KR20150105038A - Multi-layer etching solution composition for formation of metal line - Google Patents

Abstract

The present invention relates to a multi-layer etching solution composition for forming a metal line. More specifically, the present invention comprises: 60-70 wt% of phosphoric acid; 2-8 wt% of nitric acid; 5-15 wt% of acetic acid; 0.1-7 wt% of at least one potassium based compound selected in a group composed of K3PO4, K2HPO4, KH2PO4, CH3CO2K, and KNO3; 0.1-5 wt% of alkyl (1-5 of carbon number) tetrazole; and the remainder being water. Therefore, the present invention is capable of etching multiple layers composed of an aluminum based metal film and the molybdenum based metal film in a micro-line width.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-layer etchant composition for metal wiring formation,

The present invention relates to a multilayer film etchant composition for metal wiring formation.

A transparent pixel electrode, a gate electrode, a source electrode, and a drain electrode are used in a TFT (Thin Film Transistor) array for image implementation of a flat panel display. In general, a transparent conductive film containing indium as a main component is used as a pixel electrode, and a single film or a multi-film is used as a gate electrode, a source electrode, and a drain electrode mainly composed of Cr, Cu, Mo, Ti, and Al.

In recent years, indium tin oxide (ITO or amorphous ITO) has been deposited as an indium-based transparent conductive film at the lowermost part by a gate wiring in order to simplify the production process and increase the production amount. The upper and lower portions are made of a molybdenum- Layered film is deposited on the gate insulating film and a gate wiring having a total of fourteen film structures is being developed. In the data wiring, an indium zinc oxide (IZO) thin film containing indium as a main component is deposited on the upper layer, and a three-layer film consisting of an upper metal part of molybdenum metal film and an aluminum- A new data wiring structure is being developed. At this time, in order to etch the gate wiring, the bottom indium tin oxide thin film should not be etched, but only the three-layer film (the upper and lower molybdenum metal film and the intermediate aluminum metal film) should be selectively etched in a batch. On the other hand, in the case of the data wiring, the IZO thin film composed mainly of indium as the main component and the triple layer film (upper and lower molybdenum-based metal film and intermediate-layer aluminum-based metal film) Has been demanded.

In the case of a multi-layered film made of a conventional aluminum-based metal film and a molybdenum-based metal film, the film can usually be etched with a phosphoric acid-based aluminum etchant. However, when a quaternary film in which an IZO thin film mainly composed of indium is deposited, and a three-layer film in which a molybdenum-based metal film is disposed on the lower side and an aluminum-based metal film is laminated on the lower side is etched with a conventional phosphoric acid- IZO, which is an indium-based transparent conductive film, has a lower profile than an underlying molybdenum-based metal film and an aluminum-based metal film, so that the upper IZO thin film protrudes from the etched surface, resulting in a poor profile. Because of the profile with such a large tip defect, the step coverage becomes poor in the subsequent process, and the probability that the upper layer is disconnected at the inclined plane or the upper and lower metal is short-circuited becomes large.

On the other hand, the recent miniaturization and integration of circuits are becoming more and more important, and the production of fine patterns has become a subject of major research. Therefore, an etchant capable of forming a fine pattern is also required.

Therefore, in order to efficiently etch the multilayer film efficiently, an etchant having an excellent etching property for an aluminum-based metal film and a molybdenum-based metal film is required, and an etchant capable of forming a fine pattern must be developed at the same time.

Korean Patent Laid-Open Publication No. 2002-0043402 discloses an etching technique using mixed acid of phosphoric acid, nitric acid, and acetic acid to etch various multilayer films, but it has poor S / E characteristics And is not suitable for the formation of fine patterns.

Korean Patent Publication No. 2002-0043402

An object of the present invention is to provide an etchant composition having a small side etching amount so that a fine pattern can be formed.

An object of the present invention is to provide an etchant composition suitable for batch etching of an aluminum-based metal film and a molybdenum-based metal film structure applied to a fine pattern of a thin film transistor array applicable to high resolution.

1. 60 to 70% by weight of phosphoric acid; 2 to 8% by weight of nitric acid; 5 to 15% by weight of acetic acid; 0.1 to 7% by weight of at least one potassium-based compound selected from the group consisting of K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CH ₃ CO ₂ K and KNO ₃ ; 0.1 to 5% by weight of an alkyl (C 1-5) tetrazole; And an amount of water, wherein the etching solution composition comprises an IZO transparent conductive film, an aluminum-based metal film, and a molybdenum-based metal film.

2. The method of claim 1, wherein the potassium-based compound is a mixture of KNO ₃ and at least one compound selected from the group consisting of K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ and CH ₃ CO ₂ K, IZO A transparent conductive film, an aluminum-based metal film, and a molybdenum-based metal film.

3. The etchant composition according to item 1, wherein the alkyltetrazole is at least one selected from methyltetrazole and ethyltetrazole, the IZO transparent conductive film, the aluminum-based metal film, and the molybdenum-based metal film.

4. The multilayer film etchant composition as defined in 1 above, further comprising a sulfuric acid or a sulfate compound, the multilayer film comprising an IZO transparent conductive film, an aluminum-based metal film, and a molybdenum-based metal film.

5. An indium tin oxide-based transparent conductive film, a metal film for gate wiring formed by depositing a three-layer film having upper and lower portions made of a molybdenum-based metal film and an intermediate layer made of an aluminum- And a step of laminating a three-layer film comprising a molybdenum-based metal film on the upper and lower sides and an aluminum-based metal film on the lower side of the transparent base film and etching the metal film for the data wiring, In the method of manufacturing,

And etching the metal film for a gate wiring and the metal film for a data wiring with an etching solution according to any one of 1 to 4 above.

6. A method for manufacturing a transparent conductive film, comprising the steps of: a) depositing a three-layered film of an indium tin oxide-based transparent conductive film, an upper and a lower molybdenum-based metal film thereon and an aluminum- Forming an upper indium tin oxide based transparent conductive film by etching the upper three layers of the transparent conductive film without etching; And

b) a three-layer film in which the upper and lower portions are made of a molybdenum-based metal film and the intermediate layer is made of an aluminum-based metal film, and an indium zinc oxide-based transparent conductive film is laminated thereon to form a metal film having a total structure of four- To form a data wiring. ≪ RTI ID = 0.0 > 21. < / RTI >

The etching solution composition of the present invention is capable of forming a fine pattern with a small amount of side etching, and particularly, the side etching of the aluminum-based metal film and the molybdenum-based metal film is small.

The aluminum-based metal film and the molybdenum-based metal film used for the thin film transistor array used in the high-resolution image display apparatus are thicker than the conventional aluminum-based metal film to a thickness of about 10,000 angstroms. But also shows a small side etching amount.

Therefore, when the etching solution composition of the present invention is used, the etching process is significantly simplified, so that a fine pattern can be produced with high productivity.

The present invention relates to a composition comprising 60 to 70% by weight of phosphoric acid; 2 to 8% by weight of nitric acid; 5 to 15% by weight of acetic acid; 0.1 to 7% by weight of at least one potassium-based compound selected from the group consisting of K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CH ₃ CO ₂ K and KNO ₃ ; 0.1 to 5% by weight of an alkyl (C 1-5) tetrazole; And water in a remaining amount to etch the multilayered film composed of the aluminum-based metal film and the molybdenum-based metal film with a fine line width.

Hereinafter, the present invention will be described in more detail.

In the present invention, the indium-based transparent conductive film is used as a pixel electrode, and means a transparent conductive film containing indium as a main component. Specifically, it includes indium zinc oxide (IZO), indium tin oxide (ITO, a-ITO) Indium oxide film. In the phosphorus-based main etchant of the present invention, the etching selectivity of IZO and the indium tin oxide film is very high, so that the indium tin oxide film in the gate wiring is not etched within the processing time because the etching rate is very slow. However, Since the etch rate is higher than that of the oxide film, it is possible to perform a batch etching in a multilayer structure of Mo and Al. In this regard, the present invention is described in Korean Patent Publication No. 2013-68579, which is hereby incorporated by reference in its entirety.

In the present invention, the aluminum-based metal film means an aluminum film or aluminum alloy film containing aluminum as a main component. The aluminum-based alloy film is made of Al-X (X is La, Mg, Zn, In, Ca, Te, Sr, Cr, Co, Mo, Nb, Ta, W, Ni, , Si, Ti, Pt, and C) alloy film may be used. When an Al-X alloy film is used as the aluminum-based metal film, there is an advantage that a process problem due to the occurrence of a Hillock phenomenon due to heat of aluminum can be avoided.

In the present invention, the molybdenum-based metal film means a molybdenum film or a molybdenum alloy film containing molybdenum as a main component which acts as a buffer against a cell reaction between thin films. The molybdenum alloy film is formed, for example, by alloying at least one metal selected from metal groups of Ti, Ta, Cr, Ni, Nd, In and Al as a main component of molybdenum alloy film.

In the present invention, the multilayered film means that a transparent conductive film of indium tin oxide is formed in the lower layer in the case of gate wiring, and is formed of a quaternary film in which a molybdenum-based metal film, an aluminum-based metal film, and a molybdenum- In the case of the data wiring, it means that the IZO transparent conductive film is formed on the upper layer and composed of a molybdenum-based metal film, an aluminum-based metal film, and a molybdenum-based metal film in this order.

The etchant composition of the present invention includes phosphoric acid, nitric acid, acetic acid, potassium-based compounds, alkyltetrazole, and water.

The phosphoric acid serves to oxidize the aluminum-based metal film and the molybdenum-based metal film and is contained in an amount of 60 to 70% by weight based on the total weight of the composition. When the phosphoric acid content is less than 60% by weight, the etching rate of the aluminum-based metal film or the molybdenum-based metal film is lowered and there is a risk of residue, and when the phosphoric acid content is 70% or more, the etching rate of the aluminum-based metal film and the molybdenum- The etching rate of the IZO transparent conductive film is slowed down and the occurrence of the tip may appear to be large.

The nitric acid serves to oxidize the surfaces of the IZO transparent conductive film, the aluminum-based metal film and the molybdenum-based metal film, and is contained in an amount of 2 to 8% by weight based on the total weight of the composition. When the content of nitric acid is less than 2% by weight, the etching rate of the aluminum-based metal film and the molybdenum-based metal film is lowered. Such a phenomenon causes a difference in the etching rate depending on positions in the substrate, . When the amount of the nitric acid is more than 8 wt%, cracks are generated in the photoresist, and thus the aluminum-based metal film and the molybdenum-based metal film may be short-circuited due to the penetration of the chemical solution. There is a fear that the metal wiring may lose its function due to the disappearance of the metal film and the molybdenum-based metal film.

The nitric acid is a component for oxidizing the surface of the IZO transparent conductive film, the aluminum-based metal film and the molybdenum-based metal film, and is contained in an amount of 5 to 15% by weight based on the total weight of the composition. If the amount of the acetic acid is less than 5 wt%, the IZO transparent conductive film, the aluminum-based metal film, and the molybdenum-based metal film are not etched smoothly, and aluminum and molybdenum residues may partially be formed in the substrate. If the amount of the acetic acid is more than 15% by weight, the over-etching angle between molybdenum and aluminum is not obtained and uniform etching characteristics can not be obtained.

The potassium salt compound is at least one compound selected from the group consisting of K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CH ₃ CO ₂ K and KNO _{3. The} potassium salt compound is a compound of an oxidized aluminum-based metal film and a molybdenum- It serves to control the etching profile and is contained in an amount of 0.1 to 7% by weight, more preferably 1 to 5% by weight based on the total weight of the composition. When the potassium salt compound is contained in an amount less than 0.1% by weight, the etching rate of the molybdenum-based metal film is relatively fast, so that the IZO Tip can be very large in the data wiring. When the potassium compound exceeds 7% by weight, And the etching rate of the molybdenum-based metal film may be very slow, so that the residual film of the aluminum-based metal film and the molybdenum-based metal film may remain.

The potassium-based compound is preferably used by mixing two components, and at least one compound selected from the group consisting of K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO _4, and CH ₃ CO ₂ K and KNO ₃ It is more preferable to use a mixture. In this case, it is preferable that KNO ₃ and the remaining components are mixed in a weight ratio of 1: 3 to 3: 1.

The alkyl (C 1 to C 5) tetrazole is a component that slows the lateral etching rate of the aluminum-based metal film and the molybdenum-based metal film. Since the longitudinal etching rate is not slowed down, So that it is possible to form a fine pattern by adjusting only the lateral etching rate relatively.

The alkyltetrazole is contained in an amount of 0.1 to 5% by weight, more preferably 1 to 5% by weight, based on the total weight of the composition. When the content is less than 0.1% by weight, side etching becomes large and formation of a fine pattern is difficult. When the content is more than 5% by weight, etching may not proceed sufficiently and residues may be generated.

The alkyltetrazole is preferably at least one of methyltetrazole and ethyltetrazole.

As the water contained in the etchant composition of the present invention, it is preferable to use deionized water, and it is preferable that the deionized water is used at a level of 18 M OMEGA. Or more for semiconductor processing.

If necessary, in addition to the above-mentioned components, the etching solution composition of the present invention may further include a sulfuric acid or sulfate compound as an etching control agent to control the type of IZO which is an indium-based transparent conductive film. The sulfuric acid or sulfate compound means a compound capable of being dissociated into sulfate ion and specifically includes sulfuric acid and is exemplified by ammonium sulfate, potassium sulfate, calcium sulfate, sodium sulfate, paratoluenesulfonic acid (PTSA), sulfonic acid such as methanesulfonic acid , And they may be used singly or in combination of two or more. The sulfuric acid or sulfate compound may preferably be contained in an amount of 0.1 to 5% by weight based on the total weight of the composition.

The etchant of the present invention may further comprise at least one of a surfactant, a sequestering agent, a corrosion inhibitor and a pH adjuster in addition to the above components.

The present invention also relates to a metal film for a gate wiring made of an indium tin oxide type transparent conductive film, a metal film for a gate wiring formed by depositing a three-layer film having an upper and a lower molybdenum metal film as its upper and lower parts and an aluminum- And a step of laminating a three-layer film having a zinc oxide-based transparent conductive film and a lower portion thereof made of a molybdenum-based metal film and an intermediate layer made of an aluminum-based metal film, and etching the metal wiring for a data wiring, A method of manufacturing a transistor includes the step of etching with the etching solution of the present invention as described above.

In the case of manufacturing the thin film transistor by etching the gate wiring and the data wiring with the etching solution composition of the present invention, the gate wiring and the data wiring can be etched with a fine line width. In particular, even if the aluminum-based metal film has a thick film structure of about 10,000 angstroms, the gate wiring and the data wiring can be formed with a fine line width by performing uniform and small side etching.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

Example

An etching solution composition was prepared in the composition shown in Table 1 below (unit: wt%).

Phosphoric acid nitric acid Acetic acid Potassium monophosphate Potassium nitrate Azole compound Deionized water Kinds content Example 1 66 5 10 3 One MTZ One Balance Example 2 66 5 10 3 One ETZ One Balance Comparative Example 1 66 5 10 3 One - - Balance Comparative Example 2 66 5 10 3 One ATZ One Balance Comparative Example 3 66 5 10 3 One BTA One Balance MTZ: methyl tetrazole
ETZ: ethyl tetrazole
ATZ: Aminotetrazole
BTA: benzotriazole

Test Example

As a test substrate, a triple layer of Mo / Al / Mo was deposited on the glass and the photoresist was patterned in a certain shape. At this time, the layer thickness of Mo / Al / Mo was 300 Å / 10,000 Å / 700 Å.

The etchant prepared in the above Examples and Comparative Examples was placed in an experimental apparatus (SEMES, model name: ETCHER (TFT)) of a spray-type etch system, the temperature was set at 40 ° C and the temperature reached 40 ± 0.1 ° C After that, an etching process was performed. Total etch time was 50% of EPD compared to gate substrate and 100% of EPD was applied to data substrate. When the etching was completed, the specimen was injected. After the etching was completed, the substrate was rinsed with deionized water, dried using a hot air drying apparatus, and photoresist was removed using a photoresist (PR) stripper. After cleaning and drying, the inclination angle (T / A) and the side etching amount of the etching profile were measured using an electron microscope (SEM: model name: S-4700, manufactured by Hitachi, Ltd.). The results are shown in Table 2 below.

[Evaluation Criteria of Etching Profile]

Good: Excellent (T / A: 60 ° or more and less than 70 °)

?: Good (T / A: 40 ° or more to less than 60 °)

X: poor (T / A: <40 °,> 70 ° or metal film loss and residue generation)

Types of Thin Films Side etching
(um) T / A Example 1 Mo / Al / Mo 0.99 63.6 °, ○ Example 2 1.06 65.6 °, ○ Comparative Example 1 1.27 69.0 °, O Comparative Example 2 1.22 58.7 [deg.], [Delta] Comparative Example 3 1.28 59.1 [deg.], [Delta]

Referring to Table 2, it can be seen that the etching solution composition of the embodiments of the present invention has significantly less side etching amount than the comparative examples and has an excellent etching profile.

Claims (6)

60 to 70% by weight of phosphoric acid;
2 to 8% by weight of nitric acid; 5 to 15% by weight of acetic acid;
0.1 to 7% by weight of at least one potassium-based compound selected from the group consisting of K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ , CH ₃ CO ₂ K and KNO ₃ ;
0.1 to 5% by weight of an alkyl (C 1-5) tetrazole; And
Layer film composed of an IZO transparent conductive film, an aluminum-based metal film, and a molybdenum-based metal film, the water comprising a residual amount of water.
The method of claim 1, wherein the potassium-based compound is a mixture of KNO ₃ and at least one compound selected from the group consisting of K ₃ PO ₄ , K ₂ HPO ₄ , KH ₂ PO ₄ and CH ₃ CO ₂ K, Film, an aluminum-based metal film, and a molybdenum-based metal film.
The etchant composition according to claim 1, wherein the alkyltetrazole is at least one selected from methyltetrazole and ethyltetrazole, the IZO transparent conductive film, the aluminum-based metal film, and the molybdenum-based metal film.
The etchant composition according to claim 1, further comprising a sulfuric acid or a sulfate compound, the multilayer film comprising an IZO transparent conductive film, an aluminum-based metal film, and a molybdenum-based metal film.
An indium tin oxide-based transparent conductive film, a metal film for a gate wiring made of a total of fourteen film structures by depositing a three-layer film having upper and lower parts made of a molybdenum-based metal film and an intermediate layer made of an aluminum- And a step of laminating a three-layer film having a molybdenum-based metal film on its upper and lower portions and an aluminum-based metal film on the conductive film and a lower portion thereof, and etching the metal film for data wiring having a total of fourteen membrane structures In the method,
And etching the metal film for a gate wiring and the metal film for a data wiring with the etching solution according to any one of claims 1 to 4. A method for manufacturing a thin film transistor,
a) a three-layered film of an indium tin oxide-based transparent conductive film, an upper and a lower molybdenum-based metal film on the upper and lower surfaces thereof, and an aluminum-based metal film as an intermediate layer are deposited to form a metal film of a total of fourteen- The bottom indium tin oxide type transparent conductive film is formed by etching the three-layer film in an upper portion without etching, thereby forming a gate wiring; And
b) a three-layer film in which the upper and lower portions are made of a molybdenum-based metal film and the intermediate layer is made of an aluminum-based metal film, and an indium zinc oxide-based transparent conductive film is laminated thereon to form a metal film constituted of a total of four- To form a data wiring. &Lt; RTI ID = 0.0 &gt; 21. &lt; / RTI &gt;