# US 10,485,112 B2 · Ceramic circuit substrate and method for producing ceramic circuit substrate

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- Number: US 10,485,112 B2
- Document ID: US10485112B2
- Status: Granted
- Kind: B2
- Application number: 16/097,383
- Filed: 2017-06-08
- Published: 2019-05-16
- Granted: 2019-11-19
- Earliest claimed: 2016-06-10
- Assignees: Tanaka Kikinzoku Kogyo K.K.
- Applicants: Tanaka Kikinzoku Kogyo K.K.
- Inventors: Takaomi Kishimoto
- Web page: https://patentgrep.com/patent/US10485112B2

## CPC

- H05K 3/4644: {by building the multilayer layer by layer, i.e. build-up multilayer circuits (making via holes in the insulating layers H05K3/0011; special circuit boards as base or core whereon the multilayer is built H05K3/4602)}
- B23K 1/0016: {Soldering of electronic components}
- B23K 35/007: {at least one of the workpieces being of copper or another noble metal}
- B23K 35/0238: {layered}
- B23K 35/3006: {Ag as the principal constituent}
- B32B 15/018: {one layer being formed of a noble metal or a noble metal alloy}
- C04B 37/023: {characterised by the interlayer used (C04B37/028 takes precedence)}
- C04B 37/026: {consisting of metals or metal salts}
- C22C 5/06: Alloys based on silver
- C22C 5/08: with copper as the next major constituent
- C22C 9/00: Alloys based on copper
- H05K 1/0203: {Cooling of mounted components (H05K1/0272 takes precedence)}
- H05K 1/0271: {Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion}
- H05K 1/0306: {Inorganic insulating substrates, e.g. ceramic, glass}
- H05K 1/09: Use of materials for the {conductive, e.g. } metallic pattern
- H10W 40/10: Arrangements for heating
- H10W 70/60: Insulating or insulated package substrates; Interposers; Redistribution layers (leadframes H10W70/40)
- H10W 70/692: Ceramics or glasses
- B23K 35/26: with the principal constituent melting at less than 400°C
- B23K 35/286: {Al as the principal constituent}
- B23K 35/30: with the principal constituent melting at less than 1550°C
- B23K 35/32: with the principal constituent melting at more than 1550°C
- B23K 35/325: {Ti as the principal constituent}
- B23K 2101/42: Printed circuits
- B23K 2103/12: Copper or alloys thereof
- C04B 2237/125: based on noble metals, e.g. silver
- C04B 2237/126: wherein the active component for bonding is not the largest fraction of the interlayer
- C04B 2237/127: The active component for bonding being a refractory metal
- C04B 2237/343: Alumina or aluminates
- C04B 2237/348: Zirconia, hafnia, zirconates or hafnates
- C04B 2237/36: Non-oxidic
- C04B 2237/361: Boron nitride
- C04B 2237/363: Carbon
- C04B 2237/365: Silicon carbide
- C04B 2237/366: Aluminium nitride
- C04B 2237/368: Silicon nitride
- C04B 2237/407: Copper
- C04B 2237/50: Processing aspects relating to ceramic laminates or to the joining of ceramic articles with other articles by heating
- C04B 2237/52: Pre-treatment of the joining surfaces, e.g. cleaning, machining
- C04B 2237/60: Forming at the joining interface or in the joining layer specific reaction phases or zones, e.g. diffusion of reactive species from the interlayer to the substrate or from a substrate to the joining interface, carbide forming at the joining interface
- C04B 2237/708: of one or more of the interlayers
- C04B 2237/74: Forming laminates or joined articles comprising at least two different interlayers separated by a substrate
- H05K 3/0061: {onto a metallic substrate, e.g. a heat sink (heat sinks for electric apparatus H05K7/20)}
- H05K 3/388: {by the use of a metallic or inorganic thin film adhesion layer}
- H05K 2201/066: Heatsink mounted on the surface of the printed circuit board [PCB]
- H05K 2203/128: Molten metals, e.g. casting thereof, or melting by heating and excluding molten solder
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- 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
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A ceramic circuit substrate according to the present invention includes a ceramic substrate, a copper circuit made of a copper-based material bonded, via a bonding layer, to a surface of the ceramic, and a copper heat sink made of the copper-based material bonded, via a bonding layer, to the other surface of the ceramic. The bonding layers each include a brazing material component including two or more kinds of metals, such as Ag, and an active metal having a predetermined concentration. The bonding layers each include a brazing material layer including the brazing material component, and an active metal compound layer containing the active metal. A ratio of a bonding area of the active metal compound layer in a bonding area of each of the bonding layers is 88% or more.

## Claims

### Claim 1

A ceramic circuit substrate comprising:
a ceramic substrate;
a copper circuit made of a copper-based material bonded, via a first bonding layer, to a surface of the ceramic substrate; and
a copper heat sink made of the copper-based material bonded, via a second bonding layer, to the other surface of the ceramic substrate,
wherein the bonding layers each include a brazing material component comprising at least two or more kinds of metals together with Ag and Cu serving as essential components, at least one active metal, the active metal, in the bonding layers, having a content ranging, relative to a metallic element content in each of the whole bonding layers, from 0.5 mass % to 2.0 mass % inclusive, and the Cu, in each of the bonding layers, having a content ranging from 20 mass % to 40 mass % inclusive,
wherein the bonding layers each have a two-layer structure of:
a brazing material layer comprising the brazing material component but not the active metal, and
an active metal compound layer containing the active metal, the active metal compound layer being formed along a bonded interface between the ceramic substrate and the bonding layer, and
wherein, further, a ratio of a bonding area between the active metal compound layer and the ceramic substrate in a bonding area between each of the bonding layers and the ceramic substrate is 88% or more.

### Claim 2 (depends on 1)

The ceramic circuit substrate according to claim 1, wherein at least one of Sn, In, Ni, Si, and Li is contained as the brazing material component.

### Claim 3 (depends on 1)

The ceramic circuit substrate according to claim 1, wherein at least one of Ti, Zr, Hf, Nb, Ta, V, Cr, Y, Al, and Mo is contained as one of the active metals.

### Claim 4 (depends on 1)

The ceramic circuit substrate according to claim 1, wherein a thickness of the active metal compound layer ranges, relative to each of the whole bonding layers, from 1/40 to 1/10 inclusive.

### Claim 5 (depends on 1)

The ceramic circuit substrate according to claim 1, wherein a thickness of each of the bonding layers ranges from 5 μm to 50 μm inclusive.

### Claim 6 (depends on 1)

The ceramic circuit substrate according to claim 1, wherein each of the bonding layers includes at least one of an Ag—Cu—Ti alloy, an Ag—Cu—Ti—Sn alloy, an Ag—Cu—Ti—Zr—Sn alloy, an Ag—Cu alloy, an Ag—Cu—Sn alloy, and an Ag—Cu—Zr alloy.

### Claim 7 (depends on 1)

The ceramic circuit substrate according to claim 1, wherein the ceramic substrate is made of one of aluminum nitride, silicon nitride, alumina, zirconia, lanthanum boride, boron nitride, silicon carbide, and graphite.

### Claim 8 (depends on 1)

A method for producing the ceramic circuit substrate according to claim 1, the method comprising:
preparing a clad composite material containing, on a surface of a copper plate material comprising a copper-based material, an active metal brazing material in a bulk form having a brazing material component and an active metal alloyed;
arranging the composite material on both of surfaces of a ceramic substrate to allow the active metal brazing material to abut the surfaces; and
heating the composite material to melt the active metal brazing material to bond the copper plate material onto both of the surfaces of the ceramic substrate.

### Claim 9 (depends on 8)

The method for producing the ceramic circuit substrate, according to claim 8, wherein the active metal brazing material comprises an Ag—Cu—Ti alloy, an Ag—Cu—Ti—Sn alloy, or an Ag—Cu—Ti—Zr—Sn alloy.

### Claim 10 (depends on 8)

The method for producing the ceramic circuit substrate, according to claim 8, wherein a planar shape of the composite material to be bonded onto one of the surfaces of the ceramic substrate is machined into a circuit shape.

### Claim 11 (depends on 2)

The ceramic circuit substrate according to claim 2, wherein at least one of Ti, Zr, Hf, Nb, Ta, V, Cr, Y, Al, and Mo is contained as one of the active metals.

### Claim 12 (depends on 2)

The ceramic circuit substrate according to claim 2, wherein a thickness of the active metal compound layer ranges, relative to each of the whole bonding layers, from 1/40 to 1/10 inclusive.

### Claim 13 (depends on 3)

The ceramic circuit substrate according to claim 3, wherein a thickness of the active metal compound layer ranges, relative to each of the whole bonding layers, from 1/40 to 1/10 inclusive.

### Claim 14 (depends on 2)

The ceramic circuit substrate according to claim 2, wherein a thickness of each of the bonding layers ranges from 5 μm to 50 μm inclusive.

### Claim 15 (depends on 3)

The ceramic circuit substrate according to claim 3, wherein a thickness of each of the bonding layers ranges from 5 μm to 50 μm inclusive.

### Claim 16 (depends on 2)

The ceramic circuit substrate according to claim 2, wherein each of the bonding layers includes at least one of an Ag—Cu—Ti alloy, an Ag—Cu—Ti—Sn alloy, an Ag—Cu—Ti—Zr—Sn alloy, an Ag—Cu alloy, an Ag—Cu—Sn alloy, and an Ag—Cu—Zr alloy.

### Claim 17 (depends on 3)

The ceramic circuit substrate according to claim 3, wherein each of the bonding layers includes at least one of an Ag—Cu—Ti alloy, an Ag—Cu—Ti—Sn alloy, an Ag—Cu—Ti—Zr—Sn alloy, an Ag—Cu alloy, an Ag—Cu—Sn alloy, and an Ag—Cu—Zr alloy.

### Claim 18 (depends on 2)

The ceramic circuit substrate according to claim 2, wherein the ceramic substrate is made of one of aluminum nitride, silicon nitride, alumina, zirconia, lanthanum boride, boron nitride, silicon carbide, and graphite.

### Claim 19 (depends on 2)

A method for producing the ceramic circuit substrate according to claim 2, the method comprising:
preparing a clad composite material containing, on a surface of a copper plate material comprising a copper-based material, an active metal brazing material in a bulk form having a brazing material component and an active metal alloyed;
arranging the composite material on both of surfaces of a ceramic substrate to allow the active metal brazing material to abut the surfaces; and
heating the composite material to melt the active metal brazing material to bond the copper plate material onto both of the surfaces of the ceramic substrate.

### Claim 20 (depends on 9)

The method for producing the ceramic circuit substrate, according to claim 9, wherein a planar shape of the composite material to be bonded onto one of the surfaces of the ceramic substrate is machined into a circuit shape.