in one embodiment of the invention , an integrated circuit package is disclosed . the package has solder ball connectors on its lower surface , like conventional bga packages . however , this package is produced using many features of lead - frame based packages . such a package utilizes at least four different elements to achieve various improvements over the art . first , a lead - frame is employed with perforated die attach pads that allow encapsulant material to more easily flow underneath the dice , thus preventing process problems such as voids in the encapsulant layer . the drive toward smaller package sizes has also yielded smaller contact pads for placing solder ball connectors . as reductions in contact pad area also reduce the strength with which solder balls adhere to the package , a second improvement involves square contact pads that retain the same metal - to - metal clearance as standard circular contact pads , but that have a greater surface area . in this manner , embodiments of the invention yield stronger and more reliable solder ball connectors that still satisfy the constraints imposed by smaller package designs . third , aspects of the invention allow for wire bonding directly to partially - etched areas of the lead - frame . current wire bond sites must often be supported by support posts , or other unetched portions of the lead - frame , that leave exposed conductive areas on the outer surface of the package . as these conductive areas risk compromising the performance of the ic , they must be masked or otherwise insulated when the package is used , adding undesirable process time and expense . wire bonding to an etched area , or an area otherwise unexposed after encapsulation , thus removes some of these undesired conductive areas . fourth , a novel process for fabricating the ic packages of the invention is described . fig1 a illustrates a diagrammatic top view of a lead - frame strip suitable for use in packaging integrated circuits according to embodiments of the present invention . a lead - frame 101 can be configured as a metallic structure with a number of panels 103 of device areas . as illustrated in the successively more detailed fig1 b – c , each panel 103 has a two dimensional array of device areas 105 , each configured for use in a single ic package , and each connected by fine tie bars 107 . during packaging , one or more semiconductor dice are affixed to each device area 105 , where they are then subjected to known wire bonding , encapsulation , and singulation processes , yielding individual ic packages . in order to facilitate these processes , each device area 105 has a number of leads 111 , each supported at one end by the tie bars 107 . in the illustrated embodiment , the leads 111 have contact posts 113 formed at the distal end of the lead . each post extends to the bottom surface of the lead - frame 101 to provide a conductive contact pad 216 at the bottom surface of the lead frame . the leads 111 are etched , half - etched , or otherwise thinned relative to the posts 113 , so as to provide electrical connection to the posts 113 without leaving exposed conductive areas on the bottom surface of the lead frame , which as will be explained below may be packaged in a manner so that it becomes co - planar the outer surface of the encapsulated package . fig2 illustrates cross - section a — a of fig1 c , after the lead - frame 101 has already been subjected to the die attach , wire bond , and encapsulation processes . the resulting ic package 200 has a semiconductor die 202 that is attached to the substrate 204 with an adhesive 206 . the package 200 also has bond wires 208 that electrically connect the die 202 to the bond sites 210 of the leads 212 . an encapsulant 214 , e . g ., a known molding material , surrounds the die 202 and substrate 204 , leaving only exposed contact pads 216 ( which are simply the lower surfaces of the posts 113 ) at the bottom surface 218 of the package . the package 200 is shown after encapsulation , but prior to singulation . in practice then , electrical connectors such as solder balls are attached to the contact pads 216 ( often , but not necessarily , after plating or cleaning the pads 216 to inhibit / remove oxidation ), and the lead - frame 101 is singulated ( commonly sawed ) along its tie bars 107 , to cut away each individual package 200 . in this manner , a novel package is fabricated , in which a “ micro - array ” of solder connectors exist on the bottom surface 218 , allowing the package 200 to be used as a bga - type package , yet employing lead - frame based fabrication techniques for ease and efficiency of manufacture . the resulting “ micro - array ” package thus offers many advantages inherent in both bga - type packages and qfn - type packages . to facilitate manufacture of these micro - array packages 200 , a number of novel features may be employed , several of which are discussed below in further detail . as discussed briefly above , a die 202 is attached to a die attach region of the lead - frame where it overlaps die attach structure 109 and possibly portions of some of the leads 111 . after the die is adhesively secured to the lead - frame , it is wirebonded and encapsulated with a molding material 214 . however , during encapsulation , liquefied molding material 214 must flow under and around all the various structures of the device area 105 , or else voids may form in the encapsulant 214 . such voids risk leaving exposed electrically conductive areas on the outer surface of the package 200 that leave the package 200 vulnerable to electrical shorts or other forms of damage . in order to help alleviate this problem , the lead - frame 101 of fig1 c includes the die support structure 109 . more specifically , the die support structure 109 is configured not as a single rectangular die attach pad - like structure , as might be used in various other packaging styles , but rather as a lattice - like structure capable of supporting a die 202 while allowing sufficient space for encapsulant material to flow therethrough . for example , in fig1 c , the die support structure 109 is made up of an array of posts 113 interconnected by struts 115 , or support risers , that provide structural stability while still allowing flow of the molding material . in essence , the struts 115 are portions of the lead - frame 101 that have been half - etched ( or subjected to any other process by which material can be removed from the lead - frame 101 ) like the leads 111 , so as to leave space between the bottom surface 218 and the strut 115 . in this manner , encapsulant material can flow under the die 202 and through the open areas 119 in the lead - frame 101 , as well as under the struts 115 themselves . the struts 115 thus provide a lattice - like structure that leaves open areas 119 which span the full height of the lead - frame 101 . this allows encapsulant to flow through a larger area than would be possible if the bottom surface of a large rectangular die attach pad was etched to define a number of posts 113 , which would lack such full - height open areas 119 . one of skill will observe that the generally “ swastika - shaped ” appearance of the die support structure 109 creates four open areas 119 for encapsulant to flow through relatively unimpeded . additionally , the half - etched struts 115 provide space underneath them , further facilitating encapsulant flow under the die 202 . in the embodiment illustrated in fig1 c , the die support structure also includes a plurality of support bars 118 that carry the die support structure 109 and pads 117 . in the illustrated embodiment , the pads 117 appear as enlarged legs of the “ swastika - shaped ” die support structure . like the struts 115 and leads 111 , the pads 117 and support bars 118 are partially etched from the bottom surface so that they are not exposed at the bottom surface of the lead - frame . the illustrated pad structure has a number of advantages including providing additional structural stability for the die support structure and when the die is not significantly larger than the die support structure , they may also serve as wirebonding surfaces that facilitate downbonding from the die to the die support structure 112 . as will be appreciated by those familiar with packaging generally , it is sometimes desirable to make an exposed die attach pad a ground ( or power ) plane . in the illustrated embodiment , the die support structure 109 may be configured as a ground ( or power ) plane simply by downbonding to the pads 117 and / or the support bars 118 . one of skill will also observe that the various lead - frame configurations of the invention need not be limited to the swastika like shape of fig1 c . rather , a wide variety of die support structures may be used to facilitate the flow of encapsulant material underneath the die 202 . for example , fig3 illustrates a die support structure 109 with a generally “ snowflake - shaped ” configuration in which the posts 114 are interconnected by half - etched struts 115 arranged as shown . such an arrangement helps create open areas 119 that channel flow of encapsulant toward the center of the die support structure 109 , an area where voids are often most likely to be formed . as in the swastika - shaped configuration ( and indeed , many other possible configurations ), pads 117 can be provided to allow for downbonding and increased structural stability of the lead - frame 101 , while still allowing encapsulant to flow underneath . in the illustrated embodiments , a unitary die support structure is provided , wherein all of the struts are electrically connected . in other embodiments , the die support structure may be divided into two or more components . such an approach can be particularly useful in situations where it is desirable to provide multiple independent ground / power planes . referring next to fig4 and 5 , some other embodiments will be described that utilize non - circular contact pads on the contact posts . in the embodiment illustrated in fig4 a and 4b , the contact pads have a substantially square footprint , instead of the substantially circular footprint illustrated in fig1 c . with reference to fig1 c again , note that a certain metal - to - metal clearance h must be maintained in order to prevent electrical interference between leads 111 and adjacent posts 113 . one commonly used rule states that h must be approximately equal to or greater than half the height of the contact posts . thus , for 0 . 5 mm thick lead frames , h must be maintained at least at 0 . 25 mm . the exact numerical value for the clearance h varies , and is not central to the invention , but does typically impose a design constraint : the cross - sectional area of the posts 113 ( i . e ., the contact pad size ) must be sufficiently small that the distance h between the posts 113 and adjacent leads 111 is always maintained . however , reducing contact pad size also reduces the strength with which solder connectors adhere to their contact pads . as a solution to this dilemma , embodiments of the invention employ generally noncircular contact pads whose shapes allow for increased surface area relative to circular contact pads , yet maintain the same metal - to - metal clearance as conventional circular contact pads . as one example , fig4 a illustrates a bottom view of a device area 301 of a lead - frame 101 , in which the posts 113 are fabricated with generally square cross - sections . these square cross - sections yield generally square contact pads 303 that have greater cross - sectional areas than equivalent circular contact pads . fig4 b illustrates this concept in greater detail . note that , in order to maintain a minimum metal - to - metal clearance h between a contact pad 303 and its adjacent lead 115 without excessively thinning the lead 115 ( which poses many known problems ), a circular contact pad 303 can at maximum have a diameter d , as shown . however , one can observe that a square contact pad 303 with sides of length d offers greater surface area than the circular contact pad , while maintaining the same metal - to - metal clearance h . this increased surface area increases the size of , and thus improves the shear strength and reliability of , the solder joint . consequently , such an increase in surface area relative to circular pads allows for stronger and more reliable connections between the contact pads and their solder connectors , such as solder balls . it should be noted that the use of noncircular contact pads does not affect the fabrication of ic packages 200 . that is , packages employing square contact pads 303 may be fabricated in the same manner as described above ( and further explained below ). it should also be noted that while fig4 a – b employ generally square contact pads 303 , the invention need not be so limited . rather , the invention contemplates the use of any shape contact pad 303 that is designed to offer increased surface area relative to a circular contact pad having the same minor axis dimension , and that maintains or increases the corresponding metal - to - metal clearance h . for example , fig5 illustrates a lead - frame 101 employing oblong posts 113 whose bottom surfaces provide oblong - shaped contact pads 303 . more specifically , if the width ( minor axis dimension ) of the oblong pads 303 is maintained as d while the height , or longitudinal direction ( major axis dimension ), is increased to a length sufficiently greater than d , the oblong pad 303 can offer greater surface area than a circular contact pad 303 with diameter d . furthermore , this can be done while the metal - to - metal clearance is maintained at h . further embodiments of the invention allow for generally square contact pads that have sides of length d , yet offer similar surface area than even a circular contact pad with diameter greater than d . for instance , is known that generally circular contact pads having diameters of 0 . 25 mm yield acceptable solder connector strength and reliability . the ability to manufacture posts 113 having a diameter of 0 . 225 mm is also known and is desirable , yet yields weaker and less reliable solder connectors . consequently , embodiments of the invention include use of generally square contact pads 303 that have sides of length 0 . 225 mm , thus offering the same metal - to - metal clearance as circular pads of diameter 0 . 225 mm , yet having greater surface areas . more specifically , by sufficiently reducing the amount that the corners of the square contact pad 303 are rounded ( in this example , limiting the corner radius to a maximum of 0 . 05 mm ), one of skill can see that a generally square contact pad 303 having sides of length 0 . 225 mm can achieve 99 % of the surface area of even a 0 . 25 mm circular contact pad . yet another aspect of embodiments of the invention involves wire bonding to an etched or otherwise thinned portion of the lead - frame 101 . for example , fig2 illustrates bond wires 208 that have been wirebonded directly to half - etched bond sites 210 of leads 212 . conventional bond sites must be directly supported . that is , the lead - frame 101 must have an unetched portion that extends to the bottom surface 218 in the area directly beneath the wire bond , or some other form of support for the bond site 210 . otherwise , conventional bond sites are unable to support the stresses of wire bonding operations without flexing or bowing excessively , or simply giving way entirely . one approach to supporting the bond site 210 involves filling the area underneath the bond site 210 with encapsulant material prior to wire bonding , as is explained in the co - pending u . s . patent application ser . no . 10 / 650 , 325 to bayan et al ., which is hereby incorporated by reference in its entirety and for all purposes . another approach , taken in embodiments of the present invention , involves the cumulative effect of various improvements to a lead - frame 101 and its associated structures . by way of example , one described embodiments of the invention employs three features that work together to make is practically possible to wire bond directly to half - etched ( or otherwise thinned ) bond sites 210 : 1 ) a harder lead - frame material is employed , 2 ) a stronger support tape is used , and 3 ) various structural features are incorporated into the lead - frame 101 itself . with regard to the material of the lead - frame 101 , current lead - frames are often made of alloys too weak to support wirebonding when their leads 212 are thinned . commonly , it is well known that such alloys exhibit excessive bowing or other deformation when subjected to wirebonding , thus producing poor wire bonds . for example , known alloys such as c194 copper alloy from olin corp . are of insufficient hardness to support wirebonding on half - etched areas of many lead - frames made from it . however , it has been found that materials with vickers hardnesses of at least 160 to 195 ( which is in the range of at least approximately 35 % to 50 % greater than the hardness of c194 ) are sufficiently hard to withstand wirebonding on half - etched areas of a 6 mil thick lead - frame when employed along with other described features . such harder materials are known , and include alloys such as c7025 from olin corp ., as well as eftec 64t from the furukawa electric co ., ltd . the invention is , however , not limited to the use of these specific alloys . rather , it contemplates use of any lead - frame material of sufficient hardness to withstand , alone or in combination with other features of the invention , wirebonding operations on leads made from the material and thinned to a thickness of less than the thickness of the lead - frame . as to the support tape , current fabrication processes often employ an adhesive tape backing attached to the bottom surface 218 to further reinforce the lead - frame 101 during wirebonding . however , many current adhesive tapes adhere to the lead - frame 101 with insufficient strength , allowing for excessive bowing of the leads 212 at the bond sites 210 , and absorbing too much energy during wirebonding , thus yielding poor wire bonds . it has been found that adhesive tapes employing thermoplastic adhesives , that have greater adhesive properties than current lead - frame tapes , secure the lead - frame 101 and absorb reduced amounts of energy during wirebonding , so as to facilitate wirebonding on thinned leads 212 . for example , rt321 produced by hitachi , ltd . has been found to yield satisfactory wire bonds when employed in conjunction with other features of the invention . as with the lead - frame material , the invention is of course not limited to the use of specific tapes . rather , it contemplates use of any tape having sufficient adhesive properties to allow , alone or in combination with other features of the invention , wirebonding operations on leads that are thinned to a thickness of less than the thickness of the lead - frame . fig6 a – d illustrate some such structural features employed in an embodiment of the invention to help facilitate direct wirebonding to a thinned lead . first , recall that tie bars 107 are employed to connect adjacent device areas 105 , as described above . commonly , these tie bars 107 are simply straight sections of the lead - frame 101 . often , the tie bars are thinned like the leads in order to reduce the amount of material that must be cut through during singulation . however , longitudinal ribs 402 and lateral ribs 400 can be added underneath the tie bar 107 . the lateral ribs 400 are placed adjacent to leads 212 , and extend toward the bond sites 210 of the leads 212 so as to provide extra support for the bond sites 210 . such ribs 400 can also be placed at the opposite end of the lead 212 , so as to provide additional support from the other end of the bond site 210 as well . in certain embodiments , it is preferable to configure the ribs 400 , 401 with saw singulation in mind . more specifically , when the tie bars 107 are cut away during singulation , it is often preferable to cut away the rib supports as well , so as to minimize the amount of conductive surface exposed at the outer surface of the ic package . thus , as shown in fig6 c for singulation by a saw blade of width w , the lateral ribs 400 can be configured to extend less than w / 2 distance from the centerline of the tie bar 107 toward the bond site 210 , so that the entirety of the lateral rib 400 is cut away by the saw blade . the longitudinal ribs 401 are intended to extend along the length of the tie bars . it should be noted that the presence of ribs 400 , 401 adds material that must be sawed away during singulation . this extra material contributes to many process inefficiencies , such as reduced saw blade life , longer process time as more material must be cut away , etc . to help alleviate these issues , the longitudinal ribs are designed to be significantly narrower than the tie bars themselves . in other embodiments , additional material can be removed from the tie bars 107 . for example , material along the centerline 404 of the tie bar can be etched away or otherwise removed , with thin connectors left connecting adjacent ribs 400 . in other words , adjacent ribs can be kept as single solid structures , connected only to each other . the invention includes any such configuration in which material is removed from the tie bars 107 to facilitate saw singulation without excessively compromising the structural integrity of the lead - frame 101 . leads 111 themselves can also be designed to assist in wirebonding to their half - etched portions . more specifically , the leads 111 in the lead portion 402 of the device area 105 are oriented generally in a “ fan ” configuration with the major axis of each lead 111 oriented toward the geometric center of the device area 105 . in this fashion , one of skill can see that more wirebonding loads are directed axially , where the leads 111 are stronger , rather than in a transverse direction , where they are weaker . a method of fabricating ic packages 200 is now described . fig7 illustrates process steps taken in the fabrication of such packages 200 . many of the individual steps shown are not in themselves novel . however , the particular combination of process steps is believed to be novel . the process begins with a semiconductor wafer , which is a standard configuration for fabricated ics prior to dicing . a film adhesive such as a known b - stage adhesive is applied to the back side of the wafer ( step 500 ), and the wafer is then diced ( step 502 ). dicing the wafer after application of the adhesive allows for application of the adhesive in a single operation and to a single body — the wafer — rather than in multiple operations to many individual ic dice . for b - stage adhesives or other adhesives that require heating prior to die attach , the dice are heated to the appropriate temperature and then attached to the die attach regions 109 of the device areas 105 ( step 504 ). if necessary , the adhesive is then cured ( step 506 ). once the curing process is complete , the dice are wire bonded to the appropriate bond sites ( step 508 ) and the lead - frame 101 is encapsulated ( step 510 ), de - taped ( step 512 ), and cured to harden the molding material ( step 514 ). once the lead - frame 101 is encapsulated , serial numbers or other identification numbers can be imprinted on the outer surface of the encapsulation material ( step 516 ), and the solder balls or other connectors can be attached . recall that , as the package 200 is a bga - type package from an external point of view , contact pads remain exposed on the underside of the package 200 . if solder - based connectors are employed , any oxidation is first cleaned from the contact pads 303 ( step 518 ). the surfaces of the contact pads 303 are then treated appropriately , such as by application of ni — au plating if desired , or in some embodiments , simple cleaning with no other application of material to the pads 303 . solder connectors are then attached to the contact pads 303 , such as by known reflow or ball attach processes ( step 520 ). the individual packages can then be saw singulated ( step 522 ), where they are then ready for inspection and / or testing ( step 524 ). the foregoing description , for purposes of explanation , used specific nomenclature to provide a thorough understanding of the invention . however , it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention . thus , the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description . they are not intended to be exhaustive or to limit the invention to the precise forms disclosed . it will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings . for example , although a number of significant features of the illustrated micro - array packages have been described , it should be appreciated that the different features do not need to be used together . rather , many of the described features may be employed individually or in subcombinations in different micro - array lead frame packages . in the illustrated packages , the contact posts 113 were generally illustrated at the distal end of the leads 111 and most of the leads had a single contact post . however , these are not requirements . rather , each lead can interconnect multiple contact posts 113 , and vice versa . with respect to the described die attach structure feature , the struts need not be limited to swastika - shaped , or snowflake - shaped , configurations , but rather can assume any configuration that facilitates flow of the encapsulant material under the die and that prevents voids . likewise , the leads of the die attach regions can be made of any lead - frame compatible material that is of sufficient hardness to facilitate wirebonding on their half - etched , or otherwise thinned , portions . additionally , the contact pads can be generally square , generally oblong , or any non - circular shape that affords relatively greater surface area while maintaining appropriate metal - to - metal clearances . the embodiments were chosen and described in order to best explain the principles of the invention and its practical applications , to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated . it is intended that the scope of the invention be defined by the following claims and their equivalents .