SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To reduce contact resistance by preventing reduction of a contact area between a plug and a barrier layer in a DRAM in which a bit line is formed on the plug composed of a polycrystalline silicon film via the barrier layer. SOLUTION: When a plug 21 composed of a polycrystalline silicon film is formed inside a contact hole 19 to which a bit line BL is connected, the upper surface of the plug 21 is recessed to a level lower than the upper end portion of the contact hole 19. A plug 22 composed of a laminated layer film of a TiN film 26 and a W film 27 is formed on the plug 21. Subsequently, a bit line BL having a thinner width than the diameter of the contact hole 19 is formed by patterning the W film deposited on the contact hole 19. At this time, the W film 27 constituting the plug 22 is also etched in the contact hole 19, but the TiN film 26 constituting the other part of the plug 22 is hardly etched.