Method for manufacturing plasma-resistant coating film

Abstract

To provide a method for manufacturing a plasma resistant coating film, excellent in bonding strength of a coating film, capable of suppressing the formation of structural defects in the coating film and capable of minimally suppressing the peeling of the coating film in a semiconductor manufacturing process or the generation of particles.SOLUTION: A method for manufacturing a plasma resistant coating film comprises the steps of: (a) forming a lower coating layer on an object to be coated using a first rare earth metal compound powder by a physical vapor phase deposition process; (b) conveying second rare earth metal compound powder; (c) injecting the conveyed second rare earth metal compound powder toward the lower coating layer formed in step (a) to form an upper coating layer. Thereby, structural defects are less, and physical properties are enhanced.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a plasma-resistant coating film, and more particularly to a method for manufacturing a plasma-resistant coating film that is applicable to a semiconductor manufacturing process including a semiconductor etching device, and the plasma-resistant coating film. [Background technology]

[0002] Next-generation semiconductors are moving in the direction of becoming lighter, thinner, shorter, and smaller, and as we enter the mobile era, ultra-fine semiconductor processes are absolutely necessary for use in electronic devices that are becoming smaller and more complex.

[0003] In particular, the etching process required for manufacturing semiconductor devices of 10 nm or less, 3D NAND flash, FinFET, MRAM, etc., is becoming increasingly difficult, and for this reason, development of technologies such as fine pattern etching is being actively pursued.

[0004] As a result, the development of etching technology for new materials and etching technology that can selectively etch only the required materials are expected to become increasingly important, and for this reason, durable semiconductor components that can withstand extreme environments are absolutely necessary for etching equipment.

[0005] That is, to suppress contamination during high-power plasma (>10Kw) processes corresponding to ultra-fine line width processes, high-density coatings are required for semiconductor components.

[0006] Generally, chambers in equipment used in semiconductor manufacturing processes are made using ceramic bulks such as anodized aluminum alloys or alumina for insulation.

[0007] Recently, chambers used in semiconductor manufacturing processes, such as deposition equipment using chemical vapor deposition (CVD) and etching equipment using plasma etching, are increasingly required to have corrosion resistance against highly corrosive gases and plasma. To achieve this high corrosion resistance, ceramic coating layers such as alumina are formed on the aluminum alloys by plasma spraying or thermal spraying.

[0008] Furthermore, since many of the semiconductor manufacturing processes performed within a chamber involve high-temperature processes such as heat treatment and chemical vapor deposition, the chamber must also be heat-resistant. Furthermore, components of semiconductor manufacturing equipment, such as chambers, must be insulating, heat-resistant, corrosion-resistant, and plasma-resistant. They must also maintain a strong bond between the coating layer and the substrate to prevent peeling of the coating layer and minimize particle generation during the manufacturing process and the resulting wafer contamination.

[0009] To this end, conventionally, commonly used methods such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and sputtering have been applied. However, these methods involve thin film manufacturing processes, which require long process times to form a thick film that satisfies the requirements for corrosion resistance, etc., resulting in poor economic efficiency. In addition, it is difficult to obtain a strong bond between the substrate and the coating layer.

[0010] On the other hand, aerosol deposition is a method in which an aerosol containing ceramic particles is sprayed from a nozzle toward a substrate, causing the particles to collide with the substrate, and using the resulting impact force to form a ceramic coating film on the substrate. Since the powder to be coated is sprayed directly, high-speed coating is possible, at around 30 μm per minute, and thickness control is possible because it is proportional to the recovery rate.

[0011] However, aerosol deposition can cause problems such as peeling over long periods of use due to the low adhesive strength formed solely through mechanical interlocking between the coating film and the surface of the base material. In addition, the coating can be etched by the CF4 plasma ions and radicals used in the dry etching process, generating particles that can contaminate the wafer.

[0012] Next, the prior art existing in the field to which the technology of the present invention belongs will be briefly described, and the technical matters that the present invention is intended to achieve in a distinctive manner will be described.

[0013] Korean Patent Publication No. 10-2013-0123821 (November 13, 2013) relates to a plasma-resistant coating film, and describes a manufacturing technology for a plasma-resistant coating film in which an amorphous first coating film is formed by plasma spray coating a thermal spray coating powder containing 30-50% by weight of aluminum oxide and 50-70% by weight of yttrium oxide on an object requiring plasma resistance, and then a second coating film with higher density and plasma resistance is formed on the first coating film by aerosol deposition. The manufacturing technology provides plasma resistance, high voltage resistance, and high electrical resistance.

[0014] In addition, Korean Patent Publication No. 10-2017-0080123 (July 10, 2017) relates to a plasma-resistant coating film, specifically describing a manufacturing technology for a plasma-resistant coating film that can simultaneously ensure chemical resistance by minimizing open channels and open pores in the coating layer through double sealing by aerosol deposition and hydration treatment after thermal spray coating of a first rare earth metal compound, and plasma corrosion resistance by a dense rare earth metal compound coating film.

[0015] However, the plasma-resistant coating film having multiple coating layers manufactured according to the prior art still has problems of peeling and particle generation that may occur due to a decrease in bonding strength between the coating layers, and therefore, a technology for manufacturing a plasma-resistant coating film having durability and long life characteristics is required.

[0016] Therefore, the inventors realized that there were limitations to the manufacturing method of such plasma-resistant coating films, and as a result of extensive research into a manufacturing method of a thin film with excellent plasma resistance while optimizing the bonding strength between coating layers, they arrived at the present invention. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Korean Patent Publication No. 10-2013-0123821 [Patent Document 2] Korean Patent Publication No. 10-2017-0080123 Summary of the Invention [Problem to be solved by the invention]

[0018] A main object of the present invention is to provide a method for producing a plasma-resistant coating film that has excellent bonding strength and suppresses the formation of structural defects in the coating film, thereby minimizing peeling of the coating film or generation of particles during semiconductor manufacturing processes.

[0019] Another object of the present invention is to provide a plasma-resistant member having a plasma-resistant coating film formed thereon using the method for producing a plasma-resistant coating film. [Means for solving the problem]

[0020] In order to achieve the above object, one embodiment of the present invention provides a method for manufacturing a plasma-resistant coating film, which comprises the steps of: (a) forming a lower coating layer on an object to be coated by a physical vapor deposition process using a first rare earth metal compound powder; (b) transporting a second rare earth metal compound powder; and (c) spraying the transported second rare earth metal compound powder toward the lower coating layer formed in step (a) to form an upper coating layer.

[0021] In a preferred embodiment of the present invention, the first rare earth metal compound powder and the second rare earth metal compound powder may be of the same component.

[0022] In one preferred embodiment of the present invention, the rare earth metal compound powder may be selected from the group including yttria (Y2O3), yttrium fluoride (YF), yttrium oxyfluoride (YOF), and YAG (Yttrium Aluminum Garnet).

[0023] In a preferred embodiment of the present invention, the physical vapor deposition may be any one selected from the group consisting of thermal evaporation, electron beam evaporation, and sputtering.

[0024] In a preferred embodiment of the present invention, the thickness of the lower coating layer may be 0.1 to 10 μm.

[0025] In a preferred embodiment of the present invention, the second rare earth metal compound powder may have an average diameter (D50) of 0.1 to 10 μm.

[0026] In a preferred embodiment of the present invention, the upper coating layer may have a thickness of 1 to 30 μm.

[0027] In another preferred embodiment of the present invention, the present invention provides a plasma-resistant coating film produced by the method for producing a plasma-resistant coating film. [Effects of the Invention]

[0028] In the method for manufacturing a plasma-resistant coating film according to the present invention, a first rare earth metal compound is applied to a lower coating layer by physical vapor deposition, and in the step of spraying a second rare earth metal compound powder to form an upper coating layer, the lower coating layer can absorb the impact that the second rare earth metal compound powder applies to the coating target, thereby minimizing the occurrence of structural defects that may occur in the upper coating layer containing the second rare earth metal compound.

[0029] The plasma-resistant coating film produced by the present invention exhibits properties such that structural defects in the coating film are minimized, thereby reducing porosity that may occur due to structural defects, and improving the physical strength of the coating film. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic diagram showing the energy conversion that occurs when a rare earth compound powder is sprayed onto an object to be coated to form a rare earth metal compound coating layer. [Figure 2] 1 is a scanning electron microscope (SEM) photograph of the side of a coating film prepared according to Comparative Example 1. [Figure 3] 1 is a scanning electron microscope (SEM) photograph of the side of the coating film prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention belongs. Generally, the nomenclature used herein is that which is well known and commonly used in the art.

[0032] Throughout this specification, when a part "comprises" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless specifically stated to the contrary.

[0033] FIG. 1 is a schematic diagram showing the energy conversion that occurs when a rare earth compound powder is sprayed onto an object to be coated to form a rare earth metal compound coating layer.

[0034] As shown in FIG. 1, when a rare earth compound powder is sprayed onto an object to be coated to form a rare earth metal compound coating layer, the kinetic energy of the rare earth compound powder is converted into thermal energy and crushing energy, which can generate structural defects such as cracks in the object to be coated and the coating layer.

[0035] To overcome these problems, the present invention provides a method for manufacturing a plasma-resistant coating film that can minimize structural defects that occur in the rare earth metal compound coating layer, thereby reducing the porosity of the coating film and improving the physical strength of the coating film.

[0036] From one aspect of the present invention, a method for manufacturing a plasma-resistant coating film includes the steps of: (a) forming a lower coating layer on an object to be coated by a physical vapor deposition process using a first rare earth metal compound powder; (b) transporting a second rare earth metal compound powder; and (c) spraying the transported second rare earth metal compound powder toward the lower coating layer formed in step (a) to form an upper coating layer, wherein the first rare earth metal compound powder and the second rare earth metal compound powder are of the same composition.

[0037] First, in the method for forming a plasma-resistant coating film according to the present invention, a lower coating layer is formed on an object to be coated by a physical vapor deposition process using a first rare earth metal compound powder [Step (a)].

[0038] The coating target on which the lower coating layer containing the first rare earth metal compound is formed is a plasma device part such as an electrostatic chuck, a heater, a chamber liner, a shower head, a CVD boat, a focus ring, or a wall liner, which is applied inside a plasma device. The material of the coating target may be, but is not limited to, metals such as iron, magnesium, aluminum, and alloys thereof; ceramics such as SiO2, MgO, CaCO3, and alumina; and polymers such as polyethylene terephthalate, polyethylene naphthalate, polypropylene adipate, and polyisocyanate.

[0039] The first rare earth metal compound may include yttria (Y2O3), yttrium fluoride (YF), yttrium oxyfluoride (YOF), YAG (yttrium aluminum garnet), or a mixture thereof, and is preferably yttria (Y2O3).

[0040] The first rare earth metal compound forming the lower coating layer has strong resistance to plasma exposed during semiconductor processing, and therefore when applied to semiconductor equipment parts that require corrosion resistance, such as semiconductor etching equipment, it ensures corrosion resistance and voltage resistance characteristics against plasma used in semiconductor processing.

[0041] The formation of the lower coating layer on the coating object may be performed by any physical vapor deposition method that can form a coating layer that satisfies requirements such as strong bonding strength between the coating object and the coating layer and corrosion resistance. Specifically, the physical vapor deposition may be any method selected from thermal evaporation, electron beam evaporation, and sputtering, and preferably electron beam evaporation.

[0042] The lower coating layer containing the first rare earth metal compound in step (a) is a layer formed by coating the first rare earth metal compound on the object to be coated using a physical vapor deposition method. Since the lower coating layer can be etched during the process of forming the upper coating layer, it is preferable to increase the thickness of the lower coating layer as the hardness of the rare earth metal compound powder forming the upper coating layer increases or the heat treatment temperature of the rare earth metal compound powder increases. Alternatively, since the amount of etching of the lower coating layer increases as the nozzle angle decreases during the process of forming the upper coating layer, it is preferable to increase the thickness of the lower coating layer.

[0043] In one embodiment, the thickness of the lower coating layer is preferably 0.1 to 10 μm. If the thickness of the lower coating layer is less than 0.1 μm, there is a risk that the lower coating layer may not be partially formed. If the thickness is more than 10 μm, there is a risk that the process cost increases, which reduces the economic efficiency.

[0044] Thereafter, a carrier gas is supplied to transport the second rare earth metal compound powder, thereby transporting the second rare earth metal compound powder [step (b)].

[0045] In this case, the carrier gas may be provided at a flow rate of 15 to 200 slm (standard liter per minute), and may include an inert gas such as argon.

[0046] Next, the second rare earth metal compound powder is sprayed toward the lower coating layer formed on the object to be coated, thereby forming an upper coating layer containing the second rare earth metal compound, thereby forming a plasma-resistant member including the object to be coated and a rare earth metal compound coating film [step (c)].

[0047] The second rare earth metal compound may include yttria (Y2O3), yttrium fluoride (YF), yttrium oxyfluoride (YOF), YAG (yttrium aluminum garnet), or a mixture thereof, and is preferably yttria (Y2O3).

[0048] In this case, it is preferable that the first rare earth metal compound, which is a component of the lower coating layer, and the second rare earth metal compound, which is a component of the upper coating layer, are the same component. By making the lower coating layer and the upper coating layer the same component, the internal stress of the coating film can be minimized, thereby forming a stable coating film.

[0049] By the heat treatment process according to the present invention, the second rare earth metal compound powder has an average diameter (D50) of 0.1 to 10 μm, and therefore, when the second rare earth metal compound powder is used to form the upper coating layer, the density, strength, and adhesive force of the coating film are improved.

[0050] The upper coating layer containing the second rare earth metal compound is preferably a high density rare earth metal compound having a thickness of 1.0 to 30 μm and a porosity content of less than 1.0 vol %.

[0051] The upper coating layer has a problem in that the mechanical strength of the finally formed plasma-resistant coating film decreases as the porosity increases. Therefore, it is preferable that the upper coating layer containing the second rare earth metal compound has a low porosity and is dense to ensure the mechanical strength of the plasma-resistant coating film.

[0052] However, when a coating film is formed using a deposition method in which rare earth metal compound powder is transported using a carrier gas and then deposited in a vacuum chamber through a nozzle, the coating film generally has a nanoscale crystalline structure including numerous grain boundaries, and structural defects such as cracks are generated due to the fracture energy generated during deposition, resulting in poor mechanical properties.

[0053] Therefore, in the present invention, by applying the first rare earth metal compound to the lower coating layer by physical vapor deposition, the lower coating layer can absorb the thermal energy and spallation energy that the second rare earth metal compound powder applies to the coating object during the step of manufacturing the upper coating layer, thereby minimizing the occurrence of structural defects that may occur in the coating film.

[0054] Furthermore, if the thickness of the upper coating layer is less than 1 μm, it is difficult to ensure plasma resistance in a plasma environment due to its thinness, and if the thickness of the upper coating layer is more than 30 μm, peeling of the upper coating layer may occur during processing, which may result in economic losses due to excessive use of rare earth metal compounds.

[0055] In one embodiment, the deposition of the second rare earth metal compound powder using a carrier gas to form the upper coating layer involves loading the second rare earth metal compound powder into a vacuum chamber, placing the object to be coated on which the lower coating layer has been formed, in the deposition chamber, and then supplying the second rare earth metal compound powder from the vacuum chamber and spraying it into the deposition chamber via the carrier gas.

[0056] The carrier gas may be argon (Ar) gas, compressed air, or an inert gas such as hydrogen (H2), helium (He), or nitrogen (N2). Due to the pressure difference between the second rare earth metal compound powder supply device and the deposition chamber, the second rare earth metal compound powder is sucked into the deposition chamber together with the carrier gas and then sprayed at high speed through a nozzle toward the coating target (base material) on which the lower coating layer is formed.

[0057] The second rare earth metal compound is deposited by the spraying, forming an upper coating layer containing a high density of the second rare earth metal compound. The deposition area of ​​the second rare earth metal compound coating layer can be controlled to a desired size by moving the nozzle left and right, and its thickness is also determined proportionally depending on the deposition time, i.e., the spraying time.

[0058] The upper coating layer can also be formed by repeatedly depositing the second rare earth metal compound powder two or more times using the above-mentioned vapor deposition method.

[0059] The present invention also provides a plasma-resistant coating film manufactured by the method for manufacturing a plasma-resistant coating film, and the plasma-resistant coating film has low porosity and exhibits improved physical strength.

[0060] The present invention will be described in more detail below with reference to examples. However, the following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

[0061] Comparative Example 1 Deposition is carried out in a vacuum chamber under low vacuum conditions, with the maximum attainable vacuum being 10 mTorr, and the process vacuum formed when a carrier gas is supplied is 0.5 to 5 Torr.

[0062] The yttria (Y2O3) powder is supplied uniformly at a constant rate via a supply device. The size of the supplied yttria (Y2O3) powder is several μm to several tens of μm, and the powder supply rate is controlled at a level of 5 to 50 g / min.

[0063] The supplied powder is entrained in the flow of carrier gas and finally sprayed through a nozzle in the chamber. The flow rate of the supplied carrier gas is 15 to 200 SLM, and the type of gas used is an inert gas such as Ar, N2, or He.

[0064] When the carrier gas is supplied, the pressure difference that occurs between the powder supply device and the vacuum chamber causes the carrier gas to be sucked into the vacuum chamber, and the gas flow that occurs at that time causes the powder to mix with the carrier gas and be transported.

[0065] The transported powder particles continue to accelerate due to the pressure difference, and when they are ejected through the nozzle, their speed reaches the speed of sound. The accelerated powder particles collide with the base material, and the collision energy generated at this time forms a 10 μm thick yttria coating film.

[0066] Examples 1 to 4 The coating material or process conditions for AD coating may vary depending on the thickness of the PVD coating layer. If the PVD coating layer is thin, a coating material or process conditions with a low etching rate must be used. If the material or process conditions have a high etching rate, the PVD coating may be completely etched, so the PVD coating thickness must be increased. Therefore, the PVD coating layer thickness should be 0.5, 1.0, 1.5, or 3.0 μm depending on the AD coating material and process conditions.

[0067] An example of a bottom layer coated by electron beam evaporation of physical and chemical vapor deposition techniques is as follows.

[0068] First, the alumina substrate is polished to a mirror finish, and then loaded into a coating chamber together with the raw material yttria (Y2O3), and a high vacuum atmosphere is maintained. At this time, the chamber temperature is maintained below 300°C.

[0069] Once the chamber reaches a high vacuum, the yttria (Y2O3) is irradiated with an electron beam to melt it and deposit it onto the base material, with ion assist applied to improve the physical properties of the coating layer.

[0070] Coating is performed by adjusting the coating time so that the final coating layer thickness becomes 0.5, 1.0, 1.5, or 3.0 μm.

[0071] On the PVD coatings of each thickness prepared as described above, an AD coating was deposited in the same manner as in the comparative example.

[0072] [Table 1]

[0073] As shown in Table 1, the plasma-resistant coating films according to the present invention (Examples 1 to 4) exhibit reduced porosity in the AD coating layer, which may occur due to structural defects, and improved physical strength of the coating film, compared to the coating film not including a PVD undercoating film (Comparative Example 1).

[0074] Although the specific parts of the present invention have been described in detail above, it will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the present invention. Therefore, the true scope of the present invention should be defined by the appended claims and their equivalents.

Claims

1. (a) forming a lower coating layer on an object to be coated by a physical vapor deposition process using a first rare earth metal compound; (b) conveying a second rare earth metal compound powder; (c) spraying the transported second rare earth metal compound powder toward the lower coating layer formed in step (a) to form an upper coating layer; The rare earth metal compound powder is yttria (Y ２ O ３ ), yttrium oxyfluoride (YOF), YAG (Yttrium Aluminum Garnet), the first rare earth metal compound powder and the second rare earth metal compound powder are the same component, and the lower coating layer and the upper coating layer are the same component, The physical vapor deposition is any one selected from the group consisting of thermal evaporation, electron beam evaporation, and sputtering; The thickness of the lower coating layer is 0.1 to 10 μm. A method for producing a plasma-resistant coating film, comprising:

2. 2. The method for producing a plasma-resistant coating film according to claim 1, wherein the second rare earth metal compound powder has an average diameter (D50) of 0.1 to 10 μm.

3. 2. The method for manufacturing a plasma-resistant coating film according to claim 1, wherein the thickness of the upper coating layer is 1 to 30 μm.

Images