Soluble metal oxide anionic CMP slurry

Abstract

A soluble metal oxide anionic CMP slurry. The present invention provides a chemical mechanical polishing solution for metal and metal nitride substrates, comprising: a solvent; at least one abrasive having a Mohs hardness of at least 8; and at least one soluble metal oxide anion, wherein the metal is selected from the group consisting of vanadium, niobium, tantalum, chromium, molybdenum and tungsten.

Description

Technical Field The present invention relates to the field of chemical mechanical polishing. Specifically, the present invention relates to a chemical mechanical polishing composition for metal polishing. Background Art

[0001] In the fabrication of integrated circuits and other electronic devices, multiple layers of conductive, semiconductive, and dielectric materials are deposited onto and removed from the surface of a semiconductor wafer. Many deposition techniques can be used to deposit thin layers of conductive, semiconductive, and dielectric materials. Deposition techniques common in modern wafer processing include physical vapor deposition (PVD) (also known as sputtering), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), and electroless plating, among others.

[0002] As the material layers are sequentially deposited and removed, the uppermost surface of the wafer becomes non-planar. Since subsequent semiconductor processing (e.g., metallization) requires the wafer to have a flat surface, planarization of the wafer is needed. Planarization can be used to remove undesired surface topography and surface defects, such as rough surfaces, agglomerated materials, lattice damage, scratches, and contaminated layers or materials. In advanced semiconductor applications, planarization is particularly critical in polishing metal layers adjacent to non-metal layers. Additionally, controlling metal dishing and dielectric erosion is becoming increasingly important.

[0003] Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique used to planarize or polish a workpiece, such as a semiconductor wafer. In conventional CMP, a wafer carrier or polishing head is mounted on a carrier assembly. The polishing head holds the wafer and positions it in contact with the polishing layer of a polishing pad, which is mounted on a table or platen within a CMP apparatus. The polishing slurry provides the correct balance of removal rate, selectivity, dishing, and erosion to meet the characteristics of modern semiconductors.

[0004] Metals and metal nitrides, such as cobalt, copper, molybdenum, tungsten, titanium nitride, and tantalum nitride are used in semiconductor manufacturing to form metal lines and contact vias for intermediate layers connecting metal lines in an integrated circuit. Most semiconductors use copper metal lines to connect semiconductor features, such as transistors. Titanium nitride and tantalum nitride can be used as barrier films to protect the dielectric from copper diffusion. In the formation of vias, vias are etched through an interlayer dielectric (ILD) to an interconnect or semiconductor substrate. Then a thin adhesion layer, such as titanium nitride or titanium, can be formed on the ILD and into the etched vias. Then a cobalt, molybdenum, or tungsten film is deposited blanketly on the adhesion layer and into the vias. Then the excess cobalt, molybdenum, or tungsten is removed by chemical mechanical polishing to form tungsten vias.

[0005] The chemical mechanical polishing composition used in through - hole polishing is an important variable that determines the success of the process. Depending on the choice of abrasive and other additives, the chemical mechanical polishing composition can be customized to provide effective polishing of the different layers present at the desired polishing rate while minimizing surface defects, flaws, corrosion, and erosion of the interlayer dielectric adjacent to the tungsten through - hole. In addition, the chemical mechanical polishing composition can be used to provide controlled polishing selectivity for other materials (such as silicon oxide, titanium, titanium nitride, silicon nitride, etc.) present at the surface of the substrate being polished.

[0006] Typically, tungsten polishing is accomplished using a chemical mechanical polishing composition that contains abrasive particles and chemical reagents. Conventional polishing compositions for tungsten polishing use fine particles of alumina (Al2O3) or silica (SiO2) as the abrasive along with Fenton catalysts or reagents. Fenton reagents typically operate at an acidic pH far below 3.5 in a harsh oxidation environment. However, in many cases, the resulting composition etches tungsten in a way that chemically etches tungsten from the surface rather than converting tungsten into a soft oxide film that is more easily removed from the surface by mechanical abrasion. Due to this enhanced chemical action, such compositions tend to cause recesses in the tungsten plugs. Recessed tungsten through - holes, where the surface of the tungsten in the through - hole is below the surface of the surrounding interlayer dielectric material, can cause electrical contact problems in other areas of the device. In addition, recesses at the center of the tungsten through - hole can lead to an increase in non - planarity of the devices on subsequent levels of the device. Etching tungsten from the center of the through - hole can also cause undesirable "perforation".

[0007] Nonetheless, there is a continuing need for new chemical mechanical polishing compositions for polishing and planarizing metals and metal nitrides on semiconductor wafers. Summary of the Invention

[0008] Aspects of the present invention provide a chemical mechanical polishing solution for metal and metal nitride substrates, comprising: a solvent; at least one abrasive having a Mohs hardness of at least 8; and at least one soluble metal oxide anion, wherein the metal is selected from vanadium, niobium, tantalum, chromium, molybdenum, and tungsten.

[0009] Another aspect of the present invention provides a chemical mechanical polishing solution for metal and metal nitride substrates, comprising: a solvent; functionalized carbon - based particles having oxygen - containing functional groups, the oxygen - containing functional groups reacting with a peroxy moiety to increase the oxygen - to - carbon atom ratio on the functionalized carbon - based particles, the functionalized carbon - based particles containing at least 10 weight percent of sp3 structures, wherein the functionalized carbon - based particles contain at least 0.01 atomic percent of oxygen and wherein the surface of the functionalized carbon - based particles has an oxygen - to - carbon atom ratio of at least 0.01; and at least one soluble metal oxide anion, wherein the metal is selected from vanadium, niobium, tantalum, chromium, molybdenum, and tungsten. Description of the Drawings Figure 1 The crystal structure of the functionalized carbon-based particles 2-1 measured by X-ray diffraction is provided. Figure 2 The Raman spectroscopic data of the functionalized carbon-based particles 2-1 are provided. Figure 3 The FTIR spectra of the surfaces of multiple functionalized carbon-based particles are provided. Detailed Description of the Invention

[0010] The polishing slurry of the present invention can be used for polishing and planarizing semiconductor substrates containing metals and metal nitrides. Specifically, the solution can be used for cobalt, copper, molybdenum, tungsten, titanium nitride, and tantalum nitride layers. The polishing formulation of the present invention provides effective removal rates for soft metals (such as cobalt, copper, and titanium), hard metals (such as molybdenum and tungsten), and metal nitrides (such as titanium nitride and tantalum nitride). In addition, it can provide effective selectivity with respect to dielectric layers (such as TEOS and silicon nitride layers).

[0011] The slurry functions through functionalized carbon-based particles having oxygen-containing functional groups. Advantageously, the oxygen-containing functional groups are COOH and its salts, COOOH and its salts, OH-, ketones, ethylene oxide, or a combination thereof. Most advantageously, the functional groups are COOH and its salts or COOOH and its salts. The functionalized carbon-based particles have oxygen-containing functional groups that react with a peroxide moiety to increase the oxygen on the carbon-based particles. For example, the COOH and its salt groups can react with the peroxide moiety to form the COOOH- group. Optionally, the carbon-based particles can also contain amine (NH2) groups, hydroxyl (OH) groups, sulfonate (SO3) groups, or hydrocarbon (C-H) groups.

[0012] The carbon-based particles contain sp3-containing structures for effective removal rates of metals and metal nitrides. Non-sp3 carbon structures (such as pure graphite, graphene, and amorphous carbon) do not provide effective removal rates of metals and metal nitrides. For example, the carbon particles contain at least 10 weight percent of sp3-containing structures. Advantageously, the carbon particles contain at least 30 weight percent of sp3-containing structures. Most advantageously, the carbon particles contain at least 50 or even 60 weight percent of sp3-containing structures. The functionalized carbon-based particles contain at least 0.01 atomic percent of oxygen. Advantageously, the functionalized carbon-based particles contain at least 0.02 atomic percent of oxygen. Most advantageously, the functionalized carbon-based particles contain at least 0.025 atomic percent of oxygen. In addition, the surface of the carbon-based particles has an oxygen-to-carbon atom ratio of at least 0.01. Most advantageously, the surface of the carbon-based particles has an oxygen-to-carbon atom ratio of at least 0.02. The oxygen associated with the carbon-based particles increases the removal rate of the metal and metal nitride substrates. When sp3-containing carbon particles are not used, similar oxygenated compounds (such as peracetic acid) in the solution do not provide an improvement in the removal rate. These polishing slurries can offer the advantage of operating without a Fenton catalyst or reagent. Thus, for some formulations, it is advantageous to operate via an iron-free formulation. These formulations can operate at higher pH levels where there is less hydrogen peroxide, which can result in a lower static etch rate.

[0013] Optionally, the polishing slurry contains a Fenton catalyst or reagent. Examples of Fenton catalysts or reagents include at least one transition metal catalyst selected from the group consisting of metal salts of Ag, Co, Cr, Cu, Fe, Mo, Mn, Nb, Ni, Os, Pd, Ru, Sn, Ti, and V and mixtures thereof. Most advantageously, the Fenton reagent is iron and examples of suitable iron-based catalysts include iron(III) sulfate, iron(III) nitrate, iron(III) chloride, iron(III) oxalate, potassium tris(oxalato)ferrate(III), ammonium hexacyanoferrate(III), potassium hexacyanoferrate(III), iron(III) citrate, ammonium iron(III) citrate. The typical amount of the Fenton reagent is from 1 to 5000 ppm and advantageously from 5 to 1000 ppm. When using a Fenton reagent, it is advantageous to use a stabilizer for the hydroxyl radical. Examples of stabilizers include the following: citric acid, lactic acid, malic acid, maleic acid, malonic acid, oxalic acid, tartaric acid, phytic acid, gluconic acid. Most advantageously, the stabilizer is malonic acid. The typical amount of the stabilizer is from 0.001 to 1 wt.%. Advantageously, the stabilizer is in an amount of from 0.005 to 0.5 wt.%. For the purposes of this patent application, unless otherwise specified, all concentrations are expressed as weight percentages.

[0014] The carbon-based particles can have a cubic phase or an sp3 core and a non-cubic carbon outer surface. The cubic-phase carbon core provides hard particles that contribute to the polishing removal rate. Additionally, the non-cubic carbon outer surface can reduce scratches that may originate from within the diamond. For example, the surface of the carbon-based particles can include graphene, graphite, amorphous carbon, or a mixture thereof.

[0015] The carbon-based hybrid particles typically have an average diameter of 0.2 to 200 nm. Advantageously, the carbon-based hybrid particles have an average diameter of 0.5 to 100 nm. Most advantageously, the carbon-based hybrid particles have an average diameter of 0.1 to 50 nm. Different from conventional colloidal silica particles, the carbon-based hybrid particles can be effective when the average diameter measured by scanning electron microscopy is 1 to 10 nm or even 0.5 to 5 nm. Additionally, the carbon-based hybrid particles are effective at a concentration of 1 ppm to 10 wt%. Advantageously, the carbon-based hybrid particles are present in an amount of 1 ppm to 500 ppm. Most advantageously, the carbon-based hybrid particles are present in an amount of 2 ppm to 200 ppm.

[0016] The functionalized carbon-based abrasives act through peroxide moieties. These peroxide moieties can be inorganic or organic per-compounds. For the purposes of this application, a peroxide moiety is a compound containing one or more peroxide groups (-O-O-). As examples of compounds containing one or more peroxide groups, although not limited thereto, hydrogen peroxide and its adducts, such as urea hydrogen peroxide, percarbonates, benzyl peroxide, peracetic acid, di-tert-butyl peroxide, monopersulfate (SO5 2- )-based compounds, disulfate (S2O8 2- )-based compounds, sodium peroxide, performic acid, propanperoxoic acid; substituted or unsubstituted butanperoxoic acid; hydroperoxy-acetaldehyde and mixtures thereof. Most advantageously, the oxidizing agent is hydrogen peroxide. For hydrogen peroxide, the end user can typically add hydrogen peroxide at the point of use by mixing hydrogen peroxide into the storage tank before use.

[0017] Optionally, the slurry contains an inhibitor for metals or metal nitrides. The inhibitor is particularly important when polishing cobalt, copper, molybdenum, and tungsten. Examples of cobalt inhibitors include heterocyclic nitrogen compounds selected from the group consisting of benzotriazole, adenine, 1,2,4-triazole, imidazole, polyimidazole, and mixtures thereof. Examples of copper inhibitors include azole inhibitors, where the azole inhibitors are selected from the group consisting of benzotriazole, mercaptobenzotriazole, tolyltriazole, imidazole, and combinations thereof. Examples of molybdenum inhibitors include amino acids, nitrogen-containing heterocyclic compounds such as pyridine, pyrazine, piperidine, pyridazine, pyrimidine, benzotriazole, benzothiazole, triazole, indole, or zwitterionic surfactants. The inhibitor is typically present in an amount of 0.005 to 2 wt.%. Most advantageously, the inhibitor is typically present in an amount of 0.01 to 1 wt.%.

[0018] When polishing tungsten, cationic inhibitors are optimal for controlling static etching. Typical inhibitors include amines such as primary amines, secondary amines, tertiary amines, and quaternary amines. Examples of these amines include amino acids such as arginine, histidine, proline, lysine, glycine, tryptophan, alanine, and cysteine. Advantageously, the tungsten inhibitor is a cationic nitrogen-containing polymer or copolymer containing primary amines, secondary amines, tertiary amines, and quaternary amines, cationic polyvinyl alcohol, cationic cellulose, and combinations thereof. Examples of cationic nitrogen-containing polymers or copolymers include polyallylamine, poly(4-aminostyrene) polyvinylimine, poly(N-methylvinylamine), chitosan, poly(vinyl-1-methylpyridinium) halide, polylysine, poly(vinylimidazolium), poly(methacryloyloxyethyltrimethylammonium) halide, poly(methacryloyloxyethyl-trimethylammonium) halide, poly(diallyldimethylammonium) halide, and polyquaternary ammonium compounds. The nitrogen-containing polymer inhibitor typically is present in an amount of 0.0001 to 1 wt.%. Most advantageously, the nitrogen-containing polymer inhibitor typically is present in an amount of 0.001 to 0.5 wt.%.

[0019] In addition to the carbon-based hybrid particles, the polishing compositions described herein can contain a second abrasive. The abrasive typically is a metal oxide abrasive, which preferably is selected from the group consisting of silica, alumina, titanium dioxide, zirconia, germanium dioxide, cerium dioxide, and mixtures thereof. Advantageously, the second abrasive is silica. The addition of a mixture of silica abrasive, Fenton catalyst or reagent in combination with a corrosion inhibitor can further increase the metal removal rate. The silica can be fumed silica or colloidal silica. When silica is added, typically it has a concentration of 0.01 wt% to 5 wt%. Most advantageously, the silica has a concentration of 0.1 to 2 wt.%. The typical average diameter of the silica is 10 to 200 nm and for colloidal silica is 20 to 100 nm. Alternatively, the carbon-based hybrid particles can be added in an amount of 1 to 1000 ppm to further increase the metal removal rate of slurries containing Fenton reagents. Most advantageously, these particles are added in an amount of 1 to 100 ppm.

[0020] For solutions without Fenton's reagent, as measured under the conditions of 1 wt% hydrogen peroxide of Example 17, the solution typically contains less than 0.01 μM of hydroxyl radicals. Advantageously, when measured under the conditions of 1 wt% hydrogen peroxide of the examples, the solution without Fenton's reagent contains less than 0.005 μM of hydroxyl radicals. Most advantageously, when measured under the conditions of 1 wt% hydrogen peroxide of the examples, the test does not detect the presence of hydroxyl radicals. Similarly, as measured under the conditions of 1 wt% hydrogen peroxide of Example 17, for solutions containing molybdic acid, they typically contain less than 0.1 μM of hydroxyl radicals. Advantageously, the solution containing molybdic acid advantageously contains less than 0.05 μM of hydroxyl radicals. When the solution contains ions of Fenton's catalyst, when measured under the conditions of 1 wt% hydrogen peroxide of Example 17, it contains at least 0.5 μM of hydroxyl radicals. Advantageously, when measured under the conditions of 1 wt% hydrogen peroxide of Example 17, the solution containing Fenton's reagent contains at least 1 μM of hydroxyl radicals.

[0021] Optionally, the slurry comprises at least one soluble metal oxide anion, wherein the metal is selected from vanadium, niobium, tantalum, chromium, molybdenum, and tungsten. The metal oxide anion is soluble in the solvent of the CMP slurry, such as an aqueous solvent. Advantageously, the metal oxide anion is soluble in deionized water. Examples of suitable metal oxide anions include molybdic acid, silicomolybdic acid, and phosphomolybdic acid. Most advantageously, the metal oxide anion is molybdic acid. The structure of these metal oxide anions is advantageously [M x O y -n . Where x and y are 1 or greater than 1 and n is at least 1. The metal oxide anion typically exists in an amount of 100 ppm to 1 wt%. In addition to the carbon-based hybrid particles, these formulations will function with any particles having a hardness of at least 8. For example, alumina, diamond, silicon carbide, and boron nitride particles will function. Most advantageously, the slurry uses carbon-based hybrid particles. Typically, these slurries contain 50 ppm to 1000 ppm of abrasive particles having a hardness of at least 8. A hardness of at least 8 is important for providing mechanical wear to tungsten metal, which also has a similar Mohs hardness.

[0022] ​One potential drawback of functional carbon-based particles is that they are unstable in acidic solutions with a pH of about 4 or lower. Additionally, functional carbon-based particles are only stable at a pH of 4 to 4.5 in the presence of molybdic acid. It has been found that oligomers or polymers having at least 50 mol% of R1-C(O)-N[-R2,-R3] units, where R1, R2, -R3 are selected from at least one of H, saturated or unsaturated aromatic or aliphatic groups, aryl, cycloaliphatic hydrocarbons, or mixtures thereof, can stabilize carbon-based hybrid particles. In particular, these oligomers or polymers stabilize carbon-based particles at all acidic pH levels. Additionally, these oligomers or polymers can stabilize carbon-based particles at all acidic pH levels in the presence of molybdic acid. In addition to stabilizing carbon-based hybrid particles, these oligomers or polymers coordinate with tungsten and provide effective inhibition of static etching of tungsten when coupled with cationic species. Specific examples of oligomers or polymers for stabilizing slurries are as follows: salicylhydroxamic acid, poly(N-isopropylacrylamide), polyacrylamide, poly(2-ethyl-2-oxazoline), polyvinylpyrrolidone. Alternatively, these polymers can be copolymers or block copolymers. Examples of suitable copolymers are as follows: polyquaternium-16 and polyquaternium-44 compounds, poly(acrylamide-co-diallyldimethylammonium chloride), poly(acrylamide-co-acrylic acid), where the R1-C(O)-N[-R2,-R3] units are greater than 50 mol%. Advantageously, these represent polymers having a number average molecular weight of 200 to 2,000,000. Most advantageously, these represent polymers having a number average molecular weight of 500 to 1,000,000. Typically, the oligomers or polymers are present in an amount of 1 ppm to 10,000 ppm. Advantageously, the oligomers or polymers are present in an amount of 10 ppm to 1,000 ppm.

[0023] The polishing slurry functions in a solvent, such as an aqueous or organic solvent or a mixture of aqueous and organic solvents. Typically, the solvent is an aqueous solvent. Advantageously, the aqueous solvent is deionized water. The polishing solution advantageously contains a balance of deionized water. However, for some applications, it is advantageous to include up to 10 wt.% of an alcohol solvent in the formulation. Additionally, the solvent optionally includes a polar protic solvent or a combination of polar protic solvents, such as methanol and ethanol (in any desired ratio), such as 100%, 90%:10%, 80%:20%, 70%:30%, and 60%:40%.

[0024] Optionally, the slurry contains a metal chelating agent / complexing agent, which can prevent the unwanted redeposition of insoluble metal oxide substances or accelerate metal removal, wherein the complexing agent is selected from the group consisting of citric acid, lactic acid, malic acid, maleic acid, malonic acid, oxalic acid, tartaric acid, phytic acid, gluconic acid, L-aspartic acid, nitrilotriacetic acid, nitrilotri(methylphosphonic acid), ethylenediamine-N,N'-disuccinic acid trisodium salt, and ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid.

[0025] The polishing composition may also optionally contain a buffering agent, such as various organic and inorganic bases or their salts having a pKa in the pH range of greater than 1 to 6. The polishing composition may further optionally contain an antifoaming agent, such as nonionic surfactants, including esters, ethylene oxide, alcohols, ethoxylates, silicon compounds, fluorine compounds, ethers, glycosides, and their derivatives, etc. The antifoaming agent may also be an amphoteric surfactant. The polishing composition may optionally contain a biocide, such as Kordex TM MLX (9.5%-9.9% methyl-4-isothiazolin-3-one, 89.1%-89.5% water, and 1.0% related reaction product) or Kathan containing the active ingredients 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one TM ICP III, each manufactured by the Dow Chemical Company (Kathan and Kordex are trademarks of the Dow Chemical Company).

[0026] Preferably, the slurry polishes the semiconductor substrate by applying the slurry to the semiconductor substrate with a downward force of 27.6 kPa or less applied to a polishing pad. The downward force represents the force exerted by the polishing pad on the semiconductor substrate. The polishing pad may have a circular shape, a strip shape, or a mesh configuration. Such a low downward force is particularly useful for planarizing the semiconductor substrate to remove the barrier material from the semiconductor substrate. Most preferably, the polishing is performed at a downward force of less than or equal to 13.8 kPa.

[0027] Examples

[0028] Example 1

[0029] Polishing Conditions: UMT Tribolab polishing machine, 9-inch (22.9 cm) diameter IC1010 concentric circular groove polyurethane polishing pad, manufactured by DuPont, slurry flow rate: 40 ml / min, 3 psi (20.7 kPa), 211 rpm platen speed, 207 rpm carrier speed, 2.6×2.6 cm square tungsten blanket wafer, using a 4.25-inch diameter Saesol AK-45 diamond dresser (170 μm diamond, with 315 μm pitch). Table 1 Note: Particle 2-1 has an average particle size of 125 μm. Table 1-1

[0030] Examples of pure graphite and amorphous C nanoparticles did not provide a significant tungsten polishing removal rate. Hybrid cubic carbon nanoparticles with an oxygenated surface (O / C ratio > 0.06 / XPS) increased the tungsten removal rate.

[0031] Figure 1 XRD peaks of the hybrid particles of Particle 2-1 measured under the following conditions are provided: Instrument: Panalytical Empyrean powder diffractometer Mode: Reflection Radiation: Optics: BBHD with 1 / 8° divergence slit, 20 mm mask Detector: Pixcel 1D line detector, with 1 / 8° slit, PHD 35 / 75, 0.04° Soller slit, 3.347° measurement window, Ni filter Sample Preparation: Transfer the powder to a low-back round stainless steel deep well holder and immediately place it in the instrument for measurement. Quantitative phase ID is performed by measuring a corundum standard (external K-factor). Scan Time: 2 hours Scan Start, Stop and Step: 10°, 90°, 0.1° Data Analysis: Rietveld refinement is performed in Panalytical HighScore Plus 4.5 using the corundum standard as the intensity reference. The crystallite size of the cubic carbon phase is determined using line profile analysis with silicon powder as the line broadening standard.

[0032] Figure 1 The data indicate that the particles include cubic, tetragonal, and graphite phases.

[0033] Figure 2 The Raman measurements were taken under the following conditions: A Horiba LabRam HR Raman microscope, using 785 nm excitation. A 10x objective (Olympus NA 0.4) was used in the measurements. The Duoscan rasterization option available in the instrument was used to sample each spectrum over a 50×50 μm area. The spectra reported here are the result of averaging the responses from at least 3 separate areas. The power was kept very low (around 200 - 400 mW) to avoid altering the sample during the measurement. Model: LabRam HR Raman microscope Spot size: 50×50 μm Excitation wavelength: 785 nm Power: around 300 mW Integration time: 20 sec

[0034] Reference Figure 2 , the Raman peak at 1313 cm-1 is consistent with cubic phase carbon. Additionally, the Raman peak at 1598 cm-1 is consistent with the graphite peak.

[0035] Figure 3 The data were measured using a diamond ATR-IR (DATR) with an integrated diamond crystal FTIR accessory, which is part of a Thermo iS-50 FTIR spectrometer. The spectra were scaled to absolute intensity to provide the ability to compare responses at least on a semi-quantitative basis. These FTIR spectra indicate that the surface of the hybrid carbon particles is functionalized with -COOH. Additionally, the polishing data in Table 1-1 indicate that the functionalized carbon particles with cubic cores provide the highest tungsten polishing rate.

[0036] Example 2

[0037] A series of wafers were compared using 2.6 cm × 2.6 cm square molybdenum wafers and the polishing conditions of Example 1. Table 2 below provides the formulations at acidic and alkaline pH levels. Table 2

[0038] Table 2.1 below provides the molybdenum removal rates of the polishing slurries in Table 2. Table 2.1

[0039] Tables 2 and 2.1 combined indicate that the C particles 2-1 of the hybrid structure with a particle concentration less than one-tenth are superior to silica, cerium dioxide, alumina, and silicon carbide abrasive particles at acidic pH levels. At alkaline pH levels, the Mo RR is generally lower, but the C particles 2-1 of the hybrid structure still exhibit much better polishing efficiency than alumina and silicon carbide abrasive particles.

[0040] Example 3

[0041] A series of wafers were compared using 2.6 cm × 2.6 cm square molybdenum and TEOS wafers and the polishing conditions of Example 1. Table 3 below provides the formulations at multiple abrasive concentrations, hydrogen peroxide concentrations, and acidic pH levels. Table 3

[0042] Table 3.1 below provides the molybdenum and TEOS removal rates of the polishing slurries in Table 3 along with the coefficient of friction. Table 3.1 CoF = coefficient of friction; RR = removal rate; TEOS = oxidation product of tetraethyl orthosilicate

[0043] Compared with titanium dioxide and zirconia, the C particles 2-1 of the hybrid structure exhibit much higher molybdenum removal rates while maintaining lower TEOS removal rates. Thus, the slurry provides increased and improved Mo / TEOS removal selectivity. In addition, despite the higher molybdenum removal rate, the hybrid particles 2-1 of the hybrid structure also show a lower coefficient of friction. Compared with the silica particle formulation using iron-containing Fenton reagent chemicals, the molybdenum removal rate achieved with the hybrid particles 2-1 of the hybrid structure is higher in the pH range of 2.5 to 4.5 and under the abrasive wt% effect without using Fenton chemicals.

[0044] Example 4

[0045] A series of wafers were compared using 2.6 cm × 2.6 cm square molybdenum wafers and the polishing conditions of Example 1. Table 4 below provides various hybrid particle formulations at an acidic 2.5 pH level. Table 4

[0046] Table 4.1 below provides the molybdenum removal rate of the polishing slurries in Table 4 along with the coefficient of friction. Table 4.1 CoF = coefficient of friction; RR = removal rate

[0047] Among the types of hybrid carbon nanoparticles, slurries with a cubic structure (111) percentage in the range of 63 to 99 according to XRD provided a significant enhancement in the molybdenum removal rate. Examples 16 and 18 provided excellent removal rates and low coefficient of friction values.

[0048] Example 5

[0049] A series of wafers were compared using 2.6 cm × 2.6 cm square cobalt and TEOS (silica) wafers and the polishing conditions of Example 1. Table 5 below provides the formulations at 2.75. Table 5 Note: Particle 2-2 has an average diameter of 50 nm. Table 5-1 RR = removal rate; TEOS = oxidation product of tetraethyl orthosilicate

[0050] Table 5-1 shows that a polishing solution containing peracetic acid does not increase the tungsten removal rate. However, hybrid carbon particles containing a COOH functional group provided a significant increase in the tungsten removal rate. Since the peracetic acid in the solution includes a peroxy moiety, this indicates that the COOH functional group must be attached to the hybrid carbon particles and activated by hydrogen peroxide for effective tungsten removal.

[0051] Example 6

[0052] In this example, 100 ppm of hybrid C particles 2.2 were mixed with increasing amounts of hydrogen peroxide. Table 6 below provides the hydrogen peroxide concentration and the resulting O / C atomic ratio, as measured by EDS (energy dispersive x-ray spectroscopy) from scanning transmission electron microscopy (STEM). Table 6 sample O / C atomic ratio <![CDATA[0.1 wt% H2O2]]> 0.006±0.002 <![CDATA[0.25 wt% H2O2]]> 0.009±0.003 <![CDATA[0.5 wt% H2O2]]> 0.010±0.006 <![CDATA[1 wt% H2O2]]> 0.015±0.011 <![CDATA[2 wt% H2O2]]> 0.053±0.037

[0053] These data show that the oxygen concentration on the surface of the hybrid C particles increases with the concentration of hydrogen peroxide.

[0054] Example 7

[0055] A series of wafers were compared using 2.6 cm × 2.6 cm square copper and tantalum nitride wafers and the polishing conditions of Example 1. Table 7 below provides the formulations at pH 6.8 and 2.5. Table 7

[0056] Table 7.1 below provides the copper and tantalum nitride removal rates of the polishing slurries of Table 7. Table 7.1 * Commercial slurry R is a bulk copper slurry; RR = removal rate

[0057] Compared with commercial R, the examples show that using the carbon particle 2-1 abrasive with a hybrid structure having an appropriate BTA level achieved comparable or higher copper removal rates and much higher TaN removal rates.

[0058] Example 8

[0059] Using 200 mm wafers, a Mirra polishing tool from Applied Materials was used at a platen speed of 93 rpm; a carrier speed of 87 rpm; a slurry flow rate of 125 ml / min, and a downforce of 3 psi (20.7 kPa). A series of wafers were compared using an IK4250EH polishing pad. Table 8 below provides the formulations with and without molybdic acid, iron nitrate, or colloidal silica at a pH of 2.5. Table 8

[0060] Table 8.1 below provides the tungsten, TEOS, silicon nitride, titanium nitride, and titanium removal rates of the polishing slurries of Table 8. Table 8.1 RR = removal rate; TEOS = oxidation product of tetraethyl orthosilicate

[0061] Combining Tables 8 and 8.1 shows that the hybrid carbon particles act in a cumulative manner with iron nitrate and colloidal silica to increase the removal rate. In addition, molybdic acid acts with the hybrid particles to further increase the removal rates of tungsten, titanium nitride, and titanium. Molybdic acid has little effect on the silicon nitride and TEOS removal rates.

[0062] Example 9

[0063] A series of wafers were compared using 2.6 cm × 2.6 cm square cobalt and TEOS (silica) wafers and the polishing conditions of Example 1. Table 9 below provides the formulations at 2.5 and 8. Table 9

[0064] Table 9.1 below provides the cobalt and TEOS removal rates of the polishing slurries of Table 9. Table 9.1 RR = Removal rate; TEOS = Oxidation product of tetraethyl orthosilicate

[0065] These tables show that the functionalized carbon-based particles provide a substantial increase in the cobalt removal rate, with no significant effect on the TEOS removal rate.

[0066] Example 10

[0067] Polishing conditions: AMAT Reflexion polisher, 30-inch (76.2 cm) diameter IKONIC TM 4121H concentric circular groove polyurethane polishing pad, manufactured by DuPont, slurry flow rate: 250 ml / min, 1 psi (6.9 kPa), 115 rpm platen speed, 125 rpm carrier speed, 12-inch tungsten and TEOS blanket wafer, using a 4.25-inch diameter Kinik I-PDA 33A-3 disk. Table 10 below provides 3 different formulations with and without a dispersant. Measurement: SP2, defects > 0.08 μm. Table 10 Note: Particles 2 - 3 have an average diameter of 5 nm. Note: Luviquat FC370 is a polymeric quaternary ammonium salt formed from methyl vinylimidazolium chloride and vinylpyrrolidone (3:7 molar ratio). Table 10.1 RR = Removal rate; TEOS = Oxidation product of tetraethyl orthosilicate

[0068] These data show that the polymeric dispersant reduces chatter marks defects of the contaminating carbon particles.

[0069] Example 11

[0070] A series of wafers were compared using 2.6 cm × 2.6 cm square W, Mo, and TEOS (silica) wafers and the polishing conditions of Example 1. Table 11 below provides the formulations at 2.5. Table 11 Table 11.1 Table 11.2 RR = Removal rate; TEOS = Oxidation product of tetraethyl orthosilicate

[0071] These data combined indicate that the combination of molybdic acid and silica abrasive particles does not increase the tungsten removal rate. However, the combination of molybdic acid and comminuted carbon particles is effective in increasing the removal rate.

[0072] Example 12

[0073] A series of 2.6 cm x 2.6 cm square W, Mo, and TEOS (silica) wafers were compared using the polishing conditions of Example 1. Table 12 below provides the formulations at pH 2.5. Table 12 Table 12.1 RR = removal rate; TEOS = oxidation product of tetraethyl orthosilicate

[0074] These data indicate that molybdic acid, tungstic acid, and vanadate all increase the tungsten and molybdenum removal rates of both comminuted carbon particles and SiC particles.

[0075] Example 13

[0076] A series of 2.6 cm x 2.6 cm square W, Mo, and TEOS (silica) wafers were compared using the polishing conditions of Example 1. Table 13 below provides the formulations at pH 2.5. Table 13 Table 13.1 RR = removal rate; TEOS = oxidation product of tetraethyl orthosilicate

[0077] These data indicate that molybdic acid and its derivatives all increase the tungsten removal rate without increasing the TEOS removal rate.

[0078] Example 14

[0079] This example provides an example of a dispersant for comminuted carbon particles using nitric acid as a titrant at pH 3. Table 14 Note: Luviquat FC370 is a polymeric quaternary ammonium salt formed from methylvinylimidazolium chloride and vinylpyrrolidone (3:7 molar ratio). Table 14.1 Note: Normalization is compared with the reference slurry AC, and the LUMiSizer is a dispersion analyzer from LUM GmbH for measuring sedimentation, flotation or consolidation and calculating the velocity distribution in a centrifugal field.

[0080] These data indicate that polymer dispersants containing a -C(=O)-NH- moiety can reduce the particle sedimentation rate.

[0081] Example 15

[0082] Table 15 below provides formulations in weight percentages for particle stability using a nitric acid titrant with 0.01 wt% carbon particle abrasive 2-2 of a hybrid structure containing 0.3 wt% molybdic acid. Table 15-A Table 15-B Table 15-1 slurry 3 hours 1 day 1 week 1 month AF settled AG settled AH settled 51 stable 52 stable AI settled 53 stable 54 stable 55 stable 56 stable 57 stable 58 stable AJ settled AK settled

[0083] These data indicate that polymer dispersants containing a -C(=O)-NH- moiety can reduce the particle sedimentation rate.

[0084] Example 16

[0085] Table 16 below provides formulations using a nitric acid titrant at pH 3 with 0.01 wt% carbon particle abrasive 2-2 of a hybrid structure and 0.3 wt% molybdic acid (except for AL) for static etch control.

[0086] Experimentally, a series of 2.6 cm × 2.6 cm square tungsten wafers were immersed in the slurry at 55 °C for 3 minutes. The static etch rate was calculated by (wafer thickness after etching - wafer thickness before etching) / 3. Table 16 Note: PAS-5 is a diallylamine hydrochloride acrylamide copolymer from Nitto Boseki Co., Ltd. Table 16.1

[0087] These data indicate that in the presence of molybdic acid, anionic and nonionic polymers do not act as corrosion inhibitors for controlling the static etch rate of tungsten. However, cationic nitrogen-containing polymers can reduce the static etch rate of tungsten to a low level. Specifically, these polymers can achieve a reduction in the static etch rate of greater than fifty percent.

[0088] Example 17

[0089] All samples contained 1 μM terephthalic acid and the samples were immediately injected into ultra-high performance liquid chromatography after mixing with the specified amount of hydrogen peroxide. The expected final product hydroxyterephthalic acid (“HPA”) was used to reflect the amount of hydroxyl formation. HPA was determined (effluent peaks were measured at an initial interval of 5.1 minutes and a subsequent interval of 4.5 minutes). These peaks were then quantified by extracting ion chromatograms with mass spectrometry.

[0090] The reaction of hydroxyl with HPA is as follows: Table 17

[0091] Samples containing Fenton's reagent promoted the formation of hydroxyl radicals. Different from the examples containing Fenton's reagent, the functionalized carbon-based particles without Fenton's reagent did not promote the formation of hydroxyl radicals. Specifically, the presence of hydroxyl radicals was not detected in the samples without Fenton's reagent. Similarly, the samples containing molybdic acid did not promote the significant formation of hydroxyl radicals.

Claims

1. A chemical mechanical polishing solution for metal and metal nitride substrates, comprising: A solvent; At least one abrasive having a Mohs hardness of at least 8; and At least one soluble metal oxide anion, wherein the metal is selected from vanadium, niobium, tantalum, chromium, molybdenum, and tungsten.

2. The polishing solution according to claim 1, wherein, The at least one abrasive is selected from alumina, boron nitride, silicon carbide, diamond, and mixtures thereof.

3. The polishing solution according to claim 1, wherein, The soluble metal oxide anion is selected from the group consisting of molybdic acid, silicomolybdic acid, and phosphomolybdic acid.

4. A chemical mechanical polishing solution for metal and metal nitride substrates, comprising: A solvent; Functionalized carbon-based particles having oxygen-containing functional groups, the oxygen-containing functional groups reacting with a peroxy moiety to increase the oxygen-to-carbon atom ratio on the functionalized carbon-based particles, the functionalized carbon-based particles containing at least 10 weight percent of sp3 structures, wherein the functionalized carbon-based particles contain at least 0.01 atomic percent of oxygen and wherein the surface of the functionalized carbon-based particles has an oxygen-to-carbon atom ratio of at least 0.01; and At least one soluble metal oxide anion, wherein the metal is selected from vanadium, niobium, tantalum, chromium, molybdenum, and tungsten.

5. The polishing solution according to claim 4, wherein, The oxygen-containing functional groups are COOH and its salts, COOOH and its salts, OH-, ketone, ethylene oxide, or a combination thereof.

6. The polishing solution according to claim 1, wherein, The metal and metal nitride are selected from the group consisting of cobalt, copper, molybdenum, tungsten, titanium nitride, and tantalum nitride.

7. The polishing solution according to claim 1, wherein, The oxidizing agent is hydrogen peroxide and contains less than 0.1 μM of hydroxyl groups.

8. The polishing solution according to claim 1, wherein, The polishing solution is iron-free.

9. The polishing solution according to claim 1, wherein, The soluble metal oxide anion is molybdic acid.

10. The polishing solution according to claim 1, wherein, The functionalized carbon-based particles contain at least 30 weight percent of sp3 structures.

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