Nanometric Metal-Film Thickness Measurement Based on a Planar Spiral Coils Stack

This paper presents a sensor composed of a differential arrangement of coils capable of measuring nanometric metallic film thickness. Experimental results achieved aluminum thickness measurements as low as 20 nm with a sensitivity of 3.8 mV/nm. This makes this sensor a flexible, nondestructive, and cheap alternative for metallic thickness measurement down to nanometric scale.