Evaluation Method of "Formablity" in Nano/Micro Processing and Its Application to Inprint Lithography

提出了一种独立于现有成形方法的“可成形性”概念，它代表了成形的基本可能性。这个想法可以用来评估为生产新产品而开发一种新的成形技术的努力有多大的实际可能性。在本研究中，我们开发了一种定性和定量评价纳米/微加工“成形性”的方法，并将其应用于压印光刻，有望成为下一代新的成形方法之一。应用表明新方法的理论可能性和局限性如下：(1)压印中的“成形性”包括模具的可释放性和可转移性。根据分离开始的界面，模具可释放性被半定量地分为三个级别：模具/树脂之间的分离，树脂/树脂之间的分离和树脂/基之间的分离。模具可释放性的基本因素是树脂-模具与基树脂的黏结能之比和待成型形状的长径比。定量地说，当树脂-模具与基础树脂的黏结能之比小于等于1时，脱模是可能的。但是，在长径比较大的情况下，为了获得良好的脱模效果，应减小粘聚能比，因为粘聚能比与长径比成反比。(2)可转移性根据树脂脱模后的变形程度，半定量地分为三个等级。这种可转移性取决于能量比（B/A）和长径比（E/D），其中“A”是树脂的黏结能，“B”是树脂和模具之间的黏结能，（E/D）是要形成形状的长径比。可转移性好的定量条件是（E/D）【小于或等于】- 4x (B/A)+3，而（E/D）【大于或等于】- 4x (B/A)+4，不可能从模具转移到树脂。

An idea of "formability" which stands for fundamental possibility of forming and is independent of existing forming methods has been proposed. This idea can be used to evaluate how much the effort to develop a new forming technique for producing new products has practical possibility. In this study, we have developed a method of qualitative and quantitative evaluation of the "formability" in nano/micro processing and we have applied it to inprint lithography that is expected to be one of the new forming methods in the next generation. The application has clarified theoretical possibility and limits of the new method as follows :(1)"Formability" in inprint lithography consists of mold releasability and transferability. Mold releasability is, semi-quantitatively, classified into three levels depending on interfaces where separation begins : separation between mold/resin, separation between resin/resin and separation between resin/base. The basic factors for mold releasability are the ratio of cohesive energy of resin-mold to base-resin and the aspect ratio of a shape to be formed. Quantitatively, mold release is possible when the ratio of cohesive energy of resin-mold to base-resin is less than or equal to 1. However, in case of large aspect ratio, the ratio of cohesive energy should be decreased for condition of good mold release, because the ratio is in inverse proportion to the aspect ratio.(2)Transferability is, semi-quantitatively, classified into three levels based on the degree of deformation of resin after mold release. This transferability depends on the energy ratio (B/A) and the aspect ratio (E/D), where 'A' is cohesive energy of resin, 'B' is cohesive energy between resin and mold, and (E/D) is the aspect ratio of a shape to be formed. Quantitative condition for good transferability is(E/D)【less than or equal】-4×(B/A)+3,while for(E/D)【greater than or equal】-4×(B/A)+4,transfer from mold to resin is impossible.