Deep silicon etching method

Abstract

The invention discloses a deep silicon etching method. The deep silicon etching method comprises steps that: a deposition step, a protection layer is generated to protect an etching side wall; an etching step, an etching bottom portion and the etching side wall are etched; the deposition step and the etching step are repeated till the whole deep silicon etching process is over; a bottom portion smoothing step is further included, wherein the bottom portion smoothing step comprises that a fluorine-containing gas is utilized to carry out plasma processing to remove polymers generated because of deposition at the etching bottom portion, the technology pressure employed in the bottom portion smoothing step is smaller than the technology pressure employed in the etching step, at least one bottom portion smoothing step is carried out in the whole deep silicon etching process. Through the deep silicon etching method, gradual increase of the etching bottom polymer is inhibited in the deep silicon etching process, generation of a micro mask layer or silicon grasses is inhibited, and thereby the etching rate of deep silicon etching and the selectivity ratio are improved, and roughness of the etching bottom is ameliorated.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a deep silicon etching method. Background technique [0002] With MEMS (Micro-Electro-Mechanical Systems, Micro-Electro-Mechanical Systems) devices and MEMS systems being more and more widely used in the automotive and consumer electronics fields, and TSV through hole etching (Through Silicon Etch) technology in the future packaging field With broad prospects, the dry plasma deep silicon etching process has gradually become one of the mainstream processes in the field of MEMS processing and TSV technology. [0003] The main difference between the deep silicon etching process and the general silicon etching process is that the etching depth of the deep silicon etching process is much larger than that of the general silicon etching process, and the etching depth of the deep silicon etching process is generally tens of microns Even hundreds of microns, while the etching d...

AI Technical Summary

Problems solved by technology

Micromask or silicon grass generation can lead to poor roughness of the bottom of the etch and reduce the quality of deep silicon etching

[0007] In order to avoid the production of micromasks or silicon grass, in the prior art, the etching step is usually carried out at a lower process pressure, but due to the use of a lower process pressure, the silicon etching rate will be reduced, thereby reducing Etching selectivity ratio

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