A method for forming a sacrificial oxide layer on a silicon wafer

Abstract

The invention discloses a method for a silicon wafer to form a sacrificial oxide layer. The method of the invention comprises steps of performing first annealing processing on a cleaned silicon wafer, performing second annealing processing on the silicon wafer after first annealing processing to form an oxygen silicon layer structure, performing thermal oxidation processing on an oxygen silicon layer structure to form a sacrifice oxide layer structure to obtain the silicon wafer having the sacrifice oxide layer. The method of the invention reduces flaws and foreign matter density on the surface of the silicon wafer through performing first annealing on the silicon wafer and reduces the thickness of the sacrifice oxide layer; an oxide silicon layer is formed through performing second annealing processing on the wafer after the first annealing processing; and the oxide silicon layer improves thickness uniformity of the sacrifice oxide layer and shortens the technology time of the sacrifice oxide layer. As a result, the surface which is formed through thermal oxidation treatment is good in flatness. The method of the invention improves reliability and yield of members and reduces manufacture cost of the device.

Description

technical field [0001] The invention belongs to the technical field of semiconductor chip manufacturing technology, and in particular relates to a method for forming a sacrificial oxide layer on a silicon wafer. Background technique [0002] Ion implantation and high temperature drive-in processes are used in the fabrication of silicon devices. Both ion implantation and high temperature process will damage the silicon surface, affect the surface morphology, and form a damaged layer. The surface damage layer will directly affect the electrical performance and reliability of the device. In order to improve the surface morphology of silicon after ion implantation and high-temperature drive-in, reduce surface defects, and improve device performance, surface treatment of silicon is required. [0003] There are two commonly used surface treatment methods at present: the first is to use dry etching to remove the damaged layer on the silicon surface. The advantage of this method i...

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Problems solved by technology

[0004] Currently commonly used oxidation conditions, in order to completely remove the surface damage layer, a thicker sacrificial oxide layer needs to be grown, resulting in a longer process time and increasing the manufacturing cost of the device, usually relying on wet cleaning to reduce the impurity density, which cannot reduce the surface defect density , the uniformity of the formed sacrificial oxide layer is not good, and the thickness fluctuation is also large

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