Superconformal Electrodeposition Using Derivitized Substrates
Thomas P. Moffat, Daniel Wheeler, C Witt, Daniel Josell
This paper demonstrates superconformal electrodeposition of copper in trenches using a two step process. The substrate is first derivitized with a submonolayer coverage of catalyst and then transferred for electroplating in a cupric sulfate electrolyte containing an inhibitor. For an optimum catalyst coverage, superconformal, bottom-up filling of trenches and vias is observed. If the catalyst coverage is too low or high, conformal or subconformal deposition occurs resulting in void formation during feature filling. The filling behavior of the derivitized electrodes is analogous with that obtained using a single (conventional) electrolyte containing both catalytic and inhibiting species. Restricting the catalyst to the surface by derivitization prior to metal deposition provides unambiguous verification of the curvature enhanced accelerator coverage mechanism (CEAC) of superconformal film growth. From a technical perspective, the two step process offers an interesting solution to the difficult control issues associated with catalyst destruction and related aging effects known to occur in the conventional single-electrolyte superfilling process.
, Wheeler, D.
, Witt, C.
and Josell, D.
Superconformal Electrodeposition Using Derivitized Substrates, Electrochemical and Solid State Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=853171
(Accessed October 3, 2023)