Techniques Used for Mask Less Lithography

The ability to do selective lithography drives the semiconductor technology, but with the ever decreasing minimum feature size the need for higher resolution increases and so does the cost and complexity. Mask less lithography provides solution in the form of several techniques which are cost effective. In scanning electron beam lithography, instead of light, electron beam is used and the setup and principle used are similar to that of scanning electron microscope. Similarly scanning probe lithography is based on atomic force microscopy which employs cantilevered tips to modify the surface at an atomic scale. Both these techniques have low throughput and need to bring in some parallelism to improve the throughput. Zone-plate array lithography (ZPAL) uses diffracted light for patterning the surface. There are several other techniques as well. Though ZPAL has an increased speed, but all the techniques are being improved to achieve higher throughput rates.