针对用于厚层光刻的重氮萘醌类正性光刻胶,利用动力学模型,分析了光化学反应速率的影响因素;给出了光化学反应速率明显受光强变化的影响以致互易律失效的原因。对厚度24gm的光刻胶AZ P4620在相同曝光量而光强分别为3.2mW/cm^2和0.63mW/cm^2的条件下进行了数值模拟和实验。当曝光光强为3.2mW/cm^2时仅需300s,即可显影完全,而当曝光光强为0.63mW/cm^2时需要的时间长达2400s,才显影完全,且面形轮廓差异较大。因此,在厚胶光刻中,当曝光光强较大时应适当减小曝光量,反之,应适当增加曝光量。
Lithography technology for thick film photo-resists is a much more complicated process. The mechanism of exposure for the thick DNQ-Novolak-based photo-resists is discussed in detail, and then the effect of exposure intensity on the photochemical reaction speed is investigated by using kinetic model. Numerical simulation and experiments show that the simulated results are consistent with those from experiments. For the lithography of thick DNQ-Novolak based resists, the photochemical reaction speed is obviously affected by the intensity magnitude during exposure, which will lead to exposure reciprocity failure. The cause originates from increase in temperature of resists, due to the highly exothermic reaction during exposure. These results are useful for the lithographic process optimization of thick film photo-resists.