U.V. Repair Process And Formulation
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-15
Protective coatings for circuit lines on printed circuit boards occasionally experience defects which require repair. Glass master defects or debris on glass masters may result in voids in the coating over the circuit lines. Blisters may be caused by different process fluids. These defects may be repaired by using an epoxy formulation as a touch-up material. As a Vacrel (E. I. duPont de Nemours & Co. trademark) repair material, the epoxy touch-up has several limitations. The application process is complicated and lengthened by the inability of the material to withstand vapor blast. The required one hour thermal cure at 140oC is a severe stress on the circuit board materials. The repair material must withstand wavesolder, hot water, immersion tin, and must bond to the coating and to substrate copper.