Ball grid array (BGA) integrated circuit packages

• US 5,796,170 A
• Filed: 02/15/1996
• Issued: 08/18/1998
• Est. Priority Date: 02/15/1996
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Marcantonio, Gabriel
• Primary Examiner(s): Jackson, Jerome
• Assistant Examiner(s): CLARK, SHEILA V
• Application Number:
  US08/601,667
• Time in Patent Office: 915 Days
• Field of Search: 257/691, 257/738, 257/659, 257/780, 257/781, 257/786, 257/706, 257/779, 257/698, 257/693
• US Class Current: 257/786
• CPC Class Codes: H01L 2224/05599 Material
• 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 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49109 outside the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/24 solid or gel at the normal operating temperature of the device H01L23/3135 takes precedence
• CPC Class Codes: H01L 23/3672 Foil-like cooling fins or heat sinks being part of lead-frames H01L23/49568
• CPC Class Codes: H01L 23/3675 characterised by the shape of the housing
• CPC Class Codes: H01L 23/49816 Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 23/49827 Via connections through the substrates, e.g. pins going through the substrate, coaxial cables H01L23/49822, H01L23/49833, H01L23/4985, H01L23/49861 take precedence
• CPC Class Codes: H01L 23/49838 Geometry or layout
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• 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 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01076 : Osmium [Os]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/1433 : Application-specific integrated circuit [ASIC]
• CPC Class Codes: H01L 2924/15153 : the die mounting substrate comprising a recess for hosting the device
• CPC Class Codes: H01L 2924/15165 : Monolayer substrate
• CPC Class Codes: H01L 2924/1517 : Multilayer substrate
• 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 2924/16195 : Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H05K 1/0218 : by printed shielding conductors, ground planes or power plane H05K1/0236 takes precedence

Abstract

An improved ball grid array (BGA) package having EMI shielding is provided. In a BGA package a thermally conductive heat spreader provided by a conductive layer, and an electrical interconnection is provided between the electrically conductive heat spreader and solder balls of the array, for example by plated through holes extending through the dielectric body of the package. Thus in use of the package, when contacts are made from the array of solder balls to a corresponding array of contact areas of a substrate, a ground connection is simultaneously provided to the heat spreader through the solder balls. For example, one or more conductive contacts on the substrate may be connected to a ground plane of the substrate, and a corresponding solder balls of the package are interconnected to the heat spreader. Beneficially, the ground connection is provided by external rows of solder balls of the array extending around sides of package, or by clusters of solder balls surrounding balls for carrying signals. Thus by providing integral ground connections, the heat spreader of the BGA package functions also a Faraday shield providing for improved shielding of electromagnetic interference.

Claims

1. A ball grid array package for an integrated circuit comprising a dielectric body, a heat spreader disposed on one side of the dielectric body comprising a layer of a thermally conductive material, the heat spreader also being electrically conductive,

the dielectric body surrounding a die attach area on the heatspreader, and providing a plurality of bond pads for wirebonding of the integrated circuit, and interconnection from the bond pads through the dielectric body to a plurality of solder balls of a ball arid array provided on the other side of the dielectric body, and

a conductive interconnection provided between the heat spreader and selected solder balls of the ball grid array, for providing a ground connection to the heatstreader through the solder balls.

3. A BGA package according to claim 1 wherein selected solder balls comprise an external row of solder balls of the array extending along sides of the array of solder balls.

4. A BGA package according to claim 1 wherein selected solder balls providing for grounding of the heater heat spreader comprise a cluster of solder balls surrounding solder balls for carrying signals.

5. A BGA package according to claim 1 wherein the conductive interconnection comprises a plated through hole extending through the dielectric body and interconnecting the heat spreader and selected solder balls of the array.

6. A BGA package according to claim 1 wherein the conductive interconnection comprises a conductive pin extending through the dielectric body and interconnecting the heat spreader and selected solder balls of the array.

7. A BGA package according to claim 1 wherein the conductive interconnection comprises a side plated interconnection extending over a surface of the dielectric body to interconnect the heat spreader and selected solder balls of the array.

8. A BGA package according to claim 1 wherein the heat spreader comprises a layer of copper or copper alloy extending over a surface of the package.

2. A ball grid array package for an integrated circuit comprising:

a heat spreader comprising a thermally and electrically conductive material;

a body of the package for enclosing an integrated circuit chip in thermal contact with the heat spreader disposed on one side of the body;

and disposed on an opposite side of the body a metallization layer defining conductive leads on which is disposed an array of solder balls, conductive interconnections extending through the body from solder balls of the array to lead bond pads for the integrated circuit;

wherein the improvement comprises a conductive interconnection extending between the heat spreader through the body to selected solder balls the array, for interconnection of the heat spreader to a ground connection through the array of solder balls.

9. An assembly of a ball grid array package, an integrated circuit, and a substrate comprising a conductive layer providing a ground plane, comprising:

the ball arid array package comprising a dielectric body, an electrically conductive heatspreader disposed on one side of the body, and an array of solder balls disposed on an opposite side of the body, the integrated circuit enclosed by the heatspreader and the dielectric body of the ball grid array package;

and the heat spreader being in thermal contact with the integrated circuit;

conductive interconnections extending from contact pads of the integrated circuit though conductive leads extending through the dielectric body of the ball grid array package to corresponding individual solder balls of an array of solder balls;

each solder ball being conductively interconnected with a corresponding one of an array of bond pads provided on the substrate,

and the heat spreader being interconnected through conductive interconnections to selected solder balls connected to the ground plane of the substrate.

10. An assembly according to claim 9 wherein the conductive interconnections between the heat spreader and the selected solder balls comprise plated through holes extending through the dielectric body.

11. An assembly according to claim 9 wherein the conductive interconnections between the heat spreader and the selected solder balls comprise conductive pins extending through the dielectric body.

12. An assembly according to claim 9 wherein the conductive interconnection between the heat spreader and the selected solder balls comprise conductive side plated regions of the dielectric body of the package.

13. A ball grid array package for an integrated circuit comprising a dielectric body, an array of solder balls of a ball grid array disposed on one side of the dielectric body, and a heat spreader comprising a layer of a thermally conductive material disposed on an opposite side of the dielectric body, the heat spreader also being electrically conductive,

conductive interconnections extending through the dielectric body from solder balls of the ball grid array to bond pads for interconnecting an integrated circuit within the package, and

other conductive interconnections provided between the heat spreader and selected other solder balls of the ball grid array, for providing a ground connection to the heatspreader, the selected other solder balls comprising rows of solder balls around external edges of the ball grid array package surrounding solder balls for interconnection to the integrated circuit.

14. A ball grid array package for an integrated circuit comprising a dielectric body, an array of solder balls of a ball grid array disposed on one side of the dielectric body, and a heat spreader comprising a layer of a thermally conductive material disposed on an opposite side of the dielectric body, the heat spreader also being electrically conductive,

conductive interconnections extending through the dielectric body from solder balls of the ball grid array to bond pads for interconnecting an integrated circuit within the package, and

other conductive interconnections provided between the heat spreader and selected other solder balls of the ball grid array, for providing a ground connection to the heatspreader, the selected other solder balls comprising a cluster of solder balls arranged around solder balls for carrying signals to the integrated circuit.