KR20120078936A - Ceramic coated metal susceptor and method for manufacturing thereof - Google Patents

Abstract

PURPOSE: A ceramic coated metal susceptor and a manufacturing method thereof are provided to block a penetration path of a reaction gas through the interface of a crystalline structure by forming dense nitride layer when a surface of ceramic is nitride. CONSTITUTION: A metal plate body(110) includes a heated plane for heating materials. A heating element(130) is laid in the metal plate body. A heat transfer fluid(140) is laid between the metal plate body and the heating element. A metal supporting shaft(120) is combined on the bottom of the metal plate body. An anti-corrosion ceramic layer(170) is coated on the outer surface of the metal plate body and the metal supporting shaft.

Description

Ceramic Coated Metal Susceptor and Method for Manufacturing

The present invention relates to a ceramic coated metal susceptor, and more particularly to a ceramic coated metal susceptor for heating a wafer.

The applicant has applied for a ceramic coated heater module in patent application No. 2008-137706.

Vacuum plasma equipment is widely used in the process field for the implementation of semiconductor devices or other ultrafine shapes. Examples of vacuum plasma equipment used include plasma enhanced chemical vapor deposition (PECVD) equipment that forms a deposited film by chemical vapor deposition on a substrate, sputtering equipment that forms a deposited film by a physical method, and a substrate or a coated material on the substrate. Dry etching equipment for etching in a desired pattern.

Vacuum plasma equipment implements the etching or ultra-fine shape of the semiconductor device using a high temperature plasma. Therefore, a high temperature plasma is generated inside the vacuum plasma equipment, and the chamber and its internal parts are damaged.

In addition, there is a high possibility that certain elements and contaminating particles are generated from the surface of the chamber and its parts, contaminating the inside of the chamber. In particular, since the plasma etching equipment injects reactive gases including F and Cl into the plasma atmosphere, the chamber inner wall and its internal parts are placed in a very corrosive environment. This corrosion primarily causes damage to the chamber and its internal components, and secondly, contaminants and particles are generated, leading to an increase in defect rate and deterioration of the product produced through the process inside the chamber.

Examples of the etching gas include a gas containing F, such as C4F8, C5H8, CH2F2, CF, CF2, CF3, CF4, SF6, NF3, F2, CH2F2, CHF3, C2F6, and Cl, Cl2, BCl3, SiCl4, HCl, and the like. Gas containing Br, such as gas, HBr, Br2, CF3Br, and other gases such as SiN4, O2, Ar, H2, or the like.

However, the etching gas may affect not only the substrate to be etched but also other places. In other words, the chamber of the etching equipment and its internal components are also subjected to chemical / physical damage by the extreme atmosphere inside the chamber during the manufacturing process. The etching process is a process that removes the damaged part after applying a physical-chemical impact on the part or the front surface of the substrate by using corrosive gas, accelerated ions, and plasma, and thus removes the damaged part. In more detail, the chamber and the internal components are subjected to a chemical attack by an etching gas having high chemical reactivity. At the same time, the ionized gas particles are accelerated by the RF electromagnetic field and undergo a physical attack, which bombards the surface of the part. As such, if the chamber and the internal parts are damaged by the above process, a part of the damaged etching equipment must be replaced or cleaned / repaired, and thus additional costs are required. In addition, the processing time of the product is increased because the process line must be stopped for equipment replacement or cleaning / repair.

Therefore, metal susceptors installed inside existing chambers have been replaced with ceramic susceptors. The ceramic susceptor is composed of aluminum nitride sintered body with good thermal conductivity.

However, ceramic susceptors have the disadvantage of being expensive and inferior in durability to metals.

In Korean Patent No. 47388, a technique of ceramic coating the exterior of a metal susceptor is introduced. Ceramic coated metal susceptors are less expensive and more durable than ceramic susceptors.

However, the ceramic coating technology should consider the coefficient of thermal expansion with the metal, and if the inner metal surface is exposed due to cracking during use, there is a concern that the exposed metal surface will be contaminated as well as the inside of the chamber. Especially in the case of ceramic coating susceptors, damage to the coating layer was mainly found at the corners of the heating plate rather than the center portion.

The reason is that due to the plasma spray coating technique, a large number of cracks are generated in the vertical direction inside the splat formed by the impact of individual droplets on the surface of the base material. In addition to poor hardness (eg hardness), cracks and splat boundary gaps within the splat act as diffusion channels for the reactant gases. Therefore, it promotes the corrosion reaction of the coating layer and eventually accelerates the formation of contaminated particles. In addition, the coating layer was easily damaged by the mechanical impact applied during the semiconductor manufacturing process or cleaning.

An object of the present invention for solving the above problems is to provide a ceramic coated metal susceptor and a method of manufacturing the same that can form a stable coating layer at the corners.

Another object of the present invention is to provide a ceramic coated metal susceptor and a method of manufacturing the same, which can block a passage of the reaction gas of the coating layer.

Another object of the present invention is to provide a ceramic coated metal susceptor capable of completely covering lift pin holes and a method of manufacturing the same.

It is still another object of the present invention to provide a ceramic coated metal susceptor and a method of manufacturing the same, which can extend the life of the susceptor.

The ceramic-coated metal susceptor of the present invention for achieving the above object has a heating plate for heating the object to be heated and the rounded corners of the metal plate body, the heating element embedded in the metal plate body, and the heating plane of the metal plate body and And a thermally conductive fluid embedded between the heating elements, a metal support shaft coupled to the center of the bottom surface of the metal plate body and extending downward, and a corrosion resistant ceramic layer coated on the outer surface of the metal plate body and the metal support shaft.

In the present invention, it is preferable that a buffer layer is further formed between the anti-corrosion ceramic layer and the metal plate to buffer thermal stress, and the buffer layer is a bonding layer containing nickel, which not only moderates the thermal stress between the anti-corrosion ceramic layer and the metal plate. Ensure that the corrosion resistant ceramic layer is well bonded.

In the present invention, the anti-corrosion ceramic layer is any one of oxide powders such as Y2O3, Al2O3, ZrO2, CeO2, nitride powders such as AlN and BN, carbide powders such as SiC and AlC, and combinations of the oxide powders, nitride powders and carbide powders. It is enough. In particular, the anti-corrosion ceramic layer is preferably an oxide powder such as Y 2 O 3, Al 2 O 3, ZrO 2, CeO 2, and further includes a nitride layer formed by surface-nitriding the ceramic layer in a nitride gas atmosphere.

In addition, in the present invention, a plurality of lift pin holes penetrated to the bottom surface are formed on the heating plane of the metal plate body, and a ceramic tube is inserted into each lift pin hole to protect the surface of the metal plate body exposed to the inner wall of the through hole, which is difficult to coat, from corrosion. In this case, the length of the ceramic tube is shorter than the axial length of the through hole, and the edges of the metal plates of both ends of the through hole are preferably rounded. In particular, since coating damage is frequently generated around the lift pin through the plasma spray coating, it is preferable to form a step to form a rounding process and a shorter tube length within 10% to compensate for this.

The manufacturing method of the present invention comprises the steps of preparing a metal plate body having a heating plane for heating the object to be heated and rounded corners, embedding a heating element and a heat conducting fluid in the prepared metal plate body, the lower surface of the metal plate body Joining the metal support shafts extending to each other, inserting the ceramic tubes into the plurality of lift pin holes of the metal plate body, respectively, and forming a nickel-containing buffer layer on the outer surface of the metal plate body and the metal support shaft; And forming an alumina corrosion protection layer on the buffer layer.

In the manufacturing method of the present invention, it is further preferable to block the passage of the reaction gas through the interface, further comprising forming a nitride layer on the surface of the corrosion resistant layer by heat treatment in a nitrogen gas atmosphere after forming the corrosion resistant layer.

In the ceramic coating susceptor according to the embodiment of the present invention, since the ceramic layer is coated on the surface of the metal plate with rounded corners through the buffer layer, the ceramic layer is stably coated at the corners, thereby extending the life of the ceramic layer at the corners. Since the buffer layer absorbs the thermal stress due to the difference in the coefficient of thermal expansion between the metal plate and the ceramic layer due to the temperature change, the heat resistance may be improved and the durability may be strong even against mechanical impact. In addition, since the dense nitride layer is formed by nitriding the ceramic surface, it is possible to block the passage of the reaction gas through the interface of the crystal structure.

1 is a view showing a planar structure of a ceramic coated metal susceptor according to the present invention.
2 is a cross-sectional view taken along the line AA of FIG.
3 shows an enlarged cross-sectional structure of part X of FIG.
Figure 4 is a process flow chart for explaining a method for manufacturing a ceramic coated metal susceptor according to the present invention.
5 is a view showing a state in which the anti-corrosion ceramic layer is coated with a nitride layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the accompanying drawings. As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In general, a chemical vapor deposition method (CVD) is one of the thin film formation processes required in the semiconductor integrated circuit process. This deposition method is a step of forming a thin film on a semiconductor wafer while injecting one or more kinds of compound gases into a reaction chamber prepared for a CVD process to cause a chemical reaction in a vapor phase with a semiconductor wafer heated to a high temperature. A general description of a conventional CVD apparatus for performing such a CVD process includes a reaction chamber, a vacuum pump necessary for evacuating the reaction chamber, a gas supply port for introducing a reactive gas into the chamber, an exhaust port, and a heater. It is composed of modules.

The heater module is used to heat the semiconductor wafer so that the semiconductor wafer is chemically reacted with the reactive gas introduced at a high temperature. The heater module includes a susceptor with a heating wire to directly seat and heat the semiconductor wafer. It consists of a power supply line for supplying, and a support shaft for introducing a power supply line into the chamber.

With this configuration, if the chamber is vacuumed using a vacuum pump and the semiconductor wafer is heated to a high temperature through the heater module, and the reactive gas is introduced through the gas supply unit, the reactive gas is easily vacuumed because the inside of the chamber is in a high vacuum state. Rapidly and evenly scattered into the chamber, the scattered gas chemically reacts with the silicon wafer surface heated to a high temperature, forming a thin film on the wafer. The deposition rate of the thin film deposited on the wafer is greatly affected by the temperature of the wafer. For example, even if the film is deposited under the same conditions, the thickness of the film deposited at a high temperature of the wafer is thicker than that of the film deposited at a low temperature. Therefore, the temperature uniformity of the upper surface of the susceptor on which the wafer is seated is the biggest factor that determines the thickness uniformity of the CVD thin film.

1 shows a planar structure of a ceramic-coated metal susceptor according to the present invention, FIG. 2 shows a cross-sectional view taken along line A-A of FIG. 1, and FIG. 3 shows an enlarged cross-sectional structure of part X of FIG.

Referring to the drawings, the ceramic coated metal susceptor 100 of the present invention includes a circular metal plate body 110 and a metal support shaft 120. The heating element 130 and the thermal conductive fluid 140 are embedded in the metal plate 110, respectively.

The metal plate body 110 is arranged in the order of the wafer placing region 110a, the pocket line 110b, and the heating region 110c in a concentric manner from the center.

The metal plate 110 is made of a stainless steel material such as sus, a space portion 111 for embedding the heating element 130 is formed in the middle lower portion, and a space portion 112 for containing the heat conductive fluid 140 in the middle upper portion. ) Is formed. After installing the heating element 130, the space 111 covers the lower cover 113 and seals the cover edge by welding. Similarly, the space 112 is also filled with the heat conducting fluid 140, and then covers the top cover 114 and seals the edges by welding. The upper lid 114 is formed with a pocket jaw 115 to induce the wafer seating.

Here, the heating element 130 is disposed in the heating region 110c in a spiral shape in order to improve the isothermal characteristic with the conventional coil type heater. The heat conducting fluid 140 is provided as a working fluid for heat conduction in order to compensate for a relatively low temperature between the heat generating element 130 is arranged in a spiral line. Therefore, heat generated from the heating element 130 is quickly transferred to the heating surface of the metal plate body 110. Therefore, isothermality is maintained in the heating region of the metal plate body 110. Therefore, the entire surface is heated to a uniform temperature without a temperature deviation between the center and the edge of the wafer.

The corners of the metal plate body 110 and the metal support shaft 120 are rounded. In round processing, it is processed with a round radius of 0.1 to 1,5 mm. The ceramic tube 150 is assembled to the lift pin through hole 116. The ceramic tube 150 forms a step 117 near the edge of the aperture with a length about 10% shorter than the axial length of the aperture 116. The edge 118 of the inlet of the through hole 116 is rounded to a radius r (0.1 to 1.5 mm). Rounded edges 118 and step 117 around the perforations allow the ceramic layer 170 to form a round curved surface without coating at the edge of the lift pin through edges so as to dissipate thermal and mechanical stresses, resulting in mechanical strength and durability. This is improved. In addition, since the adhesive surface area is increased by round processing at the corners, the adhesive force between the buffer layer 160 and the ceramic layer 170 is increased to prevent coating errors or damage.

Figure 4 shows a process flow chart for explaining a method of manufacturing a ceramic coated metal susceptor according to the present invention.

First, the corners of the outer surfaces of the metal plate body 110 and the metal support shaft 120 are rounded to a radius of 0.1 to 1.5 mm (S100). Subsequently, the heating element 130 and the thermal conductive fluid 140 are sequentially embedded in the prepared metal plate 110. (S102). The susceptor is configured by welding the metal plate body 110 in which the heating element 130 and the thermal conductive fluid 140 are embedded and the metal support shaft 120 (S104).

Subsequently, the ceramic tubes 150 are respectively inserted into the plurality of lift pin through holes 116 of the metal plate 120 to be bonded (S106).

Using the plasma spraying equipment, the nickel-containing buffer layer 160 is sprayed to a thickness of about 20 to 100 μm, preferably about 50 μm, on the outer surfaces of the metal plate 110 and the metal support shaft 120 (S108). The nickel-containing buffer layer 160 preferably has a porosity of about 10 to 20%, preferably 12%. Such porosity serves to absorb thermal stress between the ceramic layer 170 and the metal plate 110 in the middle. do. Subsequently, the alumina corrosion preventing ceramic layer 170 is sprayed to a thickness of about 250 μm, preferably about 250 μm, on the buffer layer 160 (S110).

In the present invention, the grain size of the nickel-containing buffer layer 160 is preferably larger than the grain size of the ceramic layer 170. The ceramic layer 170 is preferably about 3 to 10%, preferably having a porosity of 5% or less. Physical or chemical attack due to corrosion and erosion of the metal plate by external aggressive environment can be minimized.

Plasma spray coating is generally a technique of injecting a metal or ceramic powder into a hot plasma flame to heat it, and then laminating it on the surface of the base material in a completely molten or semi-melted state to form a film. Liquid ceramics are loosely bonded to their constituent elements (eg Al2O3) and the order of the elements remains irregular. When the liquid ceramic is cooled below its melting point (Tm), it turns into a solid state, and the bonds between the elements become stronger and the arrangement of the elements changes into a crystalline phase formed regularly.

As such, the molten ceramic powder phase-transforms into a crystalline phase in the process of laminating and cooling the molten ceramic powder on the surface of the base metal during thermal spray coating to form cracks in the splat. It shows volume change when the liquid substance cools and transforms into a crystalline solid.

Therefore, in the present invention, in order to prevent penetration of the reaction gas through the splat crack or the splat interface, nitrogen gas is impregnated and heat treated between the cracks or the interface to form the nitride film coating by nitriding the splat surface. That is, the ceramic layer is thermally coated at about 600 to 700 degrees while the susceptor coated with the thermal spray coating is placed in a heat treatment chamber and injected with nitrogen gas, and as shown in FIG. 5, the nitride layer ( 180 is formed (S112). Therefore, the cracks and the spaces at the interface are filled during surface nitriding, blocking the passage of the reaction gas.

Although the ceramic coating metal susceptor according to the embodiments of the present invention has been described with reference to the drawings, the drawings and the description thereof are exemplary and ordinary in the art without departing from the spirit of the present invention. It may be modified and changed by one with knowledge. Therefore, the technical spirit of the present invention should not be limited to the embodiments of the present invention.

Claims (9)

A metal plate body having a heating plane for heating the object to be heated and having rounded corners;
A heating element embedded in the metal plate;
A heat conducting fluid buried between a heating plane of the metal plate and the heating element;
A metal support shaft coupled to a center of a bottom surface of the metal plate body and extending downward; And
And a corrosion resistant ceramic layer coated on the outer surface of the metal plate body and the metal support shaft. The ceramic coated metal susceptor of claim 1, further comprising a buffer layer for buffering thermal stress between the corrosion resistant ceramic layer and the metal plate. 3. The ceramic coated metal susceptor of claim 2 wherein the buffer layer is a bonding layer containing nickel. According to claim 1, wherein the corrosion-resistant ceramic layer is made of oxide powders such as Y2O3, Al2O3, ZrO2, CeO2, nitride powders such as AlN, BN, carbide powders such as SiC, AlC and oxide powders, nitride powders, carbide powders Ceramic coated metal susceptor, characterized in that any one of the combination. The ceramic coating metal sheet of claim 1, wherein the corrosion resistant ceramic layer is an oxide powder of Y 2 O 3, Al 2 O 3, ZrO 2, CeO 2, and the like, and further includes a nitride layer formed by surface nitriding the ceramic layer in a nitride gas atmosphere. Scepter. The ceramic-coated metal susceptor of claim 1, wherein a plurality of lift pin holes are formed in the heating plane of the metal plate, and a plurality of lift pin holes penetrate to the bottom surface. The ceramic coated metal susceptor of claim 6, wherein a length of the ceramic tube is shorter than an axial length of the through hole, and corners of the metal plate body at both ends of the through hole are rounded. Preparing a metal plate body having a heating plane for heating the object to be heated and rounded at an edge thereof;
Embedding a heating element and a heat conducting fluid in the prepared metal plate;
Coupling a metal support shaft extending downward to a bottom surface of the metal plate;
Inserting and coupling ceramic tubes into the plurality of lift pin holes of the metal plate, respectively;
Forming a nickel-containing buffer layer on an outer surface of the metal plate body and the metal support shaft; And
And forming an alumina corrosion protection layer on the buffer layer. The method of claim 8, further comprising forming a nitride layer on a surface of the corrosion protection layer by forming the corrosion protection layer and then performing heat treatment in a nitrogen gas atmosphere.

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