METHOD FOR ANISOTROPIC PLASMA ETCHING OF SILICON MICROSTRUCTURES IN NITRIDIZATION AND ETCHING CYCLIC PROCESS Russian patent published in 2023 - IPC H01L21/3065 

FIELD: silicon device manufacturing.

SUBSTANCE: invention is related to manufacturing integrated circuits, power electronics devices and micromechanical devices (MEMS) based on silicon. The method for anisotropic plasma etching of silicon includes a cyclic two-step etching process consisting of alternating steps of anisotropic plasma-chemical etching and passivation, in which silicon is etched in SF₆ plasma at the etching step, and a passivating film is created on the surfaces of the formed microstructure at the passivation step, during the passivation step, either a layer of SiN_x created by the reaction of silicon nitridation in N₂ plasma, or a layer of SiO_xN_y created by the reaction of silicon nitridation in the plasma of an O₂/N₂ mixture with a nitrogen percentage in the range of 10-100% are applied as a passivating film on the exposed silicon surfaces.

EFFECT: invention enables anisotropic etching of silicon at a temperature close to room temperature, since there is no need for deep cooling and thermal stabilization of the wafer in the process chamber at cryogenic temperatures.

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