The 2017 edition of the annual International Wafer Level Packaging Conference in San Jose, CA, has recognized the work of Dr. Wolfram Steller with not one, but two Best Paper Awards: The “Best of Conference Paper” and “Best of 3D Track Paper” awards were won with his talk on “Dual Side Chip Cooling Realized by Microfluidic Interposer Processing on 300mm Wafer Diameter”. Dr. Steller’s presentation of the technical implementation of a 3D chip stack with the two-sided cooling of high-performance processors convinced the audience of the great promise of the proposed process technologies.

The technologies presented by the authors were developed as part of the EU “CarrICool” project in partnership with other European contributors. IBM defined a high performance processor stack as a possible application, which led the project partners to lay out a 3D stack for dual side chip cooling with attention to the expected system performance and feasibility of the technical processes. The silicon components were produced at Fraunhofer IZM - ASSID and assembled at IZM. Particular emphasis was laid on the design of a fluid interposer that can accommodate electric signaling on the horizontal plain and liquid cooling on the vertical. The resulting design demonstrated the feasibility of liquid cooling of processors with around 700W of thermal emission on 4cm2 at a maximum chip temperature of 85°C.