Packaging of semiconductor circuit in pre-molded plastic package

• US 5,869,883 A
• Filed: 09/26/1997
• Issued: 02/09/1999
• Est. Priority Date: 09/26/1997
• Status: Expired due to Term

• Current Assignee: Pantronix Corporation
• Original Assignee: Stanley WANG President Pantronix Corporation
• Inventors: Oh, Charlie, Mehringer, Larry H.
• Primary Examiner(s): Ngo, Ngan V.
• Application Number:
  US08/938,874
• Time in Patent Office: 501 Days
• Field of Search: 257/667, 257/668, 257/669, 257/673, 257/674, 257/675, 257/676, 257/682, 257/687, 257/688, 257/689, 257/706, 257/727
• US Class Current: 257/667
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/05599 Material
• 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 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• 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 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/16 Fillings or auxiliary members in containers or encapsulations, e.g. centering rings H01L23/42, H01L23/552 take precedence
• CPC Class Codes: H01L 23/4334 Auxiliary members in encapsulations H01L23/49568 takes precedence
• CPC Class Codes: H01L 24/48 of an individual wire connector
• 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 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 2924/01077 Iridium [Ir]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/16195 : Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/207 : Diameter ranges
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding

Abstract

An inexpensive pre-molded package for electronic semiconductor circuit with increased thermal extraction capability, improved electrical performance, improved dielectric constant of sealing medium, optically transmissive sealing lid, and partially reduced electromagnetic radiation. In one embodiment, the pre-molded package includes electronic semiconductor circuit, a plurality of electrically conductive leads, a heat spreader, a plurality of electrically conductive bond wires, and a seal lid. Preferably, a surface of the heat spreader remains exposed to the exterior of the pre-molded package. In another embodiment, the pre-molded package includes a semiconductor circuit, a plurality of electrically conductive leads, a heat spreader, a plurality of electrically conductive bond wires, and an optically transmissive seal lid.

Claims

1. A pre-molded package structure for electronic circuit components comprising:

(a) a lead frame defining a semiconductor circuit location having terminal leads extending therefrom;

(b) a pre-molded body of plastic material enclosing the lead frame semiconductor circuit location and defining a package having opposed sides and opposed edges with terminal leads extending from at least one of said opposed edges;

(c) an electronic semiconductor circuit positioned in said semiconductor circuit location and in electrical communication with said terminal leads; and

(d) a body of thermally conductive material partially contained within said pre-molded body of plastic, said body of thermally conductive material having first and second opposed major faces and a retaining flange extending inward and at least partially defining the edge surfaces thereof connected to said lead frame with said first major face in thermal contact with said electronic semiconductor circuit and said second major face substantially parallel with and adjacent one of said opposed sides of said package extending to the surface of the package body.

2. A structure as defined in claim 1 wherein said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said die paddle with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated.

3. A structure as defined in claim 1 wherein said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said upper-face of semiconductor circuit with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated.

4. A structure as defined in claim 1 wherein said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said die paddle with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated;

and said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said upper-face of semiconductor circuit with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated.

5. A structure as defined in claim 1 wherein said lead frame includes a die paddle with a secured rerouting board and said first major face of said thermally conductive body is secured to said die paddle with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated;

and said lead frame includes a die paddle secured rerouting board with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said upper-face of semiconductor circuit with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated.

6. A structure as in claim 1, further comprising a barrier metal plated heat spreader composed of copper, oxygen-free high thermal conductivity copper or the like.

7. A structure as in claim 1, further comprising a pressure sensitive foil composed of copper, aluminum or the like to attach heat spreader to die paddle.

8. A structure as in claim 1, further comprising a pressure sensitive foil composed of copper, aluminum or the like to attach heat spreader to rerouting board.

9. A structure as in claim 1, further comprising a thermal grease composed of thermal grease and filled with aluminum oxide, aluminum nitride or the like, to attach heat spreader to die paddle.

10. A structure as in claim 1, further comprising a thermal grease composed of thermal grease and filled with aluminum oxide, aluminum nitride or the like, to attach heat spreader to rerouting board.

11. A structure as in claim 1, further comprising a pressure sensitive foil composed of copper, aluminum or the like to attach heat spreader to semiconductor circuit.

12. A structure as in claim 1, further comprising a thermal grease composed of thermal grease and filled with aluminum oxide, aluminum nitride or the like, to attach heat spreader to semiconductor circuit.

13. A structure as in claim 1, wherein at least one inwardly extending retaining flange is formed around the circumference of the exposed body section of the heat spreader to provide a mechanical interlock.

14. A structure as in claim 1, wherein the arrangement of heat spreader metal body increases the surface area of the heat spreader and provides for ejection molding without mold flash or molding compound on the heat spreader exposed improved surface area.

15. A structure as in claim 1, wherein at least one transmissive lens is formed in the seal lid to provide path for ultra violet, infrared, or optical rays to penetrate from the pre-molded package plastic body to the external environment.

16. A pre-molded package structure for electronic circuit components comprising:

(a) a lead frame defining a semiconductor circuit location having terminal leads extending therefrom;

(b) a pre-molded body of plastic material defining the lead frame semiconductor circuit location and defining a pre-molded package having opposed sides and opposed edges with terminal leads extending from at least one of said opposed edges;

(c) an electronic semiconductor circuit positioned in said semiconductor circuit location and in electrical communication with said terminal leads; and

(d) a body of thermally conductive material contained within said pre-molded body of plastic, said body of thermally conductive material having first and second opposed major faces and a retaining flange extending inward and at least partially defining the edge surfaces thereof connected to said lead frame with said first major face in thermal contact with said electronic semiconductor circuit and said second major face substantially parallel with and adjacent one of said opposed sides of said package but covered with a seal lid material.

17. A structure as defined in claim 16 wherein said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said die paddle with pressure sensitive foil, aluminum filled thermal grease, or the like and said thermally conductive body is barrier plated.

18. A structure as defined in claim 16 wherein said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said upper-face of semiconductor circuit with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated.

19. A structure as defined in claim 16 wherein said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said die paddle with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated;

and said lead frame includes a die paddle with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said upper-face of semiconductor circuit with pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated.

20. A structure as defined in claim 16 wherein said lead frame includes a die paddle with a secured rerouting board and said first major face of said thermally conductive body is secured to said die paddle with pressure sensitive foil, thermal grease filled with aluminum oxide or the like and said thermally conductive body is barrier plated;

and said lead frame includes a die paddle secured rerouting board with a secured semiconductor circuit and said first major face of said thermally conductive body is secured to said upper-face of semiconductor circuit with no adhesive, pressure sensitive foil, thermal grease filled with aluminum oxide, or the like and said thermally conductive body is barrier plated.

21. A structure as in claim 16, further comprising a barrier metal plated heat spreader composed of copper, oxygen-free high thermal conductivity copper, or the like.

22. A structure as in claim 16, further comprising a pressure sensitive foil composed of copper, aluminum, or the like to attach heat spreader to die paddle.

23. A structure as in claim 16, further comprising a pressure sensitive foil composed of copper, aluminum, or the like to attach heat spreader to rerouting board.

24. A structure as in claim 16, further comprising a thermal grease composed of thermal grease and filled with aluminum oxide, aluminum nitride, or the like to attach heat spreader to die paddle.

25. A structure as in claim 16, further comprising a thermal grease composed of thermal grease and filled with aluminum oxide, aluminum nitride, or the like to attach heat spreader to rerouting board.

26. A structure as in claim 16, further comprising a pressure sensitive foil composed of copper, aluminum, or the like to attach heat spreader to semiconductor circuit.

27. A structure as in claim 16, further comprising a thermal grease composed of thermal grease and filled with aluminum oxide, aluminum nitride, or the like to attach heat spreader to semiconductor circuit.

28. A structure as in claim 16, wherein at least one inwardly extending retaining flange is formed around the circumference of the molded body section of the heat spreader to provide a mechanical interlock.

29. A structure as in claim 16, wherein at least one transmissive lens is formed in the seal lid to provide path for ultra violet, infrared, or optical rays to penetrate from the pre-molded package plastic body to the external environment.

30. A pre-molded package structure for electronic circuit components comprising:

(a) a lead frame defining a semiconductor circuit location having terminal leads extending therefrom;

(b) a pre-cast die attach cavity spacer attached to the lead frame providing semiconductor circuit location and defining a package having opposed sides and opposed edges with terminal leads extending from at least one of said opposed edges; and

(c) wherein at least one body of thermally conductive material partially contained within said pre-molded body of plastic, said body of thermally conductive material having first and second opposed major faces and a retaining flange extending inward and at least partially defining the edge surfaces thereof connected to said lead frame with said first major face in thermal contact with said electronic semiconductor circuit and said second major face substantially parallel with and adjacent one of said opposed sides of said package extending to the surface of the package body.

31. A structure as in claim 30, wherein a routing board is used to interconnect the semiconductor circuit.

32. A structure as in claim 30, wherein lead frame and die paddle or rerouting board support pin holes provide thermal transfer paths to lead frame and die paddle or rerouting board.

33. A structure as in claim 30, wherein at least one transmissive lens is formed in the seal lid to provide path for ultra violet, infrared, or optical rays to penetrate from the pre-molded package plastic body to the external environment.

34. A structure for pre-molding electronic circuit packages components comprising:

(a) a lead frame defining a semiconductor circuit location having terminal leads extending therefrom; and

(b) an ejection or transfer mold with lead frame support pins providing the lead frame and die paddle or rerouting board mechanical support to prevent mold flash or bleed on or into the interconnection surface, die attach, or pre-mold cavity.