Method for reducing the damage to a substrate surface in ONO etching

Abstract

The invention provides a method reducing the damage to a substrate surface in ONO etching. The method comprises following steps; the first step, of depositing on a substrate successively a first oxide layer, a nitride layer and a second oxide layer to form an ONO structure on the substrate; the second step, of processing the ONO structure by the method of lithography and dry etching to expose the substrate surface; the third step, perform thermal oxidation treatment on the semiconductor structure after the second step to form a thermal oxidation layer on the surface of the semiconductor structure; the fourth step, of removing the thermal oxidation layer by a wet etching process.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, more specifically, the invention relates to a method for reducing substrate surface damage in ONO etching. Background technique [0002] The ONO (Oxide-Nitride-Oxide, Oxide / Nitride / Oxide) structure is a structure that is often encountered in the manufacturing process of semiconductor devices. Moreover, ONO structures often need to be deposited and etched during semiconductor device fabrication. [0003] figure 1 and figure 2 The ONO etching steps according to the prior art are schematically shown. Such as figure 1 and figure 2 As shown, firstly, a first oxide layer 21 , a nitride layer 22 and a second oxide layer 23 are successively deposited on a substrate 10 (generally a silicon substrate) to form an ONO structure on the substrate 10 . The ONO structure is subsequently etched, thereby exposing part of the substrate surface 11 . [0004] However, the existing problem is that i...

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Problems solved by technology

[0004] However, the existing problem is that if the first oxide layer 21 at the bottom of the ONO structure is too thin, the exposed part of the substrate surface 11 is likely to be damaged due to excessive dry etching

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