Understanding the Exposure Process in the Extreme Ultra Violet Lithography

Although being the optical lithography, the extreme ultraviolet (EUV) lithography with 13.5-nm wavelength is very different from the deep ultraviolet (DUV) lithography with 193-nm wavelength. Hence, the understanding of the complex detailed EUV mechanisms to cause a chemical reaction in chemically amplified resists (CARs) is required to develop EUV resists and exposure process. In this paper, for organic, metal-organic and metal-oxide resists, the electron-scattering model of exposure mechanisms needs to include the elastic and inelastic mean free paths. On top of that, Dill's parameters of DUV and EUV resisters from the photo-generated reaction are discussed to indicate the physical and chemical characteristics. For CAR and EUV resists, Dill B parameter is large than Dill A and B parameters.