Patent ID: 6174644
Filing Date: 2001-01-16
Classification: G03F,H01L,Y10S

Abstract:
An anti-reflective coating made by the process of providing:a source of light having a first wavelength;an integrated circuit substrate;a pad oxide layer formed on said integrated circuit substrate;a first silicon nitride layer having a first thickness and a first index of refraction formed on said pad oxide layer wherein said first silicon nitride layer is formed so that said first index of refraction is between about 2.08 and 2.12;a second silicon nitride layer having a second thickness and a second index of refraction formed on said first silicon nitride layer wherein said second silicon nitride layer is formed so that said second index of refraction is between about 1.88 and 1.92 and said second thickness is about equal to one fourth of said first wavelength divided by said second index of refraction;a photoresist layer formed on said second silicon nitride layer wherein said photoresist layer has an index of refraction of between about 1.66 and 1.70 and said photoresist layer will be exposed using said source of light having said first wavelength.