POWER MODULE AND FABRICATION METHOD FOR THE SAME

• US 20160141231A1
• Filed: 01/21/2016
• Published: 05/19/2016
• Est. Priority Date: 07/22/2013
• Status: Active Grant

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: YOSHIHARA, Katsuhiko, SAITO, Masao
• Granted Patent: US 9,721,875 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/4842 Mechanical treatment, e.g. punching, cutting, deforming, cold welding
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 23/3135 Double encapsulation or coating and encapsulation
• CPC Class Codes: H01L 23/36 Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks H01L23/28, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence; heating H01L23/345
• CPC Class Codes: H01L 23/42 Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
• CPC Class Codes: H01L 23/49548 Cross section geometry H01L23/49562 takes precedence
• CPC Class Codes: H01L 23/49551 characterised by bent parts
• CPC Class Codes: H01L 23/49562 for devices being provided for in H01L29/00
• 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 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13055 Insulated gate bipolar transistor [IGBT]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Abstract

A power module includes: an insulating layer; a leadframe disposed on the insulating layer; a semiconductor chip disposed on the leadframe; and a mold resin formed so as to cover the semiconductor chip and at least a part of the metal layer, wherein a groove into which a part of the insulating layer is inserted is formed on a surface of the leadframe facing the insulating layer. Accordingly, there can be provided the power module with improved reliability so that the insulating layer and the leadframe may be hardly deviated from each other even if external force is applied thereon; and a fabrication method for such a power module.

Claims

1. A power module comprising:

an insulating layer;

a metal layer disposed on the insulating layer;

a semiconductor chip disposed on the metal layer; and

a mold resin formed so as to cover the semiconductor chip and at least a part of the metal layer, wherein

a groove into which a part of the insulating layer is inserted is formed on a surface of the metal layer facing the insulating layer.

2. The power module according to claim 1, wherein

a plurality of the groove are formed outside a region of the metal layer opposite to the semiconductor chip.

3. The power module according to claim 2, wherein

the region is a region where an angle between a line and a flat surface of the metal layer is equal to or less than 45 degrees, the line connecting between an edge part of the semiconductor chip and an edge part of the groove nearest to the semiconductor chip among the plurality of the grooves.

4. The power module according to claim 2, wherein

the plurality of the groove are formed only outside a region of the metal layer opposite to the semiconductor chip.

5. The power module according to claim 1, wherein:

a cross-sectional shape of the groove is at least one shape selected from the group consist of a rectangle shape, a semicircle shape, a semi-ellipse shape, triangular shape, and a wedge shape; and

a depth of the groove is shallower than a half of a thickness of the metal layer.

6. The power module according to claim 1, wherein

the groove is formed along in one direction or is formed in a lattice-like shape.

7. The power module according to claim 1, wherein

a surface roughening process is applied on a surface of the metal layer facing the insulating layer.

8. The power module according to claim 1, wherein

the insulating layer is formed of a material softer than the metal layer.

9. The power module according to claim 8, wherein

a hardness of the insulating layer is softer than A40 in durometer hardness.

10. The power module according to claim 1, wherein

the insulating layer is formed of an organic material.

11. The power module according to claim 1, wherein

the insulating layer is formed of a silicone based resin.

12. The power module according to claim 1, wherein

the insulating layer is filled up with a high thermally-conductive filler.

13. The power module according to claim 12, wherein

the filler is at least one selected from the group consist of aluminium oxide, silicon oxide, aluminum nitride, silicon nitride, boron nitride, beryllia, and magnesia.

14. The power module according to claim 12, wherein

the mold resin is formed so as to cover at least a part of a side surface of the insulating layer and a corner portion of the metal layer.

15. The power module according to claim 14, wherein

an edge part of the insulating layer is intervened between the mold resin and the metal layer.

16. The power module according to claim 1, wherein

the mold resin is formed so as to cover at least a part of a side surface of the insulating layer and a corner portion of the metal layer.

17. The power module according to claim 16, wherein:

the semiconductor chip is formed of one selected from the group consist of an SiC based power device, a GaN based power device, and an AlN based power device; and

a current change rate di/dt thereof is larger than 3×

10⁸ (A/s).

18. The power module according to claim 1, wherein

the power module is formed as any one selected from the group consist of 1-in-1 module, 2-in-1 module, 4-in-1 module, and 6-in-1 module.

19. A fabrication method for a power module comprising:

forming a groove on a bottom surface of a leadframe;

bonding a semiconductor chip to the leadframe with a conductive bonding material;

electrically connecting the semiconductor chip and the leadframe to each other using a connecting member;

disposing the leadframe on a metallic mold and then forming an insulating layer on a bottom surface of the leadframe, the insulating layer formed so as to be inserted into the bottom surface of the leadframe; and

after curing the insulating layer, closing the metallic mold, and then pouring a mold resin therein in order to mold the leadframe, the conductive bonding material, the semiconductor chip, and the connecting member.

20. The fabrication method for a power module according to claim 19, wherein

the step of forming the insulating layer on the bottom surface of the leadframe comprises forming the insulating layer so as to cover a corner portion of the leadframe.

21. A fabrication method for a power module comprising:

forming a groove on a bottom surface of a leadframe;

bonding a semiconductor chip to the leadframe with a conductive bonding material;

electrically connect the semiconductor chip and the leadframe to each other using a connecting member;

disposing the leadframe on a metallic mold and then forming an insulating layer on a bottom surface of the leadframe; and

after curing the insulating layer, closing the metallic mold, and then pouring a mold resin therein in order to mold the leadframe, the conductive bonding material, the semiconductor chip, and the connecting member, wherein

the step of forming the insulating layer on the bottom surface of the leadframe comprises forming so that a surface of the mold resin and a surface of the leadframe are flush with each other at a corner portion of the leadframe, and then forming the insulating layer on the surface of the mold resin and the surface of the leadframe which are flush with each other.