Deep Silicon Etching™

MEMS and Nanotechnology applications frequently require features to be created in silicon with relatively high aspect ratios and anisotropic profiles. These objectives are usually accomplished using the Bosch process, also commonly known as Deep Silicon Etching (DSE) or Deep Reactive Ion Etching (DRIE). Plasma-Therm offers DSE technology on the VERSALINE platform.

The DSE process alternates between deposition and isotropic etching in a chamber with an ICP configuration. During the deposition process, a polymer is deposited such that it is conformal over the surface. Following deposition, the polymer is removed only from the horizontal surfaces, allowing isotropic etching during the next step. The deposition gas is typically C4F8 and the etching gas is commonly SF6.

The alternation of process steps can produce features with vertical profiles and sidewall morphology that often referred to as "scalloped." However, by using specialized hardware and software, switching between deposition and etching steps can be accomplished very quickly. With “fast switching” of power, pressure, and gases in each step, the scalloped effect can be virtually eliminated.

Plasma-Therm has developed DSE that has been demonstrated to have the widest process latitude. This process latitude, coupled with the high mask selectivity, low SOI notching, and fast process switching, has made Plasma-Therm the leader in providing DSE technology.

