KR20080051249A - Etchant composition for multi layers thin film comprising titanium or titanium alloy layer, and aluminum or aluminum alloy layer - Google Patents

Abstract

An etchant composition for etching a metal film formed from a multilayer film comprising a titanium or titanium alloy layer and an aluminum or aluminum alloy layer is provided, wherein the etchant composition has a fast etching speed, does not damage a bottom layer or equipment, does not require expensive equipment, is advantageous in large products such as LCD panels, and obtain excellent productivity due to uniform etching properties. An etchant composition for a multilayer film comprising a titanium or titanium alloy layer and an aluminum or aluminum alloy layer comprises 1 to 20 wt.% of HNO3, 0.1 to 10 wt.% of H2SO4, 0.01 to 5 wt.% of NH4F.HF, and the balance of water based on the total composition weight. The etchant composition comprises 5 to 15 wt.% of HNO3, 0.1 to 5 wt.% of H2SO4, and 0.01 to 3 wt.% of NH4F.HF based on the total composition weight. The multilayer film comprising a titanium or titanium alloy layer and an aluminum or aluminum alloy layer is a multi-metal film of a double layer in which the titanium or titanium alloy layer is laid up on a top or bottom part of the aluminum or aluminum alloy layer, or a triple or higher layer in which the titanium or titanium alloy layer and the aluminum or aluminum alloy layer are alternately laid up.

Description

ETCHANT COMPOSITION FOR MULTI LAYERS THIN FILM COMPRISING TITANIUM OR TITANIUM ALLOY LAYER, AND ALUMINUM OR ALUMINUM ALLOY LAYER}

1 is a SEM image showing the etching state of the Ti / Al / Ti triple layer by the etchant of Example 2 of the present invention.

FIG. 2 is an SEM image showing the etching state of the Ti / Al / Ti triple layer by the etchant of Example 5 of the present invention.

FIG. 3 is an SEM image showing the etching state of the Ti / Al / Ti triple layer by the etchant of Example 7 of the present invention.

4 is an SEM image showing the etching state of the Ti / Al / Ti triple layer by the etchant of Comparative Example 1 of the present invention.

FIG. 5 is an SEM image showing the etching state of the Ti / Al / Ti triple layer by the etchant of Comparative Example 3 of the present invention.

The present invention can wet-etch a metal film formed of a multilayer film including a titanium or titanium alloy film, and an aluminum or aluminum alloy film, among metals used in a gate, a source / drain electrode, of a liquid crystal display. The present invention relates to an etchant composition.

In the liquid crystal display device, the process of forming the metal wiring on the substrate is generally composed of a metal film forming process by sputtering, a photoresist forming process in a selective region by photoresist coating, exposure and development, and an etching process. And washing steps before and after the individual unit steps. The etching process refers to a process of leaving a metal film in a selective region using a photoresist mask, and typically, a dry etching using a plasma or the like, or a wet etching using an etching solution is used.

During the construction of the liquid crystal display, the metal layer uses Al having a low resistance as the conductive layer, and the aluminum layer is a short-circuit with other conductive layers by hillock and an insulating layer by contact with the oxide layer in a subsequent process. There is a problem of formation. As a buffer layer, Mo, Ti, Cr, and alloys containing these as main components are used as the buffer layer, and recently, Ti having corrosion resistance, robustness, and high strength has been spotlighted.

Electrode in which the Ti layer is used as a buffer layer has been conventionally etched using halogen gas in a dry etching process, but has an anisotropic profile and superior etching control power compared to a wet etching process. There is a difficulty in constructing the composition and the large area, and there is a problem that productivity is lowered because the etching speed is slow.

Accordingly, Korean Patent Application Nos. 10-1999-0005010, 10-1999-0043017, and the like disclose the use of HF as one component of an etchant composition for wet etching a Ti layer.

However, when HF is used for wet etching, a lot of constraints are placed on the process conditions due to damage to the underlying film and the equipment, which causes a decrease in productivity.

As a result of intensive efforts to solve the problems of the prior art as described above, the present inventors have developed an etching solution composition having a new characteristic to complete the present invention.

Therefore, in the present invention, in etching a metal film formed of a titanium or titanium alloy film, and a multilayer film including an aluminum or aluminum alloy film, the etching speed is high, there is no damage to the underlying film and the equipment, and no expensive equipment configuration is required. It is an object of the present invention to provide an etching liquid composition having an excellent productivity because it is advantageous for large area, and has uniform etching characteristics.

In order to achieve the above object, the present invention is 1 to 20% by weight of HNO ₃ , 0.1 to 10% by weight of H ₂ SO ₄ , 0.01 to 5% by weight of NH ₄ F.HF, and the balance relative to the total weight of the composition A multilayer film etching liquid composition comprising a titanium or titanium alloy film containing water, and an aluminum or aluminum alloy film is provided.

In the above, the etchant composition of the present invention, 5 to 15% by weight of HNO ₃ , 0.1 to 5% by weight of H ₂ SO ₄ , 0.01 to 3% by weight of NH ₄ F.HF, and the residual amount of water based on the total weight of the composition More preferably.

The etchant composition of the present invention is applied to a multilayer film including a titanium or titanium alloy film, and an aluminum or aluminum alloy film, wherein the multilayer film includes a double film in which a titanium or titanium alloy film is laminated on or below an aluminum or aluminum alloy film. In addition, for example, a titanium or titanium alloy film and a multilayer or more multiple metal film in which an aluminum or aluminum alloy film is alternately stacked are included.

In particular, the etchant composition of the present invention can be preferably used in a triple layer made of a titanium or titanium alloy film in the upper layer, an aluminum or aluminum alloy film in the middle layer, and a titanium or titanium alloy film in the lower layer.

The titanium or titanium alloy film is a concept including a metal film made of Ti as a main component and an alloy using another metal according to the characteristics of the Ti film or the film, and the aluminum or aluminum alloy film is Al according to the properties of the Al film or film. The concept includes a metal film made of an alloy by using a main component and another metal.

In the compositions of the present invention, HNO ₃ , H ₂ SO ₄ , and NH ₄ F.HF can be prepared according to commonly known methods, and it is particularly desirable to have a purity for semiconductor processing.

In the present invention, HNO ₃ oxidizes Ti and Al as a component used as the main oxidizing agent, preferably 1 to 20% by weight based on the total weight of the composition, when HNO ₃ is contained in less than 1% by weight of Al And a problem of lowering the etch rate of the Al alloy layer and the failure of the etch profile, and when exceeding 20 wt%, lifting and cracking of the photoresist occurs, and side etch is controlled (side Large etch and very low taper angle).

In the present invention, H ₂ SO ₄ oxidizes Ti and Al as a component used as the main oxidizing agent, it is preferably contained in 0.1 to 10% by weight relative to the total weight of the composition. When H ₂ SO ₄ is contained in less than 0.1% by weight, the undercut of the upper and lower Ti and Ti alloy layers deepens, which may cause staining in the substrate, and when it exceeds 10% by weight, Al And disadvantages in that the etch rate of the Al alloy layer is lowered.

In the present invention, NH ₄ F.HF serves to etch the oxidized surface of the metal or metal alloy by the main oxidizing agents, it is preferably contained in 0.01% by weight to 5% by weight relative to the total weight of the composition. When NH ₄ F · HF is contained in less than 0.01% by weight, the etch rate of the Ti and Ti alloy layers is lowered, causing an etch deviation in the substrate, resulting in a problem of staining, and exceeding 5% by weight. In this case, there is a disadvantage in the underlayer attack.

The etchant composition of the present invention may include an additive commonly used in the etchant composition in addition to the above composition.

The etchant composition of the present invention has a characteristic that does not cause a problem of damage to the underlying film and equipment by the etchant by using NH ₄ F. HF instead of the conventionally used HF.

Hereinafter, the present invention will be described in more detail with reference to Examples and Test Examples. However, the scope of the present invention is not limited by the following examples and test examples.

Example  1-9 and Comparative example  1-5: Etchant  Preparation of the composition

According to the component and the composition ratio shown in Table 1 was prepared so that the etching solution composition is 180 kg.

HNO ₃ H ₂ SO ₄ NH ₄ F · HF HF water Example 1 7 0.1 0.1 Remaining amount Example 2 7 0.5 0.1 Remaining amount Example 3 7 2 0.1 Remaining amount Example 4 5 0.5 0.1 Remaining amount Example 5 9 0.5 0.1 Remaining amount Example 6 15 0.5 0.1 Remaining amount Example 7 9 One 0.1 Remaining amount Example 8 9 One 1.0 Remaining amount Example 9 9 One 3.0 Remaining amount Comparative Example 1 7 0 0.1 Remaining amount Comparative Example 2 25 5 One Remaining amount Comparative Example 3 10 15 One Remaining amount Comparative Example 4 10 5 One Remaining amount Comparative Example 5 10 5 7 Remaining amount

(Unit: weight%)

Test Example  One

A SiNx layer is deposited on the glass, and a Ti / Al / Ti (200/3000/200 적층) triple layer is stacked on the SiNx layer. The substrate is patterned on a triple layer using a diamond knife. A specimen was prepared by cutting to 650 mm.

Etching liquid prepared in Examples 1 to 9 and Comparative Examples 1 to 5 was put into a spray-type etching test equipment (manufactured by SEMES, model name: ETCHER (TFT)), and the temperature was set to 40 ° C., followed by heating. After reaching 40 ± 0.5 ° C., an etching process was performed. Total etch time was given at 40% based on EPD. Insert the specimen, start spraying, remove it when etching is complete, clean with deionized water, dry using a hot air drying device, and use an electron scanning microscope (SEM; manufactured by Hitachi, model name: S-4700). The inclination angle, side etch (CD) loss, etch residue and underlying film damage of the etch profile were evaluated and the results are shown in Table 2 and SEM images are shown in FIGS.

[Etch Profile Evaluation Criteria]

◎: excellent

○: good

×: defective

Type of thin film Etch profile Lower membrane damage Residue Remarks Example 1 Ti / Al / Ti ◎ none none - Example 2 ◎ none none - Example 3 ○ none none - Example 4 ○ none none - Example 5 ◎ none none - Example 6 ○ none none - Example 7 ◎ none none - Example 8 ○ none none - Example 9 ○ none none - Comparative Example 1 X none none Upper and lower under cut occurs Comparative Example 2 X none none - Comparative Example 3 X none none Upper Ti Tip Comparative Example 4 X has exist none - Comparative Example 5 X has exist none -

In the present invention, in etching a metal film formed of a titanium or titanium alloy film, and a multilayer film including an aluminum or aluminum alloy film, the etching speed is fast, there is no damage to the lower film and the equipment, expensive equipment configuration is not required, and a large area It is advantageous for the present invention to provide an etchant composition having excellent productivity since it has uniform etching properties.

Claims (3)

A titanium or titanium alloy film containing 1 to 20% by weight of HNO ₃ , 0.1 to 10% by weight of H ₂ SO ₄ , 0.01 to 5% by weight of NH ₄ FHF, and a residual amount of water, based on the total weight of the composition, And an aluminum or aluminum alloy film. The titanium according to claim 1, which contains 5 to 15% by weight of HNO ₃ , 0.1 to 5% by weight of H ₂ SO ₄ , and 0.01 to 3% by weight of NH ₄ FHF, based on the total weight of the composition. Or a titanium alloy film, and an aluminum or aluminum alloy film. The double film according to claim 1 or 2, wherein a multilayer film including a titanium or titanium alloy film and an aluminum or aluminum alloy film is a double film in which a titanium or titanium alloy film is stacked on or under an aluminum or aluminum alloy film, and a titanium or titanium alloy film; A multilayer film etchant composition comprising a titanium or titanium alloy film, and an aluminum or aluminum alloy film, wherein the aluminum or aluminum alloy film is a multilayer metal film of at least triple layers in which alternating layers are laminated.

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