Nanotech Prototypes with E-beam Nanolithography

By Earl Boysen, Nancy C. Muir, Desiree Dudley, Christine Peterson

E-beam nanolithography is used in nanotechnology laboratories to create prototypes of integrated circuits and other semiconductors. It is like ultraviolet-based lithography in that a beam of electrons is focused on the photoresist. However, there are some significant differences between the two methods.

For example, electric fields are used instead of a lens to focus the beam. Also, rather than using a mask to define a pattern on the photoresist, the beam moves to create the pattern. The entire operation takes place in a vacuum because air or any other substance blocks the movement of electrons.

You can buy expensive e-beam nanolithography systems (for a few million) or modify the scanning electron microscope (SEM) you have in your lab to draw patterns in the resist. Both dedicated systems and retrofitted systems are versatile in producing any pattern a researcher can think of.

A pattern created using e-beam nanolithography. [Credit: Courtesy of Sungbae Lee at Rice University]
Credit: Courtesy of Sungbae Lee at Rice University
A pattern created using e-beam nanolithography.

Systems designed from scratch specifically for nanolithography can write features as small as 10 nm wide. This capability makes these systems ideal for producing nanoscale patterns in a lab producing prototypes. However, because the e-beam systems have to scan the pattern onto a wafer, rather than stepping a pattern from a prepared mask, they are too slow for high-volume integrated circuit manufacturing.