JPS59193560A - Stamper for rotary recording medium and its manufacture - Google Patents

Abstract

PURPOSE:To obtain easily a stamper having excellent performance by forming successively an information transfer layer consisting of a material having high surface hardness and an intermediate layer consisting of a metal by a vacuum film forming method then forming a backing layer by an electroforming method. CONSTITUTION:An information transfer layer 2 consisting of a material having high surface hardness is formed by a vacuum film forming method on a matrix 1 for duplication and further an information transfer layer and a backing layer 4 are adhered thereto. An intermediate layer 3 playing the role of permitting electroforming of the backing layer is thereafter formed by a vacuum film forming method thereon in the same vacuum vessel. The information transfer layer and the backing layer adhered by the intermediate layer are stripped from the matrix for duplication and a stamper is obtd. Cr, Cr-Co alloy, corundum, TiN, TiC and SiC are used for the information transfer layer and Fe, Ni, Cu and Sn are used for the intermediate layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stamper for a rotary recording medium and a method for manufacturing the same, and an object thereof is to easily obtain a stamper with excellent information transfer properties and a long life.

There is a rotating recording medium in which information signals are recorded on a plastic disk by forming minute irregularities, and then read and reproduced using an optical method.A typical example is an optical video disk. There are also digital audio discs. The signal of the fine irregularities of such a recording medium is obtained by a method of transferring the signal of the fine irregularities recorded on a stamper that is attached to a mold during molding of a plastic disk. A stamper is attached to the mold surface of a molding machine to form a signal surface of a disk, and is usually manufactured by electroforming as described below. That is, a thin film of resist or metal is formed on an optically completely flat glass disk, and this is processed using a laser or the like to form irregularities corresponding to information signals. The glass master disc thus obtained is used as a master mold and electroformed to obtain a so-called master disc with the unevenness reversed and transferred.

Since the master disk is usually not conductive, when electroforming the master disk, a conductive thin film is formed on the master disk by silver mirror reaction, vacuum evaporation, sputtering, etc., and then nickel electroforming is performed. If a plastic disk is molded using the master disk as it is as a stamper, the information signals on the master disk will be reproduced as they are on the plastic disk. The depth of the unevenness of the signal can usually be set to 1/2n (n is a positive integer) of the wavelength of the laser beam for reading. However, the surface of the master disk is a conductive coating on the master disk, which may not have enough strength to withstand repeated molding.Usually, the master disk is electroformed after being peeled off, and once the unevenness is reversed, it is called a mother disk. A disk is obtained, and this mother disk is further subjected to peeling treatment and electroforming to obtain a stamper.

However, since the surface of the stamper obtained by nickel electroforming from the mother disk is also made of nickel, the unevenness is gradually damaged by repeated molding, and the transfer of the relief-like information becomes inaccurate. Thus, nickel stampers usually have to be replaced after at most several thousand shots of injection molding. The surface of such a nickel stamper is plated with chrome to increase its surface hardness, which is commonly done in the case of audio record stampers. In the case of body stampers, if the information surface is chrome plated after being peeled off from the mother plate, the thickness of the plating is usually several microns or more, which is sufficient to increase the surface hardness. Since the information irregularities have submicron dimensions, the information surface is smoothed by plating, which has the drawback of making the information transfer inaccurate.

Attempts have already been made to form the information transfer layer of the Socote stamper itself from a material with high hardness. For example, JP-A-5
The method disclosed in Publication No. 7-103106 involves directly plating chromium on a nickel mother, electroforming nickel as a backing layer on top of it, and then peeling it off from the mother, so that the information transfer layer on the surface is made of chromium. I got a stamp. However, in this method, the surface layer made of chromium is quickly oxidized and becomes passivated, so it loses its adhesion to nickel, and peeling occurs between it and the nickel backing layer obtained by electroforming on top of it. The disadvantage is that it is easy to occur. Chromium is thus prone to form a surface oxide film, and it is difficult to remove the formed chromium surface oxide film by acid treatment, and it cannot be removed by diluted acid. Furthermore, if treated with concentrated strong acid, the chromium layer itself may crack and form pinholes, and removing only surface oxides without damaging the chromium layer requires delicate control of conditions and is extremely troublesome. . Furthermore, even if it is possible to remove the oxide film by applying an oxide film to the temporary Q, it is difficult to create a backing layer that will not peel off because there is a risk that the surface will be oxidized again during the next nickel electroforming operation. be.

In addition, in order to be able to create an information transfer layer by chromium plating, the matrix must be conductive, such as a nickel mother. This method cannot be applied to non-conducting materials such as molds.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 57-64508, a nitride, carbide, or oxide of a group 4 or 5 element, or a composite thereof, is applied as an ion plating film on the surface of the stamper. It has also been proposed to form In this case as well, these surface hardening layers are effective at 50 to 3000A, especially 100 to 1 soo It is clear that the transcription will be inaccurate.

The present invention is an improved method of forming the information transfer layer itself from a material with high hardness, which eliminates the drawbacks of the known methods as described above, provides excellent information transferability, and forms information reliefs by repeated molding. The present invention provides a stamper that exhibits little deterioration and has a long life.

That is, as a result of intensive studies, the present inventors have developed a stamper with superior performance as described above by applying the vacuum film forming method.
We found that it is easy to obtain.

That is, the present invention provides an information transfer layer made of a material with high surface hardness on a replication matrix carrying relief-like information, and a metal or silicone that is conductive and does not easily form an oxide film, or is easy to remove even if it does. An intermediate layer is sequentially formed using a vacuum film forming method, and then a binding layer is formed using an electroforming method, and the information transfer layer and backing layer adhered to the intermediate layer are peeled off from the matrix. A method for producing a stamper for a rotary recording medium, characterized in that it is obtained by the method, an information transfer layer made of a material with high surface hardness obtained by such a production method, and a backing layer,
A film is formed from an intermediate layer made of a metal that has conductivity to bond these two layers and is difficult to form an oxide film, or is easy to remove even if it is formed, and the thickness of the information transfer layer is 0.05 to 10 μm.
This invention relates to a stamper for a rotary recording medium in which the intermediate layer has a thickness of 0.05 to 10 μm and the backing layer has a thickness of 0.1 to 1.0 μm.

The present invention will be explained below with reference to the drawings.

In the present invention, as shown in FIG. 1, an information transfer layer (2) made of a material with high surface hardness is formed by a vacuum film forming method on a replication master mold (1) having relief-like information. Furthermore, an intermediate layer (3) serves to bond the information transfer layer and the backing layer (4) and to enable electroforming of the backing layer.
) is subsequently formed on the information transfer layer by a vacuum film forming method in the same vacuum container. The vacuum film forming method may be any method as long as it can be deposited under vacuum, and specific examples include vacuum evaporation, sputtering, and ion blating. A backing layer is formed by electroforming, and the information transfer layer and backing layer adhered to the intermediate layer are peeled off from the duplication mold to obtain a stamper (FIG. 2).

The replica matrix carrying relief-like information can be manufactured using materials such as glass, plastic, and metal.

The information transfer layer must be made of a material with high surface hardness.
'Or, 0r-Co alloy, silundum, TiN.

An example is Ti0,810. In order to enable the electroforming of the backing layer, the intermediate layer is made of a metal that has conductivity and is easy to remove even if an oxide film is formed to prevent separation from the electroformed backing layer. Otherwise, Fe.

Examples include Ni, Ou, and Sn. According to the present invention, since the information transfer layer (first layer) and the intermediate layer (second layer) are formed on the replica matrix in vacuum by the vacuum film forming method, unlike the conventional electrolytic plating method, the first layer Even if the metal is not conductive, a second layer can be laminated thereon, and if the first layer is a metal such as Cr that easily forms an oxide film, the second layer may peel off depending on the electroforming method. Even in cases where the second layer is easy to adhere to, the second layer can be formed on the first layer with good adhesion by the vacuum film forming method.

According to the invention, the backing layer is formed on the intermediate layer by electroforming. The metal that is electroformed is usually a stamper.
For the buttons used, metal materials with sufficient mechanical strength are chosen, for example nickel or copper. For electroforming, a known method using a nickel sulfamate bath, a copper pyrophosphate bath, or the like may be used. When performing electroforming, it is desirable to perform electroforming immediately after vacuum film formation to prevent oxidation of the second layer, and to perform a pretreatment to remove the oxide film.

Thus, in the stand bar obtained according to the present invention, an information transfer layer with high surface hardness is formed directly on the replication matrix, so that
The signals of the irregularities of the mother mold are clearly and accurately transferred, and the transferred signals are not easily deteriorated even by repeated molding of plastic. Furthermore, the highly hard information transfer layer and backing layer are adhered to the intermediate layer with good adhesiveness and will not peel off.

The present invention will be explained below with reference to examples.

Example: A positive resist AZ135 from 5hiple7 was placed on a mirror-polished glass disc with a diameter of 556+1+m and a thickness of 6m.
0 evenly coated with a spin coater to a thickness of 700A,
Width 0.8μ by Ar laser beam with narrowed beam diameter.
After spiral exposure with a pitch of 2.5 μm, development was performed to obtain a master disc having grooves of 700 A in depth, 0.8 μ in width, and 2.5 μ in pitch. Films of chromium and nickel were sequentially formed on the master disc with a diameter of about 100 OA each using a magnetron sputtering device having two targets of chromium and nickel. By sputtering chromium and immediately sputtering nickel without breaking the vacuum, an oxide layer is formed between the chromium layer (information transfer layer) and the nickel layer (intermediate layer) above it. The two were laminated with good adhesion.

The master whose surface is covered with such a nickel layer is immediately
After treatment with a sulfaonic acid solution by weight, nickel sulfamate (tetrahydrate) 400 f/l, nickel chloride (hexahydrate) 5 ? /L, 5oy7t of halonic acid
.

Bit inhibitor 0.5? /l, and rotated facing the anode box containing the electrolytic nickel pellets while maintaining an angle of 45° to the vertical plane.
Electroforming was performed at 0° C. by applying current for 227 ihr.

Thereafter, the electroformed product was peeled off from the master to obtain a stambar with a thickness of 0.3 mm on which the grooves of the master were reversely transferred.

The thus obtained stambar was 527 mm in diameter.

It was used for injection molding of a polymethyl methacrylate resin disk with a thickness of 1.2 mm, and after 10,000 shots of molding, the groove shape transferred to the disk was examined using a thin film profilometer, and it was found that approximately 500 shots of the disk and approximately - No significant difference in groove shape was observed in the 10,000th disk.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a state in which a stub bar is formed on a relief-like duplication master mold, and FIG. 2 is a cross-sectional view showing a stub bar peeled off from the mother mold. 1...Replication matrix, 2...Information transfer layer, 3...Intermediate layer, 4...Backing layer Applicant's agent Kaoru Furuya 1 Figure/-4 Figure 2 12222 -----Ninini=-Ninini-2=~3--L
l 2

Claims (1)

[Scope of Claims] 1. An information transfer layer made of a material with high surface hardness, a backing layer, and a backing layer that has conductivity to bond these two layers and that is difficult to form an oxide film or is easy to remove even if it is formed. Formed from an intermediate layer made of metal, the thickness of the information transfer layer is 0.05
~10μ, intermediate layer thickness 0.05~10μ, backing layer thickness 0.1~1.0m+ll Stamper 0 for rotary recording media 2. Substances with high surface hardness include chromium, chromium-cobalt alloy, corundum. , titanium nitride, titanium carbide or silicon carbide, the backing layer is not made of nickel or copper, and the metal of the intermediate layer is iron-nickel, copper or tin. -0 3 An information transfer layer made of a substance with high surface hardness on the replication matrix carrying relief-like information, and an intermediate layer made of a metal that has conductivity and is difficult to form an oxide film, or is easy to remove even if it is formed. Multiple layers are sequentially formed by a vacuum film forming method, then a backing layer is formed by an electroforming method, and the information transfer layer and the backing layer adhered by the intermediate layer are peeled from the matrix. A method for manufacturing a stamper for a rotary recording medium, characterized by: 4. The material with high surface hardness is chromium, chromium-cobalt alloy, corundum, titanium nitride, titanium carbide, or silicon carbide, the backing layer is not nickel or copper, and the intermediate layer metal is iron, nickel, copper, or tin. A method for manufacturing a stamper for a rotary recording medium according to claim 3.