Power module substrate, power module substrate with heat sink, power module, method of manufacturing power module substrate, and copper member-bonding paste

Patent metadata

Field	Value
Publication number	US-10375825-B2
Application number	US-201615289453-A
Country	US
Kind code	B2
Filing date	Oct 10, 2016
Priority date	Feb 1, 2012
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

This power module substrate includes a copper plate that is formed of copper or a copper alloy and is laminated on a surface of a ceramic substrate 11; a nitride layer 31 that is formed on the surface of the ceramic substrate 11 between the copper plate and the ceramic substrate 11; and an Ag—Cu eutectic structure layer 32 having a thickness of 15 μm or less that is formed between the nitride layer and the copper plate.

First claim

The invention claimed is:

1. A power module substrate, comprising:
a ceramic substrate that is formed of AlN or Si 3 N 4 and has a first surface;
a copper plate that is formed of copper or a copper alloy and is laminated and bonded on the first surface of the ceramic substrate;
a nitride layer that contains at least one nitride of elements selected from Ti, Hf, Zr, and Nb, is formed on the first surface of the ceramic substrate between the copper plate and the ceramic substrate and the nitride layer contains one or two or more additional elements selected from In, Al, Mn and Zn; and
an Ag—Cu eutectic structure layer that has a thickness of 15 μm or less and is formed between the nitride layer and the copper plate,
wherein
the thickness of the Ag—Cu eutectic structure layer is measured by a method comprising:
obtaining a backscattered electron image of an interface between the copper plate and the ceramic substrate using an EPMA;
based on the backscattered electron image, measuring the area of the Ag—Cu eutectic structure layer continuously formed on the bonding interface in a measurement visual field at a magnification of 2000 times;
dividing the area of the Ag—Cu eutectic structure layer by the width of the measurement visual field, and
obtaining the average of the thicknesses in five measurement visual fields as the thickness of the Ag—Cu eutectic structure layer.

2. The power module substrate according to claim 1 , wherein
the ceramic substrate is formed of AlN, and
the thickness of the Ag—Cu eutectic structure layer is 14 μm or less.

3. The power module substrate according to claim 1 , wherein the ceramic substrate is formed of Si 3 N 4 , and
the thickness of the Ag—Cu eutectic structure layer is 1 μm or less.

4. A power module substrate according to claim 1 , wherein the power module substrate has no crack after repeating cooling-heating cycles of −45° C. to 125° C. for 3500 times on the power module substrate.

5. A power module substrate with a heat sink, comprising:
the power module substrate according to claim 1 ; and
a heat sink that cools the power module substrate.

6. A power module, comprising:
the power module substrate according to claim 1 ; and
an electronic component that is mounted on the power module substrate.

7. A power module substrate, comprising:
a ceramic substrate that is formed of AlN or Si3N4 and has a first surface;
a copper plate that is formed of copper or a copper alloy and is laminated and bonded on the first surface of the ceramic substrate;
a nitride layer that contains a nitride of Nb and is formed on the first surface of the ceramic substrate between the copper plate and the ceramic substrate; and
an Ag—Cu eutectic structure layer that has a thickness of 15 μm or less and is formed between the nitride layer and the copper plate,
wherein
the thickness of the Ag—Cu eutectic structure layer is measured by a method comprising:
obtaining a backscattered electron image of an interface between the copper plate and the ceramic substrate using an EPMA;
based on the backscattered electron image, measuring the area of the Ag—Cu eutectic structure layer continuously formed on the bonding interface in a measurement visual field at a magnification of 2000 times;
dividing the area of the Ag—Cu eutectic structure layer by the width of the measurement visual field, and
obtaining the average of the thicknesses in five measurement visual fields as the thickness of the Ag—Cu eutectic structure layer.

Assignees

• Mitsubishi Materials Corp

Inventors

• Terasaki Nobuyuki
• Nagatomo Yoshiyuki
• Nishikawa Kimihito
• Kuromitsu Yoshirou

Classifications

• H10W90/734

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W40/255

  having a laminate or multilayered structure, e.g. direct bond copper [DBC] ceramic substrates · CPC title

• C04B2237/122

  based on refractory metals · CPC title

• B23K35/025

  Pastes, creams or slurries · CPC title

• C04B2237/125

  based on noble metals, e.g. silver · CPC title