Inspection of laser ablated transparent conductive oxide thin films by a multifunction optical measurement system

Abstract

In recent years, laser ablation method has been increasingly used in the touch panel industry. Touch panel devices are produced by applying laser ablation process on transparent conductive oxide (TCO) thin films coated on glass substrates. The pattern and the surface profile of the transparent conductive layer on glass substrates after laser ablation are crucial on the quality of the touch panel. Therefore, a self-assembled multifunction optical measurement system was employed to investigate the details of the surface of the test specimen of the TCO thin films after ablation. The system integrates both optical microscope and white-light scanning interferometer to inspect the specimen under the same field of view. The transparency of the test specimen was inspected by the optical microscope to examine the uniformity of the gray levels throughout the ablated region. The depth of the ablated thin films and whether the thin films are fully cut can be determined from the surface profile obtained from the white-light scanning interferometer. Based on the aforementioned experimental results, the self-assembled multifunction optical measurement system is full of potential to be used to determine the manufacturing parameters in laser ablation process.