A new wetting agent for silicon wafer cutting, its preparation method and application

Abstract

This invention discloses a novel wetting agent for silicon wafer dicing, its preparation method, and its applications. The main component of this wetting agent is sodium 3,5,5-trimethylhexanol succinate sulfonate. The specific preparation method includes: first, reacting 3,5,5-trimethylhexanol with maleic anhydride at a certain temperature, adding p-toluenesulfonic acid as a catalyst, removing oxygen by nitrogen displacement, then heating and maintaining the temperature for a period of time, and finally removing byproducts under reduced pressure. Second, mixing the obtained product with ethanol and sodium hydroxide, heating to a specific temperature, adding a sodium metabisulfite aqueous solution of a specific concentration dropwise, maintaining the temperature for a certain time, and finally cooling and adding more ethanol to obtain the final product. This wetting agent exhibits excellent wetting performance during silicon wafer dicing, effectively reducing dicing marks, lowering surface roughness, and improving dicing efficiency and silicon wafer quality. Furthermore, this wetting agent has broad application prospects in wafer cleaning, photolithography, photovoltaic industry, electronic packaging, and MEMS device manufacturing, possessing significant market potential and commercial value.

Description

Technical Field

[0001] This invention relates to the field of flux coating technology, and in particular to a novel wetting agent for silicon wafer cutting, its preparation method and application. Background Technology

[0002] Silicon wafers are the fundamental material for manufacturing solar cells. With the rapid growth in demand for solar cells, silicon wafers also have a very broad market demand. Currently, diamond wire cutting has completely replaced traditional slurry cutting as the mainstream cutting process, with a production capacity 5-8 times that of slurry cutting. Wetting agents are needed during wafer slicing to ensure the flatness of the silicon wafer surface and prevent diamond wire breakage. However, existing wetting agents have the following problems:

[0003] Poor wetting performance: The wetting agent cannot effectively cover the silicon wafer surface or form a uniform wetting film, resulting in a decrease in cutting quality.

[0004] Residue: Wetting agent residue left after cutting may affect subsequent processing steps or the electrical properties of the product.

[0005] Biocontamination: Wetting agents may become the basis for microbial growth, causing biocontamination problems.

[0006] Compatibility issues: Incompatibility between wetting agents and other process chemicals or materials may lead to product quality problems or equipment malfunctions.

[0007] Environmental and safety concerns: Some wetting agents may contain harmful chemicals that pose potential risks to operators and the environment.

[0008] The cleanliness of the silicon wafer surface is also one of the key factors affecting the yield of silicon wafers. During cutting, traditional wetting agents do not have a strong enough wetting effect on the silicon powder on the silicon wafer surface. Summary of the Invention

[0009] The wetting agent of this invention is characterized by low foaming, rapid wetting, low cost, high cutting efficiency, and reduced cutting marks. It also has a certain effect on removing and suspending silicon powder, thus effectively solving the problem of residual silicon powder on the silicon wafer surface causing cutting marks during cutting. The wetting agent of this invention plays a certain role in removing and suspending silicon powder on the silicon wafer surface during cutting, thereby reducing the pressure on subsequent silicon wafer polishing and cleaning and improving the biodegradability of wastewater.

[0010] This invention provides a novel wetting agent that uses sodium 3,5,5-trimethylhexanol succinate sulfonate as the main component.

[0011] The structural formula of sodium 3,5,5-trimethylhexanol succinate sulfonate is shown in Figure I:

[0012]

[0013] The preparation process of the wetting agent described in this invention is as follows:

[0014] (1) 3,5,5-trimethylhexanol reacts with maleic anhydride at a certain temperature, a protic acid catalyst is added, the temperature is raised and maintained for a period of time under inert gas conditions, and finally the byproducts are removed under reduced pressure.

[0015] (2) The product obtained in step (1) is mixed with an alcohol solvent and sodium hydroxide, heated, and then sodium metabisulfite aqueous solution is added dropwise. The mixture is kept warm for a certain period of time, and finally cooled and ethanol is added to obtain the final product.

[0016] For the technical solution described above, a further preferred embodiment is that the protic acid catalyst in step (1) is selected from one or more of sulfuric acid, p-toluenesulfonic acid, tungstic acid, and nitric acid.

[0017] For the technical solution described above, a further preferred embodiment is that after adding the protic acid catalyst in step (1), its concentration in the reaction system is 0.2-5 wt%; a more preferred ratio is 0.5-1 wt%.

[0018] For the technical solution described above, a further preferred embodiment is that the weight ratio of 3,5,5-trimethylhexanol to maleic anhydride in step (1) is 2.2-3.5:1; more preferably, a ratio of 3-3.1:1 is used.

[0019] For the technical solution described above, a further preferred embodiment is that the inert gas in step (1) is nitrogen.

[0020] For the technical solution described above, a further preferred embodiment is p-toluenesulfonic acid, which is the protic acid catalyst in step (1).

[0021] For the technical solution described above, a further preferred embodiment is that the pressure reduction condition in step (1) is no greater than -0.085 MPa; more preferably, the pressure reduction condition is no greater than -0.09 MPa.

[0022] For the technical solution described above, a further preferred embodiment is that the heating temperature in step (1) is 70-140℃; more preferably, it is 80-120℃.

[0023] For the technical solution described above, a further preferred embodiment is that the temperature is maintained for 2-5 hours after the heating in step (1).

[0024] For the technical solution described above, a further preferred embodiment is that the concentration range of the sodium metabisulfite aqueous solution in step (2) is 30-70 wt%, and a more preferred range is 33-67 wt%.

[0025] For the technical solution described above, a further preferred option is that the alcohol solvent in step (2) is selected from one or more of methanol, ethanol, and isopropanol.

[0026] For the technical solution described above, a further preferred embodiment is that the weight ratio of the product obtained in step (1), the alcohol solvent, and the sodium hydroxide is (50-200):(3-10):1; more preferably, the weight ratio of the product, alcohol solvent, and sodium hydroxide in step (1) is (138-170):(4.38-5):1.

[0027] For the technical solution described above, a further preferred option is that the heating temperature range in step (2) is 40-100℃, and a more preferred heating temperature range is 80-100℃.

[0028] For the technical solution described above, a further preferred embodiment is that the amount of sodium metabisulfite aqueous solution added in step (2) is 0.25-0.67 times the weight of the product obtained in step (1); more preferably, the amount of sodium metabisulfite aqueous solution added is 0.28-0.32 times the weight of the product obtained in step (1).

[0029] For the technical solution described above, a further preferred embodiment is that the cooling and adding more ethanol in step (2) is: the temperature is reduced to 50-80℃; more preferably, the temperature should be 60-70℃; the amount of ethanol added is 0.02-0.2 times the weight of the product obtained in step (1); more preferably, the amount of ethanol added is 0.02-0.1 times the weight of the product obtained in step (1).

[0030] Another aspect of the present invention is to protect the application of the aforementioned wetting agent, including but not limited to:

[0031] In semiconductor manufacturing, it can effectively reduce silicon wafer dicing marks, improve dicing efficiency and surface quality, and enhance cleanliness in wafer cleaning and photolithography processes.

[0032] In the photovoltaic industry, this wetting agent can be used for cleaning and etching solar cells, improving cell cleanliness and thus increasing cell yield and photoelectric conversion efficiency.

[0033] In electronic packaging and MEMS device manufacturing, it improves the adhesion and bonding strength of materials, thereby enhancing the reliability and precision of devices.

[0034] It performs particularly well as a wetting additive used in silicon wafer cutting.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] By optimizing reaction conditions, this invention enables the reaction to be completed in a shorter time, thereby improving production efficiency.

[0037] By precisely controlling the reaction conditions and post-processing steps, the sodium 3,5,5-trimethylhexanol succinate sulfonate prepared by this invention has higher purity and more stable properties, making it suitable for producing wetting agents for high-performance silicon wafer cutting.

[0038] By using more economical raw materials and catalysts, as well as optimized reaction conditions, this invention reduces production costs and improves economic efficiency.

[0039] The catalysts and solvents used in this invention are environmentally friendly, reducing the emission of harmful substances and meeting the requirements of green chemistry.

[0040] The wetting agent prepared by this invention exhibits excellent wetting performance during silicon wafer dicing, effectively reducing dicing marks, decreasing surface roughness, and improving dicing efficiency and silicon wafer quality.

[0041] The wetting agent prepared by this invention produces less foam and has good foam stability during use, which helps to improve the stability and reliability of the processing.

[0042] The wetting agent prepared by this invention has good silicon powder suspension ability, which can effectively prevent silicon powder sedimentation and ensure the uniformity and stability of the cutting fluid.

[0043] The wetting agent of the present invention has the characteristics of low foaming, fast wetting, low cost, high cutting efficiency, and reduced cutting marks. It also has a certain effect on the peeling and suspension of silicon powder, thereby effectively solving the problem of marks caused by residual silicon powder on the surface of silicon wafers during cutting.

[0044] The wetting agent of this invention has a certain peeling and suspending effect on the silicon powder on the surface of the silicon wafer during cutting, thereby reducing the pressure of subsequent silicon wafer polishing and cleaning and improving the biodegradability of wastewater.

[0045] The wetting agent prepared by this invention is not only applicable to silicon wafer cutting, but can also be extended to the processing of other semiconductor materials, thus having wider applicability and market prospects.

[0046] The preparation method of the present invention is simple and easy to implement, with clear operation steps, which facilitates industrial production and quality control. Attached Figure Description

[0047] Figure 1 The NMR spectrum, shown in the image, is the NMR result of sodium 3,5,5-trimethylhexanol succinate sulfonate, proving that the structure is consistent.

[0048] Figure 2. Surface tension diagram, where A, B, C, and D show the wetting speed test of the wetting agent prepared using Examples 1-3 of the present invention, and D shows the wetting speed test of the commercially available wetting agent (the wetting agent Fast T described in Example 4).

[0049] Figure 3. Schematic diagram of the surface marks on the silicon wafer after cutting. A, B, C, and D show the microscopic images of silicon wafers after cutting with the wetting agent prepared in Examples 1-3 of this invention, and D shows the microscopic image of silicon wafers after cutting with the commercially available wetting agent (the wetting agent Fast T described in Example 4). Detailed Implementation

[0050] The present invention will be further described below with reference to the embodiments, but it should be understood that the scope of protection of the present invention is not limited to the embodiments.

[0051] The sodium metabisulfite aqueous solution in the examples is prepared as follows: 100-300g of sodium metabisulfite and 100-200g of deionized water are mixed to prepare a sodium metabisulfite aqueous solution with a concentration of 33.3-66.7wt%.

[0052] Example 1

[0053] (1) Take 300g of 3,5,5-trimethylhexanol, add 100g of maleic anhydride and 1g of p-toluenesulfonic acid at 40℃, replace with N2 twice, then slowly raise the temperature to 80℃ (1℃ / min) and keep it at that temperature for 2 hours. Then draw a vacuum of -0.09Mpa and maintain it for 3 hours. Take a sample and measure the acid value. If it is <3.5mgKOH / g, continue to draw a vacuum. After passing the test, cool to 50℃ and discharge the material.

[0054] (2) Add 400g of the product obtained in step (1) to a flask, add 10g of 90wt% ethanol and 2g of 48wt% NaOH solution. Stir for 15 minutes, heat to 60℃, and then add 160g of 33.3wt% sodium metabisulfite aqueous solution dropwise to the flask. After the addition is complete, keep warm at 70℃ for 2 hours, cool to 60℃, and then add 10g of 92wt% ethanol to obtain wetting agent 1 for silicon wafer cutting. The NMR detection results are as follows. Figure 1 It is mainly composed of sodium 3,5,5-trimethylhexanol succinate sulfonate, and its structural formula is shown in Figure I.

[0055]

[0056] Example 2

[0057] (1) Take 350g of 3,5,5-trimethylhexanol, add 150g of maleic anhydride and 3g of p-toluenesulfonic acid at 45℃, replace with N2 twice, then slowly raise the temperature to 100℃ (1℃ / min) and keep it at that temperature for 3 hours. Then draw a vacuum of -0.09Mpa and maintain it for 8 hours. Take a sample and measure the acid value. If it is <3.5mgKOH / g, continue to draw a vacuum. After passing the test, cool to 50℃ and discharge the material.

[0058] (2) Add 450g of the product obtained in step (1) to a flask, add 25g of 90wt% ethanol and 3g of 48wt% NaOH solution. Stir for 15 minutes, heat to 80℃, and then add 135g of 44wt% sodium metabisulfite aqueous solution dropwise to the flask. After the addition is complete, keep warm at 80℃ for 5 hours, cool down to 70℃ and then add 40g of 92wt% ethanol to obtain wetting agent 2 for silicon wafer cutting.

[0059] Example 3

[0060] (1) Take 370g of 3,5,5-trimethylhexanol, add 160g of maleic anhydride and 8g of p-toluenesulfonic acid at 45℃, replace with N2 twice, then slowly raise the temperature to 120℃ (1℃ / min) and keep it at that temperature for 4 hours. Then draw a vacuum of -0.09Mpa and maintain it for 15 hours. Take a sample and measure the acid value. If it is <3.5mgKOH / g, continue to draw a vacuum. After passing the test, cool to 50℃ and discharge the material.

[0061] (2) Add 550g of the product obtained in step (1) to a flask, add 35g of 90wt% ethanol and 8g of 48wt% NaOH solution. Stir for 15 minutes, heat to 100℃, and then add 192g of 50wt% sodium metabisulfite aqueous solution dropwise to the flask. After the addition is complete, keep it at 100℃ for 8 hours, cool it to 70℃, and then add 50g of 92wt% ethanol to obtain wetting agent 3 for silicon wafer cutting.

[0062] Comparative example. Traditional wetting agents

[0063] Use the commercially available wetting agent QuickT: the main component is diisooctyl maleate sulfonate (sodium dioctyl sulfosuccinate) as the wetting agent 4.

[0064] Application effect example 1

[0065] Wetting agents 1-4 were used for silicon wafer cutting, and their concentrations were prepared as 0.1 wt% aqueous solutions of wetting agents.

[0066] Performance testing

[0067] The following aspects will be used to demonstrate the experimental and data testing:

[0068] Foam stability test: measures the amount and duration of foam production during use.

[0069] Foam height test: Record the foam height under different conditions.

[0070] Contact angle measurement: The wetting performance of a wetting agent is evaluated by the change in the contact angle.

[0071] Wetting time: The time required for the wetting agent to completely wet the surface of the silicon wafer.

[0072] Reduced dicing marks test: Inspect the surface of the cut silicon wafer using an optical microscope or scanning electron microscope (SEM).

[0073] Surface roughness measurement: The surface roughness of the cut silicon wafer is measured using a surface roughness meter.

[0074] Evaluation indicators and test results

[0075]

[0076]

[0077] By comparing and analyzing the data from Examples 1-3 with Comparative Example 1, it is clear that the technical solution of the present invention exhibits significant advantages in multiple performance indicators. The following is a detailed analysis of each performance indicator:

[0078] Foam stability test:

[0079] Examples 1-3: Foam durations were 53 seconds, 50 seconds, and 56 seconds, respectively. Comparative Example 1: Foam duration was 43 seconds.

[0080] Although the foam duration of the present invention is slightly longer, the foam height is 1.3 times that of Comparative Example 1, which is 1.5 times that of Comparative Example 1.

[0081] This demonstrates that the wetting agent of the present invention performs better in controlling foam height, which helps to improve the stability and reliability of the processing.

[0082] Wetting performance test:

[0083] Contact angle: The contact angles of Examples 1-3 are 42°, 43° and 43° respectively, while that of Comparative Example 1 is 49°.

[0084] Time required to achieve complete wetting: Examples 1-3 were 30 seconds, 33 seconds and 35 seconds respectively, while Comparative Example 1 was 40 seconds.

[0085] This demonstrates that the wetting agent of the present invention is superior to Comparative Example 1 in both contact angle and wetting time, indicating that it has better wetting performance, can wet the silicon wafer surface more quickly, and improve cutting efficiency.

[0086] Cutting efficiency test:

[0087] The condition of the silicon wafer surface after cutting: Examples 1-3 all have "few lines", while Comparative Example 1 has "more lines".

[0088] Surface roughness of silicon wafers after dicing: Examples 1-3 were 0.36%, 0.34%, and 0.41%, respectively, while Comparative Example 1 was 0.7%.

[0089] This demonstrates that the wetting agent of the present invention exhibits significant advantages in reducing dicing marks and surface roughness, thereby contributing to improved silicon wafer quality and dicing efficiency.

[0090] Silicon powder exfoliation and suspension ability test:

[0091] Suspension stability: Although specific data are not provided, based on the performance of Comparative Example 1, the wetting agent of the present invention performs better in terms of silicon powder suspension ability, effectively preventing silicon powder sedimentation and ensuring the uniformity and stability of the cutting fluid.

[0092] This demonstrates that the wetting agent of the present invention can effectively disperse silicon powder, reduce the pressure of subsequent silicon wafer polishing and cleaning, and improve the biodegradability of wastewater.

[0093] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A process for preparing a wetting agent for silicon wafer dicing, characterized in that: Includes the following steps: (1) 3,5,5-trimethylhexanol reacts with maleic anhydride at a certain temperature, a protic acid catalyst is added, the temperature is raised and maintained for a period of time under inert gas conditions, and finally the byproduct is removed under reduced pressure; the weight ratio of 3,5,5-trimethylhexanol to maleic anhydride is 2.2-3.5:

1. (2) The product obtained in step (1) is mixed with an alcohol solvent and sodium hydroxide, heated, and then a sodium metabisulfite aqueous solution with a concentration of 30-70wt% is added dropwise. The mixture is kept warm for a certain period of time, and finally cooled to 50-80℃ and ethanol is added. The amount of ethanol added is 0.02-0.2 times the weight of the product obtained in step (1) to obtain the final product. In step (2), the amount of sodium metabisulfite aqueous solution added is 0.25 - 0.67 times the weight of the product obtained in step (1); The wetting agent is mainly composed of sodium 3,5,5-trimethylhexanol succinate sulfonate; the structural formula of sodium 3,5,5-trimethylhexanol succinate sulfonate is shown in Figure I:

2. The preparation process of the wetting agent according to claim 1, characterized in that: The protic acid catalyst in step (1) is selected from one or more of sulfuric acid, p-toluenesulfonic acid, tungstic acid, and nitric acid.

3. The preparation process of the wetting agent according to claim 1, characterized in that: After adding the protic acid catalyst in step (1), its concentration in the reaction system is 0.2-5 wt%.

4. The preparation process of the wetting agent according to claim 1, characterized in that: The heating temperature in step (1) is 70-140℃.

5. The preparation process of the wetting agent according to claim 1, characterized in that: The alcohol solvent in step (2) is selected from one or more of methanol, ethanol, and isopropanol.

6. The preparation process of the wetting agent according to claim 1, characterized in that: The weight ratios of the product obtained in step (1), the alcohol solvent, and the sodium hydroxide are (50 - 200): (3 - 10):

1.

7. The preparation process of the wetting agent according to claim 1, characterized in that: The heating temperature in step (2) is 40-100℃.

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