Low-Loss On-Chip Passive Circuits Using C4 Layer for RF, mmWave and Sub-THz Applications

This paper presents the recent developments of on-chip low-loss passive circuits using customized patterns that are fabricated with standard bump process (C4) for RF, mmWave and sub-THz applications in Intel16 technology. Due to the large cross-sectional area of the C4 layer, passive devices with ultralow-loss and high current capacity can be built. Common high frequency passive components such as inductors, transmission lines, and antenna arrays have been implemented as proof of concepts. To the authors’ knowledge, this is the first time that passive circuits are demonstrated using the bump layer directly. These low-loss passive components enable high performance, innovative circuits and systems in a variety of applications.