A novel polishing pad and a method of manufacturing the same

Abstract

The application relates to the technical field of electronic chemical material processing, and particularly discloses a novel polishing pad and a manufacturing method thereof. The novel polishing pad comprises a non-woven fabric layer and an impregnated resin layer covering the surface of the non-woven fabric layer, the impregnated resin layer is obtained by polishing a solidified product of impregnated slurry, and the impregnated slurry comprises the following components in parts by weight: 90-94 parts of an aqueous resin, 4-6 parts of carboxyl-modified quartz powder and 14.4-14.8 parts of polycarbodiimide, wherein the carboxyl-modified quartz powder is quartz powder with grafted carboxyl on the surface. When the novel polishing pad is used to polish a workpiece, the wear degree of the impregnated resin layer is relatively small, which helps to maintain good polishing effect of the polishing pad for a long time and prolongs the service life of the polishing pad.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic chemical material processing, and more particularly to a novel polishing pad and a manufacturing method thereof. BACKGROUND

[0002] At present, in the processing of electronic chemical materials, a polishing step is usually included, and a polishing pad is required in the polishing step. For example, in chemical mechanical polishing, the polishing pad has the functions of storing polishing liquid, conveying polishing liquid, discharging waste, transmitting processing load, and ensuring smooth polishing process, and the performance of the polishing pad has a significant impact on the polishing effect.

[0003] In the related art, a polishing pad includes a non-woven fabric layer and an impregnated resin layer covering the surface of the non-woven fabric layer, and is prepared by the following method: (1) weaving polymer fibers into a web, and then performing needle punching to obtain the non-woven fabric layer; (2) applying water-based resin as impregnated slurry to the surface of the non-woven fabric layer, and then drying to solidify the impregnated slurry on the surface of the non-woven fabric layer; and (3) polishing the solidified product of the impregnated slurry to obtain the novel polishing pad.

[0004] In view of the above related art, the inventors believe that in the process of polishing a workpiece, the impregnated resin layer on the surface of the polishing pad will be subjected to frequent friction, and the solidified product of the water-based resin has limited wear resistance. Long-term friction will cause significant wear of the impregnated resin layer, resulting in a decrease in the polishing effect of the polishing pad on the workpiece. SUMMARY

[0005] In the related art, long-term friction will cause significant wear of the impregnated resin layer, resulting in a decrease in the polishing effect of the polishing pad on the workpiece. In order to improve this defect, the present application provides a novel polishing pad and a manufacturing method thereof.

[0006] In a first aspect, the present application provides a novel polishing pad, which adopts the following technical solution:

[0007] A novel polishing pad includes a non-woven fabric layer and an impregnated resin layer covering the surface of the non-woven fabric layer, the impregnated resin layer being obtained by polishing the solidified product of impregnated slurry, the impregnated slurry including the following components by weight: 90-94 parts of water-based resin, 4-6 parts of carboxyl-modified quartz powder, and 14.4-14.8 parts of polycarbodiimide, the carboxyl-modified quartz powder being quartz powder with carboxyl groups grafted on the surface.

[0008] By adopting the technical scheme, the modified quartz powder and the polycarbodiimide are added to the water-based resin to obtain new impregnation slurry. After the impregnation slurry is solidified into an impregnated resin layer, the polycarbodiimide reacts with the carboxyl groups on the surface of the carboxyl-modified quartz powder to form an acylurea bond, so that the modified quartz powder distributed in the impregnated resin layer is connected to each other to form a network structure. The network structure improves the wear resistance of the impregnated resin layer, and the carboxyl-modified quartz powder is a rigid particle and can toughen the impregnated resin layer. Therefore, when the new polishing pad of the application is used to polish a workpiece, the wear degree of the impregnated resin layer is relatively small, which helps to maintain good polishing effect of the polishing pad for a long time and prolong the service life of the polishing pad.

[0009] Preferably, the water-based resin is one of a water-based polyurethane resin, a water-based acrylic resin and a water-based polyurethane-acrylic copolymer resin.

[0010] By adopting the technical scheme, the types of the water-based resin are preferred. The water-based acrylic resin, the water-based polyurethane resin and the water-based polyurethane-acrylic copolymer resin all have a certain amount of carboxyl groups. After the impregnation slurry prepared by using the water-based resin is solidified, the carboxyl groups of the water-based resin and the carboxyl groups of the carboxyl-modified quartz powder can react with the polycarbodiimide, thereby realizing the indirect combination between the water-based resin solidification and the carboxyl-modified quartz powder. The carboxyl-modified quartz powder and the modified quartz powder are connected to each other to form a network structure, which helps to fix the carboxyl-modified quartz powder and improve the wear resistance of the polishing pad.

[0011] Preferably, the water-based resin is a water-based polyurethane-acrylic copolymer resin.

[0012] By adopting the technical scheme, the type of the water-based resin is preferred, which helps to reduce the wear of the polishing pad and improve the wear resistance of the polishing pad.

[0013] Preferably, the carboxyl-modified quartz powder is prepared by the following method:

[0014] (1) The amino-modified quartz powder and the trimellitic anhydride are added to tetrahydrofuran and stirred to obtain a reaction solution; the amino-modified quartz powder is quartz powder with amino groups grafted on the surface;

[0015] (2) The reaction solution is stirred for 8-10 hours, and then the reaction solution is centrifuged to obtain the carboxyl-modified quartz powder after washing the obtained precipitate until the waste water is neutral.

[0016] By adopting the technical scheme, the amino-modified quartz powder is modified by trimellitic anhydride. The acid anhydride groups in the trimellitic anhydride can react with the amino groups to form an amide bond, and a carboxyl group is generated at the ortho position, thereby obtaining the carboxyl-modified quartz powder.

[0017] As preferred, the amino-modified quartz powder is prepared according to the following method:

[0018] (1) mixing γ-aminopropyl triethoxysilane, water and ethanol to obtain a silane modification liquid; adding quartz powder into the aqueous dispersant, and stirring to obtain a quartz impregnation liquid; the amount of the γ-aminopropyl triethoxysilane is 6-8% of the weight of the quartz powder;

[0019] (2) mixing the silane modification liquid and the quartz impregnation liquid, and after stirring and heating, filtering, washing and drying the obtained solid to obtain the amino-modified quartz powder.

[0020] By using the above technical solution, the γ-aminopropyl triethoxysilane is used to couple and modify the quartz powder, and the amino group is grafted onto the surface of the quartz powder to obtain the amino-modified quartz powder.

[0021] As preferred, the molar ratio of the trimellitic anhydride to the γ-aminopropyl triethoxysilane is (1.25-1.35):1.

[0022] By using the above technical solution, the molar ratio of the trimellitic anhydride to the amino-silane coupling agent is preferred, and by making the trimellitic anhydride relatively excessive, it is helpful to make the reaction of the anhydride and the amino group more complete.

[0023] As preferred, the aqueous dispersant is silica sol.

[0024] By using the above technical solution, the silica sol can increase the number of silicon hydroxyl groups on the surface of the quartz powder, so that after the treatment of the quartz powder by the silane modification liquid, more amino groups can be grafted on the surface, and after the reaction of the amino group and the trimellitic anhydride, the carboxyl-modified quartz powder with a higher total amount of carboxyl groups on the surface is obtained (compared with using pure water as the aqueous dispersant). Since the total amount of carboxyl groups on the surface of the carboxyl-modified quartz powder is increased, the network structure formed by the reaction of the modified quartz powder and the polycarbodiimide is more firm, which helps to improve the wear resistance of the polishing pad.

[0025] As preferred, in step (1) of preparing the amino-modified quartz powder, halloysite nanotubes and quartz powder are added into the aqueous dispersant together.

[0026] By using the above technical solution, in the quartz impregnation liquid, the silica sol can adhere the halloysite nanotubes to the surface of the quartz powder, and the halloysite nanotubes can increase the surface area of the quartz powder, which helps to increase the total amount of grafted amino groups on the surface of the quartz powder, and obtain the carboxyl-modified quartz powder with a higher total amount of carboxyl groups on the surface, thereby improving the wear resistance of the polishing pad.

[0027] As preferred, the amount of the halloysite nanotubes is 5-8% of the weight of the quartz powder.

[0028] By adopting the technical scheme, the amount of the halloysite nanotubes is preferably selected, which helps to improve the wear resistance of the polishing pad and save the amount of the halloysite nanotubes.

[0029] In a second aspect, the application provides a manufacturing method of the novel polishing pad, which adopts the following technical scheme.

[0030] The manufacturing method of the novel polishing pad comprises the following steps.

[0031] (1) weaving polymer fibers into a net, and then performing needle punching to obtain a non-woven fabric layer;

[0032] (2) mixing the water-based resin, the modified quartz powder and the polycarbodiimide to obtain impregnation slurry, coating the impregnation slurry on the surface of the non-woven fabric layer, and then performing drying to solidify the impregnation slurry on the surface of the non-woven fabric layer;

[0033] (3) polishing the solidification product of the impregnation slurry to obtain the novel polishing pad.

[0034] By adopting the technical scheme, the manufacturing method of the application first prepares the non-woven fabric layer, then coats the impregnation slurry on the surface of the non-woven fabric layer, and finally obtains the novel polishing pad after drying and solidification and polishing.

[0035] In summary, the application has the following beneficial effects:

[0036] 1. The modified quartz powder and the polycarbodiimide are added to the water-based resin to obtain new impregnation slurry, and the wear resistance of the impregnated resin layer is improved through the crosslinking of the modified quartz powder and the polycarbodiimide. When the novel polishing pad of the application is used to polish workpieces, the wear degree of the impregnated resin layer is relatively small, which helps to maintain good polishing effect of the polishing pad for a long time and prolong the service life of the polishing pad.

[0037] 2. The water-based dispersant is preferably silica sol, which helps to increase the carboxyl content on the surface of the carboxyl modified quartz powder, so that the network structure formed by the reaction of the modified quartz powder and the polycarbodiimide is more firm, which helps to improve the wear resistance of the polishing pad. DETAILED DESCRIPTION

[0038] The application will be further described in detail below in combination with examples, preparation examples and comparative examples. The raw materials involved in the application can be obtained by market purchase.

[0039] Preparation example of carboxyl modified quartz powder

[0040] The following will be described taking preparation example 1 as an example.

[0041] Preparation example 1

[0042] Before the preparation of the carboxyl-modified quartz powder, an amino-modified quartz powder is prepared according to the following method: (1) γ-aminopropyl triethoxysilane, water and ethanol are mixed according to a weight ratio of 1:3:6 to obtain a silane-modified liquid; quartz powder is added into the aqueous dispersant, and stirred for 30 min to obtain a quartz impregnation liquid; in this step, the aqueous dispersant is pure water, the weight ratio of the quartz powder to the aqueous dispersant is 1:2, the average particle size of the quartz powder is 80 μm, and the amount of the γ-aminopropyl triethoxysilane is 6% of the weight of the quartz powder;

[0043] (2) The silane-modified liquid and the quartz impregnation liquid are mixed, stirred at 25°C for 5 h, and then centrifuged and filtered; the obtained solid is washed twice with ethanol, acetone and tetrahydrofuran in sequence, and then dried at 50°C to obtain the amino-modified quartz powder.

[0044] In this preparation example, the carboxyl-modified quartz powder is prepared according to the following method:

[0045] (1) The amino-modified quartz powder and trimellitic anhydride are added into tetrahydrofuran and stirred to mix (prepared according to a proportion of 1 g of trimellitic anhydride mixed with 0.25 L of tetrahydrofuran); a reaction liquid is obtained; the molar ratio of the trimellitic anhydride to the γ-aminopropyl triethoxysilane used in step (1) for preparing the amino-modified quartz powder is 1.25:1.

[0046] (2) The reaction liquid is stirred at 25°C for 8 h, and then centrifuged; after washing the obtained precipitate with water until the waste water eluted is neutral, a carboxyl-modified quartz powder is obtained.

[0047] Preparation Example 2

[0048] The difference between this preparation example and Preparation Example 1 is that the amount of the γ-aminopropyl triethoxysilane is 7% of the weight of the quartz powder.

[0049] Preparation Example 3

[0050] The difference between this preparation example and Preparation Example 1 is that the amount of the γ-aminopropyl triethoxysilane is 8% of the weight of the quartz powder.

[0051] Preparation Example 4

[0052] The difference between this preparation example and Preparation Example 3 is that the molar ratio of the trimellitic anhydride to the γ-aminopropyl triethoxysilane used in step (1) for preparing the amino-modified quartz powder is 1.30:1.

[0053] Preparation Example 5

[0054] The present preparation example differs from Preparation Example 3 in that the molar ratio of benzene tricarboxylic anhydride to γ-aminopropyl triethoxysilane used in step (1) of preparing the amino-modified quartz powder is 1.35:1.

[0055] Preparation Example 6

[0056] The present preparation example differs from Preparation Example 1 in that the aqueous dispersant is a silica sol with a water content of 85%.

[0057] Preparation Example 7

[0058] The present preparation example differs from Preparation Example 6 in that, in step (1) of preparing the amino-modified quartz powder, halloysite nanotubes and quartz powder are added together into the aqueous dispersant, and the amount of halloysite nanotubes is 4% by weight of the quartz powder.

[0059] As shown in Table 1, Preparation Examples 7-11 differ in that the amount of halloysite nanotubes is different, accounting for a percentage of the weight of the quartz powder (hereinafter referred to as the nanotube ratio).

[0060] Table 1 Nanotube Ratio

[0061] Sample Preparation Example 7 Preparation Example 8 Preparation Example 9 Preparation Example 10 Preparation Example 11 Nanotube fraction / % 4 5 6.5 8 9

[0062] Example

[0063] Examples 1-5

[0064] In the examples, the acid value of the aqueous polyurethane resin used is 45 mgKOH / g, the acid value of the aqueous acrylic resin is 42 mgKOH / g, and the acid value of the aqueous polyurethane-acrylic copolymer resin is 28 mgKOH / g. The following will be described by taking Example 1 as an example.

[0065] Example 1

[0066] The present example provides a new type of polishing pad, which comprises a non-woven fabric layer and an impregnated resin layer covering the surface of the non-woven fabric layer. The non-woven fabric layer is made of polyester fibers and has a thickness of 1.5 mm. The impregnated resin layer is obtained by curing an impregnated slurry. The components of the impregnated slurry are mixed from 90 kg of aqueous resin, 4 kg of carboxyl-modified quartz powder, and 14.4 kg of polymeric carbodiimide. The polymeric carbodiimide is a powder with an average particle size of 1.5 μm, an average polymerization degree of 22, and a number average molecular weight of 4414. The carboxyl-modified quartz powder is prepared according to Preparation Example 1.

[0067] In the present example, the new type of polishing pad is prepared according to the following steps:

[0068] (1) The polymer fibers are woven into a net and then needle punched to obtain a non-woven fabric layer. The polymer fibers are 100% polyester fibers.

[0069] (2) The aqueous resin, the modified quartz powder, and the polycarbodiimide were mixed to obtain an impregnation slurry, the impregnation slurry was coated on the surface of the nonwoven fabric layer by impregnation treatment, and then dried at 125°C to cure the impregnation slurry on the surface of the nonwoven fabric layer (sizing rate 12%); during the impregnation process, the pressure of the press roll was 3 MPa, and the impregnation temperature was 45°C;

[0070] (3) The cured product produced on the surface of the nonwoven fabric by the impregnation slurry was polished to obtain a new polishing pad having a surface roughness of 20 μm.

[0071] Table 2 shows that Examples 1-6 differ in the type of base material of the nonwoven material layer, the thickness of the nonwoven material layer, and the type of aqueous resin in the impregnation slurry.

[0072] Table 2 Nonwoven material layer base material type, thickness, and aqueous resin type in impregnation slurry

[0073]

[0074] Examples 7-10

[0075] Table 3 shows that Examples 7-10 differ from Example 6 in the formulation of the impregnation slurry.

[0076]

[0077] Examples 11-20

[0078] Table 3 shows that Examples 11-20 differ from Example 10 in that the carboxyl-modified quartz powder was prepared with reference to different preparation examples.

[0079] Table 3 Preparation examples referred to in preparation of carboxyl-modified quartz powder

[0080]

[0081]

[0082] Comparative Examples

[0083] Comparative Examples 1-6

[0084] Comparative Examples 1-6 differ from Examples 1-6 in that Comparative Examples 1-6 do not include the carboxyl-modified quartz powder and the polycarbodiimide in the impregnation slurry.

[0085] Comparative Example 7

[0086] This comparative example differs from Example 1 in that the carboxyl-modified quartz powder in the impregnation slurry was replaced with a quartz powder having an average particle diameter of 80 μm.

[0087] Comparative Example 8

[0088] The present comparative example differs from Example 1 in that the present comparative example removes the polycarbodiimide in the impregnation slurry.

[0089] Performance test method

[0090] The H-22 grinding wheel was assembled on the grinding wheel abrasion tester, and the polishing pad of each example and comparative example was subjected to abrasion test according to GB / T 1768-2006, "Determination of the Abrasion Resistance of Pigmented and Clear Coatings - Rotating Rubber Wheel Method". The grinding wheel was rotated 1000 times under a load of 1 kg, the average abrasion value of each group of samples was detected, and the results are shown in Table 4.

[0091] Table 4 Average abrasion value

[0092]

[0093]

[0094] It can be seen from Examples 1-6 and Comparative Examples 1-6 and Table 4 that the average abrasion value of the polishing pad increases significantly after removing the carboxyl modified quartz powder and polycarbodiimide in the impregnation slurry of Examples 1-6, indicating that the carboxyl modified quartz powder and polycarbodiimide can improve the abrasion resistance of the polishing pad when used together.

[0095] In Examples 1-3, the average abrasion value measured by Example 3 is smaller, in Examples 4-6, the average abrasion value measured by Example 6 is smaller, and the average abrasion value measured by Example 6 is lower than that of Example 3, indicating that the polishing pad with a water-based polyurethane-acrylic copolymer resin and a substrate composition of 80% PET and 20% PA has better abrasion resistance.

[0096] It can be seen from Examples 6-10 that the polishing pad of Example 10 has relatively good abrasion resistance in Examples 6-10.

[0097] It can be seen from Example 10 and Examples 11-14 and Table 4 that increasing the amount of γ-aminopropyl triethoxysilane does not significantly affect the average abrasion value, indicating that in Preparation Example 1, the surface of the quartz powder has been fully coupled with γ-aminopropyl triethoxysilane, and it is difficult to further increase the number of amino groups on the surface of the amino modified quartz powder by simply increasing the amount of silane coupling agent. Increasing the amount of trimellitic anhydride also does not significantly affect the average abrasion value, indicating that the amino groups in Example 10 have been fully reacted with trimellitic anhydride.

[0098] It can be seen from the combination of Example 10 and Example 15 and Table 4 that the average wear value measured in Example 15 is less than that in Example 10, indicating that the silica sol can increase the number of silicon hydroxyl groups on the surface of the quartz powder, so that the quartz powder treated by the silane modification liquid can graft more amino groups on the surface, and after the reaction of the amino groups with the trimellitic anhydride, the carboxyl-modified quartz powder with a higher total amount of carboxyl groups on the surface is obtained. Due to the increase in the total amount of carboxyl groups on the surface of the carboxyl-modified quartz powder, the network structure formed by the reaction of the modified quartz powder with the polycarbodiimide is more firm, which helps to improve the wear resistance of the polishing pad.

[0099] It can be seen from the combination of Example 15, Example 16-20 and Table 4 that in the quartz immersion liquid, the silica sol can adhere the halloysite nanotubes to the surface of the quartz powder, the halloysite nanotubes can increase the surface area of the quartz powder, which helps to increase the total amount of grafted amino groups on the surface of the quartz powder, and the carboxyl-modified quartz powder with a higher total amount of carboxyl groups on the surface is obtained, thereby improving the wear resistance of the polishing pad. When the amount of halloysite nanotubes is 5-8% by weight of the quartz powder, the wear resistance of the polishing pad can be improved sufficiently while saving the amount of halloysite nanotubes.

[0100] The specific embodiments are only an explanation of the present application, which is not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, as long as the modifications are within the scope of the claims of the present application.

Claims

1. A novel polishing pad, characterized in that, The novel polishing pad comprises a nonwoven fabric layer and an impregnated resin layer covering the surface of the nonwoven fabric layer. The impregnated resin layer is obtained by polishing the cured product of an impregnated slurry. The impregnated slurry comprises the following components in parts by weight: 90-94 parts of water-based resin, 4-6 parts of carboxyl-modified quartz powder, and 14.4-14.8 parts of polycarbodiimide. The carboxyl-modified quartz powder is quartz powder with carboxyl groups grafted onto its surface. The water-based resin is one of water-based polyurethane resin, water-based acrylic resin, and water-based polyurethane-acrylic copolymer resin. The carboxyl-modified quartz powder is prepared according to the following method: (1) Add amino-modified quartz powder and benzotriic anhydride to tetrahydrofuran and stir to obtain a reaction solution; the amino-modified quartz powder is quartz powder with amino groups grafted on its surface. (2) Stir the reaction solution for 8-10 hours, then centrifuge the reaction solution and wash the precipitate with water until the wastewater is neutral to obtain carboxyl-modified quartz powder.

2. The novel polishing pad according to claim 1, characterized in that, The waterborne resin is a waterborne polyurethane-acrylic acid copolymer resin.

3. The novel polishing pad according to claim 1, characterized in that, The amino-modified quartz powder is prepared according to the following method: (1) Mix γ-aminopropyltriethoxysilane, water and ethanol to obtain a silane-modified solution; add quartz powder to an aqueous dispersant and stir to obtain a quartz impregnation solution; the amount of γ-aminopropyltriethoxysilane is 6-8% of the weight of the quartz powder; (2) Mix the silane-modified liquid and the quartz impregnation liquid, stir and heat them, and then filter them. Wash and dry the solid obtained by filtration to obtain amino-modified quartz powder.

4. The novel polishing pad according to claim 3, characterized in that, The molar ratio of benzotriglyceride to γ-aminopropyltriethoxysilane is (1.25-1.35):

1.

5. The novel polishing pad according to claim 4, characterized in that, The aqueous dispersant is silica sol.

6. The novel polishing pad according to claim 5, characterized in that, In step (1) of preparing the amino-modified quartz powder, halloysite nanotubes and quartz powder are added together to an aqueous dispersant.

7. The novel polishing pad according to claim 6, characterized in that, The amount of halloysite nanotubes used is 5-8% of the weight of the quartz powder.

8. The method for manufacturing the novel polishing pad according to any one of claims 1-7, characterized in that, Includes the following steps: (1) The polymer fibers are woven into a web and then needle-punched to obtain a nonwoven fabric layer; (2) Mix water-based resin, modified quartz powder and polycarbodiimide to obtain impregnation slurry, coat the impregnation slurry on the surface of nonwoven fabric layer, and then dry it to cure the impregnation slurry on the surface of nonwoven fabric layer. (3) The cured product containing the impregnated slurry is polished to obtain a new type of polishing pad.

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