A generalized plasma etching model with an oblique magnetic field

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Abstract
A generalized plasma etching model with an oblique magnetic field has been developed. The new model is a continuation of our previous models presented in recent papers [E. Zawaideh and N. S. Kim, J. Appl. Phys. 6 2, 2498 (1987); 6 4, 4199 (1988)]. New generalized plasma transport equations that are valid in the limit of large drifts (e.g., E×B drift, where E and B are the electric and magnetic field vectors, respectively) are introduced. These new generalized plasma transport equations are also valid for collisional [λ/L≪1] to weakly collisional plasmas [λ/L∼0(1)], where λ is the ion mean free path and L is the smallest of the scale lengths of the electric field or the gradient in the macroscopic plasma parameters. The new plasma transport equations coupled with both Poisson’s equation and our previous generalized etching equations are used to model the magnetron plasma etching processes. As an example, silicon (Si) plasma etching with a mixture of helium (He) and chlorine (Cl2) gases is applicable to illustrate this new generalized model. The model has shown a definite trend toward agreement with the experimental etch rates of Si for various plasma and reactor parameters (e.g., neutral gas pressure and rf power).