Abstract: In an etching method for fabricating a semiconductor device, at first, a semiconductor substrate including a contact region is provided. Then, a metallic nitride layer is formed on the semiconductor substrate to prevent over-etching. Thereafter, a dielectric layer is formed on the metallic nitride layer. Then, an etching process is performed to form an opening passing through the metallic nitride layer and the dielectric layer to expose the contact region. The etching method may further include forming a diffusion barrier layer between the metallic nitride layer and the semiconductor substrate to prevent diffusion of a material of the contact region.