  We present a comparative study of the manufacture of binary pupil masks for
coronagraphic observations of exoplanets. A checkerboard mask design, a type of
binary pupil mask design, was adopted, and identical patterns of the same size
were used for all the masks in order that we could compare the differences
resulting from the different manufacturing methods. The masks on substrates had
aluminum checkerboard patterns with thicknesses of 0.1/0.2/0.4/0.8/1.6$\mu$m
constructed on substrates of BK7 glass, silicon, and germanium using
photolithography and chemical processes. Free-standing masks made of copper and
nickel with thicknesses of 2/5/10/20$\mu$m were also realized using
photolithography and chemical processes, which included careful release from
the substrate used as an intermediate step in the manufacture. Coronagraphic
experiments using a visible laser were carried out for all the masks on BK7
glass substrate and the free-standing masks. The average contrasts were
8.4$\times10^{-8}$, 1.2$\times10^{-7}$, and 1.2$\times10^{-7}$ for the masks on
BK7 substrates, the free-standing copper masks, and the free-standing nickel
masks, respectively. No significant correlation was concluded between the
contrast and the mask properties. The high contrast masks have the potential to
cover the needs of coronagraphs for both ground-based and space-borne
telescopes over a wide wavelength range. Especially, their application to the
infrared space telescope, SPICA, is appropriate.
