SPLAT, based on the Hopkins theory of partially coherent imaging, simulates two-dimensional projection-printing with partial coherence. The program is available in versions 3.0, 4.2, and 5.0. Version 3.0 is capable of modeling the effects of lens aberrations, apodizations, and modified illumination and can simulate the five primary lens aberrations: coma, astigmatism, distortion, spherical aberration, and curvature/defocus. Apodization schemes, such as the Hitachi spatial filter, can be added to the illumination system. Annular, off-axis, and quadrupole illumination sources can also be simulated.
For analysis of the resulting images, 2D or 3D image intensity data points are saved so that they can be used for 2D or contour plots on an X11 window or in PostScript. The 2D data points can also be fed into SAMPLE for simulation of processing steps based on that intensity profile. These files are compatible with DRAWPLOT and CONTOUR, which are on the cassette and tape distributions.
In version 4.2, modified illumination, in-lens filtering, true defocus, and magnification effects for high NA have been added. The user can specify the type of defocus, either true defocus or approximate defocus.
New in version 5.0 are the following: thin-film interference effects for calculating images within the photoresist, including reflections off the underlying thin-film stack, table-lookup of the pupil function to speed up the thin-film calculations, a link to the TEMPEST program output to model mask topography effects, representation of lens phase aberrations by up to 64 Zernike polynomials and phase maps from CodeV output, lens attenuation as a function of pupil position, plotting of the pupil function for output to PDRAW or PLOTMTV, aperture blocks, multiple off-axis annular illumination sources, and general illumination shapes with arbitrary intensities.
Documentation Included with the Program:
- D. Lee, Splat V5.0 User's Guide, (UCB/ERL M95/13, March 1995). Available separately for $5.00
Additional Documentation Available:
- P. D. Flanner III, Two-Dimensional Optical Imaging for Photolithography Simulation (UCB/ERL M86/57, July 1986). $10.00
- K. K. H. Toh, Two-Dimensional Images with Effects of Lens Aberrations in Optical Lithography (includes SPLAT 2.0 User's Guide) (UCB/ERL M88/30, May 1988). $10.00
- D. M. Newmark, Computer-Aided Design Tools for Phase-Shift Masks and Spatial Filtering (UCB/ERL M91/117, December 1991). $10.00
- D. C. Lee, Applying TCAD to Emerging Technologies, (UCB/ERL M95/38, May 1995). $7.50