Simulation and pattern distortion analysis of UV-LIGA based on the partial coherent light theory

Structural accuracy is one of the most concerned issues in micro fabrication, for its significant impact on the system performance. In this paper, the pattern transfer accuracy in proximity UV-lithography is investigated according to the partial coherent light theory. Based on the complex degree of coherence for any two points on the mask plane, a mathematical model is constructed to analyze the propagation of mutual intensity from the mask to the internal photo-resist. The intensity distribution is calculated subsequently. And with the aerial image distribution, the 3D photo-resist profile is simulated. Then shape distortion is characterized, especially on the edge, the corner, and the sidewall angle of the profile. The theoretical model has given an effective way for the error analysis, and the experimental results have evaluated the theoretical simulation and revealed the validity of the method.