Product Code: ICAL07_M104

Precise Patterning of Thin Films with Picosecond Fiber Laser
Authors:
Jari Sillanpää, Corelase; Tampere Finland
Kalle Klä-Jarkko, Corelase; Tampere Finland
Harry Asonen, Corelase; Tampere Finland
Presented at ICALEO 2007

During the last few years fiber lasers have become the hottest topic in material processing applications. In macromachining applications they have been able to take market share from conventional lamp pumped YAG-lasers while also enabling totally new applications that so far have not been in the reach of conventional laser tools. Micro manufacturing processes are the fastest growing applications for lasers due to the dynamic consumer electronics market. Major drivers here are cell phones and flat panel displays, especially TVs. New production methods for flexible PCBs, joining processes for ultra-fine pitch in-terconnections and thin film patterning methods all call help from laser based tools! Different kind of metal or metal oxide films are used by electronics and semiconductor industries. This paper focuses on the structuring of very fine features in thin films utilizing an industrial mode-locked ultra short pulsed high repetition rate fiber laser. The differences between kHz and MHz lasers are compared. At Corelase we conducted series of tests to demonstrate improved quality and capability to process thin films. For example processing of indium tin oxide (ITO) thin film on polymer is demonstrated. 20µm groove was processed to 20nm thick ITO layer with 0,55W@2MHz. The processing was done without any damage to the polymer underneath. We will show that the picosecond fiber laser operating with MHz repetition rate is very suitable for processing thin films with high processing quality combined with industrial grade high processing speeds.