Numerical simulation of plasma-chemical etching reactors

The effect of nonisothermality of the operating continuum on the etching rate and uniformity in a planar plasma-chemical reactor was analyzed. The temperature of an electrode with a wafer was assumed specified and varied in a range which is characteristic for such reactors. Convection, molecular conduction and radiation were taken into account. The calculations were carried out for etching of silicon in tetrafluoromethane plasma within the operating regimes of industrial reactors. It was shown that thermodiffusion gives up to 20% of full flow of active species on the wafer and can affect the etching uniformity if radial temperature gradients are present. The radiation substantially influences the gas temperature distribution. Convective heat and mass transfer on the wafer surface are negligible. If the temperatures of wafer and surrounding electrode are constant then the received temperature nonuniformity of the operating medium does not worsen the etching uniformity.