GENETIC STRAIN OPTIMIZATION FOR IMPROVING THE PRODUCTION OF RIBOFLAVIN

摘要

PROBLEM TO BE SOLVED: To form visibility-excellent printed dots while the adhesion of printed foreign particles to a semiconductor wafer is suppressed. ;SOLUTION: A semiconductor wafer 1 is held on a wafer stage 2 and irradiated with a laser beam 3 at prescribed printing positions from over the wafer 1. A ring-shaped exhaust part 10, which encircles a region (printing region) for a printing with the laser beam 3, is provided in close proximity to the upper part of the wafer 1. The exhaust part 10 sucks gas in it, whereby the exhaust part 10 can efficiently recover foreign particles generated in the case where the beam 3 is strong.;COPYRIGHT: (C)2003,JPO