MEMS transducers and microphone components

Abstract

Microelectromechanical system transducer and microphone assembly. A microelectromechanical system (MEMS) transducer for integration in a microphone assembly is provided, the MEMS transducer being designed to generate a thermally generated acoustic signal. The MEMS transducer generally comprises: a substrate having a hole, a transducing component at least partially located above the hole and coupled to the substrate, an electrical contact coupled to the transducing component, and a resistor integrated with the substrate or the transducing component. The resistor is coupled to an electrical contact electrically isolated from the contacts of the MEMS transducer or the transducing component. The transducing component comprises an insulating material coupled to the substrate. The transducing component comprises a fixed electrode and a movable electrode at least partially located above the hole of the substrate. The fixed electrode or the movable electrode is formed on the insulating material. The resistor may be formed on the insulating material or suspended from the insulating material.

Description

Technical Field

[0001] The present invention relates to a micro-electromechanical system (MEMS) sensor, and in particular, to a MEMS sensor having resistors disposed on the same substrate. Background Art

[0002] Microphone assemblies including microelectromechanical systems (MEMS) acoustic transducers convert acoustic energy into electrical signals. Microphone assemblies may be employed in mobile communication devices, laptop computers, and appliances, among other devices and machinery. An important parameter of a microphone assembly is the acoustic signal-to-noise ratio (SNR), which compares the desired signal level (e.g., the signal amplitude due to acoustic interference captured by the microphone assembly) to the background noise level. The signal-to-noise ratio may be used to determine the functional status of the microphone assembly. Summary of the invention

[0003] One aspect of the present invention relates to a micro-electromechanical system transducer for integration in a microphone assembly, the microphone assembly having a housing, the micro-electromechanical system transducer being arranged in the housing, the micro-electromechanical system transducer comprising: a substrate comprising a hole; an electroacoustic transducing component, the electroacoustic transducing component being at least partially located above the hole and connected to the substrate; an electrical contact, the electrical contact being connected to the micro-electromechanical system transducer; and a resistor, the resistor being connected to an electrical contact electrically isolated from the electrical contact of the micro-electromechanical system transducer.

[0004] Another aspect of the present invention relates to a microphone assembly, which includes: a shell, the shell including an acoustic port and a surface-mountable electrical interface; an acoustic transducer, the acoustic transducer being disposed in the shell, the acoustic transducer having electrical contacts; a resistor, the resistor being disposed in the shell, the resistor having electrical contacts electrically isolated from the electrical contacts of the acoustic transducer; and an integrated circuit, the integrated circuit being disposed in the shell and electrically connected to the resistor, the acoustic transducer and the electrical interface, wherein the integrated circuit is configured to: apply power to the resistor; and detect an acoustic signal generated by the acoustic transducer in response to detecting a pressure change in the shell, the pressure change in the shell being caused by heat generated by the resistor when power is applied.

[0005] Yet another aspect of the present invention relates to a microphone assembly, comprising: a shell having a thermally and electrically conductive acoustic port and a surface-mountable electrical interface; an acoustic transducer disposed within the shell, the acoustic transducer having electrical contacts; and an annular resistor formed by a resistive film disposed around the acoustic port, the annular resistor having at least one electrical contact, the at least one electrical contact being configured to receive electrical power from a device to drive the annular resistor to generate resistive heat in the acoustic port. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The foregoing and other features of the present invention will become more fully apparent from the following description in conjunction with the accompanying drawings and the appended claims. The accompanying drawings depict only a few embodiments according to the present invention and should not be considered as limiting the scope thereof. Below, various embodiments are described in more detail in conjunction with the accompanying drawings.

[0007] Figure 1 is a schematic diagram of potential resistor locations in a microphone assembly according to an exemplary embodiment;

[0008] Figure 2 is a schematic diagram of an exemplary MEMS transducer having a free plate diaphragm and an air-insulated suspended resistor according to a first exemplary embodiment;

[0009] Figure 3 is a schematic diagram of an exemplary MEMS transducer having a free plate diaphragm and an air-insulated suspended resistor according to a second exemplary embodiment;

[0010] FIG. 4A to FIG. 4B is a schematic diagram of an exemplary MEMS transducer having a constrained diaphragm and an air-insulated suspended resistor according to a third exemplary embodiment;

[0011] Figure 5 is based on Figure 2 A three-dimensional diagram of an exemplary MEMS transducer of an embodiment of the present invention;

[0012] Figure 6 is based on Figure 3 A three-dimensional diagram of an exemplary MEMS transducer of an embodiment of the present invention;

[0013] Figure 7 is a graph illustrating resistor sensitivity versus frequency for the entire range of the audio frequency band; and

[0014] FIG. 8A to FIG. 8B A schematic diagram showing a microphone assembly and resistor combination according to a fourth exemplary embodiment; and

[0015] Fig. 9is a schematic diagram of an exemplary MEMS transducer with a constrained diaphragm. DETAILED DESCRIPTION

[0016] The accompanying drawings cited in the following description schematically illustrate the embodiments. For the sake of clarity, the proportions, distances, positional relationships, etc. of the components may be exaggerated, and the illustration of a portion of the components may be omitted. In the following description, the same name or reference numeral generally represents the same component or a component made of the same material, and its repeated detailed description will be omitted when appropriate.

[0017] Generally, a microelectromechanical system (MEMS) transducer for integration in a microphone assembly is disclosed herein, the MEMS transducer being designed to generate a thermally generated acoustic signal. The MEMS transducer generally comprises: a substrate having a hole, an electroacoustic transducing component at least partially located above the hole and coupled to the substrate, an electrical contact coupled to the transducing component, and a resistor integrated with the substrate or the transducing component. The resistor is coupled to an electrical contact electrically isolated from the contacts of the MEMS transducer or the transducing component. The transducing component comprises an insulating material coupled to the substrate. The transducing component is a variable capacitor comprising a fixed electrode and a movable electrode at least partially located above the hole of the substrate. The fixed electrode or the movable electrode is formed on the insulating material. The resistor may be formed on the insulating material or suspended from the insulating material.

[0018] According to some embodiments described herein, a microphone assembly designed to generate a thermally generated acoustic signal includes: a MEMS acoustic transducer, an integrated circuit, a substrate, a cover, and an insulated resistor. The microphone device generally includes a MEMS transducer and an integrated circuit disposed in an internal volume of a housing, the housing having an acoustic port and an electrical interface suitable for integration with a host device (e.g., using surface mounting technology). In one implementation, the housing includes a cover disposed on a substrate or base, the combination of which forms an internal volume, in which a transducer and an integrated circuit are disposed. The MEMS transducer may be a capacitive transducer, a piezoelectric transducer, or other transducer configured to convert acoustic energy into an electrical signal. The MEMS transducer is coupled to an integrated circuit, and the integrated circuit is coupled to contacts on the electrical interface. The integrated circuit is capable of receiving and regulating the electrical signal generated by the transducer. Such signal conditioning may include: buffering, filtering, amplification, A / D conversion, protocol interface conversion, and other signal conditioning or processing. The integrated circuit may be an application specific integrated circuit (ASIC). In some embodiments, the MEMS transducer is coupled to an acoustic port formed on a substrate and is located near the acoustic port. In other embodiments, the transducer is coupled to and located proximate to an acoustic port disposed in a cover or lid portion of the housing.

[0019] Heating of the back volume between the substrate and cover of the microphone device can generate acoustic waves, resulting in ambient noise. Various embodiments disclosed herein can increase the functionality and application of MEMS microphones and transducers by exploiting design aspects that were previously considered drawbacks. In most microphone devices, the acoustic or ambient noise generated by the device can negatively impact the quality of the sound being recorded, particularly due to the proximity of the signal to the microphone itself. Internally generated acoustic noise is generally considered undesirable because it is difficult to control and mixes with any external ambient noise that affects the signal. However, if the generation of acoustic noise can be controlled by an integrated circuit, then the noise can be generated in a purposeful manner. Among other benefits, controllable acoustic signals within a MEMS microphone device can enable the device to be used in self-test applications and noise cancellation. By reference Figures 1 to 7 , details of the apparatus designed to perform this function are more fully described.

[0020] exist Figure 1 In the present invention, microphone assembly 100 includes a substrate and a cover, which form an enclosed volume in which an integrated circuit and a MEMS transducer are disposed. In order to generate acoustic stimulation at the device level, a heat source must be placed within the enclosed volume of the microphone device. The heat source must be small, power efficient, and limited in cost and complexity. In this embodiment, a resistor is used as the heat source, but it should be appreciated that another heat source with similar functionality will also suffice. A resistor is a basic heat generator that can be controlled by the size of the resistor and the amount of current supplied to the resistor. In order to achieve the highest efficiency and control of the heat source, the resistor is preferably air-insulated and must be thermally coupled to the air in the enclosed volume. Four potential locations for the resistor are identified in the enclosed volume of the microphone assembly: on the substrate (102), on the integrated circuit (104), within the base substrate (106), and on the MEMS die (108).

[0021] Position 102 on the substrate requires free substrate space for the footprint of the resistor to be mounted within the enclosed volume, limiting the ability to further reduce size. Position 102 also increases manufacturing costs because a third component must be added to the substrate before the cover or lid is added. Position 104 on the integrated circuit results in poor thermal connection to the enclosed volume because the resistor will be encapsulated in the interlayer dielectric layer. Position 104 will also increase the size of the integrated circuit. Position 106 within the base substrate also results in poor thermal connection to the enclosed volume due to sealing the base substrate during manufacturing (e.g., using FR-4 and solder mask). Position 108 on the MEMS die does not occupy as much space as position 102 due to exposing the MEMS die to air in the enclosed back cavity volume, and unlike positions 104 and 106, has good thermal connection. Position 108 allows the resistor to be electrically isolated from the transducer by relying on a manufacturing process that provides electrically isolated conductive structures; this manufacturing process provides further flexibility in the design of both the resistor and the transducer.

[0022] Figure 2 2 is a schematic diagram of a MEMS die 200 having an electroacoustic transducer component and a resistor according to a first embodiment. The MEMS die 200 includes a substrate 202, an electroacoustic transducer component (transducer) 204, and a resistor 206. Figure 2 , the transducer 204 includes a diaphragm 208 and a backplate 210, wherein the diaphragm is oriented parallel to the backplate and is configured to move relative to the backplate in response to changes in pressure received through an acoustic port 212. The transducer 204 is at least partially mounted above the acoustic port 212. Alternatively, the transducer 204 may be different from a capacitive device, and the transducer may be mounted on a lid or cover (not shown) rather than on a base as described herein. The transducer 204 may generate an electrical signal that can be detected by an integrated circuit (not shown) in response to movement of the diaphragm. The transducer 204 may include electrical contacts coupled to the integrated circuit, and the integrated circuit may be programmed to receive and process the electrical signal generated by the transducer 204. The integrated circuit may be an application specific integrated circuit (ASIC) or other type of programmable system on a chip.

[0023] The resistor 206 may be an air-insulated resistor manufactured similarly to the diaphragm 208 in order to maintain the existing manufacturing sequence. In the illustrated embodiment, the insulating material 214 is coupled to the substrate 202. The resistor 206 may be formed using the same material as the diaphragm and may be suspended from the insulating material using a tab 216. The resistor is integrated with the substrate 202 or the transducer 204 and is electrically isolated from the transducer 204. The resistor 206 is coupled to electrical contacts that interface with the integrated circuit.

[0024] The integrated circuit can be programmed to use the thermoacoustic relationship to drive a current through the resistor 206 to heat the enclosed volume, thereby generating a known acoustic signal that can be detected by the transducer 204. The known acoustic signal is then incident on the diaphragm 208 and generates an electrical signal representative of the acoustic signal. The integrated circuit can be programmed to analyze the electrical signal to determine the state of the transducer, such as a blocked state, an inoperable state, or an operable state, based on the frequency response of the detected signal. The integrated circuit can also be programmed to detect ambient noise from the incoming acoustic signal and drive a current through the resistor to generate a thermally induced acoustic signal to cancel the ambient noise.

[0025] Figure 3 is a schematic diagram of a MEMS die 300 having an electroacoustic transducing component and a resistor according to a second embodiment. The MEMS die 300 includes: a substrate 202, an electroacoustic transducing component (transducer) 204, and a resistor 306. The resistor 306 is an air-insulated resistor manufactured similarly to the backplate 210 in order to maintain the existing manufacturing sequence. In this embodiment, the insulating material 214 is connected to the substrate 202. The resistor 306 is made of the same material as the backplate and is formed on the insulating material 214. The resistor can be integrated with the substrate 202 or the transducer 204 and is electrically isolated from the transducer 204. The integrated circuit can be programmed to operate similarly to the reference Figure 2 In the manner described, current is driven through resistor 306 and a known acoustic signal is generated, which is then used to evaluate the state of transducer 204 and / or to detect and / or cancel ambient noise in the incoming signal.

[0026] FIG. 4A to FIG. 4B Schematic diagram of a MEMS die 400 with an electroacoustic transducer component and a resistor according to a third embodiment. The MEMS die 400 includes a substrate 202, an electroacoustic transducer component (transducer) 404, and a resistor 306. Figure 4A In FIG. 4 , the transducer 404 has a movable electrode (diaphragm) 408 and a fixed electrode (backplate) 410, wherein the diaphragm is oriented parallel to the backplate. An electrical signal representing the acoustic stimulus may be generated and transmitted to an integrated circuit for processing via electrical contacts 414a and 414b, such as in FIG. Figure 4B. The transducer 404 is at least partially mounted above the acoustic port 212. Alternatively, the transducer 404 may be mounted on a flap or cover (not shown) rather than on a base as described herein. The transducer 404 may generate an electrical signal detectable by an integrated circuit (not shown) in response to movement of the diaphragm. In some embodiments, the backplate 410 in the transducer 404 may not be present, and the diaphragm 408 is constructed using a piezoelectric material. The electrical signal is generated due to the mechanical strain in the piezoelectric layer (which is caused by the deflection caused by the incident sound pressure). The integrated circuit can be connected to the transducer 404 via electrical contacts 414a to 414b, and the integrated circuit can be programmed to receive and process the electrical signals generated by the transducer 404. The integrated circuit can be an application specific integrated circuit (ASIC) or other type of programmable system on a chip. The integrated circuit can be programmed to operate similarly to the reference Figure 2 In the manner described, a drive current flows through resistor 306 via electrical contact 416 and generates a known acoustic signal, which is then used to evaluate the state of transducer 404 and / or to detect and / or cancel ambient noise in the incoming signal.

[0027] Figure 5 is based on Figure 2 A three-dimensional reproduction of a MEMS transducer 500 with an integrated resistor according to an embodiment of the present invention. The MEMS transducer 500 includes a substrate 502, a microphone 504 mounted on the substrate, and a suspended resistor 514. The microphone 504 includes a backplate electrode layer 506, a backplate structural layer 508, and a diaphragm 510 oriented parallel to each other. The diaphragm 510 moves freely relative to the backplate electrode layer 506 in response to pressure changes, and is positioned within a set of peripheral posts 512 arranged around the circumference of the diaphragm 510, the set of peripheral posts 512 protruding from the backplate structural layer 508. The substrate 502 can be connected to an insulating layer 516. The resistor 514 is formed as follows: the resistor is suspended from the insulating layer 516, and the resistor 514 is formed of the same material as the diaphragm.

[0028] Figure 6 is based on Figure 3A three-dimensional reproduction of a MEMS transducer 600 with an integrated resistor according to an embodiment of the present invention. The MEMS transducer 600 includes: a substrate 502, a microphone 604 mounted on the substrate, and a suspended resistor 616. The microphone 604 includes a backplate electrode layer 506, a backplate structural layer 508, and a diaphragm 510 oriented parallel to each other. The diaphragm 510 is configured to move relative to the backplate electrode layer 506 in response to pressure changes. The diaphragm 510 is suspended from a central column 614 and positioned within a set of peripheral columns 512 arranged around the circumference of the diaphragm 510, and the set of peripheral columns 512 protrude from the backplate structural layer 508. The substrate 502 can be connected to an insulating layer 618. The resistor 616 is formed within the insulating layer 618 and has the same material as the backplate electrode layer 506.

[0029] It should be appreciated that the various embodiments described herein are not limited to Figures 2 to 6 For example, the MEMS die may include reference Figures 2 to 6 Any combination of the resistors or transducers described. Moreover, the transducers and resistors can be formed of the same material or different materials depending on the manufacturing process used and the design requirements.

[0030] Figure 7is a graph illustrating the relationship between resistor sensitivity and frequency for the entire range of the audio frequency band. The graph depicts the entire range of the audio frequency band that can be detected by humans from 20 Hz to 20 kHz, and the entire range is divided into two regions: region 701 from 20 Hz to 2 kHz, and region 702 from 2 kHz to 20 kHz. The acoustic connection between the resistor and the air dominates the frequency band spanned by region 701, while the electrical connection between the resistor and the integrated circuit dominates the frequency band spanned by region 702. Region 701 covers the frequency range (2 Hz to 2 kHz) in which a sufficiently sensitive resistor can generate an acoustic signal that is detectable by the human ear. When someone speaks into the microphone (such as during a telephone conversation), the acoustic signal generated is in the usable voice frequency range of about 300 Hz to 3400 Hz, and the phone further relies on harmonics of the lower fundamental frequency in this range to generate aliased signals that can be heard throughout the range. Therefore, any ambient noise detected at the microphone will be transmitted as part of the acoustic signal. However, any signal from 20 Hz to 2 kHz (and any aliases thereof) can be cancelled by the thermally generated acoustic signal from the resistor, effectively canceling the ambient noise to produce a smoother acoustic signal. The integrated circuit can be programmed to identify the frequency of the ambient noise detected at the transducer element and drive current to the resistor to produce a frequency at which the aliased harmonic signals effectively cancel each other. The current range of this embodiment allows noise cancellation for most sounds entering the microphone that are easily discernible by the human ear.

[0031] FIG. 8A to FIG. 8B A microphone assembly and resistor combination according to a fourth embodiment and a specific use case is illustrated. Fig. 8A 800 is a cross-sectional view of a microphone assembly 800 including a MEMS transducer 802 mounted on a base 804 at least partially above an acoustic port 806 filled with water (or other liquid) 808 after a liquid ingress event. The water 808 prevents sound from properly penetrating the acoustic port 806 to approach the acoustic transducer 802. The base 804 may be a printed circuit board or other surface mountable electrical interface. The acoustic port 806 is a thermally and electrically conductive acoustic port, such as a plated via. The acoustic port 806 may be cylindrical in shape and extend through the base 804 to the bottom surface of the base. The bottom surface of the base 804 has a solder ring ground 810 mounted thereon, to which the conductive acoustic port 806 is electrically coupled. A solder resist ring 812 acts as an insulator on the bottom surface of the base 804 and acts as an insulator between the conductive acoustic port 806 and the MEMS transducer 802.

[0032] The annular resistive heating element (resistor) 814 is disposed around the acoustic port in the form of a ring of conductive material. The resistor 814 may completely or partially surround the circumference of the acoustic port 806. The resistor 814 may be composed of concentric rings of resistive film 816, external copper pads 818 connected to the integrated circuit, and internal copper pads 820 connected to the acoustic port 806. Alternatively, the resistor 814 may be a concentric ring that connects the acoustic port 806 to the internal copper pad 820. Figure 1 The integrated circuit can apply power to the resistor 814 to generate heat. The heat generated by the resistor can be conducted through the acoustic port 806 to heat the water 808 trapped in the acoustic port. The applied heat increases the temperature of the water in the acoustic port, thereby enhancing the latent heat of evaporation of the liquid water and increasing the pressure of the air inside the microphone assembly. The pressurized air acts to push the water out of the acoustic port 806, effectively cleaning the microphone and restoring the assembly to full function.

[0033] In some embodiments, the diaphragm in the acoustic transducer can also be used as a heating element, which functions similarly to the annular resistive heating element 814. Fig. 9 As shown, by using a second electrical contact 414c for the diaphragm in the acoustic transducer, the integrated circuit can be configured to pass current through the diaphragm between contact 414a and contact 414c, thereby causing resistive heating of the diaphragm. The high temperature of the diaphragm can help evaporate any liquid that is trapped in the acoustic port and in contact with the diaphragm.

[0034] In some embodiments, a ring resistor may also be used to keep the MEMS die attach softer during exposure to cold ambient temperatures. When the microphone assembly is exposed to extremely cold temperatures, the MEMS die attach may stiffen and the use of the microphone may contribute to packaging stresses on the MEMS die. In some embodiments, a temperature sensor may be added within the back volume of the microphone assembly to sense the ambient temperature within the microphone package. The temperature sensor is coupled to an integrated circuit that is programmed to supply power to the ring resistor. When the temperature within the microphone assembly drops below a predetermined threshold (e.g., 0 degrees Celsius), the integrated circuit is programmed to supply power to the ring resistor to heat the MEMS die attach to which it is connected, such as in Fig. 8A Resistive heating of the MEMS die is to reduce stress on the MEMS attachment and can mitigate performance changes or prevent damage due to stress. The integrated circuit can be programmed to supply current to the ring resistor at the microphone component level or system level. For example, an integrated circuit within the microphone component can be connected to a temperature sensor and the integrated circuit can be programmed to control the ring resistor.

[0035] The foregoing implementations require more circuitry on the integrated circuit and additional space on the base of the printed circuit board to accommodate the additional electrical connection pads. In some implementations, rather than including a temperature sensor within the microphone package and using an integrated circuit to drive the resistor, the resistor control and / or drive circuitry can be implemented external to the microphone package, such as within a host device. For example, a host device (such as a phone, tablet, recording device, etc.) can include circuitry / functionality such as utilizing a local temperature sensor and an integrated circuit to control a ring resistor. The integrated circuit is programmed to control the microphone assembly within the system, and less circuitry is required because the integrated circuit can utilize the resistor's electrical contacts 416 for thermal control.

[0036] It should be appreciated that although the concepts herein are presented as separate embodiments, elements of the embodiments described herein may be combined to obtain combinations of features not explicitly exemplified. For example, a ring resistor may be combined with a Figures 2 to 6 Furthermore, the embodiments described herein are not limited to a single resistor and may include Figure 8B The ring resistor is also connected with Figures 2 to 6 The embodiment of the present invention can be combined with any of the resistors disclosed in the resistor embodiment, so that the embodiment includes two resistors for alternative purposes. In this case, the electrically isolated electrical contact set 416 for the resistor is present on the MEMS tube core, and the external copper pad 818 or electrode for the ring resistor is present in the printed circuit board base.

[0037] According to some embodiments, a microelectromechanical system (MEMS) transducer for integration in a microphone assembly is disclosed, the microphone assembly having a housing in which the transducer is housed, the transducer comprising: a substrate comprising a hole; an electroacoustic transducing component at least partially located above the hole and connected to the substrate; an electrical contact connected to the transducer; and a resistor connected to an electrical contact electrically isolated from the electrical contact of the transducer.

[0038] In some embodiments, the transducing component may include an insulating material coupled to a substrate, the resistor being formed on the insulating material. The substrate may have a mounting surface and a surface opposite to the mounting surface. The insulating material formed with the resistor is coupled to the surface of the substrate opposite to the mounting surface. The resistor may be laterally offset relative to the hole of the substrate. The transducing component may be a variable capacitor, the variable capacitor including a fixed electrode and a movable electrode at least partially located above the hole of the substrate. At least one of the fixed electrode or the movable electrode may be formed on the insulating material. The movable electrode may be positioned between the substrate and the fixed electrode.

[0039] In some embodiments, the resistor is suspended from an insulating material. The substrate may have a mounting surface and a surface opposite to the mounting surface. The insulating material (from which the resistor is suspended) may be coupled to the surface of the substrate opposite to the mounting surface. The resistor may be laterally offset relative to the hole of the substrate. The transducer component may be a variable capacitor comprising a fixed electrode and a movable electrode at least partially located above the hole of the substrate. At least one of the fixed electrode or the movable electrode may be formed on an insulating material. The movable electrode may be positioned between the substrate and the fixed electrode. The transducer may be a variable capacitor comprising a fixed electrode and a movable electrode at least partially located above the hole of the substrate, wherein at least one of the fixed electrode or the movable electrode is formed on the insulating material.

[0040] According to some embodiments, a microphone assembly is provided, the microphone assembly comprising: a housing having an acoustic port and a surface-mountable electrical interface; an acoustic transducer disposed within the housing, the transducer having electrical contacts; a resistor disposed within the housing, the resistor having electrical contacts electrically isolated from the electrical contacts of the transducer; and an integrated circuit disposed within the housing and electrically coupled to the resistor, the transducer, and the electrical interface. The integrated circuit can be configured to apply power to the resistor and detect an acoustic signal generated by the transducer in response to detecting a pressure change within the housing due to heat generated by the resistor when power is applied.

[0041] In some embodiments, a resistor can be integrated with an acoustic transducer. The acoustic transducer is a microelectromechanical system (MEMS) transducer, the MEMS transducer includes a substrate having a hole acoustically coupled to an acoustic port, and the transducer can be coupled to the substrate and can be positioned at least partially above the hole. The transducer can be formed on an insulating material, which is coupled to the substrate. The resistor can be formed on an insulating material. The substrate can include a mounting surface fastened to a housing and a surface opposite to the mounting surface. The transducer and the insulating material formed with the resistor can be coupled to the surface of the substrate opposite to the mounting surface. The resistor can be laterally offset relative to the hole of the substrate. The transducer can be a variable capacitor, the variable capacitor including a fixed electrode and a movable electrode at least partially located above the hole of the substrate, wherein, at least one of the fixed electrode or the movable electrode is formed on an insulating material. The movable electrode can be positioned between the substrate and the fixed electrode.

[0042] In some embodiments, the microphone assembly includes a ring resistor formed by a resistive film disposed around an acoustic port. The ring resistor includes an electrical contact pad coupled to the acoustic port. The electrical contact pad may be an extension of the acoustic port, or an internal copper pad for coupling to the acoustic port. The acoustic port may be thermally and electrically conductive. The ring resistor includes an electrode electrically coupled to an integrated circuit. The integrated circuit is configured to apply power to the electrode to generate resistive heat in the acoustic port; the heat is then thermally transferred through the entire acoustic port. The ring resistor may be mounted on a surface-mountable electrical interface of the microphone assembly, or the ring resistor may be embedded in a surface-mountable electrical interface. In some embodiments, a diaphragm in an acoustic transducer is used as a resistive heating component, wherein the diaphragm includes two separate electrical contacts coupled to an integrated circuit. The integrated circuit is configured to apply power to the diaphragm to generate resistive heat on a surface of the diaphragm. In some embodiments, the resistor coupled to the transducer is a ring resistor. In some embodiments, the resistor coupled to the transducer is the diaphragm itself. In some implementations, the microphone assembly includes both a resistor coupled to the transducer and a ring resistor disposed around the acoustic port.

Claims

1. A micro-electromechanical system transducer, wherein the micro-electromechanical system transducer is integrated in a microphone assembly, wherein the microphone assembly has a housing, wherein the micro-electromechanical system transducer is arranged in the housing, and wherein the micro-electromechanical system transducer comprises: a substrate, the substrate comprising a hole; an electroacoustic transducer component, the electroacoustic transducer component being connected to the substrate; an electrical contact coupled to the MEMS transducer; as well as a resistor coupled to an electrical contact electrically isolated from an electrical contact of the MEMS transducer, wherein the electroacoustic transducer component is a variable capacitor, the variable capacitor comprising a fixed electrode and a movable electrode at least partially located above the hole of the substrate, the fixed electrode and the movable electrode being located on different layers of the micro-electromechanical system transducer, and The resistor is located on the same layer as the fixed electrode or the movable electrode, and the resistor includes the same material as the fixed electrode or the movable electrode.

2. The MEMS transducer according to claim 1, wherein: The electroacoustic transducing component includes an insulating material coupled to the substrate, and the resistor is formed on the insulating material.

3. The MEMS transducer according to claim 2, wherein: The substrate has a mounting surface and a surface opposite to the mounting surface, and the insulating material on which the resistor is formed is coupled to the surface of the substrate opposite to the mounting surface.

4. The MEMS transducer according to claim 3, wherein: The resistor is laterally offset relative to the hole of the substrate.

5. The MEMS transducer according to claim 1, wherein: The movable electrode is located between the substrate and the fixed electrode.

6. The MEMS transducer according to claim 1, wherein: The electroacoustic transducing component includes an insulating material coupled to the substrate, the resistor being suspended from the insulating material.

7. The MEMS transducer according to claim 6, wherein: The substrate has a mounting surface and a surface opposite to the mounting surface, and the insulating material is coupled to the surface of the substrate opposite to the mounting surface.

8. The MEMS transducer according to claim 7, wherein: The resistor is laterally offset relative to the hole of the substrate.

9. The MEMS transducer according to claim 8, wherein: The movable electrode is located between the substrate and the fixed electrode.

10. A microphone assembly, comprising: a housing including an acoustic port and a surface-mountable electrical interface; The MEMS transducer according to any one of claims 1 to 9, wherein the MEMS transducer is arranged in the housing; and an integrated circuit disposed in the housing and electrically coupled to the resistor and the electrical interface, Wherein, the integrated circuit is configured as: applying power to the resistor; and An acoustic signal generated by the micro-electromechanical system transducer is detected in response to detecting a pressure change within the housing due to heat generated by the resistor when power is applied.

11. The microphone assembly according to claim 10, wherein: The integrated circuit is configured to: receiving a temperature measurement from a temperature sensor; determining that the temperature measurement result is below a predetermined threshold; as well as Electrical power is applied to electrical contacts coupled to the resistor to generate resistive heat.

12. The microphone assembly according to claim 10 or 11, wherein: The integrated circuit is configured to: applying power to the resistor, and An acoustic signal generated by the micro-electromechanical system transducer is detected in response to detecting a pressure change within the housing due to heat generated by the resistor when power is applied.

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