SOI Wafers

SOI (silicon-on-insulator) is a semiconductor technology which enables a full isolation of each electronic component on an integrated circuit by using a buried oxide layer. The heart of a SOI wafer is an ultra-thin, monocrystalline, conductive layer on a silicon wafer. All electronic operations take place, on this isolated layer, enabling higher switching frequencies and lower power consumption all the while avoiding unwanted heat production. SOI chips have been used recently in consumer goods and applications, such as computing, gaming, automotive, networking and imaging, as well as generally in devices requiring ultra low power consumption.

In semiconductor processing, efficient cleaning and particle removal prior to critical process steps enables maximum yield. Wafer Bonding is a process which is strongly affected by particles: each particle on the wafer surface produces a void significantly larger than its diameter, contributing to a dramatic yield loss.

The EV Group cleaning station enables the effective removal of particles, low chemicals consumption and quick spin drying without back splash. Each single wafer cleaning station can be configured, besides standard DI-water rinse, with following options: megasonic nozzle, area transducer, brush and diluted chemicals for single-side cleaning.

The megasonic cleaning nozzle is based on water molecules energized by high frequency vibrations. The water molecules hit the wafer surface and the result is a very efficient removal of particles having submicron dimensions. The DI-water flow prevents particles reattaching to the wafer surface.

The area transducer provides megasonic energy to a rotating substrate surface with patented radial uniformity. All portions of the substrate receive the same amount of megasonic dosage with no transducer scanning or moving parts. Transducer and substrate are coupled with a thin layer of cleaning fluid.

Brush cleaning is another method of pre-conditioning the wafer surface for bonding. Brush and wafer rotation speed are fully programmable, as are brush pressure and media flow.

Please see our related products EVG®301 and EVG®320 for detailed information.


IR image of bonded wafer pair showing particle generated voids. Source EVG.

IR image of bonded wafer pair showing no voids. Source EVG.