A ti n removal composition with good compatibility to copper cobalt tungsten
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUBEI SINOPHORUS ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2024-02-28
- Publication Date
- 2026-06-26
AI Technical Summary
Existing TiN etching cleaning solutions cannot simultaneously achieve rapid removal of TiN while maintaining protective compatibility with Low-K materials and other metallic materials (Cu, Co, W).
A composition comprising an oxidant, an alkaline substance, a carboxylate, a corrosion inhibitor, and a chelating agent is used. The specific component ratio is 40%-70% oxidant, 1%-5% alkaline substance, 0.1%-2% carboxylate, 0.1%-4% corrosion inhibitor, 0.1%-1% chelating agent, and the balance water. By controlling the etching temperature at 20-60℃ and the etching time at 60s-300s, TiN can be rapidly removed while protecting Cu, Co, W, and Low-K materials.
The etching rate of TiN was >200 Å/min, while the etching rates of Cu, Co, W and Low-K were <2 Å/min, and the solution life was greater than 40 h, ensuring compatibility and protection for other materials.
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Figure CN118185711B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a TiN removal composition for the removal of TiN, a metal hard mask material, in advanced copper manufacturing processes. Background Technology
[0002] As semiconductor manufacturing processes continue to advance, the requirements for linewidth become increasingly stringent. Maintaining optimal pattern dimensions during pattern transfer necessitates a hard mask material resistant to dry etching. Metallic hard mask material TiN stands out among many materials due to its excellent pattern retention and contour control capabilities, as well as its superior selectivity for etching low-K materials. TiN needs to be removed after fulfilling its etch protection function. During TiN removal, other metal materials and low-K materials must be protected.
[0003] CN106226991A discloses a composition for removing PVD TiN hard masks from 28 / 20nm patterned wafers. The composition includes a peroxide, a base, a weak acid, an ammonium salt, a corrosion inhibitor, and the balance being a solvent. Its etching rate for PVD TiN can reach 200 Å / min, but the etching rate will be very high in the presence of a large amount of hydrogen peroxide.
[0004] CN105874568A discloses an aqueous removal composition having a pH in the range of 2-14 and an etching method for selectively removing, from a semiconductor substrate, a material with low dielectric constant, substantially composed of TiN, TaN, TiNxOy, TiW, W, or Ti or W; wherein the removal composition comprises at least one oxidant and a carboxylate compound. This TiN etching solution also exhibits very poor compatibility with W.
[0005] CN104730870B discloses a composition for stripping TiN hard masks and exhibiting a low etching rate for W. The composition comprises a solvent, a weakly coordinating anion, an amine, and at least two non-oxidizing trace metal ions. However, the presence of iron and copper ions in the composition often leads to low device yields in practical applications.
[0006] CN113430060A discloses a tungsten-compatible cleaning solution for removing TiN, but the etching rate of TiN by this cleaning solution is <100 Å / min. In addition, the composition contains about 2.5% hydrofluoric acid, and the presence of fluorine will accelerate the etching of Low-K.
[0007] Therefore, developing an etching cleaning solution that can quickly remove TiN hard mask metal and has strong protective compatibility with other metal materials (Cu, Co and W) and Low-K materials has become an urgent problem to be solved in this field. Summary of the Invention
[0008] The technical problem this invention aims to solve is that existing TiN etching and cleaning solutions cannot simultaneously achieve a high removal rate for TiN while maintaining protective compatibility with Low-K materials and other metallic materials (Cu, Co, and W). This invention addresses these technical problems through the following technical solution.
[0009] A TiN removal composition with good copper-cobalt-tungsten compatibility comprises the following components by mass fraction: 40%-70% oxidant, 1%-5% alkaline substance, 0.1%-2% carboxylate, 0.1%-4% corrosion inhibitor, 0.1%-1% chelating agent, and the balance being water, wherein the sum of the mass fractions of each component is 100%.
[0010] The oxidant is one or more of hydrogen peroxide, ammonium persulfate, urea peroxide, or peracetic acid.
[0011] The alkaline substance is one or more of monoethanolamine, triethanolamine, diethylene glycolamine, tetramethylammonium hydroxide, ammonium hydroxide, or triethylamine.
[0012] The carboxylate is one or more of ammonium formate, ammonium acetate, ammonium oxalate, ammonium lactate, ammonium tartrate, or triammonium citrate.
[0013] The corrosion inhibitors include corrosion inhibitor 1, corrosion inhibitor 2, and corrosion inhibitor 3; corrosion inhibitor 1 is N-acetylgalactosamine; corrosion inhibitor 2 is ticlopidine hydrochloride; and corrosion inhibitor 3 is one or more of benzotriazole, methylbenzotriazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, benzimidazole, 2-mercapto-1-methylimidazole, mercapto-benzothiazole, or 1-phenyl-5-mercaptotetrazole.
[0014] The chelating agent is one or more of ethylenediaminetetraacetic acid, hypozinotriacetic acid, or diethylenetriaminepentaacetic acid.
[0015] The composition exhibits an etching rate of <2 Å / min for Cu, Co, W, and Low-K.
[0016] The etching temperature of the composition is 20-60℃, and the etching time is 60s-300s.
[0017] The present invention also provides a method for preparing a TiN removal composition with good copper-cobalt-tungsten compatibility, comprising the following steps: adding the following mass fractions of solid components to liquid components and stirring evenly to obtain the TiN removal composition with good copper-cobalt-tungsten compatibility;
[0018] The composition consists of 40%-70% oxidant, 1%-5% alkaline substance, 0.1%-2% carboxylate, 0.1%-4% corrosion inhibitor, 0.1%-1% chelating agent, and the balance being water, with the sum of the mass fractions of all components being 100%.
[0019] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.
[0020] The reagents and raw materials used in this invention are all commercially available.
[0021] The beneficial effects of this invention are as follows:
[0022] (1) The composition of the present invention can quickly remove the metal hard mask TiN and has protective compatibility with other metal materials (Cu, Co and W) and Low-K materials. At the same time, the addition of corrosion inhibitors N-acetylgalactosamine and thiaclopidogrel hydrochloride can effectively block the etching of metal W and reduce the etching rate of W by the composition. The addition of corrosion inhibitors such as benzotriazole or methylbenzotriazole can reduce the etching rate of Cu and Co to a limited extent. The etching rate of TiN by the composition of the present invention is >200 Å / min, while the etching rate of W, Cu, Co and Low-K is <2 Å / min.
[0023] (2) Because the chelating agent can react with Cu 2+ Chelation, making Cu 2+ It loses its ability to catalyze the decomposition of H2O2, so the lifespan of the solution can be extended by adding a chelating agent, which is greater than 40 hours. Attached Figure Description
[0024] Figure 1 Example 1: SEM image of silicon wafer before etching.
[0025] Figure 2 Example 1: SEM image of a silicon wafer after etching. Detailed Implementation
[0026] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.
[0027] The abbreviations used in the examples are as follows: copper (Cu), tungsten (W), cobalt (Co), titanium nitride (TiN), low-dielectric material (Low-K), hydrogen peroxide (H2O2), monoethanolamine (MEA), triethanolamine (TEA), diethylene glycolamine (DGA), tetramethylammonium hydroxide (TMAH), N-acetylgalactosamine (GalNAc), thiaclopidogrel hydrochloride (THCl), benzotriazole (BTA), methylbenzotriazole (m-BTA), ethylenediaminetetraacetic acid (EDTA), and nitrotriacetic acid (NTA).
[0028] Preparation of a TiN removal composition with good copper-cobalt-tungsten compatibility: The types of oxidants, alkaline substances, carboxylates, corrosion inhibitors, and chelating agents in Examples 1-16 and Comparative Examples 1-6 are listed in Table 1, and the contents of each component are listed in Table 2. The water in the composition is ultrapure water, and the balance is made up with ultrapure water.
[0029] Table 1. Component types of the compositions in Examples 1-16 and Comparative Examples 1-6
[0030]
[0031] Table 2 Contents of each raw material component in the compositions of Examples 1-16 and Comparative Examples 1-6
[0032]
[0033] Preparation before etching: Cut Cu, W, Co, TiN and Low-K silicon wafers into 2cm*2cm pieces, pretreat them at room temperature with 200:1 DHF for 30s to remove surface oxide layers or stains, then rinse with deionized water and dry with nitrogen.
[0034] Etching experiment: The pretreated test sample was treated with a TiN etching cleaning solution at 50°C for 300s, then rinsed with deionized water and dried with nitrogen.
[0035] Method for measuring etching rate (Å / min): The thickness of the sample before and after etching was measured separately. The thickness of the metal sample was measured using a four-point probe instrument, and the thickness of the non-metal sample was measured using an optical ellipsometer.
[0036] Method for measuring service life: The composition of the TiN etching cleaning solution was heated at 50°C, and the TiN etching rate was measured every 2 hours. The time it took for the TiN etching rate to decrease by 10% was recorded as the service life of the solution. Etching data are shown in Table 3.
[0037] Table 3. Etching rates (Å / min) and lifetimes of Examples 1-16 and Comparative Examples 1-6
[0038]
[0039] As can be seen from the data in Table 3, in Examples 1-16, the etching rate of TiN was >200 Å / min, while the etching rates of W, Cu, Co, and Low-K were <2 Å / min, and the lifetimes of all were greater than 40 h; combined with Figure 1 and Figure 2 As can be seen, TiN on the silicon wafer was successfully etched, and the surface of the etched silicon wafer was smooth and flat. These results demonstrate that the composition provided by this invention can rapidly remove TiN and exhibits excellent protection compatibility with Cu, W, Co, and Low-K materials.
[0040] As can be seen from the data of Comparative Example 1 and the Examples, the addition of carboxylate triammonium citrate or ammonium lactate can effectively promote the etching rate of TiN, which will facilitate the rapid removal of TiN and improve the efficiency of the solution.
[0041] As can be seen from the data in Comparative Example 4, without the addition of corrosion inhibitors N-acetylgalactosamine (GalNAc) and thiaclopidogrel hydrochloride (THCl), the etching rate of W can reach 852 Å / min. This is because metallic W is easily oxidized by H2O2, forming an oxide of a certain thickness on its surface. The tungsten oxide reacts with alkaline substances to form water-soluble ammonium tungstate, as shown in the following reaction formula:
[0042] W + 3H₂O₂ → WO₃ + 3H₂O (1)
[0043] WO3 + H2O → H2WO4(2)
[0044] R-NH2+ H2O→R-NH3OH(3)
[0045] 2R-NH3OH + H2WO4→ (R-NH3)2WO4+ 2H2O (4)
[0046] Therefore, blocking one of the pathways of reaction (1-4) will help suppress the etching of metal W.
[0047] As can be seen from the data in Table 3, the addition of N-acetylgalactosamine or ticlopidine hydrochloride effectively reduces the etching rate of W by the composition, and the simultaneous addition of N-acetylgalactosamine and ticlopidine hydrochloride further reduces the etching rate of W by the composition, ultimately making the etching rate of W < 2 Å / min. This is because N-acetylgalactosamine interacts with the surface of WO3, inhibiting the combination of WO3 and H2O, thus inhibiting the reaction (2) and reducing the etching rate of W by the solution. However, since the system contains 60% of 30% H2O2, a large amount of oxidant will rapidly oxidize W to form WO3. The surface interaction ability of N-acetylgalactosamine and WO3 is limited. When N-acetylgalactosamine and ticlopidine hydrochloride coexist, ticlopidine hydrochloride will make the surface of WO3 negatively charged, which will inhibit the reaction of alkaline substances attacking to form soluble ammonium tungstate salt.
[0048] The data in Table 3 show that adding benzotriazole or methylbenzotriazole will reduce the etching rate of Cu and Co to a limited extent. Adding chelating agents EDTA or NTA will extend the service life of the etching solution, because the trace amounts of Cu remaining in the solution... 2+ It will accelerate the decomposition of H2O2; the chelating agent can react with Cu. 2+ Chelation causes it to lose its ability to catalyze the decomposition of H2O2, so the lifespan of the composition with added chelating agent is much longer than that of the composition without added chelating agent.
[0049] The foregoing descriptions of the embodiments and preferred embodiments should be considered illustrative and not limiting of the invention as defined in the claims. It will be readily understood that many variations and combinations of the features set forth above can be utilized without departing from the invention as set forth in the claims. Such variations are not considered to depart from the spirit and scope of the invention, and all such variations are intended to be included within the scope of the claims.
Claims
1. A TiN removal composition with good copper-cobalt-tungsten compatibility, characterized in that, It comprises the following components by mass fraction: 40%-70% oxidant, 1%-5% alkaline substance, 0.1%-2% carboxylate, 0.1%-4% corrosion inhibitor, 0.1%-1% chelating agent, and the balance being water, with the sum of the mass fractions of each component being 100%. The corrosion inhibitors include corrosion inhibitor 1, corrosion inhibitor 2, and corrosion inhibitor 3; corrosion inhibitor 1 is N-acetylgalactosamine; corrosion inhibitor 2 is ticlopidine hydrochloride; and corrosion inhibitor 3 is one or more of benzotriazole, methylbenzotriazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, benzimidazole, 2-mercapto-1-methylimidazole, mercapto-benzothiazole, or 1-phenyl-5-mercaptotetrazole.
2. The TiN removal composition with good copper-cobalt-tungsten compatibility as described in claim 1, characterized in that, The oxidant is one or more of hydrogen peroxide, ammonium persulfate, urea peroxide, or peracetic acid.
3. The TiN removal composition with good copper-cobalt-tungsten compatibility as described in claim 1, characterized in that, The alkaline substance is one or more of monoethanolamine, triethanolamine, diethylene glycolamine, tetramethylammonium hydroxide, ammonium hydroxide, or triethylamine.
4. The TiN removal composition with good copper-cobalt-tungsten compatibility as described in claim 1, characterized in that, The carboxylate is one or more of ammonium formate, ammonium acetate, ammonium oxalate, ammonium lactate, ammonium tartrate, or triammonium citrate.
5. The TiN removal composition with good copper-cobalt-tungsten compatibility as described in claim 1, characterized in that, The chelating agent is one or more of ethylenediaminetetraacetic acid, hypozinotriacetic acid, or diethylenetriaminepentaacetic acid.
6. The TiN removal composition with good copper-cobalt-tungsten compatibility as described in claim 1, characterized in that, The composition exhibits an etching rate of <2 Å / min for Cu, Co, W, and Low-K.
7. The TiN removal composition with good copper-cobalt-tungsten compatibility as described in claim 1, characterized in that, The etching temperature of the composition is 20-60℃, and the etching time is 60s-300s.
8. A method for preparing a TiN removal composition with good copper-cobalt-tungsten compatibility, characterized in that, Includes the following steps: The following mass fractions of solid components are added to the liquid component and stirred evenly to obtain the TiN removal composition with good copper-cobalt-tungsten compatibility; The composition consists of 40%-70% oxidant, 1%-5% alkaline substance, 0.1%-2% carboxylate, 0.1%-4% corrosion inhibitor, 0.1%-1% chelating agent, and the balance being water, with the sum of the mass fractions of all components being 100%. The corrosion inhibitors include corrosion inhibitor 1, corrosion inhibitor 2, and corrosion inhibitor 3; corrosion inhibitor 1 is N-acetylgalactosamine; corrosion inhibitor 2 is ticlopidine hydrochloride; and corrosion inhibitor 3 is one or more of benzotriazole, methylbenzotriazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, benzimidazole, 2-mercapto-1-methylimidazole, mercapto-benzothiazole, or 1-phenyl-5-mercaptotetrazole.