Although SEH's thick bonding and polishing process produces wafers that are suitable for many semiconductor and MEMS applications, the limits of the polishing technology created a need for another process that could produce even thinner layers with even tighter layer thickness uniformity. SEH also offers a thin SOI Unibond® wafer manufactured with the SmartCut® process, which is licensed from Soitec.
In the thin bonding process, the active and handle wafers are bonded as in the thick bonding process, but the active wafer includes a hydrogen implanted layer. After bonding, the SOI wafer is annealed at moderate temperatures after which the bulk of the active layer separates from the bonded portion at the limit of the hydrogen implant. (See Figure 1.) Minimal additional processing is required to produce the final SOI wafer.
The SOI wafers produced by this process have very thin active layers with exceptional layer thickness uniformity. Thickness of 1000 nm and below are possible with a uniformity of <±5%. These wafers are of the highest quality with HF and Secco defect concentrations that are suitable for the most demanding semiconductor applications.
SEH's Unibond® process is now available for 200 mm and 300 mm wafers. Our new facility in Yokonodaira, Japan has adequate capacity to meet the needs of the semiconductor industry for the foreseeable future.
SOI Product Brochure
SOI for MEMS applications