Cu-MoTi alloy multi-film etching solution composition and preparation method thereof

Abstract

The invention relates to the technical field of etching liquid compositions, in particular to a Cu-MoTi alloy multi-film etching liquid composition and a preparation method thereof.The Cu-MoTi alloy multi-film etching liquid composition at least comprises, by mass, 13.00%-25.00% of a metal oxidizing agent, 1.00%-5.00% of a chelating agent, 0.10%-4.00% of an auxiliary chelating agent, 0.10%-5.00% of an etching agent, 0.01%-3.00% of alkanolamine, 0.005%-1.00% of a fluorine compound, 0.01%-3.00% of a hydrogen peroxide stabilizer and 0.10%-1.00% of KOH, the etching solution has the advantages that anisotropy and isotropy of etching are effectively balanced, the problems of reverse taper angle and poor DO are solved, the etching solution has cost and performance advantages, and a high-reliability etching solution is provided for semiconductor manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of etching solution compositions, and specifically to a Cu-MoTi alloy multi-layer etching solution composition and a preparation method thereof. Background Art

[0002] The main steps of the 4Mask process are as follows. The first photolithography process: continuously deposit an amorphous silicon semiconductor layer and a source-drain metal layer, where the amorphous silicon layer is deposited by CVD and the metal layer is formed by PVD. The second photolithography process: coat a photoresist. The third photolithography process: expose (with different exposure amounts of light), develop, and etch the photoresist in the source-drain metal area of the area where metal is not required. Metal is etched wet, while amorphous silicon is etched dry. The fourth photolithography process: ashing the photoresist to expose the metal in the channel area, then performing wet etching of the metal and dry etching of N+Si, and stripping the photoresist. In the 4mask process, the fluoride content of the etching solution composition for 2W1D (1st wet etching -> 1st dry etching -> 2nd wet etching) used to form Source / Drain wiring is more than twice that of the traditional technology. When the fluorine content increases significantly, the phenomenon of increased etching solution penetration force occurs at the interface between the photoresist and copper, and the most significant problem is the loss of wiring at the step difference part. To solve these problems, the adhesion between the photoresist and copper is increased in the process, and the photolithography process is changed. However, after etching, problems such as a high taper angle of more than 90 degrees and poor etching morphology occur, and the probability of insulation film cracking after the subsequent organic insulating film process increases significantly. Chinese Patent Application (CN119040892A) discloses an etching solution for a copper-molybdenum-titanium structure and a preparation method thereof, which improves the problems of high taper angle and poor etching morphology by introducing 1,2-propanediol or ethylene glycol monobutyl ether into the etching solution system, but the etching rate needs to be further improved. Summary of the Invention

[0003] To solve the above problems, the present invention provides a Cu (copper)-MoTi (molybdenum-titanium) alloy multi-layer etching solution composition, which effectively balances the anisotropy and isotropy of etching, solves the problems of reverse taper angle (the abnormal angle of the metal sidewall after etching, affecting the subsequent interlayer dielectric filling and the reliability of electrical connection) and DO defects (open circuit or short circuit of the circuit due to uneven etching or residues), and has the advantages of both cost and performance, providing a highly reliable etching solution for semiconductor manufacturing.

[0004] On the one hand, the present invention provides a Cu-MoTi alloy multi-layer etching solution composition, which, by mass percentage, at least includes: metal oxidant 13.00-25.00%, chelating agent 1.00-5.00%, auxiliary chelating agent 0.10-4.00%, etching agent 0.10-5.00%, alkanolamine 0.01-3.00%, fluorine-based compound 0.005-1.00%, hydrogen peroxide stabilizer 0.01-3.00%, KOH 0.10-1.00%, and water to make up the balance.

[0005] In one embodiment, the mass proportion of alkanolamine in the Cu-MoTi alloy multi-layer etching solution composition is 0.05-2.00%.

[0006] In one embodiment, the Cu-MoTi alloy multi-layer etching solution composition, by mass percentage, at least includes: metal oxidant 14.00-19.00%, chelating agent 1.50-3.00%, auxiliary chelating agent 0.50-1.50%, etching agent 0.10-1.80%, alkanolamine 0.10-1.00%, fluorine-based compound 0.01-0.20%, hydrogen peroxide stabilizer 0.05-1.0%, KOH 0.20-0.80%, and water to make up the balance.

[0007] In one embodiment, the Cu-MoTi alloy multi-layer etching solution composition, by mass percentage, at least includes: metal oxidant 17.00-18.00%, chelating agent 2.00-2.50%, auxiliary chelating agent 0.80-1.20%, etching agent 0.75-1.10%, alkanolamine 0.25-0.30%, fluorine-based compound 0.05-0.15%, hydrogen peroxide stabilizer 0.1-0.5%, KOH 0.48-0.52%, and water to make up the balance.

[0008] In one embodiment, the metal oxidant is hydrogen peroxide.

[0009] In one embodiment, the chelating agent is selected from at least one of iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, carbamic acid (methylenephosphonic acid), ((1-hydroxyethane-1,1-diyl)bis(phosphonic acid)), ethylenediaminetetraacetic acid (methylenephosphonic acid), dimethylenetriaminepenta(methylenephosphonic acid), alanine, glutamic acid, aminobutyric acid, or glycine.

[0010] In one embodiment, the chelating agent is iminodiacetic acid.

[0011] In one embodiment, the auxiliary chelating agent is selected from 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, or succinic acid.

[0012] In one embodiment, the auxiliary chelating agent is malic acid.

[0013] In one embodiment, the etchant is selected from at least one of potassium bisulfate, sodium bisulfate, sodium sulfate, sodium persulfate, potassium persulfate, potassium sulfate, ammonium sulfate, or ammonium persulfate.

[0014] In one embodiment, the etchant is sodium sulfate.

[0015] In one embodiment, the alkanolamine is selected from at least one of triisopropanolamine, isopropanolamine, diisopropanolamine, diethylene glycol amine, hydroxyethyl ethylenediamine, hydroxyethylamine, N-methylethanolamine, diethanolamine, 2-[2-(2-aminoethoxy)ethoxy]ethanol triethanolamine, N-aminoethyl-N'-hydroxyethyl ethylenediamine, or N,N'-di(hydroxyethyl)-ethylenediamine.

[0016] In one embodiment, the alkanolamine is triisopropanolamine.

[0017] In one embodiment, the fluorine-based compound is selected from at least one of HF, NaF, KF, AlF3, HBF4, NH4F, NH4HF2, NaHF2, KHF2, or NH4BF4.

[0018] In one embodiment, the fluorine-based compound is NaHF2.

[0019] In one embodiment, the hydrogen peroxide stabilizer is selected from at least one of butylamine, pentylamine, octylamine, 2-ethyl-1-butylamine, 2-hexylamine, 2-ethyl-hexylamine, 2-ethyl-hexylamine, heptylamine, hexylamine, or cyclohexylamine.

[0020] In one embodiment, the hydrogen peroxide stabilizer is butylamine.

[0021] In semiconductor manufacturing, the formation of source / drain requires the definition of copper metal wiring through photolithography and etching processes. In traditional processes, problems such as poor DO and reverse taper angle (Taper angle > 90°) often occur. For example, in an etching solution system containing benzotriazole, during the actual etching process, lateral etching is overly inhibited, resulting in a higher etching rate at the bottom than at the top, forming an "inverted trapezoid" structure (reverse taper angle). In the present invention, by introducing alkanolamine into the optimized system, especially when triisopropanolamine is introduced, the problems of poor DO (Data open) and reverse taper angle (Taper angle > 90°) are effectively solved, the process defects are minimized to the greatest extent, and excellent etching characteristics are formed, thereby helping to reduce costs and improve the yield. Further, by controlling the addition amounts of various raw materials in the optimized system, especially controlling the amount of triisopropanolamine introduced into the system to be 0.10 - 0.80%, while balancing the etching rate, the etching morphology and line width loss are greatly improved, meeting the processing requirements of high-precision metal stacks.

[0022] The etching solution composition provided by the present invention adopts a chelating etching system of iminodiacetic acid + malic acid + sodium sulfate, in combination with a small amount of NaHF2, butylamine, and potassium hydroxide. In the presence of triisopropanolamine, after etching the Cu-MoTi alloy multi-layer film, the line width loss (single side) is 0.5 - 0.7 μm, the taper angle is 50 - 60°, the MoTi tailing is 0.02 μm, and the etching rate of the n+ layer is There is no residue, no cracking, no copper residue at the PR and copper interface, and the highest copper load is 7000 ppm.

[0023] On the other hand, the present invention provides a preparation method for an etching solution composition for a Cu-MoTi alloy multi-layer film, which at least includes the following steps: stirring and mixing a metal oxidant, a chelating agent, an auxiliary chelating agent, an etching agent, an alkanolamine, a fluorine-based compound, a hydrogen peroxide stabilizer, KOH, and water to obtain the product.

[0024] The production method of the etching solution composition provided by the present invention has a low process difficulty, can obtain products meeting the etching requirements in a safe and efficient manner, is convenient to use, and is easy to promote and apply.

[0025] Beneficial effects

[0026] 1. The present invention provides an etching solution composition for a Cu-MoTi alloy multi-layer film, which effectively balances the anisotropy and isotropy of etching, solves the problems of reverse taper angle and poor DO, has both cost and performance advantages, and provides a highly reliable etching solution for semiconductor manufacturing.

[0027] 2. When the present invention introduces alkanolamine, especially triisopropanolamine, into the optimized system, it effectively solves the problems of poor DO and reverse taper angle (Taper angle > 90°), minimizes process defects to the greatest extent, forms excellent etching characteristics, and thus helps to reduce costs and improve the yield.

[0028] 3. By controlling the addition amounts of various raw materials in the optimized system of the present invention, especially controlling the amount of triisopropanolamine introduced into the system to be 0.10 - 0.80%, while balancing the etching rate, it greatly improves the etching morphology and line width loss, meeting the processing requirements of high-precision metal multilayers.

[0029] 4. The etching solution composition provided by the present invention adopts a chelating etching system of iminodiacetic acid + malic acid + sodium sulfate, combined with a small amount of NaHF2, butylamine, and potassium hydroxide. In the presence of triisopropanolamine, it ensures that the line width loss (single side) after etching the Cu - MoTi alloy multi-film layer is 0.5 - 0.7 μm, the taper angle is 50 - 60°, the MoTi tailing is 0.02 μm, and the etching rate of the n+ layer is There is no residue, no cracking, no copper residue at the PR and copper interface, and the highest copper load is 7000 ppm.

[0030] 5. The production method of the etching solution composition provided by the present invention has low process difficulty, can obtain products meeting the etching requirements in a safe and efficient manner, is easy to use, and is easy to promote and apply. Brief Description of the Drawings

[0031] Figure 1 SEM characterization diagram of the Cu - MoTi film etched by the etching solution composition provided in Example 1.

[0032] Figure 2 SEM characterization diagram of the Cu - MoTi film etched by the etching solution composition provided in Comparative Example 1.

[0033] Figure 3 SEM characterization diagram of the Cu - MoTi film etched by the etching solution composition provided in Comparative Example 2.

[0034] Figure 4 SEM characterization diagram of the Cu - MoTi film etched by the etching solution composition provided in Comparative Example 3. Detailed Description of the Invention

[0035] Examples 1 - 4, Comparative Examples 1 - 3

[0036] Examples 1 - 4 and Comparative Examples 1 - 3 of the present invention provide an etching solution composition for Cu - MoTi alloy multi-film layers on the one hand. By mass percentage, the formula is shown in Table 1.

[0037] Table 1

[0038]

[0039]

[0040] Examples 1-4 and Comparative Examples 1-3 of the present invention provide a method for preparing a Cu-MoTi alloy multi-layer etching solution composition, comprising the following steps: stirring and mixing hydrogen peroxide, organic acid, organic acid salt, copper inhibitor, interface inhibitor, fluorine compound, alkylamine compound and water to obtain the solution.

[0041] Performance Test

[0042] 1. Evaluation of etching performance: The Cu-MoTi film was etched using the etching compositions provided in the examples and comparative examples. The etching conditions are shown in Table 2. After the etching was completed, an SEM analysis device was used to confirm the etching performance. The results are shown in Table 2 and Figures 1-4 .

[0043] 2. Maximum copper ion loading (ppm): Starting from a copper ion concentration of 500 ppm, the CD-loss (line width loss) was confirmed to have a change of more than 10%. The results are shown in Table 2.

[0044] Table 2

[0045]

[0046]

[0047] From the data in Table 2 and Figures 1-4 it can be seen that compared with Comparative Examples 1-3, the Cu-MoTi alloy multi-layer etching solution composition provided by Examples 1-4 can ensure excellent etching performance in all aspects and better meet the actual application requirements.

Claims

1. A Cu-MoTi alloy multi-layer etching solution composition, characterized in that: Calculated by mass percentage, it at least includes: 13.00-25.00% metal oxidant, 1.00-5.00% chelating agent, 0.10-4.00% auxiliary chelating agent, 0.10-5.00% etchant, 0.01-3.00% alkanolamine, 0.005-1.00% fluorine compound, 0.01-3.00% hydrogen peroxide stabilizer, 0.10-1.00% KOH, and the balance is made up of water.

2. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The mass proportion of alkanolamine in the Cu-MoTi alloy multi-layer etching solution composition is 0.05-2.00%.

3. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The Cu-MoTi alloy multi-film layer etching solution composition comprises, by mass percentage, at least: 14.00-19.00% of a metal oxidant, 1.50-3.00% of a chelating agent, 0.50-1.50% of an auxiliary chelating agent, 0.10-1.80% of an etchant, 0.10-1.00% of an alkanolamine, 0.01-0.20% of a fluorine compound, 0.05-1.0% of a hydrogen peroxide stabilizer, 0.20-0.80% of KOH, and the balance is made up of water.

4. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The chelating agent is selected from at least one of iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethyl trinitrovaleric acid, aminoformic acid (methylenephosphonic acid), ((1-hydroxyethane-1,1-diyl)bis(phosphonic acid)), ethylenediaminetetraacetic acid (methylenephosphonic acid), dimethylenetriaminepenta (methylenephosphonic acid), alanine, glutamic acid, aminobutyric acid or glycine.

5. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The auxiliary chelating agent is selected from 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 or succinic acid.

6. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The etchant is selected from at least one of potassium bisulfate, sodium bisulfate, sodium sulfate, sodium persulfate, potassium persulfate, potassium sulfate, ammonium sulfate or ammonium persulfate.

7. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The alkanolamine is selected from at least one of triisopropanolamine, isopropanolamine, diisopropanolamine, diglycolamine, hydroxyethylethylenediamine, hydroxyethylamine, N-methylaminoethanol, diethanolamine, 2-[2-(2-aminoethoxy)(ethoxy]ethanoltriethanolamine, N-aminoethyl-N'-hydroxyethylethylenediamine or N,N'-dihydroxyethyl-ethylenediamine.

8. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The fluorine compound is selected from at least one of HF, NaF, KF, AlF3, HBF4, NH4F, NH4HF2, NaHF2, KHF2 or NH4BF4.

9. The Cu-MoTi alloy multi-layer etching solution composition according to claim 1, characterized in that: The hydrogen peroxide stabilizer is selected from at least one of butylamine, pentylamine, octylamine, 2-ethyl-1-butylamine, 2-hexylamine, 2-ethyl-hexylamine, 2-ethyl-hexylamine, heptylamine, hexylamine or cyclohexylamine.

10. A method for preparing a Cu-MoTi alloy multi-layer etching solution composition according to any one of claims 1 to 9, characterized in that: At least the following steps are included: The preparation method is prepared by stirring and mixing a metal oxidant, a chelating agent, an auxiliary chelating agent, an etchant, an alkanolamine, a fluorine compound, a hydrogen peroxide stabilizer, KOH and water.

Images