We have upgraded the AIT performance to improve imaging stability, illumination uniformity, and resolution.

The company that originally constructed the AIT experimental chamber went bankrupt in 2005, before the tool was delivered to LBNL; and when it was finally assembled, it failed to meet spec (i.e. it failed to perform as intended). Over the next 3 years, numerous critical upgrades were performed by the project scientists and CXRO engineers and technicians, bringing the tool up to today's high levels of performance. SEMATECH's supportive backing (including the strong project leadership of Obert Wood and Stefan Wurm and Hakseung Han) allowed the project to succeed through its difficult startup period.

The imaging performance of the AIT has undergone major overhauls in two steps (shown below). In 2005, the AIT was able to perform imaging for the first time, but vibration limited its ability to see features below 1 μm, or perform repeatably. In 2006 the vibration problems were solved using a new focus-control actuator, yet the newly sharp images revealed problems with image distortion, lens aberrations, and illumination non-uniformity. In 2007 a complete overhaul of the imaging optics was performed with the installation of the parts shown below. The result has been clear, sharp, repeatable imaging performance close to the diffraction-limited performance goals of the tool.

The parts used in the major upgrades recently performed to overcome the AIT's initial design limitations are shown in the figure below. These include a vibration quenching, z-position (through-focus) actuator, and a complete re-design of the image-projection optics, including the zoneplate and an ultra-flat 45° turning mirror. These small components fit within the 0.7-in. (1.8-cm) gap between the mask and the Schwarzschild objective that provides the AIT's mask illumination.

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