Micro-Machining Characteristics of Ceramics by Harmonics of Nd:YAG laser

抄録

Aluminum nitride and silicon carbide are expected as a useful material for the substrate in semiconductor industry because of their excellent properties. Precision micro-machining without crack and with little heat affected zone is required for their applications. Shorter wavelength makes it possible to remove a material with little heat affected zone because of its high photon energy. Therefore, effects of wavelength on machining characteristics of AlN and SiC in micro-drilling using Q-swithched YAG harmonics were experimentally investigated. The drilled depth increased with decreasing the wavelength. Under the reduced pressure condition, the drilled depth increased, and the better surface integrity could be obtained compared to the atmospheric pressure condition. The circumference region around the drilled hole was oxidized for all the case, and the oxidization in the case of fourth harmonic was more remarkable than that in second harmonic. In the initial stage of drilling for AlN with fundamental wavelength, the irradiated point expanded by the absorption of laser beam with increasing the number of laser pulse, and the processing was carried out by crumbling the grain due to the thermal expansion. On the other hand, the higher harmonics could make a hole at the irradiated point from the initial stage without thermal expansion.