PATENT DOCUMENT

Publication Number: US-9661411-B1
Application Number: US-201615005908-A
Country: US
Kind Code: B1

Title: Integrated MEMS microphone and vibration sensor

Abstract:
MEMS microphone and vibration sensor dies and packages are described. In an embodiment, a MEMS microphone and vibration sensor die includes a die substrate, a MEMS microphone on the die substrate and a MEMS vibration sensor on the die substrate. The MEMS vibration sensor may include a plurality of beams with different proof masses corresponding to different resonant frequencies, wherein the different proof masses comprise a same material as the die substrate.

Claims:
What is claimed is: 
     
       1. A micro-electro-mechanical systems (MEMS) microphone and vibration sensor die comprising:
 a die substrate; 
 a MEMS microphone on the die substrate; and 
 a MEMS vibration sensor on the die substrate, the MEMS vibration sensor having a plurality of beam transducers, each of the plurality of beam transducers having a beam and a proof mass, wherein each proof mass is tuned to a different resonant frequency range and comprises a same material as the die substrate. 
 
     
     
       2. The MEMS microphone and vibration sensor die of  claim 1  wherein each beam comprises a same length dimension. 
     
     
       3. The MEMS microphone and vibration sensor die of  claim 1  wherein at least one proof mass comprises a different length dimension than another proof mass. 
     
     
       4. The MEMS microphone and vibration sensor die of  claim 1  wherein the MEMS microphone comprises a diaphragm, and the diaphragm comprises a same material as each beam. 
     
     
       5. The MEMS microphone and vibration sensor die of  claim 1  wherein the MEMS vibration sensor is operable to detect mechanical vibrations within a frequency range of from 20 Hz to 20 kHz. 
     
     
       6. The MEMS microphone and vibration sensor die of  claim 1  wherein the plurality of beam transducers comprise a first beam transducer and a second beam transducer, wherein the first beam transducer is operable to detect a mechanical vibration in a first frequency range and the second beam transducer is operable to detect a mechanical vibration within a second frequency range, wherein the first frequency range is different than the second frequency range. 
     
     
       7. The MEMS microphone and vibration sensor die of  claim 1  wherein the MEMS microphone and the MEMS vibration sensor are integrally formed with the die substrate as one integrally formed unit, and the integrally formed unit is mounted to a package substrate. 
     
     
       8. The MEMS microphone and vibration sensor die of  claim 1  wherein the MEMS microphone and vibration sensor die is incorporated into a remote control housing for a headphone. 
     
     
       9. A headphone remote controller having multiple sensors, the headphone remote controller comprising:
 a housing for a remote controller of a headphone, the housing having a housing wall defining a vibration contact side for the remote controller; 
 a multiple sensor package positioned within the housing, the multiple sensor package comprising a micro-electro-mechanical systems (MEMS) microphone, a plurality of MEMS beam transducers having different proof masses corresponding to different resonant frequencies, and an application-specific integrated circuit (ASIC) electrically connected to the MEMS microphone and the MEMS beam transducers; 
 a printed circuit board (PCB) positioned within the housing, wherein the multiple sensor package is mounted to the PCB; and 
 a capacitive contact sensor mounted to the wall defining the vibration contact side for the remote controller. 
 
     
     
       10. The headphone remote controller of  claim 9  wherein the multiple sensor package is mounted to a side of the PCB facing the vibration contact side for the remote controller. 
     
     
       11. The headphone remote controller of  claim 9  wherein the different proof masses are connected to a plurality of beams, and each of the beams have a same length dimension. 
     
     
       12. The headphone remote controller of  claim 9  wherein the MEMS microphone and the plurality of beam transducers are integrally formed with a die substrate as a single integrally formed unit, and the single integrally formed unit is mounted to a package substrate. 
     
     
       13. The headphone remote controller of  claim 9  wherein the MEMS microphone is connected to a first die substrate and the plurality of beam transducers are connected to a second die substrate, and wherein the first die substrate and the second die substrate are separately mounted to the package substrate. 
     
     
       14. The headphone remote controller of  claim 9  wherein the MEMS microphone is operable to sense air pressure changes corresponding to a first frequency range and the plurality of beam transducers are operable to sense mechanical vibrations corresponding to a second frequency range. 
     
     
       15. The headphone remote controller of  claim 9  wherein the capacitive contact sensor comprises a pattern of contacts operable to detect a contact between the housing and a user. 
     
     
       16. The headphone remote controller of  claim 15  wherein a width of the contact with respect to the pattern of contacts is used to differentiate between a first contact indicating a user is using the remote controller to control the headphone and a second contact indicating the user is sensing a vocal cord vibration through the user&#39;s skin. 
     
     
       17. A method of manufacturing a micro-electro-mechanical systems (MEMS) microphone and vibration sensor die, the method comprising:
 providing a substrate; and 
 forming a MEMS microphone and a MEMS vibration sensor from the substrate, the MEMS microphone having a diaphragm and a top plate suspended over a first opening in the substrate, and the MEMS vibration sensor having a plurality of beam transducers with different resonant frequencies, each of the plurality of beam transducers having a beam and a proof mass suspended over a second opening in the substrate, and wherein the diaphragm and the beam of each of the plurality of beam transducers is formed from a polysilicon layer formed over the substrate. 
 
     
     
       18. The method of  claim 17  wherein forming comprises:
 etching the substrate to form a microphone cavity and a vibration sensor cavity; 
 depositing a first sacrificial layer within the microphone cavity and the vibration sensor cavity; 
 depositing the polysilicon layer over the first sacrificial layer; and 
 patterning the polysilicon layer to form the diaphragm of the MEMS microphone and the beam of each of the plurality of beam transducers. 
 
     
     
       19. The method of  claim 18  wherein the proof mass for each of the beam transducers is formed within the vibration sensor cavity during etching. 
     
     
       20. The method of  claim 18  wherein the polysilicon layer is a first polysilicon layer, and forming further comprises:
 depositing a second sacrificial layer over the diaphragm and the beam; 
 depositing a second polysilicon layer over the sacrificial layer; 
 patterning the second polysilicon layer to form a first top plate over the diaphragm and a second top plate over the beam; 
 etching a back side of the substrate to form the first opening and the second opening; and 
 using the first opening and the second opening, wet etching the first sacrificial layer and the second sacrificial layer to release the diaphragm, the beam and the proof mass.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the earlier filing date of U.S. Provisional Patent Application No. 62/261,750, filed Dec. 1, 2015 and incorporated herein by reference. 
    
    
     FIELD 
     Embodiments described herein relate to a micro-electro-mechanical systems (MEMS) microphone and vibration sensor die formed by MEMS processing steps. More specifically, an integrated MEMS microphone and vibration sensor die that can be used to eliminate unwanted sounds and improve vocal sound detection. 
     BACKGROUND 
     Contemporary electronics and portable electronic devices commonly include one or more microphones, and as more features are being introduced, more than one microphone may be included for complex audio processing. One such microphone is the electret condenser microphone (ECM) that includes a capacitive sensing plate and a field effect transistor (FET) amplifier. The FET amplifier can be in an integrated circuit (IC) die located within the microphone package enclosure. The IC die may additionally include an analog to digital converter (ADC) for digital microphone applications. 
     More recently, micro-electro-mechanical systems (MEMS) microphones have been introduced. Similar to an ECM, a MEMS microphone may feature capacitive sensing with a fixed diaphragm. In addition to an amplifier and ADC, a MEMS IC die may include a charge pump to bias to diaphragm. 
     ECM and MEMS microphone packages include a sound inlet, or hole, adjacent the capacitive sensing plate or membrane for operation, e.g., to allow the passage of sound waves that are external for the package. A particle filter may be provided in order to mitigate the impact of particles on operation. Sound waves entering through the sound inlet exert a pressure on the capacitive sensing plate or membrane, and an electrical signal representing the change a capacitance is generated. 
     Recently MEMS microphones have been adapted for use in mobile electronic devices such as smartphones, music players and mobile computers. In portable devices, however, the interference from unwanted environmental sounds (e.g., noise) becomes more problematic for audio sensing. Many of the technologies developed for eliminating or cancelling unwanted sounds use conventional microphones that detect sound through air. Such systems, however, may face challenges when it comes to distinguishing between desirable sounds falling within frequency ranges typical of unwanted sounds (e.g., low frequency ranges). 
     SUMMARY 
     Generally, the invention relates to a MEMS microphone and MEMS vibration sensor that are integrated as one, at the die or in some cases, the package, level. Representatively, in one embodiment, the MEMS microphone and MEMS vibration sensor are formed from a single die substrate using MEMS processing techniques. The MEMS microphone can be use to detect vocal sounds through the air while the MEMS vibration sensor can be used to detect vocal sounds based on contact with a vibrating surface of the user (e.g., portion of the neck near the user&#39;s vocal chords), in other words, mechanical vibrations. In this aspect, the MEMS vibration sensor may be used in conjunction with, or instead of, the MEMS microphone to maximize the vibration sensitivity and acoustic signal output of the device. Representatively, in one embodiment, the MEMS vibration sensor may be used to detect low frequency sounds using mechanical vibrations of the skin near the vocal cord of a user (e.g., the neck). The MEMS microphone may be designed to use air pressure changes in the air to detect vocal sounds that are outside of (e.g., higher), or overlapping with, the frequency range detectable by the vibration sensor. In this aspect, when vocal sound detection is desired yet a level of unwanted environmental sound is high (e.g., the user is in a subway, airport, traffic or at a rock concert), the MEMS vibration sensor instead of (or in addition to) the MEMS microphone may be used to detect the vocal sound using mechanical vibrations. The device therefore provides the advantage of being able to detect vocal sounds through vibration and/or air, and can be used to eliminate and/or minimize unwanted sounds in loud environments and improve vocal sound detection quality. 
     For example, in one aspect, the MEMS vibration sensor is mainly used to detect desired vocal sounds and eliminate undesirable environmental sounds. For example, the MEMS vibration sensor is used to detect vocal sound, not through air pressure change, but through mechanical vibration caused by the sound source, for example skin vibrations of the neck near the vocal cord. In addition, the MEMS microphone and vibration sensor die or package may include an application-specific integrated circuit (ASIC) die or system having electronic circuits with filters and equalizers to optimize sound signals and minimize unwanted environmental sounds by filtering, switching and/or amplifying signals from both the vibration sensor and microphone sensors selectively along desired audio frequency ranges. In one aspect, the microphone, the vibration sensor and the ASIC die may be integrated into a single package, as a single component. In another aspect, the microphone and vibration sensor are integrated in a single silicon die using MEMS processes. In another aspect, the microphone, the vibration sensor and signal conditioning components are integrated in a system board. The integrated microphone and vibration sensor die or package may be mounted in the controller part of an earpiece or headphone, by which a user can hold and move the device to touch or contact the skin of the neck to pick up the mechanical vibrations from the vocal cord. The controller may have a capacitive contact sensor (or mechanical button or motion sensor) switch on an inner side of the enclosure to detect the contact with the skin when the user holds and moves the device to the skin. The device can then send a signal indicating the user is using the controller for contact vibration sensing mode to the system, and the system can then turn on the vibration sensor and implement protocols for detecting sound through the vibration sensor and/or the microphone. 
     More specifically, in one embodiment, the MEMS microphone and vibration sensor die includes a die substrate, a MEMS microphone on the die substrate, and a MEMS vibration sensor on the die substrate. The MEMS vibration sensor may have a plurality of beam transducers and each of the plurality of beam transducers may have a beam and a proof mass. Each proof mass may be tuned to a different resonant frequency range and comprises a same material as the die substrate. In addition, in one embodiment, each beam may have a same length and/or each proof mass may have a different length dimension than another of the proof masses. In another aspect, the MEMS microphone may include a diaphragm made of a same material as the beams (e.g., a polysilicon material). In still further aspects, the MEMS vibration sensor may be operable to detect mechanical vibrations at a frequency range of from 20 Hz to 20 kHz, or different frequency ranges within that of human hearing, for example, a low frequency range (e.g., less than or equal to 100 Hz to 1 kHz), a middle frequency range (e.g., 1 kHz to 10) or a high frequency range (e.g., 10 kHz to 20 kHz). For example, in one embodiment, the proof mass of a first beam transducer is tuned to detect a mechanical vibration in a first frequency range and the proof mass of a second beam transducer is tuned to detect a mechanical vibration within a second frequency range that is different than the first frequency range. Representatively, the first beam transducer may detect a mechanical vibration in a low (e.g., less than or equal to 100 Hz to 1 kHz), middle (e.g., 1 kHz to 10 kHz) or high (e.g., 10 kHz to 20 kHz) frequency range, and the second beam transducer may detect a mechanical vibration outside of the range detected by the first beam transducer. In still further embodiments, the MEMS microphone and MEMS vibration sensor may detect vibrations within different frequency ranges. For example, the MEMS microphone may detect an acoustic vibrations within the mid to high frequency ranges (e.g., 1 kHz to 20 kHz) and the MEMS vibration sensor may detect mechanical vibrations within a low frequency range (e.g., 100 Hz to 1 kHz). In another aspect, the MEMS microphone and the MEMS vibration sensor are integrally formed with the die substrate as one integrally formed unit, and the integrally formed unit is mounted to a package substrate. The MEMS microphone and vibration sensor die may be incorporated into a remote control housing for a headphone. 
     In another embodiment, a headphone remote controller having multiple sensors is provided. The headphone remote controller may include a housing for a remote controller of a headphone, which includes a housing wall defining a vibration contact side for the remote controller. In addition, the controller may include a multiple sensor package positioned within the housing. The multiple sensor package may include a MEMS microphone, a plurality of MEMS beam transducers having different proof masses corresponding to different resonant frequencies, and an application-specific integrated circuit (ASIC) electrically connected to the MEMS microphone and the MEMS beam transducers. In addition, the controller may include a printed circuit board (PCB) positioned within the housing to which the multiple sensor package is mounted to the PCB. In addition, a capacitive contact sensor may be mounted to the wall defining the vibration contact side for the remote controller. In one aspect, the multiple sensor package is mounted to a side of the PCB facing the vibration contact side for the remote controller. In addition, the different proof masses may be connected to a plurality of beams, and each of the beams have a same length dimension. Still further, the MEMS microphone and the plurality of beam transducers may be integrally formed with a die substrate as a single integrally formed unit, and the single integrally formed unit is mounted to a package substrate. The MEMS microphone may be connected to a first die substrate and the plurality of beam transducers may be connected to a second die substrate, and the first die substrate and the second die substrate may be separately mounted to the package substrate. In one embodiment, the MEMS microphone is operable to sense air pressure changes corresponding to a first frequency range and the plurality of beam transducers are operable to sense mechanical vibrations corresponding to a second frequency range. In addition, the capacitive contact sensor may include a pattern of contacts operable to detect a contact between the housing and a user. For example, a width of the contact with respect to the pattern of contacts is used to differentiate between a first contact indicating a user is using the remote controller to control the headphone and a second contact indicating the user is sensing a vocal cord vibration through the user&#39;s skin. 
     In still further embodiments, a process for manufacturing a MEMS microphone and vibration sensor die is disclosed. Representatively, the process may include providing a substrate and forming a MEMS microphone and a MEMS vibration sensor from the substrate. The MEMS microphone may include a diaphragm and a top plate suspended over a first opening in the substrate. The MEMS vibration sensor may include a plurality of beam transducers with different resonant frequencies, each of the plurality of beam transducers having a beam and a proof mass suspended over a second opening in the substrate. In one embodiment, the diaphragm and the beam of each of the plurality of beam transducers is formed from a polysilicon layer formed over the substrate. In one embodiment, forming the MEMS microphone and MEMS vibration sensor may include etching the substrate to form a microphone cavity and a vibration sensor cavity, depositing a first sacrificial layer within the microphone cavity and the vibration sensor cavity, depositing the polysilicon layer over the first sacrificial layer; and patterning the polysilicon layer to form the diaphragm of the MEMS microphone and the beam of each of the plurality of beam transducers. The proof mass for each of the beam transducers may be formed within the vibration sensor cavity during etching. In one embodiment, the polysilicon layer is a first polysilicon layer, and forming further includes depositing a second sacrificial layer over the diaphragm and the beam, depositing a second polysilicon layer over the sacrificial layer, patterning the second polysilicon layer to form a first top plate over the diaphragm and a second top plate over the beam, etching a back side of the substrate to form the first opening and the second opening, and using the first opening and the second opening, wet etching the first sacrificial layer and the second sacrificial layer to release the diaphragm, the beam and the proof mass. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and they mean at least one. 
         FIG. 1  is a cross-sectional side view illustration of a MEMS microphone and vibration sensor die in accordance with an embodiment. 
         FIG. 2  is a schematic top view illustration of the MEMS microphone and vibration sensor die of  FIG. 1 . 
         FIGS. 3-14  illustrate a process for manufacturing a MEMS microphone and vibration sensor die in accordance with an embodiment. 
         FIG. 15  is a cross-sectional side view illustration of a MEMS microphone and vibration sensor package in accordance with an embodiment. 
         FIG. 16  is a cross-sectional side view illustration of a MEMS microphone and vibration sensor package in accordance with another embodiment. 
         FIG. 17  is a cross-sectional side view illustration of remote controller for a headphone including a MEMS microphone and vibration sensor package in accordance with an embodiment. 
         FIG. 18  is a schematic top view of a contact sensor incorporated into the remote controller of  FIG. 17 . 
         FIG. 19  is a schematic illustration of one application of the remote controller of  FIG. 17  by a user in accordance with an embodiment. 
         FIG. 20  is a schematic illustration of another application of the remote controller of  FIG. 17  by a user in accordance with an embodiment. 
         FIG. 21  is a process flow for reducing unwanted environmental sound and optimizing desired sound signal using a MEMS microphone and vibration sensor die in accordance with an embodiment. 
         FIG. 22  illustrates a simplified schematic view of one embodiment of an electronic device in which a MEMS microphone and vibration sensor die and/or package as disclosed herein may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     In various embodiments, description is made with reference to figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions and processes, etc., in order to provide a thorough understanding of the embodiments. In other instances, well-known semiconductor processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the embodiments. Reference throughout this specification to “one embodiment” means that a particular feature, structure, configuration, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment” in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. The terms “over”, “to”, and “on” as used herein may refer to a relative position of one feature with respect to other features. One feature “over” or “on” another feature or bonded “to” another feature may be directly in contact with the other feature or may have one or more intervening layers. 
       FIG. 1  is a cross-sectional side view illustration of a MEMS microphone and vibration sensor die in accordance with an embodiment. As shown, the MEMS microphone and vibration sensor die  100  may include a MEMS microphone  102  and a MEMS vibration sensor  104  formed within a single die substrate  106 . In other words, the MEMS microphone  102  and MEMS vibration sensor  104  may be integrally formed using MEMS processing technology as a single unit, such that they are not separable from one another or the die substrate  106 . 
     The MEMS microphone  102  may include a diaphragm  108  and a top plate  110  positioned over, or above, a sound inlet opening  120  formed in the die substrate  106 . MEMS microphone  102  may further include an anchor layer  116  between the diaphragm  108  and die substrate  106 . In addition, an attachment layer  114  may be formed between the diaphragm  108  and the top plate  110 . The attachment layer  114  spaces the diaphragm  108  apart from the top plate  110  so that an air gap  118  for capacitance measurement is formed between the diaphragm  108  (which may function as a movable bottom electrode) and the top plate  110  (which may function as a fixed top electrode). The top plate  110  may further include perforations  112  to allow for air to flow through the top plate  110 . During operation, sound waves travel through the sound inlet opening  120  causing the diaphragm  108  (which is a relatively thin solid structure) to move or vibrate in response to the change in air pressure caused by the sound waves. The movement of diaphragm  108  creates a change in the amount of capacitance between the top plate  110  (which is a relatively stiff structure) and the diaphragm  108 , which is then translated into an electrical signal by, for example, an application-specific integrated circuit (ASIC) (not shown). 
     MEMS vibration sensor  104  may be a multi resonance frequency beam (MRFB) vibration sensor with multiple beam transducers having different proof masses that can be used to improve vibration sensitivity of the device in wide frequency ranges and/or low frequency ranges. For example, the MEMS vibration sensor  104  may be used to detect mechanical vibrations within a same, or different, frequency range as the MEMS microphone  102 , for example, a frequency range of from about 20 Hz to about 20 kHz. In this aspect, the MEMS vibration sensor  104  can be used to maximize a vibration sensitivity of the MEMS microphone within a range of human hearing. Representatively, in some cases, vocal sounds and unwanted environmental sounds are within the same frequency ranges, for example, low frequency ranges. Therefore, when the MEMS microphone  102  detects sounds within these ranges through air, some may be wanted (e.g., vocal sounds) while others are unwanted (e.g., traffic sounds), yet the MEMS microphone  102  picks up both. The MEMS vibration sensor  104 , however, is configured to detect vocal sounds through mechanical vibrations of a vibrating surface of the user (e.g., skin near the vocal cords). Thus, in a noisy environment where the level of unwanted sounds is high, the MEMS microphone  102  may be inactivated, and the MEMS vibration sensor  104  is instead used to detect only the vocal sounds through the vibration of the skin around the users vocal cords. In this aspect, the other unwanted environmental sounds (e.g., traffic, rock concert noise, subway, etc.), which the MEMS microphone  102  would normally pick up through the air, are eliminated. 
     In this aspect, the MEMS microphone  102  and MEMS vibration sensor  104  may detect sounds within a same frequency range (e.g., 20 Hz to 20 kHz), while in other embodiments, the MEMS microphone  102  and the MEMS vibration sensor  104  may detect sounds within different and/or overlapping frequency ranges. For example, the MEMS vibration sensor  104  may detect low frequency mechanical vibrations (e.g., less than or equal to 100 Hz to 1 kHz) and the MEMS microphone  102  may detect acoustic vibrations in the middle frequency range (e.g., 1 kHz to 10 kHz) and/or high frequency range (e.g., 10 kHz to 20 kHz). 
     In addition, the MEMS vibration sensor  104  may include one or more beam transducers  132  having beams  122 ,  128  (see  FIG. 2 ) and proof masses  124 ,  126  which are tuned to have different resonant frequencies such that the beam transducers  132  can detect mechanical vibrations within different frequency ranges. It should be understood that a “mechanical vibration” is intended to refer to a vibrating surface or structure, the vibrations of which can be detected by contacting the MEMS vibration sensor  104  with the vibrating surface, as opposed to vibrations that are detected through air by the MEMS microphone  102 , and referred to herein as acoustic vibrations. 
     In one embodiment, the dimensions of beams  122 ,  128  may be the same while the dimensions (or mass) of proof masses  124 ,  126  may be different (or tuned) so that the transducers have different resonant frequencies which correspond to a desired frequency range. For example, proof mass  124  may have a smaller area or mass than proof mass  126 . In this aspect, the transducer having proof mass  124  has a higher resonant frequency than the transducer having proof mass  126 . For example, in one embodiment, both proof masses  124  and  126  may be used to detect low frequency vibrations, however, proof mass  126  may be tuned to detect frequencies within the low end of the low frequency range (e.g., 100 Hz to 500 Hz) and proof mass  124  may be tuned to detect frequencies within the high end of the low frequency range (e.g., 500 Hz to 1 kHz). Alternatively, proof mass  126  may be tuned so that the beam transducer detects mechanical vibrations with the low frequency range (e.g., 100 Hz to 1 kHz), the middle frequency range (e.g., 1 kHz to 10 kHz) and/or the high frequency range (e.g., 10 kHz to 20 kHz) and proof mass  124  may be tuned so that the other beam transducer detects mechanical vibrations outside the range of the transducer with proof mass  126 . 
     The beams  122 ,  128  may be positioned over (or above) an opening  140  within die substrate  106 . Similar to the MEMS microphone  102 , MEMS vibration sensor  104  may further include anchor layer  116  between the beams  122 ,  128  and die substrate  106  and attachment layer  114  between the beams  122 ,  128  and a top plate  130 . In this aspect, it should be recognized that because both the MEMS microphone  102  and MEMS vibration sensor  104  are formed using MEMS processing steps, they have components formed from a same material layer (e.g., diaphragm  108  and beams  122 ,  128 ) and/or share at least one common material layer (e.g., the anchor layer  116  or the attachment layer  114 ). In addition, an air gap  134  for capacitance measurement is formed between the beams  122 ,  128  (which may function as a movable bottom electrode) and the top plate  130  (which may function as a fixed top electrode). The change in capacitance due to the movement of the beams  122 ,  128  is then translated into an electrical signal by the same ASIC (not shown) used for the MEMS microphone  102 . 
       FIG. 2  is a schematic top view illustration of the MEMS microphone and vibration sensor die of  FIG. 1 . From this view, the dimensions of beams  122 ,  128  and proof masses  124 ,  126  can be seen. In particular, the dimensions of beam  122  and beam  128  may be substantially the same. Representatively, length (L 122 ) of beam  122  may be substantially the same as length (L 128 ) of beam  128 . The dimensions or masses of proof mass  124  and proof mass  126  may be different. Representatively, length (L 124 ) of proof mass  124  may be shorter than the length (L 126 ) of proof mass  126 . It should further be understood that while different lengths are used to illustrate the different dimensions or masses of proof masses  124 ,  126 , it is contemplated that a width, thickness, or other aspect of the proof mass dimension may be changed in order to achieve a multi frequency vibration sensor. 
       FIGS. 3-14  illustrate a process for manufacturing a MEMS microphone and vibration sensor die in accordance with an embodiment. Representatively, according to  FIG. 3 , process  300  includes the initial processing operation of providing a substrate  302 . Substrate  302  may, for example, be a silicon or Silicon-on-Insulator (SOI) substrate wafer from which the MEMS microphone and MEMS vibration sensor can be formed to produce a multi frequency MEMS microphone and vibration sensor die. 
       FIG. 4  illustrates the further processing operation of forming a microphone cavity  402  and a vibration sensor cavity  404  within a top side  410  of substrate  302 . Representatively, microphone cavity  402  and vibration sensor cavity  404  may be formed using a deep reactive ion etching (DRIE) process. The vibration sensor cavity  404  may be formed to include two separate masses  406  and  408  (e.g., proof masses  124 ,  126 ) formed from the substrate  302  (e.g., they include a same material), such as by further masking and etching steps. The different masses  406  and  408  will serve as the proof masses (e.g., proof masses  124 ,  126 ) for the multi frequency beam transducers of the vibration sensor. In this aspect, the masses  406  and  408  will be formed to have a desired size and/or mass so that the corresponding transducers have the desired resonant frequencies (e.g., different resonant frequencies). 
       FIG. 5  illustrates the further processing operation of depositing sacrificial layer  502  over the top side  410  of substrate  302  and within microphone cavity  402  and vibration sensor cavity  404 . In particular, the sacrificial layer  502  may be a layer of material applied over the substrate  302 , microphone cavity  402  and vibration sensor cavity  404 , such that it fills the cavities and surrounds the masses  406  and  408  within vibration sensor cavity  404 . Once the cavities are filled, the layer is planarized, such as by chemical mechanical planarization (CMP), to remove portions of the layer on the top side  410  of substrate  302  and masses  406  and  408 . The sacrificial layer  502  may, for example, be made of silicon dioxide (SiO 2 ). 
       FIG. 6  illustrates the further processing operation of applying an anchor layer  602  over sacrificial layer  502 . Representatively, anchor layer  602  may be formed by applying a layer of a suitable material over sacrificial layer  502  and then planarizing the layer (e.g., CMP) to form a smooth layer having a consistent thickness. Similar to the sacrificial layer  502 , the anchor layer  602  may, for example, be made of silicon dioxide (SiO 2 ). 
       FIG. 7  illustrates the further processing operation of applying a polysilicon layer  702  over the anchor layer  602 . The polysilicon layer  702  may then be planarized (e.g., CMP) to form a smooth layer that can then be used to form the diaphragm for the MEMS microphone and beam structures for the MEMS vibration sensor. In this aspect, the diaphragm for the MEMS microphone and the beams for the MEMS vibration sensor may be formed from the same material layer, in other words, formed of a same polysilicon material. 
     In particular,  FIG. 8  illustrates the further processing operation of forming a diaphragm  802  (e.g., diaphragm  108  of  FIGS. 1-2 ) and one or more of a beam  804  (e.g., beams  122 ,  128  of  FIG. 2 ) from polysilicon layer  702 . Representatively, a mask (e.g., patterned photoresist) may be applied over polysilicon layer  702 . Portions of the polysilicon layer  702  that are exposed by the mask may then be etched to remove them, leaving behind the diaphragm  802  and one or more of the beam  804  structures. It is noted that from this view, only a single beam  804  can be seen, however, at least two beams as shown, for example, in  FIG. 2 , are formed over proof mass  406  and proof mass  408 . 
       FIG. 9  illustrates the further processing operation of forming another sacrificial layer  902  over anchor layer  602 , diaphragm  802  and one or more of the beam  804 . Similar to sacrificial layer  502 , sacrificial layer  902  may be formed by applying a layer of silicon dioxide (SiO 2 ) over anchor layer  602 , diaphragm  802  and one or more of beam  804 . The layer of silicon dioxide (SiO 2 ) is then planarized as previously discussed to form sacrificial layer  902 . 
       FIG. 10  illustrates the further processing operation of forming another polysilicon layer  1002 . Polysilicon layer  1002  is formed by applying a layer of polysilicon over sacrificial layer  902 . Polysilicon layer  1002  may be used to form the top plates for each of the MEMS microphone and vibration sensor. Therefore, in one embodiment, the layer of polysilicon used to form polysilicon layer  1002  may be thicker than the layer of polysilicon used to form diaphragm  802  and the beam  804  so that the resulting top plates are relatively stiff, rigid structures in comparison to the diaphragm  802  and beam  804 . 
       FIG. 11  illustrates the further processing operation of forming a top plate  1102  for the MEMS microphone and top plate  1104  for the MEMS vibration sensor from polysilicon layer  1002 . Representatively, a mask (e.g., patterned photoresist) may be applied over polysilicon layer  1002 . Portions of the polysilicon layer  1002  that are exposed by the mask may then be etched to remove them, leaving behind top plates  1102  and  1104 . 
       FIG. 12  illustrates the further processing operation of forming perforated openings  1202 , in top plate  1102  and top plate  1104  to reduce damping. Representatively, top plate  1102  and top plate  1104  may be patterned to form perforated openings  1202 , which extend through the entire thickness of the plates, as shown in  FIG. 12 . 
       FIG. 13  illustrates the further processing operation of forming openings  1302  and  1304  within a back or bottom side  1306  of substrate  302 . Representatively, in one embodiment, a DRIE etching process is performed on the bottom side  1306  of substrate  302  to remove the silicon beneath the sacrificial layer  502  and proof masses  406 ,  408  and expose the sacrificial layers  502  and  902 . 
       FIG. 14  illustrates the further processing operation of removing portions of the sacrificial layers  502  and  902  and anchor layer  602 . Representatively, wet etching is performed, for example through openings  1302  and  1304  or perforated openings  1202 , in order to remove a portion of sacrificial layer  902  above diaphragm  802  leaving air gap  1402 . In addition, wet etching may be used to remove a portion of sacrificial layer  902  and anchor layer  602  below diaphragm  802 . The edges of diaphragm  802 , however, remain sandwiched between portions of sacrificial layer  902  and anchor layer  602  surrounding the air gap  1402  and opening  1302  such that diaphragm  802  is suspended over opening  1302  and free to vibrate. Similarly, the wet etching step removes a portion of sacrificial layer  902  above one or more of beam  804  leaving air gap  1404  and a portion of sacrificial layer  902  and anchor layer  602  below beam  804  and surrounding proof masses  406 ,  408 . An anchor layer portion  1406  of anchor layer  602  between one or more of beam  804  and the respective proof masses  406 ,  408 , however, remains such that the anchor layer portion  1406  serves to attach the proof masses  406 ,  408  to their respective beam  804 . In addition, the ends of one or more of beam  804  remain sandwiched between portions of sacrificial layer  902  and anchor layer  602  surrounding the air gap  1404  and opening  1304  such that each beam  804  is suspended over opening  1304 . In other words, both of the opposing ends (in the length direction) of beam  804  are attached to, fixed to, or otherwise secured to, substrate  302 . The resulting structure is a single, integrally formed die including a MEMS microphone  102  and MEMS vibration sensor  104  as previously discussed in reference to  FIGS. 1-2 . 
     It should be understood that although various processing operations are described in  FIGS. 3-14 , any one or more of these operations may be performed in a different order and/or omitted and/or additional steps may be performed according to manufacturing protocols. Representatively, although a single, integrally formed MEMS microphone and vibration sensor die with inseparable components is disclosed in  FIG. 14 , in another embodiment, a further sawing step may be used to separate the MEMS microphone  102  from the vibration sensor  104 . 
     The integrated MEMS microphone and vibration sensor die formed using the processing operations described in  FIGS. 3-14  may then be integrated within a package assembly for incorporation into a desired device (e.g., a remote controller for a headphone). 
       FIG. 15  is a cross-sectional side view illustration of a MEMS microphone and vibration sensor package in accordance with an embodiment. MEMS microphone and vibration sensor package  1500  may include a multi frequency MEMS microphone and vibration sensor die  100 , such as that described in reference to  FIGS. 1-2 . In particular, MEMS microphone and vibration sensor die  100  may include a MEMS microphone  102  and MEMS vibration sensor  104  integrally formed from die substrate  106  using the processing operations described in  FIGS. 3-14 . The MEMS microphone and vibration sensor die  100  may be positioned on, and attached to, package substrate  1502 . Representatively, the MEMS microphone and vibration sensor die  100  may be stacked on top of package substrate  1502  and a layer of die attach material  1506  positioned between die  100  and package substrate  1502  to mechanically attach the two together. Package substrate  1502  may include a sound inlet port  1512 , which aligns with opening  120  through the die substrate  106  to allow for sound inlet to MEMS microphone  102 . 
     The MEMS microphone and vibration sensor package  1500  may further include an IC die  1504 , such as an application specific integrated circuit (ASIC) die, positioned on, and attached to, package substrate  1502 . Representatively, the layer of die attach material  1506  may be used to attach IC die  1504  to package substrate  1502 . In addition, IC die  1504  may be electrically connected to MEMS microphone and vibration sensor die  100  and package substrate  1502  with wire bonds  1508 , one between die  100  and IC die  1504  and another between IC die  1504  and package substrate  1502 . A package lid  1510  may further be attached to the package substrate  1502  and over the MEMS microphone and vibration sensor die  100  and IC die  1504 , to complete the package assembly. Package substrate  1502  may be any suitable substrate, such as land grid array (LGA), quad flat no-leads (QFN), and ceramic packaging substrates. 
     It should be understood that embodiments are not limited to the specific packaging structure illustrated in  FIG. 15 , and it is meant to be exemplary in nature. For example, the MEMS microphone and vibration sensor die  100  and IC die  1504  may be stacked on the package substrate  1502  and the wire bonding arrangement included as necessary. Alternatively, bumps (for example, through flip chip) or other techniques for electrically connecting one component to another may be used. 
     In addition, the IC die  1504  may include a variety of components including an amplifier, ADC, charge pump, clock(s) (or clock inputs) and other signal conditioning components such as spectral mixers. The particular components can vary based on application, and whether the MEMS microphone and/or MEMS vibration sensor are analog or digital. It should be noted that since the MEMS microphone and MEMS vibration sensor are both electrically connected to the IC die  1504 , they use the same circuitry and signal conditioning components, which is a further advantage of the integrated MEMS microphone and vibrations sensor die  100 . In other configurations, one or more components from the IC die  1504  can be integrated into the MEMS microphone and vibration sensor die  100 , and/or other component arrangements used. 
       FIG. 16  is a cross-sectional side view illustration of a MEMS microphone and vibration sensor package in accordance with another embodiment. The MEMS microphone and vibration sensor package  1600  includes substantially the same components as the MEMS microphone and vibration sensor package  1500  described in reference to  FIG. 15 , except in this embodiment, MEMS microphone  102  and MEMS vibration sensor  104  are separate structures having separate die substrates  106 A,  106 B, respectively. In this aspect, MEMS microphone  102 , including substrate  106 A, and MEMS vibration sensor  104 , including die substrate  106 B, are separately attached to package substrate  1502  with die attach material layer  1506 . In addition, because MEMS microphone  102  and MEMS vibration sensor  104  are separate structures, an additional wire bond  1508  is used to electrically connect MEMS microphone  102  to MEMS vibration sensor  104 . 
       FIG. 17  is a cross-sectional side view illustration of remote controller for a headphone including a MEMS microphone and vibration sensor package in accordance with an embodiment. Representatively,  FIG. 17  shows a remote controller  1700  including a MEMS microphone and vibration sensor package  1500  (as described in reference to  FIG. 15 ). The remote controller  1700  may be a remote controller used to operate a headphone connected to the controller and therefore, although not shown, may include various components for such an operation. In addition, the remote controller  1700  may be used to sense vocal sounds using the MEMS microphone and vibration sensor package  1500  incorporated therein. It should be further understood that although package  1500  is illustrated, the remote controller  1700  may instead include the MEMS microphone and vibration sensor package  1600  described in reference to  FIG. 16 , or any other combination of MEMS microphone and vibration sensor components described herein. 
     Representatively, MEMS microphone and vibration sensor package  1500  may be positioned within remote controller housing  1702 . Housing  1702  may include an enclosure wall  1704  having a top wall  1706 , a bottom wall  1708  and sidewalls  1720 ,  1722 . Sidewalls  1720 ,  1722  connect the top wall  1706  to the bottom wall  1708  such that the housing  1702  completely encloses each of the components therein. The top wall  1706  may be considered a contact side for the remote controller in that it is the side the user contacts to the vibration portion of the body (e.g., the skin on the neck) to detect the vocal vibrations. The bottom wall  1708  may include an optional opening  1726  that allows for sound from the environment to travel into the housing  1702 , for pick up by the microphone. It should be understood, however, that in some embodiments, opening  1726  may be formed in a different wall, or omitted and instead an air gap formed between the top wall  1706  and bottom wall  1708  allows for sound inlet to housing  1702 . The housing  1702 , and various components therein, may be connected to the headphones (not shown) by cord  1712 , within which the various wires may be contained. 
     Representatively, the wires within cord  1712  may be electrically connected to a printed circuit board (PCB)  1710  positioned within housing  1702 . The MEMS microphone and vibration sensor  1500  may be mechanically and electrically connected to PCB  1710 , for example, by solder bumps or the like. The MEMS microphone and vibration sensor package  1500  may be connected to a side of PCB  1710  facing the vibration contact side of the housing  1702 , for example, the side facing top wall  1706 . During operation, when it is desired to detect the user&#39;s vocal sounds using the mechanical vibrations of the vocal cords (e.g., in a loud environment), the top wall  1706  of housing  1702  is pressed against the user&#39;s neck (near the vocal cords) and the vocal cord vibrations are transmitted through the contact side of housing  1702  to the MEMS microphone and vibration sensor package  1500 . For example, the vibrations travel through top wall  1706 , side wall  1722 , the PCB  1710  and are then picked up by the vibration sensor within MEMS microphone and vibration sensor  1500  attached to PCB  1710 . The PCB  1710  may further include a sound inlet port  1724  that is aligned with the sound inlet opening of the MEMS microphone (e.g., sound inlet opening  1512  as described in reference to  FIG. 15 ). Sound inlet port  1724  of PCB  1710  allows sound waves passing through the optional opening  1726  within the enclosure wall  1704  of housing to travel to, and be picked up by, the microphone. 
     Remote controller  1700  may further include a capacitive contact sensor  1718  positioned along an inner surface of housing wall  1704 . The capacitive contact sensor  1718  may be used to differentiate between contact with a user&#39;s finger, for example, for normal remote control operations (e.g., for controlling the headphone) and contact with the skin on the neck to detect vocal cord vibrations. In particular, the contact sensor  1718  may be positioned along an inner surface of the contact side or top wall  1706  of housing  1702 . When the user presses the contact side or top wall  1706  of housing  1706  against the neck to detect vocal cord vibrations (e.g., mechanical vibrations), the contact sensor  1718  signals to the MEMS microphone and vibration sensor package  1500  that vocal cord vibration sensing is desired and therefore sound should be detected using the vibration sensor within package  1500 , instead of, or in addition to the MEMS microphone. Alternatively, when contact sensor  1718  senses that the user is touching the contact side or top wall  1706  with their finger, such as to control headphone operations, the contact sensor  1718  does not send a signal to use the vibration sensor for vocal sound pick-up and the MEMS microphone continues to pick up vocal sounds through the air. It should further be understood that while a capacitive contact sensor is shown, other types of contact sensors may be used to switch the MEMS microphone and vibration sensor between normal and vibration sensing modes. For example, a contact sensor such as a motion (e.g., accelerometer) or mechanical sensor may be mounted within remote controller  1700 . 
       FIG. 18  is a schematic top view of the contact sensor of  FIG. 17 . From this view, it can be seen that contact sensor  1718  includes a support member  1802  with a number of contact sensing regions  1804 A,  1804 B,  1804 C,  1804 D and  1804 E positioned in a desired sensing pattern, and connected by a contact strip  1806  (e.g., a silver or copper tape). The sensing pattern may be such that the contact sensing regions  1804 A- 1804 E are distributed across a length of the support member  1802 . In this aspect, the difference between contact by a finger, such as to control the headphones, and contact with the skin on a user&#39;s neck, such as to initiate vibration sensing, can be distinguished based on the coverage area of the contact. In other words, if a touch is sensed at only one contact region, e.g., contact sensing region  1804 C, the contact sensor  1718  characterizes this as contact by a finger for a headphone operation. In contrast, if a touch is sensed over a wider area, for example at least two or more of contact sensing regions  1804 A- 1804 E, e.g., contact sensing regions  1804 A,  1804 B,  1804 C and  1804 D, the contact sensor  1718  characterizes this as a contact with the skin on a user&#39;s neck and vibration sensing is initiated. Although not shown, the contact sensor  1718  may further include a wire electrically connecting the contact sensor  1718  to a controller within PCB  1710 . 
     Returning to  FIG. 17 , controller  1700  may further include passive components  1716 , or other IC components, and one or more mechanical switches  1714  connected to PCB  1710  for controlling headphone operations (e.g., volume adjustment, on/off modes, etc.). 
       FIGS. 19-20  are schematic illustrations of the application of the remote controller of  FIG. 17  by a user in a normal (headphone control) mode and a vibration detection mode. Representatively,  FIG. 19  shows the remote controller  1700  in the normal mode and  FIG. 20  shows the remote controller  1700  in a vibration mode. In particular, in  FIG. 19 , in the normal mode  1900 , a user is shown with the headphones  1902  (e.g., earbuds) positioned in each ear and remote controller  1700  hanging from headphones  1902  by cord  1712 . This is considered a “normal mode” in that the remote controller  1700  is being used to control the headphone operations, or for normal microphone operations (e.g., to pick up vocal sounds through the air). In contrast,  FIG. 20  shows the vibration mode  2000 , in which the user is touching the contact side of the remote controller to the neck skin near the user&#39;s vocal cords. Due to the wide contact area caused by the skin on the users neck, the contact sensor within the remote controller  1700  senses this as a vibration sensing contact and signals to the MEMS microphone and MEMS vibration sensor within the remote controller  1700  to pick-up the mechanical vibrations using the vibration sensor. 
       FIG. 21  is a process flow for reducing unwanted environmental sound and optimizing desired sound signals using a MEMS microphone and vibration sensor die in accordance with an embodiment. Representatively, according to one process for reducing unwanted environmental sound and optimizing desired sound, the process  2100  includes holding a remote controller including a MEMS microphone and vibrations sensor die package (e.g., remote controller  1700 ) and moving the remote controller so that it touches a vibration surface (e.g., neck) of the user&#39;s body (block  2102 ). Based on the movement, the contact sensor within the remote controller senses that mechanical vibration sensing of the vocal cord vibrations through the user&#39;s skin with the vibration sensor is desired by the user (as opposed to through the air), and sends a signal to the vibration sensor to switch to vibration sensing mode and detect vocal sounds through mechanical vibrations (e.g., vibration of the skin around the vocal cords) (block  2104 ). The contact sensor may, for example, be a capacitive contact sensor as previously discussed, or a motion (e.g., accelerometer) or mechanical sensor mounted to the remote controller, or integrated within the MEMS microphone and vibration sensor package. Once in vibration mode, filters on the ASIC die associated with the MEMS microphone and vibration sensor die may attenuate signals within frequency ranges where typical unwanted sounds occur and that are typically detected by the MEMS microphone (block  2106 ). Alternatively, MEMS microphone may be inactivated or turned to stand by mode, so that unwanted sound pick up through air by the MEMS microphone is completely eliminated. In addition, equalizers on the ASIC die may be used to optimize or otherwise make mechanical vibration signals (e.g., vocal cord vibrations) detected by the vibration sensor similar to vocal signals (block  2108 ). Once processed, the signals may be output to an end user (block  2110 ). 
       FIG. 22  illustrates a simplified schematic view of one embodiment of an electronic device in which a MEMS microphone and vibration sensor die and/or package as disclosed herein may be implemented. For example, a remote controller for a headphone, such as an inter-canal earphone or an intra-concha earphone, as discussed in reference to  FIGS. 17-20  are examples of systems that can include some or all of the circuitry illustrated by electronic device  2200 . 
     Electronic device  2200  can include, for example, power supply  2202 , storage  2204 , signal processor  2206 , memory  2208 , processor  2210 , communication circuitry  2212 , and input/output circuitry  2214 . In some embodiments, electronic device  2200  can include more than one of each component of circuitry, but for the sake of simplicity, only one of each is shown in  FIG. 22 . In addition, one skilled in the art would appreciate that the functionality of certain components can be combined or omitted and that additional or less components, which are not shown in  FIG. 22 , can be included in, for example, the remote controller device  1700  described in  FIG. 17 . 
     Power supply  2202  can provide power to the components of electronic device  2200 . In some embodiments, power supply  2202  can be coupled to a power grid such as, for example, a wall outlet. In some embodiments, power supply  2202  can include one or more batteries for providing power to earphones, headphones or other type of electronic device associated with the headphone. As another example, power supply  2202  can be configured to generate power from a natural source (e.g., solar power using solar cells). 
     Storage  2204  can include, for example, a hard-drive, flash memory, cache, ROM, and/or RAM. Additionally, storage  2204  can be local to and/or remote from electronic device  2200 . For example, storage  2204  can include an integrated storage medium, removable storage medium, storage space on a remote server, wireless storage medium, or any combination thereof. Furthermore, storage  2204  can store data such as, for example, system data, user profile data, and any other relevant data. 
     Signal processor  2206  can be, for example a digital signal processor, used for real-time processing of digital signals that are converted from analog signals by, for example, input/output circuitry  2214 . After processing of the digital signals has been completed, the digital signals could then be converted back into analog signals. 
     Memory  2208  can include any form of temporary memory such as RAM, buffers, and/or cache. Memory  2208  can also be used for storing data used to operate electronic device applications (e.g., operation system instructions). 
     In addition to signal processor  2206 , electronic device  2200  can additionally contain general processor  2210 . Processor  2210  can be capable of interpreting system instructions and processing data. For example, processor  2210  can be capable of executing instructions or programs such as system applications, firmware applications, and/or any other application. Additionally, processor  2210  has the capability to execute instructions in order to communicate with any or all of the components of electronic device  2200 . 
     Communication circuitry  2212  may be any suitable communications circuitry operative to initiate a communications request, connect to a communications network, and/or to transmit communications data to one or more servers or devices within the communications network. For example, communications circuitry  2212  may support one or more of Wi-Fi (e.g., a 802.11 protocol), Bluetooth®, high frequency systems, infrared, GSM, GSM plus EDGE, CDMA, or any other communication protocol and/or any combination thereof. 
     Input/output circuitry  2214  can convert (and encode/decode, if necessary) analog signals and other signals (e.g., physical contact inputs, physical movements, analog audio signals, etc.) into digital data. Input/output circuitry  2214  can also convert digital data into any other type of signal. The digital data can be provided to and received from processor  2210 , storage  2204 , memory  2208 , signal processor  2206 , or any other component of electronic device  2200 . Input/output circuitry  2214  can be used to interface with any suitable input or output devices, such as, for example, a further microphone. Furthermore, electronic device  2200  can include specialized input circuitry associated with input devices such as, for example, one or more proximity sensors, accelerometers, etc. Electronic device  2200  can also include specialized output circuitry associated with output devices such as, for example, one or more speakers, earphones, etc. 
     Lastly, bus  2216  can provide a data transfer path for transferring data to, from, or between processor  2210 , storage  2204 , memory  2208 , communications circuitry  2212 , and any other component included in electronic device  2200 . Although bus  2216  is illustrated as a single component in  FIG. 22 , one skilled in the art would appreciate that electronic device  2200  may include one or more bus components. 
     It should further be understood that although not specifically disclosed, in accordance with embodiments, other types of vibration sensing transducers may be used that operate in accordance with various transduction principles, such as capacitive, piezoelectric, and piezoresistive. The sensing transducers may, for example, include multiple transducer components per each axis (e.g., X, Y and Z) on a single transducer die, with the multiple transducer components having various resonant frequency ranges. For example, the sensing transducers may include a plurality of cantilever beams with different lengths arranged in one or more rows, each of the transducers corresponding to different resonant frequency ranges. It is further contemplated that the sensing transducers may include multiple transducers in a single axis (e.g., X, Y, or Z), and/or may have different resonant frequency ranges to sense in a range of frequencies. Various resonant frequency ranges may be achieved by changing spring and/or proof mass structures of the sensing transducers as disclosed herein. Thus, multiple X, Y, Z axis transducers can be formed on a single die having various resonant frequency ranges by changing proof mass dimensions and/or beam spring structures for frequency modulation and equalization. Additionally, multiple transducers can be located on the die surface in alternating manners in order to maximize die area. Furthermore, sensing transducers can be duplicated with the same design and dimension in the same axis in order to increase a signal to noise ratio (SNR). In an embodiment, vibration sensing transducers operating in accordance with piezoelectric transduction principles may provide power savings since piezoelectric sensing transducers can be power generators and not require a bias voltage. 
     In addition, although not specifically disclosed, in accordance with embodiments, a motion sensor may be integrally formed within the MEMS microphone and vibration sensor die. Representatively, the motion sensor may be a Y axis motion sensor formed within and/or on the same substrate as the MEMS microphone and MEMS vibration sensor using the same MEMS processing steps. For example, the motion sensor may include a proof mass, folded springs and sensing comb structures that can be used to detect a motion of the MEMS microphone and vibration sensor die within which it is integrated. In particular, the motion sensor can detect the motion of a user moving the MEMS microphone and vibration sensor die to the neck to detect a vibration of the vocal cords, and this information can then be used to initiate a mechanical vibration detection mode where the vibration sensor is used to detect sound instead of, or in addition to, the MEMS microphone. 
     In one aspect, the MEMS microphone and vibration sensor packages in accordance with embodiments incorporating multiple sensing transducers may cover a wider frequency range, with a more consistent sensitivity, compared to a traditional microphone such as ECM. Since the vibration sensors may be formed in a batch process, multiple transducers can be formed within a single axis, and across multiple axes on the same die substrate. In an exemplary embodiment, high frequency (e.g., 10 kHz to 20 kHz), middle frequency (e.g., 1 kHz to 10 kHz), and low frequency (e.g., less than or equal to 100 Hz to 1 kHz) may be formed within a single axis. In some embodiments, low frequency sensing transducers may measure a 1 Hz frequency, within a specific sensitivity range. Thus, each sensing transducer can be tuned to have a specific sensitivity to a specific frequency range, thereby spreading a uniform sensitivity across a broad frequency range. Additionally, this may enable sensitivity at frequency ranges that may not previously have been possible with microphones such as ECM. 
     In one aspect, MEMS vibration sensors incorporating vibration sensing transducer arrangements described herein may be used for outside noise rejection. For example, in additional to vocal cord vibration sensing as previously discussed, the vibration sensing transducers may be tuned to detect bone vibration, such as bone (e.g., jaw bone) vibration of a user&#39;s head. Accordingly, outside noise not originating from a user&#39;s bone vibration may be rejected. 
     In one aspect, MEMS microphone and vibration sensor dies, and/or the MEMS vibration sensors, described herein may be used for a variety of diagnostic applications, including motion, voice, and bio signal detection (e.g., heart beat, blood flow, motion, vibration, and other sounds) and machine operation (e.g., car engine, etc.). The MEMS microphone and vibration sensor dies and packages described herein may be incorporated into a variety of devices other than a remote controller, including, but not limited to, mobile telecommunication devices, ear buds, and a belt (e.g., wrist band, watch belt, ankle band, chest and back belt, etc.). 
     In utilizing the various aspects of the embodiments, it would become apparent to one skilled in the art that combinations or variations of the above embodiments are possible for forming a MEMS microphone and vibration sensor die and package. Although the embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the appended claims are not necessarily limited to the specific features or acts described. The specific features and acts disclosed are instead to be understood as embodiments of the claims useful for illustration. 
     While certain embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that the invention is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. The description is thus to be regarded as illustrative instead of limiting.

Metadata:
Filing Date: 20160125
Publication Date: 20170523
Grant Date: 20170523
Priority Date: 20151201
Inventors: HAN CALEB C.
ZHAI JUN
JIANG TONGBI T.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R31/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R19/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R19/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R31/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R19/005", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R19/005", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R19/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/46", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/46", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/04", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R19/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R2201/107", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1041", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R31/006", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 58708264