KR102583609B1 - Etching solution composition for copper-based metal layer, manufacturing method of an array substrate for crystal display using the same - Google Patents

Abstract

The present invention relates to an etchant composition for a copper-based metal film containing a certain amount of hydrogen peroxide, an azole-based compound, a water-soluble compound having a nitrogen atom and a carboxyl group in one molecule, a phosphate, acetate, a polyhydric alcohol-type surfactant, and water, and a method using the composition. It relates to a method of manufacturing an array substrate for a display device.

Description

Etching solution composition for copper-based metal film, manufacturing method of array substrate for display device using the same {ETCHING SOLUTION COMPOSITION FOR COPPER-BASED METAL LAYER, MANUFACTURING METHOD OF AN ARRAY SUBSTRATE FOR CRYSTAL DISPLAY USING THE SAME}

The present invention relates to an etchant composition for copper-based metal films and a method of manufacturing an array substrate for a display device using the composition.

The process of forming metal wiring on a substrate in a semiconductor device typically consists of a metal film formation process by sputtering, photoresist application, a photoresist formation process in a selective area by exposure and development, and an etching process, Includes cleaning processes before and after individual unit processes. This etching process refers to a process of leaving a metal film in a selective area using a photoresist as a mask, and typically dry etching using plasma or the like or wet etching using an etchant composition is used.

Conventionally, a metal film in which aluminum or an alloy thereof and another metal is laminated has been used as a wiring material for gate and source/drain electrodes. While aluminum is inexpensive and has low resistance, it has poor chemical resistance and can cause short circuits with other conductive layers due to defects such as hillock in post-processing. In addition, it causes malfunction of the liquid crystal panel, such as formation of an insulating layer due to contact with the oxide layer.

Considering this, multilayer films of copper-based metal films such as copper-based metal films and molybdenum films, copper films and molybdenum alloy films, and copper alloy films and molybdenum alloy films have been proposed as wiring materials for gate and source/drain electrodes (Republic of Korea) Publication Patent No. 10-2007-0055259).

However, in order to etch such a multilayer of copper-based metal films, two different types of etchants must be used to etch each metal film. Otherwise, there is a problem of defective etch profiles and residues.

In addition, it was difficult to prevent damage to the metal oxide film to be protected in addition to the film to be etched.

Republic of Korea Patent Publication No. 10-2007-0055259

The present invention was devised to solve the problems of the prior art,

When etching a copper-based metal film, the purpose is to provide an etchant composition that has excellent etching performance for the copper-based metal film to be etched, but does not attack the underlying metal oxide film to be protected.

Another object of the present invention is to provide an etchant composition for copper-based metal films that has excellent etch profile and etch straightness, and does not generate metal film residues.

Another object of the present invention is to provide a method of manufacturing an array substrate for a display device using the etchant composition.

This invention

Based on the total weight of the composition, (A) 5 to 25% by weight of hydrogen peroxide, (B) 0.1 to 5% by weight of an azole compound, (C) 0.1 to 5% by weight of a water-soluble compound having a nitrogen atom and a carboxyl group in one molecule, (D) ) 0.1 to 5% by weight of phosphate, (E) 0.1 to 5% by weight of acetate, (F) 0.01 to 5% by weight of polyhydric alcohol-type surfactant, and (G) the remaining amount of water. A composition is provided.

In addition, the present invention

a) forming gate wiring on the substrate;

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 source and drain electrodes on the semiconductor layer; and

e) forming a pixel electrode connected to the drain electrode; In the method of manufacturing an array substrate for a display device comprising:

Step a) includes forming a copper-based metal film on a substrate, etching the copper-based metal film with the etchant composition for a copper-based metal film of the present invention to form a gate wiring,

The step d) includes forming a copper-based metal film on the semiconductor layer and etching the copper-based metal film with the etchant composition for a copper-based metal film of the present invention to form source and drain electrodes. Provides a method for manufacturing an array substrate.

When etching a copper-based metal film with the etchant composition of the present invention, the etch profile and etch straightness are excellent without causing attack on the underlying metal oxide film to be protected, and the effect of not generating etch residues can be provided.

Figure 1 is a photograph showing that there is no metal residue on the substrate after etching the Cu/MoNb film using the etchant composition of Example 1.
Figure 2 is a photograph showing that metal residue is generated on the substrate when etching the Cu/MoNb film using the etchant composition of Comparative Example 1.

The present invention relates to an etchant composition for copper-based metal films and a method of manufacturing an array substrate for a display device using the same.

The etchant composition of the present invention contains a certain amount of hydrogen peroxide, an azole compound, a water-soluble compound having a nitrogen atom and a carboxyl group in one molecule, a phosphate, acetate, a polyhydric alcohol-type surfactant, and water, so that it can be applied to the lower metal oxide film to be protected. It can provide features such as no attack, excellent etch straightness, excellent etch profile, and no metal etch residue.

The copper-based metal film contains copper (Cu) as a component of the film, and is a concept that includes a single film and a multilayer film of a double film or more. More specifically, the copper-based metal film is a single film of copper or copper alloy (Cu alloy); Alternatively, the concept includes a multilayer film including one or more films selected from the copper film and copper alloy film and one or more films selected from the molybdenum film, molybdenum alloy film, titanium film, and titanium alloy film. Here, the term alloy film refers to a concept that also includes a nitride film or an oxide film.

The copper-based metal film is not particularly limited, but specific examples of the single film include a copper (Cu) film or a copper-based film including aluminum (Al), magnesium (Mg), calcium (Ca), titanium (Ti), and silver (Ag). ), chromium (Cr), manganese (Mn), iron (Fe), zirconium (Zr), niobium (Nb), molybdenum (Mo), palladium (Pd), hafnium (Hf), tantalum (Ta), and tungsten (W). ) and a copper alloy film containing one or more types of metal selected from the like.

Additionally, examples of multilayer films include double films such as copper/molybdenum films, copper/molybdenum alloy films, copper alloy/molybdenum films, and copper alloy/molybdenum alloy films, or triple films of copper/molybdenum/copper films.

In addition, the molybdenum alloy film is, for example, an alloy of molybdenum and one or more metals selected from titanium (Ti), tantalum (Ta), chromium (Cr), nickel (Ni), neodymium (Nd), and indium (In). It means a layer made up of.

Hereinafter, each component constituting the etchant composition of the present invention will be described.

(A) Hydrogen peroxide

Hydrogen peroxide (H ₂ O ₂ ) contained in the etchant composition of the present invention is a component used as the main oxidizing agent, and affects the etching rate of the copper-based metal film (it also affects the etching rate of the alloy film included in the copper-based metal film) ).

The hydrogen peroxide is characterized in that it is contained in an amount of 5 to 25% by weight, and is more preferably contained in an amount of 15 to 23% by weight, based on the total weight of the composition. If the content of hydrogen peroxide is less than 5% by weight, etching may not occur and the etching rate may slow down due to a decrease in the etching power of a single film of a copper-based metal film or a multilayer film composed of the single film and molybdenum or molybdenum alloy film. there is. On the other hand, if it exceeds 25% by weight, the thermal stability may be greatly reduced due to the increase in copper ions, and the overall etching rate may become faster, making it difficult to control the process.

(B) Azole series compound

The azole-based compound included in the etchant composition of the present invention controls the etching speed of the copper-based metal film and reduces CD loss of the pattern, thereby increasing process margins.

The azole-based compound is not particularly limited as long as it is used in the relevant field, and is preferably an azole-based compound having 1 to 30 carbon atoms.

As specific examples, triazole-based, aminotetrazole-based, imidazole-based, indole-based, purine-based, pyrazole-based, pyridine-based , it may be more preferable to include at least one selected from the group consisting of pyrimidine-based, pyrrole-based, pyrrolidine-based, and pyrroline-based compounds.

The azole compound is included in an amount of 0.1 to 5% by weight, and more preferably 0.2 to 1.5% by weight, based on the total weight of the composition. If the content of the azole compound is less than 0.1% by weight, the etching rate of copper is fast and excessively large sid loss may occur. On the other hand, if the content exceeds 5% by weight, the etching speed of copper becomes slow, resulting in a longer process time.

(C) within one molecule nitrogen atom and Water-soluble compounds with carboxyl groups

The water-soluble compound having a nitrogen atom and a carboxyl group in one molecule included in the etchant composition of the present invention serves to prevent etching characteristics from changing when etching a large number of substrates. In addition, it prevents the self-decomposition reaction of hydrogen peroxide that may occur when storing the etchant composition.

In general, in the case of an etchant composition containing hydrogen peroxide, the storage period is shortened due to self-decomposition of hydrogen peroxide during storage, and there is a risk of container explosion. However, when a water-soluble compound having a nitrogen atom and a carboxyl group is included in one molecule, the decomposition rate of hydrogen peroxide is reduced by nearly 10 times, which is advantageous in ensuring storage period and stability. In particular, in the case of the copper layer, if a large amount of copper ions remain in the etchant composition, a passivation film may be formed and the layer may be oxidized to black and then no longer etched. However, this phenomenon can be prevented if the above compound is included.

Specific examples of water-soluble compounds having a nitrogen atom and a carboxyl group in one molecule include alanine, aminobutyric acid, glutamic acid, glycine, iminodiacetic acid, and nitrilotriacetic acid ( nitrilotriacetic acid) and sarcosine, and one or more types selected from these may be used.

The water-soluble compound having a nitrogen atom and a carboxyl group in one molecule is included in an amount of 0.1 to 5% by weight, preferably 1 to 3% by weight, based on the total weight of the composition. Based on the above criteria, if the content is less than 0.1% by weight, a passivation film is formed after etching a large amount of about 500 or more substrates, making it difficult to obtain sufficient process margin. On the other hand, if it exceeds 5% by weight, the etching rate of the metal oxide film slows down, resulting in loss of process time.

(D) Phosphate

Phosphate included in the etchant composition of the present invention is an ingredient that improves the taper profile of the pattern.

The type of the phosphate is not particularly limited, and examples include salts in which one to three hydrogens in phosphoric acid are substituted with alkali metals or alkaline earth metals. More specific examples of the phosphate include sodium phosphate monobasic (NaH ₂ PO ₄ ), sodium phosphate dibasic (Na ₂ HPO ₄ ), sodium phosphate tribasic (Na ₃ PO ₄ ), and potassium phosphate monobasic (KH ₂ PO ₄ ). , potassium dibasic phosphate (K ₂ HPO ₄ ), ammonium monophosphate ((NH ₄ )H ₂ PO ₄ ), ammonium dibasic phosphate ((NH ₄ ) ₂ HPO ₄ ) and ammonium tertiary phosphate ((NH ₄ ). ₃ PO ₄ ), etc., but are not limited thereto, and one or more types selected from these may be used.

The phosphate may be included in an amount of 0.1 to 5% by weight, preferably 1 to 3% by weight, based on the total weight of the etchant composition of the present invention. If the phosphate content is less than 0.1% by weight, a defective etch profile may occur. On the other hand, if the content exceeds 5% by weight, the etching rate decreases and the desired etching rate cannot be achieved, which may result in a decrease in process efficiency, such as a longer process time.

(E) Acetate

Acetate (E) included in the etchant composition of the present invention is an auxiliary oxidizing agent for the metal film and is also an ingredient that prevents residues from being generated.

Examples of the acetate include, but are not limited to, potassium acetate (CH ₃ COOK), sodium acetate (CH ₃ COONa), and ammonium acetate (CH ₃ COONH ₄ ), and one or more types may be selected and used. there is.

The acetate (E) may be included in an amount of 0.1 to 5% by weight, preferably 0.1 to 2% by weight, based on the total weight of the etchant composition of the present invention. If the acetate content is less than 0.1% by weight, there is a risk of etching residues occurring. On the other hand, if the content exceeds 5% by weight, etch profile defects may occur or control of the etch process may be difficult.

(F) Polyhydric alcohol type Surfactants

The polyhydric alcohol-type surfactant included in the etchant composition of the present invention serves to increase the uniformity of etching by reducing surface tension. In addition, by surrounding the copper ions dissolved in the etchant after etching the copper film, the activity of the copper ions is lowered, allowing the process to proceed stably while using the etchant.

Specific examples of the polyhydric alcohol-type surfactant include glycerol, ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol. You can select and use more than one type.

The polyhydric alcohol-type surfactant is included in an amount of 0.01 to 5% by weight, preferably 1 to 3% by weight, based on the total weight of the composition. Based on the above-mentioned standards, if the content is less than 0.01% by weight, the etching uniformity may deteriorate and the decomposition of hydrogen peroxide may accelerate. On the other hand, if it exceeds 5% by weight, there is a disadvantage in that a lot of foam is generated.

(G) water

The water included in the etchant composition of the present invention is not particularly limited, but it is preferable to use deionized water for semiconductor processing, and it is better to use deionized water with a resistivity value of 18 mΩ/cm or more, which shows the degree to which ions have been removed from the water. desirable.

The water is included in the remaining amount so that the total weight of the composition is 100% by weight.

The etchant composition for a copper-based metal film of the present invention may further include one or more additives selected from the group consisting of an etch regulator, a metal ion sequestering agent, a corrosion inhibitor, a pH regulator, and other additives, but are not limited thereto, in addition to the ingredients mentioned above. You can. The additive may be selected from additives commonly used in the field in order to further improve the effect of the present invention within the scope of the present invention.

Each component included in the etchant composition for a copper-based metal film of the present invention preferably has a purity suitable for semiconductor processing, and each component can be manufactured by a commonly known method.

In addition, the present invention

(1) forming a metal oxide film on a substrate;

(2) forming a copper-based metal film on the metal oxide film;

(3) selectively leaving a photoreactive material on the copper-based metal film; and

(4) A method of forming a wire is provided, comprising the step of etching the copper-based metal film using the etchant composition of the present invention.

The metal oxide film is a film capable of forming an oxide semiconductor layer, and a metal oxide film commonly used in the field may be used, for example, AxByCzO (A, B, and C are independently of each other zinc (Zn), titanium ( It is a metal selected from the group consisting of Ti), cadmium (Cd), gallium (Ga), indium (In), tin (Sn), hafnium (Hf), zirconium (Zr), and tantalum (Ta); z represents the ratio of each metal and may be a ternary or quaternary oxide expressed as an integer or decimal number greater than or equal to 0. Specific examples of the metal oxide film include indium oxide film (ITO), indium oxide alloy film, and gallium zinc oxide film (IGZO).

In the etching process using the etchant composition of the present invention, there is no attack on the lower metal oxide film when etching the copper-based metal film in which a metal oxide film is formed on the lower part and the copper-based metal film is formed on the film. That is, in step (4) of the wiring forming method, only the copper-based metal film can be etched, and at this time, no damage occurs to the lower metal oxide film.

In the wiring forming method, the photoreactive material may preferably be a conventional photoresist material, and may be selectively left behind by conventional exposure and development processes.

In addition, the present invention

a) forming gate wiring on the substrate;

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 source and drain electrodes on the semiconductor layer; and

e) forming a pixel electrode connected to the drain electrode; In the method of manufacturing an array substrate for a display device comprising:

Step a) includes forming a copper-based metal film on a substrate and etching the copper-based metal film with the etchant composition of the present invention to form a gate wiring,

Step d) includes forming a copper-based metal film on the semiconductor layer and etching the copper-based metal film with the etchant composition of the present invention to form source and drain electrodes. A manufacturing method is provided.

The above description can be equally applied to the copper-based metal film.

The array substrate for the display device may be a thin film transistor (TFT) array substrate.

Additionally, the present invention provides an array substrate for a display device manufactured by the above manufacturing method.

Hereinafter, the present invention will be described in more detail using examples and comparative examples. However, the following examples and comparative examples are for illustrating the present invention, and the present invention is not limited by the following examples and may be modified and changed in various ways.

< Example and Comparative example > etchant Preparation of composition

6 kg of the etchant compositions of Examples 1 to 7 and Comparative Examples 1 to 8 were prepared according to the ingredients and contents in Table 1 below.

Note) In Table 1 above

ATZ: aminotetrazole

NHP: sodium phosphate monobasic

APM: Ammonium monobasic phosphate

PA: Potassium acetate

AA: ammonium acetate

SA: Sodium acetate

TEG: triethylene glycol

IDA: iminodiacetic acid

< Experiment example > etchant Performance testing of compositions

In the performance test of the etchant compositions of Examples 1 to 7 and Comparative Examples 1 to 8, an IGZO film was deposited as a metal oxide film on a _100mm The deposited thin film substrate was used as a specimen. A photoresist with a predetermined pattern was formed on the substrate through a photolithography process, etched with the composition of Examples 1 to 7 and Comparative Examples 1 to 8, and performance tests were performed as follows.

Experiment example One. etching Profile, straightness and residue evaluation

The etchant compositions of Examples 1 to 7 and Comparative Examples 1 to 8 were placed in a spray-etching experiment equipment (model name: ETCHER (TFT), SEMES), and the temperature of the etchant composition was set to around 30°C and heated. did. The total etching time may vary depending on the etching temperature, but is usually about 110 seconds. Afterwards, it was washed with deionized water and dried using a hot air dryer.

The cross-section of the etching profile of the etched copper-based metal film was measured using a scanning electron microscope (SEM: Hitachi product, model name S-4700).

In addition, residue, which is a phenomenon in which the metal film remains in the area covered with photoresist without being etched, was measured, and the results are listed in Table 2 below.

In addition, the change in one-side etching (㎛) according to the change in Cu ion concentration (300 ~ 5,000 ppm) was measured. Side etch (S/E) refers to the distance between the end of the photoresist on one side and the end of the lower metal measured after etching. If the amount of one-side etching changes, the signal transmission speed changes when driving the TFT and stains may occur, so it is desirable to minimize the amount of change in one-side etching. The amount of change is preferably 0.1 ㎛ or less, and the results are shown in Table 2 below.

<Etching profile and straightness evaluation criteria>

○: Good

△: Normal

Х: bad

Unetch: Unetchable

Experiment example 2. Bottom metal of oxide film damage Occurrence Assessment

Specimens were etched using the etchant compositions of Examples 1 to 7 and Comparative Examples 1 to 8 in the same manner as Experimental Example 1.

At this time, the occurrence of attack on the IGZO film, which is the lower metal oxide film, was confirmed using a scanning electron microscope (SEM: Hitachi product, model name S-4700).

When using the etchant compositions of Examples 1 to 7, no attack occurred on the lower metal oxide film, but when using the etchant compositions of Comparative Examples 3 to 8, damage was caused to the IGZO film, which is the lower metal oxide film. occurred.

<IGZO damage evaluation criteria>

○: Good → IGZO E/R speed (Å/sec) 0 or more ~ less than 1.0

△: Normal → IGZO E/R speed (Å/sec) 1.0 or more ~ less than 2.0

Х: Bad → IGZO E/R speed (Å/sec) 2.0 or more~

As can be seen from the results in Table 2, the etchant compositions of Examples 1 to 7 corresponding to the present invention all showed good etching properties, and no damage occurred to the lower metal oxide film.

In addition, as can be seen in Figure 1, in the case of the copper-based metal film etched with the etchant composition of Example 1, the etch profile and straightness were excellent, and no residue was observed.

On the other hand, in the case of Comparative Example 1 in which hydrogen peroxide was contained below the content range of the present invention, the etching rate of copper was too slow and an unetch phenomenon occurred. In addition, in the case of Comparative Example 2 in which the acetate content was below the content range of the present invention, residues of the molybdenum alloy film were generated, as can be seen in FIG. 2. In the case of Comparative Examples 3 and 4 containing ammonium sulfate, the etching properties were good, but it was confirmed that residues of the metal film were generated.

In the case of Comparative Examples 5 and 6 containing oxalic acid or citric acid, it was confirmed that the amount of change in one-side etching according to the number of treated sheets was poor, making them unsuitable for use. In the case of Comparative Example 7 containing ammonium citrate, the amount of change in one-side etching depending on the number of treated sheets was poor, so it was confirmed that they were unsuitable for use. It was confirmed to be unsuitable for use.

In the case of Comparative Example 8, it was confirmed that the change in one-sided etching according to the number of treated sheets was poor, and that the lower IGZO film was damaged by ammonium bifluoride, making it unsuitable for use.

Claims (8)

With respect to the total weight of the etchant composition,
(A) 5 to 25% by weight of hydrogen peroxide,
(B) 0.1 to 5% by weight of azole compound,
(C) 0.1 to 5% by weight of a water-soluble compound having a nitrogen atom and a carboxyl group in one molecule,
(D) 0.1 to 5% by weight of phosphate,
(E) 0.1 to 5% by weight of acetate,
(F) 0.01 to 5% by weight of polyhydric alcohol-type surfactant, and
(G) contains water remaining;
The etchant composition does not contain fluorine-based compounds,
In the etchant composition for a copper-based metal film, characterized in that when etching the copper-based metal film on the lower metal oxide film with the etchant composition, the etching rate of the lower metal oxide film is less than 1.0 Å/sec,
The metal oxide film is a ternary or four-component oxide represented by AxByCzO, an etchant composition for a copper-based metal film:
(A, B and C are each independently zinc (Zn), titanium (Ti), cadmium (Cd), gallium (Ga), indium (In), tin (Sn), hafnium (Hf), zirconium ( It is a metal selected from the group consisting of Zr) and tantalum (Ta),
x, y and z represent the ratio of each metal and are an integer or decimal number greater than or equal to 0.) In claim 1,
Specific examples of the azole-based compounds include triazole-based, aminotetrazole-based, imidazole-based, indole-based, purine-based, pyrazole-based, A copper-based metal comprising at least one selected from pyridine-based, pyrimidine-based, pyrrole-based, pyrrolidine-based and pyrroline-based compounds. Etch composition for membranes. In claim 1,
Water-soluble compounds having a nitrogen atom and a carboxyl group in one molecule include alanine, aminobutyric acid, glutamic acid, glycine, iminodiacetic acid, and nitrilotriacetic acid. ) and sarcosine. In claim 1,
The phosphates include monobasic sodium phosphate (NaH ₂ PO ₄ ), dibasic sodium phosphate (Na ₂ HPO ₄ ), tribasic sodium phosphate (Na ₃ PO ₄ ), monobasic potassium phosphate (KH ₂ PO ₄ ), and dibasic phosphate. Potassium (K ₂ HPO ₄ ), monobasic ammonium phosphate ((NH ₄ )H ₂ PO ₄ ), diammonium phosphate ((NH ₄ ) ₂ HPO ₄ ) and tertiary ammonium phosphate ((NH ₄ ) ₃ PO ₄ ). An etchant composition for a copper-based metal film, comprising at least one selected from the group consisting of In claim 1,
The etchant composition for a copper-based metal film, wherein the acetate includes at least one selected from potassium acetate (CH ₃ COOK), sodium acetate (CH ₃ COONa), and ammonium acetate (CH ₃ COONH ₄ ). In claim 1,
An etchant composition for a copper-based metal film, wherein the polyhydric alcohol-type surfactant includes at least one selected from glycerol, ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol. In claim 1,
The copper-based metal film may be a single film of copper or copper alloy; Or an etchant composition for a copper-based metal film, characterized in that it is a multilayer film comprising at least one film selected from a copper film and a copper alloy film, and one or more films selected from a molybdenum film and a molybdenum alloy film. a) forming gate wiring on the substrate;
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 source and drain electrodes on the semiconductor layer; and
e) forming a pixel electrode connected to the drain electrode; In the method of manufacturing an array substrate for a display device comprising:
Step a) includes forming a copper-based metal film on a substrate, etching the copper-based metal film with the etchant composition for a copper-based metal film of claim 1 to form a gate wiring,
The step d) includes forming a copper-based metal film on the semiconductor layer and etching the copper-based metal film with the etchant composition for a copper-based metal film of claim 1 to form source and drain electrodes. Method for manufacturing an array substrate.