A polishing material for silicon carbide fine polishing and a method for preparing the same

Abstract

The application relates to a polishing material, and particularly discloses a polishing material for fine polishing of silicon carbide and a preparation method of the polishing material. The polishing material for fine polishing of silicon carbide is prepared from raw materials including a carrier, a polyurethane coating and a polyethylene terephthalate film. The raw materials of the polyurethane coating include the following components in parts by weight: 80-120 parts of polyurethane resin, 40-60 parts of solvent and 1-20 parts of surfactant. The raw materials of the polyurethane resin include the following components in parts by weight: 20-35 parts of polyol composition, 0.1-1 part of chain extender, 3-9 parts of isocyanate, 60-70 parts of solvent and 0.02-0.04 part of end-capping agent. The polishing material has good oxidation resistance and a long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to a polishing material, in particular to a polishing material for fine polishing of silicon carbide and a preparation method thereof. BACKGROUND

[0002] Silicon carbide is a semiconductor material composed of carbon and silicon elements, which has the characteristics of high temperature resistance, high frequency resistance and high pressure resistance. In integrated circuit and electronic device manufacturing, the multi-layer conductive material, semiconductor material and dielectric material deposited on the surface of semiconductor wafer or wafer need to be removed, and chemical mechanical planar polishing is the most commonly used technology for workpiece surface polishing at present. When polishing with a polishing material, polishing liquid needs to be used for polishing, and the polishing liquid contains some peroxides, which can oxidize the polishing material, thereby shortening the service life of the polishing material. SUMMARY

[0003] In order to improve the oxidation resistance of the polishing material, the present application provides a polishing material for fine polishing of silicon carbide and a preparation method thereof.

[0004] In the first aspect, the present application provides a polishing material for fine polishing of silicon carbide, which adopts the following technical scheme: a polishing material for fine polishing of silicon carbide, the raw materials of the polishing material include a carrier, a polyurethane coating and a polyethylene terephthalate film; the raw materials of the polyurethane coating include the following components in parts by weight: polyurethane resin 80-120 parts, solvent 40-60 parts, and surfactant 1-20 parts; the raw materials of the polyurethane resin include the following components in parts by weight: polyol composition 20-35 parts, chain extender 0.1-1 part, isocyanate 3-9 parts, solvent 60-70 parts, and blocking agent 0.02-0.04 parts.

[0005] By adopting the above technical scheme, the polyurethane material with microporous structure formed by the carrier and the polyurethane coating can polish the surface of the workpiece; the polyurethane resin synthesized by the polyol composition and the isocyanate has strong oxidation resistance, so that the polishing material is not easily oxidized by the polishing liquid during polishing, thereby improving the service life of the polishing material.

[0006] In a specific implementable embodiment, the polyol composition includes a mixture of polytetrahydrofuran diol and polyester diol.

[0007] In a specific implementable embodiment, the polyester diol is a linear high molecular polymer formed by high-temperature dehydration polycondensation of a dibasic acid and a dihydric alcohol, and both ends of the molecular chain are hydroxyl groups that can react with isocyanate; the dibasic acid includes one or more of adipic acid, succinic acid and aliphatic or aromatic dibasic carboxylic acid with a molecular weight less than 300; the dihydric alcohol contains one or more side chains, and the carbon chain length of the one or more side chains is greater than 2.

[0008] In one specific implementation, the polyol composition further includes one or more of polycarbonate diols, polycaprolactone diols, lactone copolymers, polyester diols.

[0009] In one specific implementation, the mass fraction of the polytetrahydrofuran diol and the polyester diol in the polyol composition is 30%-100%.

[0010] By using the above technical solution, the polyol composition is composed of polyester diols and polytetrahydrofuran diols which are formed by high-temperature dehydration and polycondensation of diacids and diols, and the use amount of the polyester diols and the polytetrahydrofuran diols is further limited, so that the prepared polishing material has higher oxidation resistance.

[0011] In one specific implementation, the chain extender includes one or more of ethylene glycol, 1,4-butanediol, and ethylenediamine.

[0012] In one specific implementation, the raw material of the polyurethane resin further includes 0.01-0.1 parts by weight of an auxiliary agent, and the auxiliary agent includes an antioxidant, an ultraviolet light absorber, a cell regulator, and modified silicone oil.

[0013] By using the above technical solution, the addition of the antioxidant and the ultraviolet light absorber can further improve the oxidation resistance of the prepared polishing material.

[0014] In a second aspect, the application provides a preparation method of a polishing material for silicon carbide fine polishing, which adopts the following technical solution:

[0015] A preparation method of a polishing material for silicon carbide fine polishing, including the following steps:

[0016] Synthesis of polyester diols: the diacids and diols are put into a reaction kettle, stirred at 90-100°C under the protection of nitrogen, then reacted at 150-160°C for 1.5-2.5h, and then heated to 220-230°C, vacuum is opened until the hydroxyl value of the material is 54-58mgKOH / g and the acid value is 0.1-0.5mgKOH / g, the vacuum is stopped, and the temperature is lowered to 120°C to discharge the material, to obtain polyester diols;

[0017] Synthesis of polyurethane resin: part of solvent and part of polyol composition are added into a reaction kettle and stirred uniformly, part of isocyanate is added at 25-35℃, the temperature is raised to 65-75℃, part of solvent, the rest of polyol composition and chain extender are added, the temperature is lowered to 45-55℃, the rest of isocyanate is added after stirring uniformly, the reaction is carried out at 75-85℃ until the viscosity of the reactants is 150000cps / 25℃, then the rest of solvent and blocking agent are added, the reaction is carried out at 70-80℃ for 0.5-1.5h, finally the auxiliary is added and the reaction is carried out for 0.5-1.5h, the product is discharged after cooling, and polyurethane resin is obtained;

[0018] Compounding: the polyurethane resin, solvent, surfactant and colorant are stirred and mixed uniformly, filtered and vacuum degassed, coated on a carrier, then put into water to solidify, washed, dried, sliced, polished, and a polyurethane coating layer is formed on the carrier to obtain a polyurethane material; hot melt adhesive is coated on a polyethylene terephthalate film, and then compounded on the polyurethane material to obtain a polishing material.

[0019] By using the above technical scheme, the peroxide-resistant polyester diol is first synthesized, then part of the polyol composition containing the polyester diol and part of the isocyanate are dissolved in part of the solvent to carry out a certain degree of pre-polymerization, so that the system has a certain viscosity, and then the rest of the polyol composition and isocyanate and small molecule chain extender are added for secondary polymerization, thereby improving the oxidation resistance of the polishing material.

[0020] In summary, the present application has at least one of the following beneficial technical effects:

[0021] 1. The polyurethane material with a microporous structure formed by the carrier and the polyurethane coating layer in the present application can polish the surface of a workpiece; the polyurethane resin synthesized by the polyol composition and the isocyanate has strong oxidation resistance, so that the polishing material is not easily oxidized by the polishing liquid during polishing, thereby improving the service life of the polishing material;

[0022] 2. The polyurethane resin synthesized by the polyol composition and the isocyanate in the present application has strong oxidation resistance, so that the polyurethane coating layer formed is not easily oxidized by the polishing liquid, and the polyurethane material with a microporous structure formed by the carrier and the polyurethane coating layer can polish the surface of a workpiece, thereby improving the polishing effect of the polishing material;

[0023] 3. The method in the present application, first synthesizes the peroxide-resistant polyester diol, then in the synthesis of the polyurethane resin, first dissolves part of the polyol composition containing the polyester diol and part of the isocyanate in part of the solvent, prepolymers to a certain extent, so that the system has a certain viscosity, then the rest of the polyol composition and isocyanate and small molecule chain extender are added to carry out secondary polymerization, thereby improving the oxidation resistance of the prepared polishing material. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 、 2 is a structural schematic diagram of the polishing material in the embodiment of the present application. DETAILED DESCRIPTION

[0025] The present application is further described in detail below in combination with the embodiments.

[0026] All raw materials in the embodiments can be obtained by market purchase. Among them, the isocyanate is 4,4-diphenyl methane diisocyanate; the antioxidant is type 1010; the ultraviolet light absorber is type UV531; the cell regulator CAS number is 63148-62-9; the modified silicone oil CAS number is 68937-55-3; the carrier is PE / PVC material or glass plate.

[0027] EMBODIMENT

[0028] EMBODIMENT 1

[0029] Embodiment 1 provides a preparation method of a polishing material for silicon carbide fine polishing, comprising the following steps:

[0030] Synthesis of polyester diol: 200 parts of diacid and 212.6 parts of diol are put into a reaction kettle, under the protection of nitrogen, first stirred at 95℃, then constant temperature reaction at 155℃ for 2h, then heated to 225℃, when the water output is 1 / 8 of the weight of the diacid, open the vacuum, until the hydroxyl value of the material is 54-58mgKOH / g and the acid value is 0.1-0.5mgKOH / g, stop vacuum, cool to 120℃ to discharge, obtain polyester diol, and the hydroxyl value of the polyester diol is 56.3mgKOH / g, the acid value is 0.3mgKOH / g; wherein the diacid is adipic acid; the diol is a mixture of 1,6-hexanediol and 2-methyl-1,3 propanediol, and the weight ratio of adipic acid, 1,6-hexanediol and 2-methyl-1,3 propanediol is 200:123:89.6;

[0031] Synthesis of the polyurethane resin: part of the solvent and part of the polyol composition were added into a reaction kettle and stirred uniformly, part of the isocyanate was added at 30℃, the temperature was raised to 70℃, when the reaction viscosity was 80000 cps / 70℃, part of the solvent, the remaining polyol composition, 0.1 kg of chain extender were added, the temperature was lowered to 50℃, after stirring uniformly, the remaining isocyanate was added, the reaction was carried out at 80℃ until the viscosity of the reaction was 150000 cps / 25℃, then the remaining solvent, 0.02 kg of blocking agent were added, and the reaction was carried out at 75℃ for 1 h, and the product was discharged after cooling; wherein the solvent was N,N-dimethylformamide, the weight was 60 kg, and the weight ratio of the three times of adding the solvent was 2:2:1; the polyol composition was a mixture of polytetrahydrofuran diol and polyester diol, and the weight ratio of polytetrahydrofuran diol and polyester diol was 1:1; the weight of the polyol composition was 20 kg, and the weight ratio of the two times of adding the polyol composition was 7:3; the weight of the isocyanate was 3 kg, and the weight ratio of the two times of adding the isocyanate was 1:4; the chain extender was ethylene glycol; and the blocking agent was methanol;

[0032] Compounding: 80 kg of the polyurethane resin, 40 kg of the solvent, 1 kg of the surfactant, and 3 kg of the colorant were stirred and mixed uniformly, filtered, vacuum degassed, coated on a carrier, and then placed in water to solidify, washed, dried, sliced, polished, to form a polyurethane coating layer on the carrier, thereby obtaining a polyurethane material; hot melt adhesive was coated on a polyethylene terephthalate film, and then compounded on the polyurethane material to obtain a polishing material, and a structure diagram of the polishing material is shown in Figure 1 、 2 ; wherein the solvent was N,N-dimethylformamide; the surfactant was a polysiloxane-polyoxyalkylene ether block copolymer; the colorant was selected according to the required color; and the carrier was a PE material.

[0033] Example 2

[0034] The difference between Example 2 and Example 1 is that in the synthesis step of the polyurethane resin, part of the solvent and part of the polyol composition are added into the reaction kettle and stirred uniformly, part of the isocyanate is added at 30°C, the temperature is raised to 70°C, when the reaction viscosity is 80000 cps / 70°C, part of the solvent, the remaining polyol composition, 0.1 kg of chain extender are added, the temperature is lowered to 50°C, after stirring uniformly, the remaining isocyanate is added, and the reaction is carried out at 80°C until the viscosity of the reactants is 150000 cps / 25°C, then the remaining solvent, 0.02 kg of end-capping agent, is added, and stirred at 75°C for 1 h, then 0.05 of the auxiliary is added, and stirred for 1 h, and then cooled and discharged to obtain the polyurethane resin; wherein the weight ratio of the antioxidant, the ultraviolet light absorber, the cell regulator, and the modified silicone oil is 1:1:1:1; the remaining steps are consistent with Example 1.

[0035] Example 3

[0036] The difference between Example 3 and Example 2 is that in the synthesis step of the polyurethane resin, the weight of the polyol composition is 27 kg, the weight of the chain extender is 0.5 kg, the weight of the isocyanate is 6 kg, the weight of the solvent is 65 kg, and the weight of the end-capping agent is 0.03 kg; in the compounding step: 100 kg of polyurethane resin, 50 kg of solvent, 10 kg of surfactant, and 6 kg of colorant are stirred and mixed uniformly, then filtered and vacuum degassed to coat on the carrier, then placed in water to solidify, washed, dried, sliced, polished, to form a polyurethane coating on the carrier, and obtain a polyurethane material; the remaining steps are consistent with Example 2.

[0037] Example 4

[0038] The difference between Example 4 and Example 2 is that in the synthesis step of the polyurethane resin, the weight of the polyol composition is 35 kg, the weight of the chain extender is 1 kg, the weight of the isocyanate is 9 kg, the weight of the solvent is 70 kg, and the weight of the end-capping agent is 0.04 kg; in the compounding step: 120 kg of polyurethane resin, 60 kg of solvent, 20 kg of surfactant, and 10 kg of colorant are stirred and mixed uniformly, then filtered and vacuum degassed to coat on the carrier, then placed in water to solidify, washed, dried, sliced, polished, to form a polyurethane coating on the carrier, and obtain a polyurethane material; the remaining steps are consistent with Example 2.

[0039] Example 5

[0040] The difference between Example 5 and Example 3 is that the polyol composition is a mixture of polytetrahydrofuran diol and polycarbonate diol, and the weight ratio of polytetrahydrofuran diol to polycarbonate diol is 1:1; the remaining steps are consistent with Example 3.

[0041] Example 6

[0042] Example 6 differs from Example 3 in that the polyol composition is a mixture of polycaprolactone diol and polyester diol, and the weight ratio of polycaprolactone diol to polyester diol is 1:1; the remaining steps are consistent with Example 3.

[0043] Comparative Example

[0044] Comparative Example 1

[0045] Comparative Example 1 provides a method for preparing a polishing material, comprising the following steps:

[0046] After 80 kg of polyurethane resin, 40 kg of solvent, 1 kg of surfactant, and 3 kg of colorant are stirred and mixed uniformly, they are filtered and vacuum degassed to be coated on a carrier, and then placed in water to solidify, washed, dried, sliced, polished, to form a polyurethane coating on the carrier, thereby obtaining a polyurethane material; hot melt adhesive is coated on a polyethylene terephthalate film, and then compounded on the polyurethane material, thereby obtaining a polishing material; wherein the polyurethane resin has a CAS number of 9009-54-5; the solvent is N,N-dimethylformamide; the surfactant is a polysiloxane-polyoxyalkylene ether block copolymer; the colorant is selected according to the required color; and the carrier is a PE material.

[0047] Performance detection test

[0048] Oxidation resistance: the polishing materials in each example and comparative example are placed in 30% hydrogen peroxide at 24°C, and the time at which the polyurethane coating on the polishing material can be scraped off is detected; the longer the time, the better the oxidation resistance of the polishing material.

[0049] Table 1: Performance detection results of the polishing materials

[0050] Sample Oxidation resistance time (h) Example 1 192 Example 2 220 Example 3 228 Example 4 225 Example 5 180 Example 6 185 Comparative Example 1 100

[0051] In combination with Example 1 and Comparative Example 1, the oxidation resistance of the polishing material in Example 1 is better, which shows that the polyurethane resin synthesized using the polyol composition and isocyanate has strong oxidation resistance, thereby improving the service life of the polishing material.

[0052] In combination with Example 1 and Example 2, the oxidation resistance of the polishing material in Example 2 is better, which shows that adding antioxidants and ultraviolet light absorbers to the raw materials during the synthesis of the polyurethane resin can further improve the oxidation resistance of the prepared polishing material.

[0053] In combination with Examples 2-4, the oxidation resistance of the polishing materials in Examples 2-4 is not much different, which shows that increasing the usage amount of the raw materials during the synthesis of the polyurethane resin and the compounding of the polishing material has little effect on the oxidation resistance of the prepared polishing material.

[0054] In combination with Example 3, Example 5 and Example 6, the polishing material of Example 3 has the best antioxidation performance, which shows that when the polyurethane resin is synthesized, the polyol composition is selected as a mixture of polytetrahydrofuran diol and polyester diol, the antioxidation performance of the polyurethane resin prepared is better, and thus the service life of the polishing material is longer.

[0055] 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, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A polishing material for polishing of silicon carbide, characterized by: The raw material of the polishing material comprises a carrier, a polyurethane coating, and a polyethylene terephthalate film; the raw material of the polyurethane coating comprises the following components in parts by weight: 80-120 parts of a polyurethane resin, 40-60 parts of a solvent, and 1-20 parts of a surfactant; the raw material of the polyurethane resin comprises the following components in parts by weight: 20-35 parts of a polyol composition, 0.1-1 part of a chain extender, 3-9 parts of an isocyanate, 60-70 parts of a solvent, 0.02-0.04 parts of an end-capping agent, and 0.01-0.1 parts of an auxiliary agent; the polyol composition comprises a mixture of polytetrahydrofuran diol and polyester diol; the polyester diol is a linear polymer formed by high-temperature dehydration and polycondensation of a diacid and a diol, and both ends of the molecular chain are hydroxyl groups that can react with isocyanate; the diacid comprises one or more of adipic acid, succinic acid, and aliphatic or aromatic dicarboxylic acids with a molecular weight of less than 300; the diol contains one or more side chains, and the carbon chain length of the one or more side chains is greater than 2; and the preparation method of the polishing material comprises the following steps: Synthesis of the polyester diol: the diacid and the diol are put into a reaction kettle, stirred at 90-100 DEG C under the protection of nitrogen, then reacted at 150-160 DEG C for 1.5-2.5 h, and then heated to 220-230 DEG C, vacuum is opened until the hydroxyl value of the material is 54-58 mgKOH / g and the acid value is 0.1-0.5 mgKOH / g, the vacuum is stopped, and the temperature is lowered to 120 DEG C to discharge the material, thereby obtaining the polyester diol; Synthesis of the polyurethane resin: part of the solvent and part of the polyol composition are added into a reaction kettle and stirred uniformly, part of the isocyanate is added at 25-35 DEG C, the temperature is raised to 65-75 DEG C, part of the solvent, the remaining polyol composition, and the chain extender are added, the temperature is lowered to 45-55 DEG C, the remaining isocyanate is added after uniform stirring, the reaction is carried out at 75-85 DEG C until the viscosity of the reactants is 150000 cps / 25 DEG C, then the remaining solvent and the end-capping agent are added, the reaction is carried out at 70-80 DEG C for 0.5-1.5 h, the auxiliary agent is finally added for further stirring reaction for 0.5-1.5 h, and the product is discharged after cooling, thereby obtaining the polyurethane resin; the auxiliary agent comprises an antioxidant, an ultraviolet light absorber, a cell regulator, and modified silicone oil; Compounding: the polyurethane resin, the solvent, the surfactant, and the colorant are stirred and mixed uniformly, filtered, vacuum degassed, coated on the carrier, then placed in water for solidification, washed, dried, sliced, polished, and compounded on the polyethylene terephthalate film, thereby obtaining the polishing material.

2. A polishing material for polishing silicon carbide according to claim 1, wherein: The polyol composition further comprises one or more of polycarbonate diol, polycaprolactone diol, and polyester diol.

3. A polishing material for polishing silicon carbide according to claim 2, wherein: The mass fraction of the polytetrahydrofuran diol and the polyester diol in the polyol composition is 30%-100%.

4. The polishing material for polishing of silicon carbide according to claim 1, wherein: The chain extender comprises one or more of ethylene glycol, 1,4 butanediol, and ethylenediamine.

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