Method for preventing cavities from generating in deep groove insulation technology

Abstract

The invention provides a method for preventing cavities from generating in deep groove insulation technology, which comprises the following steps: forming an source region protective layer on a semiconductor substrate; etching the source region protective layer and the semiconductor substrate to form a deep groove; etching the source region protective layer and the semiconductor substrate to form a shallow groove communicated with the deep groove; adopting a high temperature oxidation technology on the edge of the deep groove and the edge of the shallow groove; carrying out etching by the wet method to remove the silicon oxide formed by the high temperature oxidation technology, and precipitating an insulating medium in the deep groove and the shallow groove; carrying out the chemical machinery grinding to flatten the surface of the shallow groove. The method of the invention enables the edges and corners of the grooves to be smooth, thereby avoiding large quantities of cavities in the groove and ensuring the insulating property of the groove.

Description

technical field [0001] The invention relates to the technical field of integrated circuit manufacturing technology, in particular to a method for preventing voids in deep trench insulation technology. Background technique [0002] In the process of semiconductor integrated circuits, the traditional isolation technology is self-aligned field oxidation isolation technology, that is, the active area is covered with a hard mask, the substrate silicon in the field area is exposed, and then the isolation area is oxidized by thermal oxidation. silicon. This method is simple, practical, and has a mature production process. The disadvantage is that a "bird's beak" area will be formed at the boundary of the active region. In practice, it is difficult to reduce the size of the "bird's beak" to less than 0.1 μm. Therefore, when the feature size of the microelectronics process is reduced to 0.25 μm, the field oxidation process is gradually replaced by the Shallow Trench Isolation Techno...

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Problems solved by technology

In the prior art, due to the stress matching problem between the polysilicon insulating material used in large quantities and the substrate silicon material, it is necessary to use an etching process to remove the polysilicon insulating material in the shallow trench, and then combine silicon oxide deposition and chemical mechanical polishing to complete the shallow trench. Trench structure manufacturing, in addition, because the trench etching is very easy to form sharp corners, the sharp corners will be first joined in the subsequent deposition process, resulting in a large number of voids in the trench, thereby reducing the insulation performance

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