Method for forming metal silicide

Abstract

The invention provides a method for forming metal silicide. Before a metal silicide block layer is formed, a layer of silicofluoride glass film is deposited on a silicon substrate to be as a buffer layer. Fluorine element in the silicofluoride glass film can spread into the silicon substrate. Introduction of the fluorine element can restrain the metal from suddenly entering the silicon substrate together in an initial stage when the metal silicide is formed, and can fix the metal element which has already spread into the silicon substrate, thereby reducing defects.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for forming a metal silicide. Background technique [0002] With the rapid development of VLSI, the integration of devices is getting higher and higher, and the size is getting smaller and smaller. When the size of the device is reduced to the sub-micron level, many problems will arise accordingly, such as the metal oxide semiconductor field effect (MOS) transistor, due to the reduced size, it will cause the gate electrode and the source / drain region of the MOS transistor to be damaged. Surface resistance and contact resistance increase, causing signal delay in MOS transistors. [0003] In order to solve the problems caused by reducing the size of the device, the metal silicide process is generally used to deposit refractory metals titanium (Ti), cobalt (Co), Nickel (Ni), etc., form metal silicide through an annealing process, but there are also som...

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Problems solved by technology

[0005] During the formation of metal silicide, attention should also be paid to the influence of the oxide layer on the silicon surface. If there is an oxide layer on the silicon surface, the formation quality of the metal silicide will be poor, resulting in increased device resistance and increased leakage current.

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