Formation and Film Characteristics of Dual Damascene Interconnects by Bottom-up Electroless Cu Plating
- Kansai University, Dept. of Mechanical Engineering, Suita 3-3-35, Osaka (Japan)
- Shaanxi Normal University, School of Chemistry and Materials Science (China)
Bottom-up filling of Cu in a dual damascene interconnection structure was achieved through electroless plating alone. The addition of inhibitor molecules to the electroless Cu plating solution was investigated, and showed that sulfopropyl sulfonate (SPS) was highly effective in promoting bottom-up filling. Bottom-up filling was enhanced by shrinkage of the hole diameter, suggesting that the diffusion flux of SPS molecules to the bottom of the holes was suppressed. Thus, Cu deposition rate near the hole bottom was larger than that outside the hole, leading to bottom-up filling. The salient feature of electroless plating technology is the lack of overgrowth or bump formation after hole filling, which is a serious problem in electroplating technology. Problems such as increased resistance due to inclusion of SPS molecules and pattern size dependence affected applicability of this method. A two-step electroless plating using different concentrations of inhibitor molecules was effective for filling a dual damascene structure without voiding, and may provide a practical solution for ULSI interconnections.
- OSTI ID:
- 20798171
- Journal Information:
- AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 817; ISSN APCPCS; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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