In this thesis, analytical, CFD and some experimental studies of microchannel heat sink (MHS) were performed. This thesis develops a closed-loop single-phase microchannel cooling system using de- ionized water as a coolant fluid for high heat flux integrated circuits. The design, fabrication and closed-loop system using MHS, pump, filter and heat exchanger is summarized. A Ni-Cr wire heat source is fabricated as a heater. A copper heat exchanger is designed to dissipate heat from the heated fluid coming out of the MHS. Some experiments were performed in the fabrication of microchannels on a...