Development of on-chip vacuum generation by gas–liquid phase transition

In this paper, we developed on-chip vacuum generation technique using gas–liquid phase transition. Fabricated quartz chip was composed simply of a structural vacuum chamber and a diaphragm for pressure measurement by laser displacement meter. Efficient reduction of pressure in the chamber was accomplished by the phase transition with the simple design of the fabricated chip. The pressure was reduced by decreasing the temperature of low boiling point liquid filled into the chamber after closing its valve. The lowest pressure attained to 50.8 kPa (diethyl ether) or 23.2 kPa (water) at 7 min from atmospheric pressure by using diethyl ether and water, respectively. The highest performance of micro vacuum pump was achieved. The absolute pressure below 25 kPa was maintained about 20 min due to low leakage of the fabricated chip.