US Patent 7382451 Method of defect inspection

A plurality of cassettes, each having a plurality of wafers respectively having a first defect information, is selected. Each of the cassettes is then assigned to a corresponding tool having at least one reaction chamber, and the wafers are substantially equally assigned to the reaction chambers. A first process is then performed on each of the wafers in the reaction chamber. Finally, a first defect inspection process is performed on each of the wafers.