A novel UV baking process to improve DUV photoresist hardness

A new baking gas using a mixture of NH/sub 3/ and N/sub 2/ gases can effectively reduce the photoresist thickness shrinkage, CD variation and footing during the UV-bake DUV photoresist hardening process has been developed. After this UV baking process, a higher etch selectivity to photoresist and better CD control and profile processing can be achieved in high density plasma (HDP) dry etchers for applications to 0.2 /spl mu/m contact holes with aspect-ratio greater than 5 and 0.22 /spl mu/m aluminum metal lines with aspect-ratio of 2.5.