Substrate processing method and substrate processing system

Abstract

A substrate processing method comprises grinding a first substrate of a laminated substrate that includes the first substrate, a second substrate affixed to the first substrate, and an intermediate layer provided between the first substrate and the second substrate. The substrate processing method also comprises: acquiring position information pertaining to the radially inner end of a first region in which the thickness of the laminated substrate decreases from the radially inner side of the laminated substrate toward the radially outer side thereof before the grinding of the first substrate; and measuring the thickness of the first substrate, after the grinding of the first substrate, in a circular second region set away from the radially inner end of the first region toward the radially inner side by at least a set distance.

Description

Substrate processing method and substrate processing system

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

[0002] The grinding apparatus described in Patent Document 1 grinds a laminated substrate. The laminated substrate has a first substrate and a second substrate bonded to the first substrate. The first substrate has a first base substrate and a first device layer formed on the surface of the first base substrate facing the second substrate. The second substrate has a second base substrate and a second device layer formed on the surface of the second base substrate facing the first substrate.

[0003] The grinding apparatus described in Patent Document 1 grinds a first base substrate with a grinding tool. After grinding the first base substrate, the grinding apparatus measures the radial thickness distribution of the first base substrate and calculates a correction value for the tilt of the rotation center line of the holder based on the measurement results. The correction value is calculated so as to minimize the total thickness variation (TTV) of the first base substrate after grinding. The correction value is taken into account when grinding the first base substrate next and thereafter.

[0004] Japanese Patent Application Publication No. 2021-118300

[0005] One embodiment of the present disclosure provides a technique that can measure the thickness of a first substrate, which is bonded to a second substrate via an intermediate layer, after grinding the first substrate without introducing noise due to edge roll-off of the intermediate layer.

[0006] A substrate processing method according to an embodiment of the present disclosure includes grinding a first substrate of a bonded substrate including a first substrate, a second substrate bonded to the first substrate, and an intermediate layer provided between the first substrate and the second substrate, the substrate processing method including: acquiring positional information of a radially inner end of a first region of the bonded substrate before grinding the first substrate, the first region being a region in which the thickness of the bonded substrate decreases from the radially inner side toward the radially outer side of the bonded substrate; and measuring the thickness of the first substrate after grinding in a circular second region that is at least a set distance radially inward from the radially inner end of the first region.

[0007] According to one embodiment of the present disclosure, after grinding a first substrate bonded to a second substrate via an intermediate layer, the thickness of the first substrate can be measured without introducing noise due to edge roll-off of the intermediate layer.

[0008] FIG. 1(A) is a cross-sectional view showing a first substrate and a second substrate before bonding according to a reference example, FIG. 1(B) is a cross-sectional view showing a bonded substrate before grinding of the first substrate according to a reference example, and FIG. 1(C) is a cross-sectional view showing a bonded substrate after grinding of the first substrate according to a reference example. FIG. 2(A) is a cross-sectional view showing a first substrate and a second substrate before bonding according to an example, FIG. 2(B) is a cross-sectional view showing a bonded substrate before grinding of the first substrate according to an example, and FIG. 2(C) is a cross-sectional view showing a bonded substrate after grinding of the first substrate according to an example. FIG. 3 is a plan view showing a substrate processing system according to an example. FIG. 4 is a side view showing an example of a drive unit of a grinding device. FIG. 5 is a plan view showing an example of a measurement unit. FIG. 6 is a cross-sectional view showing an example of a measurement unit. FIG. 7 is a flowchart showing an example of a substrate processing method. FIG. 8 is a flowchart showing another example of a substrate processing method. FIG. 9 is a flowchart showing yet another example of a substrate processing method.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, identical or similar components are denoted by the same reference numerals, and descriptions thereof may be omitted. In each drawing, the X-axis, Y-axis, and Z-axis directions are perpendicular to each other, the X-axis and Y-axis directions are horizontal, and the Z-axis direction is vertical.

[0010] The X-axis direction includes the positive X-axis direction and the negative X-axis direction opposite to the positive X-axis direction. The Y-axis direction includes the positive Y-axis direction and the negative Y-axis direction opposite to the positive Y-axis direction. The Z-axis direction includes the positive Z-axis direction and the negative Z-axis direction opposite to the positive Z-axis direction.

[0011] A technology has been developed in which a bonded substrate WT is produced by bonding a first substrate W1 and a second substrate W2 together via intermediate layers W3 and W4, as shown in Figures 1(A) and 1(B), and then thinning the first substrate W1 by grinding it, as shown in Figure 1(C). The bonded substrate WT includes a first substrate W1, a second substrate W2 bonded to the first substrate W1, and intermediate layers W3 and W4 provided between the first substrate W1 and the second substrate W2. The intermediate layer W3 is formed on the first substrate W1 before bonding. The intermediate layer W4 is formed on the second substrate W2 before bonding.

[0012] The bonded substrate WT is composed of a first substrate W1 and a remainder WR excluding the first substrate W1. The remainder WR includes a second substrate W2 and intermediate layers W3 and W4. The thickness HT of the bonded substrate WT is equal to the sum of the thickness H1 of the first substrate W1 and the thickness HR of the remainder WR. The thickness HR of the remainder WR is equal to the sum of the thickness H2 of the second substrate W2, the thickness H3 of the intermediate layer W3, and the thickness H4 of the intermediate layer W4.

[0013] The first substrate W1 and the second substrate W2 are each a semiconductor substrate, a glass substrate, or the like. The semiconductor substrate is a silicon wafer, a compound semiconductor wafer, or the like. The first substrate W1 and the second substrate W2 are bonded together via intermediate layers W3 and W4. The intermediate layer W3 is formed on the surface of the first substrate W1 facing the second substrate W2. The intermediate layer W3 has, for example, a device layer and a bonding layer. The device layer and the bonding layer are formed in this order on the first substrate W1. The device layer includes electronic circuits, etc., and includes a metal layer. The bonding layer is an oxide layer such as a silicon oxide layer, or a nitride layer, or the like.

[0014] The intermediate layer W4 is formed on the surface of the second substrate W2 facing the first substrate W1. The intermediate layer W4 has, for example, a device layer and a bonding layer. The device layer and bonding layer are formed on the second substrate W2 in this order. The device layer includes electronic circuits and the like and also includes a metal layer. The bonding layer is an oxide layer such as a silicon oxide layer, or a nitride layer. Unlike the intermediate layer W3, the intermediate layer W4 only needs to include a bonding layer and does not necessarily need to include a device layer.

[0015] 4, the grinding apparatus 10 grinds the first substrate W1 with a grinding tool T. The grinding apparatus 10 has holding units 11A to 11D that hold the bonded substrate WT, driving units 12A to 12C that drive the grinding tool T, a rotation unit 17 that rotates the bonded substrate WT together with the holding units 11A to 11D, and an adjustment unit 18 that adjusts the inclination of the rotation center line R2 of the holding units 11A to 11D.

[0016] The inclination of the rotation center line R2 of the holding parts 11A to 11D is the inclination of the rotation center line R2 of the holding parts 11A to 11D relative to the rotation center line R3 of the grinding tool T. The rotation center line R3 of the grinding tool T is usually set vertically. Therefore, the inclination of the rotation center line R2 of the holding parts 11A to 11D may be the inclination of the rotation center line R2 of the holding parts 11A to 11D relative to a vertical line.

[0017] The control circuit 90 (see FIG. 3) controls the inclination of the rotation center line R2 of the holders 11A-11D during grinding of the first substrate W1 based on the radial thickness distribution (distribution of thickness HR) of the remaining portion WR of the bonded substrate WT before grinding of the first substrate W1, thereby reducing the total thickness variation (TTV) of the thickness H1 of the first substrate W1 after grinding of the first substrate W1.

[0018] In order to further reduce variations in the thickness H1 of the first substrate W1 after grinding, the grinding apparatus 10 preferably measures the radial thickness distribution (distribution of thickness H1) of the first substrate W1 after grinding the first substrate W1. Based on the measurement results, a correction value for the tilt of the rotation center line R2 of the holders 11A to 11D can be calculated.

[0019] The correction value is calculated so as to minimize the variation in the thickness H1 of the first substrate W1 after grinding. The calculated correction value is used when grinding the first substrate W1 from the next time onwards. When grinding the first substrate W1 from the next time onwards, the tilt can be controlled taking into account error factors such as the characteristics of the grinding apparatus 10.

[0020] As shown in FIG. 2A , the intermediate layer W3 may have a third region WC along the entire outer periphery of the intermediate layer W3, in which the thickness H3 of the intermediate layer W3 decreases from the radially inner side toward the radially outer side of the intermediate layer W3. The third region WC is a region generally referred to as an edge roll-off. The edge roll-off of the intermediate layer W3 exists in a region where the thickness H1 of the first substrate W1 is constant. Incidentally, an example of a region where the thickness H1 of the first substrate W1 is not constant is a region where chamfering is performed (not shown). The edge roll-off exists radially inward of the region where chamfering is performed.

[0021] Similarly, the intermediate layer W4 may have a fourth region WD along the entire outer periphery of the intermediate layer W4, in which the thickness H4 of the intermediate layer W4 decreases from the radially inner side toward the radially outer side of the intermediate layer W4. The fourth region WD is a region generally referred to as an edge roll-off. The edge roll-off of the intermediate layer W4 exists in a region where the thickness H2 of the second substrate W2 is constant. Incidentally, an example of a region where the thickness H2 of the second substrate W2 is not constant is a region where chamfering is performed (not shown). The edge roll-off exists radially inside the region where chamfering is performed.

[0022] When the first substrate W1 and the second substrate W2 are bonded together via the intermediate layers W3 and W4, the third region WC and the fourth region WD may at least partially overlap. If the intermediate layer W4 has only a bonding layer and no device layer, the intermediate layer W4 does not need to have edge roll-off. Incidentally, when the first substrate W1 and the second substrate W2 are bonded together via the intermediate layers W3 and W4, the first region WA, which will be described later, is a region that overlaps with at least one of the third region WC and the fourth region WD.

[0023] When the first substrate W1 and the second substrate W2 are bonded together via the intermediate layer W3, the bonded substrate WT may have a first region WA resulting from edge roll-off of the intermediate layer W3 or W4, as shown in Fig. 2(B). The first region WA exists along the entire outer periphery of the bonded substrate WT. In the first region WA, the thickness HT of the bonded substrate WT becomes thinner from the radially inner side to the radially outer side of the bonded substrate WT.

[0024] A circular second region WB is set in the bonded substrate WT, the second region WB being at least a set distance D radially inward from the radially inner end WA1 of the first region WA. In the second region WB, the total thickness (H3+H4) of the intermediate layer W3 and the intermediate layer W4 is substantially constant, and therefore the thickness HT of the bonded substrate WT is substantially constant. The fluctuation range of HT in the second region WB is negligibly small compared to the fluctuation range of HT in the first region WA, for example, 1 / 10 or less of the fluctuation range of HT in the first region WA.

[0025] The radially inner end WA1 of the first region WA and the second region WB are concentric. The center of the radially inner end WA1 of the first region WA and the center of the second region WB coincide with the center of the bonded substrate WT. A set distance D between the radially inner end WA1 of the first region WA and the radially outer end WB1 of the second region WB is set, for example, according to the measurement resolution of the second measurement device 2 described below. The set distance D is not particularly limited, but is, for example, 1 mm to 5 mm.

[0026] 2C , after grinding the first substrate W1, the thickness H1 of the first substrate W1 may increase from the radially inner side to the radially outer side in the first region WA. This variation in H1 is caused by edge roll-off of the intermediate layer W3 or the intermediate layer W4. The total thickness (H3 + H4) of the intermediate layer W3 and the intermediate layer W4 decreases from the radially inner side to the radially outer side in the first region WA, and the thickness H1 of the first substrate W1 increases accordingly.

[0027] As described above, the correction value for the tilt of the rotation center line R2 of the holders 11A to 11D is calculated so as to minimize the variation in the thickness H1 of the first substrate W1 after grinding. In the process of calculating the correction value, it is preferable to ignore the variation in the thickness H1 of the first substrate W1 in the first area WA.

[0028] If the variation in the thickness H1 of the first substrate W1 in the first region WA is ignored, the variation in the thickness H1 of the first substrate W1 in the second region WB can be reduced after the first substrate W1 is ground, compared to when the variation is not ignored. As a result, the quality of the dies obtained from the second region WB can be stabilized. The dies are obtained by dicing the bonded substrate WT.

[0029] A substrate processing system 1 according to one embodiment will be described mainly with reference to FIG. 3 . As shown in FIG. 3 , the substrate processing system 1 includes a grinding apparatus 10, a measuring apparatus 20, a correction processing apparatus 30, and a transport apparatus 40. As shown in FIG. 4 , the grinding apparatus 10 grinds the first substrate W1 of the bonded substrate WT by pressing a grinding tool T against the first substrate W1. In this specification, grinding includes polishing. The measuring apparatus 20 measures the thickness H1 of the first substrate W1. After grinding the first substrate W1, the correction processing apparatus 30 performs correction processing on the first substrate W1 to correct the thickness H1 of the first substrate W1. The correction processing apparatus 30 is an optional configuration and may be absent. If the correction processing apparatus 30 is not present, the correction processing of the first substrate W1 may be performed outside the substrate processing system 1. The transport apparatus 40 transports the bonded substrate WT.

[0030] The grinding apparatus 10 includes, for example, four holding units 11A to 11D, three driving units 12A to 12C, and a housing 13. The holding units 11A to 11D hold the bonded substrate WT. Holding includes suction. The driving units 12A to 12C drive the grinding tool T. The housing 13 houses the holding units 11A to 11D and the grinding tool T. The housing 13 prevents particles and mist generated during grinding from escaping to the outside. The housing 13 has a carry-in / out opening 13a. The bonded substrate WT is carried in from the outside to the inside of the housing 13 or carried out from the inside of the housing 13 to the outside through the carry-in / out opening 13a.

[0031] The grinding device 10 may include a rotary table 15 as shown in FIG. 3. The rotary table 15 is provided inside the housing 13. The rotary table 15 is rotated around a rotation center line R1. The four holders 11A to 11D are provided at intervals around the rotation center line R1 of the rotary table 15 and are rotated together with the rotary table 15. Furthermore, the four holders 11A to 11D are rotated independently around their respective rotation center lines R2 (see FIG. 4).

[0032] The four holders 11A to 11D are arranged at equal intervals around the rotation center line R1 of the turntable 15. Each of the four holders 11A to 11D rotates together with the turntable 15 and moves, for example, to a load / unload position A0, a first grinding position A1, a second grinding position A2, a third grinding position A3, and the load / unload position A0 in this order. The load / unload position A0 serves as both a load position where the transport device 40 hands over the bonded substrate WT to each of the holders 11A to 11D and a load / unload position where the transport device 40 receives the bonded substrate WT from each of the holders 11A to 11D. Note that the load / unload positions may be different positions. The first grinding position A1 is a position where primary grinding of the first substrate W1 is performed. The second grinding position A2 is a position where secondary grinding of the first substrate W1 is performed. The third grinding position A3 is a position where the tertiary grinding of the first substrate W1 is carried out.

[0033] The number of holding units is not limited to four. The number of driving units is not limited to three. Therefore, the number of grinding positions is not limited to three. The rotary table 15 may be omitted. A slide table may be provided instead of the rotary table 15.

[0034] The measuring device 20 measures the thickness H1 of the first substrate W1. The measuring device 20 may be provided at the carry-in / out position A0 as shown in Fig. 3, or may be provided at the third grinding position A3 (not shown). The measuring device 20 measures the thickness H1 of the first substrate W1 after the tertiary grinding at the carry-in / out position A0 or the third grinding position A3.

[0035] The installation position of the measuring device 20 is not particularly limited. The measuring device 20 may be installed at the first grinding position A1 or the second grinding position A2, and measure the thickness H1 of the first substrate W1 after the primary grinding or the secondary grinding. The measuring device 20 is installed inside the housing 13 of the grinding apparatus 10, but may also be installed outside the housing 13.

[0036] The transport device 40 includes a transport arm 41 that transports the bonded substrate WT. The transport arm 41 includes a suction pad 42 that adsorbs the bonded substrate WT. The suction pad 42 is capable of moving horizontally (in both the X-axis direction and the Y-axis direction) and vertically, and of rotating about a vertical axis. The transport arm 41 transports the bonded substrate WT between a plurality of devices. Examples of devices into and out of which the transport arm 41 transports the bonded substrate WT include a substrate accommodation device and a substrate cleaning device. The substrate accommodation device accommodates the bonded substrate WT. The substrate cleaning device cleans the bonded substrate WT.

[0037] The substrate processing system 1 includes a control circuit 90. The control circuit 90 is, for example, a computer. The control circuit 90 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 substrate processing system 1. The control circuit 90 controls the operation of the substrate processing system 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92. A lower-level control circuit that controls the operation of each device that makes up the substrate processing system 1 may be provided, and a higher-level control circuit that controls multiple lower-level control circuits may be provided. The control circuit 90 may be configured with the lower-level control circuit and the higher-level control circuit.

[0038] The program, i.e., a computer program product, may be supplied in a form recorded on a removable storage medium such as a memory card, an optical disk, or a hard disk drive (HDD). The control circuit 90 reads the program from the storage medium and stores it in the storage unit 92. The storage unit 92 includes a storage medium such as an HDD, a solid state drive (SDD), or an electronically erasable programmable read-only memory (EEPROM). The program may be written in advance to the storage medium of the storage unit 92. The control circuit 90 may also obtain the program distributed by a remote server device or the like via a network or other communication.

[0039] The control circuit 90 includes electronic circuits such as a CPU, a graphics processing unit (GPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC). The control circuit 90 executes various control operations described in this specification by executing instruction codes stored in a storage medium such as a memory, or by being a circuit designed for a specific application.

[0040] An example of the operation of the substrate processing system 1 shown in Fig. 3 will be described. The following operation is performed under the control of the control circuit 90. First, the transport device 40 transports the bonded substrate WT to a holder (e.g., holder 11D) located at the load / unload position A0. The holder 11D holds the bonded substrate WT from below with the first substrate W1 facing upward. Thereafter, the turntable 15 is rotated 90° counterclockwise, and the holder 11D is moved from the load / unload position A0 to the first grinding position A1.

[0041] Next, the driver 12A drives the grinding tool T to perform the primary grinding of the first substrate W1. Thereafter, the turntable 15 is rotated 90° counterclockwise, and the holder 11D is moved from the first grinding position A1 to the second grinding position A2. Thereafter, the driver 12B drives the grinding tool T to perform the secondary grinding of the first substrate W1. Thereafter, the turntable 15 is rotated 90° counterclockwise, and the holder 11D is moved from the second grinding position A2 to the third grinding position A3. Thereafter, the driver 12C drives the grinding tool T to perform the tertiary grinding of the first substrate W1.

[0042] Thereafter, the turntable 15 is rotated clockwise by 270°, and the holder 11D is moved from the third grinding position A3 to the carry-in / out position A0. At the carry-in / out position A0, the bonded substrate WT is cleaned, the thickness H1 of the first substrate W1 is measured, and the bonded substrate WT is carried out, in this order. Thereafter, at the carry-in / out position A0, the holding surfaces (upper surfaces) of the holders 11A, 11B, 11C, or 11D are cleaned, and the bonded substrate WT is carried in, in this order.

[0043] Here, the operation of the substrate processing system 1 has been described with a focus on one bonded substrate WT. The substrate processing system 1 may simultaneously perform multiple processes at multiple positions to improve throughput. For example, the substrate processing system 1 simultaneously grinds the first substrate W1 of the bonded substrate WT at each of the first grinding position A1, the second grinding position A2, and the third grinding position A3. Meanwhile, the substrate processing system 1 performs, in this order, cleaning of the bonded substrate WT, measuring the thickness H1 of the first substrate W1, unloading the bonded substrate WT, cleaning the holding surface (upper surface) of the holder 11A, 11B, 11C, or 11D, and loading of the bonded substrate WT, for example, at the load / unload position A0.

[0044] An example of the grinding apparatus 10 will be described again with reference to Fig. 4. The grinding apparatus 10 grinds the first substrate W1 of the bonded substrate WT by pressing a grinding tool T against the first substrate W1. The grinding tool T includes, for example, a disk-shaped grinding wheel T1 and a plurality of grinding stones T2 arranged in a ring shape on the underside of the grinding wheel T1. The grinding stones T2 grind the first substrate W1.

[0045] The grinding apparatus 10 includes holding units 11A to 11D. The holding units 11A to 11D have a holding surface 111 on the upper surface that holds the bonded substrate WT. The holding units 11A to 11D hold the bonded substrate WT from the side opposite to the grinding tool T (i.e., the lower side). The holding units 11A to 11D are, for example, vacuum chucks. The holding surface 111 is preferably a conical surface in order to adjust the distribution of the thickness H1 of the first substrate W1 after grinding.

[0046] The grinding device 10 includes driving units 12A to 12C. The driving units 12A to 12C drive the grinding tool T. The driving units 12A to 12C each include, for example, a rotating unit 121 and an elevating unit 125. The rotating unit 121 holds and rotates the grinding tool T. The elevating unit 125 elevates the grinding tool T together with the rotating unit 121.

[0047] The rotating unit 121 has, for example, a rotary motor 122, a vertical spindle shaft 123 rotated by the rotary motor 122, and a flange 124 provided at the lower end of the spindle shaft 123. The flange 124 is disposed horizontally, and a grinding tool T is attached to its lower surface. The rotary motor 122 rotates the spindle shaft 123, thereby rotating the grinding tool T attached to the lower surface of the flange 124. The rotation center line R3 of the grinding tool T is the rotation center line of the spindle shaft 123.

[0048] The lifting unit 125 has, for example, a vertical Z-axis guide 126, a Z-axis slider 127 that moves along the Z-axis guide 126, and an elevator motor 128 that moves the Z-axis slider 127. The rotary motor 122 is fixed to the Z-axis slider 127 via a motor holder 129. The lifting unit 125 has a ball screw (not shown) that converts the rotational motion of the elevator motor 128 into linear motion of the Z-axis slider 127.

[0049] The grinding device 10 includes a rotating unit 17. The rotating unit 17 has, for example, a rotary motor 171 and a vertical rotary shaft 172 that is rotated by the rotary motor 171. The holding units 11A to 11D are provided at the upper end of the rotary shaft 172. The number of rotating units 17 may be the same as the number of holding units 11A to 11D. The multiple rotating units 17 individually rotate the multiple holding units 11A to 11D.

[0050] The rotary motor 171 rotates the holders 11A to 11D together with the rotary shaft 172. The rotation center line R2 of the holders 11A to 11D is the rotation center line of the rotary shaft 172. The rotary shaft 172 is preferably inclined with respect to the rotation center line R3 of the grinding tool T in order to adjust the distribution of the thickness H1 of the first substrate W1 after grinding.

[0051] The grinding device 10 includes an adjustment unit 18. The adjustment unit 18 adjusts the inclination of the rotation center line R2 of the holding units 11A to 11D. The adjustment unit 18 may have a general configuration. The number of adjustment units 18 may be the same as the number of holding units 11A to 11D. The multiple adjustment units 18 individually adjust the inclination of the rotation center line R2 of the multiple holding units 11A to 11D.

[0052] An example of the measuring device 20 will be described with reference to Figures 5 and 6. The grinding device 10 is equipped with the measuring device 20. The measuring device 20 irradiates light onto the bonded substrate WT held by the holding units 11A to 11D. The measuring device 20 has, for example, a laser displacement meter. The laser displacement meter is, for example, of a spectral interference type or a confocal type.

[0053] The measuring device 20 receives light reflected by the reflecting surface of the bonded substrate WT to measure the height of the reflecting surface of the bonded substrate WT. The measuring device 20 irradiates the bonded substrate WT with light from above and receives light reflected by the upper surface of the first substrate W1 and the lower surface of the first substrate W1 to measure the height difference between the upper and lower surfaces of the first substrate W1, i.e., the thickness H1 of the first substrate W1.

[0054] The measuring device 20 has an irradiation head 21. The irradiation head 21 irradiates the bonded substrate WT with light. The irradiation head 21 has an optical system (not shown) and a housing that houses the optical system. The optical system includes, for example, a mirror.

[0055] The measuring device 20 may include a moving mechanism 22. The moving mechanism 22 is an actuator. The moving mechanism 22 moves the irradiation head 21 in the horizontal direction. The moving mechanism 22 moves the irradiation head 21 between directly above the center of the bonded substrate WT and directly above the periphery of the bonded substrate WT, thereby making it possible to measure the thickness H1 of the first substrate W1 over the entire radial direction of the bonded substrate WT. The moving mechanism 22 may move the irradiation head 21 in the horizontal and vertical directions.

[0056] The movement mechanism 22 has, for example, a swivel arm 221, a swivel shaft 222, and a drive source 223. The irradiation head 21 is provided on the swivel arm 221. The drive source 223 rotates the swivel arm 221 about the swivel shaft 222, thereby rotating the irradiation head 21 about the swivel shaft 222. The drive source 223 may raise and lower the swivel shaft 222, thereby raising and lowering the irradiation head 21.

[0057] Although not shown, the movement mechanism 22 may have a guide, a slider, and a drive source. In this case, the irradiation head 21 is provided on the slider. The drive source moves the slider along the guide, thereby moving the irradiation head 21 along the guide. A set of a guide, a slider, and a drive source is provided for each movement direction of the irradiation head 21.

[0058] An example of the substrate processing method will be described with reference to Fig. 7. The substrate processing method includes, for example, steps S101 to S103. Steps S101 to S103 are performed under the control of the control circuit 90.

[0059] Step S101 includes the control circuit 90 acquiring position information of the radially inner end WA1 of the first area WA. The control circuit 90 acquires the position information of the radially inner end WA1 of the first area WA by acquiring measurement data of the second measurement device 2 shown in FIG. 3, for example. In this embodiment, the second measurement device 2 is provided outside the substrate processing system 1, but may also be provided inside the substrate processing system 1.

[0060] The second measuring device 2 measures the thickness HT of the bonded substrate WT, for example, after the first substrate W1 and the second substrate W2 are bonded together and before the first substrate W1 is ground. The thickness distribution of the bonded substrate WT tends to vary little in the circumferential direction of the bonded substrate WT but varies in the radial direction of the bonded substrate WT. Therefore, the thickness HT of the bonded substrate WT is measured at multiple measurement points that are different distances from the center of the bonded substrate WT. The second measuring device 2 may be of a contact type or a non-contact type.

[0061] The control circuit 90 acquires the position of the radial inner end WA1 of the first area WA by acquiring the measurement results of the second measurement device 2. Furthermore, the control circuit 90 can also acquire the thickness distribution (distribution of thickness HT) in the radial direction of the bonded substrate WT in the first area WA by acquiring the measurement results of the second measurement device 2, which will be used in step S106 of Fig. 9 described later.

[0062] 2(B), before the first substrate W1 is ground, the radial thickness distribution of the bonded substrate WT (distribution of thickness HT) has the same tendency as the radial thickness distribution of the intermediate layers W3 and W4 (distribution of total thickness (H3+H4)). Therefore, the second measuring device 2 may measure the radial thickness distribution of the intermediate layers W3 and W4 (distribution of total thickness (H3+H4)). The thicknesses H3 and H4 can be measured before the first substrate W1 and the second substrate W2 are bonded together. The distribution of thickness HT after bonding can be determined from the distributions of thicknesses H3 and H4 before bonding.

[0063] 2C , after grinding the first substrate W1, the thickness H1 of the first substrate W1 may increase from the radially inner side to the radially outer side in the first region WA. This variation in H1 is caused by edge roll-off of the intermediate layer W3 or the intermediate layer W4. The total thickness (H3 + H4) of the intermediate layer W3 and the intermediate layer W4 decreases from the radially inner side to the radially outer side in the first region WA, and the thickness H1 of the first substrate W1 increases accordingly.

[0064] Step S102 includes measuring the thickness H1 of the first substrate W1 after grinding in the second region WB by the measuring device 20. The thickness H1 of the first substrate W1 is not measured in the first region WA. This allows the thickness H1 of the first substrate W1 to be measured without noise caused by edge roll-off of the intermediate layer W3 or W4.

[0065] When step S103 is performed following step S102, multiple measurement points for H1 are set in step S102. The multiple measurement points are at different distances from the center of the first substrate W1. One measurement point is set at the radial outer edge WB1 of the second region WB. Another measurement point is preferably set at a position within 10 mm from the center of the second region WB. The thickness distribution (distribution of thickness H1) of the first substrate W1 can be measured over the entire radial direction of the second region WB. Some of the multiple measurement points may be at the same distance from the center of the first substrate W1. The average or median value of H1 measured at multiple measurement points at the same distance from the center of the first substrate W1 may be used as a representative value to measure the thickness distribution (distribution of thickness H1) of the first substrate W1 in the radial direction of the second region WB.

[0066] Step S103 includes the control circuit 90 calculating a correction value for the tilt of the rotation center line R2 of the holders 11A-11D based on the radial thickness distribution (distribution of thickness H1) of the first substrate W1 in the second region WB after the first substrate W1 has been ground. This correction value is, for example, a value that is expected to minimize variation in the thickness H1 of the first substrate W1 after the current grinding of the first substrate W1 if that correction value had been used. The tilt correction value is calculated individually for each of the holders 11A-11D.

[0067] In step S103, the variation in the thickness H1 of the first substrate W1 in the first area WA is ignored. Compared to when the variation is not ignored, the variation in the thickness H1 of the first substrate W1 in the second area WB after grinding the first substrate W1 can be reduced from the next time onwards. As a result, the quality of the dies obtained by dicing the bonded substrate WT in the second area WB can be stabilized.

[0068] The correction value calculated in step S103 is used when grinding the next and subsequent first substrates W1. The control circuit 90 controls the inclination of the rotation center line R2 of the holders 11A to 11D when grinding the (n+1)th and subsequent first substrates W1, based on the radial thickness distribution (distribution of thickness H1) of the first substrate W1 in the second region WB after grinding the nth first substrate W1.

[0069] The inclination of the rotation center line R2 of each of the holding units 11A to 11D is controlled individually for each of the holding units 11A to 11D. n is counted for each of the holding units 11A to 11D. The correction value calculated in step S103 only needs to be used at the finish grinding position (e.g., the third grinding position A3), and does not need to be used at the pre-grinding positions (e.g., the first grinding position A1 and the second grinding position A2). At the pre-grinding position, the inclination of the rotation center line R2 of each of the holding units 11A to 11D may be the same for the (n+1)th piece and the nth piece.

[0070] Another example of the substrate processing method will be described with reference to Fig. 8. The substrate processing method includes, for example, steps S101 to S102 and S104 to S105. Steps S101 to S102 and S104 to S105 are performed under the control of the control circuit 90. It is also possible to combine steps S104 to S105 shown in Fig. 8 with step S103 shown in Fig. 7. Steps S104 to S105 will be described below.

[0071] Step S104 includes measuring the thickness distribution (distribution of thickness H1) in the radial direction of the first substrate W1 in the first region WA after grinding the first substrate W1 by the measuring device 20. In step S104, H1 is measured at a plurality of measurement points that are different distances from the center of the first substrate W1.

[0072] 2C, after grinding the first substrate W1, the thickness H1 of the first substrate W1 may increase from the radially inner side to the radially outer side in the first region WA. This variation in H1 is caused by edge roll-off of the intermediate layer W3 or W4, and can be grasped in step S104.

[0073] Step S105 includes the correction processing device 30 performing correction processing on the first substrate W1 based on the thickness distribution (distribution of thickness H1) measured by the measuring device 20 in step S104. After the first substrate W1 is ground, the correction processing device 30 corrects the thickness of the first substrate W1 so that the difference in thickness of the first substrate W1 between the first area WA and the second area WB is reduced. This improves the quality of the dies obtained from the first area WA to the same level as the quality of the dies obtained from the second area WB.

[0074] The correction processing device 30 removes the surface of the first substrate W1 in at least the first region WA. The amount of removal preferably increases radially outward from the radial inner end WA1 of the first region WA. This can reduce variations in the thickness H1 of the first substrate W1 due to edge roll-off of the intermediate layer W3 or W4.

[0075] The correction processing device 30 may grind the surface of the first substrate W1 not only in the first area WA but also in the second area WB. The correction processing device 30 may correct the thickness of the first substrate W1 so that the difference in thickness of the first substrate W1 between the first area WA and the second area WB becomes smaller. The correction processing device 30 is not particularly limited, but may be, for example, an etching device or a polishing device.

[0076] Another example of the substrate processing method will be described with reference to Fig. 9. The substrate processing method includes, for example, steps S101 to S102 and S106 to S108. Steps S101 to S102 and S106 to S108 are performed under the control of the control circuit 90. It is also possible to combine steps S106 to S108 shown in Fig. 9 with step S103 shown in Fig. 7. Steps S106 to S108 will be described below.

[0077] In step S106, the control circuit 90 acquires information on the radial thickness distribution (distribution of thickness HT) of the bonded substrate WT in the first area WA before grinding of the first substrate W1. The control circuit 90 acquires the distribution of HT in the first area WA by acquiring measurement data from the second measuring device 2 shown in Fig. 1, for example. As shown in Fig. 2(B), before grinding of the first substrate W1, the distribution of HT has the same tendency as the distribution of (H3 + H4).

[0078] 2C , after grinding the first substrate W1, the thickness H1 of the first substrate W1 may increase from the radially inner side to the radially outer side in the first region WA. This variation in H1 is caused by edge roll-off of the intermediate layer W3 or the intermediate layer W4. The total thickness (H3 + H4) of the intermediate layer W3 and the intermediate layer W4 decreases from the radially inner side to the radially outer side in the first region WA, and the thickness H1 of the first substrate W1 increases accordingly.

[0079] Step S107 includes the control circuit 90 predicting the radial thickness distribution (distribution of thickness H1) of the first substrate W1 in the first area WA after grinding the first substrate W1 based on the thickness distribution (distribution of thickness HT) acquired by the control circuit 90 in step S106. As the thickness HT decreases, the thickness H1 increases.

[0080] Step S108 includes the correction processing device 30 performing correction processing on the first substrate W1 based on the thickness distribution (distribution of thickness H1) predicted by the control circuit 90 in step S107. As in step S105 of Fig. 8, the correction processing device 30 corrects the thickness of the first substrate W1 after grinding the first substrate W1 so that the difference in thickness of the first substrate W1 between the first region WA and the second region WB is reduced. The quality of the dies obtained from the first region WA can be improved to the same level as the quality of the dies obtained from the second region WB.

[0081] Although the embodiments of the substrate processing method and the 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.

[0082] This application claims priority based on Japanese Patent Application No. 2024-130800, filed with the Japan Patent Office on August 7, 2024, the entire contents of which are incorporated herein by reference.

[0083] REFERENCE SIGNS LIST 1 Substrate processing system 10 Grinding device 20 Measuring device 90 Control circuit WT Bonded substrate W1 First substrate W2 Second substrate W3, W4 Intermediate layer WA First region WB Second region

Claims

1. A substrate processing method for a bonded substrate having a first substrate, a second substrate bonded to the first substrate, and an intermediate layer provided between the first and second substrates, comprising grinding the first substrate, the substrate processing method comprising: acquiring positional information of a radially inner end of a first region in which the thickness of the bonded substrate decreases from the radially inner side toward the radially outer side of the bonded substrate before grinding the first substrate; and measuring the thickness of the first substrate after grinding in a circular second region that is located radially inward from the radially inner end of the first region by a set distance or more.

2. A substrate processing method as described in claim 1, wherein a plurality of measurement points are set for measuring the thickness of the first substrate in the second region after grinding of the first substrate, the plurality of measurement points being at different distances from the center of the first substrate, and one of the measurement points being set at the radially outer end of the second region.

3. A substrate processing method according to claim 2, comprising: rotating the bonded substrates together with a holder that holds the bonded substrates when grinding the first substrate; and controlling an inclination of a rotation center line of the holder; wherein the inclination of the rotation center line of the holder when grinding the (n+1)th and subsequent first substrates is controlled based on a radial thickness distribution of the first substrate in the second region after grinding the nth first substrate.

4. A substrate processing method according to claim 1, comprising: measuring a radial thickness distribution of the first substrate in the first region after grinding the first substrate; and performing a correction process on the first substrate after grinding the first substrate to correct the thickness of the first substrate so that the difference in thickness of the first substrate between the first region and the second region becomes smaller.

5. A substrate processing method according to claim 1, comprising: acquiring information on a radial thickness distribution of the bonded substrate in the first region before grinding the first substrate; predicting a radial thickness distribution of the first substrate in the first region after grinding the first substrate; and performing a correction process on the first substrate after grinding the first substrate to correct the thickness of the first substrate so that a difference in thickness of the first substrate between the first region and the second region is reduced.

6. A substrate processing system comprising: a grinding device for grinding a first substrate of a bonded substrate having a first substrate, a second substrate bonded to the first substrate, and an intermediate layer provided between the first and second substrates; a measuring device for measuring the thickness of the first substrate; and a control circuit for controlling the grinding device and the measuring device, wherein the control circuit performs control to acquire positional information of a radially inner end of a first region in which the thickness of the bonded substrate becomes thinner from the radially inner side toward the radially outer side of the bonded substrate before grinding of the first substrate; and control to measure the thickness of the first substrate after grinding in a circular second region that is a set distance or more radially inward from the radially inner end of the first region.

7. A substrate processing system as described in claim 6, wherein a plurality of measurement points are set for measuring the thickness of the first substrate in the second region after grinding of the first substrate, the plurality of measurement points being at different distances from the center of the first substrate, and one of the measurement points being set at the radially outer end of the second region.

8. The substrate processing system according to claim 7, wherein the grinding device comprises a holding unit that holds the bonded substrate, a rotating unit that rotates the bonded substrate together with the holding unit, and an adjusting unit that adjusts the tilt of the rotation center line of the holding unit, and the control circuit controls the tilt of the rotation center line of the holding unit when grinding the (n+1)th and subsequent first substrates based on the radial thickness distribution of the first substrate in the second region after grinding the nth first substrate.

9. A substrate processing system as described in claim 6, comprising a correction processing device that performs correction processing on the first substrate to correct the thickness of the first substrate after grinding, and the control circuit performs control to measure the radial thickness distribution of the first substrate in the first region after grinding, and control to correct the thickness of the first substrate so that the difference in thickness of the first substrate between the first region and the second region is reduced after grinding.

10. A substrate processing system as described in claim 6, comprising a correction processing device that performs correction processing on the first substrate to correct the thickness of the first substrate after grinding the first substrate, wherein the control circuit performs control to acquire information on the radial thickness distribution of the bonded substrate in the first region before grinding the first substrate, control to predict the radial thickness distribution of the first substrate in the first region after grinding the first substrate, and control to correct the thickness of the first substrate so that the difference in thickness of the first substrate between the first region and the second region is reduced after grinding the first substrate.

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