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KIRIL A. PANDELISEV, Single Crystal Technologies, Gilbert, AZ, USA

ABSTRACT
The Bridgman Method has undergone many modifications to make it suitable for growth of various crystals for the semiconductor and optical industries. Growth of Calcium Fluoride (CaF2) for193nm and 157nm technology has long been contemplated. Many hundreds of millions of dollars have been spent  to adapt this method for CaF2 in order to grow crystalshaving suitable quality for 193nm and 157nm technology. Nevertheless, the reported crystal yield is still very, very low, in the single digits. This is a very small improvement to the digit fraction (less than 1%) reported by Nestor over ten years ago. At this pace of Bridgman method crystal lens development, one might question the further progress and practicability of this route in the semiconductor industry. Sidestepping CaF2 by using fused silica may suffice for 193nm technology, but it will not serve for 157nm applications. A new crystal lens fabrication method is required. The author, through his patent portfolio and recent conference presentations, introduces methods for high quality, high yield and low capital investment lens fabrication (for simplicity hereinafter referred to as Pandelisev’s method). Heat transfer during the plate growth process and its effects on crystal quality, crystal production yield and crystal size combined with new methods for raw material purification are described. Initial modelling results by Cape Simulations, Inc are included.