JPH04229211A - Manufacture of stamper - Google Patents

Abstract

PURPOSE:To enable a high precise stamper to be produced, while an electrically conductive film is not separated from a glass-substrate and the stamper may be released from a master matrix by a method in which the electrically conductive film composed of two layers is formed by laminating a tantalum-thin film and a nickel-thin film in order along the surface of uneven pattern, and nickel is treated into passive state. CONSTITUTION:The thin film of tantalum is formed by means of spattering, and the thickness of the thin film of tantalum is about 300Angstrom . Next, the thin film 4 of nickel is formed by means of spattering, and the thickness of which is about 300Angstrom . Then the base plate is dipped in the aqueous solution of potassium bichromate of 5wt.% for one minute, and the nickel film in passive state is formed on the surface of the nickel-thin film, and then the master matrix for producing a stamper is made.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a stamper. It is especially used in the production of plastic substrates for optical discs.

0002

2. Description of the Related Art A conventional method for manufacturing a stamper used for injection molding of substrates for magneto-optical disks and write-once optical disks is as follows.

First, as shown in FIGS. 2(a) to 2(c), a photoresist 2 is coated on a glass substrate 1, cut with a laser beam 7, and then developed to form a resist pattern 2a in a desired shape. form.

Next, as shown in FIGS. 2(d) to 2(e), a nickel conductive film 4 is formed on the surface on which the resist pattern 2a is formed by sputtering, vapor deposition, etc., and electroforming is performed to form a nickel conductive film 4. A cast film 5 is formed to a desired thickness. After that, the nickel conductive film 4 is peeled off from the glass substrate 1, and the nickel conductive film 4 is peeled off from the glass substrate 1.
) as the stamper 6.

[0005] In the conventional stamper manufacturing method described above, the master master has the photoresist pattern as it is.

000
6] To create fine pattern shapes with high precision, it is necessary to apply photoresist uniformly and with good reproducibility.
spinner rotation speed, etc.), coating environment (environmental temperature, humidity, etc.)
, development conditions (developer temperature, amount of liquid dropped, etc.), manufacturing conditions, and process control must be thoroughly controlled.

When the master master disc and the conductive film are peeled off, the photoresist remains on the conductive film side, so a process is required to remove this residual photoresist. Removal of residual photoresist may be insufficient using the dry ash method or removal method using photoresist stripper.
There was a risk that the quality of the stamper would deteriorate.

[0008] In order to solve the above-mentioned problems,
As a master master, a glass substrate in which a concavo-convex pattern is directly formed by sputter etching, ion etching, or plasma etching is used. FIG. 3 shows a general method for manufacturing this type of stamper. First, as shown in FIGS. 3A to 3C, a photoresist 2 is applied to a glass substrate 1, cut with a laser beam 7, and then developed to form a resist pattern 2a in a desired shape. Next, as shown in FIGS. 3(d) to (e), using the resist pattern 2a as a mask, the glass substrate 1 is etched into a predetermined pattern by sputter etching, ion etching, plasma etching, etc., and the photoresist is removed. Obtain the master master disc. Furthermore, as shown in FIGS. 3(f) to 3(g), a nickel conductive film 4 is formed on the glass substrate 1 etched in a predetermined pattern by a method such as sputtering or vapor deposition, and an electroforming process is performed to form nickel. The film 5 is formed to a desired thickness. After that, the nickel electroformed film 5 is peeled off from the glass substrate 1 as shown in FIG. 3(h).
Assume that the stamper 6 is as follows.

[0009]

[Problems to be Solved by the Invention] As mentioned above, when using a glass material with an uneven pattern directly formed by sputter etching, ion etching, or plasma etching as a master master, it is difficult to use it as a conductive film for electroforming. A nickel film is formed by sputtering, vapor deposition, or other means. However, this nickel film has poor adhesion to quartz glass and soda glass, which are commonly used as glass substrates.
In particular, when quartz glass is used as a substrate, there is a large difference in coefficient of linear expansion, resulting in very poor adhesion to the nickel film, resulting in the problem that the nickel film peels off from the glass substrate during electroforming. The present invention was made in order to solve the above problem, and provides a method for manufacturing a stamper that can be released from a master master without the conductive film peeling off from the glass substrate, and that can manufacture a highly accurate stamper. This is what I am trying to do.

0010

[Means for Solving the Problems] According to the present invention, a predetermined uneven pattern is formed on the surface of a flat quartz or glass substrate by photolithography,
A tantalum thin film and a nickel thin film are sequentially laminated along the surface of this uneven pattern to form a two-layer conductive film,
A master master having a concavo-convex pattern of a conductive film covered with a nickel passivation film is prepared by applying nickel passivation treatment, and a nickel electroformed layer is applied onto this pattern surface until at least the concavo-convex pattern is embedded by electroforming. A method for manufacturing a stamper is provided, which comprises forming a nickel electroformed layer and releasing the nickel electroformed layer from a master master, thereby manufacturing a nickel stamper having an uneven surface.

In the present invention, a predetermined uneven pattern is formed on the surface of a flat quartz or glass substrate by photolithography. The quartz or glass substrate is used to constitute a master master for stamper production, and has a surface roughness of usually Rmax5.
It can be manufactured by performing a surface flattening process to obtain a thickness of angstroms to 20 angstroms. The above uneven pattern is an inverted pattern in which the dimensions of the recesses are larger than the unevenness on the surface of the stamper to be manufactured, corresponding to the thickness of the conductive film (tantalum thin film and nickel thin film (surface passive)), which will be described later. Can be used. The uneven pattern can be formed by, for example, coating a photoresist on the quartz or glass substrate to form a photoresist film, cutting with laser light and developing to form a photoresist pattern, and using this resist pattern as a mask. For example, the quartz or glass substrate can be etched by sputter etching, ion etching, plasma etching, or the like.

In the present invention, a tantalum thin film and a nickel thin film are sequentially laminated along the surface of the uneven pattern to form a two-layer conductive film, and a nickel passivation treatment is performed to form a nickel passivation film. A master master disc having a concavo-convex pattern of a conductive film coated with is prepared. The tantalum thin film is used to form a conductive film for electroforming and to prevent peeling of the nickel thin film formed along the surface of the uneven pattern of the upper quartz or glass substrate. It is used by first forming it along the surface of a concavo-convex pattern on a quartz or glass substrate. This formation is performed, for example, by a sputtering method, a vapor deposition method, or the like. This film thickness is usually 100 to 400 angstroms. The nickel thin film constitutes a conductive film for electroforming and also forms a nickel passive film, and is used by being formed on the tantalum thin film along the surface of the uneven pattern. This formation is performed by, for example, a sputtering method, a vapor deposition method, or the like. This film thickness is usually 200 to 500 angstroms. The nickel passive film is for releasing the nickel electroformed film deposited thereon from the master master, and is made of quartz or glass on which a tantalum thin film and a nickel thin film are sequentially formed along an uneven pattern. It can be formed and used by subjecting a substrate to treatment such as immersion treatment in an aqueous potassium dichromate solution or oxygen plasma treatment. For example, in the potassium dichromate aqueous solution immersion treatment, 5 wt%
This can be done by immersing the substrate in a potassium dichromate aqueous solution for 1 minute. The oxygen plasma treatment can be performed, for example, by treating the substrate at an oxygen gas pressure of 6 mm Torr and a power of 150 W for 3 minutes.

In the present invention, a nickel electroformed layer is formed on this surface by electroforming until at least the uneven pattern is embedded, and the electroformed layer is released from the master master using the nickel, thereby forming the uneven surface. A nickel stamper having the following properties is manufactured. In addition, the master master disc is
Since the nickel passivation film is easily damaged during mold release and post-mold cleaning processes, each time the mold is released, the substrate is cleaned with, for example, a nitric acid aqueous solution to dissolve and remove the nickel thin film with the nickel passivation film, and the nickel thin film with the nickel passivation film is removed again. It is preferable to renew the nickel passivation film by forming a nickel thin film and passivating it. The concentration of the nitric acid aqueous solution is usually about 20 wt%.

[0014]

[Operation] The tantalum thin film is interposed between the quartz or glass substrate and the nickel thin film, and adheres well to both the substrate and the nickel thin film. The nickel passivation film reduces the adhesion with the nickel electroformed film, making it easier to release the nickel electroformed layer (stamper) from the master master.

[0015]

[Embodiment] An embodiment of the present invention will be explained with reference to the drawings.

Example 1 First, as shown in FIGS. 1(a) to 1(c), a photoresist 2 is coated on a glass substrate 1, cut with a laser beam 7, and then developed to form a desired shape. A resist pattern 2a is formed. Next, Figures 1(d) to (e)
), using the resist pattern 2a as a mask, the glass substrate 1 is etched into a predetermined pattern by sputter etching, and then the resist pattern 2a is removed.

Next, as shown in FIG. 1(f), a tantalum thin film 3 is formed by sputtering. The thickness of the tantalum film is approximately 300 angstroms. Next, Figure 1
As shown in (g), a nickel thin film 4 is formed by sputtering. The thickness of the nickel thin film forming the nickel thin film 4 is approximately 300 angstroms. Thereafter, this substrate is immersed in a 5% by weight aqueous solution of potassium dichromate for 1 minute to form a nickel passivation film on the surface of the nickel thin film, thereby producing a master master for stamper production.

Next, as shown in FIG. 1(h), electroforming is performed on this master master to form a nickel electroformed layer 5 of 0.3
It is formed with a thickness of mm. Thereafter, only the nickel electroformed layer is peeled off to form a stamper 6 as shown in FIG. 1(i).

Example 2 A case will be described in which the master disc used in Example 1 is reused.

[0020] Since the nickel passivation film of the master master disc that has been used may be damaged during the cleaning process during electroforming film removal, the nickel passivation film and nickel thin film are removed by cleaning with nitric acid. do.

[0021] The concentration of nitric acid is 20 wt%. After this, a nickel thin film and a nickel passivation film are formed in the same process as in Example 1, a master master is produced, and a stamper is produced.

The obtained stamper is of good quality with no deterioration of the S/N ratio because the nickel passivation film of the master master on which the signal surface of the stamper is formed is renewed each time it is used. It can be obtained repeatedly from a master master disc.

[0023]

According to the present invention, the nickel electroformed layer can be peeled off from the master master without peeling off the conductive film on the surface of the master, and a high-quality stamper without deterioration of the S/N ratio can be obtained. It is possible to provide a method for manufacturing a stamper that can be repeatedly obtained from a single master disc.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a method for manufacturing a stamper produced in an example of the present invention,

FIG. 2 is an explanatory diagram of a conventional stamper manufacturing method.

FIG. 3 is an explanatory diagram of a conventional stamper manufacturing method.

[Explanation of symbols]

1 Glass substrate, 2a　Uneven pattern, 3 Tantalum thin film, 4 Nickel thin film, 5 Nickel electroformed layer, 6 Stamper, 7 Laser light.

Claims (1)

[Claims] [Claim 1] On the surface of a flat quartz or glass substrate,
A predetermined uneven pattern is formed by etching using photolithography, a tantalum thin film and a nickel thin film are sequentially laminated along the surface of this uneven pattern to form a two-layer conductive film, and nickel passivation treatment is performed. A master master having an uneven pattern of a conductive film covered with a nickel passivation film is prepared by applying a nickel passivation film, and a nickel electroformed layer is formed on this pattern surface by electroforming treatment until at least the uneven pattern is embedded. A method for producing a stamper, comprising producing a nickel stamper having an uneven surface by releasing an electroformed layer from a master master.