Over the last few years neural networks have been studied for potentia
l applications in plasma processing. The focus of this article will be
on two neural network models for complementary metal-oxide-semiconduc
tor production. The models were developed with strict statistical cros
s-validation and applied to developing a plasma gate etch controller a
nd a plasma model of a contact etch process. For a gate etch controlle
r, the process has been evaluated in a production environment and show
n to improve the process variance and throughput. For a model of a con
tact etch process we demonstrate that the model is limited by the inhe
rent noise in the training data and that the direct current bias and e
tch time are the key control factors that determine the product qualit
y at the end of the etch. (C) 1996 American Vacuum Society.