CF4+H20 Plasma ashing for reduction of contact/via resistance

摘要

The degradation of deposited low dielectric constant interlayer dielectrics and gap fill layers, such as HSQ layers, during formation of contacts/vias is significantly reduced or prevented by employing a plasma containing CF4+H2O to remove the photoresist mask and cleaning the contact/via opening after anisotropic etching. The CF4+H2O plasma also enables rapid photoresist stripping at a rate of about 10 to about 20 KÅ/min. Embodiments include photoresist stripping and cleaning the contact/via opening with a CF4+H2O plasma to prevent reduction of the number of Si-H bonds of an as-deposited HSQ layer below about 70%.