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2009
Conference Paper
Titel
Thermo compression bonding with gold interfaces
Abstract
Thermocompression bonding of gold is an interesting technology for achieving wafer level bonding at low temperature without the application of an electric field (anodic bonding) or complicated pre-bond cleaning procedure (plasma assisted silicon direct bonding). To understand the influence of the different bonding parameters the underlying bonding mechanism has been investigated. Different bonding conditions have been evaluated. The parameters that have been varied are temperature, bonding pressure and time. To characterize the bond quality the bond toughness of the specimens were tested using shear strength measurements. For showing the possibility to create simultaneously electrical and mechanical contacts for 3D integration of MEMS, also the electric conductivity of the contacts have been evaluated. The results show clearly that higher bonding pressure leads to higher yield. Experiments with different bonding time have not shown a repeatable, significant influence. This is in line with the results of other groups. The detailed influence of bonding temperature could not be shown yet. However current results indicate that a higher temperature leads to higher bonding strength because it propagates diffusion at the interface.