KR101669772B1

KR101669772B1 - Composition for etching copper

Info

Publication number: KR101669772B1
Application number: KR1020150162226A
Authority: KR
Inventors: 김윤철; 박종희; 권윤경; 장욱
Original assignee: 오씨아이 주식회사
Priority date: 2015-11-19
Filing date: 2015-11-19
Publication date: 2016-10-27

Abstract

The present invention relates to a composition for etching copper and, more specifically, relates to a composition for etching copper, which can restrict occurrence of copper sediment from a composition for etching by improving stability of coupling chelate formed between copper and organic matter.

Description

COMPOSITION FOR ETCHING COPPER [0002]

The present invention relates to a copper etching composition, and more particularly, to a copper etching composition capable of inhibiting the generation of copper precipitate from an etching composition by increasing the stability of a chelate bond formed between copper and an organic compound.

Semiconductor devices, display devices, printed boards, IC cards, and the like generally form metal thin film elements, electrode wiring elements and the like by patterning a metal thin film or the like on a substrate.

As a processing technique for patterning such a metal thin film into a fine structure such as a wiring, a photoresist pattern formed on the surface of the metal thin film by a photolithography technique is used as a mask, and a wet etching And dry etching such as ion etching or plasma etching.

Of these, the wet etching method is economically advantageous because it does not require an expensive apparatus and uses relatively inexpensive chemicals unlike the dry etching method. It also has the advantage of being able to provide a uniform etch to large area and / or substrates of various shapes. Due to the above advantages, wet etching is mainly used as a thin film pattern manufacturing method at present.

In recent years, copper, which has low electrical resistance and is easy to process in a thin film pattern, is preferred as a material used for metal thin film devices, electrode wirings, and other devices used in semiconductor and liquid crystal display devices.

A copper etchant (or a composition for copper etching) is essentially used for the above-described wet etching, and most copper etchants are widely used for hydrogen peroxide-based etchants which are excellent in cost and performance.

Hydrogen peroxide etchants are produced by mixing hydrogen peroxide with chelating agents and other additives. When excessive copper dissolves into the etchant as the etching of copper proceeds, unstable hydrogen peroxide decomposes to deteriorate the performance of the etchant. .

Further, there has been a problem that some copper which has been dissolved in the etchant precipitates in the form of solid or sludge-like precipitate as hydrogen peroxide decomposes.

Such a copper precipitate may cause problems such as inhibiting the performance of the hydrogen peroxide-based etchant in the chamber in which the etching of the copper is carried out, or precipitating on the piping or the like, thereby obstructing the flow of the liquid.

Therefore, in the past, the period of replacing with a new etchant was shortened in order to prevent an excessive amount of copper dissolved to decompose hydrogen peroxide and to prevent copper precipitates from being generated due to decomposition of hydrogen peroxide.

An object of the present invention is to provide a copper etching composition capable of increasing the stability of a chelate bond formed between copper and an organic substance and suppressing the generation of copper precipitate from the etching composition.

Another object of the present invention is to provide a copper etching composition capable of preventing dissolved copper from precipitating as a precipitate when hydrogen peroxide is decomposed when an excessive amount of copper is dissolved into the etching composition.

It is another object of the present invention to provide a composition for copper etching which can increase the solubility of copper in an etching composition to reduce the possibility of decomposition of hydrogen peroxide by copper.

In order to solve the above technical problem,

According to one aspect of the present invention, hydrogen peroxide; At least one chelating agent selected from acetic acid chelating agents, sulfonic acid chelating agents and phosphonic acid chelating agents; A chelating stabilizer represented by the following formula (1); And water, may be provided.

[Chemical Formula 1]

Here, R ₁ to R ₃ represent C ₁ -C ₃ Alkyl.

In particular, when the number of carbon atoms of R ₂ and R ₃ is larger than 3, since the distance between the central atom is nitrogen and the terminal oxygen of both carboxyl groups far it may fall more chelating effect of copper by chelating stabilizing agent, R ₂ And the number of carbon atoms of R ₃ is preferably 3 or less.

The composition for copper etching according to an embodiment of the present invention comprises 5 to 40 parts by weight of hydrogen peroxide; 0.1 to 2 parts by weight of a chelating agent; 0.1 to 0.4 parts by weight of a chelating stabilizer; And residual water.

Here, the weight ratio of the chelating agent to the chelating stabilizer in the copper etching composition is preferably 1: 0.1 to 1: 0.4.

The acetic acid chelating agent may be at least one selected from the group consisting of nitrilotriacetic acid, iminodiacetic acid, methyliminodiacetic acid, hydroxyethyliminodiacetic acid, diethylenetriamine pentaacetic acid, ethylenediaminetetraacetic acid, N-hydroxyethylethylenediamine tetraacetic acid, Diamine tetraacetic acid and triethylenetetraamine hexaacetic acid. The sulfonic acid chelating agent may be at least one selected from the group consisting of sulfonic acid, methanesulfonic acid, methanesulfonic acid, ethanesulfonic acid, ethanesulfonic acid, P-toluenesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid, chlorobenzenesulfonic acid and ethylbenzenesulfonic acid.

In addition, the phosphonic acid-based chelating agent may be at least one selected from ethylenediamine tetramethylene phosphonic acid, diethylene triamine pentamethylene phosphonic acid, hydroxyethylidene diphosphonic acid and aminotrimethylene phosphonic acid.

In addition, the maximum concentration of soluble copper ions in the composition for copper etching according to an embodiment of the present invention is 6000 ppm or more, and stable etching properties can be realized without decomposition of hydrogen peroxide and / or generation of copper precipitate.

The composition for copper etching according to the present invention may further contain a chelate stabilizer to increase the stability of a chelate bond formed between copper and an organic material, thereby inhibiting the formation of copper precipitate from the etching composition.

Further, the copper etching composition according to the present invention can further increase the maximum concentration of soluble copper ions in the etching composition due to the additional chelating effect of the chelate stabilizer, thereby preventing the decomposition of hydrogen peroxide by excessive copper .

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art to which the invention pertains. Only. Like reference numerals refer to like elements throughout the specification.

Hereinafter, the composition for copper etching according to the present invention will be described in detail.

The composition for copper etching according to one aspect of the present invention may include hydrogen peroxide, chelating agent, chelating stabilizer and water as a hydrogen peroxide type etchant for wet etching of copper.

Here, the chelating agent may be at least one chelating agent selected from acetic acid chelating agents, sulfonic acid chelating agents and phosphonic acid chelating agents.

More specifically, the acetic acid chelating agent is selected from nitrilotriacetic acid, iminodiacetic acid, methyliminodiacetic acid, hydroxyethyliminodiacetic acid, diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, N-hydroxyethylethylenediamine tetraacetic acid , Methylethylenediamine tetraacetic acid, and triethylenetetraamine hexaacetic acid.

The sulfonic acid chelating agent may also be at least one selected from sulfonic acid, methane sulfonic acid, methane disulfonic acid, ethane sulfonic acid, ethane disulfonic acid, propane sulfonic acid, benzene sulfonic acid, chlorobenzene sulfonic acid and ethylbenzene sulfonic acid. have.

In addition, the phosphonic acid-based chelating agent may be at least one selected from ethylene diamine tetramethylene phosphonic acid, diethylene triamine pentamethylene phosphonic acid, hydroxyethylidenediphosphonic acid and aminotrimethylene phosphonic acid.

For example, iminodiacetic acid, which can be used as a chelating agent for a copper etching composition according to an embodiment of the present invention, has a form in which two carboxyl groups are bonded to nitrogen as a central atom as shown in the following formula (2).

(2)

After the protons which are acidic in the carboxyl groups present at both terminals of iminodiacetic acid are removed, the metal (M, for example, copper) forms a chelate bond with nitrogen of the central atom and oxygen of the two carboxyl groups .

(3)

Referring to Formula (3), the metal (M) forms three bonds with one nitrogen atom and two oxygen atoms in one molecule of iminodiacetic acid, and the metal (M) By additionally forming one bond with nodiacetic acid, a stable chelate bond can be maintained.

[Chemical Formula 4]

At this time, as the amount of copper dissolved in the composition for copper etching is increased, when iminodiacetic acid is consumed as a chelating agent, the amount of copper forming an unstable chelating bond represented by the general formula (3) also increases.

The chelate bond of the structure represented by the general formula (3) can be precipitated as a precipitate in the form of copper-iminodiacetic acid when the metal (M) is unstably chelated and left in this state.

In addition, since the solubility of a chelating agent such as iminodiacetic acid is also limited, it is extremely difficult to increase the concentration of the chelating agent indefinitely to form a chelate bond as shown in Chemical Formula (4).

Thus, according to one embodiment of the present invention, there is provided a chelating stabilizer represented by the following formula (1) so as to be able to form a stable chelate bond represented by formula (4) even when the amount of copper dissolved in the copper etching composition is increased .

[Chemical Formula 1]

Here, R ₁ to R ₃ represent C ₁ -C ₃ Alkyl, that is, an alkyl chain having 1 to 3 carbon atoms.

The chelating stabilizer represented by the general formula (1) may be prepared by reacting a metal (M) (for example, copper) after the acidic proton of the two carboxyl groups bonded to the nitrogen atom, which is a central atom, in a similar manner to iminodiacetic acid, To form a chelate bond.

[Chemical Formula 5]

At this time, when the number of carbon atoms of R ₂ and R ₃ is greater than 3, the additional chelating effect of copper by the chelate stabilizer may be deteriorated because the distance between the central atom of nitrogen and the terminal oxygen of both carboxyl groups is decreased. ₂ and R ₃ is preferably 3 or less.

In addition, the chelate stabilizer can prevent the generation of copper precipitates by providing an additional chelate bond to the copper that forms an unstable chelate bond as shown in the following formula (6), as well as a chelate stabilizer which is consumed in order to form additional chelate bond with copper The amount can be reduced.

[Chemical Formula 6]

According to one embodiment of the present invention, the composition for copper etching may comprise 5 to 40 parts by weight of hydrogen peroxide, 1 to 2 parts by weight of chelating agent, 0.1 to 0.4 parts by weight of chelating stabilizer and the balance water.

In particular, the weight ratio of the chelating agent to the chelating stabilizer in the copper etching composition is preferably from 1: 0.1 to 1: 0.4.

When the ratio of the chelating agent to the chelating stabilizer is less than 1: 0.1, that is, when the content of the chelating stabilizer relative to the content of chelating agent in the copper etching composition is excessively small, the chelating agent and the unstable chelating agent The effect of stabilizing may be insignificant by providing an additional chelate bond to the copper forming the bond.

Therefore, when the content of the chelating stabilizer relative to the chelating agent content in the copper etching composition is excessively small, it is highly possible that copper ions forming an unstable chelate bond precipitate in the form of a copper precipitate.

On the other hand, when the ratio of the chelating agent to the chelating stabilizer is 1: 0.4 or more, that is, the content of the chelating stabilizer relative to the content of the chelating agent in the copper etching composition is higher than the predetermined standard, There is a possibility that the chelating agent and / or the chelating stabilizer are not completely dissolved and are present in the form of a precipitate, since the amount of the chelating agent and chelating stabilizer soluble in the chelating agent is limited.

In particular, in the case of the chelate stabilizer represented by the formula (1), since the solubility of the chelating agent exemplified in the present invention is lower than that of the chelating agent exemplified in the present invention, it is extremely difficult to increase the concentration of the chelate stabilizer indefinitely for the stabilizing effect of the chelate bond.

In particular, the composition for copper etching according to an embodiment of the present invention can solve the problem of precipitation of copper due to unstable chelate bonds due to the chelate bond of the copper ion by the chelating agent and the additional chelate bond by the chelate stabilizer, In addition, by additionally supplying a chelating stabilizer, the possibility of consuming chelating agent of two molecules for chelate bonding with chelate ion of one copper ion is remarkably reduced, and even if the same amount of chelating agent is included in one embodiment of the present invention The copper etching composition according to the present invention has a high maximum concentration of soluble copper ions so as to increase the lifetime of the copper etching composition and prevent the decomposition of hydrogen peroxide by an excessive amount of copper.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

Copper For etching Composition of composition

Table 1 below shows the compositions of copper etching compositions according to Examples and Comparative Examples.

division Hydrogen peroxide Chelating agent Other ingredients Example 1 23 wt% Iminodiacetic acid
2wt% Formula 7
0.2 wt% Example 2 23 wt% Iminodiacetic acid
1wt% 8
0.4wt% Example 3 23 wt% N-methyliminodiacetic acid
1wt% Formula 7
0.2 wt% Example 4 23 wt% N-methyliminodiacetic acid
2wt% 8
0.4wt% Example 5 23 wt% Methanesulfonic acid
1wt% Formula 7
0.2 wt% Example 6 23 wt% Benzenesulfonic acid
1wt% Formula 7
0.2 wt% Example 7 23 wt% Hydroxyethylidene diphosphonic acid
1wt% Formula 7
0.2 wt% Example 8 23 wt% Ethylenediamine tetramethylenephosphonic acid
1wt% Formula 7
0.2 wt% Comparative Example 1 23 wt% Iminodiacetic acid
1wt% - Comparative Example 2 23 wt% Iminodiacetic acid
2wt% - Comparative Example 3 23 wt% Iminodiacetic acid
2wt% N-methyliminodiacetic acid
0.2 wt% Comparative Example 4 23 wt% Iminodiacetic acid
2wt% N, N-bis (carboxymethyl) ethanolamine
0.3 wt% Comparative Example 5 23 wt% Iminodiacetic acid
2wt% Triethylenetetraamine hexaacetic acid
0.25 wt% Comparative Example 6 23 wt% Iminodiacetic acid
2wt% Formula 7
0.05 wt% Comparative Example 7 23 wt% Methanesulfonic acid
1wt% - Comparative Example 8 23 wt% Methanesulfonic acid
1wt% N-methyliminodiacetic acid
0.2 wt% Comparative Example 9 23 wt% Hydroxyethylidene diphosphonic acid
1wt% - Comparative Example 10 23 wt% Hydroxyethylidene diphosphonic acid
1wt% N-methyliminodiacetic acid
0.2 wt%

* Remaining water included

(7)

[Chemical Formula 8]

Copper For etching Evaluation of composition characteristics

In order to evaluate the characteristics of the copper etching composition having the composition shown in Table 1, the compositions for copper etching according to the examples and the comparative examples were put in an experimental equipment of a spray type wet etching method (manufactured by KCTECH, model name: ETCHER (TFT) And the copper substrate having a thickness of 2000 ANGSTROM was etched when the temperature was maintained at 33 +/- 0.5 DEG C by heating.

The evaluation items for evaluating the stability of the composition for copper etching are whether or not precipitates are generated at the copper ion concentration of 6000 ppm and the concentration of the maximum soluble copper ion in the etching solution.

The results for the two evaluation items are shown in Table 2 below.

division Precipitate occurrence Maximum soluble copper ion concentration
(ppm) Example 1 radish 8000 Example 2 radish 7500 Example 3 radish 7000 Example 4 radish 8000 Example 5 radish 6000 Example 6 radish 6000 Example 7 radish 6000 Example 8 radish 6000 Comparative Example 1 U 5000 Comparative Example 2 U 6000 Comparative Example 3 U 7500 Comparative Example 4 U 8000 Comparative Example 5 U 9000 Comparative Example 6 U 7000 Comparative Example 7 U 4000 Comparative Example 8 U 5500 Comparative Example 9 U 5000 Comparative Example 10 U 6500

Examples 1 to 4 are copper etching compositions comprising an acetic acid chelating agent, Examples 5 and 6 are copper etching compositions comprising a sulfonic acid chelating agent, Examples 7 and 8 are phosphon Based chelating agent, wherein the chelate stabilizer represented by the general formula (7) or (8) is contained in an amount of 0.1 to 0.4 wt% based on the weight of the total copper etching composition in each of Examples 1 to 8.

On the other hand, Comparative Example 1 and Comparative Example 2 showed a composition for copper etching that contained only a chelating agent without a chelating stabilizer. As the chelating agent content increased, the maximum soluble copper ion concentration increased. However, Type precipitates were generated.

In addition, Comparative Examples 3 to 5 were prepared in the same manner as in Example 1 except for using copper acetylacetonate as an acetic acid chelating agent and further containing a component (for example, auxiliary clay) used as an additive for a copper etching composition When the composition further comprises N-methyliminodiacetic acid, N, N-bis (carboxymethyl) ethanolamine and triethylenetetraamine hexaacetic acid as the auxiliary chelating agent, the maximum soluble copper ion concentration of the copper etching composition is It was confirmed that the commercialization level reached 7500 to 9000 ppm.

However, it was confirmed that copper precipitates were generated as the etching according to Comparative Examples 3 to 5 proceeded. At this time, the generation of copper precipitates was observed even though the maximum soluble copper ion concentration of the copper etching composition was not reached.

This phenomenon is caused by the fact that the chelating agents N-methyliminodiacetic acid, N, N-bis (carboxymethyl) ethanolamine and triethylenetetraaminehexaacetic acid have different structures from those of the chelating stabilizer represented by the formula It is not possible to provide the effect of complementing the unstable chelate bond of the copper ion and the chelating agent like the stabilizer, and it is confirmed that the copper chelate forming the unstable chelate bond is precipitated in the form of precipitate.

In addition, the composition for copper etching according to Comparative Example 6 contained iminodiacetic acid as an acetic acid chelating agent and included a chelating stabilizer represented by Chemical Formula 7 as in the examples of the present invention. With the proviso that the chelating stabilizer content was less than 0.05 wt% of the total copper etching composition, which was less than the chelating stabilizer content included in the examples.

In the case of Comparative Example 6, as the etching progressed, copper precipitates were formed. This is because the content of the chelating stabilizer relative to the content of the chelating agent in the copper etching composition is excessively small, It was confirmed that the stabilizing effect was insignificant by providing an additional chelate bond to the copper forming the unstable chelate bond.

In addition to Comparative Example 7 and Comparative Example 9 comprising a sulfonic acid-based chelating agent or phosphonic acid-based chelating agent alone, Comparative Example 8 in which a sulfonic acid-based chelating agent and a supplemental chelating agent were mixed, and Comparative Example 8 in which a phosphonic acid- It was confirmed that the copper precipitate was generated even though the maximum soluble copper ion concentration of the composition for copper etching was not reached as the etching progressed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention as set forth in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

Claims

Hydrogen peroxide;
At least one chelating agent selected from acetic acid chelating agents, sulfonic acid chelating agents and phosphonic acid chelating agents;
A chelating stabilizer represented by the following formula (1); And
water;
A copper etching composition comprising:
Wherein the weight ratio of the chelating agent to the chelating stabilizer in the copper etching composition is from 1: 0.1 to 1: 0.4,
Copper etching composition:

[Chemical Formula 1]

Here, R ₁ to R ₃ are C ₁ -C ₃ alkyl.

The method according to claim 1,
5 to 40 parts by weight of the hydrogen peroxide;
1 to 2 parts by weight of the chelating agent;
0.1 to 0.4 parts by weight of said chelating stabilizer; And
Residual water;
/ RTI >
Composition for copper etching.

The method according to claim 1,
The acetic acid chelating agent may be at least one selected from the group consisting of nitrilotriacetic acid, iminodiacetic acid, methyliminodiacetic acid, hydroxyethyliminodiacetic acid, diethylenetriamine pentaacetic acid, ethylenediaminetetraacetic acid, N-hydroxyethylethylenediamine tetraacetic acid, Diamine tetraacetic acid, and triethylene tetraamine hexaacetic acid.
Composition for copper etching.

The method according to claim 1,
Wherein the sulfonic acid based chelating agent is at least one selected from the group consisting of sulfonic acid, methane sulfonic acid, methane disulfonic acid, ethane sulfonic acid, ethane disulfonic acid, propane sulfonic acid, benzene sulfonic acid, chlorobenzene sulfonic acid,
Composition for copper etching.

The method according to claim 1,
Wherein the phosphonic acid-based chelating agent is at least one selected from ethylenediamine tetramethylene phosphonic acid, diethylenetriaminepentamethylenephosphonic acid, hydroxyethylidene diphosphonic acid and aminotrimethylenephosphonic acid,
Composition for copper etching.

The method according to claim 1,
Wherein the maximum concentration of soluble copper ions in the copper etching composition is at least 6000 ppm,
Composition for copper etching.