Method for improving alignment of lithography mark, epitaxial layer for alignment of lithography mark, and preparation method for super-junction

Abstract

The invention discloses a method for improving the alignment of a lithography mark, an epitaxial layer for the alignment of the lithography mark, and a preparation method for a super-junction, and belongs to the field of micro-electronic chips. The method comprises the steps: providing a substrate with an epitaxial layer, wherein the epitaxial layer is provided with a groove which is far from thetop surface far of the substrate and extends inwards from the top surface, the groove is limited by a bottom wall and a side wall, the bottom wall is parallel to the top surface of the epitaxial layer, and the side wall extends towards the epitaxial layer along the top surface; and forming films on a part of the side wall or on the whole side wall. The method facilitates the obtaining of the better and easier alignment effect in the subsequent manufacturing process during lithography marking.

Description

technical field [0001] The invention relates to the field of microelectronic chip production and manufacturing, in particular to a method for improving the alignment of photolithographic marks, an epitaxial layer and a super junction preparation method for photolithographic mark alignment. Background technique [0002] The SuperJunction (super junction) structure in PowerMOSFET (power metal oxide semiconductor field effect transistor) is an innovative structure on the withstand voltage layer. This structure has the characteristics of low on-resistance, high withstand voltage, and low heat generation, and overcomes the "silicon limit" of traditional MOSFETs. [0003] In the manufacturing process of super junction products, a specific well region structure is often achieved through multiple epitaxial growth, photolithography, and implantation steps. Since the epitaxial growth is a large-area doped growth along the crystal direction on the chip, the overall thickness of the ch...

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Problems solved by technology

Since the epitaxial growth is a large-area doped growth along the crystal direction on the chip, the overall thickness of the chip increases after each epitaxial growth, and the shape of the lithography mark also changes accordingly, making it difficult for the lithography machine Automatic Identification

[0004] In the early stage of the manufacturing process, the lithographic mark recognition of the lithography machine can be improved by multiple lithography and corrosion methods, but the probability of chip contamination increases during the process of film transfer and film making, and the quality of the subsequent epitaxial layer is difficult. ensure

If this problem occurs in the mass production stage of super junction products, it will occupy the capacity of the production line, increase the cost of the product, and seriously affect the production efficiency of the product

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