A method for forming shallow trench isolation

Abstract

The invention discloses a method for forming shallow trench isolation. The method comprises the following steps: S01: forming fin structures perpendicular to a substrate on the substrate; S02: using silicon tetrachloride and oxygen as an etching gas to etch the substrate between the adjacent fin structures to obtain shallow trench isolation that tapers from the upper portion to the lower portion of the substrate and a silicon oxide layer covering the sidewalls and upper surface of the fin structures; and S03, removing the silicon oxide layer described above to form the shallow trench isolationbetween the fin structures. The method for forming the shallow trench isolation of the invention adopts different etching methods to form the fin structure and the shallow trench isolation, thereby simultaneously satisfying different requirements for angles between the fin structures and the shallow trench isolation and the substrate surface.

Description

Technical field [0001] The invention belongs to the field of integrated circuit technology, and specifically relates to a method for forming shallow trench isolation. Background technique [0002] With the continuous development of semiconductor technology, traditional planar devices have been unable to meet people's demand for high-performance devices. A fin field-effect transistor (Fin Field-Effect Transistor, FinFET) is a three-dimensional device that includes a fin vertically formed on a substrate and a stacked gate intersecting the fin. This design can greatly improve circuit control and reduce leakage ports, while also greatly reducing the gate length of the transistor. [0003] See figure 1 , figure 1 It is a schematic diagram of a three-dimensional structure of an existing fin field effect transistor. Such as figure 1 As shown, the fin field effect transistor structure includes: a semiconductor substrate 10 at the bottom layer, on which a convex fin portion 14 is formed, ...

AI Technical Summary

Problems solved by technology

The current technology is difficult to take into account the required angle of fin structure and shallow trench isolation, and the shape is difficult to control

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