AlN Heater for Semiconductor Wafer and Manufacturing Method Thereof

Abstract

The present invention relates to an AlN heater for semiconductor wafers used in a wafer processing chamber and a method for manufacturing the same. Specifically, the invention relates to an AlN heater and a method for manufacturing the same, wherein a composition comprising yttria-stabilized zirconia (ZrO₂(Y₂O₃-stabilized)) and molybdenum disilicide (MoSi₂) is plasma-coated onto the surface of a heater made of a ceramic material. According to an embodiment of the present invention, by forming a high-density coating layer with a multilayer structure on the surface of the heating element of an AlN heater, the deterioration of the heating element due to long-term use can be minimized and resistance to thermal and mechanical stress can be increased, and the nano-composite coating layer (second coating layer) composed of SiC and BN acts as a perfect barrier against corrosive gases such as NF₃ and ClF₃, thereby extending the lifespan of the heating element in high temperature and corrosive environments.

Description

Technology Field

[0001] The present invention relates to an AlN heater for semiconductor wafers used in a wafer processing chamber and a method for manufacturing the same. More specifically, the invention relates to an AlN heater and a method for manufacturing the same, wherein a composition comprising yttria-stabilized zirconia (ZrO₂(Y₂O₃-stabilized)) and molybdenum disilicide (MoSi₂) is plasma coated onto the surface of a heater made of ceramic materials such as AlN, Al2O₃, Y2O₃, SiC, NITRIDE, and BORON NITRIDE. Background Technology

[0003] AlN heaters, which are ceramic heaters for semiconductor wafers, are products manufactured by sintering aluminum nitride. When used for a long time, surface damage (surface whitening and surface center cracking, etc.) occurs due to corrosive gases such as NF3 or ClF3, which are semiconductor process gases, and plasma uniformity defects occur due to the reduction of the dielectric layer caused by surface etching.

[0004] That is, aluminum nitride reacts strongly with corrosive gases containing F (fluorine) gas, such as NF3 and ClF3, at temperatures above 500°C to produce aluminum fluoride, specifically aluminum fluoride (Al F).

[0005] Aluminum fluoride formed on the heater surface in this way is a crystalline solid with a boiling point of 2,799 F (1,537°C), no melting point, a sublimation point of 2,356 F (1,291°C), and a water solubility of 0.56%. It is an insoluble organic solvent for acids and alkalis and is a major cause of particle contamination on semiconductor wafers when it adheres to the inside of the semiconductor chamber.

[0006] Therefore, in order to block these contaminants and improve the productivity of semiconductor manufacturing equipment, semiconductor processes must be carried out at high temperatures of 500°C or higher, so there is a need for the development of technology regarding new AlN heaters that can be used in high-temperature environments.

[0008] A related technology is disclosed in Korean Patent Publication No. 10-2014-0001023 (hereinafter referred to as 'Prior Art 1'). Prior Art 1 involves placing a contaminated AlN heater in a reaction chamber to remove Al fluoride generated in an AlN heater, introducing N2 gas to form a plasma, and then causing N+ ions excited by the plasma to sputter toward the Al fluoride of the contaminated AlN heater to remove the Al fluoride. As the N+ ions excited by the plasma are drawn toward the base material, i.e., the AlN heater, they break down the Al fluoride precipitated on the upper part of the AlN heater into small pieces, and then the N+ ions react with the AlF of the base material to be removed as volatile substances in the form of AlN and NF.

[0009] Another related technology is disclosed in Korean Published Patent No. 10-2016-0070917 (hereinafter referred to as 'Prior Art 2'). While Prior Art 1 is a technology for removing AlF already generated in an AlN heater, Prior Art 2 proposes a 'coating on the heater surface' that prevents the heater surface material from reacting with fluorine gas.

[0010] However, the coating layer of the Aerosol Deposition (AD) method disclosed in Prior Art 2 relies mainly on mechanical anchoring, so the bonding strength between the coating layer and the substrate is limited, and it is difficult to completely prevent micro-defects that occur during the high-speed spraying process of solid powder. In addition, the coating layer disclosed in Prior Art 2 has a thin thickness (5 to 10 μm), so there is a very high possibility that it will peel off due to thermal stress when used for a long time at high temperatures. Prior art literature

[0012] 1. KR 10-2014-0001023 A (Cleaning apparatus and cleaning method for an AlN heater for semiconductor manufacturing equipment) 2. KR 10-2016-0070917 A (Heater for a semiconductor wafer and method for manufacturing the same) 3. KR 10-1120599 B (Ceramic heater, method for manufacturing the same, and thin film deposition apparatus including the same) 4. KR 10-2685462 B (Ceramic heater for semiconductors) The problem to be solved

[0013] The present invention was devised to solve the above problems and aims to maximize corrosion resistance and enhance durability by increasing resistance to thermal and mechanical stress by coating the surface of a heating element in an AlN heater manufactured by a hot pressure sintering process, wherein AlN powder, a heating element (coil), AlN powder, RF mesh, and AlN powder are sequentially laminated. means of solving the problem

[0015] An AlN heater according to a preferred embodiment of the present invention is characterized by having a coating layer formed on the surface of one or more heating elements disposed inside a disk assembly (100) to block contact with a corrosive gas containing F (fluorine) gas of NF3 and ClF3.

[0016] In particular, the heating element of an AlN heater according to a preferred embodiment of the present invention is characterized by comprising, as shown in FIG. 5, a first coating layer comprising a composition consisting of molybdenum disilicide (MoSi₂) and yttria-stabilized zirconia (YSZ), and a second coating layer coated on top of the first coating layer, which is a nanocomposite coating layer of silicon carbide (SiC) and boron nitride (BN). FIG. 5 is a cross-sectional view showing the coating layer of a heating element according to a preferred embodiment of the present invention.

[0017] And, in order to form a double coating layer on the heating element, the method for manufacturing an AlN heater according to the present invention is,

[0018] A disc assembly (100) having one or more heating elements disposed therein and a shaft (200) attached to the bottom surface of the disc assembly (100) are manufactured, comprising the steps of: pre-treating the surface of the heating elements; a first coating step of forming a first coating layer on the surface of the heating elements; a first heat treatment step of heat-treating the first coating layer; a second coating step of forming a second coating layer on the surface of the first coating layer after the first heat treatment; and a stabilization step of heat-treating the heating elements a second time after the second coating step.

[0019] In particular, the present invention is characterized by a process for forming a first coating layer on the heating element, wherein the first coating layer is formed by plasma coating a mixed powder comprising molybdenum disilicide (MoSi₂) powder with a powder particle size of 10 to 50 μm and yttria-stabilized zirconia (YSZ) mixed in a mixing ratio of 80:20.

[0020] In addition, the present invention provides a process for forming a second coating layer on a first coating layer of the heating element, wherein a second coating layer with a thickness of 10 to 20 μm is formed by chemical vapor deposition (CVD) using silicon carbide (SiC) and boron nitride (BN) mixed in a weight ratio of 70:30, wherein the conditions for the chemical vapor deposition (CVD) are that the reactant gases are silane (SiH₄), methane (CH₄), boron trichloride (BCl₃), and ammonia (NH₃), the reaction temperature is 1,000 to 1,200°C, and the vacuum level is 10 -3 It is characterized by being Torr. Effects of the invention

[0022] According to the present invention having the above method and features, by forming a high-density coating layer on the surface of the heating element of an AlN heater, the deterioration of the heating element due to long-term use can be minimized and resistance to thermal stress and mechanical stress can be increased.

[0023] In addition, the nano-composite coating layer (second coating layer) composed of SiC and BN acts as a perfect barrier against corrosive gases such as NF₃ and ClF₃, thereby extending the lifespan of the heating element in high temperature and corrosive environments.

[0024] Furthermore, not only can the bonding strength between the heating element and the AlN substrate (thermal conductive layer) and the bonding strength between the heating element and the insulating layer be improved, but heat generated from the heating element can also be transferred more efficiently to the AlN substrate (thermal conductive layer). Brief explanation of the drawing

[0026] FIG. 1 is a bottom perspective view of an AlN heater according to an embodiment of the present invention. FIG. 2 is a perspective view showing a vertical cross- section of the AlN heater of the present invention. FIG. 3 is a plan view exemplarily illustrating a heating element embedded in an AlN heater according to an embodiment of the present invention. FIG. 4 is an explanatory diagram conceptually illustrating the pressure sintering process of a disk assembly according to an embodiment of the present invention. FIG. 5 is a cross-sectional view showing a coating layer of a heating element according to a preferred embodiment of the present invention. Specific details for implementing the invention

[0027] The present invention is capable of various modifications and may take various forms, and embodiments (aspects or examples) are to be described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed forms, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0028] The terms used in this specification are used merely to describe specific embodiments (aspects or examples) and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “comprising” or “consisting of” are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0029] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0030] The terms "~1~," "~2~," etc., described in this specification are used merely to distinguish different components and are not bound by the order of manufacture; furthermore, the names may not match those in the detailed description of the invention and the claims.

[0031] FIG. 1 is a bottom perspective view of an AlN heater according to one embodiment of the present invention, FIG. 2 is a perspective view showing a vertical cross-section of an AlN heater according to the present invention, and FIG. 3 is an exemplary illustration of a heating element embedded in an AlN heater according to one embodiment of the present invention.

[0032] AlN heaters can be implemented in various forms. For example, FIG. 1 illustrates an embodiment of an AlN heater (10) according to the present invention. The AlN heater (10) according to the present invention includes a disk assembly (100) and a shaft (200) attached to the bottom surface of the disk assembly (100).

[0033] The above disk assembly (100) comprises a first heat conductive layer (110) forming the upper surface of the disk assembly (100), an RF mesh layer (120) in which an RF mesh (121) is embedded and disposed below the first heat conductive layer (110), an insulating layer (130) provided below the RF mesh layer (120) to insulate between the RF mesh layer (120) and a heating element layer (140) described later, a heating element layer (140) composed of one or more heating elements (141), and a second heat conductive layer (150) formed below the heating element layer (110) and forming the bottom surface of the disk assembly (100).

[0034] The shaft (200) is generally hollow tubular and is coupled to the bottom surface of the disk assembly (100) and extends vertically from the bottom surface of the disk assembly (100). The connection portion (210) at the end of the shaft (200) is configured to engage with a feedthrough (not shown) or other structure to transfer the AlN heater (10) to an atmospheric environment outside the semiconductor wafer processing chamber.

[0035] The above disk assembly (100) may include an RF electrode rod (215) for electrically connecting to the RF mesh of the RF mesh layer (120) and sockets (not shown). The sockets are each electrically connected to one or more heating elements (141). The sockets are configured so that electrode rods (212) for supplying power to each of the one or more heating elements (141) are electrically connected.

[0036] A person skilled in the art will understand that the first thermal conductive layer (110) forming the upper surface of the disk assembly (100) is the wafer side, and the lower surface of the disk assembly (100) provides a connection portion to the outside of the wafer processing chamber.

[0037] The above disk assembly (100) may be composed of a disc or a plate and may have a circular, semicircular, or any other planar shape. According to the embodiment illustrated in the drawing, the disk assembly (100) has a circular planar shape and may be manufactured with any diameter, such as, for example, 150 mm, 200 mm, 300 mm, or 450 mm.

[0039] The heating element (141) embedded in the above disk assembly (100) may consist of one or more heating elements arranged in multiple zones. FIG. 3 illustrates an exemplary heating element consisting of a first heating element (141a) that heats the outer region of the disk assembly (100) and a second heating element (141b) that heats the inner region of the disk assembly (100). The AlN heater (10) according to the present invention may preferably be composed of four heating elements that are divided into four zones and each generate heat.

[0040] Here, according to a preferred embodiment of the present invention, an AlN heater is manufactured by filling a die (300) for pressure sintering with AlN powder to form a first heat conductive layer (110) as shown in FIG. 4, placing an RF mesh (121) thereon, filling the RF mesh (121) with high-insulating AlN powder to form an insulating layer (130), placing heating elements manufactured by dividing them into two or four zones on the high-insulating AlN powder, and finally filling the die (300) with high-thermal-conducting AlN powder to form a second heat conductive layer (150), and then manufacturing a disk assembly (100) through a hot pressure sintering process. The disk assembly (100) manufactured by the pressure sintering process is manufactured by processing it into an AlN heater shape using processing equipment.

[0041] It is preferable that the above AlN powder has an average particle size of 0.5 to 1.0 μm and a purity of 99.8% or higher.

[0042] In addition, the sintering temperature of the above-mentioned pressure sintering process is preferably 1,800 to 1,900°C, the sintering pressure is preferably 20 to 30 MPa, and the sintering is preferably performed for 1 to 4 hours. Furthermore, the above-mentioned pressure sintering process is preferably performed in a nitrogen (N₂) or argon (Ar) atmosphere to prevent oxidation and maintain chemical stability, and further includes a stabilization step in which residual stress is minimized by slowly cooling after sintering.

[0044] Here, the insulating layer (130) formed by the high-insulating AlN powder exhibits a leakage current blocking effect at high temperatures and acts as a barrier layer for heat conduction at high temperatures, thereby increasing the uniformity of the heating temperature of the heating element (minimizing temperature deviation).

[0045] An AlN heater (10) is manufactured by bonding the shaft (200) to the bottom surface of the disk assembly (100) produced by the above-described process and brazing it with an electrode terminal.

[0047] An AlN heater according to a preferred embodiment of the present invention is characterized by forming a coating layer on the surface of the heating element by coating the surface of the heating element to block the surface of the heating element (141) from coming into contact with corrosive gases containing F (fluorine) gas of NF3 and ClF3, protect the heating element (141) from high-temperature oxidation and deterioration, and maximize durability.

[0048] In particular, as a preferred embodiment of the present invention, the coating layer is characterized by being composed of a first coating layer (145) plasma-coated with a composition consisting of molybdenum disilicide (MoSi₂) and yttria-stabilized zirconia (YSZ), and a second coating layer (146) coated with silicon carbide (SiC) and boron nitride (BN) on the surface of the first coating layer by chemical vapor deposition (CVD).

[0049] The first coating layer (145) minimizes the difference in thermal expansion coefficients between the AlN powder and the surface of the heating element, thereby preventing peeling due to thermal stress, and further improves stability against high-temperature oxidation and mechanical strength.

[0050] In addition, the second coating layer (146) is a nanocomposite coating layer of SiC and BN, where SiC provides high thermal conductivity and chemical resistance, and BN provides a low coefficient of thermal expansion and excellent corrosion resistance. In particular, the second coating layer serves to protect the heating element by blocking direct contact with corrosive gases such as NF₃ and ClF₃.

[0051] ...............

[0052] Molybdenum disilicide (MoSi₂) and yttria-stabilized zirconia (YSZ) constituting the first coating layer (145) are described.

[0053] First, molybdenum disilicide (MoSi₂) forms a SiO₂ protective film at high temperatures, making it highly resistant to oxidation and providing excellent high-temperature oxidation stability. It can also relieve thermal stress through high thermal conductivity (approx. 66 W / m·K), increase the heat transfer efficiency of the heating element, and provide excellent mechanical strength even at high temperatures, thereby strengthening the durability of the coating layer.

[0054] Furthermore, yttria-stabilized zirconia (YSZ) is zirconium dioxide (ZrO₂) stabilized by yttrium oxide (Y₂O₃). Because the stabilization treatment maintains a stable structure without phase transformation even at high temperatures, it not only ensures high-temperature stability but also possesses low thermal conductivity and a high coefficient of thermal expansion. This mitigates the difference in thermal expansion coefficients between molybdenum disilicide (MoSi₂) and the AlN substrate, and between MoSi₂ and the heating element, thereby preventing delamination. Additionally, stabilized ZrO₂ improves heat resistance and thermal shock resistance at high temperatures, and contributes to increasing the density of the coating layer and reducing crack formation by suppressing pore formation in the microstructure.

[0055] The mixing ratio of molybdenum disilicide (MoSi₂) and yttria-stabilized zirconia (YSZ) constituting the first coating layer is preferably 80:20 by weight. Since the first coating layer must perform the most important roles of high-temperature oxidation stability and thermal conductivity, it is highly desirable to set the ratio of molybdenum disilicide (MoSi₂) to 80 wt% to maximize the physical properties of MoSi₂. On the other hand, by setting ZrO₂ (Y₂O₃ stabilized) to 20 wt%, it is intended to perform the function of adjusting the thermal expansion coefficient of ZrO₂ and the auxiliary role of preventing pores and cracks.

[0056] The coefficient of thermal expansion of MoSi₂ is approximately 8.1 × 10⁻⁶ -6 / K (25~1400℃), and the coefficient of thermal expansion of ZrO₂ (Y₂O₃ stabilized) is approximately 10.5 × 10⁻⁶ -6 Considering that the thermal expansion coefficients of the two materials are / K (25~1200℃), setting the ratio of MoSi₂:ZrO₂(Y₂O₃ stabilized) to 80:20 wt% can minimize the difference in thermal expansion coefficients between the AlN substrate, the heating element, and the coating layer. This is a very important factor in preventing delamination and cracking caused by thermal stress.

[0057] If the ratio of MoSi₂ to ZrO₂ increases, the role of ZrO₂ (mitigating the difference in thermal expansion coefficients) decreases, causing the thermal stress between the first coating layer and the heating element to increase, which ultimately increases the likelihood of delamination or cracking. Furthermore, due to a lack of ZrO₂, the density of the coating layer decreases, increasing the likelihood of micropores and cracks occurring. If the impact resistance of ZrO₂ decreases, the resistance to rapid temperature changes (thermal shock) weakens, which may ultimately lead to a decrease in the long-term durability and thermal stability of the first coating layer.

[0058] Conversely, if the ratio of ZrO₂ to MoSi₂ increases (the ratio of MoSi₂ decreases), ZrO₂ has low thermal conductivity (about 2.5 W / m·K), so the thermal conductivity of the entire first coating layer decreases, thereby lowering the heat release efficiency of the heating element, and the amount of the SiO₂ protective film formed by MoSi₂ decreases, weakening oxidation resistance. Furthermore, since ZrO₂ has lower mechanical strength than MoSi₂, the mechanical strength of the first coating layer is weakened, and consequently, there is a high possibility that the thermal stability and oxidation resistance of the first coating layer will decrease.

[0059] Accordingly, in a preferred embodiment according to the present invention, by configuring the ratio of MoSi₂ and ZrO₂ (Y₂O₃ stabilized) to a ratio of 80:20 wt%, the advantages of MoSi₂ and ZrO₂ (Y₂O₃ stabilized) can be optimized, and the performance of the first coating layer, such as high-temperature oxidation stability, mitigation of differences in thermal expansion coefficients, and prevention of pores and cracks, can be maximized.

[0060] The explanation regarding the plasma coating treatment of the first coating layer above will be described in detail in the explanation regarding the 'method for manufacturing an AlN heater' to be described later.

[0061] ...............

[0062] Next, the second coating layer (146), which is a nanocomposite coating layer of silicon carbide (SiC) and boron nitride (BN), will be described.

[0063] The second coating layer (146) is a composite thin film layer of SiC-BN coated on the surface of the first coating layer (145) by chemical vapor deposition (CVD). This composite thin film layer has excellent wear resistance, chemical resistance, and heat resistance, and maintains a stable thin film layer even in a corrosive gas environment (NF₃, ClF₃, etc.).

[0064] The above SiC is deposited on the surface of the first coating layer in the form of a single crystal (4H-SiC or 6H-SiC) or a polycrystalline form by gaseous precursors (SiH₄(Silane) and CH₄(Methane)) in a CVD process. It is very hard (Mohs hardness 9), has excellent wear resistance, and exhibits stable heat resistance even at high temperatures of 1,600°C or higher. In addition, it has strong chemical resistance to corrosive gases and chemicals and high thermal conductivity (approx. 120 to 200 W / m·K).

[0065] Furthermore, the above BN is formed in a CVD process from gaseous precursors (BCl₃ (Boron Trichloride) and NH₃ (Ammonia)), specifically by supplying boron (B) from BCl₃ and nitrogen (N) from NH₃. The above BN is mainly formed in the form of hexagonal (h-BN) or cubic (c-BN); the hexagonal (h-BN) has a layered structure and excellent lubricity, while the cubic (c-BN) has high hardness comparable to that of diamond. The above BN exhibits stable heat resistance in high-temperature environments of up to 1,000°C or higher, displays very strong properties (chemical resistance) in oxidizing and corrosive environments, and possesses high insulation properties.

[0066] It is particularly preferable that the SiC of the second coating layer according to the present invention has a polycrystalline structure, and the BN of the second coating layer is cubic (c-BN).

[0067] In addition, the second coating layer is a SiC-BN composite thin film layer, and it is important that the optimal weight ratio of SiC to BN is 70:30. That is, in the present invention, by composing SiC at 70 wt%, SiC plays a primary role in providing chemical stability, thermal conductivity, mechanical strength, and durability in a high-temperature environment in the second coating layer, while 30 wt% of BN enables auxiliary properties. BN complements the disadvantages of SiC and plays a role in providing a low coefficient of thermal expansion and corrosion resistance; 30 wt% of BN is the optimal ratio that fully utilizes the properties of BN while allowing the mechanical strength and thermal conductivity of SiC to be exhibited as important properties. In particular, the 70:30 wt% ratio of the two materials constituting the second coating layer harmoniously combines the difference in the coefficients of thermal expansion of the two materials, thereby not only relieving stress and preventing crack formation, but also adjusting the coefficient of thermal expansion of the second coating layer to minimize the difference in thermal stress between the substrate and the underlying coating layer.

[0068] If the ratio of SiC to BN increases, the thermal expansion coefficient of SiC (approx. 4.6 × 10⁻⁶) -6 Since the thermal expansion coefficient of BN (K) is higher than that of BN, the difference in thermal expansion coefficients between the second coating layer and the first coating layer, and between the second coating layer and the AlN substrate (referring to the insulating layer (130) and the second thermal conductive layer (150)), increases, thereby increasing the possibility of cracking due to thermal stress. Additionally, if the proportion of SiC becomes excessively high, the contribution of BN to corrosion resistance and chemical stability decreases, which may weaken resistance to corrosive gases such as NF₃ and ClF₃.

[0069] Conversely, if the ratio of BN to SiC increases (the ratio of SiC decreases), the mechanical strength and hardness of SiC decrease, making the coating layer vulnerable to external impact or thermal stress. Also, since the thermal conductivity of BN (approximately 30 W / m·K) is lower than that of SiC, increasing the ratio of BN results in a problem where the thermal conductivity of the entire second coating layer decreases. Furthermore, while the layered structure of BN has the advantage of relieving thermal stress, if the ratio of BN becomes excessively high, the internal bonding strength of the second coating layer weakens, increasing the possibility of delamination.

[0070] Accordingly, in a preferred embodiment according to the present invention, by configuring the ratio of SiC to BN to be 70:30 weight%, the chemical stability, thermal stress relief, mechanical strength, and corrosion resistance of the second coating layer can be maximized. If this ratio is deviated from, vulnerability occurs in thermal stress, chemical resistance or thermal conductivity, mechanical strength, etc. Therefore, the SiC:BN combination ratio of 70:30 weight% is the optimal ratio for optimizing the performance of the second coating layer and ensuring stability in high temperature and corrosive environments.

[0071] The explanation regarding the chemical vapor deposition (CVD) of the second coating layer above will be described in detail in the explanation regarding the 'method for manufacturing an AlN heater' to be described later.

[0072] ............

[0073] The following describes the manufacturing method of an AlN heater.

[0074] An AlN heater (10) according to the present invention is manufactured by including a disk assembly (100) in which one or more heating elements are disposed inside, and a shaft (200) attached to the bottom surface of the disk assembly (100).

[0075] The method for manufacturing an AlN heater (10) according to the present invention is,

[0076] A first filling step of filling an AlN powder to form a first heat conductive layer (110) in a die (300) for pressure sintering; an RF mesh layer forming step of placing an RF mesh (121) on top of the AlN powder filled by the first filling step; a second filling step of filling a high-insulating AlN powder to form an insulating layer (130) on top of the RF mesh (121); a heating element layer forming step of placing a plurality of heating elements divided into two or four divided zones on top of the AlN powder filled by the second filling step; a third filling step of filling a high-thermal-conducting AlN powder to form a second heat conductive layer (150) on top of the heating element layer; and a disk forming step of manufacturing a disk assembly (100) by a hot pressure sintering process using the die (300) for pressure sintering; The process consists of a completion step in which a shaft (200) is bonded to the bottom surface of the manufactured disc assembly (100) and brazed with an electrode terminal to produce an AlN heater (10).

[0077] Here, it is preferable that the AlN powder has an average particle size of 0.5 to 1.0 μm and a purity of 99.8% or higher.

[0078] In addition, in the above disk forming step, the sintering temperature of the pressure sintering process is preferably 1,800 to 1,900℃, the sintering pressure is 20 to 30 MPa, and it is preferable to sinter for 1 to 4 hours.

[0079] In addition, the above-mentioned pressure sintering process is preferably sintered in a nitrogen (N₂) or argon (Ar) atmosphere to prevent oxidation and maintain chemical stability, and further includes a stabilization step of slowly cooling after sintering to minimize residual stress.

[0080] In particular, in the manufacturing method of the present invention, the step of forming the heating element layer is,

[0081] The method is characterized by comprising: a step of pre-treating the surface of the heating element; a first coating step of forming a first coating layer on the surface of the heating element; a first heat treatment step of heat-treating the first coating layer; a second coating step of forming a second coating layer on the surface of the first coating layer after the first heat treatment; and a stabilization step of secondarily heat-treating the heating element after the second coating step.

[0082] The step of pre-treating the surface of the heating element is a step of removing oxides, contaminants, and impurities from the surface of the heating element and forming surface roughness, and sandblasting is performed to achieve a surface roughness of Ra 3 to 5 μm to increase the adhesion of the coating layer. After sandblasting, oil and residues on the surface of the heating element are removed with alcohol or acetone to secure a clean surface.

[0083] And, the first coating step involves plasma coating a mixed powder in which molybdenum disilicide (MoSi₂) powder with a powder particle size of 10 to 50 μm and yttria-stabilized zirconia (YSZ) are mixed in a mixing ratio of 80:20 to form a first coating layer with a coating thickness of 50 to 100 μm.

[0084] In plasma coating the first coating layer, it is important to form a first coating layer of 50 to 100 μm by plasma coating at a plasma torch temperature of 15,000 to 20,000°C and a spray speed of 200 to 300 m / s.

[0085] The first heat treatment step is performed by heating at a temperature of 800 to 1,000°C for 2 to 4 hours. The purpose of the first heat treatment step is to densify the first coating layer and strengthen the bonding strength. Additionally, by undergoing the first heat treatment step, residual stress can be relieved to prevent peeling or cracking, and the chemical stability of the first coating layer can be improved. During this process, a thin SiO₂ protective film is formed on the MoSi₂ surface, which increases oxidation resistance. Furthermore, by undergoing the first heat treatment step, the first coating layer is densified and surface defects are reduced, thereby improving the bonding strength with the second coating layer described later.

[0086] In addition, the second coating step involves forming a second coating layer with a coating thickness of 10 to 20 μm by chemical vapor deposition (CVD) using silicon carbide (SiC) and boron nitride (BN) mixed in a weight ratio of 70:30. Here, the reactant gases in the chemical vapor deposition (CVD) are silane (SiH₄), methane (CH₄), boron trichloride (BCl₃), and ammonia (NH₃), the reaction temperature is 1,000 to 1,200°C, and the vacuum level is 10⁻³ Torr.

[0087] In addition, the stabilization step is a step of heat-treating the heating element, which has completed the second coating step, at a temperature of 1,000 to 1,200°C for 4 to 6 hours in an argon (Ar) or nitrogen (N₂) atmosphere. The stabilization step is intended to stabilize the multilayer structure of the heating element coating layer composed of the first coating layer and the second coating layer, and to relieve stress caused by the difference in thermal expansion coefficients to ensure the stability of the coating layer.

[0089] The present invention, as described above with reference to the attached drawings, is susceptible to various modifications and alterations by a person skilled in the art, and such modifications and alterations not limited by the claims should be interpreted as being included within the scope of the rights of the present invention. Explanation of the symbols

[0091] 10: AlN heater 100: Disk assembly 110: First thermal conductive layer 120: RF mesh layer 130: Insulation layer 140: Heating element layer 150: Second thermal conductive layer 200: Shaft

Claims

Claim 1 An AlN heater for processing a semiconductor wafer in a wafer processing chamber, wherein the AlN heater comprises a disk assembly (100) having one or more heating elements disposed therein and a shaft (200) attached to the bottom surface of the disk assembly (100), wherein a coating layer is formed on the surface of the heating element to block contact with a corrosive gas containing F (fluorine) gas of NF3 or ClF3, and wherein the coating layer comprises a first coating layer comprising a composition consisting of molybdenum disilicide (MoSi₂) and yttria-stabilized zirconia (YSZ), and a second coating layer coated on the upper surface of the first coating layer, the second coating layer being a nanocomposite coating layer of silicon carbide (SiC) and boron nitride (BN). Claim 2 delete Claim 3 An AlN heater according to claim 1, wherein the first coating layer is characterized in that the powder particle size of the molybdenum disilicide (MoSi₂) powder and the yttria-stabilized zirconia (YSZ) powder is 10 to 50 μm, the mixing ratio of the molybdenum disilicide (MoSi₂) powder and the yttria-stabilized zirconia (YSZ) powder is 80:20 by weight, and the coating thickness is 50 to 100 μm. Claim 4 An AlN heater according to claim 1 or 3, wherein the second coating layer is a nanocomposite coating layer in which silicon carbide (SiC) and boron nitride (BN) are mixed in a weight ratio of 70:30 and the coating thickness is 10 to 20 μm. Claim 5 A method for manufacturing an AlN heater comprising a disk assembly (100) having one or more heating elements disposed therein and a shaft (200) attached to the bottom surface of the disk assembly (100), wherein the method processes a semiconductor wafer in a wafer processing chamber, the method comprises: a step of pre-treating the surface of the heating element; a first coating step of forming a first coating layer on the surface of the heating element; a first heat treatment step of heat-treating the first coating layer; a second coating step of forming a second coating layer on the surface of the first coating layer after the first heat treatment; and a stabilization step of secondarily heat-treating the heating element after the second coating step, wherein the first coating step is characterized by forming a first coating layer by plasma coating a mixed powder in which molybdenum disilicide (MoSi₂) powder having a powder particle size of 10 to 50 μm and yttria-stabilized zirconia (YSZ) are mixed in a mixing ratio of 80:

20. Claim 6 A method for manufacturing an AlN heater according to claim 5, wherein the first coating step is characterized by forming a first coating layer of 50 to 100 μm by plasma coating the mixed powder at a plasma torch temperature of 15,000 to 20,000°C at a spray speed of 200 to 300 m / s. Claim 7 A method for manufacturing an AlN heater according to claim 6, wherein the first heat treatment step is characterized by heating at a temperature of 800 to 1,000℃ for 2 to 4 hours. Claim 8 In claim 6 or 7, the second coating step forms a second coating layer with a coating thickness of 10 to 20 μm by chemical vapor deposition (CVD) using silicon carbide (SiC) and boron nitride (BN) mixed in a weight ratio of 70:30, wherein the reactant gases in the chemical vapor deposition (CVD) are silane (SiH₄), methane (CH₄), boron trichloride (BCl₃), and ammonia (NH₃), the reaction temperature is 1,000 to 1,200°C, and the vacuum level is 10 -3 A method for manufacturing an AlN heater characterized by being Torr. Claim 9 A method for manufacturing an AlN heater according to claim 8, wherein the stabilization step is characterized by heat-treating the heating element that has completed the second coating step at a temperature of 1,000 to 1,200°C for 4 to 6 hours in an argon (Ar) or nitrogen (N₂) atmosphere to stabilize the multilayer structure of the heating element coating layer composed of the first coating layer and the second coating layer, and to relieve stress caused by the difference in thermal expansion coefficients to ensure the stability of the coating layer.

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