Neutral copper etching solution and preparation method and application thereof

Abstract

The invention discloses a neutral copper etching solution and a preparation method and application thereof, and the neutral copper etching solution comprises the following components by mass: 1-10% of a copper salt, 10-20% of an organic acid, 8-20% of an organic amine compound, 0.1-10% of a copper etching accelerator, 0.1-2% of a metal oxide inhibitor, 0.1-2% of a wetting agent, and the balance of water. The neutral copper etching liquid provided by the invention can etch a copper layer and a metal oxide layer at the same time, the etching rate of pure copper and the metal oxide layer is adjusted by changing the content and the type of the copper accelerant and the metal oxide inhibitor, and the effect of flattening a circuit is achieved by adjusting the etching ratio. The etching solution is mild in use condition, neutral, small in corrosion to equipment, safe, environmentally friendly and high in etching efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of copper etching liquid, and in particular to a neutral copper etching liquid and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of semiconductor packaging and display panel technology, end users have increasingly higher requirements for product performance, such as higher transmission efficiency of electrical signals, smaller current loss, more stable transmission effect, and longer service life. In order to meet these requirements, the interconnect material in the semiconductor packaging and display panel process has gradually shifted from metal aluminum to metal copper. Metal copper has become an ideal choice to replace metal aluminum because of its lower impedance, higher mechanical strength, good heat dissipation performance and excellent anti-electromigration. Using copper as the interconnect material can effectively reduce the impedance and current loss of the interconnect in the process, increase the signal transmission speed, and streamline the process of the driver IC, thereby improving the performance and service life of the overall product.

[0003] In the process of semiconductor packaging and display panels, the formation of metal interconnects usually depends on the corresponding copper etching solution. These etching solutions etch the copper layer according to the photoresist pattern after the mask is developed to form the required interconnect structure. At present, hydrogen peroxide series copper etching solutions are widely used in the process of semiconductor packaging and display panels. However, hydrogen peroxide is easy to decompose to produce flammable gas oxygen, and a large amount of heat is generated during the decomposition process, which increases the risk of accidents such as combustion and even explosion, which is not conducive to the safe production and continuous production of enterprises. Therefore, the development of a safe, stable and efficient copper etching solution has become an urgent problem to be solved in the industry.

[0004] In addition, in the fields of optoelectronic display, circuit boards, etc., devices often have both metal oxide layers and copper layers. Traditional etching processes usually require etching the metal oxide layer and the copper layer separately, which not only increases the complexity of the process, but also increases production costs. In order to simplify the process and reduce costs, the industry has begun to explore neutral etching solutions that can etch metal oxide layers and copper layers at the same time. However, most of the existing neutral copper etching solutions only perform single etching on the copper layer, and do not reflect the differential etching capabilities of the copper layer and the metal oxide layer, making it difficult to achieve a smooth circuit effect.

[0005] Therefore, there is an urgent need to develop a neutral etching solution that can etch both the metal oxide layer and the copper layer at the same time to meet the demand for high-performance products in the fields of optoelectronic display, circuit boards, etc. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a neutral copper etching solution, which can etch the copper layer and the metal oxide layer at the same time through specific components and ratios, thereby realizing differential etching of the copper layer and the metal oxide layer, and achieving the effect of circuit flattening by adjusting the etching ratio.

[0007] A further object of the present invention is to provide a method for preparing the neutral copper etching solution, which can not only simplify the process and reduce costs, but also improve production efficiency.

[0008] The third object of the present invention is to provide an application of the neutral copper etching solution in the manufacturing process of a display panel.

[0009] The above object of the present invention is achieved through the following technical solutions:

[0010] The first aspect of the present invention provides a neutral copper etching solution, which comprises the following components by mass percentage: 1-10% of copper salt, 10-20% of organic acid, 8-20% of organic amine compound, 0.1-10% of copper etching accelerator, 0.1-2% of metal oxide inhibitor, 0.1-2% of wetting agent, and the balance is water; the copper etching accelerator is selected from one or more of 1,2,4-triazole, 2H-1,2,3-triazole, 3-amino-1,2,4-triazole, 3-cyano-1,2,4-triazole and benzotriazole; the metal oxide inhibitor is an amide compound containing a hydroxyl functional group.

[0011] The neutral copper etching solution provided by the present invention can simultaneously etch the copper layer and the metal oxide layer, and the etching rates of pure copper and the metal oxide layer are adjusted by changing the content and type of the copper accelerator and the metal oxide inhibitor. The copper etching accelerator can be complexed with the copper ions in the neutral copper etching solution to increase the copper etching rate, and the metal oxide inhibitor can maintain a certain protective film on the side of the metal oxide, thereby reducing the side corrosion and reducing the etching rate of the metal oxide; the copper etching accelerator and the metal oxide inhibitor are used at the same time to increase the copper etching rate and reduce the etching rate of the metal oxide, and the effect of line flatness is achieved by adjusting the etching ratio, and the increased etching ratio is much higher than the theoretical value, and the copper etching accelerator and the metal oxide inhibitor have a synergistic effect. The etching solution has mild use conditions, is neutral, has less corrosion to equipment, and is safe and environmentally friendly.

[0012] Furthermore, the copper salt is selected from one or more of copper sulfate, copper acetate, copper bromide, copper formate and copper nitrate.

[0013] Furthermore, the organic acid is selected from one or more of formic acid, acetic acid, benzoic acid, oxalic acid, malonic acid and succinic acid.

[0014] Furthermore, the organic amine compound is selected from one or more of monoethanolamine, diethanolamine and triethanolamine.

[0015] Further, the metal oxide inhibitor is selected from one or more of 4-hydroxybenzamide, 4-hydroxyphenylacetamide, 3-hydroxypropionamide, 2-hydroxypropionamide, 2-hydroxyisobutyramide, salicylamide, salicylanilide and 2,4-dihydroxybenzamide.

[0016] Furthermore, the wetting agent is selected from one or more of polyethylene glycol, polypropylene glycol, polyether and polyoxyethylene ether.

[0017] Furthermore, the pH value of the neutral copper etching solution is 5-9.

[0018] Preferably, the neutral copper etching solution comprises the following components by mass percentage: 2-5% copper salt, 10-15% organic acid, 10-15% organic amine compound, 2-5% copper etching accelerator, 0.5-1% metal oxide inhibitor, 0.1-2% wetting agent, and the balance is water.

[0019] The second aspect of the present invention provides a method for preparing the neutral copper etching solution described in the first aspect, comprising the following steps: mixing a copper salt, an organic acid, an organic amine compound, a copper etching accelerator, a metal oxide inhibitor, a wetting agent and water to obtain the neutral copper etching solution.

[0020] The third aspect of the present invention provides an application of the neutral copper etching solution described in the first aspect in the process of manufacturing a display panel. The neutral copper etching solution is suitable for manufacturing devices having a metal oxide layer and a copper layer alone or simultaneously, ensuring that the etching rates of the copper and metal oxide layers are balanced to make the circuit smooth and reduce side etching. The neutral copper etching solution is mainly used in the fields of optoelectronic displays, circuit boards, etc.

[0021] Specifically, the device is placed in a neutral copper etching solution at 25-40° C. for immersion or stirring etching.

[0022] Beneficial effects of the present invention:

[0023] The neutral copper etching solution provided by the present invention can simultaneously etch the copper layer and the metal oxide layer, adjust the etching rate of the pure copper and the metal oxide layer by changing the content and type of the copper accelerator and the metal oxide inhibitor, and achieve the effect of line flattening by adjusting the etching ratio. The etching solution has mild use conditions and is neutral, has less corrosion to equipment, is safe and environmentally friendly, and has high etching efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a diagram showing the etching effect of the neutral copper etching solution prepared in Example 1 on the device.

[0025] Figure 2 This is a diagram showing the etching effect of the neutral copper etching solution prepared in Comparative Example 2 on the device.

[0026] Figure 3 This is a diagram showing the etching effect of the neutral copper etching solution prepared in Comparative Example 3 on the device. DETAILED DESCRIPTION

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0028] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0029] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0030] Example 1

[0031] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% formic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0032] The preparation method of the neutral copper etching solution in this embodiment comprises the following steps: mixing copper sulfate, formic acid, monoethanolamine, 1,2,4-triazole, 4-hydroxybenzamide, polyethylene glycol 400 and water according to a mass ratio, stirring evenly, and obtaining a neutral copper etching solution.

[0033] Example 2

[0034] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% formic acid, 12% diethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0035] Example 3

[0036] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% formic acid, 12% triethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0037] Example 4

[0038] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0039] Example 5

[0040] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxyphenylacetamide, 0.5% polyethylene glycol 400, and the balance is water.

[0041] Example 6

[0042] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% 3-hydroxypropionamide, 0.5% polyethylene glycol 400, and the balance is water.

[0043] Example 7

[0044] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 2H-1,2,3-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0045] Example 8

[0046] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% benzotriazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0047] Example 9

[0048] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polypropylene glycol 400, and the balance is water.

[0049] Example 10

[0050] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 0.5% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0051] Embodiment 11

[0052] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 2% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0053] Example 12

[0054] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 10% acetic acid, 9% monoethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0055] Embodiment 13

[0056] A neutral copper etching solution comprises the following components by mass percentage: 5% copper acetate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0057] Embodiment 14

[0058] A neutral copper etching solution comprises the following components by mass percentage: 2% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0059] The preparation method of the neutral copper etching solution provided in Examples 2-14 is substantially the same as that in Example 1.

[0060] Comparative Example 1

[0061] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 0.5% polyethylene glycol 400, and the balance is water.

[0062] Comparative Example 2

[0063] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0064] Comparative Example 3

[0065] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 0.5% polyethylene glycol 400, and the balance is water.

[0066] Comparative Example 4

[0067] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% thiophene, 1% 4-hydroxybenzamide, 0.5% polyethylene glycol 400, and the balance is water.

[0068] Comparative Example 5

[0069] A neutral copper etching solution comprises the following components by mass percentage: 5% copper sulfate, 13% acetic acid, 12% monoethanolamine, 5% 1,2,4-triazole, 1% thiourea, 0.5% polyethylene glycol 400, and the balance is water.

[0070] The preparation methods of the neutral copper etching solutions provided in Comparative Examples 1-5 are substantially the same as those in Example 1.

[0071] Test Case

[0072] The etching effects of the neutral copper etching solutions prepared in Examples 1-14 and Comparative Examples 1-5 were tested using the following test methods:

[0073] The device (copper layer 500nm and metal oxide layer 30nm) was placed in a neutral copper etching solution at 35°C and immersed in etching for 3.5 minutes. After etching, the device was cleaned and dried. A 400x metallographic microscope was used to observe the device after etching and the etching uniformity (i.e., flatness). The flatness was scored on a scale of 1-10, with 1 being the worst and 10 being the best.

[0074] The etching rate of the neutral copper etching solution on the pure copper sheet and the metal oxide sheet was tested by the weighing method, and the etching ratio was calculated. The specific method was as follows: a 5×5 cm pure copper sheet and a metal oxide sheet were placed in a neutral copper etching solution at 35°C for immersion etching for 3.5 min, and the weight change before and after was weighed. The etching rate of the pure copper sheet and the metal oxide sheet was obtained according to the etching rate calculation formula. The etching rate calculation formula is v=△m / (S×t×ρ)×10000000, wherein v is the etching rate, in nm / min; △m is the weight difference before and after etching, in g; S is the metal immersion area, in cm 2 ; t is the immersion time, in min; ρ is the metal density, in g / cm 3 .

[0075] Test results such as Figure 1-Figure 3 As shown in Table 1:

[0076] Figure 1 The etching effect of the neutral copper etching solution prepared in Example 1 on the device is shown in FIG. Figure 1 It can be seen that the etched lines are uniform and smooth. Figure 2 This is a diagram showing the etching effect of the neutral copper etching solution prepared in Comparative Example 2 on the device. Figure 3 This is a diagram showing the etching effect of the neutral copper etching solution prepared in Comparative Example 3 on a device. The etched circuit is uneven and not smooth.

[0077] Table 1 Corresponding data table of the etching effect of neutral copper etching solution

[0078]

[0079]

[0080] The larger the etching ratio, the greater the copper etching rate and the smaller the metal oxide etching rate. The thickness of the copper layer and the metal oxide layer in the device is very different, so the etching ratio is increased to reduce the etching of the metal oxide to achieve the effect of circuit flatness. The test results show that increasing the copper etching accelerator can increase the copper etching rate, and increasing the metal oxide inhibitor can reduce the metal oxide etching rate. The combination of the two can further increase the etching ratio of copper to metal oxide. At the same time, the reduction in the content of organic acids and organic amine compounds will also reduce the etching ratio.

[0081] In addition, it can be seen from the test results that the copper etching rate is greatly affected by the type and content of copper salts, the content of organic amine compounds, and the type and content of copper etching accelerators; the metal oxide etching rate is greatly affected by the content of organic amine compounds and the type and content of metal oxide inhibitors; the compound use of copper etching accelerators and metal oxide inhibitors can further increase the etching ratio of copper to metal oxides, and the type of wetting agent has little effect on the etching ratio. Copper etching accelerators can effectively complex copper ions, so that the copper ions in the etching solution are in the best state, thereby promoting the copper etching rate and avoiding precipitation; metal oxide inhibitors chelate with metal oxides and attach to the oxide surface, thereby reducing the metal oxide etching rate.

[0082] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art should understand that other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A neutral copper etching solution, characterized in that The neutral copper etching solution comprises the following components by mass percentage: 1-10% copper salt, 10-20% organic acid, 8-20% organic amine compound, 0.1-10% copper etching accelerator, 0.1-2% metal oxide inhibitor, 0.1-2% wetting agent, and the balance is water; the copper etching accelerator is selected from one or more of 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-cyano-1,2,4-triazole and benzotriazole; the metal oxide inhibitor is an amide compound containing a hydroxyl functional group.

2. The neutral copper etching solution according to claim 1, characterized in that The copper salt is selected from one or more of copper sulfate, copper acetate, copper bromide, copper formate and copper nitrate.

3. The neutral copper etching solution according to claim 1, characterized in that The organic acid is selected from one or more of formic acid, acetic acid, benzoic acid, oxalic acid, malonic acid and succinic acid.

4. The neutral copper etching solution according to claim 1, characterized in that The organic amine compound is selected from one or more of monoethanolamine, diethanolamine and triethanolamine.

5. The neutral copper etching solution according to claim 1, characterized in that The metal oxide inhibitor is selected from one or more of 4-hydroxybenzamide, 4-hydroxyphenylacetamide, 3-hydroxypropionamide, 2-hydroxypropionamide, 2-hydroxyisobutyramide, salicylamide, salicylanilide and 2,4-dihydroxybenzamide.

6. The neutral copper etching solution according to claim 1, characterized in that The wetting agent is selected from one or more of polyethylene glycol, polypropylene glycol, polyether and polyoxyethylene ether.

7. The neutral copper etching solution according to claim 1, characterized in that The pH value of the neutral copper etching solution is 5-9.

8. A method for preparing the neutral copper etching solution according to any one of claims 1 to 7, characterized in that: The following steps are involved: The neutral copper etching solution is obtained by mixing copper salt, organic acid, organic amine compound, copper etching accelerator, metal oxide inhibitor, wetting agent and water.

9. Use of the neutral copper etching solution according to any one of claims 1 to 7 in a manufacturing process of a display panel.

10. The use according to claim 9, characterized in that: Place the device in a neutral copper etching solution at 25-40°C for immersion or stirring etching.

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