JP2019014976A - Catalyst cvd apparatus, catalyst cvd method and method for self-cleaning catalyst cvd apparatus - Google Patents

Abstract

To provide a catalyst CVD apparatus and method, capable of solving the problem that the improvement of apparatus operation rate and yield is difficult when the catalyst CVD apparatus is applied to a mass-production apparatus since the conventional catalyst CVD apparatus forms silicide by reacting a catalyzer with Si included in raw material gas to cause function deterioration and disconnection and further a catalyzer life is reduced by high temperature even when self cleaning is performed by the catalyzer.SOLUTION: The catalyst CVD method comprises: dividing first raw material gas (Si non-containing gas) contacted and decomposed by a catalyzer from second raw material gas (Si containing gas) not contacted and decomposed by the catalyzer; blocking the catalyzer and the second raw material gas by a partition to prevent both from contacting to each other; reducing the partial pressure of the second raw material gas to the partial pressure of the first raw material gas to suppress contact between both gases; and providing a region in which radicals or decomposition species formed by the catalyzer are contacted and mixed with the second raw material gas.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a catalytic CVD apparatus (cat-CVD apparatus), a catalytic CVD method (cat-CVD method), and a self-cleaning method using plasma of the catalytic CVD apparatus (cat-CVD apparatus).

Catalytic CVD apparatus (cat-CVD apparatus) and catalytic CVD method (cat-CVD method) have no substrate damage (ion damage) caused by charged particles, can form a dense film, and decomposition efficiency of source gas And high-speed film formation is possible, such as the formation of photoelectric conversion films, insulating films, passivation films, barrier films, etc. in solar cells, TFTs for liquid crystal displays, organic EL, and various semiconductor devices. Applications are being made.
In the catalytic CVD method, a source gas is brought into contact with a heated catalyst body and decomposed using a catalytic decomposition reaction generated at that time, and the decomposed species or radicals are transported by a concentration gradient and a temperature gradient. It is a method of transporting and depositing on a substrate using a phenomenon. That is, the catalytic CVD method dissociates and adsorbs source gas molecules on a heated catalyst body, releases the dissociated and adsorbed atoms or various radicals into the gas phase with separation (thermal desorption), and moves by diffusion phenomenon. It is known that atomic radicals or film-forming precursors are deposited on a substrate to form a thin film.

  The principle of the catalytic CVD method, the catalytic CVD apparatus and the development status thereof are described in detail in Non-Patent Document 1 and Non-Patent Document 2, for example.

Non-Patent Document 1 has the following description. That is, as a specific example of film formation, when a silicon (S _i ) -based thin film is formed using S _i H ₄ as a raw material gas and W line as a catalyst body, S _i H ₄ molecules reaching the W surface are If the catalyst body temperature is 1000 ° C. or higher, it is separated into _Si and four H and adsorbed on W (dissociative adsorption). The species adsorbed on the surface of the catalyst body are released into the gas phase while being separated (thermal desorption) because the W catalyst body is hot. Part of the released H radical reacts with undecomposed S _i H ₄ molecules in the gas phase in the process of S _i H ₄ + H → S _i H ₃ + H ₂ . As a result, S _i H ₃ radicals, known as precursors for the formation of such high quality amorphous S _i layer and the microcrystalline S _i film is produced. On the other hand, _Si radicals have a high adhesion coefficient and cannot be expected to migrate on the substrate. Therefore, Si radicals are not preferred from the viewpoint of film densification, but the collision frequency with other molecules and radicals in the gas phase is sufficient. If so, most of them disappear without reaching the substrate by the gas phase reaction. However, the reaction in the gas phase proceeds further, S _i is a chain in the continuous polymer shaped radicals are produced, which is also said to inhibit the formation of dense and high-quality film.

  Non-Patent Document 1 has the following description. That is, one of the problems specific to Cat-CVD is modification of the catalyst body. In particular, in a mass production facility that requires continuous production, extending the life of the catalyst body is a major issue. The modification of the catalyst body means that, when gas molecules to be decomposed are dissociated and adsorbed on the surface of the catalyst body, atoms that are not thermally desorbed react with the constituent elements of the catalyst body to form a compound layer on the surface. This growth of the compound layer proceeds to the inside of the catalyst body while generating a crack in itself, and finally causes disconnection. In order to suppress or delay the growth of the compound layer, one solution is to increase the temperature of the catalyst body to promote thermal desorption of decomposed species.

Non-Patent Document 1 has the following description. That is, tungsten silicide, which is a compound of W and Si, is formed when exposed to a SiH4 atmosphere at any initial catalyst body temperature. From composition analysis, WSi2 is formed at an initial temperature of 1450 ° C., and W5Si3 is formed at 1750 ° C. It can be seen that each is formed. This is probably because the lower the temperature of the catalyst body, the higher the proportion of Si that forms W and the compound layer without thermal desorption, and a silicide layer with a higher Si composition was formed. Since the emissivity of WSi2 is larger than that of W or W5Si3, the temperature of the catalyst body is lowered due to energy loss due to radiation, and thermal desorption is less likely to occur, resulting in the formation of a thick silicide layer and consequently disconnection. On the other hand, the W5Si3 layer has the property that it can be removed by high-temperature heat treatment at about 2100 ° C. even after it is formed. Therefore, in the combination of SiH4 gas and W catalyst body, the initial catalyst body temperature is set so as not to form the WSi2 layer. It needs to be set high to some extent.
Non-Patent Document 1 has the following description. That is, although it is the upper limit of the temperature of the catalyst body during film deposition, there is a report that W is mixed in the deposited a-Si film at a temperature of 2000 ° C. or higher, which is not preferable for device application. Is desirable.

Non-Patent Document 2 has the following description. That is, the decomposition species of S _i H ₄ on the W catalyst body is atomic silicon (S _i ), but the dominant film deposition species are atomic hydrogen (H) and S _i H _{4 in the} gas phase. It was clarified that it was silyl (S _i H ₃ ) produced by the collision.
Non-Patent Document 2 has the following description. That is, consider how decomposed species generated by dissociative adsorption of gas molecules on the catalyst body are transported onto the substrate and a thin film is formed. Depending on the gas used, for example, S _i the catalyst surface in the case of using H ₄ must be at a high temperature of over 1600 ° C.. It is apparent that the high temperature as high as 1600 ° C. is not necessary for the dissociation of S _i H ₄ gas in view of the film formation temperature in the thermal CVD method. In the Cat-CVD method, it is important not to react the catalyst body with the decomposition species of the gas molecules. If the surface of the catalyst body is modified by the reaction, the gas decomposition itself is not reproducible. In other words, a high temperature of 1600 ° C. is necessary to re-release the decomposed species into the gas phase in a short time without staying on the catalyst body surface for a sufficient time for the decomposed species to react with the catalyst body. . If the temperature of the catalyst body is low, the decomposed species can stay on the surface of the catalyst body correspondingly, the decomposed species and the catalyst body react, and the catalyst body is denatured. For example, in the combination of W and S _i H ₄ that is most frequently used for the catalyst body material, silicidation of W occurs.

Further, Non-Patent Document 2 has the following description. That is, the decomposed species released into the gas phase are transported onto the substrate by both thermal diffusion and gas flow, but the Cat-CVD method usually uses a low pressure of about several hundred mPa to several Pa and the gas flow rate is small. Since the flow velocity does not exceed several m / s, it is not easily affected by the gas flow. Needless to say, the Cat-CVD method enables practical film formation at a low pressure and a small flow rate, and also results from high gas decomposition efficiency. Of course, there are cases where the decomposition species are accompanied by a gas phase reaction, but since the transport of decomposition species is governed by thermal diffusion from the catalyst body, the film thickness distribution is generally determined by the geometrical arrangement of the catalyst body. . This is one of the reasons that the design of the Cat-CVD method is facilitated compared to other CVD methods that are easily affected by the gas flow.
Further, Non-Patent Document 2 has the following description. That is, by using the shower head integrated with the catalyst body, it becomes possible to place a wire of any length at an arbitrary position on the shower head without modifying the connection portion of the catalyst body wire and the current introduction terminal. This makes it possible to handle large area deposition. In fact, by using a catalyst body integrated shower head, an a-Si film has been successfully deposited on a substrate of 960 mm × 400 mm with a deposition rate of 5.3 Å / s and a film thickness distribution of ± 7.5%.
Non-Patent Document 2 has the following description. That is, the GaAs substrate temperature when the catalyst body temperature is 1900 ° C. and the substrate holder temperature is 150 ° C. is slow to about 360 ° C. without being saturated even after 200 seconds from the start of heating of the catalyst body when the electrostatic chuck is not used. By using an electrostatic chuck while continuing to raise the temperature, it saturates at only 180 ° C. in about 20 to 40 seconds after starting heating of the catalyst body.

According to the above-described matters described in Non-Patent Document 1 and Non-Patent Document 2, one of the problems unique to the catalytic CVD apparatus is disconnection or functional deterioration of the catalyst body due to modification of the catalyst body (tungsten silicidation).
Modification of the catalyst body (tungsten silicidation) is a chemical phenomenon that occurs when tungsten of the catalyst body is exposed to an SiH4 atmosphere, and is an essential phenomenon of the tungsten catalyst body. In the industrial application of a CVD apparatus, it becomes a serious problem in ensuring the apparatus operation rate and product yield.
However, at present, an effective solution for preventing the modification of the catalyst body (tungsten silicidation) has not been established, and in order to find such a solution, earnest research and development is underway.
In addition, when applying the catalytic CVD apparatus and catalytic CVD method to mass production facilities such as solar cells and various semiconductor devices, when film formation on the substrate is repeated, the film is also applied to members other than the substrate inside the reaction vessel. Is formed. When the attached film becomes thick, it peels off, drops, or scatters and mixes into the film of the substrate, deteriorating the film quality of the product to be manufactured and causing a significant decrease in product yield. For this reason, it is necessary to remove the attached film on the members inside the reaction vessel at an appropriate timing in the film forming process of the various products.
As a technique for removing the film adhering to the members inside the reaction vessel, for example, a self-cleaning method described in Patent Document 5 has been proposed. However, since the self-cleaning technique described in Patent Document 5 needs to heat the tungsten of the catalyst body to 2000 ° C. or more, deterioration due to evaporation of tungsten heated to 2000 ° C. or more occurs, and the life of the catalyst wire is short. And problems such as contamination inside the reaction vessel.
In other words, the self-cleaning technology used in the conventional catalytic CVD apparatus accelerates the deterioration of the catalyst line and shortens its life, so it is necessary to replace the catalyst line frequently, ensuring the apparatus operating rate and product yield. It has become a serious problem.

  For example, Patent Document 1 to Patent Document 4 are representative examples of conventional techniques related to a catalytic CVD apparatus (cat-CVD apparatus) and a catalytic CVD method (cat-CVD method).

Patent Document 1 discloses the following. That is, a processing chamber capable of maintaining a reduced pressure inside, a substrate holder for holding a substrate at a predetermined position in the processing chamber, a gas introduction system for introducing a predetermined source gas into the processing chamber, and a gas introduction A high-temperature medium provided in the processing chamber so that the source gas introduced from the system contacts the surface or passes near the surface, and energy for applying the energy to the high-temperature medium and maintaining the high-temperature medium at a predetermined high temperature A predetermined thin film is formed on the surface of the substrate when the product generated by the source gas contacting the surface of the high temperature medium or passing near the surface reaches the substrate. A chemical vapor deposition apparatus,
The substrate holder holds the substrate vertically, and the high temperature medium is provided along a plane that is a vertical surface and parallel to the substrate held by the substrate holder, and further, the high temperature medium Is a chemical vapor deposition apparatus characterized in that it comprises a plurality of media elements that are separately mounted.

Patent Document 2 describes the following. That is, the raw material gas is supplied to a large number of holes in which the catalyst body is arranged, and radicals or decomposition species generated by catalytic decomposition of the raw material gas with the catalyst body are supplied from the holes to the vacuum chamber. Radical generation method.
Patent Document 2 discloses the following. That is, a radical generator that catalytically decomposes a raw material gas with a catalyst body to generate radicals or decomposition species, and a plurality of holes for supplying the raw material gas supplied from the raw material gas supply means into the decompression chamber; And a catalyst body that is disposed at a predetermined position in the inside and catalytically decomposes the raw material gas.

Patent Document 3 describes the following. That is, a reaction vessel whose pressure can be adjusted by operating an exhaust system, a substrate holder for holding a substrate in the reaction vessel, a gas introduction system for introducing a reaction gas into the reaction vessel, and a substrate holding surface of the substrate holder The reaction gas introduced from the gas introduction system into the reaction vessel is activated or decomposed by the catalyst body heated to a high temperature by energization. In the catalytic CVD apparatus for depositing the deposited species on the substrate held by the substrate holder to form a film, a reaction gas reservoir is provided on the back surface opposite to the substrate holding surface side of the substrate holder, and the substrate A plurality of gas ejection holes are formed so as to penetrate between the back surface of the holder and the substrate holding surface, and a reaction gas is introduced into the reaction gas reservoir from the gas introduction system, and the reaction gas is removed. The reaction gas stored in the reaction gas storage container is ejected to the substrate holding surface side of the substrate holder through the gas ejection hole.
Patent Document 3 describes the following. In other words, the catalyst body is installed perpendicular to the horizontal bottom surface of the reaction vessel, and the two substrate holders are placed on the reaction body with the catalyst body in between and the substrate holding surface side facing each other. It is characterized by being installed substantially perpendicular to the horizontal bottom of the container.

Patent Document 4 describes the following. That is, a reaction vessel containing a substrate holding unit on which a substrate to be deposited is placed and provided with an exhaust unit, a source gas supply unit that supplies a source gas to the reaction vessel, and a catalyst that causes a catalytic reaction to the source gas. A catalytic CVD apparatus comprising: a medium; power supply means for supplying power to the catalyst body to maintain the catalyst body at a predetermined high temperature; and source gas flow control means for guiding the source gas to the catalyst body,
The source gas supply means includes a first source gas supply means for supplying a first source gas that is catalytically decomposed by the catalyst body maintained at a high temperature by the power supplied by the power supply means, and the catalyst body. Comprising a second source gas supply means for supplying a second source gas not subjected to catalytic cracking,
The source gas flow control means induces the first source gas to contact the catalyst body to form a radical generation region for generating radicals or decomposition species of the first source gas by the catalyst body. A precursor of film formation in the gas phase by contacting and mixing the radical or decomposition species of the first source gas generated in the radical generation region and the second source gas supplied from the second source gas supply means Forming a contact mixing region for generating a body, and forming a film-forming precursor formed on the substrate holding means by using a transport phenomenon due to a temperature gradient and a concentration gradient of the film-forming precursor generated in the contact mixing region It is characterized in that it is transported to and deposited on.

JP2000-303182A JP-A-2005-294559 JP 2005-327995 A JP2018-1111887 Patent 4459329

Ohira Keisuke and Matsumura Hideki, Thin Film Formation by Catalytic Chemical Vapor Deposition, Surface Science, Vol. 31, no. 4 (2010), 178-183 Jun Masuda, Ryo Izumi, Hironobu Umemoto, Hideki Matsumura, Catalytic Chemical Vapor Deposition / Recent Progress and Future Prospects Vac. Soc. Jpn. Vol. 46, no. 2 (2003), 92-97

Since the conventional catalytic CVD apparatus uses tungsten as a catalyst body, there is a problem peculiar to tungsten. That is, in the process of forming a silicon-based thin film, there is a problem that the catalyst body is converted into tungsten silicide by reaction with Si contained in the source gas, the function of the catalyst body is deteriorated, and the catalyst body is disconnected. Further, in the self-cleaning process, it is necessary to heat the tungsten of the catalyst body to 2000 ° C. or higher using a fluorine-containing gas. Therefore, deterioration occurs due to evaporation of tungsten due to a high temperature of 2000 ° C. or higher, and the life of the catalyst body. There is a problem of shortening.
The problem of tungsten silicidation of the catalyst body and the shortening of the lifetime of tungsten due to high temperatures significantly lowers the equipment operation rate and product yield when applying the catalyst CVD apparatus to mass production facilities for products such as solar cells and various semiconductor devices. It is a factor of the serious problem That is, in the prior art, it is extremely difficult to ensure the apparatus operation rate and the product yield, and there is a problem that it is difficult to reduce the cost of the product.
The present invention solves the problems of disconnection and functional deterioration of the catalyst body due to the modification of the catalyst body (tungsten silicidation) and the problem of shortening the service life due to high temperature evaporation of tungsten, thereby improving the apparatus operating rate and product yield. It is an object of the present invention to provide a possible catalytic CVD apparatus and method.

The first invention of the present invention for solving the above-mentioned problems is a reaction vessel that contains a substrate holding means on which a film-forming substrate is placed and is equipped with an exhaust means, and supplies a source gas to the reaction vessel A raw material gas supply means; a linear catalyst body that causes a catalytic reaction to the raw material gas; and an electric power supply means that supplies electric power to the catalyst body to maintain a predetermined high temperature. A catalyst for forming a film on a substrate placed on the substrate holding means by catalytically decomposing the source gas introduced into the reaction vessel by the catalyst body heated to a high temperature by the power supplied from the power supply means In the CVD apparatus,
The source gas supply means includes a first source gas supply means for supplying a first source gas that is catalytically decomposed by the catalyst body maintained at a predetermined high temperature by the electric power supplied from the power supply means, and the catalyst. A second source gas supply means for supplying a second source gas that is not catalytically decomposed by the medium;
A region in which the first source gas is brought into contact with the catalyst body and the radical species or decomposition species and the second source gas are brought into contact and mixed with each other is defined by the substrate held by the substrate holding means and the catalyst body. In addition, a partition wall having an opening is disposed between the catalyst body and the second source gas ejection hole for ejecting the second source gas.

  According to a second invention, in the first invention, the partition includes an opening serving as a vent hole, and the catalyst body installed in parallel to the substrate holding surface of the substrate holding means and one surface parallel to the substrate holding surface The catalyst body is disposed at a position sandwiched between second source gas ejection pipes for ejecting the second source gas disposed therein, and the catalyst body has one surface parallel to the partition wall having the opening and the substrate holding surface. The second source gas ejection pipe is disposed at a position sandwiched between first source gas ejection holes for ejecting the first source gas disposed therein, and the partition having the opening and the substrate holding It is characterized by being arranged at a position sandwiched between the substrate holding surfaces of the means.

  According to a third invention, in any one of the first invention and the second invention, the partition wall is made of a metal plate that is electrically grounded and has a plurality of openings. The second source gas ejection pipe is formed of a metal ladder tube that is electrically ungrounded, and includes a second source gas ejection hole for ejecting the second source gas. And connected to an output terminal of a high-frequency power source used for plasma generation.

  In a fourth aspect based on the first aspect, the partition is formed of a metal casing that is electrically grounded, the casing has an opening, and the casing is provided inside the casing. The first source gas ejection hole for ejecting the first source gas and the catalyst body are arranged, and the second source gas ejection pipe for ejecting the second source gas is kept electrically non-grounded, And it is arrange | positioned at the outer periphery of the said housing | casing, and is connected to the output terminal of the high frequency power supply used for plasma production | generation.

  According to a fifth invention, in any one of the second to fourth inventions, the opening of the partition wall has a circular shape, a rectangular shape, a long hole shape, or a slit shape.

According to a sixth invention, in any one of the first to fifth inventions, the first raw material gas is hydrogen (H ₂ ), nitrogen (N ₂ ), ammonia (NH ₃ ), phosphine It is a gas containing at least one selected from (PH ₃ ), diborane (B ₂ H ₆ ), germane (GeH ₄ ), methane (CH ₃ ), and ethane (C ₂ H ₆ ).

According to a seventh invention, in any one of the first to sixth inventions, the second source gas is silane (S _i H ₄ ), disilane (S _i2 H ₆ ), trisilane (S _i3 H _8), characterized in that it is a gas containing at least one selected from monomethyl silane _{(CH 3} S i _{H 3)} and a fluorine-containing gas.

  In an eighth aspect based on any one of the third aspect to the fifth aspect, the second source gas ejection pipe is connected to an output terminal of a high frequency power source for supplying high frequency power for plasma generation. And has a second source gas jet hole for jetting fluorine-containing gas, and the first source gas jet hole communicates with a first source gas supply means for supplying nitrogen or an inert gas. It is characterized by being.

A ninth invention is a catalytic CVD method using the catalytic CVD apparatus according to any one of the first to seventh inventions, wherein a desired thin film is formed on the substrate placed on the substrate holding means When doing
Wherein the reaction vessel partial pressure P ₁ inside during the supply of the first source gas, is set high as compared to the partial pressure P ₂ at the time of supply of the second source gas, and the total pressure P, That is, P = P ₁ + P ₂ with PD product = 0.02 to 0.68 (where P is the unit Pa, D is the distance between the catalyst wire and the partition, and the unit is m) The contact between the catalyst body and the second raw material gas is suppressed by setting the flow range of the gas and radical species around the catalyst body to an intermediate flow in a state between a molecular flow and a viscous flow. The catalytic CVD method characterized by this.

A tenth invention is a plasma cleaning method used for self-cleaning of the catalytic CVD apparatus according to any one of the first to seventh inventions,
When carrying out self-cleaning for removing the film adhering to the reaction container inner member, nitrogen gas or inert gas is ejected from the first source gas ejection hole, and fluorine is ejected from the second source gas ejection pipe. Self-cleaning of the inside of the reaction vessel is performed by jetting a contained gas, supplying electric power from the high-frequency power source to the second source gas jet pipe to generate a fluorine radical by converting the fluorine-containing gas into plasma. It is characterized by that.

In an eleventh aspect based on the tenth aspect, when performing the plasma cleaning for removing the film adhering to the internal member of the reaction vessel, the fluorine-containing gas ejected from the second source gas ejection pipe is: A gas containing at least one selected from NF ₃ , CF ₄ , C ₂ F ₆ , C ₂ F ₈ , SF ₄ , SF ₆ , S ₂ F ₁₀ , XeF ₂ , ClF ₃ and O ₂ To do.

In a twelfth invention according to the tenth invention or the eleventh invention, when performing plasma cleaning for removing the film adhering to the internal member of the reaction vessel,
The partial pressure P ₁ inside the reaction vessel at the time of supplying the first raw material gas is set higher than the partial pressure P ₂ at the time of supplying the second raw material gas, and the total pressure P, that is, P = P ₁ + P _{2 in the range} of PD product = 0.02 to 0.68 (where P is Pa, D is the distance between the catalyst wire and the partition, and the unit is m). The contact between the catalyst body and the fluorine radical is suppressed by making the flow of gas and radical species around the catalyst body an intermediate flow in a state between a molecular flow and a viscous flow.

  By this invention, there exists an effect that the problem of the disconnection of a catalyst body and deterioration of a function by the modification | denaturation (tungsten silicidation, evaporation by high temperature 2000 degreeC or more) which a prior art has can be solved. That is, the present invention makes it possible to extend the life of the catalyst body, and it is difficult to improve the apparatus operation rate and product yield in application to mass production facilities related to products such as solar cells and various semiconductor devices that the conventional catalyst body CVD apparatus has. Therefore, the economic effect is remarkably large.

FIG. 1 is a schematic perspective view for explaining a catalytic CVD apparatus according to the first, second and fourth embodiments of the present invention. FIG. 2 is a schematic perspective view for explaining the first source gas supply means used in the catalytic CVD apparatus according to the first, second and fourth embodiments of the present invention. FIG. 3 is a schematic perspective view for explaining a catalyst body used in the catalytic CVD apparatus according to the first and second embodiments of the present invention and means for supplying power to the catalyst body. FIG. 4 is a schematic perspective view for explaining the second source gas supply means or plasma generation power supply means used in the catalytic CVD apparatus according to the first, second and fourth embodiments of the present invention. FIG. FIG. 5 is a schematic cross-sectional view for explaining the configuration of the catalytic CVD apparatus according to the first embodiment of the present invention. FIG. 6 is a view for explaining the movement of atomic H and the movement of SiH 4 gas, the contact mixing region where both are in contact with each other, and the movement of the precursor for film formation in the catalytic CVD apparatus according to the first embodiment of the present invention. FIG. FIG. 7 is a schematic explanatory view for explaining the reaction between atomic H and SiH 4 in the contact mixing region of the catalytic CVD apparatus according to the first embodiment of the present invention. FIG. 8 is a schematic diagram for explaining the movement of the contact mixing region of atomic H, NH ₂ radicals and S _i H ₄ gas and the precursor of film formation in the catalytic CVD apparatus according to the second embodiment of the present invention. It is explanatory drawing. FIG. 9 is a schematic cross-sectional view for explaining the configuration of a catalytic CVD apparatus according to the third embodiment of the present invention. FIG. 10 is a schematic perspective view for explaining a ladder-type second source gas ejection pipe used in the catalytic CVD apparatus according to the third embodiment of the present invention. FIG. 11 is a schematic cross-sectional view for explaining the configuration of a catalytic CVD apparatus and a self-cleaning method of the catalytic CVD apparatus according to the fourth embodiment of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each figure, the same code | symbol is attached | subjected to the same member and the overlapping description is abbreviate | omitted.
In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual one for convenience of explanation. In addition, the scale may be different between the drawings.

(First embodiment)
A catalytic CVD apparatus and a catalytic CVD method according to the first embodiment of the present invention will be described. First, the configuration of the catalytic CVD apparatus will be described.
FIG. 1 is a schematic perspective view for explaining a catalytic CVD apparatus according to the first, second and fourth embodiments of the present invention.
FIG. 2 is a schematic perspective view for explaining the first source gas supply means used in the catalytic CVD apparatus according to the first, second and fourth embodiments of the present invention.
FIG. 3 is a schematic perspective view for explaining a catalyst body used in the catalytic CVD apparatus according to the first and second embodiments of the present invention and means for supplying power to the catalyst body.
FIG. 4 is a schematic perspective view for explaining the second source gas supply means or plasma generation power supply means used in the catalytic CVD apparatus according to the first, second and fourth embodiments of the present invention. FIG.
FIG. 5 is a schematic cross-sectional view for explaining the configuration of the catalytic CVD apparatus according to the first embodiment of the present invention.
FIG. 6 is a view for explaining the movement of atomic H and the movement of SiH 4 gas, the contact mixing region where both are in contact with each other, and the movement of the precursor for film formation in the catalytic CVD apparatus according to the first embodiment of the present invention. FIG.
FIG. 7 is a schematic explanatory view for explaining the reaction between atomic H and SiH 4 in the contact mixing region of the catalytic CVD apparatus according to the first embodiment of the present invention.

In the following description, the reaction vessel 1 means a film forming chamber. In general, the film forming chamber includes a loading chamber and an unloading chamber so that the inside of the film forming chamber is not exposed to the atmosphere. For convenience of explanation, only the reaction chamber 1 that is a film forming chamber is illustrated, The load room and unload room are omitted.
1 to 6, reference numeral 1 denotes a reaction vessel. The reaction vessel 1 has airtightness, and the degree of vacuum reached 2.66 × 10 ⁻⁴ Pa (2 × 10 ⁻⁶⁾ by exhausting through the first and second exhaust holes 2 a and 2 b with a vacuum pump (not shown). Torr). Further, the inner wall of the reaction vessel 1 does not have impurities attached and satisfies the specifications applicable to catalytic CVD.
Reference numerals 2a and 2b denote first and second exhaust holes. The first and second exhaust holes 2a, 2b are exhausted so as to maintain the pressure inside the reaction vessel 1 at a predetermined value in cooperation with a vacuum pump (not shown) and a pressure gauge (not shown). Here, if the flow rate of the source gas to be described later is about 5 sccm to 500 sccm, the pressure can be set to an arbitrary pressure in the range of about 0.1 Pa to 100 Pa (0.75 mTorr to 750 mTorr) and kept at a constant pressure.

Reference numeral 3 denotes a substrate for film formation. The substrate 3 is a substrate made of glass, plastic, silicon, or the like. The substrate material can be arbitrarily selected. Here, for example, as the substrate 3, glass of size: 15 cm square x thickness of 0.63 mm is used.
Reference numeral 3a denotes a substrate holding means for placing the substrate 3 thereon. The substrate holding means 3a includes a cooling means and a heating means so as to adjust the temperature of the substrate 3, and includes a substrate temperature control device. When the temperature of the below-described catalyst body 10 is set to 1000 ° C. to 1900 ° C., the substrate temperature control device can set and maintain the temperature of the substrate 3 at an arbitrary value in the range of 30 ° C. to 350 ° C.

The substrate 3 is placed on the substrate holding means 3a by a substrate carry-in device (not shown) from a load chamber (not shown), and is moved to an unload chamber (not shown) after film formation. And it is carried out from the unload chamber which is not illustrated.
The distance between the substrate holding means 3a and the later-described catalyst body 10 is set in a range of 2 cm to 20 cm, for example, 10 cm.
The catalytic CVD apparatus transports the radicals or separated species of the source gas generated by the catalyst body 10 described later to the surface of the substrate 3 using the transport phenomenon due to the temperature gradient and the concentration gradient, so that the film thickness is uniform. From the standpoint of conversion, the distance between the catalyst body 10 and the substrate 3 is preferably long.

Reference numeral 20 denotes a housing. A plurality of casings 20 are installed in order to prevent contact between a later-described catalyst body and a later-described second source gas. Here, for example, three are installed, and each is referred to as a first casing 20a, a second casing 20b, and a third casing 20c. Note that the first housing 20a, the second housing 20b, and the third housing 20c are referred to as the housing 20 when it is not necessary to distinguish them. The dimensions of the housing 20 can be arbitrarily selected, but here, for example, a rectangular box shape of 150 mm long × 30 mm wide × 15 mm deep is used. However, as shown in FIGS. 1 and 5, one surface is provided with a vent 20 d. Here, the vent is also referred to as opening 20d.
The housing 20 is made of a metal material, is electrically connected to the reaction vessel 1 and is in a grounded state. Inside the housing 20, a first source gas ejection hole 19 a for ejecting a first source gas described later and a catalyst body 10 described later are installed. Further, the housing 20 is provided with an opening 20d which is a vent hole to be described later.
The casing 20 is a partition wall located between the catalyst body 10 and the second source gas ejection pipe 26b, and the second source gas ejected from the second source gas ejection pipe 26b is molecularly flowed. Even when it behaves, it is difficult for the gas molecules to contact the catalyst body. As will be described later, by setting a high partial pressure P ₁ of the first raw material gas ejected in the casing 20 than the partial pressure P ₂ of the second source gas, the second source gas catalyst Access to the medium 10 is difficult.
Reference numeral 20d denotes a vent hole. The vent 20 d is an opening provided on a surface parallel to the substrate 3 placed on the substrate holding means of the housing 20. The vent 20d allows a first source gas ejected from a first source gas ejection hole 19a, which will be described later, to contact a catalyst body 10, which will be described later, and pass through radical species or decomposed species that are generated by a catalytic reaction. The shape of the vent 20d can be arbitrarily selected from a circular shape, a rectangular shape, a long hole shape, and a slit shape. The opening rate of the vent 20d is preferably 30% or more in order to increase the air permeability of radical species or decomposed species. Here, the aperture ratio is 70%.

The gas flow inside the housing 20 is a molecular flow region (referred to as molecular flow when the mean free path of molecules is larger than the typical length inside the housing: there is no collision between molecules, and molecules collide with walls. Intermediate flow, which is the region between the viscous flow region (when the mean free path of molecules is sufficiently smaller than the typical length inside the housing is called viscous flow: molecules move while colliding with each other) Set the pressure condition to be in the area. When the pressure is represented by P (unit Pa) and the representative dimension of the housing is represented by D (unit m), if the PD product is 0.02 Pa · m or less, it is a molecular flow and the PD product is 0.68 Pa. It is generally known that if it is m or more, it is a viscous flow, and if it is in the range of 0.02 Pa · m to 0.68 Pa · m, it is an intermediate flow.
For example, when the pressure P inside the housing 20 is set to 30 Pa and the typical dimension D of the housing is 15 mm, the PD product = 30 Pax15 × 10 ⁻³ m = 0.45 Pa · m, and the gas flow is an intermediate flow It is. In this case, some of the gas molecules move while colliding with the wall of the housing 20, and some of the gas molecules move while colliding with each other.

Reference numeral 23 (23a, 23b, 23c) denotes a first source gas supply source. The first source gas supply source 23 (23a, 23b, 23c) is hydrogen (H ₂ ), nitrogen (N ₂ ), ammonia (NH ₃ ), phosphine (PH ₃ ), diborane (B ₂ H ₆ ), germane A source gas containing at least one selected from (GeH ₄ ), methane (CH ₃ ), and ethane (C ₂ H ₆ ) is provided. In addition, when selecting several raw material gas, several raw material gas according to it is prepared. In addition, a plurality of source gas flow meters 24 (24a, 24b) corresponding thereto are prepared. Here, for example, hydrogen gas is selected.
Reference numeral 23a denotes a hydrogen gas supply source. The hydrogen gas supply source 23a supplies the source gas H ₂ gas to the first source gas supply pipe 25a described later via the hydrogen gas flow meter 24a.
Reference numeral 24a is a hydrogen gas flow meter. The hydrogen gas flow meter 24a sets the flow rate of the hydrogen gas supplied from the hydrogen gas supply source 23a to an arbitrary flow rate selected in advance, and supplies it to the first source gas supply pipe 25a. Here, the flow rate of the hydrogen gas flow meter 24a can be set to an arbitrary flow rate in the range of 5 sccm to 500 sccm.

Reference numeral 25a denotes a first source gas supply pipe. The first source gas supply pipe 25a supplies the first source gas supplied from the first source gas supply source via the first source gas flow meters 24a and 24b to a first source gas supply box described later. 26.
Reference numeral 27 denotes a joint of a raw material gas supply pipe for a vacuum apparatus. The joint 27 of the raw material gas supply pipe for a vacuum apparatus transports the first raw material gas from the atmosphere side to the inside of the reaction vessel 1 so that there is no vacuum leak.
Reference numeral 26a denotes a first source gas supply box. The first source gas supply box 26a supplies the first source gas supplied from the first source gas supply pipe 25a to the first source gas ejection hole 19a described later.

Reference numeral 19a denotes a first source gas ejection hole. The first source gas ejection hole 19 ejects the first source gas supplied from the first source gas supply source 23 (23 a, 23 b) into the housing 20. The ejected first source gas comes into contact with a catalyst body 10 which will be described later and is catalytically decomposed.
The diameters of the first source gas ejection holes 19a are about 0.2 mm to 1.0 mm, and are arranged at intervals of about 2 mm to 10 mm. Here, the hole diameter is 0.6 mm, and the hole interval is 5 mm. The jet flow of the first source gas is indicated by reference numeral 35a in FIGS.
In general, if the pressure inside the first source gas injection box 26 is about 0.3 MPa (3 kgf / cm ² ) or more, source gas ejection with the hole diameter of about 0.2 mm to 1.0 mm is performed. The flow rate of the source gas injected from the hole 19a is substantially constant, and the influence of the location of the source gas ejection hole 19a is small. That is, there is no variation in the flow rate ejected from each of the numerous source gas ejection holes 19a. That is, the amount of the first raw material gas ejected to the area close to the catalyst body 10 is ejected substantially uniformly.
Further, it is generally known that the velocity of the jet of the source gas ejected from the first source gas ejection hole 19a becomes almost zero when it is separated from the hole by a distance of about 5 to 10 times its diameter. ing. That is, at a point away from the source gas ejection hole 19a by a distance of about 5 to 10 times the diameter of the hole, the influence of the flow of the jet flow is reduced, and the source gas is caused by the concentration gradient and temperature gradient of the source gas. Move by transport phenomenon.

Reference numeral 17 (17a, 17b) denotes a second source gas supply source. The second source gas supply source 17 (17a, 17b) includes silane (S _i H ₄ ), disilane (S _i2 H ₆ ), trisilane (S _i3 H ₈ ), and monomethylsilane (CH ₃ S _i H ₃ ). Or a gas containing at least one selected from NF ₃ , CF ₄ , C ₂ F ₆ , C ₂ F ₈ , SF ₄ , SF ₆ , S ₂ F ₁₀ , XeF ₂ , ClF ₃ and O ₂ A gas containing at least one kind is provided. In addition, when selecting several raw material gas, several raw material gas according to it is prepared. In addition, a plurality of source gas flow meters 17 (17a, 17b) corresponding thereto are prepared. Here, for example, silane (S _i H ₄ ) gas is selected.
Reference numeral 17a is a silane gas supply source. The silane gas supply source 17a supplies a silane gas, which is a raw material gas, to a second raw material gas supply pipe 25b described later via a silane gas flow meter 18a.
Reference numeral 18a is a silane gas flow meter. The silane gas flow meter 18a sets the flow rate of the silane gas supplied from the silane gas supply source 17a to an arbitrary flow rate selected in advance, and supplies it to the second source gas supply pipe 25b. Here, the flow rate of the silane gas flow meter 18a can be set to an arbitrary flow rate in the range of 1 sccm to 100 sccm.

Reference numeral 25b denotes a second source gas supply pipe. The second source gas supply pipe 25b communicates with the silane gas flow meter 18a and the NF ₃ gas flow meter 18b. The second source gas supply pipe 25b communicates with a later-described second source gas ejection pipe 26b through an after-mentioned vacuum device insulating source gas connecting pipe 28.
Reference numeral 28 denotes an insulating material gas connection pipe for a vacuum apparatus. The vacuum source insulating material gas connection pipe 28 connects the second source gas supply pipe 25b and a second source gas ejection pipe 26b described later.
Reference numeral 26b denotes a second source gas ejection pipe. The second source gas ejection pipe 26b supplies the second source gas supplied from the second source gas supply pipe 25b to a second source gas ejection hole 19b described later.

Reference numeral 19b denotes a second source gas ejection hole. The second source gas ejection hole 19b is installed in the second source gas ejection pipe 26b and ejects the second source gas.
The diameters of the second source gas ejection holes 19b are about 0.2 mm to 1.0 mm, and are arranged at intervals of about 2 mm to 10 mm. Here, the hole diameter is 0.6 mm, and the hole interval is 5 mm. The jet flow of the second source gas is indicated by reference numeral 35b in FIGS.
In general, when the pressure inside the second source gas injection pipe 26b is about 0.3 MPa (3 kgf / cm ² ) or more, the source gas is ejected with the hole diameter of about 0.2 mm to 1.0 mm. The flow rate of the source gas injected from the hole 19b is substantially constant, and the influence of the location of the source gas ejection hole 19b is small. That is, there is no variation in the flow rate ejected from the individual holes of the large number of source gas ejection holes 19b.

  Reference numeral 10 denotes a linear catalyst body. The linear catalyst body 10 uses a tungsten wire (W). The cross-sectional shape of the catalyst body 10 is selected from a circle, a rectangle, or an ellipse. When the wiring is circular, it is convenient to handle the wiring. However, when the surface area of the catalyst body is large, a rectangular or elliptical shape is better. For the catalyst body 10, a W wire having a wire diameter of 0.02 to 1.0 mm is selected. Here, a W wire having a circular wire diameter of 0.6 mm is selected. The length of the catalyst body 10 in the direction parallel to the surface of the substrate 3 is approximately 14 cm.

Reference numerals 5a and 5b denote current introduction terminals for vacuum of electric power supplied to the catalyst body. The current introduction terminals 5a and 5b are provided with a current introduction terminal cooling device provided with a cooling refrigerant (not shown). Note that the vacuum current introduction terminals 5a and 5b are electrically connected to the atmosphere-side power supply lines 7a and 7b and the catalyst support rod 8 inside the reaction vessel 1 with no vacuum leakage.
Reference numeral 8 denotes a catalyst support rod. The catalyst body support rod 8 conducts the current introduction terminal 5 and the catalyst body. However, the catalyst body support rod 8 is an insulator (not shown) and is electrically insulated from the casing 2 and is kept in a non-grounded state.
Reference numeral 6 denotes a power source for heating the catalyst. The catalyst heating power source 6 supplies power to the catalyst body 10 via the power supply lines 7 a and 7 b, the vacuum current introduction terminals 5 a and 5 b, and the catalyst body support rod 8. The relationship between the output of the catalyst heating power source 6, the temperature of the catalyst body 10, the flow rate and flow rate ratio of the raw material gas, and the pressure in the reaction vessel 1 is grasped in advance, and the required temperature is determined based on the data. Set to.

Then, using the catalytic CVD apparatus shown in FIGS. 1 to 5, takes a-S _i film is a passivation film heterojunction solar cells, the following description will discuss the film forming method.
Here, take a-S _i film is a passivation film heterojunction solar cell as an example, the hydrogen (H ₂₎ as the first material gas, silane as the second source gas (S i _{H 4)} The film forming method will be described, but it should be understood that the catalytic CVD apparatus and the catalytic CVD method according to the first embodiment of the present invention are not limited to the formation of the a- _Si film.

For example, when forming a p-type a-Si film of a solar cell, a mixed gas of hydrogen (H ₂ ) and diborane (B ₂ H ₆ ) is used as the first source gas, and silane (S _i H ₄ ) is preferred.
For example, when forming an n-type a-Si film of a solar cell, a mixed gas of hydrogen and phosphine (PH ₃ ) is used as the first source gas, and silane (S _i H ₄ ) is used as the second source gas. It is good to choose.
Further, for example, when an amorphous silicon carbide (a-SiC) film is formed, hydrogen (H ₂ ), methane (CH ₄ ), ethane (C ₂ H ₆ ), ethylene (as the first source gas) C ₂ H ₆ ) and silane (S _i H ₄ ) may be selected as the second source gas.
For example, when an amorphous silicon germanium (a-SiGe) film is formed, a mixed gas of hydrogen (H ₂ ) and germane (GeH ₄ ) is used as the first source gas, and silane is used as the second source gas. It is better to select (S _i H ₄ ).
For example, in the case of forming a silicon oxide (S _i O ₂ ) film, a mixed gas of oxygen (O ₂ ) and nitrous oxide (N ₂ O) is used as the second source gas as the first source gas. It is preferable to select silane (S _i H ₄ ).

For example, in the case of forming an S _i CN film as a sealing film of an organic EL device, a mixed gas of hydrogen (H ₂ ) and ammonia (NH ₃ ) is used as the second raw material as the first raw material gas. is good pick monomethyl silane _{(CH 3} S i _{H 3)} as a gas.

Here, the substrate 3 is, for example, glass having a size: 150 mm × 150 mm × thickness 0.63 mm.
A substrate moving door between the load chamber and the reaction vessel 1 is opened for a substrate 3 prepared in advance in a load chamber (not shown), and the substrate 3 is placed on the substrate holding means 3a by a substrate moving device (not shown). Then, the substrate moving door (not shown) is closed.

Next, a vacuum pump (not shown) is operated, and the pressure inside the reaction vessel 1 is once lowered to a degree of vacuum, for example, about 2.67 × 10 ⁻⁴ Pa (2 × 10 ⁻⁶ Torr).
Next, the flow rate of the hydrogen gas is set to about 10 sccm to 200 sccm, for example, 50 sccm by the flow meter 24a of the hydrogen gas that is the first source gas.
Then, using a pressure gauge (not shown) and a vacuum pump (not shown), the internal pressure of the reaction vessel 1 is set to about 1.33 Pa to 30 Pa (0.01 Torr to 0.225 Torr), for example,
Set to 20 Pa (150 mTorr) and maintain. In this state, the displacement of a vacuum pump (not shown) is constant.
Next, after confirming that the pressure of the hydrogen gas that is the first source gas is maintained at 20 Pa, while gradually opening an outlet valve (not shown) of the flow meter 17a of the silane gas that is the second source gas, When the value of a pressure gauge (not shown) inside the reaction vessel 1 reaches 30 Pa while slightly increasing the flow rate of the second source gas, the flow rate of the second source gas is kept constant at that value. That is, the partial pressure of the first source gas (hydrogen) is set to 20 Pa (150 mTorr), the partial pressure of the second source gas (silane) is set to 10 Pa, and the total pressure P (20 Pa + 10 Pa) is set to 30 Pa (225 mTorr). maintain.
Note that the above-described adjustment operation of the first source gas and the second source gas may be automatically performed by a computer control method using a solenoid valve, a digital flow rate control device, or the like (not shown).
Next, electric power is supplied from the catalyst heating power source 6 to the catalyst body 10 through the power supply lines 7a and 7b and the vacuum current introduction terminals 5a and 5b, respectively, to generate heat.
The temperature of the catalyst body 10 is in the range of 1000 ° C. to 1900 ° C., for example, 1700 ° C. In addition, the data grasped in advance, that is, the relationship between the output of the catalyst heating power source 6, the temperature of the catalyst body 10, and the pressure of the reaction vessel 1 is utilized.
The temperature of the substrate 3 is set in the range of 80 ° C. to 350 ° C., for example, 150 ° C. and maintained.

The H ₂ gas ejected from the first source gas ejection hole 19 a diffuses while contacting the catalyst body 10. The H ₂ gas that has contacted the high temperature catalyst body 10 set at 1700 ° C. causes a catalytic reaction. That is, the H ₂ molecule that has contacted the surface of the catalyst body 10 is separated into two atomic H and adsorbed on the catalyst body 10 (dissociative adsorption). The atomic H adsorbed on the surface of the catalyst body 10 is released into the gas phase while being separated (thermal desorption) because the catalyst body 10 is at a high temperature. Here, here, the released atomic H is called a radical or a decomposed species.
The released atomic H moves from the catalyst body 10 toward the substrate 3 due to a transport phenomenon caused by a temperature gradient and a concentration gradient. A situation in which the H radical diffuses and moves is schematically indicated by reference numeral 37a in FIG.

On the other hand, from the silane gas supply source 17a which is the second source gas, the silane gas flow meter 18a, the second source gas supply pipe 25b, the vacuum source insulator source gas connection pipe 28, and the second source gas ejection hole pipe 26b. The silane gas supplied via is ejected from the second source gas ejection hole 19b. The jetted silane gas diffuses and moves between the casings 20 due to a transport phenomenon caused by a temperature gradient and a concentration gradient.
The movement state of the silane gas ejected from the second source gas ejection hole 19b is schematically shown as reference numeral 35b in FIGS.

The H radical generated by the high-temperature catalyst body 10 set at 1700 ° C. and the silane gas ejected from the second raw material gas ejection hole 19b diffuse and move inside the reaction vessel 1, but as shown in FIG. Contact mixing occurs with each other. This contact mixing region is indicated by reference numeral 33a in FIG.
In the contact mixing region 33a, a chemical reaction represented by the following formula occurs.
S _i H ₄ + H → H ₂ + S _i H ₃
Note that the reaction between S _i H ₄ and H occurring in the contact mixing region 33a is schematically shown in FIG.
In the above reaction process, the S _i H ₃ radical has a feature that it has a long lifetime and moves by a transport phenomenon due to a temperature gradient and a concentration gradient, and is a good precursor for the formation of a silicon-based thin film. Move, reach and deposit. The S _i H ₃ radical, which is indicated by the reference numeral 38a in FIG. 6, is a precursor that forms a high-quality film. Therefore, the a-Si film formed on the substrate 3 is a high-quality film.
In addition, since the film-forming speed of the a-Si film depends on the concentration of the source gas S _i H ₄ and the atomic H, when the film is formed at a particularly high speed, the film-forming speed and the pressure are set in advance. It is preferable to perform optimization by grasping the relationship between the conditions, the supply amount of the raw material gas, and the flow rate ratio.

Next, when a predetermined film forming time elapses, for example, for 1 minute in the above film forming, the valve of the first source gas supply source 23a (not shown) and the valve of the second source gas supply source 17a (not shown) are closed. , Stop supplying the source gas. Then, the output of the catalyst heating power source 6 is reduced to zero.
Here, the film forming time is an elapsed time from the time when the temperature of the catalyst body 10 is operated at 1700 ° C. In the case where the film forming time is accurately performed, it is preferable to use a shutter mechanism that can be opened and closed in the vicinity of the substrate 3.
Thereafter, a substrate moving door (not shown) between the reaction chamber 1 and an unloading chamber (not shown) is opened, and the substrate 3 is moved from the substrate holding means 3a to the unloading chamber (not shown) by a substrate moving device (not shown). Then, a substrate moving door (not shown) is closed.

Since the substrate 3 to be deposited has been removed from the substrate holding means 3a of the reaction chamber 1, the substrate 3 is newly moved from a load chamber (not shown). As described above, the substrate 3 prepared in advance in a load chamber (not shown) is opened, the substrate moving door between the load chamber and the reaction chamber 1 is opened, and the substrate 3 is mounted on the substrate holding means 3a by the substrate moving device (not shown). Put. Then, a substrate moving door (not shown) is closed.
Then, the above-described film forming process is repeated for a predetermined number of times, for example, 1000 substrates.

According to the configuration of the catalytic CVD apparatus according to the first embodiment of the present invention, the housing 20 is installed as a partition between the second source gas ejection hole 19b and the catalyst body 10, and the second source gas ejection The state in which the temperature of the catalyst body 10 (1700 ° C.) is significantly higher than the temperature in the vicinity of the hole 19b is maintained, and the partial pressure (for example, 20 Pa) at the time of supplying the hydrogen gas of the first raw material gas is the second value. It is kept at a higher state than the partial pressure (for example, 10 Pa) when the source gas is supplied with silane gas.
As a result, the contact between the catalyst body 10 and the _Si H ₄ gas molecules that cause the tungsten silicide of the catalyst body 10 is prevented.
That is, when (i) S _i H ₄ gas molecules do not collide with other molecules and move while colliding with the surrounding walls (molecular flow), they collide with the wall of the casing 20 and the catalyst body 10 (B) When S _i H ₄ gas molecules move by diffusion based on the temperature gradient, the diffusion force (thermophoretic force) based on the temperature gradient works from the higher temperature side to the lower temperature side. _{The i} H ₄ gas molecules move away from the catalyst body 10. (c) When the S _i H ₄ gas molecules move by diffusion based on the concentration gradient, the partial pressure around the catalyst body 10 is the second raw material gas ejection Since it is larger than the partial pressure around the hole 19b, the movement due to the concentration gradient moves away from the catalyst body 10. As a result, contact between Si atoms and tungsten does not occur, so that tungsten silicidation does not occur in the catalyst body 10. That is, deterioration and disconnection of the catalyst body 10 due to tungsten silicidation do not occur.

  According to the configuration of the catalytic CVD apparatus according to the first embodiment of the present invention, it is possible to easily solve the problem of deterioration of the catalytic body function and disconnection due to tungsten silicidation of the catalytic body of the conventional catalytic CVD and catalytic CVD method. . That is, when the catalytic CVD apparatus is applied to mass production facilities for products such as solar cells and various semiconductor devices, it can contribute to a significant improvement in apparatus operation rate and product yield.

(Second Embodiment)
Next, a catalytic CVD apparatus and a catalytic CVD method according to the second embodiment of the present invention will be described with reference to FIGS. 1 to 4 and FIG. The catalytic CVD apparatus according to the second embodiment of the present invention also uses the members used in the catalytic CVD apparatus according to the first embodiment of the present invention.
In the drawings shown below, the scale of each member may be different from the actual one for convenience of explanation. In addition, the scale may be different between the drawings.

FIG. 8 is a schematic diagram for explaining the movement of the contact mixing region of atomic H, NH ₂ radicals and S _i H ₄ gas and the precursor of film formation in the catalytic CVD apparatus according to the second embodiment of the present invention. It is explanatory drawing.

1-4, the code | symbol 23b is an ammonia supply source. The ammonia supply source 23b supplies the raw material gas ammonia (NH ₃ ) to the raw material gas supply pipe 25a via the ammonia flow meter 24b.
Reference numeral 24b is an ammonia flow meter. The ammonia flow meter 24b sets the flow rate of ammonia (NH ₃ ) gas supplied from the ammonia supply source 23b to an arbitrary flow rate selected in advance, and supplies it to the first source gas supply pipe 25a. Here, the flow rate of the ammonia (NH ₃ ) flow meter 24 b can be set to an arbitrary flow rate in the range of 5 sccm to 500 sccm.

Then, using the catalytic CVD apparatus shown in FIGS. 1 to 4, it takes the S _i N _x film is the antireflection film heterojunction solar cells, the following description will discuss the film forming method.
Here, the S _i N _x film, which is an antireflection film of a heterojunction solar cell, will be described as an example, and the film forming method will be described. The catalytic CVD apparatus and catalytic CVD method according to the second embodiment of the present invention Is not limited to the formation of S _i N _x films.

For example, when forming a _S i CN film as the sealing film of the organic EL device, as a first raw material gas, a mixed gas of hydrogen _{(H 2)} and ammonia (NH _3), as a second source gas , it is to choose a monomethyl silane _{(CH 3 S i H 3)} .

Here, the substrate 3 is, for example, glass having a size: 150 mm × 150 mm × thickness 0.63 mm.
A substrate moving door between the load chamber and the reaction vessel 1 is opened for a substrate 3 prepared in advance in a load chamber (not shown), and the substrate 3 is placed on the substrate holding means 3a by a substrate moving device (not shown). Then, a substrate moving door (not shown) is closed.

Next, a vacuum pump (not shown) is operated to lower the pressure inside the reaction vessel 1 to a vacuum level, for example, about 2.67 × 10 ⁻⁴ Pa (2 × 10 ⁻⁶ Torr).
Next, the flow rate of hydrogen gas is set to about 5 sccm to 500 sccm, for example, 80 sccm by the hydrogen gas flow meter 24a. Ammonia flow rate of (NH ₃₎ ammonia (NH ₃₎ flow meter 24c of the gas gas, about 5Sccm～500sccm, for example, set to 20 sccm.
Then, using a pressure gauge (not shown) and a vacuum pump (not shown), the internal pressure of the reaction vessel 1 is set to about 1.33 Pa to 30 Pa (0.01 Torr to 0.225 Torr), for example,
Set to 20 Pa (150 mTorr). In this state, the displacement of a vacuum pump (not shown) is constant.
Next, after confirming that the pressures of the hydrogen gas and ammonia (NH ₃ ) gas as the first source gas are maintained at 20 Pa, the outlet valve (not shown) of the flow meter 17a of the silane gas as the second source gas When the value of a pressure gauge (not shown) inside the reaction vessel 1 reaches 30 Pa, the flow rate of the second source gas is kept constant at that value. . That is, the partial pressure of the first source gas (mixed gas of hydrogen and ammonia) is 20 Pa (150 mTorr), the partial pressure of the second source gas (silane) is 10 Pa, and the total pressure P (20 Pa + 10 Pa) is 30 Pa (225 mTorr). ) And maintain.
Note that the above-described adjustment operation of the first source gas and the second source gas may be automatically performed by a computer control method using a solenoid valve, a digital flow rate control device, or the like (not shown).
Next, electric power is supplied from the catalyst heating power source 6 to the catalyst body 10 through the power supply lines 7a and 7b and the vacuum current introduction terminals 5a and 5b, respectively, to generate heat.
The temperature of the catalyst body 10 is in the range of 1000 ° C. to 1900 ° C., for example, 1800 ° C. In addition, the data grasped in advance, that is, the relationship between the output of the catalyst heating power source 6, the temperature of the catalyst body 10, and the pressure of the reaction vessel 1 is utilized.
The temperature of the substrate 3 is set in the range of 80 ° C. to 350 ° C., for example, 150 ° C. and maintained.

The mixed gas of H ₂ gas and ammonia gas ejected from the first source gas ejection hole 19 a diffuses while contacting the catalyst body 10. FIG. 8 shows a mixed gas of H ₂ gas and ammonia gas by reference numeral 35a. H ₂ and NH ₃ in contact with the high temperature catalyst body 10 set at 1800 ° C. cause a catalytic reaction. That is, the H ₂ molecule and the NH ₃ molecule that have contacted the surface of the catalyst body 10 are catalytically decomposed into atomic H and NH ₂ radicals and released into the gas phase. The released atomic H and NH ₂ radicals diffuse and move from the catalyst body 10 toward the substrate 3 due to a transport phenomenon caused by a temperature gradient and a concentration gradient. This situation is indicated by reference numeral 37b in FIG.

  On the other hand, from the silane gas supply source 17a which is the second source gas, the silane gas flow meter 18a, the second source gas supply pipe 25b, the vacuum source insulator source gas connection pipe 28, and the second source gas ejection hole pipe 26b. The silane gas supplied via is ejected from the second source gas ejection hole 19b. The jetted silane gas diffuses and moves between the casings 20 due to a transport phenomenon caused by a temperature gradient and a concentration gradient. In addition, the silane gas injected from the 2nd source gas injection hole 19b is shown as the code | symbol 35b in FIG.

The H radical and NH ₂ radical generated by the high temperature catalyst body 10 set at 1800 ° C. and the silane gas ejected from the second source gas ejection hole 19b diffuse and move inside the reaction vessel 1, but FIG. As shown, contact mixing occurs. This contact mixing area is indicated by reference numeral 33b in FIG.

In the contact mixing region 33b, the second source gas S _i H ₄ and the atomic H and NH ₂ radicals cause a reaction represented by the following formula in the gas phase.
S _i H ₄ + H → S _i H ₃ + H _{2
S i H 3 + NH 2 →} S i H 2 (NH 2) + H
NH ₃ + H → NH ₂ + H ₂
As a result, a large number of S _i H ₂ (NH ₂ ) radicals known as precursors for forming the S _i N _x film are generated. In addition, the movement of the S _i H ₂ (NH ₂ ) radical having the characteristic of movement due to the transport phenomenon caused by the temperature gradient and the concentration gradient is indicated by an arrow 38b in FIG.
As a result, the S _i H ₂ (NH ₂ ) radical reaches the surface of the substrate 3, and a high-quality S _i N _x film using the S _i H ₂ (NH ₂ ) radical as a precursor is formed.
Note that the deposition rate of the S _i N _x film depends on the concentrations of the S _i H ₄ , the atomic H, and the NH ₂ radicals of the second source gas. It is preferable to perform optimization by grasping the relationship between the speed, the pressure condition, and the supply amounts of the first and second source gases.

Next, when a predetermined film formation time elapses in the film formation, for example, 1 minute, a hydrogen source 23a and an ammonia supply source 23b, which are first source gas supply sources, and a second source gas, not shown, are provided. The valve 17a (not shown) is closed to stop the supply of the source gas. Then, the output of the catalyst heating power source 6 is reduced to zero.
Here, the film forming time is the elapsed time from the time when the temperature of the catalyst body 10 is operated at 1800 ° C. In the case where the film forming time is accurately performed, it is preferable to use a shutter mechanism that can be opened and closed in the vicinity of the substrate 3.
Thereafter, a substrate moving door (not shown) between the reaction vessel 1 and an unloading chamber (not shown) is opened, and the substrate 3 is moved from the substrate holding means 3a to the unloading chamber (not shown) by a substrate moving device (not shown). Then, the substrate moving door is closed.

Since the substrate 3 to be deposited has been removed from the substrate holding means 3a of the reaction vessel 1, the substrate 3 is newly moved from a load chamber (not shown). As described above, the substrate 3 prepared in advance in a load chamber (not shown) is opened, the substrate moving door between the load chamber and the reaction vessel 1 is opened, and the substrate 3 is mounted on the substrate holding means 3a by the substrate moving device (not shown). Put. Then, a substrate moving door (not shown) is closed.
Then, the above-described film forming process is repeated for a predetermined number of times, for example, 1000 substrates.

According to the configuration of the catalytic CVD apparatus according to the second embodiment of the present invention, the casing 20 is installed as a partition between the second source gas ejection hole 19b and the catalyst body 10, and the second source gas ejection The state in which the temperature of the catalyst body 10 (1800 ° C.) is significantly higher than the temperature in the vicinity of the hole 19b is maintained, and the partial pressure at the time of supplying the mixed gas of the first raw material hydrogen gas and ammonia gas (for example, , 20 Pa) is kept higher than the partial pressure (for example, 10 Pa) at the time of supplying the silane gas of the second source gas.
As a result, the contact between the catalyst body 10 and the _Si H ₄ gas molecules that cause the tungsten silicide of the catalyst body 10 is prevented.
That is, when (i) S _i H ₄ gas molecules do not collide with other molecules and move while colliding with surrounding walls (molecular flow), they collide with the wall of the casing 20 and the catalyst body 10 (B) When S _i H ₄ gas molecules move by diffusion based on the temperature gradient, the diffusion force (thermophoretic force) based on the temperature gradient works from the higher temperature side to the lower temperature side. _i H ₄ gas molecules move away from the catalyst body 10. (c) When moving by diffusion based on the concentration gradient, the partial pressure around the catalyst body is larger than the partial pressure around the second source gas ejection holes 19 b. Therefore, the movement due to the concentration gradient moves in a direction away from the catalyst body 10. As a result, contact between Si atoms and tungsten does not occur, so that tungsten silicidation does not occur in the catalyst body 10. That is, deterioration and disconnection of the catalyst body 10 due to tungsten silicidation do not occur.

  According to the configuration of the catalytic CVD apparatus according to the second embodiment of the present invention, the problem of degradation of the catalytic body function and disconnection due to tungsten silicidation of the catalytic body of the conventional catalytic CVD and catalytic CVD method can be easily solved. . That is, when the catalytic CVD apparatus is applied to mass production facilities for products such as solar cells and various semiconductor devices, it can contribute to a significant improvement in apparatus operation rate and product yield.

(Third embodiment)
Next, a catalytic CVD apparatus and a catalytic CVD method according to the third embodiment of the present invention will be described with reference to FIGS. 9 and 10, the same members as those shown in FIGS. 1 to 8 are denoted by the same reference numerals, and redundant description is omitted.
In the drawings shown below, the scale of each member may be different from the actual one for convenience of explanation. In addition, the scale may be different between the drawings.

FIG. 9 is a schematic cross-sectional view for explaining the configuration of a catalytic CVD apparatus according to the third embodiment of the present invention. FIG. 10 is a schematic perspective view for explaining a ladder-type second source gas ejection pipe used in the catalytic CVD apparatus according to the third embodiment of the present invention.
First, the configuration of the catalytic CVD apparatus according to the third embodiment of the present invention will be described.
The main constituent members of the catalytic CVD apparatus according to the third embodiment of the present invention are, as shown in FIG. 9, a first source gas ejection box 26a installed on the inner wall of the reaction vessel 1 facing the substrate holding means 3a. Are arranged in the order of a later-described catalyst body space 10aa installed next to the second body gas ejection pipe 26bb described later installed next to the catalyst body space 10aa. Then, between the second source gas ejection pipe 26bb and the substrate 3 placed on the substrate holding means 3a, the radicals or decomposition species generated in the catalyst body space 10aa and the second source gas are mixed in contact. A region 33a is provided.

In FIG. 9, the code | symbol 21 is a partition. The partition wall 21 is made of a metal flat plate, and is electrically connected to the reaction vessel 1, that is, kept in a grounded state. The partition wall 21 includes an opening 20dd, which will be described later, serving as a vent. The partition wall 21 has a catalyst body 10 installed in parallel to the substrate holding surface of the substrate holding means 3a and a second source gas to be described later for ejecting a second source gas arranged in one plane parallel to the substrate holding surface. It arrange | positions in the position pinched | interposed into the ejection pipe 26bb.
Reference numeral 20dd denotes an opening. The opening 20 dd is a through hole provided in the partition wall 21 and allows the radicals or decomposition species generated by the first source gas and the catalyst body 10 to pass therethrough. The shape of the opening 20dd can be arbitrarily selected, but a circular shape, a rectangular shape, a long hole shape, or a slit shape is preferable for ease of processing. Moreover, although the aperture ratio of the opening 20dd can be arbitrarily selected, the aperture ratio is preferably set to be larger than about 30% in order to allow radicals or decomposition species generated in the catalyst body 10 to pass therethrough. Here, for example, 50%.

Reference numeral 26bb denotes a second source gas ejection pipe. The second source gas ejection pipe 26bb is provided with a second source gas ejection hole 19 through which the second source gas is ejected. The second source gas ejection pipe 26bb is electrically ungrounded. The shape of the second source gas ejection pipe 26bb is arbitrarily selected, such as a U-shape, a W-shape, or a zigzag shape, but a communication tube is preferable. Here, the second source gas ejection pipe 26bb is formed in a ladder shape as shown in FIG. 10, insulated from the reaction vessel 1 by the source gas connection pipe 28 made of an insulator for vacuum equipment, and is electrically ungrounded. Keep on. That is, the second source gas ejection pipe 26bb is electrically ungrounded.
Reference numeral 10aa denotes a catalyst body space. The catalyst body space 10aa is a space sandwiched between the first source gas ejection box 26a and the partition wall 21, and the catalyst body 10 is installed in the space. The catalyst body 10 is set parallel to the substrate 3 placed on the substrate holding means 3a. As shown in FIG. 10, a first source gas ejection hole 19 a attached to the first source gas ejection box 26 a is arranged in parallel with the catalyst body 10. Further, an opening 20 dd of the partition wall 21 is arranged in parallel to the catalyst body 10.
The first source gas ejection box 26a includes a hydrogen gas flow meter 24a, a hydrogen gas supply source 23a, an ammonia gas flow meter 24b, an ammonia gas supply source 23b, and a nitrogen gas via a first source gas supply pipe 25a. The flow meter 24c and the nitrogen supply source 23c communicate with each other.

The features of the configuration of the catalytic CVD apparatus according to the third embodiment of the present invention are as follows. The partition wall 21 is provided with an opening 20dd serving as a vent, and the catalyst body 10 installed in parallel to the substrate holding surface of the substrate holding means 3a and the second plate arranged in one plane parallel to the substrate holding surface. The catalyst body 10 is disposed in a plane parallel to the partition wall 21 having the opening 20dd and the substrate holding surface, and is disposed at a position sandwiched by the second source gas ejection pipe 26bb for ejecting the source gas. The second source gas ejection pipe 26bb is disposed at a position sandwiched between the first source gas ejection holes 19a for ejecting the first source gas, and the partition 21 having the opening 20dd and the substrate holding means It is arranged at a position sandwiched between the substrate holding surfaces 3a.
The partition wall 21 is made of a metal plate material that is electrically grounded, has a plurality of vent holes 20dd, and the second source gas ejection pipe 26bb is electrically ungrounded. And a second raw material gas injection hole 19b for injecting the second raw material gas, and a high frequency power source 60 used for plasma generation is connected. It is characterized by that.

Then, using the catalytic CVD apparatus shown in FIGS. 9 and 10, take a-S _i film is a passivation film heterojunction solar cells, the following description will discuss the film forming method.
Here, take a-S _i film is a passivation film heterojunction solar cell as an example, the hydrogen (H ₂₎ as the first material gas, silane as the second source gas (S i _{H 4)} The film forming method will be described, but it should be understood that the catalytic CVD apparatus and the catalytic CVD method according to the third embodiment of the present invention are not limited to the formation of the a- _Si film.

For example, when forming a p-type a-Si film of a solar cell, a mixed gas of hydrogen (H ₂ ) and diborane (B ₂ H ₆ ) is used as the first source gas, and silane (S _i H ₄ ) is preferred.
For example, when forming an n-type a-Si film of a solar cell, a mixed gas of hydrogen and phosphine (PH ₃ ) is used as the first source gas, and silane (S _i H ₄ ) is used as the second source gas. It is good to choose.
Further, for example, when an amorphous silicon carbide (a-SiC) film is formed, hydrogen (H ₂ ), methane (CH ₄ ), ethane (C ₂ H ₆ ), ethylene (as the first source gas) C ₂ H ₆ ) and silane (S _i H ₄ ) may be selected as the second source gas.
For example, when an amorphous silicon germanium (a-SiGe) film is formed, a mixed gas of hydrogen (H ₂ ) and germane (GeH ₄ ) is used as the first source gas, and silane is used as the second source gas. It is better to select (S _i H ₄ ).
For example, in the case of forming a silicon oxide (S _i O ₂ ) film, a mixed gas of oxygen (O ₂ ) and nitrous oxide (N ₂ O) is used as the second source gas as the first source gas. It is preferable to select silane (S _i H ₄ ).

For example, in the case of forming an S _i CN film as a sealing film of an organic EL device, a mixed gas of hydrogen (H ₂ ) and ammonia (NH ₃ ) is used as the second raw material as the first raw material gas. is good pick monomethyl silane _{(CH 3} S i _{H 3)} as a gas.

Here, the substrate 3 is, for example, glass having a size: 150 mm × 150 mm × thickness 0.63 mm.
A substrate moving door between the load chamber and the reaction vessel 1 is opened for a substrate 3 prepared in advance in a load chamber (not shown), and the substrate 3 is placed on the substrate holding means 3a by a substrate moving device (not shown). Then, the substrate moving door (not shown) is closed.

Next, a vacuum pump (not shown) is operated, and the pressure inside the reaction vessel 1 is once lowered to a degree of vacuum, for example, about 2.67 × 10 ⁻⁴ Pa (2 × 10 ⁻⁶ Torr).
Next, the flow rate of the hydrogen gas is set to about 10 sccm to 200 sccm, for example, 50 sccm by the flow meter 24a of the hydrogen gas that is the first source gas.
Then, using a pressure gauge (not shown) and a vacuum pump (not shown), the internal pressure of the reaction vessel 1 is set to about 1.33 Pa to 30 Pa (0.01 Torr to 0.225 Torr), for example,
Set to 20 Pa (150 mTorr) and maintain.
Next, after confirming that the pressure of the hydrogen gas that is the first source gas is maintained at 20 Pa, while gradually opening an outlet valve (not shown) of the flow meter 17a of the silane gas that is the second source gas, When the value of a pressure gauge (not shown) inside the reaction vessel 1 reaches 30 Pa while slightly increasing the flow rate of the second source gas, the flow rate of the second source gas is kept constant at that value. That is, the partial pressure of the first source gas (hydrogen) is set to 20 Pa (150 mTorr), the partial pressure of the second source gas (silane) is set to 10 Pa, and the total pressure P (20 Pa + 10 Pa) is set to 30 Pa (225 mTorr). maintain.
Note that the above-described adjustment operation of the first source gas and the second source gas may be automatically performed by a computer control method using a solenoid valve, a digital flow rate control device, or the like (not shown).
Next, electric power is supplied from the catalyst heating power source 6 to the catalyst body 10 through the power supply lines 7a and 7b and the vacuum current introduction terminals 5a and 5b, respectively, to generate heat.
The temperature of the catalyst body 10 is in the range of 1000 ° C. to 1900 ° C., for example, 1700 ° C. In addition, the data grasped in advance, that is, the relationship between the output of the catalyst heating power source 6, the temperature of the catalyst body 10, and the pressure of the reaction vessel 1 is utilized.
The temperature of the substrate 3 is set in the range of 80 ° C. to 350 ° C., for example, 150 ° C. and maintained.

The H ₂ gas ejected from the first source gas ejection hole 19 a diffuses while contacting the catalyst body 10. The H ₂ gas that has contacted the high temperature catalyst body 10 set at 1700 ° C. causes a catalytic reaction. That is, the H ₂ molecule that has contacted the surface of the catalyst body 10 is separated into two atomic H and adsorbed on the catalyst body 10 (dissociative adsorption). The atomic H adsorbed on the surface of the catalyst body 10 is released into the gas phase while being separated (thermal desorption) because the catalyst body 10 is at a high temperature. Here, here, the released atomic H is called a radical or a decomposed species.
The released atomic H moves from the catalyst body 10 toward the substrate 3 due to a transport phenomenon caused by a temperature gradient and a concentration gradient. That is, it diffuses and moves around the second source gas ejection pipe 26bb from the inside of the catalyst body space 10aa through the opening 20dd of the partition wall 21.
The situation in which the H radicals diffuse and move is schematically indicated by reference numeral 37aa in FIG.

On the other hand, from the silane gas supply source 17a which is the second source gas, the silane gas flow meter 18a, the second source gas supply pipe 25b, the vacuum source insulator source gas connection pipe 28 and the second source gas ejection hole pipe 26bb. The silane gas supplied via is ejected from the second source gas ejection hole 19b. The ejected silane gas diffuses and moves due to a transport phenomenon caused by a temperature gradient and a concentration gradient.
The movement state of the silane gas ejected from the second source gas ejection hole 19b is schematically shown as reference numeral 35bb in FIG.

The H radical generated by the high-temperature catalyst body 10 set at 1700 ° C. and the silane gas ejected from the second raw material gas ejection hole 19b diffuse and move inside the reaction vessel 1, but the contact mixing region shown in FIG. At 33a, contact mixing occurs.
In the contact mixing region 33a, a chemical reaction represented by the following formula occurs.
S _i H ₄ + H → H ₂ + S _i H ₃
Note that the reaction between S _i H ₄ and H occurring in the contact mixing region 33a is schematically shown in FIG.
In the above reaction process, the S _i H ₃ radical has a feature that it has a long lifetime and moves by a transport phenomenon due to a temperature gradient and a concentration gradient, and is a good precursor for the formation of a silicon-based thin film. Move, reach and deposit. The S _i H ₃ radical, which is indicated by the reference numeral 38a in FIG. 9, is a precursor that forms a high-quality film. Therefore, the a-Si film formed on the substrate 3 is a high-quality film.
In addition, since the film-forming speed of the a-Si film depends on the concentration of the source gas S _i H ₄ and the atomic H, when the film is formed at a particularly high speed, the film-forming speed and the pressure are set in advance. It is preferable to perform optimization by grasping the relationship between the conditions, the supply amount of the raw material gas, and the flow rate ratio.

Next, when a predetermined deposition time elapses, for example, for 1 minute in the above-described film formation, a valve (not shown) of the first source gas supply source 23a and a valve (not shown) of the second source gas supply source 17a are closed. , Stop supplying the source gas. Then, the output of the catalyst heating power source 6 is reduced to zero.
Here, the film forming time is an elapsed time from the time when the temperature of the catalyst body 10 is operated at 1700 ° C. In the case where the film forming time is accurately performed, it is preferable to use a shutter mechanism that can be opened and closed in the vicinity of the substrate 3.
Thereafter, a substrate moving door (not shown) between the reaction vessel 1 and an unloading chamber (not shown) is opened, and the substrate 3 is moved from the substrate holding means 3a to the unloading chamber (not shown) by a substrate moving device (not shown). Then, the substrate moving door (not shown) is closed.

Since the substrate 3 to be deposited has been removed from the substrate holding means 3a of the reaction vessel 1, the substrate 3 is newly moved from a load chamber (not shown). As described above, the substrate 3 prepared in advance in a load chamber (not shown) is opened, the substrate moving door between the load chamber and the reaction vessel 1 is opened, and the substrate 3 is mounted on the substrate holding means 3a by the substrate moving device (not shown). Put. Then, the substrate moving door (not shown) is closed.
Then, the above-described film forming process is repeated for a predetermined number of times, for example, 1000 substrates.

According to the configuration of the catalytic CVD apparatus according to the third embodiment of the present invention, the partition wall 21 having the opening 20dd is installed between the second source gas ejection hole 19b and the catalyst body 10, and the second source gas is provided. The state in which the temperature of the catalyst body 10 (1700 ° C.) is remarkably higher than the temperature in the vicinity of the ejection hole 19b is maintained, and the partial pressure at the time of supply of the hydrogen gas of the first source gas that contacts the catalyst body 10 ( For example, since 20 Pa) is kept higher than the partial pressure (for example, 10 Pa) at the time of supplying the silane gas of the second source gas, the diffusion movement direction of the gas molecules due to the concentration gradient starts from the catalyst body 10. It faces the second source gas ejection pipe 26bb.
As a result, the contact between the catalyst body 10 and the _Si H ₄ gas molecules that cause the tungsten silicide of the catalyst body 10 is prevented.
That is, (i) When the S _i H ₄ gas molecules move while colliding with the surrounding wall without colliding with other molecules (molecular flow), it collides with the wall of the partition wall 21, the catalyst 10 can not be moved in the direction, (b) if S _i H ₄ gas molecules migrate by diffusion based on the temperature gradient, the diffusion force based on the temperature gradient (thermal migration force) acts from the high temperature side to the low side, S _i The H ₄ gas molecules move in a direction away from the catalyst body 10. (C) When the S _i H ₄ gas molecules move by diffusion based on the concentration gradient, the partial pressure around the catalyst body 10 is the second raw material gas ejection hole. Since it is larger than the partial pressure around 19 b, the movement due to the concentration gradient moves in a direction away from the catalyst body 10. As a result, contact between Si atoms and tungsten does not occur, so that tungsten silicidation does not occur in the catalyst body 10. That is, deterioration and disconnection of the catalyst body 10 due to tungsten silicidation do not occur.

  According to the configuration of the catalytic CVD apparatus according to the third embodiment of the present invention, the problem of degradation of the catalytic body function and disconnection due to tungsten silicidation of the catalytic body of the conventional catalytic CVD and catalytic CVD method can be easily solved. . That is, when the catalytic CVD apparatus is applied to mass production facilities for products such as solar cells and various semiconductor devices, it can contribute to a significant improvement in apparatus operation rate and product yield.

(Fourth embodiment)
Next, a catalytic CVD apparatus according to a fourth embodiment of the present invention and a self-cleaning method of the catalytic CVD apparatus will be described with reference to FIGS. 1 to 4 and FIG. Note that the catalytic CVD apparatus according to the fourth embodiment of the present invention also uses the members used in the catalytic CVD apparatus according to the first to third embodiments of the present invention.
The self-cleaning method of the catalytic CVD apparatus is used when removing the film adhering to the internal member of the reaction vessel 1 of the catalytic CVD apparatus in which an a-Si film, a SiNx film or the like is formed. In general, mass production apparatuses such as solar cells and semiconductor devices are used as indispensable steps for improving product yield and productivity.
In FIG. 11, the same members as those shown in FIG. 1 to FIG.
In the drawings shown below, the scale of each member may be different from the actual one for convenience of explanation. In addition, the scale may be different between the drawings.

First, the configuration of the apparatus will be described. FIG. 11 is a schematic cross-sectional view for explaining the configuration of a catalytic CVD apparatus and a self-cleaning method of the catalytic CVD apparatus according to the fourth embodiment of the present invention.
In Figures 1-4 and 11, reference numeral 17b is a NF ₃ gas supply source. NF ₃ gas supply source 17b supplies a NF ₃ gas as an etching gas, through the NF ₃ gas flow meter 18b to the source gas supply pipe 25b.
Reference numeral 18b is an NF ₃ gas flow meter. NF ₃ gas flowmeter 18b is set to an arbitrary flow rate preselected flow rate of NF ₃ gas-gas supplied from the NF ₃ gas supply source 17b, and supplies the second source gas supply pipe 25b. Here, the flow rate of the NF ₃ gas flow meter 18b can be set to an arbitrary flow rate in the range of 1 sccm to 100 sccm.
Reference numeral 23c is an _{N 2} gas supply source. The N ₂ gas supply source 23c supplies N ₂ gas to the source gas supply pipe 25b via the N ₂ gas flow meter 24c.
Reference numeral 24 c is an N ₂ gas flow meter. N ₂ gas flow meter 24c is set to an arbitrary flow rate preselected flow rate of N ₂ gas supplied from N ₂ gas supply source 23c, and supplies the second source gas supply pipe 25b. Here, the flow rate of the flow meter 24c of _{N 2} gas can be set to any flow rate in the range of 10Sccm～200sccm.

1 to 4 and 11, the second source gas ejection pipe 26 b is electrically insulated from the reaction vessel 1 by a vacuum device insulating source gas connection pipe 28 and is kept in a non-grounded state.
The second source gas ejection pipe 26b is installed between the first casing 20a and the second casing 20b and between the second casing 20b and the third casing 20c.
In addition, the second raw material gas ejection pipe 26b receives high-frequency power generated by a high-frequency power source 60 described later via an impedance matching device 61, a power distributor 62, a high-frequency current introduction terminal 63, and a vacuum coaxial cable 65. Applied from a high frequency power supply point 66. In this case, a high-frequency electric field is generated between the second source gas ejection pipe 26b and the casing 20, and the NF ₃ gas of the second source gas ejected from the second source gas ejection hole 19b is converted into plasma. Is done. As a result, F radicals are generated, and the film adhering to the internal member of the reaction vessel is removed by etching (referred to as self-cleaning).

1-4 and FIG. 11, the code | symbol 60 is a high frequency power supply. The high-frequency power supply 60 is selected in the frequency range of 10 MHz to 300 MHz at which low pressure gas can be easily converted into plasma. Here, 13.56 MHz is selected because the device price is low.
Reference numeral 61 denotes an impedance matching unit. The impedance matching unit 61 matches the output impedance of the high frequency power supply 60 with the impedance of the generated plasma. When the alignment is adjusted, the reflected wave from the plasma side of the high frequency power supplied from the high frequency power supply 60 to the second source gas ejection pipe 26b is reduced. In addition, since the property of the traveling wave and reflected wave as electromagnetic waves appears in the high frequency power, the traveling wave output from the high frequency power source 60 is adjusted to the maximum and the reflected wave returning is adjusted to the minimum by using the impedance matching unit 61. It is necessary to.
Reference numeral 62 denotes a power distributor. The power distributor 62 distributes the output of the high frequency power supply 60. Here, it is divided into two and transmitted to the coaxial cables 67a and 67b, respectively.
Reference numeral 63 denotes a high-frequency current introduction terminal. The high-frequency current introduction terminal 63 is a vacuum device current introduction terminal with low transmission loss of high-frequency power.
Reference numeral 65 denotes a vacuum power transmission conductor. The vacuum power transmission conductor 65 is a coaxial cable or a conductive wire.
Reference numeral 66 denotes a high-frequency power supply point. The high-frequency power supply point 66 is a connection point between the second source gas ejection pipe 26b and the vacuum power transmission conductor 65, and the output of the high-frequency power source 60 is the impedance matching device 61, the power distributor 62, and the coaxial cables 67a and 67b. The high-frequency current introduction terminal 63 and the vacuum power transmission conductor 65 are supplied.

When the output of the high frequency power supply 60 is supplied to the second source gas jet pipe 26b, a high frequency electric field is generated between the second source gas jet pipe 26b and the housing 20, and the second source gas jet pipe 26b For example, when NF ₃ gas is ejected, the NF ₃ gas is turned into plasma. When the NF ₃ gas is turned into plasma, a large number of F radicals are generated, and the silicon-based film adhered to the internal members of the reaction vessel 1 such as the second source gas ejection pipe 26b, the housing 20, and the substrate holding means 3a. And a highly volatile S _i F ₄ is discharged outside the reaction vessel 1.
FIG. 11 shows a plasma generation region of NF ₃ gas by reference numeral 70a. Further, movement due to diffusion of F radicals is indicated by reference numeral 70b.

Next, a vacuum pump (not shown) is operated to lower the pressure inside the reaction vessel 1 to a vacuum level, for example, about 2.67 × 10 ⁻⁴ Pa (2 × 10 ⁻⁶ Torr).
Then, the flow rate of _{N 2} gas flow meter 24c of _{N 2} gas, about 5Sccm～500sccm, for example, set to 50 sccm.
Then, using a pressure gauge (not shown) and a vacuum pump (not shown), the internal pressure of the reaction vessel 1 is set to about 1.33 Pa to 50 Pa (0.01 Torr to 0.375 Torr), for example,
Set to 40 Pa (300 mTorr).
Next, after confirming that the pressure of the N ₂ gas as the first source gas is maintained at 40 Pa, the outlet valve (not shown) of the flow meter 18b of the NF ₃ gas as the second source gas is opened little by little. However, while the flow rate of the second source gas is slightly increased, when the value of a pressure gauge (not shown) inside the reaction vessel 1 reaches 53 Pa, the value is kept constant. That is, the partial pressure of the first raw material gas (N ₂ gas) is 40 Pa (300 mTorr), the partial pressure of the second raw material gas (NF ₃ gas) is 13 Pa, and the total pressure P (40 Pa + 13 Pa) is 53 Pa (400 mTorr). Set to and maintain.
Note that the above-described adjustment operation of the first source gas and the second source gas may be automatically performed by a computer control method using a solenoid valve, a digital flow rate control device, or the like (not shown).
Next, high-frequency power is supplied from the high-frequency power source 60 to the second source gas ejection pipe 26b through the impedance matching device 61, the power distributor 62, the high-frequency current introduction terminal 63, and the high-frequency power supply point 66.
The temperature of the board | substrate 3 is set to 100 degreeC in the range of 80 to 200 degreeC, for example, and is maintained.

When the output of the high frequency power supply 60 is supplied to the second source gas jet pipe 26b, a high frequency electric field is generated between the second source gas jet pipe 26b and the housing 20, and the second source gas jet pipe 26b The ejected NF ₃ gas is turned into plasma. When the NF ₃ gas is turned into plasma, a large number of F radicals are generated, and the silicon-based film adhered to the internal members of the reaction vessel 1 such as the second source gas ejection pipe 26b, the housing 20, and the substrate holding means 3a. And a highly volatile S _i F ₄ is discharged outside the reaction vessel 1. As a result, the film adhering to the member surface inside the reaction vessel 1 is removed.
The self-cleaning time may be set in consideration of the thickness of the silicon film attached to the internal member of the reaction vessel 1. For example, when the film forming process and the self-cleaning process are alternately performed in time, the self-cleaning process is performed after the estimated film thickness of the film deposited on the internal member of the reaction vessel 1 in the film forming process becomes about 1 μm. In this case, the time of the self-cleaning process using NF ₃ gas may be about 60 seconds to 90 seconds.

The self-cleaning method using the catalytic CVD apparatus of the fourth embodiment according to the present invention has the following effects.
According to the configuration of the catalytic CVD apparatus according to the fourth embodiment of the present invention, the housing 20 is installed as a partition wall between the second source gas ejection hole 19b and the catalyst body 10, and the second source gas ejection The state in which the partial pressure in the vicinity of the catalyst body 10 is higher than the partial pressure in the vicinity of the hole 19b is maintained.
As a result, etching of the catalyst body 10 with fluorine is prevented, so that the catalyst body 10 is not thinned and deteriorated.
That is, (a) when the fluorine radical moves while colliding with surrounding walls without colliding with other molecules (molecular flow), it collides with the wall of the casing 20 and moves in the direction of the catalyst body 10. (B) When the fluorine radicals move by diffusion based on the concentration gradient, the partial pressure around the catalyst body is larger than the partial pressure around the second source gas ejection hole 19b, and therefore the movement due to the concentration gradient is from the catalyst body 10. Move away. (C) In a situation where the fluorine gas is turned into plasma, N ₂ gas is ejected from the first source gas ejection hole 19a and purges the surface of the catalyst body 10 which is not at a high temperature, so that fluorine radicals cannot contact.
As a result, contact between the fluorine radical and tungsten does not occur, so that the catalyst body 10 is not thinned and deteriorated by the fluorine radical.

  By using the catalytic CVD apparatus according to the fourth embodiment of the present invention, the film formation by the catalytic CVD method and the self-cleaning method of the catalytic CVD apparatus by the plasma can be used together, and the solar cell and various semiconductor devices of the catalytic CVD apparatus In application to mass production facilities such as products, it can contribute to a significant improvement in equipment availability and product yield.

1 ... reaction vessel,
2a, 2b... First and second exhaust holes,
3 ... substrate
3a ... substrate holding means,
6 ... Power source for heating the catalyst body,
10 ... catalyst body,
10aa ... catalyst body space,
19a ... 1st source gas ejection hole,
19b ... second source gas ejection hole,
20 ... Case,
20d ... Vent,
20dd ... opening,
21 ... partition wall,
23a, a first source gas supply source, a hydrogen gas supply source,
24a... First source gas flow meter, hydrogen gas flow meter,
17a ... second source gas supply source, silane gas supply source,
18a ... Flow meter of second source gas, silane gas flow meter,
25a: first source gas supply pipe,
25b ... second source gas supply pipe,
26a ... first source gas ejection box,
26b, 26bb ... second source gas ejection pipe,
33a, 33b ... contact mixing region,
37a, 37aa, 37b ... radical movement,
Movement of 38a ··· _S i _{H 3} radical,
_{38b ··· S i H 2 (NH} 2) the movement of radical,
17b: NF ₃ gas supply source,
18b ... NF ₃ gas flow meter,
23c ... N ₂ gas supply source,
24c ... N ₂ gas flow meter,
60 ... high frequency power supply,
61 ... impedance matching unit,
62 ... Power distributor,
66: High frequency power supply point.

Claims (12)

A reaction vessel containing a substrate holding means on which a substrate to be deposited is placed and provided with an exhaust means, a raw material gas supply means for supplying a raw material gas to the reaction vessel, and a linear shape that causes a catalytic reaction to the raw material gas A catalyst body and power supply means for supplying power to the catalyst body to maintain the catalyst body at a predetermined high temperature, and supplying the source gas introduced into the reaction vessel from the source gas supply means from the power supply means In the catalytic CVD apparatus for performing film formation on the substrate placed on the substrate holding means by catalytic decomposition by the catalyst body heated to a high temperature by the generated electric power,
The source gas supply means includes a first source gas supply means for supplying a first source gas that is catalytically decomposed by the catalyst body maintained at a predetermined high temperature by the electric power supplied from the power supply means, and the catalyst. A second source gas supply means for supplying a second source gas that is not catalytically decomposed by the medium;
A region in which the first source gas is brought into contact with the catalyst body and the radical species or decomposition species and the second source gas are brought into contact and mixed with each other is defined by the substrate held by the substrate holding means and the catalyst body. A catalytic CVD apparatus characterized in that a partition wall provided with an opening is disposed between the catalyst body and a second source gas ejection hole for ejecting the second source gas. The partition includes an opening serving as a vent, and the catalyst body disposed in parallel to the substrate holding surface of the substrate holding means and the second source gas disposed in one plane parallel to the substrate holding surface. The catalyst body is disposed at a position sandwiched between the second raw material gas ejection pipes to be ejected, and the catalyst body has the first raw material gas disposed in a plane parallel to the partition wall having the opening and the substrate holding surface. The second source gas ejection pipe is arranged at a position sandwiched between the first source gas ejection holes to be ejected, and the second source gas ejection pipe is arranged at a position sandwiched between the partition having the opening and the substrate holding surface of the substrate holding means. The catalytic CVD apparatus according to claim 1, wherein: The partition wall is made of a metal plate that is electrically grounded, has a plurality of openings, and the second source gas ejection pipe is a metal ladder that is electrically ungrounded. And a second source gas ejection hole for ejecting the second source gas, and connected to an output terminal of a high frequency power source used for plasma generation. The catalytic CVD apparatus according to any one of claims 1 and 2. The partition is formed of a metal casing that is electrically grounded, the casing has an opening, and the first raw material that ejects the first source gas into the casing A gas source hole and the catalyst body are arranged, and a second source gas jet pipe for jetting the second source gas is electrically non-grounded and is arranged around the outside of the casing. The catalytic CVD apparatus according to claim 1, wherein the catalytic CVD apparatus is connected to an output terminal of a high-frequency power source used for plasma generation. The catalytic CVD apparatus according to any one of claims 1 to 4, wherein the opening of the partition wall has a circular shape, a rectangular shape, a long hole shape, or a slit shape. The first source gas is hydrogen (H ₂ ), nitrogen (N ₂ ), ammonia (NH ₃ ), phosphine (PH ₃ ), diborane (B ₂ H ₆ ), germane (GeH ₄ ), methane (CH ₃ ). ) And ethane (C ₂ H ₆ ). The catalytic CVD apparatus according to claim 1, wherein the gas contains at least one selected from ethane (C ₂ H ₆ ). The second source gas, silane _{(S i H} 4), selected from disilane _(S i2 _H 6), trisilane _(S i3 _H 8), monomethyl silane _{(CH 3} S i _{H 3)} and a fluorine-containing gas The catalytic CVD apparatus according to any one of claims 1 to 6, wherein the gas is a gas containing at least one kind. The second source gas ejection pipe is connected to an output terminal of a radio frequency power source that supplies radio frequency power for plasma generation, and has a second source gas ejection hole for ejecting a fluorine-containing gas. The catalytic CVD according to any one of claims 3 to 5, wherein the one source gas ejection hole communicates with a first source gas supply means for supplying nitrogen or an inert gas. apparatus. A catalytic CVD method using the catalytic CVD apparatus according to any one of claims 1 to 7, wherein a desired thin film is formed on a substrate placed on the substrate holding means.
Wherein the reaction vessel partial pressure P ₁ inside during the supply of the first source gas, is set high as compared to the partial pressure P ₂ at the time of supply of the second source gas, and the total pressure P, That is, P = P ₁ + P ₂ with PD product = 0.02 to 0.68 (where P is the unit Pa, D is the distance between the catalyst wire and the partition, and the unit is m) The contact between the catalyst body and the second raw material gas is suppressed by setting the flow range of the gas and radical species around the catalyst body to an intermediate flow in a state between a molecular flow and a viscous flow. The catalytic CVD method characterized by this. A plasma cleaning method used for self-cleaning of the catalytic CVD apparatus according to any one of claims 1 to 7, wherein self-cleaning is performed to remove a film attached to the internal member of the reaction vessel. In doing so, nitrogen gas or inert gas is ejected from the first source gas ejection hole, fluorine-containing gas is ejected from the second source gas ejection tube, and the second source gas ejection tube from the high-frequency power source. A self-cleaning method for a catalytic CVD apparatus, wherein electric power is supplied to generate fluorine radicals by converting the fluorine-containing gas into plasma, thereby self-cleaning the inside of the reaction vessel. When performing plasma cleaning for removing the film adhering to the inner member of the reaction vessel, the fluorine-containing gas ejected from the second source gas ejection pipe is NF ₃ , CF ₄ , C ₂ F ₆ , C _{2 F 8, SF 4, SF} 6, S 2 F 10, XeF 2, self-catalytic CVD apparatus according to claim 10, characterized in that a gas containing at least one selected from ClF _3, and _{O 2} Cleaning method. When performing the plasma cleaning for removing the film adhering to the internal member of the reaction vessel, the partial pressure P ₁ inside the reaction vessel at the time of supplying the first raw material gas is changed to the second raw material gas. set high as compared to the partial pressure _{P 2} at the time of supply, the total pressure P, i.e., _{P =} P 1 + _{P 2} a PD product = from 0.02 to 0.68 (however, the unit of P is Pa, D is The distance between the catalyst line and the partition wall, the unit of which is m), and the flow of gas and radical species around the catalyst body is an intermediate flow in a state between a molecular flow and a viscous flow. 12. The self-cleaning method for a catalytic CVD apparatus according to claim 10, wherein contact between the catalyst body and the fluorine radical is suppressed.

Images