A processing method of water-based high-efficiency CMP polishing pad

Abstract

The application relates to the technical field of polishing materials, and particularly discloses a processing method of a water-based high-efficiency CMP polishing pad. The processing method of the water-based high-efficiency CMP polishing pad comprises the following steps: immersing non-woven fabric in dipping material A, performing first extrusion, taking out the non-woven fabric, immersing the non-woven fabric in the dipping material A again, performing second extrusion again, taking out the non-woven fabric, drying, polishing, and obtaining pretreated non-woven fabric; the dipping material A comprises 80-120 parts of deionized water, 80-120 parts of resin A, 1-5 parts of a thickening agent and 1-5 parts of water-based color paste; the pretreated non-woven fabric is immersed in dipping material B, third extrusion is performed, the pretreated non-woven fabric is taken out, the pretreated non-woven fabric is immersed in the dipping material B again, fourth extrusion is performed again, the pretreated non-woven fabric is taken out, dried, polished, and a CMP polishing pad is obtained; the dipping material B comprises 180-220 parts of deionized water, 80-120 parts of resin B, 1-5 parts of water-based color paste and 1-5 parts of a crosslinking agent.

Description

Technical Field

[0001] This application relates to the technical field of polishing materials, and in particular to a method for processing a water-based high-efficiency CMP polishing pad. Background Technology

[0002] CMP polishing pads are primarily used in semiconductor, sapphire, metal, and ceramic industries. Composed of polyurethane or a polyurethane-based composite material, the pad's surface has micro-protrusions that directly contact the workpiece, generating friction. Under centrifugal force, the polishing layer is mechanically removed. Simultaneously, polishing fluid is evenly sprayed onto the pad's surface, chemically removing the polishing layer and carrying the reaction products out of the pad. The properties of the polishing pad directly affect the surface quality of the workpiece and are a direct factor influencing the planarization effect.

[0003] Polishing pads are one of the essential consumables in CMP polishing processes, and they have high requirements for cutting rate and service life. Currently, the commonly used polishing pads are made by thoroughly stirring solvent, polyurethane resin, toner, and additives to form a viscous liquid, which is then coated on the surface of non-woven fabric and solidified. Although these polishing pads can achieve the polishing effect, they have poor durability and short service life. Summary of the Invention

[0004] To improve the durability of the polishing pad, this application provides a method for processing a water-based high-efficiency CMP polishing pad.

[0005] This application provides a processing method for a water-based high-efficiency CMP polishing pad, which adopts the following technical solution:

[0006] A method for processing a water-based high-efficiency CMP polishing pad includes the following steps:

[0007] Pre-impregnation: The nonwoven fabric is impregnated in impregnation material A in impregnation tank one, subjected to the first compression, and the nonwoven fabric is removed. It is then impregnated again in impregnation material A in impregnation tank two, subjected to the second compression, removed, dried, and polished to obtain the pre-treated nonwoven fabric. The raw material of impregnation material A includes the following components in parts by weight: 80-120 parts of deionized water, 80-120 parts of resin A, 1-5 parts of thickener, and 1-5 parts of water-based color paste.

[0008] Impregnation: The pretreated nonwoven fabric is impregnated in impregnation material B in impregnation tank one, and subjected to a third extrusion. The pretreated nonwoven fabric is then removed and impregnated again in impregnation material B in impregnation tank two, and subjected to a fourth extrusion. After removal, drying, and polishing, a CMP polishing pad is obtained. The raw material of impregnation material B includes the following components in parts by weight: 180-220 parts of deionized water, 80-120 parts of resin B, 1-5 parts of water-based color paste, and 1-5 parts of crosslinking agent.

[0009] By adopting the above technical solution, the nonwoven fabric is impregnated twice in impregnation material A, then dried and polished. Then it is impregnated twice more in impregnation material B, and then dried and polished again. The resulting CMP polishing pad has low polishing loss and high durability. It also has high hardness and high polishing efficiency. In addition, it has low compression ratio and moderate compression elasticity. The polishing pad has a large range of uniform contact with the workpiece, ensuring the uniformity of the polished surface of the workpiece.

[0010] In one specific implementation, resin A comprises polyurethane UA3221 with a solid content of 40-43%; and resin B comprises polyurethane UA3055 with a solid content of 40-43%.

[0011] In one specific implementation, the aqueous pigment comprises a mixture of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water.

[0012] In one specific embodiment, the crosslinking agent comprises trimethylolpropane-tris[3-(2-methylacridinyl)propionate].

[0013] In one specific implementation, the first extrusion, the second extrusion, the third extrusion, and the fourth extrusion are all performed under a weight of 2.5-3.5 kg, and the extrusion gap is 1-1.4 mm.

[0014] By adopting the above technical solution, utilizing two different types of polyurethane, and further limiting the extrusion weight and extrusion gap, the performance of the polishing pad can be improved.

[0015] In one specific implementation, in the impregnation step, the dried pre-treated nonwoven fabric is first polished with 140-160 grit sandpaper, and then polished a second time with 110-130 grit sandpaper to obtain a CMP polishing pad.

[0016] By adopting the above technical solution, high-grit sandpaper is first used for preliminary polishing, and then low-grit sandpaper is used for further polishing. This results in a high surface roughness of the polishing pad, a small contact area between the polishing pad and the workpiece, and the ability to store more polishing fluid. Therefore, the effect rate on a single particle is greater, thus improving polishing efficiency.

[0017] In one specific implementation, the raw material of the impregnating material B further includes 5 to 10 parts by weight of filler, wherein the raw material of the filler includes ethanol, γ-aminopropyltriethoxysilane, nano zinc oxide, and nano silica.

[0018] In one specific implementation, the method for preparing the filler includes the following steps:

[0019] Ethanol, γ-aminopropyltriethoxysilane, and water were stirred and mixed evenly to obtain a modified solution. Nano zinc oxide and nano silica were added to a mixer and stirred. During the stirring process, the modified solution was sprayed onto the nano zinc oxide and nano silica. After spraying, stirring was continued, and then the mixture was dried to obtain the filler.

[0020] By adopting the above technical solution, γ-aminopropyltriethoxysilane is first dissolved in ethanol to obtain a modified liquid, which is then sprayed onto nano zinc oxide and nano silica. After drying, the ethanol is removed, allowing γ-aminopropyltriethoxysilane to coat the nano zinc oxide and nano silica, thus improving the dispersion performance of the nano zinc oxide and nano silica. This results in the nano zinc oxide and nano silica being uniformly dispersed in the impregnating material B. The combination of nano zinc oxide and nano silica further improves the wear resistance of the polishing pad.

[0021] In one specific implementation, the weight ratio of the modified liquid to the mixture of the nano zinc oxide and the nano silica is 1:(13-14).

[0022] By adopting the above technical solution, the ratio of the modifying liquid to nano zinc oxide and nano silica is further limited, so that the modifying liquid can be uniformly coated on the nano zinc oxide and nano silica, thereby improving the modification effect of nano zinc oxide and nano silica.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. In this application, the nonwoven fabric is impregnated twice in impregnation material A, then dried and polished. Then it is impregnated twice more in impregnation material B, then dried and polished again. The resulting CMP polishing pad has low polishing loss and high durability. It also has high hardness and high polishing efficiency. In addition, it has low compression ratio and moderate compression elasticity. The polishing pad has a large range of uniform contact with the workpiece, ensuring the uniformity of the polished surface of the workpiece.

[0025] 2. In this application, high-grit sandpaper is first used for preliminary polishing, and then low-grit sandpaper is used for further polishing. This results in a high surface roughness of the polishing pad, a small contact area between the polishing pad and the workpiece, and the ability to store more polishing fluid. Therefore, the effect rate on a single particle is greater, thus improving the polishing efficiency.

[0026] 3. In this application, γ-aminopropyltriethoxysilane-modified nano-zinc oxide and nano-silica are added to the impregnation material B. The combination of nano-zinc oxide and nano-silica further improves the wear resistance of the polishing pad. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments.

[0028] All raw materials used in the examples are commercially available. The polyurethane UA3221 is designated as UA3221; the polyurethane UA3055 as UA3055; and the thickener is designated as T010.

[0029] Preparation Example

[0030] Preparation Example 1

[0031] Preparation Example 1 provides a method for preparing a packing material, comprising the following steps:

[0032] Ethanol, γ-aminopropyltriethoxysilane, and water were stirred and mixed evenly to obtain a modified solution. Nano zinc oxide and nano silica were added to a mixer and stirred. During the stirring process, the modified solution was sprayed onto the nano zinc oxide and nano silica. After spraying, stirring was continued for 0.5 hours, and then dried at 115℃ for 1.5 hours to obtain the filler. The weight ratio of ethanol, γ-aminopropyltriethoxysilane, and water was 18:5:2; the weight ratio of nano zinc oxide and nano silica was 1:3; and the weight ratio of the modified solution to the mixture of nano zinc oxide and nano silica was 1:12.5.

[0033] Preparation Example 2

[0034] The difference between Preparation Example 2 and Preparation Example 1 is that the weight ratio of the modified liquid to the mixture of nano zinc oxide and nano silica is 1:13; the remaining steps are the same as those in Preparation Example 1.

[0035] Preparation Example 3

[0036] The difference between Preparation Example 3 and Preparation Example 1 is that the weight ratio of the modified liquid to the mixture of nano zinc oxide and nano silica is 1:13.5; the remaining steps are the same as those in Preparation Example 1.

[0037] Preparation Example 4

[0038] The difference between Preparation Example 4 and Preparation Example 1 is that the weight ratio of the modified liquid to the mixture of nano zinc oxide and nano silica is 1:14; the remaining steps are the same as in Preparation Example 1.

[0039] Preparation Example 5

[0040] The difference between Preparation Example 5 and Preparation Example 1 is that the weight ratio of the modified liquid to the mixture of nano zinc oxide and nano silica is 1:14.5; the remaining steps are the same as those in Preparation Example 1.

[0041] Example

[0042] Example 1

[0043] Example 1 provides a method for processing a water-based high-efficiency CMP polishing pad, comprising the following steps:

[0044] Pre-impregnation: Mix 80kg of deionized water, 80kg of resin A, 1kg of thickener, and 1kg of water-based color paste evenly to obtain impregnating material A; wherein resin A is polyurethane UA3221 with a solid content of 40-43%; the water-based color paste is a mixture of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water, and the weight ratio of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water is 5:3:12.

[0045] The nonwoven fabric is immersed in immersion material A in immersion tank one and subjected to a first compression under a weight of 2.5 kg with a compression gap of 1 mm. The nonwoven fabric is then removed and immersed again in immersion material A in immersion tank two, and subjected to a second compression under a weight of 2.5 kg with a compression gap of 1 mm. After drying, it is polished with 150-grit sandpaper to obtain a pretreated nonwoven fabric. The nonwoven fabric is a pure polyester nonwoven fabric.

[0046] Impregnation: 180 kg of deionized water, 80 kg of resin B, 1 kg of water-based color paste, and 1 kg of crosslinking agent are stirred and mixed evenly to obtain impregnating material B; wherein resin B is polyurethane UA3055 with a solid content of 40-43%; the water-based color paste is a mixture of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water, and the weight ratio of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water is 5:3:12; the crosslinking agent is trimethylolpropane-tris[3-(2-methylacridinyl)propionate].

[0047] The pretreated nonwoven fabric is immersed in immersion material B in immersion tank one and subjected to a third compression under a weight of 2.5 kg with a compression gap of 1 mm. The pretreated nonwoven fabric is then removed and immersed again in immersion material B in immersion tank two, and subjected to a fourth compression under a weight of 2.5 kg with a compression gap of 1 mm. After drying, it is first polished with 150-grit sandpaper and then polished a second time with 120-grit sandpaper to obtain a CMP polishing pad.

[0048] Example 2

[0049] The difference between Example 2 and Example 1 is that the nonwoven fabric is immersed in the immersion material A in the first immersion tank and subjected to the first compression under a weight of 3 kg with a compression gap of 1.2 mm. The nonwoven fabric is then removed and immersed again in the immersion material A in the second immersion tank, and subjected to the second compression under a weight of 3 kg with a compression gap of 1.2 mm. After drying, it is polished with 150-grit sandpaper to obtain the pretreated nonwoven fabric.

[0050] The pretreated nonwoven fabric is immersed in immersion material B in immersion tank one, and subjected to a third compression under a weight of 3 kg with a compression gap of 1.2 mm. The pretreated nonwoven fabric is then removed and immersed again in immersion material B in immersion tank two, and subjected to a fourth compression under a weight of 3 kg with a compression gap of 1.2 mm. After drying, it is first polished with 150-grit sandpaper, and then polished a second time with 120-grit sandpaper to obtain a CMP polishing pad. The remaining steps are consistent with those in Example 1.

[0051] Example 3

[0052] The difference between Example 3 and Example 1 is that the nonwoven fabric is immersed in the immersion material A in the first immersion tank and subjected to the first compression under a weight of 3.5 kg with a compression gap of 1.4 mm. The nonwoven fabric is then removed and immersed again in the immersion material A in the second immersion tank, and subjected to the second compression under a weight of 3.5 kg with a compression gap of 1.4 mm. After drying, it is polished with 150-grit sandpaper to obtain the pretreated nonwoven fabric.

[0053] The pretreated nonwoven fabric is immersed in immersion material B in immersion tank one and subjected to a third compression under a weight of 3.5 kg with a compression gap of 1.4 mm. The pretreated nonwoven fabric is then removed and immersed again in immersion material B in immersion tank two, and subjected to a fourth compression under a weight of 3.5 kg with a compression gap of 1.4 mm. After drying, it is first polished with 150-grit sandpaper and then polished a second time with 120-grit sandpaper to obtain a CMP polishing pad. The remaining steps are consistent with those in Example 1.

[0054] Example 4

[0055] The difference between Example 4 and Example 2 is that 100 kg of deionized water, 100 kg of resin A, 3 kg of thickener, and 3 kg of water-based color paste are stirred and mixed evenly to obtain impregnating material A;

[0056] 200 kg of deionized water, 100 kg of resin B, 3 kg of water-based pigment, and 3 kg of crosslinking agent were stirred and mixed evenly to obtain impregnating material B; the remaining steps were the same as in Example 2.

[0057] Example 5

[0058] The difference between Example 5 and Example 2 is that 120 kg of deionized water, 120 kg of resin A, 5 kg of thickener, and 5 kg of water-based color paste are stirred and mixed evenly to obtain impregnating material A;

[0059] 220 kg of deionized water, 120 kg of resin B, 5 kg of water-based pigment, and 5 kg of crosslinking agent were stirred and mixed evenly to obtain impregnating material B; the remaining steps were the same as in Example 2.

[0060] Example 6

[0061] The difference between Example 6 and Example 4 is that the mixture consisting of 200 kg of deionized water, 100 kg of resin B, 3 kg of water-based pigment, 3 kg of crosslinking agent, 8 kg of nano zinc oxide, and nano silica is stirred and mixed evenly to obtain impregnating material B; wherein the weight ratio of nano zinc oxide to nano silica is 1:3; the remaining steps are the same as in Example 4.

[0062] Example 7

[0063] The difference between Example 7 and Example 4 is that 200 kg of deionized water, 100 kg of resin B, 3 kg of water-based pigment, 3 kg of crosslinking agent, and 8 kg of filler from Preparation Example 1 are stirred and mixed evenly to obtain impregnating material B; the remaining steps are the same as in Example 4.

[0064] Example 8

[0065] The difference between Example 8 and Example 4 is that 200 kg of deionized water, 100 kg of resin B, 3 kg of water-based pigment, 3 kg of crosslinking agent, and 8 kg of filler from Preparation Example 2 are stirred and mixed evenly to obtain impregnating material B; the remaining steps are the same as in Example 4.

[0066] Example 9

[0067] The difference between Example 9 and Example 4 is that 200 kg of deionized water, 100 kg of resin B, 3 kg of water-based pigment, 3 kg of crosslinking agent, and 8 kg of filler from Preparation Example 3 are stirred and mixed evenly to obtain impregnating material B; the remaining steps are the same as in Example 4.

[0068] Example 10

[0069] The difference between Example 10 and Example 4 is that 200 kg of deionized water, 100 kg of resin B, 3 kg of water-based pigment, 3 kg of crosslinking agent, and 8 kg of filler from Example 4 are stirred and mixed evenly to obtain impregnating material B; the remaining steps are the same as in Example 4.

[0070] Example 11

[0071] The difference between Example 11 and Example 4 is that 200 kg of deionized water, 100 kg of resin B, 3 kg of water-based pigment, 3 kg of crosslinking agent, and 8 kg of filler from Preparation Example 5 are stirred and mixed evenly to obtain impregnating material B; the remaining steps are the same as in Example 4.

[0072] Comparative Example

[0073] Comparative Example 1

[0074] Comparative Example 1 provides a method for processing a CMP polishing pad, including the following steps:

[0075] Pre-impregnation: Mix 80kg of deionized water, 80kg of resin A, 1kg of thickener, and 1kg of water-based color paste evenly to obtain impregnating material A; wherein resin A is polyurethane UA3221 with a solid content of 40-43%; the water-based color paste is a mixture of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water, and the weight ratio of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water is 5:3:12.

[0076] The nonwoven fabric is impregnated in impregnating material A and extruded under a weight of 2.5 kg with an extrusion gap of 1 mm. The nonwoven fabric is then removed, dried, and polished with 150-grit sandpaper to obtain a pre-treated nonwoven fabric. The nonwoven fabric is made of pure polyester.

[0077] Impregnation: 180 kg of deionized water, 80 kg of resin B, 1 kg of water-based color paste, and 1 kg of crosslinking agent are stirred and mixed evenly to obtain impregnating material B; wherein resin B is polyurethane UA3055 with a solid content of 40-43%; the water-based color paste is a mixture of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water, and the weight ratio of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water is 5:3:12; the crosslinking agent is trimethylolpropane-tris[3-(2-methylacridinyl)propionate].

[0078] The pretreated nonwoven fabric is immersed in impregnating material B and extruded under a weight of 2.5 kg with an extrusion gap of 1 mm. The pretreated nonwoven fabric is then removed, dried, and first polished with 150 grit sandpaper, and then polished a second time with 120 grit sandpaper to obtain a CMP polishing pad.

[0079] Comparative Example 2

[0080] Comparative Example 2 provides a method for processing a CMP polishing pad, including the following steps:

[0081] 80 kg of deionized water, 80 kg of polyurethane resin, 1 kg of thickener, 1 kg of water-based color paste, and 1 kg of crosslinking agent were stirred and mixed evenly to obtain the impregnation material; wherein the water-based color paste is a mixture of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water, and the weight ratio of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water is 5:3:12; the crosslinking agent is trimethylolpropane-tris[3-(2-methylacridinyl)propionate]; the nonwoven fabric is all-polyester nonwoven fabric;

[0082] The non-woven fabric is impregnated in the impregnating material and squeezed under a weight of 2.5 kg with a squeezing gap of 1 mm. The non-woven fabric is then removed, dried, and polished with 150-grit sandpaper to obtain a CMP polishing pad.

[0083] Performance testing

[0084] 1. Hardness: The polishing pad was tested using a Shore A hardness tester to obtain the Shore A hardness.

[0085] 2. Wear resistance: Using a Table wear tester, with a load of 1kg, grind for 5000 cycles, test the weight A before grinding and the weight B after grinding, and calculate the wear mass C = AB. The smaller the wear mass, the better the wear resistance of the polishing pad.

[0086] Table 1 Performance test results of polishing pads

[0087] sample Hardness (°) Loss of mass C (mg) Example 1 80 108.2 Example 2 81 105.8 Example 3 81 106.2 Example 4 81 105.3 Example 5 82 105.5 Example 6 85 104.3 Example 7 86 102.0 Example 8 87 100.5 Example 9 87 100.2 Example 10 86 100.7 Example 11 86 102.9 Comparative Example 1 75 115.2 Comparative Example 2 73 119.5

[0088] Combining Example 1 and Comparative Examples 1-2, the polishing pad in Example 1 has higher hardness and better wear resistance. It can be seen that by using the non-woven fabric processing method in this application, the non-woven fabric is first impregnated twice in impregnation material A, then dried and polished, and then impregnated twice more in impregnation material B, and then dried and polished again. The resulting CMP polishing pad has better wear resistance, thereby improving the durability of the polishing pad.

[0089] In combination with Examples 1-3, the polishing pad in Example 2 has the lowest wear mass, thus the polishing pad in Example 2 has the best wear resistance. It can be seen that the extrusion conditions of the nonwoven fabric in Example 2 are optimal, thereby improving the durability of the polishing pad.

[0090] Combining Examples 2, 4, and 5, the hardness and wear mass of the polishing pads in Examples 2, 4, and 5 are not significantly different. This indicates that increasing the amount of raw materials used in preparing impregnating material A and impregnating material B has little impact on the performance of the resulting nonwoven fabric.

[0091] Combining Examples 4, 6, and 7, the polishing pad in Example 7 has higher hardness and lower wear mass. This shows that when preparing impregnation material B, adding γ-aminopropyltriethoxysilane-modified nano zinc oxide and nano silica to the raw materials can improve the wear resistance of the polishing pad by utilizing the combination of nano zinc oxide and nano silica.

[0092] In conjunction with Examples 7-11, the polishing pads in Examples 8-10 exhibit higher hardness. This indicates that when preparing the γ-aminopropyltriethoxysilane-modified filler, the preferred ratio of the modified liquid to the mixture of nano zinc oxide and nano silica is 1:(13-14). This results in a better modification effect of the filler, thereby improving the wear resistance of the final polishing pad. This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for processing a water-based high-efficiency CMP polishing pad, characterized in that: Includes the following steps: Pre-impregnation: The nonwoven fabric is impregnated in impregnation material A in impregnation tank one, subjected to the first compression, and the nonwoven fabric is removed. It is then impregnated again in impregnation material A in impregnation tank two, subjected to the second compression, removed, dried, and polished to obtain the pretreated nonwoven fabric. The raw material A includes the following components by weight: 80-120 parts deionized water, 80-120 parts resin A, 1-5 parts thickener, and 1-5 parts water-based color paste. The water-based color paste is a mixture of acetylene black, fatty alcohol polyoxyethylene ether, and deionized water. Impregnation: The pretreated nonwoven fabric is impregnated in impregnation material B in impregnation tank one, and subjected to a third extrusion. The pretreated nonwoven fabric is then removed and impregnated again in impregnation material B in impregnation tank two, and subjected to a fourth extrusion. After removal and drying, the dried pretreated nonwoven fabric is first polished with 140-160 grit sandpaper, and then polished a second time with 110-130 grit sandpaper to obtain a CMP polishing pad. The raw materials of impregnation material B include the following components in parts by weight: 180-220 parts of deionized water, 80-120 parts of resin B, 1-5 parts of water-based pigment, 1-5 parts of crosslinking agent, and 5-10 parts of filler. The raw materials of the filler include ethanol, γ-aminopropyltriethoxysilane, nano zinc oxide, and nano silica. The preparation method of the filler includes the following steps: ethanol, γ-aminopropyltriethoxysilane, and water are stirred and mixed evenly to obtain a modified liquid. Nano zinc oxide and nano silica are added to a mixer and stirred. During stirring, the modified liquid is sprayed onto the nano zinc oxide and nano silica. After spraying, stirring continues, and then the mixture is dried to obtain the filler. The crosslinking agent includes trimethylolpropane-tris[3-(2-methylacridinyl)propionate]. The first extrusion, the second extrusion, the third extrusion, and the fourth extrusion are all performed at a weight of 2.5-3.5 kg, and the extrusion gap is 1-1.4 mm. The weight ratio of the modified liquid to the mixture of nano zinc oxide and nano silica is 1:(13-14).