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.
Meet EVG at booth #3131 at SEMICON China 2024!
Listen to our Talk "Unlocking New Possibilities: Nanoimprint Lithography for AR/VR/XR Waveguide Fabrication" held by Senior Process Technology Engineer Schuster Patrick on March, 29 at the eXtended Reality Korea.
Visit us at our booth at the CS / PIC and PE International Conference and listen to our talks:
"Heterogenous Integration of Compound Semiconductors by W2W and D2W Bonding" held by Business Development Manager Anton Alexeev at the CS Conference.
"Advances in PIC Manufacturing for Sensing and Datacom Applications – All Thanks to Nanoimprint Lithography" held by Business Development Manager Thomas Achleitner at the PIC Conference.
"Cost-effective SiC substrate manufacturing for power devices enabled by oxide-free wafer bonding" held by Business Development Manager Bernd Dielacher at the PE Conference.
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