A high performance 0.12 /spl mu/m CMOS with manufacturable 0.18 /spl mu/m technology
High-performance 0.12 /spl mu/m CMOS devices with manufacturable 0.18 /spl mu/m technology are presented. A nominal I/sub dsat/N/P of 950/410 /spl mu/A//spl mu/m at an I/sub off/ of 12 nA//spl mu/m is achieved by reducing the body effect. The double-sidewall structure developed can reduce gate-fringe capacitance without increasing the junction leakage, and the inverter delay of 11 ps/stage is achieved at a nominal L/sub gate/ of 0.12 /spl mu/m. Small 6T-SRAM cells of 3.1 /spl mu/m/sup 2/ with 0.5 /spl mu/m gate pitch are implemented using a vertical well isolation and a self-aligned contact (SAC). In the SAC process, a blanket Si/sub 3/N/sub 4/ layer used as an etching stopper is optimized for the I/sub dsat/N/P ratio and the negative bias temperature instability (NBTI) reliability. The 9-level interconnection is optimized to reduce a long wire RC-delay.
Improvement of thermal stability of via resistance in dual damascene copper interconnection
Thermal stability of via resistance in the multilevel dual damascene Cu interconnection was investigated. The via resistance stability strongly depends on via size, via density and width of connecting Cu wires. The significant via-resistance shift was introduced by stress-induced voiding. To avoid the voiding failure, optimization of heat treatments after electroplating (EP)-Cu deposition are necessary for both stability of Cu films and adhesion of barrier layer with Cu. Thermal stress balance between Cu wires and inter-level-dielectric (ILD) is also important to suppress the via degradation. The dual damascene structure with lower-stress and lower-Young's modulus ILD films such as FSG can provide wider process windows for the stability of the via resistance.
Grain Boundary Diffusion of Copper in Tantalum Nitride Thin Films
This work investigates the temperature and composition dependencies of Cu diffusion in tantalum nitride (TaN x ) thin films. This study also measured the concentration profile of Cu using Auger electron spectroscopy. Also investigated herein are the morphology and the crystalline microstructure of tantalum nitride films using atomic force microscopy, scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, and X-ray diffraction, respectively. Lattice and grain boundary diffusivities were extracted from the concentration profile using the Whipple analysis of grain boundary diffusion, after annealing samples at temperatures between 500 and 800°C. Analysis results indicated that the Whipple model correlates well with experimental results.