Combined Surface Activated Bonding Technique for Low-Temperature Cu/Dielectric Hybrid Bonding

Cu/dielectric hybrid bonding at low temperatures of no more than 200 degrees C remains challenging because of the different features of Cu-Cu and dielectric-dielectric (such as SiO2-SiO2) bonding. This paper reports a combined surface activated bonding (SAB) technique for low-temperature Cu-Cu, SiO2-SiO2, and SiO2-SiNx bonding. This technique involves a combination of surface irradiation using a Si-containing Ar beam and prebonding attach-detach process prior to bonding in vacuum. Wafer bonding experiments were conducted at either room temperature or 200 degrees C. Results of bonding strength measurements, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS) observations, and X-ray photoelectron spectroscopy (XPS) analysis were reported and discussed to understand the present combined SAB technique. (C) 2016 The Electrochemical Society. All rights reserved.