Noncontact dielectric constant metrology of low-k interconnect films using a near-field scanned microwave probe

Abstract

We present a method for noncontact, noninvasive measurements of dielectric constant k of 100-nm- to 1.5-μm-thick blanket low-k interconnect films on up to 300mm in diameter wafers. The method has about 10μm sampling spot size, and provides <0.3% precision and ±2% accuracy for k value. It is based on a microfabricated near-field scanned microwave probe formed by a 4GHz parallel strip transmission line resonator tapered down to a few micron tip size.