Development of electrochemical copper deposition screening methodologies for next generation additive selection

To reduce time-to-knowledge and costs associated with 300 mm wafer processing a laboratory-scale copper electrochemical deposition (ECD) system was developed for screening new organic additives which promote bottom up fill in interconnect trenches and vias. This new setup enables working process conditions and functionality trends to be identified for experimental suppressors and levelers at leading edge feature sizes (sub 50 nm). These results can then be transferred to the in-line copper plating tool for full wafer plating and further analytical testing. This paper presents results of a case study using both open source and proprietary chemistry, focusing on gap fill, throwing power, and mounding as performance metrics. Preliminary data on the transferability of process conditions to the full wafer tool are also presented.

Cross-sectional SEM images of 50 nm trenches plated in (a) beaker setup. (b) 300 mm plating tool (after CMP). The voids in the beaker-plated sample indicate that further improvements are needed; however, the fill in 60 nm trenches and larger was identical.Figure optionsDownload as PowerPoint slide