阅读说明：本技术 一种用于铜/钼（铌）/igzo膜层的刻蚀液及其制备方法和应用 (Etching liquid for copper/molybdenum (niobium)/IGZO film layer and preparation method and application thereof ) 是由 徐帅 张红伟 李闯 胡天齐 钱铁民 于 2020-07-08 设计创作，主要内容包括：本发明提供一种用于铜/钼(铌)/IGZO膜层的刻蚀液及其制备方法和应用,所述蚀刻液包括主剂和添加剂,所述主剂和添加剂中金属缓蚀剂均为氨基咔唑类金属缓蚀剂。本发明的刻蚀液能够实现对金属源漏电极和半导体层IGZO膜层的同步刻蚀,可降低光罩使用数量、简化IGZO-TFT制造工艺流程、提高企业生产效率、降低生产成本、确保产品品质,同时该蚀刻液的铜离子负载可达8000ppm,使用寿命更高。(The invention provides an etching solution for a copper/molybdenum (niobium)/IGZO film layer and a preparation method and application thereof. The etching solution can realize synchronous etching of the metal source-drain electrode and the semiconductor layer IGZO film layer, can reduce the number of used light shades, simplify the IGZO-TFT manufacturing process flow, improve the production efficiency of enterprises, reduce the production cost and ensure the product quality, and meanwhile, the copper ion load of the etching solution can reach 8000ppm and the service life is longer.)

1. The etching solution for the copper/molybdenum (niobium)/IGZO film layer is characterized by comprising a main agent and an additive, wherein metal corrosion inhibitors in the main agent and the additive are amino carbazole metal corrosion inhibitors.

2. The etching solution of claim 1, wherein the main agent and the additive further comprise a fluorine-containing ionic compound.

3. The etching solution according to claim 1 or 2, wherein the main agent comprises the following components by the total mass of 100%:

preferably, the main agent comprises the following components by the total mass of 100 percent:

4. etching liquid according to any one of claims 1 to 3, characterized in that the additive comprises the following components, based on 100% of the total mass of the additive:

preferably, the additive comprises the following components by the total mass of 100 percent:

5. the etching solution according to any one of claims 1 to 4, wherein the hydrogen peroxide is electronic grade hydrogen peroxide;

preferably, the fluoride ion-containing compound is selected from any one or a combination of at least two of hydrofluoric acid, ammonium fluoride, ammonium bifluoride or tetramethylammonium fluoride;

preferably, the fluorine-containing ionic compound is hydrofluoric acid, and further preferably, the main agent comprises 0.01-3% of hydrofluoric acid in percentage by mass;

preferably, the amine compound is a polyamine or an alcanolamine compound;

further, the amine compound comprises any one of ethylene diamine, propylene diamine, dimethylethanolamine, diethylaminopropylamine, diethylethanolamine, triethanolamine or isopropanolamine or a combination of at least two of the same;

preferably, the ammonium salt comprises any one of or a combination of at least two of tetramethylammonium hydroxide, trimethylammonium hydroxide, ammonium acetate, ammonium chloride, ammonium sulfate, or ammonium nitrate.

6. The etching liquid according to any one of claims 1 to 5, wherein the hydrogen peroxide stabilizer is selected from urea and/or sulfonic acid compounds;

preferably, the urea compound comprises any one of phenyl urea, thiourea or urea or a combination of at least two thereof;

preferably, the sulfonic acid compound comprises p-hydroxybenzene sulfonic acid and/or p-aminobenzene sulfonic acid.

7. The etching solution according to any one of claims 1 to 6, wherein the aminocarbazole compound is 9-aminocarbazole and/or 3, 9-diaminocarbazole.

8. The method for preparing etching liquid according to any one of claims 1 to 7, comprising the steps of:

(1) mixing and stirring hydrogen peroxide, nitric acid, a fluorine-containing ionic compound, an amine compound and/or an ammonium salt, a hydrogen peroxide stabilizer and a metal corrosion inhibitor in water to obtain an etching liquid main agent;

(2) mixing and stirring nitric acid, a fluorine-containing ionic compound, an amine compound or ammonium salt and a metal corrosion inhibitor in water to obtain an etching liquid additive, namely the etching liquid for the copper/molybdenum (niobium)/IGZO film layer.

9. The method of claim 8, wherein the temperature of the mixing in step (1) and step (2) is maintained below 45 ℃.

10. An etching method of a copper/molybdenum (niobium)/IGZO film layer, characterized in that the etching method is performed using the etching solution according to any one of claims 1 to 7.

Technical Field

The invention belongs to the field of metal surface chemical treatment, and relates to etching liquid for a copper/molybdenum (niobium)/IGZO film layer, and a preparation method and application thereof.

Background

A Thin Film Transistor (TFT) is used as a core component of a flat panel display to control the switching and color change of the display panel. The TFT device is composed of a plurality of layers of films which are overlapped together, each functional film needs to pass through a plurality of photomask processes, each photomask process comprises the steps of film coating, photoresist coating, exposure, development, etching, photoresist stripping and the like, and a large amount of cost is consumed. Therefore, the number of mask processes directly determines the production cost of the display panel.

In the conventional basic TFT manufacturing process, the film layers that need to be used in the photomask process are a gate electrode, an active layer, a source/drain electrode (S/D) layer, a pixel through-hole electrode layer, and a pixel electrode layer. At present, a Si-TFT can realize a production process of at least 4 photomasks, two film layers of an active layer and an S/D layer share one halftone photomask (HTM) photomask, the S/D layer is wet-etched by using a chemical solution, and the Si film layer is dry-etched. The specific steps are that after the resist layer on the S/D is exposed and developed by HTM, (i) the S/D metal layer outside the trench is removed by using a metal etching solution, (ii) an unnecessary Si layer is removed by a dry etching process, (iii) the photoresist on the trench is removed by ashing, (iiii) the metal in the trench is removed by using the metal etching solution, and (iiii) the photoresist is stripped. The IGZO-TFT top-order process still requires 5 mask processes, and the production cost is still high, so that the enterprise faces a huge cost pressure.

The chemical properties of the IGZO and S/D metal film layers are greatly different, etching solutions with different properties are needed for etching respectively, and at present, no etching solution with good etching characteristics for both S/D and IGZO exists, so that 4mask-IGZO-TFT is not produced in mass. If the common characteristics of the S/D metal etching solution and the IGZO etching solution can be mixed to develop the etching solution, the 4mask-IGZO-TFT process can be realized. The 4mask-IGZO-TFT process comprises the following steps that after the resist layer on the S/D is exposed and developed through HTM, (i) the S/D metal layer and the IGZO layer outside the channel are removed through etching liquid, (ii) the photoresist above the channel is removed through ashing, (iii) the metal in the channel is removed through the S/D metal etching liquid, and (iiii) the photoresist is stripped.

Therefore, in order to shorten the production process of the IGZO-TFT and increase the enterprise efficiency, it is necessary to develop an etching solution capable of simultaneously etching the IGZO active layer and the S/D source/drain electrodes. In addition, in order to better control the etching direction and the etching rate and obtain a better wiring shape, azole corrosion inhibitors such as 5-aminotetrazole, 3-aminotriazole and the like are often added in the existing hydrogen peroxide etching solution, but the price of the azole corrosion inhibitors is quite high (the unit price per kilogram is as high as 800-900 yuan), and the profit level of enterprises is influenced.

Therefore, reducing the production cost of the chemical solution is also a concern for each chemical solution manufacturer on the basis of ensuring the etching characteristics of the chemical solution and the electrical characteristics (even better) of the product.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide an etching solution for a copper/molybdenum (niobium)/IGZO film layer, and a preparation method and application thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

in one aspect, the invention provides an etching solution for a copper/molybdenum (niobium)/IGZO film layer, which comprises a main agent and an additive, wherein metal corrosion inhibitors in the main agent and the additive are amino carbazole metal corrosion inhibitors.

According to the invention, the amino carbazole metal corrosion inhibitor is selected as the metal corrosion inhibitor in the main agent and the additive, so that the product cost is reduced, and on the other hand, the corrosion inhibitor can obtain good etching morphology without influencing the electrical characteristics of the product.

In order to guarantee the etching rate, preferably, the main agent and the additive also comprise fluorine-containing ionic compounds.

Preferably, the main agent comprises the following components by the total mass of 100 percent:

in the invention, the formula composition of the main agent is screened, and the matching of the components can reduce the cost on one hand and improve the service life and the etching stability of the etching solution on the other hand.

In the main agent of the present invention, the hydrogen peroxide may be contained in an amount of 1%, 3%, 5%, 8%, 10%, 12%, 14%, 16%, 18%, or 20% by mass.

In the main agent of the invention, the nitric acid (as its solute HNO)₃Calculated) may be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% by mass.

In the main agent of the present invention, the fluorine-containing ionic compound may be contained in an amount of 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5% by mass.

In the main agent of the present invention, the content of the amine compound or the ammonium salt may be 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% by mass.

In the main agent of the present invention, the hydrogen peroxide stabilizer may be contained in an amount of 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 2%, 3%, 4% or 5% by mass.

In the main agent of the present invention, the metal corrosion inhibitor may be contained in an amount of 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, or 2% by mass.

As a preferred technical scheme, the main agent comprises the following components by the total mass of 100 percent:

preferably, the additive comprises the following components by the total mass of 100 percent:

in the additive of the invention, the nitric acid (as its solute HNO)₃Calculated) may be 1%, 3%, 5%, 8%, 10%, 12%, 14%, 16%, 18% or 20% by mass.

In the additive of the present invention, the fluorine-containing ionic compound may be contained in an amount of 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% by mass.

In the additive of the present invention, the content of the amine compound or the ammonium salt may be 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 16%, 18%, or 20% by mass.

In the additive of the present invention, the metal corrosion inhibitor may be present in an amount of 0.01%, 0.03%, 0.05%, 0.08%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 1.8%, or 2% by mass.

As a preferred technical scheme, the additive comprises the following components by the total mass of 100 percent:

the copper/molybdenum (niobium)/IGZO film layer in the present invention means a metal copper layer/metal molybdenum layer/IGZO film layer, or a metal copper layer/molybdenum niobium alloy layer/IGZO film layer.

To say thatIt is clear that, in the invention, the mass percent of the hydrogen peroxide is calculated by the hydrogen peroxide in the hydrogen peroxide, and the mass percent of the nitric acid is calculated by the solute HNO in the nitric acid₃And (4) counting.

According to the technical scheme provided by the invention, through the chemical and electrochemical actions between different compounds with different mass percentages and an etching target object, the target film layer can be simultaneously converted into a free ionic compound to be etched, the etching appearance is good, the etching precision is high, the CD loss is less than 1 mu m, the gradient angle of 35 degrees is less than 60 degrees, and meanwhile, the electrical characteristics of each film layer cannot be damaged.

Specifically, the strong oxidant hydrogen peroxide in the etching solution of the invention has an oxidation reaction with elemental substances of metal copper, metal molybdenum (niobium) and unoxidized indium, gallium and zinc in IGZO, and changes the structure of the film layer. Subsequently, nitric acid in the system and substances such as copper oxide, zinc oxide and the like are subjected to acidification reaction, so that the substances are converted from a solid state to a free state. The amine or ammonium salt in the system is matched with the oxides of molybdenum and niobium to dissolve the oxides in the solution. The fluoride in the system reacts with gallium oxide, indium oxide and the like to generate metal fluo-late ions. Therefore, the etching solution of the invention can realize the synchronous etching of the copper/molybdenum (niobium)/IGZO film layer.

In addition, in order to have a proper etching rate ratio of the above components to each film layer, wherein the etching rate of the copper metal film is the highest, a metal corrosion inhibitor needs to be added into the system. In order to increase the storage period of the etching solution, a hydrogen peroxide stabilizer is added into the system to reduce the decomposition speed of the hydrogen peroxide.

The amine compound or the ammonium salt can form a complex with a metal oxide or a copper ion, so that the catalytic decomposition of free copper ions on hydrogen peroxide is reduced, which is extremely important for the high copper ion loading capacity of the etching solution. Meanwhile, the pH value of the etching solution can be adjusted, the pH value is prevented from greatly fluctuating due to consumption of nitric acid, and the etching solution has the effect of stabilizing the etching characteristic.

Preferably, the hydrogen peroxide is electronic grade hydrogen peroxide, and the reagent can oxidize elemental metal into metal oxide.

Preferably, the fluorine-containing ionic compound is selected from but not limited to hydrofluoric acid (when hydrofluoric acid is selected, the mass percentage of the fluorine-containing ionic compound is calculated by solute HF in hydrofluoric acid), ammonium fluoride, ammonium bifluoride or tetramethylammonium fluoride, or the combination of at least two of the ammonium bifluoride, the ammonium bifluoride and the tetramethylammonium bifluoride.

Preferably, the fluorine-containing ionic compound is hydrofluoric acid, and further preferably, the main agent comprises 0.01-3% by mass of hydrofluoric acid.

The amine compound and the ammonium salt play a role in pH buffering, can stabilize the pH value of the solution and stabilize the etching effect. Meanwhile, the copper ions can be complexed with the copper ions, so that the catalytic decomposition effect of the copper ions on the hydrogen peroxide is weakened, and the service life of the etching solution is prolonged.

Preferably, the amine compound is a polyamine or an alcanolamine compound.

Further, the amine compound includes any one of ethylenediamine, propylenediamine, dimethylethanolamine, diethylaminopropylamine, diethylethanolamine, triethanolamine, or isopropanolamine, or a combination of at least two thereof.

Preferably, the ammonium salt comprises any one of or a combination of at least two of tetramethylammonium hydroxide, trimethylammonium hydroxide, ammonium acetate, ammonium chloride, ammonium sulfate, or ammonium nitrate.

Of course, the amine compound and the ammonium salt in the etching solution may be used alone or in combination, and the ratio of the two compounds when used in combination is not particularly limited in the present invention.

The hydrogen peroxide stabilizer can be used for inhibiting the catalytic decomposition effect of trace metal ions on hydrogen peroxide in the storage process of the etching solution, reducing the decomposition rate of the hydrogen peroxide and prolonging the storage and service life of the etching solution. Specifically, the hydrogen peroxide stabilizer of the present invention is selected from urea compounds and/or sulfonic acid compounds. Preferably, the urea compound includes, but is not limited to, any one or a combination of at least two of phenylurea, thiourea, or urea; preferably, the sulfonic acid compound includes, but is not limited to, p-hydroxybenzene sulfonic acid and/or sulfanilic acid.

The metal corrosion inhibitor is an amino azole compound. Because the etching rate of copper metal is higher than that of molybdenum-niobium alloy, if a metal slow release agent is not added, the molybdenum-niobium layer is seriously trailing, and the electrical property is poor.

Specifically, in order to obtain better copper loading capacity and prolong the service life of the etching solution, the metal corrosion inhibitor is selected from amino carbazole compounds, preferably 9-amino carbazole and/or 3, 9-diamino carbazole. If the metal corrosion inhibitor in the etching solution is two or more of aminocarbazole compounds, the ratio between the compounds is not particularly limited in the present invention.

The second aspect of the present invention provides a method for preparing the etching solution for a copper/molybdenum (niobium)/IGZO film layer as described above, comprising the steps of:

(1) mixing and stirring hydrogen peroxide, nitric acid, a fluorine-containing ionic compound, an amine compound and/or an ammonium salt, a hydrogen peroxide stabilizer and a metal corrosion inhibitor in water to obtain an etching liquid main agent for a copper/molybdenum (niobium)/IGZO film layer;

(2) mixing and stirring nitric acid, a fluorine-containing ionic compound, an amine compound or ammonium salt and a metal corrosion inhibitor in water to obtain the etching liquid additive for the copper/molybdenum (niobium)/IGZO film layer, namely obtaining the etching liquid for the copper/molybdenum (niobium)/IGZO film layer.

In the preparation method, the mass percentage of each component in the etching solution is the same as that described above, and the details are not repeated here.

Specifically, nitric acid and water are mixed and stirred to produce the etching solution base, and the temperature is maintained at 45 ℃ or lower (for example, 45 ℃, 40 ℃, 38 ℃, 35 ℃, 30 ℃, 28 ℃, 25 ℃, 20 ℃ or the like). Then sequentially adding a fluorine-containing ionic compound, an amine compound and/or an ammonium salt, a hydrogen peroxide stabilizer, a metal corrosion inhibitor and hydrogen peroxide into the mixed system, and filtering the mixture by using 0.5 mu m and 0.2 mu m filter elements to obtain the catalyst. The temperature of the liquid medicine system is maintained below 45 ℃ so as to avoid the decomposition or mutual side reaction of the components of the liquid medicine at higher temperature.

Specifically, in order to produce the etching solution additive, nitric acid and water are mixed and stirred, and the temperature is maintained at 45 ℃ or lower (for example, 45 ℃, 40 ℃, 38 ℃, 35 ℃, 30 ℃, 28 ℃, 25 ℃, 20 ℃ or the like). Then sequentially adding a fluorine-containing ionic compound, an amine compound and/or an ammonium salt and a metal corrosion inhibitor into the mixed system, and filtering by using 0.5 mu m and 0.2 mu m filter elements. The temperature of the liquid medicine system is maintained below 45 ℃ so as to avoid the decomposition or mutual side reaction of the components of the liquid medicine at higher temperature.

The preparation method of the etching solution is simple, and the etching solution which is safe and can realize synchronous etching of the metal layer and the IGZO film layer in large-scale production and has excellent etching precision can be realized.

The third aspect of the invention provides an etching method of a copper/molybdenum (niobium)/IGZO film layer, wherein the etching method utilizes the etching solution to perform etching, the concentration of copper ions in the etching solution can be continuously increased along with the increase of the number of etched substrates, and 0.05-0.15% of additive in mass fraction needs to be added into a system when the concentration of copper ions is increased by 100 ppm. The etching method can realize synchronous etching of the metal layer and the IGZO film layer, and has stable etching characteristics and good uniformity.

Compared with the prior art, the invention has the following beneficial effects:

1. the etching liquid for the copper/molybdenum (niobium)/IGZO film layer realizes the synchronous etching of the metal source drain electrode and the semiconductor layer IGZO film layer through the electrochemical and chemical corrosion of different compositions and different film layers.

2. The etching liquid for the copper/molybdenum (niobium)/IGZO film layer stabilizes the etching rate ratio of the copper/molybdenum (niobium)/IGZO film layer by adjusting the proportion of different components, and obtains the electrical characteristics and the etching morphology which meet the product quality requirements, such as the single side of CD loss less than 1 mu m and the gradient angle of 30-60 degrees.

3. The etching solution for the copper/molybdenum (niobium)/IGZO film layer adopts the matching of the main agent and the auxiliary agent (namely the additive) to improve the copper ion loading capacity to 8000ppm, and has the characteristic of longer service life.

4. The etching solution for the copper/molybdenum (niobium)/IGZO film layer has the advantages of cheap and easily-obtained raw materials, and can help enterprises reduce cost and improve efficiency.

Drawings

FIG. 1A is an SEM photograph of a cross section and an etched surface of an etching solution of example 1 of the present invention at a copper ion concentration of 0ppm for 125s, with a scale of 1 μm;

FIG. 1B is an SEM photograph of the etched surface of the etching solution of example 1 of the present invention at a copper ion concentration of 0ppm for 125s, with a scale of 1 μm;

FIG. 2A is an SEM photograph showing a cross section of the etching solution of example 2 of the present invention, wherein the copper ion concentration is 0ppm and the etching time is 120s, and the scale is 1 μm;

FIG. 2B is an SEM photograph of the etched surface of the etching solution of example 2 of the present invention, taken at a copper ion concentration of 0ppm for 120s, with a scale of 1 μm;

FIG. 3A is an SEM photograph of a cross section of an etching solution of comparative example 1 of the present invention at a copper ion concentration of 0ppm for 300s, with a scale of 1 μm;

FIG. 3B is an SEM image of an etched surface of the etching solution of comparative example 1 of the present invention at a copper ion concentration of 0ppm for 300s, with a scale of 1 μm;

FIG. 4A is an SEM photograph of a cross-section of an etching solution of example 1 of the present invention, showing a copper ion concentration of 2000ppm and etching time of 125s, and showing a scale of 1 μm;

FIG. 4B is an SEM photograph of the etched surface of the etching solution of example 1 of the present invention at a copper ion concentration of 2000ppm for 125s, with a scale of 1 μm;

FIG. 5A is an SEM photograph of a cross-section of an etching solution of example 1 of the present invention, wherein the copper ion concentration is 4000ppm and the etching time is 125s, and the scale is 1 μm;

FIG. 5B is an SEM photograph of the etched surface of the etching solution of example 1 of the present invention at a copper ion concentration of 4000ppm for 125s, with a scale of 1 μm;

FIG. 6A is an SEM photograph of a cross-section of an etching solution of example 1 of the present invention at a copper ion concentration of 6000ppm for 125s, with a scale of 1 μm;

FIG. 6B is an SEM photograph of the etched surface of the etching solution of example 1 of the present invention at a copper ion concentration of 6000ppm and 125s etching, with a scale of 10 μm;

FIG. 7A is an SEM photograph showing a cross-section of an etching solution of example 1 of the present invention at a copper ion concentration of 8000ppm for 125s, with a scale of 1 μm;

FIG. 7B is an SEM photograph of the etched surface of the etching solution of example 1 of the present invention at a copper ion concentration of 8000ppm and etching time of 125s, with a scale of 1 μm;

FIG. 8A is an SEM photograph of a cross section of an etching solution of example 2 of the present invention, wherein the copper ion concentration is 2000ppm and the etching time is 120s, and the scale is 1 μm;

FIG. 8B is an SEM photograph of an etched surface of the etching solution of example 2 of the present invention, taken at a copper ion concentration of 2000ppm for 120s, with a scale of 1 μm;

FIG. 9A is an SEM photograph of a cross section of the etching solution of example 2 of the present invention, wherein the copper ion concentration is 4000ppm and the etching time is 120s, and the scale is 1 μm;

FIG. 9B is an SEM photograph of the etched surface of the etching solution of example 2 of the present invention, taken at a copper ion concentration of 4000ppm for 120s, with a scale of 1 μm;

FIG. 10A is an SEM photograph of a cross section of an etching solution of example 2 of the present invention, wherein the copper ion concentration is 6000ppm and the etching time is 120s, and the scale is 1 μm;

FIG. 10B is an SEM photograph of the etched surface of the etching solution of example 2 of the present invention, taken at a copper ion concentration of 6000ppm for 120s, with a scale of 1 μm;

FIG. 11A is an SEM photograph of a cross section of an etching solution of example 2 of the present invention, taken at a copper ion concentration of 8000ppm for 120s, with a scale of 1 μm;

FIG. 11B is an SEM photograph of an etched surface of the etching solution of example 2 of the present invention, taken at a copper ion concentration of 8000ppm for 120s, with a scale of 1 μm.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.