Oct. 8, 2002 – Corning, NY – Corning Inc. has received a US patent for a calcium fluoride (CaF2) lens blank that supports the advancement of CaF2 materials for the 193nm and 157nm microlithography systems.
CaF2 represents the next-generation optical material for semiconductor manufacturing applications.
This fluoride crystalline material has outstanding optical properties including high internal transmission and long-term laser durability at the fluences used in stepper lenses. Until now, the industry has faced difficulties manufacturing a CaF2 lens blank with specifications suitable for the microlithography process.
“The production of CaF2 lens blanks is notoriously difficult,” said Michael Pell, senior scientist at Corning’s Fontainebleau Research Center in Avon, France. “Growing the crystals is an extremely slow and challenging process-the smallest impurities can result in a complete loss of the product batch.”
While still in the early stages of development, this patented material will enable Corning to manufacture CaF2 lens blanks suitable for the 157nm technology node. In addition to meeting industry demand for high performance optical materials, this technology will play a critical role in manufacturing faster and more powerful integrated circuits.