# US 2019/0355690 A1 · Copper paste for pressureless bonding, bonded body and semiconductor device

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- Number: US 2019/0355690 A1
- Document ID: US20190355690A1
- Status: Published application
- Kind: A1
- Application number: 16/476,969
- Filed: 2017-01-11
- Published: 2019-11-21
- Earliest claimed: 2017-01-11
- Assignees: Hitachi Chemical Company, Ltd.
- Applicants: Hitachi Chemical Company, Ltd.
- Inventors: Hideo NAKAKO; Kazuhiko KURAFUCHI; Yoshinori EJIRI; Dai ISHIKAWA; Chie SUGAMA; Yuki KAWANA
- Web page: https://patentgrep.com/patent/US20190355690A1

## CPC

- B23K 35/025: {Pastes, creams or slurries}
- B22F 1/052: characterised by a mixture of particles of different sizes or by the particle size distribution
- B22F 1/10: Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
- B22F 7/064: {using an intermediate powder layer}
- C09D 1/00: Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
- C09D 5/24: Electrically-conducting paints {(conductive materials H01B1/00)}
- H01B 1/02: mainly consisting of metals or alloys
- H01B 1/22: the conductive material comprising metals or alloys
- H10W 72/01323: {in liquid form, e.g. by dispensing droplets or by screen printing}
- H10W 72/01333: {in liquid form, e.g. spin coating, spray coating or immersion coating}
- H10W 72/01335: {by plating, e.g. electroless plating or electroplating}
- H10W 72/01361: {Chemical or physical modification, e.g. by sintering or anodisation (patterning H10W72/01351)}
- H10W 72/01365: {Thermally treating (reflowing H10W72/01357)}
- H10W 72/01938: {in gaseous form, e.g. by CVD or PVD}
- H10W 72/073: {of die-attach connectors}
- H10W 72/07331: {Connecting techniques}
- H10W 72/07332: {Compression bonding, e.g. thermocompression bonding}
- H10W 72/07334: {Using a reflow oven}
- H10W 72/07335: {Applying EM radiation, e.g. induction heating or using a laser}
- H10W 72/07341: {Controlling the bonding environment, e.g. atmosphere composition or temperature}
- H10W 72/325: {Die-attach connectors having a filler embedded in a matrix}
- H10W 72/351: {Materials of die-attach connectors}
- H10W 72/352: {comprising metals or metalloids, e.g. solders}
- H10W 72/353: {not comprising solid metals or solid metalloids, e.g. ceramics}
- H10W 72/354: {comprising polymers}
- H10W 72/551: {Materials of bond wires}
- H10W 72/59: Bond pads specially adapted therefor
- H10W 72/884: {Die-attach connectors and bond wires}
- H10W 72/923: {Bond pads having multiple stacked layers}
- H10W 72/952: {comprising metals or metalloids, e.g. PbSn, Ag or Cu}
- H10W 90/736: {between a chip and a stacked lead frame, conducting package substrate or heat sink}
- H10W 90/756: {between a chip and a stacked lead frame, conducting package substrate or heat sink}
- 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
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A copper paste for pressureless bonding is a copper paste for pressureless bonding, containing: metal particles; and a dispersion medium, in which the metal particles include sub-micro copper particles having a volume average particle diameter of greater than or equal to 0.01 μm and less than or equal to 0.8 μm, and micro copper particles having a volume average particle diameter of greater than or equal to 2.0 μm and less than or equal to 50 μm, and the dispersion medium contains a solvent having a boiling point of higher than or equal to 300° C., and a content of the solvent having a boiling point of higher than or equal to 300° C. is greater than or equal to 2 mass % on the basis of a total mass of the copper paste for pressureless bonding.

## Claims

### Claim 1

A copper paste for pressureless bonding, containing:
metal particles; and
a dispersion medium,
wherein the metal particles include sub-micro copper particles having a volume average particle diameter of greater than or equal to 0.01 μm and less than or equal to 0.8 μm, and micro copper particles having a volume average particle diameter of greater than or equal to 2.0 μm and less than or equal to 50 μm, and
the dispersion medium contains a solvent having a boiling point of higher than or equal to 300° C., and a content of the solvent having a boiling point of higher than or equal to 300° C. is greater than or equal to 2 mass % on the basis of a total mass of the copper paste for pressureless bonding.

### Claim 2

A copper paste for pressureless bonding, containing:
metal particles; and
a dispersion medium,
wherein the metal particles include sub-micro copper particles having a volume average particle diameter of greater than or equal to 0.01 μm and less than or equal to 0.8 μm, and micro copper particles having a volume average particle diameter of greater than or equal to 2.0 μm and less than or equal to 50 μm, and
the dispersion medium contains a solvent having a boiling point of higher than or equal to 300° C., and a content of the solvent having a boiling point of higher than or equal to 300° C. is greater than or equal to 8 volume % on the basis of a total volume of the copper paste for pressureless bonding.

### Claim 3 (depends on 1)

The copper paste for pressureless bonding according to claim 1,
wherein the solvent having a boiling point of higher than or equal to 300° C. has at least one type of group selected from the group consisting of a hydroxy group, an ether group, and an ester group.

### Claim 4 (depends on 1)

The copper paste for pressureless bonding according to claim 1,
wherein when the copper paste for pressureless bonding that exists between two members is heated at a temperature of higher than or equal to 250° C. and lower than 350° C., the micro copper particles and the sub-micro copper particles are sintered, metal bonding is formed, and the two members are bonded together at a die shear strength of greater than or equal to 10 MPa and a thermal conductivity of greater than or equal to 100 W/(m·K).

### Claim 5 (depends on 1)

The copper paste for pressureless bonding according to claim 1,
wherein the content of the solvent having a boiling point of higher than or equal to 300° C. that remains when a temperature rises to 300° C. from 25° C. is greater than or equal to 1 mass % on the basis of a mass of the copper paste for pressureless bonding when a temperature rises to 300° C.

### Claim 6 (depends on 1)

A bonded body, comprising:
a first member;
a second member having a thermal expansion rate different from that of the first member; and
a sintered body of the copper paste for pressureless bonding according to claim 1, the sintered body bonding the first member and the second member together.

### Claim 7 (depends on 1)

A manufacturing method of a bonded body, comprising:
a step of preparing a laminated body in which a first member, the copper paste for pressureless bonding according to claim 1, and a second member having a thermal expansion rate different from that of the first member are laminated in this order in a direction side in which self-weight of the first member acts, and of sintering the copper paste for pressureless bonding in a state of receiving the self-weight of the first member, or the self-weight of the first member and a pressure of less than or equal to 0.01 MPa.

### Claim 8 (depends on 1)

A semiconductor device, comprising:
a first member;
a second member having a thermal expansion rate different from that of the first member; and
a sintered body of the copper paste for pressureless bonding according to claim 1, the sintered body bonding the first member and the second member together,
wherein at least one of the first member and the second member is a semiconductor element.

### Claim 9 (depends on 2)

The copper paste for pressureless bonding according to claim 2,
wherein the solvent having a boiling point of higher than or equal to 300° C. has at least one type of group selected from the group consisting of a hydroxy group, an ether group, and an ester group.

### Claim 10 (depends on 2)

The copper paste for pressureless bonding according to claim 2,
wherein when the copper paste for pressureless bonding that exists between two members is heated at a temperature of higher than or equal to 250° C. and lower than 350° C., the micro copper particles and the sub-micro copper particles are sintered, metal bonding is formed, and the two members are bonded together at a die shear strength of greater than or equal to 10 MPa and a thermal conductivity of greater than or equal to 100 W/(m·K).

### Claim 11 (depends on 2)

The copper paste for pressureless bonding according to claim 2,
wherein the content of the solvent having a boiling point of higher than or equal to 300° C. that remains when a temperature rises to 300° C. from 25° C. is greater than or equal to 1 mass % on the basis of a mass of the copper paste for pressureless bonding when a temperature rises to 300° C.