Method of manufacturing buried word lines and isolating structures thereof

Abstract

A method of manufacturing buried word lines and isolating structures thereof comprises the following steps of forming a plurality of buried word lines inside a substrate, wherein the top of each buried word line is lower than the surface of the substrate; forming a mask structural layer inside a groove on each buried word line, making the mask structural layer protrude by removing a part of the structure so that side walls of the mask structural layer form distance pieces and a plurality of self-aligned grooves are further formed; removing substrate parts under the grooves in an etching way with the distance pieces and the mask structural layers as the etching masks so as to form a plurality of isolating structure grooves; and further forming isolating structures inside the isolating structure grooves. By means of the manufacturing method, interference (Row Hammer) among word lines can be effectively alleviated. Furthermore, the area of a contact zone inside an active region can be kept.

Description

technical field [0001] The invention relates to a method for manufacturing a buried word line and its isolation structure, and in particular to a method for manufacturing a self-aligned buried word line isolation structure. Background technique [0002] In order to increase the integration of DRAM to speed up the operation speed of components, and to meet the needs of consumers for miniaturized electronic devices, a buried word line DRAM (buried wordline DRAM) has been developed in recent years to meet the above-mentioned needs. [0003] However, as the density of memory increases, the pitch of word lines and the isolation structure of memory arrays will continue to shrink, resulting in various adverse effects. For example, cell-to-cell leakage between memories, interference between word lines (also known as RowHammer), read and write time failure (tWR failure), retention failure (retention failure), bit line coupling failure (BitLine coupling failure), etc. [0004] There...

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Problems solved by technology

[0006] However, because the size of the element itself is very small, it is likely to be caused by a small offset in the photolithography process. figure 2 the result of

exist figure 2 In , because the buried word line 106 is slightly shifted to the right, the area A2 of the contact region 112 becomes significantly smaller, which leads to an increase in the resistance value here and affects the performance of the device itself

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