MEMS microphone module including dual case

Abstract

The present invention relates to a MEMS microphone module including a dual case and, more specifically, to a MEMS microphone module having a dual protection structure by incorporating a second case for protecting a first case which forms an inner space including a transducer and a semiconductor unit disposed on a base substrate, the module thus being capable of preventing noise from entering the inside of a set and external pressure from causing deformation.

Description

MEMS microphone module including a double case

[0001] The present invention relates to a MEMS microphone module including a double case.

[0002] A microphone is a device that converts voice into electrical signals. Microphones can be applied to various devices, such as mobile communication devices, earphones, or hearing aids. Such microphones must possess good electronic and acoustic performance, reliability, and operability.

[0003] Capacitive microphones based on MEMS (MicroElectroMechanicalSystems, hereinafter simply referred to as 'MEMS microphones') offer superior electronic / acoustic performance, reliability, and operability compared to conventional condenser microphones (ECM microphones).

[0004] Since MEMS microphones are manufactured using MEMS-based semiconductor processes, they can be implemented in a size several to tens of times smaller than conventional ECM microphones. As such, MEMS microphones are capable of miniaturization and are widely installed in small portable devices such as mobile phones.

[0005] Figure 1 illustrates a conventional MEMS microphone module.

[0006] Referring to FIG. 1, a first case (150) is configured to protect a transducer (120) and a semiconductor part (130) placed on a base substrate (100), thereby protecting the elements within the MEMS microphone from the intrusion of foreign substances and impact.

[0007] Although sound should only be introduced through the acoustic port (112) of the MEMS microphone, in devices with various sensors, such as mobile phones, the sound of a camera driving or vibration noise of a motor may be introduced through the acoustic port (112) or the first case (150).

[0008] In order to reduce external noise, the area around the acoustic inlet (112) must be compressed with a structure such as a gasket to separate the acoustic inlet (112) from the space inside the set, and in this process, the microphone may be deformed.

[0009] To address these issues, it is necessary to develop technology that protects the microphone from deformation while simultaneously reducing the ingress of external noise.

[0010] The technical problem that the present invention aims to solve is to provide a MEMS microphone module having a double protection structure that can block noise inside the set and external pressure.

[0011] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0012] A MEMS microphone module including a double case according to the present invention for solving the above technical problem may include a base substrate having an acoustic inlet, a transducer disposed on one side of the base substrate and formed on the output side of the acoustic inlet, a semiconductor part disposed on the other side of the base substrate and electrically connected to the transducer, a first case disposed on the base substrate and forming an internal space that surrounds the transducer and the semiconductor part, and a second case formed on the outside of the first case to protect the first case.

[0013] In some embodiments of the present invention, a hole penetrating a first upper surface may be formed in the first case.

[0014] In some embodiments of the present invention, the second case may be connected to the first case through a plurality of connection structures.

[0015] In some embodiments of the present invention, the inner end of the connecting structure may be connected to an inner corner where the upper surface and the side surface of the first case meet, and the outer end of the connecting structure may be connected to an outer corner where the upper surface and the side surface of the second case meet.

[0016] In some embodiments of the present invention, a sound-absorbing material may be included between the second case and the first case.

[0017] In some embodiments of the present invention, the sound-absorbing material, the second case, and the first case may each be bonded with double-sided tape.

[0018] In some embodiments of the present invention, the base substrate comprises a first substrate and a second substrate disposed on the first substrate, and the second substrate may have one or more mounting portions formed thereon in which at least one of the first case and the second case is disposed in an area where the second substrate is bonded to the first case and the second case.

[0019] The MEMS microphone module having a double case according to the present invention can effectively block the inflow of noise generated inside the set and reduce the possibility of physical damage caused by external pressure by forming a second case to have a double protection structure. In addition, electromagnetic noise radiated by the double shielding structure can be further reduced.

[0020] Figure 1 illustrates a conventional MEMS microphone module.

[0021] FIG. 2 is a perspective view of a MEMS microphone module according to one embodiment of the present invention.

[0022] FIG. 3 is a cross-sectional view of a MEMS microphone module according to one embodiment of the present invention.

[0023] FIG. 4 is a cross-sectional view of a MEMS microphone module according to another embodiment of the present invention.

[0024] FIG. 5 is a cross-sectional view illustrating a case of a MEMS microphone module according to another embodiment of the present invention.

[0025] FIG. 6 is a cross-sectional view of a MEMS microphone module according to another embodiment of the present invention.

[0026] FIG. 7 illustrates a case arrangement structure according to one embodiment of the present invention.

[0027] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0028] "And / or" includes each of the mentioned items and all combinations of one or more.

[0029] The terms used herein are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprising" and / or "comprising" does not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0030] Furthermore, throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly" or "electrically connected" with other members or elements interposed between them.

[0031] Additionally, throughout the specification, the description that each layer (film), region, pattern, or structure is formed "on" or "under" the substrate, each layer (film), region, pad, or pattern includes both direct formation and formation through another layer. The criteria for "on" or "under" each layer are described based on the drawings.

[0032] Furthermore, expressions such as 'first, second,' etc., are used solely to distinguish multiple compositions and do not limit the order or other characteristics between the compositions.

[0033] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0034] Hereinafter, a MEMS microphone module having a double case according to the present invention will be described with reference to the drawings.

[0035] FIG. 2 is a perspective view of a MEMS microphone module according to one embodiment of the present invention, and FIG. 3 is a cross-sectional view of a MEMS microphone module according to one embodiment of the present invention.

[0036] Referring to FIGS. 2 and FIG. 3, a MEMS microphone module according to the present invention may include a base substrate (100) having an acoustic inlet (112), a transducer (120) disposed on one side of the base substrate (100) and formed on the output side of the acoustic inlet (112), a semiconductor part (130) disposed on the other side of the base substrate (100) and electrically connected to the transducer (120), a first case (150) disposed on the base substrate (100) and forming an internal space that surrounds the transducer (120) and the semiconductor part (130), and a second case (160) formed on the outside of the first case (150) to protect the first case (150).

[0037] The base substrate (100) can be implemented in various materials, and the shape and size of the base substrate (100) are not limited. A circuit pattern may be formed on the upper surface or inside of the base substrate (100) and may be electrically connected to the semiconductor part (130). The base substrate (100) is provided with an acoustic inlet (112), and the acoustic inlet (112) may penetrate from the lower surface to the upper surface of the base substrate (100).

[0038] In one embodiment, the base substrate (100) may include a rigid substrate, for example, a printed circuit board (PCB), a semiconductor substrate, or a ceramic substrate.

[0039] In another embodiment, the base substrate (100) may include a first substrate (101) and a second substrate (102). For example, the second substrate (102) may be placed on the first substrate (101) to form a single base substrate (100).

[0040] The first substrate (101) may include a rigid substrate, for example, a printed circuit board (PCB), a semiconductor substrate, or a ceramic substrate. The first substrate (101) may be composed of a single layer or may be formed by stacking multiple substrates. The second substrate (102) is placed on top of the first substrate (101) and has a plate shape. The second substrate (102) is a flexible substrate and may be, for example, a Chip on Film (COF) substrate or a Flexible Printed Circuit Board (FPCB).

[0041] A COF (Chip on Film) substrate is a substrate formed by forming a circuit or mounting components such as chips on a base film. Because it has a film shape, it is a substrate that is significantly thinner than other substrates. Using a COF substrate as a substrate for a MEMS microphone can reduce the thickness compared to using a conventional rigid substrate.

[0042] The second substrate (102) may include a 2Metal COF substrate. The 2Metal 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 or devices can be mounted on both sides of the base film.

[0043] Since flexible printed circuit boards (FPCBs) are thinner and more flexible than standard PCB boards, using a flexible printed circuit board as a substrate for a MEMS microphone can reduce the thickness.

[0044] In addition, other types of flexible substrates may be included. For example, the second substrate (102) may be an LCP (Liquid Crystal Polymer) based FPCB, a PI (polyimide) based FPCB, or a PI based COF.

[0045] The first substrate (101) and the second substrate (102) may be bonded by an adhesive layer (not shown). As a means of bonding the first substrate (101) and the second substrate (102), the adhesive layer may have a shape and size corresponding to the shape and size of the upper surface of the first substrate (101) or the lower surface of the second substrate (102). The adhesive layer may be selected as a conductive material or a non-conductive material as needed.

[0046] The above transducer (120) detects vibrations caused by sound and converts them into electrical signals. The transducer (120) is equipped with a diaphragm (121) and a back plate (122) inside, and detects the vibration when the diaphragm (121) vibrates due to external sound. The diaphragm (121) and the back plate (122) can be mounted on the surface of a MEMS substrate. The above transducer (120) is electrically connected to a semiconductor part (130) by a first connecting line (141) and transmits an electrical signal corresponding to the vibration to the semiconductor part (130). The semiconductor part (130) can be connected to a base substrate (100) by a second connecting line (143).

[0047] The semiconductor part (130) is an integrated circuit (IC) that receives an electrical signal generated by a transducer (120), amplifies and filters the electrical signal, and converts it into a usable electrical signal. The semiconductor part (130) may be, for example, an application-specific integrated circuit (ASIC) manufactured to order for a specific purpose.

[0048] When external sound is introduced through the sound inlet (112), the diaphragm (121) of the transducer (120) vibrates, and the capacitance changes according to the vibration. The semiconductor part (130) amplifies this small change in capacitance and converts it into a usable electrical signal.

[0049] The first case (150) comprises a first upper surface portion (151) and a first side portion (152). The first upper surface portion (151) covers an upper region spaced apart from the transducer (120) and the semiconductor portion (130), and the first side portion (152) is folded from the first upper surface portion (151) toward the upper surface of the base substrate (100) to cover a side region spaced apart from the outside of the transducer (120) and the semiconductor portion (130). The first case (150) has an internal space that is a resonance space. The first case (150) may be formed of a metal material and may have an internal space in the shape of a cuboid.

[0050] The outer lower portion of the first case (150) may be folded outward from the upper surface of the base substrate (100). The upper surface of the base substrate (100) may be provided with an area larger than the area of ​​the lower surface of the first case (150).

[0051] The second case (160) may be installed to cover the outer side of the first case (150). The second case (160) includes a second upper surface (161) and a second side surface (162). The second upper surface (161) covers an upper area spaced apart from the first upper surface (151), and the second side surface (162) is folded from the first upper surface (161) toward the upper surface of the base substrate (100) to cover a side area spaced apart from the first side surface (152). In this way, the second case (160) may have a space containing the first case (150) inside. The internal space of the second case (160) may have a cuboid shape.

[0052] The outer lower portion of the second case (160) may be folded outward from the upper surface of the base substrate (100). The upper surface of the base substrate (100) may be provided with an area larger than the area of ​​the lower surface of the second case (160).

[0053] Each of the first case (150) and the second case (160) may be formed from a metal material, such as stainless steel, copper-zinc alloy, or copper-nickel-zinc alloy. Additionally, each of the first case (150) and the second case (160) may be formed from an injection molded material such as polycarbonate or ABS (Acrylonitrile Butadiene Styrene). Furthermore, either the first case (150) or the second case (160) may be composed of a metal material. For example, if the first case (150) is formed from an injection molded material, the second case (160) may be formed from a metal material. Alternatively, if the first case (150) is formed from a metal material, the second case (160) may be formed from an injection molded material. Alternatively, both the first case (150) and the second case (160) may be formed of metal material.

[0054] When the first case (150) and the second case (160) are formed of a metal material, they can shield radiation from electronic circuits such as the semiconductor part (130) and prevent interference from other components, reduce ESD damage entering from the outside to minimize damage to the transducer (120), and shield RF noise. In this way, electromagnetic noise can be reduced more significantly compared to a conventional single shielding structure through a double shielding structure.

[0055] Two cases (150, 160) are connected to a base substrate (100), for example, and can be fixed by bonding them to the base substrate (100) with molten solder. And there may be a gap of at least 50 μm between the first case (150) and the second case (160).

[0056] FIG. 4 illustrates a MEMS microphone module according to another embodiment of the present invention.

[0057] Referring to FIG. 4, a second case (160) of a MEMS microphone module according to another embodiment of the present invention may be connected to the first case (150) by a plurality of connection structures (163).

[0058] The inner end of the above-described connecting structure (163) is connected to an inner corner where the first upper surface (151) and the first side surface (152) of the first case (150) meet, and the outer end is connected to an outer corner where the second upper surface (161) and the second side surface (162) of the second case (160) meet.

[0059] To explain further, the two cases (150, 160) are interconnected by a connecting structure (163), and the inner end of the connecting structure (163) is connected to the corner formed where the outer surface of the first upper surface (151) and the outer surface of the first side part (152) meet, and the outer end can be connected to the corner formed where the inner surface of the second upper surface (161) and the inner surface of the second side part (162) meet.

[0060] The connecting structure (163) formed in this way acts as a reinforcing structure, such as a bridge, when external mechanical pressure is applied to the second case (160), thereby further enhancing resistance to external pressure.

[0061] FIG. 5 is a cross-sectional view of a MEMS microphone module according to another embodiment of the present invention.

[0062] Referring to FIG. 5, a MEMS microphone module according to another embodiment of the present invention may include a sound-absorbing material (165, 167) between the second case (160) and the first case (150).

[0063] The sound-absorbing material (165, 167) may include a first sound-absorbing material (165) which is a sound-absorbing material with a plate-like structure located between the first upper surface (151) and the second upper surface (161), and a second sound-absorbing material (167) which is a sound-absorbing material with an annular structure located between the first side surface (152) and the second side surface (162).

[0064] Since the space between the two cases (150, 160) is filled with sound-absorbing material, the transmission of sound to the transducer (120) inside the first case (150) can be blocked more effectively.

[0065] The material of the above sound-absorbing material (165, 167) is not particularly limited as long as it is a material capable of absorbing acoustic vibrations. For example, mineral wool, polyester, polyurethane, etc. may be used.

[0066] At this time, the sound-absorbing material (165, 167), the second case (160), and the first case (150) can each be bonded with double-sided tape.

[0067] Meanwhile, although FIG. 5 illustrates and describes the inclusion of a first sound-absorbing material (165) and a second sound-absorbing material (167) between the first case (150) and the second case (160), the present disclosure is not limited thereto. For example, a single sound-absorbing material may be implemented to fill the entire space between the first case (150) and the second case (160), or to fill at least 90% of the space.

[0068] As such, the MEMS microphone module according to the present invention can effectively block the inflow of noise generated inside the set by forming a case with a double protection structure, and can also reduce the risk of physical damage caused by external pressure. In addition, electromagnetic noise radiated by double shielding can also be reduced.

[0069] FIG. 6 is a cross-sectional view of a MEMS microphone module according to another embodiment of the present invention.

[0070] Referring to FIG. 6, in another embodiment of the present invention, another MEMS microphone module may include a case having a hole. Specifically, the first case (150) may include a hole (170) penetrating a portion of the upper surface. By the hole (170) formed in the first case (150), the back volume inside the MEMS microphone module is increased, thereby improving the signal-to-noise ratio (hereinafter SNR) and expanding the low frequency band.

[0071] In one embodiment, the hole (170) may be positioned to overlap vertically with the transducer (120). In another embodiment, the hole (170) may be positioned not to overlap vertically with the transducer (120).

[0072] In one embodiment, the MEMS microphone module may additionally include a connection structure (163) as shown in FIG. 4. In one embodiment, the MEMS microphone module may additionally include sound-absorbing materials (165, 167) as shown in FIG. 5. In this case, the hole (170) may not overlap with the sound-absorbing materials (165, 167) in the vertical direction.

[0073] FIG. 7 illustrates a case arrangement structure according to one embodiment of the present invention.

[0074] Referring to FIG. 7, the second substrate (102) may include a seating portion (128) in which the first case (150) or the second case (160) is placed in an area joined to the first case (150) or the second case (160).

[0075] In one embodiment, the mounting portion (128) may include a first mounting portion where the first case (150) is placed and a second mounting portion where the second case (160) is placed. In another embodiment, the mounting portion (128) may be formed as a single mounting portion that is wide enough to mount the first case (150) and the second case (160) together.

[0076] The mounting portion (128) can be formed by etching the second substrate (102). At this time, metal plate half-etching can be performed on the second substrate (102). After positioning the first case (150) or the second case (160) on the mounting portion (128) and performing soldering (187), the bonding area with the second substrate (102) is widened, thereby improving bonding strength and enabling hermetic shielding. Through this, bonding reliability is improved, and SNR performance and tolerance can be improved.

[0077] In one embodiment, the mounting portion (128) may be formed as a single configuration corresponding to only one case. For example, the mounting portion (128) may be formed to mount only the first case (150) or to mount only the second case (160). A case in which the corresponding mounting portion (128) is not formed may be placed in an area of ​​the upper surface of the second substrate (102) that is not etched and may be mounted through an adhesive material other than solder.

[0078] Meanwhile, although the second substrate (102) is etched to form a mounting portion (128) in relation to FIG. 7, the present disclosure is not limited thereto. For example, it may be implemented by scratching or other surface treatment methods on the surface of the second substrate.

[0079] Although the present invention has been described above, those skilled in the art will recognize that the invention may be implemented in other forms while maintaining the technical concept and essential features of the invention.

[0080] The scope of the present invention shall be defined by the claims, but all modifications or variations derived from configurations directly derived from the descriptions in the claims, as well as configurations equivalent thereto, shall be interpreted as being included within the scope of the present invention.

Claims

1. A base substrate having an acoustic inlet; A transducer disposed on one side of the base substrate and formed on the output side of the acoustic inlet; A semiconductor part disposed on the other side of the base substrate and electrically connected to the transducer; A case disposed on the base substrate and forming an internal space that encloses the transducer and the semiconductor part; and A MEMS microphone module comprising a second case formed on the outside of the first case to protect the first case.

2. In Paragraph 1, A MEMS microphone module having a hole formed in the first case penetrating the first upper surface.

3. In Paragraph 1 or 2, The above-mentioned second case is a MEMS microphone module connected to the above-mentioned first case through a plurality of connection structures.

4. In Paragraph 3, A MEMS microphone module characterized in that the inner end of the above-described connection structure is connected to an outer corner formed by the meeting of the upper surface and the side surface of the first case, and the outer end is connected to an inner corner formed by the meeting of the upper surface and the side surface of the second case.

5. In Paragraph 1 or 2, A MEMS microphone module comprising a sound-absorbing material between the second case and the first case.

6. In Paragraph 5, A MEMS microphone module in which the sound-absorbing material, the second case, and the first case are each bonded with double-sided tape.

7. In Paragraph 1, The above base substrate includes a first substrate and a second substrate disposed on the first substrate, and A MEMS microphone module having one or more mounting portions formed on the second substrate, wherein at least one of the first case and the second case is disposed in an area where the second substrate is bonded to the first case and the second case.

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