KR20140107867A

KR20140107867A - Etchant composition for copper and titanium layer and method for etching the copper and titanium layer using the same

Info

Publication number: KR20140107867A
Application number: KR1020130021988A
Authority: KR
Inventors: 김수원
Original assignee: (주)에이엠에스아이
Priority date: 2013-02-28
Filing date: 2013-02-28
Publication date: 2014-09-05

Abstract

An etchant composition of a copper film and a titanium film is disclosed. The etching solution composition of the copper film and the titanium film according to the present invention can contain copper sulfate and titanium film at a concentration of less than that of sodium persulfate, hydrofluoric acid, phosphoric acid and benzotriazole, and can simultaneously etch the copper film and the titanium film, Is not generated.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etchant composition for a copper film and a titanium film,

The present invention relates to an etchant composition, and more particularly, to an etchant composition capable of etching a copper film and a titanium film in a metal electrode wiring of a display device, and an etching method using the same.

In order to form a metal wiring on a substrate in a display device such as a liquid crystal display device, a metal film is generally formed by sputtering or the like, and a metal wiring is formed by leaving a metal film in a selective region after coating and exposing the photoresist to light and etching.

The resistance of the metal film used is a major factor causing the RC signal delay, and a technique using a low resistance metal wiring is being developed.

In recent years, copper (Cu), which has a low resistance value and has no environmental problem, has attracted attention as a low-resistance wiring material. However, copper has a poor adhesive force with a glass substrate or a silicon insulating film. In order to solve such problems, a copper alloy film (Cu Alloy), a titanium film (Ti), a titanium alloy film (Ti alloy), a molybdenum film (Mo), a molybdenum alloy film Alloy) is used as a lower film of copper (Cu).

In order to etch the multi-layered film, a high-concentration aqueous etching solution is used. When the concentration of the metal ions exceeds a certain concentration, the high-concentration aqueous etching solution accelerates the decomposition of the water and rapidly decomposes into water and oxygen. I have a problem with stability.

In order to solve this problem, Japanese Patent Laid-Open No. 10-2013-0008331 discloses an etching solution composition of a copper film / titanium film using ammonium persulfate.

However, since the etchant composition of the copper film / titanium film includes ammonium persulfate, ammonium fluoride, and 5-aminotetrazole, the problem that potassium cyanide, which is harmful to the human body, is generated as a byproduct when the copper film / titanium film is etched Of course, the copper taper angle required in the industry can not be provided, and the etching performance deteriorates as the storage period becomes longer, and further, the etching performance deteriorates due to the increase of the copper content, which is difficult to recycle.

SUMMARY OF THE INVENTION The present invention provides an etching solution composition for a copper film and a titanium film having excellent etching performance.

It is another object of the present invention to provide a method of etching using an etching solution composition of a copper film and a titanium film having excellent etching performance.

Disclosure of the Invention In order to solve the above technical problems, the present invention provides an etchant composition of a copper film and a titanium film including sodium persulfate, hydrofluoric acid, phosphoric acid, benzotriazole, and a residual amount of water.

In detail, the present invention is characterized in that the required etching performance (copper film and titanium film should be entirely etchable, the taper angle of the copper film should be 40 ° ± 10 °, the etching loss (CD) of the copper film should be 1.0 μm ± 0.2 μm And the etching performance is maintained even when the copper content in the etchant composition is increased, and the etching performance of the copper film and the titanium film is maintained even when the copper content in the etchant composition is increased.

More particularly, the present invention provides an etchant composition of a copper film and a titanium film, in which after-etching products, especially potassium cyanide, are not produced.

Preferably, the remaining water is deionized water (DI water).

In one embodiment, the copper film and the titanium film are formed of a copper film as an upper film and the titanium film is formed as a lower film, but it is also possible to vertically change the copper film and the titanium film in some embodiments.

It is also possible to use a copper alloy film and a titanium alloy film such as a molybdenum-titanium alloy film or the like, and it is also possible to use a multilayered metal wiring consisting of a first layer containing copper and a second layer containing titanium or molybdenum .

2. The etching solution composition of the copper film and the titanium film according to the present invention comprises 1 to 40% by weight of the sodium persulfate; 0.1 to 20% by weight of the hydrofluoric acid; The phosphoric acid is 1 to 30% by weight; The benzotriazole is 0.001 to 10% by weight, and potassium cyanide is not produced when the copper film and the titanium film are etched.

In detail, sodium persulfate (Na ₂ S ₂ O ₈ ) is the main component for etching the copper film. 1 to 40% by weight of sodium persulfate may be contained in 1 kg of the etching solution composition of the copper film and the titanium film. In this content range, the copper film is etched at a proper amount and an excellent etching profile can be obtained. If the content of sodium persulfate is less than 1% by weight, the copper film may not be etched or the etching rate may be slow. If the content is more than 40% by weight, the etching rate may be increased and it may be difficult to control the process.

The hydrofluoric acid (HF) is a compound which can dissociate into fluorine ions or polyatomic fluorine ions in the etching solution composition of the copper film and the titanium film, and is a main component for etching the titanium film and removes residues that may be formed during etching.

0.1 to 20% by weight of hydrofluoric acid may be contained in 1 kg of the etching solution composition of the copper film and the titanium film. In this content range, the titanium film is etched at a proper amount and an excellent etching profile can be obtained. If the content of hydrofluoric acid is less than 0.1% by weight, the etching rate of the titanium film may be lowered to cause residues. If the content of hydrofluoric acid exceeds 20% by weight, insulating films such as glass and silicon films may be damaged.

Phosphoric acid acts to control the etch rate of the copper and titanium films. 1 to 30% by weight of phosphoric acid may be contained in 1 kg of the etching solution composition of the copper film and the titanium film. In this content range, the copper film and the titanium film are etched in a proper amount and an excellent etching profile can be obtained. If the content of phosphoric acid is less than 1% by weight, the etching rate may be lowered and the etching profile may be poor and residues may be generated. If the content exceeds 30% by weight, an excessive angle may occur and cracks may occur in the photoresist And the etchant composition penetrates through the crack, so that the wiring can be short-circuited.

Benzotriazole serves to control the etch rate of the copper film during etching. The benzotriazole may be contained in an amount of 0.001 to 10% by weight in 1 kg of the etching solution composition of the copper film and the titanium film. In this content range, proper copper etching rate and taper angle can be formed and side etching amount can be controlled. When the content of benzotriazole is less than 0.001% by weight, it is difficult to control the etching rate of copper sufficiently, so that an excessive angle may occur. When the content exceeds 10% by weight, the etching rate of copper lowers, .

3. In one aspect, the etchant composition of the copper film and titanium film of the present invention further comprises pyridine (C ₆ H ₅ N), and the pyridine is 0.1 to 10 wt%. According to the addition of pyridine, the etching performance is maintained even during a long storage period, and the etching performance is maintained even when the copper content in the etching composition is increased.

4. The etchant composition of the copper film and the titanium film according to the present invention further comprises ethylenediamine (H ₂ NCH ₂ CH ₂ NH ₂ ) and the ethylenediamine is 0.1 to 10 wt%. The etchant composition comprising ethylenediamine further improves the etching performance of copper. In addition, it enables mild etching of copper, so that the etching interface is clean.

5. The copper film and the titanium film according to the present invention are characterized in that the copper film and the titanium film are etched with the etchant composition of the copper film and the titanium film of the above 1 to 4.

Specifically, there is provided a method of manufacturing a semiconductor device, comprising: forming a multi-metal film composed of a copper film and a titanium film as wiring material for source and drain electrodes on a substrate; Forming a photoresist in a selective region on the multi-metal film; And etching the copper film and the titanium film with the etchant composition of the copper film and the titanium film of the first to fourth copper films using the photoresist as a mask to form a metal wiring pattern.

As described above, the present invention has the effect that the copper film and the titanium film can be collectively etched at the same time, and potassium cyanide is not produced as a byproduct of the etching process.

In addition, the present invention has an excellent storage stability (storage property).

Further, since the etching performance is maintained even after the etching, the present invention can be reused and has an excellent effect of evaluating the number of treatments.

1A is a photograph of a plane of a copper film and a titanium film etched using the composition of Example 1, observed using an SEM.
FIG. 1B is a photograph of a section of a side surface of a copper film and a titanium film etched using the composition of Example 1, using a SEM to observe the taper angle. FIG.
FIG. 1C is a photograph of a side section of a copper film and a titanium film etched using the composition of Example 1, observed using an SEM, and measuring the etching loss. FIG.
2A is a photograph of a plane of a copper film and a titanium film etched using the composition of Comparative Example 1, observed using an SEM.
FIG. 2B is a photograph of a cross section of a side surface of a copper film and a titanium film etched using the composition of Comparative Example 1, using an SEM. FIG.
2C is an enlarged photograph of the section of FIG. 2B.
3A is a photograph of a plane of a copper film and a titanium film etched using the composition of Comparative Example 2, observed using an SEM.
FIG. 3B is a photograph of a cross section of a side surface of a copper film and a titanium film etched using the composition of Comparative Example 2 using an SEM. FIG.
3C is an enlarged photograph of the section of FIG. 3B.
4A is a photograph of a plane of a copper film and a titanium film etched using the composition of Comparative Example 3, observed using an SEM.
4B is a photograph of a cross section of a side surface of a copper film and a titanium film etched using the composition of Comparative Example 3 using an SEM.
4C is an enlarged photograph of the section of FIG. 4B.
5 is a photograph of a cross section of a side surface of a copper film and a titanium film etched using the composition of Comparative Example 4 using an SEM.

The present invention relates to an etching solution composition of a copper film and a titanium film. Specifically, the present invention provides an etching solution for a copper film and a titanium film, which provides a required etching angle, maintains etching performance even in a long life cycle, and does not generate residues after treatment, particularly potassium cyanide &Lt; / RTI >

In the present invention, 'copper film and titanium film' means a multi-metal film in which a copper film and a titanium film are laminated. Specifically, it includes a double metal film in which a copper film and a titanium film are stacked in this order, a titanium film, and a copper film. In addition, a multi-metal film in which a copper film and a titanium film are alternately stacked in three or more layers such as a copper film, a ternary metal film of a titanium film and a copper film, a ternary metal film of a titanium film, a copper film and a titanium film, a copper film, A copper film, a titanium film, and a multi-metal film of a copper film. At this time, the thickness of the copper film and the titanium film is not particularly limited.

In the present invention, the 'copper film' may be a copper single film composed of only copper and may be formed of aluminum (Al), magnesium (Mg), manganese (Mn), beryllium (Be), hafnium (Hf) Nb), tungsten (W), and vanadium (V).

In the present invention, the 'titanium film' may be a single titanium film composed of titanium alone.

1. Preparation of etching compositions

First, an etching solution composition of a copper film and a titanium film according to the present invention was prepared as follows.

[Example 1]

10% by weight of sodium persulfate, 1% by weight of hydrofluoric acid, 5% by weight of phosphoric acid, 1% by weight of benzotriazole and a residual amount of water were mixed to prepare 1 kg of an etching solution composition of a copper film and a titanium film.

[Example 2]

Example 2 of another embodiment of the present invention is characterized by mixing 10% by weight of sodium persulfate, 1% by weight of hydrofluoric acid, 5% by weight of phosphoric acid, 1% by weight of benzotriazole, 0.5% by weight of pyridine (C ₆ H ₅ N) So that the etching solution composition of the copper film and the titanium film was 1 kg.

[Example 3]

Example 3, which is another embodiment of the present invention, comprises 10 wt% of sodium persulfate, 1 wt% of hydrofluoric acid, 5 wt% of phosphoric acid, 1 wt% of benzotriazole, 2 wt% of ethylenediamine (H ₂ NCH ₂ CH ₂ NH ₂ ) The remaining amount of water was mixed to prepare an etching solution composition of copper and titanium films of 1 kg.

Comparative compositions (Comparative Examples 1 to 4) for comparison with the etching solution compositions of the copper film and the titanium film according to the present invention (Examples 1 to 3) were prepared, and the manufacturing method was as follows.

[Comparative Example 1]

10% by weight of sodium persulfate, 1% by weight of benzotriazole and a residual amount of water were mixed to prepare an etching solution composition of copper and titanium films of 1 kg.

[Comparative Example 2]

10% by weight of sodium persulfate, 1% by weight of benzotriazole, 5% by weight of nitric acid and a residual amount of water were mixed to prepare 1 kg of the etching solution composition of the copper film and the titanium film.

[Comparative Example 3]

10% by weight of sodium persulfate, 1% by weight of benzotriazole, 5% by weight of sulfuric acid and a residual amount of water were mixed to prepare an etching solution composition of copper and titanium films of 1 kg.

[Comparative Example 4]

10 wt% of ammonium persulfate, 1 wt% of ammonium nitrate, 5 wt% of nitric acid, 1 wt% of 5-aminotetrazole and the remaining amount of water were mixed to prepare 1 kg of the etching solution composition of the copper film and titanium film.

Table 1 shows the components of Example 1 and Comparative Examples 1 to 3.

Sodium persulfate Benzotriazole Foshan Phosphoric acid nitric acid Sulfuric acid Comparative Example 1 o o - - - - Comparative Example 2 o o - - o - Comparative Example 3 o o - - - o Example 1 o o o o - -

2. Etch performance test

Experimental samples were prepared in order to grasp the etching performance of the etchant composition (Example 1) of the copper film and the titanium film proposed in the present invention. The test samples were a titanium film and a copper film continuously deposited on a glass substrate. The thicknesses of the titanium film and the copper film were 20 nanometers (nm) and 300 nanometers (nm), respectively. (Patterning).

The etchant composition (Example 1 and Comparative Examples 1 to 3) prepared in a spray-type etching system (ETCHER (TFT)) was placed and heated to 25 ° C. Thereafter, after the temperature reached 25 캜, an etching process was performed. The total etch time was 60 seconds.

Experimental samples were put into experimental equipments and each etching composition was sprayed to etch the test samples. The test samples were taken out of the test equipment, washed with deionized water, and then dried using a hot air dryer.

After cleaning and drying, the cross-section of the side surface of the test sample was observed using a scanning electron microscope (SEM), and the taper angle and etch loss of each of the test samples were measured.

The etching loss was measured by observing the profile of the copper film and the titanium film etched by the above etching method using a scanning electron microscope (SEM) and measuring the distance between the end of the photoresist and the end of the copper film.

On the other hand, the taper angle was measured by observing the profile of the copper film and the titanium film etched by the above-described etching method using a scanning electron microscope (SEM), measuring the taper angle of the etched side surface, .

The etching ability of the etching solution composition of the copper film and the titanium film is required to be such that the taper angle of the copper film is 40 占 10 占 and the etching loss (CD) of the copper film is 1.0 占 퐉 占 0.2 占 퐉.

3. Evaluation of etching performance

In order to confirm the etching performance of the compositions of Example 1 and Comparative Examples 1 to 3, etching tests of the copper film and the titanium film were carried out according to the etching performance test method described above using the respective compositions.

FIG. 1A is a photograph of a plane of a copper film and a titanium film etched using the composition of Example 1 using an SEM, FIG. 1B is a cross-sectional view of a copper film and a titanium film etched using the composition of Example 1 Sectional view of the copper film and the titanium film etched using the composition of Example 1 was observed using an SEM and the etching loss was measured It is a photograph.

Referring to Figs. 1A to 1C, the composition of Example 1 completely etched the copper film and the titanium film. Etching performance The taper angle of the copper film was 41.6 占 and the critical dimension (CD) of the copper film was 1.1014 占 퐉. It was confirmed that the composition of Example 1 was excellent in etching the copper film and the titanium film.

2A is a photograph of a plane of a copper film and a titanium film etched using the composition of Comparative Example 1 using SEM, FIG. 2B is a cross-sectional view of a copper film and a titanium film etched using the composition of Comparative Example 1 2C is an enlarged photograph of the section of Fig. 2B. Fig.

Referring to FIGS. 2A to 2C, the composition of Comparative Example 1 including sodium persulfate, benzotriazole, and a residual amount of water etched only the copper film, and the titanium film was not etched. Moreover, the taper angle of the copper film was formed too steeply. That is, when the composition of Comparative Example 1 was used, there was a problem that the taper angle of the copper film was nearly vertical.

FIG. 3A is a photograph of a plane of a copper film and a titanium film etched using the composition of Comparative Example 2 by SEM, FIG. 3B is a cross-sectional view of a copper film and a titanium film etched using the composition of Comparative Example 2 3C is an enlarged photograph of the section of Fig. 3B. Fig.

3A to 3C, the composition of Comparative Example 2 containing sodium persulfate, benzotriazole, nitric acid, and a residual amount of water etched only the copper film. The surface of the copper film was rough etched. Further, the taper angle of the copper film was measured to be 26.8 DEG. That is, when the composition of Comparative Example 2 is used, there is a problem that the taper angle of the copper film is formed too much.

FIG. 4A is a photograph of the planes of the copper film and titanium film etched using the composition of Comparative Example 3 by SEM, FIG. 4B is a cross-sectional view of the copper film and titanium film etched using the composition of Comparative Example 3 Is observed using SEM, and Fig. 4C is an enlarged photograph of the section of Fig. 4B.

4A to 4C, the composition of Comparative Example 3 containing sodium persulfate, benzotriazole, sulfuric acid, and a residual amount of water only etched the copper film, but the surface of the copper film was very roughly etched. Further, the taper angle of the copper film was measured to be 22.2 DEG. That is, when the composition of Comparative Example 3 is used, there is a problem that the taper angle of the copper film is too much formed.

The compositions of Comparative Example without hydrofluoric acid did not etch the titanium film and the composition of Comparative Example 1 which did not contain inorganic acid did not provide the copper taper angle. Compositions comprising phosphoric acid (Example 1) in mineral acids provided a taper angle that matched the required specifications, and compositions containing nitric acid and sulfuric acid provided a too blunt taper angle. Furthermore, compositions containing nitric acid and sulfuric acid have a very rough etched cross section of the copper film compared to compositions comprising phosphoric acid.

On the other hand, when the copper film and the titanium film were etched using the composition of Example 3 in which ethylenediamine was added to the composition of Example 1, the etching performance of copper was further improved. The copper film has excellent etching boundary and provides clean etching.

4. Evaluation of storage stability (storage characteristics) and number of treatments (etching repeatability)

Three samples completely dissolved by adding copper powder of 2000 ppm, 4000 ppm and 4000 ppm respectively to the composition of Example 2 were prepared and one composition sample of Example 2 in which the copper powder was not separately dissolved was prepared.

In addition, three samples completely dissolved by adding copper powder of 2000 ppm, 4000 ppm and 4000 ppm respectively to the composition of Comparative Example 4 were prepared, and one sample of the composition of Comparative Example 4 in which the copper powder was not separately dissolved was prepared .

Etching tests of the copper film and the titanium film were conducted daily for 5 days using each sample little by little. The etching test method was performed in the same manner as described in the etching performance test.

Each sample was stored at 20 ° C for 5 days. An etching test was carried out by taking out the amount required for the etching test in each of the stored samples.

Table 2 shows the results of taper angle and etching loss measured by SEM after 5 days of etching test.

Elapsed days - Copper content Example 2 Comparative Example 4 1 day -0 ppm 0.8412 [mu] m / 44.6 [ 0.8510 [mu] m / 39.8 [ 1 day -2000 ppm 0.8440 占 퐉 / 46.2 占 0.8691 mu m / 39.5 DEG 1 day -4000 ppm 0.8467 mu m / 46.3 DEG 0.8581 占 퐉 / 39.4 占 -6000 ppm per day 0.8489 mu m / 47.1 DEG 0.8492 mu m / 39.0 DEG 2 days -0 ppm 0.8457 [mu] m / 44.1 [ 0.8477 占 퐉 / 38.6 占 2 days - 2000 ppm 0.8500 μm / 44.5 ° 0.8320 mu m / 38.5 DEG 2 days -4000 ppm 0.8524 占 퐉 / 45.0 占 0.8336 mu m / 37.9 DEG 2 days -6000 ppm 0.8542 占 퐉 / 47.1 占 0.8310 mu m / 37.2 DEG 3 days -0 ppm 0.8487 占 퐉 / 45.9 占 0.8311 mu m / 37.2 DEG 3 days - 2000 ppm 0.8521 占 퐉 / 43.6 占 0.8291 mu m / 36.8 DEG 3 days -4000 ppm 0.8550 占 퐉 / 47.3 占 0.8101 mu m / 36.0 DEG 3 days -6000 ppm 0.8562 占 퐉 / 46.3 占 0.7980 mu m / 35.4 DEG 4 days -0 ppm 0.8521 占 퐉 / 46.2 占 0.8101 mu m / 35.0 DEG 4 days - 2000 ppm 0.8574 占 퐉 / 46.8 占 0.7812 占 퐉 / 34.8 占 4 days -4000 ppm 0.8588 占 퐉 / 46.3 占 0.7728 mu m / 34.2 DEG 4 days -6000 ppm 0.8598 占 퐉 / 45.0 占 0.7554 [mu] m / 33.3 [

Referring to Table 2, the composition of Example 2 satisfied the criterion of a taper angle of 40 ° ± 10 ° and an etching loss (CD) of 1.0 μm ± 0.2 μm.

As a result of the etching test, it is confirmed that the composition of Example 2 to which the copper powder was added as well as the composition of Example 2 to which the copper powder was not added retained the etching performance even after the lapse of time. Further, it was confirmed that the storage stability (storage property) of the composition of Example 2 was excellent.

However, according to the results of the etching test of the composition of Comparative Example 4 in which no copper powder was added, it was confirmed that the etching ability decreased with time and the taper angle became dull. Further, it was confirmed that the composition of Comparative Example 4 to which the copper powder was added deteriorated the etching ability with time.

On the other hand, it can be confirmed that the etching performance of the composition of Example 2 is maintained as the concentration of copper powder is increased (i.e., the number of times of etching the copper film and the titanium film is increased). As a result, it was confirmed that the number of treatments (etching reproducibility) of the composition of Example 2 was excellent.

However, according to the results of the etching test, in Comparative Example 4, it is confirmed that as the concentration of the copper powder increases, that is, as the number of etching times for etching the copper film and the titanium film increases, the etching loss becomes small and the taper angle becomes dull . As a result, it was confirmed that the number of treatments of the composition of Comparative Example 4 was poor.

5. Whether or not potassium cyanide (KCN) is generated

FIG. 5 is a photograph of a cross section of a copper film and a titanium film etched using the composition of Comparative Example 4, using SEM. FIG.

Referring to FIG. 5, when the copper film and the titanium film were etched using the composition of Comparative Example 4, it was confirmed that the by-product after etching was present in the region indicated by red in FIG. 5, and by-products were analyzed by EDX One result was identified as cyanide potassium.

Therefore, when the copper film and the titanium film are etched using the comparative example 4, potassium cyanide is produced. It is assumed that potassium cyanide is produced due to nitrogen (N) of ammonium persulfate and nitric acid contained in the composition of Comparative Example 4. [

However, when the copper film and the titanium film were etched using the composition of Example 1, potassium cyanide was not formed (see Fig. 1). Therefore, when the copper film and the titanium film are etched using the composition of the copper film and the titanium film etching solution according to the present invention, potassium cyanide harmful to the human body is not produced as a by-product.

Claims

Wherein the etching solution composition comprises a copper film and a titanium film, the film comprising sodium persulfate, hydrofluoric acid, phosphoric acid, benzotriazole, and a residual amount of water.

The method according to claim 1,
The sodium persulfate is 1 to 40% by weight;
0.1 to 20% by weight of the hydrofluoric acid;
The phosphoric acid is 1 to 30% by weight;
Wherein the benzotriazole is 0.001 to 10% by weight, and the copper film and the titanium film do not generate potassium cyanide when the copper film and the titanium film are etched.

The method according to claim 1,
Further comprising pyridine (C ₆ H ₅ N)
Wherein the pyridine is present in an amount of from 0.1 to 10% by weight, and the etching performance is maintained even after a long storage period, and the etching performance is maintained even when the copper content in the etching composition is increased.

The method according to claim 1,
Further comprising ethylene diamine (H ₂ NCH ₂ CH ₂ NH ₂ )
Wherein the ethylenediamine is 0.1 to 10% by weight, the copper film and the titanium film.

A method of etching a copper film and a titanium film, wherein the copper film and the titanium film are etched with the etching solution composition of a copper film and a titanium film according to any one of claims 1 to 4.