Effect of neutral beam etching on mechanical property of microcantilevers

Abstract

As an effective application of neutral beam etching (NBE) to microelectromechanical systems (MEMS), here we propose a combination of conventional plasma processes and NBE to remove plasma-induced damage. To evaluate the effect of the combined approach quantitatively, we measured the resonance properties of a microcantilever before and after NBE treatment and compared them with a characteristic quantity. The thickness of the damage layer times the imaginary part of the complex Young's modulus (δEds), which is a parameter of surface damage. Although a plasma process makes the damaged surface of the microcantilevers during their fabrication, the removal of that damage by NBE is confirmed as a reduction in δEds. NBE can provide a damage-free surface for MEMS devices without a high-temperature annealing process.

Mechanical quality factor enhancement in a silicon micromechanical resonator by low-damage process using neutral beam etching technology

“…These positive charges and interface traps may cause defects on the surface of the silicon device layer after the removal of SiO 2 by using HF solution. However, no damage is generated when neutral beam irradiation is employed due to the use of a high aspect ratio carbon aperture, as mentioned in [8,11,17,28]. Further investigation is needed to clarify the quantitative effect of NBE and DRIE on the surface damage of silicon resonators.…”