Etching solution for multilayer thin film having copper layer and molybdenum layer contained therein

Abstract

Discloses are an etching solution for a multilayer thin film having a copper layer and a molybdenum layer contained therein; and an etching method of a multilayer thin film having a copper layer and a molybdenum layer contained therein using the same. Specifically disclosed are an etching solution for a multilayer thin film having a copper layer and a molybdenum layer contained therein, which includes (A) hydrogen peroxide, (B) a fluorine atom-free inorganic acid, (C) an organic acid, (D) an amine compound having a carbon number of from 2 to 10 and having an amino group and a hydroxyl group in a total group number of 2 or more, (E) an azole, and (F) a hydrogen peroxide stabilizer, and which has a pH of from 2.5 to 5; and an etching method using the same.

Description

TECHNICAL FIELD[0001]The present invention relates to an etching solution for a multilayer thin film having a copper layer and a molybdenum layer contained therein. In particular, the etching solution of the present invention is favorably used for etching a multilayer thin film having a copper layer is provided on a molybdenum layer.BACKGROUND ART[0002]Heretofore, aluminium or an aluminium alloy has been generally used as the wiring material for display devices such as flat panel displays, etc. However, with growing in size and increasing in resolution of displays, there has occurred a problem of RC delay caused by the characteristics such as the wiring resistance of such aluminium-based wiring materials and uniform panel displaying has tended to be difficult.[0003]Given the situation, the recent tendency is toward investigation of employing copper or copper-based wiring with a material having a lower resistance. However, copper has an advantage in that its resistance is low but, on...

AI Technical Summary

Benefits of technology

[0013]According to the present invention, there are provided an etching solution which secures, in an etching process for a multilayer thin film containing a copper layer and a molybdenum layer, high processing accuracy, little etching residue and unevenness and a long bath life, and realizes a good wiring profile after etching therewith, and which therefore can meet the requirement of size enlargement and resolution enhancement of displays, and an etching method using it for a multilayer thin film containing a copper layer and a molybdenum layer. According to the etching method, a wiring material that contains a multilayer thin film containing a copper layer and a molybdenum layer can be etched all at a time, and therefore, after etching therewith, a good wiring profile can be realized at high producibility.

[0014]The etching solution of the present invention is used for etching of a multilayer thin film having a copper layer and a molybdenum layer contained therein, and it comprises (A) hydrogen peroxide, (B) a fluorine atom-free inorganic acid, (C) an organic acid, (D) an amine compound having a carbon number of from 2 to 10 and having an amino group and a hydroxyl group in a total group number of 2 or more, (E) an azole, and (F) a hydrogen peroxide stabilizer, and has a pH of from 2.5 to 5.

[0015]Hydrogen peroxide which is used in the etching solution of the present invention has a function to oxidize a copper wiring as an oxidizing agent and also has a function to oxidize and dissolve molybdenum. A content of hydrogen peroxide in the etching solution is preferably from 3 to 10% by mass, and more preferably from 4.5 to 7.5% by mass. The content of hydrogen peroxide falling within the above range is preferred, the control of hydrogen peroxide is easy, and also as securing a suitable etching rate and facilitating good control of the etching amount. Thus, such is preferable.

[0016]The fluorine atom-free inorganic acid which is used in the etching solution of the present invention contributes to the dissolution of copper which has been oxidized with the hydrogen peroxide (A). In the present invention, from the viewpoint of environmental measure, a fluorine atom-free acid is adopted. As the fluorine atom-free inorganic acid, sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, hypophosphorous acid, carbonic acid, sulfamic acid, boric acid, and the like are preferably exemplified. These can be used alone or in admixture of a plurality thereof. Above all, sulfuric acid and nitric acid are preferable.

[0017]A content of the inorganic acid (B) in the etching solution is preferably from 0.01 to 5% by mass, and more preferably from 0.01 to 3% by mass. When the content of the inorganic acid falls within the above range, a suitable etching rate can be secured and a good wiring profile can be obtained after etching.

[0018]The organic acid which is used in the etching solution of the present invention contributes to the etching of copper and molybdenum and the removal of a residue to be caused due to molybdenum, and the content thereof in the etching solution is preferably from 1 to 15% by mass, more preferably from 5 to 13% by mass. When the content of the organic acid falls within the above range, etching of copper and molybdenum and the removal of a residue to be caused due to molybdenum can be sufficiently achieved, and also, a good wiring profile can be obtained after etching. Also, the organic acid functions as a masking agent of a copper ion to be contained in the etching solution after etching and is able to inhibit the decomposition of hydrogen peroxide with copper.

Problems solved by technology

However, with growing in size and increasing in resolution of displays, there has occurred a problem of RC delay caused by the characteristics such as the wiring resistance of such aluminium-based wiring materials and uniform panel displaying has tended to be difficult.

However, copper has an advantage in that its resistance is low but, on the other hand, has a problem in that, in use for gate wiring, the adhesiveness between the substrate such as glass or the like and copper is not sufficient and that, in use for source / drain wiring, copper may diffuse into the silicon semiconductor underlayer.

However, these are all unsatisfactory in point of the wiring profile after etching therewith and, as a result, could not often sufficiently meet the size enlargement and the resolution enhancement of displays.

Also, the etching solution disclosed in Patent Reference 2 contains a fluorinated compound, so that it was not thoroughly satisfactory from the viewpoint of environmental measure.

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