RF Performance of CMOS Technology Passive Devices Using 3D Hybrid Bonding Interconnections at mm-Wave Frequencies

This paper investigates the impact of 3D hybrid bonding (3D-HB) interconnections on the performance of passive components, including transmission lines, inductors, capacitors, and transformers, at mm-wave frequencies up to 220 GHz. Measurements of the 3D-HB transmission lines highlight very low single-transition losses (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&lt;0.2 \text{dB}$</tex> at 100 GHz). A comparison between 2D planar and 3D-HB integrated designs shows a negligible impact of the 3D-HB technology below 100 GHz. At higher frequencies, in particular for inductors, the self-resonant frequency is shifted about <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1 0}$</tex>% lower for the 3D-HB structure than for the 2D design. Finally, measurements of a transformer based on two single-turn (one turn per bonding side) spirals demonstrate high inductive coupling up to 65 GHz. These results underline the interest of 3D-HB interconnections for compact, efficient RF designs, enabling seamless integration and reduced interconnect losses in mm-wave applications.