A Thin-Film Heat Flux Sensor Fabricated on Copper for Heat Transfer Measurements in Parallel Channel Heat Sinks

A combination of lithography-based microfabrication and micro end milling is used to manufacture thin-film resistance temperature detector (RTD) heat flux sensors on bulk copper substrates. The fabrication process uses photoresist patterning, metal deposition, and lift-off to build the sensor and micro-end milling to segment the sensors. Micro end milling tests were performed to establish determine the optimum conditions for sensor removal which minimized delamination and burr formation. It was determined that starting on the backside (opposite the sensor) of the copper wafer and machining through to the thin film layers resulted in the least amount of burr formation