High-corrosion-resistance yttrium oxide coating for semiconductor equipment and preparation method of high-corrosion-resistance yttrium oxide coating

Abstract

The invention discloses a high-corrosion-resistance yttrium oxide coating for semiconductor equipment and a preparation method of the high-corrosion-resistance yttrium oxide coating, and belongs to the technical field of coatings. According to the high-corrosion-resistance yttrium oxide coating for the semiconductor equipment and the preparation method of the high-corrosion-resistance yttrium oxide coating, a SiC transition layer is formed on the surface of a carbon-containing matrix; and an yttrium oxide ceramic coating is deposited on the SiC transition layer in an SPPS plasma spraying mode. The SiC transition layer is firstly formed on the carbon-containing substrate, then the Y2O3 coating is deposited through solution precursor plasma spraying, and a structure with both interface stability and surface protection is formed. SiC is thermally compatible with a substrate, so that undercut, warping and stripping can be inhibited; the dense Y2O3 layer can form a non-volatile protective phase in fluorine-containing / chlorine-containing plasma, thereby reducing the material removal rate and reducing particle release.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating technology, in particular to a high-erosion-resistant yttrium oxide coating for semiconductor equipment and a preparation method thereof. BACKGROUND

[0002] In the process of semiconductor dry etching and chemical vapor deposition, active plasma containing fluorine and chlorine is often used in the process chamber, such as a mixture of carbon tetrafluoride and oxygen. The chamber exposure component is subjected to the chemical action of high-energy ions and free radicals, sputtering erosion, and thermal load superposition for a long time, and is prone to failure modes such as rapid removal, surface powdering, interface cracking, and particle release. Graphite is widely used due to its high temperature resistance, good thermal conductivity, and easy processing, but it will be severely corroded in fluorine-containing plasma and generate volatile fluorocarbons, which causes the following problems: shortening of the service life of the component, frequent replacement, and increase in downtime and maintenance costs; corrosion products and falling particles pollute the wafer, resulting in a decrease in yield; changes in the size and surface topography of the component change the electric field and airflow distribution in the chamber, resulting in poor process repeatability.

[0003] To suppress the above failures, the industry attempts to deposit a rare earth oxide protective layer on the surface of the carbon-containing substrate. Yttrium oxide is of great concern because it can generate a non-volatile protective product in a fluorine-containing environment. However, the yttrium oxide coating prepared by conventional processes such as atmospheric plasma spraying has the following shortcomings: first, the thermal expansion coefficients of the coating and the graphite substrate do not match, and the interface is not well bonded, which is prone to cracking, warping, and peeling under thermal cycling and ion bombardment; second, the coating has many pores and microcracks, and the corrosion medium can reach the interface along the channel to cause corrosion under the coating; third, the phase structure and density are difficult to stabilize for a long time, and local amorphization or phase transition can weaken the protection ability in a fluorine-containing medium. Therefore, there is an urgent need for a transition layer that can be constructed on a carbon-containing substrate to match the chemical and thermal properties, and a preparation method for a dense and fine-grained yttrium oxide coating, to simultaneously reduce material removal rate, reduce particle release, and improve process stability under typical plasma conditions. SUMMARY

[0004] In view of the above-mentioned defects of the prior art, the present application provides a high-erosion-resistant yttrium oxide coating for semiconductor equipment and a preparation method thereof.

[0005] The specific technical solutions are as follows: A preparation method of a high-erosion-resistant yttrium oxide coating for semiconductor equipment, comprising: (1) forming a SiC transition layer on the surface of a carbon-containing substrate; and (2) depositing a yttrium oxide ceramic coating on the SiC transition layer by SPPS plasma spraying.

[0006] SiC transition layer is more compatible with carbon-containing substrate in chemistry and thermodynamics, which can be used as a stable interface and barrier to reduce the undercut, warping and peeling of subsequent coatings under thermal cycling and plasma action, and provide a uniform, clean and roughness-controlled bearing surface for yttrium oxide layer, thereby improving overall resistance and use stability. Solution precursor plasma spraying can deposit yttrium oxide with smaller feature size and higher density; placed on the SiC transition layer, a protective coating with stable bonding, few defects and suitable for plasma working conditions can be obtained.

[0007] Preferably, The step (1) comprises: a) providing a silicon-containing reaction system, the reaction system comprising metal silicon powder (Si powder), halogenated penetration agent and silicon carbide; under the action of heating and halogen chemical potential, the silicon powder is converted into transportable silicon halide and deposited on the surface by decomposition, generating continuous SiC in situ; the halogenated penetration agent removes the oxide layer and impurities, and increases the nucleation density; the inert SiC particles act as dilution and heat conduction aggregate, stabilizing the powder bed temperature field and mass transfer, and facilitating uniform layer thickness.

[0008] b) tightly contacting or completely embedding the carbon-containing substrate with the reaction system in a non-oxidizing environment; c) heating the substrate to a temperature sufficient to generate silicon carbide on its surface in situ and maintaining for a period of time, and then cooling, thereby forming a SiC transition layer on the surface of the substrate.

[0009] The halogenated penetration agent in step a) is at least one of ammonium chloride, ammonium bromide, ammonium iodide, aluminum trichloride, zinc chloride, ammonium fluoride and fluoro-chloride ammonium. Further, the halogenated penetration agent is ammonium chloride and / or aluminum trichloride; further, the halogenated penetration agent is ammonium chloride and aluminum trichloride, and the mass ratio of the two is 1: (2-4).

[0010] The step b) is achieved by any one of completely embedding, tightly contacting in a bag or being placed adjacent to the reaction system in a gas-permeable container.

[0011] The step c) is carried out in an inert gas, inert / reducing mixed gas or reduced pressure environment.

[0012] The heating condition of step c) meets the requirement of generating SiC layer on the surface of the carbon-containing substrate.

[0013] In step a), the mass percentage of metal silicon powder in the silicon reaction system is 20-40 wt%, the mass percentage of halogenated penetration agent is 0.4-1.0 wt%, and the balance is silicon carbide, based on the total mass of the silicon reaction system.

[0014] Further preferably, the step a) is that the mass percentage of the metal silicon powder in the silicon reaction system is 18-36 wt%, the mass percentage of the silicon nitride is 2-4 wt%, the mass percentage of the halogenated permeation agent is 0.4-1.0 wt%, and the rest is silicon carbide. The silicon nitride is added in the silicon reaction system. The silicon nitride can participate in the formation of silicon halide under the halogen chemical potential, smooth the silicon flux, form a thin Si-C-N transition zone on the surface layer, improve the nucleation density and layer density, obtain a more uniform SiC transition layer, and improve the interface stability.

[0015] The heating condition of the step c) is that the temperature is raised to 1650-1750℃ under the protection of inert gas and the temperature is kept for 2-5 h.

[0016] The carbon-containing substrate in the step (1) is graphite.

[0017] The step (2) comprises the following steps: using the coordination aqueous solution as a spraying raw material, spraying the coordination aqueous solution on the carbon-containing substrate by using the SPPS plasma spraying mode, and depositing the yttrium oxide ceramic coating on the SiC transition layer. The coordination transparent solution inhibits hydrolysis and gelation, facilitates atomization and repeated pyrolysis, and the SPPS plasma spraying mode can obtain the yttrium oxide layer with stable combination and low porosity on the SiC transition layer.

[0018] The coordination aqueous solution in the step (2) is an aqueous solution containing soluble yttrium salt and organic carboxylic acid complexing agent. Further, the mass percentage of the soluble yttrium salt in the coordination aqueous solution is 35-42 wt%, and the mass percentage of the organic carboxylic acid complexing agent is 10-15 wt%. The soluble yttrium salt is selected from at least one of yttrium nitrate, yttrium chloride and yttrium acetate. The organic carboxylic acid complexing agent is selected from at least one of citric acid, tartaric acid, malic acid and lactic acid. The soluble yttrium salt and the organic carboxylic acid form a stable complex system, control the metal ion concentration and the complex ratio, reduce the porosity fluctuation in the atomization and pyrolysis process, and facilitate the obtaining of the dense and fine-grained yttrium oxide layer.

[0019] The step (2) further comprises a sand blasting roughening step for the carbon-containing substrate. The controlled roughening can improve the mechanical interlocking and the first layer spreading, reduce the interface defect sensitivity, and further improve the retention and repeatability of the coating under the thermal and plasma load.

[0020] The application further discloses a high-etch-resistance yttrium oxide coating for a semiconductor device, which is prepared by using the above method.

[0021] The present application forms a silicon carbide transition layer on the surface of a carbon-containing substrate first, and then deposits a yttrium oxide coating on the transition layer by solution precursor plasma spraying, to obtain a composite structure that takes into account the interface stability and surface protection. The silicon carbide transition layer has good compatibility with the substrate and higher thermal matching degree, which is conducive to inhibiting undercuts, warping and peeling under thermal cycling and plasma action, thereby improving the service stability of the coating; the yttrium oxide ceramic layer obtained on this basis has high density and is easy to form a difficult-to-volatilize protective phase in a plasma environment containing fluorine or chlorine, which can reduce the material removal rate and help reduce particle release. The two-step method is suitable for the surface of complex components, and the thickness and coverage uniformity of the coating can be easily controlled by process parameters, and is suitable for long-term stable application in semiconductor equipment. DETAILED DESCRIPTION

[0022] For ease of understanding, the numerical values and their value ranges involved in the present specification, unless otherwise explicitly limited, should be understood to include their endpoints and values reasonably close to the endpoints; the upper and lower limits of any numerical range, the endpoints of different ranges, and the single-point values given in the text can be combined to form new sub-ranges, which are also considered to be explicitly disclosed.

[0023] The raw materials, reagents and equipment not specifically mentioned in the present application are all commonly used in the art or can be prepared according to the disclosed methods; the difference in brand, purity or supply channel does not affect the implementation effect of the technical solutions of the present application, and all can be replaced equivalently within the technical concept of the present application.

[0024] The present application will be further described below in conjunction with specific examples. The examples are only used to illustrate the technical solutions and implementation modes of the present application and do not constitute a limitation on the protection scope. Equivalent replacements, modifications or combinations made by those of ordinary skill in the art without departing from the spirit and essence of the present application shall fall within the protection scope of the present application.

[0025] The parameters and sources of some raw materials in the examples are as follows: The carbon-containing substrate graphite is high-purity graphite ISO-63 grade, specifically, Oriental graphite ISO-63.

[0026] Metallic silicon powder, Si powder, purity 99.9wt%, D 50 =10µm.

[0027] Silicon carbide powder, α-SiC, purity 99.9wt%, D 50 =5µm.

[0028] Example 1: A carbon-containing matrix graphite was processed into a sample with a size of 50 mm x 50 mm x 5 mm. The sample was sequentially cleaned with acetone and anhydrous ethanol by ultrasonic cleaning for 5 min, and then was dried in a 80°C air-drying oven for 15 min. After taking out, the sample was wiped with a dust-free cloth to remove the surface residual solvent and particles, and a clean graphite sample was obtained.

[0029] The silicon metal powder 30.00 g, silicon carbide powder 69.40 g and ammonium chloride 0.60 g were placed in a agate grinding container, and dry ball milling was carried out at 200 rpm for 30 min to obtain a uniform mixed powder; the obtained mixed powder was collected through a 100 mesh sieve for standby, and a silicon-containing reaction system was obtained.

[0030] A φ80 mm x 100 mm dense graphite crucible was first laid with a 10 mm thick bottom layer of the above-mentioned silicon-containing reaction system, and a clean graphite sample was placed in the center of the bottom layer. Then, the silicon-containing reaction system was continuously added until it uniformly covered the upper surface of the sample and formed a top layer on it, thereby achieving complete embedding of the sample in the silicon-containing reaction system. In order to balance the gas permeation atmosphere and safe exhaust, a quartz cover with two φ1 mm micropores was placed on the crucible.

[0031] The filled crucible was placed in a high-temperature furnace with inert gas inlet capability, and argon was continuously introduced from room temperature at a constant flow rate of 200 sccm. The temperature was raised to 800°C at a rate of 10°C / min and held for 30 min to complete moisture removal and pre-reaction of the halogenating agent. Then, the temperature was raised to 1700°C at a rate of 8°C / min and held for 3 h. Then, the crucible and graphite sample were taken out after the furnace was cooled to 200°C.

[0032] After the cooled graphite sample was taken out, the surface residual powder was lightly brushed and wiped with anhydrous ethanol, and then dried at 80°C for 10 min. The obtained graphite sample had a SiC transition layer on the surface with an average thickness of 28 µm. Through the above steps, the formation of a SiC transition layer on the surface of the carbon-containing matrix graphite was finally completed.

[0033] The above-mentioned graphite sample was sandblasted for roughening. Specifically, white corundum F60 sand was used, the spraying pressure was 0.5 MPa, the nozzle-to-workpiece distance was 100 mm, the incident angle was 75 degrees, the walking speed was 300 mm / s, and the treatment time was 60 seconds. After sandblasting, the surface was wiped with anhydrous ethanol and dried at 80°C for 10 minutes.

[0034] A coordination aqueous solution of yttrium nitrate 38wt% and citric acid 12wt% was prepared with a volume of 100 ml; the solution was filtered through a 0.22 µm polytetrafluoroethylene filter membrane, and stood for 30 min to remove bubbles for standby.

[0035] The above coordination aqueous solution is sprayed onto the graphite sample by SPPS plasma spraying. The specific steps are as follows: a direct current plasma spray gun is used, and an axial liquid inlet nozzle is used, the plasma working gas is argon 45 slpm and hydrogen 10 slpm, and the spray gun power is 45 kW. The coordination aqueous solution is quantitatively delivered by a gear pump at a rate of 6.0 mL / min, the spraying time is 7 minutes, argon is used as the atomizing gas, the gage pressure is 0.25 MPa; the spraying distance is 80 mm, the walking speed is 300 mm / s, and the interpass overlap is 40%. The surface temperature of the graphite substrate is controlled at 450 DEG C by infrared temperature measurement during the spraying process, and the graphite substrate is preheated by the plasma plume for 30 seconds before spraying. After spraying, the sample is placed in a box furnace, heated at 1200 DEG C for 120 minutes in an argon atmosphere, cooled to 200 DEG C in the furnace, and then cooled to room temperature. Through the above steps, the yttrium oxide ceramic coating is finally deposited on the SiC transition layer of the carbon-containing substrate graphite by the above SPPS plasma spraying method.

[0036] Example 2: The only difference from Example 1 is that the silicon-containing reaction system is different, specifically: Metallic silicon powder 30.00 g, silicon carbide powder 69.40 g, and aluminum chloride 0.60 g are placed in a agate grinding container, dry ball milling at 200 rpm for 30 min to obtain a uniform mixture of powders; the obtained mixed powder is collected through a 100 mesh sieve for standby, to obtain a silicon-containing reaction system.

[0037] Example 3: The only difference from Example 1 is that the silicon-containing reaction system is different, specifically: Metallic silicon powder 30.00 g, silicon carbide powder 69.40 g, ammonium chloride 0.15 g, and aluminum chloride 0.45 g are placed in a agate grinding container, dry ball milling at 200 rpm for 30 min to obtain a uniform mixture of powders; the obtained mixed powder is collected through a 100 mesh sieve for standby, to obtain a silicon-containing reaction system.

[0038] Example 4: The only difference from Example 1 is that the silicon-containing reaction system is different, specifically: Metallic silicon powder 30.00 g, silicon carbide powder 69.40 g, and ammonium fluoride 0.60 g are placed in a agate grinding container, dry ball milling at 200 rpm for 30 min to obtain a uniform mixture of powders; the obtained mixed powder is collected through a 100 mesh sieve for standby, to obtain a silicon-containing reaction system.

[0039] Example 5: The only difference from Example 1 is that the silicon-containing reaction system is different, specifically: Put metal silicon powder 30.00 g, silicon carbide powder 69.40 g, ammonium fluoride 0.15 g, and aluminum chloride 0.45 g into a agate grinding container, dry ball mill at 200 rpm for 30 min to obtain a uniform mixture of powder; the obtained mixed powder is collected through a 100 mesh sieve for standby, to obtain a silicon-containing reaction system.

[0040] Example 6: The only difference with Example 1 is that the silicon-containing reaction system is different, specifically: Put metal silicon powder 27.00 g, silicon nitride 3.00 g, silicon carbide powder 69.40 g, ammonium chloride 0.15 g, and aluminum chloride 0.45 g into a agate grinding container, dry ball mill at 200 rpm for 30 min to obtain a uniform mixture of powder; the obtained mixed powder is collected through a 100 mesh sieve for standby, to obtain a silicon-containing reaction system.

[0041] Blank example: High-purity graphite ISO-63 grade is selected as the carbon-containing matrix, which is processed into a sample of 50 mm x 50 mm x 5 mm. The sample is sequentially ultrasonically cleaned with acetone and anhydrous ethanol, with ultrasonic time of 5 min respectively, and then placed in a 80℃ air drying oven for drying for 15 min. After taking out, wipe with a dust-free cloth to remove the surface residual solvent and particles, to obtain a clean graphite sample.

[0042] Test example 1: The graphite samples of the examples and the blank example are loaded into a parallel capacitively coupled plasma reaction chamber, and the frequency of the chamber radio frequency power supply is 13.56 MHz. To evaluate the resistance of plasma test etching, a mixture of tetrafluoromethane and oxygen is used as the etching gas: tetrafluoromethane 40 sccm, oxygen 10 sccm. After evacuating to a base pressure below 5 mTorr, the gas is introduced and the evacuation bypass is closed. The chamber pressure is stabilized at 30 mTorr by a throttle valve; the table is heated to 80℃ and stabilized for 2 min; the radio frequency power supply is turned on, with a forward power of 600 W and a reflected power of less than 5% of the forward power. After ignition, continue to stabilize for 2 min, then start timing, and the total etching time is 60 min. To obtain a thickness step, before etching, a 5mm wide etch-resistant tape is attached to the sample test surface to form a shielding area and rolled 3 times with a pressure roller to make it tight. After etching, the sample is taken out and the tape is removed under nitrogen replacement to normal pressure. A white light interferometer is used to scan 1.0 mm of the step boundary vertically, with a sampling interval of 1 μm and a vertical resolution of not less than 1 nm. Record the height difference ΔH at this point; repeat the above scanning at 3 equally spaced positions on the sample surface and take the average as the ΔH of the sample. The calculation caliber of the etching rate is: calculate the etching rate = ΔH / 60, unit: nm / min.

[0043]

[0044] In the embedded permeation system, the halogenated permeation agent can convert the silicon source into volatile silicon halide and realize the gas-phase silicon transmission and in-situ layering on the surface of the carbon-containing substrate by providing a controllable halogen chemical potential. Taking the chlorine system as an example, ammonium chloride generates hydrogen chloride upon heating, and aluminum trichloride sublimates to generate a chloride gas with Lewis acidity, which can chlorinate the metallic silicon and the surface oxide layer thereof to form gas-phase species such as SiCl2 and SiCl4, and increase the effective silicon partial pressure, while removing the interfacial impurities and oxides, so as to promote the deposition of the nascent silicon on the surface of the substrate and the reaction of the silicon with carbon to generate a continuous SiC layer. The bromine and iodine systems have a relatively moderate halogenation rate, which is conducive to the inhibition of over-etching and pores; the fluorine system has a strong deoxidization ability, but mainly generates volatile SiF4, which may lead to insufficient silicon supply and porosity. Therefore, the introduction of the halogenated permeation agent can increase the silicon transmission rate, the interfacial cleanliness and the nucleation density, and obtain a continuous, dense and thickness-uniform SiC transition layer, which provides a stable substrate for the subsequent yttrium oxide coating. In addition, the ammonium chloride can rapidly activate and deoxidize at a medium or low temperature and increase the initial nucleation density, and the aluminum trichloride can continuously provide a chlorine potential and interfacial purification at a high temperature, which together make the SiC transition layer more dense and uniform, and have fewer pinholes, so as to reduce the material removal rate and the particle release under the plasma working condition. In Example 6, a small amount of silicon nitride is introduced into the silicon-containing reaction system, and the time-temperature complementary permeation of the ammonium chloride and the aluminum trichloride is adopted, so as to make the silicon supply more stable, the interface cleaner, form a dense, continuous and thickness-uniform SiC transition layer on the surface of the substrate, and improve the interfacial stability.

[0045] In summary, the above is only a preferred embodiment of the present application. It should be understood that those skilled in the art can make various equivalent changes and alternative solutions according to the technical concept of the present application without creative labor. Any technical solution obtained according to the technical concept of the present application through reasonable analysis, deduction or limited experiment shall be subject to the limitation of the claims and fall within the protection scope of the present application.

Claims

1. A method for producing a highly etch-resistant yttrium oxide coating for semiconductor devices, characterized by, The method comprises: (1) forming a SiC transition layer on the surface of a carbon-containing substrate; and (2) depositing a yttria ceramic coating on the SiC transition layer by SPPS plasma spraying. The step (1) comprises:

2. The method for preparing a highly corrosion-resistant yttrium oxide coating for semiconductor devices according to claim 1, characterized in that, a) providing a silicon-containing reaction system, which comprises metallic silicon powder, halogenated penetration promoter and silicon carbide; b) tightly contacting or completely embedding the carbon-containing substrate with the reaction system in a non-oxidizing environment; c) heating the substrate to a temperature sufficient to generate silicon carbide in situ on the surface of the substrate and maintaining for a period of time, and then cooling, so as to form a SiC transition layer on the surface of the substrate. The halogenated penetration promoter in the step a) is at least one of ammonium chloride, ammonium bromide, ammonium iodide, aluminum trichloride, zinc chloride, ammonium fluoride and fluoro-chloro ammonium.

3. The method for preparing a highly corrosion-resistant yttrium oxide coating for semiconductor devices according to claim 2, characterized in that, 4. The method for preparing a high-etch-resistant yttria coating for semiconductor equipment according to claim 2, wherein The step b) is achieved by any one of completely embedding, tightly contacting in a bag or being placed in a gas-permeable container adjacent to the reaction system; The step c) is performed in an inert gas, inert / reducing mixed gas or reduced pressure environment; The heating condition of the step c) meets the requirement of generating a SiC layer on the surface of the carbon-containing substrate. In the step a), the mass percentage of the metallic silicon powder in the silicon reaction system is 20-40 wt%, the mass percentage of the halogenated penetration promoter is 0.4-1.0 wt%, and the balance is silicon carbide, based on the total mass of the silicon reaction system.

5. The method for preparing a highly corrosion-resistant yttrium oxide coating for semiconductor devices according to claim 2, characterized in that, The heating condition of the step c) is to heat to 1650-1750 ℃ under the protection of inert gas and maintain for 2-5 h.

6. The method for preparing a highly corrosion-resistant yttrium oxide coating for semiconductor devices according to claim 2, characterized in that, The carbon-containing substrate in the step (1) is graphite.

7. The method of claim 1-6 for the preparation of a highly etch resistant yttrium oxide coating for semiconductor devices, characterized in that, The step (2) comprises: using a coordination aqueous solution as a spraying raw material, and spraying the coordination aqueous solution onto the carbon-containing substrate by SPPS plasma spraying, so as to deposit a yttria ceramic coating on the SiC transition layer.

8. The method of claim 1-6 for the preparation of a highly etch resistant yttrium oxide coating for semiconductor devices, characterized in that, The coordination aqueous solution in the step (2) is an aqueous solution containing soluble yttrium salt and organic carboxylic acid complexing agent.

9. The method for preparing a highly corrosion-resistant yttrium oxide coating for semiconductor devices according to claim 8, characterized in that, The yttria ceramic coating is prepared by the method according to any one of claims 1-9.

10. A high etch resistant yttrium oxide coating for semiconductor devices, characterized by, ​

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