Back-End-of-Line Quadrature-Clocked Voltage-Dependent Capacitance Measurements

We compare different dc current-based integrated capacitance measurement techniques in terms of their applicability to modern CMOS technologies. The winning approach uses quadrature detection to measure mutual Front-End-Of-Line (FEOL) and Back-End-Of-Line (BEOL) capacitances. We describe our implementation of this approach, Quadrature-clocked Voltage-dependent Capacitance Measurements (QVCM), and its application to 45 nm node BEOL: wire capacitance variability measurements for analog design, and capacitive test structure to measure the effect of metal pattern density on Chemical-Mechanical Polishing (CMP) and Reactive Ion Etching (RIE).