Microphone and its manufacturing method

Abstract

The invention provides a microphone and a manufacturing method thereof. By adding grooves on the front side of the substrate, the thickness of the film layer material used to make the back cavity can be relatively increased, and the back cavity can be etched with a larger debugging space, which is advantageous. It is beneficial to increase the etching time from the direction of adjusting the process formula, thereby improving or eliminating the sharp corners formed on the front side of the substrate after the back cavity etching, and the sharp corners formed on the front side of the substrate after the back cavity etching still cannot pass through When the adjustment of the process formula is completely eliminated, the addition of the groove can increase the distance from the sharp corner on the front of the substrate to the diaphragm, so that the diaphragm cannot touch the sharp corner when vibrating, improving the reliability and good performance of the device. Rate. In addition, the addition of grooves on the front surface of the substrate helps to reduce the thickness of the first sacrificial layer on the periphery of the groove without sacrificing device performance, thereby facilitating the development of the microphone to a smaller size.

Description

technical field [0001] The invention relates to the technical field of semiconductor device manufacturing, in particular to a microphone and a manufacturing method thereof. Background technique [0002] Please refer to figure 1 , the existing manufacturing process of a MEMS (Micro-Electro-Mechanical System, Micro-Electro-Mechanical System) microphone includes: performing etching on the back side of the substrate 100 to open the substrate 100 to form an opening, during which the sacrificial layer 101 is used as The etch stop layer of the substrate 100 needs to have a certain thickness; and then part of the sacrificial layer 101 is etched and removed through the opening to form the back cavity 101a exposing the diaphragm 102, and after the back cavity 101a is formed, a certain amount of sacrificial layer 101 is required to remain The amount is used as a supporting wall for supporting the diaphragm 102. [0003] With the development of technology, MEMS microphones are develop...

AI Technical Summary

Problems solved by technology

However, in the manufacturing process of the above-mentioned MEMS microphone, on the one hand, after the back cavity 101a is formed, it is easy to form a sharp corner 100a at the position of the opening of the substrate 100 close to the diaphragm 102, so that the diaphragm 102 is easy to touch when vibrating. The sharp corner 100a will cause the diaphragm 102 to break, the device will fail, and the yield will be lost; on the other hand, if the sacrificial layer 101 is designed to be thin, it will pose a huge challenge to the etching and debugging of the back cavity 101a

[0004] In addition, since the sacrificial layer 101 is tiled on the front surface of the substrate 100, when the process recipe is adjusted, for example, a certain degree of over-etching is performed when etching the substrate 100 to form an opening to eliminate the sharp corner 100a, if The over-etching process causes the sacrificial layer 101 in the area of ​​the back cavity 101a to be etched open, thereby exposing the diaphragm 102, and then when the sacrificial layer 101 in the area of ​​the back cavity 101a is subsequently released through the opening, the diaphragm 102 will be abnormal

Moreover, the abnormality of the diaphragm will affect the performance of the device, and even cause the device to fail.

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