US Patent 7259064 Forming integrated circuit devices

Methods of forming integrated circuit devices are provided. A first mask layer is formed overlying a first portion of a semiconductor substrate. The first mask layer further overlies a second mask layer overlying a second portion of the semiconductor substrate. The first mask layer overlying the first portion of the semiconductor substrate is patterned to define areas for removal of one or more layers of material interposed between the semiconductor substrate and the first mask layer. Portions of the one or more layers of material exposed by the patterned first mask layer are removed to define elements of the integrated circuit device overlying the first portion of the semiconductor substrate.