Laser Induced Forward Transfer (LIFT) has been attracting much attention in a wide variety of industry fields because LIFT can directly write the micro deposited pattern on the substrate The purpose of this study is to investigate morphology of deposited copper pattern with conditions of laser irradiation.

In our experiments, the ultrashort laser system (LIGHT CONVERSION, PHAROS, PH2-1mJ-SP) which generates 1030 nm, 190 fs to 10 ps, single pulse to 1 MHz ultrafast laser pulses, was used. The sample to be processed was thin copper on glass substrate. Another glass substrate was located on the opposite side of the copper layer with the gap of 11 μm. The laser pulses were focused on the thin copper layer with an aspherical lens with a focal length of 11 mm and a numerical aperture of 0.3. Then, the thin copper layer was transferred to the surface on another glass substrate. With scanning speed of 0.1 mm/s, the sample was translated 5 mm in the y direction. The deposited copper pattern on the surface of another glass substrate was measured with a confocal scanning microscope (KEYENCE, VK-X3000). We investigated processing parameters such as pulse energy and repetition rate. Figure 1 shows the confocal laser scanning microscope image after LIFT with a pulse energy of 150 μJ and a repetition rate of 50 kHz. The morphology was smooth half circle. In the presentation, we will introduce the relationship between morphology of copper wire and processing parameters in details.