| Abstract: | A rapid and easy screening test was applied to assess the capability of various formulated primers to reduce the defect of pink rings in multilayer printed circuit boards. The mixtures of silanes with multifunctional silanol groups (crosslinkers) and 3-glycidoxypropyl-trimethoxysilane 1 Systematic name: 3-(2,3-Epoxypropoxy)propyl-trimethoxysilane. (referred to as silane C) or N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane 2 Systematic name: 3-N-2-aminoethyl]aminopropyl-trimethoxysilane. (silane B) were proved to be effective in reducing the pink rings. The performance of the mixed silanes using silane A and crosslinkers with aromatic groups were better than other formulated primers which was partly attributed to less amounts of hydrophilic groups and better integrity in the primer films. A developed primer consisting of siloxane compounds had the best performance. The online test confirmed the results from the screening test and demonstrated the feasibility of the designed screening test in assessing the performance of primers. The results of FTIR spectroscopy and thermogravimetric analyses confirmed that the effective primers coated on the copper oxides could improve the curing reaction and the thermal oxidative stability of the epoxy/CuO system. |
