(Invited) Enabling 5nm and Beyond Device Fabrication with New Etch Technologies

Abstract

All logic device roadmaps predict significant change in the form and nature of logic at 5 nm. III-V’s, SiGe, Ge, nanowires and nano-sheets, while attractive as device options, bring pause to process and integration teams that need to integrate new materials or new material forms. Research grade devices are certainly possible today but high volume manufacturing of new devices in whatever form they may take requires change to unit processes available in today’s fabrication facilities. The question is whether something entirely new is needed or it is a matter of enhancing the capabilities of process and equipment that exists today. A key of those responsible for next generation logic is damage in one form or another by the (plasma) etch unit process. III-V’s, SiGe and Ge devices are particularly sensitive to damage. This has motivated calls for a complete move to thermal etch processes potentially upending available integration approaches. Unfortunately, thermal processes are themselves not damage free in that it is impossible not to leave interfaces and the immediate sub-surfaces unaltered. Fortunately, advances in plasma etch technology allow plasma etch to meet and exceed thermal process performance. Pulsing technology went a long way to mitigating damage caused during silicon device fabrication more than a decade ago. Now, advanced pulse technology applied to advanced plasma sources delivers performance equivalent to thermal processes by precise control of surface passivation, surface volatilization and surface reaction by-products. Concurrent advances in applying novel process chemistries (plasma based self-limited material removal and deposition processes) are also ready for new logic materials. Key is the availability of advanced materials chemistry simulations for use in process development. The research opportunities for new etch technology for “selective area etching” in advanced logic manufacturing will be the next frontier of R&D activities.