CN111133128B - Susceptor and MOCVD apparatus including the same - Google Patents
Susceptor and MOCVD apparatus including the same Download PDFInfo
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- CN111133128B CN111133128B CN201880058624.5A CN201880058624A CN111133128B CN 111133128 B CN111133128 B CN 111133128B CN 201880058624 A CN201880058624 A CN 201880058624A CN 111133128 B CN111133128 B CN 111133128B
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/458—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for supporting substrates in the reaction chamber
- C23C16/4581—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for supporting substrates in the reaction chamber characterised by material of construction or surface finish of the means for supporting the substrate
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/06—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of metallic material
- C23C16/18—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of metallic material from metallo-organic compounds
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/458—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for supporting substrates in the reaction chamber
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/458—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for supporting substrates in the reaction chamber
- C23C16/4582—Rigid and flat substrates, e.g. plates or discs
- C23C16/4583—Rigid and flat substrates, e.g. plates or discs the substrate being supported substantially horizontally
- C23C16/4586—Elements in the interior of the support, e.g. electrodes, heating or cooling devices
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
Abstract
The present invention relates to a susceptor for reducing temperature variation on a support surface by a coating layer and an MOCVD apparatus including the same. According to the susceptor of the embodiment of the present invention, the susceptor may have a supporting surface which is in contact with a substrate and supports the substrate, and a side surface which is connected to the supporting surface, and the susceptor may be configured to be heated while supporting the substrate by induction heating by an induction coil. It may be that the base includes: a base material made of a material that can be inductively heated in response to the induction coil; and a coating layer which is applied to a part or the whole of the surface of the base material to form a part or the whole of the supporting surface and has a magnetic property different from that of the base material. According to the susceptor and the MOCVD apparatus including the same of the present invention, it is possible to grow a thin film having more uniform characteristics on a substrate by reducing temperature unevenness on a support surface supporting the substrate, and it is possible to obtain a high yield in element fabrication by using a substrate grown by the MOCVD process. In addition, according to the MOCVD equipment of the present invention, the temperature on the support surface can be measured accurately.
Description
Technical Field
The present invention relates to a susceptor and an MOCVD apparatus including the same, and more particularly, to a susceptor capable of reducing temperature variation on a support surface by a coating layer and measuring a temperature on the support surface accurately, and an MOCVD apparatus including the same.
Background
Chemical Vapor Deposition (CVD) is a technique of forming a thin film by a Vapor phase Chemical reaction by flowing a source gas over a substrate to be coated and applying external energy to decompose the source gas.
In order to normally perform a chemical reaction, it is necessary to precisely control various process conditions and environments, and to supply energy for activation so that a raw material gas spontaneously causes a chemical reaction.
Chemical vapor deposition is classified into LPCVD (Low Pressure CVD) using a Low Pressure of several to several hundreds of mTorr, PECVD (Plasma-Enhanced CVD) using Plasma to activate a source gas, MOCVD (Metal-Organic CVD) using a gas molecule in a form of bonding an Organic reactive group to a Metal element as a source material, and the like.
The MOCVD equipment is an equipment for growing a compound semiconductor crystal by mixing a group III alkyl (organic metal material gas) and a group V material gas with a high-purity carrier gas, supplying the mixture into a reaction chamber, and thermally decomposing the mixture on a heated substrate.
Fig. 1 is a schematic cross-sectional view showing a reactor configuration of a conventional MOCVD apparatus.
Referring to fig. 1, a reactor 10 of a conventional MOCVD apparatus is configured to include: a reaction chamber 1 into which a reaction gas flows and reacts, and then from which the reaction gas flows; a susceptor (susceptor)2 supporting the substrate W in such a manner that the substrate W is exposed to the reaction chamber 1; and a heating mechanism 3 that applies heat to the susceptor 2.
Since the substrate W needs to be heated to a high temperature in order to react the reaction gas on the substrate W, the susceptor 2 may be heated by the heating mechanism 3 of a thermal resistance method or an induction heating method, thereby heating the substrate W.
Among them, a resistance heating type heater using a hot wire of a metal material such as tungsten, rhenium, or the like can be used as the heating mechanism 3, but there is a problem that the life is short under the process conditions in the ultra high temperature region exceeding 1200 ℃, and a temperature unevenness problem may occur depending on the arrangement of the hot wire. Thus, it is not suitable for a large-capacity large-area manufacturing process requiring an ultra-high temperature.
In order to solve such a problem, a heating mechanism of an induction heating type is used as a main heating mechanism in an ultra high temperature apparatus exceeding 1200 ℃. In comparison with a conventional resistance heating type heater, although temperature variation on the supporting surface of the supporting substrate can be reduced by using a heating mechanism of an induction heating type, temperature unevenness still remains on the supporting surface of the substrate.
The deposition rate and crystallinity of a thin film deposited on a substrate are greatly affected by the temperature of the substrate W, and particularly, the temperature uniformity of the support surface of the susceptor 2 on which the substrate W is placed is the largest factor that determines the uniformity of the thin film on the substrate.
In addition, since the trend of device manufacturers to determine the yield of devices is to increase the temperature uniformity requirement as the design rule (design rule) of the device process is reduced recently, the development of an induction heating susceptor with excellent temperature uniformity may be a current issue for the industry.
On the other hand, in order to manufacture a light emitting diode and a laser diode that emit ultraviolet rays, a substance based on aluminum nitride (AlN) is generally used. In order to suppress TMAl used as a precursor of aluminum (precusor) and NH used as a precursor of N3Parasitic reaction of (2), NH is required3Flow of (2) is minimized, in order to grow high quality aluminum nitride, due to NH3Low Cracking (Cracking) efficiency, requires growth at high temperatures above 1400 ℃. In order to achieve such a temperature, a method of arranging a heat resistance type heater on the periphery of the susceptor or heating the graphite material itself by induction heating is generally used.
However, in a high temperature region of 1400 ℃ or higher, the RF induction heating system is mainly used due to the durability problem of the aforementioned thermal resistance system heater.
As such an RF induction heating method, there are a flat (cascade) method in which an induction coil is disposed under a susceptor and a cascade (cascade) method in which an induction coil is disposed so as to wrap a side surface of a susceptor. The flat type is generally mainly a circular plate-shaped susceptor, and the cascade type is generally mainly a cylindrical susceptor.
In terms of thermal efficiency, it is advantageous to use a cylindrical susceptor for the induction coil of the cascade method.
However, in the case of using the induction coil of the cascade system, when a cylindrical susceptor having a diameter of 100mm or more is used due to imbalance of induced currents inside the susceptor, there is a problem in that the temperature of the central portion of the upper surface of the susceptor is significantly lower than that of the edge portion.
Namely, there are the following problems: the imbalance of the induced current causes temperature unevenness on the susceptor, which spreads to temperature unevenness of the substrate placed on the susceptor supporting surface, resulting in a decrease in characteristic uniformity and a decrease in yield, thereby having a problem of high manufacturing cost.
(patent document 1)
Korean patent No. 10-0676404 (temperature elevation control method for semiconductor substrate and apparatus therefor)
Disclosure of Invention
The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a susceptor that can reduce temperature variations on a support surface by a coating layer and can measure a temperature on the support surface accurately, and an MOCVD apparatus including the susceptor.
The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following descriptions.
The susceptor according to an embodiment of the present invention for solving the above-described problems may include a support surface that is in contact with a substrate and supports the substrate, and a side surface that is connected to the support surface, and the susceptor may be configured to be heated while supporting the substrate by induction heating by an induction coil. It may be that the base includes: a base material made of a material that can be inductively heated in response to the induction coil; and a coating layer which is applied to a part or the whole of the surface of the base material to form a part or the whole of the supporting surface and has a magnetic property different from that of the base material.
According to another feature of the present invention, the induction coil may be arranged to surround the side face.
According to still another feature of the present invention, the base material may have any one of diamagnetic properties and paramagnetic properties, and the coating layer may have magnetic properties different from those of the base material.
According to still another feature of the present invention, the base material may be made of graphite, and the coating layer may include tantalum carbide.
According to still another feature of the present invention, the tantalum carbide may be TaCxAnd x is greater than 0.9.
According to still another feature of the present invention, the coating layer may be a first coating layer, and the susceptor may further include a second coating layer made of Silicon Carbide (Silicon Carbide), the first coating layer being formed to cover a portion of the base material, the second coating layer being formed to cover at least a surface of the base material that is not coated with the first coating layer.
According to still another feature of the present invention, the first coating layer may be located at an edge portion of the supporting surface, and the second coating layer may be located at a central portion of the supporting surface.
According to another embodiment of the susceptor for solving the above-described problems, the susceptor may include a support surface that is in contact with a substrate and supports the substrate, and a side surface that is connected to the support surface, and the susceptor may be configured to be heated while supporting the substrate by induction heating using an induction coil arranged so as to surround the side surface. It may be that the base includes: a base material made of a material that can be inductively heated in response to the induction coil; and a coating layer formed on at least a part of the base material and containing tantalum carbide, wherein a part or the whole of the bearing surface is formed by the coating layer.
According to still another feature of the present invention, the width of the support surface may be 100mm or more.
According to still another feature of the present invention, a ratio of a width of the support surface to a height of the base may be 5 or less.
The MOCVD apparatus according to an embodiment of the present invention for solving the above problems may include: a reaction chamber; a susceptor having a support surface that is in contact with the substrate so as to expose the substrate to the reaction chamber and supports the substrate, and a side surface connected to the support surface; and an induction coil arranged to surround the side surface to inductively heat the susceptor, the susceptor being the susceptor described above.
According to another feature of the invention, the MOCVD equipment further comprises: a temperature measuring module for measuring the temperature of the upper surface of the support surface having the base; and an emissivity measuring module for measuring emissivity of the bottom surface of the susceptor. The MOCVD apparatus is configured to calculate a temperature on the support surface based on data obtained by the temperature measurement module and the emissivity measurement module.
According to still another feature of the present invention, the temperature measurement module receives light through a lens, and the emissivity measurement module receives light through a light pipe (light pipe).
According to the susceptor and the MOCVD apparatus including the same of the present invention, it is possible to grow a thin film having more uniform characteristics on a substrate by reducing temperature unevenness on a support surface supporting the substrate, and it is possible to obtain a high yield in element fabrication by using a substrate grown by the MOCVD process. In addition, according to the MOCVD equipment of the present invention, the temperature on the support surface can be measured accurately.
Drawings
Fig. 1 is a schematic cross-sectional view showing a reactor configuration of a conventional MOCVD apparatus.
Fig. 2 is a sectional view schematically showing a state in which a susceptor according to an embodiment of the present invention is mounted on a reactor of an MOCVD apparatus.
Fig. 3 is a sectional view schematically showing the base of fig. 2.
Fig. 4 is magnetic flow simulation data of the base material inductively heated in a state where the coating layer is not formed.
Fig. 5 is temperature distribution simulation data of the base material induction-heated in a state where the coating layer is not formed.
Fig. 6 shows actually measured temperature distribution data on the supporting surface of the susceptor whose coating layer is made of silicon carbide.
FIG. 7 shows temperature distribution data on the support surface of the susceptor whose coating layer is made of tantalum carbide, which was actually measured.
Fig. 8 is a graph showing characteristics of peak wavelengths of UV C multiple quantum well structure wafers grown using a susceptor coated with silicon carbide.
Fig. 9 is a graph showing characteristics of peak wavelengths of UV C multiple quantum well structure wafers grown using a susceptor coated with tantalum carbide.
Fig. 10 is a schematic cross-sectional view of a base according to another embodiment.
Fig. 11 is a schematic cross-sectional view of a base according to yet another embodiment.
Fig. 12 is a schematic top view showing an exemplary planar arrangement of the first coating layer and the second coating layer.
Fig. 13 is a sectional view schematically showing an MOCVD apparatus having a configuration for measuring the susceptor temperature according to the present invention.
FIG. 14 shows a graph of the temperature measured by a thermocouple for SiC coated pedestals and TaC coated pedestals versus the temperature measured by a lens-illuminated pyrometer at a fixed emissivity.
Detailed Description
The advantages, features and methods of accomplishing the same of the present invention will become apparent by reference to the following detailed description of the embodiments when taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms different from each other, and the embodiments are provided only for the purpose of making the disclosure of the present invention complete, and providing those skilled in the art with a full understanding of the scope of the present invention, which is defined only by the scope of the claims.
Although the terms first, second, etc. are used for describing various constituent elements, it is apparent that these constituent elements are not limited to these terms. These terms are used only for distinguishing one constituent element from another constituent element. Therefore, it is obvious that the first constituent element mentioned below may be the second constituent element within the technical idea of the present invention. Meanwhile, even if it is described that the second coating is performed after the first coating, it is obvious that the coating is performed in the reverse order to the first coating and is included in the technical idea of the present invention.
In the present specification, the same reference numerals are used as far as possible when the same components are represented by the same reference numerals even when the drawings are different.
The dimensions and thicknesses of the respective constituents appearing in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the dimensions and thicknesses of the constituents shown.
Hereinafter, embodiments of the base of the present invention will be described with reference to the accompanying drawings.
Fig. 2 is a sectional view schematically showing a state in which a susceptor according to an embodiment of the present invention is mounted on a reactor of an MOCVD apparatus.
First, referring to fig. 2, an arrangement manner and a heating manner of the susceptor 120 in the reactor 100 of the MOCVD apparatus according to an embodiment of the present invention are explained.
Referring to fig. 2, the reactor 100 of the MOCVD apparatus includes: a reaction chamber 110, a susceptor 120, and an induction coil 130.
The reaction chamber 110 includes: an inflow portion 111 into which a gas to be reacted on the surface of the substrate flows; and an outflow portion 112 for allowing residual gas remaining after completion of the reaction (crystal growth) to flow out, and a reaction space S is formed between the inflow portion 111 and the outflow portion 112.
In the present embodiment, the directions and arrangement of the inflow portion 111 and the outflow portion 112 of the reaction chamber 110 are exemplary, and the reaction chamber 110 may also be configured such that the reaction gas flows in the up-down direction or other directions.
The susceptor 120 is configured to have a support surface 121 that supports the substrate W while contacting the substrate W so as to expose the substrate W to the reaction space S of the reaction chamber 110, and a side surface 122 connected to the support surface 121. In other words, it can be said that the base 120 has a substantially cylindrical shape.
On the other hand, a hole 123 for inserting a thermocouple for temperature measurement may be formed in the susceptor 120.
The susceptor 120 is made of a material capable of induction heating. The base 120 may be composed of a base material and a coating layer, and a specific configuration will be described later with reference to fig. 3.
The induction coil 130 is disposed to surround the side 122 of the susceptor 120 for induction heating of the susceptor 120. The induction coil 130 is configured to be able to apply a current having a frequency of several to several tens kHz, thereby being able to inductively heat the susceptor 120 located inside the induction coil 130.
A thermal blocking film 141 blocking heat of the heated susceptor 120 may be disposed between the induction coil 130 and the susceptor 120. In addition, a heat shielding film 142 blocking radiant heat generated from the heated substrate W may be provided in the reaction chamber 110.
Fig. 3 is a sectional view schematically showing the base of fig. 2.
Referring to fig. 3, the structure of the base 120 will be described in more detail. Referring to fig. 3, the susceptor 120 includes a base material 124 and a coating layer 125. For reference, the thickness of the coating 125 is thin, but is shown to be relatively thicker than the original thickness for ease of illustration.
The base material 124 is made of a material that can be inductively heated by the induction coil 130. On the other hand, since the ferromagnetic material generally has a low melting point, the base material 124 of the susceptor 120 preferably has either diamagnetic or paramagnetic properties for ultrahigh-temperature heat generation.
When the base material 124 is made of a diamagnetic material, carbon (graphite), copper, gold, silver, or the like can be used as a material of the base material 124, and the material should be selected according to a heating temperature range. In the MOCVD-apparatus susceptor 120, graphite (graphite) having a high melting point is preferably selected as a material of the base material 124 in consideration of a high heating temperature.
When the base material 124 is made of paramagnetic material, aluminum, platinum, palladium, stainless steel, etc. can be used as the material of the base material 124, and the material should be selected according to the heating temperature range.
The coating layer 125 covers at least a part of the base material 124, and prevents the base material 124 from reacting with the reaction gas. It is preferable that the coating layer 125 has a magnetic property different from that of the base material 124. For example, when the base material 124 is a diamagnetic body, the coating layer 125 may be made of a paramagnetic body, and conversely, when the base material 124 is a paramagnetic body, the coating layer 125 may be made of a diamagnetic body.
Next, a change in temperature uniformity on the bearing surface 121 when the material of the coating 125 is changed is observed with reference to fig. 4 to 9.
Fig. 4 is magnetic flow simulation data of the base material inductively heated in a state where the coating layer is not formed, and fig. 5 is temperature distribution simulation data of the base material inductively heated in a state where the coating layer is not formed. Fig. 6 shows actually measured temperature distribution data on the supporting surface of the susceptor whose coating layer is made of silicon carbide, and fig. 7 shows actually measured temperature distribution data on the supporting surface of the susceptor whose coating layer is made of tantalum carbide. Further, fig. 8 is a graph showing characteristics of peak wavelengths of UV C multiple quantum well structure wafers grown using a susceptor whose coating is formed of silicon carbide, and fig. 9 is a graph showing characteristics of peak wavelengths of UV C multiple quantum well structure wafers grown using a susceptor whose coating is formed of tantalum carbide.
First, referring to fig. 4 and 5, when the base material 124 is inductively heated in a state where the induction coil 130 is wound around the side surface 122 of the base material 124 made of only graphite as shown in fig. 2, the density of the magnetic current is high in the side surface 122 portion, and the density of the magnetic current decreases as it approaches the inside. It is also referred to as the epidermal phenomenon.
As a result, as shown in fig. 5, a temperature distribution is obtained in which high-temperature induction heating occurs near the side surface 122 of the base material 124 and the temperature decreases as the center portion is approached. As a result, the bearing surface 121 obtains a high temperature at the edge portion and a relatively low temperature at the central portion.
Such simulation results show that when the cylindrical susceptor is inductively heated by the induction coil 130 around the side surface thereof, a large temperature deviation occurs at the supporting surface 121. A large temperature deviation at the bearing surface 121, as mentioned above, leads to uneven crystal growth on the substrate W, which has a negative effect on productivity. Based on these results, it is known in the industry that the manner of induction heating using induction coils in the form of a cascade for a susceptor having a diameter of 100mm or more is not suitable.
However, the inventors of the present application have found through experiments that the temperature distribution on the support surface 121 differs depending on the material of the coating 125. Fig. 6 and 7 show results measured by experiments.
FIG. 6 shows data obtained by measuring the temperature on the support surface 121 by induction heating a susceptor having a coating layer 125 of silicon carbide (SiC) at a frequency of 10 to 20 kHz.
Referring to fig. 6, the trend is consistent with the simulation data of fig. 5, and a high temperature tends to be formed at the edge of the support surface 121 and a low temperature tends to be formed at the center. The temperature deviation in the entire 38mm distance area d was measured to be 18 ℃.
On the other hand, fig. 7 shows data obtained by measuring the temperature on the support surface 121 by induction heating the susceptor having the coating layer 125 formed of tantalum carbide (TaC) at a frequency of 10 to 20 kHz. That is, only the material of the coating 125 is changed under the same other conditions.
Referring to fig. 7, unlike fig. 6, it is measured that the temperature of the edge of the support surface 121 is lower than that of the central portion. Thus, the temperature deviation was also measured to be 5 ℃ in the 38mm distance region d, which is relatively low compared to the results of fig. 6.
That is, the temperature variation when the coating layer 125 is formed of tantalum carbide is measured to be smaller than the temperature variation when formed of silicon carbide.
Referring to fig. 8 and 9, Al is grown using the susceptor coated with silicon carbide and the susceptor coated with tantalum carbidexGa1-xN/AlyGa1-yN(0<x<1，0<y<1) The photoluminescence measurement was performed on the wafers having the multiple quantum well structure, and the difference of the susceptor coated with tantalum carbide was confirmed again from the measured peak wavelength distribution result.
Referring to fig. 8, in the susceptor in which the coating 125 is formed of silicon carbide (SiC), it was confirmed that the peak wavelength of the wafer region at the edge portion is shorter than that at the center portion of the supporting surface 121. This phenomenon occurs because the higher the temperature in the high temperature region of about 1200 ℃, the higher the mixing speed of aluminum is than the mixing speed of gallium, so the aluminum composition in the edge portion is higher than that in the center portion, which shows an increase in band gap, and finally shows a peak wavelength. That is, it can be judged that it is a result of directly reflecting the temperature unevenness of the surface of the bearing surface 121.
In contrast, referring to fig. 9, in the susceptor in which the coating layer 125 is formed of tantalum carbide (TaC), it was confirmed that the peak wavelength of the wafer region disposed in the central portion is shorter than that of the edge portion of the supporting surface 121. By this photoluminescence measurement, a temperature gradient phenomenon on the susceptor based on the material of the coating layer was also confirmed.
It is presumed that this increase in temperature uniformity across the bearing surface 121 is due to: 1) the difference in magnetic properties of the parent material 124 and the coating 125; 2) based on the emissivity difference of the material of the coating 125.
First, it is predicted that the tendency of magnetic flux to occur inside the coating layer 125 when the magnetic characteristics of the coating layer 125 are the same as the base material 124 is also similar to the base material 124, and thus the thermal distribution is also predicted to be similar. That is, when the material of the base material 124 is graphite which is a diamagnetic substance, it is predicted that the coating layer 125 formed of silicon carbide which is a similar diamagnetic substance does not exert a large influence on the temperature distribution formed only by the base material 124, and the simulated temperature distribution tendency of fig. 5 is actually observed in fig. 6.
On the other hand, tantalum carbide is a binary chemical compound (binary chemical compounds) of tantalum and carbon, and TaC is used for the experimental formulaxAnd (4) showing. Where x generally has a value of 0.4 to 1, the magnetic properties of tantalum carbide vary depending on the value of x. Namely, TaC is knownxDiamagnetic when x is less than 0.9 and paramagnetic when x exceeds 0.9.
Wherein if TaCxWhen x of (2) is 0.9 or less, tantalum carbide has diamagnetic properties as in the case of graphite of the base material, and therefore, it is estimated that the coating layer 125 is formed of silicon carbide and does not largely affect temperature variation.
However, it is considered that TaC is observed when x exceeds 0.9xIn the case of paramagnetism, magnetic flux in a direction opposite to the magnetic flux in the diamagnetic base material 124 is formed inside the coating layer 125, thereby obstructing the base material124, the magnetic flux forms on the surface. That is, it is considered that heat generated from the surface of the base material 124 is offset by the tantalum carbide coating layer, and heat generated from the inside is conducted to the inside to heat the supporting surface 121, so that a more uniform temperature distribution on the supporting surface 121 can be obtained.
Further, since the emissivity of tantalum carbide is considerably lower than the emissivity of silicon carbide, about 1/3, it is considered that, in the case of the coating layer 125 made of tantalum carbide, heat generated in the base material 124 is less likely to be thermally conducted to the support surface 121 side, and thus a more uniform temperature distribution can be obtained on the support surface 121.
That is, when the base material 124 is made of graphite, which is a diamagnetic material, tantalum carbide (TaC), which is a paramagnetic material, passes throughxWhere x exceeds 0.9) is formed, temperature unevenness on the bearing surface 121 can be reduced by the magnetic flux acting against the surface of the base material 124 and the low emissivity of the coating layer 125.
Fig. 10 is a schematic cross-sectional view of a base according to another embodiment.
Referring to fig. 10, the base 120' of the present embodiment is formed by overlapping coatings 125, 126 different from each other. The parent material 124 is illustrated as being made of graphite, the first coating layer 125 is illustrated as being made of tantalum carbide, and the second coating layer 126 is illustrated as being made of silicon carbide.
The first coating layer 125 is formed to cover a portion of the base material 124. In particular, it is preferable that the first coating layer 125 is disposed between the edge portion of the support surface 121 where the temperature of the parent material 124 is relatively high and the parent material 124. Due to this arrangement of the first coating 125, heat of the relatively high-temperature edge portion can be dispersed to the central portion.
The second coating 126 is disposed on the portion of the first coating 125 that is not covered. That is, the second coating layer 126 is located at least between the central portion of the bearing surface 121 and the base material 124. On the other hand, in the present embodiment, the second coating layer 126 is illustrated to cover the first coating layer 125, but the first coating layer 125 may be exposed to the outside to directly form the support surface 121.
The coating layer 125 may be configured to cover the entire base material 124 as shown in fig. 3, but may be configured to partially cover only a portion having a relatively high temperature as shown in fig. 10. With the configuration as shown in fig. 10, the heat generated in the side surface portion is promoted to flow to the second coat layer 126 having a higher emissivity than the first coat layer 125 having a lower emissivity, and the heat can be distributed more smoothly. This can reduce temperature variation on the support surface 121.
Fig. 11 is a schematic cross-sectional view of a base according to yet another embodiment.
Unlike the base 120' of fig. 10, the base 120 ″ of the present embodiment illustrates that the second coating layer 126 covers only a portion of the first coating layer 125 to expose the first coating layer 125 to the outside.
As such, the second coating layer 126 does not cover the entirety of the first coating layer 125, so that the first coating layer 125 is directly exposed to the outside.
The arrangement of such a coating layer can be appropriately selected by experiments according to the shape of the base material 124 itself, the condition of induction heating, the material of the base material 124, and the like.
Fig. 12 is a schematic top view showing an exemplary planar arrangement of the first coating layer and the second coating layer.
Referring to fig. 12, the first coating 125 and the second coating 126 may form the bearing surface 121 in a manner that constitutes various planar arrangements.
For example, as shown in fig. 12 (a), the first coating layer 125 and the second coating layer 126 may be sequentially arranged in concentric circles, and as shown in fig. 12 (b), the first coating layer 125 and the second coating layer 126 may be formed in a spirally wound manner.
On the other hand, when the coating layers 125 and 126 are formed as shown in fig. 12 (a), the plurality of first coating layers 125 and the plurality of second coating layers 126 are not continuous, and thus, it may be necessary to perform a plurality of coating operations, but since the first coating layers 125 and the second coating layers 126 are continuous as shown in fig. 12 (b), the support surface 121 can be formed by only one coating operation.
As such, the planar arrangement of the first coating 125 and the second coating 126 may be formed in a variety of forms.
On the other hand, in the susceptor 120 described with reference to fig. 3, the base material 124 and the coating layer 125 are different from each other in magnetic properties, but even if they are the same as each other, when the coating layer 125 is formed of tantalum carbide, temperature variation on the bearing surface 121 can be reduced due to the low emissivity of tantalum carbide.
That is, even if a part or the whole of the support surface 121 of the cylindrical susceptor is formed of the coating layer 125 including tantalum carbide regardless of the magnetism of the base material 124, the heat of the side surface 122 portion can be concentrated and dispersed to the central portion of the support surface 121 due to the low emissivity of the coating layer 125, and at the same time, the radiation heat emission over a wide range can be suppressed to improve the temperature uniformity.
This effect is particularly evident in cylindrical susceptors heated by induction coils arranged in a manner surrounding the side surface 122. That is, the above-described coating structure is preferably applied to a susceptor having a height relatively larger than the width and length of the support surface 121. More specifically, the ratio of the width of the support surface 121 to the height of the base is preferably 5 or less.
On the other hand, in view of productivity, the width of the support surface 121 is preferably 100mm or more, and in order to maintain the ratio of the width of the support surface 121 to the height of the susceptor, the height of the susceptor is preferably 50mm or more.
Fig. 13 is a sectional view schematically showing an MOCVD apparatus having a configuration for measuring the susceptor temperature according to the present invention.
The MOCVD apparatus 100' according to an embodiment of the present invention includes a susceptor 120, wherein the susceptor 120 includes the TaC coating described above. Since the base 120 is configured as described above, detailed description thereof is omitted. Obviously, the above-described configurations of the base 120' and the base 120 ″ may be applied to the base 120.
The induction coil 130 is disposed at a side 122 portion of the susceptor 120 to heat the susceptor 120. At this time, in order to measure the temperature of the upper surface of the susceptor 120 on which the wafer is positioned, the noncontact temperature measuring module 150 is disposed on the upper side of the susceptor 120. As the temperature measuring module 150, a lens light-receiving type pyrometer (pyrometer) can be used. The pyrometer used as the temperature measurement module 150 is adapted to use a lens to non-contact collect radiant energy radiated from the base 120 in the optical system.
On the other hand, in order to calculate the temperature of the upper surface of the susceptor 120 using the radiant energy measured by the temperature measuring module 150, it is necessary to specify the emissivity (epsilon), and in order to measure the accurate emissivity, the MOCVD device 100' further includes an emissivity measuring module 160.
As the emissivity measuring module 160, a pyrometer using a light pipe (light pipe) can be used. It is generally preferable that the emissivity measuring module 160 is disposed in the vicinity of the temperature measuring module 150 for measuring the radiant energy, but the light guide tube is easily contaminated due to the coating effect caused by the decomposition of the process gas above the susceptor 120, and thus it is difficult to dispose the light guide tube above the susceptor 120. In this regard, in the present embodiment, the emissivity measuring module 160 is disposed to face the bottom surface of the susceptor 120 to measure the emissivity of the bottom surface of the susceptor 120.
As described in more detail later, the emissivity measuring module 160 can calculate an accurate temperature without being located near the temperature measuring module 150.
FIG. 14 shows a graph of the temperature measured by a thermocouple for SiC coated pedestals and TaC coated pedestals versus the temperature measured by a lens-illuminated pyrometer at a fixed emissivity.
Referring to fig. 14, in the conventional susceptor coated with SiC, as the temperature (x-axis) measured by the thermocouple increases, the temperature (y-axis) measured by the lens light-receiving type pyrometer increases to some extent, thereby exhibiting a straight line graph form. From this, it can be understood that the susceptor coated with SiC has emissivity which hardly changes with temperature change.
In contrast, in the susceptor coated with TaC, the temperature measured by the lens light-receiving type pyrometer increased with the increase rate decreasing as the temperature measured by the thermocouple increased. That is, it was found that the emissivity of the TaC-coated susceptor changed greatly with temperature.
In addition, as shown in table 1 below, it can be confirmed from the conventional reference that TaC has a large variation in emissivity depending on temperature.
[ Table 1]
Thus, it is known that the emissivity of the susceptor formed by TaC coating greatly varies depending on the coating production method, thickness, and the like.
Therefore, the susceptor 120, 120', 120 ″ according to the above embodiment of the present invention is not capable of measuring a reliable temperature by measuring the temperature on the upper surface of the susceptor 120 only by the temperature measuring module 150 such as a lens light receiving type pyrometer, and is capable of measuring the emissivity in real time by the emissivity measuring module 160 such as a light pipe pyrometer and reflecting the emissivity in the light-temperature conversion calculation formula, thereby obtaining an accurate temperature.
On the other hand, even if the emissivity of the susceptor 120, 120', 120 ″ cannot be measured in real time, the emissivity measuring module 160 may measure the emissivity at each temperature in advance, create an emissivity table based on the temperature in advance, and reflect the emissivity in the light-temperature conversion calculation formula.
In addition, in the case of the conventional flat (pancake) method, the susceptor is heated from the bottom surface, and thus the temperature difference of the upper surface and the bottom surface of the susceptor including the supporting surface is large, but in the case of the susceptor 120, 120 ', 120 ″ of the present invention, the temperatures of the upper surface and the bottom surface of the susceptor 120, 120 ', 120 ″ are approximated by simultaneously heating the upper surface and the bottom surface of the susceptor 120, 120 ', 120 ″ by using the cascade method. Therefore, there is an advantage that it is possible to adapt the emissivity above the base 120, 120 ', 120 ″ that is difficult to measure above by measuring the bottom surface of the base 120, 120', 120 ″.
In addition, as shown in fig. 5, it was confirmed through simulation that the susceptors 120, 120', 120 ″ have temperatures corresponding to the upper and lower surfaces by induction heating at the side surfaces. That is, it is considered that the temperature measured at the bottom surface is almost similar to the temperature measured at the corresponding upper surface, and therefore the emissivity measurement value at the bottom surface can be used for temperature correction at the upper surface.
On the other hand, for more accurate measurement, it is preferable that the conditions of the upper surface and the bottom surface be adjusted to be the same. For example, since emissivity is affected by surface roughness, it is necessary to adjust the surface roughness at the upper and bottom surfaces to be almost the same. Further, a more accurate temperature can be measured by adjusting the factors affecting the emissivity to be the same on the upper surface and the bottom surface. Although fig. 3 illustrates that the coating 125 is not formed on the bottom surface of the susceptor 120, when the emissivity measurement module 160 is used, the coating 125 is preferably formed on the bottom surface under the same conditions as the support surface 121. Which is also the same in the bases 120', 120 ″ of fig. 10 and 11.
Therefore, the accurate temperature at the upper surface of the susceptor 120 can be obtained in real time from the data obtained by the temperature measuring module 150 such as a lens light-receiving pyrometer and the light-pipe light-receiving emissivity measuring module 160.
Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those having ordinary skill in the art to which the present invention pertains will appreciate that the embodiments can be embodied in other specific forms without changing the technical idea or essential features thereof. The embodiments described above are therefore to be understood as illustrative in all respects and not restrictive.
Claims (11)
1. A susceptor having a support surface that supports a substrate while being in contact with the substrate and a side surface that is connected to the support surface, the susceptor being configured to be heated while being supported by the substrate by induction heating by an induction coil,
the base includes:
a base material made of a material that can be inductively heated in response to the induction coil; and
a coating layer which is coated on a part or the whole surface of the base material to form a part or the whole of the supporting surface and has magnetism different from that of the base material,
the parent material has either diamagnetism or paramagnetism,
the coating has the further property of magnetism,
the coating comprises tantalum carbide, the tantalum carbide being TaCxWhen the parent material is diamagnetic, x is greater than 0.9, and when the parent material is paramagnetic, x is less than 0.9.
2. The susceptor of claim 1, wherein,
the induction coil is arranged to surround the side face.
3. The susceptor of claim 1, wherein,
the parent material is made of graphite.
4. The susceptor of claim 2, wherein,
the coating is a first coating and the coating is a second coating,
the susceptor also includes a second coating made of silicon carbide,
the first coating layer is formed to cover a portion of the base material,
the second coating layer is formed to cover at least a surface of the base material that is not coated with the first coating layer.
5. The susceptor of claim 4, wherein,
the first coating layer is located at an edge portion of the support surface,
the second coating is located in a central portion of the bearing surface.
6. A susceptor having a supporting surface that supports a substrate while being in contact with the substrate and a side surface connected to the supporting surface, the susceptor being configured to be heated while supporting the substrate by induction heating by an induction coil arranged so as to surround the side surface,
the base includes:
a base material made of a material that can be inductively heated in response to the induction coil; and
a coating layer which is formed by coating on at least a part of the base material and contains tantalum carbide,
a part or the whole of the bearing surface is formed by the coating,
the tantalum carbide is TaCxWhen the parent material is diamagnetic, x is greater than 0.9, and when the parent material is paramagnetic, x is less than 0.9.
7. The susceptor of claim 1 or 6, wherein,
the width of the support surface is 100mm or more.
8. The susceptor of claim 1 or 6, wherein,
the ratio of the width of the support surface to the height of the base is 5 or less.
9. An MOCVD apparatus, comprising:
a reaction chamber;
a susceptor having a support surface that is in contact with the substrate so as to expose the substrate to the reaction chamber and supports the substrate, and a side surface connected to the support surface; and
an induction coil arranged to surround the side surface to inductively heat the susceptor,
the susceptor is according to any one of claims 1 and 6.
10. The MOCVD apparatus according to claim 9,
the MOCVD apparatus further comprises:
a temperature measuring module for measuring the temperature of the upper surface of the support surface having the base; and
an emissivity measuring module for measuring emissivity of the bottom surface of the susceptor,
the MOCVD apparatus is configured to calculate a temperature on the support surface based on data obtained by the temperature measurement module and the emissivity measurement module.
11. The MOCVD apparatus according to claim 10,
the temperature survey module passes through lens and receives light, the radiance survey module passes through the light pipe and receives light.
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| KR20170122061 | 2017-09-21 | ||
| KR10-2017-0122061 | 2017-09-21 | ||
| KR10-2018-0109824 | 2018-09-13 | ||
| KR1020180109824A KR102205613B1 (en) | 2017-09-21 | 2018-09-13 | Susceptor and mocvd apparatus using the same |
| PCT/KR2018/011297 WO2019059728A2 (en) | 2017-09-21 | 2018-09-21 | Susceptor and mocvd device comprising same |
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| CN111133128A CN111133128A (en) | 2020-05-08 |
| CN111133128B true CN111133128B (en) | 2022-04-12 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006012951A (en) * | 2004-06-23 | 2006-01-12 | Sharp Corp | Vapor phase growth system |
| JP2006070342A (en) * | 2004-09-03 | 2006-03-16 | Sumitomo Electric Ind Ltd | Vapor phase film deposition system, susceptor and vapor phase film deposition method |
| JP2009147170A (en) * | 2007-12-14 | 2009-07-02 | Panasonic Corp | Method and device for manufacturing semiconductor device |
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| JP5228583B2 (en) * | 2008-04-04 | 2013-07-03 | 住友電気工業株式会社 | Susceptor and vapor phase growth apparatus |
| JP6562546B2 (en) * | 2015-07-14 | 2019-08-21 | 昭和電工株式会社 | Wafer support, wafer support, chemical vapor deposition equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006012951A (en) * | 2004-06-23 | 2006-01-12 | Sharp Corp | Vapor phase growth system |
| JP2006070342A (en) * | 2004-09-03 | 2006-03-16 | Sumitomo Electric Ind Ltd | Vapor phase film deposition system, susceptor and vapor phase film deposition method |
| JP2009147170A (en) * | 2007-12-14 | 2009-07-02 | Panasonic Corp | Method and device for manufacturing semiconductor device |
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