WO2011019209A2 - Etchant composition for forming metal interconnects - Google Patents

Abstract

The present invention provides an etchant composition for a metal film comprising at least one film selected from an indium-based transparent conductive film, an aluminum-based metal film and a titanium-based metal film, used for the interconnect of a pixel electrode, a gate electrode, a source electrode and a drain electrode. The etchant composition is excellent in etching characteristics to an indium-based transparent conductive film, an aluminum-based metal film and a titanium-based metal film, respectively, and particularly to an Al-La-based alloy film. In addition, the etchant composition can effectively etch a tri-layered film comprising an indium-based transparent conductive film, an Al-La-based alloy film and a titanium-based metal film at a time.

Description

Etch solution composition for forming metal wiring

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etchant composition used for the wet etching of metal films in the manufacture of semiconductor devices, and more particularly to indium transparent conduction forming pixel electrodes, gate electrodes, source electrodes, and drain electrodes in the construction of flat panel displays. The present invention relates to an etching liquid composition of a metal film composed of at least one film selected from a film, an aluminum metal film, and a titanium metal film.

In order to realize an image of a flat panel display, a transparent pixel electrode, a gate electrode, a source electrode, and a drain electrode are used in a thin film transistor (TFT) array. In general, a transparent conductive film containing indium as a main component is used as the pixel electrode, and a single film or multiple films are used as the main component as Cr, Cu, Mo, Ti, Al, etc. as the gate electrode, the source electrode, and the drain electrode.

Recently, in order to simplify the production process and increase the production volume, an indium transparent conductive film mainly composed of indium in the upper layer, an aluminum metal film mainly composed of aluminum in the middle layer, and a titanium metal film mainly composed of titanium in the lower layer are used. A new triple film composed is also being developed. Therefore, in order to efficiently etch, it is required to develop an etchant that can wet-etch the triple layer as described above.

The aluminum-based metal film is made of aluminum and La, Mg, Zn, In, Ca, Te, Sr, Cr, Co, Mo, Nb, Ta, W in order to avoid process problems caused by hillock due to heat of aluminum. Alloys made of metals such as, Ni, Nd, Sn, Fe, Si, Ti, Pt, and C have been developed in various ways. In particular, Al-La alloys containing Al-La alloys or other metals with Al-La as main components An aluminum alloy of the form -X was developed. The other metal means Mg, Zn, In, Ca, Te, Sr, Cr, Co, Mo, Nb, Ta, W, Ni, Nd, Sn, Fe, Si, Ti, Pt, C, etc. Is an alloy composed mainly of aluminum, which is 90% or more of aluminum and 10% or less of La, Mg, Zn, In, Ca, Te, Sr, Cr, Co, Mo, Nb, Ta, W, Ni, Nd, Sn, Components such as Fe, Si, Ti, Pt, and C are included.

By the way, in the case of the conventional aluminum metal film can be etched with a conventional phosphate-based aluminum etchant, in the case of the Al-La or Al-La-X type aluminum alloy film when using an etchant of the existing composition, Due to the difference in etching speed between the aluminum-based metal film and the photoresist, and the aluminum-based metal film and the glass portion, curling occurs on the upper portion of the aluminum-based metal film, resulting in a poor profile. This poor profile results in poor step coverage in the subsequent process and increases the likelihood that the top layer is disconnected from the slope or the upper and lower metals are shorted.

Therefore, in order to efficiently etch the triple layer efficiently, an etchant having excellent etching characteristics for each of an indium transparent conductive film, an aluminum metal film, and a titanium metal film is required, and in particular, Al- which can be used as an aluminum metal film. An etching solution capable of efficiently etching La or Al-La-X type aluminum alloy films has to be developed.

The present invention has excellent etching characteristics for each of an indium-based transparent conductive film, an aluminum-based metal film, and a titanium-based metal film. An object of the present invention is to provide an etching liquid composition capable of efficiently collectively etching a triple film made of a -La-based alloy film and a titanium-based metal film.

The present invention comprises 0.1 to 10% by weight of nitric acid, 0.1 to 10% by weight of sulfuric acid, 0.01 to 5% by weight of fluorine-containing compound and the balance of water based on the total weight of the composition. An etching liquid composition of a metal film composed of at least one film selected from the group metal films is provided.

The etching liquid composition of the present invention has excellent etching characteristics for each of the indium-based transparent conductive film, the aluminum-based metal film, and the titanium-based metal film, and particularly, the etching property of the Al-La-based alloy film which can be used as the aluminum-based metal film is Excellent, it is possible to efficiently etch a triple layer composed of an indium-based transparent conductive film, an Al-La-based alloy film and a titanium-based metal film. Therefore, the etchant composition of the present invention provides the effect of greatly improving productivity by simplifying the etching process.

1 is an electron scanning micrograph showing the result of etching the a-ITO / AlLaNi / Ti triple layer with the etchant of Example 7.

FIG. 2 is an electron scanning micrograph showing the result of etching a-ITO / AlLaNi / Ti triple layer with the etchant of Comparative Example 2. FIG.

The present invention is an indium-based transparent conductive film, an aluminum-based metal film, containing 0.1 to 10% by weight of nitric acid, 0.1 to 10% by weight of sulfuric acid, 0.01 to 5% by weight of a fluorine-containing compound, and a residual amount of water based on the total weight of the composition The present invention relates to an etching liquid composition of a metal film composed of one or more films selected from titanium-based metal films.

In the present invention, the indium-based transparent conductive film means a transparent conductive film containing indium as a main component, and specific examples include indium oxide films such as indium zinc oxide film (IZO) and indium tin oxide film (ITO).

The aluminum-based metal film means an aluminum film or an aluminum alloy film containing aluminum as a main component.

The titanium-based metal film means a titanium film or a titanium alloy film containing titanium as a main component. As said titanium alloy film, alloy films, such as Ti and W, Mo, Nd, Ni, Ta which have Ti as a main component, are mentioned, for example.

In the present invention, the metal film composed of at least one film selected from an indium-based transparent conductive film, an aluminum-based metal film, and a titanium-based metal film includes a single film and a multi-layered film (multilayer film).

In particular, the etchant composition of the present invention can be preferably used for batch etching of a triple layer in which an indium-based transparent conductive film is formed on an upper layer, an aluminum-based metal film is formed on an intermediate layer, and a titanium-based metal film is formed on a lower layer.

In addition, the etchant composition of the present invention can be more preferably used for etching a metal film (single film or multiple films) including an Al-La-based alloy film. For example, Al-La type alloy film; Alternatively, the indium-based transparent conductive film may be formed on the upper layer, the Al-La-based alloy film is formed on the intermediate layer, and the titanium-based metal film may be more preferably used for batch etching of the triple layer formed on the lower layer.

In the present invention, the Al-La-based alloy film is Al-La or Al-La-X containing 90% by weight or more of aluminum and 10% by weight or less of La (X is Mg, Zn, In, Ca, Te, Sr, Cr, At least one metal) alloy film selected from Co, Mo, Nb, Ta, W, Ni, Nd, Sn, Fe, Si, Ti, Pt, and C). When an Al-La or Al-La-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 the heat of aluminum can be avoided.

When etching the Al-La-based alloy film with the etchant composition of the present invention, the Al-La-based alloy film and photoresist, Al-La-based alloy film and the upper portion of the substrate, which is a problem when using the etching solution of the existing composition Curling phenomenon on the Al-La alloy layer due to the difference in etching speed; Bad angle of inclination; Poor uniformity; Since the problem of side etch increase due to the difference in etching between the panel and the pad does not occur, the Al-La alloy film can be etched very efficiently.

Nitric acid contained in the etchant composition of the present invention serves to oxidize the surface of the indium-based transparent conductive film, the aluminum-based metal film and the titanium-based metal film, and is 0.1 to 10% by weight, more preferably 2 to 7% by weight based on the total weight of the composition. It is contained in%. When the nitric acid is contained in less than 0.1% by weight, the etching rate of the aluminum-based metal film and the titanium-based metal film is lowered. This phenomenon causes a difference in the etching rates for each position in the substrate, which leads to tailing of the titanium-based metal film. Cause stains. When the nitric acid exceeds 10% by weight, cracks occur in the photoresist, and the aluminum-based metal film and the titanium-based metal film may be short-circuited due to the infiltration of the chemical solution. Due to the loss of the metal film and the titanium-based metal film, the metal wiring may lose its function.

Sulfuric acid contained in the etchant composition of the present invention serves to oxidize the surface of the aluminum-based metal film and the titanium-based metal film, and as an auxiliary oxidant of the indium-based transparent conductive film, 0.1 to 10% by weight, more preferably based on the total weight of the composition. It is included in 2 to 7% by weight. If the content is less than 0.1% by weight, the etching rate of the aluminum-based metal film is lowered, and staining occurs in the substrate due to the occurrence of residues or non-uniform etching. If the content is more than 10% by weight, the aluminum-based film is caused by excessive etching rate. The metal film and the titanium metal film may be lost.

The fluorine-containing compound included in the etchant composition of the present invention serves to etch the surface of the oxidized aluminum-based metal film and titanium-based metal film, 0.01 to 5% by weight, more preferably 0.1 to 2% by weight relative to the total weight of the composition It is contained in%. When the fluorine-containing compound is contained in less than 0.01% by weight, the etching rate of the aluminum-based metal film and the titanium-based metal film is reduced, thereby causing uneven etching in the substrate. When the fluorine-containing compound exceeds 5% by weight, the aluminum-based metal film and the titanium-based metal film may be lost due to excessive etching rate, and damage to the lower layer may occur.

The fluorine-containing compound refers to a compound capable of dissociating fluorine ions or polyatomic fluorine ions in a dissolved state, and specifically, ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride, potassium bifluoride, or the like. These may be used alone or in combination of two or more.

It is preferable to use deionized water as water contained in the etching liquid composition of this invention, and it is preferable to use the deionized water as 18 dl / cm or more for a semiconductor process.

The etchant composition of the present invention may further include at least one of an etch regulator, a surfactant, a metal ion sequestrant, a corrosion inhibitor and a pH regulator in addition to the above-mentioned components.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples. The following examples may be appropriately modified or changed by those skilled in the art within the scope of the present invention.

Examples 1 to 10 and Comparative Examples 1 to 3: Preparation of the etchant composition

The components shown in Table 1 were mixed according to the corresponding composition ratios to prepare 180 kg of an etchant composition.

Table 1 nitric acid Sulfuric acid NH4FHF water Example 1 2 2 0.3 95.7 Example 2 3 2 0.3 94.7 Example 3 3 3 0.5 93.5 Example 4 4 2 0.3 93.7 Example 5 4 3 0.5 92.5 Example 6 5 2 0.3 92.7 Example 7 5 3 0.5 91.5 Example 8 6 4 0.5 89.5 Example 9 7 5 0.5 87.5 Example 10 7 5 0.7 87.3 Comparative Example 1 5 2 0.0 93.0 Comparative Example 2 12 3 0.3 84.7 Comparative Example 3 12 8 3 77

         (Unit: weight%)

Test Example: Evaluation of Etch Characteristics

As the test substrate, (1) Al-La-Ni alloy single layer was deposited on glass, photoresist was patterned in a certain shape, and (2) a-ITO / AlLaNi / Ti triple layer was deposited on SiNx layer. The photoresist was patterned into a shape of a certain shape.

After the etching solution prepared in Examples 1 to 10 and Comparative Examples 1 to 3 in the experimental equipment of the spray etching method (manufactured by SEMES, model name: ETCHER (TFT)) and set the temperature to 30 ℃ and warmed, After reaching 30 ± 0.1 ° C., an etching process was performed. Total etch time was given at 30% based on EPD. Insert the specimen, start spraying, and when the etching is complete, taken out, washed with deionized water, dried using a hot air drying apparatus, and removed the photoresist using a photoresist stripper (PR) stripper. After cleaning and drying, an electron scanning microscope (SEM: manufactured by HITACHI, model name: S-4700) was used to evaluate the inclination angle of the etching profile, the loss of critical dimension (CD), the etching residue and the underlying film damage. The results are shown in Table 2 below.

[Evaluation Criteria of Etch Profile]

◎: Excellent (CD Skew: ≤1㎛, Taper Angle: 40 ° ~ 80 °)

○: Excellent (CD Skew: ≤1.5㎛, Taper Angle: 40 ° ~ 80 °)

△: Good (CD Skew: ≤2㎛, Taper Angle: 40 ° to 80 °)

X: Poor (metal film loss and residue)

TABLE 2 Etch Profile Lower membrane damage Residue Al-La-Ni a-ITO / AlLaNi / Ti Al-La-Ni a-ITO / AlLaNi / Ti Al-La-Ni a-ITO / AlLaNi / Ti Example 1 ○ ○ none none none none Example 2 ◎ ◎ none none none none Example 3 ◎ ◎ none none none none Example 4 ◎ ◎ none none none none Example 5 ◎ ◎ none none none none Example 6 ◎ ◎ none none none none Example 7 ◎ ◎ none none none none Example 8 ◎ ◎ none none none none Example 9 ◎ ◎ none none none none Example 10 ◎ ◎ none none none none Comparative Example 1 × × Titanium Film Not Etched Comparative Example 2 × × none none none none Comparative Example 3 × × has exist has exist none none

As can be seen from Table 2, the etchant composition of Examples 1 to 10 of the present invention is not only applied to (1) Al-La-Ni alloy single layer, but also to (2) a-ITO / AlLaNi / Ti triple layer. Also excellent etching profile was shown, there was no damage to the underlying film and residue (see Fig. 1). However, in the case of Comparative Example 1 etchant containing no fluorine-containing compound, the etching profile defect and the (2) a-ITO / AlLaNi / Ti triple layer were not only applied to (1) Al-La-Ni alloy single layer. Unetch of the Ti film occurred, and the etching solution of Comparative Examples 2 and 3 containing an excess of nitric acid also exhibited poor etch profile and / or damage to the underlying film (see FIG. 2).

Claims (9)

An indium-based transparent conductive film, an aluminum-based metal film, and a titanium-based metal film containing 0.1 to 10% by weight of nitric acid, 0.1 to 10% by weight of sulfuric acid, 0.01 to 5% by weight of fluorine-containing compound, and a balance of water based on the total weight of the composition. Etch liquid composition of a metal film composed of one or more membranes selected from. The method of claim 1, wherein the indium transparent conductive film is an indium zinc oxide film (IZO) or indium tin oxide film (ITO); The aluminum-based metal film is an aluminum film or an aluminum alloy film containing aluminum as a main component; The titanium-based metal film is an etching liquid composition of a metal film composed of at least one film selected from an indium-based transparent conductive film, an aluminum-based metal film and a titanium-based metal film, characterized in that the titanium film or a titanium alloy film containing titanium as a main component. The method of claim 1, wherein the indium-based transparent conductive film, an aluminum-based metal film and a metal film composed of at least one film selected from the titanium-based metal film, the indium-based transparent conductive film is formed on the upper layer, the aluminum-based metal film is formed on the intermediate layer And an indium-based transparent conductive film, an aluminum-based metal film, and a titanium-based metal film, wherein the titanium-based metal film is a triple film formed of a lower layer. The method of claim 1, wherein the fluorine-containing compound is a compound capable of dissociating fluorine ions or polyatomic fluorine ions in the dissolved state, ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride, and potassium bifluoride An etching liquid composition of a metal film composed of at least one film selected from indium-based transparent conductive film, aluminum-based metal film and titanium-based metal film, characterized in that one or two or more selected from the group consisting of. The indium transparent conductive film, the aluminum-based metal film, and the titanium-based material of claim 1, wherein the etchant composition further comprises one or more components of an etch regulator, a surfactant, a metal ion sequestrant, a corrosion inhibitor, and a pH regulator. An etchant composition of a metal film composed of at least one film selected from metal films. The method of claim 1, wherein the metal film composed of at least one film selected from the indium-based transparent conductive film, aluminum-based metal film and titanium-based metal film is characterized in that the single film or a multi-layer including an Al-La-based alloy film An etching liquid composition of a metal film composed of at least one film selected from an indium transparent conductive film, an aluminum metal film, and a titanium metal film. The method of claim 6, wherein the Al-La-based alloy film is Al-La or Al-La-X containing 90% by weight or more of aluminum and 10% by weight or less of La (X is Mg, Zn, In, Ca, Te, Sr At least one metal selected from Cr, Co, Mo, Nb, Ta, W, Ni, Nd, Sn, Fe, Si, Ti, Pt, and C) alloy films. An etching liquid composition of a metal film composed of at least one film selected from a metal film and a titanium metal film. The multilayer film including the Al-La-based alloy film is a triple film in which an indium-based transparent conductive film is formed on an upper layer, an Al-La-based alloy film is formed on an intermediate layer, and a titanium-based metal film is formed on a lower layer. An etching liquid composition of a metal film composed of at least one film selected from an indium transparent conductive film, an aluminum metal film and a titanium metal film. The method of claim 8, wherein the Al-La-based alloy film is Al-La or Al-La-X containing at least 90% by weight aluminum and 10% by weight La (X is Mg, Zn, In, Ca, Te, Sr At least one metal selected from Cr, Co, Mo, Nb, Ta, W, Ni, Nd, Sn, Fe, Si, Ti, Pt, and C) alloy films. An etching liquid composition of a metal film composed of at least one film selected from a metal film and a titanium metal film.

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