# US 7,745,013 B2 · Solder foams, nano-porous solders, foamed-solder bumps in chip packages, methods of assembling same, and systems containing same

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- Number: US 7,745,013 B2
- Document ID: US7745013B2
- Status: Granted
- Kind: B2
- Application number: 11/323,218
- Filed: 2005-12-30
- Published: 2007-07-05
- Granted: 2010-06-29
- Earliest claimed: 2005-12-30
- Assignees: Intel Corporation
- Inventors: Heeman Choe; Daewoong Suh
- Web page: https://patentgrep.com/patent/US7745013B2

## CPC

- B23K 35/025: {Pastes, creams or slurries}
- B23K 35/22: characterised by the composition or nature of the material
- H05K 3/3436: {having an array of bottom contacts, e.g. pad grid array or ball grid array components}
- H05K 3/346: Solder materials or compositions specially adapted therefor
- H05K 2201/0116: Porous, e.g. foam
- H05K 2201/0308: Shape memory alloy [SMA]
- H10W 72/221: {Structures or relative sizes}
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- Y10S 428/929: Electrical contact feature
- Y10T 428/12181: Composite powder [e.g., coated, etc.]
- Y10T 428/12479: Porous [e.g., foamed, spongy, cracked, etc.]
- 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
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A foamed solder or a nano-porous solder is formed on a substrate of an integrated circuit package. The foamed solder exhibits a low modulus that resists cracking during shock and dynamic loading. The foamed solder is used as a solder bump for communication between an integrated circuit device and external structures.

## Claims

### Claim 1

An article comprising:
a foamed solder core of a first material;
a substrate upon which the foamed solder core is disposed,
an intermediate solder layer disposed upon the substrate and in contact with the foamed solder core, wherein the intermediate solder layer includes an average grain-size diameter of about 20 micrometers; and
a bond pad as part of the substrate, wherein the bond pad is in contact with the intermediate solder layer, and wherein the bond pad includes a grain morphology characteristic of elongated columnar.

### Claim 2 (depends on 1)

The article of claim 1, further including a solder shell of a second material covering the foamed solder core.

### Claim 3 (depends on 1)

The article of claim 1, wherein the foamed solder core is a material selected from cellular-foamed and reticulated-foamed.

### Claim 4 (depends on 1)

The article of claim 1, wherein the foamed solder core is a metal selected from copper-based solder, nickel-based solder, tin-based solder, indium-based solder, lead-based solder, and combinations thereof.

### Claim 5 (depends on 1)

The article of claim 1, wherein the foamed solder includes a shape-memory alloy.

### Claim 6 (depends on 1)

The article of claim 1, wherein the solder shell of a second material includes an intermetallic derivative of the foamed solder core.

### Claim 7 (depends on 1)

The article of claim 1,
wherein the intermediate solder layer is denser than the foamed solder core.

### Claim 8 (depends on 1)

The article of claim 1, wherein the foamed solder core is an elongate pad disposed upon the substrate; and
a bond pad as part of the substrate, wherein the bond pad is in contact with the elongate pad.

### Claim 9

An article comprising:
a foamed solder core of a first material;
a substrate upon which the foamed solder core is disposed, wherein the foamed solder core of a first material includes copper;
an intermediate solder layer disposed upon the substrate and in contact with the foamed solder core, wherein the intermediate solder layer includes copper; and
a bond pad as part of the substrate, wherein the bond pad is in contact with the intermediate solder layer, wherein the bond pad includes a grain morphology characteristic of elongated columnar, and wherein the bond pad includes copper.

### Claim 10 (depends on 9)

The article of claim 9, further including a solder shell of a second material covering the foamed solder core.

### Claim 11 (depends on 9)

The article of claim 9, wherein the foamed solder core is a material selected from cellular-foamed and reticulated-foamed.

### Claim 12 (depends on 9)

The article of claim 9, wherein the foamed solder core is a metal selected from copper-based solder, nickel-based solder, tin-based solder, indium-based solder, lead-based solder, and combinations thereof.

### Claim 13 (depends on 9)

The article of claim 9, wherein the foamed solder includes a shape-memory alloy.

### Claim 14 (depends on 9)

The article of claim 9, wherein the solder shell of a second material includes an intermetallic derivative of the foamed solder core.

### Claim 15 (depends on 9)

The article of claim 9, wherein the intermediate solder layer is denser than the foamed solder core.

### Claim 16 (depends on 9)

The article of claim 9, wherein the foamed solder core is an elongate pad disposed upon the substrate; and
a bond pad as part of the substrate, wherein the bond pad is in contact with the elongate pad.