JPH0770749A - Formation of thin film and device therefor - Google Patents

Abstract

PURPOSE:To provide the formation of a thin film and a device therefor, by which the optical characteristics of the formed thin film and the thin film forming speed can be stabilized over a long period and a favorable thin film can be formed without requiring the use of a restrictedly specified substrate material and further, simplification of the process, improved productivity and reliability of the product, etc., can be attained. CONSTITUTION:In the formation of a thin film using the sputtering in the vacuum chamber 1, the H2O partial pressure in the vacuum chamber 1 is controlled at a specific value during the film formation. Alternatively, in the formation of an oxide thin film comprising the generation of a plasma in the vacuum chamber 1 and its utilization, H2O, H2O2 or their mixture is forcedly introduced into the vacuum chamber 1 and high-frequency electric power of 30 to 300MHz is applied on an arbitrary number of the discharge electrodes which are provided in the vacuum chamber 1, at the time of forming the thin film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming method and apparatus, and more particularly, to an optical thin film of an oxide such as an antireflection film or a highly reflective film on a substrate of an optical element made of glass or plastic. The present invention relates to a method and an apparatus for forming a uniform film at a stable film formation rate with good reproducibility.

[0002]

2. Description of the Related Art Conventionally, thin film formation utilizing sputtering phenomenon (hereinafter referred to as sputtering) is relatively easy to form even with a high melting point material or compound that is difficult to deposit, and it is easy to increase the area. Widely used for reasons. In such sputtering, heating (baking) of the vacuum chamber is generally performed during the sputtering in order to suppress the gas emitted from the walls of the vacuum chamber and the like in order to improve the homogeneity of the film and the film formation efficiency. . As an apparatus for performing such spatter, the conventional batch processing is used, and a single-wafer sputter apparatus equipped with a front chamber (load lock chamber), an in-line sputter apparatus, or the like, is used to suppress the gas emitted from the sputter and to reduce the vacuum in the vacuum chamber. There are ways to improve quality.

On the other hand, generally, as a method of forming an oxide thin film using plasma, there are a sputtering method, a vapor phase growth (CVD) method, an ion plating method and the like.
However, when a thin film is usually formed by these methods, the oxidation of the thin film is insufficient and the composition ratio of the film collapses, or atoms deposited without being completely bonded exist in the film. And these cause the generation of absorption optically. When such optical absorption occurs in the thin film, the antireflection film made of the thin film causes a decrease in transmittance, and a high reflection film causes a decrease in reflectance, resulting in loss of the function of the optical thin film. In particular, the shorter the wavelength of the light used, the more remarkable the tendency. Also, because it absorbs light, heat is generated in that part,
The film itself may be damaged or the underlying substrate may be distorted, resulting in a reduction in surface accuracy. Therefore, it is necessary to reduce this optical absorption as much as possible. Therefore, conventionally, the substrate is heated during film formation or after film formation to accelerate oxidation on the substrate and eliminate unbonded atoms.

[0004]

However, in the case where the above-mentioned conventional sputtering apparatus is used to form a film that requires high accuracy in film thickness and film quality such as an optical thin film, the vacuum chamber must be replaced by replacing the target or maintaining the vacuum chamber. When air leaks to the atmosphere, water in the atmosphere will be adsorbed on the walls of the vacuum chamber, etc. There is a drawback that the density (refractive index) of the film and the film formation speed change due to the effect of desorption of water from the wall of the vacuum chamber (released gas) before the film formation. Further, there is a method of baking for a sufficient time as a method of reducing the influence of the released gas, but in the case of equipment introduced into a factory, there is a problem in increasing the film formation efficiency.

Further, in the above-mentioned conventional technique of heating the substrate, the material of the substrate is limited to the heat-resistant material, and distortion may occur on the surface of the substrate. There is a problem that a cooling step is required, cost is increased, productivity is deteriorated, and reliability is reduced due to complicated manufacturing equipment.

In view of the above problems of the prior art, an object of the present invention is to provide a thin film forming method and apparatus in which the optical characteristics and the film forming rate of the thin film to be formed are stable for a long period of time and a thin film can be obtained with good reproducibility. To be able to do so. Another object is to obtain a good thin film without limiting the material of the substrate. Further, it is intended to simplify, improve productivity and reliability.

[0007]

In order to achieve the above object, according to the present invention, when a thin film is formed by sputtering in a vacuum chamber, H ₂ O or O in the vacuum chamber during film formation is formed.
The H partial pressure is controlled so as to have a predetermined value, for example, any value of 1 × 10 ⁻⁷ to 1 × 10 ⁻³ Pa.

Alternatively, when plasma is generated in a vacuum chamber and an oxide thin film is formed on the substrate by using the plasma, H ₂ O, H ₂ O ₂ or a mixture thereof is forced into the vacuum chamber. And the high frequency power of 30 to 300 MHz is applied to an arbitrary number of discharge electrodes provided in the vacuum chamber. The oxide thin film is formed by, for example, a sputtering method by supplying a rare gas as a sputtering gas and oxygen as a reaction gas into the vacuum chamber and applying discharge power to a sputtering target provided in the vacuum chamber. H forcibly supplied into the vacuum chamber
₂ O, H ₂ O ₂ or a mixture thereof is preferably vaporized. The oxide thin film is, for example, A
l ₂ O ₃ film, HfO ₂ film, ZrO ₂ film, Y ₂ O ₃ film, T
a ₂ O ₅ film, TiO ₂ film, or a mixture thereof.

[0009]

[Function] When a thin film is formed by sputtering, immediately after the target is exchanged or the vacuum chamber is leaked to the atmosphere due to maintenance of the vacuum chamber or the like, water adsorbed from the vacuum chamber or the substrate surface is desorbed due to plasma heating in the initial stage of film formation, Released
The partial pressure of water in the vacuum chamber rises. That is, the main component of the desorbed released gas is water. This released gas increases at the beginning of film formation due to plasma heating and the like, and gradually decreases with the elapse of film formation time and exhaust time. As described above, the amount of released gas fluctuates with the film formation time and the exhaust time, which affects the formation speed and film quality of the thin film during sputtering. However, according to the present invention, the water (H ₂ O) or OH partial pressure in the vacuum chamber is controlled to a certain specific value during film formation, so that the sputtered film formation rate and film quality are stabilized. Planned.

On the other hand, the CVD method including the sputtering method
Acid by using plasma by ion plating method
In the case of forming a thin oxide film,₂ 
O, H₂ O₂ Or while introducing a mixture of them
High frequency of 30 MHz to 300 MHz for the electrode
Electric power (hereinafter referred to as VHF) is applied.
Use VHF power compared to power below 30 MHz
It is used for the following reasons. That is, the plasma density
By increasing the temperature, decomposition of the introduced gas is further promoted.
And the spread of plasma in the vacuum chamber is increased.
Therefore, the reaction becomes widespread, and
Due to the small sheath thickness,
This is because damage to the substrate is reduced. Also, H₂ O or
H₂ O₂Compared to the case of oxygen gas
Activated oxygen is obtained by dissociation with low energy, and
H₂ O or H₂ O₂ Hydrogen obtained by dissociating from
This is because it bonds with atoms that it does not have and stabilizes. But
Therefore, according to the present invention, H ₂ O or H₂ O₂ Is VHF power
Efficiently decomposes to generate activated oxygen and hydrogen, which
Activated oxygen accelerates the oxidation of the thin film, and hydrogen
Remove defects. This makes it necessary to heat the substrate
In addition, a good oxide thin film having no optical absorption is formed.

[0011]

【Example】

(Embodiment 1) FIG. 1 is a block diagram showing the structure of a sputtering apparatus according to the first embodiment of the present invention. In the figure, 1 is a vacuum chamber (chamber), 2 is a target, 3 is a substrate on which a thin film is formed, 4 is a high frequency power source for applying a high frequency voltage to the target 2, 5 is a matching box, 6
Is a direct current power source connected in parallel to the high frequency power source 4 for applying a direct current voltage to the target 2, 7 is a filter for cutting high frequency, and 8 is a vacuum exhaust system for reducing the pressure in the vacuum chamber 1. The target 2 is the cathode and the substrate 3 is usually kept at ground potential. As the target 2, a metal, an alloy, an inorganic oxide, a nitride, a carbide, a fluoride or the like is used. A permanent magnet or an electromagnet as a magnetic field applying unit is provided on the back surface of the target 2 and is installed so that a balanced magnetic field is applied to the target 2. The vacuum exhaust system 8
It consists of a main exhaust turbo-molecular pump, a rough-quoted rotary pump, a main valve, a roughing valve, and an auxiliary valve.

Reference numeral 9 denotes a differential exhaust system of a quadrupole mass filter for measuring the partial pressure of H ₂ O in the vacuum chamber 1, which has the same structure as the vacuum exhaust system 8. An orifice 10 is provided between the vacuum chamber 1 and the differential exhaust system 9 to create a differential pressure between them. The orifice 10 is a hole or a variable valve having a conductance such that a pressure difference between the vacuum chamber 1 and the differential exhaust system 9 can be about 1 to 2 digits. Reference numeral 11 is a sensor part of the quadrupole mass filter, 12 is a quadrupole mass filter body, 13 is a water control circuit for controlling the supply of water into the vacuum chamber 1 based on the output of the quadrupole mass filter body 12, 14 Is a sputter gas supply system for supplying sputter gas into the vacuum chamber 1, and 15 is a water supply system for supplying water in the constant temperature bath into the vacuum chamber 1 based on a control signal from the water control circuit 13. Water supply system 15
Is composed of a water tank, a mass flow controller, a stop valve, a bypass valve, and the like. Reference numeral 16 is a leak valve for leaking the vacuum chamber 1 to the atmosphere.

Next, the operation (operation) of the apparatus will be described. First, the substrate 3 to be processed is attached, and then the vacuum exhaust system 8
Depressurize to the required pressure. At this time, the main valve of the differential exhaust system 9 is closed, exhaustion and baking are sufficiently performed, and the differential exhaust system 9 and the quadrupole mass filter sensor unit 1 are
The gas released from the wall of No. 1 is sufficiently suppressed. When the inside of the vacuum chamber 1 is depressurized to about 1 × 10 ⁻⁴ Pa, the main valve of the differential exhaust system 9 is opened, and the H ₂ O partial pressure inside the vacuum chamber 1 is measured by the quadrupole mass filter. At this time, the gas passing through the orifice 10 is measured. As experimental values, the H ₂ O partial pressure of mass number 18 was 2 × 10 ⁻⁵ Pa, and the OH partial pressure of mass number 17 was 7 × 10 ⁻⁶ Pa.

Next, in order to make the partial pressure of water in the vacuum chamber 1 constant, the water pressure in the differential exhaust system 9 is a specific value (H ₂ O partial pressure is 4 × 10 ^-5 Pa in this experiment). The control circuit 13 is set to have such a value. H measured with a quadrupole mass filter
₂ measurements of O partial pressure is input from the quadrupole mass filter body 12 in H ₂ O partial pressure in the output as an analog signal proportional control circuit 13. The control circuit 13 compares the input value with the set value, and outputs a control signal to the water supply system 15 such that the input value approaches the set value. The water supply system 15 introduces water proportional to this control signal into the vacuum chamber 1. This control loop keeps the H ₂ O partial pressure in the vacuum chamber 1 constant.

The temperature in the constant temperature bath is adjusted so as to be maintained at 50.degree. The temperature controller and the control circuit 13 used for that purpose are most preferably of a PID-controlled continuous output control system.

As described above, the sputter gas is introduced into the vacuum chamber 1 from the sputter gas supply system 14 in a state where the H ₂ O partial pressure in the vacuum chamber 1 is controlled to a specific value. An inert gas such as argon is used as the sputtering gas.
When performing reactive sputtering, reactive gas such as oxygen, nitrogen, methane can be mixed with the sputtering gas. At this time, the degree of vacuum in the vacuum chamber 1 is preferably 1 × 10 ⁻¹ to ¹ Pa by introducing a certain amount of sputtering gas into the vacuum chamber.

Next, a DC voltage is applied to the target 2. Note that only the DC voltage may be applied to the target 2, the high frequency voltage may be applied while being superimposed on the DC voltage, or only the high frequency voltage may be applied. By applying the voltage to the target 2 in this manner, glow discharge is generated. This glow discharge forms plasma in the discharge space. The positive ions in the plasma are accelerated by the voltage drop in the vicinity of the target 2 which is the cathode and collide with the surface of the target 2 to sputter vaporize the surface of the target 2. The sputtered thin film formation is deposited on the substrate 3 to form a thin film.

Table 1 shows that the SiO ₂ film and Al
Refraction with respect ₂ O ₃ film of water during sputtering in the case of film formation (H ₂ O) partial pressure amount Wavelength 400nm of films formed with film forming speed for the (H ₂ O partial pressure in the differential pumping system 9) Indicates the rate. An SiO ₂ target was used for the SiO ₂ film and an Al target was used for the Al ₂ O ₃ film, and both were formed with a mixed gas of argon and oxygen. If the partial pressure of H ₂ O in the sputtering is small, the film formation rate becomes faster cases SiO ₂ film, Al ₂ O ₃ film and a refractive index of the film quality, SiO ₂
It tends to decrease in the film and increase in the Al ₂ O ₃ film. Characteristic values shown in Table 1 is a value obtained when the three values indicated of H ₂ O partial pressure control setting values set in the Table 1, respectively in the control circuit 13, of H ₂ O partial pressure In the conventional case where no control is performed, the film formation rate and the film quality change as shown in Table 1 with evacuation and film formation time.

[0019]

[Table 1] (Embodiment 2) In the sputtering apparatus of Embodiment 1, even if the OH partial pressure amount of mass number 17 is measured as the measurement gas species in the vacuum chamber 1 and the same loop control as in Embodiment 1 is performed, the same effect is obtained. was gotten.

(Embodiment 3 and Comparative Examples 1 to 3) FIG. 2 is a block diagram schematically showing an oxide thin film forming apparatus according to a third embodiment of the present invention. As shown in the figure, in this apparatus, the vacuum chamber 1 is kept vacuum by a vacuum pump 102, and Ar and O ₂ are introduced into the vacuum chamber 1 via gas flow meters 103 and 104. ing. Further, H ₂ O 107 is vaporized in a constant temperature bath 106 at about 50 ° C. and then similarly introduced through a flow meter 105. Further, in this embodiment, since the sputtering method was attempted to be created, the target 2 which is the material of the thin film was placed in the vacuum chamber 1, and a high frequency (hereinafter, referred to as RF) of 13.56 MHz was applied thereto. Power is supplied from the high frequency power supply 109 and the DC power supply 110 that output the power.
Then, the discharge electrode 1 to which the power of the VHF power supply 111 is applied
12 parallel to the substrate 3 which can rotate in the vacuum chamber 1,
Moreover, it is installed at a position vertical to the target 2. A crystal vibration type film thickness meter 114 is used to control the film thickness of the thin film.

Using this apparatus, an attempt was made to form a thin film of Al ₂ O ₃ by using aluminum as the material of the target 2 and the discharge electrode 112 and synthetic quartz glass as the material of the substrate 3. That is, first, the vacuum chamber 1 is evacuated to about 10 ⁻⁵ Pa (Pascal) with the vacuum pump 102, 150 sccm of O ₂ is introduced through the flow meter 104, and H ₂ O is further introduced through the flow meter 105. 0.25 sccm was introduced and the total pressure was reduced to 0.
It was about 13 Pascal. After the gas becomes stable, RF power of 500 W and DC power of 1560 W (2
(60 V, 6.0 A) was applied to cause discharge, and 100 W of VHF power was applied to the discharge electrode 112. Then, an Al ₂ O ₃ film was formed by indirectly monitoring the film thickness on the substrate 3 with a crystal vibrating film thickness meter 114 until the film thickness was about 160 nm. Then, the transmittance and reflectance of the film were measured by a spectroscopic measurement method, and the optical absorption of the film was calculated from the measured values and expressed as an extinction coefficient. In this example, KrF
Since the purpose was to create a laser antireflection film,
The measurement wavelength was 248 nm. The results are shown in Table 2 as Example 3.

[0022]

[Table 2] In addition, when the VHF power is not input in the above,
If you do not introduce H ₂ O, if not carried out both on and of H ₂ O introduced the VHF power, the Al ₂ O ₃ film was formed in the same manner for each to determine the extinction coefficient. The results are shown in Table 2 as Comparative Examples 1 to 3, respectively.

From Table 2, it is understood that the optical absorption can be eliminated only in the case of Example 3 in which H ₂ O and VHF electric power were simultaneously introduced.

(Example 4) Al thus obtained
_A total of 6 layers of a ₂ O ₃ film and a non-absorption SiO ₂ film obtained in the same manner are alternately deposited on a synthetic quartz substrate to form a KrF film.
Laser wavelength 248 nm and He-Ne laser wavelength 63
An antireflection film for two wavelengths of 3 nm was prepared. The structure of the film is shown in Table 3 together with the refractive index and optical film thickness of each layer.

[0025]

[Table 3] The reflection characteristics of this antireflection film are shown in FIG. Also,
The absorption characteristics of this antireflection film are shown in FIG. As can be seen from FIG. 4, it was possible to obtain a good film having no absorption over a wide range of wavelengths from 220 nm to 700 nm.

(Example 5 and Comparative Examples 4 to 6) A thin film of HfO ₂ was formed and erased in the same manner as in Example 3 and Comparative Examples 1 to 3 except that the materials for the target 2 and the discharge electrode 112 were hafnium. The extinction coefficient was calculated. The results are shown in Table 4 as Example 5 and Comparative Examples 4 to 6, respectively.

[0027]

[Table 4] From Table 4, it can be seen that the optical absorption can be eliminated only in the case of Example 5 in which H ₂ O and VHF power were introduced at the same time.

(Example 6 and Comparative Examples 7 to 9) The same as Example 3 and Comparative Examples 1 to 3 except that zirconium was used as the material of the target 2 and the discharge electrode 112 and the measurement wavelength was 365 nm. A ZrO ₂ thin film was formed and the extinction coefficient was determined. The results are shown in Table 5 as Example 6 and Comparative Examples 7 to 9, respectively. The measurement wavelength is 365n
The reason for setting m is that the ZrO ₂ thin film is intended to be used at a wavelength of i-line of 365 nm.

[0029]

[Table 5] From Table 5, it can be seen that the optical absorption can be eliminated only in the case of Example 6 in which H ₂ O and VHF power were simultaneously introduced.

(Example 7 and Comparative Examples 10 to 12) Y ₂ was carried out in the same manner as in Example 6 and Comparative Examples 7 to 9 except that yttrium was used as the material for the target 2 and the discharge electrode 112.
A thin film of O ₃ was formed. The results are shown in Table 6 as Example 7 and Comparative Examples 10 to 12, respectively.

[0031]

[Table 6] From Table 6, it can be seen that the optical absorption can be eliminated only in the case of Example 7 in which H ₂ O and VHF power were simultaneously introduced.

Further, by introducing H ₂ O and VHF electric power at the same time, optical absorption could be eliminated even in the Ta ₂ O ₅ and TiO ₂ films.

(Example 8 and Comparative Example 13) Next, VHF
An example in which a thin film is uniformly formed on a substrate having a curvature by utilizing the fact that plasma is spread over a wide range when electric power is introduced will be described. That is, as the substrate 3, two convex and two concave lenses each having a curvature and an outer diameter as shown in Table 7 were used, and H ₂ O was not introduced in order to confirm only the effect of plasma spread. A thin film was formed in the same manner as in Example 3 except for the above. Then, the distribution of the thickness of the film formed on the lens surface was measured. The results are shown in Table 7 as Example 8.

Further, a thin film was formed in the same manner as in Example 8 except that VHF power was not introduced, and the film thickness distribution was measured. The results are shown in Table 7 as Comparative Example 13.

[0035]

[Table 7] From Table 7, it is understood that the film thickness distribution amount is improved by the introduction of the VHF electric power in any of the substrate 3 shapes.

[0036]

As described above, according to the present invention, when a thin film is formed by sputtering, the partial pressure of H ₂ O in the vacuum chamber during film formation is controlled to a predetermined value. The H ₂ O partial pressure in the vacuum chamber can be kept constant without being affected by the gas discharged from the wall of the vacuum chamber, etc., the amount of which varies with the evacuation time and the film formation time. The film quality, especially the film density (refractive index), can be stabilized significantly longer than in the past. Further, when a multilayer film such as an optical film is formed, the film thickness monitor is conventionally used to control the film thickness.
Since the film formation speed is stable, sufficient stability and reproducibility can be obtained only by controlling the film thickness by the film formation time.
Therefore, maintenance for opening the vacuum chamber to the atmosphere, such as replacement of the film thickness monitor, is not required, so that long-term continuous film formation is possible, the operating rate of the film forming apparatus is improved, and the cost can be reduced. Further, in obtaining the optical characteristics of the obtained multilayer film, since the film is homogeneous, it is in good agreement with the simulation calculation value, and the characteristics can be finished in a short time.

On the other hand, in the case of forming an oxide thin film by utilizing plasma such as CVD method or ion plating method including sputtering method, H ₂ O in a vacuum chamber,
H ₂ O ₂ or a mixture thereof is forcibly supplied, and 30 to 300 is applied to any number of discharge electrodes provided in the vacuum chamber.
Since the high frequency power of megahertz is applied, a good oxide thin film without optical absorption can be formed at a low temperature.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a sputtering apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram schematically showing an oxide thin film forming apparatus according to a third embodiment of the present invention.

FIG. 3 is a reflection characteristic diagram of an antireflection film formed in a fourth example of the present invention.

4 is an absorption characteristic diagram of the antireflection film of FIG.

[Explanation of symbols]

1: vacuum chamber (chamber), 2: target, 3: substrate,
4, 109: high frequency power supply, 5: matching device, 6, 110: direct current power supply, 7: filter for cutting high frequency, 8: vacuum exhaust system, 9: differential exhaust system of quadrupole mass filter, 10: orifice, 11: Sensor part of quadrupole mass filter, 1
2: Quadrupole mass filter body, 13: Water control circuit, 1
4: Sputter gas supply system, 15: Water supply system, 16: Leak valve, 102: Vacuum pump, 103, 104, 1
05: gas flow meter, 107: H ₂ O, 106: constant temperature bath,
111: VHF power supply, 112: discharge electrode, 114: crystal vibration type film thickness meter.

Claims (14)

[Claims] 1. A method for forming a thin film by sputtering in a vacuum chamber, wherein H ₂ in the vacuum chamber during film formation is used.
A method for forming a thin film, characterized in that the O partial pressure is controlled to be a predetermined value. 2. A method of forming a thin film by sputtering in a vacuum chamber, wherein OH in the vacuum chamber during film formation is used.
A method for forming a thin film, characterized in that the partial pressure is controlled to a predetermined value. 3. The predetermined value is 1 × 10 ⁻⁶ to 1 × 10 ⁻³ P
The thin film forming method according to claim 1 or 2, wherein the value is either a. 4. An apparatus for forming a thin film by sputtering in a vacuum chamber, comprising means for controlling the H ₂ O partial pressure in the vacuum chamber to a predetermined value. Thin film forming equipment. 5. An apparatus for forming a thin film by sputtering in a vacuum chamber, comprising means for controlling the OH partial pressure in the vacuum chamber to a predetermined value. apparatus. 6. The predetermined value is 1 × 10 ⁻⁷ to 1 × 10 ⁻⁴ P
The thin film forming apparatus according to claim 4, wherein the thin film forming apparatus has a value of a. 7. A method of forming an oxide thin film using plasma generated in a vacuum chamber, wherein H ₂ O, H ₂ O ₂ or a mixture thereof is forced into the vacuum chamber when the thin film is formed. And a high frequency power of 30 to 300 MHz is applied to an arbitrary number of discharge electrodes provided in the vacuum chamber. 8. The oxide thin film is formed by supplying a rare gas as a sputtering gas and oxygen as a reaction gas into the vacuum chamber, and applying discharge power to a sputtering target provided in the vacuum chamber to perform sputtering. The thin film forming method according to claim 7, which is performed by a method. 9. H ₂ forcibly supplied into the vacuum chamber
8. The thin film forming method according to claim 7, wherein O, H ₂ O ₂ or a mixture thereof is vaporized. 10. The oxide thin film is an Al ₂ O ₃ film, H
The thin film forming method according to claim 7, which is a fO ₂ film, a ZrO ₂ film, a Y ₂ O ₃ film, a Ta ₂ O ₅ film, a TiO ₂ film, or a mixture thereof. 11. A thin film forming apparatus comprising a vacuum chamber, means for generating plasma in the vacuum chamber, and means for forming an oxide thin film by using the plasma, wherein H ₂ O and H ₂ are contained in the vacuum chamber. It is provided with a means for forcibly supplying O ₂ or a mixture thereof, an arbitrary number of discharge electrodes provided in the vacuum chamber, and means for applying a high frequency power of 30 to 300 MHz to the discharge electrodes. Thin film forming apparatus. 12. The oxide thin film forming means supplies a rare gas as a sputtering gas and oxygen as a reaction gas into the vacuum chamber, a sputtering target provided in the vacuum chamber, and a discharge power to the target. The thin film forming apparatus according to claim 11, further comprising a means for applying a thin film to form a thin film by a sputtering method. 13. The H forcibly supplied into the vacuum chamber.
The thin film forming apparatus according to claim 11, wherein ₂ O, H ₂ O ₂ or a mixture thereof is vaporized. 14. The oxide thin film is an Al ₂ O ₃ film, H
The thin film forming apparatus according to claim 11, which is an fO ₂ film, a ZrO ₂ film, a Y ₂ O ₃ film, a Ta ₂ O ₅ film, a TiO ₂ film, or a mixture thereof.