JP3600773B2 - Wafer edge polishing equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wafer edge polishing apparatus for polishing an outer peripheral end face of a wafer having a crystal orientation display section.
[0002]
[Prior art]
In recent years, the demand for oxide wafers and crystal wafers has been increasing as component elements for various electronic devices such as mobile phones, and high processing accuracy is also required. Further, it is required to process the wafer thinner (for example, 120 to 380 μm) depending on the application.
[0003]
[Problems to be solved by the invention]
However, when the wafer is thinned, cracks or chips are generated in a processing step, for example, a polishing step or a cleaning step, which is a factor that deteriorates the yield.
[0004]
On the other hand, it is known that the occurrence of such cracks and chips can be prevented to some extent by increasing the surface roughness of the outer peripheral end surface of the wafer, and therefore, the outer peripheral end surface of the wafer is also subjected to diamond grinding. However, in this diamond grinding, micro cracks are generated on the edge of the outer peripheral end face, and it is not a very effective means for preventing the occurrence of cracks and chips.
[0005]
The present invention has been proposed in view of the above, and it is possible to increase the surface roughness of the outer peripheral end surface of a wafer without occurrence of microcracks, and to prevent the occurrence of cracks and chipping of the wafer by improving the surface roughness. It is an object of the present invention to provide a wafer edge polishing apparatus capable of improving the yield by using the method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is directed to a wafer edge polishing apparatus for polishing an outer peripheral end face of a wafer having a crystal orientation display section, wherein the wafers are stacked with the crystal orientation display sections aligned. A work setting part which is set horizontally and the laminated wafer is rotatable about an axis, and a lamination direction of the wafer laminated on the work setting part is parallel to the axis, and the outer peripheral surface of the laminated wafer has two axes. Two cylindrical or cylindrical polishing brushes horizontally arranged so as to face each other, a brush rotation driving unit for rotating the polishing brush around an axis, and a brush reciprocating driving unit for reciprocating the polishing brush in the axial direction If, anda brush follower drive unit for pressing the outer peripheral surface of the laminated wafer while tracking the polishing brush to the outer peripheral shape of the wafer stack, the bra The rotary drive unit, the brush reciprocating drive unit and the brush following drive unit are provided corresponding to each of the two polishing brushes, and are configured on each moving table movable in a direction perpendicular to the axis of the laminated wafer, The brush following drive unit includes a copying cam provided in a shape similar to the wafer and concentric with the axis of the laminated wafer, and abutting the outer periphery of the copying cam in two directions to transmit the displacement of the copying cam to each moving table. Each of the two polishing brushes is pushed toward the axis side of the laminated wafer by the movement of the moving table, and the rotation of the laminated wafer is transmitted to the moving table via the copying cam and the arm. moving table by displacing in a direction perpendicular to the axis of the laminated wafers to move following the outer peripheral shape of the wafer stack, to rotate the laminated wafers Te, the polishing The brush is rotated while reciprocating, and so as to polish the outer peripheral surface of the laminated wafer polishing brush by following the outer peripheral shape of the wafer stack from two directions, and characterized in that.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0008]
FIG. 1 is a perspective view schematically showing the entire configuration of a wafer edge polishing apparatus of the present invention, FIG. 2 is a plan view of the wafer edge polishing apparatus of the present invention, FIG. 3 is a vertical sectional view taken along line II of FIG. 2, and FIG. 2 is a vertical sectional view taken along the line II-II of FIG. 2, FIG. 5 is a front view of the wafer edge polishing apparatus of the present invention, and FIG. 6 is an explanatory view of a wafer and a laminated wafer.
[0009]
In these figures, a wafer edge polishing apparatus 1 of the present invention is an apparatus for polishing an outer peripheral end surface 2a of a wafer 2, and includes a work setting section 3, two polishing brushes 4, 4, brush rotation driving sections 5, 5, , Brush reciprocating drive units 6, 6 and brush following drive units 7, 7. Note that the wafer edge polishing apparatus 1 is configured to be substantially axially symmetric in plan view and front view (back view). Therefore, here, the configuration on one side will be described, and the configuration on the other side will be the same as the same component. The description is omitted by attaching the reference numerals.
[0010]
The wafer edge polishing apparatus 1 is built on a base 10 or a machine frame 11, and the base 10 is provided with an X-direction moving table 8 that moves on rails 8a and 8b. A Y-direction moving table 9 that moves on 9a and 9b is provided. The brush rotation driving unit 5 and the brush following driving unit 7 are configured on an X-direction moving table 8 and a Y-direction moving table 9.
[0011]
As shown in FIG. 6, a crystal orientation display portion (hereinafter, referred to as “orientation flat”) 2b is formed on the wafer 2 as a work to display a crystal orientation by partially cutting out the outer peripheral end surface 2a. The orientation flats 2b are made to coincide with each other, and the laminated wafer 2 is set as a laminated wafer 20 in the work setting section 3. This wafer 2 is, for example, an oxide wafer or a quartz wafer.
[0012]
The work setting section 3 is for laminating and setting the wafers 2 with the orientation flats 2b aligned with each other, and for rotating the laminated wafers 20 around an axis. As shown in FIG. The rotational drive of a motor 30 mounted on the rear wall 12 on the base 10 is transmitted to a rotary shaft 31 via a belt. At the front end of the rotating shaft 31, a work holding portion 32 is provided. When setting the above-mentioned laminated wafer 20 on the work holding part 32, first loosen the screw 32a at the tip of the work holding part 32 to widen the interval between the clamping arms 33, 33, and then put the laminated wafer 20 in the space. The wafer is carried in using a transfer jig (not shown), and then the screw 32a is tightened to narrow the interval between the clamping arms 33, 33, whereby the laminated wafer 20 is directly clamped and fixed between the clamping arms 33, 33. In this manner, the laminated wafer 20 is set on the work holding portion 32, and the laminated wafer 20 is rotated by the motor 30 and is rotated integrally with the rotating shaft 31 by the bearing mechanism.
[0013]
The polishing brush 4 has a configuration in which, for example, a plurality of brushes are arranged in parallel on the outer peripheral surface of a cylindrical or cylindrical SUS drum, and the brushes are innumerable. Are densely assembled. Therefore, when the polishing brush 4 is used, the brush material is constantly in contact with the surface of the work from a plurality of directions, so that fine vertical lines due to brush bristles are not generated on the surface of the work, and the work is evenly and precisely finished. Polishing becomes possible.
[0014]
The brush rotation drive unit 5 is for rotating the polishing brush 4 about an axis. The brush rotation drive unit 5 is provided with a shaft support unit 52 for horizontally supporting the drive shaft 51 on the Y-direction moving table 9, and one side wall of the shaft support unit 52. The rotational drive of a motor 54 attached to 53 is transmitted to a drive shaft 51 via a belt 55. The polishing brush 4 is mounted horizontally in a state where the polishing brush 4 is covered with a cover 56 near the tip of the drive shaft 51. Then, a part of the cover 56 is removed so that the polishing brush 4 faces the laminated wafer 20 set on the work setting section 3 and can come into direct contact therewith.
[0015]
The brush reciprocating drive unit 6 reciprocates the polishing brush 4 in the axial direction. The brush reciprocating drive unit 6 includes a motor 61 separately disposed near the rear end of the Y-direction moving table 9. The rear end of the connecting arm 62 is rotatably connected, and the front end of the connecting arm 62 is rotatably connected to the Y-direction moving table 9. Accordingly, the rotational drive of the motor 61 is converted into linear motion by the connecting arm 62, and the linear motion causes the Y-direction moving table 9 to reciprocate along the Y-axis. Reciprocate along the Y-axis via
[0016]
The brush following drive unit 7 presses the polishing brush 4 against the outer peripheral surface of the laminated wafer 20 while following the outer peripheral shape of the laminated wafer 20, and includes an air cylinder 71 below the X-direction moving table 8. As shown in FIG. 5, the air cylinder 71 has a piston 71a connected to an X-direction moving table 8 via a connecting piece 71b. Reciprocating along. A copying cam 34 similar in shape to the wafer 2 is provided concentrically at the rear end of the rotating shaft 31 of the work setting section 3, and one end of the copying cam 34 swings on the X-direction moving table 8. The other end of the freely connected arm 72 abuts. Under this configuration, when the piston 71a of the air cylinder 71 extends and the X-direction moving table 8 moves in the direction of the rotating shaft 31, the Y-direction moving table 9 and the shaft support 52 move integrally with the movement, The polishing brush 4 moves in the direction of the rotating shaft 31 together with the driving shaft 51 to come into contact with the laminated wafer 20. On the other hand, when the rotating shaft 31 rotates, the arm 72 is displaced by the copying cam mechanism according to the outer peripheral shape of the copying cam 34, and the displacement is transmitted to the X-direction moving table 8. Therefore, the polishing brush 4 is constantly elastically pushed toward the rotating shaft 31 by the pushing force of the air cylinder 71 when the piston is extended, and is affected by the displacement of the arm portion 72. As a result, the outer peripheral shape of the laminated wafer 20 is reduced. It is displaced along the X axis while following (the outer peripheral shape of the copying cam 34). That is, the polishing brush 4 performs polishing while making contact with the portion of the wafer 2 on the orientation flat 2b and other portions with substantially the same pressing force.
[0017]
In the wafer edge polishing apparatus 1 having the above-described configuration, the outer peripheral surface of the laminated wafer 20 set in the work setting section 3 is polished by pushing the piston 71 a of the air cylinder 71 so that the polishing brush 4 approaches and comes into contact with the laminated wafer 20. , By driving the motors 30, 54 and 61, respectively. At this time, the laminated wafer 20 rotates, and the polishing brush 4 rotates while reciprocating and following the outer peripheral shape of the laminated wafer 20. Therefore, the polishing brush 4 always maintains an optimal contact state with the laminated wafer 20, and polishing proceeds. During the polishing, the polishing liquid and the cleaning water are appropriately switched by a liquid supply mechanism (not shown) and supplied to the processing area.
[0018]
As described above, in the embodiment of the present invention, the polishing brush 4 is reciprocated and rotated while following the outer peripheral shape of the laminated wafer 20, and the polishing is performed in that state. The surface roughness of the outer peripheral end face 2a can be improved to achieve a mirror finish, and the polishing can be performed without generating microcracks at the wafer edge which occur during conventional diamond grinding. Therefore, the strength of the wafer 2 can be remarkably improved, and the occurrence of cracks and chips, which have conventionally occurred in handling in a polishing step, a cleaning step, and the like, can be significantly reduced, and the yield can be improved. .
[0019]
In addition, since the polishing brush 4 faces the laminated wafer 20 from two directions, the time required for polishing to a predetermined surface roughness can be halved, and the processing time can be shortened.
[0020]
In addition, since the polishing is performed by setting the laminated wafer 20 and the polishing brush 4 in a horizontal state, even if the polishing liquid or the cleaning liquid is supplied, the polishing liquid is quickly dropped and collected. Therefore, it is possible to supply the polishing liquid and the cleaning liquid promptly and uniformly, and it is possible to prevent the processing accuracy from being deteriorated due to the remaining polishing powder and the like.
[0021]
In the above description, the polishing brush 4 has a configuration in which a plurality of brushes are radially arranged on the outer circumferential surface of a SUS drum and a plurality of brushes are arranged in parallel. You may.
[0022]
Although the wafer 2 is an oxide wafer or a quartz wafer, the present invention can be applied to wafers made of other various materials.
[0023]
【The invention's effect】
Since the present invention has the above-described configuration, the following effects can be obtained.
[0024]
In this invention, a polishing brush with reciprocating rotates while following the outer peripheral shape of the wafer stack. Thus is polished in this state, to improve the surface roughness of the outer peripheral edge surface of each wafer mirror Finishing can be performed, and polishing can be performed without generating microcracks at the wafer edge which occur during conventional diamond grinding. Therefore, the strength of the wafer can be remarkably improved, and the occurrence of cracks and chips, which have conventionally occurred in handling in a polishing step, a cleaning step, and the like, can be significantly reduced, and the yield can be improved.
[0025]
Further, in the invention of this, since the polishing brush is so as to face the two directions laminated wafers, it is possible to halve the time required to polish to a predetermined surface roughness, it is possible to shorten the processing time.
[0026]
Furthermore, in the invention of this, since to perform the polishing by setting the a laminated wafer and the polishing brush in a horizontal state, is as a polishing liquid or the cleaning liquid is collected and falls quickly be supplied, thus In addition, the polishing liquid and the cleaning liquid can be supplied promptly and uniformly, and the deterioration of the processing accuracy due to the remaining polishing powder and the like can be prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing an overall configuration of a wafer edge polishing apparatus according to the present invention.
FIG. 2 is a plan view of the wafer edge polishing apparatus of the present invention.
FIG. 3 is a vertical sectional view taken along line II of FIG. 2;
FIG. 4 is a vertical sectional view taken along line II-II of FIG.
FIG. 5 is a front view of the wafer edge polishing apparatus of the present invention.
6A and 6B are explanatory views of a wafer and a laminated wafer, wherein FIG. 6A is a plan view of the wafer, and FIG. 6B is a perspective view of the laminated wafer.
[Explanation of symbols]
Reference Signs List 1 wafer edge polishing apparatus 2 wafer 2a outer peripheral end face 2b orientation flat 20 laminated wafer 3 work setting unit 30 motor 31 rotation shaft 32 work holding unit 32a screw 33 clamping arm 34 copying cam 4 polishing brush 5 brush rotation drive unit 51 drive shaft 52 shaft support Part 53 one side wall 54 motor 55 belt 56 cover 6 brush reciprocating drive part 61 motor 61a eccentric shaft 62 connecting arm 7 brush following drive part 71 air cylinder 71a piston 71b connecting piece 72 arm part 8 direction moving table 8a rail 8b rail 9 direction moving Table 9a Rail 9b Rail 10 Base 11 Machine frame 12 Rear wall

Claims (1)

In a wafer edge polishing apparatus for polishing an outer peripheral end surface of a wafer having a crystal orientation display unit,
A work setting unit that stacks the wafers in a state where the crystal orientation display units are aligned , sets the wafers horizontally, and rotates the stacked wafers around an axis;
The above and the stacking direction of the wafer laminated to the workpiece setting section axis parallel and a cylindrical or cylindrical two polishing brush was placed horizontally so as to face in two directions on an outer peripheral surface of the stacked wafers,
A brush rotation drive unit for rotating the polishing brush around an axis,
A brush reciprocating drive for reciprocating the polishing brush in the axial direction,
A brush following drive unit that presses the polishing brush against the outer peripheral surface of the laminated wafer while following the outer peripheral shape of the laminated wafer,
Has,
The brush rotation drive unit, the brush reciprocation drive unit, and the brush follow-up drive unit are provided corresponding to each of the two polishing brushes, and are configured on respective moving tables movable in a direction perpendicular to the axis of the laminated wafer. And
The brush following drive unit includes a copying cam provided in a shape similar to the wafer and concentric with the axis of the laminated wafer, and abutting the outer periphery of the copying cam in two directions to transmit the displacement of the copying cam to each moving table. With two arms,
Each of the two polishing brushes is pushed to the axis side of the laminated wafer by the movement of the moving table, and the rotation of the laminated wafer is transmitted to the moving table via the copying cam and the arm, and the moving table is moved to the axis of the laminated wafer. Is displaced in a direction perpendicular to, so as to follow the outer peripheral shape of the laminated wafer,
While rotating the laminated wafer, the polishing brush was rotated while being reciprocated , and the outer peripheral surface of the laminated wafer was polished from two directions by the polishing brush so as to follow the outer peripheral shape of the laminated wafer .
A wafer edge polishing apparatus, characterized in that:

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