KR20170045266A - Holder and manufacturing method thereof - Google Patents

Abstract

Provided is a holder for a polishing apparatus capable of preventing edges of a polished object and falling off of a polished object from being scratched and preventing peeling of the frame material. The holding pawl 13 has a plurality of bubbles 19 in its interior and is provided with a holding pad 15 made of foamed polyurethane and a holding pad 15 formed along the periphery of the holding surface of the holding pad 15, The holding pad 15 has a stepped portion 21 formed by cutting a peripheral edge of the holding surface by a predetermined depth, and the frame member 17 Is adhered to the holding pad 15 on the horizontal plane of the step portion 21 and is fixed to the holding pad 15 so that the inner circumferential face is opposed to the vertical face of the step portion 21. [

Description

[0001] HOLDER AND MANUFACTURING METHOD THEREOF [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a holding region and a manufacturing method thereof, and more particularly, to a holding region for holding an object to be polished when polishing the object using the polishing pad and a manufacturing method thereof.

Conventionally, materials (objects to be exposed) such as glass substrates for flat panel displays (FPD), color filters, silicon wafers, and substrates on which indium tin oxide (ITO) film formation has been completed require highly precise flatness, Polishing processing is performed. Generally, in these polishing processes of the objects to be polished, a single-side polishing machine for single-side polishing the object to be polished is used. In this single-side polishing machine, the object to be polished is held on the holding support base, and the polishing cloth is mounted on the polishing base. At the time of polishing, an abrasive liquid containing abrasive grains is supplied, and both platens are rotated while applying pressure to the objects to be polished, whereby the objects to be polished are polished.

Generally, in a polishing process using a single-side polishing machine, in order to suppress scratches and the like of a polished material generated by direct contact with a metal holding plate, the holding plate is provided with a holding pad such as a soft cloth And a retention support for holding the support. Scratching or the like can be avoided by the mounting of the holding pad, but when the adhesion between the holding pad and the object to be polished and the stiction friction are insufficient, that is, when the holding property of the holding pad is insufficient, It is difficult to smoothly polish the object to be polished because lateral displacement of the abrasive occurs. In order to suppress this lateral displacement, there is known a holding support having a template provided with an opening through which an object to be polished can be inserted along the periphery of the holding pad (for example, Patent Document 1 or 2).

Japanese Patent No. 2632738 Japanese Patent Application Laid-Open No. 2014-640

In Patent Document 1, a frame member surrounding the object to be polished is provided to prevent so-called edge sagging due to superimposition of the periphery of the object to be polished and to prevent dropping of the object to be polished, Sized holding pads are disposed, and the holding pads are held by the holding pads. Patent Document 2 discloses a template in which a cutout is put along the inner periphery of a frame member of a holding pad in the form of following a hole of a frame member attached on the holding pad.

In the so-called insert-type retention base as in Patent Document 1, since the holding pads are independently formed and unlike the conventional art, and the frame member is fixed directly to the rigid carrier plate, the cushioning property in the horizontal and vertical directions none. Therefore, when the insert type retainer is used, when the object to be polished is press-fitted to the polishing pad side by the polishing pressure, the polishing pad is strongly pressed to the periphery of the frame material. If the polishing pad and the carrier plate are rotated while the polishing pad is strongly pressed to the periphery of the frame member, the polishing pad or the surface of the frame member may be scratched.

In order to prevent this, as in Patent Document 2, it is considered to provide a holding pad having a slit inside the frame member between the frame member and the surface plate. However, in the holding pad of Patent Document 2, since the frame member is bonded on the skin layer of the holding pad, if a force in the horizontal direction is applied to the frame member during polishing, the frame member tends to peel off from the holding pad There was a problem. Further, in the holding pad of Patent Document 2, since the cutout is formed in the holding pad, the holding pad supporting the frame member is largely fluctuated with sliding movement during polishing, and the frame member is supported If the use time is longer than the cut-out portion, damage to the holding pad is liable to be accumulated and the holding pad is broken, and the object to be polished is likely to be lost and crashed because the cutout is formed in a part of the holding pad there was.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide a holding pawl using holding pads made of foamed polyurethane which prevents edge sagging of a polished object, And also to prevent the peeling of the frame material. The present invention also provides a holding device for a polishing apparatus.

In order to solve the above-described problems, the present invention provides a holding pouch for holding an object to be polished at the time of polishing a subject to be polished, comprising: a holding pad made of foamed polyurethane having a large number of bubbles therein; And a frame member surrounding the holding surface along a periphery of the holding surface of the holding surface, wherein the holding pad has a step formed by cutting the periphery of the holding surface by a predetermined depth, And is fixed to the holding pad so as to be adhered to the holding pad on the horizontal plane of the step portion and the inner circumferential face to face the vertical face of the step portion.

According to the present invention configured as described above, the frame member accommodating the object to be polished can be fixed on the horizontal plane of the stepped portion extending along the periphery of the holding pad. Further, since the object to be polished and the frame member can be held by one holding pad, the inner peripheral surface of the frame member and the holding pad are not bonded and fixed. Therefore, The pressure applied to the object to be polished can be made uniform. As a result, it is possible to prevent the compression deformation of the holding pad from concentrating on the inner peripheral portion of the frame member, so that the edge sagging at the periphery of the object to be polished can be prevented. In addition, by attaching the frame material only on the horizontal plane of the step portion, the holding pad can be interposed between the frame member and the holding support table on which the holding pad is fixed. As a result, the holding pad functions as a cushion of the frame member, allowing the frame member to move in the horizontal and vertical directions at the time of polishing, and as a result, even when the polishing pad rotates in the horizontal direction by the action of the polishing pressure , It is possible to prevent the polishing pad from being strongly pressed against the frame member. Further, the opening of the bubble is made larger than the holding surface by bonding the frame material to the frame material-adhering portion of the holding pad having the bubble therein, so that the adhesive tends to enter the inside of the bubble, It is possible to improve the adhesive force of the frame material by the so-called anchor effect.

In this case, it is preferable that L = 0.25 mm to 1.0 mm, and the depth of the step portion is 40 m to (L-150) m, when the thickness of the holding pad (sheet made of foamed polyurethane) is L .

Further, in the present invention, preferably, a skin layer is formed on the holding surface of the holding pad.

According to the present invention configured as described above, it is possible to reduce scratches and contamination of the object to be polished by foreign matter attached to the holding surface.

In order to solve the above-described problems, the present invention provides a method of manufacturing a holding support for holding an object to be polished at the time of polishing a subject to be polished, comprising the steps of: preparing a holding pad made of foamed polyurethane having a large number of bubbles therein; Forming a stepped portion by cutting a peripheral edge of the holding surface of the holding pad by a predetermined depth to form a stepped portion; forming, along the periphery of the holding surface of the holding pad, an annular or rectangular shape Wherein the frame member is adhered to the holding pad on a horizontal plane of the step portion and the inner circumferential face is fixed to the holding pad so as to face the vertical face of the step portion, .

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to prevent scratches on the polishing pad while preventing edge sagging of the polished object and dropping off the polished object, and also to prevent peeling of the frame material.

1 is a perspective view showing an example of a single side polishing machine to which a holding support according to an embodiment of the present invention is applied.
Fig. 2 is a sectional view of a main portion of the polishing head of the single-side polishing machine of Fig. 1;

Hereinafter, a holding support according to an embodiment of the present invention and a manufacturing method thereof will be described with reference to the drawings. 1 is a perspective view showing an example of a single-side polishing machine to which a retainer is applied.

First, as shown in Fig. 1, the single-side polishing machine 1 is provided with a polishing table 5 on which a polishing pad 3 is fixed. A shaft 7 is provided on the bottom of the polishing platen 5 and the polishing platen 5 is configured to rotate about the axis of the shaft 7. On the polishing pad 3, a polishing head 9 is disposed at a position eccentric from the axis of the shaft 7. Between the polishing head 9 and the polishing pad 3, for example, a silicon wafer W is held as an object to be polished.

Fig. 2 is a sectional view of the main part of the polishing head. Fig. 2 (a), the polishing head is provided with a circular platen 11. On the bottom surface of the platen 11, a holding support 13 according to the embodiment of the present invention Is installed. The holding support 13 has a holding pad 15 formed of foamed polyurethane and a frame member 17 provided on the outer peripheral side of the holding pad 15.

The holding pad 15 has a disk shape and is made of, for example, a polyurethane resin having a modulus of 100% modulus (a value obtained by dividing the load applied when the resin sheet is stretched to twice the length of a non-foamed resin sheet, . In addition, innumerable bubbles 19 are formed in the holding pad 15, and the bubbles 19 improve the cushioning property of the holding pad 15. Further, the surface of the foamed polyurethane resin formed is not subjected to a buff treatment, and therefore, a skin layer formed at the time of film formation remains on the surface thereof.

The frame member 17 is formed by a ring-shaped member having the same outer diameter as that of the holding pad 15 and fixed to the holding pad 15 so that its outer periphery coincides with the outer periphery of the holding pad 15 . The frame member 17 prevents the wafer W from separating from the polishing head 9 and the polishing pad 3 by surrounding the wafer W from the peripheral direction. Therefore, the inner diameter of the frame member 17 is larger than the outer diameter of the wafer W. [ It is preferable that the thickness of the frame material 17 is set so that the depth of the pocket is between -50 mu m and +100 mu m with respect to the thickness of the wafer W, and between -30 mu m and +30 mu m More preferable. The pocket depth is the depth from the polishing surface side of the frame material 17 to the holding surface of the holding pad 15 and is the thickness of the frame material 17 at the portion where the wafer W is held.

A stepped portion 21 for fixing the frame member 17 is formed on the holding pad 15. The step portion 21 is formed so as to surround the holding surface along the periphery of the holding surface in contact with the wafer W. [ The stepped portion 21 is formed by cutting the holding surface of the holding pad 15 having the bubble 19 therein. The horizontal surface and the surface of the vertical surface of the stepped portion 21 are provided with a number of bubbles 19 ) Are exposed. The shape of the step portion 21 is designed so that a part of the frame material 17 protrudes from the holding surface when the frame material 17 is arranged on the step portion 21. [ The inner peripheral surface of the frame member 17 is dimensionally determined so as to be in contact with the vertical surface of the step portion 21 or close to the vertical surface of the step portion 21,

2 (b), since the cushioning property of the holding sheet in the vicinity of the frame member is limited when the side surface of the stepped portion 21 and the inner circumferential surface of the frame member 17 are adhered with an adhesive, It is preferable that the ashes 17 are adhered only to the horizontal surface of the step 21. In the case of performing chamfering of the end portion of the wafer W, polishing of the highly rigid wafer W such as SiC or sapphire, and polishing of the wafer W having a large hole diameter, In the case where the speed is high, the impact when the wafer W and the frame member collide with each other is large, and the frame member is scratched, so that the probability of occurrence of foreign matter increases. In this case, the foreign object is strongly rubbed against the wafer W by the polishing pressure, so that foreign matter adheres to the wafer or scratches may occur due to foreign matter. In order to prevent this, the distance between the inner peripheral surface of the frame member and the side surface of the step portion 21 is preferably 0 mm to 15 mm, more preferably 0.1 mm to 10 mm, and most preferably 0.1 mm to 5 mm. If the interval between the inner peripheral surface of the frame member and the side surface of the step portion 21 is 15 mm or less, the end shape can be improved. On the other hand, if the distance between the inner circumferential surface of the frame member and the side surface of the step portion 21 exceeds 15 mm, the holding pad 15 is not smoothly held and supported by the wafer W, resulting in a decrease in the rate The possibility that the wafer 15 is likely to swing in the frame member and the holding surface can not be kept parallel and the shape of the end portion is deteriorated or the wafer W is detached from the holding pad 15 is increased Which is undesirable.

When fixing the frame material 17 to the holding pad 15, first, a heat-sensitive adhesive sheet of a predetermined thickness, for example, 50 mu m, is bonded on the horizontal surface of the frame material 17. [ Then, the stepped portion 21 and the frame member 17 provided with the heat-sensitive adhesive sheet are arranged on the holding pad 15. Then, when the holding pad 15 and the frame member 17 are heated and pressed to adhere, a part of the adhesive is softened or melted and enters the bubble 19. Then, for example, an adhesive agent capable of forming a layer having a thickness of 30 占 퐉 is contained in the bubble 19, and an adhesive layer having a thickness of about 20 占 퐉 is formed on the horizontal plane. At this time, since the adhesive is adhered on the horizontal plane of the step 21 and not on the vertical plane, the frame member 17 is adhered on the horizontal plane. As a result, the holding pad 15 supports the frame member 17 by an adhesive force in the vertical direction.

The presence of the step 21 also makes it possible to disperse the force applied to the bonding portion due to the step difference with respect to the force in the lateral direction of the wafer W. The depth of the stepped portion is preferably 40 占 퐉 to (L-150) 占 퐉. The depth of the step 21 is preferably at least 40 탆 or more. When the depth of the step 21 is less than 40 mu m, the wafer W acts on the bonding portion between the frame material 17 and the holding sheet at the time of polishing, and the work acts directly on the bonding portion, . Further, the opening diameter on the bonding surface of the holding pad is small, so that the permeation of the adhesive is reduced, and the strength of the bonding surface of the frame member 17 is lowered. In addition, by setting the step 21 to 40 m or more, the displacement of the frame member 17 in the horizontal direction can be interfered at the stepped portion of the holding pad, so that the damage of the bonded portion can be further reduced. When the level difference 21 is larger than (L-150) 占 퐉, the strength of the frame member 17 to the holding pad is improved, while the sinking of the frame member 17 to the holding pad is small, There is a possibility of causing damage to the apparatus. Further, in order to secure the pocket depth, it is necessary to increase the thickness of the frame material 17, and the cost of the frame material increases, which is not preferable. The cushioning property of the frame material can be maintained by setting the thickness of the holding pad 15 between the frame material 17 and the circular platen 11 (holding platen) to be 150 mu m or more, more preferably 200 mu m or more, It is possible to further reduce the damage to the furnace.

As described above, according to the embodiment of the present invention, the frame member 17 for preventing the wafer W from falling out is fixed on the horizontal plane of the step portion 21 extending along the periphery of the holding pad 15 can do. Since the wafer W and the frame member 17 are held by the single holding pad 15 and the inner peripheral surface of the frame member 17 and the holding pad 15 are not bonded and fixed, It is possible to disperse the polishing stress immediately under the object to be polished and under the frame material 17 to uniform the pressure applied to the object to be polished. Thus, it is possible to effectively prevent edge sagging at the periphery of the wafer W.

Between the frame material 17 and the base 11 on which the holding pad 15 is fixed by bonding the frame material 17 on the horizontal surface of the step 21, ) Can be intervened. Thereby, the holding pad 15 functions as a cushion of the frame member 17, and it is possible to allow the frame member 17 to move in the vertical direction at the time of polishing, and as a result, Even when the polishing pad 3 rotates in the horizontal direction, it is possible to prevent the polishing pad 3 from being strongly pressed against the frame member 17 and damaging the polishing pad 3. The frame member 17 is adhered to the horizontal surface of the step portion 21 so that the adhesion surface of the frame member 17 and the holding pad 15 and the holding surface of the holding pad 15 are held Can be shifted in the thickness direction of the support pad (15). Thereby, it is possible to prevent the wafer W from applying stress to the adhesive layer during polishing, and to prevent peeling of the frame material 17.

The holding pads 15 having the bubbles 19 therein are cut to expose the bubbles 19 and the frame material 17 is adhered thereon so that the adhesive enters the inside of the bubbles 19, The adhesive strength of the frame member 17 to the holding pad 15 can be further improved.

In the present embodiment, a description has been given of the case where the skin layer is formed on the holding surface for holding the object to be polished, but the present invention is not limited to this. From the viewpoint of controlling the adsorption holding force of the abrasive to be polished, the surface of the skin layer may be opened by buffing. The surface of the skin layer formed by the buffing treatment can make the holding pad of the frame reattachment portion larger, and the peeling strength can be further increased. In addition, by providing the step 21, the change in elasticity is reduced even on the holding surface of the peripheral portion of the frame member as compared with the holding member having no step, so that it is possible to contribute to reduction of end sagging, The polishing can be performed stably in the long term. However, since grinding chips or abrasive chips may enter the holding surface opening and stick to the object to be polished, by making the holding surface a skin layer, the rise of the holding pad can be improved, It is possible to reduce the adherence and scratching of the foreign object to the object.

A flexible plastic sheet member such as PET may be adhered to the back side of the holding pad 15 as the structure of the holding support 13, Is easy to handle. Further, since the holding support strip 13 is provided on the holding support table 11, a double-sided tape having a release sheet may be provided on the holding support table 11 side. With this configuration, mounting to the holding support base 11 is facilitated.

<Examples>

Hereinafter, an embodiment of the holding support manufactured according to the present embodiment will be described, but the present invention is not limited to the embodiments.

(Example 1)

The film was formed to have a thickness of 0.40 mm by a wet film forming method to prepare a foamed polyurethane sheet. A PET film as a supporting substrate was bonded to the back side of the foamed polyurethane sheet (the side opposite to the holding surface) via an adhesive. Then, a double-sided tape having one side releasing paper for holding and supporting platen bonding was adhered to the opposite side of the PET film to produce a holding sheet. Thereafter, the retaining sheet was cut into a circle of 290 mm in diameter, and a stepped portion having an outer circumference of 270.0 mm, an inner circumference of 200.8 mm (width 34.6 mm) and a depth of 100 μm was machined on the outer periphery of the holding surface of the foamed polyurethane sheet by an NC router Thereby forming a stepped portion. On the other hand, a glass epoxy plate having a thickness of 0.87 mm was cut into a ring shape having an outer diameter of 260 mm and an inner diameter of 201 mm (width 29.5 mm), and chamfering was performed on one side of the outer peripheral portion. Subsequently, a heat-sensitive adhesive film having a square length of 300 mm and a thickness of 50 占 퐉, which is longitudinal and transversal to the side not chamfered, was bonded and bonded. Thereafter, an extra portion (outer side and inner side than the inner diameter of 201 mm?) Having a diameter of 260 mm?, Which is hollowed out from the ring-shaped frame material, was cut out to complete the frame member. The adhesive film side of the frame material joining the adhesive film to the stepped portion of the holding sheet on which the stepped portion is formed is aligned and laminated and subjected to hot press processing from the upper surface of the frame material to form a foamed polyurethane sheet The heat-sensitive adhesive was melted and adhered. A portion of the extra holding sheet (260 mm or more in outer diameter) was cut off and the product was completed. The pocket depth (height at which the frame member protrudes from the holding surface) was measured to be 0.77 mm.

(Example 2)

The skin layer side of the foamed polyurethane sheet was buffed by using a sandpaper having a buff number of # 180 at a buffer treatment amount of 0.16 mm and a holding surface was opened to form a foamed polyurethane foam having a thickness of 0.40 mm A sheet was prepared in the same manner as in Example 1 to prepare a holding support having a stepped portion. The pocket depth was measured to be 0.77 mm.

(Example 3)

A step portion having an outer periphery of 270.0 mm, an inner periphery of 181.0 mm (width of 44.5 mm) and a depth of 100 μm was formed on the outer periphery of the holding surface of the foamed polyurethane sheet, and a step was formed such that the interval between the inner peripheral surface of the frame member and the side surface of the step portion was 10 mm A retaining support having a stepped portion was produced in the same manner as in Example 1. The pocket depth was measured to be 0.77 mm.

(Comparative Example 1)

A 0.40 mm thick foamed polyurethane sheet having the skin layer of Example 1 was used and the retainer was manufactured in the same manner as in Example 1 except that the stepped portion was not formed and the thickness of the glass epoxy plate was 0.72 mm Respectively. The pocket depth was measured to be 0.77 mm.

(Comparative Example 2)

A foamed polyurethane sheet having a thickness of 0.40 mm and a surface of which was buffed in Example 2 was used, and in the same manner as in Example 2 except that no step was formed and the thickness of the glass epoxy plate was 0.77 mm, . The pocket depth was measured to be 0.77 mm.

(Comparative Example 3)

A holding support was produced in the same manner as in Example 1 except that the depth of the stepped portion was 30 占 퐉 and the thickness of the glass epoxy plate was 0.81 mm. The pocket depth was measured to be 0.77 mm.

(Comparative Example 4)

A holding support was produced in the same manner as in Example 1 except that the depth of the stepped portion was set to 300 탆 and the thickness of the glass epoxy plate was set to 1.06 mm. The pocket depth was measured to be 0.77 mm.

(Comparative Example 5)

A stepped portion having an outer circumference of 270.0 mm, an inner circumference of 157.0 mm (width 56.5 mm) and a depth of 100 μm was formed on the outer surface of the holding surface of the foamed polyurethane sheet, and a step was formed such that the interval between the inner surface of the frame and the side surface of the stepped portion was 22 mm A retaining support having a stepped portion was produced in the same manner as in Example 1. The pocket depth was measured to be 0.77 mm.

(Polishing performance evaluation)

Then, polishing of the silicon wafers using the holding supports of each of the examples and the comparative examples was carried out under the following conditions, and the holding performance was evaluated by the polishing rate, end sag and peel strength. The polishing rate was calculated by the difference in weight before and after polishing. The end sag occurs when the peripheral portion of the object to be polished is excessively polished than the central portion, and is one of the measurement items for evaluating the flatness. As a measuring method, for example, a two-dimensional profile image is obtained in a range of from a position of 0.3 mm from the outer peripheral end toward the center in the radial direction by 2 mm with an optical surface roughness meter. When the radial direction is taken as the X axis and the thickness direction is taken as the Y axis on the obtained two-dimensional profile, the leveling correction is made so that the value of the Y axis at the coordinate position of X = 0.5 mm and X = Respectively. The PV value between X = 0.5 and 1.5 mm on the two-dimensional profile at this time is expressed as a relative value. A surface roughness tester (New View 5022, manufactured by Zygo Co., Ltd.) was used to measure the end sag. The peel strength was measured by peeling strength between the frame material and the holding sheet in a 180 degree peel test in the holding pockets of each of the examples and the comparative examples. The peel strength measurement can indirectly estimate the lifetime of the frame by peeling off the frame, the frame member and the holding sheet are hardly peeled off, and the longer the peel strength is, the better the life of the retention support can be. The polishing results and the peel strength measurement results are shown by the ratios of Comparative Example 1 to 1.0. The measurement results are shown in Table 1 below.

(Polishing condition)

Polisher used: manufactured by Fujiko City, MCP-150X

Polishing pad: manufactured by Fuji Bow Ehime Co., Ltd., POLYPAS CM4301

Number of revolutions: (Platen) 100r / m, (Top ring) 75r / m

Polishing pressure: 330 g / cm &lt;

Swing width: 10 mm (200 mm from the swing center value)

Shaking motion: 1mm / min

Abrasive: manufactured by Nalco, product number 2350 (using a mixed solution of 2350 stock solution: water = 1: 9)

Objects to be polished: 8 inch silicon wafers (thickness 780 탆)

Polishing time: 20 minutes

[Evaluation results]

In Example 1, the influence of the step on the end portion of the work was reduced and the end sag was reduced by half. Since the contact between the frame material and the wafer was suppressed, the peeling was improved and the peeling strength was improved to 1.7 times that of Comparative Example 1 .

In Example 2, the hole diameter in the stepped portion was larger than that in Example 1, and the amount of adhesive was increased, so that the peel strength was improved by 1.8 times as compared with Comparative Example 1. On the other hand, since the holding surface is open, there is the influence of the grinding chip or the like and the attachment of the particles, and the start-up time is twice as long as that in the embodiment 1.

In Example 3, since the width of the stepped portion was larger than that in Example 1, and the outermost periphery of the wafer was on the stepped portion and was not in contact with the holding pad, end sagging of the wafer outermost peripheral portion was reduced.

In Comparative Example 1, the compression deformation of the holding pad is concentrated on the inner periphery of the frame member due to the absence of the stepped portion, and the end sagging is two times worse than in the embodiment, and the peeling strength is lower than in Example 1, .

In Comparative Example 2, since there was no step difference, the compression deformation of the holding pad concentrated on the inner periphery of the frame member, and the end sag was twice as bad as in the embodiment. Since the foamed polyurethane sheet was provided, the bonding strength was the same as in Example 1, but it is considered that the wafer is liable to be peeled off due to the direct action of the wafer on the bonding portion between the frame material and the foamed polyurethane sheet. As in the case of Example 2, there was particle adherence, and the increase was twice as long as in Example 1 because the holding surface was open.

In Comparative Example 3, since the depth of the stepped portion was insufficient, the buffer thickness was small and the pore diameter was small, the permeation of the pressure-sensitive adhesive deteriorated, and the peel strength was lower than in Examples 1 and 2. In addition, the end sag was lower than that of the examples.

In Comparative Example 4, the depth of the stepped portion was large and the peel strength was the same as in Examples 1 and 2. However, the thickness of the foamed polyurethane sheet under the frame material was not sufficient and during the grinding process, This is because the abrasion pressure on the work is reduced by the amount of sitting less, or the edge shape is excellent, but the rate is lowered. Further, the contact between the polishing pad and the frame member is strengthened, and it is presumed that the peeling of the frame material and the damage of the polishing pad will be accelerated.

In Comparative Example 5, since the interval between the inner circumferential surface of the frame material and the side surface of the stepped portion was excessively wide, the rate deteriorated and the end portion shape deteriorated because of the insufficient holding force of the holding pad.

13:
15: Holding pad
17: frame member
19: Bubble
21:

Claims (4)

A holding support for holding an object to be polished when polishing the object to be polished,
A holding pad made of foamed polyurethane having a plurality of bubbles therein,
And a frame member surrounding the holding surface along the periphery of the holding surface of the holding pad,
Wherein the holding pad has a stepped portion formed by cutting a peripheral edge of the holding surface by a predetermined depth,
Wherein the frame member is adhered to the holding pad on a horizontal plane of the step portion, and the inner circumferential surface is fixed to the holding pad so as to face the vertical face of the step portion. 2. The retainer according to claim 1, wherein the thickness L of the holding pad is 0.25 to 1.0 mm and the depth of the step is 40 to (L-150) 占 퐉. 3. The retainer according to claim 1 or 2, wherein the holding surface of the holding pad is formed of a skin layer. A method for manufacturing a holding support member for holding an object to be polished at the time of polishing the object to be polished,
Preparing a holding pad made of foamed polyurethane having a plurality of bubbles therein,
A step of cutting the peripheral edge of the holding surface of the holding pad by a predetermined depth to form a stepped portion,
And a step of fixing the frame member surrounding the holding surface along the periphery of the holding surface of the holding pad with an adhesive,
Wherein the frame member is adhered to the holding pad on a horizontal plane of the step portion and the inner circumferential surface is fixed to the holding pad so as to face the vertical face of the step portion.

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