Laser machining of microvias and trenches for substrate integrated waveguides in LTCC technology

In this paper, the fabrication of microvias and trenches for substrate integrated waveguides (SIWs) in low temperature co-fired ceramic (LTCC) technology is studied using a commercial laser PCB prototyping system. It is shown that by careful control of the laser beam around the edge of the via, clean holes can be produced. Vias with diameter of 75 μm and trenches with width of 60 μm are demonstrated. The effects of laser parameters in making vias and trenches are investigated. The process is then utilized to demonstrate LTCC SIWs operating in the 25-40 GHz range with low loss. It is confirmed that a rows of via-holes can achieve the same performance as solid sidewalls.