Athena Guide : Grid :A finer grid should exist in those areas of the simulation structure where ion implantation will where p-n junction will be formed, or where optical illumination will change photoactive component concentration. The number of arithmetic operations necessary to achieve a solution for processes simul using the finite element analysis method could be estimated as ( N p ) α , where α is of order 1.5 - 2.0 and Np is number of nodes. Photo lithography 6.25: ILLUM.FILTER ILLUM.FILTER specifies the illumination source shape and illumination source filtering in OPTOLITH . Syntax ILLUM.FILTER [CIRCLE|SQUARE|GAUSSIAN|ANTIGAUSS|SHRINC] [GAMMA=<n>] [RADIUS=<n>] [ANGLE=<n>] [SIGMA=<n>] [IN.RADIUS=<n>] [OUT.RADIUS=<n>] [PHASE=<n>] [TRANSMIT=<n>] [CLEAR.FIL] CIRCLE|SQUARE|GAUSSIAN|ANTIGAUSS|SHRINC . : shrinc . Gamma : . Gamma=0 . Radius : shrinc . . Angle : shrinc . sigma : (filling factor) (illumination & projection) shrinc . in.radius & out.radius : . Transmit Phase . clear.fil : rese t . Example The following example defines a SHRINC illumination source, where the quadruple circular illuminatio sources are located at 45° to the x-axis with the center at a radius of 0.2 from the origin and a SIGMA =0.2 . ILLUM.FILTER SHRINC RADIUS=.2 SIGMA=.2 ANGLE=45 ILLUMINATION ILLUMINATION specifies the basic illumination parameters in OPTOLITH . Syntax ILLUMINATION [I.LINE|G.LINE|H.LINE|DUV.LINE|LAMBDA=<n>] [X.TILT=<n>][Z.TILT=<n>] [INTENSITY=<n>] Illumination : OPTOLITH . I.LINE|G.LINE|H.LINE|DUV.LINE : ... .