Patent ID: 6872262

Claim:
A method for wet processing of semiconductor wafers, comprising: providing at least one semiconductor wafer; providing a container for wet processing said at least one semiconductor wafer therein by providing a processing tank for positioning said at least one wafer therein, said processing tank being in a closed loop circulation processing stream, said closed loop circulation processing stream passing through said processing tank, said processing tank having at least one point-of-use wherein processing fluids sequentially flow past said at least one wafer, said processing tank being hydraulically full with processing fluids when said processing fluids flow past said at least one wafer; providing said processing fluids for wet processing said at least one semiconductor wafer by providing a means for supplying at least one fluid to said processing tank for removing contaminants from said at least one wafer, said means of supplying containing a first fluid flow control valve; first withdrawing said processing fluids from said processing tank by providing a means for first withdrawal of said processing fluids from said processing tank; second withdrawing said processing fluids from said processing tank by providing a means for second withdrawal of said processing fluids from said processing tank, said means of second withdrawal comprising a second fluid flow control valve; monitoring a volume of said processing fluids in said processing tank by providing a fluid overflow reference level for said processing tank; detecting said first withdrawing said processing fluids from said processing tank by providing a means for detecting said first withdrawal of said processing fluids from said processing tank, providing a first withdrawal signal; controlling said second withdrawing said processing fluids from said processing tank by providing a means for activating said means for second withdrawal of said processing fluids from said processing tank, said second withdrawing being controlled by said first withdrawal signal; and exposing said at least one wafer to said processing fluids, thereby wet processing said at least one wafer by: (i) positioning said at least one semiconductor wafer inside said processing tank; (ii) providing said processing fluids to said processing tank; (iii) activating said means for first withdrawal of said processing fluids from said processing tank; (iv) activating said means for second withdrawal of said processing fluids from said processing tank; (v) monitoring said volume of said processing fluids in said processing tank; (vi) monitoring said first withdrawing said processing fluids from said processing tank; and (vii) monitoring said second withdrawing said processing fluids from said processing tank.