THE USE OF MODAL ANALYSIS IN THE DEVELOPMENT OF ADVANCED LITHOGRAPHY MACHINES

摘要

The use of modal analysis as a diagnostic tool is rapidly increasing. This paper describes a unique application of this technology in the analysis of an advanced lithography machine. This machine, a "step-and-repeat" system, uses a photographic process to print electronic circuit patterns on wafers with resolutions in the realm of nanometers. Consequently, it is imperative for the structural response to be controlled during the machine's normal operations. Modal, vibration, and timing control experiments were conducted in order to assess the various design features which provide optimum machine performance. It was determined that the vibration sources and the stiffness of the machine components are tailored to complement each other such that all potential problem areas are avoided. In addition, special design features are employed to allow the machine to quickly optimize conditions - such as wafer residual motion and positioning error - prior to wafer exposure. The ultimate goal of this investigation is to improve the reliability of lithography equipment and to aid in the development of more advanced machines.