Control of Topographical Selectivity in Palladium-Activated Electroless Copper Metallization

From our study on copper electroless deposition, we have successfully controlled selective copper growing only in vias and trenches of TiN/SiO2/Si and Ta/SiO2/Si substrates by adapting the accelerating and inhibiting effects of additives and modulating the condition of palladium activation. 2,2'-Dipyridyl and polyethylene glycol play a significant role of inhibitor and accelerator, which contributed to the selective growing during the electroless deposition process. Furthermore, we found that the postcleaning conditions of deionized water rinsing and N2 blowing after Pd activation also strongly affects the topographical selectivity of copper growing in our electroless deposition.