Digital Microfabrication by Laser Decal Transfer

Laser decal transfer is a novel direct-write technique that allows the digital microfabrication of thin film-like patterns or structures on many substrates without the use of lithography and etch steps. Laser decal transfer is based on the non-phase transforming laser-induced forward transfer of complex suspensions or inks. This type of laser transfer allows the direct printing of materials such as metallic nano-inks from a donor substrate to a receiving substrate while maintaining the size and shape of the area illuminated by the laser transfer pulse. Consequently, this technique does not exhibit the limited resolution, non-uniform thickness, irregular edge features and surrounding debris associated with earlier laser forward transfer techniques. Laser decal transfer can be used to make continuous and uniform metallic lines typically 5 micrometers or less in width, and a few hundred nanometers in thickness. These lines are of similar scale as patterns generated by lithographic techniques. After transfer, the lines are cured either thermally or by a CW laser to become electrically conductive. In situ laser curing results in lines with resistivities as low as 3.4 mu Omega cm. This novel laser direct-write technique is ideally suited for digital microfabrication applications and can be used for the development, customization, modification, and/or repair of microelectronic circuits.