Investigation of the oxidation behaviour of thin film and bulk copper

The paper reports the use of self-assembled monolayers (SAMs) of dithiols to induce electroless copper deposition on a gold substrate. The metallization catalyst, palladium nanoparticles, is bound on the dithiol SAM. The assembly process is followed by IR and X-ray photoelectron spectroscopies to confirm the formation of a monolayer with bound catalyst. Electroless metallization is then carried out with a steady deposition rate of 130 nm/min. Additionally, microcontact printing of the catalyst on the SAM by poly(dimethylsiloxane) stamps is used to localize copper deposits. Resulting metallization is selective and allows for a high resolution.

Selective Electroless Copper Deposition on Self-Assembled Dithiol Monolayers

https://www.webpages.uidaho.edu/nanomaterials/research/Papers/Barriers/Ti/Microelectronic%20Engineering%2050%20(2000)%20pp%20473-479%20%20Room%20temperature%20electroless%20plating.pdf

Room temperature electroless plating copper seed layer process for damascene interlevel metal structures

Copper is deposited on TaN and WN barrier layers by electroless plating without the need for activation preprocessing when substrates are (i) pretreated by wet chemical etching to remove surface oxides, and (ii) immersed in an electroless Cu plating solution containing glyoxylic acid as a reducing agent Electrical potential measurements indicate that the redox potentials of TaN and WN in the plating solution are lower than that of copper, driving displacement plating of Cu in the initial stage of deposition The adhesion between electroless-plated Cu and the TaN barrier layer after annealing is 011 kgf/cm as determined by a peeling test, which is sufficient for reliability during chemical mechanical polishing A damascene Cu interconnect was successfully fabricated without delamination and exhibited an electrical resistivity of 22 μΩ cm after annealing for a 042 μm wide interconnect track These results indicate that the proposed electroless process is suitable for the formation of a Cu seed layer prior to electrodeposition for the fabrication of ultralarge scale integrated interconnects © 2003 The Electrochemical Society All rights reserved

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Electroless Plating of Copper on Metal-Nitride Diffusion Barriers Initiated by Displacement Plating

Borane-based electroless plating baths are of interest in many microelectronics applications such as barrier and capping layers for copper integrated circuit interconnect. To optimize the plating baths a thorough understanding of the role of the bath constituents is required. To this end we have employed microelectrodes to investigate the oxidation mechanism of boranes in alkaline solutions. In this paper we present data for the simpler ammonia borane (AB) oxidation and compare it with the previous analysis of dimethylamine borane (DMAB) oxidation. Both AB and DMAB are shown to oxidize in two steady-state mass transport-controlled oxidation waves for specific concentration ranges. Particular emphasis is placed on the analysis of the second oxidation wave observed at less negative potentials and the differences observed in the analysis of AB and DMAB in this potential region. The potential range for oxidation, the optimum concentration, and a suggested mechanism for oxidation are shown.

G.M. Crean

Papers

Electroless copper metallisation of titanium nitride