Substrate processing method, bonding system, and semiconductor device

Abstract

This substrate processing method comprises layering a first die and a second die, in this order, on a target substrate. The target substrate has, on the surface thereof which faces the first die, an insulation film and a plurality of electrodes. The first die has, on the surface thereof which faces the target substrate, an insulation film and one or more electrodes, and has, on the surface thereof which faces the second die, an insulation film and one or more electrodes. The second die has, on the surface thereof which faces the first die, an insulation film and one or more electrodes. The substrate processing method comprises bonding together the insulation films of the target substrate and the first die, bonding together electrodes of the target substrate and the first die, bonding together the insulation films of the first die and the second die, and bonding together electrodes of the first die and the second die.

Description

SUBSTRATE PROCESSING METHOD, BONDING SYSTEM, AND SEMICONDUCTOR DEVICE

[0001] The present disclosure relates to a substrate processing method, a bonding system, and a semiconductor device.

[0002] Patent Document 1 describes a technique for bonding individual chips to a substrate. The chips are also called dies.

[0003] Japanese Patent Application Publication No. 2021-197430

[0004] One aspect of the present disclosure provides techniques for increasing die density.

[0005] A substrate processing method according to one aspect of the present disclosure includes stacking a first die and a second die in this order on a target substrate. The target substrate has an insulating film and multiple electrodes on a surface facing the first die. The first die has an insulating film and one or more electrodes on a surface facing the target substrate, and an insulating film and one or more electrodes on a surface facing the second die. The second die has an insulating film and one or more electrodes on a surface facing the first die. The substrate processing method includes bonding insulating films of the target substrate and the first die, bonding electrodes of the target substrate and the first die, bonding insulating films of the first die and the second die, and bonding electrodes of the first die and the second die.

[0006] According to one aspect of the present disclosure, die density is improved.

[0007] FIG. 1 is a cross-sectional view of a semiconductor device according to an embodiment. FIG. 2 is a plan view of a bonding system according to an embodiment. FIG. 3A is a cross-sectional view of an example of a target substrate, FIG. 3B is a cross-sectional view of an example of a plurality of first dies mounted on a first carrier, and FIG. 3C is a cross-sectional view of an example of a plurality of second dies mounted on a second carrier. FIG. 4 is a cross-sectional view of an example of a first bonding apparatus. FIG. 5 is a cross-sectional view of an example of a second bonding apparatus. FIG. 6 is a flowchart showing a substrate processing method according to an embodiment. FIG. 7 is a cross-sectional view of an example of step S4. FIG. 8 is a cross-sectional view of an example of step S5. FIG. 9 is a cross-sectional view of an example of step S6. FIG. 10 is a plan view of a bonding system according to a modified example. FIG. 11 is a flowchart showing a substrate processing method according to a modified example. FIG. 12 is a flowchart showing an example of a subroutine of step S2. FIG. 13A is a cross-sectional view of an example of step S21, FIG. 13B is a cross-sectional view of an example of step S22, and FIG. 13C is a cross-sectional view of an example of step S23. FIG. 14A is a cross-sectional view showing an example of step S24, FIG. 14B is a cross-sectional view showing an example of step S24 subsequent to FIG. 14A, and FIG. 14C is a cross-sectional view showing an example of step S24 subsequent to FIG. 14B. FIG. 15 is a flowchart showing an example of a subroutine of step S21. FIG. 16A is a cross-sectional view showing an example of step S211, FIG. 16B is a cross-sectional view showing an example of step S214, and FIG. 16C is a cross-sectional view showing an example of step S215. FIG. 17A is a cross-sectional view showing an example of step S216, and FIG. 17B is a cross-sectional view showing an example of step S217. FIG. 18 is a flowchart showing an example of a subroutine of step S211. FIG. 19A is a cross-sectional view showing an example of step S2111, FIG. 19B is a cross-sectional view showing an example of step S2112, and FIG. 19C is a cross-sectional view showing an example of step S2113. 20A is a cross-sectional view showing an example of step S2114, FIG. 20B is a cross-sectional view showing an example of step S2115, and FIG. 20C is a cross-sectional view showing an example of step S2116.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the same or corresponding components in each drawing are denoted by the same reference numerals, and descriptions thereof may be omitted. In this specification, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The X-axis direction and Y-axis direction are horizontal directions, and the Z-axis direction is vertical. The X-axis direction includes the positive X-axis direction and the negative X-axis direction that is opposite to the positive X-axis direction. The Y-axis direction includes the positive Y-axis direction and the negative Y-axis direction that is opposite to the positive Y-axis direction. The Z-axis direction includes the positive Z-axis direction and the negative Z-axis direction that is opposite to the positive Z-axis direction.

[0009] A semiconductor device 2 according to one embodiment will be described with reference to Figure 1. The semiconductor device 2 is formed by stacking a first die 20 and a second die 60 in this order on a target substrate 10, for example. The semiconductor device 2 has the target substrate 10, a plurality of first dies 20, and a plurality of second dies 60. The second dies 60 are provided on the opposite side of the target substrate 10 with respect to the first die 20. Note that the semiconductor device 2 may have one first die 20 and one second die 60.

[0010] Although not shown, the semiconductor device 2 may further include a third die, and may be formed by stacking the first die 20, the second die 60, and the third die in this order on the target substrate 10. Alternatively, the semiconductor device 2 may not include the second die 60, and may be formed by stacking the first die 20 on the target substrate 10.

[0011] The target substrate 10 has an insulating film 12 and multiple electrodes 13 on its surface 10a facing the first die 20. The insulating film 12 is, for example, a silicon oxide film. Silicon oxide films can be bonded together through hydrogen bonding between OH groups. After bonding, the bonding strength can be increased by a dehydration condensation reaction. The surface of the silicon oxide film may be activated with plasma before bonding, and then OH groups may be added to the surface by supplying water molecules. The silicon oxide film is formed using, for example, TEOS (Tetraethoxysilane). The insulating film 12 is formed on a semiconductor substrate 11. In this embodiment, the semiconductor substrate 11 is a silicon wafer, but it may also be a compound semiconductor wafer. A conductive film (not shown) or the like may be provided between the semiconductor substrate 11 and the insulating film 12. The multiple electrodes 13 are provided in openings in the insulating film 12.

[0012] The first die 20 has an insulating film (e.g., a first insulating film 32 described later) and one or more electrodes (e.g., a first electrode 33 described later) on a surface 20a facing the target substrate 10. The first die 20 also has an insulating film (e.g., a sixth insulating film 54 described later) and one or more electrodes (e.g., a sixth electrode 55 described later) on a surface 20b facing the second die 60. The surfaces 20a and 20b face opposite each other. The insulating film is, for example, a silicon oxide film and is formed using, for example, TEOS.

[0013] The first die 20 is formed, for example, by stacking a second laminate substrate 40 and a third laminate substrate 50 on a first laminate substrate 30 in this order. The first die 20 has the first laminate substrate 30, the second laminate substrate 40, and the third laminate substrate 50 in this order. Although not shown, the first die 20 may further have a fourth laminate substrate, or may have the first laminate substrate 30, the second laminate substrate 40, the third laminate substrate 50, and the fourth laminate substrate in this order. Furthermore, the first die 20 does not need to have the third laminate substrate 50, and may instead be formed by stacking the second laminate substrate 40 on the first laminate substrate 30.

[0014] The first laminated substrate 30 has a first semiconductor substrate 31. In this embodiment, the first semiconductor substrate 31 is a silicon wafer, but it may also be a compound semiconductor wafer. The first laminated substrate 30 has a first insulating film 32 formed on one side of the first semiconductor substrate 31 and a first electrode 33 provided in an opening in the first insulating film 32. The first laminated substrate 30 also has a second insulating film 34 formed on the opposite side of the first semiconductor substrate 31 and a second electrode 35 provided in the opening in the second insulating film 34. The first electrode 33 and the second electrode 35 are electrically connected.

[0015] The second laminate substrate 40 has a second semiconductor substrate 41. In this embodiment, the second semiconductor substrate 41 is a silicon wafer, but it may be a compound semiconductor wafer. The second laminate substrate 40 has a third insulating film 42 formed on one side of the second semiconductor substrate 41 and a third electrode 43 provided in an opening in the third insulating film 42. The second laminate substrate 40 also has a fourth insulating film 44 formed on the opposite side of the second semiconductor substrate 41 and a fourth electrode 45 provided in the opening in the fourth insulating film 44. The third electrode 43 and the fourth electrode 45 are electrically connected.

[0016] The third laminate substrate 50 has a third semiconductor substrate 51. In this embodiment, the third semiconductor substrate 51 is a silicon wafer, but may be a compound semiconductor wafer. The third laminate substrate 50 has a fifth insulating film 52 formed on one side of the third semiconductor substrate 51 and a fifth electrode 53 provided in an opening in the fifth insulating film 52. The third laminate substrate 50 also has a sixth insulating film 54 formed on the opposite side of the third semiconductor substrate 51 and a sixth electrode 55 provided in the opening in the sixth insulating film 54. The fifth electrode 53 and the sixth electrode 55 are electrically connected.

[0017] The insulating film 12 of the target substrate 10 and the first insulating film 32 of the first laminated substrate 30 are in contact with each other and bonded together. Furthermore, the electrode 13 of the target substrate 10 and the first electrode 33 of the first laminated substrate 30 are in contact with each other and bonded together. The electrode 13 and the first electrode 33 are electrically connected together. The number of electrodes 13 and first electrodes 33 is not particularly limited.

[0018] The second insulating film 34 of the first laminate substrate 30 and the third insulating film 42 of the second laminate substrate 40 are in contact with each other and bonded together. Furthermore, the second electrode 35 of the first laminate substrate 30 and the third electrode 43 of the second laminate substrate 40 are in contact with each other and bonded together. The second electrode 35 and the third electrode 43 are electrically connected together. The number of second electrodes 35 and third electrodes 43 is not particularly limited.

[0019] The fourth insulating film 44 of the second laminate substrate 40 and the fifth insulating film 52 of the third laminate substrate 50 are in contact with each other and bonded together. Furthermore, the fourth electrode 45 of the second laminate substrate 40 and the fifth electrode 53 of the third laminate substrate 50 are in contact with each other and bonded together. The fourth electrode 45 and the fifth electrode 53 are electrically connected together. The number of the fourth electrodes 45 and the fifth electrodes 53 is not particularly limited.

[0020] The second die 60 has an insulating film 62 and one or more electrodes 63 on a surface 60a facing the first die 20. The insulating film 62 is, for example, a silicon oxide film, and is formed using, for example, TEOS. The electrodes 63 are provided in openings in the insulating film 62.

[0021] The second die 60 may be formed by stacking multiple laminated substrates, similar to the first die 20. The structure of the second die 60 is similar to that of the first die 20, so a detailed description thereof will be omitted. The second die 60 may have the same function as the first die 20, or may have a different function.

[0022] An insulating film (e.g., the sixth insulating film 54) of the first die 20 and an insulating film 62 of the second die 60 are in contact with each other and bonded together. Also, an electrode (e.g., the sixth electrode 55) of the first die 20 and an electrode 63 of the second die 60 are in contact with each other and bonded together. The sixth electrode 55 and the electrode 63 are electrically connected together. The number of the sixth electrodes 55 and the electrodes 63 is not particularly limited.

[0023] When the semiconductor device 2 has a third die (not shown), the second die 60 has an insulating film 64 and one or more electrodes 65 on a surface 60b facing the third die. The surfaces 60a and 60b face opposite each other. The electrode 65 is provided in an opening in the insulating film 64. The third die has an insulating film and one or more electrodes on a surface facing the second die 60.

[0024] The insulating film 64 of the second die 60 and the insulating film of the third die are in contact with each other and bonded together. Also, the electrodes 65 of the second die 60 and the electrodes of the third die are in contact with each other and bonded together. The electrodes 65 of the second die 60 and the electrodes of the third die are electrically connected together. The number of electrodes (e.g., electrodes 65) is not particularly limited.

[0025] According to this embodiment, the target substrate 10, the first die 20, and the second die 60 are stacked without using bumps. This allows for improved integration of the dies. Furthermore, the first laminate substrate 30, the second laminate substrate 40, and the third laminate substrate 50 that constitute the first die 20 are stacked without using bumps. This allows for improved integration of the semiconductor circuit.

[0026] Next, a bonding system 101 according to one embodiment will be described, mainly with reference to Figures 2 to 5. The bonding system 101 stacks a first die 20 and a second die 60 in this order on a target substrate 10. In other words, the bonding system 101 manufactures a semiconductor device 2. As described above, the semiconductor device 2 does not necessarily have to include the second die 60, and may instead be formed by stacking the first die 20 on the target substrate 10.

[0027] 2, the bonding system 101 includes a loading / unloading station 110, a processing station 120, and a control circuit 190. The loading / unloading station 110 and the processing station 120 are arranged in this order from the negative side of the X-axis to the positive side of the X-axis.

[0028] The carry-in / out station 110 includes a mounting table 102. Cassettes C101 to C106 are mounted on the mounting table 102. Cassette C101 stores the target substrate 10 shown in FIG. 3A. Cassette C102 stores the first carrier 70 on which a plurality of first dies 20 are mounted, as shown in FIG. 3B. Cassette C103 stores the first carrier 70 from which the first dies 20 have been removed.

[0029] The first carrier 70 includes, for example, a frame 71 and a tape 72 that covers an opening of the frame 71. A plurality of first dies 20 are arranged on the tape 72. Although not shown, the first carrier 70 may be an electrostatic carrier. The electrostatic carrier electrostatically attracts the first die 20. The electrostatic carrier may have a size approximately the same as that of the target substrate 10. The electrostatic carrier has a carrier substrate and a resin film, and the first die 20 is attached to the opposite side of the resin film from the carrier substrate.

[0030] The resin film may have adhesive properties. The first die 20 may be adsorbed to the resin film by pressing the first die 20 against the resin film. By pressing the first die 20 against the resin film, the resin film can be deformed so as to remove gas from between the first die 20 and the resin film, and the first die 20 can be vacuum-adsorbed to the resin film. Therefore, the first carrier 70 does not have to be an electrostatic carrier.

[0031] The cassette C104 stores the second carrier 80 on which a plurality of second dies 60 are mounted, as shown in FIG. 3C . The cassette C105 stores the second carrier 80 from which the second dies 60 have been peeled off. The second carrier 80 includes, for example, a frame 81 and a tape 82 that covers the opening of the frame 81. The plurality of second dies 60 are arranged on the tape 82. Note that the second carrier 80 may be formed of a carrier substrate and a resin film, similar to the first carrier 70.

[0032] The cassette C106 accommodates the semiconductor device 2.

[0033] The loading / unloading station 110 includes a transfer area 111 and a transfer device 112. The transfer area 111 is adjacent to the mounting table 102. The transfer area 111 extends in the Y-axis direction. The transfer device 112 includes a substrate transfer arm 112a and a carrier transfer arm 112b. The substrate transfer arm 112a holds and transfers a target substrate 10 in the transfer area 111. The target substrate 10 to be transferred may be one before the first die 20 and the like are bonded to it, or one after the first die 20 and the like have been bonded to it. The carrier transfer arm 112b holds and transfers a first carrier 70 or a second carrier 80 in the transfer area 111. The first carrier 70 or the second carrier 80 to be transferred may be one to which the first die 20 or the second die 60 is attached, or one from which the first die 20 or the second die 60 has been peeled off.

[0034] The transfer device 112 has a drive unit (not shown) that moves or rotates the substrate transfer arm 112 a and the carrier transfer arm 112 b. The substrate transfer arm 112 a and the carrier transfer arm 112 b can move horizontally (in both the X-axis and Y-axis directions) and vertically (in the Z-axis direction), and can rotate around a vertical axis.

[0035] 2, the substrate transport arm 112a and the carrier transport arm 112b may be mounted on the same Y-axis slider and moved simultaneously in the Y-axis direction, or may be mounted on different Y-axis sliders and moved independently in the Y-axis direction. The substrate transport arm 112a and the carrier transport arm 112b are disposed at different heights.

[0036] The processing station 120 includes a first bonding device 130, a second bonding device 140, and a heating device 150. The first bonding device 130, the second bonding device 140, and the heating device 150 are adjacent to the transfer region 111. The first bonding device 130 bonds the target substrate 10 and the first die 20. The second bonding device 140 bonds the first die 20 and the second die 60. The heating device 150 heats the target substrate 10, the first die 20, and the second die 60.

[0037] The control circuit 190 is, for example, a computer, and includes an arithmetic unit 191 such as a CPU (Central Processing Unit), and a storage unit 192 such as a memory. The storage unit 192 stores programs that control various processes executed in the bonding system 101. The control circuit 190 controls the operation of the bonding system 101 by causing the arithmetic unit 191 to execute the programs stored in the storage unit 192. A device control unit that controls the operation of each device constituting the bonding system 101 may be provided, and a system control unit that controls multiple device control units may be provided. The device control units and the system control unit may form the control circuit 190.

[0038] The control circuit 190 includes electronic circuits such as a CPU, a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC), and performs the various control operations described in this specification by executing instruction codes stored in a memory or by being a circuit designed for a specific application.

[0039] Next, an example of the first bonding device 130 will be described with reference to FIG. 4 . The first bonding device 130 includes, for example, a carrier holding unit 131, a substrate holding unit 132, a transport unit 133, and a mount unit 134. The carrier holding unit 131 holds the first carrier 70. The substrate holding unit 132 holds the target substrate 10. The transport unit 133 receives and transports the first die 20 from the first carrier 70 held by the carrier holding unit 131. In this embodiment, there is one transport unit 133, but there may be multiple transport units 133. The mount unit 134 receives the first die 20 from the transport unit 133 and bonds the received first die 20 to the target substrate 10 held by the substrate holding unit 132.

[0040] The carrier holding unit 131 holds the first carrier 70 horizontally. The substrate holding unit 132 holds the target substrate 10 horizontally. The transport unit 133 peels the first die 20 from the first carrier 70 and transports it. The transport unit 133 may turn the first die 20 upside down while transporting it. The mount unit 134 receives the first die 20 from the transport unit 133 and bonds the received first die 20 to the target substrate 10 held by the substrate holding unit 132.

[0041] The transport unit 133 has, for example, a suction head 133a and a movement mechanism 133b. The suction head 133a suctions the first die 20. The suction head 133a may suction the first die 20 in a non-contact manner. The movement mechanism 133b moves the suction head 133a. The movement mechanism 133b may turn the suction head 133a upside down, thereby turning the first die 20 upside down.

[0042] The first bonding device 130 may include a pressing unit 135. The pressing unit 135 presses only one first die 20 by, for example, locally pressing the first carrier 70. The pressing unit 135 presses the first die 20 in a direction to peel it off from the first carrier 70. Note that if the first die 20 can be peeled off from the first carrier 70 simply by the transport unit 133 lifting the first die 20 together with the suction head 133 a, the pressing unit 135 may not be required.

[0043] The mount unit 134 has, for example, a suction head 134a and a movement mechanism 134b. The suction head 134a suctions the first die 20 from the side opposite to the suction head 133a. The suction head 134a may suction the first die 20 in a non-contact manner. The movement mechanism 134b moves the suction head 134a to bond the first die 20 to the target substrate 10.

[0044] The first bonding device 130 may include an imaging unit (not shown) to improve the accuracy of the bonding position of the first die 20 relative to the target substrate 10. The imaging unit captures an image of an alignment mark on the bonding surface of the target substrate 10 or the first die 20. The alignment mark may be a dedicated mark or may be part of an electrical circuit. The imaging unit does not need to capture an image every time the first die 20 and the target substrate 10 are bonded, and may capture images periodically.

[0045] Next, an example of the second bonding device 140 will be described with reference to FIG. 5 . The second bonding device 140 includes, for example, a carrier holding unit 141, a substrate holding unit 142, a transport unit 143, and a mount unit 144. The carrier holding unit 141 holds the second carrier 80. The substrate holding unit 142 holds the target substrate 10. The transport unit 143 receives and transports the second die 60 from the second carrier 80 held by the carrier holding unit 141. In this embodiment, there is one transport unit 143, but there may be multiple transport units 143. The mount unit 144 receives the second die 60 from the transport unit 143 and bonds the received second die 60 to the first die 20 held by the substrate holding unit 142.

[0046] The carrier holding unit 141 holds the second carrier 80 horizontally. The substrate holding unit 142 holds the target substrate 10 horizontally. The transport unit 143 peels the second die 60 from the second carrier 80 and transports it. The transport unit 143 may turn the second die 60 upside down while transporting it. The mount unit 144 receives the second die 60 from the transport unit 143 and bonds the received second die 60 to the first die 20.

[0047] The transport unit 143 has, for example, a suction head 143a and a movement mechanism 143b. The suction head 143a suctions the second die 60. The suction head 143a may suction the second die 60 in a non-contact manner. The movement mechanism 143b moves the suction head 143a. The movement mechanism 143b may turn the suction head 143a upside down, thereby turning the second die 60 upside down.

[0048] The second bonding device 140 may include a pressing unit 145. The pressing unit 145 presses only one second die 60, for example, by locally pressing the second carrier 80. The pressing unit 145 presses the second die 60 in a direction to peel it off from the second carrier 80. Note that if the second die 60 can be peeled off from the second carrier 80 simply by the transport unit 143 lifting the second die 60 together with the suction head 143 a, the pressing unit 145 may be omitted.

[0049] The mount unit 144 has, for example, a suction head 144a and a movement mechanism 144b. The suction head 144a suctions the second die 60 from the side opposite to the suction head 143a. The suction head 144a may suction the second die 60 in a non-contact manner. The movement mechanism 144b moves the suction head 144a to bond the second die 60 to the first die 20.

[0050] The second bonding device 140 may include an imaging unit (not shown) to improve the accuracy of the bonding position of the second die 60 relative to the first die 20. The imaging unit captures an image of an alignment mark on the bonding surface of the first die 20 or the second die 60. The alignment mark may be a dedicated mark or may be part of an electric circuit. The imaging unit does not need to capture an image every time the second die 60 and the first die 20 are bonded, and may capture images periodically.

[0051] Next, a substrate processing method according to one embodiment will be described with reference to Figures 6 to 9. The substrate processing method includes, for example, steps S1 to S6. Preparing the target substrate 10 (step S1) includes, for example, placing a cassette C101 on the mounting table 102. Preparing the first die 20 (step S2) includes, for example, placing a cassette C102 on the mounting table 102. Preparing the second die 60 (step S3) includes placing a cassette C104 on the mounting table 102.

[0052] The substrate transport arm 112a removes the target substrate 10 from the cassette C101 and transports it to the first bonding device 130. Furthermore, the carrier transport arm 112b removes the first carrier 70, on which the first die 20 is mounted, from the cassette C102 and transports it to the first bonding device 130. Next, the first bonding device 130 peels the first die 20 from the first carrier 70 and bonds it to the target substrate 10 (step S4).

[0053] Step S4 includes bonding the insulating films (e.g., insulating film 12 and first insulating film 32) of the target substrate 10 and the first die 20 together, as shown in FIG. 7 . The electrode 13 and the first electrode 33 may be recessed relative to the interface between the insulating film 12 and the first insulating film 32 and may not be in contact with each other. The electrode is softer than the insulating film. Therefore, by polishing both the electrode and the insulating film simultaneously, a step can be formed between the electrode and the insulating film.

[0054] After step S4, the substrate transport arm 112a removes the target substrate 10 bonded to the first die 20 from the first bonding device 130 and transports it to the second bonding device 140. Also, the carrier transport arm 112b removes the second carrier 80, on which the second die 60 is mounted, from the cassette C104 and transports it to the second bonding device 140. Next, the second bonding device 140 peels the second die 60 from the second carrier 80 and bonds it to the first die 20 (step S5).

[0055] Step S5 includes bonding the insulating films (e.g., the sixth insulating film 54 and the insulating film 62) of the first die 20 and the second die 60 together, as shown in FIG. 8 . The sixth electrode 55 and the electrode 63 may be recessed relative to the interface between the sixth insulating film 54 and the insulating film 62 and may not be in contact with each other. The electrode is softer than the insulating film. Therefore, by polishing both the electrode and the insulating film simultaneously, a step can be formed between the electrode and the insulating film.

[0056] After step S5, the substrate transfer arm 112a removes the target substrate 10, to which the first die 20 and the second die 60 have been bonded, from the second bonding device 140 and transfers it to the heating device 150. Next, the heating device 150 heats the target substrate 10, the first die 20, and the second die 60 (step S6).

[0057] As shown in FIG. 9 , step S6 involves simultaneously bonding the electrodes of the target substrate 10 and the first die 20 (e.g., electrode 13 and first electrode 33) and bonding the electrodes of the first die 20 and the second die 60 (e.g., sixth electrode 55 and electrode 63). This reduces the number of processes. Note that electrodes have a larger thermal expansion coefficient than insulating films. Therefore, separated electrodes can be brought into contact with each other by heating and bonded. The electrodes are diffusion bonded.

[0058] After step S6, the substrate transport arm 112a removes the target substrate 10, to which the first die 20 and the second die 60 have been bonded, from the heating device 150 and transports it to the cassette C106. The carrier transport arm 112b removes the first carrier 70, from which the first die 20 has been peeled, from the first bonding device 130 and transports it to the cassette C103. The carrier transport arm 112b also removes the second carrier 80, from which the second die 60 has been peeled, from the second bonding device 140 and transports it to the cassette C105.

[0059] Next, a bonding system 101 according to a modified example will be described with reference to FIG. 10 . Differences from the above embodiment will be mainly described below. The processing station 120 includes a first bonding device 130, a second bonding device 140, a first heating device 150A, and a second heating device 150B. The first heating device 150A heats the target substrate 10 and the first die 20 after bonding the target substrate 10 and the first die 20 and before bonding the first die 20 and the second die 60. The second heating device 150B heats the first die 20 and the second die 60 after bonding the first die 20 and the second die 60. Note that the second heating device 150B may also heat the target substrate 10.

[0060] Next, a substrate processing method according to a modified example will be described with reference to FIG. 11 . Differences from the above embodiment will be mainly described below. The substrate processing method includes steps S6A and S6B instead of step S6. Step S6A includes, after step S4 and before step S5, heating the target substrate 10 and the first die 20 to bond electrodes of the target substrate 10 and the first die 20 (e.g., electrode 13 and first electrode 33). Step S6B includes, after step S5, heating the first die 20 and the second die 60 to bond electrodes of the first die 20 and the second die 60 (e.g., sixth electrode 55 and electrode 63).

[0061] Next, an example of a subroutine of step S2 shown in Fig. 6 and Fig. 11 will be described with reference to Fig. 12 to Fig. 14. As shown in Fig. 12, step S2 includes, for example, steps S21 to S24. As shown in Fig. 13A, step S21 includes preparing a first substrate 21 supported by a first support substrate 36. The first substrate 21 is a substrate before being singulated into a plurality of first dies 20, and includes, for example, a first laminate substrate 30, a second laminate substrate 40, and a third laminate substrate 50.

[0062] 13B, step S22 includes singulating the first substrate 21 into a plurality of first dies 20. The singulation method is not particularly limited, but may be, for example, plasma dicing or laser dicing. Compared to blade dicing, plasma dicing and laser dicing enable singulation with a high aspect ratio and narrow streets.

[0063] 13C, step S23 includes mounting a plurality of first dies 20 on a first carrier 70. The first carrier 70 includes, for example, a frame 71 and a tape 72 that covers an opening of the frame 71. The plurality of first dies 20 are arranged on the tape 72. Note that step S22 is performed before step S23 in order to prevent deterioration of the tape 72 due to plasma or laser.

[0064] Step S24 includes peeling off the multiple first dies 20 from the first support substrate 36, as shown in Figures 14(A) to 14(C). For example, first, as shown in Figure 14(A), a laser beam LB is irradiated onto the interface between the first support substrate 36 and the first die 20 from the side opposite to the first die 20 to form a modified layer 22. A plurality of modified layers 22 are provided at intervals. The modified layer 22 may be formed inside the first support substrate 36. Note that the formation of the modified layer 22 does not necessarily have to be performed.

[0065] Next, as shown in Fig. 14(B), a blade 23 is inserted into the interface between the first support substrate 36 and the first die 20 to form a peeling start point. Next, as shown in Fig. 14(C), the first support substrate 36 is peeled off from the first die 20. Thereafter, although not shown, the peeled surface of the first die 20 may be polished. Polishing can form a step between the electrode and the insulating film.

[0066] Steps S21 to S24 result in a plurality of first dies 20 (see FIG. 3B) mounted on the first carrier 70. Note that a plurality of second dies 60 (see FIG. 3C) mounted on the second carrier 80 are obtained in the same manner as the plurality of first dies 20 mounted on the first carrier 70, and therefore detailed description thereof will be omitted.

[0067] Next, an example of a subroutine of step S21 shown in Fig. 12 will be described with reference to Figs. 15 to 17. As shown in Fig. 15, step S21 includes, for example, steps S211 to S217. As shown in Fig. 16A, step S211 includes preparing a first laminate substrate 30 supported by a first support substrate 36. Although not shown, step S212 includes preparing a second laminate substrate 40 supported by a second support substrate. Although not shown, step S213 includes preparing a third laminate substrate 50 supported by a third support substrate.

[0068] 16B , step S214 includes bonding the first laminate substrate 30 supported by the first support substrate 36 to the second laminate substrate 40 supported by the second support substrate 46. The bonding of the first laminate substrate 30 and the second laminate substrate 40 may be performed in the same manner as the bonding of the first die 20 and the second die 60. For example, insulating films (e.g., the second insulating film 34 and the third insulating film 42) are bonded together, and then electrodes (e.g., the second electrode 35 and the third electrode 43) are bonded together.

[0069] Step S215 includes peeling the second laminate substrate 40 from the second support substrate 46, as shown in FIG. 16C. Peeling the second laminate substrate 40 from the second support substrate 46 may be performed in the same manner as peeling the first dies 20 from the first support substrate 36 (step S24 shown in FIG. 12). Thereafter, although not shown, the peeled surface of the second laminate substrate 40 may be polished. Polishing can form a step between the electrode and the insulating film.

[0070] 17A , step S216 includes bonding the second laminate substrate 40 and the third laminate substrate 50 supported by the third support substrate 56. The bonding of the second laminate substrate 40 and the third laminate substrate 50 may be performed in the same manner as the bonding of the first die 20 and the second die 60. For example, insulating films (e.g., the fourth insulating film 44 and the fifth insulating film 52) are bonded together, and then electrodes (e.g., the fourth electrode 45 and the fifth electrode 53) are bonded together.

[0071] Step S217 includes peeling the third laminate substrate 50 from the third support substrate 56, as shown in FIG. 17B. Peeling the third laminate substrate 50 from the third support substrate 56 may be performed in the same manner as peeling the first dies 20 from the first support substrate 36 (step S24 shown in FIG. 12). Thereafter, although not shown, the peeled surface of the third laminate substrate 50 may be polished. Polishing can form a step between the electrode and the insulating film.

[0072] Steps S211 to S217 result in a first substrate 21 (see FIG. 13A) supported by a first support substrate 36. The first substrate 21 is composed of a first laminate substrate 30, a second laminate substrate 40, and a third laminate substrate 50. Note that the bonding of the electrodes of the first laminate substrate 30 and the second laminate substrate 40, and the bonding of the electrodes of the second laminate substrate 40 and the third laminate substrate 50 may be performed all at once. This reduces the number of steps.

[0073] 18 to 20, an example of a subroutine of step S211 shown in Fig. 15 will be described. As shown in Fig. 18, step S211 includes, for example, steps S2111 to S2116. As shown in Fig. 19A, step S2111 includes forming a first insulating film 32 on one surface of a first semiconductor substrate 31 and forming a first electrode 33 in an opening in the first insulating film 32.

[0074] 19B, step S2112 includes bonding the first support substrate 36 and the first semiconductor substrate 31. The first support substrate 36 includes a semiconductor substrate 38 and an insulating film 37 formed on the semiconductor substrate 38. The insulating film 37 of the first support substrate 36 is bonded to the first insulating film 32. These insulating films are, for example, silicon oxide films, and are formed using, for example, TEOS.

[0075] Step S2113 includes thinning the first semiconductor substrate 31, as shown in FIG. 19C . The thinning includes, for example, grinding. The first semiconductor substrate 31 can be thinned by grinding the first semiconductor substrate 31 from the side opposite to the first support substrate 36. Note that the thinning may include laser processing. In addition to thinning the first semiconductor substrate 31, step S2113 may also include trimming the periphery of the first semiconductor substrate 31. The bevel of the first semiconductor substrate 31 can be removed. The trimming includes, for example, laser processing. The trimming is performed before the thinning.

[0076] 20A, step S2114 includes selectively etching the first semiconductor substrate 31 relative to the first insulating film 32. The etching may include, for example, plasma etching. Note that the first electrode 33 is protected by the first insulating film 32 and is not etched. The first insulating film 32 and the first electrode 33 protrude from the opposite surface of the first semiconductor substrate 31.

[0077] 20B, step S2115 includes forming a second insulating film 34 on the opposite surface of the first semiconductor substrate 31 (the surface opposite to the first support substrate 36). The second insulating film 34 is formed by, for example, a chemical vapor deposition (CVD) method. The second insulating film 34 is, for example, a silicon oxide film, and is formed using, for example, TEOS.

[0078] 20C , step S2116 includes planarizing the second insulating film 34. Planarizing the second insulating film 34 includes, for example, chemical mechanical polishing (CMP). By planarizing the second insulating film 34 with a polishing machine 39, the second electrode 35 is provided in the opening of the second insulating film 34.

[0079] Steps S2111 to S2116 result in a first laminate substrate 30 (see FIG. 16A) supported by the first support substrate 36. Note that the second laminate substrate 40 supported by the second support substrate 46 and the third laminate substrate 50 supported by the third support substrate 56 are obtained in the same manner as the first laminate substrate 30 supported by the first support substrate 36, and therefore detailed explanations thereof will be omitted.

[0080] Although the embodiments of the substrate processing method, bonding system, and semiconductor device according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0081] This application claims priority based on Japanese Patent Application No. 2023-190259 filed with the Japan Patent Office on November 7, 2023, the entire contents of which are incorporated herein by reference.

[0082] 10 Target substrate 10a Opposing surface 12 Insulating film 13 Electrode 20 First die 20a Opposing surface 20b Opposing surface 32 First insulating film 33 First electrode 54 Sixth insulating film 55 Sixth electrode 60 Second die 60a Opposing surface 62 Insulating film 63 Electrode

Claims

1. A substrate processing method comprising stacking a first die and a second die in this order on a target substrate, wherein the target substrate has an insulating film and a plurality of electrodes on a surface facing the first die, the first die has an insulating film and one or more electrodes on a surface facing the target substrate, and also has an insulating film and one or more electrodes on a surface facing the second die, and the second die has an insulating film and one or more electrodes on a surface facing the first die, the substrate processing method comprising bonding the insulating films of the target substrate and the first die, bonding the electrodes of the target substrate and the first die, bonding the insulating films of the first die and the second die, and bonding the electrodes of the first die and the second die.

2. A substrate processing method as described in claim 1, wherein bonding the insulating films of the target substrate and the first die and bonding the insulating films of the first die and the second die are performed in this order, and then the target substrate, the first die, and the second die are heated to bond the electrodes of the target substrate and the first die and bond the electrodes of the first die and the second die together in a single process.

3. The substrate processing method of claim 1, comprising the steps of: bonding insulating films of the target substrate and the first die; heating the target substrate and the first die to bond electrodes of the target substrate and the first die; bonding insulating films of the first die and the second die; and heating the first die and the second die to bond electrodes of the first die and the second die, in this order.

4. The substrate processing method according to any one of claims 1 to 3, wherein the insulating film formed on the surface of the first die facing the target substrate is formed using TEOS (Tetraethoxysilane).

5. The substrate processing method according to claim 1, wherein the insulating film formed on the surface of the first die facing the second die is formed using TEOS (Tetraethoxysilane).

6. The substrate processing method according to any one of claims 1 to 3, wherein the substrate processing method comprises stacking the first die, the second die, and the third die in this order on the target substrate, the second die having an insulating film and one or more electrodes on a surface facing the third die, and the third die having an insulating film and one or more electrodes on a surface facing the second die, and the substrate processing method comprises bonding the insulating films of the second die and the third die to each other, and bonding the electrodes of the second die and the third die to each other.

7. The substrate processing method according to any one of claims 1 to 3, wherein the first die has a first laminated substrate and a second laminated substrate, the first laminated substrate having a first semiconductor substrate, a first insulating film formed on one side of the first semiconductor substrate, a first electrode provided in an opening of the first insulating film, a second insulating film formed on the opposite side of the first semiconductor substrate, and a second electrode provided in the opening of the second insulating film, the first electrode and the second electrode being electrically connected, the second laminated substrate having a second semiconductor substrate, a third insulating film formed on one side of the second semiconductor substrate, a third electrode provided in the opening of the third insulating film, a fourth insulating film formed on the opposite side of the second semiconductor substrate, and a fourth electrode provided in the opening of the fourth insulating film, the third electrode and the fourth electrode being electrically connected, the second insulating film of the first laminated substrate and the third insulating film of the second laminated substrate being in contact with each other and being bonded, and the second electrode of the first laminated substrate and the third electrode of the second laminated substrate being in contact with each other and being bonded.

8. A substrate processing method comprising stacking a first die on a target substrate, wherein the target substrate has an insulating film and a plurality of electrodes on a surface facing the first die, and the first die has an insulating film and one or more electrodes on a surface facing the target substrate, the substrate processing method comprises bonding insulating films of the target substrate and the first die together, and bonding electrodes of the target substrate and the first die together, the first die having a first laminated substrate and a second laminated substrate, the first laminated substrate having a first semiconductor substrate, a first insulating film formed on one surface of the first semiconductor substrate, a first electrode provided in an opening of the first insulating film, a second insulating film formed on an opposite surface of the first semiconductor substrate, and a second electrode provided in an opening of the second insulating film, the first electrode and the second electrode being electrically connected, the second laminated substrate has a second semiconductor substrate, a third insulating film formed on one side of the second semiconductor substrate, a third electrode provided in an opening of the third insulating film, a fourth insulating film formed on an opposite side of the second semiconductor substrate, and a fourth electrode provided in an opening of the fourth insulating film, the third electrode and the fourth electrode are electrically connected, the second insulating film of the first laminated substrate and the third insulating film of the second laminated substrate are in contact with each other and bonded, and the second electrode of the first laminated substrate and the third electrode of the second laminated substrate are in contact with each other and bonded.

9. The substrate processing method of claim 8, comprising: singulating a first substrate composed of the first laminated substrate and the second laminated substrate into a plurality of the first dies; and comprising the steps of: preparing the first laminated substrate supported by a first support substrate; preparing the second laminated substrate supported by a second support substrate; bonding the first laminated substrate and the second laminated substrate; and peeling off the second laminated substrate and the second support substrate after bonding the first laminated substrate and the second laminated substrate, prior to singulating the first substrate into a plurality of the first dies.

10. The substrate processing method of claim 8, wherein the first die further comprises a third laminated substrate, the third laminated substrate having a third semiconductor substrate, a fifth insulating film formed on one side of the third semiconductor substrate, a fifth electrode provided in an opening of the fifth insulating film, a sixth insulating film formed on the opposite side of the third semiconductor substrate, and a sixth electrode provided in an opening of the sixth insulating film, the fifth electrode and the sixth electrode being electrically connected, the fourth insulating film of the second laminated substrate and the fifth insulating film of the third laminated substrate being in contact with each other and bonded to each other, and the fourth electrode of the second laminated substrate and the fifth electrode of the third laminated substrate being in contact with each other and bonded to each other.

11. The substrate processing method of claim 10, comprising singulating a first substrate constituted by the first laminate substrate, the second laminate substrate, and the third laminate substrate into a plurality of the first dies, the method comprising the steps of: preparing the first laminate substrate supported by a first support substrate; preparing the second laminate substrate supported by a second support substrate; preparing the third laminate substrate supported by a third support substrate; bonding the first laminate substrate and the second laminate substrate; peeling the second laminate substrate and the second support substrate after bonding the first laminate substrate and the second laminate substrate; peeling the second laminate substrate and the second support substrate after peeling the second laminate substrate and the second support substrate, bonding the second laminate substrate and the third laminate substrate; and peeling the third laminate substrate and the third support substrate after bonding the second laminate substrate and the third laminate substrate, before singulating the first substrate into a plurality of the first dies.

12. A bonding system for stacking a first die and a second die in this order on a target substrate, wherein the target substrate has an insulating film and a plurality of electrodes on a surface facing the first die, the first die has an insulating film and one or more electrodes on a surface facing the target substrate and also has an insulating film and one or more electrodes on a surface facing the second die, and the second die has an insulating film and one or more electrodes on a surface facing the first die, the bonding system comprising: a first bonding device that bonds the insulating films of the target substrate and the first die together, and a second bonding device that bonds the insulating films of the first die and the second die together.

13. The bonding system according to claim 12, further comprising a heating device that heats the target substrate, the first die, and the second die to simultaneously bond the electrodes of the target substrate and the first die to each other, and bond the electrodes of the first die to each other.

14. The bonding system of claim 12, comprising: a first heating device that heats the target substrate and the first die to bond electrodes of the target substrate and the first die together; and a second heating device that heats the first die and the second die to bond electrodes of the first die and the second die together.

15. A semiconductor device having a target substrate and a first die, wherein the target substrate has an insulating film and an electrode provided in an opening of the insulating film on one side, the first die has a first laminate substrate and a second laminate substrate, the first laminate substrate has a first semiconductor substrate, a first insulating film formed on one side of the first semiconductor substrate, a first electrode provided in the opening of the first insulating film, a second insulating film formed on the opposite side of the first semiconductor substrate, and a second electrode provided in the opening of the second insulating film, the first electrode and the second electrode being electrically connected, the second laminate substrate has a second semiconductor substrate, a third insulating film formed on one side of the second semiconductor substrate, a third electrode provided in the opening of the third insulating film, a fourth insulating film formed on the opposite side of the second semiconductor substrate, and a fourth electrode provided in the opening of the fourth insulating film, the third electrode and the fourth electrode being electrically connected, a semiconductor device in which the insulating film of the target substrate and the first insulating film of the first laminated substrate are in contact with each other and bonded, the electrode of the target substrate and the first electrode of the first laminated substrate are in contact with each other and bonded, the second insulating film of the first laminated substrate and the third insulating film of the second laminated substrate are in contact with each other and bonded, and the second electrode of the first laminated substrate and the third electrode of the second laminated substrate are in contact with each other and bonded.