JPH0318500Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The thin film forming apparatus according to the invention is an apparatus for forming dielectric multilayer optical films, but it is also used for forming decorative surface coatings and electrodes of various electrical parts. It is also an extremely useful device for film formation of optical disks. Furthermore, since it is possible to form superlattice thin films by using a suitable single crystal substrate as a substrate for thin film formation, this thin film forming apparatus plays a major role in establishing new industrial fields.

[Summary of the idea]

The thin film forming apparatus according to the present invention has at least two electron beam heating vapor deposition sources arranged in a vacuum chamber, a shutter control mechanism that can independently cut off or release the raw material vapor from each vapor deposition source, and reactant gas. A substrate heating mechanism with an inlet that can raise the substrate temperature to over 300℃ and a light intensity of 1mW/cm ² on the substrate surface.
At least by arranging ultraviolet lamps that can
While irradiating the substrate with ultraviolet rays in a vacuum chamber evacuated to below 10 ^-3 torr or in a reaction gas chamber,
In addition, by alternately evaporating different substances from at least two electron beam heating type evaporation sources while the substrate is heated, it is possible to form a homogeneous and highly adhesive multilayer film.

[Conventional technology]

Conventionally, dielectric multilayer optical films are made by depositing the substrate in a vacuum chamber.
It is formed by evaporating different materials alternately in a high vacuum or in a reactive gas from multiple electron beam heating evaporation sources or multiple resistance heating evaporation sources while heating to 200°C to 350°C. is a known technique. Also, to increase the adhesion of the film,
Devices having a mechanism for converting vapor from an evaporation source into plasma or for irradiating a substrate with an ion beam are already commercially available.

[Problem that the invention attempts to solve]

However, in the above-mentioned thin film forming apparatus, especially the mechanism that increases the adhesion of the film, it is necessary to use expensive equipment such as a high frequency power source or a high voltage power source, and the mechanism is also highly dangerous to the human body when handled. The problem was that it had to be done. The thin film forming apparatus according to the present invention solves the above problems and provides an inexpensive and safe thin film forming apparatus having a mechanism for increasing the adhesion of the film.

[Means for solving problems]

The thin film forming apparatus according to the present invention has a mechanism that increases the adhesion of the film, and the light intensity at the substrate surface is 1 m.
An ultraviolet lamp capable of producing at least W/cm ² is installed, and the substrate is irradiated with ultraviolet rays in a vacuum chamber or reaction gas tank evacuated to at least 10 ^-3 torr or less, and the substrate is heated for at least 2 hours. By alternately evaporating different materials from two or more electron beam heating type evaporation sources, it is possible to form a homogeneous and highly adhesive multilayer film, thereby solving the above problems.

〔Example〕

Next, a thin film forming apparatus according to the present invention will be described with reference to the drawings and examples. The figure is a configuration diagram of the thin film forming apparatus according to the present invention, in which 1 is a vacuum chamber, 2 is a substrate heating heater, 3 is a crystal resonator type film thickness monitor, 4 is a shutter, 5 is an exhaust port, and 6 is an electron beam heating type. An evaporation source, 7 a vacuum gauge, 8 a substrate holder, 9 a substrate, 10 a thermocouple, 11 an ultraviolet lamp, and 12 a reaction gas inlet. The gas pressure in the vacuum chamber 1 is measured by a vacuum gauge 7, and air is supplied to the vacuum chamber 1 through an exhaust port 5 using a combination of an oil diffusion pump, a cryopump, or a turbo pump and an oil rotary pump. The substrate 9 is attached to the substrate holder 8 with screws or springs, and the substrate temperature is measured with a thermocouple 10. Although the substrate heating heater 2 is used for heating the substrate, a W lamp, a halogen lamp, etc. may also be used. Ultraviolet lamp 1 is used to irradiate the substrate with ultraviolet rays.
1, and the intensity of ultraviolet light on the substrate surface is measured in advance in relation to the power supply voltage of the ultraviolet lamp 11, and is measured by measuring the power supply voltage applied to the ultraviolet lamp 11. The evaporation raw material is set in two electron beam heating type evaporation sources and is heated and melted by the electron beam. The selection of the thin film material to be formed on the substrate 9 is performed by opening and closing the shutter 4. That is, the evaporation raw material with the shutter 4 open is formed as a thin film on the substrate 9, and when both shutters are open, a mixed thin film of the raw materials set in both electron beam heating evaporation sources is formed, and both shutters are open. No thin film is formed on the substrate 9 in the co-closed state. At this time, the thickness of the thin film formed on the substrate 9 is measured by a crystal oscillator type film thickness monitor 3, and the signal from the quartz crystal oscillator type film thickness monitor 3 is supplied to the power source of the electron beam heating type evaporation source 6. Feedback is used to control the deposition rate of the deposition raw material. Further, instead of the crystal resonator type film thickness monitor 3, an optical film thickness monitor that is commonly used when forming a dielectric multilayer optical film may be used. Further, when forming a film of a material such as TiO ₂ or ZrO ₂ , it is common to deposit it in an O ₂ gas atmosphere, and the O ₂ gas is introduced from the reaction gas introduction port 12 at this time.

[Example 1] Using the thin film forming apparatus according to the present invention described above
A TiO ₂ monolayer film was formed. BK7 glass was used for the substrate, and TiO ₃ was introduced by introducing O ₂ gas to 5 × 10 ^-4 torr.
was deposited as a raw material. In addition, the substrate temperature during vapor deposition
40℃, 100℃, 150℃, 200℃, 250℃, 300℃, ultraviolet intensity on the substrate surface 0mW/cm ² , 0.5mW/cm ² ,
1mW/cm ² , 1.5mW/cm ² , 2mW/cm ² , 2.5mW/
cm ² and 3 mW/cm ² , and when the ultraviolet intensity on the substrate surface became 1 mW/cm ² or more for each substrate temperature, TiO ₂ formed
It was found that the adhesive force of the film increased rapidly.
The adhesion strength of the TiO ₂ film produced under the conditions of UV intensity 0 mW and substrate heating temperature 300°C is the same as that of the TiO ₂ film produced under the conditions of UV intensity 1 mW and substrate heating temperature 150°C, and the UV intensity is 1 mW/cm. It was found that the adhesion force of TiO ₂ films formed under conditions of ² or higher was higher than that. The adhesion of the TiO ₂ film was evaluated by the peeling method and the scratching method.

[Example 2] By heating MgF ₂ and ZnS as raw materials by electron beam heating and alternately opening and closing the shutter 4, 50 layers of an MgF ₂ film with a thickness of approximately 20 Å and a ZnS film with a thickness of approximately 16 Å are alternately formed. was formed and its electron diffraction was investigated. The substrate is a <100> plane of MgO single crystal, the vacuum layer is 1 to 2 x 10 ^-6 torr, the substrate heating temperature is 200℃, and the ultraviolet intensity on the substrate surface is
0mW/cm ² , 0.5mW/cm ² , 1mW/cm ² , 1.5mW/
cm ² , 2mW/cm ² , 2.5mW/cm ² , and 3mW/cm ² . As a result, the UV intensity on the substrate surface increases.
The MgF ₂ and ZnS alternating multilayer film produced under conditions of 0.5 mW/cm ² or less becomes a polycrystalline film containing many amorphous parts, and the ultraviolet intensity on the substrate surface is 1 mW/cm ² .
The MgF ₂ and ZnS alternating multilayer film produced under the condition of 1.5 mW/cm ² becomes a polycrystalline film, and the ultraviolet intensity on the substrate surface decreases.
It was found that an alternating multilayer film of MgF ₂ and ZnS produced under conditions of 2 mW/cm ² or more becomes a single crystal film, that is, a superlattice single crystal film. In this way, the alternating multilayer film of MgF ₂ and ZnS irradiated with UV rays so that the UV intensity on the substrate surface is 2 mW/cm ² or more is produced at a substrate temperature of 200 mW/cm 2 or more.
It was found that a superlattice single crystal film can be formed at a low temperature of ℃. These results have also been obtained for semiconductor materials such as alternating multilayer films of CdS and InSb. The substrate temperature at this time was 300°C.

[Effect of idea]

As described above, the thin film forming apparatus according to the present invention includes at least two electron beam heating evaporation sources, a shutter control mechanism that can independently cut off or release the raw material vapor from the evaporation sources, and a substrate temperature of 300°C or higher. By placing the substrate heating mechanism that can heat the substrate, the ultraviolet lamp that can produce a light intensity of 1 mW/cm ² or more on the substrate surface, and the reactive gas inlet in a vacuum chamber that can be evacuated to 10 ^-3 torr or less, it is possible to achieve strong adhesion. This makes it possible to fabricate dielectric multilayer optical films at low temperatures and also to synthesize new thin film materials called superlattice single crystals, increasing the reliability of dielectric multilayer optical components and enabling new industrial applications. It provides a material synthesis method and has a great effect on the optoelectronic industry. It also has the effect of increasing the adhesion of the film in a cheaper and safer way than conventional methods.

[Brief explanation of the drawing]

The figure is a configuration diagram of a thin film forming apparatus according to the present invention. 1... Vacuum chamber, 2... Substrate heating heater, 3...
...Crystal resonator type film thickness monitor, 4...Shutter, 5...Exhaust port, 6...Electron beam heating type evaporation source, 7...Vacuum gauge, 8...Substrate holder, 9
... Substrate, 10 ... Thermocouple, 11 ... Ultraviolet lamp, 12 ... Reaction gas inlet.

Claims (1)

[Claims for Utility Model Registration] A thin film forming apparatus having a vacuum chamber that can be evacuated to at least 10 ^-3 torr or less, two or more evaporation sources in the vacuum chamber, and each source vapor from the evaporation sources. A thin film forming apparatus characterized in that a shutter control means that can be independently shut off or released, a substrate heating means that heats the substrate, an ultraviolet generating means that irradiates the surface of the substrate, and a gas introduction port that introduces a reactive gas are arranged. .