Semiconductor integrated circuit device and its manufacturing method

The object of the present invention is to prevent the transverse etching of a silicide film of a connection part between a bit line and a polycrystalline silicon plug by preventing the unevenness of a polycrystalline silicon plug in a bit line connection hole. To achieve the object, a bit line BL, formed simultaneously with a first layer wiring 18, is made of a laminated film of a Ti film 18a, a titanium nitride film 18b and a tungsten film 18c, and a titanium silicide film 20 containing N or O is formed in a connection part between the bit line BL and a plug 19. A titanium silicide film 20 containing N or O may be also formed in a connection part between the first layer wiring 18 and a semiconductor board 1. A tungsten silicide layer containing N or O, a cobalt silicide layer containing N or O or a cobalt silicide layer may be formed in place of the titanium silicide film 20.