Single-shot, high repetition rate metallic pattern transfer

A flexible high-speed fabrication of relatively thick (about 1 mu m) and large (about 130 x 120 mu m) thin film metal pads with a laser-induced forward transfer technique using femtosecond laser pulses (fs-LIFT) will be discussed. Possible applications an thickening of thin film contact pads for wire bonding, the deposition of solder pads or the frequency or electrical resistance tuning of discrete devices. The use of ultrashort laser pulses instead of nanosecond laser pulses reduces the melting problem, increases the quality and the adhesion of the transferred metal pads and allows the transfer of complete disks out of thin films ( < 1 mu m thickness). The combination of ultrashort laser pulses with a pre-structuring of the metal film improves the geometry of the pads and increases the film disk thickness (> 1 mu m). As a example the transfer of 0.76- and 1.8 mu m thick gold/tin disks with a single laser pulse are presented. (C) 2000 Elsevier Science B.V. All rights reserved.