Study of degradations in PCB interconnections for high frequency applications

In this paper, we investigate a second-category method to evaluate the degradations of high frequency interconnections on FR4 boards. More than the defects location, the purpose of the present study is to distinguish the effects of the copper metallization corrosion (oxidation, delamination, etc..) from the /spl epsiv//spl tau/ sensitivity to moisture absorption of the laminated substrate. The test structures are based on elementary resonant circuits, which have been submitted to different accelerated aging tests. The resonance characteristics of these structures are very sensitive to the technological parameters and allow an early detection of damages.