Fabrication and electrical characterization of thick-metal-film coplanar waveguides on silicon oxide films by directly bonding Al foils
Year: 2025
Type: article
Abstract: We directly bonded 17 μm thick Al foils to 2 μm SiO2 films on Si substrates with a resistivity of 1–10 Ω cm by using the surface activated bonding and fabricated coplanar waveguides (CPWs) as a prototype of bonding-based interconnects on interlayer dielectrics on low-resistivity substrates. Their RF characteristics were compared with the characteristics of CPWs made of evaporated 0.8 μm thick Al layers on the SiO2 films and those of CPWs directly fabricated on the exposed surfaces of underlying Si substrates. The Al-foil based CPWs on the SiO2 films revealed the smallest attenuation constant, which implied that their conductor and/or substrate losses were lower than those of the other CPWs. This result indicates that the direct bonding of metal foils to dielectric films is promising for realizing low-loss interconnects monolithically integrated on low-resistivity substrates.
Authors: Saki Murotani, Sakura Uehara, Jianbo Liang, Eiji Shikoh, Yoshihisa Kaneko, Naoteru Shigekawa
Institutions: Osaka Metropolitan University, Osaka City University
Language: English
Topic: 3D IC and TSV technologies
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,210
OpenAlex ID: W4409875006