热压印聚合物成型体脱模过程中接触脱离分析

Contact Detaching Analysis of Imprinted Polymers During Demolding in Thermal Imprint Lithography

热压印光刻技术中,聚合物成型体在脱模阶段的变形破损关系到压印质量的高低。为了提高热压印质量,研究脱模过程中模板和聚合物成型体之间的接触力变化至关重要。采用理论分析、模型试验和有限元法数值模拟分析热压印脱模中的接触脱离过程,得到不同脱模位移的等效应力云图和脱模接触力变化曲线。结果显示:脱模过程中聚合物微结构的根部和顶部边缘有应力集中和变形现象,通过计算聚合物根部节点和顶部节点的接触力大小,得出接触力峰值是聚合物出现应力集中和变形的原因。实际脱模操作时应加强对聚合物成型体根部和顶部边缘的保护,通过增涂低表面能的抗粘剂降低模板和聚合物成型体间的脱模接触力,达到减少压印缺陷、提高压印质量的目的。

The imprinting quality in thermal imprint lithography is influenced to a large extent by the deformation and damage of the imprinted polymers during demolding.Therefore,it＇s imperative to investigate the change of contact force between molds and polymers in the demolding process.In this paper theoretical analysis,model test and finite element method were used to simulate the contact detaching process of the thermal imprint lithography so as to obtain the equivalent stress nephograms and demolding contact force curves of different demolding displacements.The results indicate that stress concentration and deformation occurred at the root and top edges of the imprinted polymers＇ micro-structure and by calculating the contact force of polymers＇ root and top nodes it is found that stress concentration and deformation were caused by the peak value of the contact force.Thus,in actual demolding operation,measures should be taken to protect the root and top edges of polymers.To reduce the imprinting defects and improve the imprinting quality,low surface energy anti-adhesive films can be added to reduce the contact force between molds and polymers.