  This study presents the development of large-area (18 $\times $ 18 $\times $
2 cm$^3$), high refractive index ($n \sim $1.05) hydrophobic silica aerogel
tiles for use as Cherenkov radiators. These transparent aerogel tiles will be
installed in a Cherenkov detector for the next-generation accelerator-based
particle physics experiment Belle II, to be performed at the High Energy
Accelerator Research Organization (KEK) in Japan. Cracking has been eliminated
from the prototype aerogel tiles by improving the supercritical carbon dioxide
(scCO$_2$) extraction procedure when drying the wet gel tiles. Finally, a
method of mass-producing aerogel tiles for the actual detector was established.
It was confirmed that the experimentally manufactured aerogel tiles meet the
required optical and hydrophobic characteristics and have a uniform tile
density.
