High-throughput microvia drilling in advanced packaging materials using state-of-the-art industrial UV lasers

Advanced packaging is playing an increasingly crucial role in maximizing the potential of today’s highest-performing integrated circuit (IC) devices. An important ingredient in advanced packaging is the dielectric build-up material known as ABF (Ajinomoto Build-up Film), a matrix material comprised of silica microspheres suspended in epoxy resin. To form electrical connections between layers, laser via hole drilling is performed. The latest packaging technologies require drilling of so-called microvias, those having diameters at or below ~50 µm, and doing so generally requires shorter-wavelength pulsed UV lasers. Here we present laser blind microvia drilling results in various ABF laminates, including those for via diameters approaching 10 µm. Drilling throughputs are characterized for short and ultrashort pulse (USP) UV laser sources, and the importance of pulse energy, average power, and fluence management are discussed in the context of maximizing throughput with today’s high-power industrial lasers.