The CT 350T is a non-contact double-sided optical profilometer with a 300 mm x-, y- scanning stage. The upper sensor is mounted on a highly accurate z-axis with 100 mm range, while the lower sensor is stationary inside the granite platform. Both sensors collect height data synchronized with x-, y- encoder signals and are aligned axially in order to ensure accurate differential thickness measurements. The software generates 2D profiles and 3D maps simultaneously from the top and the bottom surface and calculates the corresponding total thickness profile or map.
The motion system uses fast and accurate magnetic linear motors. The inspection time is minimized by triggering the chromatic white light sensors at a data rate of 4 kHz.The sensors are available with a z-resolution down to 3 nm and a measurement range up to 25 mm. With an adapter plate on the stage aperture the system can be used as a standard optical surface profilometer which makes the CT 350T the most versatile surface and thickness measurement system. The system is also available in a smaller version as CT 250T with 200 mm travel ideally for 8” wafers or substrates and solar wafers.