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U.S. Department of Energy
Office of Scientific and Technical Information

Ion chromatography in the manufacture of multilayer circuit boards

Conference ·
OSTI ID:5890482

Ion chromatography (IC) has proven useful in analyzing chemical solutions used in the manufacture of multilayer circuit boards. IC provides results on ions not expected in the production solutions. Thus solution contamination, and breakdown products can be monitored in every phase of the circuit board manufacturing. During the first phase, epoxy laminates experience an etchback, first in chromic acid, which can be analyzed for trace chloride and sulfate, then in ammonium bifluoride/HCl, which can be analyzed for fluoride and chloride. Following a wet blasting to roughen up the surface, 20 ..mu..in. of copper are deposited using an electroless bath. Again, IC is applicable for monitoring formate, tartarate, and sulfate levels. Next, an acid copper bath is used to electroplate the through holes with 0.001 in. of ductile copper. This bath is analyzed for trace chloride. Photoimaging is then performed, and the organic solvents used can be assayed for trace ionic chloride. Finally, a fluoroboric acid-based tin-lead bath is used to deposit a solderable alloy. This bath is analyzed for total fluoroborate, tin, and lead. In addition, mobile phase ion chromatography (MPIC) is used to monitor the nonionic organic brighteners in the baths. 11 refs., 3 figs.

Research Organization:
Allied Corp., Kansas City, MO (USA). Bendix Kansas City Div.
DOE Contract Number:
AC04-76DP00613
OSTI ID:
5890482
Report Number(s):
BDX-613-3798; CONF-8709185-1; ON: DE88002428
Country of Publication:
United States
Language:
English