Method for precleaning thin film surface oxide before deposition

Abstract

The invention provides a method for pre-cleaning oxide on the surface of a thin film before sedimentation. The pre-cleaning method adopts a dry-method chemical pre-cleaning process which mainly comprises the following steps: A, a remote plasma etching step: etching gas comprises nitrogen fluoride and ammonia gas; the nitrogen fluoride and ammonia gas are converted into fluoride through plasma with low power; and the fluoride reacts with the oxide on the surface of the thin film to generate silicate; and B, an in-situ annealing step: the silicate obtained in the step A is heated and sublimed to a gaseous state; and the gaseous silicate is pumped out. The disclosed method for pre-cleaning the oxide on the surface of the thin film before sedimentation adopts the dry-method chemical pre-cleaning process, can effectively clean the natural oxide of the bottom of a contact layer, can not degrade the performance of a device on the bottom layer and can simultaneously reduce the contact resistance.

Description

technical field [0001] The invention belongs to the field of chip manufacturing, and relates to a metal thin film deposition process, in particular to a method for pre-cleaning oxides on the thin film surface before deposition. Background technique [0002] The surface of a silicon wafer has multiple microchips, and each chip has millions of devices and interconnection lines, which are very sensitive to contamination. As chip feature sizes shrink to accommodate higher performance and higher levels of integration, the need to control surface contamination becomes increasingly critical. [0003] In the process before the deposition of the contact glue layer, the chip needs to be pre-cleaned to clean the natural oxide and other impurities on the surface of the film. [0004] The existing pre-cleaning step is usually achieved by argon plasma bombardment. This physical bombardment is difficult to fully and effectively remove the natural oxide at the bottom of the contact hole an...

AI Technical Summary

Problems solved by technology

[0004] The existing pre-cleaning step is usually achieved by argon plasma bombardment. This physical bombardment is difficult to fully and effectively remove the natural oxide at the bottom of the contact hole and the residue formed by a series of previous processes such as wet chemical stripping, which makes the contact resistance biased. High, and the argon plasma bombardment will also cause damage to the device at the bottom of the contact layer, affecting the performance of the transistor

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