A method is described for reducing the space width of holes in a first
resist pattern and simultaneously removing unwanted holes to change the
pattern density in the resulting second pattern. This technique provides
holes with a uniform space width as small as 100 nm or less that is
independent of pattern density in the second pattern. A positive resist
is patterned to form holes with a first pattern density and first space
width. A water soluble negative resist is coated over the first resist
and selectively exposed to form a second patterned layer consisting of
water insoluble plugs in unwanted holes in the first pattern and a thin
water insoluble layer on the first resist pattern in unexposed portions.
The plugs may form dense and isolated hole arrays while the thin
insoluble layer reduces space width to the same extent in remaining holes
in the second pattern.