JP4505072B2 - Chemical vapor deposition method and chemical vapor deposition apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chemical vapor deposition apparatus that performs chemical vapor deposition using a heating element maintained at a predetermined high temperature.
[0002]
[Prior art]
In the manufacture of various semiconductor devices such as LSI (Large Scale Integrated Circuit) and LCD (Liquid Crystal Display), there is a process of creating a predetermined thin film on a substrate. Among these, since a thin film having a predetermined composition can be formed relatively easily, film formation by a chemical vapor deposition (CVD) method has been often used.
The CVD method is a plasma CVD method in which plasma is generated and a gas phase reaction is caused by plasma energy to form a film, or a substrate is heated and a gas phase reaction is caused by the heat of the substrate to form a film. In addition to the CVD method and the like, there is a type of CVD method (hereinafter referred to as a heating element CVD method) in which a source gas is supplied via a heating element maintained at a predetermined high temperature.
[0003]
A chemical vapor deposition apparatus that performs a heating element CVD method arranges a substrate in a processing container and introduces a source gas while maintaining the heating element provided in the processing container at a predetermined high temperature. When the introduced source gas passes through the surface of the heating element, changes such as decomposition and activation occur in the source gas, and the product resulting from this change reaches the substrate, so that the thin film of the material that is the final target material Is deposited on the surface of the substrate. Of these heating element CVDs, those using wire-like heating elements may be called hot wire (Hot Wire) CVD.
[0004]
When the source gas reaches the substrate through such a heating element, there is an advantage that the temperature of the substrate can be lowered as compared with the thermal CVD method in which a reaction is caused only by the heat of the substrate. Further, since plasma is not formed unlike the plasma CVD method, there is no concern from the problem of damage to the substrate due to plasma. For this reason, the above-mentioned heating element CVD method is regarded as promising for the production of next-generation semiconductor devices that are becoming increasingly highly integrated and highly functional.
[0005]
[Problems to be solved by the invention]
However, according to the inventor's research, it has been found that in the heating element CVD method, impurities that cannot be considered in the normal thermal CVD method or plasma CVD method are mixed in the film. FIG. 6 is a diagram showing the result of an experiment confirming this problem. The result of analyzing a silicon nitride film prepared by an experimental chemical vapor deposition apparatus by secondary ion mass spectrometry (SIMS) is shown. FIG. As the substrate, a gallium arsenide substrate was used.
[0006]
The horizontal axis in FIG. 6 indicates the position in the thickness direction of the substrate. Further, the vertical axis on the right side of FIG. 6 indicates the number of incident secondary ions (count / second) per unit time from the current that flows when the secondary ions enter the detector, and the vertical axis on the left side indicates The concentration of each element (number of elements per unit volume, atoms / cc) calculated quantitatively from the number of secondary ions is shown. The concentration of each element is quantified by comparing with the data on the number of secondary ions obtained using a standard sample.
[0007]
In FIG. 6, Si is detected at a concentration of 10 ¹⁸ or more per square centimeter from the surface of the substrate (the zero point on the horizontal axis) to a position of about 2000 angstroms, with a thickness of about 2000 angstroms from the surface. It is determined that a silicon nitride film has been formed. Then, secondary ion currents corresponding to Fe, Ni, W, and Mn are measured in the region of 0 to 2000 angstroms. When converted from the number of secondary ions, on average, Fe is about 5 × 10 ¹⁷ atoms / cc, Ni is about 1 × 10 ¹⁷ atoms / cc, W is about 1 × 10 ¹⁶ atoms / cc, and Mn is 1 × 10. It is assumed that it is mixed at a concentration of about ¹⁵ atoms / cc. However, the SIMS device used for this analysis has a detection limit of about 5 × 10 ¹⁵ atoms / cc due to the SN ratio of the detection system, and W and Mn are really mixed at this level. It is unknown whether there is.
[0008]
In any case, it was confirmed from the data shown in FIG. 6 that Fe and Ni were mixed at a high concentration in a thin film prepared using a conventional chemical vapor deposition apparatus. Such mixing of metal elements is a phenomenon that has not been observed in a normal thermal CVD apparatus or plasma CVD apparatus. If there is such a high concentration of an unintended metal element, there is a high possibility that the device characteristics will be impaired. How it is inhibited depends on the type and purpose of the thin film. For example, in the case of a silicon film formed using a mixed gas of silane and hydrogen, the carrier mobility starts to decrease when a metal element of about 10 ¹⁶ atoms / cc is mixed. When it is 10 ¹⁷ atoms / cc or more, significant characteristic inhibition such as device malfunction does not occur due to an extremely low carrier mobility. In addition, when a thin film such as a silicon nitride film is formed as a surface protective film or a surface passivation film after formation of an element, if the above heavy metal impurities are mixed in the film, the dielectric strength voltage is lowered. There is a possibility that the function as an electrical protective film may be hindered.
[0009]
The present invention has been made in order to solve the problem specific to the chemical vapor deposition apparatus that performs the heating element CVD method, that is, the problem of impurity contamination in the thin film, which has been confirmed by the inventors' experiments.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 of the present application exhausts the inside of the processing container to 1 × 10 ⁻⁶ Pa to 1 Pa and introduces a reducing gas or an inert gas into the processing container. while tungsten disposed in the processing vessel, by heating by energizing the wire-like heating element made of molybdenum or tantalum, a first temperature iron or nickel contained as impurities in the heating element evaporates A first step of maintaining at least 5 minutes ;
After the first step, the heating element supplying a predetermined raw material gas arranged inside the process chamber, the said heating element is energized to generate heat lower than the first temperature second temperature In this way , the supplied raw material gas is allowed to pass through the surface of the heating element, and the raw material gas is decomposed and / or activated on the surface of the heating element at the time of passing the raw material gas. A second step of creating a predetermined thin film on the substrate ;
It has the structure of containing .
In order to solve the above problem, the invention according to claim 6 of the present application includes a processing container in which a predetermined process is performed on a substrate,
An exhaust system for exhausting the inside of the processing vessel;
A gas supply system for supplying a predetermined source gas into the processing vessel;
A wire-like heating element made of tungsten, molybdenum or tantalum provided in the processing container so that the supplied source gas passes through the surface;
An energy supply mechanism that gives heat to the heating element so that the source gas decomposes and / or activates when the source gas passes, and heats the heating element;
Gas introduction means for introducing a reducing gas or an inert gas into the processing vessel;
A chemical vapor deposition apparatus comprising a substrate holder for holding a substrate at a position in a processing container where a predetermined thin film is created by decomposition and / or activation of a source gas,
State the energy supply mechanism, which before the creation of the thin film, said by the exhaust system evacuated to 1Pa pressure below than 1 × 10 -6 ^Pa, and was introduced reducing gas or an inert gas by said gas introducing means Then, after the heating element is energized at a first temperature which is a temperature at which iron or nickel contained as impurities in the heating element evaporates for 5 minutes or more to generate heat, the raw material gas is produced during the formation of the thin film. The heat generating element is energized to generate heat so that the second temperature lower than the first temperature is generated and decomposed and / or activated .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
FIG. 1 is a front view showing a schematic configuration of a chemical vapor deposition apparatus according to an embodiment of the present invention. The apparatus shown in FIG. 1 includes a processing container 1 in which a predetermined process is performed on a substrate, a gas supply system 2 for supplying a predetermined raw material gas into the processing container 1, and the supplied raw material gas on the surface. A heating element 3 provided in the processing container 1 so as to pass through, an energy supply mechanism 30 that gives energy to the heating element 3 so that the heating element 3 is maintained at a predetermined high temperature, and a heat generation maintained at a predetermined high temperature A substrate holder 4 for holding the substrate 9 at a predetermined position in the processing container 1 where a predetermined thin film is formed by decomposition and / or activation of the source gas on the surface of the body 3 is provided.
[0012]
The processing container 1 is an airtight container including an exhaust system 11 and includes a gate valve (not shown) for taking in and out the substrate 9. Note that a load lock chamber (not shown) is airtightly connected to the processing container 1 via a gate valve. The processing container 1 is made of a material such as stainless steel or aluminum and is electrically grounded.
Exhaust system 11 includes a vacuum pump such as a turbo molecular pump, the inside of the process chamber 1 1 × 10 ^- is evacuable configured below ⁴ Pa. The exhaust system 11 includes an exhaust speed adjuster (not shown).
[0013]
The gas supply system 2 includes a gas cylinder 21 in which a predetermined raw material gas is stored, a gas supply device 22 provided in the processing container 1, a pipe 23 connecting the gas cylinder 21 and the gas supply apparatus 22, and a pipe 23. The valve 24 and the flow rate regulator 25 are configured.
The gas supply unit 22 is a hollow member and has a front surface facing the substrate holder 4. A large number of small gas blowing holes 220 are formed on the front surface. A gas is introduced from the gas cylinder 21 through the pipe 23 into the gas supply device 22, and this gas is blown out from the gas blowing hole 220 and supplied into the processing container 1.
[0014]
The substrate holder 4 is a member provided so as to protrude from the upper wall portion of the processing container 1 and holds the substrate 9 on the lower surface. The substrate 9 is held by being hooked by a claw (not shown) provided in the substrate holder 4 or electrostatically attracted to the lower surface. In some cases, the gas supply unit 22 is provided on the upper side and the substrate holder 4 is provided on the lower side. In this case, the substrate 9 is placed and held on the upper surface of the substrate holder 4.
The substrate holder 4 also functions as a heating mechanism for heating the substrate 9. That is, a heater 41 for heating the substrate 9 to a predetermined temperature is provided in the substrate holder 4. The heater 41 is of a resistance heating type such as a cartridge heater. The substrate 9 is heated to about room temperature to 300 or 600 ° C. by the heater 41.
[0015]
Next, the configuration of the heating element 3 will be described with reference to FIGS. 1 and 2. FIG. 2 is a schematic plan view illustrating the configuration of the heating element 3 used in the apparatus of FIG. The heating element 3 is a tungsten wire member. A heating element 3 made of a wire-like member is bent in a sawtooth shape and held by a frame 31.
The energy supply mechanism 30 is configured to maintain the heating element 3 at a predetermined high temperature by energizing the heating element 3 to generate Joule heat. Specifically, the energy supply mechanism 30 is an AC power supply that allows a predetermined AC current to flow through the heating element 3. The frame 31 is an insulating material such as ceramic. The energy supply mechanism 30 is configured to maintain the heating element 3 at a high temperature of about 1500 to 1900 ° C.
[0016]
The major feature of the apparatus of the present embodiment is that the heating element 3 is maintained in a vacuum, in a reducing gas atmosphere or in an inert gas atmosphere at a high temperature equal to or higher than the temperature at the time of forming a thin film for a predetermined time. It is a point that is used. More specifically, the heating element 3 in this embodiment is subjected to a high temperature treatment that is maintained at a high temperature of about 2000 to 3000 ° C. for about 5 to 60 minutes in a vacuum of about 1 × 10 ^{−6 to} 1 Pa. is there. After performing such high temperature processing, the heating element 3 is brought into the processing container 1 and attached to a predetermined position.
[0017]
Preliminarily treating the heating element 3 at a high temperature is based on the research of the inventor who analyzed the phenomenon of heavy metal mixing into the thin film described above. As a result of intensive studies as to where the heavy metal mixed in the thin film comes from, the inventor has come to the conclusion that it may come from the heating element 3.
[0018]
More specifically, the tungsten heating element 3 is formed by sintering tungsten powder. At the stage of tungsten powder, it has an extremely high purity of about 99.999% and contains a large amount of the heavy metals described above. It seems that there is no going out. However, when the sintered tungsten material is processed into a wire shape, the tungsten material is rolled while being compressed by a metal compressor. And the compressor which contacts tungsten material is metallic, and iron, nickel, etc. exist in the surface, and it is thought that these heavy metals mix in tungsten material at the time of rolling.
According to the inventor's investigation, when a tungsten material is processed into a wire shape, its purity is about 99.9%, which is two orders of magnitude lower.
[0019]
When film formation is performed using the heating element 3 mixed with heavy metal in this way, the heating element 3 generates heat at a high temperature, and as a result, the mixed heavy metal evaporates and reaches the substrate 9 and is taken into the thin film. . This is considered to be caused by the high concentration of iron, nickel or the like mixed into the thin film.
[0020]
Based on such estimation, the inventor performed a high temperature treatment for maintaining the heating element 3 at a high temperature for a predetermined time as described above, and then brought it into the processing container 1 for use in film formation. The temperature during the high temperature treatment was set to be equal to or higher than the temperature at the time of film formation. That is, the concept is that heavy metal is released in advance by reaching a temperature higher than the temperature reached at the time of film formation. With such a configuration, the release of heavy metals from the heating element 3 during film formation is extremely reduced, and as a result, the mixing of heavy metals into the thin film is also extremely reduced.
[0021]
FIG. 3 is a diagram showing a result of an experiment confirming the effect of the apparatus of the present embodiment.
FIG. 3 shows the result of SIMS analysis of a silicon nitride film formed on a gallium arsenide substrate, as in the experiment shown in FIG. Note that the silicon nitride film was formed using the apparatus of the present embodiment described above. Specifically, the heating element 3 was made of tungsten, and was subjected to a high temperature treatment at a temperature of 2500 ° C. for 7 minutes.
Further, as film formation conditions, the temperature of the heating element 3 is 1800 ° C., the temperature of the substrate 9 is 280 ° C., the pressure in the processing container 1 during film formation is 1 Pa, the source gas is a mixed gas of silane and ammonia, The flow rate ratio was 1: 100, and the overall flow rate was 101 cc / min.
[0022]
As can be seen by comparing FIG. 3 and FIG. 6, it can be seen that Fe and Ni in the silicon nitride film are reduced to the SIMS detection limit and Cr and Mn are reduced to the detection limit or less. These results, by pre-heating above the temperature at the time of forming the heating element 3 as described above, can be removed heavy metal impurities in the heating element 3, indicates that the incorporation into the thin film can be dramatically suppressed ing. Therefore, according to the apparatus of the present embodiment, such a thin film having excellent characteristics with very little mixing of heavy metal impurities can be formed by the heating element CVD method.
[0023]
Next, the problem of the time for high-temperature treatment of the heating element 3 that is important in implementing the apparatus of the present invention will be described. FIG. 4 is a diagram showing the results of an experiment that examined the time for high-temperature treatment of the heating element 3.
In this experiment, a silicon nitride film was formed on the gallium arsenide substrate under the same conditions as in the experiment shown in FIG. However, in this experiment, the heating element 3 that was not subjected to the high temperature treatment was brought into the vacuum vessel 1, and film formation was first performed for 10 minutes (100 nm) under the above conditions (first film formation). Then, after exhausting the inside of the processing container 1 to a pressure of 5 × 10 ⁻⁶ Pa or less, the heating element 3 was subjected to a high temperature treatment at 2500 ° C. for 5 minutes. Then, after the inside of the processing container 1 was evacuated again to a pressure of 5 × 10 ⁻⁶ Pa or less, film formation was performed for 10 minutes under the same conditions as the first film formation (second film formation). Thereafter, the inside of the processing container 1 was again evacuated to 5 × 10 ⁻⁶ Pa or less, and then a high temperature treatment was similarly performed for 5 minutes. As described above, the film forming process was repeated 10 times while alternately performing the film forming process for 10 minutes and the high temperature process for 5 minutes to form a silicon nitride film having a total thickness of about 1 μm. This silicon nitride film was subjected to SIMS analysis, and FIG. 4 schematically shows the concentration distribution of impurities (Cr) in the depth direction in the film from the analysis result. Note that 5 × 10 ¹⁵ atoms / cc is the detection limit of SIMS. Therefore, the density data below this value is represented by an estimated value.
[0024]
As shown in FIG. 4, an impurity concentration of about 4 × 10 ¹⁷ atoms / cc exists in the first film formation, but about 9 × 10 ¹⁵ atoms / cc in the second film formation. It has decreased to. And in the 3rd film-forming, it has decreased to about 6 × 10 ¹⁵ atoms / cc which is close to the detection limit. Further, in the process of repeating the film formation process, it is presumed that the impurity concentration decreases step by step below the detection limit.
[0025]
As can be seen from this result, the impurity concentration decreases by an order of magnitude or more as compared with the case where the high temperature treatment is not performed only by performing the high temperature treatment for about 5 minutes, and the upper limit value of the impurity contamination is 1 ×. It can be seen that the value is less than 10 ¹⁷ atoms / cc.
Therefore, it was confirmed that the high temperature treatment is preferably performed for about 5 minutes or more. Of course, as shown in FIG. 4, the high temperature treatment for 5 minutes or more is more preferable because the impurity concentration is further reduced. In the above experiment, the Cr concentration was analyzed by SIMS, but the same applies to other impurities.
[0026]
Next, the operation of the apparatus according to the present embodiment having the above configuration will be described.
First, the substrate 9 is placed in a load lock chamber (not shown) adjacent to the processing container 1 and the inside of the load lock chamber and the processing container 1 is exhausted to a predetermined pressure. Thereafter, a gate valve (not shown) is opened to remove the substrate 9. It is carried into the processing container 1. The substrate 9 is held by the substrate holder 4. The heater 41 in the substrate holder 4 operates in advance, and the substrate 9 held by the substrate holder 4 is heated to a predetermined temperature by the heat from the heater 41. In parallel, the energy supply mechanism 30 operates, energizes the heating element 3 to generate heat, and maintains a predetermined high temperature.
[0027]
In this state, the gas supply system 2 operates. That is, the valve 24 is opened, and the source gas is supplied into the processing container 1 through the gas supplier 22. The supplied source gas reaches the substrate 9 via the surface of the heating element 3. At this time, the source gas is decomposed and / or activated on the surface of the heating element 3. Then, when the decomposed and / or activated source gas reaches the surface of the substrate 9, a predetermined thin film is deposited on the surface of the substrate 9. When the thin film reaches a predetermined thickness, the supply of the source gas is stopped by closing the valve 24, the inside of the processing container 1 is exhausted again, and then the operation of the energy supply mechanism 6 is stopped. Thereafter, the substrate 9 is taken out from the processing container 1.
[0028]
A specific example of vapor deposition will be described by taking as an example the case of forming a silicon nitride film in the same manner as described above. As source gases, monsilane is 0.1 to 20.0 cc / min, and ammonia is 10.0 to 2000.0 cc / min. Mix and introduce in minutes. When vapor deposition is performed while maintaining the temperature of the heating element 3 at 1600 to 2000 ° C., the temperature of the substrate 9 at 200 to 350 ° C., and the pressure in the processing vessel 1 at 0.1 to 100 Pa, the deposition rate is about 1 to 10 nm / min. A silicon nitride film can be formed at a film speed. Such a silicon nitride film can be effectively used as a passivation film or a protective film.
[0029]
Next, the film forming mechanism using the heating element 3 as described above will be described below. The use of the heating element 3 is to reduce the temperature of the substrate 9 during film formation as described above, but it is not always clear why film formation can be performed even if the temperature of the substrate 9 is lowered. Absent. As one model, the following surface reaction may occur.
[0030]
FIG. 5 is a schematic diagram for explaining one possible model of film formation in the apparatus of this embodiment. Taking the case where the silicon nitride film is formed as an example, when the introduced monosilane gas passes through the surface of the heating element 3 maintained at a predetermined high temperature, the catalytic decomposition of silane similar to the adsorption dissociation reaction of hydrogen molecules. Reaction occurs, and decomposition active species of SiH ₃ and H ^* are generated. Although the detailed mechanism is not clear, when one hydrogen constituting monosilane adsorbs or contacts the tungsten surface, the bond between the hydrogen and silicon weakens and monosilane decomposes, and the adsorption or contact on the tungsten surface is hot. It is considered that the decomposition active species of SiH ₃ and H ^* are generated by being dissolved. A similar catalytic decomposition reaction also occurs in ammonia gas, and decomposition active species of NH ₂ and H ^* are generated. These decomposition active species reach the substrate 9 and contribute to the deposition of the silicon nitride film. In other words, the reaction formula shows
SiH ₄ (g) → SiH ₃ (g) + H ^* (g)
NH ₃ (g) → NH ₂ (g) + H ^* (g)
aSiH ₃ (g) + bNH ₂ (g) → cSiNx (s)
It becomes. The subscript “g” means a gas state, and the subscript “s” means a solid state.
[0031]
Further, the action of the heating element is discussed in detail in the paper of Jan. J. Appl. Pys. Vol. 37 (1998) pp. 3175-3187. In this paper, since the slope of the film formation rate with the temperature of the heating element as a parameter varies depending on the material of the heating element, it is assumed that what occurs on the surface of the heating element is not mere thermal decomposition but catalytic action (same as above). (See Fig. 7). Therefore, this type of CVD method is called a catalytic chemical vapor deposition (catalytic CVD, cat-CVD) method.
[0032]
Furthermore, it can be considered that the film forming method as in the apparatus of the present embodiment is based on the action of thermoelectrons on the surface of the heating element 3. In other words, from the surface of the heating element 4 maintained at a high temperature, the idea is that thermoelectrons act on the raw material gas through the tunnel effect due to the tunnel effect, and as a result, the raw material gas is decomposed or activated. Can do.
[0033]
Any of the above-described ideas can be adopted as the film forming mechanism in the apparatus of the present embodiment. It is also possible to take the idea that these phenomena occur simultaneously. Whichever way of thinking is employed, the surface of the heating element 3 is decomposed, activated, or both decomposed and activated, and this is caused by changes in any of these source gases. The membrane has been. Then, by causing the source gas to reach the substrate 9 through such a heating element 3, it is possible to perform film formation with a relatively low temperature of the substrate 9.
[0034]
In the apparatus of the present embodiment related to the above configuration and operation, as described above, the heating element 3 is preliminarily processed at a temperature higher than the temperature at the time of film formation for a predetermined time. Very little is released. For this reason, the mixing of heavy metals and the like into the thin film is extremely reduced, and a high-quality thin film can be obtained.
[0035]
In the description of the apparatus of the present embodiment, tungsten is taken as the material of the heating element 3, but other high melting point metals such as tantalum and molybdenum may be used.
In addition to the silicon nitride film, the device of the present invention can be used to produce an insulating film such as a silicon oxynitride film and a silicon oxide film, and a semiconductor film such as an amorphous silicon film and a polysilicon film. Can be used.
Moreover, in the said embodiment, although the heat generating body 3 processed at high temperature in the vacuum was used, when performing high temperature processing in reducing gas, such as hydrogen, the oxidation body of the heat generating body 3 was prevented or oxidized High temperature treatment can be performed while reducing Moreover, it is also suitable to perform high temperature processing in inert gas, such as argon and nitrogen, and the oxidation of the heat generating body 3 can be prevented similarly. The flow rate when using the reducing gas or the inert gas may be arbitrary. However, it is preferable that the atmospheric pressure does not exceed atmospheric pressure. This is because if the pressure exceeds atmospheric pressure, impurities may not be released sufficiently.
[0036]
In addition, the heating element 3 is generally provided in the processing container 1 after the high temperature treatment is performed. However, after the heating element 3 is provided in the processing container 1 as described above, the processing container 1 is provided. In some cases, high temperature treatment is performed. In the above description, it has been described that the impurities removed from the heating element 3 are heavy metals, but it is of course not limited thereto. By generating heat above the temperature at the time of film formation, all the impurities that evaporate are removed from the heating element 3, and mixing into the thin film is suppressed.
[0037]
In addition, the energy supply mechanism 30 is energized, that is, supplies electric energy to maintain the heating element 3 at a predetermined high temperature . However, the energy supply mechanism 30 supplies radiation energy to keep the heating element 3 at a predetermined high temperature. It can also be used to maintain the Or what maintains an elevated temperature by irradiating an electron beam or a laser is also employable.
[0038]
【The invention's effect】
As described above, according to the invention of each claim of the present application, since the heating element is preheated to a temperature at which the impurities evaporate, it can be removed even if the impurities are present in the heating element and mixed into the thin film. Is suppressed. For this reason, a thin film having excellent characteristics with very few impurities can be formed by the heating element CVD method. In addition to this effect, there is an effect that a specific problem that impurities are mixed when processing into a wire shape is solved.
[Brief description of the drawings]
FIG. 1 is a front view showing a schematic configuration of a chemical vapor deposition apparatus according to an embodiment of the present invention.
2 is a schematic plan view illustrating the configuration of a heating element 3 used in the apparatus of FIG.
FIG. 3 is a diagram showing a result of an experiment confirming the effect of the apparatus of the present embodiment.
FIG. 4 is a diagram showing a result of an experiment for examining a time for high-temperature treatment of a heating element 3;
FIG. 5 is a schematic diagram for explaining one possible model of film formation in the apparatus of the present embodiment.
FIG. 6 is a diagram showing a result of an experiment confirming a problem of a conventional chemical vapor deposition apparatus, and a diagram showing a result of analyzing a silicon nitride film created by a chemical vapor deposition apparatus for experiment by secondary ion mass spectrometry. is there.
[Explanation of symbols]
1 Processing Container 11 Exhaust System 2 Gas Supply System 3 Heating Element 30 Energy Supply Mechanism 4 Substrate Holder 9 Substrate

Claims (9)

The inside of the processing chamber was evacuated to 1 × 10 -6 ^Pa or more 1Pa or less, and while introducing a reducing gas or inert gas into the processing chamber, tungsten disposed in the processing vessel, of molybdenum or tantalum A first step of energizing the wire-like heating element to generate heat and maintaining it at a first temperature at which iron or nickel contained as impurities in the heating element evaporates for 5 minutes or more ;
After the first step, wherein the heating element for supplying a predetermined raw material gas arranged inside the process chamber, the said heating element is energized to generate heat lower than the first temperature second temperature In this way , the supplied raw material gas is allowed to pass through the surface of the heating element, and the raw material gas is decomposed and / or activated on the surface of the heating element at the time of passing the raw material gas. A second step of creating a predetermined thin film on the substrate ;
Chemical vapor deposition method, which comprises a. 2. The chemical vapor deposition method according to claim 1, wherein the first temperature is 2000 ° C. or more and 3000 ° C. or less, and the second temperature is 1500 ° C. or more and 1900 ° C. or less. 3. The chemical vapor deposition method according to claim 1, wherein the concentration of heavy metal mixed in the predetermined thin film to be created is set to 1 × 10 ¹⁷ atoms / cc or less in secondary ion mass spectrometry. The chemical vapor deposition method according to claim 1, wherein the reducing gas or the inert gas is hydrogen. The chemical vapor deposition method according to claim 1, wherein the reducing gas or the inert gas is argon or nitrogen. A processing container in which predetermined processing is performed on the substrate,
An exhaust system for exhausting the inside of the processing vessel;
A gas supply system for supplying a predetermined source gas into the processing vessel;
A wire-like heating element made of tungsten, molybdenum or tantalum provided in the processing container so that the supplied source gas passes through the surface;
An energy supply mechanism that gives heat to the heating element so that the source gas decomposes and / or activates when the source gas passes, and heats the heating element;
Gas introduction means for introducing a reducing gas or an inert gas into the processing vessel;
A chemical vapor deposition apparatus comprising a substrate holder for holding a substrate at a position in a processing container where a predetermined thin film is created by decomposition and / or activation of a source gas,
State the energy supply mechanism, which before the creation of the thin film, said by the exhaust system was evacuated to 1Pa pressure below than 1 × 10 -6 ^Pa, and was introduced reducing gas or an inert gas by said gas introducing means Then, after the heating element is energized at a first temperature which is a temperature at which iron or nickel contained as impurities in the heating element evaporates for 5 minutes or more to generate heat, the raw material gas is produced during the formation of the thin film. The chemical vapor deposition is characterized in that the heating element is energized to generate heat so that the second temperature lower than the first temperature is a temperature at which decomposition and / or activation occurs. apparatus. The chemical vapor deposition apparatus according to claim 6, wherein the first temperature is 1500 ° C or higher and 1900 ° C or lower, and the second temperature is 2000 ° C or higher and 3000 ° C or lower. The chemical vapor deposition apparatus according to claim 6 or 7, wherein the reducing gas or the inert gas is hydrogen. The chemical vapor deposition apparatus according to claim 6 or 7, wherein the reducing gas or the inert gas is argon or nitrogen.

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