Visualization and damage due to nano-dendrite defects in metal-insulator-metal capacitors

Abstract

Metal-insulator-metal (MIM) capacitors have found wide use in analog/mixed-signal IC products. However, a variety of extrinsic defects can occur during manufacture. Surface roughness and particles have been proposed as major sources of defects, but there have been no reported methods to visually elucidate how the defect interacts with its surroundings or correlation of the defect with the failure mode. Defect visualization can turn out to be crucial in finding the origin of defects and improving the process. There are unique challenges in visualizing tiny defects in MIM capacitors, because an electrical analysis can easily destroy a defect by interlayer fusion and voiding, or separation. This paper deals with the analysis technique used to nondestructively identify the defects, and then reviews the detrimental aspects of a new type of defects by Transmission Electron Microscopy/Energy Dispersive X-ray (TEM/EDX) analysis.