Patent Number: 6,297,521

Title: Graded anti-reflective coating for IC lithography

Abstract: A substantially continuously graded composition silicon oxycarbide (SiOC)antireflective coating (ARC) or antireflective layer (ARL) is interposedbetween a photoresist layer and an underlying substrate. The ARC matchesan optical impedance at the interface between the ARC and photoresist. Theoptical impedance decreases (absorptivity increases) substantiallycontinuously, in the ARC in a direction away from the interface betweenthe ARC and the photoresist. The ARC composition is graded from SiOC, atits interface with the photoresist, to SiC or Si, in a direction away fromthe photoresist. Reflections at the ARC-photoresist interface aresubstantially eliminated. Substantially all incident light, includingultraviolet (UV) and deep ultraviolet (DUV) light, is absorbed in the ARC.As a result, substantially no light reaches or is reflected from theunderlying substrate. Photolithographic limitations such as swing effectand reflective notching are reduced.

Inventors: Forbes; Leonard (Corvallis, OR), Ahn; Kie Y. (Chappaqua, NY)


International Classification:

Expiration Date: 10/02/2013