基于PDMS微结构模板转印技术的研究

Transfer Patterning of Microstructure with Polydimethylsiloxane Mold

基于界面间粘附能理论,结合有限元模拟研究聚二甲基硅氧烷(PDMS)微结构模板实现聚合物SU-8光刻胶的图形转移复制的转印机理,分析了微结构转印过程中基底表面能、压力和SU-8胶溶剂对图形转印的影响。结果表明,氧等离子体轰击基底表面可以有效提高基底表面能,保证大面积图形转印成功率;通过有限元方法分析PDMS模板上微结构在压强载荷下的变形情况,确定了保证转印精确度的最大压强载荷为60kPa;SU-8胶溶液中环戊酮的挥发会造成转印结构的收缩变形,足够大的SU-8胶浓度是保证转印精确度的前提,SU-8 2025光刻胶与环戊酮的体积比大于2时基本可以保证图形转印精度。

Here,we addressed the possible transfer mechanism of the SU-8 photo-resist patterns on polydimethylsi- loxane （PDMS） mold to the substmte, based on simulation in finite element method （FEM） and interracial adhesion theo- ry. The impacts of various factors, including the solvent of SU-8 photo-resist, surface energy of substrate and pressure ex- erted on the mold, on the pattern transfer were evaluated. The experimental results show that surface modification of the substrate with oxygen plasma significantly improved the transfer of large-area patterns, because of surface energy enhance- ment. The simulated results reveal that the optimized fidelity can be achieved at a maximum pressure of 60 kPa. In addi- tion, the volume ratio of SU-8 2025 photoresist to cyclopentanone higher than 2.0 ensures good fidelity, and avoids possi- ble shrinkage originated from volatilization of cyclopentanone in SU-8 photo-resist.