STI structure and method of forming bottom void in same

Abstract

A method for forming an STI structure is provided. In one embodiment, a trench is formed in a substrate, the trench having a first sidewall and a second sidewall opposite the first sidewall, the sidewalls extending down to a bottom portion of the trench. An insulating material is deposited to line the surfaces of the sidewalls and the bottom portion. The insulating material proximate the top portions and the bottom portion of the trench are thereafter etched back. The insulating material is deposited to line the inside surfaces of the trench at a rate sufficient to allow a first protruding insulating material deposited on the first sidewall and a second protruding insulating material deposited on the second sidewall to approach theretogether. The steps of etching back and depositing are repeated to have the first and second protruding materials abut, thereby forming a void near the bottom of the trench.

Description

technical field [0001] The present invention relates to a manufacturing method of a semiconductor device, and in particular to a method of forming a bottom hole in a shallow trench isolation structure. Background technique [0002] Gaps and trenches, such as those found in STI structures, are commonly used to electrically isolate components on semiconductor devices. Shallow trench isolation structures may include trenches or gaps formed in isolation regions of a semiconductor substrate that are filled with a dielectric material to prevent electrical degradation of nearby component structures (eg, transistors, diodes, etc.) coupling. As the density of components on integrated circuits continues to increase, the distance and size between component structures is gradually shrinking. However, the vertical height of STI structures typically shrinks more slowly than their horizontal width, resulting in larger height-to-width ratios (eg, higher aspect ratios) for gaps and trenche...

AI Technical Summary

Problems solved by technology

However, the recent process used to form the hole near the bottom of the trench can be problematic

For example, the size, shape, location, and density of the aforementioned holes are not completely uniform, which can lead to unpredictable and inconsistent dielectric layer post-deposition processes, such as non-uniform etching, grinding, annealing, etc.

Voids formed in finished components can also cause differences in the dielectric quality of gaps and trenches in the component structure

Unstable and poor device performance due to electrical crosstalk, charge leakage, or even short circuits in the device

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