Defoaming agent for cooling liquid of diamond wire cutting silicon wafer and preparation method of defoaming agent

Abstract

The invention discloses a defoaming agent for cooling liquid of a diamond wire cut silicon wafer and a preparation method of the defoaming agent, and the preparation method of the defoaming agent comprises the following steps: S1, sequentially adding hydrogen-containing silicone oil and allyl polyether according to a molar ratio of 1: 1-1: 3, uniformly stirring, adding chloroplatinic acid as a catalyst, and synthesizing organic silicon block polyether; s2, uniformly stirring the organic silicon block polyether obtained in the step S1 and dimethyl silicone oil to obtain a mixed solution; s3, uniformly mixing the mixed solution obtained in the step S2 with sorbitan monostearate, dropwise adding a hydroxypropyl methyl cellulose solution into the mixed solution, slowly and uniformly stirring, adding deionized water, and uniformly stirring to obtain the organic silicon modified polyether defoaming agent. The defoaming agent disclosed by the invention is a micromolecular defoaming agent, has the characteristics of strong universality, strong defoaming power, low volatility, no toxicity and stability, and has universality.

Description

Technical field:

[0001] The invention belongs to the technical field of defoamers, and particularly relates to a defoamer for cooling liquid of diamond wire cutting silicon wafers and a preparation method thereof. Background technology:

[0002] Slicing is an important part of silicon wafer processing, which has a significant impact on raw material utilization and cost control. Diamond wire cutting is a process that uses a thin steel wire with a diamond coating as a cutting tool to cut single crystal silicon into thin slices through a high-speed rotating wire saw. It can not only increase the cutting speed, but also reduce the waste of silicon materials. Therefore, it is widely used in the field of silicon wafer processing. Cutting fluid is the processing medium in the diamond wire cutting process. It mainly plays the role of lubrication and cooling. During the production process, a large amount of foam often appears in the cutting fluid, which has a certain impact on production efficiency and finished product quality. Therefore, defoaming agents are of great significance to cutting fluids.

[0003] In order to eliminate the foam during the cutting process, most of the existing diamond wire cutting fluids use macromolecules such as emulsified silicone oil, ethers and polydimethylsilane as defoamers. However, due to the large molecular weight of the defoamer, it is easier to be broken up or its structure is destroyed during the process of rapid cutting and dispersion, which affects the cutting performance and quality, and the tiny foam generated by the diamond wire cutting fluid in the prior art during the cutting process is difficult to eliminate, thereby causing problems such as poor thermal conductivity. In addition, there are also some small molecule defoamers, such as the authorized patent "CN201910257258.2 A small molecular weight acetylene glycol nonionic surfactant" recorded, but the acetylene glycol defoamer has a good defoaming effect at low viscosity and low elasticity, but the defoaming effect is insufficient in a high viscosity system, so the development of a defoamer with strong defoaming ability and strong universality is of great significance for actual production.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention:

[0005] The object of the present invention is to provide a defoaming agent for cooling liquid of diamond wire cutting silicon wafers and a preparation method thereof, so as to overcome the defects in the above-mentioned prior art.

[0006] In order to achieve the above object, the present invention provides a defoaming agent for a coolant of a diamond wire cut silicon wafer, and the molecular formula of the defoaming agent is as follows:

[0007]

[0008] In the formula, n=1m=1-5.

[0009] The present invention also provides a method for preparing the above-mentioned defoaming agent for the cooling liquid of the diamond wire cutting silicon wafer, comprising the following steps:

[0010] S1: adding hydrogen-containing silicone oil and allyl polyether in sequence, with the molar ratio of the two being 1:1-1:3, stirring evenly, and then adding chloroplatinic acid as a catalyst to synthesize silicone block polyether;

[0011] S2: stirring the organosilicon block polyether and dimethyl silicone oil obtained in step S1 to obtain a mixed solution;

[0012] S3: The mixed solution obtained in step S2 and sorbitan monostearate are mixed evenly, and then the hydroxypropyl methylcellulose solution is added dropwise to the mixed solution, and after slowly stirring evenly, deionized water is added and stirred evenly to obtain an organosilicon-modified polyether defoamer.

[0013] Further, as a preference, the reaction in S1 is as shown below:

[0014]

[0015] In the formula, n=1m=1-5.

[0016] Further, preferably, the amount of chloroplatinic acid added in S1 is 0.1-1.0%, and the synthesis temperature is 110-140°C.

[0017] Further, preferably, the molecular weight of the hydrogen-containing silicone oil in S1 is 208.

[0018] Furthermore, preferably, the molecular weight of the allyl polyether in S1 is 102, 146, 190, 234, 278, and the EO number of the polyether is 1, 2, 3, 4, 5, respectively.

[0019] Furthermore, preferably, the mass ratio of the organosilicon block polyether to the dimethyl silicone oil in S2 is 1:1-5:1, the stirring temperature is 110-140° C., and the stirring time is 3-5 h.

[0020] Furthermore, preferably, the mass ratio of the mixed solution in S3 to sorbitan monostearate is 1:1-5:1, the mixing temperature of the two is 40-80°C, and the mixing time is 0.5-2h.

[0021] Furthermore, preferably, the concentration of the hydroxypropyl methylcellulose solution in S3 is 1.5-2%, and the stirring time is 0.5-2h.

[0022] Furthermore, preferably, deionized water is added to S3 and stirred to room temperature, and then subjected to high-speed shearing at 4500-5500 r / min for 3-10 min to obtain the organosilicon-modified polyether defoamer.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention is a small molecule defoamer with the characteristics of strong universality, strong defoaming power, low volatility, non-toxicity, stability, and universality. Specific implementation method:

[0025] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0026] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0027] Embodiment 1:

[0028] A method for preparing a defoaming agent for a coolant for diamond wire cutting of silicon wafers comprises the following steps:

[0029] S1: In a three-necked flask, hydrogenated silicone oil with a molecular weight of 208 and allyl polyether with a molecular weight of 102 were added in sequence, with the molar ratio of the two being 1:1.2, stirred evenly, and then heated to 130° C., 0.3% chloroplatinic acid was added as a catalyst, and an organosilicon block polyether with a molecular weight of 310.61 was synthesized under catalytic conditions;

[0030] The reaction formula is as follows:

[0031]

[0032] Where n = 1m = 1;

[0033] S2: adding the organosilicon block polyether obtained in step S1 and dimethyl silicone oil into a flask in a mass ratio of 4:1, stirring at 130° C. for 4 h to obtain a mixed solution;

[0034] S3: Weigh 20 g of the mixed solution obtained in step S2, and then weigh 5 g of sorbitan monostearate (Span-60), add the two into a flask in turn, and stir at a constant temperature of 60°C for 1 hour. Then, add 24 g of 2% hydroxypropyl methylcellulose solution dropwise into the solution, stir slowly for 1 hour, and then add 35 g of deionized water, stir to room temperature, and prepare a new silicone modified polyether defoamer after high-speed shearing at 5000 r / min for 5 minutes.

[0035] Embodiment 2:

[0036] A method for preparing a defoaming agent for a coolant for diamond wire cutting of silicon wafers comprises the following steps:

[0037] S1: In a three-necked flask, hydrogenated silicone oil with a molecular weight of 208 and allyl polyether with a molecular weight of 146 were added in sequence, the molar ratio of the two being 1:1.2, stirred evenly, and then heated to 130° C., 0.3% chloroplatinic acid was added as a catalyst, and an organosilicon block polyether with a molecular weight of 354.66 was synthesized under catalytic conditions; the reaction formula was the same as that in Example 1, except that n=1 and m=2;

[0038] S2: adding the organosilicon block polyether obtained in step S1 and dimethyl silicone oil into a flask in a mass ratio of 4:1, stirring at 130° C. for 4 h to obtain a mixed solution;

[0039] S3: Weigh 20 g of the mixed solution obtained in step S2, and then weigh 5 g of sorbitan monostearate (Span-60), add the two into a flask in turn, and stir at a constant temperature of 60°C for 1 hour. Then, add 24 g of 2% hydroxypropyl methylcellulose solution dropwise into the solution, stir slowly for 1 hour, and then add 35 g of deionized water, stir to room temperature, and prepare a new silicone modified polyether defoamer after high-speed shearing at 5000 r / min for 5 minutes.

[0040] Embodiment 3:

[0041] A method for preparing a defoaming agent for a coolant for diamond wire cutting of silicon wafers comprises the following steps:

[0042] S1: In a three-necked flask, hydrogenated silicone oil with a molecular weight of 208 and allyl polyether with a molecular weight of 190 were added in sequence, and the molar ratio of the two was 1:1.2. After stirring evenly, the temperature was raised to 130° C., and 0.3% chloroplatinic acid was added as a catalyst to synthesize an organosilicon block polyether with a molecular weight of 398.71 under catalytic conditions; the reaction formula was the same as that in Example 1, except that n=1 and m=3;

[0043] S2: adding the organosilicon block polyether obtained in step S1 and dimethyl silicone oil into a flask in a mass ratio of 4:1, stirring at 130° C. for 4 h to obtain a mixed solution;

[0044] S3: Weigh 20 g of the mixed solution obtained in step S2, and then weigh 5 g of sorbitan monostearate (Span-60), add the two into a flask in turn, and stir at a constant temperature of 60°C for 1 hour. Then, add 24 g of 2% hydroxypropyl methylcellulose solution dropwise into the solution, stir slowly for 1 hour, and then add 35 g of deionized water, stir to room temperature, and prepare a new silicone modified polyether defoamer after high-speed shearing at 5000 r / min for 5 minutes.

[0045] Embodiment 4:

[0046] A method for preparing a defoaming agent for a coolant for diamond wire cutting of silicon wafers comprises the following steps:

[0047] S1: In a three-necked flask, hydrogenated silicone oil with a molecular weight of 208 and allyl polyether with a molecular weight of 234 were added in sequence, the molar ratio of the two being 1:1.2, stirred evenly, and then heated to 130° C., 0.3% chloroplatinic acid was added as a catalyst, and an organosilicon block polyether with a molecular weight of 442.77 was synthesized under catalytic conditions; the reaction formula was the same as that in Example 1, except that n=1 and m=4;

[0048] S2: adding the organosilicon block polyether obtained in step S1 and dimethyl silicone oil into a flask in a mass ratio of 4:1, stirring at 130° C. for 4 h to obtain a mixed solution;

[0049] S3: Weigh 20 g of the mixed solution obtained in step S2, and then weigh 5 g of sorbitan monostearate (Span-60), add the two into a flask in turn, and stir at a constant temperature of 60°C for 1 hour. Then, add 24 g of 2% hydroxypropyl methylcellulose solution dropwise into the solution, stir slowly for 1 hour, and then add 35 g of deionized water, stir to room temperature, and prepare a new silicone modified polyether defoamer after high-speed shearing at 5000 r / min for 5 minutes.

[0050] Embodiment 5:

[0051] A method for preparing a defoaming agent for a coolant for diamond wire cutting of silicon wafers comprises the following steps:

[0052] S1: In a three-necked flask, hydrogenated silicone oil with a molecular weight of 208 and allyl polyether with a molecular weight of 278 were added in sequence, the molar ratio of the two being 1:1.2, stirred evenly, and then heated to 130° C., 0.3% chloroplatinic acid was added as a catalyst, and an organosilicon block polyether with a molecular weight of 486.82 was synthesized under catalytic conditions; the reaction formula was the same as that in Example 1, except that n=1 and m=5;

[0053] S2: adding the organosilicon block polyether obtained in step S1 and dimethyl silicone oil into a flask in a mass ratio of 4:1, stirring at 130° C. for 4 h to obtain a mixed solution;

[0054] S3: Weigh 20 g of the mixed solution obtained in step S2, and then weigh 5 g of sorbitan monostearate (Span-60), add the two into a flask in turn, and stir at a constant temperature of 60°C for 1 hour. Then, add 24 g of 2% hydroxypropyl methylcellulose solution dropwise into the solution, stir slowly for 1 hour, and then add 35 g of deionized water, stir to room temperature, and prepare a new silicone modified polyether defoamer after high-speed shearing at 5000 r / min for 5 minutes.

[0055] The cooling liquid was prepared according to the following weight percentages: 2% of the defoamer prepared in Examples 1-5, 22% of the dispersant, 1% of the stabilizer, and 75% of the solvent. The prepared cooling liquids were diluted by 0.5% respectively to obtain five groups of cooling liquids. Specifically, the dispersant was an anionic dispersant, the stabilizer was a silicate, and the solvent was pure water.

[0056] Comparative Example 1:

[0057] Compared with the above-mentioned embodiments 1-5, the defoaming agent adopts commercially available high molecular weight emulsified silicone oil (molecular weight greater than 500).

[0058] Comparative Example 2:

[0059] Compared with the above-mentioned embodiments 1-5, no defoaming agent is added to the cooling liquid.

[0060] The coolants of the above-mentioned Examples 1-5 and Comparative Example 1 and Comparative Example 2 were tested, and the testing method was as follows:

[0061] A 24 μm tungsten diamond wire was used to cut a 182*182 silicon wafer. The cutting process was normal without wire breakage, overcutting, or silicon wafer contamination. The cutting experiments were divided into seven groups, using the coolants of Examples 1-5 and Comparative Examples 1 and 2, respectively.

[0062] After the cutting is completed, take 50mL of coolant respectively, use the foam analyzer to stir at 40r / min for 30s, test the foam height, defoaming time and dirty wafer rate (the dirty wafer rate is calculated by cutting 500 silicon wafers). The test results are shown in the following table:

[0063] project Foam height mm Defoaming time / s Dirt rate Example 1 17 4 0.40％ Example 2 16 4 0.40％ Example 3 15 4 0.43％ Example 4 15 4 0.50％ Example 5 14 3 0.56％ Comparative Example 1 13 10 0.65％ Comparative Example 2 30 60 1.20％

[0064] From the test results, compared with the blank without added defoamer (Comparative Example 2) and the coolant of Comparative Example 1, Examples 1-5 have lower foam height and shorter defoaming time, and the use of higher molecular weight allyl polyether has the best effect, but the molecular weight generated is lower than the molecular weight of the currently reported emulsified silicone oil. In addition, the defoamer also has good defoaming performance in the high viscosity of ink.

[0065] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A defoaming agent for cooling liquid of diamond wire cutting silicon wafers, characterized in that: The molecular formula of the defoamer is as follows: In the formula, n=1m=1-5.

2. A method for preparing the defoaming agent for cooling liquid of diamond wire cutting silicon wafers according to claim 1, characterized in that: The following steps are involved: S1: adding hydrogen-containing silicone oil and allyl polyether in sequence, with the molar ratio of the two being 1:1-1:3, stirring evenly, and then adding chloroplatinic acid as a catalyst to synthesize silicone block polyether; S2: stirring the organosilicon block polyether and dimethyl silicone oil obtained in step S1 to obtain a mixed solution; S3: The mixed solution obtained in step S2 and sorbitan monostearate are mixed evenly, and then the hydroxypropyl methylcellulose solution is added dropwise to the mixed solution, and after slowly stirring evenly, deionized water is added and stirred evenly to obtain an organosilicon-modified polyether defoamer.

3. The method for preparing the defoaming agent for cooling liquid of diamond wire cutting silicon wafers according to claim 1 according to claim 2, characterized in that: The reaction in S1 is shown below: In the formula, n=1m=1-5.

4. The method for preparing the defoaming agent for the coolant of the diamond wire cutting silicon wafer according to claim 1 according to claim 2, characterized in that: The amount of chloroplatinic acid added in S1 is 0.1-1.0%, and the synthesis temperature is 110-140°C.

5. The method for preparing the defoaming agent for the coolant of the diamond wire cutting silicon wafer according to claim 1 according to claim 2, characterized in that: The molecular weight of the hydrogen-containing silicone oil in S1 is 208.

6. The method for preparing the defoaming agent for cooling liquid of diamond wire cutting silicon wafers according to claim 1 according to claim 2, characterized in that: The mass ratio of the organosilicon block polyether to the dimethyl silicone oil in the S2 is 1:1-5:1, and the stirring temperature is 110-140°C.

7. The method for preparing the defoaming agent for cooling liquid of diamond wire cutting silicon wafers according to claim 1 according to claim 2, characterized in that: The mass ratio of the mixed solution in S3 to sorbitan monostearate is 1:1-5:1, and the mixing temperature of the two is 40-80°C.

8. The method for preparing the defoaming agent for cooling liquid of diamond wire cutting silicon wafers according to claim 1 according to claim 2, characterized in that: The concentration of the hydroxypropyl methylcellulose solution in S3 is 1.5-2%.

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