光刻胶掩膜材料超光滑表面切削

Ultra-precision cutting of photoresist mask for ultra-smooth surface

鉴于以光刻胶为代表的高分子材料的切削特性决定了掩膜微细结构的加工质量,以SU8为研究对象,结合实验和仿真分析研究了光刻胶掩膜的切削特性。通过纳米压痕法测试了光刻胶SU8的应力-应变关系,建立了基于能量法的SU8切削仿真模型,然后采用AdvantEdge FEM模拟了不同切削参数下光刻胶SU8的切削过程,最后开展了光刻胶SU8的超精密加工实验。结合仿真与实验结果,分析了切削参数和刀具前角对表面质量的影响规律,优化了光刻胶SU8的切削加工参数。结果表明:表面粗糙度随着切削速度的增大呈现减小的趋势,随着进给速度和切削深度的增加呈现增大的趋势;当切削速度为2.09 m/s、进给速度为1 mm/min、切削深度为2μm、刀具前角为0°时,光刻胶掩膜的表面粗糙度Ra达到最优为7.4 nm,无微裂纹等微观缺陷。基于切削仿真与实验结果对加工参数进行优化,并在光刻胶SU8掩膜上实现了高精度微透镜阵列结构的加工。

The cutting characteristics of the polymer determine the processing quality of the microstruc-ture.Considering photoresist SU8 as the representative polymer in this research,the cutting characteris-tics of the photoresist mask were studied through experimental analysis and simulations.The stress-strain relationship of SU8 was analyzed via the nanoindentation method,and a cutting simulation model of SU8 based on the energy method was established.Next,the cutting characteristics of SU8 under different cut-ting parameters were simulated using AdvantEdge FEM.Finally,an experiment involving ultra-precision machining of SU8 was performed.According to the simulation and test results,the effects of the cutting parameters and tool rake angle on the surface quality were analyzed,and the cutting parameters of SU8 were optimized.The results demonstrat that the surface roughness decreases with an increase in the cut-ting speed and increases with the feed rate and depth of cut.Within the scope of the experimental condi-tions,when the cutting speed is 2.09 m/s,the feed speed is 1 mm/min,the depth of cut is 2μm,and the tool rake angle is 0°;the surface roughness Ra of the photoresist reaches the optimum value of 7.4 nm,and there are no microfractures.Finally,according to the test and simulation results,the processing parame-ters were optimized,and a microlens array mask structure was fabricated on SU8 with high precision.