KR101339316B1 - Etching solution for two layer of copper/molybdenum or three layer of molybdenum/copper/molybdenum without damage of glass substrate - Google Patents

Abstract

Photoresist is coated and exposed on a metal wiring material for gate, source, and drain electrodes constituting the TFT (Thin Film Transitor) of the liquid crystal display device, and then etched to desired pattern. An etching composition for a thin film transistor liquid crystal display device is disclosed. Such an etching composition is based on the total weight of the composition, 5 to 20% by weight of hydrogen peroxide, 0.1 to 5% by weight of etchants, 0.1 to 5% by weight of chelating agents, 0.1 to 5% by weight of ammonium compounds, 0.01 to 2 azole compounds Water is included so that the weight percent and total weight are 100 weight percent. The pH of this etching composition is adjusted to 1.0 to 3.5. According to the present invention, not only is it possible to collectively etch a copper / molybdenum film or a molybdenum / copper / molybdenum triple layer, but also eliminate the possibility of defects caused by etching of the glass substrate by fluoride. It does not occur and has a suitable etching rate, a suitable etching amount and an appropriate taper angle for the process.

Description

Etching solution for two layer of copper / molybdenum or three layer of molybdenum / copper / molybdenum without damage of glass substrate}

According to an embodiment of the present invention, a photoresist is coated and exposed on a metal wiring material for a gate, a source, and a drain electrode constituting a thin film transistor (TFT) of a liquid crystal display, and then etched to obtain a desired pattern ( It relates to an etching composition for a thin film transistor liquid crystal display device to obtain a pattern). More specifically, the present invention relates to an etching composition for a thin film transistor liquid crystal display device for etching copper / molybdenum double film or molybdenum / copper / molybdenum triple film at once.

In general, the liquid crystal display includes a liquid crystal panel including a thin film transistor substrate, a color filter substrate, and a liquid crystal layer injected between the two substrates. Wiring is formed in the thin film transistor substrate to transmit a signal to the liquid crystal layer. The wiring of the thin film transistor substrate includes a gate wiring and a data wiring. Here, the gate line includes a gate line to which a gate signal is applied and a gate electrode of the thin film transistor, and the data line is insulated from the gate line and the drain electrode and the source constituting the data electrode of the thin film transistor and the data line applying the data signal. An electrode. Such a wiring may be made of a metal single layer or an alloy single layer, but is often formed in multiple layers to compensate for the disadvantages of each metal or alloy and to obtain desired physical properties.

On the other hand, the process of forming the metal wiring on the substrate in the semiconductor device is typically a step by a metal film forming process by sputtering or the like, a photoresist forming process in a selective region by photoresist coating, exposure and development, and an etching process It comprises a washing process before and after an individual unit process. The etching process refers to a process of leaving a metal film in a selective region using a photoresist as a mask, and typically, dry etching using plasma or wet etching using an etching solution is used.

The resistance of the metal film used at this time is a factor that causes the electrical signal delay of the thin film transistor liquid crystal display device and has a direct effect on the high resolution and the panel size. In recent years, copper (Cu) has been in the spotlight as a metal wiring material having a low resistance value and having no large environmental problems in order to reduce the electrical signal delay of a thin film transistor liquid crystal display device.

However, copper has a disadvantage in that the adhesion between the glass film and the silicon film is poor, and thus it is difficult to be used as a single copper film. To compensate for the shortcomings of a single copper film, a multilayer film using copper as the main wiring metal film and a copper metal, titanium, molybdenum or molybdenum alloy with excellent adhesion to the glass film and the silicon film is used. Among them, a copper titanium film was used as a particularly popular material. Conventionally known etching solutions exist for this copper titanium double layer and many new etching solutions have been published. However, due to the special chemical properties of titanium membranes, there is a disadvantage in that etching is not possible unless fluorine ions are present. When fluorine ions are included in the etching solution, the glass substrate and various silicon layers (passivation layer composed of semiconductor layers and silicon nitride films) are also etched together, and there are many elements that may cause defects in the process.

Accordingly, research on molybdenum films that are easier to etch than titanium is being spread. The use of a copper / molybdenum film or molybdenum / copper / molybdenum triple film results in better adhesion to the upper photoresist (PR) and the lower glass, and also provides fluorine ions over the copper titanium film. It can be used less and has the advantage of less glass damage (glass damage).

Korean Patent Publication No. 10-1999-017836 discloses an etching solution in which phosphoric acid, nitric acid, and acetic acid are mixed as an etching solution of a copper / molybdenum film. Korean Patent Publication No. 10-2000-0032999 discloses an etching solution in which iron (III) chloride hexahydrate and hydrofluoric acid are mixed as an etching solution for a copper film. However, when etching the copper / molybdenum film using these etching solutions, the etching speed is too fast, which causes a problem in the process margin, and the taper angle of the taper profile is 90 ° or larger. This makes the subsequent process difficult and the pattern linearity is poor. In addition, in order to etch the copper / molybdenum film is mainly used as a peroxide-based etching solution, such as Korea Patent Publication No. 10-2006-0099089. In general, the peroxide-based etching solution contains a fluoride, causing the glass substrate to etch the panel manufacturing process It has a problem of limiting the reuse of the glass substrate in the event of a failure. In addition, Korean Patent Publication No. 10-2010-0064361 also includes a fluorine-containing acid together with hydrogen peroxide, amino acids, pH stabilizers, acidic pH regulators.

The present invention has been made to solve the problems of the prior art, the object of the present invention is a copper / molybdenum (Cu / Mo) film or molybdenum / copper / molybdenum triple film (Mo / Cu / Mo) Not only is it possible to collectively etch, but there is no residue while eliminating the possibility of defects caused by the etching of the glass substrate by the fluoride, and the etching rate, etching amount and taper angle suitable for the process are appropriate. It is to provide an etching composition.

In order to achieve the above and other objects, the present invention provides an etching composition for a thin film transistor liquid crystal display device comprising a hydrogen peroxide, an etchant, a chelating agent, an ammonium compound, an azole compound and water so that the total weight is 100% by weight. to provide.

More specifically, the etching composition according to the present invention is 5 to 20% by weight of hydrogen peroxide, 0.1 to 5% by weight of the etchant, 0.1 to 5% by weight of chelating agent, 0.1 to 5% by weight of ammonium compound, 0.01 to 2% by weight Free when etching copper / molybdenum film and molybdenum / copper / molybdenum triple layer when water, preferably deionized water, is mixed with the% azole compound and the total weight of the total composition to 100% by weight. There is no damage, and an appropriate etching rate, etching amount and taper tilt angle can be provided.

The hydrogen peroxide used in the present invention serves to oxidize copper to form Cu ²⁺ , and when the content of hydrogen peroxide in the total composition is 20% by weight or more, not only causes a poor etching profile due to excessive oxidation of the metal wiring. If the transition metal content, which is the biggest disadvantage of hydrogen peroxide base, rises to a certain level, it may cause stability problems. On the contrary, in the case of 5% by weight or less, the oxidation power of copper / molybdenum is not etched or it may take a long time to etch and there may be no process margin. Therefore, the appropriate content of hydrogen peroxide is preferably 5 to 20% by weight.

As the etchant used in the present invention, inorganic salts and inorganic acids are used. The inorganic salt may be selected from one or more of the group consisting of potassium hydrogen sulfate, sodium nitrate, ammonium sulfate, sodium sulfate and sodium hydrogen sulfate. The inorganic acid may be sulfuric acid (H ₂ SO ₄ ), phosphoric acid (H ₃ PO ₄ ), nitric acid (HNO ₃ ), or the like. Inorganic salts and inorganic acids replace copper oxide produced by hydrogen peroxide with copper nitrate (Cu (NO ₃ ) ₂ ) and copper sulfate (CuSO ₄ ), wherein the compound produced is water soluble and can be dissolved in the etching composition. The etchant is preferably used in an amount of 0.1 to 5% by weight relative to the total weight of the total composition. When the etchant is used in an amount of 0.1 wt% or less, the etching ability is not exerted, and when the etchant is used in an amount of 5 wt% or more, the etching is too fast and difficult to control. Although the etchant does not have a big problem in etching even when used as a single component, it may be used by mixing two or more kinds for fine control of the profile and taper inclination angle.

The chelating agent used in the present invention is characterized by being an organic chelating agent containing an amino group and a carboxyl group. The organic chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), iminodiacetic acid, nitrilotriacetic acid, and diethylene trinitrilo pentaacetic acid (DTPA). These may be used alone or in the form of a mixture of two or more thereof. The chelating agent prevents a phenomenon that the etching ability decreases due to an increase in copper or metal ions in the etching solution when the number of etching treatments of the metal wiring to be etched increases. In addition, when the etching solution is stored in the present invention using hydrogen peroxide together, hydrogen peroxide may be prevented from self-decomposing to lower the etching ability. The chelating agent is preferably included in an amount of 0.1 to 5% by weight relative to the total weight of the total composition. When the amount of chelate used exceeds 5% by weight, the critical point which is no longer influential is reached. Also, the solubility may be poor due to poor solubility. It does not prevent the etching ability from falling.

The ammonium compound used in the present invention is characterized in that the organic ammonium, inorganic ammonium including an ammonium group. The ammonium compound dissociates in water and penetrates into the photoresist denatured in ionic form to remove the dopant ions penetrated during the dry etching process in the photoresist. In addition, when copper is used as the main wiring metal film and copper / molybdenum film or molybdenum / copper / molybdenum triple film having excellent adhesion to glass film and silicon film is generally used, it is etched unless it contains fluoride. This causes the problem that residues are generated on the surface. The ammonium compound helps to etch the lower molybdenum by adjusting the pH of the etchant to etch without residue without using fluoride. At this time, the most important thing to remove the residue is pH, the pH can be etched without the residue is about 1.0 ~ 3.5. If the ammonium compound is less than 0.1% by weight, the residue of the metal film may not be completely solved, and thus the wiring of the metal film may not be uniformly formed. However, in the case of more than 5% by weight, an undercut of the lower molybdenum is caused in the copper / molybdenum film due to the increase in pH, and in the upper and the lower part in the molybdenum / copper / molybdenum triple film. Undercuts can be triggered and can cause stability problems during the treatment process due to rapid pH rises.

The ammonium compound is applicable to water-soluble compounds having an ammonium group, such as ammonium acetate, ammonium nitrate, ammonium citrate, ammonium persulfate, ammonium chloride, tetramethyl ammonium hydroxide, ammonia water, etc., for precise pH control Two or more kinds can be used in combination.

An azole compound may be used as a material for controlling etching used in the present invention. The azole compound is preferably added in an amount of 0.01 to 2% by weight based on the total weight of the total composition, and may be used for controlling the etching rate and etching amount of copper or copper alloy. As examples of these azole compounds, 5-aminotetrazole, 1,2,3-benzotriazole, methylbenzotriazole, imidazole and the like can be mentioned. If such an etchant is contained in an amount of less than 0.01% by weight, the loss due to etching (CD, Critical Dimension) may be large, and if it contains more than 2% by weight, the etching rate of copper or copper alloy may be slowed. Not only can the taper bevel angle become uneven. In the present invention, the remaining amount of the total composition may be mixed with water, and may serve to dilute the etching composition.

When the etching process is performed with the etching composition according to the present invention, the loss due to etching is 1.0 μm or less, the tapered inclination angle is 30 ° to 60 °, and residues of the lower molybdenum do not occur, thereby enabling effective etching.

The etching composition according to the present invention is a copper / mol which is a main wiring material of a gate electrode and a source / drain that constitutes a thin film transistor liquid crystal display (TFT-LCD). It can be used for the patterning of the ribbed film and molybdenum / copper / molybdenum triple film.

Meanwhile, the term “copper / molybdenum film” used in the present invention refers to a double film in which a copper film and a molybdenum film are sequentially stacked, for example, as shown in FIG. It is to be understood that "denium / copper / molybdenum film" means a triple film of a form in which a molybdenum film, a copper film and a molybdenum film are sequentially stacked as shown in FIG. 4, for example.

According to the etching composition according to the present invention, not only can the copper / molybdenum film and the molybdenum / copper / molybdenum triple film be uniformly etched, but also contain no fluoride, so that the glass substrate is not etched and the process is defective. When generated, the glass substrate can be reused, thereby minimizing material loss.

FIG. 1 is a photograph of observing a profile of a copper / molybdenum film (FIG. 1A) and a molybdenum / copper / molybdenum triple film (FIG. 1B) after etching with an etching composition according to Example 1 of the present invention. FIG.
2 is a photoresist (PR, Photo resist) of the copper / molybdenum film (Fig. 2a), molybdenum / copper / molybdenum triple layer (Fig. 2b) after the etching process with an etching composition according to Example 1 After the strip, the glass film is observed with an electron microscope.
3 is a diagram illustrating one example of a copper / molybdenum double film.
4 is a diagram illustrating one example of molybdenum / copper / molybdenum triple film.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only for illustrating the present invention, and the present invention is not limited to the following examples. The weight percent in the following examples are intended to more clearly indicate the relative amount, and those skilled in the art will be able to repeatedly reproduce the experiment by appropriately adjusting the scale in the amount of the weight percent given below. will be.

Example 1

15% by weight of hydrogen peroxide, 1% by weight of potassium hydrogen sulfate as an etchant, 1% by weight of sulfuric acid, 1% by weight of iminodiacetic acid as a chelating agent, 3% by weight of tetramethyl ammonium hydroxide as an ammonium compound, 5- as an azole compound An etching composition was prepared by mixing 0.2% by weight of aminotetrazole and up to 100% by weight of water (see Table 1).

[Examples 2 to 4]

An etching composition was prepared in the same manner as in Example 1, except for changing the components and contents of the etching composition as shown in Table 1 below.

[Comparative Examples 1 to 4]

Performed in the same manner as in Example 1, but was mixed to the ingredients and contents shown in Table 2 to prepare an etching composition.

[Examples 5 to 8]

Etch compositions were prepared in the same manner using other compounds not used in Examples 1-4. Components and contents of the etching composition used at this time are shown in Table 3 below.

[Comparative Examples 5 to 8]

To carry out the same as in Example 5, it was prepared by mixing in the ingredients and contents shown in Table 4.

[Test Example]

Etching process

Using the etching compositions of Examples 1 to 8 and Comparative Examples 1 to 8 prepared above, the etching process was performed on the copper / molybdenum film and the molybdenum / copper / molybdenum triple layer at a temperature of 30 ° C., respectively. . Next, a method of manufacturing a liquid crystal display device using the etching solution according to the present invention for forming a gate wiring, a gate electrode, a data wiring, and a source / drain electrode will be described.

After depositing a first molybdenum / copper / molybdenum triple layer on the substrate, a first photoresist pattern is formed on the molybdenum / copper / molybdenum triple layer by a photolithography process. Next, the first molybdenum / copper / molybdenum triple layer is formed using a first photoresist pattern as a mask, and a gate line having one direction and a gate electrode protruding from the gate line are formed. A gate insulating film is deposited on it. Thereafter, a semiconductor layer is deposited on the entire surface including the gate insulating layer, and then a predetermined region is patterned to form an active layer.

Next, after depositing a second copper / molybdenum film on the entire surface of the substrate, a second photoresist film pattern is formed on the second copper / molybdenum film by a photolithography process, and the second copper / mol is used as an etching solution according to the present invention. The metal layer is etched to form a pixel region by vertically crossing the gate line to form a pixel area, a source electrode protruding from one side of the data line, and a drain electrode spaced apart from the source electrode by a predetermined distance.

In the etching process, the physical properties of the glass substrate were exceeded by 100% from the end point detection (EPD, End Point Detect). At this time, the reason for the excess etching exceeding 100% is that the etching rate of molybdenum is relatively slow compared to the copper film so that the tail and residue of molybdenum can be sufficiently removed.

Property evaluation

In Examples 1 to 8 and Comparative Examples 1 to 8, the etching loss and the inclination angle were shown in Tables 1, 2, 3, and 4 by the following methods. The etching loss was evaluated as "excellent" when the thickness was 0.5 µm ± 0.2 µm or less, "excellent" when the inclination angle was 30 degrees or more and 70 degrees or less, and "excellent" that no residue of the metal film was found.

1 is an etching composition according to Example 1 of the present invention after etching the copper / molybdenum film (Fig. 1a), molybdenum / copper / molybdenum triple layer (Fig. 1b) the profile (Electronic) It is a photograph observed under a microscope.

FIG. 2 is an etching composition according to Example 1, after etching the copper / molybdenum film (Fig. 2a) and molybdenum / copper / molybdenum triple layer (Fig. 2b) strips the photoresist (PR, Photoresist) (Strip) It is a photograph observed with the electron microscope, and the tail and the residue of a molybdenum film are not seen.

[Etch Loss Measurement]

The profile of the copper / molybdenum film and molybdenum / copper / molybdenum triple layer etched by the etching method was observed using an electron microscope (SEM, Hitachi S-4700) and the photo. The distance between the end of the resist and the end of the copper film was measured and represented by an etch loss measurement.

[Inclination angle measurement]

Profiles etched by the etching process were observed using an electron microscope (SEM, Hitachi, S-4700) and the inclination angles were measured by measuring the value of the inclination angle of the etched side.

[ Residue measurement ]

The copper / molybdenum film and the molybdenum / copper / molybdenum triple layer etched through the etching process were removed using a PR (photoresist) stripper, followed by (Profile) using an electron microscope (SEM). , Hitachi, S-4700) was used to observe the wiring surface and represent residue.

Claims (10)

An etching composition for a thin film transistor liquid crystal display device which simultaneously etches copper and molybdenum in a copper / molybdenum double layer or a molybdenum / copper / molybdenum triple layer.
Hydrogen peroxide;
Etching agents consisting of mixtures of inorganic salts and inorganic acids;
Chelating agents;
Ammonium compounds including any one of ammonium citrate, tetramethyl ammonium hydroxide or compounds thereof; And
An azole compound;
PH of the etching composition is 1.0 to 3.5,
The inorganic salt is any one or two or more selected from the group consisting of potassium hydrogen sulfate and sodium hydrogen sulfate, and the inorganic acid is any one or two or more selected from the group consisting of sulfuric acid and nitric acid. The method of claim 1,
5-20 wt% hydrogen peroxide, 0.1-5 wt% etchant, 0.1-5 wt% chelating agent, 0.1-5 wt% ammonium compound, 0.01-2 wt% azole compound and total gross weight of the composition Etching composition for a thin film transistor liquid crystal display comprising water so that the weight is 100% by weight. delete delete delete 3. The method according to claim 1 or 2,
The chelating agent is one or a mixture of two or more selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), imino diacetic acid, nitrilotriacetic acid and diethylene trinitrilo pentaacetic acid (DTPA) Etching composition for a thin film transistor liquid crystal display device. delete 3. The method according to claim 1 or 2,
The azole compound is one or a mixture of two or more selected from the group consisting of 5-aminotetrazole, 1,2,3-benzotriazole, methylbenzotriazole and imidazoline azole compound Etching composition for thin film transistor liquid crystal display device. delete delete

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