Process method for etching and cleaning oxide film in deep groove before epitaxial growth

Abstract

The invention discloses a process method for etching and cleaning an oxide film in a deep groove before epitaxial growth. The method comprises the following steps: (1) etching the deep groove; (2) forming a sacrificial oxide film in the deep groove by virtue of thermal oxidation; (3) removing the sacrificial oxide film in the deep groove by using diluted hydrofluoric acid or hydrogen fluoride steam; (4) cleaning by using SPM, APM and HPM and drying by using isopropyl alcohol; and (5) carrying out epitaxial growth. The method can be used for achieving the purposes of completely removing the oxide film, fully cleaning and drying and successfully finishing the follow-up epitaxial growth.

Description

technical field [0001] The invention belongs to the field of semiconductor integrated circuit manufacturing, in particular to an oxide film etching and cleaning process method in a deep trench before epitaxial growth. Background technique [0002] The use of deep trenches is ubiquitous in the fabrication of semiconductor devices. In some devices, deep trenches with a depth of more than 30 microns are also used. During the etching process of the deep trench, some damage will inevitably be introduced to the side and bottom, which will affect the quality of the subsequent epitaxial growth. The general practice is to use thermal oxidation to grow a sacrificial oxide layer to repair the damaged silicon surface before growing epitaxy, then use wet process to etch the oxide film and subsequent cleaning, and finally carry out epitaxial growth. Because the depth of the groove is too deep, the aspect ratio is relatively large, and the surface tension of the general BOE (buffered oxi...

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Problems solved by technology

Because the depth of the groove is too deep, the aspect ratio is relatively large, and the surface tension of the general BOE (buffered oxide film etchant) is relatively large, resulting in relatively poor wetting ability, so it is difficult to contact the bottom of the groove, resulting in oxidation. Insufficient removal of the film may easily lead to failure of subsequent epitaxial growth, resulting in failure to generate epitaxial layers in the lower part of the deep trench, see figure 1

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