Damage-Free Ultradiluted HF / Nitrogen Jet Spray Cleaning for Particle Removal with Minimal Silicon and Oxide Loss

Abstract

There has been a trade-off between efficient particle removal and damage minimization to fragile device structures when using mixed-liquid/gas jet spray cleaning of silicon wafers. We have developed an ultradiluted HF/nitrogen jet spray cleaning procedure for single-wafer spin-cleaning, which can efficiently remove particles on both silicon and silicon-dioxide surfaces even at a low nitrogen flow rate without causing damage to fragile 45-nm polysilicon gate structures in a short period. The use of ultradiluted HF can make silicon and oxide loss negligible, below 0.003 nm and 0.03 nm, respectively. This very simple single-step cleaning procedure drastically reduces chemical consumption.