Semiconductor structures and methods of forming them

Abstract

A semiconductor structure and a method for forming the same, the method comprising: providing a substrate, the substrate includes adjacent device regions and isolation regions, discrete fins are formed on the substrate, and between adjacent fins The distances are equal; a protective layer is formed on the sidewall of the fin; the protective layer and the fin with a partial thickness of the isolation region are etched and removed by the first etching process; the remaining protective layer is used as a mask, and the second etching is used etching the remaining fins of the isolation region to form dummy fins; after the second etching process, removing the remaining protective layer; after removing the remaining protective layer, forming an isolation structure on the substrate , the top of the isolation structure is lower than the top of the device region fin and higher than the top of the dummy fin. The invention divides the step of etching the fin of the isolation region into two steps, thereby increasing the etching process window for removing the fin of the isolation region and reducing the etching damage to the fin of the adjacent device region.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a semiconductor structure and a forming method thereof. Background technique [0002] In the field of semiconductor manufacturing, with the development trend of VLSI, the feature size of integrated circuits continues to decrease. In order to adapt to the reduction of feature size, the channel length of MOSFET field effect transistors is also continuously shortened accordingly. However, as the channel length of the device is shortened, the distance between the source and the drain of the device is also shortened, so the control ability of the gate to the channel becomes worse, and the gate voltage pinches off the channel. The difficulty is also increasing, making the phenomenon of subthreshold leakage (subthreshold leakage), the so-called short-channel effect (SCE: short-channel effects) more likely to occur. [0003] Therefore, in order to better adapt to the reductio...

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Problems solved by technology

[0004] However, the electrical performance of prior art semiconductor structures needs to be improved

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