Abstract:
A micro electro-mechanical sensor is provided. The micro electro-mechanical sensor includes a substrate, and a conducting plane disposed on the substrate. A conducting via is disposed on the substrate, such as adjacent to the conducting plane. A plurality of ribbon conductors are disposed over the conducting plane and electrically connected to the conducting via, such that the plurality of ribbon conductors form a transducer array in combination with the conducting plane, such as through capacitive coupling that changes in response to changes in the physical shape of the plurality of ribbons.

Description:
The present application is a divisional of U.S. Ser. No. 12/054,169 filed Mar. 24, 2008, entitled “MICRO ELECTRO-MECHANICAL SENSOR (MEMS) FABRICATED WITH RIBBON WIRE BONDS” which is hereby incorporated by reference for all purposes. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to micro electro-mechanical sensors, and more specifically to a method and apparatus for a capacitive micro electro-mechanical sensor fabricated with ribbon wire bonds. 
     BACKGROUND OF THE INVENTION 
     The field of micro electro-mechanical devices is relatively new. While some micro electro-mechanical devices have been fabricated, the use of micro electro-mechanical devices has not been well developed, and applications for micro electro-mechanical devices are not well known. The best known micro electro-mechanical device may be the digital light projector (DLP) device, which is used to generate projected images. Sensors utilizing micro electro-mechanical devices are not generally known. 
     SUMMARY OF THE INVENTION 
     The current invention provides a micro electro-mechanical sensor. 
     In accordance with an exemplary embodiment of the present invention, a micro electro-mechanical sensor is provided. The micro electro-mechanical sensor includes a substrate, and a conducting plane disposed on the substrate. A conducting via is disposed on the substrate, such as adjacent to the conducting plane. A plurality of ribbon conductors are disposed over the conducting plane and electrically connected to the conducting via, such that the plurality of ribbon conductors form a transducer array in combination with the conducting plane, such as through capacitive coupling that changes in response to changes in the physical shape of the plurality of ribbons. 
     Those skilled in the art will further appreciate the advantages and superior features of the invention together with other important aspects thereof on reading the detailed description that follows in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a diagram of a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention; 
         FIG. 2  is a diagram of a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention; 
         FIG. 3  is a diagram of a method for manufacturing a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention; 
         FIG. 4  is a diagram of a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention; 
         FIG. 5  is a diagram of a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention; 
         FIG. 6  is a diagram of a method for monitoring a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention; 
         FIG. 7  is a diagram of a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention; and 
         FIG. 8  is a diagram of a system for controlling a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures might not be to scale, and certain components can be shown in generalized or schematic form and identified by commercial designations in the interest of clarity and conciseness. 
       FIG. 1  is a diagram of a micro electro-mechanical sensor  100  in accordance with an exemplary embodiment of the present invention. Micro electro-mechanical sensor  100  can use a multi-resonant array to detect and measure sound waves, pressure, force, acceleration, flow rate, or other physical forces. 
     Micro electro-mechanical sensor  100  includes a plurality of ribbon wires  102  that are bonded to conductive vias  104  and  106 , such as by wedge bonding or in other suitable manners. In one exemplary embodiment, ribbon wires  102  can be 6-10 micron thick gold ribbon wire that is 50-100 microns wide, and can be bonded side-by-side, approximately 50-100 microns apart, and vary in length from 100 to 1000 microns. Likewise, other suitable wires can be used, such as round wires or wires having other suitable dimensions that have a dynamic response to allow them to be used as sensor elements. 
     Ribbon wires  102  are mounted over conducting plane  108 , which is disposed on substrate  110 , to form an air gap  112 . In one exemplary embodiment, conductive vias  104  and  106  and conducting plane  108  can be formed in substrate  110  using chemical vapor deposition, direct metal deposition, or other suitable processes. Substrate  110  can alternatively be implemented as an organic printed circuit board, where conductive vias  104  and  106  and conducting plane  108  can be formed via subtractive or additive copper plating processes or by other suitable processes. Ribbon wires  102  can then be mounted utilizing wedge bonding or other suitable processes. Likewise, where round wires are utilized, wedge bonding, ball bonding, or other suitable round wire bonding processes can be utilized. 
     In operation, micro electro-mechanical sensor  100  provides a multi-resonant transducer array for detection and measurement of sound waves, pressure, force, acceleration, flow rate, or other physical forces. Changes in the shape of ribbon wires  102  can be detected by measuring the capacitance between ribbon wires  102  and conducting plane  108  or other suitable parameters, which can be correlated to sound waves, pressure, force, acceleration, flow rate, or other physical forces received at micro electro-mechanical sensor  100 . 
       FIG. 2  is a diagram of micro electro-mechanical sensor  200  in accordance with an exemplary embodiment of the present invention. Micro electro-mechanical sensor  200  includes a plurality of ribbon wires  202  that are bonded to conductive vias  204  and  206 , and which are disposed over conducting plane  208 . Conductive vias  204  and  206  and conducting plane  208  are disposed on substrate  210 . In one exemplary embodiment, conductive vias  204  and  206  and conducting plane  208  can be formed in substrate  210  using chemical vapor deposition, direct metal deposition, or other suitable processes. Ribbon wires  202  can then be mounted utilizing wedge bonding or other suitable processes. 
       FIG. 3  is a diagram of a method  300  for manufacturing a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention. Method  300  begins at  302 , where a substrate such as a silicon substrate or other suitable substrate is prepared. The method then proceeds to  304 , where a conducting plane and conducting vias are formed, such as by chemical vapor deposition, direct metal deposition, or other suitable processes. Additional devices can also or alternatively be formed, such as one or more transistors, diodes, capacitors, inductors, resistors, or other suitable devices. The method then proceeds to  306 . 
     At  306 , an insulation layer is deposited over the conducting plane or in other suitable locations, where suitable. The method then proceeds to  308  where the substrate is transferred to a wire bonder, such as a wedge bonder or other suitable bonders. The method then proceeds to  310  where a plurality of ribbon wires are bonded to the conductive vias, such as using wedge bonding or other suitable processes. The method then proceeds to  312 . 
     At  312 , the substrate is transferred to a tester, such as to test the resistance of the bonds, to test the capacitance of the array or individual elements of the array, or to perform other suitable tests. The method then proceeds to  314  where it is determined whether the test results are acceptable. If it is determined that the test results are not acceptable, the method proceeds to  316 , otherwise the method proceeds to  322  where a pass indication is generated. 
     At  316 , it is determined whether one or more elements of the multi-resonant array are inactive, such as where the multi-resonant array is provided with a number of spare elements that can be inactivated or compensated for. If it is determined that the failure is not due to a detectable number of inactive elements, the method proceeds to  318  where a fail indication for the micro electro-mechanical sensor is generated. Otherwise, the method proceeds to  320  where the failed elements, acceptable elements, or other suitable elements are identified. The micro electro-mechanical sensor can be categorized based on its capacitance, fusible links can be activated to isolate defective elements, or other suitable identification procedures can be utilized. 
     In operation, method  300  allows a micro electro-mechanical sensor to be fabricated, such as by using a combined deposition and wire bonding process or in other suitable manners. Method  300  further allows the micro electro-mechanical sensor to be tested to determine whether the micro electro-mechanical sensor meets predetermined parameters, to classify the micro electro-mechanical sensor based on predetermined parameters, or to otherwise perform post-manufacturing testing and classification of micro electro-mechanical sensors. 
       FIG. 4  is a diagram of a micro electro-mechanical sensor  400  in accordance with an exemplary embodiment of the present invention. Micro electro-mechanical sensor  400  can use a multi-resonant array to detect and measure sound waves, pressure, force, acceleration, flow rate, or other physical forces. 
     Micro electro-mechanical sensor  400  includes a plurality of ribbon wires  402  that are bonded to conductive vias  404  and  406 , such as by wedge bonding or in other suitable manners. In one exemplary embodiment, ribbon wires  402  can be 6-10 micron thick gold ribbon wire that is 50-100 microns wide, and can be bonded side-by-side, approximately 50-100 microns apart, and vary in length from 100 to 1000 microns. 
     Ribbon wires  402  are mounted over conducting plane  408  and insulation layer  412 , both of which are disposed on substrate  410 , and can include an air gap  414 . In one exemplary embodiment, conductive vias  404  and  406  and conducting plane  408  can be formed in substrate  410  using chemical vapor deposition, direct metal deposition, or other suitable processes. Insulation layer  412  can be formed using silicon dioxide deposition or other suitable processes, such as where an insulating material is provided that operates in conjunction with ribbon wires  402  to provide a multi-resonant transducer array. Insulation layer  412  can be shaped to provide predetermined dielectric properties where suitable. Ribbon wires  402  can then be mounted utilizing wedge bonding or other suitable processes. 
     In operation, micro electro-mechanical sensor  400  provides a multi-resonant transducer array for detection and measurement of sound waves, pressure, force, acceleration, flow rate, or other physical forces. Changes in the shape of ribbon wires  402  can be detected by measuring the capacitance between ribbon wires  402  and conducting plane  408  or other suitable parameters, which can be correlated to sound waves, pressure, force, acceleration, flow rate, or other physical forces received at micro electro-mechanical sensor  400 . Insulation layer  412  can be used to provide a physical barrier between ribbon wires  402  and conducting plane  408  so as to prevent inadvertent contact, can be used to modify the dielectric properties of air gap  414  or otherwise be used to modify the response of micro electro-mechanical sensor  400  to changes in pressure, sound, force, or other physical parameters, or can be used for other suitable purposes. 
       FIG. 5  is a diagram of micro electro-mechanical sensor  500  in accordance with an exemplary embodiment of the present invention. Micro electro-mechanical sensor  500  includes a plurality of ribbon wires  502  that are bonded to conductive vias  504  and  506 , and which are disposed over conducting plane  508 . Insulating layer  512  is provided to prevent inadvertent contact between ribbon wires  502  and conducting plane  508 , to provide suitable dielectric properties, or for other suitable purposes. Conductive vias  504  and  506 , conducting plane  508  and insulating layer  512  are disposed on substrate  510 . In one exemplary embodiment, conductive vias  504  and  506  and conducting plane  508  can be formed in substrate  510  using chemical vapor deposition, direct metal deposition, or other suitable processes, and insulating layer  512  can be formed using silicon dioxide deposition or other suitable processes. Ribbon wires  502  can then be mounted utilizing wedge bonding or other suitable processes. 
       FIG. 6  is a diagram of a method  600  for monitoring a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention. Method  600  begins at  602  where an initial parameter is measured. In one exemplary embodiment, the initial parameter can be total sensor capacitance, total sensor inductance, total sensor resistance, total sensor impedance, or other variables for a resonant sensor array. Likewise, the functionality of individual sensor ribbon wires, groups of sensor ribbon wires or other suitable parameters can be measured, where suitable. The method then proceeds to  604 . 
     At  604 , an operating parameter is measured. In one exemplary embodiment, the operating parameter can be the same parameter measured at  602 , or other suitable operating parameters can also or alternatively be measured, such as parameters derived from a measured signal, power consumption, current or voltage characteristics, or other suitable parameters. The method then proceeds to  606 . 
     At  606 , it is determined whether a change in the initial or operating parameters has occurred. In one exemplary embodiment, a comparison can be made between the initial and operating parameters where the same parameter is being measured. In another exemplary embodiment, additional testing can be performed where a first operating parameter, such as a change in the signal measured by the sensor, the power consumption of the sensor, the current or voltage characteristics of the sensor, or other suitable operating parameters, is used to determine whether a change in sensor operation has occurred, at which point additional testing can be performed to determine whether a ribbon wire, group of ribbon wires or other suitable components have shorted, have become an open circuit, or have otherwise become inoperable. If it is determined that no change has occurred, the method returns to  605 , otherwise the method proceeds to  608 . 
     At  608 , a parameter control is generated. In one exemplary embodiment, a ribbon wire that has shorted can be isolated or inactivated, such as by using a switching device, a fusible link, or other suitable devices. In another exemplary embodiment, the initial parameter can be re-determined, such as where the micro electro-mechanical sensor can be operated with a reduced number of ribbon wire elements. The method then proceeds to  610 , where the system configuration is updated, such as to modify signal processing parameters to utilize the micro electro-mechanical sensor with different sensor parameters, to reset the initial parameter, or in other suitable manners. The method then returns to  605 . Likewise, if it is determined that system operation can not continue due to sensor inoperability, an error signal or other suitable control can be generated to indicate that the sensor is no longer functional. 
     In operation, method  600  allows a micro electro-mechanical sensor to be utilized in a system for measuring sound, pressure, force, acceleration, flow rate or other suitable forces, so as to detect when sensor parameters have changed and to modify system operation or sensor configuration, where possible. Method  600  allows a micro electro-mechanical sensor or a system utilizing a micro electro-mechanical sensor to be dynamically configured during operation so as to avoid interruption of system operation. 
       FIG. 7  is a diagram of micro electro-mechanical sensor  700  in accordance with an exemplary embodiment of the present invention. Micro electro-mechanical sensor  700  includes a plurality of ribbon wires  702  that are bonded to conductive vias  704  and  706 , and which are disposed over conducting plane  708 . Conductive vias  704  and  706  and conducting plane  708  are disposed on substrate  710 . In one exemplary embodiment, conductive vias  704  and  706  and conducting plane  708  can be formed in substrate  710  using chemical vapor deposition, direct metal deposition, or other suitable processes. Ribbon wires  702  can then be mounted utilizing wedge bonding or other suitable processes. 
     Micro electro-mechanical sensor  700  includes devices  712  and controllers  714  and  716 , which can also be formed using chemical vapor deposition or other suitable processes. In one exemplary embodiment, devices  712  can be switches, transistors, or other suitable devices that allow individual ribbon wires  702  or groups of ribbon wires  702  to be switched in or out of a multi-resonant sensor array in response to control signals received from controllers  714  and  716 . In another exemplary embodiment, devices  712  can be fusible links or other suitable devices that allow individual ribbon wires  702  or groups of ribbon wires  702  to be isolated, such as where individual ribbon wires  702  or groups of ribbon wires  702  have shorted or otherwise become inoperable. 
     In operation, micro electro-mechanical sensor  700  provides additional controls to allow individual ribbon wires  702  or groups of ribbon wires  702  to be selectively included in or excluded from a multi-resonant array of ribbon wires. Micro electro-mechanical sensor  700  can be used in systems where a change in the operating parameters of the sensor is required or utilized, can be used to allow continued operation of a system utilizing micro electro-mechanical sensor  700  in the event of a non-catastrophic failure of micro electro-mechanical sensor  700 , or can be used in other suitable applications. 
       FIG. 8  is a diagram of a system for controlling a micro electro-mechanical sensor in accordance with an exemplary embodiment of the present invention. Transducer controller  800  includes transducer measurement system  802 , element failure detector  804  and transducer configuration system  806 , each of which can be implemented in hardware, software, or a suitable combination of hardware and software, and which can be one or more software systems operating on a suitable processing platform. As used herein, “hardware” can include a combination of discrete components, an integrated circuit, an application-specific integrated circuit, a field programmable gate array, a digital signal processor, or other suitable hardware. As used herein, “software” can include one or more objects, agents, threads, lines of code, subroutines, separate software applications, two or more lines of code or other suitable software structures operating in two or more software applications or on two or more processors, or other suitable software structures. In one exemplary embodiment, software can include one or more lines of code or other suitable software structures operating in a general purpose software application, such as an operating system, and one or more lines of code or other suitable software structures operating in a specific purpose software application. 
     Transducer controller  800  is coupled to a suitable micro electro-mechanical sensor. As used herein, the term “coupled” and its cognate terms such as “couples” or “couple,” can include a physical connection (such as a wire, optical fiber, or a telecommunications medium), a virtual connection (such as through randomly assigned memory locations of a data memory device or a hypertext transfer protocol (HTTP) link), a logical connection (such as through one or more semiconductor devices in an integrated circuit), other suitable connections, or a suitable combination of connections. 
     Transducer measurement system  802  receives transducer data from a micro electro-mechanical sensor and generates measurement data defining one or more parameters of the micro electro-mechanical sensor. In one exemplary embodiment, transducer measurement system  802  can determine a number of ribbon wires in a multi-resonant array, such as by measuring a capacitance of the multi-resonant array, a number of active ribbon wires, or other suitable parameters. Transducer measurement system  802  can also or alternatively measure a voltage or voltage waveform, a current or current waveform, an impedance, a resistance, an inductance, a number of activated devices such as fusible links, or other suitable parameters, and can generate data identifying the measured parameter, such as for use by a system that utilizes the micro electro-mechanical sensor. 
     Element failure detector  804  receives data from a micro electro-mechanical sensor and determines whether a failure of the micro electro-mechanical sensor or one or more components of the micro electro-mechanical sensor has occurred. In one exemplary embodiment, element failure detector  804  can determine a number of ribbon wires in a multi-resonant array, such as by measuring a capacitance of the multi-resonant array, a number of active ribbon wires, or other suitable parameters, and can compare that number to a previously-determined number of ribbon wires, such as one determined by transducer measurement system  802 . Element failure detector  804  can also or alternatively measure a voltage or voltage waveform, a current or current waveform, an impedance, a resistance, an inductance, a number of activated devices such as fusible links, or other suitable parameters, and can generate data identifying a change in the measured parameter, such as to indicate that a component of a micro electro-mechanical sensor or the entire micro electro-mechanical sensor has failed. 
     Transducer configuration system  806  receives micro electro-mechanical sensor failure data, system configuration data or other suitable data and generates control data for a micro electro-mechanical sensor, a system utilizing a micro electro-mechanical sensor, or other suitable data. In one exemplary embodiment, transducer configuration system  806  can reconfigure a micro electro-mechanical sensor to compensate for one or more failed ribbon wires or other components, such as by isolating the failed component utilizing switches, fusible links, or other suitable devices. In another exemplary embodiment, transducer configuration system  806  can control a configuration of a micro electro-mechanical sensor, such as by selectively operating one or more ribbon wires or groups of ribbon wires in a multi-resonant array or other suitable components. 
     In operation, transducer controller  800  allows a micro electro-mechanical sensor, such as a multi-resonant array of ribbon wires or other suitable micro electro-mechanical sensors, to be used in a system that receives and processes signals from the micro electro-mechanical sensor, such as to measure sound, force, pressure, acceleration, flow rate, or other suitable physical forces. Transducer controller  800  allows a micro electro-mechanical sensor to be dynamically monitored, configured or otherwise controlled. 
     Although exemplary embodiments of a method and apparatus of the present invention have been described in detail herein, those skilled in the art will also recognize that various substitutions and modifications can be made to the method and apparatus without departing from the scope and spirit of the appended claims.