Disclosure of Invention
The invention provides a microphone packaging structure and a microphone system, which are used for improving the signal-to-noise ratio of the microphone packaging structure.
In a first aspect, an embodiment of the present invention provides a microphone package structure, including:
the MEMS chip comprises a substrate, an MEMS chip, an ASIC chip and a protective shell;
the MEMS chip and the ASIC chip are arranged on the substrate, the MEMS chip is electrically connected with the ASIC chip, and the ASIC chip is electrically connected with the substrate; the MEMS chip is used for converting an external sound signal into an electric signal, and the ASIC chip is used for processing the electric signal;
the protective shell is positioned on the substrate and covers the MEMS chip and the ASIC chip; the protective shell comprises a through hole;
the substrate comprises at least two hollow cavities, and the at least two hollow cavities are communicated with the back cavity of the MEMS chip.
In a second aspect, an embodiment of the present invention further provides a microphone system, including the microphone packaging structure described in the first aspect.
The microphone packaging structure provided by the embodiment of the invention comprises a substrate, a MEMS chip, an ASIC chip and a protective shell, wherein the MEMS chip and the ASIC chip are arranged on the substrate, the MEMS chip is electrically connected with the ASIC chip, the ASIC chip is electrically connected with the substrate, the MEMS chip is used for converting external sound signals into electric signals, the ASIC chip is used for processing the electric signals, the protective shell is positioned on the substrate, and covers the MEMS chip and the ASIC chip, the protective shell comprises a through hole, the substrate comprises at least two hollow chambers, the at least two hollow chambers are communicated with the back cavity of the MEMS chip, the volume of the back cavity of the MEMS chip is increased due to the arrangement of the at least two central control chambers, and then the signal to noise ratio of the microphone is improved, and the spacing body between the at least two central control cavities plays a supporting role, so that the hollow cavities are prevented from collapsing in the substrate pressing process and the MEMS chip mounting process, and the strength of the substrate and the microphone packaging structure is improved.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description will be given to specific embodiments, structures, features and effects of a microphone package structure and a microphone system according to the present invention with reference to the accompanying drawings and preferred embodiments.
An embodiment of the present invention provides a microphone packaging structure, including:
the MEMS chip comprises a substrate, an MEMS chip, an ASIC chip and a protective shell;
the MEMS chip and the ASIC chip are arranged on the substrate, the MEMS chip is electrically connected with the ASIC chip, and the ASIC chip is electrically connected with the substrate; the MEMS chip is used for converting an external sound signal into an electric signal, and the ASIC chip is used for processing the electric signal;
the protective shell is positioned on the substrate and covers the MEMS chip and the ASIC chip; the protective shell comprises a through hole;
the substrate comprises at least two hollow cavities, and the at least two hollow cavities are communicated with the back cavity of the MEMS chip.
The microphone packaging structure provided by the embodiment of the invention comprises a substrate, a MEMS chip, an ASIC chip and a protective shell, wherein the MEMS chip and the ASIC chip are arranged on the substrate, the MEMS chip is electrically connected with the ASIC chip, the ASIC chip is electrically connected with the substrate, the MEMS chip is used for converting external sound signals into electric signals, the ASIC chip is used for processing the electric signals, the protective shell is positioned on the substrate, and covers the MEMS chip and the ASIC chip, the protective shell comprises a through hole, the substrate comprises at least two hollow chambers, the at least two hollow chambers are communicated with the back cavity of the MEMS chip, the volume of the back cavity of the MEMS chip is increased due to the arrangement of the at least two central control chambers, and then the signal to noise ratio of the microphone is improved, and the spacing body between the at least two central control cavities plays a supporting role, so that the hollow cavities are prevented from collapsing in the substrate pressing process and the MEMS chip mounting process, and the strength of the substrate and the microphone packaging structure is improved.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative work belong to the protection scope of the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other embodiments that depart from the specific details disclosed herein, and it will be recognized by those skilled in the art that the present invention may be practiced without these specific details.
Next, the present invention is described in detail with reference to the schematic drawings, and in the detailed description of the embodiments of the present invention, the schematic drawings showing the structure of the device are not partially enlarged in general scale for convenience of description, and the schematic drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and height should be included in the actual fabrication.
Fig. 1 is a schematic diagram of a microphone package structure according to an embodiment of the present invention. As shown in fig. 1, the microphone package structure includes a substrate 100, a MEMS chip 200, an ASIC chip 300, and a protective case 400.
The MEMS chip 200 and the ASIC chip 300 are mounted on the substrate 100, the MEMS chip 200 is electrically connected to the ASIC chip 300, the ASIC chip 300 is electrically connected to the substrate 100, the MEMS chip 200 is used to convert an external sound signal into an electrical signal, and the ASIC chip is used to process the electrical signal. The protective case 400 is located on the substrate 100 and covers the MEMS chip 200 and the ASIC chip 300, the protective case 400 includes a through hole 410, the substrate 100 includes at least two hollow cavities 110, and the at least two hollow cavities 110 are in communication with the back cavity 210 of the MEMS chip 200.
Specifically, fig. 2 is a schematic top view of a substrate according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view along the broken line AA in fig. 2. Fig. 4 is a schematic sectional view along a dotted line BB in fig. 2. As shown in fig. 2, 3 and 4, the substrate includes three hollow chambers 110, the three hollow chambers 110 are all communicated with the opening 101 on the upper surface of the substrate 100, in the mounting process of the MEMS chip, the MEMS chip covers the opening 101, the MEMS chip is supported by the spacers between the hollow chambers 110, the downward pressure acting on the MEMS chip cannot easily cause the hollow chamber 110 to collapse, and meanwhile, in the processing process of the substrate, the hollow chamber 110 cannot collapse due to the existence of the spacer support.
It should be noted that the MEMS chip includes a vibrating membrane, and external sound can reach the vibrating membrane through the through hole on the protective case, and change the distance between the vibrating membrane and the back plate, thereby forming a capacitance change, and the ASIC chip converts the capacitance change into a change of a voltage signal, and then outputs the voltage signal after amplification. Specifically, the voltage signal may be transmitted to the outside of the microphone package structure through a line on the substrate.
It should be noted that fig. 2 only illustrates 3 circular hollow chambers by way of example and is not limited thereto, and in other embodiments of this embodiment, the number and shape of the hollow chambers may be in other cases.
The microphone package structure provided by the embodiment comprises a substrate, a MEMS chip, an ASIC chip and a protective shell, wherein the MEMS chip and the ASIC chip are arranged on the substrate, the MEMS chip is electrically connected with the ASIC chip, the ASIC chip is electrically connected with the substrate, the MEMS chip is used for converting external sound signals into electric signals, the ASIC chip is used for processing the electric signals, the protective shell is positioned on the substrate, and covers the MEMS chip and the ASIC chip, the protective shell comprises a through hole, the substrate comprises at least two hollow chambers, the at least two hollow chambers are communicated with the back cavity of the MEMS chip, the volume of the back cavity of the MEMS chip is increased due to the arrangement of the at least two central control chambers, and then the signal to noise ratio of the microphone is improved, and the spacing body between the at least two central control cavities plays a supporting role, so that the hollow cavities are prevented from collapsing in the substrate pressing process and the MEMS chip mounting process, and the strength of the substrate and the microphone packaging structure is improved.
With continued reference to fig. 1, the substrate 100 includes a first sub-substrate 121 and a second sub-substrate 122 stacked in sequence, the first sub-substrate 121 is located on one side of the second sub-substrate 122 close to the protective shell 400, the first sub-substrate 121 includes an opening 102, the second sub-substrate 122 includes at least two grooves 103, the at least two grooves 103 and the first sub-substrate 121 form at least two hollow cavities 110, and the at least two central control cavities 110 are communicated with the back cavity 210 of the MEMS chip through the opening 102.
Thus, the preparation process of the large-volume hollow chamber 110 with the smaller opening is simpler, only conventional groove preparation and plate adhesion are needed, no complex process is needed, and the size controllability of the hollow chamber is stronger.
Fig. 5 is a schematic diagram of another microphone package structure according to an embodiment of the present invention. As shown in fig. 5, on the basis of fig. 1, a step-up ring 500 is further disposed between the MEMS chip 200 and the substrate 100, and the back cavity 210 of the MEMS chip 200, the inner space of the step-up ring 500, and the at least two hollow cavities 110 communicate with each other.
It should be noted that the padding ring 500 is a ring structure, which can further increase the volume of the back cavity 210 of the MEMS chip 200, thereby achieving a higher signal-to-noise ratio.
It is understood that the electrical signal transmission between the MEMS chip 200 and the ASIC chip 300 is realized through the conductive wire 600 therebetween, and no electrical signal transmission exists between the MEMS chip and the ASIC chip and the substrate and the pad ring 500, so that the material of the pad ring 500 may be a conductive material or a non-conductive material, which is not limited in this embodiment. In addition, the height of the padding ring 500 can be set reasonably according to actual needs.
Optionally, the shape of the raised ring 500 is the same as the outer edge shape of the MEMS chip 200. In this way, the cross-sectional dimension of the inner space of the padding ring 500, which is communicated with the back cavity 210 of the MEMS chip 200, is the largest, which is beneficial to the increase of the size of the back cavity 210 of the MEMS chip 200.
For example, the material of the protective case 400 may be metal.
It should be noted that the metal has a high strength and can withstand a large impact, so as to prevent the MEMS chip 200 and the ASIC chip 300 from being damaged by an external force.
In the present embodiment, as shown in fig. 5, the MEMS chip 200 is electrically connected to the ASIC chip 300 through a wire 600, and the ASIC chip 300 is electrically connected to the substrate 100 through a wire 600.
It should be noted that the connection process of the wire 600 and the chip is simple, and can be realized only by a conventional soldering process, and the reliability is good, and in addition, the arrangement of the conductive 600 simplifies the circuit structure on the substrate 100, thereby simplifying the preparation process of the substrate.
Alternatively, the surface of the ASIC chip 300 remote from the substrate 100 may be provided with an adhesive film.
It should be noted that the raw material of the adhesive film may be glue, which can protect the solder joints in the ASIC chip and prevent dust.
Illustratively, the shape of the through-hole 410 may be circular.
It should be noted that the existing production line has a mature process for forming a circular through hole on a metal layer, and the circular shape of the through hole 410 is beneficial to simplifying the preparation process of the through hole 410.
Fig. 6 is a schematic structural diagram of a microphone system according to an embodiment of the present invention. As shown in fig. 6, the microphone system 10 includes a microphone package 11 according to any of the embodiments of the present invention. The microphone system 10 provided in the embodiment of the present invention includes the microphone package structure 11 according to any embodiment of the present invention, has the technical features of the microphone package structure 11 provided in any embodiment of the present invention, and has the same or corresponding beneficial effects as the microphone package structure 11 included therein, which are not described herein again.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.