Abstract
The effect of the applying KOH wet etching on the fracture strength of a Si cantilever was studied, and the mechanism of the mechanical strengthening of it was investigated. The cantilever specimens that have the sidewall surface of Si{ 100} or Si{ 110} were produced by a Bosch process. A 50% KOH (40℃) chemical wet etching was applied to reduce the scalloping. The fracture stress in the both of Si{ 100} and Si{ 110} specimens increased with the advance of the etching. The obtained maximum fracture stress in Si{ 100} and Si{ 110} were 4.2 GPa and 3.7 GPa, respectively. We also observed the surface etched by Bosch process with Transmission Electron Microscope (TEM) to evaluate the thickness of the affected flow layer induced the process for the first time. The thickness of the affected flow layer was estimated less than 10 nm, even if it was existed. Thus, we concluded that the Bosch process in D-RIE does not introduce the affected flow layer on the etched surface.
