doi:10.3850/978-981-08-6555-9_127

ABSTRACT

There are many significant factors in creating microvias using laser direct drilling. We found that surface color; chemical composition, surface roughness and depth of the coating on the surface can affect the ability of the copper surface to absorb CO2 laser energy. Contrary to belief an IGE prepared surface yields consistently larger vias with excellent shape characteristics. In direct comparison Black Oxide, due to the unstable nature of the surface, could not consistently form vias, yielding some 10 –15% smaller vias than the IGE but more significantly the hole shape was also not as good, which has ramifications for subsequent processes.

Keywords: HDI microvias, RF microsystems, Laser technology.

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