Electronic packages for flip chip devices

• US 10,269,687 B2
• Filed: 02/16/2017
• Issued: 04/23/2019
• Est. Priority Date: 02/24/2015
• Status: Active Grant

• Current Assignee: Navitas Semiconductor Limited (Navitas Semiconductor Corp.)
• Original Assignee: Navitas Semiconductor, Inc.
• Inventors: Kinzer, Daniel Marvin
• Primary Examiner(s): Naraghi, Ali
• Application Number:
  US15/434,956
• Publication Number:
  US 20170162483A1
• Time in Patent Office: 796 Days
• Field of Search: None
• CPC Class Codes: H01L 21/4825 Connection or disconnection of other leads to or from flat leads, e.g. wires, bumps, other flat leads
• CPC Class Codes: H01L 21/4828 Etching etching for cleaning without patterning H01L21/4835
• CPC Class Codes: H01L 21/4842 Mechanical treatment, e.g. punching, cutting, deforming, cold welding
• CPC Class Codes: H01L 21/4882 Assembly of heatsink parts
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 21/565 Moulds
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/371 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 2224/37124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/37147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/37599 Material
• CPC Class Codes: H01L 2224/40245 the item being metallic
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 2224/73255 Bump and strap connectors
• CPC Class Codes: H01L 2224/83801 Soldering or alloying
• CPC Class Codes: H01L 2224/8385 using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 23/3114 the device being a chip scale package, e.g. CSP
• CPC Class Codes: H01L 23/3135 Double encapsulation or coating and encapsulation
• CPC Class Codes: H01L 23/4951 Chip-on-leads or leads-on-chip techniques, i.e. inner lead fingers being used as die pad
• CPC Class Codes: H01L 23/4952 : the additional leads being a bump or a wire
• CPC Class Codes: H01L 23/49524 : the additional leads being a tape carrier or flat leads
• CPC Class Codes: H01L 23/49548 : Cross section geometry H01L23/49562 takes precedence
• CPC Class Codes: H01L 23/49562 : for devices being provided for in H01L29/00
• CPC Class Codes: H01L 23/49568 : specifically adapted to facilitate heat dissipation
• CPC Class Codes: H01L 23/49575 : Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 23/49586 : Insulating layers on lead frames
• CPC Class Codes: H01L 29/2003 : Nitride compounds
• CPC Class Codes: H01L 29/41758 : for lateral devices with structured layout for source or drain region, i.e. the source or drain region having cellular, interdigitated or ring structure or being curved or angular H01L29/41733 - H01L29/4175 take precedence
• CPC Class Codes: H01L 29/7787 : with wide bandgap charge-carrier supplying layer, e.g. direct single heterostructure MODFET
• 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 2924/18161 : of a flip chip

Abstract

Electronic packages are formed from a generally planar leadframe having a plurality of leads coupled to a GaN-based semiconductor device, and are encased in an encapsulant. The plurality of leads are interdigitated and are at different voltage potentials.

Claims

1. An electronic package comprising:

a leadframe having a thickness extending from a top surface of the leadframe to a bottom surface of the leadframe and comprising;

a first terminal having a plurality of first terminal fingers extending therefrom and a second terminal having a plurality of second terminal fingers extending therefrom wherein the plurality of first terminal fingers are interdigitated with the plurality of second terminal fingers;

wherein the first terminal and the second terminal have a first thickness extending from the top surface of the leadframe to the bottom surface of the leadframe; and

wherein the plurality of first terminal fingers and the plurality of second terminal fingers have a second thickness extending from the top surface of the leadframe to an intermediate plane that is located between the top surface and the bottom surface of the leadframe;

a GaN-based die electrically coupled to the top surface of the leadframe, and including a source pad having a plurality of source fingers and a drain pad having a plurality of drain fingers wherein the plurality of source fingers are interdigitated with the plurality of drain fingers;

a plurality of interconnects disposed between the GaN-based die and the top surface of the leadframe and configured to provide electrical continuity between the plurality of first terminal fingers and the plurality of drain fingers, and between the plurality of second terminal fingers and the plurality of source fingers, respectively;

one or more channels formed in the bottom surface of the leadframe to a depth of at least the intermediate plane; and

an encapsulant encapsulating the GaN-based die and at least a portion of the leadframe, the encapsulant extending from at least a top surface of the GaN-based die to the bottom surface of the leadframe.

2. The electronic package of claim 1 wherein there are two channels formed in the bottom surface of the leadframe.

3. The electronic package of claim 1 further comprising a third terminal having at least one third terminal finger.

4. The electronic package of claim 1 wherein the first terminal is an elongated bar and the plurality of first terminal fingers are attached along a length of the bar and extend outward away from the first terminal.

5. The electronic package of claim 1 wherein the second terminal is an elongated bar and the plurality of second terminal fingers are attached along a length of the bar and extend outward away from the second terminal.

6. The electronic package of claim 1 wherein an exposed portion of the first terminal is separated from an exposed portion of the second terminal by a distance of at least 1 millimeter.

7. An electronic package comprising:

a leadframe having a first thickness extending from a top surface of the leadframe to an intermediate plane and a second thickness extending from a top surface of the leadframe to a bottom surface of the leadframe, the leadframe including a first portion electrically isolated from a second portion wherein the first portion has a first terminal that is the second thickness and at least one lead extending therefrom that is the first thickness, and the second portion has a second terminal that is the second thickness and at least one lead extending therefrom that is the first thickness;

a GaN-based die electrically coupled to the top surface of the leadframe, and including a source pad electrically coupled to the first portion of the leadframe and a drain pad electrically coupled to the second portion of the leadframe;

a first encapsulant encapsulating the GaN-based die and at least a portion of the leadframe, the encapsulant extending from at least a top surface of the GaN-based die to the bottom surface of the leadframe; and

a second encapsulant having a thickness extending from the bottom surface of the leadframe to the intermediate plane and extending across at least a portion of the first portion and the second portion of the leadframe.

8. The electronic package of claim 7 wherein the first portion includes an elongated bar and a plurality of first terminal fingers attached along a length of the bar extending outward away from the elongated bar.

9. The electronic package of claim 7 wherein the second portion includes an elongated bar and a plurality of second terminal fingers attached along a length of the bar extending outward away from the elongated bar.

10. An electronic package comprising:

a leadframe including a first terminal having a plurality of first terminal fingers extending therefrom and a second terminal having a plurality of second terminal fingers extending therefrom wherein the plurality of first terminal fingers are interdigitated with the plurality of second terminal fingers;

a GaN-based die electrically coupled to a top surface of the leadframe and including a source pad having a plurality of source fingers and a drain pad having a plurality of drain fingers wherein the plurality of source fingers are interdigitated with the plurality of drain fingers;

a plurality of interconnects disposed between the GaN-based die and the leadframe and configured to provide electrical continuity between the plurality of first terminal fingers and the plurality of drain fingers, and between the plurality of second terminal fingers and the plurality of source fingers, respectively;

an encapsulant encapsulating the GaN-based die and extending from at least a top surface of the GaN-based die to a bottom surface of the leadframe; and

a dielectric layer disposed on a portion of a bottom surface of the electronic package at least partially defining one or more electronic package interconnects.

11. The electronic package of claim 10 wherein the dielectric layer is a soldermask material.

12. The electronic package of claim 10 wherein the first terminal is an elongated bar and the plurality of first terminal fingers are attached along a length of the bar and extend outward away from the first terminal in a direction of the second terminal.

13. The electronic package of claim 10 wherein the second terminal is an elongated bar and the plurality of second terminal fingers are attached along a length of the bar and extend outward away from the second terminal in a direction of the first terminal.

14. The electronic package of claim 10 wherein the encapsulant extends to the bottom surface of the electronic package and is disposed within gaps between the plurality of first terminal fingers and the plurality of second terminal fingers.

15. An electronic package comprising:

a leadframe including a first portion electrically isolated from a second portion;

a GaN-based die electrically coupled to a top surface of the leadframe and including a source pad and a drain pad;

a plurality of interconnects disposed between the GaN-based die and the leadframe and configured to provide electrical continuity between the first portion of the leadframe and the drain pad, and between the second portion of the leadframe and the source pad, respectively;

an encapsulant encapsulating the GaN-based die and extending from at least a top surface of the GaN-based die to a bottom surface of the leadframe; and

a dielectric layer disposed on a portion of a bottom surface of the electronic package at least partially defining one or more electronic package interconnects.

16. The electronic package of claim 15 wherein the dielectric layer is a soldermask material.

17. The electronic package of claim 15 wherein the first portion includes an elongated bar and a plurality of first fingers attached along a length of the elongated bar and extending outward away from the elongated bar.

18. The electronic package of claim 15 wherein the second portion includes an elongated bar and a plurality of second fingers attached along a length of the elongated bar and extending outward away from the elongated bar.

19. The electronic package of claim 15 wherein the encapsulant extends to the bottom surface of the electronic package and is disposed within gaps between the first portion and the second portion.

20. The electronic package of claim 15 wherein the leadframe includes a third portion that is electrically isolated from the first and the second portions.