# US 8,785,785 B2 · Ceramic circuit board and process for producing same

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- Number: US 8,785,785 B2
- Document ID: US8785785B2
- Status: Granted
- Kind: B2
- Application number: 13/418,813
- Filed: 2012-03-13
- Published: 2012-07-05
- Granted: 2014-07-22
- Earliest claimed: 2009-09-15
- Assignees: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Applicants: Hiromasa Kato
- Inventors: Hiromasa Kato
- Web page: https://patentgrep.com/patent/US8785785B2

## CPC

- H05K 3/062: {consisting of metals or alloys or metallic inorganic compounds (H05K3/065 takes precedence)}
- B23K 1/0016: {Soldering of electronic components}
- C04B 37/026: {consisting of metals or metal salts}
- H05K 3/06: the conductive material being removed chemically or electrolytically, e.g. by photo-etch process {(semi-additive methods H05K3/108)}
- H05K 3/38: Improvement of the adhesion between the insulating substrate and the metal
- H10D 64/011: {of electrodes ohmically coupled to a semiconductor}
- H10W 40/255: {having a laminate or multilayered structure, e.g. direct bond copper [DBC] ceramic substrates}
- H10W 70/692: Ceramics or glasses
- B23K 2101/36: Electric or electronic devices
- C04B 2235/658: Atmosphere during thermal treatment
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B 2235/9607: Thermal properties, e.g. thermal expansion coefficient
- 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 2237/366: Aluminium nitride
- C04B 2237/368: Silicon nitride
- C04B 2237/706: of one or more of the metallic layers or articles
- 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
- H05K 1/0306: {Inorganic insulating substrates, e.g. ceramic, glass}
- H05K 3/067: {Etchants}
- H05K 3/202: {using self-supporting metal foil pattern}
- H05K 3/3485: Application of solder paste, slurry or powder (using printing techniques to form the desired conductive pattern of the printed circuit by applying conductive material H05K3/12)
- H05K 2201/0355: Metal foils
- H05K 2203/013: Inkjet printing, e.g. for printing insulating material or resist
- H05K 2203/0392: Pretreatment of metal, e.g. before finish plating, etching
- H05K 2203/0465: Shape of solder, e.g. differing from spherical shape, different shapes due to different solder pads
- H05K 2203/0545: Pattern for applying drops or paste; Applying a pattern made of drops or paste
- H05K 2203/125: Inorganic compounds, e.g. silver salt
- H05K 2203/167: Using mechanical means for positioning, alignment or registration, e.g. using rod-in-hole alignment
- Y10T 29/49156: with selective destruction of conductive paths
- 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
- 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
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

According to one embodiment, a ceramic circuit board includes a ceramic substrate, a copper circuit plate and a brazing material protrudent part. The copper circuit plate is bonded to at least one surface of the ceramic substrate through a brazing material layer including Ag, Cu, and Ti. The brazing material protrudent part includes a Ti phase and a TiN phase by 3% by mass or more in total, which is different from the total amount of a Ti phase and a TiN phase in the brazing material layer that is interposed between the ceramic substrate and the copper circuit plate. The number of voids each having an area of 200 μm2 or less in the brazing material protrudent part is one or less (including zero).

## Claims

### Claim 1

A ceramic circuit board, comprising:
a ceramic substrate;
a copper circuit plate bonded to at least one surface of the ceramic substrate through a brazing material layer comprising Ag, Cu, and Ti; and
a brazing material protrudent part formed by the brazing material layer which protrudes outside from a side surface of the copper circuit plate;
wherein the brazing material protrudent part comprises a Ti phase and a TiN phase of 3% by mass or more in total, which is different from the total amount of a Ti phase and a TiN phase in the brazing material layer that is interposed between the ceramic substrate and the copper circuit plate, and a number of voids each having an area of 200 μm2 or less in the brazing material protrudent part is one or less (including zero).

### Claim 2 (depends on 1)

The ceramic circuit board according to claim 1, wherein the brazing material protrudent part comprises the Ti phase and TiN phase of from 3% by mass to 40% by mass in total.

### Claim 3 (depends on 1)

The ceramic circuit board according to claim 1, wherein the brazing material protrudent part has a protrudent length that is 0.01 mm or more.

### Claim 4 (depends on 1)

The ceramic circuit board according to claim 1, wherein the ceramic substrate is composed of silicon nitride, aluminum nitride, or alumina, and the copper circuit plate has a thickness of 0.25 mm or more.

### Claim 5 (depends on 1)

The ceramic circuit board according to claim 1, wherein the brazing material layer is formed using a brazing material having a composition consisting of Ag: 90 to 50% by weight, Sn and/or In: 5 to 15% by weight, Ti: 0.1 to 6% by weight, and a remnant Cu and unavoidable impurities.

### Claim 6

A ceramic circuit board, comprising:
a ceramic substrate;
a copper circuit plate;
a brazing material layer including Ag, Cu, and Ti disposed between the ceramic substrate and the copper circuit plate to bond the copper circuit plate to the ceramic substrate; and
a brazing material protrudent part formed by the brazing material layer that protrudes out from between the ceramic substrate and the copper circuit plate, and from outside of a side surface of the copper circuit plate;
wherein the brazing material protrudent part has a Ti phase and a TiN phase of 3% by mass or more in total, which is different from a total amount of a Ti phase and a TiN phase in the brazing material layer interposed between the ceramic substrate and the copper circuit plate;
wherein the brazing material protrudent part includes no more than one void having an area of 200 μm2 or less; and
wherein the ceramic circuit board has both a high thermal cycle resistance and a high thermal shock resistance.

### Claim 7 (depends on 6)

The ceramic circuit board of claim 6, wherein the brazing material protrudent part is subject to only a single etchant.

### Claim 8 (depends on 7)

The ceramic circuit board of claim 7, wherein the brazing material protrudent part is etched with a copper plate etchant.

### Claim 9 (depends on 6)

The ceramic circuit board of claim 6, wherein the brazing material protrudent part is etched with a copper plate etchant.

### Claim 10 (depends on 6)

The ceramic circuit board of claim 6, wherein the brazing material protrudent part is etched with a copper plate etchant including ferric chloride or cupric chloride.

### Claim 11 (depends on 6)

The ceramic circuit board of claim 6, wherein the brazing material protrudent part is etched with a copper plate etchant including ferric chloride or cupric chloride of no greater than 15 wt %.

### Claim 12 (depends on 6)

The ceramic circuit board of claim 6, wherein the brazing material is not subject to a brazing material etchant.

### Claim 13 (depends on 6)

The ceramic circuit board of claim 6, wherein the brazing material protrudent part is without voids having an area of greater than 200 μm2.

### Claim 14 (depends on 6)

The ceramic circuit board of claim 6, wherein the brazing material protrudent part includes a plurality of pores etched therein with a copper plate etchant.

### Claim 15

A ceramic circuit board, comprising:
a ceramic substrate;
a copper circuit plate;
a brazing material layer including Ag, Cu, and Ti disposed between the ceramic substrate and the copper circuit plate to bond the copper circuit plate to the ceramic substrate; and
a brazing material protrudent part of the brazing material layer that protrudes out from between the ceramic substrate and the copper circuit plate, and from outside of a side surface of the copper circuit plate;
wherein the brazing material protrudent part has a Ti phase and a TiN phase of 3% by mass or more in total, which is different from a total amount of a Ti phase and a TiN phase in the brazing material layer interposed between the ceramic substrate and the copper circuit plate;
wherein the brazing material protrudent part is etched with a copper plate etchant including 15 wt % of ferric chloride or cupric chloride such that the brazing material protrudent part includes no more than one void having an area of 200 μm2 or less and no voids having an area greater than 200 μm2; and
wherein the ceramic circuit board has both a high thermal cycle resistance and a high thermal shock resistance.

### Claim 16 (depends on 15)

The ceramic circuit board of claim 15, wherein the brazing material protrudent part is subject to only a single etchant.

### Claim 17 (depends on 15)

The ceramic circuit board of claim 15, wherein the brazing material is not subject to a brazing material etchant.

### Claim 18 (depends on 15)

The ceramic circuit board of claim 15, wherein the brazing material protrudent part includes a plurality of pores etched therein with the copper plate etchant.

### Claim 19 (depends on 15)

The ceramic circuit board of claim 15, wherein the brazing material protrudent part includes the Ti phase and the TiN phase from 3% by mass to 40% by mass in total.

### Claim 20 (depends on 15)

The ceramic circuit board of claim 15, wherein the brazing material protrudent part has a protrudent length that is 0.01 mm or more and is 30% or less of a space in the copper circuit plate.