Ion beam lithography

In ion-beam lithography, polymer resists are usually exposed to light ions - protons, helium ions. The use of heavier ions makes it possible to dope the substrate or create thin layers of new chemical compounds on it. The differences between electron and ion lithography are due to the larger mass of the ion compared to the mass of the electron and the fact that the ion is a multielectron system. A thin ion beam has weaker angular scattering in the target than an electron beam, so ion beam lithography has a higher resolution than electron beam lithography. The energy loss of the ion beam in polymer resists is about 100 times higher than the energy loss of the electron beam, so the sensitivity of the resists to the ion beam is also higher. This means that exposure of the resist to a thin ion beam is faster than exposure to an electron beam. The formation of defects of the type of Frenkel pairs “vacancy - interstitial atom” by an ion beam changes the solubility rate of dielectrics and metals in some solvents by about five times. This eliminates the need for a polymer resist, since the material layers themselves behave like inorganic resists. Ion beam lithography systems provide a resolution of about 10 nm.