A novel numerical method for analyzing the deformation of molding patterns on UV imprint with soft molds considering thermal deformation in addition to UV shrinkage and curing is presented. In the case of UV imprint using an easily deformable mold-like PDMS, transfer error on UV resin is caused by thermal expansion/contraction arising from UV reaction heat and by UV shrinkage. Specifically, when a UV resin with high reaction heat such as cation polymerization-type UV resin is used, thermal deformation has a nonnegligible effect on pattern shape deformation. Therefore, it is necessary to consider thermal deformation caused by UV reaction heat in the numerical deformation analysis of UV imprint requiring high surface accuracy, such as optical devices. The present method newly adopts the theory of reaction rate to consider the temperature-dependent UV reaction rate and introduces an advanced idea of virtual temperature as a measure of UV reaction progress. By defining the time histories of thermal deformation and UV shrinkage as a function of virtual temperature, the effects of both are considered simultaneously. In order to apply the present method to actual imprints, temperature measurement experiments and various rheometry experiments are conducted on a target UV resin to identify its model parameters. A validation analysis of the present method is performed on an actual micromirror array imprint and shows that the simulation accuracy of transfer error can be significantly improved by considering thermal deformation.

中文翻译：

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考虑UV收缩和固化的热变形的UV压印图案形状变形的数值分析

提出了一种新的数值方法，该方法用于分析软模具在UV压印上成型图案的变形，并考虑到UV收缩和固化以外的热变形。在使用易于变形的模具状PDMS进行UV压印的情况下，UV树脂上的转印错误是由UV反应热引起的热膨胀/收缩和UV收缩引起的。具体地，当使用具有高反应热的UV树脂如阳离子聚合型UV树脂时，热变形对图案形状变形的影响不可忽略。因此，在光学器件等要求高表面精度的UV压印的数值变形分析中，有必要考虑由UV反应热引起的热变形。本方法新采用反应速率理论来考虑与温度有关的紫外线反应速率，并引入了虚拟温度的先进思想作为衡量紫外线反应进程的方法。通过定义热变形和UV收缩的时间历程作为虚拟温度的函数，可以同时考虑两者的影响。为了将本方法应用于实际压印，在目标UV树脂上进行温度测量实验和各种流变学实验以识别其模型参数。本方法的验证分析是在实际的微镜阵列压印上进行的，表明通过考虑热变形可以显着提高转印误差的仿真精度。