SU-8胶微结构的尺寸公差研究

Study on Dimensional Tolerance of SU-8 Photoresist Microstructures

对SU-8胶微结构的尺寸及其公差进行了定量研究.在考虑了SU-8的吸收系数和折射系数对紫外光刻尺寸精度影响的基础上,根据菲涅耳衍射理论建立了紫外曝光改进模型和尺寸公差模型,对SU-8微结构的尺寸及其公差进行数值模拟.以硅为基底,进行了SU-8胶紫外光刻的实验研究.实验中掩模的特征宽度分别取50μm、100μm、200μm和400μm,SU-8胶表面的曝光剂量分别取400mJ/cm2和800mJ/cm2,测量了SU-8胶微结构的顶部线宽、底部线宽和SU-8胶的厚度,数值模拟结果与实验结果基本吻合.可以用本文的模型来预测SU-8微结构的尺寸及其公差.

This paper study the dimensions and tolerances of SU-8 photoresist microstructures quantitatively. A UV-exposure model and a dimensional tolerance model based on Fresnel diffraction theory are established by considering the impact of the refractive index and absorption coefficient of SU-8 photoresist on dimensional precision of UV-lithography. Two different experiments were done, in which the characteristic width of photo masks were 50μm, 100μm, 200μm and 400μm, respectively, and the exposure dose on the surface of SU-8 photoresist were 400 mJ/cm^2 and 800 mJ/cm^2. The top width, bottom width and thickness of SU-8 photoresist of microchannel cross section corresponding to the experiments were measured. Comparing the simulation results with experimental results, a good agreement between them is acquired. Based on the two models, the dimensions and tolerances of SU-8 photoresist microstructures can be predicted.