In this paper, we describe the development, and application, of a suite of high-frequency electromagnetic wave (RF) based techniques to probe material and structural changes in copper interconnects in TSV enabled 3-D integrated circuits during high-temperature storage. Illustratively, we discuss how RF insertion loss (S21) based-techniques have been used to study the oxidation of copper interconnects in 3D-ICs. We compare the microwave insertion loss results to those from DC measurements and discuss the advantages of the former technique over the latter. Using electrodynamic simulations, we discuss the partitioning of microwave signal loss in corroded copper interconnects, and the significance of the roughness at the air-copper oxide interface.
2020 INTERNATIONAL CONFERENCE ON MICROELECTRONIC TEST STRUCTURES, April 6-9, EDINBURGH, UNITED
April 6-9, 2020
metrology, microwave, corrosion, interconnect