For oxide-CMP process in semiconductor manufacturing, which requires high precision, Run-to-Run control has been developed. The Run-to-Run control is a kind of repetitive control to adjust polishing time at every start of work in a work sequence. This control is based on a process model, which expresses the relation between polishing time and polished thickness. In this report, a modeling method of nonlinear process models is described for oxide-CMP with ceria slurry. In this method, model candidates are generated by combining arbitrary terms, whose order is up to three. And one model, which satisfies the conditions related to polishing process, is selected. The model accuracy and precision in polished thickness is evaluated with actual manufacturing samples. As the result, for 9 LSI products from 18 products, models satisfying control limits of film-thickness after CMP are automatically obtained.
