Traditional silicon integration concepts are based on a few materials like silicon, silicon oxide and silicon nitride. Using only these materials limits the integration options. Resists - also used in conventional semiconductor processes - could be a fourth alternative, but are limited since processing at higher temperatures is not possible.
Infineon co-developed a new thermally stable organic polymer combining the advantages of both worlds and demonstrated the feasibility of this organic material for a DRAM trench integration scheme. In this approach, a modified version of an organic spin-on-polymer is used with ideal gap fill properties, good planarization and temperature stability beyond 450°C. Test samples of 256M DDR DRAM chips fabricated on 140 nm ground rules show high yields. This concept demonstrates the feasibility of FEOL (Front-End Of Line) integration schemes utilizing the newly developed material. Furthermore the demonstrated integration scheme is capable of extending DRAM trenches to generations below 70nm.