KR20130046065A - Etchant composition, and method for etching a multi-layered metal film - Google Patents

Abstract

PURPOSE: An etchant composition and an etching method for multiple metal films are provided to effectively control the etching speed of copper by using a phenomenon where fluorine ion lowers the etching speed of the copper. CONSTITUTION: An etchant composition is composed of, in wt%: phosphoric acid of 35-70, nitric acid of 0.5-8, acetic acid of 2-20, a fluorine-containing compound of 0.5-10, and the remaining water. The fluorine-containing compound comprises at least one among HF, NaF, NaF_2, NH_4F, NH_4HF_2, H_2SiF_6, Na_2SiF_6, and KHF_2. The etchant composition can include at least two different kinds of fluorine-containing compounds.

Description

TECHNICAL FIELD [0001] The present invention relates to an etchant composition, and a multi-metal film etching method.

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

It is preferable to use Cu as the metal electrode having a low resistance value. Instead of forming the Cu electrode as a single layer on the substrate, a Cu film is formed as a diffusion barrier under the Cu electrode to form an electrode in the form of a Cu / Ti double layer. It is common to use.

By etching the Cu / Ti double layer, a desired pattern may be formed, and a hydrogen peroxide-based etching solution may be used as an etching solution for performing the etching. For example, Korean Patent No. 10-0415617 "Etchant and a method for manufacturing a metal wiring using the same and a method for manufacturing a thin film transistor" provides a method of etching a Cu / Ti double layer using an etching solution of hydrogen peroxide. However, when the hydrogen peroxide-based etchant is used as an etchant for performing the etching, the pure amount of the etchant is excessively required, thereby increasing the amount of the waste solution, and when the hydrogen peroxide-based etchant contains metal. Since the hydrogen peroxide decomposition reaction proceeds by the metal, it is difficult to maintain the etching solution stably and there is a problem that there is a risk of explosion.

On the other hand, a galvanic reaction is a phenomenon that occurs when different kinds of metals are brought into contact with each other in a solution or an atmosphere. This means that the etching speed significantly changes due to a difference in electrochemical electromotive force between the dissimilar metals. The rate of oxidation / reduction reaction between the dissimilar metals is determined by the relative potential difference in the solution of the dissimilar metals. In general, a metal having a high electrochemical potential among the dissimilar metals in a solution acts as a cathode, so that a reduction reaction becomes dominant and an etching rate becomes slow. A metal having a low potential acts as an anode, And the etching speed becomes faster.

Due to the galvanic phenomenon, when etching a film containing a dissimilar metal such as the Cu / Ti double layer, a problem may occur that part of the film is excessively etched. In order to compensate for this problem, different types of etching solutions may be treated for each of the different types of metals. In this case, however, the manufacturing cost and time increase as the entire etching process becomes complicated, resulting in a decrease in productivity and economic efficiency of the product.

Accordingly, while solving the problems caused by the hydrogen peroxide-based etching solution, it is required to develop a new etching solution that can expect excellent etching characteristics with only one wet etching process for the Cu / Ti bilayer.

The present inventors solve the problem caused by the conventional hydrogen peroxide-based etching solution when performing etching using an etching solution composition containing phosphoric acid, nitric acid, acetic acid, fluorine-containing compound, and water, while the conventional phosphoric acid series Problems such as overetching of copper, abrupt inclination angle, and step width formation with the lower layer, which were caused by too fast copper etching speed, were solved in the etching solution. In addition, the present inventors have found that excellent etching characteristics can be expected with only one wet etching process for Cu / Ti bilayers, and thus, the present application was completed.

Thus, the present application, as an etchant composition, with respect to the total weight of the etchant composition, 35% to 70% by weight phosphoric acid; 0.5 wt% to 8 wt% nitric acid; Acetic acid 2% to 20%; 0.5 wt% to 10 wt% of a fluorine-containing compound; And to provide an etchant composition comprising a residual amount of water, and a method for etching the multi-metal film using the same.

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

A first aspect of the present disclosure is an etchant composition, comprising about 35 wt% to about 70 wt% phosphoric acid, based on the total weight of the etchant composition; From about 0.5% to about 8% by weight of nitric acid; About 2% to about 20% acetic acid; About 0.5% to about 10% by weight of the fluorine-containing compound; And a residual amount of water.

In the conventional phosphoric acid-based copper etchant, the etching rate of copper was very fast and difficult to control due to nitric acid, which was the main oxidant. In addition, even when an organic-inorganic additive was added to phosphoric acid in order to control the copper etching rate, a great effect could not be obtained. In the present invention, the Cu / Ti dual structure can be patterned by effectively controlling the etching rate of copper by using a phenomenon in which oxidant, another oxidant, lowers the etching rate of copper instead of an organic inorganic additive that is a conventional corrosion inhibitor.

A second aspect of the present invention provides a method of multi-metal film etch comprising the steps of:

Forming a photoresist film having a predetermined pattern on a multi-metal film deposited on a substrate;

Forming a metal wiring pattern by using the photoresist film as a mask and etching the multi-metal film using an etchant composition; And

Removing the photoresist film.

Wherein the etchant composition comprises about 35% to about 70% by weight phosphoric acid, relative to its total weight; About 0.5% to about 8% nitric acid; About 2% to about 20% acetic acid; About 0.5% to about 10% by weight of the fluorine-containing compound; And residual water.

When the etching process is performed using the etching composition of the present invention, the problems caused by the conventional etching solution of hydrogen peroxide series can be effectively solved. Specifically, the conventional hydrogen peroxide-based etching solution is required to excessively use the pure water of the etching solution, accordingly, the amount of the waste liquid also increases, and when the hydrogen peroxide-based etching solution contains a metal, the hydrogen peroxide decomposition reaction by the metal proceeds The etchant had a problem that it is difficult to maintain a stable and thereby there is a risk of explosion, the etchant composition of the present application does not exhibit such a problem.

In addition, when using the etchant composition of the present application, excellent etching characteristics can be expected with only one wet etching process for the Cu / Ti double layer. Specifically, in the case of performing the etching process using the etchant composition according to the present application, the etching end time (EPD, End Point Detection), etching rate (Etch rate), etching loss (CD skew), step length, And etching characteristics such as a taper angle may be improved at the same time. In addition, the etchant composition according to the present invention has a relatively long life-time, which is economical and advantageous for commercial use.

The etchant composition of the present application may not be used only for etching the Cu / Ti double layer, but may be used for etching various multimetal layers. The multi-metal film may include one or more layers of Cu or Cu-alloy, and one or more layers of Ti or Ti-alloy, but is not limited thereto. In addition, the etchant composition of the present disclosure may be applied to various multi-metal films. have.

The etchant composition and the etching method using the etchant composition of the present invention can be effectively used in a process of patterning a conductive film used for a TFT (Thin Film Transistor), an active matrix OLED, or a touch sensor panel of a flat panel display, for example. But is not limited to, and can be widely used in various industrial fields requiring etching.

FIG. 1 is a polarization curve showing electrochemical behavior of Cu and Ti when an etching solution is treated to a Cu / Ti double layer according to one embodiment of the present application. Specifically, FIG. 1A is an etching solution containing no fluorine-containing compound. 1b is a case where an etching solution containing a fluorine-containing compound is treated.
FIG. 2 is a graph showing etching rates of Cu and Ti when an etching solution is treated to a Cu / Ti double layer according to one embodiment of the present application, and the etching rate according to the content of a fluorine-containing compound included in the etching solution is shown in FIG. Is a graph that shows how.
FIG. 3 is a graph illustrating treatment by treating an etching solution on a Cu / Ti double layer and measuring a galvanic current value according to an embodiment of the present application, wherein the galvanic current value is changed according to the content of a fluorine-containing compound included in the etching solution. Here is a graph showing how it changes.
FIG. 4 is a SEM photograph of a Cu / Ti double layer etched using an etchant according to an example or comparative example of the present application. More specifically, FIGS. 4A and 4B correspond to Examples 1 and 2, respectively. 4C to 4T show the use of the etchant corresponding to Comparative Examples 1 to 18, respectively.
FIG. 5 is a high magnification SEM photograph of a Cu / Ti double layer etched using an etchant according to a comparative example of the present application. More specifically, FIGS. 5a and 5b each illustrate an etchant corresponding to Comparative Example 5 and Comparative Example 14. If used.
6 is an energy dispersive spectroscopy (EDS) graph of a Cu / Ti double layer etched using an etchant according to Comparative Example 14 of the present application.
FIG. 7 is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Example 1 of the present application, and shows a degree of step length generation. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is located "on" another member, this includes not only when one member is in contact with another member but also when another member exists between the two members.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The terms "about "," substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure. The word " step (or step) "or" step "used to the extent that it is used throughout the specification does not mean" step for.

Throughout this specification, the term "combination of these" included in the expression of the makushi form means one or more mixtures or combinations selected from the group consisting of constituents described in the expression of the makushi form, wherein the constituents It means to include one or more selected from the group consisting of.

Hereinafter, with reference to the accompanying drawings will be described embodiments and embodiments of the present application;

A first aspect of the present disclosure is an etchant composition, comprising about 35 wt% to about 70 wt% phosphoric acid, based on the total weight of the etchant composition; From about 0.5% to about 8% by weight of nitric acid; About 2% to about 20% acetic acid; About 0.5% to about 10% by weight of the fluorine-containing compound; And a residual amount of water.

According to one embodiment of the present disclosure, more preferably, the etchant composition comprises about 50% to about 65% by weight phosphoric acid, based on the total weight thereof; About 1% to about 3% nitric acid; About 12% to about 16% acetic acid; About 1% to about 4% by weight of the fluorine-containing compound; And residual water, but is not limited thereto.

Referring to the weight ratio of the etchant composition, the etchant composition according to the first aspect of the present application can be seen as an etchant based on inorganic acids such as phosphoric acid, nitric acid, and acetic acid, which includes a small amount of the inorganic acid. It is distinguished from an etchant that serves as a simple auxiliary oxidant. In addition, the etchant composition may contain the above-mentioned phosphoric acid, nitric acid, acetic acid, fluorine-containing compounds, and materials other than water as necessary. However, when the etching solution composition further includes a chlorine-containing compound, copper residue may occur as CuCl or CuCl ₂ is formed around the pattern as a by-product, and thus, the angle of inclination is excessively large. In the etching solution composition, it is preferable not to further include a chlorine compound, but is not limited thereto.

In the etchant composition, phosphoric acid (H ₃ PO ₄ ) serves as a basic oxidizing agent, preferably about 35% to about 70% by weight based on the total weight of the composition, but is not limited thereto. When phosphoric acid is included in the etchant composition less than about 35% by weight, Cu etching may not occur, or the water content may be excessively increased to cause problems of Cu overetching, but is not limited thereto. On the other hand, when phosphoric acid is contained in the etchant composition in excess of about 70% by weight, the Cu etching rate is excessively increased, which may cause problems of Cu overetching, and spray spray becomes difficult due to an increase in the viscosity of the etchant. There may be a problem, but is not limited thereto. On the other hand, the higher the ratio of pure phosphoric acid in total phosphoric acid is, the better.

In the etchant composition, nitric acid (HNO ₃ ) plays a role of Cu oxidant, and is preferably included in about 0.5% to about 8% by weight based on the total weight of the composition, but is not limited thereto. When nitric acid is included in the etchant composition in less than about 0.5% by weight, it may be difficult to obtain a stable pattern by reducing the Cu and Ti etching rates, but is not limited thereto. On the other hand, when nitric acid is included in the etchant composition in excess of about 8% by weight, the Cu etching rate may be excessively increased, thereby causing problems of Cu overetching, and the galvanic phenomenon of Cu and Ti may be promoted to increase the step width (Step length) value may increase rapidly, but is not limited thereto.

In the etchant composition, acetic acid (CH ₃ COOH) plays a role of the galvanic development control solution of Cu and Ti, it is preferably included in about 2% to about 20% by weight relative to the total weight of the composition, but is not limited thereto. It doesn't happen. When acetic acid is included in the etchant composition in less than about 2% by weight, the galvanic phenomenon of Cu and Ti may be intensified, and the step length may increase sharply, and residue may be partially generated due to the increase in Cu etching rate. The possibilities may be large, but are not limited thereto. On the other hand, when acetic acid is included in more than about 20% by weight in the etchant composition may have a problem that the straightness of the pattern is poor, but is not limited thereto.

In this regard, when acetic acid is included in the etchant composition, the copper oxide film (CuO ₂ ) formed on the Cu surface by the phosphoric acid treatment is dissolved, thereby increasing the Cu etching rate. On the other hand, when acetic acid is contained in the etchant composition, the titanium oxide film (TiO ₂ ) formed on the Ti surface by the phosphoric acid is grown, the etching rate of Ti can be reduced. As the content of acetic acid contained in the etchant composition is increased to a certain level, the entire galvanic phenomenon changes due to the above-mentioned actions, and the effect of decreasing the step length and etching loss (CD skew) Can be obtained.

In the etchant composition, the fluorine-containing compound may be used to remove residues in the form of small particles, which may be caused as a result of etching and remain on a glass substrate or a lower layer, which may cause pixel defects. It doesn't happen.

For example, the fluorine-containing compound is preferably included, but is not limited to about 0.5% to about 10% by weight relative to the total weight of the composition. When the fluorine-containing compound is included in the composition in less than about 0.5% by weight, the etching rate of Ti is greatly reduced, and residues may be generated in the Cu film and the Ti film, and the fluorine-containing compound is 10% by weight in the composition. If it is included in excess, there is a problem that the damage to the glass substrate is intensified to cause an undercut or cause a short circuit, but is not limited thereto.

According to an embodiment of the present disclosure, the fluorine-containing compound includes at least one of HF, NaF, NaF ₂ , NH ₄ F, NH ₄ HF ₂ , H ₂ SiF ₆ , Na ₂ SiF ₆ , and KHF ₂ . May be, but is not limited thereto.

According to one embodiment of the present application, the etchant composition may include two or more different kinds of the fluorine-containing compound, but is not limited thereto. When the etchant composition contains one type of fluorine-containing compound, the stability thereof is poor, the etching of the glass substrate may be severe, and precise patterning may be difficult. Therefore, two or more types of fluorine-containing compounds may be mixed and used. It may be preferable, but is not limited thereto.

However, for example, when a mixture of fluorine-containing compounds of different types is used in pure HF, the problem that the etching of the glass substrate may be severe may not be solved. Accordingly, in order to prevent all of the expected problems while improving the etching characteristics, for example, NH ₄ HF ₂ and NH ₄ F can be used in combination, in which case the content of NH ₄ HF ₂ and NH ₄ F It is preferably 1% by weight or less, but is not limited thereto.

With respect to the etchant composition of the present disclosure comprising a fluorine-containing compound, FIGS. 1 to 3 of the present application show the effect.

First, FIG. 1 is a polarization curve showing electrochemical behavior of Cu and Ti when an etching solution is treated to a Cu / Ti double layer according to one embodiment of the present application. Specifically, FIG. 1A does not include a fluorine-containing compound. FIG. 1B illustrates a case where an etchant containing a fluorine-containing compound is treated.

In general, since Ti has a dense oxide film on the surface, it shows a passivation phenomenon that does not melt well in most aqueous solutions. Thus, even in the case of FIG. It will not melt. However, if the etching solution contains a fluorine-containing compound, the oxide film is destroyed by the fluorine ions, so that the Ti portion having a dense oxide film on the surface can also be rapidly melted. In this regard, referring to FIG. 1B, after the fluorine-containing compound is added on the polarization curve, the corrosion potential of Ti is moved in the activation direction, and the corrosion current corresponding to the corrosion potential also increases rapidly.

On the other hand, the etching behavior change of Ti depending on whether or not the fluorine-containing compound is included in the etchant has a great influence on the galvanic phenomenon generated when the Cu and Ti are bonded. In this regard, referring to FIG. 1A, in the case of treating an etchant containing no fluorine-containing compound, Ti plays a role of cathode, Cu plays an anode role, and Ti promotes corrosion of Cu. Accordingly, Ti may not melt and remain a residue while Cu may be excessively etched. On the other hand, referring to Figure 1b, when treating the etching solution containing a fluorine-containing compound, as the fluorine ions destroy the oxide film of Ti, Ti can be melted well, thereby changing the role of Ti from cathode to anode. . As a result, Ti can be further melted and a Cu / Ti film having an appropriate inclination angle after etching can be obtained. That is, when the fluorine-containing compound is included, the Cu / Ti double layer can also be efficiently etched using a phosphoric acid-based etching solution such as the etching solution of the present invention.

Next, FIG. 2 is a graph showing etching rates of Cu and Ti when an etching solution is treated to a Cu / Ti double layer according to an embodiment of the present application, and according to the content of the fluorine-containing compound included in the etching solution. It is a graph showing how the etching rate changes.

Fluoride ions are generally known to improve the corrosion rate of metals, but the experiments conducted in the present application confirmed that the increase in the concentration of fluorine ions in the phosphate-based etching solution containing nitric acid decreases the etching rate of Cu. The etching rate of Cu is known to be influenced by the hydration film, which is an etching byproduct generated on the Cu surface during etching. In general, when treating a phosphate-based etching solution containing nitric acid, Cu is etched at a rapid rate due to the fact that the Cu (OH) ₂ film formed on the surface has a porous structure and does not cover all of the Cu exposed to the etching solution. do. However, when fluorine ions are added, instead of the Cu (OH) ₂ film having a porous structure, a dense CuF ₂ · nH ₂ O film is formed, and the CuF ₂ · nH ₂ O film suppresses mass transfer. Etch rate is lowered.

That is, the Cu overetching phenomenon, which was a big problem of the conventional phosphoric acid-based etching solution, can be effectively solved by supplying fluorine ions by adding a fluorine-containing compound to the etching solution according to the present application. More specifically, when the phosphate-based etchant contains fluorine ions, since the etching rate of Ti is improved and the etching rate of Cu is lowered, the fluorine ions serve as a corrosion inhibitor that suppresses over-etching of Cu. can see.

Next, FIG. 3 is a graph illustrating treatment by treating an etching solution on a Cu / Ti double layer and measuring a galvanic current value according to an embodiment of the present application, wherein the galvanic is based on the content of a fluorine-containing compound included in the etching solution. This graph shows how the current value changes.

In this case, since Cu is held as an anode, it means that the larger the galvanic current value, the more the Cu is excessively etched due to the galvanic phenomenon with Ti. Referring to the graph of FIG. 3, it can be seen that as the fluorine-containing compound is added to the etchant, the galvanic current value decreases, from which the over-etching of Cu is effectively suppressed by the addition of the fluorine-containing compound. .

That is, by referring to FIGS. 1 to 3, it can be confirmed that the etching characteristics of the etching solution composition of the present application include fluorine-containing compounds.

In the etchant composition, the water content also plays an important role in copper etching, and the phosphorus acid, nitric acid, acetic acid, fluorine-containing compound and the like are included in the remaining amount after etching. In general, when an excessive amount of water is included in the etchant, the etching rate of Cu is increased, and the step length may be increased by promoting the galvanic phenomenon of the Cu film and the Ti film.

According to one embodiment of the present application, the etchant composition may include, but is not limited to, about 1 wt% to about 10 wt% of a sulfate compound based on the total weight thereof. For example, when the sulphate compound is not added, Cu overetching may occur, and thus the Cu pattern may be seriously damaged after etching. However, the problem may be solved by adding the sulphate compound. In addition, by adding the sulfate compound, it is possible to improve etching characteristics such as etching loss (CD skew) and taper angle (Taper angle). For example, when the sulfate compound is included in about 1% by weight to about 7% by weight, the Cu etch rate is increased and the Ti etch rate is not significantly affected. When the sulphate compound is included at least 7 wt%, the Ti etch rate may decrease. And, when included in about 10% by weight or more, but the Cu etching rate is also lowered may cause a problem of lack of etching, but is not limited thereto.

According to one embodiment of the present application, the etchant composition may be more preferably containing about 3% to about 7% by weight of the sulfate compound relative to the total weight thereof, but is not limited thereto.

According to one embodiment of the present application, the sulfate compound may include at least one of an ammonium salt of sulfuric acid, an alkali metal salt of sulfuric acid, and an alkaline earth metal salt of sulfuric acid, but is not limited thereto. For example, the sulfate compound may include at least one of ammonium sulfate, ammonium persulfate, lithium sulfate, lithium persulfate, sodium sulfate, sodium persulfate, potassium sulfate, potassium persulfate, calcium sulfate, and calcium persulfate. However, the present invention is not limited thereto.

For example, the etchant compositions herein may additionally include, but are not limited to, conventional additives to improve etch characteristics. The conventional additives may include, for example, a surfactant, an etch control agent, but are not limited thereto.

For example, in order to obtain a smooth taper angle by controlling the etching rate of a Cu film, HEDP (1-Hydroxyethylidene diphosphonic acid, C ₂ H ₈ O ₇ P ₂ ), which is a representative Cu corrosion inhibitor, as an additive, or Aminotetrazole (ATTE, CH ₃ N ₅ ) may be further included, but is not limited thereto.

In addition, for the purpose of reducing the galvanic phenomenon, as an additive, a heterocyclic amine compound, for example, imidazole (Imidazole, C ₃ H ₄ N ₂ ), aminotetrazole (CH ₃ N ₅ ), ascorb Ascorbic acid (C ₆ H ₈ O ₆ ), Sodium dihydrogen phosphate (NaH ₂ PO ₄ ), Aminodiacetic acid (C ₄ H ₇ NO ₄ ), Disodium hydrogen phosphate ( Disodium hydrogen phosphate, Na ₂ HPO ₄ ) and the like can be used, but is not limited thereto. For example, when the imidazole is used as an additive, etching properties such as CD skew and step length can be improved while affecting the etching rate, but the present invention is not limited thereto.

According to one embodiment of the present application, the etchant composition may be used to etch a multi-metal film, but is not limited thereto.

According to one embodiment of the present application, the multi-metal film may include one or more layers of Cu or Cu-alloy, and one or more layers of Ti or Ti-alloy, but is not limited thereto. For example, the Ti-alloy includes at least one of Ti and Ta, V, Nb, Mg, Fe, Cr, Co, Ni, Cu, Si, Al, Ga, Ge, C, O, and N. May be, but is not limited thereto. In addition, for example, the Cu-alloy may include at least one of Cu, Mg, Mo, Zn, Sn, Fe, Al, Be, Co, Ni, Ti, and Mn, but is not limited thereto. .

For example, the multi-metal film is formed by being deposited on a substrate, and a photoresist film may be formed on the multi-metal film, but the present invention is not limited thereto. For example, the substrate, the multi-metal film, and the photoresist film may be formed by forming a Ti or Ti-alloy layer on the substrate, forming a Cu or Cu-alloy layer on the Ti or Ti- And a photoresist film is formed on the Cu or Cu-alloy layer. However, the present invention is not limited thereto. In this case, the substrate may be, for example, a glass substrate for a TFT (Thin Film Transistor) LCD, a metal thin film substrate for a flexible display, or a plastic substrate, but is not limited thereto.

According to one embodiment of the invention, the thickness ratio of at least one layer of the Cu or Cu-alloy and at least one layer of the Ti or Ti-alloy may be about 5: 1 to about 300: 1, But is not limited thereto. When the thickness ratio is less than about 5: 1, the galvanic phenomenon is promoted and the step length value may be increased, but the present invention is not limited thereto. For example, at least one layer of the Cu or Cu-alloy may be of a thickness of from about 2,500 A to about 15,000 A, but is not limited thereto. Also, for example, the at least one layer of Ti or Ti-alloy may be of a thickness of from about 50 A to about 500 A, but is not limited thereto.

According to one embodiment of the disclosure, the temperature of the etchant composition may be from about 35 ° C to about 70 ° C, but is not limited thereto. When the etchant composition is less than about 35 ° C, the value of the CD skew and the step length may be nonuniform, and when the etchant composition is more than about 70 ° C, an overeating phenomenon may occur , But is not limited thereto.

For example, the etchant composition of the first aspect of the present invention may be usefully used in the process of patterning a conductive film used in a TFT (Thin Film Transistor), an active matrix OLED, or a touch sensor panel of a flat panel display, no.

A second aspect of the present invention provides a method of multi-metal film etch comprising the steps of:

Forming a photoresist film having a predetermined pattern on a multi-metal film deposited on a substrate;

Forming a metal wiring pattern by using the photoresist film as a mask and etching the multi-metal film using an etchant composition; And

Removing the photoresist film.

Wherein the etchant composition comprises about 35% to about 70% by weight phosphoric acid, relative to its total weight; From about 0.5% to about 8% by weight of nitric acid; About 2% to about 20% acetic acid; About 0.5% to about 10% by weight of the fluorine-containing compound; And residual water.

According to one embodiment of the present disclosure, more preferably, the etchant composition comprises about 50% to about 65% by weight phosphoric acid, based on the total weight thereof; About 1% to about 3% nitric acid; About 12% to about 16% acetic acid; About 1% to about 4% by weight of the fluorine-containing compound; And residual water, but is not limited thereto.

Referring to the weight ratio of the etchant composition, the etchant composition used in the etching method of the second aspect of the present application can be seen as an etchant based on inorganic acids such as phosphoric acid, nitric acid, and acetic acid, which is the inorganic acid. It is distinguished from the etchant that contains a small amount of and serves as a simple auxiliary oxidant. In addition, the etchant composition may contain the above-mentioned phosphoric acid, nitric acid, acetic acid, fluorine-containing compounds, and materials other than water as necessary. However, when the etchant composition further includes a chlorine-containing compound, as CuCl ₂ is formed as a by-product, the amount of precipitates is increased and the inclination angle is excessively large. It is preferable not to further include a chlorine compound, but is not limited thereto.

In the etchant composition, phosphoric acid (H ₃ PO ₄ ) serves as a basic oxidizing agent, it is preferably included in about 35% to about 80% by weight relative to the total weight of the composition, but is not limited thereto. When phosphoric acid is included in the etchant composition less than about 35% by weight, Cu etching may not occur, or the water content may be excessively increased to cause problems of Cu overetching, but is not limited thereto. On the other hand, when phosphoric acid is contained in the etchant composition in excess of about 80% by weight, the Cu etching rate is excessively increased, which may cause problems of Cu overetching, and spray spray becomes difficult due to an increase in the viscosity of the etchant. There may be a problem, but is not limited thereto. On the other hand, the higher the ratio of pure phosphoric acid in total phosphoric acid is, the better.

In the etchant composition, nitric acid (HNO ₃ ) plays a role of Cu oxidant, and is preferably included in about 0.5% to about 8% by weight based on the total weight of the composition, but is not limited thereto. When nitric acid is included in the etchant composition in less than about 0.5% by weight, it may be difficult to obtain a stable pattern by reducing the Cu and Ti etching rates, but is not limited thereto. On the other hand, when nitric acid is included in the etchant composition in excess of about 8% by weight, the Cu etching rate may be excessively increased, thereby causing problems of Cu overetching, and the galvanic phenomenon of Cu and Ti may be promoted to increase the step width (Step There may be a problem that length) is increased rapidly, but is not limited thereto.

In the etchant composition, acetic acid (CH ₃ COOH) plays a role of the galvanic development control solution of Cu and Ti, it is preferably included in about 2% to about 20% by weight relative to the total weight of the composition, but is not limited thereto. It doesn't happen. When acetic acid is included in the etchant composition in less than about 2% by weight, the galvanic phenomenon of Cu and Ti may be intensified, and the step length may increase sharply, and residue may be partially generated due to the increase in Cu etching rate. The possibilities may be large, but are not limited thereto. On the other hand, when acetic acid is included in more than about 20% by weight in the etchant composition may have a problem that the straightness of the pattern is poor, but is not limited thereto.

In this regard, when acetic acid is included in the etchant composition, the copper oxide film (CuO ₂ ) formed on the Cu surface by the phosphoric acid treatment is dissolved, thereby increasing the Cu etching rate. On the other hand, when acetic acid is contained in the etchant composition, the titanium oxide film (TiO ₂ ) formed on the Ti surface by the phosphoric acid is grown, the etching rate of Ti can be reduced. As the content of acetic acid contained in the etchant composition is increased to a certain level, the entire galvanic phenomenon changes due to the above-mentioned actions, and the effect of decreasing the step length and etching loss (CD skew) Can be obtained.

In the etchant composition, the fluorine-containing compound may be used to remove residues in the form of small particles, which may be caused as a result of etching and remain on a glass substrate or a lower layer, which may cause pixel defects. It doesn't happen.

For example, the fluorine-containing compound is preferably included, but is not limited to about 0.5% to about 10% by weight relative to the total weight of the composition. When the fluorine-containing compound is included in the composition at less than about 0.5% by weight, the etching rate of Ti may be greatly reduced, resulting in residues in the Cu film and the Ti film. When included in more than%, there is a problem that the damage to the glass substrate is intensified to cause an undercut or cause a short circuit, but is not limited thereto.

According to an embodiment of the present disclosure, the fluorine-containing compound includes at least one of HF, NaF, NaF ₂ , NH ₄ F, NH ₄ HF ₂ , H ₂ SiF ₆ , Na ₂ SiF ₆ , and KHF ₂ . May be, but is not limited thereto.

According to one embodiment of the present application, the etchant composition may include two or more different kinds of the fluorine-containing compound, but is not limited thereto. When the etchant composition contains one type of fluorine-containing compound, the stability thereof is poor, the etching of the glass substrate may be severe, and precise patterning may be difficult. Therefore, two or more types of fluorine-containing compounds may be mixed and used. It may be preferable, but is not limited thereto.

However, for example, when a mixture of fluorine-containing compounds of different types is used in pure HF, the problem that the etching of the glass substrate may be severe may not be solved. Accordingly, in order to prevent all of the expected problems while improving the etching characteristics, for example, NH ₄ HF ₂ and NH ₄ F can be used in combination, in which case the content of NH ₄ HF ₂ and NH ₄ F It is preferably 1% by weight or less, but is not limited thereto.

With respect to the etchant composition of the present disclosure comprising a fluorine-containing compound, FIGS. 1 to 3 of the present application show the effect.

First, FIG. 1 is a polarization curve showing electrochemical behavior of Cu and Ti when an etching solution is treated to a Cu / Ti double layer according to one embodiment of the present application. Specifically, FIG. 1A does not include a fluorine-containing compound. FIG. 1B illustrates a case where an etchant containing a fluorine-containing compound is treated.

In general, since Ti has a dense oxide film on the surface, it shows a passivation phenomenon that does not melt well in most aqueous solutions. Thus, even in the case of FIG. It will not melt. However, if the etching solution contains a fluorine-containing compound, the oxide film is destroyed by the fluorine ions, so that the Ti portion having a dense oxide film on the surface can also be rapidly melted. In this regard, referring to FIG. 1B, after the fluorine-containing compound is added on the polarization curve, the corrosion potential of Ti is moved in the activation direction, and the corrosion current corresponding to the corrosion potential also increases rapidly.

On the other hand, the etching behavior change of Ti depending on whether or not the fluorine-containing compound is included in the etchant has a great influence on the galvanic phenomenon generated when the Cu and Ti are bonded. In this regard, referring to FIG. 1A, in the case of treating an etchant containing no fluorine-containing compound, Ti plays a role of cathode, Cu plays an anode role, and Ti promotes corrosion of Cu. Accordingly, Ti may not melt and remain a residue while Cu may be excessively etched. On the other hand, referring to Figure 1b, when treating the etching solution containing a fluorine-containing compound, as the fluorine ions destroy the oxide film of Ti, Ti can be melted well, thereby changing the role of Ti from cathode to anode. . As a result, Ti can be further melted and a Cu / Ti film having an appropriate inclination angle after etching can be obtained. That is, when the fluorine-containing compound is included, the Cu / Ti double layer can also be efficiently etched using a phosphoric acid-based etching solution such as the etching solution of the present invention.

Next, FIG. 2 is a graph showing etching rates of Cu and Ti when an etching solution is treated to a Cu / Ti double layer according to an embodiment of the present application, and according to the content of the fluorine-containing compound included in the etching solution. It is a graph showing how the etching rate changes.

Fluoride ions are generally known to improve the corrosion rate of metals, but the experiments conducted in the present application confirmed that the increase in the concentration of fluorine ions in the phosphate-based etching solution containing nitric acid decreases the etching rate of Cu. The etching rate of Cu is known to be influenced by the hydration film, which is an etching byproduct generated on the Cu surface during etching. In general, when treating a phosphate-based etching solution containing nitric acid, Cu is etched at a rapid rate due to the fact that the Cu (OH) ₂ film formed on the surface has a porous structure and does not cover all of the Cu exposed to the etching solution. do. However, when fluorine ions are added, instead of the Cu (OH) ₂ film having a porous structure, a dense CuF ₂ · nH ₂ O film is formed, and the CuF ₂ · nH ₂ O film suppresses mass transfer. Etch rate is lowered.

That is, the Cu overetching phenomenon, which was a big problem of the conventional phosphoric acid-based etching solution, can be effectively solved by supplying fluorine ions by adding a fluorine-containing compound to the etching solution according to the present application. More specifically, when the phosphate-based etchant contains fluorine ions, since the etching rate of Ti is improved and the etching rate of Cu is lowered, the fluorine ions serve as a corrosion inhibitor that suppresses over-etching of Cu. can see.

Next, FIG. 3 is a graph illustrating treatment by treating an etching solution on a Cu / Ti double layer and measuring a galvanic current value according to an embodiment of the present application, wherein the galvanic is based on the content of a fluorine-containing compound included in the etching solution. This graph shows how the current value changes.

In this case, since Cu is held as an anode, it means that the larger the galvanic current value, the more the Cu is excessively etched due to the galvanic phenomenon with Ti. Referring to the graph of FIG. 3, it can be seen that as the fluorine-containing compound is added to the etchant, the galvanic current value decreases, from which the over-etching of Cu is effectively suppressed by the addition of the fluorine-containing compound. .

That is, by referring to FIGS. 1 to 3, it can be confirmed that the etching characteristics of the etching solution composition of the present application include fluorine-containing compounds.

In the etching liquid composition, water also plays a role of improving the etching of copper, and the phosphoric acid, nitric acid, acetic acid, fluorine-containing compound and the like are included in the remaining amount after the etching solution. In general, when an excessive amount of water is included in the etchant, the etching rate of Cu is increased, and the step length may be increased by promoting the galvanic phenomenon of the Cu film and the Ti film.

According to one embodiment of the present application, the etchant composition may include, but is not limited to, about 1 wt% to about 10 wt% of a sulfate compound based on the total weight thereof. For example, when the sulphate compound is not added, Cu overetching may occur, and thus the Cu pattern may be seriously damaged after etching. However, the problem may be solved by adding the sulphate compound. In addition, by adding the sulfate compound, it is possible to improve etching characteristics such as etching loss (CD skew) and taper angle (Taper angle). For example, when the sulfate compound is included in about 1% by weight to about 7% by weight, the Cu etch rate is increased and the Ti etch rate is not significantly affected. When the sulphate compound is included at least 7 wt%, the Ti etch rate may decrease. And, when included in about 10% by weight or more, but the Cu etching rate is also lowered may cause a problem of lack of etching, but is not limited thereto.

According to one embodiment of the present application, the etchant composition may be more preferably containing about 3% to about 7% by weight of the sulfate compound relative to the total weight thereof, but is not limited thereto.

According to one embodiment of the present application, the sulfate compound may include at least one of an ammonium salt of sulfuric acid, an alkali metal salt of sulfuric acid, and an alkaline earth metal salt of sulfuric acid, but is not limited thereto. For example, the sulfate compound may include at least one of ammonium sulfate, ammonium persulfate, lithium sulfate, lithium persulfate, sodium sulfate, sodium persulfate, potassium sulfate, potassium persulfate, calcium sulfate, and calcium persulfate. However, the present invention is not limited thereto.

For example, the etchant compositions herein may additionally include, but are not limited to, conventional additives to improve etch characteristics. The conventional additives may include, for example, a surfactant, an etch control agent, but are not limited thereto.

For example, in order to obtain a smooth taper angle by controlling the etching rate of a Cu film, HEDP (1-Hydroxyethylidene diphosphonic acid, C ₂ H ₈ O ₇ P ₂ ), which is a representative Cu corrosion inhibitor, as an additive, or Aminotetrazole (ATTE, CH ₃ N ₅ ) may be further included, but is not limited thereto.

In addition, for the purpose of reducing the galvanic phenomenon, as an additive, a heterocyclic amine compound, for example, imidazole (Imidazole, C ₃ H ₄ N ₂ ), aminotetrazole (CH ₃ N ₅ ), ascorb Ascorbic acid (C ₆ H ₈ O ₆ ), Sodium dihydrogen phosphate (NaH ₂ PO ₄ ), Aminodiacetic acid (C ₄ H ₇ NO ₄ ), Disodium hydrogen phosphate ( Disodium hydrogen phosphate, Na ₂ HPO ₄ ) and the like can be used, but is not limited thereto. For example, when the imidazole is used as an additive, the etching characteristics such as CD skew and step length values may be improved without affecting the etching rate, but are not limited thereto. .

According to one embodiment of the present application, the multi-metal film may include one or more layers of Cu or Cu-alloy, and one or more layers of Ti or Ti-alloy, but is not limited thereto. For example, the Ti-alloy may include at least one of Ti and W, Mo, Ta, and Nb, but is not limited thereto. In addition, for example, the Cu-alloy may include at least one of Cu, Mg, Mo, and Mn, but is not limited thereto.

For example, the multi-metal film is formed by being deposited on a substrate, and a photoresist film may be formed on the multi-metal film, but the present invention is not limited thereto. For example, the substrate, the multi-metal film, and the photoresist film may be formed by forming a Ti or Ti-alloy layer on the substrate, forming a Cu or Cu-alloy layer on the Ti or Ti- And a photoresist film is formed on the Cu or Cu-alloy layer. However, the present invention is not limited thereto. In this case, the substrate may be, for example, a glass substrate for a thin film transistor (TFT) LCD, a metal thin film substrate for a flexible display, or a plastic substrate, but is not limited thereto.

According to one embodiment of the invention, the thickness ratio of at least one layer of the Cu or Cu-alloy and at least one layer of the Ti or Ti-alloy may be about 5: 1 to about 300: 1, But is not limited thereto. When the thickness ratio is less than about 5: 1, the galvanic phenomenon is promoted and the step length value may be increased, but the present invention is not limited thereto. For example, at least one layer of the Cu or Cu-alloy may be of a thickness of from about 2,500 A to about 15,000 A, but is not limited thereto. Also, for example, the at least one layer of Ti or Ti-alloy may be of a thickness of from about 50 A to about 500 A, but is not limited thereto.

According to one embodiment of the present disclosure, at least one layer of the Cu or Cu-alloy may be a gate electrode or a source / drain electrode, but is not limited thereto.

According to one embodiment of the present disclosure, etching the multi-metal film may include, but is not limited to, being performed at a temperature of about 35 ° C to about 70 ° C. When the etchant composition is less than about 35 ° C, the value of the CD skew and the step length may be nonuniform, and when the etchant composition is more than about 70 ° C, an overeating phenomenon may occur , But is not limited thereto.

According to one embodiment of the disclosure, the etchant composition may include, but is not limited to, spraying for a period of from about 30 seconds to about 300 seconds.

For example, the etching method of the second aspect of the present invention can be advantageously used in a process of patterning a conductive film used in a TFT (Thin Film Transistor), an active matrix OLED, or a touch sensor panel of a flat panel display, no.

Regarding the etchant of the first aspect of the present application, and the etching method of the second aspect of the present application, FIGS. 4 to 7 herein provide more specific data related to the examples and comparative examples of the present application described below.

Hereinafter, the etching liquid composition of the present application will be described in more detail using Examples and Comparative Examples, but the present application is not limited thereto. In addition, although a particularly preferred etchant composition is referred to as an "example" and other etchant compositions as a "comparative example", the present application is not limited thereto, and the etchant composition referred to as the "comparative example" is also referred to herein. It is included in the scope of the invention.

[ Example ]

In the Examples of the present application, etching was performed using the etchant composition of Examples 1 and 2, and Comparative Examples 1 to 18, and the etching characteristics of each case were analyzed.

In all Examples and Comparative Examples of the present application, the etching was performed in common according to the following [Experimental Example], and specific compounds and composition ratios included in the etchant according to each Example or Comparative Example are described in [Experimental Example]. This is described in detail later.

Experimental Example

Prepare a specimen on which a Cu / Ti double layer is deposited on a 0.7 mm thick glass substrate, and place the etchant according to each example or comparative example in a spray etching apparatus (manufactured by FNS Tech), and then adjust the temperature to 40 ° C. The specimens were warmed and etched when the temperature reached 40 ± 0.5 ° C. During etching, the etchant was sprayed at 0.1 MPa toward the specimen.

The total etching time was performed by adding 100% of the over etch based on the end point detection (EPD), and when the final data is arranged, the value of the end time (EPD; It was recorded in terms of the etching rate (Etch rate (Å / sec units)).

After performing the etching process, the specimen was removed from the etching experiment equipment, washed with deionized water, dried using a hot air drying apparatus, and the photoresist was removed using a photoresist stripper.

Then, using a scanning electron microscope (SEM; manufactured by TESCAN), one-sided etch loss (CD skew; Critical Dimension skew) value, one-sided step width (step length; difference in wiring width between Cu film and Ti film after etching; Cu film width- Ti film width) values, and whether or not residues occurred after etching were analyzed.

The smaller the CD skew value and the step length value are, the more preferable. In general, the CD skew value is 0.5 μm or less and the step length value is 0.2 μm or less. It can be seen that the etching was performed. It is also preferable that no residue is generated.

Hereinafter, specific compounds contained in the etchant according to each example or comparative example, the composition ratio thereof, and the results of the etching characteristic experiment were described.

Example  One

Compounds included in the etchant of Example 1 and their composition ratios were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (12.5 wt.%)].

As Example 1, the etching of the specimen using the etching solution having the above composition and the etching characteristics were measured. As a result, it was found that the taper angle of the Cu / Ti film was stable at about 60 °. Also hardly formed. In addition, the etching loss (CD skew) value was less than 0.4 μm showed a stable value.

In relation to Example 1, FIG. 4A of the present application is an SEM photograph of a Cu / Ti double layer etched using the etchant according to Example 1, and FIG. 7 is particularly etched using the etchant according to Example 1 In this case, it is a SEM photograph showing the degree of step length occurrence.

Example  2

The compound included in the etchant of Example 2 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NH ₄ F (0.5 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (14 wt.%)].

Examples of the fluorine-containing compound include HF, NaF, NaF ₂ , NH ₄ F, NH ₄ HF ₂ , H ₂ SiF ₆ , Na ₂ SiF ₆ , and KHF ₂ . In this case, since the stability thereof, the etching of the glass substrate may be severe, and precise patterning may be difficult, it may be preferable to use a mixture of two or more fluorine-containing compounds.

However, there is a problem that the etching of the glass substrate may be severe when using a mixture of different fluorine-containing compounds in pure HF.

Thus, in order to prevent all of the expected problems while improving the etching characteristics, in Example 2 was used by mixing NH ₄ HF ₂ and NH 4F.

Regarding Example 2, FIG. 4B of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Example 2. FIG.

Comparative example  One

Compounds included in the etchant of Comparative Example 1 and the respective composition ratios were as follows: [H ₃ PO ₄ (34 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (41.5 wt.%)].

In Comparative Example 1, etching was performed using an etchant containing about half the amount of phosphoric acid as compared to the etchant of Example 1. When phosphoric acid is included in the etching solution in an amount of 34% by weight or less as in Comparative Example 1, there was a problem that the Cu film was not etched, and thus it was difficult to obtain a desired pattern as an etching result.

Regarding Comparative Example 1, FIG. 4C of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 1. FIG.

Comparative example  2

Compounds included in the etchant of Comparative Example 2 and the respective composition ratios were as follows: [H ₃ PO ₄ (57 wt%) + HNO ₃ (7 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (13.5 wt.%)].

In Comparative Example 2, etching was performed using an etchant containing an excess of nitric acid 3 times or more than the etchant of Example 1. In the case where the etchant contains excessive nitric acid as in Comparative Example 2, the Cu film overetching is caused by increasing the etching rate of the Cu film portion, thereby increasing the step length value.

Regarding Comparative Example 2, FIG. 4D of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 1. FIG.

Comparative example  3

The compound included in the etchant of Comparative Example 3 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (0.5 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (14 wt.%).

In Comparative Example 3, etching was performed using an etchant containing about 1/4 of nitric acid as compared to the etchant of Example 1. As in Comparative Example 3, when the etchant contains less than 1% by weight of nitric acid, there is a problem in that stable patterning is difficult because both etching rates of the Cu film portion and the Ti film portion are reduced. Particularly, in the case where the etchant contains less than 0.5 wt% of nitric acid, the Cu film part is hardly etched, which causes difficulty in patterning.

Regarding Comparative Example 3, FIG. 4E of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 3.

Comparative example  4

The compound included in the etchant of Comparative Example 4 and the composition ratio of each were as follows: [H ₃ PO ₄ (60 wt%) + HNO ₃ (4 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (13.5 wt.%)].

In Comparative Example 4, the etching was performed using an etchant containing an excess of nitric acid more than twice as much as the etchant of Example 1. Although the degree was less than that of Comparative Example 2, as in Comparative Example 4, when the etchant contains an excess of 4 wt% or more of nitric acid, Cu film overetching is induced by increasing the etching rate of the Cu film portion. Accordingly, there is still a problem that the step length value increases.

Regarding Comparative Example 4, FIG. 4F of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Example 1. FIG.

Comparative example  5

The compound included in the etchant of Comparative Example 5 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (4 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (23 wt.%)].

In Comparative Example 5, etching was performed using an etchant containing about one third less acetic acid than the etchant of Example 1. As in Comparative Example 5, when the amount of acetic acid is less than 4% by weight in the etchant, there is a problem that the residue may be partially generated in the Cu film portion as the etching rate of the Cu film portion is increased.

Regarding Comparative Example 5, FIG. 4G of the present application is an SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 5, and FIG. 5A is an SEM photograph taken at a higher magnification than FIG. 4G. The white spots around the pattern were oxidized copper, indicating that a Cu residue remained.

Comparative example  6

The compound included in the etchant of Comparative Example 6 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (7 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (20 wt.%)].

In Comparative Example 6, etching was performed using an etchant containing about 1/2 of acetic acid as compared to the etchant of Example 1. When the acetic acid contains less than 7% by weight of acetic acid as in Comparative Example 6, there is a problem that local etching is performed as the etching rate of the Cu film portion decreases, thereby making it difficult to uniform patterning. Occurred.

Regarding Comparative Example 6, FIG. 4H of the present application is a SEM photograph of a Cu / Ti double layer etched using the etching solution according to Comparative Example 6.

Comparative example  7

Compounds included in the etchant of Comparative Example 7 and their respective composition ratios were as follows: [H ₃ PO ₄ (56 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (20 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (14 wt.%).

In Comparative Example 7, etching was performed using an etchant containing more acetic acid than the etchant of Example 1. As in Comparative Example 7, when the etchant contained an excess of 20% by weight or more of acetic acid, the etching rate was similar to that of Example 1, but the etching loss (CD skew) value and the step length (Step length) value were There was a problem of increasing. This was presumably because the excess of acetic acid in the etchant affected the galvanic phenomenon of the Cu / Ti film.

Regarding Comparative Example 7, FIG. 4I of the present application is a SEM photograph of a Cu / Ti double layer etched using the etching solution according to Comparative Example 7.

Comparative example  8

The compound included in the etchant of Comparative Example 8 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (0 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (14.5 wt.%)].

In Comparative Example 8, etching was performed using an etching solution containing less fluorine-containing compound than the etching solution of Example 1, in particular, only one type of fluorine-containing compound was used. In Comparative Example 8, the etching rate of the Ti film portion was greatly reduced, resulting in a problem that residues were generated in the Cu film and the Ti film.

Regarding Comparative Example 8, FIG. 4J of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 8.

Comparative example  9

Compounds included in the etchant of Comparative Example 9 and the respective composition ratios were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NH ₄ F (1 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + H ₂ O (13.5 wt.%).

In Comparative Example 9, the etching was performed using an etching solution containing more fluorine-containing compound than the etching solution of Example 2, specifically, the content of NH ₄ HF ₂ was the same but the content of NH ₄ F was about 2 times. The etchant containing a lot was used. In this case, a problem occurs that the lower glass substrate is excessively etched during the upper Cu / Ti film etching.

Regarding Comparative Example 9, FIG. 4K of the present application is a SEM photograph of a Cu / Ti double layer etched using the etching solution according to Comparative Example 9.

On the other hand, although not shown as data in this comparative example, when the total content of the fluorine-containing compound is contained in excess of 4% by weight or more, the glass substrate may be damaged by melting more than 3000 Å thickness per minute Accordingly, there is a problem that an undercut may occur in the glass substrate portion positioned below the Ti film, or a wiring short may occur due to this.

Comparative example  10

The compound included in the etchant of Comparative Example 10 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (0 wt.%) + H ₂ O (17.5 wt.%).

In Comparative Example 10, unlike the etching solution of Example 1, etching was performed using an etching solution containing no sulfate. In this case, the over-etching phenomenon of the Cu film portion occurs, causing a problem that the Cu film pattern after etching is seriously lost.

Regarding Comparative Example 10, FIG. 4L of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 10.

Comparative example  11

The compound included in the etchant of Comparative Example 11 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (1 wt.%) + H ₂ O (16.5 wt.%)].

In Comparative Example 11, etching was performed using an etching solution containing about 1/5 less sulfate than the etching solution of Example 1. In this case, compared with Comparative Example 10 in which no sulfate was used, the Cu film etching rate was decreased, and the Ti film etching rate was not significantly changed. Accordingly, the over-etching phenomenon of the Cu film portion was suppressed and the etching loss (CD skew) value and the step length value were also improved. However, compared with Example 1, a problem arises in that a step length value is large.

Regarding Comparative Example 11, FIG. 4M of the present application is a SEM photograph of a Cu / Ti double layer etched using the etching solution according to Comparative Example 11.

Comparative example  12

Compounds included in the etchant of Comparative Example 12 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (3 wt.%) + H ₂ O (14.5 wt.%)].

In Comparative Example 12, etching was performed using an etchant containing less than half the amount of sulfate compared to the etchant of Example 1. In this case, the Cu film etch rate was decreased and the Ti film etch rate was slightly increased compared to Comparative Example 10 in which no sulfate was used. Accordingly, the over-etching phenomenon of the Cu film portion was suppressed and the etching loss (CD skew) value and the step length value were also improved. However, compared with Example 1, a problem arises in that the step length value is still large.

Regarding Comparative Example 12, FIG. 4N of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 12.

Comparative example  13

The compound included in the etchant of Comparative Example 13 and the composition ratio of each were as follows: [H ₃ PO ₄ (60 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (7 wt.%) + H ₂ O (13.5 wt.%)].

In Comparative Example 13, the etching was performed using an etching solution containing a lot of sulfate compared to the etching solution of Example 1. As in Comparative Example 13, when the etching solution contained an excess of 7% by weight or more of the sulfate, the etching rate of the Cu film was greatly decreased, and the etching rate of Ti was significantly reduced, compared with the case of using a smaller amount of sulfate. Accordingly, there was a problem that Ti residues are generated after etching. Regarding Comparative Example 13, FIG. 4O of the present application is a SEM photograph of a Cu / Ti double layer etched using the etching solution according to Comparative Example 13.

Comparative example  14

The compound included in the etchant of Comparative Example 14 and the composition ratio of each were as follows: [H ₃ PO ₄ (57 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (10 wt.%) + H ₂ O (13.5 wt.%)].

In Comparative Example 14, etching was performed using an etching solution containing about 2 times as much sulfate as the etching solution of Example 1. As in Comparative Example 14, when the etching solution contained an excess of 10 wt% or more of sulfate, the Cu film etching rate was significantly decreased. As a result, a problem occurs that residues are generated in the Cu film portion.

Regarding Comparative Example 14, FIG. 4P of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 14, and FIG. 5B is a SEM photograph taken at high magnification to enlarge the residue region of FIG. 4P. to be. 6 is an energy dispersive spectroscopy (EDS) result for component analysis of the residue shown in FIG. 5B. Table 1 below shows the components and contents of the residue obtained from the EDS. From the results in Table 1, the residue of the Cu film generated when etching was performed using the etchant according to Comparative Example 14 was confirmed:

Element weight% at% OK 77.57 93.21 CuK 22.43 6.79

Comparative example  15

The compound included in the etchant of Comparative Example 15 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + HEDP (0.5 wt.%) + H ₂ O (12 wt.%)].

In Comparative Example 15, the etching was performed by adding 0.5 wt% of HEDP (1-Hydroxyethylidene diphosphonic acid, C ₂ H ₈ O ₇ P ₂ ) as an additive to the etchant of Example 1. The HEDP is a representative Cu corrosion inhibitor, and is a material generally used to obtain a smooth taper angle by controlling the etching rate of the Cu film. However, when the HEDP is added to the etchant according to the present application, it was confirmed that the etching rate of the Cu film is not preferable due to the decrease in the etching rate of Cu film and the occurrence of Cu residue.

Regarding Comparative Example 14, FIG. 4Q of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 14.

Comparative example  16

The compound included in the etchant of Comparative Example 16 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 weight%) + NaF (2 weight%) + (NH ₄ ) ₂ SO ₃ (5 weight%) + HEDP (1 weight%) + H ₂ O (11.5 weight%)].

In Comparative Example 16, the etching was performed by adding 1 wt% of HEDP (1-Hydroxyethylidene diphosphonic acid, C ₂ H ₈ O ₇ P ₂ ) as an additive to the etchant of Example 1. The HEDP is a representative Cu corrosion inhibitor, and is a material generally used to obtain a smooth taper angle by controlling the etching rate of the Cu film. However, when the HEDP is added to the etchant according to the present application, it was confirmed that the etching rate of the Cu film is not preferable due to the lowering of the etching rate, and thus the occurrence of Cu residue, which is comparative example 15 and comparative example 16 having different contents of the HEDP. Was a common result.

Regarding Comparative Example 16, FIG. 4R of the present application is an SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 16. FIG.

Comparative example  17

The compound included in the etchant of Comparative Example 17 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + CH ₃ N ₅ (0.2 wt.%) + H ₂ O (12.3 wt.%)].

In Comparative Example 17, etching was performed by adding 0.2 wt% of aminotetrazole (ATZ, CH ₃ N ₅ ) as an additive to the etching solution of Example 1. The ATZ is a representative Cu corrosion inhibitor, and is a material generally used to obtain a smooth taper angle by controlling the etching rate of the Cu film. However, it was confirmed that the addition of ATZ to the etching solution according to the present application is not preferable due to the lowering of the etching rate of the Cu film and the occurrence of Cu residue, as in the case of adding the HEDP.

Regarding Comparative Example 17, FIG. 4S of the present application is an SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 17.

Comparative example  18

The compound included in the etchant of Comparative Example 18 and the composition ratio of each were as follows: [H ₃ PO ₄ (63 wt%) + HNO ₃ (2 wt%) + CH ₃ COOH (14.5 wt%) + NH ₄ HF ₂ (1 wt.%) + NaF (2 wt.%) + (NH ₄ ) ₂ SO ₃ (5 wt.%) + CH ₃ N ₅ (0.5 wt.%) + H ₂ O (12 wt.%)].

In Comparative Example 18, 0.5 wt% of an additive, aminotetrazole (ATZ, CH ₃ N ₅ ), was added to the etchant of Example 1 to perform etching. The ATZ is a representative Cu corrosion inhibitor, and is a material generally used to obtain a smooth taper angle by controlling the etching rate of the Cu film. However, when the ATZ is added to the etchant according to the present application, as in the case of adding the HEDP, it was confirmed that the etching rate of the Cu film is not preferable due to the lowering of the etching rate and the resulting Cu residue, which is different from the content of the ATZ. It was a common result of Comparative Example 17 and Comparative Example 18.

Regarding Comparative Example 18, FIG. 4T of the present application is a SEM photograph of a Cu / Ti double layer etched using the etchant according to Comparative Example 18.

After etching the specimens using the etching solutions of Examples 1 and 2 and Comparative Examples 1 to 18, respectively, the results of the respective etching characteristics are summarized in Table 2 below:

EPD
(sec) Etch rate
(Å / sec) CD skew
(μm) Step length
(μm) Taper angle (°) problem Example 1 60 88 0.3 0.1 50 - Example 2 110 50 0.4 0.15 55 - Comparative Example 1 - - - - - Cu lack of etching Comparative Example 2 30 177 2.69 1.75 - Cu overetch Comparative Example 3 - - - - - Cu lack of etching Comparative Example 4 30 177 2.4 1.16 - Cu overetch Comparative Example 5 35 151 0.7 0.12 - Cu residue Comparative Example 6 70 75 3.05 1.03 - Pattern unevenness Comparative Example 7 65 81 1.05 0.4 - Loss increase Comparative Example 8 90 55 0.25 0.47 - Cu residue Comparative Example 9 80 66 0.23 0.32 - Cu residue Comparative Example 10 33 160 0.33 0.44 - Pattern loss Comparative Example 11 33 160 0.03 0.47 - Generate step width Comparative Example 12 35 115 0.35 0.79 - Generate step width Comparative Example 13 70 75 0.24 0.1 - Ti residue Comparative Example 14 90 55 0.64 1.13 - Cu residue Comparative Example 15 60 88 0.03 0.31 - Cu residue Comparative Example 16 60 88 0.35 0.25 - Cu residue Comparative Example 17 50 106 0.4 0.7 - Cu residue Comparative Example 18 65 81 1.8 0.7 - Cu residue

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (23)

As an etchant composition,
For the total weight of the etchant composition,
35% to 70% by weight phosphoric acid;
0.5 wt% to 8 wt% nitric acid;
Acetic acid 2% to 20%;
0.5 wt% to 10 wt% of a fluorine-containing compound; And
Containing residual amount of water,
Etchant composition.
The method of claim 1,
For the total weight of the etchant composition,
50% to 65% by weight phosphoric acid;
1% to 3% by weight nitric acid;
12 to 16 weight percent acetic acid;
1% to 4% by weight of a fluorine-containing compound; And
Containing residual amount of water,
Etchant composition.
The method of claim 1,
Wherein the fluorine-containing compound comprises at least one of HF, NaF, NaF ₂ , NH ₄ F, NH ₄ HF ₂ , H ₂ SiF ₆ , Na ₂ SiF ₆ , and KHF ₂ .
The method of claim 1,
Wherein the etchant composition can comprise two or more different types of the fluorine-containing compound.
The method of claim 1,
1 wt% to 10 wt% of the sulfate compound based on the total weight of the etchant composition, etchant composition.
The method of claim 1,
3 wt% to 7 wt% of the sulfate compound based on the total weight of the etchant composition, etchant composition.
The method according to claim 5 or 6,
The sulfate compound comprises at least one of an ammonium salt of sulfuric acid, an alkali metal salt of sulfuric acid, and an alkaline earth metal salt of sulfuric acid.
The method of claim 1,
The etchant composition is used to etch a multi-metal film, etchant composition.
The method of claim 8,
Wherein the multi-metal film comprises at least one layer of Cu or Cu-alloy, and at least one layer of Ti or Ti-alloy.
The method of claim 9,
The thickness ratio of the at least one layer of the Cu or Cu-alloy, and the at least one layer of the Ti or Ti-alloy comprises 5: 1 to 300: 1, the etchant composition.
The method of claim 1,
Wherein the temperature of the etchant composition is between about < RTI ID = 0.0 > 35 C < / RTI >
Forming a photoresist film having a predetermined pattern on a multi-metal film deposited on a substrate;
Forming a metal wiring pattern by using the photoresist film as a mask and etching the multi-metal film using an etchant composition; And
Removing the photoresist film:
Including;
The etchant composition, relative to its total weight,
35% to 70% by weight phosphoric acid;
0.5 wt% to 8 wt% nitric acid;
Acetic acid 2% to 20%;
0.5 wt% to 10 wt% of a fluorine-containing compound; And
Lt; RTI ID = 0.0 > water,
A method of etching a multi-metal film.
13. The method of claim 12,
The etchant composition, relative to its total weight,
50% to 65% by weight phosphoric acid;
1% to 3% by weight nitric acid;
12 to 16 weight percent acetic acid;
1% to 4% by weight of a fluorine-containing compound; And
Lt; RTI ID = 0.0 > water,
A method of etching a multi-metal film.
13. The method of claim 12,
Wherein the fluorine-containing compound comprises at least one of HF, NaF, NaF ₂ , NH ₄ F, NH ₄ HF ₂ , H ₂ SiF ₆ , Na ₂ SiF ₆ , and KHF ₂ .
13. The method of claim 12,
Wherein the etchant composition may comprise two or more different classes of the fluorine-containing compounds.
13. The method of claim 12,
The etchant composition comprises a 1% to 10% by weight of the sulfate compound relative to the total weight thereof, multi-metal film etching method.
13. The method of claim 12,
The etchant composition comprises a 3% to 7% by weight of the sulfate compound relative to the total weight thereof, multi-metal film etching method.
The method according to claim 16 or 17,
The sulfate compound is a multi-metal film etching method comprising at least one of ammonium salt of sulfuric acid, alkali metal salt of sulfuric acid, and alkaline earth metal salt of sulfuric acid.
13. The method of claim 12,
Wherein said multimetal film comprises at least one layer of Cu or Cu-alloy, and at least one layer of Ti or Ti-alloy.
The method of claim 19,
The thickness ratio of the at least one layer of Cu or Cu-alloy, and the at least one layer of Ti or Ti-alloy comprises 5: 1 to 300: 1.
21. The method of claim 20,
Wherein at least one layer of the Cu or Cu-alloy comprises a gate electrode or a source / drain electrode.
13. The method of claim 12,
Wherein etching the multi-metal film comprises performing at a temperature between 35 [deg.] C and 70 [deg.] C.
13. The method of claim 12,
Wherein the etchant composition comprises spraying for 30 seconds to 300 seconds.

Images