Method for manufacturing trench and method for manufacturing shallow trench isolation structure

Abstract

The invention provides a manufacturing method for grooves and a manufacturing method for shallow groove isolating structures. The manufacturing method for the grooves comprises the steps of in a samereaction cavity, forming a first groove in a semiconductor substrate, and repeatedly and cyclically carrying out a first reactive ion etching process to vertically deepen the first groove downward, wherein an etching gas mainly generating polymers is adopted in a first deposition step of the first reactive ion etching process, and an etching gas mainly used for anisotropic etching of the substrateis adopted in a first etching step of the first reactive ion etching process; repeatedly and cyclically carrying out a second reactive ion etching process, wherein the second reactive ion etching process comprises a second deposition step and a second etching step which are carried out in sequence, and the etching gas adopted in the second etching step converts into the etching gas mainly used for isotropic etching of the substrate. By the manufacturing method for the grooves, spherical grooves are formed at the bottom of the first groove, and the shape and critical dimension of the first groove are maintained.

Description

technical field [0001] The invention relates to the technical field of integrated circuit manufacturing, in particular to a method for manufacturing a trench and a method for manufacturing a shallow trench isolation structure. Background technique [0002] Shallow trench isolation is a common technology for electrical isolation of devices in 0.18um~20nm logic semiconductor chips. The general process of the STI (Shallow Trench Isolation) manufacturing process is: first form a trench to limit the active area on the semiconductor substrate, and then use An insulating material (usually silicon oxide) is used to fill the trench to form a shallow trench isolation structure. With the continuous advancement of semiconductor chip generations, the size of the chip is getting smaller and smaller, and the size of the shallow trench isolation structure is also shrinking, which causes the contradiction between the difficulty of the shallow trench isolation process and the device isolation...

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Problems solved by technology

[0009] The problem with the above-mentioned manufacturing method of the novel STI structure is that the process steps are relatively complicated. Compared with the manufacturing process of the V-shaped traditional STI structure, from the first step of etching to the fifth step of cleaning, at least more deposition of the insulating layer 104 is required. , the anisotropic etching of the insulating layer 104, and the etching of the spherical groove 105, these steps need to be realized through multiple process machine conversions, which increases the process time and process machine The defect occurrence rate in the conversion, the corresponding process cost is also relatively high

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