Method for forming a silicon titanide layer on a doped polysilicon trench of a device

Abstract

A method for forming a titanium silicon oxide layer on a doped polysilicon trench of a device: depositing a pad oxide film, an undoped polysilicon layer and a silicon nitride layer on the device substrate in sequence; according to the patterned silicon nitride layer, sequentially The silicon nitride layer, the undoped polysilicon layer, the pad oxide film and the device substrate are etched to form doped polysilicon trenches; after depositing the silicon oxide layer in the doped polysilicon trench, the doped polysilicon pillars are deposited and etched to The pad oxide film is thermally oxidized in the doped polysilicon trench to oxidize the sidewall of the non-doped polysilicon layer to obtain an oxide film as a silicon oxide sidewall; after dry etching the oxide film on the doped polysilicon pillar, the The silicon nitride layer, the non-doped polysilicon layer, the pad oxide film and the oxide film on the doped polysilicon column on the doped polysilicon trench are etched, titanium Ti is deposited and rapid annealing is used to form a TiSi2 layer. The method ensures that the formed TiSi2 layer film is continuous and smoothes the surface during the subsequent fabrication process of the metal interconnection layer.

Description

technical field [0001] The invention relates to the manufacturing technology of semiconductor devices, in particular to a method for forming a titanium silicon (TiSi2) layer on the doped polysilicon trench of the device. Background technique [0002] With the development of semiconductor devices, such as the development of metal oxide semiconductor field effect transistors (MOSFETs), the conduction speed of semiconductor devices has become an important criterion for judging the quality of semiconductor devices. In the manufacture of semiconductor devices, the self-aligned titanium silicon method is introduced as a means of improving the conduction speed of devices with doped polysilicon trenches. The self-aligned titanium silicon method is to make a silicon oxide sidewall on the doped polysilicon trench of the device, and then deposit a TiSi2 layer, wherein the silicon oxide sidewall avoids the doped polysilicon in the doped polysilicon trench and the device Short circuit b...

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Problems solved by technology

[0019] from figure 2 It can be seen that cracks will appear when the doped polysilicon pillars 21 are deposited in step 204, and this crack will cause two problems in the subsequent manufacturing process: the first problem is that the crack will be formed in the subsequent manufacturing process Expand, so that silicon dioxide is deposited in the crack while forming the silicon oxide sidewall in step 206, and it is difficult to remove, resulting in discontinuity of the film when the TiSi2 layer is formed in step 207 (it cannot be formed on the silicon dioxide layer TiSi2 layer), resulting in higher contact resistance; another problem, because the doped polysilicon column 21 is higher than the surface of the device substrate 10, in the process of making the subsequent metal interconnection layer, it will cause large surface fluctuations, which needs to be carried out. Additional planarization process to avoid deformation of contact holes in the metal interconnect layer due to large surface relief during photolithography

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