Method for forming an opening in polymer-based dielectric

摘要

A method for forming a damascene opening in a polymer-based dielectric layer is introduced. The method includes providing a substrate, which has also a conductive structure layer and a polymer-based dielectric layer formed thereon already. The polymer-based dielectric layer is uniformly hardened by a thermal treatment. A mask layer is formed on the polymer-based dielectric layer. The mask layer and the polymer-based dielectric layer are patterned to form an opening. The opening exposes a surface of the polymer-based dielectric layer. The exposed surface of the polymer-based dielectric layer is further hardened by a local hardening process. The local hardening process includes using an irradiation source of a high energy light beam, electron beam or ion beam to proceed the local hardening. The irradiation source can be incident onto the substrate by vertical angle or inclining angle. The substrate can also be rotated.