Methods and Challenges to extend existing dry 193nm medium NA lithography beyond 90nm

摘要

In order to fulfill the demands of further shrinkage of our mature 90nm logic litho technologies under the constraints of costs and available toolsets in a 200mm fab environment, a project called "Push to the Limits" was started. The aim is to extend the lifetime and capabilities of existing dry 193nm litho toolsets with medium to low numerical aperture, coupled with the availability of materials and processes which were known to help up CD miniaturization and to shrink the 90nm logic litho process as far as possible. To achieve this, various options were explored and evaluated, e.g. optimization of illumination conditions, evaluation of new materials, usage of advanced RET techniques (OPC, LfD, DfM and ILT) and resolution enhancement by chemical shrink (RELACS~?). In this project we demonstrate how we were able to extend our existing 90nm technology capability, down close to 65nm node litho requirements on most critical layers. We present overall result in most critical layer generally and specifically on most difficult layer of contact. Typical contact litho target at 100nm region was enabled, while realization of 90nm ADI target is possible with addition of new process materials.