MEMS microphone

Abstract

A MEMS microphone according to the present embodiment comprises: a first substrate; a second substrate disposed on the first substrate; an adhesive layer disposed between the first substrate and the second substrate; a photo solder resist (PSR) layer disposed on the second substrate; and a MEMS structure disposed on the second substrate, wherein the PSR layer comprises an open region in which the second substrate is exposed, and the open region comprises a first edge part formed along the outer edge of the MEMS structure.

Description

MEMS microphone

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

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

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

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

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

[0006] To solve the above technical problem, the MEMS microphone according to the present embodiment comprises: a first substrate; a second substrate disposed on the first substrate; an adhesive layer disposed between the first substrate and the second substrate; a Photo Solder Resist (PSR) layer disposed on the second substrate; and a MEMS structure disposed on the second substrate, wherein the PSR layer includes an open region in which the second substrate is exposed, and the open region includes a first edge portion formed on the outer edge of the MEMS structure.

[0007] The first edge portion includes a first corner portion and a second corner portion opposite each other, and a third corner portion and a fourth corner portion connected to the first and second corner portions and opposite each other, and the first to fourth corner portions may be spaced apart from each other.

[0008] The above open region may include a second edge portion formed on the inner edge of the MEMS structure.

[0009] The second edge portion includes a first corner portion facing the first edge portion and the third edge portion of the first edge portion, a second corner portion facing the first edge portion and the fourth edge portion of the first edge portion, a third corner portion facing the second edge portion and the fourth edge portion of the first edge portion, and a fourth corner portion facing the second edge portion and the third edge portion of the first edge portion, and the first to fourth corner portions may be spaced apart from each other.

[0010] The above-mentioned first substrate and the above-mentioned second substrate include a hole penetrating them, and the MEMS structure is arranged to surround the hole, and the second edge portion of the open area includes two corner portions opposite each other, and the open area may include a first area connecting the two corner portions and the hole.

[0011] It includes a signal processing element spaced apart from the MEMS structure and disposed on the second substrate, and the open region of the PSR layer may include a third edge portion formed at the edge of the signal processing element.

[0012] The apparatus includes a housing disposed on the second substrate, wherein the housing includes a first side plate and a second side plate forming a corner portion, and the third edge portion includes a fifth corner portion formed between the first side plate of the housing and the signal processing element and a sixth corner portion formed between the second side plate of the housing and the signal processing element, and the fifth corner portion and the sixth corner portion may be spaced apart from each other.

[0013] The fifth corner portion is formed in a line shape extending along the first direction, and the distance between the fifth corner portion and the second side plate in the first direction may be 5% or more and 15% or less relative to the length of the second substrate in the first direction.

[0014] The sixth corner portion is formed in a line shape extending along a second direction perpendicular to the first direction, and the distance between the sixth corner portion and the first side plate in the second direction may be 0.2 mm or more and 0.5 mm or less.

[0015] An adhesive member may be disposed between the first edge portion and the second edge portion of the PSR layer on the second substrate.

[0016] According to the embodiments, an area acting as a dam can be formed in the PSR layer to prevent the adhesive from spreading. Additionally, an open area can be formed in the PSR layer by simply modifying the exposure data during the PSR coating process without any additional processes.

[0017] In addition, product quality can be ensured by minimizing the impact of the adhesive on adjacent parts.

[0018] In addition, it is possible to prevent overflow or spreading of the adhesive material, enabling control such as using a consistent amount of adhesive material during the product manufacturing process.

[0019] FIG. 1 is a side view illustrating the structure of a MEMS microphone according to the present embodiment.

[0020] FIG. 2 is an exploded view of a substrate unit of a MEMS microphone according to the present embodiment.

[0021] FIG. 3 is a diagram illustrating the open area of ​​the PSR according to the present embodiment.

[0022] Figure 4 is a diagram illustrating the effect according to the open area of ​​the PSR according to the present embodiment.

[0023] FIG. 5 is a side view of a MEMS microphone for explaining an adhesive member applied to a MEMS structure according to the present embodiment.

[0024] FIGS. 6 to 8 are top views of a MEMS microphone for illustrating a PSR open region according to the present embodiment.

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0026] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0027] In addition, terms used in this embodiment (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which this embodiment belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0028] Furthermore, the terms used in this embodiment are for the purpose of describing the embodiment and are not intended to limit the invention.

[0029] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0030] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the present embodiment. These terms are used merely to distinguish the components from other components and are not intended to limit the essence, order, or sequence of the components.

[0031] And, where it is stated that a component is 'connected', 'combined', or 'connected' to another component, this may include not only cases where the component is directly 'connected', 'combined', or 'connected' to the other component, but also cases where it is 'connected', 'combined', or 'connected' due to another component located between the component and the other component.

[0032] Furthermore, when described as being formed or placed "above" or "below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above" or "below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0033]

[0034] FIG. 1 is a side view illustrating the structure of a MEMS microphone according to the present embodiment, FIG. 2 is an exploded view of a substrate unit of a MEMS microphone according to the present embodiment, FIG. 3 is a drawing for explaining the open area of ​​a PSR according to the present embodiment, FIG. 4 is a drawing for explaining the effect according to the open area of ​​a PSR according to the present embodiment, FIG. 5 is a side view of a MEMS microphone for explaining an adhesive member applied to a MEMS structure according to the present embodiment, and FIG. 6 to 8 are top views of a MEMS microphone for explaining the open area of ​​a PSR according to the present embodiment.

[0035] Referring to FIG. 1, the MEMS microphone according to the present embodiment may include a first substrate (100), a second substrate (200), a MEMS structure (300), a housing (400), a signal processing element (500), and at least one capacitor (600).

[0036] The first substrate (100) is placed at the bottom of the MEMS microphone, has a plate shape, and can be electrically connected to the outside. The second substrate (200) is placed on the upper part of the first substrate (100), so that the first substrate (100) and the second substrate (200) can form a single substrate unit, and the substrate unit can form an internal space together with the housing (400).

[0037] The first substrate (100) is a flexible substrate and may be a Chip on Film (COF) substrate or a flexible printed circuit board (FPCB). A Chip on Film (COF) substrate is a substrate formed by forming a circuit on a base film or mounting a component such as a chip, and has a film shape, so it is a substrate with a thickness that is considerably thinner than other substrates. By using a COF substrate as the substrate for a MEMS microphone, the thickness can be reduced compared to the case where a conventional rigid substrate is used.

[0038] The first substrate (100) is a COF substrate and may include a 2-metal COF substrate. The 2-metal COF may be formed in a structure in which a metal layer is laminated on the upper and lower surfaces of a base film so as to form a circuit or mount a device on both sides of a base film.

[0039] A flexible printed circuit board (FPCB) is a flexible circuit board that is also flexible and has a thinner thickness compared to a standard PCB board, so the thickness can be reduced by using a flexible printed circuit board as a substrate for a MEMS microphone. Other types of flexible substrates may be included. For example, the first substrate (100) may be an LCP (Liquid Crystal Polymer)-based FPCB, a PI (Polyimide)-based FPCB, or a PI-based COF, and the type of the first substrate (100) is not limited to the examples described above.

[0040] A hole may be formed in the first substrate (100) at a position facing the lower part of the MEMS structure (300). The cross-sectional area of ​​the hole may be circular, but is not limited thereto. Here, the hole may be an acoustic hole.

[0041] The first substrate (100) may include a first pad (110). The first substrate (100) may have a first front pad formed on its front surface to be electrically connected to a second pad of the second substrate (200) and a first rear pad formed to be electrically connected to a rear external configuration. That is, the first pad (110) may include a first front pad and a first rear pad.

[0042] A plurality of first front pads and a first connection circuit connecting them may be formed on the front surface of the first substrate (100). A signal processing element and a capacitor may be electrically connected to the plurality of first front pads and the first connection circuit. A plurality of first rear pads and a second connection circuit may be formed on the rear surface of the first substrate (100).

[0043] The first substrate (100) may include via holes. In this case, the first substrate (100) may connect the first front pad and the first rear pad formed on both sides through a metal layer (e.g., via) formed in the via holes. Some of the first pads (110) may be exposed through the cavity (210) of the second substrate (200).

[0044]

[0045] The second substrate (200) is a substrate having a plate shape that is stacked to be placed on top of the first substrate (100). The second substrate (200) may include a rigid substrate, and may include, for example, a printed circuit board (PCB), a semiconductor substrate, or a ceramic substrate, a metal plate, etc. The second substrate (200) may be composed of a single layer or may be formed by stacking a plurality of substrates.

[0046] The second substrate (200) may include via holes. In this case, the second substrate (200) may connect circuits or components formed on both sides through a metal layer (e.g., via) formed in the via holes. Here, the via holes may be micro via holes and may be configured with a size of 25 μm or less.

[0047] The second substrate (200) may include an acoustic hole. The cross-sectional area of ​​the acoustic hole may be circular, but is not limited thereto. The hole formed in the second substrate (200) may be arranged to communicate with the hole formed in the first substrate (100), and a MEMS structure (300) may be arranged on the upper part of the hole communicating with the first substrate (100) and the second substrate (200).

[0048] The second substrate (200) can be electrically connected to the first substrate (100). The second substrate (200) may include a plurality of pads for electrically connecting to the first substrate (100).

[0049] The second substrate (200) may include a second pad. The second pad may include a plurality of second front pads formed on the front surface of the second substrate (200) and a plurality of second rear pads formed on the rear surface of the second substrate (200). That is, the second pad may include a second front pad and a second rear pad. The second front pad may be electrically connected to a signal processing element (500) and a capacitor (600), and the second rear pad may be electrically connected to the first front pad of the first substrate (100). The second rear pad of the second substrate (200) may be formed to have the same or similar shape and size as the first front pad of the first substrate (100), and may be electrically connected by being stacked so that at least a portion overlaps vertically.

[0050] The second substrate (200) may include one or more cavities (210). The second substrate (200) is placed on top of the first substrate (100), and the first substrate (100) may be exposed to the top of the second substrate (200) through the cavity (210) of the second substrate (200). The first substrate (100) may be exposed to the top of the second substrate (200) by having a first pad (110), etc., placed in the space where the cavity (210) of the second substrate (200) is formed. In this case, since the upper surface of the first substrate (100) is placed on the lower surface of the second substrate (200), the first front pad (110), etc. formed on the upper surface of the first substrate (100) may be exposed to the top of the second substrate (200) through the cavity (210) of the second substrate (200). The first pad (110) of the first substrate (100) can be electrically connected to a signal processing element (500) and a capacitor (600) through a cavity (210) formed in the second substrate (200).

[0051] The second substrate (200) can be electrically connected to the signal processing element (500) and the capacitor (600). The second substrate (200) may include a plurality of pads, a plurality of connection circuits, and a plurality of vias for electrically connecting to the signal processing element (500) and the capacitor (600). The plurality of pads may overlap and contact the vias perpendicularly, or may contact an external substrate or element. The connection circuits may connect the second pads disposed on the same layer. The vias may be formed in via holes penetrating a base film or an insulating layer.

[0052] The second substrate (200) is laminated on top of the first substrate (100) so that the first substrate (100) and the second substrate (200) can form a single substrate unit. An adhesive layer (700) is disposed between the lower part of the second substrate (200) and the upper part of the first substrate (100) to bond the first substrate (100) and the second substrate (200). The adhesive layer (700) may have a shape and size corresponding to the shape and size of the first substrate (100) or the second substrate (200) as a means of bonding the first substrate (100) and the second substrate (200). The adhesive layer (700) may be made of a conductive material, but is not limited thereto and may be made of a non-conductive material.

[0053] As the first substrate (100) and the second substrate (200) form a substrate unit, the second substrate (200) not only complements the rigidity of the first substrate (100) but also simplifies the pad design structure of the second substrate (200), and since the first substrate (100) is a flexible substrate that enables fine pitch, it is implemented to have a thinner thickness and increased fine pitch realization compared to a substrate unit using a rigid substrate where the existing pad design is performed, thereby having the effect of high freedom in circuit design.

[0054] A housing (400), a MEMS structure (300), a signal processing element (500), and a capacitor (600) may be disposed on the second substrate (200). The capacitor (600) may be optionally disposed on the second substrate (200) as needed.

[0055] A housing (400) is a means for being placed on top of a second substrate (200) and forming a receiving space inside. The housing (400) may be formed in a cover shape with an open bottom surface, and the receiving space may be formed by the bottom surface of the housing (400) being joined to the top surface of the second substrate (200). The housing (400) and the second substrate (200) may be joined by solder being placed on top of the second substrate (200) and adhering to the bottom surface of the housing (400). Noise conditions such as SNR, PSR, and PSRR may be determined according to the size (Back Volume) of the receiving space formed inside the housing (400).

[0056] The housing (400) may be made of nickel silver or stainless steel (SUS). Nickel silver is a material containing 15-30% zinc and 10-20% nickel in copper, and allows for solder bonding without plating in its raw material state. Applying plating to the seating area of ​​the housing (400) can improve the solder bond adhesion. Ni+Au plating can be applied. Both electroless and electrolytic plating processes can be applied. Although stainless steel (SUS) contains Ni, the solder bond adhesion may decrease if plating is not performed. Therefore, plating can be applied. Unlike nickel silver, the plating adhesion on the surface of stainless steel may decrease when electroless plating is applied, so plating can be performed using an electrolytic plating process.

[0057] The MEMS structure (300) may be placed within a receiving space formed by a housing (400). The MEMS structure (300) may include a body (310), a backplate (330), and a diaphragm (320). The MEMS structure (300) may be placed on top of a second substrate (200), and the lower part of the MEMS structure (300) may be placed at a position adjacent to an acoustic hole (10) of the second substrate (200).

[0058] The body (310) is a means for forming a partition wall that surrounds the acoustic hole (10) formed in the second substrate (200). The body (310) can be coupled to the second substrate (200) so as to be electrically connected to the first substrate (100) through the second substrate (200). Additionally, an acoustic hole (360) communicating with the acoustic hole (10) can be formed in the body (310). The body (310) can be electrically connected to the second substrate (200).

[0059] An acoustic hole (360) may be formed in the body (310). When the body (310) is coupled to the second substrate (200), the acoustic hole (10) formed in the first substrate (100) and the second substrate (200) and the acoustic hole (360) of the body (310) may be arranged to communicate with each other, and thus, sound from the outside may be designed to flow in through the acoustic hole (10).

[0060] The backplate (330) and the diaphragm (320) can be placed in the acoustic hole (10) formed in the body (310). The diaphragm (320) can vibrate due to the sound pressure of the sound when sound is introduced from the outside through the acoustic hole (10), and the backplate (330) can sense the acoustic signal by measuring the capacitance according to the vibration of the diaphragm (320). Although the backplate is shown as being located above the diaphragm (320) in the drawing, the diaphragm (320) may also be located above the backplate.

[0061] One or more body pads for electrical connection may be formed on the upper surface of the body (310). The body pads may be electrically connected to the backplate (330) and the diaphragm (320), and may be electrically connected to the signal processing element (500), which will be described later, via a wire. However, the connection method is merely an example, and as needed, the body pads may be placed in a form directly mounted on the pads of the second substrate (200) and electrically connected to the signal processing element (500) through a connection circuit. As the shape and material of the body pads are known technologies for electrical connection, a description thereof is omitted.

[0062] The signal processing element (500) is electrically connected to the MEMS structure (300) and can process electrical signals sensed from the MEMS structure (300). The MEMS structure (300) and the signal processing element (500) can be electrically connected through a body pad. For example, the MEMS structure (300) and the signal processing element (500) can be connected by a wire through wire bonding. As another example, the MEMS structure (300) and the signal processing element (500) can be electrically connected through a connection circuit of the second substrate (200) while mounted on the second substrate (200) in a flip-chip form. When the MEMS structure (300) and the signal processing element (500) are wire-bonded, a signal pad may be placed on the signal processing element (500) to be connected to the body pad of the MEMS structure (300) through wire bonding.

[0063] The signal processing element (500) can amplify a signal sensed from the MEMS structure (300). Here, the signal processing element (500) may include an Application-Specific Integrated Circuit (ASIC), but is not limited thereto. The signal processing element (500) may be formed as a single module or may be formed in the form of a chip. The signal processing element (500) may include an ASIC and an En-cap that coats the ASIC.

[0064] A signal processing element (500) may be placed on a second substrate (200). The signal processing element (500) may be electrically connected to a first substrate (100) through the second substrate (200). The signal processing element (500) may be placed on the second substrate (200) spaced apart from the MEMS structure (300). The signal processing element (500) may be placed in a receiving space formed inside a housing (400) spaced apart from the MEMS structure (300) and may receive a signal from the MEMS structure (300). Since signal transmission between the MEMS structure (300) and the signal processing element (500) takes place in the receiving space formed by the housing (400), external interference is reduced, and thereby noise can be reduced.

[0065] The signal processing element (500) can be electrically connected to the MEMS structure (300) and the first substrate (100). The signal processing element (500) can be electrically connected to the MEMS structure (300). The signal processing element (500) can be electrically connected to a body pad formed on the body (310) of the MEMS structure (300) by having a signal pad disposed on its upper surface. The signal pad of the signal processing element (500) and the body pad of the MEMS structure (300) can be electrically connected through wire bonding, thereby allowing the signal processing element (500) and the MEMS structure (300) to be electrically connected.

[0066] The signal processing element (500) can be electrically connected to the first substrate (100) by being electrically connected to the second substrate (200). The signal processing element (500) can be electrically connected to the second substrate (200) through wire bonding or electrically connected by being mounted on the second substrate (200) in the form of a flip chip. Since a plurality of pads are arranged on the second substrate (200), the signal processing element (500) can be electrically connected to the pads of the second substrate (200) through wire bonding or electrically connected by being mounted on the pads of the second substrate (200) in the form of a flip chip, and can be electrically connected to the first substrate (100) through the pads of the second substrate (200). The signal processed by the signal processing element (500) can be transmitted to an external location requiring the signal through one or more of the pads, connection circuits, and vias formed on the second substrate (200) and through the pads formed on the first substrate (100).

[0067] A capacitor (600) may be optionally placed on the upper part of the second substrate (200) as needed. When the capacitor (600) is placed, the performance of PSRR, which is RF-related noise, can be improved, and the performance of PSR (Power Supply Rejection), which is power-related noise, can be improved. That is, through the capacitor (600), noise-related performance such as SNR (Signal-to-Noise Ratio), PSRR (Power Supply Rejection Ratio), and PSR can be improved. The capacitor (600) can be electrically connected to the signal processing element (500). As a result, the capacitor (600) can remove noise during the process of processing signals in the signal processing element (500).

[0068] The capacitor (600) is positioned on the upper part of the second substrate (200) and can be electrically connected to the signal processing element (500) and can be electrically connected to the first substrate (100) through the second substrate (200). The capacitor (600) can be electrically connected to the signal processing element (500) and the first substrate (100) via wires. The capacitor (600) can be electrically connected to the signal pad of the signal processing element (500) via wire bonding and can be electrically connected to the pad of the second substrate (200) via wire bonding.

[0069] However, the capacitor (600) can be electrically connected to the first substrate (100) not only by bonding via wires but also by mounting it on the second substrate (200) or the signal processing element (500) in a flip-chip form. For example, the capacitor (600) can be mounted on a second pad formed on the upper part of the second substrate (200). The capacitor (600) can be mounted on a second front pad formed on the front surface of the second substrate (200). As the fine-pitch circuit implementation of the second substrate (200) becomes possible, the effect of securing mounting space for the capacitor is achieved.

[0070] According to another embodiment, the capacitor (600) may be placed on the upper portion of the first substrate (100). The capacitor (600) may be placed on the first pad (110) of the first substrate (100) which is exposed through the cavity (210) of the second substrate (200). The capacitor (600) may be soldered to the first pad (110) of the first substrate (100).

[0071]

[0072] The MEMS microphone according to the present embodiment may include a Photo Solder Resist (PSR) layer (800) disposed on a second substrate (200). The PSR layer (800) is formed by applying ink used to protect and form circuits on the substrate, and serves to protect circuits formed on the surface of the substrate to prevent corrosion or short circuits, and allows plating to be performed only on the necessary parts during the soldering process. The PSR layer (800) may be referred to as either an ink layer or a surface protection layer.

[0073] An adhesive member (900) is used in the process of mounting components such as a MEMS structure (300) and a signal processing element (500) placed on a second substrate (200). At this time, the adhesive member (900) may be silicone, epoxy, etc. Due to the viscosity, flowability, etc. of the material forming the adhesive member (900), even if an appropriate amount is applied on the second substrate (200), a problem arises in which interference is caused to adjacent components.

[0074] The present invention is intended to solve these problems by selectively forming an open area (810) in the PSR layer (800) to act as a dam that prevents the adhesive material (900) from spreading. An open area can be formed in the PSR layer by simply modifying the exposure data during the PSR coating process without additional processes, and product quality can be ensured by minimizing the impact of the adhesive material on adjacent parts. In addition, since overflow or spreading of the adhesive material can be prevented, control such as using a certain amount of adhesive material during the product process is possible.

[0075] The process of forming the PSR layer (800) first removes oxides, contaminants, and oil from the surface of the second substrate (200) to ensure that the PSR adheres well. Subsequently, the PSR is applied using methods such as screen printing, spray coating, and roller coating. To form open areas where the PSR is not applied, an exposure and development process is performed. A UV light source is selectively irradiated using a photomask on areas where the PSR is not required. At this time, the PSR in the exposed areas is not cured, and only the unexposed areas are cured.

[0076] Subsequently, the uncured PSR is removed using a developer, and UV curing is performed to enhance the durability of the PSR layer. Unlike the process described above, depending on the characteristics of the photosolder resist, the PSR in the exposed areas may cure, while the unexposed areas may not. The description of the process for forming the PSR layer is merely illustrative and is not necessarily limited thereto.

[0077] For reference, FIG. 4(a) illustrates the spreading phenomenon (e) of the adhesive member when the open area (810) of the PSR layer (800) is not formed, and FIG. 4(b) illustrates the state (f) in which the adhesive member does not spread to the left through the open area (810) formed in the PSR layer (800).

[0078]

[0079] The PSR layer (800) according to the present embodiment may include an open area (810) where the second substrate (200) is exposed. The open area (810) is an area where the PSR is not applied. Referring to FIG. 3, the thickness (m) of the PSR layer (800) may be approximately 10 µm or more and approximately 50 µm or less, and preferably approximately 20 µm or more and approximately 25 µm or less. If the thickness (m) of the PSR layer (800) satisfies the above conditions, the dam effect preventing the spreading of the adhesive member can be enhanced, and the internal volume of the MEMS microphone can be appropriately secured to improve SNR performance. If it is below the lower limit of the above conditions, the effect of preventing the spreading of the adhesive member may be negligible even if a dam is formed. If it exceeds the upper limit of the above conditions, there is a problem in that the internal volume of the MEMS microphone decreases, thereby degrading SNR performance.

[0080] The total thickness (l) of the first substrate (100), adhesive layer (700), second substrate (200), and PSR layer (800) can satisfy approximately 175 µm or more and approximately 200 µm or less. The thickness (m) of the PSR layer (800) can satisfy approximately 4% or more and 28% or less relative to the total thickness (l) of the first substrate (100), adhesive layer (700), second substrate (200), and PSR layer (800). If the thickness (m) of the PSR layer (800) satisfies the above conditions, the dam effect preventing the spreading of the adhesive material can be enhanced, and the internal volume of the MEMS microphone can be properly secured to improve SNR performance. If it is below the lower limit of the above conditions, the effect of preventing the spreading of the adhesive material may be negligible even if a dam is formed. If the upper limit of the above conditions is exceeded, there is a problem in that the internal volume of the MEMS microphone decreases, causing the SNR performance to deteriorate.

[0081]

[0082] Looking at the top view of the second substrate (200) of the MEMS microphone through FIGS. 6 to 8, the outermost edge of the second substrate (200) may include an area (220) where a housing (400) is disposed. The right side of the second substrate (200) may include an area (230) where a MEMS structure (300) is disposed, the lower left side may include an area (240) where a signal processing element (500) is disposed, and the upper right side may include an area (250) where a cavity (210) is formed and a capacitor (600) is disposed.

[0083] As shown in FIG. 6, when the capacitor (600) is placed on the second substrate (200), the capacitor (600) can be wired to the first pad (110) of the first substrate (100) exposed through the cavity (210). Also, as shown in FIG. 7, when the capacitor (600) is placed on the first substrate (100), the capacitor (600) can be directly soldered to the first substrate (100). Additionally, as shown in FIG. 8, the capacitor (600) can be placed on a pad plated on the second substrate (200). The fact that the shape of the area (250) where the capacitor (600) is placed and the cavity (210) in FIGS. 6 to 8 are different is intended to explain that the capacitor (600) can be placed in various ways, and it is obvious that in each embodiment, the placement method of the capacitor (600) and the shape and size of the cavity (210) can be varied and applied.

[0084]

[0085] The MEMS structure (300) may be arranged to surround an acoustic hole (10) penetrating the first substrate (100) and the second substrate (200). The body (310) of the MEMS structure (300) may form a partition based on the acoustic hole (10) formed in the second substrate (200). The area (230) on the second substrate (200) where the MEMS structure (300) is placed may be formed as a square border, a square ring, a square frame, or a square border. Alternatively, the area on the second substrate (200) where the structure is placed may be modified into various shapes surrounding the acoustic hole (10), but below, the description will be based on the square border shape.

[0086] An adhesive member (900) may be placed in the area (230) where the MEMS structure (300) is placed and in the area (240) where the signal processing element (500) is placed. An adhesive member (900) may be placed between the MEMS structure (300) and the second substrate (200). The MEMS structure (300) may be fixedly coupled to the second substrate (200) through the adhesive member (900). An adhesive member (900) may be placed between the signal processing element (500) and the second substrate (200). The signal processing element (500) may be fixedly coupled to the second substrate (200) through the adhesive member (900).

[0087] Referring to FIG. 5, the total thickness (L) of the first substrate (100), adhesive layer (700), second substrate (200), and PSR layer (800) in the third direction (z-axis direction), which is the stacking direction of the first substrate (100), adhesive layer (700), second substrate (200), and PSR layer (800), may be about 175 µm to about 200 µm. The length (q) of the MEMS structure (300) in the third direction (z-axis direction) may be about 405 µm to about 490 µm. The length (o) of the adhesive member (900) in the third direction (z-axis direction) may be about 100 µm to about 300 µm. The length (p) of the adhesive member (900) from the outer surface of the MEMS structure (300) in the first direction (x-axis direction) perpendicular to the third direction may be about 170 µm to about 190 µm. The length (n) of the acoustic hole (10) in the first direction may be about 1 mm to about 2 mm. The thickness and length of each component described above are merely exemplary and are not specifically limited thereto.

[0088]

[0089] The open region (810) of the PSR layer (800) described below through FIGS. 6 to 8 is not composed solely of the shape shown in each figure, but can be composed of a single embodiment in which various shapes included in the open region (810) of the PSR layer (800) are individually selected.

[0090] For example, it is obvious that variations are possible, such as a first edge portion (811) formed by a single line and a second edge portion (812) including a plurality of spaced-apart corner portions as one embodiment, or a first edge portion (811) formed by a plurality of spaced-apart corner portions and a second edge portion (812) formed by a single line as one embodiment. For convenience of explanation, the following description will be based on the contents illustrated in FIGS. 6 to 8.

[0091]

[0092] Referring to FIGS. 6 and 7, the open region (810) of the PSR layer (800) may include a first edge portion (811) formed on the outer edge of the MEMS structure (300) and a second edge portion (812) formed on the inner edge of the MEMS structure (300). The first edge portion (811) may be formed along the outer edge of the region (230) where the MEMS structure (300) is placed on the second substrate (200). The second edge portion (812) may be formed along the inner edge of the region (230) where the MEMS structure (300) is placed on the second substrate (200). The first edge portion (811) and the second edge portion (812) may be formed as lines to have a square ring shape. The first edge portion (811) and the second edge portion (812) may vary depending on the shape of the MEMS structure (300).

[0093] An adhesive member (900) may be placed between the first edge portion (811) and the second edge portion (812). When the adhesive member (900) is placed in the area (230) where the MEMS structure (300) is placed, the first edge portion (811) acts as a dam, so the adhesive member (900) can be prevented from spreading outward, and the second edge portion (812) acts as a dam, so the adhesive member (900) can be prevented from spreading inward.

[0094]

[0095] Referring to FIG. 7, the open area (810) of the PSR layer (800) may include a first area (815) connecting two opposite corners of the second edge portion (812) and the acoustic hole (10). The first area (815) may be formed along the outer edge of the acoustic hole (10). The first area (815) may be formed in an area surrounding the acoustic hole (10). The first area (815) may be formed in an inner area of ​​the second edge portion (812).

[0096] The first region (815) can prevent the adhesive member (900) placed in the region (230) where the MEMS structure (300) is placed on the second substrate (200) from spreading beyond the second edge portion (812) to the range adjacent to the acoustic hole (10) or into the acoustic hole (10).

[0097]

[0098] Referring to FIG. 8, the first edge portion (811) may include a first edge portion (811a) and a second edge portion (811c) opposite each other, and a third edge portion (811d) and a fourth edge portion (811b) opposite each other and connected to the first edge portion (811a) and the second edge portion (811c). The first to fourth edge portions (811a, 811c, 811d, 811b) may be formed in a straight line shape.

[0099] The first to fourth corner sections (811a, 811c, 811d, 811b) may be spaced apart from each other. The shortest distance (t) between the first corner section (811a) and a virtual line extending the fourth corner section (811b) in the second direction (y-axis direction) is approximately 0.15 mm, and the error range may be ±5% or less. The shortest distance (u) between the fourth corner section (811b) and a virtual line extending the first corner section (811a) in the first direction (x-axis direction) is approximately 0.15 mm, and the error range may be ±5% or less.

[0100] If the first edge portion (811) is formed as a single line, the PSR coating area between the first edge portion (811) and the area (220) where the housing (400) is placed on the second substrate (200) becomes narrow, which causes a problem where the PSR peels off during processes such as cleaning and plating after PSR coating. Therefore, if the first edge portion (811) is not formed as a single line but is formed as first to fourth corner portions (811a, 811c, 811d, 811b) that are spaced apart from each other, a sufficient PSR coating area can be secured in the spaced-apart areas of the first to fourth corner portions (811a, 811c, 811d, 811b), thereby preventing the PSR peeling phenomenon.

[0101] The third corner portion (811d) of the first edge portion (811) may face the cavity (210) of the second substrate (200). In order to sufficiently secure the area where PSR is applied between the third corner portion (811d) of the first edge portion (811) and the cavity (210), the area facing the third corner portion (811d) of the cavity (210) may be reduced. Through this, the phenomenon of the PSR applied between the third corner portion (811d) of the first edge portion (811) and the cavity (210) peeling off can be prevented.

[0102]

[0103] The second edge portion (812) may include a first corner portion (812a) facing the first corner portion (811a) and the third corner portion (811d) of the first edge portion (811), a second corner portion (812b) facing the first corner portion (811a) and the fourth corner portion (811b) of the first edge portion (811), a third corner portion (812c) facing the second corner portion (811c) and the fourth corner portion (811b) of the first edge portion (811), and a fourth corner portion (812d) facing the second corner portion (811c) and the third corner portion (811d) of the first edge portion (811). The first to fourth corner portions (812a, 812b, 812c, 812d) may be formed in a shape where two straight lines are connected vertically. The first to fourth corner portions (812a, 812b, 812c, 812d) may be formed in the same shape. The first to fourth corner portions (812a, 812b, 812c, 812d) may be formed in different shapes.

[0104] The first to fourth corner sections (812a, 812b, 812c, 812d) may be spaced apart from each other. The shortest distance (v) between the first corner section (812a) and the second corner section (812b) that are adjacent in the first direction (x-axis direction) is approximately 0.245 mm, and the error range may be ±5% or less. The shortest distance (w) between the second corner section (812b) and the third corner section (812c) that are adjacent in the second direction (y-axis direction) is approximately 0.65 mm, and the error range may be ±5% or less.

[0105] If the second edge portion (812) is formed as a single line, the area of ​​PSR application between the second edge portion (812) and the area (230) where the MEMS structure (300) is placed on the second substrate (200) or between the second edge portion (812) and the acoustic hole (10) becomes narrow, which causes a problem where the PSR peels off during processes such as cleaning and plating after PSR application. Therefore, if the second edge portion (812) is not formed as a single line but is formed as first to fourth corner portions (812a, 812b, 812c, 812d) that are spaced apart from each other, the PSR application area can be sufficiently secured in the spaced-apart areas of the first to fourth corner portions (812a, 812b, 812c, 812d), thus preventing the PSR peeling phenomenon.

[0106]

[0107] The open area (810) of the PSR layer (800) may include a third edge portion (813, 814) formed on the outer edge of the signal processing element (500). The area (240) on which the signal processing element (500) is placed on the second substrate (200) may be formed in a rectangular shape. The third edge portion (813, 814) may be formed along any one of the four corners of the area (240) on which the signal processing element (500) is placed on the second substrate (200). The third edge portion (813, 814) may include at least one corner portion formed along at least one corner of the area (240) on which the signal processing element (500) is placed on the second substrate (200). The third edge portion (813, 814) may include four corner portions spaced apart from each other and formed along the four corners of the area (240) where the signal processing element (500) is disposed on the second substrate (200).

[0108] A housing (400) disposed on a second substrate (200) may include a first side plate and a second side plate forming a corner portion. Referring to FIGS. 6 to 8, the second substrate (200) may include an area (201) where the first side plate of the housing (400) is disposed and an area (202) where the second side plate of the housing is disposed. The third edge portion (813, 814) of the open area (810) of the PSR layer (800) may include a fifth corner portion (813) formed between the first side plate of the housing (400) and the signal processing element (500), and a sixth corner portion (814) formed between the second side plate of the housing (400) and the signal processing element (500). The fifth corner portion (813) and the sixth corner portion (814) may be formed in a straight line shape.

[0109] The fifth corner section (813) and the sixth corner section (814) may be spaced apart from each other. A spaced-out area (aa) may be formed between the fifth corner section (813) and the sixth corner section (814). The spaced-out area (aa) may have a shape in which two straight lines are perpendicular. The spaced-out area (aa) may overlap with the fifth corner section (813) in the first direction (x-axis direction) and overlap with the sixth corner section (814) in the second direction (y-axis direction). The fifth corner section (813) and the sixth corner section (814) may not overlap in the first direction (x-axis direction) and may not overlap in the second direction (y-axis direction).

[0110] When the fifth corner portion (813) and the sixth corner portion (814) are formed on the PSR layer (800), the area where the PSR is applied between the fifth corner portion (813) and the first side plate of the housing (400) and between the sixth corner portion (814) and the second side plate of the housing is narrowed, and as a result, there is a problem in that the PSR peeling phenomenon occurs. Therefore, by forming a gap area (aa) between the fifth corner portion (813) and the sixth corner portion (814), the area where the PSR is applied is sufficiently secured and the PSR peeling phenomenon can be prevented.

[0111] The shortest distance (s) between the fifth corner portion (813) and the second side plate of the housing (400) or the distance (s) between the fifth corner portion (813) and the second side plate of the housing (400) in the first direction (x-axis direction) may be about 0.2 mm or more and about 0.5 mm or less, and may satisfy an error range of ±5% or less. The distance (s) between the fifth corner portion (813) and the second side plate of the housing (400) in the first direction (x-axis direction) may satisfy about 5% or more and about 15% or less relative to the length of the second substrate (200) in the first direction (x-axis direction).

[0112] The shortest distance (r) between the sixth corner portion (814) and the first side plate of the housing (400) or the distance (r) between the sixth corner portion (814) and the first side plate of the housing (400) in the second direction (y-axis direction) can be about 0.2 mm or more and about 0.5 mm or less, and can satisfy an error range of ±5% or less. The distance (r) between the sixth corner portion (814) and the first side plate of the housing (400) in the second direction (y-axis direction) can satisfy about 5% or more and about 15% or less relative to the length of the second substrate (200) in the second direction (y-axis direction).

[0113] Although not illustrated in FIGS. 6 to 8, the third edge portion (813, 814) may be formed between the area (240) where the signal processing element (500) is placed on the second substrate (200) and the cavity (210), or between the area (240) where the signal processing element (500) is placed on the second substrate (200) and the MEMS structure (300). Alternatively, the third edge portion (813, 814) may be formed in a square ring shape along the entire edge of the area (240) where the signal processing element (500) is placed. The third edge portion (813, 814) may be modified into various shapes depending on the shape of the area (240) where the signal processing element (500) is placed or the shape of the signal processing element (500).

[0114] However, in the miniaturized MEMS microphone structure, the space is limited by the components mounted on the second substrate (200) and the internal volume must be secured, so the third edge portion (813, 814) may include only the fifth corner portion (813) or only the fifth corner portion (813) and the sixth corner portion (814).

[0115]

[0116] Those skilled in the art related to the embodiments described above will understand that they may be implemented in modified forms without departing from the essential characteristics of the description. Therefore, the disclosed methods should be considered in an illustrative rather than a restrictive sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalence should be interpreted as being included in the invention.

Claims

1. First substrate; A second substrate disposed on the first substrate; An adhesive layer disposed between the first substrate and the second substrate; A PSR (Photo Solder Resist) layer disposed on the second substrate; and It includes a MEMS structure disposed on the second substrate, and The above PSR layer includes an open region where the second substrate is exposed, and The above open region is a MEMS microphone comprising a first edge portion formed on the outer edge of the MEMS structure.

2. In Paragraph 1, The first edge portion includes a first corner portion and a second corner portion opposite each other, and a third corner portion and a fourth corner portion connected to the first and second corner portions and opposite each other. The above first to fourth corner portions are MEMS microphones spaced apart from each other.

3. In Paragraph 2, The above open region is a MEMS microphone including a second edge portion formed on the inner edge of the MEMS structure.

4. In Paragraph 3, The second edge portion comprises a first corner portion facing the first corner portion and the third corner portion of the first edge portion, a second corner portion facing the first corner portion and the fourth corner portion of the first edge portion, a third corner portion facing the second corner portion and the fourth corner portion of the first edge portion, and a fourth corner portion facing the second corner portion and the third corner portion of the first edge portion. The above first to fourth corner sections are MEMS microphones spaced apart from each other.

5. In Paragraph 3, It includes a hole penetrating the first substrate and the second substrate, The above MEMS structure is positioned to surround the hole, and The second edge portion of the above open area includes two corner portions opposite each other, and The above open area is a MEMS microphone comprising a first area connecting the two corner portions and the hole.

6. In Paragraph 1, It includes a signal processing element spaced apart from the MEMS structure and disposed on the second substrate, and The open region of the above PSR layer is a MEMS microphone including a third edge portion formed at the edge of the signal processing element.

7. In Paragraph 6, It includes a housing disposed on the second substrate, and The above housing includes a first side plate and a second side plate forming a corner portion, and The third edge portion includes a fifth corner portion formed between the first side plate of the housing and the signal processing element and a sixth corner portion formed between the second side plate of the housing and the signal processing element. The above-mentioned fifth corner and the above-mentioned sixth corner are spaced apart from each other.

8. In Paragraph 7, The above-mentioned fifth corner portion is formed in a line shape extending along the first direction, and A MEMS microphone in which the distance between the fifth corner portion and the second side plate in the first direction is 5% or more and 15% or less relative to the length of the second substrate in the first direction.

9. In Paragraph 8, The above-mentioned sixth corner portion is formed in a line shape extending along a second direction perpendicular to the first direction, and A MEMS microphone in which the distance between the sixth corner portion and the first side plate in the second direction is 0.2 mm or more and 0.5 mm or less.

10. In Paragraph 3, A MEMS microphone having an adhesive member disposed between the first edge portion and the second edge portion of the PSR layer on the second substrate.

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