FIB vs Cleaving Methods for Blanket Al Thickness Measurement on Wafers

摘要

A study was done on the sample preparation methods for physical measurement of blanket Al thickness deposited on a wafer. Cleaving and Focused Ion Beam (FIB) methods were employed as the sample preparation methods for this study. Two wafers deposited with blanket tri-metal stack layers were fabricated, Wafer A with the exposed tri-metal stack layers (Ti/TiN, AI, Ti/TiN) and Wafer B with an additional 5000Å oxide layer passivated over the same blanket tri-metal stack layers as Wafer A. It was found that one of the FIB methods is proper for measurement of blanket Al thickness on the wafer. The results also show that there is a correlation between the Al thickness measured between samples prepared by cleaving and by FIB method.