JPH0118996B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention is directed to the polishing plate of a plate-shaped body having unevenness information, such as a tip polishing plate of a stylus for a video disk, an optical disk memory, or a grooved capacitive video disk. This invention relates to a method for manufacturing a metal matrix for accurately replicating a concavo-convex information pattern.

[Prior art]

The reproduction of the uneven information pattern currently practiced is carried out using a reproduction technique substantially similar to that used in the production of phonograph records.

In other words, the duplication method used to produce phonograph records involves cutting sound grooves into the nitrocellulose lacquer surface using a vibrating cutting needle to record the sound as a so-called uneven pattern, and then applying a nickel coating to this recording master. Create a metal matrix by depositing
A record disc is produced by press-casting a suitable plastic material onto this metal matrix.

Similar to this duplication technique, the uneven pattern of a video disc, optical disc memory, or grooved capacitive video disc stylus tip polishing plate, etc. can be reproduced by photolithography on a glass master. A concavo-convex information pattern is formed on the surface of the resin, and a recording master plate is created by transferring this onto a suitable resin surface.
A metal matrix is made by applying a nickel film to this recording master, and a suitable plastic material is press-cast onto this metal matrix to reproduce the uneven information pattern.

Usually, as a pretreatment for applying a nickel film, the surface of the recording master is appropriately activated, and then a thin film of silver is deposited on the surface of the recording master by a chemical reduction method to form a conductive base layer. Then, after electroplating nickel onto this base layer to form a nickel layer of appropriate thickness, the structure is separated at the interface between the silver layer and the lacquer base layer to form a metal master mold.

In this method of manufacturing a metal matrix, it is usually necessary to coat the surface of the silver layer with nickel and/or chromium in order to harden the surface of the silver layer. Alternatively, the silver layer was etched away to expose the hard nickel surface.

Since the surface of the metal matrix is hardened in this way, it is not possible to completely and faithfully reproduce the uneven information pattern of the recording master, which has the drawback of causing some deterioration of the original recording. .

In order to solve this drawback, it has been considered to deposit a metal such as nickel on the surface of the recording original plate instead of the silver layer to form a conductive base layer.

However, this vapor deposition method is effective when the unevenness of the pattern is small, but in the case of general patterns with deep grooves, deep pits, or high protrusions, the metal film may not adhere to the sides of the deep grooves, deep pits, or high protrusions. As a result, wire breakage may occur during electroplating in the next step, resulting in inaccurate side profile, which also has the disadvantage that the uneven information pattern of the recording original plate cannot be completely and faithfully reproduced.

It is now known that the above-mentioned disadvantages of the prior art can be overcome by forming the conductive base layer for electrolytic plating by electroless plating of nickel or cobalt at about room temperature.

For example, the method disclosed in Japanese Patent Publication No. 49-47615 can be adopted.

However, this method, ie electroless plating of nickel or cobalt at about room temperature, is effective only when the adherend is a synthetic resin positive photoresist material in a form that is easily attacked by alkaline media. When applying the conventionally known hydrophilization method using chromic acid to hydrophilize the adherend, there is a technical problem in that electroless plating cannot be completed unless the chromium is completely washed away. There are many problems.

In particular, it is nearly impossible to completely remove chromium from fine pattern areas, so it is inappropriate to use this method to form a conductive base layer on a recording original.

Even if a hydrophilic treatment by immersion in an acid solution such as nitric acid is adopted as another hydrophilic treatment, the effect is insufficient and there is a problem of poor reliability.

In addition, the above-mentioned electroless plating method generates large plating stress, so that the deposited metal film is likely to crack and peel off during electroless plating or during the next process of electrolytic plating, resulting in pattern irregularities. There is a problem.

Furthermore, if a conductive base layer formed by electroless plating is kept in water, there is a technical problem in that pattern distortion is likely to occur.

[Purpose of the invention]

In order to solve the technical problems of the electroless plating method described above, the inventors conducted repeated experimental research, and as a result, the adherend was considered to be a negative photoresist instead of the conventional positive photoresist material. By using an ultraviolet curable resin and making it hydrophilic through plasma oxidation, electroless plating can be performed completely. By performing the processing appropriately, all the conventional technical problems could be solved.

An object of the present invention is to eliminate the conventional technical problems as described above and to provide a method for manufacturing a metal master mold for reproduction, which can accurately transfer the uneven information pattern of a recording master.

[Summary of the invention]

That is, in the present invention, the surface of an ultraviolet curable resin, which is a negative photoresist onto which a concavo-convex information pattern formed on the surface of a hard plate-like object such as glass is transferred, is subjected to a hydrophilic treatment using a plasma oxidation method, and then After cleaning this using a neutral detergent or a weak alkaline detergent, sensitization is performed to form active metal nuclei on the surface, and then nickel or cobalt is electrolessly applied to the activated surface at about room temperature. Then, a conductive base layer for electrolytic plating is prepared, and then nickel electrolytic plating is performed on the surface of the conductive base layer for electrolytic plating to form a metal body, and the metal body is bonded with the activated surface. It is characterized by separating at the interface between the two to form a metal matrix.

In carrying out the present invention, the thickness of the conductive base layer for electrolytic plating is between 400 Å and 2000 Å to prevent peeling of the deposited metal film due to plating stress of electroless plating. In addition, it is possible to improve the conductivity during electrolytic plating and to stabilize the adhesion of the adherend by heating and drying the adherend after electroless plating. Further, as the ultraviolet curing resin, an organic material having a carbon-carbon double bond can be used.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below. First, a concavo-convex information pattern is formed on a glass master by photolithography, and this is transferred to the surface of an ultraviolet curing resin to form a recording master.

Next, this recording master plate is subjected to a hydrophilic treatment for an adherend by a plasma oxidation method. This plasma oxidation method uses a dedicated plasma oxidation device or
This can be done by reusing an RF sputtering device.

The conditions for the plasma oxidation method at this time are moderate oxygen partial pressure of 0.2 to 0.8 T _prr and FR power of 50 to 200 W and processing time of 2 to 10 minutes.

In this way, after plasma oxidation treatment, cleaning with a neutral detergent or weak alkaline detergent, and then effective sensitization and activation treatment, forms active metal nuclei on the activated surface. .

The activated surface is then electrolessly plated with nickel or cobalt at about room temperature to form a conductive base layer for electrolytic plating. The thickness of the conductive base layer for electrolytic plating at this time is 400 Å to 2000 Å.

After the metal film of the conductive base layer for electroplating thus deposited is heated and dried by heated air blowing, the surface oxide film is removed using a dilute sulfuric acid solution or the like.

Nickel electroplating is performed on the conductive base layer for electrolytic plating from which the surface oxide film has been removed in this way to form a metal body, and this metal body is used at the interface between the activated surface and the recording layer. Separated from the original plate, the metal matrix is completed.

In the above metal matrix manufacturing method, a recording master is created using an ultraviolet curable resin, which is a negative photoresist, and the adherend is made hydrophilic using a plasma oxidation method. It was confirmed that electroless plating can be performed reliably even with patterns.

Furthermore, as a result of performing this plasma oxidation treatment under the conditions of oxygen partial pressure of 0.2T _prr , RF power of 50W, and treatment time of approximately 2 minutes, it was confirmed that effective hydrophilic treatment could not be performed under these conditions, and the above It was determined that each condition must be met or higher. In addition, it was confirmed that using an oxygen partial pressure of 0.8 T _prr , an RF power of 200 W, and a processing time of about 10 minutes or more damaged the pattern on the recording master. 0.8T _prr RF power 50~
It was confirmed that 200W and a processing time of 2 to 10 minutes are optimal.

In addition, it was confirmed that the maximum thickness for electroless plating at which peeling of the deposited metal film does not occur during electroless plating and post-process electrolytic plating is 2000 Å. On the other hand, it has been confirmed that a thickness of 400 Å is required for conductivity during electrolytic plating, and in the end, the thickness of electroless plating is 400 Å ~ 400 Å.
It was found that 2000Å is optimal.

Furthermore, when the deposited metal film formed by the electroless plating method was once heated and dried, a conductive film that adhered accurately to the pattern was obtained, and it was found that the pattern was extremely effective without causing any irregularities. Ivy.

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

Example 1 A pattern in which grooves with a depth of 5 μm and a width of 3 μm were carved in a spiral pattern at a pitch of 10 μm from a position of radius 3 cm to a position of 14 cm was formed on a glass master disk using, for example, polyethylene glycol diacrylate of the chemical structural formula (1). An ultraviolet curable resin obtained by adding, for example, benzoin isopropyl ether as a photopolymerization initiator to 1,6-hexanediol dimethacrylate of chemical structural formula (2) or a mixture thereof was used to transfer it onto a polymethyl methacrylate substrate carrier. This was made hydrophilic by an oxygen plasma method. The processing conditions at this time are oxygen partial pressure 0.2~
0.4T _prr , RF power of 50 to 100W, processing time of 2 to 10 minutes. After the oxygen plasma treatment, it was washed with a weak alkaline detergent, immersed in a tin chloride sensitizing solution, and immersed in a palladium chloride activation solution. Next, it was immersed in a room temperature nickel-boron type electroless plating bath to form a conductive base layer for electrolytic plating. The plating bath used for this purpose is a nickel plating solution containing nickel sulfate, a complexing agent sodium oxycarboxylate such as sodium citrate, and a reducing agent sodium hypophosphite, and the liquid temperature is 25°C. The treatment was carried out for 4 minutes, and a film thickness of approximately 1000 Å was deposited. Thereafter, it was washed in water, taken out, and dried using a hair dryer. The resistance of the pattern between the inner and outer circumferences at this time was about 50Ω. This was immersed in a 5% sulfuric acid aqueous solution to remove the surface oxide film, and then electrolytically plated with nickel in a nickel sulfamic acid bath. Nickel was deposited to a depth of 0.25 mm under conditions of bath temperature of 30°C, pH of 4.0, and initial current density of 0.1 A/dm ² . When the nickel surface was separated from the resin surface and the groove shape was observed, it was found that grooves that accurately corresponded to the groove shape of the glass master disk were obtained.

Example 2 From an optical disk video record master disk in which information pits and guide grooves were formed on a glass substrate from a radius of 3 cm to a position of 14 cm, an information pattern was formed on a glass substrate carrier using the same ultraviolet curing resin as in Experimental Example 1. was transcribed. This was subjected to hydrophilic treatment, sensitization treatment, and activation treatment in the same manner as in Experimental Example 1. Next, it was immersed in a room temperature electroless nickel plating solution (solution temperature 30°C) for 3 minutes to form a film with a thickness of about 600 Å. The composition of the room temperature electroless plating solution is as follows.

N _a4 P ₂ O ₇・10H ₂ O 12g/ C ₀ SO ₄・7H ₂ O 9.1g/ NH ₄ OH (58wt% liquid) 1.3cc/ (CH ₃ ) ₂ NHBH ₃ 0.3g/ Electroless plating method The formed conductive base layer was dried in the same manner as in Experimental Example 1. The resistance between the inner and outer circumferences of the pattern was about 100Ω. Next, electrolytic plating was performed in the same manner as in Experimental Example 1, the cobalt surface was separated from the resin surface, and the information pattern shape was observed, and an information pattern that accurately corresponded to the information pattern shape of the glass master disk was obtained.

〔Effect of the invention〕

As detailed above, according to the method of manufacturing a metal master mold for replicating a plate-like body having uneven information according to the present invention, an ultraviolet curable resin, which is a negative photoresist, is used as a recording master, and this is coated with a plasma oxidation method. Since the adherend is subjected to hydrophilic treatment, electroless plating can be performed completely even with a fine pattern, and a conductive base layer for electrolytic plating can be reliably formed. In addition, by heating and drying this conductive base layer for electrolytic plating, a conductive film that adheres accurately to the pattern can be obtained, and by making the adhesion thickness between 400 Å and 2000 Å, it is easy to use when performing electroless plating. This prevents peeling due to the plating stress that occurs and enables good plating without pattern irregularities.

By performing electrolytic plating on a good conductive base layer for electrolytic plating in this manner, it was possible to obtain a metal matrix that completely and faithfully corresponded to the pattern of the master.

Claims (1)

[Claims] 1. The surface of an ultraviolet curable resin onto which a concave-convex information pattern formed on the surface of a hard plate is transferred is made hydrophilic by a plasma oxidation method, then washed, and then enlarged. The activated surface is sensitized to form active metal nuclei, and then nickel or cobalt is electrolessly plated on the activated surface at approximately room temperature to form a conductive base layer for electrolytic plating, and further for electrolytic plating. A metal body is formed by performing nickel electrolytic plating on a conductive base layer, and the metal body is separated at the interface with the activated surface to form a matrix, and has uneven information. A method for manufacturing a metal matrix for replicating plate-shaped objects. 2. In claim 1, the unevenness is characterized in that the conductive base layer for electrolytic plating has a thickness of between 400 Å and 2000 Å, is washed after electroless plating, and the adherend is heated and dried. A method for manufacturing a metal matrix for replicating a plate-like object having shape information.