PLASMA ASH AND WET CLEAN IMPACT TO POROUS LOW-K FOR MULTILEVEL CU/LOW-K INTERCONNECTS

摘要

Various ash plasmas and clean chemistries have been screened for compatibility with organo-silica-glass (OSG) porous low-k films (k-values of 2.2) for Cu/Low-k interconnect. Fourier Transform Infrared (FTIR) spectroscopy and k value measurement have been utilized to characterize the bulk film properties. Ash chemistries and plasma bias can reduce the film thickness, suppress SiC-bonding and weaken the film's resistance to wet clean chemistry damage. The damage to porous low-k can distort the trench profiles and induce high metal line leakage. By improving the ash and clean process, we demonstrated porous low-k/Cu interconnects with good profile and low leakage.