An efficient volume-removal algorithm for practical three-dimensional lithography simulation with experimental verification

• Published in: IEEE transactions on computer-aided design of integrated circuits and systems 1993-09, Vol.12 (9), p.1345-1356
• Main Authors: Scheckler, E.W., Tam, N.N., Pfau, A.K., Neureuther, A.R.
• Format: Article
• Language: English
• Subjects: Applied sciences; Computational modeling; Computer science; control theory; systems; Equations; Etching; Exact sciences and technology; Optical materials; Optical refraction; Proximity effect; Resists; Simulation; Software; Workstations; X-ray lithography
• ISSN: 0278-0070; 1937-4151
• DOI: 10.1109/43.240082

A fast three-dimensional volume removal algorithm for resist dissolution is presented and verified with applications to optical lithography with phase-shift masks, resist silylation, and electron-beam lithography. Memory requirements are reduced by dynamically allocating complete topography and material information only at surface cells, and setting other cells as either bulk material or developer. The dissolution algorithm uses a fixed time step and stores the volume of material remaining in the surface cells. A simple redistribution scheme is used if more volume would be removed from a cell in one time step that is currently present. The compactness and speed of the algorithm make it suitable for use on engineering workstations. Simulations requiring 100*100*100 cells can be performed in a few minutes. Theoretical defocus effects in phase-shift mask lithography and shot-size error in electron-beam lithography are compared with experiment. A dry-etch resist silylation process is also investigated.< >