A cleaning method for a contact hole

Abstract

The invention provides a method for cleaning a contact hole and a method for forming a contact of a semiconductor device. The residual oxide and / or natural oxide in the contact hole can be completely removed by adopting a dry first and then wet cleaning process without damaging the contact hole The bottom and the contact hole shape change, therefore, the contact performance between the metal plug and the contact area is better, and the semiconductor device has a lower contact resistance.

Description

technical field [0001] The invention relates to the technical field of semiconductor technology, and more particularly, to a method for cleaning a contact hole. Background technique [0002] For semiconductor devices, the contact resistance accounts for a large proportion of the interconnection resistance, so reducing the contact resistance is very important. Usually, in the semiconductor manufacturing process, after the etching of the contact hole is completed, there may be oxide residues at the bottom of the hole, or during the waiting process, the bottom of the hole that has not yet been filled may be oxidized to produce natural oxide , these oxides will adversely affect the subsequent filling process of the contact hole, and finally cause the contact resistance to be too large or unstable. [0003] Therefore, after the contact hole is formed by etching, the contact hole needs to be cleaned to remove residual oxide or natural oxide in the contact hole. In the prior art,...

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Problems solved by technology

However, in the actual process, the dielectric layer ILD on the Si semiconductor is thicker, and the width of the contact hole needs to be narrower, which will make the contact hole A formed in the dielectric layer ILD and in contact with the Si substrate semiconductor as deep as possible. In this case, if dry cleaning is still used to clean the oxide B at the bottom of the contact hole A, the bottom of the contact hole A may not be cleaned thoroughly, and there will still be a small amount of residual oxide B, such as figure 2 shown

[0004] For the cleaning of contact holes with a large depth-to-width ratio, it is not suitable to directly use wet cleaning instead of dry cleaning, because wet cleaning has isotropic characteristics, and if the cleaning time is too long, the morphology of the contact holes will change, thereby affecting adverse effects on semiconductor devices

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