A cutting fluid for free abrasive multi-wire cutting, preparation method and application thereof

Abstract

The invention discloses a cutting fluid for free abrasive multi-wire cutting, a preparation method and an application thereof. The cutting fluid for free abrasive multi-wire cutting comprises the following components by weight percentage: 35-55% of trimethylolpropane oleate, 15-35% of isooctyl stearate, 10-25% of isooctyl ester, 0.5-1% of sodium petroleum sulfonate, 0.2-1% of butylated hydroxytoluene, 5-15% of 25% sodium metasilicate solution and 0.2-1% of fatty alcohol polyoxyethylene ether. The cutting fluid for free abrasive multi-wire cutting of the invention is applied to multi-wire cutting of germanium single crystals, and the obtained germanium slices can be soaked and rinsed in clean water to obtain clean germanium slices, thereby eliminating the cumbersome steps of kerosene soaking and special cleaning agent cleaning in the original process, reducing the process flow, improving production efficiency and reducing costs; the preparation is simple, easy to operate and easy to promote industrialization.

Description

Technical Field

[0001] The invention relates to a cutting fluid for free abrasive multi-wire cutting, a preparation method and application thereof, and belongs to the technical field of semiconductor material processing. Background Art

[0002] Multi-wire cutting is one of the important processes for processing photovoltaic germanium single crystals into substrates for space power supply. The current mainstream process uses free abrasive wire cutting technology, and a few use corundum wire cutting technology. The advantages of the free abrasive wire cutting process are that the surface roughness of the germanium slices produced is low, the finish is high, the thickness consistency is high, and the flexural strength of the slices is high. The disadvantages are also significant, it is not easy to clean, the processing time is long, and the efficiency is low. The advantage of the corundum wire cutting process is high processing efficiency, but due to the low strength of the produced slices, it is fragile and runs through the entire processing process of the germanium slices, which seriously affects the yield of the subsequent products. Due to the high value of germanium slices, a high fragmentation rate is unacceptable. Therefore, from the perspective of product cost and benefit, the free abrasive multi-wire cutting process is often used for germanium single crystal cutting.

[0003] The cutting oil used in the free abrasive multi-wire cutting process is mineral oil, which often faces the problem that the produced germanium slices adhere to the oil-based free abrasive containing germanium, and there are problems such as complex cleaning process, long processing time and low processing efficiency. Therefore, the present invention develops a new type of cutting oil, which is mixed with SiC and other abrasives to cut germanium single crystals, making the produced germanium slices easy to clean, thereby improving processing efficiency and processing quality. Summary of the invention

[0004] The germanium slices produced by the existing free abrasive wire cutting process are not easy to clean, and the processing process is complicated and inefficient. The present invention provides a cutting fluid for free abrasive multi-wire cutting, a preparation method and an application thereof, which reduces the difficulty of cleaning germanium slices.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] A cutting fluid for free abrasive multi-wire cutting comprises the following components by weight percentage: 35-55% of trimethylolpropane oleate, 15-35% of isooctyl stearate, 10-25% of isooctyl ester, 0.5-1% of sodium petroleum sulfonate, 0.2-1% of dibutyl hydroxytoluene, 5-15% of 25% sodium metasilicate solution and 0.2-1% of fatty alcohol polyoxyethylene ether.

[0007] The sum of the masses of the components is equal to 100%. 25% sodium metasilicate solution refers to a sodium metasilicate aqueous solution with a mass concentration of 25%.

[0008] The present invention does not need to add mineral oil or the like, and can form a uniform and stable cutting fluid through the selection and matching of specific components. The synergistic coordination between the components ensures the lubricating cutting effect and the strength of the germanium sheet, and facilitates cleaning.

[0009] During the research and development process, the inventors found that the selection of the above components is critical. If the fatty alcohol polyoxyethylene ether is replaced by Tween-20 or others, the cleaning effect will be worse, and it will also have a certain impact on the strength; if the sodium metasilicate solution is replaced by water or others, the fragments will be larger; if the sodium petroleum sulfonate is removed or replaced, the crushing rate will also increase; if other components are changed, the cleaning effect will also be affected.

[0010] As a further preferred embodiment, the cutting fluid for free abrasive multi-wire cutting comprises the following components by weight percentage: 40-50% of trimethylolpropane oleate, 30-35% of isooctyl stearate, 15-20% of isooctyl stearate, 0.5-0.8% of sodium petroleum sulfonate, 0.5-0.8% of butylated hydroxytoluene, 8-12% of 25% sodium metasilicate solution and 0.5-0.8% of fatty alcohol polyoxyethylene ether.

[0011] In order to further extend the service life of the cutting fluid and ensure the cutting effect, the isooctyl ester is isooctyl acetate or isooctyl oleate.

[0012] The preparation method of the above-mentioned free abrasive multi-wire cutting cutting fluid is as follows: 35-55% of trimethylolpropane oleate, 25-35% of isooctyl stearate, 10-25% of isooctyl stearate, 0.5-1% of sodium petroleum sulfonate, 0.5-1% of butylated hydroxytoluene, 5-15% of 25% sodium metasilicate solution and 0.2-1% of fatty alcohol polyoxyethylene ether are mixed evenly to obtain the free abrasive multi-wire cutting cutting fluid.

[0013] When the above-mentioned free abrasive multi-wire cutting cutting fluid is used, it is mixed with silicon carbide and used for multi-wire cutting of germanium single crystal.

[0014] The mass ratio of the above-mentioned free abrasive multi-wire cutting cutting fluid to silicon carbide is (5-6):5.

[0015] The fineness of the above silicon carbide is 3000-6000 mesh.

[0016] After the germanium slices are cut by multi-wire cutting of germanium single crystal, they are ultrasonically cleaned with water for 10-15 minutes, taken out, rinsed with water for 15-20 seconds, and dried, so that the surface is bright and clean.

[0017] The above cutting fluids also have a reinforcing effect.

[0018] The technologies not mentioned in the present invention are all referred to the prior art.

[0019] The cutting fluid for free abrasive multi-wire cutting of the present invention is applied to multi-wire cutting of germanium single crystals. After the obtained germanium slices are soaked and rinsed in clean water, clean germanium slices can be obtained, which eliminates the cumbersome steps of kerosene soaking and special cleaning agent cleaning in the original process, shortens the process flow, improves production efficiency, and reduces costs; the preparation is simple, the operation is easy, and the industrialization promotion is easy. DETAILED DESCRIPTION

[0020] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0021] Example 1

[0022] According to the weight percentage: 45% of trimethylolpropane oleate, 30% of isooctyl stearate, 15% of isooctyl oleate, 0.5% of sodium petroleum sulfonate (model T702, manufacturer: Jinan Jinyu Chemical Co., Ltd.), 0.5% of dibutyl hydroxytoluene, 8.5% of 25% sodium metasilicate aqueous solution (prepared from sodium metasilicate pentahydrate), 0.5% of fatty alcohol polyoxyethylene ether (model MOA-7, manufacturer: Jiangsu Hai'an Petrochemical Plant), mix well (stir at 100r / min for 5min), and test its kinematic viscosity to be 7.3mm 2 / s (50℃), suspension rate 93%, and stability at room temperature greater than 36 months.

[0023] 60kg of new cutting oil was mixed with 50kg of silicon carbide (4000 mesh) and then used for multi-wire cutting of germanium single crystal. The cut germanium slices were cleaned with deionized water for 15 minutes by ultrasonic (power 7200W, frequency 28HZ) (no need to add cleaning agent). The dirty surface of the germanium slices was put into the clean water, taken out, rinsed with water for 15 seconds, and dried. The surface of the germanium slices was bright, clean and transparent, without bright spots and white fog, with a qualified rate of 100% and a fragment rate of 0. The average strength of this batch of germanium slices (thickness 350um) was tested to be 2.3lbf.

[0024] Compared with mineral oil-based free mortar cutting, the cleaning time is saved by about 30 minutes and the strength is increased by 26.3%.

[0025] Example 2

[0026] According to the weight percentage: 40% trimethylolpropane oleate, 35% isooctyl stearate, 12.5% ​​isooctyl oleate, 1% sodium petroleum sulfonate (model T702, manufacturer: Jinan Jinyu Chemical Co., Ltd.), 1% dibutyl hydroxytoluene, 10% 25% sodium metasilicate aqueous solution (prepared from sodium metasilicate pentahydrate), 0.5% fatty alcohol polyoxyethylene ether (model MOA-7, manufacturer: Jiangsu Hai'an Petrochemical Plant), mix well (stir at 100r / min for 5min), and test its kinematic viscosity to be 6.9mm 2 / s (50℃), suspension rate 85%, and stability at room temperature greater than 36 months.

[0027] 60kg of new cutting oil was mixed with 50kg of silicon carbide (4000 mesh) and then used for multi-wire cutting of germanium single crystal. The cut germanium slices were soaked in deionized water for 13 minutes of ultrasound (power 7200W, frequency 28HZ) (no need to add cleaning agent). The dirty surface of the germanium slices was put into the clean water, taken out, rinsed with water for 15 seconds, and dried. The surface of the germanium slices was bright, clean and translucent, with a qualified rate of 100% and a fragmentation rate of 0. The average strength of this batch of germanium slices (thickness 350um) was tested to be 2.1bf.

[0028] Compared with mineral oil-based free sand mortar cutting, the cleaning time was saved by about 32 minutes and the strength was increased by 16.7%.

[0029] Example 3

[0030] According to the weight percentage: 55% of trimethylolpropane oleate, 15% of isooctyl stearate, 15% of isooctyl oleate, 0.8% of sodium petroleum sulfonate (model T702, manufacturer: Jinan Jinyu Chemical Co., Ltd.), 0.2% of dibutyl hydroxytoluene, 13% of 25% sodium metasilicate aqueous solution (prepared from sodium metasilicate pentahydrate), 1% of fatty alcohol polyoxyethylene ether (model MOA-7, manufacturer: Jiangsu Hai'an Petrochemical Plant), mix well (stir at 100r / min for 5min), and test its kinematic viscosity to be 7.9mm 2 / s (50℃), suspension rate 98%, and stability at room temperature greater than 36 months.

[0031] 60kg of new cutting oil was mixed with 50kg of silicon carbide (4000 mesh) and then used for multi-wire cutting of germanium single crystal. The cut germanium slices were cleaned with deionized water for 17 minutes by ultrasonic (power 7200W, frequency 28HZ) (no need to add cleaning agent). The dirty surface of the germanium slices was put into the clean water, taken out, rinsed with water for 15 seconds, and dried. The surface of the germanium slices was bright, clean and translucent, with a qualified rate of 100% and a fragment rate of 0. The average strength of this batch of germanium slices (thickness 350um) was tested to be 2.0lbf.

[0032] Compared with mineral oil-based free sand mortar cutting, the cleaning time was saved by about 28 minutes and the strength was increased by 11.1%.

[0033] Example 4

[0034] The difference from Example 1 is that isooctyl oleate is replaced by isooctyl acetate, and the rest is the same as Example 1. The average strength of the obtained germanium sheet is tested to be 2.1 lbf.

[0035] Comparative Example 1

[0036] The difference from Example 1 is that the fatty alcohol polyoxyethylene ether is replaced by Tween-20. The rest is the same as Example 1. After cleaning in the same method and time as Example 1, white fog appears on the surface of the germanium sheet, and the strength is tested to be 1.8 lbf.

[0037] Comparative Example 2

[0038] The difference from Example 1 is that the sodium metasilicate solution is replaced by pure water. The rest is the same as Example 1. After cutting in the same way as Example 1, the fragments are serious, and the germanium fragment rate reaches 8%.

[0039] Comparative Example 3

[0040] The difference from Example 1 is that all isooctyl oleate is replaced by isooctyl stearate. The rest is the same as Example 1. After cutting in the same way as Example 1, the fragmentation rate is high, and the fragmentation rate of the germanium sheet reaches 5%.

[0041] Comparative Example 4

[0042] The difference from Example 1 is that all the sodium petroleum sulfonate is replaced by fatty alcohol polyoxyethylene ether. The rest is the same as Example 1. After cutting in the same way as Example 1, the fragments are serious, and the fragment rate of the germanium sheet reaches 6%.

[0043] Comparative Example 5

[0044] The difference from Example 1 is that butylated hydroxytoluene is replaced by tris(2,4-di-tert-butylphenyl) phosphite. The rest is the same as Example 1. After cleaning in the same method and time as Example 1, a lot of dirt remains on the surface of the germanium sheet, which is not easy to clean.

Claims

1. A cutting fluid for free abrasive multi-wire cutting, characterized in that: The invention comprises the following components by weight percentage: 35-55% of trimethylolpropane oleate, 15-35% of isooctyl stearate, 10-25% of isooctyl ester, 0.5-1% of sodium petroleum sulfonate, 0.2-1% of butylated hydroxytoluene, 5-15% of 25% sodium metasilicate solution and 0.2-1% of fatty alcohol polyoxyethylene ether.

2. The cutting fluid for free abrasive multi-wire cutting according to claim 1, characterized in that: The invention comprises the following components by weight percentage: 40-50% of trimethylolpropane oleate, 30-35% of isooctyl stearate, 15-20% of isooctyl ester, 0.5-0.8% of sodium petroleum sulfonate, 0.5-0.8% of dibutyl hydroxytoluene, 8-12% of 25% sodium metasilicate solution and 0.5-0.8% of fatty alcohol polyoxyethylene ether.

3. The cutting fluid for free abrasive multi-wire cutting according to claim 1 or 2, characterized in that: The isooctyl ester is isooctyl acetate or isooctyl oleate.

4. A method for preparing a cutting fluid for free abrasive multi-wire cutting according to any one of claims 1 to 3, characterized in that: 35-55% of trimethylolpropane oleate, 25-35% of isooctyl stearate, 10-25% of isooctyl ester, 0.5-1% of sodium petroleum sulfonate, 0.5-1% of dibutyl hydroxytoluene, 5-15% of 25% sodium metasilicate solution and 0.2-1% of fatty alcohol polyoxyethylene ether are uniformly mixed to obtain a cutting fluid for free abrasive multi-wire cutting.

5. Use of the free abrasive multi-wire cutting cutting fluid according to any one of claims 1 to 3, characterized in that: The free abrasive multi-wire cutting cutting fluid is mixed with silicon carbide and used for multi-wire cutting of germanium single crystal.

6. The use of the free abrasive multi-wire cutting cutting fluid according to claim 5, characterized in that: The mass ratio of cutting fluid to silicon carbide for free abrasive multi-wire cutting is (5-6):

5.

7. Use of the free abrasive multi-wire cutting cutting fluid according to claim 5 or 6, characterized in that: The fineness of silicon carbide is 3000-6000 mesh.

8. Use of the free abrasive multi-wire cutting cutting fluid according to claim 5 or 6, characterized in that: After multi-wire cutting of germanium single crystal, the germanium slice is ultrasonically cleaned with water for 10-15 minutes, taken out, rinsed with water for 15-20 seconds, and dried, so that the surface is bright and clean.