Forming method of shallow trench isolation structure

Abstract

The invention provides a forming method of a shallow trench isolation structure. After a first oxide layer is formed by an SACVD (Sub-atmospheric Chemical Vapor Deposition) process, a dry etching process is executed to remove a fragile face of the first oxide layer; then a second oxide layer is formed by the SACVD process. The shallow trench isolation structure formed by the forming method has a good isolation effect; a semiconductor device comprising the shallow trench isolation structure has good stability and is difficult to generate electric leakage and breakdown. Moreover, a hydrogen passivation (H2 passivation) process is added and unsaturated bonds on the surface of a thin film can be removed by the hydrogen passivation process, so that the deposition rate of a subsequent process is stable and uniformity of the thickness of the thin film is finally improved.

Description

technical field [0001] The invention relates to the technical field of integrated circuit manufacturing, in particular to a method for forming a shallow trench isolation structure. Background technique [0002] As semiconductor technology enters the deep sub-micron era, components below 0.18 microns (such as between the active regions of CMOS integrated circuits) are mostly fabricated using shallow trench isolation (STI) for lateral isolation. With the continuous reduction of the feature size of semiconductor devices, the size of the shallow trench isolation structure used for device isolation is also reduced, and correspondingly, the aspect ratio of the isolation trench used to form the shallow trench isolation structure is increased. [0003] In the existing advanced manufacturing process, starting from the 45nm technology node, its shallow trench isolation process has begun to use the sub-atmospheric pressure chemical vapor deposition (SACVD) process to fill the trench ox...

AI Technical Summary

Problems solved by technology

However, compared with the traditional high-density plasma (HDPCVD) process, although the filling capacity of the SACVD process has been greatly improved, but at the same time when this process is applied, a new integration problem arises: in the middle of the trench oxide, a a vulnerable surface (such as figure 1 As shown by the dotted circle in the middle), this fragile surface is very susceptible to erosion by the subsequent wet process, which makes it difficult to control the uniformity of the subsequent process, resulting in poor isolation performance of the shallow trench isolation structure, including shallow trench isolation structures. Semiconductor devices are prone to leakage, which seriously affects the stability of semiconductor devices containing shallow trench isolation structures

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