Electrode flatness evaluation structure and preparation method of capacitive silicon microphone

Abstract

The invention relates to a capacitive silicon microphone electrode flatness assessment structure which comprises a substrate, a first medium layer, a lower electrode, an upper electrode and a supporting body. The first medium layer is formed on the substrate. The lower electrode is placed on the first medium layer. The upper electrode is formed above the lower electrode with an air gap as an interval. The supporting body is used for supporting and fixing the upper electrode. The lower electrode comprises a plurality of first alignment pieces, the upper electrode comprises a plurality of second alignment pieces, the first alignment pieces and the second alignment pieces are of a central symmetry structure, the first alignment pieces correspond to the second alignment pieces in a one-to-one mode, and the centers of the first alignment pieces and the centers of the second alignment pieces coincide. The capacitive silicon microphone electrode flatness assessment structure can be directly and effectively used for assessing whether polycrystalline silicon films of the upper electrode and the lower electrode are flat.

Description

technical field [0001] The invention relates to the field of semiconductor processing and manufacturing, and more specifically relates to a capacitive silicon microphone electrode flatness evaluation structure and a preparation method thereof. Background technique [0002] A capacitive silicon microphone is a microphone manufactured through a surface (such as a silicon substrate) process compatible with integrated circuit manufacturing. Using the continuous shrinking CMOS process technology, it can be made very small and is widely used in mobile phones and notebooks. , Bluetooth headsets, cameras and other portable electronic products. [0003] Such as figure 1 As shown, the MEMS microphone includes a silicon substrate 10, a back cavity 101 that penetrates up and down is arranged on the substrate, and a parallel plate capacitor composed of an upper electrode 103 and a lower electrode 102 is arranged above the substrate, and the lower electrode 102 is usually formed by a fix...

AI Technical Summary

Problems solved by technology

[0004] In actual production, the upper and lower electrodes of MEMS microphones are mostly made of polysilicon thin films; however, when the two layers of thin films of the upper and lower electrodes stick together, it will lead to a low product yield; and there is no mechanism in the production process. It is impossible to measure the flatness of the layered film, and it is impossible to evaluate whether there will be adhesion problems between them, so that it cannot provide help for the improvement of the production process and the increase of the yield rate.

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