METHOD OF ANISOTROPIC PLASMA ETCHING OF SILICON MICROSTRUCTURES IN A CYCLIC TWO-STEP OXIDATION-ETCHING PROCESS Russian patent published in 2019 - IPC H01L21/3065 

FIELD: electromechanics; micromechanics.

SUBSTANCE: invention relates to the technology of making transistors, integrated circuits, power electronics devices and silicon-based micromechanic devices (MEMS). Method of anisotropic plasma etching of silicon is a cyclic two-step process of etching-passivation, characterized in that at passivation step as passivating film on surfaces of formed microstructure layer SiO₂ is used, created by reaction of silicon oxidation in plasma O₂. In order to prevent change in the composition of the passivating film and for better separation in time of the steps of etching and passivation, as well as prevention of formation of a mixture of SF₆ and O₂, in which effective surface passivation does not take place with silicon oxide layer, pumping steps are used between etching and passivation steps of 0.5 to 10 s. Advantage of this method is absence of necessity of cooling and thermal stabilization of plate in process chamber at cryogenic temperatures, as well as the absence of contamination of the formed microstructure with fluorine-polymer films, which eliminates the need to use additional process operations for cleaning the formed silicon microstructures from contamination with polymers.

EFFECT: technical result is providing anisotropic etching of silicon at temperature close to room temperature.

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