Composition and method for selective oxide cmp

Abstract

To provide a chemical mechanical polishing composition for polishing a substrate having a silicon oxygen material (e.g., silicon oxide).SOLUTION: A chemical mechanical polishing composition for polishing a substrate having a silicon oxygen material includes a liquid carrier, cubiform abrasive particles dispersed in the liquid carrier, and at least one of an anionic compound and a nonionic compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 62 / 924,352, filed October 22, 2019, entitled "Composition and Method for Selective Oxide CMP." [Background technology]

[0002] Chemical-mechanical polishing is a key enabling technology in the fabrication of integrated circuits (ICs) and microelectromechanical systems (MEMS). CMP compositions and methods for polishing (or planarizing) the surface of a substrate (e.g., a wafer) are well known to those skilled 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 to increase material removal rates, improve planarization efficiency, and / or reduce defectivity during CMP operations.

[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 polishing compositions are widely used for advanced dielectric applications, including shallow trench isolation applications. Although the use of ceria abrasives is known, there remains a need for improved ceria abrasive-based CMP compositions. Specifically, there remains a need for CMP compositions that improve removal rates and improve planarization (e.g., reduce erosion and dishing). Furthermore, there remains a need for removal rate selectivity of one silicon-containing material relative to another silicon-containing material (e.g., selectivity of silicon oxide over silicon nitride, or selectivity of silicon oxide over polysilicon). Summary of the Invention [Means for solving the problem]

[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 abrasive particles dispersed in the liquid carrier, and at least one of an anionic compound and a nonionic compound.

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

[0006] [Figure 1] 1 and 2 are transmission electron microscopy (TEM) micrographs of cubic ceria abrasive samples showing square-faceted ceria abrasive particles. [Figure 2] 1 and 2 are transmission electron microscopy (TEM) micrographs of cubic ceria abrasive samples showing square-faceted ceria abrasive particles. [Figure 3] FIG. 3 is a scanning electron microscopy (SEM) micrograph of a cubic ceria abrasive sample showing square-faceted ceria abrasive particles. DETAILED DESCRIPTION OF THE INVENTION

[0007] A chemical-mechanical polishing composition for polishing substrates having silicon-oxygen materials (e.g., silicon oxide) is disclosed. The polishing composition comprises, consists of, or consists essentially of a liquid carrier, cubic abrasive particles dispersed in the liquid carrier, and at least one of an anionic compound and a nonionic compound. In one embodiment, the polishing composition comprises an anionic polymer, such as poly(acrylic acid), poly(methacrylic acid), and / or poly(vinyl sulfonic acid). In another embodiment, the polishing composition comprises a non-polymeric anionic compound, such as 4-dodecylbenzene sulfonic acid. In yet another embodiment, the polishing composition comprises a non-ionic polymer, such as polyvinylpyrrolidone or poly(vinylpyrrolidone-co-vinyl acetate).

[0008] The disclosed polishing compositions and corresponding (CMP methods) can provide significant and unexpected advantages. For example, the disclosed compositions can significantly improve silicon oxide removal rates, thereby improving throughput and saving time and costs. The disclosed compositions can also improve selectivity to silicon nitride and / or polysilicon layers, thereby providing additional process flexibility.

[0009] The polishing composition contains abrasive particles comprising cubic ceria abrasive particles suspended in a liquid carrier. By "cubic," it is meant that the ceria abrasive particles are in the form or shape of a cube, i.e., approximately cubic. In other words, the cubic ceria abrasive particles are cubic in shape and nature. However, it should be understood that the edge dimensions, corners, and corner angles need not be exactly or precisely perfect cubic. For example, cubic abrasive particles can 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 minor irregularities and still maintain the basic shape of a cube. As can be readily seen by one skilled in the art (e.g., via scanning electron microscopy or transmission electron microscopy), cubic ceria abrasive particles are generally cubic in shape, with allowances made for grain growth and deagglomeration.

[0010] Figures 1, 2, and 3 show examples of cubic ceria abrasive particles. These transmission electron microscopy (TEM) and SEM images show ceria abrasive particles with square faces. For example, in these images, the particle faces shown each include four edges that have approximately the same length (e.g., within 20% of each other, or within 10 percent of each other, or less). Furthermore, the edges meet at the corners at approximately 90-degree angles (e.g., within a range of about 80 to 100 degrees, or within a range of about 85 to 95 degrees). As will be apparent to those skilled in the art, the TEM and SEM images show that the majority of the abrasive particles shown are cubic in that they have square faces as defined above. Some of the particles may be observed to contain defects, for example, on one or more corners. Again, the term cubic is not intended to refer to ceria abrasive particles that are precisely cubic, but rather to particles that are essentially roughly cubic, as defined 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 percent of the abrasive particles are essentially cubic (cubic in form or shape, as described above). In preferred embodiments, at least 40 percent (e.g., at least 60 percent, or at least 80 percent) of the abrasive particles are essentially cubic. As noted above, cubic ceria abrasive particles can be easily evaluated and counted using TEM or SEM images, for example, at magnifications of about 10,000x to about 500,000x. Abrasive particles shown in SEM or TEM images have faces with four sides of similar length (e.g., within 20 percent of each other). The images also show that adjacent sides are nearly perpendicular, forming angles of, for example, about 90 degrees (e.g., in the range of about 80 degrees to 100 degrees). To determine whether a ceria polishing composition contains cubic ceria abrasive particles, a large number of randomly selected particles (i.e., 200 or more) should be observed by SEM or TEM to perform a statistical analysis and thereby determine the percentage of particles with square faces. Retained particles should have images that are clearly visible on the micrograph. Some of the particles may exhibit some defects on the particle surface and / or one or more of the particle corners, but can still be counted as cubic.

[0012] The cubic ceria abrasive particles may be substantially pure ceria abrasive particles (within normal tolerances for impurities) or may be doped ceria abrasive particles. Doped ceria abrasive particles may contain interstitial dopants (dopants that occupy spaces in the lattice that are not normally occupied) or substitutional dopants (dopants that occupy 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 comprise one or more lanthanides, including, for example, lanthanum, praseodymium, neodymium, promethium, samarium, and the like. In a particularly preferred embodiment, the cubic ceria abrasive particles comprise a mixed oxide of cerium and lanthanum. The molar ratio of La to (La+Ce) in the mixed oxide abrasive particles may be from about 0.01 to about 0.15, e.g., from about 0.01 to about 0.12. Of course, such abrasive particles may additionally contain other elements and / or oxides (e.g., as impurities). Such impurities may originate from raw or starting materials used during the abrasive particle preparation process. The total proportion of impurities is preferably less than 0.2% by weight of the particle. Residual nitrates are not considered impurities.

[0014] In certain embodiments, the molar ratio of La to (La + Ce) may be from about 0.01 to about 0.04 (e.g., from about 0.02 to about 0.03). In one such embodiment, the cubic ceria abrasive particles contain about 2.5 mol % lanthanum oxide and about 97.5 mol % cerium oxide. In other embodiments, the molar ratio may be from about 0.08 to about 0.12 (e.g., from about 0.09 to about 0.11). In one such embodiment, the cubic ceria abrasive particles contain about 10 mol % lanthanum oxide and about 90 mol % cerium oxide. The abrasive particles may be a single-phase solid solution, in which lanthanum atoms substitute for cerium atoms in the cerium oxide crystal structure. In one embodiment, the solid solution exhibits a symmetrical X-ray diffraction pattern, with peaks located between about 27 degrees and about 29 degrees, shifted to smaller angles than pure cerium oxide. A solid solution can be obtained when the temperature in the aging substep (described below) is above about 60°C. As used herein, the term "solid solution" means that X-ray diffraction shows only the cerium oxide crystal structure pattern, regardless of whether or not individual peaks are shifted, but without additional peaks that would indicate the presence of other phases.

[0015] The cubic ceria abrasive particles may optionally be characterized by their specific surface area, 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 specific surface area of ​​the abrasive particles ranges from about 3 to about 14 m. 2 / g (e.g., about 7 to about 13 m 2 / g, or about 8 to about 12 m 2 / g).

[0016] The cubic ceria abrasive particles can also be optionally characterized by their average particle size and / or particle size distribution. The average particle size of the abrasive particles can be 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). Furthermore, the average particle size can be greater than about 50 nm (e.g., greater than about 80 nm or greater than about 100 nm). The average particle size can be determined via dynamic light scattering (DLS) and corresponds to the median particle size (D50). DLS measurements can be performed, for example, using a Zetasizer (available from Malvern Instruments). As will be apparent to those skilled in the art, DLS measurements can significantly undercount small particles when measured in the presence of larger particles. For the cubic ceria abrasive particles disclosed herein, the DLS technique tends to undercount particles less than about 40 nm. Of course, the disclosed embodiments may contain many 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 can also be optionally used to characterize the particle size distribution. As will be apparent to those skilled in the art, laser diffraction techniques also tend to undercount small particles (e.g., less than about 40 nm in the disclosed embodiments). Laser diffraction measurements can be performed, for example, using a Horiba LA-960 with a relative refractive index of 1.7. Various parameters can be obtained from the distribution obtained by laser diffraction measurements, including, for example, D10, D50, D90, D99, and the dispersion index (defined below). Based on laser diffraction measurements, the abrasive particles may have a median diameter (D50) of about 100 nm to about 700 nm (e.g., about 100 nm to about 200 nm). For example, the D50 may be 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 may optionally have a D10 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). Needless to say, D10 is the particle size determined by laser diffraction, and is the particle size at which 10% of the particles have a diameter less than D10.

[0019] The D90 of the cubic ceria abrasive particles may optionally be 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 is the particle size determined by laser diffraction, and represents the particle size at which 90% of the particles have a diameter less than D90. Mechanically deagglomerated abrasive particles may have a D90 of less than about 300 nm.

[0020] The cubic ceria abrasive particles can optionally exhibit a low dispersion index. The "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. The dispersion index of mechanically deagglomerated abrasive particles may be less than about 0.30. Furthermore, the D90 / D50 may be from about 1.3 to about 2 for the mechanically deagglomerated particles.

[0021] The D99 of the cubic ceria abrasive particles may optionally be 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). The D99 of mechanically deagglomerated abrasive particles may be less than about 600 nm (e.g., less than about 500 or about 400 nm). D99 is the particle size determined by laser diffraction and represents the particle size at which 99% of the particles have diameters less than D99.

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

[0023] In one advantageous embodiment, cubic cerium-lanthanum oxide abrasive particles can be prepared by precipitating cerium and lanthanum nitrates. One such preparation method comprises the following steps: (i) mixing an aqueous solution of cerium nitrate with an aqueous base under an inert atmosphere; (ii) heating the mixture obtained in (i) under an inert atmosphere; (iii) optionally acidifying the heat-treated mixture obtained in (ii); (iv) washing the solid material obtained in (ii) or (iii) with water; (v) mechanically treating the solid material obtained in (iv) to deagglomerate the ceria particles; Includes:

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

[0025] Step (i) involves mixing / reacting an aqueous cerium nitrate solution with an aqueous base. Hydroxide-type bases, including, for example, hydroxides of alkali metals or alkaline earth metals 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 can be performed by introducing the aqueous cerium nitrate solution into the aqueous base. Mixing is performed under an inert atmosphere, for example, in a closed or semi-closed reactor with an inert gas (e.g., nitrogen or argon) purge. Mixing may be performed with stirring. The molar ratio of base to (Ce+La) may be about 8.0 to about 30.0 (e.g., greater than about 9.0). Step (i) may further be performed at a temperature of 5°C to about 50°C, for example, about 20°C to 25°C.

[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 of 75°C to about 95°C, for example, about 85°C to about 90°C. The aging substep may involve maintaining (holding) the mixture at that temperature for about 2 hours to about 20 hours. Generally, the aging time decreases as the temperature increases. Step (ii) may also be carried out with stirring under an inert atmosphere, as described above for step (i).

[0027] In step (iii), the mixture obtained at the end of step (ii) can optionally be acidified, for example, using nitric acid. The heat-treated reaction mixture can be acidified, for example, to a pH of less than about 3.0 (e.g., 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 can reduce residual nitrates in the final dispersion and achieve the target conductivity. Washing can include filtering the solid from the mixture and redispersing the solid in water. Filtration and redispersion can be performed several times if necessary.

[0029] In step (v), the washed solid material obtained in (iv) can be optionally mechanically treated to deagglomerate or partially deagglomerate the ceria abrasive particles. Mechanical treatments, including, for example, double jet or ultrasonic deagglomeration, typically result in a narrow particle size distribution and a reduced number of large agglomerates.

[0030] After step (iv) or (v), the solid material can be dried to obtain the cerium-based particles in powder form. The powder can be redispersed by adding water or a mixture of water and a miscible liquid organic compound, thereby obtaining a dispersion of the cerium-based particles in a liquid medium. The liquid medium can be water or a mixture of water and a water-miscible organic liquid. The water-miscible organic liquid can include, for example, alcohols such as isopropyl 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 can be 80:20 to 99:1 parts by weight. Furthermore, the dispersion can 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 also have a conductivity of less than about 300 μS / cm, such as less than about 150 μS / cm, more specifically less than 150 μS / cm, or less than about 100 μS / cm.

[0031] The polishing composition may contain virtually any suitable amount of cubic ceria abrasive particles. For example, the polishing composition may contain about 0.001 weight percent or more (e.g., 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 point of use. The polishing composition may contain about 5 weight percent or less (e.g., about 2 weight percent or less, about 1.5 weight percent or less, or about 1 weight percent or less) of cubic ceria abrasive particles at the point of use. Of course, the cubic ceria abrasive particles may be present in the polishing composition at a concentration bounded by any two of the aforementioned endpoints. For example, the concentration of cubic ceria abrasive particles in the polishing composition at the point of use may be about 0.001 weight percent to about 5 weight percent (e.g., about 0.01 weight percent to about 2 weight percent, about 0.05 weight percent to about 1.5 weight percent, or about 0.1 weight percent to about 1 weight percent).

[0032] An 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 wt% water (e.g., deionized water). The liquid carrier may include other suitable non-aqueous carriers, including 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 weakly acidic, neutral, or alkaline, having a pH of about 4 to about 11. For example, the pH of the polishing composition may be about 5 to about 10. In one embodiment, the polishing composition is weakly acidic, having a pH of about 4 to about 7 (e.g., about 4 to about 6, or about 4.5 to about 6). For example, in such a weakly acidic embodiment, the pH may be about 5. In another embodiment, the polishing composition is alkaline, having a pH of about 8 to about 11 (e.g., about 9 to about 11, or about 9 to about 10.5, or about 9.5 to about 10.5). For example, in such an alkaline embodiment, the pH may be about 10. In yet another embodiment, the polishing composition is neutral, having a pH of about 6 to about 8 (e.g., about 6.5 to about 7.5).

[0034] The polishing composition may further contain a chemical additive. The chemical additive associates with the surface of the cubic ceria abrasive particles and / or with the surface of the substrate being polished (e.g., via electrostatic interactions and / or hydrogen bonding). The chemical additive may be, for example, a dispersant, a rheological agent, a polishing rate enhancer, a polishing rate suppressor, or a selectivity enhancer (to improve the removal rate ratio of one material to another). Preferred chemical additives include anionic compounds (e.g., anionic polymers and anionic surfactants) and nonionic compounds, such as nonionic polymers.

[0035] Suitable anionic compounds may include anionic polymers and non-polymeric anionic compounds (e.g., surfactants). The anionic compounds may include water-soluble polyelectrolytes, polyanions, polyacids, polyacrylates, poly(vinyl acids), anionic detergents, alkyl or alkyl ether sulfonates and sulfates, alkyl or alkyl ether phosphonates and phosphates, and alkyl or alkyl ether carboxylates.

[0036] Anionic polymers may be homopolymers or copolymers and may contain monomer units selected from carboxylic acid groups, sulfate or sulfonic acid groups, and phosphate or phosphonic acid groups. Suitable anionic polymers may include poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(vinyl sulfate), poly(vinyl phosphoric acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), and combinations thereof. Anionic compounds may include sodium and ammonium salt versions of the above-mentioned compounds (e.g., poly(methacrylic acid, sodium salt)). Anionic compounds may also include derivatives of the above-mentioned compounds, for example, in which one or more alkyl groups or other functional groups are included within the compound. For example, poly(methacrylic acid) is a derivative of poly(acrylic acid).

[0037] Examples of anionic polymers may further include copolymers containing one or more of acrylic acid, methacrylic acid, maleic acid, vinyl sulfonic acid, sulfate, styrene sulfonic acid, and phosphate monomers. Such anionic polymers may optionally contain one or more nonionic monomers. Nonionic monomers include, but are not limited to, methacrylate esters, vinyl acetate, acrylamide, and N-vinylpyrrolidone. Examples of copolymers may include poly(methyl methacrylate-co-methacrylic acid), poly(acrylamide-co-acrylic acid), poly(4-styrene sulfonic acid-co-maleic acid), and poly(acrylic acid-co-maleic acid).

[0038] The non-polymeric anionic compound may include alkyl or alkylaryl sulfates, alkyl or alkylaryl sulfonates, alkyl or alkylaryl phosphates, alkyl or alkylaryl carboxylates, or combinations thereof. Examples of anionic compounds include dodecylbenzenesulfonic acid, ammonium lauryl sulfate, 1-decanesulfonate, stearic acid, dihexadecylphosphate, dodecylphosphonic acid, and combinations thereof, ammonium and sodium salt versions thereof, and derivatives thereof.

[0039] Suitable nonionic compounds may include water-soluble nonionic polymers and non-polymeric nonionic compounds. The nonionic compounds may include water-soluble polyethers, polyether glycols, alcohol ethoxylates, polyoxyalkylene alkyl ethers, polyesters, vinyl acrylates, or combinations thereof.

[0040] The nonionic polymer may be a homopolymer or copolymer and may contain virtually any suitable nonionic monomer unit. Examples of nonionic polymers include polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, poly(vinyl phenyl ketone), poly(vinyl pyridine), poly(vinylimidazole), 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 foregoing monomer units. Examples of copolymers include poly(vinyl acetate-co-methyl methacrylate), poly(vinyl pyrrolidone-co-vinyl acetate), and poly(ethylene-co-vinyl acetate).

[0041] Nonionic compounds may include derivatives of the above compounds, for example, where one or more alkyl groups or other functional groups are included within the compound. For example, poly(N-isopropylacrylamide) is a derivative of poly(acrylamide).

[0042] The polishing composition may contain substantially any suitable amount of anionic and / or nonionic compounds. For example, the polishing composition may contain about 100 ppm (0.01 percent by weight) or more (e.g., about 250 ppm by weight or more, about 500 ppm by weight or more, about 750 ppm by weight or more, about 1000 ppm by weight (0.1 percent by weight) or more) of anionic and / or nonionic compounds at the point of use. The polishing composition may contain about 2% by weight or less (e.g., about 1.5% by weight or less, about 1.2% by weight or less, or about 1% by weight or less) of anionic and / or nonionic compounds at the point of use. Of course, the anionic and / or nonionic compounds may be present in the polishing composition at a concentration separated by any two of the aforementioned endpoints. For example, the concentration of the anionic and / or nonionic compound in the polishing composition may be about 0.01% to about 2% by weight (about 0.05% to about 1.5% by weight, or about 0.1% to about 1% by weight) at the point of use.

[0043] The polishing composition may further contain other optional additives, such as secondary polishing rate accelerators or inhibitors, dispersants, conditioners, scale inhibitors, chelating agents, stabilizers, pH adjusting and buffering compounds, 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.

[0044] The polishing composition may optionally further comprise a biocide. The biocide may comprise substantially any suitable biocide, such as an isothiazolinone biocide, such as methylisothiazolinone or benzisothiazolone. The amount of biocide in the polishing composition is typically about 1 ppm to about 100 ppm by weight, e.g., about 5 ppm to about 75 ppm by weight, at the point of use.

[0045] Polishing compositions can be prepared using any suitable technique. Many of these techniques are known to those skilled in the art. Polishing compositions can be prepared by batch or continuous processes. Broadly speaking, polishing compositions can be prepared by combining their components in any order. As used herein, "component" includes individual ingredients (e.g., abrasive grains, anionic and / or nonionic compounds, and optional additives). For example, anionic and / or nonionic compounds can be added to an aqueous carrier (e.g., water) at a desired concentration. The pH can then be adjusted (as desired), and cubic ceria abrasives can be added at a desired concentration to form the polishing composition. Polishing compositions can be prepared before use, in which case one or more components are added to the polishing composition immediately before use (e.g., within about 1 minute before use, within about 1 hour before use, or about 1 day or about 7 days before use). Polishing compositions can also be prepared by mixing the components on the substrate surface during polishing (e.g., on a polishing pad).

[0046] In certain embodiments, the polishing composition can be provided as a "two-pack" system. For example, the first pack can contain the cubic ceria abrasive and other optional ingredients, and the second pack can contain the anionic and / or nonionic compound and other optional ingredients. The first and second packs can be shipped separately and combined on the polishing pad prior to polishing (within an hour or a day of polishing) or during the CMP operation.

[0047] The polishing composition of the present invention may be provided as a concentrate. The concentrate is intended to be diluted with an appropriate amount of water before use. In such an embodiment, the polishing composition concentrate can contain cubic ceria abrasive particles and the other components described above in amounts such that, when the concentrate is diluted 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 described above for each component. For example, the cubic ceria abrasive particles, the self-stopping agent, the cationic polymer, and other optional additives can 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) the point-of-use concentration described above for each component, so that when the concentrate is diluted with an equal volume (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 described above for each component.

[0048] In embodiments in which the polishing composition is provided as a two-pack system, one or both packs are 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, which contains cubic ceria abrasive particles at a concentration about three times (e.g., about five times, about eight times, about ten times, about fifteen times, or about twenty times) higher than the point-of-use concentration described above. The concentrated first pack can be mixed with an appropriate amount of water before combining with the second pack. Similarly, the second pack is provided as a concentrate, which contains anionic and / or nonionic compounds at a concentration about three times (e.g., about five times, about eight times, about ten times, about fifteen times, or about twenty times) higher than the point-of-use concentration described above. In such embodiments, the concentrated second pack can be mixed with an appropriate amount of water before combining with the first pack. In certain embodiments, both the first pack and the second pack can be diluted with water before combining. The disclosed embodiments are not limited in this respect.

[0049] The polishing method of the present invention is particularly suitable for use in conjunction with a chemical mechanical polishing (CMP) apparatus, for example, including a platen and a pad fixed to the platen. As known to those skilled in the art, polishing of a substrate occurs when the substrate is brought into contact with a polishing pad and the polishing composition of the present invention, and then at least a portion of the substrate is ground away by moving the polishing pad and the substrate relative to each other. The method of the present invention comprises preparing the composition of the present invention, contacting a substrate (e.g., a wafer) with the polishing composition of the present invention, moving the polishing composition relative to the substrate, and grinding the substrate, thereby removing a portion of the silicon oxide material from the substrate and polishing the substrate.

[0050] The substrate generally includes a patterned dielectric layer, many of which are well known. The patterned dielectric layer includes various forms of silicon oxide and silicon oxide-based dielectric materials. For example, the dielectric materials, including silicon oxide and silicon oxide-based dielectric layers, include, consist of, or consist essentially of tetraethyl orthosilicate (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-assisted tetraethyl orthosilicate (PETEOS), thermal oxide, or undoped silicate glass.

[0051] The polishing composition can desirably exhibit 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-assisted tetraethyl orthosilicate (PETEOS), spin-on glass (SOG), and / or tetraethyl orthosilicate (TEOS), the polishing composition can desirably exhibit a silicon oxide removal rate of about 1000 Å / min or more (e.g., about 2000 Å / min or more, about 2,500 Å / min or more, about 3,000 Å / min or more, about 3,500 Å / min or more, about 4000 Å / min or more, about 4500 Å / min or more, or about 5000 Å / min or more).

[0052] The polishing composition may also be suitable for polishing substrates containing both silicon oxide and silicon nitride materials. In certain embodiments, it may be desirable for the removal rate of the silicon oxide material to exceed the removal rate of the silicon nitride material (i.e., a removal rate selectivity of silicon oxide relative to silicon nitride greater than 1). In example embodiments, it is advantageous for the polishing composition to exhibit a removal rate selectivity of silicon oxide relative to silicon nitride greater than 2 (e.g., in certain embodiments, greater than 3, greater than 5, greater than 7, greater than 10, greater than 15, or greater than 20).

[0053] In other applications where the polishing composition is used to polish both silicon oxide and silicon nitride materials, it may be desirable for the removal rate of the silicon nitride material to exceed the removal rate of the silicon oxide material. In example embodiments, it may be advantageous for the polishing composition to exhibit a selectivity of silicon nitride over silicon oxide that is greater than 1 (i.e., the selectivity of silicon oxide over silicon nitride is less than 1).

[0054] The polishing composition may also be suitable for polishing substrates containing both silicon oxide and polysilicon materials. In certain embodiments, it may be desirable for the removal rate of the silicon oxide material to exceed the removal rate of polysilicon (i.e., a removal rate selectivity of silicon oxide relative to polysilicon greater than 1). In example embodiments, it is advantageous for the polishing composition to exhibit a removal rate selectivity of silicon oxide relative to polysilicon greater than 2 (e.g., greater than 3, greater than 5, greater than 7, greater than 10, greater than 15, or greater than 20 in certain embodiments).

[0055] The method of the present invention desirably planarizes the patterned dielectric material, for example, through reducing the initial step height between the raised regions (having an initial height) and the trench (having an initial trench thickness). To effectively and efficiently achieve this planarization, the method of the present invention desirably has a high removal rate of the raised regions (of the active pattern dielectric material) and a relatively low removal rate of the trench dielectric material. As polishing progresses, the wafer is planarized by reducing the step height between the raised regions and the trench.

[0056] Of course, the disclosure includes numerous embodiments, including but not limited to the following embodiments.

[0057] In a first embodiment, the chemical-mechanical polishing composition includes a liquid carrier, cubic abrasive particles dispersed in the liquid carrier, and at least one of an anionic compound and a nonionic compound.

[0058] A second embodiment may include the first embodiment, wherein the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide.

[0059] A third embodiment may include any one of the first and second embodiments, wherein the cubic ceria abrasive particles have a molar ratio of lanthanum to lanthanum and cerium of about 1 to about 15 percent.

[0060] A fourth embodiment may include any one of the first to third embodiments, wherein the cubic ceria abrasive particles have a BET surface area of ​​about 3 m 2 / g ~ approx. 14m 2 / g.

[0061] A fifth embodiment may include any one of the first to fourth embodiments, wherein the cubic ceria abrasive particles have an average particle size of about 50 to about 500 nm.

[0062] A sixth embodiment may include any one of the first through fifth embodiments, including about 0.01 to about 2 weight percent cubic ceria abrasive particles at the point of use.

[0063] A seventh embodiment can include any one of the first through sixth embodiments, wherein the anionic compound includes a water-soluble polyelectrolyte, a polyanion, a polyacid, a polyacrylate, a poly(vinyl acid), an anionic detergent, an alkyl or alkyl ether sulfonates and sulfates, an alkyl or alkyl ether phosphonates and phosphates, and an alkyl or alkyl ether carboxylates.

[0064] An eighth embodiment may include any one of the first to seventh embodiments, wherein the anionic compound is an anionic homopolymer or copolymer and includes at least one monomer unit selected from acrylic acid, methacrylic acid, maleic acid, vinyl sulfonic acid, sulfate, styrene sulfonic acid, and phosphate.

[0065] A ninth embodiment can include any one of the first through eighth embodiments, wherein the anionic compound comprises poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(vinyl sulfate), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(vinyl phosphoric acid), poly(methyl methacrylate-co-methacrylic acid), poly(acrylic acid-co-maleic acid), poly(acrylamide-co-acrylic acid), poly(4-styrenesulfonic acid-co-maleic acid), or a combination thereof.

[0066] A tenth embodiment can include any one of the first through ninth embodiments, wherein the anionic compound is a non-polymeric compound and includes an alkyl or alkylaryl sulfate, an alkyl or alkylaryl sulfonate, an alkyl or alkylaryl phosphate, an alkyl or alkylaryl carboxylate, or a combination thereof.

[0067] An eleventh embodiment may include any one of the first to tenth embodiments, wherein the anionic compound is dodecylbenzenesulfonic acid, ammonium lauryl sulfate, stearic acid, dihexaphosphate, dodecylphosphoric acid, 1-decanesulfonate, derivatives thereof, ammonium or sodium salts thereof, or combinations thereof.

[0068] A twelfth embodiment may include any one of the first to eleventh embodiments, wherein the nonionic compound is a nonionic polymer comprising a water-soluble polyether, a polyether glycol, an alcohol ethoxylate, a polyoxyalkylene alkyl ether, a polyester, a vinyl acrylate, or a combination thereof.

[0069] A thirteenth embodiment may include any one of the first through twelfth embodiments, wherein the nonionic compound is a nonionic homopolymer or copolymer, and includes polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, poly(vinyl phenyl ketone), poly(vinyl pyridine), poly(vinylimidazole), 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, poly(vinyl acetate-co-methyl methacrylate), poly(vinyl pyrrolidone-co-vinyl acetate), poly(ethylene-co-vinyl acetate), and combinations thereof.

[0070] A fourteenth embodiment may include any one of the first through thirteenth embodiments, including about 0.01 weight percent to about 2 weight percent of an anionic or nonionic compound at the point of use.

[0071] A fifteenth embodiment may include any one of the first to fourteenth embodiments, wherein the pH is about 4 to about 6, or about 9 to about 11.

[0072] A sixteenth embodiment may include any one of the first through fifteenth embodiments, comprising about 0.01 weight percent to about 2 weight percent cubic ceria abrasive particles at the point of use, (i) the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size of about 50 to about 500 nm, (ii) the anionic compound comprises poly(acrylic acid), and (iii) the pH of the composition is about 4 to about 6.

[0073] A seventeenth embodiment may include any one of the first through sixteenth embodiments, comprising from about 0.01 weight percent to about 2 weight percent cubic ceria abrasive particles at the point of use; (i) the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size of from about 50 to about 500 nm; (ii) the nonionic compound comprises polyvinylpyrrolidone, poly(vinylpyrrolidone-co-vinyl acetate), or a mixture thereof; and (iii) the pH of the composition is from about 9 to about 11.

[0074] An eighteenth embodiment may include any one of the first through seventeenth embodiments, including about 0.01 weight percent to about 2 weight percent cubic ceria abrasive particles at the point of use; (i) the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size of about 50 to about 500 nm; (ii) the anionic compound comprises poly(methacrylic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), dodecylbenzenesulfonic acid, and mixtures thereof; and (iii) The pH of the composition is about 9 to about 11.

[0075] A nineteenth embodiment includes a method for chemical-mechanical polishing a substrate comprising a silicon oxide dielectric material, the method including (a) providing any one of the first through eighteenth polishing composition embodiments, (b) contacting the substrate with the provided polishing composition, (c) moving the polishing composition relative to the substrate, and (d) ablating the substrate to remove a portion of the silicon oxide dielectric material from the substrate, thereby polishing the substrate.

[0076] A twentieth embodiment may include the nineteenth embodiment, wherein the polishing composition comprises about 0.01 to 2 wt. % cubic ceria abrasive particles at the point of use, the cubic ceria abrasive particles comprising a mixture of cerium oxide and lanthanum oxide and having an average particle size of about 50 to about 500 nm, (ii) the anionic compound comprises poly(acrylic acid), (iii) the pH of the polishing composition is about 4 to about 6, and (iv) during the ablation process in (d), the removal rate of the silicon oxide dielectric material is at least 1000 Å / min.

[0077] A twenty-first embodiment may include the twentieth embodiment, wherein the substrate further comprises at least one of a silicon nitride material and a polysilicon material, and wherein the removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material or the removal rate selectivity of the silicon oxide dielectric material to the polysilicon material is greater than about 10:1 in (d).

[0078] A 22nd embodiment may include the 19th embodiment, wherein (i) the polishing composition comprises about 0.01 to 2 wt. % cubic ceria abrasive particles at the point of use, the cubic ceria abrasive particles comprising a mixture of cerium oxide and lanthanum oxide and having an average particle size of about 50 to about 500 nm, (ii) the nonionic compound comprises polyvinylpyrrolidone, (iii) the pH of the polishing composition is about 9 to about 11, (iv) the substrate further comprises a silicon nitride material, and (v) the removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material is less than about 1:1 in (d).

[0079] A 23rd embodiment may include the 19th embodiment, wherein (i) the polishing composition comprises about 0.01 to 2 wt. % cubic ceria abrasive particles at the point of use, the cubic ceria abrasive particles comprising a mixture of cerium oxide and lanthanum oxide and having an average particle size of about 50 to about 500 nm, (ii) the anionic compound comprises poly(methacrylic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), dodecylbenzenesulfonic acid, and mixtures thereof, (iii) the pH of the composition is about 9 to about 11, and (iv) during the ablation process in (d), the removal rate of the silicon oxide dielectric material is at least 3000 Å / min.

[0080] A twenty-fourth embodiment may include the twenty-third embodiment, wherein the substrate further comprises a silicon nitride material, and the removal rate selectivity of silicon oxide dielectric material to the silicon nitride material is less than about 10:1 in (d).

[0081] A 25th embodiment can include any one of the 19th through 24th embodiments, wherein providing the polishing composition includes providing a polishing concentrate and diluting the polishing concentrate with at least 1 part water to 1 part polishing concentrate. [Example]

[0082] The following examples further illustrate the present invention, but 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 on the Mirra® for 60 seconds at a platen speed of 100 rpm, a head speed of 85 rpm, a downforce of 3 psi, and a slurry flow rate of 150 ml / min. Wafers were polished on a NexPlanar® E6088 pad (available from Cabot Microelectronics Corporation) with in-situ conditioning using a Saesol DS8051 conditioner at 6 lbs downforce.

[0083] Blanket tetraethyl orthosilicate (TEOS), SiN, and polysilicon wafers were polished in the following examples. TEOS wafers were obtained from WRS Materials and contained a 20 kÅ TEOS layer. SiN wafers included both SiN PE and SiN LP wafers. SiN PE was obtained from Advantec and contained a 5 kÅ PE SiN layer. SiN LP wafers were obtained from Novati and contained a 3 kÅ LP SiN layer. Polysilicon wafers were obtained from WRS Materials and contained a 10 kÅ PolySi layer.

[0084] Example 1 A stock cerium oxide dispersion was prepared as follows: A cerium nitrate solution was prepared by combining 13.1 kg of 3 M trivalent cerium(III) nitrate solution, 0.3 kg of 3 M lanthanum nitrate solution, 2.0 kg of 68% nitric acid (HNO) solution, 0.5 kg of deionized water, and cerium(IV) nitrate at a molar ratio of cerium(IV) to cerium (total) of 0.000055. The cerium nitrate solution was then degassed in a 20 L vessel by stirring and bubbling with nitrogen.

[0085] An aqueous ammonia solution was prepared by combining 75 kg of deionized water with 13.1 kg of 25% aqueous ammonia solution (which resulted in a molar ratio of NH4OH in the aqueous ammonia solution to the total amount of cerium and lanthanum in the cerium nitrate solution of 9.0). The aqueous ammonia solution was then degassed in a 100 L jacketed reactor by stirring and bubbling with nitrogen.

[0086] 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 80°C and held at that temperature for 18 hours. The reaction mixture was then allowed to cool and, once cooled, was acidified to pH 2 by the addition of 68% nitric acid.

[0087] The reaction mixture was then filtered and washed with deionized water. The washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm. The final cerium oxide concentration was adjusted to 10 weight percent by adding deionized water. The cubic ceria abrasive particles contained 2.5 mole percent lanthanum oxide and 97.5 mole percent cerium oxide.

[0088] Nitrogen adsorption increases the BET specific surface area to 11.3m 2 The mean particle size was determined to be 102 nm as measured by a Horiba 960 and 140 nm as measured by a Malvern Zetasizer.

[0089] Example 2 Two polishing compositions were tested to evaluate the removal rates of TEOS, SiN-PE, SiN-LP, and PolySi. Each composition contained poly(acrylic acid) (MW approximately 5000) and ceria at a pH of 4.5. Composition 2A contained control ceria (wet process ceria HC60®, commercially available from Rhodia), while Composition 2B contained the cubic ceria described above in Example 1. The use point concentrations are shown in Table 1A. [Table 1A]

[0090] Blanket TEOS, SiN-PE, SiN-LP, and PolySi wafers were polished on a Mirra® tool under the above conditions for 60 seconds. The polishing results are shown in Table 1B. All removal rates (RR) are given in angstroms per minute (Å / min). The selectivities for TEOS:SiN-PE, TEOS:SiN-LP, and TEOS:PolySi are shown in Table 1C. [Table 1B] [Table 1C]

[0091] As is readily apparent from the results shown in Tables 1B and 1C, the TEOS removal rate for Composition 2B (containing the cubic ceria abrasive) was three times that of Composition 2A (containing the control ceria), while the removal rates for silicon nitride and polysilicon were similar. As a result, Composition 2B exhibited approximately three times higher selectivity for TEOS to SiN and TEOS to polysilicon than Composition 2A.

[0092] Example 3 Two polishing compositions were tested to evaluate the removal rates of TEOS, SiN-PE, SiN-LP, and PolySi. Each composition contained poly(methacrylic acid) sodium salt (MW approximately 9500 g / mol) and ceria at a pH of 10. Composition 3A contained the control ceria described above in Example 2, while Composition 3B contained the cubic ceria described above in Example 1. The use point concentrations are shown in Table 2A. [Table 2A]

[0093] Blanket TEOS, SiN-PE, SiN-LP, and PolySi wafers were polished on a Mirra® tool under the above conditions for 60 seconds. The polishing results are shown in Table 2B. All removal rates (RR) are given in angstroms per minute (Å / min). The selectivities for TEOS:SiN-PE, TEOS:SiN-LP, and TEOS:PolySi are shown in Table 2C. [Table 2B] [Table 2C]

[0094] As is readily apparent from the results shown in Tables 2B and 2C, the removal rates of TEOS and SiN for Composition 3B (containing cubic ceria abrasive) were unexpectedly approximately twice that of Composition 3A (containing control ceria), while the removal rates of polysilicon were similar. As a result, Composition 3B exhibited both higher removal rates and a two-fold increase in the selectivity of TEOS to polysilicon compared to Composition 3A.

[0095] Example 4 Two polishing compositions were tested to evaluate the removal rates of TEOS, SiN-PE, SiN-LP, and PolySi. Each composition contained poly(vinyl sulfonic acid) and ceria at a pH of 10. Composition 4A contained the control ceria described above in Example 2, while Composition 4B contained the cubic ceria described above in Example 1. The use point concentrations are shown in Table 3A. [Table 3A]

[0096] Blanket TEOS, SiN-PE, SiN-LP, and PolySi wafers were polished on a Mirra® tool under the above conditions for 60 seconds. The polishing results are shown in Table 3B. All removal rates (RR) are given in angstroms per minute (Å / min). The selectivities for TEOS:SiN-PE, TEOS:SiN-LP, and TEOS:PolySi are shown in Table 3C. [Table 3B] [Table 3C]

[0097] As is readily apparent from the results shown in Tables 3B and 3C, the TEOS and SiN removal rates of Composition 4B (containing cubic ceria abrasive) were significantly higher than those of Composition 4A (containing control ceria) (1.9 times higher for TEOS, about 2.6 times higher for SiN-PE, and about 1.7 times higher for SiN-LP), while the polysilicon removal rates were similar. As a result, Composition 4B unexpectedly exhibited increased removal rates of TEOS and SiN, reduced selectivity of TEOS over SiN-PE, and a 70% increase in selectivity of TEOS over polysilicon, compared to Composition 4A. Furthermore, the composition based on cubic ceria abrasive particles significantly enhanced the SiN-PE removal rate over SiN-LP (150 percent vs. 70 percent).

[0098] Example 5 Two polishing compositions were tested to evaluate the removal rates of TEOS, SiN-PE, SiN-LP, and PolySi. Each composition contained 4-dodecylbenzenesulfonic acid and ceria at a pH of 10. Composition 5A contained the control ceria described in Example 2, while Composition 5B contained the cubic ceria described in Example 1 above. The use point concentrations are shown in Table 2A. [Table 4A]

[0099] Blanket TEOS, SiN-PE, SiN-LP, and PolySi wafers were polished on a Mirra® tool under the above conditions for 60 seconds. The polishing results are shown in Table 4B. All removal rates (RR) are given in angstroms per minute (Å / min). The selectivities for TEOS:SiN-PE, TEOS:SiN-LP, and TEOS:PolySi are shown in Table 4C. [Table 4B] [Table 4C]

[0100] As is readily apparent from the results shown in Tables 4B and 4C, the removal rates of TEOS and SiN for Composition 5B (containing the cubic ceria abrasive) were unexpectedly increased (approximately 2-fold and 1.3-fold, respectively) compared to Composition 5A (containing the control ceria), while the polysilicon removal rate was similar. As a result, Composition 5B unexpectedly exhibited increased removal rates of TEOS and SiN-LP, and a 2-fold increased selectivity of TEOS over polysilicon, compared to Composition 5A. Furthermore, the cubic ceria-based composition unexpectedly significantly increased the removal rate of SiN-LP over SiN-PE (100 percent vs. 25 percent).

[0101] Example 6 Four polishing compositions were tested to evaluate the removal rates of TEOS, SiN-PE, SiN-LP, and PolySi. Each composition contained polyvinylpyrrolidone (PVP) (6A and 6B) or poly(vinylpyrrolidone-co-vinyl acetate) (PVP-co-VA) (6C and 6D) and ceria at a pH of 5. Compositions 6A and 6C contained the control ceria described in Example 2, while compositions 6B and 6D contained the cubic ceria described in Example 1 above. The use point concentrations are shown in Table 5A. [Table 5A]

[0102] Blanket TEOS, SiN-PE, SiN-LP, and PolySi wafers were polished on a Mirra® tool under the above conditions for 60 seconds. The polishing results are shown in Table 5B. All removal rates (RR) are given in angstroms per minute (Å / min). The selectivities for TEOS:SiN-PE, TEOS:SiN-LP, and TEOS:PolySi are shown in Table 5C. [Table 5B] [Table 5C]

[0103] As is readily apparent from the results shown in Tables 5B and 5C, Composition 6D (comprising a cubic ceria abrasive and copolymer poly(vinylpyrrolidone-co-vinyl acetate)) exhibited higher removal rates for TEOS, SiN, and polysilicon compared to Composition 6C (comprising control ceria and the same copolymer). However, Composition 6B (comprising a cubic ceria abrasive and homopolymer polyvinylpyrrolidone) exhibited four times lower TEOS removal rate, a 15% higher removal rate for SiN-PE, and a 25% higher removal rate for SiN-LP compared to Composition 6A (comprising control ceria and the same homopolymer). Composition 6B was surprisingly selective to silicon nitride (2:1 selectivity between SiN-PE and TEOS).

[0104] Example 7 Three compositions were tested to evaluate the effect of lanthanum doping level in cubic ceria abrasive particles on TEOS removal rate. Composition 7A contained 0.28 weight percent of the control ceria described in Example 2. Composition 7B contained 0.28 weight percent of cubic ceria abrasive particles containing 2.5 mole percent lanthanum oxide and was prepared by diluting the stock ceria dispersion described in Example 1 with 34 parts water to 1 part stock ceria dispersion. Composition 7C 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. The pH of each of Compositions 7A-7C was 4.

[0105] A cerium oxide dispersion was prepared as follows: A cerium nitrate solution was prepared by combining 11.5 kg of 3 M trivalent cerium(III) nitrate solution, 1.3 kg of 3 M lanthanum nitrate solution, 1.86 kg of 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) of 0.0000125 (1 / 80,235). The cerium nitrate solution was then degassed in a 20 L vessel by stirring and bubbling with nitrogen.

[0106] An aqueous ammonia solution was prepared by combining 70 kg of deionized water with 14 kg of a 25% aqueous ammonia solution (which resulted in a molar ratio of NH4OH in the aqueous ammonia solution to the total amount of cerium and lanthanum in the cerium nitrate solution of 10). The aqueous ammonia solution was then degassed in a 100 L jacketed reactor by stirring and bubbling with nitrogen.

[0107] 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, once cooled, was acidified to pH 2 by the addition of 68% nitric acid.

[0108] The reaction mixture was then filtered and washed with deionized water. The washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm. The final cerium oxide concentration was adjusted to 10 percent by weight by adding deionized water. The cubic ceria abrasive particles contained 10 mole percent lanthanum oxide and 90 mole percent cerium oxide.

[0109] Nitrogen adsorption increases the BET specific surface area to 8.6m 2 The average particle size was determined to be 142 nm as measured by a Malvern Zetasizer.

[0110] A blanket TEOS wafer was polished on a Mirra® tool for 60 seconds under the above conditions. The polishing results are shown in Table 6. All removal rates (RR) are listed in angstroms per minute (Å / min). [Table 6]

[0111] As is readily apparent from the data presented in Table 6, compositions 7B and 7C exhibited comparable TEOS removal rates that were more than 1.6 times the removal rate of composition 7A.

[0112] Example 8 Three polishing compositions were tested to evaluate the effect of lanthanum doping level in cubic ceria abrasive particles on TEOS removal rate. Compositions 8A and 8B each contained 83.3 wt. ppm picolinic acid, 1000 wt. ppm poly(ethylene glycol) (MW approximately 8000 g / mol), 10.7 wt. ppm Kordek MLX, and 0.4 wt. % ceria abrasive. Composition 8A contained control ceria (Example 2). Composition 8B contained cubic ceria abrasive particles containing 2.5 mol. % lanthanum oxide. Composition 8C contained 58.3 wt. ppm picolinic acid, 700 wt. ppm poly(ethylene glycol) (MW approximately 8000 g / mol), 7.5 wt. ppm Kordek MLX, and 0.28 wt. % cubic ceria abrasive particles containing 10 mol. % lanthanum oxide. The pH of each of Compositions 8A to 8C was 4.

[0113] A blanket TEOS wafer was polished on a Mirra® tool for 60 seconds under the above conditions. The polishing results are shown in Table 7. All removal rates (RR) are given in Angstroms per minute (Å / min). [Table 7]

[0114] As is readily apparent from the results shown in Table 7, the cubic ceria-based compositions (8B and 8C) exhibited similar TEOS removal rates. Furthermore, the cubic ceria compositions exhibited significantly improved TEOS removal rates compared to the control (approximately a 60 percent improvement).

[0115] When used in the context of describing the present invention, "a," "an," "the," and similar referents should be construed to cover both the singular and the plural unless otherwise specified or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., "including, but not limited to") unless otherwise specified. The recitation of ranges of values ​​herein, unless otherwise specified, is merely intended to serve as a shorthand method for referring individually to each separate value falling within that range, and each separate value is incorporated herein as if it were individually set forth herein. All methods described herein can be performed in any suitable order unless otherwise specified herein or clearly contradicted by context. Any and all examples, or example language (e.g., "such as") provided herein are intended merely to better illustrate the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0116] 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 foregoing description. The inventors contemplate that skilled artisans will adopt such variations as necessary, and the inventors intend that the invention may be 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. Furthermore, 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.

[0117] Of course, the disclosure includes numerous embodiments beyond those included in the above examples, including, but not limited to, the aspects recited in the appended claims.

Claims

1. 1. A chemical-mechanical polishing composition comprising: A liquid carrier; cubic abrasive particles dispersed in said liquid carrier; at least one of an anionic compound and a nonionic compound; 1. A chemical-mechanical polishing composition comprising:

2. 10. The composition of claim 1, wherein the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide.

3. 10. The composition of claim 1, wherein the cubic ceria abrasive particles have a molar ratio of lanthanum to lanthanum and cerium of from about 1 to about 15 percent.

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

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

6. 10. The composition of claim 1 comprising from about 0.01 to about 2 weight percent of cubic ceria abrasive particles at the point of use.

7. 10. The composition of claim 1, wherein the anionic compound comprises a water-soluble polyelectrolyte, a polyanion, a polyacid, a polyacrylate, a poly(vinyl acid), an anionic detergent, an alkyl or alkyl ether sulfonates and sulfates, alkyl or alkyl ether phosphonates and phosphates, and an alkyl or alkyl ether carboxylates.

8. 10. The composition of claim 1, wherein the anionic compound is an anionic homopolymer or copolymer and comprises at least one monomer unit selected from acrylic acid, methacrylic acid, maleic acid, vinyl sulfonic acid, sulfate, styrene sulfonic acid, and phosphate.

9. 10. The composition of claim 1, wherein the anionic compound comprises poly(acrylic acid), poly(methacrylic acid), poly(maleic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(vinyl sulfate), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(vinyl phosphoric acid), poly(methyl methacrylate-co-methacrylic acid), poly(acrylic acid-co-maleic acid), poly(acrylamide-co-acrylic acid), poly(4-styrenesulfonic acid-co-maleic acid), or a combination thereof.

10. 10. The composition of claim 1, wherein the anionic compound is a non-polymeric compound and comprises an alkyl or alkylaryl sulfate, an alkyl or alkylaryl sulfonate, an alkyl or alkylaryl phosphate, an alkyl or alkylaryl carboxylate, or a combination thereof.

11. 2. The composition of claim 1, wherein the anionic compound is dodecylbenzenesulfonic acid, ammonium lauryl sulfate, stearic acid, dihexaphosphate, dodecylphosphoric acid, 1-decanesulfonate, derivatives thereof, ammonium or sodium salts thereof, or combinations thereof.

12. 10. The composition of claim 1, wherein the nonionic compound is a nonionic polymer comprising a water-soluble polyether, a polyether glycol, an alcohol ethoxylate, a polyoxyalkylene alkyl ether, a polyester, a vinyl acrylate, or a combination thereof.

13. 13. The composition of claim 12, wherein the nonionic compound is a nonionic homopolymer or copolymer and includes polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, poly(vinyl phenyl ketone), poly(vinyl pyridine), poly(vinylimidazole), 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, poly(vinyl acetate-co-methyl methacrylate), poly(vinyl pyrrolidone-co-vinyl acetate), poly(ethylene-co-vinyl acetate), and combinations thereof.

14. 10. The composition of claim 1, comprising from about 0.01 weight percent to about 2 weight percent of an anionic or nonionic compound at the point of use.

15. 10. The composition of claim 1, wherein the pH ranges from about 4 to about 6, or from about 9 to about 11.

16. comprising about 0.01 weight percent to about 2 weight percent cubic ceria abrasive particles at the point of use; the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size ranging from about 50 to about 500 nm; the anionic compound comprises poly(acrylic acid); and the pH of the composition is in the range of about 4 to about 6; The composition of claim 1.

17. comprising about 0.01 weight percent to about 2 weight percent cubic ceria abrasive particles at the point of use; the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size ranging from about 50 to about 500 nm; the nonionic compound comprises polyvinylpyrrolidone, poly(vinylpyrrolidone-co-vinyl acetate), or a mixture thereof; and the pH of the composition is in the range of about 9 to about 11; The composition of claim 1.

18. comprising about 0.01 weight percent to about 2 weight percent cubic ceria abrasive particles at the point of use; the cubic ceria abrasive particles comprise a mixture of cerium oxide and lanthanum oxide and have an average particle size ranging from about 50 to about 500 nm; the anionic compound comprises poly(methacrylic acid), poly(vinylsulfonic acid), poly(styrenesulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), dodecylbenzenesulfonic acid, and mixtures thereof; and the pH of the composition is in the range of about 9 to about 11; The composition of claim 1.

19. 1. A method for chemical mechanical polishing a substrate comprising a silicon oxide dielectric material, the method comprising: (a) providing (i) a liquid carrier; (ii) cubic abrasive particles dispersed in the liquid carrier; and (iii) at least one of an anionic compound and a nonionic compound; (b) contacting the substrate with the provided polishing composition; (c) moving the polishing composition relative to the substrate; and (d) grinding the substrate to remove a portion of the silicon oxide dielectric material from the substrate, thereby polishing the substrate; 1. A method for chemical mechanical polishing a substrate comprising a silicon oxide dielectric material, comprising:

20. the polishing composition comprises about 0.01 to 2 wt. % cubic ceria abrasive particles at the point of use, the cubic ceria abrasive particles comprising a mixture of cerium oxide and lanthanum oxide and having an average particle size in the range of about 50 to about 500 nm; the anionic compound comprises poly(acrylic acid); the polishing composition has a pH in the range of about 4 to about 6; and During grinding in step (d), the removal rate of the silicon oxide dielectric material is at least 1000 Å / min.

20. The method of claim 19.

21. the substrate further comprises at least one of a silicon nitride material and a polysilicon material; and the removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material or the removal rate selectivity of the silicon oxide dielectric material to the polysilicon material is greater than about 10:1 in step (d); 21. The method of claim 20.

22. the polishing composition comprises about 0.01 to 2 wt. % cubic ceria abrasive particles at the point of use, the cubic ceria abrasive particles comprising a mixture of cerium oxide and lanthanum oxide and having an average particle size in the range of about 50 to about 500 nm; the nonionic compound comprises polyvinylpyrrolidone; the polishing composition has a pH in the range of about 9 to about 11; the substrate further comprises a silicon nitride material; and the removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material is less than about 1:1 in step (d); 20. The method of claim 19.

23. the polishing composition comprises about 0.01 to 2 wt. % cubic ceria abrasive particles at the point of use, the cubic ceria abrasive particles comprising a mixture of cerium oxide and lanthanum oxide and having an average particle size in the range of about 50 to about 500 nm; the anionic compound comprises poly(methacrylic acid), poly(vinyl sulfonic acid), poly(styrene sulfonic acid), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(4-styrenesulfonic acid-co-maleic acid), dodecylbenzenesulfonic acid, and mixtures thereof; the pH of the composition is in the range of about 9 to about 11; and During grinding in step (d), the removal rate of the silicon oxide dielectric material is at least 3000 Å / min.

20. The method of claim 19.

24. the substrate further comprises a silicon nitride material; the removal rate selectivity of the silicon oxide dielectric material to the silicon nitride material is less than about 10:1 in step (d); 24. The method of claim 23.

25. 20. The method of claim 19, wherein providing the polishing composition comprises: (ai) providing a polishing concentrate; and (aii) diluting the polishing concentrate with at least 1 part water to 1 part polishing concentrate.

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