Grinding device and grinding method

Abstract

To provide an art unnecessary to switch a method for measuring the thickness of a substrate during pre-grinding of the substrate.SOLUTION: A grinder includes a chuck, a pre-grinding unit, a first optical sensor, a finish grinding unit, a second optical sensor, and a mobile mechanism. The chuck holds a substrate. The pre-grinding unit pre-grinds the substrate before finish grinding. The first optical sensor measures the thickness of the substrate during the pre-grinding. The finish grinding unit finish-grinds the substrate. The second optical sensor measures the thickness of the substrate during finish-grinding. The mobile mechanism moves the chuck between the pre-grinding position and the finish-grinding position. A measurement range of the first optical sensor is partly superimposed on a measurement range of the second optical sensor, and is wider in range, larger in lower limit value, and larger in upper limit value than the measurement range of the second optical sensor.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a grinding apparatus and a grinding method. [Background technology]

[0002] The grinding device described in Patent Document 1 detects the thickness of a semiconductor wafer with a thickness detection unit and controls continuation or stop of grinding of the semiconductor wafer. The thickness detection unit has a contact detection section that detects the thickness of the semiconductor wafer by contacting the upper surface of the semiconductor wafer, and a non-contact detection section that detects the thickness of the semiconductor wafer without contacting the upper surface of the semiconductor wafer. The thickness detection unit is also provided with a switching control section that switches the thickness detection method between the contact type and the non-contact type during grinding of the semiconductor wafer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-224678 A Summary of the Invention [Problem to be solved by the invention]

[0004] One aspect of the present disclosure provides a technique that eliminates the need to switch measurement methods for the thickness of a substrate during pre-grinding of the substrate. [Means for solving the problem]

[0005] A grinding apparatus according to one aspect of the present disclosure includes: The apparatus includes a chuck for holding a laminated substrate formed by bonding a first substrate and a second substrate, a pre-grinding unit for pre-grinding the first substrate before finish grinding, a first optical sensor for measuring a thickness of the first substrate during the pre-grinding, a finish grinding unit for the finish grinding of the first substrate, a second optical sensor for measuring a thickness of the first substrate during the finish grinding, a moving mechanism for moving the chuck between a pre-grinding position and a finish grinding position, and a control unit. The control unit performs the following operations in this order: the chuck holds the second substrate of the laminated substrate; the pre-grinding unit pre-grinds the first substrate until the measurement value of the first optical sensor changes from a value greater than an upper limit of a measurement range of the second optical sensor to a value smaller than the upper limit; the finish grinding unit finish-grinds the first substrate until the measurement value of the second optical sensor changes to a value smaller than a lower limit of the measurement range of the first optical sensor; and the chuck releases the holding of the laminated substrate. The measurement range of the first optical sensor partially overlaps with the measurement range of the second optical sensor, and is wider, has a larger lower limit, and has a larger upper limit than the measurement range of the second optical sensor. Effect of the Invention

[0006] According to one aspect of the present disclosure, it is not necessary to switch the measurement method for the thickness of a substrate during pre-grinding of the substrate. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1(A) is a cross-sectional view showing an example of a laminated substrate before grinding, and FIG. 1(B) is a cross-sectional view showing an example of the laminated substrate after grinding. [Diagram 2] FIG. 2 is a plan view showing the grinding device according to one embodiment. [Diagram 3] FIG. 3 is a side view showing an example of the grinding unit of FIG. [Figure 4] FIG. 4 is a plan view showing an example of a trajectory of the grindstone in FIG. [Diagram 5] FIG. 5 is a diagram illustrating an example of a contact sensor. [Figure 6] FIG. 6 is a diagram illustrating an example of an optical sensor. [Figure 7] FIG. 7 is a side view showing an example of an inclination angle adjustment unit of a grinding device. [Figure 8] FIG. 8(A) is a side view showing a first example of the inclination angle, FIG. 8(B) is a side view showing a second example of the inclination angle, and FIG. 8(C) is a side view showing a third example of the inclination angle. [Figure 9] FIG. 9 is a flowchart illustrating a grinding method according to one embodiment. [Figure 10] FIG. 10 is a table showing an example of a combination of thickness measuring sensors used in grinding a laminated substrate. [Figure 11] FIG. 11 is a table showing an example of a combination of thickness measuring sensors used for grinding a single substrate. [Figure 12] FIG. 12 is a table showing modified combinations of thickness measuring sensors used in grinding a single substrate. [Figure 13] FIG. 13 is a plan view showing a modified example of the grinding device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding configurations are denoted by the same reference numerals, and the description may be omitted. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is vertical.

[0009] As shown in Fig. 1(A), a first substrate W1 and a second substrate W2 are bonded to obtain a laminated substrate T. Thereafter, as shown in Fig. 1(B), the first substrate W1 is ground to be thinned. The first substrate W1 and the second substrate W2 are each, for example, a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer, or a glass substrate.

[0010] A device layer D1 is formed on the surface of the first substrate W1 facing the second substrate W2 before bonding. The device layer D1 includes electronic circuits and the like. A bonding layer F1 is formed on the surface of the device layer D1 facing the second substrate W2. The bonding layer F1 is formed of SiO2, SiC, SiCN, an adhesive, or the like. SiO2 is formed using, for example, TEOS (tetraethoxysilane).

[0011] Similarly, a device layer D2 is formed on the surface of the second substrate W2 facing the first substrate W1 before bonding. The device layer D2 includes electronic circuits and the like. A bonding layer F2 is formed on the surface of the device layer D2 facing the first substrate W1. The bonding layer F2 is formed of SiO2, SiC, SiCN, an adhesive, or the like. The SiO2 is formed using, for example, TEOS (tetraethoxysilane).

[0012] The device layer D2 may not be formed on the surface of the second substrate W2 facing the first substrate W1, and in this case, a bonding layer F2 is formed. The bonding layers F1 and F2 may be of any configuration and may not be present. If the surface of the device layer D1 is activated, the first substrate W1 and the second substrate W2 can be bonded together even without the bonding layers F1 and F2.

[0013] A total thickness HT of the laminated substrate T is equal to the sum of a thickness HA of the first substrate W1 and a thickness HB of a remainder R of the laminated substrate T excluding the first substrate W1.

[0014] Next, the grinding apparatus 1 will be described with reference to FIG. 2. The grinding apparatus 1 grinds the first substrate W1. The grinding includes polishing. The abrasive grains used for grinding may be either fixed abrasive grains or loose abrasive grains. The grinding apparatus 1 includes, for example, a rotating table 10, four chucks 20, and three grinding units 30.

[0015] The rotary table 10 holds four chucks 20 at equal intervals around a rotation center line R1 and rotates about the rotation center line R1. Each of the four chucks 20 rotates together with the rotary table 10 and moves to a carry-in / out position A0, a rough grinding position A1, a medium grinding position A2, a finish grinding position A3, and the carry-in / out position A0 in this order.

[0016] The loading / unloading position A0 serves as both a loading position where the laminated substrate T is loaded and an unloading position where the laminated substrate T is unloaded. In this embodiment, the loading position and the unloading position are the same position, but the loading position and the unloading position may be different positions. The rough grinding position A1 is a position where rough grinding is performed. The medium grinding position A2 is a position where medium grinding is performed. The finish grinding position A3 is a position where finish grinding is performed.

[0017] The four chucks 20 are attached to the rotary table 10 so as to be rotatable about their respective rotation center lines R2 (see FIG. 3). At the rough grinding position A1, the medium grinding position A2, and the finish grinding position A3, the chucks 20 rotate about their respective rotation center lines R2.

[0018] One grinding unit 30-1 is disposed at a rough grinding position A1 and performs rough grinding, another grinding unit 30-2 is disposed at a medium grinding position A2 and performs medium grinding, and the remaining grinding unit 30-3 is disposed at a finish grinding position A3 and performs finish grinding.

[0019] In this embodiment, the rotary table 10 corresponds to the moving mechanism described in the claims. Also, in this embodiment, the intermediate grinding corresponds to the pre-grinding described in the claims.

[0020] The number of grinding units 30 may be two or more, and grinding unit 30-1 may be omitted. The number of chucks 20 may be greater than the number of grinding units 30. The rotating table 10 may be omitted, and the chucks 20 may be moved in a straight line by a ball screw mechanism or the like instead of being rotated by the rotating table 10. When the rotating table 10 is omitted, the number of chucks 20 may be the same as the number of grinding units 30.

[0021] Next, the grinding unit 30-1 for rough grinding will be described with reference to Fig. 3. The grinding unit 30-2 for medium grinding and the grinding unit 30-3 for finish grinding are configured similarly to the grinding unit 30-1 for rough grinding, and therefore description thereof will be omitted.

[0022] The grinding unit 30 includes a movable part 31 to which a grinding tool C is attached. The grinding tool C is brought into contact with the first substrate W1 to grind the first substrate W1. The grinding tool C includes, for example, a disk-shaped grinding wheel C1 and a plurality of grindstones C2 arranged in a ring shape on the lower surface of the grinding wheel C1.

[0023] 4, the trajectory E of the multiple grindstones C2 arranged in a ring shape is set to pass through the center of the upper surface of the first substrate W1. The first substrate W1 is attracted to the chuck 20 so that the center of the upper surface of the first substrate W1 passes through the rotation center line R2 of the chuck 20. As the first substrate W1 rotates together with the chuck 20, the entire upper surface of the first substrate W1 is ground by the grindstones C2.

[0024] In this embodiment, the grinding wheels C2 are arranged in a ring shape on the outer periphery of the lower surface of the grinding wheel C1, but the technology of the present disclosure is not limited to this. The grinding wheels C2 may be fixed to the entire lower surface of the grinding wheel C1.

[0025] The movable part 31 has a flange 32 on which the grinding tool C is attached, a spindle shaft 33 on whose lower end the flange 32 is provided, and a spindle motor 34 that rotates the spindle shaft 33. The flange 32 is arranged horizontally, and the grinding tool C is attached to its lower surface. The spindle shaft 33 is arranged vertically. The spindle motor 34 rotates the spindle shaft 33, thereby rotating the grinding tool C attached to the flange 32. A rotation center line R3 of the grinding tool C is the rotation center line of the spindle shaft 33.

[0026] The grinding unit 30 further has a lifting section 35 which raises and lowers the movable section 31. The lifting section 35 has, for example, a vertical Z-axis guide 36, a Z-axis slider 37 which moves along the Z-axis guide 36, and a Z-axis motor 38 which moves the Z-axis slider 37. The movable section 31 is fixed to the Z-axis slider 37, and the movable section 31 and the grinding tool C rise and fall together with the Z-axis slider 37. The lifting section 35 further has a position detector 39 which detects the position of the grinding tool C. The position detector 39 detects, for example, the rotation of the Z-axis motor 38 to detect the position of the grinding tool C.

[0027] The lifting unit 35 lowers the grinding tool C from the standby position. The grinding tool C rotates while descending, comes into contact with the upper surface of the rotating overlapped substrate T, and grinds the entire upper surface of the first substrate W1. While the first substrate W1 is being ground, a grinding fluid is supplied to the upper surface of the first substrate W1. When the total thickness HT of the overlapped substrate T or the thickness HA of the first substrate W1 reaches a set value, the lifting unit 35 stops the lowering of the grinding tool C. The lifting unit 35 then raises the grinding tool C to the standby position.

[0028] Next, the arrangement of the thickness measuring sensors will be described with reference to Fig. 2 again. As shown in Fig. 2, the grinding apparatus 1 is equipped with, as thickness measuring sensors for measuring the thickness of the substrate, for example, a first contact sensor CS1, a second contact sensor CS2, a third contact sensor CS3, a first optical sensor OS1, a second optical sensor OS2, and a third optical sensor OS3.

[0029] The first contact sensor CS1 is disposed at the rough grinding position A1 and measures the total thickness HT of the laminated substrate T. The second contact sensor CS2 is disposed at the intermediate grinding position A2 and measures the thickness of a single substrate, which will be described later. The third contact sensor CS3 is disposed at the finish grinding position A3 and measures the thickness of a single substrate.

[0030] The first optical sensor OS1 is connected to the optical head OH1 via the optical fiber OF1 and measures the thickness HA of the first substrate W1. Similarly, the second optical sensor OS2 is connected to the optical head OH2 via the optical fiber OF2 and measures the thickness HA of the first substrate W1. Moreover, the third optical sensor OS3 is connected to the optical head OH3 via the optical fiber OF3 and measures the thickness HA of the first substrate W1.

[0031] The optical head OH1 is disposed at an intermediate grinding position A2. The optical head OH2 is disposed at a finish grinding position A3. The optical head OH3 is disposed at a carry-in / out position A0 and is movable in the radial direction of the overlapped substrate T. The optical heads OH1, OH2, OH3 each have an optical system such as an objective lens, and irradiate the overlapped substrate T with light from the optical fibers OF1, OF2, OF3, and also guide the light reflected by the overlapped substrate T to the optical fibers OF1, OF2, OF3.

[0032] Next, the thickness measurement by the first contact sensor CS1 will be described with reference to Fig. 5. Note that the thickness measurement by the second contact sensor CS2 and the thickness measurement by the third contact sensor CS3 are similar to the thickness measurement by the first contact sensor CS1, so the description will be omitted.

[0033] The first contact sensor CS1 has, for example, a contact head CS1a and two probes CS1b and CS1c. The contact head CS1a holds the two probes CS1b and CS1c. One probe CS1b contacts the upper surface, which is the holding surface 21, of the chuck 20 and measures the height of the upper surface of the chuck 20. The other probe CS1c contacts the upper surface of the overlapped substrate T and measures the height of the upper surface of the overlapped substrate T. The first contact sensor CS1 measures the difference between the height of the upper surface of the overlapped substrate T and the height of the upper surface of the chuck 20 as the total thickness HT of the overlapped substrate T.

[0034] Next, the thickness measurement by the first optical sensor OS1 will be described with reference to Fig. 6. Note that the thickness measurement by the second optical sensor OS2 and the thickness measurement by the third optical sensor OS3 are similar to the thickness measurement by the first optical sensor OS1, so the description will be omitted.

[0035] The first optical sensor OS1 is a non-contact sensor, and includes, for example, a light source OS1a and a light receiver OS1b. The light source OS1a is, for example, a laser oscillator. Light generated by the light source OS1a is irradiated onto the upper surface of the laminated substrate T via an optical fiber OF1 and an optical head OH1. The light reflected by the laminated substrate T is guided to the light receiver OS1b via the optical head OH1 and the optical fiber OF1. The light receiver OS1b receives, for example, light reflected by the upper surface of the first substrate W1 and light reflected by the lower surface of the first substrate W1, and measures the thickness HA of the first substrate W1.

[0036] The first optical sensor OS1 is, for example, an interference type, and measures the thickness HA of the first substrate W1 from the waveform of an interference wave between light reflected on the upper surface of the first substrate W1 and light reflected on the lower surface of the first substrate W1. Note that the first optical sensor OS1 is not limited to an interference type, and may be of another type, such as a confocal type. The same applies when measuring the thickness of a single substrate instead of the thickness HA of the first substrate W1.

[0037] Next, the inclination angle adjustment unit 50 will be described with reference to Fig. 7. The grinding apparatus 1 includes the inclination angle adjustment unit 50. The inclination angle adjustment unit 50 adjusts the inclination angle of the rotation center line R2 of the chuck 20. The inclination angle adjustment unit 50 is provided for each chuck 20, and adjusts the inclination angle for each chuck 20.

[0038] The chuck 20 is attached to the rotary table 10 via a support base 22 and an inclination angle adjustment unit 50. The support base 22 rotatably supports the chuck 20. A chuck motor 23 (see FIG. 3) that rotates the chuck 20 is built into, for example, the support base 22. A flange 24 is formed on the support base 22.

[0039] The tilt angle adjustment unit 50 includes three connecting portions 51 arranged at equal intervals (for example, at intervals of 120°) around the rotation center line R2 of the chuck 20. The three connecting portions 51 connect the flange 24 of the support base 22 and the rotary table 10.

[0040] Each of the two connecting portions 51 includes a motor 52 and a motion conversion mechanism 53 that converts the rotational motion of the motor 52 into linear motion of the flange 24 so as to adjust gaps G1, G2 between the flange 24 and the rotary table 10. The motion conversion mechanism 53 includes, for example, a ball screw.

[0041] The remaining connecting portion 51 fixes the gap between the flange 24 of the support base 22 and the turntable 10. However, the remaining connecting portion 51 may also be configured to enable the gap between the flange 24 of the support base 22 and the turntable 10 to be adjusted.

[0042] The inclination angle adjustment unit 50 adjusts the inclination angle by adjusting the gaps G1 and G2. When the inclination angle is changed, the contact pressure distribution between the grindstone C2 and the first substrate W1 on the trajectory E of the grindstone C2 shown in FIG. 4 changes. At positions where the contact pressure is high, the first substrate W1 is ground more rapidly than at positions where the contact pressure is low. Therefore, by adjusting the inclination angle, the plate thickness distribution in the radial direction of the first substrate W1 can be adjusted.

[0043] Next, control of the tilt angle adjustment unit 50 will be described with reference to Fig. 8. The chuck 20 has a holding surface 21 on which the laminated substrate T is held. The holding surface 21 holds the laminated substrate T from below with the first substrate W1 facing upward. The holding surface 21 of the chuck 20 is a conical surface that is symmetrical about the rotation center line R2 of the chuck 20 as highlighted in Fig. 8 etc. Because the holding surface 21 of the chuck 20 is a conical surface, it is possible to accommodate a variety of radial distributions of the thickness HB by adjusting the tilt angle.

[0044] The inclination angle is set so that the thickness HA of the first substrate W1 after finish grinding is uniform. The inclination angle is corrected based on the case where the thickness HB of the remaining portion R is uniform from the center to the periphery of the laminated substrate T as shown in Fig. 8(A). The reference inclination angle is also called a reference value.

[0045] For example, when the thickness HB of the remaining portion R gradually increases from the center toward the periphery of the laminated substrate T as shown in Fig. 8(B), the inclination angle is corrected to be smaller than the reference value. When the thickness HB of the remaining portion R gradually decreases from the center toward the periphery of the laminated substrate T as shown in Fig. 8(C), the inclination angle is corrected to be larger than the reference value.

[0046] Furthermore, even if the thickness HB of the remaining portion R gradually becomes thinner or thicker from both the center and the periphery of the laminated substrate T to the midpoint between them, the inclination angle can be corrected so that the thickness HA of the first substrate W1 after finish grinding becomes uniform.

[0047] 2, the grinding apparatus 1 includes a control unit 90. The control unit 90 is, for example, a computer, and includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The storage medium 92 stores programs that control various processes executed in the grinding apparatus 1. The control unit 90 controls the operation of the grinding apparatus 1 by having the CPU 91 execute the programs stored in the storage medium 92.

[0048] Next, the operation of the grinding apparatus 1, that is, the grinding method, will be described with reference to Fig. 9. The grinding method includes, for example, steps S1 to S7. Each of steps S1 to S7 shown in Fig. 9 is performed under the control of a control unit 90 of the grinding apparatus 1.

[0049] First, in step S1, the transfer device 2 transfers the laminated substrate T to the grinding device 1. The chuck 20 receives the laminated substrate T from the transfer device 2 at the transfer position A0. The chuck 20 holds the laminated substrate T from below with the first substrate W1 facing upward. Thereafter, the laminated substrate T moves from the transfer position A0 to the rough grinding position A1 by the rotation of the turntable 10.

[0050] Next, in step S2, the grinding unit 30-1 roughly grinds the first substrate W1. During the rough grinding, the first contact sensor CS1 monitors the change in the total thickness HT of the overlapped substrate T. It is also possible to estimate the change in the thickness HA of the first substrate W1 from the change in the total thickness HT of the overlapped substrate T. When the total thickness HT of the overlapped substrate T reaches a set value, the grinding tool C for rough grinding stops descending and rises to the original standby position. After that, the overlapped substrate T moves from the rough grinding position A1 to the medium grinding position A2 by the rotation of the turntable 10.

[0051] Next, in step S3, the grinding unit 30-2 performs intermediate grinding on the first substrate W1. During the intermediate grinding, the first optical sensor OS1 monitors the change in the thickness HA of the first substrate W1. When the thickness HA of the first substrate W1 reaches a set value, the grinding tool C for intermediate grinding stops descending and rises to the original standby position. After that, the overlapped substrate T moves from the intermediate grinding position A2 to the finish grinding position A3 by the rotation of the turntable 10.

[0052] Next, in step S4, the grinding unit 30-3 finish-grinds the first substrate W1. During the finish grinding, the second optical sensor OS2 monitors the change in the thickness HA of the first substrate W1. When the thickness HA of the first substrate W1 reaches a set value, the grinding tool C for finish grinding stops descending and rises to the original standby position. Then, the overlapped substrate T moves from the finish grinding position A3 to the carry-in / out position A0 by the rotation of the turntable 10.

[0053] Next, in step S5, the third optical sensor OS3 measures the thickness HA of the first substrate W1 after finish grinding at multiple points in the radial direction of the first substrate W1. Note that, in this embodiment, this measurement is performed by the third optical sensor OS3 at the carry-in / out position A0, but it may also be performed by the second optical sensor OS2 at the finish grinding position A3. However, in the former case, the throughput of the grinding apparatus 1 can be improved compared to the latter case.

[0054] Next, in step S6, the transfer device 2 carries the laminated substrate T out of the grinding device 1. The chuck 20 releases the hold of the laminated substrate T at the carry-in / out position A0 and delivers the laminated substrate T to the transfer device 2.

[0055] Next, in step S7, the control unit 90 checks whether the deviation of the thickness HA measured in step S5 is equal to or greater than a threshold value. The deviation is, for example, the difference between the maximum value and the minimum value (so-called TTV: Total Thickness Variation).

[0056] If the deviation is less than the threshold value (step S7, NO), the thickness HA of the first substrate W1 after finish grinding is uniform and there is no need to adjust the inclination angle of the rotation center line R2 of the chuck 20, so the current process is terminated.

[0057] On the other hand, if the deviation is equal to or greater than the threshold value (step S7, YES), the thickness HA of the first substrate W1 after finish grinding is non-uniform, so the control unit 90 carries out step S8.

[0058] In step S8, the tilt angle adjustment unit 50 adjusts the tilt angle of the rotation center line R2 of the chuck 20 so that the deviation will be less than the threshold value from the next time onwards. For example, the tilt angle is adjusted on the assumption that the distribution of the thickness HB of the remaining portion R is the same from the current time to the next time onwards. Alternatively, the difference in the distribution of the thickness HB of the remaining portion R from the current time to the next time onwards is measured by an external measuring device, and the tilt angle is adjusted taking into account the difference. Thereafter, the current process is terminated.

[0059] In this embodiment, steps S7 and S8 are performed after step S6, but they may be performed after step S5 or before step S6. Also, steps S7 and S8 may be performed before the next step S2 or after the next step S1.

[0060] Next, with reference to FIG. 10, a combination of thickness measurement sensors used in grinding the laminated substrate T will be described. A first contact sensor CS1 is used to monitor the total thickness HT of the laminated substrate T during rough grinding. A first optical sensor OS1 is used to monitor the thickness HA of the first substrate W1 during intermediate grinding. A second optical sensor OS2 is used to monitor the thickness HA of the first substrate W1 during finish grinding. A third optical sensor OS3 is used to measure the thickness HA of the first substrate W1 after finish grinding at multiple points in the radial direction of the first substrate W1.

[0061] The measurement range of the first contact sensor CS1 is, for example, 0 mm to 2 mm. The measurement range of the first optical sensor OS1 is, for example, 20 μm to 950 μm. Meanwhile, the measurement range of the second optical sensor OS2 is, for example, 5 μm to 300 μm. The measurement range of the third optical sensor OS3 is not particularly limited, but may be the same as the measurement range of the second optical sensor OS2, for example, 5 μm to 300 μm.

[0062] In this embodiment, the measurement range of the first optical sensor OS1 partially overlaps with the measurement range of the second optical sensor OS2. In addition, the measurement range of the first optical sensor OS1 is wider than the measurement range of the second optical sensor OS2 (T1 max -T1 min >T2 max -T2 min ), and the lower limit is large (T1 min >T2 min ), and the upper limit is large (T1 max >T2 min ).

[0063] Here, a reference embodiment for comparison with this embodiment will be described. The measurement range of the first optical sensor OS1 of the reference embodiment is the same as that of the second optical sensor OS2, and is, for example, 5 μm to 300 μm. The thickness HA of the first substrate W1 at the start of intermediate grinding is, for example, about 350 μm, which exceeds the upper limit of the measurement range of the first optical sensor OS1.

[0064] Therefore, in the reference embodiment, in the early stage of intermediate grinding, the second contact sensor CS2 monitors the change in the total thickness HT of the laminated substrate T. The measurement range of the second contact sensor CS2 may be the same as that of the first contact sensor CS1, for example, 0 mm to 2 mm. It is also possible to estimate the change in the thickness HA of the first substrate W1 from the change in the total thickness HT of the laminated substrate T. On the other hand, in the final stage of intermediate grinding, the first optical sensor OS1 monitors the change in the thickness HA of the first substrate W1. The optical sensor is superior in thickness measurement accuracy to the contact sensor. In order to accurately control the thickness HA of the first substrate W1 at the end of intermediate grinding, the thickness measurement method is switched in the middle of intermediate grinding. This makes thickness monitoring complicated.

[0065] According to this embodiment, as described above, the measurement range of the first optical sensor OS1 partially overlaps with the measurement range of the second optical sensor OS2, and the range is wider, the lower limit value is larger, and the upper limit value is larger than the measurement range of the second optical sensor OS2. Therefore, it is not necessary to switch the thickness measurement method during intermediate grinding, and the thickness HA of the first substrate W1 can be monitored by the first optical sensor OS1 from the beginning to the end of intermediate grinding. In addition, it is not necessary to switch the thickness measurement method during finish grinding, and the thickness HA of the first substrate W1 can be monitored by the second optical sensor OS2 from the beginning to the end of finish grinding. Therefore, it is possible to easily monitor the thickness.

[0066] According to this embodiment, the thickness HA (e.g., 350 μm) of the first substrate W1 at the end of rough grinding and at the start of intermediate grinding is within the measurement range of the first optical sensor OS1 (e.g., within the range of 20 μm to 950 μm). The thickness HA (e.g., 100 μm) of the first substrate W1 at the end of intermediate grinding and at the start of finish grinding is within the measurement range of the first optical sensor OS1 (e.g., within the range of 20 μm to 950 μm) and within the measurement range of the second optical sensor OS2 (e.g., within the range of 5 μm to 300 μm). In addition, the thickness HA (e.g., 10 μm) of the first substrate W at the end of finish grinding is smaller than the lower limit (e.g., 20 μm) of the measurement range of the first optical sensor OS1 and is within the measurement range of the second optical sensor OS2 and the third optical sensor OS3 (e.g., within the range of 5 μm to 300 μm).

[0067] Next, we will explain the initial adjustment of the chuck 20. After the chuck 20 is attached to the rotary table 10, it is first ground by the grinding unit 30 with the rotation center line R2 of the chuck 20 tilted. As a result, the holding surface 21 of the chuck 20 becomes a conical surface symmetrical about the rotation center line R2 of the chuck 20 as highlighted in FIG. 8 etc.

[0068] Thereafter, the substrate is ground while being held on the holding surface 21 of the chuck 20. Next, the thickness of the substrate is measured at a plurality of radial points of the substrate, and the tilt angle adjustment unit 50 adjusts the tilt angle of the rotation center line R2 of the chuck 20 so that the deviation of the thickness becomes less than a threshold value. In addition to adjusting the tilt angle, the holding surface 21 of the chuck 20 may be re-ground as an initial adjustment to improve the degree of adhesion between the machine parts.

[0069] The present inventors have found through experiments and the like that the initial adjustment can be easily performed by using a single substrate instead of the laminated substrate T. This is because the distribution of the thickness HB of the remaining portion R of the laminated substrate T is complex, and if an attempt is made to adjust the tilt angle taking the distribution into account, the calculation of the tilt angle becomes complicated and the reproducibility becomes low.

[0070] In this embodiment, a single substrate is used for the initial adjustment instead of the laminated substrate T. The single substrate is, for example, a semiconductor substrate or a glass substrate, similar to the first substrate W1. The thickness of the single substrate after finish grinding is measured by an optical sensor, similar to the thickness HA of the first substrate W1 after finish grinding. In the case of an optical type, the thickness of the substrate can be measured with high accuracy even if the height of the optical head fluctuates when the optical head is moved to measure the thickness at multiple points.

[0071] This is because the optical sensor measures the thickness of the substrate from the waveform of the interference wave between the light reflected by the upper surface of the substrate and the light reflected by the lower surface of the substrate. The waveform of the interference wave is determined by the thickness of the substrate and does not depend on the height of the optical head. Not only in the case of the interference type, but also in the case of other methods such as the confocal type, the thickness of the substrate can be measured regardless of the height of the optical head. On the other hand, in the case of the contact type, if the height of the contact head fluctuates when moving the contact head to measure the thickness at multiple points, the measured thickness of the substrate also fluctuates.

[0072] Although the optical sensor can measure the thickness HA of the first substrate W1 of the laminated substrate T, it cannot measure the total thickness HT of the laminated substrate T. This is because the metal layers of the device layers D1 and D2 of the laminated substrate T block light. Since the optical sensor cannot measure the total thickness HT of the laminated substrate T, it is also not possible to adjust the tilt angle based on the deviation of the total thickness HT.

[0073] As described above, in this embodiment, a single substrate is used for the initial adjustment instead of the overlapped substrate T. The grinding method for the single substrate is the same as the grinding method for the overlapped substrate T. However, the thickness of the single substrate after finish grinding is set to be thicker than the thickness HA of the first substrate W1 of the overlapped substrate T after finish grinding. If the thicknesses were set to be approximately the same, the thickness of the single substrate after finish grinding would be too thin, making it difficult to transport it alone.

[0074] When grinding a single substrate, the target thicknesses in rough grinding, medium grinding, and finish grinding are set to be thicker than when grinding the first substrate W1 of the overlapped substrate T. Therefore, when grinding a single substrate, a different combination of thickness measurement sensors is used than when grinding the first substrate W1 of the overlapped substrate T.

[0075] Next, with reference to FIG. 11, the grinding of a single substrate and the combination of a thickness measuring sensor used in the grinding will be described.

[0076] In step S2, the grinding unit 30-1 roughly grinds the single substrate. During the rough grinding, the first contact sensor CS1 monitors the change in thickness of the single substrate. The measurement range of the first contact sensor CS1 is not particularly limited, but is, for example, 0 mm to 2 mm. When the thickness of the substrate reaches a set value, the grinding tool C for rough grinding stops descending and rises to the original standby position. After that, the single substrate moves from the rough grinding position A1 to the medium grinding position A2 by the rotation of the turntable 10.

[0077] In step S3, the grinding unit 30-2 performs intermediate grinding on a single substrate. During intermediate grinding, the thickness of the substrate exceeds the upper limit (e.g., 950 μm) of the measurement range of the first optical sensor OS1. Therefore, during intermediate grinding, the second contact sensor CS2 monitors the change in thickness of the substrate. The measurement range of the second contact sensor CS2 is not particularly limited, but is, for example, 0 mm to 2 mm. When the thickness of the substrate reaches a set value, the grinding tool C for intermediate grinding is stopped from descending and rises to the original standby position. Thereafter, the single substrate is moved from the intermediate grinding position A2 to the finish grinding position A3 by the rotation of the turntable 10.

[0078] In step S4, the grinding unit 30-3 finish-grinds the single substrate. During the finish grinding, the thickness of the substrate exceeds the upper limit (e.g., 300 μm) of the measurement range of the second optical sensor OS2. Therefore, during the finish grinding, the third contact sensor CS3 monitors the change in the thickness of the substrate. The measurement range of the third contact sensor CS3 is not particularly limited, but is, for example, 0 mm to 2 mm. When the thickness of the substrate reaches a set value, the grinding tool C for finish grinding is stopped from descending and rises to the original standby position. Thereafter, the single substrate is returned from the finish grinding position A3 to the intermediate grinding position A2 by the rotation of the turntable 10.

[0079] In step S5, the first optical sensor OS1, not the third optical sensor OS3, measures the thickness of a single substrate after finish grinding at multiple points in the radial direction of the substrate. The measurement range of the first optical sensor OS1 is, for example, 20 μm to 950 μm. On the other hand, the measurement range of the third optical sensor OS3 is, for example, 5 μm to 300 μm.

[0080] The measurement range of the third optical sensor OS3 is determined in consideration of the thickness HA of the first substrate W1 of the overlapped substrate T after finish grinding of the overlapped substrate T. The thickness HA after finish grinding is not particularly limited, but is, for example, about 10 μm. On the other hand, the thickness of a single substrate after finish grinding is not particularly limited, but is, for example, about 500 μm from the viewpoint of transportation, and is outside the measurement range of the third optical sensor OS3.

[0081] Therefore, the first optical sensor OS1, not the third optical sensor OS3, measures the thickness of a single substrate after finish grinding by the first optical sensor OS1. The measurement range of the first optical sensor OS1 partially overlaps with the measurement range of the third optical sensor OS3, and is wider than the measurement range of the third optical sensor OS3 (T1 max -T1 min >T3 max -T3 min ), and the lower limit is large (T1 min >T3 min ), and the upper limit is large (T1 max >T3 max). As a result, the thickness of the single substrate after finish grinding falls within the measurement range of the first optical sensor OS1. Therefore, by using the first optical sensor OS1, the thickness of the single substrate after finish grinding can be measured at multiple points in the radial direction of the substrate.

[0082] Thereafter, steps S6 to S8 are performed. In steps S7 to S8, the measurement results of the first optical sensor OS1 are used. If a single substrate is used instead of the laminated substrate T, it becomes unnecessary to take into account the complex distribution of the thickness HB of the remaining portion R of the laminated substrate T in the initial adjustment. This makes the initial adjustment easy. Specifically, calculation of the tilt angle is easy, and the reproducibility is also high.

[0083] The initial adjustment is performed for each chuck 20. Steps S1 to S7 are performed for each chuck 20. That is, for each chuck 20, grinding of a single substrate (e.g., rough grinding, medium grinding, and finish grinding) is performed, the thickness of the substrate after finish grinding is measured, and the inclination angle of the rotation center line R2 of the chuck 20 is adjusted.

[0084] 10 and 11, the single substrate is placed at the intermediate grinding position A2 in step S5, unlike the laminated substrate T. The single substrate moves from the finish grinding position A3 to the intermediate grinding position A2, and then moves from the intermediate grinding position A2 to the carry-in / out position A0. As a result, the throughput of the grinding apparatus 1 decreases.

[0085] 12, the single substrate may be placed at the load / unload position A0 in step S5, similarly to the laminated substrate T. In this case, the single substrate is moved to the rough grinding position A1, the intermediate grinding position A2, the finish grinding position A3, and the load / unload position A0 in this order. This improves the throughput of the grinding apparatus 1.

[0086] In order to set the position of the single substrate in step S5 to the load / unload position A0, the combination of the optical sensor and the optical head connected to each other via the optical fiber may be switched between grinding a single substrate and grinding a laminated substrate T. For example, as shown in Fig. 13, the first optical sensor OS1 is connected to the optical head LS3 arranged above the load / unload position A0 via the optical fiber OF3, and measures the thickness of the single substrate after finish grinding at multiple points in the radial direction of the substrate.

[0087] In this embodiment, the first optical sensor OS1 and the optical head LS3 are connected via an optical fiber OF3, but may be connected via another optical fiber OF1. That is, in this embodiment, the combination of the optical sensor and the optical head is switched by reconnecting the optical sensor and the optical fiber, but may be switched by reconnecting the optical fiber and the optical head. These reconnections may be performed manually or automatically by a robot.

[0088] Although the grinding device and grinding method according to the present disclosure have been described above, the present disclosure is not limited to the above-mentioned 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. [Explanation of symbols]

[0089] 1 Grinding equipment 10 Rotating table (moving mechanism) 20 Chuck 30-2 Grinding unit (pre-grinding unit) 30-3 Grinding unit (finish grinding unit) OS1 1st optical sensor OS2 Second optical sensor W1 First board

Claims

1. a chuck for holding a laminated substrate formed by bonding the first substrate and the second substrate; a pre-grinding unit that pre-grinds the first substrate before finish-grinding the first substrate; a first optical sensor for measuring a thickness of the first substrate during the pre-grinding; a finish grinding unit that performs the finish grinding on the first substrate; a second optical sensor for measuring a thickness of the first substrate during the finish grinding; a moving mechanism that moves the chuck between the pre-grinding position and the finish grinding position; A control unit; Equipped with The control unit is the chuck holding the second substrate of the laminated substrate; the pre-grinding unit pre-grinds the first substrate until a measurement value of the first optical sensor changes from a value greater than an upper limit of a measurement range of the second optical sensor to a value smaller than the upper limit; the finish grinding unit finish-grinds the first substrate until a measurement value of the second optical sensor becomes smaller than a lower limit of a measurement range of the first optical sensor; the chuck releasing the holding of the laminated substrate; and Do the following in this order: A grinding apparatus in which the measurement range of the first optical sensor partially overlaps with the measurement range of the second optical sensor, and the measurement range of the first optical sensor is wider, has a larger lower limit, and has a larger upper limit than the measurement range of the second optical sensor.

2. a third optical sensor that measures a thickness of the first substrate after the finish grinding at a plurality of points in a radial direction of the first substrate; 2. The grinding device according to claim 1, wherein the measurement range of the first optical sensor partially overlaps with the measurement range of the third optical sensor, and is wider, has a larger lower limit, and has a larger upper limit than the measurement range of the third optical sensor.

3. When the laminated substrate is held by the chuck, the third optical sensor measures a thickness of the first substrate after the finish grinding at a plurality of points in a radial direction of the first substrate; The grinding apparatus according to claim 2, wherein when a single substrate is held by the chuck instead of the laminated substrate, the first optical sensor measures the thickness of the single substrate after the finish grinding at multiple radial points of the single substrate.

4. The moving mechanism moves the chuck between the pre-grinding position, the finish grinding position, and a position where the chuck is carried out by a transport device; The grinding apparatus of claim 3, wherein when the single substrate is held by the chuck, the single substrate is positioned at the unloading position when the first optical sensor measures the thickness of the single substrate after the finish grinding at multiple radial points of the single substrate.

5. The moving mechanism moves the chuck between the pre-grinding position, the finish grinding position, and a position where the chuck is carried out by a transport device; The grinding apparatus of claim 3, wherein when the single substrate is held by the chuck, the single substrate is positioned at a pre-grinding position when the first optical sensor measures the thickness of the single substrate after the finish grinding at multiple radial points of the single substrate.

6. a tilt angle adjustment unit for adjusting a tilt angle of a rotation center line of the chuck; The grinding device according to any one of claims 3 to 5, wherein the control unit controls the inclination angle adjustment unit to adjust the inclination angle of the rotation center line of the chuck so that the thickness of the single substrate after the finish grinding is uniform.

7. holding a laminated substrate formed by bonding the first substrate and the second substrate with a chuck; a pre-grinding unit pre-grinding the first substrate before the finish grinding unit finishes the first substrate; measuring a thickness of the first substrate with a first optical sensor during the pre-grinding; the finish grinding unit performs the finish grinding on the first substrate; measuring a thickness of the first substrate by a second optical sensor during the finish grinding; a moving mechanism moving the chuck between the pre-grinding position and the finish grinding position; Including, the chuck holding the second substrate of the laminated substrate; the pre-grinding unit pre-grinds the first substrate until a measurement value of the first optical sensor changes from a value greater than an upper limit of a measurement range of the second optical sensor to a value smaller than the upper limit; the finish grinding unit finish-grinds the first substrate until a measurement value of the second optical sensor becomes smaller than a lower limit of a measurement range of the first optical sensor; the chuck releasing the holding of the laminated substrate; and in that order, A grinding method, wherein the measurement range of the first optical sensor partially overlaps with the measurement range of the second optical sensor, and is wider, has a larger lower limit, and has a larger upper limit than the measurement range of the second optical sensor.

8. measuring a thickness of the first substrate after the finish grinding at a plurality of points in a radial direction of the first substrate by a third optical sensor; 8. The grinding method according to claim 7, wherein the measurement range of the first optical sensor partially overlaps with the measurement range of the third optical sensor, and is wider, has a larger lower limit, and has a larger upper limit than the measurement range of the third optical sensor.

9. When the laminated substrate is held by the chuck, the third optical sensor measures a thickness of the first substrate after the finish grinding at a plurality of points in a radial direction of the first substrate; The grinding method according to claim 8, further comprising: when a single substrate is held by the chuck instead of the laminated substrate, the first optical sensor measures a thickness of the single substrate after the finish grinding at multiple radial points of the single substrate.

10. The method includes the step of moving the chuck between a pre-grinding position, a finish grinding position, and a conveying device for conveying the chuck out, The grinding method according to claim 9, wherein, when the single substrate is held by the chuck, the single substrate is positioned at the unloading position when the first optical sensor measures the thickness of the single substrate after the finish grinding at multiple radial points of the single substrate.

11. The method includes the step of moving the chuck between a pre-grinding position, a finish grinding position, and a conveying device for conveying the chuck out, The grinding method according to claim 9, wherein, when the single substrate is held by the chuck, the single substrate is positioned at a pre-grinding position when the first optical sensor measures the thickness of the single substrate after the finish grinding at multiple radial points of the single substrate.

12. The grinding method according to any one of claims 9 to 11, further comprising an inclination angle adjustment unit adjusting an inclination angle of a rotation center line of the chuck so that a thickness of the single substrate after the finish grinding is uniform.

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