Isolation trench film filling structure, semiconductor memory device and preparation method

Abstract

The invention provides an isolation trench film filling structure, a semiconductor memory device and a preparation method. The preparation method of the isolation trench film filling structure comprises the steps that a semiconductor substrate with a peripheral groove is provided; a prefabricated filling material is formed on the semiconductor substrate, and the upper surface of the semiconductorsubstrate and the sidewall and the bottom of the peripheral groove are covered to form a neck; the prefabricated filling material is pre-etched to remove the neck; a high-density plasma oxide materialis formed on the semiconductor substrate; the prefabricated filling material is covered, and the peripheral groove is filled; and extra high-density plasma oxide material and prefabricated filling material are removed to acquire a high-density plasma oxide material layer and a prefabricated filling layer in the peripheral groove. According to the invention, the shape of the prefabricated fillinglayer is improved through pre-etching; voids between the high-density plasma oxide material and the prefabricated filling material are prevented; and device failure caused by short circuit caused by asubsequently formed metal bit line is prevented.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an isolation trench film filling structure, a semiconductor storage device and a preparation method. Background technique [0002] Patterning can generate topological shapes with three spatial dimensions on the wafer surface, which form gaps and steps on the wafer surface. A small gap (such as an isolation trench or via) can be described by an aspect ratio, which is defined as the ratio of the depth to the width of the gap. In device fabrication, the ability to fill small gaps on the silicon wafer surface becomes the most important film property. For small gaps, high / low aspect ratios make it difficult to deposit films with uniform thickness, and pinch-offs and voids can occur. With the continuous reduction of the feature size of high-density integrated circuits, it is very important to perform a uniform and void-free filling deposition process for gaps with high / low asp...

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Problems solved by technology

[0008] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide an isolation trench film filling structure, a semiconductor storage device and a preparation method, which are used to solve the problem of high / low aspect ratio isolation trenches in the prior art. Voids are easy to be generated during the filling process, resulting in the short circuit of the subsequently formed metal bit lines and the failure of the device

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