Equiplanar field oxidation isolation structure and method for forming the same

Abstract

Provided are an isoplanar field oxidation isolation structure and a forming method thereof. The method comprises the steps of providing a substrate, forming a silicon oxide layer on the substrate, forming a first silicon nitride layer on the silicon oxide layer, carrying out patterning, forming slots in preset areas to expose the substrate, removing the substrate parts in the slots to form grooves, forming silicon nitride side walls on the inner walls of the grooves, growing field oxide layers in the grooves, enabling the surfaces of the field oxide layers to be flushed with the surface of the substrate outside the grooves, and removing the first silicon nitride layer and the silicon oxide layer outside the grooves. According to the forming method of the isoplanar field oxidation isolation structure, the isoplanar field oxidation isolation structure can be obtained, meanwhile, the silicon nitride side walls are formed on the inner walls of the grooves, transverse peroxidation can be prevented, and the area of an active area is maintained the same.

Description

technical field [0001] The invention relates to the technical field of ultra-deep submicron semiconductor devices, in particular to an equal-plane field oxidation isolation structure and a forming method thereof. Background technique [0002] Nowadays, tens of thousands of semiconductor devices are integrated in a semiconductor integrated circuit. In order to avoid mutual influence between the devices, it is usually necessary to form isolation between the devices. [0003] The traditional isolation method is local field oxidation isolation (LOCOS). In the traditional LOCOS formation method, a silicon nitride layer is first grown on the surface of the silicon substrate, and the silicon nitride layer in the field area is removed by photolithography and etching to form an opening to expose the silicon substrate. A field oxide layer is formed on the bottom, and then the silicon nitride layer on the surface of the silicon substrate is removed, thereby forming an active region (d...

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Problems solved by technology

However, the shallow trench isolation process has higher requirements on equipment, which increases the process cost

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