Kiril A. Pandelisev, Single Crystal Technologies, Gilbert, AZ, USA 

ABSTRACT 

The Bridgman Method [1] has undergone many modifications to make it suitable for growth of various crystals for the semiconductor and optical industries. Growth of Calcium Fluoride (CaF₂) for 193nm 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 crystals having suitable quality for 193nm and 157nm technology [2]. Nevertheless, the reported crystal yield is still very, very low, in the single digits [3]. This is a very small improvement to the digit fraction (less than 1%) reported by Nestor [4] 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.