Advanced process control of effective field height in a single wafer spin cleaning tool

The oxide loss behavior of buffered hydrofluoric (BHF) acid etch solution with elapsed time was investigated with and without advanced process control system (APC). The oxide loss amount increases with increasing the elapsed time in etching solution of BHF. The variation of BHF solution is considerable improved by at least to zero at run to run with APC. The result indicates this system is a promising solution method for well control in process window at mass production.