A kind of mems microphone and its making method

Abstract

The invention provides an MEMS microphone and a production method thereof. The microphone comprises a substrate with a first surface and a second surface opposite to the first surface; a capacitor structure positioned on the first surface of the substrate, wherein the capacitor structure comprises a cavity, fixed electrodes positioned in the cavity, a vibrating diaphragm opposite to the fixed electrodes, sound holes distributed at intervals in the fixed electrodes, and amplitude limiting structures positioned in the sound holes, wherein polycrystalline silicon spacing layers are arranged around the fixed electrode; and a back cavity positioned in the substrate, wherein the top of the back cavity is exposed from the second surface of the substrate, and the capacitor structure is exposed from the bottom of the back cavity. According to the MEMS microphone and the production method thereof provided by the invention, the problem that in the prior art, when oxide spacing layers are used forimproving APT performance, after a final buffer oxide etching technology, a side excavating phenomenon occurs in an area adjacent to the connection end of the fixed electrode due to siphonic effect brought by the oxide spacing layers is solved.

Description

technical field [0001] The invention relates to a micro-electro-mechanical system technology, in particular to a MEMS microphone and a manufacturing method thereof. Background technique [0002] In recent years, with the rapid development of semiconductor technology, electronic products tend to be designed in the direction of miniaturization and thinning. Among the products in the field of electroacoustics, microphones are used to convert sound waves into electrical signals, and many electronic products currently on the market have been equipped with micro-electro-mechanical (MEMS: Micro-electro-mechanical system) microphones; MEMS microphones are used to Microelectromechanical system technology is a micro-microphone made by etching a pressure-sensing diaphragm on a semiconductor. Compared with the common electret microphone (ECM), the MEMS microphone has stronger heat resistance, anti-vibration, and anti-radio frequency interference. Ability. Moreover, the MEMS microphone...

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Problems solved by technology

[0003] MEMS microphones need to be tested by air pressure (APT: Air Pressure Test) during production. The MEMS microphones produced by the existing technology cannot meet the needs of customers when performing APT tests. The APT test data show that the thicker the oxide spacer, the better its APT performance; although setting the oxide spacer around the fixed electrode solves the problem of APT testing, the buffer oxide in the final cavity formed After the BOE process, due to the siphon effect brought by the oxide spacer layer, the undercut phenomenon appeared in the area near the connection end of the fixed electrode

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