Product Code: ICAL05_M107

Patterning of ITO Film by Femtosecond Laser Ablation
Authors:
Dave Farson, Ohio State University; Columbus OH USA
Hae Choi, Ohio State University; Columbus OH USA
Kwang Kim, LG Electronics; Pyungtaek-si Kyunggi-Do Korea
Presented at ICALEO 2005

Indium tin oxide (ITO) is commonly used in flat panel display applications. The ITO needs to be patterned to form pixels and direct write laser ablation is widely used for this purpose. In this investigation, femtosecond laser patterning of ITO was studied to identify laser processing parameters which cleanly ablated ITO with a minimum of damage to substrate glass and surrounding ITO. Soda-lime glass with an ITO film of approximately 150 nm thickness was used for experiments. The pulse energy was attenuated with a thin film polarizers and was focused by a microscope objective. Ablation was carried out at a sufficiently high panel scanning speed that single ablation spots could be studied by AFM scans. Single ablation spots in ITO with width/depth ranging from 800nm/70nm to 2400nm/150nm were produced at fluences from 1.3 to 17 J/cm^2. For uncoated glass, ablation depths ranged from 30nm to 120nm at fluences from 5 to 17 J/cm^2. Thus, the amount of energy to ablate a unit volume of material was measured to be 2.4um^3/uJ and 0.95 um^3/uJ for glass substrate and ITO, respectively. At a laser fluence of 1.3 J cm-2, lines were ablated at 1.55mm/sec scanning speeds without substrate damage .