US Patent 10297510 Sidewall image transfer process for multiple gate width patterning

A method for fabricating a multiple gate width structure for an integrated circuit is described. A fin on a semiconductor substrate with a first hard mask layer is covered by a first and second sacrificial gate each of which includes a second hard mask layer. Spacer layers and a dielectric layer are formed over the first and second sacrificial gate structures. The resulting structure is planarized so that the first and second sacrificial gate structures and the dielectric layer have coplanar top surfaces. The first and second sacrificial gate structures are removed to respectively form first and second trench recesses in the dielectric layer. The trench recesses are filled with a conductor to form permanent gate structures. A first permanent gate structure is formed in the first trench recess has a first length and a second permanent gate structure is formed in the second trench recess has a second length greater than the first length.