Design and implementation of high-Q passive devices for wireless applications using system-on-package (SOP) based organic technologies

Ceramic and silicon substrate interconnection and packaging technologies have been used for many years in many different types of applications such as integrated passive devices and modularization. This is especially true for the wireless handheld market segments. Although more cost-effective, there is an inherent inertia that has built up towards using organics for similar applications and remains a technology of choice primarily for circuit boards, IC packaging and flex applications. There is a perception that organic technology is inadequate and lower in performance compared to ceramics and silicon technologies for RF and mixed signal integration. This research discusses the feasibility of obtaining high Q embedded passive components for standards such as the Bluetooth (2.45GHz) and PCS (1.9GHz) using organic substrates. A system-on-package (SOP) approach has been taken at the heart of which is a low-cost, low-temperature, multi-layer organic sequential build-up (SBU) technology. Inductors and capacitors greater than 1 nH and 1 pF, respectively, with Q-factors in the range of 60–400 have been implemented for frequencies from 1–10 GHz. Robust methods to characterize the materials and process have been developed. Fast and accurate methods have been developed to model and optimize embedded passives such as inductors, capacitors, filters and resonators. Bandpass filters for several different applications that perform similar to or better than ceramic filters have been implemented for various applications. The filters are smaller compared to the cavity filters and much easier to construct and fabricate. Devices such as oscillators and amplifiers with all embedded passive devices have been implemented which helps achieve the noise specifications for various wireless communication standards.