Sequential Plasma Activation for Low Temperature Bonding of Aluminosilicate Glass

Low temperature bonding of glass materials is a focus of research and development for the fabrication and packaging of optical and microfluidic devices. In order to bond glass materials with post-bonding annealing at no more than 200 °C, surface activation by plasma treatment is effective by forming OH groups on the bonding surfaces. In this study, sequential plasma activation using O 2 plasma, N 2 plasma, and N radicals are investigated for components of aluminosilicate glass. The substrates of fused silica, sapphire, and aluminosilicate glass are successfully bonded by sequential plasma activation and post-bonding annealing at 200 °C. Compared to conventional plasma activation bonding using only O 2 plasma, the bond strength is improved for fused silica and aluminosilicate glass, but not for sapphire. XPS analysis reveals that the sequential plasma activation including N 2 plasma leads to aluminum nitrides formation in case of sapphire and aluminosilicate glass bonding, which results in a lower bond strength than fused silica. It has been demonstrated that sequential plasma activation is effective for the bonding of SiO 2 by introducing unstable and reactive silicon oxynitrides at the bonding interface.