Optical Coatings Patterning
The flat-panel-display and photovoltaic industry permanently presses on the development of new laser technologies. Patterning of thin films on various substrates is a top one in the time of booming market for LCD, PDP and OLED displays and large investments into photovoltaics. Picosecond lasers may be used in processing on a variety thin films and multi-layers on rigid and flexible substrates.
The indium-tin oxide (ITO) film with the thickness of 150 nm on a glass substrate was patterned with the picosecond laser radiation. Low absorption of the material in the infrared and visible spectrum impeded clean removal of the material. On the other hand, the film was completely ablated with the low energy density using the UV radiation, which is well absorbed by the oxide film.
The obtained minimal width of grooves at the top of the ITO film was 7 μm. The trench had a regular shape with smooth both walls and the bottom. The width at the bottom was only 2.87 μm. The dimensions are reasonable for a high-density packing of the connector lines in OLED or RFID. High quality processing of ITO without ridges is only possible using the laser with both a short wavelength and a short pulse duration.