Modelling of solid-state and excimer laser processes for 3D micromachining.

Holmes A.S., Onischenko A.I., George D.S., Pedder J.E., "Modelling of solid-state and excimer laser processes for 3D micromachining", SPIE Proceedings vol. 5713, Proc. Photonics West LASE 2005, San Jose, USA, 22-27 January 2005, 180-189.

Abstract

An efficient simulation method has recently been developed for multi-pulse ablation processes. This is based on pulse-by-pulse propagation of the machined surface according to one of several phenomenological models for the lasermaterial interaction. The technique allows quantitative predictions to be made about the surface shapes of complex machined parts, given only a minimal set of input data for parameter calibration. In the case of direct-write machining of polymers or glasses with ns-duration pulses, this data set can typically be limited to the surface profiles of a small number of standard test patterns. The use of phenomenological models for the laser-material interaction, calibrated by experimental feedback, allows fast simulation, and can achieve a high degree of accuracy for certain combinations of material, laser and geometry. In this paper, the capabilities and limitations of the approach are discussed, and recent results are presented for structures machined in SU8 photoresist.