Method for forming semiconductor memory device capable of preventing the silicidation of capacitor bottom electrode caused by silicon plasma treatment of TiN diffusion barrier

摘要

PURPOSE: A method for manufacturing a semiconductor memory device is provided to prevent silicidation of a lower electrode, by using silicon-containing gas to perform a plasma treatment regarding a TiN diffusion barrier layer so that the TiN diffusion barrier layer is changed to a Ti-Si-N layer, by performing a cleaning process by a mixed solution of NH4OH and H2O and by eliminating a remaining silicon layer on the Ti-Si-N layer. CONSTITUTION: An interlayer dielectric(35) covering a semiconductor substrate(30) having a completed transistor is selectively etched to form a contact hole exposing a source/drain junction region(34) of the transistor. A TiN diffusion barrier layer is formed on the resultant structure including the contact hole. A plasma process is performed regarding the TiN diffusion barrier layer by using silicon-containing source gas so that at least a part of the TiN diffusion barrier layer is changed to a Ti-Si-N layer. A wet-cleaning process is performed to eliminate a remaining silicon layer on the Ti-Si-N layer. A capacitor composed of a lower electrode(38), a dielectric layer(39) and an upper electrode(40) is formed on the Ti-Si-N layer.