the lithographic tools are classi,ed in two families:
“parallel writing” (or replication)methods (e.g., optical lithography)
and “sequential writing” (or patterning) methods (e.g.,
focused-electron beam lithography).
In parallel writing, the whole pattern is made simultaneously
using a mask, which dictates the features to be reproduced.
It is easy to understand that sequential lithography is
slower as the pattern is written point by point on the resist
surface and is therefore more expensive.