Measurement Technique for Quantification of Registration Errors to a Fixed Primary Standard for Masks and Wafers Processed by Step and Repeat Lithographic Tools
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
A technique is disclosed for measuring the registration errors of lithographic systems using the axial symmetry of patterns. These measurements are for the purpose of providing standards for the selection and matching of optical systems. Following are the steps used for measuring the registration errors. 1. Design a symmetric overlay having a monitor test site. 2. Generate the test site patterns on a 10X segment. Use a fused silica substrate for greater precision and accuracy. 3. Contact print this segment pattern onto another fused silica plate for checking reticle errors. 4. Use a comparator (and/or electrical tester) to measure the registration errors within the segment by rotating the segment using the symmetry of the pattern. This will provide a measurement of the reticle errors. 5. Use an enlarged (i.e.