Patent ID: 7704306

Claim:
A method of preparing an aqueous electroless deposition composition for electrolessly depositing Co or a Co alloy onto a substrate in manufacture of microelectronic devices, the method comprising: treating water with a deoxygenating treatment to yield treated water having an oxygen concentration below 2 ppm; adding a source of Co 2+ ions, a B-based or P-based reducing agent, and a complexing agent to the treated water to yield an aqueous electroless Co deposition composition comprising at least about 0.5 g/L Co 2+ ions and an oxygen concentration no greater than 2 ppm; and incorporating an oxygen scavenger into the electroless deposition composition wherein the oxygen scavenger is selected from the group consisting of SO 3 2− , HSO 3 − , hydroquinone, catechol, resorcinol, and combinations thereof.