JPH10254335A - Manufacture of hologram element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a high quality resin hologram element by efficiently utilizing the energy of ultraviolet rays when a fine pattern is formed on the both surfaces of a light transmissive substrate. SOLUTION: A first light transmissive original plate 2 (a) has a reflective surface 4 (a metallic thin film) on the rear side of the surface having a fine pattern. The surface having the pattern of the plate 2 (a) and a light transmissive substrate 1, and the substrate 1 and the surface having the pattern of a second light transmissive original plate 2 (b) are abutted through an ultraviolet ray hardening resin 3 respectively. Then, a pressure force is applied so that the resin 3 fills the patterns of the plates 2, ultraviolet rays are irradiated from the rear surface side of the plate 2 (b) so that the resin 3 is hardened along the fine pattern shapes of the both plates 2. Then, the plates 2 are separated from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CD, a CD-RO
The present invention relates to a method for manufacturing a hologram element used for an optical disk pickup component such as an M, MD, or LD.

[0002]

2. Description of the Related Art A hologram element used as a pickup part for an optical disk is usually several mm square, and a plurality of hologram elements are collectively mounted on a large light-transmitting substrate for the purpose of mass production at low cost. After the individual elements are formed, they are provided by being divided.

A very fine diffraction grating is precisely formed on a hologram element. As a method of forming the diffraction grating, a method using the method of manufacturing a semiconductor device shown in FIG. 5 and a molding method generally called a photopolymer method (hereinafter referred to as a 2P method) shown in FIGS. Various manufacturing methods such as a manufacturing method have been proposed.

In a method of manufacturing a hologram element using a method of manufacturing a semiconductor device, as shown in FIG. 5, a photosensitive material 12 is first applied to one surface of a glass substrate 11 by spin coating or the like. Next, a predetermined pattern is formed by photolithography. Thereafter, a fine pattern is formed on the glass substrate 11 by a reactive ion etching method in a gas atmosphere such as CF ₄ or CHF ₃ . At this time, the photosensitive material 12 is also processed at the same time. After that, the applied thickness of the photosensitive material 12 is determined so that the photosensitive material 12 remains on the glass substrate.
The photosensitive material 12 remaining on the glass substrate 11 is removed with a solvent or is ashed and removed in an oxygen gas atmosphere. The plurality of hologram elements formed on the glass substrate 11 by the above method are completed by being finally divided into a required shape.

In the manufacturing method shown in FIG. 5, a large amount of time is required for the reactive ion etching step, and the manufacturing efficiency is not improved. Therefore, one of the more efficient and inexpensive manufacturing methods is shown in FIGS. A method using the 2P method shown has been proposed.

[0006] In the method of manufacturing a hologram element by the 2P method shown in FIG. 6, an ultraviolet-curable liquid resin 3 is applied on a master 2 previously prepared, and light is applied to the master 2 via the ultraviolet-curable liquid resin 3. The transparent substrate 1 is arranged. Next, the UV-curable resin 3 is sufficiently pressed and spread over the space formed by the substrate 1 and the master 3 while pressing, if necessary. Then, the resin 3 is irradiated with ultraviolet rays.
The substrate 1 and the master 3 are then peeled off. The UV-curable liquid resin 3 may be made of a material that has better adhesion to the light-transmitting substrate 1 than the master 2 after curing, or may be pre-treated to improve the adhesion to the light-transmitting substrate. Then, a resin layer having a transfer pattern of the master 2 is formed on the light transmitting substrate 1.

FIG. 5 shows a method in which an element is formed only on one surface of the glass substrate 11. However, when a tracking beam generation function and an optical branching / error signal generation function are integrated in one hologram element, It is necessary to form diffraction gratings positioned on both sides of the glass substrate.

However, in the conventional method shown in FIG. 5, it is difficult to form a diffraction grating on both sides at once, and after forming an element on one side, the same steps are followed to form an element on the other side. Is adopted.

On the other hand, in the photopolymer method, as shown in FIG. 7, by using a substrate 1 transmitting ultraviolet rays and masters 2 and 2 transmitting ultraviolet rays, it is possible to collectively form elements on both sides. It can be expected that the production efficiency will be improved.

[0010] When simultaneously forming a double-sided pattern, at least one master is made of a material that transmits ultraviolet light. For example, as shown in FIG. 8, when a master 2 that transmits only ultraviolet light is used, the materials of the two masters 2 and 7 are different. For example, when a temperature change such as a temperature rise during molding occurs, the expansion coefficient is increased. , The two masters 2, 7 have different elongations. For this reason, there has been a problem that the positions of the fine patterns on both surfaces are shifted.

As the master 7 which is not an ultraviolet-transmitting master,
Generally, a metal plate called a stamper is used.
The metal stamper 7 is formed by forming a conductive thin film on a glass master having a fine pattern by a sputtering method or the like, and forming the conductive thin film into a plate having a thickness of about 0.2 to 0.3 mm by using an electroforming technique. 2 using such a thin metal stamper 7
In the P molding, there is a problem that if the molding is performed hundreds to thousands of times in the process of releasing the metal stamper 7 from the substrate 1, the metal stamper 7 is deformed. Therefore, a method of joining a reinforcing member to the back surface of the stamper 7 has been adopted (for example, see Japanese Patent Application Laid-Open No. 3-230336).

In view of the above problems, when a fine pattern is to be simultaneously formed on both surfaces, as shown in FIG. 7, a substrate 1 that transmits ultraviolet light and two masters 2 that transmit ultraviolet light. In addition, there is a method of forming an element by performing collective processing on both surfaces by using No. 2 and No. 2.

According to this method, by using the same material for the two masters 2, the displacement of the double-sided pattern due to a temperature change can be eliminated, and a relatively thick rigid body such as quartz glass is used. As a result, the life of the master can be greatly extended, and molding on the order of thousands of sheets is possible. Further, it is not necessary to take a troublesome method of producing a stamper and backing it.

[0014]

However, in the case of using two ultraviolet transmitting masters 2 and 2 as described above, most of the ultraviolet light is transmitted, so that more ultraviolet irradiation energy is required as compared with the prior art. is there. Excessive consumption of ultraviolet irradiation energy shortens the life of the ultraviolet irradiation lamp, resulting in an increase in equipment and equipment costs.

Therefore, the present invention relates to a method for manufacturing a hologram element in which a fine pattern is simultaneously formed on both surfaces by a photopolymer method, while utilizing an ultraviolet irradiation energy as efficiently as possible while using an ultraviolet transparent master such as a quartz material as it is. An object of the present invention is to provide a low-cost and mass-producible 2P molding method by providing a reflecting member.

[0016]

In order to solve the above-mentioned problems, a method for manufacturing a hologram element according to the present invention is characterized in that, in claim 1, first and second light-transmitting masters are used. The light-transmitting master has a reflective surface on the back side of the surface having the fine pattern, the surface having the fine pattern of the first master, a light-transmitting substrate, and the substrate and the second light-transmitting master. A step of bringing the surfaces having the fine pattern into contact with each other via an ultraviolet-curable resin, a pressing step of applying pressure to the resin so as to fill the fine pattern of the master with the resin, and a second step. An exposure step of irradiating ultraviolet rays from the back side of the light-transmitting master to cure the ultraviolet-curable resin according to the fine pattern shape of both masters, and a release step of peeling off the substrate and both masters. It is characterized by the following.

In the present invention, the first and second light-transmitting masters have a diffuse reflection surface having a surface roughness Rmax of 100 μm or more on the back surface side of the surface having the fine pattern. The surface having the fine pattern of the first master and the light-transmitting substrate, and the surface having the fine pattern of the substrate and the second light-transmitting master are respectively in contact with each other via an ultraviolet curable resin. Contacting, applying pressure to these to press the resin so as to fill the fine pattern of the master, and irradiating ultraviolet rays from the back side of the second light-transmitting master to cure the ultraviolet-curable resin. The present invention is characterized in that it has an exposure step of curing according to the fine pattern shapes of both masters and a release step of peeling off the substrate and both masters.

According to a third aspect of the present invention, the first and second light-transmitting masters are used. The first light-transmitting master has a reflective surface and a surface roughness Rmax of 100 μm or more on the back side of the surface having the fine pattern. The surface having the fine pattern of the first master and the light-transmitting substrate, and the surface having the fine pattern of the second light-transmitting master, each having an irregular reflection surface, and And a pressing step of applying pressure to these so that the resin fills the fine pattern of the master, and irradiating ultraviolet rays from the back side of the second light-transmitting master to emit ultraviolet rays. The method includes an exposure step of curing the curable resin according to the fine pattern shapes of both masters, and a release step of peeling the substrate and both masters.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the following embodiments.

FIGS. 1, 2, 3 and 4 show first, second, third and fourth embodiments according to the present invention. In each case, a light-transmitting substrate is brought into contact with two light-transmitting masters having a predetermined fine pattern via an ultraviolet-curable resin, and a pressure step of pressing, an exposure step of irradiating ultraviolet rays, and a separation step The mold process is shown.

1 to 4, the masters 2 (a) and 2 (b) are brought into contact with the light-transmitting substrate 1 via the ultraviolet-curable liquid resin 3, and the resin starts to spread due to the pressing force. The pressure was maintained for a certain period of time from the point of time. A 100-mm square acrylic resin substrate (Sumipec grade name E011 extruded plate manufactured by Sumitomo Chemical Co., Ltd.) was used as the light-transmitting substrate 1, and the substrate was immersed and washed in pure water and isopropyl alcohol by applying ultrasonic waves for 2 minutes each. Drying was performed. Thereafter, as a primer treatment, an N-vinyl-2-pyrrolidone solvent was dropped on the substrate, and spin-coating was performed at 3000 rpm and 2 rpm.
The coating was performed for 0 to 30 seconds and allowed to dry naturally for 30 minutes.

As the UV-curable liquid resin 3 (Dyram M-121 or M-107 manufactured by Mitsubishi Rayon Co., Ltd.), a resin having a viscosity of 330 to 770 cps was used. The pressure and exposure conditions were a pressure of about ² to 4 kg / cm ² and an ultraviolet irradiation time of about 20 seconds. At this time, the film thickness of the ultraviolet curable resin was 10 to 30 μm. Eye cure light (M04-141 manufactured by Eye Graphics Co., Ltd.) was used as the energy source of the ultraviolet light of the ultraviolet irradiation device. The distance between the light and the molding was about 120 cm.

Each of the masters 2 and 2 has a diameter of 125 mm and a thickness of 3
The fine pattern was transferred to the master using quartz with a thickness of 2 mm, and was fabricated by photolithography using a photomask by contact exposure.

Example 1 Using the substrate, the washing, the primer treatment, and the ultraviolet curable resin, as shown in FIG. A Ni thin film was formed as a reflective surface 4 on the back surface of the surface having the fine pattern of the light-transmitting master 2 (a) by a sputtering method. At this time, the thickness of the metal thin film was 1000 to 1200 °.

The master 2 (a) is brought into contact with the light-transmitting substrate 1 via an ultraviolet-curable resin 3, and
With the light-transmissive master 2 (b) of FIG. The pressure was 3 kg / cm ² , and the pressure holding time was 180 seconds. Ultraviolet rays were irradiated for 20 seconds from the second transparent master 2 (b) side. After a while
The substrate 1 and the masters 2 and 2 were released.

After the release, it was confirmed that a fine pattern was formed on the entire surface of the substrate 1. In addition, a tape peeling test was performed, and it was confirmed that resin peeling did not occur on the entire surface of the substrate 1. Further, after the molding was performed 1,000 times, the displacement of the double-sided pattern of the substrate 1 did not exceed the specification of ± 20 μm. Further, there was no trouble in performing the molding.

Example 2 Using the substrate, the cleaning, the primer treatment, and the ultraviolet-curable resin, as shown in FIG. The reverse side of the surface having the fine pattern of the light-transmitting master 2 (a) was Rmax200 to 300 μm by a tape polishing method.
(Rough reflection surface 5).

The master 2 (a) is brought into contact with the light-transmitting substrate 1 via an ultraviolet-curable resin 3, and the substrate 1 and the second
With the light-transmissive master 2 (b) of FIG. The pressure was 4 kg / cm ² , and the pressure holding time was 180 seconds. Ultraviolet rays were irradiated for 20 seconds from the second transparent master 2 (b) side. After a while
The substrate 1 and the master 2 were released.

After releasing, it was confirmed that a fine pattern was formed on the entire surface of the substrate 1. In addition, a tape peeling test was performed, and it was confirmed that resin peeling did not occur on the entire surface of the substrate 1.

Example 3 The same washing and the same primer treatment were carried out on the same substrates as in Examples 1 and 2, and two light-transmitting masters 2 and 2 were used as shown in FIG. The back surface of the surface having the fine pattern of the first light-transmitting master 2 (a) is Rmax200 to 300 by a tape polishing method.
The surface was processed to a surface roughness of μm, and an Ni metal thin film was formed on the irregular reflection surface 5 by sputtering as the reflection surface 4 at a thickness of 400 °.

The master 2 is irradiated with the UV-curable resin 3
(A) was brought into contact with the light-transmitting substrate 1, and the substrate was brought into contact with the second light-transmitting master 2 (b) via the ultraviolet-curable resin 3 and pressed. The pressure was 4 kg / cm ² , and the pressure holding time was 180 seconds. Second optically transparent master 2
Ultraviolet rays were irradiated from the side (b) for 20 seconds. After a while
The substrate 1 and the masters 2 and 2 were released.

After the release, it was confirmed that a fine pattern was formed on the entire surface of the substrate 1. In addition, a tape peeling test was performed, and it was confirmed that there was no peeling from the resin on the entire surface of the substrate 1.

Example 4 The same washing and the same primer treatment were carried out on the same substrates as in Examples 1 and 2, and two light-transmitting masters 2 and 2 were used as shown in FIG. A metal reflector 6 made of stainless steel is installed on the back of the surface having the fine pattern of the first light-transmitting master 2 (a), and the first master 2 (a) is transparent to the master 2 (a) through the ultraviolet curing resin 3. The substrate 1 was brought into contact with the substrate 1, and the substrate 1 was brought into contact with the second optically transparent master 2 (b) via the ultraviolet-curable resin 3 and pressed. The pressure was 2 kg / cm ² , and the pressure holding time was 150 seconds. UV light is applied from the side of the second transparent master 2 (b).
Irradiated for 0 seconds. After the ultraviolet irradiation, the substrate and the master were released from the mold.

After the release, it was confirmed that a fine pattern was formed on the entire surface of the substrate 1. In addition, a tape peeling test was performed, and it was confirmed that there was no peeling from the resin on the entire surface of the substrate 1.

Comparative Example 1 A double-sided pattern was formed by the method shown in FIG. Two master disks 2, 2 that transmit ultraviolet light
As in Example 1, quartz having a diameter of 125 mm and a thickness of 3 mm was used, and the transfer of a fine pattern to the masters 2 and 2 was performed using a photolithography technique and a contact mask made of a photomask.

The same washing and the same primer treatment are performed on the same substrate as in the above embodiment, and the same ultraviolet-effect resin 3 as in the above embodiment is dropped on both surfaces thereof, and the pressure is 3 kg / cm.
^{2. The} pressure holding time was 150 seconds. UV irradiation 2
This was performed for 0 seconds, and the substrate 1 and the masters 2 and 2 were released from the mold. After release, an uncured portion was formed on a part of the outer periphery of the substrate. In addition, a tape peeling test was performed. As a result, peeling occurred at a part of the outermost peripheral portion.

Comparative Example 2 A double-sided pattern was formed by the method shown in FIG. The same washing and the same primer treatment were carried out on the same substrate as in Example 1 and Example 2, and the above-mentioned ultraviolet-effect resin was dropped on both surfaces of the substrate. The master 1 is a quartz master similar to the above embodiment, the master 7 is a metal stamper, a Ni conductive thin film is formed on a glass master having a fine pattern by a sputtering method, and the thickness is about 0.2 mm using an electroforming technique. It is formed on a plate. Pressure is 3kg / cm
^{2. The} pressure holding time was 150 seconds. UV irradiation 2
This was performed for 0 second, and then the substrate and the master were released.

After the release, it was confirmed that a fine pattern was formed on the entire surface of the substrate 1. In addition, a tape peeling test was performed, and it was confirmed that there was no peeling from the resin on the entire surface of the substrate 1. However, in about 100 times of 2P molding, the displacement of the double-sided pattern on the substrate is 30 to 40 μm.
Exceeded the specification ± 20 μm. Also, after 200 times of 2P molding, the deformation of the stamper became remarkable, the spread of the resin was not uniform, and it became impossible to continue molding.

[0039]

As is apparent from the above description, the method for manufacturing a hologram element according to the present invention is capable of forming a fine pattern on the first light-transmitting master when forming fine patterns on both surfaces of the light-transmitting substrate. The light energy utilization efficiency of ultraviolet light can be improved by the reflecting surface of the metal thin film, the reflecting member, or the like provided on the back surface of the surface having the light. Also, the back surface of the light-transmitting master having the fine pattern is Rmax10
When the irregular reflection surface has a surface roughness of 0 μm or more, the ultraviolet energy is irregularly reflected at the time of exposure, so that the light energy use efficiency can be improved. Further, the reflection surface and Rma
When the irregular reflection surface having a surface roughness of 100 μm or more is used in combination, the light energy at the time of exposure is scattered and reflected, and the light energy can be used more efficiently.

In each of the above claims, since the material of the light-transmitting master is the same, no displacement of the double-sided pattern occurs, and the thickness of the master is 3 mm, which is thicker than the conventional metal stamper. Therefore, even if molding is performed 1,000 times, there is no problem in molding. Furthermore,
By installing a reflective member on the back side of the surface having the fine pattern of such a light-transmitting master, the support member, vacuum suction hole, screw hole, etc., which are arranged on the back of the master, affect the light rays during ultraviolet exposure. It was possible to prevent the correct formation of the fine pattern from being hindered by the application.

[Brief description of the drawings]

FIG. 1 is a process chart for explaining a first embodiment according to the present invention.

FIG. 2 is a process diagram illustrating a second embodiment according to the present invention.

FIG. 3 is a process diagram illustrating a third embodiment according to the present invention.

FIG. 4 is a process chart for explaining a fourth embodiment according to the present invention.

FIG. 5 is a process diagram illustrating a method for manufacturing a hologram element using a conventional method for manufacturing a semiconductor element.

FIG. 6 is a process diagram illustrating a method of manufacturing a hologram element by a photopolymer method.

FIG. 7 is a process diagram illustrating a method for manufacturing a hologram element by a photopolymer method.

FIG. 8 is a process chart for explaining a method of manufacturing the hologram element used in the second comparative example.

[Explanation of symbols]

 Reference Signs List 1 light-transmitting substrate 2 light-transmitting master 3 ultraviolet-curable liquid resin 4 reflection surface (metal thin film) 5 diffuse reflection surface 6 reflection plate

Claims (3)

[Claims] A first light-transmitting master having a reflection surface on a back surface side of a surface having a fine pattern, wherein the first light-transmitting master has a fine surface; A step of bringing the surface having the pattern and the light-transmitting substrate, and the substrate and the surface having the fine pattern of the second light-transmitting master into contact with each other via an ultraviolet-curable resin; A pressing step of pressing the resin so as to fill the fine pattern of the master; and irradiating ultraviolet light from the back side of the second light-transmitting master to cure the ultraviolet-curable resin according to the fine pattern shape of both masters. A method of manufacturing a hologram element, comprising: an exposing step of exposing; and a releasing step of separating the substrate and both master disks. 2. A method according to claim 1, wherein the first and second light-transmitting masters have a diffuse reflection surface having a surface roughness of Rmax 100 μm or more on the back surface side of the surface having the fine pattern. Contacting the surface having the fine pattern of the first master with the light-transmitting substrate, and the surface having the fine pattern of the second light-transmitting master with the ultraviolet-curable resin; A pressurizing step of applying pressure to the resin to fill the fine pattern of the master, and irradiating ultraviolet rays from the back side of the second light-transmitting master to apply an ultraviolet curable resin to both masters. A method for manufacturing a hologram element, comprising: an exposure step of curing according to a fine pattern shape; and a release step of separating a substrate and both master disks. 3. The first and second light-transmitting masters each having a reflecting surface and a diffusely reflecting surface having a surface roughness of Rmax 100 μm or more on the back side of the surface having the fine pattern. The surface of the first master having the fine pattern and the light-transmitting substrate, and the surface of the substrate and the second light-transmitting master having the fine pattern are each interposed through an ultraviolet curable resin. A step of contacting them, a pressure step of applying pressure to the resin to fill the fine pattern of the master, and irradiating ultraviolet rays from the back side of the second light-transmitting master to cure the ultraviolet-curable resin. A method for manufacturing a hologram element, comprising: an exposure step of curing according to the fine pattern shapes of both masters; and a release step of separating the substrate and both masters.