Plasma etching resistant coating for high-precision chip etching machine and preparation method of plasma etching resistant coating

Abstract

The invention belongs to the field of material science, and discloses a plasma etching resistant coating for a high-precision chip etching machine and a preparation method. A fluorine element is doped into Y2O3 powder through a liquid phase method, and the coating is prepared on an Al2O3 matrix. When R = n (F-) / n (Y < 3 + >) and R is more than 0 and less than or equal to 50, the density of the coating is greatly improved by adding fluorine. And the solid content of the slurry and the content of the dispersing agent, the binder and the plasticizer are optimized, so that the density of the coating can reach 99% or above. And when the sintering temperature is 1400-1500 DEG C, the coating and the matrix form a high-hardness compact Y3Al5O12 (YAG) phase through an interface reaction. The YAG coating inherits the respective chemical stability and hardness of Y2O3 and Al2O3 materials, the fluorine element reduces the sintering driving force, the coating density is improved, the phase purity is guaranteed, and the good binding force between the coating and a base body is kept.

Description

Technical Field

[0001] The present invention relates to the field of materials science, and particularly to a plasma-resistant etching coating for a high-precision chip etching machine and a preparation method thereof. Background Art

[0002] In the field of semiconductor manufacturing, the precision requirements of chips impose more stringent requirements on processing equipment. In particular, the corrosion resistance of the cavity material to fluorine plasma seriously affects the qualification rate of wafer manufacturing. Therefore, enhancing the corrosion resistance of the cavity material is crucial. Compared with metals and organic materials, ceramic materials generally have better corrosion resistance and higher working temperatures. A variety of ceramic materials have been applied to plasma etching equipment, such as quartz, SiC, Al 2 O 3 、Y 2 O 3 、YAG, YOF, and YF 3 etc. However, quartz and SiC materials are prone to react with halogens to produce particulate contamination and reduce service life. Alumina materials are widely used for the cavity walls, with high hardness and resistance to physical etching, but they will react with halogen gases and form volatile AlF 3 particles in high-energy fluorine-containing plasmas. In contrast, yttrium-based materials such as Y 2 O 3 、YAG, YOF, and YF 3 etc. have low chemical reactivity and strong resistance to fluorocarbon plasma etching, so they are beneficial for corrosion resistance. Compared with Y 2 O 3 , YF 3 has lower reactivity and can better maintain surface cleanliness. High-density YOF coatings also have excellent anti-plasma performance and can reduce contamination. However, Y 2 O 3 、YOF, and YF 3 materials have poor mechanical properties and are prone to lattice damage and crack formation and other defects under high-power plasma bombardment, and the defect sites are often the locations of concentrated corrosion. Based on semiconductor manufacturing experience at home and abroad, it is generally required that the etching machine cavity material meet the following requirements: (1) high purity and low metal impurity content. If the material contains other alkali metals or heavy metals such as Na, K, Fe, Ni, Cu, etc., it is easy to react with plasma during etching to form particles; (2) the main component has stable chemical properties and is compatible with Cl 2 , N 2 , C 2 H 4 , O 2 , BCl 3, F, HBr, HCl and other halogen corrosive gases have a slow reaction rate; (3) the grains are fine and the content of grain boundary phase is small, which reduces the possibility of grain shedding and particle contamination caused by preferential corrosion of intergranular phase; (4) the density is as high as possible, with no voids or extremely low porosity; (5) it has excellent mechanical properties and is easy to produce and process. However, the coatings produced by spraying technology are very sensitive to conditions, which can cause adhesion problems, and the cost of preparing high-purity and dense materials is very high.

[0003] Therefore, it is very important to find an economical and simple method to prepare uniform and high-density corrosion-resistant coatings. 2 O 3 Because the bond energy of YO bond is enhanced and the chemical property of YAG is more stable, YAG ceramics have high corrosion resistance. However, the traditional spraying method of YAG often forms 2 O 3 or monoclinic phase, reducing the purity and hardness of the coating. A pressureless sintering method - Q. Zhu, S. N. Ding, J. Q. Xiahou, S. Y. Li, X. D. Sun, J. - G. Li. A groundbreaking strategy for fabricating YAG:Ce 3+ Transparent ceramic films via sintering of LRH nanosheets on asapphire substrate.Chemical Communications, 56, (84), 12761-12764, 2020, YAG:Ce3+ transparent ceramic films were prepared on sapphire substrates using layered rare earth hydroxides (LRH, R: rare earth ions). This method can achieve uniform distribution and high phase purity of aluminum compared to high-temperature solid-phase methods. In addition, fluorine can enhance crystallization and thermal stability, so it is often used as a sintering aid to increase the density of ceramics. However, fluorine loss may occur during high-temperature calcination, and the uneven distribution of fluorine in the sintering aid often leads to uneven grain growth of ceramic materials. It is difficult to improve the density and hardness of the coating by spraying technology. In contrast, the inherent fluorine content can make the grains grow uniformly and avoid these problems. The interlayer nitrates in LRH can exchange with fluoride ions to form a solid solution containing fluorine. This precursor can then be calcined at low temperature to produce rare earth fluoride oxides, ensuring uniform distribution of fluorine throughout the material and improving the density of the coating. In addition, by optimizing the slurry formula, the sintering performance of the coating prepared by fluorine-containing powder can be significantly improved, densification can be promoted, and the hardness of the coating can be significantly improved. Summary of the invention

[0004] In view of the deficiencies of the existing YAG corrosion-resistant protective coatings, the present invention proposes a plasma-resistant etching coating for high-precision chip etching machines and a preparation method thereof. Therefore, in this study, after synthesizing LRH by low-temperature coprecipitation, fluorine-containing LRH was successfully prepared by the ion exchange method. Subsequently, Y was obtained by calcination 2 O 3-R F 2R . These methods utilize precursors with a hierarchical structure to effectively incorporate fluorine, thereby obtaining highly purified and well-dispersed powders. These powders can be used to manufacture slurries for high-density and high-purity corrosion-resistant coatings. The hardness of the sintered ceramic samples can be comparable to that of the substrate, while maintaining high phase purity and not introducing foreign metal cations. In addition, the two-dimensional structure of the precursor limits the growth of grains, thereby reducing the grain size. In summary, by controlling the interfacial reaction and using the fluorinated oxide Y 2 O 3-R F 2R , a ceramic coating with good adhesion, high chemical stability, high hardness, high density, purity, and small grain size can be obtained, which is expected to achieve long-term corrosion resistance in the etching chamber

[0005] The technical solution of the present invention is as follows: A plasma-resistant etching coating for a high-precision chip etching machine, which is composed of a well-bonded, high-purity, and high-density YAG phase formed by the interfacial reaction between Y 2 O 3-2R F 2R and Al 2 O 3 . The density of the sintered coating is higher than 99%

[0006] The core material in the plasma-resistant etching coating for the high-precision chip etching machine includes a rare-earth layered compound uniformly doped with fluoride ions that can play a role in promoting sintering. The powder material of the rare-earth layered compound is Y 2 O 3-2R F 2R , R = n(F - ) / n(Y 3+ ), 0 < R ≤ 50

[0007] Preferably, 1 ≤ R ≤ 50

[0008] A preparation method of a plasma-resistant etching coating for a high-precision chip etching machine. The powder material for preparing the coating is Y 2 O 3-2R F 2R , and the steps are as follows

[0009] Step 1: Use acetone, ethanol and distilled water to ultrasonically clean the aluminum oxide substrate, immerse the aluminum oxide substrate after cleaning in a mixed solution A and heat it in a water bath; make the surface of the aluminum oxide substrate adsorb a layer of hydroxyl groups, and make the surface hydrophilic. 2 O:NH 4 OH:30%H 2 O 2 The mixed solution A is stored in a mixed solution B; the mixed solution A is composed of H 2 SO 4 : Mass fraction is 30% H 2 O 2 The solution is mixed in a ratio of 3:1; the mixed solution B is composed of H 2 O:NH 4 OH: mass fraction 30% H 2 O 2 The solution is a 5:1:1 mixture;

[0010] Step 2: Weigh ag Y 2 O 3-R F 2R ,; dissolve b wt% dispersant PEI in deionized water, and dissolve it evenly by ultrasound; then add Y 2 O 3-R F 2R The powder was fully dispersed by ultrasonic treatment, and finally c wt% of binder PVA and d wt% of plasticizer PEG were added and ultrasonic treatment was continued to prepare a uniform slurry;

[0011] Step three: adopting the pulling method to make the alumina substrate in step one absorb a layer of the slurry prepared in step two; after the slurry is dried, it is placed in a high-temperature sintering furnace, further heated and kept warm to obtain a coating.

[0012] b=0.01a; c=0.12a; d=0.024a.

[0013] The water bath heating temperature is room temperature to 80° C., and the heating time is 1 h.

[0014] The insulation temperature in step 3 is 1400-1500°C.

[0015] The Y is prepared by liquid phase method 2 O 3-R F 2R Powder, to ensure the uniform doping of fluorine element, the preparation process is as follows:

[0016] Step 1: Mix the powdered Y 2 O 3 Dissolves in hot nitric acid to form Y(NO 3 ) 3Solution with a concentration of 0.2 - 1 mol / L; Dilute 25 wt% ammonia water to 0.2 - 1 mol / L;

[0017] Step 2: Place the Y(NO 3 ) 3 solution in an ice - water bath and cool it to 3 - 5 °C. Drop the dilute ammonia water into the Y(NO 3 ) 3 solution at 3 - 5 °C at a rate of 2 seconds per drop until the pH value reaches 7.50 - 9.00 to obtain a suspension, and keep it warm and aged for 1 - 2 h;

[0018] Step 3: Centrifuge, wash, and dry the suspension obtained in Step 2 at 60 °C for 24 h to obtain powdered Y 2 (OH) 5 NO 3 ·nH 2 O, that is, LRHs;

[0019] Step 4: Grind the powdered LRHs obtained in Step 3 and disperse them in deionized water, stir and ultrasonicate to obtain a suspension; According to the molar ratio R = n(F - ) / n(Y 3+ ),(0 < R ≤ 50), add the prepared ammonium fluoride solution to the LRHs suspension, stir evenly, and keep it warm and aged for 1 h; The product is centrifuged, washed, and dried at 60 °C for 24 h to obtain a fluorine - containing powder;

[0020] Step 5: Grind the fluorine - containing powder obtained in Step 4, calcine and keep it warm for 2 h, and grind it again to obtain Y 2 O 3-2R F 2R powder.

[0021] The temperature of the ice - water bath is 3 - 5 °C.

[0022] In Step 5: The holding temperature is from room temperature to 600 °C.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: The plasma-resistant etching coating powder material forms a solid solution by incorporating uniform fluorine elements, avoiding the segregation phenomenon after sintering of traditional sintering aids and improving the phase purity; the sintering-promoting effect of fluorine elements increases the coating density to over 99%, with good mechanical properties and a micro-Vickers hardness of up to over 1400 Mpa; fluorine element doping refines the grain size of the precursor, and the unique two-dimensional structure of the precursor restricts grain growth, keeping the grain size of the sintered coating at 1-2 μm; the interfacial reaction enables the coating to maintain good bonding with the substrate, and the coating has high adhesion. Currently, there are many disadvantages in traditional plasma spraying methods, such as high cost, low phase purity, impurity segregation, uneven grain size, and lamellar stacking reducing density, mechanical properties, and bonding strength, etc. The ceramic coating prepared by this method maintains an advanced level in terms of phase purity, density, mechanical properties, grain size, and bonding strength, and has the advantages of adjustable thickness, simple process, low cost, and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the principle of the present invention.

[0025] Figure 2 is the XRD pattern of LYH-RF prepared in Example 1 of the present invention.

[0026] Figure 3 is the FT-IR pattern of LYH-RF prepared in Example 1 of the present invention.

[0027] Figure 4 are the SEM (R = 0, 0.5, 1, 2, 50) and TEM (R = 1) photos of LYH-RF prepared in Example 1 of the present invention. Figure a is the SEM photo of the R = 0 sample; Figure b is the SEM photo of the R = 0.5 sample; Figure c is the SEM photo of the R = 1 sample; Figure d is the SEM photo of the R = 2 sample; Figure e is the SEM photo of the R = 50 sample; Figure f is the TEM photo of the R = 1 sample.

[0028] Figure 5 is Y prepared in Example 1 of the present invention 2 O 3-R F 2R 's XRD pattern.

[0029] Figure 6 is the Y prepared in Example 1 of the present invention 2 O 3-R F 2R 's FT-IR pattern.

[0030] Figure 7 is Y prepared in Example 1 of the present invention 2 O3-R F 2R SEM (R = 0, 0.5, 1, 2, 50) and TEM (R = 1) photographs of

[0031] Figure 8 Y prepared in Example 1 of the present invention 2 O 3-R F 2R SEM spectra showing the relationship between the final coating of

[0032] Figure 9 Y prepared in Example 1 of the present invention 2 O 3-R F 2R SEM spectra showing the relationship between the final coating of

[0033] Figure 10 Y prepared in Example 1 of the present invention 2 O 3-R F 2R SEM spectra showing the relationship between the final coating of

[0034] Figure 11 Y prepared in Example 1 of the present invention 2 O 3-R F 2R SEM spectra showing the relationship between the final coating of

[0035] Figure 12 is Y prepared using the experimental parameters of the optimal solid content, plasticizer content, and binder content in Example 1 of the present invention 2 O 3-R F 2R (R = 0, 1, 50) SEM spectra of the final coating. Figure a is the SEM photo of the sample with R = 0; Figure b is the SEM photo of the sample with R = 1; Figure c is the SEM photo of the sample with R = 50.

[0036] Figure 13 is Y 2 O 3-R F 2R (R = 0, 0.5, 1) Cross-sectional morphology diagrams and element distribution diagrams of the coating after sintering. The a1-a3 group of figures is the SEM photo of the sample with R = 0; the b1-b3 group of figures is the SEM photo of the sample with R = 0.5; the c1-c3 group of figures is the SEM photo of the sample with R = 1.

[0037] Figure 14 is Y 2 O 3-R F 2R (R = 1) XRD diagrams of the coating sintered at different temperatures

[0038] Figure 15 is Y 2 O 3-R F 2R (R = 1) SEM diagrams of the surface of the coating sintered at different temperatures. Figure a is the SEM photo of the sample calcined at 600 °C; Figure b is the SEM photo of the sample calcined at 800 °C; Figure c is the SEM photo of the sample calcined at 1200 °C; Figure d is the SEM photo of the sample calcined at 1300 °C; Figure e is the SEM photo of the sample calcined at 1400 °C; Figure f is the SEM photo of the sample calcined at 1500 °C.

[0039] Figure 16 is Y 2 O 3-R F 2R (R = 1) SEM and EDS diagrams of the cross-section of the coating sintered at different temperatures. The a1-a3 group of figures is the SEM photo of the sample calcined at 800 °C; the b1-b3 group of figures is the SEM photo of the sample calcined at 1300 °C; the c1-c3 group of figures is the SEM photo of the sample calcined at 1400 °C; the d1-d3 group of figures is the SEM photo of the sample calcined at 1500 °C.

[0040] Figure 17 are respectively the alumina matrix and Y 2 O 3-R F 2R (R = 0, 0.5, 1) SEM diagrams of the surface of the coating before and after 8 days of corrosion immersion. The a group of figures is Al2 O 3 SEM images of the surface of the substrate before and after 8 days of immersion; Group b is the SEM images of the surface of the sample with R = 0 before and after 8 days of immersion; Group c is the SEM images of the surface of the sample with R = 0.5 before and after 8 days of immersion; Group d is the SEM images of the surface of the sample with R = 1 before and after 8 days of immersion.

[0041] Figure 18 is alumina substrate and Y 2 O 3-R F 2R Corrosion weight loss curves of coatings (R = 0, 0.5, 1) after 8 days of immersion corrosion.

[0042] Figure 19 are respectively Y 2 O 3-R F 2R EDS spectra of coatings (R = 0, 0.5, 1) after 8 days of immersion corrosion. For Group a1 - a4, they are SEM images of the surface of the sample with R = 0 before and after 8 days of immersion; For Group b1 - b4, they are SEM images of the surface of the sample with R = 0.5 before and after 8 days of immersion; For Group c1 - c4, they are SEM images of the surface of the sample with R = 1 before and after 8 days of immersion. Detailed implementation manners

[0043] The following describes the specific embodiments of the present invention in detail in combination with the technical solutions and drawings.

[0044] The core materials of the plasma - resistant etching coating for high - precision chip etching machines include but are not limited to Y 2 O 3-R F 2R (R = 1 - 50), dispersant PEI, plasticizer PEG, and binder PVA.

[0045] Principle of action (taking the core material Y 2 O 3-R F 2R (R = 1) as an example): Y 2 O 3-R F 2R(R = 1), as an etching-resistant coating precursor material, has a two-dimensional flaky structure with a grain size of about 40 nm. It has good sintering activity, and the small grain size endows the coating with extremely high mechanical properties. The Y-O bond in the yttrium-based material gives it excellent chemical stability and corrosion resistance to fluorine-containing solutions. Fluorine elements are uniformly solid-solved into the yttrium oxide powder, showing a better sintering aid effect. The escape of fluorine elements during the sintering process ensures the phase purity of the coating. Meanwhile, during the sintering process, aluminum elements diffuse into the coating, and an interfacial reaction occurs between the coating and the substrate, enabling the coating to maintain good adhesion and inherit the hardness of the substrate. The use of polymer additives such as dispersant PEI, plasticizer PEG, and binder PVA makes the slurry have high fluidity and solid content, thereby reducing the surface tension of the wet coating blank. Due to the cross-linking effect of the binder and plasticizer, the dry blank has high strength and density, preventing the coating from cracking under the action of surface tension or thermal stress during drying and sintering. Moreover, these additives can be fully pyrolyzed without residue during low-temperature calcination. Therefore, the coating maintains extremely high density and has good corrosion resistance, capable of resisting the corrosion of 20% HF solution and even the etching of fluorocarbon plasma.

[0046] All chemical reagents used in the examples of this invention are of analytical purity grade. XRD phase analysis was carried out using an X’Pert Pro X-ray diffractometer of model PW3040 / 60; the functional groups of the powder were measured using a Nicolet iS5 Fourier transform infrared spectrometer by the standard KBr method; analysis of morphology, crystallinity, etc. was carried out using a FEM-3000F transmission electron microscope; morphology observation and EDS analysis were carried out using a JSM-7001F JEOL field emission scanning electron microscope.

[0047] Example 1

[0048] First, the powdery rare earth oxide Y 2 O 3 was dissolved in hot nitric acid to form a nitrate solution, and then 25% ammonia water was diluted to a concentration of 1 mol / L. Then, the 1 mol / L Y(NO 3 ) 3 solution was placed in an ice-water bath at a temperature of 4 - 5°C. 1 mol / L ammonia water (temperature maintained at 3 - 5°C) was gradually dropped into the nitrate solution at a rate of one drop every two seconds until the pH value reached 9, forming a suspension. Then the suspension was kept warm and aged for 1 hour. The precursor powder was obtained by centrifugal separation and then washed and dried at 60°C. The precursor powder was further dispersed to form a suspension, and then (NH 4) F solution (3 - 5 °C). The obtained product was aged at a constant temperature for 1 h. Then, it was centrifuged, washed, and dried at 60 °C for 24 h to obtain LYH-RF powder (where R = 1 - 50), where R represents the molar ratio n(F-) / n(Y3+). Subsequently, the LYH-RF powder was calcined at a temperature of 600 °C for 2 h and ground thoroughly to obtain Y 2 O 3-R F 2R nano powder.

[0049] Mix the Y 2 O 3-R F 2R nano powder with a dispersant, a binder, a plasticizer, and deionized water to make a slurry. The slurry was coated onto an alumina substrate with a purity of 99% using the dip-coating method. The substrate had a diameter of 20 mm and a thickness of 2 mm.

[0050] First, ultrasonically clean the alumina substrate with acetone, ethanol, and distilled water. Then immerse it in an H 2 SO 4 and 30% H 2 O 2 (in a ratio of 3:1) solution for 1 h to make the substrate surface hydrophilic. Subsequently, store the substrate in a mixture of H 2 O, NH 4 OH, and 30% H 2 O 2 (in a ratio of 5:1:1). To prepare the slurry, dissolve 0.03 g of polyethyleneimine (PEI) dispersant in 8 ml of deionized water and sonicate for 3 minutes to obtain a homogeneous solution. Then, add 3 g of Y 2 O 3-R F 2R powder and sonicate for 10 min to ensure complete dispersion. Finally, add 4 mL of 9 wt% polyvinyl alcohol (PVA) binder and 0.072 g of polyethylene glycol (PEG) plasticizer, and sonicate for 10 minutes again to form a homogeneous slurry. Carefully pick up the Al 2 O 3The substrate is placed in the slurry and then slowly withdrawn from the slurry at a controllable speed. After the coating is naturally dried, it is put into a high-temperature sintering furnace and calcined at 1500 °C for 2 h. For coatings with different fluorine contents, fluorine elements are easily oxidized and completely lost near 800 °C, only promoting the densification of the coating. During the high-temperature sintering process at 1400 - 1500 °C, an interface reaction forms a YAG ceramic coating, which maintains a firm bond with the alumina substrate. In addition, the fluorine content has a significant impact on the coating density. When R < 1, some of the powder is often not doped with fluorine, and after being made into a coating, it often leads to uneven shrinkage, local cracking, and warping; when R = 1, the single-phase YOF powder has good thermal stability and high phase purity, which can effectively and uniformly promote sintering, and the coating maintains good density; when 1 < R ≤ 2, the powder forms Y 5 O 4 F 7 or YF 3 , when R increases from 2 to 50, the powder always remains in the orthorhombic YF 3 phase, and Y 5 O 4 F 7 and YF 3 undergo a phase transformation at high temperature to form Y 2 O 3 , the coating releases more fluorine elements at high temperature, but does not affect the sintering process and has no obvious effect on the density of the coating; when R > 50, the fluorine content is too high, and more voids are formed after the coating is sintered. Macroscopically, the surface of the coating is discontinuous and the density is poor.

[0051] Such as Figure 1 is a schematic diagram of the principle of the present invention; Figure 2 is the XRD pattern of LYH-RF, and LYH-RF all maintain good crystallinity and lamellar structure; Figure 3 is the FT-IR spectrum of LYH-RF, and the vibration absorption peak of NO 3 - gradually disappears when R > 1, proving that F - realizes intercalation; Figure 4 is the SEM (R = 0, 0.5, 1, 2, 50) and TEM (R = 1) photos of LYH-RF, which is consistent with the analysis of its XRD pattern; Figure 5 is the XRD pattern of Y 2 O 3-R F 2R ; Figure 6 is the FT-IR spectrum of Y 2 O 3-R F 2R ; Figure 7 is the XRD pattern of Y 2 O 3-R F 2RSEM (R = 0, 0.5, 1, 2, 50) and TEM (R = 1) photographs; Figure 8 is Y 2 O 3-R F 2R SEM spectrum of the relationship between the final coating (R = 0) and the experimental parameters of the solid content; Figure 9 is Y 2 O 3-R F 2R SEM spectrum of the relationship between the final coating (R = 0) and the experimental parameters of the plasticizer content; Figure 10 is Y 2 O 3-R F 2R SEM spectrum of the relationship between the final coating (R = 0) and the experimental parameters of the binder content; Figure 11 is Y 2 O 3-R F 2R SEM spectrum of the relationship between the final coating (R = 1) and the experimental parameters of the binder content; Figure 12 is YOF prepared with the optimal experimental parameters of solid content, plasticizer content and binder content in Example 1 of the present invention 2 O 3-R F 2R SEM spectra of the final coatings (R = 0, 1, 50); Figure 13 is Y 2 O 3-R F 2R Cross-sectional morphology and element distribution maps of the coatings (R = 0, 0.5, 1) after sintering; Figure 14 is Y 2 O 3-R F 2R XRD patterns of the coating (R = 1) after sintering at different temperatures; Figure 15 is Y 2 O 3-R F 2R SEM images of the surface of the coating (R = 1) after sintering at different temperatures; Figure 16 is Y 2 O 3-R F 2R SEM images of the cross-section of the coating (R = 1) after sintering at different temperatures; Figure 17 are the alumina substrate and Y 2 O 3-R F 2R SEM images of the surface of the coatings (R = 0, 0.5, 1) before and after 8 days of corrosion immersion (a: Al 2 O 3 ; b: R = 0; c: R = 0.5; d: R = 1); Figure 18 are the alumina substrate and Y 2 O 3-R F2R (R = 0, 0.5, 1) Coating corrosion immersion weight loss curves after eight days; Figure 19 Respectively Y 2 O 3-R F 2R (R = 0, 0.5, 1) Coating corrosion immersion EDS spectra after eight days.

[0052] Example 2

[0053] A 20% HF solution was used to simulate the corrosion environment at room temperature, and the corrosion resistance of the samples was evaluated based on mass loss. The samples were immersed in a polytetrafluoroethylene hydrothermal reaction kettle containing 20% HF solution and placed in an oven at 60 °C for 48 h. After immersion, the samples were rinsed in a supersaturated Ca(OH) 2 suspension for about 10 min, and then ultrasonically cleaned in deionized water for 30 min. After drying, the samples were weighed to determine the mass loss. The calculation formula for the corrosion rate is as follows (1):

[0054]

[0055] Where k is the constant of the unit used, ΔW = W 1 -W 2 (W 1 is the initial sample weight, W 2 is the instantaneous or final sample weight), A is the material density, F is the sample surface area, and t is the corrosion time. V is the rate at which the material thins or the rate at which the exposed surface of the material is uniformly corroded away.

[0056] Figure 17 For the alumina matrix and Y 2 O 3-R F 2R (R = 0, 0.5, 1) Surface SEM images of the coating after eight days of corrosion immersion, and the alumina corrosion is classical grain boundary corrosion; Figure 18 For the alumina matrix and Y 2 O 3-R F 2R (R = 0, 0.5, 1) Coating corrosion immersion weight loss curves after eight days, indicating that the dense ceramic coating formed by doping with fluorine has good corrosion resistance; Figure 19 For Y 2 O 3-R F 2R (R = 0, 0.5, 1) Coating corrosion immersion EDS spectra after eight days, indicating that the good corrosion resistance of the dense ceramic coating is attributed to the formation of a surface fluoride passivation layer.

Claims

1. A plasma etching resistant coating for a high-precision chip etcher, characterized in that: The plasma etching resistant coating for high-precision chip etcher is composed of Y2O 3-2R F 2R It reacts with the Al2O3 interface to form a high-purity and high-density YAG phase with good bonding strength, and the density of the sintered coating is higher than 99%.

2. The plasma etching resistant coating for high-precision chip etcher according to claim 1, characterized in that: The core material of the plasma etching resistant coating for high-precision chip etcher includes a rare earth layered compound uniformly doped with fluorine ions that can assist in sintering; the powder material of the rare earth layered compound is Y2O 3-2R F 2R , R = n(F - ) / n(Y 3+ ), 0<R≤50.

3. The plasma etching resistant coating for high-precision chip etcher according to claim 2, characterized in that: 1≤R≤50。 4. A method for preparing a plasma etching resistant coating for a high-precision chip etcher according to any one of claims 1 to 3, characterized in that: The powder material for preparing the coating is Y2O 3-2R F 2R , including the following steps: Step 1: ultrasonically clean the aluminum oxide substrate with acetone, ethanol and distilled water, immerse the cleaned aluminum oxide substrate in a mixed solution A and heat it in a water bath; make a layer of hydroxyl groups adsorbed on the surface of the aluminum oxide substrate to make the surface hydrophilic, and immerse it in a mixed solution B of H2O: NH4OH: 30% H2O2 for storage; the mixed solution A is formed by mixing H2SO4 and 30% H2O2 solution in a ratio of 3:1; the mixed solution B is formed by mixing H2O: NH4OH: 30% H2O2 solution in a ratio of 5:1:1; Step 2: Weighing ag Y2O 3-R F 2R ; Dissolve b wt% of dispersant PEI in deionized water and dissolve it evenly by ultrasound; then add Y2O 3-R F 2R The powder was fully dispersed by ultrasonic treatment, and finally c wt% of binder PVA and d wt% of plasticizer PEG were added and ultrasonic treatment was continued to prepare a uniform slurry; Step three: adopting the pulling method to make the alumina substrate in step one absorb a layer of the slurry prepared in step two; after the slurry is dried, it is placed in a high-temperature sintering furnace, further heated and kept warm to obtain a coating.

5. The method for preparing a plasma etching resistant coating for a high-precision chip etcher according to claim 4, characterized in that: b=0.01a; c=0.12a; d=0.024a.

6. The method for preparing a plasma etching resistant coating for a high-precision chip etcher according to claim 4, characterized in that: The water bath heating temperature is room temperature to 80° C., and the heating time is 1 h.

7. The method for preparing a plasma etching resistant coating for a high-precision chip etcher according to claim 5, characterized in that: The insulation temperature in step 3 is 1400-1500°C.

8. The method for preparing a plasma etching resistant coating for a high-precision chip etcher according to any one of claims 4 to 7, characterized in that: Preparation of Y2O by liquid phase method 3-R F 2R Powder, to ensure uniform doping of fluorine element, the preparation process is as follows: Step 1: Dissolve powdered Y2O3 in hot nitric acid to form a Y(NO3)3 solution with a concentration of 0.2-1 mol / L; dilute 25 wt% ammonia water to 0.2-1 mol / L; Step 2: Cool the Y(NO3)3 solution to 3-5°C in an ice water bath, drip dilute ammonia water into the Y(NO3)3 solution at 3-5°C at a rate of 2 seconds per drop until the pH value reaches 7.50-9.00 to obtain a suspension, and keep it warm for 1-2 hours; Step 3: The suspension obtained in step 2 is centrifuged, washed, and dried at 60°C for 24 h to obtain powdered Y2(OH)5NO3·nH2O, i.e., LRHs; Step 4: Grind the powdered LRHs obtained in step 3 and disperse them in deionized water, stir and ultrasonicate to obtain a suspension; - ) / n(Y 3+ ), 0<R≤50, add the prepared ammonium fluoride solution to the LRHs suspension, stir evenly, and keep warm for 1 hour; the product is centrifuged, washed, and dried at 60°C for 24 hours to obtain a fluorine-containing powder; Step 5: Grind the fluorine-containing powder obtained in step 4, calcine and keep warm for 2 hours, and grind again to obtain Y2O 3-2R F 2R Powder.

9. The method for preparing a plasma etching resistant coating for a high-precision chip etcher according to claim 8, characterized in that: The temperature of the ice water bath is 3-5°C.

10. The method for preparing a plasma etching resistant coating for a high-precision chip etcher according to claim 8, characterized in that: The step 5: the insulation temperature is room temperature to 600°C.

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