Abstract
As logic technologies ramp to 0.13 µm and beyond, integrating lower resistance dual damascene copper plated BEOL interconnects with low k (k = 2.65) processing with Dow Chemical’s SiLKTM dielectric and with silicon-on- insulator (SOI) technology offers even higher performance (> 1GHz) RISC microprocessor operation [1,2]. Such low k dielectric films dramatically reduce the line-to-line capacitance over conventional silicon dioxide dielectric films as well as FSG (fluorinated silicon glass) dielectric films. Electrical characterization of submicron copper interconnects with SiLKTM offer challenges not present with SiO2 or with FSG dielectric films. Similarly, deprocessing such low-k dielectric films require approaches very different than for silicon dioxide dielectric films or even FSG films. Conventional tungsten contact probe techniques and even FIB deposited pads for submicron probing present concerns as applied to low-k dielectric films. Alternative techniques in electrical probing employing atomic force microscopy (AFM) surface imaging may provide a solution. This technique combines the capability to precisely position multiple probe tips within a small footprint and to perform electrical measurements on features as small as 0.10 µm. The low total input capacitance loading with this technique is applicable to AC waveform characterization for higher speed RISC microprocessor designs.
