JP2014140919A - Polishing carrier and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing carrier and a polishing device for preventing a contour portion of a wafer from becoming thick in polishing, and precisely polishing the wafer.SOLUTION: A polishing carrier 1 is equipped with a work holding hole 10 having a projecting portion 12a at least at a part of an inner peripheral end surface 11. The projecting portion 12a surrounding a wafer forms a slurry sump, and slurry is easily supplied to a wafer contour portion. Therefore, the wafer can be further precisely machined.

Description

  The present invention relates to a polishing carrier and a polishing apparatus.

  Conventionally, electronic components such as piezoelectric vibrators and semiconductors are manufactured from large wafers. The wafer is processed into an electronic component after having a desired thickness by polishing the wafer with a polishing apparatus. In order to prevent breakage such as cracking and chipping of the wafer during wafer polishing, the shape of the peripheral edge of the workpiece holding hole of the polishing carrier is matched to the contour cross-sectional shape of the wafer (see, for example, Patent Document 1). In Patent Document 1, the peripheral edge of the workpiece holding hole of the polishing carrier is concave in accordance with the shape of the chamfered outline of the wafer. By increasing the contact area with the workpiece (wafer), polishing is performed. This prevents damage to the workpiece and prevents breakage such as cracking or chipping of the wafer.

JP 2000-301451 A

  In recent years, as the accuracy of devices has improved at an accelerated rate, wafers have been required to have higher parallelism, that is, to reduce thickness variations in the wafer plane. Furthermore, in order to ensure a large effective area of the wafer, high parallelism is required up to a range close to the contour. In polishing using a polishing carrier as described in Patent Document 1, as shown in FIG. 7, the outline of the wafer 20 has less retention and supply of the slurry 40 and is difficult to process. However, the processing does not proceed, and the cross-sectional shape of the wafer becomes a shape having a large outline portion (FIG. 8), and it is difficult to perform high-precision polishing.

  The present invention has been made in order to solve at least a part of the above-described problems, and prevents a wafer from becoming thicker and a polishing carrier for polishing a wafer with high accuracy. An object is to provide a polishing apparatus.

[Application Example 1]
The polishing carrier of this application example includes a workpiece holding hole having a convex portion on at least a part of the inner peripheral end surface.
According to this application example, the slurry can be held outside the contour of the wafer (work) being polished, and the slurry necessary for polishing the wafer contour is supplied, so that the processing of the contour proceeds smoothly. It is possible to prevent the outline portion from remaining thicker than the wafer center side.

Application Example 2 In the polishing carrier of the above application example, it is preferable that the convex portion is sandwiched between concave portions in the thickness direction of the polishing carrier.
According to this application example, it is possible to provide convex portions that are slurry reservoirs on both the front and back sides of the wafer being polished, so that the processing of the contour portion can be smoothly performed on both sides of the wafer. Therefore, the wafer can be processed with higher accuracy.

Application Example 3 In the polishing carrier according to the application example described above, it is preferable that the convex portion is disposed along the inner peripheral direction of the workpiece holding hole.
According to this application example, since the convex portion which is the slurry reservoir portion surrounds the wafer being polished, the fluidity of the slurry is improved, and the slurry is more easily supplied to the contour portion of the wafer. Therefore, the wafer can be processed with higher accuracy. Also, when the shape of the wafer and the workpiece holding hole of the polishing carrier are square or the like, even if the wafer cannot be freely rotated (rotated) in the workpiece holding hole as in the case of a circle, the wafer contour The slurry can be supplied to the whole. That is, even when the shape of the wafer and the work holding hole of the polishing carrier are square or the like, the wafer can be processed with high accuracy.

Application Example 4 In the polishing carrier of the application example described above, it is preferable that the convex portion is close to one side in the thickness direction of the polishing carrier.
According to this application example, the depth of the concave portion aligned with the convex portion in the workpiece holding hole, that is, the depth of the slurry reservoir, that is, the length in the thickness direction of the polishing carrier can be provided, and the contour portion of the wafer can be processed. Can be further promoted. Therefore, for example, it is possible to correct the thickness shape of the contour portion of the wafer once the contour portion is thickened after processing.

Application Example 5 In the polishing carrier according to the application example described above, it is preferable that the tip of the convex portion has a straight line along the thickness direction.
According to this application example, since the tip of the convex portion and the contour end surface of the wafer can be in contact with each other, the polishing carrier can be pressed along the in-plane direction of the wafer, and the processing amount is uneven in the wafer surface. Therefore, the wafer can be processed with higher accuracy.

Application Example 6 In the polishing carrier according to the application example described above, an angle at which the tangent line of the side surface of the convex portion and the tangent line of the bottom portion of the concave portion connected to the side surface intersect along the thickness direction of the polishing carrier is an obtuse angle. It is preferable that
According to this application example, the slurry of the convex portion, which is the slurry reservoir, easily flows in the thickness direction of the polishing carrier and the fluidity of the slurry is improved, so that the wafer can be processed with higher accuracy.

Application Example 7 A polishing apparatus comprising the polishing carrier according to the application example described above.
According to this application example, the slurry can be held outside the contour of the wafer being polished, and the slurry necessary for polishing the wafer contour can be supplied. It can be prevented that the contour portion remains thicker than the side.

3 is a flowchart showing a procedure of a wafer processing method according to the first embodiment. 1A is a plan view of a carrier according to the first embodiment, and FIG. 2B is a partial cross-sectional view of a carrier and a state in which a wafer is disposed in a workpiece holding hole and is polished in a thickness direction. Figure. The fragmentary sectional view which shows the thickness shape of a wafer when it grind | polishes using the carrier which concerns on Embodiment 1. FIG. The fragmentary sectional view which looked at the state where the wafer of Embodiment 2 and the wafer are arranged in the work holding hole and are polished, in the thickness direction. The fragmentary sectional view which looked at the state by which the wafer of Embodiment 3 and the wafer are arrange | positioned at the workpiece | work holding hole, and were grind | polished in the thickness direction. The perspective view of the polish device provided with the career of an embodiment. The fragmentary sectional view which looked at the state where the conventional grinding | polishing carrier and the wafer were arrange | positioned at the workpiece holding hole, and were grind | polished in the thickness direction. Schematic which shows the thickness shape of a wafer when grind | polishing using the conventional grinding | polishing carrier.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is different from the actual scale so that each member can be recognized.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the accompanying drawings.
First, the wafer processing method according to Embodiment 1 of the present invention will be described.
FIG. 1 is a flowchart showing a procedure of a wafer processing method according to Embodiment 1 of the present invention. This wafer processing method is a method for manufacturing a polished wafer by polishing a crystal wafer.

First, an artificial quartz is prepared, and a lambard process, which is a grinding process performed to clarify the crystal axis of the quartz, is performed on the artificial quartz (step S1).
Next, the artificial quartz after the lumbar processing is sliced into a thin plate having a thickness of about 150 μm at a necessary angle with respect to the crystal axis to generate a plurality of wafers (step S2).

Next, the outer shape of the wafer is processed (step S3). In this embodiment, it is processed into a disk shape having a diameter of about 3 inches. In addition, it is not limited to a disk shape, For example, you may process into the plate shape which has a curved surface (R shape) in the square shape, for example, a square plate shape, or a rectangular corner.
Next, lapping (polishing) is performed on the surface of the wafer so as to have a thickness of about 100 μm (step S4).

  Next, double-side polishing processing (double-side polishing processing) of the wafer is performed using the polishing pad (step S5). This polishing is performed until the thickness of the wafer reaches about 60 μm.

Next, the double-sided polishing process (step S5) of this embodiment will be described in detail.
FIG. 2 is a diagram of double-sided polishing according to the first embodiment. 2A is a plan view of the carrier, and FIG. 2B is a thickness direction in which the wafer 20 is disposed in the carrier 1 and the workpiece holding hole 10 and both surfaces thereof are polished by the polishing pad 30. It is the fragmentary sectional view seen from.
The carrier 1 as a polishing carrier is provided with a plurality of work holding holes 10 penetrating in the thickness direction.
In the work holding hole 10, convex portions 12 a and a plurality of concave portions 13 are provided on the inner peripheral end surface 11 side by side in the thickness direction of the carrier 1. The convex portion 12 a is sandwiched between the concave portions in the thickness direction of the carrier 1 and further connected by the inner peripheral end surface 11. In addition, the convex part 12a may be provided in a part of the inner peripheral end surface 11.
The tip portion 14 of the convex portion 12 a is in contact with the contour end surface of the wafer 20 and presses the wafer 20. That is, the wafer 20 is held in the work holding hole 10. The recess 13 is provided on the inner peripheral end face 11 on the open end face side of the front and back of the work holding hole 10.

  Since the thickness of the wafer 20 after polishing is as extremely small as about 60 μm, and it is difficult to make the thickness of the carrier 1 smaller than that for reasons of material strength, the thickness after polishing of the wafer 20 may be set to about 60 μm. Good. In the first embodiment, the thickness of the carrier 1 is 60 μm.

Slurry 40 (that is, polishing liquid) can be held in the recess 13 as a slurry reservoir, and is supplied while being wound between the contour of the wafer 20 and the polishing pad 30. Thereby, the process of the outline part of the wafer 20 progresses smoothly, and it can prevent that an outline part remains thicker than the center side of the wafer 20 like the past. Therefore, it is possible to process the wafer 20 with good in-plane thickness variation (that is, a wafer with good parallelism) up to the vicinity of the wafer contour.
FIG. 3 shows the thickness shape, that is, the parallelism shape of the wafer 20 polished using the carrier 1 of the present embodiment. In this case, one side is displayed in a flat plane, and the size of PV (peak-to-valley) is thickness variation, that is, parallelism. In the first embodiment, the effective area of the wafer 20 is 1 mm from the contour edge, and the parallelism is 0.2 μm.

(Embodiment 2)
FIG. 4 is a diagram of double-sided polishing according to the second embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified here.
The workpiece holding hole 10 of the carrier 1 is provided with a convex portion 12 b and a concave portion 13 side by side in the thickness direction of the carrier 1 on the inner peripheral end surface 11 thereof. The concave portion 13 is provided only on one side in the thickness direction, that is, the convex portion 12b is close to the other side (one side). In this case, the length of the concave portion 13 in the thickness direction of the carrier 1 can be increased. Thereby, the quantity of the slurry 40 hold | maintained at the recessed part 13 can be increased, and the process of the outline part of the wafer 20 can be promoted more. Therefore, for example, the thickness shape of the contour portion of the wafer 20 once processed and thickened can be corrected. In Embodiment 2, a wafer having a parallelism of 0.4 μm could be processed (corrected) to a parallelism of 0.2 μm.

(Embodiment 3)
FIG. 5 is a diagram of double-sided polishing according to the third embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified here.
The workpiece holding hole 10 of the carrier 1 is provided with a convex portion 12 c and a plurality of concave portions 13 side by side in the thickness direction of the carrier 1 on the inner peripheral end surface 11 thereof. The angle at which the tangent of the side surface of the convex portion 12c and the tangent of the bottom portion of the concave portion 13 connected to the side surface intersect along the thickness direction of the carrier 1 is an obtuse angle. Thereby, the slurry 40 in the concave portion 13 which is a slurry reservoir portion easily flows in the thickness direction of the carrier 1 and the fluidity of the slurry 40 is improved, so that the wafer can be processed with higher accuracy. In this case, the same effect can be obtained even in a shape in which the tip portion of the convex portion 12c does not have a flat portion and is sharp like a ridgeline of a mountain.

  In addition, although demonstrated as double-sided polish processing in embodiment mentioned above, it is not limited to this, You may use the carrier 1 of this embodiment by lapping. Moreover, you may use the carrier 1 of this embodiment not only for double-sided polishing but for single-sided polishing.

(Polishing equipment)
FIG. 6 shows a polishing apparatus 50 including the carrier 1 of the above-described embodiment. According to the polishing apparatus 50, the slurry 40 (not shown) can be held outside the contour of the wafer 20 being polished, and the slurry 40 necessary for polishing the contour portion of the wafer 20 is supplied. The processing of the contour portion proceeds smoothly, and the contour portion can be prevented from remaining thicker than the center side of the wafer 20.

  In the above-described embodiment, artificial quartz is used as the material of the wafer. However, the material is not limited to artificial quartz, and any material such as silicon, oxide, ceramic, glass, and aluminum can be used. Further, it may be a composite substrate in which wiring is formed on the surface.

  DESCRIPTION OF SYMBOLS 1 ... Polishing carrier, 10 ... Work holding hole, 11 ... Inner peripheral end surface, 12a, 12b, 12c ... Convex part, 13 ... Concave part, 14 ... Tip part, 20 ... Wafer, 30 ... Polish pad, 40 ... Slurry (polishing) Liquid), 50... Polishing apparatus.

Claims (7)

  A polishing carrier comprising a workpiece holding hole having a convex portion on at least a part of an inner peripheral end surface.   The polishing carrier according to claim 1, wherein the convex portion is sandwiched between concave portions in the thickness direction of the polishing carrier.   The polishing carrier according to claim 1, wherein the convex portion is disposed along an inner circumferential direction of the workpiece holding hole.   The polishing carrier according to any one of claims 1 to 3, wherein the convex portion is closer to one side in the thickness direction of the polishing carrier.   The polishing carrier according to any one of claims 1 to 4, wherein a tip portion of the convex portion has a straight line extending in a thickness direction.   The angle at which the tangent of the side surface of the convex portion and the tangent line of the bottom portion of the concave portion connected to the side surface intersect along the thickness direction of the polishing carrier is an obtuse angle. The polishing carrier according to claim 1.   A polishing apparatus comprising the polishing carrier according to any one of claims 1 to 6.

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