High-quality gate oxide forming method

Abstract

The invention provides a high-quality gate oxide forming method. The method comprises the following steps that a wafer already undergoing shallow trench isolation is provided; the wafer is placed in an iCoNi reaction chamber to remove a native silicon oxide layer on the silicon face; (NH4)2SiF6 will be formed on the wafer surface during a SiCoNi etching reaction process; in a normal temperature condition, the (NH4)2SiF6 layer will not be removed in the SiCoNi reaction chamber; instead, the (NH4)2SiF6 layer will be kept as a protective layer on the wafer surface to prevent silicon exposure and native oxide regeneration; then the wafer is placed in an oxidation furnace; after the wafer enters the oxidation furnace, the (NH4)2SiF6 protective layer will be decomposed and volatilized when the temperature of the oxidation furnace rises; and if the highest technical temperature of the oxidation furnace continuously rises to satisfy the temperature and technical condition required for gate oxide growing, then the gate oxide starts to grow. By means of the technical solution, the native silicon oxide can be prevented from being formed on the wafer surface again before the gate oxide is formed. The gate oxide quality is improved. Product performance improvement can be further facilitated.

Description

Technical field [0001] The invention relates to the field of semiconductor devices and processing and manufacturing, in particular to gate oxide layer formation technology and SiCoN dry etching process in the field of semiconductor integrated circuit manufacturing; more specifically, to a method for forming a high-quality gate oxide layer. Background technique [0002] The formation of gate oxide layer is a very critical technology in integrated circuit manufacturing, which directly affects the electrical performance and reliability of the device. At present, this layer of gate silicon oxide is mainly formed by thermal oxidation. Below 32nm, HK materials have been used as gate oxides, such as hafnium oxide. Before the gate oxide layer is grown, the surface of the wafer is cleaned to remove the native silicon oxide layer on the surface or the silicon oxide layer (pad oxide layer or native silicon oxide layer) remaining from the previous process. The quality of this layer of nati...

AI Technical Summary

Problems solved by technology

[0016] However, no matter whether the silicon oxide before the gate oxide growth is removed by the wet method or the SiCoNi process, there is a difficult problem to solve, that is, during the period between the removal of this layer of silicon oxide and the growth of the gate oxide layer, The native oxide layer will still grow

At present, the thickness of the native silicon oxide layer can only be controlled by strictly controlling the queuing time (Q-time) to reduce its impact

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