Package substrate, MEMS microphone, electronic device, and packaging carrier tape

Abstract

The invention provides a packaging substrate, an MEMS microphone, an electronic device and a packaging carrier tape. The packaging substrate comprises a first packaging layer and a second packaging layer, wherein the first packaging layer is provided with at least one first hollow area; one surface, deviating from the first packaging layer, of the second packaging layer is provided with a mounting area, and the mounting area is used for mounting a sound pickup chip; the flexible circuit board is arranged between the first packaging layer and the second packaging layer, electrical connection pins are arranged on the face, facing the second packaging layer, of the flexible circuit board, the electrical connection pins are exposed out of the first hollowed-out area, the sound pickup chip is electrically connected with the electrical connection pins, the hardness of the flexible circuit board is lower than that of the first packaging layer, and the hardness of the sound pickup chip is lower than that of the second packaging layer. The hardness of the flexible circuit board is lower than that of the first packaging layer, and the packaging substrate comprises the flexible circuit board, so that the stress buffering effect can be realized, and the MEMS microphone comprising the packaging substrate has good deformation resistance.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a packaging substrate, a MEMS microphone, an electronic device, and a packaging carrier tape. Background Art

[0002] Micro-Electro Mechanical System (MEMS) refers to a sensor device with dimensions in millimeters or even smaller, and its internal structure is generally in the micron or even nanometer scale, which is an independent intelligent system. A MEMS microphone refers to a microphone manufactured based on MEMS technology. Compared with the traditional Electret Capacitance Microphone (ECM), it has significant advantages in terms of performance, reliability, and manufacturability. For example, MEMS microphones can be reflow soldered, but ECMs cannot; the sensitivity difference of MEMS microphones under temperature influence is smaller than that of ECMs; the vibration sensitivity of MEMS microphones is lower than that of ECMs; the frequency response between components of MEMS microphones is more uniform. Therefore, MEMS microphones have been widely used in fields such as smart phones, tablet computers, hearing aids, automobiles, headphones, and smart homes.

[0003] A MEMS microphone is a miniature microphone, so the accuracy requirements for its internal packaging are higher. Especially with the rise of some miniaturized audio devices such as True Wireless Stereo (TWS) headphones, the packaging size of MEMS microphones is getting smaller and smaller. Therefore, the internal packaging structure of MEMS microphones is becoming more and more compact, and the packaging difficulty is further increased. Moreover, the packaging substrate of MEMS microphones is generally very thin and easily deformed by force. Especially for small-sized packaging substrates, this deformation is more likely to be transmitted to the sensor chip, such as the MEMS chip, under pressure, which has a negative impact on the working state of the sensor chip.

[0004] Therefore, in order to solve at least one of the foregoing problems, the present application provides a packaging substrate, a MEMS microphone, an electronic device, and a packaging carrier tape. Summary of the Invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further detailed in the Detailed Description section. The Summary of the Invention section of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0006] In view of the existing problems, on the one hand, the present invention provides a packaging substrate, and the packaging substrate includes:

[0007] A first encapsulation layer, wherein at least one first hollowed-out area is provided on the first encapsulation layer;

[0008] A second encapsulation layer, wherein a mounting area is provided on a side of the second encapsulation layer facing away from the first encapsulation layer, and the mounting area is used for mounting a sound pickup chip;

[0009] A flexible circuit board is disposed between the first encapsulation layer and the second encapsulation layer, and electrical connection pins are provided on a side of the flexible circuit board facing the second encapsulation layer. The electrical connection pins are exposed through the first hollowed-out area, and the sound pickup chip is electrically connected to the electrical connection pins. Wherein, the hardness of the flexible circuit board is lower than that of the first encapsulation layer, and the hardness of the flexible circuit board is lower than that of the first encapsulation layer.

[0010] Exemplarily, the first encapsulation layer includes a rigid printed circuit board, and the second encapsulation layer includes a rigid printed circuit board.

[0011] Exemplarily, the electrical connection pins include at least two pads, the number of the first hollowed-out areas is at least two, and each of the first hollowed-out areas correspondingly exposes at least one of the pads.

[0012] Exemplarily, the at least two pads are correspondingly located outside the mounting area.

[0013] Exemplarily, at least one second hollowed-out area is provided on the second encapsulation layer, and the second hollowed-out area corresponds to the electrical connection pins of the flexible circuit board.

[0014] Exemplarily, a conductive structure penetrating the second encapsulation layer is provided in the mounting area, and the conductive structure is used for electrically connecting the sound pickup chip and a metallized structure on the flexible circuit board, and the metallized structure is electrically connected to the corresponding electrical connection pins.

[0015] Exemplarily, the metallized structure and an insulating layer are provided on a surface of the flexible circuit board facing the second encapsulation layer, and at least the metallized structure is exposed by the insulating layer.

[0016] Exemplarily, the sound pickup chip includes a MEMS chip and an audio signal processing chip, the electrical connection pins include first sub-electrical connection pins and second sub-electrical connection pins, the first sub-electrical connection pins are used for electrically connecting to the MEMS chip mounted on the second encapsulation layer, and the second sub-electrical connection pins are used for electrically connecting to the audio signal processing chip mounted on the second encapsulation layer.

[0017] In a second aspect of the present application, a MEMS microphone is further provided, and the MEMS microphone includes: the foregoing encapsulation substrate;

[0018] A sound pickup chip is disposed in the mounting area of the encapsulation substrate.

[0019] Exemplarily, the MEMS microphone includes:

[0020] A first encapsulation substrate and a second encapsulation substrate, at least one of the first encapsulation substrate and the second encapsulation substrate is configured as the foregoing encapsulation substrate, and the first encapsulation substrate and the second encapsulation substrate are joined together to form a cavity therebetween, and a first electrical connection pin is disposed on a first surface of the first encapsulation substrate facing away from the second encapsulation substrate, and a second electrical connection pin is disposed on a first surface of the second encapsulation substrate facing away from the first encapsulation substrate;

[0021] A sound pickup chip is disposed in the mounting area on a second surface of the second encapsulation substrate facing the first encapsulation substrate and within the cavity, the sound pickup chip is electrically connected to the first electrical connection pin, and the sound pickup chip is also electrically connected to the second electrical connection pin.

[0022] Exemplarily, the sound pickup chip includes a MEMS chip and an audio signal processing chip, the first electrical connection pin includes a first sub-electrical connection pin electrically connected to the MEMS chip and a second sub-electrical connection pin electrically connected to the audio signal processing chip, and the second electrical connection pin includes a first sub-electrical connection pin electrically connected to the MEMS chip and a second sub-electrical connection pin electrically connected to the audio signal processing chip.

[0023] Exemplarily, the first sub-electrical connection pin includes a pad, and the second sub-electrical connection pin includes a pad.

[0024] Exemplarily, a sound hole penetrating the second encapsulation substrate is further disposed on the second encapsulation substrate.

[0025] Exemplarily, the sound pickup chip includes a MEMS chip, the MEMS chip includes a sound cavity, and the sound hole is in communication with the sound cavity of the MEMS chip.

[0026] The third aspect of the present application provides an electronic device, including:

[0027] The foregoing MEMS microphone;

[0028] A main board, the encapsulation substrate of the microphone is mounted on the main board, and the electrical connection pins of the encapsulation substrate mounted on the main board are electrically connected to the main board.

[0029] Exemplarily, the microphone includes a first encapsulation substrate and a second encapsulation substrate. At least one of the first encapsulation substrate and the second encapsulation substrate is configured as the encapsulation substrate of the foregoing first aspect. The first encapsulation substrate and the second encapsulation substrate are joined together to form a cavity therebetween. A first electrical connection pin is provided on a first surface of the first encapsulation substrate facing away from the second encapsulation substrate, and a second electrical connection pin is provided on a first surface of the second encapsulation substrate facing away from the first encapsulation substrate. Wherein, the first surface of the second encapsulation substrate is mounted on the main board, or the first surface of the first encapsulation substrate is mounted on the main board.

[0030] Exemplarily, a sound hole penetrating through the second encapsulation substrate is further provided on the second encapsulation substrate. When the first surface of the second encapsulation substrate is mounted on the main board, a sound inlet hole communicating with the sound hole is further provided on the main board.

[0031] A fourth aspect of the present application provides a packaging carrier tape for the foregoing MEMS microphone, including:

[0032] A carrier tape substrate, the carrier tape substrate includes a plurality of positioning holes penetrating through the carrier tape substrate for placing the MEMS microphone;

[0033] A first cover tape covering a first surface of the carrier tape substrate;

[0034] A second cover tape covering a second surface of the carrier tape substrate, the second surface and the first surface are opposite to each other, and the first surface and the second surface of the MEMS microphone placed in the placement position are respectively covered by the first cover tape and the second cover tape.

[0035] The encapsulation substrate of the embodiment of the present invention includes a flexible circuit board located between a first encapsulation layer and a second encapsulation layer. Through this flexible circuit board, the function of buffering stress can be realized, so that the MEMS microphone including this encapsulation substrate has good resistance to deformation. In particular, it can relieve the deformation of the encapsulation substrate caused by the probe during the microphone test, avoid the negative impact on the MEMS chip of the MEMS microphone due to the generation of deformation, improve the stability of the MEMS microphone, avoid test errors when testing the MEMS microphone, and by making the hardness of the first encapsulation layer and the second encapsulation layer higher than that of the flexible circuit board, the hardness of the entire encapsulation substrate can meet the device requirements and play a good supporting role for the chip mounted on this encapsulation substrate.

[0036] Due to the aforementioned encapsulation substrate, the MEMS microphone according to an embodiment of the present invention has good resistance to deformation. In particular, it can alleviate the deformation of the encapsulation substrate caused by the probe during the microphone test, avoid the negative impact on the MEMS chip of the MEMS microphone due to the generation of deformation, improve the stability of the MEMS microphone, and avoid test errors during the test of the MEMS microphone.

[0037] Since the electronic device according to an embodiment of the present invention has the aforementioned MEMS microphone, it has the same advantages as the aforementioned MEMS microphone. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The following drawings of the present invention are used as a part of the present invention to understand the present invention. The embodiments of the present invention shown in the drawings and their descriptions are used to explain the principles of the present invention.

[0039] In the drawings:

[0040] Figure 1 A schematic diagram showing the deformation of the encapsulation substrate of a conventional MEMS microphone is shown;

[0041] Figure 2 A schematic diagram of a MEMS microphone according to an embodiment of the present application is shown;

[0042] Figure 3 Shows Figure 2 The exploded schematic diagram of the MEMS microphone in;

[0043] Figure 4 Shows Figure 2 The partial enlarged schematic diagram of the MEMS microphone in;

[0044] Figure 5 Shows Figure 2 The schematic diagram of one side of the second encapsulation layer of the encapsulation substrate of the MEMS microphone in;

[0045] Figure 6 Shows Figure 2 The schematic diagram of one side of the first encapsulation layer of the encapsulation substrate of the MEMS microphone in;

[0046] Figure 7 Shows Figure 2 The exploded schematic diagram of the encapsulation substrate of the MEMS microphone in;

[0047] Figure 8 A schematic diagram of the encapsulation substrate during the test of the MEMS microphone of the present application is shown;

[0048] Figure 9 A schematic diagram showing the top sound inlet and bottom sound inlet of a conventional MEMS microphone is shown;

[0049] Figure 10 Shows a schematic diagram of one side of the first packaging substrate of the MEMS microphone in another embodiment of the present application;

[0050] Figure 11 Shows a schematic diagram of one side of the second packaging substrate of the MEMS microphone in another embodiment of the present application;

[0051] Figure 12 Shows Figure 2 the exploded schematic diagram of the MEMS microphone in

[0052] Figure 13 Shows a schematic diagram of the MEMS microphone with a bottom sound inlet mode in an embodiment of the present application;

[0053] Figure 14 Shows a schematic diagram of the MEMS microphone with a top sound inlet mode in an embodiment of the present application;

[0054] Figure 15 Shows a schematic diagram of the MEMS microphone packaging carrier tape in an embodiment of the present application;

[0055] Figure 16 Shows a cross-sectional schematic diagram of the MEMS microphone packaging carrier tape in an embodiment of the present application. Detailed implementation manners

[0056] Next, the present invention will be described more completely with reference to the accompanying drawings, in which embodiments of the present invention are shown. However, the present invention can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0057] It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on", "directly adjacent to", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or portions, these elements, components, regions, layers and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or portion from another element, component, region, layer or portion. Thus, a first element, component, region, layer or portion discussed below may be denoted as a second element, component, region, layer or portion without departing from the teachings of the present invention.

[0058] Spatial relationship terms such as "under", "below", "lower", "beneath", "above", "upper", etc. are used herein for convenience in describing the relationship of one element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relationship terms are intended to include different orientations of the device in use and operation. For example, if the device in the figures is flipped, then an element or feature described as "under" or "beneath" or "below" another element or feature will be oriented "on" the other element or feature. Thus, the exemplary terms "under" and "beneath" can include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are to be interpreted accordingly.

[0059] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, specify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. As used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0060] Embodiments of the invention are described herein with reference to cross-sectional views that are schematic illustrations of ideal embodiments (and intermediate structures) of the invention. As such, variations from the shapes as shown, for example due to manufacturing techniques and / or tolerances, are to be expected. Accordingly, embodiments of the invention should not be construed as limited to the particular shapes of regions shown herein, but include shape deviations resulting, for example, from manufacturing. For example, an implantation region shown as rectangular will typically have rounded or curved features at its edges and / or an implantation concentration gradient, rather than a binary change from the implantation region to the non-implantation region. Similarly, a buried region formed by implantation can result in some implantation in the region between that buried region and the surface through which the implantation takes place. Thus, the regions shown in the figures are substantially schematic, and their shapes are not intended to show the actual shape of the regions of the device and are not intended to limit the scope of the invention.

[0061] Unless otherwise defined, 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. It will also be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.

[0062] In order to thoroughly understand the present invention, detailed structures will be presented in the following description to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other embodiments.

[0063] A MEMS microphone is a miniature microphone, so higher precision is required for its internal packaging. Especially with the rise of some miniaturized audio devices such as (True Wireless Stereo, abbreviated as TWS) earphones, the packaging size of MEMS microphones is getting smaller and smaller. Therefore, the internal packaging structure of MEMS microphones is becoming more and more compact, and the packaging difficulty is further increased. Moreover, the packaging substrate of MEMS microphones is generally very thin and easily deformed by force. Especially for small-sized packaging substrates, this deformation is more likely to be transmitted to the sensor chip, such as a MEMS chip, after being pressurized, which has a negative impact on the working state of the sensor chip. For example, as Figure 1As shown, generally, the MEMS chip is located above the packaging substrate, and the MEMS chip structure includes a diaphragm, such as a vibrating diaphragm. When the packaging substrate deforms, for example, when testing the MEMS microphone with a probe, the probe contacts the pad on the packaging substrate. Under the pressure of the probe, the entire rigid substrate will be stressed, and this stress change will be transmitted to the entire area of the packaging substrate, causing the packaging substrate to deform. This influence will be transmitted to the MEMS chip, thus affecting the state of the diaphragm in the MEMS chip, making the diaphragm loose or taut, deviating from the normal working state, and making the sensitivity of the MEMS chip abnormal. It is easy to cause errors in the test results when testing the MEMS microphone with a probe. Therefore, eliminating the influence of this external force on the MEMS chip is crucial for maintaining the normal working state of the MEMS chip.

[0064] Therefore, in view of the existence of the foregoing technical problems, the present invention proposes a packaging substrate including:

[0065] A first packaging layer provided with at least one first hollowed-out area;

[0066] A second packaging layer having a mounting area on the side facing away from the first packaging layer, and the mounting area is used for mounting a chip;

[0067] A flexible circuit board is disposed between the first packaging layer and the second packaging layer, and electrical connection pins are provided on the side of the flexible circuit board facing the second packaging layer. The first hollowed-out area exposes the electrical connection pins, and the sound pickup chip is electrically connected to the electrical connection pins. Among them, the hardness of the flexible circuit board is lower than that of the first packaging layer, and the hardness of the flexible circuit board is lower than that of the first packaging layer.

[0068] The packaging substrate of the embodiment of the present invention includes a flexible circuit board located between the first packaging layer and the second packaging layer. Through this flexible circuit board, the function of buffering stress can be realized, so that the MEMS microphone including this packaging substrate has good resistance to deformation. In particular, it can relieve the deformation of the packaging substrate caused by the probe during the microphone test, avoid the negative impact on the MEMS chip of the MEMS microphone due to the generation of deformation, improve the stability of the MEMS microphone, avoid test errors when testing the MEMS microphone, and by making the hardness of the first packaging layer and the second packaging layer higher than that of the flexible circuit board, the hardness of the entire packaging substrate can meet the device requirements and play a good supporting role for the chip mounted on this packaging substrate.

[0069] Next, the MEMS microphone, packaging substrate, electronic device, and packaging carrier tape of the present application will be explained and described with reference to the accompanying drawings. On the premise of no conflict, the technical features in each embodiment can be combined with each other.

[0070] As an example, this application provides a MEMS microphone. A microphone (abbreviated as MEMS microphone) is an acoustic-electric conversion device fabricated using micro-machining technology and is typically used in various electronic devices to complete acoustic-electric conversion.

[0071] As an example, as Figures 2 to 4 shown, the MEMS microphone 10 includes a packaging substrate 100 and a sound pickup chip disposed in the mounting area of the packaging substrate 100.

[0072] In one example, the sound pickup chip includes a MEMS chip 102 and an audio signal processing chip (such as an audio amplification chip). The audio signal processing chip may include an Application Specific Integrated Circuit (ASIC) chip. The MEMS chip 102 can be any type of MEMS chip. The MEMS chip 102 includes an internal diaphragm (also referred to as a vibrating membrane), a substrate, a sound cavity, etc. The diaphragm deforms under the change of sound pressure, thereby changing the capacitance value between the diaphragm and the substrate, generating an electrical signal, and completing the acoustic-electric conversion. The ASIC chip 101 amplifies the generated electrical signal and also provides a bias voltage for the operation of the MEMS chip 102.

[0073] In some embodiments, the MEMS microphone 10 further includes a housing 103. The housing 103 is joined to the side of the packaging substrate 100 where the sound pickup chip is disposed, thereby forming a closed cavity with the packaging substrate 100 to encapsulate the sound pickup chip in the closed cavity, so as to resist external interference and provide support and protection for the internal chip. Among them, the material of the housing 103 can be any suitable material, such as metal or other suitable materials.

[0074] In some embodiments, a sound hole may be provided on at least one of the housing 103 or the packaging substrate 100. The sound hole is a channel for an external sound signal to act on the MEMS chip 102, so that the MEMS chip 102 in the housing 103 can sense the change of sound pressure.

[0075] The following will explain and illustrate the packaging substrate 100 of this application. Among them, as Figure 5 、 Figure 6 and Figure 7As shown in the figure, the encapsulation substrate 100 includes a first encapsulation layer 110, a second encapsulation layer 120, and a flexible circuit board 130. Among them, at least one first hollowed-out area 111 is provided on the first encapsulation layer 110; a mounting area is provided on the surface of the second encapsulation layer 120 facing away from the first encapsulation layer 110, and the mounting area is used for mounting a sound pickup chip. The flexible circuit board 130 is disposed between the first encapsulation layer 110 and the second encapsulation layer 120. Electrical connection pins 131 are provided on the surface of the flexible circuit board 130 facing the second encapsulation layer 120. The first hollowed-out area 111 exposes the electrical connection pins 131, and the sound pickup chip is electrically connected to the electrical connection pins 131. Since the first hollowed-out area 111 exposes the electrical connection pins 131, it is convenient to mount the MEMS microphone 10 having the encapsulation substrate 100 on other circuit boards and form an electrical connection with the circuit board.

[0076] Furthermore, the hardness of the flexible circuit board 130 is lower than that of the first encapsulation layer 110, and the hardness of the flexible circuit board 130 is lower than that of the first encapsulation layer 110. Through the flexible circuit board 130, the function of buffering stress can be realized, so that the MEMS microphone 10 including the encapsulation substrate 100 has good resistance to deformation. In particular, it can relieve the deformation of the encapsulation substrate 100 caused by the probe during the test of the microphone 10, avoid the negative impact on the MEMS chip 102 of the MEMS microphone 10 caused by the generation of deformation, improve the stability of the MEMS microphone 10, avoid test errors during the test of the MEMS microphone 10, and by making the hardness of the first encapsulation layer 110 and the second encapsulation layer 120 higher than that of the flexible circuit board 130, the hardness of the entire encapsulation substrate 100 can meet the device requirements and play a good supporting role for the chips mounted on the encapsulation substrate 100.

[0077] Among them, the first encapsulation layer 110 may include a rigid printed circuit board (PCB board), the second encapsulation layer 120 includes a rigid printed circuit board (PCB board), and circuit structures may be provided on the first encapsulation layer 110 and the second encapsulation layer 120. For example, a grounding layer or other structures may be provided. Or, in some embodiments, the first encapsulation layer 110 and the second encapsulation layer 120 may not have circuit structures and are only PCB boards made of, for example, ceramics or other rigid materials.

[0078] The electrical connection between the sound pickup chip and the electrical connection pins can be achieved in any suitable manner. For example, the MEMS chip 102, the ASIC chip 101, and the electrical connection pins 131 are all electrically connected through the rewiring layer provided in the encapsulation substrate 100. For another example, in the mounting area of the second encapsulation layer 120, there are conductive structures such as conductive vias that penetrate the second encapsulation layer 120. The conductive structures are used to electrically connect the sound pickup chip and the metallized structure on the flexible circuit board, such as the rewiring layer or other suitable conductive structures. The metallized structure is electrically connected to the corresponding electrical connection pins, that is, the sound pickup chip is electrically connected to the metallized structure on the flexible circuit board through the conductive structure, and is electrically connected to the electrical connection pins through the metallized structure.

[0079] Optionally, the electrical connection pins 131 include at least two pads. Specifically, the number of pads can be reasonably set according to the actual device requirements. The number of the first hollow areas 111 is at least two, and each first hollow area 111 correspondingly exposes at least one pad. For example, each hollow area exposes one pad, or one hollow area exposes at least two pads.

[0080] In a specific embodiment, the electrical connection pins 131 include a first sub-electrical connection pin and a second sub-electrical connection pin. The first sub-electrical connection pin is used to electrically connect to the MEMS chip 102 mounted on the second encapsulation layer 120, and the second sub-electrical connection pin is used to electrically connect to the audio signal processing chip such as the ASIC chip 101 mounted on the second encapsulation layer 120. Optionally, the first sub-electrical connection pin includes a pad, and the second sub-electrical connection pin includes a pad.

[0081] In some embodiments, at least two pads on the flexible circuit board 130 are correspondingly located outside the mounting area of the second encapsulation layer 120, that is, when the MEMS chip 102 and the ASIC chip 101 are mounted on the mounting area of the second encapsulation layer 120, the pads are located outside the MEMS chip 102 and the ASIC chip 101. For example, they are located on both sides of the MEMS chip 102 and the ASIC chip 101. More specifically, for example, there are a total of four pads, and there are two pads on each side of the MEMS chip 102 and the ASIC chip 101.

[0082] In some embodiments, the encapsulation form of the MEMS microphone 10 can be to place the ASCI chip and the MEMS chip 102 side by side on the encapsulation substrate 100, and the three are electrically connected through wire bonding, such as gold wire bonding.

[0083] At least one second hollow area 121 is provided on the second encapsulation layer 120. The second hollow area 121 corresponds to the electrical connection pins of the flexible circuit board, that is, the second hollow area 121 exposes a partial area on the side of the electrical connection pins of the flexible circuit board that faces away from each other. Thus, when a pressure is applied to the electrical connection pins towards the second hollow area 121, due to the existence of the second hollow area 121, this compressive stress will not be transmitted to the second encapsulation layer 120, and then it will not affect the MEMS chip 102 on the second encapsulation layer 120. It is worth mentioning that the second hollow area 121 can be selectively provided, and the second encapsulation layer 120 can also not be provided with the second hollow area 121.

[0084] Further, in order to prevent electrical connection between the flexible circuit board 130 and other circuits of the second encapsulation layer 120, in some embodiments, a metallization structure and an insulating layer are provided on the surface of the flexible circuit board 130 facing the second encapsulation layer 120. The insulating layer at least exposes the metallization structure, and the insulating layer is provided before the metallization structure, so as to achieve local insulation treatment between the flexible circuit board 130 and the second encapsulation layer 120, and electrical connection pins such as pads can be led out from the side of the first encapsulation layer 110.

[0085] Due to the above structure of the encapsulation substrate 100 of the MEMS microphone 10 of the present application, as Figure 8 shown, when a test probe contacts an electrical connection pin such as a pad on the side of the second encapsulation layer 120, the pad will deform and sink inward under the probe pressure, but this sunken state will not be transmitted to the hard substrate part of the encapsulation substrate 100 (the first encapsulation layer 110 and the second encapsulation layer 120, especially the mounting area of the second encapsulation layer 120), so as to effectively buffer the deformation of the encapsulation substrate 100 caused by external pressure, improve the stability of the MEMS microphone 10, and avoid test errors.

[0086] Some microphones generally have a relatively large acoustic back cavity volume, so they generally have a relatively high signal-to-noise ratio. The signal-to-noise ratio (SNR) represents the ratio of the reference signal to the noise level signal output by the microphone. When selecting the same sensor chip and ASIC chip, due to different sound inlet methods, there will be a difference in acoustic resistance, which will further affect the sensitivity of the microphone. The noise level of the microphone is the same. The sensitivity difference caused by the structural difference will affect the product performance. Therefore, reducing the acoustic resistance and expanding the back cavity volume of the microphone are beneficial to improving the sensitivity and signal-to-noise ratio;

[0087] Common packaging forms of microphones: Top Port and Bottom Port. The difference lies in the different sizes of the space in the front volume and the back volume: The volume of the back cavity of the front-port microphone mainly depends on the internal volume of the sensor chip, and the volume of the back cavity of the back-port microphone mainly depends on the packaging size of the microphone. For example, Figure 9 As shown, the sound hole 220 of the top-port microphone is located at the top of the microphone, while the sound hole 210 of the bottom-port microphone is located at the bottom of the microphone.

[0088] Due to the small volume of the back cavity of the top-port microphone, its signal-to-noise ratio is generally low, which will have a certain impact on the use of the product. Moreover, the top-port and bottom-port of the MEMS microphone product have different acoustic structures, which will affect the backend design.

[0089] In view of the above problems, another embodiment of the present application provides a MEMS microphone. As Figures 10 to 14 shown, the MEMS microphone includes a sound pickup chip. The sound pickup chip includes a MEMS chip 330 and an audio signal processing chip (such as an audio amplification chip). The audio signal processing chip may include an Application Specific Integrated Circuit (ASIC) chip. The MEMS chip 330 may be any structure. The MEMS chip 330 includes an internal diaphragm (which can also be called a vibrating diaphragm), a substrate, a sound cavity, etc. The diaphragm deforms under the change of sound pressure, and then changes the capacitance value between the diaphragm and the substrate, generating an electrical signal to complete the conversion of sound to electricity. The ASIC chip 340 amplifies the generated electrical signal and also provides a bias voltage for the operation of the MEMS chip 330.

[0090] Furthermore, the MEMS microphone of the embodiment of the present application further includes a first packaging substrate 310 and a second packaging substrate 320, and the first packaging substrate 310 is joined to the second packaging substrate 320, and a cavity is formed between the first packaging substrate 310 and the second packaging substrate 320. This cavity can be a closed cavity. The first packaging substrate 310 and the second packaging substrate 320 can be joined in any suitable direction, such as by bonding.

[0091] In one embodiment, the second packaging substrate 320 can be configured as a packaging substrate with a cavity, and the first packaging substrate 310 can be configured as a cover structure that matches the cavity of the second packaging substrate 320 to close the cavity and form a closed cavity.

[0092] Further, in order to achieve the electrical connection of the microphone of the present application through the first packaging substrate 310 and the main board 400 (such as a PCB board) of an electronic device, a first electrical connection pin, such as a pad or a gas-type pin, is provided on the first surface of the first packaging substrate 310 facing away from the second packaging substrate 320.

[0093] Further, in order to achieve the electrical connection of the microphone of the present application through the second packaging substrate 320 and the main board 400 (such as a PCB board) of an electronic device, a second electrical connection pin, such as a pad or a gas-type pin, is provided on the first surface of the second packaging substrate 320 facing away from the first packaging substrate 310.

[0094] As Figure 10 and Figure 11 shown, the first electrical connection pin includes a first sub-electrical connection pin 311 electrically connected to the MEMS chip 330 and a second sub-electrical connection pin 312 electrically connected to the audio signal processing chip. The second electrical connection pin includes a first sub-electrical connection pin 321 electrically connected to the MEMS chip 330 and a second sub-electrical connection pin 322 electrically connected to the audio signal processing chip. For example, the first sub-electrical connection pins 311, 321 can be pads in a ring shape or other suitable shapes, while the second sub-electrical connection pins 312, 322 can be square or other suitable-shaped pads. The number of the first sub-electrical connection pins 311, 321 and the second sub-electrical connection pins 312, 322 can be reasonably set according to actual needs.

[0095] Optionally, the first electrical connection pin and the second electrical connection pin can be the same pad structure, such as a pad structure with the same shape and size, so as to ensure the universality of the corresponding welding areas on the microphone during assembly and the PCB board.

[0096] In some embodiments, a sound hole 323 penetrating the second packaging substrate 320 is further provided on the second packaging substrate 320. Alternatively, the sound hole 323 can also be provided on the first packaging substrate 310. The sound hole 323 is a channel for an external sound signal to act on the MEMS chip 330. The number of the sound holes 323 can be reasonably selected according to actual needs. In one embodiment, the sound hole 323 provided on the second packaging substrate 320 can be located within the area surrounded by the annular first sub-electrical connection pins of the second packaging substrate 320. The sound pickup chip includes the MEMS chip 330, and the MEMS chip 330 includes a sound cavity. The sound hole 323 communicates with the sound cavity of the MEMS chip 330 (i.e., the sound cavity corresponding to the diaphragm in the MEMS chip 330).

[0097] Further, the sound pickup chip is disposed on the mounting area of the second surface of the second encapsulation substrate 320 facing the first encapsulation substrate 310, and is located within the cavity enclosed by the first encapsulation substrate 310 and the second encapsulation substrate 320. The sound pickup chip is electrically connected to the first electrical connection pin, and the sound pickup chip is also electrically connected to the second electrical connection pin. Since both the first electrical connection pin and the second electrical connection pin are electrically connected to the sound pickup chip, therefore, whether the first encapsulation substrate 310 or the second encapsulation substrate 320 is mounted on the PCB board, electrical connection to the corresponding circuit on the PCB board can be achieved. The MEMS chip 330 and the ASIC chip 340 are both fixed on the encapsulation substrate by conductive adhesive

[0098] In some embodiments, a redistribution layer is provided in both the second encapsulation substrate 320 and the first encapsulation substrate 310, and there may also be electrical connection between the MEMS chip 330, the ASIC chip 340, and between the first electrical connection pin and the second electrical connection pin through the redistribution layer

[0099] Further, at least one of the first encapsulation substrate 310 and the second encapsulation substrate 320 may be configured as the encapsulation substrate in the foregoing embodiments. Alternatively, in some embodiments, the first encapsulation substrate 310 and the second encapsulation substrate 320 may also be substrates constructed in other ways, such as a PCB board

[0100] As Figure 13 shown, when the second encapsulation substrate 320 of the present application is mounted on the PCB board, the second encapsulation substrate 320 is soldered and connected to the PCB board as a bottom sound inlet MEMS microphone. When the first surface of the second encapsulation substrate 320 is mounted on the main board 400, a sound inlet hole 410 communicating with the sound hole 323 is also provided on the main board 400. At this time, the MEMS microphone is used as a microphone with a bottom sound inlet method

[0101] As Figure 14 shown, when the first encapsulation substrate 310 of the present application is mounted on the PCB board, the first encapsulation substrate 310 is soldered and connected to the PCB board as a top sound inlet MEMS microphone. The sound hole 323 is located at the top of the MEMS microphone. At this time, the MEMS microphone is used as a microphone with a top sound inlet method

[0102] Since the MEMS microphone of the present application is provided with electrical pins on opposite sides, flexible selection of top and bottom sound inlet for the same microphone can be achieved, improving the versatility of the MEMS microphone product. At the same time, the problem of small back cavity volume for top sound inlet can also be solved, improving its signal-to-noise ratio, and thus achieving better acoustic performance

[0103] Further, to facilitate the generalization of the MEMS microphone 180 in the above embodiments, the present application also provides a packaging carrier tape for the MEMS microphone 180, as Figures 15 - 16 shown, including: a carrier tape substrate 150, the carrier tape substrate includes a plurality of positioning holes 151 penetrating the carrier tape substrate for placing the MEMS microphone 180. The number of the positioning holes 151 can be reasonably set according to actual needs. The size of the positioning holes 151 is larger than the size of the pre-determined MEMS microphone 180 to be placed, so that the MEMS microphone 180 can be taken and placed from both sides of the carrier tape substrate 150.

[0104] Further, the packaging carrier tape of the present application further includes a first cover tape 160 covering the first surface of the carrier tape substrate.

[0105] Further, the packaging carrier tape of the present application has a second cover tape 170 covering the second surface of the carrier tape substrate. The second surface is opposite to the first surface. The first surface and the second surface of the MEMS microphone 180 placed in the placement position are respectively covered by the first cover tape 160 and the second cover tape 170.

[0106] The functions of the first cover tape 160 and the second cover tape 170 are to perform a sealing function. During the transportation of the MEMS microphone 180, in order to better perform the sealing function and make the MEMS microphone 180 well fixed in the positioning holes of the carrier tape substrate 150, the first cover tape 160 and the second cover tape 170 are respectively arranged on both sides at positions corresponding to the positioning holes. Moreover, the first cover tape 160 and the second cover tape 170 can also play a supporting role for the MEMS microphone 180. Optionally, the first cover tape 160 and the second cover tape 170 can both be transparent cover tapes.

[0107] Since the carrier tape substrate 150 of the packaging carrier tape of the present application has positioning holes 151 facing both sides of the carrier tape substrate 150, therefore, the direction of the MEMS microphone 180 can be flexibly changed during chip mounting, making the chip mounting operation of the MEMS microphone 180 more convenient, and especially suitable for the MEMS microphone 180 with electrical connection pins on both sides as described above.

[0108] Further, the present application also provides an electronic device, as Figure 13 and Figure 14 shown. The electronic device includes a main board 400 and the aforementioned MEMS microphone. The packaging substrate of the microphone is mounted on the main board 400, and the electrical connection pins of the packaging substrate mounted on the main board 400 are electrically connected to the main board 400.

[0109] Further, as Figure 13 and Figure 14As shown, the microphone includes a first encapsulation substrate 310 and a second encapsulation substrate 320. At least one of the first encapsulation substrate 310 and the second encapsulation substrate 320 is configured as the encapsulation substrate of the foregoing embodiment. The first encapsulation substrate 310 and the second encapsulation substrate 320 are joined together, and a cavity is formed between the first encapsulation substrate 310 and the second encapsulation substrate 320. A first electrical connection pin is provided on a first surface of the first encapsulation substrate 310 facing away from the second encapsulation substrate 320, and a second electrical connection pin is provided on a first surface of the second encapsulation substrate 320 facing away from the first encapsulation substrate 310. Wherein, the first surface of the second encapsulation substrate 320 is mounted on the main board 400, or the first surface of the first encapsulation substrate 310 is mounted on the main board 400, so as to implement a MEMS microphone with a bottom sound inlet mode or a top sound inlet mode.

[0110] Further, as Figure 14 shown, a sound hole penetrating the second encapsulation substrate 320 is further provided on the second encapsulation substrate 320. When the first surface of the second encapsulation substrate 320 is mounted on the main board 400, a sound inlet hole communicating with the sound hole is further provided on the main board 400. The sound inlet hole penetrates the main board 400. The sound inlet hole 410 and the sound hole 323 serve as channels for sound signals to enter the MEMS microphone.

[0111] The electronic device of the present application can be a mobile phone, earphone, smart speaker, smart home, tablet computer, or notebook computer, etc.

[0112] Since the electronic device of the present application includes the foregoing MEMS microphone, it has the same advantages as the foregoing MEMS microphone.

[0113] Although multiple embodiments are described herein, it should be understood that those skilled in the art can conceive of various other modifications and embodiments, and they will all fall within the spirit and scope of the concept disclosed in the present invention. More particularly, various modifications and changes can be made in the arrangement and / or components of the combination arrangement of the subject matter within the scope of the present invention disclosure, the drawings, and the appended claims. In addition to the modifications and changes in the components and / or arrangement, the use of alternative means is also an obvious choice for those skilled in the art.

Claims

1. An encapsulation substrate, characterized in that, The encapsulated substrate includes: A first encapsulation layer provided with at least one first hollowed-out area; A second encapsulation layer having a mounting area on the side facing away from the first encapsulation layer, and the mounting area is used for mounting a sound pickup chip; A flexible circuit board disposed between the first encapsulation layer and the second encapsulation layer, and electrical connection pins are provided on the side of the flexible circuit board facing the second encapsulation layer. The first hollowed-out area exposes the electrical connection pins, and the sound pickup chip is electrically connected to the electrical connection pins. Wherein, the hardness of the flexible circuit board is lower than the hardness of the first encapsulation layer, and the hardness of the flexible circuit board is lower than the hardness of the first encapsulation layer.

2. The encapsulated substrate according to claim 1, wherein The first encapsulation layer includes a rigid printed circuit board, and the second encapsulation layer includes a rigid printed circuit board.

3. The encapsulated substrate according to claim 1, wherein The electrical connection pins include at least two pads, the number of the first hollowed-out areas is at least two, and each of the first hollowed-out areas correspondingly exposes at least one of the pads.

4. The encapsulated substrate according to claim 3, characterized in that, The at least two pads are correspondingly located outside the mounting area.

5. The encapsulated substrate according to claim 1, wherein At least one second hollowed-out area is provided on the second encapsulation layer, and the second hollowed-out area corresponds to the electrical connection pins of the flexible circuit board.

6. The encapsulated substrate according to claim 1, wherein, A conductive structure penetrating the second encapsulation layer is provided in the mounting area, and the conductive structure is used for electrically connecting the sound pickup chip and a metallized structure on the flexible circuit board, and the metallized structure is electrically connected to the corresponding electrical connection pins.

7. The encapsulated substrate according to claim 6, wherein The metallized structure and an insulating layer are provided on the surface of the flexible circuit board facing the second encapsulation layer, and the insulating layer at least exposes the metallized structure.

8. The encapsulation substrate according to any one of claims 1 to 7, characterized in that, The sound pickup chip includes a MEMS chip and an audio signal processing chip. The electrical connection pins include a first sub-electrical connection pin and a second sub-electrical connection pin. The first sub-electrical connection pin is used for electrically connecting to the MEMS chip mounted on the second encapsulation layer, and the second sub-electrical connection pin is used for electrically connecting to the audio signal processing chip mounted on the second encapsulation layer.

9. A MEMS microphone, characterized in that, The MEMS microphone includes: the encapsulated substrate according to any one of claims 1-8; A sound pickup chip disposed in the mounting area of the encapsulated substrate.

10. The MEMS microphone according to claim 9, wherein, The MEMS microphone includes: A first encapsulated substrate and a second encapsulated substrate, at least one of the first encapsulated substrate and the second encapsulated substrate is configured as the encapsulated substrate according to any one of claims 1-8, and the first encapsulated substrate and the second encapsulated substrate are joined together to form a cavity therebetween. A first electrical connection pin is provided on a first surface of the first encapsulated substrate facing away from the second encapsulated substrate, and a second electrical connection pin is provided on a first surface of the second encapsulated substrate facing away from the first encapsulated substrate; A sound pickup chip disposed in a mounting area on a second surface of the second encapsulated substrate facing the first encapsulated substrate and located in the cavity. The sound pickup chip is electrically connected to the first electrical connection pin, and the sound pickup chip is also electrically connected to the second electrical connection pin.

11. The MEMS microphone according to claim 10, wherein, The sound pickup chip includes a MEMS chip and an audio signal processing chip. The first electrical connection pin includes a first sub-electrical connection pin electrically connected to the MEMS chip and a second sub-electrical connection pin electrically connected to the audio signal processing chip. The second electrical connection pin includes a first sub-electrical connection pin electrically connected to the MEMS chip and a second sub-electrical connection pin electrically connected to the audio signal processing chip.

12. The MEMS microphone according to claim 11, wherein, The first sub-electrical connection pin includes a pad, and the second sub-electrical connection pin includes a pad.

13. The MEMS microphone according to claim 10, wherein A sound hole penetrating the second encapsulation substrate is further provided on the second encapsulation substrate.

14. The MEMS microphone according to claim 13, characterized in that, The sound pickup chip includes a MEMS chip, the MEMS chip includes a sound cavity, and the sound hole is communicated with the sound cavity of the MEMS chip.

15. An electronic device, characterized in that, Comprising: The MEMS microphone according to any one of claims 9-14; A main board, the encapsulation substrate of the microphone is mounted on the main board, and the electrical connection pins of the encapsulation substrate mounted on the main board are electrically connected to the main board.

16. The electronic device according to claim 15, wherein The microphone includes a first encapsulation substrate and a second encapsulation substrate. At least one of the first encapsulation substrate and the second encapsulation substrate is configured as the encapsulation substrate according to any one of claims 1-8. The first encapsulation substrate and the second encapsulation substrate are joined together to form a cavity therebetween. A first electrical connection pin is provided on a first surface of the first encapsulation substrate facing away from the second encapsulation substrate, and a second electrical connection pin is provided on a first surface of the second encapsulation substrate facing away from the first encapsulation substrate. Wherein, the first surface of the second encapsulation substrate is mounted on the main board, or the first surface of the first encapsulation substrate is mounted on the main board.

17. The MEMS microphone according to claim 16, wherein, A sound hole penetrating the second encapsulation substrate is further provided on the second encapsulation substrate. When the first surface of the second encapsulation substrate is mounted on the main board, a sound inlet hole communicated with the sound hole is further provided on the main board.

18. A packaging carrier tape for the MEMS microphone according to one of claims 9-14, characterized in that, Comprising: A carrier tape substrate, the carrier tape substrate includes a plurality of positioning holes penetrating the carrier tape substrate for placing the MEMS microphone; A first cover tape covering the first surface of the carrier tape substrate; A second cover tape covering the second surface of the carrier tape substrate, the second surface and the first surface are opposite to each other, and the first surface and the second surface of the MEMS microphone placed in the placement position are respectively covered by the first cover tape and the second cover tape.

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