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
  • H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
  • H01L23/433—Auxiliary members in containers characterised by their shape, e.g. pistons
• • 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
  • H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
  • H01L23/433—Auxiliary members in containers characterised by their shape, e.g. pistons
  • H01L23/4334—Auxiliary members in encapsulations
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
  • H01L2224/42—Wire connectors; Manufacturing methods related thereto
  • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
  • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
  • H01L2224/4805—Shape
  • H01L2224/4809—Loop shape
  • H01L2224/48091—Arched
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
  • H01L2224/42—Wire connectors; Manufacturing methods related thereto
  • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
  • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
  • H01L2224/481—Disposition
  • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
  • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
  • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
  • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
  • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
  • H01L2224/42—Wire connectors; Manufacturing methods related thereto
  • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
  • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
  • H01L2224/484—Connecting portions
  • H01L2224/48463—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
  • H01L2224/48465—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
  • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
  • H01L24/42—Wire connectors; Manufacturing methods related thereto
  • H01L24/47—Structure, shape, material or disposition of the wire connectors after the connecting process
  • H01L24/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
• • 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
  • H01L2924/00014—Technical content checked by a classifier the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• • 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
  • H01L2924/01—Chemical elements
  • H01L2924/01013—Aluminum [Al]
• • 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
  • H01L2924/01—Chemical elements
  • H01L2924/01029—Copper [Cu]
• • 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
  • H01L2924/10—Details of semiconductor or other solid state devices to be connected
  • H01L2924/11—Device type
  • H01L2924/14—Integrated circuits
• • 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
  • H01L2924/15—Details of package parts other than the semiconductor or other solid state devices to be connected
  • H01L2924/181—Encapsulation

Definitions

• the present invention relates generally to integrated circuit packaging and more specifically to an integrated circuit package including a particularly designed heat sink which, in a preferred embodiment, has a surface thereof exposed to the exterior of the integrated circuit package.
• the cost and reliability of the components making up the package are major concerns. Any reduction in the cost or improvement in the reliability of these components making up the package can provide a significant commercial advantage.
• the packaging of integrated circuits is continuously being improved to provide more cost effective designs and methods of producing integrated circuit packages.
• the prior art approaches to providing a heat sink have typically involved fairly complex shapes. These shapes are designed to allow one of the surfaces of the heat sink to be exposed to the exterior of the encapsulating material making up the integrated circuit package while providing an arrangement for locking the heat sink in place within the molded package.
• the heat sink has several different features including multiple surfaces having different thicknesses, fins protruding outwardly from the main body of the heat sink, holes formed in the heat sink, and various other features. All of these relatively complex shaped features make this heat sink more expensive and relatively difficult to mass produce.
• FIG. 1 illustrates an lntegruted circuit package generally designated by reference numeral 10.
• Integrated circuit package 10 includes a heat sink 12 having a top surface 14 (which may be adapted to support an integrated circuit die or other device), a bottom surface 16, and an outermost peripheral edge surface 18.
• Peripheral edge surface 18 includes a fish-tail shaped protrusion 20 extending outwardly.
• Integrated circuit package 10 also includes an encapsulating material 22 surrounding all of heat sink 12 except bottom surface 16 which remains exposed at the exterior surface of integrated circuit package 10. Fish-tail protrusion 20 cooperates with encapsulating material 22 to mechanically hold heat sink 12 in position within integrated circuit package 10.
• FIG. 2 illustrates an integrated circuit package generally designated by reference numeral 24.
• Integrated circuit package 24 includes a heat sink 26 having a top surface 28 (which may be adapted to support an integrated circuit die or other device), a bottom surface 30, a peripheral edge surface 32, and a curved pocket 34 formed around the periphery of bottom surface 30.
• Integrated circuit package 24 also includes an encapsulating material 36 surrounding all of heat sink 12 except bottom surface 16 which remains exposed at the exterior surface of integrated circuit package 10. Curved pocket 34 cooperates with encapsulating material 36 to mechanically hold heat sink 26 in position within integrated circuit package 24.
• the present invention provides a reliable, easy to mass produce heat sink for use in an integrated circuit package in which the heat sink, in a preferred embodiment, has a surface of the heat sink exposed to the exterior of the integrated circuit package.
• a heat sink for use in an integrated circuit package having at least one integrated circuit die and an encapsulating material for molding the tm ⁇ gruied ⁇ lr ⁇ uli die ami ui leant a part of the heat alnk Into the lntagruiad ⁇ lruuil package during the manufacture of the package is disclosed.
• the heat sink includes a main body formed of a thermally conductive material.
• the main body has (i) an upwardly facing horizontally extending top surface adapted to support the integrated circuit die either directly or indirectly, (ii) a downwardly facing horizontally extending bottom surface, (iii) an outer circumferential edge, and (iv) a slot extending a predetermined distance into the main body along the entire circumferential edge between the top surface and the bottom surface of the main body.
• the slot is adapted to receive the encapsulating material during the molding of the integrated circuit package thereby forming a mechanical connection between the heat sink and the package.
• the bottom surface of the heat sink is exposed on an external surface of the integrated circuit package after the molding of the integrated circuit package is complete.
• the main body of the heat sink has (i) a central portion , (ii) an outer peripheral portion, (iii) an upwardly facing horizontally extending top surface adapted to support the integrated circuit die either directly or indirectly, (iv) a downwardly facing horizontally extending bottom surface, (v) an outer circumferential edge, and (vi) a continuous downwardly facing V-shaped recess having an innermost and an outermost opposing sidewall.
• the recess is formed into the bottom surface of the outer peripheral portion of the main body adjacent to the outer circumferential edge.
• the outermost sidewall is shorter than the innermost sidewall such that the thickness of the heat sink at its outer circumferential edge is less than the thickness of the central portion of the main body.
• the recess is adapted to receive the encapsulating material during the molding of the integrated circuit package thereby forming a mechanical connection between the heat sink and the package.
• the bottom surface of the heat sink is exposed on an external surface of the integrated circuit package after the molding of the integrated circuit package is complete.
• Figure 1 is a diagrammatic cross sectional view of a first prior art heat sink shown assembled into an integrated circuit package
• Figure 2 is a diagrammatic cross sectional view of a second prior art heat sink shown assembled into an integrated circuit package
• Figure 3 is a diagrammatic cross sectional view of an integrated circuit package including a first embodiment of a heat sink in accordance with the present invention
• Figure 4 is a diagrammatic cross sectional view of an integrated circuit package including a second embodiment of a heat sink in accordance with the present invention
• Figure 5 is a diagrammatic cross sectional view of an integrated circuit package including a third embodiment of a heat sink in accordance with the present invention.
• Figures 6A-C are diagrammatic plan views of the undersides of several variations of an integrated circuit package including a heat sink in accordance with the present invention with the leads of the package not being shown.
• Integrated circuit package 38 Includes (1) an Integrated circuit die 40 huvlng a plurality of input/output terminals 42, (ii) a lead frame 44 having a plurality of electrically conductive leads 46 for electrically connecting package 38 to other electrical components but absent its die attach pad, (iii) an array of bonding wires 48 electrically connecting certain integrated circuit die input/output terminals 42 to associated leads 46 of leadframe 44, and (iv) an encapsulating material 50 surrounding integrated circuit die 40, bonding wires 48, and portions of lead frame 44.
• Integrated circuit package 38 also includes a heat sink 52, which in this embodiment, directly supports die 40 and lead frame 44.
• lead frame 44 may include a die attach pad for supporting die 40 and the die attach pad may be supported by the heat sink 52 which therefore would support die 40 indirectly.
• heat sink 52 includes a main body 54 formed of a thermally conductive material. This material may be copper, aluminum, or a variety of other thermally conductive materials such as thermally conductive ceramics or other metal alloys.
• Main body 54 of heat sink 52 has an upwardly facing horizontally extending top surface 56 adapted to support integrated circuit die 40 (or as mentioned above a die attach pad of lead frame 44), a downwardly facing horizontally extending bottom surface 58, and an outer circumferential edge 60.
• heat sink 52 further includes a slot 62 extending a predetermined distance into main body 54 along the entire circumferential edge 60 between top surface 56 and bottom surface 58.
• Slot 62 is filled with encapsulating material 50 during the molding of the integrated circuit package thereby forming a strong and reliable mechanical connection between heat sinkeredmpfickick T -, ⁇
• bottom surface 58 of heat sink 52 cooperates with an integrated circuit package mold (not shown) during the manufacture of package 38 such that bottom surface 58 of heat sink 52 is exposed on an external surface 64 of integrated circuit package 38 after the molding of the integrated circuit package is complete.
• slot 62 formed into main body 54 of heat sink 52 Includes beveled edges 66 along the entire circumferential edge 60 of main body
• Beveled edges 66 provide an enlarged entrance opening into slot 62 for allowing encapsulating material 50 to more easily fill slot 62 during the molding process. It is to be understood that beveled edges 66 are not a requirement of the present invention and the invention equally applies to a heat sink including a slot without beveled edges although beveled edges are preferred. Also, it should be understood that the beveled edges may be a wide variety of sizes depending on the requirements of the application in which the heat sink is to be used. As illustrated, the bevels do not extend to the top and bottom surfaces 56 and 58 of main body 54 but rather define upper and lower square edges 67. These square edges ad structural rigidity to the overall configuration.
• heat sink 52 Since slot 62 is filled with encapsulant material 50, a relatively long interface path between heat sink 52 and encapsulating material 50 is formed. This long interface path provides a reliable seal that prevents moisture or other contaminants from penetrating package 38 and damaging the internal components of the package. Also, since heat sink 52 is a relatively simple shape, it may be easily mass produced at a low cost by methods of casting or machining from a sheet stock of the appropriate material.
• integrated circuit package generally designated by reference numeral 68 and including a heat sink in accordance with the present invention will be described.
• integrated circuit 68 would also typically include die 40, lead frame 44 (with or without a die attach pad, bonding wires 48, and encapsulating material 50.
• this embodiment includes a heat sink 70 having a main body 72 formed of a thermally conductive material as described above for heat sink 52 but a different shape.
• main body 72 of heat sink 70 has a central portion 74, an outer portion 76, an upwardly facing horizontally extending top surface 78 adapted to support integrated circuit die 40 (or a die attach pad), a downwardly facing horizontally extending bottom surface 80, and an outer circumferential edge 82.
• heat sink 72 also includes a continuous downwardly facing V-shaped recess 84 having an innermost sidewall 86 and an outermost opposing sidewall 88. Recess 84 is formed into the bottom surface within outer peripheral portion 76 adjacent to outer circumferential edge 82. Outermost sidewall 88 is shorter than innermost sidewall 86 such that the thickness of heat sink 70 at its outer circumferential edge 82 is less than the thickness of central portion 74 of the main body 72.
• Recess 84 receives encapsulating material 50 during the molding of integrated circuit package 68 thereby forming a mechanical connection between heat sink 70 and package 68. Also, as shown in Figures 4 and 5, bottom surface 80 of heat sink 70 cooperates with an integrated circuit package mold (not shown) during the manufacture of the package such that bottom surface 80 of the heat sink 70 is exposed on an external surface 90 of integrated circuit package 68 after the molding of the integrated circuit package is complete.
• recess 84 is filled with encapsulating material 50 during the molding of the package, a relatively long interface path between heat sink 70 and encapsulating material 50 is formed. This long interface path helps prevent moisture and other contaminants from penetrating the overall package and damaging the internal components thereby improving the reliability of the package.
• heat sink 70 may be formed by a variety of methods.
• heat sink 70 is formed by ether machining or casting an appropriate thermally conductive material into the described shape.
• this material is typically copper or aluminum, however, other materials such as thermally conductive ceramics or other metal alloys may be used.
• this same basic heat sink shape may be formed using a stamping or punching technique where the material making up the heat sink lends itself to this. With this stamping or punching approach, the entire heat sink may be formed in one rapid step which stamps or punches heat sink 70 into its final shape including recess 84 from a sheei of the appropriate material stock. This approach, in accordance with the present
• ullo n heat sink 70 to bo mans produce in a very low cost manner while still providing a reliable heat sink that has a strong mechanical connection to the overall package and provides a reliable seal at the interface between the heat sink and the encapsulating material as described above.
• heat sinks of the present invention may take on a wide variety of shapes when viewed in the plan view. These shapes include, but are not limited to, circular, square, or rectangular shapes as shown in Figures 6A, 6B, and 6C, respectively. Other shapes such as oval or other polygon shapes would also fall within the spirit and scope of the present invention.

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• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

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• 1996
  • 1996-03-06 EP EP96910413A patent/EP0758488A1/de not_active Withdrawn
  • 1996-03-06 WO PCT/US1996/003282 patent/WO1996027903A1/en not_active Application Discontinuation
  • 1996-10-29 KR KR1019960706107A patent/KR970703045A/ko not_active Application Discontinuation

Non-Patent Citations (1)

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