Laser prototyping of multilayer LTCC microwave components for system-in-package applications

This study describes the fabrication of multilayer microwave components in low temperature co-fired ceramic (LTCC) technology using a laser prototyping method that requires no masks or photolithographic steps. Multilevel inductors, metal-insulator-metal capacitors and substrate integrated waveguides (SIWs) have been demonstrated. Optimisation of the laser machining parameters for the fabrication of microvias and micro-channels for the components is investigated. Using a 1064-nm IR laser, vias and channels with widths smaller than the thickness of the substrate have been achieved using the proposed multi-step process. Microvias with a diameter and separation of 75 and 50--m, respectively, have been realised by optimising the laser fluence and processing cycles. Micro-channels having widths of 30-100--m have also been demonstrated and used as the side walls for SIWs. The proposed fabrication technique offers a useful method for the rapid prototyping of multilayer LTCC modules.