Etching liquor for laminated film of aluminium metal film and molybdenum metal film

Abstract

The present invention provides an excellent etching solution capable of not only integrally etching metal laminated films composed mainly of molybdenum-based metal and aluminum-based metal, but also controlling side etching amount of each film, through which the cone angle is controlled within the range of 20-70 degree. Said etching solution capable of etching laminated films of molybdenum-based metal film and aluminum-based metal film forming at insulating film base plates contains sulfonic acid compounds, phosphoric acids and nitric acids, wherein said sulfonic acid compounds are selected from the group of sulphuric acid, ammonium sulfate, sodium sulfate, potassium sulfate, ammonium bisulfate, sodium bisulfate, potassium bisulfate, calcium sulfate, ammonium ceric sulfate, ferric sulfate, copper sulfate, magnesium sulfate, lead sulfate, hydroxyl ammonium sulfate, acylamide sulfate, acylamide ammonium sulfate, ammonium persulphate, ethylenediamine sulfates, aniline sulfates and adenine sulfates.

Description

technical field [0001] The present invention relates to an etchant for etching a laminated film having an aluminum-based metal layer and a molybdenum-based metal layer used in gate, source, and drain electrodes of a thin display. Background technique [0002] Aluminum or a metal material in which impurities such as neodymium, silicon, or copper are added to aluminum is cheap and has very low resistance, so it is used as gate, source, and drain materials for thin displays, and its use is increasing in recent years. [0003] However, aluminum or an aluminum alloy is easily corroded by a chemical solution or heat. Therefore, a laminated film formed of molybdenum or a molybdenum alloy film on top of aluminum or an aluminum alloy is used as an electrode material. [0004] As a processing technique for patterning such a metal laminated film, patterning is performed by etching with chemicals such as phosphoric acid using a photoresist pattern formed on the metal surface by photolit...

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Problems solved by technology

[0007] However, in the case of using the above-mentioned mixed acid in the above-mentioned laminated film, since the standard electrode potential of the aluminum-based metal and the molybdenum-based metal are different, the etching rate is different from that in the case of a single-layer film. The cone angle of the metalloid is controlled at 20-70 degrees

[0008] In addition, as an etchant for the molybdenum-based metal film, it has been reported that the cone shape of the molybdenum-based metal film can be controlled by wet etching twice. However, since the chemical solution and the etching tank must be divided into two tanks, there is a problem of high cost. (Patent Document 5)

[0009] In addition, an etchant for a laminated film of a molybdenum-niobium alloy film and an aluminum-based metal film is reported, and the etchant contains organic acids such as phosphoric acid, nitric acid, acetic acid, or alkylsulfonic acid, but there is no description of an etchant using an inorganic sulfonic acid compound ( Patent Document 6)

[0010] As an etchant for a laminated film of a molybdenum-based metal film and an aluminum-based metal film, a composition containing a cation-generating component such as sodium hydroxide in phosphoric acid, nitric acid, or acetic acid has been disclosed, but there is a problem that concentration control is difficult (Patent Document 7 )

[0011] In addition, as a composition for etching an upper electrode made of Al or Mo material used in the manufacture of a thin film EL panel, a mixed solution of phosphoric acid, nitric acid, and sulfuric acid has been reported, but the combination of molybdenum-based metal film and aluminum-based metal film has not been disclosed. The stacked film of the metal film is etched in its entirety while controlling the taper angle (Patent Document 8)

[0012] In addition, it is reported that a mixed acid containing phosphoric acid, acetic acid, nitric acid, and sulfuric acid is put from the inside of a resist pattern to etch a Mo thin film for a thin film transistor, but no attempt has been made to laminate a molybdenum-based metal film and an aluminum-based metal film. The entire film is etched while controlling the taper angle (Patent Document 9)

[0013] In addition, it is reported that a gate line composed of an aluminum alloy layer and a molybdenum layer is completely etched by wet etching with an etchant containing a compound for maintaining an acidic atmosphere such as nitric acid, iron compound, fluorine compound, and perchloric acid. However, it does not disclose the overall etching of gate lines composed of aluminum alloy layer and molybdenum layer using an etchant containing phosphoric acid, nitric acid and sulfonic acid compounds (Patent Document 10)

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