Enhanced cleaning for water-soluble flux soldering

Patent metadata

Field	Value
Publication number	US-9818717-B2
Application number	US-201615052461-A
Country	US
Kind code	B2
Filing date	Feb 24, 2016
Priority date	Feb 24, 2016
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

An approach to provide an electronic assembly process that includes receiving at least one electronic assembly after a solder reflow process using a Sn-containing solder and a water-soluble flux. The approach includes baking the at least one electronic assembly in an oxygen containing environment and, then cleaning the at least one electronic assembly in an aqueous cleaning process.

First claim

The invention claimed is:

1. A method for an electronic assembly process comprising:
receiving at least one electronic assembly after a solder reflow process using a Sn-containing solder and a water-soluble flux;
baking the at least one electronic assembly in an oxygen containing environment for a range of bake times between fifteen minutes and one hundred and eighty minutes; and
cleaning the at least one electronic assembly in an aqueous cleaning process.

2. The method of claim 1 , further comprising baking the at least one electronic assembly in the oxygen containing environment within a range of temperatures from 40° Celsius to 180° Celsius.

3. The method of claim 1 , further comprising baking the at least one electronic assembly in the oxygen containing environment for at least one of 60° Celsius for thirty minutes and 120° Celsius for three hours.

4. The method of claim 1 , further comprising baking the at least one electronic assembly for a range of temperatures from 60° Celsius to 120° Celsius for a corresponding range of bake times from thirty minutes to three hours.

5. The method of claim 1 , wherein the water-soluble flux is any suitable water-soluble flux used in an electronic packaging assembly.

6. The method of claim 1 , wherein the at least one electronic assembly includes one or more of a semiconductor module, a flip chip semiconductor module, a BGA module, and a printed circuit board.

7. The method of claim 1 , further comprises the water-soluble flux including at least one or more of the following an activator, a solvent, a vehicle, and one or more additives.

8. The method of claim 1 , wherein the solder reflow process further comprises forming a solder interconnection from one or more of a plated solder bump, a solder ball, a solder bump deposited by an evaporation process, and a solder paste.

9. The method of claim 1 , wherein receiving the at least one electronic assembly after solder reflow process includes at least one of a semiconductor module, a BGA module, and an assembled printed circuit board.

10. The method of claim 1 , wherein the at least one electronic assembly using a Sn-containing solder includes at least one of an electronic assembly using a Sn—Pb solder, a lead-free solder, and other Sn-containing solder.

11. The method of claim 1 , wherein the at least one electronic assembly includes a lead-free flip chip semiconductor module.

12. The method of claim 1 , wherein baking the at least one electronic assembly in an oxygen containing environment further comprises baking the at least one electronic assembly to oxidize Sn(II) carboxylate flux residue into Sn(IV) carboxylate flux residue.

13. The method of claim 1 , further comprises receiving a flip chip semiconductor module that uses the solder reflow process with a lead-free solder,
wherein, the water-soluble flux includes a set of one or more fluxes including Indium® WS-3555.

Assignees

• IBM

Inventors

• Bureau Charles C
• Duchesne Eric
• Lee Kang-Wook
• Paquin Isabelle
• Veljanovic Dragoljub

Classifications

• B23K35/262

  Sn as the principal constituent · CPC title

• C23G1/00

  Cleaning or pickling metallic material with solutions or molten salts (with organic solvents C23G5/02) · CPC title

• B23K1/203

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

• B23K35/362

  Selection of compositions of fluxes (B23K35/365, B23K35/368 take precedence) · CPC title

• B23K35/3618

  Carboxylic acids or salts · CPC title