Photolithography uses light to transfer a geometric pattern from a photomask to light-sensitive photoresist on the substrate.
MJB4 Mask Aligner is a contact lithography, which means there is no focus lens or large gap between photomask and substrate. The resolution of features which can be made by MJB4 depends on the wavelength of UV light and the gap distance between mask and substrate.
The UV source for MJB4 is 350 W mercury arc lamp, which typically has 365 nm and 405 nm peaks.
The contact modes include
Soft Contact: Push the wafer against the mask using mechanical force. The resolution is around 2 um.
Hard Contact: Push the wafer against the mask using N2 gas. The resolution is 1 um.