Recycled polishing pad and method for manufacturing the same

Abstract

This invention provides a reusable polishing pad with excellent CMP performance, enabling the achievement of desired polishing rates and polishing uniformity, including a reusable polishing layer having a predetermined compression ratio. [Solution] According to an embodiment of the present invention, a reusable polishing pad and a method for manufacturing a reusable polishing pad are provided. The reusable polishing pad includes a cushion layer, an adhesive layer, and a reusable polishing layer having a plurality of grooves on one surface, and the polishing layer can be reused while maintaining excellent polishing efficiency and polishing uniformity by adjusting the compression ratio of the reusable polishing layer, calculated by a specific formula, to a predetermined range.

Description

[Technical Field]

[0001] This invention relates to a regenerative polishing pad and a method for manufacturing the same. [Background technology]

[0002] Chemical mechanical planarization (CMP) processes can be performed for various purposes in various technological fields. For example, CMP processes can be used to planarize the surfaces of materials and substrates used in semiconductor devices, electronic components, optical components, etc., for purposes such as removing aggregated material, eliminating crystal lattice damage, and removing surface defects and sources of contamination.

[0003] In the CMP (Chemical Polishing) process, polishing pads may be used to polish the surface of the object to be polished. Because the polishing pads directly interact with the surface of the object to be polished, they can affect the processing quality of the object. For example, the polishing characteristics of the CMP process can change sensitively depending on the components contained in the polishing pad and the physical properties of the polishing pad.

[0004] Recently, with the emergence of environmental problems such as climate change, public opinion is forming that companies should take on social responsibility to build a sustainable society through ESG management, including carbon neutrality. Polishing pads used in the CMP process are consumables and are discarded without being reused, which can cause environmental pollution. Therefore, attempts are being made to recycle used polishing pads.

[0005] On the other hand, as the CMP process progresses, the pad layer of the polishing pad may wear down or its thickness may decrease. Conventionally, methods have been studied to reuse polishing pads by adding or replenishing a new pad layer to used polishing pads in order to achieve the desired CMP performance. However, in this case, a new pad layer is required to reuse the polishing pad, which complicates the process, increases costs, and can lead to further environmental problems in the production process of the new pad layer.

[0006] Therefore, it is necessary to develop technologies that can increase the recycling rate while possessing excellent physical properties to satisfy the performance requirements of the CMP process. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Korean Registered Patent No. 10-0418648 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The technical problem that this invention aims to solve is to provide a regenerated polishing pad that can achieve a desired polishing rate and polishing uniformity, including a reusable polishing layer having a predetermined compression ratio, and that has excellent CMP performance.

[0009] Furthermore, the present invention provides a method for manufacturing a regenerated polishing pad using a reusable polishing layer having a predetermined compression ratio from a used polishing pad. [Means for solving the problem]

[0010] An example of an implementation of the present invention includes a polishing pad comprising a cushion layer, an adhesive layer formed on the cushion layer, and a reusable polishing layer attached to the adhesive layer and having grooves on one surface, wherein the compressibility of the reusable polishing layer, calculated by the following formula 1, is 0.9% or more. [Formula 1] JPEG0007870386000001.jpg880

[0011] In the above formula 1, T1 is the thickness (mm) of the reused polishing layer measured by applying pressure to the reused polishing layer with a load of 85g for 30 seconds, and T2 is the thickness (mm) of the reused polishing layer measured by applying additional pressure to the reused polishing layer with a load of 885g for 3 minutes after the measurement of T1.

[0012] In the method for manufacturing a reclaimed polishing pad according to another embodiment of the present invention, a polishing layer is recovered from the polishing pad used in the CMP process, one surface of the polishing layer is flattened, grooves are formed on one surface of the flattened polishing layer to manufacture a reused polishing layer, and a cushion layer can be attached to the other surface of the reused polishing layer using an adhesive. The compression ratio of the reused polishing layer calculated by the above formula 1 can be 0.9% or more.

Advantages of the Invention

[0013] According to an embodiment of the present invention, the reclaimed polishing pad can provide improved polishing rate and polishing uniformity, including a reused polishing layer having a compression ratio within a specific range.

[0014] In addition, when the reused polishing layer has a compression ratio within the above range and includes grooves with a predetermined depth, more excellent physical properties and polishing characteristics of the reclaimed polishing pad are maintained, and it can be suitably used in the polishing process.

[0015] According to another embodiment of the present invention, by manufacturing a reused polishing pad by recovering a polishing layer having a compression ratio within a specific range from a polishing pad used and discarded in the polishing process, additional replenishment pads are not required, so the recycling process is simplified and the process cost can be reduced.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a reclaimed polishing pad according to an embodiment of the present invention. [Figure 2a] FIG. 2a is a schematic cross-sectional view showing a part of the polishing pad at each stage of the method for manufacturing a reclaimed polishing pad according to an embodiment. [Figure 2b] FIG. 2b is a schematic cross-sectional view showing a part of the polishing pad at each stage of the method for manufacturing a reclaimed polishing pad according to an embodiment. [Figure 2c] FIG. 2c is a schematic cross-sectional view showing a part of the polishing pad at each stage of the method for manufacturing a reclaimed polishing pad according to an embodiment. [Figure 2d]Figure 2d is a schematic cross-sectional view showing a portion of the polishing pad at each stage of the manufacturing method for a regenerated polishing pad according to one implementation example. [Figure 2e] Figure 2e is a schematic cross-sectional view showing a portion of the polishing pad at each stage of the manufacturing method for a regenerated polishing pad according to one implementation example. [Figure 3a] Figure 3a is a graph showing the polishing rates of the central region (Center), the middle region (Middle), and the edge region (Edge) as measured in Experimental Example 1. [Figure 3b] Figure 3b is a graph showing the polishing rates of the central region, intermediate region, and edge region as measured in Experimental Example 1. [Figure 3c] Figure 3c is a graph showing the polishing rates of the central region, the intermediate region, and the edge region as measured in Experimental Example 1. [Figure 4a] Figure 4a is a graph showing the polishing rate profile as measured by Experimental Example 1, based on the distance from the center. [Figure 4b] Figure 4b is a graph showing the polishing rate profile as measured by Experimental Example 1, based on the distance from the center. [Figure 4c] Figure 4c is a graph showing the polishing rate profile as measured by Experimental Example 1, based on the distance from the center. [Figure 5a] Figure 5a is a graph showing the polishing rates of the central region, the intermediate region, and the edge region as measured in Experimental Example 3. [Figure 5b] Figure 5b is a graph showing the polishing rates of the central region, the intermediate region, and the edge region as measured in Experimental Example 3. [Figure 5c] Figure 5c is a graph showing the polishing rates of the central region, the intermediate region, and the edge region as measured in Experimental Example 3. [Figure 6a] Figure 6a is a graph showing the polishing rates of the central region, the intermediate region, and the edge region as measured in Experimental Example 4. [Figure 6b]Figure 6b is a graph showing the polishing rates of the central region, the intermediate region, and the edge region as measured in Experimental Example 4. [Figure 7a] Figure 7a is a graph showing the polishing rate profile as measured by Experimental Example 4, based on the distance from the center. [Figure 7b] Figure 7b is a graph showing the polishing rate profile as measured by Experimental Example 4, based on the distance from the center. [Figure 8a] Figure 8a is an SEM image taken at 5x magnification of a cross-section of a portion of the polishing pad of Example 1. [Figure 8b] Figure 8b is an SEM image taken at 5x magnification of a cross-section of a portion of the polishing pad of Example 1. [Figure 9a] Figure 9a is an SEM image taken at 5x magnification of a cross-section of a portion of the polishing pad of Comparative Example 1. [Figure 9b] Figure 9b is an SEM image taken at 5x magnification of a cross-section of a portion of the polishing pad of Comparative Example 1. [Figure 10a] Figure 10a is an SEM image taken at 100x magnification of a cross-section of a portion of the polishing layer of the polishing pad of Example 1. [Figure 10b] Figure 10b is an SEM image taken at 100x magnification of a cross-section of a portion of the polishing layer of the polishing pad of Comparative Example 1. [Modes for carrying out the invention]

[0017] The present invention will be described in detail below with reference to various implementation examples and embodiments. The implementation examples are not limited to those disclosed below and can be modified in various forms as long as the essence of the invention is not altered.

[0018] In this specification, terms used to refer to each component are used to distinguish them from other components and are not intended to limit the examples of implementation. Furthermore, in this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0019] In this specification, when a part "includes" a component, this means, unless otherwise stated, that it may include other components rather than excluding them.

[0020] In this specification, any description of one component being formed above / below another, or being connected or joined to one another, includes all instances of direct or indirect formation, connection, or joining between these components. Furthermore, the criteria for above / below each component should be understood to vary depending on the direction from which the object is observed.

[0021] All numerical ranges indicating physical properties, dimensions, etc., of the constituent components described herein should be understood to be modified by the term "approximately" in all cases, unless otherwise specified.

[0022] In the numerical ranges that limit the size, physical properties, etc., of the components described herein, if numerical ranges limited only by upper limits and numerical ranges limited only by lower limits are given as separate examples, it should be understood that the numerical ranges formed by combining these upper and lower limits are also included in the exemplary ranges.

[0023] In this specification, terms such as "first," "second," etc., are used to describe various components, and such components should not be limited by such terms. The terms are used for the purpose of distinguishing one component from another.

[0024] [Recycled polishing pads] Figure 1 is a schematic cross-sectional view showing a regenerated polishing pad according to one embodiment of the present invention. Referring to Figure 1, the reusable polishing pad 200 may include a reuse polishing layer 210, an adhesive layer 220, and a cushioning layer 230. The reuse polishing layer 210, the adhesive layer 220, and the cushioning layer 230 may be laminated sequentially.

[0025] The reused polishing layer 210 may originate from polishing pads that have been used and discarded in the polishing process. For example, the polishing layer contained in used waste polishing pads can be recovered and used in the manufacturing process of the recycled polishing pads 200 described later.

[0026] Grooves 215 may be formed on one surface of the reusable polishing layer 210. For example, the reusable polishing layer 210 may have a plurality of grooves 215 on its first surface and be attached to the cushion layer 230 by a second surface opposite to the first surface. The first surface may be provided as a polishing surface that comes into direct contact with the object to be polished during the polishing process. The grooves 215 can control the large flow of slurry onto the polishing surface, allowing the object to be polished to be mechanically polished and increasing polishing efficiency.

[0027] The compressibility of the reused polishing layer 210 may be 0.9% or more. The compressibility of the reused polishing layer 210 can be calculated using the following formula 1. [Formula 1] JPEG0007870386000002.jpg880

[0028] In formula 1, T1 is the thickness (mm) of the reused polishing layer measured by applying pressure to the reused polishing layer with a load of 85g for 30 seconds, and T2 is the thickness (mm) of the reused polishing layer measured by applying additional pressure to the reused polishing layer with a load of 885g for 3 minutes after the measurement of T1. The compression ratio may also be measured based on test pieces manufactured by cutting the reused polishing layer to a size of 25mm in both the length and width.

[0029] Since the reused polishing layer 210 has a compressibility of 0.9% or more, even if the polishing layer recovered from a discarded polishing pad is reused, the improved polishing rate, polishing uniformity, and flatness achieved by the recycled polishing pad 200 can be provided. Furthermore, even if the reused polishing layer 210 has a relatively lower thickness Ta than the polishing layer of a polishing pad that has not been used in the polishing process, it can maintain excellent physical properties, and the polishing speed can be improved while suppressing defects such as scratches that occur on the surface of the object to be polished.

[0030] According to one example, the compression ratio of the reused polishing layer 210 is 0.9% or more, 1.0% or more, 1.2% or more, 1.5% or more, 1.7% or more, or 1.8% or more, and may be 3.0% or less, 2.8% or less, 2.6% or less, 2.5% or less, 2.3% or less, 2.2% or less, 2.1% or less, or 2.0% or less.

[0031] Specifically, the compressibility of the reused polishing layer 210 is 0.9% to 3.0%, and more specifically, it may be 0.9% to 2.8%, 0.9% to 2.6%, 0.9% to 2.1%, 1.0% to 2.1%, 1.2% to 2.1%, 1.5% to 2.0%, 1.7% to 2.0%, or 1.8% to 2.0%. Within this range, the recycled polishing pad 200 can have improved polishing efficiency and flatness while possessing improved mechanical properties, durability, and stability.

[0032] The ratio D2 / Ta of the groove depth D2 to the thickness Ta of the reusable polishing layer 210 may be 0.7 or less. The thickness Ta of the reusable polishing layer 210 is the straight-line distance between the first and second surfaces of the reusable polishing layer 210, and the depth D of the groove depth D may mean the depth of the recess from the first surface toward the second surface. The thickness Ta of the reusable polishing layer 210 and the depth D2 of the groove depth D2 may be measured in millimeters.

[0033] Since the grooves 215 have a depth within a predetermined range relative to the thickness of the reused polishing layer 210, polishing efficiency and polishing uniformity can be further improved. In addition, the grooves 215 with the aforementioned depth can improve the fluidity of the slurry while trapping debris generated from the polished surface of the reused polishing layer 210.

[0034] The ratio D2 / Ta of the depth D2 of the groove 215 to the thickness Ta of the reused polishing layer 210 is 0.10 or greater, 0.15 or greater, 0.20 or greater, 0.25 or greater, or 0.30 or greater, and may be 0.70 or less, 0.65 or less, 0.50 or less, 0.45 or less, 0.40 or less, or 0.35 or less.

[0035] Specifically, the ratio D2 / Ta may be 0.1-0.7, 0.1-0.65, 0.1-0.5, 0.2-0.5, 0.25-0.45, 0.30-0.45, 0.30-0.40, or 0.30-0.35. Within this range, the polishing removal rate and polishing speed of the regenerated polishing pad 200 can be further improved, and the occurrence of defects on the surface to be polished can be further suppressed.

[0036] According to one embodiment of the present invention, even if the reused polishing layer 210 is obtained from a waste polishing pad and has a relatively thin thickness, the compression ratio and groove depth can satisfy the above range, thereby maintaining the excellent mechanical properties and stability of the recycled polishing pad 200, and substantially improving the polishing performance and flatness compared to the existing polishing pad before it was used in the polishing process.

[0037] The ratio D2 / Tb of the groove depth D2 to the overall thickness Tb of the regenerated polishing pad 200 may be 0.2 or less. The overall thickness Tb of the regenerated polishing pad 200 and the groove depth D2 of the groove 215 may be measured in millimeters. This improves polishing flatness and efficiency, and ensures the hardness, durability, etc. required for the polishing process.

[0038] Specifically, the ratio D2 / Tb of the depth of the groove 215 to the overall thickness of the regenerated polishing pad 200 is 0.2 or less, 0.19 or less, 0.18 or less, 0.17 or less, 0.16 or less, or 0.15 or less, and may be 0.05 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.10 or more, or 0.12 or more.

[0039] In one implementation example, the ratio D2 / Tb may be 0.05~0.2, 0.07~0.19, 0.09~0.18, 0.10~0.18, 0.10~0.17, 0.10~0.16, or 0.12~0.15. Within this range, the strength and durability of the regenerated polishing pad 200 can be ensured, and the polishing performance can be further improved.

[0040] The depth D2 of the groove 215 may be 0.75 mm or less. For example, the depth of the groove 215 may be 0.10 mm or more, 0.15 mm or more, 0.20 mm or more, 0.25 mm or more, 0.30 mm or more, or 0.35 mm or more, and may be 0.75 mm or less, 0.70 mm or less, 0.65 mm or less, 0.60 mm or less, 0.55 mm or less, 0.50 mm or less, 0.48 mm or less, or 0.45 mm or less. This allows the flow of the polishing slurry to be controlled within a desired range, enabling smooth supply and discharge of the polishing slurry, and potentially further improving polishing efficiency and uniformity.

[0041] Specifically, the depth D2 of the groove 215 may be 0.10mm to 0.75mm, 0.15mm to 0.70mm, 0.2mm to 0.65mm, 0.25mm to 0.60mm, 0.25mm to 0.55mm, 0.25mm to 0.50mm, 0.30mm to 0.50mm, 0.30mm to 0.48mm, or 0.35mm to 0.45mm.

[0042] The thickness Ta of the reusable polishing layer 210 is 0.5 mm or more, 0.7 mm or more, 0.8 mm or more, 0.9 mm or more, or 1.0 mm or more, and may be 2.0 mm or less, 1.8 mm or less, 1.6 mm or less, 1.5 mm or less, 1.3 mm or less, or 1.2 mm or less. Specifically, the thickness Ta of the reusable polishing layer 210 may be 0.5 mm to 2.0 mm, 0.7 mm to 1.8 mm, 0.8 mm to 1.6 mm, 0.8 mm to 1.5 mm, 0.9 mm to 1.3 mm, 0.9 mm to 1.2 mm, or 1.0 mm to 1.2 mm. This makes it easy to control the mechanical properties of the reusable polishing layer 210, such as hardness and tensile strength, within a desired range, and may further improve the stability and durability of the recycled polishing pad 200.

[0043] The overall thickness Tb of the recycled polishing pad 200 is 1.5 mm or more, 1.7 mm or more, 1.8 mm or more, 1.9 mm or more, or 2.0 mm or more, and may be 6.0 mm or less, 5.0 mm or less, 4.5 mm or less, 4.0 mm or less, 3.5 mm or less, 3.0 mm or less, or 2.6 mm or less. Specifically, the overall thickness of the recycled polishing pad 200 may be 1.5 mm to 6.0 mm, 1.7 mm to 5.0 mm, 1.8 mm to 4.5 mm, 1.9 mm to 4.0 mm, 2.0 mm to 3.5 mm, 2.0 mm to 3.0 mm, or 2.0 mm to 2.6 mm.

[0044] The hardness of the reused polishing layer 210 can be 40 Shore D to 70 Shore D, 45 Shore D to 65 Shore D, 45 Shore D to 60 Shore D, 50 Shore D to 60 Shore D, or 50 Shore D to 55 Shore D.

[0045] The density of the reused polishing layer 210 is 0.710 g / m 3 ~0.770 g / m 3 、0.710 g / m 3 ~0.760 g / m 3 、0.720 g / m 3 ~0.750 g / m 3 、0.720 g / m 3 ~0.745 g / m 3 、0.725 g / m 3 ~0.745 g / m 3 、または0.730 g / m 3 ~0.740 g / m 3 and may be.

[0046] The tensile strength of the reused polishing layer 210 is 5 N / mm 2 ~30 N / mm 2 、10 N / mm 2 ~25 N / mm 2 、15 N / mm 2 ~25 N / mm 2 、または18 N / mm 2 ~22 N / mm 2 and may be.

[0047] The reusable polishing layer 210 may have a porous structure. For example, the reusable polishing layer 210 may contain multiple pores on its surface and internally. These pores support the fine flow of the polishing slurry, and the supply or discharge of the polishing slurry can be appropriately regulated by the pores.

[0048] In some implementation examples, the average diameter (D) of the multiple pores 50 The average diameter of the pores can be 10 μm to 30 μm, 10 μm to 27 μm, 12 μm to 25 μm, 14 μm to 22 μm, or 16 μm to 20 μm. Depending on the average diameter of the pores, the surface condition of the polishing pad, the fluidity of the polishing slurry, and the polishing efficiency may change.

[0049] The average diameter of the aforementioned pores (D 50 ) can be obtained by 3D CT scanning. For example, the unit area (1 cm²) of the reusable polishing layer. 2 Based on this, pores inside the reused polishing layer can be measured using 3D CT scanning, and the diameter, area, volume, and number of pores can be calculated using CT data analysis and visualization software such as volume graphics. For example, the volume of a pore with diameter r is 4πr 3 The average diameter (D 50 ) can be defined as the diameter of a stoma at which the volume fraction reaches 50% in the volume distribution obtained by accumulating stomata in ascending order of diameter.

[0050] The compression ratio of the regenerated polishing pad 200 may be 0.25% or higher. The compression ratio of the regenerated polishing pad 200 can be calculated using the following formula 2. [Formula 2] JPEG0007870386000003.jpg9128

[0051] In the above formula 2, T3 is the thickness (mm) of the regenerated polishing pad measured by applying pressure to the regenerated polishing pad with a load of 85g for 30 seconds, and T4 is the thickness (mm) of the regenerated polishing pad measured by applying additional pressure to the regenerated polishing pad with a load of 885g for 3 minutes after the measurement of T3.

[0052] The recycled polishing pad 200 has a compression ratio of 0.25% or more, which can further improve polishing flatness and polishing rate, suppress the occurrence of scratches on the workpiece, and further improve polishing quality.

[0053] In one implementation example, the compression ratio of the regenerated polishing pad 200 is 0.25% or more, 0.5% or more, 0.9% or more, 1.0% or more, 1.2% or more, 1.5% or more, 1.7% or more, 1.8% or more, or 2.0% or more, and may be 4.0% or less, 3.8% or less, 3.5% or less, 3.0% or less, 2.8% or less, or 2.5% or less.

[0054] Specifically, the compression ratio of the recycled polishing pad 200 is 0.25% to 4.0%, 0.5% to 3.8%, 0.9% to 3.5%, 0.9% to 3.0%, or 1.0% to 3.0%, and more specifically, it may be 1.2% to 3.0%, 1.2% to 2.8%, 1.5% to 2.8%, 1.7% to 2.8%, 1.8% to 2.5%, or 2.0% to 2.5%. Within the above range, the stability and durability of the polishing pad, the polishing rate and polishing quality on the material to be polished, etc., can be further improved.

[0055] In some implementation examples, the compression ratio of the recycled polishing pad 200 may be greater than that of the reused polishing layer 210.

[0056] The hardness of the regenerated polishing pad 200 may be 35 Shore D to 55 Shore D, 38 Shore D to 55 Shore D, 40 Shore D to 50 Shore D, or 40 Shore D to 45 Shore D. In one implementation example, the hardness of the regenerated polishing pad 200 may be lower than the hardness of the reused polishing layer 210.

[0057] The reusable polishing layer 210 can be in direct contact with the adhesive layer 220. In one implementation, the cushion layer 230, the adhesive layer 220, and the reusable polishing layer 210 can be laminated in sequential contact. For example, no other additional pad layers, such as sub-pads or replenishment pads, need to be interposed between the reusable polishing layer 210 and the cushion layer 230. The reusable polishing layer 210 can have a compression ratio within the aforementioned range, the depth of the groove 215 can be adjusted to a predetermined range, and it can have excellent physical properties even without the addition of additional pad layers, thus providing the improved polishing rate and polishing flatness achieved by the recycled polishing pad 200. Therefore, the cost of the recycling process can be reduced, environmental problems caused by additionally inserted pad layers and yield reductions due to complex processes can be prevented, and the polishing pad can be made lighter, slimmer, and smaller.

[0058] The cushion layer 230 is positioned beneath the reusable polishing layer 210 and stably supports the reusable polishing layer 210 while absorbing and dispersing the impact applied to the reusable polishing layer 210. In one implementation example, the cushion layer 230 may be made from a material that has not been used in the polishing process.

[0059] The cushion layer 230 may include a base material layer such as a nonwoven fabric, suede, or porous pad. In one embodiment, the cushion layer 230 may be manufactured by forming a surface coating layer on the base material layer from a coating composition containing a fluororesin or a silane resin, or it may be manufactured by impregnating the base material layer with a resin containing a fluororesin-modified polyurethane resin or a silane-modified polyurethane resin.

[0060] The thickness of the cushion layer 230 may be, for example, 0.5 mm to 4.0 mm, 0.6 mm to 3.5 mm, 0.8 mm to 3.0 mm, or 1.0 mm to 2.0 mm. Within this range, the recycled polishing pad 200 can be made lighter, and the cushion layer 230 can support the reused polishing layer 210 more stably.

[0061] The thickness of the reusable polishing layer 210 may be less than the thickness of the cushion layer 230. Even if a thin polishing layer is recovered and reused from a worn polishing pad, the cushion layer 230 has a relatively greater thickness than the reusable polishing layer 210, so the reusable polishing pad 200 is stably supported and its durability can be increased.

[0062] The density of cushion layer 230 is 0.20 g / m². 3 ~0.50g / m 3 0.25g / m 3 ~0.45g / m 3 0.30g / m 3 ~0.40g / m 3 , or 0.30 g / m 3 ~0.37g / m 3 It is possible.

[0063] The Shore C hardness of cushion layer 230 can be 50 Shore C to 85 Shore C, 55 Shore C to 80 Shore C, 60 Shore C to 78 Shore C, or 68 Shore C to 76 Shore C.

[0064] The adhesive layer 220 can serve to bond the reusable polishing layer 210 and the cushion layer 220 to each other. Furthermore, the adhesive layer 220 can prevent polishing slurry from flowing out or leaking from the top of the reusable polishing layer 210 into the cushion layer 220.

[0065] In one implementation example, the adhesive layer 220 may be formed using a hot-melt adhesive composition. For example, the adhesive layer 220 may include a hot-melt adhesive having a melting point of 90°C to 130°C or 110°C to 130°C.

[0066] The hot-melt adhesive composition may include commonly known hot-melt adhesives. In one example, the hot-melt adhesive may include polyurethane resins, polyester resins, ethylene-vinyl acetate resins, polyamide resins and / or polyolefin resins, etc. These may be used individually or in combination of two or more.

[0067] The thickness of the adhesive layer 14 may be, for example, 3 μm to 250 μm, 5 μm to 200 μm, 5 μm to 150 μm, 10 μm to 100 μm, 20 μm to 50 μm, or 23 μm to 40 μm. Within this range, the bonding force between the reusable polishing layer 210 and the cushion layer 230 is further enhanced, and the recycled polishing pad 200 can be made even lighter.

[0068] [Method for manufacturing recycled polishing pads] Figures 2a to 2e are schematic cross-sectional views showing parts of the polishing pad at each stage of the manufacturing method for a regenerated polishing pad according to one implementation example.

[0069] Figure 2a is a schematic cross-sectional view showing the polishing pad before it is used in the polishing process.

[0070] Referring to Figure 2a, the polishing pad 100 may include sequentially laminated polishing layers 110, adhesive layers 120, and cushioning layers 130. The polishing layers 110 and cushioning layers 130 may be adhered to each other via the adhesive layers 120.

[0071] The polishing layer 110 may contain polyurethane resin, polyester resin, polyamide resin, acrylic resin, polycarbonate resin, halogen-based resin (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene resin, olefin-based resin (polyethylene, polypropylene, etc.), epoxy-based resin, etc. Specifically, the polishing layer 110 may contain polyurethane resin.

[0072] The abrasive layer 110 may have a porous structure. For example, the abrasive layer 110 may be made from a raw material mixture containing a urethane-based prepolymer, a curing agent, and a foaming agent. The urethane-based prepolymer may be a polymer produced by reacting an isocyanate compound with a polyol.

[0073] A prepolymer generally refers to a polymer with a relatively low molecular weight whose polymerization is stopped at an intermediate stage to facilitate molding in the production of a type of final molded product. Prepolymers can be used on their own or reacted with other polymerizable compounds.

[0074] The foaming agent may include a solid-phase foaming agent, a liquid-phase foaming agent, or a gas-phase foaming agent. Specifically, the foaming agent may include a solid-phase foaming agent. Pores formed on the surface and inside the polished layer 110 may originate from the foaming agent.

[0075] The curing agent may include amine compounds and / or alcohol compounds. For example, the curing agent may include one or more compounds selected from the group consisting of aromatic amines, aliphatic amines, aromatic alcohols, and aliphatic alcohols.

[0076] Grooves 115 may be formed on one surface of the polishing layer 110. For example, the polishing layer 110 may have a plurality of grooves 115 on its first surface and be attached to the cushion layer 130 by a second surface opposite to the first surface. The grooves 115 may have a depth D1 greater than or equal to a predetermined depth. The depth D1 may be a depth that provides performance sufficient for use in the polishing process. For example, if the grooves 115 are too shallow, the polishing rate required in the polishing process may not be achieved.

[0077] The polishing process can be performed on an object to be polished, such as a semiconductor substrate, using the polishing pad 100. The first surface of the polishing layer 110 may be the polishing surface that comes into direct contact with the object to be polished during the polishing process.

[0078] Figure 2b is a schematic cross-sectional view showing a polishing pad that has been worn down during the polishing process.

[0079] Referring to Figure 2b, the polished surface of the polished layer 110 may gradually wear down during the polishing process, such as the CMP process. Due to the wear of the polished surface, the thickness of the polished layer 110 decreases, and the depth of the grooves 115 formed on the polished surface may decrease or collapse. Furthermore, depending on the conditions of the polishing process and the object being polished, the rate of wear on the polished surface may differ from region to region, resulting in the grooves 115 having different depths and the polished surface becoming non-uniform.

[0080] If the depth of the groove 115 decreases or its shape deforms to such an extent that further polishing is no longer possible, the polishing pad 100 may be discarded.

[0081] The discarded polishing pads 100 can be recovered and washed. This washing can remove any impurities or foreign matter remaining on the polishing pads 100 after the polishing process. The washing process is not limited to any method that can wash the discarded polishing pads 100 and remove impurities, and may include, for example, wet washing, chemical washing, dry washing, or mechanical washing.

[0082] Referring to Figure 2c, the abrasive layer 110 can be selectively recovered by removing the adhesive layer 120 and the cushion layer 130 from the discarded abrasive pad 100. For example, the recovery of the abrasive layer 110 can be carried out by a mechanical method of mechanically peeling or separating the adhesive layer 120 from the abrasive layer 110, or by a chemical method of dissolving or decomposing the adhesive layer 120 to remove it.

[0083] Referring to Figure 2d, the polished layer 110 can be flattened. For example, the first surface of the polished layer 110 on which the grooves 115 are formed can be flattened by cutting or milling. The grooves 115 formed on the first surface of the polished layer 110 can be removed by this flattening process.

[0084] In one implementation example, a planarization process may also be performed on the second surface of the polished layer 110. By cutting or milling the second surface, impurities such as adhesive components remaining on the second surface can be removed.

[0085] The planarization process of the polishing layer 110 reduces the thickness of the polishing layer 110, allowing it to be adjusted to the aforementioned thickness range of the regenerated polishing layer. For example, the initial thickness Tc of the polishing layer 110 is reduced to a predetermined thickness through the polishing process, and then further reduced to the thickness range Ta explained in Figure 1 through the planarization process.

[0086] For example, the planarization step may be carried out so that the polished layer 110 has a thickness of 0.5 mm to 2.0 mm, 0.7 mm to 1.8 mm, 0.8 mm to 1.6 mm, 0.8 mm to 1.5 mm, 0.9 mm to 1.3 mm, 0.9 mm to 1.2 mm, or 1.0 mm to 1.2 mm.

[0087] Referring to Figure 2e, a reusable polishing layer 210 can be formed by creating grooves on one surface of the flattened polishing layer 110. For example, the reusable polishing layer 210 may include a plurality of grooves 215 on its first surface.

[0088] In one implementation example, the first surface of the reusable polishing layer 210 can be cut by a chip to form a groove 215. Specifically, the chip can be fixed in contact with the first surface, and the reusable polishing layer 210 can be moved to remove a portion of the first surface.

[0089] The cutting process with the chip may be carried out such that the depth of the groove 215 satisfies the above range. For example, the cutting process may be carried out such that the groove 215 has a depth of 0.10 or more, 0.15 or more, 0.20 or more, 0.25 or more, or 0.30 or more relative to the thickness of the reused polishing layer 210, and a depth of 0.70 or less, 0.65 or less, 0.50 or less, 0.45 or less, 0.40 or less, or 0.35 or less.

[0090] For example, the depth of the groove 215 formed by the cutting process is 0.10 mm or more, 0.15 mm or more, 0.20 mm or more, 0.25 mm or more, 0.30 mm or more, or 0.35 mm or more, and is 0.75 mm or less, 0.70 mm or less, 0.65 mm or less, 0.60 mm or less, 0.55 mm or less, 0.50 mm or less, 0.48 mm or less, or 0.45 mm or less, and specifically, it may be 0.10 mm to 0.75 mm, 0.15 mm to 0.70 mm, 0.2 mm to 0.65 mm, 0.25 mm to 0.60 mm, 0.25 mm to 0.55 mm, 0.25 mm to 0.50 mm, 0.30 mm to 0.50 mm, 0.30 mm to 0.48 mm, or 0.35 mm to 0.45 mm.

[0091] The grooves 215 may have a concentric shape separated by a predetermined interval. Furthermore, a curved surface machining process may be performed to machine the corners of the grooves 215 into curved surfaces. This curved surface machining process may be carried out using a grinder or chalk.

[0092] A recycled polishing pad 200 can be manufactured by laminating a cushion layer 230 onto a reusable polishing layer 210. For example, an adhesive can be applied to the second surface of the reusable polishing layer 210 and / or one surface of the cushion layer 230, and the reusable polishing layer 210 and the cushion layer 230 can be laminated so that the second surface of the reusable polishing layer 210 and the one surface of the cushion layer 230 are in contact, and the laminate can be pressed. This allows for the manufacture of a recycled polishing pad 200 having a structure in which the reusable polishing layer 210, adhesive layer 220, and cushion layer 230 are sequentially laminated, as described in Figure 1.

[0093] According to one embodiment of the present invention, even if the polishing layer obtained from a waste polishing pad is reused, the reused polishing layer 210 has a compression ratio of 0.9% or more, so that the mechanical properties such as hardness, durability, and cutting rate, and the polishing performance such as polishing rate and flatness, can be substantially equivalent to or improved compared to the initial polishing pad 110 before it was used in the polishing process.

[0094] Furthermore, if a reusable polishing layer is manufactured using only the polishing layer obtained from a waste polishing pad without using additional replenishment pads, the thickness Ta of the reusable polishing layer 210 becomes smaller than the thickness Tc of the initial polishing layer 110. According to one embodiment of the present invention, the reusable polishing layer 210 may have improved physical properties and polishing performance by forming grooves 215 such that the reusable polishing layer 210 has the aforementioned compressibility and a predetermined depth ratio with respect to the thickness of the reusable polishing layer 210.

[0095] In one implementation example, during the step of recovering the polishing layer 110 from the discarded polishing pad 100, it is possible to select a polishing layer having a compressibility of 0.9% or more. The compressibility of the polishing layer can be measured by the following formula 3. [Formula 3] JPEG0007870386000004.jpg971

[0096] In the above formula 3, T5 is the thickness (mm) of the polishing layer measured by applying pressure to the polishing layer with a load of 85g for 30 seconds, and T6 is the thickness (mm) of the polishing layer measured by applying additional pressure to the polishing layer with a load of 885g for 3 minutes after the measurement of T5.

[0097] For example, as the polishing process progresses, the compressibility of the polishing layer changes from its initial value, and as a result, the compressibility of the polishing layer contained in the waste polishing pad may have a different value than the initial value. By selectively recovering the polishing layer with a compressibility of 0.9% or higher from the waste polishing pad, the polishing layer can be immediately used in the reuse process without additional processing steps to adjust the compressibility. Therefore, process costs can be reduced, and recycled polishing pads with the desired physical properties and polishing characteristics can be obtained more easily.

[0098] In one implementation example, the compression ratio of the polishing layer 110 obtained from the discarded polishing pad 100 is substantially the same as that of the reused polishing layer, and may be, for example, 0.9%~3.0%, 0.9%~2.8%, 0.9%~2.6%, 0.9%~2.2%, 0.9%~2.1%, 1.0%~2.1%, 1.2%~2.1%, 1.5%~2.0%, 1.7%~2.0%, or 1.8%~2.0%.

[0099] According to an embodiment of the present invention, by including a reusable polishing layer having a specific range of compressibility in the recycled polishing pad, the mechanical properties and polishing efficiency can be further improved while reusing the waste polishing pad, and the surface defect characteristics appearing on the surface of the semiconductor substrate can be improved. Therefore, high-quality semiconductor elements can be efficiently manufactured using the recycled polishing pad.

[0100] (Examples) The present invention will be described in more detail below with reference to the following examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

[0101] (Example 1) (1) Manufacturing of polishing pads Polishing pads were manufactured using a casting apparatus equipped with a urethane-based prepolymer, a curing agent, an inert gas injection line, and an injection line for a reaction rate modifier.

[0102] Specifically, a urethane-based prepolymer (SKC Corporation) containing 9.3% by weight of unreacted NCO was filled into a prepolymer tank, and 4,4'-methylenebis(2-chloroaniline) (ISHIHARA Corporation) was filled into a curing agent tank, with nitrogen (N2) used as the inert gas. In addition, 1 part by weight of a solid-phase foaming agent (Akzonobel Corporation) and 1 part by weight of a silicone-based surfactant (Evonik Corporation) were pre-mixed with 100 parts by weight of the urethane-based prepolymer and injected into the prepolymer tank.

[0103] The raw materials were introduced into the mixing head at a constant rate through each input line while being stirred. The molar equivalents of the NCO groups in the urethane prepolymer and the reactive groups in the curing agent were adjusted to a 1:1 ratio, and the total input rate was maintained at 10 kg / min. The stirred raw materials were extruded into a mold (1000 mm × 1000 mm × 3 mm) and solidified to obtain a molded body.

[0104] The upper and lower ends of the molded body were each cut to a thickness of 0.5 mm to form a polished layer with a thickness of 2.03 mm. The compressibility of the polished layer was measured to be 0.83%. Using a chip, concentric grooves with a width of 0.45 mm and a depth of 0.85 mm were formed on one surface of the polished layer at equal intervals of 3.0 mm.

[0105] A cushion layer with a thickness of 1.3 mm was prepared by impregnating a polyester fiber nonwoven fabric with polyurethane resin. By bonding the polishing layer and the cushion layer using a hot melt adhesive, a polishing pad (thickness: 3.43 mm) having a polishing layer / adhesive layer / cushion layer structure was manufactured.

[0106] (2) Preparation of used polishing pads The polishing pad was fixed to the platen of the CMP apparatus, a tungsten (W) film on a silicon wafer (300 mm in diameter) was set, and the CMP process was performed (polishing load: 2.8 psi, calcined silica slurry applied). The CMP process was repeated until it was determined that the polishing pad was unusable, and the used polishing pad (waste polishing pad) was collected.

[0107] (3) Manufacturing of recycled polishing pads The cushion layer and adhesive layer were removed from the waste polishing pad, and the polishing layer with a compression ratio of 1.89% was selected and recovered. The polishing layer was flattened to form a reusable polishing layer with a thickness of 1.03 mm. Using a tip, concentric grooves with a width of 0.45 mm and a depth of 0.35 mm were formed on one surface of the reusable polishing layer at equal intervals of 3.0 mm.

[0108] A recycled polishing pad containing the aforementioned reused polishing layer as the polishing layer was manufactured. Specifically, a cushion layer with a thickness of 1.3 mm was prepared by impregnating a polyester fiber nonwoven fabric with polyurethane resin. By bonding the reused polishing layer and the cushion layer using a hot melt adhesive, a recycled polishing pad (thickness: 2.43 mm) having a reused polishing layer / adhesive layer / cushion layer structure was manufactured.

[0109] (Example 2) A recycled polishing pad (thickness: 2.43 mm) was manufactured in the same manner as in Example 1, except that in Example 1 (3), a polishing layer having a compression ratio of 1.0% was recovered from a waste polishing pad, flattened, and a reusable polishing layer with a thickness of 1.03 mm was formed.

[0110] (Example 3) A recycled polishing pad (thickness: 2.43 mm) was manufactured in the same manner as in Example 1, except that in Example 1(3), a polishing layer having a compression ratio of 2.2% was recovered from a waste polishing pad, flattened, and a reusable polishing layer with a thickness of 1.03 mm was formed.

[0111] (Example 4) A recycled polishing pad (thickness: 2.43 mm) was manufactured in the same manner as in Example 1, except that, in Example 1 (3), concentric grooves with a width of 0.45 mm and a depth of 0.20 mm were formed on one surface of the reused polishing layer at equal intervals of 3.0 mm.

[0112] (Example 5) A recycled polishing pad (thickness: 2.43 mm) was manufactured in the same manner as in Example 1, except that, in Example 1 (3), concentric grooves with a width of 0.45 mm and a depth of 0.65 mm were formed on one surface of the reused polishing layer at equal intervals of 3.0 mm.

[0113] (Comparative Example 1) A polishing pad (thickness: 3.43 mm) was manufactured using the same method as in (1) of Example 1.

[0114] [Measurement of physical properties of polishing pads] (1) Measurement of compression ratio The compressibility of the polishing layer, regenerated polishing layer, and polishing pad was measured using a dial thickness gauge (Dial Thickness Gauge, 129-E, Yasuda Seiki Co., Ltd.) in an environment of 23°C ± 2°C and 50% ± 5% humidity.

[0115] Specifically, an 85g weight was placed on a 2.5cm x 2.5cm polished layer (recycled polished layer) test specimen for 30 seconds, and the thickness of the specimen (T1 or T5) was measured in millimeters. Then, the weight was increased to 885g, and the thickness of the specimen (T2 or T6) was measured in millimeters after 3 minutes. The compressibility of the polished layer or recycled polished layer was measured using formula 1 or formula 3.

[0116] Furthermore, under the same conditions, the thicknesses T3 (mm) and T4 (mm) of polishing pad test pieces measuring 2.5 cm x 2.5 cm were measured, and the compressibility of the polishing pad was measured using formula 2.

[0117] (2) Hardness measurement Polishing pad test specimens measuring 2 cm x 2 cm were left for 16 hours in an environment of 25°C and 50±5% humidity. Subsequently, the Shore D hardness of the polishing pad and the Shore D hardness of the polishing layer were measured using a D-type hardness tester.

[0118] (3) Density measurement The density of the polishing layer and the polishing pad were measured at 20°C. The density was measured using the Archimedes principle.

[0119] [Table 1]

[0120] (Experimental Example 1: Polishing Rate Evaluation 1) A polishing pad was fixed to the platen of the CMP apparatus, and the silicon oxide film of a silicon wafer (300 mm in diameter) was placed face down before performing the CMP process. Specifically, the polishing load was adjusted as shown in Table 2 below, and the silicon oxide film was polished by rotating the platen at 150 rpm for 60 seconds while silica slurry (ACESOL 2580) was added to the polishing pad at a rate of 190 mL / min. After polishing, the silicon wafer was removed from the carrier and placed in a rotary spin dryer, washed with purified water, and then dried for 15 seconds. The dried silicon wafer was then subjected to a contact surface resistance measuring device (4-point probe) to measure the difference in silicon oxide film thickness before and after polishing at 98 locations (polished thickness), and the average polished thickness was calculated from the measured values. The polishing rate was calculated using the following formula. Polishing rate (Å / min) = Average polishing thickness of silicon wafer (silicon oxide film) (Å) / Polishing time (minutes)

[0121] In Example 1 and Comparative Example 1, the silicon wafer was divided into three regions: the center region (Center) from the center to a radius of 60 mm, the middle region (Middle) from a radius of 60 mm to a radius of 130 mm, and the edge region (Edge) from a radius of 130 mm to a radius of 150 mm. The polishing rate of the center region was calculated using the average value of the measured values ​​(polished thickness) in the center region, the polishing rate of the middle region was calculated using the average value of the measured values ​​in the middle region, and the polishing rate of the edge region was calculated using the average value of the measured values ​​in the edge region.

[0122] The polishing rates of the central region, the intermediate region, and the edge region are shown in Figures 3a to 3c. Specifically, Figure 3a shows the polishing rate measured under a polishing load of 1.7 psi, Figure 3b shows the polishing rate measured under a polishing load of 2.7 psi, and Figure 3c shows the polishing rate measured under a polishing load of 3.7 psi.

[0123] Furthermore, the polishing rate profiles based on the distance from the center are shown in Figures 4a to 4c.

[0124] Referring to Figures 3a-3c and 4a-4c, when the polishing process was performed using the polishing pad of Example 1, a higher polishing rate was observed than in Comparative Example 1 at all evaluation polishing loads. Furthermore, the polishing rate in Example 1 was measured more uniformly across the entire silicon wafer than in Comparative Example 1, confirming superior polishing flatness.

[0125] (Experimental Example 2: Polishing Flatness) From the measured values ​​obtained in the polishing rate evaluation 1 of Experimental Example 1, polishing flatness (WIWNU: Within Wafer Non Uniformity) was calculated using the following formula. Polishing flatness (%) = (Standard deviation of polished thickness (Å) / Average polished thickness (Å)) × 100

[0126] (Experimental Example 3: Polishing Rate Evaluation 2) The polishing rate was evaluated using the same method as in Experimental Example 1, except that the slurry was changed to ceria slurry (ACS-580).

[0127] In Example 1 and Comparative Example 1, the polishing rates in the central, intermediate, and edge regions of the silicon wafer were measured and are shown in Figures 5a to 5c. Specifically, Figure 5a shows the polishing rate measured under a polishing load of 1.7 psi, Figure 5b shows the polishing rate measured under a polishing load of 2.7 psi, and Figure 5c shows the polishing rate measured under a polishing load of 3.7 psi.

[0128] Referring to Figures 5a to 5c, the polishing pad of Example 1 showed substantially the same polishing rate as the polishing pad of Comparative Example 1, confirming that excellent polishing uniformity was maintained.

[0129] (Experimental Example 4: Polishing Rate Evaluation 3) The polishing rate was evaluated using the same method as in Experimental Example 1, except that the target of polishing was changed to a tungsten (W) film on a silicon wafer and the slurry was changed to a silica slurry (SP6730). The difference in thickness of the tungsten film before and after polishing was measured, and the polishing rate was calculated using the following formula. Polishing rate (Å / min) = Polishing thickness of silicon wafer (tungsten film) (Å) / Polishing time (minutes)

[0130] In Example 1 and Comparative Example 1, the polishing rates in the central, intermediate, and edge regions of the silicon wafer were measured and are shown in Figures 6a and 6b, respectively. Specifically, Figure 6a shows the polishing rate measured under a polishing load of 1.7 psi, and Figure 6b shows the polishing rate measured under a polishing load of 2.7 psi.

[0131] Furthermore, the polishing rate profiles based on the distance from the center are shown in Figures 7a and 7b.

[0132] Referring to Figures 6a, 6b, 7a, and 7b, it can be seen that Example 1 shows a higher polishing rate than Comparative Example 1, and that the polishing rate is relatively uniform.

[0133] [Table 2]

[0134] Referring to Table 2 above, when the polishing process was performed using the polishing pad of Example 1, it showed a higher polishing rate and lower polishing flatness than Comparative Example 1, confirming that it was superior in both polishing efficiency and uniformity.

[0135] (Experimental Example 5: Surface roughness of polishing pad) The surface roughness of the polishing pads of Example 1 and Comparative Example 1 was measured using an optical surface roughness meter (Contour GT, Bruker). Specifically, the surface roughness was measured under the following conditions: measurement mode VSI / VXI, eyepiece magnification 5x, objective lens magnification 1.5x, scan speed ×1, backscan 10 μm, length 80 μm, and threshold value 5%. The cumulative data of the measured height per unit area was plotted to obtain an area material ratio curve of surface roughness, and the S-parameter, which is a parameter converted to depth (height) from the area material ratio curve, was derived. Specifically, for the polishing pads, the core roughness depth (Sa), reduced valley depth (Svk), and reduced peak height (Spk) were measured, respectively. The evaluation results are shown in Table 3 below.

[0136] (Experimental Example 6: Debris Size) The polishing pads of Example 1 and Comparative Example 1 were set on the platen of the CMP polishing apparatus. Then, without operating the carrier, debris from the polishing layer was collected using only conditioner and deionized water (DIW). The polishing layer was conditioned by injecting 300 cc / min of deionized water under the following conditions: platen speed 93 rpm, conditioner load 9 lb, rotation speed 64 rpm, and sweep speed 19 times / min. Deionized water was collected during conditioning along with the deionized water. The particle size distribution of the collected debris was obtained using a particle size analyzer (Mastersize 3000, Malvern) and a medium-capacity automatic wet disperser (Hydro MV, Malvern). In the particle size distribution, when the particles were arranged in ascending order of particle size, the D10, D50, and D90 of the debris were measured based on the particle size at the 10%, 50%, and 90% points, respectively. The analyzer was configured with a refractive index of 1.55 for polyurethane as the analyte, a refractive index of 1.33 for deionized water as the dispersant, and a stirring speed of 2500 rpm. The evaluation results are shown in Table 3 below.

[0137] (Experimental Example 7: Cutting Ratio of Polishing Pad) The polishing pads of Example 1 and Comparative Example 1 were pre-conditioned by spraying them with deionized water for 10 minutes. Subsequently, the polishing pads were conditioned by spraying them with deionized water for 1 hour, and the change in the thickness of the polishing pads (μm / hr) before and after conditioning was measured. The CTS AP-300HM device was used for both pre-conditioning and conditioning, with a pressure of 6 lbf and a rotation speed of 100 rpm to 110 rpm, and the disc used was a SAESOL LPX-DS2. The evaluation results are shown in Table 3 below. [Table 3]

[0138] Referring to Table 3 above, the polishing pad of Example 1 had excellent overall physical properties even with the reused polishing layer. Specifically, the surface roughness, debris size, and polishing pad cutting rate were substantially the same as those of Comparative Example 1, which had a new polishing layer.

[0139] (Experimental Example 8: Cross-sectional and surface evaluation of polishing pads) The cross-sections and surfaces of the polishing pads of Example 1 and Comparative Example 1 were photographed using a scanning electron microscope (SEM). Figures 8a and 8b are SEM images of a portion of the cross-section of the polishing pad of Example 1, taken at 5x magnification, and Figures 9a and 9b are SEM images of a portion of the cross-section of the polishing pad of Comparative Example 1, taken at 5x magnification.

[0140] Specifically, Figures 8a and 9a are cross-sectional images of a portion of the polishing pad taken before the polishing rate evaluation, while Figures 8b and 9b are cross-sectional images of a portion of the polishing pad taken after the polishing rate evaluation according to Experimental Example 1.

[0141] Referring to Figures 8a and 8b, in the case of the polishing pad of Example 1, it was confirmed that the shape of the polishing pad had not deformed substantially even after the polishing rate evaluation, and that the grooves and polishing layer had a shape, depth, and thickness that allowed them to be used again in the polishing process.

[0142] On the other hand, referring to Figures 9a and 9b, in the case of the polishing pad of Comparative Example 1, the shape of the polishing pad changed after the polishing process, and the grooves collapsed or the gaps filled in, resulting in a shape that was unsuitable for use in the polishing process.

[0143] Figures 10a and 10b are SEM images taken at 100x magnification of cross-sections of a portion of the polishing layer of the polishing pads of Example 1 and Comparative Example 1, respectively.

[0144] Referring to Figure 10a, it was confirmed that the polishing layer of the polishing pad in Example 1 contained pores and had substantially the same degree of porosity as the polishing layer of the initial polishing pad that was not used in the polishing process in Comparative Example 1.

[0145] (Experimental Example 9: Evaluation of polishing efficiency based on compressibility and groove depth) For the polishing pads of Examples 1-5 and Comparative Example 1, the polishing rate (Å / min) against the silicon oxide film was measured using the same method as in Polishing Rate Evaluation 1 of Experimental Example 1 and Polishing Rate Evaluation 2 of Experimental Example 3. The evaluation results are shown in Tables 4 and 5 below.

[0146] [Table 4]

[0147] [Table 5]

[0148] Referring to Table 4 above, it was confirmed that the polishing rate differed depending on the compression ratio of the polishing layer. Specifically, in Examples 1 to 3, the groove depth, the thickness of the polishing layer, and the thickness of the polishing pad were substantially the same, but the wafer removal rate in the polishing process differed due to the different compression ratios of the polishing layer.

[0149] Referring to Table 5 above, it can be seen that the polishing rate on the wafer differs depending on the ratio of groove depth to polishing layer thickness. Specifically, in Examples 1 to 3, although the compressibility of the polishing layer, the thickness of the polishing layer, and the thickness of the polishing pad were substantially the same, the grooves had different depths, resulting in different groove depths relative to the thickness of the polishing layer, and thus different polishing rates on the wafer were observed during the polishing process.

[0150] Therefore, by adjusting the compression ratio of the polishing layer and / or the depth of the groove relative to the thickness of the polishing pad, the polishing pad can have excellent physical properties, and desired polishing characteristics can be provided in the polishing process. [Explanation of symbols]

[0151] 100: Polishing pad 110: Polishing layer 115, 215: Groove 120, 220: Adhesive layer 130, 230: Cushion layer 200: Recycled polishing pad 210: Reusable polishing layer

Claims

1. The step of recovering the polishing layer from the polishing pad used in the CMP process, The steps include flattening one surface of the polished layer, The steps include: forming grooves on one surface of the flattened polishing layer to produce a reusable polishing layer; The step includes attaching a cushion layer to the other surface of the reused polishing layer using an adhesive, The compressibility of the reused polishing layer calculated using the following formula 1 is 0.9% or more. A method for manufacturing a recycled polishing pad having a structure in which the cushion layer, the adhesive layer, and the reuse polishing layer are sequentially in contact and laminated: [Formula 1] In the above formula 1, T1 is the thickness (mm) of the reused polishing layer measured by applying pressure to the reused polishing layer with a load of 85g for 30 seconds, and the compression ratio of the reused polishing layer is the compression ratio of the reused polishing layer in a 25mm x 25mm area. T2 is the thickness (mm) of the reused polishing layer, measured after applying an additional load of 885g for 3 minutes following the measurement of T1.

2. The method for manufacturing a recycled polishing pad according to claim 1, wherein, in the step of forming the groove, the groove is formed to have a depth of 0.7 times or less the thickness of the reused polishing layer.

3. The step of recovering the polishing layer includes selecting from the polishing layers obtained from the polishing pad used in the CMP process a polishing layer with a compression ratio of 0.9% or more calculated by the following formula 3, the method for manufacturing a recycled polishing pad according to claim 1: [Formula 3] In the above formula 3, the compression ratio of the polishing layer is the compression ratio of the polishing layer with dimensions of 25 mm x 25 mm in both length and width. T5 is the thickness (mm) of the polishing layer measured by applying pressure to the polishing layer with a load of 85g for 30 seconds. T6 is the thickness (mm) of the polishing layer measured after applying an additional load of 885g to the polishing layer for 3 minutes after measuring T5.

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