Editing Photoresist (section)

===Electron-beam exposure===
Photoresists can also be exposed by electron beams, producing the same results as exposure by light. The main difference is that while photons are absorbed, depositing all their energy at once, electrons deposit their energy gradually, and scatter within the photoresist during this process. As with high-energy wavelengths, many transitions are excited by electron beams, and heating and outgassing are still a concern. The dissociation energy for a C-C bond is 3.6 eV. Secondary electrons generated by primary ionizing radiation have energies sufficient to dissociate this bond, causing scission. In addition, the low-energy electrons have a longer photoresist interaction time due to their lower speed; essentially the electron has to be at rest with respect to the molecule in order to react most strongly via dissociative electron attachment, where the electron comes to rest at the molecule, depositing all its kinetic energy.<ref>{{cite journal |year=2006 |title=IR photon enhanced dissociative electron attachment to SF6: Dependence on photon, vibrational, and electron energy |journal=Chemical Physics |volume=329 |issue=1–3 |pages=148 |bibcode=2006CP....329..148B |last1=Braun |first1=M |last2=Gruber |first2=F |last3=Ruf |first3=M. -W |last4=Kumar |first4=S. V. K |last5=Illenberger |first5=E |last6=Hotop |first6=H |doi=10.1016/j.chemphys.2006.07.005}}</ref> The resulting scission breaks the original polymer into segments of lower molecular weight, which are more readily dissolved in a solvent, or else releases other chemical species (acids) which catalyze further scission reactions (see the discussion on chemically amplified resists below). It is not common to select photoresists for electron-beam exposure. Electron beam lithography usually relies on resists dedicated specifically to electron-beam exposure.