Development of Optical System Utilizing Mirror and Reflector

As semiconductor product development progress and pattern become increasingly scaled down, there is a demand for overlay margins in the sub-nanometer range. To adjust overlay margins, the technology to identify and correct overlay gradients on the wafer is essential. In high volume manufacturing (HVM), observing overlay value for all targets on the wafer entails a trade-off with productivity. Fast measurement performance is necessary to measure dense targets. We demonstrate a simulation process of utilizing equipment's optical system for faster measurements. The objective is to increase the optical transmission of light intensity to improve measurement time.