This application is based upon and claims benefit of priority from the Japanese Patent Application No. 2010-285727, filed on Dec. 22, 2010, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a method and a device for forming a pattern.
In recent years, a nanoimprint method attracts attentions as a method for forming a fine pattern. According to the nanoimprint method, an imprinting template having a concavo-convex pattern is brought into contact with a resist applied on a base substrate, the resist is cured, and the template is removed from the resist, whereby a resist pattern is formed. Then, the base substrate is processed using the resist pattern as a mask.
In addition, according to another well-known method, after the resist pattern has been formed, an inversion resin material is applied and the resist pattern is removed to form an inverted pattern corresponding to an inverted shape of the resist pattern, and the base substrate is processed using the inverted pattern as a mask.
According to the conventional method for forming the inverted pattern, the applied inversion resin material not only fills in a concave part (space part) of the resist pattern, but also exists on an upper surface of a convex part (line part). Therefore, before the resist pattern is removed, a process to expose the upper surface of the convex part is performed by removing the inversion resin material provided on the convex part.
However, a film thickness of the inversion resin material formed on the convex part in a region having a low pattern density of the resist pattern is smaller than a film thickness of the inversion resin material formed on the convex part in a region having a high pattern density of the resist pattern, so that the convex part (line part) is partially removed in the region having the low pattern density of the resist pattern at the time of the process to expose the upper surface of the convex part, which causes the pattern to be problematically thinned. In addition, the inverted pattern fluctuates in dimension, and when such inverted pattern is used as the mask, the problem is that the base substrate cannot be processed into a desired pattern.
According to a method for forming a pattern in one embodiment, a first pattern is formed on a substrate, and an upper part of the first pattern is irradiated with ultraviolet rays, to enhance a liquid-repellent property to an inversion resin material. Furthermore, according to the method for forming the pattern, the inversion resin material is applied to the substrate after the irradiation of the ultraviolet rays, the first pattern is removed after the inversion resin material has been applied to form a second pattern containing the inversion resin material, and the substrate is processed using the second pattern as a mask.
Hereafter, embodiments of the present invention will be described with reference to the drawings.
A description will be made of a method for forming a pattern according to a first embodiment of the present invention with reference to cross-sectional views of steps shown in
As shown in
After the template 103 has been brought into contact with the imprint material 102, as shown in
As shown in
As shown in
As shown in
As shown in
By the irradiation of the UV light, a liquid-repellent property of the surface of the mold pattern 104 to an after-mentioned inversion resin material 110 is changed. Specifically, a contact angle of the side surface of the convex part 105 of the mold pattern 104 which has been hardly irradiated with the UV light, with respect to the inversion resin material 110 is about 30°. Meanwhile, a contact angle of the upper surface of the convex part 105 of the mold pattern 104 which has been irradiated with the UV light, with respect to the inversion resin material 110 is about 80°.
After the irradiation of the UV light, as shown in
Due to the irradiation of the UV light in the step shown in
As shown in
RIE using oxygen plasma. Thus, an inverted pattern 120 is formed such that it is composed of the inversion resin material 110 and has a pattern shape corresponding to an inverted shape of the mold pattern 104.
As shown in
Thus, after the base substrate 101 has been processed, as shown in
Thus, according to this embodiment, since the mold pattern 104 is irradiated with the UV light to enhance the liquid-repellent property of the upper surface of the convex part 105, a film of the inversion resin material 110 is not formed on the upper surface of the convex part 105, and only the space part 106 is filled with the inversion resin material 110. Therefore, it is not necessary to perform a process to expose the upper surface of the convex part 105 of the mold pattern 104, so that the convex part 105 is not thinned. In addition, the inverted pattern 120 is prevented from fluctuating in dimension, and dimensional precision can be improved. In addition, the base substrate 101 can be processed into a desired pattern.
A method for forming a pattern in a comparison example will be described with reference to
As shown in
As shown in
As shown in
Then, as shown in
As shown in
According to the method for forming the pattern in the comparative example, since a dimension fluctuates in the inverted pattern 220, the base substrate 201 cannot be processed into a desired pattern.
Meanwhile, according to the first embodiment, since the liquid-repellent property is enhanced on the upper surface of the convex part 105 because the mold pattern 104 is irradiated with the UV light, the film of the inversion resin material 110 is not formed on the upper surface of the convex part 105, and the film of the inversion resin material 110 is only formed in the space part 106. Therefore, it is not necessary to perform a process to expose the upper surface of the convex part 105 of the mold pattern 104, so that the convex part 105 is not thinned (in the region 104b having the low pattern density). In addition, the inverted pattern 120 is prevented from fluctuating in dimension, and the dimensional precision can be improved. In addition, the base substrate 101 can be processed into the desired pattern.
A method for forming a pattern according to a second embodiment of the present invention will be described with reference to cross-sectional views of steps shown in
As shown in
As shown in
Due to the irradiation of the UV light, a liquid-repellent property on the surface of the mold pattern 304 to an after-mentioned self-assembled material 310 is changed. Specifically, a contact angle of the side surface of the convex part 305 of the mold pattern 304 which has been hardly irradiated with the UV light, with respect to the self-assembled material 310 is about 10°. Meanwhile, a contact angle of the upper surface of the convex part 305 of the mold pattern 304 which has been irradiated with the UV light, with respect to the self-assembled material 310 is about 30°.
After the irradiation of the UV light, as shown in
For example, the self-assembled material 310 is dropped and subjected to spin-coating. As the self-assembled material 310, for example, a mixture solution of polystyrene-polyethylene oxide (PS-PEO) and spin-on glass (SOG) is used.
Due to the irradiation of the UV light in the step shown in
As shown in
As shown in
In a case where a film of the self-assembled material 310 is formed on the upper surface of the convex part 305 in the step shown in
As shown in
Then, after the process of the base substrate 301, as shown in
Thus, according to this embodiment, the mold pattern 304 is irradiated with the UV light to enhance the liquid-repellent property on the upper surface of the concave part 305, so that a film of the self-assembled material 310 is not formed on the upper surface of the concave part 305, and the film of the self-assembled material 310 is only formed in the space part 306. Therefore, the self-assembled pattern 330 can be formed with high precision. In addition, the base substrate 301 can be processed into a desired pattern.
The method for forming the pattern according to the first embodiment can be executed by a pattern forming device 400 shown in
Specifically, the steps shown in
While the three imprint parts 411 to 413 are provided in
In addition, when an ashing part to remove the resist is further provided in the pattern forming device 400, and the self-assembled material 310 is applied by the applying part 420, the method for forming the pattern according to the second embodiment can be executed.
Specifically, the steps shown in
In addition, a contact angle indicator to automatically measure the contact angle between the surface of the mold pattern 104 (304) and the inversion resin material 110 (self-assembled material 310) may be provided in the pattern forming device 400.
In addition, while the mold pattern 104 (304) is formed by the imprint method using the template 103 in the first (second) embodiment, the mold pattern 104 (304) may be formed by the well-known photolithography.
In addition, the inversion resin material 110 (self-assembled material 310) is applied by the spin-coating in the first (second) embodiment, it may be applied by an ink-jet method. For example, when a density difference in the mold pattern 104 (304) is large because there is a large space part, the inversion resin material 110 (self-assembled material 310) is preferably applied with a discharge distribution adjusted by the ink-jet method based on a density distribution of the mold pattern 104 (304).
While the silicon-containing resist is used as the inversion resin material 110 in the first embodiment, SOG may be used. In addition, while the mixture solution of PS-PEO and SOG is used as the self-assembled material 310 in the second embodiment, another material may be used.
In addition, while UV-curing type SiO2 material is used for the mold pattern 104 (304), and the liquid-repellent property on the surface is changed by the irradiation of the UV light in the above embodiments, a photosensitive resin may be used for the mold pattern 104 (304), and the liquid-repellent property may be changed by a plasma treatment.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2010-285727 | Dec 2010 | JP | national |