  Metalenses built up by artificial sub-wavelength nanostructures have shown
the capability of realizing light focusing with miniature lens size. To date,
most of the reported metalenses were patterned using electron beam lithography
(EBL), which requires long processing time and is not suitable for mass
production. Here, we demonstrate an amorphous silicon (a-Si) metalens on a
12-inch glass wafer via the 193 nm ArF deep UV immersion lithography, with
critical dimension (CD) as small as 100 nm. The layer transfer technology is
developed to solve the glass wafer handling issue in complementary
metal-oxide-semiconductor (CMOS) fabrication line. The measured numerical
aperture (NA) is 0.494 with a beam spot size of 1.26 {\mu}m, which agrees well
with the simulation results. The focusing efficiency of 29.2% is observed at
the designed wavelength of 940 nm. In addition, the metalens is applied in an
imaging system, which further verifies its focusing functionality.
