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http://dx.doi.org/10.5781/KWJS.2012.30.3.224

Effect of BOE Wet Etching on Interfacial Characteristics of Cu-Cu Pattern Direct Bonds for 3D-IC Integrations  

Park, Jong-Myeong (School of Materials Science and Engineering, Andong National University)
Kim, Su-Hyeong (MSP Center, Seoul Technopark)
Kim, Sarah Eun-Kyung (Graduate School of NID Fusion Technology, Seoul National University of Science and Technology)
Park, Young-Bae (School of Materials Science and Engineering, Andong National University)
Publication Information
Journal of Welding and Joining / v.30, no.3, 2012 , pp. 26-31 More about this Journal
Abstract
Three-dimensional integrated circuit (3D IC) technology has become increasingly important due to the demand for high system performance and functionality. We have evaluated the effect of Buffered oxide etch (BOE) on the interfacial bonding strength of Cu-Cu pattern direct bonding. X-ray photoelectron spectroscopy (XPS) analysis of Cu surface revealed that Cu surface oxide layer was partially removed by BOE 2min. Two 8-inch Cu pattern wafers were bonded at $400^{\circ}C$ via the thermo-compression method. The interfacial adhesion energy of Cu-Cu bonding was quantitatively measured by the four-point bending method. After BOE 2min wet etching, the measured interfacial adhesion energies of pattern density for 0.06, 0.09, and 0.23 were $4.52J/m^2$, $5.06J/m^2$ and $3.42J/m^2$, respectively, which were lower than $5J/m^2$. Therefore, the effective removal of Cu surface oxide is critical to have reliable bonding quality of Cu pattern direct bonds.
Keywords
3D IC; Wet etching; Cu-Cu bonding; Interfacial adhesion energy; Pattern density;
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Times Cited By KSCI : 1  (Citation Analysis)
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