Polishing solution for chemically mechanical polishing of silicon carbide liner tube as well as preparation method and application of polishing solution

Abstract

The invention discloses a polishing solution for chemically mechanical polishing of a silicon carbide liner tube and a preparation method and application of the polishing solution. The polishing solution comprises the following raw material components in percentage by mass: 0.1-3% of silicon oxide; 1-5% of cerium oxide; 0.5-5% of an oxidizing agent; 0.2-2% of a surface modifier; 0.0001 to 0.01% of a surfactant; 0.2-2% of a pH buffer agent; and the balance of water. The silicon oxide particles and the surface modifier are added into the cerium oxide polishing solution of the alkaline system, the pH value in the polishing process is controlled through the pH buffering agent, irreversible agglomeration of grinding materials is avoided, and therefore it is guaranteed that the polishing solution has the good polishing effect while having the good polishing rate, the whole polishing solution system is stable, and the polishing effect is good. And aggregation and sedimentation are not easy.

Description

Technical Field

[0001] The invention relates to the technical field of silicon carbide polishing liquid, and in particular to a polishing liquid for chemical mechanical polishing of a silicon carbide liner tube, and a preparation method and application thereof. Background Art

[0002] Since silicon carbide crystals have the characteristics of high Mohs hardness and strong chemical inertness, the post-processing of crystal materials including cutting, grinding and CMP polishing has the problems of long processing time and relatively low process efficiency. At present, the chemical mechanical polishing liquid systems widely used in the silicon carbide CMP polishing process mainly include silicon oxide-hydrogen peroxide CMP polishing liquid and α-Al2O3-potassium permanganate CMP polishing liquid, which uses Mohs hardness second only to silicon carbide. The former, the polishing speed of the silica sol system is very low, mainly because: the hardness of silicon oxide is small (6-7) and the chemical action of the oxidant is weak. The latter, the aluminum oxide system has the problem of difficult control of the surface polishing effect, mainly because the particle hardness is high, and the stability of the particles may deteriorate during the circulation of the polishing liquid to form agglomerates and then cause surface scratches, thereby affecting the polishing quality.

[0003] Therefore, improving the removal rate of the polishing liquid and ensuring its polishing quality during use are technical difficulties that need to be solved for silicon carbide CMP polishing liquid. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a polishing liquid for chemical mechanical polishing of a silicon carbide liner, and a preparation method and use thereof, so as to solve the problems in the prior art.

[0005] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0006] The present invention provides a polishing liquid for chemical mechanical polishing of a silicon carbide liner, comprising the following raw material components in percentage by weight:

[0007]

[0008] For example, the amount of silicon oxide used can be 0.1-0.5%, 0.5-1%, 1-1.5%, 1.5-2%, 2-2.5%, or 2.5-3%.

[0009] For example, the mass ratio of cerium oxide can be 1-2%, 2-3%, 3-4%, or 4-5%.

[0010] For example, the dosage of the oxidant can be 0.5-1%, 1-2%, 2-3%, 3-4%, 4-5%, preferably 2-4%.

[0011] For example, the dosage of the surface modifier can be 0.2-0.5%, 0.5-1%, 1-1.5%, or 1.5-2%.

[0012] For example, the dosage of the surfactant can be 0.0001-0.001%, 0.001-0.005%, or 0.005-0.01%.

[0013] For example, the dosage of the pH buffer can be 0.2-0.3%, 0.3-0.4%, 0.4-0.5%, 0.5-0.6%, 0.6-1.0%, 1-1.5%, or 1.5-2%.

[0014] Preferably, the particle size of the silicon oxide is 0.05-0.5 μm, more preferably 0.05-0.2 μm.

[0015] Preferably, the silicon oxide particles have a morphology of one or more of spherical, quasi-spherical, and peanut-shaped.

[0016] Preferably, the silicon oxide is colloidal silicon dioxide.

[0017] Preferably, the particle size of the cerium oxide is 0.05-1 μm, more preferably 0.05-0.3 μm.

[0018] Preferably, the particle morphology of the cerium oxide is one or more selected from spherical, quasi-spherical, flaky, and amorphous.

[0019] Preferably, the specific surface area of ​​the cerium oxide is 35 to 55 m 2 / g.

[0020] Preferably, the oxidant is potassium permanganate.

[0021] Preferably, the surface modifier is one or more selected from sodium polyacrylate, polypropylene alcohol, sodium hydroxymethyl cellulose and polyacrylamide-2-methylpropane sulfonic acid.

[0022] Preferably, the surfactant is one or more selected from glycerol, polyglycerol, sodium lauryl sulfate, sodium oleate, polymethacrylic acid, polyvinyl pyrrolidone, triethanolamine oleate soap, polysorbate-20, fatty alcohol polyoxyethylene ether, sodium fatty acid methyl ester sulfonate, sodium perfluorononenyloxybenzene sulfonate and nonylphenol polyoxyethylene ether.

[0023] Preferably, the pH buffer is one or more selected from sodium carbonate-sodium bicarbonate, potassium carbonate-potassium bicarbonate, acetic acid-sodium acetate, disodium hydrogen phosphate-sodium dihydrogen phosphate and potassium hydroxide-potassium carbonate.

[0024] Preferably, the pH of the pH buffer is 9-11.

[0025] Preferably, the raw material components further include a pH adjuster, and the pH adjuster is a strong base.

[0026] More preferably, the pH adjuster is one or more selected from sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide.

[0027] Preferably, the pH of the polishing liquid is 7-9.

[0028] The present invention also discloses a method for preparing the polishing liquid as described above, comprising the following steps:

[0029] The cerium oxide, the surface modifier and water are mixed to form a concentrated solution;

[0030] After mixing the surfactant, the oxidant, the pH buffer and water, a pH adjuster is added to adjust the pH to 7 to 9 to obtain a mixed solution;

[0031] The concentrated solution, the mixed solution and the silicon oxide are mixed to obtain a polishing solution.

[0032] Preferably, in the concentrated solution, the content of cerium oxide is 10-20 wt%.

[0033] The invention also discloses the use of the polishing liquid as described above as a polishing liquid in chemical mechanical polishing of silicon carbide liner.

[0034] The invention discloses a polishing liquid for chemical mechanical polishing of a silicon carbide liner, a preparation method and uses thereof. Silicon oxide particles and a surface modifier are added to a cerium oxide polishing liquid in an alkaline system, and a pH buffer is used to control the pH value during the polishing process to avoid irreversible agglomeration of abrasives, thereby ensuring that the polishing liquid has a good polishing rate and a good polishing effect during the polishing process, and the entire polishing liquid system is stable and not easy to aggregate or settle. DETAILED DESCRIPTION

[0035] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0036] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods in the following examples without specifying specific conditions are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

[0037] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0038] The raw materials used in the following examples and comparative examples of the present invention are as follows:

[0039] Cerium oxide: spherical, particle size is 100-200nm, specific surface area is 40m 2 / g.

[0040] Colloidal silica: spherical, particle size is 60-180nm.

[0041] The particle size was tested using a Biotek 2600 particle size analyzer, and the specific surface area was tested using a specific surface area and pore size analyzer.

[0042] Examples 1 to 7

[0043] Examples 1 to 7 provide a specific polishing liquid, and the preparation method is as follows:

[0044] (1) mixing cerium oxide, a surface modifier and water to form a concentrated solution; the content of cerium oxide in the concentrated solution is 20 wt %;

[0045] (2) mixing a surfactant, potassium permanganate, a pH buffer and water, and adding a sodium hydroxide solution to adjust the pH to 9 to obtain a mixed solution;

[0046] (3) The concentrated solution, the mixed solution and silicon oxide are mixed to obtain a polishing solution.

[0047] In the polishing liquid, the amounts of silicon oxide, cerium oxide, surface modifier, surfactant, potassium permanganate and pH buffer are shown in Table 1, and the balance is water.

[0048] Comparative Examples 1 to 7

[0049] Comparative Examples 1 to 7 are comparative examples of the embodiments, and their preparation methods are basically the same as those of the embodiments, except that the raw material components and amounts are different, as shown in Table 1.

[0050] Table 1 0.1-0.3

[0051]

[0052]

[0053] The polishing liquids prepared in Examples 1 to 7 and Comparative Examples 1 to 7 were subjected to the following performance tests: polishing rate, number of scratches, surface roughness, pH value of the polishing liquid after polishing for 8 hours, softness of the bottom sedimentation layer after 15 days of placement, and particle size test. The test results are shown in Tables 2 to 3, respectively.

[0054] The test method is as follows:

[0055] 1. Polishing rate: A single-sided polishing machine of Zhejiang Mingzheng 36B size was used to polish a 6-inch silicon carbide substrate, and the quality difference of the silicon carbide substrate before and after polishing was recorded, and then the polishing rate was calculated; polishing machine table: 915mm, polishing liquid prepared by the embodiment, polishing liquid flow rate 400ml / min, polishing pressure: 238g / cm 3 , lower plate speed 40rpm.

[0056] The polishing time is 1h.

[0057] Polishing rate = removal thickness (um) / polishing time (h) = removal mass (mg) / 56.52 (g / cm2) / polishing time (h).

[0058] 2. Number of scratches: The silicon carbide substrate for polishing rate test was inspected for scratches and observed with the naked eye under a strong light (Yamada Optics YP250). Bright lines longer than 2 cm were identified as scratches, and the number of scratches was recorded.

[0059] 3. Surface roughness: Use VEECO atomic force microscope for testing. The test area of ​​each position is 5μm*5μm, and the roughness of 3 positions is calculated as the average value.

[0060] 3. The softness of the bottom sediment layer after 15 days of storage: observe the sedimentation state of the particles in the transparent container with the naked eye after shaking; if it immediately becomes a uniform turbid suspension after shaking and will not stratify within 2 hours, the dispersion is easy to disperse; if it is difficult to become a uniform suspension again after shaking, and it will quickly stratify within 30 minutes, the dispersion is at the gel level; if it cannot be shaken, or stratifies immediately after shaking, the dispersion is at the compacted level.

[0061] 4. Particle size: After the polishing liquid was left to stand for 1 week, 2 weeks, 3 weeks, and 4 weeks, the particle size of the polishing liquid was tested using a Bette 2600 particle size analyzer.

[0062] Table 2

[0063]

[0064] Table 3 Stability evaluation of particles

[0065]

[0066]

[0067] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A polishing liquid for chemical mechanical polishing of a silicon carbide liner, characterized in that: The raw material components include the following weight percentage:

2. The polishing liquid according to claim 1, characterized in that Includes one or more of the following features: The particle size of the silicon oxide is 0.05 to 0.5 μm; The silicon oxide particles have a morphology of one or more of spherical, quasi-spherical, and peanut-shaped; The silicon oxide is colloidal silicon dioxide; The particle size of the cerium oxide particles is 0.05 to 1 μm; The particle morphology of the cerium oxide is one or more selected from spherical, quasi-spherical, flaky, and amorphous; The specific surface area of ​​the cerium oxide is 35 to 55 m 2 / g.

3. The polishing liquid according to claim 1, characterized in that The oxidant is potassium permanganate; And / or, the surface modifier is one or more selected from sodium polyacrylate, polypropylene alcohol, sodium hydroxymethyl cellulose and polyacrylamide-2-methylpropane sulfonic acid.

4. The polishing liquid according to claim 1, characterized in that The surfactant is one or more selected from glycerol, polyglycerol, sodium lauryl sulfate, sodium oleate, polymethacrylic acid, polyvinyl pyrrolidone, triethanolamine oleic acid soap, polysorbate-20, fatty alcohol polyoxyethylene ether, sodium fatty acid methyl ester sulfonate, sodium perfluorononenyloxybenzene sulfonate and nonylphenol polyoxyethylene ether.

5. The polishing liquid according to claim 1, characterized in that The pH buffer is one or more selected from sodium carbonate-sodium bicarbonate, potassium carbonate-potassium bicarbonate, acetic acid-sodium acetate, disodium hydrogen phosphate-sodium dihydrogen phosphate and potassium hydroxide-potassium carbonate; and / or, the pH of the pH buffer is 9 to 11; And / or, the raw material components further include a pH adjuster, and the pH adjuster is a strong base.

6. The polishing liquid according to claim 5, characterized in that The pH regulator is one or more selected from sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide.

7. The polishing liquid according to claim 1, characterized in that The pH value of the polishing liquid is 7-9.

8. A method for preparing a polishing liquid according to any one of claims 1 to 7, characterized in that: The steps include: The cerium oxide, the surface modifier and water are mixed to form a concentrated solution; After mixing the surfactant, the oxidant, the pH buffer and water, a pH adjuster is added to adjust the pH to 7 to 9 to obtain a mixed solution; The concentrated solution, the mixed solution and the silicon oxide are mixed to obtain a polishing solution.

9. The preparation method according to claim 8, characterized in that: In the concentrated solution, the content of cerium oxide is 10-20wt%.

10. Use of the polishing liquid as claimed in any one of claims 1 to 7 as a polishing liquid in chemical mechanical polishing of silicon carbide liner.

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