JPS5953690A - Production of die for precision forming - Google Patents

Abstract

PURPOSE:To obtain a die transferred faithfully with the ruggedness of a matrix by depositing a metallic material by electroforming on the matrix deposited thereon with a hard chrome plating film having a prescribed thickness, releasing the metallic material from the matrix and depositing a hard chrome plating film having the thickness equal to the thickness of the matrix. CONSTITUTION:A hard chrome plating film 2 of a thickness C is formed on the transfer surface of a nickel matrix 1 having a pit width A and an inter-pit width B in a tracking direction. A nickel stamper 3 of a required thickness is formed by electroforming on the film 2. The stamper 3 is stripped from the film 2 and a hard chrome plating film 4 of a thickness C is formed on the transfer surface side of the stamper 3. The stamper 5 transferred faithfully with the ruggedness on the surface of the matrix 1 is obtd. and the surface hardness thereof is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a mold by transferring from a master mold.

[Technical burden of the invention and its problems]

To manufacture an information recording disk such as a video disk, first, a recording signal and a tracking signal are recorded in an uneven shape on a glass master disk coated with photoresist using a laser beam to form a master disk. From this master disc, a master, mother, and stamper are sequentially produced by nickel plating or copper plating. And the stamper is gold 4. (2 as j!Z 'It
Electrostatic 8-view recording discs are manufactured by dispersing carbon particles in a molding material and compression molding the mixture.

By the way, in the molding composition in which the conductive carphone is dispersed, there are 1,! It contains abrasive particles of 6 carton particles, and when compression molding is performed using the above-mentioned stamper, scratches are created on the surface of the stamper due to the 1υf/'J slag, and these scratches are used for the next recording disc. There is a problem in that they are transferred onto the disc, resulting in unwanted electronic defects during playback of the record. To solve this problem, the surface of the stamper is usually coated with hard chrome plating of C1,] (/7111) or less to preserve the surface. Also, JP-A-5
In 6-34430, the idea of improving the scratch resistance of the stamper by applying a thin film containing adhesive to the surface of the stamper, which accurately transfers the unevenness of the surface of the mother mold, is the best. There is.

However, if a hard film is applied to the surface of the stamper, which has accurately transferred the unevenness of the mother die surface, the accurate transfer of signals will be significantly hindered, and characteristics such as duty ratio will be degraded. Furthermore, sufficient hardness cannot be obtained with a hard chromium plating thickness of 0.1 (μm) or less (G).

Therefore, in JP-A-49-103846, a hard alloy plating film was formed, and in JP-A-50-23453, a nickel shelf alloy plating film was formed on the mother mold surface, and then gold was electroformed on the alloy plating film. A method has been proposed in which a mold is manufactured by thickening the mold body and peeling between the alloy plating film and the mother mold.

However, the stamper surface, that is, the alloy film obtained by these methods, has the disadvantage that it is easily contaminated by the stabilizer contained in the molding composition.

Therefore, it is desired to realize a method of increasing the hardness of the stamper surface without impairing signal transferability. still,
Establishment of this method is strongly required not only in the field of manufacturing video disk stampers but also in other precision mold manufacturing fields that require surface hardening.

[Purpose of the invention]

The invention was made in order to solve the above defects, and the unevenness on the surface of the precision molding die faithfully transfers the unevenness on the mother mold, and the surface hardness is made to match. The purpose of the present invention is to provide a method for manufacturing a mold for use in the present invention.

[Summary of the invention]

The non-inventive method is to apply a hard chrome plating film to a thickness of C on the mother mold, where the width of the bit part formed on the mother mold is A, and the width between the bits is B, and then to coat the hard chrome plating film on the mother mold. After depositing a stamper thickly by electroforming and peeling off the stamper from the hard chrome plating pattern, a hard chrome plating film with a thickness of C is deposited on the transfer surface side of the stamper to form the bit of the master mold. It is characterized in that the width of the projection with respect to the portion is A1, and the width of the portion corresponding to between the pits of the matrix is B.

[Effect of enlightenment]

According to the present invention, it is possible to accurately transfer the widths A and B of the irregularities on the surface of the matrix l, and to increase the surface hardness compared to the case of a stamper formed by nickel plating or copper plating. Therefore, when the invention is applied to the production of stampers for video discs, it is possible to suppress the occurrence of scratches caused by the abrasive particles in the molding composition, and the transferability is not impaired. Conventionally, a hard film such as hard chrome plating is formed on the stamper, which faithfully transfers the unevenness of the surface of the mother die, so the duty ratio changes by the thickness of the hard film, which is a drawback. There was, but
According to the present invention, this problem can be solved. In addition, hard chrome plating films are less susceptible to contamination by stabilizers contained in molding compositions.

Therefore, from the above points, the life of the stamper can be significantly extended.

Furthermore, since the invention uses a technically established hard chrome plating equipment, it is easy to set the conditions. Moreover, in the normal electroforming process for the purpose of transfer, it is necessary to treat the peeling film with chromium, potassium, etc., but when nickel plating or copper plating is applied to the chromium plating, the peelability is good, so this method is suitable. The electroforming process according to the invention particularly eliminates the need for peeling R' film treatment, and is highly useful in practice. [Embodiments of the Invention] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 5 are cross-sectional views showing the steps of manufacturing a so-called molding die by transfer from a master die 7I) according to the present invention. First, as shown in Fig. 1, a plating bath of a self-composition is applied to the transfer surface of a nickel mother having a cross-sectional shape of A1 width and B bit width. As shown in FIG. 2, a chromium plating film 2 was formed to a thickness of C (0,3≠)) at a temperature of 1 fJ5 (A/dm"J) and an anode of antimony and lead.

Chromium meso+ bath composition: As shown in FIG. 3, a plating bath having the following composition was used on the chromium plating film 2 at a temperature of 50 degrees C] and a current density of 1 and 7 (A/dl++'). , sulfamic acid-sogel plating was performed under the conditions of PH4 to form a new glass cover 3 of the required thickness.

Nickel sulfamic acid plating bath: After forming the nickel stamper 3, peeling is performed between the chromium plating film 2 and the nickel stamper 3 to form the stamper 3 shown in FIG. T-fifth
As shown in the figure, to improve the transfer of the nickel stamper 3,
Using a hard chrome plating bath with the following composition, the temperature/IQ
(°C), i Torrent density addition (A/d I), anode: under the conditions of anti-silicon lead, the hard chrome plating film 4 was coated to a thickness of C.
A stamper 5 was prepared by depositing only the following materials.

Hard chrome plating bath composition 2 In this example, the radius from the center is 1 ooc + xi
), the recording was adjusted so that A = 0.6 (μ), n = Q, 5 (μ). From the stamper 5 produced as above, the vinyl chloride-vinyl acetate copolymer ioo polymer part A recording medium consisting of 4 parts by weight of dibutyltin laurate and 4 parts by weight of carbon black was compression molded to obtain a conversion type information recording disc with valley 1-j.The life and hard chromium thickness due to the occurrence of scratches at that time are shown in Table 1. In addition, as Comparative Example 1, 0.1 [J potassium chromate] was applied to the transfer surface of Mother 1.
H] After applying a peeling film treatment using a solution, Ljll was applied, and then nickel plating was performed in a nickel sulfamate bath under the same conditions as before to form a nickel 'tu, u layer, and this was then peeled off from the mother 1. and used it as a stamper.

As Comparative Example 2, the stamper obtained in Comparative 1+11 was immersed in a plating bath having the following composition.1. Black J plating was performed under the conditions of crystallinity 50 ('O) and current density 30 (A/dze).

Chrome plating bath composition: Comparative Example 11 Using the stamper obtained in Comparative Example 2, a molding composition having the same composition as in the example was compression molded to produce a valley amount conversion type information recording disc. Table 1 shows the life and chrome thickness according to scratch occurrence.

From Table 1, it can be seen that the stamper life is improved in both Examples and Comparative Example 2 compared to Comparative Example 1.

Furthermore, Examples, Comparative Example 1. Table 2 shows the measured value of the duty ratio at the 100 radius (7) position from the center of the stamper obtained in Comparative Example 2 (blank below). Furthermore, it can be seen that the value is higher in Comparative Example 2 in which a chromium plating film was applied.Example and Comparative Example 1 show a value close to 50%), and are excellent in recording transferability.

As described above, according to the method of this embodiment, it is possible to increase the surface hardness of the stamper and improve its life without deteriorating the signal reproduction characteristics resulting from the recording transferability.

Note that the present invention is not limited to the above embodiments,
It is possible to implement various modifications. For example, the thickness of the hard chrome plating film can be changed as appropriate, but the thickness should be 0.25 to 0.25 to a level that does not significantly bury the bit part with chromium.
0.35 (71) It is desirable to be able to do so. Furthermore, the method according to the present invention is applicable not only to video display.
It can be applied to the production of various precision molds that require surface hardening and transfer accuracy.

[Brief explanation of the drawing]

1 to 5 are cross-sectional views of the span bar manufacturing process according to the present invention. l...Mother, 2...Chromium plating film,
3... Nickel electroformed layer, 4... Hard chrome plating film, 5... Stamper-0 A... Bit width, B... Width between bits, C
...Chrome plating film thickness. Representative Patent Attorney Kensuke Norichika (one idiot) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] When manufacturing a mold by transfer, a hard chrome plating film is deposited on the surface of the mother mold with a predetermined thickness, and then a metal body is deposited on the hard chrome plating film by electroforming, and then the metal The special feature is that the metal body is peeled off from the hard chrome plating film, and then hard chrome plating is applied to the transfer surface Ilu of the metal body in a thickness equal to that of the hard chrome plating film deposited on the surface of the matrix. A method for manufacturing a precision molding mold having a hard film on the mold surface.