RF properties of carbon nanotube / Copper composite through silicon via based CPW structure for 3D integrated circuits
Paper in proceedings, 2019

The development of integrated circuits (ICs) has seen exponential growth in performance over the last couple of decades and has pushed the boundaries for how we use our electronics in our daily lives. The scaling of ICs, and therefore also the performance development, is now starting to slow down when the physical designs are reaching critical dimensions where quantum effects starts to become noticeable. One proposed route to circumvent these issues for a continued scaling is based on the implementation of 3D integration by chip stacking for an increased miniaturization potential. Miniaturisation will soon also result in interconnect dimensions that surpass the mean free path (MFP) in Cu, the commonly used material for interconnects today, with a sharp increase in resistivity as a result. By changing the through silicon via (TSV) interconnect material from Cu to a carbon nanotube (CNT)/Cu composite, continued scaling can be ensured both in terms of electrical conductivity, ampacity and signal delays. Furthermore, a reduced skin effect can be achieved ensuring lower signal losses at higher RF frequencies making the CNT/Cu composite an ideal candidate to replace tranditional Cu interconnects. In this paper, we are demonstrating a coplanar waveguide (CPW) test structure using CNT/Cu filled TSVs connected to Au transmission lines on SiO2-passivated high resistivity Si substrates. The parasitic losses of the CNT/Cu TSV based CPW test structure were measured using a Sparameters test setup. The results showed that the CNT/Cu TSVs with affiliated contacts increased the signal losses up to S21 = -5.5 dB compared to Au reference transmission lines. These results are in line with previous results using CNT based TSVs and will serve as a basis for future improvements of CNT based interconnect technology for 3D integration.

Carbon nanotube/copper composite through silicon vias

3D integration

RF measurement

Author

Andreas Nylander

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Marlene Bonmann

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

Andrei Vorobiev

Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory

Josef Hansson

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Nan Wang

SHT Smart High-Tech

Yifeng Fu

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

Johan Liu

Chalmers, Microtechnology and Nanoscience (MC2), Electronics Material and Systems Laboratory

2019 IEEE 14th Nanotechnology Materials and Devices Conference, NMDC 2019

9084012

14th IEEE Nanotechnology Materials and Devices Conference, NMDC 2019
Stockholm, Sweden,

Subject Categories

Materials Engineering

Nano Technology

DOI

10.1109/NMDC47361.2019.9084012

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