No-lead IC packages having integrated heat spreader for electromagnetic interference (EMI) shielding and thermal enhancement

• US 8,183,680 B2
• Filed: 07/05/2006
• Issued: 05/22/2012
• Est. Priority Date: 05/16/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Zhao, Sam Ziqun, Khan, Rezaur Rahman
• Primary Examiner(s): Sandvik, Benjamin
• Assistant Examiner(s): SODERHOLM, KRISTA Z
• Application Number:
  US11/480,579
• Publication Number:
  US 20070267734A1
• Time in Patent Office: 2,148 Days
• Field of Search: 257/687, 257/E21.506, 438/119
• US Class Current: 257/687
• CPC Class Codes: H01L 21/561 Batch processing
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/451 with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48233 connecting the wire to a potential ring of the item
• CPC Class Codes: H01L 2224/48237 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48253 connecting the wire to a potential ring of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/49109 outside the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/4911 the connectors being bonded to at least one common bonding area, e.g. daisy chain
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 2224/85 using a wire connector
• CPC Class Codes: H01L 2224/92 : Specific sequence of method steps
• CPC Class Codes: H01L 2224/92247 : the second connecting process involving a wire connector
• CPC Class Codes: H01L 2224/97 : the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 23/3107 : the device being completely enclosed
• CPC Class Codes: H01L 23/3128 : the substrate having spherical bumps for external connection
• CPC Class Codes: H01L 23/4334 : Auxiliary members in encapsulations H01L23/49568 takes precedence
• CPC Class Codes: H01L 23/49503 : characterised by the die pad
• CPC Class Codes: H01L 23/49816 : Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 23/552 : Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/49 : of a plurality of wire connectors
• CPC Class Codes: H01L 24/73 : Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 24/97 : the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : 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
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/078 : Adhesive characteristics other than chemical
• CPC Class Codes: H01L 2924/0781 : being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/1532 : the connection portion being formed on the die mounting surface of the substrate
• CPC Class Codes: H01L 2924/16151 : Cap comprising an aperture, e.g. for pressure control, encapsulation
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/166 : Material
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19043 : being a resistor
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/30105 : Capacitance
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: H01L 2924/3512 : Cracking

Abstract

Methods and apparatus for improved thermal performance and electromagnetic interference (EMI) shielding in integrated circuit (IC) packages are described. A die-up or die-down package includes an IC die, a die attach pad, a heat spreader cap coupled to the die attach pad defining a cavity, and one or more peripheral rows of leads surrounding the die attach pad. The leads do not protrude substantially from the footprint of the encasing structure. The die attach pad and the heat spreader cap defines an encasing structure that substantially encloses the IC die, and shields EMI emanating from and radiating towards the IC die. The encasing structure also dissipates heat generated by the IC die during operation.

Claims

1. An integrated circuit (IC) device package, comprising:

an IC die having bond pads;

an encasing structure that substantially encloses the IC die, comprising;

a leadframe, including;

a die attach pad having a substantially planar central portion with opposing first and second surfaces, wherein the first surface of the central portion of the die attach pad has the IC die mounted on,

a plurality of tie bars, each tie bar being coupled to the die attach pad, wherein a. tie bar of the plurality of tie bars comprises at least one receptacle, and

a plurality of leads emanating outward from the IC die, each lead being coupled to a bond pad of the bond pads, wherein a tie bar of the plurality of tie bars is coupled to at least two leads of the plurality of leads; and

a cap having a cavity and a planar rim surrounding the cavity, such that the cavity faces the IC die, wherein the cap is coupled to the leadframe, wherein the cap comprises at least one tab protruding from the planar rim, and wherein the at least one tab mates with the at least one receptacle; and

a molding material that substantially encapsulates the IC die and at least partially fills the cavity.

2. The package of claim 1, wherein the package is in a die-up or die-down configuration.

3. The package of claim 1, wherein the encasing structure is constructed and arranged to spread heat from the IC die during operation of the IC die.

4. The package of claim 1, wherein the encasing structure is constructed and arranged to shield electromagnetic interference (EMI) emanating from the IC die and EMI radiating toward the IC die from outside the package.

5. The package of claim 1, wherein one or more perimeter support rings or dam bars structurally connect the leads.

6. The package of claim 1, wherein the leads are arranged in an array with more than one row.

7. The package of claim 6, further comprising one or more interposer conducting rings coupled to the tie bars surrounding the die attach pad.

8. The package of claim 7, wherein one or more perimeter support rings or dam bars structurally connect the leads.

9. The package of claim 1, wherein the rim of the cap includes a substantially planar lip portion extending outwards from the cavity that encloses the IC die.

10. The package of claim 1, wherein the cap is in electrical and thermal contact with at least one lead.

11. The package of claim 1, wherein the cap is electrically isolated from any of the plurality of leads.

12. The package of claim 1, wherein at least a portion of the planar rim of the cap is coated with a dielectric material.

13. The package of claim 1, wherein at least a portion of the die attach pad coupled to the cap is coated with a dielectric material.

15. The package of claim 1, wherein at least one of the plurality of leads is wider relative to others of the plurality of leads.

17. The package of claim 1, wherein the plurality of tie bars and the plurality of leads are positioned in a first plane.

18. The package of claim 1, wherein the plurality of tie bars are positioned in a first plane and the plurality of leads are positioned in a second plane.

19. The package of claim 1, wherein the planar rim portion of the cap is coupled to the die attach pad by a thermally and electrically conductive adhesive.

20. The package of claim 1, further comprising:

at least one electrically conductive plated area patterned on the die attach pad such that the plated area is in contact with the planar rim portion of the cap.

21. The package of claim 1, wherein the cap is electrically insulated from the die attach pad.

22. The package of claim 1, wherein the cap is coupled to a ground potential.

24. The package of claim 1, further comprising:

a thermally and electrically conductive adhesive in the at least one receptacle.

25. The package of claim 1, wherein the at least one tab has a conical, frustum, or laterally elongated shape.

26. The package of claim 1, wherein a tab is positioned on a corner of the planar rim portion.

27. The package of claim 1, wherein the at least one corresponding receptacle has an opening, indentation, or edge cutout configuration.

28. The package of claim 1, wherein the at least one tab and the at least one corresponding receptacle are configured to facilitate coupling the cap to the die attach pad in a predetermined orientation.

29. The package of claim 1, further comprising:

at least one wire bond that couples at least one bond pad on the IC die to the encasing structure, whereby the encasing structure is coupled to an electrical potential.

30. The package of claim 29, wherein the at least one bond pad is a ground pad, whereby the encasing structure is coupled to a ground potential.

31. The package of claim 1, wherein the cap has an outer surface that opposes the cavity, wherein a first portion of the outer surface is covered by the molding material, and wherein a second portion of the outer surface of the cap is not covered by the molding material.

32. The package of claim 1, wherein the molding material further encapsulates an outer surface of the cap that opposes the cavity.

33. The package of claim 1, wherein the cap has an outer surface that opposes the cavity, wherein the cap further comprises:

at least one opening through the cap that is open at the outer surface and conneds to the cavity.

34. The package of claim 33, wherein the at least one opening through the cap is configured to facilitate flow of a molding material into the cavity.

35. The package of claim 33, wherein the at least one opening through the cap is configured to facilitate release of an air pressure inside of the encasing structure.

36. The package of claim 1, wherein a peripheral dimension of the cap substantially coincides with a peripheral dimension of the substantially planar area enclosed by the peripheral row of leads.

37. The package of claim 1, wherein a peripheral dimension of the cap is within a peripheral dimension of the substantially planar area enclosed by the peripheral row of leads.

38. The package of claim 1, wherein a peripheral dimension of the cap exceeds a peripheral dimension of the substantially planar area enclosed by the peripheral row of leads.

39. The package of claim 1, wherein the cap has an outer surface that opposes the cavity, further comprising:

a heat sink coupled to the outer surface of the cap.

40. The package of claim 1, wherein the cap has an outer surface that opposes the cavity, wherein the outer surface of the cap is configured to be coupled to a substrate including a printed circuit board (PCB) and a printed wire board (PWB).

41. The package of claim 40, further comprising a thermally and electrically conductive adhesive coupling the outer surface of the cap to the substrate.

42. The package of claim 1, wherein the second surface of the central portion of the die attach pad is exposed to be coupled to a substrate including a printed circuit board and a printed wire board.

43. The package of claim 42, further comprising a thermally and electrically conductive adhesive coupling the die attach pad to the substrate.

44. The package of claim 1, wherein the package further comprises:

a heat slug, having a first surface coupled to an exposed second surface of the central portion of the die attach pad, and a second surface configured to be coupled to a substrate including a printed circuit board and a printed wire board.

45. The package of claim 1, wherein the encasing structure and the molding material provide environmental protection to the IC die.

46. The package of claim 1, wherein the encasing structure and the molding material is constructed and arranged to provide damping against mechanical shock and vibrations.

47. The package of claim 1, wherein the cap and the die attach pad are made of similar material including metal, metallic alloy, ferromagnetic material, and metallized polymer.

48. The package of claim 1, wherein the cap and the the attach pad are made of dissimilar materials.

49. The package of claim 1, wherein the package is a no-lead package.

14. An integrated circuit (IC) device package, comprising:

an IC die having bond pads;

an encasing structure that substantially encloses the IC die, comprising;

a die attach pad having a substantially planar central portion with opposing first and second surfaces, and a plurality of tie bars coupled to and extending from the central portion, wherein the first surface of the central portion of the die attach pad has the IC die mounted on thereon, and

a cap having a cavity and a planar rim surrounding the cavity, such that the cavity faces the IC die when the rim is attached to the die attach pad, thereby enclosing the IC die;

a plurality of leads having lead fingers for wire bonding arranged in at least one peripheral row surrounding the die attach pad; and

a molding material that substantially encapsulates the IC die and at least partially fills the cavity, wherein at least one of the plurality of tie bars is wider relative to others of the plurality of tie bars.

16. An integrated circuit (IC) device package, comprising:

an IC die having bond pads;

an encasing structure that substantially encloses the IC die, comprising;

a die attach pad having a substantially planar central portion with opposing first and second surfaces, and a plurality of tie bars coupled to and extending from the central portion, wherein the first surface of the central portion of the die attach pad has the IC die mounted on thereon, and

a cap having a cavity and a planar rim surrounding the cavity, such that the cavity faces the IC die when the rim is attached to the die attach pad, thereby enclosing the IC die;

a plurality of leads having lead fingers for wire bonding arranged in at least one peripheral row surrounding the die attach pad; and

a molding material that substantially encapsulates the IC die and at least partially fills the cavity, wherein the cap is in electrical and thermal contact with at least one tie bar.

23. An integrated circuit (IC) device package, comprising:

an IC die having bond pads;

an encasing structure that substantially encloses the IC die, comprising;

a die attach pad having a substantially planar central portion with opposing first and second surfaces, and a plurality of tie bars coupled to and extending from the central portion, wherein the first surface of the central portion of the die attach pad has the IC die mounted on, and

a cap having a cavity and a planar rim surrounding the cavity, such that the cavity faces the IC die when the rim is attached to the die attach pad, thereby enclosing the IC die;

a plurality of leads having lead fingers for wire bonding arranged in at least one peripheral row surrounding the die attach pad; and

a molding material that substantially encapsulates the IC die and at least partially fills the cavity, Wherein the cap is coupled to a power potential.