Advanced sub 0.13µm Cu Devices – Failure Analysis and Circuit Edit With Improved FIB Chemical Processes and Beam Characteristics
Abstract Advances in FIB (focused ion beam) chemical processes and in the Ga (gallium) beam profile are discussed; these advances are necessary for the successful failure analysis, circuit edit and design verification of advanced, sub-0.13µm Cu devices. Included in this article are: a novel FIB method (CopperRx) for smoothly milling thick, large grained Cu lines; H2O and O2 processes for cleanly cutting thin, smaller grained Cu lines, thereby forming electrically open interconnects; a XeF2 GAE (gas assisted etching) process for etching low k, CVD dielectrics such as F and C doped SiO2; H2O and XeF2 GAE processes for etching low k, spin-on, organic dielectrics such as SiLK; a recently developed recipe for the deposition of SiO2 based material with intermediate resistivity (106 µohm·cm) which is useful in the design verification of frequency sensitive, high speed analog and SOC (system on chip) circuits; an improved, more Gaussian Ga beam with less current density in the beam tails (VisION column) which provides higher resolution, real time images needed for end-point detection on sub 0.13µm features during milling.