Analysis of novel technology for power and signal integrity using a metal particle conductive layer

Abstract

Power integrity (PI) has been an important technological issue in the field of electronic circuits and systems. It has been addressed in important papers using several different approaches [1][2]. The latest concept of the best PI condition is a low impedance between the power and ground lines or planes, that can be maintained regardless of the clock frequency, even in the GHz region. A novel technology was used in our previous study, in which a metal particle conductive layer (MPCL) was used instead of a copper plane [3][4]. This structure improved the PI for any clock frequency, particularly in the GHz region. The MPCLs consist of micrometer sized silver flakes (SF) and binder resin. In this study, we used an epoxy as a binder for conductive paste, polyimide (PI) copper clad laminate (CCL) and 60 µm thickness prepreg as the inner dielectric of test coupons. These are general-use material so that they can be made easily, and apply to printed circuit boards (PCBs) and package substrates (PKGs). It has been found from transmission line test coupon measurements, that energy propagation time and frequency characteristics, are strongly affected by the metal particle content and chemical composition. From power/GND plane test coupon measurements, MPCL can reduce Z11 about 70% compared with copper plane from 1 to 5GHz frequency region. In this paper, we will show the detailed phenomena of MPCL, exceeding the region of usual transmission line theory, and MPCL adaptability to commercial materials of PCB and PKG.