This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2010-160902, filed on Jul. 15, 2010, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to an imprint template and a pattern forming method.
In recent years, as a fine pattern forming method an imprint method has been attracting attention. In the imprint method, a template having the same concavities and convexities as patterns to be formed on a substrate is pressed onto an imprint material having photocuring properties and coated onto the surface of a substrate subject to transfer, and is held until the imprint material extends into the concave-convex patterns. Thereafter, light illumination is performed to cure the imprint material for releasing the template from the imprint material, thereby obtaining desired patterns.
Since the imprint material is filled into the concave-convex patterns of the template due to a capillary phenomenon, the filling speed of the imprint material is different according to pattern dimension. For instance, the filling speed of the imprint material into a first small pattern is higher than that of the imprint material into a second large pattern. Therefore, when the first pattern and the second pattern are equally spaced with respect to the coating position of the imprint material, the time to fill the second pattern is longer than the time to fill the first pattern. As the pattern making time is shorter, the throughput is increased, whereby it is desired that the second pattern be filled during the same time as the time to fill the first pattern.
A release layer is provided on the surface of each of the concave-convex patterns of the template to release the template from the imprint material with ease. However, since the release layer is not provided on the end region of the template, when the imprint material is filled into the end region of the template, the imprint material remains adhesive to the end region of the released template. Therefore, the template is required to be cleaned, with the result that the throughput is lowered.
Alignment marks for alignment are provided on the end region of the template and the substrate subject to transfer. Both can be aligned by passing light from above the template to observe the alignment mark of the template and the alignment mark of the substrate subject to transfer at the same time. However, when the imprint material having substantially the same refractive index as the template is filled into the concave pattern which becomes the alignment mark of the template, it is difficult to observe the alignment mark of the template. As a result, the alignment accuracy of the template and the substrate subject to transfer is lowered.
Thus, the imprint method is required to control the filling speed of the imprint material.
Certain embodiments provide an imprint template which has a first member formed with patterns having concavities and convexities on one side thereof, and in the state in which the one side is contacted with a photocuring imprint material coated onto a substrate to be processed, cures the imprint material by light emitted from above the other side of the first member to transfer the patterns onto the imprint material. The template is provided with a second member in an end region thereof. The second member has a larger contact angle with respect to the imprint material than the first member.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Further, the surface of each of the concave-convex patterns in the center of the template 100 is provided with a release layer (not shown) to easily release the template 100 from the later-described imprint material. The release layer is not provided on the end side (outside) of the template 100 from the filling speed control film 104.
Next, a method for forming the patterns on the substrate using such template 100 will be described with reference to
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In this embodiment, the filling speed control film 104 which has a larger contact angle with respect to the imprint material 121 than the material of the template 100 is provided at the end of the template 100 to lower the filling speed of the imprint material 121 at the end of the template 100. Thereby, in the filling step of the imprint material 121 shown in
Thus, in this embodiment, the filling speed of the imprint material 121 at the end of the template 100 is lowered to prevent contamination of the template 100 and lowering of the throughput.
In addition, (at least part of) the surface of the pattern 203 is formed with a filling speed control film 204 made of a material (second member) which has a larger contact angle with respect to the later-described imprint material than the material of the template (first member; here, quartz). The filling speed control film 204 has an organic material such as organic SOG.
Next, a method for forming the patterns on the substrate using such template 200 will be described with reference to
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The liquid imprint material 221 is filled into the concave-convex pattern (pattern 202) of the template 200 due to a capillary phenomenon. Since the pattern 203 which becomes the alignment mark of the template 200 is formed with the filling speed control film 204 which has a large contact angle with respect to the imprint material 221, the pattern 203 has the filling speed of the imprint material 221 lower than that of the pattern 202.
Therefore, when the pattern 202 of the template 200 is filled with the imprint material 221, the pattern 203 is not filled with the imprint material 221 and a void 223 is formed.
When the template 200 is brought into contact with the imprint material 221, both can be aligned by passing light from the other side (the surface not formed with the concave-convex patterns) of the template 200 to observe the alignment mark of the template 200 and the alignment mark 222 of the substrate to be processed 220 at the same time. Further, here, light which does not cure the imprint material 221 is used.
When the imprint material 221 having substantially the same refractive index as the template 200 is filled into the pattern 203 which becomes the alignment mark of the template 200, it is difficult to observe the alignment mark of the template 200. As a result, the alignment accuracy of the template 200 and the substrate to be processed 220 can be lowered.
However, in this embodiment, since the surface of the pattern 203 is formed with the filling speed control film 204 which has a large contact angle with respect to the imprint material 221, the pattern 203 can be prevented from being filled with the imprint material 221 so that the void 223 can be formed in the alignment mark portion. Therefore, the alignment mark of the template 200 and the alignment mark 222 of the substrate to be processed 220 can be observed satisfactorily, so that the alignment accuracy of the template 200 and the substrate to be processed 220 can be prevented from being lowered.
The alignment of the template 200 with the substrate to be processed 220 is performed to hold the state in which the template 200 and the imprint material 221 are contacted with each other for a predetermined time.
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In this embodiment, the filling speed control film 204 which has a larger contact angle with respect to the imprint material 221 than the material of the template 200 is provided on the surface of the pattern 203 which becomes the alignment mark of the template 200 to lower the filling speed of the imprint material 221 into the pattern 203. Thereby, in the filling step of the imprint material 221 shown in
Thus, in this embodiment, the filling speed of the imprint material 221 with respect to the pattern 203 which becomes the alignment mark of the template 200 is lowered to prevent the alignment accuracy of the template 200 with the substrate to be processed 220 from being lowered.
Further, in this embodiment, an example in which the pattern 203 which becomes the alignment mark of the template 200 is provided at the end of the template 200 has been described. However, the position of the pattern 203 is not particularly limited. For instance, the pattern 203 may be located in the center of the template 200. In addition, two alignment marks (patterns 203) are not necessarily provided: one alignment mark or three alignment marks may be provided.
The concave-convex patterns 302 include a large pattern 303, and a small pattern 304. The large pattern 303 is formed with a filling speed control film 305 made of a material (second member) which has a smaller contact angle with respect to the later-described imprint material than the material of the template (first member; here, quartz). The filling speed control film 305 has a transparent metal material such as chrome nitride and zinc oxide. For instance, the filling speed control film 305 is formed on (at least part of) the bottom surface of the concave portion of the largest pattern of the concave-convex patterns 302. The film thickness of the filling speed control film 305 is about 6 nm when the depth of the concave-convex patterns 302 is 50 nm.
Which pattern of the concave-convex patterns 302 the filling speed control film 305 is formed into can be determined according to various indices. For instance, the average dimension of the concave-convex patterns 302 is calculated so that the filling speed control film 305 can be formed into the pattern having a dimension a predetermined or more times the average dimension.
Next, a method for forming the patterns on the substrate using such template 300 will be described with reference to
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Typically, the filling speed of the imprint material 321 of the large pattern is lower than that of the small pattern. However, in this embodiment, since the filling speed control film 305 which has a small contact angle with respect to the imprint material 321 is formed on the large pattern 303, the filling speed of the imprint material 321 can be higher than that when the filling speed control film 305 is not formed.
Therefore, the small pattern 304 and the large pattern 303 formed with the filling speed control film 305 can allow the filling time of the imprint material 321 to be substantially equal.
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In this embodiment, the filling speed control film 305 which has a small contact angle with respect to the imprint material 321 is provided on the large pattern 303 of the concave-convex patterns 302 of the template 300 to increase the filling speed of the imprint material 321 into the large pattern 303. Thereby, in the filling step of the imprint material 321 shown in
Therefore, in this embodiment, compared with the case in which the filling speed control film 305 is not formed, the time required for the filing step of the imprint material 321 shown in
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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2010-160902 | Jul 2010 | JP | national |