Modeling of plasma processing reactors: review and perspective

Low temperature plasmas (LTPs) are widely used in the semiconductor industry to etch, deposit, modify, and pattern thin films during the fabrication of integrated circuits. Modeling techniques used to simulate industrial processing plasmas are reviewed in this article. The authors also provide their perspective on areas of highest research and development need. The most common plasma sources used in the semiconductor industry are capacitively coupled plasmas, inductively coupled plasmas, magnetrons, magnetized and unmagnetized microwave plasmas, and remote plasmas. These LTP systems can be simulated using global, fluid, and particle-based kinetic modeling techniques. A variety of hybrid methods have also been developed that supplement fluid plasma models with kinetic models for aspects of the plasma behavior. The industry expects plasma models to be quantitatively accurate, so they can be used as an LTP system design tool. The optimal models are usually a thoughtful blend of precise physics and experimentally guided refinements. The authors highlight the benefit and need of multi-faceted plasma model validation studies in which plasma sources are first characterized using a variety of complementary diagnostics. Quantitatively accurate models for these plasmas are then developed to test the accuracy of key aspects of the plasma including the electron energy distribution function, ion energy distribution function at surfaces, charged and neutral species densities or fluxes, and gas temperature. An important aspect of the validation exercise is the development of the plasma chemistry mechanisms and models for plasma–surface interaction.