrophilization; and enhancing a bonding strength of the first and second semiconductor substrates by performing a heat treatment to the first and second semiconductor substrates after the bonding. The enhancement of the bonding strength contains steps of: performing the heat treatment of the first and second semiconductor substrates within a first temperature range; and performing the heat treatment of the first and second semiconductor substrates at a target temperature after the heat treatment in the first temperature range. The temperatures in the first temperature range are lower than the target temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] There is known a technique in which two semiconductor wafers are bonded together for temporary bonding, and then heat-treated at high temperature (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-103291 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique capable of suppressing a decrease in bonding strength. [Means for solving the problem]

[0005] A bonding method according to one aspect of the present disclosure includes preparing a first semiconductor substrate having a first surface and a second semiconductor substrate having a second surface; hydrophilizing the first surface of the first semiconductor substrate and the second surface of the second semiconductor substrate; bonding the first surface of the first semiconductor substrate and the second surface of the second semiconductor substrate after the hydrophilizing; and heat-treating the first semiconductor substrate and the second semiconductor substrate after the bonding, thereby increasing a bonding strength between the first semiconductor substrate and the second semiconductor substrate, wherein the increasing the bonding strength includes heat-treating the first semiconductor substrate and the second semiconductor substrate in a first temperature range; and after heat-treating in the first temperature range, heat-treating the first semiconductor substrate and the second semiconductor substrate at a target temperature, wherein the first temperature range is a temperature range lower than the target temperature. Effect of the Invention

[0006] According to the present disclosure, it is possible to suppress a decrease in bonding strength. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a joint system according to a first embodiment. [Diagram 2] FIG. 2 is a flowchart showing the bonding method according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing an example of a first die carrier and a die. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the second die carrier. [Diagram 5] FIG. 5 is a cross-sectional view showing an example of a second die carrier and a die. [Figure 6] FIG. 6 is a cross-sectional view showing an example of a substrate. [Figure 7] FIG. 7 is a cross-sectional view showing an example of a substrate with a die. [Figure 8] FIG. 8 is a cross-sectional view showing an example of the operation of the die arrangement device. [Figure 9] FIG. 9 is a cross-sectional view showing an example of electrostatic adsorption. [Figure 10] FIG. 10 is a cross-sectional view showing an example of the operation of the joining device. [Figure 11] FIG. 11 is a cross-sectional view showing an example of the operation subsequent to that shown in FIG. [Figure 12] FIG. 12 is a diagram showing an example of the change over time of the controlled temperature during heat treatment. [Figure 13] FIG. 13 is a diagram showing another example of the change over time of the controlled temperature during heat treatment. [Figure 14] FIG. 14 is a plan view showing the system according to the second embodiment. [Figure 15] FIG. 15 is a cross-sectional view showing an example of the overlapping wafer. [Figure 16] FIG. 16 is a flowchart showing the bonding method according to the second embodiment. [Figure 17] FIG. 17 is a cross-sectional view showing an example of a bonding apparatus. [Figure 18] FIG. 18 is a cross-sectional view showing an example of the operation of the joining device. [Figure 19] FIG. 19 is a cross-sectional view showing an example of the operation subsequent to that shown in FIG. [Figure 20] FIG. 20 is a cross-sectional view showing an example of the operation subsequent to that shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all the accompanying drawings, the same or corresponding members or parts are denoted by the same or corresponding reference symbols, and duplicated descriptions are omitted. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is vertical.

[0009] [First embodiment] (Joint System) A bonding system 1 according to a first embodiment will be described with reference to Fig. 1 to Fig. 11. As shown in Fig. 7, the bonding system 1 manufactures a die-attached substrate CW by bonding a die CP and a substrate W. The die CP is an example of a first semiconductor substrate, and the substrate W is an example of a second semiconductor substrate. The die-attached substrate CW includes the substrate W and a plurality of dies CP bonded to the substrate W.

[0010] The die CP has a base substrate S1 and a device D1 formed on the base substrate S1. The base substrate S1 is, for example, a silicon wafer, a compound semiconductor wafer, or a glass substrate. The device D1 includes a semiconductor element, a circuit, a terminal, or the like. The device D1 is formed on a bonding surface CPa of the die CP.

[0011] The substrate W includes a base substrate S2 and a plurality of devices D2 formed on the base substrate S2. The base substrate S2 is, for example, a silicon wafer, a compound semiconductor wafer, or a glass substrate. The devices D2 include semiconductor elements, circuits, terminals, or the like. The devices D2 are formed on a bonding surface Wa of the substrate W.

[0012] The device D1 of the die CP and the device D2 of the substrate W are electrically connected. Although not shown, a plurality of devices D1 may be electrically connected to one device D2. The plurality of devices D1 may have different functions, that is, different electric circuits. The device D1 of one die CP may be electrically connected to the device D2 of the substrate W via the device D1 of another die CP.

[0013] 1, the bonding system 1 includes a loading / unloading station 2, a processing station 3, and a control device 9. The loading / unloading station 2 and the processing station 3 are arranged in this order from the negative side of the X-axis to the positive side of the X-axis.

[0014] The carry-in / out station 2 includes a mounting table 20. Cassettes C1 to C6 are mounted on the mounting table 20. Cassette C1 accommodates a plurality of dies CP held by a first die carrier FC. Cassette C2 accommodates a used first die carrier FC from which at least some of the dies CP have been removed. Cassettes C3 and C4 accommodate second die carriers SC. Cassette C5 accommodates a substrate W prior to bonding with a die CP. Cassette C6 accommodates a substrate CW with a die attached.

[0015] As shown in Fig. 3, the first die carrier FC has a tape TP to which the die CP is adhered, and a frame FR to which the outer periphery of the tape TP is adhered. A plurality of dies CP are arranged in an opening of the frame FR. The plurality of dies CP are obtained, for example, by dicing a substrate in a state in which the substrate is adhered to the tape TP. A bonding surface CPa of the die CP is protected by a protective film PF before dicing. The protective film PF is disposed on the opposite side of the die CP from the tape TP. The protective film PF is removed before bonding the die CP to the substrate W.

[0016] The second die carrier SC holds the multiple dies CP removed from the first die carrier FC as shown in Fig. 5. The second die carrier SC is, for example, an electrostatic carrier. The electrostatic carrier electrostatically adsorbs the multiple dies CP. The electrostatic carrier may electrostatically adsorb the multiple dies CP and also vacuum adsorb them. Even after the electrostatic adsorption force disappears, the multiple dies CP can continue to be held by the vacuum adsorption force.

[0017] In this embodiment, the second die carrier SC holds multiple die CPs having the same function, but may hold multiple die CPs having different functions. In the latter case, multiple first die carriers FC are prepared according to the function of the die CP. It is also possible to transfer multiple die CPs having different functions from multiple first die carriers FC to one second die carrier SC.

[0018] The die CP is transferred from the first die carrier FC to the second die carrier SC in order to remove the protective film PF from the die CP and modify the bonding surface CPa of the die CP before bonding the die CP to the substrate W. This is to prevent the tape TP of the first die carrier FC from being damaged during the modification of the bonding surface CPa. The details of the second die carrier SC will be described later.

[0019] 1, the loading / unloading station 2 includes a transfer area 21, a first die carrier transfer arm 22, a second die carrier transfer arm 23, and a substrate transfer arm 24. Hereinafter, the first die carrier transfer arm 22, the second die carrier transfer arm 23, and the substrate transfer arm 24 may be collectively referred to as transfer arms 22-24.

[0020] The transfer region 21 is adjacent to the mounting table 20. The transfer arms 22-24 hold and transfer the first die carrier FC, the second die carrier SC, or the substrate W in the transfer region 21. The transfer arms 22-24 are each capable of moving in the horizontal direction (both the X-axis and Y-axis directions) and the vertical direction, and of rotating about a vertical axis.

[0021] The transport device is made up of the transport arms 22 to 24 and a drive unit (not shown) that moves or rotates the transport arms 22 to 24. The transport arms 22 to 24 may be mounted on the same Y-axis slider and moved simultaneously in the Y-axis direction as shown in Fig. 1, or may be mounted on different Y-axis sliders and moved independently in the Y-axis direction. The transport arms 22 to 24 are disposed at different heights.

[0022] The loading / unloading station 2 includes a transition device 25 on the opposite side to the mounting table 20 across the transfer area 21. The transition device 25 is provided between the transfer area 21 of the loading / unloading station 2 and the transfer area 31 of the processing station 3, and relays the first die carrier FC, the second die carrier SC, or the substrate W between them. A plurality of transition devices 25 may be stacked in the Z-axis direction.

[0023] The processing station 3 includes a transfer area 31, a first die carrier transfer arm 32, a second die carrier transfer arm 33, and a substrate transfer arm 34. Hereinafter, the first die carrier transfer arm 32, the second die carrier transfer arm 33, and the substrate transfer arm 34 may be collectively referred to as transfer arms 32-34.

[0024] The transfer region 31 extends in the X-axis direction. The transfer arms 32 to 34 hold and transfer the first die carrier FC, the second die carrier SC, or the substrate W in the transfer region 31. The transfer arms 32 to 34 are each capable of moving in the horizontal direction (both in the X-axis direction and the Y-axis direction) and the vertical direction, and of rotating about a vertical axis.

[0025] The transport device is made up of the transport arms 32 to 34 and a drive unit (not shown) that moves or rotates the transport arms 32 to 34. The transport arms 32 to 34 may be mounted on the same X-axis slider and moved simultaneously in the X-axis direction as shown in Fig. 1, or may be mounted on different X-axis sliders and moved independently in the X-axis direction. The transport arms 32 to 34 are disposed at different heights.

[0026] The processing station 3 includes a die arrangement device 35, a cleaning device 36, a first activation device 37, a first hydrophilization device 38, an inversion device 39, a second activation device 40, a second hydrophilization device 41, a bonding device 42, and an annealing device 43. These devices 35 to 43 are adjacent to the transport region 31, and are disposed on the Y-axis positive direction side or the Y-axis negative direction side of the transport region 31, respectively.

[0027] The die arrangement device 35 transfers the die CP from the first die carrier FC to the second die carrier SC as shown in Fig. 8. This makes it possible to prevent damage to the tape TP of the first die carrier FC when modifying the bonding surface CPa. The details of the die arrangement device 35 will be described later.

[0028] The cleaning device 36 removes the protective film PF from the die CP while the die CP is held by the second die carrier SC. The cleaning device 36 also cleans the bonding surface CPa of the die CP. This can improve the quality of the processing of the bonding surface CPa that is performed thereafter.

[0029] The first activation device 37 activates the bonding surface CPa of the die CP while the die CP is held by the second die carrier SC. The first activation device 37 is, for example, a plasma processing device. In the first activation device 37, oxygen gas, which is a processing gas, is excited under reduced pressure, for example, to be turned into plasma and ionized. The bonding surface CPa of the die CP is activated by irradiating the oxygen ions onto the bonding surface CPa of the die CP. The processing gas is not limited to oxygen gas, and may be, for example, nitrogen gas or the like.

[0030] The first hydrophilizing device 38 hydrophilizes the bonding surface CPa of the die CP while the die CP is held by the second die carrier SC. For example, the first hydrophilizing device 38 supplies pure water (e.g., deionized water) onto the die CP while rotating the second die carrier SC held by the spin chuck. The pure water provides OH groups (silanol groups) to the bonding surface CPa of the die CP, which has been activated in advance. The die CP and the substrate W can be bonded by utilizing hydrogen bonds between the OH groups.

[0031] The inversion device 39 inverts the second die carrier SC upside down while the die CP is held by the second die carrier SC. A plurality of dies CP can be inverted upside down all at once, and the joining surface CPa of each die CP can face downward. The inversion device 39 may be provided inside the joining device 42.

[0032] The second activation device 40 activates the bonding surface Wa of the substrate W. The second activation device 40 is, for example, a plasma processing device. In the second activation device 40, oxygen gas, which is a processing gas, is excited, for example, under reduced pressure, and turned into plasma and ionized. The bonding surface Wa of the substrate W is activated by irradiating the oxygen ions onto the bonding surface Wa of the substrate W. The processing gas is not limited to oxygen gas, and may be, for example, nitrogen gas or the like.

[0033] The second hydrophilization device 41 hydrophilizes the bonding surface Wa of the substrate W. For example, the second hydrophilization device 41 supplies pure water (e.g., deionized water) onto the substrate W while rotating the substrate W held by the spin chuck. The pure water imparts OH groups to the bonding surface Wa of the substrate W, which has been activated in advance. The die CP and the substrate W can be bonded by utilizing hydrogen bonds between the OH groups.

[0034] 10 and 11, the bonding device 42 removes the die CP from the second die carrier SC, and bonds the die CP to the substrate W by orienting the bonding surface CPa of the removed die CP toward the bonding surface Wa of the substrate W. A substrate CW with a die is obtained. The device D1 of the die CP and the device D2 of the substrate W are electrically connected. The bonding device 42 will be described in detail later.

[0035] The annealing device 43 heat-treats the die-attached substrate CW. Before the heat treatment, the die CP and the substrate W are bonded by hydrogen bonds between OH groups. The heat treatment causes a dehydration condensation reaction, which generates covalent bonds, improving the bonding strength between the die CP and the substrate W. The annealing devices 43 are stacked, for example, in the Z-axis direction. The multiple annealing devices 43 are configured to heat-treat the die-attached substrate CW at different set temperatures. The multiple annealing devices 43 include an annealing device whose set temperature is a target temperature and an annealing device whose set temperature is in a first temperature range lower than the target temperature. The target temperature is a temperature at which a dehydration condensation reaction occurs and covalent bonds are formed. The target temperature is, for example, 350° C. or higher. In this embodiment, the multiple annealing devices 43 include five annealing devices 43a to 43e. The annealing devices 43a, 43b, 43c, 43d, and 43e have set temperatures of 50° C., 100° C., 150° C., 200° C., and 350° C. (target temperatures), respectively. The number of annealing devices 43 is not limited to that shown in the figure.

[0036] The control device 9 is, for example, a computer, and includes an arithmetic unit 91 such as a CPU (Central Processing Unit) and a storage unit 92 such as a memory. The storage unit 92 stores programs that control various processes executed in the bonding system 1. The control device 9 controls the operation of the bonding system 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92. A unit control unit that controls the operation of each unit constituting the bonding system 1 may be provided, and a system control unit that controls a plurality of unit control units may be provided. The control device 9 may be configured of the unit control units and the system control unit.

[0037] (Joining method) The joining method according to the first embodiment will be described with reference to Fig. 2. The process of Fig. 2 is performed under the control of the control device 9.

[0038] First, the first die carrier transport arm 22 takes out the multiple dies CP together with the first die carrier FC from the cassette C1 and transports them to the transition device 25. Next, the first die carrier transport arm 32 takes out the multiple dies CP together with the first die carrier FC from the transition device 25 and transports them to the die arrangement device 35.

[0039] Furthermore, the second die carrier transport arm 23 takes out the second die carrier SC from the cassette C3 and transports it to the transition device 25. Next, the second die carrier transport arm 33 takes out the second die carrier SC from the transition device 25 and transports it to the die arrangement device 35.

[0040] Next, the die arrangement device 35 transfers the die CP from the first die carrier FC to the second die carrier SC (step S101). After that, the second die carrier transport arm 33 takes out the multiple dies CP together with the second die carrier SC from the die arrangement device 35 and transports them to the cleaning device 36.

[0041] Next, the cleaning device 36 removes the protective film PF from the die CP while the die CP is held by the second die carrier SC (step S102). After that, the second die carrier transport arm 33 takes out the multiple dies CP together with the second die carrier SC from the cleaning device 36 and transports them to the first activation device 37.

[0042] Next, the first activation device 37 activates the bonding surface CPa of the die CP while the die CP is held by the second die carrier SC (step S103). After that, the second die carrier transport arm 33 takes out the multiple dies CP together with the second die carrier SC from the first activation device 37 and transports them to the first hydrophilization device .

[0043] Next, the first hydrophilization device 38 hydrophilizes the bonding surface CPa of the die CP while the die CP is held by the second die carrier SC (step S104). After that, the second die carrier transport arm 33 takes out the multiple dies CP together with the second die carrier SC from the first hydrophilization device 38 and transports them to the inversion device 39.

[0044] Next, the inverting device 39 turns the second die carrier SC upside down while the second die carrier SC holds the die CP (step S105). After that, the second die carrier transport arm 33 takes out the second die carrier SC and the multiple dies CP from the inverting device 39 and transports them to the bonding device 42.

[0045] In parallel with the above steps S101 to S105, the following steps S106 to S107 are performed. First, the substrate transport arm 24 takes out the substrate W from the cassette C5 and transports it to the transition device 25. Thereafter, the substrate transport arm 34 takes out the substrate W from the transition device 25 and transports it to the second activation device 40.

[0046] Next, the second activation device 40 activates the bonding surface Wa of the substrate W (step S106). Thereafter, the substrate transport arm 34 takes out the substrate W from the second activation device 40 and transports it to the second hydrophilization device 41.

[0047] Next, the second hydrophilicity treatment device 41 hydrophilizes the bonding surface Wa of the substrate W (step S107). After that, the substrate transport arm takes out the substrate W from the second hydrophilicity treatment device 41 and transports it to the bonding device .

[0048] Next, the bonding device 42 removes the die CP from the second die carrier SC, and bonds the die CP to the substrate W with the bonding surface CPa of the removed die CP facing the bonding surface Wa of the substrate W (step S108). This results in a substrate CW with the die attached. Thereafter, the substrate transport arm 34 removes the substrate CW with the die attached from the bonding device 42 and transports it to the annealing device 43.

[0049] Next, the annealing device 43 heat-treats the die-attached substrate CW (step S109). This improves the bonding strength between the die CP and the substrate W. Details of the heat treatment will be described later. Thereafter, the substrate transport arm 34 takes out the die-attached substrate CW from the annealing device 43 and transports it to the transition device 25. Finally, the substrate transport arm 24 takes out the die-attached substrate CW from the transition device 25 and stores it in the cassette C6. The die-attached substrate CW is transported out of the bonding system 1 while still stored in the cassette C6.

[0050] After step S101, the first die carrier transport arm 32 takes out the first die carrier FC from the die arrangement device 35 and transports it to the transition device 25. After that, the first die carrier transport arm 22 takes out the first die carrier FC from the transition device 25 and stores it in the cassette C2.

[0051] Furthermore, after step S108, the second die carrier transport arm 33 takes out the second die carrier SC from the bonding device 42 and transports it to the transition device 25. Thereafter, the second die carrier transport arm 23 takes out the second die carrier SC from the transition device 25 and stores it in a cassette C4.

[0052] (Die Array Equipment) The die arrangement device 35 and the second die carrier SC will be described in detail with reference to Figures 8 and 9. As shown in Figure 8, the die arrangement device 35 transfers the die CP from the first die carrier FC to the second die carrier SC. This allows the use of a die carrier with relatively excellent durability when modifying the bonding surface CPa.

[0053] The second die carrier SC is not particularly limited as long as it has superior durability compared to the first die carrier FC, but may be, for example, an electrostatic carrier. The electrostatic carrier has, for example, a conductive substrate SC1 and an insulating film SC2, and electrostatically attracts the die CP to the opposite side of the insulating film SC2 from the conductive substrate SC1.

[0054] The conductive substrate SC1 is made of, for example, silicon, aluminum, an aluminum alloy, stainless steel, or titanium. The conductive substrate SC1 may have one or more through holes H1 formed for each die CP. The die CP can be peeled off from the second die carrier SC by supplying gas to the through holes H1 or by inserting a pin (not shown) into the through holes H1. The number and arrangement of the through holes H1 are not particularly limited.

[0055] The insulating film SC2 maintains the electrostatic adsorption force by restricting the movement of charges between the base substrate S1 of the die CP and the conductive substrate SC1, as shown in Fig. 9. The insulating film SC2 preferably has a breakdown voltage of 30 kV or more, and more preferably has a breakdown voltage of 40 kV or more.

[0056] The insulating film SC2 is preferably made of a flexible material, specifically a material having an elastic modulus of 2 GPa or less, more preferably 0.5 GPa or less. From the viewpoint of durability when modifying the bonding surface CPa, for example, polyimide or EVA (ethylene-vinyl acetate copolymer) is used. The thickness of the insulating film SC2 is, for example, 10 μm.

[0057] The insulating film SC2 may have a through hole formed therein that communicates with the through hole H1 of the conductive substrate SC1. The diameter of the through hole of the insulating film SC2 is preferably smaller than the diameter of the through hole H1 of the conductive substrate SC1. The through hole may not be necessary. In this case, the die CP can be removed by expanding the insulating film SC2.

[0058] The second die carrier SC preferably has the same diameter as the substrate W. In this case, the second die carrier transport arm 23 and the substrate transport arm 24 can be of the same model number (i.e., the same dimensions and the same shape), which reduces costs. Similarly, the second die carrier transport arm 33 and the substrate transport arm 34, the first activation device 37 and the second activation device 40, or the first hydrophilization device 38 and the second hydrophilization device 41 can be of the same model number, which reduces costs. The size of the apparatus can also be suppressed.

[0059] 8, the die arrangement device 35 includes a first die carrier holding section 351, a pressing section 352, a second die carrier holding section 353, and a die transport mechanism 354. The first die carrier holding section 351 holds the first die carrier FC from below the first die carrier FC. The first die carrier FC holds the die CP with the bonding surface CPa of the die CP facing upward. The first die carrier holding section 351 holds the frame FR of the first die carrier FC, but does not hold the tape TP.

[0060] The pressing unit 352 locally presses the die CP through the tape TP and locally deforms the tape TP. The die CP can be pushed up individually, and when the die CP is picked up, the dies CP can be prevented from rubbing against each other. The pressing unit 352 and the first die carrier holding unit 351 can move relatively, and the position where the die CP is pushed up can be changed.

[0061] The second die carrier holding section 353 holds the second die carrier SC from below the second die carrier SC. The second die carrier SC holds the die CP with the joining surface CPa of the die CP facing upward. Similarly, the first die carrier FC holds the die CP with the joining surface CPa of the die CP facing upward. Therefore, the die transport mechanism 354 also transports the die CP with the joining surface CPa of the die CP facing upward. The die transport mechanism 354 does not turn the die CP upside down.

[0062] The die transport mechanism 354 has a suction head 355 that suctions the die CP. The suction head 355 is disposed above the die CP. The bonding surface CPa of the die CP is covered with a protective film PF, and the suction head 355 suctions the die CP via the protective film PF. The suction head 355 comes into contact with the protective film PF, but does not come into contact with the die CP. This makes it possible to suppress damage to the die CP.

[0063] 9, the die arrangement device 35 includes a charge supply unit 356 and a charge removal unit 358. The charge supply unit 356 applies a voltage to the conductive substrate SC1 to supply a charge of a first polarity (e.g., positive) to the conductive substrate SC1. The charge removal unit 358 removes the charge of the first polarity from the die CP to leave a charge of a second polarity (e.g., negative) opposite to the first polarity on the die CP.

[0064] Charges of a first polarity accumulate on the conductive substrate SC1, while charges of a second polarity accumulate on the die CP. As a result, a potential difference occurs between the conductive substrate SC1 and the die CP across the insulating film SC2, generating an electrostatic attraction force. The generated electrostatic attraction force is maintained even after the application of voltage to the conductive substrate SC1 and the de-electrification of the die CP are released.

[0065] The charge supply unit 356 has, for example, a power supply pin 357 that contacts the conductive substrate SC1. The power supply pin 357 is provided, for example, on the second die carrier holding unit 353 and is electrically connected to a power source (not shown). The charge removal unit 358 has, for example, a ground wire 359. The ground wire 359 removes the charge of the first polarity from the die CP via, for example, the protective film PF.

[0066] In this embodiment, the earth wire 359 is embedded in the suction head 355, but may be provided separately from the suction head 355. In this embodiment, the die CP is electrostatically attracted one by one, but a plurality of die CPs may be arranged on the insulating film SC2 and then electrostatically attracted simultaneously.

[0067] As described above, the insulating film SC2 is made of a flexible material. When the die CP is pressed against the insulating film SC2 by the electrostatic attraction force, the insulating film SC2 deforms so that air escapes from between the die CP and the insulating film SC2, and a vacuum attraction force is generated between the die CP and the insulating film SC2.

[0068] Even if the electrostatic adsorption force is lost due to charge leakage from the conductive substrate SC1 or the die CP, the multiple dies CP can continue to be held by the vacuum adsorption force. Examples of the cause of charge leakage include the supply of a treatment liquid to the die CP when removing the protective film PF or modifying the bonding surface CPa.

[0069] (Joining equipment) The bonding device 42 will be described in detail with reference to Figures 10 and 11. As shown in Figures 10 and 11, the bonding device 42 removes the die CP from the second die carrier SC, and bonds the die CP to the substrate W with the bonding surface CPa of the removed die CP facing the bonding surface Wa of the substrate W. A substrate CW with the die is obtained. The device D1 of the die CP and the device D2 of the substrate W are electrically connected.

[0070] The bonding device 42 includes, for example, a die carrier holding section 421, a substrate holding section 422, a first die transport mechanism 423, and a second die transport mechanism 424. The die carrier holding section 421 holds the second die carrier SC from above the second die carrier SC with the bonding surfaces CPa of the multiple dies CP held by the second die carrier SC facing downward. The substrate holding section 422 holds the substrate W from below the substrate W with the bonding surface Wa of the substrate W facing upward. The first die transport mechanism 423 receives the die CP from the second die carrier SC and transports the die CP with the bonding surface CPa of the die CP facing downward. The second die transport mechanism 424 receives the die CP from the first die transport mechanism 423 and bonds the die CP to the substrate W with the bonding surface CPa of the die CP facing downward.

[0071] According to this embodiment, before the die carrier holding unit 421 holds the second die carrier SC, the inversion device 39 inverts the second die carrier SC upside down. A plurality of dies CP can be inverted upside down all at once in advance, and the bonding surface CPa of each die CP can be directed downward. The first die transport mechanism 423 and the second die transport mechanism 424 do not invert the die CP upside down individually while transporting the die CP individually. The mechanism for inverting the die CP upside down individually can be eliminated, and dust generation from the mechanism can be suppressed. In addition, the structure of the first die transport mechanism 423 and the second die transport mechanism 424 can be simplified. Furthermore, the number of inversions can be reduced, and throughput can be improved.

[0072] According to this embodiment, the die carrier holding part 421 holds the second die carrier SC from above the second die carrier SC, and the substrate holding part 422 holds the substrate W from below the substrate W. By holding the substrate W, which is larger and heavier than the die CP, from below the substrate W, the substrate W can be stably held and the die CP can be bonded to the desired position of the substrate W. The accuracy of the bonding position is mainly determined by the alignment accuracy of the second die transport mechanism 424 and the substrate holding part 422. Compared to the alignment accuracy, the alignment accuracy of the first die transport mechanism 423 and the die carrier holding part 421 may be lower. Therefore, even if the die carrier holding part 421 holds the second die carrier SC from above the second die carrier SC, the accuracy of the bonding position does not deteriorate.

[0073] In this embodiment, the die carrier holding unit 421 holds the second die carrier SC, but may hold the first die carrier FC. If the bonding system 1 does not modify the bonding surface CPa of the die CP, there is no need to transfer the die CP from the first die carrier FC to the second die carrier SC. Therefore, the die carrier holding unit 421 may hold the first die carrier FC.

[0074] When the die carrier holding section 421 holds the first die carrier FC, the inversion device 39 simply inverts the first die carrier FC upside down. A plurality of dies CP can be inverted upside down all at once in advance, and the bonding surface CPa of each die CP can face downward. A mechanism for individually inverting the die CP upside down can be eliminated, and dust generation from the mechanism can be suppressed. In addition, the structures of the first die transport mechanism 423 and the second die transport mechanism 424 can be simplified. Furthermore, the number of inversions can be reduced, and throughput can be improved. Furthermore, the accuracy of the bonding position between the die CP and the substrate W can be improved.

[0075] The first die transport mechanism 423 has, for example, a first suction head 423a and a first driving unit 423b. The first suction head 423a is disposed below the die CP and suctions the bonding surface CPa of the die CP. The first suction head 423a is movable, for example, in the X-axis direction and the Z-axis direction. The first driving unit 423b moves the first suction head 423a.

[0076] It is preferable that the first suction head 423a suctions the joining surface CPa of the die CP without contact. In other words, it is preferable that the first suction head 423a suctions the joining surface CPa of the die CP while forming a gap between the first suction head 423a and the die CP. This can prevent contamination of the joining surface CPa of the die CP. The first suction head 423a is, for example, an ultrasonic type or a Bernoulli type. The ultrasonic type utilizes the squeeze effect caused by ultrasonic vibration, and the Bernoulli type utilizes the Bernoulli effect. The ultrasonic type can suppress horizontal deviation compared to the Bernoulli type.

[0077] The second die transport mechanism 424 has, for example, a second suction head 424a and a second drive unit 424b. The second suction head 424a is disposed above the die CP and suctions the back surface CPb of the die CP, which faces the opposite direction to the joining surface CPa. Since it is not a problem if the back surface CPb is dirty, the second suction head 424a comes into contact with the die CP.

[0078] The second suction head 424a is movable, for example, in the X-axis direction, the Y-axis direction, the Z-axis direction, and the θ direction. The θ direction is the circumferential direction of a vertical rotation center line. In other words, the second suction head 424a may rotate around the vertical rotation center line. The second driving unit 424b moves the second suction head 424a.

[0079] 10 and 11, the bonding device 42 may include a first moving unit 428 and a second moving unit 429. The first moving unit 428 moves the die carrier holding unit 421 in the horizontal direction. The first moving unit 428 may move the die carrier holding unit 421 in the vertical direction. The second moving unit 429 moves the substrate holding unit 422 in the horizontal direction. The second moving unit 429 may move the substrate holding unit 422 in the vertical direction.

[0080] According to this embodiment, the die carrier holding part 421 holds the second die carrier SC from above the second die carrier SC, and the substrate holding part 422 holds the substrate W from below the substrate W. Therefore, it is possible to arrange the second die carrier SC and the substrate W at different heights. Accordingly, it is possible to arrange the die carrier holding part 421 and the substrate holding part 422 at different heights. As a result, when the die carrier holding part 421 is viewed from above, it is possible to make the movement range of the die carrier holding part 421 and the movement range of the substrate holding part 422 overlap. This allows the footprint of the bonding device 42 to be reduced.

[0081] The substrate holding part 422 is movable in a horizontal first axis direction and a horizontal second axis direction perpendicular to the first axis direction. The first axis direction is, for example, the X axis direction, and the second axis direction is, for example, the Y axis direction. The substrate holding part 422 is movable in both the X axis positive direction and the X axis negative direction. In addition, the substrate holding part 422 is movable in both the Y axis positive direction and the Y axis positive direction.

[0082] The die carrier holding part 421 may be movable in both the first axial direction and the second axial direction, or may be movable only in the second axial direction out of the first axial direction and the second axial direction. In the latter case, the movement range of the die carrier holding part 421 and the movement range of the substrate holding part 422 may overlap in the first axial direction when the die carrier holding part 421 is viewed from above. In the latter case, the footprint of the bonding device 42 can be made smaller than in the former case.

[0083] 10 and 11, the bonding device 42 may include a pressing mechanism 430. The pressing mechanism 430 presses the die CP downward against the second die carrier SC held by the die carrier holding portion 421. The pressing mechanism 430 presses the die CP downward individually, and peels the die CP individually from the second die carrier SC.

[0084] The pressing mechanism 430 peels off the die CP from the second die carrier SC, for example, by supplying gas to the through-hole H1 of the conductive substrate SC1 or by inserting a pin (not shown) into the through-hole H1. The number and arrangement of the through-holes H1 are not particularly limited. The insulating film SC2 may or may not have a through-hole.

[0085] In this embodiment, the die carrier holding portion 421 holds the second die carrier SC, but may hold the first die carrier FC as described above.

[0086] (Heat treatment) The present inventors have found that heat treatment of the die-attached substrate CW at a certain target temperature may reduce the bonding strength between the die CP and the substrate W. The present inventors have also found that heat treatment of the die-attached substrate CW at a first temperature range lower than the target temperature before heat treatment at the target temperature can suppress the reduction in the bonding strength of the die-attached substrate CW. The present inventors speculate as follows about the reason why the above effect is achieved.

[0087] Before the heat treatment, the die CP and the substrate W are bonded by hydrogen bonds between OH groups. The heat treatment causes a dehydration condensation reaction of the following reaction formula (1) and an oxidation reaction of the following reaction formula (2), thereby improving the bonding strength between the die CP and the substrate W.

[0088] Si-OH+Si-OH→Si-O-Si+H2O (1) Si+H2O→SiO+H2(2)

[0089] At this time, if H2O generated by the dehydration condensation reaction of reaction formula (1) remains at the bonding interface between the die CP and the substrate W, voids (gaps) are generated at the bonding interface, which causes a decrease in the bonding strength between the die CP and the substrate W. For example, if the amount of H2O generated by the dehydration condensation reaction of reaction formula (1) (hereinafter also referred to as the "H2O generation amount") is greater than the amount of H2O consumed (absorbed) by the oxidation reaction of reaction formula (2) (hereinafter also referred to as the "H2O absorption amount"), H2O is likely to remain at the bonding interface between the die CP and the substrate W. For this reason, it is important to control the balance between the amount of H2O generated by the dehydration condensation reaction and the amount of H2O absorbed by the oxidation reaction during heat treatment.

[0090] Hereinafter, the heat treatment (step S109) in the bonding method according to the first embodiment will be described in detail.

[0091] In step S109, prior to heat-treating the die-attached substrate CW at a certain target temperature, the die-attached substrate CW is heat-treated in a first temperature range lower than the target temperature. The lower the temperature, the slower the reaction rate of the dehydration-condensation reaction. Therefore, by heat-treating the die-attached substrate CW in a first temperature range lower than the target temperature prior to heat-treating the die-attached substrate CW at the target temperature, the temperature rise rate of the die-attached substrate CW is slowed. Therefore, it is possible to prevent the amount of H2O generated by the dehydration-condensation reaction from exceeding the amount of H2O absorbed by the oxidation reaction. As a result, the amount of H2O remaining at the bonding interface between the die CP and the substrate W is prevented, and the decrease in the bonding strength between the die CP and the substrate W is prevented.

[0092] The target temperature is a temperature at which a dehydration condensation reaction occurs and a covalent bond is formed, for example, 350° C. or higher.

[0093] The heat treatment in the first temperature range may include maintaining the atmosphere in which the die-attached substrate CW is provided at a temperature range of 100° C. or more and less than 150° C. In the temperature range of 100° C. or more and less than 150° C., a dehydration reaction occurs due to evaporation of water. Therefore, by maintaining the atmosphere in which the die-attached substrate CW is provided at a temperature range of 100° C. or more and less than 150° C., a dehydration reaction due to evaporation of water can be caused. This allows H2O to be generated in advance before the atmosphere in which the die-attached substrate CW is provided reaches the target temperature. As a result, a rapid increase in the amount of H2O generated when the die-attached substrate CW is heat-treated at the target temperature can be suppressed, and the amount of H2O generated can be suppressed from exceeding the amount of H2O absorbed. The time for which the atmosphere in which the die-attached substrate CW is provided is maintained at a temperature range of 100° C. or more and less than 150° C. may be longer than the time required for the temperature of the die-attached substrate CW to reach 100° C. or more and less than 150° C., for example, 5 minutes.

[0094] The heat treatment in the first temperature range may include maintaining the atmosphere in which the die-attached substrate CW is provided at a temperature range of 300° C. or more and less than 350° C. In the temperature range of 300° C. or more and less than 350° C., a dehydration reaction occurs due to the desorption of adsorbed water. Therefore, by maintaining the atmosphere in which the die-attached substrate CW is provided at a temperature range of 300° C. or more and less than 350° C., a dehydration reaction due to the desorption of adsorbed water can be caused. This allows H2O to be generated in advance before the atmosphere in which the die-attached substrate CW is provided reaches the target temperature. As a result, a rapid increase in the amount of H2O generated when the die-attached substrate CW is heat-treated at the target temperature can be suppressed, and the amount of H2O generated can be suppressed from exceeding the amount of H2O absorbed. The time for which the atmosphere in which the die-attached substrate CW is provided is maintained at a temperature range of 300° C. or more and less than 350° C. may be longer than the time required for the temperature of the die-attached substrate CW to reach 300° C. or more and less than 350° C., for example, 5 minutes.

[0095] Next, there will be described an example of a method for heat-treating the substrate CW with a die in the annealing device 43. The annealing device 43 includes five annealing devices 43a to 43e.

[0096] First, the substrate transport arm 34 takes out the substrate CW with a die from the bonding device 42 and transports it to the annealing device 43a.

[0097] Next, the annealing device 43a heat-treats the die-attached substrate CW. The annealing device 43a has a set temperature of 50°C. Therefore, the die-attached substrate CW is heat-treated in an atmosphere of 50°C. The time for heat-treating the die-attached substrate CW in the annealing device 43a is, for example, 5 minutes. Thereafter, the substrate transport arm 34 takes out the die-attached substrate CW from the annealing device 43a and transports it to the annealing device 43b.

[0098] Next, the annealing device 43b heat-treats the die-attached substrate CW. The annealing device 43b has a set temperature of 100°C. Therefore, the die-attached substrate CW is heat-treated in an atmosphere of 100°C. The time for heat-treating the die-attached substrate CW in the annealing device 43b is, for example, 5 minutes. Thereafter, the substrate transport arm 34 takes out the die-attached substrate CW from the annealing device 43b and transports it to the annealing device 43c.

[0099] Next, the annealing device 43c heat-treats the die-attached substrate CW. The annealing device 43c has a set temperature of 150°C. Therefore, the die-attached substrate CW is heat-treated in an atmosphere of 150°C. The time for heat-treating the die-attached substrate CW in the annealing device 43c is, for example, 5 minutes. Thereafter, the substrate transport arm 34 takes out the die-attached substrate CW from the annealing device 43c and transports it to the annealing device 43d.

[0100] Next, the annealing device 43d heat-treats the die-attached substrate CW. The annealing device 43d has a set temperature of 200°C. Therefore, the die-attached substrate CW is heat-treated in an atmosphere of 200°C. The time for heat-treating the die-attached substrate CW in the annealing device 43d is, for example, 5 minutes. Thereafter, the substrate transport arm 34 takes out the die-attached substrate CW from the annealing device 43d and transports it to the annealing device 43e.

[0101] Next, the annealing device 43e heat-treats the die-attached substrate CW. The set temperature of the annealing device 43e is 350°C (target temperature). Therefore, the die-attached substrate CW is heat-treated in an atmosphere of 350°C. This improves the bonding strength between the die CP and the substrate W. The time for heat-treating the die-attached substrate CW in the annealing device 43e is, for example, 60 minutes. Thereafter, the substrate transport arm 34 takes out the die-attached substrate CW from the annealing device 43e and transports it to the transition device 25. Finally, the substrate transport arm 24 takes out the die-attached substrate CW from the transition device 25 and stores it in the cassette C6. The die-attached substrate CW is transported out of the bonding system 1 while being stored in the cassette C6.

[0102] As described above, according to the first embodiment, the die-attached substrate CW is moved through the five annealing devices 43a-43e in this order, and the temperature of the atmosphere in which the die-attached substrate CW is provided is increased stepwise as shown in FIG. 12. In this case, the temperature rise rate of the die-attached substrate CW becomes gentle during the heat treatment in step S109. This makes it possible to prevent the amount of H2O generated by the dehydration condensation reaction from exceeding the amount of H2O absorbed by the oxidation reaction. As a result, the remaining of H2O at the bonding interface between the die CP and the substrate W is suppressed, and the decrease in the bonding strength between the die CP and the substrate W is suppressed. In addition, the set temperature of each of the annealing devices 43a-43e is not changed during the heat treatment. Therefore, the time required for raising and lowering the temperature of each of the annealing devices 43a-43e is not required. In addition, the power consumption of each of the annealing devices 43a-43e can be reduced.

[0103] The amount of H2O generated during heat treatment varies depending on the number of die CPs, the size of the die CPs, the thickness of the die CPs, the arrangement pitch of the die CPs, etc. Therefore, it is preferable to determine the temperature rise conditions during heat treatment depending on the number of die CPs, the size of the die CPs, the thickness of the die CPs, the arrangement pitch of the die CPs, etc. In this case, the time required for heat treatment can be shortened while suppressing the residual H2O at the bonding interface between the die CPs and the substrate W. The temperature rise conditions include, for example, the time required for heat treatment of the die-attached substrate CW in each of the annealing devices 43a to 43e. The temperature rise conditions may include the set temperature of each of the annealing devices 43a to 43e.

[0104] In the first embodiment, the case where the die-attached substrate CW is moved through the five annealing devices 43a to 43e in this order has been described, but the present invention is not limited to this. For example, the temperature setting of one of the annealing devices 43 may be changed to increase the temperature of the atmosphere in which the die-attached substrate CW is provided in a stepwise manner.

[0105] In the first embodiment, the temperature of the atmosphere in which the die-attached substrate CW is provided is increased stepwise, but the present invention is not limited to this. For example, as shown in FIG. 13, the temperature of the atmosphere in which the die-attached substrate CW is provided may be increased continuously from room temperature to a target temperature. In this case, it is preferable to increase the set temperature from room temperature to 350° C. (target temperature) at a rate of temperature increase of 10° C. / min or less. This makes it easy to prevent the amount of H2O generated from exceeding the amount of H2O absorbed, regardless of the type of film to be bonded, and to prevent H2O from remaining at the bonding interface between the die CP and the substrate W.

[0106] In the first embodiment, the bonding system 1 includes the annealing device 43. However, the present invention is not limited to this. For example, an annealing device may be provided separately from the bonding system 1.

[0107] Second Embodiment (system) A system according to the second embodiment will be described with reference to Fig. 14 to Fig. 20. The system includes a bonding system BN1 and an annealing system AN1.

[0108] The bonding system BN1 bonds a first semiconductor substrate and a second semiconductor substrate to produce a laminated substrate. As shown in Fig. 15, the substrate placed on the lower side during bonding is called the lower wafer W1, and the substrate placed on the upper side during bonding is called the upper wafer W2. The lower wafer W1 corresponds to the first semiconductor substrate and the upper wafer W2 corresponds to the second semiconductor substrate, but the combination may be reversed, and the lower wafer W1 may correspond to the second semiconductor substrate and the upper wafer W2 may correspond to the first semiconductor substrate.

[0109] The lower wafer W1 and the upper wafer W2 are bonded to obtain a laminated wafer T. Of the surfaces of the lower wafer W1, the surface that is bonded to the upper wafer W2 is referred to as a "bonding surface W1j," and the surface opposite the bonding surface W1j is referred to as a "non-bonding surface W1n." Of the surfaces of the upper wafer W2, the surface that is bonded to the lower wafer W1 is referred to as a "bonding surface W2j," and the surface opposite the bonding surface W2j is referred to as a "non-bonding surface W2n."

[0110] The lower wafer W1 has a semiconductor substrate such as a silicon wafer and a film formed on the semiconductor substrate. A glass substrate may be used instead of the semiconductor substrate. The film has, for example, a device layer and a bonding layer. The device layer includes a plurality of electronic circuits. The bonding layer is formed on the device layer. The bonding layer is, for example, a silicon oxide film, a silicon nitride film, or a silicon carbonitride film.

[0111] The upper wafer W2 has a semiconductor substrate such as a silicon wafer and a film formed on the semiconductor substrate. A glass substrate may be used instead of the semiconductor substrate. The film has, for example, a device layer and a bonding layer. The device layer includes a plurality of electronic circuits. The bonding layer is formed on the device layer. The bonding layer is, for example, a silicon oxide film, a silicon nitride film, or a silicon carbonitride film.

[0112] It is noted that one of the lower wafer W1 and the upper wafer W2 does not necessarily have to have a device layer.

[0113] 14, the bonding system BN1 includes a loading / unloading station BN2 and a processing station BN3. The loading / unloading station BN2 and the processing station BN3 are arranged in the positive direction of the X-axis in the order of the loading / unloading station BN2 and the processing station BN3. The loading / unloading station BN2 and the processing station BN3 are integrally connected.

[0114] The carry-in / out station BN2 includes a mounting table BN10 and a transfer area BN20. The mounting table BN10 includes a plurality of mounting plates BN11. Each mounting plate BN11 is mounted with a cassette C21, C22, or C23 that accommodates a plurality of substrates (e.g., 25 substrates) in a horizontal state. The cassette C21 is a cassette that accommodates a lower wafer W1, the cassette C22 is a cassette that accommodates an upper wafer W2, and the cassette C23 is a cassette that accommodates a laminated wafer T. In the cassettes C21 and C22, the lower wafer W1 and the upper wafer W2 are accommodated with the same orientation with their bonding surfaces W1j and W2j facing upwards, respectively.

[0115] The transfer area BN20 is disposed adjacent to the mounting table BN10 on the positive side of the X-axis. The transfer area BN20 is provided with a transfer path BN21 extending in the Y-axis direction and a transfer device BN22 movable along the transfer path BN21. The transfer device BN22 has a transfer arm that holds and transfers the lower wafer W1, the upper wafer W2, or the overlapped wafer T. The transfer arm is movable in the horizontal and vertical directions and is rotatable around a vertical axis. There may be more than one transfer arm. The transfer arm transfers the upper wafer W2, the lower wafer W1, or the overlapped wafer T to a predetermined device adjacent to the transfer area BN20.

[0116] The number of cassettes C21 to C23 placed on the placement table BN10 is not limited to that shown in the figure. In addition to the cassettes C21, C22, and C23, a cassette for recovering defective substrates may be placed on the placement table BN10.

[0117] In the processing station BN3, for example, three processing blocks G11, G12, and G13 are provided. For example, a first processing block G11 is provided on the rear side (positive Y-axis side in FIG. 14) of the processing station BN3, and a second processing block G12 is provided on the front side (negative Y-axis side in FIG. 14) of the processing station BN3. A third processing block G13 is provided on the loading / unloading station BN2 side (negative X-axis side in FIG. 14) of the processing station BN3.

[0118] A transfer region BN60 is formed in an area surrounded by the first processing block G11 to the third processing block G13. A transfer device BN61 is disposed in the transfer region BN60. The transfer device BN61 has a transfer arm that holds and transfers the lower wafer W1, the upper wafer W2, or the overlapped wafer T. The transfer arm is movable in the horizontal and vertical directions and can rotate around a vertical axis. There may be more than one transfer arm. The transfer arm transfers the lower wafer W1, the upper wafer W2, or the overlapped wafer T to a predetermined device adjacent to the transfer region BN60.

[0119] In the first processing block G11, for example, an activation device BN33 and a hydrophilization device BN34 are arranged. The activation device BN33 modifies the bonding surface W1j of the lower wafer W1 or the bonding surface W2j of the upper wafer W2 with plasma. The hydrophilization device BN34 hydrophilizes the modified bonding surface W1j of the lower wafer W1 or the modified bonding surface W2j of the upper wafer W2. The positions of the activation device BN33 and the hydrophilization device BN34 are not limited to those shown in the figure. The number of the activation device BN33 and the hydrophilization device BN34 may be more than one.

[0120] The activation device BN33, for example, breaks the SiO2 bonds on the bonding surfaces W1j and W2j to form dangling bonds of Si, enabling subsequent hydrophilization. In the activation device BN33, for example, oxygen gas, which is a processing gas, is excited to plasma and ionized under a reduced pressure atmosphere. Then, the bonding surfaces W1j and W2j are irradiated with oxygen ions, so that the bonding surfaces W1j and W2j are plasma-processed and modified. The processing gas is not limited to oxygen gas, and may be, for example, nitrogen gas or the like.

[0121] The hydrophilization apparatus BN34, for example, provides OH groups to the bonding surfaces W1j and W2j. The hydrophilization apparatus BN34 supplies pure water onto the lower wafer W1 or the upper wafer W2 while rotating the lower wafer W1 or the upper wafer W2 held by, for example, a spin chuck. The pure water diffuses over the bonding surfaces W1j and W2j, providing OH groups to dangling bonds of Si, and hydrophilizing the bonding surfaces W1j and W2j. The hydrophilization apparatus BN34 also serves to clean the bonding surfaces W1j and W2j.

[0122] In the second processing block G12, for example, a bonding apparatus BN41 is disposed. The bonding apparatus BN41 turns the upper wafer W2 upside down so that the bonding surface W2j of the upper wafer W2 faces downward. Thereafter, the bonding apparatus BN41 bonds the hydrophilized lower wafer W1 and the upper wafer W2 to produce a laminated wafer T. In this embodiment, a device for turning the upper wafer W2 upside down is provided as a part of the bonding apparatus BN41, but may be provided separately from the bonding apparatus BN41.

[0123] In the third processing block G13, for example, a transition apparatus BN51 is disposed. The transition apparatus BN51 temporarily stores the lower wafer W1, the upper wafer W2, or the overlapped wafer T. The number of the transition apparatus BN51 may be more than one.

[0124] The bonding system BN1 includes a control device BN90. The control device BN90 is, for example, a computer, and includes a calculation unit BN91 such as a CPU, and a storage unit BN92 such as a memory. The storage unit BN92 stores programs that control various processes executed in the bonding system BN1. The control device BN90 controls the operation of the bonding system BN1 by having the calculation unit BN91 execute the programs stored in the storage unit BN92.

[0125] The annealing system AN1 includes a loading / unloading station AN2 and a processing station AN3. The loading / unloading station AN2 and the processing station AN3 are arranged in the positive direction of the X-axis in the order of the loading / unloading station AN2 and the processing station AN3. The loading / unloading station AN2 and the processing station AN3 are integrally connected.

[0126] The loading / unloading station AN2 includes a mounting table AN10 and a transfer area AN20. The mounting table AN10 includes a plurality of mounting plates AN11. Each mounting plate AN11 is mounted with a cassette C23 that stores a plurality of substrates (e.g., 25 substrates) in a horizontal state. The cassette C23 is a cassette that stores a laminated wafer T.

[0127] The transfer area AN20 is disposed adjacent to the mounting table AN10 on the positive side of the X-axis. The transfer area AN20 is provided with a transfer path AN21 extending in the Y-axis direction, and a transfer device AN22 movable along the transfer path AN21. The transfer device AN22 has a transfer arm that holds and transfers the overlapped wafer T. The transfer arm is movable in the horizontal and vertical directions, and is rotatable around a vertical axis. There may be more than one transfer arm. The transfer arm transfers the overlapped wafer T to a predetermined device adjacent to the transfer area AN20.

[0128] The number of cassettes C23 placed on the mounting stand AN10 is not limited to that shown in the figure. In addition to the cassettes C23, a cassette for recovering defective substrates may be placed on the mounting stand AN10.

[0129] In the processing station AN3, for example, three processing blocks G21, G22, and G23 are provided. For example, a first processing block G21 is provided on the rear side of the processing station AN3 (the Y-axis positive side in FIG. 14), and a second processing block G22 is provided on the front side of the processing station AN3 (the Y-axis negative side in FIG. 14). In addition, a third processing block G23 is provided on the loading / unloading station AN2 side of the processing station AN3 (the X-axis negative side in FIG. 14).

[0130] A transfer area AN60 is formed in an area surrounded by the first processing block G21 to the third processing block G23. A transfer device AN61 is disposed in the transfer area AN60. The transfer device AN61 has a transfer arm that holds and transfers the overlapped wafer T. The transfer arm is movable in the horizontal and vertical directions and is rotatable about a vertical axis. There may be more than one transfer arm. The transfer arm transfers the overlapped wafer T to a predetermined device adjacent to the transfer area AN60.

[0131] In the first processing block G21, for example, an annealing apparatus AN43 and an annealing apparatus AN44 are arranged. The annealing apparatus AN43 heat-treats the polymerized wafer T. Before the heat treatment, the lower wafer W1 and the upper wafer W2 are bonded by hydrogen bonds between OH groups. The heat treatment causes a dehydration condensation reaction, which generates covalent bonds, improving the bonding strength between the lower wafer W1 and the upper wafer W2. The annealing apparatus AN43 is stacked in a plurality of units in the Z-axis direction, for example. The plurality of annealing apparatuses AN43 are configured to heat-treat the polymerized wafer T at different set temperatures. The plurality of annealing apparatuses AN43 include an annealing apparatus whose set temperature is a target temperature and an annealing apparatus whose set temperature is in a first temperature range lower than the target temperature. The target temperature is a temperature at which a dehydration condensation reaction occurs and covalent bonds are formed. The target temperature is, for example, 350° C. or higher. In this embodiment, the plurality of annealing apparatuses AN43 includes five annealing apparatuses AN43a to AN43e. The annealing apparatuses AN43a, AN43b, AN43c, AN43d, and AN43e have set temperatures of 50°C, 100°C, 150°C, 200°C, and 350°C (target temperatures), respectively. The number of annealing apparatuses AN43 is not limited to that shown in the figure. The annealing apparatus AN44 may have the same configuration as the annealing apparatus AN43. The annealing apparatus AN44 includes five annealing apparatuses AN44a to AN44e. When the annealing apparatus AN44 is provided, a plurality of overlapped wafers T can be heat-treated simultaneously. The annealing apparatus AN44 may not be provided.

[0132] In the second processing block G22, for example, an annealing apparatus AN45 and an annealing apparatus AN46 are arranged. The annealing apparatus AN45 and the annealing apparatus AN46 may each have the same configuration as the annealing apparatus AN43. The annealing apparatus AN45 includes five annealing apparatuses AN45a to AN45e. The annealing apparatus AN46 includes five annealing apparatuses AN46a to AN46e. When the annealing apparatus AN45 and the annealing apparatus AN46 are present, a plurality of laminated wafers T can be heat-treated simultaneously. The annealing apparatus AN45 and the annealing apparatus AN46 may not be present.

[0133] In the third processing block G23, for example, a transition apparatus AN51 is disposed. The transition apparatus AN51 temporarily stores the overlapped wafer T. The number of the transition apparatus AN51 may be more than one.

[0134] The annealing system AN1 includes a control device AN90. The control device AN90 is, for example, a computer, and includes an arithmetic unit AN91 such as a CPU, and a storage unit AN92 such as a memory. The storage unit AN92 stores programs that control various processes executed in the annealing system AN1. The control device AN90 controls the operation of the annealing system AN1 by having the arithmetic unit AN91 execute the programs stored in the storage unit AN92.

[0135] (Joining method) A bonding method according to the second embodiment will be described with reference to Fig. 16. The process in Fig. 16 is performed under the control of control devices BN90 and AN90.

[0136] First, the cassette C21 accommodating a plurality of lower wafers W1, the cassette C22 accommodating a plurality of upper wafers W2, and the empty cassette C23 are placed on the placement table BN10 of the carry-in / out station BN2.

[0137] Next, the transfer device BN22 takes out the lower wafer W1 in the cassette C21 and transfers it to the transition device BN51. Thereafter, the transfer device BN61 takes out the lower wafer W1 from the transition device BN51 and transfers it to the activation device BN33.

[0138] Next, the activation device BN33 modifies the bonding surface W1j of the lower wafer W1 (step S201). The modification of the bonding surface W1j is performed with the bonding surface W1j facing upward. Thereafter, the transfer device BN61 takes out the lower wafer W1 from the activation device BN33 and transfers it to the hydrophilization device BN34.

[0139] Next, the hydrophilizing apparatus BN34 hydrophilizes the bonding surface W1j of the lower wafer W1 (step S202). The hydrophilizing of the bonding surface W1j is performed with the bonding surface W1j facing upward. Thereafter, the transfer apparatus BN61 takes out the lower wafer W1 from the hydrophilizing apparatus BN34 and transfers it to the bonding apparatus BN41.

[0140] In parallel with the above-mentioned processing for the lower wafer W1, the following processing for the upper wafer W2 is performed. First, the transfer device BN22 takes out the upper wafer W2 in the cassette C22 and transfers it to the transition device BN51. Then, the transfer device BN61 takes out the upper wafer W2 from the transition device BN51 and transfers it to the activation device BN33.

[0141] Next, the activation device BN33 modifies the bonding surface W2j of the upper wafer W2 (step S203). The modification of the bonding surface W2j is performed with the bonding surface W2j facing upward. Thereafter, the transfer device BN61 takes out the upper wafer W2 from the activation device BN33 and transfers it to the hydrophilization device BN34.

[0142] Next, the hydrophilizing apparatus BN34 hydrophilizes the bonding surface W2j of the upper wafer W2 (step S204). The hydrophilizing of the bonding surface W2j is performed with the bonding surface W2j facing upward. Thereafter, the transfer apparatus BN61 takes out the upper wafer W2 from the hydrophilizing apparatus BN34 and transfers it to the bonding apparatus BN41.

[0143] Next, the bonding apparatus BN41 turns the upper wafer W2 upside down so that the bonding surface W2j of the upper wafer W2 faces downward. After that, the bonding apparatus BN41 bonds the lower wafer W1 and the upper wafer W2 to manufacture the overlapped wafer T (step S205). After that, the transfer apparatus BN61 takes out the overlapped wafer T from the bonding apparatus BN41 and transfers it to the transition apparatus BN51.

[0144] Next, the transfer device BN22 takes out the overlapped wafer T from the transition device BN51 and transfers it to the cassette C23 on the mounting table BN10. Next, a transfer device (not shown) transfers the cassette C23 on the mounting table BN10 to the mounting table AN10 of the annealing system AN1.

[0145] Next, the transfer device AN22 takes out the overlapped wafer T in the cassette C23 and transfers it to the transition device AN51. Thereafter, the transfer device AN61 takes out the overlapped wafer T from the transition device AN51 and transfers it to the annealing device AN43.

[0146] Next, the annealing device AN43 heat-treats the overlapped wafer T (step S206). This improves the bonding strength between the lower wafer W1 and the upper wafer W2. Details of the heat treatment will be described later. Thereafter, the transfer device AN61 takes out the overlapped wafer T from the annealing device AN43 and transfers it to the transition device AN51.

[0147] Next, the transfer device AN22 takes out the overlapped wafer T from the transition device AN51 and transfers it to the cassette C23 on the mounting table AN10, thereby completing a series of processes.

[0148] (Joining equipment) An example of the joining device BN41 will be described with reference to Fig. 17. The joining device BN41 includes a lower holding unit 110, an upper holding unit 120, a lower imaging unit 130, an upper imaging unit 150, a moving unit 170, and a control unit 200.

[0149] The lower holding part 110 holds the lower wafer W1 from below with the bonding surface W1j of the lower wafer W1 facing upward, and the upper holding part 120 holds the upper wafer W2 from above with the bonding surface W2j of the upper wafer W2 facing downward.

[0150] The lower imaging unit 130 is provided in the lower holding unit 110 and images the upper wafer W2 held by the upper holding unit 120. The upper imaging unit 150 is provided in the upper holding unit 120 and images the lower wafer W1 held by the lower holding unit 110.

[0151] The moving unit 170 moves the lower holding unit 110 and the upper holding unit 120 relatively in the horizontal and vertical directions. In this embodiment, the moving unit 170 moves the lower holding unit 110, but may move the upper holding unit 120. The moving unit 170 may rotate the lower holding unit 110 or the upper holding unit 120 around a vertical axis.

[0152] The control unit 200 controls the operation of the bonding device BN41. The control unit 200 is, for example, a computer, and is configured similarly to the control device BN90. The control unit 200 may be a part of the control device BN90.

[0153] The lower holding part 110 is partitioned into a plurality of (for example, two) regions 110a and 110b. These regions 110a and 110b are provided in this order from the center toward the periphery of the lower holding part 110. The region 110a has a circular shape in a plan view, and the region 110b has an annular shape in a plan view.

[0154] Suction pipes 111a and 111b are provided independently for each of the regions 110a and 110b. Different vacuum pumps 112a and 112b are connected to the suction pipes 111a and 111b, respectively. The lower holding part 110 can vacuum-suck the lower wafer W1 for each of the regions 110a and 110b.

[0155] A plurality of holding pins 115 that can be raised and lowered in the vertical direction are provided on the lower holding part 110. The lower wafer W1 is placed on the upper ends of the plurality of holding pins 115. The lower wafer W1 may be vacuum-sucked to the upper ends of the plurality of holding pins 115.

[0156] The multiple holding pins 115 rise and protrude from the holding surface of the lower holding part 110. In this state, the multiple holding pins 115 receive the lower wafer W1 from the transfer device BN61. Thereafter, the multiple holding pins 115 descend and the lower wafer W1 is brought into contact with the holding surface of the lower holding part 110. Next, the lower holding part 110 horizontally vacuum-adsorbs the lower wafer W1 in each of the regions 110a and 110b by operating the vacuum pumps 112a and 112b.

[0157] Upper holding part 120 is partitioned into multiple (e.g., three) regions 120a, 120b, and 120c. These regions 120a, 120b, and 120c are provided in this order from the center toward the periphery of upper holding part 120. Region 120a has a circular shape in a plan view, and regions 120b and 120c have annular shapes in a plan view.

[0158] Suction pipes 121a, 121b, and 121c are provided independently for the respective regions 120a, 120b, and 120c. Different vacuum pumps 122a, 122b, and 122c are connected to the respective suction pipes 121a, 121b, and 121c. The upper holding part 120 can vacuum-suck the upper wafer W2 for each of the regions 120a, 120b, and 120c.

[0159] The upper holding part 120 is provided with a plurality of holding pins 125 that can be raised and lowered in the vertical direction. The plurality of holding pins 125 are connected to a vacuum pump 126, and vacuum-suck the upper wafer W2 by operation of the vacuum pump 126. The upper wafer W2 is vacuum-sucked to the lower ends of the plurality of holding pins 125. Instead of the plurality of holding pins 125, ring-shaped suction pads may be used.

[0160] The multiple holding pins 125 move downward to protrude from the holding surface of the upper holding part 120. In this state, the multiple holding pins 125 vacuum-suck the upper wafer W2 and receive it from the transfer device BN61. Thereafter, the multiple holding pins 125 move upward, and the upper wafer W2 is brought into contact with the holding surface of the upper holding part 120. Next, the upper holding part 120 horizontally vacuum-sucks the upper wafer W2 in each of the regions 120a, 120b, and 120c by operating the vacuum pumps 122a, 122b, and 122c.

[0161] Further, a through hole 123 that passes vertically through the upper holding part 120 is formed in the center of the upper holding part 120. A pushing part 190, which will be described later, is inserted into the through hole 123. The pushing part 190 pushes down the center of the upper wafer W2, which is disposed at a distance from the lower wafer W1, and brings it into contact with the lower wafer W1.

[0162] The pushing part 190 has a pushing pin 191 and an outer cylinder 192 which serves as an elevation guide for the pushing pin 191. The pushing pin 191 is inserted into the through hole 123 by, for example, a drive part (not shown) having a built-in motor, protrudes from the holding surface of the upper holding part 120, and pushes down the center of the upper wafer W2.

[0163] Next, an example of the operation of the bonding apparatus BN41 will be described with reference to Figs. 18 to 20. First, the transfer apparatus BN61 loads the lower wafer W1 and the upper wafer W2 into the bonding apparatus BN41. The lower holding unit 110 holds the lower wafer W1 from below with the bonding surface W1j of the lower wafer W1 facing upward. The upper holding unit 120 holds the upper wafer W2 from above with the bonding surface W2j of the upper wafer W2 facing downward.

[0164] Next, the moving unit 170 moves the lower holding unit 110 and the upper holding unit 120 relatively to align the lower wafer W1 and the upper wafer W2. For the alignment, the lower imaging unit 130 and the upper imaging unit 150 are used as shown in Fig. 17. The upper imaging unit 150 is fixed to the upper holding unit 120, and images the bonding surface W1j of the lower wafer W1 held by the lower holding unit 110. On the other hand, the lower imaging unit 130 is fixed to the lower holding unit 110, and images the bonding surface W2j of the upper wafer W2 held by the upper holding unit 120.

[0165] 18, the operation of the vacuum pump 122a is stopped, and the vacuum suction of the upper wafer W2 in the region 120a is released. After that, the pushing pin 191 of the pushing part 190 descends, pushing down the center of the upper wafer W2 and bringing it into contact with the lower wafer W1. As a result, the centers of the lower wafer W1 and the upper wafer W2 are bonded together.

[0166] Since the bonding surface W1j of the lower wafer W1 and the bonding surface W2j of the upper wafer W2 have been modified, van der Waals forces (intermolecular forces) are generated between the bonding surfaces W1j and W2j, and the bonding surfaces W1j and W2j are bonded to each other. Furthermore, since the bonding surfaces W1j and W2j have been hydrophilized, hydrophilic groups (e.g., OH groups) form hydrogen bonds, and the bonding surfaces W1j and W2j are firmly bonded to each other.

[0167] 19, the operation of the vacuum pump 122b is stopped, and the vacuum suction of the upper wafer W2 in the region 120b is released. Then, the operation of the vacuum pump 122c is stopped, and the vacuum suction of the upper wafer W2 in the region 120c is released, as shown in FIG.

[0168] In this way, the vacuum suction of the upper wafer W2 is released stepwise from the center to the periphery of the upper wafer W2, and the upper wafer W2 drops stepwise onto the lower wafer W1 and abuts thereon. Then, the bonding of the lower wafer W1 and the upper wafer W2 progresses sequentially from the center to the periphery. As a result, the bonding surface W1j of the upper wafer W2 and the bonding surface W2j of the lower wafer W1 abut on each other over their entire surfaces, the lower wafer W1 and the upper wafer W2 are bonded together, and the laminated wafer T is obtained. After that, the pushing pin 191 is raised to its original position.

[0169] Next, the moving unit 170 lowers the lower holding unit 110 to widen the vertical distance between the lower holding unit 110 and the upper holding unit 120. Thereafter, the transfer device BN61 transfers the overlapped wafer T to the bonding device BN41. Specifically, first, the lower holding unit 110 releases the hold of the overlapped wafer T. Next, the multiple holding pins 115 rise and deliver the overlapped wafer T to the transfer device BN61. Then, the multiple holding pins 115 descend to their original positions.

[0170] (Heat treatment) The heat treatment (step S206) in the bonding method according to the second embodiment will be described in detail.

[0171] In step S206, prior to heat-treating the polymerized wafer T at a certain target temperature, the polymerized wafer T is heat-treated in a first temperature range lower than the target temperature. The lower the temperature, the slower the reaction rate of the dehydration-condensation reaction. Therefore, by heat-treating the polymerized wafer T in the first temperature range lower than the target temperature prior to heat-treating the polymerized wafer T at the target temperature, the temperature rise rate of the polymerized wafer T becomes gentle. Therefore, it is possible to prevent the amount of H2O generated by the dehydration-condensation reaction from exceeding the amount of H2O absorbed by the oxidation reaction. As a result, the amount of H2O remaining at the bonding interface between the lower wafer W1 and the upper wafer W2 is prevented, and the decrease in the bonding strength between the lower wafer W1 and the upper wafer W2 is prevented.

[0172] The target temperature is a temperature at which a dehydration condensation reaction occurs and a covalent bond is formed, for example, 350° C. or higher.

[0173] The heat treatment in the first temperature range may include maintaining the atmosphere in which the polymerized wafer T is provided at a temperature range of 100° C. or more and less than 150° C. In the temperature range of 100° C. or more and less than 150° C., a dehydration reaction occurs due to evaporation of water. Therefore, by maintaining the atmosphere in which the polymerized wafer T is provided at a temperature range of 100° C. or more and less than 150° C., a dehydration reaction due to evaporation of water can be caused. This allows H2O to be generated in advance before the atmosphere in which the polymerized wafer T is provided reaches the target temperature. As a result, a sudden increase in the amount of H2O generated when the polymerized wafer T is heat treated at the target temperature can be suppressed, and the amount of H2O generated can be suppressed from exceeding the amount of H2O absorbed. The time for which the atmosphere in which the polymerized wafer T is provided is maintained at a temperature range of 100° C. or more and less than 150° C. may be longer than the time required for the temperature of the polymerized wafer T to reach 100° C. or more and less than 150° C., for example, 5 minutes.

[0174] The heat treatment in the first temperature range may include maintaining the atmosphere in which the polymerized wafer T is provided in a temperature range of 300° C. or more and less than 350° C. In the temperature range of 300° C. or more and less than 350° C., a dehydration reaction occurs due to the desorption of adsorbed water. Therefore, by maintaining the atmosphere in which the polymerized wafer T is provided in a temperature range of 300° C. or more and less than 350° C., a dehydration reaction due to the desorption of adsorbed water can be caused. This allows H2O to be generated in advance before the atmosphere in which the polymerized wafer T is provided reaches the target temperature. As a result, a sudden increase in the amount of H2O generated when the polymerized wafer T is heat treated at the target temperature can be suppressed, and the amount of H2O generated can be suppressed from exceeding the amount of H2O absorbed. The time for which the atmosphere in which the polymerized wafer T is provided is maintained in a temperature range of 300° C. or more and less than 350° C. may be longer than the time required for the temperature of the polymerized wafer T to reach 300° C. or more and less than 350° C., for example, 5 minutes.

[0175] Next, an example of a method for heat-treating the overlapped wafer T in the annealing apparatus AN43 will be described. The annealing apparatus AN43 includes five annealing apparatuses AN43a to AN43e.

[0176] First, the annealing apparatus AN43a heat-treats the overlapped wafer T. The annealing apparatus AN43a has a set temperature of 50° C. Therefore, the overlapped wafer T is heat-treated in an atmosphere of 50° C. The time for heat-treating the overlapped wafer T in the annealing apparatus AN43a is, for example, 5 minutes. Thereafter, the transfer apparatus AN61 takes out the overlapped wafer T from the annealing apparatus AN43a and transfers it to the annealing apparatus AN43b.

[0177] Next, the annealing apparatus AN43b heat-treats the overlapped wafer T. The annealing apparatus AN43b has a set temperature of 100° C. Therefore, the overlapped wafer T is heat-treated in an atmosphere of 100° C. The time for heat-treating the overlapped wafer T in the annealing apparatus AN43b is, for example, 5 minutes. Thereafter, the transfer apparatus AN61 takes out the overlapped wafer T from the annealing apparatus AN43b and transfers it to the annealing apparatus AN43c.

[0178] Next, the annealing apparatus AN43c heat-treats the overlapped wafer T. The annealing apparatus AN43c has a set temperature of 150° C. Therefore, the overlapped wafer T is heat-treated in an atmosphere of 150° C. The time for heat-treating the overlapped wafer T in the annealing apparatus AN43c is, for example, 5 minutes. Thereafter, the transfer apparatus AN61 takes out the overlapped wafer T from the annealing apparatus AN43c and transfers it to the annealing apparatus AN43d.

[0179] Next, the annealing apparatus AN43d heat-treats the overlapped wafer T. The set temperature of the annealing apparatus AN43d is 200° C. Therefore, the overlapped wafer T is heat-treated in an atmosphere at 200° C. The time for heat-treating the overlapped wafer T in the annealing apparatus AN43d is, for example, 5 minutes. Thereafter, the transfer apparatus AN61 takes out the overlapped wafer T from the annealing apparatus AN43d and transfers it to the annealing apparatus AN43e.

[0180] Next, the annealing device AN43e heat-treats the overlapped wafer T. The set temperature of the annealing device AN43e is 350°C (target temperature). Therefore, the overlapped wafer T is heat-treated in an atmosphere of 350°C. This improves the bonding strength between the lower wafer W1 and the upper wafer W2. The time for heat-treating the overlapped wafer T in the annealing device AN43e is, for example, 60 minutes. Thereafter, the transfer device AN61 takes out the overlapped wafer T from the annealing device AN43e and transfers it to the transition device AN51. Finally, the transfer device AN22 takes out the overlapped wafer T from the transition device AN51 and stores it in the cassette C23. The overlapped wafer T is transferred out of the annealing system AN1 while being stored in the cassette C23.

[0181] As described above, according to the second embodiment, the temperature of the atmosphere in which the overlapped wafer T is placed is increased stepwise as shown in FIG. 12 by moving the overlapped wafer T through the five annealing devices AN43a to AN43e in this order. In this case, the temperature increase rate of the overlapped wafer T becomes gentle during the heat treatment in step S206. Therefore, it is possible to prevent the amount of H2O generated by the dehydration condensation reaction from exceeding the amount of H2O absorbed by the oxidation reaction. As a result, the remaining of H2O at the bonding interface between the lower wafer W1 and the upper wafer W2 is prevented, and the decrease in the bonding strength between the lower wafer W1 and the upper wafer W2 is prevented. In addition, the set temperature of each of the annealing devices AN43a to AN43e is not changed during the heat treatment. Therefore, the time required for increasing and decreasing the temperature of each of the annealing devices AN43a to AN43e is not required. In addition, the power consumption of each of the annealing devices AN43a to AN43e can be reduced.

[0182] The amount of H2O generated during the heat treatment varies depending on the type of films to be bonded, the activation conditions of the bonding surfaces W1j and W2j, the hydrophilization conditions of the bonding surfaces W1j and W2j, the waiting time from the end of the bonding in step S205 to the start of the heat treatment in step S206, and the like. Therefore, it is preferable to determine the heating conditions during the heat treatment depending on the type of films to be bonded, the activation conditions of the bonding surfaces W1j and W2j, the hydrophilization conditions of the bonding surfaces W1j and W2j, the waiting time, and the like. In this case, the time required for the heat treatment can be shortened while suppressing the residual of H2O at the bonding interface between the lower wafer W1 and the upper wafer W2. The heating conditions include, for example, the time for heat-treating the laminated wafer T in each of the annealing devices AN43a to AN43e. The heating conditions may include the set temperature of each of the annealing devices AN43a to AN43e.

[0183] In the second embodiment, the overlapped wafer T is moved through the five annealing apparatuses AN43a to AN43e in this order, but the present invention is not limited to this. For example, the temperature of the atmosphere in which the overlapped wafer T is placed may be increased in a stepwise manner by changing the set temperature of one of the annealing apparatuses AN43.

[0184] In the second embodiment, the temperature of the atmosphere in which the laminated wafer T is provided is increased stepwise, but the present invention is not limited thereto. For example, as shown in FIG. 13, the temperature of the atmosphere in which the laminated wafer T is provided may be increased continuously from room temperature to a target temperature. In this case, it is preferable to increase the set temperature from room temperature to the target temperature at a rate of temperature increase of 10° C. / min or less. This makes it easy to prevent the amount of H2O generated from exceeding the amount of H2O absorbed, regardless of the type of films to be bonded, and to prevent H2O from remaining at the bonding interface between the lower wafer W1 and the upper wafer W2.

[0185] In the second embodiment, the annealing system AN1 is provided separately from the bonding system BN1, but the present invention is not limited to this. For example, the bonding system BN1 may include the annealing device AN43.

[0186] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0187] CP Die W substrate CW Die-on-Board W1 Lower wafer W2 Upper wafer T Polymerized Wafer

Claims

1. Providing a first semiconductor substrate having a first surface and a second semiconductor substrate having a second surface; making the first surface of the first semiconductor substrate and the second surface of the second semiconductor substrate hydrophilic; After the hydrophilization, bonding the first surface of the first semiconductor substrate and the second surface of the second semiconductor substrate; After the bonding, heat treating the first semiconductor substrate and the second semiconductor substrate to increase a bonding strength between the first semiconductor substrate and the second semiconductor substrate; having Increasing the bonding strength includes heat treating the first semiconductor substrate and the second semiconductor substrate in a first temperature range; after the heat treatment in the first temperature range, heat treating the first semiconductor substrate and the second semiconductor substrate at a target temperature; Including, The first temperature range is a temperature range lower than the target temperature. Joining method.

2. The target temperature is 350° C. or higher. The joining method according to claim 1 .

3. The heat treatment in the first temperature range includes increasing the temperature of an atmosphere in which the first semiconductor substrate and the second semiconductor substrate are provided in a stepwise manner. The joining method according to claim 1 .

4. The heat treatment in the first temperature range includes maintaining the temperature of the atmosphere in a temperature range of 100° C. or more and less than 150° C. The joining method according to claim 3.

5. The heat treatment in the first temperature range includes maintaining the temperature of the atmosphere in a temperature range of 300° C. or more and less than 350° C. The joining method according to claim 3.

6. The heat treatment in the first temperature range includes moving the first semiconductor substrate and the second semiconductor substrate in sequence through a plurality of annealing apparatuses having mutually different set temperatures. The joining method according to claim 3.

7. The heat treatment in the first temperature range includes successively increasing the temperature of an atmosphere in which the first semiconductor substrate and the second semiconductor substrate are disposed. The joining method according to claim 1 .

8. The heat treatment in the first temperature range includes placing the first semiconductor substrate and the second semiconductor substrate in an annealing apparatus and increasing a set temperature of the annealing apparatus to the target temperature at a heating rate of 10° C. / min or less. The joining method according to claim 7.

9. the first semiconductor substrate is a semiconductor wafer; The second semiconductor substrate is a semiconductor wafer. The bonding method according to any one of claims 1 to 8.

10. the first semiconductor substrate is a semiconductor wafer; the second semiconductor substrate is a die; The bonding method according to any one of claims 1 to 8.

11. a first hydrophilization device for hydrophilizing a first surface of a first semiconductor substrate; a second hydrophilization device for hydrophilizing a second surface of a second semiconductor substrate; a bonding device that bonds the first surface of the first semiconductor substrate and the second surface of the second semiconductor substrate; an annealing device that heat-treats the first semiconductor substrate and the second semiconductor substrate to increase a bonding strength between the first semiconductor substrate and the second semiconductor substrate; Equipped with The annealing device is heat treating the first semiconductor substrate and the second semiconductor substrate in a first temperature range; after the heat treatment in the first temperature range, heat treating the first semiconductor substrate and the second semiconductor substrate at a target temperature; configured to run The first temperature range is a temperature range lower than the target temperature. Joining system.

12. The annealing device is a first annealing device for performing the heat treatment in the first temperature range; a second annealing device provided separately from the first annealing device and configured to perform heat treatment at the target temperature; Including, The joint system of claim 11.

13. a substrate transport arm for transporting the first semiconductor substrate and the second semiconductor substrate between the first annealing device and the second annealing device; The joint system of claim 12.

Images