AnisE is an easy-to-use anisotropic etch process simulation tool for MEMS design and process control
Demystifying etch behavior
Anisotropic etching is one of the most difficult silicon micro-machining processes to model, often considered in the realm of the black arts. It can be challenging to grasp intuitively due to the complex nature of evolving etch fronts. In fact, many companies have developed closely guarded etch secrets through trial-and-error experimentation.
Well, those days have ended. AnisE simplifies the process of accurately simulating etch behavior. Import your mask, choose your wafer orientation and your process parameters, and then watch the etch progress online before your eyes!
Unlike other tools that utilize heuristic methods to calculate propagation of etch planes, AnisE is a cellular automata based simulation. What does this mean? That other tools fail to provide accurate results for complex masks and long etch times. With AnisE, you can choose any mask configuration, however complex, throw in double-sided etching and add etch stops. Its easy
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AnisE at work
3D evolution of Silicon etch profiles generated by AnisE are shown in three cases. (a) evolution of three different corner compensation schemes (b) double sided etching of a silicon boss for a an accelerometer application and (c) multi-etch of silicon, an example where DRIE is followed by an anisotropic etch.
AnisE comes with built-in etch databases for KOH and TMAH. It automatically updates the etch rates as a function of temperature and concentration.
With AnisE, you can simulate single or double-sided <100> and <110> etching. You can incorporate multiple etch stops, steps or anything else you can do in the real world. In addition, you can study the effect of mask misalignment, the effect of combining RIE etching with anisotropic etching and many other real- world conditions.
Whether you are interested in studying process variation or designing corner compensation features, AnisE will become an invaluable part of your process toolset.
AnisE is capable of predicting the effects of etchant temperature, concentration, and etch time on the final 3D device geometry. Corner compensation and process tolerances can be modeled and visualized with AnisE. Creating correct geometries based on proper etch parameters before entering a fabrication facility saves resources otherwise spent on multiple prototype iterations.
Screenshots & Movies
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By creating or importing a mask file, users can:
Simulate <100> or <110> wafer orientation etching
Simulate etching under different time, temperature, and concentration parameters
Access TMAH and KOH etch-rate databases, or use customized etch-rate data
Etch the top, bottom, or both sides of a wafer
Implement multiple protective etch stops
Perform multiple etchings with different masks on a single wafer
Study the effects of misalignments and other process deviations
Determine the effects of vertical etching coupled with anisotropic etching
Perform 3D geometric visualization and cross-sectioning
Take distance measurements on the etched wafer
Visualize and export 3D results in DXF and VRML formats