JPH0456801A - Production of diffraction grating - Google Patents

Abstract

PURPOSE:To easily produce the glass diffraction grating having a desired shape, high accuracy and high strength by inscribing desired shapes on the surface of the glass by using a physical technique. CONSTITUTION:A mask of line and space patterns is formed on the surface of a plane glass substrate 22 and the diffraction grating shape is formed on the glass surface by dry etching. Then, the shape of the diffraction grating can be controlled by the thickness of the mask and the line width of the line and space patterns. The diffraction gratings of the same shape are thus obtd. with good reproducibility. The glass surface having the high strength and the good durability is easily and finely worked in this way and the diffraction grating having the desired shape is easily obtd.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention applies fine processing to a durable glass surface.
The present invention relates to a method for easily manufacturing a reliable and highly accurate diffraction grating.

Conventional technology Conventionally, as a method for producing high-precision diffraction gratings, a diamond tool is held directly onto a flat glass plate coated with a metal such as aluminum (AN) using a high-precision ruling engine. The method of forming grooves at equal intervals by attaching
As shown in 19B5.6.17゜ρ, 85, another resist is formed in a line-and-space pattern at equal intervals on the resist, and physically etched to process the resist into a sawtooth shape. How to do it and how to apply for it
2-331972, a method has been studied in which a photosensitive resin is formed into a diffraction grating shape by hologram exposure, and after development, a metal such as aluminum is deposited on the resin to create a reflective holographic diffraction grating. ing.

Problems to be Solved by the Invention However, with conventional methods, it takes a very long time to produce one diffraction grating, and furthermore, it is difficult to produce high-precision gratings in large quantities, and there are problems with reproducibility. there were. In addition, since all of the fabricated diffraction gratings had a diffraction grating shape carved into a soft material, there were also problems with durability.

In view of the above problems, an object of the present invention is to manufacture a highly durable diffraction grating made of glass by carving a desired shape into the surface of glass using a physical method.

Means for Solving the Problems In order to solve the above problems, in the present invention, a line-and-space pattern mask is formed on the surface of a flat glass substrate, and a diffraction grating shape is formed on the glass surface by dry etching. This made it possible to create a durable diffraction grating made of glass.

Furthermore, since the shape of the diffraction grating can be controlled by the thickness of the mask and the line width of the line-and-space pattern, it is possible to easily obtain diffraction gratings of the same shape with good reproducibility.

Effect of the Invention The present invention makes it possible to easily produce a high-precision, high-strength glass diffraction grating of a desired shape using the above-described method.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

After polishing the surface of the glass substrate using diamond abrasive grains, the surface of the glass substrate was coated with a positive resist to a thickness of 0.5 μm using a spin cord.

This resist has a wavelength of 441.6 as shown in Figure 1.
After separating the laser beam into two beams and interfering with each other, the photosensitive area is irradiated with a developer, and then baked at 120°C to form a diffraction grating shape as shown in Figure 2 on the glass surface. Formed.

In FIG. 1, 11 is a light source, 12 is a half mirror, and 13 is a light source.
14 is a reflecting plate, 14 is a pinhole, and 15 is a sample. Second
In the figure, 21 is a resist, and 22 is a glass substrate.

Next, a chromium (Cr) film with a thickness of 0.1 μm was formed on this glass substrate by a vapor deposition method. The cross-sectional shape of the glass substrate at this time is shown in FIG. In Figure 3, 3I
32 is a resist, 32 is a Cr thin film, and 33 is a glass substrate.

Thereafter, only the resist was dissolved using an organic solvent.

The cross-sectional shape at this time is shown in FIG. In Figure 4,
41 is a Cr thin film, and 42 is a glass substrate. As is clear from FIG. 4, a Cr mask with a line-and-space pattern having a line width of 0.5 μm and a pitch of 1.0 μm is formed on the glass substrate.

The glass substrate in the state shown in Fig. 4 was etched in the ECR (Electron Cyclotron Resonance) plasma ion shower etching device shown in Fig. 5 using centrifugal gas, CHF, and gas perpendicular to the ion source, and the cross-sectional shape of the testis was observed. As shown in Figure 6, the shape when the Cr mask is completely etched has a step difference of 1.0. pitch is 1.0 in um
It can be seen that a wavy diffraction grating of μm is formed.

In FIG. 5, 51 is an ion extraction electrode, 52 is an ion source, 53 is a shutter, 54 is a substrate holder, and 55
is the exhaust system. In FIG. 6, 61 is a glass substrate.

Further, when the glass substrate was set at an angle of 45 degrees with respect to the ion source, a surfing wave-shaped diffraction grating as shown in FIG. 7 was obtained. In FIG. 7, 71 is a glass substrate.

Further, FIGS. 8 to 10 show the diffraction grating shapes that can be formed on the surface of the glass substrate when the line width of the Cr mask with the same pinch line-and-space pattern is changed.

In the diffraction grating shown in FIG. 8, the line width ratio of lines and spaces is 4:1.

The ratio in FIG. 9 is 1:1, and the ratio in FIG. 10 is 1:4. In FIGS. 8, 9, and 10, 81.91101 is a glass substrate. In this way, diffraction gratings of various shapes can be produced by changing the ratio of the line widths of lines and spaces.

After a diffraction grating shape was directly carved on the surface of the glass substrate in this way, a thin gold (Au) film was formed as a reflective film on the surface by vapor deposition. Table 1 shows the diffraction efficiency of each diffraction grating at this time.

(Left below) Table 1 Diffraction efficiency of each diffraction grating From Table 1, it can be seen that the diffraction efficiency differs depending on the shape. Therefore, it can be seen that it is possible to change the diffraction efficiency by changing the ratio of the line widths of the lines and spaces of the mask.

It can also be seen that the diffraction efficiency can be further improved by changing the angle of the substrate.

As described above, it can be seen that according to the present invention, a glass diffraction grating having a desired shape can be easily formed.

In this embodiment, a Dr thin film was used as the mask material, but it goes without saying that any material can be used as the mask material as long as it can be selectively etched with glass.

Furthermore, depending on the mask material and etching conditions used,
The shape of the diffraction grating that can be formed can also be varied.

Effects of the Invention By the method of the present invention, it has become possible to easily perform fine processing on a very strong and durable glass surface, and it has become possible to easily obtain a diffraction grating of a desired shape.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a three-beam interference exposure apparatus in an embodiment,
Figures 2, 3, and 4 are cross-sectional views of fabricated samples at each stage of the process in the examples, Figure 5 is a schematic diagram of the etching apparatus used in the examples, Figures 6, 7, Figures 8 and 9
10 are cross-sectional views of a glass diffraction grating manufactured by the method of the present invention. 11...Light source, 12...Half mirror
113...Reflector, 14...Pinhole, 15...t&T4゜Name of agent: Patent attorney Shigetaka Awano (1 person) 11-1-1) Hara No. 4 Figure\42! 2v4 Figure 5 m-22 Figure 3 9A Figure Figure Figure 1゜Figure

Claims (2)

[Claims] (1) A method for producing a diffraction grating, which comprises forming a line-and-space pattern mask on the surface of a flat glass substrate and forming a diffraction grating shape on the glass surface by dry etching. (2) The method for producing a diffraction grating according to claim (1), wherein the shape of the diffraction grating is controlled by the thickness of the mask and the line width of the line-and-space pattern.