Highly Reliable Thin MIM Capacitor on Metal (CoM) Structure with Vertical Scalability for Analog/RF Applications

Highly reliable thin MIM capacitor on metal (CoM) structure has been developed to be fitted in scaled-down Cu BEOLs without any change in the interconnect structure. The 100 nm-thin CoM structure, covering the opened area in the barrier dielectric (SiCN-cap) on the Cu interconnects, guarantees vertical scalability in the shrinking interconnect layers. High reliability of 10-year TDDB lifetime is achieved for thin SiN with 6.3 fF/mum² by the rounded shoulder and the flattened bottom surface of the cap-opening, which is accomplished by novel physical-bombardment enhanced plasma-etching. The low parasitic resistance of the bottom electrode, supported by the Cu line, leads to fast response in GHz range, suitable for cost-effective digital consumer chip with RF/mixed-signal functions.