lithography X-ray lithography PXL CHMO:0001442 XL A synthesis technique which uses X-rays to transfer a pattern to a substrate. The substrate is coated with a film (or 'resist) and a beam of X-rays is scanned across a patterned mask. The mask consists of an X-ray absorber (e.g. Au) on a membrane that is transparent to X-rays (e.g. SiC). The X-rays induce chemical reactions in the resist and the desired pattern is obtained by selectively removing either exposed or non-exposed regions of the resist ('developing'). proximity X-ray lithography