IMPACT OF THE ELECTROCHEMICAL PROPERTIES OF SILICON-WAFER SURFACES ONCOPPER OUTPLATING FROM HF SOLUTIONS

The impact of light on the copper outplating from aqueous 0.5% HF solu tions on 10-20 Ohm cm (100) silicon wafers is investigated. Illuminati on is found to drastically increase the copper deposition. A model bas ed on the semiconductor properties of the silicon substrate which desc ribes the copper plating onto silicon is proposed. It is found that th e copper deposition onto these silicon surfaces is limited by the mino rity carrier supply at the wafer surface.