Scanning microwave microscopy of aluminum CMOS interconnect lines buried in oxide and water

Using a scanning microwave microscope, we imaged in water aluminum interconnect lines buried in aluminum and silicon oxides fabricated through a state-of-the-art SiGe BiCMOS process. The results were compared with that obtained by using atomic force microscopy both in air and water. It was found the images in water was degraded by only approximately 60% from that in air.