JPS62239446A - Production of master stamper for optical memory - Google Patents

Abstract

PURPOSE:To deliver an inexpensive good-quality stamper in a short time by producing many duplicated stampers with one Ni electrocasting from a glass master disk. CONSTITUTION:A Cr thin film 2 is formed on the specularly polished glass master disk 1, an Ni thin film 3 is formed thereon in the thickness identical to the desired depth of a groove, and a photoresist 4 is coated, exposed, and developed. The exposed Ni thin layer 3 is etched by a dry etching method using reverse sputtering, a photoresist in which a groove and a bit shape are formed is removed, then mold releasing treatment is carried out by dichromic acid, and an Ni electrocast layer 5 having desired thickness is released number of times of electrocastings is thus reduced from three to one, hence the device cost is reduced, an inexpensive stamper can be supplied, and the time of production and delivery can be reduced.

Description

[Detailed description of the invention] [Fields of use on Motogaawa] do.

[Conventional technology]

The conventional method for using a mother stamper for optical memory is to coat a glass master with positive type photoresist '2, expose and develop it to form all the groups and bits, and then completely form a conductive film on top of it, and then apply it to the thickness of the process. Ni electroforming not fully formed %Ni
[Remove the rust layer from the glass master to form a mother stamper.

Next, the mother stamper was subjected to a mold release treatment using a 5% aqueous solution of dichromic acid, and the mother stamper was coated with Ni to the thickness of the treatment.
Form an electroformed layer.

When the Ni electroformed layer is peeled off from the mother stamper, a sub-mother is formed.

Next, the female mold treatment with dichromic acid on the above sub-mother? Then, the Ni electroforming tank is completely formed to the thickness of the treatment.

As mentioned above, when the Ni layer is peeled off from the sub-mother, a stamper is formed.

C! [Problems to be solved by Irumei] However, in the above-mentioned conventional technology, the stamper is made /7) 177″N4′:
)! 'i14 Sue Xl '1.1n, aL4LL+4'y
r! Since electroforming is performed to a thickness of 1.4+, -+Knnμ or more, it takes at least 2 to 5 hours to perform electroforming once.

The fact that three long processes are required is a serious problem in manufacturing. In other words, since it is not suitable for mass production, a large number of devices are required, which increases the cost of the device, and the process is long, resulting in a low yield and an increase in manufacturing costs.

Also, in terms of delivery time, electroforming is required three times, so it takes two days to Md.

Therefore, the present invention is intended to solve all of these problems, and its purpose is to produce products using a stamper, which in the conventional method required electroforming three times. By completing the process only once, it is possible to supply a low-cost stamper with less mounting + It'N use, and to shorten the manufacturing delivery time.

[The tth method to solve all problems]

The original memory stamper of the present invention is a Cr4 layer of 500A or more on a glass master disk troweled to a mirror surface. On top of that, a NIP layer is formed to the same thickness as the desired depth, and then photoresist is applied. ! -Coat and expose, now 1! Is the photoresist etched by a dry etching method using exposed Ni4 high-if reverse spatter to form all the group and bit shapes?
After removal, a mold release treatment was performed using dichromic acid, and a Ni layer of the desired thickness was peeled off from the mold release treatment surface. Features.

[Effect]

According to the above configuration of the present invention, metal iU is formed on the glass master disk.
Groups and bits are formed in -, and the entire surface is covered with a metal # layer, so the surface is subjected to III type treatment with dichromic acid, a Ni electroformed layer is formed to the thickness of the treatment, and Ni electroformed rust is formed. When peeled off from the layered glass master, it peels off from the release-treated surface, making it possible to make multiple copies from one glass master. In other words, a stamper can be manufactured from a glass master in one KM.

[Real example]

First, φ200 with at least one side mirrored.
Glass master disk 1 with a thickness of 6 m% is coated with CrO thin Pa2' to a thickness of 5008 or more, and then Ni thin II@5 on top of it.
k Formed to have the same thickness as the desired group and bit depth. As the method for forming the metal # film, vapor deposition and sputtering are preferred from the viewpoint of osteoporosis and external factors. Next, the surface of the Ni Hironokan 6 is coated with a photoresist 4 to a thickness of λ000 to 400 OA. The preferred method for applying the resist is a spin code method. In this case, the thickness of the photoresist 4 may vary somewhat. As the photoresist 4 used, Az-1350 positive resist manufactured by Hoechst is suitable.

Next, the film was exposed to light using a special laser cutter M/C' without being subjected to a brebake at 90° C. for 50 minutes.

The wavelength is 4500 in the part where bits and groups are formed.
Nearly 11 tons of laser light will be irradiated.

Next, a special developer? Use it to develop. The preferred developing method is a spray method. After development, post-baking is performed at 120° C. for 30 minutes to increase the layer density of the resist.

Next, the photoresist 4 is partially uncovered using a dry etching device mk using reverse sputtering.
J m 5 (Bit group is formed by daytime etching.Ion beam etching in an inert environment is superior in terms of very little side etching and fine graining. .

The etching conditions that have remained the same for generations are Ar inert gas, ion energy 500 eV, normal incidence angle, and ion
The current density is 10A/. It is l.

There are two reasons why a Cr thin film was formed under the Ni thin 11 bullet 6.
There is one. One is that the etching speed of Cr is slower than that of Ni. N
i's etching time? Once determined, only Ni is etched and Cjr is hardly etched, so the depths of bits and groups become uniform. 2 are Ni thin 1
i! If the glass surface is exposed during 65k etching, it will not stick to that part and will not be removed, so it serves as a solidification treatment film to make the Ni' cast in the next step more effective.

Next, the photoresist 4 is chemically removed. Dredging solvents such as acetone and pyrrolidone are suitable for removing the photoresist.

Next, the entire surface of the metal thin film is subjected to mold release treatment. As the mold release treatment method, treatment with tunic chromic acid is suitable. By immersing the surface in the 5X point ammonium chromate aqueous solution for 1 minute, a sufficient mold release treatment film is formed.

Next, after a mold release treatment, a Nig cast layer rust layer is formed to the thickness of the pile.

Next, the first stamper is created by peeling off the Ni from the mold.

By forming the Ni electroforming layer 5 again on the remaining glass master, a second stamper is completed.

As described above, a large number of duplicate stampers can be made from a glass master by one electroforming process.

[Invention effect]

As described above, according to the present invention, the glass master disc has a
Form a Cr thin layer of A or more, and then apply a Ni thin film on top of it to the same thickness as the desired groove depth. A photoresist is applied, exposed and developed, and the exposed Ni thin film is etched by a dry etching method using gold reverse sputtering to form all groups and pits. After the photoresist is removed, a mold release treatment with chromic acid is performed, and then A large number of packaged stampers are manufactured using a method for manufacturing a mother stamper for memory, which is characterized by forming Ni (Ni) and JJ on the surface and removing the Ni 1IVAi layer from the treatment that makes it difficult to form. Kotot Town 11
It is something that I have seen, and can be supplied in a short period of time with good quality at the primary cost.

[Brief explanation of drawings]

1 to 6 are process cross-sectional views showing the method for manufacturing a mother stamper for optical memory according to the present invention. that's all

Claims (1)

[Claims] 1) Cr of 500 Å or more on a mirror-polished glass substrate
Form a thin layer and add N to the same thickness as the desired groove depth.
A thin Ni layer is formed, a photoresist is applied, exposed and developed, the exposed Ni thin layer is etched using a dry etching method using reverse sputtering to form groups and pit shapes, and after the photoresist is removed, it is etched using dichromic acid. After performing mold release treatment, a Ni electroformed layer is formed to a desired thickness on top of the mold release treatment, and the N
i. A method for producing a mother stamper for optical memory, characterized in that the electroformed layer is peeled off from the mold release treated surface.