Study of the cross contamination effect on post CMP in situ cleaning process

[Display omitted] •Brush itself caused cross contamination to wafer in post CMP in situ cleaning.•Brush rotational speed is the key parameter to control cross contamination.•Fluid (DIW) flow rate does not much influence on cross contamination. Scaling of gate lengths has led to significant improvement in semiconductor device performance. However, fabrication complexities have also increased and surface defects control becomes very critical for yield enhancement. In particular, chemical mechanical polishing (CMP) process is considered as one of the dirtiest processes to wafer surface contamination. And brush scrubber is the most effective method for post CMP in situ cleaning. Many literatures have reported brush scrubber mechanism and proposed particle removal efficiency based on remaining particles at post brush scrubber cleaning. However, concerns associated with brush to wafer surface contamination have not been addressed properly although real manufacturing has a lot of issues on that effect. This paper discuss cross contamination at brush scrubber process and emphasize that optimum cleaning should consider brush cross contamination in addition to brush particle removal efficiency.