Fabrication and Thermal Performance of Copper Pillars Modified Micro Heat Pipe (MHP)

With the excellent thermal conductivity and the compatibility to micro electromechanical systems technology, silicon is widely used in micro heat pipes (MHPs). Copper shows higher heat transfer capability and capillary traction than silicon. Copper pillars modified microgrooves were fabricated on the silicon wafer using electroforming technique in this paper. Water contact angle measurements and thermal behavior tests were employed to the fabricated microgrooves and MHPs. Under the input power of 4 W, how the working fluid flowed in the microgrooves and steam chamber was easily observed by digital camera. The experiments demonstrated the working fluid flowed via copper pillars instead of the silicon microgrooves due to the adhesive force between working fluid and copper pillars were larger than that between working fluid and silicon microgrooves. This work showed copper pillars had a better capillary traction than the silicon microgrooves, and could make the MHP work as a vapor chamber.