Functionalized carbon particle tungsten CMP slurry

Abstract

To provide a functionalized carbon particle CMP slurry dispersion.SOLUTION: The present invention provides a chemical mechanical polishing liquid for tungsten-containing substrates. The polishing liquid contains a water-based solvent and functionalized carbon particles with oxygen-containing functional groups. The functionalized carbon particles have oxygen-containing functional groups that react with the peroxide portion to increase the oxygen-to-carbon atom ratio on the functionalized carbon particles. The functionalized carbon particles contain at least 10 wt% of sp3-containing structures, the functionalized carbon particles contain at least 0.01 atomic % of oxygen, and the surface of the functionalized carbon particles has an atomic oxygen to carbon ratio of at least 0.01. In addition, the polishing liquid contains 1 ppm to 1000 ppm of nitrogen-containing cationic polymer to reduce the static etching rate of the tungsten-containing substrate by the polishing liquid.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to the field of chemical mechanical polishing. In particular, the present invention relates to a chemical mechanical polishing composition for metal polishing.

Background Art

[0002] In the manufacture of integrated circuits and other electronic devices, multiple layers of conductive, semiconductive, and dielectric materials are deposited on and removed from the surface of a semiconductor wafer. Thin layers of conductive, semiconductive, and dielectric materials can be deposited using a number of deposition techniques. Common deposition techniques in current wafer processing include, in particular, physical vapor deposition (PVD), also known as sputtering, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), and electrochemical plating.

[0003] As layers of material are successively deposited and removed, the top surface of the wafer becomes non-flat. Since subsequent semiconductor processing (e.g., metallization) requires the wafer to have a flat surface, it is necessary to planarize the wafer. Planarization is useful for removing undesirable surface topography and surface defects such as rough surfaces, agglomerated materials, damage to the crystal lattice, scratches, and contaminated layers or materials. Planarization is particularly important when polishing metal layers adjacent to non-metal layers in advanced semiconductor applications. Furthermore, control of metal dishing and dielectric erosion is becoming increasingly important.

[0004] Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique used to planarize or polish workpieces such as semiconductor wafers. In conventional CMP, a wafer carrier, or polishing head, is attached to a carrier assembly. The polishing head holds the wafer and positions the wafer in contact with the polishing layer of a polishing pad attached to a table or platen within a CMP apparatus. The polishing slurry provides the correct balance of removal rate, selectivity, dishing, and erosion in order to connect the features of modern semiconductors.

[0005] Metals and metal nitrides such as cobalt, copper, molybdenum, tungsten, titanium nitride and tantalum nitride are used in semiconductor manufacturing for the formation of metal lines within integrated circuits and contact vias that connect between layers of the metal lines. Most semiconductors use copper metal lines to connect semiconductor devices such as transistors. Titanium nitride and tantalum nitride can function as barrier films to protect dielectrics from copper diffusion. In the formation of via holes, they are etched through an interlayer dielectric (ILD) to an interconnect line or semiconductor substrate. Next, a thin adhesion layer of, for example, titanium nitride or titanium can be formed over the ILD and within the etched via hole. Then, a cobalt, molybdenum or tungsten film is blanket deposited over the adhesion layer and within the via. Excess cobalt, molybdenum or tungsten is then removed by chemical mechanical polishing to form a tungsten via.

[0006] The chemical mechanical polishing composition used for via polishing is an important variable in determining the success of the process. Depending on the selection of the abrasive and other additives, the chemical mechanical polishing composition can be adjusted to provide effective polishing of the various layers present at a desired polishing rate while minimizing surface defects, defects, corrosion, and erosion of the interlayer dielectric adjacent to the tungsten via. Further, the chemical mechanical polishing composition may be used to provide controlled polishing selectivity with respect to other materials present on the surface of the substrate being polished, such as silicon oxide, titanium, titanium nitride, silicon nitride, and the like.

[0007] Typically, tungsten polishing is achieved using a chemical mechanical polishing composition that includes polishing particles and a chemical reagent. Conventional polishing compositions for tungsten polishing use alumina (Al2O3) or silica (SiO2) fine particles as the polishing material with a Fenton's catalyst or reagent. The Fenton's reagent operates in a harsh oxidation environment at an acidic pH much lower than 3.5. However, in many cases, the resulting composition etches tungsten by chemically etching tungsten from the surface instead of converting tungsten on the surface to 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 tungsten plugs. A concave tungsten via where the surface of the tungsten within the via is below the surface of the surrounding interlayer dielectric material can cause problems with electrical contact to other areas of the device. Further, a recess in the center of the tungsten via can lead to an increase in device non-planarity at subsequent levels of the device. Etching of tungsten from the center of the via can also cause undesirable "keyholing".

[0008] Nevertheless, there remains a need for new chemical mechanical polishing compositions for polishing and planarizing semiconductor wafers for metals and metal nitrides. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0009] One aspect of the present invention is a chemical mechanical polishing liquid for a tungsten-containing substrate, comprising: an aqueous solvent; functionalized carbon-based particles having an oxygen-containing functional group, wherein the functionalized carbon-based particles react with a peroxy moiety to increase the oxygen-to-carbon atom ratio on the functionalized carbon-based particles, the functionalized carbon-based particles contain at least 10 wt% of an SP3-containing structure, the functionalized carbon-based particles contain at least 0.01% oxygen, and the surface of the functionalized carbon-based particles has an atomic oxygen-to-carbon ratio of at least 0.01%; and a nitrogen-containing cationic polymer from 1 ppm to 1000 ppm to reduce the static etching rate of the tungsten-containing substrate by the polishing liquid, the chemical mechanical polishing liquid is provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0011] The polishing slurry of the present invention is useful for polishing and planarizing metal and metal nitride-containing semiconductor substrates. In particular, this solution is useful 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. Furthermore, it can provide effective selectivity for dielectric layers such as TEOS and silicon nitride layers.

[0012] The slurry acts with 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, oxiranes or combinations thereof. Most advantageously, the functional groups are COOH and its salts or COOOH and its salts. The functionalized carbon-based particles having oxygen-containing functional groups react with the peroxy moiety to increase the oxygen on the carbon-based particles. For example, the COOH group and its base can react with the peroxy moiety to form COOOH- groups. Optionally, the carbon-based particles may also contain amine (NH2) groups, hydroxyl (OH) groups, sulfonate (SO3) groups or hydrocarbon (C-H) groups.

[0013] The carbon-based particles contain an sp3-containing structure for the effective removal rate of metals and metal nitrides. Non-sp3 carbon structures such as pure graphite, graphene and amorphous carbon do not provide an effective removal rate of metals and metal nitrides. For example, the carbon particles contain at least 10 wt% of an sp3-containing structure. Advantageously, the carbon particles contain at least 30 wt% of an sp3-containing structure. Most advantageously, the carbon particles contain at least 50 or even 60 wt% of an sp3-containing structure. The functionalized carbon-based particles contain at least 0.01 atomic% of oxygen. Advantageously, the functionalized carbon-based particles contain at least 0.02 atomic% of oxygen. Most advantageously, the functionalized carbon-based particles contain at least 0.025 atomic% of oxygen. Also, the surface of the carbon-based particles has an atomic ratio of oxygen to carbon of at least 0.01. Most advantageously, the surface of the carbon-based particles has an atomic ratio of oxygen to carbon of at least 0.02. The oxygen associated with the carbon-based particles increases the removal rate of the metal and metal nitride substrates. Similar oxygen compounds in solutions such as peracetic acid do not improve the removal rate when sp3-containing carbon particles are not used. These polishing slurries can offer the advantage of operating without a Fenton's catalyst or reagent. Thus, in some formulations, it is advantageous to operate with an iron-free formulation. These formulations can operate at a higher pH level with less hydrogen peroxide, which can result in a lower static etching rate.

[0014] Optionally, the polishing slurry may contain a Fenton's catalyst or reagent. Examples of Fenton's 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 preferably, the Fenton's reagent is iron, and examples of suitable iron-based catalysts include iron(III) sulfate, iron(III) nitrate, iron(III) chloride, iron(III) oxalate, potassium iron(III) oxalatoferrate, ammonium hexacyanoferrate(III), potassium hexacyanoferrate(III), iron(III) citrate, and ammonium iron(III) citrate. The typical amount of the Fenton's reagent is 1 to 5000 ppm, preferably 5 to 1000 ppm. When using a Fenton's reagent, it is advantageous to use a stabilizer for hydroxyl free radicals. Examples of stabilizers include: citric acid, lactic acid, malic acid, maleic acid, malonic acid, oxalic acid, tartaric acid, phytic acid, gluconic acid. Most preferably, the stabilizer is malonic acid. The typical amount of the stabilizer is from 0.001 to 1 wt%, preferably 0.005 to 0.5 wt%. For the purposes of this patent application, unless otherwise specified, all concentrations are expressed in wt%.

[0015] 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. Furthermore, 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 mixtures thereof.

[0016] 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. Unlike conventional colloidal silica particles, carbon-based hybrid particles can be effective even when the average diameter measured by a scanning electron microscope is 1 to 10 nm, and even more so 0.5 to 5 nm. Also, 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.

[0017] The functionalized carbon-based abrasive acts with peroxide moieties. These peroxide moieties can be inorganic or organic compound units. For the purposes of this application, a peroxide moiety is a compound containing one or more peroxide groups (-O-O-). Examples of compounds containing one or more peroxide groups include, but are not limited to, hydrogen peroxide and its adducts, such as hydrogen peroxide, percarbonate, benzoyl peroxide, peracetic acid, di-t-butyl peroxide, monopersulfate (SO52-) - based compounds, disulfate (S2O82-) - based compounds, sodium peroxide, peroxoformic acid, propanperoxoic acid, substituted or unsubstituted butanperoxoic acid, hydroperoxy - acetaldehyde, and mixtures thereof. Most advantageously, the oxidizing agent is hydrogen peroxide. When using hydrogen peroxide, the end user can usually add hydrogen peroxide at the time of use by mixing it into the storage tank before use.

[0018] Optionally, the slurry contains an inhibitor for the metal or metal nitride. 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 selected from the group consisting of benzotriazole, mercaptobenzotriazole, tritriazole, imidazole and combinations thereof. Examples of molybdenum inhibitors include nitrogen-containing heterocyclic compounds such as amino acids, 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% by weight. Most preferably, the inhibitor is typically present in an amount of 0.01 to 1% by weight.

[0019] When polishing tungsten, cation inhibitors work best to control static etching. Typical inhibitors include amines such as primary, secondary, tertiary, 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, secondary, tertiary, and quaternary amines, cationic polyvinyl alcohol, cationic cellulose, and combinations thereof. Examples of cationic nitrogen-containing polymers or copolymers include polyallylamine, poly(4-aminostyrene) polyethyleneimine, poly(N-methylvinylamine), chitosan, poly(vinyl-1-methylpyridinium) halide, polylysine, poly(vinylimidazolium), poly(methacryloyloxyethyltrimethylammonium) halide, poly(methacryloyloxyethyl-trimethylammonium) halide, poly(diallyldimethylammonium) halide, and polyquaternium compounds. The nitrogen-containing polymer inhibitor is typically present in an amount of 0.0001 to 1% by weight. Most advantageously, the nitrogen-containing polymer inhibitor is typically present in an amount of 0.001 to 0.5% by weight.

[0020] In addition to the carbon-based hybrid particles, the polishing composition described herein may contain a second abrasive. The abrasive is typically preferably a metal oxide abrasive selected from the group consisting of silica, alumina, titania, zirconia, germanium, ceria, and mixtures thereof. Advantageously, the secondary abrasive is silica. Adding a mixture of a silica abrasive, a Fenton's 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 adding silica, it typically 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 silica is 10 to 200 nm and 20 to 100 nm for colloidal silica. Alternatively, adding the carbon-based hybrid particles in an amount of 1 to 1000 ppm can further increase the metal removal rate of the Fenton's reagent-containing slurry. Most advantageously, these particles are added in an amount of 1 to 100 ppm.

[0021] In the case of a Fenton-free solution, the solution typically contains less than 0.01 μM of hydroxyl radicals as measured under the 1 wt% hydrogen peroxide conditions of Example 17. Advantageously, the Fenton-free solution contains less than 0.005 μM of hydroxyl radicals when measured under the 1 wt% hydrogen peroxide conditions of the examples. Most advantageously, the test does not detect the presence of hydroxyl radicals when measured under the 1 wt% hydrogen peroxide conditions of the examples. Similarly, for solutions containing molybdic acid, when measured under the 1 wt% hydrogen peroxide conditions of Example 17, they typically contain less than 0.1 μM of hydroxyl radicals. Advantageously, the molybdic acid-containing solution preferably contains less than 0.05 μM of hydroxyl radicals. When the solution contains Fenton catalyst-containing ions, the solution contains at least 0. When measured under the 1 wt% hydrogen peroxide conditions of Example 17, 5 μM of hydroxyl radicals. Advantageously, the Fenton-containing solution contains at least 1 μM of hydroxyl radicals when measured under the 1 wt% hydrogen peroxide conditions of Example 17.

[0022] Optionally, the slurry contains at least one soluble metal oxide anion, and 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 [MxOy]-n, where x and y are 1 or greater than 1, and n is at least 1. The metal oxide anion is typically present in an amount of 100 ppm to 1 wt%. In addition to the carbon-based hybrid particles, these formulations act with any particles having a hardness of at least 8. For example, alumina, diamond, silicon carbide, and boron nitride particles act. Most advantageously, the slurry uses carbon-based hybrid particles. Typically, these slurries contain 50 ppm to 1000 ppm of polishing particles having a hardness of at least 8. A hardness of at least 8 is important to provide mechanical wear against tungsten metal, which also has a similar Mohs hardness.

[0023] One potential drawback of functional carbon-based particles is that they are not stable in acidic solutions having a pH of about 4 or less. Further, the functional carbon-based particles are stable only at a pH of 4 to 4.5 in the presence of molybdic acid. It has been discovered 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 the carbon-based hybrid particles. In particular, these oligomers or polymers stabilize the carbon-based particles at all acidic pH levels. Further, these oligomers or polymers can stabilize the carbon-based particles in the presence of molybdic acid at all acidic pH levels. In addition to stabilizing the carbon-based hybrid particles, these oligomers or polymers coordinate with tungsten and, when bound to cationic species, effectively suppress the static etching of tungsten. 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) (wherein 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.

[0024] The polishing slurry functions in a solvent such as an aqueous or organic solvent or a mixture of an aqueous solvent and an organic solvent. Typically, the solvent is an aqueous solvent. Advantageously, the aqueous solvent is deionized water. The polishing liquid advantageously contains the balance of deionized water. However, in some applications, it is advantageous to include up to 10 wt% of an alcohol solvent in the formulation. Further, the solvent may optionally contain 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%.

[0025] Optionally, the slurry may contain a metal chelating agent / complexing agent that can prevent the undesirable redeposition of insoluble metal oxide species or promote metal removal, and 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), trisodium ethylenediamine-N,N'-disuccinate, and ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid.

[0026] The polishing composition can also optionally contain buffering agents such as various organic bases and inorganic bases having a pKa in the pH range of 1 to greater than 6, or salts thereof. The polishing composition can optionally further contain an antifoaming agent, for example, a nonionic surfactant including esters, ethylene oxide, alcohols, ethoxylates, silicon compounds, fluorine compounds, ethers, glycosides, and derivatives thereof. The antifoaming agent may be an amphoteric surfactant. The polishing composition can optionally contain a biocide, for example, Kordex™ MLX (9.5 - 9.9% methyl-4-isothiazolin-3-one, 89.1 - 89.5% water, and 1.0% related reaction product) or Kathan™ ICP III containing the active ingredients of 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, respectively, manufactured by The Dow Chemical Company (Kathan and Kordex are trademarks of The Dow Chemical Company).

[0027] The slurry preferably polishes the semiconductor substrate by applying a downward force of 27.6 kPa or less to the polishing pad and applying it to the semiconductor substrate. The downward force represents the force of the polishing pad on the semiconductor substrate. The polishing pad can have a circular, belt shape, or web configuration. This 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 with a downward force of 13.8 kPa or less.

Examples

[0028] Example 1 Polishing conditions: UMT Tribolab polisher, 9-inch (22.9 cm) made by DuPont, a polyurethane polishing pad with concentric circular grooves of diameter IC1010, slurry flow rate: 40 ml / min, 3 psi (20.7 kPa), a platen speed of 211 rpm, a carrier speed of 207 rpm, a 2.6×2.6 cm square tungsten blanket wafer with a Saesol AK-45 diamond conditioner of diameter 4.25 inches (diamond of 170 μm with a spacing of 315 μm).

[0029]

Table 1

[0030]

Table 2

[0031] Examples of pure graphite and amorphous C nanoparticles did not provide a significant tungsten polishing removal rate. Hybrid cubic carbon nanoparticles with an oxygen-containing surface (O / C ratio > 0.06 per XPS) increased the tungsten removal rate.

[0032] Figure 1 shows the XRD peaks of the hybrid particles of particle 2-1 measured under the following conditions: Instrument: PANalytical Empyrean powder diffractometer Mode: Reflection Radiation: CuK-alpha 1.54 Å Optics: 1 / 8° divergence slit, BBHD with a 20 mm mask Detector: Pixcel 1D line detector, with 1 / 8° slit, PHD 35 / 75, with 0.04° solar slit, with a 3.347° measurement window, Ni filter Sample preparation: The powder was transferred to a low-back round stainless steel deep well holder and immediately placed into the instrument for measurement. Quantitative phase ID was performed by measuring a corundum standard (external K factor). Scan time: 2 hours Scan start, stop, step size: 10°, 90°, 0.1° Rietveld refinement of the data analysis was performed in Panalytical HighScore Plus 4.5 using a corundum standard as the intensity standard. The crystallite size of the cubic carbon phase was determined using line profile analysis with silicon powder as the line broadening standard.

[0033] The data in Figure 1 show that the particles contain the cubic phase, tetragonal phase, and graphite phase.

[0034] The Raman measurements in Figure 2 were taken using the following conditions: Horiba LabRam HR Raman microscope using 785 nm excitation. A 10x objective lens (Olympus NA 0.4) was used for the measurement. Each spectrum was sampled over a 50×50 μm area using the Duoscan raster option available on this instrument. The spectra reported here are the result of averaging the responses from at least three separate areas. The output was kept very low (about 200 - 400 mW) to avoid sample changes during the measurement. Model: LabRam HR Raman microscope Spot size: 50x50μm Excitation wavelength: 785 nm Power: about 300 mW Integration time: 20 seconds

[0035] Referring to Figure 2, the Raman peak at 1313 cm-1 corresponded to the cubic phase carbon. Also, the Raman peak at 1598 cm-1 corresponded to the graphite peak.

[0036] The data in Figure 3 were measured using a Diamond ATR-IR (DATR) equipped 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 semi-quantitatively. These FTIR spectra indicate that the surface of the hybrid carbon particles was functionalized with both -COOH. Furthermore, the polishing data in Table 1-1 show that the functionalized carbon particles with cubic cores provided the highest tungsten polishing rate.

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

[0038] [Table 3]

[0039] Table 2.1 below shows the molybdenum removal rate of the polishing slurries in Table 2.

[0040] [Table 4]

[0041] Combining Tables 2 and 2.1 shows that hybrid structure C particles 2-1 with a particle concentration of less than 1 / 10 were superior to silica, ceria, alumina, and silicon carbide polishing particles at acidic pH levels. At alkaline pH levels, the Mo RR was generally low, but hybrid structure C particles 2-1 still showed much better polishing efficiency than alumina and silicon carbide polishing particles.

[0042] Example 3 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 formulations at multiple abrasive concentrations, hydrogen peroxide concentrations, and acidic pH levels.

[0043]

Table 5

[0044] Table 3.1 below shows the molybdenum and TEOS removal rates along with the coefficient of friction of the polishing slurries in Table 3.

[0045]

Table 6

[0046] Compared to titania and zirconia, the hybrid structure C particles 2-1 showed a much higher molybdenum removal rate while maintaining a lower TEOS removal rate. Thus, the slurry results in an improvement in Mo / TEOS removal selectivity. Further, despite the higher molybdenum removal rate, the hybrid structure hybrid particles 2-1 also showed a lower coefficient of friction. The molybdenum removal rate achieved using the hybrid structure hybrid particles 2-1 was higher in the pH range 2.5 - 4.5 and the polishing weight % effect without using Fenton chemistry compared to a silica particle formulation using iron-containing Fenton reagent chemistry.

[0047] Example 4 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 multiple hybrid particle formulations at an acidic 2.5 pH level.

[0048]

Table 7

[0049] Table 4.1 below shows the molybdenum removal rate along with the coefficient of friction of the polishing slurries in Table 4.

[0050]

Table 8

[0051] Among the types of hybrid carbon nanoparticles, the slurry having a percentage (111) of cubic crystal structure from XRD in the range of 63 - 99 brought about a significant improvement in the molybdenum removal rate. Examples 16 and 18 provided excellent removal rates with low friction coefficient values.

[0052] Example 5 A series of wafers were compared using 2.6 cm × 2.6 cm square cobalt and TEOS (silicon dioxide) wafers and the polishing conditions of Example 1. Table 5 below provides a formulation of 2.75.

[0053]

Table 9

[0054]

Table 10

[0055] Table 5 - 1 shows that the peracetic acid - containing polishing liquid does not increase the tungsten removal rate. However, the hybrid carbon particles containing COOH functional groups bring about a significant increase in the tungsten removal rate. Since peracetic acid in the solution contains a peroxide moiety, this indicates that the COOH functional groups must be bonded to the hybrid carbon particles and activated by hydrogen peroxide for effective tungsten removal.

Chemical formula

[0056] Example 6 In this example, 2.2 hybrid C particles at 100 ppm were mixed with incrementally increasing amounts of hydrogen peroxide. Table 6 below shows the hydrogen peroxide concentration measured by EDS (energy-dispersive X-ray spectroscopy) from a scanning transmission electron microscope (STEM) and the resulting O / C atomic ratio.

[0057]

Table 11

[0058] These data indicate that the oxygen concentration on the surface of the hybrid C particles increases with the concentration of hydrogen peroxide.

[0059] Example 7 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 formulations at pH 6.8 and 2.5.

[0060]

Table 12

[0061] Table 7.1 below shows the removal rates of copper and tantalum nitride for the polishing slurries in Table 7.

[0062]

Table 13

[0063] Compared with commercially available R, the example showed that equivalent or better copper removal rates and much higher TaN removal rates were achieved when using a hybrid-structured carbon particle 2-1 polishing agent with an appropriate BTA level.

[0064] Example 8 93 rpm platen speed; 87 rpm carrier speed; a series of wafers were compared using 200 mm wafers with an Applied Materials Mirra polishing tool having a slurry flow of 125 ml / min at a downforce of 3 psi (20.7 kPa) using an IK4250EH polishing pad. Table 8 below provides formulations at pH 2.5 with or without molybdic acid, iron nitrate or colloidal silica.

[0065]

Table 14

[0066] Table 8.1 below shows the tungsten, TEOS, silicon nitride, titanium nitride and titanium removal rates of the polishing slurries in Table 8.

[0067]

Table 15

[0068] Combining Tables 8 and 8.1 shows that the hybrid carbon particles act cumulatively with ferric nitrate and colloidal silica to increase the removal rate. Further, molybdic acid acts with the hybrid particles to further increase the removal rates of tungsten, titanium nitride and titanium. Molybdic acid had little effect on the removal rates of silicon nitride and TEOS.

[0069] Example 9 A series of wafers were compared using 2.6 cm × 2.6 cm square cobalt and TEOS (silicon dioxide) wafers and the polishing conditions of Example 1. Table 9 below provides formulations at 2.5 and 8.

[0070]

Table 16

[0071] The following Table 9.1 shows the cobalt and TEOS removal rates of the polishing slurry in Table 9.

[0072]

Table 17

[0073] The table demonstrates that the functionalized carbon-based particles result in a significant increase in the cobalt removal rate without significantly affecting the TEOS removal rate.

[0074] Example 10 Polishing conditions: AMAT Reflexion polisher, 30-inch (76.2 cm) diameter IKONIC™ 4121H concentric grooved polyurethane polishing pad made by DuPont, slurry flow rate: 250 ml / min, 1 psi (6.9 kPa), platen speed of 115 rpm, carrier speed of 125 rpm, 12-inch tungsten and TEOS blanket wafer with a 4.25-inch diameter Kinik I-PDA 33A-3 disk. The following Table 10 provides three different formulations with and without a dispersant. Measurement: SP2, defect > 0.08 um.

[0075]

Table 18

[0076]

Table 19

[0077] These data indicate that the polymer dispersant reduces the chatter mark defects of the hybrid carbon particles.

[0078] Example 11 A series of wafers were compared using 2.6 cm × 2.6 cm square W, Mo, and TEOS (silicon dioxide) wafers and the polishing conditions of Example 1. The following Table 11 provides the formulations at 2.5.

[0079]

Table 20

[0080]

Table 21

[0081]

Table 22

[0082] These data are combined to show that molybdic acid in combination with silica polishing particles does not increase the tungsten removal rate. However, molybdic acid was effective in increasing the removal rate when combined with hybrid carbon particles.

[0083] Example 12 A series of wafers were compared using 2.6 cm × 2.6 cm square W, Mo, and TEOS (silicon dioxide) wafers and the polishing conditions of Example 1. The following Table 12 provides the formulations at 2.5.

[0084]

Table 23

[0085]

Table 24

[0086] These data show that molybdic acid, tungstic acid, and vanadate all increase the removal rates of tungsten and molybdenum with both hybrid carbon particles and SiC particles.

[0087] Example 13 A series of wafers were compared using W, Mo, and TEOS (silicon dioxide) wafers with a 2.6 cm × 2.6 cm angle and the polishing conditions of Example 1. Table 13 below provides the formulation at pH 2.5.

[0088]

Table 25

[0089]

Table 26

[0090] These data indicate that all molybdic acid and its derivatives increase the tungsten removal rate without increasing the TEOS removal rate.

[0091] Example 14 This example provides an example of a dispersant for hybrid carbon particles at pH 3 using nitric acid as a titrant.

[0092]

Table 27

[0093]

Table 28

[0094] These data indicate that a polymer dispersant containing a -C(=O)-NH- moiety can reduce the particle sedimentation rate.

[0095] Example 15 Table 15 below shows, in weight percent, the formulation for particle stability using abrasive 2-2 for hybrid-structured carbon particles containing 0.01 wt% of molybdic acid and 0.3 wt% using a nitric acid titrant.

[0096]

Table 29

[0097]

Table 30

[0098]

Table 31

[0099] These data indicate that the polymer dispersant containing the -C(=O)-NH- moiety can reduce the particle sedimentation rate.

[0100] Example 16 The following Table 16 provides formulations for static etching control using a nitric acid titrant at pH 3 with 0.01 wt% of the hybrid structure carbon particle abrasive 2-2 and 0.3 wt% of molybdic acid (excluding AL).

[0101] 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 etching rate (Å / min) was calculated by (wafer thickness after etching - wafer thickness before etching) / 3.

[0102]

Table 32

[0103]

Table 33

[0104] These data indicated that in the presence of molybdic acid, anionic and nonionic polymers do not function as corrosion inhibitors to control the static etching rate of tungsten. However, cationic nitrogen-containing polymers can reduce the static etching rate of tungsten to a low level. In particular, these polymers can achieve a reduction exceeding 50% of the static etching rate.

[0105] Example 17 All samples contained 1 μM of terephthalic acid and were injected into ultra-high performance liquid chromatography immediately after mixing with the specified amount of hydrogen peroxide. Hydroxyterephthalic acid ("HPA"), the expected final product, was used to reflect the amount of hydroxyl radical formation. HPA was identified (the effluent peak was measured at an initial interval of 5.1 minutes and subsequent intervals of 4.5 minutes). These peaks were then quantified by mass spectral extracted ion chromatograms.

[0106] The reaction of hydroxyl radicals with HPA is as follows:

Chemical formula

[0107]

Table 34

[0108] Fenton-containing samples promoted the formation of hydroxyl radicals. Unlike the Fenton-containing examples, functionalized carbon-based particles without Fenton did not promote the formation of hydroxyl radicals. Specifically, Fenton-free samples did not detect the presence of hydroxyl radicals. Similarly, molybdic acid-containing samples did not promote significant formation of hydroxyl radicals.

Claims

Claim 1 A chemical mechanical polishing liquid for a tungsten-containing substrate, comprising: an aqueous solvent; functionalized carbon-based particles having oxygen-containing functional groups, wherein the functionalized carbon-based particles having oxygen-containing functional groups react with a peroxide moiety to increase the oxygen-to-carbon atom ratio on the functionalized carbon-based particles, the functionalized carbon-based particles contain at least 10 wt% of an sp3-containing structure, the functionalized carbon-based particles contain at least 0.01 atomic % of oxygen, and the surface of the functionalized carbon-based particles has an atomic oxygen-to-carbon ratio of at least 0.01; and a nitrogen-containing cationic polymer of 1 ppm to 1000 ppm for reducing the static etching rate of the tungsten-containing substrate by the polishing liquid A chemical mechanical polishing liquid comprising the above. Claim 2 The polishing liquid according to Claim 1, further comprising a corrosion inhibitor for the metal or the metal nitride. Claim 3 The polishing liquid according to Claim 1, wherein the surface of the functionalized carbon-based particles comprises graphene, graphite, amorphous carbon, or a mixture thereof. Claim 4 The polishing liquid according to Claim 1, wherein the oxygen-containing functional groups are COOH and its salts, COOOH and its salts, OH-, ketone, oxirane, or a combination thereof. Claim 5 The functionalized carbon-based particles also contain an amine (NH ２ ), sulfonate (SO ３ ) group or hydrocarbon (C-H) group, and the polishing liquid according to claim 4. Claim 6 The polishing liquid according to Claim 1, wherein the metal and the metal nitride are selected from the group consisting of cobalt, copper, molybdenum, tungsten, titanium nitride, and tantalum nitride. Claim 7 The polishing liquid according to Claim 1, wherein the peroxide moiety contains hydrogen peroxide. Claim 8 The polishing liquid according to Claim 1, comprising a Fenton catalyst or reagent and containing at least 0.5 μM of hydroxyl radicals. Claim 9 The polishing liquid according to Claim 1, wherein the polishing liquid does not contain iron and contains less than 0.01 μM of hydroxyl radicals. Claim 10 The polishing liquid according to Claim 1, wherein the functionalized carbon-based particles contain at least 30 wt% of an sp3-containing structure.

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