Measurement of Ultrathin Film Mechanical Properties by Integrated Nano-scratch/indentation Approach

摘要

The thickness and property measurements of thin films on substrates are crucial for wide range of applications. Classical techniques have relied on various physical properties to identify film thickness, independent of its mechanical properties. Here, a new experimental technique is devised to evaluate the film thickness, its flow stress and its stiffness. The technique utilizes a combination of nano-scratch and dynamic stiffness measurements carried out by a nano-indenter. The technique relies on measuring the depth variation of normal and tangential forces, and indentation modulus. These combined measurements are calibrated through a simple statically admissible stress model to yield the unknown quantities. The measurements are ascertained by XPS film thickness measurements, and reasonably agree with the finite element predictions. The technique is applied to study the formed oxide nano-layer during copper chemical mechanical planarization.