JPH07239407A - Replica diffraction grating - Google Patents

Abstract

PURPOSE:To obtain a long-life replica diffraction grating by forming a chemically inactive protective layer on the surface of a metal thin film of the replica diffraction grating which is produced by reverse adhesion. CONSTITUTION:This replica diffraction grating is obtd. by forming an aluminum thin film 4 on the grating surface of a master diffraction grating, pressing a replica substrate 6 with an adhesive 5 to the aluminum thin film 4, and then peeling the replica to reversely adhere the aluminum thin film 4 on the replica substrate 6. Silicone grease 7 is vapor deposited as a chemically inactive protective layer on the surface of the aluminum thin film 4. By this method, the obtd. replica is made chemically inactive compared to a conventional grating with a metal thin film exposed on the surface. Thereby, oxidation, carbonization, solidification or the like is hardly caused and the obtd. replica has higher durability without corrosion with <=30% acid or alkali. Further, heat resistance, resistance against cold weather, and resistance against radiation are increased. Water repellency is given to the replica to increase resistance against permeation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a replica diffraction grating used for spectroscopy in ultrahigh vacuum.

[0002]

2. Description of the Related Art A method of mass-producing diffraction gratings (replica diffraction gratings) by making many replicas from a master diffraction grating has been conventionally performed, and a typical method thereof is as follows.

That is, first, a master diffraction grating is manufactured by depositing a metal thin film such as aluminum on a glass substrate and forming a grating groove in the film. Using this master as a master, a thin oil film is formed on the lattice surface as a release agent, an aluminum thin film is formed on it by vacuum deposition, and then a glass substrate is coated with an adhesive (heat resistant resin) on this aluminum thin film. The aluminum thin film is moved to the glass substrate side by peeling the glass substrate from the mother die after the adhesive is cured and the adhesive is cured, and a replica diffraction grating is obtained.

[0004]

However, since the replica diffraction grating manufactured by the conventional method has a shape in which the metal thin film such as aluminum is exposed, the metal surface is oxidized, or the acid or alkali is used. It was a problem because it could easily chemically react with etc. In addition, on the surface of aluminum or the like, when used under high temperature conditions, thermal change occurs such that crystal grains are generated in the aluminum film, and the performance as a diffraction grating is significantly deteriorated.

Further, the diffraction grating used for a high power laser or the like needs to be resistant to temperature rise and less susceptible to radiation damage, but there is a problem with the surface of aluminum or the like. Therefore, an object of the present invention is to provide a long-life replica diffraction grating that does not have the above problems.

[0006]

In order to solve the above problems, the present invention forms a metal thin film on the grating surface of a master diffraction grating, press-contacts the metal thin film and a replica substrate with an adhesive, and then peels them off. In a replica diffraction grating obtained by reversely adhering the metal thin film to a replica substrate, a chemically inert protective layer is provided on the surface of the reversely adhered metal thin film.

Here, the master diffraction grating is glass,
An inorganic material such as SiO ₂ is directly engraved on the substrate, or a metal thin film such as aluminum is vapor-deposited on the substrate and engraved on it. The engraved area becomes the lattice plane. . The engraved line may be a machine engraved line by a diffraction grating engraving device or an engraved line by ion beam etching.

Examples of the metal thin film include thin films of aluminum, gold, platinum and the like, and these thin films are formed on the grating surface of the master diffraction grating by, for example, vacuum deposition. After forming the metal thin film, a release agent is applied to the grating surface of the master diffraction grating. As the release agent, for example, silicone grease or the like can be used.

It is preferable that the replica substrate is made of a material having a low expansion coefficient in order to suppress the change in the groove spacing due to the temperature rise. Expanded crystal glass can be mentioned. However, the material is not limited to these, and when the diffraction grating is used in a region where the temperature rise is small, BK7, BSC2, Pyrex glass, soda glass, etc. can also be used.

A thermosetting resin such as urea resin, melamine resin, phenol resin, or epoxy resin can be used as an adhesive agent for adhering the metal thin film and the replica substrate, but for the purpose of reducing the influence of thermal strain. A visible light curable resin can also be used. Examples of the visible light curable resin include BENEFIX VL (manufactured by Adell Co., Ltd.), but are not limited thereto.

The chemically inert protective layer corresponds to, for example, a thin film of silicon grease formed on the surface of a metal thin film, but is not limited thereto. The thin film of silicon grease is formed by vacuum vapor deposition, for example. Further, when silicon grease is used as a release agent on the grating surface of the master diffraction grating, the silicon grease remaining during replica production can be effectively used.

[0012]

According to the present invention, by forming a chemically inactive protective layer on the surface of a metal thin film, oxidation and carbonization are extremely unlikely to occur, and resistance to acid and alkali solutions is increased. Further, heat resistance, cold resistance, and radiation resistance are increased, water repellency is imparted, and erosion resistance is also increased.

Further, it is possible to prevent the generation of crystal grains in the metal film on the surface. In addition, by using a heat-resistant adhesive for the adhesive layer of the replica diffraction grating, it has become possible to manufacture a bakable replica diffraction grating. Furthermore, by providing the protective layer, dust and dirt on the surface can be easily removed with a blower or the like.

[0014]

EXAMPLE A process for producing a replica diffraction grating according to the present invention will be described with reference to the drawings.

First, the flat glass substrate 1 (quartz glass: 6)
0mm x 60mm x 11.3mm) photoresist O
FPR5000 (manufactured by Tokyo Ohka Co., Ltd.) is coated to a thickness of 0.4 μm, and the holographic exposure method (laser wavelength 4
41.6 nm) to form lattice grooves (1200 / mm). After that, a groove cross-section with a blaze angle of 4 degrees is formed into a sawtooth shape by ion beam etching, and an aluminum thin film (thickness: 0.2 μm) 2 is vacuum-deposited on the groove to manufacture a master diffraction grating. This state is shown in Figure 1.
It is (a).

A thin oil film 3 (thickness: about 1 nm) is formed on the master diffraction grating using silicon glycose as a release agent, and an aluminum thin film (thickness: 0.2 μm) 4 is vacuum-deposited on the thin oil film 3. This state is shown in FIG.

Next, a replica substrate (quartz glass; 60 mm)
X 60 mm x 11.3 mm) 6 is prepared, the surface thereof is washed with Freon or the like, and then an adhesive (heat resistant epoxy resin) 5 is applied. Then, the replica substrate 6 and the above-mentioned master diffraction grating are bonded. This state is shown in FIG.
It is (d).

After the adhesive is hardened, the replica substrate 6 is peeled off with the release agent 3 as a boundary, and the aluminum thin film 4 is transferred to the replica substrate 6 to form a replica diffraction grating. The state at this time is shown in FIG.

Then, silicon grease 7 is vacuum-deposited on the surface of the aluminum thin film 4. The state at this time is shown in Figure 1.
(E). This was heated to 300 ° C. in a baking oven, surface accuracy was measured with a laser interferometer, and diffraction efficiency and scattered light intensity were examined with an efficiency measuring device. As a result, no change was observed.

Furthermore, since the silicone grease is colorless and transparent and has good transparency, it can be used as a transmissive element by depositing a silicone grease layer without forming a metal layer on the surface.

[0021]

According to the present invention, compared with the conventional metal thin film exposed on the surface, it becomes chemically inactive and is oxidized,
Carbonization, solidification, evaporation, etc. are extremely unlikely to occur, and 30%
It is not corroded by the following acids and alkalis.

Further, in the conventional product, when heated to about 150 ° C., a thermal change occurs in which crystal grains are generated in the metal thin film on the surface, and the performance as a diffraction grating is remarkably deteriorated. The present invention prevents this. be able to.

Furthermore, by using a heat-resistant adhesive for the adhesive layer, it becomes possible to manufacture a bakeable replica diffraction grating that can withstand temperatures up to 300.degree. In addition, this has the surface having water repellency and has the effect of increasing the weather resistance, and it is easy to remove dust and dirt attached to the surface with a blower or the like.

Moreover, a spectroscopic study using a high-power laser or SR as a light source, which has been rapidly developing in recent years, makes it possible to manufacture a diffraction grating that can sufficiently withstand baking. Also,
By forming the silicon grease layer, resistance to radiation is also increased.

[Brief description of drawings]

FIG. 1 is a process drawing of manufacturing a replica diffraction grating of the present invention.

[Explanation of symbols]

 1: Glass substrate 2: Aluminum thin film 3: Release agent 4: Aluminum thin film 5: Adhesive 6: Replica substrate 7: Silicon grease

Claims (1)

[Claims] 1. A replica obtained by forming a metal thin film on a grating surface of a master diffraction grating, press-contacting the metal thin film and a replica substrate with an adhesive, and then peeling the metal thin film and inverting and adhering the metal thin film to the replica substrate. In the diffraction grating, a replica diffraction grating, characterized in that a chemically inactive protective layer is provided on the surface of the metal thin film that has been reverse-bonded.