Plasma CVD apparatus

Abstract

To provide an apparatus capable of stably performing plasma CVD.SOLUTION: A plasma CVD apparatus includes a plasma head (2) for supplying plasma (p) generated from career gas (g0) and a raw material gas head (3) for supplying raw material gas (gm) for reacting with plasma to perform chemical vapor phase deposition. The plasma head includes: a first electrode (221), middle insulator (212) and second electrode (222) laminated from the upstream side supplying the career gas; a communication hole (20) capable of penetrating the first electrode, middle insulator and second electrode to pass the career gas; and a slender plasma discharge hole (23) on the downstream opening side of the communication hole. The raw material gas head includes a slender raw material gas discharge hole (33) arranged in approximately parallel in the longitudinal direction in the vicinity of the plasma discharge hole.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a plasma CVD apparatus and the like that performs chemical vapor deposition (CVD) of a source gas using plasma. [Background technology]

[0002] Plasma, in which gas molecules (atoms) are ionized mainly into cations and electrons (collectively referred to as "charged particles"), is used in a variety of fields for various treatments and processes. For example, low-temperature plasma obtained by glow discharge has excellent controllability and is used for thin film formation by chemical vapor deposition (CVD). Such a plasma CVD apparatus is described, for example, in Patent Document 1 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-82491 [Patent Document 2] Patent Publication No. 2021-82491 [Patent Document 3] Patent Publication No. 2022-127786 Summary of the Invention [Problem to be solved by the invention]

[0004] The film formation apparatus described in Patent Document 1 performs CVD under high vacuum conditions, making the equipment large, complex, and expensive. Simplifying the apparatus and easing the processing environment (for example, processing under (sub)atmospheric) pressure would dramatically expand the range of applications (uses) of plasma CVD, enabling a variety of processes to be performed more efficiently.

[0005] Apparatuses that enable plasma processing even in an atmosphere near atmospheric pressure are proposed in Patent Documents 2 and 3. However, Patent Documents 2 and 3 only propose a supply device for the plasma itself and do not disclose a specific configuration for the CVD apparatus.

[0006] The present invention has been made in view of the above circumstances, and has as its object to provide a new plasma CVD apparatus and the like. [Means for solving the problem]

[0007] As a result of intensive research into solving this problem, the inventor came up with the idea of ​​indirectly converting source gas into plasma, and realized an apparatus that can stably perform plasma CVD. By expanding on this result, the present invention, which will be described below, was completed.

[0008] Plasma CVD equipment (1) The present invention is a plasma CVD apparatus comprising a plasma head that supplies plasma generated from a carrier gas, and a raw material gas head that supplies a raw material gas that reacts with the plasma to cause chemical vapor deposition, the plasma head having a first electrode, an intermediate insulator, and a second electrode stacked from the upstream side where the carrier gas is supplied, a communication hole that penetrates the first electrode, the intermediate insulator, and the second electrode to allow the carrier gas to flow, and an elongated plasma discharge hole on the downstream opening side of the communication hole, and the raw material gas head having elongated raw material gas discharge holes arranged approximately parallel to the longitudinal direction near the plasma discharge hole.

[0009] (2) In the plasma CVD apparatus (also simply referred to as "apparatus") of the present invention, first, a discharge (glow discharge or arc discharge) occurs between the inner wall surfaces of the first electrode and the second electrode exposed in the communicating hole of the plasma head, and plasma (electrons, radicals, ions, etc.) is generated (excited) from the flowing carrier gas (at least a part of it). This plasma flows with the flow of the carrier gas and flows out (including ejection, etc.) from the plasma discharge hole.

[0010] Next, the raw material gas discharge holes of the raw material gas head are disposed near (downstream of) the plasma discharge holes, and the raw material gas flowing out from the raw material gas discharge holes comes into contact with (converges with) the plasma flowing out from the plasma discharge holes and reacts indirectly (becomes plasma). The reactant of the raw material gas thus obtained deposits on the surface of the workpiece to form a film or modify the surface, for example.

[0011] In the apparatus of the present invention, a source gas reaction section is set downstream of the plasma generation section, separating the two. This prevents or avoids the occurrence of source gas decomposition products covering the surface of the electrode that generates the plasma, causing fluctuations in discharge characteristics, or the formation of droplets on the surface being treated due to the peeling or falling off of deposits of the decomposition products (carbides, etc.). In this way, the apparatus of the present invention prevents deposits from forming on the electrodes, etc., and allows plasma CVD (processing) to be performed stably for long periods of time.

[0012] Incidentally, when the source gas is indirectly converted into plasma, the efficiency of the energy imparted to the source gas may be lower than when the source gas is directly converted into plasma between electrodes. However, in the device of the present invention, both the plasma outlet and the source gas outlet are elongated and arranged close to each other. This ensures that the source gas is imparted with sufficient energy necessary for activation (reaction), even when indirectly converted into plasma. In this case, the source gas undergoes linear chemical vapor deposition, and by moving both heads relative to the workpiece, a wide area of ​​the workpiece can be uniformly and efficiently processed. Furthermore, indirect conversion of the source gas into plasma avoids excessive energy imparted to the source gas, which would otherwise occur when direct conversion into plasma occurs, and the resulting failure to obtain the desired product.

[0013] <Plasma CVD processing / processed material> The present invention can also be understood as a method for performing plasma CVD processing using the above-described apparatus (including a method for producing the resultant product). The present invention can also be understood as a resultant product (processed product or product (polymer, compound, film, etc.)) obtained by the method.

[0014] The raw material gas to be merged into the plasma may be of any type, component, amount, with or without mixing, etc. For example, the raw material gas may be a single type of monomer gas, and the (plasma) product may be its polymer. Also, the raw material gas may be a mixed gas containing two or more types of gases, and the product may be a synthetic substance or a compound, etc.

[0015] 《Others》 (1) "Chemical vapor deposition" or "CVD" as referred to in this specification means that the raw material gas reacts with the plasma to change its properties and state. That is, CVD as referred to in this specification is not limited to the deposition of products on the surface of the object to be processed. For example, it may also be the modification of the surface of the object to be processed by the plasma - converted raw material gas, the formation of new synthetic substances on the surface of the object to be processed, etc.

[0016] (2) "Up / down (upstream / downstream)" as referred to in this specification is defined by the direction of the flow of the carrier gas or plasma, and is not related to the vertical direction unless otherwise specified. For this reason, as appropriate, the surface, end, etc. on the upstream side are referred to as the upper surface, upper end, etc., and the surface, end, etc. on the downstream side are referred to as the lower surface, lower end, etc. Also, inside / outside is based on the communication hole or discharge hole. For example, the surface constituting the communication hole is referred to as the inner wall surface, inner peripheral surface, inner surface, etc.

[0017] (3) "Near atmospheric pressure" as referred to in this specification is, for example, an atmospheric pressure (P) that satisfies 0.01P0 ≦ P ≦ 1.1P0 with respect to the atmospheric pressure (P0), and the gas species is not limited. "Sub - atmospheric pressure" is an atmospheric pressure less than the atmospheric pressure, for example, 0.01P0 ≦ P < P0. Based on the standard atmospheric pressure (P0 = 1.01325×10 5 Pa ≒ 1×10 5 Pa), for example, 1×10 3 Pa ≦ P ≦ 1×10 5 Pa may also be considered as near atmospheric pressure.

[0018] (4) Unless otherwise specified, "x to y" in this specification includes a lower limit value x and an upper limit value y. A new range such as "a to b" can be established by setting any numerical value included in the various numerical values ​​or numerical ranges described in this specification as a new lower limit or upper limit value. Unless otherwise specified, "x to y mm" in this specification means x mm to y mm. The same applies to other unit systems. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view illustrating an example of an outline of a plasma CVD apparatus. [Figure 2] FIG. [Figure 3A] FIG. 2 is an enlarged cross-sectional view of the main part. [Figure 3B] FIG. [Figure 4] The analytical model and analytical conditions for simulating the arrangement of the plasma head and the source gas head are shown below. [Figure 5] FIG. 10 is a diagram showing the electron number density distribution obtained by the simulation. DETAILED DESCRIPTION OF THE INVENTION

[0020] One or more components arbitrarily selected from this specification may be added to the above-described components of the present invention. The contents described in this specification apply not only to the apparatus but also to the processing method and its resultant products (processed products, products, etc.) as appropriate. Method-related components may also be product-related components. Which embodiment is best depends on the target, required performance, etc.

[0021] Plasma Head The plasma head has at least a first electrode, an intermediate insulator, and a second electrode (collectively referred to as the "generation section") stacked in order from the upstream side, a communication hole that passes through them to allow the carrier gas to flow, and a plasma discharge hole that discharges the generated (excited) plasma.

[0022] (1) Generation section The electrodes are made of metal materials such as stainless steel, iron, copper, titanium, tungsten, aluminum, etc. The intermediate insulators are made of ceramics, quartz, glass, polytetrafluoroethylene, polyimide, etc. Ceramics include alumina (Al2O3), aluminum nitride (AlN), and boron nitride (BN), which have excellent heat resistance.

[0023] The thickness of the electrodes is, for example, 0.5 to 30 mm, or even 1 to 15 mm. The thickness of the intermediate insulator (the distance between the first electrode and the second electrode) is, for example, 0.2 to 5 mm, or even 0.5 to 3 mm.

[0024] The inner wall surface of the intermediate insulator may have an annular recess (concave) that is offset more radially outward than the inner wall surfaces of the electrodes. This prevents dielectric breakdown (short circuit) along the inner wall surface (creepage) of the intermediate insulator. Furthermore, the inner wall surface of the intermediate insulator is located away from the inner periphery (corners of the longitudinal cross section) of each electrode, where discharge tends to concentrate, thereby preventing unstable arc discharge.

[0025] The displacement (Δr) of the inner wall surface of the intermediate insulator is, for example, Δr≧t, Δr≧2t, or even Δr≧3t, where t is the thickness of the intermediate insulator. When the inner wall surface of the intermediate insulator is symmetrically displaced (concave), D=d+2Δr or Δr=(Dd) / 2, where d is the distance between the opposing inner wall surfaces of the first electrode or second electrode, and D is the distance between the opposing inner wall surfaces of the intermediate insulator.

[0026] If each electrode is covered with an insulator except for the inside of the communication hole, unnecessary discharge can be avoided. The area near the bottom surface of the second electrode, which is close to the source gas head and the workpiece, should be covered with an insulator (material) or should have a circuit formed so that the potential difference with the surrounding area is small (or even so that it is at the same potential).

[0027] (2) Communication holes and plasma outlet holes The cross section of the communicating hole may be the same as or different from the plasma ejection hole. For example, the communicating hole may be a single hole, multiple holes, slit-shaped (long hole-shaped), etc. Of course, the lower end opening of the communicating hole may be used as the plasma ejection hole.

[0028] The plasma discharge hole has a length-to-width ratio (ratio (b / a) of maximum length (b) in the longitudinal direction (horizontal direction) to maximum length (a) in the short side direction (vertical direction)) of, for example, 10 to 10,000, 50 to 5,000, or 100 to 1,000. The specific dimensions and ratios can be adjusted depending on the application and specifications of the device. For example, the width (a) may be 0.1 to 20 mm or 0.5 to 10 mm, and the length (b) may be 20 to 2,000 mm or 40 to 1,000 mm.

[0029] The specific shape (slit shape) of the plasma discharge hole may be, for example, rectangular (linear), oblong, long hole, etc. The plasma discharge holes are not limited to a single row (single line) but may be multiple rows. In the case of multiple rows, the rows should preferably be arranged approximately parallel to each other. The plasma discharge holes do not necessarily have to be linear, and may be curved two-dimensionally or three-dimensionally depending on the workpiece and application. The above discussion of the shape of the plasma discharge holes also applies to the source gas discharge holes of the source gas head.

[0030] (3) Cooling mechanism The plasma head should be equipped with a cooling mechanism to prevent overheating. The entire plasma head may be cooled, or at least the area around the plasma nozzle may be cooled. This prevents excessive reaction of the source gas and damage to the plasma head.

[0031] The cooling mechanism can take various forms, but for example, a coolant flow path can be provided in the plasma head. The coolant can be, for example, a carrier gas (especially an inert gas) that is the plasma source. Even if such gas leaks, it has little adverse effect on the plasma CVD.

[0032] <<Raw material gas head>> The source gas head supplies the source gas for chemical vapor deposition to the vicinity (downstream side) of the plasma discharge holes. The source gas discharge holes also have an elongated shape corresponding to the plasma discharge holes, and the two are arranged approximately parallel to each other in the longitudinal direction. Note that the specific dimensions and aspect ratios of the source gas discharge holes and the plasma discharge holes may differ.

[0033] The opening (hole) direction of the source gas ejection holes (source gas outflow direction) can be adjusted as appropriate, but for example, it is preferable that the source gas be directed downstream of the plasma ejection holes. In this case, the source gas smoothly merges with the plasma (carrier gas) and easily undergoes chemical vapor deposition on the processing surface.

[0034] The source gas ejection holes are preferably located closer to the plasma ejection holes than to the surface to be processed (the surface of the object to be processed), which reduces the amount of unreacted source gas and allows for sufficient chemical vapor deposition.

[0035] The distance (vertical direction) from the surface to be treated to the plasma discharge hole is adjusted as appropriate, but is, for example, 1 to 20 mm or 3 to 10 mm. The vertical distance from the plasma discharge hole to the upper opening edge of the raw material gas discharge hole is, for example, 0 to 20 mm or 1 to 8 mm. The front-to-rear distance from the opening end of the plasma discharge hole to the opening end of the raw material gas discharge hole is, for example, 0 to 5 mm or 0.5 to 1 mm. The distance from the plasma discharge hole to the raw material gas discharge hole is adjusted depending on the plasma conditions, and a longer distance is required under high-power conditions. By optimizing this distance, excessive energy is avoided from being applied to the raw material gas, and the generation or inclusion of unwanted substances (for example, carbonized matter in a polymer film) is avoided.

[0036] 《Transportation / Stage》 It is preferable to have a moving means for moving the plasma head and the source gas head relative to the workpiece. A heating means (heater), a cooling means (cooler), or a temperature adjusting means (including a control means) may be provided on the stage on which the workpiece is placed.

[0037] "power supply" The power source that generates the electric field between the first electrode and the second electrode may be a DC power source, an AC power source, or a pulse power source. The frequency of the AC power source or pulse power source is, for example, 1 kHz to 100 kHz or 2 kHz to 20 kHz.

[0038] The applied voltage (peak-to-peak value / maximum and minimum voltage difference) is, for example, 200 to 3000 V, or even 400 to 1500 V. When the second electrode is grounded, the potential required for plasma generation is applied to the first electrode. The stage on which the workpiece is placed and the second electrode may be at the same potential, or a bias potential may be applied. When a metal chamber is used, it is recommended that the chamber be grounded.

[0039] "atmosphere" The atmosphere in which plasma CVD is performed may be a vacuum atmosphere or a (quasi) atmospheric pressure atmosphere (for example, 1000 Pa to 50000 Pa). When processing is performed in a processing furnace (chamber), gas leakage and the like can be avoided.

[0040] "gas" The carrier gas that serves as the plasma source is, for example, an inert gas (a rare gas (Ar, Ne, He, etc.), N2, etc.). In addition to the inert gas, the carrier gas may contain substances that do not contaminate the inside of the communicating holes and substances that promote plasma CVD, such as hydrogen and nitrogen.

[0041] Any type of raw material gas can be used. For example, when a monomer gas is subjected to plasma CVD, a polymerized polymer (such as a polymerized film) is obtained. Plasma polymerization can promote three-dimensional cross-linking between monomers in a dry environment. [Example]

[0042] The present invention will be explained in more detail with reference to a specific example of a plasma CVD apparatus.

[0043] 《Device configuration》 An overview of a plasma CVD apparatus S (simply referred to as "apparatus S") according to one embodiment of the present invention is shown in FIG. 1. Its cross-sectional view is shown in FIG. 2, an enlarged cross-sectional view of a main portion is shown in FIG. 3A, and a cross-sectional view in another direction is shown in FIG. 3B. For ease of explanation, the directions of the arrows shown in FIG. 1 will be referred to as the front-rear direction, left-right direction, or up-down direction as appropriate. However, the up-down direction follows the flow of carrier gas or plasma within the apparatus S, with the upstream side being the top and the downstream side being the bottom.

[0044] The apparatus S includes an introduction part 1, a plasma head 2, a raw material gas head 3, a stage 4 on which a workpiece w (object to be processed) is placed, a power supply 6, a chamber 7, and a vacuum pump 8. The introduction part 1, the plasma head 2, the raw material gas head 3, and the stage 4 are housed (stored) in the chamber 7.

[0045] (1) The introduction section 1 has an inlet 11 for introducing a carrier gas g0 that serves as a plasma source, a roughly rectangular parallelepiped cover 12, and pipes 131 and 132 for a refrigerant gas g1 that penetrate the cover 12 in the vertical direction (together referred to as "pipes 13").

[0046] Carrier gas g0 introduced into cover 12 through inlet 11 is introduced into communication hole 20. Coolant gas g1 flows in through pipe 131 and flows out through pipe 132 to cool the area around plasma head 2. Carrier gas g0 and coolant gas g1 are the same inert gas (N2 or Ar). Coolant gas g1 flowing out through pipe 132 is exhausted by vacuum pump 8. As a result, the entire interior of chamber 7 is filled with an inert gas atmosphere at a predetermined pressure (approximately subatmospheric pressure).

[0047] The cover 12 is made of metal (for example, stainless steel) and is electrically connected to an electrode plate 221, which will be described later.

[0048] (2) The plasma head 2 includes an electrode plate 221 (first electrode), an insulating plate 212 (intermediate insulator), and an electrode plate 222 (second electrode), which are stacked in this order from above, and an insulating tube 211 (external insulator) that surrounds the outer peripheries of these. The inner circumferential surface of the insulating tube 211 is in close contact with the outer circumferential (end) surfaces of the electrode plate 221, the insulating plate 212, the electrode plate 222, and the introduction portion 1 (cover 12). The insulating plate 212, the electrode plate 221, and the electrode plate 222 are rectangular, and the insulating tube 211 is square cylindrical.

[0049] The plasma head 2 further has a slit-shaped through-hole 20 that penetrates approximately the center in the vertical direction and extends in the horizontal direction. The through-hole 20 is formed by a hole 2210 in the electrode plate 221, a hole 2120 in the insulating plate 212, and a hole 2220 in the electrode plate 222.

[0050] When a high voltage is applied between electrode plate 221 and electrode plate 222, a discharge (mainly a glow discharge) occurs between inner wall surface 2210a of hole 2210 and inner wall surface 2220a of hole 2220, generating plasma p within communication hole 20. Plasma p is pushed out by carrier gas g0 flowing from upstream to downstream within communication hole 20, and is ejected from elongated plasma discharge hole 23 which is the opening on the lower end side of communication hole 20.

[0051] The plasma discharge hole 23 may be provided separately from the lower end opening of the communication hole 20 (hole 2220). For example, the communication hole 20 or its lower end opening is not limited to a single-row slit shape, but may be a double-row shape or a multiplicity of arranged (circular) holes. The plasmas p flowing out from the lower end openings of such communication holes 20 may be unified and discharged (ejected) in a substantially linear fashion from the elongated slit-shaped plasma discharge hole 23.

[0052] Inner wall surface 2210a of hole 2210 and inner wall surface 2220a of hole 2220 are flush with each other all around in the vertical direction. Inner wall surface 2120a of hole 2120 is offset outward (in the front-to-back direction) relative to these inner wall surfaces. In other words, inner wall surface 2120a forms a recess 20a that is recessed relative to the other inner wall surfaces that make up communicating hole 20.

[0053] 2, if the distance between opposing inner wall surfaces 2120a is D, the distance between opposing inner wall surfaces is d, and the amount of deviation of inner wall surface 2120a relative to the other inner wall surfaces is Δr, then D=d+2Δr. Here, the deviation of inner wall surface 2120a is symmetrical front to back. If the thickness of insulating plate 212 is t, then Δr≧t (or D≧d+2t) should be satisfied.

[0054] (3) The source gas head 3 is arranged adjacent to the plasma head 2 and supplies the source gas g m The nozzle 31 has a tip opening that is an elongated slit-shaped source gas discharge hole 33. m Unlike the carrier gas g0 (refrigerant gas g1), is a gas that reacts with the plasma p to cause chemical vapor deposition.

[0055] The raw material gas discharge hole 33 is disposed near the downstream side of the plasma discharge hole 23. The plasma discharge hole 23 and the raw material gas discharge hole 33 extend parallel to each other in the longitudinal direction (the left-right direction in FIG. 1) and have approximately the same shape.

[0056] The plasma discharge hole 23 and the raw material gas discharge hole 33 are aligned in the outflow direction (Lp) of the plasma p (carrier gas g0) and the raw material gas g m Specifically, the angle between the outflow direction (Lp) and the outflow direction (Lm) is set to about 90° to 45° or 80° to 60°, and the raw material gas discharge holes 33 are directed toward the workpiece w.

[0057] The raw material gas discharge holes 33 are arranged close to the plasma discharge holes 23, slightly spaced from the surface of the workpiece w. Specific dimensions (distance, interval, etc.) are adjusted as appropriate, but examples are as follows: The opening dimensions of the plasma discharge holes 23 are, for example, 1 to 5 mm (width / length) x 25 to 200 mm (length / width). The opening dimensions of the raw material gas discharge holes 33 are, for example, 1 to 5 mm (width / length) x 25 to 200 mm (length / width).

[0058] The longitudinal (left-right) positional deviation (distance between the opening ends) of the raw material gas discharge hole 33 and the plasma discharge hole 23 is, for example, about 0 to 10%, or even 1 to 5% of the longitudinal distance (maximum opening length (slit length) of the raw material gas discharge hole 33 or the plasma discharge hole 23). The vertical distance (vertical gap) from the opening end face of the plasma discharge hole 23 to the surface of the workpiece w is, for example, 1 to 20 mm or 2 to 10 mm. The horizontal distance (front-rear distance) from the opening end face of the raw material gas discharge hole 33 to the opening end face of the plasma discharge hole 23 is, for example, 0 to 5 mm or 1 to 4 mm.

[0059] (4) The stage 4 includes a base 41, a heater 42 (heating means) built into the base 41, a drive mechanism (not shown) that moves the base 41 in the planar directions (X-axis direction and Y-axis direction), and a control device (not shown) that controls the heater 42 and drive mechanism. The heater 42 and control device manage the temperature of the workpiece w placed on the base 41 (temperature adjustment means). The drive mechanism and control device manage the position of the workpiece w placed on the base 41, adjust the processing speed, etc. (movement means).

[0060] The power supply 6 is, for example, a high-frequency power supply device that generates a pulsed voltage at a desired frequency. The power supply 6 applies a voltage required to generate plasma between the electrode plate 221 and the electrode plate 222. The electrode plate 222 and the stage 4 (base 41) are both grounded, and electricity is applied to the electrode plate 221 via the cover 12.

[0061] The chamber 7 is evacuated by a vacuum pump 8 to create a sub-atmospheric pressure atmosphere.

[0062] Plasma CVD (1) Using the actually manufactured device S, a monomer gas (raw material gas g) is injected onto the workpiece w (substrate). m ) A polymer film was formed. The specific conditions are as follows. Regarding the plasma head 2 that generates the plasma p, the descriptions in Japanese Patent Application Laid-Open No. 2021-82491 and Japanese Patent Application Laid-Open No. 2022-127786 were used as reference. Therefore, the contents described in these patent documents are incorporated into this specification as appropriate.

[0063] (2) Rolled stainless steel (SUS304) plates were used for the electrode plates 221 and 222, and sintered alumina (Al2O3) was used for the insulating tube 211 and insulating plate 212. The thickness of the electrode plate 221 was 2 mm, the thickness of the electrode plate 222 was 1 mm, and the thickness (t) of the insulating plate 212 was 1 mm. The thickness of the insulating tube 211 was 5 mm and the height (L) was 33 mm.

[0064] The opening shapes of the plasma discharge hole 23 and the raw material gas discharge hole 33 were 1 mm × 100 mm. The distance (d) between the opposing inner wall surfaces of the holes 2210 and 2220 in the front-to-rear direction was 1 mm. The deviation (Δr) of the inner wall surface 2120a of the hole 2120 was 1 mm. The distance (minimum distance) between the opening ends of the plasma discharge hole 23 and the raw material gas discharge hole 33 in the horizontal direction (front-to-rear direction) was 1 mm, and the distance (minimum distance) between the opening ends thereof in the vertical direction (up-down direction) was 2 mm.

[0065] The chamber 7 was evacuated to 1.3 kPa (absolute pressure) by a vacuum pump 8. N2 (carrier gas g) was supplied to the communication hole 20 of the plasma head 2 at a rate of 0.3 L / min. C2H2 (acetylene: source gas g) was supplied to the nozzle 31 of the source gas head 3. m A pulse voltage (900 V (peak to peak value) × frequency 2 kHz, square wave) was applied between the electrode plate 221 and the electrode plate 222.

[0066] A purple glow discharge and the generation (ejection) of linear plasma p were observed near the plasma discharge port 23. A reaction product (light brown) with the plasma p was observed near the raw material gas discharge port 33. A thin film of the product (polymer) was formed on the workpiece w (SPCC flat plate). The vertical distance from the surface of the workpiece w to the plasma discharge port 23 was 8 mm. The raw material gas discharge port 33 and the plasma discharge port 23 formed an angle of 90° between their flow directions.

[0067] "analysis" (1) The appropriate arrangement of the plasma outlet 23 and the source gas outlet 33 was investigated by simulation. The analytical model and analytical conditions (Table 1) are summarized in Figure 4. The carrier gas g0 was N2, and its introduction rate was 0.3 L / min. The atmosphere in the chamber was 300 K (27 °C) × 1.3 × 10 3 It was Pa.

[0068] (2) Simulation results (electron density distribution) for voltages applied between the electrodes of 600 V, 900 V, and 1200 V are summarized in Figure 5. As can be seen from Figure 5, the electron number density near the plasma discharge hole 23 was 0.35 × 10 within 8 mm above the plasma discharge hole 23 under any of the conditions from 600 V to 1200 V. 16 pieces / m 3 That's all.

[0069] When the source gas discharge holes 33 are arranged within a range of 8 mm in the vertical direction, the source gas g m This allows the supply of raw gas g m can be reacted sufficiently with the plasma p to obtain, for example, a desired polymerized film.

[0070] Particularly under high voltage (1200V) conditions, the electron number density becomes considerably high near the plasma outlet 23. If the raw material gas is supplied to plasma p with such a high electron number density, for example, carbonization of the polymer may occur. Therefore, for example, when the electron number density is 0.35 to 1.0 × 10 16 pieces / m 3 The source gas outlet holes 33 are preferably arranged so that the source gas can be supplied to the plasma region where the source gas is to be injected.

[0071] From the above, it was confirmed that the apparatus of the present invention can perform chemical vapor deposition of a source gas stably over a long period of time, and can efficiently perform film formation, surface treatment, and the like. [Explanation of symbols]

[0072] S Plasma CVD equipment w Workpiece (processing object) 2 Plasma Head 20 Communication hole 23 Plasma outlet 3 Raw gas head 33 Raw material gas outlet hole

Claims

1. a plasma head for supplying plasma generated from a carrier gas, and a source gas head for supplying a source gas for chemical vapor deposition by reacting with the plasma; The plasma head comprises: a first electrode, an intermediate insulator, and a second electrode stacked in this order from the upstream side of the carrier gas supply; a communication hole that passes through the first electrode, the intermediate insulator, and the second electrode to allow the carrier gas to flow; a thin and long plasma ejection hole located on the downstream opening side of the communication hole, The source gas head includes: a plasma CVD apparatus having elongated source gas ejection holes arranged approximately parallel to each other in the longitudinal direction near the plasma ejection holes;

2. 2. The plasma CVD apparatus according to claim 1, wherein the plasma head includes a cooling mechanism for suppressing overheating at least in the vicinity of the plasma ejection nozzle.

3. the cooling mechanism includes a refrigerant flow path, 3. The plasma CVD apparatus according to claim 2, wherein the refrigerant is the same as the carrier gas.

4. 2. The plasma CVD apparatus according to claim 1, wherein the plasma discharge holes and the source gas discharge holes have a length to width ratio of 10 or more.

5. 2. The plasma CVD apparatus according to claim 1, wherein the raw material gas discharge holes cause the raw material gas to flow downstream of the plasma flowing out of the plasma discharge holes, and the raw material gas does not flow between the first electrode and the second electrode.

6. 2. The plasma CVD apparatus according to claim 1, wherein the source gas ejection holes are located closer to the plasma ejection holes than the surface to be processed.

7. 2. The plasma CVD apparatus according to claim 1, wherein the chemical vapor deposition is performed under a subatmospheric pressure atmosphere.

8. the raw material gas is a monomer gas, 10. The plasma CVD apparatus according to claim 1, wherein the monomer gas is polymerized by the chemical vapor deposition.

9. 2. The plasma CVD apparatus according to claim 1, wherein the carrier gas comprises one or more inert gases.

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