Key Effects and Process Parameters Extraction on the CD of Reactive Ion Etching (RIE) Based on DOE Modeling

The critical dimension (CD) is highly influenced by the reactive ion etching (RIE) of silicon in the CMOS technology. The CD has to be well-controlled since it is one of the most important features related to process stability and product quality. However, the RIE process involves a lot of parameters which are highly confounded and entangled and thus it is very difficult to analyze the process. To study and extract the influences of these parameters in terms of CD variation, screening experiments are carried out to obtain the necessary factors to develop a CD-related model. An elaborated model, based on the selected parameters, is then built up via applying the design of experiments and response surface optimization. This model is validated to be capable of characterizing the process as well as predicting the CD.