Etching solution composition for metal thin film consisting primarily of copper

Abstract

The problem of the present invention is to provide an etching solution composition that can etch with high accuracy a metal-laminated film pattern comprising thin films of copper and a copper alloy, can form an excellent pattern shape, and has practically excellent and stable characteristics with long solution life, and to provide an etching method using such etching solution composition. The present invention relates to an etching method for etching a metal-laminated film having a layer consisting of copper and a layer consisting of a copper alloy containing copper, using an etching solution composition comprising phosphoric acid, nitric acid, acetic acid and water, as well as to said etching solution composition.

Description

technical field [0001] The present invention relates to an etching solution composition for etching a metal laminated film of copper and a copper alloy containing copper as a main component used in the manufacture of flat panel displays and the like, and an etching method using the etching solution composition. Background technique [0002] Aluminum thin films have conventionally been used as fine wiring materials for liquid crystal display devices, but in recent years, copper thin films having lower resistance characteristics than aluminum have attracted attention (see Patent Documents 1 and 2). [0003] In the past, copper has been used as a metal material for forming patterns for printed circuit boards, but as drive transistor electrodes and fine patterns of flat panel displays, in order to form patterns with a line width of several microns or less, copper and copper-based components have not been used so far. copper alloy. Therefore, the copper thin film etching technol...

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Problems solved by technology

[0006] However, the etching solution using these peroxides has the following problems: i) the etching solution becomes unstable due to the peroxide content, and it may be difficult to supply it as a single solution; ii) the influence of Cu ions eluted during etching , to promote the decomposition of peroxides, and the life of the etching solution is short; iii) The peroxides accumulated in dead ends or waste liquids have the danger of explosion; iv) dry etching is prone to produce particles, and the yield rate is reduced. fixtures are expensive

However, in the method described in the same document, in order to adjust the etching rate of silver alloy and molybdenum, it is necessary to flow the etchant to meet appropriate conditions, and labor is required to adjust the conditions, and the etching rate under the flow condition of mixed acid is largely dependent on silver. material properties of alloys and molybdenum, so the method cannot be directly applied to other metal systems

[0012] In particular, an etchant combination for simultaneously etching a single film made of copper or a copper alloy and a multilayer film including two or more layers of the metal with an etchant composition containing phosphoric acid, nitric acid, and acetic acid has been reported. material and etching method (Patent Document 7), the layer as a "copper alloy" in the same document only discloses copper (I) oxide (CuO), and there is no specific description of alloys of copper and other metals in essence. , the same document does not describe the control of the taper angle, which is a very important element in microfabrication.

[0013] Furthermore, the film of copper (I) oxide (CuO) has a problem that the adhesion to the substrate is deteriorated because the oxide film is reduced due to the hydrogen plasma treatment performed in the TFT manufacturing process in the flat panel display manufacturing process.

For laminated films with copper and copper alloys, copper alloys are Cu-Mo, Cu-Ti, Cu-Ca, Cu-Mg, Cu-Ca-O, Cu-Mg-O, Cu-Al, Cu -Zr, Cu-Mn, Cu-NiB, Cu-Mn-B, Cu-Ni-B, Cu-Si, Cu-Al, Cu-Mo, Cu-Al, Cu-Mg-B, Cu-Ti-B , Cu-Mo-B, Cu-Al-B, Cu-Si-B, Cu-Mg-Al, Cu-Mg-Al-O and other laminated films, and further layers with copper and copper oxide (CuO) A large number of laminated films such as laminated films are candidates for next-generation films, but practically satisfactory films have not yet been achieved, and it is expected that the technology for fine pattern processing will be established soon

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