Image Reversal Trilayer Process Using Standard Positive Photoresist

摘要

Conventional trilayer schemes alleviate the decreasing photoresist budgets as well as satisfy the antireflection issuesassociated with high NA imaging. However, a number of challenges still exist with standard trilayer processing, mostnotable among which is the lack of broad resist compatibility and trade-offs associated with improving Si content, suchas stability and lithography performance. One way to circumvent these issues is to use a silicon hard mask coated over aphotoresist image of reverse tone to the desired pattern. Feasibility of this image reversal trilayer process wasdemonstrated by patterning of trenches and contact holes in a carbon hard mask from line and pillar photoresist images,respectively. This paper describes the lithography, pattern transfer process and materials developed for the imagereversal trilayer processing.