We have investigated direct micromachining of quartz glass, using pulsed laser plasma soft x-rays (LPSXs) having a potential capability of nanomachining because the diffraction limit is ∼10nm. The LPSX’s were generated by irradiation of a Ta target with 532nm laser light from a conventional Q switched Nd:YAG laser at 700mJ∕pulse. In order to achieve a sufficient power density of LPSX’s beyond the ablation threshold, we developed an ellipsoidal mirror to obtain efficient focusing of LPSXs at around 10nm. It was found that quartz glass plates are smoothly ablated at 45nm∕shot using the focused and pulsed LPSX’s.

We have investigated a technique for micromachining inorganic transparent materials. In the technique, patterning and coloration are performed by the direct irradiation of materials with pulsed laser soft x rays and the patterned areas are ablated using ultraviolet laser light. The technique utilizes the high precision of the soft x rays and the high energy density of conventional laser light. For demonstration, we irradiated quartz plates with Ta laser plasma soft x rays. This results in generation of transient surface opaque layers that absorb more than 40% of the 266nm Nd:YAG laser light. Applying the technique, quartz plates are found to be ablated smoothly at 85nm∕shots.

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