X-RAY MASKS WITH TUNGSTEN ABSORBERS FOR USE IN THE LIGA PROCESS

X-ray masks with tungsten absorbers have been made for the LIGA proces s by sputter deposition of tungsten and subtractive patterning through reactive ion etching with CF4 and SF6. Sputtering was optimised in or der to minimise stress and the anisotropy of stress in tungsten layers . Absorbers with critical dimensions as small as 0.5 mum and thickness es of 2.5 mum have been achieved. With tungsten absorbers, 2.2 mum in thickness, templates for electroplating, more than 20 mum in thickness , have been fabricated from PMMA.