Using self-assembled monolayers for controlled electrodeposition of copper into submicrometer size surface features/decrements

• DOI: 10.1007/s10008-006-0096-0
• Publication Date: 2006-02-20T04:09:23Z
• Authors: Mikołaj Donten; Mateusz L. Donten; Zbigniew Stojek; Kazimierz Wikiel
• Keywords: 01 natural sciences; 0104 chemical sciences

This work presents the application of alkanethiols for selectively masking the main surface of copper-seed-layer-covered silicon wafer, as used for the microprocessor production. The target of the investigation was to deposit copper only in the trenches and vias (channels of various shape) of micrometer size and not over the entire surface as in the presently used methods. The procedure developed starts with filling the trenches and vias with water, which is followed by dipping the wafers in a hexane solution containing dissolved dodekanetiol. Alkanetiol adsorbs and self-organizes on copper not protected with water and blocks the electroreduction of copper ions from the bath. The trenches and vias are free from adsorbed alkanetiols due to their very limited solubility in water. The surface-blocking process works very well and may effectively simplify the copper electrodeposition for microelectronic applications. The selective electrodeposition of copper accomplished by the proposed method significantly reduces the problems associated with the removal of excess of copper from the processed circuit elements.