Increasing the predictability of AIMSTM measurements by coupling to resist simulations

This paper studies the application of resist models to AIMS [1] images. Measured AIMSTM data were coupled with resist simulations of the Fraunhofer IISB research and development lithography simulator Dr.LiTHO [2] and with a compact resist model developed by Carl Zeiss SMS. Through-focus image data of the AIMSTM are transformed into a bulk image - the intensity distribution within the resist. This bulk image is used to compute the concentration of photo-acid after exposure and the following resist processing. In the result a resist profile is obtained, which can be used to extract the printed wafer linewidth and other data. Additionally, a compact resist model developed by Carl Zeiss SMS was directly applied to the AIMSTM data. The described procedures are used to determine dose latitudes for lines and spaces with different pitches. The obtained data are compared to actual wafer prints for a 1.2 NA system.