METHOD OF MANUFACTURING PLASMA-RESISTANT COATING FILM AND PLASMA-RESISTANT MEMBER FORMED THEREBY

Abstract

The present invention relates to a method of manufacturing a plasma-resistant coating film, including (1) forming a first rare-earth metal compound coating layer by subjecting a first rare-earth metal compound to thermal-spray coating on a coating object, (2) polishing the surface of the first rare-earth metal compound coating layer formed in step (1), and (3) forming a second rare-earth metal compound coating layer by subjecting a second rare-earth metal compound to aerosol deposition coating on the first rare-earth metal compound coating layer processed in step (2), the second rare-earth metal compound being the same component as the first rare-earth metal compound.

Claims

1. A method of manufacturing a plasma-resistant coating film, comprising: (1) forming a first rare-earth metal compound coating layer by subjecting a first rare-earth metal compound to thermal-spray coating on a coating object; (2) polishing a surface of the first rare-earth metal compound coating layer formed in step (1); and (3) forming a second rare-earth metal compound coating layer by subjecting a second rare-earth metal compound to aerosol deposition coating on the first rare-earth metal compound coating layer processed in step (2), wherein the second rare-earth metal compound is a same component as the first rare-earth metal compound.

2. The method of claim 1, wherein the first rare-earth metal compound coating layer has a thickness of 100 m to 300 m.

3. The method of claim 1, wherein the second rare-earth metal compound coating layer has a thickness of 1.0 m to 30 m.

4. The method of claim 1, wherein the first rare-earth metal compound is selected from the group consisting of yttria (Y.sub.2O.sub.3), yttrium fluoride (YF) and yttrium oxyfluoride (YOF).

5. The method of claim 1, wherein an average surface roughness of the first rare-earth metal compound coating layer through the polishing in step (2) is 0.1 m to 3.0 m.

6. The method of claim 1, wherein the second rare-earth metal compound coating layer has a porosity of 1 vol % or less.

7. A plasma-resistant member, comprising: a coating object requiring plasma resistance; and a composite plasma-resistant coating film formed on a surface of the coating object, wherein the plasma-resistant coating film comprises a first rare-earth metal compound coating layer and a second rare-earth metal compound coating layer, the first rare-earth metal compound coating layer is formed by subjecting a first rare-earth metal compound to thermal-spray coating and a surface of the first rare-earth metal compound coating layer is processed so as to have an average surface roughness of 0.1 m to 3.0 m, the second rare-earth metal compound coating layer is formed by subjecting a second rare-earth metal compound to aerosol deposition coating on the first rare-earth metal compound coating layer, and the second rare-earth metal compound is a same component as the first rare-earth metal compound.

8. The plasma-resistant member of claim 7, wherein the first rare-earth metal compound coating layer has a thickness of 100 m to 300 m.

9. The plasma-resistant member of claim 7, wherein the second rare-earth metal compound coating layer has a thickness of 1.0 m to 30 m.

10. The plasma-resistant member of claim 7, wherein the first rare-earth metal compound is selected from the group consisting of yttria (Y.sub.2O.sub.3), yttrium fluoride (YF) and yttrium oxyfluoride (YOF).

11. The plasma-resistant member of claim 7, wherein the second rare-earth metal compound coating layer has a porosity of 1 vol % or less.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0029] FIG. 1 schematically shows the structure of a plasma-resistant coating film including a first rare-earth metal compound coating layer and a second rare-earth metal compound coating layer according to the present invention and a process of manufacturing the same;

[0030] FIG. 2 is a scanning electron microscope (SEM) image of a plasma-resistant coating film including a first yttria coating layer and a second yttria coating layer manufactured in Example 1; and

[0031] FIG. 3 shows images after etching testing of (a) alumina (Al.sub.2O.sub.3), (b) quartz, (c) yttria (Y.sub.2O.sub.3, bulk), (d) yttria (Y.sub.2O.sub.3, AD coating), and (e) yttria (Y.sub.2O.sub.3, APS).

DESCRIPTION OF SPECIFIC EMBODIMENTS

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those typically understood by those skilled in the art to which the present invention belongs. Generally, the nomenclature used herein is well known in the art and is typical.

[0033] As used herein, when any part is said to include any element, this does not mean that other elements are excluded, and such other elements may be further included unless otherwise specifically mentioned.

[0034] An aspect of the present invention pertains to a method of manufacturing a plasma-resistant coating film, including (1) forming a first rare-earth metal compound coating layer by subjecting a first rare-earth metal compound to thermal-spray coating on a coating object, (2) polishing the surface of the first rare-earth metal compound coating layer formed in step (1), and (3) forming a second rare-earth metal compound coating layer by subjecting a second rare-earth metal compound to aerosol deposition coating on the first rare-earth metal compound coating layer processed in step (2), the first rare-earth metal compound in step (1) and the second rare-earth metal compound in step (2) being the same component.

[0035] More specifically, the method of manufacturing the plasma-resistant coating film according to the present invention includes, as shown in FIG. 1, forming a first rare-earth metal compound coating layer 110 through thermal-spray coating on a coating object 100, subjecting the first rare-earth metal compound coating layer 110 to surface processing so that the average surface roughness thereof is 0.1 m to 3.0 m, and forming a second rare-earth metal compound coating layer 120 on the surface-processed first rare-earth metal compound coating layer 110 through aerosol deposition coating (AD coating) having high coating density, thereby obtaining a plasma-resistant coating film having high bonding force between coating layers and high plasma resistance.

[0036] In the method of manufacturing the plasma-resistant coating film according to the present invention, the first rare-earth metal compound coating layer 110 is formed by subjecting the first rare-earth metal compound to thermal-spray coating on the coating object 100 [step (1)].

[0037] The coating object 100 on which the first rare-earth metal compound coating layer is formed may be a plasma device part that is applied to the inside of a plasma device, such as an electrostatic chuck, a heater, a chamber liner, a shower head, a boat for CVD, a focus ring, a wall liner, etc., and the material for the coating object may include, but is not limited to, metal such as iron, magnesium, aluminum, alloys thereof, etc., ceramic, such as SiO.sub.2, MgO, CaCO.sub.3, alumina, etc., a polymer, such as polyethylene terephthalate, polyethylene naphthalate, polypropylene adipate, polyisocyanate, etc., and the like.

[0038] Moreover, the coating object 100 is subjected to surface sanding treatment and is thus imparted with surface roughness of a certain level, and also, adhesion between the coating object and the first rare-earth metal compound coating layer that is subsequently formed may be enhanced.

[0039] For example, if the surface roughness of the coating object 100 through sanding treatment is less than 1 m, adhesion between the coating object and the first rare-earth metal compound coating layer that is subsequently formed may decrease, undesirably facilitating peeling of the first rare-earth metal compound coating layer from the coating object due to external impact. On the other hand, if the surface roughness of the coating object through sanding treatment exceeds 8 m, it may affect the surface roughness of the first rare-earth metal compound coating layer that is subsequently formed, and thus the second rare-earth metal compound coating layer may not be formed at a uniform thickness on the first rare-earth metal compound coating layer, which is undesirable. In the present embodiment, the coating object may be subjected to sanding treatment so as to have a surface roughness corresponding to an average center roughness of about 1 m to 8 m.

[0040] In order to form the first rare-earth metal compound coating layer 110 on the coating object, any process may be applied without limitation, so long as it is thermal-spray coating for forming a coating layer that satisfies requirements such as high bonding force between the coating object and the coating layer and high corrosion resistance. Preferably, a plasma thermal-spray coating process is performed in order to attain high hardness of the coating layer and high electrical resistance.

[0041] In step (1), the first rare-earth metal compound coating layer 110 is a layer that is formed by subjecting the first rare-earth metal compound to thermal-spray coating on the coating object 100, and preferably has a thickness of 100 m to 300 m. If the thickness of the first rare-earth metal compound coating layer is less than 100 m, voltage resistance may decrease, which is undesirable. On the other hand, if the thickness thereof exceeds 300 m, the processing time may increase, undesirably lowering productivity.

[0042] The first rare-earth metal compound may be selected from the group consisting of yttria (Y.sub.2O.sub.3), yttrium fluoride (YF) and yttrium oxyfluoride (YOF), and is preferably yttria (Y.sub.2O.sub.3).

[0043] The first rare-earth metal compound, which constitutes the first rare-earth metal compound coating layer, has high resistance to the plasma when exposed thereto during semiconductor processing, thereby ensuring voltage resistance and plasma corrosion resistance during semiconductor processing when applied to a semiconductor device part requiring corrosion resistance, such as a semiconductor-etching device.

[0044] The first rare-earth metal compound coating layer 110 is subjected to surface processing so that the average surface roughness thereof is 0.1 m to 3.0 m [step (2)].

[0045] In the method of manufacturing the plasma-resistant coating film according to the present invention, step (2) is processing the surface of the first rare-earth metal compound coating layer formed in step (1) so as to have an average surface roughness of 0.1 m to 3.0 m. Specifically, the first rare-earth metal compound coating layer formed in step (1) is subjected to grinding so as to have a uniform thickness and then to surface roughening so that the surface of the first rare-earth metal compound coating layer has an average surface roughness of 0.1 m to 3.0 m. Here, the above processing may be performed through polishing using a diamond pad, but is not limited thereto. In addition to polishing using the diamond pad, polishing may be performed through chemical mechanical polishing (CMP) or other polishing procedures.

[0046] The surface of the first rare-earth metal compound coating layer formed in step (1) may be roughened through the above processing so as to have an average surface roughness of 0.1 m to 3.0 m, thereby enhancing adhesion between the first rare-earth metal compound coating layer and the second rare-earth metal compound coating layer. If the average surface roughness of the metal compound coating layer exceeds 3.0 m, the surface roughness may be excessively increased, making it difficult to form a desired coating layer on the first rare-earth metal compound coating layer, which causes layer peeling.

[0047] In order to form a denser coating layer on the first rare-earth metal compound coating layer 110, the second rare-earth metal compound coating layer 120 is formed by depositing the second rare-earth metal compound using aerosol deposition coating (AD coating) [step (3)].

[0048] The second rare-earth metal compound coating layer 120 is a high-density rare-earth metal compound layer having a porosity of 1 vol % or less formed on the first rare-earth metal compound coating layer through aerosol deposition coating, and preferably has a thickness of 1 m to 30 m and a surface roughness corresponding to an average center roughness of 0.1 m to 3.0 m. The surface roughness of the second rare-earth metal compound coating layer is determined by the initial surface roughness of the substrate and the increased thickness of the coating layer.

[0049] As the porosity of the second rare-earth metal compound coating layer increases, the mechanical strength of the plasma-resistant coating film that is ultimately formed may deteriorate, which is undesirable. Thus, it is preferred that the second rare-earth metal compound coating layer have low porosity and be dense in order to ensure the mechanical strength of the plasma-resistant coating film and the electrical properties thereof.

[0050] If the thickness of the second rare-earth metal compound coating layer is less than 1 m, the thickness thereof is excessively low, making it difficult to ensure plasma resistance in a plasma environment. On the other hand, if the thickness of the second rare-earth metal compound coating layer exceeds 30 m, peeling may occur due to residual stress of the coating layer, and may also take place even during processing. Furthermore, overuse of the rare-earth metal compound is uneconomical.

[0051] Moreover, as the surface roughness of the second rare-earth metal compound coating layer, which is the surface layer of the plasma-resistant coating film according to the present invention, is lower, the generation of particles may be reduced.

[0052] In order to form the second rare-earth metal compound coating layer, aerosol deposition coating may be conducted in a manner in which a second rare-earth metal compound powder having a particle size of 0.1 m to 20 m is placed in an aerosol chamber and the coating object is seated in a deposition chamber. Here, the second rare-earth metal compound powder is applied in the aerosol chamber, and is incident into the aerosol chamber through argon gas and is thus aerosolized. The carrier gas may include, in addition to argon gas, compressed air, inert gas such as hydrogen (H.sub.2), helium (He) or nitrogen (N.sub.2), and the like. The second rare-earth metal compound powder is sucked together with the carrier gas into the deposition chamber due to the difference in pressure between the aerosol chamber and the deposition chamber, and is sprayed at a high speed onto the coating object via a nozzle. Thereby, the second rare-earth metal compound is deposited through the above spraying, thus forming a high-density second rare-earth metal compound coating layer. The area of the second rare-earth metal compound coating layer that is deposited is controllable to a desired size by moving the nozzle from side to side, and the thickness thereof is also determined in proportion to the deposition time, that is, the spraying time.

[0053] The second rare-earth metal compound coating layer 120 may be formed by stacking the second rare-earth metal compound through two or more aerosol deposition coating processes.

[0054] In the present invention, the second rare-earth metal compound is the same as the first rare-earth metal compound, thereby increasing the bonding force between the first rare-earth metal compound coating layer and the second rare-earth metal compound coating layer to thus minimize the peeling of the coating layer and the generation of particles during the manufacturing process and the contamination of a wafer due thereto.

[0055] The aerosol deposition coating is preferably conducted using medical-grade compressed air. The use of medical-grade compressed air is effective at preventing a problem in which aerosolization does not occur due to moisture typically contained in air and also preventing impurities such as oil in air from being incorporated in the film during aerosol deposition coating.

[0056] The method of manufacturing the plasma-resistant coating film according to the present invention enables the formation of a uniform thin film on the 3D surface of the plasma-resistant member through one-stop coating. Conventionally, section coating is performed depending on the shape of the product, and thus the coating layer at the boundary of the sections is non-uniform, but when the one-stop coating process proceeds, the boundary coating layer may be manufactured in the form of a uniform thin film. Accordingly, it is possible to form a uniform coating film on various types of substrates when manufacturing a coating film using a one-stop coating process.

[0057] Another aspect of the present invention pertains to a plasma-resistant member including a coating object requiring plasma resistance and a composite plasma-resistant coating film formed on the surface of the coating object, in which the plasma-resistant coating film includes a first rare-earth metal compound coating layer and a second rare-earth metal compound coating layer, the first rare-earth metal compound coating layer is formed by subjecting a first rare-earth metal compound to thermal-spray coating, the surface of the first rare-earth metal compound coating layer is processed so as to have an average surface roughness of 0.1 m to 3.0 m, the second rare-earth metal compound coating layer is formed by subjecting a second rare-earth metal compound to aerosol deposition coating on the first rare-earth metal compound coating layer, and the first rare-earth metal compound and the second rare-earth metal compound are the same component.

[0058] A better understanding of the present invention will be given through the following examples. However, the following examples are merely set forth to illustrate the present invention, and are not to be construed as limiting the present invention.

COMPARATIVE EXAMPLES 1 to 3

[0059] Alumina (Al.sub.2O.sub.3), quartz, and yttria (Y.sub.2O.sub.3), which were in a solid phase, were used without processing in Comparative Example 1, Comparative Example 2 and Comparative Example 3, respectively.

COMPARATIVE EXAMPLE 4

[0060] A yttria coating layer having a thickness of 10 (5) m was formed by aerosolizing a yttria (Y.sub.2O.sub.3) powder in an aerosol chamber in a vacuum at room temperature and then subjecting the aerosolized yttria (Y.sub.2O.sub.3) powder to physical collision with argon gas on a substrate using a difference in pressure between the aerosol chamber and the deposition chamber.

COMPARATIVE EXAMPLE5

[0061] A yttria coating layer having a thickness of 100 m was formed by subjecting a yttria (Y.sub.2O.sub.3) thermal-spray coating powder having an average particle size of 30 m to plasma thermal-spray coating (helium and argon processing gases, 3000 K heat source) on a substrate.

COMPARATIVE EXAMPLE6

[0062] 6-1: Formation of Alumina Coating Layer An alumina coating layer having a thickness of 100 m was formed by subjecting an alumina (Al.sub.2O.sub.3) thermal-spray coating powder having an average particle size of 30 m to plasma thermal-spray coating (helium and argon processing gases, 3000 K heat source) on a substrate.

[0063] 6-2: Surface Processing of Alumina Coating Layer

[0064] The alumina coating layer was subjected to surface processing through polishing using a diamond pad so that the surface roughness thereof was 3 m or less.

[0065] 6-3: Formation of Yttria Coating Layer

[0066] A yttria coating layer having a thickness of 10 (5) m was formed by aerosolizing a yttria (Y.sub.2O.sub.3) powder in an aerosol chamber in a vacuum at room temperature and then subjecting the aerosolized yttria (Y.sub.2O.sub.3) powder to physical collision with argon gas on the surface-processed alumina coating layer using a difference in pressure between the aerosol chamber and the deposition chamber.

EXAMPLE 1

[0067] 1-1: Formation of First Yttria Coating Layer

[0068] A first yttria coating layer having a thickness of 100 m was formed by subjecting a yttria (Y.sub.2O.sub.3) thermal-spray coating powder having an average particle size of 30 m to plasma thermal-spray coating (helium and argon processing gases, 3000 K heat source) on a substrate.

[0069] 1-2: Surface Processing of First Yttria Coating Layer

[0070] The first yttria coating layer was subjected to surface processing through polishing using a diamond pad so that the surface roughness thereof was 3 m or less.

[0071] 1-3: Formation of Second Yttria Coating Layer

[0072] A second yttria coating layer having a thickness of 10 m was formed by aerosolizing a yttria (Y.sub.2O.sub.3) powder in an aerosol chamber in a vacuum at room temperature and then subjecting the aerosolized yttria (Y.sub.2O.sub.3) powder to physical collision with argon gas on the surface-processed first yttria coating layer using a difference in pressure between the aerosol chamber and the deposition chamber.

TEST EXAMPLE 1

[0073] The plasma-etching rates of the coating films manufactured in Comparative Examples and Example of the present invention were measured using Unaxis, VLICP (etching: CF.sub.6/C.sub.4F.sub.8/CH.sub.2F.sub.2/CF.sub.4/O.sub.2/Ar, flow rate: 30/5/10 sccm, chamber pressure: 0.1 torr, power: 5000 W). The results thereof are shown in Tables 1 and 2 below.

TABLE-US-00001 TABLE 1 Coating Etching rate No. Type Material (m/hr) Comparative Bulk Al.sub.2O.sub.3 9.01 Example 1 Comparative Bulk Quartz 41.06 Example 2 Comparative Bulk Y.sub.2O.sub.3 0.41 Example 3 Comparative AD coating Y.sub.2O.sub.3 2.28 Example 4 Comparative Thermal-spray Y.sub.2O.sub.3 3.00 Example 5 coating

[0074] As is apparent from Table 1, Comparative Example 4 exhibited a low plasma-etching rate compared to Comparative Example 5, indicating that the plasma resistance of the coating film formed through aerosol deposition coating for forming a dense thin film was higher than that of the coating film formed through thermal-spray coating. On the other hand, Comparative Example 3 exhibited a low etching rate compared to Comparative Examples 1 and 2, which shows the difference in plasma resistance depending on the kind of material, indicating that yttria has higher plasma resistance than alumina or quartz.

TABLE-US-00002 TABLE 2 First coating layer Second Thermal- coating spray layer Comparison of total etching coating AD coating time to completely remove No. (100 m) (10 m) A and B coating layers Example 1 Y.sub.2O.sub.3 Y.sub.2O.sub.3 A + B 37 min Comparative Al.sub.2O.sub.3 Y.sub.2O.sub.3 A + B 6 min Example 6

[0075] As is apparent from Table 2, Example 1 exhibited a low plasma-etching rate compared to Comparative Example 6. This is deemed to be because the high etching rate of the coating film manufactured in Comparative Example 6 is due to the first coating layer made of amorphous alumina. The time taken to completely remove the coating film including the first coating layer made of yttria having higher plasma resistance, which was manufactured in Example 1, was over 6 times as long as that of the coating film manufactured in Comparative Example 6.

[0076] Although specific embodiments of the present invention have been disclosed in detail as described above, it will be obvious to those skilled in the art that the description is merely of preferable exemplary embodiments and is not to be construed to limit the scope of the present invention. Therefore, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof.