Copper Direct Drilling With TEA<tex>$hbox CO_2$</tex>Laser in Manufacture of High-Density Interconnection Printed Circuit Board

Microdrilling of Through-Holes in Flexible Printed Circuits Using Picosecond Ultrashort Pulse Laser

“…Moreover, there is very low absorption ratio for Cu at the near-infrared wavelength, which makes the drilling unsuitable directly using CO 2 laser in FPCs. Therefore, a coating metal is required on the surface of Cu resulting in complex processing [6], or the Cu layer is stripped using other lasers and then another layer is processed using CO 2 lasers [7]. Moreover, the obtained hole diameters using CO 2 lasers are approximately 75~150 μm which could not be further decreased [8].…”

A Parameters Optimization of the CO₂ Laser Drilling Process for HDI Microvia Fabrication

“…Now UV laser and CO 2 laser are two general kinds of laser drilling method being used in PCB production [1,2].The UV laser could be used to cut high quality blind vias through shorter wavelength and higher energy but the processing time is too long which is not conductive to a large number of production [3,4]. In contrast,the CO 2 laser is much more widely used by PCB production manufactures for its high-speed, high-efficiency and low-cost [5].Most CO 2 laser can produce infrared radiation at wavelengths around 9.4µm and 10.6 µm [6,7] and the laser energy is much lower than UV [8]. During via drilling process CO 2 laser vaporizes and decomposes the substrate by thermal ablation [9].Many scholars have done lots of works about the laser drilling technology, but merely mentioned about how the different laser parameters effect on the quality of blind vias [10].…”