MEMS microphone

Abstract

A MEMS microphone according to one embodiment of the present invention includes a first substrate, a second substrate stacked on the first substrate, a MEMS structure disposed on the second substrate, and a capacitor spaced apart from the MEMS structure and disposed on the second substrate, in which the second substrate includes at least one hole, and the capacitor is electrically connected with the first substrate through a wire passing through the hole of the second substrate.

Description

Technical Field

[0001] This invention relates to a MEMS microphone, and more specifically, to a MEMS microphone using COF. Background Technology

[0002] Typically, audio devices use electrodes to vibrate a diaphragm to produce sound. With recent technological advancements, the field of audio devices has made significant progress. The applications of these audio devices (such as portable terminals and hearing aids) have become increasingly diverse, and the size of the audio devices themselves is also shrinking as the devices themselves become thinner.

[0003] In addition, miniature phones utilizing microelectromechanical systems (MEMS) as a semiconductor technology have recently been developed and are in use. MEMS is a technology that enables the fabrication of small mechanical parts on the surface of a silicon wafer. These MEMS microphones can be categorized as electrostatic or piezoelectric, and also include general capacitor types.

[0004] Recently, mobile communication terminals such as mobile phones and smartphones, as well as electronic devices such as tablet PCs and MP3 players, have become increasingly miniaturized. Consequently, the components of electronic devices have also become smaller. Therefore, there is a need for microelectromechanical systems (MEMS) technology that can overcome the physical limitations of these components. Summary of the Invention

[0005] Technical issues

[0006] The technical problem to be solved by the present invention is to provide a MEMS microphone using COF.

[0007] Technical solution

[0008] To address the aforementioned technical problems, a MEMS microphone according to an embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on the first substrate; a MEMS structure disposed on the second substrate; and a capacitor, the capacitor being spaced apart from the MEMS structure and disposed on the second substrate, wherein the second substrate includes one or more holes, and wherein the capacitor is electrically connected to the first substrate through a wire passing through the hole in the second substrate.

[0009] Additionally, the holes in the second substrate may include: a first hole through which a line connecting the capacitor to the first substrate passes; and a second hole corresponding to the lower part of the MEMS structure.

[0010] Additionally, the holes in the second substrate may include: a first hole through which a line connecting the capacitor and the first substrate passes; and a second hole corresponding to the lower part of the MEMS structure.

[0011] In addition, the holes in the second substrate can be formed at a predetermined distance or more from the outer periphery of the second substrate.

[0012] Additionally, a conductive adhesive layer may be included between the first substrate and the second substrate, and the conductive adhesive layer may include holes that overlap with holes in the second substrate.

[0013] In addition, the area of ​​the holes in the conductive adhesive layer can be larger than the area of ​​the holes in the second substrate.

[0014] Additionally, the first substrate may include a connection pad disposed at a position corresponding to the lower part of the hole in the second substrate.

[0015] In addition, the MEMS microphone includes an ASIC module disposed on the second substrate and spaced apart from the MEMS structure, and the ASIC module can be electrically connected to the first substrate through a wire passing through a hole in the second substrate.

[0016] In addition, the ASIC module can be electrically connected to the MEMS structure and capacitors via wires, respectively.

[0017] In addition, the first substrate can be a flexible substrate, and the second substrate can be a rigid substrate.

[0018] In addition, the first substrate and the second substrate can be joined by thermoforming.

[0019] To solve the above-mentioned technical problems, a MEMS microphone according to a second embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a MEMS structure and a signal processing element, the MEMS structure and the signal processing element being disposed on the second substrate; a first capacitor, the first capacitor being stacked on the first substrate, the second substrate not being stacked on the first substrate; and a second capacitor, the second capacitor being stacked below the signal processing element.

[0020] In addition, the first electrode of the second capacitor is electrically connected to the first substrate, and the second electrode of the second capacitor can be electrically connected to the second substrate.

[0021] In addition, the first electrode of the second capacitor can be disposed at the lower part of the second capacitor and bonded to the first substrate by welding.

[0022] Additionally, the upper part of the second capacitor may include: a conductive adhesive layer electrically connecting the second capacitor and the second substrate; and a non-conductive adhesive layer stacked between the conductive adhesive layer and the signal processing element.

[0023] In addition, the second substrate may include an etched area in the area where the second capacitor is disposed.

[0024] In addition, the signal processing element can be connected to the MEMS structure and the first substrate respectively via wires.

[0025] To address the aforementioned technical problems, a MEMS microphone according to another embodiment of the second embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a housing covering the second substrate; a MEMS structure disposed on the second substrate; a first capacitor spaced apart from the MEMS structure and disposed on the second substrate; and a second capacitor stacked below the first capacitor.

[0026] In addition, the first electrode of the first capacitor is located on the second capacitor, and the second electrode of the first capacitor may be located on the second substrate.

[0027] In addition, the first electrode of the second capacitor is electrically connected to the first electrode of the first capacitor, and the second electrode of the second capacitor can be electrically connected to the first substrate.

[0028] In addition, the second substrate may include an etched area in the area where the second capacitor is disposed.

[0029] Additionally, the MEMS microphone includes a metal portion stacked on the lower part of a first capacitor, wherein a first electrode of the first capacitor is located on a second capacitor, and wherein a second electrode of the first capacitor may be located on the metal portion.

[0030] In addition, the first electrode of the first capacitor can be connected to the first substrate via a wire.

[0031] In addition, the second substrate includes a half-etched region having a metal portion and a second capacitor, wherein the thickness of the half-etched region can be thinner than the thickness of the other regions.

[0032] Additionally, the MEMS microphone includes a third capacitor stacked on the lower part of the first capacitor, wherein the first electrode of the first capacitor is located on the second capacitor, and wherein the second electrode of the first capacitor may be located on the third capacitor.

[0033] In addition, the second electrode of the first capacitor can be electrically connected to the first electrode of the third capacitor.

[0034] In addition, the first electrode of the first capacitor can be connected to the first substrate via a wire.

[0035] In addition, the second substrate includes a half-etched region in which a second capacitor and a third capacitor are disposed, and the thickness of the half-etched region can be thinner than the thickness of the other regions.

[0036] To address the aforementioned technical problems, a MEMS microphone according to yet another embodiment of the second embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a housing covering the second substrate; a MEMS structure disposed on the second substrate; a first capacitor disposed on the first substrate in which the second substrate is not stacked; a second capacitor stacked below the first electrode of the first capacitor; and a fourth capacitor stacked below the second electrode of the first capacitor.

[0037] In addition, the first electrode of the second capacitor is electrically connected to the first electrode of the first capacitor; the second electrode of the second capacitor is electrically connected to the first substrate; the first electrode of the fourth capacitor is electrically connected to the first substrate; and the second electrode of the fourth capacitor can be electrically connected to the second electrode of the first capacitor.

[0038] In addition, the first electrode of the first capacitor can be connected to the first substrate via a wire.

[0039] To address the aforementioned technical problems, a MEMS microphone according to a third embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a MEMS structure and signal processing element disposed on the second substrate; and a capacitor element, the capacitor element being stacked on the first substrate in which the second substrate is not stacked, wherein the capacitor element includes a capacitor and an interlayer stacked on the lower portion of the capacitor.

[0040] Additionally, the interposer includes an FR4 printed circuit board, on which capacitors can be surface-mounted.

[0041] Additionally, the interlayer includes a metal plate, on which capacitors can be mounted.

[0042] In addition, the metal plate includes a first metal plate and a second metal plate, wherein the first metal plate and the second metal plate can form a bridging structure that is respectively connected to the two electrodes of the capacitor.

[0043] In addition, the interposer may include any one of FR4 printed circuit board, metal plate, lead frame, ceramic printed circuit board and metal printed circuit board.

[0044] In addition, capacitor elements can be soldered onto the first substrate.

[0045] In addition, the capacitor element is positioned separately from the signal processing element, but the capacitor element can be electrically connected to the signal processing element.

[0046] In addition, signal processing components may include ASIC modules.

[0047] In addition, the first substrate can be a flexible substrate, and the second substrate can be a rigid substrate.

[0048] In addition, the first substrate and the second substrate can be joined by thermoforming.

[0049] To address the aforementioned technical problems, a MEMS microphone according to a fourth embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a conductive adhesive layer, the conductive adhesive layer being stacked between the first substrate and the second substrate; an upper adhesive layer, the upper adhesive layer being stacked on the second substrate; and a MEMS structure and a signal processing element, the MEMS structure and the signal processing element being disposed on the upper adhesive layer, wherein the MEMS structure is directly bonded to the upper adhesive layer, and wherein the upper adhesive layer includes a coverlay or a photoresist layer.

[0050] To address the aforementioned technical problems, a MEMS microphone according to another embodiment of the fourth embodiment of the present invention includes: a first substrate; a first photoresist layer, the first photoresist layer being stacked on at least one region of the first substrate; a second photoresist layer, the second photoresist layer being stacked on at least one region of the lower portion of the first substrate; and a MEMS structure and signal processing elements, the MEMS structure and signal processing elements being disposed on the first photoresist layer, wherein the first substrate is directly bonded to the first photoresist layer and the second photoresist layer.

[0051] To address the aforementioned technical problems, a MEMS microphone according to another embodiment of the fourth embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a conductive adhesive layer, the conductive adhesive layer being stacked between the first substrate and the second substrate; a MEMS structure and a signal processing element, the MEMS structure and the signal processing element being disposed on the second substrate; and a cover, the cover covering the second substrate, wherein the second substrate includes a base facing the first substrate and a side plate extending upward from the outer periphery of the base, and wherein the cover is disposed at an end of the side plate of the second substrate.

[0052] In addition, the first substrate and the cover can be made of the same material.

[0053] In addition, the second substrate and the cover can be joined by welding.

[0054] Alternatively, the first substrate may include a 2METAL COF substrate.

[0055] In addition, the first substrate is a flexible substrate, while the second substrate can be a rigid substrate.

[0056] In addition, the second substrate may contain any one of nickel silver, SUS, ceramic and FR4.

[0057] Additionally, the MEMS microphone may include a capacitor disposed in the second substrate and spaced apart from the signal processing elements.

[0058] In addition, signal processing components may include ASIC modules.

[0059] To solve the above-mentioned technical problems, a MEMS microphone according to a fifth embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a shield can being joined to the second substrate; and a MEMS structure and signal processing elements disposed on the second substrate within the internal space of the shield can, wherein the shield can is made of the same material as the second substrate.

[0060] In addition, the second substrate and shield can be made of SUS or nickel silver.

[0061] In addition, the second substrate includes a mounting portion on which the shield is disposed in the area where it engages with the shield, wherein the thickness of the mounting portion of the second substrate may be thinner than the thickness of other areas of the second substrate other than the mounting portion.

[0062] Additionally, the shielding cover may include: a top plate; a side plate extending from the outer periphery of the top plate to the lower part of the top plate; and a lead wire portion extending outward from the end of the side plate.

[0063] Additionally, the shielding cover may include: a top plate; a side plate extending from the outer periphery of the top plate to the lower part of the top plate; and a plurality of protrusions extending from the ends of the side plates to the lower part of the side plates and spaced apart from each other.

[0064] In addition, the second substrate may not be stacked on the area corresponding to the protrusion of the shield.

[0065] Additionally, a second substrate can be etched in the area corresponding to the protrusion of the shield, so that the end of the protrusion of the shield can be joined to the first substrate.

[0066] In addition, the side surface of the protrusion of the end of the side plate of the shielding cover and the end of the protrusion can be joined to the second substrate.

[0067] In addition, the epoxy resin or silicone resin filling the steps of the areas where the shielding cover can be joined with the first substrate and the second substrate can be bonded together with the shielding cover.

[0068] In addition, the upper plate of the shield has a square shape, the side plates of the shield include a first side plate to a fourth side plate extending from the upper plate, and a plurality of protrusions can extend from the end of the side plate to the lower part along the shape of the edge connecting two adjacent side plates in the first side plate to the fourth side plate.

[0069] To solve the above-mentioned technical problems, a MEMS microphone according to a fifth embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a housing, the housing being joined to the second substrate; and a MEMS structure and a signal processing element, the MEMS structure and the signal processing element being disposed on the second substrate in the internal space of the housing, wherein the second substrate includes an etched region, the MEMS structure or the signal processing element being disposed in the etched region, and wherein the thickness of the etched region of the second substrate is thinner than the thickness of other regions of the second substrate other than the etched region.

[0070] In addition, when bonding the MEMS structure to the second substrate, epoxy resin or silicon can be coated inside the etched area.

[0071] Additionally, in the etching region of the second substrate, the surface facing the first substrate can be etched to form a cavity.

[0072] In addition, a wire electrically connected to the first substrate can be provided in the chamber.

[0073] Additionally, the MEMS microphone may include a capacitor disposed in an etched area of ​​the second substrate and spaced apart from the signal processing elements within the housing.

[0074] In addition, signal processing components may include ASIC modules.

[0075] In addition, the first substrate is a flexible substrate, while the second substrate can be a rigid substrate.

[0076] In addition, the first substrate and the second substrate can be joined by thermoforming.

[0077] To address the aforementioned technical challenges, a MEMS microphone according to another embodiment of the sixth embodiment of the present invention includes: a first substrate; a second substrate, the second substrate being stacked on at least one region of the first substrate; a housing, the housing being joined to the second substrate; and a MEMS structure and signal processing element, the MEMS structure and signal processing element being disposed on the second substrate within the internal space of the housing, wherein the second substrate is not stacked on the region where the MEMS structure or signal processing element is disposed.

[0078] In addition, the second substrate is not stacked in the region where one of the MEMS structure and signal processing element is disposed; the region where the other is disposed includes the etched region; and the thickness of the etched region of the second substrate may be thinner than the thickness of other regions of the second substrate other than the etched region.

[0079] Beneficial effects

[0080] According to embodiments of the present invention, the process can be simplified and the time can be shortened. Furthermore, the etched area of ​​the metal plate hole can be reduced, thus reducing process control points, increasing design freedom for hole shape and size reduction, increasing capacitor capacitance, and increasing the adhesion area of ​​the conductive adhesive layer, thereby preventing peeling and increasing reliability.

[0081] According to embodiments of the present invention, multiple capacitors can be installed, thus allowing for the installation of capacitors for removing power supply noise and radio frequency (RF) noise. Furthermore, capacitors can be installed separately for removing power supply noise from DVdd and AVdd.

[0082] According to embodiments of the present invention, audible noise caused by capacitor mounting can be eliminated. The process can be simplified by manufacturing the capacitor as a separate element capable of eliminating audible noise.

[0083] According to embodiments of the present invention, by using a capping layer or PSR, MEMS stress can be improved and solder delamination can be prevented. Additionally, the thickness of the substrate or cap can be reduced, ensuring SNR performance and lowering production costs.

[0084] According to embodiments of the present invention, the bonding reliability can be improved by using a shield made of the same material as the metal plate, or a leaded, non-leaded, or castle-type shield.

[0085] According to embodiments of the invention, by applying partial or full etching to the metal plate differently, the cavity and flip chip bonding can be ensured; by forming a cavity between the metal plate and the COF, the wiring freedom of the 2-Metal COF can be ensured; the degrees of freedom are extended to reflect the design, such as minimizing line losses, and parasitic impedance becomes possible; thereby, SNR performance can be improved by minimizing noise levels. Attached Figure Description

[0086] Figure 1 A MEMS microphone according to an embodiment of the present invention is shown.

[0087] Figures 2 to 13 This is a diagram illustrating a MEMS microphone according to a first embodiment of the present invention.

[0088] Figure 14 A MEMS microphone according to a second embodiment of the present invention is shown.

[0089] Figures 15 to 24 This is a diagram illustrating a MEMS microphone according to a second embodiment of the present invention.

[0090] Figure 25 A MEMS microphone according to a third embodiment of the present invention is shown.

[0091] Figure 26 This is a diagram illustrating a MEMS microphone according to a third embodiment of the present invention.

[0092] Figure 27 A MEMS microphone according to a fourth embodiment of the present invention is shown.

[0093] Figures 28 to 37 This is a diagram illustrating a MEMS microphone according to a fourth embodiment of the present invention.

[0094] Figure 38 A MEMS microphone according to a fifth embodiment of the present invention is shown.

[0095] Figures 39 to 46 This is a diagram illustrating a MEMS microphone according to a fifth embodiment of the present invention.

[0096] Figure 47 A MEMS microphone according to a sixth embodiment of the present invention is shown.

[0097] Figures 48 to 52 This is a diagram illustrating a MEMS microphone according to a sixth embodiment of the present invention.

[0098] Figure 53 and Figure 54 It is used to explain the basis and Figures 38 to 41 Graphs of MEMS microphones in different embodiments.

[0099] Figures 55 to 59 It is used to explain the basis and Figure 1 and Figure 52 Figures of different embodiments of MEMS microphones. Detailed Implementation

[0100] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0101] However, the technical concept of the present invention is not limited to the partial embodiments described, but can be implemented in various forms, and within the scope of the technical concept of the present invention, one or more constituent elements can be selectively combined or substituted among embodiments.

[0102] Furthermore, unless explicitly defined and described, the terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as meanings that would be generally understood by those skilled in the art, and commonly used terms (e.g., terms defined in dictionaries) may be interpreted taking into account the meaning of the context of the relevant art.

[0103] Furthermore, the terminology used in this specification is for describing embodiments and is not intended to limit the invention.

[0104] In this specification, unless specifically stated in the phrase, the singular form may include the plural form, and when described as “at least one (or more) of A, B and C”, it may include more than one of all combinations that can be combined with A, B and C.

[0105] Furthermore, when describing components of embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended only to distinguish components from other components, and they do not limit the nature, order, or sequence of the components.

[0106] Furthermore, when a component is described as being “connected,” “joined,” or “interconnected” with another component, the component is not only directly connected, joined, or interconnected with other components, but may also include situations where the component is “connected,” “joined,” or “interconnected” due to another component between other components.

[0107] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" means not only that the two components are in direct contact, but also that one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," it can include not only the meaning of an upward direction relative to a component, but also the meaning of a downward direction relative to a component.

[0108] Modified embodiments according to this embodiment may include some configurations of each embodiment and some configurations of other embodiments. That is, a modified embodiment may include one of various embodiments, but some configurations may be omitted, and some configurations of other corresponding embodiments may be included. Alternatively, it may be the opposite. Features, structures, effects, etc., described in the embodiments are included in at least one embodiment, but are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc., shown in the various embodiments can be combined or modified and implemented in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, content related to these combinations and modifications should be interpreted as being included within the scope of the embodiments.

[0109] Figure 1A MEMS microphone according to an embodiment of the present invention is shown, and Figures 2 to 13 This is a diagram illustrating a MEMS microphone according to a first embodiment of the present invention.

[0110] The MEMS microphone 100 according to an embodiment of the present invention may include a first substrate 110, a second substrate 120 and a MEMS structure 130, and includes a signal processing element 140 and a housing 170.

[0111] A first substrate 110 is disposed at the lower part of the MEMS microphone and has a plate-like shape. The first substrate 110 is a flexible substrate and can be a chip-on-film (COF) substrate or a flexible printed circuit board (FPCB). A COF substrate is a substrate formed by forming circuitry on a base film or mounting elements such as chips, and has a film shape and is much thinner than other substrates. By using a COF substrate as the substrate of the MEMS microphone, the thickness can be significantly reduced. The first substrate 110 is a COF substrate and can also be a 2-Metal COF substrate. A 2-Metal COF is a substrate formed by forming circuitry or mounting elements on both sides of a base film.

[0112] Here, the first substrate 110 (e.g., a 2-Metal COF substrate) can be formed with a thickness of 50 μm or more. Alternatively, it can be formed with a thickness of 20 μm to 100 μm or greater than 100 μm. However, it is not limited to the thicknesses described above. By including vias in the base film, circuits or components formed on both sides can be connected. Here, the vias can be micro-vias and can have a size of less than 25 μm. Compared to a single-sided COF, integration can be increased, design freedom during packaging can be improved, and fine pitch can be achieved by placing circuits or components on both sides. When using only a rigid substrate, it is not easy to apply fine pitch, but when using a COF substrate, fine pitch can be applied, allowing the size of the MEMS microphone package to be reduced by more than 50%. Flexible printed circuit boards (FPCBs) are flexible circuit boards, and because they are thinner than general PCBs, the thickness can be significantly reduced by using flexible printed circuit boards as the substrate for MEMS microphones. In addition, other types of flexible substrates can be included. The first substrate 110 is electrically connected via capacitor 150 and line 190.

[0113] The second substrate 120 is stacked on the first substrate 110 and has a plate-like shape. The second substrate 120 is a rigid substrate and can be a metal plate, SUS, or a reinforcing plate. SUS is a steel grade mixed with iron and chromium to enhance corrosion resistance and is a high-strength substrate. Alternatively, various reinforcing plates made of metal can be used. Additionally, the second substrate 120 may include other types of rigid substrates that can be combined with a housing to maintain shielding. The second substrate 120 is a substrate used to supplement the rigidity of the first substrate 110 and can maintain the flexible shape of the first substrate 110.

[0114] The second substrate 120 includes one or more holes 121. The second substrate 120 is located above the first substrate 110, and the holes 121 are formed in the second substrate 120 such that the first substrate 110 is connected to the second substrate 120 through the holes 121 to expose the upper portion. The first substrate 110 can be electrically connected to a capacitor 150 disposed at the upper portion of the second substrate 120 through the holes 121 formed in the second substrate 120.

[0115] A housing 170 forming an internal space may be provided on the upper part of the second substrate 120. For example... Figure 2 As shown, a housing 170 is disposed on the upper part of the MEMS microphone and may have a cover shape covering the second substrate 120. The housing 170 covers the second substrate 120, thereby forming an internal space. The housing 170 may be a can-shaped material made of metal, or it may be made of various materials such as plastic. The housing 170 may be combined with the second substrate 120. In this case, the housing 170 and the second substrate 120 may be joined by welding. The area where the housing 170 and the second substrate 120 are joined may be joined by micro-welding. By joining the housing 170 and the second substrate 120 by micro-welding, the process of coating and curing can solder or epoxy resin is not required, and there is no need for solder lines or epoxy resin coated areas, so the size can be reduced accordingly.

[0116] MEMS structure 130 and capacitor 150 can be disposed on second substrate 120, and signal processing element 140 can be disposed as follows: Figure 2 The MEMS structure 130 is arranged as shown. It can be disposed within the internal space formed by the second substrate 120 and the housing 170. The MEMS structure 130 includes a body, a backplate, and a resonant plate. A hole 122 can be formed in the first substrate 110 and the second substrate 120 at a position opposite to the lower part of the MEMS structure 130. The cross-sectional area of ​​the hole 122 can be circular, but is not limited thereto. Here, the hole 122 can be an acoustic aperture. This hole can be formed in the region of the housing 170 facing the upper part of the MEMS structure 130. Besides being formed in the region of the housing 170, the hole also corresponds to… Figure 2 Hole 122 in the middle.

[0117] Holes 122 are formed in the first substrate 110, the second substrate 120, or the housing 170, and when the diaphragm vibrates due to the sound pressure generated by sound flowing in from the outside through the holes 122, the acoustic signal can be detected by measuring the capacitance on the back plate. Figure 1 and Figure 2 In the diagram, the backplate is shown as being located above the diaphragm, but of course, the diaphragm can also be located above the backplate.

[0118] The signal detected by the MEMS structure 130 is sent to the signal processing element 140. The MEMS structure 130 and the signal processing element 140 can be electrically connected. At this time, the MEMS structure 130 and the signal processing element 140 are connected to the line 193 by wire bonding, and the signal detected from the MEMS structure 130 through the line 193 can be sent to the signal processing element 140.

[0119] Signal processing element 140 can process electrical signals detected and transmitted from MEMS structure 130. Signal processing element 140 can amplify signals detected by MEMS structure 130. Here, signal processing element 140 may include, but is not limited to, application-specific integrated circuit (ASIC). Signal processing element 140 may be formed as a single module or as a chip. Signal processing element 140 may include ASIC and EN-CAP for coating ASIC.

[0120] Signal processing element 140 can be disposed on the second substrate 120. In this case, signal processing element 140 can be disposed on the second substrate 120 and spaced apart from MEMS structure 130. Signal processing element 140 and MEMS structure 130 are disposed together in the internal space formed by the second substrate 120 and housing 170, and can receive signals from MEMS structure 130. Since signal transmission between MEMS structure 130 and signal processing element 140 occurs within the internal space covered by housing 170, noise can be reduced. Signal processing element 140 can be electrically connected to first substrate 110. Signals processed in signal processing element 140 are transmitted to first substrate 110 and can be transmitted through first substrate 110 to external locations requiring corresponding signals.

[0121] Capacitor 150 can be disposed on the upper part of the second substrate 120 together with MEMS structure 130 and signal processing element 140. When capacitor 150 is installed, the signal-to-noise ratio is improved, and PSRR and PSR noise are also improved. In other words, noise-related performance such as SNR, PSRR, and PSR can be improved by capacitor 150. Capacitor 160 is electrically connected to signal processing element 140 and can remove noise that may occur when signals are processed in signal processing element 140.

[0122] Besides the COF serving as the first substrate 110, the PCB has large conductive areas, pads, patterns, gaps, wire bonding pad sizes, and gap values, so there is no space to build SMT pads on which capacitor components can be mounted. On the other hand, when using a COF substrate, the capacitor 150 can be mounted together with the MEMS structure 130 and the signal processing element 140.

[0123] like Figure 3 and Figure 4 As shown, capacitor 150 can be disposed on the upper part of second substrate 120 and electrically connected to signal processing element 140 and line 192 via wire bonding. Alternatively, capacitor 150 can be electrically connected to second substrate 120 via wire bonding through line 191 passing through hole 121 formed in second substrate 120. At this time, wiring pad 112 is formed on the side of first substrate 110 that contacts second substrate 120, and the wiring pad 112 can be connected to line 192 connected to capacitor 150.

[0124] Capacitor 150 and the first substrate 110 can be connected via line 191, and capacitor 150 can be grounded via line 191. Alternatively, signals can be exchanged with other components, modules, or external devices connected to the first substrate 110.

[0125] like Figure 3 and Figure 4 As shown, the signal processing element 140 receives signals from the MEMS structure 130 via line 193, and the signal processing element 140 can be connected to the first substrate 110 via line 194 passing through a hole 121 formed in the second substrate 120. Wiring pads 111 are formed on the surface of the first substrate 110 that is in contact with the second substrate 120, and the lines 194 of the signal processing element 140 can be connected via the wiring pads 111.

[0126] Signal processing element 140 and first substrate 110 are connected to line 194 via wire bonding, and the signal processed by signal processing element 140 can be transmitted to first substrate 110 via line 194. To protect the wire bonding of lines 381 and 182 of signal processing element 140, EN-CAP can be coated and dried on the upper part of signal processing element 140 to form a protective portion. Thus, signal processing element 140 is not exposed to the outside.

[0127] Signals transmitted to the first substrate 110 can be transmitted to the outside via terminals connected to the outside. Since these terminals must be exposed to the outside rather than the internal space, they can be formed on the lower surface of the first substrate 110. The signal processing element 140 is connected to the first substrate 110, and since terminals connected to the outside can be formed on the lower part of the first substrate 110, signals can be transmitted through vias connecting the upper and lower parts of the first substrate 110. When the first substrate 110 comprises multiple layers, the vias can be formed to penetrate each layer.

[0128] Alternatively, the signal processing element 140 may be embedded inside the first substrate 110 or the second substrate 120. Additionally, the signal processing element 140 may be disposed on the first substrate 110, in which case the second substrate 120 is not stacked at the location where the signal processing element 140 is disposed, or it may have holes corresponding to the shape of the signal processing element 140.

[0129] When the signal processing element 140 is embedded inside the first substrate 110 and / or the second substrate 120, at least a portion of the signal processing element 140 may overlap with at least a portion of the MEMS structure 130 in a first direction, which is the vertical direction of the first substrate 110.

[0130] Alternatively, when the signal processing element 140 is embedded inside the first substrate 110 and / or the second substrate 120, at least a portion of the signal processing element 140 may not overlap with at least a portion of the MEMS structure 130 in a first direction, the first direction being the vertical direction of the first substrate 110.

[0131] Within the internal space formed by the first substrate 110 and / or the second substrate 120 and the housing 170, in addition to the EMS structure body 130 and the signal processing element 140, other elements or modules, such as the capacitor 150, may also be disposed. Other devices or modules may also be embedded within the first substrate 110 and / or the second substrate 120. When other elements, such as the capacitor 150, are embedded together with the signal processing element 140, they can be embedded such that their positions do not overlap or converge. Alternatively, other elements, such as the capacitor 150, may be disposed in the second substrate 120, and only the signal processing element 140 may be embedded.

[0132] The capacitor 150 may be embedded inside the first substrate 110 and / or the second substrate 120. Alternatively, the capacitor 150 may be disposed in the first substrate 110, in which case the second substrate 120 may not be stacked at the location where the capacitor 150 is disposed, or may have a hole corresponding to the shape of the capacitor 150.

[0133] When capacitor 150 is embedded inside the first substrate 110 and / or the second substrate 120, at least a portion of capacitor 150 may overlap with at least a portion of signal processing element 140 or at least a portion of MEMS structure 130 in a first direction toward the upper part of the first substrate 110. Capacitor 150 includes a plurality of capacitors, and at least a portion of at least one capacitor may overlap with at least a portion of signal processing element 140 or at least a portion of MEMS structure 130 in a first direction, the first direction being the vertical direction of the first substrate 110. By closely arranging signal processing element 140 and capacitor 150, capacitance is increased, thereby improving noise-related performance such as SNR, PSRR, and PSR.

[0134] Alternatively, when the capacitor 150 is embedded inside the first substrate 110 and / or the second substrate 120, at least a portion of the capacitor 150 may not overlap with at least a portion of the signal processing element 140 or at least a portion of the MEMS structure 130 in a first direction, the first direction being the vertical direction of the first substrate 110.

[0135] Unlike holes 122 formed in the substrate region facing the lower part of the MEMS structure 130, holes can be formed in the housing 170 facing the upper part of the MEMS structure 130. When holes 122 are formed in the substrate region, the location of the holes may restrict the substrate region where the signal processing element 140 is embedded. However, when holes are formed in the housing 170, since no holes are formed in the substrate region, the restrictions caused by the holes can be eliminated when the signal processing element 140 is embedded inside the substrate. Therefore, greater design freedom can be achieved.

[0136] A flip-chip BGA can be formed using a flip-chip method to bond the signal processing element 140 to the first substrate 110. Alternatively, the signal processing element 140 can be electrically connected to the wiring pads of the first substrate 110 using the BGA method. The signal processing element 140 is disposed on a third substrate (not shown) serving as a separate substrate for the signal processing element 140 to form a flip-chip BGA, and the flip-chip BGA itself can be disposed on the first substrate 110 via ball grid array bonding. In this case, signals from the MEMS structure 130 are transmitted to the first substrate 110 via lines connected to it through wire bonding, and can also be transmitted to the signal processing element 140 via the first substrate 110.

[0137] When the capacitor 150 is disposed on the second substrate 120 and connected to the first substrate 110 by wire bonding through the hole 121 passing through the second substrate 120, it can be as follows: Figure 5The manufacturing process is shown. To mount the capacitor on the substrate, no processing is performed before the packaging process; upon receipt, capacitor 150 can be immediately put into the packaging process. After plasma treatment and baking, the wire bonding process for the capacitor can be performed simultaneously during the chip attachment, curing, and wire bonding processes. At this time, as shown... Figure 6 As shown, epoxy resin is simultaneously coated onto the desired area, and after attaching the ASIC module, which serves as both a capacitor and a signal processing element 140, a MEMS process consisting of curing epoxy resin, coating with silicone resin, attaching and curing the MEMS structure 130 is performed. Then, a wire bonding process can be performed. After the wire bonding process, coating, and curing of the encapsulation, the process can be performed via solder ejection, component pick-and-place, reflow, laser processing, separation, measurement, and winding the package.

[0138] As in Figure 7 In the comparative examples of the present invention, when the capacitor is mounted on the substrate using an SMT process (A) instead of wire bonding, or when the capacitor is mounted as a separate module (B, C), additional steps may be required besides the packaging process. In the case of mounting the capacitor (A), since EN-CAPSULATION needs to be applied to the capacitor already completed by the SMT process, the surface mount process cannot be performed on the capacitor during the surface mount process of the shield. Therefore, the capacitor requires a separate SMT process before entering the packaging process.

[0139] In addition, when the interposer is applied to the capacitor to form a separate module (B, C), a separate process (interposer capacitor) is required to apply the interposer to the capacitor.

[0140] When using Figure 7 When the SMT-mounted capacitor of (A) is electrically connected to the COF substrate corresponding to the first substrate, as Figure 8 As shown, the area of ​​the hole 21 to be etched in the metal plate corresponding to the second substrate must be formed up to the capacitor mounting portion. The acoustic aperture 22 for the MEMS structure must also be formed in the metal plate. The design is constrained because the area of ​​the hole 21 etched corresponding to the capacitor is relatively large.

[0141] On the other hand, in embodiments of the present invention, since the capacitor 150 is electrically connected to the first substrate 110 via a wire bond, only the area through which the wire can pass is etched in the second substrate 120. That is, as Figure 8As shown, the area of ​​the hole 121 in the first substrate 110 can be formed to be smaller. Since the area to be etched is reduced, the number of process management points can be reduced after etching is completed, and the design freedom of the hole shape and size can be increased depending on the structure applied.

[0142] like Figure 9 As shown in (A), the lines can be arranged only on one side of the second substrate to form a straight hole 123 on one side, and as... Figure 9 As shown in (B), by connecting the wire from capacitor 151 to the signal processing element, the hole 124 does not need to extend from one end to the other, but can be formed only in the necessary area. Since the area where the capacitor can be disposed on the second substrate 120 is expanded, capacitors 152 with larger dimensions or capacitances can be applied, thus providing greater freedom in selecting capacitors.

[0143] For example, in Figure 8 In the case of SMT mounting, a total of 8 wire bonding pads are required: 2 for capacitor SMT and 6 for ASIC wire bonding as signal processing components. On the other hand, in Figure 8 and Figure 9 In the embodiment of the invention in (A), a total of 7 pads are required, and Figure 9 (B) and Figure 9 In (C), 6 pads are required. Additionally, in Figure 9 In case (C), the capacitor size (mm) can be 1.0×0.5×0.5, and in other cases, a capacitor size larger than the applicable capacitor size of 0.6×0.3×0.3 can be applied.

[0144] The second substrate 120 is stacked on the first substrate 110 and can be bonded by thermoforming. Alternatively, the second substrate 120 can be bonded using conductive double-sided tape or the like. Additionally, as... Figure 10 As shown, a conductive adhesive layer 180 can be formed between the bonding surfaces of the first substrate 110 and the second substrate 120. An adhesive can be applied to the conductive adhesive layer 180, or conductive double-sided tape can be disposed within the conductive adhesive layer 180. The first substrate 110 and the second substrate 120 can be bonded in various ways to perform substrate bonding. The conductive adhesive layer 180 may include holes 181 that overlap with holes 121 in the second substrate 120.

[0145] Here, the hole 121 in the second substrate 120 can be formed at a predetermined distance from the outer periphery of the second substrate. When a hole is formed in the second substrate 120, as... Figure 11As shown, a hole 181 must be formed in the conductive adhesive layer 180 in the corresponding area to reduce the adhesive area. Furthermore, if the adhesive area is narrower depending on the shape of the hole, problems such as substrate peeling may occur due to weak adhesive strength. As previously stated, in embodiments of the present invention, since the area of ​​the hole 121 is reduced or the design freedom is increased, the hole can be formed with consideration of the adhesive area to increase adhesive force, thereby improving attachment reliability. When the hole 121 is formed close to the outer periphery of the second substrate 120 (i.e., the conductive adhesive layer 180), problems may occur due to the small adhesive area in the outer periphery region. Therefore, when forming the hole 121, it can be formed at a predetermined distance from the outer periphery of both substrates.

[0146] Here, the area of ​​the holes 181 in the conductive adhesive layer 180 can be larger than the area of ​​the holes 121 in the second substrate 120. Because resin from the adhesive in the conductive adhesive layer 180 may flow out during lamination, the area of ​​the holes 181 in the conductive adhesive layer 180 can be formed to be larger than the area of ​​the holes 121 in the second substrate 120. For example, the area of ​​the holes 181 in the conductive adhesive layer 180 can be formed to be 10 μm larger than the area of ​​the holes 121 in the second substrate 120 on one side. Due to the high degree of freedom in hole design, the area of ​​the holes 181 in the conductive adhesive layer 180 is increased; therefore, even if the adhesive area is reduced, the area of ​​the holes 181 in the conductive adhesive layer 180 can still be formed to be larger than the area of ​​the holes 121 in the second substrate 120.

[0147] like Figure 12 As shown, when the hole 21 is formed up to the region overlapping with the capacitor, the two ends of the hole 21 become close to the outer periphery of the conductive adhesive layer 180. For example, as Figure 12 As shown, when the package width D0 is 2 mm, the width D1 of the etched area of ​​the hole 21 is formed to be 1.53 mm. Therefore, due to the conductive adhesive layer 180 formed at both ends, the attachment width of the first substrate 110 and the second substrate 120 is only 0.23 mm for one end D3 and only 0.24 mm for the other end D4. Therefore, there may be extremely narrow portions, which may lead to peeling problems after separation.

[0148] On the other hand, such as Figure 13 As shown, when capacitors are connected via wire connections, due to... Figure 12 Compared to hole 21, the area of ​​hole 124 can be reduced, and the design freedom is increased. Therefore, the two ends of hole 124 can be formed to be spaced apart from the outer periphery of conductive adhesive layer 180 by a certain distance. For example, as Figure 13As shown, when the package width D0 is 2 mm, the width D1' of the etched area of ​​the hole 124 can be narrowed to 1.13 mm. As a result, the attachment width of the first substrate 110 and the second substrate 120 caused by the conductive adhesive layer 180 formed at both ends can be widened to 0.55 mm at one end D3' and to 0.32 mm at the other end D4', thereby increasing the adhesive area and improving the attachment reliability.

[0149] Furthermore, by placing the capacitor 150 on top of the second substrate 120, which is a metal plate, the second substrate 120 can be used to prevent noise caused by sound due to microphone operation from being transmitted to the capacitor 150. This prevents power supply rejection (PSR) performance degradation and improves PSR.

[0150] Figure 14 A MEMS microphone according to a second embodiment of the present invention is shown, and Figures 15 to 24 This is a diagram illustrating a MEMS microphone according to a second embodiment of the present invention.

[0151] The MEMS microphone 200 according to a second embodiment of the present invention includes a first substrate 110, a second substrate 120, a MEMS structure 130 disposed on the second substrate 120, a signal processing element 140, and one or more capacitors 150 and 160. In the detailed description of the first substrate 110, the second substrate 120, the MEMS structure 130 disposed on the second substrate 120, and the signal processing element 140, details will be omitted below. Figures 1 to 13 The detailed descriptions of each configuration in the document are repeated accordingly.

[0152] A MEMS microphone according to an embodiment of the present invention may include multiple capacitors. The MEMS microphone may include capacitors for noise removal, and in this case, the MEMS microphone may include capacitors for power supply noise filtering and capacitors for RF noise filtering. For example, the capacitors for power supply noise removal may include capacitors with a capacitance of 0.1 μm to 10 μm, which can improve SNR performance. The capacitors for RF noise filtering may include one or more capacitors depending on the interference frequency, and in this case, each capacitor may include a capacitor with a capacitance of 10 pF to 500 pF. This can improve SNR or PSRR performance. As MEMS microphones become smaller, there is insufficient space to place capacitors, so it may be impossible to conform to the reference circuit and install capacitors, and therefore, SNR degradation due to power supply noise and SNR and PSRR performance degradation due to RF noise may occur. When the capacitors are placed far away from the MEMS microphone, the performance improvement is usually minimal due to power supply noise and RF noise, and the voltage may drop or the signal quality may deteriorate due to line losses.

[0153] According to an embodiment of the present invention, a MEMS microphone can mount capacitors by applying a stacked structure, in which a capacitor with a relatively large capacity is disposed on a substrate, and a capacitor with a relatively small capacity is stacked with other components.

[0154] The capacitor may include a first capacitor 150 and a second capacitor 161, and the first capacitor 150 may be disposed on a first substrate 110 on which the second substrate 120 is not stacked. In this case, the first capacitor 150 is configured to be spaced apart from the MEMS structure 130 and the signal processing element 140, and is electrically connected to the signal processing element 140 to transmit and receive signals. The second capacitor 161 may be stacked below the signal processing element 140. The capacitance or size of the first capacitor 150 may be larger than the capacitance or size of the second capacitor 161. The first capacitor 150 may be a capacitor performing power supply noise filtering, and the second capacitor 161 may be a capacitor performing RF noise filtering.

[0155] The first electrode of the second capacitor 161, which is stacked on the lower part of the first substrate 110, is electrically connected to the first substrate, and the second electrode of the second capacitor 161 can be electrically connected to the second substrate 120. Here, the first electrode of the second capacitor 161 can be an electrode connected to a signal source or power supply, and the second electrode of the second capacitor 161 can be an electrode connected to ground. The first electrode 162 of the second capacitor 161 can be disposed on the lower part of the second capacitor and bonded to the first substrate 110 by soldering. At this time, a solder resist layer 184 may be included.

[0156] The signal processing element 140 can be connected to the MEMS structure 130 and the first substrate 110 via wires, respectively. When the second capacitor 161 is stacked on the lower part of the signal processing element 140, it may be difficult to electrically connect the lower part of the signal processing element 140 to the first substrate 110, and the signal processing element 140 can be electrically connected to the first substrate 110 via wire bonding.

[0157] The MEMS microphone may include a conductive adhesive layer 183 that electrically connects the second capacitor 161 and the second substrate 120 on the upper part of the second capacitor 161, and a non-conductive adhesive layer 182 that is stacked between the conductive adhesive layer 183 and the signal processing element 140.

[0158] The second substrate 120 may include an etched area in the region where the second capacitor 161 is disposed. Hole etching may be performed in the second substrate 120 to form holes in which the second capacitor 161 can be mounted.

[0159] The first substrate 110 may include a 2-Metal COF as the COF, and the second substrate 120 may include a metal plate. The MEMS microphone substrate composed of the 2-Metal COF and the metal plate allows for a fine-pitch design, ensuring sufficient space for mounting multiple capacitors. Here, an MLCC capacitor as the first capacitor 150 and a silicon capacitor as the second capacitor 161 can be mounted together. The multilayer ceramic capacitor (MLCC) can perform power supply noise filtering, and the silicon capacitor can perform RF noise filtering. The ultra-miniature capacitor is a silicon capacitor and may include a top electrode as the first electrode and a bottom electrode as the second electrode, with each electrode connected to a different node.

[0160] Hole etching of a second substrate 120 (e.g., a metal plate) with a thickness of 50 μm to 100 μm or greater than 100 μm can be applied to ensure space for mounting the second capacitor 161. The thickness of the second substrate 120 is not limited to the aforementioned thickness. Hole etching of the metal plate can be performed on the lower part of the ASIC module, which serves as the signal processing element 140, and a microcapacitor serving as the second capacitor 161 can be mounted in the etched hole area.

[0161] The ultra-miniature capacitor has dimensions of 0.5 × 0.5 mm and a thickness that can be either 0.1 mm or 0.5 × 0.25 mm. The area of ​​the metal plate hole etching can be varied depending on the capacitor size. The etched area is formed to be 0.65 mm × 0.65 mm, allowing the edge of the etched area to be spaced 75 μm away from the second capacitor 161. Since the second substrate 120 is GND, a separation distance can be maintained between the capacitor and the second substrate 120 for insulation.

[0162] The ultra-miniature capacitor 161, serving as the second capacitor, can be mounted via a packaging process including the following steps: mounting the ultra-miniature capacitor via surface mount technology (SMT); applying an underfill; attaching a conductive adhesive; applying a non-conductive epoxy resin; and mounting an ASIC chip. By attaching the conductive adhesive, the ground layer (GND layer) of the ultra-miniature capacitor 161 and the ground portion (GND) of the metal plate serving as the second substrate 120 can be electrically connected. Alternatively, a conductive epoxy resin can be applied and cured instead of attaching the conductive adhesive.

[0163] However, if the ASIC chip body is GND, then a conductive adhesive can be omitted, and the non-conductive epoxy resin can be changed to a conductive epoxy resin after applying UNDER-FILL.

[0164] The second capacitor 161 can be stacked and disposed below the first capacitor 150 instead of below the signal processing element 140. A hole etching region is formed by performing metal plate hole etching on the second substrate 120 below the first capacitor 150, and the second capacitor 161 and the first capacitor 150 can be stacked and disposed.

[0165] The first electrode 153 of the first capacitor 150 is located on the second capacitor 161, and the second electrode 154 of the first capacitor 150 may be located on the second substrate 120. The first electrode of the second capacitor 161 is electrically connected to the first electrode 153 of the first capacitor 150, and the second electrode of the second capacitor may be electrically connected to the first substrate 110. The second substrate 120 may include an etched region in the area where the second capacitor 161 is disposed.

[0166] Here, the size of the second capacitor 161, which is stacked below the first capacitor 150, can be smaller than the size of the first capacitor 150, and hole etching can be performed on the area where the second capacitor 161 is stacked. That is, as... Figure 17 and Figure 18 As shown, a portion of the first capacitor 150 is disposed on the upper part of the second substrate 120, and another portion of the first capacitor 150 may be disposed on the upper part of the second capacitor 161 disposed in the hole etching area of ​​the second substrate 120.

[0167] The ultra-miniature capacitor 161, serving as the second capacitor, can be mounted via a packaging process including the following steps: SMT mounting of the ultra-miniature capacitor; underfill coating; solder paste or conductive epoxy coating; and reflow or curing. Subsequent processes can be determined based on the material applied during the solder paste or conductive epoxy coating process. That is, reflow can be performed during solder paste coating, and curing can be performed during conductive epoxy coating.

[0168] Additionally, the MEMS microphone includes a metal portion 164 stacked on the lower part of the first capacitor 150, a first electrode 153 of the first capacitor 150 located on a second capacitor 161, and a second electrode 154 of the first capacitor 150 may be located on the metal portion 164. Here, the first electrode 153 of the first capacitor 150 can be connected to the first substrate 110 via a wire.

[0169] The second substrate 120 includes a semi-etched region having a metal portion 164 and a second capacitor 161 disposed thereon, and the thickness of the semi-etched region can be thinner than the thickness of the other regions.

[0170] A portion of the first capacitor 150 is directly stacked on the second substrate 120 Figure 17 Different, such as Figure 19 and Figure 20 As shown, the first electrode of the first capacitor 150 is located above the second capacitor 161, and the second electrode may be located on the metal part 164.

[0171] To mount the second capacitor 161, instead of using metal plate hole etching, a half-etching process is applied, etching only a predetermined thickness of the total thickness. To balance the height of the second capacitor 161, which is located at the lower end of the signal electrode (serving as the first electrode of the first capacitor 150), and the height of the ground electrode (serving as the second electrode), a metal sheet (serving as the metal part 164) can be placed at the lower end of the GND electrode (serving as the second electrode of the first capacitor 150). At this time, to mount the second capacitor 161 and the metal part 164, a process of coating epoxy resin (non-conductive), mounting the second capacitor 161 and the metal part 164, and curing is performed in the half-etched area of ​​the metal plate (serving as the second substrate 120). Furthermore, to mount the first capacitor (serving as a power supply noise removal capacitor), it can be mounted through an encapsulation process including the following steps: coating material; mounting the first capacitor; and reflowing or curing depending on the type of material coated. The coated material may include solder paste, conductive epoxy resin, conductive adhesive, etc.; reflow is performed when solder paste is coated; and curing is performed when conductive epoxy resin or conductive adhesive is coated.

[0172] Additionally, the MEMS microphone may include a third capacitor 165 stacked below the first capacitor 150. That is, instead of the metal portion 164, the third capacitor 165 may be stacked below the first capacitor 150. Figure 21 and Figure 22As shown, the first electrode 153 of the first capacitor 150 is located on the second capacitor 161, and the second electrode 154 of the first capacitor 150 can be located on the third capacitor 165. The first electrode 153 of the first capacitor 150 can be connected to the first substrate 110 via a wire, and the second electrode 154 of the first capacitor 150 can be electrically connected to the first electrode 166 of the third capacitor 165.

[0173] The second substrate 120 includes a semi-etched region where a second capacitor 161 and a third capacitor 165 are disposed, and the thickness of the semi-etched region can be thinner than the thickness of the other regions.

[0174] To maintain balance when placing the first capacitor 150, a third capacitor 165 can be applied. This third capacitor 165 is another capacitor, not the metal part 164. Here, the third capacitor 165 can be a miniature capacitor. The first electrode 153 of the third capacitor 165 can be connected (i.e., connected in series) to the second electrode 154 of the first capacitor 150. By applying the third capacitor 165, it can be used as a series capacitor connected in series in an equivalent circuit. Through the series connection of the first capacitor 150 and the third capacitor 165, various capacitor capacitances can be constructed by combining the two capacitors. The process of installing the third capacitor 165 corresponds to the process of installing the second capacitor 161.

[0175] The MEMS microphone includes three capacitors: a first capacitor 150; a second capacitor 161; and a fourth capacitor 167, wherein a second substrate 120 may be disposed on an un-laminated first substrate 110. The first capacitor 150 is disposed on the first substrate 110 on which the second substrate 120 is not laminated; the second capacitor 161 is laminated below the first electrode 153 of the first capacitor 150; the fourth capacitor 167 is laminated below the second electrode 154 of the first capacitor 150; the first electrode of the second capacitor 161 is electrically connected to the first electrode 153 of the first capacitor 150; the second electrode of the second capacitor 161 is electrically connected to the first substrate 110; the first electrode of the fourth capacitor 167 is electrically connected to the first substrate 110; and the second electrode of the fourth capacitor 167 may be electrically connected to the second electrode 154 of the first capacitor 150. The first electrode 153 of the first capacitor 150 can be connected to the first substrate 110 via a wire.

[0176] At least a portion of the first capacitor 150 is disposed on the upper part of the second substrate 120. Figures 17 to 22 Different, such as Figure 23As shown, the first capacitor 150, the second capacitor 161, and the fourth capacitor 167 can all be disposed on the first substrate 110 on which the second substrate 120 is not stacked. Through metal plate hole etching, hole etching regions in which the second substrate 120 is not stacked are formed on the second substrate 120, and the first capacitor 150, the second capacitor 161, and the fourth capacitor 167 can be mounted in the hole etching regions. At this time, unlike... Figure 21 The first electrode of the third capacitor 165 and the fourth capacitor 167 are electrically connected to the first substrate 110, and the second electrode of the fourth capacitor 167 can be electrically connected to the second electrode 154 of the first capacitor 150. Therefore, the third capacitor 165 is not connected in series with the first capacitor 150, but in parallel. Alternatively, they can be connected in reverse or in series.

[0177] The first electrode of the fourth capacitor 167 can be electrically connected to the AVDD pad formed on the lower part of the first substrate 110. The second electrode of the second capacitor 161 can be electrically connected to the DVDD pad formed on the lower part of the first substrate 110.

[0178] Here, the first capacitor 150 performs noise removal for the DVDD power supply, and the fourth capacitor 167 can perform noise removal for the AVDD power supply. In other words, each of the capacitors for removing power supply noise and RF noise in the DVDD-side path, and the capacitors for removing RF noise in the AVDD-side path, can play different roles.

[0179] When C1 is included as the first capacitor 150 and C2 is included as the second capacitor 161, the connection relationship can be as follows: Figure 24 The configuration shown in (A) is as follows; when C1 as the first capacitor 150, C2 as the second capacitor 161, and C3 as the third capacitor 165 are included, the connection relationship can be as follows. Figure 24 The configuration shown in (B) is as follows; and when C1 is the first capacitor 150, C2 is the second capacitor 161 and C4 is the fourth capacitor 167, the connection relationship can be as follows: Figure 24 The configuration shown in (C) is as follows. In this configuration, C1 performs DMS power supply noise removal, C2 performs RF noise removal, and C3 is connected in series with C1 to implement various capacitor capacities. C4 performs power supply noise removal, but C1 can be configured for DVDD, and C4 can be configured for AVDD.

[0180] Figure 25 A MEMS microphone according to a third embodiment of the present invention is shown; Figure 26 This is a diagram illustrating a MEMS microphone according to a third embodiment of the present invention.

[0181] A MEMS microphone according to an embodiment of the present invention includes: a first substrate 110; a second substrate 120, the second substrate 120 being stacked on at least one region of the first substrate 110; a MEMS structure 130 disposed on the second substrate 120; a signal processing element 140; and a capacitor element 155. The capacitor element 155 includes a capacitor 150 and an interposer layer 156 stacked on the lower portion of the capacitor 150. The capacitor element 155 may be stacked on the first substrate 110 on which the second substrate 120 is not stacked. In the detailed description of the first substrate 110, the second substrate 120, the MEMS structure 130 disposed on the second substrate 120, the signal processing element 140, and the capacitor 150, details related to the first substrate 110, the second substrate 120, the MEMS structure 130 disposed on the second substrate 120, the signal processing element 140, and the capacitor 150 will be omitted below. Figures 1 to 24 The detailed descriptions of each configuration in the document are repeated accordingly.

[0182] The MEMS microphone according to embodiments of the present invention uses a COF substrate and a metal plate to mount capacitor components inside the MEMS microphone, but this may have side effects. When an AC bias is applied to the MEMS microphone with internally mounted capacitor elements, due to the characteristics of MLCC capacitors, which simultaneously possess ferroelectric / multilayer piezoelectric / dielectric properties, a deflection occurs depending on the applied power supply (AC bias). In other words, when an AC bias is applied, micro-vibrations of a few pm to a few nm occur due to the expansion / contraction of the mounted capacitors. Therefore, these vibrations may be transmitted to the substrate, resulting in audible noise due to the micro-vibrations of the substrate. Due to this audible noise, power supply rejection (PSR) performance may be reduced.

[0183] According to an embodiment of the present invention, the capacitor element 155 includes an interposer layer 156 in the lower part of the capacitor 150 to remove audible noise. In other words, the capacitor is not directly mounted on the substrate, but is mounted on the interposer layer, which is a physical structure, and then mounted on the substrate, thereby absorbing the vibration of the interposer layer and preventing audible noise.

[0184] Intermediate layer 156 can be disposed between capacitor 150 and first substrate 110; miniaturization is necessary for the intermediate layer capacitor used inside MEMS microphone; and capacitor element 155 including intermediate layer also needs to be miniaturized so that its size is smaller than 0.6mm × 0.3mm × 0.35mm as the size of capacitor.

[0185] The capacitor element 155, installed inside a 3mm×2mm×0.825mm package, has a capacitor size of 0.6mm×0.3mm×0.35T mm, and the size can be less than 0.9mm×0.4mm×0.194mm.

[0186] By mounting capacitor 150 on top of interposer 156, capacitor element 155 can be formed into a device component. Interposer 156 may include any one of FR4 printed circuit board, metal plate, lead frame, ceramic printed circuit board (ceramic PCB), and metal printed circuit board (metal PCB).

[0187] Here, the interposer 156 includes an FR4 printed circuit board, and the capacitor 150 can be surface-mounted on the printed circuit board to form a capacitor element.

[0188] Additionally, the interposer 156 includes a metal plate, and the capacitor 150 can be mounted on the metal plate to form a capacitor element. Here, the metal plate includes a first metal plate and a second metal plate, and the first metal plate and the second metal plate can form a bridge structure that is respectively connected to the two electrodes of the capacitor.

[0189] like Figure 26 As shown, an FR4 printed circuit board for manufacturing capacitor elements is used. The capacitor 150 is surface mounted (SMT), and separation is performed to check the status of individual products. Roll-up or tray packaging is performed, and it can be surface mounted on the board in the MEMS microphone packaging process.

[0190] When using metal plates, capacitors are mounted on an array of metal plates. In this case, the metal plates include a first metal plate and a second metal plate, and the first and second metal plates can form a bridge structure that is respectively connected to the two electrodes of the capacitor, such that each electrode is connected to a different node. Then, separation is performed, the status of individual products is checked, winding or tray packaging is performed, and it can be surface-mounted onto a substrate during the MEMS microphone packaging process.

[0191] As described above, the capacitor element 155, formed as a single device component, can be soldered to a first substrate 110 on which the second substrate 120 is not stacked. At this time, metal plate hole etching can be performed on the second substrate 120 to form hole etched regions, and the capacitor element 155 can be disposed in the hole etched regions.

[0192] The capacitor element 155 is arranged spaced apart from the signal processing element 140 but can be electrically connected, and the signal processing element 140 may include an ASIC module. The first substrate 110 may be a flexible substrate, the second substrate 120 may be a rigid substrate, and the first substrate 110 and the second substrate 120 may be joined by thermoforming.

[0193] Figure 27 A MEMS microphone according to a fourth embodiment of the present invention is shown; and Figures 28 to 37 This is a diagram illustrating a MEMS microphone according to a fourth embodiment of the present invention.

[0194] A MEMS microphone according to an embodiment of the present invention includes: a first substrate 110; a MEMS structure 130; and a signal processing element 140. In the detailed description of the first substrate 110, the MEMS structure 130, the signal processing element 140, and the capacitor 150, details related to... will be omitted below. Figures 1 to 26 The detailed descriptions of each configuration in the document are repeated accordingly.

[0195] A MEMS microphone according to an embodiment of the present invention may include a first substrate 110 and a second substrate 120 stacked on at least one region of the first substrate 110. The first substrate 110 is COF and may include 2-Metal COF, and the second substrate 120 may include a metal plate.

[0196] When using an FR4 rigid substrate, fine pitch rules cannot be applied, and there are limitations to reducing the substrate thickness. Instead, a metal plate bonding structure can be used by applying fine pitch rules using 2-Metal COF, where bending issues are improved, allowing it to be used as a ground plane.

[0197] When bonding the first substrate 110 and the second substrate 120, a conductive adhesive layer 180 can be used, such as Figure 27 and Figure 28 As shown. A conductive adhesive layer 180 can be disposed between the first substrate 110 and the second substrate 120, and the first substrate 110 and the second substrate 120 can be joined by thermocompression bonding. First, the first substrate 110 is joined to the conductive adhesive layer 180 by performing a lamination process, and the second substrate 120 can be joined to the upper part by performing a lamination process. Afterwards, the substrate can be formed by a thermocompression process. For example, the lamination process can be performed at 110°C for 20 seconds, and the thermocompression process can be performed at 160°C for 60 minutes and 20 kgf·cm.

[0198] The first substrate 110 and the second substrate 120 can be directly bonded without the conductive adhesive layer 180. In this case, an SMT process or a bonding process can be applied.

[0199] During the SMT process, solder is applied to the copper area of ​​the 2-Metal COF layer of the first substrate 110. The solder application area can be varied depending on factors such as attachment reliability and metal board rotation. After solder application, a metal board serving as the second substrate 120 can be placed, and reflow can be performed to bond the first substrate 110 and the second substrate 120. The metal board can be transported in reel and tape or on a tray. The reflow process can be customized based on specifications such as the applied solder, COF, and metal board thermal balance conditions.

[0200] During the bonding process, conductive epoxy resin is coated or a conductive chip attachment film is attached to the copper area of ​​the 2-Metal COF layer of the first substrate 110. Due to the viscosity of the epoxy resin, the epoxy resin coating or chip attachment film area can be varied to ensure fluidity. Afterwards, a metal plate serving as the second substrate 120 can be placed, and curing can be performed to bond the first substrate 110 and the second substrate 120. The metal plate can be transported in a reel / tape type or a tray type. In the curing process, the curing conditions can be varied depending on the curing temperature and time of the coated epoxy resin, chip attachment film, etc.

[0201] The upper adhesive layer can be stacked on the upper part of the first substrate 110 and the second substrate 120. The upper adhesive layer can be stacked on the upper part of the second substrate 120, and the MEMS structure 130 and the signal processing element 140 can be disposed on the upper adhesive layer.

[0202] When the MEMS structure 130 is mounted on a metal plate serving as the second substrate 120, the MEMS silicon may be over-cured due to its high thermal conductivity, leading to MEMS stress. When MEMS stress occurs, initial sensitivity decreases and calibration becomes impossible, and the SNR may decrease due to the increased noise floor. This can be improved by laminating an adhesive layer on top of the second substrate 120.

[0203] The upper adhesive layer may include a capping layer or photoresist (PSR). For example... Figure 29 As shown, PSR126 can be stacked on top of the second substrate 120, or the cover layer 186 can be as follows: Figure 30 The layered structure is shown. The capping layer is a material made by coating a semi-cured adhesive onto polyimide (PI), and PI has a higher thermal conductivity than nickel silver or SUS, which are used as materials for the metal plate. The thermal conductivity of PI is 0.12 W / (m·K), that of the nickel silver plate is 45 W / (m·K), and that of the SUS plate is 16.2 W / (m·K), which is 375 times higher than that of nickel silver and 135 times higher than that of SUS.

[0204] Even with a stacked cover layer or PSR, the overall substrate thickness is less than 0.21 mm based on a 100 μm metal plate thickness, so the entire substrate can be thinner than when using existing FR4 rigid substrates.

[0205] MEMS stress can be reduced by directly bonding the MEMS structure 130 to the upper adhesive layers 126 and 186. Additionally, when solder is applied during the bonding of the first substrate 110 and the second substrate, a lack of solder due to solder separation during the reflow process prevents hermetic shielding, potentially leading to reduced SNR performance due to leakage paths. The capping layer and PSR act as solder resist and prevent solder separation.

[0206] A photoresist can be used to form a substrate without laminating a metal plate as the second substrate 120. A first photoresist layer 126 and a second photoresist layer 126 may be respectively included on the upper and lower parts of the first substrate 110. The second substrate 120 can directly contact the first photoresist layer 126 and the second photoresist layer 126 to form a substrate.

[0207] like Figure 31 As shown, the PSR can be stacked on the upper and lower parts of the first substrate 110. Since the PSR is thinner than the metal plate, the thickness of the substrate can be reduced. In addition to existing FR4 rigid PCBs, the thickness can be lower than that when using a metal plate, thereby ensuring SNR performance and reducing substrate manufacturing costs.

[0208] For example, the PSR thicknesses of the first photoresist layer 126 and the second photoresist layer 126 can be applied differently, ranging from 20 μm to 55 μm. Here, the thickness can be changed in 5 μm increments, thereby allowing the thickness of the entire substrate to be adjusted.

[0209] Therefore, expansion of the internal volume (back-volume) is possible. It can be seen that applications... Figure 27 The internal volume of the metal plate is Figure 33 V1 in, and applying PSR126 Figure 32 The internal volume is Figure 34 V2 in the middle, which increases the internal volume.

[0210] The metal plate serving as the second substrate 120 can be used as a housing instead of a substrate. For this purpose, the second substrate 120 is formed to include a base facing the first substrate 110 and side plates extending from the outer periphery of the base to the upper portion, and may include a cover 127 covering the second substrate 120. The cover 171 may contact the end of the side plate of the second substrate 127. The side plate may have a certain thickness, and the cover 171 may contact the upper surface of the end plate. The second substrate 127 and the cover 171 can be joined by welding. In this case, the first substrate 110 and the cover 171 may be made of the same material, and the first substrate 110 and the cover 171 may include COF, and may include 2-Metal COF.

[0211] When forming the shape of the second substrate 120, a metal plate including side plates is manufactured and bonded to the first substrate 110, or a plate-shaped metal plate is used as both the base and side plates, and the plate-shaped metal plate can be attached using eutectic bonding or conductive adhesive. This offers the advantage of separation. The metal plate can be used in various ways, including nickel silver, SUS, lead frames, FR4, etc.

[0212] like Figure 34 As shown, the second substrate 120 is formed in a plate shape and differs from the housing 170 that covers the upper part and is joined to form the internal space, as... Figure 35 As shown, the second substrate 127 can be used as a base and side plate to form the internal space, and the cover 171 can cover the second substrate 127 to form the internal space. Figure 36 As shown, the MEMS structure 130, signal processing element 140, etc. can be arranged in the internal space.

[0213] By changing the shape of the metal plate serving as the second substrate, 2-Metal COF can be used not only as the first substrate but also as a cover. When 2-Metal COF is used as a cover, the internal volume (rear volume) can be expanded by reducing the thickness compared to existing shielding covers. Figure 34 The internal volume of the metal plate used in the plate shape is Figure 37 V1 in, and the shape of the metal plate is changed and 2-Metal COF is used as a cover. Figure 35 The internal volume is Figure 34 As can be seen from V3, the internal volume increases. Therefore, compared to the cost of manufacturing a metal cover, a cost reduction can be expected by utilizing 2-Metal COF. By using 2-Metal COF as the cover, the cost of the shielding is reduced, and when manufactured to the same specifications as the first substrate, material management is easier and costs can be reduced because it can be manufactured as one type of COF.

[0214] The first substrate 110 is a flexible substrate; the second substrate 120 may be a rigid substrate; the second substrate 120 may contain any one of nickel silver, SUS, ceramic and FR4; the second substrate 120 may include a capacitor disposed on the second substrate 120 and spaced apart from the signal processing element 140; and the signal processing element 140 may include an ASIC module.

[0215] Figure 38 A MEMS microphone according to a fifth embodiment of the present invention is shown; Figures 39 to 46 This is a diagram illustrating a MEMS microphone according to a fifth embodiment of the present invention.

[0216] A MEMS microphone according to an embodiment of the present invention includes: a first substrate 110; a second substrate 120, the second substrate 120 being stacked on at least one region of the first substrate 110; a housing 170; a MEMS structure 130 disposed on the second substrate 120; and a signal processing element 140. In the detailed description of the first substrate 110, the MEMS structure 130 disposed on the second substrate 120, the signal processing element 140, and the capacitor 150, details related to... will be omitted below. Figures 1 to 26 The detailed descriptions of each configuration in the document are repeated accordingly.

[0217] The housing of the MEMS microphone according to an embodiment of the present invention can be formed of a shield. The shield can be made of nickel silver or SUS. In the following, when referring to… Figures 27 to 37 When describing a MEMS microphone, the housing will be described as shield 170.

[0218] When a shield is applied to a MEMS microphone using an FR4 rigid PCB, solder is applied to the surface copper layer, the shield is mounted, and a reflow process is performed. At this time, vias are formed in the surface copper layer, reducing the area available for soldering and mounting the shield. Furthermore, reliability may be compromised due to issues such as solder voids, shield rotation or tilting after reflow, and deterioration of bonding adhesion after bonding.

[0219] The MEMS microphone according to an embodiment of the present invention improves the above-mentioned problems by bonding the shield to a metal plate serving as a second substrate 120, thereby improving the shield performance (SNR) and bonding reliability.

[0220] The shield 170 is bonded to the second substrate 120. For example... Figure 38 As shown, the shield 170 can be bonded to the outer periphery of the second substrate 120. Here, the shield 170 can be made of the same material as the second substrate. The second substrate 120 and the shield 170 can be made of SUS or nickel silver and are bonded together. The second substrate 120 and the shield 170 can be bonded using solder 187.

[0221] Nickel-silver is a material containing 15% to 30% zinc and 10% to 20% nickel in copper, and it can be soldered in its raw state without plating. When plating is applied to the shielding cover 170 mounting area, it can improve solder joint adhesion. Nickel-gold (Ni+AU) plating can be used. Both chemical plating and electrolytic plating processes can be applied.

[0222] Although SUS contains Ni, solder joint adhesion may be reduced without plating. Therefore, plating can be applied. Unlike nickel-silver, plating adhesion to the surface may be reduced when chemical plating is applied; therefore, electrolytic plating is used to perform the plating process.

[0223] When the second substrate 120 and the shield 170, which are joined together, are made of the same material, the thermal diffusivity of the two components is the same, thereby improving the reliability of the joint. For example, if the second substrate 120 is a metal plate made of nickel silver, solder jointing can be performed without gold plating because thermal equilibrium is achieved, thereby improving the reliability of the joint.

[0224] In the case that the second substrate 120 is an SUS metal plate, since it is impossible to solder to the SUS as a raw material, plating can be applied to the part where the shield 170 is placed, and plating can also be applied to the shield to achieve thermal balance.

[0225] When the shield 170 is attached, the shield 170 can be attached to the second substrate 120 in various ways, such as leaded type, non-leaded type and shell type.

[0226] The lead type is one where the shield legs are formed on the outside of the shield, and the bonding area between the substrate and the shield legs is wide, which improves bonding reliability.

[0227] Non-leaded types do not have straight shield legs extending downwards from the sidewalls, allowing for a reduction in the external dimensions of the shield due to these legs. This enables a smaller package size or allows for an increase in internal area while maintaining the same package size. For example, the width of the lead portion needs to be approximately 60 μm or more, whereas for non-leaded types, the substrate size can be reduced to accommodate the lead width if the internal area remains the same. In this case, the bonding area between the substrate and the shield is reduced.

[0228] The shell-wall type is based on the non-lead type structure, but the bridging portion is formed in the shape of a shell wall. Various structures can be applied to substrate structures such as metal plates.

[0229] The second substrate 120 may include a mounting portion 128, on which a shielding cover 170 is disposed in a region to which the shielding cover 170 is joined. Figure 39 and Figure 40In this process, the mounting portion 128 can be formed in the area where it joins with the shielding cover 170. The thickness of the mounting portion 128 can be made thinner than the thickness of other areas outside the mounting portion. The mounting portion 128 can be formed by etching the second substrate 120. At this time, a metal plate half-etch can be performed on the second substrate 120; the shielding cover 170 can be placed on the mounting portion 128; and soldering can be performed using solder 187; the area joined to the second substrate 120 can be increased, thereby improving the joint strength; and hermetic shielding can be performed. As a result, the joint reliability is improved, and improvements in SNR performance and tolerances become possible.

[0230] The shield 170 can be formed in various shapes, such as leaded type, non-leaded type, and shell type. The shield 170 is composed of an upper plate 172 and a side plate 173, and the shield 170 may include a leaded portion in the case of leaded type and a protrusion 174 in the case of shell type.

[0231] The shield 170 includes a plate-shaped upper plate 172 serving as a base and a side plate 173 extending from the outer periphery of the upper plate 172 to the lower portion. In the non-lead type, the ends of the side plates 173 are formed to engage the surface of the second substrate 120, rather than being lead-type or shell-type.

[0232] In the lead-type case, the shield 170 may include a lead portion extending outward from the end of the side plate 173. The lead portion is formed perpendicular to the downward direction at the end of the side plate 173 and extends outward. The lead portion may extend outward at a predetermined angle not perpendicular to the downward direction, or it may extend in a curved shape. The lead portion may be formed to extend inward instead of outward, and may have various shapes to expand the bonding area. The placement portion 128 of the second substrate 120 may be formed to correspond to the shape of the lead portion. Figure 41 As shown, the mounting portion 128 is included in the area corresponding to the lead portion and can be joined by solder 187.

[0233] In the case of a shell-wall type, the shield 170 extends from the end of the side plate 173 to the lower portion and may include a plurality of protrusions 174 spaced apart from each other. The protrusions 174 may be formed to be spaced apart along the side plate 173 at predetermined intervals, such as... Figure 42 As shown.

[0234] The second substrate 120 may not be stacked in the region corresponding to the protrusion 174 of the shield 170. In the region corresponding to the protrusion 174 of the shield 170, the second substrate 120 is etched such that the end of the protrusion 174 of the shield 170 can be bonded to the first substrate 110. That is, the end of the side plate 173 where the protrusion 174 of the shield 170 is not formed is bonded to the second substrate 120, and the protrusion 174 of the shield 170 can be bonded to the first substrate 110.

[0235] The area of ​​the second substrate 120 that is joined to the end of the shield 170 can also be formed by half-etching to be thinner than other areas.

[0236] The end of the side plate 173 of the shield 170 and the end of the protrusion 174, as well as the end of the side plate of the shield 170, can be joined to the second substrate 120. When a conductive adhesive layer 180 is included between the first substrate 110 and the second substrate 120, the side surface of the protrusion 174 can be joined to the second substrate 120 and the conductive adhesive layer 180. That is, compared with the non-lead type where only the end of the side plate 173 is joined, the joint area can be increased and the joint strength can be improved.

[0237] The metal plate is fully or partially etched onto the second substrate 120, and the shield is formed as a shell wall type including the protrusion 174, thereby allowing for a more robust and deeper placement. In the bonding region where the protrusion 174 of the shield 170 is formed, the placement surface of the shield 170 and the upper copper of the 2-Metal COF of the first substrate 110 are bonded, and in the portion where the protrusion 174 is not formed, the side surface of the bonding metal plate is bonded to the surface layer region. When the second substrate 120 is a nickel-silver metal plate, a separate plating process for bonding may not be necessary; and in the case of SUS, a plating process can be applied. Even in the case of nickel-silver, plating can be applied to increase solder bond adhesion.

[0238] The epoxy or silicone resin filling the steps in the areas where the shielding cover 170 can be joined with the first substrate 110 and the second substrate 120 can be bonded together with the shielding cover 170. For example... Figure 43 As shown, when the shield 170, which has the same shape as the shell wall, and the second substrate 120 are joined, a stepped portion may be present, so that it can be joined together with the material 188 used to seal the shield. In addition, the portion with the protrusion is joined with the material used to make close contact with the upper copper pads of the first substrate 110 and the shield, thereby increasing the joint area and increasing the joint reliability and sealing tightness of the shield.

[0239] The material 188 used for attaching to the shield may comprise at least one of solder paste, silver epoxy resin, conductive epoxy resin, and silicone. As a subsequent process, the solder paste is reflowed; in the case of a nickel-silver metal plate, it can be applied regardless of plating; and in the case of SUS, plating may be required. As a subsequent process, the silver epoxy resin requires oven curing, and if the metal plate is nickel-silver or silver, it can be applied without plating. The conductive epoxy resin and silicone resin undergo oven curing, and if the metal plate is nickel-silver or silver, both can be applied without plating.

[0240] When protrusions are formed in the corner region of the second substrate 120, the shield can be more securely joined. The upper plate 172 of the shield 170 has a square shape; the side plates 173 of the shield 170 include first side plates to fourth side plates extending from the upper plate; and a plurality of protrusions 175 can be formed by extending from the ends of the side plates to the lower portion by means of the shape of the edges along which adjacent two side plates from the first side plate to the fourth side plate are joined. Figure 44 and Figure 46 As shown, the protrusion may include four protrusions 175 formed in the corner region, and the four protrusions 175 may be formed on two adjacent side plates in the corner region, respectively. Epoxy or silicone resin 188 filling the steps in the areas where the shielding cover 170 is joined to the first substrate 110 and the second substrate 120 may be bonded together with the shielding cover 170. As... Figure 45 As shown, the material 188 used to attach to the shield can be joined together.

[0241] An all-metal plate etching is performed on the second substrate 120 in a manner corresponding to the shape of the protrusion 175, thereby forming a dam-to-dam bridging structure; and by placing the protrusion 175 between the dams, the reliability and airtightness of the joint can be improved, and the shield can be prevented from rotating after reflow.

[0242] The second substrate 120 is fully etched, allowing the legs of the protrusions serving as the shield 170 to be positioned between the dams, and allowing bridging structures to be applied between the dams. Bridging structures can be applied to prevent the second substrate 120 from being divided into two. The copper pads of the 2-Metal COF of the first substrate 110 can be exposed in the fully etched area between the dams where there are no bridging structures.

[0243] The metal plate of the second substrate 120, which is used to bridge the dam-to-dam structure, and the 2-Metal COF of the first substrate 110 can be joined by a conductive adhesive layer 180, and the material 188 for attaching to the shield can be joined together. The material 188 for attaching to the shield may include at least one of solder paste, silver epoxy resin, conductive epoxy resin, and silicon.

[0244] After coating the material 188 for attaching the shield and installing (pick and place) the shield so that the protrusion 175 of the shield is inserted between the dams, a reflow or oven curing process (depending on the bonding material), reflow (solder), oven curing (epoxy resin, silicone, AG epoxy resin, etc.) can be performed.

[0245] Figure 47 A MEMS microphone according to a sixth embodiment of the present invention is shown; and Figures 48 to 52 This is a diagram illustrating a MEMS microphone according to a sixth embodiment of the present invention.

[0246] A MEMS microphone according to an embodiment of the present invention includes: a first substrate 110; a second substrate 120, the second substrate 120 being stacked on at least one region of the first substrate 110; a housing 170; a MEMS structure 130 disposed on the second substrate 120; and a signal processing element 140. In the detailed description of the first substrate 110, the MEMS structure 130 disposed on the second substrate 120, and the signal processing element 140, details will be omitted below. Figures 1 to 46 The detailed descriptions of each configuration in the document are repeated accordingly.

[0247] In the case of FR4 rigid substrates, increased cost for the application of chamber substrates is unavoidable. Furthermore, the area where chambers can be applied is limited by the design constraints of features such as line spacing, gaps, and conductive sections. In the case of flip-chip bonding, it needs to be applied to the surface of the upper layer of the FR4 rigid substrate, which inevitably increases thickness and reduces internal volume. Thickness can be reduced by embedding MEMS and ASICs; however, this requires a re-design layer (RDL) process for the MEMS and ASICs. Increased cost is unavoidable due to the need for high-specification processes to embed them within the PCB.

[0248] According to an embodiment of the present invention, the MEMS microphone can achieve various chamber structures by etching the second substrate 120.

[0249] The second substrate 120 includes an etched region on which a MEMS structure 130 or a signal processing element 140 is disposed, and the thickness of the etched region is formed to be thinner than the thickness of other regions besides the etched region. A capacitor 150 disposed in the etched region of the second substrate 120 and spaced apart from the signal processing element 140 may be included in the internal space of the housing 170. The signal processing element 140 may include an ASIC module.

[0250] The chamber can be secured by applying a partial etch of a portion of the second substrate 120 in the area where the MEMS structure 130, signal processing element 140, or capacitor 150 is located. For example... Figure 47 As shown, the thickness of the semi-etched region W2 can be made thinner than the thickness of other regions W1 to form a cavity. The thickness in which the semi-etching is performed can vary depending on the thickness of the metal plate serving as the second substrate 120.

[0251] For example, when half-etching is applied to a metal plate with a thickness of 0.1 mm, it can be etched to 0.05 mm. If the metal plate thickness is 0.2 mm, then when applying half-etching, it can be set to 0.1 mm. It goes without saying that it can be etched to be thicker or thinner than half the thickness. Thus, for the same package size, the internal volume can be improved.

[0252] When the MEMS structure 130 is bonded to the second substrate 120, epoxy resin or silicon can be coated within the etched area. The semi-etched area can serve as a reference for coating silicon (for MEMS chip mounting) or epoxy resin (for silicon chip mounting), and the flow of silicon or epoxy resin can be suppressed before curing. Silicon can be coated onto the etched area corresponding to the region of the MEMS structure 130, and epoxy resin can be coated onto the etched area corresponding to the region of the signal processing element 140 or capacitor 150. The unetched area of ​​the second substrate 120 between the two areas can also serve as a dam to prevent the silicon and epoxy resin from mixing.

[0253] The second substrate 120 may not be stacked in the area where the MEMS structure 130 or signal processing element 140 is disposed. The chamber can be ensured not only by partial etching but also by hole etching to form holes. The second substrate 120 can be removed by performing hole etching on the area where the MEMS structure 130 or signal processing element 140 is disposed. Hole etching removes the entire second substrate to form holes, therefore it can be referred to as complete etching.

[0254] Etching can be applied only to a portion of the area where the MEMS structure 130, signal processing element 140, and capacitor 150 are located.

[0255] like Figure 48 As shown, complete etching can be applied to areas of the MEMS structure 130, while etching can be omitted from areas of the signal processing element 140 or capacitor 150. Figure 49 As shown, full etching can be applied to areas of the MEMS structure 130, and partial etching can be applied to areas of the signal processing element 140 or the capacitor 150. Figure 50As shown, complete etching can be applied to all areas of the MEMS structure 130, signal processing element 140, and capacitor 150.

[0256] The chamber can be secured by applying full and partial etching in various ways. This allows for improved internal volume based on the same package size; the fully etched and partially etched areas can serve as references for coating silicon (for MEMS chip mounting) and epoxy (for silicon chip mounting); and can suppress the flow of either silicon or epoxy before curing. Silicon can be coated onto the etched areas corresponding to the MEMS structure 130, and epoxy can be coated onto the etched areas corresponding to the signal processing element 140 or capacitor 150. The unetched area of ​​the second substrate 120 between these two areas can also serve as a dam to prevent mixing of silicon and epoxy.

[0257] An etched area of ​​the second substrate 120 can be etched on the surface facing the first substrate 110 to form a cavity. For example... Figure 51 As shown, when etching is applied to the second substrate 120, the etching can be applied to the lower part of the second substrate 120 instead of the upper part, that is, the etching can be applied to the surface facing the first substrate 110. An internal cavity space covered by the second substrate 120 can be formed. Wiring electrically connected to the first substrate 110 can be provided in the cavity.

[0258] The routing freedom of the 2-Metal COF can be ensured by applying half-etching towards the lower surface of the second substrate 120 (i.e., towards the 2-Metal COF that serves as the first substrate 110) rather than the upper surface of the second substrate 120. When the routing freedom of the 2-Metal COF is ensured, the design freedom of reflections can be expanded, such as minimizing line losses and parasitic impedance, thereby improving SNR performance by minimizing noise levels.

[0259] In addition, it can ensure 2-Metal COF wiring freedom while maintaining the existing package structure, and by ensuring wiring freedom, the arrangement of ASIC and MLCC capacitors can be changed and expanded in narrow space.

[0260] Full or partial etching can be applied to the second substrate 120, and flip-chip bonding of the MEMS structure 130 or signal processing element 140 can be applied. For example... Figure 52 As shown, it is possible to directly bond the MEMS structure 130 or signal processing element 140 to the flip chip bonding of the first substrate 110 using solder 189, and the MEMS structure 130 can be flipped up and down for flip chip bonding.

[0261] This allows for an expansion of the internal volume and improved SNR. By performing flip-chip bonding, wire bonding lines are eliminated because the ASIC and 2-Metal COF signal lines are directly connected, reducing signal loss and increasing impedance. Additionally, the wire bonding process can be eliminated. In the case of FR4 rigid printed circuit boards, the same effect requires embedded MEMS and ASICs, thus increasing substrate cost is unavoidable. However, by simply expanding the etched area, substrate cost can be reduced while applying the effects of embedded MEMS and ASICs.

[0262] like Figure 38 As shown, the housing 170 is attached to the second substrate 120, or as... Figure 39 As shown, a half-etch is performed on the second substrate 120 to form the mounting portion 128; and instead of the bonding housing 170, as... Figure 53 and Figure 54 As shown, the cover 170 can be mounted on the first substrate 110 instead of the second substrate 120. In this case, the cover 170 can be surface-mounted (SMT) onto the electrode pads (copper pads) of the 2-Metal COF of the first substrate 110. The cover 170 is located on the outer periphery of the second substrate 120, so its position can be guided and fixed. After the cover 170 is placed, it can be bonded using solder 201.

[0263] Compared to the case where the housing 170 is bonded to the second substrate 120 via half-etching, the overlap length of the housing 170 and the second substrate 120 can be increased. For example, in the case of half-etching, it is 50 μm, while... Figure 53 and Figure 54 In some embodiments, it can be as long as 100 μm. This increases the adhesion area of ​​the solder 201 to improve hermetic shielding, thereby mitigating SNR sensitivity changes or performance degradation caused by air leakage.

[0264] like Figure 56 As shown, flip-chip bonding can be used to directly bond the signal processing element 140 to the first substrate 110. In this case, flip-chip bonding can be applied to the signal processing element 140. Flip-chip bonding can also be applied to the signal processing element 140 when full or partial etching is applied to the metal plate serving as the second substrate 120. Volume expansion can be achieved through etching of the metal plate, which can improve the signal-to-noise ratio (SNR).

[0265] When flip-chip bonding is applied to signal processing element 140, such as Figure 55As shown, the wire bonding lines 203 used to connect the signal processing element 140 and the first substrate 110 to the wire can be removed, and the wire bonding pad area 202 of the first substrate 110 used for wire bonding can also be removed. Since the signal processing element 140 is in direct contact with the first substrate 110 via flip-chip bonding, signal loss can be reduced and impedance can be improved.

[0266] In addition, the strikethrough line join pad area 202 can reduce the substrate size, and thus the overall package size can be reduced.

[0267] In the case of FR4 rigid printed circuit boards, embedded signal processing elements (ASICs) are required to achieve the same effect, so an increase in substrate cost is inevitable. However, by etching the second substrate 120 and flip-chip bonding the signal processing elements 140, the substrate cost can be significantly reduced while applying the effect of embedded ASICs.

[0268] Figure 57 The upper part shows according to Figure 55 The embodiments of the wire connection or circuit connection; and the lower part shows the wire connection or circuit connection according to Figure 56 The embodiments refer to wire connections or circuit connections. Like 211, the number of wire connections can be reduced from 11 to 3. In Figure 55 In this embodiment, a total of 11 lines are required: line 205 connecting the MEMS structure 130 and the signal processing element 140; line 204 connecting the capacitor 150 and the signal processing element 140; and line 203 connecting the signal processing element 140 and the substrate 110. However, for Figure 56 In this embodiment, by directly contacting the capacitor 150 and the signal processing element 140 to the first substrate 110 without wire bonding, only three lines 205 are needed to connect the capacitor 150 and the signal processing element 140, thereby reducing wire bonding. Here, the first substrate 110 may include a thin-film fine-pitch flexible substrate. The removed lines can be connected by circuitry, such as 212 (second substrate 120 and first substrate 110) and 213 (upper layer circuitry of the first substrate 110). Furthermore, by removing wire bonding, the wire bonding pads of the first substrate 110 can be eliminated, thereby reducing the size of the MEMS microphone substrate and also reducing the overall package size.

[0269] Furthermore, since the wiring freedom is ensured by applying direct bonding, the layer board circuit of the first substrate 110, such as 214 (the layer board circuit of the first substrate 110), can be simplified. As a result, the process advantage is that it is not necessary to apply solder resist to the layer.

[0270] Because the wire bonding pads are removed, free space 220 is ensured in the lower substrate area, thereby allowing for a reduction in substrate length and package size. For example, the length of the bottom PCB can be reduced by 0.13 mm, and the package size can be reduced from 3 mm × 2 mm to 2.87 mm × 2 mm.

[0271] In addition, such as Figure 58 and Figure 59 As shown, the wire bonding length of the MEMS structure 130 can be reduced by applying the wire bonding direction to the side rather than the direction of the signal processing element 140. The reduced wire bonding length can be achieved using circuitry within the substrate (such as... Figure 59 This can be achieved using circuitry (as described in the original text), which reduces costs. In this case, the wire bonding pads are also removed, thus ensuring free space 220 in the lower substrate area. As a result, the substrate length can be reduced and the package size can be reduced. For example, the length of the lower side of the PCB can be reduced by 0.13 mm, and the package size can be reduced from 3 mm × 2 mm to 2.87 mm × 2 mm.

[0272] Those skilled in the art related to this embodiment will understand that the above description can be implemented in modified forms without departing from the essential characteristics. Therefore, the disclosed methods should be considered from an interpretative rather than restrictive perspective. The scope of the invention is indicated in the claims rather than the foregoing description, and all differences within the equivalent scope should be interpreted as included within the invention.

Claims

1. A MEMS microphone, comprising: First substrate; A second substrate is stacked on the first substrate; The MEMS structure is disposed on the second substrate; as well as A capacitor, spaced apart from the MEMS structure and disposed on the second substrate. The second substrate includes one or more holes, and The capacitor is electrically connected to the first substrate via a wire passing through a hole in the second substrate.

2. The MEMS microphone according to claim 1, in, The holes in the second substrate include: A first hole, through which a wire connecting the capacitor and the first substrate passes; and The second hole corresponds to the lower part of the MEMS structure.

3. The MEMS microphone according to claim 1, in, The hole in the second substrate is formed at a predetermined distance or more from the outer periphery of the second substrate.

4. The MEMS microphone according to claim 1, comprising: A conductive adhesive layer between the first substrate and the second substrate, and The conductive adhesive layer includes holes that overlap with the holes in the second substrate.

5. The MEMS microphone according to claim 4, in, The area of ​​the holes in the conductive adhesive layer is larger than the area of ​​the holes in the second substrate.

6. The MEMS microphone according to claim 1, in, The first substrate includes a connection pad disposed at a position corresponding to the lower portion of the hole in the second substrate.

7. The MEMS microphone according to claim 1, comprising: An ASIC module is disposed on the second substrate and spaced apart from the MEMS structure. The ASIC module is electrically connected to the first substrate via a wire passing through the hole in the second substrate.

8. The MEMS microphone according to claim 7, in, The ASIC module is electrically connected to the MEMS structure and the capacitor via wires.

9. The MEMS microphone according to claim 1, in, The first substrate is a flexible substrate, and the second substrate is a rigid substrate.

10. The MEMS microphone according to claim 1, in, The first substrate and the second substrate are joined together by thermoforming.

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