Characterization, modeling and optimization of 3D embedded trench decoupling capacitors in Si-RF interposer

Abstract

Integrated trench high density MIS (Metal Insulator Semiconductor) capacitors in Si-interposer are of great interest as they provide decoupling in a smart way using the third dimension of the silicon substrate. However, the use of various highly integrated passive components on the same Siinterposer is challenging regarding wide frequency band performances and signal integrity. Both aspects are addressed in this paper based on 300 kHz-20 GHz vector network analyzer measurements on 3D 80 nF/mm 2 decoupling capacitors produced by IPDIA on a high resistivity substrate. Firstly, a scalable 1 MHz-10 GHz wideband model of a 3D capacitor in the 100 pF-10 nF range is developed. Secondly, 3D electromagnetic simulations of substrate and capacitive coupling between 3D capacitors using guard ring are presented. All simulations show good agreement with measurements. To the best of our knowledge, this is the first time that a wideband mathematical model as well as an RF crosstalk study have been published on embedded trench decoupling capacitors. IntroductionThe benefits of having a close proximity between potential noise sources and decoupling capacitors are well known. High density integrated decoupling capacitors are very promising components for the requirements of low crosstalk and signals coupling levels in mixed-circuit and high density 3D interposer applications as illustrated in figure 1.

High capacitance density highly reliable textured deep trench SiN capacitors toward 3D integration

“…Si trench capacitors with high-quality insulator films have been explored for this purpose. [14][15][16][17][18][19][20] For much higher capacitance density, Si trench capacitors with very deep trench (DT) depth such as 70 μm or more have been explored to increase the effective area. Furthermore, for compact system development, these capacitors should be able to be integrated with LSI using 3D integration technologies such as through-silicon via, micro-bumps and hybrid bonding.…”