Bi-layer silylation process using anti-reflective-coatings (ARC) for making distortion-free submicrometer photoresist patterns

摘要

A novel bi-layer using a silylation process and anti-reflective coatings are employed for making distortion-free submicrometer photoresist patterns. The method involves forming a multilayer composed of a bottom anti-reflective coating (BARC), a first photoresist layer, a middle anti-reflective coating (MARC), and a silylated second photoresist layer for patterning an underlying electrically conducting layer, such as for FET gate electrodes. The upper photoresist layer is then optically exposed through a mask to form a latent image, and is silylated selectively to form a silicon rich region. The BARC and MARC layers prevent reflected radiation from the underlying structure during the optical exposure, thereby providing a distortion-free latent image. The selective silylation of the latent image portion of the photoresist serves as an excellent etch mask for oxygen plasma etching which is then used to pattern the remaining photoresist layer and anti-reflective coatings. The resulting distortion-free photoresist pattern is then used as an etch mask for etching the underlying electrically conducting layer.