Chemical mechanical polishing slurry composition and method for manufacturing semiconductor device

Abstract

The present invention provides cerium oxide particles for chemical mechanical polishing and a chemical mechanical polishing slurry composition containing the same. By combining the characteristic cerium oxide particles of the present invention with a cationic polymer and a nitride film polishing inhibitor, it is possible to provide a chemical mechanical polishing slurry composition that maximizes the silicon oxide film / nitride film selectivity ratio during shallow trench separation (STI) polishing while improving the oxide film polishing speed, and a method for manufacturing semiconductor devices utilizing the same.

Description

[Technical Field]

[0001] The present invention relates to a chemical mechanical polishing slurry composition containing cerium oxide particles and a method for manufacturing a semiconductor device. More specifically, the present invention relates to a method for producing a cerium oxide particle-containing slurry containing cerium oxide particles by a synthesis method different from that of existing cerium oxide particles. 3+ The present invention relates to a chemical mechanical polishing slurry composition that can provide a high oxide film removal rate at a low content despite its small particle size by increasing the ratio of , and in combination with this, can reduce the nitride film removal rate by using appropriate additive components to passivate fine patterns, and a method for manufacturing a semiconductor device using the same. [Background technology]

[0002] Recent advances in semiconductor device diversification and integration have been remarkable, leading to the use of ever-finer pattern formation technologies. As a result, the surface structures of semiconductor devices have become increasingly complex, making interlayer planarity in each process crucial for improving photolithography accuracy. Chemical mechanical polishing (CMP) is a commonly used planarization technique in semiconductor device fabrication. For example, it is widely used to remove excess insulating film for interlayer insulation, to planarize insulating films for shallow trench isolation (STI), which provides insulation between an interlayer dielectric (ILD) and a chip, and to form metal conductive films such as wiring, contact plugs, and via contacts.

[0003] In the CMP process, the polishing speed, the degree of planarization of the polished surface, and the degree of scratch generation are important, and these are determined by the CMP process conditions, the type of slurry, the type of polishing pad, etc. High-purity cerium oxide particles are used in cerium oxide slurries. Recently, in the manufacturing process of semiconductor devices, there has been a demand for even greater miniaturization of wiring, and polishing scratches that occur during polishing have become a problem.

[0004] Conventional cerium oxide slurries use particles with a size of 30 nm to 200 nm, and even if minute polishing scratches occur during polishing, they have not been considered a problem as long as they are smaller than the conventional wiring width. However, this is now considered a problem as the trend toward continuously miniaturizing wiring continues to be achieved. To address this problem, attempts have been made to reduce the average particle size of cerium oxide particles, but with existing particles, reducing the average particle size reduces the mechanical action, resulting in a problem of a decrease in the polishing rate.

[0005] Thus, even if one attempts to control the polishing rate and polishing scratches by controlling the average particle size of the cerium oxide particles, it is very difficult to achieve a target level of polishing scratches while maintaining the polishing rate.

[0006] In addition, in conventional chemical mechanical polishing slurry compositions, cerium oxide particles are 3+ Ce 4+ The ratio of Ce on the surface of cerium oxide was not optimized, and the average particle size was not optimized. 3+ At present, there is a need to conduct research into polishing slurries containing cerium oxide particles that exhibit a high oxide film removal rate despite their small particle size by increasing the ratio of cerium oxide particles.

[0007] Furthermore, for the CMP slurry containing cerium oxide particles under optimized conditions, there is currently a need for research into additive components for improvement in terms of oxide film polishing efficiency and oxide film / fine pattern polishing selectivity.

[0008] As described above, the inventors have developed cerium oxide particles of 10 nanometers or less in size, obtained by precipitation in a solution, which have a significantly improved oxide film polishing rate. By combining these optimized cerium oxide particles with additives, the inventors have developed a slurry composition that controls passivation of fine patterns on nitride films while at the same time significantly improving the silicon oxide film polishing rate, thereby completing the present invention. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made to solve the above-mentioned problems, and one embodiment of the present invention provides a slurry composition for chemical mechanical polishing.

[0010] Another embodiment of the present invention provides a method for manufacturing a semiconductor device.

[0011] The technical problems that the present invention aims to solve are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present invention pertains from the following description. [Means for solving the problem]

[0012] As a technical means for achieving the above technical object, one aspect of the present invention is to Provided is a slurry composition for chemical mechanical polishing, which comprises cerium oxide particles, a solvent, a cationic polymer, and a nitride film polishing inhibitor, and in an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0 wt %, has an average transmittance of 50% or more for light with wavelengths in the 450 to 800 nm range.

[0013] The cationic polymer may be characterized by increasing the polishing rate of the oxide film depending on its content.

[0014] The nitride film polishing inhibitor may be characterized by reducing the polishing rate of the nitride film depending on its content.

[0015] The content of the nitride film polishing inhibitor may be 0.001 to 1 wt % based on the total weight of the chemical mechanical polishing slurry composition.

[0016] The content of the cationic polymer may be 0.001 to 1 wt % based on the total weight of the chemical mechanical polishing slurry composition.

[0017] The cationic polymer may be polydiallyldimethylammonium chloride (Poly(DADMAC)), polydiethylenetriamine 2-(dimethylamino)ethyl methacrylate (Poly(DMAEM)), poly2-(dimethylamino)ethyl methacrylate (Poly(DMAEM)), polyacrylamide decamethylene diamine (Poly(Aam_DCDA)), poly(dimethylamine)-co-epichlorohydrin, poly(dimethylamine)-co-epichlorohydrin-co-ethylenediamine, or a combination thereof.

[0018] The nitride film polishing inhibitor may be characterized by being a sulfonic acid-based substance, a cationic surfactant, an amphoteric surfactant, or a combination thereof.

[0019] The nitride film polishing suppressor may be characterized as being at least one sulfonic acid-based material selected from the group consisting of polystyrene sulfonate (PSS), benzene sulfonate, C1-4 alkyl benzene sulfonate, di-C1-4 alkyl benzene sulfonate, C5-10 alkane sulfonate, and salts thereof.

[0020] The chemical mechanical polishing slurry composition may be characterized by containing 0.001 to 5% by weight of the cerium oxide particles relative to the total weight of the chemical mechanical polishing slurry composition.

[0021] The chemical mechanical polishing slurry composition may further comprise a pH adjuster, which may be one or more inorganic acids selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; one or more organic acids selected from the group consisting of acetic acid, citric acid, glutaric acid, glycolic acid, formic acid, lactic acid, malic acid, malonic acid, maleic acid, oxalic acid, phthalic acid, succinic acid, and tartaric acid; one or more amino acids selected from the group consisting of lysine, glycine, alanine, arginine, valine, leucine, isoleucine, methionine, cysteine, proline, histidine, phenylalanine, serine, tricine, tyrosine, aspartic acid, tryptophan, and aminobutyric acid; imidazole, alkylamines, alcoholamines, quaternary amine hydroxide, ammonia, or a combination thereof.

[0022] The composition may be characterized in that the pH is 2-10.

[0023] The chemical mechanical polishing slurry composition may be characterized by having a polishing rate for a silicon oxide film of 1,000 to 5,000 Å / min.

[0024] The chemical mechanical polishing slurry composition may be characterized by having a polishing selectivity of oxide film / nitride film of 200 to 2,000.

[0025] The secondary particle diameter of the cerium oxide particles measured by a dynamic light scattering (DLS) particle size distribution analyzer may be 1 to 20 nm.

[0026] The cerium oxide particles may have a primary particle diameter of 0.5 to 10 nm as measured by a transmission electron microscope (TEM).

[0027] In the analysis by X-ray photoelectron spectroscopy (XPS), the sum of the XPS peak areas showing the Ce-O bond energy on the surface of the cerium oxide particles is 100%. 3+The sum of the XPS peak areas showing the Ce—O bond energy may be 30% or more.

[0028] The cerium oxide particles may be produced by a step of precipitating the cerium oxide particles in a solution containing a raw material precursor at an acidic pH to obtain a dispersion of the particles.

[0029] Another aspect of the present invention is The chemical mechanical polishing slurry composition is used to polish a semiconductor device. [Effects of the Invention]

[0030] According to an embodiment of the present invention, the produced cerium oxide particles have Ce on the surface of the cerium oxide. 3+ The cerium oxide particles are characterized by their ability to achieve a high oxide removal rate even at low content when included in a chemical mechanical polishing slurry despite their small particle size, by increasing the ratio of cerium oxide particles. In addition, the addition of the cationic polymer disclosed in the present invention further increases the oxide polishing rate, and the oxide / nitride selectivity of the nitride polishing inhibitor is improved, enabling even finer patterns to be passivated. Considering the conventional common knowledge that the addition of a cationic polymer is usually done to sacrifice polishing rate in order to secure other properties, this is recognized as a unique effect of the present invention.

[0031] Furthermore, according to one embodiment of the present invention, it is possible to provide cerium oxide particles for a chemical mechanical polishing slurry composition and a slurry composition that can minimize surface defects on a wafer and maximize the removal rate of an oxide film, unlike the correlation between surface defects and the removal rate of an oxide film, which has conventionally been considered to be in a trade-off relationship.

[0032] The effects of the present invention are not limited to the effects described above, but should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the present invention or the claims. [Brief explanation of the drawings]

[0033] [Figure 1] 1 shows the mechanism of oxide film removal according to an embodiment of the present invention. [Figure 2a] 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. [Figure 2b] 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. [Figure 2c] 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. [Figure 2d] 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. [Figure 2e] 1A to 1C are cross-sectional views illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention. [Figure 2f] 1 illustrates a step-by-step process of chemical mechanical polishing and the structure of a chemical mechanical polishing (CMP) equipment according to another embodiment of the present invention. [Figure 2g] 1 illustrates a step-by-step process of chemical mechanical polishing and the structure of a chemical mechanical polishing (CMP) equipment according to another embodiment of the present invention. [Figure 3] 1 is a visual image of a dispersion in which conventional cerium oxide particles and cerium oxide particles according to an embodiment of the present invention are dispersed. [Figure 4] 1 is an electron transmission microscope (TEM) image of cerium oxide particles according to one embodiment of the present invention. [Figure 5] 1 shows a scanning electron microscope (SEM) image and a TEM image of conventional cerium oxide particles according to a comparative example. [Figure 6] 1 shows a TEM image of conventional cerium oxide particles as a comparative example. [Figure 7]1 shows the results of measuring the cerium oxide particles according to one embodiment of the present invention using a dynamic light scattering (DLS) particle size distribution analyzer, using a Zetasizer Ultra manufactured by Malvern Panalytical Ltd. in the UK. [Figure 8] 1 shows the results of an X-ray diffraction (XRD) analysis of cerium oxide particles according to an embodiment of the present invention. [Figure 9] 1 shows the results of analysis of cerium oxide particles according to an embodiment of the present invention and conventional cerium oxide particles of 60 nm class by X-ray photoelectron spectroscopy (XPS). [Figure 10] 1 shows the results of spectroscopic analysis by Fourier transform infrared (FT-IR) spectroscopy of a powder made of cerium oxide particles produced according to one embodiment of the present invention and a powder made of ordinary cerium hydroxide particles. [Figure 11] 1 shows the results of FT-IR spectroscopic analysis of a powder made of cerium oxide particles produced according to one embodiment of the present invention and a powder made of particles formed under other conditions. [Figure 12] 1 shows the results of measuring the light transmittance of slurries containing cerium oxide particles according to an example of the present invention and conventional cerium oxide particles according to Comparative Examples 1 to 4 using ultraviolet-visible (UV-Vis) spectroscopy. [Figure 13] 1 shows the effect of adding a cationic polymer according to an embodiment of the present invention on the polishing rate of an oxide film. [Figure 14] This shows that the adsorption amount to silicon oxide film (TEOS) is higher than that to polysilicon film, so when an appropriate amount is used, the polishing rate for TEOS is increased while the polishing rate for polysilicon film is reduced. [Figure 15] 1 is a scanned image of an oxide wafer before and after CMP using a CMP slurry composition containing cerium oxide particles according to an embodiment of the present invention and a CMP slurry composition containing cerium oxide particles of 60 nm size. [Figure 16] 1 is a scanned image of an oxide wafer after CMP using a CMP slurry composition containing cerium oxide particles according to an embodiment of the present invention and a CMP slurry composition containing cerium oxide particles of 60 nm size. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather as defined by the appended claims.

[0035] Furthermore, the terms used in this specification are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. Throughout the specification of the present invention, when a part "comprises" a certain element, this does not exclude other elements, and means that other elements may also be included, unless otherwise specified.

[0036] The term "monodisperse" as used herein means that when cerium oxide particles are dispersed in a slurry, aggregation into secondary particles is suppressed and the primary particle size is relatively maintained. This can mean that the secondary particle size (D50) measured by dynamic light scattering (DLS) is 3.0 times or less, 2.8 times or less, 2.5 times or less, 2.2 times or less to 2.0 times or less, or preferably 1.9 times or less of the primary particle size measured by TEM. Furthermore, when examining particle size distribution, etc., this does not exclude the inclusion of unavoidable impurities of relatively coarse sizes.

[0037] The term "transparent" as used in the present invention means that when cerium oxide particles are dispersed in a slurry, the slurry composition appears transparent when observed with the naked eye. More specifically, it means that the average transmittance to light in the visible light region is 50% or more, preferably 70% or more, and more preferably 80% or more. This may also mean that the cerium oxide particles of the present invention are prevented from agglomerating into secondary particles and relatively maintain their primary particle size.

[0038] Polishing compositions can be characterized by their polishing rate (i.e., removal rate) and their planarization efficiency. Polishing rate refers to the rate at which material is removed from the surface of a substrate, and is usually expressed in units of length (thickness) per unit time (e.g., angstroms (Å) per minute). Specifically, a polishing surface, such as a polishing pad, must first contact the "high points" of the surface and remove material to form a flat surface. A process that achieves a flat surface by removing less material is considered more efficient than a process that is forced to remove more material to achieve flatness.

[0039] The removal rate of silicon oxide patterns can often be rate-limiting for the dielectric polishing step in STI processes, so a high removal rate of silicon oxide patterns is desirable to increase device throughput. However, if the blanket removal rate is too high, excessive polishing of the oxide in the exposed trenches can lead to trench erosion and increase device defects.

[0040] The present invention will be described in detail below.

[0041] While the present invention may be embodied in many different forms, it is to be understood that the invention is not limited to the specific embodiments set forth herein.

[0042] Production Example 1. Production of cerium oxide particles The cerium oxide particles according to an embodiment of the present invention can be synthesized by chemical synthesis using a bottom-up method. In the embodiment of the present invention, the cerium oxide particles were prepared by any one of the following methods for preparing cerium oxide particles.

[0043] According to one embodiment of the present invention, approximately 2 to 4 kg of cerium nitrate was first added to a sufficient amount of deionized water and stirred. Nitric acid was added to the precursor solution to adjust the pH to 1.0 or less. Ammonia water was added to the resulting mixture and stirred until a precipitate formed. The pH of the stirred mixture was strongly acidic (2 or less), and it was confirmed that the product would precipitate quickly if left alone after stirring was completed. After removing the supernatant liquid from which the precipitate had been removed, a certain amount was added to deionized water to produce a pale yellow cerium oxide particle dispersion. The resulting dispersion was circulated and filtered using a membrane filter to obtain a transparent yellow cerium oxide dispersion.

[0044] According to another embodiment of the present invention, 150 g of cerium oxide or cerium hydroxide was dispersed in 3 kg of deionized water and stirred to a degree that prevented particles from settling. Nitric acid was added to the mixture until the pH reached 1.0 or less. The mixture was then placed in a milling machine filled with 0.05 mm zirconia beads and pulverized while circulating at 4,000 rpm. As milling proceeded, the opaque white cerium oxide dispersion was observed to gradually change into a transparent yellow cerium oxide dispersion. After milling was completed, the resulting transparent yellow cerium oxide dispersion was allowed to settle and then circulated and filtered using a membrane filter to obtain a pure, transparent yellow cerium oxide dispersion.

[0045] According to another embodiment of the present invention, approximately 2 to 4 kg of cerium ammonium nitrate was first added to a sufficient amount of ethanol and stirred. A basic imidazole solution was added to the precursor solution and stirred until a precipitate formed. The pH of the stirred mixture was strongly acidic (2 or less), and it was confirmed that the product quickly precipitated if left to stand after stirring was completed. After removing the supernatant liquid from which the precipitate had been removed, a certain amount was poured into deionized water to produce a cerium oxide particle dispersion. The produced dispersion was circulated and filtered using a membrane filter to obtain a transparent cerium oxide dispersion.

[0046] According to yet another embodiment of the present invention, first, 1.1 kg of cerium nitrate and 10 kg of deionized water were mixed in a reaction vessel to prepare a strongly acidic solution. The stirring speed of the reaction vessel was maintained at 200 rpm and at room temperature. A 1:1 mixture of 25% ammonia solution and deionized water was prepared and added to the reaction vessel until the pH reached 7.0. After stirring for 1 hour, a 1:1 mixture of 70% nitric acid and deionized water was added until the pH reached 1.0. The temperature of the reaction vessel was raised to 100°C and the reaction was carried out for 4 hours. During the reaction, pale purple large particles were dissociated, and yellow transparent cerium oxide nanoparticles were produced. The obtained particles were circulated using a membrane filter to remove impurities and obtain a pure cerium oxide nanoparticle dispersion.

[0047] Production Example 2: Production of CMP slurry containing cerium oxide particles The cerium oxide particles prepared in Preparation Example 1 were added to deionized water to adjust the abrasive concentration to 0.05 wt %, and triethanolamine was added to adjust the pH to 5.5 to prepare a CMP slurry.

[0048] As shown in FIG. 3, the slurry containing conventional ceria particles was visually observed to have high turbidity, whereas the slurry containing cerium oxide particles of the present invention was observed to be transparent, suggesting that it has monodisperse properties.

[0049] Comparative Examples 1 to 4: Preparation of conventional slurry compositions containing ceria particles Commercially available wet cerium oxide particles with average particle sizes of 10 nm, 30 nm, and 60 nm, respectively, and cerium oxide particles of the 10-20 nm class produced separately by a sintering method were prepared. These were then added to deionized water to adjust the abrasive concentration to 0.05% by weight, and ammonia was added as a pH adjuster to adjust the final pH to 5.5 to produce a CMP slurry.

[0050] Experimental Example 1. Analysis of cerium oxide particles using a scanning electron microscope (SEM) and a transmission electron microscope (TEM) The dispersion liquid of Production Example 1 according to one embodiment of the present invention was dried at approximately 80 to 90°C to prepare powdery cerium oxide particles (primary particles) (Sample A). Meanwhile, the cerium oxide particles used in producing the dispersion liquids of Comparative Examples 1 to 4 were prepared (Sample B1, Sample B2, Sample B3, and Sample B4, respectively). Images of each of the prepared samples were taken using a TEM measuring device.

[0051] FIG. 4 is a TEM image of cerium oxide particles according to one embodiment of the present invention.

[0052] Referring to Figure 4, it was confirmed that the particle diameter of the cerium oxide particles prepared according to one embodiment of the present invention was approximately 4 nm or less on average (repeated measurements showed 3.9 nm, 3.4 nm, and 2.9 nm, respectively) by TEM measurement. It was also confirmed that the average primary particle diameter of the cerium oxide particles according to one embodiment of the present invention was 4 nm or less. It was also confirmed that the cerium oxide particles had an average spherical particle shape. Spherical cerium oxide particles with a small particle diameter and a relatively uniform particle size distribution can have a wide specific surface area and are characterized by excellent dispersion stability and storage stability.

[0053] FIG. 5 shows SEM and TEM images of conventional cerium oxide particles according to a comparative example.

[0054] Referring to Figure 5, commercially available cerium oxide particles have particle sizes corresponding to their respective size classes, and even particles separately prepared by a calcination method are found to have primary particle sizes exceeding 10 nm on average. Comparing this with the average particle size of 4 nm or less measured by TEM for the cerium oxide particles according to one embodiment of the present invention shown in Figure 4, it can be seen that the cerium oxide particles of the conventional technology and the cerium oxide particles prepared by a conventional calcination method have much larger particle sizes. In contrast, the cerium oxide particles of the present invention have a smaller particle size (primary particle), and it can be expected that the smaller the cerium oxide particle size, the more defects such as scratches on the surface of the target film can be reduced.

[0055] 6 shows a TEM image of conventional cerium oxide particles as a comparative example. Referring to FIG. 6, it can be seen that conventional cerium oxide particles with a particle size of 10 nm or less include both edged particles and spherical particles, while conventional cerium oxide particles with a particle size of 30 nm or more consist of angular particles with edges. In contrast, as discussed above, the cerium oxide particles according to the present invention are generally spherical in shape. However, the cerium oxide particles of the present invention have such a spherical shape and a small particle size, allowing for a large number of particles to be included. Therefore, when polishing a silicon oxide film, the probability of surface defects occurring can be reduced and global flatness can be improved.

[0056] Experimental Example 2: Analysis of cerium oxide particles using a dynamic light scattering (DLS) particle size distribution analyzer A slurry composition of Preparation Example 2 according to an embodiment of the present invention and slurry compositions of Comparative Examples 1, 2, 3, and 4 were prepared as samples. Each of the prepared samples was analyzed using a dynamic light scattering (DLS) particle size distribution analyzer.

[0057] 7 shows the results of analysis of cerium oxide particles according to an embodiment of the present invention using a dynamic light scattering (DLS) particle size analyzer (Zetasizer Ultra, manufactured by Malvern Panalytical, UK). Table 1 below shows the D50 values ​​obtained by analysis of cerium oxide particles according to an embodiment of the present invention and comparative examples using the dynamic light scattering (DLS) particle size analyzer.

[0058] [Table 1]

[0059] 7 and Table 1, the cerium oxide particles according to the present invention have a secondary particle diameter D50 of approximately 5.78 nm, which is measured to be less than 10 nm. As measured in Experimental Example 1, this is approximately 148-199% of the primary particle diameter measured by TEM (see FIG. 4), confirming that there is almost no aggregation in the slurry, and the particles are monodispersed, resulting in almost no change in particle diameter.

[0060] In contrast, the D50 particle size of cerium oxide particles of the prior art, as measured using a dynamic light scattering (DLS) particle size analyzer, was confirmed to exceed 30 nm. Even in the case of cerium oxide particles of the 10 nm class, the secondary particle size D50 value measured using a dynamic light scattering (DLS) particle size analyzer was approximately 336% of the primary particle size measured using TEM. This indicates that the cerium oxide particles of the prior art have a much larger secondary particle size, which confirms that severe aggregation has occurred.

[0061] In particular, in the case of cerium oxide particles of 10 nanometers or less produced by supercritical hydrothermal synthesis or wet synthesis under basic conditions, it can be confirmed that secondary particles are formed to be larger than the primary particle size, as predicted by the inventors.

[0062] Furthermore, it was confirmed that the monodispersity of cerium oxide particles in the slurry is maintained even when the slurry contains a nitride film polishing inhibitor and a cationic polymer as additives (Example 2). Therefore, it was confirmed that the cationic polymer and nitride film polishing inhibitor claimed in the present invention are suitable for use in combination with cerium oxide particles according to one embodiment of the present invention.

[0063] Therefore, it can be seen that the cerium oxide particles according to an embodiment of the present invention have less agglomeration in the slurry than the cerium oxide particles according to the conventional technique of the comparative example, and can be dispersed in the slurry in a more monodispersed form.

[0064] Experimental Example 3: Analysis of cerium oxide particles by X-ray diffraction (XRD) The dispersion liquid of Production Example 1 according to one embodiment of the present invention was dried at approximately 80 to 90°C to prepare powder-shaped cerium oxide particles (primary particles) (Sample A). Sample A was analyzed using an X-ray diffractometer (Ultima IV manufactured by Rigaku Corporation). The XRD conditions were set to CuKα (λ=1.5418 Å), 40 kV, and 40 mA.

[0065] FIG. 8 shows the results of analysis of cerium oxide particles according to one embodiment of the present invention by X-ray diffraction (XRD).

[0066] As a result of analyzing Sample A by X-ray diffraction (XRD), an XRD spectrum (X axis: 2θ (°), Y axis: intensity) with the shape shown in FIG. 8 was derived. The crystallite size calculated from the spectrum was 3.25 nm. This was approximately the same level as the TEM analysis result in Experimental Example 1, and it was therefore possible to confirm that the particles of the present invention have single-crystal properties.

[0067] Experimental Example 4: Analysis of cerium oxide particles by X-ray photoelectron spectroscopy (XPS) 9 shows the results of analysis of cerium oxide particles according to an embodiment of the present invention and conventional cerium oxide particles of 60 nm size by X-ray photoelectron spectroscopy (XPS). X-ray photoelectron spectroscopy (XPS) shows that Ce is 3+ The peaks appearing at 900.2 to 902.2 eV, 896.4 to 898.4 eV, 885.3 to 887.3 eV, and 880.1 to 882.1 eV, which indicate the Ce-O bond energy, were measured and analyzed using XPS fitting to determine the atomic percentage of Ce in the cerium oxide particles. 3+ and Ce 4+ The content of can be measured. Table 2 below shows the analysis results of cerium oxide particles according to the embodiments of the present invention by X-ray photoelectron spectroscopy (XPS).

[0068] [Table 2]

[0069] From the results of the X-ray photoelectron spectroscopy (XPS) analysis, Ce was found to be 3+ As a result of calculating the content of Ce 3+ It can be seen that the content of Ce in cerium oxide particles is 30% or more. 3+ Since these are reactive sites, it can be inferred that this will increase the polishing rate. Table 3 shows the comparative data with conventional cerium oxide particles obtained by the above method.

[0070] [Table 3]

[0071] In the case of the cerium oxide particles according to one embodiment of the present invention, as is clear from Table 3 above, Ce 3+ The content of Ce in conventional 60 nm-class cerium oxide particles is about 36.9 atomic %. 3+The content of Ce is less than 14 atomic %, which is higher than that of cerium oxide particles produced by hydrothermal synthesis under supercritical or subcritical conditions (10 nm class), which is about 16.8% as known from previous literature. 3+ It can be confirmed that the surface contains Ce. 3+ When the content is at a high level as in the examples of the present invention, the polishing rate for silicon-containing substrates can be increased by the chemical polishing mechanism of forming Si—O—Ce between silica and cerium.

[0072] Experimental Example 5. Confirmation of the formation of cerium oxide particles using Fourier transform infrared (FT-IR) spectroscopy analysis 10 shows the results of spectroscopic analysis by Fourier transform infrared (FT-IR) spectroscopy of a powder made of cerium oxide particles produced according to one embodiment of the present invention and a powder made of ordinary cerium hydroxide particles. The dispersion liquid of Production Example 1 according to one embodiment of the present invention was dried at approximately 80 to 90°C to prepare powder-shaped cerium oxide particles (primary particles), and then a spectrum was obtained using a Fourier transform infrared (FT-IR) spectrophotometer. The analysis range was 600 to 4100 cm. -1 The graph was plotted by repeating the scan one or more times (wave number in FT-IR spectrum (cm -1 ) is ±10cm -1 (The error may be within the range of 1 / 2000.)

[0073] As a result of analyzing the FT-IR spectrum of FIG. 10, the 3000 cm -1 ~3600cm -1 The transmittance of infrared light in the range of 720cm is approximately 92-93%. -1 ~770cm -1 It can be confirmed that the infrared transmittance in the range of 3000 cm is approximately 93 to 95%. -1 ~3600cm -1 Infrared transmittance within the range of 75-90%, 720cm -1 ~770cm -1In comparison, the transmittance of infrared rays in the range of 3000 cm is 97-99% for the cerium oxide particles prepared according to an embodiment of the present invention. -1 ~3600cm -1 In the range of 720cm, the bond by the OH group of the cerium hydroxide particles appears weaker than that of ordinary cerium hydroxide particles. -1 ~770cm -1 It can be seen that a peak due to Ce-O stretching is formed within the range of 0.05 to 0.05. Therefore, this result indicates that the cerium compound prepared according to one embodiment of the present invention is cerium oxide.

[0074] As a comparative example, among cerium oxide particles synthesized by a wet method similar to one embodiment of the present invention, when the synthesis is performed under basic conditions, cerium hydroxide is first formed and then converted to cerium oxide in a post-process. According to the experimental results shown in Figure 11, when FT-IR was measured immediately after synthesis of particles synthesized under basic pH conditions, the 3000 cm peak, which indicates cerium hydroxide, was observed. -1 ~3600cm -1 range and 720cm -1 ~770cm -1 Since the peaks in this range are the same as the main peaks of cerium hydroxide in FIG. 10, it is difficult to say that the sample contains only cerium oxide.

[0075] Experimental Example 6: Measurement of the light transmittance of a slurry containing cerium oxide particles A slurry composition (Sample A) was prepared in the same manner as in Preparation Example 2, except that the weight ratio of cerium oxide particles in the CMP slurry was 1 wt %. Meanwhile, slurry compositions (Sample B1, Sample B2, Sample B3, and Sample B4, respectively) were prepared in the same manner as in Comparative Examples 1, 2, 3, and 4, except that the weight ratio of cerium oxide particles in the CMP slurry was 1 wt %. The transmittance of each sample to light in the range of 200 to 1100 nm was measured using an ultraviolet-visible spectrophotometer (UV-Vis spectrophotometer) (manufactured by JASCO).

[0076] Figure 12 shows the results of measuring the light transmittance of cerium oxide particles according to one embodiment of the present invention and slurries containing conventional cerium oxide particles from Comparative Examples 1 to 4 using ultraviolet-visible spectroscopy.

[0077] The cerium oxide particles according to the present invention and the comparative example were added to deionized water to adjust the abrasive concentration to 1.0 wt% to prepare CMP slurries, and their transmittance was analyzed. The optical spectrum was measured in the range of 200 to 1,100 nm using a UV-Vis spectrophotometer (manufactured by JASCO).

[0078] Using the aforementioned UV-Vis analysis graph, the transmittance (%) of samples A, A2, and B1-B4 at wavelengths of 500nm, 600nm, and 700nm are summarized in Table 4 below.

[0079] [Table 4]

[0080] As shown in Figure 11 and Table 2, in the case of the slurry containing cerium oxide particles of the present invention, it can be confirmed that the average light transmittance for light with wavelengths of 450 to 800 nm is 50% or more. Furthermore, it was confirmed that the light transmittance for light with a wavelength of approximately 500 nm is 90% or more, and the light transmittance for light with wavelengths of approximately 600 nm and 700 nm is 95% or more.

[0081] In contrast, the transmittance of slurries containing conventional cerium oxide particles from Comparative Examples 1 to 4 (10-nm, 30-nm, and 60-nm conventional cerium oxide particles and calcined ceria particles) was measured. Comparative Example 4 (calcined ceria particles) exhibited a transmittance of approximately 0%, while the transmittance of the slurry of Comparative Example 1, which contained commercially available 10-nm conventional cerium oxide particles, was on average less than 80%, indicating a transmittance of less than 50% at a wavelength of 500 nm. Comparative Examples 2 and 3 exhibited coarse primary particle diameters of 30 nm and 60 nm, respectively, and coarse secondary particle diameters compared to the examples of the present invention (i.e., due to greater cohesion within the slurry), resulting in transmittances of less than 20% in the visible light range.

[0082] In contrast, the cerium oxide particles according to one embodiment of the present invention were found to exhibit a transmittance of 90% or more in the visible light region, which means that the primary particle diameter of the cerium oxide particles of the present invention is small and aggregation into secondary particles occurs less frequently than with cerium oxide particles of the prior art. Generally, when the secondary particles exceed 20 nm, the opacity of the slurry composition can be observed with the naked eye, and it is well known that the transmittance in the visible light region is less than 80%.

[0083] According to the slurry composition of the present invention, it can be confirmed that the high light transmittance is the result of the uniform distribution of particles due to the increased dispersion stability when the primary particle size of the cerium oxide particles is small and the tendency to agglomerate into secondary particles is low. As the number of particles contacting the wafer increases, the polishing rate of the oxide film is extremely fast, and since the particles themselves are very small, it can be easily predicted that the probability of defects such as scratches occurring on the surface will be low when a polishing target film is polished using a slurry composition containing the particles.

[0084] Furthermore, even if the additives, a cationic polymer and a nitride film polishing inhibitor, are included, it can be confirmed that the transmittance characteristics of the present invention are maintained at the same level. However, considering that incorrect selection of additives may impair the monodispersity characteristics of cerium oxide particles in the slurry according to one aspect of the present invention, the cationic polymer and nitride film polishing inhibitor selected in the present invention suggest that the required characteristics can be met without impairing the basic particle characteristics in the slurry.

[0085] Experimental Example 7: Comparison of the polishing rate of oxide film of cerium oxide particles Slurry compositions of Preparation Examples 2 and 3 according to an embodiment of the present invention and a comparative example slurry composition were prepared as samples.

[0086] The oxide film wafers were polished using the sample using a polishing machine (Reflexion® LK CMP, manufactured by Applied Materials Japan, Inc.). Specifically, a PE-TEOS silicon oxide wafer (300 mm PE-TEOS wafer) was placed on a platen, and the surface of the wafer was brought into contact with a polishing pad (IC1010, manufactured by Dow Chemical). The sample slurry composition was then supplied at a rate of 200 mL / min, and the polishing process was performed while rotating the platen and the polishing pad. The platen and head rotation speeds were 67 rpm and 65 rpm, respectively, the polishing pressure was 2 psi, and the polishing time was 60 seconds. The thickness of the silicon oxide thin film on the wafer was measured using an ST5000 (Spectra Thick 5000ST, manufactured by K-MAC, Korea). The results are shown in Table 5 below.

[0087] [Table 5]

[0088] As shown in Table 5 above, it was confirmed that the removal rate of silicon oxide film when using the slurry composition of the example was at least about six times faster than that of the slurry composition of the comparative example. This is because the cerium oxide particles contained in the slurry composition of the example have a small particle size, and the number of particles that are effective in polishing is large compared to the content, and the Ce on the surface is removed. 3+ This is presumably because the content (molar ratio and / or weight ratio) of increases the chemical reactivity with the surface of the silicon oxide film.

[0089] Furthermore, it was found that the slurry composition of Preparation Example 3, which further contained a cationic polymer and a nitride film polishing inhibitor, exhibited a further improvement in oxide film polishing rate compared to the slurry composition of Preparation Example 2, which contained no additives. This indicates that when the cationic polymer according to one embodiment of the present invention is combined with cerium oxide particles according to one embodiment of the present invention, the cationic polymer is positioned between the cerium oxide particles according to one embodiment of the present invention, further maximizing their unique monodispersity and maximizing the number and area of ​​particles in contact with the silicon oxide film. This increases the oxide film polishing rate up to a certain content range. Beyond the certain range, the dishing control agent itself may partially block or impede contact between the cerium oxide particles and the oxide film, thereby decreasing the oxide film polishing rate. This distinctive behavior of oxide film polishing rate depending on the content of the cationic polymer is quite contrary to the observed decrease in oxide film polishing rate from the initial content when the cationic polymer described in this invention is used in combination with conventional cerium oxide particles. Such characteristics are shown in simplified form in FIG.

[0090] This characteristic is even more noteworthy when compared with the fact that when a cationic polymer according to one embodiment of the present invention is added to a slurry composition using ordinary ceria particles of 60 nanometers or less produced according to conventional techniques, the polishing rate of the oxide film is actually reduced.

[0091] Experimental Example 8: Evaluation of defects in cerium oxide particles 15 and 16 are scanned images of an oxide wafer before and after CMP using a CMP slurry composition containing cerium oxide particles according to one embodiment of the present invention and a CMP slurry composition containing cerium oxide particles with a particle size of 60 nm.

[0092] The surface analysis of the oxide wafer was carried out by a full wafer scan method using an AIT-XP device.

[0093] 15 and 16 , analysis of the surface of an oxide wafer subjected to CMP using a CMP slurry composition containing cerium oxide particles according to an embodiment of the present invention before and after CMP revealed that the number of defects before CMP was 6 and the number of defects after CMP was 1, confirming that the number of defects on the surface of the oxide wafer was reduced after CMP using a CMP slurry composition containing cerium oxide particles according to an embodiment of the present invention, and that no scratches were generated on the surface of the wafer during the CMP process. In contrast, analysis of the surface of an oxide wafer subjected to CMP using a CMP slurry composition containing cerium oxide particles according to a conventional technique before and after CMP revealed that the number of defects increased from 34 before CMP to 64 after CMP, confirming that the cerium oxide particles according to the conventional technique caused scratches on the surface of the wafer. This suggests that the particle size of the cerium oxide particles according to an embodiment of the present invention is smaller than that of the conventional technique, thereby significantly reducing the probability of defects on the surface of the oxide wafer being polished. Furthermore, in the case of the cerium oxide particles according to one embodiment of the present invention, they are monodispersed in the slurry and are themselves very small particles, so it is recognized that it is fully predictable that defects will be minimized even if additive substances are contained.

[0094] Experimental Example 9. Analysis of the polishing selectivity ratio of oxide / nitride films with the addition of additives. Cerium oxide particles prepared according to an embodiment of the present invention and conventional commercially available 60 nm cerium oxide particles were added to deionized water, the pH was adjusted to 5.8, and then cationic polymers were added as shown in Table 6 below. Under the polishing conditions of Experimental Example 7, the polishing rates (Å / min) of oxide films and nitride films (Å / min) were measured.

[0095] [Table 6]

[0096] Referring to Table 6 above, it can be seen that when a cationic polymer and nitride film passivation modifier according to one aspect of the present invention are included, the polishing rate of the nitride film during the STI process is significantly reduced (30-80%) compared to when no additives are included. This is noteworthy because it is an effect that can be obtained without impairing the properties of the particles in the slurry according to one aspect of the present invention. In the case of the cationic polymer according to one aspect of the present invention, as shown in Figure 14, the amount adsorbed to the silicon oxide film (TEOS) is higher than that of the nitride film, so when an appropriate amount is used, the polishing rate of the TEOS is increased, while the polishing rate of the silicon nitride film decreases. Furthermore, it can be seen that the cationic polymer according to one aspect of the present invention basically has the characteristic of lowering the polishing rate of the nitride film when added.

[0097] (Mode for carrying out the invention) A first aspect of the present invention is Provided is a slurry composition for chemical mechanical polishing, which comprises cerium oxide particles, a solvent, a cationic polymer, and a nitride film polishing inhibitor, and in an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0 wt %, has an average transmittance of 50% or more for light with wavelengths in the 450 to 800 nm range.

[0098] The chemical mechanical polishing slurry composition according to the first aspect of the present invention will be described in detail below.

[0099] Fig. 1 shows the mechanism of oxide film removal according to one embodiment of the present invention. As shown in Fig. 1, Ce is deposited on the surface of cerium oxide particles. 3+ If the ions are not activated, they cannot react smoothly with SiO2.

[0100] In one embodiment of the present invention, the inclusion of the cationic polymer and the nitride film polishing inhibitor may significantly reduce the polishing rate of the nitride film. This is a major technical feature of the chemical mechanical polishing slurry composition of the present invention compared to the prior art, and will be described in detail below. In particular, this feature will be described in detail below because it provides a unique effect in combination with the cerium oxide particles specific to the present invention, as described below.

[0101] In one embodiment of the present invention, the cationic polymer can serve several purposes in the chemical mechanical polishing slurry composition of the present invention. First, it can reduce the occurrence of dishing and erosion that can occur during the STI process. Second, it can act as a stabilizer for the slurry composition and as a pH buffer, ensuring particle dispersibility and dispersion stability. The cationic polymer of the present invention can also function as a polishing accelerator for oxide films. In conventional polishing slurries, cationic polymers are added to increase dispersion stability or to protect field oxide films during step removal. However, to achieve these properties, the oxide film polishing rate must be partially sacrificed. In contrast, the cationic polymer added to the polishing slurry of the present invention not only increases dispersion stability, but also increases the overall oxide film polishing rate as the amount of cationic polymer added increases.

[0102] As will be described later, the cerium oxide particles according to one embodiment of the present invention are obtained by a wet method at an acidic pH and are obtained in the form of a dispersion. A solvent may be added to the cerium oxide particles to immediately prepare a slurry, or the particles may have a monodispersed form of ultrafine cerium oxide nanoparticles without a separate re-dispersion process. The surface Ce 3+The content of is also maintained at a high level, and the particles exhibit a very high level of oxide film polishing speed when manufacturing a slurry composition for chemical mechanical polishing. As described above, even if various additives used in the conventional art are added to cerium oxide particles according to one aspect of the present invention, which have unique properties, the performance intended in the conventional art is difficult to achieve, as revealed by the inventors' research. Furthermore, from the perspective of an ordinary engineer using nanoparticles, in a composition containing nanoparticles, it is necessary to find and combine substances suitable for specific nanoparticles to achieve the desired properties or performance. In the case of a slurry composition according to one aspect of the present invention, a nitride film polishing inhibitor may be further added to minimize the nitride film polishing speed without impairing (or even increasing) the excellent oxide film polishing speed performance of the cerium oxide particles.

[0103] In one embodiment of the present invention, the principle by which the cerium oxide particles, cationic polymer, and nitride film polishing inhibitor substance exhibit their effects is as follows. In the case of cerium oxide particles according to the embodiment of the present invention, they have the characteristic of being monodispersible in the slurry without any particular dispersion process. In the case of the cationic polymer, as a result of being positioned between the monodisperse cerium oxide particles, the cerium oxide particles can uniformly and smoothly contact the silicon oxide film, thereby maximizing the polishing speed. In the case of the nitride film polishing inhibitor, it can hinder the cerium oxide particles from contacting the nitride film, thereby minimizing the polishing speed of the nitride film. By using an appropriate content, it is also possible to proceed without hindering the polishing speed of the silicon oxide film.

[0104] In one embodiment of the present invention, the content of the cationic polymer may be 0.001 wt % or more, 0.002 wt % or more, 0.003 wt % or more, 0.004 wt % or more, or 0.005 wt % or more, based on the total weight of the slurry composition for chemical mechanical polishing, or 1 wt % or less, 0.5 wt % or less, 0.1 wt % or less, 0.05 wt % or less, 0.03 wt % or less, or 0.01 wt % or less. If the content of the cationic polymer is less than 0.001% by weight of the chemical mechanical polishing slurry composition, the content is too small to adequately function as an oxide film polishing accelerator and therefore does not affect the oxide film polishing rate. Conversely, if the content of the cationic polymer is more than 1% by weight of the chemical mechanical polishing slurry composition, the added cationic polymer may interfere with the cerium oxide polishing process and thereby reduce the oxide film polishing rate, or may become an impurity in the slurry composition.

[0105] In one embodiment of the present invention, the content of the nitride film polishing inhibitor may be 0.001 wt % or more, 0.002 wt % or more, 0.003 wt % or more, 0.004 wt % or more, or 0.005 wt % or more, based on the total weight of the slurry composition for chemical mechanical polishing, or may be 1 wt % or less, 0.5 wt % or less, 0.1 wt % or less, 0.05 wt % or less, 0.03 wt % or less, or 0.01 wt % or less. If the content of the nitride film polishing inhibitor is less than 0.001% based on the total weight of the chemical mechanical polishing slurry composition, the content is too small to fully function as a nitride film polishing inhibitor and therefore has no effect on reducing the nitride film polishing rate. Conversely, if the content of the passivation control agent is more than 1% based on the total weight of the chemical mechanical polishing slurry composition, the added nitride film polishing inhibitor may interfere with the cerium oxide polishing process and instead reduce the oxide film polishing rate, or may become an impurity in the slurry composition.

[0106] In one aspect of the present invention, the cationic polymer may be a polymer or copolymer containing an amine group or an ammonium group. For example, the cationic polymer may be characterized by being polydiallyldimethylammonium chloride (Poly(DADMAC)), polydiethylenetriamine 2-(dimethylamino)ethyl methacrylate (Poly(DMAEM)), poly 2-(dimethylamino)ethyl methacrylate (Poly(DMAEM)), polyacrylamide decamethylene diamine (Poly(Aam_DCDA)), poly(dimethylamine)-co-epichlorohydrin, poly(dimethylamine)-co-epichlorohydrin-co-ethylenediamine) or a combination thereof.

[0107] In one embodiment of the present invention, the nitride film polishing inhibitor may be characterized by being a sulfonic acid-based substance selected from the group consisting of polystyrene sulfonate (PSS), benzene sulfonate, C1-4 alkylbenzene sulfonate, di-C1-4 alkylbenzene sulfonate, C5-10 alkane sulfonate, and salts thereof.

[0108] The present invention relates to a slurry composition for chemical mechanical polishing, and is characterized in that the slurry composition contains cerium oxide particles having excellent dispersion stability and a particularly excellent polishing rate for silicon oxide films.

[0109] In one embodiment of the present invention, the cerium oxide particles contained as abrasive particles in the slurry may have a positive zeta potential, preferably 1 to 80 mV, 5 to 60 mV, or 10 to 50 mV in a pH range of 2 to 8. When the cerium oxide particles have a positive zeta potential, the surface of the silicon oxide film exhibits a negative polarity, and as a result, the polishing efficiency can be increased due to the attractive force between the cerium oxide particles and the surface of the silicon oxide film.

[0110] In one aspect of the present invention, the cerium oxide particles have a lower hardness than silica particles or alumina particles, but due to a chemical polishing mechanism in which Si-O-Ce bonds are formed between silica and cerium, they have an extremely high polishing rate for silicon-containing surfaces such as glass and semiconductor substrates, making them advantageous for polishing semiconductor substrates.

[0111] In one embodiment of the present invention, the particle size of the cerium oxide particles in the slurry can be measured by dynamic light scattering (DLS) analysis (secondary particles). The dynamic light scattering analysis can be performed using analytical equipment well known to those skilled in the art, preferably a particle size analyzer manufactured by Anton Paar or a Zetasizer Ultra manufactured by Malvern Panalytical, UK. However, these are merely non-limiting examples and the present invention is not limited thereto. The secondary particles described above are formed by aggregation of the primary particles described below in the slurry. It can be easily inferred that the larger the surface area of ​​the particles, the wider the area over which attractive forces act, and therefore aggregation should proceed smoothly. Furthermore, as the pH range in the solution passes through the isoelectric point, at which the zeta potential of the particles becomes 0, aggregation into secondary particles occurs. In the case of cerium oxide particles, as disclosed in various sections on prior art, the isoelectric point pH is about 7. In the case of a wet process, if particle synthesis is completed under basic conditions, the isoelectric point will inevitably be passed while adjusting the pH to produce a slurry. As a result, it may be difficult to obtain monodispersity in the slurry, as with the particles of one embodiment of the present invention.

[0112] In one embodiment of the present invention, the particle diameter of the cerium oxide particles measured by a dynamic light scattering (DLS) particle size analyzer may be 1 to 30 nm. In another embodiment of the present invention, the particle diameter may be 29 nm or less, 27 nm or less, 25 nm or less, 23 nm or less, 22 nm or less, 20.8 nm or less, 20.5 nm or less, 20.2 nm or less, 20 nm or less, 19.8 nm or less, 19.5 nm or less, 19.2 nm or less, 18 nm or less, 17 nm or less, or 15 nm or less, or 1.2 nm or more, 1.4 nm or more, 1.5 nm or more, 1.8 nm or more, 2 nm or more, 3 nm or more, or 4 nm or more. If the secondary particle diameter exceeds the above range, this indicates that active aggregation of primary particles occurs in the slurry composition, making it difficult to recognize the slurry as monodispersed. If the secondary particle diameter is less than the above range, the polishing rate for the target film may be excessively inhibited, resulting in reduced polishing efficiency.

[0113] In one embodiment of the present invention, the particle diameter of the cerium oxide particles can be measured by an electron transmission microscope (TEM) (primary particles). In one embodiment of the present invention, the particle diameter of the cerium oxide particles measured by an electron transmission microscope (TEM) may be 11 nm or less. In another embodiment, the particle diameter of the cerium oxide particles, as measured by electron transmission microscopy (TEM), may be 10.8 nm or less, 10.5 nm or less, 10.2 nm or less, 10 nm or less, 9.5 nm or less, 9.0 nm or less, 8.5 nm or less, 8.0 nm or less, 7.5 nm or less, 7.0 nm or less, 6.5 nm or less, 6.0 nm or less, 5.5 nm or less, 5.0 nm or less, 4.5 nm or less, or 4.0 nm or less, or may be 0.3 nm or more, 0.5 nm or more, 0.7 nm or more, 1.0 nm or more, 1.1 nm or more, 1.2 nm or more, 1.3 nm or more, 1.4 nm or more, 1.5 nm or more, 1.6 nm or more, 1.7 nm or more, 1.8 nm or more, 1.9 nm or more, 2.0 nm or more, 2.1 nm or more, 2.2 nm or more, 2.3 nm or more, or 2.4 nm or more. If the particle size of the cerium oxide particles is less than 0.3 nm, the crystallinity may be reduced, which may excessively inhibit the polishing rate for the target film and reduce the polishing efficiency, whereas if the particle size of the cerium oxide particles is more than 11 nm, there is a risk of a large amount of surface defects such as scratches occurring.In one aspect of the present invention, the average particle size of the cerium oxide particles measured by the electron transmission microscope (TEM) may be 0.5 to 10 nm, preferably 1 to 10 nm, and more preferably 2 to 9 nm.

[0114] From the viewpoint of characterizing the cerium oxide particles according to one aspect of the present invention, the cerium oxide particles may be characterized by satisfying the following formula 1, where a is the particle diameter of the cerium oxide particles measured with a dynamic light scattering (DLS) particle size analyzer and b is the particle diameter of the cerium oxide particles measured with an electron transmission microscope (TEM):

[0115] [Formula 1]

number

[0116] Such a characteristic should be an indicator of low agglomeration when the cerium oxide particles of the present invention are dispersed in a slurry. If the coefficient b exceeds 2.2, this means that agglomeration occurs actively in the slurry, which should mean that the particle size becomes coarse, making it difficult to suppress surface defects on the wafer during polishing.

[0117] In one embodiment of the present invention, the particle size of the cerium oxide particles can be measured by analysis using X-ray diffraction (XRD) (primary particles). In one embodiment of the present invention, the particle size of the cerium oxide particles measured by analysis using X-ray diffraction (XRD) may be 11 nm or less. In another embodiment, the particle size of the cerium oxide particles, as measured by X-ray diffraction (XRD) analysis, may be 10.8 nm or less, 10.5 nm or less, 10.2 nm or less, 10 nm or less, 9.5 nm or less, 9.0 nm or less, 8.5 nm or less, 8.0 nm or less, 7.5 nm or less, 7.0 nm or less, 6.5 nm or less, 6.0 nm or less, 5.5 nm or less, 5.0 nm or less, 4.5 nm or less, or 4.0 nm or less, or may be 0.3 nm or more, 0.5 nm or more, 0.7 nm or more, 1.0 nm or more, 1.1 nm or more, 1.2 nm or more, 1.3 nm or more, 1.4 nm or more, 1.5 nm or more, 1.6 nm or more, 1.7 nm or more, 1.8 nm or more, 1.9 nm or more, 2.0 nm or more, 2.1 nm or more, 2.2 nm or more, 2.3 nm or more, or 2.4 nm or more. If the particle size of the cerium oxide particles is less than 0.3 nm, the crystallinity may be reduced, the polishing rate for the target film may be excessively inhibited, and the polishing efficiency may be reduced, whereas if the particle size of the cerium oxide particles is more than 11 nm, there may be a risk of a large amount of surface defects such as scratches.In one aspect of the present invention, the average particle size of the cerium oxide particles measured by the analysis using X-ray diffraction (XRD) may be 0.5 to 10 nm, preferably 1 to 10 nm, and more preferably 2 to 9 nm.

[0118] In one embodiment of the present invention, Ce on the surface of the cerium oxide particles 3+ The content of Ce on the surface of the cerium oxide abrasive particles can be analyzed using X-ray photoelectron spectroscopy (XPS), for example, using a theta probe base system manufactured by Thermo Fisher Scientific. 3+ The content can be calculated by the following general formula 1.

[0119] [General formula 1] Ce 3+ Content (%) = (Ce 3+ (Peak area of) / [(Ce 3+ (Peak area of) + (Ce 4+ (Peak area)

[0120] In one embodiment, the surface of the cerium oxide particles is found to contain Ce upon analysis by X-ray photoelectron spectroscopy (XPS). 3+ The cerium oxide particles may be characterized in that XPS peaks showing Ce-O bond energies appear at 900.2 to 902.2 eV, 896.4 to 898.4 eV, 885.3 to 887.3 eV, and 880.1 to 882.1 eV. Specifically, when analyzed by X-ray photoelectron spectroscopy (XPS), the surfaces of the cerium oxide particles are 3+ The XPS peaks showing the Ce—O bond energy may appear at a first peak of 900.2 to 902.2 eV, a second peak of 896.4 to 898.4 eV, a third peak of 885.3 to 887.3 eV, and a fourth peak of 880.1 to 882.1 eV.

[0121] In one embodiment of the present invention, the area of ​​the first peak may be 3% or more, or 4% or more, the areas of the second peak and the fourth peak may be 5% or more, 7% or more, or 10% or more, respectively, of the total XPS peak area, and the area of ​​the third peak may be 4% or more, 5% or more, or 6% or more.

[0122] In one embodiment of the present invention, in an analysis by X-ray photoelectron spectroscopy (XPS), the ratio of Ce to the total area of ​​XPS peaks indicating Ce-O bond energy on the surface of the cerium oxide particles is 3+ In another embodiment of the present invention, the ratio of the sum of the XPS peak areas showing the Ce-O bond energy on the surface of the cerium oxide particle to the sum of the XPS peak areas showing the Ce-O bond energy on the surface of the cerium oxide particle may be 0.29 to 0.70. 3+ to the sum of XPS peak areas indicating Ce—O bond energies may be 0.18 or more, 0.19 or more, 0.192 or more, 0.195 or more, 0.198 or more, 0.20 or more, 0.202 or more, 0.205 or more, 0.208 or more, 0.21 or more, 0.22 or more, 0.24 or more, 0.25 or more, 0.27 or more, 0.28 or more, 0.30 or more, 0.32 or more, or 0.35 or more. Alternatively, it may be 0.90 or less, 0.88 or less, 0.85 or less, 0.83 or less, 0.80 or less, 0.77 or less, 0.75 or less, 0.72 or less, 0.71 or less, 0.705 or less, 0.70 or less, 0.695 or less, 0.69 or less, 0.68 or less, 0.67 or less, 0.66 or less, 0.65 or less, 0.64 or less, 0.63 or less, 0.62 or less, 0.61 or less, or 0.60 or less. 3+ As a result, it will be difficult to expect a sufficient increase in the polishing rate of the oxide film, and if the range is exceeded, it may be difficult to interpret the particles as existing as cerium oxide particles when considering the oxidation number.

[0123] That is, in one embodiment of the present invention, when analyzed by X-ray photoelectron spectroscopy (XPS), Ce is not present on the surface of the cerium oxide particles for chemical mechanical polishing. 3+or 35 atomic % or more, or alternatively, may be characterized by comprising 90 atomic % or less, 88 atomic % or less, 85 atomic % or less, 83 atomic % or less, 80 atomic % or less, 77 atomic % or less, 75 atomic % or less, 72 atomic % or less, or 70 atomic % or less.

[0124] In the case of cerium oxide particles according to one embodiment of the present invention, Ce on the surface of the particles 3+ This is due to the fact that the particle synthesis process in a liquid state through a wet process is carried out under acidic conditions in accordance with one embodiment of the present invention. In the case of a cerium precursor material containing trivalent cerium, the trivalent state of cerium is generally maintained at an acidic pH. However, in the preparation method according to one embodiment of the present invention, there is no transition to a basic pH throughout the entire particle synthesis process, resulting in a high trivalent cerium content on the surface of the synthesized particles. This trivalent cerium content characteristic on the surface of the cerium oxide particles is due to the formation and maintenance of surface defects during the preparation process, and is therefore considered to be a characteristic independent of technical characteristics such as the primary or secondary particle size described above. As described above, the cerium oxide particles according to one embodiment of the present invention have a high trivalent cerium content on the particle surface. 3+ The content of Ce becomes higher, and thus the surface 3+ When the content is relatively high, the polishing rate of the oxide film can be improved.

[0125] In one embodiment of the present invention, when Fourier-transform infrared (FT-IR) spectroscopy is performed on the powder of cerium oxide particles, a spectrum determined by the FT-IR spectroscopy shows a peak at 3000 cm -1 ~3600cm -1 The powder of cerium oxide particles may have an infrared transmittance of 90% or more, or 100% or less, 97% or less, or 95% or less, within the range of 720 cm. -1~770cm -1 The infrared transmittance of the powder within this range may be 96% or less, and may be 85% or more, 88% or more, more preferably 90% or more, and even more preferably 92% or more. -1 ~3600cm -1 The fact that the infrared transmittance in the range of 720 cm in the FT-IR spectrum of the powder made of cerium oxide particles according to one embodiment of the present invention is within this range may mean that the bond by the OH group is relatively weak, which is different from the FT-IR spectrum of the powder made of cerium hydroxide particles. -1 ~770cm -1 The presence of a peak indicating infrared transmittance within this range may indicate the presence of Ce-O stretching within this range, which may indicate that the particles prepared according to an embodiment of the present invention exhibit the characteristics of cerium oxide particles. In particular, among methods for preparing cerium oxide particles, wet methods, when synthesized under basic conditions, require a conversion process to cerium oxide, such as a separate heat treatment or prolonged oxygen exposure. Therefore, if FT-IR is measured before this subsequent process and immediately after the particle synthesis process, a peak related to cerium hydroxide may be detected. In contrast, the cerium oxide particles according to one embodiment of the present invention do not undergo a process of first forming cerium hydroxide and then converting it to cerium oxide, so only a peak related to cerium oxide is detectable even when measured immediately after synthesis.

[0126] In one embodiment of the present invention, the cerium oxide primary particles may have one or more shapes selected from the group consisting of spherical, cubic, tetragonal, orthorhombic, rhombohedral, monoclinic, hexagonal, triclinic, and cuboctahedron shapes, and are preferably spherical particles.

[0127] In one embodiment of the present invention, the cerium oxide particles can be produced by a method of growing particles using chemical synthesis, preferably a bottom-up method. Methods that can be used to synthesize the cerium oxide particles include a sol-gel method, a supercritical reaction, a hydrothermal reaction, and a co-precipitation method, but the present invention is not limited thereto. The bottom-up method is a type of chemical synthesis that has recently been attracting attention, in which atomic or molecular starting materials are grown into nanometer-sized particles using a chemical reaction.

[0128] In one aspect of the present invention, the polishing composition comprises wet cerium oxide particles. The wet cerium oxide particles may be any suitable wet cerium oxide particles. For example, the wet cerium oxide particles may be precipitated cerium oxide particles, including colloidal cerium oxide particles, or condensation-polymerized cerium oxide particles.

[0129] Also, in one aspect of the present invention, the wet cerium oxide particles preferably have defects on the particle surface. Without wishing to be bound by any particular theory, milling of cerium oxide particles can introduce defects on the cerium oxide particle surface, and such defects can affect the performance of the cerium oxide particles in a chemical mechanical polishing composition. In particular, the cerium oxide particles can be fractured when milled, which can expose less favorable surface states. This process, known as relaxation, allows atoms around the surface of the cerium oxide particles, which have limited ability to reconstruct and return to more favorable states, to form defects on the particle surface.

[0130] In one aspect of the present invention, when generating secondary particles of an abrasive, each solvent has its own dielectric constant. The dielectric constant of the solvent changes the surface energy and surface charge during nucleation and crystal growth during powder synthesis, affecting the aggregation and growth of nuclei, which in turn affects the size and shape of the powder. The dielectric constant of the solvent and the surface potential (zeta potential) of the particles dispersed in the solvent are proportional to each other. If the zeta potential is low, the surface repulsive force between the microparticles or between the nuclei generated by the reaction is small, resulting in an unstable state and the possibility of rapid aggregation between the microparticles or between the nuclei. In this case, the magnitude of the surface repulsive force is approximately the same between the microparticles and between the nuclei, allowing them to aggregate to a uniform size. The secondary particles thus aggregated grow into relatively large particles through a strong aggregation reaction between the primary microparticles or the nuclei or a particle coalescence process such as Ostwald ripening, depending on reaction conditions such as temperature and concentration.

[0131] When cerium oxide is used as an abrasive, its high reactivity with silicon oxide forms Si-O-Ce chemical bonds, which polishes the silicon oxide film as if it were peeling off silicon oxide nodules from the surface of the silicon oxide film, unlike mechanical polishing, which only removes the hydrated layer formed on the surface. Furthermore, the cerium oxide powder according to the present invention has low strength due to its small particle size, which provides excellent global flatness during polishing and also solves the problem of micro-scratches formed by large particles.

[0132] Hereinafter, a chemical mechanical polishing slurry composition containing the cerium oxide particles and a nitride film polishing inhibitor according to one embodiment of the present invention will be described.

[0133] In one aspect of the present invention, an aqueous dispersion containing 1.0 wt% of cerium oxide particles may have an average light transmittance of 50% or more, or 60% or more, preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more, for light having a wavelength of 450 to 800 nm. In another aspect of the present invention, the average light transmittance may be 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, or 80% or more, for light having a wavelength of 500 nm. Alternatively, the average light transmittance may be 75% or more, 80% or more, 85% or more, or 90% or more, for light having a wavelength of 600 nm. Alternatively, the average light transmittance may be 87% or more, 90% or more, 93% or more, or 95% or more, for light having a wavelength of 700 nm. The fact that the transmittance of the slurry composition satisfies the above range may mean that the cerium oxide particles according to one embodiment of the present invention have a small primary particle size and exhibit even less aggregation into secondary particles than conventional ceria particles. This reduced agglomeration leads to high dispersion stability, uniform particle distribution, and an increased number of particles contacting the wafer, resulting in a significantly faster oxide film polishing rate. Furthermore, the particles themselves are small, which can be easily predicted to reduce the likelihood of surface defects such as scratches occurring when polishing a target film using a slurry composition containing these particles. That is, for cerium oxide particles with a primary particle size of 10 nm or less, the higher the transmittance in the visible light range, the faster the silicon oxide film polishing rate. Furthermore, these transmittance characteristics can be maintained even when the additives, the cationic polymer and nitride film polishing inhibitor, are further included.

[0134] In one embodiment of the present invention, the chemical mechanical polishing slurry composition may contain 5 wt% or less of the cerium oxide particles based on the total weight of the chemical mechanical polishing slurry composition. In another embodiment of the present invention, the chemical mechanical polishing slurry composition may contain 4 wt% or less, 3 wt% or less, 2 wt% or less, 1.5 wt% or less, 1 wt% or less, 0.8 wt% or less, 0.5 wt% or less, 0.4 wt% or less, 0.3 wt% or less, 0.2 wt% or less, less than 0.2 wt%, 0.19 wt% or less, 0.15 wt% or less, 0.12 wt% or less, 0.10 wt% or less, 0.09 wt% or less, or 0.07 wt% or less, based on the total weight of the chemical mechanical polishing slurry composition. The chemical mechanical polishing slurry composition of the present invention may be characterized in that, even if a slurry having the same polishing rate is used, the cerium oxide particles may be added in a smaller amount relative to the total weight of the chemical mechanical polishing slurry composition, and still achieve high oxide film polishing efficiency.

[0135] In one embodiment of the present invention, the pH of the composition may be 2 to 10. In one embodiment of the present invention, the chemical mechanical polishing slurry composition may include one or more acidic or basic pH adjusters and buffers that can adjust the pH in consideration of the final pH of the composition, the polishing rate, the polishing selectivity, etc. As the pH adjuster for adjusting the pH, a pH adjuster that can adjust the pH without affecting the properties of the chemical mechanical polishing slurry composition can be used. In one embodiment of the present invention, the pH adjuster may be an acidic pH adjuster or a basic pH adjuster to achieve an appropriate pH.

[0136] In one embodiment of the present invention, examples of the pH adjuster include one or more inorganic acids selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; one or more organic acids selected from the group consisting of acetic acid, citric acid, glutaric acid, glycolic acid, formic acid, lactic acid, malic acid, malonic acid, maleic acid, oxalic acid, phthalic acid, succinic acid, and tartaric acid; one or more amino acids selected from the group consisting of lysine, glycine, alanine, arginine, valine, leucine, isoleucine, methionine, cysteine, proline, histidine, phenylalanine, serine, tricine, tyrosine, aspartic acid, tryptophan, and aminobutyric acid; imidazole, alkylamines, alcoholamines, quaternary amine hydroxides, ammonia, or combinations thereof. In particular, the pH adjuster may be triethanolamine, tetramethylammonium hydroxide (TMAH or TMAOH), or tetraethylammonium hydroxide (TEAH or TEA-OH). Examples of the pH adjuster include at least one selected from the group consisting of ammonium methyl propanol (AMP), tetramethyl ammonium hydroxide (TMAH), potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, triethanolamine, tromethamine, and nicotinamide. Preferably, the pH adjuster is triethanolamine or aminobutyric acid.

[0137] In one embodiment of the present invention, the solvent may be any solvent commonly used in chemical mechanical polishing slurry compositions, such as deionized water, but the present invention is not limited thereto. Preferably, ultrapure water is used. The content of the solvent may be the remaining content of the chemical mechanical polishing slurry composition, excluding the content of the cerium oxide particles and other additional additives. In one embodiment of the present invention, the solvent may include water (e.g., deionized water) as an aqueous carrier and one or more water-miscible organic solvents. Examples of usable organic solvents include alcohols such as propenyl alcohol, isopropyl alcohol, ethanol, 1-propanol, methanol, and 1-hexanol; aldehydes such as acetylaldehyde; ketones such as acetone, diacetone alcohol, and methyl ethyl ketone; esters such as ethyl formate, propyl formate, ethyl acetate, methyl acetate, methyl lactate, butyl lactate, and ethyl lactate; sulfoxides such as ethers including dimethyl sulfoxide (DMSO), tetrahydrofuran, dioxane, and diglyme; amides such as N,N-dimethylformamide, dimethylimidazole lidinone, and N-methylpyrrolidone; polyhydric alcohols and derivatives thereof such as ethylene glycol, glycerol, diethylene glycol, and diethylene glycol monomethyl ether; and nitrogen-containing organic compounds such as acetonitrile, amylamine, isopropylamine, and dimethylamine.

[0138] In one embodiment of the present invention, the polishing composition optionally further comprises one or more other additives, such as rheology modifiers, including viscosity enhancers and coagulants (e.g., polymeric rheology modifiers such as urethane polymers), biocides (e.g., KATHON™ LX), and the like.

[0139] In one aspect of the present invention, the chemical mechanical polishing slurry composition is characterized by excellent dispersion stability and, in particular, a high polishing rate for silicon oxide films.

[0140] In one aspect of the present invention, the chemical mechanical polishing slurry composition may be characterized by having a silicon oxide film polishing rate of 1,000 Å / min or more, preferably 2,000 Å / min or more, more preferably 3,000 Å / min or more. Basically, the higher the oxide film polishing rate, the better. The upper limit is not particularly limited, but the chemical mechanical polishing slurry composition may be characterized by having a silicon oxide film polishing rate of 10,000 Å / min or less, 9,000 Å / min or less, 8,000 Å / min or less, 7,000 Å / min or less, 6,000 Å / min or less, or 5,000 Å / min or less. In particular, in the case of the chemical mechanical polishing slurry composition using cerium oxide particles according to one aspect of the present invention, the particle size is small even in the low cerium oxide particle content range, so that the number of particles contained is larger than that of conventional slurry compositions containing cerium oxide particles, and the surface Ce is easily removed. 3+ The high content of cerium increases the number of Si-O-Ce bonds, which can dramatically increase the polishing rate of silicon oxide films.

[0141] In one embodiment of the present application, the chemical mechanical polishing slurry composition may have an oxide / nitride polishing selectivity of 50 or more, 100 or more, 150 or more, or 200 or more, and may be characterized as having an oxide / nitride polishing selectivity of 3,000 or less, 2,000 or less, 1,500 or less, 1,000 or less, 900 or less, or 800 or less. In the case of oxide / nitride selectivity, it cannot be excluded that a selectivity of 3,000 or more can be achieved by appropriately adjusting the content of the cationic polymer.

[0142] A second aspect of the present invention is The chemical mechanical polishing slurry composition is used to polish a semiconductor device.

[0143] Detailed explanations of parts that overlap with the first aspect of the present invention have been omitted, but the contents explained for the first aspect of the present invention are similarly applicable to the second aspect even if the explanation is omitted.

[0144] The method for manufacturing a semiconductor device according to the second aspect of the present invention will now be described in detail.

[0145] First, regarding the shallow trench isolation (STI) routine process, among the processes for planarizing the insulating film, photolithography, etching, and polishing can be classified into commonly applied basic processes.

[0146] The process begins with the photolithography process, the first step in separating the elements. The photolithography process is carried out using auxiliary equipment called a track and an exposure tool that exposes the wafer to light to transfer the circuit pattern (mask) onto the wafer. First, a photoresist is applied. Because the photoresist has high viscosity, it is applied thinly onto the insulating film while the wafer is rotated. The applied photoresist must be uniform in height to achieve the appropriate exposure depth. If the exposure depth is insufficient during exposure, photoresist residue will remain during development, preventing the underlying film (insulating layer) from being properly removed during the subsequent etching process. After exposure, the wafer is transferred back to the track equipment for the development process, which removes the exposed areas.

[0147] The second step, STI etching, removes the insulating layer (oxide layer + nitride layer) and part of the substrate directly below the developed area (the area where the photoresist film was removed). This etching process can be either dry or wet. Dry etching typically uses plasma to dig down. Compared to wet etching (liquid), dry etching only digs down without etching the side walls (anisotropic etching), potentially preserving the trench shape. To avoid overetching, the etching endpoint must be accurately calculated before proceeding. Residue remains after etching, which can be removed.

[0148] After etching the trench shape, the photosensitive layer is no longer useful and may be removed by ashing. The ashing process may be preferably performed using plasma, which allows for a more accurate ashing process. The shape of the semiconductor device after the ashing process is completed is shown in FIG. 2a.

[0149] A method for manufacturing a semiconductor device according to an aspect of the present invention may include simultaneously polishing a silicon oxide film, a silicon nitride film, and a polysilicon film using the chemical mechanical polishing slurry composition.

[0150] 2a to 2e are cross-sectional views illustrating a method for manufacturing a semiconductor device according to one embodiment of the present invention.

[0151] Referring to FIG. 2a, a trench 13 may be formed in an upper film 11 on a lower film 10. As an example, the upper film 11 may be formed on the lower film 10, and a nitride film (polishing stop film) 12 may be formed on the upper film 11. The lower film 10 may include any material film. For example, the lower film 10 may be an insulating film, a conductive film, a semiconductor film, or a semiconductor wafer (substrate). The upper film 11 may include an insulating film (oxide film), a conductive film, a semiconductor film, or a combination thereof.

[0152] When the upper film 11 includes a plurality of stacked insulating films, the insulating films may be of the same type or different types. For example, the upper film 11 may include a silicon oxide film and a silicon nitride film that are alternately and repeatedly stacked. The upper film 11 may further include a semiconductor film and a lower insulating film below the silicon oxide film and the silicon nitride film. For example, the lower insulating film may be disposed below the semiconductor film.

[0153] The nitride film (polishing stop film) 12 may be formed to a relatively large thickness (e.g., 100 Å to 4,000 Å) by depositing, for example, silicon nitride (e.g., SiN), polysilicon, metal nitride (e.g., TiN), or metal. The trench 13 may be formed by an etching process or a drilling process. The trench 13 may have a depth that penetrates the nitride film (polishing stop film) 12 and the upper film 11 to reach the lower film 10. For example, the trench 13 may have a depth sufficient to expose the lower film 10.

[0154] Referring to FIG. 2b, a double oxide layer may be formed in STI. First, before filling the trench 13 with an insulating material, a thin liner oxide layer is deposited as the first insulating layer 14 by diffusion. This is believed to ensure that the second insulating layer, which is deposited using chemical vapor deposition (CVD) in the subsequent step, is successfully formed on the silicon substrate. According to another aspect of the present invention, this layer can also serve to prevent damage from high-energy plasma when filling the trench 13 using high-density plasma CVD (HDPCVD). According to another aspect of the present invention, the first insulating layer (liner oxide layer) can be formed as a thin film similar to a gate oxide layer by introducing oxygen gas into a diffusion furnace and heating it to a high temperature. According to another aspect of the present invention, a nitride layer may be used instead of the oxide layer.

[0155] Referring to FIG. 2c, a first insulating film 14 and a second insulating film 15 filling the trench 13 may be formed by depositing multiple insulating materials. The first insulating film 14 and the second insulating film 15 may have different densities and deposition rates. According to an embodiment of the present invention, the first insulating film 14 may be formed by depositing a high-density insulating material, and the second insulating film 15 may be formed by depositing a low-density insulating material. As an example, the first insulating film 14 may be formed by depositing and patterning a high-density plasma (HDP) oxide. The first insulating film 14 may be formed in a shape extending along the inner surface of the trench 13. For example, the first insulating film 14 may have a U-shape or a pipe shape that opens upward.

[0156] Because the first insulating film 14 has a high density, voids are unlikely to occur within the first insulating film 14, which can eliminate or significantly reduce the occurrence of cracks due to voids during a subsequent heat treatment process. The second insulating film 15 may be formed, for example, by depositing tetraethylorthosilicate (TEOS) oxide to a thickness sufficient to cover the polishing stop film 12 while filling the trench 13 with the first insulating film 14. The second insulating film 15 can be formed at a deposition rate even higher than that of the first insulating film 14. The high deposition rate of the second insulating film 15 allows the trench 13 to be filled with the second insulating film 15 relatively quickly.

[0157] According to another aspect of the present invention, although not shown, the second insulating film 15 may be partially removed to leave the second insulating film 15 on the trench 13. For example, the second insulating film 15 may be selectively removed by a photolithography process and an etching process to define or open a specific region, such as a cell memory region of a semiconductor device. This allows a part or all of the second insulating film 15 on the polishing stop film 12 to be removed, and the second insulating film 15 may remain on the trench 13. The process of opening the specific region is performed selectively, but is not essential.

[0158] Referring to FIG. 2d, a planarization process may be performed on the second insulating film 15. For example, the second insulating film 15 may be planarized by a chemical mechanical polishing (CMP) process. The chemical mechanical polishing process may be continued until the nitride film (polishing stop film) 12 is exposed. The chemical mechanical polishing process may be performed after the formation of the second insulating film 15 in FIG. 2b. In this case, the surface on the nitride film (polishing stop film) 12 is relatively flat, or even if not flat, its unevenness is not severe, so the chemical mechanical polishing process can be easily performed.

[0159] Then, referring to FIG. 2e, the nitride film may be removed to form an STI region. The nitride film serves to protect the upper film 11 from being affected by the first insulating film 14. The upper film 11 must be handled carefully because it may become a gate oxide film, which must be thin and highly reliable. When removing the nitride film using an etching method (wet etching), the wafer may be immersed in a chemical solution to etch only the nitride film without etching the oxide film. For this purpose, a solution with a high selectivity (etching ratio) to the nitride film may be used. In another embodiment of the present invention, the nitride film may also be removed using CMP. In this case, it is not necessary to further etch the nitride film, but because physical damage to the oxide film may occur, it is preferable to chemically treat the nitride film using an etching method to protect the oxide film.

[0160] According to another aspect of the present invention, the chemical mechanical polishing (CMP) process removes all of the first insulating film 14 and the second insulating film 15 on the nitride film (polishing stop film) 12 after filling the gap, thereby isolating the active region and the field region. The process may be roughly divided into three steps as shown in FIG. 2f.

[0161] In the first step, local planarization is performed by bulk CMP of the second insulating film 15 on a platen. In the second step, the second insulating film 15, whose step height has been reduced, is cleaned or polished on the platen, and polishing is stopped when the nitride film (polishing stop layer) 12 is exposed. At this time, end point detection (EPD) is used to detect when the different film material is exposed. In the third step, any residue of the second insulating film 15 that may remain on the nitride film (polishing stop layer) 12 on the platen is removed, and the nitride and oxide film materials may be polished and targeted.

[0162] 2g shows the structure of a chemical mechanical polishing (CMP) equipment according to one embodiment of the present invention. This equipment is characterized by having three platens, and as described above, it may be configured so that STI CMP is carried out in stages by passing through platens 1, 2, and 3 in that order. After polishing, the wafer moves to the cleaning section where cleaning is completed, and the process is completed.

[0163] In addition, in the method for manufacturing a semiconductor device according to one aspect of the present invention, the method for simultaneously polishing a silicon oxide film, a silicon nitride film, and a polysilicon film using the chemical mechanical polishing slurry composition may be any polishing method and condition that is conventionally used, and is not particularly limited in the present invention.

[0164] The slurry composition for chemical mechanical polishing according to one aspect of the present invention has high dispersion stability, and the Ce on the surface of the cerium oxide particles contained in the slurry composition is 3+ Because of its high content, the polishing rate for silicon-containing substrates can be increased by the chemical polishing mechanism of forming Si-O-Ce between silica and cerium, and even under conditions containing a low ceria content, it can be effectively used to remove silicon oxide films, in particular, from the surface of semiconductor devices in CMP processes.

[0165] A third aspect of the present invention is The present invention provides a semiconductor device comprising: a substrate; and a trench formed on the substrate and filled with an insulating material, the trench being formed by polishing at least one film selected from the group consisting of a silicon oxide film, a silicon nitride film, and a polysilicon film using a chemical mechanical polishing slurry composition, the chemical mechanical polishing slurry composition comprising cerium oxide particles, a solvent, a cationic polymer, and a nitride film polishing suppressor.

[0166] Detailed explanations of parts that overlap with the first and second aspects of the present invention have been omitted, but the contents explained for the first and second aspects of the present invention are similarly applicable to the third aspect even if the explanation is omitted.

[0167] A fourth aspect of the present invention is providing a feedstock precursor; grinding or precipitating cerium oxide particles in a solution containing a raw material precursor to obtain a dispersion of cerium oxide particles for chemical mechanical polishing; The present invention provides a method for producing cerium oxide particles, comprising:

[0168] Detailed explanations of parts that overlap with the first to third aspects of the present invention have been omitted, but the contents explained for the first to third aspects of the present invention are similarly applicable to the fourth aspect even if the explanation is omitted.

[0169] In one aspect of the present invention, the method for producing cerium oxide particles may include a step of preparing a raw material precursor, which may be any precursor material capable of producing the cerium oxide particles as a product, without limitation.

[0170] In one aspect of the present invention, the method for producing cerium oxide particles may include a step of obtaining a dispersion of cerium oxide particles for chemical mechanical polishing by grinding or precipitating cerium oxide particles in a solution containing a raw material precursor. The step of grinding the cerium oxide particles in the solution containing the raw material precursor may be, for example, grinding using a milling process, and the grinding method can be determined without limitation within the scope of common technical knowledge of ordinary engineers. In the case of the step of precipitating cerium oxide particles in a solution containing a raw material precursor to obtain a dispersion of cerium oxide particles, the step of removing a supernatant or filtering the cerium oxide particles may further be included.

[0171] In particular, in one embodiment of the present invention, the entire particle synthesis process can be carried out at room temperature without going through a basic pH, which has the advantage of realizing an efficient manufacturing process from an energy perspective while still exhibiting the above-mentioned particle characteristics.

[0172] The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments should be understood to be merely illustrative in all respects and not limiting. For example, each component described as being single may be implemented in a distributed form, and similarly, each component described as being distributed may be implemented in a combined form.

[0173] The scope of the present invention is expressed by the claims described below, and any modifications or alterations derived from the meaning and scope of the claims, as well as the concept of equivalents, should be interpreted as being included within the scope of the present invention. [Industrial Applicability]

[0174] According to an embodiment of the present invention, the produced cerium oxide particles have Ce on the surface of the cerium oxide. 3+ The cerium oxide particles are characterized by being able to achieve a high oxide film removal rate even at a low content when included in a chemical mechanical polishing slurry despite their small particle size by increasing the ratio of the additive. When this is combined with the configuration of the surface treatment agent disclosed in the present invention, the zeta potential of the surface of the cerium oxide particles can be converted to a negative value, thereby expanding the range of applications to include polishing of nitride films, and other applications. This provides an improved effect compared to when no additive is added, and therefore has industrial applicability.

Claims

1. Cerium oxide particles; a solvent; a cationic polymer; a nitride film polishing inhibitor; Including, A slurry composition for chemical mechanical polishing, characterized in that, in an aqueous dispersion in which the content of the cerium oxide particles is adjusted to 1.0 wt %, the average transmittance for light with wavelengths in the range of 450 to 800 nm is 50% or more.

2. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the polishing rate of the oxide film increases depending on the content of the cationic polymer.

3. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the nitride film polishing inhibitor reduces the polishing rate of the nitride film depending on the content thereof.

4. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the content of the nitride film polishing inhibitor is 0.001 to 1 wt % based on the total weight of the chemical mechanical polishing slurry composition.

5. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the content of the cationic polymer is 0.001 to 1 wt % based on the total weight of the chemical mechanical polishing slurry composition.

6. The cationic polymers include polydiallyldimethylammonium chloride (Poly(DADMAC)), polydiethylenetriamine 2-(dimethylamino)ethyl methacrylate (Poly(DMAEM)), poly2-(dimethylamino)ethyl methacrylate (Poly(DMAEM)), polyacrylamide decamethylenediamine (Poly(DMAEM)), and poly(dimethylamino)ethyl methacrylate (Poly(DMAEM)).

2. The chemical mechanical polishing slurry composition of claim 1, wherein the compound is selected from the group consisting of poly(dimethylamine), poly(Aam_DCDA), poly(dimethylamine)-co-epichlorohydrin, poly(dimethylamine)-co-epichlorohydrin-co-ethylenediamine, and combinations thereof.

7. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the nitride film polishing inhibitor is a sulfonic acid-based material, a cationic surfactant, an amphoteric surfactant, or a combination thereof.

8. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the nitride film polishing inhibitor is at least one sulfonic acid-based material selected from the group consisting of polystyrene sulfonate (PSS), benzene sulfonate, C1-4 alkyl benzene sulfonate, di-C1-4 alkyl benzene sulfonate, C5-10 alkane sulfonate, and salts thereof.

9. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the cerium oxide particles are contained in an amount of 0.001 to 5 wt % based on the total weight of the chemical mechanical polishing slurry composition.

10. The chemical mechanical polishing slurry composition further comprises a pH adjuster, The pH adjuster may be at least one inorganic acid selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; at least one organic acid selected from the group consisting of acetic acid, citric acid, glutaric acid, glycolic acid, formic acid, lactic acid, malic acid, malonic acid, maleic acid, oxalic acid, phthalic acid, succinic acid, and tartaric acid; one or more amino acids selected from the group consisting of lysine, glycine, alanine, arginine, valine, leucine, isoleucine, methionine, cysteine, proline, histidine, phenylalanine, serine, tricine, tyrosine, aspartic acid, tryptophan, and aminobutyric acid; 2. The chemical mechanical polishing slurry composition of claim 1, wherein the compound is imidazole, alkylamines, alcoholamine, quaternary amine hydroxide, ammonia, or a combination thereof.

11. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the pH of the composition is 2 to 10.

12. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the chemical mechanical polishing slurry composition has a polishing rate of silicon oxide film of 1,000 to 5,000 Å / min.

13. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the chemical mechanical polishing slurry composition has an oxide / nitride polishing selectivity of 200 to 2,000.

14. 2. The chemical mechanical polishing slurry composition according to claim 1, wherein the secondary particle diameter of the cerium oxide particles measured by a dynamic light scattering (DLS) particle size distribution analyzer is 1 to 20 nm.

15. 2. The chemical mechanical polishing slurry composition according to claim 1, wherein the cerium oxide particles have a primary particle diameter of 0.5 to 10 nm as measured by a transmission electron microscope (TEM).

16. In the analysis by X-ray photoelectron spectroscopy (XPS), the total area of ​​the XPS peaks showing the Ce—O bond energy on the surface of the cerium oxide particles is 100%. ３＋ 2. The chemical mechanical polishing slurry composition according to claim 1, wherein the sum of the XPS peak areas showing the Ce—O bond energy is 30% or more.

17. 2. The chemical mechanical polishing slurry composition of claim 1, wherein the cerium oxide particles are prepared by precipitating the cerium oxide particles in a solution containing a raw material precursor at an acidic pH to obtain a particle dispersion.

18. 10. A method for manufacturing a semiconductor device, comprising the step of polishing with the chemical mechanical polishing slurry composition of claim 1.

Images