KR20150123075A - SiC-formed material and method of manufacturing the SiC-formed material - Google Patents

Abstract

A silicon carbide molded body formed by chemical vapor deposition has the electric resistivity of 0.01 to 10 Ωm, and the optical transmittance of 2.3 to 2.5%. Accordingly, the silicon carbide molded body formed by chemical vapor deposition has the low electric resistivity and optical transmittance, and can be appropriately used as a base material for a semiconductor manufacturing apparatus.

Description

[0001] The present invention relates to a silicon carbide formed body and a method of manufacturing the same,

More particularly, the present invention relates to a silicon carbide formed body that can be used as a heater for a semiconductor manufacturing apparatus, a dummy wafer, a susceptor, and the like, and a method of manufacturing the same.

Silicon carbide (SiC) has excellent material properties such as heat resistance, corrosion resistance, and strength characteristics, and is usefully used as various industrial members. Particularly, since the SiC compact (CVD-SiC compact) produced by the chemical vapor deposition (CVD) method is dense, high-purity and high in homogeneity of the structure, Are suitably used. For example, the CVD-SiC formed body can be used as a heater for semiconductor production, a dummy wafer, a susceptor, a core tube, or the like.

The CVD-SiC formed body may be obtained by vapor phase reaction of a source gas to deposit crystal grains of SiC on the surface of the substrate, forming a coating by growing crystal grains, and then removing the substrate.

For example, when used as a heater for semiconductor production, in addition to the above-described characteristics, a low resistivity such as SiC produced by a sintering method is required, and a low light transmittance is required when used as a dummy wafer. However, conventional CVD-SiC molded body manufacturing methods have failed to obtain SiC molded bodies having sufficient characteristics that can be generally used as base materials for semiconductor production.

The present invention provides a silicon carbide formed body having a low resistivity.

The present invention provides a method of manufacturing a silicon carbide formed body having a low resistivity.

The silicon carbide shaped body according to the present invention is formed by chemical vapor deposition and can have an electric resistivity of 0.01 to 10? M.

According to one embodiment of the present invention, the silicon carbide molded body may further have a light transmittance of 2.3 to 2.5%.

The method for manufacturing a silicon carbide formed body according to the present invention is a method for manufacturing a silicon carbide formed body by introducing a nitrogen gas together with a raw material gas and a carrier gas into a reaction chamber to form a silicon carbide film on the surface of the substrate by chemical vapor deposition, (1 / min) / carrier gas flow rate (l / min)) of the source gas introduced into the reaction chamber in which the chemical vapor deposition process in which the substrate is provided is 7.5% by volume, nitrogen The concentration of the gas (nitrogen gas flow rate (l / min) / source gas flow rate (l / min)) may be 0.5 to 5% by volume.

According to the silicon carbide formed article and the method of manufacturing the same of the present invention, since the silicon carbide formed article is formed by chemical vapor deposition, it has not only high denseness, high purity and other characteristics but also low resistivity and light transmittance. Therefore, the above-mentioned silicon carbide formed body can be suitably used as a substrate for various semiconductor manufacturing apparatuses.

FIG. 1 is a schematic view for explaining a chemical vapor deposition apparatus for manufacturing an SiC compact according to the present invention.

Hereinafter, a silicon carbide formed body according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are 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 on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are enlarged to illustrate the present invention in order to clarify the present invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a part or a combination thereof is described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

The SiC compact according to the present invention is formed by introducing nitrogen gas together with a raw material gas and a carrier gas into a reaction chamber, forming SiC on the surface of the substrate by a CVD process, and then removing the substrate.

FIG. 1 is a schematic view for explaining a chemical vapor deposition apparatus for manufacturing an SiC compact according to the present invention.

Referring to FIG. 1, the chemical vapor deposition apparatus 100 includes a reaction chamber 110, a source gas storage unit 120, a carrier gas storage unit 130, and a doping gas storage unit 140.

The reaction chamber 110 accommodates the substrate 10 therein. In addition, the reaction chamber 110 may have a heater (not shown) inside or outside thereof, and may have an exhaust port 112 for exhausting the inside thereof.

As the substrate 10, a graphite material can be used. The substrate 10 may have a substrate form for the production of a flat molded body. Further, the base material 10 may have a cylindrical shape for the production of a cylindrical or tubular shaped body.

The raw material gas storage part 120 stores the raw material gas. As the source gas, a silane-based gas such as methyltrichlorosilane (MTS) (SiCH 3 Cl 3), SiHCl 3 or SiH 4, or a hydrocarbon gas may be used. They may be in a liquid state at room temperature.

The raw material gas may include a component containing silicon such as silane or chlorosilane and a component containing carbon such as hydrocarbon. The silicon-containing component and the carbon-containing component may be the same or different. Since silane gases contain silicon and carbon in a single compound, the silane gases are the preferred source gases that can displace hydrocarbons.

The carrier gas storage part 130 stores a carrier gas, and inert gas or argon gas may be used as the carrier gas. Also, hydrogen gas and argon gas may be used as the carrier gas.

The doping gas storage part 140 stores the doping gas, and the doping gas may be a mixture of nitrogen gas and ammonia gas. The nitrogen gas may have a purity of 99.99% or more and an oxygen content of 5 ppm or less. At this time, the volume ratio of the nitrogen gas to the ammonia gas may be 1: 0.01 to 1.

The carrier gas is supplied to the raw material storage part 120 to bubble the raw material in a liquid state, and a mixed gas of the raw material gas and the carrier gas generated by the bubbling is supplied to the raw material storage part 120 through a dope gas mixed with a nitrogen gas and an ammonia gas And supplied to the reaction chamber 110 together.

A silicon carbide film is formed on the surface of the substrate 10 heated to a constant temperature in the reaction chamber 110 by chemical vapor deposition (CVD).

According to the present invention, the concentration of the source gas introduced into the reaction chamber (the flow rate of the source gas (l / min) / the flow rate of the carrier gas (l / min)) is 5 to 15% by volume and the concentration of the nitrogen gas / Minute) / raw material gas flow rate (l / min)) is set to 10 to 120% by volume and the retention time of the raw material gas is controlled to 7 to 110 seconds. However, the retention time (sec) of the source gas = {(effective reaction volume (l) of reaction chamber / (flow rate of raw material gas (l / min))} {(273 + 20) / (273 + ))} X 60.

As the substrate, it is preferable to use a graphite having impurities of 20 ppm or less, a coefficient of thermal expansion of 3.0 to 4.5 x 10 ^-6 / 캜, and a specific volume of 1.75 to 1.85, and the temperature of the substrate is adjusted to 1300 to 1500 캜.

The film forming rate can be set to 20 to 100 占 퐉 / hour by the combination of the above-described reaction conditions, and the film can be formed by a combination of nitrogen, carbon, silicon (Si (Si ) Is formed on the surface of the base material by a dense and high-purity nitrogen-doped CVD-SiC film having an n-type semiconductor property with an impurity concentration of 150 ppb or less.

If the residence time of the raw material gas is less than 7 seconds, the specific gravity of SiC is lowered to lose the compactness, and it becomes easy to absorb the impurity gas, and the SiC film having the above- Oxidizing property and corrosion resistance are deteriorated. If the retention time exceeds 110 seconds, the film forming speed is slowed.

 When the concentration of the doping gas in which the nitrogen gas and the ammonia gas are mixed is 0 vol.%, The resistivity is increased and the light transmittance is also increased, resulting in a light transmitting property. If the concentration of the doping gas exceeds 10% by volume, the resistivity may be excessively lowered.

 After the film formation, the SiC film on the outer peripheral portion of the substrate graphite is removed by machining or grinding, and the base graphite is removed by air oxidation, machining, grinding or the like to obtain an SiC compact. The obtained SiC compact is subjected to processing as required and finished in a shape and surface suitable for various applications.

The electric resistivity of a silicon carbide (CVD-SiC) shaped body produced by chemical vapor deposition is greatly influenced by a trace amount of impurity concentration contained in the shaped body. Pure CVD-SiC compacts have resistivities in excess of about 50 [Omega] m. When the concentration of impurities increases in the pure CVD-SiC compact, the resistivity of the pure CVD-SiC compact decreases sharply.

Elements such as boron and phosphorus may be added so that the CVD-SiC compact has low resistivity. However, other reactions such as boron and phosphorus are more likely to be affected by the addition of elements such as boron and phosphorus, which complicates the mixing of the elements in the CVD process during the CVD process and causes the formation of CVD-SiC moldings such as thermal conductivity and high temperature stability Causing other characteristics to deteriorate.

When nitrogen is mixed at a constant concentration in the CVD process, deterioration of other characteristics of the CVD-SiC compact can be minimized and the electrical resistivity can be maintained between about 0.01 and 10 Ωm.

Example

Hereinafter, an embodiment of the present invention will be described.

A CVD-SiC compact was produced using the CVD reaction apparatus shown in Fig. In the reaction chamber, six graphite substrates having a diameter of 8 inches and a thickness of 6 mm were provided. The direction of the gas nozzle was adjusted such that the raw material gas did not directly contact the substrate, and the gas contacted the side surface and the upper surface of the reaction chamber and indirectly contacted with the substrate.

Methyltrichlorosilane (MTS) was used as the raw material gas, hydrogen gas was used as the carrier gas, the flow rate of the raw material gas was 200 l / min, and the concentration of the raw material gas was 7.5% by volume. As the doping gas, a mixture of nitrogen gas and ammonia gas is used. At this time, the volume ratio of the nitrogen gas to the ammonia gas is 1: 0.5. The flow rate of the doping gas was varied from 0 to 20 l / min (concentration of doping gas: 0 to 10% by volume), the retention time of the source gas was 36.8 seconds, and the reaction temperature was 1400 캜 for 75 hours. The deposition rate was 56 탆 / hour.

After the reaction, the graphite substrate was removed to obtain a CVD-SiC molded body (test material) having a thickness of 3.5 mm. The obtained SiC formed body was subjected to a purity analysis to observe the uniformity of the film formation on the appearance, to detect the total impurity concentration, to measure the resistivity and the light transmittance according to the following method, and to carry out the heat resistance impact test, the corrosion resistance test and the specific gravity measurement Respectively.

Resistivity Measurement: The SiC compact is planarized to a thickness of 3 mm and then processed to a size of 4 mm x 40 mm, and the intrinsic resistance of the SiC compact is measured.

Measurement of Light Transmittance: The SiC molded body was subjected to planar processing to a thickness of 0.5 mm, and the SiC molded body was subjected to planarization using a magnetic spectrophotometer (UV-3100PC) manufactured by Shimadzu Seisakusho Co., The light transmittance is measured.

Heat shock test: The SiC compact was planarized to a thickness of 3 mm and then processed to a diameter of 250 mm. The SiC compact was maintained in a furnace at 1200 ° C for 500 minutes, , Cooled to 500 deg. C, and re-introduced into the furnace at 1200 deg. C) for 20 times (20 cycles) to examine the number of times that the molded body was cracked.

Corrosion resistance test: The SiC compact was planarized to a thickness of 3 mm and then processed into a size of 4 mm x 40 mm. The SiC compact was dipped in a hydrogen chloride stream (flow rate: 5 l / min) Keeping the time, and calculating the weight change before and after the test.

Example reaction
Temperature
(° C) reaction
time
(h) Raw gas Doping gas SiC compact flux
(l / min) density
(volume%) Residence time
(second) flux
(l / min) density
(volume%) Film thickness
(mm) Deposition rate
(탆 / h) One 1400 75 200 7.5 36.8 0 0 4.2 56 2 1400 75 200 7.5 36.8 One 0.5 4.2 56 3 1400 75 200 7.5 36.8 10 5 4.2 56 4 1400 75 200 7.5 36.8 20 10 4.2 56

Example Appearance observation Total impurities
Concentration (ppb) Resistivity
(Ωm) Light transmittance
(%) Heat resistance
Impact test Corrosion test
(Small amount of weight)
(weight%) importance One Good 143 50 3.5 No crack 1.94 3.10 2 Good 114 0.5 2.5 No crack 1.86 3.15 3 Good 103 0.01 2.3 No crack 1.75 3.20 4 Good 92 0.003 1.05 No crack 1.67 3.20

As a result of the tests of Examples 1 to 4, as shown in Tables 1 and 2, the film was uniform in appearance, and unevenness was not observed. The specific gravity was about 3.10 to 3.20. Purity analysis showed that the total impurity concentration was about 143 ppb or less and was high purity. No cracks were found in the heat shock test, which was good. In the corrosion resistance test, weight loss was less than 1.94 wt%.

However, the resistivity and the light transmittance were different in Examples 1 to 4.

Specifically, in Example 1 in which the flow rate of the doping gas in which the nitrogen gas and the ammonia gas were mixed was 0 (l / min), the resistivity was 50 Ωm and the light transmittance was 0.05%. In Example 2 in which the flow rate of the doping gas was 1 (l / min), the resistivity was 0.5 Ω m and the light transmittance was 2.5%. In Example 3 in which the flow rate of the doping gas was 10 (l / min), the resistivity was 0.01 Ωm and the light transmittance was 2.3%. In Example 4 in which the flow rate of the doping gas was 20 (l / min), the resistivity was 0.003? M and the light transmittance was 1.05%.

As described above, according to the silicon carbide molded body of the present invention and the manufacturing method thereof, the silicon carbide molded body has not only excellent denseness, high purity and other characteristics, but also low resistivity and light transmittance. Therefore, the utilization of the silicon carbide formed body can be enhanced by using the silicon carbide formed body as a substrate for various semiconductor manufacturing apparatuses.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims. It can be understood that it is possible.

100: chemical vapor deposition apparatus 110: reaction chamber
120: source gas storage part 130: carrier gas storage part
140: doping gas storage part 10: substrate

Claims (3)

Wherein the silicon carbide formed body is formed by chemical vapor deposition and has an electrical resistivity of 0.01 to 10 m m. The silicon carbide molded body according to claim 1, further comprising a light transmittance of 2.3 to 2.5% A method for producing a silicon carbide molded body by introducing a nitrogen gas together with a raw material gas and a carrier gas into a reaction chamber to form a silicon carbide film on the surface of the substrate by chemical vapor deposition and then removing the substrate,
(1 / min) / carrier gas flow rate (l / min)) introduced into the reaction chamber in which the chemical vapor deposition process in which the substrate is provided is 7.5% by volume, the nitrogen gas and the ammonia gas Wherein the concentration of the mixed doping gas (nitrogen gas flow rate (l / min) / raw material gas flow rate (l / min)) is 0.5 to 5 vol%.

Images