Method for manufacturing carrier plate for double-sided polishing device, double-sided polishing method of workpiece, and carrier plate for double-sided polishing device

Abstract

To provide a method for manufacturing a carrier plate for a double-sided polishing device and a double-sided polishing method of workpiece, which can accurately control the shape of workpiece after double-sided polishing.SOLUTION: A method for manufacturing a carrier plate for a double-sided polishing device includes a thickness adjustment step of polishing a carrier plate 10 for a double-sided polishing device before a holding hole 11 holding workpiece is formed, and adjusting the carrier plate 10 into a predetermined thickness. A double-sided polishing method of workpiece performs double-sided polishing of workpiece, using the carrier plate 10 subjected to a holding hole formation step, after the thickness adjustment step. The carrier plate 10 for the double-sided polishing device forms one or more holding holes 11 for holding the workpiece, wherein the thickness over the whole surface thereof is substantially constant.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a carrier plate for a double-sided polishing apparatus, a method for double-sided polishing a workpiece, and a carrier plate for a double-sided polishing apparatus.

Background Art

[0002] For example, in the double-sided polishing of a workpiece such as a semiconductor wafer, in order to control the roll-off amount of the workpiece caused by the viscoelasticity of the polishing pad and the polishing action of the polishing slurry, polishing is generally performed until the workpiece and the carrier plate have approximately the same thickness (dimension polishing).

[0003] In dimension polishing, since the accuracy of the thickness of the carrier plate used for double-sided polishing is an important factor in the flatness of the workpiece after double-sided polishing, the carrier plate used for double-sided polishing is polished to adjust its thickness (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, it has been found that even when using a carrier plate with adjusted thickness, the outer peripheral portion of the workpiece after double-sided polishing may roll off more than a desired state such as a dimensioned state.

[0006] An object of the present invention is to provide a method for manufacturing a carrier plate for a double-sided polishing apparatus, a method for double-sided polishing a workpiece, and a carrier plate for a double-sided polishing apparatus that can accurately control the shape of the workpiece after double-sided polishing.

Means for Solving the Problems

[0007] The inventors diligently studied to find out the cause why, even when using a carrier plate with adjusted thickness, the workpiece after double-sided polishing may roll off more than a desired state such as a dimensionally stable state. As a result, when polishing the carrier plate to adjust its thickness, roll-off due to polishing occurred in the portion around the holding hole partitioned in the holding hole for holding the workpiece, and using the carrier plate with this roll-off to perform double-sided polishing of the workpiece was found to be the cause why the result of double-sided polishing of the workpiece did not become a desired state such as dimensionally accurate polishing and the workpiece after double-sided polishing rolled off more than the desired state.

[0008] The present invention has been made based on the above findings, and its main configuration is as follows. (1) A method for manufacturing a carrier plate for a double-sided polishing apparatus, characterized by including a thickness adjustment step of polishing a carrier plate for a double-sided polishing apparatus before forming a holding hole for holding a workpiece and adjusting it to a predetermined thickness.

[0009] (2) The method for manufacturing a carrier plate for a double-sided polishing apparatus according to (1) above, further including a holding hole forming step of forming one or more of the holding holes for holding the workpiece in the carrier plate having the thickness adjusted by the thickness adjustment step.

[0010] (3) The method for manufacturing a carrier plate for a double-sided polishing apparatus according to (1) or (2) above, wherein the carrier plate is made of resin.

[0011] (4) After performing a thickness adjustment step of polishing a carrier plate for a double-sided polishing apparatus before forming a holding hole for holding a workpiece and adjusting it to a predetermined thickness, one or more of the holding holes for holding the workpiece are formed in the carrier plate having the thickness adjusted by the thickness adjustment step, and a holding hole forming step is performed. A method for double-sided polishing of a workpiece, characterized by performing double-sided polishing of the workpiece using the carrier plate after the holding hole forming step is performed after the thickness adjustment step.

[0012] (5) The carrier plate is made of resin, and the method for double-sided polishing of the workpiece according to (4) above.

[0013] (6) One or more holding holes for holding the workpiece are formed, A carrier plate for a double-sided polishing apparatus, characterized in that the thickness is substantially constant over the entire surface.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a method for manufacturing a carrier plate for a double-sided polishing apparatus, a method for double-sided polishing of a workpiece, and a carrier plate for a double-sided polishing apparatus that can accurately control the shape of the workpiece after double-sided polishing.

Brief Description of the Drawings

[0015]

Figure 1A

Figure 1B

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be exemplified and described in detail with reference to the drawings.

[0017] FIG. 1A is a flowchart from the preparation of a conventional carrier plate to the double-sided polishing of a workpiece. As shown in FIG. 1A, in the conventional flow, a carrier plate 100 for a double-sided polishing apparatus is prepared, and then one or more holding holes 101 for holding a workpiece are formed in the carrier plate 100. Next, the carrier plate 100 for the double-sided polishing apparatus after forming the holding holes 101 for holding the workpiece is polished. Thereafter, using the carrier plate 100 (polished after forming the holding holes 101), the double-sided polishing of the workpiece (wafer) is performed.

[0018] <Method for manufacturing a carrier plate for a double-sided polishing apparatus> FIG. 1B is a flowchart from the preparation of the carrier plate in the present disclosure to the double-sided polishing of the workpiece. In the method for manufacturing a carrier plate for a double-sided polishing apparatus according to an embodiment of the present invention, as shown in FIG. 1B, first, a carrier plate 10 for a double-sided polishing apparatus (hereinafter, also simply referred to as a carrier plate) is prepared. The carrier plate 10 is preferably made of resin in view of ease of processing and the like.

[0019] Next, the carrier plate 10 before forming the holding holes 11 for holding the workpiece (in this example, a wafer) is polished and adjusted to a predetermined thickness (thickness adjustment step). Hereinafter, this thickness adjustment step will be exemplified and described. FIG. 2 is a diagram showing an example of a double-sided polishing apparatus for a workpiece and for adjusting the thickness of a carrier plate according to an embodiment of the present invention.

[0020] As shown in FIG. 2, this double-sided polishing apparatus 1 includes a rotating platen 4 having an upper platen 2 and a lower platen 3 facing each other, a sun gear 5 provided at the rotation center of the rotating platen 4, and an internal gear 6 provided annularly at the outer peripheral portion of the rotating platen 4. As shown in FIG. 2, polishing pads 7 are respectively attached to the opposing surfaces of the upper and lower rotating platens 4, that is, the lower surface side which is the polishing surface of the upper platen 2 and the upper surface side which is the polishing surface of the lower platen 3.

[0021] Further, the double-sided polishing apparatus 1 includes one carrier plate 10 shown in the example in between an upper surface plate 2 and a lower surface plate 3. In the example shown in the figure, this double-sided polishing apparatus 1 has only one carrier plate 10, but it may have a plurality of carrier plates 10.

[0022] The double-sided polishing apparatus 1 is a planetary gear type double-sided polishing apparatus that can cause the carrier plate 10 to perform a planetary motion of revolution and rotation by rotating a sun gear 5 and an internal gear 6.

[0023] In the thickness adjustment step of adjusting the thickness of the carrier plate 10, while supplying polishing slurry, the carrier plate 10 is made to perform a planetary motion, and at the same time, the upper surface plate 2 and the lower surface plate 3 are rotated relative to the carrier plate 10, so that the polishing pad 7 attached to the upper and lower rotating surface plates 4 and the carrier plate 10 are slid to adjust the thickness of the carrier plate 10.

[0024] Next, one or more holding holes 11 for holding a workpiece are formed in the carrier plate 10 having the thickness adjusted by the thickness adjustment step (holding hole forming step). The formation of this holding hole can be performed by any known mechanical grinding process or laser cutting process. Hereinafter, the effects of the manufacturing method of the carrier plate for the double-sided polishing apparatus of the present embodiment will be described.

[0025] The manufacturing method of the carrier plate for a double-sided polishing apparatus according to this embodiment includes a thickness adjustment step of polishing the carrier plate 10 for a double-sided polishing apparatus before forming the holding holes 11 for holding the workpiece and adjusting it to a predetermined thickness. As described above, thereafter, a holding hole forming step of forming one or more holding holes 11 for holding the workpiece in the carrier plate 10 having the thickness adjusted by the thickness adjustment step can be performed. At the time of the thickness adjustment step of the carrier plate, since the holding holes 11 are not formed, roll-off near the holding holes 11 does not occur due to the polishing of the carrier plate 10. Therefore, since double-sided polishing of the workpiece can be performed using the carrier plate 10 in which roll-off near the holding holes 11 does not occur, it is also possible to prevent undesired roll-off from occurring in the workpiece after double-sided polishing. As described above, according to the manufacturing method of the carrier plate for a double-sided polishing apparatus of this embodiment, the shape of the workpiece after double-sided polishing can be accurately controlled.

[0026] <Method for Double-Sided Polishing of Workpiece> Next, a method for double-sided polishing of a workpiece according to an embodiment of the present invention will be described. The method for double-sided polishing of a workpiece according to this embodiment can be executed using a double-sided polishing apparatus 1 as shown in FIG. 2, for example.

[0027] When polishing the workpiece, the workpiece is held in the holding holes 11, and the polishing pads 7 attached to the upper and lower rotating platens 4 and both sides of the workpiece held in the holding holes 11 of the carrier plate 10 are slid to polish both sides of the workpiece simultaneously. The workpiece can be, for example, a wafer, and particularly a silicon wafer.

[0028] The double-sided polishing method of this embodiment performs a thickness adjustment step of polishing the carrier plate for a double-sided polishing apparatus before forming the holding holes for holding the workpiece and adjusting it to a predetermined thickness, and then performs a holding hole forming step of forming one or more holding holes 11 for holding the workpiece in the carrier plate 10 having the thickness adjusted by the thickness adjustment step. That is, after the thickness adjustment step, double-sided polishing of the workpiece is performed using the carrier plate 10 in which the holding hole forming step has been performed. According to the double-sided polishing method of the present embodiment, at the time of the thickness adjustment process of the carrier plate, since the holding holes 11 are not formed, roll-off near the holding holes 11 does not occur due to the polishing of the carrier plate 10. Therefore, since the double-sided polishing of the workpiece can be performed using the carrier plate 10 in which roll-off near the holding holes 11 does not occur, it is also possible to prevent the occurrence of undesired roll-off on the workpiece after double-sided polishing. As described above, according to the double-sided polishing method of the workpiece of the present embodiment, the shape of the workpiece after double-sided polishing can be accurately controlled.

[0029] Also in the double-sided polishing method of the workpiece, the carrier plate is preferably made of resin.

[0030] <Carrier plate> The carrier plate 10 for a double-sided polishing apparatus according to an embodiment of the present invention is formed with one or more holding holes 11 for holding a workpiece. And, as shown also in the examples described later, the thickness is substantially constant over the entire surface.

Examples

[0031] To confirm the effects of the present invention, a comparison was made between a conventional example in which the thickness of the carrier plate was adjusted by the conventional flow shown in FIG. 1A and the double-sided polishing of the silicon wafer was performed, and an inventive example in which the thickness of the carrier plate was adjusted by the flow of the present disclosure shown in FIG. 1B and the double-sided polishing of the silicon wafer was performed, in terms of the shape of the carrier plate and the shape of the silicon wafer after polishing. A general resin-made carrier plate was used, and a general double-sided polishing apparatus was also used.

[0032] As a carrier cross-section measuring instrument, a laser displacement meter (manufactured by KYENCE) model: SI-F10 was used. Also, for measuring the wafer processing results, WaferSight (manufactured by KLA) was used.

[0033] Figure 3 is a diagram showing the shape of the carrier plate after thickness adjustment. As shown in Figure 3, in the conventional example, roll-off occurred near the holding hole, but in the inventive example, roll-off did not occur near the holding hole. In Figure 3, the horizontal axis represents the distance (mm) with the center of the holding hole as 0, and the vertical axis represents the change amount (μm) of the thickness of the carrier plate when the thickness of the carrier plate at a position 5 mm outside the outer periphery of the holding hole is set to 0.

[0034] Figure 4 is a diagram showing the relationship between the distance from the outer periphery of the holding hole and the thickness of the carrier plate. As shown in Figure 4, measurements were taken in 8 directions on the outer periphery of the holding hole of the carrier plate. As shown in Figure 4, in the conventional example, a sharp sag occurred near 1 mm from the outer periphery of the holding hole of the carrier plate (indicated by "A"), but in the inventive example, such a sag did not occur. Also, in the conventional example, a slope occurred toward the holding hole, and a gentle sag also occurred near 5 mm from the outer periphery of the holding hole of the carrier plate (indicated by "B"), but in the inventive example, such a sag did not occur. The carrier plate of the inventive example had a substantially constant thickness over the entire surface. In Figure 4, the vertical axis represents the change amount (μm) of the thickness of the carrier plate when the thickness of the carrier plate at a position 5 mm outside the outer periphery of the holding hole is set to 0.

[0035] Figure 5 is a diagram showing the outer peripheral shape of the polished silicon wafer. As shown in Figure 5, in the conventional example, a sharp sag occurred in the outer peripheral portion of the silicon wafer, but in the inventive example, the sag was smaller compared to that.

[0036] Figure 6 is a diagram showing the measurement results of ESFQR_Max (Length 30 mm, outer periphery excluded region 1 mm) of the polished silicon wafer. The vertical axis shows the measurement results at a position 30 mm in length and 1 mm from the outer periphery. As shown in Figure 6, it can be seen that the flatness of the outer peripheral portion of the silicon wafer in the inventive example was improved compared to the conventional example.

[0037] (Contribution to SDGs) Conventionally, when adjusting the thickness of the carrier plate, since holding holes were formed, a dummy member (dummy wafer) was filled in the holding holes and double-sided polishing was performed. In order to accurately adjust the thickness of the carrier plate, strict management of the thickness of the dummy member was required, so the replacement frequency of the dummy member was high. According to the present disclosure, when adjusting the thickness of the carrier plate, since no holding holes are formed, the dummy member becomes unnecessary. Thus, according to the present disclosure, it is possible to contribute to reducing the environmental load by eliminating the use of the dummy member.

Explanation of Reference Numerals

[0038] 1: Double-sided polishing apparatus, 2: Upper platen, 3: Lower platen, 4: Rotating platen, 5: Sun gear, 6: Internal gear, 7: Polishing pad, 10: Carrier plate for double-sided polishing apparatus, 11: Holding hole, 100: Carrier plate for double-sided polishing apparatus, 101: Holding hole

Claims

1. A method for manufacturing a carrier plate for a double-sided polishing apparatus, comprising a thickness adjustment step of polishing a carrier plate for a double-sided polishing apparatus before forming a holding hole for holding a workpiece and adjusting it to a predetermined thickness.

2. The method for manufacturing a carrier plate for a double-sided polishing apparatus according to claim 1, further comprising a holding hole forming step of forming one or more of the holding holes for holding the workpiece in the carrier plate having the thickness adjusted by the thickness adjustment step.

3. The method for manufacturing a carrier plate for a double-sided polishing apparatus according to claim 1 or 2, wherein the carrier plate is made of resin.

4. After performing a thickness adjustment step of polishing a carrier plate for a double-sided polishing apparatus before forming a holding hole for holding a workpiece and adjusting it to a predetermined thickness, one or more of the holding holes for holding the workpiece are formed in the carrier plate having the thickness adjusted by the thickness adjustment step, A method for double-sided polishing of a workpiece, characterized in that double-sided polishing of the workpiece is performed using the carrier plate on which the holding hole forming step has been performed after the thickness adjustment step.

5. The method for double-sided polishing of a workpiece according to claim 4, wherein the carrier plate is made of resin.

6. One or more holding holes for holding a workpiece are formed, A carrier plate for a double-sided polishing apparatus, characterized in that the thickness is substantially constant over the entire surface.

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