JPH01300443A - Production of substrate for information recording medium and substrate obtained by this method - Google Patents

Abstract

PURPOSE:To improve mass productivity and to reduce cost by forming the latent images corresponding to the guide grooves of a substrate for information recording media to be finally obtd. onto a photosensitive resin film provided on the substrate, then developing the same. CONSTITUTION:The photosensitive resin film 3 consisting of a positive type photoresist is formed atop the light transparent substrate 1 having a through-hole 2 in the central part. The photoresist is then selectively exposed by a UV contact exposing method using a photomask 4 having the pattern corresponding to the guide grooves of the substrate for the information recording medium to be finally obtd. and UV rays 5 to form the latent images corresponding to the guide grooves. The photosensitive resin 3 after the exposing is then developed by using an alkaline developing soln. and is subjected to washing and drying treatments to obtain the photosensitive resin patterns 3a; thereafter, the patterns are subjected to a heat treatment, by which the substrate having the photosensitive resin patterns 3a and the guide grooves 6 formed by the light transparent substrate 1 between the patterns is obtd. The mass production of the product and the reduction of the cost by the simplification of the stages are attained in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a substrate used in an information recording medium such as a magneto-optical recording medium or an optical recording medium, and to a U-plate obtained by this b-drop.

[Prior Art] When information recording media such as magneto-optical recording media and optical recording media are written, or when reading information recorded on these recording media, a spreading means or In order to enable the reading means to accurately scan (track) a predetermined portion of a recording medium, a concave-convex pattern (hereinafter referred to as a guide groove) for guiding is formed in advance on the surface of the substrate on which these recording media are formed. something is being used.

Conventionally, there have been two 7+ methods as follows for manufacturing a substrate for an information recording medium having such a guide surface of '4Fi.

The first method is called the direct etching method, in which a resist film (photosensitive resin film) is deposited on the surface of the glass substrate.
After coating the resist film, a latent image corresponding to the guide groove is formed on the resist film by means such as laser cutting, and then the resist film with the latent image formed thereon is developed to form a resist pattern. After that, glass with resist pattern! ! After performing dry etching on the roots, the resist is removed to obtain a substrate for an information recording tR body in which a guide surface is formed on the surface of the glass substrate (for example, as disclosed in Japanese Patent Laid-Open No. 59-210547). reference).

The second method is so-called 2Pa, in which liquid photosensitive resin (photopolymer ), then stamping is performed by pressing a glass substrate onto the surface of the stamper, and the photosensitive resin is sandwiched between the glass substrate and the stamper so that the photosensitive resin forms the uneven pattern of the stamper. The photosensitive resin is completely filled and evenly adhered to the surface of the glass substrate, and then the photosensitive resin is cured by applying ultraviolet rays from the back surface of the glass substrate,
Thereafter, the stamper is peeled off, and a two-layer M4 information recording medium substrate, on which a resin having a concavo-convex pattern formed on the surface of the glass substrate is closely adhered, is attached.

[Problem to be solved by the defense] However, in the first method (direction planning>1.), the bottom surface of the guide groove is made smooth before the guide groove is formed by coating the crow 11. This is rotation', and also laser cutting, development,
Tri-etching culms must be carried out sequentially, and the equipment used to carry out these steps is expensive, which is disadvantageous in terms of workability and production cost.

The second method (2P method) also evaluates heat resistance, hardness, durability, bonding between the glass substrate and the photosensitive resin, removability from the stamper, etc. for the 1q information recording medium substrate. In recent years, when there is a demand for a dramatic increase in recording density, it is not always easy to obtain a high-quality information recording medium substrate that can meet this demand. Another drawback is that it takes time and money to produce the stamper.

Therefore, the object of the present invention is to solve the above-mentioned drawbacks of the prior art,
A method for manufacturing an information recording medium substrate that satisfies various properties required for an information recording medium substrate at a low cost of 1 to 11, and information recording produced by this method. 1. To provide substrates for media.
[Means for Solving the Problems] The present invention has been made to achieve the above-mentioned problems, and the method for manufacturing a substrate for an information recording medium of the present invention is a method for manufacturing a substrate for an information recording medium. A resin film is formed, and then a latent image corresponding to M of the finally obtained information recording medium substrate is formed on the photosensitive resin film, and then the photosensitive resin film on which the latent image is formed is formed. is developed to form a photosensitive resin pattern,
The guide groove is formed by the photosensitive resin pattern.

[For 0] According to the conventional direct etching method, a resist film (photosensitive resin film) provided on a glass substrate is laser cut and then developed to obtain a resist pattern. 1- on the board with
A glass pattern is formed by etching the portion of the glass substrate where the resist pattern does not exist to a predetermined depth using lie etching, and then the resist pattern is peeled off, so that the guide surface is formed by a crow pattern. Information recording media substrates were brought in,
According to the method of the present invention, a latent image corresponding to the guide surface of the ultimately obtained information recording medium substrate is formed on the photosensitive resin film provided on the substrate, and then the latent image is developed. Since the guide vortex was formed by the photosensitive resin pattern obtained by this method, dry etching and resist pattern peeling in the direct etching method were impaired, and
Through this simplification, products can be produced sooner and at lower costs. In addition, according to the direct etching method, the bottom surface of the guide groove was rotated to make it flat in order to etch the glass substrate, but according to the method of the present invention, the surface smoothness is achieved by polishing in advance. Raised glass substrate or flat surface NF
Since the plastic substrate with a high degree of 4 degrees can be used as the bottom surface of the guide groove, the accurate i~racking at the information mark, medium (A) will be cut.

According to the conventional 2P method, in order to form the guide groove,
Stamp bar with a pattern corresponding to the guide groove formed on the surface
However, the method of the present invention is easier to manufacture than the above-mentioned stamper due to the formation of the guide groove. It is excellent in that a mask etc. can be used. In addition, in 2P6i, the thickness of the photosensitive resin between the glass substrate and the stand bar must be as thick as several μm to several 1 μm, so the scum generated during the curing of the photosensitive resin will be inside the cured resin. The occluded gas is easily occluded by the resin, leading to a decrease in the physical properties of the cured resin (e.g. hardness, durability, etc.), and the occluded gas is then gradually released, resulting in a decrease in the adhesion between the glass substrate and the cured resin. However, according to the method of the present invention, the thickness of the photosensitive resin film can be reduced, so that the above-mentioned problems with the 2P method do not occur.

[Example] First, an example of a method for manufacturing an information recording medium substrate of the present invention will be explained with reference to FIG.

Made of sortalime glass, outer diameter 13 Q #II+
A crow disk with lφ, inner t ¥15m+φ, and thickness of 1.2mm was heated to a temperature of 400℃ after rubbing the surface of the mountain soil with lees.
After chemically strengthening it by immersing it in molten potassium nitrate salt set to A transparent substrate 1 (surface roughness: 40 people) was obtained.

On the upper surface of this translucent substrate 1, a novolac positive type film 7 is placed.
11-Resist (Tokyo Ohka Kogyo Co., Ltd. 1 block SMR890
0) to a film thickness of 1000 mm to form a photosensitive resin film 3 made of positive type photoresist (see FIG. 1).

Next, the photosensitive resin film 3 consisting of this positive type A-regis I is coated with an A upper mask 4 and ultraviolet rays 5 (having a pattern corresponding to the guide groove of the information recording medium substrate to be finally 1q). (See FIG. 1(c)) by selectively exposing to the ultraviolet rays using the ultraviolet close exposure method used to form a latent image corresponding to the guide groove.

Next, the exposed photosensitive resin film 3 is developed using an alkaline developer (Tokyo Ohka Kogyo Co., Ltd. NMD-W), washed with water, and dried to obtain a photosensitive M resin pattern 3a. Heat treatment at 150'C using oven 3
0 minutes 1) Guide grooves 6 are formed in the photosensitive resin patterns 3a, 3a and the transparent substrate 1 between them.
The information recording medium substrate of the present invention having (19) (first
Figure (see Q).

Next, on the information recording medium substrate with the guide grooves shown in this example, silicon was used as a target and 8r was used as a reactive gas.
A nitrided I4 film with a thickness of 800 mm was formed using a reactive sputtering method using a mixed gas of N2 and N2 (△r/N2=2/1), a pressure of 10 mTorr, and a high frequency power of 1 K.
First, a translucent zero layer made of an elementary film is formed, and on top of that,
The target was TbFeCo, the gas was Ar, the pressure was 10 m 1 orr, and the high frequency power was 0.5 -
Next, a magnetic layer consisting of ~1000 terbium-iron-cobalt film is formed by sputtering using sputtering, and on top of that, silicon is used as a target, and a reactive gas (A) is mixed with N2. Dregs (Ar, /N
2 = 2/1), a reactive sputtering method using 10 mTorr as the H force and 1 as the high frequency power was used to form a temporary layer of silicon nitride with a film thickness of 2000 mm, thereby forming a magneto-optical recording medium. I got it.

Regarding the destroyed magneto-optical recording medium, I used Scotch tape (manufactured by 3M, USA) to examine the density of the guide fi After pasting the film (product name: 100ml), it was peeled off and subjected to Peel Test 1, but no peeling occurred.

Furthermore, the magneto-optical recording medium was subjected to a heat cycle test (10 cycles) under the conditions of 25°C on the low temperature side and 150°C on the high temperature side, holding time for 1 hour each, and atmospheric depletion/degradation rate of 50°C/min. After conducting the same beer test as described above, it was found that the film did not peel off, was stable against heat, and had M-thermal properties.

It was found that the magneto-optical and recording/reproducing characteristics of the magneto-optical distribution B and W bodies thus obtained were equivalent to those of magneto-optical recording media using substrates obtained by the conventional direct etching method.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, but includes the second application example and modification example below.

(1) As the translucent substrate, a soda lime glass substrate was used in the examples, but in addition to soda lime glass, aluminoborosilicate glass, porosilicate glass,
A glass substrate such as quartz glass may also be used. Further, in the embodiment, a glass substrate that was subjected to chemical strengthening treatment and then silazane treatment was used, but chemical strengthening treatment and silazane treatment are not essential, and one or both of them may be omitted depending on the case.

As a transparent substrate, a plastic substrate may be used instead of a glass substrate, and a typical example is polycarbonate.
1 to 1, substrates made of polymethyl methacrylate, epoxy resin, etc. can be mentioned. Moreover, sapphire can also be used as a substrate.

(2) As the material for the photosensitive resin film formed on the light-transmitting substrate 10, positive-type resists other than the novolac-based plastic A-resist used in the examples, polyvinyl cinnamate, etc. A negative photoresist award-winning negative photoresist 1- made of a resin based on the negative photoresist is used.

Further, the photosensitive resin film is determined depending on the desired depth of the guide groove, but it is preferably 300 to 1,500 depth.

(3) In order to form a latent image corresponding to the guide groove on the photosensitive resin film, ultraviolet close exposure was used in the example, but Haku's ultraviolet I2 exposure method, such as close exposure method or projection light method, may also be used. But it's okay. Alternatively, a laser cutting method may be used.

Note that the pattern of the photomask used when forming a latent image using a photoresist differs depending on whether the photosensitive resin film is a positive 3+1 photoresist or when the photoresist is a negative type film. If a positive pattern is used for a positive photoresist, it is necessary to use a negative pattern for a negative photoresist on the rear right.

(4) In order to form a photosensitive resin pattern by developing the photosensitive resin film on which the latent image has been formed, a wet developing process using an alkaline developer was adopted in the example. A developer may also be used. An appropriate developer can be selected depending on the type and properties of the photosensitive resin film1, and a dry development process can also be used instead of a wet development process9.

(5) In the example, a substrate for an information recording medium was used in which the light-transmitting substrate was exposed after development, and the surface of the light-transmitting substrate formed the bottom surface of the guide groove, but it was found that exposure to ultraviolet rays quickly adjusted the current level. By this, a relatively shallow guide groove may be formed,
In this case, the photosensitive resin forms the bottom surface of the guide groove.

(6) In the Examples, the photosensitive resin pattern after development, washing with water, and drying was treated with solvents (for example, methylcellosolve acetate) and various gases (
For example, H20, N2.02.

Although heat treatment was performed at 150° C. for 30 minutes to promote evaporation, release, and removal of CxHy)I1, this heat treatment is not essential and can be omitted in some cases. When performing heat treatment, it is preferable that the temperature is 100°C or higher; however, if the temperature exceeds 200"C, it is not preferable because the heat will cause photosensitivity [decomposition of the resin pattern to ML]. However, the Mannaiki nail method In this case, it can be used even if the temperature is raised to 200°C.

[Effects of the Invention] As detailed above, according to the present invention, it has become possible to obtain a substrate for information recording media with excellent characteristics as a thick plate for information recording media with good mass production efficiency and at low cost. .

[Brief explanation of the drawing]

FIG. 1 shows an r-cycle diagram for the method of the present invention. 1... Transparent substrate 2... Through hole 3... Photosensitive resin film 3a... Photosensitive resin pattern 4... Photomask 5... Ultraviolet rays 6... Guide groove

Claims (1)

[Claims] 1. Forming a photosensitive resin film on a light-transmitting substrate, and then forming a latent image on the photosensitive resin film corresponding to the guide groove of the information recording medium substrate to be finally obtained. Then, the photosensitive resin film on which the latent image has been formed is developed to form a photosensitive resin pattern, and the guide groove is formed by the photosensitive resin pattern. Production method. 2. An information recording medium substrate obtained by the method according to claim 1, in which guide grooves are formed by a photosensitive resin pattern.