Preparation method of yttrium oxide coating for inhibiting fluorescence defects

Abstract

The invention provides a preparation method of an yttrium oxide coating for inhibiting fluorescence defects, which comprises the following steps: providing powder with the purity of more than 99.99% and the particle size of 80% of the powder between 15 microns and 45 microns; calcining the powder at the calcining temperature of more than or equal to 800 DEG C for the calcining time of more than or equal to 2 hours; taking the calcined powder as a raw material, and forming an yttrium oxide coating by adopting a plasma spraying process; wherein in the plasma spraying process, the spraying distance ranges from 150 mm to 200 mm, and the powder feeding speed ranges from 20 g / min to 30 g / min. The coating prepared by adopting the preparation method provided by the invention can reduce the occurrence of abnormal conditions that the judgment of the etching end point is influenced by the fluorescent defect of the coating of the etching equipment.

Description

Technical Field

[0001] This application relates to the field of semiconductor devices, and more specifically, to a method for repairing defects in anti-plasma corrosion coatings. Background Technology

[0002] In semiconductor manufacturing, ceramic coatings such as yttrium oxide are widely used in key components of etching equipment, such as the inner wall of the reaction chamber and the spray plate, due to their excellent high temperature resistance and resistance to plasma corrosion.

[0003] Currently, these coatings are basically prepared based on plasma spraying technology. However, due to the characteristics of materials and processing technology, the coatings prepared by plasma spraying technology inevitably have porosity defects.

[0004] Impurities inside the material being plasma-sprayed can cause lattice distortion in the resulting coating.

[0005] During plasma spraying, the different melting and solidification states of coating particles can lead to abnormalities such as unmelted particles and oxygen vacancies in the coating.

[0006] When the etching chamber is working, these defects and anomalies can cause fluorescence with different spectra and intensities to be generated, affecting the determination of the etching endpoint and the stability of equipment operation. Summary of the Invention

[0007] This application provides a method for preparing a yttrium oxide coating that suppresses fluorescence defects, thereby solving a series of problems caused by poor stability of the etching process due to fluorescence defects in the coating.

[0008] According to one aspect of the embodiments of this application, a method for preparing a yttrium oxide coating to suppress fluorescence defects is provided, comprising:

[0009] Provides purity greater than 99.99%. The powder has a particle size of 15μm-45μm.

[0010] Calcination Powder, calcined at a temperature greater than or equal to 800℃, and calcined for a time greater than or equal to 2 hours;

[0011] Calcinated Yttrium oxide coating is formed using powder as raw material and plasma spraying process.

[0012] During plasma spraying, the spraying distance is between 150-200mm and the powder feeding rate is between 20-30g / min.

[0013] Optionally, the provided Powder, with a particle size between 15μm and 45μm.

[0014] Optionally, during plasma spraying, the argon flow rate is between 50-60 NLPM and the hydrogen flow rate is between 5-15 NLPM.

[0015] Optionally, the substrate may be preheated to 200°C before plasma spraying.

[0016] Optionally, the thickness of the yttrium oxide coating is between 5 μm and 80 μm.

[0017] Optionally, after plasma spraying, the coating may be annealed; wherein the annealing temperature is between 900-1200℃, and the heating and cooling rates are ≤5℃ / min.

[0018] The yttrium oxide coating preparation method for suppressing fluorescence defects provided in this application uses yttrium oxide powder with a particle size between 15μm and 45μm, which can avoid the formation of impurities or rare earth element segregation in the coating due to excessively large or small powder particle size. During plasma spraying, the spraying distance is between 150-200mm and the powder feeding rate is between 20-30g / min. The powder spraying distance, powder feeding rate, and powder particle size are matched to avoid over-oxidation and reduce fluorescence defects. In other words, the yttrium oxide coating prepared by the yttrium oxide coating preparation method for suppressing fluorescence defects provided in this application can reduce the occurrence of abnormal situations in etching equipment where the determination of the etching endpoint is affected by the fluorescence defects of the coating. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0020] Figure 1 This is a metallographic image of the coating obtained using Example 1 in this application. Detailed Implementation

[0021] The embodiments of this application will be described in detail below with reference to the accompanying drawings and examples.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0023] This embodiment provides a method for preparing a yttrium oxide coating to suppress fluorescence defects, including:

[0024] S1) Provides purity greater than 99.99%. The powder has a particle size between 15μm and 45μm.

[0025] In this step, The purity of the powder affects the corrosion resistance of the coating. In some implementations, not only is powder purity required, but also... Metallic impurities in the powder are further screened, for example, by inductively coupled plasma mass spectrometry (ICP-MS) or gas-distillation mass spectrometry (GDMS). The content of these elements should be controlled to be less than 0.01%. These elemental impurities not only form oxygen vacancies and lattice defects, but also, when excited in the etching equipment, generate high-intensity fluorescence at their aggregation sites. Furthermore, the peak range of these fluorescences overlaps with the detection wavelength of the etching endpoint, easily leading to misjudgment of the etching endpoint. By controlling... The content of these elemental impurities can effectively prevent process abnormalities in etching equipment.

[0026] In this step, when the provided When the powder particle size is <15μm, especially including particles <5μm, it is prone to agglomeration due to its large specific surface area and high surface energy, forming loose "secondary particles." These particles readily adsorb organic and metallic particles (such as Fe and Cr) from the air, forming agglomerates with relatively high impurity content. This leads to uneven coating thickness and the formation of localized fluorescence emission centers. When the powder particle size is >45μm, impurity segregation (rare earth element aggregation) occurs. If melting is insufficient, these rare earth element agglomerates will remain in the coating, introducing luminescent centers (e.g., ...). (A transition occurs within the cell, producing red fluorescence). The powder particle size is controlled between 15μm and 45μm, and the process parameters can be stably controlled. It will not agglomerate due to being too small, nor will it settle due to being too large. At the same time, it avoids the agglomeration of impurities when it is <5μm and the segregation of impurities when it is >45μm. Even if impurities are present, they will not form fluorescence peaks with high light intensity and concentrated fluorescence band, thus reducing the probability of the etching equipment misjudging the etching endpoint.

[0027] S2) Calcination of this Powder, calcined at a temperature greater than or equal to 800℃, and calcined for a duration greater than or equal to 2 hours.

[0028] In this step, before the spraying operation, the coating is pre-treated. Calcination of the powder effectively removes adsorbed water and organic pollutants, preventing organic impurities from being introduced into the luminescent centers. In some embodiments, the powder is calcined and cooled to a certain temperature. The powder must be used within 10 minutes, otherwise it needs to be pre-calcined again.

[0029] In some embodiments, the substrate material to be sprayed also needs to be preheated at a temperature between 200-220°C. Preheating the substrate material can effectively reduce the cooling rate of the molten particles, resulting in a coating with excellent crystallization quality and reduced porosity.

[0030] S3) after calcination Using powder as raw material, a yttrium oxide coating is formed by plasma spraying. During the plasma spraying process, the argon flow rate is between 50-60 NLPM, the spraying distance is between 150-200 mm, and the powder feeding rate is between 20-30 g / min.

[0031] In this step, the parameters of the plasma spraying process are controlled to ensure... The powder can be fully melted without excessive oxidation, reducing coating defects and correspondingly reducing fluorescence defects, thus preventing the formation of fluorescence emission centers. Using a spraying distance of 150-200mm and a powder feed rate of 20-30g / min ensures uniform melting of the powder in the flame, reducing defects caused by excessive melting of unmelted particles and lowering the fluorescence intensity caused by abnormal impurities.

[0032] In some embodiments, after plasma spraying, the coating is further annealed; wherein the annealing temperature is between 900-1200°C, and the heating and cooling rates are ≤5°C / min, in order to reduce lattice defects.

[0033] Example 1

[0034] 1. Raw material preparation:

[0035] Select 99.995% purity Powder with a particle size between 1545 μm;

[0036] Will The powder was calcined at 800℃ for 2 hours, cooled, and then passed through a 200-mesh sieve.

[0037] 2. Thermal plasma spraying:

[0038] - Main argon flow rate 50 NLPM, auxiliary hydrogen flow rate 10 NLPM, spraying distance 150 mm, powder feeding rate 25 g / min;

[0039] - Spray gun power 30 kW, substrate preheated to 200℃, coating thickness 50-80μm.

[0040] 3. Post-processing:

[0041] - Annealing treatment: Hold at 1000℃ for 2 hours, with a heating / cooling rate of 5℃ / min.

[0042] 4. Testing:

[0043] The coating is pure white and shows no visible fluorescence when exposed to ultraviolet light;

[0044] PL spectroscopy (photoluminescence spectroscopy detection) showed a fluorescence peak of less than 30 a.u.;

[0045] The coating porosity is 1.5%, and the metallographic image is as follows. Figure 1 As shown, the microstructure is smooth and the molten particles have excellent spreadability.

[0046] The parameters shown in Example 1 are for particle sizes between 15-45 μm. Optimal powder coating parameters.

[0047] The table below shows the parameters provided in Example 1, under the condition of a single control parameter variable. Comparative data on powder coating operations.

[0048]

[0049] Based on the comparative data in the table above, for 15-45μm There is a correlation between the porosity of powders and coatings and the fluorescence peak intensity; the higher the porosity, the higher the fluorescence peak intensity. However, when... As the powder particle size distribution changes, the more powder particles <15μm, the stronger the fluorescence peak intensity (over 180.au) will be due to impurity agglomeration, even with a low porosity (3%±0.5%). The more powder particles >45μm, the stronger the fluorescence peak intensity (over 300.au) will be due to rare earth element impurity segregation, even with a low porosity (3.5%±0.5%).

[0050] Based on the analysis of comparative examples B1 and B2 in the table above, the gas flow rate affects the arc stability. When the hydrogen flow rate is less than or equal to 5 L / min, the flame temperature is insufficient, resulting in the formation of unmelted particles. These unmelted particles increase the porosity and lead to an increase in the fluorescence peak intensity. When the hydrogen flow rate is greater than or equal to 15 L / min, the flame oxidizing power is enhanced, the oxygen content of the coating is abnormal, and the oxygen vacancies cause an increase in the fluorescence peak intensity.

[0051] Based on the analysis of comparative examples C1 and C2 in the table above, the powder feeding rate affects the amount of powder entering the flame. When the powder feeding rate is less than 15 g / min, the coating is prone to "overheating" cracks, and the coating will develop cracks and the fluorescence peak intensity will increase. When the powder feeding rate is greater than 35 g / min, the particles are not heated for a long time, the number of unmelted particles increases, the porosity increases, and the fluorescence peak intensity increases.

[0052] Based on the comparative examples D1 and D2 in the table above, the spraying distance affects the temperature and kinetic energy of the particles when they reach the substrate surface. When the spraying distance is less than 150 mm, the particles are not fully melted. When the spraying distance is greater than 200 mm, the flight distance is too long, the temperature of the molten particles decreases, the crystal quality decreases, and the fluorescence peak intensity increases.

[0053] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A method for preparing a yttrium oxide coating to suppress fluorescence defects, characterized in that, include: Provides purity greater than 99.99%. The powder has a particle size of 15μm-45μm. Calcination Powder, calcined at a temperature greater than or equal to 800℃, and calcined for a time greater than or equal to 2 hours; Calcinated Yttrium oxide coating is formed using powder as raw material and plasma spraying process. During plasma spraying, the spraying distance is between 150-200mm and the powder feeding rate is between 20-30g / min.

2. The method for preparing a yttrium oxide coating to suppress fluorescence defects according to claim 1, characterized in that, Provided Powder, with a particle size between 15μm and 45μm.

3. The method for preparing a yttrium oxide coating to suppress fluorescence defects according to claim 1, characterized in that, During plasma spraying, the argon flow rate is between 50-60 NLPM and the hydrogen flow rate is between 5-15 NLPM.

4. The method for preparing a yttrium oxide coating to suppress fluorescence defects according to claim 1, characterized in that, Before plasma spraying, the substrate should be preheated to 200°C.

5. The method for preparing a yttrium oxide coating to suppress fluorescence defects according to claim 1, characterized in that, The thickness of the yttrium oxide coating ranges from 5 μm to 80 μm.

6. The method for preparing a yttrium oxide coating to suppress fluorescence defects according to claim 1, characterized in that, After plasma spraying, the coating is further annealed; wherein the annealing temperature is between 900-1200℃, and the heating and cooling rates are ≤5℃ / min.

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