EVG’s new wafer bonding system is a fully automated tool for production-level fabrication of 450mm SOI wafers.
Transitioning to larger wafers heightens the need for process uniformity. Wafer bonding is no exception, as process parameters must be applied with a high degree of both precision and uniformity. This requirement will become particularly critical within the next couple of years, as adoption of silicon-on-insulator (SOI) substrates will intensify in tandem with the impending shift to 450 mm wafers. Wafer bonding is a crucial technique for SOI wafer fabrication, as it enables formation of high-quality, single-crystal silicon films on an insulating layer: the essence of an SOI substrate.
To ensure chipmakers’ access to these highly stringent wafer bonding capabilities, EV Group recently announced the semiconductor industry’s first bonding system for the fabrication of 450 mm SOI wafers. Dubbed the EVG850SOI/450 mm, the new system will support and facilitate the industry transition to 450 mm wafers from the current 300 mm standard. Leading SOI wafer provider Soitec will qualify and develop processes on the EVG850SOI/450mm after its installation in spring, 2012.
SOI is expected to play an enabling role in the migration to 450 mm, because it not only addresses most of the associated scaling challenges, but it also delivers better power/performance for sub-22-nm CMOS and 3D IC technologies compared to similar-geometry bulk CMOS.
Fully automated production tool
The new EVG850SOI/450 mm wafer bonding system leverages EVG’s strengths in wafer bonding technology – and SOI bonding, specifically – to create a fully automated tool for production-level fabrication of SOI wafers. It consists of two process modules: a cleaning module for cleaning and pre-conditioning of wafers before wafer bonding, and an SOI pre-bonding module. In the pre-bonding module, the two silicon wafers are joined together either in a vacuum or in an atmospheric chamber. The tool is equipped with state-of-the-art 450 mm load ports and front opening unified pods (FOUPs).
The first tool in EVG’s 450 mm arsenal, the new bonder will serve as the key starting point for the production of 450 mm SOI wafers, and can be utilized for the development of other EV Group 450 mm products, such as mask aligners and coating systems. An extension of the system with additional modules is planned as a further step to increase wafer throughput.
As most of the required metrology tools are not ready for 450 mm wafers yet, the system will allow for processing of 300 mm and 450 mm wafers and parts of the evaluation program can be performed on 300 mm wafers. While one size doesn’t fit all, the new EVG wafer-bonding system can fit 300 mm and 450 mm of advanced SOI wafers, helping ensure a smooth transition to the 450 mm generation.