Excessive dark loss has been observed along the edge nearest the lid of aged chemically amplified resist blanks, which was traced to organic acid contamination evolving from the acrylic plastic lid of the shipping box. Thermal Gravimetric Analysis (TGA) combined with Fourier Transform Infrared Spectroscopy (FTIR) of the shipping box lid material have proven useful in identifying that organic acid evolves from the plastic at 110°C. An alternative plastic shipping material offered by the supplier was tested with the same analysis technique and no organic acid was evolved during the test. To accelerate the aging effect, both lid materials were baked in an oven for 4 days, and no excessive dark loss was observed with the new shipping material. An evaluation with chemically amplified resist comparing storage in the original shipping materials at ambient conditions vs. storage in dry nitrogen demonstrate that nitrogen storage improves, but does not eliminate, the excessive dark loss from the original plastic lid material.

Date Published: 8 November 2005
PDF: 8 pages
Proc. SPIE 5992, 25th Annual BACUS Symposium on Photomask Technology, 59923C (8 November 2005); doi: 10.1117/12.632223

Published in SPIE Proceedings Vol. 5992:
25th Annual BACUS Symposium on Photomask Technology
J. Tracy Weed; Patrick M. Martin, Editor(s)