Application results at 193nm: lithography emulation by aerial imaging and supplementary high resolution measurements

Abstract

The AIMS fab tool is an aerial image measurement system for ArF-lithography emulation and is in operation worldwide. By adjustment of numerical aperture, illumination type and partial coherence parameter to match the conditions in 193nm steppers or scanners, it can emulate lithographic exposure tools for any type of reticles such as binary masks, OPC and phase shift structures, down to the 65nm node. The AIMSTM fab 193 allows the rapid prediction of wafer printability of critical features, such as dense patterns or contacts, defects or repairs on masks without the need to prepare real wafer prints using the stepper or scanner. Recently, a high resolution mode has been introduced based on a sophisticated microscope objective, characterized by a high numerical aperture (NA) and large working distance that allows working with pellicle mounted mask. With this lens system a high contrast image with resolution down to 150 nm lines and spaces (L/S) on mask has been demonstrated. In addition to the AIMSTM through-focus mode for printability which is optically equivalent to the latent image in the photo resist of a wafer, the high resolution mode allows the imaging of mask structures in focus and at printing wavelength to review defects or repairs. Such viewing capability is also helpful at the binary stage of a first writing step in the mask manufacturing process. In this work we will present application results for defects and critical features using both, aerial imaging and high resolution mode.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.