JP7233308B2 - Workpiece processing method - Google Patents

Description

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

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

JP 2012-146889 A

In TAIKO (registered trademark) grinding, if the corner formed by the inner peripheral surface of the ring-shaped protrusion and the circular recess in the workpiece is close to a right angle, cracks are likely to occur. Therefore, in order to prevent cracks from forming in the corners of the workpiece, the corners of the workpiece are formed into an arc shape, that is, an R shape. The arc shape of the corner portion of the workpiece is usually formed by grinding in a state where the corner portion of the grinding wheel is rounded due to wear of the outer peripheral side of the grinding wheel in contact with the workpiece. However, if the processing load is high or the grinding wheel is fragile, the grinding wheel may be chipped during grinding, and the corners of the workpiece may be squared because the corners of the grinding wheel are not rounded. . Also, if the grinding wheel is chipped several times, the corners of the workpiece may become stepped at right angles.

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

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to provide a method of processing a workpiece that can more efficiently form a cross-section of a corner portion of the workpiece. .

In order to solve the above-described problems and achieve the object, a method for machining a workpiece according to the present invention includes a holding table for rotatably holding a workpiece, and a plurality of grinding wheels rotatably held by a spindle. and a grinding wheel comprising a grinding step of forming a circular recess and a ring-shaped projection surrounding the circular recess; a moving step of relatively moving the ring-shaped protrusion to a position through which the ring-shaped projection passes at least the ring with the grinding wheel while the holding table is not rotated and the grinding wheel is rotated after performing the moving step; A step of forming a cross-section of the ring-shaped protrusion by grinding at least the height of the ring-shaped protrusion, and imaging or observing the cross-section so that the bottom surface of the circular recess and the inner peripheral surface of the ring-shaped protrusion are and a shape confirmation step of confirming the shape of the formed corner portion.

The present invention can more efficiently form the cross section of the corner portion of the workpiece.

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

A form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by 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. Furthermore, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions, or changes in configuration can be made without departing from the gist of the present invention.

[Embodiment 1]
A method for processing a workpiece according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart showing a method for processing a workpiece according to Embodiment 1. FIG. 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-section 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 an example of the state of the corner portion 113 (see FIG. 5) of the workpiece confirmed in the shape confirmation step ST14 of FIG.

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

As shown in FIG. 2, a workpiece 100 to be processed by the method for machining a workpiece according to the first embodiment is a disk-shaped semiconductor substrate made of silicon, sapphire, gallium arsenide, or the like. It is a wafer such as a wafer or an optical device wafer. A workpiece 100 has a device region in which a device is formed on a surface 101 and an outer peripheral marginal region surrounding the device region. The workpiece 100 has a surface 101 to which a protective tape 103 is attached to protect the surface 101 .

In the method for processing a workpiece according to the first embodiment, the processing apparatus 10, which is a grinding apparatus shown in FIG. After forming the ring-shaped projection 112 , the shape of the corner portion 113 formed by the bottom surface of the circular recess 111 and the inner peripheral surface of the ring-shaped projection 112 is confirmed. As shown in FIG. 2, a processing apparatus 10 for executing the method for processing a workpiece according to the first embodiment includes a holding table 11 that rotatably holds a workpiece 100 on a holding surface 12 and a spindle 15 that can rotate. a grinding wheel 17 with a plurality of grinding wheels 16 held therein.

The holding table 11 has a holding surface 12 along the XY plane, and holds the surface 101 side of the workpiece 100 via the protective tape 103 on the holding surface 12 . 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 an exposed surface. The holding table 11 is rotated in a predetermined direction about an axis along the Z-axis direction by a rotation drive mechanism (not shown).

A plurality of grinding wheels 16 forming a grinding wheel 17 are screwed to a mounter fixed to the tip of the spindle 15 and arranged in a ring at regular intervals. Although eight grinding wheels 16 are shown in FIG. 2 and the like, the present invention is not limited to this. The grinding wheel 17 is arranged such that the grinding surfaces formed by the plurality of grinding wheels 16 face the holding surface 12 in the Z-axis direction. The grinding wheel 17 rotates in a direction opposite to the rotation direction of the holding table 11 about an axis along the Z-axis direction by a rotation drive mechanism (not shown). The grinding wheel 17 rotates in contact with the back surface 102 of the workpiece 100 held on the holding table 11 , thereby circularly grinding the workpiece 100 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 are relatively moved along the XY plane direction and the Z-axis direction by this moving mechanism. That is, the grinding surface of the grinding wheel 17 moves relatively along the XY plane direction and the Z-axis direction with respect to the holding surface 12 of the holding table 11 by this moving mechanism.

In the grinding step ST11, as shown in FIGS. 2 and 3, the central portion of the back surface 102 of the workpiece 100 held on the holding table 11 is ground by the grinding wheel 17 to form a circular concave portion 111 and a circular concave portion 111. This is the so-called TAIKO (registered trademark) grinding step, which forms the surrounding ring-shaped projection 112 .

Specifically, in the grinding step ST11, first, by moving the grinding surface of the grinding wheel 17 relative to the holding surface 12 of the holding table 11 along the XY plane direction by the moving mechanism, the grinding surface shown in FIG. As shown, the outer edge of the grinding surface of the grinding wheel 17 is placed in contact with the outer circumference of the circular recess 111 to be formed.

In the grinding step ST11, the moving mechanism moves the grinding surface of the grinding wheel 17 relative to the holding surface 12 of the holding table 11 along the Z-axis direction. 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 on the holding table 11 .

In the grinding step ST11, as shown in FIGS. 2 and 3, the rotary drive mechanism rotates the holding table 11 to rotate the workpiece 100 on the holding surface 12 and the grinding wheel 17 to the holding table. 11, and the moving mechanism moves the grinding surface of the grinding wheel 17 relatively to the holding surface 12 of the holding table 11 in the Z-axis direction in the grinding feed direction. As a result, in the grinding step ST11, the central portion of the back surface 102 of the workpiece 100 is ground by the grinding wheel 17 to form the circular recess 111, and the workpiece that is not ground as the circular recess 111 is formed. The outer peripheral portion of the back surface 102 of 100 remains to form a ring-shaped convex portion 112 .

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

In the moving step ST12, as shown in FIG. 4, after the grinding step ST11 is performed, the grinding wheel 17 and the holding table 11 are relatively moved to a position where the rotational trajectory of the grinding wheel 16 passes through the ring-shaped protrusion 112. is a step.

Specifically, in the moving step ST12, the rotating orbit of the grinding wheel 16 on the grinding wheel 17 is inscribed in the outer circumference of the circular concave portion 111 formed in the workpiece 100 held on the holding table 11 by the moving mechanism. From the position (the position after performing the grinding step ST11), along the XY plane direction, toward the radial direction outside of the holding table 11 relative to the holding table 11, the diameter of the rotation orbit of the grinding wheel 16 By moving the grinding wheel 16 by a short distance, the rotary orbit of the grinding wheel 16 is moved to a position where it traverses the ring-shaped projection 112 .

In the cross-section forming step ST13, after the moving step ST12 is performed, the ring-shaped protrusion 112 is moved to at least the height of the ring-shaped protrusion 112 by the grinding wheel 17 while the holding table 11 is not rotated and the grinding wheel 17 is rotated. This is the step of grinding to form the cross section 121 (see FIG. 5) of the ring-shaped projection 112 .

Specifically, in the cross-section forming step ST13, the grinding wheel 17 is rotated without rotating the holding table 11, and the circular concave portion 111 and the ring-shaped convex portion 112 are ground by the grinding wheel 17, thereby obtaining the shape shown in FIG. , an arc-shaped groove 120 is formed across the ring-shaped protrusion 112 and follows the rotational orbit of the grinding wheel 16 in an annular manner based on the arrangement of the plurality of grinding wheels 16 . Thus, in the cross-section forming step ST13, a cross-section 121 is formed on the side surface portion of the arc-shaped groove 120 crossing the area of the corner portion 113 formed by the inner peripheral surface of the ring-shaped protrusion 112 and the circular recess 111 .

In the shape confirmation step ST14, as shown in FIGS. 5 and 6, the cross section 121 formed in the cross section formation 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 the step of confirming the shape of the corner portion 113 .

In the shape confirmation step ST14, specifically, as shown in FIG. , the shape of the corner portion 113 is confirmed based on the acquired captured 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 observed image of the cross section 121 by observing the cross section 121 formed in the cross section formation step ST13 using the observation imaging device 20.

Note that the observation imaging device 20 includes an objective lens directed toward a cross section 121 including the corner portion 113 that is symmetrical for shape confirmation, and an eyepiece that allows an operator to observe an observation image of the cross section 121 through the objective lens and a predetermined optical system. a lens, an imaging element that obtains an imaged image by imaging a cross section 121 through an objective lens and a predetermined optical system, and predetermined optics that can switch the destination of the optical path from the objective lens between the eyepiece and the imaging element and a system. The predetermined optical system can appropriately switch the destination of the optical path from the objective lens by a control device 21 exemplified by a computer electrically connected to the observation imaging device 20 so as to be able to communicate information.

In the shape confirmation step ST14, using the observation imaging device 20, for example, a cross section 121-1 as shown in FIG. 6A, a cross section 121-2 as shown in FIG. ), a captured image or an observed image of the cross section 121-3 is obtained.

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, ie, an R shape 123. FIG. In the shape confirmation step ST14, further, based on this confirmation result, it can be determined that the workpiece 100 has the circular concave portion 111 and the ring-shaped convex portion 112 with preferable shapes. It can be determined that the grinding wheel 16 of 17 is in a healthy state with rounded corners.

In the shape confirmation step ST14, it is confirmed that the shape of the corner portion 113 is a right angle 124 when the cross section 121-2 is obtained. In the shape confirmation step ST14, further, based on the confirmation result, it can be determined that the workpiece 100 is not formed with the circular concave portion 111 and the ring-shaped convex portion 112 having the preferable shape, and the grinding wheel in use can be determined. It can be determined that the corner portion of the grinding wheel 16 of 17 is not rounded and is in an unhealthy right-angled 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 stepped shape 125 with right angles. In the shape confirmation step ST14, further, based on the confirmation result, it can be determined that the workpiece 100 is not formed with the circular concave portion 111 and the ring-shaped convex portion 112 having the preferable shape, and the grinding wheel in use can be determined. It can be determined that the corner portion of the grinding wheel 16 of 17 is not rounded and is in an unhealthy state of right-angled steps.

Note that each confirmation process and determination process in the shape confirmation step ST14 are performed automatically by the control device 21 by storing the captured image analysis processing criteria, confirmation criteria, and determination criteria in advance. may be

In the method for processing a workpiece according to the first embodiment, in the moving step ST12, the relative positions of the grinding wheel 17 and the holding table 11 are shifted from when the grinding step ST11 is executed, so that the grinding wheel 16 rotates. A relative positional relationship is formed in which the trajectory passes through the ring-shaped protrusion 112, and in a cross-section forming step ST13, a cross-section 121 of the corner portion 113 formed by the bottom surface of the circular recess 111 and the inner peripheral surface of the ring-shaped protrusion 112 is formed. For this reason, the method of processing a workpiece according to the first embodiment requires time-consuming 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 can be cut more efficiently in terms of time and man-hours by using only the grinding processing function of the processing device 10 that performs so-called TAIKO (registered trademark) grinding processing without requiring A cross-section 121 of portion 113 can be formed.

Further, in the method for processing a workpiece according to the first embodiment, in the moving step ST12, the rotation orbit of the grinding wheel 16 is moved to a position that crosses the ring-shaped convex portion 112, and in the cross-section forming step ST13, the ring-shaped convex portion 112 is moved. , and circular arc-shaped grooves 120 are formed along the rotation trajectory of the grinding wheels 16 based on the arrangement of the plurality of grinding wheels 16 . Therefore, in the method for processing a 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 eliminates the trouble of forming 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 such work, it is possible to confirm and judge using the same reference as the conventional confirmation standard of the shape of the corner portion 113 and the judgment standard. .

[Embodiment 2]
A method for processing a workpiece according to Embodiment 2 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 method for processing a workpiece according to the second embodiment. FIG. 8 is a perspective view showing one state of the shape checking step ST14 in the method for processing a workpiece according to the second embodiment. In addition, FIG.7 and FIG.8 attach|subjects the same code|symbol to the same part as Embodiment 1, and abbreviate|omits description.

The method for machining a workpiece according to the second embodiment is the same as the method for machining a workpiece according to the first embodiment, except that the moving step ST12 is changed. In the moving step ST12 according to the second embodiment, in place of moving the grinding wheel 16 to a position where the rotation track of the grinding wheel 16 traverses the ring-shaped convex portion 112 in the moving step ST12 according to the first embodiment, as shown in FIG. In this step, the end of the rotation orbit of the grinding wheel 16 is moved to a position where it partially overlaps the ring-shaped projection 112 .

In the cross section forming step ST13 according to the second embodiment, as shown in FIG. , an arc-shaped groove 130 is formed in an annular shape following the rotation orbit of the grinding wheel 16 . Thus, in the cross-section forming step ST13 according to the second embodiment, a cross-section 131 is formed on the side surface portion of the arc-shaped groove 130 crossing the area of the corner portion 113 .

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

Further, in the method for processing a workpiece according to the second embodiment, in the moving step ST12, the end of the rotational orbit of the grinding wheel 16 is moved to a position where it partially overlaps the ring-shaped convex portion 112, and in the cross-section forming step ST13, , the end portion of which is partially overlapped with the ring-shaped projection 112 to form an arc-shaped groove 130 that follows the rotation track of the grinding wheel 16 in an annular manner based on the arrangement of the plurality of grinding wheels 16 . Therefore, in the method for processing a 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 . For this reason, the method for processing a workpiece according to the second embodiment can easily direct the observation imaging device 20, and can form the cross section 131 that can be easily imaged and observed using the observation imaging device 20. During the work, the shape of the corner portion 113 can be confirmed and various judgments can be made.

It should be noted that the present invention is not limited to the above embodiments. That is, various modifications can be made without departing from the gist of the present invention.

REFERENCE SIGNS LIST 10 processing device 11 holding table 15 spindle 16 grinding wheel 17 grinding wheel 100 workpiece 102 back surface 111 circular concave portion 112 ring-shaped convex portion 113 corner portion 120, 130 groove 121, 131 cross section

Claims (1)

A method of machining a workpiece using a machining apparatus comprising a holding table that rotatably holds a workpiece and a grinding wheel that is rotatably held by a spindle and has a plurality of grinding wheels,
a grinding step of grinding the central portion of the back surface of the workpiece held on the holding table with the grinding wheel to form a circular concave portion and a ring-shaped convex portion surrounding the circular concave portion;
a moving step of relatively moving the grinding wheel and the holding table to a position where the rotation track of the grinding wheel passes through the ring-shaped protrusion after the grinding step;
After performing the moving step, the ring-shaped protrusion is ground by the grinding wheel to at least the height of the ring-shaped protrusion while the holding table is not rotated and the grinding wheel is rotated, and the ring is a cross-section forming step of forming a cross-section of the 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 of processing a workpiece, comprising:

Images