Method for characterizing thermal properties of e.g. mirror substrate, from quartz glass i.e. titanium silicate glass, for manufacturing e.g. extreme UV light-mirror, involves detecting upper-surface waves by ultrasonic receiver

摘要

The method involves stimulating upper-surface waves (9) in a sample (1) by injecting ultrasonic waves (U) into the sample using an ultrasonic transmitter (4a). The upper-surface waves are detected by an ultrasonic receiver (4b) for determining titanium dioxide content within a near-surface volume region (2). The ultrasonic transmitter and receiver are moved over an upper surface (1a) of the sample, and arranged at a fixed distance to each other, where the distance is about 30 mm. Injection of the ultrasonic waves is enabled by wedge shoe-type parts (8a, 8b). An independent claim is also included for a method for selecting a slug as substrate for manufacturing a mirror.