Preparation method for improving etching resistance of yttrium oxide coating

Abstract

A preparation method for improving the etching resistance of an yttrium oxide coating comprises the following steps that after a high-purity sintered aluminum oxide substrate subjected to ultrasonic cleaning is fed into a coating process chamber, the coating process chamber is vacuumized to reach a preset vacuum degree; argon is introduced into the coating process chamber through the first gas ion source, and argon plasma is released after ionization so as to carry out plasma cleaning on the high-purity sintered alumina substrate; an yttrium oxide coating is deposited on the surface of the high-purity sintered aluminum oxide substrate subjected to plasma cleaning in a magnetron sputtering mode, meanwhile, oxygen is introduced into the coating process cavity through a second gas ion source, oxygen plasma is released after ionization, and oxygen vacancies are formed in the yttrium oxide coating. According to the method, the oxygen plasma is adopted to participate in the deposition process of the yttrium oxide coating, so that oxygen vacancies are formed in the yttrium oxide coating, and the physical etching resistance of the yttrium oxide coating is improved.

Description

Technical Field

[0001] The invention relates to the technical field of material surface treatment, and in particular to a preparation method for improving the etching resistance of an yttrium oxide coating. Background Art

[0002] At present, in the semiconductor industry, dense high-purity alumina ceramic coatings are often used to protect the surface of internal components in the etching process chamber. However, with the increase in plasma power and density, higher requirements are also placed on the etching resistance of the inner wall of the etching process chamber. Surface coating is an effective method to improve the plasma etching resistance of alumina ceramic materials.

[0003] In existing research, yttrium oxide is a material with excellent resistance to plasma etching and can effectively reduce the contamination particles generated by etching. Physical etching is an important part of plasma etching, and better resistance to plasma etching can be achieved by improving physical etching resistance. At present, the durability and reliability of equipment are mainly improved by preparing yttrium oxide coating on the surface of aluminum oxide, and further improving the physical etching resistance of yttrium oxide coating will effectively reduce the maintenance cost and replacement frequency of equipment parts. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a preparation method for improving the etching resistance of yttrium oxide coating, by forming oxygen vacancies in the yttrium oxide coating to improve the physical etching resistance of the yttrium oxide coating.

[0005] A preparation method for improving the etching resistance of an yttrium oxide coating comprises the following steps:

[0006] Step S10, after the high-purity sintered alumina substrate after ultrasonic cleaning is sent into the coating process chamber, the coating process chamber is evacuated to reach a preset vacuum degree;

[0007] Step S11, introducing argon gas into the coating process chamber through a first gas ion source, releasing argon plasma after ionization, so as to perform plasma cleaning on the high-purity sintered alumina substrate;

[0008] Step S12: Depositing a yttrium oxide coating on the surface of the high-purity sintered alumina substrate after plasma cleaning by magnetron sputtering, while introducing oxygen into the coating process chamber through a second gas ion source, releasing oxygen plasma after ionization, to form oxygen vacancies in the yttrium oxide coating.

[0009] Compared with the prior art, in the present invention, oxygen plasma is used to participate in the deposition process of the yttrium oxide coating to form oxygen vacancies in the yttrium oxide coating, thereby improving the physical etching resistance of the yttrium oxide coating.

[0010] Furthermore, in step S10, the high-purity sintered alumina matrix is ​​sintered by cold isostatic pressing, and the purity is 99.9%.

[0011] Furthermore, in step S10, the range of the vacuum degree is preset to 8×10 -4 ~1×10 -3 Pa.

[0012] Further, in step S11, the first gas ion source is a linear anode ion source, the voltage range is 500-800V, and the bombardment time is 10-30min.

[0013] Further, in step S12, the power source used for magnetron sputtering is a pulsed DC power source, the frequency range is 20-40kHz, the duty cycle is 30-80%, and the sputtering voltage range is 400-600V.

[0014] Furthermore, the thickness of the yttrium oxide coating is 1 to 5 μm.

[0015] Further, in step S12, the second gas ion source is a linear anode ion source, and the voltage is regulated in a constant voltage mode, the voltage range is 500-1000V, and the working time is the same as the deposition time.

[0016] Further, in step S12, the distance between the sputtering cathode and the surface to be coated is 7-10 cm. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of a method for preparing a yttrium oxide coating for improving its etching resistance;

[0018] FIG2( a ) is a physical picture of the yttrium oxide coating before physical etching without the participation of a gas ion source in the present invention;

[0019] FIG2( b ) is a physical picture of the yttrium oxide coating after physical etching without the participation of a gas ion source in the deposition of the present invention;

[0020] FIG2( c ) is a physical picture of the yttrium oxide coating deposited by a 500V gas ion source before physical etching in the present invention;

[0021] FIG2( d ) is a physical picture of the yttrium oxide coating deposited by a 500V gas ion source after physical etching in the present invention;

[0022] FIG2( e ) is a physical picture of the yttrium oxide coating deposited by a 1000 V gas ion source before physical etching in the present invention;

[0023] FIG2( f ) is a physical picture of the yttrium oxide coating deposited by a 1000V gas ion source after physical etching in the present invention;

[0024] Figure 3 This is a graph showing the change in oxygen vacancy concentration of the yttrium oxide coating under different oxygen plasma energies as characterized by EPR in the present invention;

[0025] FIG4( a ) is a SEM surface image of the yttrium oxide coating deposited without the participation of a gas ion source before physical etching in the present invention;

[0026] FIG4( b ) is a SEM surface image of the yttrium oxide coating after physical etching without the participation of a gas ion source in the present invention;

[0027] FIG4( c ) is a SEM surface image of the yttrium oxide coating deposited by a 500 V gas ion source before physical etching in the present invention;

[0028] FIG4( d ) is a SEM surface image of the yttrium oxide coating deposited by a 500 V gas ion source after physical etching in the present invention;

[0029] FIG4( e ) is a SEM surface image of the yttrium oxide coating deposited by a 1000 V gas ion source before physical etching in the present invention;

[0030] FIG4( f) is a SEM surface image of the yttrium oxide coating deposited by a 1000V gas ion source after physical etching in the present invention;

[0031] FIG5( a ) is a SEM cross-sectional view of the yttrium oxide coating deposited without the participation of a gas ion source before physical etching in the present invention;

[0032] FIG5( b ) is a SEM cross-sectional view of the yttrium oxide coating after physical etching without the participation of a gas ion source in the present invention;

[0033] FIG5( c ) is a SEM cross-sectional view of the yttrium oxide coating deposited by a 500 V gas ion source before physical etching in the present invention;

[0034] FIG5( d ) is a SEM cross-sectional view of the yttrium oxide coating deposited by a 500 V gas ion source after physical etching in the present invention;

[0035] FIG5( e ) is a SEM cross-sectional view of the yttrium oxide coating deposited by a 1000 V gas ion source before physical etching in the present invention;

[0036] FIG5( f) is a SEM cross-sectional view of the yttrium oxide coating deposited by a 1000V gas ion source after physical etching in the present invention;

[0037] Figure 6 A comparison diagram of the physical etching rates of yttrium oxide coatings with different oxygen vacancy concentrations in the present invention;

[0038] FIG. 7( a) is an XRD diagram of the yttrium oxide coating deposited without the participation of a gas ion source before and after physical etching in the present invention;

[0039] FIG7( b ) is an XRD diagram of the yttrium oxide coating deposited by a 500 V gas ion source before and after physical etching in the present invention;

[0040] FIG. 7( c ) is the XRD of the yttrium oxide coating deposited by a 1000V gas ion source before and after physical etching in the present invention.

[0041] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0042] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0043] See also Figure 1 In one embodiment of the present invention, a preparation method for improving the etching resistance of an yttrium oxide coating is provided, comprising the following steps:

[0044] Step S10, after the high-purity sintered alumina substrate after ultrasonic cleaning is sent into the coating process chamber, the coating process chamber is evacuated to reach a preset vacuum degree.

[0045] Specifically, in step S10, the high-purity sintered alumina matrix is ​​sintered by cold isostatic pressing, and the purity is 99.9%.

[0046] Specifically, the cleaning medium for ultrasonic cleaning is anhydrous ethanol, and after cleaning, it is dried in an inert gas nitrogen. After drying, the high-purity sintered alumina substrate is sent to a vacuum chamber.

[0047] In particular, the preset vacuum range is 8×10 -4 ~1×10 -3 Pa.

[0048] Step S11, introducing argon gas into the coating process chamber through a first gas ion source, releasing argon plasma after ionization, so as to perform plasma cleaning on the high-purity sintered alumina substrate.

[0049] It should be noted that in this step, the purpose of cleaning is to remove impurities (mainly including water molecules and organic matter) on the surface of the substrate and to increase the activation energy to enhance the membrane-substrate bonding force.

[0050] Specifically, in step S11, the first gas ion source is a linear anode ion source, the voltage range is 500-800V, and the bombardment time is 10-30min.

[0051] Step S12, using magnetron sputtering to deposit a yttrium oxide coating on the surface of the high-purity sintered alumina substrate after plasma cleaning, and at the same time, introducing oxygen into the coating process chamber through a second gas ion source, releasing oxygen plasma after ionization, so as to form oxygen vacancies in the yttrium oxide coating.

[0052] It should be noted that physical etching is a part of plasma etching in the semiconductor manufacturing process. The main principle is that the high-energy bombardment of the material surface by argon plasma in a vacuum environment causes material removal and damage. Physical etching resistance is manifested as resistance to argon plasma bombardment and is reflected by the etching rate. The higher the etching rate, the worse the etching resistance, and vice versa.

[0053] Specifically, the oxygen vacancies in the present application are point defects existing at the yttrium oxide atomic level, that is, vacancy defects formed by the absence of oxygen atoms, which can improve the physical etching resistance of the yttrium oxide coating. The present application uses oxygen plasma to participate in the deposition process of the yttrium oxide coating to form oxygen vacancies in the yttrium oxide coating, thereby improving the physical etching resistance of the yttrium oxide coating. And the constant voltage mode can be selected to regulate the voltage to regulate the energy of the oxygen plasma, thereby achieving the regulation of the oxygen vacancy concentration.

[0054] It should be noted that the introduction of oxygen vacancies in the present application is mainly due to the bombardment effect of oxygen ions during the deposition of the yttrium oxide coating. The introduction of oxygen vacancies causes changes in the bonding of oxygen atoms and yttrium atoms in the yttrium oxide lattice: 1. Due to the absence of oxygen atoms, the originally bonded yttrium atoms and the surrounding oxygen atoms are offset to varying degrees; 2. Due to the atomic offset, the lattice is distorted, and at the same time, the distance between the yttrium atoms and the oxygen atoms is reduced, and the bond length is shortened; 3. Due to the shortening of the bond length, the energy of the yttrium-oxygen bond is increased, and the energy required for bond breaking is also increased. Oxygen vacancies cause changes in the bonding of yttrium atoms and oxygen atoms, so that the destruction of the bonds by the high-energy bombardment of argon ions in physical etching requires greater energy and longer time, thereby improving the physical etching resistance of the yttrium oxide coating. Under the premise of not changing the cubic phase of the yttrium oxide coating, increasing the oxygen vacancy concentration can effectively improve the etching resistance of the yttrium oxide coating, as shown in the examples for details.

[0055] Specifically, in step S12, the power supply used for magnetron sputtering is a pulsed DC power supply with a frequency range of 20 to 40 kHz, a duty cycle of 30 to 80%, a sputtering voltage range of 400 to 600 V, and a thickness of the yttrium oxide coating of 1 to 5 μm.

[0056] Furthermore, the distance between the sputtering cathode and the surface to be coated is 7 to 10 cm.

[0057] Specifically, in step S12, the second gas ion source is a linear anode ion source, and the voltage is regulated in a constant voltage mode, the voltage range is 500-1000V, and the working time is the same as the deposition time.

[0058] Example

[0059] The preparation method of the present application is described in detail below with specific examples:

[0060] See also Figure 2(a)-2(f) , a high-purity sintered alumina substrate with a size of 30×30×3mm was placed in anhydrous ethanol for ultrasonic cleaning, taken out and dried with nitrogen, and then placed in a vacuum chamber and evacuated. The vacuum degree reached 1×10 -3 Pa started ion bombardment cleaning. A pulsed DC power supply was used for reactive sputtering at a duty cycle of 50%, a frequency of 20kHz and a power of 400W; oxygen was introduced from a gas ion source, and sputtering was carried out at 1000V, 500V and no voltage. After 2h of sputtering, the thickness of the yttrium oxide coating on the surface of high-purity sintered alumina was about 3μm. After deposition, the three yttrium oxide coating samples were physically etched under the same conditions at the same time, and the samples before and after etching were characterized by electron paramagnetic resonance (EPR), scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD).

[0061] See also Figure 3 , electron paramagnetic resonance (EPR) was used to characterize the oxygen vacancy concentrations of three different yttrium oxide coatings, showing a clear trend of change. EPR is a technique used to detect unpaired electrons in paramagnetic materials, allowing precise atomic-level data acquisition. When these materials are exposed to electromagnetic radiation in a specific magnetic field, they absorb radiation of a specific frequency. EPR is highly sensitive to identifying oxygen vacancies in metal oxide materials and provides direct information on the location of defects. The g tensor is an important data point that reflects the characteristics of defects. In materials containing oxygen vacancies, the g tensor is about 2.00. The EPR results show that different concentrations of oxygen vacancies are formed during the deposition of the coating. It can be seen that the EPR curves of the three samples are basically coincident, showing a main signal P1 with a main g tensor of 2.009, while the lower intensity signal P2 has a main g tensor of 2.007. As the energy of the oxygen plasma increases, the concentration of oxygen vacancies gradually increases.

[0062] See also Figure 4(a) to Figure 6, SEM was used to intuitively characterize the surface changes and cross-sectional thickness of three different yttrium oxide coatings before and after physical etching, and the corresponding etching rates were calculated to reflect the physical etching resistance. The SEM results show that the microstructures of the yttrium oxide coatings deposited by three different gas ion source voltages are almost the same. Before physical etching, the surface of the yttrium oxide coating presents a dense and uniform structure without obvious defects; after etching, the surface shows obvious signs of damage and the roughness increases. Before physical etching, the thickness of the three different yttrium oxide coatings gradually decreases with the increase of the gas ion source voltage, and after etching, they become thinner to varying degrees, which is caused by the improvement of physical etching resistance. After precise measurement of the thickness of three different yttrium oxide coating sections before and after physical etching, the results show that the thickness of the yttrium oxide coatings with no voltage, 500 and 1000V gas ion source before etching is 3220, 3170 and 2620 respectively. After 4h etching, the thickness is reduced to 2740, 2910 and 2460, and the thinning thickness is 480, 260 and 160 respectively. The etching rate is 2.00, 1.08 and 0.67nm / min respectively. The etching rate of the 500V sample is about 84.6% lower than that of the no voltage sample, and the etching rate of the 1000V sample is about 200% and 62.5% lower than that of the no voltage and 500V samples respectively.

[0063] See also Figures 7(a) to 7(c) , XRD was used to characterize the crystal structure of three different yttrium oxide coatings before and after physical etching. The results show that the yttrium oxide coatings deposited with three different gas ion source voltages have the same crystal phase, namely, c-type cubic phase crystal structure, indicating that the change in oxygen vacancy concentration has no significant effect on the crystal structure. However, with the increase of voltage, the peak intensity of this crystal phase gradually decreases, which also indicates that the oxygen vacancy concentration cannot increase indefinitely. In addition, with the increase of voltage, the grain size of the three different yttrium oxide coatings also gradually increases. After physical etching, the crystal phase of the three different yttrium oxide coatings did not change, and the grain size became slightly smaller.

[0064] In summary, the present invention uses different voltages to release oxygen plasmas of different energies to participate in the deposition of yttrium oxide coatings, thereby increasing the oxygen vacancy concentration of the yttrium oxide coating without changing the crystal structure, so that the physical etching rate is significantly reduced, thereby improving the physical etching resistance of the yttrium oxide coating, and providing a new production solution for the industrial production of more excellent plasma etching resistant yttrium oxide coatings.

[0065] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. The above-mentioned embodiments only express several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A preparation method for improving the etching resistance of yttrium oxide coating, characterized in that: The following steps are involved: Step S10, after the high-purity sintered alumina substrate after ultrasonic cleaning is sent into the coating process chamber, the coating process chamber is evacuated to reach a preset vacuum degree; Step S11, introducing argon gas into the coating process chamber through a first gas ion source, releasing argon plasma after ionization, so as to perform plasma cleaning on the high-purity sintered alumina substrate; Step S12, using magnetron sputtering to deposit a yttrium oxide coating on the surface of the high-purity sintered alumina substrate after plasma cleaning, and at the same time, introducing oxygen into the coating process chamber through a second gas ion source, releasing oxygen plasma after ionization, so as to form oxygen vacancies in the yttrium oxide coating.

2. The method for preparing a yttrium oxide coating for improving its etching resistance according to claim 1, characterized in that: In step S10, the high-purity sintered alumina substrate is sintered by cold isostatic pressing, and the purity is 99.9%.

3. The method for preparing a yttrium oxide coating for improving its etching resistance according to claim 1, characterized in that: In step S10, the range of the vacuum degree is preset to 8×10 -4 ~1×10 -3 Pa.

4. The method for preparing a yttrium oxide coating for improving its etching resistance according to claim 1, characterized in that: In step S11, the first gas ion source is a linear anode ion source, the voltage range is 500-800V, and the bombardment time is 10-30min.

5. The method for preparing a yttrium oxide coating for improving its etching resistance according to claim 1, characterized in that: In step S12, the power source used for magnetron sputtering is a pulsed DC power source with a frequency range of 20 to 40 kHz, a duty cycle of 30 to 80%, and a sputtering voltage range of 400 to 600V.

6. The method for preparing a yttrium oxide coating for improving its etching resistance according to claim 5, characterized in that: The thickness of the yttrium oxide coating is 1 to 5 μm.

7. The method for improving the etching resistance of yttrium oxide coating according to claim 1, characterized in that: In step S12, the second gas ion source is a linear anode ion source, and the voltage is regulated in a constant voltage mode, the voltage range is 500-1000V, and the working time is the same as the deposition time.

8. The method for improving the etching resistance of yttrium oxide coating according to any one of claims 1 to 7, characterized in that: In step S12, the distance between the sputtering cathode and the surface to be coated is 7-10 cm.

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