Method for manufacturing shallow trench isolation structure

Abstract

The invention provides a method for manufacturing a shallow trench isolation structure. The method includes sequentially covering an oxide layer and a nitride layer on a semiconductor substrate; carrying out exposure and etching processes to form shallow trench patterns; settling isolation layers and filling the isolation layers in the shallow trench patterns; flattening the isolation layers and reserving parts of the isolation layers; removing remaining parts of the isolation layers by means of dry etching; and removing the nitride layer by means of wet etching. The method for manufacturing the shallow trench isolation structure has the advantages that the nitride layer is unaffected when the isolation layers are flattened, the isolation layers can be flattened by common grinding fluid, the cost of the grinding fluid is reduced, the remaining parts, which are positioned on the nitride layer, of the isolation layers are removed by means of dry etching, and accordingly problems of depression and erosion due to chemical mechanical polishing are solved.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuits and its manufacture, in particular to a method for manufacturing a shallow trench isolation structure. Background technique [0002] In recent years, with the development of semiconductor integrated circuit manufacturing technology, the number of components contained in the chip has been increasing, and the size of the components has been continuously reduced due to the improvement of integration. However, no matter how the device size is reduced, there must still be proper insulation or isolation between the various devices in the chip in order to obtain good device properties. The technology in this area is generally called Device Isolation Technology (Device Isolation Technology). More chip area to accommodate more components. [0003] Among various component isolation technologies, the local silicon oxidation method (LOCOOS) and the shallow trench isolation structure (Shallow...

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Problems solved by technology

[0005] The traditional production method uses relatively expensive high-selection ratio polishing fluid to grind the silicon dioxide layer for planarization, which is relatively expensive, and an appropriate amount of over-grinding must be added after grinding to the silicon nitride surface to ensure that the silicon nitride surface is free of damage. Silicon oxide remains, resulting in a depression (Disshing) on ​​the silicon oxide surface in the large-area pattern area 103, and an erosion (Erosion) phenomenon in the silicon oxide in the high-density pattern area 104, which weakens the planarization effect and ultimately reduces the shallow trench isolation device. Isolation

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