CN201403194Y - Mems microphone - Google Patents

Abstract

The utility model relates to the field of microphones, in particular to a MEMS microphone which comprises an upper cover plate, a shell wall and a base plate, wherein a MEMS chip is arranged in a cavity composed of the upper cover plate, the shell wall and the base plate, a baffle is arranged on the base plate, and can divide the cavity into at least two sub-cavities, a sound inlet hole and the MEMS chip are respectively arranged in different sub-cavities, the inner portion of the base plate is provided with an acoustic channel which penetrates through the base plate to communicate with a sunken acoustic cavity and the cavity with the sound inlet hole, thus sound energy can be transmitted to the back of an MEMS diaphragm through the acoustic channel, a space on the back end of the MEMS chip is used as a back acoustic cavity of the MEMS chip, thereby enabling the back acoustic cavity of the MEMS chip not to be limited by the base plate, and the enlarged back acoustic cavity is beneficial for increasing the frequency response performance and the signal-to-noise ratio of the microphone and improving the whole performances of the microphone.

Description

MEMS microphone

【Technical field】

The utility model relates to the field of microphones, in particular to a MEMS microphone.

【Background technique】

With the development of wireless communication, there are more and more mobile phone users around the world. The requirements of users for mobile phones are not only satisfied with calls, but also to be able to provide high-quality call effects, especially the development of mobile multimedia technology at present. The sound directivity and noise reduction ability are strengthened, and the microphone of the mobile phone is used as the voice pickup device of the mobile phone, and its design directly affects the call quality.

The microphone that is currently used more and has better performance is a MEMS (Micro-Electro-Mechanical-System Microphone) microphone, as shown in Figure 1; ~, surrounding and supporting the upper cover plate 10~; a substrate 30~, on which are installed MEMS chips 50~ electrically connected to each other, application-specific integrated circuit ASIC chips 40~ integrated with preamplifiers and other passive components, said The substrate 30~ supports the shell wall 20~ and the upper cover plate 10~; the MEMS chip 50~ is attached to the substrate 30~, so that a microphone is formed between a depression on the MEMS chip 50~ and the base surface of the substrate 30~ Back vocal cavity 51~. The above only provides a structure of a silicon-based microphone. The space for forming the back acoustic cavity 51~ of the microphone between the MEMS chip 50~ and the substrate 30~ of this design is very limited, and the contribution to performance improvement is also very small, which is bound to be the smallest Limiting the frequency response performance of the sensor on the MEMS chip 50~ is not conducive to improving the signal-to-noise ratio, not to mention that the sound energy is directly incident on the silicon-based diaphragm, and it will also be affected by external light and electromagnetic interference, which will affect the microphone. performance and lifespan.

【Content of utility model】

The purpose of the utility model is to solve the problems of low frequency response performance and small signal-to-noise ratio of the microphone itself, and propose a MEMS microphone that increases the sound input from the back.

A MEMS microphone, comprising an upper cover with an acoustic hole, a shell wall surrounding and supporting the upper cover, a substrate supporting the shell wall and the upper cover, and a cavity formed by the substrate, the shell wall, and the upper cover There are integrated circuit chips and MEMS chips inside, and a partition is arranged on the substrate. The partition divides the cavity into at least two sub-cavities. The sound inlet and the MEMS chip are respectively located in different sub-cavities, and the MEMS chip has a concave acoustic cavity. , an acoustic channel is provided inside the substrate, and the recessed acoustic cavity communicates with the sound inlet through the acoustic channel.

Preferably, at least a section of the acoustic channel runs parallel to the substrate.

The MEMS chip and the integrated circuit chip are located in different sub-cavities.

The MEMS microphone of the utility model comprises an upper cover plate, a shell wall, and a base plate, and a MEMS chip is installed in the cavity formed by it, and a partition is arranged on the base plate, and the partition divides the cavity into at least two sub-cavities for further The acoustic hole and the MEMS chip are respectively located in different sub-cavities. There is an acoustic channel inside the substrate, and the acoustic channel passes through the substrate to connect with the concave acoustic cavity and the cavity with the sound inlet hole, so that the sound energy is transferred from the acoustic channel to the MEMS membrane. The back of the chip, and the space at the back end of the MEMS chip becomes the back acoustic cavity of the MEMS chip, so that the back acoustic cavity of the MEMS chip is no longer limited by the substrate. The enlarged back acoustic cavity is conducive to improving the frequency response performance and signal-to-noise ratio of the microphone, and improving the overall performance of the device. performance.

【Description of drawings】

Fig. 1 is the sectional schematic diagram of prior art MEMS microphone;

Fig. 2 is the sectional schematic diagram of MEMS microphone of the present utility model;

FIG. 3 is a schematic top view and cross-sectional view of the MEMS microphone of the present invention.

【Detailed ways】

The specific structure of the utility model will be described in detail below in conjunction with the accompanying drawings.

The MEMS microphone of the utility model is mainly used in mobile phones to receive acoustic signals and convert the acoustic signals into electrical signals. As shown in Figure 2, it is a preferred embodiment of the utility model, which includes an upper cover plate 10 with an inlet sound hole 11, a shell wall 20, surrounding and supporting the upper cover plate 10; a base plate 30, the described The base plate 30 supports the shell wall 20 and the upper cover plate 10, and the base plate 30 is combined with the shell wall 20 and the upper cover plate 10 to form a cubic cavity; inside the cavity, an ASIC chip 40 and a MEMS chip are installed on the surface of the base plate 30 50, the upper cover is provided with a flat partition 23, and the partition 23 divides the cavity formed by the upper cover 10, the shell wall 20, and the base plate 30 into a first cavity 21 and a second cavity 22, of course The separated sub-cavity is not limited to two; wherein the sub-cavity with the sound hole 11 is the second cavity 22, and the sub-cavity with the MEMS chip 50 inside is the first cavity 21, that is to say, the sound inlet The hole 11 and the MEMS chip 50 are respectively located in different cavities; due to the characteristics of the MEMS chip 50's own structure, the MEMS chip 50 is installed on the inner surface of the substrate 30 to form a concave acoustic cavity 51, and the inside of the substrate 30 is provided with an acoustic channel 31, and the acoustic channel 31 One end 32 communicates with the recessed acoustic cavity 51, and the other end 33 communicates with the second cavity 22. The sound wave enters from the sound inlet hole 11, passes through the second cavity 22, and then transmits to the MEMS chip 50 through the acoustic channel 31, acting on the MEMS membrane. The back of the chip, and the space at the back end of the MEMS chip becomes the back acoustic cavity of the MEMS chip, so that the back acoustic cavity of the MEMS chip is no longer limited by the substrate, which undoubtedly expands the back acoustic cavity of the MEMS chip. Obviously, the space of the back acoustic cavity is obviously larger than that shown in the figure. 1 the space of the back acoustic cavity 51 ~ of the microphone, then the back acoustic cavity is not limited by the substrate 30, and the enlarged back acoustic cavity 52 makes the frequency response characteristics and open circuit sensitivity of the micro-electromechanical system microphone after packaging the best, which is conducive to improving the microphone The signal-to-noise ratio improves the overall performance of the device.

In addition, as shown in FIG. 3 , for simple and reliable packaging, the MEMS chip 50 and the integrated circuit chip 40 can be located in different sub-cavities, and the middle section of the acoustic channel 31 is parallel to the substrate 30, which is convenient for microphone packaging.

The above are only preferred embodiments of the present utility model, and the protection scope of the present utility model is not limited to the above-mentioned embodiments, but any equivalent modification or change made by those of ordinary skill in the art according to the content disclosed in the present utility model, All should be included in the scope of protection described in the claims.

Claims (3)

1. MEMS microphone, comprise the upper cover plate of being with sound hole, one around and the shell wall, that supports upper cover plate support the substrate of shell wall and upper cover plate, be provided with integrated circuit (IC) chip and MEMS chip in the cavity that substrate and shell wall, upper cover plate constituted, it is characterized in that: substrate is provided with dividing plate, dividing plate is divided at least two sub-cavitys with cavity, sound hole lays respectively at different sub-cavitys with the MEMS chip, the MEMS chip has the depression operatic tunes, substrate inside is provided with acoustical passage, and the depression operatic tunes communicates by this acoustical passage with sound hole.

2, MEMS microphone according to claim 1 is characterized in that: this acoustical passage has at least one section trend parallel with substrate.

3, MEMS microphone according to claim 1 is characterized in that: described MEMS chip is positioned at different sub-cavitys with integrated circuit (IC) chip.

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