We report optical parallel nanolithography
using bowtie apertures with the help of the interferometricspatial-
phase-imaging (ISPI) technique. The ISPI system
can detect and control the distance between the bowtie
aperture, and photoresist with a resolution of sub-nanometer
level. It overcomes the difficulties brought by the
light divergence of bowtie apertures. Parallel nanolithography
with feature size of 22 ± 5 nm is achieved. This
technique combines high resolution, parallel throughput,
and low cost, which is promising for practical applications.