The ZEISS AIMS™ platform is well established as the industry standard for qualifying the printability of mask
features based on the aerial image. Typically the critical dimension (CD) and intensity at a certain through-focus
range are the parameters which are monitored in order to verify printability or to ensure a successful
repair. This information is essential in determining if a feature will pass printability, but in the case that the
feature does fail, other methods are often required in order to isolate the reason why the failure occurred,
e.g., quartz level deviation from nominal.
Atomic force microscopy (AFM) is typically used to determine physical dimensions such as the quartz etch
depth and sidewall profile. In addition the AFM is a useful tool in monitoring and providing feedback to the
repair engineer, as the depth of the repair is one of the many critical parameters which must be controlled in
order to have a robust repair process.
Carl Zeiss, in collaboration with Photronics-nanoFab, demonstrate the ability to use AIMS<sup>TM</sup> to provide
quantitative feedback on a given repair process; beyond simple pass/fail of the repair. Using the ZEISS MeRiT<sup>®</sup>
repair tool as the example, the AIMS<sup>TM</sup> technique is used in lieu of an AFM to determine if repaired regions are
over-etched or under-etched; and further to predict the amount of MeRiT<sup>®</sup> recipe change required in order to
bring subsequent repairs to a passing state.