A MEMS microphone and a formation method thereof

Abstract

Provided are a MEMS microphone and a formation method thereof. The formation method comprises: providing a first substrate comprising a first surface and a second surface, wherein, the first substrate comprises at least one conductive layer, which is located at a side of the first surface of the first substrate; providing a second substrate comprising a third surface and a fourth surface, wherein, the second substrate comprises a second base and a sensitive electrode, and comprises a sensitive area, in which the sensitive electrode is located at a side of the third surface of the second substrate; fixing the first surface of the fist substrate and the third surface of the second substrate each other; thereafter, removing the second base, and forming a fifth surface opposite to the third surface of the second substrate; forming an empty cavity between the first substrate and the sensitive area of the second substrate; and forming, from a side of the fifth surface of the second substate, a first conductive plug penetrating to the at least one conductive layer. The MEMS microphone is improved in performance and reliability, is reduced in size, and is lowed in process cost.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a MEMS microphone and a forming 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 available on the market are equipped with MEMS (micro-electromechanical) microphones. Compared with common electret microphones (ECM), MEMS microphones are more resistant to heat, vibration, and radio frequency interference. [0003] MEMS microphones are miniature microphones made by etching pressure-sensing diaphragms on semiconductors through micro-electro-mechanical systems technology. They are commonly used in mobile phones, earphones, laptops, cameras and cars...

AI Technical Summary

Problems solved by technology

[0005] In the existing MEMS microphone manufacturing method, the process of integrating the microphone chip and the CMOS circuit process is quite different, and it is difficult to achieve monolithic integration.

At the same time, when a CMOS circuit and a microphone structure are fabricated on a single substrate, the existence of the microphone structure hinders the manufacture of the CMOS circuit, and the existence of the CMOS circuit on the same substrate also causes difficulties in the manufacture of small-sized microphone structures.

Therefore, the manufacturing process of using a single substrate as a CMOS circuit and a microphone structure is more complicated, and the size of the formed device is larger, resulting in an increase in manufacturing cost.

[0006] When making an integrated microphone structure and CMOS circuit on a single substrate, if the parts of the microphone structure are made first, and then the CMOS circuit is made, the process of manufacturing the microphone structure often affects the substrate, resulting in the difficulty of CMOS circuit production. reduce

If the CMOS circuit is made first, and then the microphone structure is made, the existence of the CMOS circuit has great restrictions on the material selection and process temperature of the microphone structure, thereby seriously reducing the performance of the microphone structure.

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