Junki Min

Ultra-miniaturized and surface-mountable glass-based 3D IPAC packages for RF modules

This paper demonstrates ultra-miniaturized RF passive components integrated on thin glass substrate with small Through Package Vias (TPVs) to realize 3D Integrated Passive and Actives Component (IPAC) concept. Miniaturization is achieved through; a) ultra-thin glass, b) low-loss thin dielectrics and c) small TPVs. Inductors, capacitors and low pass filters functioning in the frequency range of 0.8 GHz to 5.4 GHz were modeled and fabricated between thin dielectric layers on 100 μm thin glass, and then assembled on PCB through BGA interconnections. The simulated results corroborated well with measured results, providing guidelines for RF module fabrication.

Modeling, design and demonstration of integrated electromagnetic shielding for miniaturized RF SOP glass packages

This paper demonstrates, for the first time, an integrated trench-based shielding for electromagnetic interference (EMI) isolation between components in an ultra-miniaturized radio frequency (RF) package. A novel component-level shielding structure is explored and developed using metallized trenches formed in the build-up layers of ultra-thin glass substrates. Through full-wave electromagnetic (EM) simulation, the coupling between different passive structures are compared. Additionally, the shielding effectiveness of trench-based structures are compared with traditional via-based shields. Further, the shield effectiveness of different magnetic and non-magnetic shield materials are compared through analytical modeling. Based on these modeling results, a representative shield structure is designed, fabricated and characterized to correlate its performance with simulations. It is observed through measurements, that package-integrated trench-based shields provide up to 25dB more lateral isolation than via-arrays.

Magnetic Materials and Design Trade-Offs for High Inductance Density, High-Q and Low-Cost Power and EMI Filter Inductors

This paper investigates the trade-offs in inductance density and quality factor of inductors with and without magnetic-cores through modeling, design, fabrication and model validation through characterization. Two type of inductors, one for power-supply and the other for EMI filters, are investigated. Parametric analysis was performed to study the enhancement in inductance density without compromising the current handling and efficiency. For EMI filter inductors, the inductance and quality factor (Q) were improved by 13X and 4X respectively with and without magnetic cores. For power inductors, the inductance and quality factor were improved by 5X and 1.6X respectively. The fabricated magnetic core inductors achieved 5X reduction in thickness, compared to the stage-of-the art air-core inductors which use multilayered and thick solenoid.

Design and Demonstration of Ultra-Thin Glass 3D IPD Diplexers

This paper demonstrates, for the first time, 3D integrated passive device (IPD) diplexers on ultra-thin glass substrates for wireless local area network (WLAN) application in mobile devices. The designed LC-based diplexer was composed of a low-band filter and a high-band filter, built on ultra-thin glass substrates. The two filters were designed on each side of the glass substrate and interconnected by through-package-vias (TPVs) to form a 3D IPD. Ultra-thin and low-loss dryfilm dielectrics were utilized for improved electrical performance as well as to achieve high-density of passives integration. The demonstrated 3D IPD diplexer is 3-4X thinner than current LTCC devices, with lateral dimensions of 1.1mm x 1.3mm in a thickness of 200μm resulting in a low insertion loss of less than 1dB for pass bands and more than 24dB stop-band rejection.

Modeling, design and demonstration of ultra-miniaturized glass PA modules with efficient thermal dissipation

This paper addresses the thermal dissipation of power amplifier (PA) chips, which is one of the biggest challenges in the development of ultra-miniaturized glass-based RF modules. Glass packages with 3D or double-side active and passive integration offer the best miniaturization and performance enhancement for RF modules because glass has ultra-low loss, dimensional stability for precision thinfilm components, ability to process through-vias in large panels to reduce cost. However, glass is a poor thermal conductor. Cooling of the high-power PA die with integrated miniaturized RF modules is, therefore, a key challenge. This paper provides extensive modeling studies of RF power amplifier modules with copper thermal vias in ultra-miniaturized glass, without additional process steps. It considers various power amplifier design options such as: Si vs. Silicon-on-Insulator (SOI); location of die hotspot; via geometry; and conformal vs. fully-filled vias, and provides optimal design recommendations with modeling and analysis.

Modeling Design Fabrication and Demonstration of RF Front-End Module with Ultra-Thin Glass Substrate for LTE Applications

This paper demonstrates, for the first time, an integrated radio frequency (RF) front-end module (FEM) with precision matching circuits in ultra-miniaturized glass substrates for LTE applications. Through full-wave electromagnetic (EM) simulations, electrical performance of these glass-based long term evolution (LTE) packages is compared with traditional RF modules with surface mount devices (SMDs), and organic laminates with embedded passives and actives. RF front-end modules with 3D or double-side thin film passive components on glass-based substrates are fabricated and characterized to correlate their performance with EM simulations.

Improving Power Integrity by Using Magnetodielectric Absorbers Along the Perimeters of Printed Circuit Boards

Maintaining low and smooth impedance over a wide range of frequency is one of the main issues in designing high-speed digital systems or mixed signal integrated circuits. Cavity resonances of a printed circuit board coupled with discontinuous return current paths, series inductance of the power distribution network, and parasitic inductance make potentials at power/ground planes unstable. One possible solution to improve power integrity and electromagnetic interference is to utilize a magnetodielectric absorber on the perimeter of the board. A mode-matching method and an impedance boundary condition are employed to obtain a computationally inexpensive model of the system. A contour plot of transfer impedance versus normalized surface impedance is introduced to provide useful information for determining the most suitable absorber. Numerical and measurement results are discussed. The results from the proposed modeling agree with those from the measurement and the simulation. The selected absorber effectively reduces selfimpedance and transfer impedance at resonant frequencies, but resonances are not completely eliminated at low frequencies due to the low loss of the absorber.