Recent Advancements in Motion Control with Long-Term Nanoscale Stability, Including a Novel, Comparative Validation Technique

摘要

Advancing needs for positional resolution in semiconductor microlithography, data storage and related industries have been accompanied by commensurate needs for positional stability. For example, a great deal of technological development and facilities investment has been devoted to devising and deploying vibration isolation technologies which shield sensitive equipment from environmental perturbations such as seismic disturbances from machinery and personnel. Similarly, stage brakes and clamping air-bearings have also proven valuable for improving the stability of certain automated assemblies, and motion-driven structural disturbances and resonances have been pacified by careful motion-profile optimization and by employing nullifying technologies such as Input Shaping®.All these benefit nano-sensitive applications in many ways, ultimately in terms of yield and throughput. But another, insidious instability process can also bedevil sensitive applications: quasi-asymptotic, nanoscale settling due to lubricant flow processes in drive, alignment and adjustment elements such as leadscrews and micrometers. This is slow, progressing at the nanoscale over many minutes. Since conventional position-metrology instrumentation is typically less stable than recent process tolerances over the timescales involved, quantification of these issues has been lacking.Here we review:1. An emerging class of motion drive technologies capable of nanoscale resolutions over long travels, including in challenging environments (ultra-clean, high vacuum, fieldlesson-magnetic, and/or EUV);2.A novel metrology approach which allowed, for the first time, comparative quantification of long-term, nanoscale drift/settling behaviors at the nanoscale, and3.A family of actuation mechanisms that mitigates drift issues by eliminating their source.