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

TL;DR

This paper introduces a noncontact, noninvasive microwave-based method for accurately measuring the dielectric constant of thin low-k interconnect films on large wafers, enabling precise characterization without damage.

Contribution

The paper presents a novel near-field microwave probe technique with micron-scale resolution for dielectric constant measurement of thin films on large wafers.

Findings

Achieves <0.3% precision in dielectric constant measurement.

Provides <2% accuracy for films 100 nm to 1.5 μm thick.

Applicable to wafers up to 300 mm in diameter.

Abstract

We present a method for noncontact, noninvasive measurements of dielectric constant, k, of 100-nm- to 1.5-\mu m-thick blanket low-k interconnect films on up to 300 mm in diameter wafers. The method has about 10 micron 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 4 GHz parallel strip transmission line resonator tapered down to a few-micron tip size.