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32 The PCB Magazine • July 2014 F e a t u r e Abstract A novel ceramic-functional-particle-filled polymer composite material has been devel- oped for the use either in discrete elements on the PCB or in being embedded within the packaging substrate for high-frequency circuit applications. This material provides the desired properties such as low loss at high frequencies (about 0.002 or less up to 10GHz) and high di- electric strength, among other improved prop- erties. The electrical properties were influenced significantly by the ceramic-functional-particle (type and particle size/distribution in the poly- mer matrix). Their contributions to the electric strength and temperature stability of capaci- tance (which is an important material issue for practical device application) will be discussed. In addition, capacitance tolerance for manufactur- ing an embedded RF capacitor will be presented in terms of etching uniformity to minimize the variation of the capacitor electrode areas. I. Introduction Organic-based dielectric materials has been explored for the use either in discrete passive components on the PCB or in being embedded within the packaging substrate as part of RF/mi- crowave circuits [1–4] . Using ceramic-functional- particles (fillers), filled polymer composite ma- terial is merely a convenient and inexpensive way (to compete with ceramic chip capacitors) achieving low ESR (equivalent series resistance), high SRF (self-resonant frequency) for RF ca- pacitor application that can support frequen- cies well above 1GHz. Besides, embedding fill- ers into the polymer enhances properties of di- electric materials (by optimizing filler chemistry and its distribution in the polymer matrix) such as temperature stability of capacitance for high precision RF circuit and dielectric strength (the by Jin-Hyun Hwang, John Andresakis, Ethan Feinberg, Bob Carter, Yuji Kageyama, and Fujio Kuwako oaK-MitSui technologieS RF Capacitor Material for Use in PCBs