We evaluated the rate limiting steps in a post sulfuric acid/hydrogen
peroxide mix dump rinsing process. The parameters we examined include, the
pull-out velocity from the chemical bath, the draining during transport into
the rinse tank, immersion into the rinse tank, dumping, draining after a
dump cycle and flow rate during fills between dumps. Based on our
investigations an optimized dump rinsing process was developed using
programmed flow rates and dumping cycles. The quality of the optimized
rinsing process was determined by measuring sulfur residue and light point
defects on wafer surfaces that had undergone the optimized rinsing process.
This optimized process requires 5 minutes and 75 liters of water, replacing
a process that initially ran for up to 16 minutes and consumed 600 liters of
water. Our optimized rinsing process, resulted in a factor of five saving in
water consumption and two in cycle lifetime with no statistical degradation
in surface quality.