Modeling the inductively coupled plasma source and the comparison with experiments

Summary form only given. In recent years the inductively coupled plasma (ICP) source was widely used in sub-micron semiconductor manufacturing. To achieve uniform etching or deposition, it is required that the plasma uniformity at wafer surface to be better than 5% across the entire wafer surface. The plasma uniformity may vary with RF power, neutral gas pressure, chamber size and shape, coil design, etc. It is helpful to have a design tool that can predict the plasma characteristics under various operation conditions and design parameters. A fast and easy-to-use two-dimensional computer code was developed to model the ICP. The induction field is solved from the Maxwell equations by using a complex conductivity for the plasma. The ionization rate is related to the effective local induction electric field. With the charge neutrality assumption, the plasma transport is basically by ambipolar diffusion. The electron temperature can be estimated from a relation for the ionization rate and the electron temperature, or by adding an energy equation for electron. With suitable boundary conditions, the steady state plasma density distribution can be obtained by iterative calculations. The obtained plasma density distribution at various operating conditions will be compared with the results obtained by Langmuir probe measurements.