KR100966132B1 - Plasma-Resistant Ceramic Coated Substrate - Google Patents

Abstract

Disclosed is a ceramic coating having improved plasma resistance applied to a plasma processing apparatus. The ceramic coating is a ceramic to be applied to the plasma apparatus and the surface to be coated and has an etching rate of 13 to 25nm / min with respect to the plasma formed at 800W power, the content of pores is 0.1 to 1% It has a structure including a coating film. Ceramic coatings having such a configuration can minimize surface damage even after prolonged exposure to plasma.

Coating, Plasma, Ceramic Coating Film

Description

Ceramic coating having plasma resistance {Plasma-Resistant Ceramic Coated Substrate}

The present invention relates to a ceramic coating, and more particularly, to a plasma resistant ceramic coating including a ceramic coating film having pores of 1% or less.

In general, in a plasma processing apparatus used in a semiconductor manufacturing process, a gas such as fluoride, chloride, or bromide may be converted into a plasma inside a chamber of the plasma processing apparatus, and the object to be processed may be processed using the plasma-formed gas. In such a plasma processing apparatus, as well as the processing of the object to be processed, the inner surface of the chamber or the internal component material of the plasma processing apparatus may be corroded by the gases.

In order to prevent corrosion of the inner surface of the chamber or the material of the internal parts, a ceramic coating film containing an oxide such as yttrium oxide (Y 2 O 3) or aluminum oxide (Al 2 O 3) may be sprayed on the inner surface of the chamber or the surface of the internal material. It can be formed by a coating method. However, the ceramic coating film formed by the thermal spray coating method contains high pores of 5% or more due to the non-uniform coating due to the difference in melting time or incomplete melting due to the characteristics of the ceramic material of high melting point. These pores not only make the corrosion easily occur when the plasma or various reactive gases applied to the semiconductor manufacturing process come into contact with the coating film, but also the ceramic coating film damaged by the corrosion acts as a source of contaminants inside the device, resulting in wafer It may cause contamination.

Accordingly, some methods have been proposed to reduce the porosity of the ceramic coating film to increase the density of the coating film and thereby improve plasma resistance. For example, in order to easily melt a high melting point ceramic and obtain a uniform coating film, a method of spray coating a ceramic powder of several tens to hundreds of nanometers instead of a conventional tens of micrometers powder, and an organic solvent treatment or a thermal spray coating Methods have been proposed to remove unmelted particles and reduce pores through heat treatment. However, such a method is not a replacement of the spray coating itself, but only for the improvement of the use powder or the post-treatment process of the coating film. The problem is that the cost is increased.

Accordingly, it is an object of the present invention to provide a ceramic coating including a ceramic coating film having excellent porosity characteristics while having pores of 1% or less without applying a spray coating method.

The ceramic coating for realizing the above object of the present invention has an etching rate of 13 to 25nm / min with respect to the plasma to be coated on the surface of the coating and the coating to be applied to the plasma apparatus and formed at 800W power, the pores It has a structure containing the ceramic coating film whose content rate is 0.1 to 1%. Plasma-resistant ceramic coatings having such a structure include relatively low surface roughness, high adhesion, and less than 1% of pores compared to ceramic coatings obtained by conventional thermal spray coating methods, and thus are exposed to plasma for a long time. Damage to that surface can be minimized.

As an example, the ceramic coating layer may be formed by performing the following steps (A) to (D). Step (A) is a step of crushing, crushing and dispersing the ceramic powder into a ceramic powder having a particle size of 0.1 to 1.0um. In the step (B), the dispersed ceramic powder is jetted to the surface of the coated object at a speed of 250 to 400 m / s to impinge on and crush. Step (C) is a step of adsorbing the crushed ceramic particles to the surface of the coating. Step (D) is a step of forming a ceramic coating film by repeatedly performing the steps (A) to (C) at least twice to accumulate and fix the crushed ceramic particles on the surface of the coating. As an example of said ceramic coating film, a yttrium oxide film, an aluminum oxide film, or these mixed films etc. are mentioned. In addition, the ceramic powder is subjected to a crushing process to have a polygonal shape whose surface includes curvature or grooves. The crushed ceramic particles have a particle size of 80 to 200nm.

The coated object of the plasma apparatus includes aluminum, stainless steel, quartz or ceramic material. In addition, examples of the coating target include gas distribution plates, static chucks, shower heads, inner walls of chambers, cylinders, focus rings, and the like.

The ceramic coating having the characteristics described above includes a ceramic coating film having pores of several to several tens of times or less than the ceramic coating film formed by performing a conventional spray coating process. For this reason, the ceramic coating has plasma resistance and chemical resistance characteristics that minimize damage even when exposed to plasma for a long time. Accordingly, when the plasma coating ceramic coating is applied as a component of the plasma apparatus, not only can significantly reduce the maintenance cost of the plasma processing apparatus but also contaminate the wafer due to the generation of contaminants such as particles and the adsorption of contaminants on the ceramic coating layer. Can be minimized.

Hereinafter, a ceramic coating according to various aspects of the present disclosure will be described with reference to the accompanying drawings. The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, parts, or combinations thereof. Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not. However, the present invention is not limited to the following embodiments, and those skilled in the art may implement the present invention in various other forms without departing from the technical spirit of the present invention.

ceramic Coating

1 is a cross-sectional view showing a ceramic coating having a plasma resistance according to an embodiment of the present invention, Figure 2 is an electron micrograph showing a cross section of the ceramic coating film contained in the ceramic coating shown in FIG.

Referring to FIGS. 1 and 2, the ceramic coating body 30 of the present embodiment includes a coating body 10 applied to a plasma apparatus and a ceramic coating film 20 deposited on the coating body. Specifically, the target body 10 includes aluminum, quartz, aluminum oxide, or anodizing materials, and is a component applied to the inside of the plasma apparatus. Examples of the coated object 10 include a gas distribution plate, an electrostatic chuck, a shower head, an inner wall of a chamber, a cylinder, a focus ring, and the like.

The ceramic coating film 20 is formed to a predetermined thickness on the to-be-coated body 10 by room temperature fine particle deposition method, has an adhesion of 75 to 95Mpa with the to-be-coated object 10, and has a thickness of about 0.1 to 3um. It is a metal oxide film having surface roughness and having plasma resistance within 0.1 to 1% of pores. Examples of the metal oxide film include yttrium oxide (Y ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), and the like. In addition, the ceramic coating layer preferably has an etching rate of about 13 to 25nm / min when exposed to the plasma formed at 800W power. This is because, when the etch rate of the ceramic coating film exceeds 25nm / min, the problem that the maintenance cost of the plasma apparatus is increased.

When the content of pores contained in the ceramic coating film 20 exceeds 1%, a problem occurs that the surface damage is greater than that of the ceramic coating film containing 1% pores. Here, the damaged part of the surface of the ceramic coating film 20 acts as a cause of particle generation that contaminates the wafer. Therefore, the ceramic coating film 20 of the present invention preferably contains less than 1% pores.

In addition, when the surface roughness of the ceramic coating film 20 is less than 0.1, the plasma resistance is slightly improved, but the by-products caused by the gas in the chamber are less attached to the surface, resulting in increased contamination of the wafer. On the other hand, if the surface roughness exceeds 3um, the process by-products are easily attached on the surface of the ceramic coating layer, but the ceramic coating layer is quickly corroded. Therefore, the ceramic coating film has a surface roughness in the range of 0.1 to 3um and preferably has a surface roughness in the range of 0.5 to 1um. Also,

Figure 3 is a process flow diagram showing a method of forming a ceramic coating according to an embodiment of the present invention.

Referring to FIG. 3, in order to form the ceramic coating body according to the exemplary embodiment of the present invention, first, the ceramic powder accommodated in the ceramic powder supply unit of the ceramic coating apparatus is prepared (step S110).

The ceramic powder is a ceramic powder applied to a conventional spray coating process, and includes yttrium oxide (Y ₂ O ₃ ) powder, aluminum oxide (Al ₂ O ₃ ) powder, or a mixture thereof, and the like, and has a thickness of about 0.1 to 1.0 μm. Has a particle size. When the particle size of the ceramic powder applied to the ceramic coating film forming process is less than 0.1um, the cohesion between the ceramic powders increases, so that the powder supply is not properly performed. On the other hand, if the particle size exceeds 1.0 μm, the acceleration force is increased due to the increase in the weight of the ceramic powder itself during coating, which causes a problem that the particles bounce off the surface of the coated body of the ceramic coating after fracture. Therefore, in the present embodiment, the ceramic powder may have a particle size of 0.1 to 1.0 μm, and preferably may have a particle size of 0.4 to 0.8 μm.

As one example, the ceramic powder may be formed by performing a ball mill process on preliminary ceramic particles having a particle diameter of 2 to 10um. As another example, the ceramic powder may be formed by performing a plasma cooling grinding method. The plasma cooling pulverization method includes the step of cold pulverization under nitrogen gas after plasma melting of the pre-ceramic particles having a particle diameter of about 2 to 10um.

In particular, in the present embodiment, it is preferable that the existing ceramic powder is manufactured by a mechanical crushing process so that the surface of the ceramic powder is not spherical but has a polygonal shape including a bend or a groove. The mechanical crushing process may include a ball mill process and a plasma low temperature crushing process, and the like, and do not limit the present invention. This is because the ceramic powder having such a polygonal shape may be crushed to have a particle size of easier and smaller size when collided and crushed on the surface of the coated object 10. The coated object includes aluminum, quartz, aluminum oxide or anodizing materials and is a component applied inside the plasma apparatus. The coated body is seated inside a chamber of the coating apparatus.

Subsequently, the ceramic powder having the aggregated state is dispersed into the ceramic powder having a particle size of 0.1 to 1.0 um (step S120).

Since the aggregated ceramic powder has a particle size of about 2 to 10um substantially, the ceramic powder must be dispersed to have a particle size of 0.1 to 1.0um again. For example, the dispersion of the ceramic powder may be caused by a collision / crushing reaction in the aggregated ceramic powder provided from the ceramic powder supply unit at a high speed into the dispersion unit included in the coating film forming apparatus together with the carrier gas. It can be done by generating continuously. Examples of the carrier gas include oxygen gas, argon gas (Ar), nitrogen gas (N ₂ ), hydrogen gas (H ₂ ), helium gas (He), and the like. These can be used individually or in mixture of 2 or more.

Subsequently, the dispersed ceramic powder is jetted at high speed to the surface of the coated object to crash / crush (step S130).

The ceramic powder dispersed in the carrier gas is ejected at high speed to the surface to be coated by the ejecting unit. The dispersed ceramic powder is ejected together with the carrier gas at a speed of about 250 to 400 m / s. Specifically, the ejection rate of the ceramic powder may vary depending on the pressure inside the gas providing unit providing the carrier gas and the pressure inside the chamber in which the ceramic coating film is formed. In this embodiment, the inside of the chamber is about vacuum (10 ^-2 torr), and the pressure inside the dispersion unit and the chamber must be maintained in a vacuum state, and the ejection is performed by supplying a gas having an internal pressure and a flow rate of the chamber thus formed. By passing through the unit, the injection speed can be accelerated to subsonic or supersonic (about 250 to 400 m / s) regions.

In particular, when the speed of the dispersed ceramic powder sprayed to the surface of the coating is less than 250m / s, not only the fracture of the dispersed ceramic powder is easy, but also the problem that the formation rate of the ceramic coating film is reduced. When the spraying speed exceeds 400 m / s, the dispersed ceramic powder is easily broken, but has a high kinetic energy after the shredding, so that it is not adsorbed to the coated body and is thrown out, or the coating layer or the coating layer is torn off. do. Therefore, the dispersed ceramic powder is preferably ejected at a speed of about 250 to 400 m / s, more preferably at a speed of about 300 to 350 m / s.

The dispersed ceramic powders ejected under the conditions described above are crushed (split) by colliding with the surface of the coating to be formed into crushed ceramic particles having a nanoparticle size. When the size of the crushed ceramic particles is less than 80nm, it becomes less than the limit mass of the ceramic particles, so that sufficient impact force is not generated, so that the cumulative speed of the crushed ceramic particles adsorbed (deposited) on the surface of the coated body is significantly reduced. Is generated. On the other hand, when the size of the crushed ceramic particles exceeds 200nm, the cumulative rate of the crushed ceramic particles adsorbed on the surface of the coating is increased than when using particles smaller than 80nm, but the particles are not adsorbed when the ceramic coating film is formed. An increase in the amount of hinders the formation of the coating layer, and also increases the pore content. Therefore, the crushed ceramic particles preferably have a size of about 80 to 200 nm, preferably a size of about 100 to 150 nm.

In general, the surface of the coated object preferably has a roughness of 20 μm or less. When the coating layer is formed by applying particles having a size of about 80 to 200 nm to form the coating layer, when the roughness of the coated body is 20 μm or less, most of the grooves of the coated body are filled to make the surface of the coating layer with an roughness of 0.1 to 3 μm. Although it may be formed, when the roughness of the coated object is more than 20um, the surface of the coated surface is filled and there is a limitation in forming the coating layer, thereby causing a problem in that the coating layer is formed along the surface roughness of the coated layer.

However, since the ceramic coating film forming method of the present embodiment is less affected by the surface roughness of the coating layer than the thermal spray coating method, a separate process for making the surface of the coating layer have a smooth surface is not required.

As an example, in the case of forming a yttrium oxide film, which is a ceramic coating film of the present invention, the yttrium oxide powder is ejected from the spray gun at a speed of about 300 to 350 m / s, and the spray gun is about 40 to 60 m / min on the coating body. Preferably at a distance of about 100 to 130 mm between the spray gun and the surface of the coated object, the spray gun spraying the coating material on the surface of the coated object at an angle of about 80 to 90 degrees. Do.

The crushed ceramic particles are adsorbed (deposited) on the surface to be coated (step S140).

Adsorption of the ceramic particles crushed in the step S140 is made by the kinetic energy of the ceramic particles formed by colliding with the surface of the coating. That is, since the ceramic particles collide with the surface of the coating to be broken and formed into pieces, and have a constant kinetic energy at the same time, the ceramic particles are inserted (embedded) into the surface of the coating to be adsorbed. At this time, the ejected ceramic particles are crushed to insert a part into the coating to form a thin coating layer, and a part of the ceramic powder is inserted into the coating layer by the ceramic particles ejected onto the ceramic coating layer formed on the coating layer to form a coating layer. do. In the method of forming a ceramic coating according to the present embodiment, the ceramic coating film is formed through a continuous process in which the ejected ceramic powder is partially inserted by crushing particles on the coating layer or the coated coating layer.

Subsequently, cumulative adsorption of the crushed ceramic particles on the surface of the coating body forms a ceramic coating including a ceramic coating film having a porosity of 1% or less (step S150).

Specifically, the dispersed ceramic powder is spun at high speed on the surface of the coating to be collided / crushed, and the step S140 of adsorbing the fractured ceramic particles on the surface of the coating is repeated at least twice. Accordingly, the ceramic particles formed by crushing ceramic particles are accumulated and adsorbed on the surface of the coating to include a ceramic coating film having a pore content of 1% or less. Here, the repeating of the steps S130 and S140 is performed by the ejection unit for ejecting the ceramic powder with the carrier gas at a speed of about 250 to 400m / s performs a reciprocating motion in a width larger than the diameter of the coating body Can be. Here, the ejection unit reciprocates in a width larger than the diameter of the coating body in order to uniformly form the coating layer on the outer peripheral portion and the inner peripheral portion of the coating body. In addition, the reciprocating motion can adjust the thickness of the ceramic coating film contained in the ceramic coating body at the number of times.

Since the ceramic coating formed by the above-mentioned room temperature fine particle deposition method includes a ceramic coating film having a pore content of 1% or less, unlike the ceramic coating film formed by the spray coating method, the plasma coating has excellent plasma resistance and is about 13 to about plasma formed at 800W power. To an etching rate of from 25 nm / min. In addition, the surface of the ceramic coating formed has a roughness of about 0.1 to 3um.

When the surface roughness of the ceramic coating is less than 0.1, the plasma resistance is slightly improved, but the by-products caused by the gas in the chamber are less likely to adhere to the coating surface, resulting in increased contamination of the wafer. On the other hand, when the surface roughness exceeds 3um, the process by-products are easily attached to the surface of the ceramic coating, but the ceramic coating is quickly corroded. Therefore, the ceramic coating is formed to have a surface roughness in the range of 0.1 to 3um and preferably to have a surface roughness in the range of 0.5 to 1um.

ceramic Coating  Characteristic evaluation 1

The thickness of the ceramic coating films of the ceramic coating body formed according to the coating method and coating conditions disclosed in Table 1 was measured. Here, the coating method of the comparative example is a well-known atmospheric plasma spray (APS) coating method, the coating method of the implementation is a room temperature particulate deposition method comprising the step S110 to 150. In particular, the conditions of the coating methods of the present embodiments eject the yttrium powder from the spray gun at a speed of about 330 m / s, the spray gun is transported across the coating at a speed of about 1 mm / sec, and the spray gun And a distance of about 110 mm between the surface of the coated object 10 and the spray gun set the spray angle of the coating material on the surface of the coated object about 90 degrees. The coating is a gas distribution plate, the ceramic coating is a gas distribution plate having a yttrium film formed thereon, and the size of the particles indicates the size of the particles when ejected from the spray gun.

TABLE 1

As described in Table 1, in Examples 1 to 7, it was confirmed that the coating thickness of the yttrium oxide film formed when the particle size was 700 to 800 nm showed the optimal thickness. In addition, it was confirmed that when the sizes of the particles are similar to each other, the coating thickness is increased when the yttrium particles have a polygonal shape as shown in FIG. 5 rather than a spherical shape as shown in FIG. 4. Accordingly, when forming a ceramic coating having a yttrium oxide film formed on the surface of the coating, it is most preferable to use a ceramic powder having a polygonal particle size of 700 to 800 nm.

ceramic Coating  Characteristic evaluation 2

After forming the ceramic coating body according to the coating method and coating conditions disclosed in Evaluation 1, the pore content and plasma resistance of the ceramic coating body were evaluated. The results are shown in Table 2 below. Here, the plasma characteristic evaluation was performed in an AMAT P-500 plasma chamber by setting fluorocarbon gas (CF4) 50 sccm, oxygen gas 10 sccm, chamber pressure 0.05 torr, plasma power 800 W, and plasma exposure time 60 minutes. The coating is a gas distribution plate, and the ceramic coating is a gas distribution plate on which a yttrium oxide film is formed.

TABLE 2

Referring to Table 2, the yttrium oxide film of the ceramic coating formed by the method of Example has a relatively high plasma resistance by having a pore content of 1% or less. On the other hand, the yttrium oxide film of the ceramic coating formed by the method of Comparative Example 1 has a pore content of 5% or more, so that the plasma characteristics are relatively very low, so that the corrosion occurs quickly.

Specifically, it was confirmed that the yttrium oxide film (Example 1) of the ceramic coating disclosed in FIG. 6 was significantly smaller in pore content than the yttrium oxide film (comparative example 1) of the ceramic coating disclosed in FIG. 7. In addition, the yttrium oxide film (Example 1) of the coating body exposed to the plasma of FIG. 8 has a relatively high surface loss due to plasma compared to the yttrium oxide film (Comparative Example 1) of the ceramic coating body exposed to the plasma of FIG. 9. Very small was confirmed.

The ceramic coating having the characteristics described above includes a ceramic coating film having pores of several to several tens of times or less than the ceramic coating film formed by performing a conventional spray coating process. For this reason, the ceramic coating has plasma resistance and chemical resistance characteristics that minimize damage even when exposed to plasma for a long time. Accordingly, when the ceramic coating having plasma resistance is applied as a component of the plasma apparatus, the maintenance cost of the plasma processing apparatus may be significantly reduced, and the contamination of the wafer due to particle generation may be minimized.

1 is a cross-sectional view showing a ceramic coating having plasma resistance according to an embodiment of the present invention.

FIG. 2 is an electron micrograph showing a cross section of a ceramic coating film included in the ceramic coating shown in FIG. 1.

Figure 3 is a process flow diagram showing a method of forming a ceramic coating according to an embodiment of the present invention.

Figure 4 is a photograph showing the ceramic particles applied when the ceramic coating body of Example 2 formed.

5 is a photograph showing ceramic particles applied when the ceramic coating body of Example 5 was formed.

6 is a photograph showing a cross section of the ceramic coating body of Example 1. FIG.

7 is a photograph showing a cross section of the ceramic coating body of Comparative Example 1. FIG.

8 is a photograph showing the surface of the ceramic coating of Example 1 exposed to plasma.

9 is a photograph showing the surface of the ceramic coating of Comparative Example 1 exposed to plasma.

<Explanation of symbols for the main parts of the drawings>

10: coating object 20: ceramic coating film

30: ceramic coating

Claims (7)

A coated body applied to the plasma apparatus; And Plasma resistant ceramic coating comprising a ceramic coating film formed on the surface of the coating material and having an etching rate of 13 to 25 nm / min with respect to the plasma formed at 800W power, the content of pores is 0.1 to 1%. The method of claim 1, wherein the coated body comprises aluminum, stainless steel, quartz or ceramic material, and is any one selected from the group consisting of a gas distribution plate, a static chuck, a showerhead, an inner wall of a chamber, a cylinder, and a focus ring. Plasma resistant ceramic coating body made of. The ceramic coating of claim 1, wherein the ceramic coating film comprises a yttrium oxide film or an aluminum oxide film. The method of claim 1, wherein the ceramic coating film (A) dispersing the ceramic powder into a ceramic powder having a particle size of 0.1 to 1.0um; (B) ejecting the dispersed ceramic powder onto the surface of the coated object at a speed of 250 to 400 m / s to impinge on and crush it; (C) adsorbing partially broken ceramic particles impinged on the coating to the surface of the coating; And (D) performing step (A), step (B) and step (C) repeatedly at least two times in succession to accumulate and adsorb cumulatively adsorbed ceramic particles formed on the surface of the coating body. Plasma resistant ceramic coating, characterized in that. The method of claim 4, wherein the ceramic powder is subjected to a mechanical crushing process including a crushing by a mechanical ball mill process or plasma low temperature crushing process is characterized in that the surface has a polygonal shape including a bent or groove Plasma resistant ceramic coating body made of. The plasma-resistant ceramic coating of claim 4, wherein the crushed ceramic particles have a particle size of 80 to 200 nm. According to claim 1, wherein the ceramic coating film has a surface roughness of 0.1 to 3um, plasma-resistant ceramic coating, characterized in that having an adhesion of 75 to 95Mpa with the coated object.

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