Method for wet cleaning after dry etching of aluminum wire

Abstract

The invention discloses a method for wet cleaning after dry etching of an aluminum wire. The method comprises a first step of pre-treating the surface of a wafer with deionized water, reacting the deionized water with the aluminum chloride remained in a polymer after dry etching and forming aluminum hydroxide and chlorine, pumping out chlorine in a cleaning machine with the exhaust air, and thus removing the CL element; a second step of performing wet cleaning on the pre-treated wafer by using of a fluorine-based chemical solution including NH4F to remove the polymer produced by dry etching onthe wafer, and reacting NH4F with the aluminum hydroxide produced in the first step to form NH4ALF4; and a third step of post-treating the surface of the wafer with deionized water, and using the deionized water to dissolve NH4ALF4 so as to remove the F element, so that the anti-corrosion immunity of the wafer aluminum wire is improved by removing the CL element and the F element. The method in the invention can improve the anti-corrosion immunity of aluminum.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit manufacturing method, in particular to a wet cleaning method after aluminum wire dry etching. Background technique [0002] In integrated circuit manufacturing, chips are all formed on the same wafer, and aluminum interconnection lines need to be formed in the subsequent process of chip manufacturing to realize the electrical connection of each device. After the aluminum layer is formed, aluminum lines need to be formed by a photolithography process, and through holes need to be formed between the aluminum lines of different aluminum layers for connection. Notice that aluminum lines are formed by dry etching after photolithographic definition, and polymer residues will be produced after dry etching, including ALCL3, ALF3, AL(OH)3, etc. [0003] In the prior art, a wet cleaning process is used to remove the polymer after the dry etching of the aluminum wire. The wet cleaning process for removi...

AI Technical Summary

Problems solved by technology

[0009] The Cl elements produced during the dry etching of aluminum wires and the F elements produced during the wet fluorine-based liquid cleaning process are likely to cause aluminum corrosion. Experiments have found that if there are Cl and F elements remaining after the existing wet cleaning is completed , since CL and F will react with aluminum, it will eventually cause aluminum corrosion

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