IMEC presents functional CMOS SRAM cells

The 0.099um SRAM cells are made with FinFETs and have both the contact and metal1 layer printed using ASML's full field extreme ultraviolet (EUV) Alpha Demo Tool (ADT).

The ultra-small circuit structures were made using Applied Material's most advanced deposition systems.

These results were presented during IMEC's core partner review week, which was attended by 250 experts representing IMEC's industrial partners in its CMOS scaling programme.

The density of the new cells is 0.099um, representing a 47 per cent area scaling compared to the 0.186um of IMEC's 32nm cell reported last year.

For the front-end-of-line process, IMEC used its high-k/metal-gate FinFET platform.

The FinFETs consist of HfO2 as dielectric and TiN as metal gate and NiPt silicide for the source/drain.

The minimum active FIN pitch is 90nm.

The FinFET layers were printed using ASML's 1900i immersion lithography tools.

The metallisation of the contact holes was realised using Applied Materials advanced contact processing modules for inter-layer barrier Ti and TiN before tungsten fill and chemical mechanical polishing.

Compared to the 32nm cell, where only the contact holes were printed with the EUV tool, IMEC used ASML's ADT to pattern both the contact with a size of approximately 45nm and metal1 layers (60nm width and 46nm spaces).

The results showed a good overlay performance.

And the single patterning approach further strengthens the case for EUV as a cost-effective solution.

In its core programme, IMEC works together with leading IC companies on future CMOS technologies.

Key partners in 2009 are Intel, Micron, Panasonic, Samsung, TSMC, Elpida, Hynix, Powerchip, Infineon, NXP, Qualcomm, Sony and ST Microelectronics.