TRAVIT: Examples of Simulations

Isotropic etch is normally a wet etch or a plasma etch without a physical component. In maskmaking, wet etch of quartz is one possible example of an isotropic etch.

Isotropic Etch

Most commonly, etch involves a combination of isotropic and anisotropic components. In this case, the resulting etch profile is more complex. Footing and micro-trenching are often noticeable.

Simulated etch profile of a trench Simulated etch profile

The linewidth may vary depending on the surrounding pattern. This effect is called microloading. In this example, lines and spaces of equal width were simulated. Next to a large pad, CD variation was found.


A simulation of the etch dynamics, including the CD variation and bias, helps to optimize the post-etch time for a specific etch process.

Etch optimization using TRAVIT