JPH04184727A - Manufacture of optical disc stamper - Google Patents

Abstract

PURPOSE:To obtain a high density optical disc without fail by a method wherein, after a glass substrate surface is subjected to a coupling agent treatment, a photoresist layer is formed and apertures corresponding to recorded information are formed in the photoresist layer by exposure and development and recesses corresponding to recorded information are formed by etching and, after metal plating is applied, the metal plating layer is removed. CONSTITUTION:A glass substrate surface 11a is treated with coupling agent containing metal atoms such as Si and Ti which have hydrophilic groups on one side of the atoms and lipophilic groups on the other. Then the glass substrate surface 11a is coated with photoresist 12 and the photoresist layer is exposed and developed into a required pattern to form apertures 13. Then the glass substrate surface 11a is etched through the apertures 13 by using the photoresist 12 as etching resist to form recesses 14 and the photoresist is removed. Then metal plating is applied to the glass substrate surface 11a. With this constitution, a stamper for forming a high density recording optical disc can be obtained without fail.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing an optical disc standber used for producing optical discs such as video discs, compact discs, and magneto-optical discs, particularly optical discs with high density recording. Involved.

[Summary of the invention]

The present invention relates to a method for producing a standber for an optical disc,
After applying a coupling agent treatment to the glass substrate surface, a photoresist is formed, and an opening corresponding to the recorded information is formed in this through exposure and development treatment, and the glass substrate surface is etched using this photoresist as a mask. A concave portion corresponding to recorded information is formed on the glass substrate surface, metal plating is applied to this glass substrate surface, and this metal plating layer is peeled off from the glass substrate surface and used as a stamper for obtaining an optical disk.
1 or a metal mask for obtaining this stamper, and thus it is possible to reliably obtain a stamper for forming a high-density recording optical disk.

[Conventional technology]

For example, as shown in the process diagram in FIG. 4, a method for obtaining optical discs such as video discs, compact discs, magneto-optical discs, etc. is as follows: A photoresist (2) is applied to the entire surface, exposed in a pattern according to the information to be recorded, and then developed to form openings (3) in the required pattern (the first Figure 4A).

Next, a metal such as Ni is deposited on the entire surface including the inside of the opening (3) by electroless plating, vapor deposition sputtering, etc. for subsequent electroplating to form a conductive film (4). Figure 4B).

Furthermore, a metal electroplating layer (5) is formed on this by electroplating Ni (FIG. 4C).

Then, the metal plating layer (6) consisting of the conductive film (4) and the metal electroplating layer (4) is peeled off from the glass substrate (1) to produce a stamper (7) (FIG. 4D).

With the thus obtained stamper ()), for example, acrylic resin, polycarbonate resin, etc. are molded to form concave portions (8), that is, information pits, formed by the concave and convex surface of the reverse pattern onto which the concave and convex surface of the stamper (5) is transferred. A formed optical disc (9) is obtained (FIG. 4E).

However, the information recording surface of the optical disc (7) obtained in this way, that is, the uneven surface of the stamper (5) is
As is clear from Figure C, most of it is resist (2)
The surface of this resist (2) is not smooth and concave, which poses a problem as an optical surface. ), and as the pitch and size of information pits become smaller with higher recording densities, problems arise not only in surface properties but also in recording and playback characteristics. Problems arise.

In order to solve the problem of the surface properties of the resist (2), as shown in FIG. 12) is applied over the entire surface, and is exposed and developed to form a resist (2) having a desired pattern of openings (3) (FIG. 5A).

Using this resist (2) as an etching resist, the surface (1a) of the glass substrate (1) is etched through the opening (3) by RIE (reactive ion etching) or by chemical etching with hydrofluoric acid to form the recess (8), i.e. Information pits are formed (Figure 5B).

By removing the resist (2), an optical disc (9) having information pits (recesses) (8) is formed (fifth
Figure C).

However, in practice, the resist (2) obtained by coating the photoresist on the glass substrate (1) in this way has a problem in adhesion to the glass substrate (1), and this is used as a mask to coat the glass substrate (1). ) Recess (8) obtained by etching
That is, there is a problem in that the accuracy of the shape and size of the information pits is reduced, and there is a problem in increasing the density.

Furthermore, manufacturing the optical disks (9) one by one through the steps shown in FIG. 5 in this way has extremely low productivity. Therefore, using the glass substrate (1) obtained in FIG. 5C as a plating master, a metal plating layer (6) was formed on it with the same dimensions as explained in FIG. 4B-D, and this was applied to the glass substrate (
It is conceivable to prepare a stamper for obtaining an optical disk by peeling from 1). However, in practice, it is difficult to form a conductive film (4) on the glass surface by electroless plating, sputtering, etc. of Ni, or to form an electroplated layer (5) on this because of the adhesion between the glass surface and Ni. Since the Ni layer is weak, the stress during electroless plating, sputtering, and electric polishing causes the Ni layer to peel off, resulting in a decrease in precision.

Therefore, in forming this Ni layer, the glass substrate (1)
Methods such as roughening the surface to which the Ni layer is adhered with hydrofluoric acid, etc., or baking ceramics on the surface are used, but reducing the surface roughness in this way
This impairs the specularity of the uneven surface of the stamper obtained by peeling off the metal layer, resulting in deterioration of the characteristics of the information recording optical surface.

[Problem to be solved by the invention]

The present invention provides a method for producing an optical disc stand bar that can reliably produce a high-density optical disc.

[Means to solve the problem]

The present invention involves a step of treating a glass substrate surface with a coupling agent having a hydrophilic group on at least one of metal atoms such as Si or Ti and a lipophilic group on the other, and coating a photoresist on the glass substrate surface. a step of exposing and developing the photoresist in a desired pattern to form an opening; a step of using the photoresist as an etching resist and etching the surface of the glass substrate through the opening to form a recess; A step of removing the metal, a step of applying metal plating to the surface of the glass substrate including the inside of the recess, and a step of peeling off the metal plating from the surface of the glass substrate.
Or make a metal mask to obtain a stamper.

Further, in the present invention, before applying metal plating to the above-mentioned glass substrate surface, the glass substrate surface, including the inside of the recess, is cleaned and treated with the same coupling agent as described above.

[Effect]

In the manufacturing method of the present invention described above, a recess is formed in the glass substrate,
A metal plating layer is formed on this, and this is peeled off to form a stamper or a master used to obtain a stamper, so the uneven surface of the stamper for forming information pits has excellent surface properties. have

Then, since the photoresist for forming the recesses in the glass substrate is applied to the surface of the glass substrate treated with the coupling agent, it is possible to form the recesses with excellent adhesion.
RIE this onto the glass substrate surface as an etching resist.
, or by chemical etching. The recess is
Can be formed with high precision. Therefore, the stamper 1 formed using this as a plating master and the optical disk obtained thereby can be formed with high precision as an excellent optical information surface.

Furthermore, by using the glass substrate with the above-mentioned recesses as a plating master and treating it with a silane coupling agent to form a metal plating layer, for example, this metal plating layer can be made into a conductive film by electroless plating (chemical plating). When formed by electroplating on top of this, it is possible to obtain adhesion to the extent that peeling does not occur due to the stress, and furthermore, this metal plating layer can be easily peeled off from the glass substrate surface. As a result, we were able to obtain a highly accurate stamper 1 or a metal master for obtaining a stamper.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

In this example, first, as shown in FIG. 1A, the surface (
The surface of the glass substrate (11), which has been polished to a smooth surface, is treated with a coupling agent. Then, on this glass substrate (11), the film thickness is λ/4n of the exposure wavelength for this.
(n: refractive index) or more, for example, 500 to 1,500 positive photosensitive resins, ie, positive photoresists (12), are applied.

As shown in FIG. 1B, the photoresist (12) is exposed in a pattern according to recorded information, for example, by laser beam irradiation, and as shown in FIG. form. At this time, the laser beam hν is adjusted so that the aperture axis W at the boundary with the glass substrate (11) becomes larger than the aperture radius W1 at the laser beam incident side end face of the aperture (13) after development of the photoresist (12). The energy and output are adjusted to selectively expose light according to the recorded information.

Note that the laser beam hν at this time is applied to the photoresist layer (
12) The spot diameter was set to 0.4μ on the surface.

In this way, an opening (13) with a trapezoidal cross section of W+ > Wz
form.

At this time, the opening width W2 of the opening (13) on the glass substrate (11) side was 0.4 mm or less.

Next, using the photoresist (12) having the opening (13) as an etching mask, the surface (ll) of the glass substrate (11) is
A) is etched to a depth of, for example, λ/4n of the wavelength λ of light used for recording and reproduction on the optical disc to be finally obtained, thereby forming a recessed portion.

As a result, as shown in the first diagram, the opening width W of the recess (14) is the width W of the opening (13) of the photoresist (11).
It is formed with a width corresponding to 2.

Next, the photomask is removed, washed, and the surface of the glass substrate (11) including the inside of the recess (14) is again treated with a coupling agent.

Thereafter, a mother, a stamper, etc. are prepared according to ordinary optical disk manufacturing techniques to produce an optical disk.

For example, the glass substrate (11) having the recesses (14) obtained as described above is used as a plating master plate, and as shown in FIG. After that, a conductive film (15) is formed by electroless plating (chemical plating) or sputtering with Ni, and on top of this, for example, N is applied.
Electroplating (16) of i is formed to form a metal plating layer (17) having the required strength.

Next, as shown in FIG. 1F, the plating layer (17) is peeled off from the glass substrate (11) to produce a stamper or a metal mask for forming a stamper. This peeled stamper or metal mask (18) has
Pit or recess (14) formed in the base (11)
A convex portion (19) to which is transferred is formed.

Next, when this is used as a metal mask, a mother (20) is transferred and produced using this metal mask (18), as shown in FIG. 1F.

As a result, this mother (20) has a metal mask (1
The concave part (21) to which the convex part (19) formed in
) is formed.

Next, as shown in FIG. 1G, a stamper (22) is produced using a mother (20).

This stamper (22) is formed with a convex portion (23) to which the concave portion (21) formed on the mother (20) is transferred.

Next, as shown in FIG. 1H, the optical disk substrate (24) is stamped by pressing the stamper (22) onto, for example, acrylic resin or polycarbonate resin, or by using a mold.
Create.

This optical disk substrate (24) has a stamper (22).
A recess (25), that is, a pit, is formed corresponding to the protrusion (23) formed in the groove.

As shown in FIG. 1I, this optical disk (24) is formed with a reflective film (26) made of, for example, aluminum, including the inside of the recess (pit) (25).

Further, as shown in FIG. 1J, a protective film layer (27) made of resin or the like is formed on the reflective film (26) to complete a high-density optical disc.

The coupling agent used in the coupling agent treatment in the above-mentioned stamper manufacturing method has a hydrophilic group on at least one side and a lipophilic group on the other side of the metal atoms such as S1+ TI, that is, for example, an amino group, an epoxy group, etc. at the terminal. For example, a silane coupling agent and a titanium-based coupling agent can be used. As the silane coupling agent, for example, T-
(2-Aminoethyl)・Anomiprovir・Trimethoxy・Silane (NHzChCHJHCHzCI (zcHzs
i(OCH+)z) For example, ■East, Down Ender,
Product name 586020P manufactured by Silicone Co., Ltd. was used. The improvement of adhesion by such a coupling agent, such as a silane coupling agent, is due to the hydrolysis of ・Si (OCHs) to ・Si (OH) 3, which forms a hydrogen bond with 5i-OH on the glass surface, and further Si -0- by heating
This is due to the chemical bonding of 5i, which provides strong adhesion. The adhesion with the photoresist (12) is determined by the remaining hydrophobic groups (lipophilic groups), amino M (NH,-, -NH-).
This is due to the reaction of the resist with the resist. Furthermore, the adhesion with the chemical plating layer is due to the polarity of the amino group, which creates an affinity with the pretreatment such as palladium stannic acid colloid performed during chemical plating, resulting in appropriate adhesion and removability. Conceivable.

According to the above method, an etching mask made of photoresist (12) is formed on the glass substrate (11), and etching is performed through the opening (13) to form the recess (14).
), the slope of the side surface can be made smaller compared to the recess formed by the resist explained in FIG. 4C.
) is formed by anisotropic etching such as RIE, the recess (14
) can be formed.

In the above example, the stamper (22) is produced using the metal plating layer (17) as a metal mask, but it is also possible to mold an optical disc using the metal plating layer (17) itself as a stamper. .

In addition, in the above-described manufacturing method of the present invention, the formation of the metal plating layer (17) on the glass substrate (11) in which the recessed portion (14) obtained in the first drawing is formed, that is, the manufacture of the stamper or metal mask (18) is performed. Same glass substrate (11
) can be used repeatedly several times, in which case the glass substrate (11) as a plating master is cleaned and subjected to silane coupling treatment each time before plating treatment.

Furthermore, the pattern exposure of the above-mentioned photoresist (12) with laser light will be explained.

Normally, when the laser beam hv is focused and irradiated onto the photoresist layer (12) on the glass substrate (11), the laser beam hv
ν has a distribution as shown in FIG. 2A, and the intensity distribution of the laser beam hν at this time has a distribution shown by a dashed-dotted line a in the figure. The area exposed to a developable state under these conditions is the area surrounded by the broken line in the figure, that is, the shape corresponds to the intensity distribution of the laser beam hv.

Therefore, when this is developed, as shown in FIG. 2B, the opening (13) formed in the exposed part has an opening width W at the end face on the laser beam incident side that is at the boundary with the glass substrate (step 1). Opening width W! It is made larger and has a so-called trapezoidal cross-sectional shape.

Therefore, by changing the output of the laser beam having such intensity distribution characteristics, exposure can be performed in accordance with this output.

That is, as shown in FIG. 3A, the glass substrate (11)
Laser light h is applied to the photoresist (12) formed above in such a way that the output gradually decreases from left to right in the figure.
v,, hνz l hv3. The spot diameter of hv is
In both cases, the thickness is set to 0.4 μm on the surface of the resist (12).

Next, when the exposed resist layer (12) is developed, as shown in FIG. The opening width W0 is approximately the same width (0.4 μm) as the opening width W,2 at the boundary with the glass substrate (11). On the other hand, apertures (13b) and (13c) were formed by exposure while gradually weakening the output of the laser beam hv2゜hv3.
), the laser beam hv,.

Aperture width W b,, W, at the end surface on the incident side of hv3.

is the opening width Wh2 at the boundary with the glass substrate (11)
°Wc2 becomes smaller. For example, the laser beam hν2
Opening width W, , Wc at the end face on the incident side of °hv3.

is 0.4 μm, whereas the glass substrate (11)
The opening widths Wbt and Wc2 at the boundary between the two are 0.2 μm and 0.1 μm, respectively. On the other hand, the opening (13d) formed in the part exposed with the weakest output is the end surface on the incident side of the laser beam hν4 because the exposed area in a state where it can be developed by the laser beam hν4 does not reach the glass substrate (11). Although the opening width W41 is 0.4 μm, it is not opened on the glass substrate (11).

In this way, even if the spot diameter of the laser beam is made constant on the surface of the resist layer, the shape of the aperture formed by the laser beam varies depending on the output of the laser beam. By selecting the light output, it is possible to select the aperture width W2 of the aperture (13) on the glass substrate (11) side in FIG. Become.

〔Effect of the invention〕

As described above, according to the present invention, the recess shown in the first diagram (
Since the metal plating (17) is formed using the glass substrate (11) having a glass substrate (14) as a plating master, the final optical disc has a surface quality that follows the unevenness of the glass surface with excellent surface properties. Since it does not depend on the photoresist surface as mentioned at the beginning, optically excellent information bits can be formed.

In addition, by applying a coupling agent treatment such as a silane coupling agent to the glass substrate (11) as a plating master having the recesses (14) shown in the first diagram, good adhesion to the glass substrate (11) can be achieved. Furthermore, after the metal plating layer (F) is formed, it can be peeled off with appropriate releasability, and this glass substrate can be used repeatedly to obtain multiple stampers, making it possible to obtain a high-precision stamper.
can be mass-produced.

[Brief explanation of drawings]

FIG. 1 is a process diagram of an example of a method for manufacturing a stamper for an optical disk according to the present invention, FIGS. 2 and 3 are explanatory diagrams of the relationship between exposure of a photoresist and an aperture, and FIGS. 4 and 5 are Each is a process diagram of a conventional method. (11) is a glass substrate, (12) is a photoresist, (
17) is a metal plating layer. Figure 1 (Part 1) Figure 1 (Part 1) Figure 1 (Part 2) To the photoresist 11') The opening wheel is the name of the second figure, the name of the first light, and the tamper for the light! ! ! ! Sakuhiro's Energy Journey Figure 4 Figure 5

Claims (1)

[Claims] 1. A step of treating the surface of the glass substrate with a coupling agent having a hydrophilic group on at least one of the metal atoms and a lipophilic group on the other, and applying a photoresist to the surface of the glass substrate. a step of exposing and developing the photoresist in a desired pattern to form an opening; a step of etching the glass substrate surface through the opening using the photoresist as an etching resist to form a recess; An optical disc stamper comprising: removing a photoresist; applying metal plating to the surface of the glass substrate including the inside of the recess; and peeling off the metal plating from the surface of the glass substrate. How to make 2. In claim 1, before applying metal plating to the glass substrate surface, the glass substrate surface including the inside of the recess is cleaned, and at least one of the metal atoms has a hydrophilic group and the other has a hydrophilic group. A method for producing a stamper for an optical disc, the method comprising processing with a coupling agent having an oil base.