Method of cleaning wafer surfaces after polishing aluminum wirings in ultra large scale integrated circuits

Abstract

A method of cleaning wafer surfaces after polishing aluminum wirings by means of a polishing disc in ultra large scale integrated circuits, the method including: a) mixing and stirring deionized water, between 0.5 and 5 wt. % of a surfactant, between 0.1 and 5 wt. % of an FA/O II chelating agent, and between 0.01 and 5 wt. % of an FA/O II corrosion inhibitor, to yield a neutral aqueous cleaning solution; and b) after a chemical-mechanical polishing treatment for aluminum wirings, directly washing wafer surfaces with the neutral aqueous cleaning solution without lifting the polishing disc.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of International Patent Application No. PCT / CN2010 / 080471 with an international filing date of Dec. 30, 2010, designating the United States, now pending, and further claims priority benefits to Chinese Patent Application No. 201010231677.8 filed Jul. 21, 2010. The contents of all of the aforementioned applications, including any intervening amendments thereto, are incorporated herein by reference. Inquiries from the public to applicants or assignees concerning this document or the related applications should be directed to: Matthias Scholl P.C., Attn.: Dr. Matthias Scholl Esq., 14781 Memorial Drive, Suite 1319, Houston, Tex. 77079.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The invention relates to a polishing technique, and more particularly to a method of cleaning wafer surfaces after polishing aluminum wirings in ultra large scale integrated circuits.[0004]2. Descriptions o...

AI Technical Summary

Benefits of technology

[0014]Advantages of the invention are summarized below: aqueous cleaning is quickly processed after CMP treatment without stopping rotation of the polishing disc, a large flow rate of the neutral aqueous cleaning solution containing surfactant, chelating agent, and corrosion inhibitor can clean wafer surfaces with no corrosion to device, and wash away unevenly distributed polishing solution, organic matters and large grains, thereby obtaining a clean and perfect surface. The surfactant reduces the surface tension of wafers, and the cleaning solution can expand evenly on the wafer surfaces, thus, the effectiveness of the clean is improved. The chelating agent reacts with metal ions forming chemical bonds to yield macromolecular chelates, thereby effectively controlling the adsorption of metal ions on the wafer surfaces, and washing away metal ions using large flow rate of cleaning solution. The corrosion inhibitor forms a single molecular passive film on the surface to prevent residue of polishing solution from continuing reacting with the surface and forming uneven corrosion and oxidation, so that the perfection of the wafer surface is improved.

Problems solved by technology

Shortly after CMP, chemical adsorption further occurs between the surface and dirt, and the dirt is difficult to remove, thereby resulting in contamination.

Due to uneven distribution of polishing solution residues and barriers of adsorbed large grains, chemical corrosion and oxidation occurs unevenly on the surface, and the performance of the surface is decreased and cannot meet the standard.

Conventional treatment after CMP is to lift polishing discs from the polishing solution to deionized water to wash, due to the time delay and cleaning solution only containing deionized water, the effectiveness is not good but often seriously contaminated by organic matters, large grains, and metal ions.