Trench isolation structure and forming method thereof

Abstract

The invention provides a trench isolation structure and a forming method thereof. A trench is filled with an oxygen-containing insulating layer; boron ions are injected into the trench, so that boronoxide can be formed; and therefore, an oxygen-containing insulating layer containing the boron oxide can be utilized to form the insulating material of the trench isolation structure, equivalently, the insulating performance of the insulating material of the trench isolation structure is improved, and the isolation performance and trench filling capacity of the trench isolation structure are improved at the same time.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a trench isolation structure and a forming method thereof. Background technique [0002] With the development of semiconductor technology, the size of semiconductor devices tends to decrease and their density gradually increases, especially in the process technology of VLSI (Very Large Scale Integration Circuit, VLSI). As the scale of integration increases, the isolation between adjacent components is particularly important. Usually, a trench isolation structure can be used to realize electrical isolation between adjacent components, and the existing method for forming the trench isolation structure generally includes the following steps. [0003] The first step, specific reference Figure 1a As shown, a substrate 10 is provided, and a mask layer 12 is formed on the substrate 10 , so that a groove 10 a is formed in the substrate 10 using the mask layer 12 as a mask. [0...

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Problems solved by technology

[0010] It should be noted that in the existing formation method, although the high-density plasma process can be used to improve the filling performance of the insulating material layer to the trench, on this basis, it will directly lead to a relatively large thickness of the corresponding deposition on the substrate surface. layer of insulating material, so that the surface of the substrate presents an extremely uneven surface, which will cause the surface after chemical mechanical polishing to be more prone to dishing, resulting in poor flatness of the surface after polishing, which will affect the subsequent The process has adverse effects (for example, it will affect the accuracy of the subsequent photolithography process)

[0011] In addition, when forming the trench isolation structure, it is inevitable to use a high-temperature process, and the high-temperature process will cause a large internal stress in the insulating material layer filled in the trench, thereby affecting the isolation of the trench isolation structure. performance impact

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