Chemically amplified soft-x-ray resists : sensitivity, resolution, and molecular photodesorption

The sensitivity, ion photodesorption, and lithographic performance of selected novolac-based chemically amplified resists have been studied at an exposure wavelength of 140 Å. Flood exposures of the resits AZ PF514, AZ PN114, and SAL 601 yield D(0.9) values of 2.5-3.5 mJ/cm(2) for 0.25-µm-thick films. Contrast values range from 3 for AZ PN114 to 5 for SAL 601. Photodesorption of fragment ions induced by 140-Å radiation has been examined in AZ PN114 by using time-of-flight mass spectrometry and compared with poly(methylmethacrylate) (PMMA). Mass-integrated ion desorption yields from AZ PN114 are found to be ∼ 90 times less per exposure than from PMMA. Soft-x-ray projection imaging in AZ PF514 and SAL 601 has been characterized by use of a multilayer-coated 20 × Schwarzschild objective and a transmissive Ge/Si mask illuminated by a laser plasma source.