MEMS microphone

Abstract

A MEMS microphone according to one embodiment of the present invention comprises: a first substrate; a second substrate stacked on the first substrate; a housing coupled to the first substrate and having an accommodation space formed therein; a MEMS structure disposed on the second substrate in the accommodation space; and a signal processing element spaced apart from the MEMS structure and disposed on the second substrate in the accommodation space.

Description

MEMS Microphone

[0001] The present invention relates to a MEMS microphone, and more specifically, to a MEMS microphone in which a substrate is formed using a wafer process.

[0002] Typically, audio devices use electrodes to vibrate a diaphragm to generate sound. Recent technological advancements have led to significant advancements in the audio device field. These devices are increasingly used in diverse applications, including portable terminals and hearing aids. As the devices they are used in become slimmer, the devices themselves are also becoming smaller.

[0003] Additionally, microphones utilizing MEMS (Micro Electro Mechanical Systems), a semiconductor technology, have recently been developed and used. MEMS is a technology that enables the manufacturing of tiny mechanical components. These MEMS microphones can be categorized into electrostatic and piezoelectric types, including the common condenser type.

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

[0005] The technical problem to be solved by the present invention is to provide a MEMS microphone with simplified process and improved reliability by utilizing a wafer process, which is one of the semiconductor processes.

[0006] In order to solve the above technical problem, a MEMS microphone according to one embodiment of the present invention may include: a first substrate; a second substrate laminated on the first substrate; a housing coupled to the first substrate to form an accommodation space therein; a MEMS structure disposed on the second substrate in the accommodation space; and a signal processing element disposed on the second substrate in the accommodation space, spaced apart from the MEMS structure.

[0007] Additionally, the area of ​​the first substrate may be wider than the area of ​​the second substrate.

[0008] Additionally, the first substrate may include a border, which is an area where the second substrate is not laminated.

[0009] Additionally, the housing can be coupled to the frame.

[0010] Additionally, the lower surface of the housing can be soldered to the upper surface of the first substrate.

[0011] Additionally, the first substrate may include a border, which is an area where the second substrate is not laminated, and the housing bottom surface may be soldered to the border.

[0012] Additionally, the solder may be filled in the space between the lower surface of the housing and the second substrate.

[0013] Additionally, the vertical length of the first substrate may be longer than the vertical length of the second substrate by a first set length, and the horizontal length of the first substrate may be longer than the horizontal length of the second substrate by a second set length.

[0014] Additionally, the first substrate may include one of a 2Metal COF substrate, an FPCB, and a PI-based COF substrate, and the second substrate may include a substrate made of a metal material.

[0015] First of all, since the manufacturing equipment used in conventional semiconductor processes can be used to manufacture MEMS microphone substrates, not only is there no need for time or cost for manufacturing or ordering separate manufacturing equipment, but it also has the effect of being more efficient in terms of productivity than conventional substrate manufacturing methods.

[0016] In particular, a process of bonding a first substrate and a second substrate is required to manufacture a substrate used in a MEMS microphone. Conventional bonding processes mainly utilize a thermocompression bonding process or a mounting process utilizing surface mount technology (SMT), and this has the effect of solving problems occurring in both processes.

[0017] First, when manufacturing a substrate through a thermocompression bonding process, since the process is performed manually, not only is the tolerance precision low, but there is also a problem that a short circuit occurs in the pad of the first substrate due to the flow phenomenon of the bonding sheet during the process of bonding using a conductive bonding sheet. However, according to an embodiment of the present invention, this problem is effectively solved.

[0018] In addition, when utilizing the SMT mounting process, solder is mostly utilized, but in the reflow process of applying and joining the solder, the first and second substrates are not properly aligned and are joined misaligned due to rotational joining, or the flatness of the substrates is not guaranteed due to the height deviation of the applied solder, which causes problems such as lowered reliability of the product in the packaging process. This has the effect of solving these problems.

[0019] In addition, the process according to the embodiment of the present invention has the advantage of simplifying the process by eliminating a separate manual process or solder application process.

[0020] In addition, since the housing is directly contacted and bonded to the first substrate, not only is the stability high, but the housing can be bonded to the first substrate only through a soldering process without the need for a separate patterning process or mounting process on the second substrate or bonding sheet for the housing bonding, which not only simplifies the process but also has the effect of increasing the reliability of the connection between the housing and the first substrate and the reliability of the package accordingly.

[0021] FIG. 1 is a side view illustrating the structure of a MEMS microphone according to an embodiment of the present invention.

[0022] FIG. 2 is a drawing showing the connection relationship between the housing and the first substrate of the MEMS microphone according to an embodiment of the present invention.

[0023] Fig. 3 is a top view showing the structure of a MEMS microphone according to an embodiment of the present invention.

[0024] FIG. 4 is a drawing for explaining a process step for manufacturing a substrate of a MEMS microphone according to an embodiment of the present invention.

[0025] FIG. 5 is a wafer drawing for manufacturing a second substrate unit of a MEMS microphone substrate according to an embodiment of the present invention.

[0026] FIG. 6 is a drawing for explaining a panel on which a first substrate unit of a MEMS microphone substrate according to an embodiment of the present invention is arranged and a lamination process of the first substrate unit and the second substrate unit.

[0027] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0028] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0029] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0030] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0031] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0032] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0033] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0034] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0035] Variations according to the present embodiment may include some components of each embodiment and some components of other embodiments. That is, a variation may include one embodiment among various embodiments, but may omit some components and include some components of the corresponding other embodiment. Or, the opposite may be true. The features, structures, effects, etc. described in the embodiments are included in at least one embodiment and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified in other embodiments by a person having ordinary skill in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as being included within the scope of the embodiments.

[0036] FIG. 1 is a side view illustrating the structure of a MEMS microphone according to an embodiment of the present invention, FIG. 2 is a drawing illustrating the connection relationship between a housing and a first substrate of a MEMS microphone according to an embodiment of the present invention, and FIG. 3 is a top view illustrating the structure of a MEMS microphone according to an embodiment of the present invention.

[0037] Referring to FIGS. 1 to 3, a MEMS microphone according to one embodiment of the present invention may include a first substrate (100), a second substrate (200), a MEMS structure (300), a housing (400), a signal processing element (500), a capacitor (600), and a bonding sheet (700).

[0038] The first substrate (100) is placed at the bottom of the MEMS microphone and is a substrate on which a circuit can be formed in a plate shape. The first substrate (100) is a flexible substrate and may be a COF (Chip on Film) substrate or a flexible printed circuit board (FPCB). 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 types of the first substrate (100) are not limited to the examples described above.

[0039] A COF (Chip on Film) substrate is a substrate formed by forming circuits or mounting chips or other components on a base film. Because it has a film-like shape, it is thinner than other substrates. Using a COF substrate as the substrate for a MEMS microphone can reduce thickness compared to using a conventional rigid substrate.

[0040] 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 metal layers are laminated on the upper and lower surfaces of the base film so that circuits can be formed on both sides of the base film or devices can be mounted thereon.

[0041] The first substrate (100) may include a via hole. In this case, the first substrate (100) may connect circuits or elements formed on both sides through a metal layer (e.g., a via) formed in the via hole. Here, the via hole may be a micro via hole and may be configured with a size of 25 um or less. Compared to a single-sided COF, the degree of integration can be increased, the degree of freedom during packaging is improved, and a fine pitch is possible by arranging circuits or elements on both sides. When only a rigid substrate is used, the basic thickness is thick during design, making it difficult to apply a fine pitch, but when a COF substrate is used, it is significantly thinner than the substrate, making it possible to apply a fine pitch, so the size of the MEMS microphone package can be reduced by more than 50%.

[0042] A flexible printed circuit board (FPCB) is a flexible circuit board. It is also flexible and thinner than standard PCBs, allowing for a reduction in the thickness of the MEMS microphone substrate. Other types of flexible substrates may also be included.

[0043] The area of ​​the first substrate (100) may be larger than the area of ​​the second substrate (200). The cross-sectional area of ​​the first substrate (100) may be formed to be larger than the cross-sectional area of ​​the second substrate (200), and the length of the first substrate (100) may also be formed to be longer than the length of the second substrate (200) by a set length. In detail, if the direction of the longer length in the first substrate (100) is defined as vertical and the direction of the shorter length is defined as horizontal, the horizontal length of the first substrate (100) may be shorter than the horizontal length of the second substrate (200) by a first set length (D1), and the vertical length of the first substrate (100) may be shorter than the vertical length of the second substrate (200) by a second set length (D2). The first set length (D1) and the second set length (D2) may be the same length or different lengths.

[0044] Due to the difference in size between the areas of the first substrate (100) and the second substrate (200), when the first substrate (100) and the second substrate (200) are laminated by the bonding sheet (700), the border (or edge) of the first substrate (100) may be exposed to the outside by an area corresponding to the set length. Specifically, the second substrate (200) may be laminated so as to vertically overlap the inner side of the first substrate (100). Accordingly, each of the borders arranged vertically on both sides of the first substrate (100) may not vertically overlap with the second substrate (200) by half the length (D1 / 2) of the first set length, and each of the borders arranged horizontally on both sides of the first substrate (100) may not vertically overlap with the second substrate (200) by half the length (D2 / 2) of the second set length. A housing (400) can be directly coupled to a border of the first substrate (100) that does not vertically overlap the second substrate (200).

[0045] The first substrate (100) may include an acoustic hole (10). The cross-sectional area of ​​the acoustic hole (10) may be circular, but is not limited thereto. A MEMS structure (300) may be arranged on the upper portion of the acoustic hole (10) formed in the first substrate (100).

[0046] A first substrate (100) may be electrically connected to a signal processing element (500) and a capacitor (600). A metal layer may be formed on the first substrate (100) to be electrically connected to the signal processing element (500) and the capacitor (600). Here, the metal layer may include a plurality of pads, a plurality of connection circuits, and a plurality of vias. The pads may vertically overlap with the vias and contact them, or may contact an external substrate or element. The connection circuits may connect between pads arranged on the same layer. The vias may be formed in via holes penetrating a base film or an insulating layer. Hereinafter, to help understanding the description, the pads formed on the first substrate (100) are referred to as pads (110).

[0047] Pads (110) and connection circuits (120) of the same or different shapes may be formed on the upper and lower surfaces of the first substrate (100). A plurality of first pads (110) and first connection circuits (120) may be formed on the upper surface of the first substrate (100), and a plurality of second pads (not shown) and second connection circuits (not shown) may be formed on the lower surface of the first substrate (100). A signal processing element and a capacitor may be electrically connected to the plurality of first pads (110) and first connection circuits (120).

[0048] In this case, a plurality of first pads (110) formed on the upper surface of the first substrate (100) can be electrically connected to a plurality of second pads (not shown) formed on the lower surface of the first substrate (100). The first pads (110) and the second pads (not shown) of the first substrate (100) can be electrically connected through a connection circuit or via, and can be arranged at positions where they overlap each other in the vertical direction or can be arranged at different positions. That is, there is no limitation on the arrangement of the first pads (110) and the second pads (not shown) of the first substrate (100) as long as they are electrically connected to each other.

[0049] A connection circuit may be arranged on the first substrate (100). The connection circuit may be a pattern circuit for electrically connecting pads formed on the upper and lower surfaces of the first substrate (100). The connection circuit may include a first connection circuit (120) arranged on the upper surface of the first substrate (100) and a second connection circuit (not shown) arranged on the lower surface of the first substrate (100). The first connection circuit (120) may extend from the first pad (110) to an arbitrary position and may be electrically connected to the second pad (not shown) through a via. In addition, the second connection circuit (not shown) may extend from the second pad (not shown) to an arbitrary position. The connection circuit (120) may have a pattern shape designed to allow the first pad (110) and the second pad (not shown) to be arranged at different positions. In this case, the signal processing element (500) and the capacitor (600) can be electrically connected to the first substrate (100) via the first pad (110). In addition, the first pad (110) to which the first connection circuit (120) is connected may not be connected to a via as needed. In this case, a via may be connected to the first connection circuit (120), or the first connection circuit (120) may be connected to another first pad (110) to which a via is connected.

[0050] A base film (130) may be disposed on an area excluding the pads and connection circuits formed on the upper and lower surfaces of the first substrate (100). In one embodiment, the base film (130) may include polyimide. For example, a portion of the base film (130) may be exposed together with the first pad (110) and the first connection circuit (120) through the cavity (210) of the second substrate (200).

[0051] The second substrate (200) is laminated to be placed on top of the first substrate (100) and has a plate shape. The second substrate (200) may be a rigid substrate to supplement the rigidity of the first substrate (100), and may include, for example, one or more of a metal plate, a SUS, and a reinforcing plate. SUS is a type of steel in which chromium is mixed with iron to enhance corrosion resistance, and refers to a high-strength substrate. In addition to the above-described configuration, various reinforcing plates made of metal materials may be used for the second substrate (200). Since the second substrate (200) supplements the rigidity of the first substrate (100), the flexible first substrate (100) can maintain its shape.

[0052] The area of ​​the second substrate (200) may be smaller than the area of ​​the first substrate (100). The second substrate (200) may be formed so that its cross-sectional area is smaller by a set length than the cross-sectional area of ​​the first substrate (100). The vertical length of the second substrate (200) may be smaller by the second set length than the vertical length of the first substrate (100), and the horizontal length of the second substrate (200) may be smaller by the first set length than the horizontal length of the first substrate (100). Accordingly, when the housing (400) is coupled to the edge of the first substrate (100), the second substrate (200) may be accommodated in the accommodation space within the housing (400).

[0053] The second substrate (200) may include one or more cavities (210). The second substrate (200) is disposed on top of the first substrate (100), and the first substrate (100) may be exposed to the upper portion of the second substrate (200) through the cavities (210) of the second substrate (200). The first substrate (100) may be exposed to the upper portion of the second substrate (200) by having a first pad (110) and a first connection circuit (120) disposed in the space where the cavities (210) of the second substrate (200) are 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 pad (110) and the first connection circuit (120) formed on the upper surface of the first substrate (100) can be exposed to the upper portion 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 the signal processing element (500) and the capacitor (600) through the cavity (210) formed in the second substrate (200).

[0054] 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, and may have a size corresponding to the acoustic hole formed in the first substrate (100). The acoustic hole formed in the second substrate (200) may be in communication with the acoustic hole formed in the first substrate (100) to form one acoustic hole (10), and a MEMS structure (300) may be arranged on the acoustic hole (10).

[0055] The bonding sheet (700) is a means for bonding the first substrate (100) and the second substrate (200). The bonding sheet (700) is arranged between the upper surface of the first substrate (100) and the lower surface of the second substrate (200) to bond the first substrate (100) and the second substrate (200). The bonding sheet (700) may have a shape and size corresponding to the shape and size of the second substrate (200). Accordingly, the bonding sheet (700) may be arranged within the receiving space formed by the housing (400), and the edge of the first substrate (100) is not provided with the bonding sheet (700).

[0056] A housing (400) may be placed on a first substrate (100). A MEMS structure (300), a signal processing element (500), and a capacitor (600) may be placed on a second substrate (200). The capacitor (600) may be selectively placed on the second substrate (200) as needed.

[0057] The housing (400) is a means that is placed on the upper portion of the first substrate (100) and forms an accommodation space therein. The housing (400) may be formed in a cover shape with an open lower surface, and the lower surface of the housing (400) may be bonded to the upper surface of the first substrate (100) to form the accommodation space. In detail, the housing (400) may be bonded to the lower surface of the housing (400) on the upper portion of the first substrate (100), thereby bonding the housing (400) and the first substrate (100).

[0058] The lower surface of the housing (400) and the first substrate (100) may be joined by soldering. The solder (410) may be arranged in a manner that fills the space between a portion of the side surface connected to the lower surface of the housing (400) and the side surface of the second substrate (200) while bonding the lower surface of the housing (400) and the edge of the first substrate (100), thereby closing the space between a portion of the side surface connected to the lower surface of the housing (400) and the side surface of the second substrate (200). Meanwhile, the present disclosure is not limited thereto, and the housing (400) may be implemented so as to be in close contact with the side surface of the second substrate (200), and the solder (410) may bond the lower surface of the housing (400) and the edge of the first substrate (100). As a result, the side surface of the second substrate (200) may not be exposed to the receiving space by the solder (410). The solder (410) is arranged to surround the lower surface of the housing (400) to prevent short circuits or defects resulting from contact between the housing (400) and the second substrate (200). Due to this structure, the second substrate (200) can be arranged within the receiving space formed by the housing (400).

[0059] The housing (400) may be composed of nickel silver or SUS. Nickel silver is a material containing 15-30% zinc and 10-20% nickel in copper, and solder joints can be made without plating in the raw material state. When plating is applied to the seating area of ​​the housing (400), solder joint adhesion can be improved. Ni+Au plating can be applied. Both electroless and electrolytic plating processes can be applied. Although SUS contains nickel, solder joint adhesion may be reduced if plating is not performed. Therefore, plating can be applied. Unlike nickel silver, when electroless plating is applied, plating adhesion on the SUS surface may be reduced, so plating can be performed using an electrolytic plating process.

[0060] The MEMS structure (300) may be placed within a receiving space formed by the housing (400). The MEMS structure (300) may include a body (310), a back plate (330), and a vibration plate (320). The MEMS structure (300) may be placed on the upper portion of the second substrate (200), and the lower portion of the MEMS structure (300) may be placed at a position adjacent to the sound hole (10).

[0061] The body (310) is a means that can form a partition wall by surrounding the sound hole formed in the second substrate (200). The body (310) can be electrically connected to the first substrate (100) through a signal processing element (500). In addition, an sound hole (360) communicating with the sound hole can be formed in the body (310). The body (310) can be directly connected to the second substrate (200), but if necessary, the body (310) can be directly connected to the first substrate (100) through the cavity (210) of the second substrate (200), and there is no limitation thereto.

[0062] The body (310) may be formed with an acoustic hole (360). 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 be introduced through the acoustic hole (360).

[0063] The back plate (330) and the vibration plate (320) may be placed in the sound hole (360) formed in the body. The vibration plate (320) may vibrate due to the sound pressure when sound is introduced from the outside through the sound hole (360), and the back plate (330) may sense the sound signal by measuring the capacitance according to the vibration of the vibration plate (320). In the drawing, the back plate (330) is depicted as being positioned above the vibration plate, but the vibration plate (320) may also be positioned above the back plate (330).

[0064] Although not shown, 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 back plate (330) and the vibration plate (320), and may be electrically connected to a signal processing element (500) to be described later via wires or the like. The body pads serve as a means for electrical connection, and their shapes and materials are known in the art, and thus a description thereof will be omitted.

[0065] The signal processing element (500) is electrically connected to the MEMS structure (300) and can process an electric signal sensed by the MEMS structure (300). The MEMS structure (300) and the signal processing element (500) can be electrically connected via a body pad. For example, the MEMS structure (300) and the signal processing element (500) can be connected by wires via wire bonding. In another example, the MEMS structure (300) and the signal processing element (500) can be electrically connected while being mounted on a 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 can be arranged on the signal processing element (500) to be connected to the body pad of the MEMS structure (300) via wire bonding.

[0066] The signal processing element (500) can be electrically connected to the first substrate (100). The signal processing element (500) can be electrically connected to the first pad (110) of the first substrate (100) through the cavity (210) formed in the second substrate (200). For example, the signal processing element (500) and the first substrate (100) can be connected by wires through wire bonding. As another example, the first substrate (100) and the signal processing element (500) can be electrically connected while being mounted on the first substrate (100) in a flip-chip form. When the first substrate (100) and the signal processing element (500) are wire bonded, the first pad (110) of the first substrate (100) and the signal pad of the signal processing element (500) can be connected through wire bonding. The signal processed in the signal processing element (500) can be transmitted to the outside that requires the signal through the first pad (110) and the first connection circuit (120) of the first substrate (100).

[0067] The signal processing element (500) can amplify a signal sensed by 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 and may be formed in a chip form. The signal processing element may include an ASIC and an En-cap that coats the ASIC.

[0068] The signal processing element (500) may be placed on 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 spaced apart from the MEMS structure (300) in an accommodation space formed inside the housing (400) and may receive a signal from the MEMS structure (300). Since signal transmission between the MEMS structure (300) and the signal processing element (500) occurs in the accommodation space formed by the housing (400), external interference is reduced, thereby reducing noise.

[0069] A capacitor (600) may be selectively placed on the upper portion of the second substrate (200) as needed. When the capacitor (600) is placed, the PSRR performance, which is the RF-related noise described above, may be improved, and the PSR performance, which is the power-related noise, may be improved. That is, noise-related performances such as SNR, PSRR, and PSR may be improved through the capacitor (600). The capacitor (600) may be electrically connected to the signal processing element (500). As a result, the capacitor (600) may remove noise during the signal processing process in the signal processing element (500).

[0070] The capacitor (600) may be placed on the second substrate (200) and electrically connected to the signal processing element (500) and the first substrate (100). The capacitor (600) may be electrically connected to the signal processing element (500) and the first substrate (100) via a wire. When the capacitor (600) is connected to the first substrate (100) via a wire, it may be connected to the first pad (110) or the first connection circuit (120) formed on the first substrate (100) exposed through the cavity of the second substrate (200) via the wire.

[0071] However, the capacitor (600) may be electrically connected to the first substrate (100) by being mounted on the second substrate (200) or the signal processing element (500) in a flip-chip form as well as by bonding through wires. In the case of a MEMS microphone, since miniaturization is essential, there are many cases where the capacitor (600) is not placed in the circuit design due to insufficient space for placement. In this case, a problem occurs in which the performance of SNR, PSR, and PSRR is degraded due to power noise or RF noise. In the case of power noise filtering for improving SNR and PSR performance, the frequency of the noise is at the level of 0.1uF to 10uF, whereas in the case of RF noise filtering for improving SNR and PSRR performance, the frequency of the noise is at the level of 10pF to 500pF, so they have different frequency bands. When multiple capacitors (600) are arranged, the filtering noise frequency of each capacitor (600) can be determined differently, and thus, there is an effect of improving all performances of SNR, PSR, and PSRR.

[0072] Below, a process for manufacturing a substrate of a MEMS microphone according to an embodiment of the present invention is described. FIG. 4 is a drawing for explaining a process step for manufacturing a substrate of a MEMS microphone according to an embodiment of the present invention, FIG. 5 is a wafer drawing for manufacturing a second substrate unit of a substrate of a MEMS microphone according to an embodiment of the present invention, and FIG. 6 is a drawing for explaining a process for laminating a panel on which a first substrate unit of a substrate of a MEMS microphone according to an embodiment of the present invention is arranged and a first substrate unit and a second substrate unit.

[0073] Referring to FIGS. 4 to 6, the method for manufacturing a substrate of a MEMS microphone according to an embodiment of the present invention may include a wafer preparation step (A), a bonding sheet lamination step (B), a mounting step (C), a dicing step (D), a panel preparation step (E), and a bonding step (F).

[0074] Referring to Fig. 5, the wafer preparation step (A) is a step of preparing a second substrate unit in the form of a wafer (W). The wafer (W) may have a circular shape and a size of one or more of 6, 8, and 12 inches, but is not limited thereto. The wafer (W) may be prepared by sequentially arranging a set number of second substrate units (200) in the up, down, left, and right directions through an etching process, in which cavities (210) and patterns are formed.

[0075] In one embodiment, the second substrate unit (200) may include a bridge (BR) structure connecting adjacent edges. The bridge structure may increase the efficiency of the dicing process described below. For example, a specific second substrate unit (200) (hereinafter referred to as a target second substrate unit (200)) may have a bridge structure connecting a lower edge of a second substrate unit (200) positioned immediately above and an upper edge of the target second substrate unit (200). In addition, the target second substrate unit (200) may have a bridge structure connecting an upper edge of a second substrate unit (200) positioned immediately below and a lower edge of the target second substrate unit (200). In addition, the target second substrate unit (200) may have a bridge structure connecting a right edge of a second substrate unit (200) positioned immediately to the left and a left edge of the target second substrate unit (200). Additionally, the target second substrate unit (200) may have a bridge structure connecting the left edge of the second substrate unit (200) positioned immediately to the right and the right edge of the target second substrate unit (200).

[0076] The bridge structure of the second substrate unit (200) may be removed due to the dicing process, but depending on the embodiment, the second substrate (200) may also include a protrusion at a position corresponding to the bridge structure. For example, the second substrate (200) may include a protrusion that protrudes outward at at least one of the edges of the four sides.

[0077] The bonding sheet lamination step (B) is a step of thermally compressing a bonding sheet (700) to the lower surface of a wafer (W) through a lamination process to bond the first substrate unit (100) and the second substrate unit (200), which will be described later. In this case, the bonding sheet (700) may have a cross-section corresponding to the cross-section of the wafer (W). As the wafer (W) and the bonding sheet (700) are thermally compressively bonded to each other through the lamination process, the upper surface of the bonding sheet (700) may be bonded to the lower surface of the second substrate unit (200), and the area of ​​the bonding sheet (700) may be prepared to have the same area as the area of ​​the second substrate unit (200).

[0078] The mounting step (C) is a preparatory step for dicing a wafer (W) having a bonding sheet (700) adhered to the lower surface. This step involves mounting and bonding the wafer to a ring frame and forming a protective film (t) on the upper surface. In order to fix the position of the wafer in the dicing process described later, the wafer may be bonded to the ring frame, and the protective film (t) may prevent the second substrate unit from being damaged after dicing in the dicing process. Here, the protective film (t) may include a UV tape for dicing.

[0079] The dicing step (D) is a cutting step in which a plurality of second substrate units (200) arranged on the wafer (W) are diced to separate each second substrate unit (200). In the dicing step, a plurality of second substrate units (200) can be generated. Since a protective film (t) is formed on the upper surface of the wafer (W), the second substrate units (200) are prevented from being damaged or cut in the dicing step (D), thereby increasing product reliability.

[0080] The panel preparation step (E) is a step of preparing a panel (P) on which first substrate units (100) are arranged. The panel (P) may be arranged such that a plurality of first substrate units (100) are aligned in a certain direction so that second substrate units (200) can be picked up and arranged in the bonding step described later. A plurality of first substrate units (100) may be aligned at a certain interval in the x-axis and y-axis directions on the panel (P).

[0081] In the bonding step (F), the second substrate unit (200) is arranged and bonded to the panel (P) on which the first substrate unit (100) is arranged. Referring to FIG. 6, a plurality of first substrate units (100) may be arranged on the panel. In this case, the cross-sectional area of ​​the first substrate unit (100) may be larger than the cross-sectional area of ​​the second substrate unit (200). In the dicing step (D), the cut second substrate units (200) are arranged at the first substrate unit (100) arrangement positions on the panel (P) on which the first substrate units (100) are arranged, and then, by utilizing a die attach process, the first substrate unit (100) and the second substrate unit (200) in which the bonding sheet (700) is heat-cured are joined to each other, thereby manufacturing a substrate panel on which a plurality of substrate units of the MEMS microphone are arranged. After this, the microphone substrate can be manufactured by individually cutting the substrate units through a dicing process.

[0082] The MEMS microphone according to the embodiments of the present invention as described above has the following effects.

[0083] First of all, since the manufacturing equipment used in the conventional semiconductor process can be used to manufacture the MEMS microphone substrate, not only does it eliminate the time and cost of manufacturing or ordering separate manufacturing equipment, but it also has the effect of higher efficiency in terms of productivity compared to the conventional substrate manufacturing method. In particular, among the manufacturing processes described above, in the case of the wafer preparation step (A), the bonding sheet lamination step (B), the mounting step (C), and the dicing step (D), the wafer manufacturing process equipment, lamination equipment, and mounting and dicing equipment used in the semiconductor process can be utilized as is.

[0084] In addition, a process of bonding a first substrate and a second substrate is required to manufacture a substrate used in a MEMS microphone. Conventional bonding processes mainly utilize a thermocompression bonding process or a mounting process utilizing surface mount technology (SMT), which causes the aforementioned problems. However, in the case of the embodiment of the present invention, there is an effect of solving problems occurring in both processes.

[0085] First, when manufacturing a substrate through a thermocompression bonding process, since the process is performed manually, not only is the tolerance precision low, but there is also a problem that a short circuit occurs in the pad of the first substrate due to the flow phenomenon of the bonding sheet during the process of bonding using a conductive bonding sheet. However, according to an embodiment of the present invention, this problem is effectively solved.

[0086] In addition, when utilizing the SMT mounting process, solder is mostly utilized, but in the reflow process of applying and joining the solder, the first and second substrates are not properly aligned and are joined in a rotational state, resulting in misalignment, or the flatness of the substrates is not guaranteed due to the height deviation of the applied solder, resulting in a problem of lowered product reliability in the packaging process. This has the effect of solving these problems.

[0087] In addition, the process according to the embodiment of the present invention has the advantage of simplifying the process by eliminating a separate manual process or solder application process.

[0088] In addition, since the housing is directly contacted and bonded to the first substrate, not only is the stability high, but the housing can be bonded to the first substrate only through a soldering process without the need for a separate patterning process or mounting process on the second substrate or bonding sheet for the housing bonding, which not only simplifies the process but also has the effect of increasing the reliability of the connection between the housing and the first substrate and the reliability of the package accordingly.

[0089] Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from the essential characteristics of the above-described description. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. First substrate; A second substrate laminated on the first substrate; A housing coupled to the first substrate to form an accommodation space therein; A MEMS structure disposed on the second substrate in the above-mentioned receiving space; A MEMS microphone comprising a signal processing element disposed on the second substrate in the receiving space and spaced apart from the MEMS structure.

2. In paragraph 1, A MEMS microphone in which the first substrate area is larger than the second substrate area.

3. In paragraph 2, The above first substrate is a MEMS microphone including a border which is an area where the second substrate is not laminated.

4. In paragraph 3, The above housing is a MEMS microphone coupled to the above frame.

5. In paragraph 1, A MEMS microphone in which the lower surface of the housing is soldered to the upper surface of the first substrate.

6. In paragraph 5, The first substrate includes a border, which is an area where the second substrate is not laminated, The above housing bottom is a MEMS microphone that is soldered to the above frame.

7. In paragraph 5 or 6, A MEMS microphone in which the solder is filled in the space between the lower surface of the housing and the second substrate.

8. In paragraph 2, The vertical length of the first substrate is longer than the vertical length of the second substrate by the first set length, A MEMS microphone in which the horizontal length of the first substrate is longer than the horizontal length of the second substrate by a second set length.

9. In paragraph 1, The above first substrate is a MEMS microphone including one of a 2Metal COF substrate, an FPCB, and a PI-based COF substrate.

10. In paragraph 1, The above second substrate is a MEMS microphone including a substrate made of metal material.

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