JPH05164908A - Production of prototype of diffusion plate - Google Patents

Abstract

PURPOSE:To obtain a process for production of the prototype of a diffusion plate which can rapidly produce the prototype of the diffusion plate with high accuracy by simple production process. CONSTITUTION:A metallic film pattern 26 is obtd. by utilizing a 1st stage for depositing a metallic film 22 by evaporation on the surface of a metallic substrate 1, a 2nd stage for forming the metallic film pattern 24 having two levels of varying heights by spin coating the surface of the metallic film 22 with a photoresist 23, then subjecting the photoresist to exposing and developing via a mask then to an etching treatment and a 3rd stage for forming the metallic film pattern 26 having three levels of varying heights by spin coating the surface of the metallic film pattern 24 with a photoresist 25, then subjecting the photoresist to the exposing and developing via the mask then to the etching treatment. The diffusion plate is produced by using the above-mentioned metallic film pattern as the prototype.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a prototype of a phase type diffuser plate, and when used as a focusing plate for forming a finder image in a photographic camera or the like, it has a predetermined diffuser characteristic and a good finder The present invention relates to a method for manufacturing a prototype of a phase type diffusion plate that allows image observation.

[0002]

2. Description of the Related Art Conventionally, a plurality of fine patterns of a predetermined shape having a constant height are formed on an optically transparent substrate surface, and a light beam passing through the fine patterns is given a phase difference with respect to other light beams. Then, various phase type diffusion plates having a predetermined diffusion characteristic have been proposed.

Among them, a phase type diffusion plate having a plurality of phase differences as a whole with a phase difference of 0 and a predetermined phase difference θ with respect to an incident light beam is disclosed in, for example, Japanese Patent Application Laid-Open No. 55-70827 and Japanese Patent Application Laid-Open No. 1-302331. It is proposed in Japanese Patent Publication.

As a method of manufacturing a prototype for manufacturing these diffuser plates, for example, in Japanese Patent Laid-Open No. 57-13403, laser light is used to perform exposure, development bleaching and the like to obtain a smooth sine curve. Roughness or speckle pattern-shaped irregularities are formed and transferred by plating in an electroforming process to manufacture a prototype.

In Japanese Patent Laid-Open No. 61-120128, a pyramidal pattern is formed by mechanical cutting and transferred by plating to manufacture a prototype.

Further, in Japanese Patent Laid-Open No. 1-277222, a prototype is manufactured by forming a smooth pattern on a photoresist and transferring it by plating.

[0007]

In the conventional master mold manufacturing method, a silver halide photosensitive material was used for the original master in order to form smooth irregularities. Therefore, if the original master is directly used as a master, the silver salt photosensitive material is fragile, and the durability as a master is not sufficient.

Further, in order to make the original master by cutting the pyramidal pattern, a soft material that can be cut must be used. Therefore, the durability is not sufficient to directly make the original master. It was

For this reason, the conventional master for manufacturing the diffuser plate is manufactured by once manufacturing the original master by some method and transferring it by a plating process such as an electroforming process. It was

As described above, conventionally, a master is manufactured from a master using a predetermined process, and a lot of time is required to manufacture the master of the diffuser plate because a lot of time is required for the finishing process. There was a problem of this.

The present invention is a diffuser plate that can be manufactured quickly and highly accurately by a simple manufacturing process by using a process of appropriately setting a prototype for manufacturing a diffuser plate and using a metal film of a suitable material. The purpose of the present invention is to provide a method for producing a prototype.

[0012]

The method for producing a prototype of a diffusion plate of the present invention comprises a first step of depositing a metal film on the surface of a metal substrate, spin coating of a photoresist on the surface of the metal film, and then exposure. A second step of developing, forming a predetermined resist pattern, etching the metal film, and then removing the photoresist to form a metal film pattern having two different height levels, and then the metal film After spin-coating a photoresist on the pattern surface, exposure and development are performed to form a predetermined resist pattern, the metal film is etched, and then the photoresist is removed to obtain three different height levels as a whole. It is characterized in that the diffusion plate is manufactured by using the metal film pattern obtained by utilizing the third step of forming the metal film pattern which is provided as a prototype.

Particularly in the present invention, the metal film is made of titanium nitride (TIN), the etching process is a reactive ion beam etching method using C ₂ F ₆ gas, and the metal substrate is 6 mm to 15 mm. The metal film has a thickness of 1 μm to 3 μm, the hardness HD of the metal film is 650 or less, and the thickness of the photoresist is 0.8 μm to 5 μm. The etching in the second step is characterized by a thickness of 0.3 μm to 0.8 μm.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part showing each step of a method for manufacturing a prototype of a diffusion plate of the present invention.

In FIG. 1A, reference numeral 21 is a metal substrate. The metal substrate 21 has relatively few material defects, is easy to secure good surface accuracy, and is easy to process HPM38SS
Is used, and the thickness is about 6 mm to 15 mm.
The surface precision of one side is finished within the range of 5 to 15 Newtons.

This surface accuracy is the surface accuracy required when a metal (titanium nitride, TIN) is formed on the surface, and after resist coating, the chromium mask and the resist are exposed by the hard contact method. Generally, chrome masks tend to have a negative (concave) surface accuracy.

If the substrate is made of glass or a compound of silicon oxide and silicon (SiO ₂ + Si), etc., and has a small thickness, the substrate is made to some extent in correspondence with the chrome mask even if a hard contact is made, and an adhesion with good resolution is obtained. Be done.

However, in the present invention, since the original master is directly used as a prototype, the substrate is metal and the thickness is 6 mm to 15 m.
m. For this reason, the master cannot be firmly fixed during molding. Such a thick metal substrate does not correspond to a chrome mask.

Therefore, in this embodiment, the metal substrate 21 is not flat but has a surface accuracy of about 5 to 15 Newtons and a convex shape, thereby improving the adhesion to the chrome mask and the resolution. Has good adhesion.

In FIG. 1B, the metal substrate 21 is washed and a metal film (TIN) 22 is formed on the surface thereof by the ion plating method (first step).

At this time, the thickness of the TIN film 22 is 1 μm to 3 μm.
It is set to be μm. This is because when the diffusion plate is used as the focusing screen, the required depth of the prototype is 0.6 μm to 1.6 μm.
μm. Therefore, the metal film (TIN film) 22 is made to have a depth approximately twice the depth at this time to ensure sufficient durability of the master when molding, so that the TIN film 22 does not come off.

A TIN film having a thickness of 3 μm or more is not preferable because TIN defects are likely to occur.

In addition to this, when it is used as a focusing screen of a camera, it is necessary to form marks for autofocus and marks for photometry in the mold of the focusing screen. Therefore, if the TIN film is too hard, it becomes difficult to process these marks.

Therefore, in this embodiment, the hardness of the metal film 22 is H.
A value of 650 or less is used.

In FIG. 1C, after the TIN film is formed, it is washed and the photoresist 23 is spin-coated. At this time, the most common resist is dropped and then rotated in one step at low speed and in two steps at high speed. If the resist is not installation-free (SF), the installation (radial stripe pattern) is the resist surface. This stripe pattern remains undesirably when etched.

Therefore, in this embodiment, when spin coating is performed without using a installation-free (SF) resist, the photoresist is dropped while being rotated at a constant speed, and thereafter, the photoresist is continuously rotated at a constant speed to perform spin coating. This removes the installation.

Specifically, an OFPR2 (25 cp) (Tokyo Ohka) resist is used, the resist is rotated at 1000 rpm for 2 seconds, and the resist is dropped for 1 second while rotating. And after that, it continued to rotate at 1000 rpm for a total of 30
Rotate for seconds. As a result, a resist film without radial stripes having a film thickness of 2.0 to 3.0 μm is obtained.

Then, in FIG. 1D, UV light (ultraviolet light)
Then, the chrome mask and the resist substrate are brought into close contact with each other, exposed, developed and post-baked.

In FIG. 1 (E), C ₂ F ₆ gas, which has high safety and resists etching of the resist, is used, and the reactive ion beam etching method (RIBE method) is used to obtain 0.3.
Etching is performed in the range of μm to 0.8 μm. After etching,
The unnecessary resist 23 is removed. Thus, the metal film pattern 24 having two different height levels is formed (second step).

In FIG. 1F, the substrate is washed.
1 (G) to 1 (I), substantially the same repetitive processing as in FIGS. 1 (C) to 1 (E) is performed.

That is, in FIG. 1G, the metal film pattern 24 is formed.
A resist 25 is spin-coated on the surface. Figure 1
In (H), the chrome pattern and the resist substrate are exposed to each other by contact, and then developed and post-baked. In FIG. 1 (I), RI
Etching of 0.3 μm to 0.8 μm is performed by the BE method.

After etching is completed, unnecessary resist 25
, Which results in three different heights as shown in FIG.
A metal film pattern 26 having two levels A, B and C is formed (third step).

In the present embodiment, a metal film pattern such as unevenness, pyramids, and cones having three levels of different heights is formed on a TIN film having good durability by using the above-mentioned steps to manufacture a diffusion plate. We are manufacturing the prototype.

In this embodiment, after resist coating,
When etching by the RIBE method, the etching ratio between the resist and the TIN film is 1: 2 to 1: 6 in terms of selectivity.

Here, as shown in FIG. 2, when the diffuser plate is configured to have three levels A, B, and C having different heights, the depth from A level to B level or the level from B level to C is obtained.
Unless the level depth is in the range of 0.3 μm to 0.8 μm, it becomes difficult to obtain good optical performance when used as a focusing screen of a camera.

Therefore, in this embodiment, RIE is performed once and twice.
The etching amount by the B method is also set to 0.3 μm to 0.8 μm.

That is, the TIN film has a thickness of 0.3 μm to 0.8 μm.
At this time, since the selection ratio with the resist is 1: 2 to 1: 6, the resist film needs to be 0.6 μm to 4.8 μm.
However, if the value is in this range, the resist may be completely lost.

Therefore, in order to leave at least 0.2 μm of resist, in this embodiment, the resist film thickness is 0.8 μm
It is set to 5 μm.

In the above embodiments, the case where the present invention is applied to the method for producing a prototype of a diffusion plate has been described. However, the present invention is applicable to the production of low pass filters, high pass filters, band pass filters, soft focus filters, etc. Can be similarly applied.

[0040]

According to the present invention, as described above, a process for appropriately setting a prototype for manufacturing a diffuser plate and a metal film made of an appropriate material can be used for a quick and highly accurate process by a simple manufacturing process. It is possible to achieve a method for manufacturing a prototype of a diffuser plate that can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a diffusion plate manufactured by the prototype of the present invention.

[Explanation of symbols]

 1 Metal Substrate 22 Metal Film (TIN Film) 23,25 Resist 24,26 Metal Pattern

Claims (3)

[Claims] 1. A first step of depositing a metal film on a surface of a metal substrate, and a spin coating of a photoresist on the surface of the metal film, followed by exposure and development to form a predetermined resist pattern,
After etching the metal film, removing the photoresist to form a metal film pattern having two different height levels, and then spin-coating the photoresist on the metal film pattern surface. After exposing and developing to form a predetermined resist pattern and etching the metal film, the photoresist is removed to form a total of 3
And a third step of forming a metal film pattern having three different height levels, and a diffuser plate is manufactured using the metal film pattern obtained as a prototype. Method. 2. The prototype of the diffusion plate according to claim 1, wherein the metal film is made of titanium nitride (TIN), and the etching process is a reactive ion beam etching method using C ₂ F ₆ gas. Production method. 3. The metal substrate has a thickness of 6 mm to 15 mm, the metal film has a thickness of 1 μm to 3 μm, and the hardness HD of the metal film is 650 or less. The thickness is 0.8 μm to 5 μm, and the etching in the second step is 0.3 μm to 0.8 μm.
The method of manufacturing a prototype of a diffusion plate according to claim 1, wherein the prototype has a thickness of μm.