The FRT CWL IR bases on the spectral analysis of the interference of beams reflected at the boundaries of a transparent film on a substrate. The intensity of the reflected radiation shows a periodical waviness pattern that is dependent on the thickness of the film. From the intensity pattern and with the known refractive index of the film material the film thickness is calculated. This method is also used in the FRT CWL FT sensor, which, however can only be used for films up to 250 µm thickness, because of its white light source. The CWL IR has been developed especially for samples which are opaque in the VIS but are transparent in the near IR, like many semiconductor materials. The CWL IR comes with a narrow band source with 1300 nm center wavelength.
	non-destructive, non-contact measurement measurement of semiconductors with infrared light high measuring range high local resolution	Download Options   Product Sheet   Company Brochure
	measurement of materials, that are opaque in visible light but are transparent in the near infrared measurement of film-thickness of objects on opaque carrier materials local measurement of film-thickness in the semiconductor industry film-thickness mapping with MicroProf® and MicroGlider® systems
	Sensor CWL-IR 250 CWL-IR 500 CWL-IR 1000 Measuring range (min-max)1 28 - 1100 µm 34 - 1900 µm 60 - 3500 µm Film-thickness resolution 50 nm 100 nm 200 nm Lateral resolution 6.5 µm Working distance 23.5 mm Measuring angle 90° ± 5° Light source SLD 1300 nm Interfaces USB 2.0, RS232, analog  1 At an refractive index of n=1