Drilling Microvias

Drilling of microvias in various materials with hole diameters down to 50 μm

Multilayer PCB technology requires reliable and economic production technology for through and blind holes to establish an electrical connection between the various layers of the multilayer. High density interconnects (HDI) in particular are currently characterised by connecting holes with diameters down to 50 μm. Holes larger than 200 μm will continue to be created mechanically as before. Laser processing is an efficient technology for the series production of microvias with diameters smaller than 200 μm.

Drilling with a UV-laser involves only one sequence of operation to drill through the copper covering layer as well as the epoxy resin and glass fibres if present. When doing so, the laser energy is controlled so precisely that the lower conducting layer is only slightly roughened and cleaned at the same time. Unlike CO₂ and hybrid laser systems, the LPKF MicroLine Drill therefore does not require any upstream etching process or a second laser.

UV-laser processing is characterised by short pulse lengths in the nanosecond range with high pulse peak powers. Combined with a higher level of material absorption compared to longer wavelengths, this means that material ablation is carried out with considerably less thermal influence on the material. This avoids the delamination of copper and dielectric, the pink ring effect is significantly minimised as well. The laser processing therefore guarantees excellent hole quality combined with high throughput.

Microvias can be drilled in RCC, FR4 and FR5, as well as Teflon® and Thermount®.


Read further under Advantages UV laser drilling