Antireflection coatings for use in photolithography.

摘要

Reflection of incident optical radiation (18) from a highly reflective metal layer (12), such as aluminum or titanium, into a photoresist layer (14) is reduced by interposing a layer of titanium nitride (16) between the metal and photoresist layers. The thickness of the TiN layer depends on the wavelength of the optical radiation used to expose the photoresist and on the optical properties of the underlying metal layer. Reflectance of less than about 2% may be achieved using the TiN layer in conjunction with aluminum and less than about 5% in conjunction with titanium, in accordance with the invention. If left in place after patterning an underlying aluminum layer, the TiN layer also serves to suppress hillock formation in the aluminum layer.