KR102831572B1 - Waste polishing pad - Google Patents

Abstract

The present invention provides a polishing pad having an upper pad having grooves formed therein and a lower pad positioned below the upper pad, wherein the polishing pad has a Cp value expressed by Equation 1 of 0.10 to 1.3.

Description

WASTE POLISHING PAD

The present invention relates to a polishing pad.

Chemical Mechanical Polishing (CMP) is a key process for smoothing and polishing wafers or glass panels. Polishing is performed through the mechanical and chemical actions of a polishing pad and slurry containing nanoparticles.

Fig. 1 is a schematic diagram of a CMP device. The CMP device performs polishing by pressing the polishing target (2, e.g., wafer) onto the surface of a polishing pad (6) fixed to a rotary table (1, platen) while the carrier (3) firmly holds the polishing target. Specifically, while the carrier (3) and the rotary table (1) are each independently rotated, a liquid slurry (abrasive) is applied to the polishing pad (6) from a nozzle (5), thereby performing chemical and mechanical polishing. In addition, during the polishing process, a conditioner (4) is pressed onto the polishing pad at a position spaced from the polishing target (1), thereby roughening the surface of the polishing pad and maintaining a rough surface state of the polishing pad.

The polishing pad is one of the main consumables used in the chemical mechanical polishing process. It is made of soft polymer material to improve surface hardening performance, and includes a number of grooves and pores on its surface to efficiently discharge polishing byproducts generated during the polishing process and supply slurry.

Since the polishing pad is constantly exposed to high-hardness nano-abrasive particles and continuous mechanical friction environment with the polishing target, the micro pores on the surface become clogged and the unevenness of the surface responsible for polishing wears out, so the polishing performance deteriorates over time. Therefore, the polishing performance deterioration is prevented through a pad surface conditioning process that periodically grinds the surface.

Polishing pads that have been used for a certain period of time are treated as industrial waste because there is no realistic recycling method. However, as the consumption of polishing pads is gradually increasing and environmental pollution occurs when they are disposed of, intensive research on recycling methods such as regeneration is required.

Conventional techniques for regenerating waste polishing pads include a method of utilizing a compensation material to compensate for the worn portion of the waste polishing pad, and a method of disassembling and reassembling components such as the upper pad and lower pad that make up the waste polishing pad and recycling them.

However, these methods do not satisfy the economic feasibility in terms of the efficiency of regeneration of waste polishing pads. In addition, in the regeneration process, the existing polishing surface is ground and flattened, and a new groove is formed on the flat surface. However, since the pore shape of the flat surface is damaged by the pressure and friction applied during the grinding process, there is a problem in that the roughness of the polishing surface of the regenerated polishing pad is not sufficiently secured.

Republic of Korea Publication Patent No. 10-2020-0139907

The present invention has been devised to solve the above problems of the prior art.

The purpose is to provide a polishing pad that has polishing performance comparable to that of a new polishing pad and excellent flatness, even when a used polishing pad is reused.

In addition, the purpose is to provide a regenerated polishing pad having excellent polishing performance manufactured by the above-mentioned regenerative method.

In order to achieve the above purpose, the present invention

A polishing pad having an upper pad having grooves formed thereon and a lower pad positioned below the upper pad,

The above polishing pad provides a polishing pad having a Cp value of 0.10 to 1.3, as expressed by the following formula 1.

[Formula 1]

Cp = Compression ratio x Thickness change rate/100

The polishing pad of the present invention regenerates a waste polishing pad through a simple process, thereby providing excellent regeneration efficiency and polishing performance comparable to that of a new polishing pad.

In addition, since the polishing pad of the present invention has excellent polishing performance, it can be used in a CMP process without performance degradation due to regeneration.

Figure 1 is a perspective view illustrating the structure of a representative CMP device.
Figure 2 is a cross-sectional view showing one embodiment of a method for manufacturing a polishing pad of the present invention.
Figure 3 is a flow chart showing one embodiment of a method for manufacturing a polishing pad of the present invention.
Figure 4 is a schematic diagram showing one embodiment of the polishing pad of the present invention.
FIG. 5 is a graph illustrating a method for calculating the compression ratio of one embodiment of the polishing pad of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Similar parts are designated by the same drawing reference numerals throughout the specification.

When a component is said to be "connected to, provided with, or installed" another component, it should be understood that it may be directly connected or installed to the other component, but there may also be other components in between. On the other hand, when a component is said to be "directly connected to, provided with, or installed" another component, it should be understood that there are no other components in between. Meanwhile, other expressions that describe the relationship between components, such as "above" and "directly above", or "between" and "directly between", or "adjacent to" and "directly adjacent to", should be interpreted similarly.

FIG. 2 is a cross-sectional view showing one embodiment of a method for manufacturing a polishing pad of the present invention, and FIG. 3 is a flow chart showing one embodiment of a method for regenerating a polishing pad of the present invention. Hereinafter, the method for manufacturing a polishing pad of the present invention will be described with reference to FIGS. 2 and 3.

The method for manufacturing a polishing pad of the present invention is as shown in Fig. 2.

a) A step of separating the adhesive layer (14) on the lower surface of the lower pad (13) from the polishing pad (100);

b) A step of grinding the polishing surface on which the groove (15) of the above polishing pad (100) is formed, and then flattening it;

c) a step of forming a groove (17) on the polishing surface of the polishing pad on which the flattening is completed; and

d) It is characterized by including a step of forming an adhesive layer (14) on the lower surface of the lower pad (13) of the above-mentioned polishing pad.

Conventional polishing pad regeneration technologies include a method of utilizing a compensation material to compensate for the worn portion of the polishing pad, and a method of disassembling and reassembling components such as the upper pad and lower pad that make up the polishing pad to recycle them.

However, these methods are difficult to use in practice due to their low regeneration efficiency and resulting economic downturn.

The present invention has the characteristic of providing excellent roughness to a polishing surface by restoring a pore shape damaged in the grinding process through a grinding treatment, thereby providing polishing performance comparable to that of a new polishing pad.

In one embodiment of the present invention, the flattening step of step b) may be performed by grinding 0.3 mm to 1.3 mm, preferably 0.3 mm to 1.0 mm, more preferably 0.3 mm to 0.8 mm downward from the lowest portion of the groove.

In one embodiment of the present invention, the thickness of the polishing pad that has been flattened in step b) may be 2 mm or more, preferably 2.0 to 3.0 mm, and more preferably 2.5 to 2.9 mm.

Among the polishing pads manufactured in this manner, the thickness of the upper pad may be 0.6 to 1.7 mm, preferably 0.9 to 1.7 mm, more preferably 1.2 to 1.6 mm, and most preferably 1.4 to 1.6 mm.

Additionally, among the polishing pads, the thickness of the lower pad may be 0.7 to 1.4 mm, and preferably 0.8 to 1.3 mm.

In one embodiment of the present invention, the method for regenerating the scrap polishing pad may not perform a separate conditioning process. In the prior art, a conditioning process was performed to restore the damaged roughness. However, the conditioning process is not a process for restoring the damaged pores, but rather forms roughness by scratching the polishing surface pores, so it cannot fundamentally form roughness of the polishing surface, and the effect does not last for a long time.

The present invention solves this problem by a grinding process of the damaged portion, so that sufficient roughness can be provided to the polishing surface, and the effect can be maintained for a long period of time.

In one embodiment of the present invention, a process of washing the polishing pad may be further performed between steps a) and b), and at this time, the washing method is not particularly limited and may be performed by a method known in the art.

In one embodiment of the present invention, the upper pad of the polishing pad may be made of a porous polyurethane material, but is not limited to such a material.

In one embodiment of the present invention, the groove (17) may have a depth of about 0.8 mm to about 1.0 mm, but is not limited thereto. The groove may have a uniform depth or different depths. The process of forming the groove may be performed by a method known in the art.

The present invention provides a regenerated polishing pad regenerated by the above method.

The regenerative polishing pad of the present invention provides excellent roughness to the polishing surface for a long period of time because its physical properties are restored as the polishing surface is ground to a certain thickness.

Hereinafter, with reference to FIG. 4, a polishing pad manufactured in the present invention will be exemplarily described.

The present invention provides a polishing pad having an upper pad having grooves formed therein and a lower pad positioned below the upper pad, wherein the value of Cp expressed by the following Equation 1 is 0.10 to 1.3.

[Formula 1]

Cp = Compression ratio x Thickness change rate/100

The above polishing pad includes an upper pad (11) having grooves formed thereon. The upper pad (11) includes a polishing surface having a plurality of first grooves (17). The grooves (15) support a large flow of slurry on the surface of the polishing pad. The grooves (17) have a depth of about 0.8 mm to about 1.0 mm.

The upper pad (11) may be made of a porous polyurethane material and may have pores that support fine flow, but is not limited thereto.

In some embodiments, the polishing pad may include a first adhesive layer (12), a lower pad (13), and a second adhesive layer (14).

The lower pad (13) positioned below the upper pad may be composed of a material having resilience against a force that presses the substrate, and functions to uniformly support the upper pad (11) by buffering the force. The lower pad (13) may be, for example, a polyurethane foam lower pad, an impregnated felt lower pad, a microporous polyurethane lower pad, a sintered urethane lower pad, or a polyolefin foam lower pad, but is not limited thereto. In general, the lower pad (13) has a lower hardness than the upper pad (11). In addition, the lower pad (13) may have a greater compressibility than the upper pad (11).

The first adhesive layer (12) may be positioned between the upper pad (11) and the lower pad (13) to attach the lower pad (13) to the upper pad (11). The second adhesive layer (14) may be provided between the lower pad (13) and the platen to fix the polishing pad (100) to the rotary table (platen) of the polishing device (FIG. 1). The first adhesive layer (12) and the second adhesive layer (14) may include a pressure sensitive adhesive (PSA) or a hot melt adhesive (HMA). For example, the pressure sensitive adhesive may be an adhesive containing a polyacrylic component, an epoxy component, a rubber component, or the like, or may be a double-sided pressure sensitive adhesive tape in which an adhesive material is applied to both sides of a substrate (e.g., PET film or felt), but is not limited thereto. For example, the hot melt adhesive may be, but is not limited to, a cured reactive hot melt adhesive.

The above polishing pad may have a Cp value of 0.10 to 1.3, as expressed by Equation 1 below.

[Formula 1]

Cp = Compression ratio x Thickness change rate/100

The inventors of the present invention have confirmed that when grinding the upper part of an upper pad in order to reuse a waste polishing pad, the compressibility of the entire polishing pad and the rate of change in thickness of the entire polishing pad have different values depending on the thickness of each of the upper and lower pads of the polishing pad having a specific range, and that after quantifying these values and multiplying them, the polishing performance and flatness of the regenerated polishing pad can have good values.

As a result, the polishing pad of the present invention is characterized in that the polishing performance of the regenerated polishing pad has a good value when the value of Cp represented by the following formula 1 is 0.10 to 1.3.

The value of the above Cp is a value that uses only numbers excluding % when the compression ratio is expressed as a %. In addition, the value of the percentage obtained by dividing the value expressed as the thickness change rate as a % by 100 is used.

For example, for a polishing pad with a compression ratio of 1.4% and a thickness change rate of 26.5%, the value of Cp is 0.37, which is 1.4 multiplied by 0.265.

In the present invention, the value of Cp may be 0.10 or more, 0.13 or more, 0.20 or more, 0.35 or more, 0.65 or more, 0.85 or more, 1.0 or more, 1.20 or more, and may be 1.3 or less, 1.0 or less, 0.80 or less, 0.60 or less, 0.45 or less, 0.20 or less.

When the value of the above Cp is lower than 0.10, there is little improvement in pad performance due to recycling as a regenerative pad, and when it is higher than 1.3, there is a problem of reduced polishing performance.

In one embodiment of the present invention, the thickness of the polishing pad may be 2 mm or more, preferably 2.0 to 3.0 mm, more preferably 2.5 to 2.9 mm.

In one embodiment of the present invention, the thickness of the upper pad may be 0.6 to 1.7 mm, preferably 0.9 to 1.7 mm, more preferably 1.2 to 1.6 mm, and most preferably 1.4 to 1.6 mm.

In one embodiment of the present invention, the thickness of the lower pad may be 0.7 to 1.4 mm, preferably 0.8 to 1.3 mm.

In one embodiment of the present invention, the thickness change rate of the above formula 1 is a ratio of the current thickness to the thickness of the initially manufactured polishing pad, and can be specified through the following formula 2.

[Formula 2]

Thickness change rate (%) = (initial pad thickness - pad thickness during analysis) x 100 / initial pad thickness

In one embodiment of the present invention, the polishing pad may have a polishing performance of 2,000 to 2,650 A/min.

In one embodiment of the present invention, the lower pad may have a compression ratio of 1 to 8%.

In the present invention, the compression ratio can be measured by the following Equation 3, and the following Equation 3 can be specifically calculated through FIG. 5.

[Formula 3]

Compression ratio (%) = (L3-L4) x 100/L3

(The above L3 is the initial thickness of the second cycle when measuring the compression ratio in a viscoelastic device, and the above L4 is the thickness at the second 30-second loading.)

Specifically, referring to FIG. 5, the L3 and L4 are respectively measured twice with a prepared specimen (5x5 cm) in a viscoelastic device at 1500 g for a loading time of 30 seconds and an unloading time of 30 seconds, the initial thickness of the second cycle is L3, and the thickness at the second 30-second loading is L4.

The above compression ratio may be 1% or more, 2% or more, 4% or more, or 6% or more, and may be 8% or less, 6% or less, or 4% or less. If the compression ratio is less than 1%, there is a problem that the polishing uniformity for the entire surface of the wafer is small during the CMP polishing process, resulting in polishing unevenness. If the compression ratio exceeds 8%, even if the pad is regenerated, the pad life time for which the actual pad can be used is too short, making it difficult to apply to the polishing process.

In addition, if the compression ratio is too low, uneven polishing occurs, so the pad can be designed to secure polishing uniformity by attaching a pad with compression characteristics to the bottom of a high-hardness top pad.

In one embodiment of the present invention, the polishing pad may be a regenerated polishing pad that is used by regenerating a waste polishing pad.

Hereinafter, the present invention will be described in detail by way of examples in order to specifically explain the present invention. However, the examples according to the present invention may be modified in various different forms, and the scope of the present invention should not be construed as being limited to the examples described below. The examples of the present invention are provided in order to more completely explain the present invention to a person having average knowledge in the art.

Example 1: Polishing pad regeneration

[Examples 1-1 to 1-6 and Comparative Example 1-1]

The same type of polishing pads that were discarded after use were obtained and the thickness of the upper pad was measured. The thickness of the upper pad was 1.9 mm, the thickness of the lower pad was 1.4 mm, and the initial thickness of the pad before use was 3.3 mm. The compression ratio of the lower pad was 6%.

The reproduction process was carried out as follows.

First, the bonding layer bonded to the lower pad was separated and removed from the waste polishing pad. Next, the waste polishing pad was washed and dried. Next, the polishing surface of the dried waste polishing pad was turned using a lathe to grind the polishing surface to different thicknesses for each example and comparative example, and then the polishing surface was flattened.

Next, a groove was formed on the polishing surface of the waste polishing pad using a groove processing machine (CNC) to regenerate the waste polishing pad. After that, one side of a double-sided adhesive tape was attached to the lower surface of the regenerated polishing pad, and a 1.4 mm thick lower pad was attached to complete the regenerated pad. The lower pad used was the same as the lower pad of the initially used pad.

The results are shown in Table 1 below.

[Examples 2-1 to 2-5 and Comparative Example 2-1]

The same discarded pads as in Example 1 were used to perform a regeneration process, except that the upper pad had a thickness of 1.9 mm, the lower pad had a thickness of 0.8 mm, the initial thickness of the pads before use was 2.7 mm, and the compression ratio of the lower pad was 2.5%. Different thicknesses were ground for each example and comparative example.

Afterwards, one side of a double-sided adhesive tape was attached to the lower surface of the above-mentioned regenerated polishing pad, and a 0.8 mm thick lower pad was attached to complete the regenerated pad. The lower pad used was the same as the lower pad of the pad used initially.

The results are shown in Table 2 below.

[Examples 3-1 to 3-3 and Comparative Example 3-1]

The same discarded pads as in Example 1 were used to perform a regeneration process, except that the upper pad had a thickness of 1.9 mm, the lower pad had a thickness of 1.4 mm, the initial thickness of the pads before use was 3.5 mm, and the compression ratio of the lower pad was 15.0%. Different thicknesses were ground for each example and comparative example.

Afterwards, one side of a double-sided adhesive tape was attached to the lower surface of the above-mentioned regenerated polishing pad, and a 1.4 mm thick lower pad was attached to complete the regenerated pad. The lower pad used was the same as the lower pad of the pad used initially.

The results are shown in Table 3 below.

[Examples 4-1 to 4-4 and Comparative Example 4-1]

The same discarded pads as in Example 1 were used to perform a regeneration process, except that the upper pad had a thickness of 1.55 mm, the lower pad had a thickness of 1.4 mm, the initial thickness of the pads before use was 3.0 mm, and the compression ratio of the lower pad was 10.0%. Different thicknesses were ground for each example and comparative example.

Afterwards, one side of a double-sided adhesive tape was attached to the lower surface of the above-mentioned regenerated polishing pad, and a 1.4 mm thick lower pad was attached to complete the regenerated pad. The lower pad used was the same as the lower pad of the pad used initially.

The results are shown in Table 4 below.

Experimental Example 1: Evaluation of Compression Ratio and Polishing Performance of Regenerated Polishing Pads

The results of the compression ratio, thickness change rate, Cp value, and polishing performance of the manufactured regenerative pad are summarized as follows.

Specifically, the regenerative polishing pads were each attached to the CMP device illustrated in Fig. 1, and the polishing performance for the wafer was evaluated, and the results are shown in Tables 1 to 5 below.

<CMP process conditions>

Polishing table rotation speed (rpm): 120

Carrier rotation speed (rpm): 120

Wafer pressure (psi): 3.0

Slurry flow rate (fumed silica), 240 ml/min

Polishing time (sec): 60

<Method of measuring compression ratio>

In the present invention, the compression ratio refers to a value indicating the degree to which the volume of an object is likely to change when force is applied to the object. The calculation of the compression ratio in the present invention is as follows.

1) Preparation

Pad size (width X height): 5cm X 5cm

Viscoelasticity Meter (VMS, GNP)

Maintain constant temperature and humidity (25℃ 50%RH)

2) Measurement

- Condition: Measuring Cycle: 2

Loading Time: 30

Unloading Time: 30

- Calculation: First, calculate the compression ratio as L3 and L4 as shown in the graph.

Here, the L3 is the initial thickness of the second cycle when measuring the compression ratio in a viscoelastic device, and the L4 is the thickness at the second 30-second loading.

Specifically, referring to FIG. 5, the L3 and L4 are respectively measured twice with a prepared specimen (5x5 cm) in a viscoelastic device at 1500 g for a loading time of 30 seconds and an unloading time of 30 seconds, the initial thickness of the second cycle is L3, and the thickness at the second 30-second loading is L4.

This value represents the second cycle compression amount. After that, the compression ratio is calculated as in Equation 3 below.

[Formula 3]

Compression ratio (%) = (L3-L4) x 100 / L3

pad gun
Thickness (mm) First preparation
Thickness change rate (%) Full pad
compressibility(%) Cp* Polishing performance
(A/min) Pad life time (hr)** Example 1-1 3 11.8 0.95 0.11 2650 25.7 Example 1-2 2.9 14.7 1.1 0.16 2500 - Example 1-3 2.7 20.6 1.3 0.27 2450 - Example 1-4 2.5 26.5 2.5 0.66 2300 - Example 1-5 2.3 32.4 3 0.97 2200 - Example 1-6 2.1 38.2 3 1.15 2100 - Comparative Example 1-1 1.8 47.1 4 1.88 800 -

*Cp = Compression ratio x Thickness change rate/100

**Pad life time: The time available for use when predicting pad availability range based on Cp

pad gun
Thickness (mm) First preparation
Thickness change rate (%) Full pad
compressibility(%) Cp* Polishing performance
(A/min) Pad life time (hr) Example 2-1 2.4 20.0 0.9 0.18 2800 22.9 Example 2-2 2.2 26.7 1.51 0.40 2700 - Example 2-3 2 33.3 2 0.67 2500 - Example 2-4 1.8 40.0 2.2 0.88 2300 - Example 2-5 1.6 46.7 2.3 1.07 2100 - Comparative Example 2-1 1.2 60 2.5 1.44 700 -

pad gun
Thickness (mm) First preparation
Thickness change rate (%) Full pad
compressibility(%) Cp* Polishing performance
(A/min) Pad life time (hr) Example 3-1 3.3 8.6 6 0.51 2300 8.6 Example 3-2 3.2 5.7 7 0.40 2100 - Example 3-3 3 14.3 8 1.14 2000 - Comparative Example 3-1 2.5 28.6 9 2.57 2300 -

pad gun
Thickness (mm) First preparation
Thickness change rate (%) compressibility(%) Cp* Polishing performance
(A/min) Pad life time (hr) Example 4-1 2.9 3.3 3.5 0.12 2500 14.3 Example 4-2 2.7 10.0 4 0.40 2300 - Example 4-3 2.5 16.7 4.8 0.80 2200 - Example 4-4 2.4 20.0 5.5 1.10 2100 - Comparative Example 4-1 2.3 23.3 6.3 1.47 1800 --

From the experimental results in Tables 1 to 4 above, it was confirmed that a certain level of polishing performance or higher could be secured when each polishing pad sample was ground to a certain thickness satisfying a certain range of Cp values of 0.10 to 1.3 and then regenerated.

However, in the case of Comparative Examples 1-1 to 4-1, it was confirmed that polishing performance was not secured and therefore it was not easy to use it as a regeneration pad.

In addition, for Example 1 described in Table 1, the time taken to start using Example 1-1, which is actually used as a recycled pad, and use it until the pad of Example 1-6, which is the last level of pad that can be used as a pad, was defined as pad life time, and through this, the time for which the recycled pad can actually be used was predicted. For specific calculations, when calculating based on a pad wear rate of 35 um/hr, it was predicted that it could be used for approximately 25.7 hours through the calculation of 0.9*1000/35.

Similarly, in the case of Example 2 described in Table 2, the pad life time was calculated using the pad of Example 2-1 until the pad of Example 2-5 was used, and it was predicted that it could be used for approximately 22.9 hours through the calculation of 0.8*1000/35.

Similarly, in the case of Example 3 described in Table 3, the pad life time was calculated using the pad of Example 3-1 until the pad of Example 3-3 was used, and it was predicted that it could be used for about 8.6 hours through the calculation of 0.3*1000/35.

Similarly, in the case of Example 4 described in Table 4, when the pad of Example 4-1 was used to calculate the pad life time until the pad of Example 4-4 was used, it was predicted that it could be used for about 14.3 hours through the calculation of 0.5*1000/35.

In the case of the regenerative pad, a usage time of at least 20 hours or more must be secured. However, in cases where the compression ratio of the lower pad satisfies the range of 1 to 8%, such as in Examples 1 and 2, a sufficient usage time of at least 20 hours is secured. On the other hand, in cases of Examples 3 and 4 where the compression ratio of the lower pad exceeds 8%, the usage time of the regenerative pad is low, which significantly reduces the utility of recycling. It was confirmed that this is a problem.

11: Top pad 12: First adhesive layer
13: Lower pad 14: Second adhesive layer
15, 17: Groove 100: Waste Grinding Pad
200: Regeneration polishing pad

Claims (10)

A polishing pad having an upper pad having grooves formed thereon and a lower pad positioned below the upper pad,
The above polishing pad has a Cp value of 0.10 to 1.3, as expressed by the following formula 1.
A polishing pad, characterized in that the lower pad has a compression ratio of 2 to 8%.
[Formula 1]
Cp = Compression ratio x Thickness change rate/100 In the first paragraph,
A polishing pad, characterized in that the thickness of the polishing pad is 2.0 to 3.0 mm. In the second paragraph,
A polishing pad, characterized in that the thickness of the upper pad is 0.6 to 1.7 mm. In the second paragraph,
A polishing pad, characterized in that the thickness of the lower pad is 0.7 to 1.4 mm. In the first paragraph,
A polishing pad, characterized in that the upper pad is made of a porous polyurethane material. In the first paragraph,
A polishing pad, characterized in that the lower pad is at least one of a polyurethane foam lower pad, an impregnated felt lower pad, a microporous polyurethane lower pad, a sintered urethane lower pad, or a polyolefin foam lower pad. delete In the first paragraph,
A polishing pad, characterized in that the thickness change rate of the above formula 1 is a ratio of the current thickness to the thickness of the initially manufactured polishing pad. In the first paragraph,
A polishing pad, characterized in that the above polishing pad has a polishing performance of 2,000 to 2,650 A/min. In the first paragraph,
The above polishing pad is a polishing pad characterized in that it is a regenerated polishing pad that is used by regenerating a waste polishing pad.