KR101893056B1 - Mems microphone chip structure and microphone package - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MEMS microphone chip structure and a package, the MEMS microphone chip structure and the package being mounted on a PCB substrate, A first insulating layer formed on the substrate and forming at least one exhaust hole in a horizontal direction; A diaphragm formed on the insulating film; A second insulating layer spaced apart from the first insulating layer and formed on the substrate higher than the height of the diaphragm; And a back plate formed on the second insulating film and having a plurality of through holes.

Description

[0001] MEMS MICROPHONE CHIP STRUCTURE AND MICROPHONE PACKAGE [0002]

The present invention relates to a microphone chip structure, and more particularly, to an improved MEMS microphone chip structure capable of improving sensitivity and acoustic characteristics and a microphone package using the same.

A microphone is a device that converts an acoustic signal into an electric signal, and is used in an acoustic device, a communication device, a medical device, or the like. As the various devices with built-in microphones become smaller in size, miniaturization of microphones is required. In response to these demands, the development of MEMS microphones is being actively pursued.

MEMS microphones have become very popular for their performance and production efficiency because they can be miniaturized and can be separated into separate production processes. MEMS microphones are fabricated using surface mount technology (SMT) and semiconductor processing technology using electromechanical systems (MEMS) technology.

The micro electro machining systems (MEMS) process can produce thin films with stable and adjustable physical properties based on semiconductor process technology, and it is possible to realize compact and inexpensive, high performance microphone chips by batch process. Also, since it can be assembled and operated at a higher temperature than a conventional electret condenser microphone, there is an advantage that a MEMS microphone package can be assembled by using a surface mount (SMD) equipment and technology which are used in the past.

FIG. 1 is a side sectional view showing the structure of a conventional MEMS microphone chip structure. FIG. 2 is a plan view of a back plate (see FIG. 2A) and a diaphragm (FIG. Fig.

As shown in FIGS. 1 and 2, a conventional MEMS microphone chip structure includes a microphone chip substrate having a back chamber formed at a central portion of a PCB substrate at a lower end of a package, a diaphragm having a vent hole formed at an upper portion of the insulating film and the insulating film, And a back plate having a plurality of through holes.

As shown in FIGS. 1 and 2, a conventional MEMS microphone chip structure includes a microphone chip substrate having a back chamber formed at a central portion of a PCB substrate at a lower portion of a package, a microphone chip substrate having a plurality of vent holes vent hole formed therein and a back plate having a plurality of through holes.

As described above, the conventional MEMS microphone chip structure has a plurality of vent holes formed in the diaphragm itself so that the air passes through the inside and the outside of the back chamber to form an air pressure balance. However, The vibration area due to the sound pressure due to the size can not be sufficiently secured, and there is a possibility that noise or the like is likely to occur and the sensitivity is low.

That is, when the number of the exhaust holes on the diaphragm is large or the diameter is large, the electric capacity formed by the area of the back plate and the diaphragm becomes small, which lowers the sensitivity and deteriorates the characteristics of the low frequency band. When the number is small or the diameter is small, the sensitivity of the diaphragm becomes high, but the air equilibrium is insufficient and an air resistance is generated in the back chamber, resulting in an abnormal reaction speed and sensitivity.

Korean Registered Patent No. 10-1496192 (Registered Date: February 17, 2015) Korean Patent Laid-Open Publication No. 10-2011-0025697 (public date: March 10, 2011)

The MEMS microphone chip structure and the microphone package according to the present invention have the following problems.

First, the present invention provides a MEMS microphone chip structure capable of improving sensitivity and acoustic characteristics, and a microphone package using the same.

Second, the present invention is to provide a MEMS microphone of good quality that can reduce the occurrence of noise and improve sensitivity characteristics and stability.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus and method for controlling the same.

According to a first aspect of the present invention, there is provided a MEMS microphone chip structure, comprising: a substrate mounted on a PCB substrate and having a back chamber formed at a lower center thereof; A first insulating layer formed on the substrate to form at least one exhaust hole penetrating the inside and the outside in a horizontal direction; A diaphragm formed on the insulating film; A second insulating layer spaced apart from the first insulating layer and formed on the substrate higher than the height of the diaphragm; And a back plate formed on the second insulating film and having a plurality of through holes.

It is preferable that the diaphragm does not have an exhaust hole and that the first insulating film and the second insulating film are made of silicon oxide, silicon nitride, or aluminum nitride, and the diaphragm is made of silicon (Si) An oxide film, or a polysilicon (Poly Si) film.

It is preferable that at least one of the exhaust holes is formed symmetrically with respect to the center of the exhaust hole and that the diameter of the exhaust hole increases toward the inner side or the outer side of the exhaust hole, And a third insulating layer for fixing the diaphragm.

According to a second aspect of the present invention, there is provided a MEMS microphone package comprising: a PCB substrate; A substrate adhered to the PCB substrate and having a back chamber formed at a lower center thereof; A first insulating layer formed on the substrate and forming at least one exhaust hole penetrating the inside and the outside in a horizontal direction; a diaphragm formed on the insulating layer; And a back plate formed on the second insulating film and having a plurality of through holes, the MEMS microphone chip structure comprising: And a case bonded to the PCB substrate to form a space for receiving the MEMS microphone chip structure.

It is preferable that the diaphragm does not have an exhaust hole and that the first insulating film and the second insulating film are any one of silicon oxide, silicon nitride, and aluminum nitride, Are formed symmetrically.

It is preferable that the exhaust hole has a larger opening diameter toward the inner side or the outer side and further includes a third insulating film formed around the outer edge of the diaphragm and above the first insulating film and for fixing the diaphragm Do.

The MEMS microphone chip structure and the microphone package according to the present invention have the following effects.

First, the present invention forms a passageway or an exhaust hole connected to the outside of the acoustic chamber in the insulating film connecting the diaphragm and the substrate, thereby reducing the occurrence of noise due to the exhaust hole formed in the center portion of the conventional diaphragm, And a microphone package using the same.

Second, the present invention provides an improved MEMS device capable of enhancing stability and improving sensitivity and acoustic characteristics by forming an exhaust hole in an insulating film and depositing an insulating film for fixing the diaphragm, thereby easily balancing the internal and external air pressures of the back chamber, Provides a microphone.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a side sectional view showing the structure of a conventional MEMS microphone chip structure.
FIG. 2 is a view showing a configuration of a back plate and a diaphragm used in a conventional MEMS microphone chip structure.
3 is a side view of a MEMS microphone chip structure according to an embodiment of the present invention.
FIGS. 4 and 5 are schematic views illustrating a lamination structure of a diaphragm and a first insulating film in which an exhaust hole of a MEMS microphone chip structure is formed, according to another embodiment of the present invention.
6 is a side sectional view showing the structure of a MEMS microphone chip structure as another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Wherever possible, the same or similar parts are denoted using the same reference numerals in the drawings.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto.

Means that a particular feature, region, integer, step, operation, element and / or component is specified and that other specific features, regions, integers, steps, operations, elements, components, and / It does not exclude the existence or addition of a group.

All terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

3 is a side view of a MEMS microphone chip structure according to an embodiment of the present invention. 3, a MEMS microphone chip structure according to an embodiment of the present invention includes a substrate 100 made of a silicon (Si) material, which is formed on an upper surface of a PCB substrate and forms a back chamber at a central portion thereof, A first insulating layer 200 formed on the substrate 100 and having at least one exhaust hole 250 penetrating the inside and the outside in the horizontal direction; And a plurality of through holes 550 formed on the second insulating film 400 and the second insulating film 400 formed apart from the first insulating film 200 by the diaphragm 300 And a back plate 500 (back plate).

As described above, in the embodiment of the present invention, the passage or exhaust hole 250 connected to the outside of the acoustic chamber in the horizontal direction is formed in the insulating film connecting the diaphragm 300 and the substrate 100, Provided is a chip structure capable of reducing the occurrence of noise due to the exhaust hole (250), converting sound into vibration of the diaphragm (300) without distortion, and converting the vibration into an electric signal to provide a high quality MEMS microphone.

Since the air in the back chamber is freely moved in and out of the back chamber and the sound pressure fluctuation due to the vibration of the diaphragm 300 can be rapidly reached in the equilibrium state, The characteristics can be improved.

Here, the substrate 100 is a silicon (Si), preferably a material, and the first insulating film 200 and the second insulating film 400 is a silicon oxide (S _i O), silicon nitride (SiN) or aluminum nitride (AlN ) Is preferably made of a material.

It is preferable that the diaphragm 300 is made of at least one of a nitride film including silicon (Si), an oxide film, and a polysilicon film. By using a material having an elastic force, So as to enhance the sensitivity of the microphone.

In addition, the diaphragm 300 used in the MEMS microphone chip structure according to the embodiment of the present invention uses the diaphragm 300 without the exhaust hole 250.

The diaphragm or diaphragm used in the conventional MEMS microphone chip forms an exhaust hole in the center portion or a plurality of exhaust holes around the periphery so as to balance the outside air pressure and the inside air pressure.

However, as described above, when the number of the exhaust holes on the diaphragm is large or the diameter is large, there is a problem that the electric capacity formed by the area of the back plate and the diaphragm becomes small, the sensitivity decreases and the characteristic of the low frequency band deteriorates In the embodiment of the present invention, at least one passageway or exhaust hole 250 is formed in the insulating film formed between the substrate 100 and the diaphragm 300 without forming the exhaust hole 250 in the diaphragm 300 So as to form the inner and outer air pressure equilibrium.

As described above, the MEMS microphone structure according to the embodiment of the present invention using the diaphragm 300 without the exhaust hole 250 can reduce the noise generated by the exhaust hole 250 formed in the conventional diaphragm 300 It is possible to provide an improved MEMS microphone with high sensitivity by eliminating the problem that the receiving area is reduced by the exhaust hole 250 and the sensitivity is lowered.

3, the MEMS microphone chip structure according to the embodiment of the present invention has a structure in which a first insulating layer 200 formed between a substrate 100 and a diaphragm 300 extends in a horizontal direction It is preferable that the exhaust hole 250 formed in the conventional diaphragm 300 performs a function.

The MEMS microphone chip structure according to an embodiment of the present invention includes a first insulating layer 200 formed between the diaphragm 300 and the substrate 100 and a second insulating layer 400 spaced apart from the side surface of the diaphragm 300, 300 to form a backing structure of the back plate 500 spaced apart therefrom. Since the second insulating layer 400 is formed apart from the first insulating layer 200 in the outward direction with the function of the backing layer of the back plate 500, 250 are formed to have a structure capable of securing a space through which the air moves through the back plate 500 to the outside, air can be equally passed through the inside and outside of the back plate 500 and air equilibrium can be achieved .

4 and 5 are schematic views showing a laminated structure of a diaphragm 300 and a first insulating film 200 in which an exhaust hole 250 of a MEMS microphone chip structure is formed, according to another embodiment of the present invention.

4, the first insulating layer 200 applied to the MEMS microphone chip structure according to the embodiment of the present invention includes at least one exhaust hole 250 for allowing air to flow in and out of the back chamber, It is formed parallel to the inside and outside. At least one or more of the exhaust holes 250 may be formed. In order to induce a uniform and stable flow to the inside and the outside of the back chamber, it is preferable to construct at least one pair symmetrically from the center.

The first insulating layer 200 is formed with four passageways or exhaust holes 250 connecting the inside and the outside of the first insulating layer 200, and each of the exhaust holes 250 may be positioned at a symmetrical position with respect to the center. In addition, it is needless to say that the first insulating film can be formed in various shapes, asymmetrical shapes, and exhaust holes arranged in an asymmetrical shape corresponding to the shape of the first insulating film. It is possible to arrange all of the exhaust holes that facilitate the flow of air.

The passage or exhaust hole 250 functions as an air passage connecting the inside and the outside of the back chamber in a horizontal direction, and the sectional shape may be formed in various shapes.

5, as another embodiment, the shape of the passage or exhaust hole 250 formed in the first insulating film 200 is preferably a tapered structure in which the diameter of the end surface increases toward the center of the back chamber or toward the outer side . This is because the air can flow smoothly to the inside and the outside of the back chamber, so that air equilibrium can be achieved more stably.

6 is a side sectional view showing the structure of a MEMS microphone chip structure as another embodiment of the present invention.

6, a MEMS microphone chip structure according to an embodiment of the present invention is mounted on a PCB substrate. The MEMS microphone chip structure includes a substrate 100 having a back chamber formed at a lower center of the substrate 100, (300) formed on the insulating film (200), and a second insulating film (300) formed on the first insulating film (200) and spaced apart from the first insulating film A second insulating layer 400 formed on the substrate 100 higher than the height of the diaphragm 300 and a second insulating layer 400 formed on the periphery of the outer edge of the diaphragm 300 and on the first insulating layer 200, And a back plate 500 formed on the second insulating layer 400 and having a plurality of through holes 550 formed therein.

6 is the same as that of the embodiment of FIG. 3 except that the first insulating layer 200 and the third insulating layer 600 are formed at the ends of the diaphragm 300 to fix the diaphragm 300, The third insulating layer 600 has a structure in which the end portion of the diaphragm 300 and the first insulating layer 200 are deposited and deposited. The diaphragm 300 is fixed, And durability can be improved.

As another embodiment of the present invention, the MEMS microphone package includes a PCB substrate; A substrate 100 bonded to the PCB 100 and having a back chamber formed at a lower center thereof; A first insulating layer 200 formed on the substrate 100 to form at least one exhaust hole 250 penetrating the inside and the outside in the horizontal direction, a diaphragm 300 formed on the insulating layer, A second insulating layer 400 spaced apart from the first insulating layer 200 and formed on the substrate 100 higher than a height of the diaphragm 300 and a second insulating layer 400 formed on the second insulating layer 400 A MEMS microphone chip structure including a back plate (500) having through holes (550) formed therein; And a case connected to the PCB substrate to form a space for accommodating the MEMS microphone chip structure (not shown). [0030] The embodiment of the present invention as described above is similar to the embodiment of FIG. 3 or 6 And a MEMS microphone package for attaching the MEMS microphone chip structure to the PCB substrate and covering the case.

The embodiments and the accompanying drawings described in the present specification are merely illustrative of some of the technical ideas included in the present invention. Accordingly, the embodiments disclosed herein are for the purpose of describing rather than limiting the technical spirit of the present invention, and it is apparent that the scope of the technical idea of the present invention is not limited by these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: substrate 200: first insulating film
250: exhaust hole 300: diaphragm
400: second insulating film 500: back plate

Claims (13)

A substrate mounted on the PCB substrate, the substrate having a back chamber formed at a lower center thereof;
A first insulating layer formed on the substrate and forming at least four even-numbered exhaust holes symmetrically paired with the center passing through the inside and the outside in the horizontal direction;
A diaphragm formed on the first insulating film and not including an exhaust hole;
A second insulating layer spaced apart from the first insulating layer and formed on the substrate higher than the height of the diaphragm; And
And a back plate formed on the second insulating film and having a plurality of through holes.
The exhaust hole
And the opening diameter increases toward the inner side or the outer side. delete The method according to claim 1,
Wherein the first insulating film is silicon nitride or aluminum nitride,
Wherein the second insulating film is silicon oxide. The method according to claim 1,
The diaphragm includes:
Wherein the microstructure is poly-silicon (Poly-Si). delete delete delete delete delete delete delete delete delete

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