The preparation method of the acoustic sensor

Abstract

The invention discloses a method for preparing a sound sensor. The method comprises the following steps: providing a substrate; sequentially forming a first sacrificial layer, a second sacrificial layer, a vibration electrode, a third sacrificial layer, a fixed electrode film and a protective layer on the substrate; selectively etching the protective layer and the fixed electrode film to form a fixed electrode and a sound hole; selectively etching the substrate to form a substrate opening; removing the first sacrificial layer by adopting a first wet etching process; and removing the second sacrificial layer and the third sacrificial layer by adopting an ashing process to form the sound sensor. The method for preparing the sound sensor disclosed by the invention can be used for avoiding or reducing residual etching liquid in an air cavity, so as to improve the performance of the device.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for preparing an acoustic sensor. Background technique [0002] Microphones are found in a variety of devices, such as mobile phones and integrated circuit (IC) recorders. As the main device of the microphone, the sound sensor plays a vital role in the transmission of sound. At present, the air cavity in the acoustic sensor is usually prepared by the method of sacrificial layer release, such as Figure 1-Figure 9 As shown, the specific steps include: [0003] First, if figure 1 As shown, a substrate 100 is provided; [0004] Then, if figure 2 As shown, a first sacrificial layer 110 is formed on the substrate 100, and the material of the first sacrificial layer 110 is oxide; [0005] Next, if image 3 As shown, a vibrating electrode 120 is formed on the first sacrificial layer 110, and a crack 121 may be formed in the vibrating electrode 120, and the crack ...

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Problems solved by technology

[0012] However, since in the prior art, the first portion 110a of the first sacrificial layer 110 and the first portion 130a of the second sacrificial layer 130 are removed by a wet etching process, the etchant enters the sound holes 161 and The first sacrificial layer 110a and the second sacrificial layer 130a can only be contacted after the opening 101 of the substrate. After the first sacrificial layer 110a and the second sacrificial layer 130a are removed, part of the etching solution will remain in the air cavity 111 , thus affecting the performance of the acoustic sensor 1

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