US Patent 7749913 Semiconductor device manufacturing method

A first silicon containing film, an organic material film, a second silicon containing film are formed. The second silicon containing film is patterned to have a narrow width pattern and a wide width pattern. The organic material film is patterned to have a narrow width pattern and a wide width pattern. A side wall is formed on a side surface of the second silicon containing film and the organic material film by coating with a third silicon containing film. The narrow width pattern of the second silicon containing film is removed by using a mask that covers the second silicon containing film patterned to have a wide width pattern and the side wall. Finally, the organic material film is removed.