Process Simulation deals with modeling the fabrication steps of semiconductor devices such as transistors and focuses on front end of line manufacturing steps. Back end of line steps are handled with tools like Fammos TX. Powerful numerical algorithms simulate process steps like implantation, diffusion and dopant activation, etching, deposition, oxidation, and epitaxial growth in different semiconductor materials. Process conditions like the ambient chemical composition, temperature, pressure, etc. during individual fabrication steps are typical inputs. The final output is a 2D or 3D device structure which can be used for device simulation. Synopsys has four process simulation tools: Sentaurus Process; Taurus TSUPREM-4; Sentaurus Lithography; and Sentaurus Topography.