Investigation of Loss Reduction in the MnM Interposer for Millimeter-Wave Applications

• Grant number: 25/08007-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Engineering - Electrical Engineering - Electrical Materials
• Principal Investigator: Gustavo Pamplona Rehder
• Grantee: Rafael Greco Bellodi
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In millimeter waves (mmW), several unlicensed bands are being used for point-to-point communication links with very high bandwidth. These multi-gigabit links will be crucial for the infrastructure of emerging RF, mmW, and THz applications aimed at the high-speed telecommunications market (future generations of mobile communications, 6G and beyond), 77 GHz/120 GHz automotive radars, imaging, and high-sensitivity radar sensors. In this context, the Microelectronics Laboratory of the Polytechnic School of the University of São Paulo (LME-EPUSP) has developed an interposer based on a revolutionary low-cost MnM (Metallic nanowires Membrane) substrate with an inherent slow-wave effect. This new technology is based on nanoporous dielectric membranes filled with metallic nanowires, obtained through simple fabrication processes-even at frequencies above 100 GHz, where the critical dimensions of circuits face limitations even in the most advanced commercial technologies (such as CMOS), making their design unfeasible. The 3D integration on the MnM interposer was entirely developed at LME-EPUSP, using conventional microelectronics processes and readily available, low-cost materials. The MnM interposer is a highly flexible, high-performance solution already demonstrated through through-silicon vias (TSVs) and passive mmW circuits. Aiming to improve this interposer, this project proposes the study of loss reduction in the MnM substrate through testing with variations in the fabrication parameters of the alumina membrane. (AU)