Etching solution for etching multilayer thin film comprising copper layer and titanium layer etching method using said solution and substrate obtained by using said method

Abstract

The invention provides an etching solution for etching a multilayer thin film overlapped on a substrate. The substate adopts more than one kind of glass, silicon dioxide and silicon nitride. The multilayer thin film contains a copper layer with a major component of copper and a titanium layer with a major component of titanium. An etching method of the multilayer thin film employing the copper layer and the titanium layer is provided. The substrate obtained by using the etching mode is provided. The etching solution, a water solution with PH value ranging from 1.5 to 2.5, contains (A) overprinting concentration 4.5 - 7.5 mass%; (B) Nitric acid concentration 0.8 to 6 mass%; (C) compound concentration 0.2 to 0.5 mass%; (D) general concentration 0.14 to 0.3 mass%; (E) specific Compound concentration 0.4 to 10% by mass; sum (F) overproduction Concentration concentration 0.005 to 0.1 mass%.

Description

technical field [0001] This technology relates to: an etchant for etching a multilayer thin film comprising a copper layer mainly composed of copper and titanium mainly composed of titanium, laminated on a glass, silicon dioxide or silicon nitride substrate layer; and an etching method using the same. The etchant of the present invention is particularly suitable for etching a multilayer film with a copper layer on a titanium layer. Background technique [0002] Conventionally, aluminum or aluminum alloys have generally been used as wiring materials for display devices such as flat panel displays. However, with the increase in size and resolution of displays, such aluminum-based wiring materials have a problem of signal delay due to characteristics such as wiring resistance, and uniform screen display tends to become difficult. [0003] Therefore, examples of using copper or metal wiring mainly composed of copper as a material with lower resistance are increasing. However,...

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Problems solved by technology

However, copper has the advantage of low resistance, but on the other hand, there are problems in that when copper is used for gate wiring, the adhesion between substrates such as glass and copper is not sufficient, and there are problems in the source / drain electrodes. When copper is used for electrode wiring, diffusion into the underlying organic silicon semiconductor film may occur

[0015] However, the etchant disclosed in Patent Documents 1 and 2 does not sufficiently satisfy the wiring shape after etching, and as a result, it may not be able to cope with an increase in the size and resolution of a display.

Furthermore, although Patent Document 2 contains acetic acid as an organic acid, it has the disadvantage that the dissolution of titanium is extremely slow (see Table 11 and Comparative Example 24).

[0016] In Patent Document 3, in order to etch molybdenum alloy and titanium, 0.01 to 1.0% by mass of a fluorine-containing compound is compounded, but fluorine corrodes glass, silicon dioxide or silicon nitride, which are often used as substrate bases, and as a result, changes in optical characteristics occur. and other adverse effects, therefore, it is desirable to have an etchant with little damage to glass, etc.

[0017] In addition, it is known in Patent Documents 1 to 3 that a relatively large amount of hydrogen peroxide is contained in the components (for example, 5.0 to 25% by mass in Patent Document 3), but it is dissolved in the etching solution due to repeated etching operations. The metal ions in the increase, the stability of hydrogen peroxide decreases

When the concentration of hydrogen peroxide in the etching solution decreases sharply, desired etching performance cannot be obtained, and the replenishment amount of hydrogen peroxide increases, which is economically disadvantageous.

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