MEMS microphone

Abstract

A MEMS microphone according to the present embodiment comprises: a first substrate; a second substrate disposed on the first substrate; a MEMS structure disposed on the second substrate; and a signal processing device disposed on the second substrate and spaced apart from the MEMS structure, wherein the first substrate comprises a plurality of first front-surface pads provided on one surface thereof, each of the plurality of first front-surface pads has a via formed therein, and the signal processing device is wire-connected to the vias.

Description

MEMS microphone

[0001] The present invention relates to a MEMS microphone.

[0002] Generally, audio devices generate sound by vibrating a diaphragm using electrodes, and significant advancements are being made in the field of audio equipment alongside recent technological developments. The applications of these devices are becoming increasingly diverse, such as in portable terminals and hearing aids, and as the devices in which they are applied become slimmer, the size of the audio devices themselves is also being miniaturized.

[0003] In addition, microphones utilizing MEMS (Micro Electro Mechanical Systems), a semiconductor technology, have recently been developed and are in use. MEMS is a technology that enables the fabrication of small mechanical components on the surface of silicon wafers. These MEMS microphones can be classified into electrostatic and piezoelectric types, including general capacitor types.

[0004] Recently, mobile communication terminals such as mobile phones and smartphones, as well as electronic devices like tablet PCs and MP3 players, are becoming smaller. Consequently, the components of these electronic devices are also becoming more miniaturized. Therefore, Micro Electro Mechanical System (MEMS) technology is required to overcome the physical limitations of these components.

[0005] The technical problem that the present invention aims to solve is to provide a MEMS microphone.

[0006] To solve the above technical problem, the MEMS microphone according to the present embodiment includes a first substrate; a second substrate disposed on the first substrate; a MEMS structure disposed on the second substrate; and a signal processing element disposed on the second substrate and spaced apart from the MEMS structure, wherein the first substrate includes a plurality of first pads formed on one surface, and each of the plurality of first pads has a via formed therein, and the signal processing element is wire-connected to the via.

[0007] The vias of the plurality of first pads can be via-filled.

[0008] The plurality of first pads connected to the signal processing element can be arranged in a line along the edge of the signal processing element.

[0009] The first substrate, the second substrate, and the MEMS structure are stacked along a first direction, and the plurality of first pads connected to the signal processing element can be arranged in a line along a second direction perpendicular to the first direction.

[0010] The second substrate may have a cavity formed therein that exposes the plurality of first pads to the outside.

[0011] The first substrate may include a flexible substrate, and the second substrate may include a rigid substrate.

[0012] It includes a capacitor spaced apart from the above MEMS structure and the above signal processing element, and the capacitor may be placed on the first pad.

[0013] The capacitor comprises a first external electrode and a second external electrode disposed at both ends, and a dielectric layer disposed between the first external electrode and the second external electrode, and the first pad may include two capacitor pads spaced apart from each other, on which the first external electrode and the second external electrode of the capacitor are disposed.

[0014] The signal processing element may include a plurality of signal pads that are wire-connected to the first pad and spaced apart from each other.

[0015] The device includes a housing disposed on the second substrate, wherein the upper surface of the signal processing element is disposed to face the inner surface of the housing, and the plurality of signal pads may be disposed on the upper surface of the signal processing element.

[0016] According to the embodiments, the area of ​​the pad region of the substrate can be reduced through a wire connection structure on the via on the pad of the substrate, thereby enabling the miniaturization of the MEMS microphone and securing the placement area for other components.

[0017] In addition, the via filling structure can increase the bonding strength and reliability of the wire bonding.

[0018] FIG. 1 is a side view illustrating the structure of a MEMS microphone according to the present embodiment.

[0019] FIG. 2 is an exploded view of a substrate unit of a MEMS microphone according to the present embodiment.

[0020] FIG. 3 is a top view of a MEMS microphone according to the present embodiment.

[0021] FIGS. 4 and FIG. 5 are drawings for explaining the wire bonding structure of a capacitor of a MEMS microphone according to the present embodiment.

[0022] FIG. 6 is a diagram illustrating the connection structure between a signal processing element of a conventional MEMS microphone and a first pad of a first substrate.

[0023] FIGS. 7 and 8 are drawings for explaining the connection structure between a signal processing element of a MEMS microphone and a first pad of a first substrate according to the present embodiment.

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0025] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0026] In addition, terms used in this embodiment (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which this embodiment belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0027] Furthermore, the terms used in this embodiment are for the purpose of describing the embodiment and are not intended to limit the invention.

[0028] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0029] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the present embodiment. These terms are used merely to distinguish the components from other components and are not intended to limit the essence, order, or sequence of the components.

[0030] And, where it is stated that a component is 'connected', 'combined', or 'connected' to another component, this may include not only cases where the component is directly 'connected', 'combined', or 'connected' to the other component, but also cases where it is 'connected', 'combined', or 'connected' due to another component located between the component and the other component.

[0031] Furthermore, when described as being formed or placed "above" or "below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above" or "below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0032]

[0033] FIG. 1 is a side view illustrating the structure of a MEMS microphone according to the present embodiment, FIG. 2 is an exploded view of a substrate unit of a MEMS microphone according to the present embodiment, FIG. 3 is a top view of a MEMS microphone according to the present embodiment, FIG. 4 and FIG. 5 are drawings for explaining the wire bonding structure of a capacitor of a MEMS microphone according to the present embodiment, FIG. 6 is a drawing for explaining the connection structure between a signal processing element of a conventional MEMS microphone and a first pad of a first substrate, FIG. 7 and FIG. 8 are drawings for explaining the connection structure between a signal processing element of a MEMS microphone according to the present embodiment and a first pad of a first substrate.

[0034] Referring to FIG. 1, the MEMS microphone according to the present embodiment may include a first substrate (100), a second substrate (200), a MEMS structure (300), a housing (400), a signal processing element (500), and at least one capacitor (600).

[0035] The first substrate (100) is placed at the bottom of the MEMS microphone, has a plate shape, and can be electrically connected to the outside. A second substrate (200) is placed on the upper part of the first substrate (100) so that the first substrate (100) and the second substrate (200) can form a single substrate unit, and the substrate unit can form an internal space together with the housing (400).

[0036] The first substrate (100) is a flexible substrate and may be a Chip on Film (COF) substrate or a flexible printed circuit board (FPCB). A Chip on Film (COF) substrate is a substrate formed by forming a circuit on a base film or mounting a component such as a chip, and has a film shape, so it is a substrate with a thickness that is considerably thinner than other substrates. By using a COF substrate as the substrate for a MEMS microphone, the thickness can be reduced compared to the case where a conventional rigid substrate is used.

[0037] The first substrate (100) is a COF substrate and may include a 2-metal COF substrate. The 2-metal COF may be formed in a structure in which a metal layer is laminated on the upper and lower surfaces of a base film so as to form a circuit or mount a device on both sides of a base film.

[0038] A flexible printed circuit board (FPCB) is a flexible circuit board that is also flexible and has a thinner thickness compared to a standard PCB board, so the thickness can be reduced by using a flexible printed circuit board as a substrate for a MEMS microphone. Other types of flexible substrates may be included. For example, the first substrate (100) may be an LCP (Liquid Crystal Polymer)-based FPCB, a PI (Polyimide)-based FPCB, or a PI-based COF, and the type of the first substrate (100) is not limited to the examples described above.

[0039] A hole may be formed in the first substrate (100) at a position facing the lower part of the MEMS structure (300). The cross-sectional area of ​​the hole may be circular, but is not limited thereto. Here, the hole may be an acoustic hole.

[0040] The first substrate (100) may include a first pad (110). The first substrate (100) may have a first front pad formed on its front surface to be electrically connected to a second pad of the second substrate (200) and a first rear pad formed to be electrically connected to a rear external configuration. That is, the first pad (110) may include a first front pad and a first rear pad.

[0041] A plurality of first front pads and a first connection circuit connecting them may be formed on the front surface of the first substrate (100). A signal processing element and a capacitor may be electrically connected to the plurality of first front pads and the first connection circuit. A plurality of first rear pads and a second connection circuit may be formed on the rear surface of the first substrate (100).

[0042] The first substrate (100) may include via holes. In this case, the first substrate (100) may connect the first front pad and the first rear pad formed on both sides through a metal layer (e.g., via) formed in the via holes. Some of the first pads (110) may be exposed through the cavity (210) of the second substrate (200).

[0043]

[0044] The second substrate (200) is a substrate having a plate shape that is stacked to be placed on top of the first substrate (100). The second substrate (200) may include a rigid substrate, and may include, for example, a printed circuit board (PCB), a semiconductor substrate, or a ceramic substrate, a metal plate, etc. The second substrate (200) may be composed of a single layer or may be formed by stacking a plurality of substrates.

[0045] The second substrate (200) may include vias. In this case, the second substrate (200) may connect circuits or elements formed on both sides through a metal layer (e.g., vias) formed in the vias. Here, the vias may be micro via holes and may be configured with a size of 25 μm or less.

[0046] The second substrate (200) may include an acoustic hole. The cross-sectional area of ​​the acoustic hole may be circular, but is not limited thereto. The hole formed in the second substrate (200) may be arranged to communicate with the hole formed in the first substrate (100), and a MEMS structure (300) may be arranged on the upper part of the hole communicating with the first substrate (100) and the second substrate (200).

[0047] The second substrate (200) can be electrically connected to the first substrate (100). The second substrate (200) may include a plurality of pads for electrically connecting to the first substrate (100).

[0048] The second substrate (200) may include a second pad. The second pad may include a plurality of second front pads formed on the front surface of the second substrate (200) and a plurality of second rear pads formed on the rear surface of the second substrate (200). That is, the second pad may include a second front pad and a second rear pad. The second front pad may be electrically connected to a signal processing element (500) and a capacitor (600), and the second rear pad may be electrically connected to the first front pad of the first substrate (100). The second rear pad of the second substrate (200) may be formed to have the same or similar shape and size as the first front pad of the first substrate (100), and may be electrically connected by being stacked so that at least a portion overlaps vertically.

[0049] The second substrate (200) may include one or more cavities (210). The second substrate (200) is placed on top of the first substrate (100), and the first substrate (100) may be exposed to the top of the second substrate (200) through the cavity (210) of the second substrate (200). The first substrate (100) may be exposed to the top of the second substrate (200) by having a first pad (110), etc., placed in the space where the cavity (210) of the second substrate (200) is formed. In this case, since the upper surface of the first substrate (100) is placed on the lower surface of the second substrate (200), the first front pad, etc. formed on the upper surface of the first substrate (100) may be exposed to the top of the second substrate (200) through the cavity (210) of the second substrate (200). The first pad (110) of the first substrate (100) can be electrically connected to a signal processing element (500) and a capacitor (600) through a cavity (210) formed in the second substrate (200).

[0050] The second substrate (200) can be electrically connected to the signal processing element (500) and the capacitor (600). The second substrate (200) may include a plurality of pads, a plurality of connection circuits, and a plurality of vias for electrically connecting to the signal processing element (500) and the capacitor (600). The plurality of pads may overlap and contact the vias perpendicularly, or may contact an external substrate or element. The connection circuits may connect the second pads disposed on the same layer. The vias may be formed in vias that penetrate the base film or insulating layer.

[0051] The second substrate (200) is laminated on top of the first substrate (100) so that the first substrate (100) and the second substrate (200) can form a single substrate unit. An adhesive layer (700) is disposed between the lower part of the second substrate (200) and the upper part of the first substrate (100) to bond the first substrate (100) and the second substrate (200). The adhesive layer (700) may have a shape and size corresponding to the shape and size of the first substrate (100) or the second substrate (200) as a means of bonding the first substrate (100) and the second substrate (200). The adhesive layer (700) may be made of a conductive material, but is not limited thereto and may be made of a non-conductive material.

[0052] A PSR (Photo Solder Resist) (800) may be placed on the upper surface of the second substrate (200). The PSR (800) is an ink used to protect and form circuits on the substrate. After the circuit is formed, it is applied to the surface of the substrate and protects unnecessary parts to prevent corrosion or short circuits.

[0053]

[0054] As the first substrate (100) and the second substrate (200) form a substrate unit, the second substrate (200) not only complements the rigidity of the first substrate (100) but also simplifies the pad design structure of the second substrate (200), and since the first substrate (100) is a flexible substrate that enables fine pitch, it is implemented to have a thinner thickness and increased fine pitch realization compared to a substrate unit using a rigid substrate where the existing pad design is performed, thereby having the effect of high freedom in circuit design.

[0055] A housing (400), a MEMS structure (300), a signal processing element (500), and a capacitor (600) may be disposed on the second substrate (200). The capacitor (600) may be optionally disposed on the second substrate (200) as needed.

[0056] A housing (400) is a means for being placed on top of a second substrate (200) and forming a receiving space inside. The housing (400) may be formed in a cover shape with an open bottom surface, and the receiving space may be formed by the bottom surface of the housing (400) being joined to the top surface of the second substrate (200). The housing (400) and the second substrate (200) may be joined by solder being placed on top of the second substrate (200) and adhering to the bottom surface of the housing (400). Noise conditions such as SNR, PSR, and PSRR may be determined according to the size (Back Volume) of the receiving space formed inside the housing (400).

[0057] The housing (400) may be made of nickel silver or stainless steel (SUS). Nickel silver is a material containing 15-30% zinc and 10-20% nickel in copper, and allows for solder bonding without plating in its raw material state. Applying plating to the seating area of ​​the housing (400) can improve the solder bond adhesion. Ni+Au plating can be applied. Both electroless and electrolytic plating processes can be applied. Although stainless steel (SUS) contains Ni, the solder bond adhesion may decrease if plating is not performed. Therefore, plating can be applied. Unlike nickel silver, the plating adhesion on the surface of stainless steel may decrease when electroless plating is applied, so plating can be performed using an electrolytic plating process.

[0058] The MEMS structure (300) may be placed within a receiving space formed by a housing (400). The MEMS structure (300) may include a body (310), a backplate (330), and a diaphragm (320). The MEMS structure (300) may be placed on top of a second substrate (200), and the lower part of the MEMS structure (300) may be placed at a position adjacent to an acoustic hole (10) of the second substrate (200).

[0059] The body (310) is a means for forming a partition wall that surrounds the acoustic hole (10) formed in the second substrate (200). The body (310) can be coupled to the second substrate (200) so as to be electrically connected to the first substrate (100) through the second substrate (200). Additionally, an acoustic hole (360) communicating with the acoustic hole (10) can be formed in the body (310). The body (310) can be electrically connected to the second substrate (200).

[0060] An acoustic hole (360) may be formed in the body (310). When the body (310) is coupled to the second substrate (200), the acoustic hole (10) formed in the first substrate (100) and the second substrate (200) and the acoustic hole (360) of the body (310) may be arranged to communicate with each other, and thus, sound from the outside may be designed to flow in through the acoustic hole (10).

[0061] The backplate (330) and the diaphragm (320) can be placed in the acoustic hole (10) formed in the body (310). The diaphragm (320) can vibrate due to the sound pressure of the sound when sound is introduced from the outside through the acoustic hole (10), and the backplate (330) can sense the acoustic signal by measuring the capacitance according to the vibration of the diaphragm (320). Although the backplate is shown as being located above the diaphragm (320) in the drawing, the diaphragm (320) may also be located above the backplate.

[0062] One or more body pads for electrical connection may be formed on the upper surface of the body (310). The body pads may be electrically connected to the backplate (330) and the diaphragm (320), and may be electrically connected to the signal processing element (500), which will be described later, via a wire. However, the connection method is merely an example, and as needed, the body pads may be placed in a form directly mounted on the pads of the second substrate (200) and electrically connected to the signal processing element (500) through a connection circuit. As the shape and material of the body pads are known technologies for electrical connection, a description thereof is omitted.

[0063] The signal processing element (500) is electrically connected to the MEMS structure (300) and can process electrical signals sensed from the MEMS structure (300). The MEMS structure (300) and the signal processing element (500) can be electrically connected through a body pad. For example, the MEMS structure (300) and the signal processing element (500) can be connected by a wire through wire bonding. As another example, the MEMS structure (300) and the signal processing element (500) can be electrically connected through a connection circuit of the second substrate (200) while mounted on the second substrate (200) in a flip-chip form. When the MEMS structure (300) and the signal processing element (500) are wire-bonded, a signal pad (510) may be placed on the signal processing element (500) to be connected to the body pad of the MEMS structure (300) through wire bonding.

[0064] The signal processing element (500) can amplify a signal sensed from the MEMS structure (300). Here, the signal processing element (500) may include an Application-Specific Integrated Circuit (ASIC), but is not limited thereto. The signal processing element (500) may be formed as a single module or may be formed in the form of a chip. The signal processing element (500) may include an ASIC and an En-cap that coats the ASIC.

[0065] A signal processing element (500) may be placed on a second substrate (200). The signal processing element (500) may be electrically connected to a first substrate (100) through the second substrate (200). The signal processing element (500) may be placed on the second substrate (200) spaced apart from the MEMS structure (300). The signal processing element (500) may be placed in a receiving space formed inside a housing (400) spaced apart from the MEMS structure (300) and may receive a signal from the MEMS structure (300). Since signal transmission between the MEMS structure (300) and the signal processing element (500) takes place in the receiving space formed by the housing (400), external interference is reduced, and thereby noise can be reduced.

[0066] The signal processing element (500) can be electrically connected to the MEMS structure (300) and the first substrate (100). The signal processing element (500) can be electrically connected to the MEMS structure (300). The signal processing element (500) can be electrically connected to a body pad formed on the body (310) of the MEMS structure (300) by having a signal pad (510) disposed on its upper surface. The signal pad (510) of the signal processing element (500) and the body pad of the MEMS structure (300) can be electrically connected through wire bonding, thereby allowing the signal processing element (500) and the MEMS structure (300) to be electrically connected.

[0067] The signal processing element (500) can be electrically connected to the first substrate (100). The signal processing element (500) can be electrically connected to the first pad (110) of the first substrate (100) through wire bonding. The signal processed by the signal processing element (500) can be transmitted to an external location requiring the signal through the pad formed on the first substrate (100).

[0068] According to a modified example, the signal processing element (500) can be electrically connected to the first substrate (100) by being electrically connected to the second substrate (200). The signal processing element (500) can be electrically connected to the second substrate (200) through wire bonding or electrically connected by being mounted on the second substrate (200) in the form of a flip chip. Since a plurality of pads are arranged on the second substrate (200), the signal processing element (500) can be electrically connected to the pads of the second substrate (200) through wire bonding or electrically connected by being mounted on the pads of the second substrate (200) in the form of a flip chip, and can be electrically connected to the first substrate (100) through the pads of the second substrate (200). The signal processed by the signal processing element (500) can be transmitted to an external location requiring the signal through one or more of the pads, connection circuits, and vias formed on the second substrate (200) and through the pads formed on the first substrate (100).

[0069]

[0070] Referring to FIG. 6, the first pad (110) of the existing first substrate (100) includes a pad connected to the signal pad (510) of the signal processing element (500) and a pad (115) having a via (116) formed therein. The pad connected to the signal pad (510) of the signal processing element (500) and the pad (115) having a via (121) formed therein are formed at different locations and are electrically connected. In this structure, there is a problem that the area for forming each pad on the first substrate (100) increases.

[0071] Referring to FIG. 7, the MEMS microphone according to the present embodiment applies a pad-on-via structure in which vias are integrated within the pads to maximize the use of substrate space as it is miniaturized. By placing vias directly on the pads, a direct path for heat dissipation is formed, which improves thermal conductivity, shortens the connection path, reduces signal distortion and electromagnetic interference, and can improve performance by increasing the signal speed to high speed.

[0072] In addition, there is a problem in that the success rate of the wire bonding process decreases because vibration of the substrate occurs during the wire bonding process on the pad of the first substrate (100) formed as a thin flexible substrate. The MEMS microphone according to the present embodiment can reinforce the bonding strength during wire bonding and increase the success rate of the wire bonding process through a via filling structure in which the inside of the via is filled.

[0073] In the MEMS microphone according to the present embodiment, the first substrate (100) includes a plurality of first pads (120) formed on one surface, and each of the plurality of first pads (120) may have a via (121) formed therein. The interiors of the first pads (120) and vias (121) may be plated. The interiors of the first pads (120) and vias (121) may be plated with copper (Cu) or gold (Au).

[0074] The signal processing element (500) can be connected to the via (121) by a wire (20). The signal processing element (500) can be connected to the first pad (120) where the via (121) is formed by a wire (20). The signal pad (510) of the signal processing element (500) can be connected to the via (121) by a wire (20). The signal pad (510) of the signal processing element (500) can be connected to the first pad (120) where the via (121) is formed by a wire (20).

[0075] The wire (20), the first pad (120), and the via (121) may be arranged to overlap in a first direction (z-axis direction). The wire bonding process may be performed by melting the end of the wire to form a ball and then thermally or ultrasonically pressing the ball onto a pad on a substrate, as is previously known.

[0076] The via (121) can be via filled. Via filling refers to a process of filling a via, which is a copper-plated hole, with a conductive material (e.g., conductive epoxy, etc.) or a non-conductive material (e.g., resin or solder mask, etc.). Via filling can prevent impurities from entering the via and can reinforce the rigidity of the substrate. In addition, it can reinforce the bonding strength during the bonding of the wire (20) and increase the success rate of the wire bonding process.

[0077] A plurality of first pads (120) formed on one surface of the first substrate (100) may be spaced apart from each other. A plurality of first pads (120) connected to the signal processing element (500) may be arranged in a line along the edge of the signal processing element (500). The signal pad (510) of the signal processing element (500) may be arranged in a line along the edge closest to the plurality of first pads (120). A plurality of first pads (120) connected to the signal processing element (500) may be arranged in a line along a second direction (x-axis direction) perpendicular to a first direction (z-axis direction), which is the stacking direction of the substrate unit.

[0078] By doing so, the gap between the signal pad (510) of the signal processing element (500) and the plurality of first pads (120) can be minimized to increase the reliability of the wire (20) connection and reduce the length of the plated wire (20), thereby reducing manufacturing costs. In addition, the area where the plurality of first pads (120) are formed on the first substrate (100) can be minimized.

[0079] Referring to FIG. 8, the area of ​​one of the plurality of first pads (120) connected to the signal pad (510) of the signal processing element (500) may be approximately 90 µm x 90 µm, and the diameter of the ball for bonding the wire (20) may be approximately 65 µm. The area of ​​one signal pad (510) of the signal processing element (500) may be approximately 40 µm x 40 µm, and the diameter of the ball for bonding the wire (20) on the signal pad (510) may be approximately 40 µm.

[0080] "The size of the area (q) where a plurality of first pads (120) are formed / the size of the area where the signal pad (510) of the signal processing element (500) is formed" may satisfy 3 or more and 7 or less, and preferably 5 or more and 6 or less. For example, "the size of the area (q) where a plurality of first pads (120) are formed / the size of the area where the signal pad (510) of the signal processing element (500) is formed" may satisfy approximately 5.0625.

[0081] In the first substrate (100) of the MEMS microphone according to the present embodiment, the size of the first region (q) where the first pad (120) connected to the signal processing element (500) is formed can be formed smaller than the size of the second region (p) where the first pad (110) connected to the signal processing element (500) is formed in the first substrate (100) of the conventional MEMS microphone. For example, the size of the first region (q) can be reduced to about 55% of the size of the second region (p).

[0082] Through this, the cavity (210) area of ​​the second substrate (200) can be reduced, the attachment area of ​​the adhesive layer (700) can be expanded, and the adhesion strength between the first substrate (100) and the second substrate (200) can be increased, thereby increasing the rigidity of the substrate unit. In addition, the area of ​​the copper (Cu) pattern, which is a circuit pattern formed on the first substrate (100), can be reduced, thereby securing an additional area for the placement of a capacitor (600) or a pattern inductor within the first substrate (100) or the second substrate (200).

[0083]

[0084] A capacitor (600) may be optionally placed on the upper part of the second substrate (200) as needed. When the capacitor (600) is placed, the performance of PSRR, which is RF-related noise, and the performance of PSR, which is power-related noise, may be improved. That is, through the capacitor (600), noise-related performance such as SNR, PSRR, and PSR can be improved. The capacitor (600) may be electrically connected to the signal processing element (500). As a result, the capacitor (600) can remove noise during the process of processing signals in the signal processing element (500).

[0085] The capacitor (600) may be a Multi Layer Ceramic Capacitor (MLCC). The capacitor (600) may include a first external electrode and a second external electrode disposed at both ends, a plurality of internal electrodes disposed between the first external electrode and the second external electrode, and a dielectric layer. The first external electrode and the second external electrode can electrically connect the internal electrode and the external circuit. The dielectric layer is a material that serves as an electrical storage for the capacitor, and the capacitance increases as the number of dielectric layers increases. The dielectric layer may be disposed between the first external electrode and the second external electrode and between the plurality of internal electrodes. The plurality of internal electrodes are electrodes inserted between the dielectric layers.

[0086] The area where the capacitor (600) is placed may satisfy an area of ​​3% or more and 5% or less relative to the area of ​​the first substrate (100) or the second substrate (200). If this is satisfied, a capacitor that stably supplies high-capacity power to a miniaturized MEMS microphone can be appropriately placed. If the lower limit of the above condition is less than the upper limit, there is a problem in that the power capacity required for the MEMS microphone is not satisfied. If the upper limit of the above condition is exceeded, there is a problem in that there is insufficient space for placing other components included in the MEMS microphone.

[0087] The capacitor (600) is positioned on the upper part of the second substrate (200) and can be electrically connected to the signal processing element (500) and can be electrically connected to the first substrate (100) through the second substrate (200). The capacitor (600) can be electrically connected to the signal processing element (500) and the first substrate (100) via wires. The capacitor (600) can be electrically connected to the signal pad (510) of the signal processing element (500) via wire bonding and can be electrically connected to the pad of the second substrate (200) via wire bonding.

[0088] According to a modified example, the capacitor (600) can be electrically connected to the first substrate (100) by being mounted on the second substrate (200) or the signal processing element (500) in a flip-chip form, as well as by bonding via wires. For example, the capacitor (600) can be mounted on a second pad formed on the upper part of the second substrate (200). The capacitor (600) can be mounted on a second front pad formed on the front surface of the second substrate (200). As the fine-pitch circuit implementation of the second substrate (200) becomes possible, the effect of securing mounting space for the capacitor is achieved.

[0089] FIG. 4 illustrates a capacitor (600) being bonded to a second substrate (200) by an adhesive member (900) and wired to a second pad formed on the second substrate (200). In the first direction (z-axis direction), the length (a) of the capacitor (600) is approximately 300 µm and can satisfy an error range of ±5% or less. The thickness (b) of the adhesive member (900) for fixing the capacitor (600) on the second substrate (200) is approximately 50 µm or less in the first direction (z-axis direction) and can satisfy an error range of ±5% or less. The capacitor (600) can be wired to a pad formed on the second substrate (200). In the first direction (z-axis direction), the length (c) of the wire (20) from the second substrate (200) is approximately 500 µm or less and can satisfy an error range of ±5% or less. In the first direction (z-axis direction), the length (d) of the wire (20) from the capacitor (600) is about 150 µm or less, and can satisfy an error range of ±5% or less.

[0090] FIG. 5 illustrates a capacitor (600) being placed on a second substrate (200) and connected to a first pad (110) formed on a first substrate (100) by a wire (20). In the first direction (z-axis direction), the length (e) between the second substrate (200) and the capacitor (600) is approximately 448 μm, and can satisfy an error range of ±5% or less. In the second direction (x-axis direction) perpendicular to the first direction (z-axis direction), the length (f) of the wire (20) connecting the first pad (110) and the capacitor (600) is approximately 407 μm, and can satisfy an error range of ±5% or less. When viewed from the side of the capacitor (600), the length (g) of the wire (20) connecting the first pad (110) and the capacitor (600) in the third direction (y-axis direction) perpendicular to the first direction (z-axis direction) and the second direction (x-axis direction) is approximately 225 μm, and can satisfy an error range of ±5% or less. That is, when the capacitor (600) is bonded to the first substrate (100) or the second substrate (200) through a wire bonding process, an additional area due to wire bonding is required in addition to the size of the capacitor (600).

[0091] According to another embodiment, the capacitor (600) may be placed on the upper surface of the first substrate (100). The capacitor (600) may be placed on the first pad (110) of the first substrate (100) which is exposed through the cavity (210) of the second substrate (200). The capacitor (600) may be soldered to the first pad (110) of the first substrate (100). The first substrate (100) may include a region (220) where the capacitor (600) is placed. The capacitor (600) may be placed on two capacitor pads that are included in the first pad (110) of the first substrate (100) and spaced apart from each other. The first external electrode and the second external electrode of the capacitor (600) may be placed on the capacitor pads of the first substrate (100).

[0092]

[0093] Those skilled in the art related to the embodiments described above will understand that they may be implemented in modified forms without departing from the essential characteristics of the description. Therefore, the disclosed methods should be considered in an illustrative rather than a restrictive sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalence should be interpreted as being included in the invention.

Claims

1. First substrate; A second substrate disposed on the first substrate; A MEMS structure disposed on the second substrate; and It includes a signal processing element spaced apart from the MEMS structure and disposed on the second substrate, and The first substrate includes a plurality of first pads formed on one surface, and Each of the above plurality of first pads has a via formed therein, and The above signal processing element is a MEMS microphone wired to the above via.

2. In Paragraph 1, The vias of the plurality of first pads are via-filled MEMS microphones.

3. In Paragraph 1, The plurality of first pads connected to the signal processing element are MEMS microphones arranged in a row along the edge of the signal processing element.

4. In Paragraph 1, The first substrate, the second substrate, and the MEMS structure are stacked along a first direction, and The plurality of first pads connected to the signal processing element are MEMS microphones arranged in a line along a second direction perpendicular to the first direction.

5. In Paragraph 1, The above-mentioned second substrate is a MEMS microphone having a cavity formed therein that exposes the plurality of first pads to the outside.

6. In Paragraph 1, The first substrate above includes a flexible substrate, and The above second substrate is a MEMS microphone comprising a rigid substrate.

7. In Paragraph 1, It includes a capacitor spaced apart from the above MEMS structure and the above signal processing element, and The above capacitor is a MEMS microphone placed on the first pad.

8. In Paragraph 7, The capacitor comprises a first external electrode and a second external electrode disposed at both ends, and a dielectric layer disposed between the first external electrode and the second external electrode. The first pad above is a MEMS microphone comprising two capacitor pads spaced apart from each other, wherein the first external electrode and the second external electrode of the capacitor are disposed thereon.

9. In Paragraph 1, A MEMS microphone comprising a plurality of signal pads wired to the first pad of the signal processing element and spaced apart from each other.

10. In Paragraph 9, It includes a housing disposed on the second substrate, and The upper surface of the signal processing element is positioned to face the inner surface of the housing, and The plurality of signal pads are MEMS microphones disposed on the upper surface of the signal processing element.

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