High-Q Embedded Passives on Large Panel Multilayer Liquid Crystalline Polymer-Based Substrate

This paper presents high-Q embedded passives on a multilayer liquid crystalline polymer (M-LCP)-based substrate for a low-profile, compact, mixed-signal system integration with high performance. A low loss and a low water absorption are advantages of LCP. It is also lower-cost material than other high-frequency materials such as low-temperature cofired ceramic (LTCC) due to its compatibility to printed wiring board (PWB) process. Low loss characteristics of LCP provide high-Q passives such as inductors, capacitors, and matching networks. Seventy-six inductors and sixteen capacitors were characterized from three different 9 in times 12 in multilayer LCP panels. Two different locations from each board were chosen to preliminarily validate the large panel process of the M-LCP substrate. The highest quality factor (Q) of 164 was achieved with 2.55 nH at 5.05 GHz. The inductors range from 1.45 to 23.11 nH and Qs range from 43 to 164. Inductors in various embedded layers were characterized for realization of 3-D integration in multilayer LCP substrate for multiband applications. To remove the parasitics from pads and interconnections, a two-step de-embedding technique was applied. The model-to-hardware correlations are presented in this paper. Twelve 3-D capacitors were also designed and characterized, which provide more than double the capacitance of standard capacitors. Low-loss filters and baluns at 5 GHz were simulated and measured using the designed high-Q passives. The designed high-Q embedded passives on M-LCP-based substrates provide a systematic 3-D integration method for achieving low-profile, high-performance, and compact modules.