Method for analyzing manufacturing data

A method of manufacturing, e.g., integrated circuits, and of managing a manufacturing process. Product unit (circuit) variation data is collected from clustered product units (wafer sites). Collected data is grouped according to a selected manufacturing parameter. Each group is normalized for the selected manufacturing parameter. Normalized groups are combined. Normalized process data is checked for variances and the data is regrouped and renormalized until variances are no longer found. Each identified variance is correlated with a likely source. Then, each said likely source is addressed, e.g., a tool is adjusted or replaced, to minimize variances.