JP2008074049A - Mold for heat imprint and manufacturing method of mold for heat imprint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent mold made from nickel for heat imprints which has a stable mold release layer. <P>SOLUTION: In a mold for imprints which transfers concavo-convex patterns formed on a mold, the mold material of a mold 100 for heat imprints comprises nickel prepared by electroforming or the like, further the mold surface comprises a nickel oxide such as Ni<SB>2</SB>O<SB>3</SB>or the like which is formed by an oxidization process or the like by an NMP (N-methyl-2-pyrrolidinone) or the like, and preferably an organic fluorine compound adheres to the surface further. And the manufacturing method is obtained. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  In the manufacturing process of various products such as semiconductor devices, optical components such as optical waveguides and diffraction gratings, recording devices such as hard disks and DVDs, biochips for DNA analysis, displays such as diffusion plates and light guide plates, etc. The present invention relates to a thermal imprint mold that can be used for pattern formation using a method and a method for manufacturing the same.

  Until now, a method of optically transferring a pattern has been used to form a pattern that requires fine processing, such as a manufacturing process of a semiconductor device. As an example, a photomask in which a pattern made of an opaque material such as chromium is formed on a part of a transparent substrate such as glass is formed, and this is formed on a semiconductor substrate (hereinafter referred to as a sensitive substrate) coated with a resist. The pattern of the photomask is transferred to the sensitive substrate by placing it directly or indirectly and irradiating light from the backside of the photomask to selectively expose the resist in the light transmitting portion. It was. This technique is generally called a photolithography method. Further, in the current semiconductor device manufacturing process, a method of optically reducing a mask pattern and transferring the pattern onto a semiconductor substrate has become mainstream.

  However, in these pattern forming methods, the size and shape of the pattern to be formed greatly depend on the wavelength of light to be exposed. For example, in the manufacture of advanced semiconductor devices in recent years, the exposure wavelength used for photolithography is 150 nm or more, while the minimum line width is 65 nm or less, reaching the resolution limit due to the light diffraction phenomenon.

  In order to increase the resolution of the resist, super-resolution techniques such as proximity correction (OPC), phase shift mask, and modified illumination are used, but the mask pattern is faithfully transferred onto the semiconductor substrate. It has become difficult to do.

  Further, in the case of reduced projection exposure, since alignment accuracy is required not only in the horizontal direction of the substrate but also in the vertical direction, precise stage control (X, Y, Z, θ) of a photomask and a semiconductor substrate is required. Therefore, there has been a drawback that the cost of the apparatus becomes high.

  In addition to the manufacture of semiconductor devices, as long as photolithography is used in various pattern formations such as displays, recording media, biochips, optical devices, etc. The problem of the required apparatus cost similarly exists, and the mask pattern cannot be faithfully transferred.

  From such a background, S.I. Y. Chou et al. Have proposed a technique called imprint method (or nanoimprint method) that is very simple but suitable for mass production and can transfer a much finer pattern faithfully than conventional methods (for example, non-imprint method). (See Patent Documents 1 and 2).

  Although there is no strict distinction between the imprint method and the nanoimprint method, the nanometer order method used for manufacturing semiconductor devices and diffraction gratings is called the nanoimprint method, and other micrometer order methods are imprinted. Often called the law. Hereinafter, all are referred to as an imprint method.

  A method for imprinting using a thermal cycle is called a thermal imprint method, and a method for imprinting using UV light is called a photoimprint method.

  In the imprint method, the releasability between the mold and a resin pattern such as a resist generated on the substrate is extremely important. In imprinting, when the mold and the resin are separated after pressing, a phenomenon in which the resin is partially deformed or peeled off with the mold due to adhesion and friction between the mold and the resin is observed. That is, all or part of the resin resist remains on the mold side, and an appropriate pattern is not formed on the silicon substrate. This is because the surface energy of the mold or resin is large.

  Therefore, in order to avoid such separation of the substrate and the resin, there is a method of improving the releasability between the mold and the resin on the substrate by forming a fluoropolymer having a small surface energy as a release agent on the mold surface. In general, a silane coupling agent solution is allowed to act on the OH groups of the silicon oxide film on the mold surface as a release agent to form a film having a low surface energy (called a release layer) on the mold surface. ing. This release layer can reduce the adhesive force between the mold and the resin.

  However, it is generally known that a mold release agent is difficult to adhere to a metal mold for thermal imprinting, particularly nickel, and a stable release layer cannot be formed.

Thus, a method has been proposed in which the mold surface to which the release agent is attached is replaced with another element such as chromium, and the release agent is attached by oxidizing the surface (Patent Document 1).
JP 10-308040 A Appl.Phys.Lett., Vol.67, p.3314 (1995) A thorough explanation of nanoimprint technology Electric Journal Published November 22, 2004 P20-38

  However, the method disclosed in Patent Document 1 has a problem that the manufacturing process of the mold becomes complicated. In addition, because the sputtering method is used, the chrome film tends to be thin on the side walls of the surface uneven pattern, or mold release is likely to occur due to pinholes during sputtering. But there is a problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a nickel mold for thermal imprinting with good releasability.

  As a result of intensive studies, the present inventor has found that a release agent mainly composed of a fluorine compound can be easily adhered by using nickel oxide on the surface.

  The invention according to claim 1 of the present invention is an imprint mold for transferring a concavo-convex pattern formed on a mold, wherein the mold material is made of nickel, and the mold surface is made of nickel oxide. It is a mold.

The invention according to claim 2 of the present invention is the mold for thermal imprinting according to claim 1, wherein nickel oxide (III) (Ni ₂ O ₃ ) is contained in the nickel oxide.

The invention according to claim 3 of the present invention is the mold for thermal imprinting according to any one of claims 1 and 2, wherein an organic fluorine compound is adhered to the nickel oxide surface.

  The invention according to claim 4 of the present invention is the mold for thermal imprinting according to any one of claims 1 to 3, wherein the nickel is electroformed nickel.

  The invention according to claim 5 of the present invention is the mold for thermal imprinting according to any one of claims 1 to 4, wherein the nickel oxide is obtained by oxidizing the surface of electroformed nickel. .

  The invention according to claim 6 of the present invention is characterized in that the nickel oxide is oxidized with NMP (N-methyl-2-pyrrolidinone), and the heat-in according to any one of claims 1 to 5 It is a mold for printing.

  The invention according to claim 7 of the present invention is a method for manufacturing a mold for thermal imprinting, characterized in that after the mold is formed by electroforming nickel, the surface is oxidized.

  The invention according to claim 8 of the present invention is the method for producing a mold for thermal imprinting according to claim 7, wherein the oxidation treatment is performed using a solution containing NMP (N-methyl-2-pyrrolidinone). .

  The invention according to claim 9 of the present invention is the method for manufacturing a mold for thermal imprinting according to any one of claims 7 and 8, wherein an organic fluorine compound is adhered to the surface of nickel oxide.

  The mold for thermal imprinting of the present invention is characterized in that the mold surface is made of nickel oxide. Thereby, a mold release agent becomes easy to adhere and a stable mold release layer can be formed. Moreover, the nickel mold surface can be made into nickel oxide only by performing oxidation treatment. For this reason, the manufacturing process can be simplified.

  As described above, the mold for thermal imprinting and the manufacturing method thereof according to the present invention can be released from the pure nickel mold, can omit the conventional complicated mold manufacturing process, and can reduce the mold manufacturing cost.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic cross-sectional view showing an embodiment of the thermal imprint mold of the present invention.

  The thermal imprint mold 100 of the present invention includes a mold 10 made of nickel, 11 made of nickel (III) oxide, and a release layer 12 made of an organic fluorine compound. With this configuration, the release layer can be stabilized.

  The manufacturing method of the mold for thermal imprinting of the present invention will be described.

  In the mold for thermal imprinting of the present invention, the mold 10 is first produced by a known method such as electroforming.

  Next, the mold 10 is oxidized to form a nickel (III) oxide layer 11 on the surface. The oxidation treatment can be performed by a method such as thermal oxidation. However, as shown in the pH potential diagram of Ni, the solution can also be treated by solution treatment by setting the ORP (Oxidation-Reduction Potential) and pH of the solution to appropriate values. Is possible. Preferably, a solution containing NMP is used. The NMP content is preferably 50% or more, the treatment temperature is preferably 40 ° C. or more, and the treatment time is preferably 3 minutes or more.

  Next, the organic fluorine compound 12 is coated on the surface of 11. Various methods such as a method of immersing or spin-coating in an organic fluorine compound and a method of depositing an organic fluorine compound can be used for coating.

  A mold made of pure nickel not containing impurities such as phosphorus was prepared. The mold was immersed in an NMP (N-methyl-2-pyrrolidinone) solution and surface-treated. The immersion temperature was 70 ° C. and the immersion time was 30 minutes. After being immersed for 30 minutes, it was lifted from the NMP solution, rinsed with pure water for 20 minutes, and then naturally dried. The sample surface was measured by XPS (X-ray photoelectron spectroscopy), and the state of nickel was analyzed. Further, an organic fluorine compound was deposited and coated.

  A mold made of pure nickel not containing impurities such as phosphorus was prepared. This mold was immersed in a solution containing 60% of NMP (N-methyl-2-pyrrolidinone) and surface-treated. The immersion temperature was 70 ° C. and the immersion time was 30 minutes. After being immersed for 30 minutes, it was lifted from this solution, rinsed with pure water for 20 minutes, and then naturally dried. The sample surface was measured by XPS (X-ray photoelectron spectroscopy), and the state of nickel was analyzed. Further, an organic fluorine compound was deposited and coated.

  A mold made of pure nickel not containing impurities such as phosphorus was prepared. The mold was rinsed with pure water for 20 minutes without being immersed in the chemical solution, and then naturally dried. The sample surface was measured by XPS (X-ray photoelectron spectroscopy), and the state of nickel was analyzed. Further, an organic fluorine compound was deposited and coated.

<Comparison evaluation>
The samples prepared in Examples 1 to 3 were heated at 270 ° C. in an oven assuming thermal nanoimprint. Thereafter, the surface was measured by XPS to investigate the presence of fluorine. The results are shown in Table 1. As is clear from Table 1, in Examples 1 and 2 where the state of Ni ₂ O ₃ exists, fluorine was detected even after heating, but in Example 3 where Ni ₂ O ₃ does not exist, heating occurred. It can be seen that fluorine was not detected later and the organic fluorine compound had disappeared.

  As is apparent from the above comparative evaluation, it can be seen that the organic fluorine compound is firmly attached to the nickel surface by the nickel surface treatment of the present invention.

It is a conceptual sectional view of the mold for thermal imprinting of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mold 11 ... Nickel (III) oxide layer 12 ... Release layer 100 which consists of organic fluorine compounds ... The block diagram of the mold for thermal imprinting of this invention

Claims (9)

  An imprint mold for transferring a concavo-convex pattern formed on a mold, wherein the mold material is made of nickel, and the mold surface is made of nickel oxide. The mold for thermal imprinting according to claim 1, wherein nickel oxide (III) (Ni ₂ O ₃ ) is contained in the nickel oxide.   The mold for thermal imprinting according to claim 1, wherein an organic fluorine compound is adhered to the nickel oxide surface.   The thermal imprint mold according to any one of claims 1 to 3, wherein the nickel is electroformed nickel.   The mold for thermal imprinting according to any one of claims 1 to 4, wherein the surface of electroformed nickel is oxidized by nickel oxide.   The mold for thermal imprinting according to any one of claims 1 to 5, wherein nickel oxide is oxidized by NMP (N-methyl-2-pyrrolidinone).   A method for producing a mold for thermal imprinting, characterized in that after the mold is formed by electroforming nickel, the surface is oxidized.   The method for producing a mold for thermal imprinting according to claim 7, wherein oxidation treatment is performed using a solution containing NMP (N-methyl-2-pyrrolidinone).   The method for producing a mold for thermal imprinting according to claim 7, wherein an organic fluorine compound is adhered to the surface of nickel oxide.

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