Characterization of backside via hole etching of InP

摘要

Etching of InP was characterized for different process conditions in an ECR system. The etch rate increased with decreasing wafer size, increasing chlorine flow, increasing pressure, and decreasing hydrogen flow. The temperature of the wafer chuck, the argon flow, and the RIE rf power had little effect upon the etch rate. Optimum etch conditions were determined and a run at these conditions produced an etch rate of 4 #mu#m/min with less then 1percent of roughness at the bottom of the via hole. The results suggest an etching mechanism where the activation of chlorine is the rate limiting step. The addition of hydrogen is believed to reduce the amount of activated chlorine available for etching and thus reduce the etch rate. The temperature of the wafer surface was high enough that the volatility of the indium chloride was not the rate determining step.