JP2007067367A - Titanium/aluminum metal multilayer film etchant composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an etchant composition capable of etching a multilayer film in a batch without damaging a layer comprising titanium or an alloy using titanium as a principal component deposited on insulated substrates such as glasse, a silicon substrate and a compound semiconductor substrate by a sputtering method and a substrate of a ground using a metal multilayer containing aluminum or a layer comprising an alloy using aluminum as a principal component or the like and by suppressing a taper angle at 30-90°. <P>SOLUTION: The etchant composition comprising fluoride with a concentration (excluding hydrofluoric acid) of 0.01-5 mass% and a specified oxidizing agent with a concentration of 0.1-50 mass%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an etching solution composition for a metal laminated film used for gate, source and drain electrodes of a liquid crystal display.

  Aluminum or an alloy obtained by adding an impurity such as neodymium, silicon, or copper to aluminum is inexpensive and has a very low resistance. Therefore, it is used for a gate, source, and drain electrode material of a liquid crystal display.

  However, since aluminum or aluminum alloy has a slightly poor adhesion to the glass substrate as a base film and is easily corroded by chemicals or heat, a molybdenum or molybdenum alloy film is used above and / or below aluminum or aluminum alloy. The laminated film is used as an electrode material, and the laminated film is collectively etched with an etching solution using phosphoric acid or the like.

  In recent years, titanium or titanium alloys have been attracting attention for the purpose of increasing the price of molybdenum or molybdenum alloys and for further improving the corrosivity due to chemicals and heat. Phosphoric acid or the like for etching molybdenum cannot be used to etch titanium or titanium alloys. Reactive ion etching (RIE) using a halogen-based gas as a method for etching a titanium-aluminum metal laminated film on a semiconductor substrate is possible. ) Etc. are performed by dry etching. In RIE, the taper shape is controlled by anisotropic etching, but expensive vacuum equipment and high-frequency generators are required, which is disadvantageous in terms of cost. Development is desired.

On the other hand, when etching a metal thin film containing titanium as a main component in the manufacturing process of a semiconductor device, it is generally known to use a hydrofluoric acid-based etching solution (for example, Patent Document 1). It is also known that titanium or a titanium alloy can be etched with an etching solution using ammonia water-hydrogen peroxide water (for example, Patent Document 2).
However, when a hydrofluoric acid etching solution is used, it cannot be used because it damages the underlying glass substrate, silicon substrate, and compound semiconductor substrate. In addition, when ammonia water-hydrogen peroxide solution is used, bubbles are generated due to decomposition of the hydrogen peroxide solution, and etching is incomplete due to adhesion of the bubbles to the substrate, and it is difficult to use because the liquid life is short. It is.

In addition, the use is different from the present invention used as an etching solution for glass substrates and the like, but as an etching solution for the purpose of removing and smoothing the surface scale of titanium or titanium alloy used in decorative products and electronic parts, it is possible to peroxidize. Although a composition containing hydrogen, fluoride, inorganic acids, and a fluorosurfactant as essential components is disclosed (Patent Document 3), a layer made of titanium or a titanium-based alloy and aluminum or aluminum are mainly used. It does not teach etching of a metal laminated film including a layer made of an alloy as a component. Further, an aqueous solution containing peroxodisulfate and fluoride has been disclosed as an etchant for a metal laminate film composed of a titanium layer and a copper layer (Patent Document 4), but a metal laminate film composed of an aluminum layer and a titanium layer. Not about to etch.
Thus, a suitable means for etching the titanium-aluminum metal laminated film at a time has not been developed.

JP 59-124726 A JP-A-6-310492 JP 2004-43850 A JP 2001-59191 A

  That is, the subject of this invention is providing the etching liquid which can etch collectively the titanium-aluminum-type metal laminated film which solved the said problem.

In an intensive study to solve the above-mentioned problems, an etching solution in which a fluorine compound excluding hydrofluoric acid and an oxidizing agent are combined is composed of titanium or a titanium-based alloy layer and aluminum or aluminum as a main component. As a result of further research, the present inventors have completed the present invention.
That is, the present invention relates to an etching solution composition containing a fluorine compound (excluding hydrofluoric acid) and an oxidizing agent, comprising a layer made of titanium or a titanium-based alloy, and aluminum or aluminum as a main component. It is related with the said etching liquid composition used for batch-etching the metal laminated film containing the layer which consists of a component alloy.
Further, in the present invention, the fluorine compound is one or more selected from hexafluorosilicic acid and hydrofluoric acid or a salt of hexafluorosilicic acid and a metal or ammonia. Related to things.

  In the present invention, the oxidizing agent is nitric acid, ammonium nitrate, ammonium sulfate, ammonium peroxodisulfate, potassium peroxodisulfate, perchloric acid, ammonium perchlorate, sodium perchlorate, potassium perchlorate, periodic acid, periodic acid. It is related with the said etching liquid composition which is 1 type (s) or 2 or more types chosen from sodium acid, potassium periodate, methanesulfonic acid, hydrogen peroxide solution, sulfuric acid, and ethylenediamine sulfate.

The present invention relates to the etching solution composition, wherein the concentration of the fluorine compound is 0.01 to 5% by mass and the concentration of the oxidizing agent is 0.1 to 50% by mass.
The present invention also relates to the etching solution composition, wherein the oxidizing agent is nitric acid or methanesulfonic acid.
Furthermore, the present invention provides ammonium nitrate, ammonium sulfate, ammonium peroxodisulfate, potassium peroxodisulfate, perchloric acid, ammonium perchlorate, sodium perchlorate, potassium perchlorate, periodic acid, periodic acid as oxidizing agents. The present invention relates to the etching solution composition further comprising at least one selected from sodium, potassium periodate, hydrogen peroxide, sulfuric acid, and ethylenediamine sulfate.
The present invention also relates to the etching solution composition further comprising at least one selected from amidosulfuric acid, acetic acid and hydrochloric acid.

The present invention relates to the etching solution composition, wherein the base substrate is a glass substrate for liquid crystal display.
The present invention also relates to the etching solution composition, wherein the base substrate is a silicon substrate for a semiconductor device or a compound semiconductor substrate.
Further, according to the present invention, the taper angle after etching of a metal laminated film including a layer made of titanium or a titanium-based alloy and a layer made of aluminum or an alloy containing aluminum as a main component is set to 30 to 90 degrees. It is related with the said etching liquid composition used for performing.

  The etching solution of the present invention collectively forms a metal laminated film including a layer made of titanium or an alloy containing titanium as a main component and a layer made of aluminum or an alloy containing aluminum as a main component without adversely affecting the base substrate. Since it can be etched, it is particularly excellent in economic efficiency. In addition, since the taper angle can be easily controlled, high quality products can be manufactured by improving the coverage of the gate electrode.

  Hereinafter, embodiments of the present invention will be described in detail.

The gist of the etching solution composition of the present invention is that it is composed of a fluorine compound (excluding hydrofluoric acid), an oxidizing agent and water.
It is considered that the fluorine compound used in the etching solution of the present invention is mainly etched by dissolving titanium oxide on the metal laminated film oxidized by the oxidizing agent that is a component of the present etching solution. The fluorine compound used in the etching solution of the present invention may be any fluorine compound other than hydrofluoric acid, but hexafluorosilicic acid, hydrofluoric acid or hexafluorosilicic acid and metal or One or more selected from salts with ammonia, such as ammonium fluoride, potassium fluoride, calcium fluoride, ammonium hydrogen fluoride, potassium hydrogen fluoride, sodium fluoride, magnesium fluoride, Lithium fluoride, hexafluorosilicic acid, ammonium hexafluorosilicate, sodium hexafluorosilicate, and potassium hexafluorosilicate are preferable, and ammonium fluoride and ammonium hydrogen fluoride are particularly preferable.

Moreover, the oxidizing agent used in the etching solution of the present invention plays a role as an etching initiator by oxidizing titanium or a titanium alloy on the metal laminated film. The oxidizing agent used in the etching solution of the present invention is nitric acid, ammonium nitrate, ammonium sulfate, ammonium peroxodisulfate, potassium peroxodisulfate, perchloric acid, ammonium perchlorate, sodium perchlorate, potassium perchlorate, periodate. One or more selected from acids, sodium periodate, potassium periodate, methanesulfonic acid, hydrogen peroxide, sulfuric acid and ethylenediamine sulfate, of which nitric acid, ammonium peroxodisulfate, methanesulfone Acid is preferred.
Nitrogen-containing organic compound sulfates other than ammonium sulfate and ethylenediamine sulfate, for example, sulfates such as piperazine, 1- (2-aminoethyl) piperazine, 1-amino-methylpiperazine can also be used as oxidizing agents. Ethylenediamine sulfate is preferred.
Nitric acid or methanesulfonic acid is particularly preferable because the taper angle is low even at low concentrations, for example, 40 degrees or less. Oxidizing agents other than nitric acid and methanesulfonic acid are preferable because the effect of reducing the taper angle is low, but damage to the resist is small and the amount of side etching can be controlled. The etching solution containing the fluorine compound and nitric acid or methanesulfonic acid can control the taper angle to 40 degrees or less, and further from an oxidizing agent other than nitric acid and methanesulfonic acid, or amidosulfuric acid, acetic acid, hydrochloric acid. By adding at least one selected from the above, the taper angle can be controlled between 30 and 90 degrees.
Preferred combinations for the etching solution composition of the present invention include ammonium fluoride and nitric acid, ammonium fluoride and methanesulfonic acid, and combinations using two or more oxidizing agents, such as ammonium fluoride, nitric acid and perchloric acid, Ammonium fluoride and nitric acid and sulfuric acid, ammonium fluoride and nitric acid, perchloric acid and methanesulfonic acid, ammonium fluoride and nitric acid, perchloric acid and sulfuric acid are preferred.
Further, for the purpose of improving the wettability with the substrate, a surfactant or an organic solvent that is generally used may be added to the present etching solution.

  The etching solution of the present invention mainly comprises a layer made of titanium or a titanium-based alloy formed on a silicon substrate or a compound semiconductor substrate on an insulating substrate made of a glass substrate or the like, and aluminum or aluminum. Suitable for etching a metal laminated film including a layer made of an alloy as a component, for example, a metal laminated film made of titanium / aluminum, aluminum / titanium, titanium / aluminum / titanium, and a fluorine compound of the etching solution The concentration is 0.01 to 5% by mass, preferably 0.1 to 1% by mass, and the concentration of the oxidizing agent is 0.1 to 50% by mass, preferably 0.5 to 10% by mass.

When the fluorine compound concentration is lower than 5% by mass, the underlying glass is not damaged and includes a layer made of titanium or an alloy containing titanium as a main component and a layer made of aluminum or an alloy containing aluminum as a main component. When the side etching amount of the metal laminated film is suppressed and is higher than 0.01% by mass, the etching unevenness of titanium or the titanium alloy is reduced, and the shape after etching becomes good. When the content of the oxidizing agent is lower than 50% by mass, the side etching amount of the metal laminated film including the layer made of titanium or an alloy containing titanium as a main component and the layer made of aluminum or an alloy containing aluminum as a main component is suppressed. In addition, when the resist is not damaged and is higher than 0.1% by mass, the etching rate of titanium or a titanium alloy is fast and efficient.
Further, in order to appropriately control the taper angle, particularly in order to set it to 30 to 90 degrees, nitric acid or methanesulfonic acid and another oxidizing agent are used alone or in appropriate combination. In this case, nitric acid or methanesulfonic acid is preferably 0.1 to 30% by mass, particularly preferably 0.5 to 15% by mass, and the other oxidizing agent is 0.1 to 20% by mass, particularly 0.5%. It is preferable to set it as -15 mass%.
In particular, nitric acid or methanesulfonic acid is preferably used in order to make the taper angle 40 degrees or less.
Moreover, when at least 1 sort (s) chosen from an amide sulfuric acid, an acetic acid, or hydrochloric acid is further included, these density | concentrations are 0.01-10 mass%, Especially 0.5-5 mass% is preferable.

The base substrate of the metal laminate film etched by the etching solution of the present invention is not particularly limited, but when a titanium or aluminum metal laminate film is used for a liquid crystal display, a glass substrate is preferable, and when used for a semiconductor device, A silicon substrate and a compound semiconductor substrate are preferred.
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1-25
As shown in FIG. 1, a substrate in which titanium (700 mm) / aluminum (2500 mm) / titanium (200 mm) was formed on a glass substrate (1) by sputtering was prepared.
Next, it patterned using the resist (4) on the titanium / aluminum / titanium metal laminated film, and was immersed in the etching liquid of Examples 1-25 of Table 1 (etching temperature 30 degreeC). Thereafter, the substrate was washed with ultrapure water, dried with nitrogen blow, and the substrate shape was observed with an electron microscope. The results are shown in Table 1.

Comparative Examples 1-2
Titanium / aluminum / titanium formed by sputtering on the glass substrate used in the examples was immersed in an etching solution composed of each component of Comparative Examples 1 and 2 in Table 1 and processed in the same manner as in the examples. . The results are also shown in Table 1.

  As apparent from Table 1, by etching using the etching solution of the present invention, the titanium / aluminum / titanium laminated film formed by the sputtering method could be collectively etched in a short time.

  The etching solution of the present invention can be used as an etching solution for a metal laminate film in forming a wiring or an electrode in a manufacturing process of an electronic device such as a semiconductor device or a liquid crystal display.

The wiring process of the metal laminated film formed on the insulating substrate and including a layer made of titanium or an alloy containing titanium as a main component and a layer made of aluminum or an alloy containing aluminum as a main component is shown.

Explanation of symbols

(1) Glass substrate (2) Titanium or titanium alloy film (3) Aluminum or aluminum alloy film (4) Resist (a) Gate electrode after etching with the etching solution of the present invention (substantially uniform taper shape and 40 degrees The following taper shape)
(B) Source or drain electrode after etching with the etching solution of the present invention (taper angle of 90 degrees)

Claims (10)

  An etchant composition containing a fluorine compound (excluding hydrofluoric acid) and an oxidizing agent, wherein the layer is made of titanium or a titanium-based alloy and the layer is made of aluminum or an aluminum-based alloy The said etching liquid composition used for collectively etching the metal laminated film containing these.   The etching solution composition according to claim 1, wherein the fluorine compound is one or more selected from hexafluorosilicic acid and a salt of hydrofluoric acid or hexafluorosilicic acid with a metal or ammonia.   The oxidizing agent is nitric acid, ammonium nitrate, ammonium sulfate, ammonium peroxodisulfate, potassium peroxodisulfate, perchloric acid, ammonium perchlorate, sodium perchlorate, potassium perchlorate, periodic acid, sodium periodate, The etching liquid composition of Claim 1 or 2 which is 1 type, or 2 or more types chosen from potassium iodate, methanesulfonic acid, hydrogen peroxide solution, a sulfuric acid, and ethylenediamine sulfate.   The etching liquid composition in any one of Claims 1-3 whose density | concentration of a fluorine compound is 0.01-5 mass% and whose density | concentration of an oxidizing agent is 0.1-50 mass%.   The etching liquid composition in any one of Claims 1-4 whose oxidizing agent is nitric acid or methanesulfonic acid.   As an oxidizing agent, ammonium nitrate, ammonium sulfate, ammonium peroxodisulfate, potassium peroxodisulfate, perchloric acid, ammonium perchlorate, sodium perchlorate, potassium perchlorate, periodic acid, sodium periodate, periodate The etching solution composition according to claim 5, further comprising at least one selected from potassium acid, aqueous hydrogen peroxide, sulfuric acid, and ethylenediamine sulfate.   The etching solution composition according to claim 1, further comprising at least one selected from amidosulfuric acid, acetic acid, and hydrochloric acid.   The etching liquid composition in any one of Claims 1-7 whose base substrate is a glass substrate for liquid crystal displays.   The etching solution composition according to claim 1, wherein the base substrate is a silicon substrate for a semiconductor device or a compound semiconductor substrate.   Used for setting the taper angle after etching of a metal laminated film including titanium or a layer made of titanium as a main component and a layer made of aluminum or an alloy containing aluminum as a main component to 30 to 90 degrees. The etching liquid composition in any one of Claims 1-9.

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