Pulsed Laser-Induced Reactive Processing of CVD-Diamond Substrates Under Liquid Ambient: A Process for 3-D Multi-Chip Modules

摘要

Drilling of diamond substrates, using pulsed Nd-YAG laser in water environment showed time efficient processing (about 28 times faster than in an air environment). In addition, better hole uniformity was observed in water environment than in an air environment. In water, the hot laser plasma on the substrate surface generates a reactive oxygen and/or hydrogen environment that increases drilling speed and makes it more uniform size hole. Diamond substrate drilling process with a pulsed Nd-YAG laser in an air environment generates significant audio noise and shock waves that can generate cracks at the processing boundary and break the thin diamond substrate during processing. The liquid environment reduces audio noise and dampens the shock wave. Therefore, laser drilling in a liquid medium is a useful method for drilling brittle materials such as diamond. After the shaping of the diamond substrate in the liquid medium, gold was successfully deposited on diamond substrates using an argon ion laser by changing the liquid medium from deionized water to the gold precursor solution.