Accuracy and fabrication cost of optical masks continue to be major concerns for the semiconductor industry. While immersion and other process technologies promise to extend optical lithography down to the 45nm node, the resulting technical and commercial requirements for the mask fabrication process become increasingly difficult to achieve. Potential solutions that are readily available to wafer fabricators are either too expensive to deploy or have not been commercialized for mask manufactures- up until now. Mobile metrology has the inherent ability to provide the required measurement accuracy, on any tool, at a low cost of ownership. This paper will discuss the application of a self-contained, wireless SensorPlate for providing process optimization and control within a leading mask blank manufacturing facility. Three critical process steps are characterized: Quartz Cleaning, Chromium Physical Vapor Deposition, and Photoresist Post-Applied Baking. Process optimization was completed to achieve improved performance of the mask blank product.
In this paper, we introduce MaskTemp<sup>TM</sup>, a novel wireless metrology system to record in-situ the temperature of a reticle during processing. In combination with OnWafer Technologies' AutoCal bake plate optimization software, MaskTemp provides a quick and easy method to fingerprint and optimize the within-plate temperature uniformity of advanced PEB plates.Thermal data is collected across multiple bake plates, and we show substantial within-plate and plate-to-plate improvements in advanced multi-zone hot plates calibrated with conventional methods.