US Patent 10522414 Method and structure for FinFET isolation

A method of forming a semiconductor device includes receiving a substrate having a fin extending from the substrate, first and second dummy gate stacks over the substrate and engaging the fin; removing the first and second dummy gate stacks thereby forming a first trench and a second trench, wherein the first and second trenches expose first and second portions of the fin respectively; removing the first portion of the fin; and forming a gate stack in the second trench, the gate stack engaging the second portion of the fin.