KR20240008497A - Mems micorpohone package - Google Patents

Abstract

The MEMS microphone package disclosed in an embodiment of the invention includes a base substrate having an acoustic inlet; a transducer disposed on one side of the base substrate and disposed on an exit side of the sound inlet; a semiconductor portion disposed on the other side of the base substrate and electrically connected to the transducer; a case disposed on the base substrate and having an internal space to protect the transducer and the semiconductor unit; and a sound-absorbing means disposed on the inner surface of the case and blocking or absorbing external noise.

Description

MEMS Microphone Package{MEMS MICORPOHONE PACKAGE}

The invention relates to a MEMS microphone package.

It is a device that converts voice into electrical signals. Microphones can be applied to various communication devices such as mobile communication devices such as mobile terminals, earphones, or hearing aids. These microphones must have good electronic/acoustic performance, reliability and operability.

Capacitive microphone based on MEMS (MicroElectroMechanical System) (hereinafter simply referred to as 'MEMS microphone') has better electronic/acoustic performance, reliability, and operability compared to conventional electret condenser microphones (ECM microphones). This is excellent.

MEMS microphones are manufactured using a MEMS-based process, so processes up to 6 inches, 8 inches, or 12 inches are possible depending on the manufacture of the microphone in the form of an on-chip based on CMOS (Complementary Metal-Oxide Semiconductor). Therefore, MEMS microphones can be implemented in sizes that are several to tens of times smaller than ECM microphones. MEMS microphones can be miniaturized, so they can be installed in devices such as mobile phones, hearing aids, etc.

In order to remove noise, MEMS microphones actually detect external noise and transmit an opposite removal signal of the same size to the outside. However, the circuit becomes complex to implement this, and there is a problem of ineffectiveness due to differences in surrounding noise. there is. Additionally, depending on how you wear the headset or earphones, the noise removal effect may vary or howling may occur. In addition, capacitor mounting is necessary to eliminate low-frequency noise, but mounting capacitors is difficult due to space constraints in mobile devices.

Embodiments of the invention provide a new MEMS microphone package that can solve the above problems.

Embodiments of the invention provide a MEMS microphone package having a means or member for absorbing or blocking a specific frequency band or external noise.

An embodiment of the invention provides a MEMS microphone package having a sound-absorbing means or sound-absorbing member having a metamaterial or metasurface on the inner surface of a metal case or the inner or outer side of the sound inlet.

A MEMS microphone package according to an embodiment of the invention includes a base substrate having an acoustic inlet; a transducer disposed on one side of the base substrate and disposed on an exit side of the sound inlet; a semiconductor portion disposed on the other side of the base substrate and electrically connected to the transducer; a case disposed on the base substrate and having an internal space to protect the transducer and the semiconductor unit; and a sound-absorbing means disposed on the inner surface of the case and blocking or absorbing external noise.

According to an embodiment of the invention, the acoustic inlet may penetrate from the lower surface of the base substrate to the lower part of the transducer.

According to an embodiment of the invention, the acoustic inlet may be connected to the lower part of the transducer from the side of the base substrate.

According to an embodiment of the invention, the sound absorbing means may be a meta surface.

According to an embodiment of the invention, the thickness of the meta surface is λ/30 or less, and λ may be the wavelength of noise.

A MEMS microphone package according to an embodiment of the invention includes a base substrate having an acoustic inlet; a transducer disposed on one side of the base substrate and disposed on an exit side of the sound inlet; a semiconductor portion disposed on the other side of the base substrate and electrically connected to the transducer; a case disposed on the base substrate and having an internal space to protect the transducer and the semiconductor unit; And it may include a first sound absorption means disposed on the outer or inner surface of the base substrate and blocking or absorbing external noise.

According to an embodiment of the invention, the acoustic inlet is disposed on the lower surface or side of the base substrate to be connected to the internal hole of the transducer, and the first sound absorption means is disposed on the incident side of the acoustic inlet and is connected to the inner hole of the base substrate. Can be attached to the outside.

According to an embodiment of the invention, the acoustic inlet is disposed on the bottom or side of the base substrate to be connected to the internal hole of the transducer, and the first sound absorption means is disposed on the output side of the acoustic inlet and is connected to the internal hole of the transducer. Can be attached to the top.

According to an embodiment of the invention, the first sound absorption means may be a meta surface.

According to an embodiment of the invention, the thickness of the meta surface is λ/30 or less, λ is the wavelength of noise, and the sound absorption rate of the meta surface may be 70% or more.

According to an embodiment of the invention, it includes a second sound-absorbing means disposed on the inner surface of the case, and the first and second sound-absorbing means can absorb or block external noise having different center frequencies.

According to an embodiment of the invention, an encapsulant for sealing the semiconductor unit may be further included.

According to the MEMS microphone package of an embodiment of the invention, reliability of noise removal can be improved by removing external noise using a sound-absorbing means or member that absorbs only the frequencies corresponding to the noise.

According to the MEMS microphone package of an embodiment of the invention, the sound absorbing means or member can be installed on the inner surface of the metal case, or on the inside or outside of the acoustic inlet, so that components such as capacitors are not mounted on the board or do not require mounting space. There is an effect that is not needed.

The reliability of the MEMS microphone package of an embodiment of the invention and a mobile device having the same can be improved.

Figure 1 is a diagram showing the structure of a MEMS microphone package according to an embodiment of the invention.
Figure 2 is a diagram explaining external noise flowing into the MEMS microphone package.
Figure 3 is a diagram showing a first modified example of a MEMS microphone package according to an embodiment of the invention.
Figure 4 is a diagram showing a second modified example of the MEMS microphone package according to an embodiment of the invention.
Figure 5 is a diagram showing a third modified example of a MEMS microphone package according to an embodiment of the invention.
Figure 6 is a diagram showing a fourth modified example of a MEMS microphone package according to an embodiment of the invention.
Figure 7 is a diagram explaining external noise absorbed by the MEMS microphone package of the invention.
Figure 8 is a diagram for explaining the sound absorption means included in the MEMS microphone package of the invention.

Hereinafter, an antenna module according to an embodiment of the present invention will be described in detail with reference to the attached drawings. The described embodiments are provided so that those skilled in the art can easily understand the technical idea of the present invention, and the present invention is not limited thereto. In addition, the matters expressed in the attached drawings may be different from the actual implementation form in the schematic drawings to easily explain the embodiments of the present invention. In the specification, singular forms include plural forms, unless the context clearly states otherwise. As used in the specification, “comprises” and/or “comprising” means that a referenced element, step, operation and/or element precludes the presence of one or more other elements, steps, operations and/or elements. or does not rule out addition.

Hereinafter, embodiments will be clearly revealed through the accompanying drawings and descriptions of the embodiments. In the description of the embodiments, each layer (film), region, pattern or structure is formed “on” or “under” the substrate, each layer (film), region, pad or pattern. In the case where it is described, “on” and “under” include both being formed “directly” or “indirectly” through another layer. Additionally, the standards for the top or bottom of each floor are explained based on the drawing.

Figure 1 is a diagram showing the structure of a MEMS microphone package according to an embodiment of the invention.

Referring to Figure 1, the MEMS microphone package includes a base substrate 110 provided with an acoustic inlet 112 therein; A transducer 120 provided on the upper side of the base substrate 110 and converting the incoming sound into an electrical signal; A semiconductor unit 130 provided on the upper side of the base substrate 110 and electrically connected to the transducer 120 to amplify the electrical signal converted by the transducer 120; It includes a case 150 covering the transducer 120 and the semiconductor unit 130, and a member or means 161 disposed on the inner surface of the case 150 for absorbing or blocking external noise. Hereinafter, the member or means 161 for absorbing or blocking external noise will be described as a sound absorption means.

A device having a MEMS microphone package according to the present invention refers to a device with an acoustic function, such as a cell phone, recorder, headphone, headset, earphone, or microphone.

The base board 110 according to the present invention includes a printed circuit board (PCB), and may include, for example, a PCB made of a flexible material or a PCB made of a rigid material. The base substrate 110 may be made of various materials, and the shape and size of the base substrate 110 are not limited. It may have a circuit pattern on the top surface and/or inside of the base substrate 110 and be electrically connected to the semiconductor unit 130. The base substrate 110 has an acoustic inlet 112, and the acoustic inlet 112 is vertical from the outer surface of the base substrate 110 to the lower surface of the transducer 120 or the upper surface of the base substrate 110. It can be easily penetrated.

The transducer 120 detects vibration caused by sound and converts it into an electrical signal. As shown in FIG. 2, low-frequency noise mixed with a general acoustic signal (DC) may be introduced into the transducer 120.

The transducer 120 may be bonded to the upper surface of the substrate 110 using an adhesive such as a bond. The transducer 120 has a diaphragm 121 and a back plate 122 inside, and detects this vibration when the diaphragm vibrates due to external sound S1. I do it. The diaphragm 121 is formed of a membrane, and the back plate 122 may be an opposing electrode facing the diaphragm 121. The diaphragm 121 and the back plate 122 may be mounted on the surface of the MEMS substrate. The MEMS substrate has a hole 123 therein, and the hole 123 may be connected to or face the acoustic inlet 112. The transducer 120 may be disposed one or more on the base substrate 110.

The transducer 120 is electrically connected to the semiconductor unit 130 by a bonding wire 191 that functions as a wire and transmits an electrical signal due to vibration to the semiconductor unit 130. The semiconductor unit 130 may be connected to the base substrate 110 with a wire 193 or may be flip bonded.

The semiconductor unit 130 is an integrated circuit (IC) that receives the electrical signal generated by the transducer 120, amplifies and filters the electrical signal, and converts it into a usable electrical signal. For example, the semiconductor unit 130 may be an application specific integrated circuit (ASIC) manufactured to suit a specific purpose.

The transducer 120 and the semiconductor unit 130 are electrically connected with a wire 191. The encapsulant 135 seals the semiconductor unit 130 on the base substrate 110, protects the semiconductor unit 130 from moisture, and supports the wires 191 and 193. The encapsulant 135 may be spaced apart from the transducer 120 and from the inner surface of the case 150.

When external sound flows in through the sound inlet 112, the diaphragm 121 of the transducer 120 vibrates, and the capacitance changes according to the vibration. This small change in capacitance is amplified in the semiconductor unit 130 and converted into a usable electrical signal. Here, the back plate 122 disposed on the diaphragm 121 is connected to the semiconductor unit 130 with the wire 191 and serves as an electrode to transmit an electric signal by vibration to the semiconductor unit 130. It functions. Since the generation and conversion of electrical signals by the transducer 120 and the semiconductor unit 130 is a widely used technology in the relevant technical field, it can be omitted.

The case 150 includes a top portion 151 and a side portion 152, and the top portion 151 covers an upper area spaced apart from the transducer 120 and the semiconductor portion 130. The side portion 152 is bent from the upper surface portion 151 toward the upper surface of the base substrate 110 and covers side areas spaced apart from the outside of the transducer 120 and the semiconductor unit 130. The case 150 has an internal space 155, which is an echo space. The case 150 may be made of a metal material, and the internal space 155 may have a hexahedral shape.

The outer lower end of the case 150 may be bent outward from the upper surface of the base substrate 110. The upper surface of the base substrate 110 may be provided with a larger area than the lower surface of the case 150.

The sound absorption means 161 can prevent electrical distortion of the sound by blocking or absorbing the reflection of various electromagnetic noises (S2) generated from external electronic devices. The sound absorption means 161 may be attached to the entire inner surface of the case 150 or may be attached to a portion of the inner surface of the case 150.

When the sound absorption means 161 is attached to the entire inner surface area of the case 150, it may be formed on the entire inner surface of the upper surface portion 151 and the entire inner surface of the side portion 152.

When the sound absorbing means 161 is attached to a portion of the inner surface of the case 150, the inner surface of the upper surface 151 facing the base substrate 110 or the inner surface of the upper surface 151 and the upper surface portion It may be attached along the inner surface of the corner portion between (151) and the side portion (152).

Since the inner surface of the upper surface 151 facing the base substrate 110 includes an area facing the hole 123 of the transducer 120, it is an area where the incident or reflected amount of sound is the highest, so the sound absorption When the means 161 is attached, it is possible to effectively block or absorb a specific frequency band or external noise (S2).

The sound absorption means 161 may include a meta surface. As shown in FIG. 7, the metasurface can absorb or block a specific frequency band or external noise by adjusting each unit structure in a two-dimensional thin film structure into a nanolattice structure with atomic or molecule-sized cavities. The thickness of the meta surface may be λ/30 or less. Here, λ is the wavelength of the sound or noise frequency. In addition, when the thickness of the meta surface is within the above range, the sound absorption rate for external noise, that is, a specific frequency band, is 70% or more, for example, in the range of 70% to 80%, improving the noise blocking effect, and if it is less than the above range, the If the sound absorption rate is less than 70%, the noise blocking effect may be reduced.

This meta-surface functions as a micro Helmheltz resonator, absorbing and resonating a specific frequency (eg, S2) and canceling it out through interference. That is, the cavity resonates at a specific frequency and can absorb or block the specific frequency.

As another example, the sound-absorbing means 161 may provide a sound-absorbing structure in which a membrane is further attached to the lattice structure in order to absorb or block noise in a specific frequency band.

The sound absorption rate of the sound absorption means 161 absorbs or blocks low-frequency noise with a center frequency of 300 Hz, as shown in (A) of FIG. 8, and has a center frequency of 300 Hz and 400 Hz, as shown in (B) of FIG. 8. It can absorb or block low-frequency noise.

In the MEMS microphone package according to an embodiment of the invention, noise and howling due to noise reflection are not generated by the sound absorption means 161 disposed on the inner surface of the case 150, and thus the performance of sound detection can be improved. Additionally, since the sound absorbing means 161 is attached to the inner surface of the case 150, the installation space can be reduced.

3 to 6 show modified examples of sound absorption means in the MEMS microphone package according to an embodiment of the invention. The characteristics of the sound absorbing means will be referred to the above description.

As shown in FIG. 3 , the sound absorbing means 162 may be disposed on the lower surface of the base substrate 110 . The sound absorption means 162 may be disposed on the lower surface of the sound inlet 112 provided in the base substrate 110.

The sound absorption means 162 may have an area larger than that of the sound inlet 112 and may be attached to the bottom of the base substrate 110 . Since the sound absorption means 162 is located on the incident side of the sound inlet 112, it can reflect or absorb external noise from the outside of the base substrate 110. Since the sound absorption means 162 is located outside the hole 123 of the transducer 120, the inflow of external noise into the hole 123 can be blocked.

As shown in FIG. 4 , the sound absorbing means 164 may be disposed on the upper surface of the base substrate 110 . The sound absorption means 163 may be disposed on the upper surface of the sound inlet 112 provided in the base substrate 110. The sound absorption means 163 may be disposed at the bottom of the hole 123 of the transducer 120.

The sound absorption means 163 may have an area larger than the top surface area of the sound inlet 112 and may be attached to the top surface of the base substrate 110. Since the sound absorption means 163 is located on the output side of the sound inlet 112 or the lower surface of the transducer 120, external noise can be reflected or absorbed from the lower part of the transducer 120. Since the sound absorption means 163 is located at the bottom of the hole 123 of the transducer 120, the inflow of external noise into the hole 123 can be blocked.

As shown in FIG. 5 , the first sound absorption means 164 may be disposed on the side of the base substrate 110 . The first sound absorption means 164 may be disposed on the outer surface of the sound inlet 112A provided in the base substrate 110. The acoustic inlet 112A may extend from the side of the base substrate 110 to the bottom of the hole 123.

The first sound absorption means 164 may have an area larger than the outer surface area of the sound inlet 112 and may be attached to the side of the base substrate 110. Since the first sound absorption means 164 is located on the incident side of the sound inlet 112, it can reflect or absorb external noise from the outside of the base substrate 110. Since the first sound absorption means 164 is located outside the hole 123 of the transducer 120, it can block the inflow of external noise into the hole 123.

The second sound absorption means 165 may be disposed on all or part of the inner surface of the case 150.

The first and second sound absorption means 164 and 165 may reflect or absorb external noise having different low frequencies, for example, different center frequencies. Accordingly, the MEMS microphone package can provide a blocking effect from external noise in a wider band.

As another example, in the structures of FIGS. 3 and 4, the first and second sound absorbing means may be placed at different positions. For example, it can be placed on the inner surface of the case and the lower surface of the acoustic inlet, respectively, on the inner surface of the case and the upper surface of the acoustic inlet, or on the lower surface and upper surface of the acoustic inlet, respectively.

As another example, the sound absorbing means may be disposed between the diaphragm 121 and the back plate 122 of the transducer 120. As another example, the sound absorbing means may be disposed on the lower or upper surface of the diaphragm 121 of the transducer 120. This transducer 120 may be provided with sound absorption means therein.

As shown in FIG. 6, the sound absorbing means 151A may be implemented by a lattice structure having a cavity formed on the inner surface of the case 150. The sound absorption means 151A may be integrally formed inside the upper surface portion 151 of the case 150, or may be integrally formed on the inner surfaces of the upper surface portion 151 and the side portion 152. As the sound-absorbing means 151A is formed integrally with the inner surface of the case 150, the process of attaching a separate means for absorbing or blocking noise can be eliminated.

The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person with ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

In addition, although the above description has been made focusing on the examples, this is only an example and does not limit the present invention, and those skilled in the art will understand the above examples without departing from the essential characteristics of the present embodiment. You will be able to see that various modifications and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

110: base substrate
112: acoustic inlet
120: transducer
121: diaphragm
122: back plate
130: Semiconductor department
135: Encapsulation material
150: case
161,162,163,164,151A: sound absorbing means

Claims (12)

a base substrate having an acoustic inlet;
a transducer disposed on one side of the base substrate and disposed on an exit side of the sound inlet;
a semiconductor portion disposed on the other side of the base substrate and electrically connected to the transducer;
a case disposed on the base substrate and having an internal space to protect the transducer and the semiconductor unit; and
A MEMS microphone package disposed on the inner surface of the case and including sound absorption means for blocking or absorbing external noise. According to claim 1,
The sound inlet is a MEMS microphone package that penetrates from the bottom of the base substrate to the bottom of the transducer. According to claim 1,
The sound inlet is a MEMS microphone package connected to the bottom of the transducer from the side of the base substrate. According to any one of claims 1 to 3,
A MEMS microphone package in which the sound absorption means is a meta surface. According to clause 4,
A MEMS microphone package where the thickness of the meta surface is λ/30 or less, and λ is the wavelength of noise. a base substrate having an acoustic inlet;
a transducer disposed on one side of the base substrate and disposed on an exit side of the sound inlet;
a semiconductor portion disposed on the other side of the base substrate and electrically connected to the transducer;
a case disposed on the base substrate and having an internal space to protect the transducer and the semiconductor unit; and
A MEMS microphone package disposed on the outer or inner surface of the base substrate and including a first sound absorption means for blocking or absorbing external noise. According to clause 6,
The acoustic inlet is disposed on the bottom or side of the base substrate to be connected to the internal hole of the transducer,
The first sound absorption means is disposed on the incident side of the sound inlet and attached to the outer surface of the base substrate. According to clause 6,
The acoustic inlet is disposed on the bottom or side of the base substrate to be connected to the internal hole of the transducer,
The MEMS microphone package wherein the first sound absorption means is disposed on an emission side of the sound inlet and attached to the upper surface of the base substrate. According to any one of claims 6 to 8,
The MEMS microphone package wherein the first sound absorption means is a meta surface. According to clause 9,
The thickness of the meta surface is λ/30 or less, λ is the wavelength of noise,
A MEMS microphone package in which the meta surface has a sound absorption rate of 70% or more. According to any one of claims 6 to 8,
It includes a second sound absorbing means disposed on the inner surface of the case,
A MEMS microphone package in which the first and second sound absorption means absorb or block external noise having different center frequencies. According to any one of claims 6 to 8,
A MEMS microphone package further comprising an encapsulant that seals the semiconductor unit.

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