Power module substrate, power module, and method for manufacturing power module substrate

Patent metadata

Field	Value
Publication number	US-2019181066-A1
Application number	US-201716095060-A
Country	US
Kind code	A1
Filing date	Apr 25, 2017
Priority date	Apr 26, 2016
Publication date	Jun 13, 2019
Grant date	—

Abstract

A power module substrate or the like including an insulating substrate with an upper surface and a lower surface, a metal plate with an upper surface and a lower surface, the lower surface facing and being bonded to the upper surface of the insulating substrate, and a first electroplating layer that partly covers the central portion of the upper surface of the metal plate. The first electroplating layer includes at least a silver layer, and the grain size of silver in the silver layer is more than or equal to the grain size of a metal in an upper surface portion of the metal plate.

First claim

1 . A power module substrate comprising:
an insulating substrate with an upper surface and a lower surface; a metal plate with an upper surface and a lower surface, the lower surface facing and being bonded to the upper surface of the insulating substrate; and a first electroplating layer on part of a central portion of the upper surface of the metal plate, wherein the first electroplating layer comprises at least a silver layer, and a grain size of silver in the silver layer is more than or equal to a grain size of a metal in an upper surface portion of the metal plate.

2 . The power module substrate according to claim 1 , wherein the first electroplating layer further comprises a nickel layer between the silver layer and the upper surface of the metal plate.

3 . The power module substrate according to claim 1 , wherein an outer perimeter of the first electroplating layer is in an uneven shape in plan view.

4 . The power module substrate according to claim 2 ,
wherein an outer perimeter of the first electroplating layer is in an uneven shape in plan view, and nickel is present in at least part of an uneven portion of the outer perimeter of the first electroplating layer.

5 . The power module substrate according to claim 1 , wherein the metal plate comprises a depression in a portion along the outer perimeter of the first electroplating layer of the upper surface.

6 . The power module substrate according to claim 5 , wherein an inner side surface of the depression is inwardly inclined or curved from an opening toward a bottom of the depression.

7 . The power module substrate according to claim 5 , wherein surface roughness of an inner side surface of the depression is more than surface roughness of the upper surface of the metal plate.

8 . The power module substrate according to claim 1 further comprising:
a heat dissipation plate with an upper surface and a lower surface, the upper surface facing and being bonded to the lower surface of the insulating substrate; and
a second electroplating layer on the lower surface of the heat dissipation plate,
wherein at least part of an outer perimeter of the second electroplating layer is apart from an outer perimeter of the lower surface of the heat dissipation plate.

9 . The power module substrate according to claim 8 , wherein the second electroplating layer comprises a nickel layer as a primary component.

10 . A power module comprising:
the power module substrate according to claim 1 ; an electronic component on the first electroplating layer of the power module substrate; and a resin layer disposed over a portion with no first electroplating layer of the upper surface of the metal plate to the electronic component.

11 . A power module comprising:
the power module substrate according to claim 8 ; an electronic component on the first electroplating layer of the power module substrate; and a resin layer disposed over the outer perimeter of the lower surface of the heat dissipation plate to the electronic component.

12 . A method for manufacturing a power module substrate comprising the steps of:
preparing an insulating mother substrate with an upper surface and a metal mother board with a lower surface and bonding the upper surface of the insulating mother substrate to the lower surface of the metal mother board by a brazing paste layer in a first step; forming a plating resist partly on an exposed surface of the metal mother board in a second step; forming an electroplating layer on portions with no plating resist of the exposed surface of the metal mother board in a third step; and removing at least some portions with no electroplating layer of the metal mother board in a fourth step.

13 . The method for manufacturing a power module substrate according to claim 12 ,
wherein the brazing paste layer is formed as a plurality of brazing paste layers independent of each other in the first step, the plating resist is formed, on the exposed surface of the metal mother board, at locations above portions between a plurality of bonding regions respectively bonded by the plurality of brazing paste layers in the second step, and dividing the metal mother board into a plurality of metal plates apart from each other by etching the metal mother board on the portions between the plurality of bonding regions in the fourth step.

14 . The power module substrate according to claim 2 , wherein an outer perimeter of the first electroplating layer is in an uneven shape in plan view.

15 . The power module substrate according to claim 2 , wherein the metal plate comprises a depression in a portion along the outer perimeter of the first electroplating layer of the upper surface.

16 . The power module substrate according to claim 3 , wherein the metal plate comprises a depression in a portion along the outer perimeter of the first electroplating layer of the upper surface.

17 . The power module substrate according to claim 2 further comprising:
a heat dissipation plate with an upper surface and a lower surface, the upper surface facing and being bonded to the lower surface of the insulating substrate; and
a second electroplating layer on the lower surface of the heat dissipation plate,
wherein at least part of an outer perimeter of the second electroplating layer is apart from an outer perimeter of the lower surface of the heat dissipation plate.

18 . The power module substrate according to claim 5 further comprising:
a heat dissipation plate with an upper surface and a lower surface, the upper surface facing and being bonded to the lower surface of the insulating substrate; and
a second electroplating layer on the lower surface of the heat dissipation plate,
wherein at least part of an outer perimeter of the second electroplating layer is apart from an outer perimeter of the lower surface of the heat dissipation plate.

19 . A power module comprising:
the power module substrate according to claim 5 ; an electronic component on the first electroplating layer of the power module substrate; and a resin layer disposed over a portion with no first electroplating layer of the upper surface of the metal plate to the electronic component.

20 . A power module comprising:
the power module substrate according to claim 18 ; an electronic component on the first electroplating layer of the power module substrate; and a resin layer disposed over the outer perimeter of the lower surface of the heat dissipation plate to the electronic component.

Assignees

• Kyocera Corp

Inventors

• Suetsugu Kenji
• Takeo Akira
• Ochiai Kensou

Classifications

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• H10W72/952

  comprising metals or metalloids, e.g. PbSn, Ag or Cu · CPC title

• H10W72/075

  of bond wires · CPC title

• H10W74/127

  characterised by arrangements for sealing or adhesion · CPC title