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WO2018142516A1 - Liquide de polissage, ensemble de liquide de polissage, et procédé de polissage - Google Patents

Liquide de polissage, ensemble de liquide de polissage, et procédé de polissage Download PDF

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Publication number
WO2018142516A1
WO2018142516A1 PCT/JP2017/003645 JP2017003645W WO2018142516A1 WO 2018142516 A1 WO2018142516 A1 WO 2018142516A1 JP 2017003645 W JP2017003645 W JP 2017003645W WO 2018142516 A1 WO2018142516 A1 WO 2018142516A1
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WIPO (PCT)
Prior art keywords
polishing
liquid
insulating material
polishing liquid
mass
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Ceased
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PCT/JP2017/003645
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English (en)
Japanese (ja)
Inventor
利明 阿久津
陽介 星
雅子 青木
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Resonac Corp
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Hitachi Chemical Co Ltd
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Priority to PCT/JP2017/003645 priority Critical patent/WO2018142516A1/fr
Publication of WO2018142516A1 publication Critical patent/WO2018142516A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00—Materials not provided for elsewhere
    • C09K3/14—Anti-slip materials; Abrasives
    • H10P52/00—

Definitions

  • the present invention relates to a polishing liquid, a polishing liquid set, and a polishing method.
  • the present invention relates to a polishing liquid, a polishing liquid set, and a polishing method that can be used in a planarization process of a substrate surface, which is a technique for manufacturing semiconductor elements.
  • the present invention relates to a polishing liquid that can be used in a planarization process of a shallow trench isolation (shallow trench isolation, hereinafter referred to as “STI”) insulating material, premetal insulating material, interlayer insulating material, etc.
  • STI shallow trench isolation
  • CMP Chemical Mechanical Polishing
  • Polishing liquid generally contains abrasive grains.
  • abrasive grains it is known to use silica (silicon oxide) particles such as fumed silica and colloidal silica, alumina (aluminum oxide) particles, ceria (cerium oxide) particles, and the like.
  • a stopper for example, a stopper film, also referred to as a “polishing stop layer”
  • a stopper film also referred to as a “polishing stop layer”
  • a laminate having a substrate having a concavo-convex pattern, a stopper disposed on a convex portion of the substrate, and an insulating material disposed on the substrate and the stopper so as to fill the concave portion is polished. Unnecessary portions of the insulating material are removed.
  • polishing of the stopper is not sufficiently suppressed, it is difficult to stop polishing when the stopper is exposed, and polishing proceeds excessively. As a result, a difference occurs in the thickness of the stopper and / or the thickness of the element isolation insulating material, which may result in a defective product. Therefore, in the CMP process for forming the STI, it is preferable that the ability to suppress the polishing of the stopper is higher, and the ability to suppress the polishing speed of the stopper material is increased, and the polishing selectivity of the insulating material with respect to the stopper material is increased. There is a need for polishing liquids that can be improved.
  • the present invention is intended to solve such a technical problem, and an object thereof is to provide a polishing liquid, a polishing liquid set, and a polishing method capable of improving the polishing selectivity of an insulating material with respect to a stopper material.
  • the inventors of the present invention have disclosed a polishing compound containing a hydroxide of a tetravalent metal element, a polyalkylene glycol, a specific polymer compound containing at least one selected from the group consisting of a carboxyl group and a carboxylate group, and a positive polymer compound. It has been found that the above problem can be solved by using a polishing liquid containing an ionic polymer and a liquid medium.
  • a polishing liquid according to the present invention contains abrasive grains containing a hydroxide of a tetravalent metal element, polyalkylene glycol, a polymer compound, a cationic polymer, and a liquid medium, and the polymer compound Has a first molecular chain to which a functional group is directly bonded and a second molecular chain branched from the first molecular chain, wherein the functional group is a group consisting of a carboxyl group and a carboxylate group. Including at least one selected.
  • the insulating material can be polished at a high polishing rate, and the polishing rate of the stopper material can be sufficiently suppressed, and the polishing selectivity of the insulating material with respect to the stopper material is improved. Can do.
  • anionic polymers polycarboxylic acid, polysulfonic acid, etc.
  • the anionic polymer is used in a polishing liquid containing abrasive grains containing a hydroxide of a tetravalent metal element, the occurrence of polishing flaws is suppressed by the aggregation of the abrasive grains. And the effect of increasing the polishing rate of the insulating material may not be obtained.
  • the insulating material can be polished at a high polishing rate while suppressing the aggregation of abrasive grains (while maintaining dispersion stability), and the polishing rate of the stopper material can be sufficiently suppressed. be able to.
  • over polishing For example, continuing polishing for the same length of time A as polishing the insulating material until the stopper is exposed (a time corresponding to 100% of time A) is referred to as “100% overpolishing”. The amount of overpolishing (how much overpolishing is determined) varies depending on the shape of the substrate to be polished.
  • Patent Document 5 combines a polishing liquid containing hydroxide particles of a tetravalent metal element and a water-soluble polymer with a polishing pad (polishing cloth) having a Shore D hardness of 70 or more. It is disclosed that the flatness is improved. However, when a polishing pad with high hardness is used, polishing scratches may occur in the material to be polished. Therefore, even when a low-hardness polishing pad that is generally used at present and has high versatility is used, it may be required to obtain excellent flatness.
  • the polishing liquid of the present invention it is possible to suppress the progress of dishing when overpolishing is performed, and the flatness after polishing can be improved.
  • the progress of dishing can be suppressed even when a polishing pad having a low hardness (for example, Shore D hardness of 65 or less) is used.
  • the flatness of the film can be improved.
  • the polishing liquid as described above the progress of dishing can be suppressed while improving the polishing selectivity of the insulating material with respect to the stopper material.
  • these insulating materials can be highly planarized in the CMP technique for planarizing the STI insulating material, the premetal insulating material, the interlayer insulating material, and the like.
  • the polishing liquid of the present invention the insulating material can be polished with low polishing scratches while the insulating material is highly planarized.
  • the polyalkylene glycol preferably contains at least one selected from the group consisting of polyethylene glycol and polypropylene glycol. Accordingly, it is possible to suppress the progress of dishing and the generation of polishing flaws on the surface to be polished while further improving the polishing selectivity of the insulating material with respect to the stopper material.
  • the first molecular chain includes a structural unit derived from styrene, a structural unit derived from olefin, a structural unit derived from acrylic acid, a structural unit derived from methacrylic acid, a structural unit derived from maleic acid, and a structural unit derived from vinyl acetate. It is preferable to include a copolymer chain having at least one selected from the group consisting of As a result, the insulating material can be easily polished at a high polishing rate, and the polishing rate of the stopper material can be sufficiently suppressed.
  • the second molecular chain preferably contains at least one selected from the group consisting of a hydrophilic molecular chain and a hydrophobic molecular chain. This makes it easy to polish the insulating material at a high polishing rate while suppressing the aggregation of abrasive grains, and sufficiently suppresses the polishing rate of the stopper material.
  • the second molecular chain preferably contains at least one selected from the group consisting of a polyether chain, a polyvinyl alcohol chain, and a polyvinylpyrrolidone chain. This makes it easy to polish the insulating material at a high polishing rate while suppressing the aggregation of abrasive grains, and sufficiently suppresses the polishing rate of the stopper material.
  • the content of the polymer compound is preferably 0.001 to 0.5% by mass based on the total mass of the polishing liquid. This makes it easy to polish the insulating material at a high polishing rate while suppressing the aggregation of abrasive grains, and to easily suppress the polishing rate of the stopper material. Moreover, it is possible to further suppress the occurrence of polishing scratches on the surface to be polished.
  • the tetravalent metal element hydroxide preferably contains at least one selected from the group consisting of rare earth metal hydroxides and zirconium hydroxides. Accordingly, it is possible to suppress the progress of dishing and the generation of polishing flaws on the surface to be polished while further improving the polishing selectivity of the insulating material with respect to the stopper material.
  • One aspect of the present invention relates to the use of the polishing liquid for polishing a surface to be polished containing silicon oxide. That is, the polishing liquid according to the present invention is preferably used for polishing a surface to be polished containing silicon oxide.
  • the constituents of the polishing liquid are stored separately as a first liquid and a second liquid, and the first liquid includes the abrasive grains and a liquid medium.
  • the second liquid contains the polyalkylene glycol, the polymer compound, the cationic polymer, and a liquid medium. According to the polishing liquid set concerning the present invention, the same effect as the polishing liquid concerning the present invention can be acquired.
  • the polishing method according to the present invention may comprise a step of polishing a surface to be polished using the polishing liquid, and is obtained by mixing the first liquid and the second liquid in the polishing liquid set. You may provide the process of grind
  • One aspect of a polishing method according to the present invention is a method for polishing a substrate having an insulating material and silicon nitride, and includes a step of selectively polishing the insulating material with respect to silicon nitride using the polishing liquid.
  • the method may include a step of selectively polishing the insulating material with respect to silicon nitride using a polishing liquid obtained by mixing the first liquid and the second liquid in the polishing liquid set. Good.
  • polishing liquid or the polishing liquid set by using the polishing liquid or the polishing liquid set, the same effect as the polishing liquid according to the present invention is obtained when the insulating material is selectively polished with respect to silicon nitride. be able to.
  • Another aspect of the polishing method according to the present invention is a method for polishing a substrate having an insulating material and polysilicon, comprising the step of selectively polishing the insulating material with respect to polysilicon using the polishing liquid. And a step of selectively polishing the insulating material with respect to polysilicon using a polishing liquid obtained by mixing the first liquid and the second liquid in the polishing liquid set. Also good.
  • polishing methods by using the polishing liquid or the polishing liquid set, the same effect as the polishing liquid according to the present invention can be obtained when the insulating material is selectively polished with respect to polysilicon. be able to.
  • a polishing liquid capable of suppressing the progress of dishing while improving the polishing selectivity of an insulating material (for example, silicon oxide) with respect to a stopper material (for example, silicon nitride and polysilicon).
  • an insulating material for example, silicon oxide
  • a stopper material for example, silicon nitride and polysilicon.
  • polishing can be sufficiently stopped on the stopper regardless of whether silicon nitride or polysilicon is used as the stopper material.
  • the insulating material can be polished at a high polishing rate, and the polishing rate of silicon nitride can be sufficiently suppressed.
  • the stopper and the insulating material embedded in the recess are excessively polished. Can be suppressed.
  • these insulating materials can be highly planarized in CMP technology for planarizing STI insulating materials, pre-metal insulating materials, interlayer insulating materials, and the like.
  • the insulating material can be polished with low polishing scratches while the insulating material is highly planarized.
  • the polishing liquid or the polishing liquid set for the planarization process of the substrate surface it is possible to provide the use of the polishing liquid or the polishing liquid set for the planarization process of the substrate surface. According to the present invention, it is possible to provide the use of the polishing liquid or the polishing liquid set for the planarization process of the STI insulating material, the premetal insulating material, or the interlayer insulating material. ADVANTAGE OF THE INVENTION According to this invention, use of the polishing liquid or polishing liquid set for the grinding
  • polishing liquid the polishing liquid set, and the polishing method using these according to the embodiment of the present invention will be described in detail.
  • a numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
  • the upper limit value or the lower limit value of a numerical range in a certain step may be replaced with the upper limit value or the lower limit value of a numerical range in another step.
  • the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
  • “A or B” only needs to include either A or B, and may include both.
  • the materials exemplified in the present specification can be used singly or in combination of two or more unless otherwise specified.
  • the content of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. Means.
  • polishing liquid is defined as a composition that touches the surface to be polished during polishing.
  • the phrase “polishing liquid” itself does not limit the components contained in the polishing liquid.
  • the polishing liquid according to the present embodiment contains abrasive grains.
  • Abrasive grains are also referred to as “abrasive particles”, but are referred to herein as “abrasive grains”.
  • the abrasive grains are generally solid particles, and the object to be removed is removed (removed) by the mechanical action of the abrasive grains and the chemical action of the abrasive grains (mainly the surface of the abrasive grains) during polishing.
  • the present invention is not limited to this.
  • the polishing liquid according to this embodiment is, for example, a polishing liquid for CMP.
  • the polishing liquid according to this embodiment contains abrasive grains containing a hydroxide of a tetravalent metal element, polyalkylene glycol, a polymer compound, a cationic polymer, and a liquid medium, and the polymer
  • the compound has a first molecular chain to which a functional group is directly bonded and a second molecular chain branched from the first molecular chain, and the functional group is composed of a carboxyl group and a carboxylate group Including at least one selected from more.
  • anionic polymer the polymer compound containing at least one selected from the group consisting of a carboxyl group and a carboxylate group is referred to as “anionic polymer”.
  • Anionic polymers and cationic polymers exclude polyalkylene glycols.
  • the abrasive grains are characterized by containing a hydroxide of a tetravalent metal element.
  • a hydroxide of a tetravalent metal element is a compound containing a tetravalent metal (M 4+ ) and at least one hydroxide ion (OH ⁇ ).
  • the hydroxide of the tetravalent metal element may contain anions other than hydroxide ions (for example, nitrate ions NO 3 ⁇ and sulfate ions SO 4 2 ⁇ ).
  • a hydroxide of a tetravalent metal element may include an anion (for example, nitrate ion NO 3 ⁇ and sulfate ion SO 4 2 ⁇ ) bonded to the tetravalent metal element.
  • an anion for example, nitrate ion NO 3 ⁇ and sulfate ion SO 4 2 ⁇
  • Abrasive grains containing a hydroxide of a tetravalent metal element are more reactive with an insulating material (eg, silicon oxide) than abrasive grains made of silica, ceria, etc., and polish the insulating material at a higher polishing rate. can do.
  • An abrasive can be used individually by 1 type or in combination of 2 or more types.
  • the abrasive grain other than the abrasive grain containing the hydroxide of a tetravalent metal element the abrasive grain containing a silica, an alumina, a ceria etc. is mentioned, for example.
  • composite particles containing a tetravalent metal element hydroxide and silica can be used as the abrasive grains containing a tetravalent metal element hydroxide.
  • the tetravalent metal element hydroxide preferably contains at least one selected from the group consisting of rare earth metal hydroxides and zirconium hydroxides. From the viewpoint of further improving the polishing rate of the insulating material, the tetravalent metal element hydroxide is more preferably a rare earth metal element hydroxide. Examples of rare earth metal elements that can be tetravalent include lanthanoids such as cerium, praseodymium, and terbium. Among these, lanthanoids are preferable and cerium is more preferable from the viewpoint of further improving the polishing rate of the insulating material. A rare earth metal hydroxide and a zirconium hydroxide may be used in combination, or two or more rare earth metal hydroxides may be selected and used.
  • the lower limit of the tetravalent metal element hydroxide content is 80% by mass or more based on the entire abrasive grains (the entire abrasive grains contained in the polishing liquid). Is preferable, 90 mass% or more is more preferable, 95 mass% or more is further preferable, 98 mass% or more is particularly preferable, and 99 mass% or more is extremely preferable. From the viewpoint of easy preparation of the polishing liquid and further excellent polishing characteristics, the abrasive grains are substantially composed of a hydroxide of a tetravalent metal element (substantially 100% by mass of the abrasive grains are composed of a tetravalent metal element). Most preferred are hydroxide particles).
  • the lower limit of the average particle size of the abrasive in the polishing liquid or the polishing liquid set described later is a viewpoint of further improving the polishing speed of the insulating material, a viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material, From the viewpoint of further suppressing the progress of dishing on the surface to be polished, it is preferably 1 nm or more, more preferably 2 nm or more, further preferably 3 nm or more, particularly preferably 5 nm or more, extremely preferably 10 nm or more, and more preferably 20 nm or more. Even more preferred.
  • the upper limit of the average grain size of the abrasive grains is the viewpoint of further suppressing scratches on the surface to be polished, the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material, and further the progress of dishing on the surface to be polished. From the viewpoint of being suppressed, 300 nm or less is preferable, 250 nm or less is more preferable, 200 nm or less is more preferable, 100 nm or less is particularly preferable, 50 nm or less is extremely preferable, and 30 nm or less is very preferable. From the above viewpoint, the average grain size of the abrasive grains is more preferably 1 to 300 nm, and further preferably 3 to 100 nm.
  • the “average particle diameter” of the abrasive grains means the average secondary particle diameter of the abrasive grains.
  • the average particle size of the abrasive grains is, for example, a light diffraction scattering type particle size distribution meter (for example, product name: N5 manufactured by Beckman Coulter, Inc. or Malvern Instruments Co. Manufactured, trade name: Zetasizer 3000HSA).
  • the hydroxide of the tetravalent metal element has a great influence on the polishing characteristics. Therefore, by adjusting the content of the hydroxide of the tetravalent metal element, the chemical interaction between the abrasive grains and the surface to be polished can be improved, and the polishing rate of the insulating material can be further improved. From this, the lower limit of the content of the hydroxide of the tetravalent metal element is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, based on the total mass of the polishing liquid, and 0.03 More preferably, it is more preferably 0.05% by mass or more.
  • the upper limit of the content of the hydroxide of the tetravalent metal element makes it easy to avoid agglomeration of the abrasive grains, improves the chemical interaction between the abrasive grains and the surface to be polished, and improves the characteristics of the abrasive grains. From the viewpoint of effective utilization, it is preferably 8% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, and particularly preferably 1% by mass or less, based on the total mass of the polishing liquid. Mass% or less is extremely preferable, 0.3 mass% or less is very preferable, and 0.1 mass% or less is even more preferable. From the above viewpoint, the content of the tetravalent metal element hydroxide is more preferably 0.01 to 8% by mass based on the total mass of the polishing liquid.
  • the lower limit of the content of abrasive grains is the viewpoint of further improving the polishing rate of the insulating material, the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material, and the viewpoint of further suppressing the progress of dishing on the surface to be polished. Therefore, based on the total mass of the polishing liquid, 0.005% by mass or more is preferable, 0.01% by mass or more is more preferable, 0.02% by mass or more is further preferable, and 0.03% by mass or more is particularly preferable. 0.04 mass% or more is very preferable, and 0.05 mass% or more is very preferable.
  • the upper limit of the content of the abrasive grains is to increase the storage stability of the polishing liquid, to further improve the polishing selectivity of the insulating material with respect to the stopper material, and the progress of dishing on the surface to be polished and the occurrence of polishing flaws
  • the content is preferably 20% by mass or less, more preferably 15% by mass or less, and still more preferably 10% by mass or less, based on the total mass of the polishing liquid.
  • the content of abrasive grains is more preferably 0.005 to 20% by mass based on the total mass of the polishing liquid.
  • the cost and polishing scratches can be further reduced by further reducing the content of abrasive grains.
  • the content of abrasive grains decreases, the polishing rate of an insulating material or the like tends to decrease.
  • abrasive grains containing a hydroxide of a tetravalent metal element can obtain a predetermined polishing rate even with a small amount, so that the balance between the polishing rate and the advantage of reducing the content of abrasive grains is balanced. Further, the content of abrasive grains can be further reduced.
  • the upper limit of the content of the abrasive grains is preferably 8% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, based on the total mass of the polishing liquid, and 1% by mass.
  • the following is particularly preferable, 0.5% by mass or less is extremely preferable, 0.3% by mass or less is very preferable, and 0.1% by mass or less is even more preferable.
  • the abrasive preferably contains a hydroxide of a tetravalent metal element and satisfies at least one of the following conditions (a) and (b).
  • the “aqueous dispersion” in which the content of abrasive grains is adjusted to a predetermined amount means a liquid containing a predetermined amount of abrasive grains and water.
  • Abrasive grains give an absorbance of 1.00 or more to light having a wavelength of 400 nm in an aqueous dispersion in which the content of the abrasive grains is adjusted to 1.0 mass%.
  • the abrasive gives an absorbance of 1.000 or more to light having a wavelength of 290 nm in an aqueous dispersion in which the content of the abrasive is adjusted to 0.0065% by mass.
  • the polishing rate is further improved by using abrasive grains that give an absorbance of 1.00 or more with respect to light having a wavelength of 400 nm in an aqueous dispersion in which the content of abrasive grains is adjusted to 1.0 mass%. be able to. Although this reason is not necessarily clear, this inventor thinks as follows.
  • the tetravalent metal (M 4+ ), 1 to 3 hydroxide ions (OH ⁇ ), and 1 to 3 anions (X c- ) containing M (OH) a X b (wherein a + b ⁇ c 4) is considered to be produced as part of the abrasive grains.
  • the electron-withdrawing anion (X c ⁇ ) acts to improve the reactivity of hydroxide ions, and the amount of M (OH) a X b increases.
  • polishing rate is improved along with this.
  • grains containing M (OH) a Xb absorb the light of wavelength 400nm, since the abundance of M (OH) a Xb increases and the light absorbency with respect to the light of wavelength 400nm becomes high, polishing rate Is thought to improve.
  • abrasive grains containing a tetravalent metal element hydroxide may contain not only M (OH) a Xb but also M (OH) 4 , MO 2 and the like.
  • examples of the anion (X c ⁇ ) include NO 3 ⁇ and SO 4 2 ⁇ .
  • the abrasive grains containing tetravalent metal element hydroxides contain M (OH) a X b after the abrasive grains are thoroughly washed with pure water and then subjected to the FT-IR ATR (Fourier transform Infrared Spectrometer Attenuated). This can be confirmed by a method of detecting a peak corresponding to an anion (X c ⁇ ) using a total reflection method or a Fourier transform infrared spectrophotometer total reflection measurement method. The presence of anions (X c ⁇ ) can also be confirmed by XPS (X-ray Photoelectron Spectroscopy, X-ray photoelectron spectroscopy).
  • the absorption peak at a wavelength of 400 nm of M (OH) a X b (for example, M (OH) 3 X) is much smaller than the absorption peak at a wavelength of 290 nm described later.
  • the present inventor examined the magnitude of the absorbance using an aqueous dispersion having an abrasive content of 1.0% by mass, which has a relatively large abrasive content and is easily detected with a large absorbance. It has been found that when an abrasive that gives an absorbance of 1.00 or more with respect to light having a wavelength of 400 nm is used in an aqueous dispersion, the polishing rate is improved.
  • the lower limit of the absorbance with respect to light having a wavelength of 400 nm is preferably 1.50 or more, more preferably 1.55 or more, and further preferably 1.60 or more, from the viewpoint that the insulating material can be easily polished at an excellent polishing rate.
  • the polishing rate is further improved by using abrasive grains that give an absorbance of 1.000 or more with respect to light having a wavelength of 290 nm in an aqueous dispersion in which the content of abrasive grains is adjusted to 0.0065% by mass. be able to.
  • a particle containing M (OH) a X b (for example, M (OH) 3 X) generated according to the production conditions of a tetravalent metal element hydroxide has an absorption peak near the wavelength of 290 nm.
  • particles made of Ce 4+ (OH ⁇ ) 3 NO 3 ⁇ have an absorption peak at a wavelength of 290 nm. Therefore, it is considered that the polishing rate is improved as the abundance of M (OH) a Xb increases and the absorbance to light having a wavelength of 290 nm increases.
  • the absorbance with respect to light having a wavelength near 290 nm tends to be detected as it exceeds the measurement limit.
  • the present inventors examined the magnitude of absorbance using an aqueous dispersion having an abrasive content of 0.0065% by mass with a relatively small abrasive content and a low absorbance that is easily detected. It has been found that when an abrasive that gives an absorbance of 1.000 or more with respect to light having a wavelength of 290 nm is used in the aqueous dispersion, the effect of improving the polishing rate is excellent.
  • the lower limit of the absorbance with respect to light having a wavelength of 290 nm is more preferably 1.050 or more, further preferably 1.100 or more, particularly preferably 1.130 or more, from the viewpoint of polishing the insulating material at a further excellent polishing rate. 150 or more is very preferable.
  • the upper limit of absorbance for light having a wavelength of 290 nm is not particularly limited, but is preferably 10.00 or less, for example.
  • a hydroxide of a tetravalent metal element (for example, M (OH) a X b ) tends not to absorb light having a wavelength of 450 nm or more (particularly, a wavelength of 450 to 600 nm). Accordingly, from the viewpoint of polishing the insulating material at a further excellent polishing rate by suppressing the adverse effect on polishing due to containing impurities, the abrasive grains have a content of the abrasive grains of 0.0065% by mass ( In an aqueous dispersion adjusted to 65 ppm, an absorbance of 0.010 or less is preferably given to light having a wavelength of 450 to 600 nm.
  • the absorbance with respect to all light in the wavelength range of 450 to 600 nm does not exceed 0.010 in the aqueous dispersion in which the content of the abrasive grains is adjusted to 0.0065% by mass.
  • the upper limit of the absorbance for light having a wavelength of 450 to 600 nm is more preferably less than 0.010.
  • the lower limit of the absorbance with respect to light having a wavelength of 450 to 600 nm is preferably 0.
  • the absorbance in the aqueous dispersion can be measured using, for example, a spectrophotometer (device name: U3310) manufactured by Hitachi, Ltd. Specifically, for example, an aqueous dispersion in which the content of abrasive grains is adjusted to 1.0 mass% or 0.0065 mass% is prepared as a measurement sample. About 4 mL of this measurement sample is put into a 1 cm square cell, and the cell is set in the apparatus. Next, the absorbance is measured in the wavelength range of 200 to 600 nm, and the absorbance is judged from the obtained chart.
  • a spectrophotometer device name: U3310
  • the polishing liquid according to this embodiment preferably has high transparency to visible light (transparent or nearly transparent by visual observation).
  • the abrasive contained in the polishing liquid according to this embodiment has a light transmittance of 50% with respect to light having a wavelength of 500 nm in an aqueous dispersion in which the content of the abrasive is adjusted to 1.0 mass%. / Cm or more is preferable.
  • the lower limit of the light transmittance is more preferably 60% / cm or more, further preferably 70% / cm or more, particularly preferably 80% / cm or more, extremely preferably 90% / cm or more, 92% / Cm or more is very preferable.
  • the upper limit of the light transmittance is 100% / cm.
  • the abrasive grains present in the aqueous dispersion are particles having a large particle diameter (hereinafter referred to as “coarse particles”). It is considered that there are relatively many.
  • an additive for example, polyvinyl alcohol (PVA)
  • PVA polyvinyl alcohol
  • the number of abrasive grains acting on the surface to be polished per unit area (the number of effective abrasive grains) is reduced, and the specific surface area of the abrasive grains in contact with the surface to be polished is reduced. Conceivable.
  • the abrasive grains present in the aqueous dispersion are in a state of less “coarse particles”.
  • an additive for example, polyvinyl alcohol
  • the number of abrasive grains (number of effective abrasive grains) acting on the surface to be polished per unit area is maintained, and the specific surface area of the abrasive grains in contact with the surface to be polished is maintained. It is considered to be.
  • the polishing liquid has the same particle size measured by a general particle size measuring apparatus, it is visually transparent (high light transmittance) and visually turbid. It has been found that there can be (low light transmittance). From this, it is considered that the coarse particles capable of causing the above-described action contribute to the reduction of the polishing rate even if the amount is so small that it cannot be detected by a general particle size measuring apparatus.
  • the light transmittance is a transmittance for light having a wavelength of 500 nm.
  • the light transmittance can be measured with a spectrophotometer. Specifically, for example, it can be measured with a spectrophotometer U3310 (device name) manufactured by Hitachi, Ltd.
  • an aqueous dispersion in which the content of abrasive grains is adjusted to 1.0% by mass is prepared as a measurement sample. About 4 mL of this measurement sample is put into a 1 cm square cell, and the measurement is performed after setting the cell in the apparatus.
  • the absorbance and light transmittance that the abrasive grains contained in the polishing liquid give in the aqueous dispersion are obtained by removing the solid components other than the abrasive grains and the liquid components other than water, and then the aqueous dispersion having a predetermined abrasive grain content. It can be prepared and measured using the aqueous dispersion. Although it depends on the components contained in the polishing liquid, the solid component or liquid component is removed by, for example, centrifugation using a centrifuge capable of applying a gravitational acceleration of several thousand G or less, or applying a gravitational acceleration of tens of thousands G or more.
  • examples of the method for separating abrasive grains include a chromatography method and a filtration method. Among them, gel permeation chromatography and ultrafiltration are used. At least one selected from the group consisting of When using the filtration method, the abrasive grains contained in the polishing liquid can pass through the filter by setting appropriate conditions.
  • examples of the method for separating abrasive grains include a chromatography method, a filtration method, a distillation method, and the like.
  • Gel permeation chromatography Ultrafiltration and At least one selected from the group consisting of vacuum distillation is preferred.
  • examples of the method for separating the abrasive grains include a filtration method and a centrifugal separation method. In the case of filtration, in the filtrate, in the liquid phase in the case of centrifugation, the tetravalent metal element More abrasive grains containing hydroxide.
  • an abrasive component can be fractionated and / or other components can be fractionated under the following conditions.
  • Sample solution 100 ⁇ L of polishing liquid Detector: manufactured by Hitachi, Ltd., UV-VIS detector, trade name “L-4200” Wavelength: 400nm Integrator: Hitachi, Ltd., GPC integrator, product name “D-2500” Pump: Hitachi, Ltd., trade name “L-7100”
  • Eluent Deionized water Measurement temperature: 23 ° C Flow rate: 1 mL / min (pressure is about 40-50 kg / cm 2 ) Measurement time: 60 minutes
  • the abrasive components contained in the polishing liquid it may not be possible to separate the abrasive components even under the above conditions.In that case, by optimizing the amount of sample solution, column type, eluent type, measurement temperature, flow rate, etc. Can be separated. Further, by adjusting the pH of the polishing liquid, there is a possibility that the distillation time of the components contained in the polishing liquid can be adjusted and separated from the abrasive grains. When there are insoluble components in the polishing liquid, it is preferable to remove the insoluble components by filtration, centrifugation, or the like, if necessary.
  • a hydroxide of a tetravalent metal element can be produced by reacting a salt (metal salt) of a tetravalent metal element with an alkali source (base).
  • the hydroxide of the tetravalent metal element is preferably prepared by mixing a salt of the tetravalent metal element and an alkali solution (for example, an alkaline aqueous solution). Thereby, particles having an extremely fine particle diameter can be obtained, and a polishing liquid further excellent in the effect of reducing polishing scratches can be obtained.
  • an alkali solution for example, an alkaline aqueous solution
  • a hydroxide of a tetravalent metal element can be obtained by mixing a metal salt solution of a salt of a tetravalent metal element (for example, an aqueous metal salt solution) and an alkali solution.
  • a salt of a tetravalent metal element a conventionally known salt can be used without particular limitation, and M (NO 3 ) 4 , M (SO 4 ) 2 , M (NH 4 ) 2 (NO 3 ) 6 , M (NH 4). ) 4 (SO 4 ) 4 (M represents a rare earth metal element), Zr (SO 4 ) 2 .4H 2 O, and the like.
  • M is preferably chemically active cerium (Ce).
  • the polishing liquid according to this embodiment contains an additive.
  • additive means polishing other than the liquid medium and abrasive grains in order to adjust polishing characteristics such as polishing rate and polishing selectivity; polishing liquid characteristics such as abrasive dispersibility and storage stability. It refers to the substance contained in the liquid.
  • the polishing liquid according to this embodiment contains polyalkylene glycol.
  • Polyalkylene glycol can also obtain high flatness by suppressing polishing of the insulating material after exposure of the stopper. By covering the insulating material with the polyalkylene glycol, it is presumed that the progress of polishing by the abrasive grains is alleviated and the polishing rate is prevented from becoming excessively high.
  • polyalkylene glycol examples include polyethylene glycol, polypropylene glycol, polybutylene glycol and the like.
  • the polyalkylene glycol is a group consisting of polyethylene glycol and polypropylene glycol from the viewpoint of suppressing the progress of dishing and the generation of polishing scratches on the surface to be polished while further improving the polishing selectivity of the insulating material with respect to the stopper material. At least one selected from the above is preferable, and polyethylene glycol is more preferable.
  • Polyalkylene glycol can be used singly or in combination of two or more for the purpose of adjusting flat polishing characteristics.
  • the upper limit of the weight average molecular weight of the polyalkylene glycol is preferably 500 ⁇ 10 3 or less, more preferably 200 ⁇ 10 3 or less, still more preferably 100 ⁇ 10 3 or less, and 80 ⁇ from the viewpoint of excellent workability and foamability. 10 3 or less is particularly preferable, 60 ⁇ 10 3 or less is very preferable, 10 ⁇ 10 3 or less is very preferable, and 5000 or less is even more preferable.
  • the lower limit of the weight average molecular weight of the polyalkylene glycol is preferably 200 or more, more preferably 300 or more, still more preferably 400 or more, particularly preferably 500 or more, and extremely preferably 600 or more. From the above viewpoint, the weight average molecular weight of the polyalkylene glycol is more preferably 200 to 500 ⁇ 10 3 .
  • a weight average molecular weight can be measured on condition of the following by the gel permeation chromatography method (GPC) using the calibration curve of a standard polystyrene, for example.
  • Equipment used Hitachi L-6000 (made by Hitachi, Ltd.) Column: Gel pack GL-R420 + Gel pack GL-R430 + Gel pack GL-R440 [trade name, total 3 manufactured by Hitachi Chemical Co., Ltd.]
  • the lower limit of the content of polyalkylene glycol further improves the polishing selectivity of the insulating material with respect to the stopper material, further suppresses the progress of dishing on the surface to be polished and the generation of polishing flaws, and further improves the flatness.
  • 0.05% by mass or more is preferable, 0.1% by mass or more is more preferable, 0.3% by mass or more is further preferable, and 0.4% by mass or more is particularly preferable.
  • 0.5 mass% or more is very preferable.
  • the upper limit of the content of polyalkylene glycol is preferably 5% by mass or less, more preferably 2% by mass or less, and more preferably 1% by mass or less based on the total mass of the polishing liquid from the viewpoint of obtaining an appropriate polishing rate of the insulating material. Is more preferable. From the above viewpoint, the content of polyalkylene glycol is more preferably 0.05 to 5% by mass based on the total mass of the polishing liquid. In addition, when using a some compound as polyalkylene glycol, it is preferable that the sum total of content of each compound satisfy
  • the polishing liquid according to this embodiment contains a branched polymer (branched anionic polymer) containing at least one selected from the group consisting of a carboxyl group and a carboxylate group.
  • the branched polymer has a first molecular chain to which a functional group is directly bonded, and a second molecular chain branched from the first molecular chain.
  • the functional group includes at least one selected from the group consisting of a carboxyl group and a carboxylate group.
  • the carboxylate salt include sodium salt, potassium salt, ammonium salt, amine salt and the like.
  • the branched polymer has an effect of suppressing the polishing rate of the stopper material (for example, silicon nitride and polysilicon) from becoming excessively high (effect as a polishing inhibitor). Further, by using a branched polymer, high flatness can be obtained by suppressing polishing of an insulating material (for example, silicon oxide) after the exposure of the stopper.
  • the specific functional group directly bonded to the first molecular chain is adsorbed and coated on the insulating material and the stopper material, the progress of polishing by the abrasive grains is alleviated and the polishing rate is prevented from becoming excessively high. Presumed to be.
  • the branched polymer is not particularly limited as long as it is a polymer having a first molecular chain directly bonded to the specific functional group and a second molecular chain branched from the first molecular chain. Can do.
  • Examples of the branched polymer include so-called comb polymers.
  • An atom constituting a functional group directly bonded to the first molecular chain does not correspond to an atom constituting the second molecular chain.
  • the phrase “functional group is directly bonded to the first molecular chain” means that the functional group is bonded to the atoms constituting the first molecular chain without any other atoms.
  • the first molecular chain may be the longest molecular chain among the molecular chains constituting the branched polymer.
  • the second molecular chain is a side chain of the first molecular chain.
  • the first molecular chain and / or the second molecular chain may be a carbon chain.
  • the first molecular chain of the branched polymer has a structure unit derived from styrene and a structure derived from olefin from the viewpoint of easily polishing the insulating material at a high polishing rate and easily suppressing the polishing rate of the stopper material. It is preferable to include at least one selected from the group consisting of a unit, a structural unit derived from acrylic acid, a structural unit derived from methacrylic acid, a structural unit derived from maleic acid, and a structural unit derived from vinyl acetate.
  • the olefin include ethylene and propylene.
  • the first molecular chain of the branched polymer is easy to polish the insulating material at a high polishing rate, and from the viewpoint of easily suppressing the polishing rate of the stopper material, from the polyester chain, the polyurethane chain, and the polyamide chain. It is preferable to include at least one selected from the group consisting of:
  • the first molecular chain of the branched polymer facilitates polishing of the insulating material at a high polishing rate, and from the viewpoint of sufficiently suppressing the polishing rate of the stopper material, from the viewpoint of polystyrene chain, polyolefin chain (polyethylene chain, polypropylene chain).
  • the arrangement of the structural units is arbitrary.
  • the copolymer chain for example, (a) a block copolymer chain in which the same type of structural units are continuous, (b) a random copolymer chain in which the structural units A and B are particularly ordered, and (C) An alternating copolymer chain in which structural units A and B are alternately arranged can be mentioned.
  • the branched polymer may have at least one selected from the group consisting of a hydrophilic molecular chain and a hydrophobic molecular chain in the first molecular chain and / or the second molecular chain.
  • the branched polymer may have a hydrophilic structural unit and / or a hydrophilic polymer chain in the first molecular chain and / or the second molecular chain, and the hydrophobic structural unit and / or hydrophobicity. It may have a polymer chain.
  • hydrophilic structural unit examples include a structural unit derived from vinyl alcohol, a structural unit derived from vinyl pyrrolidone, a structural unit derived from acrylic acid, a structural unit derived from methacrylic acid, and a structural unit derived from maleic acid.
  • hydrophilic polymer chain examples include a polyether chain, a polyvinyl alcohol chain, and a polyvinyl pyrrolidone chain.
  • hydrophobic structural unit include a structural unit derived from styrene, a structural unit derived from olefin, and a structural unit derived from vinyl acetate.
  • hydrophobic polymer chain examples include a polyester chain, a polyurethane chain, and a polyamide chain.
  • the first molecular chain of the branched polymer makes it easy to polish the insulating material at a high polishing rate while suppressing aggregation of abrasive grains, and from the viewpoint of easily suppressing the polishing rate of the stopper material. It is preferable to include at least one selected from the group consisting of an acid chain and a copolymer chain having a hydrophobic structural unit and a hydrophilic structural unit. As a copolymer chain having a hydrophobic structural unit and a hydrophilic structural unit, it is easy to polish an insulating material at a high polishing rate while suppressing aggregation of abrasive grains, and a polishing rate of a stopper material is sufficient. From the group consisting of a styrene-acrylic acid copolymer chain, a styrene-methacrylic acid copolymer chain, and a styrene-maleic acid copolymer chain.
  • the second molecular chain preferably contains at least one selected from the group consisting of a hydrophilic molecular chain and a hydrophobic molecular chain from the viewpoint of easily maintaining the dispersion stability of the abrasive grains.
  • polishing selectivity and flatness of the insulating material with respect to the stopper material can be further improved while suppressing aggregation of abrasive grains (for example, abrasive grains containing a hydroxide of a tetravalent metal element).
  • the hydrophilic molecular chain suppresses the aggregation of abrasive grains and facilitates polishing of the insulating material at a high polishing rate, and from the viewpoint of sufficiently suppressing the polishing rate of the stopper material, a polyether chain, polyvinyl alcohol. It preferably contains at least one selected from the group consisting of a chain and a polyvinylpyrrolidone chain, and more preferably contains a polyether chain.
  • the polyether chain may contain a polyoxyalkylene chain from the viewpoint of easily polishing the insulating material at a high polishing rate while suppressing aggregation of abrasive grains and easily suppressing the polishing rate of the stopper material. Preferably, it contains at least one selected from the group consisting of a polyoxyethylene chain, a polyoxypropylene chain, and a polyoxyethylene-polyoxypropylene chain.
  • Hydrophobic molecular chain is a structural unit derived from styrene from the viewpoint of easily polishing the insulating material at a high polishing rate while suppressing aggregation of abrasive grains, and easily suppressing the polishing rate of the stopper material. At least selected from the group consisting of structural units derived from olefins, structural units derived from acrylic acid, structural units derived from methacrylic acid, structural units derived from maleic acid, structural units derived from vinyl acetate, polyester chains, polyurethane chains and polyamide chains.
  • polystyrene chain for example, polyethylene chain and polypropylene chain
  • polyvinyl acetate chain for example, polyester chain, polyurethane chain and polyamide chain
  • polyester chain for example, polyethylene chain and polypropylene chain
  • polyurethane chain for example, polyurethane chain
  • polyamide chain is more preferable.
  • polystyrene chain and polyolefin chains More preferably contains at least one member-option, it is particularly preferred to include a polystyrene chain.
  • branched polymer a polymer having the above-described structure can be used from those generally used as a dispersing agent for particles and the like.
  • Floren GW-1500 manufactured by Kyoeisha Chemical Co., Ltd., polyalkylene glycol-modified styrene-maleic acid copolymer
  • DISPERBYK-190 manufactured by BYK-Chemie GmbH, polyalkylene glycol-modified styrene-maleic acid copolymer
  • TEGO Dispers 755W manufactured by Evonik Industries, polyethylene glycol-modified styrene-maleic acid copolymer
  • FLOREN GW-1500, DISPERBYK-190, and TEGO Dispers 755W are polymers having a branched (comb-type) structure, which have a styrene-maleic acid copolymer chain and are directly attached to the copolymer chain.
  • a hydrophilic polyoxyalkylene chain having a carboxyl group as a functional group to be bonded and branched from the copolymer chain Floren GW-1500 is a polyoxyethylene chain and a propylene oxide-modified polyoxyethylene chain
  • TEGO Dispers 755W Has a polyoxyethylene chain).
  • the branched polymer can be used alone or in combination of two or more for the purpose of adjusting polishing characteristics such as polishing selectivity and flatness.
  • the upper limit of the weight average molecular weight of the branched polymer is preferably 200000 or less, more preferably 150,000 or less, still more preferably 100000 or less, particularly preferably 80000 or less, particularly 60000, from the viewpoint that appropriate workability and foamability are easily obtained. The following is extremely preferable, 40,000 or less is very preferable, and 20000 or less is even more preferable.
  • the lower limit of the weight average molecular weight of the branched polymer is preferably 500 or more, more preferably 1000 or more, still more preferably 2000 or more, and further preferably 5000 from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material and the flatness. The above is particularly preferable, 7500 or more is very preferable, and 9000 or more is very preferable. From the viewpoint, the weight average molecular weight of the branched polymer is more preferably 500 to 200,000.
  • a weight average molecular weight can be measured on condition of the following by the gel permeation chromatography method (GPC) using the calibration curve of a standard polystyrene, for example.
  • Equipment used ACQUITY APC system [manufactured by Waters] Column: Waters ACQUITY APC XT 200 + Waters ACQUITY APC XT 45 + Waters ACQUITY APC XT 45 [trade name, manufactured by Waters, 3 in total]
  • Eluent Tetrahydrofuran Column temperature: 45 ° C
  • Detector ACQUITY Differential refractometer (RI) detector [manufactured by Waters] RI temperature: 45 ° C
  • Data processing Empower 3 [manufactured by Waters] Injection volume: 10 ⁇ L
  • the lower limit of the content of the branched polymer is preferably 0.001% by mass or more based on the total mass of the polishing liquid from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material and the flatness. 0.005% by mass or more is more preferable, 0.01% by mass or more is further preferable, 0.02% by mass or more is particularly preferable, and 0.03% by mass or more is extremely preferable.
  • the upper limit of the content of the branched polymer is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, based on the total mass of the polishing liquid, from the viewpoint of easily obtaining an appropriate polishing rate of the insulating material.
  • the content of the branched polymer is preferably 0.001 to 0.5% by mass based on the total mass of the polishing liquid.
  • the cationic polymer is a polymer having a cationic group or a group that can be ionized into a cationic group in a main chain or a side chain.
  • Examples of the cationic group or the group that can be ionized to the cationic group include an amino group, an imino group, and a cyano group.
  • As the cationic polymer a compound corresponding to the second additive is excluded.
  • the cationic polymer can be obtained by polymerizing at least one monomer component selected from the group consisting of allylamine, diallylamine, vinylamine, ethyleneimine, and derivatives thereof.
  • the cationic polymer is at least one selected from the group consisting of an allylamine polymer, a diallylamine polymer, a vinylamine polymer, and an ethyleneimine polymer from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material. Is preferred.
  • the allylamine polymer is a polymer obtained by polymerizing allylamine or a derivative thereof.
  • the allylamine derivative include alkoxycarbonylated allylamine, methylcarbonylated allylamine, aminocarbonylated allylamine, ureated allylamine and the like.
  • the diallylamine polymer is a polymer obtained by polymerizing diallylamine or a derivative thereof.
  • diallylamine derivatives include methyl diallylamine, diallyldimethylammonium salt, diallylmethylethylammonium salt, acylated diallylamine, aminocarbonylated diallylamine, alkoxycarbonylated diallylamine, aminothiocarbonylated diallylamine, hydroxyalkylated diallylamine, and the like.
  • the ammonium salt include ammonium chloride and ammonium alkyl sulfate (for example, ammonium ethyl sulfate).
  • the vinylamine polymer is a polymer obtained by polymerizing vinylamine or a derivative thereof.
  • the vinylamine derivative include alkylated vinylamine, amidated vinylamine, ethylene oxideated vinylamine, propylene oxided vinylamine, alkoxylated vinylamine, carboxymethylated vinylamine, acylated vinylamine, and ureaated vinylamine.
  • the ethyleneimine polymer is a polymer obtained by polymerizing ethyleneimine or a derivative thereof.
  • the ethyleneimine derivative include aminoethylated acrylic polymer, alkylated ethyleneimine, ureaated ethyleneimine, propylene oxideated ethyleneimine and the like.
  • the cationic polymer may have structural units derived from monomer components other than allylamine, diallylamine, vinylamine, ethyleneimine, and derivatives thereof, such as acrylamide, dimethylacrylamide, diethylacrylamide, hydroxyethylacrylamide, acrylic acid. And may have a structural unit derived from methyl acrylate, methacrylic acid, maleic acid, sulfur dioxide or the like.
  • Cationic polymers include allylamine, allylamine derivatives, diallylamine, diallylamine derivatives, vinylamine, vinylamine derivatives, ethyleneimine or ethyleneimine derivative homopolymers (polyallylamine, poly (allylamine derivatives), polydiallylamine, poly (diallylamine derivatives), Polyvinylamine, poly (vinylamine derivative), polyethyleneimine or poly (ethyleneimine derivative)), or a copolymer having a structural unit derived from allylamine, diallylamine, vinylamine, ethyleneimine or a derivative thereof. Good. In the copolymer, the arrangement of structural units is arbitrary.
  • copolymer examples include (a) a block copolymer in which the same type of structural units are continuous, (b) a random copolymer in which the structural units A and B are particularly ordered, and (c) structural units. Examples thereof include an alternating copolymer in which A and structural units B are alternately arranged.
  • the lower limit of the weight average molecular weight of the cationic polymer is preferably 100 or more, more preferably 300 or more, still more preferably 500 or more, and particularly preferably 1000 or more, from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material. 10,000 or more is very preferable, and 100,000 or more is very preferable.
  • the upper limit of the weight average molecular weight of the cationic polymer is preferably 1000000 or less, more preferably 600000 or less, and even more preferably 500000 or less from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material. From the above viewpoint, the weight average molecular weight of the cationic polymer is more preferably from 100 to 1,000,000.
  • the weight average molecular weight of a cationic polymer can be measured on condition of the following by the gel permeation chromatography method (GPC) using the calibration curve of a standard polystyrene, for example.
  • GPC gel permeation chromatography method
  • Equipment used Hitachi L-6000 type [manufactured by Hitachi, Ltd.]
  • the lower limit of the content of the cationic polymer is preferably 0.0001% by mass or more based on the total mass of the polishing liquid from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material and the flatness. 0.0002 mass% or more is more preferable, 0.0005 mass% or more is further preferable, 0.001 mass% or more is particularly preferable, and 0.002 mass% or more is extremely preferable.
  • the upper limit of the content of the cationic polymer is preferably 5% by mass or less, more preferably 3% by mass or less, based on the total mass of the polishing liquid, from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material.
  • the content of the cationic polymer is preferably 0.0001 to 5% by mass based on the total mass of the polishing liquid.
  • the content of the cationic polymer is a method for producing the insulating material (for example, the type and film deposition conditions). It is preferable to adjust appropriately according to.
  • the polishing liquid according to this embodiment further contains an optional additive (excluding compounds corresponding to polyalkylene glycol, anionic polymer, or cationic polymer) for the purpose of adjusting polishing characteristics and the like. Also good.
  • Optional additives include carboxylic acids, amino acids, oxidizing agents (eg, hydrogen peroxide) and the like. Each of these additives can be used alone or in combination of two or more.
  • the optional additive has an effect of further suppressing an excessive increase in the polishing rate of the stopper material (for example, silicon nitride and polysilicon). Further, by using an optional additive, it is possible to obtain higher flatness by suppressing polishing of the insulating material (for example, silicon oxide) after the exposure of the stopper. It is presumed that when the optional additive covers the insulating material and the stopper material, the progress of polishing by the abrasive grains is alleviated and the polishing rate is prevented from becoming excessively high.
  • the stopper material for example, silicon nitride and polysilicon
  • Carboxylic acid has the effect of stabilizing the pH and further improving the polishing rate of the insulating material.
  • the carboxylic acid include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, and lactic acid.
  • An amino acid has an effect of improving the dispersibility of abrasive grains (for example, abrasive grains containing a hydroxide of a tetravalent metal element) and further improving the polishing rate of the insulating material.
  • Amino acids include arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, histidine, proline, tyrosine, tryptophan, serine, threonine, glycine, alanine, ⁇ -alanine, methionine, cysteine, phenylalanine, leucine, valine, isoleucine, etc. Can be mentioned.
  • the content is 0.0001 to 10 mass based on the total mass of the polishing liquid from the viewpoint of obtaining the additive effect while suppressing sedimentation of the abrasive grains. % Is preferred.
  • the sum total of content of each compound satisfy
  • the liquid medium in the polishing liquid according to this embodiment is not particularly limited, but water such as deionized water or ultrapure water is preferable.
  • the content of the liquid medium may be the remainder of the polishing liquid excluding the content of other components and is not particularly limited.
  • the lower limit of the pH of the polishing liquid according to this embodiment is preferably 2.0 or more, more preferably 2.5 or more, still more preferably 3.0 or more, from the viewpoint of further improving the polishing rate of the insulating material. 5 or higher is particularly preferable, 4.0 or higher is extremely preferable, 5.0 or higher is very preferable, and 5.5 or higher is even more preferable.
  • the upper limit of the pH is preferably 12.0 or less, more preferably 10.0 or less, still more preferably 8.0 or less, particularly preferably 7.5 or less, from the viewpoint of further improving the polishing suppression effect of the stopper material. 0.0 or less is very preferable, and 6.5 or less is very preferable.
  • the pH of the polishing liquid is more preferably 3.0 to 12.0 from the viewpoint of further improving the polishing selectivity of the insulating material with respect to the stopper material and suppressing the progress of dishing and the generation of polishing flaws on the surface to be polished. . Further, the pH of the polishing liquid is more preferably 2.0 to 8.0 from the viewpoint of further excellent storage stability of the polishing liquid and polishing suppression effect of the stopper material.
  • the pH of the polishing liquid is defined as the pH at a liquid temperature of 25 ° C.
  • the pH of the polishing liquid is an acid component such as an inorganic acid or an organic acid; ammonia, sodium hydroxide, tetramethylammonium hydroxide (TMAH), imidazole, alkanolamine (for example, trishydroxymethylaminomethane), triazine (for example, 1, 3) , 5-tris (dimethylaminopropyl) hexahydro-1,3,5-triazine) and the like.
  • TMAH tetramethylammonium hydroxide
  • imidazole alkanolamine (for example, trishydroxymethylaminomethane), triazine (for example, 1, 3) , 5-tris (dimethylaminopropyl) hexahydro-1,3,5-triazine) and the like.
  • a buffer may be added to stabilize the pH.
  • you may add a buffer as a buffer (liquid containing a buffer). Examples of such a buffer include acetate buffer and phthalate buffer
  • the pH of the polishing liquid according to this embodiment can be measured with a pH meter (for example, model number PHL-40 manufactured by Electrochemical Instrument Co., Ltd.). Specifically, for example, after calibrating two pH meters using a phthalate pH buffer solution (pH: 4.01) and a neutral phosphate pH buffer solution (pH: 6.86) as standard buffers, Then, the pH meter electrode is put in the polishing liquid, and the value after 2 minutes has passed and stabilized is measured.
  • the temperature of the standard buffer solution and the polishing solution are both 25 ° C.
  • the polishing liquid according to the present embodiment is a one-part type containing at least abrasive grains containing a hydroxide of a tetravalent metal element, polyalkylene glycol, an anionic polymer, a cationic polymer, and a liquid medium.
  • the slurry may be stored as a polishing liquid, and the constituents of the polishing liquid are mixed into the slurry and the additive liquid so that the slurry (first liquid) and the additive liquid (second liquid) are mixed to become the polishing liquid.
  • the slurry includes, for example, at least abrasive grains and a liquid medium.
  • the additive liquid includes, for example, at least a polyalkylene glycol, an anionic polymer, a cationic polymer, and a liquid medium.
  • the polyalkylene glycol, the anionic polymer, the cationic polymer, the optional additive, and the buffering agent are preferably included in the additive liquid among the slurry and the additive liquid.
  • the constituents of the polishing liquid may be stored as a polishing liquid set divided into three or more liquids.
  • the slurry and additive liquid are mixed immediately before or during polishing to prepare a polishing liquid.
  • the one-component polishing liquid may be stored as a polishing liquid storage liquid in which the content of the liquid medium is reduced, and may be diluted with the liquid medium during polishing.
  • the multi-liquid type polishing liquid set may be stored as a slurry storage liquid and an additive liquid storage liquid with a reduced content of the liquid medium, and may be diluted with the liquid medium during polishing.
  • the polishing liquid is supplied onto the polishing surface plate by directly supplying the polishing liquid; supplying the polishing liquid storage liquid and the liquid medium through separate pipes. , A method of supplying them by merging and mixing them; a method of supplying the polishing liquid stock solution and the liquid medium by mixing them in advance, and the like.
  • the polishing rate can be adjusted by arbitrarily changing the composition of these liquids.
  • a polishing liquid set there are the following methods for supplying the polishing liquid onto the polishing surface plate. For example, a method in which slurry and additive liquid are sent through separate pipes, and these pipes are combined and mixed to supply; a slurry storage liquid, a storage liquid for additive liquid, and a liquid medium are sent through separate pipes.
  • a method of supplying them by mixing and mixing them; a method of supplying the slurry and the additive solution after mixing them; a method of supplying the slurry storage solution, the additive solution storage solution and the liquid medium after mixing them in advance, etc. Can be used. Further, it is possible to use a method of supplying the slurry and the additive liquid in the polishing liquid set onto the polishing surface plate, respectively. In this case, the surface to be polished is polished using a polishing liquid obtained by mixing the slurry and the additive liquid on the polishing surface plate.
  • the polishing liquid set according to the present embodiment may be divided into a polishing liquid containing at least the essential component and an additive liquid containing at least an optional component such as an oxidizing agent (for example, hydrogen peroxide). .
  • polishing is performed using a mixed liquid obtained by mixing the polishing liquid and the additive liquid (the mixed liquid also corresponds to the “polishing liquid”).
  • the polishing liquid set according to the present embodiment is a polishing liquid set divided into three or more liquids, a liquid containing at least a part of the essential components, a liquid containing at least the remainder of the essential components, and an optional component.
  • the mode may be divided into the additive solution containing at least.
  • Each liquid constituting the polishing liquid set may be stored as a storage liquid in which the content of the liquid medium is reduced.
  • the polishing method (substrate polishing method or the like) according to this embodiment may include a polishing step of polishing a surface to be polished (surface to be polished of the substrate or the like) using the one-part polishing liquid.
  • You may provide the grinding
  • the polishing method according to the present embodiment may be a method for polishing a substrate having an insulating material and silicon nitride.
  • the one-part polishing liquid or a slurry and an additive liquid in the polishing liquid set are mixed.
  • a polishing step of selectively polishing the insulating material with respect to silicon nitride may be provided using the polishing liquid obtained in this manner.
  • the base may have, for example, a member containing an insulating material and a member containing silicon nitride.
  • the polishing method according to the present embodiment may be a method for polishing a substrate having an insulating material and polysilicon.
  • the one-part polishing liquid or the slurry and additive liquid in the polishing liquid set are used. You may provide the grinding
  • the base may have, for example, a member containing an insulating material and a member containing polysilicon.
  • “Selectively polishing material A with respect to material B” means that the polishing rate of material A is higher than the polishing rate of material B under the same polishing conditions. More specifically, for example, the material A is polished at a polishing rate ratio of the polishing rate of the material A to the polishing rate of the material B of 70 or more.
  • the polishing liquid is supplied between the material to be polished and the polishing pad in a state where the material to be polished of the substrate having the material to be polished is pressed against the polishing pad of the polishing platen, and the substrate and the polishing are performed
  • the surface to be polished is polished by moving the surface plate relatively.
  • at least a part of the material to be polished is removed by polishing.
  • Examples of the substrate to be polished include a substrate to be polished.
  • Examples of the substrate to be polished include a substrate in which a material to be polished is formed on a substrate related to semiconductor element manufacturing (for example, a semiconductor substrate on which an STI pattern, a gate pattern, a wiring pattern, etc. are formed).
  • Examples of materials to be polished include insulating materials such as silicon oxide; stopper materials such as polysilicon and silicon nitride.
  • the material to be polished may be a single material or a plurality of materials. When a plurality of materials are exposed on the surface to be polished, they can be regarded as materials to be polished.
  • the material to be polished may be in the form of a film (film to be polished), and may be a silicon oxide film, a polysilicon film, a silicon nitride film, or the like.
  • the polishing liquid according to this embodiment is preferably used for polishing a surface to be polished containing silicon oxide.
  • a stopper polishing stop layer disposed under the insulating material, and a substrate (semiconductor substrate or the like) disposed under the stopper
  • the insulating material can be polished.
  • the stopper material constituting the stopper is a material whose polishing rate is lower than that of the insulating material, and polysilicon, silicon nitride and the like are preferable.
  • the insulating material can be prevented from being excessively polished, so that the flatness of the insulating material after polishing can be improved.
  • Examples of a method for producing a material to be polished by the polishing liquid according to this embodiment include a low pressure CVD method, a quasi-atmospheric pressure CVD method, a plasma CVD method, and other CVD methods; Etc.
  • polishing method for example, a substrate having an insulating material formed on a semiconductor substrate
  • a polishing apparatus a general polishing apparatus having a holder capable of holding a substrate having a surface to be polished and a polishing surface plate to which a polishing pad can be attached can be used.
  • a motor capable of changing the rotation speed.
  • a polishing apparatus for example, a polishing apparatus: Reflexion manufactured by APPLIED MATERIALS can be used.
  • polishing pad general nonwoven fabric, foam, non-foam, etc.
  • the material of the polishing pad is polyurethane, acrylic resin, polyester, acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly-4-methylpentene, cellulose, cellulose ester, polyamide (for example, nylon (trade name)) And aramid), polyimide, polyimide amide, polysiloxane copolymer, oxirane compound, phenol resin, polystyrene, polycarbonate, epoxy resin and the like.
  • the material of the polishing pad is preferably at least one selected from the group consisting of foamed polyurethane and non-foamed polyurethane, particularly from the viewpoint of further improving the polishing rate and flatness. It is preferable that the polishing pad is grooved so that the polishing liquid accumulates.
  • the upper limit of the rotation speed of the polishing platen is preferably 200 min ⁇ 1 or less so that the substrate does not pop out, and the upper limit of the polishing pressure (working load) applied to the substrate causes polishing flaws. From the viewpoint of sufficiently suppressing this, 100 kPa or less is preferable.
  • limiting in this supply amount it is preferable that the surface of a polishing pad is always covered with polishing liquid.
  • the substrate after polishing is preferably washed well under running water to remove particles adhering to the substrate.
  • dilute hydrofluoric acid or ammonia water may be used in addition to pure water, and a brush may be used in combination to increase cleaning efficiency.
  • the polishing liquid, the polishing liquid set and the polishing method according to this embodiment can be suitably used for forming STI.
  • the lower limit of the polishing rate ratio of the insulating material (for example, silicon oxide) to the stopper material (for example, silicon nitride) is 70 or more. If the polishing rate ratio is less than 70, the polishing rate of the insulating material relative to the polishing rate of the stopper material is small, and it tends to be difficult to stop polishing at a predetermined position when forming the STI. On the other hand, if the polishing rate ratio is 70 or more, it is easy to stop polishing, which is more suitable for formation of STI.
  • the lower limit of the polishing rate of the insulating material is preferably 70 nm / min or more, more preferably 100 nm / min or more, and further preferably 130 nm / min or more.
  • the upper limit of the polishing rate of the stopper material is preferably less than 3 nm / min, more preferably 2.5 / min nm or less, and even more preferably 2 nm / min or less.
  • the polishing liquid, the polishing liquid set and the polishing method according to this embodiment can also be used for polishing a premetal insulating material.
  • a premetal insulating material for example, phosphorus-silicate glass or boron-phosphorus-silicate glass is used in addition to silicon oxide, and silicon oxyfluoride, fluorinated amorphous carbon, and the like can also be used.
  • the polishing liquid, the polishing liquid set, and the polishing method according to this embodiment can be applied to materials other than insulating materials such as silicon oxide.
  • materials include high dielectric constant materials such as Hf-based, Ti-based, and Ta-based oxides; semiconductor materials such as silicon, amorphous silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, and organic semiconductors; GeSbTe Inorganic conductive materials such as ITO; Polymer resins such as polyimides, polybenzoxazoles, acrylics, epoxies, and phenols.
  • the polishing liquid, the polishing liquid set, and the polishing method according to this embodiment are not only film-like objects to be polished, but also various types composed of glass, silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, sapphire, plastic, and the like. It can also be applied to substrates.
  • the polishing liquid, the polishing liquid set, and the polishing method according to the present embodiment are not only for manufacturing semiconductor elements, but also for image display devices such as TFTs and organic ELs; optical parts such as photomasks, lenses, prisms, optical fibers, and single crystal scintillators Optical elements such as optical switching elements and optical waveguides; light emitting elements such as solid-state lasers and blue laser LEDs; and magnetic storage devices such as magnetic disks and magnetic heads.
  • ⁇ Synthesis of hydroxides of tetravalent metal elements 350 g of Ce (NH 4 ) 2 (NO 3 ) 6 50% by mass aqueous solution (manufactured by Nippon Chemical Industry Co., Ltd., trade name: CAN50 liquid) was mixed with 7825 g of pure water to obtain a solution. Next, while stirring this solution, 750 g of an imidazole aqueous solution (10 mass% aqueous solution, 1.47 mol / L) was added dropwise at a mixing rate of 5 mL / min to obtain a precipitate containing cerium hydroxide. The synthesis of cerium hydroxide was performed at a temperature of 25 ° C. and a stirring speed of 400 min ⁇ 1 . Stirring was carried out using a three-blade pitch paddle with a total blade length of 5 cm.
  • the obtained precipitate (precipitate containing cerium hydroxide) was centrifuged (4000 min ⁇ 1 , 5 minutes) and then subjected to solid-liquid separation by removing the liquid phase by decantation. After mixing 10 g of particles obtained by solid-liquid separation and 990 g of water, the particles are dispersed in water using an ultrasonic cleaner, and cerium hydroxide containing abrasive grains containing cerium hydroxide A slurry (particle content: 1.0 mass%) was prepared.
  • the measuring method is as follows. First, about 1 mL of a measurement sample (cerium hydroxide slurry, aqueous dispersion) containing 1.0 mass% abrasive grains was placed in a 1 cm square cell, and the cell was placed in N5.
  • the refractive index of the measurement sample information of N5 software was set to 1.333, the viscosity was set to 0.887 mPa ⁇ s, the measurement was performed at 25 ° C., and the value displayed as the Unimodal Size Mean was read.
  • the abrasive grains contained in the cerium hydroxide slurry contained at least some particles having nitrate ions bonded to the cerium element. Moreover, since the particle
  • Example 2 Except having changed content of each component except an abrasive grain and a pH stabilizer, it is the same as Example 1, 0.05 mass% of abrasive grains containing cerium hydroxide, and 0.5 mass of polyethylene glycol %, A polishing slurry for CMP having a pH of 6.0 containing 0.03% by mass of an anionic branched polymer and 0.002% by mass of diallyldimethylammonium chloride polymer.
  • Example 3 Except that trishydroxymethylaminomethane was used as a pH adjuster, the same manner as in Example 2, 0.05% by mass of abrasive grains containing cerium hydroxide, 0.5% by mass of polyethylene glycol, anionic A polishing slurry for CMP having a pH of 5.8 containing 0.03% by mass of this branched polymer and 0.002% by mass of diallyldimethylammonium chloride polymer was prepared.
  • Example 4 Except that the molecular weight of the polyethylene glycol and the content of the pH adjuster were changed, 0.05% by weight of abrasive grains containing cerium hydroxide, polyethylene glycol [first additive (polyethylene Alkylene glycol), manufactured by Lion Corporation, trade name: PEG # 600, weight average molecular weight: 600] is 0.5% by mass, anionic branched polymer is 0.03% by mass, and diallyldimethylammonium chloride polymer. A polishing slurry for CMP having a pH of 6.0 containing 0.002% by mass was prepared.
  • first additive polyethylene Alkylene glycol
  • PEG # 600 weight average molecular weight: 600
  • anionic branched polymer is 0.03% by mass
  • diallyldimethylammonium chloride polymer A polishing slurry for CMP having a pH of 6.0 containing 0.002% by mass was prepared.
  • Example 5 Except that the content of the anionic polymer, the molecular weight of the cationic polymer, and the content of the pH adjuster were changed, the abrasive grains containing cerium hydroxide were added in the same manner as in Example 3 to 0.05. % By weight, 0.5% by weight of polyethylene glycol, 0.02% by weight of anionic branched polymer, diallyldimethylammonium chloride polymer [third additive (cationic polymer), manufactured by Senka Corporation, A polishing slurry for CMP having a pH of 6.5 containing 0.002% by mass of trade name: UNISENSE FPA101L, weight average molecular weight: 20000] was prepared.
  • Example 6 Except for changing the content of the cationic polymer, in the same manner as in Example 5, 0.05% by mass of abrasive grains containing cerium hydroxide, 0.5% by mass of polyethylene glycol, anionic branch 0.02% by mass of type polymer, 0.003 mass of diallyldimethylammonium chloride polymer [third additive (cationic polymer), manufactured by Senka Co., Ltd., trade name: Unisense FPA101L, weight average molecular weight: 20000] A polishing slurry for CMP having a pH of 6.5 was prepared.
  • Example 1 Except having changed the kind of 1st additive, it is the same as that of Example 2, 0.05 mass% of abrasive grains containing cerium hydroxide, polyglycerin [manufactured by Sakamoto Pharmaceutical Co., Ltd., trade name: poly CMP of pH 6.0 containing 0.5% by mass of glycerin # 750, weight average molecular weight: 750], 0.03% by mass of anionic branched polymer, and 0.002% by mass of diallyldimethylammonium chloride polymer. A polishing liquid was prepared.
  • Example 2 Except having changed the kind of 1st additive, and content of pH adjuster, it carried out similarly to Example 2, 0.05 mass% of abrasive grains containing a cerium hydroxide, ethylene oxide (EO of bisphenol A) (EO) ) 0.5% by mass of an adduct [manufactured by Nippon Emulsifier Co., Ltd., trade name: BAP4-30H glycol, weight average molecular weight: 1500], 0.03% by mass of an anionic branched polymer, diallyldimethylammonium chloride heavy A polishing slurry for CMP having a pH of 5.8 containing 0.002% by mass of coalescence was prepared.
  • EO ethylene oxide
  • EO ethylene oxide
  • Example 3 0.05% by mass of abrasive grains containing cerium hydroxide, polyoxyethylene styrenated phenyl ether, except that the type of the first additive and the content of the pH adjuster were changed, as in Example 2. 0.5% by mass [trade name: Emulgen A-500, weight average molecular weight: 3500] manufactured by Kao Corporation, 0.03% by mass of anionic branched polymer, and 0.02% of diallyldimethylammonium chloride polymer. A polishing slurry for CMP having a pH of 6.1 containing 002% by mass was prepared.
  • Example 4 Except not using the second additive and changing the content of the pH adjuster, the same manner as in Example 2, 0.05% by weight of abrasive grains containing cerium hydroxide, and 0.1% of polyethylene glycol. A polishing slurry for CMP having a pH of 6.0 containing 5% by mass and 0.002% by mass of diallyldimethylammonium chloride polymer was prepared.
  • Example 5 Except not using the third additive, the same manner as in Example 2, 0.05% by weight of abrasive grains containing cerium hydroxide, 0.5% by weight of polyethylene glycol, an anionic branched polymer A polishing slurry for CMP having a pH of 5.9 containing 0.03% by mass of was prepared.
  • Non-branched anionic polymer (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Hightenol NF-0825, polyoxyethylene styrenated phenyl ether ammonium sulfate salt) 0.0025% by mass was used as the second additive.
  • the third additive was not used and the content of the pH adjuster was changed, 0.05% by weight of abrasive grains containing cerium hydroxide, polyethylene
  • a polishing slurry for CMP having a pH of 6.0 containing 0.5% by mass of glycol and 0.0025% by mass of a non-branched anionic polymer was prepared.
  • abrasive grain size measurement The average particle size of abrasive grains (abrasive grains containing cerium hydroxide) in the CMP polishing liquid was evaluated under the following conditions. Measurement temperature: 25 ⁇ 5 ° C Measuring device: Beckman Coulter, product name: N5 Measuring method: About 1 mL of the polishing slurry for CMP was placed in a 1 cm square measuring cell, and the cell was placed in N5. Measurement was performed with the refractive index of the measurement sample information in N5 software set to 1.333 and the viscosity set to 0.887 mPa ⁇ s, and the value displayed as Unimodal Size Mean was read.
  • Polishing equipment Reflexion (manufactured by APPLIED MATERIALS) Polishing liquid flow rate for CMP: 200 mL / min Substrate to be polished: wafer without pattern and pattern wafer described below (in Comparative Examples 5 and 6, pattern wafer was not polished) Polishing pad: foamed polyurethane resin having closed cells (ROHM AND HAAS ELECTRONIC MATERIALS CMP INC., Model number IC1010 A6), Shore D hardness: 60 Polishing pressure: 16.5 kPa (2.4 psi) Relative speed between substrate to be polished and polishing surface plate: 85 m / min Polishing time: Blanket wafer was polished for 1 minute.
  • Polishing pad foamed polyurethane resin having closed cells (ROHM AND HAAS ELECTRONIC MATERIALS CMP INC., Model number IC1010 A6), Shore D hardness: 60 Polishing pressure: 16.5 kPa (2.4 psi) Relative speed between substrate to be polished and polish
  • the pattern wafer was polished until the silicon nitride film as a stopper film was exposed. Further, the degree of progress of dishing was confirmed by grinding for another 20 seconds after the silicon nitride film was exposed. Wafer cleaning: After CMP, the wafer was cleaned with water while applying ultrasonic waves, and then dried with a spin dryer.
  • a substrate to be polished having a silicon oxide film having a thickness of 1 ⁇ m formed by plasma CVD on a silicon substrate, and silicon nitride having a thickness of 0.2 ⁇ m formed by CVD As a blanket wafer on which no pattern is formed, a substrate to be polished having a silicon oxide film having a thickness of 1 ⁇ m formed by plasma CVD on a silicon substrate, and silicon nitride having a thickness of 0.2 ⁇ m formed by CVD A substrate to be polished having a film (Si 3 N 4 film) on a silicon substrate was used.
  • a pattern wafer on which a simulated pattern was formed As a pattern wafer on which a simulated pattern was formed, a 764 wafer (trade name, diameter: 300 mm) manufactured by SEMATECH was used. In the patterned wafer, a silicon nitride film is laminated on a silicon substrate as a stopper film, and then a trench is formed in an exposure process, and a silicon oxide as an insulating film is formed on the silicon substrate and the silicon nitride film so as to fill the silicon nitride film and the trench. It was a wafer obtained by laminating a film (SiO 2 film). The silicon oxide film was formed by Applied Producer HARP (High Aspect Ratio Process).
  • the pattern wafer a wafer having a line (convex portion) & space (concave portion) having a pitch of 1000 ⁇ m, 200 ⁇ m, and 100 ⁇ m and a convex pattern density of 50% was used.
  • the line & space is a simulated pattern in which an active portion masked with a silicon nitride film that is a convex portion and a trench portion that is formed with a groove that is a concave portion are alternately arranged.
  • the line and space has a pitch of 100 ⁇ m means that the total width of the line portion and the space portion is 100 ⁇ m.
  • the line and space is 100 ⁇ m pitch and the convex pattern density is 50%” means a pattern in which convex width: 50 ⁇ m and concave width: 50 ⁇ m are alternately arranged.
  • the film thickness of the silicon oxide film was 480 nm on both the silicon substrate and the silicon nitride film. Specifically, as shown in FIG. 3, the thickness of the silicon nitride film 2 on the silicon substrate 1 is 110 nm, the thickness of the convex portion of the silicon oxide film 3 is 480 nm, and the concave portion of the silicon oxide film 3 The thickness of the silicon oxide film 3 was 310 nm (trench depth 200 nm + silicon nitride film 2 thickness 110 nm).
  • the remaining step is 100 nm or less by polishing the wafer with a known CMP polishing liquid having self-stopping properties (a characteristic that the polishing rate decreases when the remaining step of the simulated pattern decreases).
  • the wafer which became the state of was used.
  • a polishing liquid in which HS-8005-D4 manufactured by Hitachi Chemical Co., Ltd., HS-7303GP manufactured by Hitachi Chemical Co., Ltd., and water are mixed at a ratio of 2: 1.2: 6.8 is used.
  • a wafer in a state where the film thickness of the convex silicon oxide film in the 1000 ⁇ m pitch 50% density pattern was polished to 130 nm was used.
  • polishing rate of the film to be polished (silicon oxide film and silicon nitride film) (silicon oxide film polishing rate: SiO 2 RR and silicon nitride film polishing rate: Si 3 N 4 RR) was calculated from the following formula.
  • film thickness difference of the to-be-polished film before and behind polishing was determined using an optical interference type film thickness measuring apparatus (trade name: F80, manufactured by Filmetrics).
  • the number of polishing scratches of 0.2 ⁇ m or more on the surface of the film to be polished was In both the comparative examples and the comparative examples, the number was about 0 to 3 (pieces / wafer), and the generation of polishing scratches was sufficiently suppressed.
  • Tables 1 and 2 show the measurement results obtained for the examples and comparative examples.
  • surface shows the following compound.
  • Compound 1A Polyethylene glycol
  • Compound 1B Polyglycerol
  • Compound 1C Ethylene oxide adduct of bisphenol A
  • Compound 1D Polyoxyethylene styrenated phenyl ether
  • Compound 2A Polyalkylene glycol-modified styrene-maleic acid copolymer
  • Compound 2B Polyoxyethylene Styrenated phenyl ether ammonium sulfate compound 3A: poly (diallyldimethylammonium chloride)
  • Compound 4A 1,3,5-tris (dimethylaminopropyl) hexahydro-1,3,5-triazine
  • Compound 4B Trishydroxymethylaminomethane
  • Example 1 the polishing rate ratio was 93, and the polishing rate ratio was higher than that of the comparative example. Further, in the pattern wafer evaluation, the remaining steps when the silicon nitride film is exposed are 4 nm (1000 ⁇ m pitch), 7 nm (200 ⁇ m pitch), and 6 nm (100 ⁇ m pitch), respectively. The amounts were 5 nm, 5 nm and 2 nm, respectively. In Example 1, the result that progress of dishing was suppressed was obtained, showing a high polishing rate ratio.
  • Example 2 the polishing rate ratio was 174, and the polishing rate ratio was higher than that of the comparative example.
  • the remaining steps when the silicon nitride film is exposed are 5 nm (1000 ⁇ m pitch), 14 nm (200 ⁇ m pitch), and 4 nm (100 ⁇ m pitch), respectively.
  • the amounts were 5 nm, 15 nm and 4 nm, respectively.
  • the result that progress of dishing was suppressed was obtained, showing a high polishing rate ratio.
  • Example 3 the polishing rate ratio was 118, and the polishing rate ratio was higher than that of the comparative example. Further, in the pattern wafer evaluation, the remaining steps when the silicon nitride film is exposed are 10 nm (1000 ⁇ m pitch), 16 nm (200 ⁇ m pitch), and 9 nm (100 ⁇ m pitch), respectively. The amounts were 8 nm, 15 nm and 7 nm, respectively. In Example 3, the result that progress of dishing was suppressed was obtained, showing a high polishing rate ratio.
  • Example 4 the polishing rate ratio was 117, and the polishing rate ratio was higher than that of the comparative example. Further, in the pattern wafer evaluation, the remaining steps when the silicon nitride film is exposed are 16 nm (1000 ⁇ m pitch), 17 nm (200 ⁇ m pitch), and 12 nm (100 ⁇ m pitch), respectively. The amounts were 16 nm, 19 nm, and 12 nm, respectively. In Example 4, a result in which the progress of dishing was suppressed while showing a high polishing rate ratio was obtained.
  • Example 5 the polishing rate ratio was 80, and the polishing rate ratio was higher than that of the comparative example. Further, in the pattern wafer evaluation, the remaining step amounts when the silicon nitride film is exposed are 4 nm (1000 ⁇ m pitch), 7 nm (200 ⁇ m pitch), and 5 nm (100 ⁇ m pitch), respectively. The amounts were 4 nm, 8 nm, and 4 nm, respectively. In Example 5, the result that progress of dishing was suppressed was obtained, showing a high polishing rate ratio.
  • Example 6 the polishing rate ratio was 188, and the polishing rate ratio was higher than that of the comparative example. Further, in the pattern wafer evaluation, the remaining step amount when the silicon nitride film is exposed is 2 nm (1000 ⁇ m pitch), 4 nm (200 ⁇ m pitch), and 3 nm (100 ⁇ m pitch), respectively. The amounts were 3 nm, 4 nm and 2 nm, respectively. In Example 6, the result that progress of dishing was suppressed was obtained, showing a high polishing rate ratio.
  • the polishing rate ratio was 68. Further, in the pattern wafer evaluation, the remaining steps when the silicon nitride film is exposed are 24 nm (1000 ⁇ m pitch), 24 nm (200 ⁇ m pitch), and 19 nm (100 ⁇ m pitch), respectively, and are further etched for 20 seconds. The remaining steps were 27 nm, 28 nm, and 22 nm, respectively.
  • the polishing rate ratio was 57. Further, in the pattern wafer evaluation, the remaining steps when the silicon nitride film is exposed are 29 nm (1000 ⁇ m pitch), 30 nm (200 ⁇ m pitch), and 23 nm (100 ⁇ m pitch), respectively, and are further etched for 20 seconds. The remaining steps were 47 nm, 46 nm, and 31 nm, respectively.
  • the polishing rate ratio was 45. Further, in the pattern wafer evaluation, the remaining steps when the silicon nitride film is exposed are 39 nm (1000 ⁇ m pitch), 44 nm (200 ⁇ m pitch), and 30 nm (100 ⁇ m pitch), respectively, and when further etched for 20 seconds. The remaining steps were 53 nm, 52 nm, and 43 nm, respectively.
  • the polishing rate ratio was 6. Further, in the pattern wafer evaluation, the remaining steps when the silicon nitride film is exposed are 16 nm (1000 ⁇ m pitch), 13 nm (200 ⁇ m pitch), and 7 nm (100 ⁇ m pitch), respectively, and are further etched for 20 seconds. The remaining steps were 16 nm, 11 nm, and 5 nm, respectively.
  • the insulating material can be polished at a high polishing rate, and the polishing rate of the stopper material can be sufficiently suppressed, and the polishing selectivity of the insulating material with respect to the stopper material can be improved. According to the present invention, it is possible to suppress the progress of dishing while improving the polishing selectivity of the insulating material with respect to the stopper material. Furthermore, according to the present invention, in the CMP technology for planarizing the STI insulating material, the premetal insulating material, the interlayer insulating material, etc., while suppressing the progress of dishing while improving the polishing selectivity of the insulating material with respect to the stopper material, The insulating material can also be polished with low polishing scratches.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

Abstract

L'invention concerne un liquide de polissage qui comprend : des grains abrasifs contenant un hydroxyde d'un élément métallique tétravalent, un polyalkylèneglycol, un composé macromoléculaire, un polymère cationique, et un milieu liquide. Ledit composé macromoléculaire possède une première chaîne moléculaire à laquelle est directement lié un groupe fonctionnel, et une seconde chaîne moléculaire ramifiée à partir de la première chaîne moléculaire. Ledit groupe fonctionnel contient au moins un élément choisi dans un groupe constitué d'un groupe carboxyle et d'un groupe carboxylate.
PCT/JP2017/003645 2017-02-01 2017-02-01 Liquide de polissage, ensemble de liquide de polissage, et procédé de polissage Ceased WO2018142516A1 (fr)

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JP2020026473A (ja) * 2018-08-10 2020-02-20 株式会社フジミインコーポレーテッド 研磨用組成物及びその製造方法並びに研磨方法並びに基板の製造方法
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