  Despite the fact that the resolution of conventional contact/proximity
lithography can reach feature sizes down to ~0.5-0.6 micrometers, the accurate
control of the linewidth and uniformity becomes already very challenging for
gratings with periods in the range of 1-2 {\mu}m. This is particularly relevant
for the exposure of large areas and wafers thinner than 300{\mu}m. If the wafer
or mask surface is not fully flat due to any kind of defects, such as
bowing/warpage or remaining topography of the surface in case of overlay
exposures, noticeable linewidth variations or complete failure of lithography
step will occur. We utilized the newly developed Displacement Talbot
lithography to pattern gratings with equal lines and spaces and periods in the
range of 1.0 to 2.4 {\mu}m. The exposures in this lithography process do not
require contact between the mask and the wafer, which makes it essentially
insensitive to surface planarity and enables exposures with very high linewidth
uniformity on thin and even slightly deformed wafers. We demonstrated pattern
transfer of such exposures into Si substrates by reactive ion etching using the
Bosch process. An etching depth of 30 {\mu}m or more for the whole range of
periods was achieved, which corresponds to very high aspect ratios up to 60:1.
The application of the fabricated gratings in phase contrast x-ray imaging is
presented.
