The feasibility of low-ohmic FIB contacts to silicon with a localized silicidation was presented at ISTFA 2004 [1]. We have systematically explored options in contacting diffusions with FIB metal depositions directly. A demonstration of a 200nm x 200nm contact on source/drain diffusion level is given. The remaining article focuses on the properties of FIB deposited contacts on differently doped n-type Silicon. After the ion beam assisted platinum deposition a silicide was formed using a forming current in two configurations. The electrical properties of the contacts are compared to furnace anneal standards. Parameters of Schottky-barriers and thermal effects of the formation current are studied with numerical simulation. TEM images and material analysis of the low ohmic contacts show a Pt-silicide formed on a silicon surface with no visible defects. The findings indicate which process parameters need a more detailed investigation in order to establish values for a practical process.

Process options of FIB circuit edit accessing active area in silicon through chip backside are presented. The full process is divided in modules. The technological readiness of the different modules is discussed. New results for the two most critical modules, endpoint detection of the global FIB trench in silicon, and contact resistivity of FIB deposited metal interconnect on diffusion, are presented. Investigated endpoint detection processes are FIB image contrast of the wells and of STI (shallow trench isolation). The contact to diffusion is in the range of 2-5 x 10-7 Ωcm2 on highly doped n-Si, about 10x higher on highly doped p-Si, with linear I-V characteristic.