Cu alloy oxide one-step etching solution and preparation method thereof

Abstract

The invention relates to the technical field of etching solutions, in particular to a Cu alloy oxide one-step etching solution and a preparation method of the Cu alloy oxide one-step etching solution. The main agent at least comprises the following components in percentage by mass: 4.00%-8.00% of hydrogen peroxide, 0.50%-14.00% of organic acid, 0-2.2% of a pH regulator, 0.03%-0.4% of a fluorine-containing compound, 0.50%-1.00% of a stabilizer, 0.50%-2.00% of organic alkali, 0.20%-0.50% of an inhibitor, 0-1% of a purine group-containing compound and the balance of deionized water; the auxiliary agent at least comprises auxiliary organic acid, an auxiliary pH regulator, an auxiliary fluorine-containing compound, auxiliary organic alkali, an auxiliary inhibitor, an auxiliary stabilizer and deionized water. Through system optimization, one-step etching of the copper alloy and the oxide is realized under the condition of low hydrogen peroxide, and the problems of alloy layer chamfering, no vertical side wall of IGZO / sharp Tip and the like are solved.

Description

Technical Field

[0001] This invention relates to the field of etching solution technology, specifically to a one-step etching solution for Cu alloy oxides and its preparation method. Background Technology

[0002] Currently, hydrogen peroxide (H2O2) is a key oxidant in commercially available etching solutions, used to oxidize metals and regulate the etching rate. However, its chemical properties are unstable, easily decomposing to generate gas and heat, posing a risk of combustion and explosion. Furthermore, concentration fluctuations can affect process stability. In addition, when used for multilayer film etching, the different densities, chemical bonds, and etching mechanisms of different film layers lead to significant differences in their etching rates in traditional etching solutions. When the etching rates are mismatched, faster-etching layers will form "undercuts," while slower-etching layers will form "vertical" sidewalls or sharp "tips," the latter easily causing poor metal filling or tip discharge in subsequent processes.

[0003] A Taiwanese patent application (publication number TW201311934A) discloses a method for manufacturing a display device and an etching solution composition for a metal layer containing copper / metal oxide layers. By employing persulfate, fluorine compounds, inorganic acids, cyclic amine compounds, chlorine compounds, and organic acids, the provided etching solution composition is used to simultaneously etch copper and metal oxide layers, preventing over-cutting and improving process reliability. However, it cannot simultaneously guarantee excellent etching morphology (no vertical sidewalls / sharp tips) and a wide process window while also possessing high safety and environmental friendliness. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a one-step etching solution for Cu alloy oxides. Through system optimization, one-step etching of copper alloys and oxides is achieved under low hydrogen peroxide conditions, solving problems such as chamfering of alloy layers and the lack of vertical sidewalls / sharp tips in IGZO (indium gallium zinc oxide).

[0005] This invention provides a one-step etching solution for Cu alloy oxides, comprising a main agent and auxiliary agents. By mass percentage, the main agent comprises at least: 4.00-8.00% hydrogen peroxide, 0.50-14.00% organic acid, 0-2.2% pH adjuster, 0.03-0.4% fluorine-containing compound, 0.50-1.00% stabilizer, 0.50-2.00% organic base, 0.20-0.50% inhibitor, 0-1% purine-containing compound, and deionized water to make up the balance. The auxiliary agents comprise at least: auxiliary organic acid, auxiliary pH adjuster, auxiliary fluorine-containing compound, auxiliary organic base, auxiliary inhibitor, auxiliary stabilizer, and deionized water.

[0006] In one embodiment, the excipients, by mass percentage, include at least 16.00-30.00% auxiliary organic acid, 7.00-20.00% auxiliary pH adjuster, 0-5.00% auxiliary fluorine compound, 0-10.00% auxiliary organic base, 1.50-2.00% auxiliary inhibitor, 0-1.00% auxiliary stabilizer, and deionized water to make up the balance.

[0007] In one embodiment, the organic acid and the auxiliary organic acid are both selected from at least one of malonic acid, iminodiacetic acid, citric acid, glutamic acid, glycine, or lactic acid.

[0008] In one embodiment, the organic base and the auxiliary organic base are both selected from at least one of isopropanolamine, dimethylethanolamine, triethanolamine, diethylaminopropylamine, or tetramethylammonium hydroxide.

[0009] In one embodiment, the pH adjuster and the auxiliary pH adjuster are both selected from at least one of ammonium bisulfate, nitric acid, or phenolsulfonic acid.

[0010] In one embodiment, the fluorinated compound or auxiliary fluorinated compound is selected from ammonium bifluoride or hydrofluoric acid.

[0011] In one embodiment, the stabilizer and the auxiliary stabilizer are both selected from at least one of polyethylene glycol, 1,3-propanediol, or ethylene glycol butyl ether.

[0012] In one embodiment, the inhibitor and the co-inhibitor are both selected from at least one of 5-methyltetrazole, 5-aminotetrazole, 3-amino-1,2,4-triazole, vitamin B4, or tetramethylurea.

[0013] In one embodiment, the purine-containing compound is selected from at least one of 7H-purine or 3-methylxanthine.

[0014] In one embodiment, the amount of the purine-containing compound added is 0-0.5%.

[0015] In one embodiment, the amount of the purine-containing compound added is 0-0.1%.

[0016] This invention optimizes the amount of hydrogen peroxide added to the system to 4.00-8.00%, and, in combination with fluorine-containing compounds and other reagents, reduces oxidation side reactions and improves safety, while synchronizing the Cu oxidation rate with the IGZO etching rate to ensure etching effect.

[0017] Furthermore, by employing an optimized organic acid system in combination with a pH adjuster system, this invention avoids accelerated hydrogen peroxide decomposition or insufficient fluorine source activity without introducing phosphorus-containing compounds, thus ensuring the stability of etching performance. At the same time, it effectively avoids phosphate precipitation problems, reduces wastewater treatment costs, and better meets environmental regulations.

[0018] Furthermore, this invention introduces purine-containing compounds, 7H-purine or 3-methylxanthine, into the etching solution system, further controlling the addition amount of purine-containing compounds to <1%. This ensures that the provided etching solution produces no residue or chamfer when used for one-step etching of copper alloys and IGZO, and the IGZO etching tail is ≤0.1μm. The reason for this may be that the nitrogen atoms in the purine group form selective coordination bonds with the In / Ga / Zn metal ions on the IGZO surface, generating a dense protective layer that inhibits over-etching of IGZO. When the content is <0.1%, the insufficient protective layer leads to tailing; when it is >1%, the excessively thick protective layer hinders the etching reaction, resulting in incomplete etching.

[0019] Furthermore, by optimizing the combination of multiple inhibitors in the system, this invention balances the etching rate and etching selectivity, and controls the CD-loss (side etching) to ≤0.65μm.

[0020] Another aspect of the present invention provides a method for preparing a one-step etching solution for Cu alloy oxides, comprising at least the following steps: mixing the raw materials of the main agent to prepare the main agent, and mixing the raw materials for preparing the auxiliary agent to prepare the auxiliary agent.

[0021] The method of using the Cu alloy oxide one-step etching solution is as follows: use the main agent to etch the metal film layer. During the etching process, for every 1000ppm increase in copper ions, add 1.50% of the weight of the main agent as an auxiliary agent to the system. Control the etching temperature and the etching is complete.

[0022] Beneficial effects 1. This invention provides a one-step etching solution for Cu alloy oxides. Through system optimization, one-step etching of copper alloys and oxides is achieved under low hydrogen peroxide conditions, solving problems such as chamfering of alloy layers and lack of vertical sidewalls / sharp tips in IGZO (indium gallium zinc oxide).

[0023] 2. This invention optimizes the amount of hydrogen peroxide added to the system to 4.00-8.00%, and, in combination with fluorine-containing compounds and other reagents, reduces oxidation side reactions and improves safety, while synchronizing the Cu oxidation rate with the IGZO etching rate to ensure etching effect.

[0024] 3. This invention, by employing an optimized organic acid system and pH adjuster system, avoids accelerated hydrogen peroxide decomposition or insufficient fluorine source activity without introducing phosphorus-containing compounds, thus ensuring the stability of etching performance. At the same time, it effectively avoids phosphate precipitation problems, reduces wastewater treatment costs, and better meets environmental regulations.

[0025] 4. This invention introduces 7H-purine or 3-methylxanthine, compounds containing purine groups, into the etching solution system, and further controls the amount of purine group compounds added to be <1%, so that the provided etching solution has no residue and no chamfer when used for one-step etching of copper alloys and IGZO, and the IGZO etching tail is ≤0.1μm.

[0026] 5. This invention optimizes the combination of multiple inhibitors in the system to balance the etching rate and etching selectivity, thereby controlling the CD-loss (side etching) to ≤0.65μm. Attached Figure Description

[0027] Figure 1 The image is a SEM characterization of the Cu / MoNb / IGZO film after etching with the etching solution provided in Example 1.

[0028] Figure 2 SEM characterization image of the Cu / MoNb / IGZO film after etching with etching solution, as provided in Comparative Example 1. Detailed Implementation

[0029] Examples 1-6, Comparative Examples 1-6 Examples 1-6 and Comparative Examples 1-6 of the present invention provide a one-step etching solution for Cu alloy oxide, comprising a main agent and an auxiliary agent, the formulations of which are shown in Table 1 and Table 2 by mass percentage.

[0030] Table 1

[0031] Table 2

[0032] Blank spaces in Tables 1 and 2 indicate that the corresponding raw material addition amount is 0.

[0033] Examples 1-6 and Comparative Examples 1-6 of the present invention provide a method for preparing a one-step etching solution for Cu alloy oxide, comprising the following steps: mixing the raw materials of the main agent to prepare the main agent, and mixing the raw materials of the auxiliary agent to prepare the auxiliary agent.

[0034] The method of using the Cu alloy oxide one-step etching solution is as follows: use the main agent to etch the metal film layer. During the etching process, for every 1000ppm increase in copper ions, add 1.50% of the weight of the main agent as an auxiliary agent to the system. Control the etching temperature (32℃) and the etching is complete.

[0035] Performance testing 1. Etching Performance Evaluation: The etching compositions provided in the examples and comparative examples were used to etch Cu / MoNb / IGZO (copper-molybdenum-niobium / indium gallium zinc oxide) films. The etching conditions are shown in Table 3. After etching, the etching performance was confirmed using SEM analysis equipment. The results are shown in Table 4. Figure 1-2 .

[0036] 2. Maximum copper ion load (ppm): Starting from a copper ion concentration of 500ppm, the standard is to confirm a change of more than 10% in CD-loss (linewidth loss). The results are shown in Table 4.

[0037] Table 3

[0038] Table 4

[0039] Based on the data in Table 4 and Figure 1-2 It can be seen that, compared with Comparative Examples 1-6, the Cu alloy oxide one-step etching solution provided in Examples 1-6 has a better etching effect and better meets the needs of practical applications.

Claims

1. A one-step etching solution for Cu alloy oxides, characterized in that, Includes main agent and excipients; The main agent, by mass percentage, comprises at least: 4.00-8.00% hydrogen peroxide, 0.50-14.00% organic acid, 0-2.2% pH adjuster, 0.03-0.4% fluorine-containing compound, 0.50-1.00% stabilizer, 0.50-2.00% organic base, 0.20-0.50% inhibitor, 0-1% purine-containing compound, and deionized water to make up the balance; the excipients comprise at least auxiliary organic acid, auxiliary pH adjuster, auxiliary fluorine-containing compound, auxiliary organic base, auxiliary inhibitor, auxiliary stabilizer, and deionized water.

2. The Cu alloy oxide one-step etching solution according to claim 1, characterized in that, The excipients, by mass percentage, include at least 16.00-30.00% auxiliary organic acid, 7.00-20.00% auxiliary pH adjuster, 0-5.00% auxiliary fluorine compound, 0-10.00% auxiliary organic base, 1.50-2.00% auxiliary inhibitor, 0-1.00% auxiliary stabilizer, and deionized water to make up the balance.

3. The Cu alloy oxide one-step etching solution according to claim 1, characterized in that, The organic acid and auxiliary organic acid are each selected from at least one of malonic acid, iminodiacetic acid, citric acid, glutamic acid, glycine, or lactic acid.

4. The Cu alloy oxide one-step etching solution according to claim 1, characterized in that, The organic base and auxiliary organic base are both selected from at least one of isopropanolamine, dimethylethanolamine, triethanolamine, diethylaminopropylamine, or tetramethylammonium hydroxide.

5. The Cu alloy oxide one-step etching solution according to claim 1, characterized in that, The pH adjuster and auxiliary pH adjuster are both selected from at least one of ammonium bisulfate, nitric acid, or phenol sulfonic acid.

6. The one-step etching solution for Cu alloy oxides according to claim 1, characterized in that, The fluorinated compounds or auxiliary fluorinated compounds are selected from ammonium bifluoride or hydrofluoric acid.

7. The Cu alloy oxide one-step etching solution according to claim 1, characterized in that, The stabilizer and auxiliary stabilizer are both selected from at least one of polyethylene glycol, 1,3-propanediol, or ethylene glycol butyl ether.

8. The Cu alloy oxide one-step etching solution according to claim 1, characterized in that, The inhibitor and the co-inhibitor are each selected from at least one of 5-methyltetrazole, 5-aminotetrazole, 3-amino-1,2,4-triazole, vitamin B4, or tetramethylurea.

9. The Cu alloy oxide one-step etching solution according to claim 1, characterized in that, The purine-containing compound is selected from at least one of 7H-purine or 3-methylxanthine.

10. A method for preparing a one-step etching solution for Cu alloy oxides according to any one of claims 1-9, characterized in that, At least the following steps are included: The raw materials for the main agent are mixed to prepare the main agent, and the raw materials for the preparation of the excipients are mixed to prepare the excipients.

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