KR20130045190A - Etching solution composition for metalfilm comprising copper layer and/or copper alloy layer, and etching method using same - Google Patents

Abstract

PURPOSE: An etchant composition for a metal layer including a copper layer and/or a copper alloy layer and an etching method thereof are provided to etch a metal film and a laminated film to a high precision. CONSTITUTION: An etchant composition for a metal layer including a copper layer and/or a copper alloy layer and an etching method thereof includes cu(II) ion, β-alanine, and water. [Reference numerals] (AA) Cu/CuMn substrate J.E.T.(s); (BB) Copper ion concentration(mol/l)

Description

Etching liquid composition for metal film containing copper layer and / or copper alloy layer and etching method using same {ETCHING SOLUTION COMPOSITION FOR METALFILM COMPRISING COPPER LAYER AND / OR COPPER ALLOY LAYER, AND ETCHING METHOD USING SAME}

The present invention relates to an etching composition for etching a metal film, in particular a copper layer and / or a copper alloy layer / molybdenum laminated film, comprising a copper layer and / or a copper alloy layer. In particular, the present invention can be used to form microstructures such as wirings, circuits, electrodes, and connecting portions, and typically relates to an etching liquid composition for a metal laminate film used for manufacturing a gate, a source, and a drain electrode of a liquid crystal display. will be.

Conventionally, aluminum and aluminum alloys, which are inexpensive and have low electrical resistance, are used for gate, source, and drain electrode materials of liquid crystal displays, but since they have relatively low adhesion to glass substrates that are practically inferior, molybdenum, etc. Has been used as an aluminum / dissimilar metal laminated film using a film of a metal or an alloy thereof.

On the other hand, in recent years, large screens and high definition of liquid crystal displays have progressed, and switching to lower resistance copper wiring has been required. Since the adhesion to the glass substrate, which is also copper, is low, it is used as a lamination film of copper / copper alloy and copper / molybdenum by using a copper alloy, molybdenum or the like under the copper to form a gate, source and drain electrode material. Application review is being actively conducted.

In recent years, attempts have been made to switch switching elements from amorphous silicon TFTs (thin film transistors) to oxide semiconductor TFTs to cope with high-speed response and low power consumption in order to cope with 3D display. For this reason, a structure is proposed in which a ZnO (zinc oxide) film or an IGZO (indium gallium-zinc-oxide) film is formed under the gate, source and drain electrodes.

When etching such an oxide semiconductor film, a neutral to weakly basic etching solution composition has been proposed (Patent Document 1). Moreover, it is known that an oxide semiconductor film melt | dissolves also in strong basicity (patent document 2, nonpatent literature 1). For example, in a lamination structure of a copper / copper alloy / oxide semiconductor film or a copper / molybdenum / oxide semiconductor film, in order to dissolve only the copper / copper alloy or copper / molybdenum film without eroding the oxide semiconductor film, a neutral to basic An etching liquid composition is needed.

As a basic copper etching liquid composition, hydrogen peroxide type | system | group, copper (II) ion + ammonia type, etc. are known (patent document 3, 4). However, hydrogen peroxide is impractical because, in basicity, the stability is lowered and the liquid life is shortened. In addition to the high etching rate of copper and the lack of micromachinability, the copper (II) ion + ammonia system has a pKa of 9.25, so that the ammonia volatility is high at pH 9 and above, so it is difficult to maintain the etching performance constantly.

As described above, in the neutral to basic region, the etching liquid of the film made of copper / copper alloy or the laminated film of the metal and other layers such as molybdenum can be etched with high processing accuracy, and the batch etching liquid having excellent liquid stability. The composition is not developed.

As a copper etching liquid composition which uses a copper (II) ion as an oxidizing agent, the copper chloride + hydrochloric acid type | system | group and the above-mentioned copper (II) ion + ammonia type are known. However, all have a very high etching rate of copper and do not have micromachinability. In addition, the copper chloride + hydrochloric acid system can be used only in strong acids.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-210630 Patent Document 2: Japanese Patent Application Laid-Open No. 2008-141113 Patent Document 3: Japanese Patent Application Laid-Open No. 2009-091656 Patent Document 4: Japanese Patent Application Laid-Open No. 2005-105333

[Non-Patent Document 1] Utsumi Kentaro et al., "Characteristics of ZAO (Al-Added ZnO) Thin Films," Tosoh Research and Technology Report, Vol. 49, 2005, pp. 45-48

That is, the subject of this invention solves the said problem, and can etch the laminated | multilayer film of the metal film which has a copper layer and / or a copper alloy layer, or the layer and the layer which consists of another metal with high precision, It is to provide a long etchant composition.

Based on the above problems, the present inventors have found that the copper / copper alloy or copper / molybdenum laminated film can be etched in the weakly basic region by using copper (II) ions as the oxidizing agent and combining β-alanine as the complexing agent. As a result of further discovery and further research, the present invention has been completed.

That is, this invention relates to the following etching liquid compositions and etching methods.

[1] An etching liquid composition for etching a metal film containing a copper layer and / or a copper alloy layer, wherein the etching liquid composition contains copper (II) ions, β-alanine and water.

[2] The etching solution composition according to [1], wherein pH is 8.5 to 11.

[3] The etching liquid composition according to [1] or [2], wherein the volume molar concentration of copper (II) ions is 0.01 to 0.6 mol / l.

[4] The etching liquid composition according to any one of [1] to [3], wherein a volume molar concentration of β-alanine is 0.5 to 3.0 mol / l.

[5] The etching liquid composition according to any one of [1] to [4], which contains iodic acid.

[6] [1] to [with a pH of 8.5 to 11, containing 0.01 to 0.6 mol / l of copper (II) ion, 0.5 to 3.0 mol / l of β-alanine, 0.01 to 1.0 mol / l of iodic acid, and water; The etching liquid composition in any one of 5].

[7] The etching solution composition according to any one of [1] to [6], which does not contain one or two or more compounds selected from the group consisting of ethylenediamine, ethylenediamine tetraacetic acid, glycine, and L-alanine.

[8] An etching method comprising etching a metal film containing a copper layer and / or a copper alloy layer using the etching solution composition according to any one of [1] to [7].

[9] The etching method according to [8], wherein the metal film is a single layer film of a copper layer or a copper alloy layer, or a laminated film containing at least one copper layer or a copper alloy layer.

[10] The etching method according to [9], wherein the metal film is a laminated film further comprising a layer made of a material which can be oxidized by copper (II) ions.

[11] The etching method according to [10], wherein the material which can be oxidized by copper (II) ions is molybdenum.

[12] The etching method according to any one of [8] to [11], wherein the metal film is formed on a glass substrate, on a Si wafer, or on an oxide semiconductor.

The etching liquid composition of this invention can dissolve a metal layer (for example, molybdenum layer) etc. which can be oxidized by a copper layer, a copper alloy layer, copper (II) ion in basicity. In addition, it can be used under neutral to basic pH conditions that do not corrode the oxide semiconductor film or the like. For example, even when the respective layers are formed on the oxide semiconductor, the liquid crystal display is not damaged without damaging the exposed oxide semiconductor film. Formation of fine structures such as electrode formation for dragons can be effectively performed.

In addition, copper (II) ions become an oxidizing agent and are safe without foaming, explosiveness, and the like. Since liquid recovers naturally with dissolved oxygen even when the oxidizing agent is consumed, the liquid life is long and the storage stability is excellent. In addition, since β-alanine, which acts as a complexing agent, can also act as a pH buffer, it is possible to prevent changes in etching characteristics due to pH variation.

1 is a graph showing the change in the iodic acid content change in the etching solution composition.
2 is a graph showing the etching behavior at the time of changing the pH in the etching liquid composition.
3 is a graph showing the concentration of copper ions, β-alanine in the etching solution composition and the just etching time of the copper alloy substrate.
It is a graph which shows the copper ion, (beta) -alanine concentration, and copper plate etching rate of an etching liquid composition.

The etching liquid composition of this invention contains the metal film (The "metal film which consists of a copper layer and / or a copper alloy layer") containing a copper layer and / or a copper alloy layer, especially a copper layer and / or a copper alloy layer / It is for etching a molybdenum laminated film, and contains copper (II) ion, (beta) -alanine, and water. By using a copper (II) ion + β-alanine-based etching liquid composition, since there is no volatile matter other than water, the liquid stability is high, and an etching ratio suitable for the mass production process, for example, a copper / copper alloy film, a copper / molybdenum film, or the like Can be etched.

The etching liquid composition of this invention can be used within the range of weakly basic to basic, and can etch a metal film containing a copper layer etc. without eroding an oxide semiconductor film.

PH of the etching liquid composition of this invention becomes like this. Preferably it is 8.5-11, Especially preferably, it is 9.0-10.5, More preferably, it is 10-10.5. If the pH is lower than 8.5, the etching rate of copper and molybdenum decreases, so that the substrate processing time is extended. If the pH is higher than 11, the etching rate of copper decreases, and precipitation of copper hydroxide may occur.

The pH adjuster which can be used for the etching liquid composition of this invention is not specifically limited, Tetramethylammonium hydroxide (TMAH), lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, and some amine compounds can be used. Tetramethylammonium hydroxide (TMAH) is preferred in view of exhibiting no interaction with copper ions and low volatility.

In the etching solution composition of the present invention, since the copper (I) ion after the copper (II) ion acts as an oxidant is easily returned to the copper (II) ion as dissolved oxygen in the liquid, it is used for a long time without replenishing components other than water. It is possible and long life. Thus, by using a copper (II) ion + (beta) -alanine system, it has the outstanding performance conventionally existing, such as long-term storage stability.

Looking at the functional group of the etching solution composition of the present invention as follows.

In the etching liquid composition of this invention, a copper layer, a copper alloy layer, a molybdenum layer, etc. are oxidized with copper (II) ion. In basic, copper (II) ions precipitate as copper hydroxide, but stably exist in solution as copper (II) -β-alanine complex ([Cu (H ₂ NCH ₂ CH ₂ COO) ₂ ]) by adding β-alanine. Can be. Copper (II) -β-alanine complexes are not hydrolyzed as a whole, but are easily soluble in water because they have the same intramolecular polarity as copper-glycine complexes.

The metal copper in the metal film to be etched is oxidized by copper (II) ions and dissolved as copper (I) ions. The copper (II) ion which oxidized the metal copper is reduced, and also becomes copper (I) ion. These copper (I) ions do not act as oxidizing agents, but are easily oxidized by dissolved oxygen and return to copper (II) ions. In this way, the function as an oxidant is restored. The redox reaction of such copper is shown in (Formula 1) and (Formula 2). In addition, since copper ions are actually present as β-alanine complexes, the reaction formulas are (Formula 3) and (Formula 4). Further, "βAla" in the formula is H ₂ NCH ₂ CH ₂ COO ^- represents a.

[Formula 1]

Cu + Cu ^{2 +} → 2Cu ⁺ (Equation 1)

2Cu ⁺ + 1 / 2O ₂ + 2H ⁺ → 2Cu ^{2 +} + H ₂ O (Equation 2)

Cu + [Cu (βAla) ₂ ] + 2βAla → 2 [Cu (βAla) ₂ ] ^- (Equation 3)

2 [Cu (βAla) ₂ ] ^- + 1 / 2O ₂ + 2H ⁺ → 2 [Cu (βAla) ₂ ] + H ₂ O (Equation 4)

The etching liquid composition of this invention can also etch the layer which consists of molybdenum, for example. That is, molybdenum is also oxidized and dissolved by copper ions, but β-alanine complexes are not formed, and molybdenum is stably present in the liquid as molybdate ions. The redox reactions become (Formula 5) and (Formula 6), but even in this case, since the copper ions are actually present as β-alanine complexes, the reaction formulas are (Formula 7) and (Formula 8).

[Formula 2]

_{^{Mo + 6Cu 2 + + 4H 2}} O → MoO 4 2 - + 6Cu + + 8H + ( Equation 5)

6Cu ⁺ + 3 / 2O ₂ + 6H ⁺ → 6Cu ^{2 +} + 3H ₂ O (Equation 6)

Mo + 6 [Cu (βAla) 2] + 4H 2 O → MoO 4 2 - +6 [Cu (βAla) 2] - + 8H + ( (7))

6 [Cu (βAla) ₂ ] ^- + 3 / 2O ₂ + 6H ⁺ → 6 [Cu (βAla) ₂ ] + 3H ₂ O (Equation 8)

Chelate compounds, such as ethylenediamine and ethylenediamine tetraacetic acid, and amino acids, such as glycine and L-alanine, form complexes easily with copper (II) ion. However, even if these compounds are used as a complexing agent of the etching liquid composition which made copper (II) ion the oxidizing agent, etching does not advance most. The reason for this is that first, these compounds form a very stable complex with copper (II) ions, and the copper (II) ions do not act as an oxidizing agent. Second, these compounds are different from copper (I) ions. Since the complex cannot be formed, it can be considered that the reaction is completed only by forming an oxide film on the copper surface. On the other hand, when ethylenediamine, ethylenediamine tetraacetic acid, glycine, and L-alanine are used as the complexing agent, the etching rate of molybdenum also significantly decreases. In the etching solution composition of the present invention, since molybdenum dissolves without forming a complex with β-alanine, it will not be influenced by the complexing agent. For this reason, in the complexing agents other than (beta) -alanine, the first reason that the stability of a copper complex is too high and copper (II) ion becomes difficult to act as an oxidizing agent is considered to be the main reason that an etching does not advance.

The complex stability constants of copper (II) -β-alanine complexes are relatively low compared to ethylenediamine, ethylenediamine tetraacetic acid, glycine, L-alanine, etc., so that only a short time is observed by appropriately repeating coordination and dissociation. It is thought that the copper (II) ion of glass to act as an oxidizing agent. Naturally, from the viewpoint of chemical equilibrium, dissociation also occurs in a complex composed of an exemplified compound such as ethylenediamine and copper (II) ions, but the amount is very small (or the dissociation time is very short) and is insufficient to act as an oxidizing agent. . Thus, β-alanine has an appropriate complex stability constant and the property of forming a complex with both copper (I) ions and copper (II) ions. Thus, β-alanine is used in an etching solution composition containing copper (II) ions as an oxidizing agent. It is very excellent as a complexing agent to be used.

Examples of the compound exhibiting the same properties include chloride ions in the acidic region and imidazole in the neutral region. However, the former can be used only in the acidic region, and both have a disadvantage in that molybdenum can hardly be dissolved.

Considering the dissolution and reoxidation reaction of copper using the above formulas (1) and (2), in order to dissolve 1 mol of copper, 1 mol of copper (II) ions is required, and 2 mol of copper (I) ions generated. It can be seen that 2 moles of hydrogen ions are consumed to reoxidize. That is, pH of an etching liquid composition rises by a series of redox reactions.

Similarly, when the molybdenum is dissolved using (Formula 5) and (Formula 6), 6 mol of copper (II) ions are consumed to dissolve 1 mol of molybdenum, and 8 mol of hydrogen ions are generated. 6 mol of hydrogen ions are consumed for oxidation of 6 mol of copper (I) ions produced. In the dissolution reaction of 1 mol of molybdenum and the oxidation reaction of copper (I) ions following this, 2 mol of hydrogen ions are generated to reduce the pH of the etching solution composition.

2 mol of hydrogen ions are consumed for dissolving 1 mol of copper and recovery of copper (II) ions, and 2 mol of hydrogen ions are produced for dissolving 1 mol of molybdenum and recovery of copper (II) ions. When copper and molybdenum are dissolved in the same mole, the pH of the etching liquid composition does not change, but considering the metal film thickness, specific gravity, atomic weight, etc. of the copper / molybdenum laminated film, the molybdenum dissolved amount is 1/20 to 1 / 5 or so. For this reason, the pH of an etching liquid composition actually raises.

In the etching solution composition of the present invention, the volume molar concentration of copper (II) ions is preferably 0.01 to 0.6 mol / l, particularly preferably 0.05 to 0.3 mol in view of the relationship with the volume molar concentration of β-alanine. / l. If the volume molar concentration of the copper (II) ion is too high, it tends to cause a decrease in the etching rate or pH fluctuation due to lack of β-alanine in the glass, and if the volume molar concentration of the copper (II) ion is too low, There exists a tendency which leads to the fall of the etching rate by lack.

In the etching liquid composition of this invention, copper (II) ion functions as an oxidizing agent. The copper ion source is not particularly limited as long as it dissolves in water, and examples thereof include copper sulfate, copper nitrate, copper acetate, copper chloride, and copper pyrophosphate. It is preferable to use copper sulfate, copper nitrate, copper acetate, etc. from a viewpoint of etching performance, solubility in water, etc.

β- alanine indicates the dissociation equilibrium shown in equation (9), the number of acid dissociation constant in water is a _{pKa 1 = 3.55, pKa 2 =} 10.24.

(3)

(식 9)

(Equation 9)

In the etching liquid composition of this invention, although the etching ratio of copper rises especially in pH10 or more, the dissociation state of (beta) -alanine has a big influence on this. That is, in order to form a complex with copper ions, β-alanine needs to be in the form of H ₂ NCH ₂ CH ₂ COO ⁻ shown on the right side of (Formula 9). Also, since pKa ₂ is 10.24, β-alanine exhibits a strong buffering action in the vicinity of pH10. By making β-alanine 5 to 20 times the copper concentration in a molar ratio, the etching rate of copper is increased, and the excess amount of β-alanine exhibits a sufficient effect as a pH buffer. After all, even if the redox of copper becomes a factor which raises pH, using a beta-alanine as a complexing agent can suppress pH fluctuations.

In the etching liquid composition of this invention, when the volume molar concentration of (beta) -alanine is 5 to 20 times the range of the volume molar concentration of copper (II) ion, favorable etching performance can be obtained, Preferably it is 0.5-3.0 mol / l, More preferably, it is 1.0-2.5 mol / l. β-alanine can act as a complexing agent and form a complex with copper (II) ions so that copper (II) ions can be stably present in the liquid even under basic conditions. In addition, when the copper surface is oxidized to copper (II) ions, complexes are rapidly formed with the copper (I) ions and diffused into the liquid, thereby suppressing the formation of oxide films on the copper surface and precipitation in the liquid, thereby continuing the continuous etching. Is making it possible. In addition, since β-alanine has a maximum buffering action in the vicinity of pH 10, β-alanine also has a function as a buffer for suppressing the pH variation of the etching solution composition. When there is too little (beta) -alanine, the etching rate of copper will fall and pH fluctuation will increase, and when too much, the viscosity of etching liquid composition will rise and etching performance will fall.

The etching liquid composition of this invention may contain etching accelerators, such as iodic acid, for example. In general, iodic acid is an oxidizing agent, and copper can be etched under acidic conditions, but there is a problem that iodine or copper iodide, which is a reduction product, precipitates on the substrate. However, since it does not act as an oxidizing agent under basic conditions, etching of copper hardly progresses by itself. However, in the presence of basic copper (II) -β-alanine and a complex, the etching rate of copper can be raised significantly. Iodic acid is effective by the addition of a small amount, and even if a large amount of copper is dissolved, the component content does not change. In addition, if a certain amount of iodic acid is added, even if it increases more, the etching rate of copper will not change. Therefore, it is thought that iodic acid acts as a catalyst which accelerates copper etching in basic coexistence of a copper (II)-(beta) -alanine complex. Iodic acid is not only effective in addition to a large amount, but since it is an acidic substance itself, a large amount of pH adjusting agent for making the etching liquid composition basic is required. For this reason, as a compounding quantity of iodic acid, Preferably it is 0.01-1.0 mol / l, More preferably, it is 0.03-0.5 mol / l.

The etching liquid composition of this invention, Preferably, 0.01-0.6 mol / l of copper (II) ions, 0.5-3.0 mol / l of beta-alanine, 0.01-1.0 mol / l of iodic acid, and water, pH is 8.5- 11 Moreover, Especially preferably, it contains 0.05-0.3 mol / l of copper (II) ions, 1.0-2.5 mol / l of (beta) -alanine, 0.03-0.5 mol / l of iodic acid, and water, and pH is 9.0-10.5.

Moreover, the etching liquid composition of this invention consists only of the copper salt, (beta) -alanine, a pH adjuster, and water which become a copper (II) ion source substantially in one form. Moreover, in another form, it consists only of the copper salt, (beta) -alanine, iodic acid, a pH adjuster, and water which become a copper (II) ion source substantially.

The etching liquid composition of this invention, Preferably, it does not contain the component which forms a complex with copper (II) ion more easily than (beta) -alanine. As such a component, ethylenediamine, ethylenediamine tetraacetic acid, glycine, L-alanine, etc. are mentioned, for example. In the case where the component is included, etching of the copper layer, copper alloy layer, molybdenum layer, etc. hardly proceeds or the etching rate may be greatly reduced depending on the content of the component and the pH of the etching solution composition. .

Using the etching liquid composition of this invention, the metal film containing a copper layer and / or a copper alloy layer, especially a copper layer and / or a copper alloy layer / molybdenum laminated film can be etched.

The metal film which can be etched by the etching method of the present invention is typically a single layer film of a copper layer or a copper alloy layer, or a laminated film including at least one copper layer or a copper alloy layer. Here, a copper alloy layer is a metal layer which consists of copper and arbitrary metals, and contains copper as a main component. For example, a CuMn layer, CuMgAl layer, CuMgAlO layer, CuCaO layer, etc. are mentioned. The copper alloy layer typically contains at least 90 weight percent copper and preferably at least 95 weight percent copper.

The metal film to be subjected to the etching method of the present invention may be a laminated film further including a layer made of a material which can be oxidized by copper (II) ions. The material which can be oxidized by copper (II) ions is a material which is oxidized by copper (II) ions among metals, metal oxides, etc., and becomes an ion and melt | dissolves in etching liquid, For example, molybdenum and molybdenum as a main component Alloys and oxides thereof. In addition, the etching liquid composition of the present invention is excluded from the material which can be oxidized by the above copper (II) ions because it is not suitable for etching titanium or titanium / molybdenum alloy because of its properties.

The film etched by the etching method of the present invention may be formed on an oxide semiconductor such as on a glass substrate, on a Si wafer, or on ZnO or IGZO.

About the etching method of this invention, 30-50 degree is preferable about the temperature which etches. At low temperatures, the etching rate may be low, and the etching time may be too long. At high temperatures, the etching rate may be high and the controllability of the etching may decrease.

(Example)

The present invention will be described in detail with reference to the following Examples, but the present invention is not limited to these Examples.

On the other hand, in each of the following examples, unless otherwise specified, the etching liquid composition shown as a composition example raised pH to predetermined value using 22% tetramethylammonium hydroxide. However, when a large amount of tetramethylammonium hydroxide was needed for pH adjustment, and it exceeds a predetermined liquid amount (for example, 100 ml) before reaching target pH, 30% sodium hydroxide aqueous solution was used. In addition, 10% sulfuric acid was used when reducing pH.

The etching rate (ER) of copper and molybdenum was immersed in 100 ml of the etching liquid composition showing each rolled metal plate (2 cm x 2 cm x 0.1 mm) as a composition example for 2 minutes under conditions of a liquid temperature of 35 DEG C and a stirring speed of 500 r.pm, and etching It calculated from the weight change before and after.

Further, after forming a copper alloy film or molybdenum film (200 to 500 kPa) on the glass substrate by sputtering, a copper film (3000 kPa) is formed again by sputtering, and a copper layer on the upper side and a copper alloy layer or molybdenum layer on the lower side. This laminated substrate was prepared. Subsequently, patterning was performed on the copper layer film using a resist to complete a copper / copper alloy or copper / molybdenum laminated film substrate.

The copper / copper alloy or copper / molybdenum laminated film substrate was etched to 100 ml of the etching solution composition shown in the composition example under conditions of a liquid temperature of 35 ° C. and a stirring speed of 700 r · p · m. Since the etching liquid composition shown in a composition example was almost blue-blue purple, the beaker was placed in the acrylic water tank, and the just etching time (J.E.T.) was determined by the light which permeate | transmits light from the back side. After immersing a board | substrate in 1.5 times of just etching time for each etching liquid composition, water washing and drying were performed and SEM observation was performed.

(Example 1)

The effectiveness of each complexing agent was compared in the composition which made copper sulfate 0.079 mol / l (5000 ppm as copper (II) ion), and a complexing agent 0.5-1 mol / l (the addition amount changes with the required amount of solubility and pH adjustment). Each composition example used is shown in Table 1, and a result is shown in Table 2.

On the other hand, copper sulfate did not melt | dissolve under basic conditions without a complexing agent.

Example CuSO ₄
(mol / l) Complexing agent (mol / l) pH compound Addition amount One
2
3
4
5
6
7
8
9
10 0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079 beta-alanine
Glycine
4-aminolactic acid
L-alanine
Ethylenediamine
Citric acid
L (+)-Tartrate
Imino diacetic acid
Nitric acid trinitrate
Ethylenediamine Tetraacetic Acid 1.0
1.0
1.0
1.0
0.5
0.5
1.0
1.0
1.0
0.5 10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0

Example Cu / Mo Substrate Treatment Time (s) Metal Plate E.R. (nm / min.) Cu film disappeared Mo film disappeared Cu Mo One
2
3
4
5
6
7
8
9
10 160
400
×
270
×
×
×
×
×
× 235
×

× 127
33
17
34
16
4
One
6
4
8 13
2
11
4
One
4
0
5
2
2

 X: It shows that a copper film or an underlying molybdenum film does not melt | dissolve even if it immerses for 10 minutes.

In the β-alanine, glycine, and L-alanine addition system, the 3000 kPa copper layer could be dissolved within 7 minutes, but only the β-alanine addition system (composition 1) was able to dissolve to 200 molybdenum layers within 10 minutes. Moreover, only when copper and molybdenum were high in the case where a complexing agent was (beta) -alanine, it was confirmed also by the etching rate of a metal plate.

(Example 2)

Based on the composition example 1, the etching behavior at the time of adding iodic acid in various concentration was compared. Each composition example used is shown in Table 3, and a result is shown in Table 4 and FIG.

Example Component Content (mol / l) pH CuSO ₄ βAla HIO ₃ One
11
12
13
14
15
16
17
18
19
20 0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
0.079
-
- 1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0 -
0.01
0.03
0.05
0.10
0.15
0.30
0.50
1.00
-
0.1 10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0
10.0

Example Cu / CuMn Substrate
JET (s) Cu / Mo substrate
JET (s) Metal Plate E.R. (nm / min.) Cu Mo One
11
12
13
14
15
16
17
18
19
20 250
130
85
84
80
76
78
79
90
×
× 235
-
-
-
110
-
110
110
120
×
× 127
281
337
339
337
349
343
329
263
16
23 13
-
-
-
13
-
12
13
10
3
6

X: It shows that etching is not complete even if it immerses for 10 minutes.

By adding 0.01 mol / l of iodic acid, the etching rate of copper rose more than twice, and nearly tripled when adding 0.03 mol / l. Moreover, there was no big change in the etching rate of molybdenum regardless of the presence or absence of iodine acid. The treatment time of the copper / copper alloy substrate and the copper / molybdenum substrate also showed the same behavior.

In the copper sulfate-free system (composition examples 19 and 20), although the etching rate of copper and molybdenum increased slightly with or without iodine acid, the change was extremely small, and when iodic acid did not act as an oxidant in basicity and coexisted with copper ions. It is thought that the etching rate of copper can be raised catalytically. It is very useful as an additive because it has a large effect in a small amount.

(Example 3)

Based on the composition example 14, the complexing agent different from (beta) -alanine was added together and the behavior was compared. Each composition example used is shown in Table 5, and a result is shown in Table 6.

Furtherance Component Content (mol / l) pH CuSO ₄ βAla HIO ₃ EDA EDTA 14
21
22 0.079
0.079
0.079 1.0
1.0
1.0 0.1
0.1
0.1 -
0.5
- -
-
0.5 10.0
10.0
10.0

Furtherance Color Cu / CuMn Substrate
JET (s) Cu / Mo substrate
JET (s) Metal Plate E.R. (nm / min.) Cu Mo 14
21
22 Blue purple
blue
Deep purple 80
△
△ 110
△
△ 337
21
8 13
2
One

△: 600 (s) or more

In the β-alanine alone system, etching proceeds for both copper and molybdenum. However, when ethylenediamine (EDA) and ethylenediamine tetraacetic acid (EDTA) are added thereto, the etching rate is very low.

This is because ethylenediamine or ethylenediamine tetraacetic acid complexes with most copper (II) ions, resulting in highly stable copper complexes, which prevented copper (II) ions from acting as oxidizing agents, and the complex stability constants of β-alanine were relatively In the β-alanine simple system, copper (II) ions and β-alanine can be appropriately coordinated and dissociated in the β-alanine alone to release free copper (II) ions as oxidants.

On the other hand, the liquid color of the three compositions in Table 6 is different because the copper complex as the main component is different.

In addition, when copper (II) ions oxidize the copper, both become copper (I) ions. If this copper (I) ion cannot be removed from the surface of the metal copper quickly, the copper surface is covered with copper oxide or copper hydroxide to stop the etching. β-alanine has the ability to form complexes of both copper (I) ions and copper (II) ions, which is very useful as a complexing agent for use in etching liquid compositions containing copper (II) ions as oxidants. On the other hand, molybdenum is considered to be dissolved as molybdate by oxidation with copper (II) ions and is not related to the complexing ability of β-alanine.

(Example 4)

Based on the composition example 14, the test which changed only pH of adding tetramethylammonium hydroxide addition amount was done. The results are shown in Table 7 and FIG. 2.

Furtherance pH Cu / CuMn Substrate
JET (s) Cu / Mo substrate
JET (s) Metal Plate E.R. (nm / min.) Cu Mo 23
24
25
26
27
14
28
29
30 7.0
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5 △
△
560
220
115
80
140
290
△ △
△
560
235
140
110
140
260
△ 13
23
43
104
220
337
393
234
37 One
3
4
6
10
13
18
24
31

△: 600 (s) or more

As shown in Table 7, the pH at which the substrate processing time is shortest is 10, and it can be seen that the copper / copper alloy substrate and the copper / molybdenum substrate can be treated in the range of pH 8.5 to 11. The etching rate of a copper plate showed the maximum value in pH10.5, and in molybdenum plate, the etching rate was high, so that pH was high. In the etching rate of the metal plate, it is expected that the substrate treatment time exhibits a minimum value at pH 10.5, but it is considered that the difference between the surface state and the film quality of the metal film produced from the rolled metal plate and the sputtering material is not so practical.

(Example 5)

Table 8, FIG. 3 and FIG. 4 show trends in etching changes when the copper (II) ions and β-alanine concentrations were changed.

Example Cu ^{2 +} concentration
(ppm) Component Content (mol / l) pH Cu / CuMn
JET (s) Cu plate ER
(nm / min) CuSO ₄ βAla HIO ₃ 31
32
33
34
35 635
1,500
2,500
5,000
7,500 0.010
0.024
0.039
0.079
0.118

0.5













0.1













10.0 126
122
228
△
△ 120
194
203
32
16 36
37
14
38
39 635
2,500
5,000
10,000
15,000 0.010
0.039
0.079
0.157
0.236

1.0 140
75
80
210
600 114
283
337
154
44 40
41
42
43
44 2,500
5,000
10,000
15,000
20,000 0.039
0.079
0.157
0.236
0.315

1.5 80
57
58
108
175 273
382
466
398
274 45
46
47
48
49
50 2,500
5,000
10,000
15,000
20,000
25,000 0.039
0.079
0.157
0.236
0.315
0.393

2.0 82
59
50
60
62
89 251
391
498
495
404
303 51
52
53
54 5,000
10,000
20,000
30,000 0.079
0.157
0.315
0.472
2.5 56
45
49
64 334
444
467
377 55
56
57
58
59 5,000
10,000
20,000
30,000
40,000 0.079
0.157
0.315
0.472
0.629

3.0 64
50
48
55
90 300
399
421
362
226

△: 600 (s) or more

As the concentration of copper (II) ions and β-alanine increases, the etching rate of the etched copper plate increases, the processing time of the copper substrate also shortens, and the region showing a stable etching trend is enlarged. Moreover, when the (beta) -alanine concentration existed about 5-20 times with respect to copper (II) ion concentration, favorable etching was possible.

(Example 6)

After melt | dissolving a large amount of copper powder, the etching test was done every fixed time. Table 9 shows the composition example used, and the results are shown in Table 10.

Example Component Content (mol / l) pH CuSO ₄ βAla HIO ₃ 60 0.079 1.5 0.05 10.0

Cu melt amount
(ppm) Elapsed time
(hr.) Cu / CuMn Substrate
JET (s) Cu plate ER
(nm / min) pH 0 0 62 380 10.00
2500 0.5
3
6
24 120
65
59
60 304
414
438
463 9.96
9.99
9.97
10.04
5000 One
3
6
24 340
64
59
60 257
422
463
437 9.95
9.97
9.99
10.06

As shown in Table 10, the change trend of self-recovery of the etching liquid composition was confirmed. In the composition example 60, the time required to melt | dissolve 2500 ppm of copper powders was 0.5 hour, and it was 1 hour at 5000 ppm. Immediately after copper dissolution, the etching rate of the copper plate was lowered, and the processing time of the copper / copper alloy substrate was also extended, but almost recovered after 3 hours and completely recovered after 6 hours.

In this system, the copper (II) ion which is an oxidizing agent and the metal copper which oxidized and melt | dissolved also melt | dissolve in liquid as copper (I) ion. Since the copper (I) ion does not act as an oxidant, the etching performance temporarily decreases, but the etching performance is restored because all of the copper (I) ion is reoxidized by dissolved oxygen and returns to the copper (II) ion. In the reoxidation reaction, hydrogen ions are consumed, but the buffering effect by β-alanine is high near pH 10, and it is possible to suppress the rise in pH to the minimum. This system was found to be capable of self-recovering by dissolved oxygen and suppressing pH fluctuations even when a large amount of copper was dissolved to reduce the oxidant.

(Example 7)

In Example 6, a large amount of copper powder was dissolved at a time, but the copper dissolution rate in the flat panel display mass production process is considered to be about 200 ppm per hour (10th generation, opening ratio 95%, throughput 25 sheets / hr, Cu / Cu alloy film thickness is assumed to be 320-350nm, liquid quantity 3000L). For this reason, 400 ppm of copper powder was added to the composition example 60, and the etching change trend until 2 hours passed was observed, and it confirmed that after 30 to 60 minutes, processing time might become equivalent to an initial state (Table 11). For this reason, if it melt | dissolves about 200 ppm per hour, continuous operation is possible without prolonging the substrate processing time.

Cu melt amount
(ppm) Elapsed time
(min.) Cu / CuMn Substrate
JET (s) Cu single layer substrate
JET (s) 0 - 60 49
400 10
30
60
90
120 70
60
58
61
58 56
54
51
47
47

(Example 8)

The copper monolayer substrate, the copper / copper alloy substrate, and the copper / molybdenum substrate were etched using the composition example 14, and the etching states were compared. The results are shown in Table 12.

Laminated structure Laminated film thickness
(nm) Processing time (s)
JET × 1.5 Cross section shape SE
(Μm) leftover Cu single layer
Cu / CuMn
Cu / Mo
Cu / CuMgAl
Cu / CuMgAlO
Cu / CuCaO 300
300/50
300/20
300/50
300/50
300/50 83
120
165
116
108
114 Near vertical taper
Near vertical taper
Perpendicular
Near vertical taper
Near vertical taper
Perpendicular 0.3
0.5
0.5
0.6
0.7
0.7 none
none
slightly
none
slightly
slightly

In all, the cross-sectional shape was vertical to nearly tapered, and the side etching amount was 1 µm or less. Although there are some laminated film substrates in which etching residue occurs slightly at the immersion time of 1.5 times the just etching time, the residue can be removed by prolonging the immersion time.

Since the present invention forms a microstructure of wirings, circuits, electrodes, and connecting portions by etching copper films and copper-based alloy films, copper / copper alloy laminated films, copper layers and / or copper alloy layers / molybdenum laminated films. In particular, it can be used as an etching liquid composition for metal laminated films used for preparing gate, source and drain electrodes of a liquid crystal display.

Claims (12)

An etching liquid composition for etching a metal film comprising a copper layer and / or a copper alloy layer, wherein the etching liquid composition comprises copper (II) ions, β-alanine and water. The method of claim 1,
The etching liquid composition whose pH is 8.5-11. 3. The method according to claim 1 or 2,
The etching liquid composition whose volume molar concentration of copper (II) ion is 0.01-0.6 mol / l. 3. The method according to claim 1 or 2,
The etching liquid composition whose volume molar concentration of (beta) -alanine is 0.5-3.0 mol / l. 3. The method according to claim 1 or 2,
Etching liquid composition comprising iodic acid. The method of claim 1,
The etching liquid composition whose pH is 8.5-11, Comprising: 0.01-0.6 mol / l of copper (II) ions, 0.5-3.0 mol / l of (beta) -alanine, 0.01-1.0 mol / l of iodic acid, and water. 3. The method according to claim 1 or 2,
Etching liquid composition which does not contain 1 type (s) or 2 or more types of compounds chosen from the group which consists of ethylenediamine, ethylenediamine tetraacetic acid, glycine, and L-alanine. An etching method comprising etching a metal film including a copper layer and / or a copper alloy layer using the etching solution composition according to claim 1. The method of claim 8,
An etching method wherein the metal film is a single layer film of a copper layer or a copper alloy layer or a laminated film including at least one copper layer or a copper alloy layer. The method of claim 9,
An etching method in which the metal film is a laminated film further comprising a layer made of a material which can be oxidized by copper (II) ions. 11. The method of claim 10,
An etching method wherein the material which can be oxidized by copper (II) ions is molybdenum. The method according to any one of claims 8 to 11,
An etching method in which a metal film is formed on a glass substrate, a Si wafer, or an oxide semiconductor.

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