Patent Publication Number: US-2013249542-A1

Title: Foldable substrate

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     N/A 
     BACKGROUND OF THE INVENTION 
     In many devices, for example, cellular phones, personal navigation devices, etc., sensing along an out of plane functional axis is required in an integrated package. These devices, however, are fabricated using semiconductor processes but because of the two dimensional nature of semiconductor processes, an out of plane structure is very difficult to produce. In many cases, therefore, MEMS, or other non-traditional fabrication processes, are employed. The use of such methods, however, make the device more expensive and require longer development cycles. 
     What is needed, therefore, is an accurate field sensor, e.g., a magnetic field sensor, that includes out of plane functionality, that is small in size, low in cost, and is easily incorporated into a device. 
     BRIEF SUMMARY OF THE INVENTION 
     An embodiment of the present invention is directed to a foldable substrate comprising a first substrate portion having a first upper surface and a second substrate portion having a second upper surface. A foldable bridge portion couples the first substrate portion to the second substrate portion and the foldable bridge portion includes a coupling strip extending from the first substrate portion to the second substrate portion and a gap corresponding to a portion of the coupling strip and defined between the first and second substrate portions. 
     A method of manufacturing a foldable substrate includes providing a wafer substrate having a wafer body portion, an upper surface and a lower surface and defining a first substrate portion and a second substrate portion of the wafer substrate. A foldable bridge portion is provided to extend from the first substrate portion to the second substrate portion; and portions of the wafer body portion are removed to create a gap corresponding to at least a portion of the foldable bridge portion. 
     Further, a foldable substrate comprises a first substrate portion having a first upper surface and a first lower surface and a second substrate portion having a second upper surface and a second lower surface. A foldable portion couples the first substrate portion to the second substrate portion and comprises a flexible material attached to the first and second lower surfaces. 
     A method of manufacturing a foldable substrate includes providing a wafer having a body portion, an upper surface and a lower surface and providing one or more devices on the upper surface of the wafer. Each device comprises at least one zone free of circuitry extending in a direction from the upper surface down through the body portion. A flexible material is attached to the lower surface of the wafer at least under each device and each circuitry-free zone is removed from the top surface of the wafer through the wafer body portion and down to, but not removing, the flexible material. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Embodiments of the present invention may be better understood by referring to the following description in conjunction with the accompanying drawings in which: 
         FIGS. 1A and 1B  are schematic representations of devices on a wafer and a close-up of one of the devices, respectively; 
         FIG. 2  is a method in accordance with an embodiment of the present invention; 
         FIGS. 3A-3E  are schematic representations of the stages of the manufacturing of a device in accordance with an embodiment of the present invention; 
         FIG. 4  is a schematic top view of the device of  FIGS. 3A-3E ; 
         FIGS. 5A-5C  are schematic representations of the stages of manufacturing a magnetic field sensor assembly incorporating the magnetic field sensor of  FIGS. 3A-3E ; 
         FIG. 6  is a perspective view of an assembled magnetic field sensor assembly of  FIGS. 3A-3E ; 
         FIGS. 7A-7E  are schematic representations of the stages of the manufacturing of a device in accordance with an embodiment of the present invention; 
         FIG. 8  is a schematic top view of the device of  FIGS. 7A-7E ; 
         FIGS. 9A-9D  are schematic representations of manufacturing a magnetic field sensor assembly incorporating the magnetic field sensor of  FIGS. 7A-7C ; 
         FIG. 10  is a perspective view of an assembled magnetic field sensor assembly of  FIGS. 7A-7E ; 
         FIGS. 11A and 11B  are, respectively, schematic top views of the embodiments shown in  FIGS. 3A-3E  and  FIGS. 7A-7E ; 
         FIGS. 12A and 12B  are schematic representations of a variation of the embodiment of the present invention shown in  FIGS. 5A-5C ; 
         FIG. 13  is a schematic representation of another embodiment of the present invention providing sensor out of plane orientation; 
         FIGS. 14A and 14   b  are schematic representations of the embodiment of the present invention shown in  FIG. 13  attached to a substrate; 
         FIGS. 15A and 15B  are schematic representations of a variation of the embodiment of the present invention shown in  FIGS. 3D and 3E  including inter-silicon vias; 
         FIG. 16  is a schematic representation of the device of  FIG. 15B  installed in an assembly; 
         FIGS. 17A and 17B  are schematic representations of a variation of the embodiment of the present invention shown in  FIGS. 7D and 7E  including inter-silicon vias; 
         FIG. 18  is a schematic representation of the device of  FIG. 17B  installed in an assembly; 
         FIG. 19  is a perspective view of the assembly of  FIG. 18 ; 
         FIGS. 20A and 20B  are schematic representations of devices, in accordance with another embodiment of the present invention, on a wafer and a close-up of one of the devices, respectively; 
         FIG. 21  is a method in accordance with another embodiment of the present invention; 
         FIGS. 22A-22C  are schematic side-views of a device in accordance with an embodiment of the present invention; 
         FIG. 23  is a schematic representation of the device of  FIGS. 22A-22C  installed in an assembly. 
         FIGS. 24A-24C  are schematic sideviews of a device in accordance with an embodiment of the present invention; 
         FIG. 25  is a schematic representation of the device of  FIGS. 24A-24C  in a right angle configuration; 
         FIG. 26  is a schematic representation of an embodiment of the present invention; and 
         FIG. 27  is a schematic representation of the device of  FIG. 26  in a right angle configuration. 
     
    
    
     It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components may be included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present invention. It will be understood by those of ordinary skill in the art that these embodiments of the present invention may be practiced without some of these specific details. In other instances, well-known methods, procedures, components and structures may not have been described in detail so as not to obscure the embodiments of the present invention. 
     Embodiments of the present invention include a magnetic field sensor based on anisotropic magnetoresistive (AMR) technology. As known, in an AMR device, thin film permalloy material is deposited on a silicon wafer while a strong magnetic field is applied to create permalloy resistors. The magnetic domains of these permalloy resistors are aligned in the same direction as the applied field thereby establishing a magnetization vector. Subsequent lithographic and etching steps define the geometry of the AMR resistors. 
     Prior to explaining at least one embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. Further, the present invention is not limited to magnetic sensors or any other specific type of device. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. 
     Generally, as is known to one of ordinary skill in the art, a wafer  102 , as shown in  FIG. 1A , is used as the basis on which a plurality of devices, e.g., magnetic field sensors  104 - n , are provided. Usually, the wafer  102  is made from a semiconductor material, e.g., silicon, although the embodiments of the present invention are not limited thereto and other base materials may be used as is well known to those of ordinary skill in the art. As will be discussed in more detail below, in one embodiment of the present invention, each magnetic field sensor  104  includes a first portion  106  and a second portion  108 . 
     Referring now to  FIG. 1B , the first portion  106  may contain an X-axis magnetometer  110  and a Y-axis magnetometer  112  oriented with respect to each other in order to detect a magnetic field along a respective X, Y axis. The second portion  108  includes a Z-axis magnetometer  114 . The Z-axis magnetometer  114  is oriented on the second portion  108  such that when the second portion  108  is oriented perpendicular to the first portion  106  along a virtual hinge  116 , the magnetometer  104 - n  is then capable of detecting a magnetic field in all three axis X,Y,Z. 
     As an overview, a method  200 , as shown in  FIG. 2 , starts at step  204  where the circuit components necessary to support a magnetometer or magnetic field sensor, for example, based on AMR technology, are built up on the wafer  102 . As known to those of ordinary skill in the art, depending upon the size of the wafer  102  a plurality of such devices  104  may be provided. Well known processes such as lithography and thin film permalloy material deposition may be used to manufacture these devices. Subsequently, step  208 , signal paths from the first portion  106  to the second portion  108  are coupled together by a hinging area or section, which will be described in more detail below, that may be created by using wafer redistribution layer (RDL) technology. 
     One of ordinary skill in the art will understand that RDL technology is usually used when referring to moving a wire bond pad. In the present invention, however, while bond pads are not necessarily being moved, the same RDL technology can be leveraged to couple the first and second portions. 
     As will be described in more detail below in one embodiment of a magnetic field sensor, each device  104 - n  is provided with a hinging area by having a portion of the wafer  102 , and other material, removed from underneath, step  212 . As part of a final process, the device  104 - n  is mounted such that the first portion  106  and the second portion  108  are orthogonal, i.e., perpendicular to one another, in order to establish the magnetic X, Y, Z axes orientation, step  216 . Of course, it should be noted that the first and second portions need not necessarily be orthogonal to one another and any angle can be provided. 
     Thus, a substrate is manufactured from a single planar material and provided with the bridging or hinging area in order to allow for two portions to subsequently be arranged at a desired angle with respect to one another. The manufactured device is, therefore, bendable. 
     A wafer  102  having a lower surface  302  and an upper surface  304 , as shown in  FIG. 3A , is processed in accordance with known wafer processing techniques to create the circuitry necessary for creating a magnetic field sensor including first, second and third connection pads  305 ,  306  and  307 , respectively, placed on the upper surface  302 . These connection pads  305 ,  306  and  307  may be made from any one of a number of conductive metals, for example, copper, gold, silver, etc. Subsequently, a passivation layer  308  is deposited on the upper surface  304 , as shown in  FIG. 3B . The passivation layer  308 , however, is configured such that a substantial portion of the connection pads  305 ,  306  and  307  are left exposed. Next, a lower insulating layer  310  is deposited over the passivation layer  308  but, similar to the deposition of the passivation layer  308 , the connection pads  305 ,  306  and  307  are left exposed. It should be noted that there are a number of known techniques for assuring that any deposited layer does not cover any particular area. These processes include photo masking or etching, for example. 
     A coupling strip  312  is then provided which connects the connection pad  305  and the connection pad  306  to one another. Thus, these two connection pads  305 ,  306  are electrically coupled to one another by the coupling strip  312 , as shown in  FIG. 3C . 
     An upper insulating layer  314  is then deposited over the exposed portions of the lower insulating layer  310 , and the coupling strip  312 , as shown in  FIG. 3D . The upper insulating layer  314 , however, is configured such that it does not cover the third connection pad  307  which is, instead, left, effectively, exposed. 
     Once the wafer processing is completed, i.e., all of the layers or strips have been deposited to complete the manufacturing of the devices, and the wafer  102  has been through any other process steps, the devices  104 - n  must be cut away from the wafer  102  itself. In accordance with one embodiment of the present invention, however, prior to the individual device  104 - n  being cut from the wafer  102 , a portion of each device  104 - n  is cut away to create a gap  320 , as shown in  FIG. 3E . 
     The gap  320  is located in that portion of the wafer  102  below, or corresponding to, the coupling strip  312  between the first connection pad  305  and the second connection pad  306 . The gap  320  may be created in the wafer  102  for each device  104 - n  either by blade sawing, laser sawing or by an etching operation with appropriate masking. In any event, the wafer  102  is cut from the back surface  302  through the wafer  102  and through the passivation layer  308  leaving the lower insulating layer  310 , the coupling strip  312  and the upper insulating layer  314  untouched. In addition, even the lower insulating layer  310 , or a portion thereof, may be removed to create the gap  320 . As a result, each device  104 - n , as described above, has the first portion  106  coupled to the second portion  108  by a remaining part of the lower insulating layer  310 , the coupling strip  312  and the upper insulating layer  314  to define a foldable bridge portion  324 . The coupling strip  312  electrically couples, in this case, the first connection pad  305  to the second connection pad  306 . Thus, any circuitry coupled to these respective connection pads are coupled through this coupling strip  312 . 
     It should be noted that  FIGS. 3A-3E  represent a side view of the device and that there may be numerous other connection pads  305 - n  and  306 - n  also coupled from the first portion  106  to the second portion  108 . Thus, referring to  FIG. 4 , a top view of a device, there is shown a number of connection pads  307 - n  similar to the third connection pad  307  that are exposed through the upper insulating layer  314  and a number of coupling strips  312 - n  below the upper insulating layer coupling connection pads  305 - n  on the first portion  106  to other connection pads  306 - n  on the second portion  108  across the gap  320 . Thus, one of ordinary skill in the art will understand that the plurality of coupling strips  312 - n  are at a same level, in the build-up of circuitry layers, with one another. 
     As the device  300  is bendable by operation of the foldable bridge portion  324 , those layers or strips in the foldable bridge portion  324  are of a thickness and/or material that facilitates being bendable without breaking. Such materials include, but are not limited to, metals, semiconductors, insulators, etc. One of ordinary skill in the art will understand that various materials, conductive and non-conductive, can be used in the foldable bridge portion  324  to provide the functionality described herein. 
     Once a device  104 - n  is separated from the wafer, it is then connected to additional circuitry, for example, an ASIC device, that will process the magnet field sensor outputs to create a magnetic field sensor assembly. Referring now to  FIG. 5A , a printed circuit board (PCB)  504  is provided and a spacer  508 , optionally, is attached to an upper surface of the PCB  504  using die attach processing  512 . A base device  516  is attached to the spacer  508  by the same die attach processing  512 . The base device  516  has a plurality of device contacts  518 - n  on its upper surface. 
     A magnetic field sensor device  104 - n  is positioned adjacent the spacer  508  and the base device  516  such that the second portion  108  of the device  104  is perpendicular to the first portion  106 . Referring to  FIG. 5B , the magnetic field sensor device  104  may be positioned by being picked, for example, by a “pick and place” device, or by a die bonder directly and placed onto the PCB  504  such that the second portion  108  is displaced when contacting the base device  516  as shown. The flexibility of the foldable bridge portion  324  allows the second portion  108  to bend with respect to the first portion  106 . 
     Subsequently, the first portion  106  and the second portion  108  are attached to the PCB  504  and/or the base device  516  by using epoxy or underfill  526 , as shown in  FIG. 5C , to maintain the orthogonality between the first portion  106  and the second portion  108 . 
     Bond wires  528 - n  are used to attach the connection pads  306 - n  to the base device contact pads  518 - n . Another set of bond wires  530 - n  are used to couple the contact pads  519 - n  of the base device  516  to the PCB contacts  524  of the PCB  504 . The entire device, as shown in  FIG. 6 , comprising the PCB  504 , the base device  516  and the magnetic field sensor  104  is then encapsulated and/or molded to provide a single device for subsequent integration into, for example, a cell phone. 
     Alternatively, the orthogonality of the first portion  106  to the second portion  108  may be established without the use of an ASIC device as is shown in  FIGS. 12A and 12B , for example. Here, the PCB  504  has a guide spacer  1202  attached, for example, by die attach processing  512 , to an upper surface of the PCB  512 . The device  104  is then picked and placed onto the PCB  512  such that the second portion  108  comes into contact with the guide spacer  1202  as the device  104  is being brought toward the PCB  504 . This contact with the guide spacer  1202  deflects the second portion  108  to be at a right angle to the first portion  106  due to the height of the guide spacer  1202  and its location with respect to the first portion  106 . The relationship between the first portion  106  and the second portion  108  is maintained with the die attach processing  512 , for example, epoxy, and may also include potting material after all connections are made and testing is complete. Further, similar to the embodiment described above, bond wires (not shown) may be attached as necessary. 
     One of ordinary skill in the art will understand that the guide spacer  1202  may be configured to establish any desired angle between the first and second portions and not just 90°. 
     A modification of the embodiment shown in  FIGS. 3D and 3E  will now be described with respect to  FIGS. 15A ,  15 B and  16 . Specifically, a device  1500  is generally similar to the device  300  except that each of the first, second and third connection pads  305 - 307  is coupled to first, second and third vias  1505 - 1507 , respectively. Each of the first, second and third vias  1505 - 1507  terminates with a first, second and third via pad  1515 - 1517 , respectively. The first, second and third vias  1505 - 1507  may be referred to as “through silicon vias.” As shown in  FIG. 15B , the gap  320  is created and the vias allow for access to circuitry on the first and second portions as may be necessary. One of ordinary skill in the art will understand that not all of the connection pads may have a corresponding via and, therefore, not all will necessarily be accessed. 
     Referring to  FIG. 16 , the device  1500  may be oriented on a substrate  1552  by, for example, a PCB with a guide  1554  positioned thereon. The guide  1554  may have a guide pad  1558  positioned thereon. An upper surface of the substrate  1552  may have first and second guide pads  1562 ,  1566  provided thereon. The device  1500 , when placed downward toward the substrate  1552  and in proximity to the guide  1554 , will allow for the first and second portions to be oriented at the desired angle with respect to one another. The first, second and third via pads  1515 - 1517  are configured to oppose the guide pad  1558  and first and second substrate contact pads  1562 ,  1566  and may be connected by any one of a number of methods as known, including, but not limited to, wave soldering, ball grid array, etc. Thus, an electrical contact from the circuits on the device to either the substrate  1552  or the guide  1554  may be made possible. 
     In addition, one of ordinary skill in the art will understand that either an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) may be placed between the guide  1554  and the device  1500 , along with bump processing where necessary, in order to create an electrical connection between them. 
     A second embodiment of the present invention, similar to the first embodiment described above, also begins with a wafer  102  having an upper surface  304  and a back surface  302 , as shown in  FIG. 7A . First, second and third connection pads  705 ,  706  and  707  are disposed by any one of a number of known technologies on the upper surface  304 . Subsequently, a passivation layer  708  is disposed on the upper surface  304 , however, leaving the connection pads  705 ,  706  and  707  exposed. Similarly, a lower insulating layer  710  is disposed over the passivation layer  708  but also leaving the connection pads  705 ,  706  and  707  exposed. 
     A coupling strip  712  is disposed over a portion of the lower insulating layer  710  so as to electrically couple the second connection pad  706  to the third connection pad  707 , as shown in  FIG. 7B . 
     An upper insulating layer  714  is provided over the lower insulating layer  710  and the coupling strip  712 . The upper insulating layer  714 , however, is masked so as to leave exposed the first connection pad  705  as well as the portion of the coupling strip  712  that is coupled to the second connection pad  706 , as shown in  FIG. 7C . 
     A first conductive bump  716  is disposed in the opening in the upper insulating layer  714  corresponding to the first connection pad  705  as shown in  FIG. 7D . A second conductive bump  717  is provided in the upper insulating layer  714  to couple with the exposed portion of the coupling strip  712  corresponding to the second connection pad  706 . 
     A first solderable portion  718  is coupled to the first conductive bump  716  and a second solderable portion  719  is coupled to the second conductive bump  717 , as shown in  FIG. 7E . Similar to the description above with respect to removing a device from the wafer  102 , a gap  720  is cut through the wafer  102 , in one example, accessed through the back surface  302 , through the wafer body  102  and the passivation layer  708 , as shown in  FIG. 7E . Thus, the insulating layer  710 , the coupling strip  712  and the upper insulating layer  714  create a foldable bridge portion  801  between a first portion  802  and a second portion  803 . 
     As the device  700  is bendable by operation of the foldable bridge portion  801 , those layers or strips in the foldable bridge portion  801  are of a thickness and/or material that facilitates being bendable without breaking. Such materials include, but are not limited to, metals, semiconductors, insulators, etc. One of ordinary skill in the art will understand that various materials, conductive and non-conductive, can be used in the foldable bridge portion  801  to provide the functionality described herein. As shown in  FIG. 8 , a top view of the device, one can see that the first solderable portion  718 - n  and the second solderable portion  719 - n  are accessible, i.e., extend, from the upper insulating layer  714 . The second solderable portion  719 - n  is electrically coupled to the corresponding third connection pad  707 - n . Thus, one of ordinary skill in the art will understand that the plurality of coupling strips  712 - n  are at a same level with one another. 
     The magnetic field sensor  800  now must be integrated with a base device, similar to the first embodiment described above. Thus, referring to  FIG. 9A , a PCB  904  is provided with a base device  908  attached  912  to a top surface of the PCB  904 . As above, the attachment  912  of the base device  908  to the PCB  904  may be accomplished by any one of a number of known attachment technologies. A top surface of the base device  908  includes first, second and third base device contact pads  916 ,  918  and  920 , respectively. The PCB  904  also includes at least one PCB contact pad  906 . 
     In the attachment process, the magnetic field sensor  800  is inverted and oriented such that the solderable portion  719  is aligned with the base device contact pad  916  and the solderable portion  718  is aligned with the second base device contact pad  918 , as shown in  FIG. 9B . Once the sensor  800  is so aligned, the second portion  803  is then bent about the foldable bridge portion  801  so as to be oriented orthogonally with respect to the first portion  801 . The device  800  is then maintained in that orientation by the application of, for example, epoxy  917 . A bond wire  922  is then provided to attach the third base device contact pad  920  to the PCB contact pad  906 , as shown in  FIG. 9C . 
     Alternatively, as shown in  FIG. 9D , a first bump  930  may be placed on the first base device contact pad  916  and a second bump  934  may be placed on the second base device contact pad  918  by any of the known bump processing technologies. Either an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP)  938  may be placed between the base device  908  and the sensor  800 . One of ordinary skill in the art will understand how either ACF or ACP is provided and placed in order to accomplish the connection between the sensor  800  and the base device  908 . 
     As shown in the perspective view of the device in  FIG. 10 , a plurality of bond wires  920 - n  are provided to couple a plurality of signals from the base device  908  to the PCB  904 . Similar to the first embodiment, the assembly of the PCB  904 , the base device  908  and the attached sensor  800  is then covered with epoxy or other packaging technology in order to provide a single unitary device for subsequent insertion into a device, for example, a phone having GPS capabilities. 
     In another embodiment of the present invention, one or more metal strips are provided in order to strengthen the foldable portion. Referring now to  FIG. 11A , a device  1100 , which is similar to the device shown in  FIG. 4 , includes a plurality of metal strips  1104 - n  extending from the first portion  106  to the second portion  108 . These metal strips  1104 - n  are provided at the same level as the coupling strips  312 - n  although the metal strips  1104 - n  do not couple a circuit on the first portion  106  to a circuit on the second portion  108 . The metal strips  1104 - n  provide additional strength across the foldable bridge portion  324 . 
     Referring now to  FIG. 11B , a device  1110 , which is similar to the device shown in  FIG. 8 , includes a plurality of metal strips  1114 - n  extending from the first portion  106  to the second portion  108 . These metal strips  1114 - n  are provided at the same level as the coupling strips  712 - n  although the metal strips  1114 - n  do not couple a circuit on the first portion  802  to a circuit on the second portion  803 . The metal strips  1114 - n  provide additional strength across the foldable bridge portion  801 . 
     A modification of the embodiment shown in  FIGS. 7D and 7E  will now be described with respect to  FIGS. 17A ,  17 B and  18 . Specifically, a device  1600  is generally similar to the device  700  except that each of the first, second and third connection pads  705 - 707  is coupled to first, second and third vias  1605 - 1607 , respectively. Each of the first, second and third vias  1605 - 1607  terminates with a first, second and third via contact pad  1615 - 1617 , respectively. The first, second and third vias  1605 - 1607  may be referred to as “through silicon vias.” As shown in  FIG. 17B , the gap  720  is created and the vias allow for access to circuitry on the first and second portions as may be necessary. One of ordinary skill in the art will understand that not all of the connection pads may have a corresponding via and, therefore, not all will necessarily be accessed. 
     Referring to  FIG. 18 , the device  1600  may be oriented on the base device  908 , similar to that which has been described above. Advantageously, the first, second and third contact pads  1615 - 1617  are then “externally” available for connection. As shown in  FIG. 19 , the first, second and third via contact pads  1615 - 1617  may present multiple locations for connecting by, for example, bond wire soldering. 
     In addition, one of ordinary skill in the art will understand that either an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) may be placed between the base device  908  and the device  1600 , along with bump processing where necessary, in order to create an electrical connection between them. 
     In another embodiment of the present invention, rather than defining the device to have two portions with one gap between, three portions, with two gaps, are defined. Advantageously, in the case of a three-dimensional (3D) sensor application, the device can be bent to have two angled portions. 
     Referring now to  FIG. 13 , a device  1300  includes first, second and third portions  1304 ,  1308  and  1312  with a first gap  1316  between the first and second portions  1304 ,  1308  and a second gap  1320  between the second and third portions  1308 ,  1312 . A first foldable bridge portion  1324  extends across the first gap  1316  and a second foldable bridge portion  1328  extends across the second gap  1320 . The foldable bridge portions and gaps were created in a same manner as has been described above with the deposition of layers and strips and the removal of substrate material. 
     The device  1300  may include a sensor structure fabricated on its surface. Thus, in the case of a 3D sensor application, each portion  1304 ,  1308  and  1312  may have a respective sensor structure P, D, S fabricated on the surface. In one example, as will be discussed below, the sensors D, S on the second and third portions  1308 ,  1312 , respectively, are oriented in a first direction, represented by arrows D, S and the sensor P on the first section  1304  is oriented in a second direction represented by arrow P. 
     Referring now to  FIG. 14A , in order to obtain out of plane sensing from the device  1300 , a substrate  1404 , for example, a printed circuit board (PCB) is provided with first and second spacers  1408 ,  1412  attached, for example, by epoxy  1416  or any other known mechanism, to an upper surface of the substrate  1404 . The device  1300  is then placed on the substrate  1404  such that each of the first and third portions  1304 ,  1312  is out of plane, with respect to the second portion  1308 , at a same angle X. 
     Alternatively, referring to  FIG. 14B , rather than building the PCB  1404  to accomplish the out-of-plane configuration, bumps  1420 ,  1422  could be placed on the bottom of the first and third portions  1304 ,  1312 , respectively. The bumps  1420 ,  1422  would be sized to maintain the two portions  1304 ,  1312  at the desired angles. 
     Thus, when the first portion  1304  and the third portion  1312  are at the same tilt angle X, the respective sensors P, S would have the same out of plane sensing component. As a result, if an output of the first sensor P is S P  and an output of the third sensor S is S S , then the sum S P +S S  is an out of plane sensing signal S OP , and the difference S P −S S  is an in plane sensing signal S IP . 
     The second portion  1308  may operate as an interconnection and landing space for bond wires in order to interface with other devices in the system such as, for example, an ASIC device. Further, the sensor on the second portion  1308  may be optional but could operate as an additional in-plane sensor. 
     A pick and place machine may be used to place the device  1300  on to the substrate  1404 . As the pick and place machine pushes down the device  1300 , the first and third portions  1304 ,  1312 , will be deflected upwards by those spacers  1408 ,  1412  to form the defined angle X. This angle X can be anywhere between 0 and 90 degrees. In one embodiment, an optimum value can be chosen, for example, 30 degrees. 
     Alternatively, the device  1300  may be placed on top of a device such as an ASIC and then the ASIC attached to another substrate, for example, a PCB, as part of a final package. Bond wires can be attached as necessary for electrical interconnection or other purposes. 
     In a variation of the device  1300 , either of the first or third portions  1304 ,  1312 , can be eliminated to reduce size and cost. In such a case, the out of plane sensing signal S OP , described above, is no longer valid. An out of plane function may then be determined by comparing the output of the in-plane sensor S D  and the remaining out of plane sensor, either S P  or S S . While it is possible that a residue error of S OP  could produce a heading error in a compass, such an error may be reduced by application of an appropriate correction algorithm. 
     In another embodiment of the present invention, a multi-plane device is made from a single plane substrate, for example, a wafer, by incorporating a flexible component. 
     Generally, as is known to one of ordinary skill in the art, a wafer  102 , as shown in  FIG. 20A , is used as the basis on which a plurality of devices  1900 - n  are provided. Usually, the wafer  102  is made from a semiconductor material, e.g., silicon, although the embodiments of the present invention are not limited thereto and other base materials may be used as is well known to those of ordinary skill in the art. As will be discussed in more detail below, in this embodiment of the present invention, each device  1900 - n  includes a first portion  1904 , a second portion  1908  and a third portion  1912  with a first clear zone  1916  between the first and second portions  1904 ,  1908  and a second clear zone  1920  between the first and third portions  1904 ,  1912 . 
     Referring now to  FIG. 20B , the first, second and third portions  1904 ,  1908 ,  1912  may contain any type of circuitry or components as may be desired and positioned, or built up, by any of many known methods. It is necessary, however, that there be no circuitry or functional devices placed in any of the clear zones  1916 ,  1920 . 
     As an overview of a method of manufacturing, a method  2000 , as shown in  FIG. 21  starts at step  2004  where a plurality of devices  1900  are built up on the wafer  102 . As known to those of ordinary skill in the art, depending upon the size of the wafer  102  a plurality of such devices  1900  may be provided. Well known processes such as, for example, lithography and thin film material deposition may be used to manufacture these devices. In addition, step  2008 , each device is arranged to have at least one clear zone that separates at least two portions of the device  1900  from each other. 
     Next, step  2012 , a flexible film is attached to a bottom surface of the wafer at least under each device  1900 . Alternatively, adhesive tape or plated metal could be used in place of the flexible film. Subsequently, step  2016 , from a top surface of each device, each clear zone in the wafer is removed down to the flexible film. Once the free zones have been cut away, each individual device is cut from the wafer, step  2020 , for subsequent additional processing as necessary. 
     Referring now to  FIG. 22A , a cross-section of the device  1900 , the substrate  102  includes a flexible piece of material, for example, a film  2102  attached to a bottom surface. Merely for explanatory purposes, the first portion  1904  is shown as having two connection pads  2108 ,  2112  that have been left exposed in an upper surface. These connection pads may have been formed in a manner similar to that which has been described above. Of course, one of ordinary skill in the art will understand that there may be multiple connection pads and/or pads that are not exposed but instead covered. The second portion  1908  includes a connection pad  2104  and the third portion includes a connection pad  2116 . Each of the first and second clear zones  1916 ,  1920  is free from any components from either of the adjacent portions. 
     As described above with reference to step  2016  in method  2000 , the material in each of the free zones  1916 ,  1920  is removed down to the flexible film portion  2102 . The material of any upper deposited layer on the substrate  102  can be removed by blade sawing, laser sawing, an etching operation with appropriate masking or by any combination of the foregoing. The device  1900 , as shown in  FIG. 22B , is the result of the removal of the free zones  1916 ,  1920 . It should be noted that it is not necessary that all of the wafer material be removed as some may be left that does not interfere with the flexibility of the film portion  2102 . 
     Advantageously, the flexible portion  2102  allows the first, second and third portions  9104 ,  1908 ,  1912  to be oriented in an out-of-plane manner as shown in  FIG. 22C . Thus an out-of-plane carrier has been created from an in-plane manufacturing process. 
     As a result, an out-of-plane arrangement of the device  1900  is made possible as shown in  FIG. 23 . Here, a substrate  2202 , for example a PCB, includes a guide or support  2204  mounted on an upper surface thereof. The device  1900  is then placed, in a manner similar to that described above, on the support  2204  such that the first portion  1904  and the third portion  1912  are at a predetermined angle to one another. The device  1900  may be attached by, for example, epoxy, or any other known mechanism. It should be noted that there is no second portion in this example device  1900  although there could be, however, only two portions are shown for simplicity of explanation. The substrate  2202  may include a substrate contact pad  2212  for connection to the connection pad  2116  of the third portion  1912 . Optionally, the substrate contact pad  2116  may include a bump  2208  provided by a bump process for connecting to the substrate contact pad  2212  by a bond wire  2216 . One of ordinary skill in the art will understand that there are many known ways for providing such connections. 
     Referring now to  FIG. 24A , an embodiment of the present invention includes a device  2400 , similar in construction to the device  300  shown in  FIG. 3D , that includes an alternate version of the gap. Here, a gap is provided with angled walls rather than straight walls as shown in the foregoing embodiments thereby allowing for various positioning of one portion with respect to another portion. To create the device  2400 , initially, a first wedge gap  2404  is created in the substrate material  102 , by, for example, a V-shaped blade cut. Of course, one of ordinary skill in the art will understand that other methods or tools could be used to create the first wedge gap. The blade cut, however, is adjusted in order not to damage the passivation layer  308  underneath the lower insulating layer  310  and the coupling strip  312  along with the upper insulating layer  314  that create the foldable portion. Accordingly, the blade is set to remove material no closer than a distance W from the lower passivation layer  308 . The first wedge gap  2404  may have an initial angle V that may be chosen depending upon the material, the sharpness of the blade and any other design considerations. 
     Subsequently, as shown in  FIG. 24B , the first wedge gap  2404  is modified to create an expanded wedge gap  2406 . The expanded wedge gap  2406  may be created by, for example, etching the substrate material  102  by any one of many known lithography processes and the like. Of course, one of ordinary skill in the art will understand that other methods or tools could be used to create the expanded wedge gap. As a result, the expanded wedge gap  2406  has a “flat” portion having a width T, as shown. 
     A layer of die attach film  2408  is placed across the bottom of the substrate  102  and thus covers the expanded wedge gap  2406 , as shown in  FIG. 24C . The die attach film  2408  is flexible and does include some amount of stickiness and such die attach film may be available from, for example, Hitachi Chemical Company. 
     The provision of the expanded wedge gap  2406  and the die attach film  2408  allows for first and second portions  2412 ,  2416  to be arranged at a predetermined angle with respect to one another. Thus, the first portion  2412  can be moved with respect to the second portion  1416  by operation of the foldable portion, as described above, resulting in the configuration shown in  FIG. 25 . As shown, the expanded wedge gap  2406  is reduced by the moving of the first portion  2412  with respect to the second portion  2416 . The die attach film  2408 , being a flexible film, will tend to roll up into the wedge gap  2406 . The width T is generally about twice the thickness of the film  1408 . 
     Due to the stickiness of the die attach film  2408 , the device  2400  will be maintained in the orientation that will facilitate installation of the device  2400  in a subsequent assembly. 
     Referring now to  FIG. 26 , in another embodiment of the present invention, a device  2600  can be provided with multiple expanded wedge gaps  2406 - 1 ,  2406 - 2  as a modification of the device  1300  shown in  FIG. 13 . The die attach film  2408  allows for the device  2600  to be bent into a “U” shape as shown in  FIG. 27 . 
     It should be noted that the packaging described herein can be applied to magnetic sensors, for example, an electronic compass. Further, the packaging may be applied to accelerometer sensors, gyroscope sensors and electrical field sensors in addition to any circuitry amenable to placement on a wafer or similar planar substrate. 
     Still further, a device may have multiple foldable portions, for example, one on a top surface and another on the bottom surface to provide different configurations of the substrate. 
     Having thus described several features of at least one embodiment of the present invention, it is to be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure and are intended to be within the scope of the invention. Accordingly, the foregoing description and drawings are by way of example only, and the scope of the invention should be determined from proper construction of the appended claims, and their equivalents.