The Fabrication and Reliability of a Photovia Test Vehicle for MCM-L Applications

The design and fabrication of a test vehicle for photovia technology are described in this paper. The test vehicle consists of two copper layers interconnected through a photovia dielectric layer using FR4 as a substrate. Various test structures have been fabricated to assess the technology as well as for reliability tests. Thermal cycling, thermal shock, reflow excursion, and 85°C/85%RH ageing were performed to test the reliability of electrical continuity and insulation. Peel strength was measured after fabrication as well as after 150°C annealing and reflow excursions. Initial results reveal that photovias may be more reliable than conventional through vias.