3D Anisotropic-Etching Simulator FabMeister-ES
Crystal orientation-dependent anisotropic etching is a phenomenon in which the etching rate of a single crystal differs substantially with the crystal orientation. The fabrication technique making use of this phenomenon has been applied to the fabrication of structures of physical sensors such as pressure sensors and velocity sensors consisting of single crystal silicon. Recently, by means of this technique, it has been required to fabricate even more complicated 3D device structures, such as the head of an ink jet printer, on a single-crystal silicon substrate. Accordingly, it becomes difficult to design the fabrication process with only the knowledge that the etching rate in a specific direction is smaller than those in other directions. Specifically, there is a need for a high-level mask pattern design to compensate the undercut of the etching mask, formation of a complex curved surface by several stages of etching, and process to etch through the substrate from both side of substrate. Further, the anisotropic etching characteristics are significantly influenced by concentration and temperature of etching solutions such as KOH and TMAH. Therefore, appropriate selection of the etching conditions is an important factor to determine the success or failure of the fabrication process. However, in practice, the selection of the process conditions is taken over within each organization as "know-how". The methodology has not been established.
The present FabMeister-ES system has been in development with a view to replacing the traditional empirical and trial-and-error design of MEMS fabrication on a silicon substrate with bulk micromachining based on intelligent computer design. The fundamental function lies in analytically predicting the temporal variation of the 3D etching profile in the chemical anisotropic etching.
It is designed to handle wafers having an arbitrary surface orientation and an arbitrary mask pattern and to allow an analysis considering the effects of the concentration and temperature of etching solutions such as KOH and TMAH with different etching characteristics.
Etching rate database
This database is equipped with data on the etching rate for all crystal orientations of silicon when KOH and TMAH solutions are used.
The analysis results on the etching profile are output with IGES and AVS format.
Department:Science Solutions Division