High-precision positioning technology

As rapid progress continues to be made in the development of more densely integrated semiconductor components, the attainment of ultraprecise chip-component positioning, to the order of a nanometer, looms as a major barrier to further advances. In this field, however, fast operation as well as extraordinary precision is needed if high-quality productivity is to be attained. As one promising means of achieving a workable compromise, we have developed a coarse-fine-drive system, combining a ball-screw mechanism which drives a table at high speed, and a cylindrical piezoactuator for additional high-resolution positioning. The control unit, featuring friction compensation and proportional derivative (PD) control, is optimally designed on the basis of simulation studies. The result is a positioning table which enables both the ultra-precise positioning needed for producing even finer LSI patterns and high-speed operation for higher productivity.