Novel post treatment process to enhance spin-on carbon film properties

Carbon rich hard masks used in lithography processes play a vital role in pattern transfer to the desired substrate. Spin-on Carbon (SOC) film is one of the carbon rich hard masks which are an increasingly key component of the semiconductor fabrication process. SOC films are strongly required to improve the resist selectivity to under-layer for etch step. Furthermore, as device architectures become increasingly complex and fine pitch, hard masks material need to improve the further etch resistance for under layer etch. In response to the need for high etch resistant underlayers, the developments of SOC materials are desired. We focused on a processing optimization; we considered a novel post-treatment process to enhance physical properties of SOC films applying a plasma treatment. In this paper, the proposed plasma treatment process method, result of several film property data and quality of pattern transfer to under layer for narrow pitch was demonstrated. The plasma treatment process showed higher etch resistance, higher film density and higher hardness than conventional process while maintain the gap-filling. Furthermore, applying of plasma treatment process to Chemical Amplified Resist (CAR) film and Metal Oxide Resist (MOR) film also showed to improve Line and Space (LS) pattern shape and their defectivities.