Hydrogen plasma effects on ultralow-k porous SiCOH dielectrics

Abstract

This study investigated the interactions of hydrogen plasmas with ultralow- k porous SiCOH (pSiCOH) films and their dependency on the values of the original dielectric constant, porogen used for the preparation of films, and substrate temperature during the plasma treatment. pSiCOH films of similar dielectric constants have been prepared by plasma-enhanced chemical-vapor deposition using an identical SiCOH skeleton precursor, but with two different organic porogens. The films exposed to the hydrogen plasmas have been characterized by optical techniques, shrinkage characterization, and electrical measurements. It was found that the hydrogen plasma modifies the structure of pSiCOH 's oxide skeleton and reduces the concentration of the Si- (CH3) 1 bonds, resulting in an increase of the dielectric constant. The degree of modification, for films prepared from the same precursors, is larger for films with lower dielectric constants (k) and is affected by the porogen used to prepare films with similar k values. © 2005 American Institute of Physics.