Copper-titanium structure etching composition and preparation method thereof

Abstract

The invention relates to the technical field of etching solutions, in particular to a copper-titanium structure etching composition and a preparation method thereof.The copper-titanium structure etching composition at least comprises, by mass, 12%-20% of hydrogen peroxide, 2%-10% of organic acid, 1%-8% of organic acid ammonium, 0.01%-1.5% of corrosion inhibitors, 0.1%-5% of amino acid, 0.01%-1% of fluorine-containing compounds, 0.1%-3% of stabilizers and the balance deionized water. The composition can etch copper and titanium at one time, is suitable for etching a fine pattern or a compact structure with high pattern density per unit area, and minimizes process defects.

Description

Technical Field

[0001] The invention relates to the technical field of etching solutions, in particular to a copper-titanium structure etching composition and a preparation method thereof. Background Art

[0002] In order to etch the titanium component at one time with copper metal and barrier metal layer, in the related etching technology related patents in the past, persulfate was used as an oxidant, and then a large amount of inhibitors and fluorine compounds were used for etching. When using conventional technology, due to the addition of a large amount of fluorine, the glass substrate and etching equipment will be damaged, resulting in multiple defects. Due to these problems, when titanium is used as a barrier metal layer, when the Source / Drain wiring is formed in the TFT process, when the lower active layer is an oxide semiconductor (IGZO), it will cause serious damage to the IGZO, so conventional technology can no longer meet the current technical requirements. For example, a Chinese patent (authorization announcement number is CN106086891B) discloses a high-generation flat copper-titanium film acid etching solution, which mainly introduces a large amount of ammonium fluoride into the system to ensure etching performance, but it will inevitably damage the glass substrate and etching equipment, and cannot meet the actual application requirements. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a copper-titanium structure etching composition, which can achieve one-time etching of copper and titanium, is suitable for etching fine patterns or a compact structure with high pattern density per unit area, and minimizes process defects.

[0004] On the one hand, the present invention provides a copper-titanium structure etching composition, which comprises at least the following components by mass percentage: 12-20% hydrogen peroxide, 2-10% organic acid, 1-8% organic acid ammonium, 0.01-1.5% corrosion inhibitor, 0.1-5% amino acid, 0.01-1% fluorine-containing compound, 0.1-3% stabilizer, and deionized water to make up the balance.

[0005] As a preferred technical solution, the copper-titanium structure etching composition comprises the following components, calculated by weight: 10-30% hydrogen peroxide, 3-8% organic acid, 2-4% organic acid ammonium, 0.05-0.5% corrosion inhibitor, 0.5-2% amino acid, 0.05-0.2% fluorine-containing compound, 0.5-2% stabilizer, and deionized water to make up the balance.

[0006] As a preferred technical solution, the organic acid is a non-nitrogen-containing organic acid having one or more carboxyl groups, including at least one of acetic acid, formic acid, butanic acid, citric acid, glycolic acid, oxalic acid, malonic acid, malic acid, pentanic acid, propionic acid, tartaric acid, gluconic acid, succinic acid, glutaric acid, and fumaric acid, preferably malonic acid.

[0007] As a preferred technical solution, the organic ammonium acid is selected from at least one of ammonium formate, ammonium acetate, ammonium propionate, ammonium butyrate, ammonium valerate, ammonium citrate, ammonium malonate, ammonium malate, ammonium oxalate, ammonium glycolate, ammonium succinate, ammonium tartrate, and ammonium fumarate, preferably ammonium citrate.

[0008] As a preferred technical solution, the corrosion inhibitor is at least one of a heterocyclic aromatic compound and a heterocyclic aliphatic compound.

[0009] Preferably, the heterocyclic aromatic compound is selected from at least one of furan, thiophene, pyrrole, oxazole, imidazole, pyrazole, triazole, tetrazole, 5-aminotetrazole and methyltetrazole.

[0010] Preferably, the heterocyclic aliphatic compound is at least one selected from piperazine, methylpiperazine, hydroxyethylpiperazine, pyrrolidine and alloxan.

[0011] Preferably, the corrosion inhibitor is 5-aminotetrazolyl.

[0012] As a preferred technical solution, the weight proportion of amino acid in the etching composition is 1-1.8%, preferably 1.2-1.5%.

[0013] Preferably, the amino acid is selected from at least one of glycine, alanine, valine, glutamic acid, aspartic acid, glutamine, asparagine, serine, threonine, methionine, histidine, paragine, serine, rinine and rine, and is preferably histidine.

[0014] As a preferred technical solution, the mass proportion of the fluorine-containing compound in the copper-titanium structure etching composition is 0.05-0.1%. The fluorine-containing compound is selected from at least one of ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride, and potassium bifluoride, preferably ammonium bifluoride.

[0015] As a preferred technical solution, the stabilizer is selected from at least one of polyethylene glycol, polybutylene glycol, polypropylene glycol, and polytetramethylene ether sugar. Preferably, the weight average molecular weight (MW) of the polyethylene glycol is 200-1500.

[0016] As a preferred technical solution, the copper-titanium structure etching composition also includes a pH regulator.

[0017] Preferably, the pH regulator is selected from NH4OH and / or TMAH (tetramethylammonium hydroxide).

[0018] Preferably, the pH adjuster adjusts the pH of the copper-titanium structure etching composition to 4-7, preferably 4.5-5.5.

[0019] The etching solution of the present invention is a composition for etching a copper and titanium multilayer film, the lower layer of which is a glass substrate or a semiconductor layer, and the semiconductor layer includes amorphous silicon or an oxide semiconductor IGZO. The present invention optimizes the etching composition formula so that the provided etching composition has excellent etching properties for copper and titanium, while having little or no damage to the exposed lower film. Specifically, by controlling the pH of the copper-titanium structure etching composition to be adjusted to 4-7 by adding 1-1.8wt% of amino acid in combination with a pH regulator, the etching effect is ensured, and the problems of metal residue, cracking after etching, too small taper angle, and damage to the lower oxide semiconductor IGZO are effectively avoided. The inventor analyzed that the reason may be: the present invention controls the pH of the etching composition to be 4-7, especially at a pH of 4.5-5.5, the residue after titanium etching is mainly TiO2H2O, so it can be effectively removed under the action of a small amount of fluorine compounds in the system, and even if the Over Etch is reduced to less than CD bias 0.5μm, there is no titanium residue. The introduction of amino acids, especially histidine, maximizes the synergistic effect with a small amount of fluorine-containing compounds added to the system, ensuring that copper and titanium maintain excellent etching properties while also forming a precise pattern structure.

[0020] Furthermore, the present invention controls the mass proportion of the fluorine-containing compound in the copper-titanium structure etching composition to 0.05-0.1%, thereby ensuring that the product after etching has no metal residue and meets the fine etching requirements.

[0021] On the other hand, the present invention provides a method for preparing a copper-titanium structure etching composition, which comprises at least the following steps: mixing hydrogen peroxide, organic acid, organic acid ammonium, corrosion inhibitor, amino acid, fluorine-containing compound, stabilizer and deionized water, and adjusting the pH of the system with a pH regulator to obtain the composition.

[0022] Beneficial Effects

[0023] 1. The present invention provides a copper-titanium structure etching composition. The present invention provides a copper-titanium structure etching composition, which can achieve one-time etching of copper and titanium, is suitable for etching fine patterns or a compact structure with a high pattern density per unit area, and minimizes process defects.

[0024] 2. The etching solution of the present invention is a composition for etching a copper and titanium multilayer film, wherein the lower layer is a glass substrate or a semiconductor layer, and the semiconductor layer includes amorphous silicon or an oxide semiconductor IGZO. The present invention optimizes the etching composition formula so that the provided etching composition has excellent etching properties for copper and titanium while causing little or no damage to the exposed lower film.

[0025] 3. The present invention controls the pH of the copper-titanium structure etching composition to be adjusted to 4-7 by adding 1-1.8wt% of amino acid in combination with a pH adjuster to the etching composition, thereby ensuring the etching effect and effectively avoiding the problems of metal residue, cracking after etching, too small taper angle, and damage to the underlying oxide semiconductor IGZO.

[0026] 4. The present invention controls the mass proportion of the fluorine-containing compound in the copper-titanium structure etching composition to 0.05-0.1%, thereby ensuring that the product after etching has no metal residue and meets the requirements of fine etching.

[0027] 5. The etching composition provided by the present invention adopts an etching system of malonic acid-ammonium citrate and cooperates with a sustained-release system of 5-aminotetrazolyl to ensure that the cross-sectional shape of the wiring formed after etching meets the requirements of fine etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1-4 The etching effect diagrams of the etching compositions provided in Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are respectively shown, wherein a is a SEM cross-sectional diagram after Cu / Ti etching, and b is a SEM diagram of damage to the lower film IGZO. DETAILED DESCRIPTION

[0029] Examples 1-5, Comparative Examples 1-3

[0030] Examples 1-5 and Comparative Examples 1-3 of the present invention provide a copper-titanium structure etching composition, and the formula is shown in Table 1 in terms of mass percentage.

[0031] Table 1

[0032]

[0033] On the other hand, Examples 1-5 and Comparative Examples 1-3 of the present invention provide a method for preparing a copper-titanium structure etching composition, comprising the following steps: mixing hydrogen peroxide, organic acid, organic acid ammonium, corrosion inhibitor, amino acid, fluorine-containing compound, stabilizer, and deionized water, and then adjusting the pH of the system with a pH adjuster to obtain the composition.

[0034] Performance Testing

[0035] The etching solution composition provided in the embodiment and the comparative example is used for etching the copper-titanium two-layer film. The etching conditions and etching effects are shown in Table 2. The etching effects of embodiment 2, comparative example 1, comparative example 2, and comparative example 3 are shown in Table 3. Figure 1-4 .

[0036] Table 2

[0037]

[0038] From the analysis of the above table, it can be seen that the etching compositions provided in Examples 1-5 are used for etching copper-titanium structures with good morphology, no metal residue, no cracks, and the damage to the lower IGZO is Ti Tail≤0.02μm, CD-loss is 0.48-0.55μm, taper angle can be controlled at 39.5-40.9°, and the maximum copper loading is 4000-45000ppm.

[0039] contrast Figure 1-4 From a and b, it can be seen that the etching composition provided by Example 2 exhibits excellent etching performance, while the etching characteristics of Comparative Example 1 are poor, the etching characteristics of Comparative Example 2 are poor in residue, and the etching characteristics of Comparative Example 3 are poor.

Claims

1. A copper-titanium structure etching composition, characterized in that: Calculated by mass percentage, it includes at least the following components: 12-20% hydrogen peroxide, 2-10% organic acid, 1-8% organic acid ammonium, 0.01-1.5% corrosion inhibitor, 0.1-5% amino acid, 0.01-1% fluorine-containing compound, 0.1-3% stabilizer, and deionized water to make up the balance.

2. The copper-titanium structure etching composition according to claim 1, characterized in that: The copper-titanium structure etching composition further comprises a pH adjuster, and the pH adjuster adjusts the pH of the copper-titanium structure etching composition to 4-7.

3. The copper-titanium structure etching composition according to claim 2, characterized in that: The organic acid is a non-nitrogen-containing organic acid having one or more carboxyl groups, including at least one of acetic acid, formic acid, butyric acid, citric acid, glycolic acid, oxalic acid, malonic acid, malic acid, valeric acid, propionic acid, tartaric acid, gluconic acid, succinic acid, glutamic acid, and fumaric acid.

4. The copper-titanium structure etching composition according to claim 2, characterized in that: The organic ammonium acid is selected from at least one of ammonium formate, ammonium acetate, ammonium propionate, ammonium butyrate, ammonium valerate, ammonium citrate, ammonium malonate, ammonium malate, ammonium oxalate, ammonium glycolate, ammonium succinate, ammonium tartrate and ammonium fumarate.

5. The copper-titanium structure etching composition according to claim 2, characterized in that: The heterocyclic aromatic compound is selected from at least one of furan, thiophene, pyrrole, oxazole, imidazole, pyrazole, triazole, tetrazole, 5-aminotetrazolyl, and methyltetrazole.

6. The copper-titanium structure etching composition according to claim 2, characterized in that: The amino acid in the etching composition accounts for 1-1.8% by weight.

7. The copper-titanium structure etching composition according to claim 2, characterized in that: The amino acid is selected from at least one of glycine, alanine, valine, glutamic acid, aspartic acid, glutamine, asparagine, serine, threonine, cysteine, histidine, amphetamine, alaninamide, cysteinyl, and alanyl.

8. The copper-titanium structure etching composition according to claim 2, characterized in that: The mass proportion of the fluorine-containing compound in the copper-titanium structure etching composition is 0.05-0.1%.

9. The copper-titanium structure etching composition according to claim 2, characterized in that: The fluorine-containing compound is selected from at least one of ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride and potassium bifluoride.

10. A method for preparing the copper-titanium structure etching composition according to any one of claims 2 to 9, characterized in that: At least the following steps are included: The preparation method is prepared by mixing hydrogen peroxide, organic acid, organic acid ammonium, corrosion inhibitor, amino acid, fluorine-containing compound, stabilizer and deionized water, and then adjusting the pH of the system with a pH adjuster.

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