Compositions and methods for dielectric CMP

Abstract

A chemical mechanical polishing composition for polishing a substrate having a silicon-oxygen material comprises, consists of, or consists essentially of a liquid carrier, cubic ceria abrasive particles dispersed in the liquid carrier, and a cationic polymer having a charge density greater than about 6 meq / g.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 924,328, filed October 22, 2019, entitled "Composition and Method for Dielectric CMP." [Background technology]

[0002] Chemical mechanical polishing is an important enabling technology in integrated circuit (IC) and microelectromechanical systems (MEMS) fabrication. CMP compositions and methods for polishing (or planarizing) the surface of a substrate (e.g., a wafer) are well known in the art. Polishing compositions (also known as polishing slurries, CMP slurries, and CMP compositions) generally contain abrasive particles suspended (dispersed) in an aqueous solution, as well as chemical additives to increase the material removal rate, improve planarization efficiency, and / or reduce the defectivity during the CMP operation.

[0003] Cerium oxide (ceria) abrasives are well known in the industry, particularly for polishing silicon-containing substrates, including, for example, silicon oxide materials such as tetraethyl orthosilicate (TEOS), silicon nitride, and / or polysilicon. Ceria abrasive compositions are commonly used in high-performance dielectric applications, including, for example, shallow trench isolation applications. While the use of ceria abrasives is known, there remains a need for improved ceria abrasive-based CMP compositions. In particular, there remains a need for CMP compositions that provide improved removal rates and improved planarization (e.g., reduced corrosion and dishing). Furthermore, there remains a need for compositions that provide removal rate selectivity for one silicon-containing substrate versus another (e.g., silicon oxide versus silicon nitride selectivity or silicon oxide versus polysilicon selectivity). Summary of the Invention

[0004] A chemical-mechanical polishing composition for polishing a substrate having a silicon-oxygen material (e.g., silicon oxide) is disclosed. In one embodiment, the polishing composition comprises, consists of, or consists essentially of a liquid carrier, cubic ceria abrasive particles dispersed in the liquid carrier, and a cationic polymer having a charge density greater than about 6 milliequivalents per gram (meq / g).

[0005] For a more complete understanding of the disclosed subject matter, and its advantages, reference is now made to the following detailed description taken in conjunction with the accompanying figures. [Brief explanation of the drawings]

[0006] [Figure 1] 1 shows a transmission electron microscope (TEM) photograph of a cubic ceria abrasive sample showing ceria abrasive particles with square faces. [Figure 2] 1 shows a transmission electron microscope (TEM) photograph of a cubic ceria abrasive sample showing ceria abrasive particles with square faces. [Figure 3] 1 shows a scanning electron microscope (SEM) photograph of a cubic ceria abrasive sample showing ceria abrasive particles with square faces. DETAILED DESCRIPTION OF THE INVENTION

[0007] A chemical-mechanical polishing composition for polishing a substrate having a silicon-oxygen material (e.g., silicon oxide) is disclosed. The polishing composition comprises, consists of, or consists essentially of a liquid carrier, cubic ceria abrasive particles dispersed in the liquid carrier, and a cationic polymer having a charge density greater than about 6 milliequivalents per gram (meq / g). The cationic polymer may include, for example, ε-polylysine and / or poly(vinylimidazolium).

[0008] The disclosed polishing compositions and corresponding (CMP) methods can provide significant unexpected advantages. For example, the disclosed compositions can provide significantly improved silicon oxide removal rates, thereby improving throughput and saving time and money. In certain embodiments, the disclosed compositions can also provide reduced silicon nitride removal rates and significantly improved silicon oxide to polysilicon selectivity. The disclosed compositions can also provide improved dishing and erosion across a wide range of pattern features and densities.

[0009] The polishing composition contains abrasive particles comprising cubic cerium oxide abrasive particles suspended in a liquid carrier. By "cubic," it is intended that the ceria abrasive particles be in the form or shape of a cube, i.e., substantially cubic. Stated differently, the cubic ceria abrasive particles are cubic in form or nature. However, it will be understood that the edge dimensions, corners, and corner angles need not be exactly or precisely those of a perfect cube. For example, cubic abrasive particles may have slightly rounded or chipped corners, slightly rounded edges, edge dimensions that are not exactly equal to one another, corner angles that are not exactly 90 degrees, and / or other minor irregularities and still retain a basic cubic morphology. One skilled in the art will readily recognize (e.g., via scanning electron microscopy or transmission electron microscopy) that cubic ceria abrasive particles are cubic in form within generally accepted tolerances for particle growth and deagglomeration.

[0010] Figures 1, 2, and 3 show exemplary cubic ceria abrasive particles. These transmission electron microscope (TEM) and scanning electron microscope (SEM) images show ceria abrasive particles with square faces. For example, in these images, the particle faces shown each include four edges that have substantially the same length (e.g., within 20 percent of each other, or even within 10 percent of one another). Furthermore, these edges meet at corners at approximately 90-degree angles (e.g., within about 80-100 degrees, or about 85-95 degrees). Those skilled in the art will readily appreciate that a significant majority of the abrasive particles shown in the TEM and SEM images are cubic in that they have square faces as defined above. Some of the particles may be observed to contain defects, for example, at one or more corners. It will also be understood that the term cubic is intended to describe ceria abrasive particles that are not precisely cubic, but rather particles that are generally cubic in nature, as described above and shown in Figures 1, 2, and 3.

[0011] As used herein, a chemical-mechanical polishing composition containing a cubic ceria abrasive is one in which at least 25 number percent of the abrasive particles are essentially cubic (cubic in form or shape, as described above). In a preferred embodiment, at least 40 number percent (e.g., at least 60 percent, or at least 80 percent) of the abrasive particles are essentially cubic. As described above, cubic ceria abrasive particles can be easily evaluated and counted using TEM or SEM images, for example, at magnifications ranging from about 10,000x to about 500,000x. SEM or TEM images show abrasive particles with four sides having similar lengths (e.g., within 20 percent of each other, as described above). Such images also show that adjacent sides are generally perpendicular, forming angles of, for example, about 90 degrees (e.g., in the range of about 80 to about 100 degrees, as also shown above). To determine whether a ceria abrasive composition contains cubic ceria abrasive particles, SEM or TEM observations will be made on a large number of randomly selected particles (i.e., greater than 200) so that statistical analysis can be performed to determine the percentage of particles with square faces. Retained particles should be such that their images are clearly visible in the photograph. Some of the particles may exhibit some defects either on their surface and / or at one or more of their corners and still be counted as cubic.

[0012] The cubic ceria abrasive particles may be substantially pure ceria abrasive particles (within normal tolerances for impurities) or doped ceria abrasive particles. Doped ceria abrasive particles may contain interstitial dopants (dopants occupying spaces in the lattice that are not normally occupied) or substitutional dopants (dopants occupying spaces in the lattice that are normally occupied by cerium or oxygen atoms). Such dopants may include virtually any metal atom, including, for example, Ca, Mg, Zn, Zr, Sc, or Y.

[0013] In certain advantageous embodiments, the dopant may include one or more lanthanides, including, for example, lanthanum, praseodymium, neodymium, promethium, samarium, and the like. In one particularly preferred embodiment, the cubic ceria abrasive particles include a mixed oxide of cerium and lanthanum. The mixed oxide abrasive particles may have a molar ratio of La to (La+Ce) within the range of about 0.01 to about 0.15, e.g., about 0.01 to about 0.12. It will be understood that such abrasive particles may additionally contain other elements and / or oxides (e.g., as impurities). Such impurities may originate from raw materials or starting materials used in the process of preparing the abrasive particles. The total percentage of impurities is preferably less than 0.2% by weight of the particles. Residual nitrates are not considered impurities.

[0014] In certain embodiments, the molar ratio of La to (La+Ce) may be in the range of about 0.01 to about 0.04 (e.g., about 0.02 to about 0.03). In one such embodiment, the cubic ceria abrasive particles contain about 2.5 mole percent lanthanum oxide and about 97.5 mole percent cerium oxide. In other embodiments, the molar ratio may be in the range of about 0.08 to about 0.12 (e.g., about 0.09 to about 0.11). In one such embodiment, the cubic ceria abrasive particles contain about 10 mole percent lanthanum oxide and about 90 mole percent cerium oxide. The abrasive particles may be a single-phase solid solution in which lanthanum atoms substitute for cerium atoms in the cerium oxide crystalline structure. In one embodiment, the solid solution exhibits a symmetrical x-ray diffraction pattern with peaks between about 27 degrees and about 29 degrees, which are shifted to lower angles than pure cerium oxide. A solid solution can be obtained when the temperature of the aging substep (described below) exceeds about 60°C (333K). As used herein, the term "solid solution" means that x-ray diffraction shows only the pattern of the cerium oxide crystal structure, with or without shifts of individual peaks, but without additional peaks that may indicate the presence of other phases.

[0015] The cubic ceria abrasive particles may optionally be characterized by their specific surface area, as determined on the powder by nitrogen adsorption using the Brunauer-Emmett-Teller (BET) method. This method is disclosed in ASTM D3663-03 (reapproved in 2015). The abrasive particles have a specific surface area of ​​about 3 to about 14 m. 2 / g (e.g., about 7 to about 13 m 2 / g or about 8 to about 12m 2 / g).

[0016] The cubic ceria abrasive particles may optionally be characterized by their average particle size and / or particle size distribution. The abrasive particles may have an average particle size within a range of about 50 nm to about 1000 nm (e.g., about 80 nm to about 500 nm, about 80 nm to about 250 nm, about 100 nm to about 250 nm, or about 150 nm to about 250 nm). The average particle size may also be greater than about 50 nm (e.g., greater than about 80 nm or greater than about 100 nm). The average particle size may be determined via dynamic light scattering (DLS) and corresponds to the median particle size (D50). DLS measurements may be performed, for example, using a Zetasizer (available from Malvern Instruments). Those skilled in the art will readily recognize that DLS measurements, when performed in the presence of relatively larger particles, may significantly undercount small particles. For the cubic ceria abrasive particles disclosed herein, DLS techniques tend to undercount particles less than about 40 nm, and it will be understood that the disclosed embodiments may include significant amounts of such small particles (less than 40 nm) that are not counted by DLS and therefore do not contribute to the average particle size.

[0017] Laser diffraction techniques may optionally be used to characterize the particle size distribution. Those skilled in the art will readily recognize that laser diffraction techniques also tend to undercount small particles (e.g., less than 40 nm in the disclosed embodiments). Laser diffraction measurements may be performed, for example, using a Horiba LA-960 spectrometer using a relative refractive index of 1.7. Various parameters, including, for example, D10, D50, D90, D99, and the dispersion index (defined below), may be obtained from the distribution obtained by laser diffraction measurements. Based on laser diffraction measurements, the abrasive particles may have a median diameter (D50) in the range of about 100 nm to about 700 nm (e.g., about 100 nm to about 200 nm). For example, D50 may be in the range of about 100 nm to about 150 nm, or about 150 nm to about 200 nm. D50 is the median diameter determined from the distribution obtained by laser diffraction.

[0018] The cubic ceria abrasive particles can optionally have a D10 in the range of about 80 nm to about 400 nm (e.g., about 80 nm to about 250 nm, about 80 nm to about 150 nm, or about 100 nm to about 130 nm). It is understood that D10 represents the particle size obtained by laser diffraction at which 10% of the particles have a diameter less than D10.

[0019] The cubic ceria abrasive particles may optionally have a D90 in the range of about 150 nm to about 1200 nm (e.g., about 150 nm to about 1000 nm, about 150 to about 750 nm, about 150 to about 500 nm, about 150 to about 300 nm, or about 200 nm to about 300 nm). D90 represents the particle size determined by laser diffraction at which 90% of the particles have a diameter less than D90. Abrasive particles that have undergone mechanical deagglomeration may have a D90 of less than about 300 nm.

[0020] The cubic ceria abrasive particles may optionally exhibit a low dispersion index. "Dispersion index" is defined by the following formula: Dispersion index = (D90 - D10) / 2 D50. The dispersion index may be less than about 0.60, such as less than about 0.5, less than about 0.4, or less than about 0.30. Abrasive particles that have undergone mechanical deagglomeration may have a dispersion index of less than about 0.30. Additionally, D90 / D50 may be in the range of about 1.3 to about 2 for particles that have undergone mechanical deagglomeration.

[0021] The cubic ceria abrasive particles may optionally have a D99 in the range of about 150 nm to about 3000 nm (e.g., about 200 nm to about 2000 nm, about 200 nm to about 1800 nm, about 200 to about 1200 nm, about 200 to about 900 nm, about 200 nm to about 600 nm, about 200 to about 500 nm, or about 200 to about 400 nm). Abrasive particles that have undergone mechanical deagglomeration may have a D99 of less than about 600 nm (e.g., less than about 500 or less than about 400). D99 represents the particle size determined by laser diffraction where 99% of the particles have a diameter less than D99.

[0022] The abrasive particles may be prepared using virtually any suitable method for producing cubic ceria abrasive particles. The disclosed embodiments are directed to chemical-mechanical polishing compositions containing such abrasive particles and methods for polishing a substrate using such abrasive particles, and are not limited to any particular method for producing the particles. In certain embodiments, cubic ceria abrasive particles may be prepared by precipitating cerium nitrate (and, optionally, other nitrates when doped ceria abrasives are prepared). The precipitated material may then be grown under specific temperature and pressure regimes to promote the growth of cubic ceria abrasive particles. These particles may then be cleaned and deagglomerated. A dispersion of cubic ceria abrasive particles may then be prepared and used to formulate the chemical-mechanical composition of the present invention.

[0023] In one advantageous embodiment, cubic lanthanum cerium oxide abrasive particles can be prepared by precipitating cerium nitrate and lanthanum nitrate. One such preparation method includes the following steps: (i) Under an inert atmosphere, an aqueous solution of cerium nitrate and an aqueous base are mixed. (ii) heating the mixture obtained in (i) under an inert atmosphere; (iii) The heat treated mixture obtained in (ii) is optionally acidified. (iv) Washing the solid material obtained in (ii) or (iii) with water. (v) The solid material obtained in (iv) is mechanically treated to deagglomerate the ceria particles.

[0024] The cerium nitrate solution used in step (i) of the above method may be prepared by mixing aqueous solutions of cerium nitrate and lanthanum nitrate. III , Ce IV and La III Contains Ce IV It may be characterized by a molar ratio of Ce to total Ce of between about 1 / (500,000) and about 1 / (4,000). In one example embodiment, the molar ratio may be between about 1 / (100,000) and about 1 / (90,000). It is generally advantageous to use salts and components with high purity, for example, at least 99.5 weight percent or even 99.9 weight percent purity.

[0025] Step (i) involves mixing / reacting an aqueous cerium nitrate solution with an aqueous base. For example, hydroxide-type bases, including alkali metal or alkaline earth metal oxides and aqueous ammonia, may be advantageous. Secondary, tertiary, or quaternary amines may also be used. The aqueous base solution may be degassed (deoxygenated) beforehand by bubbling with an inert gas. Mixing may be carried out by introducing the aqueous cerium nitrate solution into the aqueous base, and is advantageously carried out under an inert atmosphere, for example, in a closed or semi-closed reactor with an inert gas (e.g., nitrogen or argon). Mixing may be carried out with stirring. The molar ratio of the base pair (Ce+La) may be between about 8.0 and about 30.0 (e.g., greater than about 9.0). Step (i) may further be carried out at a temperature between about 5°C (278 K) and about 50°C (323 K), for example, between about 20°C (293 K) and 25°C (298 K).

[0026] Step (ii) involves heating the mixture obtained at the end of the previous step and may include a heating substep and an aging substep. The heating substep may involve heating the mixture to a temperature in the range of about 75°C (348K) to about 95°C (368K), for example, about 85°C (358K) to about 90°C (363K). The aging substep may involve maintaining (holding) the mixture at the temperature for a duration in the range of about 2 hours to about 20 hours. Generally, the aging time decreases with increasing temperature. Step (ii) may be carried out under an inert atmosphere and stirring as described above for step (i).

[0027] In step (iii), the mixture obtained at the end of step (ii) may be optionally acidified, for example, using nitric acid. The heat-treated reaction mixture may be acidified, for example, to a pH of less than about 3.0 (e.g., in the range of about 1.5 to about 2.5).

[0028] In step (iv), the solid material obtained in step (ii) or (iii) may be washed with water (e.g., deionized water). Washing may be used to reduce the remaining nitrates in the final dispersion to achieve the target conductivity. Washing may include filtering the solid from the mixture and redispersing the solid in water. Filtration and redispersion may be performed several times, if necessary.

[0029] In step (v), the washed solid material obtained in (iv) may optionally be mechanically treated to deagglomerate or partially deagglomerate the ceria abrasive particles. Mechanical treatment may include, for example, double-jet processing or ultrasonic deagglomeration, and typically results in a narrow particle size distribution and a reduced number of large agglomerated particles.

[0030] After step (iv) or (v), the solid material may be dried to obtain the cerium-based particles in powder form. The powder may be redispersed by adding water or a mixture of water and a miscible liquid organic compound to obtain a dispersion of the cerium-based particles in the liquid medium. The liquid medium may be water or a mixture of water and a water-miscible organic liquid. The water-miscible organic liquid may include alcohols such as propyl alcohol, ethanol, 1-propanol, methanol, and 1-hexanol; ketones such as acetone, diacetone alcohol, and methyl ethyl ketone; and esters such as ethyl formate, propyl formate, ethyl acetate, methyl acetate, methyl lactate, butyl lactate, and ethyl lactate. The ratio of water to organic liquid may be between 80 and 20 parts by weight and 99 and 1 parts by weight. The dispersion may also contain about 1 weight percent to about 40 weight percent, e.g., about 10 weight percent to about 35 weight percent, of the cerium-based particles. The dispersion may have a conductivity of less than about 300 μS / cm, such as less than about 150, more particularly less than 150 μS / cm, or less than about 100 μS / cm.

[0031] The polishing composition may contain substantially any suitable amount of cubic ceria abrasive particles. For example, the polishing composition may contain about 0.0001 weight percent (1 ppm by weight) or more (e.g., about 0.001 weight percent or more, about 0.005 weight percent or more, about 0.01 weight percent or more, about 0.02 weight percent or more, about 0.05 weight percent or more, or about 0.1 weight percent or more) of cubic ceria abrasive particles at the time of use. The polishing composition may contain about 10 weight percent or less (e.g., about 5 weight percent or less, about 2 weight percent or less, about 1.5 weight percent or less, about 1 weight percent or less, about 0.5 weight percent or less, or about 0.2 weight percent or less) of cubic ceria abrasive particles at the time of use. It will be understood that the cubic ceria abrasive particles may be present in the polishing composition at a concentration bounded by any two of the above endpoints. For example, the concentration of cubic ceria abrasive particles in the polishing composition at the time of use may be in the range of about 0.0001 weight percent to about 10 weight percent (e.g., about 0.001 weight percent to about 1 weight percent, about 0.005 weight percent to about 1 weight percent, about 0.005 weight percent to about 0.5 weight percent, or about 0.005 weight percent to about 0.2 weight percent).

[0032] The aqueous liquid carrier is used to facilitate application of the abrasive and any optional chemical additives to the surface of the substrate to be polished (e.g., planarized). By aqueous, it is meant that the liquid carrier is composed of at least 50% by weight of water (e.g., deionized water). The liquid carrier may include other suitable non-aqueous carriers, including, for example, lower alcohols (e.g., methanol, ethanol, etc.) and ethers (e.g., dioxane, tetrahydrofuran, etc.). Preferably, the liquid carrier consists essentially of, or consists of, water, more preferably deionized water.

[0033] The polishing composition is generally acidic or weakly acidic, having a pH of less than about 7. The polishing composition may have a pH of about 2 or greater (e.g., about 3 or greater, or about 3.5 or greater). The polishing composition may also have a pH of about 7 or less (e.g., about 6 or less, or about 5 or less). It will be understood that the polishing composition may have a pH within a range bounded by any two of the above endpoints, e.g., from about 2 to about 7 (e.g., from about 3 to about 6, from about 3 to about 5, or from about 3.5 to about 5). For example, in certain embodiments, the pH of the composition may be about 4. In other embodiments, the pH of the composition may be about 5.

[0034] The polishing composition further comprises a cationic polymer, which may include virtually any suitable cationic polymer, such as a cationic homopolymer, a cationic copolymer comprising at least one cationic monomer (and optionally a nonionic monomer), and combinations thereof.

[0035] The cationic polymer may be virtually any suitable cationic homopolymer containing cationic monomer repeat units, for example, quaternary amine groups as repeat units. The quaternized amine group may be acyclic or incorporated into a ring structure. The quaternized amine group comprises a four-substituted nitrogen atom substituted by four groups independently selected from alkyl, alkenyl, aryl, arylalkyl, acrylamide, or methacrylate groups. When contained in a ring structure, the quaternized amine group comprises either a heterocyclic saturated ring containing the nitrogen atom and further substituted by two groups described above, or a heteroaryl group (e.g., imidazole or pyridine) having additional groups described above attached to the nitrogen atom. The quaternized amine group carries a positive charge (i.e., it is a cation that has an associated anionic moiety and thereby forms a salt). The cationic polymer may also be further modified by alkylation, acylation, ethoxylation, or other chemical reaction to alter the solubility, viscosity, or other physical parameters of the cationic polymer. Suitable quaternary amine monomers include, for example, quaternized vinylimidazole (vinylimidazolium), methacryloyloxyethyltrimethylammonium (MADQUAT), diallyldimethylammonium (DADMA), methacrylamidopropyltrimethylammonium (MAPTA), quaternized dimethylaminoethyl methacrylate (DMAEMA), epichlorohydrin-dimethylamine (epi-DMA), cationic poly(vinyl alcohol) (PVOH), quaternized hydroxyethyl cellulose, and combinations thereof. It will be recognized that MADQUAT, DADMA, MAPTA, and DMAEMA generally include a counteranion, such as a carboxylate (e.g., acetate) or halide anion (e.g., chloride). The disclosed embodiments are not limited in this respect.

[0036] The cationic polymer may be a copolymer comprising at least one cationic monomer (e.g., as described in the preceding paragraph) and at least one nonionic monomer. Non-limiting examples of suitable nonionic monomers include vinylpyrrolidone, vinylcaprolactam, vinylimidazole, acrylamide, vinyl alcohol, polyvinyl formal, polyvinyl butyral, poly(vinyl phenyl ketone), vinylpyridine, polyacrolein, cellulose, hydroxyethyl cellulose, ethylene, propylene, styrene, and combinations thereof.

[0037] Exemplary cationic polymers include, but are not limited to, poly(vinylimidazolium), poly(methacryloyloxyethyltrimethylammonium) (polyMADQUAT), poly(diallyldimethylammonium) (e.g., polyDADMAC) (i.e., Polyquaternium-6), poly(dimethylamine-co-epichlorohydrin), poly[bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] (i.e., Polyquaternium-2), copolymers of hydroxyethyl cellulose and diallyldimethylammonium (i.e., Polyquaternium-4), copolymers of acrylamide and diallyldimethylammonium (i.e., Polyquaternium-7), quaternized cellulose, and the like. Examples of suitable copolymers include hydroxyethylcellulose ethoxylate (i.e., Polyquaternium-10), copolymers of vinylpyrrolidone and quaternized dimethylaminoethyl methacrylate (i.e., Polyquaternium-11), copolymers of vinylpyrrolidone and quaternized vinylimidazole (i.e., Polyquaternium-16), Polyquaternium-24, terpolymers of vinylcaprolactam, vinylpyrrolidone, and quaternized vinylimidazole (i.e., Polyquaternium-46), 3-methyl-1-vinylimidazolium methylsulfate-N-vinylpyrrolidone copolymer (i.e., Polyquaternium-44), and copolymers of vinylpyrrolidone and diallyldimethylammonium. Additionally, suitable cationic polymers include personal care cationic polymers such as Luviquat® Supreme, Luviquat® Hold, Luviquat® UltraCare, Luviquat® FC370, Luviquat® FC550, Luviquat® FC552, Luviquat® Excellence, GOHSEFIMER K210™, GOHSENX K-434, and combinations thereof.

[0038] In certain embodiments, the cationic polymer may comprise amino acid monomers (such compounds are sometimes referred to as polyamino acid compounds). Suitable polyamino acid compounds may comprise virtually any suitable amino acid monomer group, including, for example, polyarginine, polyhistidine, polyalanine, polyglycine, polytyrosine, polyproline, and polylysine. In certain embodiments, polylysine is a preferred polyamino acid. It will be understood that polylysine may include ε-polylysine and / or α-polylysine, which are composed of D-lysine and / or L-lysine. Polylysine may therefore include α-poly-L-lysine, α-poly-D-lysine, ε-poly-L-lysine, ε-poly-D-lysine, and mixtures thereof. In certain embodiments, the polylysine may be ε-poly-L-lysine. It will further be understood that the polyamino acid compound(s) may be used in any available form, e.g., conjugate acid or base, and that salt forms of the polyamino acids may be used in place of (or in addition to) the polyamino acids.

[0039] The cationic polymer may also (or alternatively) comprise a derivatized polyamino acid (i.e., a cationic polymer containing derivatized amino acid monomer units). For example, the derivatized polyamino acid may comprise a derivatized polyarginine, a derivatized polyornithine, a derivatized polyhistidine, and a derivatized polylysine. CMP compositions comprising derivatized polyamino acid compounds are disclosed in U.S. Provisional Patent Application No. 62 / 958,033, the entire contents of which are incorporated herein by reference.

[0040] In such embodiments, the derivatized amino acid monomer comprises a derivative group attached to the alpha amino group of the derivatized amino acid monomer, which may comprise virtually any suitable group, including, for example, alkylcarbonyl groups, divalent carboacyl groups, alkylurea groups, alkylsulfonate groups, alkylsulfone groups, and alkyl ester groups.

[0041] Exemplary alkylcarbonyl groups include acetyl, pivaloyl, ethylcarbonyl, and the like. Exemplary divalent carboacyl groups include succinyl, octenylsuccinyl, glutaric acid, methylsuccinyl, and the like. Among the divalent carboacyl groups, succinyl and glutaric acid may be preferred due to solubility. Exemplary alkylurea groups include ethylurea, butylurea, cyclohexylurea, and the like. Exemplary alkylsulfonate groups include methylsulfonate, dimethylsulfonate, ethylsulfonate, propylsulfonate, butylsulfonate, pentasulfonate, and the like. Exemplary alkylsulfone groups include methylsulfone, ethylsulfone, propylsulfone, butylsulfone, pentasulfone, and the like. Exemplary alkyl ester groups include methyl ester, ethyl ester, propyl ester, butyl ester, pentaester, and the like.

[0042] The most preferred derivatized polyamino acids include succinylated epsilon polylysine (derivatized polylysine in which the derivative group is a succinyl group).

[0043] The cationic polymer can have virtually any suitable molecular weight. For example, the cationic polymer can have an average molecular weight of about 200 g / mol or more (e.g., about 500 g / mol or more, about 1,000 g / mol or more, about 2,000 g / mol or more, about 5,000 g / mol or more, or about 10,000 g / mol or more). The cationic polymer can have an average molecular weight of about 5,000,000 g / mol or less (e.g., about 2,000,000 g / mol or less, about 1,000,000 g / mol or less, about 800,000 g / mol or less, about 600,000 g / mol or less, or about 500,000 g / mol or less). It will therefore be understood that the cationic polymer can have an average molecular weight bounded by any two of the above endpoints. For example, the cationic polymer may have an average molecular weight of about 200 g / mol to about 5,000,000 g / mol (eg, about 1,000 g / mol to about 2,000,000 g / mol, or about 2,000 g / mol to about 2,000,000 g / mol).

[0044] In the first group of disclosed polishing compositions, the cationic polymer can be characterized as having a high charge density (e.g., greater than about 6 meq / g). In the second group of disclosed polishing compositions, the cationic polymer can be characterized as having a low charge density (e.g., less than about 6 meq / g).

[0045] The charge density of a polymer can be defined as the number of charges per average molecular weight of the monomer repeat unit(s). Charge density can be calculated for many polymers when the molecular structure of the monomers is known, as well as for copolymers when the molar ratio of the monomers is known. As used herein, charge density is expressed in units of milliequivalents per gram (meq / g) and is calculated by dividing the number of charges by the average molecular weight of the monomer repeat unit(s) and multiplying by 1000, as follows for a homopolymer:

number

[0046] where CD represents the charge density of the polymer and MW モノマー where q is the molecular weight of the monomer and q is the number of charges per monomer unit (typically 1). For example, a hypothetical homopolymer whose monomers have a single positive charge and a molecular weight of 120 g / mol has a charge density of 8.3 (i.e., 1000 1 / 120).

[0047] More broadly, the charge density of virtually any polymer (e.g., copolymers, terpolymers, etc.), including those with more than one monomer unit, can be expressed mathematically, for example, as follows:

number

[0048] For purposes of this disclosure, as described above, the charge density of cationic homopolymers is calculated using Equation (1), and the charge density of cationic copolymers, terpolymers, etc. is calculated using Equation (2). Those skilled in the art will readily recognize that certain cationic polymers contain corresponding counteranions (e.g., chloride ions, as in poly(methacryloyloxyethyltrimethylammonium) chloride or poly(diallyldimethylammonium) chloride) associated with the cationic monomer units. While such counteranions may affect the functionality of the polymer, it will be understood that, for purposes of this disclosure, the molecular weight of such counteranions is not included in the calculation of charge density. In other words, the charge density is calculated without considering the molecular weight of any counteranions (if present). For example, in poly(diallyldimethylammonium) chloride, the molecular weight of the diallyldimethylammonium monomer is approximately 126.1, resulting in a charge density of approximately 7.93 using Equation 1.

[0049] In a particular cationic polymer (or terpolymer, etc.), the molar ratios of the monomers are unknown (i.e., n1, n2,...n x (At least one of the unknowns in Equation 2 is unknown). The charge density of such cationic polymers can be determined through measurements using polyvinyl sulfate potassium salt (PVSK) titration with toluidine blue dye, which is sensitive to the ionic nature of the solution. In such measurements, a PVSK solution is titrated to the endpoint in an aqueous cationic polymer solution containing the blue dye. In such titrations, the solution starts out dark blue and turns pink in the presence of excess PVSK (i.e., when all the cationic polymer in the solution has bound with PVSK). Those skilled in the art will readily understand that the color change (to pink) indicates the end of the titration. The volume of the PVSK titrant is recorded and used to calculate the charge density of the polymer. The titration is preferably performed three times to ensure adequate accuracy. PVSK titrations are described in more detail in Example 7.

[0050] For purposes of this disclosure, titrations of cationic polymers of unknown structure are compared to identical titrations performed on polymers of known structure (preferably polyquaternium-7). A first volume (or mass) of PVSK titrant V1 is obtained when titrating a solution containing a cationic polymer of known structure (polyquaternium-7). A second volume (or mass) of PVSK titrant V2 is obtained when titrating a solution containing a cationic polymer of unknown structure. Relative charge densities (e.g., relative to polyquaternium-7) CD R is defined as the ratio of titrant volume (or mass) as follows:

number

[0051] The measured charge density (CD2) of a cationic polymer with unknown structure is calculated relative to the charge density CD of a cationic polymer with known structure (Polyquaternium-7) as follows: R and the calculated charge density:

number

[0052] PVSK titration is described in more detail in Example 7. Also, the above procedure for determining the relative charge density and charge density of cationic polymers of unknown structure is described in more detail for a number of cationic polymers in Example 7.

[0053] A first group of the disclosed compositions may include a cationic polymer having a charge density greater than about 6 meq / g (e.g., greater than about 7 meq / g, greater than about 8 meq / g, or greater than about 9 meq / g).

[0054] Exemplary high charge density cationic polymers include poly(vinylimidazole), poly(vinylimidazolium), poly(vinylmethylimidazolium), such as poly(vinylmethylimidazolium) and poly(vinylmethylimidazolium) methyl sulfate, epichlorohydrin-dimethylamine, polydiallyldimethylammonium (e.g., polyDADMAC), polyethyleneimine, polyarginine, polyhistidine, and ε-polylysine. In certain embodiments, the high charge density cationic polymer may comprise poly(vinylimidazolium) or ε-polylysine. Table 1 lists the charge densities (meq / g) of each of the above-listed cationic polymers using Formulas 1 and / or 2. Table 1 [Table 1]

[0055] Polishing compositions containing high charge density cationic polymers generally contain low concentrations of high charge density cationic polymers at the time of use. For example, the polishing composition may contain less than about 50 ppm by weight (e.g., less than about 25 ppm by weight, less than about 20 ppm by weight, less than about 15 ppm by weight, less than about 12 ppm by weight, or less than about 10 ppm by weight) of high charge density cationic polymer at the time of use. Such polishing compositions may contain more than about 0.1 ppm by weight (e.g., more than about 0.2 ppm by weight, more than about 0.5 ppm by weight, more than about 0.8 ppm by weight, or more than about 1 ppm by weight) of high charge density cationic polymer at the time of use. It will be understood that the high charge density cationic polymer may be present in the polishing composition at a concentration bounded by any two of the above endpoints. For example, the polishing composition may contain from about 0.1 ppm to about 50 ppm by weight (e.g., from about 0.5 ppm to about 25 ppm by weight, from about 1 ppm to about 20 ppm by weight, or from about 1 ppm to about 15 ppm by weight) of high charge density cationic polymer at the time of use.

[0056] The polishing composition containing the high charge density cationic polymer may further contain a silicon oxide polishing rate enhancer (i.e., a compound that increases the removal rate of silicon oxide (e.g., TEOS or HDP)). Suitable polishing rate enhancers may include, for example, carboxylic acid compounds that activate the substrate. Exemplary rate enhancers include, for example, picolinic acid, nicotinic acid, quinaldic acid, isonicotinic acid, acetic acid, and 4-hydroxybenzoic acid. In certain advantageous embodiments (and certain exemplary embodiments disclosed below), the rate enhancer includes picolinic acid, acetic acid, or a mixture thereof.

[0057] Although the disclosed embodiments are not limited in this respect, the first group of disclosed polishing compositions can be particularly well suited for CMP applications in which a high silicon oxide removal rate is desirable. By way of example only, the first group of disclosed polishing compositions can be advantageously utilized in bulk oxide CMP applications in which a high silicon oxide removal rate is important and silicon oxide removal rate selectivity (e.g., versus silicon nitride and / or polysilicon) is less important (or not at all important).

[0058] In the second group of disclosed polishing compositions, the cationic polymer can be characterized as having a low charge density. For example, the second group of disclosed compositions can include a cationic polymer having a charge density of less than about 6 meq / g (e.g., less than about 5 meq / g, less than about 4 meq / g, or less than about 3 meq / g).

[0059] Exemplary low charge density cationic polymers include polyquaternium-69, vinylcaprolactam / vp / dimethylaminoethyl methacrylate copolymer, polyquaternium-46, poly(diallyldimethylammonium-co-N-vinylpyrrolidone), polyquaternium-28, polyquaternium-44, polyquaternium-11, polyquaternium-68, polyquaternium-39, acrylamidopropyltrimonium chloride / acrylamide copolymer, polyquaternium-16, polyquaternium-7, succinylated epsilon polylysine, and poly(methacryloyloxyethyltrimethylammonium) (polyMADQUAT). In certain embodiments, the low charge density cationic polymer may comprise polyquaternium-7, succinylated epsilon polylysine, polyMADQUAT, or a mixture thereof. The charge density (meq / g) of each of the cationic polymers listed above is listed in Example 7.

[0060] Polishing compositions containing low charge density cationic polymers generally contain a relatively higher concentration of low charge density cationic polymer at the time of use. For example, the polishing composition may contain more than about 10 ppm by weight (e.g., more than about 15 ppm by weight, more than about 20 ppm by weight, more than about 25 ppm by weight, or more than about 30 ppm by weight) of low charge density cationic polymer at the time of use. Such polishing compositions may contain less than about 500 ppm by weight (e.g., less than about 400 ppm by weight, less than about 300 ppm by weight, less than about 250 ppm by weight, or less than about 200 ppm by weight) of low charge density cationic polymer at the time of use. It will be understood that the low charge density cationic polymer may be present in the polishing composition at a concentration bounded by any two of the above endpoints. For example, the polishing composition may contain from about 10 ppm to about 500 ppm by weight (e.g., from about 10 ppm to about 300 ppm by weight, from about 15 ppm to about 300 ppm by weight, or from about 20 ppm to about 200 ppm by weight) of the low charge density cationic polymer at the time of use.

[0061] It will be appreciated that the preferred concentration of low charge density cationic polymers tends to be inversely proportional to the charge density of the polymer. For compositions employing cationic polymer(s) having a charge density within the range of about 3 meq / g to about 6 meq / g, preferred concentrations may be within the range of about 10 ppm to about 100 ppm by weight (e.g., about 20 ppm to about 80 ppm by weight) at the point of use. For compositions employing cationic polymer(s) having a charge density less than about 3 meq / g, preferred concentrations may be significantly higher, e.g., within the range of about 30 ppm to about 500 ppm by weight (e.g., about 50 ppm to about 300 ppm by weight) at the point of use.

[0062] The polishing composition containing the low-density cationic polymer may further contain a silicon oxide polishing rate enhancer (i.e., a compound that increases the removal rate of silicon oxide (e.g., TEOS or HDP)). Suitable polishing rate enhancers may include, for example, carboxylic acid compounds that activate the substrate. Exemplary rate enhancers include, for example, picolinic acid, nicotinic acid, quinaldic acid, isonicotinic acid, acetic acid, and 4-hydroxybenzoic acid. In certain advantageous embodiments (and certain exemplary embodiments disclosed below), the rate enhancer includes picolinic acid, acetic acid, or a mixture thereof.

[0063] The polishing composition containing the low charge density cationic polymer may further contain a silicon nitride removal rate inhibitor (e.g., a silicon nitride stopper) containing, for example, an unsaturated carboxylic acid, such as an unsaturated monoacid. Suitable unsaturated monoacids include, for example, acrylic acid, 2-butenoic acid (crotonic acid), 2-pentenoic acid, trans-2-hexenoic acid, trans-3-hexenoic acid, 2-hexynoic acid, 2,4-hexadienoic acid, potassium sorbate, trans-2-methyl-2-butenoic acid, 3,3-dimethylacrylic acid, or combinations thereof, including their stereoisomers. In the exemplary embodiment disclosed below, the silicon nitride removal rate inhibitor is crotonic acid.

[0064] The polishing composition containing the low charge density cationic polymer may further contain a nonionic additive, such as a nonionic polymer. The nonionic additive may be, for example, a dispersant, a rheological agent, a polishing rate accelerator, a polishing rate suppressor, or a selectivity enhancer (to improve the removal rate ratio of one material to another). Suitable nonionic compounds may include water-soluble nonionic polymers and non-polymeric nonionic compounds. Nonionic compounds may include water-soluble polyethers, polyether glycols, alcohol ethoxylates, polyoxyalkylene alkyl ethers, polyesters, vinyl acrylates, and combinations thereof.

[0065] The nonionic polymer may be a homopolymer or copolymer and may contain virtually any suitable nonionic monomer unit. Exemplary nonionic polymers include polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, poly(vinyl phenyl ketone), poly(vinyl pyridine), poly(acrylamide), polyacrolein, poly(methyl methacrylic acid), polyethylene, polyoxyethylene lauryl ether, polyhydroxyethyl methacrylate, poly(ethylene glycol) monolaurate, poly(ethylene glycol) monooleate, poly(ethylene glycol) distearate, and copolymers containing one or more of the above monomer units. Exemplary copolymers include poly(vinyl acetate-co-methyl methacrylate), poly(vinyl pyrrolidone-co-vinyl acetate), and poly(ethylene-co-vinyl acetate). Certain exemplary embodiments disclosed below include poly(vinyl pyrrolidone) nonionic polymer additives.

[0066] Although the disclosed embodiments are not limited in this respect, the second group of disclosed polishing compositions may be particularly well suited for CMP applications where a high silicon oxide removal rate is desirable, but good topography (e.g., low dishing and corrosion) and / or high selectivity to silicon nitride and / or polysilicon are also desired. In such applications, a high silicon oxide removal rate is preferably balanced with good topography performance and high selectivity.

[0067] It will be understood that the disclosed polishing compositions (e.g., those in the first group of polishing compositions and / or those in the second group of polishing compositions) may further contain virtually any other optional additives, including, for example, secondary polishing rate accelerators or inhibitors, dispersants, conditioners, scale inhibitors, chelating agents, stabilizers, pH buffers, and biocides. Such additives are purely optional. The disclosed embodiments are not so limited and do not require the use of any one or more of such additives.

[0068] For example, the disclosed polishing compositions may optionally contain a biocide. The biocide may include virtually any suitable biocide, such as an isothiazolinone biocide, such as methylisothiazolinone or benzisothiazolone. The amount of biocide in the polishing composition at the time of use is typically in the range of about 1 ppm to about 100 ppm by weight, e.g., about 5 ppm to about 75 ppm by weight, at the time of use.

[0069] The polishing composition may be prepared using any suitable technique, many of which are known to those skilled in the art. The polishing composition may be prepared in a batch or continuous process. Generally, the polishing composition may be prepared by combining its components in any order. The term "component" as used herein includes individual components (e.g., abrasive grains, cationic polymer, and any optional additives). For example, the cationic polymer may be added to an aqueous carrier (e.g., water) at a desired concentration. The pH may then be adjusted (if desired), and the cubic ceria abrasive may be added at a desired concentration to obtain the polishing composition. The polishing composition may be prepared prior to use by adding one or more components to the polishing composition immediately before use (e.g., within about 1 minute before use, or within about 1 hour before use, or within about 1 or about 7 days before use). The polishing composition may also be prepared by mixing the components on the surface of a substrate during a polishing operation (e.g., in a polishing pad).

[0070] In certain embodiments, the polishing composition can be provided as a "two-pack" system. For example, a first pack can contain cubic ceria abrasive particles and other optional components, and a second pack can contain a cationic polymer and other optional components. The first and second packs can be shipped separately and combined on the polishing pad prior to polishing (e.g., within one hour or one day of polishing) or during the CMP operation.

[0071] The polishing composition of the present invention may be provided at a concentration intended to be diluted with an appropriate amount of water before use. In such an embodiment, the polishing composition concentrate may contain cubic ceria abrasive particles and the other components described above in amounts such that, upon dilution of the concentrate with an appropriate amount of water, each component of the polishing composition is present in the polishing composition in an amount within the appropriate range listed above for each component. For example, the cubic ceria abrasive particles, the cationic polymer, and other optional additives may each be present in the polishing composition in an amount that is about 3 times (e.g., about 4 times, about 5 times, about 6 times, about 7 times, about 8 times, about 10 times, about 15 times, about 20 times, or about 25 times) greater than the point-of-use concentration listed above for each component, such that when the concentrate is diluted with an equal volume of water (e.g., 2 equal volumes of water, 3 equal volumes of water, 4 equal volumes of water, 5 equal volumes of water, 6 equal volumes of water, 7 equal volumes of water, 9 equal volumes of water, 14 equal volumes of water, 19 equal volumes of water, or 24 equal volumes of water), each component will be present in the polishing composition in an amount within the range listed above for each component.

[0072] In embodiments in which the polishing composition is provided as a two-pack system, either or both packs may be provided as concentrates and require dilution before mixing with the other pack. For example, in one embodiment, the first pack is provided as a concentrate containing cubic ceria abrasive particles at a concentration that is about three times (e.g., about five times, about eight times, about ten times, about fifteen times, or about twenty times) greater than the point-of-use concentrations listed above. The concentrated first pack may be mixed with a suitable amount of water before combining with the second pack. Similarly, the second pack may be provided as a concentrate having a cationic polymer concentration that is about three times (e.g., about five times, about eight times, about ten times, about fifteen times, or about twenty times) greater than the point-of-use concentrations listed above. In such embodiments, the concentrated second pack may be mixed with a suitable amount of water before combining with the first pack. In certain embodiments, both the first and second packs may be diluted with water before being combined. The disclosed embodiments are not limited in these respects.

[0073] The polishing method of the present invention is particularly suitable for use in conjunction with a chemical mechanical polishing (CMP) device, including, for example, a platen and a pad attached thereto.As known to those skilled in the art, polishing of a substrate is carried out when the substrate is placed in contact with a polishing pad and the polishing composition of the present invention, and then the polishing pad and the substrate are moved relative to each other to wear away at least a portion of the substrate.The method of the present invention includes applying the above-mentioned composition of the present invention, contacting a substrate (e.g., a wafer) with the composition of the present invention, moving the polishing composition relative to the substrate, and polishing the substrate by wearing away the substrate to remove a portion of the silicon oxide material from the substrate.

[0074] The substrate typically includes a silicon oxide dielectric layer, many of which are well known. For example, the silicon oxide layer may include, consist of, or consist essentially of any one or more of the following: tetraethoxysilane (TEOS), high density plasma (HDP) oxide, phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), high aspect ratio process (HARP) oxide, spin-on dielectric (SOD) oxide, chemical vapor deposition (CVD) oxide, plasma-enhanced tetraethylorthosilicate (PETEOS), thermal oxide, or undoped silicate glass.

[0075] The polishing composition desirably exhibits a high removal rate when polishing a substrate containing a silicon oxide material. For example, when polishing a silicon wafer containing high-density plasma (HDP) oxide and / or plasma-enhanced tetraethyl orthosilicate (PETEOS), spin-on glass (SOG), and / or tetraethyl orthosilicate (TEOS), the polishing composition desirably exhibits a silicon oxide removal rate of about 2000 Å (200 nm) / min or more (e.g., about 4000 Å (400 nm) / min or more, about 5000 Å (500 nm) / min or more, or about 6000 Å (600 nm) / min or more). In certain embodiments (e.g., when using the first group of polishing compositions), the polishing composition desirably exhibits a very high silicon oxide removal rate (e.g., 6,000 Å (600 nm) / min or greater, 7,000 Å (700 nm) / min or greater, 8,000 Å (800 nm) / min or greater, or even 9,000 Å (900 nm) / min or greater).

[0076] In certain embodiments (e.g., when using the second group of polishing compositions), the polishing composition can advantageously exhibit both a high silicon oxide removal rate and high selectivity to silicon nitride and / or polysilicon. In such embodiments, the silicon oxide removal rate can be 3000 Å (300 nm) / min or greater (e.g., about 4000 Å (400 nm) / min or greater, or about 5000 Å (500 nm) / min or greater), and the silicon oxide to silicon nitride and / or silicon oxide to polysilicon selectivity can be at least 20 to 1 (e.g., at least 40 to 1, at least 60 to 1, at least 80 to 1, or even at least 100 to 1).

[0077] The polishing compositions of the second group may further desirably exhibit low dishing and erosion when polishing a substrate having a patterned silicon oxide layer. For example, when polishing a patterned wafer including a silicon oxide material filled on a polysilicon trench, the polishing compositions desirably exhibit erosion and dishing of less than about 200 Å (20 nm) (e.g., less than about 150 Å (15 nm), less than about 100 Å (10 nm), less than about 75 Å (7.5 nm), or less than about 50 Å (5 nm)). Furthermore, the polishing compositions and methods desirably achieve such erosion and dishing levels over a wide range of line widths and pattern densities, for example, line widths in the range of 0.5 μm to 100 μm and pattern densities in the range of 10% to 90%.

[0078] It will be appreciated that the present disclosure includes many embodiments, including but not limited to the following.

[0079] In a first embodiment, the chemical-mechanical polishing composition includes a liquid carrier; cubic ceria abrasive particles dispersed in the liquid carrier; and a cationic polymer having a charge density greater than about 6 meq / g.

[0080] A second embodiment may include the first embodiment, in which the cubic ceria abrasive particles include a mixture of cerium oxide and lanthanum oxide.

[0081] A third embodiment may include any one of the first or second embodiments, wherein the cubic ceria abrasive particles have a molar ratio of lanthanum to lanthanum plus cerium in the range of about 1 to about 15 percent.

[0082] In the fourth embodiment, the cubic ceria abrasive particles are approximately 3 m 2 / g ~ approx. 14m 2 The present invention may include any one of the first to third embodiments having a BET surface area in the range of 0.1 to 0.25 μm / g.

[0083] A fifth embodiment may include any one of the first to fourth embodiments, wherein the cubic ceria abrasive particles have an average particle size in the range of about 50 nm to about 500 nm.

[0084] A sixth embodiment may include any one of the first through fifth embodiments, including from about 0.001 to about 1 weight percent cubic ceria abrasive particles at the point of use.

[0085] A seventh embodiment may include any one of the first through sixth embodiments, wherein the cationic polymer has a charge density greater than about 9 meq / g.

[0086] An eighth embodiment may include any one of the first to seventh embodiments, wherein the cationic polymer includes at least one of poly(vinylimidazole), poly(vinylimidazolium), poly(vinylmethylimidazolium), epichlorohydrin-dimethylamine, polydiallyldimethylammonium, poly(vinylmethylimidazolium) methylsulfate, polyethyleneimine, polylysine, polyhistidine, and polyarginine.

[0087] A ninth embodiment may include any one of the first to eighth embodiments, wherein the cationic polymer is poly(vinylimidazolium), polylysine, or a mixture thereof.

[0088] A tenth embodiment may include any one of the first to ninth embodiments, including about 0.1 ppm to about 20 ppm by weight of cationic polymer at the point of use.

[0089] An eleventh embodiment may include any one of the first to tenth embodiments, including about 1 ppm to about 10 ppm by weight of cationic polymer at the point of use.

[0090] The twelfth embodiment may include any one of the first to eleventh embodiments, further including a carboxylic acid-silicon oxide polishing rate enhancer.

[0091] A thirteenth embodiment may include the twelfth embodiment, wherein the carboxylic acid is picolinic acid, acetic acid, 4-hydroxybenzoic acid, or a mixture thereof.

[0092] A fourteenth embodiment may include any one of the first to thirteenth embodiments, which has a pH in the range of about 3 to about 5 at the time of use.

[0093] A fifteenth embodiment may include any one of the first through fourteenth embodiments, including from about 0.001 to about 1 weight percent cubic ceria abrasive particles at the time of use, and from about 0.1 ppm to about 20 ppm by weight of poly(vinylimidazolium), polylysine, or a mixture thereof at the time of use.

[0094] A sixteenth embodiment may include any one of the first to fifteenth embodiments, having a pH in the range of about 3 to 5 at the time of use, and further including picolinic acid, acetic acid, or a mixture thereof.

[0095] A seventeenth embodiment may include any one of the first through sixteenth embodiments, including from about 0.001 to about 1 weight percent cubic ceria abrasive particles at the point of use; the cubic ceria abrasive particles include a mixture of cerium oxide and lanthanum oxide and have an average particle size in the range of from about 50 to about 500 nm; and the cationic polymer includes poly(vinylimidazolium), polylysine, or a mixture thereof.

[0096] An eighteenth embodiment may include any one of the first to seventeenth embodiments, having a pH in the range of about 3 to 5 at the time of use, and further including picolinic acid, acetic acid, or a mixture thereof.

[0097] A nineteenth embodiment includes a method for chemical-mechanical polishing a substrate comprising a silicon oxide dielectric material, the method including: (a) applying a polishing composition comprising any one of the first through eighteenth embodiments; (b) contacting the substrate with the applied polishing composition; (c) moving the polishing composition relative to the substrate; and (d) polishing the substrate by abrading the substrate to remove a portion of the silicon oxide dielectric material from the substrate.

[0098] A twentieth embodiment may include the nineteenth embodiment, wherein the removal rate of silicon oxide dielectric material is greater than about 6,000 Å (600 nm) / minute in (d).

[0099] A twenty-first embodiment may include any one of the nineteenth to twentieth embodiments, in which the cationic polymer is polylysine or poly(vinylimidazolium).

[0100] A twenty-second embodiment may include any one of the nineteenth through twenty-first embodiments, in which the polishing composition, at the point of use, comprises from about 0.001 to about 1 weight percent cubic ceria abrasive particles, the cubic ceria abrasive particles comprising a mixture of cerium oxide and lanthanum oxide and having an average particle size in the range of from about 50 to about 500 nm.

[0101] A twenty-third embodiment may include any one of the nineteenth to twenty-second embodiments, in which the polishing composition further includes picolinic acid, acetic acid, or a mixture thereof.

[0102] A 24th embodiment may include any one of the 19th to 23rd embodiments, in which applying the polishing composition includes (ai) applying a polishing concentrate, and (aii) diluting the polishing concentrate with at least a portion of water to form a portion of the polishing concentrate.

[0103] A 25th embodiment may include any one of the 19th to 24th embodiments, in which applying the polishing composition includes (ai) applying a first pack containing cubic ceria abrasive particles and a second pack containing a cationic polymer, and (aii) combining the first and second packs to obtain the polishing composition.

[0104] A 26th embodiment may include any one of the 19th to 25th embodiments, wherein at least one of the first and second packs is diluted with water before combining in (aii).

[0105] The following examples further illustrate the invention but, of course, should not be construed as limiting its scope in any way. Various substrates were polished using an Applied Materials Mirra® polishing tool (available from Applied Materials, Inc.). Blanket wafers were polished for 60 seconds on the Mirra® at a platen speed of 100 rpm, a head speed of 85 rpm, a downforce of 3 psi (20684.28 Pa), and a slurry flow rate of 150 ml / min. The wafers were polished on a NexPlanar® E6088 pad (Cabot Microelectronics Corporation) with in-situ conditioning using a Saesol DS8051 conditioner at a downforce of 6 lbs (2.7126 kg).

[0106] Blanket tetraethyl orthosilicate (TEOS), high-density plasma (HDP) oxide, SiN-PE wafers, and polysilicon wafers were polished in the examples that follow. TEOS wafers were obtained from WRS Materials and contained a 20 kÅ (2000 nm) TEOS layer. HDP wafers were obtained from Silyb and contained a 10 kÅ (1000 nm) HDP oxide layer. SiN-PE wafers were obtained from Advantec and contained a 5 kÅ (500 nm) PE SiN layer. Polysilicon wafers were obtained from WRS Materials and contained a 10 kÅ (1000 nm) poly-Si layer. Patterned HDP wafers were obtained from Silyb and contained a 4 kÅ (400 nm) HDP oxide layer of STI1 with a 2 kÅ (200 nm) underlying polysilicon. [Example]

[0107] Example 1 A raw cerium oxide dispersion was prepared as follows: A cerium nitrate solution was prepared by combining 13.1 kg of a 3 M cerium(III) nitrate solution, 0.3 kg of a 3 M lanthanum nitrate solution, 2.0 kg of a 68% nitric acid (HNO) solution, 0.5 kg of deionized water, and cerium(IV) nitrate in a molar ratio of cerium(IV) to cerium (total) equal to 0.000055. The cerium nitrate solution was then degassed in a 20 L vessel under stirring and nitrogen bubbling.

[0108] An aqueous ammonia solution was prepared by combining 75 kg of deionized water and 13.1 kg of 25% aqueous ammonia solution (such that the molar ratio of NH4OH in the aqueous ammonia solution to the sum of cerium and lanthanum in the cerium nitrate solution was 9.0), and then degassed in a 100 L jacketed reactor under stirring and nitrogen bubbling.

[0109] The cerium nitrate solution was then added to the aqueous ammonia solution at ambient temperature under nitrogen purge and with the same stirring. The temperature of the reaction mixture was then increased to 80°C (353K) and maintained at that temperature for 18 hours. The reaction mixture was then allowed to cool and, under cooling, acidified to pH 2 by adding 68% nitric acid.

[0110] The reaction mixture was then filtered and washed with deionized water. When the conductivity of the washed solution was less than 0.04 mS / cm, the washing was repeated. Deionized water was added to adjust the final cerium oxide concentration to 10 weight percent. The cubic ceria abrasive particles contained 2.5 mole percent lanthanum oxide and 97.5 mole percent cerium oxide.

[0111] The BET specific surface area was determined by nitrogen adsorption to be 11.8 m per gram. 2 The average particle size was 102 nm as measured by a Horiba 960 and 140 nm as measured by a Malvern Zetasizer.

[0112] Example 2 Six polishing compositions were tested to evaluate the effect of poly(vinylimidazolium) methyl sulfate (PVI) and acetic acid on TEOS removal rates. The compositions contained different levels of PVI as follows: no PVI (2A), 1 ppm by weight (2B, 2E, and 2F), 2 ppm by weight (2C), and 4 ppm by weight (2D). Compositions 2E and 2F further contained 50 ppm by weight of acetic acid (2E) and 500 ppm by weight of acetic acid (2F). Each composition further contained 500 ppm by weight of picolinic acid and was prepared using the raw ceria dispersion described above in Example 1. The polishing compositions were prepared by first adding appropriate amounts of picolinic acid, acetic acid, and PVI to deionized water. An appropriate amount of the raw ceria dispersion from Example 1 was then added so that each composition contained 0.2 weight percent cubic ceria abrasive particles. The pH of each composition was approximately 4.

[0113] A blanket TEOS wafer was polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing results are shown in Table 2. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). Table 2 [Table 2]

[0114] From the results reported in Table 2, it is readily apparent that the TEOS removal rate increases with increasing PVI concentration (compared to compositions 2A, 2B, 2C, and 2D). This is contrary to what is generally observed for conventional wet ceria. It is further apparent that the removal rate is not strongly affected by acetic acid, especially at lower concentrations, e.g., 50 ppm by weight (compared to compositions 2A, 2E, and 2F).

[0115] Example 3 Three polishing compositions were tested to evaluate the effect of cationic polyvinyl alcohol (cat PVOH) on TEOS removal rate. Composition 3A was identical to Composition 2A. The compositions contained different levels of cat PVOH as follows: no cat PVOH (3A), 1 ppm by weight (3B), and 5 ppm by weight (3C). Each composition further contained 500 ppm by weight of picolinic acid and was prepared using the raw ceria dispersion described above in Example 1. The polishing compositions were prepared by first adding appropriate amounts of picolinic acid and GOHSENX K-434 (a cationic PVOH available from Mitsubishi Chemical) to deionized water. An appropriate amount of the raw ceria dispersion from Example 1 was then added so that each composition contained 0.2 weight percent cerium oxide. The pH of each composition was approximately 4.

[0116] A blanket TEOS wafer was polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing results are shown in Table 3. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). Table 3 [Table 3]

[0117] As is readily apparent from the results reported in Table 3, at low levels (1 ppm), cat PVOH has little or no effect on the TEOS removal rate. At higher levels (5 ppm), cat PVOH provides a modest increase in the TEOS removal rate.

[0118] Example 4 Two polishing compositions were tested. Composition 4A was identical to Composition 2A. Composition 4B contained 0.017 weight percent maltol, 0.25 weight percent Emulgen A-500 (polyoxyethylene distyrenated phenyl ether available from KAO Global Chemicals), 0.75 weight ppm PAS-J-81 (a polyDADMAC acrylamide copolymer trademarked by Nitto Boseki Co.), and 0.023 weight percent propanoic acid. Each composition was prepared using the raw ceria dispersion described above in Example 1 and contained 0.2 weight percent cerium oxide. The pH of each composition was approximately 4.0.

[0119] Blanket TEOS and polysilicon wafers were polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing results are shown in Table 4. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). Table 4 [Table 4]

[0120] As is readily apparent from the results set forth in Table 4, composition 4B, which includes a cationic polymer, exhibited similar TEOS removal rates and significantly better selectivity to polysilicon.

[0121] Example 5 Twelve polishing compositions were tested to evaluate the effect of cationic polymer loading on TEOS removal rate. Compositions 5A-5L were prepared by combining a first pack (A pack) with deionized water and the corresponding second pack (B pack). The A pack contained 1000 ppm by weight picolinic acid, 300 ppm by weight Kordex MLX biocide available from DuPont, and 2 weight percent ceria abrasive particles. In Compositions 5A-5D, wet-process ceria (HC60™ available from Rhodia) was used as the first control ceria and combined with deionized water, picolinic acid, and Kordex MLX. In Compositions 5E-5H, sintered ceria (the ceria abrasive used in Polishing Composition 1C of commonly assigned U.S. Patent No. 9,505,952) was used as the second control ceria and combined with deionized water, picolinic acid, and Kordex MLX. For compositions 51-5L, the raw ceria dispersion described in Example 1 was combined with deionized water, picolinic acid, and Kordex MLX. The pH value of each A pack was approximately 4.

[0122] The B pack contained 500 ppm by weight of polyvinylpyrrolidone (PVP) (having a molecular weight of 5000 g / mol), 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 150 ppm by weight of Kordek MLX biocide, and a cationic polymer. In compositions 5A, 5E, and 5I, the cationic polymer contained 100 ppm by weight of polyquaternium-7. In compositions 5B, 5F, and 5J, the cationic polymer contained 200 ppm by weight of polyquaternium-7. In compositions 5C, 5G, and 5K, the cationic polymer contained 100 ppm by weight of polyMADQUAT. In compositions 5D, 5H, and 5L, the cationic polymer contained 200 ppm by weight of polyMADQUAT. The pH of the B pack was approximately 4.

[0123] A portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts of the B pack to obtain ready-to-use compositions containing 0.2 weight percent ceria abrasive and either 30 weight percent or 60 weight percent cationic polymer. The pH at the time of use was about 4 for each composition.

[0124] A blanket TEOS wafer was polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing results are shown in Table 5. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). Table 5 [Table 5]

[0125] As is readily apparent from the results reported in Table 5, Compositions 5H-5L containing cubic ceria abrasive particles exhibited superior removal rates compared to the control ceria composition. Also, Compositions 5I and 5K containing 60 ppm by weight of cationic polymer and cubic ceria abrasive particles exhibited high removal rates. Similar control ceria compositions 5B, 5D, 5F, and 5H did not exhibit significant removal rates at 60 ppm by weight of cationic polymer.

[0126] Example 6 Four polishing compositions were tested to evaluate the effect of cationic polymer loading on TEOS removal rate and dishing. Compositions 6A-6D were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. The A pack contained 1000 ppm by weight picolinic acid, 300 ppm by weight Kordek MLX biocide available from DuPont, and 2 weight percent ceria abrasive particles. For Composition 6A, the A pack contained the first control ceria described above for Compositions 5A-5D. For Compositions 6B-6D, the ceria abrasive particles in the A pack were obtained by combining 1 part raw ceria dispersion described in Example 1 with 4 parts deionized water. The pH of the A packs was approximately 4.

[0127] The B pack contained PVP (5000 g / mol) (333 ppm by weight for Compositions 6A, 6B, and 6C, and 500 ppm by weight for Composition 6D), 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 150 ppm by weight of Kordek MLX biocide, and Polyquaternium-7 (125 ppm by weight for Composition 6A, 140 ppm by weight for Composition 6B, and 200 ppm by weight for Compositions 6C and 6D). The pH of the B pack was about 4.

[0128] A portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts B pack to obtain ready-to-use compositions containing 0.2 weight percent ceria abrasive and 37.5 ppm (6A), 42 ppm (6B), or 60 ppm (6C and 6D) polyquaternium-7 by weight.

[0129] Blanket TEOS wafers were polished for 60 seconds, and patterned HDP wafers were polished to 100% overpolish in the mirra® under the conditions listed above. The polishing results are shown in Table 6. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Dishing is in units of angstroms (Å (0.1 nm)). Table 6 [Table 6]

[0130] As is readily apparent from the results set forth in Table 6, compositions 6B-6D exhibit significantly improved (greater than 2x improvement) TEOS removal rates compared to the control composition 6A, and compositions 6C and 6D (especially 6D) exhibit excellent removal rate to dishing ratios.

[0131] Example 7 Forty-five polishing compositions were tested to evaluate the effect of charge density on TEOS removal rate. Each composition was prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. The A pack contained 20 weight percent of the starting ceria dispersion prepared in Example 1, 1750 weight ppm picolinic acid, and 75 weight ppm Kordek MLX biocide. The remainder was deionized water.

[0132] The B pack contained 333 ppm by weight of PVP (5000 g / mol), 2250 ppm by weight of acetic acid, 1707 ppm by weight of crotonic acid, 500 ppm by weight of Kordek MLX, and 100 ppm, 300 ppm, or 500 ppm by weight of cationic polymer. The cationic polymers were Aquastyle 300AF (Polyquaternium-69 available from Ashland Chemical) (7A), Advantage S (vinylcaprolactam / VP / dimethylaminoethyl methacrylate copolymer available from Ashland Chemical) (7B), Luviquat Hold (Polyquaternium-46 available from BASF) (7C), poly(diallyldimethylammonium) chloride-co-N-vinylpyrrolidone with a DADMAC:NVP ratio of 9:91 (referred to as DADNPV-9:91) (7D), Gafquat HS-100 (Polyquaternium-28 available from Ashland Chemical) (7E), Luviquat Ultra (Polyquaternium-44 available from BASF) (7F), Luviquat PQ 11 (Polyquaternium-11 available from BASF) (7G), and Luviquat Supreme (Polyquaternium-68 available from BASF) (7H), Merquat 3940 (Polyquaternium-39 available from Lubrizol) (7I), N-Hance SP 100 (Acrylamidopropyltrimonium chloride / acrylamide copolymer available from Ashland Chemical) (7J), Luviquat FC The compositions included 370 (Polyquaternium-16 available from BASF) (7K), poly(diallyldimethylammonium) chloride-co-N-vinylpyrrolidone with a DADMAC:NVP ratio of 28:72 (referred to as DADNPV-28:72) (7L), polyquaternium-7 (7M), poly(diallyldimethylammonium) chloride-co-N-vinylpyrrolidone with a DADMAC:NVP ratio of 70:30 (referred to as DADNPV-70:30) (7N), or polyMADQUAT (7O).

[0133] The charge density of the listed cationic polymers with known structures was calculated as described above with respect to Equations 1 and 2. The relative charge density (relative to Polyquaternium-7) of each listed cationic polymer was determined via PVSK titration as described above and in more detail below. The charge density of the listed cationic polymers with unknown structures was calculated as the product of the relative charge density and the calculated charge density of Polyquaternium-7. These charge density (CD) values ​​are listed in Table 7A.

[0134] The PVSK titration procedure used to determine the relative charge density values ​​listed in Table 7A is as follows: An aqueous solution of each cationic polymer was prepared by mixing the cationic polymer in deionized water. The concentration of each cationic polymer was 68 ppm cationic polymer. A diluted PVSK solution was prepared by diluting 1 part by weight of potassium polyvinyl sulfate N / 400 (available from Wako Chemicals) with 1.5 parts by weight of deionized water (2.5X dilution). A diluted toluidine blue-O solution was prepared by diluting 0.1 grams of toluidine blue-O (available from Sigma-Aldrich) with 99.9 grams of deionized water to obtain 100 grams of diluted toluidine blue-O solution (0.1 percent toluidine blue-O).

[0135] A blue cationic polymer solution was obtained by adding 105 μL (approximately 2 drops) of diluted toluidine blue-O solution to 25 grams of aqueous cationic polymer solution (68 ppm cationic polymer). The diluted PVSK solution was titrated into the blue cationic polymer solution to the end point (i.e., until the color of the blue cationic polymer solution changed from blue to pink). The volume of the diluted PVSK solution titrated was recorded. Each of the listed cationic polymers was tested three times. The average volume of the diluted PVSK solution titrated was used to calculate the relative charge density.

[0136] As above, polyquaternium-7 cationic polymer was used as the standard. Relative charge densities were calculated as described above for Equation 3, which involves dividing the average volume of titrant used for each cationic polymer by the average volume of titrant used for polyquaternium-7. Measured charge densities were calculated as described above for Equation 4 by multiplying the relative charge density by the calculated charge density for polyquaternium-7 (obtained from Equation 1, the structure of polyquaternium-7 being known). Table 7A [Table 7]

[0137] Prior to polishing, a portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts of each B pack to obtain ready-to-use Compositions 7A-7O containing 0.2 weight percent ceria abrasive and 30, 90, or 150 weight ppm of the listed cationic polymer.

[0138] A blanket TEOS wafer was polished for 30 seconds in a Logitech polishing tool using the conditions listed above for the Mirra® tool. The polishing results are shown in Table 7B. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Table 7B [Table 8]

[0139] As is evident from the results shown in Table 7B, the TEOS removal rate can be affected by both the cationic polymer loading and the charge density of the cationic polymer. At higher charge densities, the TEOS removal rate tends to decrease at higher cationic polymer loading levels. At lower charge densities, the TEOS removal rate is less dependent on the cationic polymer loading level (at least within the range of 30 ppm by weight to 150 ppm by weight).

[0140] Example 8 Four polishing compositions were tested to evaluate the effect of cationic polymer loading on TEOS removal rate and dishing. Compositions 8A-8D were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. For Compositions 8A and 8D, the A pack contained 1750 ppm by weight of picolinic acid, 75 ppm by weight of Kordek MLX, and 2 percent by weight of ceria abrasive particles. Composition 8A contained the first control ceria described above in Example 5. Composition 8D contained the raw ceria dispersion described above in Example 1. For Compositions 8B and 8C, the A pack contained 3500 ppm by weight of picolinic acid, 75 ppm by weight of Kordek MLX, and 2 percent by weight of the second control ceria described above in Example 5.

[0141] The B pack for compositions 8A-8D contained the following components: (8A) 333 ppm by weight of PVP (2500 g / mol), 2250 ppm by weight of acetic acid, 417 ppm by weight of crotonic acid, 125 ppm by weight of polyquaternium-7, and 150 ppm by weight of Kordek MLX. (8B) 667 ppm by weight polyethylene glycol octadecyl ether (Brij® S20), 1500 ppm by weight acetic acid, 117 ppm by weight polyquaternium-7, and 150 ppm by weight Kordek MLX. (8C) 667 ppm by weight Brij® S20, 1500 ppm by weight acetic acid, 833 ppm by weight crotonic acid, 133 ppm by weight polyquaternium-7, and 150 ppm by weight Kordek MLX. (8D) 333 ppm by weight PVP (2500 g / mol), 2250 ppm by weight acetic acid, 3413 ppm by weight crotonic acid, 200 ppm by weight polyquaternium-7, and 150 ppm by weight Kordek MLX.

[0142] A portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts B pack to obtain ready-to-use compositions containing 0.2 weight percent ceria abrasive, 37.5 weight ppm (8A), 35 weight ppm (8B), or 40 weight ppm (8C), and 60 weight ppm polyquaternium-7, and 125 weight ppm (8A), 0 weight ppm (8B), 250 weight ppm (8C), and 1000 weight ppm (8D) crotonic acid.

[0143] Blanket TEOS wafers were polished for 60 seconds, and patterned HDP wafers were polished to 100% overpolish in the mirra® under the conditions listed above. The polishing results are shown in Table 8. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Dishing is in units of angstroms (Å (0.1 nm)). Table 8 [Table 9]

[0144] As is readily apparent from the results set forth in Table 8, Composition 8D, which includes cubic ceria abrasive particles, achieves both a higher TEOS removal rate and an improved removal rate-to-dishing ratio. The cubic ceria abrasive particles achieve even higher TEOS removal rates at higher cationic polymer concentrations, thereby allowing the use of higher cationic polymers to reduce dishing (and eliminate the removal rate-to-dishing ratio).

[0145] Example 9 Three polishing compositions were tested in Applied Materials Reflexion® polishing tools. Compositions 9A-9C were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. In each of the compositions, the A pack contained 1750 ppm by weight picolinic acid, 75 ppm by weight Kordek MLX, and 2 weight percent ceria obtained from the raw ceria dispersion described above in Example 1.

[0146] The B pack for compositions 9A-9C contained the following components: (9A) 500 ppm by weight of PVP (9700 g / mol), 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 500 ppm by weight of Luviquat polyquaternium 11 (see Example 7), and 150 ppm by weight of Kordek MLX. (9B) 500 ppm by weight of PVP (9700 g / mol), 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 150 ppm by weight of polyquaternium-7, and 150 ppm by weight of Kordek MLX. (9C) 500 ppm by weight of PVP (9700 g / mol), 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 100 ppm by weight of polyDADMAC, and 150 ppm by weight of Kordek MLX.

[0147] A portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts of the B pack to obtain ready-to-use compositions containing 0.2 weight percent ceria abrasive and 150 ppm (9A), 40 ppm (9B), or 30 ppm (8C) cationic polymer by weight.

[0148] Blanket TEOS wafers were polished for 60 seconds, and patterned HDP wafers were polished to 100% overpolish using an Applied Materials Reflexion® tool and a NexPlanar® E6088 polishing pad at a platen speed of 93 rpm, a head speed of 87 rpm, a downforce of 2 psi (13789.52 Pa), and a slurry flow rate of 175 ml / min, while in situ conditioning was performed using a Saesol DS8051 conditioner with a downforce of 6 lbs (2.7126 kg). The polishing results are shown in Table 9. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Dishing is in units of angstroms (Å (0.1 nm)). Table 9 [Table 10]

[0149] As is readily apparent from the results set forth in Table 9, composition 8A, which included Luviquat PQ11 cationic polymer, achieved a high TEOS removal rate, composition 8B, which included polyquaternium-7 cationic polymer, achieved both a high TEOS removal rate and very low dishing, and composition 9C, which included polyDADMAC cationic polymer, had a very low TEOS removal rate.

[0150] Example 10 Ten polishing compositions were tested to evaluate the effect of crotonic acid on TEOS removal rate. Compositions 10A-10J were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. For Compositions 10A-10F, the A pack contained 1750 ppm by weight picolinic acid, 75 ppm by weight Kordex MLX, and 2 percent by weight ceria. Compositions 10A-10D contained the first control ceria described above in Example 5, while Compositions 10E and 10F used the starting ceria dispersion described above in Example 1. For Compositions 10G-10J, the A pack contained 3500 ppm by weight picolinic acid, 75 ppm by weight Kordex MLX, and 2 percent by weight of the second control ceria described above in Example 5.

[0151] The B packs for Compositions 10A-10D and 10G-10J contained 667 ppm by weight of Brij® S20 (Example 8), 1500 ppm by weight of acetic acid, and 500 ppm by weight of Kordex MLX. The B packs of Compositions 10A-10D further contained 100 ppm by weight (10A and 10B) or 150 ppm by weight (10C and 10D) of Polyquaternium-7. The B packs of Compositions 10B and 10D still further contained 833 ppm by weight of crotonic acid.

[0152] The B packs of Compositions 10G-10J further contained 100 ppm by weight of polyMADQUAT. The B packs of Compositions 10H-10J still further contained 427 ppm by weight (10H), 1493 ppm by weight (10I), and 5000 ppm by weight (10J) crotonic acid.

[0153] The B packs for Compositions 10E and 10F contained 333 ppm by weight of PVP (2500 g / mol), 2167 ppm by weight of acetic acid, 200 ppm by weight of Polyquaternium-7, and 500 ppm by weight of Kordex MLX. The B packs for Compositions 10E and 10F further contained 1389 ppm by weight (10E) and 5689 ppm by weight (10F) crotonic acid.

[0154] A portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts B pack to obtain a ready-to-use composition containing 0.2 weight percent ceria abrasive. Blanket TEOS wafers were polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing results are shown in Table 10. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Concentrations of cationic polymer and crotonic acid are listed in ppm by weight. Table 10 [Table 11]

[0155] As is readily apparent from the results reported in Table 10, the TEOS removal rate increases with crotonic acid concentration for compositions containing cubic ceria abrasive particles (10E and 10F). The TEOS removal rate is essentially independent of crotonic acid concentration (low concentrations) for compositions containing the first control ceria (10A-10D). The TEOS removal rate decreases with crotonic acid concentration for compositions containing the second control ceria (10A-10D).

[0156] Example 11 Three polishing compositions were tested to evaluate the effect of PVP molecular weight on TEOS removal rate and dishing. Compositions 11A-11C were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. The A pack contained 1000 ppm by weight picolinic acid, 75 ppm by weight Kordex MLX, and 2 weight percent ceria, and was prepared using the raw ceria solution described above in Example 1.

[0157] Pack B contained 500 ppm by weight of PVP, 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 150 ppm by weight of Polyquaternium-7, and 150 ppm by weight of Kordex MLX. The PVP molecular weights were approximately 5000 g / mol (11A), 9700 g / mol (11B), and 66,800 g / mol (11C).

[0158] A portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts of the B pack to provide a ready-to-use composition containing 0.2 weight percent ceria abrasive.

[0159] A blanket TEOS wafer was polished for 60 seconds in a Mirra® tool under the conditions listed above. A patterned wafer was polished to 100% overpolish in a Reflexion® tool and a NexPlanar® E6088 polishing pad under the conditions listed above in Example 9. The polishing data is shown in Table 11. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Dishing is listed in angstroms (Å (0.1 nm)). Table 11 [Table 12]

[0160] As is readily apparent from the results set forth in Table 11, the highest removal rate and lowest dishing is achieved with composition 11A, which has a PVP molecular weight of about 5000 g / mol.

[0161] Example 12 Six polishing compositions were tested to evaluate the effect of epsilon polylysine (ePLL) on TEOS removal rate. Compositions 12A-12F were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. The A pack contained 1000 ppm by weight picolinic acid, 300 ppm by weight Kordex MLX, and 2 weight percent ceria. For Compositions 12A and 12B, the A pack contained the first control ceria described above in Example 5. For Compositions 12C and 12D, the A pack contained the second control ceria described above in Example 5. For Compositions 12E and 12F, the A pack contained an appropriate amount of the starting ceria dispersion described above in Example 1.

[0162] Pack B contained 500 ppm by weight of PVP (5000 g / mol), 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 150 ppm by weight of Kordex MLX, and 0 ppm by weight (12A, 12C, and 12E) or 33.3 ppm by weight (12B, 12D, and 12F) of ePLL (hydrochloride salt, free base).

[0163] A portion of the A pack was first combined with 6 parts deionized water and then further combined with 3 parts B pack to obtain a ready-to-use composition containing 0.2 weight percent ceria abrasive. Blanket TEOS wafers were polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing data are shown in Table 12. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Table 12 [Table 13]

[0164] As is readily apparent from the results reported in Table 12, the TEOS removal rate increased at low ePLL levels for compositions containing cubic ceria abrasive particles (12E and 12F). In contrast, the TEOS removal rate decreased at low ePLL levels for compositions containing control ceria (12A-12D).

[0165] Example 13 Seven polishing compositions were tested to evaluate the effect of epsilon polylysine (ePLL) on TEOS removal rate. Composition 13A was prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. The A pack contained 1000 ppm by weight picolinic acid, 300 ppm by weight Kordex MLX, and 2 weight percent ceria obtained from the raw ceria dispersion described above in Example 1. The B pack contained 500 ppm by weight PVP (5000 g / mol), 2250 ppm by weight acetic acid, 3413 ppm by weight crotonic acid, 200 ppm by weight polyquaternium-7, and 150 ppm by weight Kordex MLX. The A and B packs were combined as described above in Example 5.

[0166] Compositions 13B-13G were prepared in a single pack and contained 0.2 weight percent ceria abrasive particles obtained from the raw ceria dispersion described above in Example 1. Compositions 13B-13E further contained 500 ppm by weight of picolinic acid and 0 ppm (13B), 1 ppm (13C), 2 ppm (13D), or 4 ppm (13E) of poly(vinylimidazolium) methyl sulfate (PVI). Compositions 13F and 13G contained 100 ppm by weight of picolinic acid and 5 ppm (13F) or 10 ppm by weight of ePLL.

[0167] A blanket TEOS wafer was polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing data is shown in Table 13. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Table 13 [Table 14]

[0168] As is readily apparent from the results set forth in Table 13, the TEOS removal rate increased at low PVI and ePLL levels (1-5 ppm).

[0169] Example 14 Three polishing compositions were tested to evaluate the effect of epsilon polylysine (ePLL) on TEOS, high-density plasma (HDP) oxide, and SiN-PE removal rates. Compositions 14A-14C were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. The A pack for each composition contained 1000 ppm by weight picolinic acid, 300 ppm by weight Kordex MLX, and 2 weight percent ceria obtained from the raw ceria dispersion described above in Example 1.

[0170] The B pack for Composition 14A was identical to the B pack for Composition 13A described in Example 13. The B packs for Compositions 14B and 14C contained 500 ppm by weight of PVP (5000 g / mol), 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, 33 ppm by weight of ePLL (14B) or 100 ppm by weight of ePLL (14C), and 150 ppm by weight of Kordek MLX. The A and B packs were combined as described above in Example 5, such that Composition 14B contained 10 ppm by weight of ePLL per point of use and Composition 14C contained 30 ppm by weight of ePLL per point of use.

[0171] Blanket TEOS wafers, HDP oxide, and SiN-PE wafers were polished for 60 seconds in the Mirra® under the conditions listed above. The polishing data is shown in Table 14. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Table 14 [Table 15]

[0172] As is readily apparent from the results set forth in Table 14, composition 14B achieves superior TEOS and HDP removal rates.

[0173] Example 15 Five polishing compositions were tested to evaluate the effect of epsilon polylysine (ePLL) on TEOS removal rate in Applied Materials Reflexion® polishing tools. Compositions 15A-15E were prepared using the stock ceria dispersion described above with respect to Example 1, and contained 0.286 weight percent ceria abrasive particles. Compositions 15B, 15D, and 15E further contained 143 weight ppm picolinic acid. Compositions 15C, 15D, and 15E further contained 5 weight ppm (15C and 15D) or 10 weight ppm (15E) ePLL.

[0174] A blanket TEOS wafer was polished for 60 seconds in a Reflexion tool using a NexPlanar® E6088 polishing pad at a down force of 3 psi (20684.28 Pa), a platen speed of 93 rpm, a head speed of 87 rpm, and a slurry flow rate of 250 ml / min. The pad was conditioned in situ using a Saesol DS8051 conditioner. The polishing data is shown in Table 15. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Table 15 [Table 16]

[0175] As is readily apparent from the results set forth in Table 15, very high removal rates (approaching 10,000 Å (1,000 nm) / min) can be achieved in compositions containing cubic ceria abrasive, picolinic acid, and ePLL.

[0176] Example 16 Three polishing compositions were tested to evaluate the effect of lanthanum doping level in cubic ceria abrasive particles on TEOS removal rate. Composition 16A contained 0.28 weight percent of the first control ceria described above in Example 5. Composition 16B contained 0.28 weight percent of cubic ceria abrasive particles containing 2.5 mole percent lanthanum oxide and was prepared by diluting the raw ceria dispersion described above in Example 1 with 34 parts water to 1 part raw ceria dispersion. Composition 16C contained 0.28 weight percent of cubic ceria abrasive particles containing 10 mole percent lanthanum oxide and was prepared by diluting the ceria dispersion described in the following paragraph with 34 parts water to 1 part ceria dispersion. Compositions 16A-16C each had a pH of 4.

[0177] A cerium oxide dispersion was prepared as follows: A cerium nitrate solution was prepared by combining 11.5 kg of a 3 M cerium(III) nitrate solution, 1.3 kg of a 3 M lanthanum nitrate solution, 1.86 kg of a 68% nitric acid (HNO) solution, 0.5 kg of deionized water, and cerium(IV) nitrate in a molar ratio of cerium(IV) to cerium (total) equal to 0.0000125 (1 / 80,235). The cerium nitrate solution was then degassed in a 20 L vessel under stirring and nitrogen bubbling.

[0178] An aqueous ammonia solution was prepared by combining 70 kg of deionized water and 14 kg of a 25% aqueous ammonia solution (such that the molar ratio of NHOH in the aqueous ammonia solution to the sum of cerium and lanthanum in the cerium nitrate solution was 10. The aqueous ammonia solution was then degassed in a 100 L jacketed reactor under stirring and nitrogen bubbling.

[0179] The cerium nitrate solution was then added to the aqueous ammonia solution at ambient temperature with the same stirring under a nitrogen purge. The temperature of the reaction mixture was then increased to 88°C and held at that temperature for 13.5 hours. The reaction mixture was then allowed to cool and, under cooling, acidified to pH 2 by adding 68% nitric acid.

[0180] The reaction mixture was then filtered and washed with deionized water. When the conductivity of the washing solution was less than 0.04 mS / cm, the washing was repeated. Deionized water was added to adjust the final cubic ceria abrasive concentration to 10 weight percent. The cubic ceria abrasive particles contained 10 mole percent lanthanum oxide and 90 mole percent cerium oxide.

[0181] The BET specific surface area was determined by nitrogen adsorption to be 8.6 m per gram. 2 The average particle size measured by Malvern Zetasizer was 142 nm.

[0182] Blanket TEOS wafers were polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing results are shown in Table 16. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). Table 16 [Table 17]

[0183] As is readily apparent from the data set forth in Table 16, compositions 16B and 16C exhibited essentially equivalent TEOS removal rates that were greater than 1.6x the removal rate of control composition 16A.

[0184] Example 17 Two polishing compositions were tested to evaluate the effect of lanthanum doping level in cubic ceria abrasive particles on TEOS removal rate. Compositions 17A and 17B were prepared by combining the A pack with deionized water and the corresponding B pack. The A pack contained 1000 ppm by weight of picolinic acid, 300 ppm by weight of Kordek MLX biocide available from DuPont, and 2 weight percent of cubic abrasive particles. Composition 17A was prepared using the raw ceria dispersion described above in Example 1, which contained cubic ceria abrasive particles with 2.5 percent lanthanum oxide. Composition 17B was prepared using the ceria dispersion described above in Example 16, which contained cubic ceria abrasive particles with 10 percent lanthanum oxide. The B packs each contained 500 ppm by weight of PVP (5000 g / mol), 200 ppm by weight of polyquaternium-7, 2250 ppm by weight of acetic acid, 3413 ppm by weight of crotonic acid, and 150 ppm by weight of Kordek MLX biocide. The pH of both the A and B packs was 4.

[0185] Blanket TEOS wafers were polished for 60 seconds in a Mirra® tool under the conditions listed above. The polishing results are shown in Table 17. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). Table 17 [Table 18]

[0186] It is readily apparent from the results set forth in Table 17 that Composition 17A had a significantly higher TEOS removal rate than Composition 17B.

[0187] Example 18 A polishing composition concentrate was prepared to evaluate the effect of dilution with deionized water on the polishing performance of blanket and patterned wafers. The polishing composition concentrate contained 300 ppm by weight of PVP (5,000 g / mol), 100 ppm by weight of polyquaternium-7, 675 ppm by weight of acetic acid, 1900 ppm by weight of picolinic acid, 60 ppm by weight of Kordex MXL, and 0.2 weight percent of the cubic ceria abrasive particles prepared as described above in Example 1. The pH of the concentrate was adjusted to 4.

[0188] The concentrates were diluted with deionized water to obtain four polishing compositions. Composition 18A was obtained by diluting 1 part of the concentrate with 3 parts of deionized water. Composition 18B was obtained by diluting 1 part of the concentrate with 7 parts of deionized water. Composition 18C was obtained by diluting 1 part of the concentrate with 11 parts of deionized water. Composition 18D was obtained by diluting 1 part of the concentrate with 29 parts of deionized water.

[0189] Blanket HDP wafers were polished for 30 seconds, and patterned Silyb STI1 5k HDP filler wafers were polished to 100% overpolish on an Applied Materials Reflexion® tool and a NexPlanar® E6088 polishing pad at a platen speed of 100 rpm, a head speed of 95 rpm, downforces of 3 and 1.7 psi (20684.28 and 11721.092 Pa), and a slurry flow rate of 200 ml / min, while ex-situ conditioning was performed using a Saesol DS8051 conditioner at a downforce of 6 lbs (2.7126 kg) for 12 seconds. The patterned wafers were polished at a downforce of 1.7 psi (11721.092 Pa).

[0190] The polishing results are shown in Table 18. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Dishing and SiN loss are listed in units of angstroms (Å (0.1 nm)). Table 18 [Table 19]

[0191] As is evident from the data set forth in Table 18, high HDP removal rates and excellent topography (low dishing and low SiN loss) can be achieved with highly diluted compositions having very low concentrations of cubic ceria (50 ppm by weight of cubic ceria in this example).

[0192] Example 19 Four polishing compositions were prepared to evaluate the effect of succinylated epsilon polylysine on TEOS, SiN, and polysilicon removal rates. Each polishing composition contained 0.05 weight percent cubic ceria abrasive particles prepared as described in Example 1, 500 weight ppm picolinic acid, 169 weight ppm acetic acid, 75 weight ppm PVP (500 g / mol), 100 weight ppm Kordex MLX, and 25 or 60 weight ppm cationic polymer at pH 4. Compositions 19A and 19B contained 25 and 60 weight ppm polyquaternium-7. Compositions 19C and 19D contained 25 and 60 weight ppm 40% succinylated epsilon polylysine (derivatized polylysine having a degree of derivatization of 0.4 as described in more detail in Example 1 of U.S. Provisional Patent Application No. 62 / 958,033).

[0193] Blanket TEOS, SiN, and polysilicon wafers were polished in an Applied Materials Mirra® polishing tool using an E6088 polishing pad under the polishing conditions described above. The polishing results are shown in Table 19. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Table 19 [Table 20]

[0194] As is evident from the results reported in Table 19, high TEOS removal rates and TEOS:SiN and TEOS:polySi selectivities can be achieved in compositions containing at least 60 ppm by weight of 40% succinylated εPLL cationic polymer, indicating that succinylated polylysine cationic polymer can provide a larger dose window than, for example, polyquaternium-7.

[0195] Example 20 Five polishing compositions were prepared to evaluate the effect of succinylated epsilon polylysine on TEOS and SiN-PE removal rates. Compositions 20A-20D were prepared by combining the A pack with deionized water and the corresponding B pack as described above in Example 5. Composition 20E was prepared as a one-pack composition. The final composition contained 750 ppm by weight picolinic acid, 169 ppm by weight acetic acid, 50 ppm by weight benzisothiazolinone, 70 ppm by weight 40% succinylated epsilon polylysine (i.e., having a degree of derivatization of 0.4 as noted in Example 19), 30 ppm by weight Kordex MLX at pH 4, and either 0.063 weight percent (Compositions 20A, 20B, and 20E) or 0.2 weight percent (Compositions 2C and 2D) weight percent ceria.

[0196] The A-packs contained 7500 ppm by weight of picolinic acid, 300 ppm by weight of Kordek MLX, and 0.63 weight percent (20A and 20B) or 2.0 weight percent (20C and 20D) of ceria abrasive particles. Compositions 20A and 20C used the sintered ceria abrasive used in polishing composition 1C of commonly assigned U.S. Patent No. 9,505,952, while compositions 20B and 20D used the raw ceria dispersion described in Example 1. The pH of each A-pack was approximately 4. The B-packs contained 563 ppm by weight of acetic acid, 233 ppm by weight of 40% succinylated epsilon polylysine, and 166 ppm of benzisothiazolinone, respectively. The pH of each B-pack was approximately 4.

[0197] Blanket TEOS and SiN-PE wafers were polished for 30 seconds in a Logitech polishing tool under the conditions listed above for the Mirra® tool. The polishing results are shown in Table 20. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Table 20 [Table 21]

[0198] As is evident from the data set forth in Table 20, compositions containing cubic ceria and succinylated epsilon-polylysine (20B and 20D) of the present invention achieved significantly higher TEOS removal rates (2x) than compositions containing calcined ceria (20A and 20C). Additionally, the one-pack composition (20E) performed similarly to the corresponding two-pack composition (20B).

[0199] Example 21 Seven polishing compositions were prepared to evaluate the effect of pH on TEOS and SiN-PE removal rates and dishing performance. Compositions 21A-21G were prepared by mixing the A pack and the corresponding B pack on a platen in a ratio of 7 parts A to 3 parts B. The A packs each contained 800 ppm by weight of cubic ceria obtained from the raw ceria dispersion described in Example 1 and 1100 ppm by weight of picolinic acid at pH 4. The B packs contained either 166 ppm by weight of polyquaternium-7 (21A and 21B) or 250 ppm of succinylated epsilon polylysine (21C, 21D, 21E, 21F, and 21G) described in Example 19. The B packs for compositions 21C and 21D further contained 312 ppm by weight of polyvinylpyrrolidone. The pH of B packs 21A, 21C, and 21E was 4. The pH of B-packs 21B, 21D, and 21F was 5. The pH of B-pack 21G was 6. Table 21A summarizes the point-of-use polishing compositions. Table 21A [Table 22]

[0200] Blanket TEOS wafers were polished for 30 seconds, blanket SiN-PE wafers were polished for 60 seconds, and patterned Silyb STI1 2.3k HDP filled wafers were polished to an endpoint of +50% using an Applied Materials Reflexion® tool and a NexPlanar® E6088 polishing pad with a platen speed of 93 rpm, a head speed of 87 rpm, a downforce of 3 psi (20684.28 Pa), and a slurry flow rate of 250 ml / min, while in situ conditioning was performed using a Saesol DS8051 conditioner with a downforce of 6 lbs (2.7126 kg). The polishing results are shown in Table 21B. All removal rates are listed in angstroms per minute (Å (0.1 nm) / min). Dishing is listed in angstroms (Å (0.1 nm)). Table 21B [Table 23]

[0201] As is evident from the data set forth in Table 21B, high TEOS removal rates, low SiN removal rates (and therefore high TEOS:SiN selectivity), and low dishing can be achieved at pH values ​​that can be up to and exceed pH 5.

[0202] The use of the terms "a," "an," and "the" and similar referents in the context of describing the present invention (particularly in the context of the claims below) should be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise stated. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within that range, unless otherwise indicated herein, and each separate value is incorporated herein as if it were individually recited herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to further elucidate the invention and does not pose a limitation on the scope of the invention, unless otherwise expressly claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0203] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments may become apparent to those skilled in the art upon reading the above detailed description. The inventors expect skilled artisans to employ such variations as they see fit, and the inventors also contemplate the invention being practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Also, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0204] It will be appreciated that the present disclosure includes many embodiments beyond those included above in the examples, including, but not limited to, those set forth in the appended claims. Some embodiments of the present invention are described below. [Aspect 1] Liquid carrier; cubic ceria abrasive particles dispersed in the liquid carrier; and Cationic polymers with charge densities greater than about 6 milliequivalents per gram (meq / g) 1. A chemical-mechanical polishing composition comprising: [Aspect 2] 2. The composition of embodiment 1, wherein the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide. [Aspect 3] The composition of embodiment 1, wherein the cubic ceria abrasive particles have a molar ratio of lanthanum to lanthanum plus cerium in the range of about 1 to about 15 percent. [Aspect 4] The cubic ceria abrasive particles are about 3 m 2 / g ~ approx. 14m 2 / g。 The composition of embodiment 1, having a BET surface area in the range of. [Aspect 5] 2. The composition of embodiment 1, wherein the cubic ceria abrasive particles have an average particle size in the range of about 50 nm to about 500 nm. [Aspect 6] 2. The composition of embodiment 1, comprising from about 0.001 to about 1 weight percent of the cubic ceria abrasive particles at the point of use. [Aspect 7] 2. The composition of embodiment 1, wherein the cationic polymer has a charge density greater than about 9 meq / g. [Aspect 8] 2. The composition of embodiment 1, wherein the cationic polymer comprises at least one of poly(vinylimidazole), poly(vinylimidazolium), poly(vinylmethylimidazolium), epichlorohydrin-dimethylamine, polydiallyldimethylammonium, poly(vinylmethylimidazolium) methylsulfate, polyethyleneimine, polylysine, polyhistidine, and polyarginine. [Aspect 9] 2. The composition of embodiment 1, wherein the cationic polymer is poly(vinylimidazolium), polylysine, or a mixture thereof. [Aspect 10] 2. The composition of embodiment 1, comprising from about 0.1 ppm to about 20 ppm by weight of the cationic polymer at the point of use. [Aspect 11] 2. The composition of embodiment 1, comprising from about 1 ppm to about 10 ppm by weight of the cationic polymer at the point of use. [Aspect 12] 10. The composition of embodiment 1, further comprising a carboxylic acid-silicon oxide polishing rate enhancer. [Aspect 13] Aspect 13. The composition of aspect 12, wherein the carboxylic acid is picolinic acid, acetic acid, 4-hydroxybenzoic acid, or a mixture thereof. [Aspect 14] The composition of embodiment 1, having a pH within the range of about 3 to about 6 at the time of use. [Aspect 15] about 0.001 to about 1 weight percent of the cubic ceria abrasive particles at the point of use; and About 0.1 ppm by weight to about 20 ppm by weight of poly(vinylimidazolium), polylysine, or a mixture thereof at the time of use 2. The composition of embodiment 1, comprising: [Aspect 16] 16. The composition of embodiment 15, having a pH at the time of use in the range of about 3 to 6, and further comprising picolinic acid, acetic acid, or a mixture thereof. [Aspect 17] At the point of use, the cubic ceria abrasive particles comprise from about 0.001 to about 1 weight percent: the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size within the range of about 50 to about 500 nm; the cationic polymer comprises poly(vinylimidazolium), polylysine, or a mixture thereof; 2. The composition of embodiment 1. [Aspect 18] 18. The composition of embodiment 17, having a pH at the time of use in the range of about 3 to 6, and further comprising picolinic acid, acetic acid, or a mixture thereof. [Aspect 19] 1. A method of chemical mechanical polishing a substrate comprising a silicon oxide dielectric material, comprising: (a) applying a polishing composition comprising a liquid carrier; cubic ceria abrasive particles dispersed in the liquid carrier; and a cationic polymer having a charge density greater than about 6 meq / g; (b) contacting the substrate with the applied polishing composition; (c) moving the polishing composition relative to the substrate; and (d) polishing the substrate by abrading the substrate to remove a portion of the silicon oxide dielectric material from the substrate. A method comprising: [Aspect 20] 20. The method of embodiment 19, wherein the removal rate of the silicon oxide dielectric material is greater than about 6000 Å / min. [Aspect 21] 20. The method of embodiment 19, wherein the cationic polymer is polylysine or poly(vinylimidazolium). [Aspect 22] the polishing composition, at the point of use, comprises from about 0.001 to about 1 weight percent of the cubic ceria abrasive particles; the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size within the range of about 50 to about 500 nm; 20. The method of embodiment 19. [Aspect 23] 20. The method of embodiment 19, wherein the polishing composition further comprises picolinic acid, acetic acid, or a mixture thereof.

Claims

1. liquid carrier; cubic ceria abrasive particles dispersed in the liquid carrier; and Cationic polymers having a charge density greater than 6 milliequivalents per gram (meq / g) 1. A chemical-mechanical polishing composition for polishing a substrate comprising a silicon oxide dielectric material, comprising: the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide; The chemical-mechanical polishing composition, wherein the cubic ceria abrasive particles are present in an amount of 0.001 to 1 weight percent at the time of use, and the cationic polymer is poly(vinylimidazolium) methyl sulfate, poly(vinylmethylimidazolium) methyl sulfate, acrylamide copolymer of polyDADMAC, polydiallyldimethylammonium, polylysine, poly(vinylimidazolium), or poly(vinylmethylimidazolium).

2. 10. The composition of claim 1, wherein the cubic ceria abrasive particles have a molar ratio of lanthanum to lanthanum plus cerium within the range of 1 to 15 percent.

3. The cubic ceria abrasive particles are 3 m 2 / g~14m 2 10. The composition of claim 1, having a BET surface area in the range of 100 / g.

4. 10. The composition of claim 1, wherein the cubic ceria abrasive particles have an average particle size in the range of 50 nm to 500 nm.

5. 10. The composition of claim 1, wherein the cationic polymer has a charge density greater than 9 meq / g.

6. 2. The composition of claim 1, wherein the cationic polymer is poly(vinylimidazolium), poly(vinylmethylimidazolium), polydiallyldimethylammonium, poly(vinylmethylimidazolium) methyl sulfate, or polylysine.

7. The composition of claim 1 , wherein the cationic polymer is poly(vinylimidazolium) or polylysine.

8. 10. The composition of claim 1, comprising from 0.1 ppm to 20 ppm by weight of said cationic polymer at the point of use.

9. 10. The composition of claim 1, comprising from 1 ppm to 10 ppm by weight of said cationic polymer at the point of use.

10. The composition of claim 1 further comprising a carboxylic acid-silicon oxide polishing rate enhancer.

11. The composition of claim 10, wherein the carboxylic acid is picolinic acid, acetic acid, 4-hydroxybenzoic acid, or a mixture thereof.

12. 10. The composition of claim 1, having a pH in the range of 3 to 6 at the time of use.

13. 10. The composition of claim 1, comprising from 0.1 ppm to 20 ppm by weight of poly(vinylimidazolium) or polylysine at the point of use.

14. 14. The composition of claim 13, having a pH in the range of 3 to 6 at the time of use, and further comprising picolinic acid, acetic acid, or a mixture thereof.

15. the cubic ceria abrasive particles have an average particle size in the range of 50 to 500 nm; the cationic polymer is poly(vinylimidazolium) or polylysine; The composition of claim 1.

16. 16. The composition of claim 15, having a pH in the range of 3 to 6 at the time of use, and further comprising picolinic acid, acetic acid, or a mixture thereof.

17. 1. A method of chemical mechanical polishing a substrate comprising a silicon oxide dielectric material, comprising: (a) providing a polishing composition comprising: a liquid carrier; cubic ceria abrasive particles dispersed in the liquid carrier; and a cationic polymer having a charge density greater than 6 meq / g; (b) contacting the substrate with the provided polishing composition; (c) moving the polishing composition relative to the substrate; and (d) polishing the substrate by abrading the substrate to remove a portion of the silicon oxide dielectric material from the substrate. A method comprising: the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide; The method, wherein the polishing composition contains, at the point of use, 0.001 to 1 weight percent of the cubic ceria abrasive particles, and the cationic polymer is poly(vinylimidazolium) methyl sulfate, poly(vinylmethylimidazolium) methyl sulfate, acrylamide copolymer of polyDADMAC, polydiallyldimethylammonium, polylysine, poly(vinylimidazolium), or poly(vinylmethylimidazolium).

18. 18. The method of claim 17, wherein the removal rate of the silicon oxide dielectric material is greater than 6000 Å / min.

19. 18. The method of claim 17, wherein the cationic polymer is polylysine or poly(vinylimidazolium).

20. 18. The method of claim 17, wherein the cubic ceria abrasive particles have an average particle size in the range of 50 to 500 nm.

21. 18. The method of claim 17, wherein the polishing composition further comprises picolinic acid, acetic acid, or a mixture thereof.

Images