BEOL Metal and Dielectric Films
As transistor technologies continue to scale down from 2X to 1X nodes, pitch scaling is getting more complex throughout the FEOL, MOL and BEOL. Various patterning schemes and pitch splitting techniques are being used by device manufacturers to extend 193nm immersion lithography to enable 3D FinFET / Trigate devices. BEOL scaling of damascene copper is also facing challenges with integration of porous ULK materials and the issue of increased resistivity emanating from grain boundary and surface scattering.
Double, triple and quadruple patterning options are being used or considered with metal hard mask. While a lot of new materials are being explored for logic and NAND devices, TiN is currently used in production due to its high selectivity to ULK. Hard mask materials deposited have to be zero stress and prevent buckling of low strength ULK materials.
Tango has developed the process capability to modulate stress close to zero for Hard mask layers. Stochiometry and density of the films are extremely uniform over the wafer for control over etch-selectivity.
Tango has developed the process on the Axcela platform for wafers from 150mm to 330mm.
Click here for more information on Axcela.