English (EN) Services Contact Menu Metal Diffusion Bonding EV Group Technologies Metal Diffusion Bonding Metal Diffusion Bonding Metal diffusion bonding for precise interfaces and alignment Introduction Features Figures Introduction Metal diffusion bonding, also known as Thermo compression bonding (TCB), is a direct solid-state diffusion bonding process and is based on atomic contact. In this bonding technique, two metals are brought into contact by applying heat and force simultaneously after which the atoms diffuse to form the bond interface. TCB is widely used in the production of RF MEMS, light emitting diodes (LEDs), laser diodes as well as power devices. TCB provides hermetic sealing of packaged internal structures and electrical interconnects in a single process step. Because of their high diffusion rates, Au, Al and Cu are the most established materials that are used in TCB. Compared to Al and Cu, Au requires less temperature for diffusion and has an added advantage of not becoming oxidized. The diffusion rate depends on the chosen temperature and applied pressure where the atoms diffuse between crystal lattices. Here, grain boundary and bulk diffusion takes place in addition to standard surface diffusion. In this technology, wafer-level bonding is achieved at low temperatures without the application of an electric field. Nevertheless, good control of CTE (coefficient of thermal expansion) and synchronized wafer expansion is important to prevent any resulting stress and alignment shift during bonding. Furthermore, the applied force and its uniformity are important, which also depend on the metal density (features) and size of the wafers. In TCB, the bonding temperature and the applied pressure are inversely proportional, which gives a feasibility to tailor the bonding parameters. Features Electrically conductive High fracture toughness Small bonding frames Hermetic sealing Very good post-bond alignment No contamination No or very little deformation Figures SEM cross-section image of 3-axis accelerometer bonded by TCB. Cross-section image of 3D silicon vertical interconnects in a wafer stack bonded by TCB (Cu-Cu). Events SEMICON Europa 2021 MESSE MÜNCHEN | Co-located with Productronica 16.11. - 19.11.2021 Munich, Germany SEMICON Japan 2021 Venue: Tokyo Big Sight/Online 15.12. - 17.12.2021 Tokyo, Japan Show all events Related downloads EVG Solutions for MEMS Brochure - 2.28 MB EVG GEMINI® Series Brochure - 2.12 MB EVG® 500 Series Brochure - 1.83 MB EVG Solutions for R&D Brochure - 1.66 MB Talk to our EVG technology experts! Questions? Contact form Related products EVG®501 Wafer Bonding System EVG®510 Wafer Bonding System EVG®520 IS Wafer Bonding System EVG®540 Automated Wafer Bonding System EVG®560 Automated Wafer Bonding System GEMINI® Automated Production Wafer Bonding System ComBond® Automated High-Vacuum Wafer Bonding System Questions about our technologies? Contact the EVG experts Send us a message Related News From wafers to power electronic applications: new consortium to create European supply chain for silicon carbide semiconductors Oct, 2021 EV Group Celebrates “40+1 Year” Anniversary with Exciting Live Event at Corporate Headquarters Sep, 2021 Applied Materials Introduces New Technologies and Capabilities for Accelerating the Semiconductor Industry's Heterogeneous Integration Roadmap Sep, 2021 EV Group Products Technologies Company Careers Social Media LinkedIn Facebook Twitter YouTube Join our newsletter We will send you updates on new products and technologies. Your Email Subscribe © 2021, EV Group (EVG) Imprint Privacy Policy Terms of use