3D Integrated High-Precision Passives on Thin Glass Substrates for Miniaturized and High-Performance RF Components

Abstract

Double-side or 3-D integration of high-precision and high-performance bandpass and lowpass filters that are interconnected with through-vias were designed and demonstrated on 100-micron thin glass substrates for ultra-miniaturized diplexer components. A novel process for achieving high precision with large-area fabrication was developed to achieve much improved tolerance in electrical performance. High-precision, high quality factor, and high component densities with thin-film layers on glass were used to realize innovative topologies on glass for high out-of-band rejection and low insertion loss. Low-loss 100-μm thick glass cores and multiple layers of 15-μm thin polymer films were used to build the filters on substrates. The demonstrated diplexers have dimensions of 2.3 ×2.8 ×.2 mm. Aided by the dimensional stability of glass and process control with semiadditive patterning, the performance of the fabricated filters showed excellent correlation with the simulation. The impact of process-sensitivity analysis on diplexer performance was also analyzed. Finally, a unique and innovative process solution was demonstrated to control the process deviation and achieve good diplexer tolerance. The performance deviation was controlled by ~3.5X with the new process.