| Posted: June 17, 2008 |
IMEC reports progress on simplified high-k/metal gate process for the 32nm node |
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(Nanowerk News) At today's VLSI Symposium, IMEC reports
an improved performance for its planar CMOS using hafnium-based high-k
dielectrics and tantalum-based metal gates for the 32nm CMOS node. The
inverter delay advanced from 15ps to 10ps. IMEC also simplified its
high-k/metal gate process by decreasing the number of process steps from 15
to 9.
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High-performance (low-Vt) high-k/metal-gate CMOS has recently been achieved
by applying a thin dielectric cap between the gate dielectric and metal
gate. Both gate-first and gate-last integration schemes have proven to be
successful. While the gate-last scheme is now introduced in production for
high-performance products, the gate-first option remains attractive for
low-cost applications if its complexity can be reduced to the standard CMOS
process flow. One of the possibilities for gate first is a dual-metal
dual-dielectric process flow using mostly hard masks to pattern nMOS and
pMOS regions selectively.
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By applying conventional stress boosters to its gate-first dual-metal
dual-dielectric high-k/metal gate CMOS, IMEC increased the performance of
nMOS and pMOS transistors with 16% and 11% respectively. This results in an
inverter delay improved from 15ps to 10ps. For the first time, the
compatibility of conventional stress memorization techniques with
high-k/metal gate has been demonstrated.
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Also, IMEC has simplified the process complexity from dual-metal
dual-dielectric to single-metal dual-dielectric by using soft-mask
processes and wet removal chemistry. The process reduces the complexity by
40% or 6 steps compared to dual-metal dual-dielectric. It also allows
simpler gate-etch profile control and it offers better prospects for
scaling.
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And IMEC proved that the use of La and Dy capping layers do not show any
reliability issues.
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These results were obtained in collaboration with IMEC's sub-32nm CMOS
partners including Intel, Micron, Panasonic, Qimonda, Samsung, TSMC, NXP,
Elpida, Hynix, Powerchip, Infineon, TI, ST Microelectronics.
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About IMEC
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IMEC is a world-leading independent research center in nanoelectronics and
nanotechnology. Its research focuses on the next generations of chips and
systems, and on the enabling technologies for ambient intelligence. IMEC's
research bridges the gap between fundamental research at universities and
technology development in industry. Its unique balance of processing and
system know-how, intellectual property portfolio, state-of-the-art
infrastructure and its strong network of companies, universities and
research institutes worldwide position IMEC as a key partner for shaping
technologies for future systems. Further information on IMEC can be found at www.imec.be.
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