A method for optimizing shallow trench morphology in soi and bulk regions of fdsoi devices

Abstract

The present invention provides a shallow slot morphology optimization method of an SOI area and a bulk area of an FDSOI (Fully Depleted Silicon on Insulator) device. The method comprises the followingsteps of: providing a FDSOI device substrate; performing SOI layer etching of the structure mentioned above; performing surface oxidation treatment of the structure mentioned above, and forming an oxidation position at a bulk area; performing etching of an SOI area and the bulk area at the same time to the oxidation position; and performing etching processing of the structure mentioned above, andforming an FDSOI device shallow slot isolation structure. The shallow slot morphology optimization method of the SOI area and the bulk area of the FDSOI device provided by the invention employs a method of multi-time in-situ plasma surface oxidation treatment of the bulk area and then layer-by-layer etching to eliminate film difference of the SOI area and the bulk area, and therefore, indifference etching of the two areas is ensured, it is ensured that morphologies of the two areas after etching are smooth and complete and have no boundary and deformation, depth loads of the two areas are reduced, and finally, process and device performances can be improve and stably controlled.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to a method for optimizing the morphology of shallow grooves in SOI and bulk regions of FDSOI devices. Background technique [0002] With the advancement of technology, integrated circuits have developed to the ultra-large-scale nanoscale stage, and the process of bulk silicon substrates and bulk silicon devices is approaching the physical limit. There are severe challenges in further reducing the feature size of integrated circuits. At present, the industry believes that SOI substrates and SOI devices are one of the best solutions to replace bulk silicon substrates and bulk silicon devices. [0003] FDSOI (fully depleted silicon-on-insulator) refers to the basic technology of replacing traditional silicon-on-insulator (i.e., bulk silicon) with silicon-on-insulator. The FDSOI process can effectively reduce parasitic capacitance and improve operating ...

AI Technical Summary

Problems solved by technology

[0004] During the FDSOI multi-layer mask shallow trench isolation etching process, the FDSOI shallow trench isolation process includes the SOI device substrate (HM / SOI / BOX / sub) region and the passive device body (bulk) substrate (HM / silicon) region. Etching, in the original process, the etching program with a small OX / silicon selection ratio is selected to open these two parts at the same time, resulting in a large depth loading in the two regions and an undercut in the OX / sub transition region of the SOI region (undercut) effect

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