TWI542733B - Etching solution composition for etching copper-based metal layer, method of manufacturing an array substrate for a liquid crystal display, method of etching a copper-based metal layer and array substrate for a liquid crystal display - Google Patents

Description

Etching solution composition for etching a copper-based metal layer, method for manufacturing the same, and method for etching the copper-based metal layer and liquid crystal thereof Display array substrate

The present invention relates to an etching solution composition for etching a copper-based metal layer, a method of manufacturing an array substrate using the liquid crystal display, a method of etching a copper-based metal layer, and an array substrate of a liquid crystal display.

A method of forming a metal wiring on a substrate of a liquid crystal display generally includes forming a metal layer by sputtering, coating a photoresist, performing exposure and development to form a photoresist on the selected region, and performing etching, and before each of the above processes Or after the cleaning process. An etching process is performed to leave a metal layer on the selected region using the photoresist as a mask, and the etching process may include dry etching using a plasma or wet etching using an etching solution composition.

The recent focus of such liquid crystal displays is on the resistance of metal wiring, because in the case of thin film transistor liquid crystal displays (TFT-LCDs), the problem of delaying the resistance of the resistors and capacitors (RC) is increased to increase the size of the panel and obtain High resolution is critical, where the RC signal delay is primarily caused by resistance. Therefore, in order to reduce the RC signal delay (reducing the RC signal delay is necessary to increase the size of the TFT-LCD), it is necessary to develop a low-resistance material.

For this reason, chromium (Cr, resistivity: 12.7 × 10 -8 Ωm), molybdenum (Mo, resistivity: 5 × 10 -8 Ωm), aluminum (Al, resistivity: 2.65 × 10 -8 Ωm), and alloys thereof are generally used. However, these metals have high electrical resistance, so it is difficult to use these metals for gate wiring and data wiring of large-sized TFT-LCDs. Therefore, a low-resistance metal layer, such as a copper-based metal layer such as a copper layer and a copper-molybdenum layer, and an etching solution composition are subjected to Note. However, currently known etching solution compositions for etching copper-based metals are not satisfactory to the user and require research and development to improve their performance.

A conventional etching solution containing hydrogen peroxide can wet-etch a metal multilayer structure including copper or a copper alloy and a molybdenum or molybdenum alloy in batches. However, when the metal layer is etched, metal ions and particularly copper ions therein are dissolved, resulting in an increase in the decomposition rate of hydrogen peroxide, which in turn causes overheating, and significantly deteriorates the stability of the etching solution.

Further, in the case of a metal multilayer, the difference between the rate of etching the copper layer with hydrogen peroxide and the rate of etching the molybdenum alloy layer with the fluorine compound due to the electrical effect (the difference is the concentration of the dissolved metal ion) The increase is proportional, so the interface between the two bonded metal layers may be deformed, resulting in poor etching performance.

Accordingly, the present invention is in mind the above problems in the related art, and an object of the present invention is to provide an etching solution composition for etching a copper-based metal layer, whereby when wet etching includes copper or a copper alloy and molybdenum or When the metal multilayer structure of the molybdenum alloy is used, regardless of the amount of the metal ions, a tapered profile having excellent linearity can be formed, and overheating due to an increase in the decomposition rate of hydrogen peroxide can be suppressed, and further, after etching the metal layer, Leave a residue.

Another object of the present invention is to provide an etching solution composition for etching a copper-based metal layer capable of batch etching gate, gate wiring, source/drain, and data wiring, the gate The gate wiring, source/drain and data wiring constitute a thin film transistor (TFT) of the TFT-LCD.

It is still another object of the present invention to provide a method of etching a copper-based metal layer using the above etching solution composition and a method of manufacturing an array substrate of a liquid crystal display.

In order to achieve the above object, the present invention provides an etching solution composition for etching a copper-based metal layer, the etching solution composition comprising A) 5 to 25 wt% hydrogen peroxide (H ₂ ) based on the total weight of the etching solution composition. O ₂ ), B) 0.01 to 1.0 wt% of the fluorine-containing compound, C) 0.1 to 5 wt% of the pyrrolyl compound, D) 0.1 to 10.0 wt% of one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof, E) 0.1 to 5 wt% of the phosphate compound and F) the balance of water.

The present invention further provides a method of etching a copper-based metal layer, comprising: I) forming a copper-based metal layer on a substrate; II) selectively forming a photo-reactive material on the copper-based metal layer; and III) utilizing the present invention according to the present invention The etching solution composition etches the copper-based metal layer.

The present invention further provides a method of manufacturing an array substrate of a liquid crystal display, comprising: a) forming a gate wiring on the substrate; b) forming a gate insulating layer on the substrate including the gate wiring; c) forming a semiconductor on the gate insulating layer a layer; d) forming a source and a drain on the semiconductor layer; and e) forming a pixel electrode connected to the drain, wherein a) includes forming a copper-based metal layer on the substrate and etching the copper using the etching solution composition according to the present invention A base metal layer, thereby forming a gate wiring, and d) including forming a copper-based metal layer on the semiconductor layer, and etching the copper-based metal layer with the etching solution composition according to the present invention, thereby forming a source and a drain.

Further, the present invention provides an array substrate of a liquid crystal display comprising one or more selected from the group consisting of a gate wiring and a source/drain which are etched using the etching solution composition according to the present invention.

The invention will be specifically described below.

The invention relates to an etching solution composition for etching a copper-based metal layer, comprising A) 5 to 25 wt% hydrogen peroxide (H ₂ O ₂ ); B) 0.01 to 1.0 wt% fluorine-containing compound; C) 0.1 to 5 wt. % pyrrolyl compound; D) 0.1 to 10.0% by weight of one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof; E) 0.1 to 5 wt% of a phosphate compound; and F) the balance of water.

In the present invention, the copper-based metal layer contains copper as a component of the layer, and has a form of a single layer and a form of a multilayer including a double layer. For example, a single layer of copper or a copper alloy, and a multilayer structure including a copper molybdenum layer, a copper molybdenum alloy layer, and the like are used. The structure of the copper-molybdenum layer includes a molybdenum layer and a copper layer formed on the molybdenum layer. Further, the structure of the copper-molybdenum alloy layer includes a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer. . The molybdenum alloy layer is made of an alloy of one or more of molybdenum and a group selected from the group consisting of titanium (Ti), tantalum (Ta), chromium (Cr), nickel (Ni), and niobium (Nd). And indium (In).

In the etching solution composition according to the present invention, A) hydrogen peroxide (H ₂ O ₂ ) is mainly used for etching the copper-based metal layer in an amount of 5 to 25 wt% based on the total weight of the etching solution composition. If A) the content of hydrogen peroxide is less than 5% by weight, the copper-based metal cannot be etched, or the etching rate becomes very low. On the other hand, if the content of the hydrogen peroxide exceeds 25% by weight, the entire etching rate may increase, making it difficult to control the process.

In the etching solution composition according to the present invention, B) the fluorine-containing compound means a compound which dissociates in water to generate fluorine ions. Also, B) the fluorine-containing compound has the effect of removing the residue, and the residue is simultaneously A solution of etching the copper layer and the molybdenum layer is inevitably produced. B) The amount of the fluorine-containing compound is 0.01 to 1.0% by weight based on the total weight of the composition of the etching solution. If the content of the B) fluorine-containing compound is less than 0.01% by weight, an etching residue may be formed. On the other hand, if the content of the fluorine-containing compound exceeds 1.0% by weight, the rate at which the glass substrate is etched may be greatly increased.

As the B) fluorine-containing compound, any material in the art can be used without particular limitation as long as the material can dissociate fluoride ions or polyatomic fluoride ions in a solution. The fluorine-containing compound may include a compound selected from the group consisting of ammonium fluoride (NH ₄ F), sodium fluoride (NaF), potassium fluoride (KF), ammonium hydrogen fluoride (NH ₄ FHF), sodium hydrogen fluoride (NaFHF), and potassium hydrogen fluoride ( Any one of the groups consisting of KFHF), or a mixture of two or more.

In the etching solution composition according to the present invention, C) a pyrrolyl compound is used to adjust the rate of etching the copper-based metal and reduce the CD (Critical Dimension) loss of the pattern, thereby increasing the process margin. C) The amount of the pyrrolyl compound is from 0.1 to 5% by weight based on the total weight of the composition of the etching solution. If the content of the C) pyrrolyl compound is less than 0.1% by weight, the etching rate may be increased to cause excessive CD loss. Conversely, if the content of the pyrrolyl compound exceeds 5% by weight, the rate of etching copper may be reduced, the rate of etching the molybdenum or molybdenum alloy may increase, and the molybdenum or molybdenum alloy may be excessively etched to cause under-cut. The phenomenon.

C) Examples of the pyrrolyl compound may include aminotetrazole, benzotriazole, tolytriazole, pyrazole, pyrrole, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-aminoimidazole, 4-methylimidazole, 4- Ethyl imidazole and 4-propylimidazole, etc., these may be used singly or in the form of a mixture of two or more.

In the etching solution composition according to the present invention, D) one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof for sequestering copper ions dissolved in an etching solution when etching a copper layer, thereby suppressing copper ions The activity, thereby preventing the decomposition of hydrogen peroxide. When the activity of the copper ions is lowered in the manner described, the etching solution can stably perform the process. D) The amount of one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof is from 0.1 to 10.0% by weight based on the total weight of the composition of the etching solution. If the content of D) one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof is less than 0.1% by weight, the etching uniformity may be lowered, and the decomposition of hydrogen peroxide may be accelerated. On the other hand, if the content exceeds 10.0% by weight, the etching rate may excessively increase.

In one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof, a typical example of a phosphonic acid derivative is 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), a typical salt of a phosphonic acid derivative. An example is the sodium or potassium salt of 1-hydroxyethylidene-1,1-diphosphonic acid.

In the etching solution composition according to the present invention, the E) phosphate compound makes the tapered profile good, and can reduce the electrical effect and the difference in etching rate between the copper layer and the molybdenum alloy layer, the difference with the metal ion The increase in concentration is proportional. Thereby, even if there is an excessive amount of metal ions, the interface between the two bonded metal layers can be prevented from being deformed, thereby obtaining a good etching profile.

E) The amount of the phosphate compound is 0.1 to 5 wt% based on the total weight of the composition of the etching solution. If the content of the phosphate compound is less than 0.1% by weight, it cannot be obtained well with a high concentration of metal ions. Conical contour. On the other hand, if the content exceeds 5 wt%, the rate at which the molybdenum alloy layer is etched may be remarkably lowered to increase the residue.

As the E) phosphate compound, any material in the art can be used without particular limitation as long as the material can dissociate phosphate ions in a solution. The phosphate compound may include a salt selected from the group consisting of ammonium dihydrogen phosphate, sodium dihydrogen phosphate, calcium dihydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, disodium hydrogen phosphate, calcium phosphate dibasic, and hydrogen phosphate. One or more of the groups consisting of potassium.

In the etching solution composition according to the present invention, F) water used as a residue is not particularly limited, but the water may include deionized water. More particularly useful is that the resistivity of the deionized water (degree of ions removed from the water) is 18 MΩ/cm or more.

Likewise, the etching solution composition of the present invention may further include a surfactant for reducing surface tension to increase etching uniformity. Here, the surfactant is not particularly limited as long as the surfactant is resistant to the etching solution composition according to the present invention and has compatibility. The surfactant may include any one or two or more selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, and a polyol surfactant. mixture.

Also, in addition to the above components, the etching solution composition according to the present invention may further include typical additives, and examples of such additives may include a chelating agent, an anticorrosive agent, and the like.

The etching solution used in the present invention can be prepared by a typical method, which comprises A) hydrogen peroxide (H ₂ O ₂ ), B) a fluorine-containing compound, C) a pyrrolyl compound, D) selected from a phosphonic acid derivative and One or more compounds of the salt, E) a phosphate compound, and F) the balance of water, and the purity of the solution may be suitable for semiconductor technology.

The etching solution composition according to the present invention can be used for batch etching of gate, gate wiring, source/drain and data wiring of a liquid crystal display made of a copper-based metal.

In addition, the present invention provides a method of etching a copper-based metal layer, comprising at least the steps of: I) forming a copper-based metal layer on a substrate; II) selectively forming a photo-reactive material on the copper-based metal layer; and III) The copper-based metal layer is etched using the etching solution composition according to the present invention.

In the etching method according to the present invention, the photoreactive material may be a typical photoresist which can be selectively left by a typical exposure and development process.

Further, the present invention provides a method of manufacturing an array substrate of a liquid crystal display, comprising at least the steps of a) forming a gate wiring on a substrate; b) forming a gate insulating layer on a substrate having a gate wiring; c) insulating the gate Forming a semiconductor layer on the layer; d) forming a source and a drain on the semiconductor layer; and e) forming a pixel electrode connected to the drain, wherein a) may include forming a copper-based metal layer on the substrate, and utilizing the present invention in accordance with the present invention The etching solution composition etches the copper-based metal layer to form a gate wiring, and d) may include forming a copper-based metal layer on the semiconductor layer, and etching the copper-based metal layer using the etching solution composition of the present invention to form a source and Bungee jumping.

The array substrate of the liquid crystal display may be a thin film transistor (TFT) array substrate.

The following examples are presented to illustrate and not to limit the invention, which may help to better understand the invention.

Example Preparation of etching solution composition

The etching solution compositions of Examples 1 to 6 were prepared using the components shown in Table 1 below.

Etching of copper-based metal layers

A molybdenum-titanium (Mo-Ti) layer is deposited on a glass substrate (100 mm × 100 mm), a copper layer is deposited on the Mo-Ti layer, and then photolithography is performed to form a photoresist having a predetermined pattern on the substrate, after that, Copper-based metal layers (Cu monolayer and Cu/Mo-Ti bilayer) were etched using each of the etching solution compositions of Examples 1-6.

An etching process is performed using a jet etching machine (ETCHER (TFT), commercially available from SEMES), in which the temperature of the etching solution composition is set to about 30 ° C, which may be based on other process conditions and factors The requirements vary appropriately. Although the etching time varies depending on the etching temperature, the etching time is set to about 30-180. second.

Performance evaluation of etching solution composition

A cross-sectional view of the etched copper-based metal layer in the above etching process was observed using SEM (S-4700, available from Hitachi). The results are shown in Table 2 below.

Also, in order to evaluate the degree of superheat by chain decomposition of hydrogen peroxide in the presence of metal ions (especially copper ions), 3000 ppm of Cu powder was eluted in the etching solutions of Examples 1 to 6, after which the etching solution was allowed. Stay for a predetermined period of time and measure its temperature. The results are shown in Table 2 below.

As is apparent from Table 2, all of the etching solutions of Examples 1 to 6 exhibited good etching properties. As shown in FIG. 1, using the embodiment 1 The etched solution composition etched copper-based metal layer exhibits a good tapered profile. Also, as shown in FIGS. 2 and 3, in the case of etching the copper-based metal layer using the etching solution composition of Example 4, excellent linearity was obtained, and no etching residue was left. Further, as is apparent from Table 2, when the etching solutions of Examples 1 to 6 were used, even if 3000 ppm of Cu was eluted, the temperature was only raised to 36.1 ° C, which greatly improved the overheat stability.

Comparative Example 1 and Example 4: Evaluation of several processing sheets with an etching solution composition

Using the etching solution composition of Comparative Example 1 shown in Table 3 below, which is a conventional etching solution composition, and the etching solution composition according to Example 4 of the present invention, the maximum temperature and residual were measured at different Cu concentrations. Material generation and etching profile. Thus, since the chain decomposition of hydrogen peroxide is proportional to the increase in copper concentration, the maximum temperature represents the maximum value of the temperature change of the etching solution.

As is apparent from Table 3, FIG. 4 and FIG. 5, when the elution of at least 4000 ppm of Cu, the temperature of the conventional etching solution composition of Comparative Example 1 was raised to 99.2 ° C, undesirably and significantly changing the stability. Poor, and due to the electrical effect and the difference between the rate at which the copper layer is etched with hydrogen peroxide and the rate at which the molybdenum alloy layer is etched with the fluorine compound, the interface is deformed, resulting in a poor etching profile. However, when the etching solution of Example 4 was used, as shown in Table 3, Fig. 6, and Fig. 7, even if 6000 ppm of Cu was eluted, no overheating occurred, and no residue was obtained, and a good etching profile was obtained. Therefore, the etching solution composition according to Example 4 of the present invention can be used until 6000 ppm of Cu is eluted.

As described above, the present invention provides a method of manufacturing an array substrate of a liquid crystal display. When etching a metal multilayer comprising copper or a copper alloy and a molybdenum or molybdenum alloy, the etching solution composition according to the present invention can be subjected to batch etching and patterning. Further, even if the concentration of the metal ions is increased, the etching solution can be prevented from being overheated, thereby maintaining its stability, and the interface is not deformed due to the electrical effect and the difference in the etching rate between the metal layers. Moreover, a linearly excellent tapered profile can be obtained and does not remain after etching. The residue is left, and therefore, the etching solution composition according to the present invention has no problems such as short circuit, poor wiring, and reduced brightness.

Also, when fabricating an array substrate of a liquid crystal display, the etching solution composition according to the present invention can batch-etch gate, gate wiring, source/drain, and data wiring, thereby simplifying the etching process and maximizing the process yield.

Therefore, the etching solution composition according to the present invention can be used very effectively for manufacturing an array substrate of a liquid crystal display, thereby obtaining a large-sized screen and a high-brightness circuit.

Although the preferred embodiments of the present invention have been disclosed for the purposes of illustration, it will be understood by those skilled in the art that various changes and additions can be made without departing from the scope and spirit of the invention as disclosed in the appended claims. And replacement.

The above and other objects, features and further advantages of the present invention will become apparent from

1 shows a scanning electron microscope (SEM) image of a cross section of a copper-based metal layer in which the copper-based metal layer is etched by the etching solution composition (Example 1) according to the present invention.

2 and 3 respectively show SEM images of the entire etch profile and surface around the copper wiring after etching the copper-based metal layer using the etching solution composition (Example 4) according to the present invention.

4 and 5 respectively show SEM images of the cross section and the entire etching profile after etching the Cu/Mo-Ti glass with 4,000 ppm of Cu using the etching solution composition of Comparative Example 1.

6 and 7 show the etching solution using the embodiment 4, respectively. SEM image of the etched cross section and the entire etch profile after the composition etched Cu/Mo-Ti glass at 6,000 ppm Cu.

Claims (9)

An etching solution composition for etching a copper-based metal layer, the etching solution composition comprising: A) 5 to 25 wt% hydrogen peroxide; and B) 0.01 to 1.0 wt%, based on the total weight of the etching solution composition a fluorine-containing compound; C) 0.1 to 5 wt% of a pyrrolyl compound; D) 0.1 to 10.0 wt% of one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof; E) 0.1 to 5 wt% of a phosphate compound; a balance of water; the D) one or more compounds selected from the group consisting of phosphonic acid derivatives and salts thereof are selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid, 1-hydroxyethylidene-1,1 One or more of the group consisting of a sodium salt of a diphosphonic acid and a potassium salt of 1-hydroxyethylidene-1,1-diphosphonic acid. The etching solution composition for etching a copper-based metal layer according to claim 1, wherein the B) fluorine-containing compound is selected from the group consisting of NH ₄ FHF, KFHF, NaFHF, NH ₄ F, KF, and NaF. One or more of the groups. The etching solution composition for etching a copper-based metal layer according to claim 1, wherein the C) pyrrolyl compound is selected from the group consisting of aminotetrazole, benzotriazole, tolyltriazole, pyrazole, One of the group consisting of pyrrole, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-aminoimidazole, 4-methylimidazole, 4-ethylimidazole, and 4-propylimidazole Or multiple. Such as the copper fund for etching as described in claim 1 An etching solution composition of the genus layer, wherein the E) phosphate compound is selected from the group consisting of ammonium dihydrogen phosphate, sodium dihydrogen phosphate, calcium dihydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, disodium hydrogen phosphate, and phosphoric acid. One or more of the group consisting of calcium hydrogen and dipotassium hydrogen phosphate. An etching solution composition for etching a copper-based metal layer according to claim 1, wherein the copper-based metal layer is a single layer of copper or a copper alloy, including a molybdenum layer and copper formed on the molybdenum layer a layer of copper molybdenum layer, or a copper-molybdenum alloy layer comprising a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer. A method of manufacturing an array substrate of a liquid crystal display, comprising the steps of: a) forming a gate wiring on a substrate using an etching solution composition; b) forming a gate insulating layer on the substrate including the gate wiring; c) Forming a semiconductor layer on the gate insulating layer; d) forming a source and a drain on the semiconductor layer using an etching solution composition; and e) forming a pixel electrode connecting the drain; the a) being included on the substrate Forming a copper-based metal layer, and etching the copper-based metal layer with the etching solution composition to form the gate wiring; the d) includes forming a copper-based metal layer on the semiconductor layer, and utilizing the Etching the solution composition to etch the copper-based metal layer to form the source and the drain; the etching solution composition comprises A) 5 to 25 wt% based on the total weight of the etching solution composition Hydrogen peroxide, B) 0.01~1.0wt% fluorine-containing compound, C) 0.1~5wt% pyrrolyl compound, D)0.1~10.0 The wt% is selected from one or more compounds of a phosphonic acid derivative and a salt thereof, E) 0.1 to 5 wt% of a phosphate compound, and F) the balance of water; the D) is selected from the group consisting of a phosphonic acid derivative and a salt thereof Or a plurality of compounds are selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid, sodium salt of 1-hydroxyethylidene-1,1-diphosphonic acid, and 1-hydroxyethylidene-1,1-diphosphine One or more of the group consisting of potassium salts of acids. The method of manufacturing an array substrate of a liquid crystal display according to claim 6, wherein the array substrate of the liquid crystal display is a thin film transistor array substrate. A method of etching a copper-based metal layer, comprising: I) forming a copper-based metal layer on a substrate; II) selectively forming a photo-reactive material on the copper-based metal layer; and III) utilizing as in the patent application The etching solution composition described in the item etches the copper-based metal layer. An array substrate of a liquid crystal display comprising one or more selected from the group consisting of a gate, a gate line, a source and a drain, and a data wiring etched using the etching solution composition as described in claim 1 of the patent application.