JP2010077476A

JP2010077476A - Method of manufacturing stamper

Info

Publication number: JP2010077476A
Application number: JP2008245967A
Authority: JP
Inventors: Yoshiyuki Kamata; Takuya Shimada; Shinobu Sugimura; 拓哉島田; 忍杉村; 芳幸鎌田
Original assignee: Toshiba Corp; 株式会社東芝
Priority date: 2008-09-25
Filing date: 2008-09-25
Publication date: 2010-04-08
Also published as: US20100072069A1

Abstract

A resist layer is thinned as the track pitch of a concavo-convex pattern of a mother stamper becomes narrower and the density is increased, and the difference in concavo-convex height on a master to be manufactured is reduced. As a result, a defect may occur in the uneven pattern of the resist mask on the medium due to insufficient transfer during imprinting. In order to solve this problem, a stamper manufacturing method capable of increasing the difference in height of the unevenness of the pattern is provided.
A conductive thin film is formed on a concave bottom surface of a concavo-convex pattern on a mother stamper and a top surface of a convex portion so that a film thickness of the convex top surface is larger than a film pressure of the concave bottom surface. Thereafter, a release layer 20 is formed on the surface of the conductive thin film, and subsequently immersed in a nickel sulfamate solution to form an electroformed layer 21 using an electroforming method. Thereafter, the electroformed layer is peeled off from the mother stamper, and the sun stamper 22 as the third stamper is duplicated.
[Selection] Figure 2

Description

The present invention relates to a stamper manufacturing method used as a mold used in a technique for transferring a pattern such as injection molding or imprint technique related to manufacturing of an information recording medium to a large amount of medium.

Recently, the increase in the recording capacity of information recording apparatuses has been realized by improving the recording density of magnetic recording media. As a magnetic recording medium aiming at such a high recording density, for example, concentric circles are used for recording a plurality of data. 2. Description of the Related Art Discrete magnetic recording media (Discrete Track Recording: DTR) in which a pattern including a magnetic part and a non-magnetic part is formed on a track are known.

As a method for manufacturing such a magnetic recording medium, for example, a nanoimprint method using a nickel (Ni) stamper as a mold as disclosed in Patent Document 1 is employed.
JP 2008-12705 A

By the way, a stamper used in the manufacture of a discrete type magnetic recording medium is required to have a fine processing technique for forming a concavo-convex pattern with a track pitch of 100 nm or less, for example, as the recording density of the medium increases.

However, when the track pitch of the concavo-convex pattern is narrowed and densified as described above, the drawing performance is improved when the resist layer for EB lithography is thin. As a result, the resist layer becomes thinner, and as a result, the difference in uneven height on the master disc produced may be reduced. However, a stamper with a small difference in height of the unevenness created in this way may cause defects in the uneven pattern of the resist mask on the medium due to insufficient transfer during imprinting. Further, since the difference in height of the unevenness on the medium after imprinting becomes small, there arises a problem that it is difficult to increase the recording density, for example, the signal separation performance between the adjacent tracks of the recording medium is lowered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a stamper that can increase the difference in the uneven height of the uneven pattern.

A stamper manufacturing method according to the present invention includes:
Forming an electroformed layer on the concavo-convex pattern of the master having a concavo-convex pattern on the surface, and peeling the electroformed layer to create a first stamper;
Forming an electroformed layer on the concavo-convex pattern of the first stamper, peeling off the electroformed layer and replicating the second stamper, and forming an electroformed layer on the concavo-convex pattern of the second stamper; Separating the electroformed layer and replicating the third stamper,
At least one of the first and second stampers is characterized in that a conductive thin film is formed on at least the upper surface of the concave surface of the concave / convex pattern and the upper surface of the convex portion.

The stamper manufacturing method according to the present invention includes:
A conductive film is formed on the concave / convex pattern of the master having a concave / convex pattern on the surface, an electroformed layer is formed on the conductive film, and the conductive stamp and the electroformed layer are peeled off from the master to form a father stamper. 1 process,
Forming a release layer on the uneven pattern of the father stamper, forming an electroformed layer on the release layer, and then peeling the electroformed layer to form a mother stamper;
A conductive thin film is formed on at least the top surface of the concave portion and the top surface of the concave portion of the concave / convex pattern of the mother stamper, a release layer is formed on the conductive thin film surface, and electroforming is performed on the release layer. Forming a layer, and then peeling the electroformed layer to form a sun stamper;
It is characterized by having.

ADVANTAGE OF THE INVENTION According to this invention, the stamper which can enlarge the difference of the uneven | corrugated height of an uneven | corrugated pattern can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view for explaining the stamper manufacturing method according to the first embodiment. For manufacturing the stamper, a coating apparatus, a drawing apparatus, a developing apparatus, a film forming apparatus, an electroforming apparatus, and the like are used, and the stamper is manufactured by the following process.

First, as shown in FIG. 1A, a resist layer 12 is formed by applying a resist by, for example, a spin coating method on a master substrate 11 such as glass or a Si base material using a coating apparatus.

Next, as shown in FIG. 1B, a latent image is formed by irradiating the resist layer formed by the coating apparatus with an electron beam (EB) by a drawing apparatus as shown in FIG. A concavo-convex pattern is formed by developing the resist layer 12 in which the formation of the latent image has been completed. The substrate manufactured through these series of steps is called a master 10.

Next, as shown in FIG. 1C, a conductive film 13 is formed on the concave / convex pattern of the master 10 by a film forming apparatus, and further, an electroplating process is performed by an electroforming apparatus as shown in FIG. 1D. Thus, the electroformed layer 14 is formed on the conductive film 13. And the layer which consists of the electrically conductive film 13 and the electroformed layer 14 is peeled from the original disk 10, and the father stamper 15 as a 1st stamper shown in FIG.1 (e) is created.

Next, as shown in FIG. 1F, an oxide film 16 is formed as a release layer on the uneven pattern of the father stamper 15 by an anodic oxidation method, an oxygen plasma ashing method, or the like. As shown, an electroformed layer 17 made of Ni is formed on the oxide film 16, and this is peeled off to replicate the mother stamper 18 as the second stamper shown in FIG.

The mother stamper 18 produced in this way is subjected to a process that increases the difference in the uneven height of the uneven pattern according to the present invention, that is, the difference in height between the bottom of the concave portion and the upper portion of the convex portion. In this case, as shown in FIG. 2A, the conductive thin film 19 is formed on the concave bottom surface and the convex top surface of the concave / convex pattern of the mother stamper 18. Specifically, as the mother stamper 18, a concave / convex pitch of the concave / convex pattern, that is, a track pitch Lt = 100 nm, an inclination of the concave / convex side surface, that is, a track side wall inclination Dt = 90 °, is used. A conductive thin film 19 is formed on the surface by sputtering or the like. In this case, for example, using a DC sputtering apparatus, when the film is formed at an internal pressure of 1.0 Pa, a discharge power of 100 W, and a film formation time of 225 seconds, a film of 10 nm is formed on the concave bottom surface 18a and 20 nm is formed on the convex upper surface 18b. The film thickness of the convex upper surface 18b can be made thicker than the film thickness of the concave bottom surface 18a, and the difference in the uneven height of the uneven pattern can be increased by 10 nm compared to before the treatment.

The conductive thin film 19 at this time may be formed on the side wall of the concavo-convex portion. Further, it is desirable that such a processing step be performed immediately after the mother stamper 18 is peeled from the father stamper 15. This is because when the time elapses, the surface of the mother stamper 18 is oxidized and the conductive thin film 19 may not be stably formed.

Next, as shown in FIG. 2B, a release layer 20 is formed on the surface of the conductive thin film 19 by an RIE (Reactive Ion Etching) method using oxygen or the like. Subsequently, as shown in FIG. 2C, the electroformed layer 21 is formed by dipping in a nickel sulfamate solution and using an electroforming method. Thereafter, the electroformed layer 21 is peeled from the mother stamper 18 to duplicate the sun stamper 22 as a third stamper as shown in FIG. Then, a protective film is spin-coated on the uneven pattern surface of the sun stamper 22 obtained in this way, and then dried, and if necessary, a stamper for mass transfer of the final form of the medium is performed through processes such as back surface polishing and punching. Is completed.

Here, the above-described conductive thin film 19 and release layer 20 have high physical and mechanical strength, strong against corrosion and wear, and considering the adhesion of the electroformed material with Ni, A material mainly composed of Ni is used. The electroformed layer 21 is made of Ni or a metal containing Co, S, B or P in Ni.

In the specific example shown in FIG. 2A described above, the track pitch (concave / convex pitch) Lt of the concavo-convex pattern of the mother stamper 18 is set to 100 nm, and the track side wall slope (tilt side slope) Dt is set to 90 °. Is an example, and can be applied in the range where the track pitch Lt is 10 to 100 nm and the track side wall inclination Dt is 60 to 100 °, for example. Here, the track pitch Lt is set to 10 nm because if it is 10 nm or less, it is difficult to make a difference in the uneven height even if the conductive thin film 19 is formed on the surface of the mother stamper 18. Further, the reason that the track side wall inclination Dt is set to 60 ° to 100 ° is that when the Dt is 60 ° or less, a sufficient area of the upper surface of the convex portion used as the magnetic portion of the recording medium cannot be secured. This is because, when Dt is 100 ° or more, it becomes difficult to peel the release layer 20 from the mother stamper 18. In the above description, an example in which the conductive thin film 19 on the mother stamper 18 has a thickness of 10 nm on the bottom surface of the recess and 20 nm on the top surface of the protrusion has been described as an example. Sputtering conditions such as pressure, discharge power, and film formation time may be changed to increase the film thickness on the top surface of the convex portion compared to the film thickness on the bottom surface of the concave portion, thereby increasing the height difference between the bottom portion of the concave portion and the top portion of the convex portion. .

Therefore, in this case, the conductive thin film 19 is formed on the concave bottom surface and the convex top surface of the concave / convex pattern on the mother stamper 18 to increase the difference in concave / convex height of the concave / convex pattern. Accordingly, the difference in the uneven height of the uneven pattern can be increased also for the sun stamper 22 replicated from such a mother stamper 18, so that the insufficient transfer during the subsequent imprinting can be eliminated, and the uneven pattern of the resist mask on the medium Can be reliably formed. In addition, since the difference in the uneven height of the uneven pattern on the medium after imprinting can be increased, the signal separation performance between the adjacent tracks of the recording medium can be improved, and further higher recording density can be realized. You can also. Further, since the mother stamper 18 has the concave / convex pattern surface covered with the conductive thin film 19, even if the sun stamper 22 is duplicated many times, the mother stamper 18 body is not damaged and can be used stably for a long time. .

In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary. For example, in the above-described embodiment, the case where the uneven pattern of the mother stamper 18 is processed so as to increase the difference in the uneven height has been described. However, the uneven pattern of the father stamper 15, the mother stamper 18 and the father stamper 15 are also described. Each of the concavo-convex patterns may be processed so as to increase the difference in the concavo-convex height. In this case, as described above, a conductive thin film may be formed on the concave bottom surface and the convex top surface of each concave / convex pattern so as to increase the difference in concave / convex height. In the above description, the conductive thin film is formed on the concave bottom surface and the convex top surface of the concave / convex pattern consistently. However, the conductive thin film is formed on at least the convex top surface of the concave bottom surface and convex top surface of the concave / convex pattern. May be formed. Moreover, although the shape, numerical value, etc. of embodiment mentioned above have a different location from an actual thing, these can be changed in design suitably in consideration of a well-known technique.

Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and is described in the column of the effect of the invention. If the above effect is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

The cross-sectional schematic diagram for demonstrating the manufacturing method of the stamper concerning the 1st Embodiment of this invention. The cross-sectional schematic diagram for demonstrating the manufacturing method of the stamper concerning 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Master disk, 11 ... Master disk board | substrate 12 ... Resist layer, 13 ... Conductive film 14 ... Electroformed layer, 15 ... Father stamper 16 ... Oxide film, 17 ... Electroformed layer 18 ... Mother stamper, 19 ... Conductive thin film 20 ... Peeling Layer, 21 ... Electroformed layer 22 ... Sun stamper

Claims

Forming an electroformed layer on the concavo-convex pattern of the master having a concavo-convex pattern on the surface, and peeling the electroformed layer to create a first stamper;
Forming an electroformed layer on the concavo-convex pattern of the first stamper, peeling off the electroformed layer and replicating the second stamper, and forming an electroformed layer on the concavo-convex pattern of the second stamper; Separating the electroformed layer and replicating the third stamper,
A method of manufacturing a stamper, wherein a conductive thin film is formed on at least one of the first and second stampers on at least one of the concave bottom surface and the convex top surface of the concave / convex pattern.
2. The method of manufacturing a stamper according to claim 1, wherein the conductive thin film is formed such that the thickness of the upper surface of the convex portion is larger than the thickness of the bottom surface of the concave portion.
The stamper manufacturing method according to claim 1, wherein the conductive thin film is formed on the surface of the concavo-convex pattern by a sputtering method.
The method for manufacturing a stamper according to claim 1, wherein the conductive thin film is formed with respect to a stamper having a concavo-convex pitch of the concavo-convex pattern of 10 to 100 nm and an inclination of the concavo-convex side surface of 60 to 100 °.
The method for manufacturing a stamper according to claim 1, wherein the conductive thin film is formed of a conductive thin film.
A conductive film is formed on the concave / convex pattern of the master having a concave / convex pattern on the surface, an electroformed layer is formed on the conductive film, and the conductive stamp and the electroformed layer are peeled off from the master to form a father stamper. 1 process,
Forming a release layer on the uneven pattern of the father stamper, forming an electroformed layer on the release layer, and then peeling the electroformed layer to form a mother stamper;
A conductive thin film is formed on at least the top surface of the concave portion and the top surface of the concave portion of the concave / convex pattern of the mother stamper, a release layer is formed on the conductive thin film surface, and electroforming is performed on the release layer. Forming a layer, and then peeling the electroformed layer to form a sun stamper;
A stamper manufacturing method comprising: