Database Development of SiO Etching with Fluorocarbon Plasmas Diluted with Various Noble Gases of Ar, Kr, and Xe.

In the semiconductor industry, fluorocarbon (FC) plasma is widely used in SiO etching, with Ar typically employed in the dilution of the FC plasma due to its cost effectiveness and accessibility. While it has been reported that plasmas with other noble gases, namely Kr and Xe, have distinct physical properties such as electron density and temperature, their implementation into plasma etching has not been sufficiently studied. In this work, we conducted SiO etching with FC plasmas diluted with different noble gases, i.e., FC precursors of CF and CHF with Ar, Kr, or Xe, under various gas flow rates of each as well as plasma diagnostics for the process interpretation. We show that Ar, Kr, and Xe gas mixtures depend on the FC precursor flow rate and the pattern width in a significantly different manner and we elucidate these findings based on plasma diagnostic results. The results of this work are expected to offer a practical etching database for diverse applications including plasma process engineering and the development of plasma simulation in the semiconductor industry.