This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2010-66517, filed on Mar. 23, 2010, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a template and a method of manufacturing the same, and a semiconductor device manufacturing method using the template.
As a conventional technique, there is known a stamper formed in such a manner that the thickness between a pattern formation surface, where a concave/convex pattern is formed, and a back surface gradually decreases toward the outer edge side (e.g., see Japanese Patent Application Laid-Open No. 2007-190735).
With this stamper, a uniform pressure can be applied over a resin layer to which the concave/convex pattern is to be transferred, so that the concave/convex pattern can be transferred to the resin layer with high precision.
In the conventional stamper, however, the thickness gradually decreases toward the outer edge side regardless of the density of the concave/convex pattern. Therefore, regarding a reaction force arising from the flexure of the stamper at the time of separation of the resin layer and the stamper, the reaction force exerted on the stamper increases as the thickness of the stamper decreases. This can cause a defect in the shape of a resist pattern.
a) is a plan view of a template according to an embodiment, and
a) through 2(f) are process drawings of a template manufacturing method according to the embodiment;
a) through 3(d) are process drawings of a semiconductor device manufacturing method using the template according to the embodiment; and
a) through 4(h) are cross-sectional views of main portions of templates according to modifications.
According to one embodiment, there is provided a template which includes a first region and a second region. The first region is provided with a first pattern of a plurality of recessed portions formed on a main surface of the template, and has a first thickness. The second region is provided with a second pattern of a plurality of recessed portions formed on the main surface of the template, and has a second thickness different from the first thickness. The second pattern is different from the first pattern in at least one of interval and dimension of the recessed portions.
a) is a plan view of a template according to an embodiment, and
The template 1 includes a first region 14 in which a pattern 142 as a first pattern made up of a plurality of recessed portions 22 is formed on the main surface 10 and which has a first thickness H1, and a second region 16 in which a pattern 162 as a second pattern made up of a plurality of recessed portions 23, which differ from the recessed portions 22 of the pattern 142 in at least one of interval and dimension, is made on the main surface 10 and which has a second thickness H2 different from that of the first thickness H1.
In this embodiment, as illustrated in
The template 1 may further include a third region 18 which is a region around the first and second regions 14 and 16. The template 1 is made of, for example, a Si-based substrate containing mainly Si. The shape of the template 1 as seen from the side of the main surface 10 is, for example, a 65 mm square.
In the first region 14, as illustrated in
As illustrated in
In the thick portion 140, the thickness between the main surface 10 and a back surface 12 of the template 1 is H1. The thickness H1 in this embodiment is the same as the thickness of the third region 18. This thickness H1 is, for example, 6 mm. The thick portion 140 is formed in a region in which the pattern is dense. It is to be noted that the thick portion 140 may have a thickness different from that of the third region 18.
In the thin portion 160, the thickness between the main surface 10 and the back surface 12 of the template 1 is H2. This thickness H2 is less than H1. The thin portion 160 is formed in a region in which the pattern is sparse. The thickness H2 is, for example, 1 mm.
The back surface 12 of the template 1 is formed by mechanical processing using a cutting machine, or formed by processing using sandblast, or the like.
As illustrated in
The third region 18 is a region in which, for example, a chuck configured to hold the template 1 is placed. The chuck comes in contact with the template 1, and then produces a vacuum between the contacted portion and the template 1 to hold the template 1.
Hereinbelow, a description will be given of a method of manufacturing the template 1 according to this embodiment.
a) through 2(f) are process drawings of a template manufacturing method according to the embodiment. Initially, as illustrated in
Next, as illustrated in
Specifically, initially, layout data of patterns to be formed on the template 1 is input to a cutting machine. The layout data may be stored in advance in the cutting machine, and may also be acquired from the outside. Subsequently, the cutting machine calculates a dense region and a sparse region based on the input layout data, and determines the layout of the back surface 12 based on the calculated sparse region and the dense region. The calculation of a dense region and a sparse region may be performed for each of blocks classified by function, such as a control unit and a storage unit. In addition, the layout of the back surface 12, instead of being calculated from the layout data, may be stored in advance in the cutting machine and may also be acquired from the outside. It is to be noted that while the layout of the back surface 12 is determined from two regions, a sparse region and a dense region, in this embodiment, the way of determining the layout of the back surface 12 is not limited to this. The two regions are divided into more regions, and the thickness of the template 1 may be varied stepwise. In addition, the cutting depth (the predetermined depth) can be determined depending on the pattern density formed in a region. For example, the lower the pattern density of a region, the deeper the region may be cut such that the thickness of the region is more decreased.
Next, as illustrated in
Next, as illustrated in
Next, as illustrated in
Next, the metal film 102 is etched with the resist pattern 106 used as a mask by a RIE (Reactive Ion Etching) method or the like, and the resist pattern 106 is removed.
Next, as illustrated in
Thereafter, the metal film 102 is removed, so that the template 1 is obtained.
The foregoing template manufacturing method is a method of manufacturing the template 1 used for an imprint process. However, the foregoing method may be used as a method of manufacturing a parent template. The parent template has, for example, a reversed pattern in which the pattern of a child template used for an imprint process is reversed. A method of manufacturing a child template from a parent template is performed, for example, in the following way. Initially, the reversed pattern of the parent template is pressed against a mask film (such as a resist film) formed on the child template, so that the reversed pattern is transferred to the mask film. Next, using the mask film after the transfer as a mask, a hard mask film (such as a chromium film) is formed. Next, using the hard mask film as a mask, the main surface of the child template is etched, so that the child template is obtained. It is preferable that the back surface of the child template be formed before the transfer pattern of the parent template is transferred. One reason for this is that this prevents adverse effects on the pattern due to vibrations and the like caused by cutting with use of a cutting machine.
Hereinbelow, a description will be given of a semiconductor device manufacturing method using the template 1 manufactured by the foregoing template manufacturing method. The template 1 is assumed to be attached to a semiconductor manufacturing apparatus.
a) through 3(d) are process drawings of a semiconductor device manufacturing method according to the embodiment. In
Initially, a semiconductor substrate 30 on the surface of which a resist film 32 is formed is prepared. The resist film 32 is formed of, for example, an ultraviolet curing resist which is to be cured by irradiation with ultraviolet rays. This ultraviolet curing resist is a resist having high liquidity. It is to be noted that the resist film 32 may be formed on a film being processed which is formed on the semiconductor substrate 30.
Next, as can be seen from
Next, as illustrated in
In the first region 14, assuming that the pattern 142 is divided into a center portion 144 and peripheral portions 146 and 148 positioned around the center portion 144, the center portion 144 protrudes farthest from the main surface 10. A distance T1 illustrated in
In the second region 16, assuming that the pattern 162 is divided into a center portion 164 and peripheral portions 166 and 168 positioned around the center portion 164, the center portion 164 protrudes farthest from the main surface 10. A distance T2 illustrated in
Here, one reason for causing the first and second regions 14 and 16 of the template 1 to flex is as follows. If the template 1 is pressed against the resist film 32 without causing the template 1 to flex, air becomes likely to be accumulated in the recessed portions 22 and 23 of the patterns 142 and 162. This makes it difficult to completely fill the recessed portions 22 and 23 with a resist. To overcome this difficulty, the patterns 142 and 162 are caused to flex for the recessed portions 22 and 23 to be curved. As a result, air is less likely to be accumulated in the recessed portions 22 and 23, which makes it easy to completely fill the recessed portions 22 and 23 with the resist.
Next, as illustrated in
Next, as illustrated in
Next, as illustrated in
Here, in cases where the thicknesses of the template 1 vary from the center toward the outer periphery, or from the outer periphery toward the center, regardless of the densities of patterns, a great force can be exerted on the transferred resist pattern 34 at the time of separation of the template 1 and the resist film 32. The great force arises from a force associated with movement of the template 1 and from a reaction force by which the template 1 attempts to return to its original shape. Due to the exerted great force, there is a high possibility of causing a defect in the resist pattern 34.
On the other hand, in cases where the template 1 is used in which the thick portion 140 and the thin portion 160 are formed in accordance with the densities of patterns as in this embodiment, when separation of the template 1 and the resist film 32 is made, flexures having amounts in accordance with the densities of patterns occur in the template 1. Due to the flexures, first, the peripheral portion 146 of the thick portion 140 and the peripheral portion 166 of the thin portion 160 are separated from the resist film 32 sequentially from one side surfaces of the recessed portions 22 and 23 (side surfaces close to the outer periphery of the template 1). Further, as the separation progresses, the peripheral portions 148 and 168 near the center of the template 1 are separated, prior to the center portions 144 and 164, from the resist film 32 sequentially from one side surfaces of the recessed portions 22 and 23 (side surfaces on the side of the boundaries of the first and second regions 14 and 16). As the separation further progresses, the center portions 144 and 164 are separated from the resist film 32 and, as a result, the template 1 is completely separated from the resist film 32. In such a manner, in the case of using the template 1 according to this embodiment, separation of the template 1 and the resist film 32 is not made at one time but is made gradually. Consequently, the force exerted on the resist pattern upon separation is small compared to the case of not forming the thick portion 140 and the thin portion 160. As a result, defect occurrence is suppressed as much as possible, so that the good resist pattern 34 is obtained.
In addition, the thicknesses of the template 1 vary in accordance with the densities of patterns, and therefore the reaction forces of the template 1 are also in accordance with the densities of patterns. For this reason, the speeds of separation vary in accordance with the densities of patterns, and therefore the good resist pattern 34 is obtained.
As described above, with the template 1 according to the embodiment, the defect in pattern shape can be suppressed. That is, according to the above template 1, separation of the template 1 and the cured resist film 32 is gradually made compared to the case of not forming the thick portion 140 and the thin portion 160. Therefore, the force required for separation becomes smaller, which suppresses the defect in pattern shape. Thus, the good resist pattern 34 can be obtained. In addition, according to the above template 1, the reaction forces of the template 1 are in accordance with the densities of patterns, and therefore the speeds of separation vary in accordance with the densities of patterns. Thus, it is possible to suppress the defect in pattern shape to obtain the good resist pattern 34.
With the above template 1, the recessed portions 22 and 23 are more likely to be completely filled with the resist film 32 compared to the case of not forming the thick portion 140 and the thin portion 160. This enables the good resist pattern 34 to be obtained. In addition, with the above template 1, the thick portion 140 and the thin portion 160 are formed, and therefore flexures having amounts in accordance with the densities of patterns occur in the template 1 to improve the speed of filling the resist film 32, so that the throughput of manufacturing semiconductor devices improves.
Moreover, with the above template 1, the good resist pattern 34 is obtained, and therefore the yield of semiconductor devices improves.
Modifications of the invention will be described below.
The template 1 illustrated in
The template 1 illustrated in
The template 1 illustrated in
The template 1 illustrated in
The region 14a is a region near the center of the template 1 according to this modification, and a thick portion 140a is formed in this region. In the region 14a, a pattern 142a made up of a plurality of recessed portions 22a is formed on the main surface 10.
The region 16a is provided adjacent to the region 14a, and a thin portion 160a is formed in the region 16a. Formed in the region 16a is a pattern which is sparse compared to the pattern 142a of the region 14a. In the region 16a, a pattern 162a made up of a plurality of recessed portions 23a is formed on the main surface 10.
The region 16b is provided adjacent to the region 14a, and a thin portion 160b is formed in this region. Formed in the region 16b is a pattern which is sparse compared to the pattern 162a of the region 16a. In the region 16b, a pattern 162b made up of a plurality of recessed portions 23b is formed on the main surface 10.
As can be seen from
The template 1 illustrated in
The template 1 illustrated in
The template 1 illustrated in
As described above, the resist on the substrate is filled into recessed portions, and passes through predetermined processes to form the resist pattern. At the time of separation of the cured resist and the template 1, the smaller the dimension of the recessed portion, the more the pattern defect is likely to be produced. Therefore, the template 1 according to this modification has the thick portion 140, at which the reaction force from the template 1 is smaller than that at the thin portion 160, in the first region 14 having the recessed portions 22 which are relatively small in dimension, and has the thin portion 160 in the second region 16 having the recessed portions 23 which are relatively large in dimension.
In the template 1 illustrated in
It is to be noted that while the thickness of the sparse region is small whereas the thickness of the dense region is large in the foregoing embodiment and modifications, the thicknesses are not limited to these. For example, based on the viscosities, wettabilities and the like of a film on which a pattern is to be transferred and a remover, the thicknesses may be such that the thickness of the sparse region is large whereas the thickness of the dense region is small.
Also in the foregoing embodiment and modifications, both the recessed portions 22 and 23 have rectangular cross-sectional shapes. However, their cross-sectional shapes are not limited to these shapes, and may be different from each other.
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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2010-66517 | Mar 2010 | JP | national |