Plasma etching process plays a critical role in semiconductor manufacturing. Because
physical and chemical mechanisms involved in plasma etching are extremely complicated,
models supporting process control are difficult to construct. This paper uses a 35-run
D-optimal design to efficiently collect data under well planned conditions for important
controllable variables such as power, pressure, electrode gap and gas flows of
Cl2 and He and
the response, etching rate, for building an empirical underlying model. Since the
relationship between the control and response variables could be highly nonlinear, a
generalized regression neural network is used to select important model variables and
their combination effects and to fit the model. Compared with the response surface
methodology, the proposed method has better prediction performance in training and testing
samples. A success application of the model to control the plasma etching process
demonstrates the effectiveness of the methods.