Etching composition

Abstract

The present disclosure relates to etching compositions that are useful for selectively removing tantalum (Ta) and / or tantalum nitride (TaN) from semiconductor substrates, for example, as an intermediate step in a multi-step semiconductor manufacturing process.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 574,279, filed Oct. 19, 2017, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to compositions and methods for selectively etching tantalum and / or tantalum nitride in the presence of other exposed or underlying materials such as metal conductors (e.g., copper), barrier materials, insulator materials (e.g., low - k dielectric materials).

Background Art

[0003] In the semiconductor industry, the reduction in the dimensions and the increase in the density of electronic circuits and components in microelectronic devices, silicon chips, liquid crystal displays, MEMS (Micro - Electro - Mechanical Systems), printed wiring boards, etc. are advancing rapidly. The integrated circuits among them have a layer structure or a stacked structure, the thickness of the insulating layer between each circuit layer continues to decrease, and the feature sizes are getting smaller and smaller. As the feature sizes are reduced, the patterns become smaller, and the performance parameters of the devices have become more stringent and stronger. As a result, various problems that were previously acceptable have become unacceptable or have become increasingly problematic due to the reduction in the feature sizes.

[0004] In the fabrication of highly integrated circuits, both high - k and low - k insulators, as well as combined barrier layer materials, have been used to minimize problems associated with increasing density and to optimize performance.

[0005] Tantalum (Ta) and tantalum nitride (TaN) are used in semiconductor devices, liquid crystal displays, MEMS (microelectromechanical systems), printed wiring boards, etc., as well as in ground layers and cap layers for noble metals, aluminum (Al), and copper (Cu) wiring. In semiconductor devices, it can be used as a barrier metal, hard mask, or gate material.

[0006] In the construction of devices for such applications, it is often necessary to etch Ta and TaN. In various types of uses and device environments of Ta and TaN, when these two materials are etched, other layers are either in contact or exposed simultaneously. High-precision selective etching of Ta and TaN in the presence of such other materials (e.g., metal conductors, dielectrics, and hard marks) is required for device yield and long life. The etching process of Ta and TaN may be a plasma etching process. However, using a plasma etching process on a Ta or TaN layer may cause damage to either or both of the gate insulating layer and the semiconductor substrate. In addition, the etching process may remove a part of the semiconductor substrate by etching the gate insulating layer exposed by the gate electrode. The electrical characteristics of the transistor may be adversely affected. To avoid such damage caused by etching, additional protective device manufacturing processes may be used, but they are accompanied by significant costs.

[0007] Wet etching methods for Ta and TaN are known. Such methods may involve the use of etching solutions combined with other reagents. However, the selectivity with respect to silicon-based dielectrics and metals (e.g., Cu) is not sufficient, and other exposed metals in the device may also be corroded or etched. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Therefore, an etching solution is required that has a high etching rate for Ta or TaN, but has a low etching rate and corrosion rate during the etching process for other semiconductor materials that are exposed or in contact with Ta or TaN.

[0009] The present disclosure relates to compositions and processes for selectively etching Ta and / or TaN with respect to metal conductor layers, hard mask layers, and low-k dielectric layers present in semiconductor devices. More particularly, the present disclosure relates to compositions and processes for selectively etching Ta and / or TaN with respect to copper and low-k dielectric layers.

Means for Solving the Problems

[0010] In one aspect, the present disclosure relates to an etching composition comprising: a) hydrofluoric acid; b) at least one first solvent containing a carboxylic acid; c) at least one oxidizing agent; and d) at least one complexing agent selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids.

[0011] In another aspect, the present disclosure relates to an etching composition comprising: a) hydrofluoric acid; b) at least one first solvent containing a carboxylic acid; and c) at least one complexing agent selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids.

[0012] In another aspect, the present disclosure relates to a method comprising contacting a semiconductor substrate containing Ta and / or TaN with the etching composition described herein to remove Ta and / or TaN.

[0013] In yet another aspect, the present disclosure relates to an article formed by the method described above, wherein the article is a semiconductor device (e.g., an integrated circuit).

Embodiments for Carrying Out the Invention

[0014] Unless otherwise defined in this specification, all percentages expressed are to be understood as weight percentages relative to the total weight of the composition. Unless otherwise specified, the ambient temperature is defined as being from about 16 degrees Celsius to about 27 degrees Celsius (°C).

[0015] Generally, the present disclosure relates to an etching composition (e.g., an etching composition for selectively removing tantalum and / or tantalum nitride) comprising a) hydrofluoric acid (HF); b) at least one first solvent that is a carboxylic acid; c) at least one oxidizing agent; and d) at least one complexing agent selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids.

[0016] In some embodiments, the hydrofluoric acid is present in an amount of about 0.1 wt% or more (e.g., about 0.2 wt% or more, about 0.4 wt% or more, about 0.5 wt% or more, about 0.6 wt% or more, about 0.8 wt% or more, about 1 wt% or more, about 1.2 wt% or more, about 1.4 wt% or more, or about 1.5 wt% or more) to about 5 wt% or less (e.g., about 4.5 wt% or less, about 4 wt% or less, about 3.5 wt% or less, about 3 wt% or less, about 2.5 wt% or less, or about 2 wt% or less) of the etching composition of the present disclosure. Without being bound by theory, it is believed that hydrofluoric acid can promote and improve the removal of Ta and / or TaN on the semiconductor substrate during the etching process.

[0017] The etching composition of the present disclosure may contain any oxidizing agent suitable for use in microelectronic device applications, if desired. Examples of suitable oxidizing agents include, but are not limited to, oxidizing acids or their salts (e.g., nitric acid, permanganic acid, or potassium permanganate), peroxides (e.g., hydrogen peroxide, dialkyl peroxide, urea hydrogen peroxide), persulfonic acids (e.g., hexafluoropropane persulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, or p-toluenesulfonic acid) and their salts, ozone, percarbonic acids (e.g., peracetic acid) and their salts, perphosphoric acid and its salts, persulfuric acid and its salts (e.g., ammonium persulfate or tetramethylammonium persulfate), perchloric acid and its salts (e.g., ammonium perchlorate, sodium perchlorate, or tetramethylammonium perchlorate), and periodic acid and its salts (e.g., periodic acid, ammonium periodate, or tetramethylammonium periodate). These oxidizing agents may be used alone or in combination.

[0018] In some embodiments, the oxidizing agent may be from about 0.01 wt% or more (e.g., about 0.02 wt% or more, about 0.04 wt% or more, about 0.05 wt% or more, about 0.06 wt% or more, about 0.08 wt% or more, about 0.1 wt% or more, about 0.15 wt% or more, or about 0.2 wt% or more) to about 0.5 wt% or less (e.g., about 0.45 wt% or less, about 0.4 wt% or less, about 0.35 wt% or less, about 0.3 wt% or less, about 0.25 wt% or less, or about 0.2 wt% or less) of the etching composition of the present disclosure. Without being bound by theory, it is believed that the oxidizing agent can promote and improve the removal of Ta and / or TaN on the semiconductor substrate.

[0019] In some embodiments, the etching composition of the present disclosure may exclude an oxidizing agent (e.g., nitric acid). In such embodiments, the etching composition may still be capable of selectively etching Ta and / or TaN with respect to other materials (e.g., metal conductor layers, hard mask layers, and low-k dielectric layers) in a patterned semiconductor substrate (e.g., a patterned wafer).

[0020] Generally, the etching composition of the present disclosure may include any suitable complexing agent. In some embodiments, the complexing agent can be selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids. As used herein, the term "polycarboxylic acid" means a compound containing two or more (e.g., 2, 3, or 4) carboxyl groups (COOH). Examples of suitable polycarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid. As used herein, the term "hydroxycarboxylic acid" means a compound containing at least one (e.g., 2, 3, or 4) hydroxyl group (OH) and at least one (e.g., 2, 3, or 4) carboxyl group (COOH). Examples of suitable hydroxycarboxylic acids include citric acid and 2-hydroxybenzoic acid. In some embodiments, the polycarboxylic acid does not contain a hydroxyl group. In some embodiments, the hydroxycarboxylic acid contains only one hydroxyl group.

[0021] In some embodiments, the complexing agent may be from about 0.1 wt% or more (e.g., about 0.2 wt% or more, about 0.4 wt% or more, about 0.5 wt% or more, about 0.6 wt% or more, about 0.8 wt% or more, about 1 wt% or more, about 1.5 wt% or more, about 2 wt% or more, about 2.5 wt% or more, or about 5 wt% or more) to about 10 wt% or less (e.g., about 9.5 wt% or less, about 9 wt% or less, about 8.5 wt% or less, about 8 wt% or less, about 7.5 wt% or less, about 7 wt% or less, about 6.5 wt% or less, about 6 wt% or less, about 5.5 wt% or less, or about 5 wt% or less) of the etching composition of the present disclosure. Without being bound by theory, it is believed that the complexing agent can promote and improve the removal of Ta and / or TaN on the semiconductor substrate during the etching process, while inhibiting the removal of Cu exposed to the etching composition.

[0022] Generally, the etching composition of the present disclosure may include at least one (e.g., 2, 3, or 4) solvent. In some embodiments, the etching composition may include a first solvent that is a carboxylic acid. In such embodiments, the first solvent may be a carboxylic acid of the formula: R-COOH, where R is H or C1-C6 alkyl. Examples of such carboxylic acids include formic acid, acetic acid, trifluoroacetic acid, propionic acid, lactic acid, butyric acid, valeric acid, and caproic acid.

[0023] In some embodiments, the first solvent may be the main component of the etching composition of the present disclosure. For example, the first solvent may be from about 70 wt% or more (e.g., about 75 wt% or more, about 80 wt% or more, about 85 wt% or more, about 90 wt% or more, or about 95 wt% or more) to about 99.9 wt% or less (e.g., about 99 wt% or less, about 98 wt% or less, about 97 wt% or less, about 96 wt% or less, about 95 wt% or less, about 90 wt% or less, or about 85 wt% or less) of the etching composition. Without being bound by theory, it is believed that the carboxylic acid used as the first solvent described herein can promote and improve the removal of Ta and / or TaN on the semiconductor substrate during the etching process.

[0024] In some embodiments, the etching composition of the present disclosure may include two or more (e.g., 2, 3, or 4) solvents. For example, the etching composition may include at least one second solvent selected from the group consisting of organic solvents (not carboxylic acids) and inorganic solvents. Examples of suitable inorganic solvents include water and aqueous solutions. In some embodiments, the water is deionized ultrapure water, contains no organic contaminants, and has a minimum resistivity of about 4 to about 17 megohms, or at least about 17 megohms. In some embodiments, the at least one second solvent (e.g., water) is present in an amount of about 0.01 wt% or more (e.g., about 0.05 wt% or more, about 0.1 wt% or more, about 0.5 wt% or more, about 1 wt% or more, about 2 wt% or more, about 3 wt% or more, about 4 wt% or more, or about 5 wt% or more) to about 10 wt% or less (e.g., about 9 wt% or less, about 8 wt% or less, about 7 wt% or less, about 6 wt% or less, about 5 wt% or less, or about 4 wt% or less) of the etching composition. Without being bound by theory, if the amount of water exceeds 10 wt% of the composition, it is believed that during the etching process, it may have an adverse effect on the etching rate of Ta and / or TaN and reduce their removal. On the other hand, without being bound by theory, if the amount of water is less than 0.01 wt%, it is believed that the oxidation ability of the composition will be reduced, thereby reducing the etching rate of Ta and / or TaN.

[0025] In some embodiments, the second solvent may be an organic solvent that is not a carboxylic acid. For example, the organic solvent may be a hydrophobic organic solvent having a partition coefficient (logP) greater than 0 (e.g., about 0.1 or more, about 0.2 or more, about 0.3 or more, about 0.5 or more, about 1 or more, about 1.5 or more, or about 2 or more) and about 5 or less. As used herein, the partition coefficient logP is obtained from a two-phase system of n-octanol and water. In some embodiments, the organic solvent may be an alcohol or an ether. The ether may be an alkylene glycol ether (e.g., a dialkylene glycol ether, a trialkylene glycol ether, and a tetraalkylene glycol ether). Examples of such organic solvents include benzyl alcohol, diethylene glycol butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl ether, tetraethylene glycol dimethyl ether, and dipropylene glycol dimethyl ether. Without being bound by theory, it is believed that by using a hydrophobic organic solvent, Cu removal can be inhibited without reducing Ta or TaN removal during the etching process.

[0026] In some embodiments, the at least one second solvent (e.g., an organic solvent) is present in an amount of about 0.1 wt% or more (e.g., about 0.2 wt% or more, about 0.4 wt% or more, about 0.5 wt% or more, about 0.6 wt% or more, about 0.8 wt% or more, about 1 wt% or more, about 1.5 wt% or more, about 2 wt% or more, about 2.5 wt% or more, or about 5 wt% or more) to about 20 wt% or less (e.g., about 15 wt% or less, about 10 wt% or less, about 8 wt% or less, about 6 wt% or less, about 5 wt% or less, or about 4 wt% or less) of the etching composition of the present disclosure.

[0027] In some embodiments, the etching composition of the present disclosure may further include at least one (e.g., 2, 3, or 4) hexafluorosilicate compound. Examples of suitable hexafluorosilicate compounds include hexafluorosilicic acid (H2SiF6) and its salts. Specific examples of hexafluorosilicate compounds include H2SiF6, Na2SiF6, K2SiF6, and (NH4)2SiF6. In some embodiments, the hexafluorosilicate compound is present in an amount of about 0.1 wt% or more (e.g., about 0.2 wt% or more, about 0.4 wt% or more, about 0.5 wt% or more, about 0.6 wt% or more, about 0.8 wt% or more, about 1 wt% or more, about 1.5 wt% or more, about 2 wt% or more, or about 2.5 wt% or more) to about 5 wt% or less (e.g., about 4.5 wt% or less, about 4 wt% or less, about 3.5 wt% or less, about 3 wt% or less, about 2.5 wt% or less, or about 2 wt% or less) of the etching composition. Without being bound by theory, the hexafluorosilicate compounds described above are thought to promote and improve the removal of Ta and / or TaN on the semiconductor substrate during the etching process, while simultaneously inhibiting the removal of the dielectric material (SiO2) exposed to the etching composition.

[0028] In some embodiments, the etching composition of the present disclosure may further include at least one (e.g., 2, 3, or 4) sulfonic acid. Examples of suitable sulfonic acids include p-toluenesulfonic acid, methanesulfonic acid, or dodecylbenzenesulfonic acid. In some embodiments, the sulfonic acid is present in an amount of about 0.1 wt% or more (e.g., about 0.2 wt% or more, about 0.4 wt% or more, about 0.5 wt% or more, about 0.6 wt% or more, about 0.8 wt% or more, about 1 wt% or more, about 1.5 wt% or more, about 2 wt% or more, about 2.5 wt% or more, or about 5 wt% or more) to about 10 wt% or less (e.g., about 9 wt% or less, about 8 wt% or less, about 7 wt% or less, about 6 wt% or less, about 5 wt% or less, about 4.5 wt% or less, about 4 wt% or less, about 3.5 wt% or less, about 3 wt% or less, about 2.5 wt% or less, or about 2 wt% or less) of the etching composition. Without being bound by theory, it is believed that the sulfonic acid described above can promote and improve the removal of Ta and / or TaN on the semiconductor substrate during the etching process.

[0029] In some embodiments, the etching composition of the present disclosure may further include at least one (e.g., 2, 3, or 4) surfactant. Examples of suitable surfactants include nonionic surfactants. In some embodiments, the surfactant is present in an amount of about 0.0001 wt% or more (e.g., about 0.001 wt% or more, about 0.01 wt% or more, about 0.1 wt% or more, about 0.2 wt% or more, about 0.3 wt% or more, about 0.4 wt% or more, or about 0.5 wt% or more) to about 1 wt% or less (e.g., about 0.9 wt% or less, about 0.8 wt% or less, about 0.7 wt% or less, about 0.6 wt% or less, or about 0.5 wt% or less) of the etching composition. Without being bound by theory, it is believed that the surfactant can promote the uniformity of the etching composition and assist in dissolving components (e.g., sulfonic acid) in the polycarboxylic acid solvent.

[0030] In some embodiments, the etching composition of the present disclosure may have a pH of about 1 or less (e.g., about 0.9 or less, about 0.8 or less, about 0.7 or less, about 0.6 or less, or about 0.5 or less) and / or about 0 or more (e.g., about 0.1 or more, about 0.2 or more, about 0.3 or more, about 0.4 or more, or about 0.5 or more). Without being bound by theory, an etching composition having a pH higher than 1 may not have sufficient etching rates for Ta and / or T aN because sufficiently high acidity is required for the removal of these materials, and an etching composition having a pH lower than 0 is considered to be able to decompose certain components in the composition due to strong acidity.

[0031] In addition, in some embodiments, the etching composition of the present disclosure may contain additives such as a pH adjuster, a corrosion inhibitor, a further surfactant, a further organic solvent, a biocide, and an antifoaming agent as components that may be included as desired. Examples of suitable antifoaming agents include polysiloxane antifoaming agents (e.g., polydimethylsiloxane), polyethylene glycol methyl ether polymers, ethylene oxide / propylene oxide copolymers, and glycidyl ether-capped acetylene-based diol ethoxylates (such as those described in U.S. Patent No. 6,717,019, which is incorporated herein by reference). Examples of suitable surfactants may be cationic, anionic, nonionic, or amphoteric.

[0032] Generally, the etching composition of the present disclosure may have a relatively high Ta / Cu and / or TaN / Cu etching selectivity (i.e., a high ratio of Ta etching rate to Cu etching rate and / or a high ratio of TaN etching rate to Cu etching rate). In some embodiments, the etching composition may have a Ta / Cu and / or TaN / Cu etching selectivity of about 2 or more (e.g., about 3 or more, about 4 or more, about 5 or more, about 6 or more, about 7 or more, about 8 or more, about 9 or more, about 10 or more, about 15 or more, about 20 or more, about 30 or more, about 40 or more, or about 50 or more) and / or about 500 or less (e.g., about 100 or less).

[0033] Generally, the etching compositions of the present disclosure can have a relatively high Ta / dielectric material (e.g., SiO2 or low-k material) and / or TaN / dielectric material etching selectivity (i.e., a high ratio of Ta etching rate to dielectric material etching rate and / or a high ratio of TaN etching rate to dielectric material etching rate). In some embodiments, the etching composition can have a Ta / dielectric material and / or TaN / dielectric material etching selectivity of about 2 or more (e.g., about 3 or more, about 4 or more, about 5 or more, about 6 or more, about 7 or more, about 8 or more, about 9 or more, about 10 or more, about 15 or more, about 20 or more, about 30 or more, about 40 or more, or about 50 or more) and / or about 500 or less (e.g., about 100 or less).

[0034] In some embodiments, the etching compositions of the present disclosure may specifically exclude one or more of the additive components, in any combination if there are two or more. Such components are selected from the group consisting of oxidizing agents (such as those described herein), polymers, oxygen scavengers, quaternary ammonium salts (including quaternary ammonium hydroxides), amines, alkaline bases (such as NaOH, KOH, and LiOH), surfactants other than defoamers, defoamers, fluoride-containing compounds, abrasives, silicates, hydroxycarboxylic acids containing three or more hydroxyl groups, carboxylic acids and polycarboxylic acids without amino groups, silanes (e.g., alkoxysilanes), cyclic compounds (e.g., azoles (such as diazoles, triazoles, or tetrazoles), triazines, and cyclic compounds containing at least two rings such as substituted or unsubstituted naphthalene, or substituted or unsubstituted biphenyl ethers), buffers, non-azole corrosion inhibitors, and metal halides.

[0035] The etching composition of the present disclosure may be prepared by simply mixing the above components together, or may be prepared by blending two compositions in a kit. The first composition in the kit may be an aqueous solution of an oxidizing agent (e.g., nitric acid). The second composition in the kit may contain the remaining components of the etching composition of the present disclosure in a concentrated form at a predetermined ratio so that the desired etching composition of the present disclosure can be obtained by blending the two compositions.

[0036] In some embodiments, the present disclosure relates to a method of etching a semiconductor substrate containing Ta and / or TaN (e.g., a feature containing Ta and / or TaN). The method includes contacting a semiconductor substrate containing Ta and / or TaN with the etching composition of the present disclosure to remove Ta and / or TaN. The method may further include rinsing the semiconductor substrate with a rinse solvent after the contacting step and / or drying the semiconductor substrate after the rinsing step. In some embodiments, the method does not substantially remove Cu or a dielectric material (e.g., SiO2) in the semiconductor substrate. For example, the method does not remove more than about 5 wt% (e.g., more than about 3 wt% or more than about 1 wt%) of the Cu or dielectric material in the semiconductor substrate.

[0037] In some embodiments, the etching method is as follows: (A) providing a semiconductor substrate containing Ta and / or TaN; (B) contacting the semiconductor substrate with the etching composition described herein; (C) rinsing the semiconductor substrate with one or more suitable rinse solvents; and (D) optionally, drying the semiconductor substrate (e.g., by removing the rinse solvent and by any suitable means that does not impair the integrity of the semiconductor substrate), including.

[0038] The semiconductor substrate containing Ta and / or TaN to be etched by this method may contain organic and organometallic residues, and may further contain various metal oxides that can also be removed during the etching process.

[0039] Semiconductor substrates (e.g., wafers) are typically constructed from silicon, silicon germanium, Group III-V compounds such as GaAs, or any combination thereof. The semiconductor substrate may further contain exposed integrated circuit structures such as interconnect features (e.g., metal lines and dielectric materials). Metals and metal alloys used for interconnect features include, but are not limited to, aluminum, aluminum alloyed with copper, copper, titanium, tantalum, cobalt, silicon, titanium nitride, tantalum nitride, and tungsten. The semiconductor substrate may contain layers of interlayer dielectrics, silicon oxide, silicon nitride, silicon carbide, titanium oxide, and carbon-doped silicon oxide.

[0040] Contact between the semiconductor substrate and the etchant composition may be made by any suitable method, including placing the etchant composition in a tank and immersing and / or submerging the semiconductor substrate in the etchant composition, spraying the etchant composition onto the semiconductor substrate, flowing the etchant composition over the semiconductor substrate, or any combination thereof.

[0041] The etching composition of the present disclosure may be used at temperatures up to substantially about 85°C (e.g., about 20°C to about 80°C, about 55°C to about 65°C, or about 60°C to about 65°C). The etching rate of Ta and / or TaN increases with temperature within this range, and thus the process at higher temperatures can be carried out in a shorter time. Conversely, etching at lower temperatures typically requires a longer etching time.

[0042] The etching time may vary widely depending on a particular etching method, thickness, and temperature used. When etching is performed in a dip batch type process, a suitable time range is, for example, up to about 10 minutes (e.g., about 1 minute to about 7 minutes, about 1 minute to about 5 minutes, or about 2 minutes to about 4 minutes). The etching time in the case of single wafer processing may be in the range of about 30 seconds to about 5 minutes (e.g., about 30 seconds to about 4 minutes, about 1 minute to about 3 minutes, or about 1 minute to about 2 minutes).

[0043] In order to further improve the etching ability of the etching composition of the present disclosure, mechanical stirring means may be used. Examples of suitable stirring means include circulation of the etching composition on the substrate, flow or spraying of the etching composition on the substrate, and ultrasonic or high frequency ultrasonic stirring during the etching process. The orientation of the semiconductor substrate with respect to the ground surface may be at any angle. A horizontal or vertical orientation is preferred.

[0044] Following the etching, the semiconductor substrate may be rinsed for about 5 seconds to about 5 minutes with a suitable rinse solvent, with or without agitation means. Multiple rinse steps using different rinse solvents may be used. Examples of suitable rinse solvents include, but are not limited to, deionized (DI) water, methanol, ethanol, isopropyl alcohol, N-methylpyrrolidinone, gamma-butyrolactone, dimethyl sulfoxide, ethyl lactate, and propylene glycol monomethyl ether acetate. As another option, or in addition, an aqueous rinse solution with pH > 8 (such as a diluted aqueous ammonium hydroxide solution) may be used. Examples of rinse solvents include, but are not limited to, diluted aqueous ammonium hydroxide solution, DI water, methanol, ethanol, and isopropyl alcohol. The application of the rinse solvent may be performed using means similar to those used for the application of the etching composition described herein. The etching composition may be removed from the semiconductor substrate prior to the start of the rinse step, or may still be in contact with the semiconductor substrate at the start of the rinse step. In some embodiments, the temperature used in the rinse step is 16°C to 27°C.

[0045] Optionally, the semiconductor substrate is dried after the rinse step. Any suitable drying means known in the art may be used. Examples of suitable drying means include spin drying, flowing a drying gas over the entire semiconductor substrate, or heating the semiconductor substrate using heating means such as a hot plate or an infrared lamp, Marangoni drying, Rotagoni drying, IPA drying, or any combination thereof. The drying time varies depending on the specific method used, but is typically on the order of 30 seconds to several minutes.

[0046] In some embodiments, the etching method described herein further includes forming a semiconductor device (e.g., an integrated circuit device such as a semiconductor chip) from the semiconductor substrate obtained by the method described above.

[0047] The present disclosure will be described in more detail with reference to the following examples, which are for illustrative purposes only and should not be construed as limiting the scope of the present disclosure.

Example

[0048] All of the listed percentages are by weight (wt%) unless otherwise specified. In the tests, controlled stirring at 300 rpm with a 1-inch stir bar was performed unless otherwise specified.

[0049] General Procedure 1 Blending of Formulations Samples of the etching composition were prepared by adding the remaining components of the formulation to the calculated amount of solvent with stirring. After a homogeneous solution was obtained, additives that may be included as desired were added if used.

[0050] General Procedure 2 Materials and Methods Blanket film etching rate measurements on the film were performed using commercially available unpatterned 300 mm diameter wafers diced into 0.5 × 0.5 inch test coupons for evaluation. The main blanket film materials used in the tests included 1) a low-k film (k value 2.55) deposited on a silicon substrate with a thickness of about 1000 Å, 2) a non-alloyed copper metal film deposited on a silicon substrate with a thickness of about 1000 Å, 3) a tantalum film deposited on 1000 Å of SiO2 on a silicon substrate with a thickness of about 250 Å, 4) a tantalum nitride film deposited on 1000 Å of SiO2 on a silicon substrate with a thickness of about 250 Å, 5) a blanket CVD SiO2 film and / or a thermal oxide (SiO2) film deposited on a silicon substrate with a thickness of about 1000 Å.

[0051] The blanket film test coupons were measured for thickness before and after treatment to determine the etching rate of the blanket film. For copper and tantalum metal blanket films, the film thickness was measured by sheet resistance using a Keithley Model 8009 resistivity test fixture four-point probe. For TaN, SiO2, and low-k films, the film thickness was measured before and after treatment by ellipsometry using a Woollam VASE.

[0052] The patterned test coupons were evaluated for etching and material compatibility in the test solution prepared according to General Procedure 1 according to the procedure described in General Procedure 3.

[0053] The patterned test coupon Cu / Ta(3nm) / TaN(3nm) / ILD was evaluated for material compatibility and / or etching responsiveness. Next, the post-treatment test coupon was subjected to evaluation by a scanning electron microscope (SEM). The SEM image from the post-treatment coupon was compared with a pre-taken set of pre-treatment SEM images to evaluate the material compatibility and etching responsiveness of each test formulation with the patterned test device features.

[0054] General Procedure 3 Etching Evaluation by Beaker Test All blanket film etching tests were conducted at room temperature (21 - 23 °C) with continuous stirring at 250 rpm by placing 200 g of the sample solution in a 600 mL glass beaker and leaving it covered with Parafilm® to minimize loss due to evaporation. All blanket test coupons with a blanket metal film or a dielectric film on one side exposed to the sample solution were diced by a diamond scriber to a 0.5 x 0.5 inch square test coupon size for beaker scale testing. Each individual test coupon was fixed in place using a single 4 - inch long locking plastic tweezers clip. The test coupon with one edge fixed by the locking plastic tweezers clip was suspended into a 600 mL glass beaker and immersed in 200 g of the test solution while simultaneously stirring the solution continuously at room temperature and 250 rpm. Immediately after each sample coupon was placed in the stirred solution, the top of the 600 mL glass beaker was covered with Parafilm® and resealed. The test coupon was held stationary in the stirred solution until the processing time (described in General Procedure 3A) elapsed. After the processing time in the test solution had elapsed, the sample coupon was immediately removed from the 600 mL glass beaker and rinsed according to General Procedure 3A. After the final DI rinse step, all test coupons were subjected to a blow - off step with filtered nitrogen gas using a hand - held nitrogen gas blower, thereby forcibly removing all remaining trace amounts of DI water to obtain the final dry samples for test measurement.

[0055] General Procedure 3A (Blanket Test Coupons) Immediately after a 10 - minute processing time according to General Procedure 3, the coupon was immersed in 1000 mL of ultra - high purity deionized (DI) water at an overflow rate of approximately 1 liter / minute at 20 °C for 30 seconds, followed by an additional 30 seconds of immersion with gentle stirring. The processing was completed according to General Procedure 3.

[0056] General Procedure 3B (Patterned Test Coupons) Immediately after a processing time of 2.5 to 3 minutes (varying according to the experiment), the patterned test coupon was immersed in isopropyl alcohol (IPA) or ultrapure deionized water at 20 °C for 20 seconds with gentle stirring for post-treatment rinsing. The patterned test coupon was taken out from the IPA or DI water and immediately placed in a 1 wt% citric acid solution for 30 seconds with gentle stirring, followed by a final 30-second rinse with a 1000 mL DI water overflow rinse. The treatment was completed according to General Procedure 3.

[0057] Example 1 Formulation Examples 1 to 4 (FE-1 to FE-4) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 1.

[0058] [Table 1]

[0059] As shown in Table 1, FE-1 (chelating agent-free) and FE-2 (containing citric acid as a chelating agent) exhibited relatively high Cu etching rates and relatively low TaN / Cu etching selectivities (i.e., the ratio of the etching rates of TaN and Cu). In addition, FE-4 (containing benzoguanamine as a chelating agent) did not exhibit a TaN etching rate. In contrast, FE-3 (containing oxalic acid (a polycarboxylic acid) as a chelating agent) surprisingly exhibited a high TaN etching rate and a low Cu etching rate, and as a result, a high TaN / Cu etching selectivity was obtained. In other words, FE-3 could effectively remove TaN during the etching process, while minimizing the removal of exposed Cu on the semiconductor substrate.

[0060] Example 2 Formulation Examples 5 to 11 (FE-5 to FE-11) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 2.

[0061]

Table 2

[0062] As shown in Table 2, FE-9 (containing glycerol as a complexing agent) and FE-10 (containing diammonium tartrate as a complexing agent) exhibited low Ta and TaN etching rates, as well as low Ta / Cu and TaN / Cu etching selectivities. In contrast, FE-5 to FE-7 (containing oxalic acid as a complexing agent), FE-8 (containing citric acid as a complexing agent), and FE-11 (containing 2-hydroxybenzoic acid as a complexing agent) surprisingly exhibited high Ta and TaN etching rates and low Cu etching rates, resulting in high Ta / Cu and TaN / Cu etching selectivities. In other words, these three formulations were able to effectively remove Ta and TaN during the etching process, while minimizing the removal of exposed Cu on the semiconductor substrate.

[0063] Example 3 Formulation Examples 12 to 16 (FE-12 to FE-16) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 3.

[0064]

Table 3

[0065] As shown in Table 3, FE-12 to FE-16 (containing a hydrophobic solvent with logP greater than 0, i.e., dipropylene glycol dimethyl ether or benzyl alcohol) exhibited low etching rates for Cu and acceptable Ta / Cu and / or TaN / Cu etching selectivities. In other words, these data suggest that hydrophobic solvents can inhibit the corrosion of Cu during the etching process.

[0066] Example 4 Formulation Examples 17 to 19 (FE-17 to FE-19) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 4.

[0067] [Table 4]

[0068] As shown in Table 4, FE-17 to FE-18 (sulfonic acid-containing) exhibited a relatively high TaN etching rate compared to FE-19 (sulfonic acid-free).

[0069] Example 5 Formulation Examples 20 to 24 (FE-20 to FE-24) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 5.

[0070] [Table 5]

[0071] As shown in Table 5, FE-20 to FE-24 (sulfonic acid-containing) exhibited a relatively high TaN etching rate, a relatively low Cu etching rate, and a relatively high TaN / Cu etching selectivity.

[0072] Example 6 Formulation Examples 25 to 27 (FE-25 to FE-27) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 6.

[0073] [Table 6]

[0074] As shown in Table 6, as the amount of benzyl alcohol increased from FE-25 to FE-27, their Cu etching rates decreased.

[0075] Example 7 Formulation Examples 28 to 34 (FE-28 to FE-34) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 7.

[0076]

Table 7

[0077] As shown in Table 7, FE-28 to FE-30, and FE-32 (each containing a solvent with a logP value less than 0) exhibited relatively low Cu etching rates, but at the same time, the TaN etching rate was also relatively low. On the other hand, FE-31 and FE-33 (each containing a solvent with a logP value greater than 0) exhibited relatively low Cu etching rates, but the TaN etching rate was relatively high, and thus, a relatively high TaN / Cu etching selectivity was obtained.

[0078] Furthermore, these results also show that FE-28 to FE-33 (each containing an alcohol solvent) exhibited a lower TaN etching rate than FE-34 (non-containing an alcohol solvent). Without being bound by theory, it is considered that the presence of alcohol may reduce the TaN etching rate of the etching composition.

[0079] Example 8 Formulation Examples 35 to 39 (FE-35 to FE-39) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 8.

[0080]

Table 8

[0081] As shown in Table 8, FE-35 to FE-37 (each containing a solvent with a logP value less than 0) exhibited relatively low TaN / Cu etching selectivity. On the other hand, FE-36 (containing a solvent with a logP value greater than 0) exhibited a relatively low Cu etching rate, but a relatively high TaN etching rate, and thus, a relatively high TaN / Cu etching selectivity was obtained. In addition, FE-38 and FE-39 (each not containing an organic solvent other than acetic acid) also exhibited relatively high TaN / Cu etching selectivity.

[0082] Example 9 Formulation Examples 40 to 43 (FE-40 to FE-43) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 9.

[0083]

Table 9

[0084] As shown in Table 9, all of FE-40 to FE-43 exhibited high Ta / Cu and TaN / Cu etching selectivities. However, all four formulations exhibited relatively high etching rates with respect to SiO2 (dielectric material). On the other hand, by including H2SiF6 in FE-42 and FE-43, their TaN etching rates were greatly improved without significantly increasing their SiO2 etching rates, resulting in an improvement in TaN / SiO2 etching selectivity.

[0085] Example 10 Formulation Examples 44 to 45 (FE-44 to FE-45) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3a. The formulations and test results are summarized in Table 10.

[0086]

Table 10

[0087] As shown in Table 10, FE-45 exhibited relatively high Ta / Cu and TaN / Cu etching selectivities. Additionally, FE-45 contained no oxidizing agent (i.e., nitric acid), yet still exhibited relatively high TaN / Cu etching selectivity.

[0088] Example 11 Formulation Examples 46 to 49 (FE-46 to FE-49) were prepared according to General Procedure 1 and evaluated according to General Procedures 2 and 3b. The formulations and test results are summarized in Table 11.

[0089]

Table 11

[0090] As shown in Table 11, FE-46 to FE-49 contained no oxidizing agent (i.e., nitric acid), yet still exhibited relatively high TaN / Cu etching selectivity and were able to remove the TaN layer of the patterned wafer.

[0091] Although the present invention has been described in detail with reference to certain specific embodiments, it is understood that modifications and changes are within the spirit and scope of the invention as described and claimed. The present disclosure includes the following embodiments. <1> a) Hydrofluoric acid; b) At least one first solvent containing a carboxylic acid; c) At least one oxidizing agent; and d) At least one complexing agent selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids, An etching composition comprising. <2> The composition according to <1>, wherein the hydrofluoric acid is present in an amount of about 0.1% to about 5% by weight of the composition. <3> The composition according to <1>, wherein at least one first solvent contains R-COOH, and R is H or C 1 ~C 6 An alkyl. <4> The composition according to <1>, wherein the at least one first solvent contains formic acid, acetic acid, trifluoroacetic acid, propionic acid, lactic acid, butyric acid, valeric acid, or caproic acid. <5> The composition according to <1>, wherein the at least one first solvent is present in an amount of about 70% to about 99.9% by weight of the composition. <6> The composition according to <1>, wherein the at least one oxidizing agent contains nitric acid, KMnO 4 、H 2 O 2 、H 5 IO 5 , or NaClO 4 . <7> The composition according to <1>, wherein the at least one oxidizing agent is present in an amount of about 0.01% to about 0.5% by weight of the composition. <8> The composition according to <1>, wherein the at least one complexing agent contains oxalic acid, citric acid, or 2-hydroxybenzoic acid. <9> The composition according to <1>, wherein the at least one complexing agent is present in an amount of about 0.1% to about 10% by weight of the composition. <10> The composition according to <1>, further comprising at least one hexafluorosilicate compound. <11> The composition according to <10>, wherein the at least one hexafluorosilicate compound contains H 2 SiF 6 , Na 2 SiF 6 、K 2 SiF 6 , or (NH 4 ) 2 SiF 6 . <12> The composition according to <10>, wherein the at least one hexafluorosilicate compound is present in an amount of about 0.1% to about 5% by weight of the composition. <13> The composition according to <1>, further comprising at least one sulfonic acid. <14> The composition according to <13>, wherein the at least one sulfonic acid contains p-toluenesulfonic acid, methanesulfonic acid, or dodecylbenzenesulfonic acid. <15> The composition according to <13>, wherein the at least one sulfonic acid is present in an amount of about 0.1% to about 10% by weight of the composition. <16> The composition according to <1> above, further comprising at least one second solvent selected from the group consisting of organic solvents and inorganic solvents. <17> The composition according to <16> above, wherein the at least one second solvent contains water. <18> The composition according to <17> above, wherein the water is present in an amount of about 0.01 wt% to about 10 wt% of the composition. <19> The composition according to <16> above, wherein the at least one second solvent contains an organic solvent having a partition coefficient (logP) greater than 0. <20> The composition according to <19> above, wherein the organic solvent contains alcohol or ether. <21> The composition according to <19> above, wherein the organic solvent contains alcohol or alkylene glycol ether. <22> The composition according to <19> above, wherein the organic solvent contains benzyl alcohol, diethylene glycol butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl ether, tetraethylene glycol dimethyl ether, or dipropylene glycol dimethyl ether. <23> The composition according to <16> above, wherein the organic solvent is present in an amount of about 0.1 wt% to about 20 wt% of the composition. <24> The composition according to <1> above, further comprising at least one surfactant. <25> The composition according to <24> above, wherein the at least one surfactant contains a nonionic surfactant. <26> The composition according to <24> above, wherein the at least one surfactant is present in an amount of about 0.0001 wt% to about 1 wt% of the composition. <27> The composition according to <1> above, having a pH of about 1 or less. <28> A method comprising contacting a semiconductor substrate containing Ta or TaN with the composition according to <1> above to remove the Ta or TaN. <29> The method according to <28> above, further comprising rinsing the semiconductor substrate with a rinse solvent after the contacting step. <30> The method according to <29> above, further comprising drying the semiconductor substrate after the rinsing step. <31> The method according to <28> above, which does not substantially remove Cu or dielectric material on the semiconductor substrate. <32> An article formed by the method according to <28> above, which is a semiconductor device. <33> The article according to <32>, wherein the semiconductor device is an integrated circuit. <34> a) hydrofluoric acid; b) at least one first solvent containing a carboxylic acid; and c) at least one complexing agent selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids An etching composition comprising

Claims

1. a) hydrofluoric acid; b) at least one carboxylic acid as the first solvent; c) at least one oxidizing agent; and d) at least one complexing agent selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids, An etching composition comprising: The at least one carboxylic acid is present in an amount of 85% to 99% by weight of the etching composition, The at least one carboxylic acid is selected from the group consisting of formic acid, acetic acid, trifluoroacetic acid, propionic acid, butyric acid, valeric acid, and caproic acid, The etching composition has an etching selectivity of Ta / Cu and / or TaN / Cu of 10 or more, Etching composition.

2. The hydrofluoric acid is present in an amount of 0.1% to 5% by weight of the etching composition, and the etching composition according to claim 1.

3. The at least one carboxylic acid is present in an amount of 85% to 98% by weight of the etching composition, and the etching composition according to claim 1.

4. The at least one oxidizing agent is nitric acid, KMnO ４ , H ２ O ２ , H ５ IO ５ , or NaClO ４ , The etching composition according to claim 1.

5. The at least one oxidizing agent is present in an amount of 0.01% to 0.5% by weight of the etching composition, and the etching composition according to claim 1.

6. The at least one complexing agent contains oxalic acid, citric acid, or 2-hydroxybenzoic acid, and the etching composition according to claim 1.

7. The at least one complexing agent is present in an amount of 0.1% to 10% by weight of the etching composition, and the etching composition according to claim 1.

8. The etching composition according to claim 1 further comprises at least one hexafluorosilicate compound.

9. The at least one hexafluorosilicate compound is H ２ SiF ６ , Na ２ SiF ６ , K ２ SiF ６ , or (NH ４ ) ２ SiF ６ The etching composition according to claim 8, comprising

10. The at least one hexafluorosilicate compound is present in an amount of 0.1% to 5% by weight of the etching composition, and the etching composition according to claim 8.

11. The etching composition according to claim 1 further comprises at least one sulfonic acid.

12. The at least one sulfonic acid contains p-toluenesulfonic acid, methanesulfonic acid, or dodecylbenzenesulfonic acid, and the etching composition according to claim 11.

13. The at least one sulfonic acid is present in an amount of 0.1% to 10% by weight of the etching composition, and the etching composition according to claim 11.

14. The etching composition according to claim 1, further comprising at least one second solvent selected from the group consisting of organic solvents and inorganic solvents.

15. The etching composition according to claim 14, wherein the at least one second solvent contains water.

16. The etching composition according to claim 15, wherein the water is present in an amount of 0.01% to 10% by weight of the etching composition.

17. The etching composition according to claim 14, wherein the at least one second solvent contains an organic solvent having a partition coefficient (logP) greater than 0.

18. The etching composition according to claim 17, wherein the organic solvent contains alcohol or ether.

19. The etching composition according to claim 17, wherein the organic solvent contains alcohol or alkylene glycol ether.

20. The etching composition according to claim 17, wherein the organic solvent contains benzyl alcohol, diethylene glycol butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl ether, tetraethylene glycol dimethyl ether, or dipropylene glycol dimethyl ether.

21. The etching composition according to claim 14, wherein the organic solvent is present in an amount of 0.1% to 10% by weight of the etching composition.

22. The etching composition according to claim 1, further comprising at least one surfactant.

23. The etching composition according to claim 22, wherein the at least one surfactant contains a nonionic surfactant.

24. The etching composition according to claim 22, wherein the at least one surfactant is present in an amount of 0.0001% to 1% by weight of the etching composition.

25. The etching composition according to claim 1, having a pH of 1 or less.

26. A method comprising contacting a semiconductor substrate containing Ta or TaN with the etching composition according to claim 1 to remove the Ta or TaN.

27. The method according to claim 26, further comprising rinsing the semiconductor substrate with a rinse solvent after contacting the semiconductor substrate containing Ta or TaN with the etching composition to remove the Ta or TaN.

28. The method according to claim 27, further comprising drying the semiconductor substrate after rinsing the semiconductor substrate with a rinse solvent.

29. The method according to claim 26, wherein Cu or a dielectric material on the semiconductor substrate is not substantially removed.

30. a) hydrofluoric acid; b) at least one carboxylic acid; and c) at least one complexing agent selected from the group consisting of polycarboxylic acids and hydroxycarboxylic acids, An etching composition comprising: wherein the at least one carboxylic acid is present in an amount of 85% to 99% by weight of the etching composition; the hydrofluoric acid is present in an amount of 0.1% to 5% by weight of the etching composition; the at least one complexing agent is present in an amount of 0.1% to 10% by weight of the etching composition; the etching composition further comprises at least one oxidizing agent in an amount of 0.01% to 0.5% by weight of the etching composition; the at least one carboxylic acid is selected from the group consisting of formic acid, acetic acid, trifluoroacetic acid, propionic acid, butyric acid, valeric acid, and caproic acid; the etching composition has a Ta / Cu and / or TaN / Cu etching selectivity of 10 or more. Etching composition.

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