Study On The Technology And Application Of The Embedded Capacitor Of Printed Circuit Board

The technology of capacitor embedded into the printed circuit boards is an important basis for electronic products to the development of multi-function, high performance and small size, and it’s also the critical part of the technology of embedded passive component. In this paper, the technology and application of embedded capacitor were studied.This paper mainly studies the technology of embedded capacitor by etching thin film materials. It’s very difficult for the processing by double-side etch due to the thin dielectric layer of materials, so it is necessary to control key construction processes strictly for ensuring product quality. Pre-Compensation for the pattern is required when making the inner pattern transfer to reduce the effect of harmomegathus which caused in the process of lamination and keep size stability. Pre-compensation is mainly concerned with the laminated plate number and layout, and the less laminated plate number is, the lager the shrinkage will be. Guide board should be needed in the process of DES and oxide Adding support when making metallographic can guarantee the quality of metallographic of thin PCB.The reliability of embedded capacitor product was evaluated by the withstand voltage test, reflow test and thermal cycling test, and capacitance value was measured before reflow and after reflow. It passed 2000 V withstand voltage test, and there was no quality defects in the hole of 0.25 mm pore size, 0.8 mm hole spacing after the process of six times reflow with Temperature of 260 ℃. The quality of hall was well after 100 times thermal cycling test, and the rate of change of the hall’s resistance was less than 3%. The rate of change of the capacitance value was less than 3% after six times reflow, and it indicates conventional process of SMT almost does not affect the capacitance value.Through-hole copper filling with bi-directional pulse plating was an application of the embedded capacitor materials. This paper discus the technology of through-hole copper filling which the diameter of through-hole is 150μm and thickness of core is 84μm with bi-directional pulse plating. The method used is to form “butterfly” structure in the through-hole by multiple flash-plating, and then for the copper filling process. The result showed that the method of using through-hole copper filling with bi-directional pulse plating is feasible in the absence of special hole filling plating line.Based on the research of the technology of embedded capacitor, reliability test and the through-hole copper filling with bi-directional pulse plating, reliable products were obtained in practical applications.