Novel approach to surface imaging

In the past, a number of authors have described the advantages of the silylation reaction performed in a novolak resist's latent image. Both the advantages and difficulties were described. A process based on silylation of latent images was shown to improve the working resolution in a novolak resist due to the surface imaging principle. The difficulties included swelling of the resist film during silylation resulting in some loss of dimensional control of critical dimensions. This paper describes a different approach to near surface imaging. The method relies on the use of spin-on, closely planarizing polymeric antireflective coating, such as AZ®BARLi® coating, followed by imaging thin (less than 0.5 micron) i-line resist. After a conventional lithographic process which includes a wet develop step, a silylation reaction is performed. Swelling of the real resist image due to silylation is controllable within necessary tolerances. Image transfer process of the silylated image is also described. ©2003 Copyright SPIE - The International Society for Optical Engineering.