Ah. Fisher et al., PATTERN PLACEMENT ERRORS IN MASK MEMBRANES, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 15(6), 1997, pp. 2249-2254
X-ray and ion-beam lithographic processes require the use of advanced
masks with free-standing thin membranes. In the fabrication of these m
asks, the pattern transfer process involves the deposition or removal
of a thin layer of material (or portions of a layer), which can produc
e relatively large pattern placement errors. The stress-induced distor
tions of both x-ray and stencil mask membranes (due to the individual
fabrication processes) have been simulated by finite-element procedure
s. For patterned areas of both mask membrane types, equivalent models
with uniform characteristics have also been developed and assessed for
validity. These models facilitate the calculation of global in-plane
distortions needed to perform pattern specific emulation. (C) 1997 Ame
rican Vacuum Society.