# US 2014/0150929 A1 · Composition of solid-containing paste

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- Number: US 2014/0150929 A1
- Document ID: US20140150929A1
- Status: Published application
- Kind: A1
- Application number: 14/110,427
- Filed: 2012-04-04
- Published: 2014-06-05
- Earliest claimed: 2011-04-08
- Assignees: Micronic Mydata AB
- Inventors: Torbjorn Sandstrom
- Web page: https://patentgrep.com/patent/US20140150929A1

## CPC

- B23K 35/025: {Pastes, creams or slurries}
- B23K 35/3611: {Phosphates}
- B23K 35/3612: {with organic compounds as principal constituents}
- B23K 35/362: Selection of compositions of fluxes (B23K35/365, B23K35/368 take precedence)
- 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

## Abstract

Solder paste compositions and methods for applying solder paste. The solder paste includes lubricating additives to the flux to decrease friction and the changes of metal to metal contact between the surfaces of the solder balls and other surfaces that the solder balls come into contact with. The solder paste also includes solder balls of different average sizes, that improves the desirable liquid like properties of the granular paste while further reducing viscosity. As such, the solder paste is used in current screen printing solder paste application methods without the risk of clogging or agglomeration of solder paste particles on surfaces. The solder paste is also used in jetting or dispensing solder paste application methods without the risk of clogging or agglomeration within the cylinders/containers or apertures and nozzles that are used within such methods.

## Claims

### Claim 1

A solder paste, the solder paste having a first fraction f of solder balls with an average diameter s and a second fraction F with an average diameter S, the first fraction f and second fraction F taken by weight, where 3.5s<S and F<3f.

### Claim 2 (depends on 1)

The solder paste of claim 1, wherein a volume percent of solder balls of average diameter s ranges from 5-40% of an entire volume of solid phase material within the solder paste.

### Claim 3 (depends on 2)

The solder paste of claim 2, wherein the average diameter s of the first fraction f of solder balls ranges from 2-5 microns while the average diameter S of the second fraction F of solder balls is 20 microns.

### Claim 4 (depends on 1)

The solder paste of claim 1, wherein a solder paste bulk has a solid volume fraction between 40-50%.

### Claim 5 (depends on 1)

The solder paste of claim 1, wherein the solder paste is a polydispersion having a third fraction of solder balls, the third fraction of solder balls having an average diameter that is at least 3.5 times smaller than the average diameter s of the first fraction f of solder balls.

### Claim 6

A method of depositing solder paste onto a surface comprising:
introducing a volume of solder paste within a container, the container having an aperture, the solder paste having a first fraction f of solder balls with an average diameter s and a second fraction F with an average diameter S, the first fraction f and the second fraction F taken by weight, where 3.5s<S and F<3f; and
applying a force to the volume of solder paste such that a portion of the volume of solder paste is pushed out of the container through the aperture and is deposited onto a surface.

### Claim 7 (depends on 6)

The method of claim 6, wherein a volume percent of the solder balls of average diameter s within the solder paste ranges from 5-40% of an entire volume of solid phase material within the solder paste.

### Claim 8 (depends on 7)

The method of claim 7, wherein the average diameter s of the first fraction f of solder balls ranges from 2-5 microns while average diameter S of the second fraction F of solder balls is 20 microns.

### Claim 9 (depends on 6)

The method of claim 6, wherein a solder paste bulk has a solid volume fraction between 40-50%.

### Claim 10 (depends on 6)

The method of claim 6, wherein the solder paste is a polydispersion having a third fraction of solder balls, the third fraction of solder balls having an average diameter that is at least 3.5 times smaller than the average diameter s of the first fraction f of solder balls.

### Claim 11

A solder paste comprising:
solder balls; and
a flux medium, the flux medium including a volume of a lubricating agent, the lubricating agent reducing friction and instances of metal to metal contact between the solder balls and surfaces that the solder balls contact, the lubricating agent making up 0.05%-5% of a total volume of the flux medium.

### Claim 12 (depends on 11)

The solder paste of claim 11, wherein the lubricating agent contains molecules with a soap-like structure that includes a polar group, such polar group having an affinity for a surface of the solder balls within the solder paste.

### Claim 13 (depends on 12)

The solder paste of claim 12, wherein the molecules with a soap-like structure have a binding energy between 8 kcal/mol and 20 kcal/mol.

### Claim 14 (depends on 11)

The solder paste of claim 11, wherein the lubricating agent contains a phosphate ester component, such phosphate ester component making up 0.05%-2% of the volume of the flux medium.

### Claim 15 (depends on 11)

The solder paste of claim 11, wherein the lubricating agent contains a glycerol ester component.

### Claim 16 (depends on 11)

The solder paste of claim 11, wherein the lubricating agent contains a lamellar structure material, such lamellar structure material making up 0.2%-5% of the volume of the flux medium.

### Claim 17 (depends on 16)

The solder paste of claim 16, wherein the lamellar structure material is hexagonal boron nitride.

### Claim 18 (depends on 17)

The solder paste of claim 17, wherein the hexagonal boron nitride is a nanodispersion with particles having a diameter less than 200 nm.

### Claim 19 (depends on 17)

The solder paste of claim 17, wherein the hexagonal boron nitride is a nanodispersion with particles having a diameter less than 100 nm.

### Claim 20 (depends on 11)

The solder paste of claim 11, wherein the lubricating agent contains a fluorinated hydrocarbon component, such fluorinated hydrocarbon component making up 0.2%-5% of the volume of the flux medium.

### Claim 21 (depends on 11)

The solder paste of claim 11, wherein the lubricating agent is a metal hydrocarbyl dithiophosphate.

### Claim 22 (depends on 11)

The solder paste of claim 11, wherein the lubricating agent contains at least two of a group consisting of molecules with a soap-like structure, a phosphate ester component, a glycerol ester component, a lamellar structure material, a fluorinated hydrocarbon component, a metal hydrocarbyl dithiophosphate.

### Claim 23

A method of depositing solder paste onto a surface comprising:
introducing a volume of solder paste within a container, the container having an aperture, the solder paste including solder balls and a flux medium with a lubricating agent to reduce friction and instances of metal to metal contact between the solder balls and surfaces that the solder balls contact, the lubricating agent making up 0.05%-5% of a total volume of the flux medium; and
applying a force to the volume of solder paste such that a portion of the volume of solder paste is pushed out of the container through the aperture and is deposited onto a surface.

### Claim 24 (depends on 23)

The method of claim 23, wherein the lubricating agent contains molecules with a soap-like structure that includes a polar group, such polar group having an affinity for a surface of the solder balls within the solder paste.

### Claim 25 (depends on 24)

The method of claim 24, wherein the molecules with a soap-like structure have a binding energy between 8 kcal/mol and 20 kcal/mol.

### Claim 26 (depends on 23)

The method of claim 23, wherein the lubricating agent contains a phosphate ester component, such phosphate ester component making up 0.05%-2% of the volume of the flux medium.

### Claim 27 (depends on 23)

The method of claim 23, wherein the lubricating agent contains a glycerol ester component.

### Claim 28 (depends on 23)

The method of claim 23, wherein the lubricating agent contains a lamellar structure material, such lamellar structure material making up 0.2%-5% of the volume of the flux medium.

### Claim 29 (depends on 28)

The method of claim 28, wherein the lamellar structure material is hexagonal boron nitride.

### Claim 30 (depends on 29)

The method of claim 29, wherein the hexagonal boron nitride is a nanodispersion with particles having a diameter less than 200 nm.

### Claim 31 (depends on 29)

The method of claim 29, wherein the hexagonal boron nitride is a nanodispersion with particles having a diameter less than 100 nm.

### Claim 32 (depends on 23)

The method of claim 23, wherein the lubricating agent contains a fluorinated hydrocarbon component, such fluorinated hydrocarbon component making up 0.2%-5% of the volume of the flux medium.

### Claim 33 (depends on 23)

The method of claim 23, wherein the lubricating agent contains a metal hydrocarbyl dithiophosphate.

### Claim 34 (depends on 23)

The method of claim 23, wherein the lubricating agent contains at least two of a group consisting of molecules with a soap-like structure, a phosphate ester component, a glycerol ester component, a lamellar structure material, a fluorinated hydrocarbon component, a metal hydrocarbyl dithiophosphate.