Deep Silicon Etching™

MEMS and nanotechnology applications frequently require features with relatively high aspect ratios and anisotropic profiles to be created in silicon. This is usually accomplished using the Bosch process, also known as deep silicon etching (DSE) or deep reactive ion etching (DRIE). DSE is one of the Plasma-Therm technologies available on the VERSALINE® platform.

The DSE process alternates between deposition and isotropic etching in a chamber with an inductively coupled plasma (ICP) configuration. A conformal polymer is deposited, and then 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 "scalloped" vertical sidewalls. However, with specialized hardware and software, rapid cycling between deposition and etching can be accomplished. “Fast switching” of power, pressure, and gases in each step can virtually eliminate scalloped sidewalls.

Plasma-Therm's DSE process modules have been demonstrated to have the widest process latitude, high mask selectivity, low SOI notching, and fast process switching. This has made Plasma-Therm the leader in DSE technology.