Pitch doubling technologies are necessary for the 32nm half-pitch (HP) and beyond in order to extend optical
lithography. Many different techniques have been examined including Litho-Litho-Etch (LLE), Litho-Etch, Litho-Etch
(LELE), and Sidewall Image Transfer (SIT). Keeping all of the processes inside the litho cluster, as LLE achieves,
affords process simplification and potential for the lowest cost of ownership for pitch doubling. Within LLE alone, there
are varying approaches including spin-on chemical freeze materials, thermal cure, UV curable materials, among others.
The challenge is to provide robust process performance while still achieving the lowest cost of ownership.
For this paper, we are concentrating on the evaluation of the UV cure process. Our findings are the results of
optimization of the UV cure dose and bake conditions and its affect on the lithographic performance. The optimized
process was investigated for defectivity, critical dimension (CD), repeatability, pattern distortion, etch performance and
readiness for high volume manufacturing. With respect to CD, the investigation included absolute value change (shrinkage or growth) and CD uniformity (CDU). For pattern distortion, we investigated line shrinkage, corner rounding, and line end pull back. Defectivity checks were conducted for full wafer comparison pre and post the UV cure process. Manufacturability measures include throughput, cost of ownership and process stability.