JP2002280332A - Polishing method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make small wave-like warpages, which are generated when both surfaces of a thin and disk-like work, such as a semiconductor wafer, are polished. SOLUTION: In both sides of a work rotating and supporting drive mechanism 40 for supporting the thin and disk-like work W, the reference axis and a pressurizing axis 35 are allocated coaxially and both surfaces of the work are polished with a reference side for rotating disk 24 and a pressurizing side rotating disk 34 provided at end portions of the reference axis and pressurizing axis. The relative rotational direction, between each surface of work and the processing surface of each rotating disk placed in contact with the surface, may be switched during the polishing process; and this switching may be done by reversing the rotating direction of work, by reversing the rotating directions of the rotating disks, or by taking out the work from the area between both rotating disks, and then reversing the surfaces of the work and inserting the work again between both rotating disks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a polishing method and a polishing apparatus for simultaneously performing polishing such as lapping or polishing on both surfaces of a thin disk-shaped workpiece such as a semiconductor wafer.

[0002]

2. Description of the Related Art For example, when polishing both surfaces of a thin disk-shaped workpiece such as a semiconductor wafer by lapping or the like, the ends of a reference axis and a pressure axis which are coaxially arranged are attached to each other. The reference side rotating disk and the pressurizing side rotating disk provided opposite to each other are rotated in opposite directions, and the work is sandwiched between the two rotating disks and supported in one direction. The slurry containing abrasive grains is supplied between the objects, and the pressing-side rotating disk is pressed toward the reference-side rotating disk. This polishing is performed from the start of processing to the end of processing without changing the rotation direction of each rotating disk and the workpiece.

[0003]

However, a workpiece polished by the above-mentioned prior art has a problem that a slight warp as shown in FIG. 13 is generated. This warpage is thought to be caused by the difference in relative speed between each surface of the workpiece and the processing surface of each rotating disk,
The relationship between the direction of rotation of the workpiece and each of the rotating disks and the direction of the warpage of the generated waveform is as shown in FIG.
Note that the workpiece shape in each case shown in FIG. 11 shows the surface on the pressure shaft side as the upper side. FIG. 11 shows a case where the shape of the workpiece before processing is a flat surface. If the shape of the workpiece before processing is generally in the shape of an arc, if the workpiece is polished, as shown in FIG. Figure 1 on a bowed sled
1 has a shape in which the warpage of the waveform is superimposed. In any case, the warpage of the waveform increases according to the length of the polishing time.

An object of the present invention is to reduce such a warp of a waveform by devising a polishing method and a polishing apparatus.

[0005]

To this end, a polishing method according to the present invention comprises inserting a thin disk-shaped workpiece between a reference side rotating disk and a pressing side rotating disk, rotating the workpiece, and rotating the workpiece. In the polishing method of rotating the rotating disks in directions opposite to each other and urging the pressing-side rotating disk toward the reference-side rotating disk to grind each surface of the workpiece with the processing surface at the tip of each rotating disk, during the polishing process In addition, the relative rotation direction between each surface of the workpiece and the processing surface of each rotating disk that comes into contact with the workpiece is switched.

[0006] Switching of the relative rotational direction in the polishing method according to the present invention is preferably performed by reversing the rotational direction of the workpiece.

The switching of the relative rotational direction in the polishing method according to the present invention may be performed by reversing the rotational direction of each rotary disk.

In the polishing method according to the present invention, the relative rotation direction is switched by first taking out the workpiece from between the two rotating disks, inverting the two surfaces of the workpiece so that they are interchanged, and then switching between the two rotating disks. It may be performed by inserting again.

It is preferable that the switching of the relative rotation direction in the polishing method according to any one of the preceding aspects be performed after a predetermined polishing processing time has elapsed.

The switching of the relative rotation direction in the polishing method of the preceding invention is performed when the thickness of the polished workpiece reaches a predetermined value, instead of when a predetermined polishing time has elapsed. Is also good.

Further, the polishing apparatus according to the present invention is a work rotation drive mechanism for rotating a thin disk-shaped work rotatably supported by the work rotation support device, and is supported by the work rotation support device. A reference axis that is arranged on one side of the workpiece and that is provided at the tip and rotationally drives and is positioned at a predetermined position in the axial direction, and is provided at the tip and disposed coaxially with the reference axis on the other side of the workpiece. It consists of a pressing shaft that rotates the pressing-side rotating disk in the opposite direction to the reference-side rotating disk and urges it toward the reference-side rotating disk, and grinds each surface of the workpiece with the processing surface at the end of each rotating disk. The polishing apparatus is characterized in that the polishing apparatus is provided with a control device for switching a relative rotation direction between each surface of the workpiece and a processing surface of each rotating disk that comes into contact with the surface during polishing.

It is preferable that the control device in the polishing apparatus according to the present invention switches the relative rotational direction by reversing the rotational drive direction of the workpiece by the workpiece rotational drive mechanism.

The control device in the polishing apparatus according to the present invention may switch the relative rotation direction by reversing the rotation direction of each rotating disk by the reference axis and the pressing axis.

Further, the polishing apparatus according to the present invention further comprises a manipulator having a hand portion for detachably holding the workpiece, and the control device holds the workpiece by the hand portion of the manipulator and controls both rotating disks. The relative rotation direction may be switched by temporarily removing the workpiece from the space, reversing the two surfaces of the workpiece so that they are exchanged with each other, and then inserting the workpiece again between the two rotating disks.

It is preferable that the control device in the polishing apparatus according to the fourth aspect of the invention switches the relative rotation direction when a predetermined polishing time has elapsed.

The polishing apparatus according to the above-mentioned invention further comprises a thickness sizing device for measuring the thickness of the workpiece, and the control device replaces the thickness when a predetermined polishing time has elapsed. The relative rotation direction may be switched when the thickness of the workpiece measured by the sizing device reaches a predetermined value.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a description will be given of a case where a polishing method and a polishing apparatus according to the present invention are applied to lapping processing according to a first embodiment shown in FIGS. This first
The lapping apparatus according to the embodiment is a semiconductor wafer W having a thin disk shape (for example, a thickness of less than 1 mm and a diameter of about 300 mm).
And a wafer rotation support device (workpiece rotation support device) 49, as shown in FIGS.
And a wafer rotation drive mechanism (workpiece rotation drive mechanism) 40
A reference axis 25 provided on one side of a wafer (workpiece) W supported by a wafer rotation support device 49 and having a reference side lap surface plate (reference side rotating disk) 24 provided at a tip thereof; Pressing shaft 3 provided coaxially with reference shaft 25 on the other side and provided with a press-side lap surface plate (pressing-side rotating disk) 34 at the tip
5 and a control device 10 for controlling the operation of these parts 25, 35, 40, 49 and the like.

The wafer rotation support device 49 is supported on a bed (not shown) of the lapping device, and has four support rollers 4 for supporting the outer peripheral portion of the wafer W as shown in FIG.
9a and 49b are provided. Four support rollers 49a,
The upper two (49b) of the wafers 49b can reciprocate along a straight line in the radial extension direction of the wafer W or along an arc centered on the axis 49c. When the support roller 49b is retracted, the wafer W can be attached and detached. When the support roller 49b is advanced, the wafer W is rotatably supported.

As shown in FIGS. 1 and 2, the wafer rotation driving mechanism 40 has a pair of a driving roller 42a and a driven roller 42b sandwiching the outer peripheral edge of the wafer W. The driving roller 42a is rotatably driven by a servomotor 44 for driving a wafer while being supported by a bearing block 43a fixed on a support table (not shown). The driven roller 42b includes a movable bearing block 43 provided on a support base so as to be movable in parallel with the axis of the support rollers 49a and 49b.
b, the movable bearing block 43b can be biased by the pressing cylinder 45 toward the fixed bearing block 43a. Activating the pressing cylinder 45 to drive the drive roller 42a
When the drive roller 42a is rotationally driven by the wafer drive motor 44 with the wafer W interposed between the wafer W and the driven roller 42b, the wafer W supported by the support rollers 49a and 49b is rotated.
Is driven to rotate.

The reference shaft 25 includes a reference shaft casing 26 supported by the reference shaft table 20, a reference rotation shaft 27 rotatably supported by the reference shaft casing 26, and a built-in reference shaft motor 28 for driving the rotation. And on one side of the wafer W supported by the support rollers 49a and 49b,
The wafer W is eccentrically arranged parallel to the rotation axis of the wafer W. The reference axis table 20 is guided and supported in a reciprocable manner in parallel with the rotation axis of the wafer W via a linear guide 21 supported on a bed of the lapping apparatus, and reciprocates by a feed device 22 including a servomotor 22a and a screw shaft 22b. Is done. A reference-side lapping plate 24 having a diameter slightly larger than the radius of the wafer W is coaxially fixed to the tip of the reference-side rotation shaft 27 on the wafer W side.

The pressing shaft 35 includes a pressing shaft casing 36,
It comprises a pressurizing-side rotating shaft 37 rotatably supported by this, and a built-in pressurizing-shaft motor 38 for rotationally driving the pressurizing-side rotating shaft 37. I have. The pressurizing shaft casing 36 is guided and supported by a pressurizing shaft housing 30 fixed to the bed via a stroke ball 31 so as to reciprocate in parallel with the rotation axis of the wafer W. It is urged toward. A press-side lap plate 34 having the same diameter as the reference-side lap plate 24 is coaxially fixed to the tip of the press-side rotary shaft 37 on the wafer W side. As a result, it is driven to rotate in a direction opposite to the reference side lap surface plate 24.

As shown in FIG. 1, the control device 10 for controlling the operation of the lapping device comprises a central processing unit (CPU) and a memory.
2a and the reference shaft motor 28,
Of the pressurizing syringe 32 and the pressurizing shaft motor 3
8 to control the operation of the pressure shaft 35, the wafer drive motor 44 and the pressing cylinder 45 to control the operation of the wafer rotation drive mechanism 40, the wafer rotation support device 49, etc. This controls the operation of. The memory stores software for controlling the lapping device, data for each wafer to be processed, measured data, and the like. The controller 10 is connected to an input / output device 11 for manually controlling the wrapping device and updating data in a memory.

Next, an example of the operation of the above-described lapping apparatus according to the first embodiment will be described with reference to the operation explanatory view of FIG. 4, the change in the warp of the wafer of FIG. 5, and the flowchart of FIG. In this example, the rotation direction of the wafer W is switched only once during the lapping process.

When the wrapping device is started by the input / output device 11, the control device 10 first sets the normal rotation time and the reverse rotation time of the wafer W (step 100). The lapping processing time required to obtain a predetermined thickness from a material of a wafer W obtained by cutting a semiconductor cylindrical ingot into a thin disk shape by wire cutting, excluding surface irregularities and a deteriorated layer, is experimentally obtained in advance. The half of the lapping time is defined as a normal rotation time and a reverse rotation time, respectively. Next, the control device 10 retreats the reference shaft 25, the pressure shaft 35, and the two support rollers 49b, and carries in and out the driven roller 42b of the wafer rotation support device 49 with the driven roller 42b separated from the drive roller 42a. The wafer W is carried into the wafer rotation support device 49 by an apparatus (not shown), inserted between the reference lap plate 24 and the pressure lap plate 34, and each support roller 49b is advanced to advance the wafer W. Is supported by the four support rollers 49a and 49b (step 10).
1).

Next, the control device 10 operates the servo motor 22a of the feed device 22 to advance the reference shaft 25,
When the reference side lap plate 24 is positioned at a predetermined position in the axial direction, the reference shaft 25 is stopped, and the pressurizing cylinder 32 is operated via the sequencer 12 to move the wafer W to the reference side lap plate 24 and the press side lap plate. It is clamped between the boards 34 at a predetermined pressure (step 102). In this state, the processing surface serving as the front surface of the reference side lapping plate 24 is aligned with the contact line of the drive roller 42a of the wafer rotation drive mechanism 40 with the wafer W. Around the end of the clamping of the wafer W by the two lap plates 24 and 25, the control device 10
Operates the pressing cylinder 45 of the wafer rotation drive mechanism 40 to sandwich the outer peripheral edge of the wafer W between the driving roller 42a and the driven roller 42b.
The drive roller 42a is rotated forward by the wafer drive motor 44 so as to rotate forward (a direction that is clockwise when viewed from the left side in FIG. 1).
4 and the pressure side lapping plate 34 rotate in the reverse and forward directions, respectively.
(Refer to FIG. 4A) (step 10).
3). At the same time, a slurry containing abrasive grains is supplied between each lapping plate 24, 34 and the wafer W from a hole (not shown) formed at the center of each of the rotating shafts 27, 37, FIG. 4 (a) until the turning time elapses.
Is performed (step 10).
4).

If the primary lapping time of the wafer W exceeds the normal rotation time, the controller 10 stops the wafer drive motor 44, the reference axis motor 28, and the pressure axis motor 38, and sets the wafer W and both laps. The rotation of the boards 24, 34 is stopped (step 105). Next, the control device 1
0 indicates that the drive roller 42a is rotated in reverse by the wafer drive motor 44 so that the wafer W is rotated in reverse, and the reference axis motor 28 and the pressure axis are rotated so that the respective lap plates 24 and 34 rotate and rotate in the same manner as in step 103. Motor 38
(Refer to FIG. 4B) (step 10).
6). Thus, the secondary lapping process shown in FIG. 4B is performed until the reverse rotation time set in step 101 elapses (step 107).

When the secondary lapping time of the wafer W exceeds the reverse rotation time, the controller 10 stops the wafer drive motor 44, the reference axis motor 28, and the pressure axis motor 38, and stops the wafer W and both lap plates. The rotation of 24, 34 is stopped, the reference shaft 25 is retracted by the servo motor 22a of the feeder 22, the pressure shaft 35 is retracted by the pressure cylinder 32, and the driven roller 42b of the wafer rotation drive mechanism 40 is retracted. Then, the holding of the wafer W by the rollers 42a and 42b is released (step 108). Then, the control device 10 retreats the two support rollers 49b,
The wafer W on which the lapping process is completed is carried out between the support rollers 49a and 49b by the carry-in / out device (Step 109).

The material of the thin disk-shaped wafer W from which the wire has been cut causes a warp of a waveform as shown by a dashed line a in FIG. 5 by the primary lapping process. If the secondary lapping is performed without changing the rotation direction of the boards 24 and 34, the warpage of the waveform continues to increase and becomes large as shown by the dashed line b. However, in the first embodiment, the rotation direction of the wafer W in the secondary lapping process is switched to the direction opposite to that of the primary lapping process.
The relative rotation direction between each of the surfaces and the processing surface at the tip of each of the lap plates 24 and 34 in contact therewith is also switched in the opposite direction. Accordingly, the relative speed of the processing surface at the tip of each lap surface plate 24, 34 with respect to each surface of the wafer W is switched between the primary lapping process and the secondary lapping process. The direction of the progress is opposite to the direction of the primary lapping process. Therefore, the warp of the waveform as shown by the broken line a generated in the primary lapping process progresses in the opposite direction in the secondary lapping process and becomes smaller as shown by the two-dot chain line c. It is smaller than before. FIG. 5 shows a case where the shape of the wafer before processing is a flat surface. However, if the shape of the wafer before processing is generally in the shape of an arc, if lapping is performed, FIG. As shown in the figure, only the arc-shaped warp is superimposed with the wave-shaped warp shown in FIG. 5, and the warp remaining after the completion of the secondary lapping process is still smaller than in the conventional case.

In the first embodiment, the switching between the primary lapping process and the secondary lapping process can be performed simply by reversing the rotation direction of the wafer W. This switching can be performed very easily and quickly. However, the productivity does not decrease as compared with the related art.

In the first embodiment, half of the time required for lapping the material of the wafer W cut into a thin disk into a predetermined thickness is defined as a normal rotation time and a reverse rotation time, respectively. Switching direction is 1
It is performed only once, but this embodiment is not limited to this,
The rotation direction may be switched three times with each forward rotation time and reverse rotation time being set to １ ／ of the total time required for lapping. Alternatively, the forward rotation time and the reverse rotation time may be set to values obtained by dividing the total time required for the lapping process by an even number of 6 or more, and the number of rotation direction switching may be set to a value corresponding thereto.

In the first embodiment, the rotation direction of the wafer W is switched in the opposite direction. However, instead of the wafer W, the rotation direction of each of the lap plates 24 and 34 is switched in the opposite direction. You may. Also in this case, the relative rotation direction between each surface of the wafer W and the processing surface at the tip of each of the lapping plates 24 and 34 in contact therewith is switched to the opposite direction. Is reversed in the direction of the primary lapping, and the effect that the warp remaining after the completion of the secondary lapping is reduced as compared with the conventional case is obtained. Also in this case, the switching of the rotation direction of each of the lap plates 24 and 34 can be performed very easily and quickly, so that the effect that the productivity does not decrease as compared with the conventional case can be obtained. A groove is usually formed on the processing surface at the tip of each of the lap plates 24, 34 in order to make the dispersion of the slurry containing abrasive grains uniform. In the case of this switching variant, a directional groove, such as a vortex line, is inappropriate for the direction of rotation, and it is necessary to select such a non-directional groove.

Next, a second embodiment of the present invention will be described with reference to a flowchart shown in FIG. The wrapping device used in the second embodiment includes a thickness sizing device 15 for measuring the thickness of the wafer W as shown by a two-dot chain line in FIG. Instead of switching the rotation direction of the wafer W when the primary lapping processing time has passed a predetermined forward rotation time as in the embodiment, the thickness of the wafer W measured by the thickness sizing device 15 is changed to a predetermined value. When the value reaches the value, the rotation direction of the wafer W is switched,
The lapping process is stopped when the target value is reached. Since other configurations are the same as those of the first embodiment, only the operation will be described with reference to a flowchart.

When the wrapping device is started by the input / output device 11, the control device 10 first sets the finished thickness Tt corresponding to the wafer W (step 200). Next, the control device 10 carries the wafer W into the wafer rotation support device 49 and carries out the reference-side lap plate 24 and the pressure-side lap plate 3 in the same manner as in step 101 of the first embodiment.
4 (step 201), the upper support rollers 49b are advanced to support the wafer W by the wafer rotation support device 49, and then the reference side lap plate 24 is at a predetermined position in the axial direction. The reference shaft 25 is advanced and stopped as described above (step 202).

Next, the control device 10 controls the rotation shafts 27 and 3
The slurry containing abrasive grains is discharged from a hole formed at the center of the wafer 7, and at the same time, the pressing cylinder 45 of the wafer rotation drive mechanism 40 is operated to move the outer peripheral edge of the wafer W to the drive roller 42a and the driven roller 42b. Then, the pressure cylinder 32 is operated to hold the wafer W between the reference-side lapping plate 24 and the pressure-side lapping plate 34 at a low predetermined pressure (step 203). Then, the drive roller 42 is driven by the wafer drive motor 44 so that the wafer W rotates forward.
Then, the reference shaft motor 28 and the pressurizing shaft motor 38 are operated so as to rotate the motor a in the forward direction and to rotate the reference side lap plate 24 and the press side lap plate 34 in the reverse and forward directions, respectively (step 204). In this state, the control device 10 measures the thickness T0 of the wafer W at the start of the processing by the thickness sizing device 15 (step 205), and the processing allowance ΔT (= T1−T0).
Is calculated (step 206). And pressurizing cylinder 3
The primary lapping process in a state where the wafer W is normally rotated is started by setting the pressing force of the pressure side lap surface plate 34 by the pressure 2 to a predetermined high pressure (step 207).

During the primary lapping process, the controller 10 measures the thickness T of the wafer W by the thickness sizing device 15 as needed, and until the processing is performed by half the processing allowance ΔT (that is, T ≦ T1). + ΔT / 2) in step 207
(Step 208), and after this, the rotation of each of the lap plates 24 and 34 is temporarily stopped (Step 209), and the wafer drive motor 44 is rotated in the reverse direction to rotate the wafer W in the reverse direction (Step 210). , Each lap surface plate 2
4 and 34 are again rotated in the same direction
Next lapping processing is started (step 211). The control device 10 performs the reversing process of Step 211 until the thickness T of the wafer W measured by the thickness sizing device 15 reaches the finished thickness Tt (that is, while T ≦ T1) (Step 212). When the finished thickness Tt is reached, the reverse rotation of the wafer W is stopped, and the rotation of each of the lap plates 24, 34 is also stopped (step 213). Next, the control device 10
Stops the supply of the slurry, the reference shaft 25 and the pressurizing shaft 3
5 is retracted, the two support rollers 49b of the wafer rotation support device 49 are retracted, and the driven roller 42b of the wafer rotation drive mechanism 40 is retracted, and both rollers 42a, 42b are retracted.
Release the wafer W from being held (step 21)
4). Then, the control device 10 uses the loading / unloading device to transfer the wafer W having completed the lapping process to the supporting rollers 49a, 4a.
9b (step 215).

Also in the second embodiment, the rotation direction of the wafer W in the secondary lapping process is switched to the direction opposite to that of the primary lapping process. Since the relative speed of the processing surface at the tip is switched between the primary lapping and the secondary lapping, the warp of the waveform generated by the primary lapping is reduced by the secondary lapping. Further, since the switching between the primary lapping process and the secondary lapping process is performed only by reversing the rotation direction of the wafer W, this switching can be performed very easily and quickly, and the productivity is not reduced as compared with the conventional case. Absent. Further, in the second embodiment, since the thickness of the wafer W can be directly controlled, the accuracy of the thickness of the wrapped wafer W is improved.

In the second embodiment, half of the total machining allowance is used as the primary lapping work and the secondary lapping work, respectively, and the rotation direction of the wafer W is switched only once. This embodiment is not limited to this, and switching of the rotation direction may be performed three times, with 1/4 of the processing allowance as the processing allowance for the first to fourth lapping. Alternatively, as the value obtained by dividing the machining allowance by an even number of 6 or more, the number of times of rotation direction switching may be set to a value corresponding thereto.

Next, a third embodiment shown in FIGS. 8 to 10 will be described. In the third embodiment, the rotation directions of the wafer W and the lapping plates 24 and 34 are not switched, and the wafer W is moved from between the lapping plates 24 and 34.
Is different from the first embodiment only in that it is once taken out, inverted so that both surfaces of the wafer W are exchanged with each other, and then inserted again between the two lap plates 24 and 34. This difference will be described.

The lapping apparatus according to the third embodiment has a manipulator 50 for taking out, inverting, and inserting a wafer W, and the first embodiment is different from the first embodiment except that the specific control contents of the controller 10 are different. This is the same as the embodiment. As shown in FIG. 8, the manipulator 50 has a hand portion 51 at the tip thereof, and the hand portion 51 is provided with three suction cups 52 for holding the wafer W by suction in a triangular shape. . Specific control contents of the control device 10 for controlling the operation of the lapping device are as described in the operation of the lapping device described below.

Next, an example of the operation of the wrapping device according to the third embodiment will be described with reference to the operation explanatory diagram of FIG. 9 and the flowchart of FIG. In this example, the wafer W is taken out and inverted only once during the lapping process.

When the lapping device is started by the input / output device 11, the control device 10 sets the primary lapping time and the secondary lapping time of the wafer W in the same manner as in step 100 of the first embodiment. (Step 300). Next, the control device 10 uses the suction cup 52 of the hand unit 51 of the manipulator 50 to control the thin disk-shaped wafer W
The material is sucked and held, and is carried into a wafer rotation support device 49, and the reference side lap plate 24 and the pressure side lap plate 34 are placed.
, And is supported by four support rollers 49a and 49b, and the suction by the suction cup 52 is released.
1 is retracted (step 301). During this time, the wafer rotation support device 49 and the wafer rotation drive mechanism 4
The operation of 0 is the same as in the first embodiment. Subsequent steps 302 to 304 are substantially the same as steps 102 to 104 of the first embodiment. Until the primary lapping processing time set in step 300 elapses, the steps shown in FIG. Next lapping is performed (step 304). The rotation directions of the wafer W and the respective lap plates 24 and 34 are normal rotation of the wafer W, reverse rotation of the reference side lap plate 24 and normal rotation of the pressurization lap plate 34 (see FIG. 9A). .

When the primary lapping time of the wafer W has elapsed, the controller 10 stops the rotation of the wafer W and both lapping plates 24 and 34, as in the first embodiment (step 305). The reference shaft 25 is retracted by the servo motor 22a of the feed device 22,
Causes the pressure shaft 35 to retreat (step 306). Next, the control device 10 inserts the hand portion 51 of the manipulator 50 into the wafer rotation support device 49, holds the wafer W by the suction cup 52, and retracts the two support rollers 49b. The wafer W is once taken out as shown by a two-dot chain line WA in FIG. 8, and is inverted by 180 degrees so that both surfaces of the wafer W are interchanged. Then, the hand portion 51 of the manipulator 50 is advanced again, and the wafer W is loaded into the wafer rotation support device 49 and inserted again between the reference side lap plate 24 and the pressure side lap plate 34,
Each support roller 49b is advanced to support the wafer W by the four support rollers 49a and 49b, the suction by the suction cup 52 is released, and the hand unit 51 is retracted (step 307). The following steps 308 to 310
This is substantially the same as the above-described steps 302 to 304, and the secondary lapping shown in FIG. 9C is performed until the secondary lapping time set in step 300 elapses (step 310).

After the secondary lapping time of the wafer W has elapsed, the control device 10 stops the rotation of the wafer W and both lapping plates 24 and 34 and the reference shaft 25 as in the first embodiment. And the pressure shaft 35 is retracted (step 311), and the two support rollers 49b are retracted,
Similar to step 307, the hand unit 5 of the manipulator 50
1 is advanced into the wafer rotation support device 49 and the suction cup 52 is moved.
, The two support rollers 49b are retracted, and the lapping-completed wafer W is carried out between the support rollers 49a and 49b (step 3).
12).

In the third embodiment, the wafer W is always rotated forward, the reference side lapping plate 24 is rotated in the reverse direction, and the pressure side lapping plate 34 is rotated in the normal direction. Since the wafer W is inverted by 180 degrees between and, each lap surface plate 24 for each surface of the wafer W,
Since the relative speed of the processing surface at the tip of 34 is switched between the primary lapping process and the secondary lapping process, as in the first embodiment, the direction of the progress of the warp of the waveform generated by the wafer W by the secondary lapping process is as follows. The direction is opposite to that of the primary lapping process. Therefore, the warp of the waveform as shown by the broken line a in FIG. 5 caused by the primary lapping process proceeds in the opposite direction in the secondary lapping process and becomes smaller as shown by the two-dot chain line c. The remaining warpage is smaller than before.

Further, in the third embodiment, the wafer W is reduced by one in the primary lapping process and the secondary lapping process.
The surface wrapped by the primary lapping process on the processing surface of the reference side lapping plate 24 is wrapped by the processing surface of the pressure side lapping plate 34 in the secondary lapping process, and the primary lapping process is performed. Pressing side lap surface plate 34
In the secondary lapping process, the surface wrapped by the processed surface is wrapped by the processed surface of the reference side lap surface plate 24. Although the processing conditions of the processing surface at the tip of the reference side lap surface plate 24 and the processing surface at the tip of the pressure side lap surface plate 34 are slightly different,
In the third embodiment, since the respective surfaces of the wafer W are wrapped by the respective lapping plates 24 and 34 for the same time, the difference in the processing conditions is canceled out, and therefore, the respective surfaces of the wrapped wafer W are removed. The accuracy is improved.

As in the case of the second embodiment, the present invention is provided with a thickness sizing device 15 for measuring the thickness of the wafer W. When the next lapping processing time has passed a predetermined normal rotation time, the thickness of the wafer W measured by the thickness sizing device 15 has reached a predetermined value instead of taking out the wafer W, inverting it, and inserting it again. Occasionally, the wafer W may be taken out, inverted, inserted again, and the lapping process may be stopped when the target value is reached. By doing so, the accuracy of the thickness of the wrapped wafer W is improved.

In the third embodiment, as in the first embodiment, the reversal of the wafer W can be performed a plurality of times. However, the process of taking out the wafer W with the manipulator 50, inverting the wafer W, and inserting it again requires a considerable time. Therefore, as long as productivity is considered, the inversion of the wafer W is performed only once as described above. Is good.

[0048]

According to the polishing method of the present invention, the relative rotation direction between each surface of the workpiece and the processing surface of each rotating disk that comes into contact with the workpiece is switched during the polishing, whereby the waveform of the workpiece is changed. The traveling direction of the sled is reversed before and after the switching of the relative rotation direction. Therefore, once generated and increased warpage decreases after switching the relative rotation direction,
The warpage remaining after the polishing process is smaller than before.

In the polishing method of the present invention, the relative rotation direction is switched by reversing the rotation direction of the workpiece, and the rotation directions of the respective rotating disks are all reversed. According to the method described above, since the switching of the relative rotation direction can be performed quickly, the productivity is not reduced as compared with the related art.

Further, in the polishing method of the present invention, the workpiece is once taken out from between the two rotating disks, turned over so that both surfaces of the workpiece are interchanged, and then inserted again between the two rotating disks. According to the configuration in which the rotation direction is switched, each surface of the workpiece is polished by the reference-side rotating disk and the pressing-side rotating disk having slightly different processing conditions, thereby offsetting the difference in the processing conditions. Therefore, the accuracy of the surface of the polished workpiece is improved.

According to the polishing method of the above-mentioned inventions, the switching of the relative rotation direction is performed when a predetermined polishing processing time has elapsed. Therefore, the method can be easily performed without requiring any special equipment. be able to.

According to the polishing method of the preceding invention, the relative rotation direction is switched when the thickness of the polished workpiece reaches a predetermined value. The accuracy of the thickness of the object is improved.

According to the polishing apparatus of the present invention, the relative rotation direction between each surface of the workpiece and the processing surface of each rotating disk abutting on the surface is switched by the control device during polishing.
Thereby, the traveling direction of the warp of the workpiece is reversed before and after the switching of the relative rotation direction. Therefore, the warpage once generated and increased is reduced after the switching of the relative rotation direction, and the warpage remaining after the polishing is completed is smaller than that of the related art.

In the polishing apparatus of the present invention, the relative rotation direction is switched by the control device by reversing the rotation direction of the workpiece, and the rotation direction of each rotating disk is reversed. According to the method described above, the switching of the relative rotation direction can be performed promptly, so that the productivity is not reduced as compared with the related art.

Further, in the polishing apparatus of the present invention, the control device holds the workpiece by the hand portion of the manipulator, temporarily removes the workpiece from between the two rotating disks, and inverts both surfaces of the workpiece so that they are exchanged with each other. According to the configuration in which the relative rotation direction is switched by re-inserting between the rotating disks, each surface of the workpiece is polished by the reference-side rotating disk and the pressing-side rotating disk, which have slightly different processing conditions. Thus, the difference in the processing conditions is offset, so that the accuracy of the surface of the polished workpiece is improved.

According to the polishing apparatus of the above-mentioned inventions, the switching of the relative rotation direction by the control device is performed when a predetermined polishing processing time elapses. Can be implemented.

According to the polishing apparatus of the above-mentioned invention, the relative rotation direction is switched by the control device when the thickness of the polished workpiece reaches a predetermined value. The accuracy of the thickness of the finished workpiece is improved.

[Brief description of the drawings]

FIG. 1 is a view showing an overall configuration of a polishing apparatus used in a first embodiment of a polishing method according to the present invention.

FIG. 2 is a plan view showing mechanical components of the polishing apparatus shown in FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a perspective view illustrating an operation of the polishing method according to the first embodiment.

FIG. 5 is a view for explaining a temporal change of a warp of a thin disk-shaped workpiece polished by this type of polishing apparatus.

FIG. 6 is a flowchart illustrating the operation of the first embodiment.

FIG. 7 is a flowchart illustrating the operation of the second embodiment.

FIG. 8 is a sectional view corresponding to FIG. 3 of a third embodiment of the polishing apparatus according to the present invention.

FIG. 9 is a perspective view illustrating an operation of a polishing method according to a third embodiment.

FIG. 10 is a flowchart illustrating the operation of the third embodiment.

FIG. 11 is a view for explaining the operation state of this type of polishing apparatus and the state of warpage of a thin disk-shaped workpiece to be polished thereby.

FIG. 12 is a diagram for explaining a temporal change of a warp of a thin disk-shaped workpiece polished by a polishing apparatus of this type according to the related art.

FIG. 13 is a view for explaining a state of warpage of a thin disk-shaped workpiece polished by this type of polishing apparatus.

[Explanation of symbols]

Reference Signs List 10 ... Control device, 15 ... Thickness sizing device, 24 ... Reference-side rotating disk (reference-side lapping plate), 25 ... Reference axis, 34 ... Pressing-side rotating disk (pressing-side lap surface plate), 35 ... Pressure Axis 4
0: Workpiece rotation drive mechanism (wafer rotation drive mechanism), 4
9 Workpiece rotation support device (wafer rotation support device), 5
0: Manipulator, 51: Hand unit, W: Workpiece (wafer).

Continued on the front page (72) Inventor Morito Abe 1-1-1, Asahi-cho, Kariya-shi, Aichi Prefecture Toyota Machine Works F-term (reference) 3C058 AA09 AA11 AA12 AA14 AA16 AB01 AB03 AB04 AC04 BA02 BA07 BA09 BB06 BB09 CB02 DA17

Claims (12)

[Claims] 1. A thin disk-shaped workpiece is inserted between a reference side rotating disk and a pressing side rotating disk, and the workpiece is rotated to rotate the two rotating disks in opposite directions and to rotate the pressing side rotating disk. In a polishing method for polishing each surface of the workpiece by a processing surface at the tip of each rotating disk by urging the disk toward the reference side rotating disk, each surface of the workpiece during polishing and A polishing method characterized by switching the relative rotation direction between the processing surfaces of the rotating disks that come into contact with each other. 2. The polishing method according to claim 1, wherein the switching of the relative rotation direction is performed by reversing a rotation direction of the workpiece. 3. The polishing method according to claim 1, wherein the switching of the relative rotation direction is performed by reversing the rotation direction of each of the rotating disks. 4. The polishing method according to claim 1, wherein the switching of the relative rotation direction is such that the workpiece is temporarily taken out from between the two rotating disks, and the workpiece is reversed so that both surfaces of the workpiece are switched with each other. A polishing method which is performed by inserting the disk between the rotating disks again. 5. The polishing method according to any one of claims 1 to 4, wherein the switching of the relative rotation direction includes:
A polishing method, which is performed when a predetermined polishing time has elapsed. 6. The polishing method according to any one of claims 1 to 4, wherein the switching of the relative rotation direction includes:
A polishing method, which is performed when the thickness of the polished workpiece reaches a predetermined value. 7. A workpiece rotation drive mechanism for rotating and driving a thin disk-shaped workpiece rotatably supported by a workpiece rotation support device, and one of the workpieces supported by the workpiece rotation support device. A reference shaft that is arranged on the side and is driven to rotate and rotates the reference-side rotating disk and is positioned at a predetermined position in the axial direction. The rotating disk is driven in the opposite direction to the reference-side rotating disk and comprises a pressurizing shaft that urges the rotating disk toward the reference-side rotating disk. Each surface of the workpiece is polished by a processing surface at the tip of each rotating disk. A polishing apparatus for processing, comprising: a control device for switching a relative rotation direction between each surface of the workpiece and a processing surface of each rotating disk that comes into contact with the surface during polishing. 8. The polishing apparatus according to claim 7, wherein the control device switches the relative rotation direction by reversing a rotational drive direction of the workpiece by the workpiece rotation drive mechanism. A polishing apparatus, comprising: 9. The polishing apparatus according to claim 7, wherein the control device reverses the rotation direction of each of the rotating disks by the reference axis and the pressing axis, thereby changing the relative rotation direction. A polishing apparatus characterized by switching. 10. The polishing apparatus according to claim 7, wherein
The controller further includes a manipulator having a hand unit that detachably holds the workpiece, the control device holds the workpiece by a hand unit of the manipulator, temporarily removes the workpiece from between the two rotating disks, and removes the workpiece. The polishing apparatus is characterized in that the relative rotation direction is switched by reversing the two surfaces so that they are exchanged with each other and then reinserting them between the two rotating disks. 11. The polishing apparatus according to claim 7, wherein the control device switches the relative rotation direction when a predetermined polishing processing time has elapsed. Characteristic polishing equipment. 12. The polishing apparatus according to claim 7, further comprising a thickness sizing device for measuring the thickness of the workpiece, wherein the control device is configured to control the thickness of the workpiece. The polishing apparatus according to claim 1, wherein the relative rotation direction is switched when the thickness of the workpiece measured by a sizing device reaches a predetermined value.