JP2002052447A - Notch grinding device for semiconductor wafer and notched groove chamfering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a notch grinding device and a notch grinding method allowing the formation of a highly precise V-slope in chamfering a notched groove of a semiconductor wafer. SOLUTION: The notch grinding device 11 comprises a grinding wheel 5 rotatably supported on a wheel spindle stock 40, a turn table 63 for rotatably holding the semiconductor wafer 1 around the center of curvature of a groove peak 3b of the notched groove 3, and an X-axis feeding mechanism 30 for moving the grinding wheel 5 straight in a plane parallel to the plate surface of the semiconductor wafer 1. The grinding wheel 5 being rotated is moved straight along the V-slope 3aL (3aR) of the notched groove 3 of the semiconductor wafer 1 in the plane parallel to the plate surface of the semiconductor wafer 1 and the semiconductor wafer 1 is rotated around the groove peak 3b of the notched groove 3, for providing the chamfering of the notched groove 3 of the semiconductor wafer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a notch grinding apparatus for grinding and chamfering a notch groove of a semiconductor wafer using a rotating grindstone, and a method for chamfering a notch groove.

[0002]

2. Description of the Related Art Conventionally, in a process of manufacturing a semiconductor device, a notch groove is formed by cutting a part of a peripheral edge of a wafer into a substantially V-shape or an arc in order to facilitate alignment of a crystal orientation of a semiconductor wafer. ing. The substantially V-shaped notch grooves are widely used because they can efficiently utilize a limited area of the wafer and have excellent positioning accuracy.

On the other hand, in a semiconductor device manufacturing process, the peripheral edge of the semiconductor wafer often contacts a part of an apparatus used in the manufacturing process. Such contact can sometimes generate dust and cracks. Therefore, the periphery or the notch groove of the semiconductor wafer is chamfered,
Today it is generalized.

[0004] Processing of the notch groove to an accurate size can shorten the time required for positioning in the next step of fine processing, so that high-precision grinding is required.

An example of such a notch grinding device is described in Japanese Patent No. 261829. This notch grinding device will be described with reference to FIG.

FIG. 23 is a conceptual diagram of a notch grinding device described in the above-mentioned patent publication. The notch grinding apparatus 100 includes a work holder 102 for rotatably holding a semiconductor wafer 101 and a Y-axis direction moving device 103 for moving the work holder 102 toward or away from a rotating grindstone 107. Further, a motor 108 for rotating a disc-shaped grindstone 107 for chamfering the notch groove 106, an X-axis direction moving device 104 for moving the grindstone 107 in the direction of its rotation axis, and a grindstone 107 with respect to the wafer 101 It comprises a Z-axis direction moving device 105 for moving in the vertical direction.

To perform chamfering of the wafer 101 by the notch grinding device 100, an X-axis direction moving device 104
And the Y-axis direction moving device 103 is driven to
7 is moved along the V slope of the notch groove 106. Further, by driving the Z-axis direction moving device 105,
The notch groove 106 can be ground from the upper surface direction to the lower surface direction of the wafer 101.

[0008]

According to the above notch grinding apparatus 100, the grinding wheel 107 is moved in the direction of the rotation axis of the grinding wheel by the X-axis direction moving device 104, and the wafer 101 is further moved by the Y-axis direction moving device 103. 107
By moving toward or away from the V-shaped notch groove 106, the feed movement in the X-axis direction and the Y-axis direction is combined.
The movement in the slope direction is realized.

However, it is complicated to control the amount of feed movement in the X-axis direction and the Y-axis direction along the V-slope of the V-shaped notch groove, and the movement in the V-slope direction is in the X-axis direction. Since the movement and the movement in the Y-axis direction are combined, there is a problem that it is difficult to accurately and linearly move along the V slope. Therefore, there is a demand to improve the straightness and surface roughness of the V slope. In particular, since the notch groove is used for positioning the straight portion of the V-slope in the subsequent process, high-precision notch groove processing is required.

Specifically, the V slope of the notch groove has a diameter of 3
This is a part where the positioning pin of about mm is in contact, and when the surface roughness of the chamfered portion of the notch groove is improved and the mirror finish is performed in the same manner as the chamfered portion on the outer periphery of the disk-shaped wafer, the surface roughness is reduced to 0.
It must be ground to about 1 μm. However, the X-axis direction moving device 104 and the Y-axis direction moving device 1 as described above
In the notch grinding apparatus 100 according to No. 03, the accuracy of the V slope may be insufficient.

The invention according to the present application has been made to solve the above-mentioned problems, and an object of the invention is to provide a notch grinding device capable of obtaining a highly accurate V-slope, and An object of the present invention is to provide a method for chamfering a notch groove.

[0012]

Means for Solving the Problems To achieve the above object, a first invention according to the present application is to provide a grindstone rotatably supported by a grindstone table on a plane parallel to a plate surface of a semiconductor wafer. In a notch grinding apparatus for a semiconductor wafer provided with a driving device for linearly moving the grindstone, the semiconductor wafer has a work support table that rotatably holds the center of curvature of a notch groove bottom circle center. Notch grinding device for semiconductor wafers.

Further, the second invention according to the present application is to move a rotating grindstone linearly along a V slope of a notch groove of the semiconductor wafer on a plane parallel to a plate surface of the semiconductor wafer. A method of chamfering a notch groove of a semiconductor wafer by rotating the semiconductor wafer around a center of curvature of a bottom circle of the notch groove.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention according to the present application will be described in detail with reference to FIGS. 1 to 6 and FIGS.

FIG. 9 shows a preprocessed semiconductor wafer 1 for chamfering a notch groove in the present embodiment.
FIG. Generally, a wafer 1 used for a semiconductor chip or the like is manufactured by cutting an ingot made of a hard and brittle material with a wire saw, and grinding the cut wafer 1 to a desired thickness with a grinding machine or a lapping machine.

The wafer 1 has a substantially disc-shaped appearance, and the outer periphery of the wafer 1 has a cylindrical outer peripheral portion 2 drawn around a center line running in the thickness direction through the center OW.
A V-shaped notch groove 3 is provided in a part of the outer peripheral portion 2.

In this embodiment, as shown in FIG. 21, the notch groove surface 3f of the edge of the notch groove 3 is substantially perpendicular to the plate surface 1a of the wafer 1 in the pre-processing. The presence or absence of finishing on the plate surface 1a of the preprocessed wafer 1 and the presence or absence of chamfering of the outer peripheral portion 2 may be any.

As shown in FIG. 10, the notch groove 3 has a V-shaped slope 3aL, which is cut in a V-shape and formed linearly.
3aR, a notch groove bottom circle 3b smoothly connecting a portion where the V inclined surfaces 3aL and 3aR on both sides intersect, and left and right mouth portions 3c for the notch groove 3 to smoothly transition to the outer peripheral portion 2. . Notch groove bottom circle 3b and mouth 3c
Is a circular arc in the present embodiment, but the notch groove bottom circle 3
b is a curve concave to the outside as viewed from the wafer 1;
c may be a curve that is convex to the outside as viewed from the wafer 1 and does not necessarily need to be arc-shaped.

The wafer 1 can take various sizes,
In this embodiment, the diameter is about 200 mm and the thickness is about 7 mm.
The notch groove 3 has a disk shape of about 00 to 900 μm, the width F between the left and right mouth portions 3c is 3 mm, and the depth H of the notch groove 3 is 1 to 1.5 mm. The notch groove bottom circle 3b has a radius R1 about the center of curvature 3g.
And its radius R1 needs to be 0.9 mm or more. The angle θ formed by the left and right V slopes 3aL and 3aR of the notch groove 3 is about 90 to 92 °. However, the present invention is not limited to the above size range,
Various values can be taken depending on the form of the wafer to be ground.

Next, the relationship between the grindstone 5 for grinding the wafer 1 and the notch groove 3 will be described with reference to FIG. FIG.
FIG. 3 is a view of the grindstone 5 and the grindstone rotating shaft 6 viewed from a direction parallel to the plate surface of the grindstone 5. The grindstone 5 has a disk shape, and a generatrix of the outer periphery of the grinding action portion forms an arc portion 5a. The grindstone 5 has a chest portion 5d having a constant width W in the direction of the grindstone rotation axis 6 smoothly connected to the arc portion 5a. Subsequently, a straight portion 5b is provided so as to gradually increase the width of the grindstone in the same direction, and smoothly extends from the straight portion 5b to the antinode 5c of the parallel plate surface. Here, the arc 5a
Is a grinding surface, and its radius of curvature R2 is smaller than radius R1 of the notch groove bottom circle 3b.

(Summary of the Invention) Next, FIGS.
The outline of the present invention will be described with reference to FIG.

According to the present invention, the notch groove 3 is formed by moving the grindstone 5 in the direction of the grindstone rotation shaft 6 and rotating the wafer 1 about the center of curvature 3g which draws the notch groove bottom circle 3b of the notch groove 3. Grinding.

As shown in FIG. 4, the wafer 1 held by the vacuum chuck 68 is arranged such that one V-sloped surface 3aL of the notch groove 3 is parallel to the grindstone rotating shaft 6 by the rotation of the turntable 63. , Turntable 63
To stop. The grindstone 5 moves in the X direction parallel to the grindstone rotation shaft 6, and is firstly fed and moved from right to left as viewed in FIG. At this time, since the V slope 3aL of the notch groove 3 is arranged parallel to the X-axis direction, the V slope 3a is moved by the feed movement of the grindstone 5 in the X-axis direction.
L is ground in a straight line.

Then, as shown in the enlarged view of the notch groove 3 at the lower right in FIG. 4, when the grinding stone 5 comes to the notch groove bottom circle 3b, FIG.
Then, the turntable 63 is rotated counterclockwise to grind the notch groove bottom circle 3b as shown in FIG. Turntable 6
Numeral 3 rotates around the center of curvature 3g of the notch groove bottom circle 3b. The rotation of the turntable 63 causes the notch groove bottom circle 3b to be ground into an arc shape. Assuming that the angle formed between the V slopes 3aL and 3aR of the notch groove 3 is θ °, the turntable 63 stops at a rotation of (180-θ) ° (see an enlarged view of the notch groove 3 at the lower right in FIG. 6).

The grindstone 5 is fed and moved along the X-axis as it is, and as shown in FIG. 6, the V-slope 3aR of the notch groove 3 is arranged parallel to the X-axis direction.
The V inclined surface 3aR is ground in a straight line by the feed movement in the X-axis direction.

By setting the center of rotation of the wafer 1 at the center of curvature 3g that describes the notch groove bottom circle 3b of the notch groove 3, the V of the notch groove 3 is simply moved by moving the grindstone 5 in the X-axis direction. Slope 3aL, 3aR and notch groove bottom circle 3
b can be chamfered.

(Regarding Configuration of Notch Grinding Apparatus)
FIG. 1 shows a specific configuration of the notch grinding device of the present invention.
This will be described with reference to FIG. FIG. 1 is a side view of the notch grinding device 11, and FIG. 2 is a plan view of the notch grinding device 11.

As shown in FIG. 1, the bed 12 is provided with an XY table including a Y-axis feed mechanism 20 and an X-axis feed mechanism 30.
Is provided.

The Y-axis feed mechanism 20 includes a Y-axis slide rail 21, a Y-axis guide 22 fitted to the Y-axis slide rail 21, a saddle 23, a Y-axis control motor 24, a Y-axis feed screw 25, and a nut 26. It is composed of The Y-axis slide rail 21 is provided on the upper surface of the bed 12,
A saddle 23 is mounted on the shaft slide rail 21. A Y-axis guide 22 is fixed to the bottom surface of the saddle 23, and the Y-axis guide 22 is movably fitted along the Y-axis slide rail 21.

As shown in FIG. 2, the Y-axis control motor 24
Are fixed to the bed 12 by brackets 28. A Y-axis feed screw 25 is provided on the rotation axis of the Y-axis control motor 24, and the Y-axis control motor 24 rotates the Y-axis feed screw 25. In saddle 23,
A nut 26 (see FIG. 1) in which the Y-axis feed screw 25 is screwed is fixed, and the nut 26 is fed in the Y-axis direction by rotation of the Y-axis feed screw 25, so that the saddle 23 is Move in the Y-axis direction. At this time, saddle 23
Is moved along the Y-axis direction by being guided along the Y-axis slide rail 21 by the Y-axis guide 22 as shown in FIG.

An X-axis feed mechanism 30 is further provided on the saddle 23 as shown in FIG. The X-axis feed mechanism 30 includes an X-axis slide rail 31, an X-axis guide 32 fitted to the X-axis slide rail 31,
Slide table 33 for supporting the X-axis control motor 3
4. It comprises an X-axis feed screw 35 and a nut (not shown) screwed into the X-axis feed screw 35. The X-axis slide rail 31 is provided on the upper surface of the saddle 23, and a slide table 33 is mounted on the X-axis slide rail 31. An X-axis guide 32 is fixed to the bottom surface of the slide table 33, and the X-axis guide 32 is fitted so as to be movable along the X-axis slide rail 31.

The X-axis control motor 34 is fixed to the saddle 23 by a bracket 38. An X-axis feed screw 35 is provided on the rotation axis of the X-axis control motor 34, and the X-axis feed screw 3
5 rotates. A nut (not shown) screwed into the X-axis feed screw 35 is fixed to the slide table 33, and the nut is fed in the X-axis direction by rotation of the X-axis feed screw 35. Slide table 33 is X
Move in the axial direction. At this time, the slide table 33
Is guided along the X-axis slide rail 31 by the X-axis guide 32 and moves in the X-axis direction.

In this embodiment, as shown in FIG. 2, the X-axis slide rail 31 and the Y-axis slide rail 21 are arranged so as to be perpendicular to each other. Good if not.

As shown in FIG. 1, the grindstone table 40 comprises a grindstone main body 40a, a grindstone rotation drive motor 10, a grindstone rotation shaft 6, and a grindstone 5 for grinding. Wheel head body 40
a is fixed to the slide table 33. The grindstone rotation drive motor 10 is provided in the grindstone head main body 40a, and the grindstone 5 for grinding is mounted on the grindstone rotation axis 6 of the grindstone rotation drive motor 10. The grindstone rotation drive motor 10 is provided so that the grindstone rotation shaft 6 is parallel to the XY plane formed by the X-axis direction and the Y-axis direction and parallel to the X-axis direction.

When the grinding wheel 5 has a disk shape and the cross section of the grinding wheel 5 is formed by a plane including the grinding wheel rotation shaft 6, the grinding surface of the grinding stone 5 has a radius of curvature smaller than at least the radius of curvature R1 of the notch groove bottom circle 3b. It has an arc shape having R2. The width W of the grindstone near the outer periphery of the grindstone 5 is the notch groove bottom circle 3b.
Is smaller than twice the radius R1 of the curve so that the grinding wheel side surface does not interfere with the notch groove 3 when the bottom of the notch groove 3 is ground.

As shown in FIG. 1, the bed 12 is provided with a turntable 63 having a vacuum chuck 68 for holding the wafer 1 to be ground.
Is provided on an elevating mechanism 50 for moving up and down in the Z-axis direction. The lifting mechanism 50 includes a lifting table 53, a Z-axis slide rail 51 that guides the lifting table 53, and a Z-axis guide 52 that is fitted to the Z-axis slide rail 51.
Further, it comprises a Z-axis control motor 54, a Z-axis feed screw 55, and a nut 56. The Z-axis feed screw 55 is connected to the Z-axis control motor 5
4 is provided on the rotation axis of the Z-axis control motor 54.
Rotates the Z-axis feed screw 55. The Z-axis control motor 54 is fixed to the bed 12 by a bracket 58.

The lifting table 53 has a Z-axis feed screw 55
The nut 56 screwed into the nut is fixed.
As the shaft feed screw 55 rotates, the nut 56 moves upward or downward, and the elevating table 53 performs an elevating operation. The elevating table 53 is provided with a Z-axis slide rail 51 extending vertically, and a Z-axis guide 52 fitted movably along the Z-axis slide rail 51.
Are fixed to the bed 12. When the lifting table 53 moves up and down, the Z-axis slide rail 51 is guided by the Z-axis guide 52 and slides.
Numeral 3 performs an elevating operation along the Z-axis slide rail 51.

FIG. 3 is a view of the turntable 63 as viewed from above, and shows a state where the wafer 1 is not mounted on the vacuum chuck 68. As shown in FIG. 3, the turntable 63 is provided on the elevating table 53,
The movement in the Z-axis direction is performed with the lifting operation of the lifting table 53. A vacuum chuck 68 is provided on the upper surface of the turntable 63.
Is provided. The vacuum chuck 68 has a circular shape smaller than that of the wafer 1, and its center does not coincide with the rotation center of the turntable 63, and is mounted in a shifted state.
A plurality of suction holes 68a are formed on the upper surface of the vacuum chuck 68, and the wafer 1 is vacuum-sucked and fixed on the vacuum chuck 68 by sucking air from the suction holes 68a.

As shown in FIG. 1, the turntable 63 has a rotation shaft 63a in a direction perpendicular to the table surface, and the rotation shaft 63a is connected to a rotation shaft 64a of a table rotation control motor 64 provided on the lifting table 53. Connected. The table rotation control motor 64 is provided so that the rotation shaft 64a is parallel to the Z-axis direction. The turntable 63 is controlled by controlling the rotation of the table rotation control motor 64.
To control the rotation of

The wafer 1 is placed on the vacuum chuck 68 of the turntable 63 with the plate surface 1a having the X-axis and the Y-axis.
The wafer 1 is arranged so as to be substantially parallel to the XY plane formed by the axes, and the Z axis is arranged in a direction substantially orthogonal to the plate surface 1 a of the wafer 1.

In the above description, the Y-axis control motor 24, the X-axis control motor 34, the Z-axis control motor 54 and the table rotation control motor 64 are servo motors, respectively.
It is controlled by the NC control device 8.

(Operation of Notch Grinding Apparatus) Next, the operation of chamfering the notch groove 3 by the notch grinding apparatus 11 will be described.

First, the wafer 1 on which the plate surface grinding has been completed is placed on the vacuum chuck 68 of the turntable 63, and alignment is performed so that one V slope 3aL of the notch groove 3 is parallel to the X-axis direction. . This positioning is performed by using three positioning pins 4a and 4b as shown in FIG. When the positioning pins 4a and 4b are connected by a straight line, the remaining two pins 4b are arranged at the corners of the base of the triangle with the pin 4a fitted into the notch groove 3 as the apex.
The positioning pins 4a and 4b are cylindrical, and the pins 4a are in contact with the wafer 1 at straight portions of the V slopes 3aL and 3aR.

First, the wafer 1 placed on the vacuum chuck 68 has its outer peripheral portion 2 supported by two pins 4b. The operation of mounting the wafer 1 on the vacuum chuck 68 is performed by a transfer device or the like. Then, with the pins 4b abutting on the outer peripheral portion 2 of the wafer 1, the positioning pins 4a are inserted from the outer periphery toward the center OW of the wafer 1 along the radial direction, and the pins 4a and the V slope 3a are inserted.
L, 3aR is brought into contact.

The position of the notch groove bottom circle 3b is detected from the position of the pin 4a, and the notch groove bottom circle 3b is moved such that the position of the notch groove bottom circle 3b coincides with the center of the rotary shaft 63a of the turntable 63. After that, the suction holes 6 provided in the vacuum chuck 68
The wafer 1 is vacuum-sucked on the vacuum chuck 68 by vacuum-suctioning from the wafer 8a.

When the wafer 1 is sucked by the vacuum chuck 68 and the wafer 1 is held on the turntable 63, the positioning pins 4a are retracted. Then, the turntable 63 is rotated, and one V slope 3a of the notch groove 3 is turned.
Positioning is performed so that L is parallel to the X-axis direction, and the turntable 63 is stopped. When the position of the notch groove bottom circle 3b is detected without rotating the turntable 63 as described above, the wafer 1 is set so that one V slope 3aL of the notch groove 3 is parallel to the X-axis direction from the beginning.
May be held on the turntable 63.

When the positioning is completed, the grindstone rotation drive motor 10 is started to rotate the grindstone 5 fixed to the grindstone rotation shaft 6. During the automatic operation of the notch grinding device 11, the grindstone 5 may be continuously rotated without stopping the grindstone rotation drive motor 10. The notch grinding device 11 according to the present embodiment first performs rough grinding using a roughing grindstone, and then performs finish grinding using a finishing grindstone.

Next, the control of the grindstone 5 and the turntable 63 will be described in detail with reference to FIGS.

As shown in FIG. 4, the wafer 1 held by the vacuum chuck 68 is positioned by the above-described alignment.
One V-slope 3 aL of the notch groove 3 is arranged so as to be parallel to the grinding wheel rotation axis 6.

The grindstone 5 is moved by the Y-axis feed mechanism 20 to a position just before the grindstone 5 comes into contact with the wafer 1.
And move it toward. At this time, the grindstone 5 is disposed on the right side of the opening 3c on the right side of the notch groove 3. Then, the grindstone 5 is fed and moved in an arc shape by the X-axis feed mechanism 30 and the Y-axis feed mechanism 20 so as to match the shape of the mouth 3c of the notch groove 3, and the mouth 3c is ground.

Thereafter, the drive of the Y-axis feed mechanism 20 is stopped to stop the feed in the Y-axis direction, and the grinding wheel 5 is fed in the direction of the arrow in FIG. 4 by the rotation of the X-axis control motor 34 and the X-axis feed screw 35. Move. The grindstone 5 moves along the V slope 3aL of the notch groove 3 while rotating about the grindstone rotation shaft 6,
The V slope 3aL is chamfered.

At this time, the V slope 3aL of the notch groove 3 is X
The X-axis feed mechanism 30 is arranged in parallel with the axial direction.
, The V inclined surface 3aL is ground straight and with high precision.

Then, as shown in the enlarged view of the notch groove 3 at the lower right in FIG. 4, when the grinding stone 5 comes to the notch groove bottom circle 3b of the notch groove 3, the turntable 63 is rotated as shown in FIG. The notch groove bottom circle 3b is ground. Specifically, when the straight portion of the V slope 3aL ends and the center line bisecting the grindstone width W of the grindstone 5 comes to a position approaching the arc portion of the notch groove bottom circle 3b, the table rotation control is performed. The rotation of the motor 64 causes the turntable 63 to rotate in the direction of the arrow. The turntable 63 rotates about a center of curvature 3g that draws an arc of the notch groove bottom circle 3b.
By the rotation of 3, the notch groove bottom circle 3b is ground in an arc shape.

When the angle between the V slopes 3aL and 3aR of the notch groove 3 is θ °, the turntable 63 becomes (180−
The rotation is controlled by the table rotation control motor 64 so as to stop when the rotation is θ) °.

Then, as shown in FIG. 6, the grinding wheel 5 is fed and moved along the X-axis by the X-axis feed mechanism 30. This time, the V slope 3aR of the notch groove 3 is parallel to the X-axis direction. Since they are arranged, the V inclined surface 3aR is ground in a straight line by the feed movement of the grindstone 5 in the X-axis direction.

After grinding the straight portion of the V slope 3aR, the Y-axis feed mechanism 20 is driven again, and the X-axis feed mechanism 3
The whetstone 5 is moved in an arc shape so as to conform to the shape of the opening 3c on the left side of the notch groove 3 by the 0 and Y-axis feed mechanism 20, and the opening 3c is ground.

After the grinding of the mouth 3c is completed, the grindstone 5 is once separated from the wafer 1 by the Y-axis feed mechanism 30, and the wafer 1 is raised by the lifting mechanism 50. And whetstone 5
Is again brought close to the wafer 1, and the notch groove 3 is ground on another plane in the same manner as described above.

As described above, by setting the center of rotation of the wafer 1 to the center of curvature 3g of the notch groove bottom circle 3b of the notch groove 3, the X-axis feed mechanism 30 feeds and moves the grindstone 5 in the X-axis direction. V slope 3aL, 3aR of groove 3
And the notch groove bottom circle 3b can be chamfered. For this reason, it is possible to machine the linear portions of the V slopes 3aL and 3aR, which require particularly high precision, with high precision compared to the case where the feed movement in the X-axis direction and the feed movement in the Y-axis direction are combined to grind the V slope. it can.

The center of rotation of the turntable 63 is
The V slopes 3aL and 3aR need only be on the bisector of the angle θ, and need not necessarily coincide with the curvature center 3g of the notch groove bottom circle 3b. That is, the V slopes 3aL, 3aR
Is located on the bisector of the angle θ, and the notch groove bottom circle 3
If it is a point near the center of curvature b, even if it is rotated about that point, it can be processed with high accuracy. Therefore,
In the present application, the center of curvature of the notch groove bottom circle 3b includes a point located on the bisector of the angle θ formed by the V slopes 3aL and 3aR and near the center of curvature 3g of the notch groove bottom circle 3b.

If the notch groove bottom circle 3b of the notch groove 3 is arc-shaped and its radius of curvature R1 is large, the chuck 6
When the wafer 1 is attracted to the nozzle 8, the notch groove bottom circle 3 b and the rotation center of the turntable 63 are spaced apart from each other,
The position of the grindstone 5 may be shifted accordingly.

If the notch groove bottom circle 3b of the notch groove 3 has a curved shape other than an arc, the notch groove bottom circle 3b
b can be ground by simultaneous two-axis control by the X-axis feed mechanism 30 and the Y-axis feed mechanism 20. Further, the notch groove bottom circle 3b is arc-shaped and the size of the radius R1 is equal to the curvature center 3g.
Can be ground by the simultaneous control of two axes by the X-axis feed mechanism 30 and the Y-axis feed mechanism 20.

FIG. 13 is a cross-sectional view showing a longitudinal section of the notch groove 3 of the wafer 1 to show the positional relationship between the wafer 1 and the grindstone 5 in the Y-axis direction and the Z-axis direction. As shown in FIG. 13, assuming that the rotation axis center O of the grindstone 5 is O1 to O5,
The grindstone 5 relatively moves so that each center O1 to O5 draws a tool path on a plurality of planes parallel to the plate surface 1a of the wafer 1. In the notch grinding device 11 shown in FIG.
The X-axis feed mechanism 30 and the Y-axis feed mechanism 20 are controlled, and the wafer 1 is ground by rotating the notch groove 3 around the notch groove bottom circle 3b.

FIG. 14 shows the relative tool path (relative tool path) drawn by the grindstone 5 when the wafer 1 is fixed. The relative tool path is represented by reference numerals TP1 to TP5 shown in FIG. 14 when represented by a point T on the side closer to the wafer 1 at the center of the arc of the tip arc portion 5a of the grindstone 5 as shown in FIG. This relative tool path is also the same at the center of the grinding wheel 5 (the intersection of the plane passing through the point T and perpendicular to the grinding wheel rotation center line and the grinding wheel rotation center line). Therefore, in the following description, description will be made using the relative tool path at the center of the grindstone 5.

In any of the relative tool paths TP1 to TP5, the V-slope located on the opposite side to the symmetry center SL through the left opening 3c, the V-slope 3aL, and the notch groove bottom circle 3b shown in FIG. 3aR and the right mouth 3c can be chamfered continuously. Further, on both sides of the relative tool path that can be chamfered, a relative tool path portion TPA for performing air cutting is provided.

As shown in FIG. 14, at the ends O1 'to O5' of the air cut tool path portion TPA (which are also the ends of the relative tool path TP), as shown by a two-dot chain line in FIG. 5 and the wafer 1 are apart. The ends O1 'to O5' of the relative tool path portion TPA correspond to the grinding wheel centers O1 to O5, respectively.

Referring to FIGS. 10 and 14, a specific control method of the X-axis feed mechanism 30, the Y-axis feed mechanism 20, and the turntable 63 will be described.

First, the grindstone rotation drive motor 10 is rotated, and the grindstone 5 attached to the grindstone rotation shaft 6 is rotated. In the present embodiment, the chamfer of the notch groove 3 is mirror-finished by roughing and finishing.
Initially, grinding is performed using a roughing grindstone. In addition, it is possible to perform from roughing to finishing by dividing the cutting speed into a plurality of stages using only one grindstone without using two types of grindstones for roughing and finishing. .

Then, the center of the grinding wheel 5 for rough machining is
The Y-axis feed mechanism 20 is controlled so as to be arranged at 1 '. When the center of the grindstone is at O1 ', the grinding surface of the grindstone 5 is not yet in contact with the wafer 1.

Next, the Y-axis control motor 24 of the Y-axis feed mechanism 20 is operated to move the grinding surface of the grindstone 5 to a position where it contacts the left opening 3c of the wafer 1. From this state, the wafer starts to be ground by the grindstone 5.

The X-axis feed mechanism 30 and the Y-axis feed mechanism 20 are controlled to perform grinding so that the opening 3 c of the notch groove 3 smoothly extends to the outer peripheral portion 2 of the wafer 1. This mouth 3
c is a portion where the outer peripheral portion 2 and the V slope 3a of the notch groove 3 are connected to each other, and is a place where dust is likely to be generated due to contact with the manufacturing apparatus in the subsequent semiconductor production process. It must be formed as smoothly as possible.

When the chamfering of the mouth 3c is completed,
This leads to grinding of the slope 3aL. Main notch grinding device 11
Can move the grindstone 5 parallel to the V slope 3aL only by the X-axis feed mechanism 30 without operating the Y-axis feed mechanism 20.

When grinding of the straight portion of the V slope 3aL is completed, grinding of the notch groove bottom circle 3b is performed.
Since the notch groove bottom circle 3b is an arc having a radius of curvature of R1, the rotation of the table rotation control motor 64 causes
The turntable 63 is rotated, and the whetstone 5 is moved so as to draw an arc having a radius R1.

When the grinding of the notch groove bottom circle 3b is completed, grinding of the straight portion of the V slope 3aR is performed. V slope 3
Grinding of aR is also performed by the feed of the X-axis feed mechanism 30.

Thereafter, by controlling the X-axis feed mechanism 30 and the Y-axis feed mechanism 20, the mouth 3c, which is a connection portion with the outer peripheral portion 2, is smoothly ground. The grindstone 5 is moved to the end portion O1 'of the wafer 1 to separate the grindstone 5 from the wafer 1.

By performing the same control for TP2 to TP5 in the same manner, the wafer 1 can be chamfered. At this time, in order to shorten the grinding operation time as much as possible, as shown in FIG. 14, TP2 grinds from the opposite direction to TP1. Similarly, TP3 grinds from a direction opposite to TP2, TP4 grinds from a direction opposite to TP3, and TP5 grinds from a direction opposite to TP4. By performing such control, the relative tool path is shortened, and the working time is shortened.

Next, the positional relationship between the case where the grinding wheel 5 is performing the grinding operation and the case where the grinding wheel 5 is away from the wafer 1 will be described with reference to FIG. FIG. 16 is a view showing a vertical cross section of the notch groove 3 of the wafer 1. When the center of the grindstone is at O 1, the case where the grinding operation of the wafer 1 is being performed is shown.
When it is at 1 ', it indicates a state where it is separated from the wafer 1. The case where the X-axis feed mechanism 30 and the turntable 63 are controlled to feed the grindstone 5 relatively along the tool path TP1 as shown by the arrow in FIG. 14 will be described.

First, the air cut tool path T on the left side
When the grinding surface of the grindstone 5 passes through the PA and comes into contact with the wafer 1, as shown in FIG. 16, the stock S1 of the portion provided with the sectional line along the edge of the notch groove 3 is removed, and the chamfer C1 is formed.
Is formed. And the right air cut tool path T
When the center of the grindstone reaches the right end O1 'shown in FIG. 14 and enters the PA, the grindstone 5 is separated from the wafer 1 as shown by a two-dot chain line in FIG.

Here, the Z-axis control motor 54 of the lifting mechanism 50
Is controlled to move the slide table 33 backward in a direction away from the wafer 1 by controlling the Y-axis feed mechanism 20. As shown in FIG. 16, the amount of rise of the wafer 1 is set at the center O1, O2 or O1 ', O1 of the grindstone.
The 2 ′ Z-direction difference ΔZ1, and the retreat amount of the slide table 33 is the Y-direction difference ΔY1 between the relative tool paths TP1 and TP2 in FIG.

Next, the X-axis feed mechanism 30 and the turntable 63 are controlled in the opposite direction to the case of TP1 to move the grindstone 5 relatively left along the relative tool path TP2 as shown by the arrow in FIG. To the notch groove 3 as shown in FIG.
The stock S2 at the portion where the cross-section line is provided along the edge of is removed, and a chamfer C2 is formed. When the center of the grindstone reaches the left end O2 'in FIG. 14, the grindstone 5 is located away from the wafer 1 as shown by the two-dot chain line in FIG.

The Z-axis control motor 54 of the elevating mechanism 50 is controlled to raise the wafer 1 and the Y-axis feed mechanism 20
To move the slide table 33 backward. As shown in FIG. 17, the amount of rise of the wafer 1 is set at the center of the grinding wheel O2, O3.
Alternatively, the Z direction difference ΔZ2 between O2 ′ and O3 ′, and the retreat amount of the slide table 33 is shown in a plan view in FIG.
4 is the difference ΔY2 in the Y direction between the relative tool paths TP2 and TP3.

When the X-axis feed mechanism 30 and the turntable 63 are controlled to feed the grindstone 5 relatively rightward along the relative tool path TP3 as shown by an arrow in FIG. As shown in FIG. 18, the stock S3 at the section where the cross section line is formed is removed, and a chamfer C3 is formed.
When the center of the grindstone reaches the end O3 'on the right side in FIG. 14, the grindstone 5 is located away from the wafer 1 as shown by the two-dot chain line in FIG.

The Z-axis control motor 5 of the lifting mechanism 50
4 is controlled to raise the wafer 1 and the Y-axis feed mechanism 20 is controlled to move the slide table 33 forward. As shown in FIG.
Grinding stone center O3, O4 or O3 ', O4' Z direction difference ΔZ
3 and the amount of advance of the slide table 33 is represented by the relative tool paths TP2 and TP3 in FIG.
Is the difference in the Y direction の Y3.

Next, the X-axis feed mechanism 30 and the turntable 63 are controlled to move along the relative tool path TP4 as shown in FIG.
When the sheet is fed relatively to the left as indicated by an arrow 4, the stock S <b> 4 having a section line along the edge of the notch groove 3 as shown in FIG. 19 is removed, and a chamfer C <b> 4 is formed. When the center of the grindstone reaches the left end O4 'in FIG. 14, the grindstone 5 is positioned away from the wafer 1 as shown by the two-dot chain line in FIG.

Here, the Y-axis feed mechanism 20 and the elevating mechanism 50
To raise the wafer 1 and advance the slide table 33. As shown in FIG. 19, the amount of rise of the wafer 1 is Z of the grinding wheel center O4, O5 or O4 ', O5'.
The direction difference ΔZ4, and the amount of advance of the slide table 33 corresponds to the relative tool path T in FIG. 14 shown in a plan view.
The difference in the Y direction between P4 and TP5 is ΔY4.

X-axis feed mechanism 30 and turntable 63
Is controlled and is sent to the right along the relative tool path TP5 shown in FIG. 14 as indicated by the arrow, and along the edge of the notch groove 3, a portion having a sectional line as shown in FIG. The stock S5 is removed, and a chamfer C5 is formed. In FIG. 14, when the center of the grindstone reaches the right end O5 ', the grindstone 5
Is located away from the wafer 1 as shown by the two-dot chain line in FIG. Then, the slide table 33 is moved backward by controlling the Y-axis feed mechanism 20.

When the chamfering with the roughing grindstone is completed as described above, the chamfering is similarly performed with the finishing grindstone. In addition, chamfering with a grinding wheel for finishing
Although the chamfering is performed finely by increasing the number of TPs, the operation is the same as that of the chamfering using the roughing grindstone, and thus the description thereof is omitted.

When the finishing is completed, the X-axis feed mechanism 3
The wafer 1 is raised by controlling the 0 and Y axis feed mechanism 20 and the elevating mechanism 50, and the slide table 33 is moved backward. At this time, the wafer 1 rises to a position where the wafer 1 can be replaced.

In the method of chamfering the notch groove 3 by grinding in the above-described steps, the chamfer is polygonal, and in this example, the chamfer is five-chamfered (the chamfered portion has six corners). The upper and lower surfaces of the wafer 1 are chamfered in a substantially symmetric shape. According to a trial calculation, the distance between a curve that is in contact with each side of each of the chamfers C1 to C5 cut by a slope perpendicular to the edge of the notch groove 3 and each corner between the chamfers C1 to C5 is 12 μm at maximum. Further, when the chamfered shape is 9 (10 corners of the chamfered portion), the distance between the curve contacting the sides of the chamfers C1 to C9 and the respective corners between the chamfers C1 to C9 is a maximum of 2 μm. Therefore, the time for rounding the corners by chamfering by buffing or the like performed as a post-process of the notch groove 3 is about 1 minute in this example, and the post-process time is extremely reduced as compared with the conventional case.

In this chamfering, the cross-sectional shape of the chamfer becomes smoother as the polygon becomes more polygonal, such as 7 chamfered shapes (8 corners of the chamfered portion) than 5 chamfered shapes, and 9 chamfered shapes than 7 chamfered shapes. It becomes almost arc-shaped. In the chamfering of the notch groove 3 of the wafer 1, it is desirable that the shape be at least five or more. Further, the chamfered shape does not necessarily have to be an odd-numbered chamfer, and may be a six-chamfered shape (seven chamfered corners) or an eight-chamfered shape (9 chamfered corners).

Further, in this embodiment, since the mirror grinding condition can be obtained by using the optimal grinding stone, the Rm
ax A surface roughness of about 0.1 μm can be obtained. This eliminates the occurrence of chipping and cracking. Further, since a large-diameter grindstone can be used, it is relatively easy to maintain the shape of the grindstone grinding surface even when a soft grindstone required for mirror finishing is used.

The relative tool path described above is an example, and for example, the order of chamfering C1 → C5 → C4 → C2 → C3 may be adopted. Although the cut is shown once, the cut may be made in a plurality of times. Although the relative tool paths TP1 and TP5 and TP2 and TP4 are the same, the relative tool paths TP1 and TP5, and TP2 and TP4 may be different.

Further, the present invention is characterized in that the wafer 1 is rotated about the center of curvature 3g of the notch groove bottom circle 3b, and the control in the Z-axis direction and the Y-axis direction is performed as shown in FIG. It can also be applied to a notch grinding device that performs chamfering by causing the grindstone 5 to contour according to the cross-sectional shape of the chamfered portion.

In the present embodiment, the plate surface of the wafer 1 and the plate surface of the grindstone 5 intersect at a difficult angle, but the intersection angle is not limited to a right angle. By making the crossing angle slightly inclined than a right angle, the contact surface between the grinding action surface of the grindstone 5 and the wafer 1 is increased, the grinding efficiency is increased, and the streak formed in the notch groove 3 becomes an inclined line. Therefore, it is possible to prevent the notch groove 3 from being cracked or cracked from the groove bottom 3b.

FIG. 21 is a perspective view of the wafer 1 before the chamfering, and FIG. 22 is a perspective view of the notch groove of the wafer after the chamfering. In FIG. 21, the notch groove surface 3f is substantially perpendicular to the plate surface 1a and has a substantially right-angled corner, whereas in the wafer 1 shown in FIG. 22, the notch groove 3 is chamfered. The corners form a gentle obtuse angle. Therefore, chipping of the wafer 1 due to contact can be prevented, and generation of dust can be prevented.

In the present embodiment, the slide table 33 moves in the X-axis direction and the Y-axis direction. However, the turntable 63 may move instead of the slide table 33. Further, instead of the turntable 63, the slide table 33 may be moved up and down in the Z-axis direction. That is, any configuration is possible as long as the grindstone 5 and the wafer 1 can move relative to each other in the X-axis direction, the Y-axis direction, and the Z-axis direction. Further, in the present embodiment, the direction of the Z axis is perpendicular to the XY plane formed by the X axis and the Y axis, but it is not necessarily required to be perpendicular, and the direction intersecting with the XY plane (the XY plane and the Any direction that is not parallel is acceptable.

As described above, according to the present invention, in the grinding of the notch groove 3, the V-slope 3
Since aL and 3aR are ground only by the feed by the X-axis feed mechanism 30, they can be ground accurately and straight.

When grinding a plurality of types of wafers 1 having different angles θ of the notch grooves 3, the V slopes 3aL, 3a
The rotation angle of the turntable 63 may be controlled to (180-θ) ° in accordance with the angle θ of aR, and the feed in the X-axis direction and the Y-axis direction are combined to grind the V slopes 3aL and 3aR. Control according to each wafer is easier than a grinding device.

Next, a second embodiment of the present invention will be described with reference to FIGS.

This embodiment is different from the first embodiment in that a disk-shaped grinding wheel 5 is used instead of a grinding wheel 5 '.
Therefore, description of the same parts as in the first embodiment will be omitted.

As shown in FIG. 7, the forming grindstone 5 'has a concave bus bar 5 corresponding to the convex chamfer bus bar of the notch groove 3.
This is a rotary grindstone having a ′, and has a radius of curvature r (diameter d) smaller than the radius of curvature R1 of the notch groove bottom circle 3b. The formed grindstone 5 ′ rotates about a grindstone rotating shaft 6 ′ on a plane parallel to the plate surface 1 a of the wafer 1 to chamfer the notch groove 3. The notch grinding device according to the present embodiment is configured such that a grinding wheel rotating shaft 6 ′ is attached to a plate surface 1 of the wafer 1 in a grinding wheel table 40 of the notch grinding device 11 shown in FIGS.
It is arranged in the Z-axis direction so as to be orthogonal to a.

In the case of chamfering, as in the first embodiment, the V-slope 3aL of the notch groove 3 of the wafer 1 is arranged so as to be parallel to the X-axis, and the grinding wheel 5 'is fed in the X-axis direction. The mechanism 30 feeds and moves in a straight line along the V slope 3aL. Then, when the formed grindstone 5 'comes to the notch groove bottom circle 3b, the wafer 1 is rotated around the center of curvature 3g of the notch groove bottom circle 3b by the turntable 63 to grind the notch groove bottom circle 3b. When the V slope 3aR of the notch groove 3 becomes parallel to the X axis, the rotation of the turntable 63 is stopped, and the V slope 3aR is ground straight by the feed of the X axis feed mechanism 30 as it is.

FIG. 8 shows the relative tool path 13 of the forming grindstone 5 'when the rotation of the wafer 1 is stopped. In the present embodiment, the notch groove 3 can be chamfered according to the shape of the bus bar 5a 'only by feeding once, without reciprocating the forming grindstone 5' on a plurality of planes.

As described above, according to the invention of the present application, the grindstone 5 (5 ') rotatably supported by the grindstone table 40 and the semiconductor wafer 1 are centered on the center of curvature of the notch groove bottom circle 3b of the notch groove 3. A notch grinding device 11 having a turntable 63 for rotatably holding the wafer and an X-axis feed mechanism 30 for linearly moving the grindstone 5 (5 ') on a plane parallel to the plate surface 1a of the semiconductor wafer 1. is there.

In another invention according to the present invention, the rotating grindstone 5 (5 ') is provided on a plane parallel to the plate surface 1a of the semiconductor wafer 1 on the V slope 3aL of the notch groove 3 of the semiconductor wafer 1. (Or 3aR) to move the semiconductor wafer 1 linearly along the notch groove bottom circle 3 of the notch groove 3.
In this method, the notch groove 3 of the semiconductor wafer 1 is chamfered by rotating the center of curvature b around the center of curvature.

[0105]

As described above, according to the present invention, the V-slope, which is the linear portion requiring the highest precision, is ground by the feed of one feed mechanism in the notch groove grinding. Can be ground.

Further, when grinding a plurality of types of wafers having different angles formed by the notch grooves, it is only necessary to control the rotation angle of the turntable in accordance with the angle of the V-slope. Easy.

[Brief description of the drawings]

FIG. 1 is a side view of a notch grinding device according to the present invention.

FIG. 2 is a plan view of the notch grinding device of the present invention as viewed from above.

FIG. 3 is a plan view of the turntable of the present invention as viewed from above.

FIG. 4 is a plan view showing a notch groove grinding step according to the present invention.

FIG. 5 is a plan view showing a step of grinding a notch groove according to the present invention.

FIG. 6 is a plan view showing a notch groove grinding step according to the present invention.

FIG. 7 is a side view showing a relationship between a forming whetstone and a wafer according to another embodiment of the present invention.

FIG. 8 is a plan view showing a relative tool path of a forming wheel according to another embodiment of the present invention.

FIG. 9 is a plan view of a wafer before chamfering is performed.

FIG. 10 is a plan view showing a shape of a notch groove of a wafer before chamfering is performed.

FIG. 11 is a plan view showing a relationship between a wafer and a grindstone.

FIG. 12 is a plan view showing how a wafer is positioned by positioning pins.

FIG. 13 is a cross-sectional view showing a chamfered shape of a notch groove of a wafer, which is cut by a slope with respect to an edge of the notch groove.

FIG. 14 is a plan view showing a relative tool path of a grindstone.

FIG. 15 is a vertical sectional view of a tool moving path.

FIG. 16 is a vertical sectional view showing a chamfering step.

FIG. 17 is a vertical sectional view showing a chamfering step.

FIG. 18 is a vertical sectional view showing a chamfering step.

FIG. 19 is a vertical sectional view showing a chamfering step.

FIG. 20 is a vertical sectional view showing a chamfering step.

FIG. 21 is a perspective view of a notch groove before chamfering is performed.

FIG. 22 is a perspective view of a notch groove after chamfering.

FIG. 23 is a conceptual diagram showing a conventional notch groove grinding device.

FIG. 24 is a longitudinal sectional view showing a state in which a notch groove is chamfered by contouring a grindstone.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wafer 1a ... Plate surface 2 ... Outer peripheral part 3 ... Notch groove 3aL, 3aR ... V slope 3b ... Notch groove bottom circle 3c ... Mouth 3f ... Notch groove surface 3g ... Center of curvature 4a, 4b ... Pin 5 ... Grinding stone 5a ... Arc part 5b ... Linear part 5c ... Abdomen 5 '... Form wheel 5a' ... Busbar 6 ... Wheel rotation axis 6 '... Wheel rotation axis 8 ... CNC control device 10 ... Wheel rotation drive motor 11 ... Notch grinding device 12 ... Bed 13 Tool path 20 Y-axis feed mechanism 21 Y-axis slide rail 22 Y-axis guide 23 Saddle 24 Y-axis control motor 25 Y-axis feed screw 26 Nut 28 Bracket 30 X-axis feed mechanism 31 X-axis slide rail 32 ... X-axis guide 33 ... Slide table 34 ... X-axis control motor 35 ... X-axis feed screw 38 ... Bracket 40 ... Whetstone base 40a ... Whetstone base body 50 ... Elevator Structure 51 ... Z-axis slide rail 52 ... Z-axis guide 53 ... Elevating table 54 ... Z-axis control motor 55 ... Z-axis feed screw 56 ... Nut 58 ... Bracket 63 ... Turn table 63a ... Rotating axis 64 ... Table rotation control motor 64a ... Rotating shaft 68 ... Chuck 68a ... Suction hole 100 ... Notch grinding device 101 ... Wafer 102 ... Work holder 103 ... Y-axis direction moving device 104 ... X-axis direction moving device 105 ... Z-axis direction moving device 106 ... Notch groove 107 ... Whetstone 108 ... Motor C1-C5 ... Chamfer d ... Diameter OW ... Wafer center O (O1-O5) ... Wheel center O1'-O5 '... Terminal R1 ... Round radius of curvature of notch groove bottom circle R2 ... Radius radius of curvature TP1-TP5 … Relative tool path TPA… Air cut tool path section ΔY1, ΔY2, ΔY3, ΔY4… Y direction difference ΔZ , △ Z2, △ Z3, △ Z4 ... angle between the linear portion of the Z-direction difference theta ... notch groove.

Claims (2)

[Claims] 1. A notch grinding device for a semiconductor wafer, comprising: a grindstone rotatably supported by a grindstone table; and a driving device for linearly moving the grindstone on a plane parallel to a plate surface of the semiconductor wafer. A notch grinding apparatus for a semiconductor wafer, comprising: a work support for rotatably holding the semiconductor wafer around a center of curvature of a notch groove bottom circle. 2. A rotating grindstone is moved linearly along a V slope of a notch groove of the semiconductor wafer on a plane parallel to a plate surface of the semiconductor wafer. The method of chamfering a notch groove of a semiconductor wafer by rotating the semiconductor wafer around a center of curvature of the notch groove.