Gold-tin eutectic bonding for hermetic packaging of MEMS devices with vertical feedthroughs

Torunbalci, Mustafa Mert
Demir, Eyup Can
Donmez, Inci
Alper, Said Emre
Akın, Tayfun
This paper presents a new method for wafer-level hermetic encapsulation of MEMS devices using low-temperature (280 to 300°C) Au-Sn eutectic bonding applied to the recently developed advanced MEMS (A-MEMS) process of the METU-MEMS Research Center, which uses an SOI cap wafer with vertical feedthroughs that does not need any complex via-refill or trench-refill process steps. The Au-Sn eutectic bonding process is achieved at 300°C with a bond pressure of 2 MPa by using a sealing alloy thickness less than 1.5 μm. The package pressure is characterized to be around 250 mTorr, without any getter activation. The remelting temperature of the Au-Sn bonding interface is measured by using differential scanning calorimetry (DSC) analysis and found to be around 280°C, verifying that the bonding is achieved at the desired eutectic composition (80% Au and 20% Sn), also confirmed by the energy dispersive X-ray spectroscopy (EDS) analysis. The shear strengths of several packages are measured to be above 20 MPa, indicating a mechanically-strong bonding. The robustness of the packages is also tested by subjecting them to high temperature storage at 200°C for 24 hours, and no degradation is observed in the hermeticity of the packages at the end of this period.


Torunbalci, M. M.; Alper, S. E.; Akın, Tayfun (2015-06-25)
This paper presents a novel, inherently simple and low-cost fabrication and hermetic packaging method developed for SOI-MEMS devices, where an SOI wafer is used for the fabrication of MEMS structures as well as vertical feedthroughs, while a glass cap wafer is used for hermetic encapsulation and routing metallization. Glass-to-silicon anodically bonded seals yield a very stable cavity pressure of 150 mTorr after 15 days. The shear strength of the fabricated packages is above 7 MPa. Temperature cycling and u...
A Method of Fabricating Vacuum Packages with Vertical Feedthroughs in a Wafer Level Anodic Bonding Process
Torunbalci, Mustafa Mert; Alper, Said Emre; Akın, Tayfun (2014-09-10)
This paper presents a new method for wafer level vacuum packaging of MEMS devices using anodic bonding together with vertical feedthroughs formed on an SOI cap wafer, eliminating the need for any sealing material or any complex via-refill or trench-refill vertical feedthrough steps. The packaging yield is experimentally verified to be above 95%, and the cavity pressure is characterized to be as low as 1 mTorr with the help of a thin-film getter. The shear strength of several packages is measured to be above...
Wafer level hermetic encapsulation of MEMS inertial sensors using SOI cap wafers with vertical feedthroughs
Mert Torunbalci, Mustafa; Alper, Said Emre; Akın, Tayfun (2014-02-26)
This paper reports a new, inherently simple, and high-yield wafer-level hermetic encapsulation method developed for MEMS inertial sensors, enabling lead transfer using vertical feedthroughs that do not require any complex via-refill or trench-refill processes. The process requires only seven masks to complete both the sensor and cap wafers, whereas the combined yield for the sealing and lead transfer is experimentally verified to be above 90%. Hermetic encapsulation is achieved by Au-Si eutectic bonding, an...
Gold-assembled silica-coated cobalt nanoparticles as efficient magnetic separation units and surface-enhanced Raman scattering substrate
Yıldırım, Lütfiye Sezen; Volkan, Mürvet (The Scientific and Technological Research Council of Turkey, 2019-01-01)
Magnetic and optical bifunctional nanoparticles that combine easy separation, preconcentration, and efficient SERS capabilities have been fabricated with high sensitivity and reproducibility through a low-cost method. These gold nanoparticles attached on magnetic silica-coated cobalt nanospheres (Co@SiO2/AuNPs) display the advantage of strong resonance absorption due to gaps at nanoscale between neighboring metal nanoparticles bringing large field enhancements, known as "hot spots". The prepared particles c...
Sharif, Parisa; Oral, Ahmet; Çırpan, Ali; Department of Micro and Nanotechnology (2021-7-14)
This thesis presents a novel method for fabrication of OLEDs on a specific flexible PET substrate with graphene anodes, demonstrating low sheet resistance, high work function, and an extremely high luminance. Firstly, a single-layer graphene growth process with chemical vapor deposition (CVD) method is optimized. Flexible anodes are then fabricated by stacking 7-layers of graphene films and doped with nitric acid to reduce the sheet resistance. Modified few layer graphene anodes by 29 Ω/□ sheet resistance a...
Citation Formats
M. M. Torunbalci, E. C. Demir, I. Donmez, S. E. Alper, and T. Akın, “Gold-tin eutectic bonding for hermetic packaging of MEMS devices with vertical feedthroughs,” 2014, Accessed: 00, 2020. [Online]. Available: