Patent Publication Number: US-10322931-B2

Title: Dry scribing methods, devices and systems

Description:
BACKGROUND 
     Technical Field 
     The present disclosure relates generally to scribe lines for separating dies on a semiconductor wafer, and more specifically to dry scribing utilizing scribe lanes or trenches in separating the dies on the semiconductor wafer. 
     Description of the Related Art 
     An acoustic transducer, such as a microelectromechanical systems (MEMS) microphone of a capacitive type, generally includes a detection structure or sensor having a moveable or mobile electrode in the form of a diaphragm or membrane that is arranged facing a fixed electrode. The two electrodes together form the plates of a capacitor. The mobile electrode is generally anchored to a substrate at a perimeter portion of the mobile electrode. A central portion of the mobile electrode is not anchored to the substrate but is suspended over a cavity or chamber formed in the substrate, and is free to move or bend in response to the pressure of a sound wave incident upon a surface of the mobile electrode. Since the mobile electrode and the fixed electrode form a capacitor, bending of the membrane that forms the mobile electrode causes a variation in the value of the capacitance of the capacitor formed by the mobile and fixed electrodes. In operation, sound waves incident upon the mobile electrode cause variations in the capacitance of the MEMS microphone. These variations in capacitance are converted into an electrical signal indicative of the incident sound wave, and this electrical signal is supplied as an output signal of the MEMS microphone. 
     The manufacturing of MEMS microphones may be done through conventional semiconductor processing techniques. Thus, as with the formation of conventional integrated circuits, the manufacturing of the sensor includes the formation of a number of the sensors on a semiconductor wafer. Each of these sensors may be termed a die on the semiconductor wafer and must be separated as part of forming the individual sensors for individual MEMS microphones. Typically, separating or dicing these individual sensors is done through a laser cutting process and there is a need for improving this laser cutting process. 
     BRIEF SUMMARY 
     One embodiment of the present disclosure is directed to a transducer including a first substrate and an integrated circuit coupled to the first substrate. A sensor is electrically coupled to the integrated circuit and includes a second substrate having a first surface and a second surface opposite the first surface. The second substrate has scribe boundaries defining an outer edge of the second substrate and includes at least one chamber extending from the first surface towards but not reaching the second surface. At least one chamber extends from the second surface towards the first surface to meet the at least one chamber extending from first surface. Scribe trenches are formed in the second surface at the scribe boundaries, each scribe trench having a width extending from the scribe boundary towards the at least one chamber extending from the second surface towards but not reaching the at least one chamber extending from the second surface. At least one membrane extends over the first surface of the second substrate and each membrane extends over a respective at least one chamber extending from first surface. At least one plate extends from the first surface of the second substrate over a corresponding one of the at least one membranes. 
     Another embodiment of the present disclosure is directed to a method of forming semiconductor devices, such as capacitive type MEMS acoustic transducers, in a semiconductor wafer. The method includes forming a mask layer on a back surface of the semiconductor wafer and removing first etch portions of the mask layer and scribe trench portions of the mask layer. Each scribe trench portion is positioned in the mask layer to define a corresponding scribe boundary of a plurality of the semiconductor devices being formed in the semiconductor wafer. Etching the semiconductor wafer through the first etch portions and the scribe trench portions may be done simultaneously to form external back chambers and scribe trenches, respectively, in the semiconductor wafer. The semiconductor wafer is then cut along cutting lines in the scribe trenches to singulate individual MEMS acoustic transducers. Prior to etching the semiconductor wafer through the first etch portions and the scribe trench portions, the method includes removing second etch portions of the mask layer and etching the semiconductor wafer through the second etch portions to form internal back chambers. The etching through the first and second etch portions and the scribe trench portions are dry etching of the semiconductor substrate in one embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE FIGURES 
       One or more embodiments will now be described, by way of example only, with reference to the annexed figures, in which: 
         FIG. 1  is a simplified cross-sectional view of a MEMS acoustic transducer or microphone including a sensor formed according to embodiments of the present disclosure. 
         FIG. 2  is a top view of a semiconductor wafer including a number of the sensors of  FIG. 1  with scribe trenches formed between the sensors according to one embodiment of the present disclosure. 
         FIG. 3A  is a bottom view of a portion of the semiconductor wafer of  FIG. 2  showing back chambers of one sensor substrate along with scribe trenches formed between adjacent sensor substrates according to one embodiment of the present disclosure. 
         FIG. 3B  is cross-sectional perspective view of a portion of the semiconductor wafer of  FIG. 2  showing the back chambers of one sensor substrate along with the scribe trenches formed between adjacent sensor substrates according to one embodiment of the present disclosure. 
         FIG. 4A  is a cross-sectional view showing a process for the formation of the internal back chambers and preparation for forming the external back chamber and scribe trenches for one of the sensors in the semiconductor wafer of  FIG. 2  according to one embodiment of the present disclosure. 
         FIG. 4B  is a cross-sectional view showing a process for the formation of the scribe trenches along with the external back chamber for the sensor of  FIG. 4A  after formation of the internal back chambers according to an embodiment of the present disclosure. 
         FIG. 5  is a cross-sectional view showing portions of adjacent sensors in the semiconductor wafer of  FIG. 2  and laser cutting along one of the scribe trenches formed between these adjacent sensors according to one embodiment of the present disclosure. 
         FIG. 6  is a cross-sectional view showing a portion of one of the sensors of  FIG. 5  and the scribe boundary of this sensor formed by the laser cutting along the scribe trench of  FIG. 5 . 
         FIG. 7  is a cross-sectional view showing portions of adjacent sensors in a semiconductor wafer and conventional laser cutting of these adjacent sensors. 
         FIG. 8  is a cross-sectional view showing a portion of one of the sensors of  FIG. 7  and a scribe boundary of this sensor formed by the conventional laser cutting of  FIG. 7 . 
         FIG. 9  is a functional block diagram of an electronic device including the MEMS microphone of  FIG. 1  according to a further embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a simplified cross-sectional view of a MEMS acoustic transducer or microphone  100  including a detection structure or sensor  102  formed according to embodiments of the present disclosure. The sensor  102  includes a sensor body or substrate  104  having scribe trench portions  106  extending inward from scribe boundaries  108  of the substrate. The scribe trench portions  106  result from scribe trenches and subsequent laser cutting along these scribe trenches during the manufacture of the sensor  102 , as will be described in more detail below. These scribe trenches reduce the time required to fabricate the sensor  102  and the resulting scribe trench portions  106  can help reduce the size of a package  110  housing the sensor  102  and an application specific integrated circuit (ASIC)  111  of the MEMS microphone  100 , as will also be described in more detail below. 
     In the present description, certain details are set forth in conjunction with the described embodiments to provide a sufficient understanding of the present disclosure. One of ordinary skill in the art will appreciate, however, that embodiments of the present disclosure may be practiced without these particular details. Furthermore, one of ordinary skill in the art will appreciate that the present disclosure is not limited to the example embodiments described herein, and will also understand that various modifications, equivalents, and combinations of the disclosed embodiments, and components thereof, are within the scope of the present disclosure. Embodiments including fewer than all the components of any of the respective described embodiments may also be within the scope of the present disclosure although not expressly described in detail herein. Also, the operation of well-known components, structures, and/or processes has not been shown or described in detail below to avoid unnecessarily obscuring the present disclosure. Also, in the drawings, identical reference numbers identify similar elements or acts while the sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged, or may be positioned to improve drawing legibility or to more clearly illustrate a particular aspect of the present disclosure. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements, and may have been solely selected for ease of illustration or description in the drawings. Finally, note that in the description below where more than one of a particular type of element or component is shown in the figures, each such component may be labeled with a corresponding reference number and letter. In this situation, when referring to a particular one or ones of the components both the number and letter designations will be utilized, while the letter designation will be omitted when referring to any or all of the components. 
     In the sensor  102 , the sensor substrate  104  is typically made of a semiconductor material such as silicon. The sensor  102  includes movable electrodes membranes  112   a    112   b , each membrane being flexible so as to experience a deformation or movement in response to incident acoustic pressure or sound waves. Each membrane  112   a ,  112   b  extends over a corresponding opening or internal back chamber  114   a ,  114   b  in the substrate  104  and is fixed at its ends to the substrate. Forming the membranes  112   a ,  112   b  extending over the internal back chambers  114   a  and  114   b  allows the membranes to flex or move responsive to the incident acoustic waves. Each membrane  112   a ,  112   b  is typically formed from a conductive material, such as polysilicon, having a suitable thickness to provide the desired flexibility of the membrane. Other suitable structures may be utilized for each membrane  112   a ,  112   b , such as an insulating layer having a suitable flexibility with a conductive layer formed on the insulating layer or portions of the insulating layer. The sensor  102  further includes an external opening or external back chamber  116 , with the internal back chambers  114   a ,  114   b  in combination with the external back chamber forming the back chamber of the sensor, as will be discussed in more detail below. 
     The sensor  102  further includes fixed electrodes or back plates  118   a  and  118   b  positioned proximate the membranes  112   a  and  112   b , respectively. Each back plate  118   a ,  118   b  is also attached at its ends to the substrate  104 , but unlike the membrane is formed from a suitably rigid material such that the back plate experiences no movement or deformation in response to incident acoustic waves. Typically, each back plate  118  is formed from an insulating layer having a suitable rigidity, such as a nitride layer, with a suitable conductive layer like polysilicon formed on the nitride layer or portions thereof. In addition, each back plate  118  includes openings or holes  120  formed in the back plate to allow acoustic waves to propagate from a front chamber  122  of the sensor  102  through the back plate and over the membranes  112  to the back chamber  116 , as will be described in more detail below. 
     In the MEMS microphone  100 , the substrate  104  of the sensor  102  is physically attached to an acoustic transducer or microphone substrate  124  in a suitable manner, such as through an adhesive layer  126  formed on an upper surface of the microphone substrate. The ASIC  111  is also physically attached to the microphone substrate  124  through the adhesive layer  126 . The ASIC  111  includes suitable electronic circuitry for processing a sensor signal generated by the sensor  102  and provides a microphone output signal having a value that is a function of an acoustic wave incident upon the MEMS microphone  100 . The ASIC  111  is electrically connected through bonding wires  128 , one of which is shown in  FIG. 1 , to the sensor  102  to receive the sensor signal. The ASIC  111  is further coupled through bonding wires  128 , again only one of which is shown in  FIG. 1 , to contact pads  130  on the upper surface of the microphone substrate  124 . The microphone substrate  124  includes one or more conductive layers (not shown) that electrically couple contact pads  130  on the upper surface of the microphone substrate to contact pads  132  on a lower surface of the microphone substrate. The MEMS microphone  100  is electrically coupled to external electronic circuitry (not shown) through the contact pads  132  on the lower surface of the microphone substrate  124 . 
     As seen in  FIG. 1 , the ASIC  111  is positioned on the microphone substrate  124  underneath an aperture  134  on the upper or top surface of the package  110 . The aperture  134  is termed a “top acoustic port” because acoustic waves  136  that propagate through the top acoustic port are sensed by the MEMS microphone  100 . The ASIC  111  includes a protective layer  138  formed on top of the ASIC to protect the ASIC from light and other environmental factors surrounding the MEMS microphone  100  that could possibly adversely affect the ASIC. Acoustic waves  136  traveling through the top acoustic port  134  enter an internal cavity  140  defined by the package  110  and the microphone substrate  124  with the sensor  102  and ASIC  111  mounted thereon. 
     In operation of the MEMS microphone  100 , a portion of acoustic waves  136  traveling downward in  FIG. 1  propagate through the top acoustic port  134  and into the internal cavity  140 . The acoustic waves  136  propagating through the top acoustic port  134  then reflect off the protective layer  138 , with a portion of these reflected acoustic waves being directed towards the right to the front chamber  122  of the sensor  102 . A portion of the reflected acoustic waves  136  in the front chamber  122  thereafter propagate through the holes  120  in the back plates  118  and impinge upon or are incident on the membranes  112  of the sensor  102 . The membranes  112  and back plates  118  form a variable capacitance having a value that varies as a function of the acoustic waves  136  that propagate through the front chamber  122  and the holes  120  in the back plates  118  and are incident upon the membranes. 
     The acoustic waves  136  incident upon the membranes  112  cause the membranes to deform or move relative to the back plates  118 , which causes a variation in the gap or distance between the membranes and the back plates and thereby a variation in the capacitance formed by the back plates and the membranes. The ASIC  111  applies an electrical signal across the variable capacitance formed by the membranes  112  and back plates  118  and detects variations in this electrical signal which varies as a function of the capacitance and thereby as a function of the acoustic waves  136  incident upon the membranes. The ASIC  111  processes the electrical sensor signal from the sensor  102  to generate the microphone output signal that is provided on contact pads  132  of the MEMS microphone  100  to external electronic circuitry (not shown) for utilization by that external circuitry. 
     The performance of the MEMS microphone  100  depends upon the volume of the back chamber, which includes the volumes of the internal chambers  114   a  and  114   b  and the external chamber  116 , and the volume of the front chamber  122 . More specifically, the volume of the front chamber  122  determines an upper resonance frequency of the MEMS microphone  100  and thereby determines the performance of the MEMS microphone at high frequencies of the acoustic waves  136 . In general, the smaller the volume of the front chamber  122  the higher the upper cut-off frequency of the MEMS microphone  100 . Regarding the back chamber of the sensor  102 , a larger volume for the back chamber improves the frequency response and the sensitivity of the MEMS microphone  100 . This is why dual internal chambers  114   a  and  114   b  in combination with the external chamber  116  are utilized in the sensor  102 . The external chamber  116  extends in a horizontal direction, namely parallel to the upper surface of the microphone substrate  124 , to a greater extent than do the internal chambers  114   a  and  114   b , which increases the overall volume of the back chamber of the sensor  102 . 
     The present disclosure is directed to methods of forming the sensor  102  and the sensor including the scribe trench portions  106  formed according to these methods. Therefore, the detailed structure and operation of the sensor  102  as well as the detailed structure and operation of the ASIC  111  in processing the sensor signal from the sensor will not be described in more detail herein. The details regarding these structures and operation will be understood by those skilled in the art. For example, U.S. Patent Application Publication No. US2014/0353780A1 describes in detail the structure and operation of a detection structure or sensor for a MEMS microphone, and this reference is hereby incorporated herein in its entirety to the extent the disclosure in this reference is not inconsistent with the present disclosure. In the sensor  102 , for example, the particular shapes and structures of the membranes  112   a ,  112   b  and the back plates  118   a ,  118   b  may vary in different embodiments of the sensor. 
     Referring now to  FIG. 2 , this figure is a top view of a semiconductor wafer  200  including a number of integrated circuits  202  formed on the wafer with scribing streets  204  formed between the integrated circuits according to one embodiment of the present disclosure. Only some of the scribing streets  204  are labeled in  FIG. 2  to simplify the figure. The integrated circuits  202  are singulated from the semiconductor wafer  200  through a laser cutting process along the scribing streets  204 , as will be described in more detail below. Each of these singulated integrated circuits is a die including the required components to form one of the sensors  102  of  FIG. 1 . Each of the scribing streets  204  has a width W and includes a scribe trench, which is represented in  FIG. 2  as a dotted line  206  for several of the scribing streets. As will be described in more detail, the laser cutting of the semiconductor wafer  200  occurs along the scribe trenches  206 . In lieu of laser cutting, singulation of the integrated circuits could be done through another dry cutting process such as with a diamond blade. 
       FIG. 3A  is a bottom view of a portion of the semiconductor wafer  200  of  FIG. 2  showing the semiconductor substrate  104  including the dual internal back chambers  114   a  and  114   b  and the external back chamber  116  of one sensor  102  before the sensor has been singulated from the semiconductor wafer.  FIG. 3A  also labels the scribing street  204  having the width W to the right of the back chambers  114  and  116  and shows the scribe trenches  206  running along the top, bottom left and right of the back chambers. A portion of the semiconductor substrates  104  to the left and right of the labeled semiconductor substrate in the middle are also seen in  FIG. 3A .  FIG. 3B  is a cross-sectional perspective view of a portion of the semiconductor wafer  200  of  FIG. 2  again showing the semiconductor substrate  104  including the dual internal back chambers  114   a  and  114   b  and the external back chamber  116  of one sensor  102  before the sensor has been singulated from the semiconductor wafer. As seen in  FIG. 3B , the illustrated portion of the semiconductor substrate  200  includes a surface layer  300  shown on the bottom of the figure. This surface layer  300  is present during fabrication of the scribe trenches  206  and internal back chambers  114  and external back chamber  116  but will of course later be removed during subsequent fabrication steps such as formation of the membranes  112  and back plates  118 , with these components having been previously described with reference to  FIG. 1 . 
     By including the scribe trenches  206  in the scribing streets  204  between the integrated circuits  202 , the time required to singulate the integrated circuits to thereby form respective sensors  102  is reduced. In addition, the scribe trenches  206  result in the semiconductor substrate  104  of each sensor  102  including the scribe trench portions  106  ( FIG. 1 ), which improves a tolerance T from scribe boundaries  108  of the substrate and thereby reduces the overall size of the sensor  102 . The reduced singulation time resulting from the scribe trenches  206  and the scribe trench portions  106  will be discussed in more detail below with reference to  FIGS. 7 and 8 . 
       FIG. 4A  is a cross-sectional view showing a process for the formation of the internal back chambers  114  and preparation for forming the external back chamber  116  and scribe trenches  206  for one of the sensors  102  in the semiconductor wafer  200  of  FIG. 2  according to one embodiment of the present disclosure. Initially, a suitable mask layer  400  is formed on the upper surface of the semiconductor substrate  104 . The mask layer  400  may be any suitable type of mask layer, such as a silicon dioxide layer formed using Tetraethyl Orthosilicate (TEOS) or an undoped silicate glass (USG) layer. The internal back chambers  114  are formed through a deep silicon etch of the semiconductor substrate  104 . 
     Prior to performing this deep silicon etch, internal back chamber portions  402  of the mask layer  400  are removed. Although shown in  FIG. 4A , at this point in the process an external back chamber portion  404  and scribe trench portion  406  of the mask layer  400  have not yet been removed such that the mask layer  400  covers the upper surface of the semiconductor substrate  104  except for the internal back chamber portions  402 . Thus, with the internal back chamber portions  402  of the mask layer  400  having been removed a deep silicon etch is performed on the semiconductor substrate  104  to form the internal back chambers  114 . After formation of the internal back chambers  114 , the external back chamber portion  404  and scribe trench portion  406  of the mask layer  400  are then removed as shown in  FIG. 4A . A structure  408  formed on a lower surface of the semiconductor substrate  104  is also illustrated in  FIG. 4A . This structure  408  is associated with the formation of additional components of the sensor  102  being formed, such as layers associated with the membranes  112  and back plates  118 , which have already been formed at this point in the fabrication process of the sensor  102  according to the illustrated embodiment. 
     Once the external back chamber portion  404  and the scribe trench portion  406  of the mask layer  400  have been removed as illustrated in  FIG. 4A , a second silicon etch of the semiconductor substrate  104  is then performed to thereby simultaneously form the external back chamber  116  and scribe trench  206  as illustrated in  FIG. 4B . In this way, the formation of the scribe trenches  206  does not require the formation of any additional mask layers during fabrication of the sensor  102 . The existing mask layer  400  utilized to form the internal back chambers  114  and external back chamber  116  is instead also utilized in forming the scribe trenches  206 . In one embodiment, this pre-laser cutting second silicon etch is a dry silicon etch at the front-end of the process and which makes the subsequent dicing step through the laser cutting shorter, and increases tolerances the sensor  102  as will be described in more detail below. 
     Moreover, in forming the scribe trenches  206  in this way the duration of the process is not undesirably lengthened to form the scribe trenches  206 . One skilled in the art will understand suitable silicon etching processes for forming both the internal back chambers  114  and the external back chamber  116  and scribe trenches  206 . In one embodiment, a deep dry silicon etch having suitable process parameters is utilized in forming the chambers  114 ,  116  and scribe trenches  206 . 
       FIG. 5  is a cross-sectional view showing portions of adjacent sensors  102  in the semiconductor wafer  200  of  FIG. 2  and showing laser cutting along one of the scribe trenches  206  formed between these adjacent sensors according to one embodiment of the present disclosure. The laser cutting along the scribe trench  206  occurs along a laser cutting line  500  in approximately the center of the scribe trench as shown. Because of the scribe trench  206 , the semiconductor substrate  104  has a thickness or depth d at the point of the laser cutting line  500  that is less than an overall thickness or depth of the semiconductor substrate, as seen for the portions of the semiconductor substrate to the left and right of the scribe trench. This reduced depth d at the laser cutting line  500  means that the time to perform the laser cutting along the laser cutting line is reduced. This improves the overall process of fabricating the sensors  102  by reducing the time it takes to singulate the sensors from the semiconductor wafer  200 . Furthermore, the scribe trench  206  and reduced depth d that must be cut through on the cutting line  500  means that fewer unwanted particles are generated during this laser cutting process. Fewer particles is desirable because these particles and land on unwanted places on the semiconductor wafer  200  and sensors  102  being formed thereon and interfere with the proper operation of sensor  102  after singulation, as will be appreciated by those skilled in the art. In  FIG. 5 , portions of one of the membranes  112  and back plate  118  are also shown in  FIG. 5  for each of the sensors  102  illustrated in the figure. A diameter of the laser that cuts the semiconductor substrate  104  along the cutting line  500  defines a width of the cutting line and this width of the cutting line is significantly less than a width of the scribe trench  206  such that the scribe trench portions  106  are formed during the laser cutting as shown in  FIGS. 1 and 6 . 
       FIG. 6  is a cross-sectional view showing a portion of one of the sensors  102  of  FIG. 5  and the scribe boundary  108  (see  FIG. 1 ) of this sensor formed by the laser cutting along the laser cutting line  500  in the scribe trench  206  of  FIG. 5 . Also shown in  FIG. 6  is a portion of the microphone substrate  124  on which the sensor  102  is mounted as previously described with reference to  FIG. 1 . The laser cutting along the laser cutting line  500  forms the scribe boundary  108  of the semiconductor substrate  104  of the singulated sensor  102  and the semiconductor substrate  104  also includes the scribe trench portion  106 , as previously described with reference to  FIG. 1 . As seen in  FIG. 6 , the dual internal back chambers  114  extend to a depth (i.e., vertically in  FIG. 6 ) from the front surface of the semiconductor substrate  104  and partially towards the back surface of the substrate. The external back chamber  116  extends from the back surface of the semiconductor substrate  104  towards the front surface of the substrate and to a depth sufficient to meet the dual internal back chambers  114 . The scribe trench portions  106  are formed in the back surface of the semiconductor substrate  104  at the scribe boundaries  108 . Each scribe trench portion has a width extending laterally (i.e., from left-to-right in  FIG. 6 ) from the scribe boundary  108  towards the external back chamber  116 , but the width of the scribe trench portion  106  is such that the scribe trench portion does not meet the external back chamber  116 . Each scribe trench portion  106  has a depth extending from the back surface of the substrate  104  towards the front surface of the substrate that is approximately equal to the depth of the external back chamber  116  from the back surface of the substrate. 
     Due to the presence of the scribe trench portion  106 , the tolerance T from which a contact pad  600  shown covered with solder paste  602  results in the contact pad being closer to the scribe boundary  108  that is possible and conventional MEMS sensors. This is true because the tolerance T is measured from an interior vertical portion of the scribe trench portion  106  furthest from the scribe boundary  108  instead of from the scribe boundary itself as in conventional MEMS sensors. Thus, the overall size of the package  110  of the MEMS microphone  100  of  FIG. 1  may be reduced since these contact pads  600  may be positioned closer to the scribe boundary  108  of the semiconductor substrate  104  of the sensor  102 . Thus, the scribe trench portions  106  formed in the semiconductor substrate  104  of the sensor  102  reduce the effective die footprint of the sensor, allowing larger tolerances in back end processes such as electrical interconnections to the sensor  102 , ASIC  111  and microphone substrate  124 . In addition, where the adhesive layer  126  ( FIG. 1 ) is a glue layer the scribe trench portions  106  provide better glue containment during placement of the die (i.e., the singulated sensor  102 ). 
       FIGS. 7 and 8  illustrate conventional laser cutting to singulate MEMS sensors. As seen in  FIG. 7  the depth d of a semiconductor substrate  702  that must be cut through the laser cutting process corresponds to the entire thickness of the semiconductor substrate and would therefore take a longer time to perform in comparison to the cutting process described with reference to the structure of  FIG. 5 .  FIG. 8  shows a scribe boundary  800  of the conventional singulated MEMS sensor and shows how the tolerance T from the scribe boundary must be maintained relative to a contact pad  802 , once again showed covered in solder paste  804 , on a microphone substrate  806 , increasing the size of a MEMS microphone including this conventional sensor structure. 
     Although embodiments of the present disclosure have been described as being directed to capacitive type MEMS acoustic sensors or microphones, the present disclosure is not limited to these embodiments. For example, the concepts described above may be applied to different types of devices other than MEMS microphones, such as digital micromirror devices (DMDs) and more generally to devices that require a dry dicing method, such as laser cutting, and having a back surface or side trench etch. The front surface or side of the sensor  102  is the side on which the membranes  114  and back plates  118  are formed while the back side of the sensor is the side on which the external back chamber  116  and scribe trenches  206  are formed. 
       FIG. 9  is a functional block diagram of an electronic device  900  including the MEMS microphone  100  of  FIG. 1  according to a further embodiment of the present disclosure. The electronic device  900  includes processing circuitry  904  that is coupled to the MEMS microphone  100  to receive a signal indicative of acoustic waves sensed by the microphone, as previously discussed with reference to  FIG. 1 . The MEMS microphone  100  in the electronic device  900  may have a “top port” configuration as does the embodiment of  FIG. 1  with the top acoustic port  134 , but may also have different configurations in different embodiments of the disclosure. The MEMS microphone  100  could, for example, have a bottom port configuration where the acoustic port  134  is located on a bottom surface of the package  110  in different embodiments of the electronic device  900 . 
     The processing circuitry  904  also controls the overall operation of the electronic device and also executes applications or “apps”  906  that provide specific functionality for a user of the electronic device  900 . A power management subsystem  908  of the electronic device  900  is coupled to the processing circuitry  904  and may include a battery for powering the electronic device  900  and also control circuitry for controlling power-related operating modes of the device such as charging of the battery, power-savings modes of operation, and so on. The electronic device  900  further includes a video component such as a touch screen  910  with a touch display (not shown) such as a liquid crystal display (LCD) and a touch panel (not shown) attached to or formed as an integral part of the touch display. In operation, the touch screen  910  senses touches of a user of the electronic device  900  and provides sensed touch information to the processing circuitry  904  to thereby allow the user to interface with and control the operation of the electronic device. The processing circuitry  904  also controls the touch screen  910  to display desired visual content on the touch display portion of the touch screen. 
     The electronic device  900  further includes data storage or memory  912  coupled to the processing circuitry  904  for storing and retrieving data including the apps  906  and other software executing on the processing circuitry and utilized by the electronic device during operation. Examples of typical types of memory  912  include solid state memory such as DRAM, SRAM and FLASH, solid state drives (SSDs), and may include any other type of memory suited to the desired functionality of the electronic device  900  including digital video disks (DVDs), compact disk read-only (CD-ROMs), compact disk read-write (CD-RW) memories, magnetic tape, hard and floppy magnetic disks, tape cassettes, and so on. 
     Input devices  914  are coupled to the processing circuitry  904  and may include a keypad, whether implemented through the touch screen  910  or separately, a pressure sensor, accelerometer, keyboard, mouse, digital camera to capture still and video images, and other suitable input devices. The MEMS microphone  100  may be considered one of the input devices  914 . Output devices  916  are coupled to the processing circuitry  904  and may include, for example, audio output devices such as a speaker, printer, vibration device, and so on. The input devices  914  and output devices  916  collectively may include other types of typical communications ports for the electronic device  900 , such as USB ports, HDMI ports, and so on. The electronic device  900  further includes communications subsystems  918  coupled to the processing circuitry  904  and which may include Wi-Fi, GPS, cellular and Bluetooth subsystems for providing the device with the corresponding functionality. 
     The specific type and number of input devices  914 , output devices  916 , communications subsystems  918 , and even the specific functionality of the power management subsystem  908  will of course depend on the type of the electronic device  900 , which may be any suitable type of electronic device or system. The electronic device  900  is in one embodiment a mobile-communications device, such as, for example, a cell phone, smart phone, personal digital assistant (PDA), a laptop computer such as a notebook or ultrabook computer, a personal computer system, a voice recorder, a reader of audio files with voice-recording capacity, and so on. Alternatively, the electronic device  900  may be a hydrophone capable of working under water. 
     The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.