Substrate processing method and substrate processing system

Abstract

This substrate processing method includes: preparing a die-equipped substrate that comprises a substrate and a plurality of dies that are arranged side-by-side on a main surface of the substrate, and that has an uneven surface formed by the substrate and the plurality of dies; laminating a flexible sheet onto the uneven surface of the die-equipped substrate; and heating the flexible sheet after the flexible sheet is laminated. The heated flexible sheet is an insulation film that contains an inorganic compound.

Description

Substrate processing method and substrate processing system

[0001] The present disclosure relates to a substrate processing method and a substrate processing system.

[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 a technique for forming an insulating film containing an inorganic compound on an uneven surface formed by a substrate and a plurality of dies.

[0005] A substrate processing method according to one aspect of the present disclosure includes: preparing a die-mounted substrate having a substrate and a plurality of dies arranged at intervals on a main surface of the substrate, the die-mounted substrate having an uneven surface formed by the substrate and the plurality of dies; laminating a flexible sheet onto the uneven surface of the die-mounted substrate; and heating the flexible sheet after laminating the flexible sheet. The heated flexible sheet is an insulating film containing an inorganic compound.

[0006] According to one aspect of the present disclosure, an insulating film containing an inorganic compound can be formed on an uneven surface formed by a substrate and a plurality of dies.

[0007] FIG. 1 is a plan view showing a substrate processing system according to an embodiment. FIG. 2 is a flowchart showing a substrate processing method according to an embodiment. FIG. 3 is a cross-sectional view showing an example of step S101. FIG. 4 is a cross-sectional view showing an example of step S102. FIG. 5 is a cross-sectional view showing an example of step S104. FIG. 6 is a cross-sectional view showing an example of step S105. FIG. 7 is a cross-sectional view showing an example of step S106. FIG. 8 is a cross-sectional view showing an example of step S107.

[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 substrate processing system 101 according to one embodiment will be described with reference to Fig. 1. The substrate processing system 101 processes a die-attached substrate 10. As shown in Fig. 3, the die-attached substrate 10 has a substrate 20 and a plurality of dies 30 arranged at intervals on a main surface 20a of the substrate 20, and has an uneven surface 10a formed by the substrate 20 and the dies 30.

[0010] The substrate 20 includes, for example, a semiconductor substrate 21. In this embodiment, the semiconductor substrate 21 is a silicon wafer, but may also be a compound semiconductor wafer. The substrate 20 may also include an insulating film 22 formed on the semiconductor substrate 21. The insulating film 22 is formed, for example, by a chemical vapor deposition (CVD) method.

[0011] The insulating film 22 is, for example, a silicon oxide film. Silicon oxide films can be bonded together by hydrogen bonding between OH groups. After bonding, it is also possible to increase the bonding strength by a dehydration condensation reaction. Before bonding, the surface of the silicon oxide film may be activated with plasma, and then OH groups may be added to the surface by supplying water molecules. The silicon oxide film is formed using, for example, TEOS (Tetra Eth Oxy Silane).

[0012] An opening (not shown) may be provided in the insulating film 22, and an electrode may be provided in the opening. The electrode may electrically connect the electronic circuit of the substrate 20 to the electronic circuit of the die 30. Note that a conductive film (not shown) or the like may be provided between the semiconductor substrate 21 and the insulating film 22 as the electronic circuit of the substrate 20.

[0013] The die 30 has, for example, a semiconductor substrate 31. In this embodiment, the semiconductor substrate 31 is a silicon wafer, but it may also be a compound semiconductor wafer. The die 30 may have an insulating film 32 formed on the semiconductor substrate 31. The insulating film 32 is, for example, a silicon oxide film. The silicon oxide film is formed using, for example, TEOS.

[0014] The semiconductor substrate 31 may have a hole on the surface facing the substrate 20. An insulating film 32 may be formed on the bottom and side surfaces of the hole. An opening may be formed in the insulating film 32, and an electrode 33 may be provided in the opening. The electrode 33 may also be provided in the hole in the semiconductor substrate 31. The electrode 33 may electrically connect the electronic circuit of the die 30 and the electronic circuit of the substrate 20. Note that a conductive film (not shown) or the like may be provided between the semiconductor substrate 31 and the insulating film 32 as the electronic circuit of the die 30.

[0015] In this embodiment, the substrate 20 and the die 30 are inseparably bonded, but they may be bonded separably. In the latter case, the substrate 20 and the die 30 may be bonded with an adhesive. In the latter case, the bonding between the substrate 20 and the die 30 does not utilize hydrogen bonding between OH groups, so the insulating films 22 and 32 may be omitted.

[0016] As shown in FIG. 1, the substrate processing system 101 includes a loading / unloading station 110 , a processing station 120 , and a control circuit 190 .

[0017] The carry-in / out station 110 includes a mounting table 113. Cassettes C1 and C2 are placed on the mounting table 113. Cassette C1 stores the die-attached substrate 10 before processing. Cassette C2 stores the die-attached substrate 10 after processing. The number of cassettes C1 and C2 is not particularly limited. A cassette not shown may store a die-attached substrate 10 that has become defective during processing.

[0018] The carry-in / out station 110 includes a first transfer region 111 and a first transfer device 112. The first transfer region 111 is adjacent to the mounting table 113 and the transition device 123. The first transfer device 112 transfers the die-attached substrate 10 between multiple devices adjacent to the first transfer region 111. The first transfer device 112 has a transfer arm that holds the die-attached substrate 10 and a drive unit that moves or rotates the transfer arm. The transfer arm is capable of moving horizontally (in both the X-axis and Y-axis directions) and vertically, and of rotating about a vertical axis. Multiple transfer arms may be provided.

[0019] The processing station 120 includes a second transfer region 121, a second transfer device 122, a transition device 123, a laminating device 124, a heating device 125, a thinning device 126, an etching device 127, a film forming device 128, and a planarizing device 129. The arrangement and number of devices constituting the processing station 120 are not limited to those shown in FIG.

[0020] The second transfer region 121 is adjacent to a transition device 123, a laminating device 124, a heating device 125, a thinning device 126, an etching device 127, a film forming device 128, and a planarizing device 129. The second transfer device 122 transfers the die-attached substrate 10 between the multiple devices adjacent to the second transfer region 121. The second transfer device 122 has a transfer arm that holds the die-attached substrate 10 and a drive unit that moves or rotates the transfer arm. The transfer arm can move horizontally (in both the X-axis and Y-axis directions) and vertically, and can rotate about a vertical axis. Multiple transfer arms may be provided.

[0021] The transition device 123 temporarily stores the die-attached substrate 10. The transition device 123 is provided between the first transfer region 111 and the second transfer region 121, and relays the die-attached substrate 10 between the first transfer device 112 and the second transfer device 122.

[0022] As shown in FIG. 4 , the laminating device 124 laminates a flexible sheet 40 onto the uneven surface 10 a of the die-mounted substrate 10. The flexible sheet 40 deforms to conform to the convex and concave portions of the uneven surface 10 a. The flexible sheet 40 covers the top surfaces of the convex portions (the surfaces of the die 30 opposite the substrate 20), the side surfaces of the convex portions (the side surfaces of the die 30), and the bottom surfaces of the concave portions (the main surface 20 a of the substrate 20). Because the flexible sheet 40 is a solid, it hardly shrinks during lamination or heating. This prevents cracks caused by shrinkage. The flexible sheet 40 may be, for example, a material used for encapsulating semiconductors. Because materials used for encapsulating semiconductors require high heat dissipation, it is preferable for the thermal conductivity to be between 10 W / m·K and 250 W / m·K. The laminating device 124 preferably laminates the flexible sheet 40 onto the uneven surface 10a of the die-attached substrate 10 in a reduced pressure space that is lower than atmospheric pressure in order to prevent entrapment of air bubbles.

[0023] As shown in Fig. 4, when the laminating device 124 laminates the flexible sheet 40, the flexible sheet 40 may or may not completely fill the gaps between the dies 30 (it does not fill in Fig. 4). However, as shown in Fig. 8, after the planarizing device 129 planarizes the second insulating film 50, it is preferable that the second insulating film 50 and the insulating film formed by heating the flexible sheet 40 completely fill the gaps between the dies 30.

[0024] After the planarization device 129 planarizes the second insulating film 50, the height H of the die 30 is approximately 30 μm to 800 μm. Because the height H of the gap between the dies 30 is large, it is preferable to form the insulating film filling the gap using the flexible sheet 40 rather than using only the CVD method. This shortens the processing time.

[0025] The heating device 125 heats the flexible sheet 40 after the flexible sheet 40 has been laminated by the laminating device 124. Heating the flexible sheet 40 can improve the adhesion between the flexible sheet 40 and the die-attached substrate 10. The flexible sheet 40 heated by the heating device 125 is an insulating film containing an inorganic compound. The inorganic compound contains, for example, at least one of an oxide and a nitride. The inorganic compound preferably contains silicon oxide.

[0026] The heating device 125 can also heat the flexible sheet 40 to alter the flexible sheet 40. The alteration of the flexible sheet 40 includes, for example, at least one of pyrolysis, oxidation, and nitridation. The flexible sheet 40 only needs to contain an inorganic compound after being heated by the heating device 125, and may or may not contain an inorganic compound before being heated by the heating device 125.

[0027] Flexible sheet 40 preferably contains silicon (Si) before being heated by heating device 125. Silicon may be contained as an organosilicon compound such as a silicone resin. Flexible sheet 40 heated by heating device 125 is preferably an insulating film containing silicon oxide or silicon nitride.

[0028] The thinning device 126 thins the multiple dies 30 as shown in FIG. 5 after heating the flexible sheet 40 with the heating device 125. When the substrate 20 and the dies 30 are bonded, the dies 30 are easy to handle because of their large thickness. The thinning device 126 is, for example, a grinding device. The grinding device grinds the multiple dies 30 by rotating the die-mounted substrate 10 and a grinding wheel (not shown) and pressing the grinding wheel against the multiple dies 30. The grinding device also grinds the insulating film formed by heating the flexible sheet 40. The thinning device 126 may be a laser processing device.

[0029] After the die 30 is ground by the thinning device 126, the etching device 127 selectively etches the semiconductor substrate 31 relative to the electrodes 33, as shown in FIG. 6, to cause the electrodes 33 to protrude from the semiconductor substrate 31 on the side opposite to the substrate 20. The electrodes 33 are embedded in the semiconductor substrate 31 in advance. The electrodes 33 are protected by the insulating film 32 and are not etched. The etching includes, for example, plasma etching.

[0030] After the etching device 127 has caused the electrodes 33 to protrude, the film forming device 128 forms a second insulating film 50 on the electrodes 33 and the semiconductor substrate 31 as shown in FIG. 7. The second insulating film 50 is formed by, for example, a chemical vapor deposition (CVD) method. The second insulating film 50 is, for example, a silicon oxide film, and is formed using, for example, TEOS.

[0031] As shown in FIG. 8 , the planarization device 129 planarizes the second insulating film 50 to expose the electrode 33. The second insulating film 50 remains around the electrode 33. Planarization of the second insulating film 50 includes, for example, CMP (Chemical Mechanical Polishing). By planarizing the second insulating film 50 with a polishing machine, the electrode 33 is provided in the opening of the second insulating film 50. This allows a die (not shown) to be bonded on top of the die 30, and also allows the electronic circuit of the die 30 to be electrically connected to the electronic circuit of the die (not shown). After the planarization device 129 planarizes the second insulating film 50, it is preferable that the second insulating film 50 and the insulating film formed by heating the flexible sheet 40 completely fill the gap between the dies 30.

[0032] The control circuit 190 includes, for example, 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 substrate processing system 101. The control circuit 190 controls the operation of the substrate processing system 101 by causing the arithmetic unit 191 to execute the programs stored in the storage unit 192. An apparatus control circuit that controls the operation of each apparatus constituting the substrate processing system 101 may be provided, and a system control circuit that controls multiple apparatus control circuits may be provided. The control circuit 190 may be configured by the apparatus control circuits and the system control circuit.

[0033] The control circuit 190 includes electronic circuits such as a CPU, a GPU (Graphics Processing Unit), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit), and performs the various control operations described in this specification by executing instruction codes stored in memory or by being a circuit designed for a specific application.

[0034] Next, a substrate processing method according to one embodiment will be described with reference to FIG. 2. The substrate processing method includes, for example, steps S101 to S107. Steps S101 to S107 are performed under the control of the control circuit 190. Step S101 includes preparing a die-attached substrate 10. Step S101 includes, for example, loading a cassette C1 containing the die-attached substrate 10 into the substrate processing system 101.

[0035] First, the first transport device 112 takes out the die-attached substrate 10 from the cassette C1 and transports it to the transition device 123. Next, the second transport device 122 takes out the die-attached substrate 10 from the transition device 123 and transports it to the laminating device .

[0036] 4, the laminating device 124 laminates the flexible sheet 40 onto the uneven surface 10a of the die-attached substrate 10 (step S102). Thereafter, the second transport device 122 removes the die-attached substrate 10 from the laminating device 124 and transports it to the heating device 125.

[0037] Next, the heating device 125 heats the flexible sheet 40 (step S103). Heating the flexible sheet 40 can improve the adhesion between the flexible sheet 40 and the die-attached substrate 10. The heating device 125 can also alter the flexible sheet 40 by heating it. Thereafter, the second transport device 122 removes the die-attached substrate 10 from the heating device 125 and transports it to the thinning device 126.

[0038] 5, the thinning device 126 thins the plurality of dies 30 (step S104). After that, the second transfer device 122 removes the die-attached substrate 10 from the thinning device 126 and transfers it to the etching device 127.

[0039] Next, the etching device 127 selectively etches the semiconductor substrate 31 relative to the electrode 33, as shown in Figure 6, to cause the electrode 33 to protrude from the semiconductor substrate 31 on the side opposite to the substrate 20 (step S105). At this time, it is preferable to selectively etch the protrusions of the insulating film until the irregularities of the insulating film formed by heating the flexible sheet 40 become flat. Thereafter, the second transport device 122 removes the die-attached substrate 10 from the etching device 127 and transports it to the film forming device 128.

[0040] 7, the film forming device 128 forms a second insulating film 50 on the electrode 33 and the semiconductor substrate 31 (step S106). The second insulating film 50 may also be formed on an insulating film formed by heating the flexible sheet 40. Thereafter, the second transport device 122 removes the die-attached substrate 10 from the film forming device 128 and transports it to the planarization device 129.

[0041] Next, the planarization device 129 planarizes the second insulating film 50 as shown in FIG. 8 to expose the electrode 33 (step S107). The second insulating film 50 remains around the electrode 33. Planarization of the second insulating film 50 includes, for example, CMP (Chemical Mechanical Polishing). Thereafter, the second transfer device 122 removes the die-attached substrate 10 from the planarization device 129 and transfers it to the transition device 123.

[0042] Finally, the first transfer device 112 takes out the die-attached substrate 10 from the transition device 123 and stores it in the cassette C2. The die-attached substrate 10 stored in the cassette C2 is carried out from the substrate processing system 101.

[0043] Although the embodiments of the substrate processing method and substrate processing system 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.

[0044] This application claims priority based on Japanese Patent Application No. 2023-220440 filed with the Japan Patent Office on December 27, 2023, the entire contents of which are incorporated herein by reference.

[0045] 10: Substrate with die 10a: Textured surface 20: Substrate 20a: Main surface 30: Die

Claims

1. Prepare a substrate with dies having a concavo-convex surface formed by the substrate and a plurality of dies arranged at intervals on the main surface of the substrate, laminate a flexible sheet on the concavo-convex surface of the substrate with dies, and heat the flexible sheet after laminating the flexible sheet, wherein the heated flexible sheet is an insulating film containing an inorganic compound, a substrate processing method.

2. The substrate processing method according to claim 1, wherein the insulating film contains at least one of an oxide and a nitride as the inorganic compound.

3. The substrate processing method according to claim 2, wherein the insulating film contains silicon oxide as the inorganic compound.

4. The substrate processing method according to any one of claims 1 to 3, further comprising thinning a plurality of the dies after heating the flexible sheet.

5. The die has a semiconductor substrate and an electrode embedded in the semiconductor substrate. Thinning the die includes thinning the semiconductor substrate of the die. The substrate processing method includes, after thinning the semiconductor substrate of the die, selectively etching the semiconductor substrate compared to the electrode to project the electrode to the side opposite to the substrate from the semiconductor substrate, forming a second insulating film on the electrode and the semiconductor substrate after projecting the electrode, and exposing the electrode by planarizing the second insulating film. The substrate processing method according to claim 4.

6. A substrate processing system for processing a substrate with dies having a concavo-convex surface formed by the substrate and a plurality of dies arranged at intervals on the main surface of the substrate, the system comprising a laminating device for laminating a flexible sheet on the concavo-convex surface of the substrate with dies, and a heating device for heating the flexible sheet after laminating the flexible sheet by the laminating device, wherein the flexible sheet heated by the heating device is an insulating film containing an inorganic compound, a substrate processing system.

7. The substrate processing system according to claim 6, wherein the insulating film contains at least one of an oxide and a nitride as the inorganic compound.

8. The substrate processing system according to claim 7, wherein the insulating film contains silicon oxide as the inorganic compound.

9. The substrate processing system according to any one of claims 6 to 8, further comprising a thinning device that thins a plurality of the dies after heating the flexible sheet with the heating device.

10. The die has a semiconductor substrate and electrodes embedded in the semiconductor substrate. The thinning device thins the semiconductor substrate of the die. After thinning the semiconductor substrate of the die with the thinning device, the substrate processing system includes an etching device that selectively etches the semiconductor substrate compared to the electrodes to project the electrodes from the semiconductor substrate to the side opposite to the substrate, a film forming device that forms a second insulating film on the electrodes and the semiconductor substrate after projecting the electrodes with the etching device, and a planarizing device that exposes the electrodes by planarizing the second insulating film. The substrate processing system according to claim 9.

Images