Process for cleaning a semiconductor substrate after chemical-mechanical

Abstract

An improved method for removing residual slurry particles and metallic residues from the surface of a semiconductor substrate after chemical-mechanical polishing has been developed. The cleaning method involves sequential spray cleaning solutions of NH.sub.4 OH and H.sub.2 O, NH.sub.4 OH, H.sub.2 O.sub.2 and H.sub.2 O, HF and H.sub.2 O, and HCl, H.sub.2 O.sub.2 and H.sub.2 O. The cleaning sequence is: 1. A pre-soak in a spray solution of NH.sub.4 OH and H.sub.2 O; 2. Spray cleaning in a solution of NH.sub.4 OH, H.sub.2 O.sub.2 and H.sub.2 O; 3. Spray cleaning in a dilute solution of HF and H.sub.2 O; 4. Spray rinsing in DI-water. It is important that slurry particulates first be removed by NH.sub.4 OH, H.sub.2 O.sub.2 and H.sub.2 O, followed by spray cleaning in a dilute solution of HF and H.sub.2 O to remove metallic residues. The spray cleaning method is superior to brush cleaning methods for both oxide-CMP and tungsten-CMP and results in superior removal of slurry particles and metallic residues introduced by the CMP processes. An optional spray cleaning step using a solution of HCl, H.sub.2 O.sub.2 and H.sub.2 O results in further reduction of metallic residue contamination following oxide-CMP. Compared to traditional brush cleaning the new spray cleaning process has a 2.times. improvement in throughput, less consumption of DI water, and low risk of cross-contamination between sequentially cleaned substrates.