Broadband Thin-Film Transmission-Line Characterization for Accurate High-Frequency Measurements of On-Wafer Components

Abstract

A high-frequency fine-pitched (i.e., very narrow line width) thin-film transmission line (TL) characterization technique is presented. A new dielectric permittivity determination technique for thin-film TL structures is developed. Multi-layered mixed dielectric materials are then accurately characterized in a broad frequency band, to be followed by the TL characterization. For experiments, various lengths of TL and extra patterns were designed and fabricated by using both a ${\hbox{0.18-}}\mu{\hbox{m}}$ SK Hynix CMOS process and ${\hbox{0.13-}}\mu{\hbox{m}}$ Samsung CMOS process. S-parameters for the test patterns were measured by using a vector network analyzer from 10 MHz to 50 GHz. It is shown that not only the inherent de-embedding problems associated with wafer-level high-frequency characterizations can be conveniently eliminated, but also the frequency-variant characteristic impedance of a thin-film TL can be readily determined using the proposed technique. It can be exploited for accurate high-frequency wafer-level component characterizations including miniaturized transistors, frequency-variant interconnect lines, and other circuit components.