A new breed of high volume wafer processing equipment - In Situ Aligned Wafer Bonding Systems

摘要

Aligned wafer bonding equipment and technology plays a key role in enabling high-volume manufacturing of MEMS devices and is also an important factor with emerging technology such as 3D integrated circuit fabrication. Though wafer bonding techniques have been used for decades for fabricating silicon-on-insulator (SOI) wafers and other areas of microelectronics research and manufacturing; these early commercial drivers of wafer bonding technology primarily focused on well controlled environmental and physical conditions during the bond cycle such as vacuum, temperature, pressure and inert gases to be encapsulated in between die on the wafers. Bond alignment was always a secondary criterion with typical requirements in the 10um to 100um+ range. With the advent of 3D Integration as a potential enabler for the continuation of Moore's law, the aligned wafer bonding requirements have shifted significantly. The primary focus has become post-bond alignment accuracy over large area wafers (200 and 300mm). Requirements have increased by approximately an order of magnitude into the range of 0.5um-1.5um. The following paper provides a summary of wafer to wafer alignment approaches in use today and describes a new generation of "In-Situ Aligned Wafer Bonding Equipment" that utilizes advanced sub-resolution IR localization and distortion alignment techniques to achieve submicron post-bond alignment accuracy.