Breaking new ground; from current progress to future innovations in HARC etching technology

Abstract As the integration density of DRAM and 3D NAND continues to increase, the demand for high aspect ratio contact (HARC) etching technology is growing. Although considerable progress has been made, HARC technology still faces critical challenges, such as non-uniform plasma, pattern deformation, and depth loading caused by limitations in the transport of ions and radicals to the bottom of deep holes. To overcome these challenges, innovative technologies, including non-sinusoidal waveform bias power and cryogenic etching with alternative etchants, have been introduced. In particular, cryogenic etching is less sensitive to bias power and can help reduce emissions of high global warming potential gases. However, the increased complexity of the recipes requires a considerable number of wafers and trial runs to achieve the desired profiles. Consequently, collaboration with AI driven tools has drawn great interest. This paper summarizes recent technical advances in HARC etching and outlines the technical requirements for future progress.