Abstract:
In accordance with the present invention, there is provided a semiconductor package or device including a uniquely configured leadframe sized and configured to maximize the available number of exposed lands or I/O&#39;s in the semiconductor device. More particularly, the semiconductor device of the present invention includes a die pad (or die paddle) defining multiple peripheral edge segments. In addition, the semiconductor device includes a plurality of lands which are provided in a prescribed arrangement. Connected to the top surface of the die pad is at least one semiconductor die which is electrically connected to at least some of the lands. At least portions of the die pad, the lands, and the semiconductor die are encapsulated by the package body, with at least portions of the bottom surfaces of the die pad and the lands being exposed in a common exterior surface of the package body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to integrated circuit package technology and, more particularly, to an enhanced capacity semiconductor device or package which includes an increased number of lands serving as I/O&#39;s, the lands being provided in a prescribed arrangement and exposed within a common exterior surface of the package body of the device. 
     2. Description of the Related Art 
     Semiconductor dies are conventionally enclosed in plastic packages that provide protection from hostile environments and enable electrical interconnection between the semiconductor die and an underlying substrate such as a printed circuit board (PCB) or motherboard. The elements of such a package include a metal leadframe, an integrated circuit or semiconductor die, bonding material to attach the semiconductor die to the leadframe, bond wires which electrically connect pads on the semiconductor die to individual leads of the leadframe, and a hard plastic encapsulant material which covers the other components and forms the exterior of the semiconductor package commonly referred to as the package body. 
     The leadframe is the central supporting structure of such a package, and is typically fabricated by chemically etching or mechanically stamping a metal strip. A portion of the leadframe is internal to the package, i.e., completely surrounded by the plastic encapsulant or package body. Portions of the leads of the leadframe may extend externally from the package body or may be partially exposed therein for use in electrically connecting the package to another component. In certain semiconductor packages, a portion of the die pad of the leadframe also remains exposed within the package body. 
     Leadframes for semiconductor devices or packages can be largely classified into copper-based leadframes (copper/iron/phosphorous: 99.8/0.01/0.025), copper alloy-based leadframes (copper/chromium/tin/zinc: 99.0/0.25/0.22), and alloy 42-based leadframes (iron/nickel; 58.0/42.0) according to the composition of the elements or materials included in the leadframe. Exemplary semiconductor devices employing leadframes include a through-hole mounting dual type inline package (DIP), a surface mounting type quad flat package (QFP), and a small outline package (SOP). In recent years, land grid array type semiconductor devices using leadframes have also been developed for use in certain applications. 
     The aforementioned semiconductor devices are particularly advantageous for their smaller size and superior electrical performance. In the electronics industry and, in particular, in high frequency applications such hard disk drives, digital television and other consumer electronics, there is an increasing need for exposed pad or land semiconductor devices of increased functional capacity, coupled with reduced size and weight. In view of this need, conventional leadframe structures as currently known and integrated into existing semiconductor devices often prove to be unsatisfactory. The present invention provides a semiconductor device which addresses the aforementioned needs by providing increased I/O with a reduced overall size. The semiconductor device of the present invention includes a leadframe having an increased number of lands which are provided in a prescribed arrangement and exposed within a common exterior surface of the package body of the device. The leadframe of the semiconductor device may be fabricated in accordance with standard, low-cost forming techniques, with sawing, punching, etching, or other material removal processes being completed during the fabrication of the semiconductor device to effectively electrically isolate various structural features from each other therein. These, as well as other features and attributes of the present invention will be discussed in more detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These, as well as other features of the present invention, will become more apparent upon reference to the drawings wherein: 
         FIG. 1  is a top plan view of an unsingulated leadframe which is integrated into a semiconductor device or package constructed in accordance with a first embodiment of the present invention; 
         FIG. 2  is an enlargement of the region A of  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the leadframe taken along line B-B′ of  FIG. 1 ; 
         FIG. 4  is a cross-sectional view identical to  FIG. 3  but depicting the leadframe subsequent to the completion of a partial etching process thereon; 
         FIG. 5  is a top plan view of an unsingulated leadframe which is integrated into a semiconductor device or package constructed in accordance with a second embodiment of the present invention; 
         FIG. 6  is an enlargement of the region C of  FIG. 5 ; 
         FIG. 7  is a cross-sectional view of the leadframe taken along line D-D′ of  FIG. 5 ; 
         FIG. 8  is a cross-sectional view identical to  FIG. 7  but depicting the leadframe subsequent to the completion of a partial etching process thereon; 
         FIG. 9  is a top plan view of the semiconductor device of the first embodiment as fabricated to include the leadframe shown in  FIGS. 1-4 ; 
         FIG. 10  is a top plan view of the semiconductor device of the first embodiment similar to  FIG. 9 , but with the package body partially removed so as to depict the internal features thereof; 
         FIG. 11  is a bottom plan view of the semiconductor device of the first embodiment as fabricated to include the leadframe shown in  FIGS. 1-4 ; 
         FIG. 12  is a cross-sectional view of the semiconductor device of the first embodiment taken along line E-E′ of  FIG. 10 ; 
         FIG. 13  is a top plan view of the semiconductor device of the second embodiment as fabricated to include the leadframe shown in  FIGS. 5-8 ; 
         FIG. 14  is a bottom plan view of the semiconductor device of the second embodiment as fabricated to include the leadframe shown in  FIGS. 5-8 ; 
         FIG. 15  is a top plan view of the semiconductor device of the second embodiment similar to  FIG. 13 , but with the package body partially removed so as to depict the internal features thereof; 
         FIG. 16  is a cross-sectional view of the semiconductor device of the second embodiment taken along line F-F′ of  FIG. 15 ; 
         FIG. 17  is a flow chart illustrating an exemplary fabrication method for the semiconductor device of the first embodiment shown in  FIGS. 9-12 ; and 
         FIGS. 18A-18I  are views illustrating an exemplary fabrication method for the semiconductor device of the first embodiment shown in  FIGS. 9-12 . 
     
    
    
     Common reference numerals are used throughout the drawings and detailed description to indicate like elements. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the present invention only, and not for purposes of limiting the same,  FIGS. 9-12  depict a semiconductor package or device  1100  constructed in accordance with a first embodiment of the present invention. The leadframe  100  integrated into the semiconductor package  1100  is shown in its unsingulated state in  FIGS. 1-4 . 
     Referring now to  FIGS. 1-4 , the leadframe  100  comprises a generally quadrangular (e.g., square) die paddle or die pad  110  which defines four peripheral edge segments and four corner regions. The peripheral edge segments of the die pad  110  are defined by a peripheral region thereof. Additionally, when viewed from the perspective shown in  FIGS. 3 and 4 , the die pad  110  defines opposed, generally planar top and bottom surfaces. As is further most easily seen in  FIGS. 3 and 4 , the die pad  110  of the leadframe  100  is not of uniform thickness. Rather, a peripheral portion of the bottom surface of the die pad  110  is partially etched (e.g., half-etched) to define an etched surface  111 . More particularly, the etched surface  111 , which is recessed relative to the remainder of the bottom surface of the die pad  110 , extends about the entire periphery of the die pad  100 , and thus along each of the peripheral edge segments defined thereby. In  FIGS. 1 and 2 , the etched surface  111  in the bottom surface of the die pad  110  is indicated by the condensed hatching which slopes downwardly from right to left. The die pad  110  further includes a plurality of elongated holes or slots  112  which are disposed in the peripheral portion thereof, and extend between the top surface and the etched surface  111 . As seen in  FIG. 1 , the slots  112  are generally aligned with each other in end-to-end fashion, and arranged in a generally quadrangular pattern so as to extend along and in relative close proximity to the peripheral edge segments of the die pad  110 . The use of the slots  112  will be discussed in more detail below. 
     As will be also discussed in more detail below, in the fabrication process for the semiconductor device  1100  including the leadframe  100 , a semiconductor die is attached to the top surface of the die pad  110  through the use of an adhesive layer, with an encapsulant material thereafter being applied to the semiconductor die and the leadframe  100  to form the package body of the semiconductor device  1100 . Advantageously, the etched surface  111  formed in the peripheral portion of the bottom surface of the die pad  110  as indicated above effectively increases the distance along which moisture must travel to reach the semiconductor die mounted to the top surface of the die pad  110 . As a result, such semiconductor die is safely protected against moisture in the completed semiconductor device  1100 . Additionally, the flow of encapsulant material over the etched surface  111  during the formation of the package body of the semiconductor device  1100  facilitates the creation of a mechanical interlock between the package body and the die pad  110 . Further, the inclusion of the slots  112  in the die pad  110  prevents any undesirable flow of the adhesive layer used to secure the semiconductor die to the top surface of the die pad  110  to and over the peripheral edge segments thereof. 
     The leadframe  100  of the semiconductor device  1100  further comprises a plurality of connect bars  120  and a plurality of lands  130 . The connect bars  120  are segregated into first connect bars  121 , second connect bars  122  and corner connect bars  120   a . Similarly, the lands are segregated into first lands  131 , second lands  132  and corner lands  130   a.    
     As best seen in  FIGS. 1 and 2 , the first connect bars  121  are integrally connected to extend between the die pad  110  and a generally quadrangular outer frame or dambar (not shown) of the unsingulated leadframe  100  which circumvents the die pad  110 . As further seen in  FIG. 1 , the first connect bars  121  are segregated into four (4) sets of seven (7) each, with the first connect bars  121  of each set extending between one of the peripheral edge segments of the die pad  110  and a corresponding one of the four peripheral edge segments of the surrounding outer frame or dambar. Of the first connect bars  121  of each set, the central or middle first connect bar  121  has a straight, generally linear configuration, with the remaining first connect bars  121  of the same set each having a non-linear configuration. Those of ordinary skill in the art will recognize that the inclusion of seven first connect bars  121  in each set thereof is exemplary only, and that fewer or greater first connect bars  121  may be included in each such set without the departing from the spirit and scope of the present invention. 
     As seen in  FIGS. 1-3 , the first connect bars  121  are not of uniform thickness. Rather, as is most easily seen from the perspective shown in  FIGS. 3 and 4 , portions of the bottom surface of each of the first connect bars  121  are subjected to a partial etching process (e.g., are half-etched) that results in each of the first connect bars  121  having two (2) regions which are of increased thickness in comparison to the remainder thereof. One of these increased thickness regions of the middle first connect bar  121  and the outermost pair of the first connect bars  121  of each set defines a second land  132  thereof. Similarly, one of these increased thickness regions of each of the remaining first connect bars  121  of the same set defines a first land  131  thereof. As seen in  FIG. 1 , the second lands  132  of the first connect bars  121  of each set are disposed closer to the die pad  110  than the first lands  131  of the remaining first connect bars  121  of the same set. The increased thickness region of each of the first connect bars  121  which does not define the first land  131  or second land  132  thereof defines a connector  123  of such first connect bar  121 . 
     As seen in  FIGS. 3 and 4 , the generally planar top surfaces of the first connect bars  121  extend in generally co-planar relation to the top surface of the die pad  110 . Additionally, the first and second lands  131 ,  132  of the first connect bars  121  and distal surfaces defined by the connectors  123  thereof each extend in generally co-planar relation to the bottom surface of the die pad  110 . The etched surfaces defined by each first connect bar  121  extend in generally co-planar relation to the etched surface  111  of the die pad  110 . As will be discussed in more detail below, during the fabrication process for the semiconductor device  1100  including the leadframe  100 , the connectors  123  of the first connect bars  121  are removed from the leadframe  100 , and the dambar also removed, to electrically isolate the first connect bars  121  from the die pad  110 , the second connect bars  122 , the corner connect bars  120   a , and each other. As seen in  FIG. 4 , it is contemplated that such removal can be simplified by further subjecting a portion of the top surface of each of the first connect bars  121  to a partial etching process (e.g., a half-etched) as results in each of the connectors  123  having a notch  123   a  formed therein. The etching of the notch  123   a  into each connector  123  effectively reduces the original thickness thereof (equal to the full thickness of the first connect bar  121 ) by approximately one-half. As will also be discussed in more detail below, the encapsulant material used to form the package body of the semiconductor device  100  effectively covers both the lop surfaces and etched surfaces of the first connect bars  121 , thus resulting in almost the entirety of each of the first connect bars  121  being encapsulated by the package body, and only the first and second lands  131 ,  132  thereof being exposed in the bottom surface of the package body. 
     The second connect bars  122  of the leadframe  100  are integrally connected to the outer frame or dambar of the unsingulated leadframe  100 , and extend inwardly toward die pad  110 . However, none of the second connect bars  122  is directly attached to the die pad  110 . As seen in  FIG. 1 , the second connect bars  122  are also segregated into four (4) sets, with the first connect bars  121  of each set extending between one of the peripheral edge segments of the die pad  110  and a corresponding one of the four peripheral edge segments of the surrounding outer frame or dambar. Each of the second connect bars  122  has a non-linear configuration. Additionally, each of the first connect bars  121  extends between a corresponding pair of the second connect bars  122 . 
     Like the first connect bars  121 , the second connect bars  122  are not of uniform thickness. Rather, portions of the bottom surface of each of the second connect bars  122  are subjected to a partial etching process (e.g., are half-etched) as results in each of the second connect bars  122  having one region which is of increased thickness in comparison to the remainder thereof. In roughly half of the second connect bars  122  of each set, this increased thickness region defines a second land  132  thereof. The increased thickness region of each of the remaining second connect bars  122  of the same set defines a first land  131  thereof. As seen in  FIG. 1 , the second lands  132  of the second connect bars  122  of each set are disposed closer to the die pad  110  than the first lands  131  of the remaining second connect bars  122  of the same set. Additionally, the first and second lands  131 ,  132  of the second connect bars  122  of each set are staggered or offset relative to each other. 
     In the leadframe  100 , the generally planar top surfaces of the second connect bars  122  extend in generally co-planar relation to the top surface of the die pad  110 . Additionally, the first and second lands  131 ,  132  of the second connect bars  122  each extend in generally co-planar relation to the bottom surface of the die pad  110 . The etched surfaces defined by each second connect bar  122  extend and generally co-planar relation to the etched surface  111  of the die pad  110 . As will also be discussed in more detail below, during the fabrication process for the semiconductor device  1100  including the leadframe  100 , the removal of the dambar from the leadframe  100  effectively electrically isolates the second connect bars  122  from each other, and from the first connect bars  121  and the corner connect bars  120   a . As will also be discussed in more detail below, the encapsulant material used to form the package body of the semiconductor device  100  effectively covers both the top surfaces and etched surfaces of the second connect bars  122 , thus resulting in almost the entirety of each of the second connect bars  122  being encapsulated by the package body, and only the first and second lands  131 ,  132  thereof being exposed in the bottom surface of the package body. 
     The corner connect bars  120   a  of the leadframe  100  are integrally connected to the outer frame or dambar of the unsingulated leadframe  100 , and extend inwardly toward die pad  110 . However, none of the corner connect bars  120   a  is directly attached to the die pad  110 . Each of the corner connect bars  120   a  has a non-linear configuration. Also, as seen in  FIG. 1 , the corner connect bars  120   a  are segregated into four (4) sets. More particularly, inner portions of the corner connect bars  120   a  of each set extend generally diagonally from a respective one of the corner regions of the die pad  110  in spaced relation thereto and in side-by-side relation to each other, with outer portions of the corner connect bars  120   a  of the same set extending to corresponding ones of the four peripheral edge segments of the surrounding outer frame or dambar. 
     The corner connect bars  120   a  are also not of uniform thickness. Rather, portions of the bottom surface of each of the corner connect bars  120   a  are subjected to a partial etching process (e.g., are half-etched) as results in each of the corner connect bars  120   a  having one region which is of increased thickness in comparison to the remainder thereof. In each of the corner connect bars  120   a  of each set, this increased thickness region defines a corner land  130   a  thereof. As seen in  FIG. 1 , the corner land  130   a  defined by each of the corner connect bars  120   a  of each set is generally aligned with the first lands  131  defined by a corresponding set of the interleaved first and second connect bars  121 ,  122 . 
     In the leadframe  100 , the generally planar top surfaces of the corner connect bars  120   a  extend in generally co-planar relation to the top surface of the die pad  110 . Additionally, the corner lands  130   a  of the corner connect bars  120   a  each extend in generally co-planar relation to the bottom surface of the die pad  110 . The etched surfaces defined by each corner connect bar  120   a  extend and generally co-planar relation to the etched surface  111  of the die pad  110 . As will also be discussed in more detail below, during the fabrication process for the semiconductor device  1100  including the leadframe  100 , the removal of the dambar from the leadframe  100  effectively electrically isolates the corner connect bars  120   a  from each other, and from the first and second connect bars  121 ,  122 . As will also be discussed in more detail below, the encapsulant material used to form the package body of the semiconductor device  1100  effectively covers both the top surfaces and etched surfaces of the corner connect bars  120   a , thus resulting in almost the entirety of each of the corner connect bars  120   a  being encapsulated by the package body, and only the corner lands  130   a  thereof being exposed in the bottom surface of the package body. 
     As is most apparent from  FIG. 1 , due to the structural features of the leadframe  100  as described above, the second lands  132  defined by the first and second connect bars  121 ,  122  are arranged in a generally quadrangular pattern which circumvents the die pad  110 . Similarly, the first lands  131  defined by the first and second connect bars  121 ,  122  and the corner lands  130   a  defined by the corner connect bars  120   a  are arranged in a generally quadrangular pattern which circumvents the second lands  132 , i.e., the second lands  132  are generally concentrically positioned between the die pad  110  and the first lands  131  and corner lands  130   a . Additionally, the second lands  132 , like the first and second connect bars  121 ,  122 , are segregated into four (4) sets, with each such set of the second lands  132  extending along a respective one of the peripheral edge segments defined by die pad  110 . Similarly, the first lands  131  are also segregated into the four (4) sets, with each such set also extending along respective one of peripheral edge segments defined by the die pad  110 . As indicated above, each of the corner lands  130   a  is aligned with a corresponding set of the first lands  131 . Further, each set of the second lands  132  collectively defined by corresponding sets of the first and second connect bars  121 ,  122  is staggered or offset relative to a corresponding set of the first and corner lands  131 ,  130   a  collectively defined by corresponding sets of the first, second and corner connect bars  121 ,  122 ,  120   a.    
     The leadframe  100  may be fabricated from a conventional metal material, such as copper, copper alloy, steel plated with copper, or a functional equivalent. However, those of ordinary skill in the art will recognize that the present invention is not limited to any particular material for the leadframe  100 . Additionally, the number of first and second connect bars  121 ,  122  shown in  FIG. 1  is for illustrative purposes only, and may be modified according to application field. Along these lines, the first and second connect bars  121 ,  122  may have designs or configurations varying from those shown in  FIG. 1  without departing from the spirit and scope of the present invention. Additionally, though the first, second and corner connect bars  121 ,  122 ,  120   a  are each shown as being segregated into four sets, it will be recognized that fewer sets thereof may be provided, and may be arranged along any combination of two or three of the peripheral sides or corners of the die pad  110 . It is further contemplated that the leadframe  100  may be fabricated through the implementation of a chemical etching process or alternatively a mechanical stamping process. 
     Referring now to  FIGS. 9-12 , the semiconductor device or package  1100  as fabricated to include the leadframe  100  is shown in detail. As will be recognized by those of ordinary skill in the art, in the completed semiconductor device  1100  shown in  FIGS. 9-12 , the dambar and connectors  123  are each singulated or removed from the leadframe  100  to facilitate the electrical isolation of the various structural features of the leadframe  100  from each other. As indicated above, the dambar and the connectors  123  are singulated in a manner wherein the first, second and corner connect bars  121 ,  122 ,  120   a , and hence the first, second and corner lands  131 ,  132 ,  130   a , are electrically isolated from each other, and from the die pad  110 . 
     In the semiconductor device  1100 , a semiconductor die  140  is attached to the top surface of the die pad  110  through the use of an adhesive layer  141 . The semiconductor die  140  includes a plurality of bond pads  142  which are disposed on the top surface thereof opposite the bottom surface adhered to the adhesive layer  141 . The bond pads  142  are used to deliver and receive electrical signals. 
     The semiconductor device  1100  further comprises a plurality of conductive wires  150  which are used to electrically connect the bond pads  142  of the semiconductor die  140  to respective ones of the first, second and corner connect bars  121 ,  122 ,  120   a , and hence the first, second and corner lands  131 ,  132 ,  130   a . More particularly, as seen in  FIG. 10 , the wires  150  are extended to the top surfaces of respective ones of the first, second and corner connect bars  121 ,  122 ,  120   a . The conductive wires  150  may be fabricated from aluminum, copper, gold, silver, or a functional equivalent. However, those of ordinary skill in the art will recognize that the present invention is not limited to any particular material for the wires  150 . One or more conductive wires  150  may also be used to electrically connect one or more bond pads  142  of the semiconductor die  140  directly to the die pad  110 . 
     In the semiconductor device  1100 , the die pad  110 , the first, second and corner connect bars  121 ,  122 ,  120   a , the semiconductor die  140  and the conductive wires  150  are at least partially encapsulated or covered by an encapsulant material which, upon hardening, forms the package body  160  of the semiconductor device  1100 . More particularly, the package body  160  covers the entirety of the die pad  110  (including the etched surface  111 ) except for the bottom surface thereof which is circumvented by the etched surface  111 . The package body  160  also covers the top and etched surfaces of the first, second and corner connect bars  121 ,  122 ,  120   a , as well as portions of the side surfaces thereof. However, the package body  160  does not cover the those surfaces of the first, second and corner connect bars  121 ,  122 ,  120   a , which define the first, second and corner lands  131 ,  132 ,  130   a . As such, in the completed semiconductor device  1100 , the bottom surface of the die pad  110 , and the first, second and corner lands  131 ,  132 ,  130   a  are exposed in and substantially flush with a generally planar bottom surface  161  defined by the package body  160 . During the process of fabricating the semiconductor device  1100 , the dambar and portions of the connectors  123  of the first connect bars  121  are also not covered by the package body  160  so that they may be removed from the leadframe  100 . 
     Referring now to  FIG. 17 , there is provided a flow chart which sets forth an exemplary method for fabricating the semiconductor device  1100  of the present invention. The method comprises the steps of preparing the leadframe (S 1 ), semiconductor die attachment (S 2 ), wire bonding (S 3 ), encapsulation (S 4 ), partial etching (S 5 ), and singulation (S 6 ).  FIGS. 18A-18I  provide illustrations corresponding to these particular steps, as will be discussed in more detail below. 
     Referring now to  FIGS. 18A and 18B , in the initial step S 1  of the fabrication process for the semiconductor device  1100 , the leadframe  100  is provided by etching a suitably shaped piece of metal material to define the above-described structural features. Thereafter, as illustrated in  FIGS. 18C and 18D , step S 2  is completed wherein the semiconductor die  140  having the bond pads  142  is attached to the top surface of the die pad  110  of the leadframe  100  through the use of the adhesive layer  141 . The adhesive layer  141  can be selected from well known liquid epoxy adhesives, adhesive films and adhesive tapes, as well as equivalents thereto. 
     Referring now to  FIGS. 18E and 18F , in the next step S 3  of the fabrication process, the conductive wires  150  are used to electrically interconnect the semiconductor die  140  to the leadframe  100  in the aforementioned manner. Specifically, the bond pads  142  of the semiconductor die  140  are electrically connected to the top surfaces of the first, second and corner connect bars  121 ,  122 ,  120   a . Though not shown, as indicated above, one or more conductive wires  150  may also be used to electrically connect one or more bond pads  142  of the semiconductor die  140  directly to the die pad  110 , allowing for the use of the die pad  110  as a ground region. 
     Referring now to  FIGS. 18G and 18H , in the next step S 4  of the fabrication process for the semiconductor device  1100 , portions of the leadframe  100 , the semiconductor die  140  and the conductive wires  150  are encapsulated with an encapsulant material which, upon hardening, forms the package body  160  of the semiconductor device  1100 . More particularly, as indicated above, the package body  160  covers the entirety of the die pad  110  (including the etched surface  111 ) except for the bottom surface thereof which is circumvented by the etched surface  111 . The package body  160  also covers the top and etched surfaces of the first, second and corner connect bars  121 ,  122 ,  120   a , as well as portions of the side surfaces thereof. However, the package body  730  does not cover the those surfaces of the first, second and corner connect bars  121 ,  122 ,  120   a , which define the first, second and corner lands  131 ,  132 ,  130   a . As such, in the completed semiconductor device  1100 , the bottom surface of the die pad  110 , and the first, second and corner lands  131 ,  132 ,  130   a  are exposed in and substantially flush with a generally planar bottom surface  161  defined by the package body  160 . The dambar and portions of the connectors  123  of the first connect bars  121  are also not covered by the package body  160  so that they may be removed from the leadframe  100  in a subsequent step of the fabrication process. 
     Referring now to  FIG. 18I , in the next step S 5  of the fabrication process for the semiconductor device  1100 , the removal of the connectors  123  of the first connect bars  121  is facilitated by the completion of an etching process. More particularly, it is contemplated that a photoresist may be applied to the bottom surface  161  of the package body  160 , and in particular on to the exposed bottom surface of the die pad  110  and to the first, second and corner lands  131 ,  132 ,  130   a . The photoresist is then patterned so as to facilitate the necessary exposure of those portions of the connectors  123  which are exposed in the bottom surface  161  of the package body  160 . A wet etching process is then performed as facilitates the removal of the connectors  123 , and thus the separation of the first connect bars  121  from the die pad  110 . As previously explained, during the process of forming the leadframe  100  in accordance with step S 1 , the notches  123   a  may be etched into respective ones of the connectors  123  as effectively reduces the thickness thereof and simplifies the process of removing the same by the application of a suitable etchant thereto. As seen in  FIGS. 11 and 18I , a trench or recess  160   a  may be formed in the bottom surface  161  of the package body  160  as an artifact of the etching process used to facilitate the removal of the connectors  123 . 
     In the last step S 6  of the fabrication process for the semiconductor device  1100 , the outer frame or dambar is trimmed or removed by cutting with a cutting tool so that the first, second and corner connect bars  121 ,  122 ,  120   a , and hence the first, second and corner lands  131 .  132 ,  130   a , are electrically isolated from each other and from the die pad  110 . It is contemplated that the dambar will be positioned outside of the package body  160  to allow for the removal thereof from the leadframe  100 , and is removed by cutting the same with a dambar cutting tool. It is contemplated that the removal of the dambar may also result in distal, outer ends of the first, second and corner connect bars  121 ,  122 ,  120   a  being exposed in and substantially flush with a peripheral outer surface of the package body  160 . 
     In the semiconductor device  1100 , the structural attributes of the leadframe  100  allow the lengths of the conductive wires  150  extending between the bond pads  142  of the semiconductor die  140  and the first, second and corner connect bars  121 ,  122 ,  120   a  to be minimized, thereby reducing the complexity of and fabricating costs related to the semiconductor device  1100 . Further, the leadframe  100  is uniquely configured so that conventional tie bars which would otherwise extend diagonally from each of the four corners of the die pad  110  are replaced with each set of the corner connect bars  120   a  which are configured to extend to terminate in close proximity to the die pad  110 . The inclusion of the corner connect bars  120   a , and hence the corner lands  130   a  defined thereby, effectively increases the number of input/output terminals in the semiconductor device  1100 , with the structural attributes of the corner connect bars  120   a  allowing for the lengths of the conductive wires  150  extending thereto to be decreased or minimized, thereby reducing the complexity of and fabricating costs related to the semiconductor device  1100  as indicated above. 
     Referring now to  FIGS. 5-8 , there is shown an unsingulated leadframe  200  which is integrated into a semiconductor device  1200  constructed in accordance with a second embodiment of the present invention, and shown in  FIGS. 13-16 . The leadframe  200  comprises a generally quadrangular (e.g., square) die paddle or die pad  210  which defines four peripheral edge segments and four corner regions. The peripheral edge segments of the die pad  210  are defined by a peripheral region thereof. Additionally, when viewed from the perspective shown in  FIGS. 7 and 8 , the die pad  210  defines opposed, generally planar top and bottom surfaces. As is further most easily seen in  FIGS. 7 and 8 , the die pad  210  of the leadframe  200  is not of uniform thickness. Rather, a peripheral portion of the bottom surface of the die pad  210  is partially etched (e.g., half-etched) to define an etched surface  211 . More particularly, the etched surface  211 , which is recessed relative to the remainder of the bottom surface of the die pad  210 , extends about the entire periphery of the die pad  200 , and thus along each of the peripheral edge segments defined thereby. In  FIGS. 5 and 6 , the etched surface  211  in the bottom surface of the die pad  210  is indicated by the condensed hatching which slopes downwardly from right to left. 
     As will be also discussed in more detail below, in the fabrication process for the semiconductor device  1200  including the leadfame  200 , a semiconductor die is attached to the top surface of the die pad  210  through the use of an adhesive layer, with an encapsulant material thereafter being applied to the semiconductor die and the leadframe  200  to form the package body of the semiconductor device  1200 . Advantageously, the etched surface  211  formed in the peripheral portion of the bottom surface of the die pad  210  as indicated above effectively increases the distance along which moisture must travel to reach the semiconductor die mounted to the top surface of the die pad  210 . As a result, such semiconductor die is safely protected against moisture in the completed semiconductor device  1200 . Additionally, the flow of encapsulant material over the etched surface  211  during the formation of the package body of the semiconductor device  1200  facilitates the creation of a mechanical interlock between the package body and the die pad  210 . 
     Integrally connected to the die pad  210  are a plurality of extension bars  212 . More particularly, the leadframe  200  includes four extension bars  212  which extend diagonally from respective ones of the four corner regions defined by the die pad  210 . The extension bars  212  are identically configured to each other, and extend diagonally outwardly at predetermined lengths from respective ones of the corner regions of the die pad  210 . Each of the extension bars  212  defines opposed, generally planar top and bottom surfaces which extend in generally co-planar relation to respective ones of the top and bottom surface of the die pad  210 . During the fabrication process for the semiconductor device  1200  including the leadframe  200 , the encapsulant material used to form the package body of the semiconductor device  1200  does not completely cover the extension bars  212 , thus allowing for the removal thereof in a manner which will be described in more detail below. 
     The leadframe  200  of the semiconductor device  1200  further comprises a plurality of connect bars  220  which define a plurality of lands  230 , and a plurality of corner connect bars  220   a  which define a plurality of corner lands  230   a . As best seen in  FIGS. 5 and 6 , the connect bars  220  are integrally connected to extend between the die pad  210  and a generally quadrangular outer frame or dambar (not shown) of the unsingulated leadframe  200  which circumvents the die pad  210 . The connect bars  220  are segregated into four (4) sets, with the majority of the connect bars  220  of each set extending between one of the peripheral edge segments of the die pad  210  and a corresponding one of the four peripheral edge segments of the surrounding outer frame or dambar. Of the connect bars  220  of each set, the two central or middle connect bars  220  each have a straight, generally linear configuration, with the remaining connect bars  220  of the same set each having a non-linear configuration. As further seen in  FIG. 5 , the two outmost pairs of the connect bars  220  of each set are not attached to a corresponding peripheral edge segment of the die pad  210 , but rather attached to respective ones of an adjacent pair of the extension bars  212 . 
     As seen in  FIGS. 5-8 , the connect bars  220  are not of uniform thickness. Rather, portions of the bottom surface of each of the connect bars  220  are subjected to a partial etching process (e.g., are half-etched) as results in each of the connect bars  220  (other than those which are attached to the extension bars  212 ) having two (2) regions which are of increased thickness in comparison to the remainder thereof. One of these increased thickness regions of these connect bars  220  defines a land  230  thereof, with the remaining increased thickness region defining a connector  221 . Those connect bars  220  which are attached to the extension bars  212  each have one (1) region which is of increased thickness in comparison to the remainder thereof; such increased thickness region also defining a land  230  thereof. 
     As seen in  FIGS. 7 and 8 , the generally planar top surfaces of the connect bars  220  extend in generally co-planar relation to the top surface of the die pad  210 . Additionally, the lands  230  of the connect bars  220  and distal surfaces defined by the connectors  212  thereof each extend in generally co-planar relation to the bottom surface of the die pad  210 . The etched surfaces defined by the connect bars  220  extend in generally co-planar relation to the etched surface  211  of the die pad  210 . As will be discussed in more detail below, during the fabrication process for the semiconductor device  1200  including the leadframe  200 , the connectors  221  of the connect bars  220  are removed from the leadframe  200 , along with the extension bars  212  and the dambar, to electrically isolate the connect bars  220  and the corner connect bars  220   a  from the die pad  210  and each other. As seen in  FIG. 8 , it is contemplated that the removal of the connectors  221  can be simplified by further subjecting a portion of the top surface of each of those connect bars  220  including the same to a partial etching process (e.g., a half-etched) as results in each of the connectors  221  having a notch  221   a  formed therein. The etching of the notch  221   a  into each connector  221  effectively reduces the original thickness thereof (equal to the full thickness of the connect bar  220 ) by approximately one-half. As will also be discussed in more detail below, the encapsulant material used to form the package body of the semiconductor device  200  effectively covers both the top surfaces and etched surfaces of the connect bars  220 , thus resulting in almost the entirety of each of the connect bars  220  being encapsulated by the package body, and only the lands  230  and thereof being exposed in the bottom surface of the package body. 
     The corner connect bars  220   a  of the leadframe  200  are integrally connected to and extend between the outer frame or dambar of the unsingulated leadframe  200 , and respective ones of the extension bars  212 . Each of the corner connect bars  220   a  has a non-linear configuration. Also, as seen in  FIG. 5 , the corner connect bars  220   a  are segregated into four (4) sets. More particularly, inner portions of the corner connect bars  220   a  of each set extend from a respective one of the extension bars  212  in spaced, side-by-side relation to each other, with outer portions of the corner connect bars  220   a  of the same set extending to corresponding ones of the four peripheral edge segments of the surrounding outer frame or dambar. 
     The corner connect bars  220   a  are also not of uniform thickness. Rather, portions of the bottom surface of each of the corner connect bars  220   a  are subjected to a partial etching process (e.g., are half-etched) as results in each of the corner connect bars  220   a  having one region which is of increased thickness in comparison to the remainder thereof. In each of the corner connect bars  220   a  of each set, this increased thickness region defines a corner land  230   a  thereof. As seen in  FIG. 5 , the corner land  230   a  defined by each of the corner connect bars  220   a  of each set is generally aligned with the lands  230  defined by a corresponding set of the connect bars  220 . 
     In the leadframe  200 , the generally planar top surfaces of the corner connect bars  220   a  extend in generally co-planar relation to the top surface of the die pad  210 . Additionally, the corner lands  230   a  of the corner connect bars  220   a  each extend in generally co-planar relation to the bottom surface of the die pad  110 . The etched surfaces defined by each corner connect bar  220   a  extend and generally co-planar relation to the etched surface  211  of the die pad  210 . As indicated and discussed in more detail below, during the fabrication process for the semiconductor device  1200  including the leadframe  200 , the removal of the dambar and the extension bars  212  from the leadframe  200  effectively electrically isolates the corner connect bars  220   a  from each other, and from the connect bars  220  and die pad  210 . Further, the encapsulant material used to form the package body of the semiconductor device  1200  effectively covers both the top surfaces and etched surfaces of the corner connect bars  220   a , thus resulting in almost the entirety of each of the corner connect bars  120   a  being encapsulated by the package body, and only the corner lands  230   a  thereof being exposed in the bottom surface of the package body. 
     As is most apparent from  FIG. 5 , due to the structural features of the leadframe  200  as described above, the lands  230  and corner lands  230   a  are arranged in a generally quadrangular pattern which circumvents the die pad  210 . Additionally, the lands  230  and corner lands  230   a , like the connect and corner connect bars  220 ,  220   a , are segregated into four (4) sets, with each such set extending along a respective one of the peripheral edge segments defined by die pad  210 . As indicated above, each of the corner lands  230   a  is aligned with a corresponding set of the lands  230 . 
     The leadframe  200  may be fabricated from a conventional metal material, such as copper, copper alloy, steel plated with copper, or a functional equivalent. However, those of ordinary skill in the art will recognize that the present invention is not limited to any particular material for the leadframe  200 . Additionally, the number of connect bars  220  shown in  FIG. 5  is for illustrative purposes only, and may be modified according to application field. Along these lines, the connect bars  220  may have designs or configurations varying from those shown in  FIG. 5  without departing from the spirit and scope of the present invention. Additionally, though the connect and corner connect bars  220 ,  220   a  are each shown as being segregated into four sets, it will be recognized that fewer sets thereof may be provided, and may be arranged along any combination of two or three of the peripheral sides or corners of the die pad  210 . It is further contemplated that the leadframe  200  may be fabricated through the implementation of a chemical etching process or alternatively a mechanical stamping process. 
     Referring now to  FIGS. 13-16 , the semiconductor device or package  1200  as fabricated to include the leadframe  200  is shown in detail. As will be recognized by those of ordinary skill in the art, in the completed semiconductor device  1200  shown in  FIGS. 13 ,  14  and  16 , the dambar, connectors  221  and extension bars  212  are each singulated or removed from the leadframe  200  to facilitate the electrical isolation of the various structural features of the leadframe  200  from each other. As indicated above, the dambar, connectors  221  and extension bars  212  are singulated in a manner wherein connect and corner connect bars  220 ,  220   a , and hence the lands and corner lands  230 ,  230   a , are electrically isolated from each other, and from the die pad  210 . 
     In the semiconductor device  1200 , a semiconductor die  240  is attached to the top surface of the die pad  210  through the use of an adhesive layer  241 . The semiconductor die  240  includes a plurality of bond pads  242  which are disposed on the top surface thereof opposite the bottom surface adhered to the adhesive layer  241 . The bond pads  242  are used to deliver and receive electrical signals. 
     The semiconductor device  1200  further comprises a plurality of conductive wires  250  which are used to electrically connect the bond pads  242  of the semiconductor die  240  to respective ones of the connect and corner connect bars  220 ,  220   a , and hence the lands and corner lands  230 ,  230   a . More particularly, as seen in  FIG. 15 , the wires  250  are extended to the top surfaces of respective ones of the connect and corner connect bars  220 ,  220   a . The conductive wires  250  may be fabricated from aluminum, copper, gold, silver, or a functional equivalent. However, those of ordinary skill in the art will recognize that the present invention is not limited to any particular material for the wires  250 . One or more conductive wires  250  may also be used to electrically connect one or more bond pads  242  of the semiconductor die  240  directly to the die pad  210 . 
     In the semiconductor device  1200 , the die pad  210 , the connect and corner connect bars  220 ,  220   a , the extension bars  212 , the semiconductor die  240  and the conductive wires  250  are at least partially encapsulated or covered by an encapsulant material which, upon hardening, forms the package body  260  of the semiconductor device  1200 . More particularly, the package body  260  covers the entirety of the die pad  210  (including the etched surface  211 ) except for the bottom surface thereof which is circumvented by the etched surface  211 . The package body  260  also covers the top and etched surfaces of the connect and corner connect bars  121 ,  122 ,  120   a , as well as portions of the side surfaces thereof. The package body  260  furthers covers the top and side surfaces of the extension bars  212 . However, the package body  260  does not cover those surfaces of the connect and corner connect bars  220 ,  220   a , which define the lands and corner lands  230 ,  230   a . As such, in the completed semiconductor device  1200 , the bottom surface of the die pad  210 , and the lands and corner lands  230 ,  230   a  are exposed in and substantially flush with a generally planar bottom surface  261  defined by the package body  160 . During the process of fabricating the semiconductor device  1200 , the dambar, portions of the connectors  221  of the connect bars  220  and portions of the extension bars  212  are also not covered by the package body  260  so that they may be removed from the leadframe  200 . 
     The process for fabricating the semiconductor device  1200  is substantially similar to the process described above in relation to the fabrication of the semiconductor device  1100 . However, in the fabrication process for the semiconductor device  1200 , the removal of the connectors  221  and the extension bars  212  is facilitated by the completion of an etching process. More particularly, it is contemplated that a photoresist may be applied to the bottom surface  261  of the package body  260 , and in particular on to the exposed bottom surface of the die pad  210  and to the lands and corner lands  230 ,  230   a . The photoresist is then patterned so as to facilitate the necessary exposure of those portions of the connectors  221  and extension bars  212  which are exposed in the bottom surface  261  of the package body  260 . A wet etching process is then performed as facilitates the removal of the connectors  221  and extension bars  212 , and thus the separation of the connect and corner connect bars  220 ,  220   a  from the die pad  210 . As previously explained, during the process of forming the leadframe  200 , the notches  221   a  may be etched into respective ones of the connectors  221  as effectively reduces the thickness thereof and simplifies the process of removing the same by the application of a suitable etchant thereto. As seen in  FIG. 14 , a trench or recess  260   a  may be formed in the bottom surface  261  of the package body  260  as an artifact of the etching process used to facilitate the removal of the connectors  221  and extension bars  212 . 
     In the last step of the fabrication process for the semiconductor device  1200 , the outer frame or dambar is trimmed or removed by cutting with a cutting tool so that the connect and corner connect bars  220 ,  220   a , and hence the lands and corner lands  230 ,  230   a , are electrically isolated from each other and from the die pad  210 . It is contemplated that the dambar will be positioned outside of the package body  260  to allow for the removal thereof from the leadframe  200 , and is removed by cutting the same with a dambar cutting tool. It is contemplated that the removal of the dambar may also result in distal, outer ends of the connect and corner connect bars  220 ,  220   a  being exposed in and substantially flush with a peripheral outer surface of the package body  260 . 
     In the semiconductor device  1200 , the structural attributes of the leadframe  200  allow the lengths of the conductive wires  250  extending between the bond pads  242  of the semiconductor die  240  and the connect and corner connect bars  220 ,  220   a  to be minimized, thereby reducing the complexity of and fabricating costs related to the semiconductor device  1200 . Further, the leadframe  200  is uniquely configured so that conventional tie bars which would otherwise extend diagonally from each of the four corners of the die pad  210  to the dambar are replaced with each set of the corner connect bars  220   a . The inclusion of the corner connect bars  220   a , and hence the corner lands  230   a  defined thereby, effectively increases the number of input/output terminals in the semiconductor device  1200 , with the structural attributes of the corner connect bars  220   a  allowing for the lengths of the conductive wires  250  extending thereto to be decreased or minimized, thereby reducing the complexity of and fabricating costs related to the semiconductor device  1200  as indicated above. 
     This disclosure provides exemplary embodiments of the present invention. The scope of the present invention is not limited by these exemplary embodiments. Numerous variations, whether explicitly provided for by the specification or implied by the specification, such as variations in structure, dimension, type of material and manufacturing process may be implemented by one of skill in the art in view of this disclosure.