A single metrology tool solution for complete exposure tool setup

Abstract

Numerous metrology tools, techniques and methods are used by the industry to setup and qualify exposure tools for production. Traditionally, different metrology techniques and tools have been used to setup dose, focus and overlay optimally and they do so independently. The methods used can be cumbersome, have the potential to interfere with each other and some even require an unacceptable amount of costly exposure tool time for data acquisition. In this work, we present a method that uses an advanced angle-resolved scatterometry metrology tool that has the capability to measure both CD and overlay. By using a technique to de-convolve dose and focus based on the profile measurement of a well characterized process monitor target, we show that the dose and focus signature of a high NA 193nm immersion scanner can be effectively measured and corrected. A similar approach was also taken to address overlay errors using the diffraction based overlay capability of our metrology tool. We demonstrate the advantage of having a single metrology tool solution, which enables us to reduce dose, focus and overlay signatures to a minimum.