| Abstract [eng] |
A printed circuit board is a board made of a hard, thin dielectric material (usually fiberglass) and has electrically conductive copper tracks that replace the wires in a traditional electrical circuit, saving a lot of space. The global reduction in the physical size of electronic devices has led to the fact that we are also seeing a rapid reduction in the size of PCBs. Increasing performance and size requirements have forced PCB manufacturers to make them smaller and smaller, with more densely spaced contact channels and components, and to have more and more layers, i.e., go deep. Vertical channels - vias - are required for communication between the board layers. Due to the aforementioned absolute decrease in sizes, a new type of vias – micro-vias - is becoming popular. Mechanical drills are no longer as efficient a tool as they used to be for larger vias as they often rot and break when they are very tiny, so a laser is chosen for this purpose. The purpose of this work is to study the surface of the sample drilled with femtosecond laser pulses by changing the energy of the laser pulse, the repetition frequency, the number of pulses, compare the results with each other and find the optimal drilling mode, which would result in the smallest deviations and the highest quality craters. After conducting the study, it was found that the optimal drilling mode is when 10 J/cm2 fluence pulses fall on the sample and the lowest repetition frequency used during the study - 18.75 kHz - because drilling with such parameters was the most efficient (the deepest craters) and the highest quality (the smallest errors and thermal effects). |
