METHOD FOR PLASMA-CHEMICAL ETCHING OF SILICON STRUCTURES Russian patent published in 2024 - IPC H01L21/30 

FIELD: solid-state electrical appliances.

SUBSTANCE: invention can be used for production of integrated circuits, micromechanical devices – microelectromechanical systems (MEMS) and microfluidics based on silicon. Essence of the invention consists in the fact that the method for plasma-chemical etching of silicon structures includes stages of silicon etching, deposition of a passivating film, sputtering by ion bombardment of a passivating film from the bottom of the structure, wherein the ratio of the durations of the etching and deposition stages is not more than 3 with a sequence of stages: first, a silicon etching stage is carried out for 1-9 s in SF6 gas with addition of 5-7% oxygen, then a stage of deposition of a fluorocarbon film from octafluorocyclobutane for 1-3 s, after a stage of sputtering by ion bombardment of a passivating film from the bottom of the structure in a mixture of argon and SF6 gas for 0.5-1 s at a fixed value of power of the high-frequency plasma source at all stages in range of 700-800 W, while maintaining the temperature of the substrate holder with a plate in range of 15-20 °C.

EFFECT: enabling formation of silicon structures with ultra-low aspect ratio with minimum surface roughness and profile anisotropy.

1 cl, 3 dwg