Method of restraining notch appearing at bottom of hole during etching process, and hole forming method

Abstract

The invention provides a method of restraining a notch appearing at the bottom of a hole during an etching process, and a hole structure forming method. The hole structure forming method mainly comprises the following steps: (1) a substrate is provided, wherein the substrate comprises an to-be-etched material layer and an insulated layer attached to the lower surface of the to-be-etched material layer; (2) the to-be-etched material layer is subjected to anisotropic plasma etching, and a hole is formed initially; and (3) in a relatively-low working air pressure environment, anisotropic plasma etching is continued to deepen the hole. At least when the process of deepening the hole is over, the insulated layer can be exposed through the hole.

Description

technical field [0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a method of using plasma to etch in a material layer to be etched to form a through hole penetrating through the material layer, which is used to suppress the gap at the bottom of the through hole (that is, the intersection between the material layer and the lower insulating layer). interface) there is a phenomenon of notching. Background technique [0002] It is one of the most common processes in semiconductor processing to form via holes in material layers by means of anisotropic plasma etching. Such as figure 1 When etching silicon (or other materials) 1 , due to the electrical isolation of the underlying insulating layer (such as silicon oxide) 2 , a large amount of charges will accumulate on the silicon 1 . Due to the influence of charges, when the etching reaches the interface between the silicon 1 and the insulating layer 2 , notches 4 will be gene...

AI Technical Summary

Problems solved by technology

[0003] In some applications, the notch should be avoided as much as possible, because the presence of the notch itself has destroyed the shape of the feature (ie hole), which in turn deteriorates the performance of the device.

Not only that, the gap will also cause problems for subsequent processing processes (such as filling holes)

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