JPH0657435A - Plasma cvd device - Google Patents

Abstract

PURPOSE:To form a reaction film while maintaining a substrate at a low temp. by confining the plasma in the form of a beam by a magnetic field and disposing the substrate in the outer peripheral part in the diametral direction of the beam-shaped plasma and outside a discharge region. CONSTITUTION:The plasma is introduced from a plasma source 1 having a main coil 14 for assisting an arc discharge into a vacuum chamber 2 which is subjected to a pressure reduction and grounding. The gaseous material supplied from a nozzle 13 is activated by the plasma and the reaction film is formed on the substrate 11 maintained at a prescribed temp. A plasma reflection electrode 17 is disposed to face the plasma source 1 and an auxiliary coil 20 generating a magnetic field is disposed near the electrode. As a result, the plasma is confined to a beam shape between the plasma source 1 and the reflection electrode 17. Further, the substrate 11 is disposed in the outer peripheral part in the diametral direction of this beam-shaped plasma and outside the discharge region. As a result, the bombardment of the substrate 11 by the high- energy electrons existing in the plasma is suppressed and the temp. rise of the substrate 11 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for forming a reaction film on a substrate which is an object to be processed by a plasma CVD method, and particularly to a reaction film while keeping the substrate at a low temperature of, for example, 200 ° C. or lower. The present invention relates to a plasma CVD apparatus for forming a film.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a structure of a main part of a conventional plasma CVD apparatus. In the figure, 31 is a plasma source,
32 is a vacuum chamber connected to the plasma source. The plasma source 31 is provided with a hot cathode filament (hereinafter referred to as a hot cathode) 33, an anode 34, and a gas nozzle 35. The hot cathode 33 is made of a high melting point material such as Ta, Mo and W, and is red-heated by a hot cathode heating power source 36 having a power capacity of about 20V and 50A, for example. The anode 34 is supplied with an anode power source 37, and the potential of the hot cathode 33 is set to 0 V as a reference.
A voltage of ˜ + 100V, usually + 50V is applied. A bias voltage of 0V to -100V, usually about -45V is applied to the hot cathode 33 by a bias power source 38 with reference to the ground potential.

The vacuum chamber 32 is connected to a vacuum pump (not shown) through an exhaust pipe 39. The vacuum chamber 32 is grounded. In the vacuum chamber 32, a substrate support base 40 is provided in the discharge region so as to face the plasma source 31, and a substrate 41, which is an object to be processed, is placed on the substrate support base. The substrate 41 is biased by the substrate power source 42 via the substrate support 40 to 0 to -1000V, usually about -100V. 43 is a heater, which is the substrate 40
Is heated to a predetermined temperature.

Conventional in the plasma CVD apparatus, Ar from the gas nozzle 35, N _2, H _2, a discharge gas such as H _e and a predetermined source gas, for example, silane gas (SiH in Figure 2
₄ ) to introduce. Further, the vacuum pump is operated to adjust the pressure in the vacuum chamber to the level of 10 ⁻³ to 10 ⁻⁵ Torr, for example, 7 × 10 5.
Keep at ^-4 Torr. Further, the magnetic field generating coil 44 arranged around the plasma source 31 is energized to generate a magnetic field having a magnetic flux density of 50 to 300 gauss inside the plasma source.

The plasma generated by the plasma source 31 is
The vacuum chamber 32 is generated by the magnetic field generated by the coil 44.
Out in the direction φ. The material gas introduced from the gas nozzle 35 is decomposed and dissociated by plasma, and a reaction film is deposited on the substrate 41.

In the conventional plasma CVD apparatus as described above, the substrate 41 is arranged in the discharge region so as to face the plasma source 31, and the reaction film is deposited. Therefore, the substrate 41 is always directly exposed to plasma. There is. Therefore, the temperature rise of the substrate 41 is unavoidable due to the impact of high-energy electrons existing in the plasma, and when an aluminum plate, for example, is used as the substrate 41, the melting temperature (about 660 ° C.) or higher is reached in a few minutes. For this reason, the conventional plasma CVD apparatus as shown in FIG. 2 can form the reaction film only on the substrate that can withstand high temperature.

In order to determine that the main cause of the substrate temperature rise during film formation is the impact of high-energy electrons existing in the plasma, a Faraday cup (detector for collecting charged particles) is attached to the substrate 41. Installed near the
The energy of plasma electrons incident on the substrate was measured.
The measurement was performed under the following conditions.

The diameter D of the hole through which the charged particles of the Faraday cup pass is D = 5.0 mm (hence the area S of the hole is S≈0.2c).
m ² ), the gas pressure of N ₂ in the vacuum chamber 32 P _N2 = 7 × 10 ⁻⁴
Torr, anode voltage V _A = 55 V, discharge current I _d = 50
A, current of coil 44 I ₄₄ = 1.4 A, bias voltage −
50V. As a result of the measurement, in the conventional plasma CVD apparatus shown in FIG. 2, as shown by a curve A in FIG.
It was found that electrons with a high energy of 8 eV were incident. Incidentally, in the device of the present invention described in detail later, as shown by the curve B, the energy of the electrons incident on the substrate is 2 eV. From this measurement result, it was found that the main factor for raising the temperature of the substrate during film formation was the impact of high-energy electrons in plasma.

[0009]

In the conventional plasma CVD apparatus as described above, the substrate temperature is not significantly increased by the impact of high-energy electrons in the plasma, and the substrate material to be formed is significantly limited. is there.

According to the present invention, the plasma is converged by a converging magnetic field generating coil to be confined in a beam shape, and the substrate to be formed is distributed to the outside of the discharge region at the outer peripheral portion of the beam plasma in the radial direction. Is prevented from being bombarded by high-energy electrons existing in the plasma, the temperature of the substrate is prevented from rising, and it is difficult to form a film in the past. An object is to obtain a plasma CVD apparatus capable of forming a film even on a substrate made of a material having low heat resistance such as resin.

[0011]

Means for Solving the Problems Plasma CVD of the present invention
The apparatus was provided with a vacuum chamber that was depressurized and grounded, a plasma source that was electrically insulated from the vacuum chamber, and a plasma source connected to the plasma source at an end of the vacuum chamber. A plasma reflection electrode, a first coil disposed at least around the plasma source to generate a magnetic field for promoting arc discharge in the plasma source, and the plasma reflection electrode disposed around the plasma reflection electrode; A magnetic field that confines the plasma into a beam between the second
It is equipped with a coil. The substrate to be processed is arranged at the outer peripheral portion of the beam-shaped plasma in the radial direction and outside the discharge region.

[0012]

In the plasma CVD apparatus of the present invention, due to the action of the magnetic field generated by the second coil, the plasma is confined between the plasma source and the reflection electrode in a beam shape, and the substrate is the outer periphery of the beam plasma in the radial direction. Since it is arranged in a partial area and outside the discharge region, the substrate is suppressed from being bombarded by high-energy electrons in plasma, and the temperature of the substrate is prevented from rising during film formation.

[0013]

EXAMPLE A plasma CV of the present invention will be described below with reference to the drawings.
The D device will be described. FIG. 1 is a diagram showing a structure of a main part of an embodiment of a plasma CVD apparatus of the present invention, in which 1 is a plasma source, 2 is a vacuum chamber, and both are electrically insulated through an insulator 15. Are combined. The plasma source 1 includes a hot cathode 3, an anode 4, a deceleration electrode 16, and Ar, N ₂ and H.
_2, gas nozzle 5 for introducing a discharge gas into the plasma source 1, such as H _e is provided.

The hot cathode 3 is made of a high melting point material such as Ta, Mo or W, and is red-heated by the hot cathode heating power source 6. As the hot cathode heating power source 6, a power source having a power capacity of about 20 V and 100 A is used. The hot cathode heating power source 6 may be either a DC power source or an AC power source, but in the illustrated embodiment, a DC power source is used. The anode 4 is Ta, like the hot cathode 3.
Made of high melting point material such as Mo, W
0 to +100 V, preferably +, based on the potential of the hot cathode 3.
A voltage of 50V is applied. The deceleration electrode 16 is also T
It is made of a high melting point material such as a, Mo or W and is grounded. Further, the deceleration electrode 16 is 0 to +100 V, preferably +45 V, based on the potential of the hot cathode 3 by the deceleration power supply 8.
Biased to a positive voltage. Ar in the plasma source 1 as described above from the gas nozzle 5, only the discharge gas such as N _2, H _2, H _e is supplied.

The vacuum chamber 2 is connected to a vacuum pump (not shown) through an exhaust pipe 9. The vacuum chamber 2 is normally grounded. A reflection electrode 17 is installed in the vacuum chamber 2 so as to face the plasma source 1, and the reflection electrode 17 is kept at the same potential as the hot cathode 3 or at an insulation potential (floating potential). Reference numeral 10 is a substrate support, and 11 is a substrate which is an object to be processed and is mounted on the substrate support. In the substrate support base 10, the substrate 11 has a plasma source 1 and a reflective electrode 1.
The outer peripheral portion of the beam-shaped plasma formed between the outer peripheral portion and the outer peripheral portion in the radial direction is located outside the discharge region. The substrate 11 is provided on the substrate 11 by the substrate power supply 18.
A negative voltage of 0 to -1000V, preferably -100V, is applied via. When the substrate 11 is biased to 0 to a negative voltage, the ion energy reaching the substrate is controlled, and a film having high adhesion and high density is formed.

When the coating formed on the substrate 11 is conductive, the substrate 11 is negatively biased by a DC power source as in the illustrated embodiment, but when an insulating coating is formed on the substrate 11. It is desirable to apply a high frequency of 13.56 MHz, which is suitable for industrial use conditions. As is well known, when a high frequency is applied to the substrate 11, a negative self-bias voltage is generated in the substrate 11 due to the action of plasma. Therefore, the potential of the substrate 11 oscillates at 13.56 MHz around this negative self-bias voltage, An insulating film can be formed by preventing charge-up.

A heating heater 12 is used to maintain the substrate 11 at a predetermined temperature. Reference numeral 13 is a gas nozzle for introducing the material gas, and the gas nozzle 13 is arranged at a position for directly supplying the material gas in the vicinity of the substrate 11 in order to improve the effective consumption efficiency of the material gas.

A main coil 14 for generating a magnetic field that promotes electric discharge is arranged around the plasma source 1, and a current of 5 A or less, usually about 2 A, is supplied to the main coil 14 and the main coil 14 is supplied to the inside of the plasma source 1. A magnetic field having a magnetic flux density of 50 to 300 Gauss is generated in the φ direction. Due to the presence of this magnetic field, the thermoelectrons emitted from the hot cathode 3 perform a spiral motion so as to cling to the magnetic field, thereby extending the effective flight distance and lowering the operating pressure of 10 ⁻³ to 10 ⁻⁵ Torr (molecular weight). A stable discharge can be maintained even in the flow region).

With only the main coil 14, the plasma flowing from the plasma source 1 to the vacuum chamber 2 diverges as shown by the plasma flow 21 according to the magnetic field distribution of the main coil 14 as shown in FIG. Since the diverged plasma is directly sprayed onto the substrate 11, the substrate 11 is subjected to the impact of high-energy electrons as in the conventional device shown in FIG. 2 and the substrate temperature rises. In the device of the present invention, an auxiliary coil 20 for generating a converging magnetic field is provided around the reflective electrode 17. Auxiliary coil 2
As with the main coil, a current of 5 A or less, usually 2 A or less, is supplied to 0 to generate a magnetic field having a magnetic flux density of 100 to 200 gauss, for example. Due to this magnetic field, the plasma becomes 2 in FIG.
The plasma source 1 and the reflection electrode 17 are converged as shown by 2.
It is confined in a beam between and. In this case, the electrons are strongly influenced and converged by the converging magnetic field, but the ions which are several thousand times heavier than the electrons are hardly influenced by the converging magnetic field and head toward the substrate 11 by diffusion.

An example of forming a silicon nitride film on the substrate 11 in the above plasma CVD apparatus of the present invention will be described. A tungsten wire having a diameter of 0.8 mm is used as the hot cathode 3, and a hot cathode heating power source 6 supplies 16 V
Power of 5 A is supplied to make the hot cathode 3 glow red at 2000 ° C. or higher. Further, the hot cathode 3 is connected to the anode 4 by the anode power source 7.
A voltage of +50 V is applied with reference to the potential of +, and the deceleration power source 8 applies + to the deceleration electrode 16 with reference to the potential of the hot cathode 3.
A voltage of 45V is applied. Further, the main coil 14 has 1.
A current of 1.0 A is applied to the auxiliary coil 20 of 4 A to generate magnetic fields of about 150 gauss and about 100 gauss, respectively. As the substrate 11, SK-3 is 10 mm × 10 mm ×
A square piece cut into 40 mm was used.

Nitrogen gas is supplied from the discharge gas nozzle 5 for 50 s.
cc / min, silane gas (SiH from the material gas nozzle 13
₄ ) is supplied at a rate of 40 scc / min. The pressure in the vacuum chamber 2 at this time is 7 × 10 ⁻⁴ Torr. Under the above conditions, an emission of thermionic current of about 0.5 to 1 mA is obtained by the anode 4, and the nitrogen gas introduced into the plasma source 1 is ionized by this emission to 1 to 100
A beam-shaped plasma having an arc discharge current of A, preferably about 50 A, is formed on the axis between the plasma source 1 and the reflective electrode 17. A silicon nitride (Si ₃ N ₄ ) film of about 3 μm was formed on the substrate 11 by the film forming operation for about 1 hour.
During the film forming operation, the temperature of the substrate 11 was maintained at 180 ° C. or lower, and no thermal damage to the substrate such as the hardness of the base material due to high temperature was observed. By appropriately changing the type of gas supplied, Si ₃ N ₄ coating as well as Si
A coating film of C, TiN, TiC, BN, carbon or the like can be formed.

With the plasma CVD apparatus of the present invention, a Faraday cup was installed in the vicinity of the substrate 11 as in the conventional apparatus, and the energy of plasma electrons incident on the substrate 11 was measured. The measurement was performed under the same measurement conditions as those of the conventional device shown in FIG. However, the voltage V of the deceleration electrode 16
_DEC = 50 V, current of the main coil ₁₄ I 14 = 1.4A, and the current I ₂₀ = 1.0A auxiliary coil 20. as a result,
As shown by the curve B in FIG. 3, it was confirmed that the energy of the electrons incident on the substrate 11 was 2 eV, which was reduced to 1/20 or less as compared with the conventional device. Although the ion energy incident on the substrate 11 is not shown in the figure, there is no great difference between the apparatus of the present invention shown in FIG. 1 and the conventional apparatus shown in FIG. From this, according to the plasma CVD apparatus of the present invention, it is possible to form a film on the substrate while maintaining the substrate at a low temperature of 180 to 200 ° C or lower.

The deceleration electrode 16 used in the plasma CVD apparatus of the present invention is maintained at the ground potential, and therefore the hot cathode 3 is applied with a negative voltage of -45 V with respect to the ground potential, so that the hot cathode 3 emits. A part of the generated thermoelectrons flows into the deceleration electrode 16 and flows to the ground point. As a result, electrons are injected into the plasma due to arc discharge, and the plasma potential can be lowered to decelerate the ions. Also,
Due to the presence of the reflective electrode 17, thermionic electrons are reciprocated between the plasma source 1 and the reflective electrode 17 to oscillate the electric field, so that highly dense plasma can be efficiently generated.

FIG. 6 shows the result of measuring the ion current density with respect to the discharge current with and without the presence of the reflective electrode. The measurement conditions were such that Ar was introduced as a discharge gas and the gas pressure was P _Ar =
4.5 × 10 ⁻⁴ Torr, anode voltage V _A = 60 V, deceleration electrode voltage V _DEC = 50 V, and the potential of the reflective electrode 17 was the same as that of the hot cathode 3. As is clear from the figure, even if the discharge current has the same magnitude, a dense plasma can be obtained if the reflective electrode is present, and a large amount of ions are incident on the substrate to be processed. This is because, as described above, high density plasma can be generated by causing the thermoelectrons to reciprocate between the plasma source and the reflective electrode and causing the thermoelectrons to vibrate in the electric field.

FIG. 7 is a diagram showing the relationship between the ion current density and the current I ₂₀ supplied to the auxiliary coil 20. The measurement conditions are as follows: N ₂ is introduced as a discharge gas, and the gas pressure P _N2 = 7 ×
10 ⁻⁴ Torr, anode voltage V _A = 60 V, discharge current Id
= 8 A, deceleration electrode voltage V _DEC = 55 V, main coil current I
₁₄ = 4.0A. As is clear from the figure, it is understood that by increasing the current I ₂₀ of the auxiliary coil 20, the plasma is converged and a high density plasma is obtained, and the ion current density is increased. However, the auxiliary coil current density I
_{Since the} ion current density does not increase so much even if ₂₀ is increased to 1.5 A or more, the current I ₂₀ of the auxiliary coil ₂₀ is 1
~ 2A is suitable.

The auxiliary coil 20 has a function of converging the plasma and confining it in a beam shape as described above. As shown in FIG. 8, the second auxiliary coil 24 is provided between the main coil 14 and the auxiliary coil 20. May be provided. In addition, FIG.
As shown in FIG. 3, one large coil 25 may serve as the main coil and the auxiliary coil.

In the apparatus of the present invention, the material gas is directly supplied to the vicinity of the substrate 11 through the gas nozzle 13, but the coating film also adheres to the anode 4 and the reduction electrode 16 during the operation. When the film formed is an insulator such as Si ₃ N ₄ , the discharge current decreases as the film adheres to the anode and the moderator electrode, and the discharge eventually stops. In order to prevent the occurrence of such a situation, it is desirable to use the electrodes having the structure shown in FIG. 10 or FIG. 11 as these electrodes. 10 and 11, (a) is a sectional view,
(B) shows a front view. As for the anode 4, FIG.
Then, the anode 4 itself is electrically heated by the heating power source 28 to heat the anode 4 to a high temperature of 1800 ° C. or higher. In FIG. 11, a wire 29 made of a high melting point material having a small heat capacity is attached to a portion of the anode 4 through which the plasma 22 passes, and the wire 29 is hit by the plasma 22 to heat the anode 4 to 1800 ° C. or higher. It was done like this.
In either case, the anode surface can be exposed by re-evaporating the coating film attached to the anode 4, and the discharge current can be stabilized. It is desirable to use the deceleration electrode 16 having the structure shown in FIG. 10 or 11.

[0028]

As described above, the plasma CVD of the present invention
In the apparatus, plasma converged at high density is obtained by the reflection electrode 17 and the coil, and the substrate to be processed is arranged outside the discharge region at the outer peripheral portion in the radial direction of the plasma. There is an effect that it is possible to form a reaction film on the substrate while keeping the substrate at a low temperature of 180 ° C. to 200 ° C. by being prevented from being bombarded by energy electrons, which is impossible with the conventional apparatus. Even for a substrate made of a material having low heat resistance such as a material or a resin, a reaction film having high adhesion and denseness can be formed without causing thermal damage such as reduction in hardness. In the plasma CVD apparatus of the present invention, the restrictions on the material of the substrate 11 are greatly relaxed, so that it is possible to form a coating film on a mold, various jigs, tools, drills, chips, glass, resin and the like. Therefore, Si ₃ N ₄ , SiC, TiN, TiC, BN, carbon or the like can be formed as a coating.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a main part of an embodiment of a plasma CVD apparatus of the present invention.

FIG. 2 is a diagram showing a structure of a conventional plasma CVD apparatus.

FIG. 3 shows the energy of electrons incident on a substrate and plasma C of the present invention in a conventional plasma CVD apparatus.
It is the figure which compared and showed the magnitude | size of the energy of the electron which injects into a board | substrate in a VD apparatus.

FIG. 4 is a diagram showing a state of a plasma flow in a conventional plasma CVD apparatus.

FIG. 5 is a diagram showing a state of a plasma flow in the plasma CVD apparatus of the present invention.

FIG. 6 is a diagram showing a relationship between a discharge current and an ion current density with and without a reflection electrode 17.

FIG. 7 is an auxiliary coil 20 in the plasma CVD apparatus of the present invention.
It is a figure which shows the relationship of the electric current and ion current density which are supplied to.

FIG. 8 is a schematic configuration diagram of another embodiment of the plasma CVD apparatus of the present invention.

FIG. 9 is a schematic configuration diagram of still another embodiment of the plasma CVD apparatus of the present invention.

FIG. 10 is a schematic diagram showing an example of an anode and a moderator electrode used in the plasma CVD apparatus of the present invention.

FIG. 11 is a schematic view showing another example of the anode and the moderator electrode used in the plasma CVD apparatus of the present invention.

[Explanation of symbols]

 1 Plasma Source 2 Vacuum Tank 3 Hot Cathode 4 Anode 5 Discharge Gas Nozzle 6 Hot Cathode Heating Power Supply 7 Anode Power Supply 8 Deceleration Power Supply 9 Exhaust Pipe 10 Substrate Support 11 Substrate 12 Heating Heater 13 Material Gas Nozzle 14 Main Coil 15 Insulator 16 Deceleration Electrode 17 Reflective electrode 18 Substrate power supply 20 Auxiliary coil

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[Procedure amendment]

[Submission date] September 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

The vacuum chamber 32 is connected to a vacuum pump (not shown) through an exhaust pipe 39. The vacuum chamber 32 is grounded. In the vacuum chamber 32, a substrate support base 40 is provided in the discharge region so as to face the plasma source 31, and a substrate 41, which is an object to be processed, is placed on the substrate support base. The substrate 41 is biased by the substrate power source 42 via the substrate support 40 to 0 to -1000V, usually about -100V. 43 is a heater, which is a substrate 41
Is heated to a predetermined temperature.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

According to the present invention, the plasma is converged by the converging magnetic field generating coil and confined in a beam shape, and the substrate to be formed is arranged outside the discharge region at the outer peripheral portion in the radial direction of the beam plasma.
By placing the substrate, it is possible to prevent the substrate from being bombarded by high-energy electrons existing in the plasma and to prevent the temperature of the substrate from rising, so that it is difficult to form a film at 200 ° C. An object of the present invention is to obtain a plasma CVD apparatus capable of forming a film even on a substrate made of a material having low heat resistance such as a SK material or a resin that blunts before and after.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

Means for Solving the Problems Plasma CVD of the present invention
The apparatus was provided with a vacuum chamber that was depressurized and grounded, a plasma source that was electrically insulated from the vacuum chamber, and a plasma source connected to the plasma source at an end of the vacuum chamber. A plasma reflection electrode, a first coil disposed at least around the plasma source to generate a magnetic field for promoting arc discharge in the plasma source, and the plasma reflection electrode disposed around the plasma reflection electrode; A magnetic field that confines the plasma into a beam between the second
It is equipped with a coil. The substrate to be processed is arranged at the outer peripheral portion of the beam-shaped plasma in the radial direction and outside the discharge region.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Nitrogen gas is supplied from the discharge gas nozzle 5 for 50 s.
cc / min, silane gas (SiH from the material gas nozzle 13
₄ ) is supplied at a rate of 40 scc / min. The pressure in the vacuum chamber 2 at this time is 7 × 10 ⁻⁴ Torr. Under the above conditions, the anode 4 produces an emission of a thermoelectron current of about 0.5 to 1 mA, and the nitrogen gas introduced into the plasma source 1 is ionized by this emission to 1 to 10 mA.
A beam-shaped plasma having an arc discharge current of 0 A, preferably about 50 A, is formed on the axis between the plasma source 1 and the reflective electrode 17. A silicon nitride (Si ₃ N ₄ ) film of about 3 μm was formed on the substrate 11 by the film forming operation for about 1 hour. During deposition work, the temperature of the substrate 11 is maintained at 180 ° C. or less, thermal damage to the substrate, such as a low under the base material hardness in high temperature was observed. By appropriately changing the type of gas supplied, Si ₃ N ₄ coating as well as Si
A coating film of C, TiN, TiC, BN, carbon or the like can be formed.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

The deceleration electrode 16 used in the plasma CVD apparatus of the present invention is maintained at the ground potential, and therefore the hot cathode 3 is applied with a negative voltage of -45 V with respect to the ground potential, so that the hot cathode 3 emits. A part of the generated thermoelectrons flows into the deceleration electrode 16 and flows to the ground point. As a result, electrons are injected into the plasma due to arc discharge, and the plasma potential can be lowered to decelerate the ions. Also,
The presence of the reflective electrode 17, by the thermal electrons back and forth between the plasma source 1 and the reflective electrode 17 is electric field vibrations can be efficiently produced with a high density plasma.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

In the apparatus of the present invention, the material gas is directly supplied to the vicinity of the substrate 11 through the gas nozzle 13, but the coating film also adheres to the anode 4 and the reduction electrode 16 during the operation. When the formed film is an insulator such as Si ₃ N ₄ , the discharge current decreases as the film adheres to the anode and the moderator electrode, and the discharge eventually stops. In order to prevent the occurrence of such a situation, it is desirable to use the electrodes having the structure shown in FIG. 10 or FIG. 11 as these electrodes. 10 and 11, (a) is a sectional view,
(B) shows a front view. As for the anode 4, FIG.
Then, the anode 4 itself is electrically heated by the heating power source 28 to heat the anode 4 to a high temperature of 1800 ° C. or higher. Figure 11 is made heat capacity of a refractory material tension smaller wire 29 in a portion where the plasma 22 of the anode 4 passes, heated pounding the wire 29 in the plasma 22, the wire
29 is heated to 1800 ° C. or higher. In any of the examples, the anode surface and the wire surface can be exposed by re-evaporating the coating film attached to the anode 4 and the wire 29 , and the discharge current can be stabilized.
It is desirable to use the deceleration electrode 16 having the structure shown in FIG. 10 or 11.

Claims (5)

[Claims] 1. A vacuum chamber that is decompressed and grounded, a plasma source coupled to the vacuum chamber in an electrically insulated state, and an end portion of the vacuum chamber facing the plasma source. A plasma reflecting electrode, a first coil disposed around at least the plasma source to generate a magnetic field for promoting arc discharge in the plasma source, and the plasma disposed near the plasma reflecting electrode. A plasma CVD apparatus comprising a second coil for generating a magnetic field for confining the plasma in a beam shape between the source and the reflection electrode, and the substrate being arranged at a radial outer peripheral portion of the beam plasma and outside the discharge region. . 2. A plasma source is provided with a hot cathode that emits thermoelectrons, an anode to which a positive voltage is applied with reference to the potential of the hot cathode, and a positive voltage with respect to the potential of the hot cathode and which is grounded. A deceleration electrode maintained at a potential and a gas nozzle for introducing a gas for generating discharge to the plasma source are provided, and the vacuum chamber is provided with a gas nozzle for introducing a material gas in the vicinity of the substrate. The plasma CVD apparatus according to claim 1, which is characterized in that. 3. The plasma source and the reflective electrode are maintained at either the potential of the hot cathode or the floating potential (insulation potential), and 0 to negative voltage is applied to the substrate with reference to the ground potential. Plasma C according to claim 1.
VD device. 4. The anode and the deceleration electrode are provided with a power source for electrically heating the anode and the deceleration electrode, and by heating each electrode to a high temperature by the power source, the coating film attached to each electrode is re-evaporated to The plasma CVD apparatus according to claim 1, wherein the surface is exposed so that the discharge is maintained. 5. A wire made of a high melting point material and having a small heat capacity is stretched over the portions of the anode and the deceleration electrode through which the plasma passes, and each of these electrodes is heated by striking and heating the wire. Then, the film attached to each of these electrodes is re-evaporated to expose the surface of that electrode,
The plasma CVD apparatus according to claim 1, wherein discharge is maintained by this.