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1991
Journal Article
Titel
Simulation of defects in 3-dimensional resist profiles in optical lithography
Abstract
One important use of process modeling in research and manufacture of semiconductor devices is to optimize the performance of an optical lithography process for smaller dimensions. The production of semiconductor devices with submicron geometries requires the lithographic process in particular to be pushed to its physical limits. For the assessment of exposure equipment and resist material in optical lithography, two dimensional simulators, such as SAMPLE, have successfully been applied for a long time. In the course of VLSI evolution, however, strong needs have been arising for simulator tools capable of fully covering 3-dimensional aspects. This is primarily caused by the fact, that edge effects, optical proximity effects and the influence of defects can no longer be neglected in highly densified pattern geometry with poor symmetry, such as in highly integrated DRAM cells with cell sizes of 4-6 myqm. In the case if high numerical aperture projection optics the above mentioned effects become extremely critical, since they are coupled with focus effects. The situation becomes even more severe, if the lithographic operation is to be performed on a non-planar topography.