[mems-talk] TMAH Etching Silicon - loading effects

[Staller, Steven E]

We believe we have observed a strong correlation of <100>:<1111> selectivity to loading.

When we etch one wafer we get about &#189; the selectivity as we do when we etch 25 or more.

Is this a known phenom? Should we expect the selectivity to be effected this dramatically?

We are talking about selectivities of >65:1 vs ~30:1.

Steve