An indium tin oxide (ITO) layer on a lime glass substrate for flat panel displays has been patterned without a mask by scanning Nd:YLF (neodymium-doped yttrium-lithium-fluoride) laser irradiation in a pulsed mode. Both fundamental and frequency doubled lines of 1.047 μm and 523.5 nm were compared for processing. SEM (scanning electron microscopy) and surface stylus observation revealed that only the top ITO layer could be removed without substrate etching. A finer patterning was possible for irradiation of a 523.5 nm line because of the better focusing feature, though higher laser energy density was required for this line than for a 1.047 μm line because of the lower light absorption.

No abstract

No abstract

The ion-beam sensitivity of polymer resists, mainly PMMA, was investigated for argon, gallium, helium, and hydrogen ions. The resists were exposed in a standard ion accelerator at energies of 40 to 120 keV. The samples were irradiated with doses varying between 5×1010 and 5×1014 cm−2. It was found that the resists are about a factor of 100 more sensitive for hydrogen ions than for electrons of 20 keV; whereas for helium, up to a factor of 150, and for argon and gallium a factor of more than 300 were found for positive resists. Using an energy of 120 keV, layers of more than 1.3 μm thickness can be exposed by hydrogen ions, 1.0 μm thickness by helium ions and 0.25 μm thickness by argon ions. The effective sensitivity is energy-dependent, and within the region of 40 to 120 keV between a factor of 1.4 and 2.0, with the higher sensitivity at lower energies. The achievable resolution of structures using ion beams is very high. Resists with a sensitivity of 5×10−7 C/cm2 easily yield a resolution of 0.25 μm wide and 1.3 μm thick lines.

No abstract