Method for etching silicide-blocked oxide layer

Abstract

The invention provides a method for etching a silicide-blocked oxide layer. The method includes the steps that in predetermined technological conditions, partial etching is performed on the silicide-blocked oxide layer through dry etching; further etching is performed on the silicide-blocked oxide layer through wet etching so as to form patterns of the silicide-blocked oxide layer. The predetermined technological conditions are that etching power is 150W-250W, pressure is 50mT-100mT, and etching time is not less than 10 seconds.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, and more specifically, the invention relates to an etching method for a silicide blocking oxide layer. Background technique [0002] The salicide block layer (SAB) is used to protect the surface of the silicon wafer. Under its protection, the silicon wafer does not form undesired metal silicides with other metals such as Ti and Co. [0003] In some processes, an oxide layer is used as a silicide barrier. [0004] The oxide layer that acts as a silicide barrier layer (referred to herein as the "silicide barrier oxide layer") needs to be etched to form the silicide barrier oxide layer pattern; thus, the silicide barrier oxide remaining after etching No metal silicide will be formed on the surface of the silicon wafer below the layer; however, metal silicide will be formed on the surface of the silicon wafer where the silicide blocking oxide layer is removed after etching. [0005] Initi...

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Problems solved by technology

[0007] However, in the prior art, when dry etching is used to partially etch the silicide blocking oxide layer, for the silicide blocking oxide layer with a total thickness of 300-400 Å, it is often not well controlled to silicidate. The etch speed and etch uniformity of dry etching when the object blocking oxide layer is partially etched, and the thickness of the partially etched silicide blocking oxide layer is often too thin to control the remaining silicide well Barrier oxide layer thickness and uniformity

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