Plasma-activated direct bonding of patterned silicon-on-insulator wafers to diamond-coated wafers under vacuum

Can, Uryan Isik
Bayram, Barış
Direct wafer bonding requires the surfaces to have low surface roughness (R-a < 0.5 nm) as well as to be free of any particles or contaminants. Meeting these requirements for wafers patterned with lithography and dry etching presents a serious problem in terms of removal of photoresist residue and etch-related particles, which would require expensive additional equipment to be removed. In this study, we propose the use of chemical mechanical polishing (CMP) to be performed after all lithography and dry etch process steps involving several masks are completed. To reduce the adverse effect of any remaining slurry that might reside in the etched structures, we also propose to reduce the maximum annealing temperature from 550 degrees C down to 300 degrees C. The effect of lower annealing temperature on bonding is compensated using a sequential plasma activation with 60 s of O-2 followed by 90 s of N-2 on contacting surfaces made of silicon dioxide to achieve successful wafer bonding. Initial plasma activation with O-2 additionally serves as a final cleaning step whereas the following activation with N-2 for an extended duration is to fully activate the surface for direct bonding. This proposed technique can motivate the use of direct wafer bonding for microfabrication of advanced MEMS devices.


Residual stress and Young's modulus measurement of capacitive micromachined ultrasonic transducer membranes
Yaralioglu, GG; Ergun, AS; Bayram, Barış; Marentis, T; Khuri-Yakub, BT (2001-01-01)
Membranes supported by posts are used as vibrating elements of capacitive micromachined ultrasonic transducers (CMUTs). The residual stress built up during the fabrication process determines the transducer properties such as resonance frequency, collapse voltage, and gap distance. Hence, it is important to evaluate and control the stress in thin film CMUT membranes. The residual stress in the membrane causes significant vertical displacements at the center of the membrane. The stress bends the membrane post...
Spherical harmonic-based random fields based on real particle 3D data: Improved numerical algorithm and quantitative comparison to real particles
Liu, X.; Garboczi, E. J.; Grigoriu, M.; Lu, Y.; Erdoğan, Sinan Turhan (2011-02-15)
The shape of particles often plays an important role in how they are used and in the properties of composite systems in which they are incorporated. When building models of systems that include real particles, it is often of interest to generate new, virtual particles whose 3D shape statistics are based on the 3D shape statistics of a collection of real particles. A previous paper showed mathematically how this can be carried out, but only had a small set of real particle shape data to use and only made a l...
Thermal contact conductance of nominaly flat surfaces
Yüncü, Hafit (2006-11-01)
The variation of thermal conductance of contact has been investigated as a function of apparent contact pressure experimentally. Experimental data has been obtained for steel, brass, copper and aluminum test pieces having different surface roughness over a wide range of contact pressures. Experimental results are compared with the theoretical predictions of an existing theory. Comparison revealed good agreement of trend with the experimental data, however, numerical values vary widely. Theory can predict th...
Polycarbonate based zeolite 4a filled mixed matrix membranes: preparation, characterization and gas separation performances
Şen, Değer; Yılmaz, Levent; Department of Chemical Engineering (2008)
Developing new membrane morphologies and modifying the existing membrane materials are required to obtain membranes with improved gas separation performances. The incorporation of zeolites and low molecular-weight additives (LMWA) into polymers are investigated as alternatives to modify the permselective properties of polymer membranes. In this study, these two alternatives were applied together to improve the separation performance of a polymeric membrane. The polycarbonate (PC) chain characteristics was a...
Calculation and measurement of electromechanical coupling coefficient of capacitive micromachined ultrasonic transducers
Yaralioglu, GG; Ergun, AS; Bayram, Barış; Haeggstrom, E; Khuri-Yakub, BT (2003-04-01)
The electromechanical coupling coefficient is an important figure of merit of ultrasonic transducers. The transducer bandwidth is determined by the electromechanical coupling efficiency. The coupling coefficient is, by definition, the ratio of delivered mechanical energy to the stored total energy in the transducer. In this paper, we present the calculation and measurement of coupling coefficient for capacitive micromachined ultrasonic transducers (CMUTs). The finite element method (FEM) is used for our cal...
Citation Formats
U. I. Can and B. Bayram, “Plasma-activated direct bonding of patterned silicon-on-insulator wafers to diamond-coated wafers under vacuum,” DIAMOND AND RELATED MATERIALS, pp. 53–57, 2014, Accessed: 00, 2020. [Online]. Available: