JP2009021615A - Plasma cvd system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely prevent an inner electrode from becoming dirty and to enlarge a film forming region. <P>SOLUTION: Plasma spaces P are generated between a pair of electrodes 12 and 13 and a pair of electrodes 23 and 22 under ordinary pressure. Reactant gas is supplied to the respective plasma spaces P from supply sources 71 and 72. Metal-including gas is supplied to a part between two outlets 1b and 1b from which reactant gas passing through the two plasma spaces P and P is blown out from a supply source 80. In a straightening vane 31, a passage of convergence gas of blown-out reactant gas and metal content gas is formed to follow a face to be processed. The gas straightening vane 31 is put on a face facing all faces to be processed of two pairs of electrodes and is made to project outside from the electrodes on both outer sides in two pairs of electrodes. Exhaust mechanisms 91 and 92 are arranged outside. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plasma CVD apparatus for forming a metal-containing thin film on a substrate surface.

  There are the following methods for forming a metal-containing thin film on the surface of a substrate by plasma CVD.

(1) A method in which a mixed gas of an organometallic compound and oxygen is plasma-excited under normal pressure and then sprayed onto a substrate to form an oxide thin film.

(2) A method in which an oxygen gas is mixed with a metal-containing gas that has been plasma-excited under normal pressure, and the mixed gas is further plasma-excited to form a film on a substrate.

(3) A method in which a plurality of gases are separately plasma-excited under reduced pressure and mixed in the vicinity of the substrate to form a film.

  By the way, among the film-forming methods by the plasma CVD method described above, according to the film-forming methods (1) and (2), since the film is formed on the electrode (for plasma generation) itself in the plasma space, the gas is effectively used. Thus, a high film formation rate cannot be obtained. In addition, since a large amount of electrode deposits are generated, there is a drawback that the maintenance interval is shortened.

  On the other hand, according to the film forming method (3), since it is a decompression process, a lot of time is required for evacuation, and there is a problem that throughput is poor. Also, in the viscous flow region (normal pressure) where the influence of the gas flow is strong, even if multiple types of gas are simply concentrated and sprayed at the same location, each will flow separately as a laminar flow. The method cannot be adopted as it is.

  The present invention has been made in view of such circumstances, and can form a metal-containing thin film under normal pressure at a deposition rate that can be used industrially, and can also increase the maintenance interval. The purpose is to provide a device.

  The present invention is a plasma CVD apparatus using a metal-containing gas and a reaction gas that reacts with the metal-containing gas, an electrode that generates a plasma space at normal pressure, and a reaction gas supply source that supplies the reaction gas to the plasma space And a metal-containing gas supply source for supplying a metal-containing gas in the vicinity of a reaction gas outlet that has passed through the plasma space, and a direction in which a combined gas of the reaction gas and the metal-containing gas that has passed through the plasma space flows is controlled. An exhaust mechanism is provided, and the exhaust mechanisms are arranged on both sides of the merge point, so that the conductance of the flow channel far from the plasma space among the merge gas channels from the merge point to the exhaust mechanism is reduced. The first feature is that it is configured.

  According to the present invention, the following operational effects can be achieved.

  First, since the metal-containing gas reacts immediately when it is turned into plasma, it is consumed as deposits and reactant particles on the electrode during the plasma space, thereby reducing the film formation rate and reducing impurities in the thin film. Cause contamination. In addition, frequent maintenance is required.

  In contrast, in the present invention, the metal-containing gas is joined to the reactive gas that has become the active species by passing through the plasma space, and the active species and the metal-containing gas are contacted to react to form a film. In addition, the metal-containing gas can be used efficiently in the film formation reaction, and the generation of electrode deposits and impurities can be prevented. Therefore, the metal-containing thin film can be obtained at a high film formation rate, and the maintenance interval can be lengthened.

  The flow of the combined gas of the reaction gas and the metal-containing gas after passing through the plasma space is preferably a gas flow that flows along the surface to be processed.

  If it does in this way, it reacts one after another, mixing the gas which joined, and forms a thin film in the to-be-processed surface of a base material. Here, by creating the above flow, the time required for the mixed gas and the time required for the reaction are secured, and since the reaction is performed immediately on the base, it is preferentially consumed for forming the thin film. It will be. Accordingly, the deposition rate can be improved without wasting the metal-containing gas. In addition, if the to-be-processed surface of a base material is a plane, it is preferable to make the flow substantially parallel to the plane.

  As a method for realizing the gas flow of the combined gas as described above, there is a method in which exhaust control is performed by an exhaust mechanism so that the combined gas forms a gas flow that flows along the surface to be processed of the substrate. it can.

  It is preferable that the total flow rate of the introduction flow rates of the metal-containing gas and the reactive gas is substantially the same as the flow rate of the gas flow flowing along the surface to be processed of the substrate. Further, it is preferable to use oxygen, nitrogen, or hydrogen as the reaction gas.

  The plasma CVD apparatus of the present invention is a plasma CVD apparatus that uses a metal-containing gas and a reactive gas that reacts with the metal-containing gas, and includes two sets of electrodes that generate a plasma space at normal pressure, and reacts with each plasma space. A reaction gas supply source for supplying a gas; a metal-containing gas supply source for supplying a metal-containing gas between two outlets from which the reaction gas that has passed through the two plasma spaces is blown; and A gas rectifying plate that forms a flow path of a combined gas of the reaction gas and the metal-containing gas along the surface to be processed, and the gas rectifying plate covers all surfaces of the two sets of electrodes facing the surface to be processed. In addition, both ends of the gas rectifying plate protrude outwardly from the electrodes disposed on both outer sides of the two sets of electrodes, and are on both sides of the two reaction gas blowout ports separated from the combined gas flow path. Before Gas rectifying plate further exhaust system outside the opposite ends of the second characterized in that it is arranged.

  According to the plasma CVD apparatus of the present invention, the metal-containing gas is merged with the reactive gas that has become the active species by passing through the plasma space, and the active species and the metal-containing gas react to contact each other to form a film. As a result, the metal-containing gas is efficiently used for the film-forming reaction, and electrode deposits and impurities can be prevented from being generated. Therefore, the metal-containing thin film can be obtained at a high film formation rate, and the maintenance interval can be lengthened.

  Furthermore, by performing exhaust control so that the direction in which the combined gas flows is in the direction along the surface to be processed of the base material, the mixed gas reacts one after another while mixing, and a thin film is formed on the surface to be processed of the base material. To form. Here, by creating the above flow, the time required for the mixed gas and the time required for the reaction are secured, and since the reaction is performed immediately on the base, it is preferentially consumed for forming the thin film. It will be. The deposition rate can be improved without wasting metal-containing gas. If the surface to be processed is a plane, it is preferable to create a flow substantially parallel to the plane.

  When the exhaust mechanism is arranged only on one side, the side separating the flow path of the merged gas (flow path along the surface to be treated of the substrate) from the location where the reaction gas and the metal-containing gas that have passed through the plasma space merge It is preferable to arrange it on the side close to the plasma space.

  This arrangement shortens the flow of the activated gas in comparison with the flow created by the reactive gas activated through the plasma space and the flow created by the non-activated metal-containing gas. The seeds reach the surface to be treated after contacting and mixing with the flow of the metal-containing gas. This arrangement is effective for reaching the substrate surface while contacting the metal-containing gas without deactivating the activated gas.

  In the arrangement of the exhaust mechanism described above, there may be a case where entrainment of external air from the side where the exhaust mechanism is not provided becomes a problem. In order to prevent this, as in the first feature described above, exhaust mechanisms are arranged on both sides of the confluence, and the confluence gas flow path from the confluence to the exhaust mechanism is located on the side far from the plasma space. What is necessary is just to employ | adopt the structure that the conductance of a flow path becomes small. Thus, by creating a conductance difference between the two flow paths and using the flow path closer to the plasma space as the main flow, the active species contacts and mixes with the flow of the metal-containing gas and then enters the surface to be processed. To reach.

  It is preferable that the two plasma spaces of the second feature are symmetric and that the reaction gas supply amount is also equal.

  According to the second feature, by disposing plasma outlet gas outlets at both ends of the metal-containing gas, it is possible to prevent the entrainment of external air, and the active species are brought into contact with and mixed with the flow of the metal-containing gas. To reach the surface to be processed. That is, with the arrangement described above, the entrainment of external air is prevented by the naturally extruded gas flow, and the active species reaches the surface to be treated after contacting and mixing with the flow of the metal-containing gas.

  In the second feature, an exhaust mechanism is disposed on both sides of the combined gas flow path from the two reaction gas outlets, so that the gas flow along the surface to be treated can be positively controlled, or after the reaction. The gas can also be recovered.

  Also in the first feature, a gas rectifying plate may be provided to form a merged gas flow path along the surface to be processed of the substrate.

  Furthermore, it is possible to employ a configuration in which a ceramic porous gas rectifying plate is used and an inert gas is blown out from the gas rectifying plate. Since the mixed gas after joining the gas rectifying plate comes into contact with the gas rectifying plate, the reactant is likely to adhere to the gas rectifying plate. However, it is effective to prevent such adhesion by blowing out the inert gas from the gas rectifying plate. Examples of the inert gas include nitrogen, argon, helium and the like.

  Next, the present invention will be described in more detail.

First, under the pressure in the vicinity of the atmospheric pressure referred to in the present invention means a pressure under a pressure of 1.333 × 10 ^{4 to} 10.664 × 10 ⁴ Pa. Among them, easy pressure adjustment, is preferably in the range of ^{9.331 × 10 4 ~10.397 × 10 4} Pa for device configuration is simplified.

  Examples of the material of the electrode for generating plasma in the present invention include simple metals such as iron, copper, and aluminum, alloys such as stainless steel and brass, and intermetallic compounds. The electrodes preferably have a structure in which the distance between the plasma spaces (between the electrodes) is constant in order to avoid occurrence of arc discharge due to electric field concentration. A parallel plate type counter electrode is more preferable.

  In addition, the electrode for generating plasma (counter electrode) needs to have a solid dielectric disposed on at least one of the opposing surfaces of the pair. At this time, it is preferable that the solid dielectric and the electrode on the side to be installed are in close contact with each other and the opposite surface of the electrode in contact is completely covered. If there is a portion where the electrodes directly face each other without being covered by the solid dielectric, arc discharge is likely to occur therefrom.

  The solid dielectric may be in the form of a sheet or a film. The solid dielectric may be a film coated on the electrode surface by a thermal spraying method or the like. The thickness of the solid dielectric is preferably 0.01 to 4 mm. If the thickness of the solid dielectric is too thick, a high voltage may be required to generate discharge plasma, and if it is too thin, dielectric breakdown may occur during voltage application and arc discharge may occur.

  Examples of the solid dielectric include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, metal dioxide such as silicon dioxide, aluminum oxide, zirconium dioxide, and titanium dioxide, and double oxides such as barium titanate. It is done.

  The solid dielectric preferably has a relative dielectric constant of 2 or more (25 ° C. environment, the same applies hereinafter). Specific examples of the solid dielectric having a relative dielectric constant of 2 or more include polytetrafluoroethylene, glass, and metal oxide film. Further, in order to stably generate a high density discharge plasma, it is preferable to use a solid dielectric having a relative dielectric constant of 10 or more. The upper limit of the relative dielectric constant is not particularly limited, but about 18,500 is known as an actual material. Examples of the solid dielectric having a relative dielectric constant of 10 or more include a metal oxide film mixed with 5 to 50% by weight of titanium oxide and 50 to 95% by weight of aluminum oxide, or a metal oxide containing zirconium oxide. The thing which consists of a material film can be mentioned.

  In the present invention, the distance between the electrodes is appropriately determined in consideration of the thickness of the solid dielectric, the magnitude of the applied voltage, the purpose of using plasma, etc., but is preferably 0.1 to 5 mm. If the distance between the electrodes is less than 0.1 mm, it may not be sufficient to install with a gap between the electrodes, whereas if it exceeds 5 mm, it is difficult to generate a uniform discharge plasma. More preferably, the interval is 0.5 to 3 mm at which discharge is easily stabilized.

  An electric field such as a high frequency, a pulse wave, or a microwave is applied between the electrodes to generate plasma, but it is preferable to apply a pulse electric field, and in particular, the rise and / or fall time of the electric field is 10 μs or less. Certain pulsed electric fields are preferred. If it exceeds 10 μs, the discharge state tends to shift to an arc and becomes unstable, and it becomes difficult to maintain a high-density plasma state by a pulse electric field. Also, the shorter the rise time and fall time, the higher the ionization of the gas during plasma generation, but it is actually difficult to realize a pulsed electric field with a rise time of less than 40 ns. A more preferable range of the rise time and the fall time is 50 ns to 5 μs. The rise time here refers to the time during which the voltage (absolute value) increases continuously, and the fall time refers to the time during which the voltage (absolute value) decreases continuously.

  The electric field strength of the pulse electric field is 10 to 1000 kV / cm, preferably 20 to 300 kV / cm. When the electric field strength is less than 10 kV / cm, it takes too much time for processing, and when it exceeds 1000 kV / cm, arc discharge tends to occur.

  The frequency of the pulse electric field is preferably 0.5 kHz or more. If it is less than 0.5 kHz, the plasma density is low, and the process takes too much time. The upper limit is not particularly limited, but it may be a high frequency band such as 13.56 MHz that is commonly used and 500 MHz that is used experimentally. In consideration of ease of matching with the load and handling, 500 kHz or less is preferable. By applying such a pulse electric field, the processing speed can be greatly improved.

  Moreover, it is preferable that one pulse duration in the said pulse electric field is 200 microseconds or less, More preferably, it is 3-200 microseconds. If it exceeds 200 μs, it tends to shift to arc discharge. Here, one pulse duration means a continuous ON time of one pulse in a pulse electric field composed of repetition of ON and OFF.

In the present invention, any of oxygen, nitrogen, and hydrogen is used as a reaction gas that is plasma-excited. The metal-containing gas is not performed plasma excitation, TMOS Si-based organometallic gas such as (tetramethoxysilane) or TEOS _{(tetraethoxysilane), TiCl 2, Ti (O} -i-C 3 H 7) 4 Or Ti-based gas such as Al (CH ₃ ) ₃ , Al (Oi-C ₃ H ₇ ) ₃ , Al (O-Sec-C ₄ H ₉ ) _3, etc. Can do. Furthermore, an inert gas such as N ₂ or Ar, oxygen, or a gas such as H ₂ O may be mixed with the metal-containing gas as a carrier gas.

According to the present invention, it is possible to generate a discharge directly under atmospheric pressure between electrodes, and to realize a high-speed processing with a more simplified electrode structure, an atmospheric pressure plasma apparatus by a discharging procedure, and a processing technique. Can do. In addition, parameters relating to each thin film can be adjusted by parameters such as frequency, voltage, and electrode interval of the applied electric field.
Furthermore, selective excitation is possible by frequency control including the shape and modulation of the applied electric field, and the film formation rate of the specific compound can be selectively improved, and the purity of impurities and the like can be controlled.

According to the present invention, the metal-containing gas is merged with the reactive gas that has become an active species by passing through the plasma space, and the active species and the metal-containing gas are brought into contact with each other to form a film. A metal-containing gas is efficiently used for the film formation reaction, and electrode deposits and impurities can be prevented from being generated. Therefore, the metal-containing thin film can be obtained at a high film formation rate, and the maintenance interval can be lengthened.
By making the combined gas of the reaction gas and the metal-containing gas after passing through the plasma space flow along the to-be-treated surface of the substrate, the time required for mixing and the time required for the reaction is ensured, Since the reaction is performed on the immediate side of the substrate, it is preferentially consumed for forming a thin film. Therefore, the deposition rate can be further increased without wasting the metal-containing gas.

  Embodiments of the present invention and non-claimed reference embodiments will be described below with reference to the drawings.

<Reference Embodiment 1>
FIG. 1 is a diagram schematically showing a configuration of a reference embodiment of the present invention.

  The plasma CVD apparatus shown in FIG. 1 includes a counter electrode 1 composed of a voltage application electrode 2 and a ground electrode 3, a counter flat plate 4, a power source 6, a reactive gas supply source 7, a metal-containing gas supply source 8, an exhaust mechanism 9, and the like. Yes.

  The voltage application electrode 2 and the ground electrode 3 of the counter electrode 1 are arranged to face each other at a predetermined interval so as to be parallel to each other, and a plasma space P is formed between the pair of electrodes 2 and 3. Each surface of the voltage application electrode 2 and the ground electrode 3 is covered with a solid dielectric (not shown).

  The counter electrode 1 is provided with a gas inlet 1a and a gas outlet 1b. A reaction gas supply source 7 is connected to the gas introduction port 1 a, and the reaction gas can be supplied between the voltage application electrode 2 and the ground electrode 3. The voltage application electrode 2 and the ground electrode 3 constituting the counter electrode 1 are rectangular plate electrodes, and the shape of the gas outlet 1b is a rectangle elongated in the depth direction of the drawing.

  The counter flat plate 4 is provided on the side of the ground electrode 3 of the counter electrode 1. The counter flat plate 4 is disposed in a state of facing the ground electrode 3 with a predetermined interval, and a gas introduction path 5 is formed between the counter flat plate 4 and the ground electrode 3. The gas introduction path 5 is supplied with a metal-containing gas from a metal-containing gas supply source 8 so that the supplied metal-containing gas merges with the reaction gas after passing through the plasma space P blown from the gas outlet 1b. It has become.

  The counter flat plate 4 is a flat plate having the same shape (rectangle) and dimensions as the voltage application electrode 2 and the ground electrode 3 of the counter electrode 1, and the outlet shape of the gas introduction path 5 is the same as the gas outlet 1 b of the counter electrode 1. It is a long and narrow rectangle in the depth direction. The parallel plate 4 may be made of metal or insulating material.

The exhaust mechanism 9 is disposed on the side of the voltage application electrode 2 of the counter electrode 1 and forces the gas between the counter electrode 1 and the counter flat plate 4 and the substrate S in the same direction (left side in FIG. 1). Exhaust. For example, a blower or the like is used for the exhaust mechanism 9.

In the plasma CVD apparatus having the above structure, the substrate S is placed at a position facing the gas outlet 1b of the counter electrode 1 and the outlet of the gas introduction path 5, and then the counter electrode 1 and the counter flat plate 4 are connected by the exhaust mechanism 9. The substrate S is forcibly evacuated in one direction, and further supplied with a metal-containing gas (for example, TMOS, TEOS, etc.) from the metal-containing gas supply source 8 to the gas introduction path 5, A reactive gas (for example, O ₂ or the like) is supplied from a reactive gas supply source 7 to the ground electrode 3. In this state, an electric field (pulse electric field) from the power source 6 is applied between the voltage application electrode 2 and the ground electrode 3 to generate a plasma space P between the voltage application electrode 2 and the ground electrode 3, and the reaction gas Is excited by plasma. The reaction gas (excited state) that has passed through the plasma space P and the metal-containing gas that has passed through the gas introduction path 5 are blown out toward the substrate S. Here, in this embodiment, forced exhaust is performed in one direction by the exhaust mechanism 9, so the combined gas of the reaction gas that has passed through the plasma space P and the metal-containing gas blown out from the gas introduction path 5 is mixed uniformly. In this state, the gas flow is substantially parallel to the surface to be processed of the substrate S, and flows in one direction toward the arrangement side of the exhaust mechanism 9 (left side in FIG. 1).

  Thus, according to this embodiment, the metal-containing gas is merged with the reactive gas that has become the active species by passing through the plasma space P, and the active species and the metal-containing gas react to contact each other to form a film. Therefore, the metal-containing gas is efficiently used for the film forming reaction, and the generation of electrode deposits and impurities can be prevented. Therefore, the deposition rate of the metal-containing thin film can be increased to an industrially usable rate, and the maintenance interval can be increased.

  In the plasma CVD apparatus shown in FIG. 1, the discharge space P and the gas introduction path 5 for the metal-containing gas are arranged in parallel and perpendicular to the surface to be processed of the substrate S. However, the present invention is not limited to this structure. The structure is such that the discharge space P and the gas introduction path 5 of the metal-containing gas are joined at an angle, or the joined gas is blown obliquely against the surface to be treated of the substrate S. May be.

<Embodiment 1>
FIG. 2 is a diagram schematically showing the configuration of the embodiment according to the first feature of the present invention.

  In this embodiment, in addition to the configuration of FIG. 1, the exhaust mechanism 10 is also arranged on the side of the opposing flat plate 40, and the lower portion of the opposing flat plate 40 extends to the vicinity of the substrate S to It is characterized in that the exhaust conductance by the exhaust mechanism 10 on the opposed flat plate 40 side is made smaller (for example, about 1/4) than the exhaust conductance by the exhaust mechanism 9 on the voltage application electrode 2 side. The other structure is the same as that of the form of FIG.

  According to the embodiment of FIG. 2, the exhaust conductance of the counter electrode 1 on the voltage application electrode 2 side and the exhaust conductance of the counter plate 40 side are controlled, so that almost the entire amount of the metal-containing gas introduced into the gas introduction path 5. Can flow in one direction (left side in FIG. 2). That is, the total flow rate of the introduction flow rates of the metal-containing gas and the reactive gas and the flow rate of the gas flow flowing substantially parallel to the substrate S can be made substantially the same amount. In addition, since no gas is trapped from the outside, it is particularly suitable for a film forming process in the case where mixing of impurities is disliked.

<Reference Embodiment 2>
FIG. 3 is a diagram schematically showing the configuration of another reference embodiment of the present invention.

  The plasma CVD apparatus shown in FIG. 3 includes two sets of counter electrodes 11 and 21 composed of voltage application electrodes 12 and 22 and ground electrodes 13 and 23, power supplies 61 and 62, reaction gas supply sources 71 and 72, and a metal-containing gas supply source. 80, exhaust mechanisms 91 and 92, and the like.

  The voltage application electrodes 12 and 22 and the ground electrodes 13 and 23 of each of the counter electrodes 11 and 21 are disposed to face each other with a predetermined distance therebetween. Each surface of each voltage application electrode 12, 22 and each ground electrode 13, 23 is covered with a solid dielectric (not shown).

  A reactive gas from a reactive gas supply source 71 is supplied between the voltage applying electrode 12 and the ground electrode 13 of the counter electrode 11 (plasma space P1). A reactive gas from a reactive gas supply source 72 is supplied between the voltage applying electrode 22 and the ground electrode 23 of the counter electrode 21 (plasma space P2).

  The counter electrode 11 and the counter electrode 21 have a structure in which the voltage application electrodes 12 and 22 and the ground electrodes 13 and 23 are symmetrically arranged (the ground electrodes 13 and 23 are inside). In addition, the ground electrode 13 of the counter electrode 11 and the ground electrode 23 of the counter electrode 21 are arranged in a state of facing each other with a predetermined interval, and a gas introduction path is provided between the two ground electrodes 13 and 23. 50 is formed. A metal-containing gas from a metal-containing gas supply source 80 is supplied to the gas introduction path 50.

  The exhaust mechanisms 91 and 92 are disposed on both sides of the two pairs of counter electrodes 11 and 21 at positions that are line-symmetric with respect to the central axis of the gas introduction path 50, and are on the counter electrode 11 side (left side in FIG. 3). ) And the exhaust conductance on the counter electrode 21 side (right side in FIG. 3) are the same. For each exhaust mechanism 91, 92, for example, a blower or the like is used.

In the plasma CVD apparatus having the above-described structure, the base material S is placed at a position facing the tips (blowers) of the two pairs of counter electrodes 11 and 21, and then forced exhaust is performed by the two exhaust mechanisms 91 and 92. Further, a metal-containing gas (for example, TMOS, TEOS, etc.) from the metal-containing gas supply source 80 is supplied to the gas introduction path 50, and between the voltage applying electrode 12 and the ground electrode 13 of the counter electrode 11, and between the counter electrode 21 and A reactive gas (such as O ₂ ) is supplied from the reactive gas supply sources 71 and 72 between the voltage application electrode 22 and the ground electrode 23, respectively.

  In this state, an electric field (pulse electric field) from the power source 61 or 62 is applied to each of the counter electrodes 11 and 21, respectively, and between the voltage applying electrode 12 and the ground electrode 13 and between the voltage applying electrode 22 and the ground electrode 23. Plasma spaces P1 and P2 are generated therebetween to excite each reactive gas. The reaction gas (excited state) that has passed through each of the plasma spaces P1 and P2 and the metal-containing gas that has passed through the gas introduction path 50 are blown out toward the substrate S from each outlet. Here, in this embodiment, since the apparatus configuration and the exhaust conductance are symmetrical, the gas flows for the respective gas flows of the respective reaction gases that pass through the plasma spaces P1 and P2 and are blown out from the gas outlets 11b and 21b. The flow of the shunt gas (a shunt gas of the metal-containing gas) blown out from the introduction path 50 is mixed to form a gas flow substantially parallel to the surface to be processed of the substrate S. Moreover, the mixed flow of the reaction gas and the gas metal-containing gas that has passed through the plasma space P1 (the gas flow to the left in FIG. 3), and the mixed flow of the reaction gas and the gas metal-containing gas that has passed through the plasma space P2 (see FIG. 3). Therefore, a high film formation rate can be stably obtained.

  In the structure shown in FIG. 3, forced exhaust is performed by the two exhaust mechanisms 91 and 92. However, if the gas flow rates of the reaction gases introduced into the counter electrodes 11 and 21 are the same, whether or not forced exhaust is present. Regardless of the gas flow rate of the metal-containing gas introduced into the gas introduction path 50, the mixed flow of the reaction gas and the gas metal-containing gas that has passed through the plasma space P1 (the gas flow to the left in FIG. 3), and the plasma space P2 It is possible to realize an equivalent state of the mixed gas (gas flow to the right in FIG. 3) of the reaction gas and the gas metal-containing gas that has passed through.

<Embodiment 2>
FIG. 4 is a diagram schematically showing the configuration of the embodiment according to the second feature of the present invention.

  This embodiment is characterized in that a gas rectifying plate 31 is provided at the lower end (gas blowing side) of the counter electrodes 11 and 21 in addition to the configuration of FIG.

If the gas rectifying plate 31 is provided in this way, the mixing uniformity and directionality of the combined gas of the reaction gas and the metal-containing gas can be improved, and further, the turbulence of the gas flow can be reduced. The film quality and the film formation speed can be further improved. When such a gas rectifying plate is provided, a ceramic porous plate is used as the gas rectifying plate 31, and N ₂ gas is blown out from the surface of the porous plate to prevent adhesion of the film to the gas rectifying plate 31. It is preferable.

  Here, in each above-mentioned form, plasma CVD processing is performed, conveying base material S in the horizontal direction (direction orthogonal to the plasma space of a counter electrode) of each figure.

  Examples of the present invention and non-claimed reference examples will be described below together with comparative examples.

<Reference Example 1>
In the plasma CVD apparatus of FIG. 1, the voltage application electrode 2 (made of SUS304: width 250 mm × length 50 mm × thickness 20 mm, solid dielectric: alumina) and the ground electrode 3 (made of SUS304: width 250 mm × length 50 mm × thickness 20 mm, A solid dielectric (alumina) was arranged with a 1 mm gap (plasma space P). Further, the gas introduction path 5 was formed by disposing an opposing flat plate 4 (manufactured by SUS304: width 250 mm × length 50 mm × thickness 20 mm) at an interval of 1 mm with respect to the ground electrode 3.
・ Processing conditions Reaction gas: O ₂ = 5 SLM
Source gas: TEOS = 0.2 g / min, N ₂ = 10 SLM
Base material: Si wafer (8 inch)
Base-electrode distance = 4 mm
Applied electric field: 5 kHz, 15 kV pulse electric field (pulse width 10 μs)
Substrate transport speed: 200 mm / min
Substrate temperature: 350 ° C
When film formation was performed on the surface of the substrate S with the above apparatus configuration and conditions, an SiO ₂ film having a film thickness of 1000 mm (film formation rate = 1000 kg / min) could be obtained.

<Example 1>
In the plasma CVD apparatus of FIG. 2, the distance between the lower end surface of the opposing flat plate 40 and the substrate S is 0.5 mm, and the exhaust conductance by the exhaust mechanism 9 on the voltage application electrode 2 side is on the opposing flat plate 40 side. The exhaust conductance by the exhaust mechanism 10 was reduced to ¼. Other configurations and film forming conditions are the same as in Reference Example 1, and when a film is formed on the surface of the substrate S, a SiO ₂ film having a film thickness of 1000 mm (film forming speed = 1000 mm / min) can be obtained. did it.

<Reference Example 2>
In the plasma CVD apparatus of FIG. 3, each voltage application electrode 12 and 22 (SUS304: width 250 mm × length 50 mm × thickness 20 mm, solid dielectric: alumina) and each ground electrode 13 and 23 (SUS304: width 250 mm × length) 50 mm × 20 mm in thickness, solid dielectric: alumina) were arranged with an interval of 1 mm (plasma spaces P1, P2). In addition, the gas introduction path 50 was formed by arranging the two ground electrodes 13 and 23 at an interval of 1 mm.
Processing conditions Reaction gas: O ₂ = 10 SLM (plasma space P1), O ₂ = 10 SLM (plasma space P2)
Source gas: TEOS = 0.2 g / min, N ₂ = 10 SLM
Base material: Si wafer (8 inch)
Base-electrode distance = 4 mm
Applied electric field: 5 kHz, 15 kV pulse electric field (pulse width 10 μs)
Substrate transport speed: 200 mm / min
Substrate temperature: 350 ° C
When a film was formed on the surface of the substrate S with the above apparatus configuration and conditions, a SiO ₂ film could be obtained at a film formation rate of about 700 Å / min. Further, the film was formed by changing the discharge frequency of the applied electric field (0 to 6 kHz). The film formation results (relationship between discharge frequency and film formation rate) are shown in FIG.

<Comparative Example 1>
As shown in FIG. 5, a plasma CVD apparatus without an exhaust mechanism was used. The other apparatus configuration and film formation conditions were the same as in Example 1, and when a film was formed on the surface of the substrate S, a SiO ₂ film could be obtained at a film formation rate of about 500 Å / min. Further, when the film was formed by changing the discharge frequency of the applied electric field (0 to 5 kHz), a film formation result (relationship between the discharge frequency and the film formation rate) as shown in FIG. 7 was obtained.

<Comparison between Reference Example 2 and Comparative Example 1>
In Comparative Example 1 (conventional plasma CVD apparatus), the film forming speed was limited to about 500 Å / min, but in Reference Example 2 (plasma CVD apparatus in FIG. 3), film formation was up to about 700 Å / min. The speed is increasing. Further, in Comparative Example 1, when the discharge frequency is increased, a phenomenon in which the gas-phase reaction proceeds excessively and the film formation rate decreases is observed, but in Reference Example 2, such a phenomenon is not found. In Reference Example 2, it was also found that by increasing the concentration of the source gas (metal-containing gas) and optimizing the discharge conditions, a high film formation rate of 5000 to 10000 Å / min can be obtained.

It is a figure which shows typically the structure of reference embodiment of this invention. It is a figure which shows typically the structure of embodiment which concerns on the 1st characteristic of this invention. It is a figure which shows typically the structure of another reference embodiment of this invention. It is a figure which shows typically the structure of embodiment which concerns on the 2nd characteristic of this invention. It is a figure which shows typically the apparatus structure used for the comparative example of this invention. It is a figure which shows the film-forming result of the reference example 2 of this invention, and is a graph which shows the relationship between the film-forming speed | rate and discharge frequency. It is a figure which shows the film-forming result of the comparative example of this invention, and is a graph which shows the relationship between the film-forming speed | rate and discharge frequency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Counter electrode 1a Gas inlet 1b Gas outlet 2 Voltage application electrode 3 Ground electrode P Plasma space 4,40 Opposite flat plate 5 Gas introduction path 6 Power supply 7 Reactive gas supply source 8 Metal-containing gas supply source 9, 10 Exhaust mechanism 11, 21 Counter electrode 11b, 21b Gas outlet 12, 22 Voltage application electrode 13, 23 Ground electrode P1, P2 Plasma space 31 Gas rectifying plate 50 Gas introduction path 61, 62 Power source 71, 72 Reactive gas supply source 80 Metal-containing gas supply source 91, 92 Exhaust mechanism

Claims (2)

  A plasma CVD apparatus using a metal-containing gas and a reactive gas that reacts with the metal-containing gas, an electrode that generates a plasma space at normal pressure, a reactive gas supply source that supplies the reactive gas to the plasma space, and the plasma A metal-containing gas supply source that supplies a metal-containing gas in the vicinity of a reaction gas outlet that has passed through the space, and an exhaust mechanism that performs exhaust control of the direction in which the combined gas of the reaction gas and the metal-containing gas passes through the plasma space The exhaust mechanism is arranged on both sides of the merge point, and the conductance of the flow channel far from the plasma space among the merge gas channels from the merge point to the exhaust mechanism is configured to be small. A plasma CVD apparatus characterized by that.   A plasma CVD apparatus using a metal-containing gas and a reactive gas that reacts with the metal-containing gas, two sets of electrodes that generate a plasma space at normal pressure, and a reactive gas supply source that supplies the reactive gas to each plasma space A metal-containing gas supply source that supplies a metal-containing gas between two outlets from which the reaction gas that has passed through the two plasma spaces is blown out, and the blown-out reaction gas and the metal-containing gas A gas rectifying plate that forms a flow path of the combined gas along the surface to be processed, the gas rectifying plate covering all surfaces of the two sets of electrodes facing the processing surface, and the two sets of electrodes Both ends of the gas rectifying plate protrude outward from the electrodes disposed on both outer sides, and both ends of the gas flow rectifying plate that are separated from the two reaction gas outlets by the flow path of the combined gas. Even more outside Plasma CVD apparatus characterized by exhaust mechanism is arranged to.

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