KR20190094842A - Etchant composition for etching metal layer and method of forming conductive pattern using the same - Google Patents

Abstract

According to embodiments of the present invention, provided is a metal film etchant composition which, with respect to the total weight of the composition, comprises: 62-68 wt% of phosphoric acid; 6-8 wt% of nitric acid; 4-6 wt% of acetic acid; 0.2-1.0 wt% of acetate; 0.1-0.3 wt% of phosphorous acid; and the remainder consisting of water. The metal film etchant composition is used to form a conductive pattern having a fine size, wherein an etching failure is reduced.

Description

Metal film etching solution composition and conductive pattern forming method using the same {ETCHANT COMPOSITION FOR ETCHING METAL LAYER AND METHOD OF FORMING CONDUCTIVE PATTERN USING THE SAME}

The present invention relates to a metal film etching liquid composition and a conductive pattern forming method using the same. More specifically, the present invention relates to a metal film etching liquid composition containing an acid component and a method of forming a conductive pattern using the same.

For example, thin film transistors (TFTs) have been utilized as part of driving circuits for semiconductor devices and display devices. The TFT is arranged for each pixel on, for example, a substrate of an organic light emitting display (OLED) device or a liquid crystal display (LCD), and includes wirings of a pixel electrode, an opposite electrode, a source electrode, a drain electrode, a data line, a power line, and the like. Can be electrically connected to the TFT.

In order to form the electrode or the wiring, a metal film may be formed on the display substrate, a photoresist is formed on the metal film, and then the metal film may be partially removed using an etchant composition.

In order to reduce wiring resistance to prevent signal transmission delay and to secure chemical resistance and stability of the wiring, the metal film may be formed of a multi-layered film including heterogeneous metals having different chemical characteristics or heterogeneous conductive materials.

For example, a silver-containing film may be formed to implement low resistance characteristics, and a transparent conductive oxide film such as indium tin oxide (ITO) may be further formed to improve chemical resistance, stability, and permeability. .

In the etchant composition, inorganic-based strong acids such as phosphoric acid and sulfuric acid are used as the base component, as disclosed in Korean Patent Publication No. 10-0579421. However, when using the conventional etchant composition there was a problem that metal resorption or residue and surface stains occur.

Korea Patent Publication No. 10-0579421 (2006.05.08.)

One object of the present invention is to provide a metal film etching liquid composition which can solve problems such as residue and surface staining while having improved etching uniformity.

One object of the present invention is to provide a conductive pattern forming method using the metal film etchant composition.

One object of the present invention is to provide a method of manufacturing a display substrate using the metal film etchant composition.

1. 62-68 weight percent phosphoric acid in the total weight of the composition; Nitric acid 6-8 wt%; Acetic acid 4-6% by weight; 0.2 to 1.0 wt% acetate; 0.1 to 0.3% by weight phosphorous acid; And excess water.

2. The metal film of claim 1, wherein the acetate salt comprises at least one selected from the group consisting of sodium acetate, ammonium acetate, potassium acetate, and calcium acetate. Etch solution composition.

3. forming a metal film on the substrate; And etching the metal film using the metal film etching solution composition of 1 or 2 above.

4. In the above 3, wherein the forming the metal film comprises the step of forming a silver containing film, conductive pattern forming method.

5. The method of 4 above, wherein the forming of the metal film further comprises forming a transparent conductive oxide film, the conductive pattern forming method.

6. In the above 5, wherein the transparent conductive oxide film comprises a first transparent conductive oxide film and a second transparent conductive oxide film formed between the silver containing film, conductive pattern forming method.

7. In the above 5, the transparent conductive oxide film is composed of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), gallium zinc oxide (GZO) and indium gallium zinc oxide (IGZO). And at least one selected from the group.

8. The method of claim 3, further comprising: forming a thin film transistor on the substrate; Forming a pixel electrode electrically connected to the thin film transistor; And forming a display layer on the pixel electrode, wherein the metal film is formed on the display layer.

9. In the above 3, wherein the conductive pattern is provided as a common electrode, a reflective electrode or a wiring of the image display device, the conductive pattern forming method.

According to the exemplary embodiments of the present invention described above, acetate and phosphorous acid prevent the occurrence of residues and stains in the wet etching process, so that the occurrence of wiring shorts or dark spots (dark spots, blind spots) due to the residues can be suppressed. have.

In addition, when the metal film includes a silver containing film and a transparent conductive oxide film, the etching initiator may initiate a metal oxide substitution reaction, so that the silver containing film and the transparent conductive oxide film may be uniformly etched together.

By using the etchant composition, for example, an electrode or a wire, such as a reflective electrode of a display device, a sensing electrode, a trace, or a pad of a touch sensor may be formed to have a desired aspect ratio and profile.

1 and 2 are cross-sectional views illustrating a method of forming a conductive pattern in accordance with example embodiments.
3 is a cross-sectional view illustrating a method of manufacturing a display substrate in accordance with example embodiments.
4 to 9 are electron microscope images of batch etching of Examples 1 to 6, respectively.
10 to 18 are electron microscope images of batch etching of Comparative Examples 1 to 9, respectively.
19 to 24 are photographs obtained by evaluating the residues or stains of Examples 1 to 6, respectively.
25 to 33 are photographs obtained by evaluating the residues or stains of Comparative Examples 1 to 9, respectively.

According to embodiments of the present invention, there is provided a metal film etchant composition (hereinafter, abbreviated as "etchant composition") comprising phosphoric acid, nitric acid, acetic acid, acetate, phosphorous acid and excess water. In addition, a method of forming a conductive pattern and a method of manufacturing a display substrate using the metal film etchant composition is provided.

The term "metal film" used in the present application is used as a term encompassing a metal single film and a laminated structure of the metal single film and the transparent conductive oxide film. In addition, the metal film may include a plurality of metal single films formed of different kinds of metals.

In example embodiments, the metal layer may include a silver containing layer. The silver-containing film may refer to a film including silver or silver alloy. In addition, the silver-containing film may include a multilayer structure of two or more layers.

For example, the silver alloy is neodynium (Nd), copper (Cu), palladium (Pd), niobium (Nb), nickel (Ni), molybdenum (Mo), chromium (Cr), magnesium (Mg), tungsten (W), protactinium (Pa), titanium (Ti) or a combination of two or more thereof, and an alloy of silver (Ag); Silver compounds containing dopant elements such as nitrogen (N), silicon (Si), and carbon (C); Or combinations of two or more thereof.

The transparent conductive oxide film may include a transparent metal oxide. For example, the transparent metal oxide may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), gallium zinc oxide (GZO), indium gallium zinc oxide (IGZO), or a combination thereof. It may include.

Hereinafter, embodiments of the present invention will be described in detail, and a case in which the metal film includes a silver containing film and a transparent conductive oxide film will be described as an example. However, this corresponds to preferred examples, and the spirit and scope of the present invention are not necessarily limited thereto.

<Etching solution composition>

The phosphoric acid included in the etchant composition according to the embodiments of the present invention may serve as a main oxidant. For example, the phosphoric acid may serve as an oxidizer for the silver-containing film and the transparent conductive oxide film.

In some embodiments, the phosphoric acid may be included in an amount of about 62 to 68 weight percent, preferably 64 to 66 weight percent of the total weight of the composition. When the content of phosphoric acid is less than about 62% by weight, the etching rate of the metal film may be inhibited and the etching rate of the silver-containing film may be inhibited and the etching profile may be poor. When the content of the phosphoric acid is greater than about 68% by weight, the etching speed of the silver-containing film is excessively fast, for example, a tip may occur in the transparent conductive oxide film, and the etching profile may be poor.

The nitric acid may serve as a secondary oxidant. For example, the silver nitrate may serve as an oxidizer for the silver-containing film and the transparent conductive oxide film. As the nitric acid and phosphoric acid work together, the silver-containing film and the transparent conductive oxide film may be uniformly etched together.

In some embodiments, the nitric acid may be included in an amount of about 6 to 8% by weight, preferably 6.5 to 7.5% by weight of the total weight of the composition. When the content of nitric acid is less than about 6% by weight, the etching rate of silver and the transparent conductive oxide film may be lowered, the etching profile may be poor, and staining may be severe. When the content of nitric acid is more than 8% by weight, the etching rate of the transparent conductive oxide film is excessively faster, for example, an undercut may occur that the transparent conductive oxide film is shorter than the silver-containing film, and the etching profile may be poor. .

The acetic acid may serve as a secondary oxidant. For example, the acetic acid may reduce the etch loss (CD skew) of the conductive pattern obtained by appropriately promoting or adjusting the etching rate of the silver-containing film, and may promote fine pattern formation.

In some embodiments, the acetic acid may be included in an amount of about 4 to 6 weight percent, preferably 4.5 to 5.5 weight percent of the total weight of the composition. When the content of acetic acid is less than 4% by weight, the etching rate of the substrate may be uneven, so that the etching profile may be lowered, and pattern straightness may be poor. When the content of acetic acid is more than 6% by weight, foaming may occur, which may cause a poor amount of etching and an etching profile, and may cause Ag resorption.

The acetate may serve as an auxiliary oxidant of the metal film, and may suppress generation of metal film residues and stains.

In some embodiments, the acetate salt may be included in an amount of about 0.2 to 1.0 weight percent of the total weight of the composition. When the content of the acetate is less than 0.2% by weight, the effect of preventing the occurrence of metal film residues and stains may be insignificant. When the content of the acetate is greater than 1.0% by weight, the etching rate is lowered and the etching profile may be lowered.

In example embodiments, the acetate salt may include at least one selected from the group consisting of sodium acetate, ammonium acetate, potassium acetate, and calcium acetate. And preferably ammonium acetate may be used.

The phosphorous acid may serve as an auxiliary oxidant of the metal film, and may suppress generation of metal film residues and stains.

In some embodiments, the phosphorous acid may be included in an amount of about 0.1 to 0.3% by weight of the total weight of the composition. When the content of the phosphorous acid is less than 0.1% by weight, metal film residues or stains may occur. When the content of the phosphorous acid is more than 0.3% by weight, the etching rate may be lowered and the etching profile may be poor.

The etchant composition may include excess or residual amount of water except for the above-described components, and may include, for example, deionized water. In the case of the deionized water, for example, it may have a specific resistance value of 18 mA / cm or more.

As used herein, the term "extra or residual amount" means a variable amount including the above-described components and the amount excluding the additive when other additives are included.

In some embodiments, the additive may be included to improve the etching efficiency or the etching uniformity within a range that does not inhibit the action of the above-described components. For example, the additive may include an agent for preventing corrosion, preventing etching byproduct adsorption, adjusting the taper angle of an etching pattern, and the like widely used in the art.

<Conductive Pattern Formation Method>

1 and 2 are schematic cross-sectional views for describing a wire forming method according to example embodiments.

Referring to FIG. 1, a lower conductive pattern 115 and a lower insulating layer 110 may be formed on the substrate 100.

The substrate 100 may include a glass substrate, a polymer resin or plastic substrate, an inorganic insulating substrate, or the like.

The lower conductive pattern 115 may include, for example, a transparent conductive oxide such as aluminum (Al), copper (Cu), molybdenum (Mo), tungsten (W), titanium (Ti), tantalum (Ta), or ITO. It can be formed to. The lower insulating layer 110 may be formed to include an organic insulating material such as an acrylic resin, polysiloxane, and / or an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like.

The lower conductive pattern 115 may be provided as a conductive via or a conductive contact, for example.

In example embodiments, the first transparent conductive oxide layer 121, the silver containing layer 123, and the second transparent conductive oxide layer 125 may be sequentially stacked on the lower insulating layer 110 and the lower conductive pattern 115. The metal film 120 may be formed.

The first and second transparent conductive oxide layers 121 and 125 may be formed to include a transparent metal oxide such as ITO, IZO, GZO, IGZO, or the like. The silver containing film 123 may be formed to include silver and / or a silver alloy as described above. The first transparent conductive oxide film 121, the silver containing film 123, and the second transparent conductive oxide film 125 may be formed through, for example, a deposition process such as a sputtering process.

The mask pattern 130 may be formed on the metal layer 120. For example, after forming a photoresist film on the second transparent conductive oxide film 125, the mask pattern 130 may be formed by partially removing the photoresist film through an exposure and development process.

Referring to FIG. 2, the conductive layer 120a may be formed by etching the metal layer 120 using the metal layer etchant composition according to the exemplary embodiments described above. The conductive pattern 120a may include, for example, a first transparent conductive oxide film pattern 122, a silver containing pattern 124, and a first transparent conductive oxide film pattern 126 sequentially stacked on the lower insulating film 110. Can be.

The conductive pattern 120a may be utilized as, for example, a pad, an electrode, or a wiring of the image display device. By forming a relatively silver-containing pattern 124 having excellent low resistance and signal transmission characteristics between the first and second transparent conductive oxide film patterns 122 and 126 having excellent corrosion resistance, low resistance and mechanical and chemical reliability are improved. An improved conductive pattern can be implemented.

In addition, by using the above-described etching initiator, inorganic acid, organic acid, polyhydric alcohol-based profile improver, metal salt, and the like, the phosphoric acid-excluded or reduced etching solution composition, over-etching of the silver-containing pattern 124 is prevented, substantially As a result, a conductive pattern 120a having a uniform and continuous sidewall profile may be formed.

In some embodiments, the thickness of the silver-containing film 123 or the silver-containing pattern 124 may be about 800 GPa or more, and in some embodiments, about 1000 GPa or more. The thicknesses of the first and second transparent conductive oxide layer patterns 122 and 126 may be about 50 to about 100 mm 3.

As the thickness of the silver-containing pattern 124 is increased and the aspect ratio of the conductive pattern 120a is increased in order to implement low resistance, silver residue and etch failure due to overetching may be caused. However, a wet etching process in which the etching failure is suppressed may be implemented using the etchant composition according to the exemplary embodiments.

3 is a cross-sectional view illustrating a method of manufacturing a display substrate in accordance with example embodiments. For example, FIG. 3 illustrates a display substrate including wirings and electrode structures formed by the above-described conductive pattern forming method.

Referring to FIG. 3, a thin film transistor TFT may be formed on the substrate 200. For example, the TFT may include an active layer 210, a gate insulating layer 220, and a gate electrode 225.

In example embodiments, after the active layer 210 is formed on the substrate 200, the gate insulating layer 220 covering the active layer 210 may be formed.

The active layer 210 may be formed to include polysilicon or an oxide semiconductor such as, for example, indium gallium zinc oxide (IGZO). The gate insulating layer 220 may be formed to include silicon oxide, silicon nitride, and / or silicon oxynitride.

The gate electrode 225 may be formed on the gate insulating layer 220 to overlap the active layer 210. The gate electrode 225 may be formed to include a metal such as Al, Ti, Cu, W, Ta, Ag, or the like.

After forming the interlayer insulating film 230 covering the gate electrode 225 on the gate insulating film 220, the source electrode 233 penetrates the interlayer insulating film 230 and the gate insulating film 220 to contact the active layer 210. ) And the drain electrode 237 may be formed. The source electrode 233 and the drain electrode 237 may be formed to include a metal such as Al, Ti, Cu, W, Ta, Ag, or the like.

The via insulating layer 240 may be formed on the interlayer insulating layer 230 to cover the source electrode 233 and the drain electrode 237. The via insulating layer 240 may be formed using an organic insulating material such as an acrylic resin or a siloxane resin.

The pixel electrode 245 electrically connected to the drain electrode 237 may be formed on the via insulating layer 240. The pixel electrode 245 may include a via portion penetrating the via insulating layer 240 to contact the drain electrode 237. The pixel electrode 245 may be formed to include a metal and / or a transparent conductive oxide such as Al, Ti, Cu, W, Ta, Ag, or the like.

The pixel defining layer 250 may be formed on the via insulating layer 240, and the display layer 255 may be formed on the upper surface of the pixel defining layer 250 exposed by the pixel defining layer 250. The display layer 255 may be formed of, for example, an organic light emitting layer (EML) included in an OLED device or a liquid crystal layer included in an LCD device.

The opposite electrode 260 may be formed on the pixel defining layer 250 and the display layer 255. The opposite electrode 260 may be provided as a common electrode, a reflective electrode, or a cathode of the image display device.

In example embodiments, the counter electrode 260 may be formed by sequentially stacking a first transparent conductive oxide film, a silver-containing film, and a second transparent conductive oxide film, and then patterning the same through a wet etching process using the above-described etching solution composition. Can be.

Accordingly, the counter electrode 260 may include the first transparent conductive oxide pattern 262, the silver containing pattern 124, and the second transparent conductive oxide pattern that are sequentially stacked on the pixel defining layer 250 and the display layer 255. (266).

In some embodiments, the image display device may include a display area I and a non-display area II. The TFT, the pixel electrode 245, the display layer 255, and the counter electrode 260 may be formed on the display area I. The wiring 270 may be formed on the non-display area II. The wiring 270 may be electrically connected to the TFT or the counter electrode 260.

The wiring 270 also includes, for example, a first transparent conductive oxide film pattern 272, a silver containing pattern 274, and a second transparent conductive oxide film pattern 276 sequentially stacked on the via insulation layer 240. It may be patterned using an etchant composition according to exemplary embodiments.

In an embodiment, the wirings 270 may be formed together through a wet etching process that is substantially the same as the counter electrode 260 on the display area I.

As described above, since the counter electrode 260 and / or the wiring 270 of the image display apparatus are formed in a laminated structure including the first transparent conductive oxide film pattern-silver containing pattern-second transparent conductive oxide film pattern, While implementing the resistance properties, the mechanical / chemical stability and the optical properties can be improved together. In addition, as the above-described etching solution composition is used, defects such as silver residue, side damage, tip development, and the like can be suppressed.

In some embodiments, the gate electrode 225, the source electrode 233, the drain electrode 237, and the pixel electrode 245 may be patterned by using the etching solution composition or the conductive pattern forming method described above.

In addition, the above-described etching liquid composition may be used to form various conductive patterns of the touch sensor included in the image display device in which the display substrate is employed. For example, sensing electrodes, traces, pads, etc. of the touch sensor may be formed using the etchant composition.

Hereinafter, experimental examples including specific examples and comparative examples are provided to help understanding of the present invention, but these are merely illustrative of the present invention and are not intended to limit the scope of the appended claims. It is apparent to those skilled in the art that various changes and modifications to the embodiments can be made within the spirit and scope, and such variations and modifications are within the scope of the appended claims.

Examples and Comparative Examples

To the components and contents (% by weight) described in Table 1 according to Examples and Comparative Examples

A metal film etchant composition was prepared.

Phosphoric Acid nitric acid Acetic acid Acetate
(Ammonium acetate) Phosphorous acid water Example 1 65 7 5 0.2 0.2 Remaining amount Example 2 65 7 5 1.0 0.2 Remaining amount Example 3 65 7 5 0.2 0.1 Remaining amount Example 4 65 7 5 1.0 0.3 Remaining amount Example 5 64 6.5 4.5 0.2 0.2 Remaining amount Example 6 66 7.5 5.5 0.2 0.2 Remaining amount Comparative Example 1 65 7 5 0 0 Remaining amount Comparative Example 2 65 7 5 0.2 0 Remaining amount Comparative Example 3 65 7 5 0 0.2 Remaining amount Comparative Example 4 60 7 5 1.0 0.3 Remaining amount Comparative Example 5 70 7 5 1.0 0.3 Remaining amount Comparative Example 6 65 5 5 0.2 0.2 Remaining amount Comparative Example 7 65 10 5 0.2 0.2 Remaining amount Comparative Example 8 65 7 3 0.2 0.2 Remaining amount Comparative Example 9 65 7 10 0.2 0.2 Remaining amount

Experimental Example

An ITO (100 mm 3) / Ag (1000 mm 3) / ITO (100 mm) triple film was formed on a glass substrate, and a sample cut into a size of 10 cm × 10 cm was prepared using a diamond knife.

Metal film etching liquid compositions of Examples and Comparative Examples were injected into a spray etching equipment (ETCHER, manufactured by K.C.Tech). After the temperature of the metal film etchant composition was set to 40 ° C., when the temperature reached 40 ± 0.1 ° C., the metal film etchant composition was sprayed onto the sample to perform an etching process for 85 seconds.

After the etching process was finished, the sample was washed with deionized water, dried using a hot air dryer, and the photoresist was removed using a photoresist stripper.

(1) batch etching evaluation

The etched sample was visually determined using an electron scanning microscope (SU-8010, manufactured by HITACHI Co., Ltd.) and visually etched, and the results are shown in Table 2 below. In addition, the micrographs of Examples 1 to 6 and Comparative Examples 1 to 9 are shown in Figs. 4 to 18, respectively.

○: batch etching

X: bulk food

(2) spot observation

The etched sample was visually observed to determine whether the sample surface was stained, which is shown in FIGS. 19 to 33. In the drawing (photo), the spot where the stain is generated is indicated by a thick dotted line circle.

division Batch etching Presence of stain Example 1 ○ radish Example 2 ○ radish Example 3 ○ radish Example 4 ○ radish Example 5 ○ radish Example 6 ○ radish Comparative Example 1 ○ U Comparative Example 2 ○ U Comparative Example 3 ○ U Comparative Example 4 × radish Comparative Example 5 Pattern out radish Comparative Example 6 × radish Comparative Example 7 × radish Comparative Example 8 × radish Comparative Example 9 × radish

Referring to Table 2 and the drawings, the etchant composition of the embodiment including the component according to the exemplary embodiments is capable of batch etching of the ITO / Ag / ITO triple layer, the staining was suppressed.

On the other hand, in the case of the etching liquid composition of Comparative Examples 1 to 3 containing no acetate and phosphorous acid, the batch etching ability was good, but staining occurred.

In the etching solution compositions of Comparative Examples 4, 6, and 8 each containing phosphoric acid, nitric acid, and acetic acid, the stain was not observed, but batch etching was impossible.

In the etching solution composition of Comparative Example 5 containing too much phosphoric acid, stains were not visually observed, but due to excessive etching rate, all metals were etched and the pattern was lost (Pattern Out).

In the case of the etchant composition of Comparative Examples 7, 9, each containing excessive nitric acid and acetic acid, no stain was observed, but batch etching was impossible.

100, 200: substrate 110: lower insulating film
115: lower conductive pattern 120: metal film
120a: conductive pattern 121: first transparent conductive oxide film
122, 262, and 272: first transparent conductive oxide film pattern
123: silver containing film 124, 264, 274: silver containing pattern
125: second transparent conductive oxide film
126, 266, and 276: second transparent conductive oxide film pattern
210: active layer 210: gate electrode
233: source electrode 237: drain electrode
245: pixel electrode 260: counter electrode
270: wiring

Claims (9)

Of the total weight of the composition,
62 to 68 weight percent phosphoric acid;
Nitric acid 6-8 wt%;
Acetic acid 4-6% by weight;
0.2 to 1.0 wt% acetate;
0.1 to 0.3% by weight phosphorous acid; And
Metallic film etchant composition comprising excess water. The metal film etchant composition of claim 1, wherein the acetate salt comprises at least one selected from the group consisting of sodium acetate, ammonium acetate, potassium acetate, and calcium acetate. . Forming a metal film on the substrate; And
And etching the metal film using the metal film etching solution composition of claim 1 or 2. The method of claim 3, wherein forming the metal film comprises forming a silver containing film. The method of claim 4, wherein the forming of the metal film further includes forming a transparent conductive oxide film. The conductive pattern forming method according to claim 5, wherein the transparent conductive oxide film includes a first transparent conductive oxide film and a second transparent conductive oxide film formed with the silver containing film therebetween. The method of claim 5, wherein the transparent conductive oxide film is in the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), gallium zinc oxide (GZO) and indium gallium zinc oxide (IGZO). And at least one selected. The method according to claim 3,
Forming a thin film transistor on the substrate;
Forming a pixel electrode electrically connected to the thin film transistor; And
Forming a display layer on the pixel electrode;
And the metal film is formed on the display layer. The method of claim 3, wherein the conductive pattern is provided as a common electrode, a reflective electrode, or a wiring of an image display device.

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