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Due to the rapid spread of mobile handheld devices, industrial demands for micro-scale holes with a diameter of even smaller than 100μm in sapphire/silicon wafers have been increasing. Holes in sapphire wafers are for heat dissipation from LEDs; and those in silicon wafers for interlayer communication in three-dimensional integrated circuit (IC). We have developed a sapphire wafer driller equipped with a 532nm laser in which a cooling chuck is employed to minimize local heat accumulation in wafer. Through the optimization of process parameters (pulse energy,repetition rate, number of pulses), quality holes with a diameter of 30μm and a depth of 100μm can be drilled at a rate of 30holes/sec. We also have developed a silicon wafer driller equipped with a 355nm laser. It is able to drill quality through-holes of 15μm in diameter and 150μm in depth at a rate of 100holes/sec.