Pre-metal clean optimization for cluster defect prevention

Pre-metal clean is a critical procedure before the metal loop in the salicide process. Surface defects such as the surface native oxide or any other contamination may result in a poor adhesion of Ti/TiN, for example, and hence the poor salicide formation. HF treatment with IPA dry is a widely used methodology for surface defect removal, and results in a clean surface which is water spot free and has less chemical oxide. However, a cluster type defect is an accompaniment of this treatment in the salicide process. The aim of this work is to provide an optimized cleaning procedure at pre-metal clean for mass production.