JP2020196079A - Method of processing workpiece - Google Patents

Abstract

To provide a method of processing a workpiece that can efficiently form a cross section of a corner part of the workpiece.SOLUTION: A method of processing a workpiece includes a grinding step ST11 of forming a circular recessed part and a ring-shaped projection part by grinding a central part of a reverse surface of the workpiece held on a holding table with a grinding wheel, a moving step ST12 of relatively moving the grinding wheel and the holding table to a position where a rotation path of a grinding grindstone passes through the ring-shaped projection part after performing the grinding step ST11, a cross section forming step ST13 of forming a cross section of a ring-shaped projection part by grinding the ring-shaped projection part by at least a height of the ring-shaped projection part or more with the grinding wheel without rotating the holding table and with the grinding wheel rotating after performing the moving step ST12, and a shape verifying step ST14 of verifying a shape of a corner part formed by a bottom surface of a circular recessed part and an inner peripheral surface of a ring-shaped projection part by imaging or observing the cross section.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for processing a workpiece.

A technique for thinning the workpiece by grinding only the inner circumference thereof while leaving the outermost peripheral end portion of the workpiece, that is, a so-called TAIKO (registered trademark) grinding technique is known (Patent Document 1). reference).

Japanese Unexamined Patent Publication No. 2012-146888

In TAIKO (registered trademark) grinding, if the corner portion formed by the inner peripheral surface of the ring-shaped convex portion and the circular concave portion in the workpiece is close to a right angle, cracks are likely to occur. Therefore, in order to prevent cracks from easily forming in the corners of the workpiece, an arc shape, that is, an R shape is formed in the corners of the workpiece. The arcuate shape of the corner portion of the workpiece is usually formed by grinding the grinding wheel in a state where the corner portion of the grinding wheel is rounded due to wear on the outer peripheral side in contact with the workpiece. However, when the machining load is high or the grinding wheel is brittle, the grinding wheel is chipped during grinding and the grinding wheel is ground with the corners not rounded, so the corners of the workpiece may be at right angles. .. In addition, if the grinding wheel is chipped multiple times, the corners of the workpiece may form a right-angled step.

Therefore, it is required to see the shape of the corner portion of the workpiece. Conventionally, in order to see the shape of the corners of the work piece, the work piece after TAIKO (registered trademark) grinding is cut and split with a diamond cutter, and the work piece after TAIKO (registered trademark) grinding is cut with a dicer. There is a problem that it takes time and effort to form the cross section of the corner portion of the workpiece, such as exposing the cross section.

The present invention has been made in view of such problems, and an object of the present invention is to provide a processing method for a work piece capable of more efficiently forming a cross section of a corner portion of the work piece. ..

In order to solve the above-mentioned problems and achieve the object, the processing method of the workpiece of the present invention includes a holding table that rotatably holds the workpiece and a plurality of grinding wheels that are rotatably held by the spindle. It is a method of processing a work piece using a grinding wheel equipped with a grinding wheel and a processing apparatus equipped with the above method, wherein the central portion of the back surface of the work piece held on the holding table is ground by the grinding wheel. A grinding step that forms a circular concave portion and a ring-shaped convex portion that surrounds the circular concave portion, and after the grinding step is performed, the grinding wheel and the holding table are formed, and the rotation trajectory of the grinding wheel forms the ring-shaped convex portion. A moving step that moves relative to a passing position, and after the moving step is performed, the holding table is not rotated and the grinding wheel is rotated, and the ring-shaped convex portion is at least the ring with the grinding wheel. A cross-section forming step of grinding above the height of the ring-shaped convex portion to form a cross section of the ring-shaped convex portion, and imaging or observing the cross section, the bottom surface of the circular concave portion and the inner peripheral surface of the ring-shaped convex portion are formed. It is characterized by including a shape confirmation step for confirming the shape of the corner portion to be formed.

According to the present invention, the cross section of the corner portion of the workpiece can be formed more efficiently.

FIG. 1 is a flowchart showing a processing method of a workpiece according to the first embodiment. FIG. 2 is a perspective view showing one state of the grinding step of FIG. FIG. 3 is a top view showing one state of the grinding step of FIG. FIG. 4 is a top view showing one state of the moving step and the cross-sectional forming step of FIG. FIG. 5 is a perspective view showing one state of the shape confirmation step of FIG. FIG. 6 is a cross-sectional view showing an example of a state of a corner portion of the workpiece confirmed in the shape confirmation step of FIG. FIG. 7 is a top view showing one state of the moving step and the cross-section forming step in the processing method of the workpiece according to the second embodiment. FIG. 8 is a perspective view showing one state of the shape confirmation step in the processing method of the workpiece according to the second embodiment.

An embodiment (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Further, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions or changes of the configuration can be made without departing from the gist of the present invention.

[Embodiment 1]
The processing method of the workpiece according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart showing a processing method of a workpiece according to the first embodiment. FIG. 2 is a perspective view showing one state of the grinding step ST11 of FIG. FIG. 3 is a top view showing one state of the grinding step ST11 of FIG. FIG. 4 is a top view showing one state of the moving step ST12 and the cross-sectional forming step ST13 of FIG. FIG. 5 is a perspective view showing one state of the shape confirmation step ST14 of FIG. FIG. 6 is a cross-sectional view showing a state example of the corner portion 113 (see FIG. 5) of the workpiece confirmed in the shape confirmation step ST14 of FIG.

As shown in FIG. 1, the method for processing the workpiece according to the first embodiment includes a grinding step ST11, a moving step ST12, a cross-section forming step ST13, and a shape confirmation step ST14.

As shown in FIG. 2, the work piece 100 to be processed by the work piece processing method according to the first embodiment is a disk-shaped semiconductor having silicon, sapphire, gallium arsenide, or the like as a substrate in the present embodiment. Wafers such as wafers and optical device wafers. The workpiece 100 includes a device region in which a device is formed on the surface 101, and an outer peripheral surplus region surrounding the device region. A protective tape 103 that protects the surface 101 of the workpiece 100 is attached to the surface 101.

In the processing method of the workpiece according to the first embodiment, the central portion of the back surface 102 of the workpiece 100 is ground by the processing apparatus 10 which is the grinding apparatus shown in FIG. 2, and the circular recess 111 and the circular recess 111 are surrounded. This is a method of confirming the shape of the corner portion 113 formed by the bottom surface of the circular concave portion 111 and the inner peripheral surface of the ring-shaped convex portion 112 after forming the ring-shaped convex portion 112. As shown in FIG. 2, the processing apparatus 10 that executes the processing method for the workpiece according to the first embodiment is rotatable on a holding table 11 that rotatably holds the workpiece 100 on the holding surface 12 and a spindle 15. A grinding wheel 17 which is held by and has a plurality of grinding wheels 16 is provided.

The holding table 11 has a holding surface 12 along the XY plane, and the holding surface 12 holds the surface 101 side of the workpiece 100 via the protective tape 103. That is, the holding table 11 holds the workpiece 100 so that the back surface 102 side opposite to the front surface 101 side is the exposed surface. The holding table 11 is rotated in a predetermined direction around the axis along the Z-axis direction by a rotation drive mechanism (not shown).

The plurality of grinding wheels 16 forming the grinding wheel 17 are screwed to a mounter fixed to the tip of the spindle 15 and arranged in an annular shape at equal intervals. Although eight grinding wheels 16 are shown in FIG. 2 and the like, the present invention is not limited thereto. In the grinding wheel 17, the grinding surfaces formed by the plurality of grinding wheels 16 are arranged so as to face the holding surface 12 in the Z-axis direction. The grinding wheel 17 is rotated around the axis along the Z-axis direction in a direction opposite to the rotation direction of the holding table 11 by a rotation drive mechanism (not shown). The grinding wheel 17 rotates in a state of being in contact with the back surface 102 of the workpiece 100 held on the holding table 11, so that the workpiece 100 is annularly formed on the back surface 102 based on the arrangement of the plurality of grinding wheels 16. Grind from the side.

The holding table 11 and the grinding wheel 17 are each provided with a moving mechanism (not shown), and the moving mechanism relatively moves the holding table 11 and the grinding wheel 17 along the XY plane direction and the Z-axis direction. That is, the grinding surface of the grinding wheel 17 moves relative to the holding surface 12 of the holding table 11 along the XY plane direction and the Z-axis direction by this moving mechanism.

As shown in FIGS. 2 and 3, in the grinding step ST11, the central portion of the back surface 102 of the workpiece 100 held on the holding table 11 by the grinding wheel 17 is ground, and the circular recess 111 and the circular recess 111 are formed. This is a so-called TAIKO (registered trademark) grinding step, which is a step of forming a ring-shaped convex portion 112 that surrounds the ring.

Specifically, in the grinding step ST11, first, the grinding surface of the grinding wheel 17 is moved relative to the holding surface 12 of the holding table 11 along the XY plane direction by the moving mechanism, so that FIG. 3 shows. As shown, the end portion of the grinding wheel 17 on the outer peripheral side of the grinding surface is arranged at a position in contact with the outer peripheral circle of the circular recess 111 to be formed.

In the grinding step ST11, the grinding surface of the grinding wheel 17 is then moved along the Z-axis direction relative to the holding surface 12 of the holding table 11 by the moving mechanism, as shown in FIG. The grinding surface of the grinding wheel 17 is brought into contact with the central portion of the back surface 102 of the workpiece 100 held by the holding table 11.

In the grinding step ST11, and as shown in FIGS. 2 and 3, the rotation drive mechanism rotates the holding table 11 to rotate the workpiece 100 on the holding surface 12, and also holds the grinding wheel 17 on the holding table. It is rotated to the opposite side of the 11 and further moved by the moving mechanism in the grinding feed direction in which the grinding surface of the grinding wheel 17 is relatively close to the holding surface 12 of the holding table 11 in the Z-axis direction. As a result, in the grinding step ST11, the central portion of the back surface 102 of the work piece 100 is ground by the grinding wheel 17 to form the circular recess 111, and the work piece that is not ground due to the formation of the circular recess 111. The outer peripheral portion of the back surface 102 of the 100 remains to form the ring-shaped convex portion 112.

In the grinding step ST11, it is preferable to form the circular recess 111 in the region of the back surface 102 corresponding to the device region of the front surface 101, and to form the ring-shaped convex portion 112 in the region of the back surface 102 corresponding to the outer peripheral surplus region.

As shown in FIG. 4, the moving step ST12 relatively moves the grinding wheel 17 and the holding table 11 to a position where the rotation trajectory of the grinding wheel 16 passes through the ring-shaped convex portion 112 after the grinding step ST11 is performed. It is a step.

In the moving step ST12, specifically, the moving mechanism inscribes the rotation trajectory of the grinding wheel 16 in the grinding wheel 17 with the outer circle of the circular recess 111 formed in the workpiece 100 held on the holding table 11. From the position (the position after the execution of the grinding step ST11), along the XY plane direction, toward the radial outside of the holding table 11 relative to the holding table 11, the diameter of the rotating track of the grinding wheel 16 By moving a short distance, the rotating track of the grinding wheel 16 is moved to a position where it crosses the ring-shaped convex portion 112.

In the cross-section forming step ST13, after the moving step ST12 is performed, the ring-shaped convex portion 112 is at least the height of the ring-shaped convex portion 112 on the grinding wheel 17 in a state where the holding table 11 is not rotated and the grinding wheel 17 is rotated. This is a step of grinding to form a cross section 121 (see FIG. 5) of the ring-shaped convex portion 112.

Specifically, in the cross-section forming step ST13, the holding table 11 is not rotated, the grinding wheel 17 is rotated, and the circular concave portion 111 and the ring-shaped convex portion 112 are ground by the grinding wheel 17, as shown in FIG. As described above, the ring-shaped convex portion 112 is crossed, and an arc-shaped groove 120 that follows the rotation trajectory of the grinding wheel 16 is formed in an annular shape based on the arrangement of the plurality of grinding wheels 16. As a result, in the cross-section forming step ST13, the cross-section 121 is formed on the side surface portion of the arc-shaped groove 120 that crosses the region of the corner portion 113 formed by the inner peripheral surface of the ring-shaped convex portion 112 and the circular concave portion 111.

In the shape confirmation step ST14, as shown in FIGS. 5 and 6, the cross section 121 formed in the cross section forming step ST13 is imaged or observed, and the bottom surface of the circular concave portion 111 and the inner peripheral surface of the ring-shaped convex portion 112 are formed. This is a step of confirming the shape of the corner portion 113.

Specifically, in the shape confirmation step ST14, as shown in FIG. 5, by using the observation imaging device 20 to image the cross section 121 formed in the cross section forming step ST13, the captured image of the cross section 121 is acquired. , The shape of the corner portion 113 is confirmed based on the acquired image of the cross section 121. Alternatively, in the shape confirmation step ST14, the shape of the corner portion 113 is confirmed based on the observation image of the cross section 121 by observing the cross section 121 formed in the cross section forming step ST13 by using the observation imaging device 20.

The observation imaging device 20 is an eyepiece that allows an operator to observe an observation image of the cross section 121 via an objective lens directed to a cross section 121 including a corner portion 113 that is symmetrical in shape confirmation, an objective lens, and a predetermined optical system. A lens, an imaging element that captures an image of a cross section 121 via an objective lens and a predetermined optical system to obtain an image, and predetermined optics that can switch the destination of an optical path from the objective lens between the eyepiece and the imaging element. Has a system and. In the predetermined optical system, the destination of the optical path from the objective lens can be appropriately switched by the control device 21 exemplified by the computer electrically connected to the observation imaging device 20 so as to be able to communicate information.

In the shape confirmation step ST14, for example, the cross section 121-1 as shown in FIG. 6 (A), the cross section 121-2 as shown in FIG. 6 (B), and FIG. 6 (C) are used by using the observation imaging device 20. ) Is obtained as an image taken or observed with a cross section 121-3.

In the shape confirmation step ST14, when the cross section 121-1 is obtained, it is confirmed that the shape of the corner portion 113 is an arc shape, that is, an R shape 123. In the shape confirmation step ST14, further, based on the confirmation result, it can be determined that the workpiece 100 has a circular concave portion 111 and a ring-shaped convex portion 112 having a preferable shape, and the grinding wheel in use. It can be determined that the corner portion of the grinding wheel 16 of 17 is in a sound state with a rounded shape.

In the shape confirmation step ST14, when the cross section 121-2 is obtained, it is confirmed that the shape of the corner portion 113 is a right-angled shape 124. In the shape confirmation step ST14, further, based on this confirmation result, it can be determined that the workpiece 100 does not have the circular concave portion 111 and the ring-shaped convex portion 112 having a preferable shape, and the grinding wheel in use. It can be determined that the corner portion of the grinding wheel 16 of 17 is not rounded and is in a right-angled unhealthy state.

In the shape confirmation step ST14, when the cross section 121-3 is obtained, it is confirmed that the shape of the corner portion 113 is a right-angled stepped 125. In the shape confirmation step ST14, further, based on this confirmation result, it can be determined that the workpiece 100 does not have the circular concave portion 111 and the ring-shaped convex portion 112 having a preferable shape, and the grinding wheel in use. It can be determined that the corner portion of the grinding wheel 16 of 17 is not rounded and is in a right-angled stepped unhealthy state.

Each confirmation process and determination process in the shape confirmation step ST14 is to store the analysis processing standard of the captured image and the confirmation standard and the determination standard in the control device 21 in advance, and the control device 21 automatically executes them. May be.

In the processing method of the workpiece according to the first embodiment, the grinding wheel 16 is rotated by shifting the relative position between the grinding wheel 17 and the holding table 11 from the time when the grinding step ST11 is executed in the moving step ST12. The orbit forms a relative positional relationship through the ring-shaped convex portion 112, and in the cross-section forming step ST13, the cross-section 121 of the corner portion 113 formed by the bottom surface of the circular concave portion 111 and the inner peripheral surface of the ring-shaped convex portion 112 is formed. Therefore, the processing method of the workpiece according to the first embodiment is a laborious work for forming the cross section 121 of the corner portion 113, such as cutting and splitting with a diamond cutter or cutting with a dicer to expose the cross section. The corner of the workpiece 100 is more efficient in terms of time and man-hours by using only the grinding function of the processing device 10 that executes the so-called TAIKO (registered trademark) grinding process without requiring The cross section 121 of the portion 113 can be formed.

Further, in the processing method of the workpiece according to the first embodiment, in the moving step ST12, the rotational trajectory of the grinding wheel 16 is moved to a position where it crosses the ring-shaped convex portion 112, and in the cross-sectional forming step ST13, the ring-shaped convex portion 112 An arc-shaped groove 120 that follows the rotation trajectory of the grinding wheel 16 is formed in an annular shape based on the arrangement of the plurality of grinding wheels 16. Therefore, in the processing method of the workpiece according to the first embodiment, the direction of the cross section 121 formed in the cross section forming step ST13 is close to the direction orthogonal to the direction of the inner peripheral surface of the ring-shaped convex portion 112. As a result, the processing method of the workpiece according to the first embodiment takes time and effort to form the cross section 121 of the corner portion 113, such as cutting and splitting with a conventional diamond cutter or cutting with a dicer to expose the cross section. Since it is possible to form a cross section 121 in a direction close to the cross section obtained through various operations, it is possible to confirm and judge using a conventional confirmation standard for the shape of the corner portion 113 or a standard similar to the judgment standard. ..

[Embodiment 2]
The processing method of the workpiece according to the second embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a top view showing one state of the moving step ST12 and the cross-section forming step ST13 in the processing method of the workpiece according to the second embodiment. FIG. 8 is a perspective view showing one state of the shape confirmation step ST14 in the processing method of the workpiece according to the second embodiment. In FIGS. 7 and 8, the same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The processing method of the workpiece according to the second embodiment is a modification of the moving step ST12 in the processing method of the workpiece according to the first embodiment. In the moving step ST12 according to the first embodiment, the moving step ST12 according to the second embodiment moves the rotating track of the grinding wheel 16 to a position where it crosses the ring-shaped convex portion 112, as shown in FIG. This is a step of moving the end of the rotary track of the grinding wheel 16 to a position where it partially overlaps the ring-shaped convex portion 112.

In the cross-section forming step ST13 according to the second embodiment, as shown in FIG. 8, the end portion is partially overlapped with the ring-shaped convex portion 112 due to the change of the moving step ST12, and is based on the arrangement of the plurality of grinding wheels 16. In an annular shape, an arc-shaped groove 130 that follows the rotation trajectory of the grinding wheel 16 is formed. As a result, in the cross-section forming step ST13 according to the second embodiment, the cross-section 131 is formed on the side surface portion of the arc-shaped groove 130 that crosses the region of the corner portion 113.

The processing method of the workpiece according to the second embodiment is the same as the processing method of the workpiece according to the first embodiment, in the moving step ST12 and the cross-section forming step ST13, the bottom surface of the circular recess 111 and the ring-shaped convex portion 112. A cross section 121 of the corner portion 113 formed by the inner peripheral surface is formed. Therefore, the method for processing the workpiece according to the second embodiment has the same effect as the method for processing the workpiece according to the first embodiment.

Further, in the processing method of the workpiece according to the second embodiment, in the moving step ST12, the end portion of the rotary track of the grinding wheel 16 is moved to a position where it partially overlaps with the ring-shaped convex portion 112, and in the cross section forming step ST13. , The end portion is partially overlapped with the ring-shaped convex portion 112, and an arc-shaped groove 130 following the rotation trajectory of the grinding wheel 16 is formed in an annular shape based on the arrangement of the plurality of grinding wheels 16. Therefore, in the processing method of the workpiece according to the second embodiment, the direction of the cross section 131 formed in the cross section forming step ST13 is close to the direction of the inner peripheral surface of the ring-shaped convex portion 112. Therefore, the method for processing the workpiece according to the second embodiment is easier because the observation imaging device 20 can be easily directed and the cross section 131 that can be easily imaged and observed can be formed by using the observation imaging device 20. In the work, the shape of the corner portion 113 can be confirmed and various determinations can be made.

The present invention is not limited to the above embodiment. That is, it can be modified in various ways without departing from the gist of the present invention.

10 Processing equipment 11 Holding table 15 Spindle 16 Grinding wheel 17 Grinding wheel 100 Work piece 102 Back surface 111 Circular concave part 112 Ring-shaped convex part 113 Square part 120, 130 Groove 121, 131 Cross section

Claims (1)

A method for processing an workpiece using a processing apparatus provided with a holding table for rotatably holding the workpiece and a grinding wheel rotatably held by a spindle and equipped with a plurality of grinding wheels.
A grinding step in which the central portion of the back surface of the workpiece held on the holding table is ground by the grinding wheel to form a circular concave portion and a ring-shaped convex portion surrounding the circular concave portion.
After performing the grinding step, a moving step of relatively moving the grinding wheel and the holding table to a position where the rotation trajectory of the grinding wheel passes through the ring-shaped convex portion,
After performing the moving step, the ring-shaped convex portion is ground at least at least the height of the ring-shaped convex portion by the grinding wheel in a state where the holding table is not rotated and the grinding wheel is rotated. A cross-section forming step for forming a cross-section of a convex portion,
A shape confirmation step of imaging or observing the cross section to confirm the shape of the corner portion formed by the bottom surface of the circular concave portion and the inner peripheral surface of the ring-shaped convex portion.
A method for processing a work piece, which comprises.

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