Highly accurate and precise measurement technique for effective exposure dose

The recent advantage of a measurement technique for effective exposure dose (EED), which is performed by monitoring the residual thickness of the photoresist, has enabled us to elucidate errors consuming the dose margins. The EED describes total thickness variation caused by non-uniformity of illumination, post exposure baking, and non-uniformity of development, and so on. In this paper, the principles for EED measurement are discussed. The accuracy and precision of this technique is shown. Furthermore, the dynamic range of this technology is considered.