Self-heating solder flux material

Patent metadata

Field	Value
Publication number	US-10328535-B2
Application number	US-201615344850-A
Country	US
Kind code	B2
Filing date	Nov 7, 2016
Priority date	Nov 7, 2016
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A self-heating solder flux material includes a solder flux material and a multi-compartment microcapsule. The solder flux material includes a solvent carrier, and the multi-compartment microcapsule includes a first compartment, a second compartment, and an isolating structure. The first compartment contains a first reactant, and the second compartment contains a second reactant. The isolating structure separates the first compartment from the second compartment. The isolating structure is adapted to rupture in response to a stimulus. Rupture of the isolating structure results in an exothermic reaction between the first reactant and the second reactant. The exothermic reaction generates heat to volatilize the solvent carrier.

First claim

What is claimed is:

1. A self-heating solder flux material comprising:
a solder flux material that includes a solvent carrier;
and a multi-compartment microcapsule that includes:
a first compartment that contains a first reactant;
a second compartment that contains a second reactant; and
an isolating structure separating the first compartment from the second compartment, wherein the isolating structure is adapted to rupture in response to a stimulus, and wherein rupture of the isolating structure results in an exothermic reaction between the first reactant and the second reactant that generates heat to volatilize the solvent carrier.

2. The self-heating solder flux material of claim 1 , wherein the stimulus includes a magnetic field.

3. The self-heating solder flux material of claim 1 , wherein the stimulus includes ultraviolet (UV) light.

4. The self-heating solder flux material of claim 1 , wherein the multi-compartment microcapsule is a shell-in-shell microcapsule comprising an inner shell contained within an outer shell, wherein the inner shell encapsulates the first compartment, wherein the outer shell encapsulates the second compartment, and wherein the inner shell defines the isolating structure.

5. The self-heating solder flux material of claim 4 , wherein magnetic nanoparticles are embedded in the inner shell, and wherein the stimulus includes a magnetic field to dislodge the magnetic nanoparticles from the inner shell to rupture the inner shell.

6. The self-heating solder flux material of claim 5 , wherein the magnetic nanoparticles include magnetite (Fe 3 O 4 ) particles.

7. The self-heating solder flux material of claim 4 , wherein:
the inner shell includes a first material that degrades when exposed to a particular wavelength of ultraviolet (UV) light; and
the outer shell includes a second material that is transparent to the particular wavelength of UV light.

8. The self-heating solder flux material of claim 7 , wherein the first material includes a photodimer.

9. The self-heating solder flux material of claim 7 , wherein the first material includes nitrocinnamate-based material or an azobenzene-based material.

10. The self-heating solder flux material of claim 1 , wherein the first compartment contains a metal, and wherein the second compartment contains an oxidizer.

11. The self-heating solder flux material of claim 1 , wherein the first compartment contains iron, and wherein the second compartment contains hydrogen peroxide.

12. The self-heating solder flux material of claim 1 , wherein the first compartment contains iron and ferric nitrate, and wherein the second compartment contains hydrogen peroxide.

13. The self-heating solder flux material of claim 1 , wherein the solvent carrier includes isopropyl alcohol.

14. The self-heating solder flux material of claim 1 , wherein the heat generated by the exothermic reaction results in a temperature increase that is sufficient to volatilize the solvent carrier but is insufficient to reflow a solder material.

15. A self-heating solder flux material comprising:
a solder flux material that includes a solvent carrier;
and a shell-in-shell microcapsule that includes:
an inner shell contained within an outer shell, the inner shell encapsulating a first compartment that contains a first reactant;
the outer shell that encapsulates a second compartment that contains a second reactant; and
an isolating structure defined by the inner shell, the isolating structure separating the first compartment from the second compartment,
wherein the isolating structure is adapted to rupture in response to exposure to a magnetic field, ultraviolet (UV) light, or a combination thereof, and
wherein rupture of the isolating structure results in an exothermic reaction between the first reactant and the second reactant that generates heat to volatilize the solvent carrier.

16. The self-heating solder flux material of claim 15 , wherein magnetic nanoparticles are embedded in the inner shell, and wherein the magnetic field dislodges the magnetic nanoparticles from the inner shell to rupture the inner shell.

17. The self-heating solder flux material of claim 15 , wherein:
the inner shell includes a first material that degrades when exposed to a particular wavelength of ultraviolet (UV) light; and the outer shell includes a second material that is transparent to the particular wavelength of UV light.

18. A process of utilizing a self-heating solder flux material, the process comprising:
applying a self-heating solder flux material to a region of a printed circuit board,
wherein the self-heating solder flux material includes:
a solder flux material that includes a solvent carrier;
and a multi-compartment microcapsule that includes:
a first compartment that contains a first reactant;
a second compartment that contains a second reactant; and
an isolating structure separating the first compartment from the second compartment;

performing a soldering operation at the region of the printed circuit board; and after performing the soldering operation, exposing the printed circuit board to a stimulus, wherein the isolating structure of the multi-compartment microcapsule is adapted to rupture in response to the stimulus, and wherein rupture of the isolating structure results in an exothermic reaction between the first reactant and the second reactant that generates heat to volatilize the solvent carrier.

19. The process of claim 18 , wherein the stimulus includes a magnetic field, ultraviolet (UV) light, or a combination thereof.

20. The process of claim 18 , wherein the soldering operation includes a hand soldering operation or a rework operation.

Assignees

• IBM

Inventors

• Campbell Eric J
• Czaplewski Sarah K
• Kuczynski Joseph
• Tofil Timothy J

Classifications

• H05K2203/104

  Using magnetic force, e.g. to align particles or for a temporary connection during processing · CPC title

• H05K3/3489

  Composition of fluxes; Application thereof; Other processes of activating the contact surfaces · CPC title

• B23K3/082

  Flux dispensers; Apparatus for applying flux · CPC title

• B23K1/203

  Fluxing, i.e. applying flux onto surfaces · CPC title

• B23K1/0006

  Exothermic brazing · CPC title