project 'µ': Ilfa invests in new production technology

Modern layouts require drilled hole diameters below 120 µm at which mechanical drilling and plugging reach their limitations. Therefore, German PCB manufacturer Ilfa invested in a Combidrill laser machine. This machine, also called dual laser machine, uses two different laser sources. With a UV laser (wave length 355 nm) the copper layers can be trepanned. Organics, ceramics and glass can be removed very well with the second laser source, a CO2 laser (wave length 10.6 µm) without perforating the underlying copper layer. "We had a longer search at Ilfa and we waited for a dual laser machine to be available on the market which offered comparatively small dimensions, a good beam quality, and a software perfectly compatible with the mechanical drilling machines existing at Ilfa. With this machine, we are now capable to drill more than 150 holes per second from one copper layer to the next with diameters from 80 µm to 120 µm. The very high mix of the different materials FR4, PTFE filled HF materials and ceramically filled HF materials can be drilled without problems. The process parameters for the laser drilling were found very fast in each case. The main work consisted in the adaptation of the whole process chain subsequent to the laser drilling process, i.e. the desmearing, the direct metallisation, and the through plating process. Shape and surface condition of the drilled hole differ between mechanically and laser drilled holes. With the optimised processes we obtain an outstanding drilling and through plating quality despite the fact that we are able to drill now 100 times faster than before", explains Dr. Andreas Gombert, Managing Director and Head of Engineering / F&E at Ilfa.