Electronics Integration and Reliability

EILB group is located in Micronova (www.micronova.fi) and uses the cutting-edge infrastructure of OtaNano, providing centralized access to advanced nanofabrication, nanomicroscopy and low-noise measurement facilities. In addition, the group has its own reliability testing laboratory including equipment for environmental, mechanical and thermomechanical testing, and uses different modeling tools to anticipate and rationalize reliability performance of heterogeneous integration in micro- and nanosystems.

The intensive co-operation of EILB with numerous semiconductor, electronics and MEMS manufacturing companies facilitates the comprehensive training of our students to combine scientific knowledge with industry-relevant technological advancement.

Examples of our recent research from large international Public-Private-Partnership projects are ENIAC Lab4MEMS II, ECSEL Informed and ECSEL POSITION II.

ENIAC Lab4MEMS II, Micro-Optical MEMS, micro-mirrors and pico-projectors: One of the main objectives of this project was to develop a fully integrated process for wafer level MEMS packaging utilizing Poly-Si through silicon via (TSV) capped MEMS devices. Sc. “vias before bonding” capping process and contact metallizations for Poly-Si TSVs (see Fig. below) were developed together with VTT and industrial partners (Okmetic and Murata Finland). Then the process integration was demonstrated by using piezoelectrically driven MEMS actuators.

Figure 1a) and 1b). SEM micrographs of the fully integrated MEMS package including Al redistribution layer, Cap wafer poly-Si TSVs, and wafer level SLID bonding providing electrical interconnection between the device and cap wafer as indicated by the SEM-EDS elemental analysis

ECSEL InForMed, An Integrated Pilot Line for Micro-Fabricated Medical Devices: The project covered development, assembly and fabrication of smart catheters and other minimally invasive diagnostic and therapeutic instruments and tools. The focus of the research in EILB was in development of advanced bonded silicon-on-insulator (SOI) structures for flexible sensor assemblies.

ECSEL POSITION II Towards the next generation of smart catheters and implants: Miniaturized MEMS sensors and transducers using advanced materials are studied in this project to realize smart catheters. EILB group studies the structural stability of different piezo-films, alternative piezo/electrode material stacks and Piezoelectric Micromachined Ultrasonic Transducers (PMUT) devices.

Recent doctoral dissertations from the EILB group include “Solid-liquid interdiffusion bonding for MEMS device integration” by A. Rautiainen https://aaltodoc.aalto.fi/handle/123456789/34427 and “Quality, Microstructural Refinement and Stability of Atomic-layer-deposited Aluminum Nitride and Aluminum Oxide Films” by M. Broas https://aaltodoc.aalto.fi/handle/123456789/33794.

Our teaching is part of the major Translational Engineering of AEE program, and includes e.g. the following courses:

• ELEC-E8712 Design for Reliability
• ELEC-E8713 Materials and Microsystems Integration
• ELEC-E8714 Sustainable Electronics
• ELEC-E8711 Materials Compatibility

For more information, please contact prof. Mervi Paulasto-Kröckel ([email protected]), senior lecturer, Dr. Vesa Vuorinen ([email protected]) or doctoral candidate Mr. Glenn Ross ([email protected]).