Investigation on Fabricating High Aspect Ratio Microholes on Silicon by FIB/SEM Milling

Abstract

The aspect ratio of microholes milled on silicon by FIB/SEM milling was investigated with various beam currents and initial depths of mill. Lower beam current gives finer surface and more accurate structure. The results showed that the highest depth of microhole fabricated using FIB/SEM milling was 17.45µm, and maximum aspect ratio 1:8, without using gas injection system (GIS). The value of depth obtained was less than the initial depth of mill due to re-deposition, influenced by low sputter yield of silicon. Milling time and dwell time play important roles in milling process to get high aspect ratio of microholes.