聚合物芯片复型模具的新型制作工艺研究

New Fabrication Process of Polymer Microchip Replication Mold

AZ4620是一种广泛应用于微系统制作的正性光刻胶。高温改性后的AZ4620在紫外曝光时光照部分不再发生光化学反应,基于这样的材料特性,以220℃高温硬烘30 min获得改性的无光敏性的光刻胶,通过Plasma氧刻蚀制作出底层结构,再在底层结构表面涂胶采用多次曝光和显影制作出具有三层微结构的光刻胶模具,利用模塑法制作聚合物PDMS芯片。对光刻胶高温硬固工艺进行分析,对产生回流、残余应力、气泡等问题进行理论分析和实验研究,优化了模具加工工艺。采用多次喷涂,Plasma氧处理改善浸润性,高温硬烘0.5℃/min的升温速率得到了质量较好的多层光刻胶模具,为利用正性厚胶制作多层微结构提供了新的方法。

AZ4620 is a broadband positive photoresist widely used for MEMS fabrications.It does not arouse photochemical reaction during UV exposure after thermal disposing modification.Based on this characteristic,a kind of bottom layer without photosensitivity was obtained by hard baking at 220 ℃ for 30 min,and then AZ4620 was used to fabricate photoresist mold with a multi-layered microstructure by Plasma oxygen etching and multiple exposure.The polymer PDMS microchip was made by plastic molding.Factors affecting the hard baking process,bubbles and cracks were analyzed theoretically and experimentally.By applying the methods of multiple spray coating,plasma oxygen treating and temperature ramping velocity at 0.5 ℃/min,a better photoresist mold was obtained.It provides a new method for multi-layered molding of thick positive resist which is propitious to the development of thick film photoresist process.