Automated Wafer Stepping For Very Large Scale Integrated (VLSI) Fabrication
This paper will discuss one of the more advanced automated systems available, the TRE 800 SLR, and its engineering evaluation in the fabrication of VLSI circuits and emphasis will be placed on overlay accuracy including field-by-field registration, matching of steppers and mixing with other aligners.
Abstract
Wafer stepper technology is now accepted as an important tool in the generation of VLSI circuits. More than with most products, the evolutionary nature of steppers is clear. The early systems were based on mask-making equipment, lacked automation and had few features suitable for the VLSI production environment. Systems have changed substantially since then and are now more compatible with manufacturing requirements. This paper will discuss one of the more advanced automated systems available, the TRE 800 SLR, and its engineering evaluation in the fabrication of VLSI circuits. Emphasis will be placed on overlay accuracy including field-by-field registration, matching of steppers and mixing with other aligners. Finally, an automated track process for this stepper will be described.