JP4666138B2 - Polishing composition containing aqueous zirconia sol - Google Patents

Description

  The present invention relates to a polishing composition particularly suitable for a shallow trench isolation forming step in a substrate surface flattening step in a semiconductor device manufacturing process.

Colloidal zirconium oxide having a specific surface area of 10 to 400 m ² / g, a dynamic light scattering particle diameter of 20 to 500 nm, and containing 4 to 15% by weight of dehydrating water is 400 to 1000 A colloid before calcining with a dynamic light scattering particle size by adding a water-soluble acid or a water-soluble alkali to a calcined zirconium oxide obtained by calcining at a temperature of 0.degree. C. for 0.05 to 50 hours. An aqueous sol of zirconium oxide having a particle size of 1 to 3 times the particle size of the zirconium oxide and a method for producing the same are disclosed. (Patent Document 1)
An abrasive comprising zirconia and a polymer acid such as polyacrylic acid is disclosed. (Patent Document 2 and Patent Document 3)
JP-A-8-59242 (Claims, Examples) Japanese Patent No. 3130279 (Claims) Japanese Patent No. 3278532 (Claims)

 The aqueous sol of zirconium oxide of the present invention is, for example, ultra-precision polishing of a substrate surface flattening process, particularly a shallow trench isolation forming process, which is usually called CMP (Chemical Mechanical Polishing). To increase the polishing rate ratio between the silicon oxide film and the silicon nitride film, and to provide an abrasive with little alkali metal contamination.

The present invention as the first aspect, having a particle size in the range of 3~110nm converted from its specific surface area value of 10 to 400 m ² / g, average primary particle diameter measured by a scanning electron microscope observation 5 A polishing composition comprising an aqueous sol containing zirconium oxide particles in a range of 150 nm, and used for polishing a silicon oxide film during production of a semiconductor device;
As a second aspect, the polishing according to the first aspect, wherein the zirconium oxide particles have a volume fraction d10 measured by a laser diffraction method of 60 to 100 nm, d50 of 80 to 300 nm, and d90 of 150 to 2000 nm. Composition,
As a third aspect, the polishing composition according to the first aspect or the second aspect, wherein the aqueous sol further contains an anionic surfactant,
As a fourth aspect, a substrate having at least a silicon oxide film and a silicon nitride film is mainly polished using the polishing composition according to any one of the first to third aspects. And, as a fifth aspect, the semiconductor device according to the fourth aspect, wherein the ratio of (silicon oxide film polishing rate) / (silicon nitride film polishing rate) is 10 to 100. It is a manufacturing method.

The present invention has a specific surface area value of 10 to 400 m ² / g and a particle diameter in the range of 3 to 110 nm converted therefrom, and the average value of the primary particle diameter by scanning electron microscope observation is in the range of 5 to 150 nm. A polishing composition containing an aqueous sol containing certain zirconium oxide particles is suitable for forming shallow trench isolation (separation of Si and SiO ₂ on a substrate) in planarization polishing of a substrate surface in a semiconductor device manufacturing process. I found out.

The aqueous sol has a specific surface area of 10 to 400 m ² / g, the particle diameter converted from the specific surface area is (A) nm, and the primary particle diameter is as observed by a scanning electron microscope (SEM). When the average value is (B) nm, it contains zirconium oxide particles having a B / A value of 1 to 40.

  Further, the dispersant for the polishing composition containing the aqueous sol does not contain an alkali metal such as polyacrylic acid, polyammonium acrylate, polymethacrylic acid, polyammonium methacrylate, and polyacrylic acid-methacrylic acid copolymer. By using a water-soluble anionic surfactant, it is possible to reduce the content of alkali metal that becomes a contamination source of the wafer, and further, the polishing rate ratio of the silicon oxide film to the silicon nitride film is improved to a range of 10 to 100. The planarization characteristics in the separation process are improved. As for the average molecular weight of the anionic surfactant used as a dispersing agent, 500-50000 are preferable, More preferably, it is 1000-10000.

The present invention has a specific surface area value of 10 to 400 m ² / g and a particle diameter in the range of 3 to 110 nm converted therefrom, and the average primary particle diameter by scanning electron microscope observation is in the range of 5 to 150 nm. A polishing composition comprising an aqueous sol containing zirconium oxide particles and used for polishing a silicon oxide film during production of a semiconductor device.

  The aqueous sol containing zirconium oxide particles used in the present invention can be produced by the following method. For example, the aqueous medium which melt | dissolved the zirconium compound can be manufactured by carrying out the hydrothermal treatment for 1 to 100 hours at the temperature of 70-250 degreeC in an autoclave. Examples of the zirconium compound include zirconium nitrate, zirconium sulfate, zirconium oxychloride, and zirconium acetate, and one or more of these can be used. The aqueous medium in which the zirconium compound is dissolved is preferably hydrothermally treated by adjusting the pH to a range of 6 to 11 using ammonia water or the like. The obtained colloidal zirconium oxide is preferably washed using an ultrafiltration device. At this time, impurities can be sufficiently removed by adding an alkali or an acid and washing. Examples of the alkali used here include aqueous ammonia, and examples of the acid include hydrochloric acid, nitric acid, lactic acid, acetic acid, propionic acid, formic acid, butyric acid, methylsulfonic acid, malonic acid, maleic acid, oxalic acid, phthalic acid, and citric acid. , Malic acid, tartaric acid and the like. Impurities can be removed by washing with pure water after washing with pure water, further with acid and washing with pure water. It is preferable to perform these operations alternately several times for cleaning. The zirconium oxide sol thus obtained can be dried at a temperature of 100 to 200 ° C. with a dryer such as a spray dryer to obtain a colloidal zirconium oxide powder. This powder contains 4 to 15% by weight of water and is dehydrated in a subsequent baking step.

  The obtained powder can be fired in a firing furnace to obtain a fired zirconium oxide powder. The firing temperature is 300 to 1000 ° C., preferably 400 to 900 ° C., and the firing time is 5 to 100 hours. If the firing temperature is less than 300 ° C., the polishing rate of the silicon oxide film is slow and not preferable. On the other hand, when the temperature exceeds 1000 ° C., the primary particles of zirconium oxide become too large, which causes scratches when used as an abrasive.

  The zirconium oxide thus obtained has main peaks at diffraction angles 2θ = 28.6 °, 47.5 °, and 56.4 ° in the X-ray diffraction pattern. 34-394 monoclinic crystalline zirconium oxide particles.

  The calcined zirconium oxide powder can be wet pulverized in an aqueous medium to obtain an aqueous sol. The wet pulverization is carried out batchwise or continuously in an apparatus such as a wet ball mill, a sand grinder, an attritor, a pearl mill, an ultrasonic homogenizer, a pressure homogenizer, or an optimizer. As a material of media used for wet grinding such as a wet ball mill, a sand grinder, an attritor, and a pearl mill, for example, partially stabilized zirconia beads are used, and beads having a particle diameter of 0.1 to 10 mmφ can be used. .

  Wet pulverization is carried out by adding acids such as hydrochloric acid, nitric acid, lactic acid, acetic acid, propionic acid, formic acid, butyric acid, methyl sulfonic acid, malonic acid, maleic acid, oxalic acid, phthalic acid, citric acid, malic acid, tartaric acid to pH 1-6 Adjust to the range and crush. Moreover, an anionic surfactant and a water-soluble alkali silicate can be used as a dispersing agent for wet grinding. It is particularly preferable to use an anionic surfactant having an average molecular weight of 1000 to 10,000. The above dispersants can be used alone or in combination of two or more. These dispersants are preferably added in a proportion of 0.01 to 0.05 parts by weight with respect to 1 part by weight of zirconium oxide.

  Examples of anionic surfactants include water-soluble polymers such as ammonium salts of acrylic acid polymers and ammonium salts of methacrylic acid polymers, ammonium oleate, ammonium lauryl sulfate, triethanolamine lauryl sulfate, and polyoxyethylene lauryl. Examples include ether ammonium sulfate.

  Examples of the water-soluble alkali silicate include ammonium silicate and quaternary ammonium silicate. These are dispersants that do not contain an alkali metal. However, in applications where a polishing composition containing an alkali metal can be used, a water-soluble high salt such as a sodium salt of an acrylic acid polymer or a sodium salt of a methacrylic acid polymer. Molecules, anionic surfactants such as sodium oleate, sodium lauryl sulfate, sodium polyoxyethylene lauryl ether sulfate, and dispersants such as lithium silicate, sodium silicate, and potassium silicate can also be used.

  When a base such as aqueous ammonia, quaternary ammonium hydroxide, lithium hydroxide, sodium hydroxide, potassium hydroxide or the like is used as a dispersant instead of a water-soluble alkali silicate, the slurry aggregates when wet pulverizing zirconium oxide, It becomes easy to thicken.

  The solid content concentration of the aqueous sol when the zirconium oxide powder is wet-pulverized and dispersed in the present invention is preferably 10 to 70% by weight, more preferably 30 to 60% by weight. If the solid content concentration is lower than 10% by weight, the pulverization efficiency is deteriorated. On the other hand, when the solid content is higher than 70% by weight, the aqueous sol is thickened, so that the pulverization and dispersion efficiency deteriorates.

The aqueous sol containing zirconium oxide particles obtained by the present invention has a particle diameter of 10 to 300 nm as observed with a transmission electron microscope (TEM). Further, even after the calcined zirconium oxide particles were wet-pulverized to form an aqueous sol, the aqueous sol was dried at 110 ° C. and the X-ray diffraction pattern was measured. As a result, the diffraction angle 2θ = 28.6 °, 47.5 It has main peaks at ° and 56.4 °, and has ASTM card no. 34-394 monoclinic crystalline zirconium oxide particles. The specific surface area value of the zirconium oxide particles is 10 to 400 m ² / g. When the particle diameter is (D) nm and the specific surface area is (P) m ² / g, the relational expression D × P = 1100 is established. According to this formula, the specific surface area value was measured by the gas adsorption method (BET method) of zirconium oxide particles, and the particle diameter converted as spherical particles (BET method converted particle diameter) is 3 to 110 nm. Moreover, the d10 particle diameter of zirconium oxide by a laser diffraction method is 60 to 100 nm, the d50 particle diameter is 80 to 300 nm, and the d90 particle diameter is 150 to 2000 nm.

  Here, d10 represents a particle size which means that the number of particles equal to or smaller than this particle size is 10% of the total number of particles.

  d50 represents a particle size which means that the number of particles equal to or smaller than this particle size is 50% of the total number of particles.

  d90 represents a particle size which means that the number of particles equal to or smaller than this particle size is 90% of the total number of particles.

  In particular, an aqueous sol containing zirconium oxide particles having a d50 particle diameter of 80 to 180 nm in the laser diffraction method and a d90 particle diameter of 1000 nm or less in the laser diffraction method is close to monodisperse particles, so that the particles settle even when left for a long time. It is easy to return to the dispersed state at the time of manufacture by light agitation or shaking, and is stable for more than 1 year even when stored at room temperature.

  The aqueous sol containing the zirconium oxide particles of the present invention can be used as it is as a polishing composition. However, it contains an anionic surfactant, a water-soluble alkali silicate, and a nonionic surfactant as a dispersant in the aqueous sol, so that a more preferable polishing composition can be obtained. The above dispersant is used alone. It can also be used in combinations of two or more. In addition, the same kind of additives having different average molecular weights can be used in combination. As the anionic surfactant and the water-soluble alkali silicate, the dispersant used in the wet pulverization can be used. Examples of the nonionic surfactant include phosphorus-containing surfactants such as phosphoric acid monoalkyl ester, phosphoric acid dialkyl ester, and phosphoric acid trialkyl ester. When preparing a polishing composition by adding a dispersant to an aqueous sol, the above dispersant is 0 to 3 parts by weight, preferably 0.01 to 1.5 parts by weight per 1 part by weight of zirconium oxide. It is preferable to add.

  A polishing composition obtained by adding an anionic surfactant to an aqueous sol of zirconium oxide, when the molecular weight of the anionic surfactant is low, when polishing a substrate having a silicon oxide film and a silicon nitride film, The ratio of (polishing rate of silicon oxide film) / (polishing rate of silicon nitride film) tends to increase.

When used as a polishing composition containing an aqueous sol of zirconium oxide particles of the present invention, for example, problems of sedimentation and consolidation in piping from the polishing composition supply source to the polishing machine, and use them for a long time Since the problem of sedimentation and consolidation does not occur, the polishing composition can always be supplied with a constant quality, and a constant polishing performance can always be exhibited. This polishing composition is suitable for the formation of shallow trench isolation (separation of Si and SiO ₂ on the substrate) among the planarization polishing of the substrate surface in the semiconductor device manufacturing process, and the polishing rate of the silicon oxide film and the silicon nitride A good polished surface with few scratches can be obtained while maintaining a high selectivity of the film polishing rate.

Example 1
An aqueous solution of zirconium oxychloride in which 1000 kg of zirconium oxychloride is dissolved in 2100 kg of pure water is charged into a 4 m ³ glass-lined autoclave reaction vessel, and 264 kg of 25% ammonia water is added with stirring. After the addition, the temperature is raised to 130 ° C. and held for 7 hours. The liquid in the autoclave is then cooled to room temperature and collected. The collected liquid is an aqueous sol of colloidal zirconia having a pH of 1 or less and an average primary particle diameter of 100 nm observed with a transmission electron microscope. After adding 11.7 kg of 25% ammonia water to the recovered sol, washing is performed using 28000 kg of pure water in an ultrafiltration device. Further, 31 kg of citric acid and then 39 kg of 25% aqueous ammonia are added with stirring, and then pure water is washed with an ultrafiltration device. By using 7800 kg of pure water, alkaline zirconium oxide sol (S-1) having a pH of 10.0, a ZrO ₂ concentration of 30.4% by weight, a Cl concentration of 0.01% by weight or less, and an NH ₃ concentration of 0.32% by weight. ) 1000kg is obtained.

200 kg of this weakly alkaline zirconium oxide sol (S-1) was dried with a spray dryer having an inlet temperature of 190 ° C. and an outlet temperature of 120 ° C. to obtain 60 kg of powder. The specific surface area of this time dry powder was 153.0m ² / g. 3600 g of the obtained dry powder was placed in an electric furnace and baked at 500 ° C. for 5 hours. The obtained fired powder was measured by a powder X-ray diffraction method. This coincided with the characteristic peak of monoclinic crystalline zirconium oxide described in 34-394. The specific surface area of the zirconium oxide particles by gas adsorption method (BET method) was 45.8 m ² / g, and the particle diameter converted from the specific surface area by gas adsorption method was 24 nm.

A slurry is prepared by adding 369 g of calcined zirconium oxide powder obtained in an aqueous solution in which 3.3 g of 10% nitric acid and 745.8 g of pure water are mixed. It put into the container and wet-pulverized for 12 hours at 60 rpm. Water separation (b-1) having a solid content of 22.3% by weight, a pH of 5.8, an electric conductivity of 53 μS / cm, and a viscosity of 156 mPa · s was obtained by water separation. The specific surface area value of zirconium oxide particles obtained by drying this aqueous sol at 300 ° C. by gas adsorption method (BET method) is 52.0 m ² / g, and the particle diameter converted from the specific surface area by gas adsorption method is 21 nm. Met. In addition, the average value of primary particles by SEM observation is 110 nm, and the average particle size by scanning electron microscope observation (average value of SEM particle size) / particle size converted from specific surface area value by gas adsorption method The value of (BET particle diameter) was 5.2. Furthermore, the d10 particle diameter of the laser diffraction method measured by MASTERSIZER 2000 (manufactured by MARVERN) was 65 nm, the d50 particle diameter was 113 nm, and the d90 particle diameter was 206 nm. Moreover, the average particle diameter of the dynamic light scattering method measured by DLS-6000 (made by Otsuka Electronics) was 164 nm. The aqueous sol had almost no sediment even after standing for a long time.

Example 2
1 mmφ zirconia beads were prepared by mixing 369 g of the zirconium oxide fired powder obtained in Example 1, 21.0 g of 35 wt.% Ammonium polyacrylate solution (average molecular weight of polyacrylic acid 1500) and 728.1 g of pure water. 3800 g was charged in a 3 liter ball mill container and wet pulverized for 12 hours at 60 rpm. An aqueous sol (b-2) having a solid content of 23.7% by weight, a pH of 9.5, an electric conductivity of 1849 μS / cm, and a viscosity of 1.5 mPa · s was obtained by water separation. Specific surface area according to this aqueous sol of dry gas adsorption method of the obtained zirconium oxide particles at 400 ° C. (BET method) is 52.0m 2 / ^g, 21nm as the particle size converted from the specific surface area by gas adsorption method Met. In addition, the average value of primary particles by SEM observation is 110 nm, and the average particle size by scanning electron microscope observation (average value of SEM particle size) / particle size converted from specific surface area value by gas adsorption method The value of (BET particle diameter) was 5.2. Furthermore, the d10 particle diameter of the laser diffraction method measured by MASTERSIZER 2000 (manufactured by MARVERN) was 67 nm, the d50 particle diameter was 105 nm, and the d90 particle diameter was 166 nm. The average particle size of the dynamic light scattering method was 127 nm. The aqueous sol had almost no sediment even after standing for a long time.

Example 3
3600 g of the dried zirconium oxide powder obtained in Example 1 was placed in an electric furnace and fired at 400 ° C. for 10 hours. The obtained fired powder was measured by a powder X-ray diffraction method. This coincided with the characteristic peak of monoclinic crystalline zirconium oxide described in 34-394. Moreover, the specific surface area value by the gas adsorption method (BET method) of zirconium oxide particles was 96.0 m ² / g, and the particle diameter converted from the specific surface area by the gas adsorption method was 11 nm.
1 mmφ zirconia beads were prepared by adding 369 g of zirconium oxide fired powder obtained in an aqueous solution obtained by mixing 21.0 g of 35 wt% ammonium polyacrylate solution (average molecular weight of polyacrylic acid 1500) and 728.1 g of pure water. 3800 g was charged in a 3 liter ball mill container and wet pulverized for 12 hours at 60 rpm. An aqueous sol (b-3) having a solid content of 23.6% by weight, a pH of 9.9, an electric conductivity of 822 μS / cm, and a viscosity of 2.8 mPa · s was obtained by water separation. The specific surface area of the zirconium oxide particles obtained by drying this aqueous sol at 400 ° C. by gas adsorption method (BET method) is 95.0 m ² / g, and the particle diameter converted from the specific surface area by gas adsorption method is 11 nm. Met. In addition, the average value of primary particles by SEM observation is 110 nm, and the average particle size by scanning electron microscope observation (average value of SEM particle size) / particle size converted from specific surface area value by gas adsorption method The value of (BET particle diameter) was 10.0. Furthermore, the d10 particle diameter of the laser diffraction method measured by MASTERSIZER 2000 (manufactured by MARVERN) was 69 nm, the d50 particle diameter was 161 nm, and the d90 particle diameter was 1757 nm. The average particle size of the dynamic light scattering method was 211 nm. The aqueous sol had almost no sediment even after standing for a long time.
Comparative Example 1
A commercially available fumed silica slurry (manufactured by CABOT) having a silicon oxide concentration of 25% by weight was diluted with pure water to a silicon oxide concentration of 12.8% by weight to prepare a polishing composition (c-1). The d10 particle diameter of the laser diffraction method measured by MASTERSIZER 2000 (manufactured by MARVERN) was 81 nm, the d50 particle diameter was 126 nm, the d90 particle diameter was 191 nm, and the average particle diameter of the dynamic light scattering method was 168 nm.

After adding 50% by weight of 40 wt% ammonium polyacrylate (average molecular weight of polyacrylic acid 8000) to zirconium oxide in the aqueous sol (b-1) of Example 1, the solid content of zirconium oxide was 2 wt%. The polishing composition (a-1) was prepared by diluting with pure water so that the concentration was 1%.
After adding 40 wt% ammonium polyacrylate (average molecular weight of polyacrylic acid 8000) to 50 wt% of zirconium oxide to the aqueous sol (b-2) of Example 2, the solid content of zirconium oxide was 2 wt%. The composition for polishing (a-2) was prepared by diluting with pure water so that the concentration was%.
After adding 40 wt% ammonium polyacrylate (average molecular weight of polyacrylic acid 8000) to 50 wt% of zirconium oxide to the aqueous sol (b-3) of Example 3, the solid content of zirconium oxide was 2 wt%. The polishing composition (a-3) was prepared by diluting with pure water so that the concentration was%.
After adding 50% by weight of ammonium polyacrylate (average molecular weight of polyacrylic acid 8000) of 40% by weight to silica in the aqueous sol (c-1) of Comparative Example 1, the solid content of silicon oxide is 2% by weight. A polishing composition (c-2) was prepared by diluting with pure water so that

  Polishing of the prepared polishing composition was performed as follows.

Polishing machine (Technorise Co., Ltd.),
Abrasive cloth: Polished cloth IC-1000 / suba400 (made by Rodel Nitta Co., Ltd.)
Object to be polished: silicon wafer having plasma CVD silicon oxide film and CVD silicon nitride film Rotation speed: 150 rpm,
Polishing pressure: 333 g / cm ²
Polishing time: 2 minutes.

In Table 1, the evaluation of the polished surface was performed by visual inspection, and when a defect was observed, a (x) mark was described, and when there was no defect, a (◯) mark was described. The polishing rate of the silicon oxide film and the silicon nitride film was determined by measuring the film thickness before and after polishing with a film thickness meter NANOSPEC (manufactured by NANOMETORICS) and calculating the polishing rate. Further, the ratio of the polishing rates of the silicon oxide film and the silicon nitride film was obtained.
[Table 1]
Table 1
――――――――――――――――――――――――――――――――――
Polishing composition Silicon oxide film Silicon nitride film Silicon oxide / silicon nitride Surface defects
Polishing rate ratio of polishing rate to polishing rate
(Å / min) (Å / min)
――――――――――――――――――――――――――――――――――
(A-1) 769 41 19 ○
(A-2) 892 65 14 ○
(A-3) 926 71 13 ○
(C-1) 2279 385 6 ○
(C-2) 133 60 2 ○
――――――――――――――――――――――――――――――――――
In the polishing compositions of Examples 1 to 3 (a-1, a-2, and a-3), the polishing rate of the silicon oxide film was increased with respect to the polishing composition (c-2) of Comparative Example 1, Since the polishing rate of the silicon nitride film is equal, the polishing rate ratio of silicon oxide / silicon nitride is improved. In addition, as a result of the decrease in the polishing rate of the silicon nitride film with respect to the polishing composition (c-1) of Comparative Example 1, the polishing rate ratio of silicon oxide / silicon nitride is improved. For this reason, it turns out that the polishing composition of this invention can be planarized efficiently in shallow trench isolation | separation.

  The polishing composition of the present invention is suitable as an abrasive used for planarization polishing in a semiconductor device manufacturing process, which is generally called CMP (Chemical Mechanical Polishing). In particular, since the silicon nitride film used as the protective film can be precisely polished without damaging it, the polishing used for the element isolation process of a semiconductor device generally called STI (Shallow Trench Isolation). Suitable as an agent. Further, it is also suitable as an abrasive used for polishing a low dielectric constant material for an interlayer insulating film of a semiconductor device such as a siloxane, organic polymer, porous material or CVD polymer. Examples of siloxane-based materials include hydrogenated silsesquioxane, methyl silsesquioxane, and hydrogenated methyl silsesquioxane. Examples of organic polymer materials include polyarylene ethers, thermally polymerizable hydrocarbons, perfluorohydrocarbons, polyquinolines, and fluorinated polyimides. Examples of the porous material-based material include xerogel and silica colloid. Examples of CVD polymer-based materials include diamond-like carbon films, fluorocarbons, aromatic hydrocarbon polymers, and siloxane-based polymers.

  Here, the substrate mainly composed of silica refers to, for example, quartz, quartz glass, a glass hard disk, an organic film of a semiconductor device, a low dielectric constant film, an interlayer insulating film, and trench isolation CMP. Further, the aqueous zirconium oxide sol of the present invention is an optical crystal material such as lithium niobate and lithium tantalate, a ceramic material such as aluminum nitride, alumina, ferrite and zirconia, and polishing of metal wiring such as aluminum, copper and tungsten of semiconductor devices. It can also be applied to.

Claims (4)

10 to 400 m ² / g have a particle size in the range of 3~110nm to be converted specific surface area and then the average value of primary particle diameter measured by a scanning electron microscope observation Ri range near the 5 to 150 nm, and An aqueous sol containing zirconium oxide particles having a volume fraction d10 measured by a laser diffraction method of 60 to 100 nm, d50 of 80 to 300 nm, and d90 of 150 to 2000 nm is oxidized during the manufacture of a semiconductor device. A polishing composition used for polishing a silicon film. The polishing composition according to claim 1 , wherein the aqueous sol further comprises an anionic surfactant. A method for manufacturing a semiconductor device, comprising: a step of mainly polishing a silicon oxide film on a substrate having at least a silicon oxide film and a silicon nitride film using the polishing composition according to claim 1 . The method of manufacturing a semiconductor device according to claim 3 , wherein a ratio of (polishing rate of silicon oxide film) / (polishing rate of silicon nitride film) is 10 to 100. 5.