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http://dx.doi.org/10.5369/JSST.2006.15.1.058

Thermocompression bonding for wafer level hermetic packaging of RF-MEMS devices  

Park, Gil-Soo (Department of Materials Science and Engineering, Korea University)
Seo, Sang-Won (Department of Electrical Engineering, Korea University)
Choi, Woo-Beom (B&P Science)
Kim, Jin-Sang (Korea Institute of Science and Technology)
Nahm, Sahn (Department of Materials Science and Engineering, Korea University)
Lee, Jong-Heun (Department of Materials Science and Engineering, Korea University)
Ju, Byeong-Kwon (Department of Electrical Engineering, Korea University)
Publication Information
Journal of Sensor Science and Technology / v.15, no.1, 2006 , pp. 58-64 More about this Journal
Abstract
In this study, we describe a low-temperature wafer-level thermocompression bonding using electroplated gold seal line and bonding pads by electroplating method for RF-MEMS devices. Silicon wafers, electroplated with gold (Au), were completely bonded at $320^{\circ}C$ for 30 min at a pressure of 2.5 MPa. The through-hole interconnection between the packaged devices and external terminal did not need metal filling process and was made by gold films deposited on the sidewall of the throughhole. This process was low-cost and short in duration. Helium leak rate, which is measured to evaluate the reliability of bonded wafers, was $2.7{\pm}0.614{\times}10^{-10}Pam^{3}/s$. The insertion loss of the CPW packaged was $-0.069{\sim}-0.085\;dB$. The difference of the insertion loss between the unpackaged and packaged CPW was less than -0.03. These values show very good RF characteristics of the packaging. Therefore, gold thermocompression bonding can be applied to high quality hermetic wafer level packaging of RF-MEMS devices.
Keywords
wafer-level packaging; thermocompression bonding; hermetic packaging;
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