KR20210036633A - Etchant composition for metal layer and etching method of metal layer using the same - Google Patents

Abstract

The present invention relates to a metal film etchant compound having excellent etching characteristics and easy control of an etching rate when etching a metal film, and a method for etching a metal film using the same. According to the present invention, the metal film etchant compound contains hydrogen peroxide, pernitrate, a compound represented by the following chemical formula 1-1, and a compound represented by the following chemical formula 2-1.

Description

Metal film etchant composition and etching method of metal film using the same {ETCHANT COMPOSITION FOR METAL LAYER AND ETCHING METHOD OF METAL LAYER USING THE SAME}

The present invention relates to a metal film etchant composition and a method of etching a metal film using the same.

The microcircuit process or semiconductor integrated circuit manufacturing process of a liquid crystal display device is performed on a substrate with an insulating film such as a conductive metal film such as aluminum, aluminum alloy, copper, copper alloy, molybdenum, molybdenum alloy, or silicon oxide film, silicon nitride film, fork acrylic insulating film, etc. After forming the same various lower films, uniformly coating a photoresist on these lower films, and selectively performing exposure and development treatment to form a photoresist pattern, use the patterned photoresist film as a mask to form the conductive metal film or insulating film. The microcircuit pattern is transferred to the lower layer of the photoresist by wet or dry etching, and then the unnecessary photoresist layer is removed with a stripper (a peeling solution).

At this time, the metal film etchant composition used in manufacturing the semiconductor device and the liquid crystal display device should be able to remove the metal film within a suitable time and should not leave the etchant composition on the substrate after washing. In addition, various characteristics required at the time of etching, that is, the taper angle should be appropriate, the etching loss should be small, etc. should be satisfied.

However, conventionally used etchant compositions have problems such as a problem in the process margin because the etching rate is too fast, or the taper angle is not appropriate, making the subsequent process difficult.

Accordingly, there is a need to develop a new etchant composition having excellent etching characteristics, such as easy control of the etch rate, low etch loss, and having an appropriate taper profile.

An object of the present invention is to provide a metal film etchant composition having excellent etching characteristics and easy control of an etch rate when etching a metal film.

In addition, the present invention is to provide a method for etching a metal film using the metal film etchant composition.

In the present specification, there is provided a metal film etchant composition comprising hydrogen peroxide, pernitrate, a compound represented by the following Formula 1-1, and a compound represented by the following Formula 2-1:

[Formula 1-1]

[Formula 2-1]

In Formulas 1-1 and 2-1,

L is each independently a substituted or unsubstituted C 1 to C 5 alkylene,

Each R is independently substituted or unsubstituted alkyl having 1 to 5 carbon atoms.

In the present specification, there is also provided a method of etching a metal film, including etching with the metal film etchant composition using a photoresist pattern formed on a liquid crystal display device including a metal film or a semiconductor substrate as a mask.

Hereinafter, a metal film etchant composition according to a specific embodiment of the present invention and a method of etching a metal film using the same will be described in more detail.

The terms used in the present specification are only used to describe exemplary embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise", "include", or "have" are intended to designate the existence of a feature, number, step, element, or combination of the implemented features, but one or more other features or It is to be understood that the possibility of the presence or addition of numbers, steps, elements, or combinations thereof is not preliminarily excluded.

The present invention will be described in detail below and exemplify specific embodiments, as various modifications can be made and various forms can be obtained. However, this is not intended to limit the present invention to a specific form of disclosure, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

According to an embodiment of the present invention, a metal film etchant composition comprising hydrogen peroxide, pernitrate, a compound represented by Formula 1-1, and a compound represented by Formula 2-1 may be provided.

The present inventors have conducted research on the metal film etchant composition, and the metal film etchant composition including the above-described components facilitates control of the etch rate when etching the metal film, low etch loss (CD loss) and high taper angle ( It has been confirmed through an experiment that it has excellent etching characteristics, such as having a taper angle, and the invention was completed.

The metal film etchant composition of the embodiment includes hydrogen peroxide and pernitrate, and may have an effect of effectively controlling the etching process by properly maintaining an etch rate, and the compound represented by Formula 1-1 and Formula 2 By including the compound represented by -1, it is possible to reduce etching loss and to have an appropriate taper angle.

In particular, the metal film etchant composition of the embodiment includes both the compound represented by Formula 1-1 and the compound represented by Formula 2-1, and has a role of inhibiting molybdenum galvanic corrosion, and corrosion by a chelating effect with copper. Control and increase the stability of the solution. Accordingly, when etching a metal film, especially a copper film, a copper alloy film, a molybdenum film, a molybdenum alloy film, a copper/molybdenum double film, or a multilayer including a copper/molybdenum double film, it plays a role in increasing the process margin by reducing the etching loss It can be used and it has a high taper angle to enable efficient etching.

Meanwhile, the compound represented by Formula 1-1 and the compound represented by Formula 2-1 are in a weight ratio of 1:1 to 1:20, or 1:1 to 1:19, or 1:1 to 1:18. May be included, and as the compound represented by Formula 1-1 and the compound represented by Formula 2-1 have the specific weight ratio described above, the metal film etchant composition is etched while maintaining a constant taper angle. , It maintains the etching uniformity and has excellent etching characteristics.

When the weight ratio between the compound represented by Formula 1-1 and the compound represented by Formula 2-1 is less than 1:1, a problem of molybdenum galvanic corrosion may occur, and when it exceeds 1:20, the taper angle Is lowered and there is a concern that a problem of lowering the etching rate may occur.

When the compound represented by Formula 1-1 and the compound represented by Formula 2-1 are used together, CD loss is small, galvanic corrosion of molybdenum is small, and a high taper of copper is formed due to their mutual complex action. In addition, when included in a specific amount as described above, the efficiency of etching can be maximized.

Meanwhile, the compound represented by Formula 1-1 may be included in an amount of 0.1 to 10% by weight, or 0.2 to 8% by weight, or 0.3 to 5% by weight, based on the total composition. If the content of the compound represented by Formula 1-1 is less than 0.1% by weight of the total composition, a problem of lowering the taper angle may occur, and if it exceeds 10% by weight, a problem of increasing the etch rate may occur.

This effect of the compound represented by Formula 1-1 can be maximized when used in a specific amount together with the compound represented by Formula 2-1.

In addition, the compound represented by Formula 2-1 may be included in an amount of 0.5 to 15% by weight, or 1 to 12% by weight, or 1.5 to 10% by weight, based on the total composition. Similarly, if the content of the compound represented by Formula 2-1 is less than 0.5% by weight of the total composition, molybdenum corrosion may occur, and if it exceeds 15% by weight, the taper angle decreases and the etching rate increases. Can occur.

This effect of the compound represented by Formula 2-1 can be maximized when used in a specific amount together with the compound represented by Formula 1-1 as described above.

On the other hand, in Formulas 1-1 and 2-1,

L is each independently substituted or unsubstituted alkylene having 1 to 5 carbon atoms, or is, and may be a substituted or unsubstituted alkylene having 1 to 3 carbon atoms,

Each R may be independently substituted or unsubstituted alkyl having 1 to 5 carbon atoms, or alkyl having 1 to 3 carbon atoms.

Meanwhile, the compound represented by Formula 1-1 may be a compound represented by Formula 1-2 below:

[Formula 1-2]

.

.

In addition, the compound represented by Formula 2-1 may be a compound represented by the following Formula 2-2:

[Formula 2-2]

.

.

Meanwhile, the metal film etchant composition of the embodiment includes hydrogen peroxide and pernitrate, and the hydrogen peroxide is a component for etching the metal film, and may serve to secure an excellent etching rate of the metal film etchant composition.

The hydrogen peroxide is 1 to 15% by weight based on the total composition; Alternatively 2 to 13% by weight; Or it may be included in 5 to 10% by weight. If the content of hydrogen peroxide is less than 1% by weight of the total composition, the etching time is too slow and the process time is prolonged, and if it exceeds 15% by weight, the solution may become unstable, resulting in an explosion risk. There is an inefficient problem in

Meanwhile, the metal layer etchant composition includes pernitrate, and the pernitrate serves to maintain an etching rate for the metal layer, thereby improving etching efficiency.

The pernitrate may be included in an amount of 0.1 to 10% by weight, or 0.2 to 8% by weight, or 0.3 to 5% by weight, based on the total composition. As the pernitrate is included in the content in the total composition, the effect of controlling the etching rate during etching of the metal layer may be secured.

Examples of the pernitrate are not largely limited, for example, potassium pernitrate (KNO ₄ ), sodium pernitrate (NaNO ₄ ) or ammonium _{pernitrate (NH 4} NO ₄ ) is a mixture of 1 type, 2 types or 3 types. It may be one or more selected from the group consisting of.

Meanwhile, the metal film etchant composition according to the embodiment may further include an organic acid, an azole-based compound, and a residual amount of water. By further including hydrogen peroxide, pernitrate, the compound represented by Formula 1-1, and the compound represented by Formula 2-1, an organic acid, an azole compound, and a residual amount of water, the etching process was performed by maintaining an appropriate etching rate. It can have the effect of controlling effectively.

Specifically, the metal film etchant composition may include an organic acid. The organic acid may serve to improve the efficiency of etching by allowing the metal layer etchant composition to secure sufficient etching ability.

The organic acid may be included in an amount of 0.1 to 20% by weight, or 0.5 to 18% by weight, or 1 to 15% by weight, based on the total composition. When the content of the organic acid is less than 0.1% by weight of the total composition, sufficient etching ability may not be secured, and when it exceeds 20% by weight, overetching may occur.

Examples of the organic acid are not largely limited, but specifically, for example, lactic acid, malonic acid, succinic acid, glycolic acid, oxalic acid, oxalic acid (oxalacetic acid), fumaric acid, malic acid, acetic acid, butyric acid, palmitic acid, tartaric acid, ascorbic acid ), uric acid, sulfonic acid, sulfinic acid, formic acid, citric acid, isoctric acid and α-ketoglutaric acid ) May be one or more selected from the group consisting of, and specifically, may be one or more selected from the group consisting of lactic acid, malonic acid, succinic acid, and glycolic acid.

Meanwhile, the metal film etchant composition may include an azole-based compound. The azole-based compound may serve to reduce an etching loss of the metal layer etchant composition and to have an appropriate taper angle.

The azole-based compound may be included in an amount of 0.1 to 2% by weight, or 0.15 to 2% by weight, or 0.17 to 1.5% by weight, or 0.2 to 1% by weight, based on the total composition. If the content of the azole-based compound is less than 0.1% by weight with respect to the total composition, the taper angle may be lowered and a CD loss problem may occur. In addition, if the content of the azole-based compound is more than 2% by weight based on the total composition, a problem of lowering the etching rate may occur.

Examples of the azole-based compound are not largely limited, but, for example, triazole-based compounds, aminotetrazole-based compounds, imidazole-based compounds, indole-based compounds, purine ( purine) compounds, pyrazol compounds, pyridine compounds, pyrimidine compounds, pyrrole compounds, pyrrolidine compounds and pyrroline compounds It may be one or more selected from the group consisting of compounds.

Specifically, it may be benzotriazole, aminotetrazole, aminotetrazole potassium salt, imidazole, or pyrazole.

Meanwhile, the pH of the metal film etchant composition according to the embodiment may be 2.0 to 5.5, or 2.5 to 5.0, or 3.0 to 4.5, and when the pH is in the above range, the efficiency of etching may be maximized. Accordingly, hydrogen peroxide, pernitrate, the compound represented by Formula 1-1, and the compound represented by Formula 2-1 in the etchant composition may be adjusted to have a pH within the above range with an appropriate amount.

On the other hand, any one selected from the group consisting of a metal film, for example, a copper film, a copper alloy film, a molybdenum film, a molybdenum alloy film, a copper/molybdenum double film, and a multilayer including a copper/molybdenum double film under the conditions of pH 2.0 to 5.5 The etching rate of the composition for the metal layer of may be 10 nm/sec or more.

As described above, the metal film etchant composition of the embodiment is easy to control the etch rate when etching the metal film, and hydrogen peroxide, pernitrate in the etchant composition, the compound represented by Formula 1-1, and the formula 2-1. By adjusting the compound to be an appropriate amount, the etching rate of the composition may be 10 nm/sec or more under the conditions of pH 2.0 to 5.5. When the etching rate is higher than the above rate, the etching process time is shortened, and thus the cost may be reduced during the process.

Meanwhile, according to another embodiment of the present invention, a method for etching a metal film, comprising the step of etching with the metal film etchant composition of the one embodiment by using a photoresist pattern formed on a liquid crystal display device including a metal film or a semiconductor substrate as a mask. Can be provided.

The etching is performed by a conventional method in the art, but may preferably be performed by a dip method or a spray method. In addition, the specific type, component, or physical properties of the metal film to be etched are not limited, for example, a copper film, a copper alloy film, a molybdenum film, a molybdenum alloy film, a copper/molybdenum double film, or a copper/molybdenum double film. It may include an included multilayer, and the like.

Specifically, forming a metal film on the substrate; Uniformly applying a photoresist on the metal film, and selectively performing exposure and development treatment to form a photoresist pattern; Etching the metal film with the metal film etchant composition of the embodiment using the patterned photoresist film as a mask, and etching the metal film.

The contents of the metal film etchant composition include the above-described contents with respect to the embodiment.

The metal film etchant composition of the above embodiment can effectively control the etching process by properly maintaining the etching rate, reduce etch loss, and have an appropriate taper angle, and specifically, for less than 90 sec under a temperature condition of 30 to 35 degrees Celsius. When etching is performed, the CD loss for the metal layer of the composition may be 0.8 μm or less, or 0.79 μm or less.

If the etching loss exceeds 0.8 μm under the above conditions, the wiring may be short-circuited and peeling may occur, resulting in a defective rate.

In addition, when the metal layer is etched by the above etching method, a taper angle of the metal layer after etching may be adjusted to be 55 degrees or more, 56 degrees or more, or 57 degrees or more. When the taper angle is less than 55 degrees, there is a problem in that the aperture ratio decreases, resulting in a decrease in transmittance of the liquid crystal display. In particular, the taper angle is one of very important performance factors in the 8K wiring.

According to the present invention, a metal film etchant composition having excellent etching characteristics and easy control of an etch rate when etching a metal film, and a method of etching a metal film using the same can be provided.

1 is a scanning electron microscope (SEM) photograph showing a result of etching a triple layer of molybdenum alloy/copper/molybdenum (Mo alloy/Cu/Mo) with the etchant composition according to Example 1 of the present invention.
Figure 2 is a molybdenum alloy/copper/molybdenum (Mo alloy/Cu/Mo) triple layer after etching with the etchant composition according to Example 1 of the present invention. This is a photograph observed with a microscope (SEM).

The invention will be described in more detail in the following examples. However, the following examples are merely illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

<Examples 1 to 4: Preparation of metal film etchant composition>

According to the composition of Table 1 below, each component was mixed to prepare metal film etchant compositions of Examples 1 to 4, respectively. The specific composition of the prepared metal film etchant composition is as described in Table 1 below.

Composition of metal film etchant composition division Example 1
(wt%) Example 2
(wt%) Example 3
(wt%) Example 4
(wt%) Compound A 2 1.5 One 0.5 Compound B 2 5 7 9 H ₂ O ₂ 8 8 9 9 Pernitrate One 0.5 One 0.5 Organic acid 7 9 11 15 Azole compounds 0.5 0.5 One One water 81.5 80.5 70 65.5 pH 4.4 4.45 4.5 4.5

* Compound A: N,N-Bis(3-aminopropyl)ethylenendiamine

* Compound B: N,N-Dimethyl-1,3-diaminopropane

* Pernitrate: sodium pernitrate (NaNO ₃ )

* Organic acid: lactic acid, malonic acid, succinic acid and glycolic acid are mixed in a ratio of 1:1:2:2

* Azole compounds: aminotetrazole (Aminotetrazole)

<Comparative Examples 1 to 4: Preparation of metal film etchant composition>

According to the composition of Table 2 below, each component was mixed to prepare a metal film etchant composition of Comparative Examples 1 to 4, respectively. The specific composition of the prepared metal film etchant composition is as described in Table 2 below.

Composition of metal film etchant composition division Comparative Example 1
(wt%) Comparative Example 2
(wt%) Comparative Example 3
(wt%) Comparative Example 4
(wt%) Amine compounds 3 5 7 10 H ₂ O ₂ 8 9 8 9 Pernitrate One 2 One 2 Organic acid 8 10 12 15 Azole compounds One One 0.5 0.5 water 79 73 71.5 63.5 pH 3.6 3.7 3.9 4.1

* Amine compound: Monoethanol Amine

* Pernitrate: sodium pernitrate (NaNO ₃ )

* Organic acid: lactic acid, malonic acid, succinic acid and glycolic acid are mixed in a ratio of 1:1:2:2

* Azole compounds: aminotetrazole (Aminotetrazole)

<Experimental Example: Measurement of physical properties of etchant compositions obtained in Examples and Comparative Examples>

Etching properties of the molybdenum alloy/copper/molybdenum (Mo alloy/Cu/Mo) triple layer were evaluated for the etchant compositions prepared in Examples and Comparative Examples as follows. At this time, the specimen used in the experiment is a glass substrate that has undergone a gate process in the fabrication of a TFT (Thin Film Transistor) circuit of a liquid crystal display, and after forming a Mo layer of 300 Å and a Cu layer of 6500 Å and a Mo alloy layer of 180 Å on the glass. After formation, a positive photoresist was applied, dried, and a pattern was formed by photolithography.

1. Etch rate measurement

The thickness of the etched sample was measured using an electron scanning microscope (SU-8010, manufactured by HITACHI), and the longitudinal etching rate was measured by dividing the thickness of the etched sample by the etching time. The rates of the etchant compositions of Examples 1 to 4 and Comparative Examples 1 to 4 were measured in the same manner as described above, and are shown in Table 3 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Etching speed
(nm/sec) 11.0 11.0 10.5 10.5 8 8 7 7

As shown in Table 3, it was confirmed that the etchant compositions of Examples 1 to 4 have superior etch rates compared to the etchant compositions of Comparative Example.

2. Measurement of CD loss

The specimen was etched by dipping or spraying for 30 seconds to 120 seconds in an etchant composition maintained at 35 degrees according to the etching composition in Tables 1 and 2, and then washed with ultrapure water for 30 seconds and then dried with nitrogen. After drying was completed, the cross section of the specimen in which the photoresist was not removed was observed with a scanning electron microscope (FE-SEM) at a magnification of 50,000 to 200,000, and the distance between the end of the photoresist and the end of the copper film was measured and expressed as an etch loss value. The etching loss of the etchant compositions of Examples 1 to 4 and Comparative Examples 1 to 4 was measured in the same manner as described above, and is shown in Table 4 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 CD loss(㎛) 0.77 0.78 0.79 0.79 0.90 1.0 1.1 1.2

As shown in Table 4, it was confirmed that the etching loss of the etchant compositions of Examples 1 to 4 was 0.8 μm or less, which significantly reduced the etch loss compared to the comparative example. From these results, when using the etchant composition of the example, it is possible to effectively suppress the occurrence of residues by reducing the etch loss.

3. Taper angle measurement

The specimen was etched by dipping or spraying for 30 seconds to 120 seconds in an etchant composition maintained at 35 degrees according to the etching composition in Tables 1 and 2, and then washed with ultrapure water for 30 seconds and then dried with nitrogen. After drying was completed, the cross section of the specimen in which the photoresist was removed was observed with a scanning electron microscope (FE-SEM) with a magnification of 50,000 to 200,000, and the inclination angle of the etched side was measured to indicate the inclination angle. The taper angles of the etchant compositions of Examples 1 to 4 and Comparative Examples 1 to 4 were measured in the same manner as described above, and are shown in Table 5 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 taper angle
(°) 59.7 59.3 59.0 58.4 51.1 49.2 46.2 43.2

As shown in Table 5, it was confirmed that the etchant compositions of Examples 1 to 4 had a taper angle of 55 degrees or more, which was higher than that of the comparative example.

4. Molybdenum (Mo) under-cut measurement

The specimen was etched by dipping or spraying for 30 seconds to 120 seconds in an etchant composition maintained at 35 degrees according to the etching composition in Tables 1 and 2, and then washed with ultrapure water for 30 seconds and then dried with nitrogen. After drying was completed, the cross section of the specimen in which the photoresist was removed was observed with a scanning electron microscope (FE-SEM) with a magnification of 50,000 to 200,000, and the corrosion state formed on the edge of molybdenum (Mo) by etching was observed. The Mo under-cuts of the etchant compositions of Examples 1 to 4 and Comparative Examples 1 to 4 were observed in the same manner as described above, and are shown in Table 6 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Mo under-cut
(㎛) 0 0 0 0 0.1 0.1 0 0

As shown in Table 6, it was confirmed that the etchant compositions of Examples 1 to 4 did not exhibit Mo under-cut.

Claims (14)

A metal film etchant composition comprising hydrogen peroxide, pernitrate, a compound represented by the following formula 1-1, and a compound represented by the following formula 2-1:
[Formula 1-1]

[Formula 2-1]

In Formulas 1-1 and 2-1,
L is each independently a substituted or unsubstituted C 1 to C 5 alkylene,
Each R is independently substituted or unsubstituted alkyl having 1 to 5 carbon atoms.
The method of claim 1,
The weight ratio between the compound represented by Formula 1-1 and the compound represented by Formula 2-1 is 1:1 to 1:20, a metal film etchant composition.
The method of claim 1,
A metal film etchant composition further comprising an organic acid, an azole compound, and a balance of water.
The method of claim 3,
0.1 to 10% by weight of the compound represented by Formula 1-1;
0.5 to 15% by weight of the compound represented by Formula 2-1;
1 to 15% by weight of hydrogen peroxide;
0.1 to 10% by weight pernitrate;
0.1 to 20% by weight of organic acid;
0.1 to 2% by weight of an azole-based compound; And
A metal film etchant composition containing the remaining amount of water.
The method of claim 1,
Formula 1-1 is represented by the following Formula 1-2, a metal film etchant composition:
[Formula 1-2]

.
The method of claim 1,
Formula 2-1 is represented by the following Formula 2-2, a metal film etchant composition:
[Formula 2-2]

.
The method of claim 3,
The organic acid comprises at least one selected from the group consisting of lactic acid, malonic acid, succinic acid, and glycolic acid.
The method of claim 3,
The azole-based compounds are triazole-based compounds, aminotetrazole-based compounds, imidazole-based compounds, indole-based compounds, purine-based compounds, and pyrazole-based compounds. A metal film etchant selected from the group consisting of compounds, pyridine compounds, pyrimidine compounds, pyrrole compounds, pyrrolidine compounds and pyrroline compounds Composition.
The method of claim 1,
The pH of the composition is 2.0 to 5.5, the metal film etchant composition.
The method of claim 1,
Under the conditions of pH 2.0 to 5.5 of the composition for any one metal film selected from the group consisting of a copper film, a copper alloy film, a molybdenum film, a molybdenum alloy film, a copper/molybdenum double film, and a multilayer including a copper/molybdenum double film The etching rate is 10 nm / sec or more, the metal film etchant composition.
A method of etching a metal film, comprising the step of etching with the etchant composition of claim 1 using a photoresist pattern formed on a liquid crystal display device including a metal film or a semiconductor substrate as a mask.
The method of claim 11,
The metal film is a copper film, a copper alloy film, a molybdenum film, a molybdenum alloy film, a copper/molybdenum double film, or a multilayer including a copper/molybdenum double film.
The method of claim 11,
When etching is performed for less than 90 sec under a temperature condition of 30 to 35 degrees, the etching loss for the metal layer of the composition is 0.8 μm or less.
The method of claim 11,
A method of etching a metal film, wherein a taper angle with respect to the metal film after etching is 55 degrees or more.

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