High-density plasma patterning of low dielectric constant polymers: A comparison between polytetrafluoroethylene, parylene-N, and poly(arylene ether)

The pattern transfer of SiO2 hard masks into polytetrafluoroethylene, paryl ene-N, and poly(arylene ether) (PAE-2) has been characterized in an inducti vely coupled plasma source. Selected results obtained with blanket parylene -AF4 films are included in this work. These dielectrics offer a relatively low dielectric constant (k similar to2-3) and are candidate materials for u se as intra- and interlayer dielectrics for the next generations of high-sp eed electronic devices. Successful patterning conditions were identified fo r Ar/O-2 and N-2/O-2 gas mixtures. It was found that the formation of strai ght sidewalls in Ar/O-2 discharges relies on the redeposition of oxygen-def icient etch products on the feature sidewall. Furthermore, the etch rates o f parylene-N, parylene-F, and PAE-2 for blanket and patterned films could b e captured by a semiempirical surface coverage model, which balances the ad sorption rate of oxygen and the ion-induced desorption rate of oxygenated e tch products. (C) 2001 American Vacuum Society.