# US 10,872,841 B2 · Ceramic metal circuit board and semiconductor device using the same

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- Number: US 10,872,841 B2
- Document ID: US10872841B2
- Status: Granted
- Kind: B2
- Application number: 15/742,829
- Filed: 2016-06-01
- Published: 2018-07-05
- Granted: 2020-12-22
- Earliest claimed: 2015-07-09
- Assignees: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Applicants: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Inventors: Takayuki Naba; Hiromasa Kato; Noboru Kitamori
- Web page: https://patentgrep.com/patent/US10872841B2

## CPC

- H10W 40/255: {having a laminate or multilayered structure, e.g. direct bond copper [DBC] ceramic substrates}
- C04B 37/026: {consisting of metals or metal salts}
- H10W 70/20: Conductive package substrates serving as an interconnection, e.g. metal plates (leadframes H10W70/40)
- H10W 70/65: Shapes or dispositions of interconnections
- H10W 70/66: Conductive materials thereof
- H10W 90/00: Package configurations
- H10W 90/701: {characterised by the relative positions of pads or connectors relative to package parts}
- C04B 2237/121: based on aluminium
- C04B 2237/124: based on copper
- C04B 2237/125: based on noble metals, e.g. silver
- C04B 2237/343: Alumina or aluminates
- C04B 2237/366: Aluminium nitride
- C04B 2237/368: Silicon nitride
- C04B 2237/402: Aluminium
- C04B 2237/407: Copper
- C04B 2237/704: of one or more of the ceramic layers or articles
- C04B 2237/706: of one or more of the metallic layers or articles
- C04B 2237/708: of one or more of the interlayers
- C04B 2237/72: Forming laminates or joined articles comprising at least two interlayers directly next to each other
- C04B 2237/86: Joining of two substrates at their largest surfaces, one surface being complete joined and covered, the other surface not, e.g. a small plate joined at it's largest surface on top of a larger plate
- C04B 2237/88: Joining of two substrates, where a substantial part of the joining material is present outside of the joint, leading to an outside joining of the joint
- H10W 40/037: {Assembling together parts thereof}
- H10W 40/22: characterised by their shape, e.g. having conical or cylindrical projections
- H10W 70/692: Ceramics or glasses
- H10W 72/352: {comprising metals or metalloids, e.g. solders}
- H10W 72/884: {Die-attach connectors and bond wires}
- H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10W 90/736: {between a chip and a stacked lead frame, conducting package substrate or heat sink}
- H10W 90/754: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

The present invention provides a ceramic metal circuit board including a ceramic substrate and metal plates bonded to both surfaces of the ceramic substrate through respective bonding layers, wherein a metal film is provided on a surface of one metal plate bonded to one surface of the ceramic substrate; and at least a part of another metal plate bonded to another surface of the ceramic substrate is not provided with the metal film. Preferably, a protruding portion is formed as a portion of the bonding layer so as to protrude from a side surface of each of the metal plates. According to the above-described configuration, it is possible to provide a ceramic circuit board which is easy to use according to the parts to be bonded and is excellent in heat-cycle resistance characteristics.

## Claims

### Claim 1

A ceramic metal circuit board comprising:
a ceramic substrate; and
first and second metal plates bonded to first and second opposite surfaces, respectively, of the ceramic substrate through respective bonding layers, the first and second metal plates each being made of a material selected from the group consisting of copper and a copper alloy;
a metal film on a surface of the first metal plate that is opposite the ceramic substrate; and
at least a part of a surface of the second metal plate that is opposite the ceramic substrate is not provided with the metal film; and
a semiconductor element or a metal terminal mounted to the at least a part of the surface of the second metal plate that is provided with no metal film with lead-free solder, wherein:
the maximum height surface roughness Rz of the surface of the first metal plate, the second metal plate, or both, that is provided with the metal film is 1.5 μm or less,
a thickness of the metal film is 10 μm or less on average,
average crystal grain sizes of the first metal plate and the second metal plate each is 200 μm or more, and
one of the metal plates on which the metal film is provided includes a recrystallized structure.

### Claim 2 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein a protruding portion is formed as a portion of each of the bonding layers in such a manner that the each of bonding layers protrudes from a side surface of each of the metal plates.

### Claim 3 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the bonding layers contain at least one element selected from Ag, Cu, and Al.

### Claim 4 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the metal film is formed in such a manner that the metal film covers respective side surfaces of the metal plates and the protruding portion.

### Claim 5 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the metal film is one selected from nickel, gold, or an alloy containing the nickel and the gold as main components.

### Claim 6 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the ceramic substrate is one selected from a silicon nitride substrate, an aluminum nitride substrate, and an aluminum oxide substrate.

### Claim 7 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein a metal terminal is bonded to such a position on a surface of one metal plate where the metal film is not provided.

### Claim 8 (depends on 1)

A semiconductor device which is configured by mounting a semiconductor element on the ceramic metal circuit board according to claim 1.

### Claim 9 (depends on 8)

The semiconductor device according to claim 8, wherein the semiconductor element is mounted through a solder layer on a position of a surface of a metal plate where the metal film is not provided.

### Claim 10 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the bonding layers contain at least one selected from Ag, Cu, and A1; and one of the metal plates on which the metal film is provided includes a recrystallized structure.

### Claim 11 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the metal plate is a copper plate.

### Claim 12 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the metal plate has a thickness of 0.20 mm or more.

### Claim 13 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the thickness of the metal film is 5 μm or less on average.

### Claim 14 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the ceramic substrate is one selected from a silicon nitride substrate, the bonding layers contain at least one element selected from Ag, Cu, and Al, and the metal plate is a copper plate.

### Claim 15 (depends on 1)

The ceramic metal circuit board according to claim 1, wherein the ceramic substrate is one selected from a silicon nitride substrate, the bonding layers contain at least one element selected from Ag, Cu, and Al, the metal plate is a copper plate, and the metal plate has a thickness of 0.20 mm or more.

### Claim 16 (depends on 8)

The semiconductor device according to claim 8, wherein the ceramic substrate is one selected from a silicon nitride substrate, the bonding layers contain at least one element selected from Ag, Cu, and Al, the metal plate is a copper plate, and the metal plate has a thickness of 0.20 mm or more.