Patent Publication Number: US-7709861-B2

Title: Systems and methods for supporting a subset of multiple interface types in a semiconductor device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation in part of U.S. patent application Ser. No. 11/530,550 entitled “SYSTEMS AND METHODS FOR DISTRIBUTING I/O IN A SEMICONDUCTOR DEVICE” and filed Sep. 11, 2006 by Madhani et al.; which is now US Pat. No. 7,271,485. The aforementioned application is assigned to an entity common hereto and is incorporated herein by reference for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is related to connecting IO from a semiconductor die to a package. More particularly, the present invention is related to systems and methods for connecting one of multiple interface types implemented on a semiconductor die to appropriate pins on different packages encapsulating a substantially similar semiconductor die. 
     A typical semiconductor design provides a number of IO buffers that are carefully placed around the periphery of a semiconductor die to be in proximity to package pins to which the IO buffers will be bonded.  FIG. 1   a  shows an example of such a layout approach where a semiconductor die includes a number of IO buffers  110  surrounding the periphery of a semiconductor die  100 , with each IO buffer  110  located in proximity to respective package pins  120 . Each of IO buffers  110  include a single bond pad indicated by the cross-hatched area on the respective IO buffers  110 . Some of IO buffers  110  are electrically coupled to package pins  120  by bonding wires  130 . Other of the IO pads  110  are bonded to a ground plane  150  indicated by the lined area surrounding semiconductor die  100 , or to a power plane  160  indicated by the stippled area surrounding semiconductor die  100 . The different IO buffers are coupled to electrical circuitry on semiconductor die  100  that implement different interface types. In particular, IO buffer  110   b  and IO buffer  110   c  are electrically coupled to a circuit implementing an interface A. IO buffer  110   d  and IO buffer  110   e  are electrically coupled to a circuit implementing an interface B. IO buffer  110   h , IO buffer  110   i , IO buffer  110   j , IO buffer  110   k  and IO buffer  110   l  are electrically coupled to a circuit implementing an interface C. IO buffer  110   o , IO buffer  110   p , IO buffer  110   q , IO buffer  110   r  and IO buffer  110   u  are electrically coupled to a circuit implementing an interface D. IO buffer  110   v  and IO buffer  110   w  are electrically coupled to a circuit implementing an interface E; and IO buffer  110   x  and IO buffer  110   y  are electrically coupled to a circuit implementing an interface F. 
     Turning to  FIG. 1   b , one conventional circuit  199  for connecting an IO buffer to associated interface circuitry is depicted. Circuit  199  may be implemented for each of IO buffers  110  shown in  FIG. 1   a . Circuit  199  includes a semiconductor substrate  177  with a number of metal layers  162 ,  184 ,  188 ,  192 ,  196  disposed thereon. It should be noted that the aforementioned metal layers may be formed of a conductive metal or other conductive materials as are known in the art. Thus, as used herein, the phrase “metal layer” is understood to mean a layer of conductive material. Each of metal layers  162 ,  184 ,  188 ,  192 ,  196  is separated from adjacent metal layers and semiconductor substrate  177  by insulating layers  164 ,  182 ,  186 ,  190 ,  194 ,  198 . In addition, IO buffer  110  includes a bond pad  112 . Bond pad  112  includes two bond pad layers  170 ,  171  interconnected by a number of vias  172 . Bond pad  112  is further connected to underlying circuitry by way of a via  175 . As shown, via  175  electrically couples bond pad  112  to a wire on metal layer  184 , but could connect bond pad  112  to lower metal layers where such was desired. 
     In an ideal situation, bond wires  130  are as short as possible and extend directly to an adjacent package pin without crossing another bond wire or requiring any substantial directional changes. To accommodate this ideal situation, semiconductor die  100  of  FIG. 1   a  may be designed such that IO buffers are located at the ideal locations such that they are aligned with respective package pins. Thus, a semiconductor die is often designed with some consideration of the final interfaces that will be supported and into which package the semiconductor die will be encapsulated. For most designs, such an approach is possible, however, it can be costly. In particular, while all interfaces are offered, the device may result in higher than necessary part costs and at times an uncompetitive price point for a given part. In addition, such an approach may result in inordinately high pin count packages that are not compatible with particular end designs or form factors. 
     Other approaches to reduce interfaces offered and thereby reduce pin count include implementing various versions of the semiconductor design that each contemplate a particular IO set and package. Such an approach, however, is costly as it requires the maintenance of different designs, the production of different semiconductor die, and in some cases a reduction of overall yield. Again, the aforementioned limitations may combine to render a device uncompetitive. 
     Another option is to implement a custom package design, or force a given semiconductor design into selected package that is not optimized for the semiconductor die. Neither option is ideal as a custom package design may introduce yield problems, and in any event may be costly. Turning to  FIG. 1   c , an example of forcing a particular die into a selected package is depicted. Semiconductor die  100  may be packaged in a package including fewer package pins compared with that shown in  FIG. 1   a . In such a case, the reduced number of package pins may reduce the number of interfaces that are implemented. Thus, as shown, only interface B, interface D, interface E and interface F are provided at the package pins. In using a different package, it may be necessary to use long bond wires  130  to extend from IO buffers associated with the desired interface circuitry and the selected package pins. While such an approach may be possible in some circumstances, it may not be ideal as the length of the bond wires is increased. Further, in some cases, such an approach may not be possible due to the length of bond wires and/or cross over between the bond wires with the potential of electrical shorts associated therewith. 
     Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for providing flexibility in packaging a semiconductor die and/or implementing the semiconductor die. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is related to connecting IO from a semiconductor die to a package. More particularly, the present invention is related to systems and methods for connecting one of multiple interface types implemented on a semiconductor die to appropriate pins on different packages encapsulating a substantially similar semiconductor die. 
     Various embodiments of the present invention provide systems and methods for implementing multi-mode semiconductor devices. In particular, one embodiment of the present invention provides a multi-mode semiconductor device that includes a device package with at least one package pin. In addition, the device includes a semiconductor die with at least two IO buffers. An IO buffer located near the package pin includes a first bond pad and a floating bond pad. The first bond pad is electrically coupled to a circuit implementing a first interface type. The other IO buffer includes a second bond pad that is electrically coupled to a circuit implementing a second interface type. In some cases, the floating bond pad is electrically coupled to the circuit implementing the second interface type by a conductive interconnect, and to the package pin. In some cases, the conductive interconnect is on a conductive or metal layer at a level coincident with the first floating bond pad. In one particular case, the conductive layer is an aluminum layer and the floating bond pad is formed of aluminum. 
     The two different interface types may be, but are not limited to, a USB interface, a 1394 interface, and an ATA interface. In one particular case, the first bond pad is electrically coupled to the circuit implementing the first interface type by way of a first via extending below the first bond pad; and the second bond pad is electrically coupled to the circuit implementing the second interface type by way of a second via extending below the second bond pad. In such a case, the second bond pad may be implemented in aluminum, and the via may connect the second bond pad to a copper conductive layer. 
     Other embodiments of the present invention provide configurable IO semiconductor devices. Such devices include two or more IO buffers. At least one of the IO buffers includes two bond pads, with one of the bond pads being associated with a first interface type. In some cases, the other bond pad not associated with the first interface type is a floating bond pad. Each of the aforementioned bond pads is selectably bondable to an external IO. Where one of the bond pads is bonded to the external IO, the external IO is configured to support the first interface type. In contrast, where the other of the bond pads is bonded to the external IO, the external IO is configured to support the second interface type. In some cases, the external IO is a package pin. In some such cases, the package pin is included in a package that encases a semiconductor substrate on which the IO buffers are implemented. In such cases, fewer than all of the interfaces offered at the semiconductor substrate level may be connected external to the package. In some cases, the bond pad of the other IO buffer is electrically coupled to the second interface type via a conductive interconnect disposed at a level substantially coincident with the second bond pad. In some instances, the conductive interconnect is formed of aluminum. 
     Yet other embodiments of the present invention provide multiple IO mode semiconductor devices. Such semiconductor devices include a device package with at least one package pin, and a semiconductor die. The semiconductor die includes a first IO buffer located a first distance from the package pin and a second IO buffer located a second distance from the package pin. The first IO buffer includes a first bond pad and a floating bond pad. The first bond pad is electrically coupled to a first circuit implementing a first interface type. The second IO buffer includes a second bond pad electrically coupled to a second circuit implementing a second interface type. In some instances of the aforementioned embodiments, at least one of the first bond pad and the floating bond pad is implemented using CUP technology. In various instances of the aforementioned embodiments, the first bond pad is electrically coupled to the first circuit by a first via, and the second bond pad is electrically coupled to the second circuit by a second via. In one or more instances of the aforementioned embodiments, the floating bond pad is electrically coupled to the second circuit via a conductive interconnect, and to the package pin. In various instances, the conductive interconnect is disposed on a conductive layer at a level substantially coincident with the floating bond pad. In particular cases, the conductive interconnect is formed of aluminum. 
     Yet further embodiments of the present invention provide methods for manufacturing a multi-mode semiconductor device. Such methods include providing a semiconductor die that includes a first IO buffer and a second IO buffer. The first IO buffer includes a first bond pad and a second bond pad. The first bond pad is electrically coupled to a first circuit implementing a first interface type. The second IO buffer includes a third bond pad electrically coupled to a second circuit implementing a second interface type. The methods further include providing a package that includes a package pin, and placing a bind wire electrically coupling the second bond pad to the package pin. In addition, the methods further include forming a conductive interconnect that electrically couples the second bond pad to the third bond pad. Thereby the second bond pad is electrically coupled to the second circuit via the third bond pad. Forming the conductive interconnect may be done using any of a number of processes known in the art including, but not limited to, conductive material deposition; a combination of conductive material deposition and etch; forming a trench in the semiconductor die and filling the trench with a conductive material; or forming a trench in the semiconductor die, filling the trench with a conductive material, and removing a portion of the conductive material by chemical, mechanical polishing. 
     Additional embodiments of the present invention provide multiple die semiconductor devices. Such multiple die semiconductor devices include a device package with at least two package pins. The devices further include two or more semiconductor die with each of the semiconductor die including a number of IO buffers. One of the IO buffers is located at a position that is relatively difficult to access when compared with another of the IO buffers. In this case, one of the pads on each of the IOP buffers may be electrically coupled, and the more easily accessed IO pad may be bonded to one of the package pins. 
     This summary provides only a general outline of some embodiments according to the present invention. Many other objects, features, advantages and other embodiments of the present invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A further understanding of the various embodiments of the present invention may be realized by reference to the figures which are described in remaining portions of the specification. In the figures, like reference numerals are used throughout several drawings to refer to similar components. In some instances, a sub-label consisting of a lower case letter is associated with a reference numeral to denote one of multiple similar components. When reference is made to a reference numeral without specification to an existing sub-label, it is intended to refer to all such multiple similar components. 
         FIG. 1  depict a prior art approach to implementing a semiconductor device including multiple IO interfaces; 
         FIG. 2   a  depicts package pins in relation to a semiconductor die or substrate that includes multiple IO interfaces and multiple bond pads per IO buffer in accordance with various embodiments of the present invention; 
         FIG. 2   b  depicts a subset of the package pins of  FIG. 2   b  electrically coupled to the semiconductor die of  FIG. 2   b  such that only a subset of the multiple IO interfaces are made available via the subset of the package pins in accordance with some embodiments of the present invention; 
         FIG. 3  depicts package pins in relation to a semiconductor die or substrate that includes multiple IO interfaces and multiple bond pads per IO buffer with the bond pads staggered in accordance with other embodiments of the present invention; 
         FIG. 4  is a cross sectional view of a semiconductor device including multiple bond pads per IO buffer where one of the multiple bond pads is a floating pad in accordance with various embodiments of the present invention; 
         FIG. 5  is a flow diagram showing a process for manufacturing and packaging a multi-mode semiconductor device in accordance with one or more embodiments of the present invention; 
         FIG. 6  shows an example of using the re-routing systems and methods depicted in  FIGS. 2-5  to facilitate wafer probe testing; and 
         FIGS. 7   a - 7   b  show two exemplary implementations of multi-die devices utilizing re-routing possibilities to provide for package pin bonding in accordance with various embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is related to connecting IO from a semiconductor die to a package. More particularly, the present invention is related to systems and methods for connecting one of multiple interface types implemented on a semiconductor die to appropriate pins on different packages encapsulating a substantially similar semiconductor die. 
     Various embodiments of the present invention provide multiple bond pads associated with each IO buffer of the design and a wire formed on a conductive layer that is used to interconnect select ones of the bond pads to each other to effectively move an IO buffer to a location nearer a package pin to which the IO buffer is to be bonded. This approach allows for the reuse of a substantially similar semiconductor die design to applications requiring different packages and/or IO configurations. Thus, for example, in an integrated circuit design destined for a variety of consumer products, the basic design can be reused by forming a conductive interconnect layer that allows the semiconductor die to be implemented in a customer selected package with a customer selected IO configurations with only a minimal modification to a standard semiconductor die. As used herein, the phrase “conductive interconnect” is used in its broadest sense to mean any materially formed in such a way as to electrically connect two end points. Thus, for example, a conductive interconnect may be a metal via or metal wire extending between two endpoints. Based on the disclosure provided herein, one of ordinary skill in the art will recognize a myriad of conductive materials that may be used and methods for forming the conductive material that may be used in accordance with various embodiments of the present invention for forming a conductive interconnect. 
     As an example, the same standard semiconductor die may be used in a system on a chip design incorporating a read channel, memory and logic may be utilized for multiple form factor hard drives (e.g., one inch form factor drives, 1.8 inch form factor drives and 2.5 inch form factor drives) and/or hybrid devices (e.g., memory plus hard drive devices) each of which may require varying IO interfaces to the host system. Each of the designs could be implemented to include a different IO configuration including, but not limited to, one or more of a USB, 1394, ATA or SATA interface. Thus, rather than develop separate designs for the aforementioned system on a chip and/or package for each form factor, a single semiconductor die may be manufactured, and different lots of the standard semiconductor design can be tooled by a post manufacturing metal etch or other wire formation process that allows for tailoring the design to a particular requirement. 
     Various embodiments of the present invention provide systems and methods for implementing multi-mode semiconductor devices. In particular, one embodiment of the present invention provides a multi-mode semiconductor device that includes a device package with a number of package pins. Such a device package may be any device package known in the art including, but not limited to ball grid array packages, single-in-line packages, plastic leaded chip carrier packages and/or the like. Based on the disclosure provided herein, one of ordinary skill in the art will recognize a variety of package types with which embodiments of the present invention may be utilized. 
     The aforementioned semiconductor device includes a semiconductor die with a number of IO buffers. As used herein, the phrase “IO buffer” is used in its broadest sense to mean any location or device on a semiconductor die that is tailored for handing IO. Also, as used herein, the term “IO” is used in its broadest sense to mean any input and/or output transferring information between the semiconductor die and a package pin. As used herein, the phrase “semiconductor die” is used in its broadest sense to mean any die on which an integrated circuit is formed. Thus, for example, a semiconductor die may include, but is not limited to, a semiconductor substrate in which various circuits are formed along with various metal traces formed thereon to connect the various circuits. 
     One or more of the IO buffers include two or more bond pads. As used herein, the phrase “bond pad” is used in its broadest sense to mean any structure to which a bond wire may be attached. Thus, for example, a bond pad may be, but is not limited to, a metal area disposed above the semiconductor die. In some cases, one or more of the bond pads may be a floating pad. As used herein, the phrase “floating pad” is used in its broadest sense to mean any bond pad composed of an electrically conductive structure that is disposed over electrically conductive circuitry and/or wiring used to implement functionality unrelated to that served by the bond pad. Also, as used herein, the phrase “floating bond pad” is used in their broadest sense to mean any floating pad that is capable of attachment to a bond wire. In some instances, connection to one of the bond pads on the IO buffer is accomplished through use of a conductive layer at a level coincident with the utilized bond pad. As used herein, the phrase “level coincident with the bond pad” is used in its broadest sense to mean at least a portion is at substantially the same level above an underlying semiconductor substrate. Thus, for example, implementing on a level coincident with the bond pad may include, but is not limited to, implementing atop the same insulating layer. Where a pad is a floating pad, connecting using a metal layer at a level coincident with the bond pad may involve a metal connecting either at the top or bottom of the bond pad. Thus, based on this description, one of ordinary skill in the art will recognize that there may be some leeway between a position above a top layer of a particular bond pad and below a bottom layer of the particular bond pad that would all be considered at a level coincident with the particular bond pad. In one particular case, the metal layer used to form the connection to the particular bond pad is the same metal layer used at least in part to form the bond pad itself. 
     In some cases, one of the bond pads associated with the IO buffer is electrically coupled to a circuit implementing one interface type, and the other bond pad is electrically coupled to a circuit implementing another interface type. Selection of one or the other of the two bond pads to wire bond to the package pin in proximity to the IO buffer selects the interface to be supported by the particular package pin. As used herein, the phrase “electrically coupled” is used in its broadest sense to mean any coupling whereby an electrical signal may be passed from one end point to another end point either directly or indirectly. Thus, for example, two nodes may be electrically coupled via a conductive wire in which case they would be directly coupled. In contrast, two nodes may be coupled by way of one or more circuit elements in which case they would be indirectly coupled. 
     In some cases, one or both of the aforementioned bond pads are implemented using CUP technology. As used herein, the phrase “CUP technology” is used in its broadest sense to mean any technology where circuitry is disposed under a pad. One of various examples of such CUP technology is discussed in U.S. Pat. No. 5,751,065 issued May 1998. 
     Various embodiments of the present invention provide a mechanism for accessing a relatively difficult IO buffer in a multi-die configuration. For example, device may include two or more semiconductor die arranged such that one or more IO buffers on a respective die are in an access location that makes the IO buffer(s) difficult to access. As used herein, the phrase “access location” is used in its broadest sense to mean a location on a semiconductor die where the ease of accessing an IO buffer is affected by the location. The ease of access may be ease in relation to, for example, bonding from the IO buffer to a surrounding package pin, or ease of accessing the IO buffer for a wafer probe test. Where an IO buffer is located in an access location that is difficult to access in comparison the access location of another IO buffer, the difficult IO buffer may be electrically coupled to the relatively easy IO buffer and access to the difficult IO buffer may be had through the relatively easy IO buffer. 
     Turning to  FIG. 2   a , a semiconductor die  200  is depicted in relation to a number of package pins  120 . Semiconductor die  200  includes a number of IO buffers  220  that are bonded using bond wires  240  to a ground plane  250  indicated by the lined area surrounding semiconductor die  200 , or to a power plane  260  indicated by the stippled area surrounding semiconductor die  200 . In particular, IO buffer  220   a , IO buffer  220   c , IO buffer  220   e  and IO buffer  220   g  are bonded to ground plane  250 ; and IO buffer  220   b , IO buffer  220   d , IO buffer  220   f  and IO buffer  220   h  are bonded to power plane  260 . Each of the aforementioned IO buffers includes only a single bond pad indicated by a cross hatched region on the respective IO buffer. 
     Other IO buffers  210  are disposed in proximity to package pins  120 . In particular, IO buffer  210   a  is disposed in proximity to package pin  120   o ; IO buffer  210   b  is disposed in proximity to package pin  120   p ; IO buffer  210   c  is disposed in proximity to package pin  120   q ; IO buffer  210   d  is disposed in proximity to package pin  120   r ; IO buffer  210   e  is disposed in proximity to package pin  120   a ; IO buffer  210   f  is disposed in proximity to package pin  120   b ; IO buffer  210   g  is disposed in proximity to package pin  120   c ; IO buffer  210   h  is disposed in proximity to package pin  120   d ; IO buffer  210   i  is disposed in proximity to package pin  120   e ; IO buffer  210   j  is disposed in proximity to package pin  120   f ; IO buffer  210   k  is disposed in proximity to package pin  120   g ; IO buffer  210   l  is disposed in proximity to package pin  120   h ; IO buffer  210   m  is disposed in proximity to package pin  120   i ; IO buffer  210   n  is disposed in proximity to package pin  120   j ; IO buffer  210   o  is disposed in proximity to package pin  120   k ; IO buffer  210   p  is disposed in proximity to package pin  120   l ; IO buffer  210   q  is disposed in proximity to package pin  120   m ; and IO buffer  210   r  is disposed in proximity to package pin  120   n . Each of the aforementioned IO buffers includes an inner bond pad  212  shown as a cross hatched area located on the core side of the respective IO buffer  210 , and an outer bond pad  211  shown as another cross hatched area located on the package pin side of the respective IO buffer  210 . As more fully described below, providing multiple bond pads  211 ,  212  on the same IO buffer allows for use of the IO buffer to connect different circuits implemented on semiconductor die  200  to a particular package pin located near the respective IO buffer  210 . 
     Semiconductor die implements a number of IO interfaces. The IO interfaces are electrically coupled to respective sets of IO buffers via outer bond pads  211 . Outer bond pads  211  are electrically connected to the IO interface circuitry by way of a via extending substantially vertically below the respective bond pads  211 . In particular, semiconductor die  200  implements an interface A, an interface B, an interface C, an interface D, an interface E and an interface F. IO buffer  210   a  and IO buffer  210   b  are coupled to circuitry implementing interface A by way of a via extending between the outer bond pads of the respective IO buffers and the circuitry. IO buffer  210   c  and IO buffer  210   d  are coupled to circuitry implementing interface B by way of a via extending between the outer bond pads of the respective IO buffers and the circuitry. IO buffer  210   e , IO buffer  210   f , IO buffer  210   g , IO buffer  210   h  and IO buffer  210   i  are coupled to circuitry implementing interface C by way of a via extending between the outer bond pads of the respective IO buffers and the circuitry. IO buffer  210   j , IO buffer  210   k , IO buffer  210   l , IO buffer  210   m  and IO buffer  210   n  are coupled to circuitry implementing interface D by way of a via extending between the outer bond pads of the respective IO buffers and the circuitry. IO buffer  210   o  and IO buffer  210   p  are coupled to circuitry implementing interface E by way of a via extending between the outer bond pads of the respective IO buffers and the circuitry. IO buffer  210   q  and IO buffer  210   r  are coupled to circuitry implementing interface F by way of a via extending between the outer bond pads of the respective IO buffers and the circuitry. 
     In the case where all of the aforementioned interfaces are to be available at package pins  120 , a bond wire (not shown) would be connected between each of the outer bond pads and the package pin  120  that is closest to the IO buffer  210  that is associated with the particular package pin. However, where only a subset of package pins  120  exist and only a subset of the interfaces are to be made available at the package pins  120 , inner bond pads  212  can be used to facilitate optimal bonding to the available package pins. Turning to  FIG. 2   b , an example of optimal bonding is depicted where only a subset of package pins  120  are available, and where only interface B, interface D, interface E and interface F are to be available at the package pins. More specifically, only package pin  120   a , package pin  120   b , package pin  120   c , package pin  120   d , package pin  120   e , package pin  120   k , package pin  120   l , package pin  120   o , package pin  120   p , package pin  120   q , and package pin  120   r  are available. 
     In this case, the inner pad of IO buffer  210   a  is electrically coupled to the inner pad of IO buffer  210   r  by a conductive interconnect  231   g , and the inner pad of IO buffer  210   r  is electrically coupled to the circuitry implementing interface F by way of a via extending to a metal layer at a level below conductive interconnect  231   g  (or by connection to the outer pad of IO buffer  210   r ). In some cases, conductive interconnects  231  are implemented in a single metal layer, while in other cases they are implemented using multiple metal levels with vias extending between the multiple metal layers. A bond wire  232   a  is then installed between the inner pad of IO buffer  210   a  and package pin  120   o . Similarly, the inner pad of IO buffer  210   b  is electrically coupled to the inner pad of IO buffer  210   q  by a conductive interconnect  231   f , and the inner pad of IO buffer  210   q  is electrically coupled to the circuitry implementing interface F by way of a via extending to a metal layer at a level below conductive interconnect  231   f  (or by connection to the outer pad of IO buffer  210   q ). A bond wire  232   b  is then installed between the inner pad of IO buffer  210   b  and package pin  120   p . In this way, circuitry (i.e., the circuitry of interface F) that is as a default supported by IO buffer  210   r  and IO buffer  210   q  becomes supported by IO buffer  210   a  and IO buffer  210   b ; and circuitry (i.e., the circuitry of interface A) that is as a default supported by IO buffer  210   a  and IO buffer  210   b  is effectively disconnected. 
     The inner pad of IO buffer  210   e  is electrically coupled to the inner pad of IO buffer  210   n  by a conductive interconnect  231   e , and the inner pad of IO buffer  210   n  is electrically coupled to the circuitry implementing interface D by way of a via extending to a metal layer at a level below conductive interconnect  231   e  (or by connection to the outpour pad of IO buffer  210   n ). A bond wire  232   e  is then installed between the inner pad of IO buffer  210   e  and package pin  120   a . Similarly, the inner pad of IO buffer  210   f  is electrically coupled to the inner pad of IO buffer  210   m  by a conductive interconnect  231   d , and the inner pad of IO buffer  210   m  is electrically coupled to the circuitry implementing interface D by way of a via extending to a metal layer at a level below conductive interconnect  231   d  (or by connection to the outer pad of IO buffer  210   m ). A bond wire  232   f  is then installed between the inner pad of IO buffer  210   f  and package pin  120   b . The inner pad of IO buffer  210   g  is electrically coupled to the inner pad of IO buffer  210   l  by a conductive interconnect  231   c , and the inner pad of IO buffer  210   l  is electrically coupled to the circuitry implementing interface D by way of a via extending to a metal layer at a level below conductive interconnect  231   c  (or by connection to the outer pad of IO buffer  210   l ). A bond wire  232   g  is then installed between the inner pad of IO buffer  210   g  and package pin  120   c . The inner pad of IO buffer  210   h  is electrically coupled to the inner pad of IO buffer  210   k  by a conductive interconnect  231   b , and the inner pad of IO buffer  210   k  is electrically coupled to the circuitry implementing interface D by way of a via extending to a metal layer at a level below conductive interconnect  231   b  (or by connection to the outer pad of IO buffer  210   k ). A bond wire  232   h  is then installed between the inner pad of IO buffer  210   h  and package pin  120   d . The inner pad of IO buffer  210   i  is electrically coupled to the inner pad of IO buffer  210   j  by a conductive interconnect  231   a , and the inner pad of IO buffer  210   j  is electrically coupled to the circuitry implementing interface D by way of a via extending to a metal layer at a level below conductive interconnect  231   a  (or by connection to the outer pad of IO buffer  210   j ). A bond wire  232   i  is then installed between the inner pad of IO buffer  210   i  and package pin  120   e . In this way, circuitry (i.e., the circuitry of interface D) that is as a default supported by IO buffer  210   j , IO buffer  210   k , IO buffer  210   l , IO buffer  210   m  and IO buffer  210   n  becomes supported by IO buffer  210   e , IO buffer  210   f , IO buffer  210   g , IO buffer  210   h  and IO buffer  210   i ; and circuitry (i.e., the circuitry of interface C) that is as a default supported by IO buffer  210   e , IO buffer  210   f , IO buffer  210   g , IO buffer  210   h  and IO buffer  210   i  is effectively disconnected. 
     Interface B is connected by installing a bond wire  232   c  between the outer pad of IO buffer  210   c  and package pin  120   q  and bond wire  232   d  between the outer pad of IO buffer  210   d  and package pin  120   r . In this case, the inner pads of IO buffer  210   c  and IO buffer  210   d  are left unused. Interface E is connected by installing a bond wire  232   j  between the outer pad of IO buffer  210   o  and package pin  120   k  and bond wire  232   k  between the outer pad of IO buffer  210   p  and package pin  120   l . In this case, the inner pads of IO buffer  210   o  and IO buffer  210   p  are left unused. While  FIG. 2  are shown as including two bond pads per IO buffer, based on the disclosure provided herein, one of ordinary skill in the art will recognize that embodiments with three or more bond pads per TO buffer may be implemented in accordance with other embodiments of the present invention. 
     Turning to  FIG. 3 , a semiconductor die  300  is depicted in relation to a number of package pins  120 . Semiconductor die  300  includes a number of IO buffers  320  that are bonded using bond wires  340  to a ground plane  350  indicated by the lined area surrounding semiconductor die  300 , or to a power plane  360  indicated by the stippled area surrounding semiconductor die  300 . In particular, IO buffer  320   a , IO buffer  320   c , IO buffer  320   e  and IO buffer  320   g  are bonded to ground plane  350 ; and IO buffer  320   b , IO buffer  320   d , IO buffer  320   f  and IO buffer  320   f  are bonded to power plane  360 . Each of the aforementioned IO buffers includes only a single bond pad indicated by a cross hatched region on the respective IO buffer. 
     Other IO buffers  310  are disposed in proximity to package pins  120 . Each of IO buffers  310  includes an inner bond pad  312  shown as a cross hatched area located on the core side of the respective IO buffer  310 , and an outer bond pad  311  shown as another cross hatched area located on the package pin side of the respective IO buffer  310 . The inner and outer bond pads of IO buffers  310  may be utilized in similar fashion to that described above in relation to  FIG. 2 . In contrast to that described in relation to  FIG. 2   a  above, the inner and outer bond pads are staggered between adjacent IO buffers  310  such that the outer bond pad on one IO buffer is closer to the outer edge of die  300  than the corresponding outer bond pad of an adjacent IO buffer. Similarly, the inner bond pad of one IO buffer is closer to the core of semiconductor die  300  than the inner bond pad of an adjacent IO buffer. Such staggering may be used to reduce the pitch of any bond wires ultimately installed between an IO buffer  310  and a proximate package pin  120 . Based on the disclosure provided herein, one of ordinary skill in the art will recognize other staggering schemes that may implemented in relation to one or more embodiments of the present invention. 
     Turning to  FIG. 4 , a cross sectional diagram of an IO buffer  210  of  FIG. 2  is depicted. As shown, IO buffer  210  includes a semiconductor substrate  440  with a number of metal layers  450 ,  460 ,  470 ,  480 ,  490  disposed thereon. In some cases, metal layers  450 ,  460 ,  470 ,  480 ,  490  are implemented in copper. Each of metal layers  450 ,  460 ,  470 ,  480 ,  490  is separated from adjacent metal layers and semiconductor substrate  440  by insulating layers  445 ,  455 ,  465 ,  475 ,  485 ,  495 . In addition, IO buffer  210  includes inner bond pad  212  and outer bond pad  211 . Inner bond pad  212  includes two bond pad layers  430 ,  434  interconnected by a number of vias  436 . Connection of multiple layers may reduce stress caused by mechanical movement between the layers. Inner bond pad  212  is further connected or connectable using a conductive interconnect  432 . In some case, conductive interconnect  432  is implemented in aluminum along with pad layer  430 . Outer bond pad  211  includes two bond pad layers  431 ,  435  interconnected by a number of vias  437 . Again, connection of multiple layers may reduce stress caused by mechanical movement between the layers. Outer bond pad  211  is connected to underlying circuitry by way of a via  439 . As shown, via  439  electrically couples bond pad  211  to a wire on metal layer  490 , but could connect bond pad  211  to lower metal layers where such was desired. A bond wire  232  may be bonded to either inner bond pad  212  or outer bond pad  211  depending upon the desired circuit connection. 
     Turning to  FIG. 5 , a flow diagram  500  shows a process for manufacturing and packaging a multi-mode semiconductor device in accordance with one or more embodiments of the present invention. Following flow diagram  500 , a standard semiconductor die is designed that includes a plurality of interfaces (block  510 ). One or more of the plurality of interfaces are selected to be made available at the package pins (block  520 ), and a package suitable for encapsulating the semiconductor die is selected (block  530 ). The aforementioned processes result, for example, in the reduction of package pins shown between  FIG. 2   a  and  FIG. 2   b  above. It is then determined if some of the IO buffers associated with interfaces that are not to be made available at the package pins may be reused to implement one or more of the interfaces that are to be included (block  540 ). Thus, using the example shown in the transition between  FIG. 2   a  and  FIG. 2   b  above, it is determined that the interface that is by default served by IO buffers  210   j ,  210   k ,  210   l ,  210   m ,  210   n  will be relocated to reuse the otherwise unused IO buffers  210   e ,  210   f ,  210   g ,  210   h ,  210   i . Further, the interface that is by default served by IO buffers  210   q ,  210   r  will be relocated to reuse the otherwise unused IO buffers  210   a ,  210   b . In some cases, this determination can be made by determining whether one of the otherwise unused IO buffers is closer to a package pin than one of the used IO buffers. 
     Once the aforementioned determination is made, a conductive interconnect is formed to electrically couple the inner bond pads of IO buffers that are to be reused with the inner bond pads of IO buffers that are to be relocated (block  560 ). Forming the conductive interconnect may be done using any of a number of processes known in the art including, but not limited to, conductive material deposition; a combination of conductive material deposition and etch; forming a trench in the semiconductor die and filling the trench with a conductive material; or forming a trench in the semiconductor die, filling the trench with a conductive material, and removing a portion of the conductive material by chemical, mechanical polishing. The aforementioned process results in conductive interconnects  231  depicted in  FIG. 2   b  above. Bond wires are attached to the utilized bond pad of each of the IO buffers (block  570 ). Using the example of  FIG. 2   b , the aforementioned step includes attaching a bond wire to the inner bond pad of IO buffers that are being reused (e.g., IO buffer  210   a ), and attaching a bond wire to the outer bond pad of IO buffers that are not reused (e.g., IO buffer  210   c ). In addition, bond wires are placed from the selected IO buffers to select package pins (block  580 ). This results in, for example, bond wires  232  from the various IO buffers  210  to package pins  120  of  FIG. 2   b.    
     Turning to  FIG. 6 , access to IO buffers on multiple die implemented on a wafer  600  utilizing embodiments of the present invention applied to wafer probe scenarios are described. It should be emphasized that wafer  600  includes a number of die  610  arranged such that IO buffers along some sides of the die are not easily accessed during wafer probe. Die  610  includes fifteen dual and triple pad IO buffers along the left hand side designated as elements  614 , fifteen dual and triple pad IO buffers along the right hand side designated as elements  616 , eleven dual pad IO buffers along the bottom side designated as elements  610 , and eleven dual pad IO buffers along the top side designated as elements  612 . Each of the dual and triple pad IO buffers are implemented and usable in accordance with the IO buffers described above in relation to  FIGS. 2-5 . Other die  610  may be located along the edges defined by IO buffers  614  and IO buffers  616 , and yet one or more of the edges of the depicted die  610  defined by IO buffers  610  and IO buffers  612  may not be surrounded by bordering die. As such, access to IO buffers  610 ,  612  may be easier to access during wafer probe test when compared with IO buffers  614 ,  616 . Where such is the case, one or more of IO buffers  614 ,  616  may be re-routed to IO buffers  610 ,  612  as shown using one of the various embodiments of the present invention discussed above in relation to  FIGS. 2-5 . Based on the disclosure provided herein, one of ordinary skill in the art will recognize a variety of re-routing that may be done in accordance with one or more embodiments of the present invention. 
     Turning to  FIGS. 7   a - 7   b , two exemplary implementations of multi-die devices  700 ,  720  utilizing re-routing possibilities to provide for binding to multiple die within a single package in accordance with embodiments of the present invention are described. As shown in  FIG. 7   a , multi-die device  700  includes a smaller die  750  stacked on top of a larger die  710 . Larger die  710  includes fifteen dual pad IO buffers along the left hand side designated as elements  714 , fifteen dual pad IO buffers along the right hand side designated as elements  716 , eleven dual pad IO buffers along the bottom side designated as elements  710 , and eleven dual pad IO buffers along the top side designated as elements  712 . Each of the dual pad IO buffers are implemented and usable in accordance with the IO buffers described above in relation to  FIGS. 2-5 . 
     Smaller die  750  includes five dual pad IO buffers along the left hand side designated as elements  764 , five dual pad IO buffers along the right hand side designated as elements  766 , five dual pad IO buffers along the bottom side designated as elements  760 , and five dual pad  10  buffers along the top side designated as elements  762 . Again, each of the dual pad IO buffers is implemented and usable in accordance with the IO buffers described above in relation to  FIGS. 2-5 . In the process of binding IO buffers to package pins, the location of one or more of the aforementioned IO buffers may conflict with other of the IO buffers. Where such a conflict exists, one or more of the conflicting IO buffers may be re-routed to another IO buffer location to thus avoid the conflict. Based on the disclosure provided herein, one of ordinary skill in the art will recognize a variety of other approaches to IO buffer re-routing to allow for a simplified bonding process in accordance with one or more embodiments of the present invention. 
     Another example of IO re-routing that may be used in relation to multi-die devices  720  is shown in  FIG. 7   b . As shown in  FIG. 7   b , two dies  730 ,  770  are stacked next to each other. Die  730  includes five dual pad IO buffers along the left hand side designated as elements  744 , five dual pad IO buffers along the right hand side designated as elements  746 , five dual pad IO buffers along the bottom side designated as elements  740 , and five dual pad IO buffers along the top side designated as elements  742 . Again, each of the dual pad IO buffers is implemented and usable in accordance with the IO buffers described above in relation to  FIGS. 2-5 . Because of the location of dual pad IO buffers  742 ,  744 ,  746  around an outer edge, they are relatively easy to access for bonding purposes. In contrast, dual pad IO buffers  740  may be relatively hard to access for package pin bonding purposes. Die  770  includes five dual pad IO buffers along the left hand side designated as elements  784 , five dual pad IO buffers along the right hand side designated as elements  786 , five dual pad IO buffers along the bottom side designated as elements  780 , and five dual pad IO buffers along the top side designated as elements  782 . Again, each of the dual pad IO buffers is implemented and usable in accordance with the IO buffers described above in relation to  FIGS. 2-5 . Because of the location of dual pad buffers  780 ,  784 ,  786  around an outer edge, they are relatively easy to access for bonding purposes. In contrast, dual pad IO buffers  782  may be relatively hard to access for bonding purposes. To alleviate the difficulty in bonding to IO buffers  740  and IO buffers  782 , one or more of IO buffers  740  and IO buffers  782  may be connected to other IO buffers on the same respective die using connection techniques discussed above in relation to  FIGS. 2-5 . Again, based on the disclosure provided herein, one of ordinary skill in the art will recognize a variety of other uses for re-routing IO buffers in accordance with one or more of the various embodiments of the present invention. 
     In conclusion, the present invention provides novel systems, devices, methods and arrangements for semiconductor device implementation. While detailed descriptions of one or more embodiments of the invention have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.