Progress Towards Production Worthy Developable BARCs (DBARCs)

摘要

Developable bottom anti-reflective coating (DBARC) technology holds promise in two main areas of lithography. The first application of DBARC is in implant lithography where patterning implant levels would greatly benefit from improved reflection control such as provided by a conventional BARC. However, implant layers cannot withstand BARC open etch thereby making DBARC an attractive solution as the resist and DBARC are simultaneously dissolved during the development step leaving the underlying substrate ready for implantation. In comparison to current implant processes with top anti-reflective coatings (TARC), DBARCs are anticipated to offer improvements in reflection control which would translate to improved CDU and increased process window for both KrF and ArF implants. Indeed, this area has long been considered the ideal insertion point for DBARC technology. The second area where DBARC technology can make a significant impact is in non-implant lithography. In this large segment, the ability to replace a conventional BARC with a DBARC affords the device maker the ability to simplify both lithographic and integration processes. By replacing the BARC with a DBARC, the BARC open etch is negated. Furthermore, by applying this strategy on multilayer stacks it is possible to greatly simplify the process by avoiding both CVD steps and pattern transfer steps thereby easing integration. In this area, DBARC technology could have merit for low k_1 KrF and ArF (dry) lithography as well as in immersion ArF processes. This paper describes our results in designing production worthy DBARCs for both implant and non-implant applications. A newly developed KrF DBARC platform is evaluated for logic implant applications and compared to a standard TARC implant process. Post develop residue and detectivity are checked for the new platform and the results compared to production worthy BARC and implant resists. A new ArF platform was also developed and initial lithographic results are reported for an implant application. Several non-implant applications were also investigated and results are reported for high resolution KrF and ArF (dry) lithography as well as an immersion ArF process.