Fully Integrated On-Chip Inductors: An Overview

This paper presents an overview and State-of-the-Art of fully integrated inductors with common fabrication processes used for implementation of these structures into a chip. The first step is an overview of fabrication technologies that starts with standard CMOS general purpose processes expanded by Far-BEOL and substrate alteration process (SOI, Silicon Embedded, TSV, TGV, PTH, Core Insertion); and continues to advanced process nodes like SMMT and Bond Wire utilization. Then, an overview of fully integrated inductor structures consists of selected topologies with notable parameters achieved in last few years. Critical parameters of integrated inductors include: inductance L
DC
, inductance density LA, quality factor Q, self-resonant frequency FSR and series resistance R
DC
. These parameters are as important as the purpose and fabrication process.