Laser-induced congruent forward transfer of SiO x -layers

Laser-induced forward transfer of inorganic oxide films is demonstrated using the example of SiO (x) -layers. SiO (x) with x < 2 is strongly UV-absorbing, so that excimer lasers are suited for inducing transfer. When the distance between donor and receiving substrate is reduced to zero, congruent transfer is possible; i.e. the deposited geometry corresponds exactly to the ablated spot. This zero-distance configuration is accomplished by using a polydimethylsiloxane (PDMS) film as the receiving substrate, which is cast directly on the SiO (x) -coated fused silica donor substrate. After curing of the PDMS, the SiO (x) -layer is irradiated by a single 25 ns-KrF-excimer laser pulse through the donor substrate. At a fluence of 300 to 600 mJ/cm(2) predefined areas of a 830 nm thick SiO (x) -layer are cleanly transferred to the PDMS-substrate, i.e. the irradiated parts of the layer stick to the PDMS-surface after peeling it off. This way spot arrays or stripes with lateral dimensions of a few mu m as well as free-standing grids can be generated. By multipulse exposure, the fabrication of stacks or bridges is possible.