JPH01321625A - Thin film formation and device therefor - Google Patents

Abstract

PURPOSE:To reduce inclusion of impurities mixing into a film to be formed and enable formation of a semiconductor thin film excellent in characteristics at high speed and low temperature by performing evacuation of a vacuum room to attain a high vacuum while heating its wall surface when performing plasma chemical deposition, and maintaining the evacuation at the specified pressure while cooling the wall surface when forming a film on a substrate. CONSTITUTION:When supplying carrier gas to produce discharge and material gas for film formation onto the specified substrate 6 arranged in a vacuum room 3 so as to cause electron cyclrotron resonance by microwaves and magnetic field to perform plasma chemical deposition, the vacuum room 3 is evacuated into a high vacuum room 3 below 10<-3>Torr while being heated for the wall face. And when forming a film on the substrate by plasma treatment of material gas for thin film formation, the exhaust is maintained at 10<-4>-10<-2>Torr while cooling the wall face. Hereby, gas concentration in vapor phase of H2O, CO2, O2, N2, etc., at the time of film formation can be lowered by one degree of magnitude or below from a conventional device, and according to it the amounts of impurity, etc., such as O, C, N, etc., mixing into the film lowers, and it becomes possible to form a thin film excellent in characteristics.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thin film forming method and a thin film forming apparatus using plasma CVD, and particularly a thin film forming method suitable for a plasma chemical vapor deposition method using electron cyclotron resonance plasma. and a thin film forming apparatus.

[Conventional technology]

Formation of thin films by conventional electron cyclotron resonance plasma chemical vapor deposition has been described, for example, in JP-A-56-155535 and JP-A-61-47628 as examples of semiconductor thin film formation. ~10-
' After exhausting to about T orr, 10-3 to 10 bow T
The film is formed under a reduced pressure of orr, and the difference between the pressure during film formation and the pressure after evacuation before the initial plasma treatment is 10-2.
It was performed at about ~10-' Torr.

Further, the plasma processing chamber is composed of a conductive hollow container, and no special consideration is given to the walls forming the processing chamber.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not give any consideration to the incorporation of gas impurities from the processing chamber into the formed thin film, and in particular, forms thin films whose characteristics, such as semiconductor thin films, are greatly affected by the incorporation of gas impurities. Sufficient consideration has not been given to the deterioration of characteristics in some cases. For example, the vacuum level in the processing chamber before plasma processing is at most 1.
The exhaust pressure is about 0-■ Torr, and the pressure during film formation is 10"3 to 10" Torr, and the pressure difference between them is about 10-" to 10-', which is an impurity gas pressure. That was enough.

Moreover, an oil diffusion pump is used for the exhaust system, and since the oil is generally an organic substance, the film formation is performed under conditions with a high concentration of impure gas. In order to form a good thin film, it is necessary to minimize the incorporation of impurities into the film, and this is precisely the problem that the invention aims to solve. The present inventors conducted a detailed experimental study on the route of contamination of this impurity, and as a result, obtained knowledge that the problem could be solved by a relatively simple method. The present invention has been made based on this knowledge, and its purpose is to solve the above-mentioned problems.The first purpose is to form a thin film by improved electron cyclotron resonance plasma chemical vapor deposition. It is an object of the present invention to provide a method, and a second object is to provide a thin film forming apparatus for carrying out the method.

[Means to solve the problem]

The first object of the present invention is to (1) supply a carrier gas that causes discharge and a raw material gas for thin film formation onto a predetermined substrate placed in a vacuum chamber, and perform electron cyclotron resonance using microwaves and a magnetic field; When performing plasma chemical vapor deposition, the walls of the vacuum chamber must be heated to 10-" T.
a first exhaust treatment step of exhausting the air to a high vacuum chamber below orr;
When forming a film on the substrate by plasma treatment of the raw material gas for forming a thin film, while cooling the wall surface,
and (2) the substrate is made of a dielectric or a semiconductor substrate, and the thin film forming raw material is A thin film forming method characterized in that the gas contains at least a semiconductor constituent element, and a semiconductor thin film is formed on the substrate, and (3) the gas contains at least silicon as the semiconductor constituent element, and a silicon-based semiconductor thin film is formed on the substrate. (4) The semiconductor constituent element is composed of a compound semiconductor constituent element, and a compound semiconductor thin film is formed on the substrate. (5) Set the heating temperature of the wall of the vacuum chamber to 100 to 200.
℃ and the cooling temperature during film formation is below room temperature, and (6) the substrate is a semiconductor substrate, and the semiconductor constituent element is a different constituent element from the substrate. (7) The substrate is made of a dielectric material, and at least silicon is included as the semiconductor constituent element. This is achieved by a thin film forming method characterized by forming an amorphous silicon thin film on the dielectric substrate.

The second object of the present invention is to (1) form a magnetic field to cause electron cyclotron resonance in at least a portion of a vacuum chamber that is equipped with means for placing and holding a sample substrate for forming a predetermined thin film therein; An electron cyclotron resonance plasma chemical vapor deposition apparatus comprising: a means for supplying microwaves; and a means for introducing a carrier gas and a raw material gas for forming a thin film into the vacuum chamber to generate an electric discharge. A means for heating the wall surface and a means for cooling the wall surface are respectively installed on the wall surface of the vacuum chamber, and as an evacuation system for the vacuum chamber, the degree of vacuum is evacuated to a high vacuum of at least 10'' Torr or less. By means of a thin film forming apparatus characterized in that it is equipped with an exhaust system with a large exhaust capacity and a small exhaust system that maintains the exhaust capacity at 10-2 to 10-4 Torr, and (2) The means for heating the wall surface is constituted by a heater using electricity, and the cooling means provided in parallel therewith is constituted by a double partition wall provided with a passage for circulating a cooling medium in the wall surface, and the means for heating the wall surface is constituted by a double partition wall provided with a passage for circulating a cooling medium in the wall surface.

Operate the exhaust system with a large exhaust capacity to vacuum the vacuum chamber for 10 minutes.
'''@Torr is operated during the first evacuation treatment period for evacuation to a high vacuum below Torr, while the cooling means for the wall surface is operated by an evacuation system with a small evacuation capacity to reduce the degree of vacuum to 10-4 to 10-
The heating means and the cooling means for the wall surface are operated during the second evacuation treatment period during film formation to maintain evacuation at 2 Torr. The thin film forming apparatus is characterized in that it is provided with means for switching in conjunction with the second exhaust treatment period, and (3) the means for mounting and holding the sample substrate is provided with means for heating the substrate to a predetermined temperature. Achieved by a thin film forming apparatus characterized in that it is provided with at least a conductive sample stage, and is further provided with means for electrically floating in the vacuum chamber or for applying a negative potential. be done.

As the above-mentioned exhaust system, a turbo molecular pump, for example, is preferable as an exhaust system that does not use oil, and an exhaust system with a large exhaust capacity is preferably one having an exhaust speed of at least 350 Q/s or more. Furthermore, in order to maintain a high degree of vacuum in the vacuum chamber, it is desirable that the sealing surfaces of each component be sealed with metal gaskets, such as copper or gold, instead of using rubber-based materials as in conventional devices. With such a configuration, the airtightness of the vacuum chamber of the present invention can be reduced to 10-" Torr, Q/s or less in an airtightness test using He leak rate,
It is possible to maintain airtightness that is four orders of magnitude higher than the 10-' Torr, Ω/S of the conventional device. Further, the difference between the pressure in the vacuum chamber during film formation of the present invention and the pressure before introducing gases such as carrier gas and raw material gas for film formation is 10-' Torr or less, preferably to-■ Torr, as described above.
It is desirable to set it to about r.

Furthermore, in the present invention, by connecting a load-lock chamber that can be depressurized and evacuated to the vacuum chamber in order to take the sample substrate in and out of the vacuum chamber, it is possible to further reduce the molecular weight of gas mixed into the vacuum chamber.

By taking such various measures, impurities mixed into the film during film formation can be reduced as much as possible.

[Effect]

In the present invention, by setting the ultimate vacuum degree of the vacuum chamber to 10-' Torr or less, N20. When the concentration of gases such as Co2, 02°N2, etc. in the gas phase is lowered by one order of magnitude or more than in conventional devices, the amount of impurities such as 0, C, and N mixed into the film can be reduced accordingly.

As a result, it becomes possible to form a thin film with good characteristics.

Specifically, in the present invention, the N20. Reduces the molecular weight of adsorbed gases such as Co2,
More preferably, the sealing surfaces of the connection parts with various vacuum chambers are sealed with metal gaskets, so that rubber ○
The ring seal surface is kept to the minimum necessary to reduce leaks in the vacuum chamber. The heating temperature of this wall is usually 100 to 200
℃, and if the pressure is reduced in this state using an exhaust system with a large exhaust capacity, a high vacuum of 10-' Torr or less can be achieved. In addition, by loading and unloading a sample using a load-lock chamber that can be evacuated, the molecular weight of gas that enters the vacuum chamber is reduced. Furthermore, by setting the He leak rate in the vacuum chamber to IFloT orrQ/s or less, the molecular weight of gas mixed into the vacuum chamber is reduced. In electron cyclotron resonance microwave plasma chemical vapor deposition, usually 1
Film formation is performed in a pressure range of 0-4 to 10-2 Torr, but ○
In order to obtain, for example, a semiconductor film with good characteristics and less contamination of impurities such as , C, and N, the pressure before introducing gases such as carrier gas (discharge gas) and film-forming raw material gas (reactant gas) must be adjusted to It is desirable to keep the pressure at 10 -4 or lower than the current pressure, and for this purpose, it is necessary to make the vacuum chamber airtight and to provide an exhaust mechanism with a high exhaust speed. The exhaust speed of the exhaust device for this purpose is preferably 350 Q/s or more, but if you try to share the exhaust device with a high exhaust speed during film formation, there will be problems in controlling the film formation speed, so the vacuum chamber is not suitable for this purpose. It is desirable to have a dedicated exhaust system with a high exhaust speed and an exhaust system for use during film formation. Alternatively, one exhaust system with a large exhaust capacity may be shared, and exhaust valves with large and small diameters may be provided in parallel, and these valves may be used by switching. It is desirable that the above-mentioned exhaust system does not use oil in its exhaust principle in order to reduce the incorporation of C into the thin film. Specifically, turbomolecular pumps are suitable for this application.

The support base that holds the sample substrate (hereinafter simply referred to as the substrate) is at least partially made of a conductive material, and is either electrically disconnected (floating) with respect to the vacuum chamber or in a negative state with respect to the vacuum chamber. Being able to apply a potential is necessary to obtain good semiconductor properties. Due to this elliptical configuration, the substrate surface has a negative potential with respect to the plasma potential during plasma discharge, and this electric field causes ion species in the plasma to enter the substrate surface and contribute to improving film quality. JP-A-56-155535 and JP-A-61-47628
Although heating of the substrate is not required in this issue, it is important to note that the support stand that holds the substrate has a mechanism for heating the substrate, and that film formation is performed with the substrate heated in order to obtain a semiconductor thin film with good properties. is necessary.

However, when the substrate is heated during film formation, the vacuum chamber is heated due to the influence of the heat, and gas molecules such as ○, N, H, O, etc. are decomposed and produced during film formation and adsorbed on the partition walls. is desorbed and mixed into the thin film on the substrate.

In the present invention, during this film-forming period, the cooling means provided on the wall of the vacuum chamber cools the wall and serves to prevent these adsorbed gas molecules from being desorbed.

The cooling temperature is selected depending on the film forming conditions, and water, liquid nitrogen, or the like is used as the coolant.

The semiconductor thin film is formed using the above-mentioned forming apparatus with less contamination of impurities, but the pressure during film formation is 10'4 to 10-2.
It is desirable that it be Torr. In this pressure region, the mean free path of the electrons in the plasma is specified, and the energy of the electrons in the plasma is specified, which becomes the energy suitable for decomposing the reactant gas.

At least a part of the support base that holds the substrate is made of a conductive material, and when plasma discharge is started by making it electrically disconnected from the vacuum chamber, the surface of the substrate is 10 to 30% higher than the plasma potential.
It becomes a negative potential of V. 5~ for this state or vacuum chamber
When a film is formed with a negative potential of 100 V applied to the support base, ion species in the plasma enter the substrate surface, supplying appropriate energy to the film forming surface and contributing to improving film quality.

Heating the substrate during film formation is important for improving properties not only when forming polycrystalline semiconductor thin films and single crystal semiconductor thin films, but also when forming amorphous semiconductor thin films and microcrystalline semiconductor thin films. Heating the substrate during film formation has the effect of reducing the density of generated defects.

Although the method for forming semiconductor thin films described above requires heating of the substrate, the heating temperature is more than 50°C lower than that of normal thermal chemical vapor deposition or RF plasma chemical vapor deposition that uses high-frequency discharge in the radio wave range. It is possible to set.

Further, the electron cyclotron resonance plasma chemical vapor deposition method enables high-speed film formation, reduces the heating time of the substrate, and reduces the thermal history of the semiconductor thin film device. Therefore, a semiconductor thin film device with high characteristics can be obtained with fewer problems caused by thermal history such as thermal diffusion of dopants and the like.

〔Example〕

Example 1 Hereinafter, an example of the thin film forming apparatus of the present invention will be explained with reference to FIG. FIG. 1 is a partially cross-sectional explanatory schematic diagram showing the main structure of the apparatus. In the figure, 1 is a magnetron, which normally generates microwaves of 0.1 to 10 GHz.

The generated microwaves are guided by a waveguide 2 to a microwave discharge section 4' provided in a part of the vacuum chamber 3. Reference numeral 4 denotes a discharge tube, which is made of an insulator to transmit microwaves, and in this example, it is made of quartz glass. 5 is a solenoid coil for creating a magnetic field in the vacuum chamber.

6 is a sample substrate, and 7 is a sample stage having a built-in heater (not shown) as a heating mechanism. 8 is a discharge gas introduction tube as a carrier gas, and 9 is a reaction gas introduction tube as a raw material gas. The gas discharge portion 91 of the reaction gas introduction tube 9 is configured to discharge gas in the direction of the arrow of the sample substrate 6. 10 and 11 are stop valves for discharge gas and reaction gas, respectively. 12.13 is a gate valve connected to the exhaust port of the vacuum chamber, and a turbo molecular pump 14.15 is connected thereto. The pumping speed of the first turbomolecular pump 14 was 35012/s or higher, and the pumping speed of the second turbomolecular pump 15 was 150Q/s. A load lock chamber 16 is used for loading and unloading the sample substrate 6, and is connected to the vacuum chamber 3 via a gate valve 17. 18 is a turbo molecular pump for exhausting the load lock chamber.

Incidentally, the vacuum chamber 3 has a discharge tube 4 constituting a discharge section 41 in the upper part.
and a conductive hollow container 30. In this example, the hollow container 30 is made of stainless steel and has a double wall structure with partition walls 32. A refrigerant such as liquid nitrogen flows through the inlet/outlet 33a,
It circulates from 33b and constitutes the cooling means 34. 19
1 is a heating means for heating the partition wall 32, which is composed of a heater, and is capable of heating the wall surface to 100 to 200° C. and desorbing the adsorbed gas. In addition, in this device, the sealing surfaces other than the connecting part between the discharge tube 4 and the hollow container 30 and the sealing part of the vacuum gauge (all of which are omitted from the drawings) are sealed with metal gaskets, and the He leak rate of the vacuum chamber is 10-
The heating means 19 is used to bake out the wall surface of the vacuum chamber 3, and the turbo molecular pump 14
When evacuated at It has airtightness and an exhaust mechanism. Further, the sample stage 7 is electrically disconnected from the vacuum chamber 3, and the film formation is performed in this state, or the film formation is performed by applying a negative potential to the vacuum chamber 3.

Furthermore, the heating means 19 and the cooling means 34 are configured to respectively operate in conjunction with turbomolecular pumps of the exhaust system 14.15 (not shown). That is, the heating means 19
is heating the partition wall 32, the first
The turbomolecular pump 14 operates to pump the vacuum chamber 10""
Achieve a vacuum level below T orr, then close the valve 10.
．． 11 is opened and gas is supplied into the vacuum chamber to cause electron cyclotron resonance and start film formation, the heating of the wall is switched to cooling and the exhaust system is also operated by the first turbo molecule with a large exhaust capacity. Small second from pump
Switching to the turbo molecular pump 15, film formation proceeds under a reduced pressure of 10-'' to 10-' Torr while cooling the wall surface.

Note that FIG. 2 shows another example of the exhaust system, in which the turbo molecular pump 14 is configured with a large capacity one, and a valve 12 with a large exhaust conductance and a valve 13 with a small exhaust conductance are connected to the pump 14 in parallel. However, the exhaust speed is controlled by switching the valves 12 and 13. With such a configuration, it is possible to easily handle the situation by simply switching one pump and two valves with different conductances.

The actual operation of this thin film forming apparatus will be specifically explained in the following embodiment of the thin film forming method.

Example 2 Next, a case will be described in which an Si-based amorphous film and a microcrystalline film are formed using this apparatus. Before starting film formation,
The vacuum chamber is baked using the heating means 19 and the heater built into the sample stage 7 while being evacuated by the first turbo-molecular pump 14 with a high pumping speed, and the pressure in the vacuum chamber is maintained under the condition that no heating is performed by the heating means 19. 10-■To
rr or less. A sample substrate is introduced into the load lock chamber 16, and after evacuation reaches 10-' Torr, the gate valve 17 is opened, and the sample substrate 6 is placed on the sample stage 7 and heated to 200°C. At this time, the turbo molecular pump 14 with a large pumping speed
The pressure inside the vacuum chamber 3 is reduced to 10-” Torr.
After doing the following.

A discharge gas such as He, Ne, Ar, or hydrogen is supplied from the gas supply pipe 8, and a raw material gas such as monosilane gas is supplied from the gas supply pipe 9. The gate valve 12 is closed, the exhaust by the turbo molecular pump 14 with a high exhaust speed is stopped, and the exhaust is switched to the exhaust by the second turbo molecular pump 15 with a low exhaust speed, and the pressure in the vacuum chamber 3 is reduced to 10-4 to 10
−' Torr. Discharge tube 4 by magnetic coil 5
The maximum magnetic flux density of the part is 1800 Gauss, and 2.
A 45 GHz microwave of 100 W is generated by a magnetron 1, guided to a discharge tube 4 by a waveguide 2, and a plasma discharge is generated to form a film. At this time, the sample stage is electrically set at -5 to 100 V to the floating or vacuum chamber.
And so. When forming an amorphous film, use gas supply pipe 8
The discharge gas supplied from the source gas is not necessarily required, and the flow rate ratio of the discharge gas to the source gas (volume ratio=discharge gas/source gas) is about 0 to 10. The raw material gas is monosilane,
Hydrogenated gases such as disilane, germane, and methane, and gases in which hydrogen is replaced with halogen are used. Amorphous films can be formed at a high speed of 10 people/s or more.

When forming a microcrystalline film, the discharge gas is hydrogen, and the flow rate ratio of the discharge gas to the source gas is 10 or more. Depending on the type and flow rate ratio of source gas and discharge gas, the desired hydrogen-containing amorphous silicon film, *crystalline silicon film.

A silicon-germanium alloy film, a silicon carbon alloy film, etc. are obtained. The oxygen impurity concentration in the amorphous silicon film prepared by the above method is about 3×10"aI-', which can be reduced to about 1×30 compared to the case of a conventional device that exhausts the pressure in the vacuum chamber only to about 10-' Torr. The amount of impurities such as carbon and nitrogen was also reduced to about 1×10.By reducing the amount of these impurities, the space charge density in the film and the spin density due to dangling bonds were reduced to 1/2 or less.

Example 3 It was confirmed that the apparatus of the present invention can be used to form polycrystalline films and single crystal films with low impurity concentrations. In this example, hydrogen is used as the discharge gas, the flow rate ratio to the source gas (silane) is set to 10 or more, and a microcrystalline silicon film with an electron mobility of about 4al+2/v-5 is formed at a pressure of 10-4 Torr and a substrate temperature of 350°C or more. It was possible to form an epitaxially grown Si film at a substrate temperature of 450° C. or higher. In this case, the potential of the support stand that holds the sample substrate is set to -50 to -1 with respect to the vacuum chamber.
Setting the voltage to 00V was effective in lowering the microcrystalization temperature and epitaxial growth temperature.

Example 4 This example is an example of forming a compound semiconductor thin film. A GaAs substrate is used, and a single crystal is formed using the same method as in the above example by using trimethyl gallium and arsine as source gases and setting the substrate temperature to 450°C or higher. Made it grow. The obtained GaAs
When the crystalline state of the thin film was examined by electron beam diffraction, it was confirmed that it was a single crystal film.

Example 5゜This example shows five samples with different crystal lattice constants on a Si single crystal substrate.
This is an example of forming a thin film having an i-Ge superlattice structure. The Si epitaxial film could be formed at high speed under the same conditions as those for forming the Si epitaxial film in Example 3, except that the source gases were switched to silane and germane. This is because the film can be formed under conditions where the residence time of the raw material gas is short.

Example 6 This example is an example of forming a thin film having an InGaAs superlattice structure on a GaAs substrate. By using the same method as in Example 4, but by further introducing trimethylindium as a raw material gas and setting the substrate temperature to 450° C. or higher, the desired thin film could be formed.

Molecular beam epitaxy has been effective in forming thin films with a superlattice structure, but the film formation method of the present invention is more suitable for mass production in terms of film formation speed and lower temperature of the substrate, and is expected to be further developed in the future. There is expected.

Although the formation of various semiconductor thin films has been described above as an example, the present invention is not limited to these, and it goes without saying that the present invention is effective for forming thin films of other metals such as magnetic alloys.

〔Effect of the invention〕

As described above, according to the thin film forming method and apparatus of the present invention, it is possible to reduce the amount of impurities mixed into the formed film, and it is possible to form a semiconductor thin film with good characteristics at high speed and low temperature, thereby increasing the productivity of thin film semiconductor devices. This has the effect of improving the performance of the thin film semiconductor device, and also has the effect of reducing characteristic deterioration and heat deterioration due to impurity contamination of the thin film semiconductor device.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of the configuration of a thin film forming apparatus according to an embodiment of the present invention. In the figure, 1... Magnetron 2... Waveguide 3... Vacuum chamber 4... Quartz discharge tube 5... Solenoid coil 6... Sample substrate 7... Sample stand
8...Discharge gas supply pipe 9...Raw material gas supply pipe
10.11...Stop valve 12, 13.17...
・Gate valve 14, 15.18...Turbo molecular pump 16...Load lock chamber 19...Heater (heating means) 30・
...Hollow container 32...Partition wall 34...Cooling means Representative patent attorney Junnosuke Nakamura

Claims (1)

[Claims] 1. Plasma chemistry is performed by supplying a carrier gas that causes discharge and a raw material gas for forming a thin film onto a predetermined substrate placed in a vacuum chamber, and causing electron cyclotron resonance with microwaves and a magnetic field. During vapor deposition, a first exhaust treatment step is performed in which the wall surface of the vacuum chamber is heated and the vacuum chamber is evacuated to a high vacuum chamber of 10 Torr or less, and the thin film forming raw material gas is deposited on the substrate by plasma treatment. A method for forming a thin film, comprising a second exhaust treatment step in which the wall surface is cooled and the exhaust gas is maintained at 10^-^4 to 10^-^2 Torr during film formation. 2. The thin film forming method according to claim 1, wherein the substrate is made of a dielectric or a semiconductor substrate, the raw material gas for thin film formation contains at least a semiconductor constituent element, and a semiconductor thin film is formed on the substrate. 3. The thin film forming method according to claim 2, wherein the semiconductor constituent element includes at least silicon, and a silicon-based semiconductor thin film is formed on the substrate. 4. The thin film forming method according to claim 2, wherein the semiconductor constituent element is a compound semiconductor constituent element, and a compound semiconductor thin film is formed on the substrate. 5. The thin film forming method according to claim 1, wherein the heating temperature of the wall surface of the vacuum chamber is set to 100 to 200°C, and the cooling temperature during film formation is set to below room temperature. 6. Claim 2, wherein the substrate is a semiconductor substrate, the semiconductor constituent element includes a constituent element different from that of the substrate, and a semiconductor thin film having a superlattice structure is formed on the substrate. 5. The thin film forming method according to claim 3 or claim 4. 7. The method of forming a thin film according to claim 2, wherein the substrate is made of a dielectric material, contains at least silicon as the semiconductor constituent element, and an amorphous silicon thin film is formed on the dielectric substrate. 8. Magnetic field generating means and microwave supplying means are provided in at least a part of the vacuum chamber, which is equipped with means for placing and holding a sample substrate for forming a predetermined thin film therein, in order to cause electron cyclotron resonance. An electron cyclotron resonance plasma chemical vapor deposition apparatus comprising means for introducing a carrier gas for causing discharge into the vacuum chamber and a raw material gas for forming a thin film into the vacuum chamber, A means for heating the wall surface and a means for cooling the wall surface are respectively provided, and as an evacuation system for the vacuum chamber, an evacuation system with a large evacuation capacity capable of evacuation to a high vacuum of at least 10 Torr or less is provided. And 10^
A thin film forming apparatus characterized by comprising a small exhaust system that maintains the pressure at -^2 to 10^-^4 Torr. 9. The means for heating the wall surface of the vacuum chamber is constituted by a heater powered by electricity, and the cooling means provided therein is constituted by a double partition wall provided with a passage for circulating a cooling medium on the wall surface; The heating means is operated during a first evacuation process period in which an evacuation system with a large evacuation capacity is operated to evacuate the vacuum chamber to a high vacuum of 10^-■ Torr or less, while the cooling means for the wall surface is operated with a large evacuation capacity. The heating means and the cooling means for the wall surface are operated during the second evacuation treatment period during film formation in which a small evacuation system is operated to maintain the degree of vacuum at 10^-^4 to 10^-^2 Torr. and first,
9. The thin film forming apparatus according to claim 8, further comprising means for switching in conjunction with the second exhaust treatment period. 10. The means for mounting and holding the sample substrate is provided with a means for heating the substrate to a predetermined temperature, and is composed of at least a conductive sample stage, and is electrically suspended with respect to the vacuum chamber; 10. The thin film forming apparatus according to claim 8 or 9, further comprising means for applying a negative potential.