Semiconductor structure and formation method thereof

Abstract

The present invention provides a semiconductor structure and a formation method thereof. The method comprises the steps of: providing a substrate and fins protruding from the substrate, wherein each fin comprises a fin first portion located at the surface of the substrate and a fin second portion located at the top portion of the fin first portion; forming first laying layers at the side walls ofthe fin first portions; forming second laying layers at the surfaces of the first laying layers and the top portions and the side walls of the fin second portions; forming isolation films covering thesecond laying layer on the substrate, wherein the top portions of the isolation films are higher than the top portions of the fins and are levelled with the top portions of the fins; removing the second laying layers and the isolation films higher than the top portions of the fin first portions, wherein the remaining isolation films form isolation layers; and forming gate oxide layers at the surfaces of the top portions and the side walls of the fins exposed on the isolation layers. In the invention, the first laying layers and the second laying layers can effectively weaken the stress applied to the side walls of the fins so as to avoid bending of the fins, and the formed process window of the isolation layers is large which facilitates improvement of the formation quality of the isolation layers.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a semiconductor structure and a forming method thereof. Background technique [0002] In semiconductor manufacturing, as the feature size of integrated circuits continues to decrease, the channel length of MOSFETs has also been 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, resulting in poor control ability of the gate to the channel, and short-channel effects (SCE: short-channel effects) more likely to happen. [0003] The Fin Field Effect Transistor (FinFET) has outstanding performance in suppressing the short channel effect. The gate of the FinFET can control the fin at least from both sides. Therefore, compared with the planar MOSFET, the gate of the FinFET has an The control ability is stronger, and the short channel effect can be well suppr...

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Problems solved by technology

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

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