Lead frame used for the fabrication of semiconductor packages and semiconductor package fabricated using the same

• US 6,437,427 B1
• Filed: 09/08/1999
• Issued: 08/20/2002
• Est. Priority Date: 09/15/1998
• Status: Expired due to Term

• Current Assignee: Amkor Technology Singapore Holding Pte., Ltd. (Amkor Technology Incorporated)
• Original Assignee: Amkor Technology Incorporated
• Inventors: Choi, Yeon Ho
• Primary Examiner(s): Flynn, Nathan J.
• Assistant Examiner(s): Sefer, Ahmed N.
• Application Number:
  US09/391,792
• Time in Patent Office: 1,077 Days
• Field of Search: 257/670, 257/676, 257/666, 257/684, 257/696, 257/712, 257/713, 257/706, 257/707, 257/671, 257/672, 257/675, 257/678, 257/698, 257/692
• US Class Current: 257/666
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/27013 for holding or confining the layer connector, e.g. solder flow barrier
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die 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 2224/49109 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 2224/83051 Forming additional members, e.g. dam structures
• CPC Class Codes: H01L 2224/83385 Shape, e.g. interlocking features
• CPC Class Codes: H01L 23/49503 characterised by the die pad
• CPC Class Codes: H01L 24/32 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 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 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01083 : Bismuth [Bi]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 2924/351 : Thermal stress

Abstract

A lead frame for a semiconductor package including a rectangular lead frame body having a central opening, a plurality of leads arranged at and along each of two or four facing sides of the lead frame body, the leads extending in flush with the lead frame body, and a semiconductor chip mounting plate positioned on a plane not flush with a plane, where the leads are positioned, the semiconductor chip mounting plate being supported by down-set tie bars and provided with at least one groove having a rectangular ring shape while serving to prevent a penetration of moisture and to provide an increased coupling strength for the semiconductor chip mounting plate, the semiconductor chip mounting plate also serving as a heat sink. A ground bridge bar having a rectangular ring shape is arranged between the semiconductor chip mounting plate and the leads and supported by another tie bars. By virtue of the bridge bar, the length of bonding wires is reduced, thereby eliminating the possibility of the bonding wires to be short-circuited. A lead frame having a double down-set structure is also provided. By virtue of the double down-set structure, it is possible to increase the size of the semiconductor chip mounting plate, thereby achieving an improvement in the heat discharge effect.

Claims

1. A lead frame for a semiconductor package comprising:

a rectangular lead frame body having a central opening;

a plurality of leads arranged at and along each of two or four facing sides of said lead frame body, said leads extending in flush with said lead frame body;

a semiconductor chip mounting plate positioned on a plane not flush with a plane where said leads are positioned, said semiconductor chip mounting plate being supported by down-set tie bars and provided at a surface thereof, on which a semiconductor chip is to be mounted, with at least one groove having a rectangular ring shape; and

a bridge bar arranged between said semiconductor chip mounting plate and said leads and supported by first tie bars, said bridge bar having a rectangular ring shape, wherein said bridge bar is supported by said first tie bars at four corners thereof, respectively, and said semiconductor chip mounting plate is supported by said down-set tie bars at four comers thereof, respectively.

3. The lead frame in accordance with claim 1 or 2, wherein said bridge bar is positioned on a plane flush with said plane of said leads.

4. The lead frame in accordance with claim 1 or 2, wherein said bridge bar is positioned on a plane not flush with said plane of said leads and said plane of said semiconductor chip mounting plate.

5. The lead frame in accordance with claim 1, wherein the semiconductor chip mounting plate includes a plurality of the grooves having the rectangular ring shape, with the grooves being concentric.

2. A lead frame for a semiconductor package comprising:

a rectangular lead frame body having a central opening;

a plurality of leads arranged at and along each of two or four facing sides of said lead frame body, said leads extending in flush with said lead frame body;

a semiconductor chip mounting plate positioned on a plane not flush with a plane where said leads are positioned, said semiconductor chip mounting plate being supported by down-set tie bars and provided at a surface thereof, on which a semiconductor chip is to be mounted, with at least one groove having a rectangular ring shape; and

a bridge bar arranged between said semiconductor chip mounting plate and said leads and supported by first tie bars, said bridge bar having a rectangular ring shape, wherein said bridge bar is supported by said first tie bars at four comers thereof, respectively, and said semiconductor chip mounting plate is supported by said down-set tie bars at four sides thereof, respectively.

6. The lead frame in accordance with claim 2, wherein the semiconductor chip mounting plate includes a plurality of the grooves having the rectangular ring shape, with the grooves being concentric.

20. The semiconductor package in accordance with claim 6, wherein the bridge bar is electrically connected to at least one of the leads.

21. The semiconductor package in accordance with claim 20, wherein the bridge bar is vertically between the leads and the semiconductor chip mounting plate.

22. The lead frame in accordance with claim 20, wherein said bridge bar is positioned on a plane flush with a plane of said leads.

7. A lead frame for a semiconductor package comprising:

a rectangular lead frame body having a central opening;

a plurality of leads arranged at and along each of two or four facing sides of said lead frame body, said leads extending in flush with said lead frame body;

a semiconductor chip mounting plate positioned on a plane not flush with a plane where said leads are positioned, said semiconductor chip mounting plate being supported by down-set tie bars and provided at a surface thereof, on which a semiconductor chip is to be mounted, with at least one groove having a rectangular ring shape; and

a bridge bar arranged between said semiconductor chip mounting plate and said leads and supported by first tie bars, said bridge bar having a rectangular ring shape, wherein each of said down-set tie bars, which extends from said bridge bar to support said semiconductor chip mounting plate, extends inwardly to a portion of said semiconductor chip mounting plate between an edge of said semiconductor chip mounting plate and said groove.

8. A semiconductor package comprising:

a lead frame body having a plurality of leads arranged at and along each of two or four facing sides of said lead frame body, and a semiconductor chip mounting plate positioned on a plane not flush with a plane where said leads are positioned, said semiconductor chip mounting plate being supported by down-set tie bars and provided at a surface thereof, on which a semiconductor chip is to be mounted, with at least one groove having a rectangular ring shape, said semiconductor chip mounting plate also serving as a heat sink;

said semiconductor chip mounted on said semiconductor chip mounting plate inside said groove and electrically connected to said leads;

a resin seal encapsulating said leads and said semiconductor chip without encapsulating a lower surface of said semiconductor chip mounting plate; and

a bridge bar arranged between said semiconductor chip mounting plate and said leads and supported by first tie bars, said bridge bar having a rectangular ring shape, wherein each of said down-set tie bars, which extends from said bridge bar to support said semiconductor chip mounting plate, extends inwardly to a portion of said semiconductor chip mounting plate between an edge of said semiconductor chip mounting plate and said groove.

9. A semiconductor package comprising:

a lead frame body having a plurality of leads arranged at and along each of two or four facing sides of said lead frame body, and a semiconductor chip mounting plate positioned on a plane not flush with a plane where said leads are positioned, said semiconductor chip mounting plate being supported by down-set tie bars and provided at a surface thereof, on which a semiconductor chip is to be mounted, with at least one groove having a rectangular ring shape, said semiconductor chip mounting plate also serving as a heat sink;

said semiconductor chip mounted on said semiconductor chip mounting plate inside said groove and electrically connected to said leads;

a resin seal encapsulating said leads and said semiconductor chip without encapsulating a lower surface of said semiconductor chip mounting plate; and

a bridge bar arranged between said semiconductor chip mounting plate and said leads and supported by first tie bars, said bridge bar having a rectangular ring shape, wherein said bridge bar is supported by said first tie bars at four comers thereof, respectively, and said semiconductor chip mounting plate is supported by said down-set tie bars at four comers thereof, respectively.

10. A semiconductor package comprising:

a lead frame body having a plurality of leads arranged at and along each of two or four facing sides of said lead frame body, and a semiconductor chip mounting plate positioned on a plane not flush with a plane where said leads are positioned, said semiconductor chip mounting plate being supported by down-set tie bars and provided at a surface thereof, on which a semiconductor chip is to be mounted, with at least one groove having a rectangular ring shape, said semiconductor chip mounting plate also serving as a heat sink;

said semiconductor chip mounted on said semiconductor chip mounting plate inside said groove and electrically connected to said leads;

a resin seal encapsulating said leads and said semiconductor chip without encapsulating a lower surface of said semiconductor chip mounting plate; and

a bridge bar arranged between said semiconductor chip mounting plate and said leads and supported by first tie bars, said bridge bar having a rectangular ring shape, wherein said bridge bar is supported by said first tie bars at four comers thereof, respectively, and said semiconductor chip mounting plate is supported by said down-set tie bars at four sides thereof, respectively.

11. The semiconductor package in accordance with claim 8, 9, or 10, wherein the semiconductor chip mounting plate includes a plurality of the grooves having the rectangular ring shape, with the grooves being concentric.

12. The semiconductor package in accordance with claim 8, 9, or 10, wherein said bridge bar is positioned on a plane flush with said plane of said leads.

13. The semiconductor package in accordance with claim 8, 9, or 10, wherein said bridge bar is positioned on a plane not flush with said plane of said leads and not flush with said plane of said semiconductor chip mounting plate.

14. The semiconductor package in accordance with claim 8, 9, or 10, wherein the bridge bar is electrically connected to the semiconductor chip.

15. A semiconductor package comprising:

a leadframe comprising a metal semiconductor chip mounting plate having a first surface, an opposite second surface, and a plurality of metal leads extending toward said semiconductor chip mounting plate, wherein the first surface has at least one groove therein extending in a ring about a peripheral portion of the first surface;

a semiconductor chip mounted on the fist surface of the semiconductor chip mounting plate inside said groove ring and electrically connected to said leads;

a bridge bar arranged between said semiconductor chip mounting plate and said leads, said bridge bar fully surrounding said semiconductor chip mounting plate and being integrally connected to the semiconductor chip mounting plate; and

a resin seal covering said leads, said semiconductor chip, and said first surface of the semiconductor chip mounting plate while exposing the second surface of said semiconductor chip mounting plate.

16. The semiconductor package in accordance with claim 15, wherein the bridge bar is vertically between the leads and the semiconductor chip mounting plate.

17. The semiconductor package in accordance with claim 15, wherein the first surface of the semiconductor chip mounting plate includes a plurality of the grooves, with the grooves being concentric and the semiconductor chip being inside said plurality of the grooves.

18. The semiconductor package in accordance with claim 15, wherein the bridge bar is electrically connected to the chip.

19. The semiconductor package in accordance with claim 18, wherein the bridge bar is electrically connected to at least one of the leads.

23. A semiconductor package comprising:

a leadframe comprising a metal semiconductor chip mounting plate having a first surface, an opposite second surface, and a plurality of metal leads extending toward said semiconductor chip mounting plate;

a semiconductor chip mounted on the first surface of the semiconductor chip mounting plate and electrically connected to said leads;

a bridge bar arranged between said semiconductor chip mounting plate and said leads, said bridge bar filly surrounding said semiconductor chip mounting plate and being integrally connected to the semiconductor chip mounting plate; and

a resin seal covering said leads, said semiconductor chip, and said first surface of the semiconductor chip mounting plate while exposing the second surface of said semiconductor chip mounting plate.

24. The semiconductor package in accordance with claim 23, wherein the bridge bar is electrically connected to the chip.

25. The semiconductor package in accordance with claim 24, wherein the bridge bar is electrically connected to at least one of the leads.

26. The semiconductor package in accordance with claim 23, wherein the bridge bar is electrically connected to at least one of the leads.

27. The semiconductor package in accordance with claim 23, wherein the bridge bar is vertically between the leads and the semiconductor chip mounting plate, and is electrically connected to at least one of the leads.

28. The lead frame in accordance with claim 23, wherein said bridge bar is positioned on a plane flush with a plane of said leads, and is electrically connected to at least one of the leads.