Dear Professor Judy, Gemac and the Technical University of Chemnitz has developed bulk silicon etch simulators (SIMODE & QSIMODE). With this tools it is possible to simulate etching under different times, temperatures, concentrations and wafer orientations. Amongst conventional simulators it is also possible to simulate the perforation of the wafer and the development of the etch relief afterwards, as well two-step etch processes with a change of the etch mask and/or the etchant between the two etch steps. The program S I M O D E is a simulation tool for the orientation dependent etching of crystalline masked wafers. The program uses polygons as input data, containing the information of the mask geometry. The input formats are an easy editing ASCII-Format for simple, as well as a DXF- and GDS2-interface for more complex mask geometries. The program can also process slited masks to define multi-window structures. Due to the time consuming 3-d- simulation, the whole simulation of the etch process is splitted into two subprocesses. At first the two relevant contours (upper and lower edge) are determined, which describe the etch relief significantly. At second the complete 3-dimensional relief is constructed using planes, which are defined by the polygon sides of the upper and lower edges and the used etchant. An own graphic format, the DXF-, GDS2- and IGES-Format are supported as an interface. Additionally, a graphic editor is included to provide an easy way for drawing mask geometries without using a standard CAD-tool. Q S I M O D E is an additional module of SIMODE to give the user the possibility to simulate the development of etch reliefs on a cross section through the wafer. This can be used to simulate details of the etch relief especially in the case that the wafer is perforated during a two-side etch process. Furthermore 2-step etch processes with change of the mask or the etchant between the two etch steps can be simulated. S I M O D E and Q S I M O D E is able to simulate the orientation dependent etch process of any crystalline material based on the described model. The etch conditions may be chosen freely. A service for the determination of rates for user specific etch behaviours is also provided. For more information please contact me or see our web-side http://gemac.c.ntg.de . Sincerly D. Zielke ----------------------------------------- Gemac mbH Matthesstraáe 53 09113 Chemnitz Germany Tel.: ++49 371 3377 131 Fax: ++49 371 3377 272 100144.2036@compuserve.com -----------------------------------------