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 polycrystalline silicon polishing inhibitor, a silicon oxide film / polycrystalline silicon 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 polysilicon 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 scratch generation 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 is reduced, and thus, there is a problem of a decrease in the polishing rate.

[0005] Even if it is attempted 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 of the optimal level is not disclosed. Therefore, it is necessary to study the polishing slurry containing cerium oxide particles, and the cerium oxide particles increase the ratio of Ce 3+ on the surface of cerium oxide, and although the particle size is small, it can exhibit a high oxide film removal rate.

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

[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 oxide film polishing rate obtained by precipitation in a solution is greatly increased, and by combining the cerium oxide particles with optimized conditions with additives, a slurry composition has been developed that greatly increases the silicon oxide film polishing rate while passivating and adjusting the fine pattern of the polysilicon film quality, thereby 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 polysilicon polishing inhibitor. In the 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 polysilicon film can decrease as the content of the polysilicon polishing inhibitor increases.

[0017] Based on the total weight of the slurry composition for chemical mechanical polishing, the content of the polysilicon 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 polysilicon polishing inhibitor can be a cationic surfactant, a monomolecular surfactant, a substance containing a hydrophobic functional group, or a combination thereof.

[0021] The polysilicon polishing inhibitor may be the single-molecule cationic surfactant, and may include at least one selected from cetylpyridinium chloride (CTC), behentrimonium chloride (BTAC-228), benzalkonium chloride (BZK), benzododecinium bromide, cetalkonium chloride (CKC), cetrimonium bromide (CTAB), cetrimonium chloride, didecyldimethylammonium chloride (DDAC), dimethyldioctadecylammonium bromide (DODAB), dimethyldioctadecylammonium chloride (DODAC), and stearalkonium chloride.

[0022] The slurry composition for chemical mechanical polishing may further include a pH regulator, and the pH regulator 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, 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.

[0023] The pH value of the slurry composition for chemical mechanical polishing may be 2 to 10.

[0024] The slurry composition for chemical mechanical polishing may have a silicon oxide film polishing rate.

[0025] The slurry composition for chemical mechanical polishing may have a polishing selectivity of oxide film / polysilicon film of 200 to 2,000.

[0026] The secondary particle size of the cerium oxide particles measured using a dynamic light scattering particle size analyzer (DLS) may be 1 to 20 nm.

[0027] The primary particle size of the cerium oxide particles measured using a transmission electron microscope (TEM) may be 0.5 to 10 nm.

[0028] 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.

[0029] The cerium oxide particles can be produced by a step of obtaining a dispersion of particles by precipitation in a solution containing a raw material precursor at an acidic pH.

[0030] 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.

[0031] Advantageous Effects

[0032] According to an embodiment of the present invention, the produced cerium oxide particles, by increasing the proportion of Ce on the surface of cerium oxide, although having a small particle size, when included in a slurry for chemical mechanical polishing, even at a low content, can have a high oxide film removal rate. At the same time, it can be confirmed that by adding the cationic polymer in the present invention, the polishing rate of the oxide film can be further increased, and at the same time, by using a polysilicon polishing inhibitor, the selectivity ratio of the oxide film / polysilicon film can be increased, and thus, fine patterns can be passivated. In view of the fact that the addition of a cationic polymer is usually common technical knowledge for ensuring other properties while sacrificing the polishing rate, this can be regarded as a unique effect of the present invention. 3+ In addition, according to an embodiment of the present invention, it is possible to provide cerium oxide particles for chemical mechanical polishing and a slurry composition for chemical mechanical polishing 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 to be a trade-off relationship in the prior art, can minimize surface defects while maximizing the oxide film removal rate.

[0033] 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.

[0034] Brief Description of the Drawings Brief Description of the Drawings

[0035] Figure 1It is a diagram showing the oxide film removal mechanism of an embodiment of the present invention.

[0036] Figures 2a to 2e It 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 It shows the step process of chemical mechanical polishing and the structure of a chemical mechanical polishing (CMP) device according to another implementation example of the present invention, respectively.

[0037] Figure 3 It 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.

[0038] Figure 4 It is a transmission electron microscope (TEM) image of cerium oxide particles according to an embodiment of the present invention.

[0039] Figure 5 It shows scanning electron microscope (SEM) and transmission electron microscope (TEM) images of existing cerium oxide particles of a comparative example.

[0040] Figure 6 It shows a TEM image of existing cerium oxide particles of a comparative example.

[0041] Figure 7 It is the result of measuring cerium oxide particles according to 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 of Malvem Corporation.

[0042] Figure 8 It is the X-ray diffraction (XRD) analysis result of cerium oxide particles according to an embodiment of the present invention.

[0043] Figure 9 It is the XPS analysis result of cerium oxide particles according to an embodiment of the present invention and existing cerium oxide particles of 60 nm level.

[0044] Figure 10 It is the FT-IR spectral analysis result of a powder composed of cerium oxide particles manufactured according to an implementation example of the present invention and a powder composed of conventional cerium hydroxide particles.

[0045] Figure 11 It is the FT-IR spectral analysis result 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.

[0046] Figure 12The results are the results of measuring the light transmittance of the slurry including the cerium oxide particles according to one embodiment of the present invention and the slurries including the conventional cerium oxide particles of Comparative Examples 1 to 4 using ultraviolet-visible light (UV-Vis) spectrophotometry.

[0047] Figure 13 The effect of adding a cationic polymer on the polishing rate of an oxide film according to an embodiment of the present invention is shown.

[0048] Figure 14 It is shown that since the adsorption amount of TEOS to the silicon oxide film is higher than that to the polysilicon film, when an appropriate amount is used, the polishing speed of TEOS is increased and the polishing speed of the polysilicon film is decreased.

[0049] Figure 15 and Figure 16 The images are scanned before and after CMP of an oxide wafer using a CMP slurry composition including cerium oxide particles according to an embodiment of the present invention and a CMP slurry composition including cerium oxide particles having a size of 60 nm. DETAILED DESCRIPTION

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

[0051] In addition, the terms used in the present invention are only used to illustrate 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 statement to the contrary, "including" a certain constituent element in the entire specification of the present invention does not mean excluding other constituent elements, but means that other constituent elements may be further included.

[0052] The "monodisperse" used in the present invention means that when the cerium oxide particles are dispersed in the slurry, they are suppressed from agglomerating into secondary particles, thereby relatively maintaining the primary particle size, which means that the secondary particle size (D50) measured by dynamic light scattering (DLS) is 3.0 times or less, 2.8 times or less, 2.5 times or less, 2.2 times or less, 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., it is not excluded that the inevitable impurities with relatively coarse size are included.

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

[0054] A 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 a substrate, and is typically 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 than 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 throughput of the equipment. However, when the removal rate of the capping layer is too fast, the trenches will be corroded due to over-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 a variety of 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 in a bottom-up manner. In an embodiment 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 was added to a sufficient amount of deionized water and stirred. Nitric acid was added to the precursor solution to adjust the pH value to less than 1.0. Ammonia water was added to the resulting mixture and stirred until a precipitate was formed. It was confirmed that the pH of the stirred mixture was strongly acidic (2 or less), and if left standing after stirring was complete, the product would precipitate rapidly. After removing the supernatant other than the precipitate, a specified amount of deionized water was added to generate a pale yellow cerium oxide particle dispersion. The resulting dispersion was 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 below 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 produced yellow transparent cerium oxide dispersion to precipitate, it is filtered by circulating 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 - 4 kg of ammonium cerium nitrate is added to a sufficient amount of ethanol and stirred. An alkaline 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 (2 or below), and if left standing after the stirring is completed, the product will precipitate rapidly. After removing the supernatant other than the precipitate, a specified amount of deionized water is added to form a cerium oxide particle dispersion. The produced dispersion is filtered by circulating 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 light purple large particles dissociate and yellow transparent cerium oxide nanoparticles are formed. 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-mentioned Manufacturing Example 1 are added to deionized water, the concentration of the abrasive is adjusted to 0.05 wt%, and triethanolamine is added to adjust the pH value to 5.5, thereby manufacturing a CMP slurry.

[0066] According to Figure 3 , the turbidity of the slurry containing the existing cerium oxide particles is high and 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] Production Example 3. Production of CMP Slurry Containing Additives

[0068] The cerium oxide particles produced in the above Production Example 1 were added to deionized water, and the concentration of the abrasive was adjusted to 0.05 wt%, 0.001% of the cationic polymer and polysilicon polishing inhibitor in Table 1 were added respectively, 0.5% of polyethylene glycol 1000 was added, and triethanolamine was added to adjust the pH value to 5.8, thereby obtaining a CMP slurry. The composition is shown in Table 1.

[0069] Table 1:

[0070]

[0071] Comparative Examples 1 to 4. Production of Slurry Compositions Containing Conventional Cerium Oxide Particles

[0072] Commercially available wet-process cerium oxide particles with average particle sizes of 10 nm, 30 nm, and 60 nm respectively were added to deionized water, the concentration of the abrasive was adjusted to 0.05 wt%, and ammonia was added as a pH regulator to adjust the final pH value to 5.8, thereby producing a CMP slurry. The composition is shown in Table 2.

[0073] Table 2:

[0074]

[0075]

[0076] Experimental Example 1. SEM and TEM Analysis of Cerium Oxide Particles

[0077] The dispersion liquid of Production Example 1 of an 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). 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 with a TEM measuring instrument.

[0078] Figure 4 is a TEM image of the cerium oxide particles of an embodiment of the present invention.

[0079] Referring to Figure 4 , the TEM measurement results of the cerium oxide particles prepared according to an embodiment of the invention show that 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 seen 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.

[0080] Figure 5 SEM and TEM images of the existing cerium oxide particles of the comparative example are shown.

[0081] Referring to Figure 5 , the existing commercially available cerium oxide particles have particle diameters corresponding to each size class. All the particles separately prepared by the calcination method have a primary particle diameter greater than 10 nm on average. It can be confirmed that compared with the average particle diameter measured by TEM of the cerium oxide particles of one embodiment of the present invention shown in Figure 4 which is 4 nm or less, the cerium oxide particles in the prior art and the cerium oxide particles prepared by the conventional calcination method have significantly coarser particle diameters. On the contrary, it has been confirmed that the particle diameter (primary particle) of the cerium oxide particles of the present invention is formed small, and it can be predicted that the smaller the cerium oxide particle diameter, the more the defects such as scratches generated on the surface of the film to be polished can be reduced.

[0082] In addition, Figure 6 TEM images of the existing cerium oxide particles of the comparative example are shown. Referring to Figure 6 , it can be confirmed that the cerium oxide particles in the prior art with a particle diameter of 10 nm or less include particles with edges and spherical particles, and the cerium oxide particles in the prior art with a particle diameter 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. Since the cerium oxide particles of the present invention have a spherical particle shape and a small particle diameter, a large number of particles can be included. Therefore, the probability of surface defects generated during polishing of the silicon oxide film can be reduced, and the global flatness can be improved.

[0083] Experimental Example 2. Analysis of Cerium Oxide Particles by Dynamic Light Scattering (DLS) Analyzer Scattering, DLS

[0084] Prepare the slurry composition of Production Example 2 of one 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 above-prepared samples respectively using a DLS device.

[0085] Figure 7 is the result of dynamic light scattering (DLS) analysis (Malvern Corporation, Zetasizer Ultra) of the cerium oxide particles of one embodiment of the present invention. In addition, Table 3 shows the D50 values of the cerium oxide particles of one embodiment of the present invention and the cerium oxide particles of multiple comparative examples obtained based on dynamic light scattering (DLS) analysis.

[0086] Table 3:

[0087]

[0088] Referring to Figure 7 and Table 3, upon measurement, the cerium oxide particles of the embodiments 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 (referring to Figure 4 ), it is 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.

[0089] On the contrary, the D50 particle size of the cerium oxide particles in the prior art measured by dynamic light scattering (DLS) is greater than 30 nm, and relative to the primary particle size measured by TEM, the D50 value of the secondary particle size of the 10 nm-class cerium oxide particles measured by dynamic light scattering (DLS) is about 336%. The cerium oxide particles in the prior art have a significantly larger secondary particle size, and thus it can be confirmed that a large amount of aggregation has occurred.

[0090] In particular, it can be confirmed that, as predicted by the inventors of the present invention, the secondary particle size of the cerium oxide particles of 10 nm or less prepared by the supercritical hydrothermal synthesis method or the wet method under alkaline conditions is significantly larger than the primary particle size.

[0091] In addition, it was confirmed that even when containing a polysilicon polishing inhibitor and a cationic polymer (Example 2) as additives, the monodispersity of the cerium oxide particles in the slurry could be maintained. Therefore, it was confirmed that the cationic polymer and the polysilicon polishing inhibitor in the present invention are suitable for use in combination with the cerium oxide particles of one embodiment of the present invention.

[0092] 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.

[0093] Experimental Example 3. X-ray Diffraction (XRD) Analysis of Cerium Oxide Particles

[0094] 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 apparatus (Rigaku, Ultima IV). At this time, the XRD was set to Cu Kα under the conditions of 40 kV and 40 mA.

[0095] Figure 8 is the X-ray diffraction (XRD) analysis result of the cerium oxide particles of one embodiment of the present invention.

[0096] The Sample A was subjected to XRD analysis, and as a result, the following was obtained as shown in Figure 8XRD spectrum of the morphology shown (X-axis: 2-theta (degrees), Y-axis: intensity). The crystallite size calculated based on the spectrum is 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.

[0097] Experimental Example 4. XPS Analysis of Cerium Oxide Particles

[0098] Figure 9 is the XPS analysis result 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 that appear 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, thereby measuring the content of Ce 3+ and Ce 3+ and Ce 4+ in the cerium oxide particles. Table 4 is the XPS result data of the cerium oxide particles of the embodiments of the present invention.

[0099] Table 4:

[0100]

[0101] Based on the above XPS analysis results, it can be seen 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 the cerium oxide particles, Ce 3+ is the reactive sites, so the grinding amount can be increased. In the above manner, the comparison data with the cerium oxide particles in the prior art are shown in Table 5 together.

[0102] Table 5:

[0103]

[0104] As shown in Table 5, the content of Ce 3+ of the cerium oxide particles of an embodiment of the present invention is about 36.9 atomic %, and it can be seen from Table 5 that compared with the Ce 3+The content is less than 14 atomic percent (atomic %), and compared with about 16.8% of cerium oxide particles with a size of 10 nm level recorded in the existing literature and prepared by hydrothermal synthesis method under supercritical or subcritical conditions, it has a higher Ce 3+ content. When having a high level of surface Ce 3+ content as in the embodiments of the present invention, the polishing rate for a silicon-containing substrate can be improved through the chemical polishing mechanism of forming Si-O-Ce between silica and cerium.

[0105] Experimental Example 5. Confirmation of the Formation of Cerium Oxide Particles by Fourier Transform Infrared (FT-IR) Spectral Analysis

[0106] Figure 10 are the FT-IR spectroscopic analysis results of the powder composed of cerium oxide particles made according to an embodiment 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 - 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 - 4100 cm-1, scanning was repeated more than once to draw a curve graph (in the FT-IR spectrum, the wave number (cm-1) may have an error range of ±10 cm-1).

[0107] According to Figure 10 the analysis results of the FT-IR spectrum, the infrared transmittance of the powder composed of cerium oxide particles of an embodiment of the present invention is about 92% - 93% in the range of 3000 cm-1 - 3600 cm-1, and about 93% - 95% in the range of 720 cm-1 - 770 cm-1. In the FT-IR spectrum of the powder composed of conventional cerium hydroxide particles, the infrared transmittance is 75% - 90% in the range of 3000 cm-1 - 3600 cm-1 and 97% - 99% in the range of 720 cm-1 - 770 cm-1. 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 - 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 - 770 cm-1. Therefore, this result can indicate that the cerium compound made according to an embodiment of the present invention is cerium oxide.

[0108] As a comparative example, among the cerium oxide particles synthesized by the wet method similarly to an embodiment 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 Figure 11As for the results of this experiment shown, when the particles synthesized under alkaline pH conditions are measured for FT-IR immediately after synthesis, peaks in the ranges of 3000 cm-1 to 3600 cm-1 and 720 cm-1 to 770 cm-1 indicating cerium hydroxide still appear. Figure 10 Multiple main peaks of cerium hydroxide in Figure 10 thus make it difficult to consider that it contains only cerium oxide.

[0109] Experimental Example 6. Measurement of the Transmittance of Slurry Containing Cerium Oxide Particles

[0110] 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 (Sample B1, B2, B3, and B4 in order) were prepared in the same manner as in Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, respectively, except that the weight ratio of cerium oxide particles in the CMP slurry was 1% by weight. Using a UV-Vis spectrophotometer (JASCO), the transmittance of each sample for light in the range of 200 to 1100 nm was measured.

[0111] Figure 11 are the results of the transmittance measured by ultraviolet-visible (UV-Vis) spectrophotometry for the slurry containing cerium oxide particles of one embodiment of the present invention and the slurries containing existing cerium oxide particles of Comparative Example 1 to Comparative Example 4.

[0112] Cerium oxide particles of one 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).

[0113] Through the above UV-Vis analysis spectrum, the transmittance (%) of Sample A, A2, and Sample B1 to B4 at wavelengths of 500 nm, 600 nm, and 700 nm were sorted out and shown in Table 6.

[0114] Table 6:

[0115]

[0116] According to Figure 11 and Table 6, it can be confirmed that the average transmittance of the slurry containing the cerium oxide particles of the present invention for light with a wavelength of 450 to 800 nm is 50% or more. In addition, it can be confirmed that the transmittance for light with a wavelength of about 500 nm is 90% or more, and the transmittance for light with wavelengths of about 600 nm and 700 nm is 95% or more.

[0117] Conversely, the light transmittance of slurries containing cerium oxide particles in the prior art, namely Comparative Examples 1 to 4 (existing cerium oxide particles of 10 nm level, 30 nm level, 60 nm level, and cerium oxide particles based on the calcination method), was 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 cerium oxide particles of 10 nm level in the prior art 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%.

[0118] Conversely, the light transmittance of the cerium oxide particles of an embodiment of the present invention in the visible light region is more than 90%, which means that the size of the primary particles of the cerium oxide particles of the present invention is tiny by itself, and compared with the cerium oxide particles in the prior art, they are less aggregated into secondary particles. Generally, when the secondary particles are larger than 20 nm, the slurry composition can be observed to be opaque to the naked eye, and the light transmittance for the wavelengths in the visible light region is less than 80%.

[0119] 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 polishing rate is excellent, and the particles themselves are tiny. Therefore, when the slurry composition containing the particles is used to polish the film to be polished, it is obvious that the probability of surface defects such as scratches is reduced.

[0120] In addition, it can be confirmed that even when a cationic polymer and a polysilicon polishing inhibitor are contained as additives, the light transmittance characteristics of the present invention remain at the same level. However, when the additives are selected incorrectly, 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 polysilicon polishing inhibitor selected in the present invention can meet the required characteristics without impairing the basic characteristics of the particles in the slurry.

[0121] Experimental Example 7. Comparison of the Oxide Film Polishing Rates of Cerium Oxide Particles

[0122] 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 were respectively prepared as samples.

[0123] The polishing of the oxide film wafer using the above samples was performed using a polishing machine ( LK CMP, Applied Materials). Specifically, a PE-TEOS silicon oxide film wafer (300mm PE-TEOS Wafer) was installed on a grinding disc (Platen), and the surface of the wafer was contacted with the pad of the grinder (IC1010, DOW). Next, a slurry composition as a sample was supplied at a speed of 200mL / min, and the grinding disc (Platen) and the pad of the grinder were rotated to perform a grinding process. At this time, the rotation speed of the grinding disc and the rotation speed of the head (Head) were 67rpm / 65rpm, the grinding pressure was 2psi, and the grinding time was 60 seconds. On the other hand, the silicon oxide film thickness of the wafer was measured using ST5000 (Spectra Thick 5000ST, K-MAC). The results are shown in Table 7.

[0124] Table 7:

[0125]

[0126] As shown in Table 7, when the slurry composition of the embodiment is used, the silicon oxide film removal rate is about 6 times or more than that of the slurry compositions of the comparative examples. This is because the particle size of the cerium oxide particles contained in the slurry composition of the embodiment is small, so the number of particles effectively used for polishing is large relative to the content, and the Ce on the surface is 3+ The content (molar ratio and / or weight ratio) of is high, thereby improving the chemical reactivity with the surface of the silicon oxide film.

[0127] In addition, it can be confirmed that the slurry composition of Manufacturing Example 3 further comprising a cationic polymer and a polysilicon polishing inhibitor further improves the oxide film polishing rate compared to the slurry composition of Manufacturing Example 2 that does not contain multiple additive substances. It can be seen that when the cationic polymer of an implementation example of the present invention is combined with the cerium oxide particles of an implementation example of the present invention, the cationic polymer is arranged between the multiple cerium oxide particles of an implementation example of the present invention, which can further improve the unique monodispersity, thereby maximizing the number and area of ​​particles in contact with the silicon oxide film. Therefore, it can be considered that within a predetermined content range, the oxide film polishing rate will be increased. When the predetermined range is exceeded, the depression regulator itself may block or hinder the cerium oxide particles from contacting a portion of the oxide film, thereby reducing the oxide film polishing rate. This operation of the oxide film polishing rate based on the content of the cationic polymer is characteristic, and when conventional cerium oxide particles are used together with a cationic polymer such as that described in the present invention, it is the opposite of the decrease in the oxide film polishing rate observed from the initial content. This characteristic is briefly shown in Figure 13 middle.

[0128] Experimental Example 8. Defect Evaluation of Cerium Oxide Particles

[0129] Figure 15 and Figure 16 are images obtained by scanning an oxide wafer before and after CMP using a CMP slurry composition containing cerium oxide particles according to an embodiment of the present invention and a CMP slurry composition containing cerium oxide particles with a size of 60 nm.

[0130] Surface analysis of the oxide wafer was performed in a full wafer scan mode using an AIT-XP device.

[0131] Referring to Figure 15 and Figure 16 , after performing CMP on the surface of an oxide wafer using a CMP slurry composition containing cerium oxide particles according to an embodiment of the present invention, the results of analyzing the surface of the oxide wafer before and after CMP showed that the number of defects before CMP was 6 and the number of defects after CMP was 1. Therefore, after performing CMP using an embodiment of the present invention, the defects on the surface of the oxide wafer were reduced. Additionally, no scratches were generated on the surface of the wafer during the CMP process. Conversely, after performing CMP on the surface of an oxide wafer using a CMP slurry composition containing cerium oxide particles in the prior art, the results of analyzing the surface of the oxide wafer before and after CMP showed that compared to 34 defects before CMP, the number of defects after CMP increased to 64, indicating that the cerium oxide particles in the prior art left scratches on the surface of the wafer. This shows that since the particle size of the cerium oxide particles according to 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 reasonably inferred that the cerium oxide particles according to an embodiment of the present invention are monodispersed in the slurry and are themselves tiny particles, so even if additives are included, defects can be minimized.

[0132] Experimental Example 9. Analysis of the Polishing Selectivity Ratio of Oxide Film / Polysilicon Film Depending on the Addition of Additives

[0133] After adding cerium oxide particles manufactured according to an embodiment of the present invention to deionized water and adjusting the pH value to 5.8, a cationic polymer was added as recorded in Table 8, and the polishing rate of the oxide film and the polishing rate of the polysilicon film were measured under the same polishing conditions as in Experimental Example 7. and the polishing rate of the polysilicon film

[0134] Table 8:

[0135]

[0136]

[0137] Referring to Table 8, it can be confirmed that when the cationic polymer and the polysilicon polishing inhibitor of one embodiment of the present invention are included, compared with the case without additives, the polishing rate of the polysilicon film quality in the STI process is significantly reduced. This effect is obtained while not damaging the characteristics of the particles of one 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 one embodiment of the present invention on the silicon oxide film (TEOS) is higher than that on the polysilicon film. Therefore, when used in an appropriate amount, the polishing rate of TEOS is increased while the polishing rate of the polysilicon film is reduced. In addition, it is known that when the cationic polymer of one embodiment of the present invention is added, it has the characteristic of reducing the polishing rate of the polysilicon film.

[0138] Embodiment

[0139] The 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 polysilicon 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.

[0140] Hereinafter, the slurry composition for chemical mechanical polishing according to the first embodiment of the present invention will be described in detail.

[0141] Figure 1 is a diagram showing the oxide film removal mechanism of one embodiment of the present invention. As Figure 1 shown, only the Ce 3+ ions on the surface of the cerium oxide particles can react smoothly with SiO2 after being activated.

[0142] In one embodiment of the present invention, by including the cationic polymer and the polysilicon polishing inhibitor, the polishing rate of the polysilicon film 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 showing a unique effect. Therefore, it will be described in detail below.

[0143] In one embodiment 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 recesses 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 the prior art polishing slurries, cationic polymers are added to improve dispersion stability or to protect the field oxide layer 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 increase the overall polishing rate for the oxide film as the amount of the cationic polymer added increases.

[0144] As described below, the cerium oxide particles of one embodiment of the present invention are obtained by a wet method at an acidic pH and are obtained in the form of a dispersion. Even if a solvent is directly added thereto to prepare a slurry, the ultra-fine cerium oxide nanoparticles can have a monodispersed form without an additional redispersion process, and the Ce content on the surface also remains in a high state, and it is a particle having a high oxide film polishing rate when manufactured into a slurry composition for chemical mechanical polishing. As described above, the inventors of the present invention have confirmed through research that even if various additives used in the prior art are added to the cerium oxide particles of one embodiment of the present invention having 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 various substances for specific nanoparticles to achieve the desired characteristics or performance. The slurry composition of one embodiment of the present invention can further add a polysilicon polishing inhibitor to minimize the polishing rate of the polysilicon film quality while not impairing (but rather improving) the excellent oxide film polishing rate performance of the cerium oxide particles. 3+ In one embodiment of the present invention, the principle of action of the unique cerium oxide particles, the cationic polymer, and the polysilicon polishing inhibitor substance of the present invention is 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 contact the silicon oxide film evenly and smoothly, thereby maximizing the polishing rate. In addition, the polysilicon polishing inhibitor can act to prevent the cerium oxide particles from contacting the polysilicon film quality, thereby minimizing the polishing rate of the polysilicon film. When used in an appropriate amount, it does not prevent the polishing rate of the silicon oxide film.

[0145]

[0146] ​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 cationic polymer may be 0.001% by weight or more, 0.002% by weight or more, 0.003% by weight or more, 0.004% by weight or more, or 0.005% by weight or more, and may be 1% by weight or less, 0.5% by weight or less, 0.1% by weight or less, 0.05% by weight or less, 0.03% by weight or less, 0.01% by weight or less. When, based on the total weight of the slurry composition for chemical mechanical polishing, the content of the cationic polymer is less than 0.001%, the content is too small to sufficiently act as an oxidation film polishing promoter, and thus cannot affect the polishing rate of the oxidation film. On the contrary, when it is greater than 1%, the added cationic polymer will hinder the polishing process of cerium oxide, instead reducing the polishing rate of the oxidation film, or becoming an impurity in the slurry composition.

[0147] 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 polysilicon polishing inhibitor may be 0.001% by weight or more, 0.002% by weight or more, 0.003% by weight or more, 0.004% by weight or more, or 0.005% by weight or more, and may be 1% by weight or less, 0.5% by weight or less, 0.1% by weight or less, 0.05% by weight or less, 0.03% by weight or less, 0.01% by weight or less. When, based on the total weight of the slurry composition for chemical mechanical polishing, the content of the polysilicon polishing inhibitor is less than 0.001%, the content is too small to sufficiently act as a polysilicon polishing inhibitor, and thus cannot affect reducing the polishing rate of the polysilicon film quality. When it is greater than 1%, the added polysilicon polishing inhibitor will hinder the polishing process of cerium oxide, instead reducing the polishing rate of the oxidation film, or becoming an impurity in the slurry composition.

[0148] 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.

[0149] In one implementation example of the present invention, the polysilicon polishing inhibitor may be a single molecule of the cationic surfactant, and may include at least one selected from cetylpyridinium chloride (CTC), behentrimonium chloride (BTAC-228), benzalkonium chloride (BZK), benzododecinium bromide, cetalkonium chloride (CKC), cetrimonium bromide (CTAB), cetrimonium chloride, didecyldimethylammonium chloride (DDAC), dimethyldioctadecylammonium bromide (DODAB), dimethyldioctadecylammonium chloride (DODAC), and stearalkonium chloride. 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.

[0150] In one 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. Since the Zeta potential value of the cerium oxide particles is positive, the polarity of the surface of the silicon oxide film is rendered negative. Therefore, the polishing efficiency is improved due to the attractive force between the cerium oxide particles and the surface of the silicon oxide film.

[0151] In one implementation example of the present invention, the hardness of the cerium oxide particles is lower than that of the silicon dioxide particles or the aluminum oxide particles. However, based on the chemical polishing mechanism of forming Si-O-Ce bonds between silicon dioxide and cerium, the polishing rate for the surface containing silicon such as a glass or semiconductor substrate is very fast. Therefore, it is beneficial for the polishing of the semiconductor substrate.

[0152] 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 known to those skilled in the art. Preferably, a particle size analyzer of Anton Parr company or ZetasizerUltra of Malvern company is used for measurement, but this is only an example and is not limited thereto. The above-mentioned secondary particles are formed by the aggregation of primary particles described later in the slurry. It can be seen that the larger the surface area of the particles, the larger the range of the gravitational action, so they are prone to aggregation. 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 aggregate. As disclosed in many prior arts, the isoelectric point pH value of cerium oxide particles is about 7. When 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.

[0153] 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 aggregate in the slurry composition, and at this time, it is difficult to be regarded as a monodisperse slurry. When the secondary particle size is less than the above range, the polishing speed of the target film is excessively reduced, resulting in a reduction in polishing efficiency.

[0154] 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 a transmission electron microscope (TEM) 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 (TEM) can be 0.5 to 10 nm, preferably 1 to 10 nm, and more preferably 2 to 9 nm.

[0155] 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.

[0156] Formula 1:

[0157] a ≤ 2.2b

[0158] 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.

[0159] In one 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 one implementation example of the present invention, the particle size of the cerium oxide particles measured by X-ray diffraction (XRD) 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 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 one 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.

[0160] In one 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, 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 one 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, 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.

[0161] Chemical Formula 1:

[0162] Ce 3+ content (%) = (Ce 3+ peak area) / [(Ce 3+ peak area) + (Ce 4+ peak area)]

[0163] In one 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.

[0164] 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%.

[0165] 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 the value 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.

[0166] That is, in one 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 can 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 can 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.

[0167] The cerium oxide particles of one implementation example of the present invention have the characteristic of high Ce content on the particle surface 3+ because, according to one implementation example of the present invention, the process of particle synthesis in the liquid phase by the wet process is carried out under acidic conditions. Generally, a cerium precursor substance containing trivalent cerium maintains the cerium trivalent state at acidic pH. In the manufacturing method of one implementation example of the present invention, the overall process of particle synthesis does not include conversion to alkaline pH. Therefore, the content of cerium trivalent on the surface of the synthesized particles is high. The characteristic of the cerium trivalent content 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 content on the particle surface of the cerium oxide particles of one implementation example of the present invention is high. When the content of Ce on the surface 3+ is relatively high, the polishing rate of the oxide film can be improved. 3+ content is relatively high, it can improve the oxide film polishing rate.

[0168] In one implementation example of the present invention, when Fourier - transformation infrared (FT - IR) spectroscopy is performed on the powder composed of the cerium oxide particles, in the spectrum specific to the FT - IR spectroscopy, 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 - mentioned 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 representing the infrared transmittance within the above - mentioned range, which can indicate that Ce - O stretching occurs within the above - mentioned 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 will be 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 will be detected.

[0169] In one implementation example of the present invention, the cerium oxide primary particles can be one or more selected from spherical, cubic, tetragonal, orthorhombic, rhombohedral, monoclinic, hexagonal, triclinic, and cuboctahedron shapes, and spherical particles are preferred.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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., thus affecting the aggregation 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, and the fine particles or nuclei will aggregate quickly. At this time, the magnitudes of the surface repulsive forces between the fine particles or nuclei are all similar, so they can aggregate with a uniform size. The secondary particles aggregated in this way are formed by the primary fine particles or nuclei growing into larger-sized particles through particle coalescence processes such as stronger aggregation or Ostwald ripening according to reaction conditions such as temperature and concentration.

[0174] 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.

[0175] Hereinafter, a slurry composition for chemical mechanical polishing containing the cerium oxide particles and a polysilicon polishing inhibitor according to an embodiment of the present invention will be described in detail.

[0176] 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 value of the light transmittance 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 per se, and compared with the cerium oxide particles in the prior art, they aggregate less into secondary particles. 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 surface defects such as scratches 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 when further containing the cationic polymer and the polysilicon polishing inhibitor as additives, this light transmittance characteristic can be maintained.

[0177] 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 cerium oxide particles may be 5% by weight or less. In another implementation example of the present invention, based on the total 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 a slurry with the same polishing rate, even if a lower content of the cerium oxide particles is added based on the total weight of the slurry composition for chemical mechanical polishing, a higher polishing efficiency of the oxide film can be achieved.

[0178] 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, the polishing rate, the polishing selectivity ratio, etc. The pH regulator for adjusting the pH may use a pH regulator that can adjust the pH without affecting the properties 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.

[0179] In an implementation example of the present invention, the pH regulator can 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, malic 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 can be triethanolamine, tetramethylammonium hydroxide (TMAH or TMAOH), or tetraethylammonium hydroxide (TEAH or TEA-OH). Additionally, the pH regulator can be, for example, one or more selected from ammoniummethylpropanol (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 can be triethanolamine or aminobutyric acid.

[0180] In an implementation example of the present invention, the solvent can be any solvent used in the slurry composition for chemical mechanical polishing. For example, deionized water can be used, but the present invention is not limited thereto. Additionally, ultrapure water is preferably used. The content of the solvent can be the remaining content in the total amount of the slurry composition for chemical mechanical polishing after removing the content of the cerium oxide particles and other additional additives. In an implementation example of the present invention, the solvent includes water (such as 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 (such as 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.

[0181] In one embodiment 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 polyurethanes), biocides (e.g., KATHON TM LX), etc.

[0182] In one embodiment 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.

[0183] In one embodiment of the present invention, the polishing rate of the silicon oxide film of the slurry composition for chemical mechanical polishing may 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 embodiment 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, so that the Si-O-Ce bonds increase. Therefore, the polishing rate of the silicon oxide film can be significantly improved.

[0184] 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.

[0185] Details of parts repeated with the first embodiment of the present invention are omitted, but the description of the first embodiment of the present invention also applies to the second embodiment.

[0186] Hereinafter, the method for manufacturing a semiconductor device according to the second embodiment of the present invention will be described in detail.

[0187] First, in the process for planarization of the insulating film according to the conventional (Routine) process of shallow trench isolation (STI), photolithography, etching, and cleaning (polishing) can be classified as general basic processes.

[0188] To separate the device, the lithography process can be started as the first step. The lithography 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 lower film (insulating layer) cannot be smoothly removed. After photosensitization, the wafer is moved back to the Track device to perform the development process of removing the photosensitive part.

[0189] As the second step, the etching of STI is a process of removing a part of the insulating layer (oxide layer + nitride layer) and the substrate directly below the developed part (the part where the photosensitive film has been removed). The etching process can use dry or wet processes. The dry etching method is usually 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. Residues will be left after etching, so they need to be processed.

[0190] After the trench shape is etched, the photosensitive agent layer is no longer useful, so it can be removed by ashing. Preferably, plasma is used for the ashing process, so that ashing can be performed more precisely. The shape of the semiconductor device after the ashing process is shown in Figure 2a in.

[0191] The manufacturing method of the 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.

[0192] Figures 2a to 2e is a cross-sectional view showing the manufacturing method of the semiconductor device according to an embodiment of the present invention.

[0193] Referring to Figure 2a , a trench 13 can be formed in the upper film 11 on the lower film 10. As an example, an upper film 11 can be formed on the lower film 10, and a nitride film (polishing stop film) 12 can be formed on the upper film 11. The lower film 10 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.

[0194] When the upper film 11 includes a plurality of stacked insulating films, these insulating films may be of the same type or different types from each other. As an example, the upper film 11 may include a plurality of silicon oxide films and a plurality of silicon nitride films that are alternately and repeatedly stacked. The upper film 11 may 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 may be disposed below the semiconductor film.

[0195] For example, silicon nitride (e.g., SiN), polysilicon, metal nitride (e.g., TiN), metal, etc. may be deposited so that the nitride film (etch stop film) 12 has a relatively large thickness (e.g., ). The trench 13 may be formed by an etching process or a drilling process. The trench 13 may 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 trench 13 may have a depth sufficient to expose the lower film 10.

[0196] Referring to Figure 2b , in STI, an oxide film may be formed in a double structure. First, before officially filling the trench 13 that secures the space with an insulating material, 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 trench 13 by high-density plasma CVD (HDPCVD), 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) may 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 may also be used instead of the oxide film.

[0197] Referring to Figure 2c , a plurality of insulators may be deposited to form the first insulating film 14 and the 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 and patterned by high-density plasma (HDP) oxide. The first insulating film 14 may be formed in a shape that extends along the inner surface of the trench 13. For example, the first insulating film 14 may be in a U-shaped or tubular shape that opens upward.

[0198] 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 can 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.

[0199] According to another implementation example of the present invention, although not shown, a part of the second insulating film 15 can be removed so that the second insulating film 15 remains on the trench 13. For example, the second insulating film 15 can 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.

[0200] Referring to Figure 2d , a planarization process can be performed on the second insulating film 15. For example, the second insulating film 15 can be planarized by a chemical mechanical polishing (CMP) process. The chemical mechanical polishing process can be continuously performed until the nitride film (polishing stop film) 12 is exposed. The chemical mechanical polishing process can be performed after the formation of the second insulating film 15 in Figure 2b . 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.

[0201] 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 being affected by 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 required. When the nitride film is removed 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, it is not necessary 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.

[0202] According to another implementation example of the present invention, after the gap filling, the chemical mechanical polishing (CMP) process completely removes the first insulating film 14 and the second insulating film 15 on the upper part of the nitride film (polishing stop film) 12 to isolate the active area from the field area, as Figure 2f shown, the process can be roughly divided into three steps.

[0203] In the first step, bulk CMP is performed on the second insulating film 15 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, 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.

[0204] 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.

[0205] 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.

[0206] The dispersion stability of the slurry composition for chemical mechanical polishing according to an implementation example of the present invention is high. The Ce content on the surface of the cerium oxide particles contained in the slurry composition is high, and it can 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 the silicon oxide film from the surface in the CMP process of semiconductor devices. 3+ content is high, and it can 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 the silicon oxide film from the surface in the CMP process of semiconductor devices.

[0207] A third embodiment of the present invention provides a semiconductor device, which includes: a substrate; and a trench located on the substrate and filled with an insulating material, wherein the trench is formed by grinding 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 wherein the slurry composition for chemical mechanical polishing contains cerium oxide particles, a solvent, a cationic polymer, and a polysilicon polishing inhibitor.

[0208] Details of parts that are repeated with the first and second embodiments of the present invention are omitted, but the descriptions of the first and second embodiments of the present invention are equally applicable to the third embodiment.

[0209] A 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.

[0210] Details of parts that are repeated with the first to third embodiments of the present invention are omitted, but the descriptions of the first to third embodiments of the present invention are equally applicable to the fourth embodiment.

[0211] 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 produce cerium oxide particles as a product.

[0212] In one implementation example of the present invention, the following step may be included: 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. The step of pulverizing cerium oxide particles in a solution containing the raw material precursor may be performed by a pulverization process, for example, and the pulverization method may 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.

[0213] 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 above-described characteristics of the particles.

[0214] 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.

[0215] The scope of the present invention is represented 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.

[0216] Industrial Applicability

[0217] 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, 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 where no additive is added, improved effects can be obtained simultaneously, and thus it has industrial applicability. 3+ ​

Claims

1. A slurry composition for chemical mechanical polishing, characterized in that, Comprising: Cerium oxide particles; A solvent; A cationic polymer; and A polysilicon 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.

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 polysilicon film decreases as the content of the polysilicon 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 polysilicon 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 polysilicon polishing inhibitor is a cationic surfactant, a monomolecular surfactant, a substance containing a hydrophobic functional group, or a combination thereof.

8. The slurry composition for chemical mechanical polishing according to claim 1, characterized in that, The polysilicon polishing inhibitor is a monomolecular cationic surfactant, and includes at least one selected from cetylpyridinium chloride, docosyltrimethylammonium chloride, benzalkonium chloride, benzalkonium bromide, cetyl dimethyl benzyl ammonium chloride, cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, didodecyldimethylammonium chloride, distearyldimethylammonium bromide, distearyldimethylammonium chloride, and octadecyl dimethyl benzyl ammonium chloride.

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 includes a pH adjuster, and the pH adjuster 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, gum acid, glycolic acid, formic acid, lactic acid, malic acid, carotinic 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, characterized in that, 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, characterized in that, 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, characterized in that, The slurry composition for chemical mechanical polishing has a polishing selectivity of oxide film / polysilicon 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 produced by a step of obtaining a dispersion of particles by precipitation in a solution containing a raw material precursor 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 as described in claim 1.

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