1. A method comprising: constructing an advanced process control (APC) model table comprising APC model parameters of a plurality of products and a plurality of work stations, with the plurality of products and the plurality of work stations as rows and columns of the APC model table, wherein the APC model table comprises empty cells and cells filled with existing APC model parameters; calculating average APC model parameters of the existing APC model parameters; filling the empty cells with the average APC model parameters as initial values; evaluating a weighting for each of the plurality of products, wherein the weighting is between 0 and 1; performing an iterative calculation using the weighting to update the empty cells with updated values; and using one of the updated values to control one of the plurality of work stations to process a wafer of one of the plurality of products, with the one of the updated values being corresponding to the one of the plurality of work stations and the one of the plurality of products in the APC model table.