CA1238428A - Thermally enhanced integrated circuit carrier package - Google Patents
Thermally enhanced integrated circuit carrier packageInfo
- Publication number
- CA1238428A CA1238428A CA000545109A CA545109A CA1238428A CA 1238428 A CA1238428 A CA 1238428A CA 000545109 A CA000545109 A CA 000545109A CA 545109 A CA545109 A CA 545109A CA 1238428 A CA1238428 A CA 1238428A
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- 239000000463 material Substances 0.000 claims abstract description 26
- 239000004065 semiconductor Substances 0.000 claims abstract description 11
- 238000000576 coating method Methods 0.000 claims description 21
- 230000004927 fusion Effects 0.000 claims description 12
- 238000012546 transfer Methods 0.000 claims description 8
- 239000000853 adhesive Substances 0.000 claims description 6
- 230000001070 adhesive effect Effects 0.000 claims description 6
- 230000008021 deposition Effects 0.000 claims description 6
- 239000004020 conductor Substances 0.000 claims description 5
- 238000007499 fusion processing Methods 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 4
- 230000007613 environmental effect Effects 0.000 claims description 3
- 239000012811 non-conductive material Substances 0.000 claims 2
- 230000035515 penetration Effects 0.000 claims 2
- 239000012876 carrier material Substances 0.000 claims 1
- 230000002708 enhancing effect Effects 0.000 claims 1
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- 230000004907 flux Effects 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 28
- 239000011248 coating agent Substances 0.000 description 14
- 238000012856 packing Methods 0.000 description 13
- 230000008569 process Effects 0.000 description 9
- 150000002500 ions Chemical class 0.000 description 5
- 238000007500 overflow downdraw method Methods 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 229920003023 plastic Polymers 0.000 description 4
- 238000007747 plating Methods 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 238000005276 aerator Methods 0.000 description 2
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- 150000002739 metals Chemical class 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 241001270131 Agaricus moelleri Species 0.000 description 1
- 241000282320 Panthera leo Species 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
- H01L23/367—Cooling facilitated by shape of device
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4803—Insulating or insulated parts, e.g. mountings, containers, diamond heatsinks
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
- H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
- H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
- H01L23/3733—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
THERMALLY ENHANCED INTEGRATED CIRCUIT
CARRIER PACKAGE
ABSTRACT
An integrated circuit carrier package complimented with a mass of highly conductive spherical bodies fused into a semi-random porous lattice matrix. Such component thus resembling a heatsink with generally fin-like structures that are generally arranged diagonally about the base carrier and coated with material(s) which enhance thermal radiation discharge to the surroundings. The carrier package with said intrinsic heatsink thus transmits substantial heat fluxes away from the semiconductor material for enhanced operational domains.
CARRIER PACKAGE
ABSTRACT
An integrated circuit carrier package complimented with a mass of highly conductive spherical bodies fused into a semi-random porous lattice matrix. Such component thus resembling a heatsink with generally fin-like structures that are generally arranged diagonally about the base carrier and coated with material(s) which enhance thermal radiation discharge to the surroundings. The carrier package with said intrinsic heatsink thus transmits substantial heat fluxes away from the semiconductor material for enhanced operational domains.
Description
TORY IVY Fly NCF~I) INTF.(~RATFD (IRRUPT
ROUGH P.~(~KA.F.
The objccllvc Or this in~cnlion is to implcmcn~ a lo~v-mass high-cfricicncy heat sink directly into the carrier pacl;agc.Bydoingso,asemiconductorcircuit(s)willopcccrateatalowertcmpcraturethanitwouldinexistingf.attccarrier package. The lower die ~cmpcrature results in heightened reliability of the circuit(s) and improved performance.
The invention increases the thermal capability of the integrated circuit carrier package by directly integrating a heat sink into it. This is accomplished by the addition of a thermal structure comprised of generally spherical units fused in a preferably porous and scmi-random nature. The spherical units are composed of such highly thermally conductive materials as ceramics, plastics, metals etc. The resulting structure generates a geometry with minimal weight, large surface area, and thermally enhanced conductive, convective and radiative properties. The physical structure undergoes thermal conduction through the material producing temperature gradients in said. By controlling the fusion process, thermal conductivity at the spherical contact points can be varied by exploitation of contact resistances. Fusion of these bodies into shape or form provides mechanically adw~mtageous properties of strength and thermal conductivity. The large surface ares generated by use of many such spherical units, enhance convection and radiation transfer.
The structure formed is generally coated with material(s) with properties of being highly remissive and selectively absorptive and reflective. Whereas thermal radiation is emitted at free surfaces to the environmental surroundings, emissions within the core of said structure are absorbed by cooler portions and reflected by others to produce temperature gradients. The addition of a surface coating(s) provides a mechanism to control this discharge process accordingly. Since thermal radiation transfer is fourth-degree temperature dependent, large fluxes are readily transferred both internal and external to the structure. Coatings of a highly remissive nature will emit thermal radiation readily. Internal emissions can also be selectively absorbed, reflected or both depending on the electromagnetic energy of the infrared photons and the properties of said coating(s).
Spherical units are used for several reasons. Uniform spheres will generally pack themselves into a symmetrical matrix, generate trivial contact areas, and radiate in a spherical nature. Packing such spheres into a shape or form can be readily controlled. Given the special dimensions of such shape or form, the dimension of the required spherical can be readily determined depending on the matrix density required. Specifically, the minimal dimension of the required special is considered the principal packing size vector. This principal packing vector is divided by an irrational fraction composed of an integer specifier raised to an arbitrary power and divided by another arbitrary number. The integer specifier is a count of the number of adjacent spheres along the peeking vector. Use of this peeking technique results in oversized spherieals which produce dimensional remainders on the peeking vector. This concept can be used to control matrix packing accordingly.
The invention is generally complimented by open channels arranged within said. Inclusion of open channels in a design facilitates the flow characteristics of said device. Forced flow across the principal axis becomes generally turbulent upon encountering diagonally arr~mged flow channels. Cross flow is readily generated through the actual spherical structure. The physical nature of said structure promotes generally turbulent inner flow. When said structure Lo is in ho prcscncc Or a ~vorl;ing Rowley in sucker static or dynamic silna~ions, thermal convection will occur. As an added bcnirn~ snip channels alto increase ho vice factor for mediation cxchan~c lo the surrounding surfaces.
The physical aspects of the invention such as porosity, fusion boundaries, open flow channels, coating(s) etc.
arcintrinsic~olhcpcrformanccof~hcdcvicc.Thcscparammmetersmustbeconsideredconcurrentlyinordertoimplemmoon the apparatus described. lattice structure and porosity directly affect convective heat transfer characteristics as does the channclling. Porosity is directly related to fusion boundaries and coating(s) thickness. Conductivity of the structure to heat is affected by fusion boundaries and spheroid material, The relations continue on, and must be summarily considered.
Manufacture of said invention begins with the spherical units as the raw component. Since geometrically perfect spheres are not necessitated ( to. as in precision ball bearings ), generally spherical elements may be utilized since they are readily produced in cost-effective quantities utilizing current techniques. Dimensionally, they would be in the range of O.5mm to 2.0mm with the only constraint being some form of statistical uniformity over a given sample.
Actual form of the invention is obtained by fusion of the spherical in combination with a die. Process descriptions of the related art can be found in US Patent #3,825,064. Straight forward die design techniques are employed for this implementation. Generally however, tapered die walls may be employed for enhallccd force distribution and easier removal of the finished structure. These die walls may also have an incremental ripple pattern to assist in forming more consistent fused structures by identically locating the spheroids. Loading of Lye die with the raw component can be enhanced with oscillation of the die to vibrate the spheres into their optimum position and an angular offset to the orientation of the die. This in combination with moderate die pressures will produce more Consistent structures. Die pressure is an important factor to control the contact resistances of the structure and hence the specific conductivity of said. These factors are optimized with regard to the maximum compressive strength of the spherical. The fused structure may then be machined flat and a thin plate of identical material fused to this area.
The thermal resistance of the invention is composed of a convective term and a conductive term. The contact resistanceduringthefusionprocessdirectlyaffectsthiiislatterterm.ltisafunctionofthewelddynamicsandtheesspheroid material. Acknowledging this, an exploitation of material sciences can be made. Here, spheroids of a highly conductive material such as aluminum are coated with a thin surface of silver. During the fusion process, the weld locations would become alloyed into a material with a slightly higher conductivity than the parent spheroids. The remaining silver surface could be reclaimed by an etching process prescribed later. Application of this technique yields a lower thermal resistance while maintaining constraints such as cost and mass within acceptable domains.
Various fusion techniques exist to complete tune formation process. Resisdve-type heating is effective for many different materials. Plasma-lype fusion methods employing large voltages can be used where material dissimilarity is present such as metal to ceramic bonding. For materials such as plastics, utilization of techniques employing sonic-welding will prove effective. The above-mentioned techniques may be used separately or in hybrid combination to effect the production of the invention.
The fusion process may cause the spheroid mass to lose some of its porosity. This can occur from excessive clilml-in~ pressures. or I Of- the clcc~rical/lllatcrial cffccls inhcircm Jo the process. A method lo reclaim this porosity Lucille is necessary for cnllanccd convcc~ivc flow of the invcn~ion, is corrosive surface etching. Here the spheroid structure is placed in a corrosive (to the malarial) bath. The conccn~ralion of Iris solution is appropriate to the desired etch spccifica~ion. Such an etching technique may generally reclaim some lost surface areas and open the interstitial spaces of the structure. This technique can also serve as a precursor to the coating(s) deposition step. Here, the surfaces of the structure are etched by a dimension that is equal lo the coating thickness to be applied later. Utilization of this technique optimizes surface area, porosity, and coating(s) deposition simultaneously.
The need lo coal Ike resulting structure with a highly em missive surface gives the invention its special ability of radiative heat transfer. The basic material of the spherical may have varying degrees of surface em missive coefficients, The optimum configuration would be black body behavior, but several materials exist that approach this level. Multiple and dissimilar coatings may also be utilized to produce surface characteristics of unique abilities. This concept is similar in nature to conductor deposition on a semiconductor material to produce logic gates. In such an implementation, the electromagnetic nature of such a surface could be highly em missive and selectively reflective or absorptive for a given energy band. The permutations of available surfaces produces a domain of such unique surfaces.
Actual deposition of the coating onto the structure may proceed in bicycle two manners. The st~mdard process of electrochemical plating may be employed for materials which are readily applied by said. Since the structure of the invention is such that small voids exist, the possibility of the plating process encompassing these voids is present. To maintain a porous structure with a uniform coating, it is advisable to have the electrochemical fluid in ntrbulent my fluctuating flow about the invention. This will result in a fluid with more consistent ion distribution for uniform plating and at the same time maintaining the geometry of the invention. The actual implementation of this concept would include the use or application of a randomly vibrating holding jig and/or an aerator bubbling system. A second method of coating deposition relies on plasma discharge. Many materials require only a highly oxidized slLrface for a high emmissivecoefficient.Thiscanbeaccomplishe(lbypassiiingaplasmastreamthroughandabouttheillventiontooxiiodize the material. Plasma coating can be extended lo deposit such materials as metals and ceramics. Careful attention to thedynamicsoftheplasmastreamisnecessary~oproduceunnniformcoatinginsuchacomplexstructureasthisinYentiloon.
By far, Ike most crucial and complex step in achieving the invention relies on coating selection and application.
Features, objects, and concepts of this invention are more readily understood symbolically trough the aid of a drawing, specifically:
Fly&. 1 is an isometric view of a Pin Grid Array (PEA) carrier package incorporating tune above-described invention's concept;
FIX&. I is an exploded cross-sectional view of a PEA carrier package showing Ike major components and details of the invention;
FIG. I is an exploded side-view of a thermal retrofit assembly;
I IT. I is a Topeka illusua~ing ho diagonal flow characteristics of ho invention;
FIG. I is a magnitl~d scgmcn~ illus~raling hl~crnal low characteristics of Ike inhalation;
FIG. 4 is an illuslra~ion depicting ho concept of controlling the compact resistances;
FIG. 5 is a schematic depicting the natural modes of heat-transfer including convection conduction radiation and internal modes of emission reflection and absorption;
FIG. I is an illustration of an example special volume with the selected packing vector;
FIG. I is an illustration of the packing concept with No FIG. I is an illustration of the packing concept with No FIG. I is an illustration of the packing concept with No FIG. I is an illustration of the packing concept with No FIG. I is a magnified top-section illustrating the rippled die walls;
FIG. I is an isometric view of an angularly offset die;
FIG. I is a schematic illustrating resistive-heating fusion method;
FIG. I is a schematic illustrating plasma-type fusion method;
FIG. I is a schematic illustrating sonic-welding fusion method;
FIG. I is an illustration of an electrochemical plating method;
FIG. I is an illustration of a plasma coating process.
A better understanding of the invention is made by specific reference to the drawings. The implementation of the invention and its concepts are readily made in various forms. In FIGURE I the heat sink 1 has a machined flat underside 2 which is fused to an intermediate plate 3 of generally identical material. This is to facilitate a substructure with uniform thermal expansion abilities which will not induce excessive stresses on the rest of the carrier package. A thermally conductive and elastic adhesive 4 typically mates the above assembly to an isolation platform 5 of high thermal conductivity but electrically insulated. Signal traces 6 wire bonds 7 and the semiconductor circuit(s) X are affixed to 5 allowing the electrical signal network to be established. This assemblage is further affixed to an electrically inert base carrier 9 with a contact pin gild array 10. The semiconductor circuit(s) S subsequently occupies theherrneti~llysealedcharnberllacccssedbycoverplatttel2.Asaretrofitdevice FlGURE2(b)illustratestheheatsink 1 with a flat underside affixed by adhesive 4 to an existing flat-top integrated circuit package 13.
The invention operates well in static air-flow situations but has improved operational characteristics in a dynamic convective air-flow. In Figure I the diagonally arranged fin-like structures Id. are illustrated with a Lo furiously Lowe vector nomlal lo at side of the pacl;agc. Upon cncounlcring ho pickax a channel tow vector 15 is established which cvcmually becomes ~urbulcnl. Synch turbulent action is further visualized in FIGURE I. Here, a substantially reduced surface flow 16 is imcrmixed with turbulent inner tows 17. This compounding turbulent affect enhances convcc~ivc heat transfer dramatically. This implementation of the invention also frees the electronic designer fromcomplicatedpans-to-floworientationoncircuitboaaardsetc.Thecarrierpackageisihuspartiallyomni-direecctional to forced flow since a turbulent convective intermix is achieved when generally normal vectored flow encounters the invention.
Spheroids are utilized in this invention because they maximize surface area and minimize mass. When implemented in this invention, some important aspects must be considered. In FIGURE 4, an illustration of fusion boundariesl8,clampingforcesl9,and~hethcrmalresistaaance20ismade,Thisisanimportantconceptoftheinventiloon which must be optimized for each implementation. The clamping force directly affects the dimension of the fusion boundaries. A too large a force will greatly reduce the surface areas generated by the spheroids, and reduce the porosity of the fused structure. This will directly affect the operation of the invention. The thermal resistance is also directly related to this consequence. The greater the cross-sectional area at the fusion boundary, the less thermal resistance of the structure to heat flow is enacted. The fused spheroid structure will have more thermal resistmce than its parent material, but with a highly conductive material it is intended that an optimized resistance will be implemented understanding the above constraints. The available modes of heat transfer are illustrated in FIGURE 5. The three main modes of convection 21, radiation 22, and conduction 23 supplemented by intemal emissions 24, reflections 25, My adsorptions 26. The nature of these modes and their effect on the invention have been previously detailed above, but it must be stressed that all are inter-related and must be optimized as such.
The porosity and arrangement of the spheroid matrix can be controlled Vito the packing vector concept outlined previous. This is graphically illustrated in FIGURE I with the selected packing vector 27. FIGURES I-(e) illustrate in two dimensions the structures formed when the size of the spheroids and the packing count is changed.
The concept is more readily understood visually, and indeed confirmed about its viability. Packing the spheroids in a desired matrix form consistently is filrther accomplished by enhancements to the fusion die. In FIGURE I, a top sectional view of the rippled die wall 28 illustrates an enhancement for uniform consistency from unit to unit. The spheroids 29 will generally arrange themselves better when ( in FIGURE I ) the die 30 is angularly offset 31 and vibrated during loading. The frequency of die vibration must be such that the individual spheroids are displaced into the more lmiform arrangement. Although these methods and concepts are not 100% effective, some consistency can still be invoked by utilization of said.
Tune principles of spheroid fusion are well know, but are illustrated in FIGURES I- . In I, the resistive heating or electric current method is depicted. This method is typically used as a preheat phase in sophisticated processes. Passing a current through a conductive spheroid mass will heat and fuse them together. A voltage discharge method as in I can also fuse spheroids together with less dimensional distortion then the above method and with the added benefit of placing an oxidized surface coating on the structure. A sonic-welding technique I is also applicable to more malleable materials such as plastic. The heat sink portion of the invention could possibly be :~3~3~
manufactllred out of plastic with high thermal conductivity with Ike binaural of minimal weight The coating processes are illustrated in FIGURES I,. In I, an electrochemical playing tank 32 is enhanced with an aerator stem 33. This in combination with an oscillating work-holding jig 34 plates a surface coating on the heat sink 1 in a turbulent fashion. Such turbulent action maintains the integrity of the porous matrix structure.
Some coatings are better applied utilizing a plasma discharge process as in FIGURE I. Here surface oxidization, or reduction reactions can be implemented on the heat sink 1 or other materials deposited upon the surface through plasma jets35.Atypicalinstallationofsuchaprocesswouldincllludeanevacuatedchamber36,aholding jig37,anddeflection magnets US.
ROUGH P.~(~KA.F.
The objccllvc Or this in~cnlion is to implcmcn~ a lo~v-mass high-cfricicncy heat sink directly into the carrier pacl;agc.Bydoingso,asemiconductorcircuit(s)willopcccrateatalowertcmpcraturethanitwouldinexistingf.attccarrier package. The lower die ~cmpcrature results in heightened reliability of the circuit(s) and improved performance.
The invention increases the thermal capability of the integrated circuit carrier package by directly integrating a heat sink into it. This is accomplished by the addition of a thermal structure comprised of generally spherical units fused in a preferably porous and scmi-random nature. The spherical units are composed of such highly thermally conductive materials as ceramics, plastics, metals etc. The resulting structure generates a geometry with minimal weight, large surface area, and thermally enhanced conductive, convective and radiative properties. The physical structure undergoes thermal conduction through the material producing temperature gradients in said. By controlling the fusion process, thermal conductivity at the spherical contact points can be varied by exploitation of contact resistances. Fusion of these bodies into shape or form provides mechanically adw~mtageous properties of strength and thermal conductivity. The large surface ares generated by use of many such spherical units, enhance convection and radiation transfer.
The structure formed is generally coated with material(s) with properties of being highly remissive and selectively absorptive and reflective. Whereas thermal radiation is emitted at free surfaces to the environmental surroundings, emissions within the core of said structure are absorbed by cooler portions and reflected by others to produce temperature gradients. The addition of a surface coating(s) provides a mechanism to control this discharge process accordingly. Since thermal radiation transfer is fourth-degree temperature dependent, large fluxes are readily transferred both internal and external to the structure. Coatings of a highly remissive nature will emit thermal radiation readily. Internal emissions can also be selectively absorbed, reflected or both depending on the electromagnetic energy of the infrared photons and the properties of said coating(s).
Spherical units are used for several reasons. Uniform spheres will generally pack themselves into a symmetrical matrix, generate trivial contact areas, and radiate in a spherical nature. Packing such spheres into a shape or form can be readily controlled. Given the special dimensions of such shape or form, the dimension of the required spherical can be readily determined depending on the matrix density required. Specifically, the minimal dimension of the required special is considered the principal packing size vector. This principal packing vector is divided by an irrational fraction composed of an integer specifier raised to an arbitrary power and divided by another arbitrary number. The integer specifier is a count of the number of adjacent spheres along the peeking vector. Use of this peeking technique results in oversized spherieals which produce dimensional remainders on the peeking vector. This concept can be used to control matrix packing accordingly.
The invention is generally complimented by open channels arranged within said. Inclusion of open channels in a design facilitates the flow characteristics of said device. Forced flow across the principal axis becomes generally turbulent upon encountering diagonally arr~mged flow channels. Cross flow is readily generated through the actual spherical structure. The physical nature of said structure promotes generally turbulent inner flow. When said structure Lo is in ho prcscncc Or a ~vorl;ing Rowley in sucker static or dynamic silna~ions, thermal convection will occur. As an added bcnirn~ snip channels alto increase ho vice factor for mediation cxchan~c lo the surrounding surfaces.
The physical aspects of the invention such as porosity, fusion boundaries, open flow channels, coating(s) etc.
arcintrinsic~olhcpcrformanccof~hcdcvicc.Thcscparammmetersmustbeconsideredconcurrentlyinordertoimplemmoon the apparatus described. lattice structure and porosity directly affect convective heat transfer characteristics as does the channclling. Porosity is directly related to fusion boundaries and coating(s) thickness. Conductivity of the structure to heat is affected by fusion boundaries and spheroid material, The relations continue on, and must be summarily considered.
Manufacture of said invention begins with the spherical units as the raw component. Since geometrically perfect spheres are not necessitated ( to. as in precision ball bearings ), generally spherical elements may be utilized since they are readily produced in cost-effective quantities utilizing current techniques. Dimensionally, they would be in the range of O.5mm to 2.0mm with the only constraint being some form of statistical uniformity over a given sample.
Actual form of the invention is obtained by fusion of the spherical in combination with a die. Process descriptions of the related art can be found in US Patent #3,825,064. Straight forward die design techniques are employed for this implementation. Generally however, tapered die walls may be employed for enhallccd force distribution and easier removal of the finished structure. These die walls may also have an incremental ripple pattern to assist in forming more consistent fused structures by identically locating the spheroids. Loading of Lye die with the raw component can be enhanced with oscillation of the die to vibrate the spheres into their optimum position and an angular offset to the orientation of the die. This in combination with moderate die pressures will produce more Consistent structures. Die pressure is an important factor to control the contact resistances of the structure and hence the specific conductivity of said. These factors are optimized with regard to the maximum compressive strength of the spherical. The fused structure may then be machined flat and a thin plate of identical material fused to this area.
The thermal resistance of the invention is composed of a convective term and a conductive term. The contact resistanceduringthefusionprocessdirectlyaffectsthiiislatterterm.ltisafunctionofthewelddynamicsandtheesspheroid material. Acknowledging this, an exploitation of material sciences can be made. Here, spheroids of a highly conductive material such as aluminum are coated with a thin surface of silver. During the fusion process, the weld locations would become alloyed into a material with a slightly higher conductivity than the parent spheroids. The remaining silver surface could be reclaimed by an etching process prescribed later. Application of this technique yields a lower thermal resistance while maintaining constraints such as cost and mass within acceptable domains.
Various fusion techniques exist to complete tune formation process. Resisdve-type heating is effective for many different materials. Plasma-lype fusion methods employing large voltages can be used where material dissimilarity is present such as metal to ceramic bonding. For materials such as plastics, utilization of techniques employing sonic-welding will prove effective. The above-mentioned techniques may be used separately or in hybrid combination to effect the production of the invention.
The fusion process may cause the spheroid mass to lose some of its porosity. This can occur from excessive clilml-in~ pressures. or I Of- the clcc~rical/lllatcrial cffccls inhcircm Jo the process. A method lo reclaim this porosity Lucille is necessary for cnllanccd convcc~ivc flow of the invcn~ion, is corrosive surface etching. Here the spheroid structure is placed in a corrosive (to the malarial) bath. The conccn~ralion of Iris solution is appropriate to the desired etch spccifica~ion. Such an etching technique may generally reclaim some lost surface areas and open the interstitial spaces of the structure. This technique can also serve as a precursor to the coating(s) deposition step. Here, the surfaces of the structure are etched by a dimension that is equal lo the coating thickness to be applied later. Utilization of this technique optimizes surface area, porosity, and coating(s) deposition simultaneously.
The need lo coal Ike resulting structure with a highly em missive surface gives the invention its special ability of radiative heat transfer. The basic material of the spherical may have varying degrees of surface em missive coefficients, The optimum configuration would be black body behavior, but several materials exist that approach this level. Multiple and dissimilar coatings may also be utilized to produce surface characteristics of unique abilities. This concept is similar in nature to conductor deposition on a semiconductor material to produce logic gates. In such an implementation, the electromagnetic nature of such a surface could be highly em missive and selectively reflective or absorptive for a given energy band. The permutations of available surfaces produces a domain of such unique surfaces.
Actual deposition of the coating onto the structure may proceed in bicycle two manners. The st~mdard process of electrochemical plating may be employed for materials which are readily applied by said. Since the structure of the invention is such that small voids exist, the possibility of the plating process encompassing these voids is present. To maintain a porous structure with a uniform coating, it is advisable to have the electrochemical fluid in ntrbulent my fluctuating flow about the invention. This will result in a fluid with more consistent ion distribution for uniform plating and at the same time maintaining the geometry of the invention. The actual implementation of this concept would include the use or application of a randomly vibrating holding jig and/or an aerator bubbling system. A second method of coating deposition relies on plasma discharge. Many materials require only a highly oxidized slLrface for a high emmissivecoefficient.Thiscanbeaccomplishe(lbypassiiingaplasmastreamthroughandabouttheillventiontooxiiodize the material. Plasma coating can be extended lo deposit such materials as metals and ceramics. Careful attention to thedynamicsoftheplasmastreamisnecessary~oproduceunnniformcoatinginsuchacomplexstructureasthisinYentiloon.
By far, Ike most crucial and complex step in achieving the invention relies on coating selection and application.
Features, objects, and concepts of this invention are more readily understood symbolically trough the aid of a drawing, specifically:
Fly&. 1 is an isometric view of a Pin Grid Array (PEA) carrier package incorporating tune above-described invention's concept;
FIX&. I is an exploded cross-sectional view of a PEA carrier package showing Ike major components and details of the invention;
FIG. I is an exploded side-view of a thermal retrofit assembly;
I IT. I is a Topeka illusua~ing ho diagonal flow characteristics of ho invention;
FIG. I is a magnitl~d scgmcn~ illus~raling hl~crnal low characteristics of Ike inhalation;
FIG. 4 is an illuslra~ion depicting ho concept of controlling the compact resistances;
FIG. 5 is a schematic depicting the natural modes of heat-transfer including convection conduction radiation and internal modes of emission reflection and absorption;
FIG. I is an illustration of an example special volume with the selected packing vector;
FIG. I is an illustration of the packing concept with No FIG. I is an illustration of the packing concept with No FIG. I is an illustration of the packing concept with No FIG. I is an illustration of the packing concept with No FIG. I is a magnified top-section illustrating the rippled die walls;
FIG. I is an isometric view of an angularly offset die;
FIG. I is a schematic illustrating resistive-heating fusion method;
FIG. I is a schematic illustrating plasma-type fusion method;
FIG. I is a schematic illustrating sonic-welding fusion method;
FIG. I is an illustration of an electrochemical plating method;
FIG. I is an illustration of a plasma coating process.
A better understanding of the invention is made by specific reference to the drawings. The implementation of the invention and its concepts are readily made in various forms. In FIGURE I the heat sink 1 has a machined flat underside 2 which is fused to an intermediate plate 3 of generally identical material. This is to facilitate a substructure with uniform thermal expansion abilities which will not induce excessive stresses on the rest of the carrier package. A thermally conductive and elastic adhesive 4 typically mates the above assembly to an isolation platform 5 of high thermal conductivity but electrically insulated. Signal traces 6 wire bonds 7 and the semiconductor circuit(s) X are affixed to 5 allowing the electrical signal network to be established. This assemblage is further affixed to an electrically inert base carrier 9 with a contact pin gild array 10. The semiconductor circuit(s) S subsequently occupies theherrneti~llysealedcharnberllacccssedbycoverplatttel2.Asaretrofitdevice FlGURE2(b)illustratestheheatsink 1 with a flat underside affixed by adhesive 4 to an existing flat-top integrated circuit package 13.
The invention operates well in static air-flow situations but has improved operational characteristics in a dynamic convective air-flow. In Figure I the diagonally arranged fin-like structures Id. are illustrated with a Lo furiously Lowe vector nomlal lo at side of the pacl;agc. Upon cncounlcring ho pickax a channel tow vector 15 is established which cvcmually becomes ~urbulcnl. Synch turbulent action is further visualized in FIGURE I. Here, a substantially reduced surface flow 16 is imcrmixed with turbulent inner tows 17. This compounding turbulent affect enhances convcc~ivc heat transfer dramatically. This implementation of the invention also frees the electronic designer fromcomplicatedpans-to-floworientationoncircuitboaaardsetc.Thecarrierpackageisihuspartiallyomni-direecctional to forced flow since a turbulent convective intermix is achieved when generally normal vectored flow encounters the invention.
Spheroids are utilized in this invention because they maximize surface area and minimize mass. When implemented in this invention, some important aspects must be considered. In FIGURE 4, an illustration of fusion boundariesl8,clampingforcesl9,and~hethcrmalresistaaance20ismade,Thisisanimportantconceptoftheinventiloon which must be optimized for each implementation. The clamping force directly affects the dimension of the fusion boundaries. A too large a force will greatly reduce the surface areas generated by the spheroids, and reduce the porosity of the fused structure. This will directly affect the operation of the invention. The thermal resistance is also directly related to this consequence. The greater the cross-sectional area at the fusion boundary, the less thermal resistance of the structure to heat flow is enacted. The fused spheroid structure will have more thermal resistmce than its parent material, but with a highly conductive material it is intended that an optimized resistance will be implemented understanding the above constraints. The available modes of heat transfer are illustrated in FIGURE 5. The three main modes of convection 21, radiation 22, and conduction 23 supplemented by intemal emissions 24, reflections 25, My adsorptions 26. The nature of these modes and their effect on the invention have been previously detailed above, but it must be stressed that all are inter-related and must be optimized as such.
The porosity and arrangement of the spheroid matrix can be controlled Vito the packing vector concept outlined previous. This is graphically illustrated in FIGURE I with the selected packing vector 27. FIGURES I-(e) illustrate in two dimensions the structures formed when the size of the spheroids and the packing count is changed.
The concept is more readily understood visually, and indeed confirmed about its viability. Packing the spheroids in a desired matrix form consistently is filrther accomplished by enhancements to the fusion die. In FIGURE I, a top sectional view of the rippled die wall 28 illustrates an enhancement for uniform consistency from unit to unit. The spheroids 29 will generally arrange themselves better when ( in FIGURE I ) the die 30 is angularly offset 31 and vibrated during loading. The frequency of die vibration must be such that the individual spheroids are displaced into the more lmiform arrangement. Although these methods and concepts are not 100% effective, some consistency can still be invoked by utilization of said.
Tune principles of spheroid fusion are well know, but are illustrated in FIGURES I- . In I, the resistive heating or electric current method is depicted. This method is typically used as a preheat phase in sophisticated processes. Passing a current through a conductive spheroid mass will heat and fuse them together. A voltage discharge method as in I can also fuse spheroids together with less dimensional distortion then the above method and with the added benefit of placing an oxidized surface coating on the structure. A sonic-welding technique I is also applicable to more malleable materials such as plastic. The heat sink portion of the invention could possibly be :~3~3~
manufactllred out of plastic with high thermal conductivity with Ike binaural of minimal weight The coating processes are illustrated in FIGURES I,. In I, an electrochemical playing tank 32 is enhanced with an aerator stem 33. This in combination with an oscillating work-holding jig 34 plates a surface coating on the heat sink 1 in a turbulent fashion. Such turbulent action maintains the integrity of the porous matrix structure.
Some coatings are better applied utilizing a plasma discharge process as in FIGURE I. Here surface oxidization, or reduction reactions can be implemented on the heat sink 1 or other materials deposited upon the surface through plasma jets35.Atypicalinstallationofsuchaprocesswouldincllludeanevacuatedchamber36,aholding jig37,anddeflection magnets US.
Claims (4)
1. A thermally enhanced integrated circuit carier package comprising;
a mass of thermally conductive spheroids fused into form which generally describes a protrusion of multiple fused spheroidal submasses generally perpendicular and intrinsic to an additional submass defined as a base such that said protrusions generally assume a thin prismatic fin-like form with an orientation diagonal to a principle leading edge;
a means of attaching a flat plate of generally identical conductive material parallel to said base generally by first machining said base flat and then fusing said plate to said base;
a means of affixing such assembly to an intermediate structure which secures the electrical array generally through the application of a thin layer of thermal adhesive;
an intermediate structure of thermally conductive and electrically non-conductive material with non-porous attributes to seal out environmental penetrations with a generally thin central cross-section upon which singular or multiple semiconductor die(s) may be affixed by adhesive or other means;
an electrical array of conductive traces generally plated or other vise deposited onto the intermediate structure such that electrically conductive traces originate from the periphery of the semiconductor die(s) outward to the periphery of said intermediate structure;
a means of completing the electrical connections of the semiconductor die(s) to the electrical array generally by welding a short wirebond between the signal pads on said semiconductor die(s) to the adjacent peripheral terminal points of the electrical array, a principle carrier structure of thermally conductive and electrically non-conductive material with a central space or opening allowing access to the semiconductor die(s) and their associated electrical network terminations and including an array of contact pins coordinately located about the periphery of this principle carrier structure and protruding generally perpendicular relative to the electrical trace array through electrically inert material (generally that of the principle carrier material) and as such allowing a complete signal path from these pins to the semiconductor die(s) when the internal end-points of these contact pins are positioned sumarily upon the electrical array terminations of the intermediate assembly and maintained by means such as electrically non-conductive adhesive between such intermediate structure and said principle carrier structure;
a coverplate which is generally metallic and affixed generally by adhesive to the principle carrier structure in the location of the semiconductor circuit(s) and terminal access space thus sealing out environmental penetrations and maintaining the required internal atmostphere.
a mass of thermally conductive spheroids fused into form which generally describes a protrusion of multiple fused spheroidal submasses generally perpendicular and intrinsic to an additional submass defined as a base such that said protrusions generally assume a thin prismatic fin-like form with an orientation diagonal to a principle leading edge;
a means of attaching a flat plate of generally identical conductive material parallel to said base generally by first machining said base flat and then fusing said plate to said base;
a means of affixing such assembly to an intermediate structure which secures the electrical array generally through the application of a thin layer of thermal adhesive;
an intermediate structure of thermally conductive and electrically non-conductive material with non-porous attributes to seal out environmental penetrations with a generally thin central cross-section upon which singular or multiple semiconductor die(s) may be affixed by adhesive or other means;
an electrical array of conductive traces generally plated or other vise deposited onto the intermediate structure such that electrically conductive traces originate from the periphery of the semiconductor die(s) outward to the periphery of said intermediate structure;
a means of completing the electrical connections of the semiconductor die(s) to the electrical array generally by welding a short wirebond between the signal pads on said semiconductor die(s) to the adjacent peripheral terminal points of the electrical array, a principle carrier structure of thermally conductive and electrically non-conductive material with a central space or opening allowing access to the semiconductor die(s) and their associated electrical network terminations and including an array of contact pins coordinately located about the periphery of this principle carrier structure and protruding generally perpendicular relative to the electrical trace array through electrically inert material (generally that of the principle carrier material) and as such allowing a complete signal path from these pins to the semiconductor die(s) when the internal end-points of these contact pins are positioned sumarily upon the electrical array terminations of the intermediate assembly and maintained by means such as electrically non-conductive adhesive between such intermediate structure and said principle carrier structure;
a coverplate which is generally metallic and affixed generally by adhesive to the principle carrier structure in the location of the semiconductor circuit(s) and terminal access space thus sealing out environmental penetrations and maintaining the required internal atmostphere.
2. A heat exchange component as defined in claim 1 which comprises the fusion of spheroidal particles which have been coated with additional materials for the purpose of inducing alloyed weld points in such fusion processes.
3. A heat exchange component as defined in claim 1 which has been etched in a corrosive fashion to broaden the interstitial voids of such fused structure to enhance porousity and allow the deposition of surface coatings.
4. A heat exchange component as defined in claim 1 which has been coated with material(s) enhancing the radiative transfer of thermal energy and said coatings generally being highly emissive.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000545109A CA1238428A (en) | 1987-08-21 | 1987-08-21 | Thermally enhanced integrated circuit carrier package |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000545109A CA1238428A (en) | 1987-08-21 | 1987-08-21 | Thermally enhanced integrated circuit carrier package |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1238428A true CA1238428A (en) | 1988-06-21 |
Family
ID=4136320
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000545109A Expired CA1238428A (en) | 1987-08-21 | 1987-08-21 | Thermally enhanced integrated circuit carrier package |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1238428A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1991013462A3 (en) * | 1990-02-23 | 1991-10-17 | Lanxide Technology Co Ltd | Methods of forming electronic packages |
| US5205353A (en) * | 1989-11-30 | 1993-04-27 | Akzo N.V. | Heat exchanging member |
| US5526867A (en) * | 1988-11-10 | 1996-06-18 | Lanxide Technology Company, Lp | Methods of forming electronic packages |
| WO1999009594A1 (en) * | 1997-08-20 | 1999-02-25 | Frank Baxmann | Sintered heat sink |
| EP1263040A2 (en) * | 2001-06-01 | 2002-12-04 | Delphi Technologies, Inc. | High performance heat sink for electronics cooling |
| US6898082B2 (en) | 2002-05-10 | 2005-05-24 | Serguei V. Dessiatoun | Enhanced heat transfer structure with heat transfer members of variable density |
| EP1923914A1 (en) * | 2005-08-11 | 2008-05-21 | Mitsubishi Denki Kabushiki Kaisha | Heat sink and method of producing the same |
| EP1946032A1 (en) * | 2005-11-07 | 2008-07-23 | 3M Innovative Properties Company | Structured thermal transfer article |
| EP2989659A4 (en) * | 2013-04-23 | 2017-04-12 | Alexiou & Tryde Holding ApS | Heat sink having a cooling structure with decreasing structure density |
| DE102019218839A1 (en) * | 2019-12-04 | 2021-06-10 | Zf Friedrichshafen Ag | Device for monitoring a vehicle interior and method for dissipating heat from a device for monitoring a vehicle interior |
-
1987
- 1987-08-21 CA CA000545109A patent/CA1238428A/en not_active Expired
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5163499A (en) * | 1988-11-10 | 1992-11-17 | Lanxide Technology Company, Lp | Method of forming electronic packages |
| US5526867A (en) * | 1988-11-10 | 1996-06-18 | Lanxide Technology Company, Lp | Methods of forming electronic packages |
| US5205353A (en) * | 1989-11-30 | 1993-04-27 | Akzo N.V. | Heat exchanging member |
| WO1991013462A3 (en) * | 1990-02-23 | 1991-10-17 | Lanxide Technology Co Ltd | Methods of forming electronic packages |
| WO1999009594A1 (en) * | 1997-08-20 | 1999-02-25 | Frank Baxmann | Sintered heat sink |
| EP1263040A3 (en) * | 2001-06-01 | 2005-05-25 | Delphi Technologies, Inc. | High performance heat sink for electronics cooling |
| EP1263040A2 (en) * | 2001-06-01 | 2002-12-04 | Delphi Technologies, Inc. | High performance heat sink for electronics cooling |
| US6898082B2 (en) | 2002-05-10 | 2005-05-24 | Serguei V. Dessiatoun | Enhanced heat transfer structure with heat transfer members of variable density |
| EP1923914A1 (en) * | 2005-08-11 | 2008-05-21 | Mitsubishi Denki Kabushiki Kaisha | Heat sink and method of producing the same |
| EP1923914A4 (en) * | 2005-08-11 | 2010-01-27 | Mitsubishi Electric Corp | Heat sink and method of producing the same |
| US8371367B2 (en) | 2005-08-11 | 2013-02-12 | Mitsubishi Denki Kabushiki Kaisha | Heat sink and fabricating method of the same |
| EP1946032A1 (en) * | 2005-11-07 | 2008-07-23 | 3M Innovative Properties Company | Structured thermal transfer article |
| EP1946032A4 (en) * | 2005-11-07 | 2010-10-06 | 3M Innovative Properties Co | Structured thermal transfer article |
| EP2989659A4 (en) * | 2013-04-23 | 2017-04-12 | Alexiou & Tryde Holding ApS | Heat sink having a cooling structure with decreasing structure density |
| DE102019218839A1 (en) * | 2019-12-04 | 2021-06-10 | Zf Friedrichshafen Ag | Device for monitoring a vehicle interior and method for dissipating heat from a device for monitoring a vehicle interior |
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