JP5248096B2 - Polishing liquid composition - Google Patents

Description

  The present invention relates to a polishing liquid composition used in chemical mechanical polishing (CMP) performed in a manufacturing process of a semiconductor device or the like, or a polishing process performed in a manufacturing process of a precision glass product or a display related product. . The present invention also relates to a polishing method using the above polishing composition, a method for manufacturing a glass substrate, and a method for manufacturing a semiconductor device.

  Crystallization of an oxide film (for example, silicon oxide film) constituting a semiconductor device, a base material of a glass substrate as exemplified below, that is, a base material of a chemically strengthened glass substrate such as an aluminosilicate glass substrate, or a glass ceramic substrate For example, composite oxide particles containing cerium and zirconium are used for polishing a substrate of a glass substrate, a substrate of a synthetic quartz glass substrate used as a substrate for a photomask, or a glass surface of a liquid crystal display panel ( For example, see Patent Documents 1 and 2).

In order to solve the problem of generation of scratches and dust that occurs when the polishing composition described in Patent Document 1 is polished using an abrasive composition containing cerium oxide particles as an abrasive, Instead of the cerium oxide particles, composite oxide particles whose secondary particles have an average particle diameter of 5 μm or less are included as an abrasive. The oxidation number of cerium in the cerium compound (for example, CeCl ₃ ) that is a raw material of the composite oxide particles is 3, and the oxidation number of zirconia in the zirconia compound (ZrOCl ₂ ) is 4. The composite oxide particles are prepared as follows.

  A cerium compound and a zirconium compound are reacted with ammonia in an aqueous solution to form a water-insoluble compound containing cerium and zirconium, and then a coprecipitate is obtained through oxidation treatment, filtration, and centrifugation. The coprecipitate is repeatedly washed with ultrapure water or the like, dried, and then heat-treated in an oven having an atmospheric temperature of 300 ° C. or higher, whereby composite oxide particles are obtained.

On the other hand, the polishing composition described in Patent Document 2 contains composite oxide particles produced without going through a firing step. Patent Document 2 discloses that this polishing composition can form a surface with high surface accuracy, has a high polishing rate despite the small particle size of the composite oxide particles, and suppresses the occurrence of damage such as scratches. It is stated that it can be done. The oxidation number of cerium in the cerium compound that is the raw material of the composite oxide particles is 3 or 4, and the oxidation number of zirconium in the zirconium compound is 4.
JP 2001-348563 A Japanese Patent No. 3782771

  However, in polishing using these polishing liquid compositions, a sufficient polishing rate cannot be ensured, and scratches cannot be reduced.

  In the present invention, there are provided a polishing composition capable of polishing an object to be polished at a higher speed, a polishing method using the same, a method for manufacturing a glass substrate, and a method for manufacturing a semiconductor device.

The polishing liquid composition of the present invention is a polishing liquid composition containing composite oxide particles containing cerium and zirconium, a dispersant, and an aqueous medium, and is irradiated with CuKα1 rays (λ = 0.154050 nm). In the powder X-ray diffraction spectrum of the composite oxide particles obtained by this, a peak (first peak) having a peak within a diffraction angle 2θ (θ is a black angle) region of 28.61 to 29.67 ° (first peak), a diffraction angle 2θ region 33.14 to 34.53 ° peak (second peak), diffraction angle 2θ region 47.57 to 49.63 ° peak (third peak), diffraction angle 2θ region Each peak has a peak (fourth peak) within 56.5 to 58.91 °, and the half-width of the first peak is 0.8 ° or less. In the powder X-ray diffraction spectrum, peak a ₁ derived from cerium oxide, If at least one peak of the peak a ₂ derived from the zirconium is present, the height of the apex of the peak a _1, a ₂ is less than 6.0% of the apex height of the first peak . However, the apex of the peak a ₁ exists in a diffraction angle 2θ region of 28.40 to 28.59 °, and the apex of the peak a ₂ exists in a diffraction angle 2θ region of 29.69 to 31.60 °.

  The polishing composition of the present invention is a polishing composition containing composite oxide particles containing cerium and zirconium, a dispersant, and an aqueous medium, wherein the composite oxide particles have an oxidation number. The cerium compound and the zirconium compound are hydrolyzed by mixing a solution containing a cerium compound of 4 and a zirconium compound having an oxidation number of 4 with a precipitant, and the resulting precipitate is separated. Composite oxide particles obtained by firing and pulverizing the obtained fired product.

  In the polishing method of the present invention, the polishing liquid composition of the present invention is supplied between a polishing object and a polishing pad, and the polishing pad is polished while the polishing object and the polishing pad are in contact with each other. A step of polishing the polishing object by moving the object relative to the object;

  The manufacturing method of the glass substrate of this invention includes the grinding | polishing process which grind | polishes at least one main surface of the both main surfaces of the base material of a glass substrate using the polishing liquid composition of this invention.

  The method for manufacturing a semiconductor device of the present invention includes a thin film forming step in which one main surface on a semiconductor substrate forms a thin film and a polishing step in which the thin film is polished with the polishing composition of the present invention. .

  ADVANTAGE OF THE INVENTION According to this invention, the polishing liquid composition which can grind | polish a grinding | polishing target object at higher speed, the grinding | polishing method using the same, the manufacturing method of a glass substrate, and the manufacturing method of a semiconductor device can be provided.

The composite oxide particles are represented by the following composition formula, for example.
Ce _x Zr _1-x O ₂
However, x is a conditional expression 0 <x <1, preferably 0.50 <x <0.97, more preferably 0.55 <x <0.95, and still more preferably 0.60 <x <0.90. Even more preferably, the number satisfies 0.65x <0.90, and even more preferably 0.70x <0.90.

  In the composite oxide particles, cerium oxide and zirconium oxide are uniformly dissolved to form one solid phase, and this composite oxide particle is X-ray (Cu-Kα1 line, λ = 0.154050 nm). ) The following peaks are observed in the spectrum obtained by analyzing by the diffraction method.

  That is, in the spectrum, at least a peak having a peak within a diffraction angle 2θ region of 28.61 to 29.67 ° (first peak) and a peak having a peak within a diffraction angle 2θ region of 33.14 to 34.53 °. (Second peak), peak having a peak in the diffraction angle 2θ region 47.57 to 49.63 ° (third peak), and peak having a peak in the diffraction angle 2θ region 56.45 to 58.91 ° (4th peak) is observed.

  From the viewpoint of improving the polishing rate, the composite oxide particles have a peak (first peak) having a peak within at least a diffraction angle 2θ region of 28.61 to 29.39 ° in the spectrum, and a diffraction angle 2θ region of 33.14. Peak having a vertex within ˜34.16 ° (second peak), peak having a vertex within diffraction angle 2θ region 47.57 to 49.08 ° (third peak), and diffraction angle 2θ region 56.45 It is preferable that a peak (fourth peak) having a vertex within ˜58.25 ° is observed, and further, a peak having a vertex within the diffraction angle 2θ region of 28.61 to 29.25 ° (first peak). Peak), peak with a peak in the diffraction angle 2θ region 33.14 to 34.04 ° (second peak), peak with a peak in the diffraction angle 2θ region 47.57 to 48.90 ° (third peak) , And diffraction angle 2θ region 56.45- More preferably, a peak having a vertex within the 8.02 ° (fourth peak) is observed, and further, a peak having a vertex within the diffraction angle 2θ region of 28.68 to 29.11 ° (the fourth peak). 1 peak), a peak with a peak in the diffraction angle 2θ region 33.23 to 33.79 (second peak), a peak with a peak in the diffraction angle 2θ region 47.71 to 48.53 ° (third peak) It is even more preferable that a peak (fourth peak) having an apex within the diffraction angle 2θ region of 56.61 to 57.60 ° is observed.

  The area of the second peak is 10 to 50% of the area of the first peak, the area of the third peak is 35 to 75% of the area of the first peak, and the area of the fourth peak is 20 of the area of the first peak. It is preferable that it is -65%. From the viewpoint of improving the polishing rate, the area of the second peak is 15 to 45% of the area of the first peak, the area of the third peak is 40 to 70% of the area of the first peak, and the area of the fourth peak is More preferably, it is 25-60% of the area of the first peak, the area of the second peak is 20-40% of the area of the first peak, and the area of the third peak is 45-45 of the area of the first peak. The area of 65% and the fourth peak is more preferably 30 to 55% of the area of the first peak.

There may be a case where at least one of the peak a ₁ derived from cerium oxide and the peak a ₂ derived from zirconium oxide exists in the spectrum. In this case, the peak heights of the peaks a ₁ and a ₂ are both 6.0% or less of the height of the peak of the first peak, preferably 3.0% or less, more preferably from the viewpoint of scratch reduction. Is 1.0% or less, more preferably 0%.

The diffraction angle 2θ region where the apex of the peak a ₁ exists is 28.40 ° to 28.59 °, and the diffraction angle 2θ region where the apex of the peak a ₂ exists is 29.69 ° to 31.60 °. These values for the 2θ region are based on values for cerium oxide and zirconium oxide in the international diffraction data ICDD (International Center for Diffraction Data). Specifically, the diffraction angle 2θ region 28.40 to 28.59 ° where the peak of peak a ₁ exists is a value for cubic cerium oxide. The 2θ region 29.69 to 31.60 ° where the peak of peak a ₂ is present is 2θ (29.69 °) of tetragonal zirconium oxide and 2θ (31.60 °) of monoclinic zirconium oxide. ).

From the viewpoint of improving the polishing rate, the peak a ₁ has a peak within the diffraction angle 2θ region of 28.45 ° to 28.59 °, and the peak a ₂ has a peak within the diffraction angle 2θ region of 29.70 ° to 31.55 °. Preferably, the peak a _{1 has} an apex within the diffraction angle 2θ region of 28.50 ° to 28.58 °, and the peak a _{2 has} an apex within the diffraction angle 2θ region of 29.71 ° to 31.50 °. More preferred.

  The half width of the first peak is 0.8 ° or less, but from the viewpoint of improving the polishing rate, 0.7 ° or less is preferable, 0.6 ° or less is more preferable, 0.5 ° or less is more preferable, 0.45 ° or less is even more preferable. This half-value width correlates with the crystallite size as shown in the Scherrer equation. The full width at half maximum decreases as the crystallite size increases due to crystal growth.

In the composite oxide particles of the present embodiment, as described later, cerium oxide is derived from a cerium compound having an oxidation number of 4, and zirconium oxide is derived from a zirconium compound having an oxidation number of 4, It is considered that one solid phase in which cerium oxide and zirconium oxide are uniformly dissolved is formed, and the X-ray diffraction spectrum is observed. When the cerium oxide in the composite oxide particles is derived from a cerium compound having an oxidation number of 3, like the composite oxide particles contained in the polishing liquid composition described in Patent Document 1, cerium oxide and zirconium oxide are Formation of one solid phase that is uniformly dissolved is not sufficiently performed, and at least one of a peak a ₁ derived from cerium oxide and a peak a ₂ derived from zirconium oxide is observed.

  In addition, in the X-ray diffraction spectrum of the composite oxide particles contained in the polishing liquid composition of the present embodiment, the first peak has a small half width and the first peak is very sharp. As will be described later, this is considered to be because the crystallite size of the solid phase is increased, that is, the crystallinity is improved by performing sufficient firing in the manufacturing process. Since the composite oxide particles contained in the polishing composition described in Patent Document 2 have not undergone sufficient firing during the production process, the crystallinity of the solid phase is not sufficient. The half width of the first peak in the X-ray diffraction spectrum is large and the first peak is broad.

  As described above, the polishing liquid composition of this embodiment has one solid phase in which cerium oxide and zirconium oxide are uniformly dissolved, and includes complex oxide particles having high crystallinity. It is considered that the object to be polished can be polished at a higher speed than the polishing liquid composition.

  The atomic ratio (Ce / Zr) in the composite oxide particles is preferably (99/1) to (5/95) from the viewpoint of improving the polishing rate, and (97/3) to (16 / 84), more preferably (95/5) to (40/60), even more preferably (94/6) to (50/50), and (93/7) to (60/40) is even more preferable.

In the composite oxide _{(Ce x Zr 1-x O} 2) particles, the atomic ratio x of Ce is for Zr, from the viewpoint of reducing scratches, preferably 0.60 to 0.93, more preferably 0.65 to 0 .90, more preferably 0.70 to 0.90.

  From the viewpoint of improving the polishing rate, the volume median diameter (D50) of the composite oxide particles is preferably 30 nm or more, more preferably 40 nm or more, and still more preferably 50 nm or more. Further, D50 is preferably 1000 nm or less, more preferably 500 nm or less, and still more preferably 250 nm or less, from the viewpoint of improving the dispersion stability of the composite oxide particles in the polishing composition. Therefore, the volume median diameter (D50) of the composite oxide particles is preferably 30 to 1000 nm, more preferably 40 to 500 nm, and still more preferably 50 to 250 nm.

  Here, the volume median diameter (D50) means a particle diameter at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle diameter. The volume median diameter (D50) is obtained as a volume-based median diameter measured with a laser diffraction / scattering particle size distribution meter (trade name LA-920, manufactured by Horiba, Ltd.).

  From the viewpoint of improving the polishing rate, the average primary particle diameter of the composite oxide particles is preferably 10 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. In addition, the average primary particle diameter of the composite oxide particles is preferably 200 nm or less, more preferably 150 nm or less, and still more preferably 100 nm or less, from the viewpoint of improving the mirror state of the polishing surface obtained by polishing the polishing object. It is. Therefore, the average primary particle diameter of the composite oxide particles is preferably 10 to 200 nm, more preferably 20 to 150 nm, and still more preferably 30 to 100 nm.

Here, the average primary particle size (nm) means the particle size (true sphere conversion) calculated by the following formula using the specific surface area S (m ² / g) calculated by the BET (nitrogen adsorption) method. .
Average primary particle diameter (nm) = 820 / S

  From the viewpoint of improving the polishing rate, the content of the composite oxide particles in the polishing composition is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and further preferably 0.4% by weight. Or more, and more preferably 0.5% by weight or more. Further, the content of the composite oxide particles is preferably 8% by weight or less, more preferably 5% by weight or less, and further preferably 4% by weight or less, from the viewpoint of improving dispersion stability and reducing the cost. More preferably 3% by weight or less. Accordingly, the content of the composite oxide particles is preferably 0.1 to 8% by weight, more preferably 0.2 to 5% by weight, still more preferably 0.4 to 4% by weight, and still more preferably 0.5. ~ 3 wt%.

  The composite oxide particles may be commercially available products or may be prepared in-house. Next, an example of a method for producing composite oxide particles will be described.

  The composite oxide particles include a solution containing a cerium compound having an oxidation number of 4 (hereinafter also referred to as a cerium (IV) compound) and a zirconium compound having an oxidation number of 4 (hereinafter also referred to as a zirconium (IV) compound). By mixing the precipitant, the cerium (IV) compound and the zirconium (IV) compound are hydrolyzed, the resulting precipitate is separated, then calcined, and the resulting calcined product is pulverized Can be obtained.

  The solution containing a cerium (IV) compound and a zirconium (IV) compound is prepared by, for example, dissolving a water-soluble cerium (IV) compound such as cerium nitrate and a water-soluble zirconium (IV) compound such as zirconium nitrate. It may be prepared by mixing in a solvent such as.

  If a precipitant (base solution) is added to the solution containing the cerium (IV) compound and the zirconium (IV) compound, the cerium (IV) compound and the zirconium (IV) compound are hydrolyzed, and the precipitate is formed. Generated. It is preferable to add a precipitant while stirring a solution containing a cerium (IV) compound and a zirconium (IV) compound. As the precipitating agent, ammonia solution; alkaline hydroxide solution such as sodium hydroxide solution or potassium hydroxide solution; carbonate solution of sodium, potassium or ammonia; bicarbonate solution or the like is used. The precipitant is preferably an aqueous solution of ammonia, sodium hydroxide or potassium hydroxide, more preferably an aqueous ammonia solution. The normality of the precipitating agent is preferably about 1 to 5N, and more preferably about 2 to 3N.

  The pH of the supernatant obtained by adding a precipitant to a solution containing a cerium (IV) compound and a zirconium (IV) compound is a complex oxide particle in which cerium oxide and zirconium oxide are in a highly solid solution state. From the viewpoint of obtaining the above, 7 to 11 is preferable, and 7.5 to 9.5 is more preferable.

  The mixing time of the solution containing the cerium (IV) compound and the zirconium (IV) compound and the precipitating agent is not particularly limited, but is preferably 15 minutes or more, and more preferably 30 minutes or more. The reaction between the solution containing the cerium (IV) compound and the zirconium (IV) compound and the precipitating agent can be performed at any suitable temperature such as room temperature. The precipitate produced by mixing a solution containing a cerium (IV) compound and a zirconium (IV) compound and a precipitating agent is subjected to normal solid / liquid separation such as decantation, drying, filtration and / or centrifugation. Separable from mother liquor by technology. The resulting precipitate is then washed with water or the like.

  The cerium (IV) compound in the solution is preferably simply contained in a state where the cerium (IV) compound is added to the aqueous medium, but the cerium compound containing cerium having an oxidation number of 3 is electrolyzed in the aqueous medium. By oxidation, trivalent cerium may be converted to tetravalent cerium. The cerium (IV) compound is preferably contained in an amount of 85% by weight or more, more preferably 87% by weight or more, further preferably 90% by weight or more, and 95% by weight in the total amount of the cerium compound. Even more preferably, it is contained.

  Specific examples of the cerium (IV) compound include water-soluble salts such as cerium sulfate (IV), tetraammonium cerium sulfate (IV), and diammonium cerium nitrate (IV). The cerium salt having an oxidation number of 4 is more easily hydrolyzed than the cerium salt having an oxidation number of 3, and from the viewpoint of hydrolysis rate, a zirconium (IV) compound (for example, This is because it is suitable for simultaneous hydrolysis with a zirconium salt having an oxidation number of 4).

  Zirconium (IV) compounds contained in the solution include zirconium oxychloride (zirconyl chloride), zirconium oxysulfate (zirconyl sulfate), zirconium oxyacetate (zirconyl acetate), zirconium oxynitrate (zirconyl nitrate), zirconium chloride, zirconium nitrate Water-soluble zirconium (IV) salts such as zirconium acetate and zirconium sulfate.

  As described above, when the oxidation number of cerium and zirconium in the solution is 4 and the pH of the solution is increased by adding the base solution as a precipitant to the solution, the cerium (IV) compound and zirconium (IV ) The compound is hydrolyzed in approximately the same pH region, and cerium hydroxide and zirconium hydroxide precipitate almost simultaneously, resulting in a highly mixed precipitate with each other. By heat-treating this precipitate, a portion in which cerium oxide and zirconium oxide are uniformly dissolved to form one solid phase is generated in the precipitate. If the oxidation number of cerium is 3, the pH range in which the cerium (III) compound and the zirconium (IV) compound are hydrolyzed and the hydroxide precipitates is different, so that a precipitate in which the mixing state of both is insufficient is obtained. It is done. When this precipitate is heat-treated, a portion where cerium oxide or zirconium oxide is separated is generated.

  When the total amount of oxide equivalent of cerium element and zirconium element equivalent contained in the solution containing the cerium (IV) compound and zirconium (IV) compound is 100% by weight, the oxide equivalent amount of cerium element Is preferably 7 to 99% by weight, more preferably 20 to 98% by weight, and still more preferably 50 to 96% by weight. The oxide equivalent amount of zirconium element is preferably 1 to 93% by weight, more preferably 2 to 80% by weight, and further preferably 4 to 50% by weight.

  The firing temperature of the precipitate is preferably 900 to 1500 ° C., more preferably 1000 to 1400, from the viewpoint of improving the crystallinity of the solid phase in which cerium oxide and zirconium oxide are uniformly dissolved and ensuring a good polishing rate. It is 1 degreeC, More preferably, it is 1100-1300 degreeC. The heating time is usually preferably 1 to 10 hours, more preferably 2 to 8 hours, and further preferably 3 to 7 hours. Firing can be performed using a heating means such as a continuous firing furnace. The firing temperature is the temperature of the particle surface and is equal to the ambient temperature in the continuous firing furnace.

  The means for pulverizing the fired product is not particularly limited, and examples thereof include pulverizers such as a ball mill, a bead mill, and a vibration mill. The setting conditions of the pulverizing means may be appropriately set in order to form particles having a desired average particle size range or particles having a desired volume particle size range. Examples of the grinding media include zirconia balls.

  Examples of the aqueous medium contained in the polishing liquid composition of the present embodiment include water, a mixed medium of water and a solvent, and the solvent includes a solvent that can be mixed with water (for example, alcohol such as ethanol). Is preferred. Among these, water is preferable as the aqueous medium, and ion-exchanged water is more preferable.

  The dispersant contained in the polishing composition of this embodiment is preferably water-soluble. The water-soluble dispersant is preferably at least one selected from the group consisting of a cationic surfactant, an anionic surfactant, a nonionic surfactant, and an acrylic acid polymer. More preferably, the dispersant is at least one selected from the group consisting of an anionic surfactant, a nonionic surfactant, and an acrylic acid polymer. The dispersant is more preferably an acrylic acid polymer. The dispersant may be physically adsorbed on the surface of the composite oxide particle before being mixed with the aqueous medium, or may be chemically bonded to the surface of the composite oxide particle.

  Examples of the cationic surfactant include aliphatic amine salts and aliphatic ammonium salts.

  Examples of the anionic surfactant include fatty acid soaps, carboxylates such as alkyl ether carboxylates, sulfonates such as alkylbenzene sulfonates and alkylnaphthalene sulfonates, higher alcohol sulfates, alkyl ether sulfates. And sulfate ester salts such as alkyl phosphate esters and the like.

  Nonionic surfactants include, for example, ether types such as polyoxyethylene alkyl ether, ether ester types such as glycerin ester polyoxyethylene ether, ester types such as polyethylene glycol fatty acid ester, glycerin ester, and sorbitan ester. Can be mentioned.

  The acrylic acid polymer may be a homopolymer or a copolymer. The homopolymer preferably includes a homopolymer containing the structural unit (A) derived from the monomer (a) such as acrylic acid, a non-metallic salt of acrylic acid, or an acrylic ester. As the copolymer, preferably, the structural unit (A) derived from at least one monomer (a) selected from the group consisting of acrylic acid, a non-metallic salt of acrylic acid, and an acrylic ester, and the following monomer ( Each structural unit derived from at least two types of monomers (a) selected from the group consisting of a copolymer comprising the structural unit (B) derived from b), acrylic acid, a non-metallic salt of acrylic acid, and an acrylic ester Mention may be made of copolymers comprising (A).

  Examples of acrylic acid nonmetal salts include ammonium acrylate salts and amine acrylate salts. The acrylic acid polymer may contain one or more kinds of structural units derived from these non-acrylic acid metal salts.

  When the acrylic acid polymer is a copolymer, the structural unit (A) is contained in an amount exceeding 50 mol%, preferably exceeding 70 mol%, and exceeding 80 mol%. It is more preferable if it contains, and it is further more preferable if it contains exceeding 90 mol%.

  The monomer (b) is a monomer having a carboxylic acid (salt) group and having a polymerizable double bond, such as itaconic acid, itaconic anhydride, methacrylic acid, maleic acid, Maleic anhydride, fumaric acid, fumaric anhydride, citraconic acid, citraconic anhydride, glutaconic acid, vinyl acetic acid, allyl acetic acid, phosphinocarboxylic acid, α-haloacrylic acid, β-carboxylic acid, or salts thereof, methacrylic And alkyl methacrylates such as methyl acrylate, ethyl methacrylate, and octyl methacrylate.

  When the acrylic acid polymer is a salt, it can be obtained, for example, by polymerizing an acid acrylic monomer alone or copolymerizing with the monomer (b) and then neutralizing with a predetermined alkali. . Examples of the salt include an ammonium salt of a copolymer of acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid.

  From the viewpoint of improving dispersion stability, the acrylic acid polymer is preferably at least one selected from the group consisting of polyacrylic acid and ammonium polyacrylate, and more preferably ammonium polyacrylate.

  The weight average molecular weight of the acrylic acid polymer is preferably 500 to 50,000, more preferably 500 to 10,000, and further preferably 1,000 to 10,000 from the viewpoint of improving dispersion stability.

The weight average molecular weight is a value calculated based on a peak in a chromatogram obtained by applying a gel permeation chromatography (GPC) method under the following conditions.
Column: G4000PWXL + G2500PWXL (Tosoh Corporation)
Eluent: (0.2 M phosphate buffer) / (CH ₃ CN) = 9/1 (volume ratio)
Flow rate: 1.0 mL / min
Column temperature: 40 ° C
Detector: RI detector Standard material: Polyacrylic acid equivalent

  The content of the dispersant in the polishing composition is preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, and still more preferably 0.002% by weight or more, from the viewpoint of improving dispersion stability. It is. The content of the dispersant in the polishing composition is preferably 0.5% by weight or less, more preferably 0.1% by weight or less, and still more preferably 0.05% by weight or less. Therefore, the content of the dispersant is preferably 0.0005 to 0.5% by weight, more preferably 0.001 to 0.1% by weight, and still more preferably 0.002 to 0.05% by weight.

  The content of each component described above is the content at the time of use, but the polishing composition of the present embodiment is stored and supplied in a concentrated state as long as the stability is not impaired. May be. In this case, it is preferable in that the production / transport cost can be reduced. The concentrate may be used after appropriately diluted with the above-mentioned aqueous medium as necessary.

  When the polishing liquid composition of the invention of this embodiment is the concentrated liquid, the content of the composite oxide particles is preferably 2% by weight or more, more preferably 3% by weight from the viewpoint of reducing production / transport costs. As mentioned above, More preferably, it is 5 weight% or more, More preferably, it is 10 weight% or more. Further, from the viewpoint of improving dispersion stability, the content of the composite oxide particles is preferably 50% by weight or less, more preferably 40% by weight or less, and still more preferably 30% by weight or less. Therefore, the content of the composite oxide particles is preferably 2 to 50% by weight, more preferably 3 to 40% by weight, still more preferably 5 to 30% by weight, and still more preferably 10 to 30% by weight.

  The polishing composition of this embodiment may further contain at least one optional component selected from a pH adjuster, a preservative, and an oxidizing agent as long as the effects of the present invention are not hindered. .

  Examples of the pH adjuster include basic compounds and acidic compounds. Examples of basic compounds include ammonia, potassium hydroxide, water-soluble organic amines and quaternary ammonium hydroxides. Examples of the acidic compound include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and organic acids such as acetic acid, oxalic acid, succinic acid, glycolic acid, malic acid, citric acid and benzoic acid.

  Examples of preservatives include benzalkonium chloride, benzethonium chloride, 1,2-benzisothiazolin-3-one, (5-chloro-) 2-methyl-4-isothiazolin-3-one, hydrogen peroxide, or hypochlorite Examples include acid salts.

  Examples of the oxidizing agent include peroxides such as permanganic acid and peroxo acid, chromic acid, nitric acid, and salts thereof.

  The pH at 25 ° C. of the polishing composition of the present embodiment is not particularly limited, but is preferably 2 to 10, more preferably 3 to 9, more preferably 4 to 8, since the polishing rate can be further improved. More preferably, it is 4.5-7. Here, the pH at 25 ° C. can be measured using a pH meter (Toa Denpa Kogyo Co., Ltd., HM-30G), and is a value one minute after immersion of the electrode in the polishing composition.

  Next, an example of a method for preparing the polishing composition of this embodiment will be described.

  An example of the manufacturing method of the polishing liquid composition of this embodiment is not restrict | limited at all, For example, it can prepare by mixing composite oxide particle | grains, a dispersing agent, an aqueous medium, and an arbitrary component as needed. .

  The dispersion of the composite oxide particles in the aqueous medium can be performed using, for example, a stirrer such as a homomixer, a homogenizer, an ultrasonic disperser, a wet ball mill, or a bead mill. After the composite oxide particles are dispersed in the aqueous medium, when the coarse particles formed by aggregation of the composite oxide particles are contained in the aqueous medium, it is preferable to remove the coarse particles by centrifugation, filter filtration, or the like. . The composite oxide particles are preferably dispersed in an aqueous medium in the presence of a dispersant.

  Next, a polishing method using the polishing composition of this embodiment will be described.

  In an example of the polishing method performed using the polishing liquid composition of the present embodiment, the polishing liquid composition is supplied between the polishing object and the polishing pad constituting the polishing apparatus, and the polishing object and the polishing pad The polishing object is polished by moving the polishing pad relative to the polishing object while in contact with the polishing object.

  The polishing pad is attached to a polishing surface plate such as a rotary table, for example. The object to be polished is held by a carrier or the like. The polishing apparatus may be a double-side polishing apparatus capable of simultaneously polishing both main surfaces of a plate-like object to be polished, or may be a single-side polishing apparatus capable of polishing only one surface.

(Polishing substrate of glass substrate)
There is no restriction | limiting in particular about the material of the polishing pad used for grinding | polishing of the base material of a glass substrate, A conventionally well-known thing can be used.

  Examples of the material of the base material to be polished include quartz glass, soda lime glass, aluminosilicate glass, boron silicate glass, aluminoboron silicate glass, alkali-free glass, crystallized glass, and glassy carbon. . Among these, the polishing liquid composition of the present embodiment is a base material of an aluminosilicate glass substrate that is an example for a tempered glass substrate, a base material that becomes a glass ceramic substrate (crystallized glass substrate) by being polished, It is suitable for polishing a base material that becomes a synthetic quartz glass substrate by polishing. The base material of the aluminosilicate glass substrate has good chemical durability and is less susceptible to damage (such as recess defects) due to alkali cleaning performed for the purpose of removing particles remaining on the substrate after polishing. It is preferable in that a glass substrate with high surface quality can be provided. A synthetic quartz glass substrate is preferable in that it has excellent optical characteristics such as transmittance.

  There is no restriction | limiting in particular about the shape of the base material of a glass substrate, For example, the shape which has flat parts, such as a disk shape, plate shape, slab shape, prism shape, and the shape which has curved surface parts, such as a lens, etc. are mentioned. The polishing composition of the present embodiment is particularly suitable for polishing a substrate of a disk-shaped or plate-shaped glass substrate.

  From the viewpoint of improving the polishing rate, the polishing load applied to the base material of the glass substrate by the polishing apparatus is preferably 3 kPa or more, more preferably 4 kPa or more, further preferably 5 kPa or more, and even more preferably 5.5 kPa or more. Further, from the viewpoint of improving the quality of the polished surface and relaxing the residual stress on the polished surface, the polishing load is preferably 12 kPa or less, more preferably 11 kPa or less, further preferably 10 kPa or less, and even more preferably 9 kPa or less. Accordingly, the polishing load is preferably 3 to 12 kPa, more preferably 4 to 11 kPa, still more preferably 5 to 10 kPa, and even more preferably 5.5 to 9 kPa.

The supply rate of the polishing liquid composition varies depending on the sum of the area of the surface of the polishing pad facing the polishing object and the area of the polishing target surface of the substrate of the glass substrate and the composition of the polishing liquid composition. From the viewpoint of improving the speed, it is preferably 0.06 to 5 ml / min per 1 cm ^{2 of the} surface to be polished, more preferably 0.08 to 4 ml / min, more preferably 0.1 to 3 ml / min. .

  As for the rotation speed of a polishing pad, 10-200 rpm is preferable, More preferably, it is 20-150 rpm, More preferably, it is 30-60 rpm.

(Thin film polishing performed in the manufacturing process of semiconductor devices)
The polishing liquid composition of this embodiment can also be used, for example, for polishing a thin film in which one main surface of a semiconductor substrate is arranged on the side.

  Examples of the material of the semiconductor substrate include elemental semiconductors such as Si or Ge, compound semiconductors such as GaAs, InP, or CdS, mixed crystal semiconductors such as InGaAs, HgCdTe, and the like.

  Thin film materials include metals such as aluminum, nickel, tungsten, copper, tantalum, and titanium; semi-metals such as silicon; alloys based on the above metals; glassy, glassy carbon, or glassy such as amorphous carbon Substances: Ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, or titanium nitride; materials constituting semiconductor devices such as resins such as polyimide resins. Among these, the thin film preferably contains silicon from the viewpoint that it can be polished at a high speed, and more preferably contains at least one selected from the group consisting of silicon oxide, silicon nitride, and polysilicon. preferable. Examples of silicon oxide include silicon dioxide and tetraethoxysilane (TEOS). The thin film containing silicon oxide may be doped with elements such as phosphorus and boron. Specific examples of such a thin film include BPSG (Boro-Phospho-Silicate Glass) film and PSG (Phospho-Silicate Glass). ) A film etc. are mentioned.

  The thin film forming method may be appropriately selected according to the material constituting the thin film, and examples thereof include a CVD method, a PVD method, a coating method, and a plating method.

  In polishing the thin film, the polishing load applied to the thin film by the polishing apparatus is preferably 5 kPa or more, more preferably 10 kPa or more from the viewpoint of improving the polishing rate. Further, from the viewpoint of improving the quality of the polished surface and relaxing the residual stress on the polished surface, the polishing load is preferably 100 kPa or less, more preferably 70 kPa or less, and even more preferably 50 kPa or less. Therefore, the polishing load is preferably 5 to 100 kPa, more preferably 10 to 70 kPa, and still more preferably 10 to 50 kPa.

The supply rate of the polishing liquid composition varies depending on the sum of the area of the surface of the polishing pad facing the polishing object and the area of the thin film polishing object surface, and the composition of the polishing liquid composition, but improves the polishing speed. From the viewpoint, 0.01 ml / min or more per 1 cm ² of the surface of the polishing object is preferable, and more preferably 0.1 ml / min or more. Further, from the viewpoint of cost reduction and ease of waste liquid treatment, the supply rate of the polishing liquid composition is preferably 10 ml / min or less, more preferably 5 ml / min or less per 1 cm ^{2 of the} surface to be polished. Therefore, the supply rate of the polishing composition is preferably 0.01 to 10 ml / min, more preferably 0.1 to 5 ml / min per 1 cm ^{2 of the} surface to be polished.

  The material of the polishing pad used in the polishing process is not particularly limited, and conventionally known materials can be used. Examples of the material of the polishing pad include organic polymer foams such as hard foamed polyurethane, inorganic foams, etc., among which hard foamed polyurethane is preferable.

  The rotational speed of the polishing pad is preferably 30 to 200 rpm, more preferably 45 to 150 rpm, and still more preferably 60 to 100 pm.

  The thin film may be a thin film having an uneven surface. A thin film having a concavo-convex surface is formed by, for example, a thin film forming process in which one main surface on a semiconductor substrate forms a crocodile thin film, and a concavo-convex surface formation in which the semiconductor substrate of this thin film forms a concavo-convex pattern on the opposite surface It can obtain through a process. The concave / convex pattern can be formed using a conventionally known lithography method or the like. In addition, the surface opposite to the surface on the semiconductor substrate side of the thin film may be formed to be uneven corresponding to the unevenness of the lower layer. In polishing a thin film having an uneven surface, it is preferable that the polishing load, the supply rate of the polishing composition, the material of the polishing pad, the number of rotations of the polishing pad, and the like are the same as those for polishing the thin film.

  Polishing of the thin film of this embodiment is suitable when the step (H) between the convex part and the concave part adjacent to each other (see FIG. 1C or FIG. 3A) is preferably 50 to 2000 nm, more preferably 100 to 1500 nm. Used for. “Step (H)” means the distance between the apex of the convex portion and the bottom point of the concave portion, and can be determined by a profile measuring device (trade name HRP-100, manufactured by KLA Tencor).

  The polishing composition of this embodiment can be used for any polishing in the manufacturing process of a semiconductor device. As specific examples, for example, (1) polishing performed in a step of forming an embedded isolation film, (2) polishing performed in a step of planarizing an interlayer insulating film, and (3) embedded metal wiring (for example, damascene wiring) Etc.) and (4) polishing performed in the step of forming the embedded capacitor.

  Examples of the semiconductor device include a memory IC (Integrated Circuit), a logic IC, and a system LSI (Large-Scale Integration).

  The polishing liquid composition of the present embodiment includes a glass substrate base material constituting a hard disk and the like, a base material of a crystallized glass substrate such as a glass ceramic substrate, a photomask substrate, in addition to an insulating layer constituting a semiconductor device. The present invention can also be applied to polishing of a base material of a synthetic quartz glass substrate used as a glass substrate or a glass surface of a liquid crystal display panel.

  Next, polishing performed in the process of forming the buried element isolation film in the manufacturing process of the semiconductor device will be described with reference to the drawings.

As shown in FIG. 1A, a silicon nitride (SiN ₄ ) film 2 is formed on a silicon dioxide oxide film (not shown) formed by exposing a semiconductor substrate 1 to oxygen in an oxidation furnace, for example, by a CVD method (chemical process). Vapor phase growth method). Next, as shown in FIG. 1B, a shallow trench is formed using a photolithography technique. Next, as shown in FIG. 1C, an oxide film (SiO ₂ film) 3 for filling the trench is formed by, for example, a CVD method using silane gas and oxygen gas. The surface opposite to the side of the semiconductor substrate 1 of the oxide film 3 formed in this way has irregularities having a level difference H formed corresponding to the irregularities of the lower layer. Next, the oxide film 3 is polished by CMP until the surface of the silicon nitride film 2 and the surface of the oxide film 3 are substantially flush (see FIG. 1D). The polishing composition of this embodiment is used when polishing by this CMP method.

  Next, polishing performed in the step of planarizing the interlayer insulating film in the manufacturing process of the semiconductor device will be described with reference to the drawings.

As shown in FIG. 2A, a metal thin film 19 (for example, an Al thin film) is formed on one main surface of the semiconductor substrate 11 by sputtering, for example. In the example shown in FIG. 2A, a source 12 and a drain 13 are formed in the semiconductor substrate 11 as an impurity diffusion region doped with impurities. In this figure, below the metal thin film 19, there are a gate electrode 15 whose surface is silicided, sidewalls 14 disposed at both ends of the gate electrode 15, insulating layers 16 and 17 made of SiO _{2 and the} like. A tungsten plug 18 is disposed through the insulating layers 16 and 17 to connect the metal thin film 19 and the gate electrode 15 to each other.

  Next, as shown in FIG. 2B, the metal thin film 19 is patterned using a photolithography technique and a dry etching technique to form an extraction electrode 20. Thereby, the CMOS structure is completed.

Next, as shown in FIG. 3A, an oxide film (SiO ₂ film) 21 is formed by, for example, a CVD method using silane gas and oxygen gas. The opposite surface of the oxide film 21 to the surface facing the semiconductor substrate 11 has an unevenness having a step H formed corresponding to the unevenness of the lower layer. Next, the oxide film 21 is polished by CMP (see FIG. 3B). The polishing composition of this embodiment is used when polishing by this CMP method.

<Polishing object>
1. A base material of an aminosilicate glass substrate for hard disk A base material of an aminosilicate glass substrate for hard disk (hereinafter abbreviated as “glass base material”) was prepared. This glass substrate is polished in advance using a polishing composition containing ceria particles as an abrasive, and the surface roughness is 0.3 nm (AFM-Ra), the thickness is 0.635 mm, and the outer The diameter is 65 mm and the inner diameter is 20 mm.

2. Synthetic Quartz Wafer A synthetic quartz wafer (manufactured by Optstar Co., Ltd.) having a diameter of 5.08 cm (2 inches) and a thickness of 1.0 mm was prepared.

3. Silicon wafer with TEOS (tetraethoxysilane) film TEOS with a thickness of 2000 nm formed on a silicon wafer having a diameter of 20.32 cm (8 inches) by a parallel plate type plasma chemical vapor deposition method (p-CVD method) A membrane was prepared.

4). Silicon wafer with thermal oxide film A silicon dioxide film having a thickness of 2000 nm formed on a silicon wafer having a diameter of 20.32 cm (8 inches) was prepared. The silicon dioxide film can be formed by placing a silicon wafer in an oxidation furnace and exposing it to oxygen gas or steam to cause the silicon in the silicon wafer to react with oxygen.

5. Silicon wafer with HDP film A silicon oxide film having a thickness of 1000 nm formed by high-density plasma chemical vapor deposition (HDP-CVD) on a silicon wafer having a diameter of 20.32 cm (8 inches) was prepared.

<Polishing conditions>
1. Glass substrate or synthetic quartz wafer polishing and polishing tester: Musashino Electronics, MA-300 single-side polishing machine, surface plate diameter 300 mm polishing pad: laminated pad of IC1000 (hard urethane pad) and suba400 (nonwoven fabric type pad) Nitta Haas Co., Ltd.) or NP025 (Suede type pad, manufactured by fillwel Co., Ltd.)
Plate rotation speed: 90r / min
Carrier rotation speed: 90 r / min, forced drive polishing composition supply rate: 50 g / min (about 1.5 mL / min / cm ² )
Polishing time: 15 min
Polishing load: 300 g / cm ² (constant load by weight)
Dressing conditions: Ion exchange water was supplied to the brush for 1 minute before polishing to dress the brush.

2. TEOS film, thermal oxide film, or HDP film polishing / polishing tester: single-sided polishing machine (part number: LP-541, manufactured by Lapmaster SFT, surface plate diameter 540 mm)
Polishing pad: Laminated pad of IC1000 (hard urethane pad) and suba400 (nonwoven fabric type pad) (made by Nitta Haas Co., Ltd.)
Surface plate rotation speed: 100 rpm
Head rotation speed: 110 rpm (the rotation direction is the same as the surface plate)
Polishing time: 1 min
Polishing load: 30 kPa (set value)
Polishing liquid composition supply amount: 200 ml / min

<Evaluation method>
After polishing an object to be polished using the polishing liquid compositions of Examples 1 to 20 and Comparative Examples 1 to 14 (see Tables 1 to 3), washed with running water using ion-exchanged water, and then ion-exchanged Ultrasonic cleaning (100 kHz, 3 min) while immersed in water, further cleaning with running water with ion-exchanged water, and finally drying by spin dry method.

(Preparation of abrasive slurry)
(1) Ce _0.75 Zr _0.25 O ₂ particle slurry In a water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) has been added, a fired product A (Ce _0.75 Zr) is obtained by a bead mill so that the volume median diameter becomes 150 nm. _0.25 O ₂ particles) Ce _0.75 Zr _0.25 O ₂ particle slurry obtained by is wet milling (Ce _0.75 Zr _0.25 O ₂ particles: were prepared 25 wt%). The fired product A is obtained by firing unfired Ce _0.75 Zr _0.25 O ₂ particles (trade name Actalys 9320, manufactured by Rhodia) in a continuous firing furnace at 1160 ° C. for 6 hours. The fired product A is obtained using a cerium (IV) compound and a zirconium (IV) compound as raw materials.

(2) CeO ₂ particle slurry CeO ₂ particles (Bikosky) which is a fired product by a bead mill so that the volume median diameter is 130 nm in water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) is added. A CeO ₂ particle slurry (CeO ₂ particles: 40% by weight) obtained by wet pulverization of a product of 99.9% purity by company was prepared. The CeO ₂ particles are obtained using a cerium (IV) compound as a raw material.

(3) Ce _0.87 Zr _0.13 O ₂ particle slurry In a water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) has been added, the bead B (Ce _0.87 Zr _0.13 O Ce ₂ particles) was obtained by being wet-milled _0.87 Zr _0.13 O ₂ particle slurry (Ce _0.87 Zr _0.13 O ₂ particles: 25 wt%) was prepared. The fired product B is obtained by firing unfired Ce _0.87 Zr _0.13 O ₂ particles (manufactured by Rhodia) at 1100 ° C. for 6 hours in a continuous firing furnace. The fired product B is obtained using a cerium (IV) compound and a zirconium (IV) compound as raw materials.

(4) Ce _0.80 Zr _0.20 O ₂ particle slurry In a water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) has been added, a calcined product C (Ce _0.80 Zr) is obtained by a bead mill so that the volume median diameter becomes 150 nm. _0.20 Ce O ₂ particles) was obtained by being wet-milled _0.80 Zr _0.20 O ₂ particle slurry (Ce _0.80 Zr _0.20 O ₂ particles: were prepared 25 wt%). The fired product C is obtained by firing unfired Ce _0.80 Zr _0.20 O ₂ particles (trade name Actalys 9315, manufactured by Rhodia) at 1160 ° C. for 6 hours in a continuous firing furnace. The fired product C is obtained using a cerium (IV) compound and a zirconium (IV) compound as raw materials.

(5) Ce _0.62 Zr _0.38 O ₂ particle slurry In a water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) has been added, a fired product D (Ce _0.62 Zr) is obtained by a bead mill so that the volume median diameter becomes 150 nm. _0.38 Ce O ₂ particles) was obtained by being wet-milled _0.62 Zr _0.38 O ₂ particle slurry (Ce _0.62 Zr _0.38 O ₂ particles: were prepared 25 wt%). The fired product D is obtained by firing unfired Ce _0.62 Zr _0.38 O ₂ particles (trade name Actals 9330, manufactured by Rhodia) in a continuous firing furnace at 1240 ° C. for 6 hours. The fired product D is obtained using a cerium (IV) compound and a zirconium (IV) compound as raw materials.

(6) Unsintered Ce _0.80 Zr _0.20 O ₂ particle slurry Unsintered Ce _0.80 Zr by a bead mill so that the volume median diameter becomes 150 nm in water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) is added. _An unfired Ce _0.80 Zr _0.20 O ₂ particle slurry (Ce _0.80 Zr _0.20 O ₂ particles: 25% by weight) obtained by wet pulverization of _0.20 O ₂ particles (trade name Actals 9315, manufactured by Rhodia) was prepared. The unfired Ce _0.80 Zr _0.20 O ₂ particles are obtained using cerium (IV) compound and zirconium (IV) compound as raw materials.

(7) Unsintered Ce _0.62 Zr _0.38 O ₂ particle slurry Unsintered Ce _0.62 Zr by a bead mill so that the volume median diameter becomes 150 nm in water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) is added. _An unfired Ce _0.62 Zr _0.38 O ₂ particle slurry (Ce _0.62 Zr _0.38 O ₂ particles: 25% by weight) obtained by wet pulverizing _0.38 O ₂ particles (trade name Actals 9330, manufactured by Rhodia) was prepared. The unfired Ce _0.62 Zr _0.38 O ₂ particles are obtained using cerium (IV) compound and zirconium (IV) compound as raw materials.

(8) Ce _0.74 Zr _0.26 O ₂ particle slurry In a water to which a dispersant (ammonium polyacrylate, weight average molecular weight 6000) has been added, a fired product E (Ce _0.74 Zr) is obtained by a bead mill so that the volume median diameter becomes 150 nm. _0.26 O ₂ particles) Ce _0.74 Zr _0.26 O ₂ particle slurry obtained by being wet milling (Ce _0.74 Zr _0.26 O ₂ particles: were prepared 25 wt%). The fired product E is obtained using a cerium (III) compound and a zirconium (IV) compound as raw materials.

Details of Ce _0.74 Zr _0.26 O ₂ process for preparing a particle slurry is as follows.

  First, in a 30 L reaction vessel, 4280 g of a 37.7 wt% cerium (III) nitrate salt solution and 1070 g of a 54.8 wt% zirconium nitrate (IV) salt solution were stirred and mixed. The pH of the obtained liquid mixture was 1.26. Next, 10 L of deionized water was added to the mixture.

  Next, 3.8 mol / L of ammonia water was continuously added to the above mixed solution to which deionized water was added at a supply rate of 1.7 L / hr. When the pH of the liquid mixture thus obtained is 7.2, 1148 ml of 5.8 mol / L hydrogen peroxide water is added, and ammonia water is continuously added so that the pH is stabilized, A coprecipitate of cerium hydroxide and zirconium hydroxide was obtained. The total amount of ammonia water added is 2420 ml, and the amount of hydrogen peroxide water (5.8 M) added is 1148 ml.

Next, the coprecipitate was filtered with a filter paper and washed with deionized water. The obtained washed product was fired at 1130 ° C. for 2 hours, and then coarse particles were removed from the fired product using a 60 mesh filter. Next, the fired product E from which coarse particles were removed by sieving was wet pulverized and then filtered using a pleated filter having a filtration accuracy of 2 μm to obtain a Ce _0.74 Zr _0.26 O ₂ particle slurry.

(Adjustment of polishing composition)
Each slurry adjusted as described above, water, and nitric acid as a pH adjuster are mixed so that the concentrations of the abrasive, dispersant, water, and pH adjuster are the concentrations shown in Tables 1 to 3, respectively. Thus, a polishing liquid composition was obtained.

20 g of each slurry was dried in an atmosphere of 110 ° C. for 12 hours, and then the obtained dried product was crushed with a mortar to obtain a powder X-ray diffraction sample. The results of analyzing each sample by the powder X-ray diffraction method are shown in Table 4. The measurement conditions by the powder X-ray diffraction method were as follows.
(Measurement condition)
Apparatus: Rigaku Co., Ltd., powder X-ray analyzer RINT2500VC
X-ray generation voltage: 40 kV
Radiation: Cu-Kα1 line (λ = 0.154050 nm)
Current: 120 mA
Scan Speed: 10 degrees / min
Measurement step: 0.02 degrees / min

  The height of the apex of each peak, the half width of the first peak, and the area of each peak are calculated from the obtained powder X-ray diffraction spectrum using the powder X-ray diffraction pattern comprehensive analysis software JADE (MDI) attached to the powder X-ray diffractometer. ). The calculation process by the software is performed based on an instruction manual (Jade (Ver. 5) software, instruction manual Manual No. MJ13133E02, Rigaku Corporation) of the software.

<Calculation method of polishing rate>
1. The density of the weight difference of the polishing object before and after polishing for a synthetic quartz wafer glass base material (g), said polishing object (glass substrate 2.46 g / cm ^3, the synthetic quartz wafer 2.20g / cm ^3), The polishing amount per unit time is calculated by dividing by the area of the polishing target surface of the polishing target (glass substrate 30.04 cm ² , synthetic quartz wafer 19.63 cm ² ) and polishing time (min), and polishing rate (Nm / min) was calculated.

2. About TEOS film, thermal oxide film, and HDP film The thickness of the TEOS film before and after polishing was measured using an optical interference film thickness meter (trade name: VM-1000, manufactured by Dainippon Screen Mfg. Co., Ltd.). The polishing rate was calculated from the values as follows. The polishing rate of the thermal oxide film or HDP film was calculated in the same manner.
Polishing rate (nm / min) = (film thickness before polishing) − (film thickness after polishing)

<Scratch number evaluation method>
Polishing Object: Thermally Oxidized Silicon Wafer A silicon dioxide film having a thickness of 1000 nm formed on a silicon wafer having a diameter of 5 cm (2 inches) was prepared. The silicon dioxide film can be formed by placing a silicon wafer in an oxidation furnace and exposing it to oxygen gas or steam to cause the silicon in the silicon wafer to react with oxygen.
Polishing conditions Polishing tester: Musashino Electronics, MA-300 single-side polishing machine, surface plate diameter 300 mm,
Polishing pad: Laminated pad of IC1000 (hard urethane pad) and suba400 (nonwoven fabric type pad) (manufactured by Nitta Haas Co., Ltd.)
Surface plate rotation speed: 90 r / min,
Carrier rotation speed: 90 r / min, forced drive type,
Polishing liquid composition supply rate: 50 g / min (about 1.5 mL / min / cm ² ),
Polishing time: 1 min
Polishing load: 300 g / cm ² (constant load by weight)
Dressing conditions: Ion exchange water was supplied for 1 minute before polishing and dressed with a diamond ring.

  About each said grinding | polishing target object grind | polished according to the said grinding | polishing conditions using each polishing liquid composition, the number of scratches (book) was measured with the following measuring method. The number of n was 3, and the average number of scratches (lines) observed for each polishing object is shown in Table 3.

  Note that the scratch is a scratch having a width of 20 nm or more, a length of 50 μm or more, and a depth of about 3 nm or more that can be observed with MicroMax VMX-2100.

[Measurement method of the number of scratches]
Measuring device: VISION PSYTEC, MicroMax VMX-2100
(Micromax measurement conditions)
Light source: 2Sλ (250 W) and 3Pλ (250 W), both with 100% light
Chilled angle: -9 °
Magnification: Maximum (Field range: 1/35 of the total area of the polished surface)
Observation area: Total area of polished surface (2 inch thermal oxide film wafer substrate)
Iris: notch

  Tables 1 to 3 show polishing rates of polishing using the polishing liquid compositions of Examples 1 to 20 and Comparative Examples 1 to 14. As shown in Tables 1 to 3, when Examples and Comparative Examples having the same abrasive grain concentration are compared, any of a glass substrate, a synthetic quartz wafer, a TEOS film, a thermal oxide film, and an HDP film is polished. Even in this case, it was confirmed that polishing with the polishing liquid composition of the example had a higher polishing rate than polishing with the polishing liquid composition of the comparative example.

Further, as shown in Tables 3 and 4, when polishing the thermal oxide film using the polishing composition, (the height of the apex of peak a ₁ / the height of the apex of the first peak) × 100 and In the case of using a polishing composition containing complex oxide particles in which both (the height of the apex of peak a ₂ / the height of the apex of the first peak) × 100 is 6.0% or less, (the apex of peak a ₁ Of at least one of the height of the peak / the height of the peak of the first peak) × 100 and the height of the peak of the peak a ₂ / the height of the peak of the first peak × 100 It was confirmed that the number of scratches can be greatly reduced as compared with the case of using a polishing liquid composition containing oxide particles.

  If polishing is performed using the polishing liquid composition of the present embodiment, the object to be polished can be polished at a higher speed and scratches can be reduced. Therefore, the polishing liquid composition of the present embodiment is an oxide film that constitutes a semiconductor device. (For example, silicon oxide film), base material of chemically strengthened glass substrate such as aluminosilicate glass substrate, base material of crystallized glass substrate such as glass ceramic substrate, synthetic quartz used as lens material for photomask or stepper It is suitably used for polishing a substrate of a glass substrate or a glass surface of a liquid crystal display panel.

A to D are process cross-sectional views illustrating an example of a method for manufacturing a semiconductor device of the present embodiment or an example of a polishing method of the present embodiment. A and B are process cross-sectional views illustrating an example of a method for manufacturing a semiconductor device of the present embodiment or an example of a polishing method of the present embodiment. A and B are process cross-sectional views illustrating an example of a method for manufacturing a semiconductor device of the present embodiment or an example of a polishing method of the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Semiconductor substrate 2 Silicon nitride film 3, 16, 17, 21 Oxide film 12 Source 13 Drain 14 Side wall 15 Gate electrode 18 Tungsten plug 19 Metal thin film 20 Lead electrode

Claims (6)

A polishing liquid composition comprising composite oxide particles containing cerium and zirconium, a dispersant, and an aqueous medium,
In the powder X-ray diffraction spectrum of the composite oxide particles obtained by irradiating with CuKα1 rays (λ = 0.154050 nm),
A peak (first peak) having a peak within a diffraction angle 2θ (θ is a black angle) region 28.61 to 29.67 °,
A peak having a peak in the diffraction angle 2θ region 33.14 to 34.53 ° (second peak),
A peak (third peak) having an apex within a diffraction angle 2θ region of 47.57 to 49.63 °,
Each has a peak (fourth peak) having a vertex within the diffraction angle 2θ region of 56.4 to 58.91 °,
The half width of the first peak is 0.8 ° or less,
When at least one of peak a ₁ derived from cerium oxide and peak a ₂ derived from zirconium oxide is present in the powder X-ray diffraction spectrum,
A polishing liquid composition, wherein the height of the peaks a ₁ and a ₂ is 6.0% or less of the height of the peak of the first peak.
However, the apex of the peak a ₁ exists in a diffraction angle 2θ region of 28.40 to 28.59 °, and the apex of the peak a ₂ exists in a diffraction angle 2θ region of 29.69 to 31.60 °. The area of the second peak is 10 to 50% of the area of the first peak,
The area of the third peak is 35 to 75% of the area of the first peak;
The polishing composition according to claim 1, wherein the area of the fourth peak is 20 to 65% of the area of the first peak. The polishing composition according to claim 1 or 2 , wherein the composite oxide particles have a volume median diameter of 30 to 1000 nm. Wherein between the object to be polished and the polishing pad, supplying a polishing liquid composition according to any one of claims 1 to 3, in a state where the polishing object and the polishing pad are in contact, said polishing pad A polishing method comprising a step of polishing the polishing object by causing relative movement with respect to the polishing object. The manufacturing method of a glass substrate including the grinding | polishing process of grind | polishing at least one main surface of the both main surfaces of the base material of a glass substrate using the polishing liquid composition in any one of Claims 1-3 . A thin film forming process in which one main surface on the semiconductor substrate forms a thin film on the alligator;
The method of manufacturing a semiconductor device including a polishing step of polishing using the polishing composition according to the thin film in any of claims 1-3.

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