Polishing liquid, polishing liquid set, and polishing method

Abstract

A polishing liquid containing abrasive grains, at least one hydroxy acid component selected from the group consisting of hydroxy acids and salts thereof, and a compound Z having a hydrocarbon group which can be substituted and a polyoxyalkylene group, the value Z represented by the following general formula (1) being 20 or greater. Z = 0.1 x a x b / c … (1) [In formula (1), a represents the number of carbon atoms of the hydrocarbon group, b represents the total number of oxyalkylene groups in the compound Z, and c represents the HLB value of the compound Z.] 2 ×b / c…(1),[In formula (1), a represents the number of carbon atoms of the hydrocarbon group, b represents the total number of oxyalkylene groups in the compound Z, and c represents the HLB value of the compound Z.]

Description

TECHNICAL FIELD

[0001] The present application relates to a polishing liquid, a polishing liquid set, and a polishing method. BACKGROUND

[0002] In recent years, in the manufacturing process of semiconductor devices, the importance of processing techniques for high-density has been increasing. As one of the processing techniques, CMP (Chemical Mechanical Polishing) technique has become a necessary technique in the formation of STI (shallow trench isolation. Hereinafter, referred to as "STI"), planarization of front metal insulating material or interlayer insulating material, formation of plug or buried metal wiring, and the like in the manufacturing process of semiconductor devices.

[0003] With the high-density of semiconductor devices, a fine pattern forming technique is used to achieve high integration. As a result, the specifications required in the manufacturing process of semiconductor devices have become strict, and there has been a necessity to highly planarize a substrate having multiple insulating materials. In particular, in the CMP technique for forming STI (for example, lower STI of a semiconductor device), there is a case where a laminate having a substrate having a concave-convex pattern, a stopper layer (polishing stop layer containing a stopper layer material) disposed on the convex portion of the substrate, and an insulating material (for example, silicon oxide) disposed on the substrate and the stopper layer so as to fill the concave portion of the substrate is polished. In such polishing, the polishing of the insulating material is stopped by the stopper layer, and the polishing of the insulating material is stopped at the stage where the stopper layer is exposed. The reason for this is that it is difficult to artificially control the polishing amount of the insulating material (for example, the film thickness to be removed in the insulating film), and the degree of polishing is controlled by polishing the insulating material until the stopper layer is exposed.

[0004] In the CMP technique, after the polishing of the insulating material is stopped at the stage where the stopper layer is exposed, in order to avoid the insulating material remaining on the stopper layer, additional polishing is sometimes performed after the stopper layer is exposed. This additional polishing is referred to as "overpolishing". On the other hand, in the case where overpolishing is performed, even the insulating material other than the insulating material remaining on the stopper layer is sometimes additionally polished. As a result, a dishing (a phenomenon in which the insulating material (insulating material buried in the concave portion of the substrate) other than the insulating material remaining on the stopper layer is excessively polished) sometimes develops, and the planarity after polishing deteriorates. Therefore, in the CMP technique, it is necessary to suppress excessive dishing at the time of overpolishing.

[0005] In order to suppress excessive dishing, it is considered to use a polishing liquid in which the polishing selectivity of the insulating material with respect to the stopper layer material (the polishing speed ratio of the insulating material with respect to the stopper layer material) is high (for example, refer to Patent Literature 1 below).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-529269 SUMMARY

[0009] Technical Problem to be Solved by the Invention

[0010] However, even if a polishing liquid having high polishing selectivity of an insulating material with respect to a stopper layer material is used, excessive recesses cannot be inhibited at times. Therefore, not only the polishing selectivity of an insulating material with respect to a stopper layer material is focused on, but also it is required to inhibit excessive recesses when an insulating material is polished using a stopper layer.

[0011] An object of one aspect of the present invention is to provide a polishing liquid that can inhibit excessive recesses when an insulating material is polished using a stopper layer. Another object of the present invention is to provide a polishing liquid set for obtaining the polishing liquid. Further, another object of the present invention is to provide a polishing method using the polishing liquid or the polishing liquid set.

[0012] Means for Solving the Technical Problem

[0013] One aspect of the present invention relates to a polishing liquid containing a polishing grain, at least one hydroxy acid component selected from the group consisting of a hydroxy acid and a salt thereof, and a compound Z having a hydrocarbon group that can be substituted and a polyoxyalkylene group, the Z value represented by the following general formula (1) being 20 or more.

[0014] Z = 0.1 x a 2 x b / c... (1)

[0015] [In formula (1), a represents the number of carbon atoms of the hydrocarbon group, b represents the total number of oxyalkylene groups in the compound Z, and c represents the HLB value of the compound Z.]

[0016] Another aspect of the present invention relates to a polishing liquid set in which the components of the above-described polishing liquid are stored as a first liquid and a second liquid, the first liquid containing a polishing grain, and the second liquid containing a hydroxy acid component and a compound Z.

[0017] Another aspect of the present invention relates to a polishing method including a polishing step of polishing a polished surface using the above-described polishing liquid or a polishing liquid obtained by mixing the first liquid and the second liquid in the above-described polishing liquid set.

[0018] According to the above-described polishing liquid, polishing liquid set, and polishing method, when an insulating material is polished using a stopper layer, excessive recesses can be inhibited.

[0019] EFFECT OF THE INVENTION

[0020] According to the present application, when the insulating material is polished using the stopper layer, excessive recesses can be suppressed. Thus, the flatness of the substrate after over-polishing can be improved.

[0021] According to the present application, use of the polishing liquid in polishing of a polished surface containing silicon oxide can be provided. According to the present application, use of the polishing liquid in polishing of a polished surface containing silicon oxide and silicon nitride can be provided. According to the present application, use of the polishing liquid in selective polishing of silicon oxide with respect to silicon nitride can be provided. According to the present application, use of the polishing liquid in a planarization process of a substrate surface as a manufacturing technique of a semiconductor element can be provided. According to the present application, use of the polishing liquid in a planarization process of STI insulating material, pre-metal insulating material, or interlayer insulating material can be provided. According to the present application, use of the polishing liquid in formation of STI can be provided. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present application will be described in detail. However, the present application is not limited to the following embodiments.

[0023] <DEFINITIONS>

[0024] In the present specification, a numerical range represented by "~" indicates a range including the values before and after "~" as the minimum value and the maximum value, respectively. "A or more" of a numerical range means a range of A and more than A. "A or less" of a numerical range means a range of A and less than A. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range of a certain stage can be arbitrarily combined with the upper limit value or the lower limit value of the numerical range of another stage. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples. By "A or B", as long as either one of A and B is included, both can also be included. The materials exemplified in the present specification can be used alone or in combination of two or more, as long as there is no particular description. In the present specification, in the case where a plurality of substances corresponding to each component is present in the composition, the content of each component in the composition means the total amount of the plurality of substances present in the composition, as long as there is no particular description. The terms "film" and "layer" include not only a structure formed in the entire surface in a plan view, but also a structure formed in a part. The term "process" is not only an independent process, but also included in the present term as long as the desired function of the process can be achieved even if it cannot be clearly distinguished from other processes.

[0025] In the present specification, the so-called "polishing liquid" (polishing liquid, abrasive) is defined as a composition which is brought into contact with a surface to be polished at the time of polishing. The term "polishing liquid" itself does not have any limitation on the components contained in the polishing liquid. As described later, the polishing liquid according to the present embodiment contains abrasive grains. The abrasive grains are also referred to as "abrasive particles", but are referred to as "abrasive grains" in the present specification. The abrasive grains are generally solid particles, and it is considered that, at the time of polishing, the object to be removed is removed by the mechanical action (physical action) possessed by the abrasive grains and the chemical action of the abrasive grains (mainly the surface of the abrasive grains), but are not limited thereto.

[0026] <Polishing liquid and polishing liquid set>

[0027] The polishing liquid (e.g., CMP polishing liquid) according to the present embodiment contains abrasive grains, at least one hydroxy acid component selected from the group consisting of hydroxy acids and salts thereof, and a compound Z having a hydrocarbon group which can be substituted and a polyoxyalkylene group, and the Z value (parameter Z value) represented by the following general formula (1) is 20 or more.

[0028] Z = 0.1 x a 2 x b / c... (1)

[0029] [In formula (1), a represents the number of carbon atoms of the hydrocarbon group, b represents the total number of oxyalkylene groups in the compound Z, and c represents the HLB value of the compound Z.]

[0030] According to the polishing liquid according to the present embodiment, when an insulating material (except for a stopper layer material) is polished using a stopper layer, excessive dishing can be suppressed, and in particular, when silicon oxide is polished using a stopper layer containing silicon nitride, excessive dishing can be suppressed. Furthermore, according to the polishing liquid according to the present embodiment, excessive polishing of the stopper layer at the time of overpolishing can be suppressed, and the stopper layer is easily removed at the time of removing the stopper layer by etching or the like after overpolishing.

[0031] The present inventors have inferred the reasons for these effects as described below. However, the reasons are not limited to the following.

[0032] The hydroxy acid component has an effect of easily suppressing the polishing rate of the stopper layer material from becoming too high. Also, by using the hydroxy acid component, after the stopper layer is exposed, the polishing of the insulating material other than the insulating material remaining on the stopper layer (the insulating material buried in the recess of the substrate) is suppressed, whereby high planarity is easily obtained. For these reasons, the functional group (carboxyl group, carboxylate group, hydroxyl group, etc.) of the hydroxy acid component is adsorbed to the stopper layer and the insulating material to coat these materials being polished, whereby the abrasive particles are suppressed from coming into contact with the stopper layer and the insulating material. It is thus presumed that the polishing rate of the insulating material is suppressed from becoming too high by alleviating the progress of polishing based on the abrasive particles, whereby excessive recesses are suppressed.

[0033] It is presumed that the compound Z has an effect of being able to polish the insulating material at an appropriate rate by forming a protective layer on the insulating material. Also, by using the compound Z, after the stopper layer is exposed, the polishing of the insulating material other than the insulating material remaining on the stopper layer (the insulating material buried in the recess of the substrate) is suppressed, whereby high planarity is easily obtained. For these reasons, the hydrocarbon group (hydrophobic portion) and the polyoxyalkylene group (hydrophilic portion) of the compound Z are adsorbed to the insulating material to coat the insulating material, whereby the abrasive particles are suppressed from coming into contact with the insulating material. Thus, it is presumed that the polishing rate of the insulating material is suppressed from becoming too high by alleviating the progress of polishing based on the abrasive particles, whereby excessive recesses are suppressed.

[0034] As described above, it is considered that both the hydrocarbon group (hydrophobic portion) and the polyoxyalkylene group (hydrophilic portion) of the compound Z are adsorbed to the insulating material to exert a protective effect.

[0035] The oxygen atom of the polyoxyalkylene group as the hydrophilic portion is considered to be a point of adsorption to the insulating material, and thus it is presumed that the more the total number of the oxyalkylene groups in the compound Z (i.e., the more the points of adsorption), the more firmly the compound Z is adsorbed to the insulating material. Therefore, it is considered that the compound Z is less likely to be detached from the insulating material during polishing, whereby excessive recesses are suppressed.

[0036] Also, in general, a compound having a large number of carbon atoms and a compound having a small HLB value have high hydrophobicity, and thus the interaction with water molecules having high polarity is small in water, and the molecule is difficult to stabilize by hydration, and thus the surface energy of the molecule becomes high. Also, it is known that a molecule having high hydrophobicity reduces the surface energy thereof by being adsorbed to an interface. Therefore, it is considered that the more the hydrocarbon group (hydrophobic portion) of the compound Z, and the smaller the HLB value of the compound Z, the higher the interfacial energy of the compound Z, and the more easily the compound Z is adsorbed to the insulating material, and thus the effect of protecting the insulating material is high. Furthermore, it is considered that as the number of carbon atoms of the hydrocarbon group increases, the molecular weight of the compound Z becomes larger, and steric hindrance becomes large, and thus an effect of being able to protect the insulating material to which the compound Z is adsorbed from the polishing action of the abrasive particles is obtained.

[0037] For the above reasons, it is presumed that the use of the stopper layer to polish the insulating material enables an effect of suppressing excessive recesses, and the like.

[0038] The Z value of the compound Z is explained. As a result of the research by the present inventors, it was found that, when polishing an insulating material using a stopper layer, in the compound Z having a hydrocarbon group which can be substituted and a polyoxyalkylene group, adjusting the Za value represented by the following general formula (la) is effective in obtaining high planarity by suppressing excessive polishing of the insulating material to thereby suppress excessive dishing of the insulating material, and the above-mentioned Z value was found from this Za value.

[0039] Za = σ x a γ x b / c... (la)

[0040] [In formula (la), a represents the number of carbon atoms of the hydrocarbon group of the compound Z, b represents the total number of oxyalkylene groups in the compound Z, c represents the HLB value of the compound Z, and γ and σ represent weighting coefficients of the parameters.]

[0041] The step of deriving the Z value from the Za value is explained. First, the components of the Za value can be decomposed into the following two formulas.

[0042] Formula (i): a γ x b

[0043] Formula (ii): σ / c

[0044] Formula (i) is mainly set as an index relating to the number of adsorption points of the compound Z with respect to the insulating material. As to each parameter, as a result of the research, it was found that the more the number of carbon atoms a of the hydrocarbon group (hydrophobic portion) is, the greater the dishing suppression effect is, and it was found that the more the total number b of oxyalkylene groups is, the greater the dishing suppression effect is. It is considered that this is because the number of adsorption points with respect to the insulating material increases. Also, the more the parameters a and b are, the larger the steric structure of the molecule becomes, and the abrasive grains are less likely to approach the insulating material on which the compound Z is adsorbed, whereby the insulating material can be effectively protected, and therefore it is considered that the parameters a and b function in multiplication, and "a x b" formula was obtained. Here, from the research results, it was found that the number of carbon atoms a of the hydrocarbon group (hydrophobic portion) has a greater effect on the dishing suppression effect than the total number b of oxyalkylene groups, and therefore the weighting coefficient γ of the parameter a was set to 2. γ

[0045] ​The formula (ii) is mainly set as an index relating to the affinity of the compound Z with respect to water. The "HLB value" is an index indicating the affinity of a compound (surfactant, etc.) with respect to water, oil (an organic compound not soluble in water), etc., and the higher the HLB value, the higher the affinity with water, and the easier the solubility in water. As a result of the study, it was found that the smaller the HLB value (the lower the affinity with water), the greater the depression effect. There is a tendency that the smaller the HLB value (the lower the affinity with water), the higher the hydrophobicity. As described above, it is considered that a molecule having high hydrophobicity is difficult to stabilize in water by hydration, and thus the surface energy thereof becomes small by adsorption to the interface, and it is easy to adsorb to the insulating material, and thus the effect of protecting the insulating material is high. In this way, the smaller the HLB value, the easier the depression, and thus the reciprocal of the HLB value is taken, and the formula (1) of "1 / c" is obtained. Here, the HLB value is 0 to 20, and the value is small, and thus the weighting coefficient σ of the parameter c is set to 0.1 in view of the magnitude of the influence on the depression.

[0046] Further, it is considered that, with respect to the adsorption to the insulating material, the parameters set by these formula (i) and formula (ii) do not act separately but act in conjunction with each other. Therefore, it is considered that the action is multiplied rather than simply added, and thus the product of the formula (i) and formula (ii) is set, and the formula (1) of the Z value is found. Further, it is found that in the case where this Z value is 20 or more, the depression can be suppressed.

[0047] (abrasive particle)

[0048] The polishing liquid according to the present embodiment contains an abrasive particle. From the viewpoint of easily polishing the insulating material to be removed at a high polishing rate, the abrasive particle can include at least one selected from the group consisting of cerium oxide (for example, cerium dioxide (cerium (IV) oxide)), silicon dioxide, aluminum oxide, zirconium oxide, yttrium oxide, and hydroxide of a tetravalent metal element, and can include cerium oxide.

[0049] The "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 a tetravalent metal element can include anions other than the hydroxide ion (for example, nitrate ions NO3 - and sulfate ions SO4 2- ). For example, the hydroxide of a tetravalent metal element can include anions (for example, nitrate ions NO3 - and sulfate ions SO4 2- ) bonded to the tetravalent metal element. The hydroxide of a tetravalent metal element can be produced by reacting a salt of a tetravalent metal element (metal salt) with an alkali source (alkali).

[0050] From the viewpoint of easily increasing the grinding speed of the insulating material to be removed, the abrasive grains can contain cerium hydroxide (a hydroxide of tetravalent cerium). Cerium hydroxide can be produced by reacting a cerium salt with an alkaline source (alkali). Cerium hydroxide can also be produced by mixing a cerium salt with an alkaline solution (e.g., an aqueous alkaline solution). This results in extremely fine particles and easily achieves excellent reduction in grinding damage. Cerium hydroxide can be obtained by mixing a cerium salt solution (e.g., an aqueous cerium salt solution) with an alkaline solution. Examples of cerium salts include Ce(NO3)4, Ce(SO4)2, Ce(NH4)2(NO3)6, and Ce(NH4)4(SO4)4.

[0051] It is believed that, based on the manufacturing conditions of cerium hydroxide, a product containing tetravalent cerium (Ce) is formed. 4+ ), 1 to 3 hydroxide ions (OH-) - ) and 1 to 3 anions (X c- Ce(OH) a X b (In the formula, a + b × c = 4) particles (also, these particles are cerium hydroxide). It is believed that in Ce(OH) a X b In the middle, electron-withdrawing anions (X c- This enhances the reactivity of hydroxide ions, as Ce(OH)₂... a X b The increased presence of X-rays leads to a higher grinding speed. As an anion (X... c- ), can be cited as an example of NO3 - SO4 2- Etc. It is believed that particles containing cerium hydroxide can contain not only Ce(OH)₂. a X b It can also contain Ce(OH)4, CeO2, etc.

[0052] Regarding particles containing cerium hydroxide, they contain Ce(OH). a X b It is possible to detect anions (X-ray diions) by thoroughly washing particles with pure water and then using the FT-IR ATR method (Fourier transform infrared spectrophotometer attenuated total reflection method). c- The corresponding peak method can be used to confirm this. It can also be confirmed using XPS (X-ray Photoelectron Spectroscopy) to identify the anion (X). c- The existence of ).

[0053] From the viewpoint of easily increasing the polishing rate of the insulating material to be removed, the lower limit of the content of cerium oxide can be 50% by mass or more, more than 50% by mass, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, in the case where the abrasive grains contain cerium oxide, with the abrasive grains as a whole (the abrasive grains contained in the polishing liquid. The same applies hereinafter) as a reference.

[0054] From the viewpoint of easily increasing the polishing rate of the insulating material to be removed, the lower limit of the average particle diameter of the abrasive grains in the polishing liquid, or the slurry in the polishing liquid set described later, can be 16 nm or more, 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 100 nm or more, 120 nm or more, 150 nm or more, or 155 nm or more. From the viewpoint of easily suppressing damage to the surface to be polished, the upper limit of the average particle diameter of the abrasive grains can be 1050 nm or less, 1000 nm or less, 800 nm or less, 600 nm or less, 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, or 160 nm or less. From these viewpoints, the average particle diameter of the abrasive grains can be 16 to 1050 nm or 20 to 1000 nm.

[0055] The "average particle diameter" of the abrasive grains refers to the average secondary particle diameter of the abrasive grains. For example, the average particle diameter of the abrasive grains is the volume average particle diameter, and for the slurry in the polishing liquid, or the polishing liquid set described later, can be measured using a light diffraction scattering type particle size distribution meter (for example, Microtrac BEL Corp., trade name: Microtrac MT3300EXII).

[0056] From the viewpoint of easily suppressing excessive recesses and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing, the zeta potential (surface potential) of the abrasive grains in the polishing liquid can be positive (zeta potential exceeding 0 mV). From the viewpoint of easily suppressing excessive recesses and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing, the lower limit of the zeta potential of the abrasive grains can be 10 mV or more, 20 mV or more, 25 mV or more, 30 mV or more, 40 mV or more, or 50 mV or more. The upper limit of the zeta potential of the abrasive grains is not particularly limited and can be 200 mV or less. From these viewpoints, the zeta potential of the abrasive grains can be 10 to 200 mV.

[0057] The zeta potential of the abrasive grains can be measured, for example, using a dynamic light scattering type zeta potential measuring device (for example, Beckman Coulter, Inc., trade name: Delsa Nano C). The zeta potential of the abrasive grains can be adjusted using an additive. For example, by bringing a monocarboxylic acid (for example, acetic acid) into contact with the abrasive grains containing cerium oxide, abrasive grains having a positive zeta potential can be obtained.

[0058] The content of the abrasive grains can be in the following ranges based on the total mass of the polishing liquid. From the viewpoint of easily increasing the polishing rate of the insulating material to be removed, the lower limit of the content of the abrasive grains can be 0.005% by mass or more, 0.01% by mass or more, 0.02% by mass or more, 0.03% by mass or more, 0.04% by mass or more, 0.05% by mass or more, 0.07% by mass or more, 0.08% by mass or more, or 0.1% by mass or more. From the viewpoint of easily obtaining excellent dispersion stability of the abrasive grains, the upper limit of the content of the abrasive grains can be 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.3% by mass or less, 0.2% by mass or less, or 0.1% by mass or less. From these viewpoints, the content of the abrasive grains can be 0.005 to 20% by mass or 0.01 to 10% by mass.

[0059] The abrasive grains can include composite particles composed of a plurality of particles in contact with each other. For example, the abrasive grains can include composite particles including a first particle and a second particle in contact with the first particle, and can include composite particles and free particles (for example, a second particle not in contact with the first particle).

[0060] Regarding the abrasive grains, as a mode including composite particles, there can be a mode including a first particle and a second particle in contact with the first particle, the particle diameter of the second particle is smaller than the particle diameter of the first particle, and the first particle contains cerium oxide and the second particle contains a cerium compound. By using such abrasive grains, it is easy to increase the polishing rate of the insulating material (for example, silicon oxide) to be removed. Thus, as a reason for increasing the polishing rate of the insulating material, for example, the following reasons can be given. However, the reasons are not limited to the following.

[0061] That is, the first particle containing cerium oxide and having a larger particle diameter than the second particle has a stronger mechanical action (mechanical property) with respect to the insulating material than the second particle. On the other hand, the second particle containing a cerium compound and having a smaller particle diameter than the first particle has a smaller mechanical action with respect to the insulating material than the first particle, but the specific surface area (surface area per unit mass) of the entire particle is large, and thus has a stronger chemical action (chemical property) with respect to the insulating material. Thus, by combining the first particle having a strong mechanical action and the second particle having a strong chemical action, a synergistic effect of increasing the polishing rate is easily obtained.

[0062] As the cerium compound of the second particle, cerium hydroxide, cerium oxide, and the like can be given. As the cerium compound of the second particle, a compound different from cerium oxide can be used. From the viewpoint of easily increasing the polishing rate of the insulating material to be removed, the cerium compound can include cerium hydroxide.

[0063] The particle diameter of the second particles can be smaller than the particle diameter of the first particles. The size relationship of the particle diameters of the first particles and the second particles can be determined from a SEM image or the like of the composite particles. Generally, the surface area per unit mass is large in a particle with a small particle diameter compared to a particle with a large particle diameter, and thus the reactivity is high. On the other hand, the mechanical action (mechanical polishing power) of a particle with a small particle diameter is smaller than that of a particle with a large particle diameter. However, in the present embodiment, even in the case where the particle diameter of the second particles is smaller than the particle diameter of the first particles, the synergistic effect of the first particles and the second particles can be exhibited, and excellent reactivity and mechanical action can be easily balanced.

[0064] The lower limit of the particle diameter of the first particles can be 15 nm or more, 25 nm or more, 35 nm or more, 40 nm or more, 50 nm or more, 80 nm or more, or 100 nm or more from the viewpoint of easily increasing the polishing rate of the insulating material to be removed. The upper limit of the particle diameter of the first particles can be 1000 nm or less, 800 nm or less, 600 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, or 150 nm or less from the viewpoint of easily increasing the dispersibility of the abrasive particles and easily suppressing damage to the surface to be polished. The particle diameter of the first particles can be 15 nm to 1000 nm from these viewpoints. The average particle diameter (average secondary particle diameter) of the first particles can be within the above range.

[0065] The lower limit of the particle diameter of the second particles can be 1 nm or more, 2 nm or more, or 3 nm or more from the viewpoint of easily increasing the polishing rate of the insulating material to be removed. The upper limit of the particle diameter of the second particles can be 50 nm or less, 30 nm or less, 25 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less from the viewpoint of easily increasing the dispersibility of the abrasive particles and easily suppressing damage to the surface to be polished. The particle diameter of the second particles can be 1 nm to 50 nm from these viewpoints. The average particle diameter (average secondary particle diameter) of the second particles can be within the above range.

[0066] The composite particles containing the first particles and the second particles can be obtained by bringing the first particles and the second particles into contact using a homogenizer, a nano-mill, a ball mill, a bead mill, an ultrasonic processor, or the like, bringing the first particles and the second particles into contact in a state where the content of the particles is small, or the like. The first particles can have a negative zeta potential. The second particles can have a positive zeta potential.

[0067] (Additive)

[0068] The polishing liquid according to the present embodiment contains an additive. Here, the "additive" refers to a substance contained in the polishing liquid other than the abrasive particles and the liquid medium.

[0069] [Hydroxy Acid Component]

[0070] The polishing liquid according to the present embodiment contains at least one hydroxy acid component selected from the group consisting of hydroxy acids and salts thereof. A hydroxy acid is a compound having one or more carboxyl groups and one or more hydroxyl groups. In a salt of a hydroxy acid, the hydrogen atom of at least one carboxyl group is replaced with a metal atom (e.g., an alkali metal atom). As the salt of a hydroxy acid, a sodium salt, a potassium salt, and the like can be given. The "hydroxyl group" does not include the "-OH" in the carboxyl group. The "hydroxyl group" can be either of an alcoholic hydroxyl group and a phenolic hydroxyl group. The hydroxy acid component can not have a phenolic hydroxyl group.

[0071] The total number of carboxyl groups and carboxylate groups (the total number of carboxyl groups and carboxylate groups in one molecule) in the hydroxy acid component can be within the following range, from the viewpoint of easily inhibiting excessive recesses and from the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of overpolishing. The total number of carboxyl groups and carboxylate groups can be one or more. The total number of carboxyl groups and carboxylate groups can be three or less or two or less. From these viewpoints, the total number of carboxyl groups and carboxylate groups can be one to three or one to two, or can be one.

[0072] The number of hydroxyl groups (the number of hydroxyl groups in one molecule) in the hydroxy acid component can be within the following range, from the viewpoint of easily inhibiting excessive recesses and from the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of overpolishing. The number of hydroxyl groups can be one or more, two or more, or three or more. The number of hydroxyl groups can be three or less or two or less. From these viewpoints, the number of hydroxyl groups can be one to three or one to two, or can be two.

[0073] The hydroxy acid component can include a compound having one carboxyl group and one hydroxyl group, can include a compound having one carboxyl group and two hydroxyl groups, and can include a compound having one carboxyl group and three hydroxyl groups.

[0074] As the hydroxy acid component, glycolic acid, glyceric acid, lactic acid (e.g., DL-lactic acid), 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butyric acid, N,N-bis(2-hydroxyethyl)glycine, N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine, N,N-dihydroxyethylglycine (bicine), tris(hydroxymethyl)methylglycine (tricine), tyrosine, serine, salts of these, and the like can be given. From the viewpoint of easily inhibiting excessive recesses and from the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of overpolishing, the hydroxy acid component can include at least one selected from the group consisting of lactic acid, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butyric acid, tris(hydroxymethyl)methylglycine, and salts of these.

[0075] From the viewpoint of easily obtaining excellent dispersion stability of the abrasive grains, the viewpoint of easily suppressing excessive dishing, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of over-polishing, the hydroxy acid component can include at least one selected from the group consisting of aliphatic hydroxy acids and salts thereof. The hydroxy acid component can include at least one selected from the group consisting of hydroxy acids including a nitrogen atom and salts thereof, and can include at least one selected from the group consisting of hydroxy acids not including a nitrogen atom and salts thereof.

[0076] The content of the hydroxy acid component can be within the following range based on the total mass of the polishing liquid. From the viewpoint of easily suppressing excessive dishing, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of over-polishing, the lower limit of the content of the hydroxy acid component can be 0.01 mass% or more, 0.03 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.2 mass% or more, 0.3 mass% or more, or 0.4 mass% or more. From the viewpoint of easily obtaining an appropriate polishing rate of the insulating material, the viewpoint of easily suppressing excessive dishing, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of over-polishing, the upper limit of the content of the hydroxy acid component can be 5.0 mass% or less, 2.0 mass% or less, 1.0 mass% or less, 0.8 mass% or less, 0.6 mass% or less, 0.5 mass% or less, or 0.4 mass% or less. From these viewpoints, the content of the hydroxy acid component can be 0.01 to 5.0 mass% or 0.01 to 1.0 mass%.

[0077] The content of the hydroxy acid component can be within the following range with respect to 100 parts by mass of the abrasive grains. From the viewpoint of easily suppressing excessive dishing, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of over-polishing, the lower limit of the content of the hydroxy acid component can be 10 parts by mass or more, 50 parts by mass or more, 100 parts by mass or more, 150 parts by mass or more, 200 parts by mass or more, 250 parts by mass or more, 300 parts by mass or more, 350 parts by mass or more, or 400 parts by mass or more. From the viewpoint of easily obtaining an appropriate polishing rate of the insulating material, the viewpoint of easily suppressing excessive dishing, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of over-polishing, the upper limit of the content of the hydroxy acid component can be 1000 parts by mass or less, 800 parts by mass or less, 600 parts by mass or less, 550 parts by mass or less, 500 parts by mass or less, 450 parts by mass or less, or 400 parts by mass or less. From these viewpoints, the content of the hydroxy acid component can be 10 to 1000 parts by mass or 100 to 500 parts by mass.

[0078] [Compound Z]

[0079] The polishing liquid according to the present embodiment contains a compound (a compound other than a hydroxy acid component) having a hydrocarbon group x that can be substituted and a polyoxyalkylene group as the compound Z. In the compound Z, the Z value represented by the following general formula (1) is 20 or more.

[0080] Z = 0.1 x a 2 x b / c... (1)

[0081] [In formula (1), a represents the number of carbon atoms of the hydrocarbon group x of the compound Z, b represents the total number of oxyalkylene groups in the compound Z, and c represents the HLB value of the compound Z.]

[0082] As the hydrocarbon group x, a monovalent hydrocarbon group such as an alkyl group or an aryl group can be used. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of overpolishing, the hydrocarbon group x can include at least one selected from the group consisting of an alkyl group and an aryl group. The "alkyl group" can be any one of a straight chain, a branched chain, or a cyclic. As the alkyl group, decyl group, lauryl group, cetyl group, stearyl group, docosyl group, and the like can be given. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of overpolishing, the alkyl group can include a saturated alkyl group. As the aryl group, phenyl group, substituted phenyl group (styrylated phenyl group, distyrylated phenyl group, tristyrylated phenyl group, and the like), polycyclic phenyl group (naphthyl group and the like), and the like can be given. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of overpolishing, the number of hydrocarbon groups x in the compound Z can be 1, 2, or 3.

[0083] The hydrocarbon group x can be substituted or unsubstituted. In the substituted hydrocarbon group, at least one hydrogen atom of the hydrocarbon group is substituted with a substituent, and can be a group including a heteroatom such as a nitrogen atom (for example, alkylamino group). As the substituent, a hydroxyl group, an alkoxy group, a carboxyl group, a carboxylate group, an amino group, and the like can be given. The hydrocarbon group x does not include a hydrocarbon portion constituting the oxyalkylene group in the polyoxyalkylene group.

[0084] The hydrocarbon group x can be directly bonded to the polyoxyalkylene group or can be bonded to the polyoxyalkylene group via another atom. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of overpolishing, the compound Z can include a compound having an oxygen atom to which the hydrocarbon group x and the polyoxyalkylene group are bonded, or can include a compound having a nitrogen atom to which the hydrocarbon group x and the polyoxyalkylene group are bonded.

[0085] The lower limit of the number of carbon atoms of the hydrocarbon group x is 1 or more, and from the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing, it can be 3 or more, 5 or more, 8 or more, 10 or more, 12 or more, 15 or more, 18 or more, 20 or more, 21 or more, 24 or more, 27 or more, or 30 or more. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing, the upper limit of the number of carbon atoms of the hydrocarbon group x can be 50 or less, 40 or less, 35 or less, 30 or less, 27 or less, 24 or less, 21 or less, or 18 or less. The number of carbon atoms of the hydrocarbon group x can be 1 to 50, 10 to 40, or 12 to 30. In the case where the compound Z has a plurality of hydrocarbon groups x, the number of carbon atoms of the hydrocarbon group x (a of formula (1)) represents the total number of carbon atoms of the hydrocarbon groups x included in the compound Z.

[0086] As the polyoxyalkylene group, polyoxyethylene, polyoxypropylene, and the like can be given. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing, the polyoxyalkylene group can include polyoxyethylene. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing, the number of polyoxyalkylene groups in the compound Z can be 1, 2, or 3.

[0087] The total number of oxyalkylene groups in the compound Z (b of formula (1)) is the total number of oxyalkylene groups (oxyethylene, oxypropylene, and the like) included in the compound Z. The lower limit of the total number of oxyalkylene groups is 2 or more, and from the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing, it can be 3 or more, 5 or more, 8 or more, 10 or more, 12 or more, 14 or more, 15 or more, 20 or more, 23 or more, 25 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, or 80 or more. From the viewpoint of easily inhibiting excessive recesses and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing, the upper limit of the total number of oxyalkylene groups can be 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, 50 or less, 40 or less, 30 or less, 25 or less, 23 or less, 20 or less, 15 or less, or 14 or less. From these viewpoints, the total number of oxyalkylene groups can be 2 to 100, 10 to 80, or 14 to 80.

[0088] The HLB value of the compound Z is an index indicating the affinity of the compound (surfactant, etc.) with respect to water, oil (an organic compound that is not soluble in water), and the like, and can be calculated according to the Griffin method and from the following formula. The HLB value is a value of 0 to 20.0. The more the HLB value approaches 0, the higher the lipophilicity, and the more the HLB value approaches 20.0, the higher the hydrophilicity. That is, the higher the HLB value, the more easily soluble in water.

[0089] HLB value = 20.0 x [(sum of formula weight of polyoxyalkylene) / (molecular weight of compound)]

[0090] The lower limit of the HLB value of the compound Z can be 8.0 or more, 9.0 or more, 10.0 or more, 11.0 or more, 12.0 or more, 13.0 or more, 14.0 or more, 14.5 or more, 15.0 or more, 16.0 or more, 16.5 or more, 17.0 or more, 18.0 or more, or 18.5 or more, from the viewpoint of excellent solubility in water, the viewpoint of easily inhibiting excessive recess, and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing. The upper limit of the HLB value of the compound Z can be 19.0 or less, 18.5 or less, 18.0 or less, 17.0 or less, 16.5 or less, 16.0 or less, 15.0 or less, or 14.5 or less, from the viewpoint of easily inhibiting excessive recess and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing. The HLB value of the compound Z can be 8.0 to 20.0, from these viewpoints.

[0091] The lower limit of the Z value can be 30 or more, 40 or more, 45 or more, 50 or more, 80 or more, 90 or more, 100 or more, 120 or more, 125 or more, 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, or 380 or more, from the viewpoint of easily inhibiting excessive recess and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing. The upper limit of the Z value can be 1000 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, or 390 or less, from the viewpoint of easily obtaining an excellent polishing rate of the insulating material to be removed, the viewpoint of easily inhibiting excessive recess, and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing. The Z value can be 30 to 1000 or 40 to 1000, from these viewpoints.

[0092] The compound Z can include a compound represented by the following general formula (z1), from the viewpoint of easily inhibiting excessive recess and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing. The hydrocarbon group x of the compound represented by the general formula (z1) can be an aryl group or an aryl group having a plurality of aromatic rings, from the viewpoint of easily inhibiting excessive recess and the viewpoint of easily inhibiting excessive polishing of the stopper layer at the time of over-polishing.

[0093]

[0094] [In formula (z1), A 1 represents an alkylene group, R 1 represents a hydrocarbon group x, and n1 represents an integer of 2 or more.]

[0095] As A 1Alkylenes can be exemplified by ethylene and propylene. R 1 The hydrocarbon group x can satisfy the characteristics mentioned above for the hydrocarbon group x. n1 can be the range of the total number of oxyalkylene groups (b of formula (1)) as mentioned above.

[0096] From the viewpoint of easily suppressing excessive indentation and easily suppressing excessive wear of the stop layer during over-grinding, compound Z may comprise a compound represented by the following general formula (z2). From the viewpoint of easily suppressing excessive indentation and easily suppressing excessive wear of the stop layer during over-grinding, the hydrocarbon group x of the compound represented by general formula (z2) may be an alkyl group.

[0097]

[0098] In formula (z2), A 21 and A 22 Each independently represents an alkylene group, R 2 Let x represent a hydrocarbon group, and n21 and n22 each independently represent an integer greater than 2.

[0099] As A 21 and A 22 Alkylenes can be exemplified by ethylene and propylene. R 2 The hydrocarbon group x can satisfy the above-mentioned characteristics of hydrocarbon group x. The sum of n21 and n22 can be within the range of the total number of oxoalkylene groups (b of formula (1)) as described above.

[0100] From the viewpoint of easily suppressing excessive indentation and easily suppressing excessive abrasion of the stop layer during over-abrasion, compound Z may contain at least one selected from the group consisting of polyoxyethylene alkylamine (e.g., polyoxyethylene stearamine), polyoxyethylene styrene phenyl ether, and polyoxyethylene polycyclic phenyl ether.

[0101] From the perspective of easily suppressing excessive indentation and easily suppressing excessive abrasion of the stop layer during over-abrasion, compound Z can contain a nonionic surfactant. Ionic surfactants (anionic surfactants, cationic surfactants, amphoteric surfactants, etc.) are surfactants that ionize to become ions, while nonionic surfactants are surfactants that ionize but do not become ions.

[0102] From the viewpoint of easily suppressing excessive recesses and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing, the lower limit of the content of the compound Z can be 50% by mass or more, 70% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more, with respect to the total mass of the surfactant (the total amount of the surfactant contained in the polishing liquid). The surfactant contained in the polishing liquid can be in a manner in which the compound Z substantially constitutes the surfactant (a manner in which the content of the compound Z is substantially 100% by mass with respect to the total mass of the surfactant contained in the polishing liquid).

[0103] The lower limit of the content of the compound Z can be in the following range with respect to the total mass of the polishing liquid. From the viewpoint of easily suppressing excessive recesses and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing, the lower limit of the content of the compound Z can be 0.01% by mass or more, 0.02% by mass or more, 0.03% by mass or more, 0.04% by mass or more, or 0.05% by mass or more. From the viewpoint of easily obtaining a proper polishing rate of the insulating material, the viewpoint of easily suppressing excessive recesses, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing, the upper limit of the content of the compound Z can be 5.0% by mass or less, 2.0% by mass or less, 1.0% by mass or less, 0.8% by mass or less, 0.5% by mass or less, 0.3% by mass or less, 0.2% by mass or less, 0.1% by mass or less, 0.08% by mass or less, or 0.05% by mass or less. From these viewpoints, the content of the compound Z can be 0.01 to 5.0% by mass or 0.01 to 2.0% by mass.

[0104] The content of the compound Z can be in the following range with respect to 100 parts by mass of the abrasive grains. From the viewpoint of easily suppressing excessive recesses and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing, the lower limit of the content of the compound Z can be 1 part by mass or more, 5 parts by mass or more, 10 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, or 40 parts by mass or more. From the viewpoint of easily obtaining a proper polishing rate of the insulating material, the viewpoint of easily suppressing excessive recesses, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing, the upper limit of the content of the compound Z can be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 55 parts by mass or less, 50 parts by mass or less, 45 parts by mass or less, or 40 parts by mass or less. From these viewpoints, the content of the compound Z can be 1 to 100 parts by mass or 10 to 50 parts by mass.

[0105] The content of the compound Z can be within the following range with respect to 100 parts by mass of the hydroxy acid component. From the viewpoint of easily suppressing excessive recesses and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of over-polishing, the lower limit of the content of the compound Z can be 1 part by mass or more, 3 parts by mass or more, 5 parts by mass or more, 8 parts by mass or more, 10 parts by mass or more, 12 parts by mass or more, or 12.5 parts by mass or more. From the viewpoint of easily obtaining an appropriate polishing rate of the insulating material, the viewpoint of easily suppressing excessive recesses, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of over-polishing, the upper limit of the content of the compound Z can be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, 15 parts by mass or less, or 12.5 parts by mass or less. From these viewpoints, the content of the compound Z can be 1 to 100 parts by mass or 5 to 50 parts by mass.

[0106] [Optional additives]

[0107] The polishing liquid according to the present embodiment can contain an arbitrary additive other than the hydroxy acid component and the compound Z. As the arbitrary additive, a pH adjuster, a surfactant other than the compound Z, a water-soluble polymer, an oxidizing agent (for example, hydrogen peroxide), a dispersant (for example, a phosphoric acid-based inorganic salt), and the like can be given.

[0108] In the polishing liquid according to the present embodiment, a pH adjuster can be used to adjust the pH to a desired value. As the pH adjuster, an acid component, a base component, and the like can be given. As the acid component, amino acids such as glycine, serine, cysteine, glutamic acid, and alanine; inorganic acids; organic acids; and the like can be given. As the base component, ammonia, sodium hydroxide, tetramethylammonium hydroxide (TMAH), imidazole, alkanolamines, and the like can be given. In order to stabilize the pH, a buffer can be used. The buffer can be supplied by a buffer solution (a liquid containing a buffer). As the buffer solution, acetate buffer solutions, phthalate buffer solutions, and the like can be given.

[0109] As the surfactant other than the compound Z, polyoxyethylene (7) laurylamine, polyoxyethylene (11) isopropylphenyl phenyl ether, and the like can be given. The "water-soluble polymer" is defined as a polymer that dissolves 0.1 g or more with respect to 100 g of water. As the water-soluble polymer, polyglycerol, polyvinyl alcohol, polyalkylene glycol, and other polyhydric alcohols; cationic polymers such as acrylate having a quaternary ammonium base, polyallylamine hydrochloride, and polyethyleneimine; and the like can be given.

[0110] The polishing liquid according to the present embodiment can be one that does not substantially contain an oxidizing agent (one in which the content of the oxidizing agent is substantially 0 mass% based on the total mass of the polishing liquid). The upper limit of the content of the oxidizing agent can be 0.01 mass% or less, 0.001 mass% or less, or 0.0001 mass% or less based on the total mass of the polishing liquid. The polishing liquid according to the present embodiment can be one that does not contain at least one compound a selected from the group consisting of a branched molecule having a molecular structure in which the branching is three or more, a central atom is a nitrogen atom or a carbon atom, and three or more ethylene oxide groups are included in one molecule, and a salt thereof, and a compound including one or more functional groups that are ionized in an aqueous solution and three or more ethylene oxide groups, and a salt thereof. The upper limit of the content of the compound a can be 0.00001 mass% or less (0.1 ppm or less) or less than 0.00001 mass% based on the total mass of the polishing liquid.

[0111] (Liquid medium)

[0112] The polishing liquid according to the present embodiment can contain a liquid medium. The liquid medium is not particularly limited and can be water such as deionized water, ultrapure water, or the like. The content of the liquid medium can be the balance of the polishing liquid other than the contents of the other constituent components, and is not particularly limited.

[0113] (pH)

[0114] The lower limit of the pH of the polishing liquid according to the present embodiment can be 2.0 or more, 2.2 or more, 2.5 or more, 3.0 or more, 3.1 or more, 3.3 or more, 3.5 or more, 3.8 or more, or 4.0 or more from the viewpoint of easily obtaining excellent dispersion stability of the abrasive grains, the viewpoint of easily suppressing excessive recesses, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing. The upper limit of the pH can be 6.0 or less, 5.5 or less, 5.0 or less, less than 5.0, 4.5 or less, 4.2 or less, or 4.0 or less from the viewpoint of easily obtaining excellent dispersion stability of the abrasive grains, the viewpoint of easily suppressing excessive recesses, and the viewpoint of easily suppressing excessive polishing of the stopper layer at the time of overpolishing. The pH of the polishing liquid can be 2.0 to 6.0 or 2.5 to 4.5 from these viewpoints. The pH of the polishing liquid is defined as the pH at a liquid temperature of 25°C.

[0115] The pH of the polishing liquid can be measured using a pH meter (for example, Model PH81 (trade name) manufactured by Yokogawa Electric Corporation). For example, after 2-point calibration using standard buffers (phthalate pH buffer pH: 4.21 (25°C), neutral phosphate pH buffer pH 6.86 (25°C)), the electrode is placed in the polishing liquid, and the value after stabilization for 2 minutes or more at 25°C is measured.

[0116] (Storage method)

[0117] The polishing liquid according to the present embodiment can be stored as a single-liquid polishing liquid containing at least the abrasive grains, the hydroxyl acid component, and the compound Z, or as a multi-liquid (e.g., two-liquid) polishing liquid set in which the components of the polishing liquid are stored as a slurry (1st liquid) and an additive liquid (2nd liquid). The slurry contains at least the abrasive grains, for example. The additive liquid contains at least the hydroxyl acid component and the compound Z, for example. The hydroxyl acid component, the compound Z, and any additives can be contained in the additive liquid of the slurry and the additive liquid. The components of the polishing liquid can be stored as a polishing liquid set divided into three or more liquids.

[0118] In the polishing liquid set, the slurry and the additive liquid are mixed to produce the polishing liquid before or during polishing. The single-liquid polishing liquid can be stored as a storage liquid for a polishing liquid with a reduced content of the liquid medium, and used by diluting with the liquid medium during polishing. The polishing liquid set can be stored as a storage liquid for the slurry and a storage liquid for the additive liquid with a reduced content of the liquid medium, and used by diluting with the liquid medium during polishing.

[0119] <Polishing method>

[0120] The polishing method according to the present embodiment can include a polishing step of polishing a surface to be polished using the polishing liquid according to the present embodiment (single-liquid polishing liquid) or a polishing liquid obtained by mixing the slurry and the additive liquid of the polishing liquid set according to the present embodiment. The surface to be polished can contain silicon oxide or silicon oxide and silicon nitride.

[0121] The polishing method according to the present embodiment can be a polishing method of a substrate having an insulating material and silicon nitride, and can include a polishing step of selectively polishing the insulating material with respect to the silicon nitride using the polishing liquid according to the present embodiment (single-liquid polishing liquid) or a polishing liquid obtained by mixing the slurry and the additive liquid of the polishing liquid set according to the present embodiment. The substrate can have a member containing the insulating material and a member containing the silicon nitride, for example. "Selectively polishing material A with respect to material B" means that the polishing rate of material A is higher than that of material B under the same polishing conditions.

[0122] The polishing method according to the present embodiment can be a polishing method of a substrate having a first member containing silicon nitride, a second member containing an insulating material, and disposed on the first member. The polishing process can have a process of polishing the second member until the first member is exposed using the polishing liquid according to the present embodiment (single-liquid polishing liquid) or a polishing liquid obtained by mixing the slurry and the additive liquid in the polishing liquid set according to the present embodiment. The polishing process can have a process of polishing the first member and the second member after the first member is exposed using the polishing liquid according to the present embodiment (single-liquid polishing liquid) or a polishing liquid obtained by mixing the slurry and the additive liquid in the polishing liquid set according to the present embodiment.

[0123] In the polishing process, for example, the polishing liquid can be supplied between the polished material and the polishing pad (polishing cloth) of the polishing platform in a state where the polished material of the substrate having the polished material is pressed against the polishing pad, and the substrate is relatively moved with respect to the polishing platform to polish the polished surface of the polished material. In the polishing process, at least a part of the polished material can be removed by polishing, for example.

[0124] As the substrate to be polished, a polished substrate or the like can be given. As the polished substrate, for example, a substrate having a polished material formed on a substrate related to the manufacture of a semiconductor element (for example, a semiconductor substrate on which an STI pattern, a gate pattern, a wiring pattern, or the like is formed) can be given. As the polished material, an insulating material such as silicon oxide (except for a material corresponding to a stopper layer material); a stopper layer material such as silicon nitride; or the like can be given. The polished material can be a single material or a plurality of materials. In a case where a plurality of materials are exposed to the polished surface, these can be regarded as the polished material. The polished material can be a film (polished film) or a silicon oxide film, a silicon nitride film, or the like.

[0125] By polishing the polished material (for example, an insulating material such as silicon oxide) formed on such a substrate with the polishing liquid, the excess part can be removed, and thus the surface of the polished material can be smoothed to obtain a surface that is smooth over the entire surface of the polished material. The polishing liquid according to the present embodiment can be used to polish a polished surface containing silicon oxide or a polished surface containing silicon oxide and silicon nitride.

[0126] In the present embodiment, the insulating material having at least silicon oxide on the surface, the stopper layer (polishing stop layer) disposed on the lower layer of the insulating material, and the substrate (semiconductor substrate or the like) disposed below the stopper layer in the substrate can be polished. The stopper layer material constituting the stopper layer can be silicon nitride as a material having a lower polishing rate than the insulating material.

[0127] As a method for producing a material to be polished by the polishing liquid according to the present embodiment, a CVD method such as a low-pressure CVD method, an atmospheric pressure CVD method, or a plasma CVD method; a spin coating method in which a liquid raw material is coated on a rotating substrate; or the like can be mentioned.

[0128] Hereinafter, as an example of a substrate (for example, a substrate having an insulating material formed on a semiconductor substrate), a polishing method will be described. In the polishing method according to the present embodiment, as a polishing device, a general polishing device having a holder capable of holding a substrate having a polishing surface and a polishing stage capable of attaching a polishing pad can be used. Motors or the like capable of changing the rotation speed are installed on the holder and the polishing stage, respectively. As the polishing device, for example, a polishing device manufactured by APPLIED MATERIALS, INC., MIRRA, can be used.

[0129] As the polishing pad, a general nonwoven fabric, a foam, a non-foam, or the like can be used. As the material of the polishing pad, a resin such as polyurethane, an acrylic resin, a polyester, an acrylic-ester copolymer, polytetrafluoroethylene, polypropylene, polyethylene, poly 4-methyl pentene, cellulose, cellulose ester, a polyamide (for example, nylon (trade name) and aramid), a polyimide, a polyimide amide, a polysiloxane copolymer, an oxirane compound, a phenol resin, polystyrene, polycarbonate, an epoxy resin, or the like can be mentioned. From the viewpoint of easily obtaining an excellent polishing rate and planarity, as the material of the polishing pad, at least one selected from the group consisting of a foamed polyurethane and a non-foamed polyurethane can be used. The polishing pad can be subjected to groove processing such as storage of the polishing liquid.

[0130] The polishing conditions are not limited, and the upper limit of the rotation speed of the polishing stage can be 200 rpm (rpm = min -1 ) or less so that the substrate does not fly out. From the viewpoint of easily sufficiently suppressing generation of polishing damage, the upper limit of the polishing pressure (processing load) applied to the substrate can be 15 psi (103 kPa) or less. During polishing, a pump or the like can be used to continuously supply the polishing liquid to the polishing pad. The amount of the polishing liquid supplied is not limited, but the surface of the polishing pad can be covered with the polishing liquid at all times.

[0131] The substrate after polishing can be thoroughly washed in running water to remove particles adhering to the substrate. At the time of washing, dilute hydrofluoric acid or ammonia water can be used in addition to pure water, and a brush can be used to improve the washing efficiency. After washing, the substrate can be dried by removing water droplets adhering to the substrate using a spin dryer or the like.

[0132] The present embodiment can also be used for polishing of a pre-metal insulating material. As the pre-metal insulating material, silicon oxide, phosphorus silicate glass, boron phosphorus silicate glass, silicon oxyfluoride, fluorinated amorphous carbon, and the like can be given.

[0133] The present embodiment can also be applied to materials other than insulating materials such as silicon oxide. As such materials, 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; phase-change materials such as GeSbTe; inorganic conductive materials such as ITO; polymer resin materials such as polyimide-based, polybenzoxazole-based, acrylic-based, epoxy-based, and phenol-based materials; and the like can be given.

[0134] The present embodiment can be applied not only to polishing targets in a film shape but also to various substrates composed of glass, silicon, SiC, SiGe, Ge, GaN, GaP, GaAs, sapphire, plastic, and the like.

[0135] The present embodiment can be used not only in the manufacture of semiconductor elements but also in the manufacture of image display devices such as TFTs and organic ELs; optical components 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; magnetic storage devices such as magnetic disks and magnetic heads; and the like.

[0136] The manufacturing method of the component according to the present embodiment includes a singulation process of singulating a substrate that has been polished by the polishing method according to the present embodiment. The singulation process can be, for example, a process of cutting a wafer (e.g., a semiconductor wafer) that has been polished by the polishing method according to the present embodiment to obtain a chip (e.g., a semiconductor chip). The manufacturing method of the component according to the present embodiment can include a process of polishing a substrate by the polishing method according to the present embodiment before the singulation process. The component according to the present embodiment is, for example, a chip (e.g., a semiconductor chip). The component according to the present embodiment is a component obtained by the manufacturing method of the component according to the present embodiment. The electronic device according to the present embodiment includes the component according to the present embodiment.

[0137] Example

[0138] Hereinafter, the present application will be specifically described according to examples. However, the present application is not limited to the following examples.

[0139] Preparation of slurry containing abrasive grains

[0140] (Slurry A)

[0141] Preparation of cerium oxide slurry

[0142] A cerium oxide slurry (pH: 7) containing 5.0 mass% (solid content) of cerium oxide particles (1st particles) was prepared by mixing cerium oxide particles and ammonium dihydrogen phosphate (molecular weight: 97.99) manufactured by Wako Pure Chemical Corporation under the trade name: "Ammonium Dihydrogen Phosphate". The amount of ammonium dihydrogen phosphate was adjusted to 1 mass% based on the total amount of cerium oxide particles.

[0143] An appropriate amount of the cerium oxide slurry was introduced into Microtrac MT3300EXII manufactured by Microtrac BEL Corp. under the trade name: "Microtrac MT3300EXII", and the average particle diameter of the cerium oxide particles was measured. The average particle diameter value shown was obtained as the average particle diameter (average secondary particle diameter). The average particle diameter of the cerium oxide particles in the cerium oxide slurry was 145 nm.

[0144] An appropriate amount of the cerium oxide slurry was introduced into Delsa Nano C manufactured by Beckman Coulter, Inc. under the trade name: "Delsa Nano C", and measurement was performed twice at 25°C. The average value of the zeta potential shown was obtained as the zeta potential. The zeta potential of the cerium oxide particles in the cerium oxide slurry was -55 mV.

[0145] [Preparation of Cerium Hydroxide Slurry]

[0146] {Synthesis of Cerium Hydroxide}

[0147] A solution was obtained by mixing 480 g of a 50 mass% aqueous solution of Ce(NH4)2(NO3)6 (manufactured by NIHON KAGAKU SANGYO CO., LTD. under the trade name: "CAN50 Liquid") with 7450 g of pure water. Next, a precipitate containing cerium hydroxide was obtained by adding 750 g of an aqueous imidazole solution (10 mass% aqueous solution, 1.47 mol / L) dropwise at a mixing rate of 5 mL / min while stirring the solution. The synthesis of cerium hydroxide was performed at a temperature of 20°C and a stirring rate of 500 min -1 A 3-blade pitched paddle with a blade length of 5 cm was used for stirring.

[0148] After centrifugation (4000 min -1 , 5 minutes) of the precipitate (precipitate containing cerium hydroxide), the liquid phase was removed by decantation, thereby performing solid-liquid separation. After mixing 10 g of the particles obtained by solid-liquid separation and 990 g of water, the particles were dispersed in water using an ultrasonic cleaner, thereby preparing a cerium hydroxide slurry containing cerium hydroxide particles (2nd particles) (particle content: 1.0 mass%).

[0149] {Measurement of Average Particle Diameter}

[0150] The average particle diameter (average secondary particle diameter) of the cerium hydroxide particles in the cerium hydroxide slurry was measured using Beckman Coulter, Inc. manufactured, trade name: N5, and the following procedure, and the result was 10 nm. First, after about 1 mL of a measurement sample (cerium hydroxide slurry. Water dispersion) containing 1.0 mass% of cerium hydroxide particles was put into a 1 cm square cell, and the cell was set in N5. As the measurement sample information of the software of N5, the refractive index was set to 1.333, and the viscosity was set to 0.887 mPa-s, and measurement was performed at 25°C, and the value shown as Unimodal Size Mean was read.

[0151] {Measurement of ζ potential}

[0152] After an appropriate amount of cerium hydroxide slurry was put into Beckman Coulter, Inc. manufactured, trade name: Delsa Nano C, and measurement was performed twice at 25°C. The average value of the ζ potential shown was obtained as the ζ potential. The ζ potential of the cerium hydroxide particles in the cerium hydroxide slurry was +50 mV.

[0153] {Structural analysis of cerium hydroxide particles}

[0154] After an appropriate amount of cerium hydroxide slurry was taken, cerium hydroxide particles were isolated by vacuum drying, and a sample was obtained by sufficiently washing with pure water. Regarding the obtained sample, the result of measurement based on FT-IR ATR method, in addition to the peak based on hydroxide ions (OH - ) of the cerium hydroxide particles, a peak based on nitrate ions (NO3 - ) was also observed. And, regarding the same sample, the result of XPS (N-XPS) measurement for nitrogen was performed, and a peak based on NH4 + was not observed, and a peak based on nitrate ions was observed. From these results, it was confirmed that the cerium hydroxide particles contained at least a part of particles having nitrate ions bonded to cerium elements. And, since the cerium hydroxide particles contained at least a part of particles having hydroxide ions bonded to cerium elements, it was confirmed that the cerium hydroxide particles contained cerium hydroxide. From these results, it was confirmed that the hydroxide of cerium contained hydroxide ions bonded to cerium elements.

[0155] [Preparation of slurry A]

[0156] A slurry A containing composite particles including cerium oxide particles and cerium hydroxide particles in contact with the cerium oxide particles was prepared by mixing the cerium hydroxide slurry 20 g and deionized water 1940 g while stirring at 300 rpm using two stirring blades. Next, after mixing the cerium oxide slurry 40 g while stirring the mixture, a slurry A containing composite particles including cerium oxide particles and cerium hydroxide particles in contact with the cerium oxide particles was prepared by stirring while irradiating ultrasonic waves using an ultrasonic cleaner (device name: US-105) manufactured by SND Company Limited.

[0157] (Slurry B)

[0158] A slurry B containing 5.0 mass% (solid content) of cerium oxide particles (pH: 4) was prepared by mixing cerium oxide particles and acetic acid (molecular weight: 60.05). The amount of acetic acid was adjusted to 1 mass% based on the total amount of cerium oxide particles.

[0159] The average particle diameter of the cerium oxide particles was measured by placing an appropriate amount of the slurry B in a product name: Microtrac MT3300EXII manufactured by Microtrac BEL Corp. The average particle diameter value shown was obtained as the average particle diameter (average secondary particle diameter). The average particle diameter of the cerium oxide particles in the slurry B was 140 nm.

[0160] Preparation of CMP polishing liquid

[0161] (Example 1)

[0162] A CMP polishing liquid containing abrasive particles 0.10 mass%, a hydroxy acid component 0.40 mass%, a polyoxyethylene stearylamine 0.05 mass%, and alanine 0.09 mass% based on the total mass of the CMP polishing liquid (pH: 4.0) was obtained by mixing the above slurry A, 2,2-bis(hydroxymethyl)butyric acid (hydroxy acid component), polyoxyethylene stearylamine (manufactured by NOF CORPORATION, product name: NYMEEN S-220, number of carbon atoms a of hydrocarbon group: 18, total number of oxyalkylene groups: 20, HLB value: 15.4), alanine (pH adjuster, pi = 6.00), deionized water. In the CMP polishing liquid, as the abrasive particles, composite particles including cerium oxide particles and cerium hydroxide particles in contact with the cerium oxide particles were contained, and the mass ratio of the cerium oxide particles to the cerium hydroxide particles was 10:1 (cerium oxide:cerium hydroxide). In the CMP polishing liquid, as the abrasive particles, in addition to the above composite particles, cerium hydroxide particles not in contact with the cerium oxide particles (free particles) were also contained.

[0163] (Example 2)

[0164] polyoxyethylene polycyclic phenyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: N-714, number of carbon atoms a of hydrocarbon group: 30, total number of oxyalkylene groups: 14, HLB value: 15.0) was used instead of polyoxyethylene stearylamine, and a CMP polishing liquid (pH: 4.0) containing the composite particles and free particles was prepared in the same manner as in Example 1, except for this.

[0165] (Example 3)

[0166] polyoxyethylene polycyclic phenyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: N-723, number of carbon atoms a of hydrocarbon group: 30, total number of oxyalkylene groups: 23, HLB value: 16.6) was used instead of polyoxyethylene stearylamine, and a CMP polishing liquid (pH: 4.0) containing the composite particles and free particles was prepared in the same manner as in Example 1, except for this.

[0167] (Example 4)

[0168] polyoxyethylene polycyclic phenyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: N-780, number of carbon atoms a of hydrocarbon group: 30, total number of oxyalkylene groups: 80, HLB value: 18.9) was used instead of polyoxyethylene stearylamine, and a CMP polishing liquid (pH: 4.0) containing the composite particles and free particles was prepared in the same manner as in Example 1, except for this.

[0169] (Example 5)

[0170] polyoxyethylene polycyclic phenyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: N-780) was used instead of polyoxyethylene stearylamine, and a CMP polishing liquid (pH: 4.0) containing the composite particles and free particles was prepared in the same manner as in Example 1, except for this.

[0171] (Example 6)

[0172] polyoxyethylene polycyclic phenyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: N-780) was used instead of polyoxyethylene stearylamine, and a CMP polishing liquid (pH: 4.0) containing the composite particles and free particles was prepared in the same manner as in Example 1, except for this.

[0173] (Example 7)

[0174] Slurry A was changed to Slurry B, and polyoxyethylene stearylamine was changed to polyoxyethylene polycyclic phenyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: N-780), and otherwise, in the same manner as in Example 1, a polishing slurry for CMP (content of abrasive grains (cerium oxide particles): 0.10 mass%, pH: 4.0) was prepared.

[0175] (Comparative Example 1)

[0176] Polyoxyethylene stearylamine was changed to polyoxyethylene monophenyl ether (manufactured by TAKEMOTO OIL & FAT CO., LTD., trade name: PIONIN 6140, number of carbon atoms a of hydrocarbon group: 6, total number of oxyalkylene groups: 10, HLB value: 16.4), and otherwise, in the same manner as in Example 1, a polishing slurry for CMP (pH: 4.0) was prepared.

[0177] (Comparative Example 2)

[0178] Polyoxyethylene stearylamine was changed to polyoxyethylene cumylphenyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: CMP-11, number of carbon atoms a of hydrocarbon group: 15, total number of oxyalkylene groups: 11, HLB value: 13.6), and otherwise, in the same manner as in Example 1, a polishing slurry for CMP (pH: 4.0) was prepared.

[0179] (Comparative Example 3)

[0180] Polyoxyethylene stearylamine was changed to polyoxyethylene laurylamine (manufactured by NOF CORPORATION, trade name: NYMEEN L-207, number of carbon atoms a of hydrocarbon group: 12, total number of oxyalkylene groups: 7, HLB value: 12.5), and otherwise, in the same manner as in Example 1, a polishing slurry for CMP (pH: 4.0) was prepared.

[0181] (Comparative Example 4)

[0182] Polyoxyethylene stearylamine was changed to polyoxyethylene alkyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: N-2308, number of carbon atoms a of hydrocarbon group: 12, total number of oxyalkylene groups: 8, HLB value: 13.2), and otherwise, in the same manner as in Example 1, a polishing slurry for CMP (pH: 4.0) was prepared.

[0183] (Comparative Example 5)

[0184] Polyoxyethylene stearylamine was changed to polyoxyethylene trimethylolpropane ether (manufactured by Nippon Nyukazai Co., Ltd., trade name: TMP-60, number of carbon atoms a of hydrocarbon group: 0, total number of oxyalkylene groups: 24, HLB value: 15.2), and otherwise, a polishing solution for CMP (pH: 4.0) was prepared in the same manner as in Example 1.

[0185] (Comparative Example 6)

[0186] The amount of 2,2-bis(hydroxymethyl)butyric acid was not added, and the amount of deionized water was increased, and otherwise, a polishing solution for CMP (pH: 4.0) was prepared in the same manner as in Example 1.

[0187] Measurement of ζ potential

[0188] After an appropriate amount of the polishing solution for CMP was put into a product name: Delsa Nano C manufactured by Beckman Coulter, Inc., and measurement was performed twice at 25°C. The average of the ζ potentials shown was obtained as the ζ potential. In all of the examples and comparative examples, the ζ potential of the abrasive grains in the polishing solution for CMP was positive.

[0189] Evaluation of CMP

[0190] The polishing of the polished substrate was performed under the following polishing conditions using the above-mentioned polishing solution for CMP.

[0191] Polishing device: MIRRA-3400 (manufactured by Applied Materials Inc.)

[0192] Flow rate of the polishing solution for CMP: 200 mL / min

[0193] Polished substrate: The following patternless wafer and pattern wafer

[0194] Polishing pad: Foamed polyurethane resin having closed-cell foam (manufactured by ROHM AND HAAS ELECTRONIC MATERIALS CMP INC., model IC1010)

[0195] Polishing pressure: 3.0 psi

[0196] Rotational speed of the polished substrate and the polishing stage: Polished substrate / polishing stage = 90 / 87 rpm

[0197] Polishing time:

[0198] Patternless wafer: 1 min

[0199] Using the above-described polishing slurry, a wafer, which was polished to expose a silicon nitride film (of a pattern wafer) described later, was additionally polished (over-polished) by an amount of 20 nm and 40 nm. At this time, the amount of the remaining step (recess) and the polishing amount of the silicon nitride film were confirmed.

[0200] Cleaning of the wafer: After cleaning with water while applying ultrasonic waves after the CMP treatment, drying was performed using a spin dryer.

[0201] [Non-patterned wafer]

[0202] As the non-patterned wafer, a polished substrate having a silicon oxide film with a thickness of 2 μm formed by a plasma CVD method on a silicon substrate was used.

[0203] [Patterned wafer]

[0204] As the patterned wafer on which a simulated pattern was formed, a SEMATECH-manufactured, 864 wafer (trade name, diameter: 200 mm) was used. This patterned wafer was obtained by laminating a silicon nitride film as a stopper layer (stopper layer film) on a silicon substrate, and then laminating a silicon oxide film (SiO2 film) as an insulating film on the silicon substrate and the silicon nitride film in a manner to fill the stopper layer and a trench formed in an exposure process. The silicon oxide film was formed by an HDP (High Density Plasma) method.

[0205] As the patterned wafer, a wafer having a line (projection) & space (recess) with a pitch of 50 μm and a projection pattern density of 50% in a portion was used. The line & space is a pattern in which an Active portion masked by a stopper layer film as a projection and a Trench portion in which a groove as a recess is formed are alternately arranged. For example, "the pitch of the line & space is 50 μm" means that the total of the widths of the line portion and the space portion is 50 μm. Also, for example, "the pitch of the line & space is 50 μm, and the projection pattern density is 50%" means a pattern in which a projection width: 25 μm and a recess width: 25 μm are alternately arranged.

[0206] For evaluation of the polishing of the pattern wafer, a wafer in which the residual step difference was about 30 nm was used, which was polished by using a polishing liquid having a self-stopping property (a property in which the polishing rate decreases as the residual step difference of the simulated pattern decreases). Specifically, a wafer in which the convex portion of the silicon nitride film in the 50 μm pitch, 50% density pattern was exposed was polished using a polishing liquid in which HS-8005-D4 (trade name) manufactured by Hitachi Chemical Company, Ltd., HS-7303GP (trade name) manufactured by Hitachi Chemical Company, Ltd., and water were mixed at a ratio of 1 : 1.2 : 7.8.

[0207] [No-pattern wafer evaluation (polishing rate)]

[0208] The polishing rate of the polished film (silicon oxide film) was calculated from the following equation with respect to the polished substrate on which polishing and cleaning were performed under the above conditions. In addition, the film thickness difference of the polished film before and after polishing was calculated using an optical interference film thickness measuring device (manufactured by Filmetrics, INC., trade name: F80). The measurement results are shown in Tables 1 and 2.

[0209] Polishing rate (RR) = (film thickness difference of the polished film before and after polishing [nm]) / (polishing time [min])

[0210] [Pattern wafer evaluation]

[0211] The residual film thickness of the silicon nitride film of the convex portion (convex portion in the 50 μm pitch, 50% density pattern) and the residual film thickness of the silicon oxide film of the concave portion of the pattern wafer on which polishing and cleaning were performed under the above conditions were measured, and the residual step difference was calculated from the following equation. In the equation, "350 nm + residual film thickness of silicon nitride film [nm]" indicates the film thickness of the convex portion. The case where the residual step difference was 12 nm or less was judged to be good. In addition, the polishing amount of the silicon nitride film was calculated from the following equation using the difference between the initial film thickness and the film thickness after polishing (residual film thickness) of the silicon nitride film. The film thickness of each of the polished films before and after polishing was calculated using an optical interference film thickness measuring device (manufactured by Nanometrics Inc., trade name: Nanospec AFT-5100). The measurement results are shown in Tables 1 and 2.

[0212] Residual step difference = (350 nm + residual film thickness of silicon nitride film [nm]) - (residual film thickness of silicon oxide film of concave portion [nm])

[0213] Polishing amount of silicon nitride film = 1500 nm - residual film thickness of silicon nitride film of convex portion [nm]

[0214] [Table 1]

[0215]

[0216] [Table 2]

[0217]

Claims

1. A polishing liquid comprising abrasive grains, at least one hydroxy acid component selected from the group consisting of hydroxy acids and salts thereof, and a compound Z, the abrasive grains contain cerium oxide, the content of the cerium oxide exceeds 50 mass% based on the entire abrasive grains, the compound Z has a hydrocarbon group which can be substituted and a polyoxyalkylene group, Z value represented by the following general formula (1) is 20 or more, Z = 0.1 x a 2 x b / c... (1) in formula (1), a represents the number of carbon atoms of the hydrocarbon group, b represents the total number of oxyalkylene groups in the compound Z, and c represents the HLB value of the compound Z.

2. The polishing liquid according to claim 1, wherein the average particle diameter of the abrasive grains is 16 to 1050 nm.

3. The polishing liquid according to claim 1, wherein the zeta potential of the abrasive grains is positive.

4. The polishing liquid according to claim 1, wherein the zeta potential of the abrasive grains is 10 to 200 mV.

5. The polishing liquid according to claim 1, wherein the abrasive grains further contain cerium hydroxide.

6. The polishing liquid according to claim 1, wherein the abrasive grains contain first particles and second particles in contact with the first particles, the particle diameter of the second particles is smaller than that of the first particles, the first particles contain the cerium oxide, the second particles contain a cerium compound.

7. The polishing liquid according to claim 6, wherein the particle diameter of the first particles is 15 to 1000 nm.

8. The polishing liquid according to claim 6, wherein the particle diameter of the second particles is 1 to 50 nm.

9. The polishing liquid according to claim 1, wherein the content of the abrasive grains is 0.005 to 20 mass% based on the total mass of the polishing liquid.

10. The polishing liquid according to claim 1, wherein the content of the abrasive grains is 0.01 to 1 mass% based on the total mass of the polishing liquid.

11. The polishing liquid according to claim 1, wherein the total number of carboxyl groups and carboxylate groups in the hydroxy acid component is 1.

12. The polishing liquid according to claim 1, wherein the number of hydroxyl groups in the hydroxy acid component is 1 to 2.

13. The polishing liquid according to claim 1, wherein the number of hydroxyl groups in the hydroxy acid component is 2 or more.

14. The polishing liquid according to claim 1, wherein the number of hydroxyl groups in the hydroxy acid component is 2.

15. The polishing liquid according to claim 1, wherein the number of hydroxyl groups in the hydroxy acid component is 3.

16. The polishing liquid according to claim 1, wherein the hydroxy acid component contains at least one selected from the group consisting of glycolic acid, glyceric acid, lactic acid, 2,2-bis(hydroxymethyl)propionic acid, 2,2-bis(hydroxymethyl)butyric acid, N,N-bis(2-hydroxyethyl)glycine, N-[2-hydroxy-l,l-bis(hydroxymethyl)ethyl]glycine, N,N-dihydroxyethylglycine, tris(hydroxymethyl)methylglycine, tyrosine, serine, and salts of these.

17. The polishing liquid according to claim 1, wherein the hydroxy acid component contains lactic acid.

18. The polishing liquid according to claim 1, wherein The hydroxy acid component contains 2,2-bis(hydroxymethyl)butyric acid.

19. The polishing liquid according to claim 1, wherein The hydroxy acid component contains 2,2-bis(hydroxymethyl)butyric acid.

20. The polishing liquid according to claim 1, wherein The hydroxy acid component contains tris(hydroxymethyl)methylglycine.

21. The polishing liquid according to claim 1, wherein The content of the hydroxy acid component is 0.01 to 5.0 mass% based on the total mass of the polishing liquid.

22. The polishing liquid according to claim 1, wherein The content of the hydroxy acid component is 0.01 to 1.0 mass% based on the total mass of the polishing liquid.

23. The polishing liquid according to claim 1, wherein The content of the hydroxy acid component is 10 to 1000 mass parts relative to 100 mass parts of the abrasive grains.

24. The polishing liquid according to claim 1, wherein The content of the hydroxy acid component is 100 to 500 mass parts relative to 100 mass parts of the abrasive grains.

25. The polishing liquid according to any one of claims 1 to 24, wherein The number of carbon atoms of the hydrocarbon group of the compound Z is 1 to 50.

26. The polishing liquid according to any one of claims 1 to 24, wherein The number of carbon atoms of the hydrocarbon group of the compound Z is 12 to 30.

27. The polishing liquid according to any one of claims 1 to 24, wherein The number of carbon atoms of the hydrocarbon group of the compound Z is 18 or more.

28. The polishing liquid according to any one of claims 1 to 24, wherein The total number of oxyalkylene groups in the compound Z is 2 to 100.

29. The polishing liquid according to any one of claims 1 to 24, wherein The total number of oxyalkylene groups in the compound Z is 14 to 80.

30. The polishing liquid according to any one of claims 1 to 24, wherein The HLB value of the compound Z is 8.0 or more.

31. The polishing liquid according to any one of claims 1 to 24, wherein The HLB value of the compound Z is 14.0 or more.

32. The polishing liquid according to any one of claims 1 to 24, wherein The Z value of the compound Z is 30 to 1000.

33. The polishing liquid according to any one of claims 1 to 24, wherein The Z value of the compound Z is 50 to 1000.

34. The polishing liquid according to any one of claims 1 to 24, wherein The Z value of the compound Z is 100 to 1000.

35. The polishing liquid according to any one of claims 1 to 24, wherein The Z value of the compound Z is 150 to 1000.

36. The polishing liquid according to any one of claims 1 to 24, wherein The compound Z contains a compound represented by the following general formula (z1), In formula (z1), A 1 represents an alkylene group, R 1 represents the hydrocarbon group, and n1 represents an integer of 2 or more.

37. The polishing liquid according to claim 36, wherein The hydrocarbon group of the compound represented by the general formula (z1) is an aryl group having a plurality of aromatic rings.

38. The polishing liquid according to any one of claims 1 to 24, wherein The compound Z includes a compound having a nitrogen atom to which the hydrocarbon group and the polyoxyalkylene are bonded.

39. The polishing liquid according to any one of claims 1 to 24, wherein, The compound Z includes a compound represented by the following general formula (z2), In formula (z2), A 21 and A 22 each independently represents an alkylene group, R 2 represents the hydrocarbon group, and n21 and n22 each independently represent an integer of 2 or more.

40. The polishing liquid according to claim 39, wherein, The hydrocarbon group of the compound represented by the general formula (z2) is an alkyl group.

41. The polishing liquid according to any one of claims 1 to 24, wherein, The compound Z includes at least one selected from the group consisting of a polyoxyethylene alkylamine, a polyoxyethylene distyrylphenyl ether, and a polyoxyethylene polycyclic phenyl ether.

42. The polishing liquid according to any one of claims 1 to 24, wherein, The content of the compound Z is 0.01 to 5.0 mass% based on the total mass of the polishing liquid.

43. The polishing liquid according to any one of claims 1 to 24, wherein, The content of the compound Z is 0.01 to 0.5 mass% based on the total mass of the polishing liquid.

44. The polishing liquid according to any one of claims 1 to 24, wherein, The content of the compound Z is 1 to 100 mass parts with respect to 100 mass parts of the abrasive grains.

45. The polishing liquid according to any one of claims 1 to 24, wherein, The content of the compound Z is 10 to 50 mass parts with respect to 100 mass parts of the abrasive grains.

46. The polishing liquid according to any one of claims 1 to 24, wherein, The content of the compound Z is 1 to 100 mass parts with respect to 100 mass parts of the hydroxy acid component.

47. The polishing liquid according to any one of claims 1 to 24, wherein, The content of the compound Z is 5 to 50 mass parts with respect to 100 mass parts of the hydroxy acid component.

48. The polishing liquid according to any one of claims 1 to 24, wherein, The pH is 2.0 to 6.

0.

49. The polishing liquid according to any one of claims 1 to 24, wherein, The pH is 2.5 to 4.

5.

50. A polishing liquid set, wherein The constituent components of the polishing liquid according to any one of claims 1 to 49 are stored as a first liquid containing the abrasive grains and a second liquid containing the hydroxy acid component and the compound Z.

51. A polishing method comprising a polishing step of polishing a surface to be polished using the polishing liquid according to any one of claims 1 to 49 or a polishing liquid obtained by mixing the first liquid and the second liquid in the polishing liquid set according to claim 50.

52. The polishing method according to claim 51, wherein The surface to be polished includes silicon oxide.

53. The polishing method according to claim 52, wherein The surface to be polished further includes silicon nitride.

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