Manufacturing method of super-junction device and super-junction device

Abstract

The invention relates to a manufacturing method of a super-junction device and the super-junction device. The method comprises the following steps: forming a graphical mask layer on an upper surface of an epitaxial layer of a first conductive type; etching the epitaxial layer of the first conductive type based on the graphical mask layer so as to form a trench in the epitaxial layer of the first conductive type; forming an epitaxial layer of a second conductive type in the trench and enabling the upper surface of the epitaxial layer to be lower than the upper surface of the graphical mask layer and higher than the upper surface of the epitaxial layer of the first conductive type; thermally oxidizing the upper surface of the epitaxial layer of the first conductive type and the upper surfaceof the epitaxial layer of the second conductive type below the graphical mask layer to form an oxide layer; and removing the graphical mask layer and the oxide layer. According to the invention, thecurvature of the upper surface of a trench junction is smaller, the upper surface of the super-junction device is flatter, and the production cost and the process complexity are reduced while the reliability of the device is improved.

Description

technical field [0001] The invention relates to the technical field of integrated circuit design and manufacture, in particular to a manufacturing method of a super junction device and a super junction device. Background technique [0002] Compared with the planar power semiconductor structure, the high-voltage super-junction semiconductor structure has many advantages such as high withstand voltage and low on-resistance, and is widely used in the preparation process of various semiconductor devices. [0003] At present, there are two mainstream semiconductor super-junction fabrication processes, one is to use multiple implantation and epitaxy technology; the other is to use trench etching and backfill technology. The technology of multiple implantation and epitaxy is relatively mature but expensive. However, the process of trench etching and backfill technology is relatively simple and low in cost, which is more conducive to improving the yield rate of the semiconductor man...

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Problems solved by technology

[0004] However, in the traditional process of preparing semiconductor super-junction structures using trench etching and backfilling techniques, it is necessary to use a chemical mechanical polishing process to planarize the epitaxial layer filled in the trenches, because the polishing fluid used in the chemical mechanical polishing process Due to the corrosion characteristics of the groove, the corrosion rate of the epitaxial layer near the groove is small, so that the epitaxial layer forms a sharp corner near the edge of the groove; when the oxide layer is formed by thermal oxidation process after removing the mask layer, there will be a large When a device is formed on such a substrate, the existence of a larger protrusion will cause a step difference in the subsequent gate oxide, polycrystalline, etc., which will affect the electrical performance of the device, causing the device to have a risk of leakage, and It affects the length and stability of the channel in the subsequent semiconductor device, which will increase the on-resistance (Rdson) of the semiconductor device and reduce the stability of the withstand voltage value of the semiconductor device

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