# US RE45,537 E1 · Coated solder spheres and method for producing the same

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- Number: US RE45,537 E1
- Document ID: USRE45537E1
- Status: Granted
- Kind: E1
- Application number: 12/916,902
- Filed: 2010-11-01
- Granted: 2015-06-02
- Earliest claimed: 1999-04-09
- Assignees: Senju Metal Industry Co., Ltd.
- Applicants: Daisuke Sohma; Takahiro Roppongi
- Inventors: Daisuke Sohma; Takahiro Roppongi
- Web page: https://patentgrep.com/patent/USRE45537E1

## CPC

- B23K 35/365: Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials
- B05D 1/18: performed by dipping
- B23K 35/0244: {Powders, particles or spheres; Preforms made therefrom}
- B23K 2201/36
- H05K 3/3436: {having an array of bottom contacts, e.g. pad grid array or ball grid array components}
- H05K 2203/041: Solder preforms in the shape of solder balls
- H05K 2203/0195: Tool for a process not provided for in H05K3/00, e.g. tool for handling objects using suction, for deforming objects, for applying local pressure
- H05K 2203/0485: Tacky flux, e.g. for adhering components during mounting
- Y10T 428/2991: Coated
- B23K 35/3618: {Carboxylic acids or salts}
- B23K 35/3612: {with organic compounds as principal constituents}
- B23K 35/3615: {N-compounds}
- H05K 2203/127: Lubricants, e.g. during drilling of holes
- H05K 2203/122: Organic non-polymeric compounds, e.g. oil, wax or thiol
- 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
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Solder spheres which can avoid blackening during transportation have a substantially uniform coating of a lubricant on the surfaces thereof. They are produced by dipping freshly prepared solder spheres in a lubricant solution with a concentration of from 10 ppm to 1000 ppm followed by collection of the spheres and drying. The lubricant is preferably selected from an aliphatic hydrocarbon lubricant, a higher fatty alcohol or acid lubricant, a fatty acid amide lubricant, a metal soap lubricant, a fatty acid ester lubricant, a fluoroplastic lubricant, a silicone lubricant, and a combination thereof.

## Claims

### Claim 1

Solder spheres having a substantially uniform coating of a lubricant on the surfaces thereof.

### Claim 2 (depends on 1)

The solder spheres according to claim 1 wherein the lubricant is selected from the group consisting of an aliphatic hydrocarbon lubricant, a higher fatty alcohol or acid lubricant, a fatty acid amide lubricant, a metal soap lubricant, a fatty acid ester lubricant, a fluoroplastic lubricant, a silicone lubricant, and a combination thereof.

### Claim 3

A method for producing solder spheres coated with a lubricant, which comprises dipping solder spheres in a solution of a lubricant dissolved in an organic solvent with a concentration of from 10 ppm to 1000 ppm, removing the solder spheres from the solution, and volatilizing the solvent remaining on the solder spheres to form a substantially uniform lubricant coating on the surfaces of the solder spheres.

### Claim 4 (depends on 3)

The A method according to claim 3 for producing solder spheres coated with a lubricant, which comprises:
dipping solder spheres in a solution of a lubricant dissolved in an organic solvent with a concentration of from 10 ppm to 1000 ppm,
removing the solder spheres from the solution, and
volatilizing the solvent remaining on the solder spheres to form a substantially uniform coating consisting of a lubricant on the surfaces of the solder spheres, wherein the lubricant is selected from the group consisting of an aliphatic hydrocarbon lubricant, a higher fatty alcohol or acid lubricant, a fatty acid amide lubricant, a metal soap lubricant, a fatty acid ester lubricant, a fluoroplastic lubricant, a silicone lubricant, and a combination thereof.

### Claim 5 (depends on 3)

The method according to claim 3 wherein the solder spheres are freshly prepared solder spheres.

### Claim 6 (depends on 3)

The method according to claim 3 wherein the solder spheres are removed from the lubricant solution by centrifugation.

### Claim 7 (depends on 1)

A substrate for mounting an electronic component, said substrate having solder bumps formed from the solder spheres according to claim 1 on the surface thereof.

### Claim 8 (depends on 1)

A process for forming solder bumps on a substrate for mounting an electronic component, which comprises placing the solder spheres according to claim 1 on the surface of the substrate and heating the substrate to cause the solder spheres placed thereon to melt and form solder bumps bonded to the substrate.

### Claim 9 (depends on 8)

The process according to claim 8 wherein the substrate used for placement of the solder spheres has a surface coating of a soldering flux in those areas on which the solder spheres are to be placed.

### Claim 10

A solder sphere composition comprising lubricant coated solder spheres consisting of solder spheres each having the same diameter and a substantially uniform coating consisting of a lubricant on each of the surfaces of the solder spheres, wherein the lubricant is selected from the group consisting of an aliphatic hydrocarbon lubricant, a higher fatty alcohol lubricant, a higher fatty acid lubricant, a fatty acid amide lubricant, a metal soap lubricant, a fatty acid ester lubricant, a fluoroplastic lubricant, a silicone lubricant, and combinations thereof.

### Claim 11 (depends on 10)

The solder sphere composition according to claim 10 wherein the lubricant is stearamide.

### Claim 12 (depends on 10)

The solder sphere composition according to claim 10 wherein the diameter is 0.76 mm.

### Claim 13 (depends on 10)

The solder sphere composition according to claim 10 wherein the diameter is 0.15 mm.

### Claim 14 (depends on 10)

The solder sphere composition according to claim 10 wherein the diameter is 0.1 mm.

### Claim 15 (depends on 10)

The solder sphere composition according to claim 10 wherein the plurality of solder spheres are each sized and configured for use on a lead that is on a substrate of an electronic component.

### Claim 16

A solder sphere composition consisting of a plurality of lubricant coated solder spheres consisting of solder spheres and a substantially uniform coating consisting of a lubricant on the surface of each of the solder spheres, wherein each of the solder spheres has the same diameter and the diameter is sized for placement onto a substrate for use in a ball grid array package, wherein the lubricant is selected from the group consisting of an aliphatic hydrocarbon lubricant, a higher fatty alcohol lubricant, a higher fatty acid lubricant, a fatty acid amide lubricant, a metal soap lubricant, a fatty acid ester lubricant, a fluoroplastic lubricant, a silicone lubricant, and combinations thereof.

### Claim 17 (depends on 16)

The solder sphere composition according to claim 16 wherein the diameter is 0.76 mm.

### Claim 18 (depends on 16)

The solder sphere composition according to claim 16 wherein the diameter is 0.15 mm.

### Claim 19 (depends on 16)

The solder sphere composition according to claim 16 wherein the diameter is 0.1 mm.

### Claim 20 (depends on 16)

The solder sphere composition according to claim 16 wherein the lubricant is stearamide.

### Claim 21 (depends on 16)

The solder sphere composition according to claim 16 wherein said substantially uniform lubricant coating is produced by dipping the plurality of the solder spheres in a solution of the lubricant dissolved in an organic solvent with a concentration of from 10 ppm to 1000 ppm, removing the plurality of solder spheres from the solution, and volatilizing the solvent remaining on the plurality of solder spheres to form the substantially uniform lubricant coating on each of the surfaces of the plurality of solder spheres, wherein the lubricant coating is dry.

### Claim 22 (depends on 11)

A process for forming solder bumps on a BGA substrate for mounting an electronic component, which comprises placing the solder sphere composition according to claim 11 on a surface of the substrate by using a solder sphere mounter comprising a suction head having suction ports by which the plurality of solder spheres are held and released onto the BGA substrate and heating the substrate to cause the plurality of solder spheres placed thereon to melt and form solder bumps bonded to the substrate.

### Claim 23 (depends on 22)

The process according to claim 22 wherein the substrate used for placement of the plurality of solder spheres has a surface coating of a soldering flux in those areas on which the plurality of solder spheres are placed.