Mask inspection

About: Mask inspection is a research topic. Over the lifetime, 1072 publications have been published within this topic receiving 8696 citations.

A novel concept for actinic EUV mask review tool using a scanning lensless imaging method at the Swiss Light Source (Withdrawal Notice)

Abstract: Publisher's Note: This paper, originally published on April 17, 2014, was withdrawn at the author's request on May 25, 2016

Application of spatial filtering subtraction to thin film and integrated circuit mask inspection.

Abstract: Studies have been performed to investigate the application of spatial filtering subtraction to mask inspection. By using a grating at the spatial frequency plane, images can be subtracted to give a display of errors on a black background. Results indicate that this technique could have application for integrated circuit and thin film mask inspection provided there are two or more repeated patterns on the mask.

Impact of B4C capping layer for extreme ultraviolet mask on the sensitivity of patterned mask inspection using a projection electron microscope

Abstract: The inspection sensitivity of a patterned extreme ultraviolet mask with B4C-capped multilayer (ML) was investigated using a simulated projection electron microscope (PEM) image. Extrusion and intrusion defects with 16-nm size were detected with their intensity of >10 times the standard deviation of the background level on a half-pitch 64-nm line-and-space pattern. The defect detection sensitivity in this case was higher than that of a Ru-capped ML sample and has a potential to meet the requirement for beyond 16-nm node generation from the standpoint of patterned mask inspection using the PEM technique. These results indicate that the B4C capping layer, besides its good durability, has an advantage for high sensitivity of patterned mask inspection. The optimal condition of the incident beam energy was found to be 500 and 1,000 eV for the samples of B4C-capped ML and B4C-buffered Ru-capped ML, respectively. The sensitivity of defect detection was strongly affected by the difference of secondary electron emission coefficients (SEECs) between the absorber layer and capping layer. However, the small incident beam energy was found to be preferable when the SEEC difference was relatively high.

EUV mask and wafer defectivity: strategy and evaluation for full die defect inspection

Abstract: Over the past few years numerous advancements in EUV Lithography have proven its feasibility of insertion into High Volume Manufacturing (HVM).1, 2 A lot of progress is made in the area of pellicle development but a commercially solution with related infrastructure is currently unavailable.3, 4 Due to current mask structure and unavailability of a pellicle, a comprehensive strategy to qualify (native defects) and monitor (adder defects) defectivity on mask and wafer is required for implementing EUV Lithography in High Volume Manufacturing. In this work, we assess multiple strategies for mask and wafer defect inspection including a two-fold solution to leverage resolution of e-beam inspection along with throughput of optical inspection are evaluated. Defect capture rates for inspections based on full-die, critical areas based on priority and hotspots based on design and prior inspection data are evaluated. Each strategy has merits and de-merits, particularly related to throughput, effective die coverage and computational overhead. A production ready EUV Exposure tool was utilized to perform exposures at the IBM EUV Center of Excellence in Albany, NY for EUV Lithography Development along with a fully automated line of EUV Mask Infrastructure tools. We will present strategies considered in this study and discuss respective results. The results from the study indicate very low transfer rate of defect detection events from optical mask inspection. They also suggest a hybrid strategy of utilizing both optical and e-beam inspection can provide a comprehensive defect detection which can be employed in High Volume Manufacturing.