JP2901989B2 - Manufacturing method of duplication stamper - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a stamper for duplication in which a glass substrate provided with a conductive film is immersed in a nickel electroforming bath to obtain a stamper.

[Prior Art] Conventionally, a thin disk-shaped metal plate called a stamper has been used in optical disk, video disk, compact disk, audio disk, holography, metal mesh, and the manufacturing process of an ink jet nozzle. It is well known that

When manufacturing this stamper, for example, after applying a photoresist layer to a glass substrate, each step of exposure and development by photolithography is performed on the photoresist layer to write a signal, As a result, a glass master on which a fine pattern having irregularities is formed is obtained. Next, a conductive nickel film for electroforming is formed by vacuum deposition, sputtering, CVD, or the like, and a metal film layer is formed by nickel electroforming. After such nickel electroforming, the conductive nickel film and the metal film layer integrated therewith are peeled off from the glass master to wash and remove the photoresist layer to obtain a stamper.

In general, the stamper formed in this manner is used as a mold, and the concave and convex fine pattern on the stamper is transferred to a plastic substrate, which is used as, for example, an optical disk substrate. When the consumption of the stamper becomes a problem from the standpoint of mass production, the above process is repeated to manufacture the stamper, or the following process is employed to simplify the process and improve the yield. That is, the stamper is used as a master mold, and after a release coating treatment is performed on the surface of the master, a metal layer is formed by nickel electroforming, and the metal layer is separated to obtain a single mother. In this case, the uneven fine pattern on the mother is opposite to that of the master. Further, a stamper is obtained by repeating release film treatment, nickel electroforming and peeling on the mother. This stamper has the same concavo-convex shape as the master. In such a method, for example, when five mothers are duplicated from one master and five stampers are duplicated from each mother, 25 stampers are obtained from one master in the end,
It allows mass production.

In the step of forming the master, mother, and stamper in such a stamper manufacturing process, the so-called nickel electroforming method is applied as described above, and any material to be plated in an electrolytic cell having a predetermined plating bath is used. Is used as a cathode, and a film is formed by applying a voltage between the cathode and the anode.

[Problems to be Solved by the Invention] However, in each of the master, mother, and stamper duplication steps as described above, for example, when the mother is duplicated from the master, the mother is duplicated even if the release coating is performed under the same conditions. Due to the electroforming conditions at the time of the formation, the peelability of the mother from the master varies, and as a result, the fine irregularities are damaged, and a problem that satisfactory signal characteristics cannot be obtained often occurs.

Accordingly, an object of the present invention is to provide a method of manufacturing a stamper for duplication, which can obtain a high-quality stamper having a good groove shape after peeling.

[Means to Solve the Problems] In order to achieve the above object, the present invention provides a method for forming a concave and convex fine shape on a glass substrate by photolithography, applying a conductive film, and immersing the stamper in a nickel electroforming bath to form a stamper. In the method for producing a duplicating stamper thus obtained, the electroforming duplication is started when the natural electrode potential generated by immersion in the nickel electroforming bath is -130 mv or more with respect to the reference electrode.

[Operation] In the apparatus having such a configuration, nickel electroforming is performed while the electroforming conditions are constantly monitored, and variations in the electroforming conditions are prevented.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

First, the manufacturing process of the stamper will be described with reference to FIG. With respect to the glass substrate 1 shown in FIG.
After the photoresist layer 2 is applied in the form of a film as shown in FIG. 2 (b), each step of exposure and development by photolithography is performed on the photoresist film layer 2 to write a signal. As a result, a fine pattern having irregularities as shown in FIG. 2 (c) is formed, and a glass master is obtained. Next, as shown in FIG. 2 (d), a conductive coating layer 3 for electroforming is formed by vapor deposition, sputtering, CVD or the like. Further, after the metal film layer is formed by the nickel electroforming method, the conductive thin film 3 is formed.
And the metal film layer integrated therewith is peeled from the glass master and the photoresist is washed and removed.
A stamper, that is, a master 4 as shown in FIG.

In general, the master 4 formed as described above is used as a mold, and the fine irregular pattern on the master 4 is transferred to a plastic substrate and used as, for example, a substrate for an optical disk. If the consumption of the master 4 becomes a problem from the standpoint of mass production, the above steps are repeated to manufacture the master 4, or the following steps are taken to simplify the steps and improve the yield. That is, after the master 4 is used as a matrix, as shown in FIG. 2 (f), after the release coating layer 5 is formed on the surface of the master 4,
A metal layer is formed by nickel electroforming, and a single mother is obtained by removing the metal layer. In this case, the uneven fine pattern on the mother is opposite to that of the master 4.

An apparatus used in the nickel electroforming method in this case will be described with reference to FIG. As shown in FIG. 1, in an electrolytic cell 11 for storing an electrolytic solution, a cathode 12 formed by processing and forming a release film layer 5 on the master 4 and an anode 13 made of a nickel material in a hollow container shape are provided. Is soaked. The above cathode
12 and the nickel anode 13 are arranged so as to be completely immersed in the electrolytic solution. The electrolytic plating solution for nickel electrolysis used in this example contains nickel sulfamate at 450 g / l, and the electrolytic solution temperature is 50
° C and PH values are set to 4.0.

Further, the electrolytic plating solution in the electrolytic cell 11 is connected to the saturated potassium chloride solution in the reference tank 15 via the salt bridge 14, thereby constructing an electrochemical measuring system.
In the above-mentioned reference tank 15, a saturated ginger electrode (SCE) 16 as a reference electrode is immersed. Further, a cathode 12, a nickel anode 13 in the electrolytic cell 11 and a saturated galvanic electrode (SCE) 16 in the reference cell 15 are connected to an electrometer 17, respectively. Is monitored and nickel electroforming is performed.

Hereinafter, results of three examples in which nickel electroforming was actually performed will be described.

First, in the first embodiment, when the natural electrode potential measured by the electrometer 17 became -80 mV, nickel electroforming was started to duplicate the mother. FIG. 3 shows the results of measuring the depths of the ID pits of the master and the mother after the separation. As described above, according to the first embodiment, good transferability of the groove shape is maintained. FIG. 4 shows the result of measuring the amount of warpage of the mother after peeling. As described above, according to the first embodiment, a high-quality stamper without warpage can be obtained. Furthermore, when obtaining a duplicate of Sun from the mother, the electrode potential is also -80 mV.
Then, nickel electroforming was started to obtain sun. The same result as that of the mother was obtained for this sun. That is, according to the first embodiment, it is possible to obtain a high-quality stamper having good groove shape transferability and no warpage.

In the second embodiment, when the natural electrode potential measured by the electrometer 17 became -130 mV, nickel electroforming was started to duplicate the mother. FIG. 3 shows the results of measuring the depths of the ID pits of the master and the mother after the separation. As described above, also according to the second embodiment, the transferability of the groove shape is well maintained. FIG. 4 shows the result of measuring the amount of warpage of the mother after peeling. As described above, according to the second embodiment, a high-quality stamper without warpage can be obtained. Further, when a copy of Sun is obtained from the mother, the electrode potential is similarly-
When the voltage reached 130 mV, nickel electroforming was started to obtain a sun. This sun also obtained the same results as the mother. That is, according to the second embodiment, a high-quality stamper having good groove shape transferability and no warpage can be obtained.

Further, as a comparative example, a method of starting nickel electroforming and duplicating the mother when the electrode potential became -280 mV was implemented. FIG. 3 shows the results of measuring the depths of the ID pits of the master and the mother after the separation. In this comparative example, the mother ID pit was shallower by 60 mm than the master ID pit. FIG. 4 shows the result of measuring the amount of warpage of the mother after peeling. In this comparative example, the amount of warpage of the mother was 90 μm. Similarly, when a duplicate of the sun was obtained from the mother, nickel electroforming was started when the electrode potential became -280 mV to obtain a sun. The Sun ID pit is 100 mm shallower than the master ID pit, and the warpage is 150μ.
m had been reached. That is, according to this comparative example, not only the transferability of the groove shape becomes poor, but also the warpage becomes large, so that a considerable difference is observed in the groove shape on the inner and outer circumferences of the disk, and the pit depth is reduced. Deterioration of the signal characteristics became so great that quality could not be maintained.

[Effects of the Invention] As described above, the present invention can provide a high-quality stamper having good groove shape transferability.

[Brief description of the drawings]

1 is an explanatory side view showing an electroforming apparatus according to an embodiment of the present invention, FIGS. 2 (a) to 2 (f) are explanatory views showing an electroforming process, and FIG. 3 is a reproduction of a groove of a duplicate stamper. FIG. 4 is a diagram showing the amount of warpage of the duplication stamper. 11 ... electrolyzer, 12 ... cathode, 13 ... anode, 17 ... electrometer.

Claims (1)

(57) [Claims] A method for producing a stamper for duplication, wherein a stamper is obtained by forming a concave / convex fine shape on a glass substrate by photolithography, applying a conductive film, and then immersing the stamper in a nickel electroforming bath. A method for producing a duplicating stamper, characterized in that electroforming duplication is started when a natural electrode potential generated by immersion in a nickel electroforming bath is -130 mv or more with respect to a reference electrode.