MASSIVELY-PARALLEL ELECTROMAGNETIC SIMULATION FOR PHOTOLITHOGRAPHIC APPLICATIONS

The two-dimensional massively parallel electromagnetic simulation prog ram TEMPEST has been generalized to extend its applicability to many o f the difficult problems in photolithography, metrology, and alignment , TEMPEST, which has been made available on the NCSA and other computi ng centers, combines together techniques for analysis of the transvers e electric (TE) and the transverse magnetic (TM) polarizations, obliqu e incidence, highly dispersive materials, and a technique for synthesi s of partially coherent optical images. The solution is based on the t ime-domain finite-difference method, but exploits the power of massive ly parallel computer architectures, Equations suitable for massively p arallel implementation are given for oblique incidence, both polarizat ions and dispersive materials. Computer time per iteration cycle is co nstant irrespective of the polarization and angle of incidence, Howeve r, the total simulation time for convergence was found to be dominated by physical scattering phenomena. Convergence for the TM polarization is 1.5 times slower than the TE polarization because of edge currents , and oblique incidence is 2 times slower than normal incidence owing to artificial reflection from the domain boundaries, A typical simulat ion time is three to five minutes with 256 k (1 k = 1024) simulation n odes on a CM-2 with 8 k processors. The effectiveness of the program f or photolithographic applications is demonstrated by considering the e ffects of subtle changes in phase-shifting mask topography on the opti cal images.