The formation of a chrome-less phase shifting mask includes preparing a
mask substrate with a chrome metal layer, forming main and complementary
pattern portions in the chrome metal layer, removing a remaining layer of
radiation sensitive material, forming a layer of radiation sensitive
material over the complementary pattern portion, etching the main pattern
portion of the mask substrate using the patterned chrome metal layer as
an etch mask, removing remaining portions of the chrome layer from the
main pattern portion and removing the layer of radiation sensitive
material over the complementary pattern portion. The fabrication of a
chrome-less phase shifting mask includes combining writing a phase layer
and a chrome layer into a single write step in a chrome-less phase
shifting mask fabrication process, wherein an overlay shift is prevented
between the phase layer and the chrome layer. A phase edge is not formed
between a juncture of a main pattern region and a scribe region of the
mask during fabrication of the mask