JP2023133815A - polishing body - Google Patents

Abstract

To provide a polishing body which can suppress deterioration even if it polishes using a strongly acidic polishing liquid, can be repeatedly detached from/attached to a surface plate, and can contribute to reduction of polishing cost of a polished object.SOLUTION: A polishing machine includes a surface plate 13 rotating around a shaft center O1, and a carrier 22 for holding a wafer 20 as a polished object so as to be relatively rotatable with respect to the surface plate 13. A polishing body 1 is fixed to a fixed surface 13a of the surface plate 13. The polishing body 1 has a polishing pad 3, an adhesive layer 5, and a cushion layer 7. The polishing pad 3 has a base material 33 having a plurality of pores 37, and polishing particles 35 held in the base material 33 or the pores 37. The base material 33 is made of polyvinylidene fluoride. The cushion layer 7 is composed of an elastically deformable silicone-based porous body, and is adsorbed to the fixed surface 13a in a detachable/attachable manner. The adhesive layer 5 contains a silicone-based adhesive component.SELECTED DRAWING: Figure 1

Description

The present invention relates to an abrasive body.

Polishing machines equipped with a surface plate and a carrier are known. The surface plate has a fixed surface extending in a direction perpendicular to the axis, and is rotated around the axis. The carrier holds a flat object to be polished relative to the surface plate so as to be rotatable relative to the surface plate.

When polishing a wafer of silicon carbide (SiC) or gallium nitride (GaN) as an object to be polished using this polishing machine, the polishing body is fixed to the fixed surface of the surface plate, and the wafer is mounted on the carrier relative to the surface plate. Rotatably held. Then, the wafer is rotated relative to the surface plate while the polishing pad of the polishing body and the wafer are brought into contact with each other with a predetermined surface pressure in the presence of the polishing liquid. If this polishing liquid contains chemical components such as acid or alkali, the wafer surface is polished by CMP (Chemical Mechanical Polishing).

The polishing body used in CMP polishing is desirably made of a material with excellent chemical resistance. Patent Document 1 discloses a polishing body in which a polishing pad is difficult to peel off from a double-sided adhesive sheet even when an oxidizing agent aqueous solution having a pH of about 4.5 to 5.5 is used as a polishing liquid in polishing by CMP. In this polishing body, a silicone adhesive is used as the adhesive for the double-sided adhesive sheet that is adhered to the polishing pad.

In addition, the polishing body disclosed in Patent Document 1 has a cushion layer made of polyurethane foam between the polishing pad and the surface plate, and the flexible cushion layer improves the processing flatness of the polished surface of the wafer. I am trying to do. This cushion layer is bonded to the polishing pad using the silicone adhesive described above, and is also bonded to the surface plate using an acrylic adhesive.

Japanese Patent Application Publication No. 2019-145689

However, particularly in polishing processes where the object to be polished is a difficult-to-process material such as SiC or GaN, a strongly acidic polishing liquid with a pH of 3 or less is often used. In this case, in the polishing body disclosed in Patent Document 1, its constituent components such as a polishing pad and a cushion layer may deteriorate, resulting in a shortened lifespan.

Further, the polishing body disclosed in Patent Document 1 is fixed to the surface plate with an adhesive. In this case, if the polishing body is peeled off from the surface plate when replacing the polishing body, a decrease in the adhesive ability of the adhesive is unavoidable. For this reason, it is difficult to reuse the polishing body that has separated from the surface plate, and there are many cases in which expensive polishing bodies are discarded after a short period of time. In actual polishing processes at processing sites, etc., the number of polishers is limited, and the polishing bodies used must be selected for each material of the object to be polished, and the polishing bodies must be replaced frequently. If the polishing body, which is expensive and needs to be replaced frequently, cannot be reused, the cost of polishing wafers will increase.

The present invention has been made in view of the above-mentioned conventional circumstances, and is capable of suppressing deterioration even when polishing using a strongly acidic polishing liquid, and can be repeatedly attached to and detached from a surface plate. The problem to be solved is to provide a polishing body that can contribute to reducing the cost of polishing an object to be polished.

The polishing body of the present invention has a fixed surface extending in a direction perpendicular to the axis, and a surface plate that is rotated around the axis, and a flat object to be polished can be rotated relative to the surface plate. Used in polishing machines equipped with a carrier that holds
A polishing body fixed to the fixed surface and polishing the object to be polished under a predetermined surface pressure in the presence of a polishing liquid,
A polishing pad made of polyvinylidene fluoride and having a base material in which a plurality of pores are formed, and abrasive particles held within the base material or within the pores;
a cushion layer made of an elastically deformable silicone-based porous body and removably adsorbed to the fixed surface;
It is characterized by comprising an adhesive layer containing a silicone-based adhesive component, interposed between the polishing pad and the cushion layer and bonding the polishing pad and the cushion layer.

According to tests conducted by the inventors, since the base material of the polishing pad is made of polyvinylidene fluoride, the polishing pad is unlikely to deteriorate even when polishing is performed using a strongly acidic polishing liquid. Moreover, since the cushion layer is silicone-based, the cushion layer is unlikely to deteriorate even when polishing is performed using a strongly acidic polishing liquid. Furthermore, since the adhesive component of the adhesive layer is silicone-based, the adhesive layer is unlikely to deteriorate even when polishing is performed using a strongly acidic polishing liquid.

Further, the polishing body of the present invention can be repeatedly attached to and detached from the surface plate due to the suction effect of the cushion layer, which does not easily deteriorate even when polishing is performed using a strongly acidic polishing liquid.

Therefore, the polishing body of the present invention can suppress deterioration even when polishing using a strongly acidic polishing liquid, and can be repeatedly attached to and detached from the surface plate, thereby reducing the cost of polishing the object to be polished. can contribute to

The polishing body of the present invention can suppress deterioration even when polishing using a strongly acidic polishing liquid, and can be repeatedly attached to and detached from the surface plate, which in turn contributes to reducing the cost of polishing the object to be polished. It is possible.

FIG. 1 is an enlarged schematic cross-sectional view of a part of the polishing body of Example 1. FIG. 2 is an enlarged schematic cross-sectional view of a part of the polishing pad constituting the polishing body of Example 1. FIG. 3 is a partially enlarged schematic sectional view of the polishing body of Example 1 fixed to a surface plate. FIG. 4 is a schematic cross-sectional view of the wafer polishing machine.

The polishing body of the present invention is used in a polishing machine equipped with a surface plate and a carrier. The surface plate has a fixed surface extending in a direction perpendicular to the axis, and is rotated around the axis. The carrier holds a flat object to be polished relative to the surface plate so as to be rotatable relative to the surface plate.

The polishing body of the present invention is fixed to a fixed surface of a surface plate, and polishes an object to be polished under a predetermined surface pressure in the presence of a polishing liquid. The polishing liquid may be pure water, oil-based, or containing acidic or alkaline chemicals. The polishing body of the present invention can suppress deterioration even when using a strongly acidic polishing liquid having a pH of 3 or less or a pH of 1 or less.

A semiconductor wafer can be used as the object to be polished by the polishing body of the present invention. The polishing body of the present invention can be suitably used particularly when a difficult-to-process material such as silicon carbide (SiC), gallium nitride (GaN), or aluminum nitride (AlN) is to be polished.

A polishing machine to which the polishing body of the present invention is attached can be suitably used in a lapping process in which semiconductor wafers are rough-processed or subsequently finished. The lapping process may be either single-sided lapping, in which only one side of the semiconductor wafer as the object to be polished is lapped, or double-sided lapping, in which both sides of the semiconductor wafer are simultaneously lapped by a pair of polishing bodies.

The polishing body of the present invention includes a polishing pad, an adhesive layer, and a cushion layer. A cushion layer, an adhesive layer, and a polishing pad are laminated in this order. That is, the adhesive layer is interposed between the polishing pad and the cushion layer and adheres to the polishing pad and the cushion layer.

A polishing pad has a base material and polishing particles. The base material is made of polyvinylidene fluoride (PVDF). The base material made of polyvinylidene fluoride does not easily deteriorate even when using a strongly acidic polishing liquid with a pH of 1 or less. Moreover, a plurality of pores are formed in the base material. The abrasive particles are retained within the matrix or within the pores.

The polishing pad preferably has a pad-side impregnated layer impregnated with an adhesive component at the interface with the adhesive layer in the polishing pad. The pad-side impregnated layer can improve bonding between the polishing pad and the adhesive layer. The polishing pad preferably has a continuous pore structure, and it is particularly preferable that the polishing pad has a continuous pore structure in a region including the interface with the adhesive layer. That is, it is preferable that continuous pores are opened at the interface with the adhesive layer in the polishing pad. If continuous pores are opened at the interface with the adhesive layer in the polishing pad, the adhesive component is likely to be impregnated through the openings. Therefore, a pad-side impregnated layer is likely to be formed at the interface with the adhesive layer in the polishing pad.

As the material of the polishing particles, silica, ceria, alumina, zirconia, titania, diamond, manganese oxide, barium carbonate, chromium oxide, iron oxide, etc. can be used. These may be used alone or in combination of two or more.

The cushion layer is made of an elastically deformable silicone-based porous body. A silicone-based cushion layer does not easily deteriorate even when using a strongly acidic polishing liquid with a pH of 1 or less. The cushion layer is preferably made of silicone rubber foam.

Due to the adsorption action of the cushion layer made of a porous material, the cushion layer is repeatedly adsorbed to and detachable from the fixed surface of the surface plate. Although the pores in the cushion layer may include independent pores, from the viewpoint of improving the adsorption effect of the cushion layer, the continuous porosity in the cushion layer is preferably about 90% or more.

The cushion layer preferably has a cushion-side impregnated layer impregnated with an adhesive component at the interface with the adhesive layer. The cushion-side impregnated layer can improve bonding between the cushion layer and the adhesive layer. The cushion layer preferably has a continuous pore structure in a region of the cushion layer that includes the interface with the adhesive layer. That is, it is preferable that continuous pores are opened at the interface between the cushion layer and the adhesive layer. If continuous pores are opened at the interface between the cushion layer and the adhesive layer, the adhesive component can easily be impregnated through the openings. Therefore, a cushion-side impregnated layer is likely to be formed at the interface between the cushion layer and the adhesive layer.

Preferably, the polishing pad has a pad-side impregnated layer and the cushion layer has a cushion-side impregnated layer. In this case, the pad-side impregnated layer enhances the bondability between the polishing pad and the adhesive layer, and the cushion-side impregnated layer enhances the bondability between the cushion layer and the adhesive layer. Therefore, even when polishing is performed using a strongly acidic polishing liquid, the bonding integrity of the polishing pad, adhesive layer, and cushion layer is less likely to deteriorate.

The thickness of the cushion layer is preferably 100 μm to 500 μm. In this case, good adhesion to the fixed surface of the surface plate can be ensured. In addition, by elastically deforming the flexible cushion layer, the function of the cushion layer can be more effectively exerted, which is to improve the processing flatness of the surface to be polished and to suppress the occurrence of micro scratches on the surface to be polished. becomes possible.

The flexibility and adhesion to the surface plate of the cushion layer can be adjusted by appropriately setting the expansion ratio, continuous porosity, hardness, etc.

The adhesive layer contains a silicone-based adhesive component. A silicone adhesive containing a silicone adhesive component does not easily deteriorate even when a strongly acidic polishing liquid with a pH of 1 or less is used.

During the manufacturing process of the polishing body, warping may occur due to differences in the amount of expansion and contraction between the layers. The warpage in the polishing body of the present invention is preferably 30 mm or less. An abrasive body with a warp of more than 30 mm may not be able to be attached to the fixed surface of the surface plate. The warpage of the polishing body can be determined by placing the polishing body with the concave surface facing up on a flat measuring table and measuring the height of the most warped edge from the measuring table.

Each component in the polishing body of the present invention does not easily deteriorate even when using a strongly acidic polishing liquid with a pH of 1 or less. Furthermore, the suction effect of the cushion layer allows it to be repeatedly attached to and detached from the surface plate. Therefore, the polishing body of the present invention can contribute to reducing the cost of polishing an object to be polished.

(Example)
Examples embodying the present invention will be described below, as well as Comparative Examples 1 to 6 for comparison. In Examples and Comparative Examples 1 to 6, the type of resin used for the base material of the polishing pad, the type of adhesive used for the adhesive layer, the type of material used for the cushion layer, the presence or absence of a second adhesive layer, and its type. Table 1 shows the amount of warpage of the polishing body.

As shown in FIG. 1, the polishing body 1 of the example includes a polishing pad 3, an adhesive layer 5, a cushion layer 7, and a release paper 9. As shown in FIG. 3, the polishing body 1 is pasted on the fixing surface 13a of the surface plate 13 after the release paper 9 is peeled off.

The polishing pad 3 has a polishing surface 3a and a bonded surface 3b facing opposite to the polishing surface 3a and spaced apart from the polishing surface 3a in the thickness direction. An adhesive layer 5 is bonded to the surface 3b of the polishing pad 3 to be bonded. The polishing pad 3 has a pad-side impregnated layer 31 impregnated with the adhesive component of the adhesive layer 5 at the interface with the adhesive layer 5 .

As shown in FIG. 2, the polishing pad 3 includes a base material 33 and polishing particles 35. The base material 33 is made of polyvinylidene fluoride (PVDF). A plurality of pores 37 are formed in the base material 33 . Polishing pad 3 has a continuous pore structure. Specifically, a large number of continuous pores are opened at the interface between the polishing pad 3 and the adhesive layer 5 . By impregnating the adhesive component through this opening, a pad-side impregnated layer 31 is formed at the interface with the adhesive layer 5 in the polishing pad 3 .

The polishing particles 35 are made of silica particles with an average particle size of 0.3 μm.

The polishing pad 3 has a disc shape with a diameter of 300 mm and a thickness of 1.5 mm.

The cushion layer 7 is made of silicone rubber foam. The cushion layer 7 has a disk shape with a diameter of 300 mm and a thickness of 300 μm.

The cushion layer 7 has a suction surface 7a and a bonded surface 7b facing opposite to the suction surface 7a and spaced apart from the suction surface 7a in the thickness direction. The adhesive layer 5 is adhered to the adhesive surface 7b of the cushion layer 7. The cushion layer 7 has a cushion-side impregnated layer 71 impregnated with the adhesive component of the adhesive layer 5 at the interface with the adhesive layer 5 .

The cushion layer 7 has a continuous porosity of about 90% or more, and has a continuous pore structure in a region including the interface with the adhesive layer 5. That is, continuous pores are opened at the interface between the cushion layer 7 and the adhesive layer 5. By impregnating the adhesive component through this opening, a cushion-side impregnated layer 71 is formed at the interface between the cushion layer 7 and the adhesive layer 5 .

The adhesive constituting the adhesive layer 5 is a commercially available silicone adhesive.

The release paper 9 is made of PET film. The release paper 9 is peeled off from the suction surface 7a of the cushion layer 7 when the polishing body 1 is attached to the surface plate 13. By adhering the release paper 9 to the suction surface 7a until just before pasting, the suction surface 7a can be protected, and the abrasive body 1 can be handled while avoiding the inconvenience of the suction surface 7a adhering to other members. can improve sex.

The polishing pad 3 in this polishing body 1 was manufactured as follows.

<Preparation process>
Binder resin: PVDF, abrasive particles: silica particles, and solvent: N-methyl-2-pyrrolidone were prepared.

<Mixing process>
A paste was obtained by mixing 15 parts by mass of binder resin, 15 parts by mass of abrasive particles, and 70 parts by mass of solvent.

<Molding process>
Using the obtained paste, a sheet-like molded body was obtained using a T-die.

<Pore formation process, drying process>
The obtained molded body was immersed in water, and the solvent in the molded body was replaced with water to form a large number of continuous pores. After a predetermined period of time had elapsed, the molded body was taken out of the water and dried to obtain an intermediate body.

<Grinding process>
The surface of the obtained intermediate was ground to a predetermined thickness to obtain a polishing pad 3 having a polishing surface 3a.

<Adhesion process>
A silicone adhesive is applied to the adhesive surface 3b of the obtained polishing pad 3, and a similar silicone adhesive is also applied to the adhesive surface 7b of the cushion layer 7 cut into a predetermined shape. , 7b were crimped together. As a result, the polishing pad 3 and the cushion layer 7 were bonded together by the adhesive layer 5. Finally, the release paper 9 was adsorbed to the adsorption surface 7a of the cushion layer 7 to complete the polishing body 1.

The resulting polishing body 1 had a warpage of 20 mm.

The thus obtained polishing body 1 is used as a fixed abrasive grindstone tool by attaching the suction surface 7a of the cushion layer 7 from which the release paper 9 has been removed to the fixed surface 13a of the surface plate 13 by suction. .

(Comparative example 1)
The structure is the same as that of the example except that the warpage is 40 mm.

The polishing body of Comparative Example 1 could not be attached to the fixed surface 13a of the surface plate 13 because the warpage was too large.

(Comparative example 2)
Polyether sulfone (PES) was used as the resin for the base material 33 in the polishing pad 3.

The other configurations are the same as in the first embodiment.

(Comparative example 3)
A silicone adhesive was applied to the adhesive surface 3b of the polishing pad 3 obtained in the same manner as in the example, and the polishing pad 3 was directly attached to the fixed surface 13a of the surface plate 13. That is, the polishing body of Comparative Example 3 does not have the cushion layer 7.

(Comparative example 4)
As the cushion layer 7, foamed polyurethane having an open pore structure was used. Then, the cushion layer 7 made of polyurethane foam was attached to the fixing surface 13a of the surface plate 13 using a second contact layer made of an acrylic adhesive.

The other configurations are the same as those in the embodiment.

(Comparative example 5)
An acrylic adhesive was used as the adhesive for the adhesive layer 5.

The other configurations are the same as those in the embodiment.

(Comparative example 6)
An acrylic adhesive was used as the adhesive for the adhesive layer 5. Further, as the cushion layer 7, foamed polyurethane having an open pore structure was used. Then, the cushion layer 7 made of polyurethane foam was attached to the fixing surface 13a of the surface plate 13 using a second contact layer made of an acrylic adhesive.

The other configurations are the same as those in the embodiment.

(Evaluation of lifespan of polishing body)
The lifespan of the polishing bodies 1 of Example and the polishing bodies of Comparative Examples 1 to 6 was evaluated.

Each polishing body was cut into a square of 20 mm x 20 mm to prepare each test piece, and this test piece was immersed in a potassium permanganate (KMnO ₄ ) aqueous solution adjusted to pH 1. Then, the degree of deterioration of each component was visually observed after 50 hours had passed since the start of immersion and after 100 hours had passed since the start of immersion.

The lifespan was evaluated as × for completely deteriorated, △ for partially deteriorated, and ○ for no deterioration. The results are shown in Table 2.

The polishing body of the example in which polyvinylidene fluoride was used as the resin for the base material 33, a silicone adhesive was used for the adhesive layer 5, and silicone rubber was used for the cushion layer 7, even after 100 hours had passed from the start of immersion. , all constructs were not degraded.

The polishing pad of Comparative Example 2 in which polyether sulfone was used as the resin for the base material 33 had completely deteriorated after 50 hours.

The cushion layers of Comparative Examples 4 and 6 using polyurethane foam partially deteriorated after 50 hours and completely deteriorated after 100 hours.

Furthermore, the second contact layer made of the acrylic adhesive in the polishing bodies of Comparative Examples 4 and 6 had completely deteriorated after 50 hours.

The adhesive layers 5 of Comparative Examples 5 and 6 using acrylic adhesives partially deteriorated after 50 hours and completely deteriorated after 100 hours.

(Evaluation of repeated attachment/detachability to surface plate)
The polishing bodies 1 of Example and the polishing bodies of Comparative Examples 2 to 6 were evaluated for their ability to be repeatedly attached to and removed from the surface plate 13.

This evaluation shows that when the polishing bodies 1 of Example and each of Comparative Examples 2 to 6 are peeled off from the fixed surface 13a of the surface plate 13 and then affixed to the fixed surface 13a again, If there is no attachment defect), it is marked as 〇, and if there is any lifting of the polishing body, it is marked as ×. The results are shown in Table 2.

The polishing body 1 of the example, which was attached to the surface plate 13 due to the adsorption properties of the cushion layer 7 made of silicone rubber foam, had no attachment defects and could be repeatedly attached to and detached from the surface plate.

The polishing body of Comparative Example 3, which did not have a cushion layer and had the polishing pad 3 adhered to the surface plate 13 through the adhesive layer 5, had poor adhesion.

The polishing bodies of Comparative Examples 4 and 6, in which a cushion layer made of polyurethane foam was attached to the surface plate 13 using an acrylic adhesive, had poor attachment.

(Processing test)
A wafer polishing machine (Engis EJW-380) shown in FIG. A processing test was carried out for lapping, which involves polishing.

This wafer polishing machine includes a plurality of carriers 22, a surface plate 13, a drive device 24, and a polishing liquid supply device 26. Although only a single carrier 22 is shown in FIG. 4, the wafer polisher may have multiple carriers 22. Each carrier 22 has a horizontal disk shape. A wafer fixing surface 22a is recessed in the lower surface of each carrier 22, and the wafer 20 is fixed to the wafer fixing surface 22a. A carrier rotating shaft 28 is vertically protruded from the upper surface of each carrier 22 . The surface to be polished 20a, which is the Si surface of each wafer 20, faces downward.

The surface plate 13 has a horizontal disk shape that encloses all the carriers 22. A surface plate rotating shaft 30 is vertically protruded from the lower surface of the surface plate 13. The upper surface of the surface plate 13 is a fixed surface 13a. The polishing body 1 of Example 1 and the polishing bodies of Comparative Examples 2 to 6 are attached to the fixed surface 13a so as to face each wafer 20.

The drive device 24 includes a main drive device 24a, a sub drive device 24b, and a pressure device 24c. The main drive device 24a rotates the surface plate rotating shaft 30 around the first axis O1 at a predetermined speed. The sub-drive device 24b rotates each carrier rotating shaft 28 around the second axis O2 at a predetermined speed. The pressure device 24c applies pressure to each carrier rotating shaft 28 and the sub-drive device 24b toward the surface plate 13 with a predetermined load.

The polishing liquid supply device 26 is provided above the surface plate 13. The polishing liquid supply device 26 interposes a polishing liquid 26a between each wafer 20 and the polishing body 1. The polishing liquid 26a consists of an aqueous potassium permanganate solution adjusted to pH 1 and does not contain polishing particles.

Using this wafer polisher, a processing test was conducted in which a wafer 20 was polished under the following conditions.
Wafer 20 as object to be polished: 4H-SiC single crystal with a diameter of 4 inches Flow rate of polishing liquid 26a: 10 mL/min Load: 30 kPa
Rotation speed of surface plate 13: 60 rpm
Rotation speed of carrier 22: 60 rpm
Processing time: 60 minutes

(Evaluation of processed flatness of polished surface)
The processed flatness of the polished surface 20a of the wafer 20 after the above processing test was evaluated.

In this evaluation, the amount of processing was measured at five points within the surface of the wafer, including the center point within the wafer surface and four points on the outer circumference of the wafer, on the surface to be polished 20a after the processing test. Then, when the maximum machining amount is Rmax and the minimum machining amount is Rmin, if the difference ΔR between the maximum machining amount and the minimum machining amount (ΔR = Rmax - Rmin) is ΔR>3μm, it is marked as ×, and when ΔR≦3μm, it is marked as ×. If so, mark it as 〇. The results are shown in Table 2.

The polishing bodies 1 of Examples having the cushion layer 7 made of silicone rubber foam all had a ΔR value of 3 μm or less, and had good processing flatness.

The polishing body of Comparative Example 3, which did not have a cushion layer, had poor processing flatness.

Although the present invention has been described above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be applied with appropriate modifications without departing from the spirit thereof.

INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing apparatus of a semiconductor device.

1... Polishing body 3... Polishing pad 5... Adhesive layer 7... Cushion layer 31... Pad side impregnated layer 33... Base material 35... Abrasive particles 37... Pores 71... Cushion side impregnated layer

Claims (3)

A surface plate having a fixed surface extending in a direction perpendicular to the axis and rotated around the axis, and a carrier that holds a flat object to be polished relative to the surface plate so as to be rotatable relative to the surface plate. Used in polishing machines,
A polishing body fixed to the fixed surface and polishing the object to be polished under a predetermined surface pressure in the presence of a polishing liquid,
A polishing pad made of polyvinylidene fluoride and having a base material in which a plurality of pores are formed, and abrasive particles held within the base material or within the pores;
a cushion layer made of an elastically deformable silicone-based porous body and removably adsorbed to the fixed surface;
A polishing body comprising: an adhesive layer containing a silicone-based adhesive component, interposed between the polishing pad and the cushion layer, and bonding the polishing pad and the cushion layer. The polishing pad has a pad-side impregnated layer impregnated with the adhesive component at the interface with the adhesive layer,
The polishing body according to claim 1, wherein the cushion layer has a cushion-side impregnated layer impregnated with the adhesive component at an interface with the adhesive layer. The polishing body according to claim 1 or 2, wherein the cushion layer has a thickness of 100 μm to 500 μm.

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