Shallow trench isolation structure and method of making the same

Abstract

The invention provides a shallow trench isolation structure and a manufacturing method thereof, comprising: firstly, forming a nitride mask layer on a substrate, and etching the nitride mask layer and the substrate to form trench; then, filling the isolation oxide layer in the trench, the isolation oxide layer fills the trench, and buries the nitride mask layer; then, proceeds to the isolation oxide layer ion implantation, so that part of the height region of the isolation oxide layer in the trench is converted into a first barrier layer; finally, removing the nitride mask layer and removing the isolation oxide layer above the first barrier layer, to form shallow trench isolation structures. The technical solution provided by the present invention prevents etching of the step of the shallow trench isolation structure by an etchant such as hydrofluoric acid, so as to accurately control the step height of the shallow trench isolation structure, thereby improving the reliability of the device. performance.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to a shallow trench isolation structure and a manufacturing method thereof. Background technique [0002] In the field of integrated circuit manufacturing, the step height is a very important parameter. Controlling the step height can increase a lot of process margins for subsequent processes (such as the focal depth of gate lithography, gate etching, etc.). In the existing process technology, the initial step height is generally defined through shallow trench isolation (STI) process, refer to figure 1 The step height S1 of the shallow trench isolation 12 on the substrate 11; the step height of the shallow trench isolation is controlled by subsequent hydrofluoric acid etching. In the actual process, there are generally multiple times of hydrofluoric acid etching, and after each hydrofluoric acid etching, the step height of shallow trench isolation will be different. ...

AI Technical Summary

Problems solved by technology

However, in the actual production process, due to the influence of factors such as the accuracy of the equipment and the concentration of hydrofluoric acid, it is impossible to accurately control the step height of shallow trench isolation by adjusting the etching process of hydrofluoric acid.

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