title: Optical-gradient antireflective coatings for 157-nm optical lithography applications.
abstract: We demonstrate an optical-gradient bottom antireflective coating (BARC) film, which can be easily prepared by treating a silicon nitride film with oxygen plasma. The oxygen composition is gradually decreased inside the silicon nitride film. The optical constants of the silicon nitride film are also changed gradually. A reflectance of less than 1% for various highly reflective substrates with high thickness-controlled tolerance has been achieved. The optical-gradient film is also shown to have high thermal stability during the postexposure bake procedure. Results indicate that the optical-gradient-type BARC is suitable in both ArF and F2 excimer lasers for sub-70-nm lithography applications.
authors.affiliation: Department of Material Science and Engineering, National Taiwan University, Taipei, Taiwan. hlchen@ndl.gov.tw
authors.forename: Hsuen-Li
authors.initials: HL
authors.lastname: Chen
authors.forename: Wonder
authors.initials: W
authors.lastname: Fan
authors.forename: Tzyy-Jyann
authors.initials: TJ
authors.lastname: Wang
authors.forename: Fu-Hsiung
authors.initials: FH
authors.lastname: Ko
authors.forename: Run-Sheng
authors.initials: RS
authors.lastname: Zhai
authors.forename: Chien-Kui
authors.initials: CK
authors.lastname: Hsu
authors.forename: Tung-Jung
authors.initials: TJ
authors.lastname: Chuang