New Layer Transfer Technology Moves Processed Circuits to the Best Substrates for the Application
Posted date : May 11, 2007

Transferring a layer with all the circuits from a processed wafer onto another support substrate decouples the exigencies of circuit fabrication from the needs of the final application.

The best substrate for circuit fabrication is not always the best choice for the functioning of the chip. Nor is the best substrate for the final application necessarily one that is well suited to high-volume manufacturing.

To decouple circuit fabrication and application needs, TraciT Technologies (now part of the Soitec Group’s services offering) has developed a generic process to transfer thin layers of processed wafers onto different supports.

TraciT Technologies’ circuit layer transfer offers new solutions to wafer level packaging issues. Finished integrated circuits can be moved onto various supports such as silicon, fused silica, silicon carbide or pre-processed wafers, by simple or double transfer. The ability to transfer finished circuits onto new supports is a promising way to improve device performance or to enable hetero-structure stacking for 3D-integration.

Optimize for the application

The ability to move a finished circuit onto another support without jeopardizing yield opens new doors for designers of chips for RF applications, image sensors, hetero-structure integration and advanced 3D structures. The target support need only be suited to the final application; it is not limited by the exigencies of chip manufacturing.

Backside access

New structures with backside access to the active layer can be achieved thanks to TraciT’s circuit layer transfer technology. The image sensor field is a good example, wherein “backside illumination” can drastically increase quantum efficiency and simplify circuit design, resulting in significantly higher-sensitivity image sensors.

A high-yield process

While the TraciT process is applicable to circuits built either on bulk on or SOI, the result is particularly efficient for circuits built on SOI, as the insulator can be used as an etch-stop layer.

Circuit layer transfer is mature and robust for high-volume; yield is excellent. TraciT is currently ramping up a dedicated manufacturing line with new facilities and clean room.

In addition to circuit layer transfer, TraciT offers other services and technologies, including patterned SOI and customized substrates.

These circuits were first fabricated on SOI wafers, then transferred using TraciT’s technology onto fused silica wafers shown here. (Photo credit: Soitec / Christian Morel)

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