Overview of recent direct wafer bonding advances and applications

H Moriceau, F Rieutord, F Fournel, Y Le Tiec, L Di Cioccio, C Morales, A M Charvet and C Deguet

Abstract

Direct wafer bonding processes are being increasingly used to achieve innovative stacking structures. Many of them have already been implemented in industrial applications. This article looks at direct bonding mechanisms, processes developed recently and trends. Homogeneous and heterogeneous bonded structures have been successfully achieved with various materials. Active, insulating or conductive materials have been widely investigated. This article gives an overview of Si and SiO₂ direct wafer bonding processes and mechanisms, silicon-on-insulator type bonding, diverse material stacking and the transfer of devices. Direct bonding clearly enables the emergence and development of new applications, such as for microelectronics, microtechnologies, sensors, MEMs, optical devices, biotechnologies and 3D integration