Toshiba Corp. has announced a cost-effective 32nm CMOS platform technology that offers higher density and improved performance while halving the cost per function from 45nm technology.
Advanced semiconductor process migration faces challenges to achieve both cost competitiveness and enhanced performance for stricter design rules. This requires innovative technological optimization in lithography and patterning integration, materials, and device design.
Realizing the strict design rule in the 32nm generation was originally seen as requiring dual exposure technology in the lithography process, which would result in higher process costs due to increased process steps, and in degraded manufacturing yields owing to increased process dusts. Toshiba realized an architecture based on single exposure lithography by applying ArF immersion lithography with a NA 1.3 and over, and by optimizing the lithography illumination conditions.
The platform was achieved by application of advanced single exposure lithography and gate-first metal gate/high-K process technology. This technology enables a 0.124μm² SRAM cell and a gate density of 3,650 gate/mm². This SRAM cell is the smallest yet achieved in the 32nm generation. The platform technology is based on a 32nm process technology developed jointly with NEC Electronics Corp.
The development work also demonstrated that application of a metal gate/high-K not only boosts transistor performance but also reduces threshold voltage mismatch, which affects stable operation of SRAM and logic circuits. In addition, a bent-shaped type cell was selected for layout optimization, which also contributed to reduce threshold voltage mismatch.
By adopting this approach, Toshiba realized a 32nm CMOS platform design that reduces cost per function by 50% from 45nm technology, an achievement that would have been impossible with conventional poly/SiON and double patterning.