KR102382082B1 - Method for manufacturing Anodized Coating Layer on Aluminium Member and Aluminium Member for Semiconductor Manufaturing Device by the Same - Google Patents

Abstract

The present invention relates to a method for forming an anodized film on a surface of an aluminum or aluminum alloy member and an aluminum or aluminum alloy member having an anodized film produced by the method. By anodizing an aluminum or aluminum alloy member in an electrolyte solution with high solvent resistance, the method can form an alumina film having a uniform thickness of tens to hundreds of nanometers. An anodic oxidation treatment may be performed in an electrolyte solution containing sulfuric acid at a concentration of 0.01 to 0.5%.

Description

A method for forming an oxide film on an aluminum-containing member, and an aluminum-containing member for a semiconductor manufacturing apparatus formed thereby, TECHNICAL FIELD

The present invention relates to a method for forming an anodized film on the surface of an aluminum or aluminum alloy member, and to an aluminum or aluminum alloy member having an anodized film formed by the method, and more particularly, an anodized alumina film having excellent plasma resistance It relates to a member for a device for manufacturing a coated semiconductor or display.

Some fabrication processes in the semiconductor industry, such as plasma etching and plasma cleaning processes, expose a substrate to a high velocity plasma stream to etch or clean the substrate. Plasma can be very erodive and can erode processing chambers and other surfaces exposed to the plasma. This erosion can generate particles, which often contaminate the substrate being processed, causing device defects.

For example, in the case of a plasma etching apparatus, a chlorinated gas such as carbon tetrachloride or boron chloride or a fluorine-based gas such as fluorocarbon, nitrogen fluoride, or fluorosulfuric acid is used as the etching gas as the etching gas. Accordingly, plasma resistance is required for components such as the inner wall surface of the etching chamber exposed to plasma in a corrosive gas atmosphere.

In addition, in the CVD process, when silicon dioxide (SiO ₂ ) is deposited on a wafer disposed in a process chamber, silicon dioxide is deposited not only on the wafer but also on the surface of the component inside the process chamber. Accordingly, in order to perform a continuous CVD process, a cleaning process of removing the silicon dioxide deposited on the surface of the process chamber component after the deposition process should be performed.

In the cleaning process to remove the silicon dioxide deposited on the surface of the process chamber parts, a cleaning gas such as ClF ₃ , NF ₃ plasma is used. , there is a problem in that aluminum fluoride (AlF ₃ ) particles are generated on the surface of the process chamber component.

Therefore, since the aluminum fluoride (AlF ₃ ) particles accumulate on the wafer or stick to the process parts, the continuous CVD process cannot be performed, so the production yield is reduced, and the process chamber parts are continuously cleaned externally by plasma treatment (ex-situ cleaning) was required.

Therefore, in order to solve these problems, attempts have been made by researchers around the world to coat a ceramic on the surface of a metal material having excellent mechanical strength in various ways. Among them, a plasma spray coating method is currently the most widely known method. Plasma spray coating is to form a coating layer by spraying ceramic powder on the surface of an object to be coated together with a gas for forming plasma. At this time, the temperature of the plasma gas reaches a high temperature of 20,000° C. and instantaneously melts the ceramic powder. When the molten particles adhere to the object to be coated, a coating layer is formed through a solidification process.

However, in this high-temperature process, the object to be coated is also exposed to high temperature, a large residual stress exists at the interface between the coating layer and the object to be coated after cooling, and expensive equipment for coating and expensive raw material powder must be used. In particular, when the workpiece is a metal material, there is a problem in that the metal is oxidized when exposed to high temperature, so plasma spray coating must be performed in a vacuum, which requires more expensive equipment. Therefore, many researchers have made various attempts to coat the surface of a metal material with a ceramic in various ways, but it is not easy to perform a dense ceramic coating without cracks and defects.

In addition, there are cases where chemical vapor deposition, physical vapor deposition, or sputtering, which are generally used in the past, are applied, but in this case, it is a thin film manufacturing process. There is a problem in that economical efficiency is lowered, such as taking, and there is a problem in that it is difficult to obtain a strong bonding force between the substrate and the coating layer.

On the other hand, in general, by coating various oxide films on the surface of an aluminum member through methods such as anodization treatment, electroplating, vapor phase growth method, plasma electrolytic oxidation method, etc., it is possible to manufacture a plasma-resistant member with excellent mechanical, electrical and chemical properties. .

In particular, as a method for forming an oxide film using anodization treatment, a method of controlling the electrolyte solution at a low temperature when forming the anodization film and a method of performing electrolysis at a high current density are employed. Formation of the anodic oxide film increases the crack generation of the anodized film, and there is also a problem that high energy is required for these methods.

Next, the prior art existing in the field to which the technology of the present invention pertains will be briefly described, and then, technical matters to be differentiated by the present invention will be described.

First, Korean Patent Application Laid-Open No. 10-2015-0081013 discloses: i) forming a barrier layer with a valve metal on the surface of a metal interior and exterior material; ii) forming a surface layer of an aluminum (Al)-based metal on the barrier layer; iii) anodizing the surface on which the surface layer is formed; and iv) coloring a dye on the anodized surface and sealing the surface of the metal interior and exterior material comprising the steps of (Patent Document 0001).

In addition, Korea Patent No. 10-1207708 discloses an anodization method of aluminum in which an object made of an aluminum alloy is anodized in an electrolyte to form an anodized film on the surface of the object, wherein two or more carboxyl groups are formed in the electrolyte. containing at least two acids selected from organic acids having , wherein the aluminum alloy contains 9.6 to 12.0% by weight of silica, the electrolyte moves at least on the outer surface side of the object to be treated at an average speed of 15 cm/sec or less, and the surface temperature of the object to be treated is 80° C. or less, and A method of anodizing aluminum in which the anodization is performed under the condition that the current density is in the range of 10 to 170 A/dm ² is disclosed (Patent Document 0002).

However, the oxide film-coated aluminum member disclosed in the prior literature has a problem in that it cannot be stably used for a long period of time in various plasma-resistant members due to poor corrosion resistance, hardness, chemical resistance, abrasion resistance, mechanical properties and electrical properties. In addition, since the adhesive force between the aluminum substrate and the coating layer is low, the coating layer may peel off during use, resulting in process failure.

The inventor felt limitations in the method for producing such a plasma-resistant coating film, and repeated studies on a method for producing a uniform anodized thin film while optimizing the bonding force between the coating layers, resulting in the present invention.

Korean Patent Publication No. 10-2015-0081013 Korean Patent Registration No. 10-1207708

The main object of the present invention is to solve the above problems, and by anodizing the aluminum member in an electrolyte solution having high solvent resistance, an alumina film of tens to hundreds of nanometers is uniformly formed on the aluminum member. An object of the present invention is to provide a method for producing an alumina film to be formed.

In order to achieve the above object, in one embodiment of the present invention, an alumina film is formed by anodizing the surface of an aluminum member, and the anodizing treatment is 10 ⁵ to 10 ⁷ It provides a method of forming an oxide film of a member containing aluminum in a semiconductor or display manufacturing apparatus, characterized in that it is performed in an electrolyte solution having a solvent resistance of Ω m.

In a preferred embodiment of the present invention, the anodization treatment may be performed in an electrolyte solution containing sulfuric acid at a concentration of 0.01 to 0.5%.

In a preferred embodiment of the present invention, the anodization may be performed at a voltage of 10 to 40V for 20 to 60 minutes.

In a preferred embodiment of the present invention, the temperature of the electrolyte solution may be in the range of 0 °C to 35 °C.

In a preferred embodiment of the present invention, the alumina film may have a thickness of 10 to 500 nm.

In a preferred embodiment of the present invention, the standard deviation of the thickness of the alumina film may be less than 5% of the average thickness.

In a preferred embodiment of the present invention, the alumina film has a thickness of 150 to 500 nm, and the standard deviation of the alumina film thickness may be less than 2% of the average thickness.

In another preferred embodiment of the present invention, the present invention provides an aluminum-containing member of a semiconductor or display manufacturing apparatus manufactured by the method described above.

In another preferred embodiment of the present invention, the present invention provides a plasma-resistant shower head produced by the method described above.

The alumina film produced by the method for forming an oxide film on an aluminum member according to the present invention can uniformly form an alumina film of several tens to hundreds of nanometers on the entire surface of the aluminum member.

In addition, the alumina film formed at a low current density has a low cracking rate and improved adhesion to the aluminum member, thereby suppressing the formation of particles due to partial detachment from the aluminum member during the plasma etching or plasma cleaning process.

In addition, when the aluminum-containing member manufactured according to the present invention is formed in a shower head used in a CVD process, it is possible to prevent a process issue in which a hole size is reduced.

1 is a schematic view of (a) an alumina film according to the present invention and (b) an exemplary position at which the thickness of the alumina film is measured in order to obtain a thickness deviation of the alumina film coated on the shower head.
2 is a scanning electron microscope (SEM) photograph of the alumina coating according to (a) Example 1 (b) Example 2 according to the present invention.
3 is a scanning electron microscope (SEM) photograph of the alumina film according to Example 3 according to the present invention.
4 is a scanning electron microscope (SEM) photograph of the alumina film according to Example 4 according to the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is those well known and commonly used in the art.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

In the method for forming an oxide film of a member containing aluminum in a semiconductor or display manufacturing apparatus according to the present invention, an alumina film is formed by performing anodizing on the surface of the aluminum member, wherein the anodizing treatment is 10 It is characterized in that it is carried out in an electrolyte solution having a solvent resistance of ⁵ to 10 ⁷ Ω m.

The equipment for the anodization treatment includes an electrochemical bath, an anode to which a positive voltage is applied and an alumina film (Al ₂ O ₃ ) is formed, and a cathode to which a negative voltage is applied to supply electrons to the aluminum cations; , and an electrolyte solution contained in the electrolytic cell, and a power supply for supplying voltage to the anode and the cathode. The positive electrode and the negative electrode are spaced apart from each other by a predetermined distance. A member made of aluminum or an aluminum alloy is used as the anode.

Looking at the anodization process, water molecules (H ₂ O) in the electrolyte solution are electrolyzed into hydrogen ions (H ⁺ ) and hydroxyl ions (OH ⁻ ). Hydrogen ions (H ⁺ ) move toward the cathode, combine with electrons between the electrolyte solution and the cathode surface, and are released as hydrogen gas (H ₂ ).

On the other hand, the aluminum metal element on the surface of the aluminum member, which is the anode, which is in contact with the electrolyte solution, forms a film of alumina (alumina, Al ₂ O ₃ ) component according to the chemical reaction described in the following Reaction Formulas (1) to (3).

Al → Al ³⁺ + 3e ^- (1)

Al ³⁺ + 3H ₂ O → Al(OH) ₃ + 3H ⁺ (2)

2Al(OH) ₃ → Al ₂ O ₃ + 3H ₂ O (3)

That is, the electrolyte solution facilitates the movement of charged electrons or ions to form an alumina film on the surface of a member made of aluminum or an aluminum alloy.

At this time, the anodization treatment can control the amount of chemical reaction in the anode, which is an alumina member, by changing the resistance of the electrolyte solution, and accordingly, the growth rate of the alumina (aluminum oxide) film produced by the anodization reaction and the quality of the alumina film can be controlled.

Specifically, the anodization treatment is performed in an electrolyte solution having a high solvent resistance of 10 ⁵ to 10 ⁷ Ω·m, thereby forming a low current density. This is low, the adhesion to the aluminum member is improved, and the shape detached from the aluminum member during the plasma etching or plasma cleaning process is suppressed.

In this case, in order to prepare an electrolyte solution having a high solvent resistance in the anodization treatment, it may be prepared by including sulfuric acid at a concentration of 0.01 to 0.5% in distilled water.

Here, in order to keep the solvent resistance or acid concentration of the electrolyte solution near the surface of the aluminum-containing member constant according to the reaction time during the anodization reaction, it is preferable to mechanically mix the electrolyte solution in the electrolytic cell.

The anodization may be performed in a direct current, alternating current, or direct/AC superposition method.

The anodizing treatment is preferably performed for 20 to 60 minutes at a voltage of 10 to 40V. If the voltage is less than 10 V, the growth rate of the alumina film is too slow, which is inefficient in terms of productivity. It is difficult to form an alumina film.

Although the temperature of the electrolyte solution is not particularly limited, it is preferable to maintain the temperature of the electrolyte solution at 0 to 35° C. for the preparation of an alumina film having excellent chemical, mechanical and electrical properties. When the temperature does not reach 0 ° C, the growth rate of the alumina film is too slow and inefficient. When the temperature exceeds 35 ° C, the growth rate of the alumina film increases, but the surface roughness of the alumina film increases significantly, resulting in a uniform alumina film difficult to form

At this time, a magnetic stirrer and a stirring magnetic bar are provided in the electrolytic cell to prevent the temperature rise due to exothermic reaction during the anodization process and to increase the uniformity of the electrochemical reaction over the entire aluminum metal surface. Thus, the electrolyte solution may be stirred, and a cooling device or a temperature control device may be installed to maintain a constant temperature of the electrolyte solution in the electrolyzer.

At this time, as the voltage of the anodization process increases, it is advantageous to stably grow the alumina film to set the temperature of the electrolyte solution to a relatively low temperature.

In addition, the oxide film forming method according to the present invention can uniformly form a thin alumina film with a thickness of 10 to 500 nm on the surface of an aluminum or aluminum alloy member by anodizing in an electrolyte solution having a high solvent resistance value. .

In this case, the standard deviation value of the thickness of the alumina film formed on the surface of the aluminum or aluminum alloy member may be less than 5% of the average thickness of the alumina film.

In addition, when the alumina film formed on the surface of the aluminum or aluminum alloy member has a thickness in the range of 150 to 500 nm, the standard deviation value of the alumina film thickness may be less than 2% of the average thickness of the alumina film.

In addition, the present invention provides a member containing aluminum of the semiconductor or display manufacturing apparatus manufactured by the above oxide film forming method.

In this case, the components of the CVD process chamber in the semiconductor manufacturing apparatus include a heater, a shower head, a susceptor, an inner wall of the process chamber, a baffle, an electrode, and a power terminal. ), a flange, a screw, a bar, a heater support, a bracket, and the like.

In particular, in the showerhead surface-treated by the alumina film forming method according to the present invention, a uniform and thin alumina film is formed on the inner surface of the hole to improve corrosion resistance and plasma resistance. there is.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples only illustrate the present invention, and the present invention is not limited by the following examples.

Examples 1-3

Using an aluminum substrate as an anode and a stainless substrate as a cathode, sulfuric acid (H ₂ SO ₄ , 40%) was mixed with distilled water to show the solvent resistance values in Table 1 below. Anodizing was performed in this way to prepare an aluminum substrate coated with an alumina film, and the results are shown in Table 2.

Example 4

Using an aluminum member showerhead as an anode, and a stainless steel substrate as a cathode, sulfuric acid (H ₂ SO ₄ , 40%) was mixed with distilled water to show the solvent resistance values in Table 1 above. An aluminum substrate coated with an alumina film was prepared by performing anodization in the /AC superposition method, and the results are shown in Table 2.

division solvent resistance applied voltage solvent temperature process time Example 1 1 X 10 ⁶ Ω m From 16V to 30V
(2V step) < 10℃ 1600s Example 2 1 X 10 ⁶ Ω m From 16V to 30V
(2V step) < 10℃ 1600s Example 3 3 X 10 ⁵ Ω·m From 16V to 30V
(2V step) < 10℃ 1600s Example 4 6 X 10 ⁵ Ω·m From 16V to 30V
(2V step) < 10℃ 1600s

division Example
One Example
2 Example
3 Example
4 Hole inside *zone 1 (nm) 41 35 338 179 *zone 2 (nm) 40 34 331 184 *zone 3 (nm) 38 33 329 181 *Surface (nm) 40 34 330 185 Coating layer thickness average value (nm) 39.7 34 332 182.2 Standard Deviation 1.1 0.7 3.5 2.4

*Zone 1, zone 2, zone 3, and the measurement positions of the surface are shown as examples of each position in the shower head in Fig. 1(b) below.

Comparative Examples 1 to 8

Using an aluminum substrate as an anode and a stainless steel substrate as a cathode, sulfuric acid (H ₂ SO ₄ , 40%) was mixed with distilled water to show the solvent resistance values in Table 3 below. Anodizing was performed in this way to prepare an aluminum substrate coated with an alumina film, and the results are shown in Table 4.

division solvent resistance applied voltage solvent temperature process time Comparative Example 1 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 900 s Comparative Example 2 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 600 s Comparative Example 3 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 600 s Comparative Example 4 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 1200 s Comparative Example 5 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 800 s Comparative Example 6 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 1600s Comparative Example 7 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 1400 s Comparative Example 8 1 X 10 ³ Ω m From 20 V to 50 V
(2V step) < 0℃ 1000 s

division comparative example
One comparative example
2 comparative example
3 comparative example
4 comparative example
5 comparative example
6 comparative example
7 comparative example
8 Hole inside *zone 1 (nm) 476 245 296 710 365 1200 676 503 *zone 2 (nm) 371 254 342 713 382 924 1000 397 *zone 3 (nm) 494 300 226 593 371 842 728 516 *Surface (nm) 624 320 255 776 448 1500 733 528 Coating layer thickness average value (nm) 491 279 279 698 391 1116 784 486 Standard Deviation 89.9 31.2 43.7 66.1 33.2 258.1 126.5 52.1

* Zone 1, zone 2, zone 3, and the measurement positions of the surface are shown as examples of each position in the shower head in Fig. 1(b) below.

Experimental Example 1: Observation of an alumina film

2(a) is a side scanning electron microscope (SEM) photograph of the alumina film according to Example 1 according to the present invention, and FIG. 2(b) is the alumina of Example 2 prepared under the same experimental conditions as in Example 1. This is a scanning electron microscope (SEM) photograph of the side of the film, and through this, it was confirmed that a uniformly thin anodized film can be reproducibly implemented by the method for forming an oxide film according to the present invention.

In addition, the following Figure 2 is a side scanning electron microscope (SEM) photograph of the alumina film according to Example 3 according to the present invention, which is thicker by anodizing in an electrolyte solution having a solvent resistance lower than the experimental conditions in Example 1 It was confirmed that an anodized film was formed.

3 is a side scanning electron microscope (SEM) photograph in which an anodization film is formed on an aluminum member showerhead according to Example 4 according to the present invention. formation was confirmed.

As the specific parts of the present invention have been described in detail above, it will be clear to those of ordinary skill in the art that these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby. will be. Accordingly, it is intended that the substantial scope of the present invention be defined by the appended claims and their equivalents.

Claims (9)

Anodizing the surface of the aluminum member to form an alumina film,
The anodization treatment is performed in an electrolyte solution having a solvent resistance of 10 ⁵ to 10 ⁷ Ω·m,
The temperature of the electrolyte solution is 0 ℃ or more, less than 10 ℃,
The standard deviation of the thickness of the alumina film is less than 5% of the average thickness.
The method of claim 1,
The anodization treatment is a method for forming an oxide film of a member containing aluminum in a semiconductor or display manufacturing apparatus, characterized in that it is performed in an electrolyte solution containing sulfuric acid at a concentration of 0.01 to 0.5%.
The method of claim 1,
The anodizing process is a method of forming an oxide film of a member containing aluminum in a semiconductor or display manufacturing apparatus, characterized in that it is performed for 20 to 60 minutes at a voltage of 10 to 40V.
delete The method of claim 1,
The alumina film is a method for forming an oxide film of a member containing aluminum in a semiconductor or display manufacturing apparatus, characterized in that to form a thickness of 10 to 500 nm.
delete The method of claim 1,
The alumina film forms a thickness of 150 to 500 nm,
The standard deviation of the thickness of the alumina film is a method of forming an oxide film of a member containing aluminum in a semiconductor or display manufacturing apparatus, characterized in that less than 2% of the average thickness.
A member containing aluminum of a semiconductor or display manufacturing apparatus manufactured by the method according to any one of claims 1 to 7.
A plasma-resistant shower head manufactured by the method according to any one of claims 1 to 7.

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