Eutectic bonding, also called eutectic soldering, is where the combination of two or more metals allow direct transformation from solid to liquid state or vice versa at specific temperature without passing two-phase equilibrium. The eutectic temperature is much lower than the melting temperature of the materials that are involved in the bonding process. Eutectic bonding is ideal for high-vacuum applications as this process has very low outgassing.
Eutectic wafer bonding is widely used in the MEMS industry for hermetic sealing, pressure or vacuum encapsulation as it allows highly reliable wafer-level processing for devices with the smallest form factors. The most common metals/alloys that are used in eutectic bonding are Al-Ge, Au-Sn and Au-In. However, there are many other material combinations available that can produce a eutectic bonding system. Additionally, the ability of silicon to alloy with metals like Au can also be the basis for eutectic bonding. All eutectic bonds must go through a liquid phase and thus are less sensitive to surface flatness irregularities, scratches and particles, thereby facilitating high volume manufacturing. Bonding temperature, time and pressure are the most important parameters for eutectic bonding where high bond strength can be achieved with low processing temperature and minimum resultant stress. Eutectic bonding can additionally enable hermetic sealing and electrical interconnections in a single process. Compared to other intermediate layers, such as adhesives or glass-frit, eutectic bonding also promotes better out-gassing and hermeticity.
Visit our booth #B1241 at SEMICON EUROPA 2025 & visit our poster presentation at the APC:
"High Throughput Digital Lithography Development for 3D Device Integration " held by Business Development Manager Dr. Ksenija Varga.
Visit EVG's booth at The International Conference on Wafer Bonding and listen to our talks:
"Impact of Surface Condition on In-Plane Distortion in Si Wafer Bonding: Correlation with Adhesion Energy and Bondwave Propagation Speed" by Technology Development Dr. Christoph Flötgen.
“Advanced IR Laser Debonding on Silicon Wafers for RDL- first FOWLP” by Supervisor Process Technology Peter Urban.
“D2W Bonding of III-V and piezo electrical materials for Heterogeneous Integration” by Team Leader Process Technology Mariana Pires.
“Comprehensive Bond strength optimization of LiTaO3 bonding using ComBond Technology” by Supervisor Process Technology Michael Dornetshumer.
“ComBond Bonding of Diamond and other Materials for Advanced Thermal Management” by Senior Process Technology Engineer Matthias Danner.
and visit the Poster Presentation, where we present following topic:
“Comparative Analysis of Atmospheric and ComBond-Activated TiTi thermos-compression Bonding” by Team Leader Process Technology Thomas Stöttinger.
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