CMP slurry composition for polishing copper barrier layers

Abstract

The present invention relates to a slurry composition for copper barrier layer polishing for chemical mechanical planarizing (CMP) of tantalum nitride or tantalum as an anti-diffusion film in the presence of an interconnect structure material in an integrated circuit device. The slurry composition according to the present invention contains abrasive particles, a heterocyclic compound, an organic acid, a surface protecting agent, a nitride, a pH adjuster, and a balance of deionized water, and exhibits the effect of providing an excellent slurry composition having a large polishing selectivity and few dishing and defect numbers.

Description

Technical Field

[0001] The present invention relates to a CMP slurry composition for polishing a copper barrier layer for chemical mechanical planarization (CMP) of tantalum nitride or tantalum as a diffusion prevention film in the presence of an interconnect structure material in an integrated circuit device. The CMP slurry composition according to the present invention is a useful composition containing abrasive particles, a heterocyclic compound, an organic acid, a surface protective agent, a nitride, a pH adjuster, and a balance of deionized water, and is excellent in the dispersibility and stability of the abrasive particles compared to the CMP slurry composition according to the prior art, has a large polishing selectivity ratio, and can provide an excellent CMP slurry composition with less dishing and fewer defects.

Background Art

[0002] In recent years, with the development of semiconductor manufacturing process technology, in the semiconductor industry, when forming integrated circuits, there has been an increasing dependence on copper electrical interconnects. These copper interconnects have a low electrical resistivity and excellent electromigration characteristics.

[0003] Copper has many advantages in terms of efficiency such as excellent electromigration characteristics and low electrical resistance, and has thus been widely used as a main electrical connection material for semiconductor integrated circuits such as highly miniaturized and highly integrated ULSIs.

[0004] However, since patterning by dry etching is difficult and there is a limit in that copper cannot be used in integrated circuits, in order to overcome this, a method of forming a copper interconnect by a CMP process using a dual damascene process has been proposed. Copper forms a porous oxide film layer composed of CuO, CuO2, Cu(OH)3, etc., which contain Cu+ or Cu2+ copper oxide ions during the CMP process.

[0005] However, copper is relatively weaker than other materials such as silicon-based tetraethoxysilane (TEOS) or tungsten, and is also more susceptible to corrosion electrochemically than tungsten. Therefore, while the polishing speed can be high, over-polishing, dishing, and erosion due to scratches can easily occur. In particular, components of the polishing slurry and foreign substances such as oxides generated during the polishing process can penetrate the copper oxide film layer through the pores of the porous film. Such phenomena can cause problems in subsequent processes such as photolithography. Especially in the case of high-level integrated circuits composed of 6 to 7 or more layers depending on the wiring design, considering that the performance of the circuit depends on the flatness of each layer, this can be a cause of fatal defects.

[0006] Since copper is highly reactive with many dielectric materials, such as silicon dioxide and low-K or doped versions of silicon dioxide, a diffusion barrier layer is necessary to prevent the diffusion of copper into the underlying dielectric material.

[0007] Typical barrier materials include tantalum, tantalum nitrides, tantalum-silicon nitrides, titanium, titanium nitrides, titanium-silicon nitrides, titanium-titanium nitrides, titanium-tungsten, tungsten, tungsten nitrides, and tungsten-silicon nitrides.

[0008] In response to the increasing demand for high-density integrated circuits, manufacturers are now assembling integrated circuits that contain multiple overlapping layers of metal interconnect structural materials. Planarizing each interconnect layer during device assembly improves packing density, process uniformity, and production quality, and most importantly, enables chip manufacturers to assemble multi-layer integrated circuits. Chip manufacturers rely on chemical-mechanical planarization (CMP) as a relatively efficient means of producing flat surfaces.

[0009] The CMP process is typically carried out in two stages. First, the polishing process uses a "first stage" slurry specifically designed to quickly remove copper.

[0010] After the initial removal of copper, the "second stage" slurry removes the barrier material. Typically, the second stage slurry requires excellent selectivity in removing the barrier material without adversely affecting the physical structure or electrical properties of the interconnecting material. Commercial second stage slurries typically have a basic or neutral pH, as alkaline polishing slurries have a much higher Ta / TaN removal rate than acidic slurries. Another factor highlighting the advantages of neutral or basic pH barrier metal polishing slurries concerns the need to preserve metal that overlaps the barrier metal during second-stage polishing. The metal removal rate must be very low to reduce dishing of the metal interconnecting material.

[0011] Therefore, in chemical mechanical polishing methods, such barrier slurry compositions require a high barrier removal rate, very low post-polishing topography, absence of corrosion defects, and very low scratching or corrosion. Depending on the type of abrasive, oxidizing agent, or additive selected, it is possible to effectively polish metal insulating films, diffusion walls, or metal layers at the desired polishing ratio while minimizing the range of variation in each of the variables important in semiconductor processes, such as imperfection, surface roughness, surface defects, erosion, and corrosion of the polished surface.

[0012] Experiments using conventional CMP slurry compositions revealed several problems: insufficient polishing of copper and tantalum, resulting in reduced CMP work volume; decreased equipment performance and reduced production yield due to copper corrosion; layer planarization; and dishing during polishing. Furthermore, in the process of polishing a copper film, it is necessary to achieve a low surface defect level along with an appropriate polishing speed. However, conventional CMP slurry compositions suffer from problems such as prolonged polishing time or the appearance of surface defects. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Korean Patent Application Publication No. 10-1465604 Specification [Patent Document 2] Korean Patent Application Publication No. 10-1548715 Specification [Patent Document 3] Korean Patent Application Publication No. 10-1698490 Specification [Patent Document 4] Korean Patent Application Publication No. 10-2021-0095548 Specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0014] The object of the present invention is to solve problems such as the amount of CMP work performed due to insufficient polishing of copper and tantalide in conventional CMP slurry compositions, the deterioration of equipment performance and the reduction in production yield due to corrosion of copper materials, the problem of layer flattening, and the dishing phenomenon that occurs during polishing.

[0015] Furthermore, an object of the present invention is to provide a CMP slurry composition for polishing copper barrier layers that has an appropriate polishing speed in the process of polishing copper films while significantly reducing dishing, corrosion, and the number of defects compared to existing slurries.

[0016] Furthermore, an object of the present invention is to provide a CMP slurry composition for polishing copper barrier layers that has a greater step removal rate for silicon oxide films and copper films than conventional slurries, addressing one of the problems in the copper CMP process mentioned above. [Means for solving the problem]

[0017] To achieve the above objectives, the present invention provides a CMP slurry composition for polishing copper barrier layers, comprising abrasive particles made of colloidal silica, a heterocyclic compound, an organic acid, a surface protective agent, a nitrogen oxide, a pH adjuster, and a residual amount of deionized water, characterized in that the polishing selectivity ratio and polishing rate for silicon oxide films, tantalum films, and copper films are adjusted by adjusting the content of the additives and solvent and adjusting the particle size of the colloidal silica.

[0018] In a preferred embodiment of the present invention, the colloidal silica is characterized by having a particle size of 75 nm to 95 nm.

[0019] In a preferred embodiment of the present invention, the heterocyclic compound is characterized by having two or more nitrogen atoms and being one or more selected from the group consisting of 1,2,4H-triazole, 5-methylbenzotriazole, tetrazole, imidazole, 1,2-dimethylimidazole, benzotriazole (BTA), 1H-benzotriazoleacetonitrile, and piperazine.

[0020] In a preferred embodiment of the present invention, the surface protective agent can be selected from nonionic types such as polyvinyl alcohol (PVA), ethylene glycol (EG), glycerin, polyethylene glycol (PEG), polypropylene glycol (PPG), or polyvinylpyrrolidone (PVP), and from anionic types such as ammonium dodecyl benzene sulfonate, ammonium polyoxyethylene alkyl sulfonate, or ammonium polyoxyethylene alkyl aryl sulfonate, and two or more of these can be used in mixture form. Most preferably, polyvinylpyrrolidone (PVP) as the nonionic type and ammonium dodecyl benzene sulfonate as the anionic type are used in mixture form.

[0021] In a preferred embodiment of the present invention, the organic acid may be any one selected from the group of carboxylic acids consisting of citric acid, glutaric acid, malic acid, maleic acid, oxalic acid, phthalic acid, succinic acid, tartaric acid, and acetic acid. Furthermore, it is characterized by being one or more amino acids selected from the group consisting of nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), methyl iminodiacetic acid (MIDA), hydroxyethyl iminodiacetic acid (HIDA), diethylenetriamine pentaacetic acid (DPTA), ethylenediamine tetraacetic acid (EDTA), N-hydroxyethyl ethylenediamine tetraacetic acid (HEDTA), methyl ethylenediamine tetraacetic acid (MEDTA), triethylenetetraamine hexaacetic acid (TTHA), and others.

[0022] In a preferred embodiment of the present invention, the antioxidant is characterized in that it is at least one selected from the group consisting of ascorbic acid, L(+)-ascorbic acid, isoascorbic acid, ascorbic acid derivatives, gallic acid, formamidinesulfinic acid, uric acid, tartaric acid, cysteine, and the like.

[0023] In a preferred embodiment of the present invention, in order to adjust the pH range to be basic, KOH, NH4OH, NaOH, TMAH, TBAH, KNO3, NH4NO3, HNO3, etc. can be used alone or in combination. Since the pH is closely related to the particle stability and polishing rate of the slurry, it must be precisely adjusted.

[0024] In a preferred embodiment of the present invention, the CMP slurry composition contains, based on the total weight of the composition, 13 wt% to 15 wt% of polishing particles composed of colloidal silica, polishing particles, heterocyclic compounds, organic acids, surface protectants, nitrides, pH adjusters, and the balance deionized water.

[0025] In a preferred embodiment of the present invention, the CMP slurry composition is characterized in that the pH is 9 to 12.

[0026] In a preferred embodiment of the present invention, the CMP slurry composition is characterized in that it simultaneously polishes a polished film formed of two or more selected from a silicon oxide film, a tantalum film, and a copper film.

[0027] In a preferred embodiment of the present invention, the polishing is characterized in that the polishing selectivity ratio of a tantalum nitride film (TaN), a silicon oxide film (Silicon oxide), and a copper film (Cu) is 1:1 to 4:0.5 to 1.

Advantages of the Invention

[0028] The CMP slurry composition for polishing copper barrier layers according to the present invention exhibits high efficiency in removing steps between the silicon oxide film and the copper film layer, thus improving productivity.

[0029] Furthermore, the CMP slurry composition for polishing copper barrier layers according to the present invention enables polishing while minimizing dishing, corrosion, and defects in the copper film layer, and allows for the efficient formation of copper wiring layers and other components of semiconductor device layers with excellent reliability and properties, thus significantly contributing to the acquisition of high-performance semiconductor devices. [Modes for carrying out the invention]

[0030] In general, the nomenclature used herein is well known and commonly used in the art. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by experts skilled in the art to which the invention pertains.

[0031] Throughout this specification, when a part is described as "containing" a component, this means, unless otherwise stated, that it may contain other components rather than excluding them.

[0032] Generally, in stage 1, after removing overburden copper, the polished wafer surface has uneven local and overall flatness due to differences in step height at various locations. Low-density pitchers tend to have high copper steps, while high-density pitchers tend to have low steps.

[0033] Due to the steps introduced after Stage 1, a Stage 2 CMP slurry with selective polishing for the removal rate of copper and oxides becomes essential.

[0034] In this invention, "selectivity ratio" means different removal rates for different substances under the same polishing conditions.

[0035] The barrier slurry preferably provides one or more of the following in the second step of the CMP process of a patterned wafer: a favorable removal rate for various types of films; a low level of wafer non-uniformity (WIW NU); low residue on the polished wafer after the CMP process; and a polishing selectivity ratio for various polished layers.

[0036] Specific featured distortion, which makes a product unsuitable for semiconductor manufacturing, is damage to copper vias or metal lines caused by chemical components interacting with them during the CMP process and resulting in additional corrosion. Therefore, it is crucial to use corrosion inhibitors in barrier CMP slurries to reduce additional corrosion of copper vias or trenches during the CMP process and to minimize defects.

[0037] The chemical reactions of the barrier CMP composition in the Stage 2 CMP process include oxidation reactions induced by an oxidizing agent used in the CMP slurry, such as H2O2. For example, metals such as copper, lines, vias, or trenches, and surfaces such as Ta are oxidized to their respective metal oxide films.

[0038] Typically, copper is oxidized to a mixture of cuprous or cupric oxide, and ta is oxidized to Ta2O5. Chelates, ligands, or other chemical additives that can chemically bind to copper and tantalum cations can be used in the barrier slurry to promote the dissolution of copper and tantalum oxides and improve the removal rate of copper, lines, vias, or trenches, and the barrier layer or barrier film.

[0039] Therefore, the present invention aims to provide a slurry composition for CMP that significantly reduces corrosion or defects occurring in the copper CMP process and enables faster polishing by increasing the polishing removal rate of silicon oxide film, copper film, and tantalum film compared to conventional slurries.

[0040] The copper barrier layer polishing slurry according to the present invention is composed of polishing particles made of colloidal silica, a heterocyclic compound, an organic acid, a surface protective agent, a nitrogen oxide, a pH adjuster, and the remainder being deionized water.

[0041] The colloidal silica refers to a colloidal solution in which nanoparticles of silica size do not settle and are stably dispersed in a solvent. The colloidal silica is preferably composed of particles with a size of 75 nm to 95 nm in order to appropriately maintain scratch resistance and removal rate, and is more preferably composed of particles with a size of 80 nm to 90 nm.

[0042] If the size of the colloidal silica particles is less than 75 nm, the removal rate from the film material decreases and the process time becomes longer. If the size of the colloidal silica particles exceeds 95 nm, it is undesirable because it is susceptible to scratching.

[0043] The colloidal silica is preferably present in an amount of 13% to 15% by weight relative to the total weight of the composition.

[0044] Using less than 13% by weight of colloidal silica results in insufficient solid content, leading to a reduced removal rate. Using more than 15% by weight of colloidal silica is undesirable because excessive content can cause aggregation.

[0045] In a CMP slurry composition according to one embodiment of the present invention, the heterocyclic compound is characterized by having two or more nitrogen atoms and being one or more selected from the group consisting of 1,2,4H-triazole, 5-methylbenzotriazole, tetrazole, imidazole, 1,2-dimethylimidazole, benzotriazole (BTA), 1H-benzotriazoleacetonitrile, or piperazine. The corrosion inhibitor may be present in an amount of 0.005% to 0.5% by weight in the slurry composition in terms of corrosion inhibition effect, polishing speed, and stability of the slurry composition.

[0046] If the amount of the corrosion inhibitor is less than 0.005% by weight, it becomes impossible to control the polishing of the copper film, which can lead to a dishing problem. On the other hand, if the amount of the corrosion inhibitor exceeds 0.5% by weight, the polishing rate of the copper film will be low, which can lead to a problem of residue remaining.

[0047] The polishing agent for tantalides that can be used in the CMP slurry of the present invention is a nitrogen compound used as a pH adjuster. Nitrogen compounds are substances used as etching solutions for tantalum and titanides, and are effective in removing tantalum during CMP polishing.

[0048] The nitrogenides used in this invention include potassium nitrate (KNO3), nitric acid (HNO3), ammonium nitrate (NH4NO3), iron nitrate (Fe(NO3)2), and copper nitrate (Cu(NO3)2), and can also be used in mixed compositions. Generally, titanium and tantalides are relatively stable substances that are easily etched with hydrofluoric acid and nitric acid mixtures and react slowly with basic substances and aqua regia. Generally, the amount of nitrogen used in the slurry is preferably in the range of about 0.05% to 10% by weight, and more preferably about 0.1% to 1% by weight.

[0049] The surface protective agents used in the present invention can be selected from nonionic types such as polyvinyl alcohol (PVA), ethylene glycol (EG), glycerin, polyethylene glycol (PEG), polypropylene glycol (PPG), or polyvinylpyrrolidone (PVP), and from anionic types such as ammonium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl sulfonate, or ammonium polyoxyethylene alkylaryl sulfonate, and two or more of these can be used in mixture form. Most preferably, polyvinylpyrrolidone (PVP) as the nonionic type and ammonium dodecylbenzenesulfonate as the anionic type are used in mixture form.

[0050] The nonionic protective agent adsorbs to the particle surface in the solution phase, and contains one or more functional groups that have affinity for the particles. It adsorbs strongly and persistently to the particle surface, thus increasing the particle size. Therefore, it also plays a role in appropriately improving the polishing rate against silicon oxide films. Furthermore, dispersion stability is maintained by steric repulsion. Consequently, if the content of the protective agent is less than 0.15% by weight of the total weight of the composition, the dispersion force is low and precipitation occurs quickly, resulting in precipitation during the transfer of the polishing solution and preventing uniform supply of the abrasive material. On the other hand, if the content of the dispersant exceeds 1.0% by weight of the total weight of the composition, a thick protective layer is formed around the abrasive particles, acting as a kind of cushion. This makes it difficult for the abrasive surface to contact the polishing surface, potentially lowering the polishing speed.

[0051] The surface protectant protects the wafer surface from residues of the polishing pad, metal residues, or organic residues during polishing, thereby reducing the number of defects on the wafer. In particular, when an anionic ammonium sulfonate derivative is mixed and used, it also plays a role in washing away various residues from the wafer surface, further improving the defect rate. Generally, the amount of surface protectant used in the slurry is preferably in the range of about 0.15% to 1.0% by weight, and most preferably in the range of about 0.3% to 0.8% by weight.

[0052] In the CMP slurry of the present invention, an organic acid is used to adjust the copper removal rate relative to the barrier metal removal rate.

[0053] Organic acids suppress the readsorption of copper oxide, which has been oxidized by chelation with copper oxide, onto the copper layer being polished, thereby increasing the polishing rate for copper and reducing surface defects. By selectively adding organic acids to the slurry according to the target metal component, the CMP planarization of dielectric / metal composite structures can be further improved.

[0054] This increases the erosion rate of the metallic phase, increases the polishing selectivity ratio of the metal to the removal of the dielectric phase, and makes the planarization process more efficient.

[0055] The organic acids that can be used in the present invention include carboxylic acid-based and amino acid-based acids. First, the carboxylic acid-based organic acid is characterized by being one or more selected from the group of carboxylic acids consisting of citric acid, glutaric acid, malic acid, maleic acid, oxalic acid, phthalic acid, succinic acid, tartaric acid, and acetic acid.

[0056] Secondly, the amino acid-based organic acid is characterized by being one or more selected from the group consisting of nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), methyl iminodiacetic acid (MIDA), hydroxyethyl iminodiacetic acid (HIDA), diethylenetriamine pentaacetic acid (DPTA), ethylenediamine tetraacetic acid (EDTA), N-hydroxyethyl ethylenediamine tetraacetic acid (HEDTA), methyl ethylenediamine tetraacetic acid (MEDTA), triethylene tetraamine hexaacetic acid (TTHA), and others.

[0057] The organic acid is added in an amount of 0.05% to 5% by weight based on the weight of the slurry composition. Preferably, the concentration is 0.1% to 3% by weight. Most preferably, the concentration is 0.1% to 1% by weight. If the amount is too small, the chelating agent will not exhibit the effect intended by the present invention, and if the amount is too large, the chelating agent will be consumed without any additional effect.

[0058] In a preferred embodiment of the present invention, the antioxidant is characterized by being one or more selected from the group consisting of ascorbic acid, L(+)-ascorbic acid, isoascorbic acid, ascorbic acid derivatives, gallic acid, formamidinesulfinic acid, uric acid, tartaric acid, cysteine, and the like. The antioxidant is added in an amount of 0.05% to 1% by weight based on the weight of the slurry composition. Preferably, the concentration is 0.1% to 0.5% by weight. Most preferably, the concentration is 0.2% to 0.3% by weight. If the amount is too small, the antioxidant effect on the metal will not be shown, and if the amount is too large, it will be consumed without any additional effect or will remain on the wafer surface, causing defects.

[0059] In one embodiment of the present invention, a CMP slurry composition with a pH of 9 to 12 is preferable in terms of composition stability. If the pH range is less than 9, the aggregation phenomenon and removal rate of colloidal silica particles become unstable, and if the pH range is greater than 12, the removal rate becomes unstable, which is undesirable.

[0060] To adjust the pH to the aforementioned range, basic substances such as KOH, NH4OH, NaOH, TMAH, TBAH, KNO3, and NH4NO3 can be used individually or in combination. Since the pH is closely related to the particle stability and polishing rate of the slurry composition, it must be precisely adjusted.

[0061] In a CMP slurry composition according to one embodiment of the present invention, the solvent is used to adjust the concentration of the composition and the rate of film removal. As the solvent, deionized water, water, etc., can be used, but it is preferable to use deionized water.

[0062] The film to be polished in the slurry composition may include a copper-containing film.

[0063] Furthermore, the slurry composition can be used to adjust the desired polishing rate for a copper-containing film and an oxide film used as a thin film or semiconductor insulating film that contains one of the following elements selected from the group consisting of titanium (Ti), tantalum (Ta), ruthenium (Ru), molybdenum (Mo), cobalt (Co), or gold (Au) used as a barrier film. As a result, the slurry composition can also exhibit an excellent polishing selectivity ratio between the film to be polished and other thin films.

[0064] The present invention will be described in more detail below through examples. However, it will be obvious to those ordinary in the art that these examples are merely illustrative and should not be construed as limiting the scope of the present invention. [Examples]

[0065] [Examples 1 to 7 and Comparative Examples 1 to 2] The copper barrier layer polishing slurry compositions of Examples 1 to 7 and Comparative Examples 1 to 2 were prepared using the content listed in Table 1 below.

[0066] Here, the colloidal silica content was set to 13% by weight in all cases, and the particle size of the colloidal silica used was 90 nm. KOH was used as the pH adjuster in all cases, and KNO3 was used as the nitrogen compound in all cases, with each at a concentration of 0.5% by weight. Ascorbic acid was used as the antioxidant at a concentration of 0.2% by weight.

[0067] [Table 1]

[0068] [Experimental Examples 1 to 7 and Comparative Experimental Examples 1 to 2] After measuring the removal rate and dishing for slurry compositions such as those in Examples 1 to 7 and Comparative Examples 1 and 2, the results were shown in Experimental Examples 1 to 7 and Comparative Experimental Example 1 and Comparative Experimental Example 2, and are listed in Table 2 below.

[0069] [Polishing Conditions] 1. Polishing Equipment: 12-inch (300 mm) CMP Equipment - AP-300 (CTS Corporation) 2. Polishing Pad: IC1010 (Dow Chemical Company) 3. Platen Speed: 103 rpm 4. Head Speed: 97 rpm 5. Flow Rate: 300 cc / min 6. Pressure: 2.2 psi

[0070] In the measurement of the polishing rate, when polishing using 12-inch (300 mm) CMP equipment, the polishing rates of Cu and Ta were calculated using a four-point probe (CMT-SR5000, AIT Co., Ltd).

[0071] For PTEOS, which is an oxide, the thickness change before and after CMP was measured using the Atlas equipment of Nanometrics, Inc., and the polishing rate was calculated.

[0072] The polishing selectivity was calculated based on the polishing rates of each film quality as follows. - Polishing selectivity of silicon oxide film with respect to tantalum nitride film (TaN) = Polishing rate of silicon oxide film / Polishing rate of tantalum nitride film (TaN) - Polishing selectivity of copper film (Cu) with respect to tantalum nitride film (TaN) = Polishing rate of copper film (Cu) / Polishing rate of tantalum nitride film (TaN)

[0073] In the measurement of dishing, the thickness of each film quality was measured and calculated as follows using a transmission electron microscope (JEM-2000, JEOL). - Cu dishing = (Cu edge thickness - Cu center thickness) - Ox dishing = (Ox edge thickness - Ox center thickness)

[0074] [Table 2]

[0075] The polishing rate, selectivity ratio, and dishing value for Experimental Examples 1 through 7 and Comparative Experimental Examples 1 and 2, as described in Table 2, are evaluated as follows.

[0076] Firstly, Experimental Examples 1 to 7, which use complexing agents, show a significant increase in the polishing rate of the copper film compared to the existing Comparative Examples 1 and 2.

[0077] Secondly, Experimental Examples 1 to 7, which use polyvinylpyrrolidone (PVP) as a surface protective agent, show a significant increase in the polishing rate of the silicon oxide film compared to the existing Comparative Examples 1 and 2.

[0078] Thirdly, in Experimental Examples 1 to 7, it can be seen that the polishing rate of the copper film increases as the content of the complexing agent iminodiacetic acid (IDA) increases, and the dishing of the copper film layer decreases as the content of the surface protective agent ammonium dodecylbenzenesulfonate (ADBS) increases.

[0079] For these reasons, Experimental Examples 1 through 7 showed superior selectivity compared to the existing comparative experimental examples 1 and 2.

[0080] In comparative experiment example 2, a lower content of the corrosion inhibitor benzotriazole (BTA) improves the polishing rate of the copper film layer, but it also leads to the problem of increased dishing.

[0081] [Examples 8 to 11 and Comparative Examples 3 to 5] Slurry compositions for polishing copper barrier layers were prepared using the content listed in Table 3 below for Examples 8 to 11 and Comparative Examples 3 to 5. Slurry compositions for polishing copper barrier layers were prepared using colloidal silica particle size and ADBS content as a surface protectant.

[0082] Here, the colloidal silica content was set to 15% by weight in all cases. BTA was used as the heterocyclic compound at 0.05% by weight, AA as the organic acid at 0.1% by weight, PVP as the surface protective agent at 0.2% by weight, KOH as the pH adjuster at 0.2% by weight, and KNO3 as the nitrogenized compound at 1.0% by weight.

[0083] [Table 3]

[0084] [Experimental Examples 8 to 11 and Comparative Experimental Examples 3 to 5] After measuring the polishing rate, selectivity ratio, and number of defects for slurry compositions such as Examples 8 to 11 and Comparative Examples 3 to 5, the results were shown in Experimental Examples 8 to 11 and Comparative Experimental Examples 3 to 5, and are presented in Table 4 below.

[0085] For measuring the number of defects, a 10 μm spot size light source equipped with the KLA-Tencor product name [AIT-XP+] was used.

[0086] [Table 4]

[0087] As shown in Table 4 above, while the polishing rate increases as the particle size increases, there is a problem in that the number of defects also increases. In comparative experiments 3 and 4 with particle sizes of 70 nm or less, the polishing rate of all two film materials decreases significantly, and the process time is delayed, resulting in productivity problems.

[0088] Furthermore, it was found that the number of defects decreased as the content of ammonium dodecylbenzenesulfonate (ADBS), a surface protective agent, increased.

[0089] [Examples 12 to 18 and Comparative Examples 6 to 7] The copper barrier layer polishing slurry compositions of Examples 12 to 18 and Comparative Examples 6 to 7 were prepared using the content listed in Table 5 below.

[0090] Here, the colloidal silica content was set to 15% by weight in all cases, and the particle size of the colloidal silica used was 90 nm. KOH was used as the pH adjuster in all cases, and KNO3 was used as the nitrogen compound in all cases, with each at a concentration of 0.5% by weight. Ascorbic acid was used as the antioxidant at a concentration of 0.2% by weight.

[0091] [Table 5]

[0092] [Experimental Examples 12 to 18 and Comparative Experimental Examples 6 to 7] After measuring the polishing rate, selectivity ratio, and dishing for slurry compositions such as Examples 12 to 18 and Comparative Examples 6 and 7, the results were shown in Table 6 below, and are presented in Experimental Examples 12 to 18 and Comparative Examples 6 and 7.

[0093] [Table 6]

[0094] The polishing rate, selectivity ratio, and dishing value for Experimental Examples 12 to 18 and Comparative Experimental Examples 6 and 7, as described in Table 6, were evaluated as follows.

[0095] Firstly, it can be seen that experimental examples 12 to 18, which use a complexing agent, show a significant increase in the polishing rate of the copper film compared to the existing comparative experimental examples 6 and 7.

[0096] Secondly, Experimental Examples 12 to 18, which use polyvinylpyrrolidone (PVP) as a surface protective agent, show a significant increase in the polishing rate of the silicon oxide film compared to the existing comparative experimental examples 6 and 7.

[0097] Thirdly, in Experimental Examples 12 to 18, it can be seen that the polishing rate of the copper film increases as the content of the complexing agent iminodiacetic acid (IDA) increases, and the dishing of the copper film layer decreases as the content of the surface protective agent ammonium dodecylbenzenesulfonate (ADBS) increases.

[0098] For these reasons, experimental examples 12 through 18 showed superior selectivity compared to the existing comparative experimental examples 6 and 7.

[0099] In comparative experiment example 7, because the content of the corrosion inhibitor benzotriazole (BTA) is low, the polishing rate of the copper film layer improves, but the problem of increased dishing arises.

[0100] [Examples 19 to 22 and Comparative Examples 8 to 10] The copper barrier layer polishing slurry compositions of Examples 19 to 22 and Comparative Examples 8 to 10 were prepared using the content listed in Table 7 below.

[0101] As shown in Table 7 below, slurry compositions for polishing copper barrier layers were prepared based on the particle size of the colloidal silica used and the content of ADBS, a surface protective agent.

[0102] Here, the colloidal silica content was set to 15% by weight in all cases, with BTA at 0.05% by weight as the heterocyclic compound, AA at 0.1% by weight as the organic acid, PVP at 0.2% by weight as the surface protective agent, KOH at 0.2% by weight as the pH adjuster, and KNO3 at 1.0% by weight as the nitrogenized product.

[0103] [Table 7]

[0104] [Experimental Examples 19 to 22 and Comparative Experimental Examples 8 to 10] After measuring the polishing rate and number of defects for slurry compositions such as Examples 19 to 22 and Comparative Examples 8 to 10, the results are shown in Table 8 below, labeled as Experimental Examples 19 to 22 and Comparative Experimental Examples 8 to 10.

[0105] For measuring the number of defects, a light source with a spot size of 10 μm, equipped with the product name [AIT-XP+] manufactured by KLA-Tencor, was used.

[0106] [Table 8]

[0107] The polishing rate, selectivity ratio, and number of defects for Experimental Examples 19 to 22 and Comparative Experimental Examples 8 to 10, as described in Table 8, are evaluated as follows.

[0108] In other words, as the particle size of colloidal silica increases, the polishing rate increases, but the number of defects also increases. In comparative experiments 8 and 9, where the particle size is 70 nm or less, the polishing rate of both film materials decreases significantly, and the process time is delayed, resulting in productivity problems.

[0109] Furthermore, it was found that the number of defects decreased as the content of ammonium dodecylbenzenesulfonate (ADBS), a surface protective agent, increased.

[0110] The results above showed the same trend for both 13% and 15% colloidal silica concentrations, ensuring reproducibility.

[0111] As described above, although the present invention has been explained in limited embodiments, it is not limited to the above embodiments, and a person with ordinary skill in the art to which the present invention belongs can make various modifications and variations from this description. For this reason, the scope of the present invention should not be limited to the embodiments described, but should be defined not only by the claims described later, but also by claims equivalent to those described therein.

Claims

1. A CMP slurry composition for polishing copper barrier layers, With respect to the total weight of the slurry composition, Abrasive particles 13% to 15% by weight; 0.005% to 0.5% by weight of heterocyclic compounds; Nitrogenated material 0.05% to 10% by weight; Organic acid 0.05% to 5% by weight; Surface protective agent 0.15% to 1% by weight; Antioxidant 0.05% to 1% by weight; pH adjusting agent for maintaining the pH of the slurry composition at 9 to 12; and Including the remaining deionized water, The abrasive particles include colloidal silica having a particle size of 75 nm to 95 nm. The heterocyclic compound comprises one or more selected from the group consisting of 1,2,4-H-triazole, 5-methylbenzotriazole, tetrazole, imidazole, 1,2-dimethylimidazole, benzotriazole (BTA), 1H-benzotriazoleacetonitrile, and piperazine. The aforementioned nitrogenated material includes one or more selected from the group consisting of potassium nitrate (KNO₃), nitric acid (HNO₃), ammonium nitrate (NH₄NO₃), iron nitrate (Fe(NO₃)₂), and copper nitrate (Cu(NO₃)₂). The aforementioned organic acid includes one or more selected from the group consisting of citric acid, glutaric acid, malic acid, maleic acid, oxalic acid, phthalic acid, succinic acid, tartaric acid, and acetic acid. The surface protective agent comprises one or more selected from the group consisting of polyvinyl alcohol (PVA), ethylene glycol (EG), glycerin, polyethylene glycol (PEG), polypropylene glycol (PPG), and polyvinylpyrrolidone (PVP). The aforementioned antioxidant comprises one or more selected from the group consisting of ascorbic acid, L(+)-ascorbic acid, isoascorbic acid, gallic acid, formamidinesulfinic acid, uric acid, and cysteine. The pH adjusting agent is a CMP slurry composition for polishing copper barrier layers, comprising one or more selected from the group consisting of KOH, NH₄OH, NaOH, TMAH, and TBAH.

2. The CMP slurry composition for polishing copper barrier layers according to claim 1, characterized in that the colloidal silica does not settle into nanoparticle size silica particles and is stably dispersed in the solvent.

3. The CMP slurry composition for polishing copper barrier layers according to claim 1, characterized in that the nitrogen is contained in an amount of 0.1% to 10% by weight relative to the total weight of the slurry composition.

4. The aforementioned organic acids are nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), methyliminodiacetic acid (MIDA), hydroxyethyliminodiacetic acid (HIDA), diethylenetriaminepentaacetic acid (DPTA), ethylenediaminetetraacetic acid (EDTA), and N-hydroxyethylethylenediaminetetraacetic acid (N-hydroxyethylethylenediaminetetraacetic acid). The CMP slurry composition for polishing copper barrier layers according to claim 1, further comprising one or more selected from the group consisting of tetraacetic acid (HEDTA), methylethylenediaminetetraacetic acid (MEDTA), and triethylenetetramine hexaacetic acid (TTHA).

5. The CMP slurry composition for polishing copper barrier layers according to claim 1, characterized in that the organic acid is contained in an amount of 0.1% to 3% by weight relative to the total weight of the slurry composition.

6. The CMP slurry composition for polishing copper barrier layers according to claim 1, characterized in that the surface protective agent further comprises one or more selected from the group consisting of ammonium dodecylbenzene sulfonate, ammonium polyoxyethylene alkyl sulfonate, and ammonium polyoxyethylene alkylaryl sulfonate.

7. The CMP slurry composition for polishing copper barrier layers according to claim 1, characterized in that the surface protective agent is contained in an amount of 0.3% to 0.8% by weight relative to the total weight of the slurry composition.

8. The CMP slurry composition for polishing copper barrier layers according to claim 1, characterized in that the antioxidant is contained in an amount of 0.1% to 0.5% by weight relative to the total weight of the slurry composition.

9. The CMP slurry composition for polishing copper barrier layers according to Claim 1, characterized in that the film to be polished includes a copper-containing film and an oxide film used as a thin film or semiconductor insulating film, which contains one selected from the group consisting of titanium (Ti), tantalum (Ta), ruthenium (Ru), molybdenum (Mo), cobalt (Co), and gold (Au) used as a barrier film.

10. The CMP slurry composition for polishing copper barrier layers according to claim 9, characterized in that the polishing selectivity ratio of the tantalum nitride film (TaN), silicon oxide film, and copper film (Cu) is 1:1 to 4:0.5 to 1.

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