Patent ID: 6800141
Filing Date: 2004-10-05
Classification: C09D,C11D,C23G,Y10S

Abstract:
A method for removing rosin flux residue formed on electronic assembly surfaces, interfaces and under device surfaces during high temperature solder interconnections which comprise the steps of:(a) providing a first cleaning composition which comprises a first water insoluble hydrophobic solvent with a surface active agent, wherein said hydrophobic solvent are propylene glycol alkylethers represented by the formula ROâ€”(C3H6O)Nâ€”C3H6OH wherein R is selected from the group consisting of propyl, butyl, pentyl and isobutyl and where N=0 to 4; (b) immersing the assembly in said first cleaning composition and soaking the assembly in said first cleaning composition for 10 to 20 minutes at 50 to 90Â° C. with intermittent agitation; (c) removing the assembly from said first cleaning composition; (d) immersing the assembly in a second cleaning solvent, without adding surfactant, which comprises water insoluble hydrophobic propylene glycol alkylethers represented by the formula ROâ€”(C3H6O)Nâ€”C3H6OH wherein R is selected from the group consisting of propyl, butyl, pentyl and isobutyl and where N=0 to 4 and soaking the assembly in said second cleaning solvent for 5 to 20 minutes at 50 to 90Â° C. with agitation; (e) removing the assembly from said second cleaning solvent; (f) applying a third cleaning composition which comprises a hydrophilic water soluble propylene glycol methyl ether solvent at 50 to 75Â° C. to the assembly for 5 to 10 minutes; (g) applying a water use at approximately room temperature to 65Â° C. to the assembly for approximately 5 to 10 minutes; and (h) drying the assembly and thereby complete the removal of the flux residue from the assembly surfaces, interfaces and from under the device surface.