Metal treatment – Compositions – Fluxing
Patent
1990-09-17
1992-06-16
Rosenberg, Peter D.
Metal treatment
Compositions
Fluxing
148 24, 148 25, B23K 3534
Patent
active
051222000
ABSTRACT:
Solder pastes having vehicles including formic acid-soluble organic acids as fluxing agents are described. Fluxing agents may be compounds of the formula: ##STR1## where R is an electron withdrawing group. In one embodiment, R is selected from the group consisting of fluorine, chlorine, bromine, iodine, sulfur, hydroxyl, nitrile, and benzyl. Other suitable formic-acid fluxing agents include, but are not limited to, adipic acid, acrylic acid, polyacrylic acid, methacrylic acid and polymethacrylic acid. The compounds clean oxides from the printed circuit boards (PCBs) under assembly and then volatilize leaving a residue to be cleaned away. The cleaning step involves rinsing with formic acid. No undesired residue remains indicating that the organic acids of the invention are effective in cleaning boards. Such acid fluxing agents can be used mixed with typical solder components, such as lead/tin solder pastes, or applied topically to solders, such as solder balls; both techniques permit the assembly of PCBs more easily with high quality bonds, and with little or no residue. Malic acid is a preferred organic acid fluxing agent. The formic acid cleaning step may be followed by a water rinse.
REFERENCES:
patent: 3235414 (1966-02-01), Marks
patent: 3796610 (1974-03-01), Sarnacki et al.
patent: 4216035 (1980-09-01), Bakos
patent: 4960236 (1990-10-01), Hedges et al.
Davis James L.
Landreth Bobby D.
Mulligan Robert J.
Nounou Fadia
Pennisi Robert W.
Dorinski Dale W.
Motorola Inc.
Rosenberg Peter D.
LandOfFree
Method of cleaning printed circuit boards using formic acid does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of cleaning printed circuit boards using formic acid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of cleaning printed circuit boards using formic acid will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1751345