Power Module with Directly Attached Thermally Conductive Structures

• US 20130285234A1
• Filed: 04/30/2012
• Published: 10/31/2013
• Est. Priority Date: 04/30/2012
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Uhlemann, Andre, Herbrandt, Alexander, Broermann, Frank
• Granted Patent: US 8,872,332 B2
• Time in Patent Office: Days
• US Class Current: 257/712
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/4813 Connecting within a semiconductor or solid-state body, i.e. fly wire, bridge wire
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• CPC Class Codes: H01L 23/3677 Wire-like or pin-like cooling fins or heat sinks
• CPC Class Codes: H01L 23/3735 Laminates or multilayers, e.g. direct bond copper ceramic substrates
• CPC Class Codes: H01L 23/4006 with bolts or screws
• CPC Class Codes: H01L 23/4334 Auxiliary members in encapsulations H01L23/49568 takes precedence
• CPC Class Codes: H01L 23/467 by flowing gases, e.g. air H01L23/473 takes precedence
• CPC Class Codes: H01L 23/473 by flowing liquids H01L23/4332, H01L23/4338 take precedence
• CPC Class Codes: H01L 25/072 the devices being arranged next to each other
• 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 2924/00014 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 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13055 Insulated gate bipolar transistor [IGBT]

Abstract

A power module includes a substrate having an electrically insulative member with opposing first and second metallized sides and one or more semiconductor die attached to the first metallized side of the substrate. A plurality of thermally conductive structures are laterally spaced apart from one another and individually attached directly to the second metallized side of the substrate so that the plurality of thermally conductive structures extend outward from the second metallized side.

Claims

1. A power module, comprising:

a substrate comprising an electrically insulative member with opposing first and second metallized sides;

one or more semiconductor die attached to the first metallized side of the substrate; and

a plurality of thermally conductive structures laterally spaced apart from one another and individually attached directly to the second metallized side of the substrate so that the plurality of thermally conductive structures extend outward from the second metallized side.

2. A power module according to claim 1, wherein each thermally conductive structure is individually welded to the second metallized side of the substrate.

3. A power module according to claim 1, wherein each thermally conductive structure has a length measured from the second metallized side of the substrate extending outward which ranges from 0.5 mm to 5 cm and a width which ranges from 0.1 mm to 3 mm.

4. A power module according to claim 3, wherein the length of one or more of the plurality of thermally conductive structures is greater than the width.

5. A power module according to claim 3, wherein the width of one or more of the plurality of thermally conductive structures is greater than the length.

6. A power module according to claim 3, wherein the plurality of thermally conductive structures have at least one of variable lengths and variable widths.

7. A power module according to claim 1, wherein each thermally conductive structure has a cylindrical, columnar or hexagonal shape.

8. A power module according to claim 1, wherein a density of the plurality of thermally conductive structures is higher in a region of the second metallized side of the substrate corresponding to where each semiconductor die is attached to the first metallized side and lower elsewhere.

9. A power module according to claim 1, wherein the substrate is a direct copper bonded substrate, a direct aluminum bonded substrate, an active metal brazed substrate, or a substrate with the first metallized side comprising copper and the second metallized side comprising aluminum.

10. A power module according to claim 1, wherein the second metallized side and the plurality of thermally conductive structures each comprise a copper alloy.

11. A power module according to claim 1, wherein the second metallized side and the plurality of thermally conductive structures each comprise an aluminum alloy.

12. A power module according to claim 1, wherein the plurality of thermally conductive structures are individually attached directly to the second metallized side of the substrate in rows and columns in an aligned manner.

13. A power module, comprising:

a substrate comprising an electrically insulative member with opposing first and second metallized sides;

one or more semiconductor die attached to the first metallized side of the substrate;

a housing covering the one or more semiconductor die; and

a plurality of thermally conductive structures laterally spaced apart from one another and individually attached directly to the second metallized side of the substrate so that the plurality of thermally conductive structures extend outward from the second metallized side.

14. A power module according to claim 13, further comprising a cooler having a solid portion attached to the second metallized side of the substrate and a cavity so that the plurality of thermally conductive structures extend into the cavity and are laterally surrounded by the cooler.

15. A power module according to claim 14, further comprising a sealing ring seated in a recess formed in the cooler, the sealing ring providing a seal between the cooler and the second metallized side of the substrate.

16. A power module according to claim 14, wherein each thermally conductive structure is individually welded to the second metallized side of the substrate.

17. A power module according to claim 13, wherein the housing is a plastic housing or a mold compound.

18. A method of manufacturing a power module, comprising:

attaching one or more semiconductor die to a first metallized side of a substrate, the substrate comprising an electrically insulative member with the first metallized side and an opposing second metallized side; and

attaching a plurality of individual thermally conductive structures directly to the second metallized side of the substrate so that the plurality of thermally conductive structures are laterally spaced apart from one another and extend outward from the second metallized side.

19. A method according to claim 18, wherein attaching the plurality of individual thermally conductive structures directly to the second metallized side of the substrate comprises arc welding the plurality of thermally conductive structures to the second metallized side.

20. A method according to claim 19, wherein arc welding the plurality of thermally conductive structures to the second metallized side of the substrate comprises:

applying a potential to the second metallized side of the substrate;

positioning a plurality of metal structures in close proximity to the second metallized side of the substrate so that an arc ignites between each metal structure and the second metallized side, current flows from each metal structure to the second metallized side and a part of each metal structure and a part of the second metallized side melt;

placing the plurality of metal structures in direct contact with the second metallized side of the substrate after melting begins so that an adhesion bond connection is formed between each metal structure and the second metallized side; and

severing each metal structure at a distance from the second metallized side after the adhesion bond connection is formed.

21. A method according to claim 18, further comprising encasing the substrate in a mold compound except in an exposed region of the second metallized side, wherein the plurality of thermally conductive structures are directly attached to the exposed region of the second metallized side.

22. A method according to claim 21, wherein the plurality of thermally conductive structures are directly attached to the exposed region of the second metallized side after the substrate is encased in the mold compound.

23. A method according to claim 18, further comprising attaching a solid portion of a cooler to the second metallized side of the substrate so that the plurality of thermally conductive structures extend outward from the second metallized side into a cavity of the cooler and are laterally surrounded by the cooler.