WO2018163721A1

WO2018163721A1 - Carrier for double-sided polishing device

Info

Publication number: WO2018163721A1
Application number: PCT/JP2018/004856
Authority: WO
Inventors: 大地北爪; 佑宜田中
Original assignee: 信越半導体株式会社
Priority date: 2017-03-06
Filing date: 2018-02-13
Publication date: 2018-09-13

Abstract

The present invention relates to a carrier for a double-sided polishing device, the carrier having: a carrier base material in which a holding hole for holding a wafer during polishing is formed; and an insert material disposed along the inner circumference of the holding hole. In the carrier base material, an uneven part is periodically formed along the inner circumference of the holding hole, the distance between the centers of recess portions adjacent to each other in the uneven part is 10 mm to 60 mm, and the area of a protruding portion of the uneven part is larger than the area of a notch portion of the recess part. In the insert material, an uneven part, which can be fitted with the uneven part formed on the inner circumference of the holding hole, is periodically formed on the outer circumference of the insert material, and the uneven part formed on the inner circumference of the holding hole of the carrier base material is fitted with the uneven part formed on the outer circumference of the insert material. Thus, the carrier for the double-sided polishing device, in which deformation of a peripheral portion (fitting portion) of the holding hole in the carrier base material is reduced, is provided.

Description

Carrier for double-side polishing machine

The present invention relates to a carrier for a double-side polishing apparatus used in a double-side polishing apparatus that performs double-side polishing of a wafer.

In the double-side polishing apparatus, for example, about 5 wafers per batch are polished at the same time, a carrier for a double-side polishing machine having the same number of holding holes as the number of wafers is installed on the surface plate. The wafer is held by the holding holes of the carrier, the wafer is sandwiched from both surfaces by the polishing cloth provided on the upper and lower surface plates, and polishing is performed while supplying the polishing agent to the polishing surface.

In a carrier for a double-side polishing apparatus, a carrier base material having a holding hole for holding a wafer is usually made of metal. The carrier for a double-side polishing apparatus has a resin insert material on the inner periphery of the wafer holding hole in order to protect the outer peripheral portion of the wafer from the metal carrier base material. This insert material is formed by fitting or injection molding. Since the insert material is in contact with the outer peripheral portion of the wafer, it is important in making the edge shape of the wafer.

When attaching this insert material, in order to prevent the insert material from detaching during wafer processing or conveyance, the outer periphery of the insert material and the inner periphery of the holding hole of the carrier base material are fitted in a wedge shape and further bonded. It may be fixed with an agent (Patent Document 1).

JP 2000-24912 A

The wedge shape of the outer periphery of the insert material and the inner periphery of the holding hole of the carrier base material periodically exists in large numbers, and distortion may occur during processing of the carrier. Further, when the insert material is fitted, there is a case where the fitting is partially tightened due to processing accuracy, and there is a problem that the stress is locally generated and the carrier hole holding hole periphery is distorted. Further, the distortion of the fitting portion around the holding hole of the carrier base material causes deterioration of the edge shape of the wafer, and also causes a deviation between the carrier base material and the insert material.

If the wafer is processed in this state, the polishing cloth is locally deformed, resulting in deterioration of wafer flatness. In addition, the deviation between the carrier base material and the insert material can be corrected by polishing until the carrier base material and the insert material have the same height. It cannot be corrected until. As a result, this distortion causes deterioration of the edge shape of the wafer. Further, since the degree of deterioration of the edge shape changes depending on the magnitude of distortion, there is a problem in that the flatness varies among a set of five carriers. Therefore, in order to suppress the deterioration of the edge shape of the wafer and the variation in flatness between the carriers, there is a need for a carrier for a double-side polishing apparatus in which the peripheral portion of the holding hole of the carrier base material (fitting portion) is less distorted.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a carrier for a double-side polishing apparatus in which distortion of a peripheral portion (fitting portion) of a holding hole of a carrier base material is reduced.

In order to solve the above problems, the present invention provides a carrier base material provided in a double-side polishing apparatus for polishing a wafer on both sides and having a holding hole for holding the wafer during polishing, and the holding hole. A carrier for a double-side polishing apparatus, which is disposed along an inner periphery and has an insert material formed with an inner periphery contacting the outer periphery of the wafer, wherein the carrier base material is along the inner periphery of the holding hole The concave-convex portions are periodically formed, the distance between the centers of adjacent concave portions in the concave-convex portions is 10 mm or more and 60 mm or less, and the area of the convex portions in the concave-convex portions in the plane direction of the carrier base material Is larger than the area of the cutout portion of the recess, and the insert material is formed periodically with an uneven portion that can be engaged with the uneven portion formed on the inner periphery of the holding hole. The concave and convex portions formed on the inner periphery of the holding hole of the carrier base material are fitted with the concave and convex portions formed on the outer peripheral portion of the insert material. Provided is a carrier for a double-side polishing apparatus.

Such a carrier for a double-side polishing apparatus is a carrier for a double-side polishing apparatus in which the distortion of the peripheral part (fitting part) of the holding hole of the carrier base material is reduced.

In this case, the shape of the cutout portion of the recess formed in the inner periphery of the holding hole of the carrier base material may be any one of a triangle, a rectangle, a trapezoid, a wedge, a keyhole, a U-shape, and a circle. preferable.

As the shape of the cutout portion of the recess formed in the inner periphery of the holding hole of the carrier base material in the carrier for a double-side polishing apparatus of the present invention, the above shape can be mentioned.

In this case, the uneven portion formed in the inner periphery of the holding hole of the carrier base material has an area of the convex portion in the surface direction of the carrier base material that is four times or more than an area of the notch portion of the concave portion. Preferably there is.

With such a carrier for a double-side polishing apparatus, the strength of the convex portion formed on the inner periphery of the carrier hole of the carrier base material further increases, so the peripheral part of the carrier base material holding hole (fitting part) This is preferable because it provides a carrier for a double-side polishing apparatus with reduced distortion.

The carrier for the double-side polishing apparatus of the present invention can increase the strength of the fitting portion formed on the inner periphery of the holding hole of the carrier base material, and can reduce distortion around the holding hole of the carrier base material. It becomes. Then, by performing double-side polishing of the wafer using such a carrier for a double-side polishing apparatus, it is possible to obtain a wafer with improved edge flatness and reduced flatness variation due to the distortion reducing effect around the holding hole. .

It is the schematic which shows an example of the carrier for double-side polish apparatuses of this invention. It is the schematic which shows an example of the carrier for the conventional double-side polish apparatus. It is explanatory drawing explaining the distortion which generate | occur | produced in the carrier for the conventional double-side polish apparatus. It is a graph which shows the relationship between the deformation rate around the holding hole of a carrier base material, and the distance d of the center of the adjacent recessed part in the uneven | corrugated | grooved part of a carrier base material. It is explanatory drawing explaining the part which measured distortion in Example 1 and Comparative Example 1. FIG. In the measurement results of the strain amount around the holding hole (FIG. 6 (A)), ESFQRange relative value (FIG. 6 (B)), and ESFQRmax relative value (FIG. 6 (C)) measured in Example 1 and Comparative Example 1. is there. 6 is a graph showing the relationship between the strain around the holding hole of the carrier base material and the flatness (nm) in Comparative Examples 2 to 4.

As described above, conventionally, there has been a demand for a carrier for a double-side polishing apparatus with less distortion in the peripheral portion (fitting portion) of the holding hole of the carrier base material.

As a result of intensive investigations to solve the above-mentioned problems, the present inventors have found that the interval between the concave portions in the concave and convex portions formed on the inner periphery of the holding hole of the carrier base material (that is, the center of adjacent concave portions). The distance between each other) is increased from 5 mm or more to less than 10 mm to 10 mm or more and 60 mm or less, and the carrier base material is found to be a carrier in which the distortion of the fitting portion with the insert material is reduced. Reached.

That is, the present invention is arranged in a double-side polishing apparatus for double-side polishing a wafer, and is arranged along a carrier base material having a holding hole for holding the wafer during polishing and along the inner periphery of the holding hole. And a carrier for a double-side polishing apparatus having an insert material formed with an inner peripheral portion in contact with the outer peripheral portion of the wafer, wherein the carrier base material has a concavo-convex portion periodically along the inner periphery of the holding hole. The distance between the centers of adjacent recesses in the concavo-convex portion is not less than 10 mm and not more than 60 mm, and the area of the ridge in the concavo-convex portion in the surface direction of the carrier base material is a notch portion of the recess. The insert material is formed by periodically forming uneven portions that can be fitted to the uneven portions formed on the inner periphery of the holding hole on the outer periphery, A carrier for a double-side polishing apparatus, wherein the uneven portion formed on the inner periphery of the holding hole of the carrier base material is fitted with the uneven portion formed on the outer periphery of the insert material. I will provide a.

Hereinafter, the carrier for a double-side polishing apparatus of the present invention will be described in detail.

FIG. 1 shows an example of a carrier for a double-side polishing apparatus of the present invention. The carrier 1 for a double-side polishing apparatus of the present invention is disposed in a double-side polishing apparatus for double-side polishing a wafer, and includes a carrier base material 3 having a holding hole 2 for holding the wafer during polishing, The insert material 4 is disposed along the inner periphery of the holding hole 2 and has an inner peripheral portion formed in contact with the outer peripheral portion of the wafer.

The carrier base material 3 is one in which irregularities 5 are periodically and continuously formed along the inner periphery of the holding hole 2. In the present invention, the distance d between the centers of adjacent concave portions 5a in the concave and convex portion 5 of the carrier base material 3 is 10 mm or more and 60 mm or less, and the area of the convex portion 5b in the concave and convex portion 5 in the surface direction of the carrier base material 3 is It is characterized by being larger than the area of the cutout portion of the recess 5a.

Thus, by fitting the distance d between the centers of the adjacent recesses 5a in the concavo-convex part 5 of the carrier base material 3 to 10 mm or more and 60 mm or less, which is wider than the conventional distance, the carrier base material 3 is fitted to the insert material 4. Thus, the carrier 1 for a double-side polishing apparatus with reduced joint distortion is obtained.

As shown in FIG. 2, in the conventional carrier 10 for a double-side polishing apparatus, the centers of adjacent concave portions 50 a in the concave and convex portions of the carrier base material 30 are arranged in order to securely fit the insert material 40 and the carrier base material 30. Although the distance varies depending on the diameter of the wafer, many exist at relatively narrow intervals of 5 mm to less than 10 mm (about 9.6 mm when the diameter is 300 mm). However, stress is partially concentrated at such a narrow interval, and as shown in FIG. 3, distortion occurs around the holding hole of the carrier base material 30.

In the present invention, in the surface direction of the carrier base material 3, the area of the convex part 5b in the concave and convex part 5 is larger than the area of the notch part of the concave part 5a, and adjacent concave parts in the concave and convex part 5 of the carrier base material 3 By widening the distance d between the centers of 5a to 10 mm or more, the number of the concavo-convex portions 5 can be reduced as compared with the conventional case, and the area of the convex portions 5b on the carrier base material side can be relatively increased. Thus, the amount of distortion around the holding hole of the carrier base material 3 can be reduced by making the interval between the fitting portions wide. Further, if d exceeds 60 mm, insert material 4 may be detached from carrier base material 3 during wafer processing or the like, and therefore d is 60 mm or less in the present invention. Further, the distance d between the centers of adjacent recesses 5a in the concavo-convex part 5 of the carrier base material 3 is preferably 14 mm or more and 50 mm or less, more preferably 18 mm or more and 30 mm or less.

Here, regarding the relationship between the size of the distance d between the centers of adjacent concave portions in the concave and convex portions formed on the inner periphery of the holding hole of the carrier base material and the distortion of the peripheral portion of the holding hole (fitting portion) of the carrier base material, It is shown below.

About the fitting part around the holding hole of the carrier base material of the carrier for a double-side polishing apparatus for double-side polishing a silicon wafer having a diameter of 300 mm, when the distance d (9.6 mm) between the centers of the conventional adjacent recesses is Based on the amount of distortion of the carrier base material, the amount of distortion of the carrier base material when the distance d was increased to 10 times (95.5 mm) was quantified by simulation analysis (ANSY mechanical).

FIG. 4 (A) and FIG. 4 (B) show the results of analysis in the case where the shape of the notched portion of the concavo-convex part is trapezoidal and circular. As a result, in both cases of the trapezoid (FIG. 4A) and the circle (FIG. 4B), the distance d between the centers of adjacent concave portions in the concave and convex portions of the carrier base material is less than 10 mm. In this case, the amount of distortion (deformation rate) is significantly larger than in the case of 10 mm or more. On the other hand, when the distance d between the centers of the adjacent recesses is 10 mm or more, the distortion decreases as the distance d between the centers of the adjacent recesses increases. The reduction in distortion is saturated as the interval increases, and is constant at a distance of 4 times (d = 38.2 mm) or more when the shape of the notch is trapezoidal.

When the shape of the cutout portion of the recess is trapezoidal, when the deformation rate of the distance between the centers of adjacent recesses (d = 9.6 mm) is used as a reference, the distance is four times (d = 38.2 mm). The amount of distortion is reduced by 11%. Similarly, when the cutout portion of the concave portion is circular, it is constant at a distance of four times or more, and the distortion amount is reduced by 6.5% based on the deformation rate of the conventional interval.

Further, in the carrier 1 for a double-side polishing apparatus of the present invention, the shape of the cutout portion of the recess 5a formed in the inner periphery of the holding hole 2 of the carrier base material 3 is triangular, rectangular, trapezoidal, wedge-shaped, keyhole-shaped, U It is preferably either a letter shape or a circle. And in any of these shapes, as a result of simulation analysis, the same tendency as described above was found.

Moreover, as for the uneven | corrugated | grooved part 5 formed in the inner periphery of the holding hole 2 of the carrier base material 3, the area of the convex part 5b in the surface direction of the carrier base material 3 is 4 times or more of the area of the notch part of the recessed part 5a. It is preferable. With such a carrier 1 for a double-side polishing apparatus, the strength of the convex portion 5b is further increased, so that the distortion of the peripheral portion (fitting portion) around the holding hole of the carrier base material 3 is further reduced.

As shown in FIG. 1, the insert 4 has an uneven portion 6 composed of a recessed portion 6 a and a protruded portion 6 b that can be engaged with the uneven portion 5 formed on the inner periphery of the holding hole 2 of the carrier base material 3. It is formed periodically in the part. As a material of the insert material 4, for example, a hard resin can be used.

The carrier 1 for a double-side polishing apparatus of the present invention is fitted with an uneven portion 5 formed on the inner periphery of the holding hole 2 of the carrier base material 3 and an uneven portion 6 formed on the outer periphery of the insert material 4. It is a thing.

Such a carrier 1 for a double-side polishing apparatus according to the present invention has less distortion in the peripheral portion (fitting part) of the holding hole of the carrier base material 3, and the wafer 1 is double-sided using such a carrier 1 for double-side polishing apparatus. By polishing, the edge flatness of the wafer to be processed can be improved and the flatness variation can be reduced due to the distortion reducing effect around the holding hole.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

(Comparative Example 1)
As a carrier for a double-side polishing apparatus, the shape of the notched portion of the concave portion 50a of the concave and convex portion formed on the inner periphery of the holding hole of the carrier base material 30 is trapezoidal, and the distance d between the centers of the adjacent concave portions 50a is 9.6 mm. The carrier base material 30 and the insert material 40 were fitted to each other to manufacture a carrier 10 for a double-side polishing apparatus as shown in FIG.

Example 1
As a carrier for a double-side polishing apparatus, the shape of the notched portion of the concave portion 5a of the concave and convex portion 5 formed on the inner periphery of the holding hole of the carrier base material 3 is trapezoidal, and the distance d between the centers of the adjacent concave portions 5a is 19.1 mm. In the surface direction, the carrier base material 3 in which the area of the convex part 5b in the concave-convex part 5 is larger than the area of the notch part of the concave part 5a and the insert material 4 are fitted, and double-side polishing as shown in FIG. An apparatus carrier 1 was manufactured. The d (19.1 mm) of Example 1 is about twice the d (9.6 mm) of Comparative Example 1.

With respect to the carrier for the double-side polishing apparatus of Example 1 and Comparative Example 1 above, the distortion in the range shown in FIG. 5 (around the holding hole of the carrier base material) was confirmed with a three-dimensional measuring machine (manufactured by Tokyo Seimitsu). The measurement results are shown in FIG. The average value of the strain amount was 24.2 μm in Example 1 and 29.1 μm in Comparative Example 1. In Example 1, it was confirmed that the distortion around the holding hole was significantly reduced as compared with Comparative Example 1. These results almost coincided with the simulation results shown in FIG.

Furthermore, using these carriers, DSP (Double Side Polishing) processing was performed on a silicon wafer having a diameter of 300 mm, and flatness measurement was performed (LSW-3000, Kobelco). FIG. 6B shows the result of the ESFQRange relative value when Comparative Example 1 is used as a reference, and FIG. 6C shows the result of the relative value of ESFQRmax. In Example 1, the range of ESFQR range was reduced compared to Comparative Example 1, and it was confirmed that the variation in edge flatness was reduced. At the same time, the value of ESFQRmax could be improved.

(Comparative Examples 2 to 4)
The amount of distortion (magnification) around the holding hole of the carrier for the double-side polishing apparatus (Comparative Examples 2 to 4) having a different amount of distortion around the holding hole of the carrier base material when the carrier for the double-side polishing apparatus of Comparative Example 1 is used as a reference Table 1 and FIG. 7 show the relationship with the flatness deterioration amount (nm). As a result, it was confirmed that the smaller the amount of distortion, the better the flatness.

(Comparative Example 5)
In the same manner as in Comparative Example 1, as a carrier for a double-side polishing apparatus, the shape of the notched portion of the concave portion 50a of the concave and convex portion formed on the inner periphery of the holding hole of the carrier base material 30 is trapezoidal, and the centers of the adjacent concave portions 50a are The carrier base material 30 having a distance d of 62 mm and the insert material 40 were fitted together to manufacture a carrier 10 for a double-side polishing apparatus as shown in FIG.

Using the manufactured carrier, DSP processing was performed on a silicon wafer having a diameter of 300 mm. However, the insert material 40 was detached from the carrier and the DSP processing could not be performed.

As described above, when the distance d between the centers of adjacent recesses formed on the inner periphery of the holding hole of the carrier base material is less than 10 mm, the amount of distortion around the holding hole is significantly increased (Comparative Example 1). When it exceeded 60 mm, the insert material was detached during wafer processing (Comparative Example 5). On the other hand, the carrier in which d is 10 mm or more and 60 mm or less has little distortion in the peripheral portion (fitting portion) of the holding hole of the base material (Example 1). Further, when the d was 60 mm, the insert material did not come off even when the wafer was subjected to DSP processing.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Claims

A carrier base material provided in a double-side polishing apparatus for polishing a wafer on both sides and having a holding hole for holding the wafer during polishing, and arranged along the inner periphery of the holding hole, the outer periphery of the wafer A carrier for a double-side polishing apparatus having an insert material formed with an inner peripheral part in contact with the part,
The carrier base material has irregularities formed periodically along the inner periphery of the holding hole, and the distance between the centers of adjacent depressions in the irregularities is 10 mm or more and 60 mm or less, and the carrier In the surface direction of the base material, the area of the convex part in the uneven part is larger than the area of the notch part of the concave part,
The insert material is one in which an uneven portion that can be fitted to the uneven portion formed on the inner periphery of the holding hole is periodically formed on the outer peripheral portion,
For the double-side polishing apparatus, wherein the uneven portion formed on the inner periphery of the holding hole of the carrier base material is fitted with the uneven portion formed on the outer peripheral portion of the insert material. Career.
The shape of the cutout portion of the recess formed in the inner periphery of the holding hole of the carrier base material is any one of a triangle, a rectangle, a trapezoid, a wedge, a keyhole, a U-shape, and a circle. Item 2. The carrier for a double-side polishing apparatus according to Item 1.
In the uneven portion formed on the inner periphery of the holding hole of the carrier base material, the area of the convex portion in the surface direction of the carrier base material is at least four times the area of the notch portion of the concave portion. The carrier for a double-side polishing apparatus according to claim 1 or 2.