Cerium oxide particles, a chemical mechanical polishing slurry composition containing the same, and a method for manufacturing semiconductor devices.

Abstract

This invention provides cerium oxide particles for chemical and mechanical polishing and a chemical and mechanical polishing slurry composition containing the same. [Solution] On the surface of the cerium oxide particles, Ce 3+ and Ce 4+ When using a chemical mechanical polishing slurry composition containing Ce on a cerium oxide surface, 3+ By increasing the ratio of this compound, it is possible to achieve a high oxide film removal rate and oxide film polishing selectivity even in a low content range, despite the fine particle size.

Description

[Technical Field]

[0001] The present invention relates to cerium oxide particles for chemical mechanical polishing, a chemical mechanical polishing slurry composition containing the same, and a method for manufacturing semiconductor devices. More specifically, unlike existing cerium oxide particles, the present invention relates to the synthesis of Ce on the surface of cerium oxide. 3+ This invention relates to a chemical mechanical polishing slurry composition that has a high oxide film removal rate despite its low particle size, and a method for manufacturing a semiconductor device using the same, by increasing the ratio of the same. [Background technology]

[0002] As semiconductor devices become more diverse and highly integrated, even finer pattern formation technologies are being used, which makes the surface structure of semiconductor devices more complex. Interlayer flatness in each process is therefore a crucial factor in improving the accuracy of photolithography. Chemical mechanical polishing (CMP) is used as such a planarization technique in the manufacturing of semiconductor devices. For example, it is widely used as a process to remove excess insulating film deposited for interlayer insulation, as well as for planarizing insulating films used for shallow trench isolation (STI) that insulates between the interlayer insulating film (ID) and the chip, and as a process for forming metallic conductive films such as wiring, contact plugs, and via contacts.

[0003] In the CMP (Chemical Polishing) process, the polishing speed, the degree of flattening of the polished surface, and the extent of scratch generation are important and are determined by the conditions of the CMP process, the type of slurry, the type of polishing pad, etc. High-purity cerium oxide particles are used in the cerium oxide slurry. In recent years, the manufacturing process of semiconductor devices has required achieving even greater miniaturization of wiring, and polishing scratches generated during polishing have become a problem.

[0004] Conventional cerium oxide slurries use particles ranging in size from 30 nm to 200 nm. While fine polishing scratches that occurred during polishing were not a problem as long as they were smaller than the conventional wiring width, this is now a problem in achieving sustained high levels of wiring miniaturization. Attempts have been made to reduce the average particle size of cerium oxide particles to address this problem. However, with existing particles, reducing the average particle size reduces the mechanical effect, leading to a decrease in polishing speed.

[0005] Thus, even when attempting to control the polishing speed and polishing scratches by controlling the average particle size of cerium oxide particles, it is extremely difficult to maintain the polishing speed while achieving the target level of polishing scratches.

[0006] Furthermore, conventional chemical mechanical polishing slurry compositions contain cerium oxide particles, Ce 3+ vs Ce 4+ While optimizing the ratio, we have been unable to present an optimized level of average particle size, and therefore, Ce on the cerium oxide surface 3+ In reality, research is needed on polishing slurries containing cerium oxide particles that exhibit a high oxide film removal rate despite their small particle size, by increasing the proportion of these particles. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention was devised to solve the above problems, and one embodiment of the present invention provides cerium oxide particles for chemical and mechanical polishing.

[0008] Another embodiment of the present invention provides a slurry composition for chemical and mechanical polishing.

[0009] Furthermore, another embodiment of the present invention provides a method for manufacturing a semiconductor device, which includes the step of polishing using the chemical mechanical polishing slurry composition.

[0010] Furthermore, another embodiment of the present invention provides a semiconductor device.

[0011] Furthermore, another embodiment of the present invention provides a method for producing cerium oxide particles for chemical and mechanical polishing.

[0012] However, the technical problems that this invention aims to solve are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by a person with ordinary skill in the art to which this invention belongs from the following description. [Means for solving the problem]

[0013] As a technical means to achieve the aforementioned technical challenges, one aspect of the present invention provides cerium oxide particles for chemical mechanical polishing, characterized in that, in an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight, the light transmittance for light with a wavelength of 500 nm is 50% or more.

[0014] The aqueous dispersion in which the cerium oxide particles are adjusted to 1.0% by weight may be characterized by having an average light transmittance of 50% or more for light with a wavelength of 450 to 800 nm.

[0015] When the cerium oxide particles are included in the chemical mechanical polishing slurry, the chemical mechanical polishing slurry may be characterized by being transparent.

[0016] The cerium oxide particles may be characterized by being monodispersible when contained in a chemical mechanical polishing slurry.

[0017] The particle size of the secondary particles of the cerium oxide particles, as measured by a dynamic light scattering (DLS) particle size analyzer, may be characterized by being between 1 and 30 nm.

[0018] The particle size of the secondary particles of the cerium oxide particles measured by a dynamic light scattering (DLS) particle size analyzer may be characterized in that it is 1 to 20 nm.

[0019] During X-ray diffraction (XRD) analysis, the particle size of the primary particles of the cerium oxide particles may be characterized in that it is 0.5 to 15 nm.

[0020] During transmission electron microscope (TEM) analysis, the particle size of the cerium oxide particles may be characterized in that it is 10 nm or less.

[0021] During small-angle X-ray scattering (SAXS) analysis, the particle size of the cerium oxide particles may be characterized in that it is 0.5 to 15 nm.

[0022] In the spectrum measured by Fourier transform infrared (FT-IR) spectroscopy, the infrared transmittance is 90% or more in the range of 3000 cm -1 ~3600 cm -1 and the infrared transmittance is 96% or less in the range of 720 cm -1 ~770 cm -1 This may be characterized.

[0023] On the surface of the cerium oxide particles, during X-ray photoelectron spectroscopy (XPS) analysis, the XPS peak showing the Ce-O bond energy showing Ce 3+ may appear at the first peak of 900.2 to 902. eV, the second peak of 896.4 to 898.4 eV, the third peak of 885.3 to 887.3 eV, and the fourth peak of 880.1 to 882.1 eV.

[0024] During X-ray photoelectron spectroscopy (XPS) analysis, the ratio of the sum of the XPS peak areas showing the Ce-O bond energy showing Ce 3+ to the total sum of the XPS peak areas showing the Ce-O bond energy showing Ce may be characterized in that it is 0.29 to 0.70.

[0025] 455 cm -1~460cm -1 It may be characterized by having a first Raman peak within the band range.

[0026] 586cm -1 ~627cm -1 It may be characterized by having a second Raman peak within the band range.

[0027] 712cm -1 ~772cm -1 It may be characterized by having a third Raman peak within the band range.

[0028] The ratio (A / B) of the first Raman peak intensity (A) to the second Raman peak intensity (B) may be 25 or less.

[0029] The ratio of the first Raman peak intensity (A) to the third Raman peak intensity (C) (A / C) may be 50 or less.

[0030] The electron energy loss (EELS) spectrum may be characterized by including a first peak in the range of 876.5–886.5 eV and a second peak in the range of 894.5–904.5 eV, wherein the maximum intensity of the first peak is greater than the maximum intensity of the second peak.

[0031] It further includes a third peak at 886.5–889.5 eV and a fourth peak at 904.5–908.5 eV, and the sum of the total areas of the peaks in the spectrum (P t The ratio of the sum of the areas of the third peak section (P1) and the sum of the areas of the fourth peak section (P2) to ((P1+P2) / P t It may be characterized by the fact that ) is 0.1 or less.

[0032] Ce by X-ray absorption fine structure (XAFS) spectroscopy 3+ The peak areas A3 and Ce show 4+For the sum of the peak areas A4 that show, Ce 3+ It is possible that the ratio of the peak areas A3 (A3 / (A3+A4)) to the peak area A3 is 0.03 or greater.

[0033] Ce by XAFS (X-ray absorption fine structure) spectroscopy 3+ The peak areas A3 and Ce show 4+ For the sum of the peak areas A4 that show, Ce 3+ It is possible that the ratio of the peak areas A3 to A4, A3 / (A3+A4), is 0.1 or greater.

[0034] When measuring the XAFS spectrum, the maximum light absorption coefficient of the first peak may be in the range of 5730 eV to less than 5740 eV, and the maximum light absorption coefficient of the first peak may be 0.1 to 0.4.

[0035] When measuring the XAFS spectrum, the maximum light absorption coefficient of the second peak may be in the range of 5740 eV to less than 5760 eV, and the maximum light absorption coefficient of the second peak may be less than 0.6.

[0036] The cerium oxide particles are characterized in that, during ultraviolet photoelectron spectroscopy (UPS) analysis, the maximum number of photoelectrons emitted per second (Counts) is within a range of kinetic energy of 10 eV or less.

[0037] The cerium oxide particles may be characterized in that, during UPS analysis, the maximum number of photoelectrons (Counts) emitted per second is in the kinetic energy range of 3 to 10 eV.

[0038] The cerium oxide particles may be characterized by exhibiting a work function value of 3.0 eV to 10.0 eV during UPS analysis.

[0039] The cerium oxide particles have a BET surface area value of 50 m². 2 It may be characterized by being less than or equal to / g.

[0040] The cerium oxide particles may be characterized by having an apparent density of 2.00 to 5.00 g / ml, as measured by the static method.

[0041] The cerium oxide particles may be characterized by having an apparent density of 2.90 to 5.00 g / ml as measured by the tap method.

[0042] When the photoluminescence (PL) of an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is measured at a wavelength of 325 nm, the maximum intensity of the first peak (λ1) at wavelengths of 435-465 nm may appear in the range of 0.1-30.

[0043] It may be characterized by the maximum intensity of the second peak (λ2) at wavelengths of 510-540 nm appearing in the range of 0.1-10.

[0044] The characteristic feature is that the intensity ratio (λ1 / λ2) of the first peak (λ1) to the second peak (λ2) at a wavelength of 510-540 nm is 5-15.

[0045] The aqueous dispersion in which the cerium oxide particles are adjusted to a content of 1.0% by weight is characterized in that, when expressed in the L*a*b* color system, the L* value is 95 or greater and the b* value is between 10 and 25.

[0046] (L* indicates brightness, a* indicates redness, and b* indicates yellowness.)

[0047] The aforementioned a* may be characterized by being between -12 and -3.

[0048] The present invention may be characterized in that when an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is centrifuged at a centrifugal force of 4250G for 30 minutes, the settling rate of the cerium oxide particles is 25% by weight or less.

[0049] Another aspect of the present invention provides a chemical mechanical polishing slurry composition comprising cerium oxide particles and a solvent, characterized in that an aqueous dispersion in which the content of the cerium oxide particles is adjusted to 1.0% by weight has a light transmittance of 50% or more for light with a wavelength of 500 nm.

[0050] The cerium oxide particles may be present in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the total slurry composition.

[0051] The aforementioned composition may be characterized by having a pH of 2 to 10.

[0052] The chemical mechanical polishing slurry composition may be characterized by comprising: 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; imidazoles; alkylamines; alcoholamines; quaternary amine hydroxides; ammonia; or a combination thereof.

[0053] The solvent may be characterized by being deionized water.

[0054] The chemical mechanical polishing slurry composition may be characterized by having a silicon oxide film polishing rate of 1,000 to 5,000 Å / min.

[0055] Another aspect of the present invention provides a chemical mechanical polishing slurry composition comprising cerium oxide particles and a solvent, wherein the cerium oxide particles are produced by a wet process, and the content of precursor substances in the slurry composition is 300 ppm or less by weight.

[0056] The chemical mechanical polishing slurry composition is characterized by containing cerium oxide particles in an amount of 0.001 to 5% or less based on the total weight.

[0057] Another aspect of the present invention provides a chemical mechanical polishing slurry composition characterized by comprising cerium oxide particles; a solvent; and a cationic polymer.

[0058] The present invention may be characterized by an increase in the oxide film polishing rate depending on the content of the aforementioned cationic polymer.

[0059] The cationic polymer may be characterized by increasing the polishing selectivity ratio of the oxide film / polysilicon film.

[0060] The content of the cationic polymer may be 0.001 to 1% by weight relative to the total weight of the chemical mechanical polishing slurry composition.

[0061] The cationic polymer may be characterized by being a polymer or copolymer containing an amine group or an ammonium group.

[0062] The cationic polymer may be characterized by being polydiallyldimethylammonium chloride, polyallylamine, polyethyleneimine, polydiallylamine, polypropyleneimine, polyacrylamide-co-diallydimethylammonium chloride, polyacrylamide, poly(trimethylammonioethyl methacrylate), dicyandiamide-diethylenetriamine copolymer, diallyldimethylamine / hydrochloride-acrylamide copolymer, dicyandiamide-formaldehyde copolymer, or a combination thereof.

[0063] The chemical mechanical polishing slurry composition may be characterized by having an oxide film / polysilicon film polishing selectivity ratio of 200 to 2,000.

[0064] Another aspect of the present invention provides a method for manufacturing a semiconductor device, which includes a step of polishing using the chemical mechanical polishing slurry composition.

[0065] Another aspect of the present invention provides a semiconductor device comprising a substrate and a trench filled with an insulating material on the substrate, wherein the trench is produced 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 and a solvent, and the light transmittance for light with a wavelength of 500 nm in an aqueous dispersion in which the content of the cerium oxide particles is adjusted to 1.0% by weight is 50% or more.

[0066] Another aspect of the present invention is the step of preparing raw material precursors; and The steps include: grinding or precipitating cerium oxide particles in a solution containing the raw material precursor to obtain a dispersion of cerium oxide particles for chemical and mechanical polishing;

[0067] The present invention provides a method for producing cerium oxide particles for chemical and mechanical polishing, characterized in that an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight has a light transmittance of 50% or more for light with a wavelength of 500 nm. [Effects of the Invention]

[0068] In the case of cerium oxide particles according to one embodiment of the present invention, the Ce on the surface of the cerium oxide 3+ By increasing the ratio of this compound, even with small particle size, it can maintain a high oxide film removal rate even at low concentrations when included in a chemical mechanical polishing slurry.

[0069] Furthermore, according to one embodiment of the present invention, it is possible to minimize surface defects on a wafer and, unlike the conventional trade-off relationship between surface defects and oxide film removal rate, it is possible to maximize the oxide film removal rate while minimizing surface defects, thereby providing cerium oxide particles and a slurry composition for chemical mechanical polishing.

[0070] Furthermore, according to one embodiment of the present invention, it can be confirmed that the addition of a cationic polymer further increases the oxide film polishing rate and simultaneously increases the selectivity ratio of the oxide film to the polysilicon film. Considering the conventional technical common sense that the addition of a cationic polymer usually sacrifices polishing speed to secure other properties, this can be said to be a unique effect of the present invention.

[0071] The effects of the present invention are not limited to those described above, but should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention as described in the claims. [Brief explanation of the drawing]

[0072] [Figure 1] This illustrates an oxide film removal mechanism according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view (1) showing a method for manufacturing a semiconductor device according to one embodiment of the present invention. [Figure 3] This is a cross-sectional view (2) showing a method for manufacturing a semiconductor device according to one embodiment of the present invention. [Figure 4] This is a cross-sectional view (3) showing a method for manufacturing a semiconductor device according to one embodiment of the present invention. [Figure 5] This is a cross-sectional view (4) showing a method for manufacturing a semiconductor device according to one embodiment of the present invention. [Figure 6] This is a cross-sectional view showing a method for manufacturing a semiconductor device according to one embodiment of the present invention. [Figure 7] This shows the stepwise process of chemical mechanical polishing and the structure of the chemical mechanical polishing (CMP) equipment relating to another embodiment of the present application (1). [Figure 8] This shows (2) the stepwise process of chemical mechanical polishing and the structure of chemical mechanical polishing (CMP) equipment related to another embodiment of the present application. [Figure 9] This is an image of a conventional dispersion of cerium oxide particles observed visually. [Figure 10] This is an image of a dispersion containing cerium oxide particles according to one embodiment of the present invention, observed visually. [Figure 11] This is a TEM image (1) of cerium oxide particles according to one embodiment of the present invention. [Figure 12] This is a TEM image (2) of cerium oxide particles according to one embodiment of the present invention. [Figure 13] This is a TEM image (3) of cerium oxide particles according to one embodiment of the present invention. [Figure 14] This is an SEM image of cerium oxide particles related to Comparative Example 1. [Figure 15] This is an SEM image of cerium oxide particles related to Comparative Example 2. [Figure 16] These are SEM and TEM images of cerium oxide particles related to Comparative Example 3. [Figure 17] This is an SEM image of cerium oxide particles related to Comparative Example 4. [Figure 18] These are TEM images of Comparative Examples 1-3. [Figure 19] This shows the results of particle size analysis by X-ray diffraction (XRD) of cerium oxide particles according to one embodiment of the present invention. [Figure 20] This is the result of small-angle X-ray scattering (SAXS) analysis of cerium oxide particles according to one embodiment of the present invention. [Figure 21] This is the result of dynamic light scattering (DLS) particle size analysis of cerium oxide particles according to one embodiment of the present invention. [Figure 22] This shows the spectral analysis results of cerium oxide particles and cerium hydroxide particles according to one embodiment of the present invention, obtained by Fourier transform infrared (FT-IR) spectroscopy. [Figure 23] The light transmittance of slurries containing cerium oxide particles according to one embodiment of the present invention and conventional cerium oxide particles from Comparative Examples 1 to 4 was measured using ultraviolet-visible (UV-vis) spectroscopy. [Figure 24] These are the intensity ratio and peak area results obtained by XRD (X-ray Diffraction) analysis of cerium oxide particles according to one embodiment of the present invention. [Figure 25]This is the result of X-ray photoelectron spectroscopy (XPS) analysis of cerium oxide particles according to one embodiment of the present invention. [Figure 26] This shows the results of X-ray photoelectron spectroscopy (XPS) analysis of cerium oxide particles related to Comparative Example 3. [Figure 27] This is the result of Raman peak analysis of cerium oxide particles according to one embodiment of the present invention. [Figure 28] This is the Raman peak analysis result of cerium oxide particles related to Comparative Example 1. [Figure 29] This is the Raman peak analysis result of cerium oxide particles related to Comparative Example 3. [Figure 30] This is the result of electron energy loss spectroscopy (EELS) analysis of cerium oxide particles according to one embodiment of the present invention. [Figure 31] This shows the results of electron energy loss spectroscopy (EELS) analysis of cerium oxide particles related to Comparative Example 3. [Figure 32] This shows the results of electron energy loss spectroscopy (EELS) analysis of cerium oxide particles related to Comparative Example 4. [Figure 33] This is the result of X-ray absorption fine structure (XAFS) spectral analysis of cerium oxide particles according to one embodiment of the present invention. [Figure 34] This shows the results of the X-ray absorption fine structure (XAFS) spectral analysis of cerium oxide particles related to Comparative Example 3. [Figure 35] This shows the results of ultraviolet photoelectron spectroscopy (UPS) analysis of an aqueous dispersion containing 1% by mass of cerium oxide particles according to one embodiment of the present invention. [Figure 36] This shows the results of ultraviolet photoelectron spectroscopy (UPS) analysis of an aqueous dispersion containing 1% by mass of cerium oxide particles according to Comparative Example 3. [Figure 37] This shows the results of ultraviolet photoelectron spectroscopy (UPS) analysis of an aqueous dispersion containing 1% by mass of cerium oxide particles according to Comparative Example 4. [Figure 38] This is the result of BET surface area measurement of cerium oxide particles according to one embodiment of the present invention. [Figure 39] This shows the BET surface area measurement results for cerium oxide particles related to Comparative Example 1. [Figure 40] This shows the results of measuring the photoluminescence intensity (PL) of cerium oxide particles according to one embodiment of the present invention. [Figure 41] This shows the results of measuring the luminescence intensity (PL) of cerium oxide particles related to Comparative Example 3. [Figure 42] This shows the results of measuring the luminescence intensity (PL) of cerium oxide particles related to Comparative Example 4. [Figure 43] This is a dispersion containing 1% by mass of cerium oxide particles according to one embodiment of the present invention, prepared for measuring a color system. [Figure 44] This is a dispersion containing 1% by mass of cerium oxide particles, as prepared for Comparative Example 3 to measure the color system. [Figure 45] This is an image (1) of an oxide wafer scanned 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 60 nm class cerium oxide particles. [Figure 46] This is an image (2) of an oxide wafer scanned 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 60 nm class cerium oxide particles. [Figure 47] This shows the measurement of the oxide film polishing rate behavior of a CMP slurry composition containing cerium oxide particles according to one embodiment of the present invention upon addition of a cationic polymer. [Modes for carrying out the invention]

[0073] The following describes in detail embodiments of the present invention so that those with ordinary skill in the art to which the present invention pertains can easily implement it. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein.

[0074] Manufacturing Example 1. Production of Cerium Oxide Particles The cerium oxide particles according to one embodiment of the present invention can be synthesized through chemical synthesis using a bottom-up approach. In the embodiment of the present invention, cerium oxide particles were produced by one of the cerium oxide particle production methods selected from those presented below.

[0075] According to one embodiment of the present invention, first, approximately 2-4 kg of cerium nitrate was 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 prepared 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 precipitated quickly when left to stand after stirring was complete. After removing the supernatant (supernatant) from which the precipitate had been removed, a certain amount of deionized water was added to produce a pale yellow cerium oxide particle dispersion. The prepared dispersion was filtered through a membrane filter to obtain a clear yellow cerium oxide dispersion.

[0076] In a manufacturing method according to another embodiment of the present invention, first, 150 g of cerium oxide or cerium hydroxide was dispersed in 3 kg of deionized water and stirred until the particles did not settle. Nitric acid was added to the mixture until the pH was 1.0 or lower. The mixture was added to a milling machine packed with 0.05 mm zirconia beads and ground while circulating at 4,000 rpm. As milling progressed, it was observed that the white, opaque cerium oxide dispersion gradually changed into a yellow, transparent cerium oxide dispersion. After milling was completed, the yellow, transparent cerium oxide dispersion produced was filtered through a membrane filter to obtain a pure yellow, transparent cerium oxide dispersion.

[0077] In another embodiment of the present invention, approximately 2-4 kg of ceric ammonium nitrate was first added to a sufficient amount of ethanol and stirred. 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 precipitated rapidly when left to stand after stirring was complete. After removing the supernatant liquid from which the precipitate had been removed, a certain amount of deionized water was added to produce a cerium oxide particle dispersion. The prepared dispersion was circulated and filtered through a membrane filter to obtain a clear cerium oxide dispersion.

[0078] In another embodiment of the present invention, 1.1 kg of cerium nitrate and 10 kg of deionized water were first mixed in a reaction vessel. The stirring speed of the reaction vessel was maintained at 200 rpm, and the temperature was kept at room temperature. A 1:1 mixture of 25% aqueous 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 reactor temperature was raised to 100°C, and the reaction was carried out for 4 hours. During the reaction, large pale purple particles dissociated, and yellow transparent cerium oxide nanoparticles were produced. The obtained particles were circulated through a membrane filter to remove purified water and obtain a pure cerium oxide nanoparticle dispersion.

[0079] Manufacturing Example 2. Preparation of CMP Slurry Containing Cerium Oxide Particles The cerium oxide particles produced in Production Example 1 were added to deionized water to adjust the abrasive concentration to 0.05% by weight, and triethanolamine was added to adjust the pH to 5.5 to produce a CMP slurry.

[0080] As shown in Figures 9 and 10, in the case of a conventional slurry containing ceria particles, high turbidity can be observed even with the naked eye, whereas in the case of a slurry containing cerium oxide particles of the present invention, transparency can be observed, and it can be inferred that it has monodisperse properties.

[0081] Comparative Examples 1-4. Production of conventional slurry compositions containing ceria particles Commercially available wet-process cerium oxide particles with average particle sizes of 10, 30, and 60 nm, respectively, and cerium oxide particles of the 10-20 nm class produced separately by calcination were obtained. These were added to deionized water to adjust the abrasive concentration to 0.05% by weight, and ammonia was added as a pH adjuster to achieve a final pH of 5.5, thereby producing a CMP slurry.

[0082] Experimental Example 1. SEM and TEM analysis of cerium oxide particles A dispersion of Production Example 1 according to one embodiment of the present invention was dried at approximately 80-90°C to prepare cerium oxide particles (primary particles) in powder form (Sample A). On the other hand, cerium oxide particles used in the production of the dispersions of Comparative Examples 1-4 were prepared respectively (Samples B1, B2, B3, and B4). Images were taken of each of the prepared samples using a TEM measuring instrument.

[0083] Figures 11 to 13 are TEM images of cerium oxide particles according to one embodiment of the present invention.

[0084] Referring to Figures 11 to 13, it was confirmed that the average particle size of cerium oxide particles produced by one embodiment of the present invention, as measured by TEM, was approximately 4 nm or less (3.9 nm, 3.4 nm, and 2.9 nm, respectively, in repeated measurements). It was confirmed that the average primary particle size of the cerium oxide particles according to one embodiment of the present invention was 4 nm or less. Furthermore, it was confirmed that the cerium oxide particles had a spherical shape on average. Spherical cerium oxide particles with small particle size and a relatively uniform particle size distribution can have a large specific surface area and are characterized by excellent dispersion stability and storage stability.

[0085] Figures 14 to 17 show SEM images of conventional cerium oxide particles related to the comparative example.

[0086] Referring to Figures 14 to 17, it can be seen that conventionally available cerium oxide particles exhibit particle sizes appropriate to their respective size grades, and even in the case of particles separately manufactured by calcination, all exhibit primary particle sizes with an average particle size of over 10 nm. Comparing this with the average particle size of cerium oxide particles according to one embodiment of the present invention shown in Figures 11 to 13, which was measured by TEM and was 4 nm or less, it can be confirmed that conventional cerium oxide particles and general cerium oxide particles manufactured by calcination have remarkably coarse particle sizes. In contrast, it has been confirmed that the cerium oxide particles of the present invention are formed with small particle sizes (primary particles), and it can be predicted that the smaller the cerium oxide particle size, the more defects such as scratches that occur on the surface of the film to be polished can be reduced.

[0087] Figure 18 shows a TEM image of conventional cerium oxide particles, which are a comparative example. Referring to Figure 18, it can be seen that conventional cerium oxide particles with a particle size of 10 nm include particles with edges 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 explained above, the cerium oxide particles according to the embodiment of the present invention generally have a spherical shape. Thus, the cerium oxide particles of the present invention have a spherical particle shape and a fine particle size, so they can contain a large number of particles. Therefore, when polishing a silicon oxide film, the probability of surface defects is reduced and the flatness over a wide area can be increased.

[0088] Experimental Example 2. X-ray Diffraction (XRD) Analysis of Cerium Oxide Particles A dispersion of Production Example 1 according to one embodiment of the present invention was dried at approximately 80-90°C to prepare cerium oxide particles (primary particles) in powder form (Sample A). The prepared Sample A was analyzed using an XRD instrument (Rigaku, Ultima IV). The XRD was set to Cu Kα (λ=1.5418Å), 40kV, and 40mA.

[0089] Figure 19 shows the XRD (X-ray Diffraction) pattern of cerium oxide particles according to one embodiment of the present invention. The particle size of the cerium oxide particles, derived from the analysis of the XRD pattern, is shown in Table 1 below.

[0090] [Table 1]

[0091] Referring to Figure 19 and Table 1, the XRD analysis results for sample A show an XRD spectrum in the form shown in Figure 19 (X-axis: 2-theta (degree scattering angle), Y-axis: intensity signal strength). ) was derived. The grain size of the crystal grains calculated from the above spectrum was 3.25 nm. This is at a similar level to the TEM analysis results of Experimental Example 1, and through this, the present invention We were able to confirm that the particles were single crystals.

[0092] Experimental Example 3. Small-Angle X-ray Scattering (SAXS) Analysis of Cerium Oxide Particles The particle size of cerium oxide particles according to one embodiment of the present invention was analyzed using small-angle X-ray scattering (SAXS), and the results are shown in Figure 20.

[0093] Referring to Figure 20, it can be seen that the particle size of the cerium oxide particles according to the embodiment of the present invention has an average particle radius of 2.41 nm and is in the range of 10 nm or less. This confirms that the particle size of the cerium oxide particles according to the embodiment of the present invention is far finer than that of conventional cerium oxide particles, and therefore, when polishing a silicon oxide film using the cerium oxide particles according to the embodiment of the present invention, the rate of surface defect occurrence can be further suppressed.

[0094] Experimental Example 4. Dynamic Light Scattering (DLS) Particle Size Analysis of Cerium Oxide Particles using a Particle Size Analyzer The slurry composition of Production Example 2, and the slurry compositions of Comparative Examples 1, 2, 3, and 4 according to one embodiment of the present invention were prepared as samples. Each of the prepared samples was analyzed using a DLS instrument.

[0095] Figure 21 shows the results of dynamic light scattering (DLS) analysis (Malvern Zetasizer Ultra) of cerium oxide particles according to one embodiment of the present invention. Table 2 below shows the D50 values ​​obtained by dynamic light scattering (DLS) analysis for cerium oxide particles according to one embodiment of the present invention and cerium oxide particles of a comparative example.

[0096] [Table 2]

[0097] Referring to Figure 21 and Table 2, the cerium oxide particles according to the embodiment of the present invention have a secondary particle size D50 value of approximately 5.78 nm, which was measured to be 10 nm or less. Compared to the primary particle size measured by TEM in Experimental Example 1 (see Figures 11 to 13), this is at a level of approximately 148 to 199%, and it was confirmed that the particles hardly aggregated in the slurry, were monodisperse, and showed almost no change in particle size.

[0098] In contrast, dynamic light scattering (DLS) measurements of conventional cerium oxide particles confirmed that the D50 particle size exceeds 30 nm. Even in the case of 10 nm class cerium oxide particles, the D50 value of the secondary particle size measured by dynamic light scattering (DLS) is approximately 336% of the primary particle size measured by TEM. This indicates that conventional cerium oxide particles have much larger secondary particle sizes, leading to significant aggregation.

[0099] Therefore, it can be seen that the cerium oxide particles according to one embodiment of the present invention exhibit lower aggregation in the slurry and can be dispersed in the slurry in a more monodisperse form than the cerium oxide particles of the prior art according to one comparative example.

[0100] Experimental Example 5. Confirmation of cerium oxide particle formation by Fourier transform infrared (FT-IR) spectroscopy. Figure 22 shows the FT-IR spectroscopic analysis results of a powder consisting of cerium oxide particles manufactured according to one embodiment of the present invention, and a powder consisting of ordinary cerium hydroxide particles.

[0101] Analysis of the FT-IR spectral spectrum in Figure 22 revealed that the powder consisting of cerium oxide particles according to one embodiment of the present invention exhibits a 3000 cm⁻¹ spectrum. -1 ~3600cm -1 The infrared transmittance in the range is approximately 92-93%, and at 720cm -1 ~770cm -1 The infrared transmittance in this range can be confirmed to be approximately 93-95%. Regarding this, the FT-IR spectrum of a powder consisting of ordinary cerium hydroxide particles at 3000 cm² was observed. -1 ~3600cm -1 The infrared transmittance in the range is 75-90%, and at 720cm -1 ~770cm -1 Compared to the infrared transmittance of 97-99% in the range of 3000 cm², the cerium oxide particles produced according to one embodiment of the present invention have an infrared transmittance of 97-99%. -1 ~3600cm -1 The band formed by the OH group of cerium hydroxide particles within the range is the same as that of normal cerium hydroxide It appears weaker than that of mu particles, and at 720 cm -1 From 770cm -1 It can be confirmed that a peak due to Ce-O stretching is formed within this range.

[0102] Experimental Example 6. Measurement of light transmittance of a slurry containing cerium oxide particles. A slurry composition (Sample A) was prepared in the same manner as in Production Example 2, except that the weight ratio of cerium oxide particles in the CMP slurry was set to 1% by weight. On the other hand, slurry compositions were prepared in the same manner as in Comparative Examples 1, 2, 3, and 4 (Samples B1, B2, B3, and B4, respectively), except that the weight ratio of cerium oxide particles in the CMP slurry was set to 1% by weight. The transmittance for light in the range of 200 to 1100 nm was measured for each sample using a UV-Vis spectrometer (JASCO).

[0103] Figure 23 shows the results of measuring the light transmittance of slurries containing cerium oxide particles according to one embodiment of the present invention and conventional cerium oxide particles from Comparative Examples 1 to 4 using ultraviolet-visible (UV-vis) spectroscopy.

[0104] Cerium oxide particles according to one embodiment and a comparative example of the present invention were added to deionized water to an abrasive concentration of 1.0 wt%, and a CMP slurry was prepared, from which the light transmittance was analyzed. The optical spectrum was measured in the range of 200 to 1,100 nm using a UV-vis spectrophotometer (Jasco UV-vis spectrophotometer).

[0105] Table 3 below summarizes the transmittance (%) of Sample A and Samples B1-B4 at wavelengths of 500nm, 600nm, and 700nm, respectively, as shown in the UV-Vis analysis graph.

[0106] [Table 3]

[0107] According to Figure 23 and Table 3, it can be confirmed that in the case of the slurry containing cerium oxide particles of the present invention, 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.

[0108] In contrast, the light transmittance of slurries containing conventional cerium oxide particles using Comparative Examples 1-4 (conventional cerium oxide particles of 10nm, 30nm, and 60nm class, and ceria particles produced by calcination) was measured. Comparative Example 4 (calcined ceria particles) had a light transmittance of almost 0%, indicating that the light transmittance of the slurry of Comparative Example 1, which contains commercially available conventional cerium oxide particles of 10nm class, was less than 80% on average, and the light transmittance at a wavelength of 500nm was less than 50%. In the case of Comparative Examples 2 and 3, the particle size of the primary particles was also coarse at 30nm and 60nm, respectively, and the particle size of the secondary particles was also coarse compared to the examples of the present invention (i.e., the aggregation in the slurry was greater), so it can be seen that they showed a transmittance of less than 20% in the visible light region.

[0109] In contrast, cerium oxide particles according to one embodiment of the present invention can be confirmed to exhibit a light transmittance of 90% or more in the visible light region. This means that, in the case of cerium oxide particles of the present invention, the particle size of the primary particles themselves is fine, and aggregation into secondary particles is less than that of conventional cerium oxide particles. It is generally known that when secondary particles exceed 20 nm, the opacity of the slurry composition can be observed even with the naked eye, and the light transmittance in the visible light region is less than 80%.

[0110] According to the slurry composition of the present invention, if the particle size of the primary cerium oxide particles is small and the aggregation of secondary particles is small, the light transmittance is high, the dispersion stability is high and the particles can be uniformly distributed, and it can be easily predicted that the probability of defects such as scratches occurring on the surface will be reduced when polishing a film to be polished using the slurry composition containing the particles.

[0111] Experimental Example 7. Peak Area Ratio of Cerium Oxide Particles by XRD Analysis Figure 24 shows the intensity ratio and peak area results obtained by XRD (X-ray Diffraction) analysis of cerium oxide particles according to one embodiment of the invention.

[0112] The XRD analysis results in Figure 24 show that the peak area of ​​the (111) plane of the cerium oxide particles according to one embodiment of the present invention is approximately 496.9, and the peak area of ​​the (200) plane is approximately 150.1. Here, the ratio of the peak area of ​​the (111) plane to the peak area of ​​the (200) plane is approximately 3.3. When the main peaks were examined using a library, it was confirmed that the particles produced by the embodiment of the present invention were cerium oxide particles.

[0113] Experimental Example 8. XPS Analysis of Cerium Oxide Particles Figures 25 and 26 show the XPS analysis results of cerium oxide particles according to one embodiment of the present invention and conventional 60 nm class cerium oxide particles according to Comparative Example 3. XPS (X-ray photoelectron spectroscopy) is a method of analyzing cerium oxide when irradiated with soft X-rays. 3+ Peaks appearing at 900.2–902.2 eV, 896.4–898.4 eV, 885.3–887.3 eV, and 880.1–882.1 eV, which indicate Ce-O bond energies, were measured, and the atomic percentage was analyzed by XPS fitting to determine the Ce-O bond energy in cerium oxide particles. 3+ and Ce 4+ The content can be measured. Table 4 below shows the XPS results data of cerium oxide particles according to an example of the present invention.

[0114] [Table 4]

[0115] From the XPS analysis results, Ce was found to be derived from the chemical formula described above. 3+ The result of calculating the content was Ce 3+ It can be seen that the content is 30% or more. Ce in cerium oxide particles 3+ Since these are the reactive sites, it can be seen that this increases the amount of polishing. Using the method described above, comparative data with conventional cerium oxide particles is shown in Table 5 below.

[0116] [Table 5]

[0117] In the case of cerium oxide particles according to one embodiment of the present invention, as shown in Table 5 above, Ce 3+ The content is approximately 36.9 atomic%, and as shown in Table 5, this is compared to conventional 60nm class cerium oxide particles. 3+ The content is less than 14 atomic percent, and compared to the approximately 16.8% of cerium oxide particles produced by hydrothermal synthesis under supercritical or subcritical conditions of the 10 nm class, as known from conventional literature, the Ce content is high. 3+ It can be confirmed that it contains Ce. 3+ When the content is at a high level, as in the examples of the present invention, the polishing rate on silicon-containing substrates can be increased by the chemical polishing mechanism that forms Si-O-Ce between silica and cerium.

[0118] Experimental Example 9. Analysis of cerium oxide particles by Raman spectroscopy. Figures 27-29 show the results of Raman spectroscopy analysis of cerium oxide particles according to one embodiment of the present invention, conventional 10 nm class cerium oxide particles, and conventional 60 nm class cerium oxide particles, respectively. For each of the samples from the above embodiment, Comparative Example 1, and Comparative Example 3, the Raman spectra (X-axis: Raman shift (cm)) are shown in the form of Figures 27, 28, and 29, respectively. -1 The Y-axis (Counts) was derived. The analysis results for the derived Raman spectrum are shown in Table 6 below.

[0119] [Table 6]

[0120] Referring to Figures 27-29 and Table 6, the conventional cerium oxide particles in Comparative Examples 1 and 3 reached 462 cm³.-1 While the first Raman peak is present in the vicinity, the cerium oxide particles according to the embodiment of the present invention exhibit vibrations at 457 cm⁻¹. -1 A first Raman peak can be confirmed in the vicinity. In the case of cerium oxide particles according to the examples of the present invention, Ce 4+ Ce 3+ It is partially reduced, and defects are induced in the cubic fluorite lattice structure of the cerium oxide particles, resulting in oxygen vacancies. As vacancies increase, a shift in the first Raman peak is likely to occur. Furthermore, due to these differences in particle structure, it can be confirmed that the intensity of the second Raman peak in the example sample is higher than that of Comparative Examples 1 and 3.

[0121] Furthermore, in the cerium oxide particles according to the embodiment of the present invention, the values ​​were 457, 607, and 742 cm². -1 While the peaks shown were as follows, in the case of Comparative Example 1 and Comparative Example 3, the peak was approximately 607 cm². -1 The second peak was observed to be at a level that was barely detectable, or appeared with very weak intensity, at approximately 742 cm. -1 Unlike in the examples, the third peak was not detected.

[0122] On the other hand, the ratio of the first Raman peak intensity (A) to the second Raman peak intensity (B) (A / B) was confirmed to be 15.4, 46.0, and 66.4 for Example, Comparative Example 1, and Comparative Example 3, respectively. Thus, it can be confirmed that the A / B value for the sample in Example is much smaller than that of Comparative Examples 1 and 3. In this example, the ratio of the first Raman peak intensity (A) to the third Raman peak intensity (C) (A / C) is 50 or less, but in Comparative Examples 1 and 3, the third Raman peak was not detected, and therefore A / C could not be calculated. This is because Ce in cerium oxide particles 3+ This can be interpreted as a result of an increased proportion of defects (oxygen vacancies) due to the increased content.

[0123] From the above results, the cerium oxide particles according to one embodiment of the present invention have a higher Ce content compared to the conventional cerium oxide particles in the comparative example. 3+ It can be expected that it contains [something].

[0124] Experimental Example 10. Electron Energy Loss Spectroscopy (EELS) Spectral Analysis of Cerium Oxide Particles The slurry composition of Production Example 2, Comparative Example 3, and Comparative Example 4, all according to one embodiment of the present invention, were prepared as samples.

[0125] Each of the prepared samples was analyzed using an EELS measuring instrument. The EELS measurement was performed on the core-loss region, which is the energy loss interval of 50 eV or more. The ionization edge observed in the core-loss region can be used to distinguish peaks depending on the oxidation state of the sample being measured, thereby identifying the Ce of cerium oxide particles. 4+ The content was analyzed quantitatively.

[0126] Analysis of the samples using an EELS analyzer yielded EELS spectra for each of the samples from Example, Comparative Example 3, and Comparative Example 4, in the form shown in Figures 30 to 32, respectively (X-axis: binding energy (eV), Y-axis: intensity (au); signal intensity in arbitrary units).

[0127] Analysis revealed that the EELS spectrum of the example contained a first peak at approximately 876.5–886.5 eV and a second peak at 894.5–904.5 eV, characterized in that the maximum intensity of the first peak was greater than the maximum intensity of the second peak. 3+ It can be confirmed that it follows the EELS spectral trend. In contrast, the EELS spectra of Comparative Examples 3 and 4 show that the maximum peak intensity of the second peak is greater than the maximum peak intensity of the first peak, Ce 4+It can be confirmed that the EELS spectral trend follows that of the cerium oxide particles in the example. 3+ While the EELS spectrum of the cerium oxide particles of Comparative Examples 3 and 4 follows the trend of Ce 4+ This means that it follows the trend of the EELS spectrum.

[0128] On the other hand, the EELS spectrum of the cerium oxide particles may further include a third peak interval of 886.5–889.5 eV and a fourth peak interval of 904.5–908.5 eV, and the peak areas of the third and fourth peak intervals represent the Ce of the cerium oxide particles. 4+ This peak may indicate an oxidation state. Based on the EELS spectra in Figures 30 to 32, the peak area ratio for a specific binding energy range was derived and is shown in Tables 7 to 9 (results data for Example, Comparative Example 3, and Comparative Example 4, respectively). As a result of the EELS spectral analysis, in the cerium oxide particles according to one embodiment of the present invention, the sum of the total EELS peak areas (P t The ratio of the sum of the areas of the third peak interval (P1) to (P1 / P) t The percentages for Comparative Example 3 were calculated as 1%, 1%, 0%, and 0%, while those for Comparative Example 4 were calculated as 3%, 3%, 3%, and 4%.

[0129] Furthermore, in the case of cerium oxide particles according to one embodiment of the present invention, the sum of the total EELS peak areas (P t The area ratio of the area of ​​the third peak section (P1) and the area of ​​the fourth peak (P2) to ((P1+P2) / P t The average content of Ce is approximately 5.8% or less, while that of Comparative Example 3 is approximately 13% or more, and that of Comparative Example 4 is approximately 12% or more. From this, it can be seen that the cerium oxide particles according to one embodiment of the present invention have a lower Ce content compared to the cerium oxide particles of Comparative Examples 3 and 4. 4+ It can be confirmed that it possesses [this characteristic].

[0130] [Table 7]

[0131] [Table 8]

[0132] [Table 9]

[0133] Experimental Example 11. XAFS (X-ray absorption fine structure) spectral analysis of cerium oxide particles Samples of the slurry composition of Production Example 2 and the slurry composition of Comparative Example 3, both relating to one embodiment of the present invention, were prepared.

[0134] Each of the prepared samples was analyzed using an XAFS measuring instrument. XAFS is an analytical method that irradiates a sample with high-intensity X-rays and measures the intensity of the absorbed X-rays. Based on the X-ray absorption spectrum derived by measuring the optical absorption coefficient (xμ) due to the X-ray energy (eV), the Ce within the particle was analyzed. 3+ and Ce 4+ The weight ratio (wt%) of such components can be confirmed. In this case, the absorption spectrum was derived using the X-ray absorption near-edge structure (XANES) method, which analyzes the XAFS spectrum within 50 eV near the absorption edge where X-ray absorption increases sharply.

[0135] XAFS analysis results were obtained for each sample of Example and Comparative Example 3, and the XAFS spectra (X-axis: X-ray energy X (eV), Y-axis: X-ray light absorption coefficient xμ (E)) were derived as shown in Figures 33 and 34, respectively. As shown in Figures 33 and 34, absorption edges were formed in the range of approximately 5745 to 5755 eV for all samples of Example and Comparative Example 3. On the other hand, Ce 3+The peak (P1) where electron transitions strongly occur due to X-ray absorption by Ce was formed in the range of approximately 5735-5740 eV. 4+ We confirmed that a peak (P2) where strong electron transitions occur due to X-ray absorption is formed in the range of approximately 5745-5755 eV.

[0136] As a result of examining the light absorption coefficients for P1 and P2, it was found that in the example of the present invention, the levels were approximately 0.1 to 0.2 and 0.5 to 0.6, respectively, while in Comparative Example 3, the levels were less than 0.1 and greater than 0.6, respectively.

[0137] Based on the above analysis results, the respective Ce for the samples in Example and Comparative Example 3 3+ and Ce 4+ The peak area and area ratio can be confirmed to be as shown in Table 10 below.

[0138] [Table 10]

[0139] Referring to Table 10 above, Ce on the surface of cerium oxide particles according to one embodiment of the present invention 3+ The area ratio of Ce on the surface of cerium oxide particles in Comparative Example 3 3+ It can be confirmed that the area ratio is approximately four times higher than that of the conventional cerium oxide particles of the comparative example, and therefore it can be expected that the embodiment of the present invention will have a higher polishing rate than the conventional cerium oxide particles of the comparative example.

[0140] Experimental Example 12. UPS analysis of cerium oxide particles Cerium oxide particles according to one embodiment of the present invention, and samples of Comparative Examples 3 and 4 were prepared.

[0141] Figures 35 to 37 show the UPS analysis results for cerium oxide particles according to one embodiment of the present invention, conventional cerium oxide particles of the 60 nm class, and conventional cerium oxide particles manufactured by calcination.

[0142] Table 11 summarizes the work function values ​​based on the distinction between cerium oxide particles according to one embodiment of the present invention and the conventional cerium oxide particles.

[0143] In one embodiment, it was confirmed that the cerium oxide particles according to one embodiment of the present application had a maximum number of photoelectrons emitted per second (Counts, Y-axis) in the range of kinetic energy 8 to 10 eV, while in Comparative Examples 3 and 4, it was found that the maximum value of kinetic energy was in the range of 11 to 13 eV. From these results, it was possible to derive that the embodiment had a work function of 3.16 eV, while Comparative Examples 3 and 4 had work functions of 2.37 eV and 2.37 eV, respectively.

[0144] In one specific example, UPS analysis is performed on the measured kinetic energy (E kin ) Through the value of the binding energy (E b ) is derived, and from the derived binding energy graph, the Fermi level (E) of the sample is determined. F ) and vacuum level (E cutoff ) could be derived. Therefore, the Fermi level (E F ) and vacuum level (E cutoff The work function φ value was obtained by applying the value to Equation 1 below. In this case, hv is the source energy used when emitting ultraviolet light and represents the energy of the incident light, with helium (He) used as the source (He|UPS=21.22eV). The work function values ​​obtained from the analysis are shown in Table 11 below.

[0145] [Formula 1] φ = hv - |E f -E cutoff |

[0146] [Table 11]

[0147] Referring to Table 11, it was found that the work function value of the cerium oxide particles according to one embodiment of the present invention was the largest. As the particle size decreases, the difference in energy levels between sample orbitals gradually increases, resulting in a high energy band gap. From this, it could be predicted that the particle size of the cerium oxide particles according to one embodiment of the present invention is sufficiently smaller than that of conventional cerium oxide particles, resulting in a high energy band gap, which affects the Fermi level and vacuum level, causing a change in the energy value of the work function. Therefore, the work function value derived by UPS analysis indicates that the particle size of the cerium oxide particles according to one embodiment of the present invention is sufficiently smaller than that of conventional cerium oxide particles, and that the aggregation is very low. Because of this low aggregation and monodisperse characteristic, when the cerium oxide particles according to one embodiment of the present invention are used in a chemical mechanical polishing slurry, the number of particles in contact with the wafer can be maximized, the polishing speed of the oxide film can be increased, and the particle size itself is fine, minimizing defects on the wafer surface.

[0148] Experimental Example 13. BET surface area analysis of cerium oxide particles To measure the BET surface area, 1.0 g each of the cerium oxide particle powder according to the embodiment of the present invention and the cerium oxide particle powder according to Comparative Example 1 were pre-treated by degassing at 200°C for 1 hour each time until the residual pressure was below a predetermined value. Then, the amount of nitrogen gas adsorbed due to the increase in relative pressure was measured using a BET (Tristar II plus, Micrometrics) under 77K conditions, and the BET surface area values ​​calculated from the adsorption amount are shown in Figures 38 and 39 and Table 12 below.

[0149] [Table 12]

[0150] Referring to Table 12, when general pretreatment conditions (200°C, 1 hour) are applied, the cerium oxide particle powder according to the embodiment of the present invention has a BET surface area value of 50 m² when measured five times under the same conditions. 2 While the BET surface area value is less than / g, the cerium oxide particle powder of Comparative Example 1, when measured five times under the same conditions, had a BET surface area value of 80 m². 2 It can be confirmed that the value exceeds / g. The values ​​for such comparative examples are similar to the BET surface area values ​​of 10nm class cerium oxide particles known from standard literature.

[0151] From the results above, contrary to the general trend that the BET surface area value increases as the particle size decreases, it was confirmed that the cerium oxide particle powder according to the examples of the present invention has a smaller BET surface area value than the cerium oxide particle powder of Comparative Example 1, which has a coarser particle size. This means that the cerium oxide particles according to the examples of the present invention have a finer particle size than conventional cerium oxide particles, and therefore can be packed at a higher density when powdered. Furthermore, in the case of cerium oxide particles synthesized by self-assembly synthesis methods such as the sol-gel method and the bottom-up method, they have fewer -OH functional groups than cerium oxide particles synthesized by other synthesis methods, and therefore have smaller BET surface area and pore volume values. It can be captured.

[0152] Experimental Example 14. Analysis of the apparent density of cerium oxide particles A dispersion of Production Example 1 according to one embodiment of the present invention was dried at approximately 80-90°C to prepare cerium oxide particles in powder form (Sample A), and cerium oxide particles in powder form according to Comparative Examples 3 and 4, dried under the same conditions (Samples B and C, respectively). Tables 13 and 14 below show the apparent density and tap density measured for the prepared Sample A and Comparative Examples 3 and 4 according to one embodiment of the present invention.

[0153] [Table 13]

[0154] [Table 14]

[0155] Referring to Table 13, the apparent density of Sample A measured by the static method was 2.22 g / ml, while the apparent density of the 60 nm class cerium oxide particles of Comparative Example 3 was measured at 1.90 g / ml, and the apparent density of the calcined cerium oxide particles of Comparative Example 4 was measured at 1.30 g / ml. Furthermore, referring to Table 14, the apparent density of Sample A measured by the tap method was 2.94 g / ml, while the apparent density of the 60 nm class cerium oxide particles of Comparative Example 3 was 2.86 g / ml, and the apparent density of the calcined cerium oxide particles of Comparative Example 4 was 1.60 g / ml, confirming that they all have values ​​less than 2.90 g / ml. Thus, it can be confirmed that the cerium oxide particles according to one embodiment of the present application have a higher apparent density value than the cerium oxide particles of the comparative examples, which have coarser particle sizes, despite having finer primary particle sizes. Therefore, it can be confirmed that the cerium oxide particles according to the embodiment of the present invention have a particle size of 10 nm or less, which is finer than conventional cerium oxide particles, while having a relatively large apparent density.

[0156] Experimental Example 15. Measurement and Analysis of Photoluminescence (PL) of a Dispersion Containing Cerium Oxide Particles Figures 40 to 42 and Table 15 show the results of measuring the luminescence intensity of aqueous dispersions containing 1% by mass of cerium oxide particles according to one embodiment of the present invention, conventional 60 nm class cerium oxide particles, and 10 nm class cerium oxide particles produced by calcination. The luminescence intensity was measured under the following test conditions.

[0157] (1) Test equipment: Perkin Elmer LS-55 Fluorescence Spectrometer (2) Excitation wavelength: 325 nm (3) Emission filter: 350 nm (4) Excitation slit width: 10.0 nm (5) Emission slit width: 10.0 nm

[0158]

Table 15

[0159] Referring to FIGS. 40 to 42 and Table 15, when analyzing a fluorescence spectrometer (Fluorescence spectrometer) performed at an excitation wavelength (λ excitation ), it can be seen that in all three samples, an excitation peak (λ exc ) at a wavelength of about 325 nm, a first emission peak (λ ems1 ) at a wavelength of about 450 nm, and a second emission peak (λ ems2 ) at a wavelength of about 525 nm are shown.

[0160] In the case of the cerium oxide particles of the present invention, the ratio of the first emission peak to the second emission peak (λ ems1 / λ ems2 ) was found to be about 7.5, indicating a value of 5 or more. On the other hand, for conventional 10 nm - sized cerium oxide particles by the calcination method and commercially available 60 nm - sized cerium oxide particles, it was confirmed that the ratio of the first emission peak to the excitation peak (λ ems1 / λ exc ) all showed values exceeding 30, and it was confirmed that the ratio of the first emission peak to the second emission peak (λ ems1 / λ ems2 ) showed values less than 5.

[0161] In the case of the cerium oxide particles of the present invention, Ce 3+It can be seen that the intensity of the first emission peak, which shows the above, is smaller than that of conventional 10 nm class cerium oxide particles produced by calcination and commercially available 60 nm class cerium oxide particles. This is because, in the case of the cerium oxide particles of the present invention, aggregation from the dispersion to secondary particles is very small, resulting in good light transmission, and therefore the emission intensity is judged to be relatively weak. Furthermore, in the case of the cerium oxide particles of the present invention, unlike conventional 60 nm class particles or cerium oxide particles produced by calcination, the ratio of the first emission peak to the second emission peak (λ) ems1 / λ ems2 When the value of ) is 5 or higher, the cerium oxide particles of the present invention have a relatively high Ce on their surface. 3+ This can be interpreted as indicating that it contains Ce. Therefore, from this experimental example, in the case of cerium oxide particles of the present invention, when used in a slurry for chemical mechanical polishing, the Ce on the particle surface 3+ Despite its high content, the particles themselves are very fine and exhibit very little aggregation in the slurry. This results in a higher chemical polishing rate due to Si-O-Ce bonds between the cerium oxide particles and the oxide film substrate, thus improving the oxide film polishing rate.

[0162] Experimental Example 16. L*a*b* color system analysis of a dispersion containing cerium oxide particles. Figures 43 and 44 show an aqueous dispersion containing 1% by mass of cerium oxide particles according to one embodiment of the present invention, and a conventional aqueous dispersion containing 1% by mass of 60 nm class cerium oxide particles.

[0163] Tables 16 and 17 summarize the chromaticity values ​​in the L*a*b* color system for a dispersion containing 1% by mass of cerium oxide particles according to one embodiment of the present invention, and a conventional dispersion containing 1% by mass of 60 nm class cerium oxide particles.

[0164] In one embodiment, the analysis in the L*a*b* color space system was performed by ASTM E1164 (Standard practice for obtaining spectrometric data for object color evaluation) using CM-5 (KONICA MINOLTA, JAPAN). At this time, a Xenon lamp D65 was used as the light source, and the analysis was performed at a wavelength range of 360 to 740 nm with a wavelength interval of 10 nm. The analysis results are shown in Tables 16 and 17 below.

[0165] [Table 16]

[0166] [Table 17]

[0167] Referring to FIGS. 43 and 44, it can be visually observed that the aqueous dispersion containing cerium oxide particles of the present invention has a yellowish color. In the case of an aqueous dispersion containing conventional cerium oxide particles of about 60 nm, although it is opaque, it was found to be closer to white.

[0168] Furthermore, referring to Tables 16 and 17, it can be confirmed that in the case of a dispersion containing 1% by mass of cerium oxide particles according to one embodiment of the present invention, the average value of L* is approximately 99.7, the average value of a* is approximately -5.9, and the average value of b* is approximately 11.7. In contrast, in the case of a conventional dispersion containing 60nm class cerium oxide particles, it can be confirmed that the average value of L* is approximately 94.7, the average value of a* is approximately -2.2, and the average value of b* is approximately 0.1. Therefore, the cerium oxide particle dispersion according to the present invention satisfies the range of L* being 95 or higher and b* being 10 to 25. Compared to the conventional 60nm class cerium oxide particle dispersion, it has a larger L* value, indicating finer particle characteristics, and has a larger b* value, so it can be interpreted that the cerium oxide particle dispersion according to one embodiment of the present invention exhibits a higher yellow tint. When cerium oxide particles according to one embodiment of the present invention are shown in an aqueous dispersion containing them, their respective values ​​in the L*a*b* color system fall within the aforementioned range, and those showing particularly high yellowness indicate that the cerium oxide particles are very fine and exhibit monodisperse properties, as well as the Ce on the surface of the cerium oxide particles. 3+ This can be interpreted as meaning that the content is relatively very high.

[0169] Experimental Example 17. Settlement rate of cerium oxide particles during centrifugation. A slurry composition containing 1.0% by weight of cerium oxide particles according to one embodiment of the present application, and the slurry compositions containing 1.0% by weight of cerium oxide particles according to Comparative Examples 1 and 3 were each prepared as samples.

[0170] Using the aforementioned samples, centrifugation was performed using a high-speed centrifuge or ultra-high-speed centrifuge (Supra R22 (model name), manufactured by Hanil Science Industrial Co. Ltd., South Korea) under conditions starting from a slurry composition temperature of 25°C, while varying the centrifugal force to 2100G, 3300G, 4265G, 26188G, and 398282G. The settling rates of the cerium oxide particles during this process are shown in Table 18 below.

[0171] [Table 18]

[0172] Referring to Table 18 above, when a slurry composition containing 1.0% by weight of each cerium oxide particle is centrifuged, it can be confirmed that the settling rate of the cerium oxide particles according to one embodiment of the present invention is lower than that of the cerium oxide particles according to Comparative Examples 1 and 3 under the same conditions. For example, when centrifuged at a centrifugal force of 4,265 G for 30 minutes, the embodiment of the present invention shows a settling rate of 0% by weight, while Comparative Example 1 shows a settling rate of 27.14% by weight, and Comparative Example 3 shows a settling rate of 96.9% by weight when centrifuged at a smaller centrifugal force of 3,300 G for 10 minutes. Therefore, this may mean that the particle size of the primary and / or secondary particles of the cerium oxide particles in the embodiment of the present invention is finer than the particle size of the cerium oxide particles in Comparative Examples 1 and 3, and that they are monodisperse. Consequently, monodisperse particles come into contact with the wafer during the chemical mechanical polishing process, increasing the number of contacting particles and improving the oxide film polishing speed. Furthermore, it may mean that when polishing is performed using a slurry composition containing cerium oxide particles according to the embodiment of the present invention, the occurrence rate of polishing defects such as scratches on the wafer being polished can be reduced.

[0173] Experimental Example 18. Analysis of residual amount of cerium oxide precursor. An evaluation was conducted to measure the amount of precursor residue in the CMP slurry containing cerium oxide particles produced in Production Example 2. The slurry sample from Production Example 2 was produced in powder form through a process of drying at high temperature until powder was obtained, and then the residual powder was dissolved again in pure water. The precursor content in the solution dissolved in pure water was analyzed by ICP-MS, and the results, converted to a weight ratio of cerium oxide powder, showed that substances such as basic substances, solvents, and ammonia were hardly detected, and it was confirmed to be less than 300 ppm. "Hardly detected" means, more specifically, that the amount contained was significantly less than PPM or less, or that it was not contained at all. Therefore, it could be predicted that the cerium oxide particles in this embodiment of the present application, after being produced in the form of a dispersion by a wet process, do not require a separate separation or grinding process to redisperse them in the slurry solvent.

[0174] [Table 19]

[0175] Experimental Example 19. Comparison of the oxide film polishing rate of cerium oxide particles. The slurry composition of Production Example 2, Comparative Example 1, and Comparative Example 3, according to one embodiment of the present application, were each prepared as samples.

[0176] Polishing of the oxide film wafer using the aforementioned sample was performed using a polishing machine (Reflexion® LK CMP, Applied Materials). Specifically, a PE-TEOS silicon oxide film wafer (300 mm PE-TEOS Wafer) was placed on a platen, and the surface of the wafer was brought into contact with the polishing machine's pad (IC1010, DOW). Next, the sample slurry composition was supplied at a rate of 200 mL / min, and the polishing process was performed while rotating the platen and the polishing machine's pad. During this process, the rotation speed of the platen and the head were set to 67 rpm / 65 rpm, the polishing pressure to 2 psi, and the polishing time to 60 seconds. Meanwhile, the silicon oxide film thickness of the wafer was measured using ST5000 (Spectra Thick 5000ST, K-MAC). The results are shown in Table 20 below.

[0177] [Table 20]

[0178] As shown in Table 20 above, when using the slurry composition of the example, it was confirmed that the silicon oxide film removal rate was approximately 6 times or more compared to the slurry compositions of Comparative Examples 1 and 3. This is because, in the case of cerium oxide particles contained in the slurry composition of the example, the particle size is small, so the number of particles that effectively act on polishing is large relative to the content, and the Ce on the surface 3+ This is presumably because the high content (molar ratio and / or weight ratio) increases the chemical reactivity with the silicon oxide film surface.

[0179] Experimental Example 20. Defect Evaluation of Cerium Oxide Particles Figures 45 and 46 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 60 nm cerium oxide particles.

[0180] The surface analysis of the oxide wafer was performed by a full wafer scan method using an AIT-XP apparatus.

[0181] Referring to FIGS. 45 and 46, the surface of the oxide wafer polished using the CMP slurry composition containing cerium oxide particles according to the embodiment of the present invention was analyzed before and after CMP. As a result, it was found that the number of defects before CMP was 6, and the number of defects after CMP was aggregated to be 1. From this, it can be confirmed that the defects on the surface of the oxide wafer have decreased after CMP using the embodiment of the present invention, and furthermore, it can be confirmed that no scratch occurs during the CMP process. On the other hand, as a result of analyzing the surface of the oxide wafer polished using the CMP slurry composition containing cerium oxide particles of the prior art before and after CMP, it was confirmed that the number of defects after CMP increased to 64 compared to 34 defects before CMP. From this, it can be confirmed that the cerium oxide particles of the prior art caused scratches on the surface of the wafer. This suggests that since the particle size of the cerium oxide particles according to an embodiment of the present application is smaller than the particle size of the cerium oxide particles of the prior art, the probability of defects occurring on the surface of the oxide wafer to be polished is significantly reduced.

[0182] Experimental Example 21. Behavior of Oxide Polishing Rate and Analysis of Polishing Selectivity Ratio of Oxide Film / Polysilicon Film by Addition of Cationic Polymer Cerium oxide particles produced according to an embodiment of the present application and commercially available 60 nm-class cerium oxide particles of the prior art were added to deionized water, and after adjusting the pH to 5.8, a cationic polymer was added as shown in Table 21 below. Under the same polishing conditions as in Experimental Example 19, the polishing rate (Å / min) of the oxide film and the polishing rate (Å / min) of the polysilicon film were measured.

[0183]

Table 21

[0184] Referring to Table 21, in the slurries using commercially available 60 nm class cerium oxide particles in Comparative Examples 2 to 8, it was confirmed that the polishing rate of the silicon oxide film decreased significantly when 0.01% by weight of a cationic polymer was added. In contrast, in the slurry containing cerium oxide particles of the present invention, as seen in the results of Examples 2 to 8 in Table 21, it was confirmed that the oxide film polishing rate increased due to the inclusion of the cationic polymer. This is a characteristic not seen in conventional CMP slurries using cerium oxide particles.

[0185] Furthermore, comparing Example 1 in Table 21 with Examples 2-8, which include cationic polymers, it was confirmed that the polishing speed of the silicon oxide film increased, while the polishing speed of the polysilicon film decreased significantly. It was also confirmed that the polishing selectivity ratio of the oxide film to the polysilicon film satisfies the range of 2000 or less, within the range of approximately 200-900.

[0186] Furthermore, the content of cationic polymers in the samples of the examples and comparative examples in Table 21 was gradually increased, and the behavior of the oxide film polishing rate (Å / min) was investigated. Figure 47 shows the results of measuring the behavior of the oxide film polishing rate upon addition of cationic polymers to a CMP slurry composition containing cerium oxide particles, etc., according to one embodiment of the present invention.

[0187] Referring to Figure 47 and Table 21, it was observed that the polishing rate of the CMP slurry of the present invention increases with increasing content of cationic polymers, whereas in the case of conventional ceria slurries, the polishing rate gradually decreases when the concentration is increased to 0.001% or higher. This is because, in the case of conventional wet ceria slurries, cationic polymers are added simply to act as a pH buffer and stabilize the particles, so increasing the content of cationic polymers may hinder the polishing process by the polishing particles. In contrast, in the case of the CMP slurry of the present invention, it was found that the cationic polymers not only stabilize the particles but also act as a polishing accelerator.

[0188] [Modes for carrying out the invention]

[0189] The present invention will be described in more detail below. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein, but is defined only by the claims described later.

[0190] Furthermore, the terms used in this invention are used solely to describe specific embodiments and are not intended to limit the invention. Unless the context clearly indicates otherwise, singular expressions include plural expressions. Throughout this specification, when a component is described as "including," this does not exclude other components, unless otherwise specified, and means that other components may be included.

[0191] In this invention, "monodispersion" means that when cerium oxide particles are dispersed in a slurry, aggregation into secondary particles is suppressed, and the particle size of the primary particles is relatively maintained. This may mean that the particle size of the secondary particles (D50) determined 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, 2.0 times or less, or preferably 1.9 times or less, the size of the primary particles determined by TEM. Furthermore, when considering particle size distribution, this does not mean that the inclusion of relatively coarse-sized, unavoidable impurities is excluded.

[0192] In this invention, the term "transparent" means that when cerium oxide particles are dispersed in a slurry, the slurry composition appears transparent when observed visually. More specifically, it means that the average light transmittance for visible light is 50% or more, preferably 70% or more, and more preferably 80% or more. This further means that the cerium oxide particles of this invention suppress aggregation into secondary particles and maintain a relatively consistent particle size relative to the primary particles.

[0193] Abrasive compositions can be characterized according to their polishing speed (i.e., removal speed) and planarization efficiency. Polishing speed refers to the rate at which material is removed from the surface of the substrate and is usually expressed in units of length (thickness) per unit time (e.g., angstroms (Å) / minute). Specifically, the polishing surface, for example, the polishing pad, must first contact the "high points" of its surface and remove material to form a flat surface. A process that achieves a flat surface with less material removal is considered more efficient than a process that requires the removal of more material to achieve flatness.

[0194] Often, the removal rate of silicon oxide patterns can limit the rate of dielectric polishing steps in the STI process; therefore, a high removal rate of silicon oxide patterns is preferable for increasing device processing capacity. However, if the blanket removal rate is too fast, excessive polishing of oxide in the exposed trenches can lead to trench corrosion and increase device defects.

[0195] The present invention will be described in detail below.

[0196] The first aspect of the present invention is to provide cerium oxide particles 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% by weight, the light transmittance for light with a wavelength of 500 nm is 50% or more.

[0197] The following describes in detail one aspect of the present invention: cerium oxide particles for chemical and mechanical polishing.

[0198] Figure 1 shows an oxide film removal mechanism according to one embodiment of the present invention. As shown in Figure 1, Ce 3+ Unless the ions are activated, they cannot react smoothly with SiO2.

[0199] In one embodiment of the present invention, the particle size of the cerium oxide particles may be measured by X-ray diffraction (XRD) analysis (primary particles). In one embodiment of the present invention, the particle size of the cerium oxide particles measured by X-ray diffraction (XRD) analysis may be 11 nm or less. In other embodiment examples, the wavelength may be 10.8nm or less, 10.5nm or less, 10.2nm or less, 10nm or less, 9.5nm or less, 9.0nm or less, 8.5nm or less, 8.0nm or less, 7.5nm or less, 7.0nm or less, 6.5nm or less, 6.0nm or less, 5.5nm or less, 5.0nm or less, 4.5nm or less, or 4.0nm or less, and may also be 0.3nm or more, 0.5nm or more, 0.7nm or more, 1.0nm or more, 1.1nm or more, 1.2nm or more, 1.3nm or more, 1.4nm or more, 1.5nm or more, 1.6nm or more, 1.7nm or more, 1.8nm or more, 1.9nm or more, 2.0nm or more, 2.1nm or more, 2.2nm or more, 2.3nm or more, or 2.4nm or more. If the particle size of the cerium oxide particles is less than 0.3 nm, the crystallinity decreases, which can excessively hinder the polishing rate on the target film and reduce polishing efficiency. Conversely, if it exceeds 11 nm, there is a risk of a large number of surface defects such as scratches occurring. Furthermore, in one embodiment of the present invention, the average particle size of the cerium oxide particles measured by the X-ray diffraction (XRD) analysis may be characterized by being 0.5 to 10 nm, preferably 1 to 10 nm, and more preferably 2 to 9 nm.

[0200] In another embodiment of the present invention, the particle size of the cerium oxide particles may be measured by a transmission electron microscope (TEM) (primary particles). In another embodiment of the present invention, the particle size of the cerium oxide particles measured by a transmission electron microscope (TEM) may be 11 nm or less. In other embodiment examples, the wavelength may be 10.8nm or less, 10.5nm or less, 10.2nm or less, 10nm or less, 9.5nm or less, 9.0nm or less, 8.5nm or less, 8.0nm or less, 7.5nm or less, 7.0nm or less, 6.5nm or less, 6.0nm or less, 5.5nm or less, 5.0nm or less, 4.5nm or less, or 4.0nm or less, and may also be 0.3nm or more, 0.5nm or more, 0.7nm or more, 1.0nm or more, 1.1nm or more, 1.2nm or more, 1.3nm or more, 1.4nm or more, 1.5nm or more, 1.6nm or more, 1.7nm or more, 1.8nm or more, 1.9nm or more, 2.0nm or more, 2.1nm or more, 2.2nm or more, 2.3nm or more, or 2.4nm or more. If the particle size of the cerium oxide particles is less than 0.3 nm, the crystallinity decreases, which can excessively hinder the polishing rate on the target film and reduce polishing efficiency. Conversely, if it exceeds 11 nm, there is a risk of a large number of surface defects such as scratches occurring. Furthermore, in one embodiment of the present invention, the average particle size of the cerium oxide particles measured by the transmission electron microscope (TEM) may be characterized as being 0.5 to 10 nm, preferably 1 to 10 nm, and more preferably 2 to 9 nm.

[0201] In another embodiment of the present application, the particle size of the cerium oxide particles may be measured by small-angle X-ray scattering (SAXS) (primary particles). In another embodiment of the present application, the particle size of the cerium oxide particles measured by small-angle X-ray scattering (SAXS) may be 15 nm or less. In other concrete examples, the wavelength may be 14nm or less, 13nm or less, 12nm or less, 11nm or less, 10nm or less, 9.5nm or less, 9.0nm or less, 8.5nm or less, 8.0nm or less, 7.5nm or less, 7.0nm or less, 6.5nm or less, 6.0nm or less, 5.5nm or less, 4.5nm or less, or 4.0nm or less, and may also be 0.3nm or more, 0.5nm or more, 0.7nm or more, 1.0nm or more, 1.1nm or more, 1.2nm or more, 1.3nm or more, 1.4nm or more, 1.5nm or more, 1.6nm or more, 1.7nm or more, 1.8nm or more, 1.9nm or more, 2.0nm or more, 2.1nm or more, 2.2nm or more, 2.3nm or more, or 2.4nm or more. If the particle size of the cerium oxide particles is less than 0.3 nm, the crystallinity decreases, which can excessively hinder the polishing rate on the target film and reduce polishing efficiency. Conversely, if it exceeds 15 nm, there is a risk of a large number of surface defects such as scratches occurring. Furthermore, in one embodiment of the present invention, the average particle size of the cerium oxide particles measured by the small-angle X-ray scattering (SAXS) method may be characterized as being 0.5 to 15 nm, preferably 1 to 12 nm, and more preferably 1.5 to 10 nm.

[0202] In one embodiment of the present invention, the particle size of the cerium oxide particles in the slurry may be measured by dynamic light scattering (DLS) analysis (secondary particles). The dynamic light scattering analysis may be performed using analytical equipment known to the ordinary art, preferably using an Anton Parr particle size analyzer or a Malvern Zetasizer Ultra, but this is merely a non-limiting example.

[0203] In one embodiment of the present application, the particle size 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 application, the particle size 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, and may be 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 particle size of the secondary particles exceeds the above range, it means that a lot of aggregation of primary particles occurs in the slurry composition, in which case it is difficult to determine that it is a monodisperse slurry. If the particle size of the secondary particles is less than the above range, the polishing rate on the target film may be excessively inhibited and the polishing efficiency may decrease.

[0204] In one embodiment of the present invention, the cerium oxide particles may be characterized in that, when the particle size of the cerium oxide particles measured by a dynamic light scattering (DLS) particle size analyzer is a, and the particle size of the cerium oxide particles measured by a transmission electron microscope (TEM) is b, the following equation 2 is satisfied.

[0205] [Formula 2] a ≤ 2.2b

[0206] These characteristics serve as an indicator that the cerium oxide particles of the present invention exhibit low aggregation when dispersed in a slurry. If the coefficient of b exceeds 2.2, it means that a lot of aggregation occurs in the slurry, which may mean that the particle size becomes coarser, making it more difficult to suppress defects on the wafer surface during polishing.

[0207] In another embodiment of the present invention, the cerium oxide particles may be characterized in that, when the particle size of the cerium oxide particles measured by a dynamic light scattering (DLS) particle size analyzer is a, and the particle size of the cerium oxide particles measured by small-angle X-ray scattering (SAXS) is b, the following equation 3 is satisfied.

[0208] [Formula 3] a ≤ 2.5b

[0209] These characteristics serve as an indicator that the cerium oxide particles of the present invention exhibit low aggregation when dispersed in a slurry. If the coefficient of b exceeds 2.5, it means that a lot of aggregation occurs in the slurry, which may mean that the particle size becomes coarser, making it more difficult to suppress defects on the wafer surface during polishing.

[0210] In one embodiment of the present invention, Ce on the surface of the cerium oxide particles 3+ The content can be analyzed using XPS, for example, the theta probe base system from Thermo Fisher Scientific Co., Ltd. The Ce on the surface of the cerium oxide polishing particles. 3+ The content can be represented by the following chemical formula 1.

[0211] [Chemical formula 1] Ce 3+ Content (%)=(Ce 3+ Peak area) / [(Ce 3+ Peak area) + (Ce 4+ Peak Area)

[0212] In one example, when performing X-ray photoelectron spectroscopy (XPS) analysis on the surface of the cerium oxide particles, 3+ The XPS peaks indicating the Ce-O bond energy appear at 900.2–902.2 eV, 896.4–898.4 eV, 885.3–887.3 eV, and 880.1–882.1 eV. Specifically, when X-ray photoelectron spectroscopy (XPS) analysis is performed on the surface of the cerium oxide particles, Ce 3+ The XPS peaks indicating the Ce-O bond energy appear at the following points: a first peak at 900.2–902.2 eV, a second peak at 896.4–898.4 eV, a third peak at 885.3–887.3 eV, and a fourth peak at 880.1–882.1 eV.

[0213] In one embodiment of the present invention, the area of ​​the first peak may be 3% or more, or 4% or more, of the total XPS peak area; the areas of the second and fourth peaks may be 5% or more, 7% or more, or 10% or more, respectively; and the area of ​​the third peak may be 4% or more, 5% or more, or 6% or more.

[0214] Furthermore, in one embodiment of the present invention, during X-ray photoelectron spectroscopy (XPS) analysis, the sum of the XPS peak areas indicating the Ce-O bond energy on the surface of the cerium oxide particles is used. 3+ The ratio of the sum of XPS peak areas indicating the Ce-O bond energy is characterized to be 0.29 to 0.70. In another embodiment of the present invention, the ratio of the sum of XPS peak areas indicating the Ce-O bond energy on the surface of the cerium oxide particles is 3+ The ratio of the sum of XPS peak areas indicating the Ce-O bond energy was 0.18 or higher, 0.19 or higher, 0.192 or higher, 0.195 or higher, 0.198 or higher, 0.20 or higher, 0.202 or higher, 0.205 or higher, 0.208 or higher, 0.21 or higher, 0.22 or higher, 0.24 or higher, 0.25 or higher, 0.27 or higher, 0.28 or higher, 0.30 or higher, 0.32 or higher, or 0.35 or higher. 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. If it is less than the above range, a sufficient amount of Ce on the surface of the cerium oxide particles. 3+ If the presence of cerium oxide particles becomes impossible, it will be difficult to expect a sufficient increase in the polishing rate of the oxide film. Furthermore, if the range is exceeded, considering the oxidation state, it may become difficult to interpret the presence as cerium oxide particles.

[0215] In other words, in one embodiment of the present invention, during X-ray photoelectron spectroscopy (XPS) analysis, Ce is applied to the surface of the cerium oxide particles for chemical mechanical polishing. 3+It may contain 18 atomic% or more, 19 atomic% or more, 20 atomic% or more, 22 atomic% or more, 24 atomic% or more, 25 atomic% or more, 27 atomic% or more, 28 atomic% or more, 30 atomic% or more, 32 atomic% or more, or 35 atomic% or more, and may contain 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.

[0216] In the case of cerium oxide particles relating to one embodiment of the present application, Ce on the particle surface 3+ It exhibits a high content, which is presumed to be due to the particle synthesis process being carried out under acidic conditions in the liquid phase during the wet process, and thus Ce on the particle surface. 3+ When the content is relatively high, the oxide film polishing rate may improve.

[0217] In one embodiment of the present invention, the cerium oxide particles according to one embodiment of the present invention are distinguished from conventional polishing particles by having a Ce on the particle surface. 3+ The particles exhibit Raman spectral characteristics that suggest the presence of a large amount of the component. Specifically, the cerium oxide particles may be characterized by having two or more Raman peak spectra.

[0218] In one embodiment of the present invention, the cerium oxide particles are 455 cm². -1 ~460cm -1 The first Raman peak may be present in the band range of 586 cm². In another embodiment, the cerium oxide particles are present in 586 cm². -1 ~627cm -1 It may have a second Raman peak in the band range. In yet another embodiment, the cerium oxide particles have a second Raman peak in the band range of 712 cm⁻¹. -1 ~772cm -1 A third Raman peak may be present in the band range. Here, the band range may refer to the numerical range of the Raman shift, which is the X-axis of the Raman spectrum.

[0219] In one embodiment of the present application, the cerium oxide particles may be characterized in that the ratio of the first Raman peak intensity (A) to the second Raman peak intensity (B) (A / B) is 35 or less. The A / B ratio may preferably be 30 or less, more preferably 25 or less, and even more preferably 20 or less. The lower limit of the A / B ratio is not particularly limited, but may be 5 or more, 10 or more, or 15 or more. The second Raman peak is Ce 3+ This can be interpreted as a Raman shift resulting from an increase in the ratio of oxygen vacancies as the content increases, and therefore, the smaller the intensity ratio (A / B), the greater the Ce of the cerium oxide particles. 3+ This could mean an increase in content, which could promote the chemical polishing action using Si-O-Ce bonds with the oxide film wafer, suggesting that the polishing speed may be improved when using cerium oxide particles according to the embodiments of the present invention, despite having a finer particle size than conventional cerium oxide particles.

[0220] In one embodiment of the present application, the cerium oxide particles may be characterized by having a ratio (A / C) of 50 or less of the first Raman peak intensity (A) to the third Raman peak intensity (C). The A / C may preferably be 45 or less, and more preferably 43 or less. The lower limit of the A / C is not particularly limited, but may be 5 or more, 10 or more, or 15 or more.

[0221] As described above, the cerium oxide particles relating to one embodiment of the present invention are more Ce than conventional cerium oxide particles. 3+ Because it contains a high amount of [the substance], it is possible to provide a slurry composition that has a superior polishing speed compared to one containing cerium oxide particles, despite its small particle size, and it can also suppress the occurrence of polishing scratches.

[0222] In one embodiment of the present invention, Ce on the surface of the cerium oxide particles 3+ In relation to the content, it can be analyzed using electron energy loss spectroscopy (EELS) spectra, for example, if there are 2 or more Ce 4+It may be characterized by having an EELS peak indicating an oxidation state.

[0223] Cerium oxide particles (and / or slurry compositions containing them) can exhibit EELS spectra as shown in Figures 23-25.

[0224] The EELS spectrum of the cerium oxide particles according to one embodiment of the present application may include a first peak at 876.5–886.5 eV and a second peak at 894.5–904.5 eV, characterized in that the maximum intensity of the first peak is greater than the maximum intensity of the second peak. Such a feature is that of the cerium oxide particles. 3+ A higher content may indicate that it exhibits an EELS spectrum similar to that of trivalent cerium oxide.

[0225] In one embodiment of the present application, the spectrum may further be characterized by including a third peak in the range of 886.5–889.5 eV and a fourth peak in the range of 904.5–908.5 eV. In the case of the third and fourth peaks, peak differentiation by oxidation state is possible, and Ce 4+ By determining the area of ​​the peak interval that appears depending on the oxidation state, it is possible to distinguish between the cerium oxide particles of the present invention and conventional cerium oxide particles.

[0226] Furthermore, in one embodiment of the present invention, the sum of the total areas of the peaks in the spectrum (P t The ratio of the sum of the areas of the third peak interval (P1) to (P1 / P t The value may be 0.025 or less, and more preferably 0.024 or less, 0.022 or less, 0.018 or less, 0.015 or less, 0.012 or less, 0.011 or less, or 0.01 or less. In contrast, conventional cerium oxide particles show a minimum value of 0.03 or more, and this characteristic will be demonstrated by the experimental example below.

[0227] In one embodiment of the present invention, the sum of the total areas of the peaks in the spectrum (P tThe ratio of the sum of the areas of the third peak section (P1) and the sum of the areas of the fourth peak section (P2) to ((P1+P2) / P t The ratio of ((P1+P2) / P) may be 0.1 or less. Furthermore, the area ratio may preferably be 0.099 or less, 0.098 or less, 0.096 or less, 0.095 or less, 0.094 or less, 0.092 or less, or 0.090 or less. The ratio of cerium oxide particles according to one embodiment of the present application may, for example, mean the average ratio of the values ​​measured n times when the same sample is measured n times. The area ratio ((P1+P2) / P) t ) may, in other examples, be 0.01 or more, 0.012 or more, 0.014 or more, 0.016 or more, or 0.018 or more. When the ratio of the area is 0.1 or less, Ce is the total cerium oxide content on the surface of the cerium oxide particles. 3+ This could mean a high content, or a higher Ce 3+ The amount of this substance can enhance the polishing rate by promoting the chemical polishing action of the silicon oxide film through Si-O-Ce bonding.

[0228] The cerium oxide particles relating to one embodiment of the present invention are distinguished from conventional polishing particles by the presence of Ce on the particle surface. 3+ The XAFS (X-ray absorption fine structure) spectral features suggest that the component is present in large quantities. Specifically, the cerium oxide particles may be characterized by having two or more peaks in the XAFS spectrum.

[0229] In one embodiment of the present invention, cerium oxide particles (and / or a slurry composition containing them) can exhibit XAFS spectra as shown in Figures 9 and 10.

[0230] In one example, the cerium oxide particles may have a maximum light absorption coefficient of the first peak in the range of 5730 eV to less than 5740 eV when measured using XAFS spectroscopy, and the first peak is Ce 3+ It may also indicate the oxidation state.

[0231] In yet another embodiment, the cerium oxide particles may have a second peak with the maximum optical absorption coefficient in the range of 5740 eV to less than 5760 eV when measured using XAFS spectroscopy, and the second peak is Ce 4+ It may also indicate the oxidation state.

[0232] In one embodiment of the present application, the maximum light absorption coefficient (maximum value of the peak) of the first peak may be 0.1 to 0.4. In another embodiment of the present application, the maximum light absorption coefficient of the first peak may be 0.11 or more, 0.12 or more, 0.13 or more, 0.14 or more, 0.15 or more, 0.2 or more, or 0.25 or more, and may be 0.38 or less, 0.35 or less, 0.32 or less, or 0.30 or less.

[0233] In one embodiment of the present application, the maximum light absorption coefficient (maximum value of the peak) of the second peak may be less than 0.6. In another embodiment of the present application, the maximum light absorption coefficient of the second peak may be 0.11 or greater, 0.12 or greater, 0.13 or greater, 0.14 or greater, 0.15 or greater, 0.2 or greater, or 0.25 or greater, and may be 0.58 or less, 0.55 or less, 0.52 or less, or 0.50 or less.

[0234] If the light absorption coefficient of the first peak is less than 0.1 and the light absorption coefficient of the second peak exceeds 0.6, Ce is added to the total weight of the cerium oxide surface. 3+ This means that the weight will decrease, which could further hinder the polishing speed.

[0235] In one embodiment of the present application, the ratio (A1 / A2) of the area of ​​the first peak (A1) to the area of ​​the second peak (A2) shown in the XAFS spectrum may be 0.03 or more. The area ratio of the peaks (A1 / A2) may be 0.03 or more, 0.05 or more, 0.07 or more, 0.09 or more, or 0.1 or more, more preferably 0.11 or more, and even more preferably 0.12 or more. That is, Ce as shown by the XAFS (X-ray absorption fine structure) spectrum3+ The peak areas A3 and Ce are shown. 4+ For the sum of the peak areas A4 that show, Ce 3+ The ratio of the peak area A3 to the peak area A3 (A3 / (A3 + A4)) may be 0.1 or more (10% or more). If the weight ratio is less than 0.03, Ce on the surface of the cerium oxide particles 4+ Compared to the content of Ce 3+ Insufficient content may lead to a decrease in polishing speed.

[0236] In one embodiment of the present invention, photoelectron spectroscopy analysis can be performed on the cerium oxide particles, and specifically, ultraviolet photoelectron spectroscopy (UPS) analysis using light in the UV region can be performed. Photoelectron spectroscopy techniques are traditionally divided into X-ray photoelectron spectroscopy (XPS), which uses single-wavelength light in the X-ray region, and ultraviolet photoelectron spectroscopy (UPS), which uses light in the UV region. XPS is a technique that uses X-rays with an energy of about 1000 to 1500 eV to analyze electrons emitted mainly from the core level of atoms inside the sample, and investigates the type, chemical state, and concentration of elements in the sample. Many commercially available equipment is sold, and the analysis method and usage are widely known. In contrast, UPS uses extreme ultraviolet light of about 10 to 20 eV. This technique uses UV light to emit electrons from the valence electron region of a sample, allowing researchers to investigate the diverse states that electrons directly participating in chemical bonds can have within a solid. In particular, so-called angle-resolved UPS (ARUPS / ARPES) can directly measure the band structure of single-crystal samples, making such measurements crucial for understanding the unique properties of materials. It can be used to grasp the physical properties of materials such as high-temperature superconductors and colossal magnetoresistance materials. When a solid sample is illuminated with light having an energy of hv, electrons gain kinetic energy while satisfying the laws of conservation of energy and momentum. The kinetic energy of the electrons that leave the sample at this time is given as follows.

[0237] E kin =hv-φ-|E b |

[0238] Here, E kin φ is the kinetic energy of the ejected electron, φ is the work function of the sample, E b is the binding energy when the emitted electron is bound to the sample. By measuring the intensity due to the kinetic energy of the emitted electron from the outside using an electron energy analyzer, the density of states due to the binding energy of the electrons inside the sample can be determined. Therefore, referring to the above equation, the binding energy can be derived from the measured kinetic energy, and in this case, the work function φ of the sample is given by the hv value of the source energy and the Fermi level (E F ) and vacuum level (E cutoff It can be expressed using ).

[0239] φ = hv - |E f -E cutoff |

[0240] When the UPS result values ​​are plotted on a graph, zero on the x-axis represents the Fermi level (E) of the sample. F ) shows E cutoffThis is a numerical value expressed by the vacuum level. hv is the source energy used to emit ultraviolet light and indicates the energy of the incident light, but helium (He) can generally be used as the source.

[0241] In one embodiment of the present invention, the band structure of cerium oxide may differ depending on the particle size. As the particle size decreases, the difference in energy levels between the sample orbitals gradually increases, and a high energy band gap can be achieved. Conversely, as the particle size increases, the difference in energy levels gradually decreases, and a low energy band gap is achieved. Therefore, as described above, the smaller the particle size, the greater the energy gap between the valence band and the conduction band, and the Fermi level (E F The energy (eV) of the derived work function can be increased by changing the values ​​of the vacuum level and the vacuum level.

[0242] In one embodiment of the present invention, the cerium oxide particles may be characterized in that, during UPS analysis, the maximum number of photoelectrons (Counts) emitted per second is in the range of kinetic energy 10 eV or less. Such a characteristic is in contrast to that of conventional ceria particles. The maximum number of photoelectrons (Counts) emitted per second may be in the range of kinetic energy 6 to 10 eV, or 7 to 10 eV, and preferably in the range of 8 to 10 eV.

[0243] In one embodiment of the present invention, the work function value of the cerium oxide particles, as measured by UPS, may be in the range of 2.5 eV or higher. Preferably, the work function value is in the range of 2.7 eV or higher, and more preferably, in the range of 3.0 eV or higher. The upper limit of the work function value is not particularly limited and may be less than 10 eV, 9 eV or less, or 8 eV or less. The fact that the work function value satisfies the above range is a characteristic that is in contrast to conventional cerium oxide particles, and means that the particle size of the cerium oxide particles dispersed in the slurry is small, which indicates very low cohesiveness. Because of these characteristics of low cohesiveness and monodispersibility, when the cerium oxide particles according to one embodiment of the present invention are used in a chemical mechanical polishing slurry, it is expected that the number of particles in contact with the wafer can be maximized, the oxide film polishing speed can be increased, and at the same time, since the particle size itself is fine, defects on the wafer surface can be minimized.

[0244] In one embodiment of the present invention, when the specific surface area was measured for 1 g of powder consisting of cerium oxide particles, the BET surface area value was 50 m². 2 It may be less than or equal to / g. In another embodiment, the BET surface area value is 49m 2 / g or less, 48m 2 / g or less, 47m 2 / g or less, 46m 2 / g or less, 45m 2 / g or less, 44m 2 / g or less, 43m 2 / g or less, preferably 42m 2It may be less than / g. This shows a different trend from conventional cerium oxide particles, which have a larger BET surface area value as the particle size decreases. This can be inferred to be because cerium oxide particles synthesized by self-assembly synthesis methods such as the sol-gel method and bottom-up method have a smaller specific surface area and pore volume than cerium oxide particles produced by other synthesis methods, and in particular, the ratio of -OH functional groups present on the surface of the cerium oxide particles is low. Furthermore, it can be predicted that the particles have a finer particle size than conventional cerium oxide particles, and when the particles are analyzed by BET under the same conditions as 1.0 g of powder, the powder sample is aligned at a higher density than the conventional cerium oxide particles of Comparative Example 1, resulting in a smaller BET surface area value.Therefore, it can be confirmed that the cerium oxide particles according to the examples of the present invention have a finer particle size than the conventional 10 nm class cerium oxide particles of Comparative Example 1, and that the above results indicate that when the cerium oxide particles according to the examples of the present invention are compared with conventional cerium oxide particles, they have a finer particle size, and at the same time, Ce on the particle surface 4+ And Ce compared to the content of -OH functional groups 3+ This can be understood in the same context as the tendency to exhibit surface chemical properties such as high content.

[0245] In one embodiment of the present application, the apparent density of the cerium oxide particles, as measured by the static method, may be 2.00 to 5.00 g / ml, preferably 2.00 to 4.00 g / ml, and more preferably 2.00 to 3.00 g / ml.

[0246] Another embodiment of the present application may be characterized in that the apparent density of the cerium oxide particles, as measured by the Tab method, is 2.90 to 5.00 g / ml, preferably 3.00 to 5.00 g / ml, and more preferably 3.20 to 5.00 g / ml.

[0247] When a slurry containing cerium oxide particles with an apparent density exceeding 5.00 g / ml dispersed in water is used for polishing, the coarse particle sizes of primary and secondary particles may cause scratches on the polished surface. Furthermore, in one embodiment of the present invention, if cerium oxide particles with a density of less than 2.00 g / ml are used, the polishing speed becomes extremely small as the particle size of the primary particles decreases, making it difficult to obtain a sufficient polishing effect. Therefore, it is preferable to maintain an apparent density of 2.00 g / ml or higher even with a small particle size of 10 nm or less. Accordingly, it can be seen that the cerium oxide particles according to one embodiment of the present invention have a relatively high apparent density compared to conventional cerium oxide particles, despite their fine particle size, and there is a difference. It can be expected that such characteristics may have a certain effect on the polishing speed of the oxide film.

[0248] In one embodiment of the present invention, when the photoluminescence (PL) is measured at a wavelength of 325 nm using an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight as a reference, the maximum intensity of the first peak (λ1) at wavelengths of 435-465 nm may be in the range of 0.1-30, 0.2-20, 0.3-10, or 0.5-7. In the case of conventional commercially available coarse cerium oxide particles, the maximum peak intensity exceeds 30 under the same conditions, but the aggregation in the slurry is also strong, which may mean that emission occurs more strongly than transmission.

[0249] In one embodiment of the present invention, the maximum intensity of the second peak (λ2) at a wavelength of 510-540 nm is shown in the range of 0.1-10, 0.1-7.5, 0.1-5, or 0.1-3, based on an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight. In the case of conventional commercially available coarse cerium oxide particles, the maximum peak intensity exceeds 10 under the same conditions, but the aggregation in the slurry is also strong, which may mean that emission occurs more strongly than transmission.

[0250] In one embodiment of the present invention, the characteristics of the cerium oxide particles can be determined by measuring the photoluminescence (PL) at a wavelength of 325 nm in an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight. Specifically, in one embodiment of the present invention, when analyzing fluorescence spectroscopy performed at an excitation wavelength of 325 nm, an excitation peak (λ) is observed at wavelengths of 310-335 nm. exc ) appears, and a first peak (λ1) may appear at wavelengths of 435-465 nm, and a second peak (λ2) may appear at wavelengths of 510-540 nm. The excitation peaks indicate peaks with respect to the excitation wavelength, and the first peak is Ce 3+ This indicates that the second peak is Ce 4+ This could be interpreted as indicating that.

[0251] In one embodiment of the present invention, when the photoluminescence (PL) is measured at a wavelength of 325 nm for an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight, an excitation peak (λ) at wavelengths of 310-335 nm is observed. exc The intensity ratio of the first peak (λ1) at wavelengths of 435-465 nm to (λ1 / λ) exc ) may be less than 30, preferably 27 or less, 25 or less, more preferably 23 or less, even more preferably 18 or less, 15 or less, and even more preferably 10 or less.

[0252] In one embodiment of the present application, the intensity ratio (λ1 / λ2) of the first peak (λ1) to the second peak (λ2) at wavelengths of 510 to 540 nm may be 4 or more, preferably 5 or more, more preferably 5.5 or more, even more preferably 6 or more, and may be 20 or less, preferably 18 or less, more preferably 15 or less, even more preferably 12 or less, and even more preferably 10 or less.

[0253] The cerium oxide particles relating to one embodiment of the present invention have the excitation peak (λ exc The intensity ratio of the first peak (λ1) to (λ1 / λ) exc) and the intensity ratio (λ1 / λ2) of the first peak (λ1) to the second peak (λ2) satisfies within the above range, the surface of the cerium oxide particles has a high content of Ce 3+ Despite containing Ce, aggregation into secondary particles in the dispersion is very low, and good light transmission is obtained, along with the Ce on the particle surface. 3+ This indicates that it has the characteristic of having a relatively high content. In the case of cerium oxide particles of the present invention, when used in a chemical mechanical polishing slurry, the Ce on the particle surface 3+ Although the content is high, the particles themselves are fine and aggregate in the slurry is very low. As a result, the chemical polishing rate due to the Si-O-Ce bond between the cerium oxide particles and the oxide film substrate is increased, and the oxide film polishing rate is improved.

[0254] In one embodiment of the present invention, the yellowness of the dispersion containing cerium oxide particles can be evaluated by the L*a*b* color system, where L*a*b is defined by the CIE1976 L*a*b* color space established by the CIE (Commission Internationalable de Eclairage: International Commission on Illumination) in 1976. This color space is a color space having quantities L*, a*, and b* determined by the following equations in a Cartesian coordinate system.

[0255] L*=116(Y / Y0) 1 / 3 -16 a* = 500[(X / X0) 1 / 3 -(Y / Y0) 1 / 3 ] b*=200[(Y / Y0) 1 / 3 -(Z / Z0) 1 / 3 ] (However, X / X0, Y / Y0, Z / Z0 > 0.008856, X, Y, and Z are tristimulus values ​​of the object's color, and X0, Y0, and Z0 are tristimulus values ​​of the light source illuminating the object's color, and are standardized to Y0 = 100.)

[0256] L* represents brightness and is also called the "luminosity index." a* and b* represent hue and saturation and are also called the "chromaticity index." In the L*a*b* color system, a larger L* value indicates a color closer to white, and a smaller L* value indicates a color closer to black. Furthermore, a larger a* value towards the positive side indicates a stronger reddish color, while a smaller a* value (larger towards the negative side) indicates a stronger greenish color. Similarly, a larger b* value towards the positive side indicates a stronger yellowish color, while a smaller b* value (larger towards the negative side) indicates a stronger blueish color. Finally, if both a* and b* values ​​are 0, it means the color is achromatic.

[0257] In one embodiment of the present invention, when the color of an aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight is expressed in the L*a*b* color system, the L* value may be 80 or higher, preferably 85 or higher, more preferably 90 or higher, even more preferably 95 or higher, and even more preferably 98 or higher. If the L* value is smaller than the above range, it may mean that the particle growth of the cerium oxide polishing particles has progressed too far, and there are many coarse particles that cause defects in the wafer during polishing. Furthermore, the L* value may be characterized by being 100 or less, more preferably 99.9 or less.

[0258] In one embodiment of the present application, the b* value may be 8 or more, preferably 10 or more, more preferably 11 or more, and may be characterized by being in the range of less than 30, preferably 25 or less, more preferably 20 or less, and even more preferably 15 or less. If the b* value is smaller than the above range, the necessary chemical reaction may not be obtained during polishing, and the fine irregularities on the polished surface may not be polished smoothly.

[0259] In one embodiment of the present invention, the a* value may be less than -3, preferably -4 or less, more preferably -5 or less, and may be characterized by being in the range of -8 or more, more preferably -7 or more.

[0260] Therefore, when the color of the aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight is expressed in the L*a*b* color system, if the respective values ​​are within the aforementioned range, the dispersion can be observed in a transparent yellow state, and it is presumed that the darker the yellow color of the dispersion, the greater the polishing speed. In particular, the cerium oxide particles according to one embodiment of the present application, despite their fine particle size, when included in a chemical mechanical polishing slurry, the Ce on the cerium oxide surface 3+ Due to the high ratio of [unclear], the oxide film polishing speed is remarkably high, and the fine particles minimize defects on the wafer surface. When expressed in the L*a*b* color system, the fact that each value is within the aforementioned range, or particularly high in yellowness, indicates that the Ce on the surface of the cerium oxide particles is higher compared to conventional cerium oxide particles. 3+ This can be interpreted as meaning that the ratio is relatively very high.

[0261] In one embodiment of the present invention, when an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is centrifuged for 30 minutes under a centrifugal force of 4265G (6,000 rpm), the settling rate of the cerium oxide particles may be 25% by weight or less. In another embodiment, the settling rate may be 20% by weight or less, 15% by weight or less, 10% by weight or less, and more preferably 5% by weight or less.

[0262] Furthermore, in one embodiment of the present invention, when an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is centrifuged at a centrifugal force of 2100 G (3,200 rpm) for 10 minutes, the settling rate of the cerium oxide particles may be 0.6% by weight or less. In another embodiment, the settling rate may be 0.55% by weight or less, 0.5% by weight or less, 0.45% by weight or less, and more preferably 0.4% by weight or less.

[0263] Furthermore, in another embodiment of the present application, when an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is centrifuged at a centrifugal force of 3300G (4,000 rpm) for 30 minutes, the settling rate of the cerium oxide particles may be 5.0% by weight or less. In yet another embodiment, the settling rate may be 4.8% by weight or less, 4.5% by weight or less, 4.2% by weight or less, and more preferably 4.0% by weight or less.

[0264] Furthermore, in another embodiment of the present application, when an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is centrifuged for 30 minutes under a centrifugal force of 26188G (12,000 rpm), the settling rate of the cerium oxide particles may be 45.0% by weight or less. In yet another embodiment, the settling rate may be 42% by weight or less, 40% by weight or less, 38% by weight or less, and more preferably 35% by weight or less.

[0265] Furthermore, in another embodiment of the present application, when an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is centrifuged for 30 minutes under a centrifugal force of 39282G (18,000 rpm), the settling rate of the cerium oxide particles may be 90.0% by weight or less. In another embodiment, the settling rate may be 80% by weight or less, 70% by weight or less, 65% by weight or less, and more preferably 60% by weight or less.

[0266] In one embodiment of the present application, the viscosity of the aqueous dispersion may be 0.3 to 2.0 mPa·s, 0.5 to 1.8 mPa·s, 0.55 to 1.5 mPa·s, or 0.6 to 1.2 mPa·s, and in one preferred embodiment, centrifugation can be performed under conditions of 0.65 to 1.2 mPa·s.

[0267] When centrifugal separation is performed under conditions ranging from weak to severe centrifugal force, if the settling rate of the cerium oxide particles is below the above range, it can be said that the cerium oxide particles according to one embodiment of the present invention have a finer particle size and are monodisperse compared to conventional cerium oxide particles. Therefore, in the chemical mechanical polishing process, monodisperse particles come into contact with the wafer, and an increase in the number of contacting particles can be expected to improve the oxide film polishing speed. Furthermore, it can be seen that polishing with the embodiment of the present invention having a fine particle size can reduce the occurrence rate of polishing defects.

[0268] In one embodiment of the present invention, the cerium oxide primary particles may be one or more selected from the group consisting of spherical, cube, tetragonal, orthorhombic, rhombohedral, monoclinic, hexagonal, triclinic, and cuboctahedron shapes, but preferably spherical particles.

[0269] In one embodiment of the present invention, the cerium oxide particles can be produced by a method of growing particles through chemical synthesis, preferably a bottom-up method. Methods for synthesizing the cerium oxide particles include, but are not limited to, the sol-gel method, supercritical reaction, hydrothermal reaction, or coprecipitation method. The bottom-up method is a type of chemical synthesis that has recently attracted attention, in which starting materials of atoms or molecules are grown into nanometer-sized particles through chemical reactions.

[0270] In one embodiment of the present application, the abrasive 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 include colloidal cerium oxide particles, precipitated cerium oxide particles, or condensed polymerized cerium oxide particles.

[0271] In one embodiment of the present invention, the wet cerium oxide particles also preferably have defects on their surface. Without attempting to tie to any particular theory, grinding of cerium oxide particles can result in defects on the surface of the cerium oxide particles, and such defects also affect the performance of the cerium oxide particles in the chemical mechanical polishing composition. In particular, cerium oxide particles can be fractured during grinding, exposing less favorable surface conditions. This process is known as relaxation, in which atoms around the surface of the cerium oxide particles, which have limited reconfiguration ability and limited ability to return to a more favorable state, cause defects to form on the particle surface.

[0272] In one embodiment of the present invention, in the generation of secondary particles of abrasive material, each solvent has its own dielectric constant value. The dielectric constant of the solvent affects the aggregation and growth of nuclei by changing the surface energy and surface charge during nucleation and crystal growth in powder synthesis, which in turn affects the size and shape of the powder. The dielectric constant of the solvent and the surface potential (zeta potential) of particles dispersed in the solvent are proportional to each other. If the zeta potential is low, the surface repulsive force between fine particles or between nuclei generated by the reaction is small, resulting in an unstable state where aggregation between fine particles or between nuclei can occur at a very rapid rate. In this case, since the magnitude of the surface repulsive force is similar between fine particles or between nuclei, aggregation of uniform size is possible. The aggregated secondary particles in this way will grow into relatively large particles through particle merging processes such as strong aggregation of primary fine particles and nuclei and Oswald ripening, depending on reaction conditions such as temperature and concentration.

[0273] A second aspect of the present invention provides a chemical mechanical polishing slurry composition comprising cerium oxide particles and a solvent, characterized in that an aqueous dispersion in which the content of the cerium oxide particles is adjusted to 1.0% by weight has a light transmittance of 50% or more for light with a wavelength of 500 nm.

[0274] While detailed explanations of the parts that overlap with the first aspect of this application will be omitted, the content explained in the first aspect of this application can be similarly applied to the second aspect even if that explanation is omitted.

[0275] The following describes in detail the chemical mechanical polishing slurry composition relating to the second aspect of this application.

[0276] A chemical mechanical polishing slurry composition according to one embodiment of the present application comprises cerium oxide particles and a solvent.

[0277] In one embodiment of the present invention, the cerium oxide particles contained in the slurry as polishing particles may have a positive zeta potential value, preferably 1 to 80 mV, 5 to 60 mV, or 10 to 50 mV in the pH range of 2 to 8. When the zeta potential value of the cerium oxide particles is positive and the polarity of the silicon oxide film surface is negative, the polishing efficiency can be increased by the attractive force between the cerium oxide particles and the silicon oxide film surface.

[0278] In one embodiment of the present invention, the cerium oxide particles have a lower hardness than silica particles or alumina particles, but due to the chemical polishing mechanism by which Si-O-Ce bonds are formed between silica and cerium, the polishing speed of silicon-containing surfaces such as glass and semiconductor substrates is very fast, which is advantageous for polishing semiconductor substrates.

[0279] In one embodiment of the present application, the content of the precursor substance in the slurry composition may be 300 ppm or less by weight. In another embodiment of the present application, the content of the precursor substance in the slurry composition may be 200 ppm or less, 150 ppm or less, 100 ppm or less, 75 ppm or less, 50 ppm or less, 25 ppm or less, 15 ppm or less, 10 ppm or less, 7.5 ppm or less, 5 ppm or less, 2.5 ppm or less, 2 ppm or less, 1.75 ppm or less, 1.5 ppm or less, 1.25 ppm or less, 1 ppm or less, 0.75 ppm or less, or 0.5 ppm or less by weight. The slurry composition may substantially not contain any precursor substance. Here, the precursor substance may include cerium precursor substance, basic substance, solvent, and ammonia, which are precursor substances used and generated in the process of producing cerium oxide particles in a wet process.

[0280] In one embodiment of the present application, the chemical mechanical polishing slurry composition may be characterized by containing cerium oxide particles in an amount of 5% by weight or less based on the total weight of the composition. In another embodiment of the present application, the chemical mechanical polishing slurry composition may contain cerium oxide particles in an amount of 4% by weight or less, 3% by weight or less, 2% by weight or less, 1.5% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.4% by weight or less, 0.3% by weight or less, 0.2% by weight or less, less than 0.2% by weight, 0.19% by weight or less, 0.15% by weight or less, 0.12% by weight or less, 0.10% by weight or less, 0.09% by weight or less, or 0.07% by weight or less based on the total weight of the composition, or 0.001% by weight or more or 0.001% by weight or more. The chemical mechanical polishing slurry composition of the present invention may also be characterized in that, even when using a slurry with the same polishing rate, a high oxide film polishing efficiency can be achieved even when adding a smaller amount than the cerium oxide particles relative to the total weight of the chemical mechanical polishing slurry composition.

[0281] In one embodiment of the present invention, the aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight may be characterized by having an average light transmittance of 50% or more or 60% or more for light with a wavelength of 450 to 800 nm, preferably an average light transmittance of 70% or more, more preferably 80% or more, and even more preferably 90% or more. In another embodiment of the present invention, the light transmittance for light with a wavelength of 500 nm may be characterized by being 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, or 80% or more. Furthermore, the light transmittance for light with a wavelength of 600 nm may be characterized by being 75% or more, 80% or more, 85% or more, or 90% or more. In addition, the light transmittance for light with a wavelength of 700 nm may be characterized by being 87% or more, 90% or more, 93% or more, or 95% or more. The fact that the light transmittance of the slurry composition satisfies the aforementioned range means that the primary particle size of the cerium oxide particles in one embodiment of the present invention is small, and that aggregation into secondary particles is less than that of conventional ceria particles. With such low aggregation, the dispersion stability is high, allowing for uniform particle distribution, and since more particles come into contact with the wafer, the oxide film polishing speed is excellent. Furthermore, because the particles themselves are fine, it can be easily inferred that when a film to be polished is polished using a slurry composition containing these particles, the probability of defects such as scratches occurring on the surface decreases. In other words, for cerium oxide particles of 10 nm or less based on primary particles, it can be predicted that the higher the light transmittance in the visible light region, the better the silicon oxide film polishing speed.

[0282] In one embodiment of the present invention, when Fourier-transformation infrared (FT-IR) spectroscopy is performed on the powder consisting of cerium oxide particles, the 3000 cm⁻¹ in the spectrum identified by the FT-IR spectroscopy is -1 ~3600cm -1 Within this range, the infrared transmittance of the powder consisting of cerium oxide particles may be 90% or more, or 100% or less, 97% or less, or 95% or less. Furthermore, in one embodiment of the present application, 720 cm -1~770cm -1 The infrared transmittance of the powder may be characterized as 96% or less within the range, and may be 85% or more, 88% or more, more preferably 90% or more, and even more preferably 92% or more. The FT-IR spectrum at 3000 cm² -1 ~3600cm -1 Within this range, the fact that the infrared transmittance has a value within the aforementioned range may mean that the band due to the OH group is relatively weak, which indicates a difference from the FT-IR spectrum of a powder consisting of cerium hydroxide particles. Furthermore, the FT-IR spectrum of a powder consisting of cerium oxide particles according to one embodiment of the present application at 720 cm⁻¹ -1 ~770cm -1 The presence of a peak in the range indicating infrared transmittance within that range may mean that Ce-O stretching occurs within that range, which may mean that particles produced according to one embodiment of the present invention exhibit the characteristics of cerium oxide particles.

[0283] In one embodiment of the present application, the chemical mechanical polishing slurry composition may have a pH of 10 or less, preferably 1 to 9, 1 to 8, or 2 to 7, from the viewpoint of dispersion stability and polishing efficiency. More specifically, if the pH is less than 1, the removal rate of the silicon oxide film decreases sharply and undesirable polishing properties may be exhibited, and if the pH exceeds 10, undesirable polishing properties may be exhibited, or the pH stability and dispersion stability may decrease, leading to aggregation, which may result in micro-scratch and defects.

[0284] In one embodiment of the present application, the chemical mechanical polishing slurry composition may contain one or more acidic or basic pH adjusters and buffers that can adjust the pH of the composition, taking into consideration the final pH of the composition, the polishing speed, the polishing selectivity ratio, etc. As the pH adjuster for adjusting the pH, one 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 application, the pH adjuster may be an acidic pH adjuster or a basic pH adjuster for achieving an appropriate pH.

[0285] In one embodiment of the present application, examples of the pH adjusting agent 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; imidazoles; alkylamines; alcoholamines; quaternary amine hydroxides; ammonia; or combinations thereof. In particular, the pH adjusting agent may be triethanolamine, tetramethylammonium hydroxide (TMAH or TMAOH), or tetraethylammonium hydroxide (TEAH or TEA-OH). Furthermore, examples of the pH adjusting agent include at least one selected from the group consisting of ammonium methyl propanol (AMP), tetramethylammonium hydroxide (TMAH), potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, triethanolamine, tromethamine, and niacinamide. Preferably, the pH adjusting agent may be triethanolamine or aminobutyric acid.

[0286] In one embodiment of the present application, the solvent can be any solvent used in chemical mechanical polishing slurry compositions, for example, deionized water can be used, but the present invention is not limited thereto. Preferably, ultrapure water can be used. The amount of the solvent may be the remaining amount of the chemical mechanical polishing slurry composition excluding the amount of cerium oxide particles and other additional additives. In one embodiment of the present application, the solvent may include water (e.g., deionized water) as an aqueous support and may include one or more water-miscible organic solvents. Examples of usable organic solvents may include alcohols (e.g., propenyl alcohol, isopropyl alcohol, ethanol, 1-propanol, methanol, 1-hexanol, etc.); aldehydes (e.g., acetylaldehyde, etc.); ketones (e.g., acetone, diacetone alcohol, methyl ethyl ketone, etc.); esters (e.g., ethyl formate, propyl formate, ethyl acetate, methyl acetate, methyl lactate, butyl lactate, ethyl lactate, etc.); sulfoxides (e.g., dimethyl sulfoxide (DMSO)); ethers (e.g., tetrahydrofuran, dioxane, diglyme, etc.); amides (e.g., N,N-dimethylformamide, dimethylimidazolidinone, N-methylpyrrolidone, etc.); polyhydric alcohols and their derivatives (e.g., ethylene glycol, glycerol (glycerin), diethylene glycol, diethylene glycol monomethyl ether, etc.); and nitrogen-containing organic compounds (e.g., acetonitrile, amylamine, isopropylamine, dimethylamine, etc.).

[0287] In one embodiment of the present application, the abrasive composition may further include one or more other additives. The abrasive composition includes a surfactant and / or rheological modifier containing a thickener and a coagulant (e.g., a polymer rheological modifier such as a urethane polymer), a biocide (e.g., KATHON TM This may include LX, etc. Suitable surfactants include, for example, cationic surfactants. This includes surfactants, anionic surfactants, anionic polymer electrolytes, nonionic surfactants, amphoteric surfactants, fluorinated surfactants, and mixtures thereof.

[0288] In one embodiment 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.

[0289] The chemical mechanical polishing slurry composition may be provided in the form of a one-component slurry composition containing all components, such as cerium oxide particles, a solvent, and other additives, or, if necessary, in the form of a two-component or three-component slurry composition in which these components are stored separately in two or three or more containers and then mixed at or near the time of use. The choice of such provisioning form and combination of stored components is within the knowledge of those skilled in the art, and the overall polishing characteristics and polishing speed can be adjusted by changing the mixing ratio.

[0290] In one embodiment of the present application, the chemical mechanical polishing slurry composition is characterized by having a silicon oxide film polishing rate of 1,000 Å / min or more, preferably 2,000 Å / min or more, and more preferably 3,000 Å / min or more. Basically, the higher the oxide film polishing rate, the better, and there is no particular upper limit, but it 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 embodiment of the present application, even in the range where the cerium oxide particle content is low, the particle size is small, so the number of particles contained is larger compared to conventional slurry compositions containing cerium oxide particles, resulting in a high surface Ce 3+ The Si-O-Ce bond increases depending on the content, which significantly improves the polishing speed of the silicon oxide film.

[0291] In one embodiment of the present application, the chemical mechanical polishing slurry composition may have an oxide film / polysilicon film polishing selectivity ratio of 50 or more, 100 or more, 150 or more, or 200 or more, and may be characterized by having an oxide film / polysilicon film polishing selectivity ratio 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 the oxide film / polysilicon film selectivity ratio, it cannot be ruled out that a selectivity ratio of 3,000 or more can also be achieved by appropriately adjusting the content of cationic polymers.

[0292] When cerium oxide is used as an abrasive, unlike mechanical polishing which only removes the hydrated layer formed on the surface, the high reactivity between cerium oxide and silicon oxide causes a Si-O-Ce chemical bond to form, and the cerium oxide polishes the silicon oxide film by removing clumps of silicon oxide from the surface of the silicon oxide film. Furthermore, the cerium oxide powder according to the embodiment of the present invention has low strength due to its small particle size, which has the advantage of providing excellent broad-area flatness during polishing, while also solving the problem of micro-scratch formed by large particles.

[0293] Another aspect of the present invention provides a chemical mechanical polishing slurry composition characterized by comprising cerium oxide particles; a solvent; and a cationic polymer.

[0294] In one embodiment of the present invention, the oxide film polishing rate may increase depending on the content of the cationic polymer. 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 explained in detail below.

[0295] In one embodiment of the present invention, the cationic polymer can play two roles in the chemical mechanical polishing slurry composition of the present invention. First, the cationic polymer can act as a stabilizer of the slurry composition, and by acting as a pH buffer, it can ensure particle dispersibility and dispersion stability. Second, the cationic polymer of the present invention can act as a polishing accelerator for oxide films. In conventional polishing slurries, cationic polymers are added to improve dispersion stability, or to remove field oxide films during step removal. Cationic polymers were used to protect the oxide film, and to obtain these properties, it was necessary to sacrifice some of the oxide film polishing speed. In contrast, the cationic polymer added to the polishing slurry of the present invention not only improves dispersion stability, but also increases the overall polishing speed of the oxide film as the amount of cationic polymer added increases.

[0296] In one embodiment of the present application, the content of the cationic polymer may be 0.001% by weight or more, 0.002% by weight or more, 0.003% by weight or more, 0.004% by weight or more, or 0.005% by weight or more, based on the total weight of the chemical mechanical polishing slurry composition, and may also be 1% by weight or less, 0.5% by weight or less, 0.1% by weight or less, 0.05% by weight or less, 0.03% by weight or less, or 0.01% by weight or less. If the content of the cationic polymer is less than 0.001% of the total weight of the chemical mechanical polishing slurry composition, the content is too low to adequately perform its role as a polishing accelerator and cannot affect the polishing speed. Conversely, if it exceeds 1%, the added cationic polymer may interfere with the polishing process of cerium oxide and may actually reduce the polishing speed.

[0297] In one embodiment of the present invention, the cationic polymer may be characterized by being a polymer or copolymer containing an amine group or an ammonium group. For example, in one embodiment of the present application, the cationic polymer may be characterized by being polydiallyldimethylammonium chloride, polyallylamine, polyethyleneimine, polydiallylamine, polypropyleneimine, polyacrylamide-co-diallydimethylammonium chloride, polyacrylamide, or a combination thereof, preferably polydiallyldimethylammonium chloride, polyallylamine, polyethyleneimine, polyacrylamide-co-diallydimethylammonium chloride, polyacrylamide, or poly(trimethylammonioethyl methacrylate) It may also be characterized by being a methacrylate, dicyandiamide-diethylenetriamine copolymer, diallyldimethylamine / hydrochloride-acrylamide copolymer, dicyandiamide-formaldehyde copolymer, or a combination thereof.

[0298] A third aspect of the present invention provides a method for manufacturing a semiconductor device, which includes the step of polishing using the chemical mechanical polishing slurry composition.

[0299] Detailed explanations of the parts that overlap with the first and second aspects of this application will be omitted, but the content explained for the first and second aspects of this application can be similarly applied to the third aspect even if that explanation is omitted.

[0300] The following describes in detail the method for manufacturing a semiconductor device relating to the third aspect of this application.

[0301] First, to explain the shallow trench isolation (STI) routine process, among the processes for planarizing the insulating film, photo-etching, etching, and polishing can be classified as basic processes that are commonly applied.

[0302] The process can begin with a photoprocessing step, which is the first step in separating the elements. The photoprocessing is carried out using an auxiliary device called a track and an exposure machine that exposes the wafer to light and transfer the circuit pattern (mask) onto it. First, a photoresist is applied, but because the photoresist has high viscosity, it is applied thinly to the insulating film while the wafer is rotating. The applied photoresist needs to be at a uniform height so that the depth of the photoresist is appropriate. If the depth of the photoresist is not sufficient during exposure, photoresist residue will remain during development, and the underlying film (insulating layer) will not be sufficiently removed in the subsequent etching process. After exposure, the wafer is returned to the track device and a development process is performed to remove the photosensitive areas.

[0303] The second step is etching of the STI, which removes the insulating layer (oxide layer + nitride layer) directly beneath the developed area (the area where the photoresist film has been removed), as well as a portion of the substrate. This etching process can be dry or wet. Dry etching is typically a method that uses a plasma state to excavate. Compared to wet (liquid) etching, dry etching can be advantageous in shaping the trench by excavating downwards without etching the side walls (anisotropic etching). In this case, over-etching may occur, so it will be necessary to accurately calculate the etching endpoint before proceeding. After etching, residue remains, which can be processed.

[0304] After the trench shape is etched, the photosensitive layer is no longer useful and can be removed by ashing. In the ashing process, plasma can preferably be used to enable high-precision ashing. The shape of the semiconductor device up to the ashing process is shown in Figure 2.

[0305] A method for manufacturing a semiconductor device according to one embodiment of the present invention may include the step of simultaneously polishing a silicon oxide film, a silicon nitride film, and a polysilicon film using the chemical mechanical polishing slurry composition.

[0306] Figures 2 to 6 are cross-sectional views showing a method for manufacturing a semiconductor device according to one embodiment of the present invention.

[0307] Referring to Figure 2, a trench 13 can be formed within the upper film 11 on the lower film 10. For example, the upper film 11 can be formed on the lower film 10, and a nitride film (polishing stop film) 12 can be formed on the upper film 11. The lower film 10 may contain a film of any material. 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 contain an insulating film (oxide film), a conductive film, a semiconductor film, or a combination thereof.

[0308] If the upper film 11 includes multiple stacked insulating films, these insulating films may be of the same type or different types. For example, the upper film 11 may include alternatingly stacked silicon oxide films and silicon nitride films. The upper film 11 may further include a semiconductor film and a lower insulating film beneath the silicon oxide and silicon nitride films. For example, the lower insulating film may be located beneath the semiconductor film.

[0309] The nitride film (polishing stop film) 12 may be formed to have 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 and reaches the lower film 10. For example, the trench 13 may have a depth sufficient to expose the lower film 10.

[0310] Referring to Figure 3, STI can form a double oxide film. First, before fully embedding the insulating material in the trench 13 with space secured, a thin liner oxide film is applied as the first insulating film 14 by diffusion. This is to ensure that the second insulating film, which is deposited using CVD in a later step, is well formed on the silicon substrate. In another embodiment of the present invention, when the trench 13 is filled with high-density plasma CVD (HDPCVD), it can also serve to prevent damage from the plasma containing high energy. In another embodiment of the present invention, the first insulating film (liner oxide film) can be formed as a thin film such as a gate oxide film by injecting oxygen gas into a diffusion furnace and heating it to a high temperature. In yet another embodiment of the present invention, a nitride film may be used instead of an oxide film.

[0311] Referring to Figure 4, a first insulating film 14 and a second insulating film 15 may be formed by depositing multiple insulators to fill the trench 13. The first insulating film 14 and the second insulating film 15 may have different densities and deposition rates. According to embodiments of the present invention, the first insulating film 14 may be formed by depositing a high-density insulator, and the second insulating film 15 may be formed by depositing a low-density insulator. For 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 to extend along the inner surface of the trench 13. For example, the first insulating film 14 may have an upward-opening U-shape or pipe-shaped form.

[0312] Because the first insulating film 14 is of high density, voids are less likely to form within it, which can eliminate or significantly reduce cracks caused by voids in subsequent heat treatment processes. The second insulating film 15 can be formed by depositing a tetraethyl orthosilicate (TEOS) oxide film to a thickness sufficient to cover the polishing stop film 12 while filling the trench 13 in which the first insulating film 14 is formed. The second insulating film 15 may be formed at a faster deposition rate than the first insulating film 14. Because the deposition rate of the second insulating film 15 is faster, the trench 13 can be filled with the second insulating film 15 relatively quickly.

[0313] In another embodiment of the present invention, although not shown, the second insulating film 15 can be partially removed in order to leave the second insulating film 15 on the trench 13. For example, the second insulating film 15 may be selectively removed through a photoprocessing and etching process to limit or open a specific region, such as the cell memory region of a semiconductor device. This may remove part or all of the second insulating film 15 on the polishing stop film 12, leaving the second insulating film 15 on the trench 13. The process of opening the specific region may be performed selectively and is not necessarily required.

[0314] Referring to Figure 5, a planarization process may be performed on the second insulating film 15. For example, the second insulating film 15 may be planarized using 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 as shown in Figure 4. In this case, the surface on the nitride film (polishing stop film) 12 is relatively flat, or even if it is not flat, its non-flatness is not great, so the chemical mechanical polishing process can be easily carried out.

[0315] Subsequently, as shown in Figure 6, an STI may be formed by removing the nitride film. The purpose of the nitride film is to protect the upper film 11 from the influence of the first insulating film 14. Since the upper film 11 is a thin and reliable gate oxide film, care must be taken when handling it. When removing the nitride film by etching (wet method), 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 having a high selectivity ratio (etching ratio) for the nitride film can be used. In another embodiment of the present invention, the nitride film can also be removed by CMP. In this case, etching of the nitride film is not required, but since this may cause physical damage to the oxide film, it is preferable to chemically treat the nitride film by etching to protect the oxide film.

[0316] In another embodiment of the present invention, the chemical mechanical polishing (CMP) step completely removes the first insulating film 14 and the second insulating film 15 on the nitride film (polishing stop film, 12) after gap filling to isolate the active region from the field region, and can be broadly divided into three steps as shown in Figure 7.

[0317] In the first step, local planarization is performed while bulk CMP of the second insulating film 15 on a platen. In the second step, the second insulating film 15, whose steps have been smoothed on the platen, is cleaned or polished (Polishing), and polishing is stopped when the nitride film (polishing stop film) 12 is exposed. At this time, the point in time when the different film materials are exposed is detected using polishing endpoint detection (EPD). In the third step, any residue of the second insulating film 15 that may remain on the nitride film (polishing stop film) 12 may be removed on the platen, and the nitride film and oxide film materials may be polished and targeted.

[0318] Figure 8 shows the structure of a chemical mechanical polishing (CMP) apparatus according to one embodiment of the present invention. A feature of this apparatus is that it consists of three platens, and as mentioned above, it may be structured in which stepwise STI CMP polishing proceeds by sequentially passing through platens 1, 2, and 3. After polishing, it moves to the cleaning section, and the process is completed after cleaning is finished.

[0319] Furthermore, in the method for manufacturing a semiconductor device according to one embodiment of the present invention, the method of simultaneously polishing a silicon oxide film, a silicon nitride film, and a polysilicon film using the chemical mechanical polishing slurry composition is not limited, and any conventional polishing method and conditions can be used, and the present invention does not particularly limit this.

[0320] A chemical mechanical polishing slurry composition according to one embodiment of the present application has high dispersion stability, and the surface of the cerium oxide particles contained in the slurry composition has high Ce 3+ Because of its ceria content, the chemical polishing mechanism that forms Si-O-Ce between silica and cerium can increase the polishing rate on silicon-containing substrates, and it can be effectively used in the CMP process to remove silicon oxide films from the surface of semiconductor devices, even under conditions of low ceria content.

[0321] A fourth aspect of the present invention provides a semiconductor device comprising a substrate and a trench filled with an insulating material on the substrate, wherein the trench is produced 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 and a solvent, and the light transmittance for light at a wavelength of 500 nm is 5550% or more in an aqueous dispersion in which the content of the cerium oxide particles is adjusted to 1.0% by weight.

[0322] While detailed explanations of aspects that overlap with the first to third aspects of this application will be omitted, the content explained for the first to third aspects of this application can be similarly applied to the fourth aspect even if that explanation is omitted.

[0323] A fifth aspect of the present invention provides a method for producing cerium oxide particles for chemical mechanical polishing, comprising the steps of: preparing a raw material precursor; and grinding or precipitating cerium oxide particles in a solution containing the raw material precursor to obtain a dispersion of cerium oxide particles for chemical mechanical polishing, characterized in that the aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight has a light transmittance of 50% or more for light with a wavelength of 500 nm.

[0324] While detailed explanations of aspects that overlap with the first to fourth aspects of this application will be omitted, the content explained for the first to fourth aspects of this application can be similarly applied to the fifth aspect even if that explanation is omitted.

[0325] One embodiment of the present invention may include a step of preparing a raw material precursor. The raw material precursor can be any precursor material capable of producing cerium oxide particles as a product.

[0326] One embodiment of the present invention may include the step of grinding or precipitating cerium oxide particles in a solution containing a raw material precursor to obtain a dispersion of cerium oxide particles for chemical and mechanical polishing. The step of grinding the cerium oxide particles in a solution containing a raw material precursor may be, for example, grinding by a milling process, and the grinding method is not limited to what is within the scope of the common technical knowledge of those skilled in the art. 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 the supernatant or filtering may be further included.

[0327] In one embodiment of the present invention, the cerium precursor may be characterized by being at least one selected from the group consisting of cerium ammonium nitrate, cerium nitrate, cerium ammonium sulfate, cerium acetate, cerium chloride, cerium hydroxide, and cerium oxide.

[0328] In one embodiment of the present application, the filtering step may be carried out using a non-limiting filtration device, more preferably a filtration device with a membrane. In the case of cerium oxide particles produced by the method according to one embodiment of the present application, it can be understood that not only is the synthesis of the cerium oxide particles itself carried out in high yield, but most of the cerium precursor material is removed by the additional filtration step.

[0329] The above description of the present invention is illustrative, and a person with ordinary skill in the art to which the invention pertains will understand that it can be easily modified into other specific forms without altering the technical concept or essential components of the invention. Therefore, it should be understood that each of the above embodiments is illustrative in all respects and not limiting. For example, each component described as a single type can be implemented in a distributed manner, and similarly, each component described as distributed can be implemented in a combined manner.

[0330] The scope of this invention is defined by the claims described below, and all modifications or alterations derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of this invention. [Industrial applicability]

[0331] In the case of cerium oxide particles according to one embodiment of the present invention, the Ce on the surface of the cerium oxide 3+ By increasing the ratio of this compound, even with small particle size, it can maintain a high oxide film removal rate even at low concentrations when included in a chemical mechanical polishing slurry.

[0332] Furthermore, according to one embodiment of the present invention, it is possible to minimize surface defects on a wafer and, unlike the conventional trade-off relationship between surface defects and oxide film removal rate, it is possible to maximize the oxide film removal rate while minimizing surface defects, thereby providing cerium oxide particles and a slurry composition for chemical mechanical polishing.

[0333] Furthermore, according to one embodiment of the present invention, it can be confirmed that the addition of a cationic polymer further increases the oxide film polishing rate and simultaneously increases the selectivity ratio of the oxide film to the polysilicon film. Considering the conventional technical common sense that the addition of a cationic polymer usually sacrifices polishing speed to secure other properties, this can be said to be a unique effect of the present invention.

[0334] The effects of the present invention are not limited to those described above, but should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention as described in the claims.

Claims

1. Cerium oxide particles for chemical and mechanical polishing, When the cerium oxide particles are contained in a chemical mechanical polishing slurry, they are monodisperse. When the color of the aqueous dispersion in which the cerium oxide particle content is adjusted to 1.0% by weight is expressed in the L*a*b* color system, the L* value is 95 or higher, and the b* value is 10 to 25 (L* represents lightness, a* represents redness, and b* represents yellowness). Cerium oxide particles for chemical and mechanical polishing, characterized in that, in an aqueous dispersion in which the content of cerium oxide particles is adjusted to 1.0% by weight, the light transmittance for light with a wavelength of 500 nm is 50% or more.

2. Cerium oxide particles for chemical and mechanical polishing, When an aqueous dispersion containing cerium oxide particles adjusted to 1.0% by weight is centrifuged for 30 minutes under a centrifugal force of 4250 G, the settling rate of the cerium oxide particles is 25% by weight or less. On the surface of the cerium oxide particles for chemical and mechanical polishing Ce ３＋ It contains 28 atomic percent or more of it, Cerium oxide particles for chemical and mechanical polishing, characterized in that, in an aqueous dispersion in which the content of cerium oxide particles is adjusted to 1.0% by weight, the light transmittance for light with a wavelength of 500 nm is 50% or more.

3. The cerium oxide particles for chemical and mechanical polishing according to claim 1 or 2, characterized in that, in an aqueous dispersion in which the content of the cerium oxide particles is adjusted to 1.0% by weight, the average light transmittance for light with a wavelength of 450 to 800 nm is 50% or more.

4. The cerium oxide particles for chemical and mechanical polishing according to claim 1 or 2, characterized in that the particle size of the secondary particles of the cerium oxide particles, as measured by a dynamic light scattering (DLS) particle size analyzer, is 1 to 30 nm.

5. The cerium oxide particles for chemical and mechanical polishing according to claim 1 or 2, characterized in that the particle size of the secondary particles of the cerium oxide particles, as measured by a dynamic light scattering (DLS) particle size analyzer, is 1 to 20 nm.

6. The cerium oxide particles for chemical and mechanical polishing according to claim 1 or 2, characterized in that the particle size of the primary particles of the cerium oxide particles is 0.5 to 11 nm when subjected to X-ray diffraction (XRD) analysis.

7. The cerium oxide particles for chemical and mechanical polishing according to claim 1, characterized in that a* is -12 to -3.

8. Cerium oxide particles according to claim 1 or 2; and A solvent-containing slurry composition for chemical and mechanical polishing.

9. The chemical mechanical polishing slurry composition according to claim 8, characterized in that the cerium oxide particles are contained in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the total slurry composition.

10. The chemical mechanical polishing slurry composition according to claim 8, characterized in that the pH of the composition is 2 to 10.

11. The chemical mechanical polishing slurry composition according to claim 8 is characterized by further comprising: 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 a combination thereof.

12. The chemical mechanical polishing slurry composition according to claim 8, characterized in that the solvent is deionized water.

13. The chemical mechanical polishing slurry composition according to claim 8, characterized in that the chemical mechanical polishing slurry composition has a silicon oxide film polishing rate of 1,000 to 5,000 Å / min.

14. A method for manufacturing a semiconductor device, comprising the step of polishing using the chemical mechanical polishing slurry composition described in claim 8.

15. Steps to prepare raw material precursors; and The steps include: grinding or precipitating cerium oxide particles in a solution containing the raw material precursor to obtain a dispersion of cerium oxide particles for chemical and mechanical polishing; A method for producing cerium oxide particles for chemical and mechanical polishing according to claim 1 or 2, characterized in that the aqueous dispersion in which the content of the cerium oxide particles is adjusted to 1.0% by weight has a light transmittance of 50% or more for light with a wavelength of 500 nm.

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