Cutting fluid for carborundum wire cutting of silicon wafer

Abstract

The invention relates to the field of semiconductor manufacturing processes, and provides a cutting fluid for carborundum wire cutting of a silicon wafer, the cutting fluid comprises the following components in parts by weight: 10-20 parts of propylene glycol, 10-20 parts of polyether, 3-10 parts of a lubricant, 5-10 parts of triethanolamine, 5-10 parts of alkynol and 40-60 parts of pure water, the pure water is sequentially added into the propylene glycol, the polyether, the lubricant, the triethanolamine and the alkynol at normal temperature, the mixture is stirred uniformly, and the cutting fluid is obtained. By adding the lubricant with better hydrophilicity into the cutting fluid, the cutting fluid can quickly wet a diamond wire and a silicon wafer, the decline speed of the diamond wire cutting capability is obviously reduced, the wire breaking abnormity in the cutting process is reduced, the smooth cutting operation is ensured, and meanwhile, the cutting fluid has high hydrophilicity and is convenient to use. The problem of poor dispersion of impurity particles such as silicon powder and silicon carbide is solved, and high cutting quality of silicon wafers is ensured by quickly spreading, wetting and dispersing the impurities.

Description

Technical Field

[0001] The invention relates to the field of semiconductor manufacturing technology, and in particular to a cutting fluid used for diamond wire cutting of silicon wafers. Background Art

[0002] At present, with the increasing awareness of environmental protection and the increasingly serious energy problem, various clean energy sources are attracting more and more attention. Among them, solar energy, with its advantages of being pollution-free, renewable, and non-regional, will inevitably be favored by all walks of life, and the solar energy industry will also develop rapidly. As the basic component of solar power generation, the slicing process of silicon wafers will inevitably occupy an important position.

[0003] In the processing of silicon wafers, cutting is a key link. Although traditional silicon wafer cutting fluid can meet the cutting needs to a certain extent, there are often some problems, such as low cutting efficiency, poor silicon wafer surface quality, and difficult to clean cutting fluid residue. These problems not only affect the yield and production efficiency of silicon wafers, but may also have adverse effects on subsequent processes and product performance.

[0004] Therefore, the silicon wafer cutting fluid in the prior art has the following problems:

[0005] 1. The wettability and dispersibility of traditional cutting fluids are poor, which increases the friction resistance between the diamond wire and the silicon wafer contact surface and reduces the cutting efficiency.

[0006] 2. Certain components in the cutting fluid may react with the surface of the silicon wafer during the cutting process, forming residues that are difficult to remove, affecting the cleanliness and smoothness of the silicon wafer surface.

[0007] 3. Some components in the cutting fluid have poor water solubility, resulting in difficult-to-clean residues on the surface of the silicon wafer after cutting, which increases the difficulty and cost of the subsequent cleaning process.

[0008] 4. The cutting fluid contains toxic or harmful ingredients, which pose a threat to the environment and the health of operators. At the same time, these ingredients may also increase the difficulty and cost of treatment during wastewater treatment. Summary of the invention

[0009] The present invention provides a cutting liquid for diamond wire cutting of silicon wafers, which solves the problem in the related art that residues which are difficult to clean are formed on the surface of the silicon plate after cutting is completed.

[0010] The technical solution of the present invention is as follows:

[0011] To achieve the above object, the present invention provides the following technical solution: a cutting fluid for diamond wire cutting of silicon wafers, the production process comprising the following steps: 10 to 20 parts of propylene glycol, 10 to 20 parts of polyether, 3 to 10 parts of lubricant, 5 to 10 parts of triethanolamine, 5 to 10 parts of acetylene alcohol and 40 to 60 parts of pure water;

[0012] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0013] Preferably, the lubricant is a multifunctional synthetic ester lubricant having a turbidity point of 45 degrees and a water-oil ratio of 7, so that the lubricant has good hydrophilicity, and the residue on the surface of the silicon wafer after cutting is more easily washed away by water, which helps to reduce the difficulty and cost of subsequent cleaning processes and ensure the cleanliness of the silicon wafer surface.

[0014] Preferably, the polyether is a block polyether with a cloud point of 75 degrees and a water-oil ratio of 13.5, which can be better dispersed in the cutting fluid and form a stable system with other components in the cutting fluid, which helps to reduce precipitation and stratification in the cutting fluid, improve the stability and service life of the cutting fluid, and be more environmentally friendly.

[0015] Preferably, in the mixing step, the stirring rate is 200-400 rpm and the stirring time is 20-60 minutes. Using a lower rotation speed can reduce bubbles generated during the stirring process and can reduce turbulence and vibration during the cutting process.

[0016] Preferably, after the mixing step, a homogenization step is also included to further improve the stability and dispersibility of the cutting fluid.

[0017] Preferably, the homogenization step is to homogenize the mixed liquid by a high-pressure homogenizer at a homogenization pressure of 30 to 70 MPa, and repeat the homogenization 2 to 5 times, which can ensure that the components in the mixed liquid are more evenly distributed. This helps to form a stable lubricating film, improve cutting efficiency, and reduce friction and heat generation during the cutting process.

[0018] Preferably, the pure water is deionized water or distilled water.

[0019] Preferably, a cutting fluid for diamond wire sawing of silicon wafers is a product prepared by the above production process.

[0020] The working principle and beneficial effects of the present invention are:

[0021] 1. The present invention adds a lubricant with good hydrophilicity inside, so that the cutting fluid can quickly wet the diamond wire and silicon wafer, effectively play the role of lubrication, cooling and protection, significantly reduce the decay rate of the diamond wire cutting ability, reduce abnormal wire breakage during the cutting process, and ensure the smooth progress of the cutting operation. At the same time, the high hydrophilicity solves the problem of poor dispersion of impurity particles such as silicon powder and silicon carbide, and quickly spreads, wets and disperses these impurities, ensuring the high cutting quality of the silicon wafer.

[0022] 2. The present invention significantly reduces the chemical oxygen demand of the cutting fluid after mixing and forming by adding a lubricant with a lower molecular weight inside, which means that the organic matter content inside the cutting fluid is lower, which helps to reduce wastewater treatment costs and environmental pollution and increase environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0024] Figure 1 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 1;

[0025] Figure 2 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 2;

[0026] Figure 3 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 3;

[0027] Figure 4 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 4;

[0028] Figure 5 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 5;

[0029] Figure 6 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 6;

[0030] Figure 7 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 7;

[0031] Figure 8 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 8;

[0032] Fig. 9 This is a picture of a finished silicon wafer cut using the cutting fluid prepared in Example 9. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that the two lubricants used in the following examples are Priolube 3955 from Croda and 465 from Evonik Specialty Chemicals, and the two polyethers used are CA-60 from Dow Chemical and RP1740 from BASF Chemicals.

[0035] Embodiment 1:

[0036] The cutting fluid is composed of 12 parts of propylene glycol, 13 parts of 465 polyether, 3 parts of RP1740 lubricant, 6 parts of triethanolamine, 6 parts of acetylene alcohol and deionized water, calculated by weight fraction;

[0037] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0038] Embodiment 2:

[0039] The cutting fluid is composed of 13 parts of propylene glycol, 10 parts of 465 polyether, 5 parts of RP1740 lubricant, 7 parts of triethanolamine, 5 parts of acetylene alcohol and deionized water, calculated by weight fraction;

[0040] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0041] Embodiment three:

[0042] The cutting fluid is composed of 15 parts of propylene glycol, 12 parts of 465 polyether, 5 parts of RP1740 lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and deionized water, calculated by weight fraction;

[0043] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0044] Embodiment 4:

[0045] The cutting fluid is composed of 15 parts of propylene glycol, 12 parts of 465 polyether, 5 parts of lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and deionized water, and the lubricant is Priolube3955.

[0046] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0047] Embodiment five:

[0048] The cutting fluid is composed of 15 parts of propylene glycol, 12 parts of 465 polyether, 7.5 parts of lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and deionized water, and the lubricant is Priolube3955.

[0049] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0050] Embodiment six:

[0051] The cutting fluid is composed of 15 parts of propylene glycol, 12 parts of 465 polyether, 10 parts of lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and deionized water, and the lubricant is Priolube3955.

[0052] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0053] Embodiment seven:

[0054] The cutting fluid is composed of 15 parts of propylene glycol, 12 parts of polyether, 10 parts of lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and deionized water. In terms of weight fraction, CA-60 is selected for polyether and Priolube3955 is selected for lubricant.

[0055] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0056] Embodiment eight:

[0057] The cutting fluid is composed of 15 parts of propylene glycol, 5 parts of polyether, 10 parts of lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and deionized water. In terms of weight fraction, CA-60 is selected for polyether and Priolube3955 is selected for lubricant.

[0058] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0059] Embodiment nine:

[0060] The cutting fluid is composed of 15 parts of propylene glycol, 10 parts of polyether, 10 parts of lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and deionized water. In terms of weight fraction, CA-60 is selected for polyether and Priolube3955 is selected for lubricant.

[0061] Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

[0062] Table 1 Preparation parameters of cutting fluids of Examples 1 to 9

[0063]

[0064]

[0065] According to the following test method, the cutting fluid obtained in Examples 1 to 9 was used to build a bath at a weight ratio of 8:1000, and silicon wafer cutting was carried out online, 4 cuts were made, and the total number of wafers cut was 10,000, and the test results were shown in Table 2. The specific method is as follows:

[0066] (1) Surface tension mN / m

[0067] The surface tension of the cutting fluids prepared in Examples 1-9 was measured by using a surface tension meter BZY-1A. By testing the surface tension, it can be seen that lower surface tension means better wettability and spreadability. This helps the cutting fluid to form a uniform film between the silicon wafer surface and the diamond wire, thereby effectively playing a role in lubrication, cooling and protection.

[0068] (2) Dispersibility

[0069] Based on the measured surface tension, we can judge whether the dispersion is excellent. Good dispersion can ensure that these particles will not agglomerate into blocks during the cutting process, thereby avoiding damage to the diamond wire and silicon wafer. Cutting fluids with good dispersion can effectively reduce line marks and surface defects during the cutting process and improve the cutting quality of silicon wafers.

[0070] (3) Chemical oxygen demand (COD)

[0071] The chemical oxygen demand of the cutting fluids prepared in the above Examples 1-9 was tested by using a COD detector SH-200. For silicon wafer cutting fluids, a lower COD value means a lower organic matter content, which helps to reduce wastewater treatment costs and environmental pollution.

[0072] (4) Line marks

[0073] By visually inspecting the surface of the silicon wafer after cutting, we can observe the line marks on the surface. Line marks are one of the key factors affecting the quality of silicon wafers. Too many line marks will lead to increased surface roughness and uneven thickness of the silicon wafer.

[0074] (5) Yield

[0075] By counting the silicon wafers after cutting and comparing the yield of good products and the total yield, the formula is as follows:

[0076] Good products / total quantity=yield rate (Formula 1).

[0077] The various properties of the cutting fluids of Examples 1 to 9 are shown in Table 2:

[0078]

[0079]

[0080] The test results are shown in Table 2. It can be seen that the cutting fluid of Example 9 of the present invention has better cutting performance data than the cutting fluids of Comparative Examples 1 to 8 under the same cutting process conditions, and has a strong dispersion effect, so the corresponding silicon wafer cutting effect is good;

[0081] Further, the chemical oxygen demand of the cutting fluid of Example 9 is only 680,000, which is the lowest among Examples 1 to 9. The lower COD indicates that the organic matter content in the cutting fluid is lower, which helps to reduce the wastewater treatment cost and the pollution to the environment, and can meet the environmental protection requirements in industrial production;

[0082] Most importantly, the cutting fluid of Example 9 achieved a high yield of 97.7% during the silicon wafer cutting process, which means that the use of this cutting fluid can greatly improve the yield of silicon wafers, reduce production costs, and increase the economic benefits of the enterprise. In addition, the cutting fluid of Example 9 produced the least line marks, indicating that the cutting fluid can effectively reduce scratches and damage on the surface of silicon wafers and improve the yield and quality of silicon wafers.

[0083] In summary, the optimal ratio of this cutting fluid is 15 parts of propylene glycol, 10 parts of CA-60 polyether, 10 parts of Priolube3955 lubricant, 5 parts of triethanolamine, 7 parts of acetylene alcohol and 50 parts of deionized water, which can improve the yield and cutting quality of silicon wafers while ensuring environmental protection.

[0084] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cutting fluid for diamond wire cutting of silicon wafers, characterized in that: The composition includes the following components by weight: 10-20 parts of propylene glycol, 10-20 parts of polyether, 3-10 parts of lubricant, 5-10 parts of triethanolamine, 5-10 parts of acetylene alcohol and 40-60 parts of pure water; Propylene glycol, polyether, lubricant, triethanolamine and acetylene alcohol are sequentially added into pure water at room temperature and stirred until the mixture is uniform and transparent to obtain the cutting fluid.

2. The production process of the cutting fluid for diamond wire sawing of silicon wafers according to claim 1, characterized in that: The lubricant is a multifunctional synthetic ester lubricant with a cloud point of 45 degrees and a water-oil value of 7.

3. The production process of the cutting fluid for diamond wire sawing of silicon wafers according to claim 1, characterized in that: The polyether is a block polyether, the cloud point of which is 75 degrees, and the water-oil ratio is 13.

5.

4. The production process of the cutting fluid for diamond wire sawing of silicon wafers according to claim 1, characterized in that: In the mixing step, the stirring rate is 200 to 400 rpm, and the stirring time is 20 to 60 minutes.

5. The production process of the cutting fluid for diamond wire sawing of silicon wafers according to claim 1, characterized in that: After the mixing step, a homogenization step is also included to further improve the stability and dispersibility of the cutting fluid.

6. The production process of the cutting fluid for diamond wire sawing of silicon wafers according to claim 6, characterized in that: The homogenization step is to homogenize the mixed liquid through a high-pressure homogenizer, the homogenization pressure is 30-70 MPa, and the homogenization is repeated 2-5 times.

7. The production process of the cutting fluid for diamond wire sawing of silicon wafers according to claim 1, characterized in that: The pure water is deionized water or distilled water.

8. The cutting fluid prepared according to any one of claims 1 to 8, wherein the cutting fluid is used for diamond wire sawing of silicon wafers.

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