  3D integrated circuit (3D-IC) technology gained acceptance due to the ability
to achieve extremely high level of integration, where hundreds of ICs are
stacked vertically. Such level of integration can result in local power
dissipation of more than 50 kW/cm2. This will lead to instant evaporation of
the IC, unless an effective cooling technique is employed. Liquid cooling may
be one of the most effective techniques for this task. To investigate the
effectiveness of this technique, we designed, built and tested a testing
platform. The platform includes a testing chip and a cooling module. The test
chip contains heaters to provide the power and sensors to measure the local
temperature. The study shows that the proposed cooling modules can reduce the
temperature for a 420W/inch square circuits to a normal operating range of ICs
of 39-50 degrees centigrade, using 2 phase R22 liquid coolant.
