Titanium oxide-based chemical mechanical polishing composition for high-concentration doped boron silicon films

Abstract

The present invention provides a chemical mechanical polishing composition comprising (a) titanium oxide abrasive; (b) an oxidizing agent; and (c) water, having a pH of about 7 or less. The present invention also provides a method for chemically polishing a substrate, particularly a substrate having a boron-doped polysilicon layer on its surface, using the composition.

Description

[Background technology]

[0001]

[0001] Compositions and methods for planarizing or polishing the surface of a substrate are well known in the art. Polishing compositions (also known as polishing slurries) generally contain an abrasive material in a liquid carrier and are applied to the surface by bringing the surface into contact with a polishing pad impregnated with the polishing composition. Typical abrasive materials include silicon dioxide, cerium oxide, aluminum oxide, zirconium oxide, and tin oxide. Polishing compositions are generally used with a polishing pad (e.g., a polishing cloth or disc). The abrasive material may be incorporated into the polishing pad instead of being suspended in the polishing composition, or in addition to being suspended in it.

[0002]

[0002] Boron-doped polysilicon or boron-polysilicon alloys are increasingly being used as patterning hard masks in the manufacture of advanced node memory devices such as dynamic random access memory (DRAM). Due to the high levels of boron in the polysilicon material, it can be difficult to achieve high removal rates of this material by chemomechanical planarization (CMP). In addition to requiring high removal rates for boron-polysilicon films, some memory device schemes also require extremely low removal rates for silicon nitride and / or silicon oxide, which can function as a stop layer in the device film stack. This indicates the need for selectivity in CMP. In addition, some memory device schemes also require a high removal rate for titanium nitride, which can also be used in the manufacture of some memory devices. The ability to adjust the relative removal rates of boron-doped polysilicon and / or titanium nitride to silicon oxide and / or silicon nitride would be a desirable feature of polishing compositions and methods useful in the manufacture of devices.

[0003]

[0003] Therefore, there is still a need in the art for polishing boron polysilicon layers and titanium nitride layers with high removal rate and selectivity for boron polysilicon and titanium nitride. The present invention provides such a polishing composition and method. Such advantages and other advantages of the present invention, as well as additional features of the invention, will become apparent from the description of the invention provided herein. [Overview of the project]

[0004]

[0004] The present invention provides a chemical mechanical polishing composition comprising (a) titanium oxide abrasive; (b) an oxidizing agent; and (c) water, wherein the chemical mechanical polishing composition has a pH of about 7 or less.

[0005]

[0005] The present invention further provides (i) a substrate, (ii) a polishing pad, and (iii) a chemical mechanical polishing composition, wherein the chemical mechanical polishing composition comprises (a) titanium oxide abrasive; (b) an oxidizing agent; and (c) water, and has a pH of about 7 or less, and (iv) a method comprising bringing a substrate into contact with the polishing pad and the chemical mechanical polishing composition, and (v) moving the polishing pad and the chemical mechanical polishing composition against the substrate to remove at least a portion of the substrate by friction in order to polish the substrate. [Modes for carrying out the invention]

[0006]

[0006] The present invention provides a chemical mechanical polishing composition comprising (a) titanium oxide abrasive; (b) an oxidizing agent; and (c) water, wherein the chemical mechanical polishing composition has a pH of about 7 or less.

[0007]

[0007] This polishing composition contains titanium oxide abrasive. The terms “abrasive” and “abrasive particles” as used herein are interchangeable and can refer to any dispersion of abrasive particles. In other words, the terms “abrasive” and “abrasive particles” can refer to (i) a plurality of single types of abrasives or abrasive particles and / or (ii) a plurality of two or more types of abrasives or abrasive particles.

[0008]

[0008] Titanium oxide (i.e., titanium dioxide) exists as at least seven polymorphs, four of which are found in nature. The three most common natural forms of titanium oxide are rutile, anatase, and titanite, while the rutile and anatase forms are usually obtained through synthesis. All forms of titanium oxide have the same empirical formula TiO2, but each has a different crystal structure. The rutile form ("rutile") is the most thermodynamically stable form of titanium oxide. The crystal structure of rutile is a tetragonal crystal in which Ti-O octahedra share four edges. The anatase form ("anatase") has a tetragonal crystal structure similar to rutile, except that the Ti-O octahedra share four vertices instead of four edges. Anatase spontaneously transforms into the more stable rutile at temperatures above approximately 915°C. The least common of the three forms, and rarely used commercially, is the platylate form of titanite ("platylate"), which has an orthorhombic structure that spontaneously transforms into rutile at temperatures around 750°C.

[0009]

[0009] In the art, many methods for preparing titanium dioxide are known. Synthesis methods include gas-phase synthesis and liquid-phase synthesis. In gas-phase synthesis of titanium dioxide, a volatile titanium(IV) compound is mixed with water vapor and / or oxygen to hydrolyze the titanium(IV) compound and produce titanium dioxide, and the gaseous flow is passed through a heating zone. The titanium dioxide thus produced is isolated by cooling the gaseous flow and collecting the particulate titanium dioxide. For example, U.S. Patent No. 4,842,832 teaches a method for synthesizing titanium dioxide by vaporizing a volatile titanium(IV) compound, such as titanium tetrachloride or titanium tetraalkoxide compound, combining the vapor with water vapor and / or oxygen and a carrier gas, and heating the resulting gaseous mixture in the gas phase to a temperature of 250-600°C. The vapor is then cooled to obtain spherical titanium dioxide particles, which may be amorphous, rutile, anatase, or a mixture thereof. U.S. Patent No. 4,241,042 describes a method for synthesizing titanium oxide by heating a liquid aerosol of a hydrolyzable titanium(IV) compound, such as titanium tetrachloride or a titanium tetraalkoxide compound, in contact with water vapor in a carrier gas in the presence of an optionally selected nucleating agent. The vapor is then cooled to obtain spherical titanium oxide particles. These spherical particles can be subjected to a heat treatment step of 250–1100°C before or after the recovery step, which increases the percentage of rutile spherical titanium oxide particles.

[0010]

[0010] In the art, many liquid-phase synthesis methods for titanium dioxide are known. Methods that enable the preparation of titanium dioxide particles having a specific rutile / anatase ratio are well known in the literature. For example, the preparation of titanium dioxide particles via precipitation from a liquid titanium(IV) salt produces a mixture of particles having rutile and anatase forms, the ratio of rutile to anatase in which the particle is produced depends in part on the specific titanium(IV) compound used as the starting material and the specific reaction conditions (see, for example, Wilska, Acta Chemica Scandinavica, 8:1796-1801 (1954)).

[0011]

[0011] The phase content of titanium dioxide (e.g., the weight ratio of rutile to anatase) can be determined through several techniques. One suitable technique is X-ray diffraction (XRD). Rutile and anatase exhibit distinct X-ray diffraction patterns, whether they exist individually as pure microcrystals or together in a particular sample of titanium dioxide. The ratio of the intensities of the peaks (i.e., diffraction lines) in a mixed sample containing both rutile and anatase can be related to the concentrations of rutile and anatase by preparing a mixture of rutile and anatase with known amounts of each microcrystal, and by using a calibration curve obtained by obtaining its X-ray diffraction. Although the diffraction line intensities as a function of concentration are not equal for rutile and anatase, determining the ratio of the diffraction line intensities of rutile and anatase in a sample containing both is a useful approximation of the weight ratio of rutile to anatase in the sample. See, for example, Wilska, supra. and its references. Typically, the useful X-ray diffraction lines characteristic of rutile have a lattice plane spacing of approximately 3.24 Å, while the useful X-ray diffraction lines characteristic of anatase have a lattice plane spacing of approximately 3.51 Å.

[0012]

[0012] The titanium oxide abrasive may contain any suitable titanium oxide (i.e., titanium dioxide). In some embodiments, the titanium oxide abrasive is a titanium oxide abrasive mixture containing rutile-type titanium oxide and / or anatase-type titanium oxide. In some embodiments, the X-ray diffraction pattern of the titanium oxide abrasive has an X / Y ratio of about 0.5 or greater (where X is the intensity of the peak in the X-ray diffraction curve representing a lattice plane spacing of about 3.24 Å, correlated with the rutile content of the particles, and Y is the intensity of the peak in the X-ray diffraction curve representing a lattice plane spacing of about 3.51 Å, correlated with the anatase content of the sample). In other words, the majority of the titanium oxide abrasive may be in the form of rutile-type titanium oxide. In some embodiments, the X / Y ratio is 0.75 or greater (e.g., about 1 or greater, or about 1.5 or greater, or about 2 or greater, or possibly about 3 or greater). In some embodiments, the titanium oxide abrasive consists substantially of rutile (i.e., more than 95% of the particles are rutile), in which case the X / Y ratio approaches infinity. In one embodiment, the titanium oxide abrasive consists solely of rutile form (i.e., the intensity of the peak in the X-ray diffraction curve representing a lattice plane spacing of about 3.51 Å is undetectable). In some embodiments, titanium oxide abrasive present in amounts less than 5%, e.g., less than 2.5%, less than 1%, less than 0.5%, less than 0.1%, or less than 0.01% (e.g., rutile-type titanium oxide abrasive) may contain additional polymorphs (i.e., other than rutile and anatase). In some embodiments, the titanium oxide abrasive contains no additional polymorphs (i.e., other than rutile and anatase) in detectable amounts.

[0013]

[0013] Preferably, the titanium oxide abrasive (e.g., rutile-type titanium oxide abrasive) is pure titanium oxide or substantially pure titanium oxide; however, small amounts of impurities and dopants may be present in the rutile-type titanium oxide abrasive. In some embodiments, the titanium oxide is prepared using a method that employs dopants such as tin compounds to influence the ratio of rutile to anatase in the titanium oxide. Thus, the abrasive may contain small amounts (e.g., about 5% by weight or less, about 4% by weight or less, about 2% by weight or less, or about 1% by weight or less) of materials other than titanium oxide itself. In some embodiments, the titanium oxide abrasive is substantially pure rutile-type titanium oxide (i.e., about 99% by weight or more of titanium oxide and 95% or more of the particles are rutile).

[0014]

[0014] Titanium oxide abrasives may or may not be modified (e.g., surface modified). For example, titanium oxide abrasives can be surface modified with polyethylene glycol, silane, or a combination thereof. Suitable polyethylene glycol and silane compounds for modifying titanium oxide abrasives will be readily apparent to those skilled in the art. In some embodiments, titanium oxide abrasives are surface modified with a combination of polyethylene glycol and silane. For example, the surface of a titanium oxide abrasive can be modified with a compound of the following formula: In the above formula, n is an integer from about 2 to about 100, for example, from about 2 to about 50, from about 2 to about 25, or from about 2 to about 20. In some embodiments, the titanium oxide abrasive is either surface-modified or has no surface modification.

[0015]

[0015] The titanium oxide abrasive particles can have any suitable average particle size (i.e., average particle diameter). If the average abrasive particle size is too small, the abrasive composition may not exhibit a sufficient removal rate. Conversely, if the average abrasive particle size is too large, the abrasive composition may exhibit undesirable abrasive performance, such as a poor substrate defect rate.

[0016]

[0016] Therefore, the titanium oxide polishing particles may have an average particle size of about 10 nm or more, for example, about 20 nm or more, about 25 nm or more, about 30 nm or more, about 35 nm or more, about 40 nm or more, about 45 nm or more, or about 50 nm or more. Alternatively or additionally, the titanium oxide polishing particles may have an average particle size of about 300 nm or less, for example, about 250 nm or less, about 225 nm or less, about 200 nm or less, about 175 nm or less, about 150 nm or less, about 125 nm or less, about 100 nm or less, about 75 nm or less, or about 50 nm or less. Therefore, the titanium oxide polishing particles may have an average particle size defined by any two of the aforementioned endpoints.

[0017]

[0017] For example, titanium oxide polishing particles range from about 10 nm to about 300 nm, for example, about 10 nm to about 250 nm, about 10 nm to about 225 nm, about 10 nm to about 200 nm, about 10 nm to about 175 nm, about 10 nm to about 150 nm, about 10 nm to about 125 nm, about 10 nm to about 100 nm, about 20 nm to about 300 nm, about 20 nm to about 250 nm, about 20 nm to about 225 nm, about 20 nm to about 200 nm, about 20 nm to about 175 nm, about 20 nm to about 150 nm, about 20 nm to about 125 nm, about 20 nm to about 100 nm, about 30 nm to about 300 nm, about 30 nm to about 250 nm, about 30 nm to about 225 nm, about 30 nm to about 20 It can have an average particle size of 0 nm, approximately 30 nm to approximately 175 nm, approximately 30 nm to approximately 150 nm, approximately 30 nm to approximately 125 nm, approximately 30 nm to approximately 100 nm, approximately 40 nm to approximately 300 nm, approximately 40 nm to approximately 250 nm, approximately 40 nm to approximately 225 nm, approximately 40 nm to approximately 200 nm, approximately 40 nm to approximately 175 nm, approximately 40 nm to approximately 150 nm, approximately 40 nm to approximately 125 nm, approximately 40 nm to approximately 100 nm, approximately 50 nm to approximately 300 nm, approximately 50 nm to approximately 250 nm, approximately 50 nm to approximately 225 nm, approximately 50 nm to approximately 200 nm, approximately 50 nm to approximately 175 nm, approximately 50 nm to approximately 150 nm, approximately 50 nm to approximately 125 nm, or approximately 50 nm to approximately 100 nm. In some embodiments, the titanium oxide abrasive has an average particle size of about 10 nm to about 300 nm or an average particle size of about 50 nm to about 150 nm.

[0018]

[0018] In the case of non-spherical abrasive particles, the particle size is the diameter of the smallest sphere that encloses the particle. The particle size of the abrasive can be measured using any suitable technique, for example, the laser diffraction technique. Suitable particle size measuring instruments are available, for example, from Malvern Instruments (Malvern, UK). In this regard, the average particle size referred to herein refers to the average particle size of all titanium oxide particles present in the abrasive composition. For example, the average particle size of a group of rutile particles present in the abrasive composition will not usually be equal to the average particle size of a group of anatase particles, but preferably the average particle size of a group of rutile particles and the average particle size of a group of anatase particles are within the range described herein, individually and as a whole.

[0019]

[0019] Titanium oxide abrasive can be present in the polishing composition in any appropriate amount. If the amount of abrasive in the polishing composition of the present invention is too small, the composition may not exhibit a sufficient polishing rate. Conversely, if the amount of abrasive in the polishing composition is too large, the polishing composition may exhibit undesirable polishing performance and / or may be cost-inefficient and / or may lack stability. The polishing composition may contain titanium oxide abrasive in about 10% by weight or less, for example, about 9% by weight or less, about 8% by weight or less, about 7% by weight or less, about 6% by weight or less, about 5% by weight or less, about 4% by weight or less, about 3% by weight or less, about 2% by weight or less, about 1% by weight or less, about 0.9% by weight or less, about 0.8% by weight or less, about 0.7% by weight or less, about 0.6% by weight or less, or about 0.5% by weight or less. Alternatively, or additionally, the polishing composition may contain about 0.001% by weight or more of titanium oxide abrasive material, for example, about 0.005% by weight or more, about 0.01% by weight or more, 0.05% by weight or more, about 0.1% by weight or more, about 0.2% by weight or more, about 0.3% by weight or more, about 0.4% by weight or more, about 0.5% by weight or more, or about 1% by weight or more of titanium oxide abrasive material. Thus, the polishing composition may, if necessary, contain titanium oxide abrasive material in any amount limited by any two of the aforementioned endpoints.

[0020]

[0020] For example, in some embodiments, the titanium oxide abrasive is present in an amount of about 0.001% to about 10% by weight of the abrasive composition, for example, about 0.001% to about 8% by weight, about 0.001% to about 6% by weight, about 0.001% to about 5% by weight, about 0.001% to about 4% by weight, about 0.001% to about 2% by weight, about 0.001% to about 1% by weight, and about 0.001% to about 0% by weight. 0.5% by weight, approximately 0.01% to approximately 10% by weight, approximately 0.01% to approximately 8% by weight, approximately 0.01% to approximately 6% by weight, approximately 0.01% to approximately 5% by weight, approximately 0.01% to approximately 4% by weight, approximately 0.01% to approximately 2% by weight, approximately 0.01% to approximately 1% by weight, approximately 0.05% to approximately 10% by weight, approximately 0.05% to approximately 8% by weight, approximately 0.05% to approximately 6% by weight, approximately 0.05% by weight From approximately 5% by weight, from approximately 0.05% to approximately 4% by weight, from approximately 0.05% to approximately 2% by weight, from approximately 0.05% to approximately 1% by weight, from approximately 0.1% to approximately 10% by weight, from approximately 0.1% to approximately 8% by weight, from approximately 0.1% to approximately 6% by weight, from approximately 0.1% to approximately 5% by weight, from approximately 0.1% to approximately 4% by weight, from approximately 0.1% to approximately 2% by weight, from approximately 0.1% to approximately 1% by weight, from approximately 0.5% to approximately 10% by weight, Titanium oxide abrasive can be present in the abrasive composition in amounts of approximately 0.5% to approximately 8% by weight, approximately 0.5% to approximately 5% by weight, approximately 0.5% to approximately 4% by weight, approximately 0.5% to approximately 2% by weight, approximately 0.5% to approximately 1% by weight, approximately 1% to approximately 10% by weight, approximately 1% to approximately 8% by weight, approximately 1% to approximately 6% by weight, approximately 1% to approximately 5% by weight, approximately 1% to approximately 4% by weight, or approximately 1% to approximately 2% by weight. In some embodiments, the abrasive composition contains approximately 0.001% to approximately 10% by weight of titanium oxide abrasive. In some embodiments, the abrasive composition contains approximately 0.025% to approximately 5% by weight of titanium oxide abrasive. In other embodiments, the abrasive composition contains approximately 0.001% to approximately 0.05% by weight of titanium oxide abrasive.

[0021]

[0021] The chemical mechanical polishing composition contains an oxidizing agent. The oxidizing agent may be any suitable compound that can oxidize the substrate (e.g., boron-doped polysilicon, silicon nitride, silicon oxide, or titanium nitride). For example, the oxidizing agent can be selected from oxone, cerium ammonium nitrate, peroxides (e.g., hydrogen peroxide), periodates (e.g., sodium periodate or potassium periodate), iodates (e.g., sodium iodate, potassium iodate, or ammonium iodate), persulfates (e.g., sodium persulfate, potassium persulfate, or ammonium persulfate), chlorates (e.g., sodium chlorate or potassium chlorate), chromates (e.g., sodium chromate or potassium chromate), permanganates (e.g., sodium permanganate, potassium permanganate, or ammonium permanganate), bromates (e.g., sodium bromate or potassium bromate), perbromates (e.g., sodium perbromate or potassium perbromate), ferrates (e.g., potassium ferrate), perrheniumates (e.g., ammonium perrhenate), perrutheniumates (e.g., tetrapropylammonium perruthenate), and combinations thereof. The oxidizing agent may be in acid form (e.g., persulfate), salt form (e.g., ammonium persulfate), or a mixture thereof. In some embodiments, the oxidizing agent includes alkali metal (e.g., sodium or potassium) salts of peroxides, periodates, iodates, persulfates, chlorates, chromates, permanganates, bromates, perbromates, ironates, perrhenates, perrutheniumates, or combinations thereof.

[0022]

[0022] In some embodiments, the oxidizing agent is selected from permanganates (e.g., sodium permanganate, potassium permanganate, or ammonium permanganate), cerium ammonium nitrate, and combinations thereof. In some embodiments, the oxidizing agent is cerium ammonium nitrate. In other embodiments, the oxidizing agent is a permanganate such as potassium permanganate (e.g., sodium permanganate, potassium permanganate, or ammonium permanganate).

[0023]

[0023] The polishing composition can contain any suitable amount of an oxidizing agent. The polishing composition can contain about 20 wt% or less of the oxidizing agent, for example, about 15 wt% or less, about 10 wt% or less, about 9 wt% or less, about 8 wt% or less, about 7 wt% or less, about 6 wt% or less, about 5 wt% or less, about 4 wt% or less, about 3 wt% or less, or about 2 wt% or less of the oxidizing agent. Alternatively or additionally, the polishing composition can contain about 0.1 wt% or more of the oxidizing agent, for example, about 0.5 wt% or more, about 1 wt% or more, about 2 wt% or more, about 3 wt% or more, about 4 wt% or more, or about 5 wt% or more of the oxidizing agent. Accordingly, the polishing composition can contain the oxidizing agent in any amount limited by any two of the above endpoints, as required.

[0024]

[0024] For example, in some embodiments, the oxidizing agent is present in an amount of about 0.1% by weight to about 20% by weight, for example, about 0.1% by weight to about 15% by weight, about 0.1% by weight to about 10% by weight, about 0.1% by weight to about 9% by weight, about 0.1% by weight to about 8% by weight, about 0.1% by weight to about 7% by weight, about 0.1% by weight to about 6% by weight, about 0.1% by weight to about 5% by weight, about 0.1% by weight to about 4% by weight, about 0.1% by weight to about 3% by weight, and about 0.1% by weight to about 2% by weight %, approximately 0.5% to approximately 20% by weight, approximately 0.5% to approximately 15% by weight, approximately 0.5% to approximately 10% by weight, approximately 0.5% to approximately 9% by weight, approximately 0.5% to approximately 8% by weight, approximately 0.5% to approximately 7% by weight, approximately 0.5% to approximately 6% by weight, approximately 0.5% to approximately 5% by weight, approximately 0.5% to approximately 4% by weight, approximately 0.5% to approximately 3% by weight, approximately 0.5% to approximately 2% by weight, approximately 1% to approximately 20% by weight, approximately 1% to approximately 15% by weight Approximately 1% to 10% by weight, approximately 1% to 9% by weight, approximately 1% to 8% by weight, approximately 1% to 7% by weight, approximately 1% to 6% by weight, approximately 1% to 5% by weight, approximately 1% to 4% by weight, approximately 1% to 3% by weight, approximately 1% to 2% by weight, approximately 2% to 20% by weight, approximately 2% to 15% by weight, approximately 2% to 10% by weight, approximately 2% to 9% by weight, approximately 2% to 8% by weight, approximately 2% to 7% by weight It can be present in the abrasive composition in amounts of %, approximately 2% to approximately 6% by weight, approximately 2% to approximately 5% by weight, approximately 2% to approximately 4% by weight, approximately 2% to approximately 3% by weight, approximately 3% to approximately 20% by weight, approximately 3% to approximately 15% by weight, approximately 3% to approximately 10% by weight, approximately 3% to approximately 9% by weight, approximately 3% to approximately 8% by weight, approximately 3% to approximately 7% by weight, approximately 3% to approximately 6% by weight, approximately 3% to approximately 5% by weight, or approximately 3% to approximately 4% by weight. In some embodiments, the abrasive composition comprises at least 1% by weight of an oxidizing agent (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight), at least 2% by weight of an oxidizing agent (e.g., 2% to 20% by weight, 2% to 10% by weight, or 2% to 5% by weight), or at least 3% by weight of an oxidizing agent (e.g., 3% to 20% by weight, 3% to 10% by weight, or 3% to 5% by weight).

[0025]

[0025] The polishing composition may comprise ferric ions, cobalt ions, manganese ions, an organic acid, or a combination thereof.

[0026]

[0026] The ferric ions may be provided in the form of any suitable ferric salt. A non-limiting example of a suitable ferric salt is ferric nitrate. The polishing composition may comprise any suitable amount of ferric ions. For example, the polishing composition may comprise from about 0.005 wt% to about 1 wt% of ferric ions, for example, from about 0.01 wt% to about 0.9 wt%, from about 0.02 wt% to about 0.8 wt%, from about 0.03 wt% to about 0.6 wt%, from about 0.03 wt% to about 0.4 wt%, from about 0.03 wt% to about 0.2 wt%, or from about 0.03 wt% to about 0.1 wt% of ferric ions.

[0027]

[0027] In some embodiments, the polishing composition is substantially free of ferric ions. In the context of the present invention, "substantially free of ferric ions" means that the polishing composition comprises no more than about 0.01 wt%, for example, no more than 0.005 wt%, no more than about 0.001 wt%, or no more than about 0.0001 wt% of ferric ions, or no ferric ions can be detected in the polishing composition.

[0028]

[0028] The cobalt ions may be provided in the form of any suitable cobalt salt. A non-limiting example of a suitable cobalt salt is cobalt acetate. The polishing composition may comprise any suitable amount of cobalt ions. For example, the polishing composition may comprise from about 0.005 wt% to about 1 wt% of cobalt ions, for example, from about 0.01 wt% to about 0.9 wt%, from about 0.02 wt% to about 0.8 wt%, from about 0.03 wt% to about 0.6 wt%, from about 0.03 wt% to about 0.4 wt%, from about 0.03 wt% to about 0.2 wt%, or from about 0.03 wt% to about 0.1 wt% of cobalt ions.

[0029]

[0029] In some embodiments, the polishing composition is substantially free of cobalt ions. In the context of the present invention, "substantially free of cobalt ions" means that the polishing composition contains about 0.01% by weight or less, for example, 0.005% by weight or less, about 0.001% by weight or less, or about 0.0001% by weight or less of cobalt ions, or that no cobalt ions can be detected in the polishing composition.

[0030]

[0030] Manganese ions can be provided in the form of any suitable manganese salt. A non-limiting example of a suitable manganese salt is manganese acetate. The abrasive composition can contain any suitable amount of manganese ions. For example, the abrasive composition can contain about 0.005% to about 1% by weight of manganese ions, e.g., about 0.01% to about 0.9% by weight, about 0.02% to about 0.8% by weight, about 0.03% to about 0.6% by weight, about 0.03% to about 0.4% by weight, about 0.03% to about 0.2% by weight, or about 0.03% to about 0.1% by weight of manganese ions.

[0031]

[0031] In some embodiments, the polishing composition is substantially free of manganese ions. In the context of the present invention, "substantially free of manganese ions" means that the polishing composition contains about 0.01% by weight or less of manganese ions, for example, 0.005% by weight or less, about 0.001% by weight or less, or about 0.0001% by weight or less of manganese ions, or that manganese ions cannot be detected in the polishing composition.

[0032]

[0032] The polishing composition may contain an organic acid. The organic acid can be any suitable organic acid. Non-limiting examples of suitable organic acids include tartaric acid, lactic acid, formic acid, acetic acid, maleic acid, citric acid, L-ascorbic acid, picolinic acid, and malonic acid. In some embodiments, the organic acid is selected from maleic acid, citric acid, L-ascorbic acid, picolinic acid, malonic acid, and combinations thereof.

[0033]

[0033] The abrasive composition may contain an organic acid at any appropriate concentration. For example, the abrasive composition may contain an organic acid at about 1 mM or more, for example, about 2 mM or more, about 3 mM or more, about 4 mM or more, or about 5 mM or more. Alternatively or additionally, the abrasive composition may contain an organic acid at about 100 mM or less, for example, about 50 mM or less, about 25 mM or less, about 20 mM or less, about 19 mM or less, about 18 mM or less, about 17 mM or less, about 16 mM or less, or about 15 mM or less. Thus, the abrasive composition may contain an organic acid in any amount limited by any two of the aforementioned endpoints. For example, the abrasive composition may contain an organic acid in a concentration of about 1 mM to about 20 mM, such as about 1 mM to about 15 mM, about 2 mM to about 15 mM, about 3 mM to about 15 mM, about 3 mM to about 12 mM, about 1 mM to about 12 mM, or about 1 mM to about 10 mM. In some embodiments, the abrasive composition contains an organic acid in a concentration of about 1 mM to about 100 mM.

[0034]

[0034] In some embodiments, the polishing composition is substantially free of organic acids. In the context of the present invention, "substantially free of organic acids" means that the polishing composition contains organic acids at a concentration of about 1 mM or less, for example, about 0.5 mM or less, about 1 μM or less, or about 0.5 μM or less, or that organic acids cannot be detected in the polishing composition. In some embodiments, the polishing composition is substantially free of ferric ions, substantially free of cobalt ions, substantially free of manganese ions, and / or substantially free of organic acids.

[0035]

[0035] In some embodiments, the abrasive composition further comprises a dispersant. The dispersant can be any suitable dispersant. For example, the dispersant can be a nonionic polymer dispersant or an anionic polymer dispersant. For example, the dispersant may include polyvinyl alcohol (PVA), glycerin, polyethylene glycol (PEG), polypropylene glycol (PPG), polyvinylpyrrolidone (PVP), polyacrylic acid, polymethacrylic acid, ammonium polyacrylate, ammonium polymethacrylate, polyacrylic acid, maleic acid, or a combination thereof. In some embodiments, the dispersant may include polyalkylene oxides such as polyethylene oxide, polypropylene oxide, or a combination thereof.

[0036]

[0036] The abrasive composition may contain any suitable amount of dispersant. The abrasive composition may contain about 10% by weight or less of dispersant, for example, about 9% by weight or less, about 8% by weight or less, about 7% by weight or less, about 6% by weight or less, about 5% by weight or less, about 4% by weight or less, about 3% by weight or less, or about 2% by weight or less of dispersant. Alternatively or additionally, the abrasive composition may contain about 0.1% by weight or more of dispersant, for example, about 0.5% by weight or more, about 1% by weight or more, or about 2% by weight or more of dispersant. Thus, the abrasive composition may contain any amount of dispersant limited by any two of the aforementioned endpoints, as needed.

[0037]

[0037] For example, in some embodiments, the dispersant is present in amounts of about 0.1% to about 10% by weight, about 0.1% to about 9% by weight, about 0.1% to about 8% by weight, about 0.1% to about 7% by weight, about 0.1% to about 6% by weight, about 0.1% to about 5% by weight, about 0.1% to about 4% by weight, about 0.1% to about 3% by weight, about 0.1% to about 2% by weight, about 0.5% to about 10% by weight, about 0.5% to about 9% by weight, about 0.5% to about 8% by weight, about 0.5% to about 7% by weight, about 0.5% to about 6% by weight, about 0.5% to about 5% by weight, about 0.5% to about 4% by weight, about 0. It can be present in the abrasive composition in amounts of 5% to about 3% by weight, about 0.5% to about 2% by weight, about 1% to about 10% by weight, about 1% to about 9% by weight, about 1% to about 8% by weight, about 1% to about 7% by weight, about 1% to about 6% by weight, about 1% to about 5% by weight, about 1% to about 4% by weight, about 1% to about 3% by weight, about 1% to about 2% by weight, about 2% to about 10% by weight, about 2% to about 9% by weight, about 2% to about 8% by weight, about 2% to about 7% by weight, about 2% to about 6% by weight, about 2% to about 5% by weight, about 2% to about 4% by weight, or about 2% to about 3% by weight. In some embodiments, the abrasive composition comprises about 0.1% to about 4% by weight of a dispersant, about 0.5% to about 4% by weight, about 0.5% to about 3% by weight, about 1% to about 4% by weight, or about 1% to about 3% by weight of a dispersant.

[0038]

[0038] The polishing composition contains water. The water can be any suitable water, for example, deionized water or distilled water. In some embodiments, the polishing composition may further contain one or more organic solvents in combination with water. For example, the polishing composition may further contain hydroxyl solvents such as methanol or ethanol, ketone solvents, amide solvents, and sulfoxide solvents.

[0039]

[0039] The abrasive composition can have any suitable pH. Typically, the abrasive composition has a pH of about 7 or less, for example, about 6.5 or less, about 6 or less, about 5.5 or less, about 5 or less, about 4.5 or less, or about 4 or less. Alternatively or additionally, the abrasive composition can have a pH of about -2 or more, for example, about -1.5 or more, about -1 or more, about 0.5 or more, about 0 or more, about 0.5 or more, about 1 or more, about 0.5 or more, or about 2 or more. Thus, the abrasive composition can have a pH limited by any two of the aforementioned endpoints.

[0040]

[0040] For example, the polishing composition is about -2 to about 7, for example, about -1.5 to about 7, about -1 to about 7, about -0.5 to about 7, about 0 to about 7, about 0.5 to about 7, about 1 to about 7, about 1.5 to about 7, about 2 to about 7, about -2 to about 6.5, about -1.5 to about 6.5, about -1 to about 6.5, about -0.5 to about 6.5, about 0 to about 6.5, about 0.5 From approximately 6.5, from approximately 1 to approximately 6.5, from approximately 1.5 to approximately 6.5, from approximately 2 to approximately 6.5, from approximately -2 to approximately 6, from approximately -1.5 to approximately 6, from approximately -1 to approximately 6, from approximately -0.5 to approximately 6, from approximately 0 to approximately 6, from approximately 0.5 to approximately 6, from approximately 1 to approximately 6, from approximately 1.5 to approximately 6, from approximately 2 to approximately 6, from approximately -2 to approximately 5.5, from approximately -1.5 to approximately 5.5, from approximately -1 to approximately 5.5, from approximately -0.5 to approximately 5. 5, approximately 0 to approximately 5.5, approximately 0.5 to approximately 5.5, approximately 1 to approximately 5.5, approximately 1.5 to approximately 5.5, approximately 2 to approximately 5.5, approximately -2 to approximately 5, approximately -1.5 to approximately 5, approximately -1 to approximately 5, approximately -0.5 to approximately 5, approximately 0 to approximately 5, approximately 0.5 to approximately 5, approximately 1 to approximately 5, approximately 1.5 to approximately 5, approximately 2 to approximately 5, approximately -2 to approximately 4.5, approximately -1.5 to approximately 4.5, approximately -1 to The pH can be approximately 4.5, approximately -0.5 to approximately 4.5, approximately 0 to approximately 4.5, approximately 0.5 to approximately 4.5, approximately 1 to approximately 4.5, approximately 1.5 to approximately 4.5, approximately 2 to approximately 4.5, approximately -2 to approximately 4, approximately -1.5 to approximately 4, approximately -1 to approximately 4, approximately -0.5 to approximately 4, approximately 0 to approximately 4, approximately 0.5 to approximately 4, approximately 1 to approximately 4, approximately 1.5 to approximately 4, and approximately 2 to approximately 4. In some embodiments, the chemical mechanical abrasive composition has a pH of approximately 6 or less. In some embodiments, the abrasive composition has a pH of approximately 5 or less or approximately 4 or less. In other embodiments, the abrasive composition has a pH of approximately 0 to approximately 7 or approximately 0 to approximately 4.

[0041]

[0041] The pH of the abrasive composition can be adjusted using any suitable acid or base. Non-limited examples of suitable acids include nitric acid, sulfuric acid, phosphoric acid, and organic acids such as formic acid and acetic acid. Non-limited examples of suitable bases include sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

[0042]

[0042] In some embodiments, the abrasive composition further comprises a buffer. The buffer can be any suitable compound capable of buffering (e.g., maintaining) the abrasive composition within a specific pH range. For example, the buffer can be selected from ammonium salts, alkali metal salts, alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, borates, amino acids, and combinations thereof.

[0043]

[0043] The chemical mechanical polishing composition optionally further comprises one or more additives. Examples of additives include conditioners, acids (e.g., sulfonic acid), complexing agents, chelating agents, biocides, scale inhibitors, and dispersants.

[0044]

[0044] In some embodiments, the abrasive composition further comprises a biocide. Non-limiting examples of suitable biocides include Kordek MLX TM These are isothiazolinone-based biocides such as those from DuPont, Wilmington, DE. The abrasive composition can contain any appropriate amount of biocide. For example, the abrasive composition can contain about 0.001% to about 0.2% by weight of biocide.

[0045]

[0045] In some embodiments, the present invention provides a chemical mechanical polishing composition comprising, or essentially consisting of, (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) of a permanganate (e.g., potassium permanganate); and (c) water, wherein the chemical mechanical polishing composition has a pH of about 7 or less.

[0046]

[0046] In some embodiments, the present invention provides a chemical mechanical polishing composition comprising, or essentially comprising, (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) a permanganate (e.g., potassium permanganate); (c) a dispersant; and (d) water, the chemical mechanical polishing composition having a pH of about 7 or less.

[0047]

[0047] In some embodiments, the present invention provides a chemical mechanical polishing composition comprising, or essentially consisting of, (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) of cerium ammonium nitrate; and (c) water, wherein the chemical mechanical polishing composition has a pH of about 7 or less.

[0048]

[0048] In some embodiments, the present invention provides a chemical mechanical polishing composition comprising, or essentially comprising, (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) cerium ammonium nitrate; (c) a dispersant; and (d) water, the chemical mechanical polishing composition having a pH of about 7 or less.

[0049]

[0049] Abrasive compositions can be manufactured by any suitable technique, many of which are known to those skilled in the art. Abrasive compositions can be prepared in batch or continuous processes. Generally, abrasive compositions are prepared by combining the components of an abrasive composition. As used herein, the term “components” includes individual components (e.g., titanium dioxide abrasive, oxidizing agent, optional pH adjuster, and / or any optional additive), as well as any combination of components (e.g., titanium dioxide abrasive, oxidizing agent, optional pH adjuster, and / or any optional additive).

[0050]

[0050] For example, an abrasive composition can be prepared by (i) providing all or part of a liquid carrier, (ii) dispersing titanium oxide abrasive, an oxidizing agent, an optional pH adjuster, and / or any optional additive using any suitable means for preparing such a dispersion, (iii) adjusting the pH of the dispersion as necessary, and (iv) optionally adding an appropriate amount of any other optional component and / or additive to the mixture.

[0051]

[0051] Alternatively, an abrasive composition can be prepared by (i) providing one or more components (e.g., an oxidizing agent, an optional pH adjuster, and / or any optional additive) in a titanium dioxide abrasive slurry; (ii) providing one or more components (e.g., a liquid carrier, an oxidizing agent, an optional pH adjuster, and / or any optional additive) in an additive solution; (iii) combining the titanium dioxide abrasive slurry and the additive solution to form a mixture; (iv) optionally adding an appropriate amount of any other optional additive to the mixture; and (v) adjusting the pH of the mixture as necessary.

[0052]

[0052] The polishing composition can be supplied as a one-package system comprising titanium dioxide abrasive, an oxidizing agent, an optional pH adjuster, and / or an optional additive, and water. Alternatively, the polishing composition of the present invention can be supplied as a two-package system comprising a titanium dioxide polishing slurry in a first package and an additive solution in a second package, wherein the titanium dioxide polishing slurry consists essentially of or comprises titanium dioxide abrasive and water, and the additive solution consists essentially of or comprises an oxidizing agent, an optional pH adjuster, and / or any of the optional additives. The two-package system makes it possible to adjust the properties of the polishing composition by changing the mixing ratio of the two packages, namely the titanium dioxide polishing slurry and the additive solution.

[0053]

[0053] Various methods can be employed to utilize such a two-package polishing system. For example, the titanium oxide polishing slurry and the additive solution can be delivered to the polishing table by different pipes that are coupled and connected at the outlet of the supply piping. The titanium oxide polishing slurry and the additive solution can be mixed shortly before or immediately before polishing, or they can be supplied onto the polishing table simultaneously. Furthermore, when mixing the two packages, deionized water can be added as needed to adjust the polishing composition and the resulting substrate polishing properties.

[0054]

[0054] Similarly, in connection with the present invention, three, four, or more package systems may be utilized, each of which contains different components, one or more optional components, and / or one or more of the same components of the chemical mechanical polishing composition of the present invention in different concentrations.

[0055]

[0055] To mix components contained in two or more storage devices to produce an abrasive composition at or near the point of use, the storage devices are typically provided with one or more flow lines from each storage device to the point of use of the abrasive composition (e.g., a platen, abrasive pad, or substrate surface). As used herein, “point of use” refers to the point at which the abrasive composition is applied to the substrate surface (e.g., the abrasive pad or the substrate surface itself). The term “flow line” means a channel from an individual storage container to the point of use of the components stored therein. Each of the flow lines can be connected directly to the point of use, or two or more flow lines can be joined at any point to form a single flow line leading to the point of use. Furthermore, any of the flow lines (e.g., individual flow lines or joined flow lines) can first be connected to one or more other devices (e.g., pump devices, measuring devices, mixing devices, etc.) before reaching the point of use of one or more components.

[0056]

[0056] The components of the polishing composition can be delivered independently to the point of use (for example, the components are delivered to the substrate surface and mixed there during the polishing process), or one or more of the components can be combined before being delivered to the point of use, for example, shortly before or immediately before being delivered to the point of use. Combining components "immediately before being delivered to the point of use" means that the components are combined within about 5 minutes of being added to the platen in a mixed state, for example, within about 4 minutes, 3 minutes, 2 minutes, 1 minute, 45 seconds, 30 seconds, or 10 seconds of being added to the platen in a combined state, or simultaneously with the delivery of the components at the point of use (for example, the components are combined in a dispenser). Components are also combined "immediately before being delivered to the point of use" if they are combined within 5 m of the point of use, for example, within 1 m of the point of use, or in some cases within 10 cm of the point of use (for example, within 1 cm of the point of use).

[0057]

[0057] If two or more components of the abrasive composition are combined before reaching the point of use, the components can be mixed in a flow line or delivered to the point of use without using a mixing device. Alternatively, one or more of the flow lines can be led to a mixing device to facilitate the combination of two or more components. Any suitable mixing device can be used. For example, the mixing device may be a nozzle or jet (e.g., a high-pressure nozzle or jet) through which two or more components flow. Alternatively, the mixing device may be a container-type mixing device including one or more inlets for introducing two or more components of the abrasive slurry into a mixer, and at least one outlet for discharging the mixed components from the mixer and delivering them to the point of use directly or via other elements of the device (e.g., via one or more flow lines). Furthermore, the mixing device may include a plurality of chambers, each having at least one inlet and at least one outlet, in which two or more components are combined. When using a container-type mixing device, the mixing device preferably includes a mixing mechanism to further facilitate the combination of components. Mixing mechanisms are commonly known in the art and include stirrers, blenders, agitators, paddle baffles, gas sparger systems, vibrators, and the like.

[0058]

[0058] The abrasive composition may also be provided as a concentrate intended to be diluted with an appropriate amount of water before use. In such embodiments, the concentrate of the abrasive composition contains the components of the abrasive composition 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 amounts within the appropriate range described above for each component. For example, the titanium dioxide abrasive, the oxidizing agent, an optional pH adjuster, and / or any optional additive may each be present in the concentrate in amounts approximately twice (e.g., approximately three times, approximately four times, or approximately five times) of the above-described concentration for each component, so that when the concentrate is diluted with an equal volume of water (e.g., two equal volumes of water, three equal volumes of water, or four equal volumes of water, respectively), each component is present in the abrasive composition in amounts within the range described above for each component. Furthermore, as will be understood by those skilled in the art, the concentrate may contain an appropriate proportion of water present in the final abrasive composition to ensure that the titanium dioxide abrasive, the oxidizing agent, an optional pH adjuster, and / or any optional additive are at least partially or completely dissolved in the concentrate.

[0059]

[0059] The present invention further provides (i) a substrate, (ii) a polishing pad, and (iii) a chemical mechanical polishing composition, wherein the chemical mechanical polishing composition comprises (a) a titanium oxide abrasive; (b) an oxidizing agent; and (c) water, and has a pH of about 7 or less, and (iv) a method for chemical mechanical polishing a substrate, comprising bringing the substrate into contact with the polishing pad and the chemical mechanical polishing composition, and (v) moving the polishing pad and the chemical mechanical polishing composition against the substrate to remove at least a portion of the substrate by friction in order to polish the substrate.

[0060]

[0060] The substrate can be any suitable substrate. In some embodiments, the substrate includes boron-doped polysilicon, such as a boron-polysilicon alloy. Thus, the method may include providing a substrate having a boron-doped polysilicon layer on its surface, at least a portion of the boron-doped polysilicon layer on the substrate surface being removed by friction to polish the substrate. Alternatively or additionally, the substrate may include a silicon nitride layer on its surface, a silicon oxide layer on its surface, a titanium nitride layer on its surface, or a combination thereof. For example, the method may include a substrate comprising (i) a silicon nitride layer on the surface of the substrate, wherein at least a portion of the silicon nitride layer on the surface of the substrate is removed by friction to polish the substrate; (ii) a silicon oxide layer on the surface of the substrate, wherein at least a portion of the silicon oxide layer on the surface of the substrate is removed by friction to polish the substrate; and / or (iii) a titanium nitride layer on the surface of the substrate, wherein at least a portion of the titanium nitride layer on the surface of the substrate is removed by friction to polish the substrate. In some embodiments, the substrate comprises a boron-doped polysilicon layer on the surface of the substrate in combination with the silicon oxide layer, the silicon nitride layer, and / or the titanium nitride layer on the surface of the substrate.

[0061]

[0061] Boron-doped polysilicon can be any suitable boron-doped polysilicon, many of which are known in the art. The polysilicon can have any suitable phase and can be amorphous, crystalline, or a combination thereof. The level of boron doping can be any suitable level. Generally, a boron-doped polysilicon layer contains at least 75% by weight of boron, at least 80% by weight of boron, at least 85% by weight of boron, or at least 90% by weight of boron. For example, a boron-doped polysilicon layer may contain approximately 75% to 99.9% by weight of boron, such as 75% to 99% by weight, 75% to 95% by weight, 75% to 90% by weight, 80% to 99.9% by weight, 80% to 99% by weight, 80% to 95% by weight, 80% to 90% by weight, 85% to 99.9% by weight, 85% to 99% by weight, 85% to 95% by weight, 85% to 95% by weight, 85% to 90% by weight, 90% to 99.9% by weight, 90% to 95% by weight, 95% to 99.9% by weight, or approximately 95% to 99% by weight of boron. In some embodiments, the boron-doped polysilicon layer contains at least 95% by weight of boron. While we do not wish to be bound by any particular theory, the compositions and methods provided herein are considered particularly suitable for polishing boron-doped polysilicon having high levels of boron doping (e.g., about 80% by weight or more, about 85% by weight or more, about 90% by weight or more, or about 95% by weight or more).

[0062]

[0062] The polishing composition of the present invention preferably exhibits a high removal rate when polishing a substrate containing boron-doped polysilicon by the method of the present invention. For example, when polishing a silicon wafer containing a boron-doped polysilicon layer by one embodiment of the present invention, the polishing composition preferably exhibits a removal rate of about 500 Å / min or more, for example, about 550 Å / min or more, about 600 Å / min or more, about 650 Å / min or more, about 700 Å / min or more, about 750 Å / min or more, about 800 Å / min or more, about 850 Å / min or more, about 900 Å / min or more, about 950 Å / min or more, about 1000 Å / min or more, about 1100 Å / min or more, about 1200 Å / min or more, about 1300 Å / min or more, about 1400 Å / min or more, about 1500 Å / This indicates the removal rate of boron-doped polysilicon at intervals of 1 minute or more, approximately 1600 Å / min or more, approximately 1700 Å / min or more, approximately 1800 Å / min or more, approximately 1900 Å / min or more, approximately 2000 Å / min or more, approximately 2100 Å / min or more, approximately 2200 Å / min or more, approximately 2300 Å / min or more, approximately 2400 Å / min or more, approximately 2500 Å / min or more, approximately 2600 Å / min or more, approximately 2700 Å / min or more, approximately 2800 Å / min or more, approximately 2900 Å / min or more, approximately 3000 Å / min or more, approximately 3500 Å / min or more, approximately 4000 Å / min or more, or approximately 4500 Å / min or more.

[0063]

[0063] In some embodiments in which the substrate further comprises titanium nitride, the titanium nitride can be any suitable titanium nitride, many of which are known in the art. The chemical mechanical polishing composition of the present invention preferably exhibits a high removal rate when polishing a substrate containing titanium oxide by the method of the present invention. For example, when polishing a substrate containing titanium nitride by one embodiment of the present invention, the polishing composition preferably has a rate of about 500 Å / min or more, for example, about 550 Å / min or more, about 600 Å / min or more, about 650 Å / min or more, about 700 Å / min or more, about 750 Å / min or more, about 800 Å / min or more, about 850 Å / min or more, about 900 Å / min or more, about 950 Å / min or more, about 1000 Å / min or more, about 1100 Å / min or more, about 1200 Å / min or more, about 1300 Å / min or more, about 1400 Å / min or more, about 1500 Å / min or more. It exhibits titanium nitride removal rates of approximately 1600 Å / min or more, approximately 1700 Å / min or more, approximately 1800 Å / min or more, approximately 1900 Å / min or more, approximately 2000 Å / min or more, approximately 2100 Å / min or more, approximately 2200 Å / min or more, approximately 2300 Å / min or more, approximately 2400 Å / min or more, approximately 2500 Å / min or more, approximately 2600 Å / min or more, approximately 2700 Å / min or more, approximately 2800 Å / min or more, approximately 2900 Å / min or more, approximately 3000 Å / min or more, approximately 3500 Å / min or more, approximately 4000 Å / min or more, or approximately 4500 Å / min or more.

[0064]

[0064] In some embodiments in which the substrate further contains silicon dioxide, the silicon dioxide can be any suitable silicon dioxide, many of which are known in the art. Suitable types of silicon dioxide include, but are not limited to, borosilicate glass (BPSG), tetraethyl orthosilicate (TEOS), plasma-enhanced tetraethyl orthosilicate (PETEOS), thermal oxides, undoped silicate glass, and high-density plasma (HDP) oxides. The chemical mechanical polishing compositions of the present invention preferably exhibit a low silicon dioxide removal rate when polishing a silicon dioxide-containing substrate by the method of the present invention. For example, when polishing a silicon dioxide substrate with one embodiment of the present invention, the polishing composition preferably exhibits a silicon dioxide removal rate of about 500 Å / min or less, for example, about 250 Å / min or less, about 200 Å / min or less, about 150 Å / min or less, about 100 Å / min or less, about 50 Å / min or less, about 25 Å / min or less, about 10 Å / min or less, or about 5 Å / min or less. In some embodiments, the polishing composition exhibits a silicon dioxide removal rate that is too low to be detected.

[0065]

[0065] In some embodiments, if the substrate further contains silicon nitride, the silicon nitride can be any suitable silicon nitride, many of which are known in the art. The chemical mechanical polishing compositions of the present invention preferably exhibit a low silicon nitride removal rate when polishing a silicon nitride-containing substrate by the method of the present invention. For example, when polishing a silicon nitride-containing substrate by one embodiment of the present invention, the polishing composition preferably exhibits a silicon nitride removal rate of about 500 Å / min or less, for example, about 250 Å / min or less, about 200 Å / min or less, about 150 Å / min or less, about 100 Å / min or less, about 50 Å / min or less, about 25 Å / min or less, about 10 Å / min or less, or about 5 Å / min or less. In some embodiments, the polishing composition exhibits a silicon nitride removal rate that is too low to be detected.

[0066]

[0066] The chemical mechanical polishing compositions of the present invention can be adjusted to provide effective polishing at a desired selective polishing rate on specific thin-layer materials while minimizing the removal of surface defects, flaws, corrosion, erosion, and stop layers. Selectivity can be controlled to some extent by changing the relative concentrations of the components of the polishing composition. Preferably, the chemical mechanical polishing compositions of the present invention can be used to polish substrates containing boron-doped polysilicon and silicon oxide on a surface layer, and the chemical mechanical polishing compositions provide polishing selectivity of boron-doped polysilicon to silicon oxide of about 5:1 or more (e.g., about 10:1 or more, about 15:1 or more, about 25:1 or more, about 50:1 or more, about 100:1 or more, or about 150:1 or more). Furthermore, the chemical mechanical polishing compositions of the present invention can be used to polish substrates containing boron-doped polysilicon and silicon nitride on a surface layer, and the chemical mechanical polishing compositions provide a polishing selectivity of about 3:1 or more (e.g., about 5:1 or more, about 10:1 or more, about 15:1 or more, about 25:1 or more, about 50:1 or more, about 100:1 or more, or about 150:1 or more) for boron-doped polysilicon to silicon nitride. Thus, in embodiments, when used to polish a substrate containing at least one layer of boron-doped polysilicon and at least one layer of silicon oxide and / or at least one layer of silicon nitride, the polishing compositions and polishing methods enable preferential removal of boron-doped polysilicon compared to the removal of silicon oxide and / or silicon nitride. As used herein, the term “polishing selectivity” refers to the ratio of the removal rates of two different thin-layer materials.

[0067]

[0067] The chemical mechanical polishing compositions of the present invention can also be used to polish substrates containing boron-doped polysilicon and titanium nitride on a surface layer, and the chemical mechanical polishing compositions provide polishing selectivity of boron-doped polysilicon to titanium nitride of about 20:1 or less (e.g., about 10:1 or less, about 5:1 or less, about 4:1 or less, about 3:1 or less, or about 2:1 or less). The chemical mechanical polishing compositions of the present invention preferably exhibit a high removal rate when polishing substrates containing both boron-doped polysilicon and titanium nitride by the method of the present invention. Therefore, the chemical mechanical polishing compositions of the present invention can be used to selectively remove boron-doped polysilicon and / or titanium nitride in the presence of silicon oxide and / or silicon nitride.

[0068]

[0068] The polishing compositions of the present invention preferably exhibit low particle defects when polishing a substrate, as determined by an appropriate technique. The particle defects on a substrate polished with the polishing compositions of the present invention can be determined by any appropriate technique. For example, the particle defects on a polished substrate can be determined using laser light scattering techniques such as dark-field normal beam composite (DCN) and dark-field oblique beam composite (DCO). Appropriate measuring instruments for evaluating particle selectivity can be obtained, for example, from KLA-Tencor (e.g., SURFSCAN operating at a 120 nm threshold or a 160 nm threshold). TM SPI measuring instrument.

[0069]

[0069] The chemical mechanical polishing composition and method of the present invention are particularly suitable for use in combination with a chemical mechanical polishing apparatus. Typically, this apparatus includes a platen that is in operation during use and has a velocity resulting from orbital motion, linear motion, or circular motion; a polishing pad that is in contact with the platen and moves with the platen during operation; and a carrier that is in contact with the substrate and holds the substrate to be polished by moving the substrate relative to the surface of the polishing pad. Polishing of the substrate is performed by bringing the substrate into contact with the polishing pad and the polishing composition of the present invention, and then moving the polishing pad relative to the substrate, thereby polishing the substrate by polishing at least a portion of it.

[0070]

[0070] The substrate can be polished with a chemical mechanical polishing composition using any suitable polishing pad (e.g., polishing surface). Suitable polishing pads include, for example, woven and nonwoven polishing pads. Furthermore, suitable polishing pads can include any suitable polymer having various densities, hardness, thickness, compressibility, rebound capacity under compression, and compression coefficient. Suitable polymers include, for example, polyvinyl chloride, polyvinyl fluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, co-molded products thereof, and mixtures thereof. Soft polyurethane polishing pads are particularly useful in combination with the polishing method of the present invention. Typical pads include, but are not limited to, SURFIN TM 000, SURFIN TM SSW1, SPM3100 (available for purchase from, for example, Emininess Technologies), POLITEX TM EPIC TM D100 pad (available from CMC Materials), IC1010 TM Pads (available for purchase from Dow, Inc.), and Fujibo POLYPAS TM 27 is included.

[0071]

[0071] Preferably, the chemical mechanical polishing apparatus further includes an in situ polishing endpoint detection system, many of which are known in the art. Techniques for inspecting and monitoring the polishing process by analyzing light or other radiation reflected from the surface of the substrate being polished are known in the art. Such methods are described, for example, in U.S. Patents 5,196,353, 5,433,651, 5,609,511, 5,643,046, 5,658,183, 5,730,642, 5,838,447, 5,872,633, 5,893,796, 5,949,927, and 5,964,643. Preferably, by inspecting or monitoring the progress of the polishing process with respect to the substrate being polished, it becomes possible to determine the polishing endpoint, i.e., when to terminate the polishing process with respect to a particular substrate.

[0072]

[0072] The substrate can be polished with any appropriate downforce. For example, the substrate can be polished with a downforce of about 1 psi or more, about 2 psi or more, about 3 psi or more, about 4 psi or more, or about 5 psi or more. Alternatively or additionally, the substrate can be polished with a downforce of about 10 psi or less, about 8 psi or less, about 6 psi or less, about 4 psi or less, or about 2 psi or less. Thus, the substrate can be polished with a downforce limited by any two of the aforementioned endpoints. For example, the substrate can be polished with a downforce of about 1 psi to about 10 psi, about 2 psi to about 10 psi, about 1 psi to about 8 psi, about 2 psi to about 8 psi, about 1 psi to about 6 psi, about 2 psi to about 6 psi, about 1 psi to about 4 psi, or about 2 psi to about 4 psi.

[0073]

[0073] In some embodiments, the present invention provides (i) a substrate comprising a boron-doped polysilicon layer on its surface, (ii) a polishing pad, and (iii) a chemical mechanical polishing composition comprising (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) of a permanganate (e.g., potassium permanganate); and (c) water, and having a pH of about 7 or less, and (iv) a method for chemically polishing a substrate comprising (iv) bringing the substrate into contact with the polishing pad and the chemical mechanical polishing composition, and (v) moving the polishing pad and the chemical mechanical polishing composition against the substrate to polish the substrate, thereby removing at least a portion of the boron-doped polysilicon layer on the surface of the substrate by friction.

[0074]

[0074] In embodiments, the present invention provides (i) a substrate comprising a boron-doped polysilicon layer on the surface of the substrate, (ii) a polishing pad, and (iii) a chemical mechanical polishing composition comprising (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) of a permanganate (e.g., potassium permanganate); (c) a dispersant; and (d) water, and having a pH of about 7 or less, and (iv) a method for chemically polishing a substrate comprising (iv) bringing the substrate into contact with the polishing pad and the chemical mechanical polishing composition, and (v) moving the polishing pad and the chemical mechanical polishing composition against the substrate to remove at least a portion of the boron-doped polysilicon layer on the surface of the substrate by friction in order to polish the substrate.

[0075]

[0075] In embodiments, the present invention provides (i) a substrate comprising a boron-doped polysilicon layer on its surface, (ii) a polishing pad, and (iii) a chemical mechanical polishing composition comprising (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) of cerium ammonium nitrate; and (c) water, having a pH of about 7 or less, and (iv) a method for chemically polishing a substrate comprising bringing the substrate into contact with the polishing pad and the chemical mechanical polishing composition, and (v) moving the polishing pad and the chemical mechanical polishing composition against the substrate to remove at least a portion of the boron-doped polysilicon layer on the surface of the substrate by friction in order to polish the substrate.

[0076]

[0076] In embodiments, the present invention provides (i) a substrate comprising a boron-doped polysilicon layer on its surface, (ii) a polishing pad, and (iii) a chemical mechanical polishing composition comprising (a) a titanium oxide abrasive; (b) at least 1% by weight (e.g., 1% to 20% by weight, 1% to 10% by weight, or 1% to 5% by weight) of cerium ammonium nitrate; (c) a dispersant; and (d) water, and having a pH of about 7 or less, and (iv) a method for chemical mechanical polishing a substrate, comprising (iv) bringing the substrate into contact with the polishing pad and the chemical mechanical polishing composition, and (v) moving the polishing pad and the chemical mechanical polishing composition against the substrate to polish the substrate, thereby removing at least a portion of the boron-doped polysilicon layer on the surface of the substrate by friction.

[0077]

[0077] The embodiments of the present invention described herein may be useful on their own or in combination with one or more other embodiments or forms. Some non-limiting embodiments of the present disclosure numbered 1 to 63 are provided below, without limitation. As will be apparent to those skilled in the art by reading this disclosure, each of the individually numbered embodiments may be used or combined with any of the individually numbered embodiments described above or below. This is intended to support all such combinations of embodiments and is not limited to the combinations of embodiments expressly provided below.

[0078] Embodiment

[0078] (1) In embodiment (1), (a) Titanium oxide abrasives; (b) Oxidizing agents; and (c) water A chemical mechanical polishing composition containing the following is presented: Chemical mechanical abrasive compositions have a pH of approximately 7 or less.

[0079]

[0079] (2) Embodiment (2) presents the polishing composition described in Embodiment (1), wherein the polishing composition has a pH of about 6 or less.

[0080]

[0080] (3) Embodiment (3) presents an abrasive composition according to Embodiment (1) or Embodiment (2), wherein the abrasive composition has a pH of about 5 or less.

[0081]

[0081] (4) Embodiment (4) presents an abrasive composition according to any one of Embodiments (1) to (3), wherein the abrasive composition contains about 0.001% to about 10% by weight of titanium oxide abrasive.

[0082]

[0082] (5) Embodiment (5) presents an abrasive composition according to any one of Embodiments (1) to (4), wherein the abrasive composition contains 0.025% to about 5% by weight of titanium oxide abrasive.

[0083]

[0083] (6) Embodiment (6) presents an abrasive composition according to any one of Embodiments (1) to (5), wherein the titanium oxide abrasive is substantially pure rutile-type titanium oxide.

[0084]

[0084] (7) Embodiment (7) presents an abrasive composition according to any one of Embodiments (1) to (6), wherein the titanium oxide abrasive has an average particle size of about 10 nm to about 300 nm.

[0085]

[0085] (8) Embodiment (8) presents an abrasive composition according to any one of Embodiments (1) to (7), wherein the titanium oxide abrasive has an average particle size of about 50 nm to about 150 nm.

[0086]

[0086] (9) Embodiment (9) presents an abrasive composition according to any one of Embodiments (1) to (8), wherein the oxidizing agent is selected from oxone, cerium ammonium nitrate, peroxide, periodate, iodate, persulfate, chlorate, chromate, permanganate, bromate, perbromate, ironate, perrheniumate, perrutheniumate, and combinations thereof.

[0087]

[0087] (10) Embodiment (10) presents an abrasive composition according to any one of Embodiments (1) to (9), wherein the oxidizing agent is selected from permanganate, cerium ammonium nitrate, and combinations thereof.

[0088]

[0088] (11) Embodiment (11) presents an abrasive composition according to any one of Embodiments (1) to (10), wherein the oxidizing agent is cerium ammonium nitrate.

[0089]

[0089] (12) Embodiment (12) presents an abrasive composition according to any one of Embodiments (1) to (10), wherein the oxidizing agent is potassium permanganate.

[0090]

[0090] (13) Embodiment (13) presents an abrasive composition according to any one of Embodiments (1) to (12), wherein the abrasive composition contains about 1% to about 20% by weight of an oxidizing agent.

[0091]

[0091] (14) Embodiment (14) presents an abrasive composition according to any one of embodiments (1) to (13), wherein the abrasive composition contains 2% to 20% by weight of an oxidizing agent.

[0092]

[0092] (15) Embodiment (15) presents an abrasive composition according to any one of Embodiments (1) to (14), wherein the abrasive composition contains 3% to 20% by weight of an oxidizing agent.

[0093]

[0093] (16) Embodiment (16) presents an abrasive composition according to any one of Embodiments (1) to (15), wherein the abrasive composition further comprises ferric ions.

[0094]

[0094] (17) Embodiment (17) presents the polishing composition described in Embodiment (16), wherein the polishing composition contains about 0.01% to about 1% by weight of ferric ions.

[0095]

[0095] (18) Embodiment (18) presents an abrasive composition according to any one of Embodiments (1) to (15) in which the abrasive composition substantially does not contain ferric ions.

[0096]

[0096] (19) Embodiment (19) presents an abrasive composition according to any one of Embodiments (1) to (18), wherein the abrasive composition further comprises an organic acid.

[0097]

[0097] (20) Embodiment (20) presents the polishing composition described in Embodiment (19), wherein the organic acid is selected from maleic acid, citric acid, L-ascorbic acid, picolinic acid, malonic acid, and combinations thereof.

[0098]

[0098] (21) Embodiment (21) presents an abrasive composition according to Embodiment (19) or Embodiment (20), wherein the abrasive composition contains about 1 mM to about 100 mM of an organic acid.

[0099]

[0099] (22) Embodiment (22) presents an abrasive composition according to any one of Embodiments (1) to (18), wherein the abrasive composition substantially does not contain an organic acid.

[0100]

[0100] (23) Embodiment (23) presents an abrasive composition according to any one of Embodiments (1) to (22), wherein the abrasive composition further comprises a buffer.

[0101]

[0101] (24) Embodiment (24) presents the polishing composition described in Embodiment (23), wherein the buffering agent is selected from ammonium salts, alkali metal salts, alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, borates, amino acids, and combinations thereof.

[0102]

[0102] (25) Embodiment (25) presents an abrasive composition according to any one of Embodiments (1) to (24), wherein the abrasive composition further comprises a dispersant.

[0103]

[0103] (26) Embodiment (26) presents the polishing composition of Embodiment (25), wherein the dispersant contains a polyalkylene oxide.

[0104]

[0104] (27) Embodiment (27) is a method of chemical mechanical polishing of a substrate, (i) To provide a substrate, (ii) To provide a polishing pad, (iii) To provide a chemical mechanical polishing composition, the chemical mechanical polishing composition is (a) Titanium oxide abrasives; (b) Oxidizing agents; and (c) water Includes, To provide a chemical mechanical polishing composition having a pH of approximately 7 or less, (iv) bringing the substrate into contact with the polishing pad and the chemical mechanical polishing composition, (v) To polish the substrate, the polishing pad and the chemical mechanical polishing composition are moved against the substrate, and at least a portion of the substrate is removed by friction. A method including this is presented.

[0105]

[0105] (28) Embodiment (28) presents the method described in Embodiment (27), wherein the abrasive composition has a pH of about 6 or less.

[0106]

[0106] (29) Embodiment (29) presents the method described in Embodiment (27) or Embodiment (28), wherein the abrasive composition has a pH of about 5 or less.

[0107]

[0107] (30) Embodiment (30) presents a method according to any one of Embodiments (27) to (29), wherein the abrasive composition comprises about 0.001% to about 10% by weight of titanium oxide abrasive.

[0108]

[0108] (31) Embodiment (31) presents a method according to any one of Embodiments (27) to (30), wherein the abrasive composition comprises about 0.025% to about 5% by weight of titanium oxide abrasive.

[0109]

[0109] (32) Embodiment (32) presents a method according to any one of embodiments (27) to (31), wherein the titanium oxide abrasive is substantially pure rutile-type titanium oxide.

[0110]

[0110] (33) Embodiment (33) presents a method according to any one of Embodiments (27) to (32), wherein the titanium oxide abrasive has an average particle size of about 10 nm to about 300 nm.

[0111]

[0111] (34) Embodiment (34) presents a method according to any one of Embodiments (27) to (33), wherein the titanium oxide abrasive has an average particle size of about 50 nm to about 150 nm.

[0112]

[0112] (35) Embodiment (35) presents a method according to any one of Embodiments (27) to (34), wherein the oxidizing agent is selected from oxone, cerium ammonium nitrate, peroxides, periodates, iodates, persulfates, chlorates, chromates, permanganates, bromates, perbromates, ironates, perrhenates, perrutheniumates, and combinations thereof.

[0113]

[0113] (36) Embodiment (36) presents a method according to any one of Embodiments (27) to (35), wherein the oxidizing agent is selected from permanganate, cerium ammonium nitrate, and combinations thereof.

[0114]

[0114] (37) Embodiment (37) presents a method according to any one of Embodiments (27) to (36), wherein the oxidizing agent is cerium ammonium nitrate.

[0115]

[0115] (38) Embodiment (38) presents a method according to any one of Embodiments (27) to (36), wherein the oxidizing agent is potassium permanganate.

[0116]

[0116] (39) Embodiment (39) presents a method according to any one of Embodiments (27) to (38), wherein the abrasive composition contains 1% to 20% by weight of an oxidizing agent.

[0117]

[0117] (40) Embodiment (40) presents a method according to any one of Embodiments (27) to (39), wherein the abrasive composition contains 2% to 20% by weight of an oxidizing agent.

[0118]

[0118] (41) Embodiment (41) presents a method according to any one of Embodiments (27) to (40), wherein the abrasive composition contains 3% to 20% by weight of an oxidizing agent.

[0119]

[0119] (42) Embodiment (42) presents a method according to any one of Embodiments (27) to (41), wherein the abrasive composition further comprises ferric ions.

[0120]

[0120] (43) Embodiment (43) presents the method according to Embodiment (42), wherein the abrasive composition contains about 0.01% to about 1% by weight of ferric ions.

[0121]

[0121] (44) Embodiment (44) presents a method according to any one of Embodiments (27) to (41), wherein the abrasive composition is substantially free of ferric ions.

[0122]

[0122] (45) Embodiment (45) presents a method according to any one of Embodiments (27) to (44), wherein the abrasive composition further comprises ferric ions.

[0123]

[0123] (46) Embodiment (46) presents the method according to Embodiment (45), wherein the organic acid is selected from maleic acid, citric acid, L-ascorbic acid, picolinic acid, malonic acid, and combinations thereof.

[0124]

[0124] (47) Embodiment (47) presents the method according to Embodiment (45) or Embodiment (46), wherein the abrasive composition contains an organic acid in an amount of about 1 mM to about 100 mM.

[0125]

[0125] (48) Embodiment (48) presents a method according to any one of Embodiments (27) to (44), wherein the abrasive composition is substantially free of organic acids.

[0126]

[0126] (49) Embodiment (49) presents a method according to any one of Embodiments (27) to (48), wherein the abrasive composition further comprises a buffer.

[0127]

[0127] (50) Embodiment (50) presents the method according to Embodiment (49), wherein the buffer is selected from ammonium salts, alkali metal salts, alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, borates, amino acids, and combinations thereof.

[0128]

[0128] (51) Embodiment (51) presents a method according to any one of Embodiments (27) to (50), wherein the abrasive composition further comprises a dispersant.

[0129]

[0129] (52) Embodiment (52) presents the method of Embodiment (51) in which the dispersant contains a polyalkylene oxide.

[0130]

[0130] (53) Embodiment (53) presents a method according to any one of embodiments (27) to (52), wherein the substrate includes a boron-doped polysilicon layer on the surface of the substrate, and at least a portion of the boron-doped polysilicon layer on the surface of the substrate is removed by friction to polish the substrate.

[0131]

[0131] (54) Embodiment (54) presents the method of Embodiment (53) wherein the boron-doped polysilicon layer contains at least 80% by weight of boron.

[0132]

[0132] (55) Embodiment (55) presents the method of Embodiment (53) wherein the boron-doped polysilicon layer contains at least 85% by weight of boron.

[0133]

[0133] (56) Embodiment (56) presents the method according to Embodiment (53), wherein the boron-doped polysilicon layer contains at least 90% by weight of boron.

[0134]

[0134] (57) Embodiment (57) presents a method according to any one of embodiments (53) to (56), wherein the substrate further comprises a silicon nitride layer on the surface of the substrate, and at least a portion of the silicon nitride layer on the surface of the substrate is removed by friction to polish the substrate.

[0135]

[0135] (58) Embodiment (58) presents the method of Embodiment (57) wherein the chemical mechanical polishing composition provides polishing selectivity between boron-doped polysilicon and silicon nitride in a ratio of about 3:1 or more.

[0136]

[0136] (59) Embodiment (59) presents a method according to any one of embodiments (53) to (58), wherein the substrate further comprises a silicon oxide layer on the surface of the substrate, and at least a portion of the silicon oxide layer on the surface of the substrate is removed by friction to polish the substrate.

[0137]

[0137] (60) Embodiment (60) presents the method of Embodiment (59) wherein the chemical mechanical polishing composition provides polishing selectivity between boron-doped polysilicon and silicon oxide in a ratio of about 5:1 or more.

[0138]

[0138] (61) Embodiment (61) presents a method according to any one of embodiments (53) to (60), wherein the substrate further comprises a titanium nitride layer on the surface of the substrate, and at least a portion of the titanium nitride layer on the surface of the substrate is removed by friction to polish the substrate.

[0139]

[0139] (62) Embodiment (62) presents the method according to Embodiment (61), wherein the chemical mechanical polishing composition provides polishing selectivity between boron-doped polysilicon and titanium nitride in a ratio of about 5:1 or less.

[0140]

[0140] (63) Embodiment (63) presents the method according to Embodiment (61) or (62), wherein the chemical mechanical polishing composition provides polishing selectivity between boron-doped polysilicon and silicon oxide in a ratio of about 3:1 or less.

Examples

[0141]

[0141] The following examples further illustrate the present invention, but it goes without saying that they should not be construed as limiting the scope thereof in any sense.

[0142] Example 1

[0142] The following abbreviations are used throughout the examples: removal rate (RR); boron-doped polysilicon (BSi); silicon oxide (Ox); titanium nitride (TiN); weight percent (wt.%), and pounds per square inch (psi).

[0143]

[0143] This example demonstrates the effect of the types and amounts of abrasive particles and oxidizing agents on the polishing performance of polishing compositions prepared according to the present invention.

[0144]

[0144] Polishing compositions 1A to 1F contained 0.025 wt.% of silicon oxide (SiO₂) abrasive particles or 1 wt.% of titanium oxide (TiO₂) abrasives, 2 wt.% of polyethylene oxide dispersant exclusively for titanium oxide (TiO₂) abrasives, and oxidizing agents and additives shown in Table 1. A / B mixing was used for all formulations, the particle dispersion (pack A) was adjusted to pH 2.85 and mixed with the oxidizing agent (pack B) in a constant ratio to obtain a final slurry composition for polishing silicon oxide, titanium nitride, and boron polysilicon alloys. The final slurry had a pH of approximately 1 at the point of use.

[0145]

[0145] A patterned substrate comprising a tetraethyl orthosilicate (i.e., silicon oxide (Ox)) layer coated on a wafer, a boron-doped polysilicon (BSi) layer containing approximately 95 wt.% of boron, or a titanium nitride (TiN) layer was polished using a Logitech 2 benchtop polisher at a downforce of 3 PSI (20.55 kPa) on SAESOL TMNexPlanar conditioned with a product commercially identified as DS8051 (SAESOL Diamond Ind. Co. Ltd.) TM Polishing was performed using a U5890 pad (CMC Materials Inc.) with polishing compositions 1A to 1F as specified in Table 1. The Logitech polishing parameters were as follows: head speed = 86 rpm, platen speed = 93 rpm, total flow rate = 50 mL / min. All patterned substrates were polished for 60 seconds. The removal rate was calculated by measuring the film thickness using spectroscopic ellipsometry and subtracting the final thickness from the initial thickness. The results are shown in Table 1. The selectivity (Å / min) in Table 1 indicates the polishing rate of BSi and TiN compared to the polishing rate of TEOS (i.e., Ox). Table 1. Removal rate of abrasive composition as a function of oxidizing agent and abrasive material TIFF2026530512000002.tif98170

[0146]

[0146] As is clear from the results shown in Table 1, the silicon oxide compositions containing cerium ammonium nitrate (CAN) and optional additional oxidizing agents such as persulfate and iodate, as shown in Comparative Example polishing compositions 1A, 1B, and 1C, exhibited low TiN removal rates. Table 1 also shows that the addition of citric acid, as shown in Comparative Example polishing composition 1D, resulted in a slight increase in the TiN removal rate. Replacing the silicon oxide abrasive with titanium oxide abrasive in the absence of cerium ammonium nitrate (CAN), as shown in Comparative Example polishing composition 1E, did not result in any increase in the TiN removal rate. However, polishing composition 1F of the present invention, containing titanium oxide and cerium ammonium nitrate (CAN), exhibited high TiN and BSi removal rates while maintaining a low Ox removal rate. Therefore, Table 1 shows that titanium oxide abrasives and oxidizing agents preferably provide high TiN and BSi removal rates while maintaining a low Ox removal rate.

[0147] Example 2

[0147] This example demonstrates the effect of a dispersant on the polishing performance of the polishing composition prepared according to the present invention.

[0148]

[0148] Polishing compositions 2A to 2D contained 0.1% by weight of titanium dioxide (TiO2) abrasive, 1.8% by weight of cerium ammonium nitrate (CAN), and the amount of polyethylene oxide dispersant shown in Table 2. An A / B mixture was used for all formulations, and the particle dispersion (Pack A) was prepared to pH 2.85 and mixed with the oxidizing agent (Pack B) in a fixed ratio to obtain the final slurry composition for polishing silicon dioxide, titanium nitride, and boron polysilicon alloys. Before preparing Pack A, the titanium dioxide (TiO2) abrasive was treated with the polyethylene oxide dispersant to improve colloidal stability and the redispersibility of particles settled in the container. The final slurry had a pH of approximately 1 at the point of use.

[0149]

[0149] A patterned substrate containing a tetraethyl orthosilicate (i.e., silicon dioxide (Ox)) layer coated on a wafer, a boron-doped polysilicon (BSi) layer containing approximately 95% by weight of boron, or a titanium nitride (TiN) layer is polished using a Logitech 2 benchtop polishing machine with a downforce of 3 PSI (20.55 kPa) using SAESOL TM NexPlanar conditioned with a product commercially recognized as DS8051 (SAESOL Diamond Ind. Co. Ltd.) TM Polishing was performed using a U5890 pad (CMC Materials Inc.) with polishing compositions 2A to 2D as specified in Table 2. The Logitech polishing parameters were as follows: head speed = 86 rpm, platen speed = 93 rpm, total flow rate = 50 mL / min. All patterned substrates were polished for 60 seconds. The removal rate was calculated by measuring the film thickness using spectroscopic ellipsometry and subtracting the final thickness from the initial thickness. The results are shown in Table 2. The selectivity (Å / min) in Table 2 indicates the polishing rates of BSi and TiN relative to the polishing rate of TEOS. Table 2. Removal rate of abrasive composition as a function of dispersant concentration TIFF2026530512000003.tif72170

[0150]

[0150] As is evident from the results shown in Table 2, the low concentration of dispersant shown in polishing composition 2A of the present invention exhibited a high TiN removal rate but suppressed the removal of BSi. While we do not wish to be bound by any particular theory, it is thought that the titanium oxide polishing particles in polishing composition 2A of the present invention had a significantly larger particle size in pack A before being mixed with the oxidizing agent, which completely prevented the mechanical removal of BSi. Similarly, the high concentration of dispersant shown in polishing composition 2C of the present invention exhibited a high TiN removal rate but suppressed the removal of BSi.

[0151]

[0151] Polishing composition 2B of the present invention, containing 2% by weight of a dispersant, exhibited a high TiN and BSi removal rate while maintaining a low Ox removal rate. In contrast, comparative polishing composition 2D, having the same composition as polishing composition 2B of the present invention except for the absence of the oxidizing agent cerium ammonium nitrate (CAN), exhibited a low TiN and BSi removal rate. These results indicate that the combination of titanium dioxide (TiO2) abrasive and oxidizing agent preferably provides a high TiN and / or BSi removal rate while maintaining a low Ox removal rate. These results also indicate that the addition of a dispersant in amounts preferably of about 0.5% by weight or more and about 4% by weight or less helps to improve colloidal stability and the redispersibility of precipitated particles, preferably providing a high TiN and BSi removal rate while maintaining a low Ox removal rate.

[0152]

[0152] All references cited herein, including publications, patent applications, and patents, are incorporated herein by reference as if each reference were individually and specifically indicated and included herein in whole.

[0153]

[0153] In the context describing the present invention (in particular in the context of the claims), the use of the terms “a,” “an,” “the,” and “at least one,” and similar references, shall be interpreted as including both singular and plural forms unless otherwise indicated herein or unless clearly inconsistent with the context. When the term “at least one” is followed by an enumeration of one or more items (e.g., “at least one of A and B”), it shall be interpreted as meaning one item selected from the enumerated items (A or B), or a combination of two or more of the enumerated items (A and B), unless otherwise indicated herein or unless clearly inconsistent with the context. The terms “comprising,” “having,” “including,” and “containing” shall be interpreted as open-ended terms (i.e., “including, but not limited to”) unless otherwise indicated herein. The description of value ranges is intended merely as a concise way of referring individually to each individual value within that range, unless otherwise indicated herein, and each individual value is incorporated herein as if it were individually stated herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or unless it is clearly inconsistent with the context. Any examples or exemplary language provided herein (e.g., "etc.") are intended solely to better illustrate the invention and do not limit the scope of the invention unless otherwise specified. Nothing in this specification should be construed as indicating that elements not described in the claims are essential to the implementation of the invention.

[0154]

[0154] This specification describes preferred embodiments of the invention, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments will be apparent to those skilled in the art who have read the foregoing description. The inventors anticipate that those skilled in the art will adopt such variations as needed, and the inventors intend that the invention may be carried out in ways other than those specifically described herein. Accordingly, the invention includes all modifications and equivalents of the subject matter described in the claims, to the extent permitted by applicable law. Furthermore, unless otherwise indicated herein or unless clearly inconsistent with the context, any combination of the elements described above in all possible variations is encompassed by the invention.

Claims

1. A chemical mechanical abrasive composition, (a) Titanium oxide abrasives which are substantially pure rutile-type titanium oxide, (b) Oxidizing agents, and (c) water A chemical mechanical polishing composition containing the following, having a pH of approximately 7 or less.

2. The polishing composition according to claim 1, having a pH of approximately 6 or less.

3. The polishing composition according to claim 1, having a pH of approximately 5 or less.

4. The polishing composition according to claim 1, comprising approximately 0.001% to approximately 10% by weight of titanium oxide abrasive.

5. The polishing composition according to claim 1, comprising approximately 0.025% to approximately 5% by weight of titanium oxide abrasive.

6. The polishing composition according to claim 1, wherein the titanium oxide abrasive has an average particle size of about 10 nm to about 300 nm.

7. The polishing composition according to claim 1, wherein the titanium oxide abrasive has an average particle size of about 50 nm to about 150 nm.

8. The polishing composition according to claim 1, wherein the oxidizing agent is selected from oxone, cerium ammonium nitrate, peroxide, periodate, iodate, persulfate, chlorate, chromate, permanganate, bromate, perbromate, ironate, perrheniumate, perrutheniumate, and combinations thereof.

9. The polishing composition according to claim 1, wherein the oxidizing agent is selected from permanganate, cerium ammonium nitrate, and combinations thereof.

10. The polishing composition according to claim 9, wherein the oxidizing agent is cerium ammonium nitrate.

11. The polishing composition according to claim 9, wherein the oxidizing agent is potassium permanganate.

12. The polishing composition according to claim 1, comprising 1% to 20% by weight of an oxidizing agent.

13. The polishing composition according to claim 1, further comprising ferric ions.

14. The polishing composition according to claim 13, comprising approximately 0.01% to approximately 1% by weight of ferric ions.

15. The polishing composition according to claim 1, which is substantially free of ferric ions.

16. The polishing composition according to claim 1, further comprising about 1 mM to about 100 mM of an organic acid.

17. The polishing composition according to claim 16, wherein the organic acid is selected from maleic acid, citric acid, L-ascorbic acid, picolinic acid, malonic acid, and combinations thereof.

18. The abrasive composition according to claim 1, further comprising a buffering agent.

19. The polishing composition according to claim 18, wherein the buffering agent is selected from ammonium salts, alkali metal salts, alkali metal hydroxides, alkali metal carbonates, alkali metal bicarbonates, borates, amino acids, and combinations thereof.

20. A method for chemically and mechanically polishing a substrate, (i) To provide a substrate including a boron-doped polysilicon layer, (ii) To provide a polishing pad, (iii) To provide a chemical mechanical polishing composition, the chemical mechanical polishing composition is (a) Titanium oxide abrasive material containing approximately 0.001% to 10% by weight of substantially pure rutile-type titanium oxide, (b) Oxidizing agents, and (c) water To provide a chemical mechanical polishing composition containing and having a pH of approximately 7 or less, (iv) bringing the substrate into contact with the polishing pad and the chemical mechanical polishing composition, (v) To polish the substrate, the polishing pad and the chemical mechanical polishing composition are moved against the substrate, and at least a portion of the substrate is removed by friction. A method that includes this.

21. The method according to claim 20, wherein the titanium oxide abrasive has an average particle size of about 10 nm to about 300 nm.

22. The method according to claim 20, wherein the oxidizing agent is selected from oxone, cerium ammonium nitrate, peroxide, periodate, iodate, persulfate, chlorate, chromate, permanganate, bromate, perbromate, ironate, perrheniumate, perrutheniumate, or a combination thereof.

Images