Low temperature Au-Au surface-activated bonding using nitrogen atmospheric-pressure plasma treatment for optical microsystems

摘要

This study investigated the effect of nitrogen (N) atmospheric-pressure (AP) plasma treatment on the Au-Au bonding property. Surface analysis using x-ray photoelectron spectroscopy (XPS) before and after AP plasma treatment with different gases: N and Ar+O was performed. In the case of Ar+O AP plasma treatment, the oxidation of the Au surface (AuO) was detected by the chemical shift of the 4f levels in XPS spectra. In contrast, no oxidation of Au surfaces was observed after N AP plasma treatment. N AP plasma treatment was effective in improving the bondability between Au/Au compared with Ar+O AP plasma treatment (bonding temperature: 150°C).