JPH06201908A - Production of stamper for diffraction grating - Google Patents

Abstract

PURPOSE:To improve the transferability of a diffraction grating shape and the release property of a master disk from molded goods. CONSTITUTION:Diffraction grating patterns 2 are formed by using a resist on a glass substrate 1. A conductive thin film 3 consisting of a composite film made by uniformly dispersing a fluororesin and Cr is formed by a two-element vapor deposition method on the diffraction grating patterns 2. An Ni electrocasting layer 4 is thereafter formed on the conductive thin film 3 by an electrocasting method and a glass substrate 1 is released with the conductive thin film 3 as a boundary, to obtain the stamper 5. The fluororesin incorporated in the conductive thin film 3 has an excellent release property from the glass substrate 1 and the molded goods 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a stamper for a diffraction grating.

[0002]

2. Description of the Related Art As a conventional method of manufacturing a stamper for replicating a diffraction grating, a resist is coated on a glass substrate, UV irradiation is performed using a mask, development is performed, and heat treatment is applied to form a pattern. . Then, after forming a conductive film by a dry process or a wet process, Ni
Electroforming is performed to reverse the pattern. It is an important point to accurately transfer a fine shape in such a process,
High adhesion is required in the inversion process. However, the high adhesion has a problem that it causes a resist residue or glass substrate destruction at the time of demolding.

To solve this problem, Japanese Patent Laid-Open No. 30382/1990
A manufacturing method as disclosed in Japanese Patent No. 0 is shown. In this manufacturing method, after a pattern is formed on a glass substrate, a Ni film having a thickness of 500 Å or more is formed by a sputtering method or a vacuum evaporation method.
To form a first metal thin film. The first metal thin film is subjected to surface oxidation treatment with potassium dichromate or high-concentration ozone to form a release promoting film. A second metal thin film is formed on the surface of the release promoting film by the same method as the first metal thin film, and then a Ni layer is formed by electroforming. And
After transfer, the stamper is obtained by demolding at the boundary of the release promoting film.

[0004]

However, it is not possible to obtain sufficient transferability and releasability with the method disclosed in JP-A-2-303820. This is because the stamper transfers the first metal thin film having the release promoting film formed on the pattern because it is released from the release promoting film as a boundary, and the pattern itself is transferred. Absent.
Therefore, it is not possible to sufficiently perform accurate transfer of a fine shape. Accurate transfer is particularly important in the diffraction grating, because the groove depth, the ratio of the upper and lower portions of the rectangle, and the reproducibility of the edges greatly affect the diffraction efficiency.

Further, there is a problem that the first metal thin film is peeled off to the stamper side at the time of demolding. In the known technique, there is a process in which the conductive film formed on the glass substrate and the glass substrate are used for demolding, and the mold releasability is known. However, in the prior art described in the publication, in the demolding step of holding the substrate side and the electroformed side independently and instantaneously peeling by mechanical pulling, the adhesion between the glass substrate and the first metal thin film is demolded. It peels off because it cannot withstand the forces that sometimes occur. The cause is that there are two interfaces, that is, the glass substrate and the first metal thin film, and the release promoting film and the second metal thin film on the first metal thin film, and the upper part of the rectangle. Since the force at the time of demolding that is applied to the lower and side surfaces is dispersed, and a part where a demolding force greater than the adhesive force acts on the interface between the glass substrate and the first metal thin film, the glass substrate and the first metal thin film are generated. The peeling of the thin film occurs. Therefore, good demolding cannot be obtained at the time of demolding.

Further, there is a problem in that a good mold release from the resin cannot be obtained in the molding process using the obtained stamper. Originally, since the diffraction grating has a rectangular shape, there are quite a lot of parts having a slope of 0 ° which causes deterioration of the mold releasing property. Therefore, it becomes difficult to take out the molded product, and there arises a problem that the resin is stuck to the rectangular portion of the stamper and cannot be removed. In order to solve this problem, in the prior art, the mold release promoting film is formed on the side of the first metal thin film, so that the stamper after the mold releasing has the second
Only the metal thin film is attached, and there is no release promoting film on the stamper surface. Therefore, at the time of molding, the problem of the resin sticking to the second metal thin film still occurs. Therefore, in the conventional technique, good mold release from the resin cannot be obtained in the molding process.

The present invention has been made in view of the above-mentioned problems of the prior art, and is excellent in transferability of a fine diffraction grating shape, excellent in releasability from a master, and releasable from resin during molding. It is an object of the present invention to provide a method of manufacturing a diffraction grating stamper that is excellent in manufacturing.

[0008]

In order to achieve the above object, the present invention provides a method for forming an electroconductive film by forming a diffraction grating pattern on a glass substrate using a resist and then applying the electroforming method. In the manufacturing method of obtaining a stamper by forming a Ni electroformed layer by removing the Ni electroformed layer, the conductive film is composed of a composite film of metal and fluororesin. Then, the conductive film may be manufactured by a physical film forming method. Further, the conductive film may be a gradient composition conductive film in which the composition of the fluororesin decreases from the glass substrate side toward the Ni electroformed side.

[0009]

Next, the operation of the method of manufacturing a stamp for a diffraction grating of the present invention in the above steps will be described in detail. A desired diffraction grating pattern is formed on the glass substrate by photolithography using a resist. In order to obtain good diffraction efficiency, it depends on how accurately this diffraction grating pattern is transferred to the stamper in the subsequent steps. After forming an accurate pattern on the glass substrate, a conductive film for electroforming is formed.

A dry process and a wet process can be considered for forming the conductive film. However, in a wet process such as electroless plating, it is difficult to control the plating bath so that it does not deteriorate as the protrusion progresses. It cannot be formed. For this reason, it becomes difficult to accurately maintain the fine pattern due to the internal stress and the difference in linear expansion after demolding.

Therefore, for the formation of the conductive film, film formation by a dry process capable of controlling a uniform and uniform thickness is selected. The dry process includes a physical film forming method and a chemical film forming method. Generally, a physical film forming method is used.
Specifically, it is a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like.

There are two types of film-forming materials for the electroconductive thin film, and one is a metal having electroconductivity, and Ni, Cr and the like are considered. Another film-forming material is a fluororesin, which has releasability. The characteristics of the fluororesin are that it has a strong bond energy between fluorine and carbon and a small polarizability, so that the surface energy is greatly reduced, so that it is rich in adhesiveness and excellent in releasability. The above two kinds of materials are simultaneously formed on a substrate by using a dry process. The formed conductive thin film is a composite film in which the fluororesin is uniformly dispersed in the metal film. After forming the conductive thin film, Ni is formed by electroforming.
An electroformed layer is formed, and the transfer of the master is completed.

The adhesion between the electroconductive thin film whose main composition material is metal and the Ni electroformed layer is good. Therefore, demolding is performed between the glass substrate and the conductive thin film. The excellent releasability, which is a characteristic of the fluororesin, acts on the demolding to suppress the phenomenon that the conductive film is peeled off to the glass substrate side, thereby enabling the good demolding. Further, since the conductive thin film directly transfers the stamper itself after the mold is removed, it has a sufficient effect on the problem of accurate transfer that greatly affects the diffraction efficiency.

In the above structure, since the composite film in which the fluororesin is uniformly dispersed forms the stamper surface,
The molding resin is in direct contact with the composite film in which the fluororesin is uniformly dispersed. The fluororesin has excellent releasability with respect to the molding resin. Therefore, it is possible to suppress the problem of the molding resin sticking to the stamper at the time of molding and perform good mold release.

Further, when the composition of the fluororesin is formed so as to form a gradient composition conductive film which decreases from the glass substrate side to the electroformed layer side, it has the following characteristics. First,
Since the composition ratio of the fluororesin in the conductive thin film that is in direct contact with the glass substrate is high, it is excellent in demolding at the time of demolding. This is nothing but an improvement in releasability in proportion to the fluorine atom density. Further, since the composition ratio of the fluororesin in the conductive thin film that is in direct contact with the electroformed layer is low, the adhesion between the conductive thin film and the electroformed layer is excellent. This is because the surface energy of the conductive thin film is high due to the low fluorine atom density, and the adhesion with the electroformed layer is improved.
Therefore, by forming the gradient composition conductive film, the releasability from the glass substrate and the adhesion to the electroformed layer are further improved.

[0016]

[Embodiment 1] Embodiment 1 of the present invention will be described based on the steps of FIG. First, after applying a resist to the glass substrate 1,
The resist pattern is formed by UV irradiation, exposure, development, and heat treatment. In this embodiment, the diffraction grating pattern has a rectangular shape. In the shape of this rectangular pattern, there are parameters such as the groove depth, the ratio of the upper and lower parts of the rectangle, and the angle of the edge, and it is necessary that each be an optimum shape in order to obtain good diffraction efficiency. In order to increase the ± first-order diffraction intensity, it is necessary that the ratio of the upper and lower parts of the rectangle is 1: 1 and the side faces are vertically raised, and the edges of the upper and lower parts of the rectangle are 90 degrees.

Further, after the glass substrate 1 is etched by RIE, an oxygen plasma irradiation treatment is applied to the glass substrate 1 shown in FIG.
The glass substrate 1 having the diffraction grating pattern 2 shown in FIG. The pitch of the diffraction grating pattern 2 is 3 μm,
The groove depth is about 0.4 μm. This is a diffraction grating used for semiconductor laser light having a wavelength of 780 nm.

After the glass substrate 1 is set in a vacuum vapor deposition apparatus, Cr is vaporized by an electron beam heating vapor deposition method and, at the same time, a fluororesin is vaporized by a resistance heating method. To form (Fig. 1
(See (B)). The composition ratio is approximately Cr: fluororesin =
At 4: 6, the film pressure is 1000Å.

After that, activation is carried out with an aqueous solution of sulfamic acid of about 1 mol / l, the surface is immersed in an electrolytic solution containing nickel sulfamate as a main component so as to face the nickel anode, and direct current is applied while stirring to perform electroforming. And then
An electroformed Ni layer 4 is formed as shown in FIG. After that, the glass substrate 1 is demolded, and then machined into a desired shape to obtain a stamper 5 (see FIG. 1D). Then, the stamper 5 is incorporated into a mold as a nest, the mold is attached to an injection molding machine, and then molding is performed using PMMA resin to obtain a molded product 6 in which a diffraction grating pattern is transferred (FIG. 1 (E)). reference).

According to this embodiment, metal (conductive thin film 3)
Since the adhesion between the metal and the metal (electroformed Ni layer 4) is stronger than the adhesion between the metal and glass, the conductive thin film 3 is peeled off from the glass substrate 1 adhered to the electroformed Ni layer 4, that is, the glass. Since the mold is removed between the substrate 1 and the conductive thin film 3, the diffraction grating pattern 2 can be accurately transferred to the stamper 5. Further, at the time of demolding, the excellent demolding property of the fluororesin uniformly dispersed in the conductive thin film 3 enables good demolding without peeling of the conductive thin film 3. Further, since the fluororesin uniformly dispersed in the conductive thin film 3 on the stamper 5 surface at the time of molding has an excellent releasability from the molding resin, the sticking of the resin, which easily occurs at the time of taking out the molded product, is suppressed. As a result, a good molded product can be taken out.

[0021]

Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. After setting the glass substrate 1 on which the diffraction grating pattern 2 is formed in the same manner as in Example 1, Cr is vapor-deposited by the electron beam heating vapor deposition method, and at the same time, the fluororesin is vaporized by the resistance heating method. Perform the original vapor deposition method. At this time, as shown in FIG. 2, the deposition rate is gradually changed to deposit the conductive thin film 3 to a thickness of 1000 Å. The composition ratio is changed so that the composition ratio of the fluororesin decreases toward the electroforming side as shown in FIG. Thereafter, electroforming, demolding and processing are performed in the same manner as in Example 1 to obtain a stamper 5 and a molded product 6 of PMMA resin or PC resin is obtained by an injection molding method.

According to the present embodiment, not only the same effects as in Embodiment 1 are obtained, but also the composition ratio of Cr and fluororesin of the conductive thin film 3 is gradually changed so as to directly contact the glass substrate 1. Since the ratio of the fluororesin in the conductive thin film 3 is increased, the releasability is further improved. Further, since the composition ratio of Cr in the portion which is in direct contact with the electroformed layer is high, the adhesion between the conductive thin film 3 and the electroformed layer 4 is improved. Therefore, it is possible to remove the mold with a small mechanical force. Further, at the time of molding, since the composition ratio of the fluororesin in the portion in contact with the resin is high, the mold release from the resin is excellent, and the molded product 6 can be taken out by a smaller mechanical force.

[0023]

Third Embodiment A third embodiment of the present invention will be described with reference to FIGS. 1, 4 and 5. After forming the diffraction grating pattern 2 on the glass substrate 1 in the same manner as in Example 1, the conductive thin film 3 is formed by the sputtering method. The target is formed of the conductive thin film 3 by a so-called two-way sputtering method in which Ni is sputtered using Ni and fluororesin, and at the same time, fluororesin is sputtered. At this time, as shown in FIG. 4, the input power of Ni and the fluororesin is gradually changed to form the conductive thin film 3 with a thickness of 500 Å. As shown in FIG. 5, the composition ratio is changed so that the composition ratio of the fluororesin decreases toward the electroformed layer side. Then, similarly to Example 1, electroforming, demolding, and processing are performed to obtain the stamper 5, and a molded product 6 of PMMA resin or PC resin is obtained by the injection molding method.

According to this embodiment, not only the same effects as in Embodiment 2 can be obtained, but also the kind of fluororesin which cannot be used because it is easily decomposed by heat in the vapor deposition method can be used. Becomes

[0025]

Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIG. A blazed diffraction grating pattern 7 as shown in FIG. 6 is formed on the glass substrate 1 in the same manner as in the first embodiment. next,
After forming the conductive thin film 3 in the same manner as in Example 2, electroforming, demolding, and processing are performed to obtain a stamper 8, and a molded product 9 of PMMA or PC is obtained by an injection molding method.

According to the present embodiment, not only the same effect as that of the second embodiment can be obtained, but also the blazed grating diffraction grating can be obtained.

[0027]

As described above, according to the present invention, since the mold is removed between the glass substrate and the conductive thin film, the diffraction grating pattern 2 can be accurately transferred to the stamper 5. Further, at the time of demolding, the excellent demolding property of the fluororesin uniformly dispersed in the conductive thin film enables good demolding without peeling of the conductive thin film. Further, at the time of molding, the fluororesin evenly dispersed in the conductive thin film on the stamper surface exhibits excellent mold release properties with the molding resin, and suppresses sticking of the resin that is likely to occur at the time of taking out the molded product, thus achieving good The molded product can be taken out.

Further, when the composition thin film having a gradient composition is used and the composition ratio of the fluororesin on the glass substrate side is increased, the mold release from the glass substrate and the mold release from the molded product are further improved, and
Adhesion with the electroformed layer is improved.

[Brief description of drawings]

FIG. 1 is a process chart showing Examples 1 to 3 of the present invention.

FIG. 2 is a graph showing vapor deposition rates of fluororesin and Cr in Example 2 of the present invention.

FIG. 3 is a graph showing the composition ratio of fluororesin and Cr in Example 2 of the present invention.

FIG. 4 is a graph showing vapor deposition rates of fluororesin and Cr in Example 3 of the present invention.

FIG. 5 is a graph showing the composition ratio of fluororesin and Cr in Example 3 of the present invention.

FIG. 6 is a process chart showing Example 4 of the present invention.

[Explanation of symbols]

 1 Glass Substrate 2 Diffraction Grating Pattern 3 Conductive Thin Film 4 Electroformed Ni Layer 5,8 Stamper

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

To solve this problem, Japanese Patent Laid-Open No. 30382/1990
A manufacturing method as disclosed in Japanese Patent No. 0 is shown. In this manufacturing method, after a pattern is formed on a glass substrate, a Ni film having a thickness of 500 Å or more is formed by a sputtering method or a vacuum evaporation method.
To form a first metal thin film. The first metal thin film is subjected to surface oxidation treatment with potassium dichromate or high-concentration ozone to form a release promoting film. A second metal thin film is formed on the surface of the release promoting film by the same means as the first metal thin film, and then a Ni layer is formed by electroforming . After the transfer, the stamper is obtained by demolding with the release promoting film as a boundary.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

In order to achieve the above-mentioned object, the present invention provides a conductive film for energization after forming a diffraction grating pattern on a glass substrate by using a resist, and applying the electroforming method. In the manufacturing method of obtaining a stamper by forming a Ni electroformed layer by removing the Ni electroformed layer, the conductive film is composed of a composite film of metal and fluororesin. Then, the conductive film may be manufactured by a physical film forming method. Further, the conductive film may be a gradient composition conductive film in which the composition ratio of the fluororesin decreases from the glass substrate side toward the Ni electroformed side.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

Next, the operation of the method of manufacturing a stamp for a diffraction grating of the present invention in the above steps will be described in detail. A desired diffraction grating pattern is formed on the glass substrate by photolithography using a resist. In order to obtain good diffraction efficiency, it depends on how accurately this diffraction grating pattern is transferred to the stamper in the subsequent steps. After forming an accurate pattern on the glass substrate, a conductive film for electroforming is formed.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

There are two types of film-forming materials for the electroconductive thin film, and one is a metal having electroconductivity, and Ni, Cr and the like are considered. Another film-forming material is a fluororesin, which has releasability. The characteristics of the fluororesin are that it is highly non-tacky and has excellent releasability because the surface energy is greatly reduced due to the strong bond energy between fluorine and carbon and the small polarizability. The above two kinds of materials are simultaneously formed on a substrate by using a dry process. The formed conductive thin film is a composite film in which the fluororesin is uniformly dispersed in the metal film. After forming the conductive thin film, Ni is formed by electroforming.
An electroformed layer is formed, and the transfer of the master is completed.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

After the glass substrate 1 is set in a vacuum vapor deposition apparatus, Cr is vaporized by an electron beam heating vapor deposition method and, at the same time, a fluororesin is vaporized by a resistance heating method. To form (Fig. 1
(See (B)). The composition ratio is approximately Cr: fluororesin =
It is formed with a thickness of 1000Å at 4: 6.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

According to this embodiment, metal (conductive thin film 3)
Adhesion between the metal (electroformed Ni layer 4) is a metal (conductive thin
Since the adhesion between the film 3) and the glass is stronger, the conductive thin film 3
Is separated from the glass substrate 1 that is in close contact with the electroformed Ni layer 4,
That is, since the mold is removed between the glass substrate 1 and the conductive thin film 3, the diffraction grating pattern 2 can be accurately transferred to the stamper 5. Further, at the time of demolding, the excellent demolding property of the fluororesin uniformly dispersed in the conductive thin film 3 enables good demolding without peeling of the conductive thin film 3. Further, at the time of molding, since the uniformly dispersed fluorine resin to the conductive thin film 3 of the stamper 5 surface has excellent releasability from the molding resin, to suppress the sticking of easy resin occurs during demolding Therefore, it becomes possible to take out a good molded product.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

[0021]

Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. After setting the glass substrate 1 on which the diffraction grating pattern 2 is formed in the same manner as in Example 1, Cr is vapor-deposited by the electron beam heating vapor deposition method, and at the same time, the fluororesin is vaporized by the resistance heating method. Perform the original vapor deposition method. At this time, as shown in FIG. 2, the deposition rate is gradually changed to deposit the conductive thin film 3 to a thickness of 1000 Å. As shown in FIG. 3, the composition ratio is changed so that the composition ratio of the fluororesin decreases toward the electroformed side. Thereafter, electroforming, demolding and processing are performed in the same manner as in Example 1 to obtain a stamper 5 and a molded product 6 of PMMA resin or PC resin is obtained by an injection molding method.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a process chart showing Examples 1 to 3 of the present invention.

FIG. 2 is a graph showing vapor deposition rates of fluororesin and Cr in Example 2 of the present invention.

FIG. 3 is a graph showing the composition ratio of fluororesin and Cr in Example 2 of the present invention.

[Fig. 4] Fluorine resin and Ni in Example 3 of the present invention
It is a graph showing the input power of.

FIG. 5 shows a fluororesin and Ni in Example 3 of the present invention .
It is a graph which shows the composition ratio of.

FIG. 6 is a process chart showing Example 4 of the present invention.

Claims (3)

[Claims] 1. A stamper is obtained by forming a diffraction grating pattern on a glass substrate using a resist, forming a conductive film for electric conduction, forming an Ni electroformed layer by an electroforming method, and then demolding. The method for producing a stamper for a diffraction grating, wherein the conductive film comprises a composite film of metal and fluororesin. 2. The method for manufacturing a stamper for a diffraction grating according to claim 1, wherein the conductive film is manufactured by a physical film forming method. 3. The diffraction grating according to claim 1, wherein the conductive film is a gradient composition conductive film in which the composition of the fluororesin decreases from the glass substrate side toward the Ni electroformed side. Stamper manufacturing method.