High-resolution laser recording on metal and oxide films
摘要
The paper presents the studies results of the nonlinear photothermal effect in the process of direct laser recording on films of molybdenum and a number of oxides: MoO3, TiO2, ZrO2 and bilayer Cr/ZrO2. Research has shown that the impact of focused laser radiation with threshold values of power density leads to the formation of tracks and nanodots with a characteristic size multiple smaller than the effective spot diameter (which determines the basic resolution of the lithographic setup). It is shown that with sufficiently sharp beam focusing, super-diffraction track resolution is easily achievable during laser processing. Thus, under the action of continuous laser radiation with a wavelength of 532 nm and an effective spot diameter of 800 nm on molybdenum films, ablation tracks with a minimum width of 220 nm were obtained. It is shown that changing the effective spot diameter does not affect the relative magnitude of the effect. The best result was achieved in the nanosecond laser exposure mode, in which a 6-fold reduction in the element size (nanodot) on the bilayer Cr/ZrO2 was observed. The possibility of manufacturing diffraction gratings with a meander relief on ZrO2 films is shown where the period of which is equal to or less than the effective beam diameter.