Insulating tube, semiconductor device employing the tube, and method of manufacturing the same

摘要

An insulating tube includes a underlying insulating film, a first sidewall insulating film disposed on the underlying insulating film, a second sidewall insulating film disposed on the underlying insulating film, opposite to the first sidewall insulating film so as to provide a cavity between the first and second sidewall insulating films having the same height as the first sidewall insulating film, and an upper insulating film provided over the first and second sidewall insulating films.