Precision Flexure Mechanisms in High Speed Nanopatterning Systems

Semiconductor wafer nanolithography machines integrate nano-scale precision mechanisms with advanced optical and mechatronic modules to achieve highly controlled nanopatterning capability for fabricating advanced integrated circuits, photonics, and optoelectronic devices. The machines achieve their precision by combining the use of highly repeatable nano-resolution actuators and motion systems, and on-tool precision calibration that is typically required for assembled systems since the sub-system machining precision is inherently insufficient.

In this article, precision flexure mechanisms used in advanced photolithography and imprint lithography systems are discussed and compared. The main difference between them is that nanoimprint lithography mechanisms need to possess high dynamic load carrying capability in addition to precision performance. The article first provides a brief review of quasi-static precision mechanisms in advanced optical instruments and tools. The article next discusses flexure mechanisms used for calibration and nano-precision real-time alignment for a UV nanoimprint process. These mechanisms require specialized designs as they need to support high dynamic loading encountered during the high-speed separation (demolding) process in imprint lithography. Finally, imprint template flexures - that have to satisfy very stringent precision and dynamic loading requirements - are described in detail. Specific design requirements of template flexures include (a) providing selectively compliant tilting about remote compliant centers, (b) possessing an order of magnitude higher stiffness in other axes, and (c) avoiding mechanical and thermal distortions from mounting of the template chuck to the supporting column.