Megasonic Cleaning of Blanket and Patterned Samples in Carbonated Ammonia Solutions for Enhanced Particle Removal and Reduced Feature Damage

Abstract

An investigation of particle removal efficiency and feature damage has been conducted in NH 4 OH/NH 4 HCO 3 cleaning solutions irradiated with megasonic energy. By adjusting the pH of the solution in the range of 8.2 -8.5, high particle removal efficiency (PRE) was achieved while feature damage was reduced significantly. The sonoluminescence data collected from NH 4 OH and NH 4 OH/NH 4 HCO 3 solutions indicate significant suppression of transient cavitation in alkaline solutions containing aqueous CO 2 .Index Terms-Megasonic cleaning, particle removal efficiency (PRE), feature damage, CO 2 (aq.), sonoluminescence (SL)

Analysis of Sonoluminescence Signal from Megasonic Irradiated Gas-Containing Aqueous Solutions Using Replaceable Single-Band Filters

“…More recently, the authors of this paper reported the development of a formulation which takes advantage of the beneficial effect of CO 2 at slightly alkaline pH values (∼ 8.2) for high PRE (90%) while reducing feature damage. 29 SL measurement from that solution showed strongly suppressed signal with ∼ 130 ppm CO 2 (aq.) maintained in the solution.…”

Effects of Gas-Dissolved Water for Ceria Nanoparticles on the SiO2 Film Surface in Post-CMP Cleaning

“…66 Furthermore, Han et al suggested a formulation of NH 4 OH/NH 4 HCO 3 for CO 2 gas-generating alkaline cleaning solutions to prevent patterned wafer damage by decreasing sonoluminescence intensity caused by transient cavitation in megasonic cleaning. 67 Based on the literature, cavitations induced by CO 2 GDW would be decreased compared to those induced by H 2 GDW and O 2 GDW induced cavitations, relatively.…”

(Invited) Understanding and Controlling Electrochemical Effects in Wet Processing

“…In fact, dissolved carbon dioxide is very effective in suppressing transient cavitation, as may be evident from the absence of current transients. Particle removal with reduced damage to features has been shown to be possible using ammoniacal solutions containing dissolved CO 2 (8).…”