High Speed, High Accuracy Stage for Advanced Lithography. Phase I
Abstract
The overall program goal is to develop an integrated stage and metrology system for microlithography, based on the use of an XY encoder grid, meeting the following specifications: (a) 12" x 12" coverage, (b) accuracy of +/- 2.5nm or better, (c) operable at a speed of 1 meter/sec, and (d) active control of all 6 degrees of freedom. To this end, the Phase I program had goals of (1) finding one or more suppliers of high-accuracy grids; (2) grid-based measurement repeatability of +/- 2.5nm or better, (3) ability to work at speeds of up to 1 meter/sec, and (4) development of a short-range optical sensor for servo control of the nominally fixed degrees of freedom (Z, theta(x), and theta(y)). With the exception of the velocity specification, these Phase I goals were all met. We were able to work at velocities of up to 790mm/sec, and can readily get to 1 meter/sec by upgrading the speed of the A/D's in our phase processor. Measurement repeatability of +/- 2.5nm was achieved in an environment where the turbulence-limited repeatability of a laser interferometer was on the order of 10nm to 20nm. We found the Etec ALTA laser-writer to be the best machine for making accurate grids.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 17, 1998
- Accession Number
- ADA347314
Entities
People
- Michael Hercher