Low Temperature Co-fired Ceramic LTCC Application Testing Alternative

Passive component implementations are undergoing a dramatic density increase with the application of multi-layer materials such as low temperature ceramic composites, high density flexible circuits, and imbedded circuits within PC boards. This has migrated into RF applications such as Blue Tooth wireless communications enabling small cost effective solutions pervasive in equipment such as laptop computers, cellular phones, printers, palm pilots, etc. With the increased passive component density comes a RF application testing difficulty that is complicated further by the need to include active devices or integrated circuit components with the passive monolith to complete the RF application. This paper describes an alternative to RF applications testing for multi-layer implementation where the material and process parameters are measured on a generic structure using mixed-mode four-port parameters. What results is a non-destructive probe test using off-the-shelf four-port vector network measurement and analysis equipment, for obtaining electrical parameters such as dielectric constant and loss tangent, screened metal conductivity and reactive value, and physical parameters such as dielectric thickness, conductor width, and layer alignment. With the measurement of material and process parameters the multi-layer wafer can be monitored during the manufacture process and prior to committing high cost integrated circuits and other components. A common test structure can be applied across a wide variety of RF applications with measurement frequency being defined by the application. What this means is the RF testing of high-density components such as LTCC become generic independent of the particular electrical function.