JP2022011997A - Grinder and griding method - Google Patents

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

The present disclosure relates to a grinding device and a grinding method.

The grinding apparatus described in Patent Document 1 detects the thickness of a semiconductor wafer with a thickness detecting unit, and controls the continuation or stop of grinding of the semiconductor wafer. The thickness detection unit has a contact type detection unit that detects the thickness of the semiconductor wafer by contacting the upper surface of the semiconductor wafer, and a non-contact type detection unit that detects the thickness of the semiconductor wafer without contacting the upper surface of the semiconductor wafer. .. Further, the thickness detection unit is provided with a switching control unit for switching the thickness detection method between the contact type and the non-contact type during grinding of the semiconductor wafer.

Japanese Unexamined Patent Publication No. 2011-224678

One aspect of the present disclosure provides a technique that eliminates the need to switch the method for measuring the thickness of a substrate during pre-grinding of the substrate.

The grinding apparatus according to one aspect of the present disclosure includes a chuck, a pre-grinding unit, a first optical sensor, a finish grinding unit, a second optical sensor, and a moving mechanism. The chuck holds the substrate. The pre-grinding unit pre-grinds the substrate before finishing grinding. The first optical sensor measures the thickness of the substrate during the pre-grinding. The finish grinding unit grinds the substrate. The second optical sensor measures the thickness of the substrate during the finish grinding. The moving mechanism moves the chuck between the pre-grinding position and the finish grinding position. The measurement range of the first optical sensor partially overlaps with the measurement range of the second optical sensor, and the range is wider than the measurement range of the second optical sensor. , The lower limit is large and the upper limit is large.

According to one aspect of the present disclosure, it is not necessary to switch the method for measuring the thickness of the substrate during the pre-grinding of the substrate.

FIG. 1A is a cross-sectional view showing an example of a polymerized substrate before grinding, and FIG. 1B is a cross-sectional view showing an example of a polymerized substrate after grinding. FIG. 2 is a plan view showing a grinding device according to an embodiment. FIG. 3 is a side view showing an example of the grinding unit of FIG. 2. FIG. 4 is a plan view showing an example of the trajectory of the grindstone of FIG. FIG. 5 is a diagram showing an example of a contact type sensor. FIG. 6 is a diagram showing an example of an optical sensor. FIG. 7 is a side view showing an example of the inclination angle adjusting portion of the grinding device. 8 (A) is a side view showing a first example of the tilt angle, FIG. 8 (B) is a side view showing a second example of the tilt angle, and FIG. 8 (C) is a side view showing a third example of the tilt angle. Is. FIG. 9 is a flowchart showing a grinding method according to an embodiment. FIG. 10 is a table showing an example of a combination of thickness measuring sensors used for grinding a polymerized substrate. FIG. 11 is a table showing an example of a combination of thickness measuring sensors used for grinding a single substrate. FIG. 12 is a table showing a modified example of a combination of thickness measuring sensors used for grinding a single substrate. FIG. 13 is a plan view showing a modified example of the grinding device.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding configurations may be designated by the same reference numerals and description thereof may be omitted. In the present 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 the horizontal direction, and the Z-axis direction is the vertical direction.

As shown in FIG. 1A, the first substrate W1 and the second substrate W2 are joined to obtain a polymerization substrate T. Then, as shown in FIG. 1 (B), the first substrate W1 is ground and thinned. The first substrate W1 and the second substrate W2 are, for example, a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer, a glass substrate, or the like, respectively.

A device layer D1 is formed on the surface of the first substrate W1 facing the second substrate W2 before joining. The device layer D1 includes an electronic circuit 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 SiO ₂ , SiC, SiCN, an adhesive or the like. SiO ₂ is formed using, for example, TEOS (tetraethoxylane).

Similarly, the device layer D2 is formed on the surface of the second substrate W2 facing the first substrate W1 before joining. The device layer D2 includes an electronic circuit 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 SiO ₂ , SiC, SiCN, an adhesive or the like. SiO ₂ is formed using, for example, TEOS (tetraethoxylane).

The device layer D2 does not have to be formed on the surface of the second substrate W2 facing the first substrate W1, and in this case, the bonding layer F2 is formed. Further, the bonding layers F1 and F2 have an arbitrary configuration and may be omitted. If the surface of the device layer D1 is activated, the first substrate W1 and the second substrate W2 can be bonded without the bonding layers F1 and F2.

The total thickness HT of the polymerization substrate T is equal to the sum of the thickness HA of the first substrate W1 and the thickness HB of the balance R excluding the first substrate W1 of the polymerization substrate T.

Next, the grinding apparatus 1 will be described with reference to FIG. The grinding device 1 grinds the first substrate W1. Grinding involves polishing. The abrasive grains used for grinding may be either fixed abrasive grains or free abrasive grains. The grinding device 1 includes, for example, a rotary table 10, four chucks 20, and three grinding units 30.

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

The carry-in / out position A0 serves both as a carry-in position where the polymerization substrate T is carried in and a carry-out position where the polymerization substrate T is carried out. In this embodiment, the carry-in position and the carry-out position are the same, but the carry-in position and the carry-out position may be different. 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 the finish grinding is performed.

The four chucks 20 are rotatably attached to the rotary table 10 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 chuck 20 rotates about the respective rotation center line R2.

One grinding unit 30-1 is arranged at the rough grinding position A1 and performs rough grinding. Another grinding unit 30-2 is arranged at the medium grinding position A2 to perform medium grinding. The remaining grinding units 30-3 are arranged at the finish grinding position A3 to perform finish grinding.

In this embodiment, the rotary table 10 corresponds to the moving mechanism described in the claims. Further, in the present embodiment, the medium grinding corresponds to the pre-grinding described in the claims.

The number of grinding units 30 may be two or more, and the grinding unit 30-1 may be omitted. Further, the number of chucks 20 may be larger than the number of grinding units 30. The rotary table 10 may be omitted, and the chuck 20 may be driven straight by a ball screw mechanism or the like instead of being rotated by the rotary table 10. If there is no rotary table 10, the number of chucks 20 may be the same as the number of grinding units 30.

Next, the grinding unit 30-1 for rough grinding will be described with reference to FIG. Since the grinding unit 30-2 for medium grinding and the grinding unit 30-3 for finish grinding are configured in the same manner as the grinding unit 30-1 for rough grinding, the description thereof will be omitted.

The grinding unit 30 includes a movable portion 31 on which the grinding tool C is mounted. 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.

As shown in FIG. 4, the trajectories E of the plurality of grindstones C2 arranged in a ring shape are set so as to pass through the center of the upper surface of the first substrate W1. Further, 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 grindstone C2.

In the present embodiment, a plurality of grindstones C2 are arranged in a ring shape on the outer peripheral portion of the lower surface of the grinding wheel C1, but the technique of the present disclosure is not limited to this. The grindstone C2 may be fixed to the entire lower surface of the grinding wheel C1.

The movable portion 31 has a flange 32 on which the grinding tool C is mounted, a spindle shaft 33 on which the flange 32 is provided at the lower end, and a spindle motor 34 for rotating the spindle shaft 33. The flange 32 is arranged horizontally, and the grinding tool C is mounted on the lower surface thereof. The spindle shaft 33 is arranged vertically. The spindle motor 34 rotates the spindle shaft 33 and rotates the grinding tool C mounted on the flange 32. The rotation center line R3 of the grinding tool C is the rotation center line of the spindle shaft 33.

The grinding unit 30 further has an elevating portion 35 that elevates and elevates the movable portion 31. The elevating portion 35 has, for example, a vertical Z-axis guide 36, a Z-axis slider 37 that moves along the Z-axis guide 36, and a Z-axis motor 38 that moves the Z-axis slider 37. A movable portion 31 is fixed to the Z-axis slider 37, and the movable portion 31 and the grinding tool C move up and down together with the Z-axis slider 37. The elevating unit 35 further includes a position detector 39 for detecting the position of the grinding tool C. The position detector 39 detects, for example, the rotation of the Z-axis motor 38 and detects the position of the grinding tool C.

The elevating part 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 polymerized substrate T, and grinds the entire upper surface of the first substrate W1. During the grinding of the first substrate W1, the grinding liquid is supplied to the upper surface of the first substrate W1. When the total thickness HT of the polymerized substrate T or the thickness HA of the first substrate W1 reaches the set value, the elevating portion 35 stops the lowering of the grinding tool C. After that, the elevating part 35 raises the grinding tool C to the standby position.

Next, the arrangement of the thickness measuring sensor will be described with reference to FIG. 2 again. As shown in FIG. 2, as a thickness measuring sensor for measuring the thickness of the substrate, the grinding device 1 includes, for example, a first contact type sensor CS1, a second contact type sensor CS2, a third contact type sensor CS3, and a second. It includes one optical sensor OS 1, a second optical sensor OS 2, and a third optical sensor OS 3.

The first contact type sensor CS1 is arranged at the rough grinding position A1 and measures the total thickness HT of the polymerization substrate T. The second contact type sensor CS2 is arranged at the middle grinding position A2 and measures the thickness of a single substrate, which will be described later. The third contact type sensor CS3 is arranged at the finish grinding position A3 and measures the thickness of a single substrate.

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. Further, 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.

The optical head OH1 is arranged at the middle grinding position A2. The optical head OH2 is arranged at the finish grinding position A3. The optical head OH3 is arranged at the carry-in / out position A0 and can move in the radial direction of the polymerization substrate T. The optical heads OH1, OH2, and OH3 have an optical system such as an objective lens, irradiate the polymerization substrate T with light from the optical fibers OF1, OF2, and OF3, and illuminate the light reflected by the polymerization substrate T. Lead to fibers OF1, OF2, OF3.

Next, the thickness measurement by the first contact type sensor CS1 will be described with reference to FIG. Since the thickness measurement by the second contact sensor CS2 and the thickness measurement by the third contact sensor CS3 are the same as the thickness measurement by the first contact sensor CS1, the description thereof will be omitted.

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

Next, the thickness measurement by the first optical sensor OS1 will be described with reference to FIG. Since the thickness measurement by the second optical sensor OS2 and the thickness measurement by the third optical sensor OS3 are the same as the thickness measurement by the first optical sensor OS1, the description thereof will be omitted.

The first optical sensor OS1 is a non-contact type sensor, and includes, for example, a light source OS1a and a light receiver OS1b. The light source OS1a is, for example, a laser oscillator. The light generated by the light source OS1a is applied to the upper surface of the polymerization substrate T via the optical fiber OF1 and the optical head OH1. The light reflected by the polymerization substrate T is guided to the receiver OS1b via the optical head OH1 and the optical fiber OF1. The receiver OS1b receives, for example, the light reflected on the upper surface of the first substrate W1 and the light reflected on the lower surface of the first substrate W1 and measures the thickness HA of the first substrate W1.

The first optical sensor OS1 is, for example, an interferometric type, and is based on the waveform of an interference wave between the light reflected on the upper surface of the first substrate W1 and the light reflected on the lower surface of the first substrate W1, the first substrate W1. Thickness HA is measured. The first optical sensor OS1 is not limited to the interferometric type, and may be another type such as a confocal type. The same applies to the case where the thickness of a single substrate is measured instead of the thickness HA of the first substrate W1.

Next, the tilt angle adjusting unit 50 will be described with reference to FIG. 7. The grinding device 1 includes a tilt angle adjusting unit 50. The tilt angle adjusting unit 50 adjusts the tilt angle of the rotation center line R2 of the chuck 20. The tilt angle adjusting unit 50 is provided for each chuck 20 and adjusts the tilt angle for each chuck 20.

The chuck 20 is mounted on the rotary table 10 via the support base 22 and the tilt angle adjusting portion 50. The support base 22 rotatably supports the chuck 20. The chuck motor 23 (see FIG. 3) that rotates the chuck 20 is built in, for example, inside the support base 22. A flange 24 is formed on the support base 22.

The tilt angle adjusting portion 50 includes three connecting portions 51 arranged at equal intervals (for example, 120 ° intervals) 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.

The two connecting portions 51 include a motor 52 and a motion conversion mechanism 53 that converts the rotational motion of the motor 52 into a linear motion of the flange 24 so that the gaps G1 and G2 between the flange 24 and the rotary table 10 can be adjusted, respectively. including. The motion conversion mechanism 53 includes, for example, a ball screw.

The remaining one connecting portion 51 fixes the gap between the flange 24 of the support base 22 and the rotary table 10. However, the remaining one connecting portion 51 may also be configured so that the gap between the flange 24 of the support base 22 and the rotary table 10 can be adjusted.

The tilt angle adjusting unit 50 adjusts the tilt angle by adjusting the gaps G1 and G2. When the inclination angle changes, 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 the position where the contact pressure is high, the grinding of the first substrate W1 proceeds as compared with the position where the contact pressure is low. Therefore, the plate thickness distribution in the radial direction of the first substrate W1 can be adjusted by adjusting the inclination angle.

Next, the control of the tilt angle adjusting unit 50 will be described with reference to FIG. The chuck 20 has a holding surface 21 on which the polymerization substrate T is held. The holding surface 21 holds the polymerization board T from below with the first board W1 facing up. The holding surface 21 of the chuck 20 is a conical surface symmetrical with respect to the rotation center line R2 of the chuck 20 as emphasized in FIG. 8 and the like. Since the holding surface 21 of the chuck 20 is a conical surface, it is possible to cope with the radial distribution of various thicknesses HB by adjusting the inclination angle.

The inclination angle is set so that the thickness HA of the first substrate W1 after finish grinding becomes uniform. As shown in FIG. 8A, 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 peripheral edge of the polymerization substrate T. The reference tilt angle is also called the reference value.

For example, as shown in FIG. 8B, when the thickness HB of the remaining portion R gradually increases from the center of the polymerization substrate T toward the peripheral edge, the inclination angle is corrected to be smaller than the reference value. Further, as shown in FIG. 8C, when the thickness HB of the remaining portion R gradually decreases from the center of the polymerization substrate T toward the peripheral edge, the inclination angle is corrected to be larger than the reference value.

Even when the thickness HB of the remaining portion R gradually becomes thinner or thicker from both the center and the peripheral edge of the polymerization substrate T to the intermediate point thereof, the thickness HA of the first substrate W1 after finish grinding is uniform. The tilt angle can be corrected so as to be.

As shown in FIG. 2, the grinding device 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 by the grinding apparatus 1. The control unit 90 controls the operation of the grinding apparatus 1 by causing the CPU 91 to execute the program stored in the storage medium 92.

Next, with reference to FIG. 9, the operation of the grinding device 1, that is, the grinding method will be described. The grinding method includes, for example, steps S1 to S7. Each step S1 to S7 shown in FIG. 9 is carried out under the control of the control unit 90 of the grinding device 1.

First, in step S1, the transport device 2 carries the polymerization substrate T into the grinding device 1. The chuck 20 receives the polymerization substrate T from the transport device 2 at the carry-in / carry-out position A0. The chuck 20 holds the polymerization substrate T from below with the first substrate W1 facing upward. After that, the polymerization substrate T moves from the carry-in / out position A0 to the rough grinding position A1 by the rotation of the rotary table 10.

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 polymerized 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 polymerization substrate T. When the total thickness HT of the polymerized substrate T reaches the set value, the grinding tool C for rough grinding is stopped from descending and rises to the original standby position. After that, the polymerization substrate T moves from the rough grinding position A1 to the medium grinding position A2 by the rotation of the rotary table 10.

Next, in step S3, the grinding unit 30-2 middle-grinds the first substrate W1. During the middle 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 the set value, the grinding tool C for medium grinding is stopped from descending and rises to the original standby position. After that, the polymerization substrate T moves from the middle grinding position A2 to the finish grinding position A3 by the rotation of the rotary table 10.

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 the set value, the grinding tool C for finish grinding is stopped from descending and rises to the original standby position. After that, the polymerization substrate T moves from the finish grinding position A3 to the loading / unloading position A0 by the rotation of the rotary table 10.

Next, in step S5, the third optical sensor OS3 measures the thickness HA of the first substrate W1 after finish grinding at a plurality of radial points of the first substrate W1. In this embodiment, this measurement is performed by the third optical sensor OS3 at the carry-in / out position A0, but may 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 as compared with the latter case.

Next, in step S6, the transport device 2 carries out the polymerization substrate T from the grinding device 1. The chuck 20 releases the holding of the polymerization substrate T at the carry-in / out position A0, and passes the polymerization substrate T to the transfer device 2.

Next, in step S7, the control unit 90 checks whether or not the deviation of the thickness HA measured in step S5 is equal to or greater than the threshold value. The deviation is, for example, the difference between the maximum value and the minimum value (so-called TTV: Total Tickness Variation).

When 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 the inclination angle of the rotation center line R2 of the chuck 20 does not need to be adjusted. Processing is completed.

On the other hand, when 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 performs step S8.

In step S8, from the next time onward, the tilt angle adjusting unit 50 adjusts the tilt angle of the rotation center line R2 of the chuck 20 so that the deviation becomes less than the threshold value. For example, the inclination angle is adjusted on the assumption that the distribution of the thickness HB of the remaining portion R is the same between this time and the next time and thereafter. Alternatively, the difference in the distribution of the thickness HB of the remaining portion R between this time and the next time or later is measured by an external measuring device, and the inclination angle is adjusted after taking the difference into consideration. After that, this process is completed.

In this embodiment, steps S7 and S8 are carried out after step S6, but may be carried out after step S5 and may be carried out before step S6. Further, steps S7 and S8 may be performed before the next step S2, or may be performed after the next step S1.

Next, with reference to FIG. 10, a combination of thickness measuring sensors used for grinding the polymerized substrate T will be described. The first contact type sensor CS1 is used to monitor the total thickness HT of the polymerized substrate T during rough grinding. Further, the first optical sensor OS1 is used to monitor the thickness HA of the first substrate W1 during medium grinding. Further, the second optical sensor OS2 is used to monitor the thickness HA of the first substrate W1 during finish grinding. Furthermore, the third optical sensor OS3 is used to measure the thickness HA of the first substrate W1 after finish grinding at a plurality of radial points of the first substrate W1.

The measurement range of the first contact type 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. On the other hand, 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, and is, for example, 5 μm to 300 μm.

The measurement range of the first optical sensor OS1 of the present embodiment partially overlaps with the measurement range of the second optical sensor OS2. Further, 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 value is large. (T1 _min > T2 _min ) and the upper limit is large (T1 _max > T2 _min ).

Here, a reference embodiment to be compared with the present embodiment will be described. The measurement range of the first optical sensor OS1 of the reference embodiment is the same as the measurement range 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 medium grinding is, for example, about 350 μm, which exceeds the upper limit of the measurement range of the first optical sensor OS1.

Therefore, in the reference mode, the second contact type sensor CS2 monitors the change in the total thickness HT of the polymerized substrate T at the initial stage of the middle grinding. The measurement range of the second contact sensor CS2 may be the same as the measurement range of the first contact sensor CS1, and is, 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 polymerization substrate T. On the other hand, at the end of the middle 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 the middle grinding, the thickness measurement method is switched during the middle grinding. Therefore, thickness monitoring becomes complicated.

According to the present 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 measurement of the second optical sensor OS2 is performed. Compared to the range, the range is wide, the lower limit is large, and the upper limit is large. Therefore, it is not necessary to switch the thickness measuring method during the middle 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 the middle grinding. Further, it is not necessary to switch the thickness measuring method even during the 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 the finish grinding. Therefore, it is possible to facilitate the monitoring of the thickness.

According to the present embodiment, the thickness HA (for example, 350 μm) of the first substrate W1 at the end of rough grinding and the start of medium grinding is within the measurement range of the first optical sensor OS1 (for example, in the range of 20 μm to 950 μm). (Inside). The thickness HA (for example, 100 μm) of the first substrate W1 at the end of the middle grinding and the start of the finish grinding is within the measurement range of the first optical sensor OS1 (for example, within the range of 20 μm to 950 μm), and the first 2 It is within the measurement range of the optical sensor OS2 (for example, within the range of 5 μm to 300 μm). Further, the thickness HA (for example, 10 μm) of the first substrate W at the end of finish grinding is smaller than the lower limit (for example, 20 μm) of the measurement range of the first optical sensor OS1, and the second optical sensor OS 2 and the third optical It is within the measurement range of the formula sensor OS3 (for example, within the range of 5 μm to 300 μm).

Next, the initial adjustment of the chuck 20 will be described. After the chuck 20 is attached to the rotary table 10, the chuck 20 is first ground by the grinding unit 30 in a state where the rotation center line R2 of the chuck 20 is tilted. As a result, the holding surface 21 of the chuck 20 becomes a conical surface symmetrical with respect to the rotation center line R2 of the chuck 20 as emphasized in FIG. 8 and the like.

After that, the substrate is ground while the substrate is held on the holding surface 21 of the chuck 20. Subsequently, the thickness of the substrate is measured at a plurality of points in the radial direction of the substrate, and the tilt angle adjusting unit 50 adjusts the tilt angle of the rotation center line R2 of the chuck 20 so that the deviation of the thickness is less than the threshold value. In addition to the adjustment of the inclination angle, as an initial adjustment, the holding surface 21 of the chuck 20 may be regrinded to improve the degree of adhesion between the mechanical parts.

The present inventor has found through experiments and the like that the initial adjustment can be easily carried out by using a single substrate instead of the polymerization substrate T. Since the distribution of the thickness HB of the remaining portion R of the polymerization substrate T is complicated, if the inclination angle is adjusted in consideration of the distribution, the calculation of the inclination angle becomes complicated and the reproducibility is low. Because it becomes.

In the present embodiment, a single substrate is used instead of the polymerization substrate T for the initial adjustment. The single substrate is, for example, a semiconductor substrate or a glass substrate, similarly to the first substrate W1. The thickness of a single substrate after finish grinding is measured by an optical sensor in the same manner as the thickness HA of the first substrate W1 after finish grinding. In the case of the optical type, the thickness of the substrate can be measured accurately even if the height of the optical head fluctuates when the optical head is moved in order to measure the thickness at a plurality of points.

This is because the optical sensor measures the thickness of the substrate from the waveform of the interference wave between the light reflected on the upper surface of the substrate and the light reflected on 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 interferometric 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 type head fluctuates when the contact type head is moved in order to measure the thickness at a plurality of points, the measured value of the thickness of the substrate also fluctuates.

Although the thickness HA of the first substrate W1 of the polymerization substrate T can be measured by the optical sensor, the total thickness HT of the polymerization substrate T cannot be measured. This is because the polymerization substrate T blocks light by the metal layers of the device layers D1 and D2. Since the total thickness HT of the polymerization substrate T cannot be measured by the optical sensor, the inclination angle cannot be adjusted from the deviation of the total thickness HT.

As described above, in the present embodiment, a single substrate is used instead of the polymerization substrate T for the initial adjustment. The method for grinding a single substrate is the same as the method for grinding a polymerized substrate T. However, the thickness of the single substrate after the finish grinding is set to be thicker than the thickness HA of the first substrate W1 of the polymerization substrate T after the finish grinding. This is because if the settings are set to the same level, the thickness of the single substrate after finish grinding will be too thin, and it will be difficult to transport the single substrate alone.

When grinding a single substrate, the target thickness in rough grinding, medium grinding, and finish grinding is set to be thicker than in the case of grinding the first substrate W1 of the polymerized substrate T. Therefore, when grinding a single substrate, a thickness measurement sensor having a different combination from that when grinding the first substrate W1 of the polymerized substrate T is used.

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

In step S2, the grinding unit 30-1 roughly grinds a single substrate. During rough grinding, the first contact sensor CS1 monitors changes in the thickness of a single substrate. The measurement range of the first contact type sensor CS1 is not particularly limited, but is, for example, 0 mm to 2 mm. When the thickness of the substrate reaches the set value, the grinding tool C for rough grinding is stopped 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 rotary table 10.

In step S3, the grinding unit 30-2 medium-grinds a single substrate. During medium grinding, the thickness of the substrate exceeds the upper limit of the measurement range of the first optical sensor OS1 (for example, 950 μm). Therefore, during the middle grinding, the second contact type sensor CS2 monitors the change in the 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 the set value, the grinding tool C for medium grinding is stopped descending and rises to the original standby position. After that, the single substrate moves from the middle grinding position A2 to the finish grinding position A3 by the rotation of the rotary table 10.

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

In step S5, the first optical sensor OS1 instead of the third optical sensor OS3 measures the thickness of a single substrate after finish grinding at a plurality of 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.

The measurement range of the third optical sensor OS3 is determined in consideration of the thickness HA of the first substrate W1 of the polymerization substrate T after finish grinding with respect to the polymerization 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 the single substrate after finish grinding is not particularly limited, but is, for example, about 500 μm from the viewpoint of transport, which is outside the measurement range of the third optical sensor OS3.

Therefore, instead of the third optical sensor OS3, the first optical sensor OS1 measures the thickness of a single substrate after finish grinding with 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 the range is wider than the measurement range of the third optical sensor OS3. (T1 _max -T1 _min > T3 _max -T3 _min ), 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 is within the measurement range of the first optical sensor OS1. Therefore, if the first optical sensor OS1 is used, the thickness of a single substrate after finish grinding can be measured at a plurality of points in the radial direction of the substrate.

After that, steps S6 to S8 are performed. In steps S7 to S8, the measurement result of the first optical sensor OS1 is used. If a single substrate is used instead of the polymerization substrate T, it is not necessary to take into account the complicated distribution of the thickness HB of the remaining portion R of the polymerization substrate T in the initial adjustment. Therefore, the initial adjustment is easy. Specifically, the calculation of the tilt angle is easy, and the reproducibility is high.

The initial adjustment is performed for each chuck 20. Steps S1 to S7 are carried out for each chuck 20. That is, for each chuck 20, grinding of a single substrate (for example, rough grinding, medium grinding, and finish grinding), measurement of the thickness of the substrate after finish grinding, and adjustment of the inclination angle of the rotation center line R2 of the chuck 20 are performed. Is carried out.

By the way, as is clear from comparing FIGS. 10 and 11, the single substrate is arranged at the middle grinding position A2 in step S5, unlike the polymerization substrate T. The single substrate moves from the finish grinding position A3 to the middle grinding position A2, and then further moves from the middle grinding position A2 to the loading / unloading position A0. As a result, the throughput of the grinding device 1 is reduced.

Therefore, as shown in FIG. 12, a single substrate may also be arranged at the carry-in / out position A0 in step S5, similarly to the polymerization substrate T. In this case, the single substrate is moved to the rough grinding position A1, the medium grinding position A2, the finish grinding position A3, and the loading / unloading position A0 in this order. Therefore, the throughput of the grinding device 1 can be improved.

Optical type connected to each other via an optical fiber in the case of grinding a single substrate and the case of grinding a polymerization substrate T in order to set the position of the single substrate in step S5 to the carry-in / out position A0. The combination of the sensor and the optical head may be switched. For example, as shown in FIG. 13, the first optical sensor OS1 is connected to the optical head LS3 arranged above the carry-in / out position A0 via the optical fiber OF3, and is a single substrate after finish grinding. The thickness is measured at multiple points in the radial direction of the substrate.

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

Although the grinding device and the grinding method according to the present disclosure have been described above, the present disclosure is not limited to the above-described embodiment and the like. Various changes, modifications, replacements, additions, deletions, and combinations are possible within the scope of the claims. Of course, they also belong to the technical scope of the present disclosure.

1 Grinding device 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 2nd optical sensor W1 1st substrate

Claims (14)

The chuck that holds the board and
A pre-grinding unit that pre-grinds the substrate before finish grinding,
A first optical sensor that measures the thickness of the substrate during the pre-grinding,
A finish grinding unit that finish grinds the substrate and
A second optical sensor that measures the thickness of the substrate during the finish grinding,
A moving mechanism for moving the chuck between the pre-grinding position and the finish grinding position.
Equipped with
The measurement range of the first optical sensor partially overlaps with the measurement range of the second optical sensor, and the range is wider than the measurement range of the second optical sensor. A grinding device with a large lower limit and a large upper limit. Further, a third optical sensor for measuring the thickness of the substrate after the finish grinding at a plurality of radial points of the substrate is provided.
The measurement range of the first optical sensor partially overlaps with the measurement range of the third optical sensor, and the range is wider than the measurement range of the third optical sensor. The grinding apparatus according to claim 1, wherein the lower limit value is large and the upper limit value is large. When the substrate is held by the chuck in a state of being joined to the second substrate, the thickness of the substrate after the finish grinding is measured by the third optical sensor at a plurality of radial points of the substrate.
The second aspect of the present invention, wherein when the substrate is held by the chuck in a single piece state, the thickness of the substrate after the finish grinding is measured by the first optical sensor at a plurality of radial points of the substrate. Grinding equipment. The moving mechanism moves the chuck between the pre-grinding position, the finish grinding position, and the position carried out by the transport device.
When the substrate is held by the chuck in a single piece state, when the first optical sensor measures the thickness of the substrate after the finish grinding at a plurality of points in the radial direction of the substrate, the substrate is used. The grinding apparatus according to claim 3, which is arranged at the carrying-out position. The moving mechanism moves the chuck between the pre-grinding position, the finish grinding position, and the position carried out by the transport device.
When the substrate is held by the chuck in a single piece state, when the first optical sensor measures the thickness of the substrate after the finish grinding at a plurality of points in the radial direction of the substrate, the substrate is used. The grinding apparatus according to claim 3, which is arranged at the position for pre-grinding. An inclination angle adjusting unit that adjusts the inclination angle of the rotation center line of the chuck,
A control unit that controls the tilt angle adjustment unit is provided.
The control unit adjusts the inclination angle of the rotation center line of the chuck so that the thickness of the substrate after the finish grinding in a single piece state becomes uniform, according to any one of claims 3 to 5. The grinding device described. When the substrate is held by the chuck in a state of being joined to the second substrate, the first optical sensor measures the thickness of the substrate during the pre-grinding, and the second optical sensor is the finish. The grinding apparatus according to any one of claims 1 to 6, wherein the thickness of the substrate is measured during grinding. Holding the board with a chuck and
Pre-grinding and pre-grinding the substrate before finish grinding
During the pre-grinding, the thickness of the substrate is measured by the first optical sensor, and
The finish grinding of the substrate and
During the finish grinding, the thickness of the substrate is measured by the second optical sensor, and
The chuck includes moving the chuck between the pre-grinding position and the finish grinding position.
The measurement range of the first optical sensor partially overlaps with the measurement range of the second optical sensor, and the range is wider than the measurement range of the second optical sensor. , A grinding method with a large lower limit and a large upper limit. The thickness of the substrate after the finish grinding includes measuring the thickness of the substrate at a plurality of radial points of the substrate by a third optical sensor.
The measurement range of the first optical sensor partially overlaps with the measurement range of the third optical sensor, and the range is wider than the measurement range of the third optical sensor. The grinding method according to claim 8, wherein the lower limit value is large and the upper limit value is large. When the substrate is held by the chuck in a state of being joined to the second substrate, the thickness of the substrate after the finish grinding is measured by the third optical sensor at a plurality of radial points of the substrate. ,
When the substrate is held by the chuck in a single piece state, the thickness of the substrate after the finish grinding is measured by the first optical sensor at a plurality of radial points of the substrate. The grinding method according to claim 9. The chuck includes moving the chuck between a position for pre-grinding, a position for finish grinding, and a position for carrying out by a transfer device.
When the substrate is held by the chuck in a single piece state, when the first optical sensor measures the thickness of the substrate after the finish grinding at a plurality of points in the radial direction of the substrate, the substrate is used. The grinding method according to claim 10, which is arranged at the carry-out position. The chuck includes moving the chuck between a position for pre-grinding, a position for finish grinding, and a position for carrying out by a transfer device.
When the substrate is held by the chuck in a single piece state, when the first optical sensor measures the thickness of the substrate after the finish grinding at a plurality of points in the radial direction of the substrate, the substrate is used. The grinding method according to claim 10, which is arranged at the pre-grinding position. The invention according to any one of claims 10 to 12, which comprises adjusting the inclination angle of the rotation center line of the chuck so that the thickness of the substrate after the finish grinding becomes uniform in a single sheet state. Grinding method. When the substrate is held by the chuck in a state of being joined to the second substrate, the first optical sensor measures the thickness of the substrate during the pre-grinding, and the second optical sensor is the finish. The grinding method according to any one of claims 8 to 13, wherein the thickness of the substrate is measured during grinding.

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