Motohiro Yasui

Machining of micro-through-holes on glass plate by femtosecond laser pulses

Lime-glass and silica-glass plates with thickness of 100 μm were drilled with a ultra-short pulse laser(780nm, 150fs pulses at 1kHz). The surface of the glass plate at front side and rear side were observed by SEM, and the transmitted laser power though the glass plate was measured for both of glass. The appearance of the drilled hole of lime-glass was compared with that of silica-glass. The drilling characteristics of lime-glass and silica-glass plates with thickness of 100 μm by femto-second laser pulse were studied. On rear side, the crack occurred before drilling through the plate. The crack on the rear side occurred in lime-glass at smaller shot number than in silica-glass. The transmitted laser power ratio was decreased with increasing laser intensity. Interesting phenomenon that the lower glass plate began to be drilled before the upper glass plate was drilled through, when two glass plates with air gap of 12 μm were drilled.