Optical-gradient antireflective coatings for 157-nm optical lithography applications.
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.
Chen
Hsuen-Li
HL
Department of Material Science and Engineering, National Taiwan University, Taipei, Taiwan. hlchen@ndl.gov.tw
Fan
Wonder
W
Wang
Tzyy-Jyann
TJ
Ko
Fu-Hsiung
FH
Zhai
Run-Sheng
RS
Hsu
Chien-Kui
CK
Chuang
Tung-Jung
TJ