Semiconductor structure and preparation method thereof

Abstract

The invention relates to a semiconductor structure and a preparation method thereof. The semiconductor structure includes a substrate provided with a cavity; the substrate is filled with a filling layer, a barrier layer is arranged on the surface of the filling layer, and at least part of the surface of the filling layer is exposed outside, wherein the barrier layer is boron-doped silicon oxide ornon-doped silicon oxide; the filling layer is phosphorus-doped silicon oxide or non-doped silicon oxide; at least one of the barrier layer and the filling layer is doped silicon oxide. The differenceof the corrosion rates of the barrier layer and the filling layer is enlarged by utilizing the difference of the boron/phosphorus doping proportions in the filling layer and the barrier layer, so that the corrosion selectivity of a corrosive liquid to the filling layer in the cavity is improved, the pattern of the cavity is more regular, and meanwhile, the corrosion defects of other functional layers, particularly the barrier layer, are reduced.

Description

technical field [0001] The invention relates to the field of semiconductor production, in particular to a semiconductor structure and a preparation method thereof. Background technique [0002] Silicon oxide is one of the basic materials of silicon-based integrated circuit manufacturing technology and plays a very important role in integrated circuits. Silicon oxide can be used as gate oxide layer, field oxide layer, shielding layer, insulating layer and pad oxide layer, doping barrier layer, sacrificial layer, etc. in silicon-based integrated circuits. [0003] In the filter chip, the cavity is very common, and it is one of the important structures to realize the resonance function. In the filter process, in order to protect the cavity formed in the early stage from being polluted by various functional layer materials deposited or grown later, silicon oxide is filled in the cavity pattern as a sacrificial layer (or filling layer) for protection. Layers are removed by wet ...

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Problems solved by technology

The prior art has the following technical problems in the wet etching of the silicon oxide filling layer: the corrosion selectivity of the etchant to the barrier layer on the surface of the filter chip structure and the silicon oxide filling layer is low, so that on the one hand, it is easy to cause corrosion to the structure protected by the barrier layer Sexual defects, on the other hand, the filling layer is not corroded thoroughly, resulting in the cavity pattern not up to standard

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