Scrubber clean induced device IDDQ fail

IDDQ is an effective test method to screen out process related defects during chip probe (CP) test. Through failure analysis it was determined that some production wafers suffering minor yield loss in wafer edge for IDDQ failure was the result from inter layer dielectric cracks. Monitor wafers were processed and utilized for root cause finding using layer-by-layer inline KLA scan review, where the problem was found to be a scrubber clean tool used during a TiN glue layer post CVD clean stage. This caused the wafers to be impacted by process induced ESD damage. The scrubber clean stage is extensively used in the manufacture process to remove particles from the surface of wafer. The possible source of the ESD damage during scrubber clean was studied. After improving the scrubber clean process, the wafer edge yield loss with IDDQ failure was recovered.