Compositions and methods for silicon dioxide and carbon-doped silicon dioxide CMP

Abstract

A chemical-mechanical polishing composition for polishing a substrate having a silicon-oxygen material includes a liquid carrier, cubic ceria abrasive particles dispersed in the liquid carrier, and an organic diacid.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the interests of U.S. Provisional Patent Application No. 62 / 924,332, titled "Composition and Method for Silicon Oxide and Carbon Doped Silicon Oxide CMP," filed on 22 October 2019. [Background technology]

[0002] Chemical mechanical polishing (CMP) is an important enabling technique in the fabrication of integrated circuits (ICs) and microelectromechanical systems (MEMS). CMP compositions and methods for polishing (or planarizing) the surface of substrates (e.g., wafers) 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 defect rate 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 abrasive compositions are commonly used in high-performance dielectric applications, including, for example, shallow trench isolation applications. While the use of ceria abrasives is well known, there is still a need for improved ceria abrasive CMP compositions. In particular, there is still a need for CMP compositions that provide improved removal rates and improved planarization (e.g., reduced corrosion and dishing). Furthermore, there is still a need for compositions that provide removal rate selectivity between one silicon-containing substrate and another (e.g., silicon oxide vs. silicon nitride selectivity or silicon oxide vs. polysilicon selectivity). [Overview of the project]

[0004] Disclosed are chemical mechanical polishing compositions for polishing substrates having silicon-oxygen materials (e.g., silicon oxide) and / or carbon-doped silicon-oxygen materials. In one embodiment, the polishing composition comprises, consists of, or is essentially composed of, a liquid carrier, cubic ceria abrasive particles dispersed in the liquid carrier, and an organic diacitor.

[0005] For a more complete understanding of the disclosed subject matter and its benefits, please refer here to the following detailed description in conjunction with the attached figures. [Brief explanation of the drawing]

[0006] [Figure 1] This image shows a transmission electron microscope (TEM) photograph of a cubic ceria abrasive sample exhibiting ceria abrasive particles with square faces. [Figure 2] This image shows a transmission electron microscope (TEM) photograph of a cubic ceria abrasive sample exhibiting ceria abrasive particles with square faces. [Figure 3] This image shows a scanning electron microscope (SEM) photograph of a cubic ceria abrasive sample exhibiting ceria abrasive particles with square faces. [Modes for carrying out the invention]

[0007] Disclosed are chemical mechanical polishing compositions for polishing substrates having silicon-oxygen materials (e.g., silicon oxide) and / or carbon-doped silicon-oxygen materials. The polishing composition comprises, consists of, or is essentially composed of, a liquid carrier, cubic ceria abrasive particles dispersed in the liquid carrier, and an organic diacid. In one embodiment, the organic diacid comprises a linear saturated dicarboxylic acid or polyethylene glycol diacid.

[0008] The disclosed polishing compositions and corresponding methods (CMP method) may offer significant and unexpected advantages. For example, the disclosed compositions may provide a significantly improved silicon dioxide removal rate, thereby improving throughput and saving time and money. The disclosed compositions may further provide a reduced polysilicon removal rate and significantly improved silicon dioxide-to-polysilicon selectivity. The disclosed compositions may further provide improved dishing and corrosion across a wide range of pattern features and densities. Certain embodiments may further provide a significantly improved removal rate when polishing carbon-doped silicon dioxide materials.

[0009] The abrasive composition contains abrasive particles, including cubic cerium oxide abrasive particles suspended in a liquid carrier. The term "cubic" implies that the ceria abrasive particles are in the form or shape of a cube, i.e., substantially cubic. In other words, cubic ceria abrasive particles are cubic in form or property. However, it will be understood that the edge dimensions, corners, and corner angles do not need to be exactly or precisely cubic. For example, cubic abrasive particles may have slightly rounded or missing corners, slightly rounded edges, edge dimensions that are not exactly equal to each other, corner angles that are not exactly 90 degrees, and / or other minor irregularities, while still retaining a basic cubic form. Those skilled in the art will readily recognize (e.g., via a scanning electron microscope or transmission electron microscope) that cubic ceria abrasive particles are cubic in form to a generally accepted tolerance with respect to particle growth and deaggregation.

[0010] Figures 1, 2, and 3 show example cubic ceria abrasive particles. These transmission electron microscope (TEM) and scanning electron microscope (SEM) images show ceria abrasive particles having square faces. For example, in these images, each shown particle face contains four edges of substantially the same length (e.g., within 20 percent of each other or even 10 percent of each other). Furthermore, these edges intersect at the corners at an angle of approximately 90 degrees (e.g., within the range of about 80–100 degrees or about 85–95 degrees). Those skilled in the art will readily see in the TEM and SEM images that a significantly large majority of the shown abrasive particles 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. Furthermore, it should be understood that the term "cubic" is intended to describe particles that are essentially generally cubic, as described above and shown in Figures 1, 2, and 3, rather than ceria abrasive particles that are precisely cubic.

[0011] When used herein, a chemical mechanical abrasive composition containing cubic ceria abrasives is one in which at least 25 number percent of the abrasive particles are essentially cubic (i.e., 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 readily evaluated and counted using TEM or SEM imaging at magnifications ranging, for example, from about 10,000x to about 500,000x. The SEM or TEM image shows abrasive particles having a face with four sides of similar length (e.g., within 20 percent of each other as described above). Such an image also shows that adjacent sides are substantially 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 performed on a large number of randomly selected particles (i.e., more than 200) so that the percentage of particles with square faces can be determined by performing statistical analysis. The particles being held must be such that these images are clearly visible in the photograph. Some of the particles may show some defects on their surfaces and / or at one or more of their corners, but may still be counted as cubic.

[0012] The cubic ceria abrasive particles may be substantially pure ceria abrasive particles (within the usual acceptable range for impurities) or doped ceria abrasive particles. The doped ceria abrasive particles may contain interstitial dopants (dopants that occupy spaces within the lattice that are not normally occupied) or substitutional dopants (dopants that occupy spaces within the lattice that are normally occupied by cerium or oxygen atoms). Such dopants may contain substantially 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 one particularly preferred embodiment, the cubic ceria abrasive particles comprise a mixed oxide of cerium and lanthanum. The mixed oxide abrasive particles may have a La-to-(La+Ce) molar ratio in the range of about 0.01 to about 0.15, for example, 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 the 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. The remaining 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 mol percent of lanthanum oxide and about 97.5 mol percent of 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 other such embodiment, the cubic ceria abrasive particles contain about 10 mol percent of lanthanum oxide and about 90 mol percent of 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 symmetric X-ray diffraction pattern with a peak between about 27 and about 29 degrees, which is shifted to a lower angle than pure cerium oxide. Solid solutions can be obtained when the temperature of the aging substep (described later) exceeds approximately 60°C (333K). As used herein, the term “solid solution” means that the X-ray diffraction shows only the pattern of the cerium oxide crystal structure, with or without shifts in individual peaks, but without any further peaks that may suggest the presence of other phases.

[0015] Cubic ceria abrasive particles may be optionally characterized by their specific surface area, which is determined in the powder by nitrogen adsorption using the Brunauer-Emmett-Teller (BET) method. This method is disclosed in ASTM D3663-03 (re-approved in 2015). The abrasive particles are approximately 3 to 14 m². 2 / g (for example, approximately 7 to approximately 13m) 2 / g or approximately 8-12m 2 It may have a specific surface area within the range of ( / g).

[0016] Cubic ceria abrasive particles may be optionally characterized by their average particle size and / or particle size distribution. The abrasive particles may have an average particle size in the range of approximately 50 nm to approximately 1000 nm (e.g., approximately 80 nm to approximately 500 nm, approximately 80 nm to approximately 250 nm, approximately 100 nm to approximately 250 nm, or approximately 150 nm to approximately 250 nm). Alternatively, the average particle size may be greater than approximately 50 nm (e.g., greater than approximately 80 nm or greater than approximately 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 may significantly undercount smaller particles when performed in the presence of relatively larger particles. In the cubic ceria abrasive particles disclosed herein, DLS technology tends to undercount particles smaller than approximately 40 nm. It will be understood that the disclosed embodiments may contain a considerable number of very 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 technology may optionally be used to characterize the particle size distribution. Those skilled in the art will readily recognize that laser diffraction technology also tends to undercount small particles (e.g., less than 40 nm in the disclosed embodiments). Laser diffraction measurements may be made using, for example, a Horiba LA-960 using a relative refractive index of 1.7. From the distribution obtained by laser diffraction measurement, various parameters can be obtained, including, for example, D10, D50, D90, D99, and the dispersion index (defined below). Based on the laser diffraction measurement, the abrasive particles may include a median diameter (D50) within the range of about 100 nm to about 700 nm (e.g., about 100 nm to about 200 nm). For example, D50 may be within 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 may optionally have a D10 within 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 will be understood that D10 represents the particle size obtained by laser diffraction where 10% of the particles have a diameter less than D10.

[0019] The cubic ceria abrasive particles may optionally have a D90 within 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 obtained by laser diffraction where 90% of the particles have a diameter less than D90. The abrasive particles that have undergone mechanical deaggregation may have a D90 less than about 300 nm.

[0020] The cubic ceria abrasive particles may 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 abrasive particles that have undergone mechanical deaggregation may have a dispersion index of less than about 0.30. Also, D90 / D50 may be within the range of about 1.3 to about 2 for the particles that have undergone mechanical deaggregation.

[0021] The cubic ceria abrasive particles may optionally have a D99 within 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 nm to about 1200 nm, about 200 nm 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 abrasive particles that have undergone mechanical deaggregation 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 obtained by laser diffraction where 99% of the particles have a diameter less than D99.

[0022] The abrasive particles may be prepared using substantially 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 manufacturing the particles. In certain embodiments, the cubic ceria abrasive particles may be prepared by precipitating cerium nitrate (and optionally other nitrates when doped ceria abrasive is prepared). The precipitated material may then be grown in a particular temperature and pressure regime to promote the growth of cubic ceria abrasive particles. These particles may then be cleaned and deaggregated. A dispersion of the 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 cerium lanthanum oxide abrasive particles can be prepared by precipitating cerium nitrate and lanthanum nitrate. One such preparation method includes the following steps: (i) Mix the aqueous cerium nitrate solution and the aqueous base under an inert atmosphere. (ii) Heat the mixture obtained in an inert atmosphere (i). (iii) The heat-treated mixture obtained in (ii) is optionally acidified. (iv) Wash the solid material obtained in (ii) or (iii) with water. The solid material obtained in (v)(iv) is mechanically processed to deaggregate 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 Including Ce IV The molar ratio to total Ce may be characterized by being between approximately 1 / (500,000) and approximately 1 / (4,000). In one example embodiment, the molar ratio may be between approximately 1 / (100,000) and approximately 1 / (90,000). It is generally advantageous to use salts and components of high purity, for example, having a purity of at least 99.5 weight percent or even 99.9 weight percent.

[0025] Step (i) comprises mixing / reacting an aqueous solution of cerium nitrate with an aqueous base. Hydroxide-type bases, such as alkali metal or alkaline earth metal oxides and aqueous ammonia, may be advantageous. Secondary, tertiary, or quaternary amines may be used. The aqueous solution of the base may be pre-degassed (deoxygenated) by bubbling with an inert gas. The mixing may be carried out by introducing the aqueous solution of cerium nitrate into the aqueous base, which is advantageously carried out in a closed or semi-closed reactor under an inert atmosphere, for example, with an inert gas (e.g., nitrogen or argon). The 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 between about 5°C (278K) and about 50°C (323K), for example, between about 20°C (293K) and 25°C (298K).

[0026] Step (ii) includes 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 include heating the mixture to a temperature in the range of about 75°C (348K) to about 95°C (368K), for example, in the range of about 85°C (358K) to about 90°C (363K). The aging substep may include maintaining (keeping) the mixture at the above 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 in an inert atmosphere and under 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 to a pH of, for example, 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 residual nitrates in the final dispersion to obtain 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 as 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. The mechanical treatment may include, for example, double-jet treatment or ultrasonic deagglomeration, which typically results in a narrow particle size distribution and a reduction in the number of large aggregated particles.

[0030] After step (iv) or (v), the solid material may be dried to obtain cerium 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 cerium particles in a 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, e.g., propyl alcohol, ethanol, 1-propanol, methanol, 1-hexanol; ketones, e.g., acetone, diacetone alcohol, methyl ethyl ketone; and esters, e.g., ethyl formate, propyl formate, ethyl acetate, methyl acetate, methyl lactate, butyl lactate, ethyl lactate. The ratio of water to the organic liquid may be between 80 and 20 parts by weight, and between 99 and 1 part by weight. The dispersion may also contain about 1% to about 40% by weight, for example, about 10% to about 35% by weight of cerium particles. The dispersion may have a conductivity of less than approximately 300 μS / cm, for example, less than approximately 150, more specifically less than 150 μS / cm, or less than approximately 100 μS / cm.

[0031] The abrasive composition may contain substantially any preferred amount of cubic ceria abrasive particles. For example, the abrasive 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 time of use. The abrasive composition may contain about 5 weight percent or less (e.g., about 2 weight percent or less, about 1.5 weight percent or less, about 1 weight percent or less, or about 0.5 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 abrasive composition at concentrations bounded by any two of the above endpoints. For example, the concentration of cubic ceria abrasive particles in the abrasive composition may be in the range of about 0.001% to about 5% by weight at the time of use (e.g., about 0.01% to about 1% by weight, about 0.02% to about 1% by weight, or about 0.05% to about 0.5% by weight).

[0032] Aqueous liquid carriers are used to facilitate the application of the abrasive and any optional chemical additives to the surface of a substrate to be polished (e.g., planarized). By aqueous, the liquid carrier is intended to consist of at least 50% by weight of water (e.g., deionized water). The liquid carrier may also contain 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 is essentially or derived from water, more preferably from deionized water.

[0033] The abrasive composition is generally acidic, weakly acidic, or neutral, having a pH in the range of about 2 to about 8. For example, the abrasive composition may have a pH in the range of about 2 to about 7. In one embodiment, the abrasive composition is acidic or weakly acidic, having a pH in the range of about 3 to about 6 (e.g., about 3 to about 5). For example, in one such weakly acidic embodiment, the pH may be about 4.

[0034] The abrasive composition further comprises an organic diacid. As used herein, the term organic diacid refers to an organic compound (carbon-containing compound) having two acid groups. For example, an organic diacid may be a carboxylic acid having two carboxyl groups (COOH). Such a diacid may also be referred to as a dicarboxylic acid. The organic diacid may comprise substantially any preferred organic diacid, including, for example, linear saturated dicarboxylic acids, unsaturated dicarboxylic acids, substituted dicarboxylic acids, aromatic dicarboxylic acids, or combinations thereof.

[0035] Linear saturated dicarboxylic acids have the general formula HO2C(CH2) n It has CO2H. Linear means that the diacid is intended to be an unbranched, linear acid. Saturated means that all carbon-carbon bonds are single bonds (i.e., there are no double or triple carbon-carbon bonds). The polishing composition may contain substantially any preferred water-soluble linear saturated dicarboxylic acid (i.e., a linear saturated dicarboxylic acid containing about 3 to about 10 carbon atoms) where n is in the range of 1 to 8. Examples of such linear saturated dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or combinations thereof. Preferred linear saturated dicarboxylic acids include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or combinations thereof (where n is 3 to 8 such that the compound has about 5 to about 10 carbon atoms). Most preferred linear saturated dicarboxylic acids include pimelic acid, suberic acid, azelaic acid, sebacic acid, or combinations thereof (where n is 5 to 8 such that the compound has about 7 to about 10 carbon atoms). For example, in one most preferred embodiment, the polishing composition may contain suberic acid.

[0036] An unsaturated dicarboxylic acid is a dicarboxylic acid containing at least one carbon-carbon double bond or carbon-carbon triple bond. The polishing composition may contain substantially any preferred unsaturated dicarboxylic acid, including, for example, monounsaturated, diunsaturated, or branched dicarboxylic acids. Examples of monounsaturated dicarboxylic acids include maleic acid, fumaric acid, and glutaconic acid. Examples of diunsaturated dicarboxylic acids include muconic acid isomers. Examples of branched dicarboxylic acids include citraconic acid, mesaconic acid, and itaconic acid.

[0037] Substituted dicarboxylic acids include dicarboxylic acids with internal heteroatomic substitutions, including OH, NH2, O, Cl, alkanes, alkynes, or other side groups, and / or N, O, S, or other heteroatoms, as well as combinations thereof. The polishing composition may contain substantially any preferred substituted dicarboxylic acid, including, for example, malic acid, tartaric acid, aspartic acid, diglycolic acid, ketoglutaric acid, glutamic acid, glutathione, 1,3-acetone dicarboxylic acid, 1,3-adamantanedicarboxylic acid, bis(carboxymethyl)trithiocarbonate, chlorosuccinic acid, butylmalonic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, cyclohexylsuccinic acid, trans-1,2-cyclopentanedicarboxylic acid, dibromomaleic acid, 2,3-dibromosuccinic acid, dimethylmalonic acid, ethylmalonic acid, iminodiacetic acid, mercaptosuccinic acid, 2-sulfobutanediic acid, and 3-thiophenmalonic acid.

[0038] Aromatic dicarboxylic acids are dicarboxylic acids containing a carbocyclic ring (for example, a benzene ring with six carbon atoms). The polishing composition may contain substantially any preferred aromatic dicarboxylic acid, including, for example, phthalate isomers, diphenic acid, naphthalenedicarboxylic acid, phenylenedipropionic acid, and 2,2'-bipyridine-4,4'-dicarboxylic acid.

[0039] One skilled in the art will readily recognize that the categories of organic diacids described above overlap such that some diacid compounds fall into two or more of the above categories (e.g., substituted and aromatic). The polishing composition may include such “multi-category” diacids including, for example, 5-tert-butylisophthalic acid, 2,2'-iminodibenzoic acid, 6-methylpyridine-2,3-dicarboxylic acid, 4,4'-oxybis(benzoic acid), and 3-thiophenemalonic acid.

[0040] In the diacid compounds and categories listed above, it will be further understood that one or more of the carboxyl groups may be substituted by another type of acid group including, for example, a sulfonic acid group or a phosphonic acid group. For example, the organic diacid may include carboxyl-PEG2-sulfonic acid and / or carboxyl-PEG2-phosphonic acid.

[0041] It will be still further understood that the organic diacid compound(s) may be used in any available form, e.g., the conjugate acid or base, and that the salt form may be used in place of (or in addition to) the acid(s) listed above.

[0042] The organic diacid may alternatively and / or additionally include polyethylene glycol diacid (PEG diacid). PEG diacid has the general formula: HO2CCH2[OC2H4] n CH2CO2H. PEG diacid may have a substantially any suitable average molecular weight within the range of, for example, about 100 g / mol to about 100,000 g / mol (e.g., about 100 g / mol to about 10,000 g / mol, or about 100 g / mol to about 4000 g / mol). In one preferred embodiment, PEG diacid has a molecular weight of about 600 g / mol.

[0043] The abrasive composition may contain substantially any preferred amount of organic diacid. For example, the abrasive composition may contain at least about 0.1 mmol (mM) of organic diacid per liter at the time of use (e.g., about 0.2 mM or more, about 0.3 mM or more, about 0.5 mM or more, about 0.8 mM or more, or about 1 mM or more). The abrasive composition may contain at least about 20 mM of organic diacid at the time of use (e.g., about 15 mM or less, about 10 mM or less, about 8 mM or less, about 5 mM or less, or about 3 mM or less). It will be understood that the organic diacid may be present in the abrasive composition at concentrations bounded by any two of the above endpoints. For example, the concentration of the organic diacid in the abrasive composition may be in the range of approximately 0.1 mM to approximately 20 mM at the time of use (for example, approximately 0.1 mM to approximately 15 mM, approximately 0.2 mM to approximately 10 mM, approximately 0.3 mM to approximately 8 mM, approximately 0.5 mM to approximately 5 mM, or approximately 1 mM to approximately 5 mM).

[0044] The abrasive composition may optionally further include one or more additional components, for example, various chemical additives. Such additives may associate (for example, via electrostatic interactions and / or hydrogen bonding) with the surface of cubic ceria abrasive particles and / or the surface of the polished substrate. The chemical additives may be, for example, dispersants, rheological agents, polishing rate accelerators, polishing rate inhibitors, or selectivity enhancers (to improve the removal rate ratio of one material to another). Such chemical additives may include, for example, cationic surfactants, anionic surfactants, net neutral surfactants, cationic polymers, anionic polymers, and / or nonionic polymers. It will be understood that the disclosed embodiments are not limited to the use of additives in these cases.

[0045] Certain embodiments, particularly those intended for polishing carbon-doped silicon oxide layers, may further include a polishing rate accelerator. Suitable polishing rate accelerators may include, for example, carboxylic acid compounds that activate the substrate. Examples of rate enhancers include picolinic acid, nicotinic acid, quinaldic acid, isonicotinic acid, acetic acid, and 4-hydroxybenzoic acid. In one advantageous embodiment described below, the polishing rate accelerator includes picolinic acid.

[0046] The disclosed polishing compositions may further contain, for example, unsaturated carboxylate additives to inhibit silicon nitride removal. Suitable unsaturated carboxylates include, for example, acrylic acid, 2-butenoic acid (crotonic acid), 2-pentenoic acid, trans-2-hexenoic acid, trans-3-hexenoic acid, 2-hexic acid, 2,4-hexadienoic acid, potassium sorbate, trans-2-methyl-2-butenoic acid, 3,3-dimethylacrylic acid, or combinations thereof, including their stereoisomers. Crotonic acid is included in one example embodiment described below.

[0047] Certain embodiments of the disclosed polishing compositions may be used to polish carbon-doped (e.g., highly carbon-doped) silicon oxide layers. One advantageous embodiment comprises cubic ceria particles, PEG-3 acid, and picolinic acid. The composition may further optionally contain an unsaturated carbone monoacid, such as crotonic acid.

[0048] The abrasive composition may optionally further contain a biocide. The biocide may be substantially any preferred biocide, for example, an isothiazolinone biocide, such as methylisothiazolinone or benzisothiazolon. The amount of biocide in the abrasive composition at the time of use is typically in the range of about 1 ppm by weight to about 100 ppm by weight, for example, about 5 ppm by weight to about 75 ppm by weight.

[0049] Abrasive compositions may be prepared using any preferred technique, many of which are known to those skilled in the art. Abrasive compositions may be prepared in batch or continuous processes. Generally, abrasive compositions may be prepared by combining their components in any order. The term “component,” as used herein, includes individual components (e.g., abrasive particles, organic dio acids, and any optional additives). For example, organic dio acids may be added to an aqueous carrier (e.g., water) at a desired concentration. The pH may then be adjusted (optionally), and cubic ceria abrasives may be added at a desired concentration(s) to obtain the abrasive composition. Abrasive compositions may be prepared before use by adding one or more components to the abrasive composition immediately before use (e.g., within about 1 minute, or about 1 hour, or about 1 or 7 days before use). Abrasive compositions may also be prepared by mixing the components on the surface of a substrate during the abrasive operation (e.g., in an abrasive pad).

[0050] In certain embodiments, the polishing composition may be provided as a "two-pack" system. For example, the first pack may contain cubic ceria abrasive and other optional components, and the second pack may contain an organic diacid and yet other optional components. The first and second packs may be transported separately and combined on the polishing pad before polishing (e.g., within one hour or one day of polishing) or during the CMP operation.

[0051] The abrasive 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 embodiments, the abrasive composition concentrate may contain cubic ceria abrasive particles, organic diacitors, and other optional additives in such amounts that, when the concentrate is diluted with an appropriate amount of water, each component of the abrasive composition is present in the abrasive composition in an amount within the appropriate range listed above for each component. For example, cubic ceria abrasive particles, organic diacitors, and other optional additives may each be present in the abrasive composition at approximately three times (e.g., approximately four times, five times, six times, seven times, eight times, ten times, fifteen times, twenty times, or twenty-five times) the use-time concentrations listed above for each component, and as a result, when the concentrate is diluted with an equal volume of water (e.g., two equal volumes of water, three equal volumes of water, four equal volumes of water, five equal volumes of water, six equal volumes of water, seven equal volumes of water, nine equal volumes of water, fourteen equal volumes of water, nineteen equal volumes of water, or twenty-four equal volumes of water), each component will be present in the abrasive composition at amounts within the ranges described above for each component.

[0052] In embodiments in which the abrasive composition is provided as a two-pack system, one or both packs may be provided as concentrates requiring 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 about three times (e.g., about five times, about eight times, about ten times, about fifteen times, or about twenty times) above the use-time concentrations listed above. The concentrated first pack may be mixed with a suitable amount of water before being combined with the second pack. Similarly, the second pack may be provided as a concentrate containing an organic diacid at a concentration exceeding about three times (e.g., about five times, about eight times, about ten times, about fifteen times, or about twenty times) above the use-time concentrations listed above. In such embodiments, the concentrated second pack may be mixed with a suitable amount of water before being combined 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.

[0053] The polishing method of the present invention is particularly suitable for use in conjunction with a chemical mechanical polishing (CMP) apparatus, including, for example, a platen and pad to which are attached. As is known to those skilled in the art, polishing of a substrate is performed 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 move relative to each other to wear away at least a portion of the substrate. The method of the present invention includes providing the above-mentioned composition of the present invention, bringing a substrate (e.g., a wafer) into contact with the composition of the present invention, moving the polishing composition relative to the substrate, and wearing down the substrate to remove at least a portion of one layer from the substrate, thereby polishing the substrate.

[0054] The substrate generally includes a silicon oxide-containing dielectric layer. For example, a silicon oxide-containing dielectric material or silicon oxide-based dielectric layer may contain, consist of, or essentially consist of one or more of the following: tetraethoxysilane (TEOS), high-density plasma (HDP) oxide, phosphate silicate glass (PSG), boric phosphate silicate glass (BPSG), high-aspect-ratio process (HARP) oxide, spin-on dielectric (SOD) oxide (sometimes referred to as spin-on glass), chemical vapor deposition (CVD) oxide, plasma-enhanced tetraethyl orthosilicate (PETEOS), thermal oxide, or undoped silicate glass.

[0055] The polishing composition preferably exhibits a high removal rate when polishing a substrate containing 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 preferably exhibits a silicon oxide removal rate of about 1000 Å (100 nm) / min or more (e.g., about 2000 Å (200 nm) / min or more, about 2,500 Å (250 nm) / min or more, about 3,000 Å (300 nm) / min or more, about 3,500 Å (350 nm) / min or more, about 4000 Å (400 nm) / min or more, about 4500 Å (450 nm) / min or more, or about 5000 Å (500 nm) / min or more).

[0056] In certain embodiments, the substrate comprises polysilicon in combination with silicon oxide and / or silicon nitride. The polysilicon may be any preferred polysilicon, many of which are known in the art. The polysilicon may have any preferred phase, which may be amorphous, crystalline, or a combination thereof.

[0057] The polishing composition preferably exhibits a low removal rate when polishing a substrate containing polysilicon. For example, when polishing a silicon wafer containing a polysilicon layer, the polishing composition preferably exhibits a polysilicon removal rate of less than about 500 / min (e.g., less than about 200 / min, less than about 150 / min, less than about 100 / min, less than about 75 / min, less than about 50 / min, or less than about 25 / min).

[0058] In certain embodiments, the polishing composition may be advantageously used in stop-on-poly (SOP) applications, such as NAND flash applications. “Stop-on-poly” is intended to result in the polishing composition exhibiting a relatively low polysilicon removal rate and a relatively high silicon dioxide removal rate. In other words, the polishing composition exhibits high silicon dioxide-to-polysilicon removal rate selectivity. In example embodiments, the polishing composition may exhibit a silicon dioxide-to-polysilicon selectivity of at least 40-1 (e.g., at least 50-1, at least 60-1, at least 80-1, at least 100-1, or even at least 150-1).

[0059] The polishing compositions and methods preferably exhibit low dishing and corrosion when polishing substrates having a patterned silicon oxide layer. For example, when polishing a patterned wafer containing silicon oxide material filled on a polysilicon trench, the polishing compositions preferably exhibit corrosion 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 preferably achieve such corrosion 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 percent to 90 percent.

[0060] The disclosed polishing compositions may be further used to polish carbon-doped silicon oxide films (or substrates), for example, highly carbon-doped silicon oxide films (where the highly doped material is intended to contain 50 mole percent or more of carbon). In such applications, the polishing compositions preferably exhibit a high removal rate when polishing carbon-doped silicon oxide materials. For example, when polishing a silicon wafer containing such material, the polishing compositions may exhibit a silicon oxide removal rate of about 1,000 Å (100 nm) / min or more (e.g., about 1,500 Å (150 nm) / min or more, about 2,000 Å (200 nm) / min or more, about 2,500 Å (250 nm) / min or more, or about 3,000 Å (300 nm) / min or more). Achieving a high removal rate in carbon-doped silicon oxide materials (especially highly carbon-doped silicon oxide materials) is due to partial calendering caused by the hydrophobicity of the surface. Certain disclosed embodiments, including cubic ceria particles, may be able to achieve a high carbon-doped silicon oxide material removal rate without the use of a wetting agent in the abrasive composition.

[0061] This disclosure will be understood to include many embodiments. These embodiments include, but are not limited to, the following embodiments.

[0062] In the first embodiment, the chemical mechanical polishing composition comprises a liquid carrier; cubic ceria abrasive particles dispersed in the liquid carrier; and an organic diacid.

[0063] The second embodiment may include the first embodiment, wherein the cubic ceria abrasive particles contain a mixture of cerium oxide and lanthanum oxide.

[0064] The third embodiment may include either the first or second embodiment, wherein the cubic ceria abrasive particles have a lanthanum to lanthanum + cerium molar ratio in the range of about 1 to about 15 percent.

[0065] In the fourth embodiment, 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 within the range of / g.

[0066] The 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.

[0067] The sixth embodiment may include any one of the first to fifth embodiments, which contains cubic ceria abrasive particles in an amount of about 0.01 to about 1 weight percent.

[0068] The seventh embodiment may include any one of the first to sixth embodiments, wherein the diacid is a linear saturated dicarboxylic acid, an unsaturated dicarboxylic acid, a substituted dicarboxylic acid, or an aromatic dicarboxylic acid.

[0069] The eighth embodiment may include any one of the first to seventh embodiments, wherein the diacid comprises a linear saturated dicarboxylic acid.

[0070] The ninth embodiment may include any one of the first to eighth embodiments, wherein the diacid includes glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or a combination thereof.

[0071] The tenth embodiment may include any one of the first to ninth embodiments, wherein the diacid includes pimelic acid, suberic acid, azelaic acid, sebacic acid, or a combination thereof.

[0072] The 11th embodiment may include any one of the 1st to 10th embodiments, wherein the diacid is suberic acid.

[0073] The twelfth embodiment may include any one of the first to sixth embodiments, wherein the diacid contains polyethylene glycol diacid.

[0074] The 13th embodiment may include the 12th embodiment, wherein the polyethylene glycol diacid has a molecular weight in the range of about 100 to about 1200 g / mol.

[0075] The 14th embodiment may include any one of the 1st to 13th embodiments having a pH in the range of about 3 to about 5.

[0076] The 15th embodiment may include any one of the 1st to 14th embodiments, which contains at least 1 mM of an organic diacid at the time of use.

[0077] The 16th embodiment comprises, at the time of use, about 0.01 to about 1 weight percent of cubic ceria abrasive particles: (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 organic diacid is suberic acid, polyethylene glycol diacid, or a mixture thereof; and (iii) the composition has a pH in the range of about 3 to about 5, comprising any one of the 1st to 15th embodiments.

[0078] The 17th embodiment may include the 16th embodiment, wherein the organic diacid is polyethylene glycol diacid, and the composition further comprises picolinic acid.

[0079] The 18th embodiment may further include crotonic acid, and may include the 17th embodiment.

[0080] The 19th embodiment may include any one of the 1st to 18th embodiments, further comprising at least one of a cationic surfactant, anionic surfactant, net neutral surfactant, cationic polymer, anionic polymer, nonionic polymer, and biocide.

[0081] The 20th embodiment includes a method for chemically mechanically polishing a substrate containing a silicon oxide dielectric material. The method includes: (a) providing a polishing composition comprising any one of the 1st to 19th embodiments; (b) bringing a substrate into contact with the provided polishing composition; (c) moving the polishing composition relative to the substrate; and (d) polishing the substrate by abrading it to remove a portion of the silicon oxide dielectric material from the substrate.

[0082] The 21st embodiment may include the 20th embodiment, wherein the substrate further comprises a polysilicon material, and the removal rate selectivity between the silicon oxide material and the polysilicon material is greater than about 50:1 in (d).

[0083] The 22nd embodiment may include the 20th embodiment, wherein the silicon oxide dielectric material is a carbon-doped silicon oxide material, and the removal rate of the carbon-doped silicon oxide material exceeds approximately 1000 Å (100 nm) / min in (d).

[0084] The 23rd embodiment may include the 22nd embodiment, wherein the carbon-doped silicon oxide material contains more than 50 mole percent of carbon.

[0085] The 24th embodiment may include any one of the 20th to 23rd embodiments, wherein the diacid contains polyethylene glycol diacid.

[0086] The 25th embodiment may include the 24th embodiment, wherein the abrasive composition further comprises at least one of picolinic acid and crotonic acid.

[0087] The 26th embodiment may include any one of the 20th to 25th embodiments, wherein providing any one of the 1st to 19th embodiments above includes (ai) providing an abrasive concentrate, and (aii) obtaining an abrasive composition by diluting the abrasive concentrate with at least some water to make it part of the abrasive concentrate.

[0088] The 27th embodiment may include one of the 20th to 26th embodiments, wherein providing any one of the 1st to 19th embodiments above includes (ai) providing a first pack containing cubic ceria abrasive particles and a second pack containing diacitor, and (aii) combining the first and second packs to obtain an abrasive composition.

[0089] The 28th embodiment may include the 27th embodiment, wherein at least one of the first and second packs is diluted with water before being combined in (aii).

[0090] The following examples further illustrate the invention, but should not be construed as limiting its scope. Various substrates were polished using the Applied Materials Mirra® polishing tool (available from Applied Materials, Inc.). Blanket wafers were polished in the Mirra® for 60 seconds at a platen speed of 100 rpm, a head speed of 85 rpm, a downward force of 3 psi (20684.28 Pa), and a slurry flow rate of 150 ml / min. The above wafers were polished in situ conditioning using a Saesol DS8051 conditioner with a downward force of 6 pounds (2.7126 kg) on ​​a NexPlanar® E6088 pad (Cabot Microelectronics Corporation).

[0091] Blanket tetraethyl orthosilicate (TEOS), high-density plasma (HDP) oxide, and polysilicon wafers were polished in subsequent examples. 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. Polysilicon wafers were obtained from WRS Materials and contained a 10 kÅ (1000 nm) polySi layer. Patterned HDP wafers were also polished in Examples 4 and 6. Patterned HDP wafers were obtained from Silyb and contained a 4 kÅ (400 nm) HDP oxide of STI1 with a 2 kÅ (200 nm) underlying polysilicon layer.

[0092] Example 1 The cerium oxide dispersion was prepared as follows: A cerium nitrate solution was prepared by combining 13.1 kg of 3 M cerium(III)(trivalent)(III) nitrate solution, 0.3 kg of 3 M lanthanum nitrate solution, 2.0 kg of 68% nitric acid (HNO3) 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 container under stirring and nitrogen bubbling.

[0093] An aqueous ammonia solution was prepared by combining 75 kg of deionized water and 13.1 kg of a 25% aqueous ammonia solution (so that the molar ratio of NH4OH in the aqueous ammonia solution to the total amount of cerium and lanthanum in the cerium nitrate solution was 9.0). The aqueous ammonia solution was then degassed in a 100 L jacketed reactor under stirring and nitrogen bubbling.

[0094] A cerium nitrate solution was then added to the aqueous ammonia solution at ambient temperature under nitrogen purging 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, the pH was acidified to 2 by adding 68% nitric acid.

[0095] The reaction mixture was then filtered and washed with deionized water. Washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm. 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.

[0096] The specific surface area of ​​BET was determined by nitrogen adsorption, and it was found to be 11.8 m² per gram. 2 The average particle size was 102 nm when measured by Horiba960 and 140 nm when measured by Malvern Zetasizer.

[0097] Example 2 Two polishing compositions were tested to evaluate the polishing rates of TEOS, HDP, and polysilicon. Each composition was prepared by combining a first pack (Pack A) with deionized water and the corresponding second pack (Pack B). In composition 2A, Pack A contained 2 wt percent control ceria (wet process ceria, HC60™, commercially available from Rhodia) at pH 3.5. In composition 2B, Pack A contained 1 wt part by weight of the raw material ceria dispersion described above in Example 1 and 4 wt parts by weight of deionized water. The ceria concentration was 2 wt percent and the pH was adjusted to 3.5. Pack B contained 5 mmol (mM) suberic acid at pH 4.

[0098] A portion of pack A was first combined with 6 parts deionized water, and then further combined with 3 parts of pack B to obtain a ready-to-use composition containing 0.2 weight percent ceria abrasive and 1.5 mM suberic acid.

[0099] Blanket TEOS, HDP, and polysilicon (PolySi) wafers were polished in Mirra® for 60 seconds under the conditions listed above. The polishing results are shown in Table 1. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). [Table 1]

[0100] As is readily apparent from the results shown in Table 1, the cubic ceria abrasive unexpectedly increased the TEOS removal rate by approximately 1.8x and the HDP removal rate by approximately 1.5x, while also reducing the polysilicon removal rate by more than 30 percent. As a result, the cubic ceria abrasive significantly increased the TEOS and HDP removal rates, and simultaneously, unexpectedly, increased the TEOS-to-polysilicon selectivity by 2.7x and the HDP-to-polysilicon selectivity by 2.2x (~100).

[0101] Example 3 Nine polishing compositions were tested to evaluate the TEOS, HDP, and polysilicon polishing rates. Each composition was prepared by combining Pack A with deionized water and the corresponding Pack B. For compositions 3A-3D, Pack A contained 2 wt percent of the control ceria described above in Example 2, at pH 3.5. For compositions 3E-3I, Pack A contained 1 wt part of the raw ceria dispersion described above in Example 1 and 4 wt parts of deionized water. The ceria concentration was 2 wt percent, and the pH was adjusted to 3.5. Pack B contained 5 mM succinic acid (3A and 3E), 5 mM glutaric acid (3B and 3F), 5 mM pimelic acid (3C and 3G), and 5 mM suberic acid (3D and 3H), at pH 4. For composition 3I, Pack B contained deionized water adjusted to pH 4.

[0102] A portion of pack A was first combined with 6 parts deionized water, and then further combined with 3 parts of pack B to obtain a ready-to-use composition containing 0.2 weight percent ceria abrasive and 1.5 mM diacitol (excluding composition 3I, which does not contain diacitol).

[0103] In compositions 3A to 3D, the TEOS blanket and polysilicon wafer were polished in Mirra® for 60 seconds under the conditions listed above. In compositions 3E to 3I, the TEOS blanket and HDP wafer were polished on a Logitech benchtop polishing tool with an E6088 pad at a downward force of 3 psi (20684.28 Pa), a platen speed of 88 rpm, a head speed of 85 rpm, and a slurry flow rate of 50 ml / min. The pad was conditioned in situ with Saesol DS8051 conditioner at a downward force of 6 pounds (2.7126 kg). The polishing results are shown in Tables 2A and 2B. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). [Table 2] [Table 3]

[0104] As is readily apparent from the results presented in Tables 2A and 2B, the TEOS removal rate increases with increasing carbon atom numbers in the diacitic acid (pimelic acid > glutaric acid > succinic acid) in cubic ceria abrasives, while the TEOS removal rate generally decreases with increasing carbon atom numbers in the diacitic acid (succinic acid > glutaric acid / pimelic acid > suberic acid) in the control wet ceria. Therefore, compositions containing cubic ceria abrasives are expected to advantageously achieve significantly higher removal rates and TEOS-to-polysilicon selectivity compared to those using control wet ceria. Compositions containing cubic ceria abrasives (particularly 3G and 3H) will also show a significant increase in TEOS removal rate when tested on Logitech polishing tools, which are known to have reduced removal rates compared to Mirra® tools.

[0105] Example 4 Two polishing compositions were tested to evaluate the TEOS, HDP, and polysilicon polishing rates on blanket wafers, as well as corrosion, dishing, and polysilicon loss on patterned wafers. Each composition was prepared by combining pack A with deionized water and the corresponding pack B. In composition 2A, pack A contained 2 wt percent of the control ceria described above in Example 2, at pH 3.5. In composition 2B, pack A contained 1 wt part of the raw material ceria dispersion described above in Example 1 and 4 wt parts of deionized water. The ceria concentration was 2 wt percent, and the pH was adjusted to 3.5. Pack B contained 3.3 mM polyethylene glycol dioxide 600, at pH 4.0.

[0106] A portion of pack A was first combined with 6 parts deionized water, and then further combined with 3 parts of pack B to obtain a ready-to-use composition containing 0.2 weight percent ceria abrasive and 1.0 mM polyethylene glycol dioxide 600.

[0107] Blanket TEOS, HDP, and polysilicon wafers were polished in Mirra® for 60 seconds under the conditions listed above. Pattern wafers were polished to the endpoint +100% under the same conditions. The polishing results are shown in Tables 3A and 3B. All removal rates (RR) are listed in angstroms per minute (Å(0.1 nm) / min). Dishing, corrosion, and polysilicon (PolySi) loss are listed in angstroms (Å(0.1 nm)) for many different line patterns (the first number refers to the line width in microns, and the second number refers to the pattern density). [Table 4] [Table 5]

[0108] As is readily apparent from the results described in Tables 3A and 3B, the cubic ceria abrasive unexpectedly increased the TEOS removal rate by approximately 1.5x and the HDP removal rate by approximately 1.7x, while also reducing the polysilicon removal rate by more than 15 percent. As a result, the cubic ceria significantly increased the TEOS and HDP removal rates, while simultaneously increasing the TEOS-to-polysilicon selectivity by almost 2x and the HDP-to-polysilicon selectivity by more than 2x. Furthermore, composition 4B containing the cubic ceria abrasive generally exhibited superior topographic performance (including corrosion, dishing, and polySi loss) compared to the control composition containing wet ceria. Since it is generally well known that higher TEOS removal rates degrade the topographic performance of abrasive compositions, such improved topography is significantly advantageous and unexpected.

[0109] Example 5 Six polishing compositions were tested to evaluate the TEOS, HDP, and polysilicon polishing rates on blanket wafers. Each composition was prepared by combining pack A with deionized water and the corresponding pack B. In compositions 5A, 5C, and 5E, pack A contained 2 wt percent of the control ceria described above in Example 2, at pH 3.5. In compositions 5B, 5D, and 5F, pack A contained 1 wt part of the raw material ceria dispersion described above in Example 1 and 4 wt parts of deionized water. The ceria concentration was 2 wt percent and the pH was adjusted to 3.5. Pack B contained 3.3 mM polyethylene glycol dioic acid (molecular weight approximately 600 g / mol) (5A and 5B), 6.6 mM polyethylene glycol dioic acid 600 (5C and 5D), or 10 mM polyethylene glycol dioic acid 600 (5E and 5F), at pH 4.

[0110] A portion of Pack A was first combined with 6 parts deionized water, and then further combined with 3 parts of Pack B to obtain a time-of-use composition containing 0.2 weight percent ceria abrasive. The time-of-use diacitic acid concentrations are listed in Table 4A. [Table 6]

[0111] Blanket TEOS, HDP, and polysilicon wafers were polished in Mirra® for 60 seconds under the conditions listed above. The polishing results are shown in Table 4B. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). [Table 7]

[0112] As is readily apparent from the results shown in Table 4B, compositions containing cubic ceria abrasives (5B, 5D, and 5E) can produce high TEOS and HDP removal rates and high polysilicon selectivity at higher diacitor charges. With 2 mM diacitor (5C and 5D), the cubic ceria abrasives increased the TEOS and HDP removal rates to approximately 2.2x and 2.7x, respectively. Furthermore, compositions containing cubic ceria abrasives exhibited excellent oxide (TEOS and HDP)-to-polysilicon selectivity at all diacitor charges.

[0113] Example 6 Six polishing compositions were tested to evaluate the HDP and polysilicon polishing rates on blanket wafers, as well as dishing and corrosion on patterned wafers. Each composition was prepared by combining pack A with deionized water and the corresponding pack B. In composition 6A, pack A contained 2 wt percent of the control ceria described above in Example 2, at pH 3.5. For each of compositions 6B to 6F, pack A was prepared using the raw material ceria dispersion and deionized water described above in Example 1. The ceria concentration was 0.5 wt percent (6B and 6C), 1.25 wt percent (6D), or 2 wt percent (6E and 6F), and the pH was adjusted to 3.5. Pack B for composition 6A contained 5 mM polyethylene glycol diacitate (molecular weight approximately 600 g / mol) at pH 4. Pack B, relating to compositions 6B to 6F, contained suberic acid at pH 4, with 5 mM (6B and 6E), 6.25 mM (6D), or 7.5 mM (6C and 6F).

[0114] A portion of Pack A was first combined with 6 parts deionized water, and then further combined with 3 parts of Pack B to obtain the time-of-use compositions listed in Table 5A. [Table 8]

[0115] Blanket HDP and polysilicon wafers were polished in Mirra® for 60 seconds under the conditions listed above. Pattern wafers were polished to the endpoint +100% under the same conditions. The polishing results are shown in Tables 5B and 5C. All removal rates (RR) are listed in angstroms per minute (Å(0.1nm) / min). Dishing and corrosion are listed in angstroms (Å(0.1nm)). [Table 9] [Table 10]

[0116] As is readily apparent from the results presented in Tables 5B and 5C, compositions containing cubic ceria abrasive particles exhibit high HDP removal rates and very high HDP-to-polysilicon selectivity (>200) at very low abrasive loads (0.05 wt percent in 6B). At higher abrasive loads (0.2 wt percent in 6E and 6F), very high HDP removal rates were observed along with HDP-to-polysilicon selectivity of approximately 100. Composition 6D exhibited both high HDP removal rates and high HDP-to-polysilicon selectivity. Improved topography (dishing and corrosion compared to control 6A) was observed for all compositions across all features (with very few exceptions). Composition 6D, in particular, showed significantly improved topography across all features. Even with 200 percent over-polishing (OP), composition 6D outperformed the control. As described above in Example 4, it is generally well known that a higher oxide removal rate degrades the topographic performance of the polishing composition; therefore, such improved topography is significantly advantageous and unexpected.

[0117] Example 7 Two abrasive compositions were tested to evaluate the polishing speed in carbon-doped spin-on glass (SOG) low-k dielectrics. Compositions 7A and 7B were prepared by mixing packs A and B in a 1:1 ratio such that the concentration at use was half of that listed below for each individual pack. Pack A contained 0.5 wt percent ceria abrasive, 389 wt ppm picolinic acid, and 14 ppm Kordek MLX biocide, and had a pH of 4. Composition 7A contained the control ceria described above in Example 2. Composition 7B contained cubic ceria abrasive particles prepared as described above in Example 1. Pack B contained 117 wt ppm polyethylene glycol diacid (molecular weight approximately 600 g / mol), 117 wt ppm crotonic acid, and 83 wt ppm Kordek MLX biocide, and had a pH of 4. Pack B of composition 7A further contained 233 ppm by weight of GPoly OKS-1180 (butanediol vinyl alcohol copolymer available from Mitsubishi Chemical).

[0118] Substrates containing a carbon-doped silicon dioxide SOG layer were obtained from Brewer Science and polished on a Logitech benchtop polishing tool with an E6088 pad at a downward force of 1.5 psi (10342.14 Pa), a platen speed of 88 rpm, a head speed of 85 rpm, and a slurry flow rate of 50 ml / min. The pads were conditioned in situ with Saesol DS8051 conditioner at a downward force of 6 pounds (2.7126 kg). Polishing results are shown in Table 6. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). The carbon-doped silicon dioxide SOG layer contained carbon doping levels ranging from 68–72 percent carbon to 90–95 percent carbon and was heat-treated using low, medium, or high temperatures. The control material was essentially carbon-free. [Table 11]

[0119] As readily apparent from the data presented in Table 6, composition 7B demonstrated significantly improved removal rates across a wide range of high-carbon doped silicon oxide films. The improvement in removal rates ranged from approximately 15 percent to approximately 290 percent, depending on the film type. Furthermore, composition 7B advantageously achieved the improved rates without using the butanediol vinyl alcohol copolymer used in composition 7A.

[0120] Example 8 Three abrasive compositions were tested to evaluate the effect of lanthanum doping levels in cubic ceria abrasive particles on the TEOS removal rate. Composition 8A contained 0.28 wt percent control ceria (wet process ceria, HC60™, commercially available from Rhodia). Composition 8B contained 0.28 wt percent cubic ceria abrasive particles containing 2.5 mol 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 8C contained 0.28 wt percent cubic ceria abrasive particles containing 10 mol percent lanthanum oxide and was prepared by diluting the ceria dispersion described in the following paragraphs with 34 parts water to 1 part ceria dispersion. Compositions 8A to 8C each had a pH of 4.

[0121] A cerium oxide dispersion was prepared as follows: A cerium nitrate solution was prepared by combining 11.5 kg of 3 M cerium(III)(trivalent) nitrate solution, 1.3 kg of 3 M lanthanum nitrate solution, 1.86 kg of 68% nitric acid (HNO3) 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 container under stirring and nitrogen bubbling.

[0122] An aqueous ammonia solution was prepared by combining 70 kg of deionized water and 14 kg of a 25% aqueous ammonia solution (so that the molar ratio of NH4OH in the aqueous ammonia solution to the total amount 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.

[0123] A cerium nitrate solution was then added to an aqueous ammonia solution at ambient temperature under nitrogen purging and with the same stirring. The temperature of the reaction mixture was then increased to 88°C and maintained at that temperature for 13.5 hours. The reaction mixture was then allowed to cool, and under cooling, the pH was acidified to 2 by adding 68% nitric acid.

[0124] The reaction mixture was then filtered and washed with deionized water. Washing was repeated when the conductivity of the washing solution was less than 0.04 mS / cm. Deionized water was added to adjust the final concentration of cubic ceria abrasive to 10 weight percent. The cubic ceria abrasive particles contained 10 mole percent lanthanum oxide and 90 mole percent cerium oxide.

[0125] The specific surface area of ​​BET was determined by nitrogen adsorption, and it was found to be 8.6 m² per gram. 2 The average particle size, as measured by the Malvern Zetasizer, was 142 nm.

[0126] Blanket TEOS wafers were polished for 60 seconds using the Mirra® tool under the conditions listed above. The polishing results are shown in Table 7. All removal rates (RR) are listed in angstroms per minute (Å (0.1 nm) / min). [Table 12]

[0127] As is readily apparent from the data in Table 7, compositions 8B and 8C exhibited equivalent TEOS removal rates, exceeding 1.6x the removal rate of composition 8A.

[0128] In the context describing the present invention (particularly in the context of the following claims), the terms “a,” “an,” and “the,” and similar references, should be interpreted as covering both singular and plural, unless otherwise indicated herein or clearly contradicted by the context. The terms “comprising,” “having,” “including,” and “containing,” should be interpreted as open-ended terms (i.e., “including but not limited to”), unless otherwise indicated herein. The enumeration of value ranges herein is intended merely as a convenient way to refer individually to each distinct value within that range, unless otherwise indicated herein, and each distinct value is incorporated herein as if it were individually enumerated herein. All methods described herein may be carried out in any preferred order, unless otherwise indicated herein or clearly contradicted by the context. Any use of any example or illustrative term provided herein (e.g., "such as") is intended solely to further illustrate the invention and not to imply any limitation within its scope, unless otherwise explicitly claimed. No term herein should be construed as suggesting that any unclaimed element is essential to the practical application of the invention.

[0129] Preferred embodiments of the present invention are described herein, including the best modes 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 that those skilled in the art will use such variations appropriately, and the inventors also intend practical applications of the invention other than those specifically described herein. Accordingly, the invention includes all modifiers and equivalents of the subject matter described herein in the claims, as permitted by applicable law. Furthermore, any combination of the above elements in all possible variations is incorporated into the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0130] It will be understood that this disclosure includes many more embodiments than those included above in the examples. These embodiments include, but are not limited to, the embodiments described in the appended claims. The following embodiments can be cited as examples of the present invention. (Note 1) Liquid carrier; Cubic ceria abrasive particles dispersed in the liquid carrier; and Organic diacitors A chemical mechanical polishing composition containing the following: (Note 2) The composition according to Appendix 1, wherein the cubic ceria abrasive particles contain a mixture of cerium oxide and lanthanum oxide. (Note 3) The composition according to Appendix 1, wherein the cubic ceria abrasive particles have a molar ratio of lanthanum to lanthanum + cerium in the range of about 1 to about 15 percent. (Note 4) The cubic ceria abrasive particles are approximately 3 m 2 / g ~ approx. 14m 2 The composition described in Appendix 1, having a BET surface area within the range of / g. (Note 5) The composition according to Appendix 1, wherein the cubic ceria abrasive particles have an average particle size of about 50 to about 500 nm. (Note 6) The composition according to Appendix 1, comprising approximately 0.01 to approximately 1 weight percent of the cubic ceria abrasive particles at the time of use. (Note 7) The composition according to Appendix 1, wherein the diacid is a linear saturated dicarboxylic acid, an unsaturated dicarboxylic acid, a substituted dicarboxylic acid, or an aromatic dicarboxylic acid. (Note 8) The composition according to Appendix 7, wherein the diacid comprises a linear saturated dicarboxylic acid. (Note 9) The composition described in Appendix 8, wherein the aforementioned diacid comprises glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or a combination thereof. (Note 10) The composition according to Appendix 8, wherein the aforementioned diacid comprises pimelic acid, suberic acid, azelaic acid, sebacic acid, or a combination thereof. (Note 11) The composition according to Appendix 8, wherein the aforementioned diacid is suberic acid. (Note 12) The composition according to Appendix 1, wherein the aforementioned diacid contains polyethylene glycol diacid. (Note 13) The composition according to Appendix 12, wherein the polyethylene glycol diacid has a molecular weight in the range of about 100 to about 1200 g / mol. (Note 14) The composition described in Appendix 1, having a pH in the range of approximately 3 to approximately 5. (Note 15) The composition according to Appendix 1, which contains at least 1 mM of the aforementioned organic diacid at the time of use. (Note 16) At the time of use, the cubic ceria abrasive particles are present in an amount of approximately 0.01 to approximately 1 weight percent: The cubic ceria abrasive particles contain a mixture of cerium oxide and lanthanum oxide and have an average particle size of about 50 to about 500 nm; The aforementioned organic diacid is suberic acid, polyethylene glycol diacid, or a mixture thereof; It has a pH in the range of approximately 3 to 5. The composition described in Appendix 1. (Note 17) The aforementioned organic diacid is polyethylene glycol diacid; The composition described in Appendix 16, further comprising picolinic acid. (Note 18) The composition described in Appendix 17, further comprising crotonic acid. (Note 19) The composition according to Appendix 1, further comprising at least one of a cationic surfactant, anionic surfactant, net neutral surfactant, cationic polymer, anionic polymer, nonionic polymer, and biocide. (Note 20) A method for chemically and mechanically polishing a substrate containing a silicon dioxide dielectric material: (a)(i) a liquid carrier; (ii) cubic ceria abrasive particles dispersed in the liquid carrier; and (iii) an organic diacid to provide an abrasive composition; (b) bringing the substrate into contact with the provided abrasive composition; (c) Transferring the abrasive composition to the substrate; and (d) Polishing the substrate by abrading it and removing a portion of the silicon oxide dielectric material from the substrate. The method, including the method described above. (Note 21) The substrate further comprises a polysilicon material; The removal rate selectivity between the silicon oxide material and the polysilicon material exceeds approximately 50:1. The method described in Appendix 20. (Note 22) The silicon oxide dielectric material is a carbon-doped silicon oxide material; The removal rate of the carbon-doped silicon oxide material exceeds approximately 1000 Å / min. The method described in Appendix 20. (Note 23) The method according to Appendix 22, wherein the carbon-doped silicon oxide material contains more than 50 mole percent of carbon. (Note 24) The method according to Appendix 20, wherein the aforementioned diacid includes polyethylene glycol diacid. (Note 25) The method according to Appendix 24, wherein the abrasive composition further comprises at least one of picolinic acid and crotonic acid.

Claims

1. Liquid carrier; Dispersed in the liquid carrier are cubic ceria abrasive particles in an amount of 0.01 to 1 weight percent at the time of use; and Organic diacitors containing polyethylene glycol diacitic acid with a molecular weight of approximately 600 at concentrations ranging from 0.1 mM to 20 mM. A chemical mechanical polishing composition for polishing a substrate containing TEOS or HDP oxide, including the following.

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

3. The composition according to claim 1, wherein the cubic ceria abrasive particles have a molar ratio of lanthanum to lanthanum + cerium in the range of 1 to 15 percent.

4. The cubic ceria abrasive particles are 3m 2 / g~14m 2 The composition according to claim 1, having a BET surface area within the range of / g.

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

6. The composition according to claim 1, wherein the diacid comprises a linear saturated dicarboxylic acid, an unsaturated dicarboxylic acid, a substituted dicarboxylic acid, or an aromatic dicarboxylic acid.

7. The composition according to claim 6, wherein the diacid comprises a linear saturated dicarboxylic acid.

8. The composition according to claim 7, wherein the diacid comprises glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, or a combination thereof.

9. The composition according to claim 7, wherein the diacid comprises pimelic acid, suberic acid, azelaic acid, sebacic acid, or a combination thereof.

10. The composition according to claim 7, wherein the diacid comprises suberic acid.

11. The composition according to claim 1, having a pH in the range of 3 to 5.

12. The composition according to claim 1, comprising at least 1 mM of the organic diacid at the time of use.

13. The cubic ceria abrasive particles contain a mixture of cerium oxide and lanthanum oxide and have an average particle size of 50 to 500 nm; The organic diacid is either polyethylene glycol diacid or a mixture of suberic acid and polyethylene glycol diacid; Having a pH in the range of 3 to 5 The composition according to claim 1.

14. The aforementioned organic diacid is polyethylene glycol diacid; The composition according to claim 13, further comprising picolinic acid.

15. The composition according to claim 14, further comprising crotonic acid.

16. The composition according to claim 1, further comprising at least one of a cationic surfactant, anionic surfactant, net neutral surfactant, cationic polymer, anionic polymer, nonionic polymer, and biocide.

17. A method for chemically and mechanically polishing a substrate containing TEOS or HDP oxide, the following: (a) (i) a liquid carrier; (ii) cubic ceria abrasive particles dispersed in the liquid carrier at a concentration of 0.01 to 1 weight percent at the time of use; and (iii) an organic diacid containing polyethylene glycol diacid having a molecular weight of about 600 at a concentration of 0.1 mM to 20 mM; (b) bringing the substrate into contact with the provided abrasive composition; (c) Moving the abrasive composition with respect to the substrate; and (d) Polishing the substrate by abrading it and removing a portion of the TEOS or HDP oxide from the substrate. The method, including the method described above.

18. The substrate further comprises a polysilicon material; The removal rate selectivity between the TEOS or HDP oxide and the polysilicon material exceeds 50:

1. The method according to claim 17.

19. The TEOS or HDP oxide is a carbon-doped silicon oxide material; The removal rate of the carbon-doped silicon oxide material exceeds 1000 Å / min. The method according to claim 17.

20. The method according to claim 19, wherein the carbon-doped silicon oxide material contains more than 50 mole percent of carbon.

21. The method according to claim 17, wherein the abrasive composition further comprises at least one of picolinic acid and crotonic acid.

Images