Semiconductor silicon wafer cutting fluid, preparation method and application thereof

Abstract

The application discloses a semiconductor silicon wafer cutting fluid and a preparation method and application thereof, and relates to the technical field of semiconductor silicon wafer cutting fluids.The semiconductor silicon wafer cutting fluid comprises polyethylene glycol, a dispersing agent, a surfactant, a defoaming agent and an additive.The semiconductor silicon wafer cutting fluid has no special requirement on a semiconductor silicon wafer cutting process, does not need a special treatment process, and can be mixed with silicon carbide, thereby being convenient to use.The semiconductor silicon wafer cutting fluid is environment-friendly, non-polluting and small in volatile loss, and after cutting, the silicon wafer can be washed only with pure water, thereby being harmless to the environment and human bodies.

Description

Technical Field

[0001] This invention relates to the field of semiconductor silicon wafer cutting technology, and more specifically, to semiconductor silicon wafer cutting fluid, its preparation method, and its application. Background Technology

[0002] Semiconductor silicon wafers are typically cut from silicon ingots. In the process of cutting silicon ingots into silicon wafers, the cutting medium needs to have the characteristics of high hardness, small particle size (6.5-24μm), and concentrated particle size distribution. Silicon carbide (with a hardness between corundum and diamond) is usually selected as the cutting medium. The micro powder of the cutting medium is added to an oil-soluble or water-soluble silicon wafer cutting fluid with polyethylene glycol as the main raw material to prepare a stable and uniform cutting slurry, and then the silicon wafer is cut.

[0003] The method of cutting silicon ingots into silicon wafers involves using a high-speed moving steel wire to drive silicon carbide particles attached to it to rub against the silicon ingot to be cut. As the steel wire rubs against the silicon ingot, the cutting slurry, which includes polyethylene glycol and silicon carbide, attached to the wire also moves along with it. The cutting effect is achieved through the mutual friction between the three. The silicon carbide particles play a "rolling-cracking" role between the silicon ingot and the steel wire, and are the core material for cutting. Therefore, during the cutting process, the cutting fluid needs to promptly remove the enormous frictional heat generated, while ensuring that the cutting medium powder is evenly dispersed, and that the cutting fluid has high wetting and lubrication properties and good corrosion inhibition to reduce cutting medium agglomeration, alleviate steel wire corrosion, and prevent wire breakage. Current cutting fluids' wetting and lubrication properties and corrosion inhibition effects are insufficient to meet the requirements for producing high-quality silicon wafers and require further improvement.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a semiconductor silicon wafer cutting fluid, its preparation method and application. The cutting fluid has high wetting and lubrication properties, which helps to reduce the agglomeration of silicon carbide during the cutting of semiconductor silicon wafers.

[0006] This invention is implemented as follows:

[0007] In a first aspect, the present invention provides a semiconductor silicon wafer cutting fluid, comprising the following components by weight:

[0008]

[0009]

[0010] In an optional embodiment, the dispersant is selected from at least one of boronized polyisobutylene succinimide, boronized polyisobutylene succinimide, and boronized polyisobutylene polysuccinimide;

[0011] Preferably, the semiconductor silicon wafer cutting fluid includes 1-5 parts by weight of a dispersant.

[0012] In an optional embodiment, the dispersant is boronized polyisobutylene succinimide.

[0013] In an optional embodiment, the surfactant is a cationic surfactant;

[0014] Preferably, the semiconductor silicon wafer cutting fluid includes 10-20 parts by weight of surfactant.

[0015] In an optional embodiment, the surfactant is selected from at least one of hexadecyl ether hydroxypropyl quaternary ammonium salt, dodecyl-dimethylsulfonium sulfate methyl ester salt, dodecyl-dimethylbenzyl ammonium chloride, and octadecyltrimethyl ammonium chloride; preferably hexadecyl ether hydroxypropyl quaternary ammonium salt.

[0016] In an optional embodiment, the additive is a borate ester with the chemical formula C. n H 2n+1 OB(OH)2, where n is an integer and 2≤n≤12, preferably n=3;

[0017] Preferably, the semiconductor silicon wafer cutting fluid includes 0.5-2 parts by weight of additives.

[0018] In an optional embodiment, the defoamer is selected from at least one of polysiloxane, sodium stearate and polyvinyl alcohol, preferably polysiloxane;

[0019] Preferably, the semiconductor silicon wafer cutting fluid includes 0.5-2 parts by weight of defoamer.

[0020] Secondly, the present invention provides an application of the semiconductor silicon wafer cutting fluid described in any of the foregoing embodiments in semiconductor silicon wafer cutting.

[0021] Thirdly, the present invention provides a method for preparing the semiconductor silicon wafer cutting fluid described in the foregoing embodiments, wherein a mixture comprising polyethylene glycol, dispersant, surfactant, defoamer and additives is mixed with ultrapure water until the mixture is dissolved to obtain the semiconductor silicon wafer cutting fluid.

[0022] The present invention has the following beneficial effects:

[0023] The semiconductor silicon wafer cutting fluid of this invention has no special requirements for the semiconductor silicon wafer cutting process and requires no special treatment procedures. It is simply mixed with silicon carbide, making it convenient to use. Furthermore, the cutting fluid is environmentally friendly, pollution-free, and has minimal evaporation loss. After cutting, the silicon wafer only needs to be rinsed with pure water, posing no harm to the environment or human health. Therefore, the slurry cutting fluid of this invention has excellent application prospects and great potential for large-scale industrial application in the field of semiconductor silicon wafer cutting. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The dynamic change curves of the cutting fluid obtained in Example 1 and Comparative Example 1 are shown.

[0026] Figure 2 The particle size distribution of silicon carbide in the cutting slurry including the cutting fluids in Example 1 and Comparative Example 1 is shown. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0028] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in the definition and description of composition includes both open-ended terms such as "comprising," "including," etc., and closed-ended terms such as "composed of," etc., and similar meanings. Unless otherwise specified, parts referring to the amount of components refer to parts by weight.

[0029] This invention provides a semiconductor silicon wafer cutting fluid, which, by weight, comprises the following components:

[0030]

[0031] In this embodiment of the invention, polyethylene glycol is used as the main raw material, and a dispersant is added to it to inhibit silicon carbide agglomeration; the surfactant helps to improve the hydrophilicity of the silicon carbide surface and further promotes the uniform dispersion of silicon carbide in the cutting fluid; the defoamer can suppress bubbles and help to avoid uneven dispersion of silicon carbide caused by the presence of bubbles.

[0032] It should be noted that the ultrapure water mentioned in this embodiment is deionized water with a resistance ≥18MΩ, and the semiconductor silicon wafer cutting fluid includes 30-50 parts by weight of ultrapure water, preferably 40-50 parts by weight.

[0033] In some embodiments, the dispersant is selected from at least one of boronized polyisobutylene succinimide, boronized polyisobutylene succinimide, and boronized polyisobutylene polysuccinimide, preferably boronized polyisobutylene succinimide.

[0034] In this embodiment, boronized polyisobutylene succinimide and boronized polyisobutylene polysuccinimide can achieve good dispersion effects as dispersants. However, when boronized polyisobutylene succinimide (also known as T154B) is used as a dispersant, its polymer chains can interact with the silicon carbide surface, forming a relatively stable adsorption layer on the silicon carbide surface. The presence of the adsorption layer can hinder the aggregation of silicon carbide particles, thus further facilitating the dispersion of silicon carbide in the cutting fluid. Furthermore, compared to polyisobutylene succinimide, boronized polyisobutylene succinimide exhibits significantly improved antioxidant properties, anti-friction and wear properties, and sludge dispersibility.

[0035] In some embodiments, the semiconductor silicon wafer cutting fluid includes 1-10 parts by weight of a dispersant, preferably 1-5 parts by weight. Although the presence of the dispersant is beneficial to the dispersion of silicon carbide, if the amount of dispersant is too large, the dispersion effect of silicon carbide will be reduced. Therefore, the amount of dispersant should be within a reasonable range of 1-10 parts by weight.

[0036] In some embodiments, the surfactant is a cationic surfactant; the surfactant is selected from at least one of hexadecyl ether hydroxypropyl quaternary ammonium salt, dodecyl-dimethylsulfonium sulfate methyl ester salt, dodecyl-dimethylbenzyl ammonium chloride and octadecyltrimethyl ammonium chloride; preferably hexadecyl ether hydroxypropyl quaternary ammonium salt.

[0037] During the cutting of silicon ingots to prepare semiconductor silicon wafers, the silicon carbide in the system undergoes intense Brownian motion, resulting in continuous collisions between particles and causing the silicon carbide to acquire a positive charge. Therefore, in this embodiment of the invention, a cationic surfactant is selected. The surfactant carries a positive charge, which generates charge repulsion with the positively charged silicon carbide, thereby facilitating better dispersion of the silicon carbide.

[0038] In this embodiment of the invention, the boronized polyisobutylene succinimide dispersant disperses the particles through an adsorption mechanism. At the same time, the charge repulsion between the surfactants such as hexadecyl ether hydroxypropyl quaternary ammonium salt and silicon carbide promotes the uniform distribution of silicon carbide in the cutting fluid. The dispersant and surfactant work together to further improve the dispersibility of silicon carbide.

[0039] In some embodiments, the semiconductor silicon wafer cutting fluid includes 10-30 parts by weight of surfactant, preferably 10-20 parts by weight. Within the scope of this invention, while surfactants help to further improve the dispersibility of silicon carbide in the cutting fluid, excessive surfactants may actually reduce the dispersibility of silicon carbide in the cutting fluid, possibly because excessive surfactants reduce the stability of the cutting fluid.

[0040] In some embodiments, the additive is a borate ester with the chemical formula C n H 2n+1 OB(OH)2, where n is an integer and 2≤n≤12, preferably n=3.

[0041] Boronate esters act as corrosion inhibitors and lubricants, effectively reducing the breakage rate of the cutting wire. In this embodiment of the invention, the borate esters are obtained by reacting saturated monohydric alcohols with boric acid, and are more effective at reducing the breakage rate of the cutting wire compared to other borate esters such as oleic acid diethanolamide borate ester.

[0042] In some embodiments, the semiconductor silicon wafer cutting fluid includes 0.5-5 parts by weight of additives, preferably 0.5-2 parts by weight.

[0043] In some embodiments, the defoamer is selected from at least one of polysiloxane, sodium stearate and polyvinyl alcohol, preferably polysiloxane;

[0044] In some embodiments, the semiconductor silicon wafer cutting fluid includes 0.5-5 parts by weight of defoamer, preferably 0.5-2 parts by weight.

[0045] This invention provides an application of the semiconductor silicon wafer cutting fluid described in the foregoing embodiments in semiconductor silicon wafer cutting.

[0046] This invention provides a method for preparing the semiconductor silicon wafer cutting fluid described in the foregoing embodiments, wherein a mixture comprising polyethylene glycol, dispersant, surfactant, defoamer and additives is mixed with ultrapure water until the mixture is dissolved to obtain the semiconductor silicon wafer cutting fluid.

[0047] In some embodiments, before cutting the silicon ingot, the semiconductor silicon wafer cutting fluid and silicon carbide are mixed to obtain a cutting slurry, wherein the silicon carbide content in the cutting slurry is 40-60%.

[0048] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0049] Examples 1-11

[0050] Embodiments 1-11 of this application provide a method for preparing a semiconductor silicon wafer cutting fluid, specifically including the following steps:

[0051] Step 1: Weigh out polyethylene glycol, dispersant, surfactant, defoamer, additives and ultrapure water separately for later use;

[0052] Step 2: Add polyethylene glycol, dispersant, surfactant, defoamer and additives to a container, and pour in ultrapure water while stirring continuously. Stir until all materials are completely dissolved and the mixture is uniform and transparent to obtain semiconductor silicon wafer cutting fluid.

[0053] The composition of the semiconductor silicon wafer cutting fluid in each embodiment is shown in Table 1.

[0054] Table 1

[0055]

[0056]

[0057] Comparative Examples 1-10

[0058] Comparative Examples 1-10 of this application provide a method for preparing a semiconductor silicon wafer cutting fluid. The only difference between the method and the examples is that the selection and dosage of polyethylene glycol, dispersant, surfactant, defoamer and additives are not exactly the same. The composition of the semiconductor silicon wafer cutting fluid in each comparative example is shown in Table 2.

[0059] Table 2

[0060]

[0061]

[0062] The wire breaking rate and dynamic surface tension of the cutting fluids obtained in the above embodiments and comparative examples were tested, and the test results are shown in Table 3. The surface tension diagrams of the cutting fluids in the embodiments and comparative example 1 are shown in Table 3. Figure 1 As shown, the specific testing method is as follows:

[0063] The wire breakage rate was determined by mixing the cutting fluids obtained in the above examples and comparative examples with silicon carbide to obtain a slurry cutting fluid with a silicon carbide content of 50%. On the same machine, the prepared cutting slurry was used to cut silicon ingots to prepare semiconductor silicon wafers, and the proportion of the number of cuts with wire breakage during the cutting process was counted out of the total number of cuts.

[0064] The dynamic surface tension of cutting fluid was determined using the bubble method. During the measurement, a capillary tube with an inner diameter of 1 mm was inserted into the liquid to a depth of 2 cm. Inert gas was slowly introduced into the tube to apply pressure to the liquid, causing it to form bubbles at the tube end and escape. If inert gas was continued to be introduced, the bubbles would suddenly expand and rapidly detach from the tube end or burst abruptly. By controlling different effective residence times of the bubbles (bubble life time), different surface tension values ​​were obtained, and a complete dynamic change curve of the dynamic surface tension was presented.

[0065] Table 3

[0066]

[0067] As can be seen from the test results in Table 3, compared with Comparative Examples 1-10, the cutting fluid of Examples 1-11 has a lower wire breakage rate and a smaller dynamic surface tension, indicating that the cutting fluid of the examples has better wetting performance and better cutting effect.

[0068] In addition, the particle size distribution of silicon carbide particles in the cutting mortar corresponding to Example 1 and Comparative Example 1 in the wire breakage rate test was tested in this invention, and the results are as follows: Figure 2 As shown, the particle size distribution curve of the cutting fluid with boronized polyisobutylene succinimide dispersant shifts towards smaller particle sizes, indicating better dispersion performance, lower probability of silicon carbide agglomeration, and better dispersibility. Furthermore, the Zeta potential of the cutting fluids in Example 1 and Comparative Example 1 was tested. The Zeta potential of the cutting fluid in Example 1 was -40.2, while that in Comparative Example 1 was -30.7. The larger absolute value of the Zeta potential in Example 1 indicates better dispersibility, further demonstrating that the cutting fluid with boronized polyisobutylene succinimide dispersant is more conducive to the uniform distribution of silicon carbide.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A semiconductor silicon wafer cutting fluid, characterized in that, Based on parts by weight, it includes the following components: The dispersant is selected from at least one of boronized polyisobutylene succinimide and boronized polyisobutylene polysuccinimide; the surfactant is selected from at least one of hexadecyl ether hydroxypropyl quaternary ammonium salt, dodecyl-dimethylsulfonium sulfate methyl ester salt, dodecyl-dimethylbenzyl ammonium chloride, and octadecyltrimethyl ammonium chloride; the additive is a borate ester with the chemical formula C. n H 2n+1 OB(OH)2, where n is an integer and 2≤n≤12.

2. The semiconductor silicon wafer cutting fluid according to claim 1, characterized in that, The semiconductor silicon wafer cutting fluid includes 1-5 parts by weight of dispersant.

3. The semiconductor silicon wafer cutting fluid according to claim 1 or 2, characterized in that, The dispersant is boronized polyisobutylene succinimide.

4. The semiconductor silicon wafer cutting fluid according to claim 1, characterized in that, The semiconductor silicon wafer cutting fluid includes 10-20 parts by weight of surfactant.

5. The semiconductor silicon wafer cutting fluid according to claim 1, characterized in that, The surfactant is selected from hexadecyl ether hydroxypropyl quaternary ammonium salt.

6. The semiconductor silicon wafer cutting fluid according to claim 1, characterized in that, n=3。 7. The semiconductor silicon wafer cutting fluid according to claim 1, characterized in that, The semiconductor silicon wafer cutting fluid includes 0.5-2 parts by weight of additives.

8. The semiconductor silicon wafer cutting fluid according to claim 1, characterized in that, The defoamer is selected from at least one of polysiloxane, sodium stearate and polyvinyl alcohol.

9. The semiconductor silicon wafer cutting fluid according to claim 8, characterized in that, The defoamer is selected from polysiloxane.

10. The semiconductor silicon wafer cutting fluid according to claim 1, characterized in that, The semiconductor silicon wafer cutting fluid includes 0.5-2 parts by weight of defoamer.

11. The application of the semiconductor silicon wafer cutting fluid according to any one of claims 1-10 in semiconductor silicon wafer cutting.

12. A method for preparing a semiconductor silicon wafer cutting fluid according to any one of claims 1-10, characterized in that, The semiconductor silicon wafer cutting fluid is obtained by mixing a mixture of polyethylene glycol, dispersant, surfactant, defoamer and additives with ultrapure water until the mixture is dissolved.

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