Slurry composition for chemical mechanical polishing and method for manufacturing semiconductor device

Abstract

Provided are cerium oxide particles for chemical mechanical polishing and a slurry composition for chemical mechanical polishing comprising the same. By combining the characteristic cerium oxide particles of the present invention with a cationic polymer and a nitride film polishing inhibitor, a silicon oxide film / nitride film selection ratio in an STI polishing process is maximized. The present invention provides a slurry composition for chemical mechanical polishing capable of increasing the polishing speed of an oxide film, and a method for manufacturing a semiconductor device using the same.

Description

Technical Field

[0001] The present invention relates to a slurry composition for chemical mechanical polishing containing cerium oxide particles and a method for manufacturing a semiconductor device, and more particularly, to increasing the proportion of Ce on the surface of cerium oxide obtained by a synthesis method different from that of existing cerium oxide particles, so that even though the particle size is small, it can have a high oxide film removal rate at a low content, and in combination with this, a slurry composition for chemical mechanical polishing capable of reducing the polishing rate of a nitride film by an appropriate additive component to passivate a fine pattern, and a method for manufacturing a semiconductor device using the same. 3+ Background Art

[0002] As semiconductor devices become diverse and highly integrated, more sophisticated patterning techniques are being used. Therefore, the surface structure of semiconductor devices is becoming more complex, and in order to improve the accuracy of photolithography, interlayer flatness is playing a very important role in each process. In the manufacture of semiconductor devices, the chemical mechanical polishing (CMP) process is used as such a planarization technique. For example, it is also widely used in the following processes: a process of removing an insulating film that is excessively formed for interlayer insulation; a planarization process of an insulating film for shallow trench isolation (STI) that insulates an interlayer dielectric (ILD) from a chip; and a process for forming a metal conductive film such as wiring, contact slots, via contacts, etc.

[0003] For the CMP process, the polishing rate, the flatness of the polished surface, and the degree of generation of scratches are important and are determined by CMP process conditions, the type of slurry, the type of polishing pad, etc. High-purity cerium oxide particles are used for the cerium oxide slurry. In recent years, in the manufacturing process of semiconductor devices, further refined wiring has been required, but the generation of polishing scratches during polishing is a problem that needs to be overcome.

[0004] Existing cerium oxide slurries use particles with a particle size of 30 nm to 200 nm. Even if minute polishing scratches are generated during polishing, as long as they are smaller than the existing wiring width, it is not a problem. However, nowadays, continuous highly refined wiring needs to be achieved, so it has become a problem. In response to this, attempts are being made to reduce the average particle size of cerium oxide particles. However, when the average particle size of existing particles is reduced, the mechanical action decreases, and thus, there is a problem of a decrease in the polishing rate.

[0005] Even if it is intended to control the polishing rate and polishing scratches by controlling the average particle size of cerium oxide particles, it is difficult to achieve the target level of polishing scratches while maintaining the polishing rate.

[0006] In addition, in the existing slurry compositions for chemical mechanical polishing, the cerium oxide particles do not optimize the ratio of Ce 3+ to Ge 4+ , and at the same time, the average particle size at the optimal level is not disclosed. Therefore, it is necessary to study the polishing slurry containing cerium oxide particles, and the cerium oxide particles can exhibit a high oxide film removal rate despite their small particle size by increasing the ratio of Ce 3+ on the surface of cerium oxide.

[0007] In addition, for the CMP slurry containing cerium oxide particles with optimized conditions, it is also necessary to study the additive components for improvement from the viewpoints of oxide film polishing efficiency and polishing selectivity between the oxide film and the nitride film.

[0008] As described above, the inventors of the present invention have developed cerium oxide particles with a size of less than 10 nm in which the polishing rate of the oxide film obtained by precipitation in a solution is greatly improved, and by combining the cerium oxide particles with optimized conditions with additives, a slurry composition has been developed that can greatly improve the polishing rate of the silicon oxide film while passivating and adjusting the fine pattern of the nitride film, thus completing the present invention. Summary of the Invention

[0009] Technical Problem

[0010] The present invention aims to solve the above problems, and an embodiment of the present invention provides a slurry composition for chemical mechanical polishing.

[0011] In addition, another embodiment of the present invention provides a method for manufacturing a semiconductor device.

[0012] The technical problems of the present invention are not limited to the above technical problems, and those skilled in the art can clearly understand many other technical problems not pointed out from the following description.

[0013] Technical Solution

[0014] As a technical solution for solving the above technical problems, an embodiment of the present invention provides a slurry composition for chemical mechanical polishing, which includes: cerium oxide particles; a solvent; a cationic polymer; and a nitride film polishing inhibitor. 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.

[0015] The oxide film polishing rate can increase as the content of the cationic polymer increases.

[0016] The polishing rate of the nitride film can decrease as the content of the nitride film polishing inhibitor increases.

[0017] Based on the total weight of the slurry composition for chemical mechanical polishing, the content of the nitride film polishing inhibitor can be 0.001 to 1% by weight.

[0018] Based on the total weight of the slurry composition for chemical mechanical polishing, the content of the cationic polymer can be 0.001 to 1% by weight.

[0019] The cationic polymer can be Polydiallyldimethylammonium chloride (Poly(DADMAC)), Poly diethylenetriamine-2-(dimethylamino)ethylmethacrylate (Poly(DMAEM)), Poly 2-(dimethylamino)ethyl methacrylate (Poly(DMAEM)), Polyacrylamide decamethylene diamine (Poly(Aam_DCDA)), Poly(dimethylamine)-co-epichlorohydrin, Poly(dimethylamine-co-epichlorohydrin-co-Ethylenediamine), or a combination thereof.

[0020] The nitride film polishing inhibitor can be a sulfonic acid substance, a cationic surfactant, an amphoteric surfactant, or a combination thereof.

[0021] The nitride film polishing inhibitor can be at least one sulfonic acid substance selected from polystyrene sulfonate (PSS), benzenesulfonic acid, C1-4 alkylbenzenesulfonic acid, di-C1-4 alkylbenzenesulfonic acid, C5-10 alkylsulfonic acid, or salts thereof.

[0022] Based on the total weight of the slurry composition for chemical mechanical polishing, the content of the cerium oxide particles can be 0.001 to 5% by weight.

[0023] The slurry composition for chemical mechanical polishing may further comprise a pH regulator, which may be an inorganic acid, an organic acid, an amino acid, imidazole, an alkylamine, an alkanolamine, a quaternary ammonium base, ammonia, or a combination thereof. Among them, the inorganic acid is one or more selected from sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; the organic acid is one or more selected from acetic acid, citric acid, glutaric acid, glycolic acid, formic acid, lactic acid, malic acid, carotinic acid, maleic acid, oxalic acid, phthalic acid, succinic acid, and tartaric acid; the amino acid is one or more selected from lysine, glycine, alanine, arginine, valine, leucine, isoleucine, methionine, cysteine, proline, histidine, phenylalanine, serine, tris(hydroxymethyl)methylglycine, tyrosine, aspartic acid, tryptophan, and aminobutyric acid.

[0024] The pH value of the slurry composition for chemical mechanical polishing may be 2 to 10.

[0025] The slurry composition for chemical mechanical polishing may have a silicon oxide film polishing rate.

[0026] The slurry composition for chemical mechanical polishing may have a polishing selectivity of oxide film / nitride film of 200 to 2,000.

[0027] The secondary particle size of the cerium oxide particles measured by a dynamic light scattering particle size analyzer (DLS) may be 1 to 20 nm.

[0028] The primary particle size of the cerium oxide particles measured by a transmission electron microscope (TEM) may be 0.5 to 10 nm.

[0029] According to X-ray photoelectron spectroscopy (XPS) analysis, based on 100% of the total XPS peak area representing the Ce-O binding energy on the surface of the cerium oxide particles, the sum of the XPS peak areas representing the Ce 3+ -O binding energy may be 30% or more.

[0030] The cerium oxide particles may be obtained by a step of forming a dispersion of particles by precipitation in a solution containing a raw material precursor and at an acidic pH.

[0031] In addition, another embodiment of the present invention provides a method for manufacturing a semiconductor device, which includes a step of polishing using the slurry composition for chemical mechanical polishing.

[0032] Beneficial effects

[0033] According to the embodiments of the present invention, the manufactured cerium oxide particles increase Ce on the surface of cerium oxide 3+The ratio, although having a small particle size, can have a high oxide film removal rate when included in a chemical mechanical polishing slurry at a low content. At the same time, it can be confirmed that the polishing rate of the oxide film can be further increased by adding the cationic polymer in the present invention. Meanwhile, the selectivity of the oxide film / nitride film can be increased by using a nitride film polishing inhibitor, and thus fine patterns can be passivated. In view of the common technical knowledge that the addition of a cationic polymer is usually used to ensure other properties at the expense of the polishing rate, this can be regarded as a unique effect of the present invention.

[0034] In addition, according to an embodiment of the present invention, there can be provided cerium oxide particles for chemical mechanical polishing and a chemical mechanical polishing slurry composition containing the same, which can minimize the surface defects of a wafer, and different from the correlation between surface defects and oxide film removal rate considered as a trade-off relationship in the prior art, can minimize surface defects while maximizing the oxide film removal rate.

[0035] The effects of the present invention are not limited to the above effects, and it should be understood to include all effects that can be inferred from the features of the invention described in the specification or claims of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a diagram showing the oxide film removal mechanism of an embodiment of the present invention.

[0037] Figures 2a to 2e is a cross-sectional view showing a method for manufacturing a semiconductor device according to an implementation example of the present invention, Figure 2f and Figure 2g respectively show the step process of chemical mechanical polishing and the structure of a chemical mechanical polishing (CMP) apparatus according to another implementation example of the present invention.

[0038] Figure 3 is an image obtained by visually observing a dispersion liquid in which existing cerium oxide particles are dispersed and a dispersion liquid in which cerium oxide particles according to an embodiment of the present invention are dispersed.

[0039] Figure 4 is a transmission electron microscope (TEM) image of cerium oxide particles according to an embodiment of the present invention.

[0040] Figure 5 shows scanning electron microscope (SEM) and transmission electron microscope (TEM) images of existing cerium oxide particles of a comparative example.

[0041] Figure 6 shows a TEM image of existing cerium oxide particles of a comparative example.

[0042] Figure 7These are the results of measuring cerium oxide particles of an embodiment of the present invention using a dynamic light scattering particle size analyzer (DLS). The analysis is the result of measurement using a Zetasizer Ultra from Malvem Corporation.

[0043] Figure 8 These are the X-ray diffraction (XRD) analysis results of cerium oxide particles of an embodiment of the present invention.

[0044] Figure 9 These are the XPS analysis results of cerium oxide particles of an embodiment of the present invention and existing cerium oxide particles of the 60 nm level.

[0045] Figure 10 These are the FT-IR spectral analysis results of a powder composed of cerium oxide particles made according to an implementation example of the present invention and a powder composed of conventional cerium hydroxide particles.

[0046] Figure 11 These are the FT-IR spectral analysis results of a powder composed of cerium oxide particles manufactured according to an implementation example of the present invention and a powder composed of particles formed under other conditions.

[0047] Figure 12 These are the results of the light transmittance measured by ultraviolet-visible (UV-Vis) spectrophotometry for a slurry containing cerium oxide particles of an embodiment of the present invention and slurries of Comparative Examples 1 to 4 containing existing cerium oxide particles.

[0048] Figure 13 These show the effect of adding a cationic polymer on the oxidation film polishing rate in an embodiment of the present invention.

[0049] Figure 15 and Figure 16 These are images of scanning before and after chemical mechanical polishing (CMP) of an oxide wafer using a CMP slurry composition containing cerium oxide particles of an embodiment of the present invention and a CMP slurry composition containing cerium oxide particles with a size of 60 nm, respectively. Detailed Description

[0050] Hereinafter, the present invention will be described in more detail. The present invention can be implemented in various different forms, and the present invention is not limited to the embodiments described herein. The present invention is defined by the appended claims.

[0051] In addition, the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise clearly stated, singular expressions include plural expressions. Unless there is a clear contrary statement, "including" a certain component throughout the specification of the present invention does not mean excluding other components, but means that other components can be further included.

[0052] The "monodisperse" used in the present invention means that when cerium oxide particles are dispersed in a slurry, they are inhibited from aggregating into secondary particles, thereby relatively maintaining the primary particle size. This means that the secondary particle size (D50) measured by the dynamic light scattering (DLS) method 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 of the primary particle size measured by TEM. In addition, when studying the particle size distribution, etc., inevitable impurities with relatively large sizes, etc. are not excluded.

[0053] The term "transparent" used in the present invention means that when cerium oxide particles are dispersed in a slurry, the slurry composition is observed to be transparent to the naked eye. More specifically, the average light transmittance for light in the visible light region is 50% or more, preferably 70% or more, and more preferably 80% or more. This further means that the cerium oxide particles of the present invention are inhibited from aggregating into secondary particles, thereby relatively maintaining the primary particle size.

[0054] The polishing composition can be described by its polishing rate (i.e., removal rate) and its planarization efficiency. The polishing rate refers to the rate at which material is removed from the surface of the substrate, usually expressed in units of length (thickness) per unit time (e.g., angstroms / minute). Specifically, for example, the polishing pad first contacts the "high points" of the polishing surface and removes material to form a flat surface. A process that achieves a flat surface by removing less material is more efficient compared to a process that requires removing more material to achieve flatness.

[0055] The removal rate of the silicon oxide pattern tends to limit the rate of the dielectric polishing step in the STI process. Therefore, a higher removal rate of the silicon oxide pattern is beneficial for increasing the equipment throughput. However, when the removal rate of the overcoat is too fast, the trenches will be corroded due to excessive polishing of the oxide at the exposed trenches, and device defects will increase.

[0056] Hereinafter, the present invention will be described in detail.

[0057] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0058] Production Example 1. Production of cerium oxide particles

[0059] The cerium oxide particles of an embodiment of the present invention can be chemically synthesized by a bottom-up method. In the embodiments of the present invention, the cerium oxide particles were manufactured by any one of the following cerium oxide particle manufacturing methods.

[0060] According to the manufacturing method of an embodiment of the present invention, first, about 2 to 4 kg of cerium nitrate is added to a sufficient amount of deionized water and stirred. Nitric acid is added to the precursor solution to adjust the pH value to less than 1.0. Ammonia water is added to the prepared mixture and stirred until a precipitate is produced. It is confirmed that the pH of the stirred mixture is strongly acidic (less than 2), and if left standing after stirring is completed, the product will precipitate rapidly. After removing the supernatant except for the precipitate, a specified amount of deionized water is added to generate a pale yellow cerium oxide particle dispersion. The prepared dispersion is circulated and filtered through a membrane filter to obtain a transparent yellow cerium oxide dispersion.

[0061] According to the manufacturing method of another embodiment of the present invention, first, 150 g of cerium oxide or cerium hydroxide is dispersed in 3 kg of deionized water and stirred sufficiently to prevent particle precipitation. Nitric acid is added to the mixture until the pH value reaches less than 1.0. The mixture is added to a pulverizer filled with 0.05 mm zirconia beads and pulverized in a cycle at 4,000 rpm. As the pulverization progresses, it is observed that the white opaque cerium oxide dispersion gradually turns into a yellow transparent cerium oxide dispersion. After the pulverization is completed, after allowing the prepared yellow transparent cerium oxide dispersion to precipitate, it is circulated and filtered through a membrane filter to obtain a pure yellow transparent cerium oxide dispersion.

[0062] According to the manufacturing method of another embodiment of the present invention, first, about 2 to 4 kg of ammonium cerium nitrate is added to a sufficient amount of ethanol and stirred. A basic imidazole solution is added to the precursor solution and stirred until a precipitate is formed. It is confirmed that the pH of the stirred mixture is strongly acidic (less than 2), and if left standing after stirring is completed, the product will precipitate rapidly. After removing the supernatant except for the precipitate, a specified amount of deionized water is added to generate a cerium oxide particle dispersion. The prepared dispersion is circulated and filtered through a membrane filter to obtain a transparent cerium oxide dispersion.

[0063] According to the manufacturing method of another embodiment of the present invention, first, 1.1 kg of cerium nitrate and 10 kg of deionized water are mixed in a reaction vessel to prepare a strongly acidic solution. The stirring speed of the reaction vessel is maintained at 200 rpm, and room temperature is maintained. A 1:1 mixture of 25% ammonia solution and deionized water is prepared and added to the reaction vessel until the pH value reaches 7.0. After stirring for one hour, a 1:1 mixture of 70% nitric acid and deionized water is added until the pH value reaches 1.0. After raising the temperature of the reactor to 100 °C, a reaction is carried out for four hours. During the progress of the reaction, the pale purple large particles dissociate and yellow transparent cerium oxide nanoparticles are generated. The obtained particles are circulated using a membrane filter to remove impurities, and a pure cerium oxide nanoparticle dispersion is obtained.

[0064] Production Example 2. Production of CMP slurry containing cerium oxide particles

[0065] The cerium oxide particles prepared in the above Manufacturing Example 1 were added to deionized water, and the abrasive concentration was adjusted to 0.05 wt%, and triethanolamine was added to adjust the pH value to 5.5, thereby producing a CMP slurry.

[0066] According to Figure 3 , the slurry containing the existing cerium oxide particles has a high turbidity, which can be observed with the naked eye. On the contrary, the slurry containing the cerium oxide particles of the present invention is transparent, and it can be inferred that it has a monodisperse property.

[0067] Comparative Examples 1 to 4. Production of slurry compositions containing existing cerium oxide particles

[0068] Commercially available wet-process cerium oxide particles with average particle sizes of 10 nm, 30 nm, and 60 nm respectively, and cerium oxide particles in the range of 10 - 20 nm prepared separately by the calcination method were added to deionized water, and the abrasive concentration was adjusted to 0.05 wt%. Ammonia was added as a pH adjuster to adjust the final pH value to 5.5, thereby producing a CMP slurry.

[0069] Experimental Example 1. SEM and TEM analysis of cerium oxide particles

[0070] The dispersion liquid of Manufacturing Example 1 of an embodiment of the present invention was dried at about 80 - 90 °C to prepare cerium oxide particles (primary particles) in powder form (Sample A). On the other hand, cerium oxide particles used when preparing the dispersion liquids of Comparative Example 1 to Comparative Example 4 were prepared respectively (Sample B1, B2, B3, and B4 in sequence). The above-prepared samples were respectively photographed using a TEM measuring instrument.

[0071] Figure 4 is the TEM image of the cerium oxide particles of an embodiment of the present invention.

[0072] Referring to Figure 4 , for the TEM measurement results of the cerium oxide particles prepared according to an embodiment of the invention, the average particle size is about 4 nm or less (shown as 3.9 nm, 3.4 nm, and 2.9 nm respectively in repeated measurements). It can be known that the average primary particle size of the cerium oxide particles of an embodiment of the present invention is 4 nm or less. In addition, it can be confirmed that the cerium oxide particles generally have the shape of spherical particles. Spherical cerium oxide particles with a small particle size and a relatively uniform size distribution can have a large specific surface area, and excellent dispersion stability and storage stability.

[0073] Figure 5 Show the SEM and TEM images of the existing cerium oxide particles of the comparative example.

[0074] Referring to Figure 5, commercially available cerium oxide particles currently available have particle sizes corresponding to each size class, and all of the particles separately produced by the calcination method have a primary particle size greater than 10 nm on average. It can be confirmed that compared with the average particle size measured by TEM of the cerium oxide particles of an embodiment of the present invention shown in Figure 4 which is 4 nm or less, the cerium oxide particles of the prior art and the cerium oxide particles produced by the conventional calcination method have significantly coarser particle sizes. On the contrary, it has been confirmed that the particle size (primary particles) of the cerium oxide particles of the present invention is formed small, and it can be predicted that the smaller the cerium oxide particle size, the more defects such as scratches generated on the surface of the film to be polished can be reduced.

[0075] In addition, Figure 6 shows the TEM image of commercially available cerium oxide particles as a comparative example. Referring to Figure 6 , it can be confirmed that the commercially available cerium oxide particles with a particle size of 10 nm or less include particles with edges and spherical particles, and the commercially available cerium oxide particles with a particle size of 30 nm or more are angular particles with edges. On the contrary, as described above, the cerium oxide particles of the embodiment of the present invention are generally spherical. The cerium oxide particles of the present invention have a spherical particle shape and a small particle size, so a large number of particles can be included. Therefore, the probability of surface defects generated during the polishing of the silicon oxide film can be reduced, and the global flatness can be improved.

[0076] Experimental Example 2. Dynamic Light Scattering (DLS) particle size analysis of cerium oxide particles Instrument analysis

[0077] Prepare the slurry composition of Manufacturing Example 2 of an embodiment of the present invention, and the slurry compositions of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 as samples. Analyze the prepared samples separately using a DLS device.

[0078] Figure 7 is the result of dynamic light scattering (DLS) analysis (Malvern Corporation, Zetasizer Ultra) of the cerium oxide particles of an embodiment of the present invention. In addition, Table 1 shows the D50 values of the cerium oxide particles of an embodiment of the present invention and the cerium oxide particles of multiple comparative examples obtained based on dynamic light scattering (DLS) analysis.

[0079] Table 1:

[0080] Specimen D50 value (nm) Example 1 of the present invention 5.78 Example 2 of the present invention: Addition of additives 5.98 Comparative Example 1 - Existing cerium oxide particles of 10 nm or less 33.6 Comparative Example 2 - Existing cerium oxide particles of 30 nm 93.9 Comparative Example 3 - Existing cerium oxide particles of 60 nm 138.7 Comparative Example 4 - Cerium oxide particles produced by the calcination method 139.1

[0081] Referring to Figure 7 and Table 1, it is measured that the cerium oxide particles of the embodiment of the present invention have a secondary particle size D50 value of about 5.78 nm, which is 10 nm or less. Relative to the primary particle size measured by TEM in Experimental Example 1 (refer to Figure 4), about 148% to 199%, and it can be confirmed that almost no aggregation occurs in the slurry and it is monodispersed, and the particle size hardly changes.

[0082] On the contrary, the D50 particle size of cerium oxide particles in the prior art measured by dynamic light scattering (DLS) is greater than 30 nm, and the D50 value of the secondary particle size of 10-nm-level cerium oxide particles measured by dynamic light scattering (DLS) is about 336% relative to the primary particle size measured by TEM. The cerium oxide particles in the prior art have significantly larger secondary particle sizes, and thus it can be confirmed that a large amount of aggregation has occurred.

[0083] In particular, it can be confirmed that, as predicted by the inventors of the present invention, the secondary particle size of cerium oxide particles below 10 nm prepared by the supercritical hydrothermal synthesis method or the wet method under alkaline conditions is significantly larger than the primary particle size.

[0084] In addition, it was confirmed that even when a nitride film polishing inhibitor and a cationic polymer (Example 2) were contained as additives, the monodispersity of cerium oxide particles in the slurry could be maintained. Therefore, it was confirmed that the cationic polymer and the nitride film polishing inhibitor in the present invention are suitable for use in combination with the cerium oxide particles of one embodiment of the present invention.

[0085] Therefore, compared with the cerium oxide particles in the prior art of a comparative example, the cerium oxide particles of one embodiment of the present invention have lower aggregability in the slurry and can be dispersed in the slurry in a more monodispersed form.

[0086] Experimental Example 3. X-ray Diffraction (XRD) analysis of cerium oxide particles

[0087] The dispersion liquid of Production Example 1 of one embodiment of the present invention was dried at about 80 to 90 °C to prepare cerium oxide particles (primary particles) in powder form (Sample A). The Sample A was analyzed using an XRD device (Rigaku, Ultima IV). At this time, the XRD was set to Cu Kα under the conditions of 40 kV and 40 mA.

[0088] Figure 8 is the X-ray diffraction (XRD) analysis result of the cerium oxide particles of one embodiment of the present invention.

[0089] The Sample A was subjected to XRD analysis, and as a result, an XRD spectrum in the form as Figure 8 shown (X-axis: 2-degree, Y-axis: intensity) was obtained. The crystallite size calculated based on the spectrum was 3.25 nm. This is similar to the TEM analysis result of Experimental Example 1, and thus it can be confirmed that the particles of the present invention have single crystal characteristics.

[0090] Experimental Example 4. XPS analysis of cerium oxide particles

[0091] Figure 9 XPS analysis results of cerium oxide particles of an embodiment of the present invention and existing cerium oxide particles of 60 nm level. X-ray photoelectron spectroscopy (XPS) can measure the peaks of Ce-O binding energy of Ce appearing at 900.2 - 902.2 eV, 896.4 - 898.4 eV, 885.3 - 887.3 eV, and 880.1 - 882.1 eV when irradiated with soft X-ray, and analyze the atomic percentage (atomic%) through XPS fitting, so as to measure the content of Ce 3+ and Ge 3+ in cerium oxide particles. Table 2 shows the XPS result data of the cerium oxide particles of the embodiment of the present invention. 4+

[0092] Table 2:

[0093]

[0094] Based on the above XPS analysis results, it can be known that according to the calculation result of the Ce 3+ content based on the above chemical formula, the Ce 3+ content is 30% or more. It can be seen that in cerium oxide particles, Ce 3+ is the reactive sites, so the grinding amount can be increased. In the above manner, the comparison data with existing cerium oxide particles are shown in Table 3 together.

[0095] Table 3:

[0096]

[0097] As shown in Table 3, the content of Ce 3+ in the cerium oxide particles of an embodiment of the present invention is about 36.9 atomic percentage (atomic%), and it can be known from Table 1 that compared with the Ce 3+ content of less than 14 atomic percentage (atomic%) in existing 60 nm level cerium oxide particles and about 16.8% of 10 nm level cerium oxide particles prepared by hydrothermal synthesis method under supercritical or subcritical conditions recorded in existing literature, it has a higher Ce 3+ content. When having a high level of surface Ce 3+ content as in the embodiment of the present invention, the grinding rate for silicon-containing substrates can be increased through the chemical grinding mechanism of forming Si-O-Ce between silica and cerium. ​

[0098] Experimental Example 5. Confirmation of the formation of cerium oxide particles by Fourier Transform Infrared (FT-IR) spectroscopy analysis

[0099] Figure 10 It is the FT-IR spectroscopic analysis results of the powder composed of cerium oxide particles made according to an implementation example of the present invention and the powder composed of conventional cerium hydroxide particles. After drying the dispersion liquid of Manufacturing Example 1 of an embodiment of the present invention at about 80 to 90 °C to prepare cerium oxide particles (primary particles) in powder form, the spectrum was obtained using an FT-IR spectrometer. In the analysis range of 600 to 4100 cm -1 The curve was plotted by scanning more than once within the range (in the FT-IR spectrum, the wavenumber (cm -1 ) can have an error range of ±10 cm -1 ).

[0100] According to Figure 10 the analysis results of the FT-IR spectrum, the powder composed of cerium oxide particles of an embodiment of the present invention has an infrared transmittance of about 92% to 93% in the range of 3000 cm -1 to 3600 cm -1 , and an infrared transmittance of about 93% to 95% in the range of 720 cm -1 to 770 cm -1 . In the FT-IR spectrum of the powder composed of conventional cerium hydroxide particles, the infrared transmittance in the range of 3000 cm -1 to 3600 cm -1 is 75% to 90%, and the infrared transmittance in the range of 720 cm -1 to 770 cm -1 is 97% to 99%. Comparing the two, it can be confirmed that the hydroxyl (O-H group) band of cerium hydroxide particles shown by the cerium oxide particles made according to an embodiment of the present invention in the range of 3000 cm -1 to 3600 cm -1 is weaker than that of conventional cerium hydroxide particles, and a peak based on Ce-O stretching is formed in the range of 720 cm -1 to 770 cm -1 . Therefore, this result can indicate that the cerium compound made according to an embodiment of the present invention is cerium oxide.

[0101] As a comparative example, among the cerium oxide particles synthesized by the wet method similarly to an implementation example of the present invention, when synthesized under alkaline conditions, as described above, cerium hydroxide is first formed and then converted into cerium oxide through a post-process. According to as Figure 11The results of this experiment show that when FT-IR is measured immediately after the synthesis of particles synthesized under alkaline pH conditions, peaks in the range of 3000 cm -1 to 3600 cm -1 and in the range of 720 cm -1 to 770 cm -1 indicating cerium hydroxide still appear, and multiple main peaks of cerium hydroxide in Figure 10 also appear, making it difficult to consider it as containing only cerium oxide.

[0102] Experimental Example 6. Measurement of the light transmittance of the slurry containing cerium oxide particles

[0103] 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 1% by weight. On the other hand, slurry compositions (Samples B1, B2, B3, and B4, respectively) were prepared in the same manner as in Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, except that the weight ratio of cerium oxide particles in the CMP slurry was 1% by weight. The transmittance of each sample for light in the range of 200 to 1100 nm was measured using a UV-Vis spectrophotometer (JASCO).

[0104] Figure 11 Figure is the result of the transmittance measured by ultraviolet-visible (UV-Vis) spectrophotometry for the slurry containing cerium oxide particles of an embodiment of the present invention and the slurries containing existing cerium oxide particles of Comparative Example 1 to Comparative Example 4.

[0105] Cerium oxide particles of an embodiment of the present invention and multiple comparative examples were added to deionized water, and the abrasive concentration was adjusted to 1.0% by weight to prepare a CMP slurry, and the transmittance was analyzed. At this time, the spectrum in the range of 200 to 1,100 nm was measured using a UV-vis spectrophotometer (JascoUV-vis spectrophotometer).

[0106] Through the above UV-Vis analysis spectrum, the transmittance (%) of Samples A, A2, and Samples B1 to B4 at wavelengths of 500 nm, 600 nm, and 700 nm, respectively, was organized and shown in Table 4.

[0107] Table 4:

[0108]

[0109] According to Figure 11As shown in Table 2, it can be confirmed that the slurry containing the cerium oxide particles of the present invention has an average light transmittance of 50% or more for light with a wavelength of 450 to 800 nm. In addition, it can be confirmed that the light transmittance for light with a wavelength of about 500 nm is 90% or more, and the light transmittance for light with wavelengths of about 600 nm and 700 nm is 95% or more.

[0110] Conversely, the light transmittances of the slurries containing cerium oxide particles in the prior art of Comparative Examples 1 to 4 (cerium oxide particles in the prior art of 10 nm level, 30 nm level, 60 nm level, and cerium oxide particles based on the calcination method) were measured. The light transmittance of Comparative Example 4 (calcined cerium oxide particles) was almost 0%, and the average light transmittance of the slurry of Comparative Example 1 containing commercially available existing cerium oxide particles of 10 nm level was less than 80%, and the light transmittance at a wavelength of 500 nm was less than 50%. The primary particle sizes of Comparative Examples 2 and 3 were 30 nm and 60 nm respectively, which were relatively large, and the secondary particle sizes were also larger than those of the examples of the present invention (i.e., the cohesiveness in the slurry was strong). Therefore, the light transmittance in the visible light region was less than 20%.

[0111] Conversely, the light transmittance of the cerium oxide particles of an embodiment of the present invention in the visible light region is 90% or more, which means that the primary particles of the cerium oxide particles of the present invention are themselves of a small size and less aggregate into secondary particles compared with the cerium oxide particles in the prior art. Generally, when the secondary particles are larger than 20 nm, the slurry composition can be observed to be opaque with the naked eye, and the light transmittance for wavelengths in the visible light region is less than 80%.

[0112] According to the slurry composition of the present invention, when the primary particle size of the cerium oxide particles is small and the cohesiveness to form secondary particles is weak, the dispersion stability is high. Therefore, the particles can be evenly distributed, and the number of particles in contact with the wafer increases. Therefore, the oxidation film grinding speed is excellent, and the particles themselves are small. Therefore, when using the slurry composition containing the particles to grind the film to be ground, it is possible to easily predict the probability of reducing defects such as scratches on the surface.

[0113] In addition, it can be confirmed that even when a cationic polymer and a nitride film grinding inhibitor are contained as additives, the light transmittance characteristics of the present invention remain at the same level. However, when the wrong additives are selected, the monodispersibility of the cerium oxide particles of an embodiment of the present invention in the slurry may be impaired. In view of this, the cationic polymer and the nitride film grinding inhibitor selected in the present invention can meet the required characteristics without impairing the basic characteristics of the particles in the slurry.

[0114] Experimental Example 7. Comparison of the oxidation film polishing rate of cerium oxide particles

[0115] Prepare the slurry compositions of Production Example 2 and Production Example 3 of an embodiment of the present invention and the slurry compositions of a plurality of Comparative Examples as samples, respectively.

[0116] The polishing of the oxide film wafer using the above samples was carried out using a polishing machine ( LK CMP, Applied Materials). Specifically, a PE-TEOS silicon oxide film wafer (300 mm PE-TEOS Wafer) was mounted on a polishing pad (Platen), and the surface of the wafer was brought into contact with the pad (ICl010, DOW) of the polishing machine. Next, the slurry composition used as a sample was supplied at a rate of 200 mL / min, and the polishing pad (Platen) and the pad of the polishing machine were rotated to perform a polishing process. At this time, the rotation speed of the polishing pad and the rotation speed of the head were 67 rpm / 65 rpm, the polishing pressure was 2 psi, and the polishing time was 60 seconds. On the other hand, the thickness of the silicon oxide film of the wafer was measured using ST5000 (Spectra Thick 5000ST, K-MAC). The results are shown in Table 5.

[0117] Table 5:

[0118]

[0119] As shown in Table 5, when the slurry composition of the embodiment was used, the removal rate of the silicon oxide film was about 6 times or more that of the slurry compositions of the plurality of Comparative Examples. This is because the particle size of the cerium oxide particles contained in the slurry composition of the embodiment is small. Therefore, the number of particles effectively used for polishing is large relative to the content, and the content (molar ratio and / or weight ratio) of Ce on the surface is high. Therefore, the chemical reactivity with the surface of the silicon oxide film is improved. 3+ The content (molar ratio and / or weight ratio) of is high, so the chemical reactivity with the surface of the silicon oxide film is improved.

[0120] In addition, it can be confirmed that, compared with the slurry composition without multiple additive substances in Production Example 2, the slurry composition in Production Example 3 further containing a cationic polymer and a nitride film polishing inhibitor further improves the polishing rate of the oxide film. From this, it can be known that when the cationic polymer of an embodiment of the present invention is combined with the cerium oxide particles of an embodiment of the present invention, the cationic polymer is disposed between the multiple cerium oxide particles of an embodiment of the present invention, and the unique monodispersity can be further improved, so that the number and area of the particles in contact with the silicon oxide film are maximized. Therefore, it can be considered that within a predetermined content range, the polishing rate of the oxide film will be increased. When exceeding the predetermined range, the recess regulator itself may block or hinder the contact between the cerium oxide particles and a part of the oxide film, so the polishing rate of the oxide film will be reduced. This operation of the polishing rate of the oxide film based on the content of the cationic polymer is characteristic. When using ordinary cerium oxide particles and a cationic polymer such as that described in the present invention together, it is completely opposite to observing a decrease in the polishing rate of the oxide film from the initial content. This characteristic is briefly shown in Figure 13 in.

[0121] When adding the cationic polymer of an embodiment of the present invention to a slurry composition containing ordinary cerium oxide particles with a size of 10 nm or less manufactured according to the prior art, on the contrary, the polishing rate of the oxide film will be reduced. Therefore, this characteristic should be further concerned.

[0122] Experimental Example 8. Defect evaluation of cerium oxide particles

[0123] Figure 15 and Figure 16 are images obtained by scanning the oxide wafer before and after CMP using a CMP slurry composition containing cerium oxide particles of an embodiment of the present invention and a CMP slurry composition containing cerium oxide particles with a size of 60 nm, respectively.

[0124] The surface analysis of the oxide wafer is performed in a full wafer scan mode using an AIT-XP device.

[0125] Refer to Figure 15 and Figure 16, after performing CMP on the surface of an oxide wafer using a CMP slurry composition containing the cerium oxide particles of the embodiments of the present invention, and analyzing the surface of the oxide wafer before and after CMP, the number of defects before CMP was 6, and the number of defects after CMP was 1. Therefore, after performing CMP using the embodiments of the present invention, the defects on the surface of the oxide wafer are reduced. Additionally, in the CMP process, no scratches are generated on the surface of the wafer. Conversely, after performing CMP on the surface of an oxide wafer using a CMP slurry composition containing cerium oxide particles in the prior art, and analyzing the surface of the oxide wafer before and after CMP, the number of defects before CMP was 34, and the number of defects after CMP increased to 64. It can be seen that the cerium oxide particles in the prior art left scratches on the surface of the wafer. This indicates that since the particle size of the cerium oxide particles of an embodiment of the present invention is smaller than that of the cerium oxide particles in the prior art, the probability of generating defects on the surface of the oxide wafer to be polished can be significantly reduced. Additionally, it can be fully speculated that the cerium oxide particles of an embodiment of the present invention are monodispersed in the slurry and are themselves tiny particles. Therefore, even if additives are included, the defects can be minimized.

[0126] Experimental Example 9. Analysis of the polishing selectivity ratio of the oxide film / nitride film depending on the addition of additives

[0127] After adding the cerium oxide particles manufactured according to an embodiment of the present invention and commercially available 60 nm - grade cerium oxide particles to deionized water and adjusting the pH value to 5.8, a cationic polymer was added as recorded in Table 6, and the polishing rate of the oxide film was measured under the same polishing conditions as in Experimental Example 7. and the polishing rate of the nitride film

[0128] Table 6:

[0129]

[0130] Referring to Table 6, it can be confirmed that when a cationic polymer and a nitride film passivation regulator of an embodiment of the present invention are included, the polishing rate of the nitride film in the STI process is significantly reduced (30% - 80%) compared to when no additives are present. This is an effect obtained without compromising the characteristics of the particles of an embodiment of the present invention in the slurry, and thus, it is worthy of attention. As Figure 14 shown, the adsorption amount of the cationic polymer of an embodiment of the present invention on the silicon oxide film (TEOS) is higher than that on the nitride film. Therefore, when used in an appropriate amount, while increasing the polishing rate of TEOS, the polishing rate of the nitride film is reduced. Additionally, it is known that when the cationic polymer of an embodiment of the present invention is added, it has the characteristic of reducing the polishing rate of the nitride film.

[0131] Embodiment

[0132] A first embodiment of the present invention provides a slurry composition for chemical mechanical polishing, which comprises: cerium oxide particles; a solvent; a cationic polymer; and a nitride film polishing inhibitor. 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 having a wavelength of 450 to 800 nm is 50% or more.

[0133] Hereinafter, the slurry composition for chemical mechanical polishing according to the first embodiment of the present invention will be described in detail.

[0134] Figure 1 is a diagram showing an oxide film removal mechanism of an embodiment of the present invention. As Figure 1 shown, only the Ce 3+ ions on the surface of the cerium oxide particles can be activated to react smoothly with SiO 2

[0135] In one implementation example of the present invention, by including the cationic polymer and the nitride film polishing inhibitor, the nitride film polishing rate can be significantly reduced. This is the main technical feature that differentiates the slurry composition for chemical mechanical polishing of the present invention from the prior art. Therefore, it will be described in detail below. In particular, this feature is combined with the unique cerium oxide particles of the present invention, thereby exhibiting a unique effect. Therefore, it will be described in detail below.

[0136] In one implementation example of the present invention, the cationic polymer can play several roles in the slurry composition for chemical mechanical polishing of the present invention. First, it can reduce the dents and corrosion that may occur in the STI process. Second, it can act as a stabilizer for the slurry composition and can act as a pH buffer to ensure particle dispersibility and dispersion stability. In addition, the cationic polymer of the present invention can also act as a polishing accelerator for the oxide film. In existing polishing slurries, a cationic polymer is added to improve dispersion stability or to protect the field oxide when removing steps, and in order to obtain such characteristics, a part of the oxide film polishing rate has to be sacrificed. On the contrary, the cationic polymer added to the polishing slurry of the present invention can not only improve dispersion stability, but also improve the overall polishing rate for the oxide film as the amount of the cationic polymer added increases.

[0137] As described below, the cerium oxide particles in one implementation example of the present invention are obtained by a wet method at an acidic pH, and are obtained in the form of a dispersion. Even if a solvent is directly added thereto to prepare a slurry, ultrafine cerium oxide nanoparticles can have a monodispersed form without an additional redispersion process, and the Ce 3+ ​The content also remains at a relatively high level, and it is a particle that has a high level of oxide film polishing rate when manufacturing a slurry composition for chemical mechanical polishing. As described above, the inventors of the present invention confirmed through research that even if various additives used in the prior art are added to the cerium oxide particles of an embodiment of the present invention with inherent characteristics, it is difficult to exhibit the performance desired in the prior art. In addition, from the perspective of those skilled in the art using nanoparticles, a composition containing nanoparticles also needs to find and combine suitable multiple substances for specific nanoparticles to achieve the required characteristics or performance. A slurry composition of an embodiment of the present invention can further add a nitride film polishing inhibitor to minimize the polishing rate of the nitride film while not impairing (but rather improving) the excellent oxide film polishing rate performance of the cerium oxide particles.

[0138] In one embodiment of the present invention, the principles by which the unique cerium oxide particles, the cationic polymer, and the nitride film polishing inhibitor substance of the present invention take effect are as follows. The cerium oxide particles of one embodiment of the present invention have the characteristic of being monodispersed in the slurry without an additional dispersion process. The cationic polymer is located between the monodispersed cerium oxide particles to enable multiple cerium oxide particles to uniformly and smoothly contact the silicon oxide film, thereby maximizing the polishing rate. In addition, the nitride film polishing inhibitor can play a role in preventing the cerium oxide particles from contacting the nitride film, thereby minimizing the polishing rate of the nitride film. When used in an appropriate amount, it will not prevent the polishing rate of the silicon oxide film.

[0139] In one embodiment of the present invention, based on the total weight of the slurry composition for chemical mechanical polishing, the content of the cationic polymer may be 0.001 wt% or more, 0.002 wt% or more, 0.003 wt% or more, 0.004 wt% or more, or 0.005 wt% or more, and may be 1 wt% or less, 0.5 wt% or less, 0.1 wt% or less, 0.05 wt% or less, 0.03 wt% or less, 0.01 wt% or less. When the content of the cationic polymer is less than 0.001 wt% based on the total weight of the slurry composition for chemical mechanical polishing, the content is too small to fully act as an oxide film polishing promoter, and thus cannot affect the polishing rate of the oxide film. On the contrary, when it is greater than 1 wt%, the added cationic polymer will hinder the polishing process of cerium oxide, instead reducing the polishing rate of the oxide film or becoming an impurity in the slurry composition.

[0140] In an implementation example of the present invention, based on the total weight of the slurry composition for chemical mechanical polishing, the content of the nitride film polishing inhibitor may be 0.001 wt% or more, 0.002 wt% or more, 0.003 wt% or more, 0.004 wt% or more, or 0.005 wt% or more, and may be 1 wt% or less, 0.5 wt% or less, 0.1 wt% or less, 0.05 wt% or less, 0.03 wt% or less, 0.01 wt% or less. When the content of the nitride film polishing inhibitor is less than 0.001 wt% based on the total weight of the slurry composition for chemical mechanical polishing, the content is too small to fully play the role of the nitride film polishing inhibitor, so it cannot affect the reduction of the polishing rate of the nitride film. When it is greater than 1 wt%, the added nitride film polishing inhibitor will hinder the polishing process of cerium oxide, instead reducing the polishing rate of the oxide film or becoming impurities in the slurry composition.

[0141] In an implementation example of the present invention, the cationic polymer may be a polymer or copolymer containing an amine group or an amino group. For example, the cationic polymer may be polydiallyldimethylammonium chloride, poly(diethylenetriamine-2-(dimethylamino)ethyl methacrylate), poly(2-(dimethylamino)ethyl methacrylate), polyacrylamide decamethylenediamine, dimethylamine-epichlorohydrin copolymer, poly(dimethylamine-co-epichlorohydrin-co-ethylenediamine), or a combination thereof.

[0142] In an implementation example of the present invention, the nitride film polishing inhibitor may be at least one sulfonic acid substance selected from polystyrene sulfonic acid (PSS), benzenesulfonic acid, C1-4 alkylbenzenesulfonic acid, di-C1-4 alkylbenzenesulfonic acid, C5-10 alkylsulfonic acid, or their salts.

[0143] Hereinafter, cerium oxide particles in an implementation example of the present invention will be described. In an implementation example of the present invention, the slurry composition for chemical mechanical polishing uses cerium oxide particles with excellent dispersion stability, especially excellent polishing rate for silicon oxide films.

[0144] In an implementation example of the present invention, the Zeta potential value of the cerium oxide particles included in the slurry as polishing particles may be positive. Preferably, in the range of pH value from 2 to 8, the Zeta potential value may be 1 to 80 mV, 5 to 60 mV, or 10 to 50 mV. The Zeta potential value of the cerium oxide particles is positive, so that the polarity of the surface of the silicon oxide film is negative. Therefore, the polishing efficiency is improved due to the attraction between the cerium oxide particles and the surface of the silicon oxide film.

[0145] In an implementation example of the present invention, the hardness of the cerium oxide particles is lower than that of the silica particles or alumina particles. However, based on the chemical polishing mechanism of forming Si-O-Ce bonds between silica and cerium, the polishing rate for surfaces containing silicon such as glass or semiconductor substrates is very fast. Therefore, it is beneficial for the polishing of semiconductor substrates.

[0146] In an implementation example of the present invention, dynamic light scattering (DLS) analysis can be used to measure the particle size (secondary particles) of the cerium oxide particles in the slurry. The dynamic light scattering analysis can be measured by analysis equipment well-known to those skilled in the art. Preferably, it is measured using a particle size analyzer of Anton Parr company or ZetasizerUltra of Malvern company, but this is only an example and is not limited thereto. The above-mentioned secondary particles are formed by the aggregation of the following primary particles in the slurry. It can be seen that the larger the surface area of the particles, the larger the range of the gravitational action, and thus it is easy to aggregate. In addition, when the pH range in the solution passes through the isoelectric point where the Zeta potential of the particles is 0, secondary particles will be aggregated. As disclosed in many prior arts, the isoelectric point pH value of cerium oxide particles is about 7. When the particles are synthesized under alkaline conditions in a wet process, it is necessary to adjust the pH and pass through the isoelectric point in order to manufacture the slurry, and it is difficult to have monodispersity in the slurry like the particles in an implementation example of the present invention.

[0147] In an implementation example of the present invention, the particle size of the cerium oxide particles measured by a dynamic light scattering particle size analyzer (DLS) can be 1 to 30 nm. In another implementation example of the present invention, it can 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 can 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. When the secondary particle size is greater than the above range, it means that a large amount of primary particles are aggregated in the slurry composition, and it is difficult to regard it as a monodisperse slurry at this time. When the secondary particle size is less than the above range, the polishing rate for the target film will be excessively hindered, resulting in a reduction in polishing efficiency.

[0148] In an implementation example of the present invention, the particle size (primary particle) of the cerium oxide particles can be measured using a transmission electron microscope (TEM). In an implementation example of the present invention, the particle size of the cerium oxide particles measured using the transmission electron microscope can be 11 nm or less. In another implementation example, it can be 10.8 nm or less, 10.5 nm or less, 10.2 nm or less, 10 nm or less, 9.5 nm or less, 9.0 nm or less, 8.5 nm or less, 8.0 nm or less, 7.5 nm or less, 7.0 nm or less, 6.5 nm or less, 6.0 nm or less, 5.5 nm or less, 5.0 nm or less, 4.5 nm or less, or 4.0 nm or less, and can be 0.3 nm or more, 0.5 nm or more, 0.7 nm or more, 1.0 nm or more, 1.1 nm or more, 1.2 nm or more, 1.3 nm or more, 1.4 nm or more, 1.5 nm or more, 1.6 nm or more, 1.7 nm or more, 1.8 nm or more, 1.9 nm or more, 2.0 nm or more, 2.1 nm or more, 2.2 nm or more, 2.3 nm or more, or 2.4 nm or more. When the particle size of the cerium oxide particles is less than 0.3 nm, the crystallinity decreases, and the polishing rate for the target film decreases excessively, resulting in a decrease in polishing efficiency. On the contrary, when it is greater than 11 nm, there is a risk of generating a large number of surface defects such as scratches. In addition, in an implementation example of the present invention, the average particle size of the cerium oxide particles measured using the transmission electron microscope can be 0.5 to 10 nm, preferably 1 to 10 nm, and more preferably 2 to 9 nm.

[0149] To describe the cerium oxide particles in an implementation example of the present invention, when the particle size of the cerium oxide particles measured using a dynamic light scattering (DLS) particle size analyzer is set as a, and the particle size of the cerium oxide particles measured using a transmission electron microscope (TEM) is set as b, the cerium oxide particles can satisfy the following formula 1.

[0150] Formula 1:

[0151] a ≤ 2.2b

[0152] This characteristic can be used as an index indicating that the cerium oxide particles of the present invention have low cohesiveness when dispersed in a slurry. When the coefficient of b is greater than 2.2, it indicates that a large amount of aggregation has occurred in the slurry, which means that it is difficult to suppress wafer surface defects during polishing due to the coarsening of the particle size.

[0153] In an implementation example of the present invention, the particle size (primary particles) of the cerium oxide particles can be measured by X-ray diffraction (XRD) analysis. In an implementation example of the present invention, the particle size of the cerium oxide particles measured by X-ray diffraction analysis can be 11 nm or less. In another implementation example, it can be 10.8 nm or less, 10.5 nm or less, 10.2 nm or less, 10 nm or less, 9.5 nm or less, 9.0 nm or less, 8.5 nm or less, 8.0 nm or less, 7.5 nm or less, 7.0 nm or less, 6.5 nm or less, 6.0 nm or less, 5.5 nm or less, 5.0 nm or less, 4.5 nm or less, or 4.0 nm or less, and can be 0.3 nm or more, 0.5 nm or more, 0.7 nm or more, 1.0 nm or more, 1.1 nm or more, 1.2 nm or more, 1.3 nm or more, 1.4 nm or more, 1.5 nm or more, 1.6 nm or more, 1.7 nm or more, 1.8 nm or more, 1.9 nm or more, 2.0 nm or more, 2.1 nm or more, 2.2 nm or more, 2.3 nm or more, or 2.4 nm or more. When the particle size of the cerium oxide particles is less than 0.3 nm, the crystallinity decreases, and the polishing rate of the target film decreases excessively, resulting in a decrease in polishing efficiency. On the contrary, when it is greater than 11 nm, there is a risk of generating a large number of surface defects such as scratches. In addition, in an implementation example of the present invention, the average particle size of the cerium oxide particles measured by the X-ray diffraction (XRD) analysis can be 0.5 to 10 nm, preferably 1 to 10 nm, and more preferably 2 to 9 nm.

[0154] In an implementation example of the present invention, XPS can be used to analyze the Ce content on the surface of the cerium oxide particles. For example, the thetaprobe base system manufactured by Thermo Fisher Scientific Co can be used. The Ce content on the surface of the cerium oxide polishing particles can be calculated based on the following Chemical Formula 1. 3+ In an implementation example of the present invention, XPS can be used to analyze the Ce content on the surface of the cerium oxide particles. For example, the thetaprobe base system manufactured by Thermo Fisher Scientific Co can be used. The Ce content on the surface of the cerium oxide polishing particles can be calculated based on the following Chemical Formula 1. 3+ content.

[0155] Chemical Formula 1:

[0156] Ce 3+ content (%) = (Ce 3+ peak area) / [(Ce 3+ peak area) + (Ce 4+ peak area)]

[0157] In an implementation example, according to the X-ray photoelectron spectroscopy (XPS) analysis on the surface of the cerium oxide particles, the Ce 3+The XPS peaks of Ce-O binding 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, according to the X-ray photoelectron spectroscopy (XPS) analysis on the surface of the cerium oxide particles, it is shown that Ce 3+ The XPS peaks of Ce-O binding energy include a first peak of 900.2-902.2 eV, a second peak of 896.4-898.4 eV, a third peak of 885.3-887.3 eV, and a fourth peak of 880.1-882.1 eV.

[0158] In one implementation example of the present invention, relative to the total area of ​​the XPS peaks, the area of ​​the first peak may be greater than 3% or greater than 4%, the areas of the second peak and the fourth peak may be greater than 5%, greater than 7% or greater than 10%, respectively, and the area of ​​the third peak may be greater than 4%, greater than 5% or greater than 6%.

[0159] In addition, in one embodiment of the present invention, according to X-ray photoelectron spectroscopy (XPS) analysis, Ce 3+ The ratio of the sum of the XPS peak areas of the Ce-O binding energy of the cerium oxide particles to the sum of the XPS peak areas of the Ce-O binding energy of the cerium oxide particles on the surface may be 0.29 to 0.70. 3+ The ratio of the sum of the XPS peak areas of the Ce-O binding energy of the cerium oxide particles to the sum of the XPS peak areas of the Ce-O binding energy on the surface of the cerium oxide particles may be 0.18 or more, 0.19 or more, 0.192 or more, 0.195 or more, 0.198 or more, 0.20 or more, 0.202 or more, 0.205 or more, 0.208 or more, 0.21 or more, 0.22 or more, 0.24 or more, 0.25 or more, 0.27 or more, 0.28 or more, 0.30 or more, 0.31 or more, 0.32 or more, 0.33 or more, 0.34 or more, 0.36 or more, 0.37 or more, 0.38 or more, 0.39 or more, 0.40 or more, 0.41 or more, 0.42 or more, 0.43 or more, 0.44 or more, 0.45 or more, 0.46 or more, 0.47 or more, 0.48 or more, 0.49 or more, 0.50 or more, 0.51 or more, 0.52 or more, 0.53 or more, 0.54 or more, 0.55 or more, 0.56 or more, 0.57 or more, 0.58 or more, 0.59 or more, 0.60 or more, 0.61 or more, 0.62 or more, 0.63 or more, 0.64 or more, 0.65 or more, 0.66 or more, 0.67 or more, 0.68 or more, 0.69 or more, 0.70 or more, 0.71 or more, 0.7 32 or more or 0.35 or more, and can 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. When it is less than the above range, the surface of the cerium oxide particles cannot have sufficient Ce. 3+ Therefore, it is difficult to expect that the oxide film polishing rate is sufficiently increased. When it is larger than the above range, it is difficult to explain that it exists in the form of cerium oxide particles in consideration of the oxidation number.

[0160] That is, in an implementation example of the present invention, according to X-ray photoelectron spectroscopy (XPS) analysis, Ce on the surface of the cerium oxide particles for chemical mechanical polishing 3+ content may be 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 be 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.

[0161] The cerium oxide particles of an implementation example of the present invention have the characteristic of high Ce 3+ content on the particle surface. This is because in an implementation example of the present invention, the process of particle synthesis in the liquid phase through a wet process is carried out under acidic conditions. Generally, a cerium precursor containing trivalent cerium maintains the cerium trivalent state at acidic pH. In the manufacturing method of an implementation example of the present invention, the overall process of particle synthesis does not include conversion to basic pH. Therefore, the content of trivalent cerium on the surface of the synthesized particles is high. The characteristic of the content of trivalent cerium on the surface of such cerium oxide particles is related to whether surface defects are formed and maintained in the manufacturing process. Therefore, it is a characteristic independent of technical characteristics such as the above-mentioned primary particle or secondary particle size. As described above, the Ce 3+ content on the particle surface of the cerium oxide particles of an implementation example of the present invention is high. When the Ce 3+ content on the surface is relatively high, the polishing rate of the oxide film can be improved.

[0162] In one implementation example of the present invention, when Fourier-transform infrared (FT-IR) spectrometry is performed on the powder composed of the cerium oxide particles, in the spectrum specific to the FT-IR spectrometry, in the range of 3000 cm-1 to 3600 cm-1, the infrared transmittance of the powder composed of the cerium oxide particles can be 90% or more, or 100% or less, 97% or less, or 95% or less. Additionally, in one implementation example of the present invention, in the range of 720 cm-1 to 770 cm-1, the infrared transmittance of the powder can be 96% or less, and can be 85% or more, 88% or more, more preferably 90% or more, and even more preferably 92% or more. In the range of 3000 cm-1 to 3600 cm-1 of the FT-IR spectrum, the infrared transmittance having a value within the above range indicates that the hydroxyl (O-H group) band is relatively weak, which is different from the FT-IR spectrum of the powder composed of cerium hydroxide particles. Additionally, in the range of 720 cm-1 to 770 cm-1 of the FT-IR spectrum of the powder composed of the cerium oxide particles of one embodiment of the present invention, there is a peak indicating the infrared transmittance within the above range, which can indicate that Ce-O stretching occurs within the above range, and this can indicate that the particles manufactured according to one embodiment of the present invention exhibit the characteristics of cerium oxide particles. In particular, in the wet method of the cerium oxide particle manufacturing method, when synthesized under alkaline conditions, additional heat treatment or long-term exposure to oxygen and other processes for conversion to cerium oxide are inevitably accompanied. Therefore, when measuring FT-IR immediately after the particle synthesis process and before the subsequent process, multiple peaks related to cerium hydroxide are detected. However, the cerium oxide particles of one implementation example of the present invention do not adopt the process of first forming cerium hydroxide and then converting it to cerium oxide. Therefore, even when measuring immediately after synthesis, only multiple peaks related to cerium oxide are detected.

[0163] In one implementation example of the present invention, the cerium oxide primary particles can be one or more selected from spherical, cubic shape, tetragonal shape, orthorhombic shape, rhombohedral shape, monoclinic shape, hexagonal shape, triclinic shape, and cuboctahedron shape, and preferably spherical particles.

[0164] In one implementation example of the present invention, the cerium oxide particles can be made by a method of growing particles through chemical synthesis, preferably in a bottom-up manner. As the synthesis method of the cerium oxide particles, methods such as sol-gel method, supercritical reaction, hydrothermal reaction or co-precipitation method can be used, but are not limited thereto. The bottom-up method, as a kind of chemical synthesis that has attracted much attention in recent years, is a method of growing starting materials of atoms or molecules into nanoparticles through chemical reactions.

[0165] In one implementation example of the present invention, the polishing composition contains wet-process cerium oxide particles. The wet-process cerium oxide particles can be any suitable wet-process cerium oxide particles. For example, the wet-process cerium oxide particles can be precipitated cerium oxide particles or polycondensed cerium oxide particles including colloidal cerium oxide particles.

[0166] In one implementation example of the present invention, the wet-process cerium oxide particles preferably have defects on the surface of the particles. Although not intended to be combined with any specific theory, the crushing of cerium oxide particles will cause defects to appear on the surface of the cerium oxide particles, and such defects will affect the performance of the cerium oxide particles in the chemical mechanical polishing composition. In particular, the cerium oxide particles may break when crushed, thus exposing a relatively less favorable surface state. This process is relaxation, and atoms with limited reconstruction ability and limited ability to recover to a more favorable state around the surface of the cerium oxide particles will form defects on the particle surface.

[0167] In one implementation example of the present invention, when generating secondary particles of the polishing material, the solvents each have an inherent dielectric constant value, and in the nucleation and crystal growth during the synthesis of the powder, the dielectric constant of the solvent will change the surface energy or surface charge, etc., thereby affecting the condensation and growth of the nuclei, and this will affect the size and shape of the powder, etc. The dielectric constant of the solvent is proportional to the surface potential (Zeta potential) of the particles dispersed in the solvent. When the Zeta potential is small, the surface repulsive force between the fine particles or between the nuclei generated by the reaction is small. Therefore, it is in an unstable state, making the fine particles or nuclei condense rapidly. At this time, the magnitudes of the surface repulsive forces between the fine particles or nuclei are all similar, so they can condense with a uniform size. The secondary particles condensed in this way are formed by the primary fine particles or nuclei growing into larger-sized particles through particle coalescence processes such as stronger condensation or Ostwald ripening according to reaction conditions such as temperature and concentration.

[0168] When using the cerium oxide as a polishing material, due to the strong reactivity between cerium oxide and silicon oxide, Si-O-Ce chemical bonding occurs. Therefore, different from mechanical polishing that only removes the hydrated layer formed on the surface, cerium oxide removes silicon oxide blocks from the surface of the silicon oxide film in a peeling manner, thereby polishing the silicon oxide film. In addition, the cerium oxide powder in the embodiments of the present invention has a small particle size, so its strength is low, and the global flatness of polishing is excellent. At the same time, the problem of micro-scratches formed by large particles can also be solved.

[0169] Hereinafter, a slurry composition for chemical mechanical polishing containing the cerium oxide particles and a nitride film polishing inhibitor according to an embodiment of the present invention will be described in detail.

[0170] In one embodiment of the present invention, 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 can be 50% or more, or 60% or more. The average light transmittance is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. In addition, in another embodiment of the present invention, the light transmittance for light with a wavelength of 500 nm can be 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, or 80% or more. In addition, the light transmittance for light with a wavelength of 600 nm can be 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 can be 87% or more, 90% or more, 93% or more, or 95% or more. The light transmittance value of the slurry composition satisfying the above range means that the primary particle size of the cerium oxide particles in one embodiment of the present invention is small in itself, and compared with the cerium oxide particles in the prior art, they agglomerate into secondary particles less. When the cohesiveness is low, the dispersion stability is high, so the particles can be evenly distributed, and the number of particles in contact with the wafer increases. Therefore, the oxidation film polishing speed is excellent, and the particles themselves are tiny. Therefore, when using the slurry composition containing the particles to polish the film to be polished, the probability of defects such as scratches generated on the surface can be reduced. That is, based on the primary particles, the higher the light transmittance of the cerium oxide particles below 10 nm in the visible light region, the more excellent the silicon oxide film polishing speed. In addition, even if the cationic polymer and the nitride film polishing inhibitor are further included as additives, this light transmittance characteristic can be maintained.

[0171] In an implementation example of the present invention, based on the weight of the slurry composition for chemical mechanical polishing, the content of the cerium oxide particles may be 5% by weight or less. In another implementation example of the present invention, based on the weight of the slurry composition for chemical mechanical polishing, the content of the cerium oxide particles may be 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, and may be 0.0001% by weight or more or 0.001% by weight or more. Although the slurry composition for chemical mechanical polishing of the present invention uses slurries with the same polishing rate, even if a lower content of the cerium oxide particles is added based on the weight of the slurry composition for chemical mechanical polishing, a higher polishing efficiency of the oxide film can be achieved.

[0172] In an implementation example of the present invention, the pH value of the composition may be 2 to 10. In an implementation example of the present invention, the slurry composition for chemical mechanical polishing may include one or more acidic or basic pH regulators and buffers capable of adjusting the pH in consideration of the final pH of the composition, polishing rate, polishing selectivity ratio, etc. The pH regulator for adjusting the pH may use a pH regulator that can adjust the pH without affecting the characteristics of the slurry composition for chemical mechanical polishing. In an implementation example of the present invention, the pH regulator may be an acidic pH regulator or a basic pH regulator to achieve an appropriate pH value.

[0173] In an implementation example of the present invention, the pH regulator may be, for example, an inorganic acid, an organic acid, an amino acid, imidazole, an alkylamine, an alkanolamine, a quaternary ammonium base, ammonia, or a combination thereof. Among them, the inorganic acid is one or more selected from sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid; the organic acid is one or more selected from acetic acid, citric acid, gluconic acid, glycolic acid, formic acid, lactic acid, malic acid, fumaric acid, maleic acid, oxalic acid, phthalic acid, succinic acid, and tartaric acid; the amino acid is one or more selected from lysine, glycine, alanine, arginine, valine, leucine, isoleucine, methionine, cysteine, proline, histidine, phenylalanine, serine, tris(hydroxymethyl)methylglycine, tyrosine, aspartic acid, tryptophan, and aminobutyric acid. In particular, the pH regulator may be triethanolamine, tetramethylammonium hydroxide (TMAH or TMAOH), or tetraethylammonium hydroxide (TEAH or TEA-OH). Additionally, the pH regulator may be, for example, one or more selected from ammoniummethyl propanol (AMP), tetra methyl ammonium hydroxide (TMAH), potassium hydroxide, sodium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, sodium bicarbonate, sodium carbonate, triethanolamine, tromethamine, and nicotinamide. Preferably, the pH regulator may be triethanolamine or aminobutyric acid.

[0174] In an implementation example of the present invention, the solvent may be any solvent used in the slurry composition for chemical mechanical polishing. For example, deionized water may be used, but the present invention is not limited thereto. Additionally, ultrapure water is preferably used. The content of the solvent may be the remaining content obtained by subtracting the content of the cerium oxide particles and other additional additives from the total amount of the slurry composition for chemical mechanical polishing. In an implementation example of the present invention, the solvent includes water (e.g., deionized water) as an aqueous carrier and one or more water-miscible organic solvents. The organic solvents that can be used include: alcohols, such as allyl alcohol, isopropyl alcohol, ethanol, 1-propanol, methanol, 1-hexanol, etc.; aldehydes, such as acetaldehyde, etc.; ketones, such as acetone, diacetone alcohol, methyl ethyl ketone, etc.; esters, such as ethyl formate, propyl formate, ethyl acetate, methyl acetate, methyl lactate, butyl lactate, ethyl lactate, etc.; ethers including sulfoxides (e.g., dimethyl sulfoxide (DMSO)), tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, etc.; amides, such as N,N-dimethylformamide, dimethylimidazolinone, N-methylpyrrolidone, etc.; polyols and their derivatives, such as ethylene glycol, glycerol, diethylene glycol, diethylene glycol monomethyl ether, etc.; and nitrogen-containing organic compounds, such as acetonitrile, pentylamine, isopropylamine, dimethylamine, etc.

[0175] In one implementation example of the present invention, the polishing composition further includes one or more other additives as appropriate. The polishing composition may include rheology modifiers such as thickeners and solidifying agents (e.g., high molecular weight rheology modifiers such as polyurethane), biocides (e.g., KATHON TM LX), etc.

[0176] In one implementation example of the present invention, the slurry composition for chemical mechanical polishing has excellent dispersion stability, and particularly has a high polishing rate for silicon oxide films.

[0177] In one implementation example of the present invention, the polishing rate of the silicon oxide film of the slurry composition for chemical mechanical polishing can be or more, preferably or more, more preferably or more. The higher the polishing rate of the oxide film, the better. Therefore, there is no upper limit, but the polishing rate of the silicon oxide film is preferably or less, or less, or less, or less, or less, or or less. In particular, in the slurry composition for chemical mechanical polishing using the cerium oxide particles of one implementation example of the present invention, even when the cerium oxide particles are in a low content range, due to their small particle size, the number of particles contained is more than that of the slurry composition containing conventional cerium oxide particles, and the Ce 3+ content on the surface is high, increasing the Si-O-Ce bonds. Therefore, the polishing rate of the silicon oxide film can be significantly improved.

[0178] In one implementation example of the present invention, the slurry composition for chemical mechanical polishing may have a polishing selectivity ratio of oxide film / nitride film of 50 or more, 100 or more, 150 or more, or 200 or more, and may have a polishing selectivity ratio of oxide film / nitride film of 3,000 or less, 2,000 or less, 1,500 or less, 1,000 or less, 900 or less, or 800 or less. It is not excluded that the content of the cationic polymer can be appropriately adjusted to make the oxide film / nitride film selectivity ratio reach 3,000 or more.

[0179] The second embodiment of the present invention provides a method for manufacturing a semiconductor device, which includes a step of polishing using the slurry composition for chemical mechanical polishing.

[0180] The detailed description of the parts repeated with the first embodiment of the present invention is omitted, but the description content of the first embodiment of the present invention is equally applicable to the second embodiment.

[0181] Hereinafter, the method for manufacturing a semiconductor device according to the second embodiment of the present invention will be described in detail.

[0182] First, according to the routine process of shallow trench isolation (STI), in the process for planarization of the insulating film, photolithography, etching, and cleaning (polishing) can be classified as general basic processes.

[0183] To isolate devices, the photolithography process can be started as the first step. The photolithography process can be implemented on an auxiliary device called Track and an exposure machine that performs exposure to copy a circuit pattern (Mask) onto a wafer. First, a photosensitive agent (Photo Resistor) is applied. Since the viscosity of the photosensitive agent is high, it needs to be thinly coated on the insulating film while rotating the wafer. Only when the coated photosensitive agent is highly uniform will the photosensitive depth be appropriate. When exposure is performed, if the photosensitive depth is insufficient, photosensitive agent residues will be left during development, and in the subsequent etching process, the underlying film (insulating layer) cannot be smoothly removed. After photosensitization, the wafer is transferred back to the Track device to perform the development process of removing the photosensitive parts.

[0184] As the second step, the etching of STI is a process of removing the insulating layer (oxide layer + nitride layer) and a part of the substrate directly below the developed part (the part where the photosensitive film has been removed). The etching process can utilize dry or wet processes. The dry etching method is generally a method of etching using a plasma state. Compared with wet (liquid) etching, dry etching does not etch the sidewalls (anisotropic etching), but only etches the bottom, so it is beneficial for shaping the trench. At this time, over-etching may occur, so it is necessary to perform it after accurately calculating the etching end point. After etching, residues will be left, so they need to be processed.

[0185] After the trench shape is etched, the photosensitive agent layer is no longer useful, so it can be removed by ashing. Preferably, the ashing process is performed using plasma, whereby ashing can be performed more precisely. The shape of the semiconductor device after the ashing process is shown in Figure 2a in.

[0186] The method for manufacturing a semiconductor device according to an embodiment of the present invention may include a step of simultaneously polishing a silicon oxide film, a silicon nitride film, and a polysilicon film using the slurry composition for chemical mechanical polishing.

[0187] Figures 2a to 2e is a cross-sectional view showing a method for manufacturing a semiconductor device according to an embodiment of the present invention.

[0188] Refer to Figure 2a, grooves 13 can be formed in the upper film 11 on the lower film 10. As an example, the upper film 11 can be formed on the lower film 10, and a nitride film (etch stop film) 12 can be formed on the upper film 11. The lower film 10 can include any material film. For example, the lower film 10 can be an insulating film, a conductive film, a semiconductor film, or a semiconductor wafer (substrate). The upper film 11 can include an insulating film (oxide film), a conductive film, a semiconductor film, or a combination thereof.

[0189] When the upper film 11 includes a plurality of stacked insulating films, these insulating films can be of the same type or different types from each other. As an example, the upper film 11 can include a plurality of silicon oxide films and a plurality of silicon nitride films stacked alternately and repeatedly. The upper film 11 can further include a semiconductor film and a lower insulating film below the plurality of silicon oxide films and the plurality of silicon nitride films. For example, the lower insulating film can be disposed below the semiconductor film.

[0190] For example, silicon nitride (e.g., SiN), polysilicon, metal nitride (e.g., TiN), metal, etc. can be deposited so that the nitride film (etch stop film) 12 has a relatively large thickness (e.g., ). The grooves 13 can be formed by an etching process or a drilling process. The grooves 13 can have a depth that can penetrate the nitride film (etch stop film) 12 and the upper film 11 to reach the lower film 10. For example, the grooves 13 can have a depth sufficient to expose the lower film 10.

[0191] Referring to Figure 2b , in STI, the oxide film can be formed in a double structure. First, before the insulating material is officially filled into the grooves 13 that ensure the space, a linear (Liner) oxide film is thinly covered in a diffusion manner as the first insulating film 14. This is to smoothly form the second insulating film on the silicon substrate by CVD deposition in subsequent steps. According to another implementation example of the present invention, when filling the grooves 13 by high-density plasma CVD (HDP CVD), it can also play a role in avoiding damage caused by high-energy plasma. According to an implementation example of the present invention, the first insulating film (linear oxide film) can be formed by introducing oxygen into a diffusion furnace (Furnace) and heating it at a high temperature to form a thin film such as a gate oxide film. Additionally, according to another implementation example of the present invention, a nitride film can also be used instead of the oxide film.

[0192] Referring to Figure 2c, a plurality of insulators may be deposited to form a first insulating film 14 and a second insulating film 15 that fill the trench 13. The density and deposition rate of the first insulating film 14 and the second insulating film 15 may be different from each other. According to an embodiment of the present invention, the first insulating film 14 may be deposited from a high-density insulator, and the second insulating film 15 may be deposited from a low-density insulator. As an example, the first insulating film 14 may be deposited and patterned from a high-density plasma (HDP) oxide. The first insulating film 14 may be formed in a shape extending along the inner surface of the trench 13. For example, the first insulating film 14 may be in a U-shape or a tubular shape that opens upward.

[0193] Since the first insulating film 14 has a high density, it is difficult for voids to be generated in the first insulating film 14. Therefore, during subsequent heat treatment processes, cracks caused by voids can be prevented or significantly reduced. For example, the second insulating film 15 may be formed by filling the trench 13 in which the first insulating film 14 is formed with tetraethyl orthosilicate (TEOS) oxide and depositing it to a thickness sufficient to cover the polishing stop film 12. The second insulating film 15 can be formed at a deposition rate faster than that of the first insulating film 14. Due to the fast deposition rate of the second insulating film 15, the trench 13 can be filled with the second insulating film 15 relatively quickly.

[0194] According to another implementation example of the present invention, although not shown, a part of the second insulating film 15 may be removed so that the second insulating film 15 remains on the trench 13. For example, the second insulating film 15 may be selectively removed using a photolithography process and an etching process to define or open a specific area such as a cell storage area of a semiconductor device. Therefore, a part or all of the second insulating film 15 on the polishing stop film 12 can be removed, and the second insulating film 15 can remain on the trench 13. The opening process of the specific area can be selectively performed and is not necessary.

[0195] Referring to Figure 2d , a planarization process may be performed on the second insulating film 15. For example, the second insulating film 15 may be planarized by a chemical mechanical polishing (CMP) process. The chemical mechanical polishing process may be continued until the nitride film (polishing stop film) 12 is exposed. The chemical mechanical polishing process may be performed after the second insulating film 15 in Figure 2b is formed. At this time, 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 serious. Therefore, the chemical mechanical polishing process can be easily performed.

[0196] Next, referring to Figure 2e, the nitride film can be removed to form STI. The purpose of the nitride film is to protect the upper film 11 from the influence of the first insulating film 14. The upper film 11 can be a gate oxide film that requires thinness and high reliability, so careful operation is needed. When removing the nitride film by etching (wet process), the wafer can be immersed in a chemical solution so that only the nitride film is etched and the oxide film is not etched. For this purpose, a solution with a high selectivity ratio (etching ratio) for the nitride film can be used. In another implementation example of the present invention, the nitride film can be removed by CMP. At this time, there is no need to etch the nitride film, but physical damage may be caused to the oxide film. Therefore, it is preferably to chemically treat the nitride film by etching to protect the oxide film.

[0197] According to another implementation example of the present invention, in the chemical mechanical polishing (CMP) process, after gap filling, the first insulating film 14 and the second insulating film 15 above the nitride film (polishing stop film) 12 are all removed to separate the active region from the field region (isolation), as Figure 2f shown, the process can be roughly divided into three steps.

[0198] In the first step, the second insulating film 15 is coarsely polished (bulk CMP) on the platen to achieve local planarization. In the second step, the second insulating film 15 with alleviated steps is cleaned or polished on the platen, and the polishing is stopped when the nitride film (polishing stop film) 12 is exposed. At this time, an end point detection (EPD) can be used to sense the moment when different film materials are exposed. In the third step, the residue of the second insulating film 15 that may remain on the nitride film (polishing stop film) 12 can be removed on the platen, and the nitride film and the oxide film materials are polished for targeting.

[0199] Figure 2g The structure of a chemical mechanical polishing (CMP) device according to an implementation example of the present invention is shown. The device can have three platens. As described above, it can be a structure that sequentially passes through the 1st, 2nd, and 3rd platens for STI CMP polishing of each step. After the polishing is completed, it moves to the cleaning section, and after the cleaning is completed, the process is terminated.

[0200] In addition, in the manufacturing method of a semiconductor device according to an implementation example of the present invention, the method of simultaneously polishing a silicon oxide film, a silicon nitride film, and a polysilicon film using the slurry composition for chemical mechanical polishing can use the polishing methods and conditions commonly used in the prior art, and there are no special limitations in the present invention.

[0201] In one implementation example of the present invention, the slurry composition for chemical mechanical polishing has high dispersion stability. The Ce content on the surface of the cerium oxide particles contained in the slurry composition is high, and it is possible to improve the polishing rate for a silicon-containing substrate based on the chemical polishing mechanism of forming Si-O-Ce between silicon dioxide and cerium. Therefore, even under the condition of containing cerium oxide in a low content, it can be particularly effectively used for removing a silicon oxide film from the surface in the CMP process of semiconductor devices. 3+

[0202] The third embodiment of the present invention provides a semiconductor device, which includes: a substrate; and trenches located on the substrate and filled with an insulating material, wherein the trenches are formed by polishing at least one film selected from a silicon oxide film, a silicon nitride film, and a polysilicon film using a slurry composition for chemical mechanical polishing, and the slurry composition for chemical mechanical polishing contains cerium oxide particles, a solvent, a cationic polymer, and a nitride film polishing inhibitor.

[0203] Details of parts repeated with the first and second embodiments of the present invention are omitted, but the description contents of the first and second embodiments of the present invention are equally applicable to the third embodiment.

[0204] The fourth embodiment of the present invention provides a method for manufacturing cerium oxide particles for chemical mechanical polishing, which includes the following steps: preparing a raw material precursor; and pulverizing 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.

[0205] Details of parts repeated with the first to third embodiments of the present invention are omitted, but the description contents of the first to third embodiments of the present invention are equally applicable to the fourth embodiment.

[0206] In one implementation example of the present invention, the step of preparing a raw material precursor may be included. The raw material precursor may be any precursor substance that can manufacture cerium oxide particles as a product.

[0207] In one implementation example of the present invention, the step of pulverizing 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 may be included. The step of pulverizing cerium oxide particles in a solution containing the raw material precursor can be pulverized by, for example, a pulverization process, and the pulverization method can be determined within the common technical knowledge of those skilled in the art without limitation. The step of precipitating cerium oxide particles in a solution containing the raw material precursor to obtain a dispersion of cerium oxide particles for chemical mechanical polishing may further include the step of removing the supernatant; or a filtration step.

[0208] ​In particular, in one implementation example of the present invention, the overall process of particle synthesis can be carried out at room temperature and does not experience an alkaline pH. Therefore, it has the advantage of being able to achieve a high-energy efficiency manufacturing process while exhibiting the characteristics of the above-mentioned particles.

[0209] The above description of the present invention is exemplary, and those skilled in the art can understand that it can be easily implemented in other forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above-mentioned multiple embodiments are exemplary in all aspects and not restrictive. For example, each component described as a single type can also be implemented in a dispersed form, and similarly, multiple components described in a dispersed form can also be implemented in a combined form.

[0210] The scope of the present invention is defined by the appended claims, and all changes or variations derived from the meaning and scope of the claims and their equivalent scope are included in the scope of the present invention.

[0211] Industrial Applicability

[0212] According to an embodiment of the present invention, the manufactured cerium oxide particles, by increasing the proportion of Ce on the surface of cerium oxide, 3+ although having a small particle size, when included in a chemical mechanical polishing slurry composition, even at a low content, can have a high oxide film removal rate. When combined with the surface treatment agent disclosed in the present invention, by converting the surface zeta potential of the cerium oxide particles to a negative value, the uses such as nitride film polishing can be expanded, and compared with the case without adding additives, improved effects can be obtained simultaneously, thus having industrial applicability.

Claims

1. A slurry composition for chemical mechanical polishing, characterized in that, it comprises: cerium oxide particles; a solvent; a cationic polymer; and a nitride film polishing inhibitor, 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.

2. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, the polishing rate of the oxide film increases as the content of the cationic polymer increases.

3. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, the polishing rate of the nitride film decreases as the content of the nitride film polishing inhibitor increases.

4. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, based on the total weight of the slurry composition for chemical mechanical polishing, the content of the nitride film polishing inhibitor is 0.001 to 1% by weight.

5. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, based on the total weight of the slurry composition for chemical mechanical polishing, the content of the cationic polymer is 0.001 to 1% by weight.

6. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, the cationic polymer is poly(diallyldimethylammonium chloride), poly(diethylenetriamine-2-(dimethylamino)ethyl methacrylate), poly(2-(dimethylamino)ethyl methacrylate), polyacrylamide decamethylenediamine, dimethylamine-epichlorohydrin copolymer, poly(dimethylamine-co-epichlorohydrin-co-ethylenediamine) or a combination thereof.

7. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, the nitride film polishing inhibitor is a sulfonic acid substance, a cationic surfactant, an amphoteric surfactant or a combination thereof.

8. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, the nitride film polishing inhibitor is at least one sulfonic acid substance selected from poly(sulfonated styrene), benzenesulfonic acid, C1-4 alkylbenzenesulfonic acid, di-C1-4 alkylbenzenesulfonic acid, C5-10 alkylsulfonic acid or a salt thereof.

9. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, based on the total weight of the slurry composition for chemical mechanical polishing, the content of the cerium oxide particles is 0.001 to 5% by weight.

10. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, the slurry composition for chemical mechanical polishing further comprises a pH regulator, The pH regulator is an inorganic acid, an organic acid, an amino acid, imidazole, an alkylamine, an alkanolamine, a quaternary ammonium base, ammonia, or a combination thereof, wherein the inorganic acid is one or more selected from sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, the organic acid is one or more selected from acetic acid, citric acid, gluconic acid, glycolic acid, formic acid, lactic acid, malic acid, fumaric acid, maleic acid, oxalic acid, phthalic acid, succinic acid, and tartaric acid, and the amino acid is one or more selected from lysine, glycine, alanine, arginine, valine, leucine, isoleucine, methionine, cysteine, proline, histidine, phenylalanine, serine, tris(hydroxymethyl)methylglycine, tyrosine, aspartic acid, tryptophan, and aminobutyric acid.

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

12. The slurry composition for chemical mechanical polishing according to claim 1, wherein, The slurry composition for chemical mechanical polishing has a silicon oxide film polishing rate.

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

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

15. The slurry composition for chemical mechanical polishing according to claim 1, wherein, the primary particle size of the cerium oxide particles measured by a transmission electron microscope is 0.5 to 10 nm.

16. The slurry composition for chemical mechanical polishing according to claim 1, wherein, Based on X-ray photoelectron spectroscopy analysis, taking 100% of the total XPS peak area representing the Ce-O binding energy on the surface of the cerium oxide particles as a reference, the sum of the XPS peak areas of Ce 3+ with a Ce-O binding energy is 30% or more.

17. The slurry composition for chemical mechanical polishing according to claim 1, wherein, the cerium oxide particles are prepared by a step of obtaining a dispersion of particles by precipitation in a solution containing a raw material precursor and at an acidic pH.

18. A method for manufacturing a semiconductor device, wherein, it includes a step of polishing using the slurry composition for chemical mechanical polishing according to claim 1.

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