As already stated in the introduction optical lithography
continues to be the mainstream technology for the semiconductor industry
because of its high wafer throughput. From the late 1960s, when ICs
had linewidths of roughly 10 m, to 1998, when minimum linewidths
have reached 0.2
m, optical lithography has been used
ubiquitously for manufacturing. This situation will be continued for the next
generation with a linewidth of 0.15
m. Beyond this point, at
0.1
m and
below, proximity 1x X-ray is the most likely alternative,
but there are also great efforts to extend optical methods like
extreme ultraviolet (EUV) towards the 100 nm-regime.
Below 100 nm minimum feature size particle
beam lithography techniques like electron-beam and ion-beam are
considered [3].