JP2007073548A - Polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing method by which wiring of a semiconductor device can be formed appropriately. <P>SOLUTION: The polishing method includes a first preliminary polishing step, a second preliminary polishing step, and a finishing polishing step. In the second preliminary polishing step, a second polishing composition is used which contains such a compound as a protective film forming agent that is represented by a general formula, ROR'COOH or ROR'OPO<SB>3</SB>H<SB>2</SB>(R: alkyl group or alkyl phenyl group; R': polyoxyethylene group, polyoxypropylene group or poly(oxyethylene, oxypropylene) group). In the finishing polishing step, a third polishing composition is used which contains less than 3 g/L of triazole having a hydrophobic functional group as well as a six-membered frame. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polishing method using a polishing composition.

  In forming a wiring of a semiconductor device, first, a barrier layer and a conductor layer are sequentially formed on an insulator layer having a trench. Thereafter, at least a portion of the conductor layer (outside portion of the conductor layer) located outside the trench and a portion of the barrier layer (outside portion of the barrier layer) located outside the trench are removed by chemical mechanical polishing. The polishing for removing at least the outer portion of the conductor layer and the outer portion of the barrier layer is usually performed in a first polishing step and a second polishing step. In the first polishing step, a part of the outer portion of the conductor layer is removed to expose the upper surface of the outer portion of the barrier layer. In the subsequent second polishing step, at least the remaining portion of the outer portion of the conductor layer and the outer portion of the barrier layer are removed to expose the insulator layer and obtain a flat surface.

Patent Documents 1 and 2 disclose polishing compositions that can be used in the first polishing step and the second polishing step. The polishing compositions of Patent Documents 1 and 2 contain a protective film forming agent such as benzotriazole, an oxidizing agent such as hydrogen peroxide, and an etching agent such as glycine. However, when these polishing compositions are used, there is a required performance related to a phenomenon called dishing, in which the removal of the portion of the conductor layer located in the trench proceeds excessively and the level of the upper surface of the conductor layer is lowered. There was a problem that it was not fully satisfied, or organic residue derived from benzotriazole was likely to remain on the surface of the polished object as a foreign substance.
JP-A-8-83780 International Publication No. 00/39844 Pamphlet

  An object of the present invention is to provide a polishing method capable of better forming the wiring of a semiconductor device.

In order to achieve the above object, the invention described in claim 1 provides the following polishing method for an object to be polished. The polishing object includes an insulator layer having a trench, a barrier layer provided on the insulator layer, and a conductor layer provided on the barrier layer, and each of the barrier layer and the conductor layer includes: An inner portion located in the trench and an outer portion located outside the trench. The polishing method includes a preliminary polishing step of polishing an object to be polished so as to remove a part of the outer portion of the conductor layer and expose the upper surface of the outer portion of the barrier layer, and at least the remaining portion of the outer portion of the conductor layer and the barrier And a final polishing step of polishing a polishing object from which a part of the outer portion of the conductor layer has been removed in order to remove the outer portion of the layer. The pre-polishing step includes a first pre-polishing step for polishing an object to be polished to remove most of the conductor layer portion to be removed in the pre-polishing step, and a remaining portion of the conductor layer portion to be removed. A second pre-polishing step for polishing the object to be removed from which most of the portion of the conductor layer to be removed is removed. The polishing of the object to be polished in the second preliminary polishing step is performed using a preliminary polishing composition containing a protective film forming agent, an oxidizing agent, and an etching agent. The protective film forming agent includes at least one compound selected from benzotriazole and a benzotriazole derivative, a general formula ROR′COOH and a general formula ROR′OPO ₃ H ₂ (R represents an alkyl group or an alkylphenyl group, and R ′ Represents at least one compound selected from compounds represented by a polyoxyethylene group, a polyoxypropylene group or a poly (oxyethylene / oxypropylene) group), and the pH of the preliminary polishing composition is 8 or more. is there.

The invention according to claim 2 is characterized in that at least one compound selected from the compounds represented by the general formula ROR′COOH and the general formula ROR′OPO ₃ H ₂ contained in the preliminary polishing composition is a polyoxyethylene alkyl ether. The method according to claim 1, which is acetic acid or polyoxyethylene alkylphenyl ether phosphoric acid.

  In the invention according to claim 3, the preliminary polishing composition has the general formula ROR ′ (R represents an alkyl group or an alkylphenyl group, and R ′ represents a polyoxyethylene group or a polyoxypropylene group). A method according to claim 1 or 2 further comprising a compound represented.

  According to a fourth aspect of the present invention, the polishing of the object to be polished in the final polishing step is for final polishing containing a triazole having a six-membered ring skeleton, a water-soluble polymer, an oxidizing agent, and abrasive grains. The method according to any one of claims 1 to 3, wherein the method is performed using a composition. The triazole has a hydrophobic functional group in a six-membered ring skeleton, the content of the triazole in the finish polishing composition is 3 g / L or less, and the pH of the finish polishing composition is 7 or more. .

  The invention according to claim 5 provides the following polishing method. That is, in the polishing method according to claim 6, the polishing of the object to be polished in the final polishing step is a finish containing a triazole having a six-membered ring skeleton, a water-soluble polymer, an oxidizing agent, and abrasive grains. It is performed using a polishing composition. The triazole has a hydrophobic functional group in a six-membered ring skeleton, the content of the triazole in the finish polishing composition is 3 g / L or less, and the pH of the finish polishing composition is 7 or more. .

  The invention according to claim 6 provides the method according to claim 4 or 5, wherein the finish polishing composition further comprises at least one of carboxybenzotriazole and aminobenzotriazole.

  ADVANTAGE OF THE INVENTION According to this invention, the grinding | polishing method which can form the wiring of a semiconductor device better is provided.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
In the present embodiment, the wiring of the semiconductor device is formed as follows. First, as shown in FIG. 1A, a barrier layer 13 and a conductor layer 14 are sequentially formed on an insulator layer 12 provided in a semiconductor substrate (not shown) and having a trench 11. Thereafter, at least a portion of the conductor layer 14 located outside the trench 11 (outside portion of the conductor layer 14) and a portion of the barrier layer 13 located outside the trench 11 (outside portion of the barrier layer 13) are removed by chemical mechanical polishing. To do. As a result, as shown in FIG. 1D, at least a part of the portion of the barrier layer 13 (inner portion of the barrier layer 13) located in the trench 11 and a portion of the conductor layer 14 located in the trench 11 At least a part of (the inner portion of the conductor layer 14) remains on the insulator layer 12. Thus, the portion of the conductor layer 14 remaining on the insulator layer 12 functions as the wiring of the semiconductor device.

The insulator layer 12 is made of, for example, silicon dioxide, fluorine-doped silicon dioxide (SiOF), or carbon-doped silicon dioxide (SiOC).
Prior to the formation of the conductor layer 14, the barrier layer 13 is formed on the insulator layer 12 so as to cover the surface of the insulator layer 12. The barrier layer 13 is made of, for example, tantalum, a tantalum alloy, or tantalum nitride. The thickness of the barrier layer 13 is smaller than the depth of the trench 11.

  Following the formation of the barrier layer 13, the conductor layer 14 is formed on the barrier layer 13 so that at least the trench 11 is filled. The conductor layer 14 is formed from, for example, copper or a copper alloy.

  When removing at least the outer portion of the conductor layer 14 and the outer portion of the barrier layer 13 by chemical mechanical polishing, first, most of the outer portion of the conductor layer 14 is removed as shown in FIG. Pre-polishing step). This step is terminated before the upper surface of the outer portion of the barrier layer 13 is exposed. Thereafter, as shown in FIG. 1C, a part of the remaining portion of the outer portion of the conductor layer 14 is removed so as to expose the upper surface of the outer portion of the barrier layer 13 (second preliminary polishing step). Finally, as shown in FIG. 1D, at least the remaining portion of the outer portion of the conductor layer 14 and the outer portion of the barrier layer 13 are removed (finishing) so as to expose the insulator layer 12 and obtain a flat surface. Polishing process).

  In the polishing for removing most of the outer portion of the first conductor layer 14, the first polishing composition (first preliminary polishing composition) is used. A second polishing composition (second pre-polishing composition) is used in polishing for removing a part of the remaining portion of the outer portion of the conductor layer 14 that follows. In the final polishing for removing at least the remainder of the outer portion of the conductor layer 14 and the outer portion of the barrier layer 13, a third polishing composition (final polishing composition) is used. Hereinafter, the first to third polishing compositions will be described in order.

<< First polishing composition >>
The first polishing composition is produced by mixing a predetermined amount of a water-soluble polymer, abrasive grains, and water. Accordingly, the first polishing composition consists essentially of a water-soluble polymer, abrasive grains, and water.

  The water-soluble polymer in the first polishing composition is a first polishing composition that polishes the conductor layer 14 due to the second or third polishing composition mixed in the first polishing composition. It is blended in order to suppress a decrease in the ability. The water-soluble polymer contained in the first polishing composition is at least one compound selected from polysaccharides and polyvinyl alcohol, but the ability of the first polishing composition to decrease due to the incorporation of another polishing composition. In order to strongly suppress the above, pullulan is preferable. The polysaccharide may be a storage polysaccharide such as starch, amylopectin and glycogen, a structural polysaccharide such as cellulose, pectin and hemicellulose, or an extracellular polysaccharide such as pullulan and erucinan.

  When the content of the water-soluble polymer in the first polishing composition is less than 0.01% by mass, more specifically, when it is less than 0.05% by mass, it is due to the mixing of another polishing composition. A decrease in the ability of the first polishing composition is not significantly suppressed. Therefore, in order to strongly suppress a decrease in the performance of the first polishing composition due to the mixing of another polishing composition, the content of the water-soluble polymer in the first polishing composition is 0.01% by mass. It is preferable that it is above, and more preferably 0.05% by mass or more. On the other hand, when the content of the water-soluble polymer in the first polishing composition is more than 10% by mass, more specifically, when it is more than 5% by mass, the first polishing composition for polishing the conductor layer 14 is used. There is a risk that the ability of the object will be reduced. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the content of the water-soluble polymer in the first polishing composition is preferably 10% by mass or less, more preferably 5% by mass. It is as follows.

  The abrasive grains in the first polishing composition play a role of mechanically polishing the object to be polished, and contribute to improving the ability of the first polishing composition to polish the conductor layer 14. In order to obtain a higher polishing rate with respect to the conductor layer 14, the abrasive grains contained in the first polishing composition are silica such as calcined silica, fumed silica, colloidal silica, or alumina such as colloidal alumina. It is preferable that Among these, fumed silica, fumed alumina, or colloidal silica is more preferable in that the surface defects of the polished object after polishing can be reduced.

  When the content of abrasive grains in the first polishing composition is less than 0.1% by mass, more specifically, when the content is less than 0.5% by mass, the first polishing composition for polishing the conductor layer 14 is used. The ability of things is not improved so much. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the content of abrasive grains in the first polishing composition is preferably 0.1% by mass or more, more preferably 0.5%. It is at least mass%. On the other hand, when the content of the abrasive grains in the first polishing composition is more than 10% by mass, more specifically, when the content is more than 5% by mass, the abrasive grains may easily aggregate. Therefore, in order to suppress agglomeration of abrasive grains, the content of abrasive grains in the first polishing composition is preferably 10% by mass or less, more preferably 5% by mass or less.

  When the average primary particle diameter of the abrasive grains contained in the first polishing composition is smaller than 10 nm, more specifically, smaller than 20 nm, the ability of the first polishing composition to polish the conductor layer 14 is not so great. Not improved. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the average primary particle diameter of the abrasive grains contained in the first polishing composition is preferably 10 nm or more, more preferably 20 nm or more. . On the other hand, when the average primary particle diameter of the abrasive grains contained in the first polishing composition is larger than 200 nm, more specifically, larger than 120 nm, the abrasive grains may easily aggregate. Therefore, in order to suppress agglomeration of abrasive grains, the average primary particle diameter of the abrasive grains contained in the first polishing composition is preferably 200 nm or less, and more preferably 120 nm or less. In addition, the average primary particle diameter of an abrasive grain is computed from the specific surface area of the abrasive grain measured by BET method, for example.

<< Second polishing composition >>
The second polishing composition is manufactured to have a pH of 8 or more by mixing a predetermined amount of a protective film forming agent, an oxidizing agent, an etching agent (complex forming agent), abrasive grains, and water. Accordingly, the second polishing composition substantially comprises a protective film forming agent, an oxidizing agent, an etching agent, abrasive grains, and water.

  The protective film forming agent in the second polishing composition has a function of forming a protective film on the surface of the object to be polished, and forms a protective film on the surface of the conductor layer 14 so that the inner portion of the conductor layer 14 is excessive The occurrence of dishing (see FIG. 2A) is suppressed by suppressing the removal.

  The protective film forming agent contained in the second polishing composition includes at least one compound selected from benzotriazole and benzotriazole derivatives, and compounds represented by the following general formulas (1) and (2) (anions) And at least one compound selected from surfactants). In other words, the second polishing composition is represented by the first protective film forming agent comprising at least one compound selected from benzotriazole and a benzotriazole derivative, and the general formula (1) and the general formula (2). And a second protective film forming agent comprising at least one compound selected from compounds. The benzotriazole derivative is formed, for example, by replacing the hydrogen atom bonded to the five-membered ring of benzotriazole with another atomic group.

ROR'COOH (1)
ROR'OPO ₃ H ₂ (2)
In the formulas (1) and (2), R represents an alkyl group or an alkylphenyl group, and R ′ represents a polyoxyethylene group, a polyoxypropylene group or a poly (oxyethylene / oxypropylene) group.

The first protective film forming agent contained in the second polishing composition is preferably benzotriazole in order to obtain a stronger dishing suppressing action.
When the content of the first protective film forming agent in the second polishing composition is less than 0.001 g / L, more specifically, less than 0.01 g / L, excessive polishing of the conductor layer 14 is performed. There is a risk that a protective film sufficient to suppress the above will not be formed on the surface of the conductor layer 14, and as a result, the occurrence of dishing may not be suppressed so much, or the surface of the conductor layer 14 may be roughened. Therefore, in order to avoid these harmful effects, the content of the first protective film forming agent in the second polishing composition is preferably 0.001 g / L or more, more preferably 0.01 g / L or more. It is. On the other hand, when the content of the first protective film forming agent in the second polishing composition is more than 1 g / L, more specifically, more than 0.1 g / L, the surface of the conductor layer 14 is excessive. Further, since the protective film is formed, the polishing of the conductor layer 14 may be excessively suppressed. Therefore, in order to maintain an appropriate polishing rate for the conductor layer 14, the content of the first protective film forming agent in the second polishing composition is preferably 1 g / L or less, more preferably 0.8. 1 g / L or less.

  In order to obtain a stronger dishing suppressing action, the second protective film forming agent contained in the second polishing composition may be a polyoxyethylene alkyl ether acetic acid such as polyoxyethylene lauryl ether acetic acid, or a polyoxyethylene alkyl phenyl. Ether phosphoric acid is preferred.

  When the content of the second protective film forming agent in the second polishing composition is less than 0.05 g / L, more specifically less than 0.5 g / L, more specifically less than 1 g / L. In this case, the occurrence of dishing is not greatly suppressed. Therefore, in order to strongly suppress the occurrence of dishing, the content of the second protective film forming agent in the second polishing composition is preferably 0.05 g / L or more, more preferably 0.5 g / L. L or more, most preferably 1 g / L or more. On the other hand, when the content of the second protective film forming agent in the second polishing composition is more than 50 g / L, more than 30 g / L, more specifically more than 15 g / L. There is a possibility that the polishing of the conductor layer 14 is excessively suppressed. Therefore, in order to maintain an appropriate polishing rate for the conductor layer 14, the content of the second protective film forming agent in the second polishing composition is preferably 50 g / L or less, more preferably 30 g / L. L or less, most preferably 15 g / L or less.

  When the molecular weight of the second protective film forming agent contained in the second polishing composition is smaller than 200, more specifically, smaller than 400, there is a possibility that a very strong dishing suppressing action cannot be obtained. Therefore, in order to obtain a stronger dishing suppressing action, the molecular weight of the second protective film forming agent contained in the second polishing composition is preferably 200 or more, more preferably 400 or more. On the other hand, the second protective film forming agent is difficult to dissolve in water when the molecular weight is larger than 1000, more specifically, larger than 700. Therefore, in order to improve the solubility of the second protective film forming agent in the second polishing composition, the molecular weight of the second protective film forming agent contained in the second polishing composition is 1000 or less. Is more preferable, and 700 or less is more preferable.

  The second protective film forming agent is used when the number of repeating units in the polyoxyethylene group, polyoxypropylene group or poly (oxyethylene / oxypropylene) group is less than 2, more specifically, less than 3. Becomes difficult to dissolve in water. Therefore, in order to improve the solubility of the second protective film forming agent in the second polishing composition, the polyoxyethylene group, the polyoxyethylene group of the second protective film forming agent contained in the second polishing composition is used. The number of repeating units in the oxypropylene group or poly (oxyethylene / oxypropylene) group is preferably 2 or more, more preferably 3 or more.

  When the HLB (Hydrophilic Lipophilic Balance) value is smaller than 10, more specifically smaller than 11.5, the second protective film forming agent becomes difficult to dissolve in water and becomes a milky state, so that it is polished. It is not suitable for forming a uniform protective film on an object. Therefore, in order to improve the solubility of the second protective film forming agent in the second polishing composition, the HLB value of the second protective film forming agent contained in the second polishing composition is 10 or more. It is preferable that it is 11.5 or more. On the other hand, when the HLB value of the second protective film forming agent contained in the second polishing composition is greater than 16, more specifically, greater than 14, there is a possibility that a very strong dishing suppressing action may not be obtained. . Therefore, in order to obtain a stronger dishing suppressing action, the HLB value of the second protective film forming agent contained in the second polishing composition is preferably 16 or less, more preferably 14 or less. In addition, the HLB value of a 2nd protective film formation agent is calculated | required by the Griffin method, for example.

  The oxidizing agent in the second polishing composition has an action of oxidizing the object to be polished, and contributes to improvement in the ability of the second polishing composition to polish the conductor layer 14 through oxidation of the conductor layer 14. The oxidizing agent contained in the second polishing composition is preferably hydrogen peroxide in order to reduce metal contamination of the polishing object derived from the oxidizing agent.

  When the content of the oxidizing agent in the second polishing composition is less than 0.3 g / L, more specifically when it is less than 1.5 g / L, more specifically when it is less than 3 g / L, The ability of the second polishing composition to polish the conductor layer 14 is not significantly improved. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the content of the oxidizing agent in the second polishing composition is preferably 0.3 g / L or more, more preferably 1.5 g. / L or more, most preferably 3 g / L or more. On the other hand, when the content of the oxidizing agent in the second polishing composition is more than 30 g / L, more specifically more than 15 g / L, more specifically more than 10 g / L, the conductor layer There is a possibility that dishing is likely to occur because the ability of the second polishing composition to polish 14 becomes too high. Therefore, in order to suppress the occurrence of dishing, the content of the oxidizing agent in the second polishing composition is preferably 30 g / L or less, more preferably 15 g / L or less, and most preferably 10 g / L. It is as follows.

  The etching agent in the second polishing composition has an action of etching the object to be polished, and contributes to an improvement in the ability of the second polishing composition to polish the conductor layer 14 through etching of the conductor layer 14. The etching agent contained in the second polishing composition may be, for example, an α-amino acid such as glycine, alanine, or valine. Among them, in order to obtain a higher polishing rate for the conductor layer 14, Glycine is preferred.

  When the content of the etching agent in the second polishing composition is less than 0.5 g / L, more specifically less than 1 g / L, more specifically less than 3 g / L, the conductor layer The ability of the second polishing composition to polish 14 is not significantly improved. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the content of the etching agent in the second polishing composition is preferably 0.5 g / L or more, more preferably 1 g / L. As mentioned above, Most preferably, it is 3 g / L or more. On the other hand, when the content of the etching agent in the second polishing composition is more than 50 g / L, more specifically more than 30 g / L, more specifically more than 10 g / L, the conductor layer There is a possibility that dishing is likely to occur because the ability of the second polishing composition to polish 14 becomes too high. Therefore, in order to suppress the occurrence of dishing, the content of the etching agent in the second polishing composition is preferably 50 g / L or less, more preferably 30 g / L or less, and most preferably 10 g / L. It is as follows.

  The abrasive grains in the second polishing composition play a role of mechanically polishing the object to be polished, and contribute to an improvement in the ability of the second polishing composition to polish the conductor layer 14. The abrasive grains contained in the second polishing composition may be, for example, silica such as calcined silica, fumed silica, colloidal silica, or alumina such as colloidal alumina. In order to reduce surface defects of the polished object after polishing, silica is preferable, and colloidal silica is particularly preferable among them.

  When the content of the abrasive grains in the second polishing composition is less than 0.01 g / L, more specifically less than 0.05 g / L, and more specifically less than 0.1 g / L. However, the ability of the second polishing composition to polish the conductor layer 14 is not significantly improved. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the content of abrasive grains in the second polishing composition is preferably 0.01 g / L or more, more preferably 0.05 g. / L or more, most preferably 0.1 g / L or more. On the other hand, when the content of the abrasive grains in the second polishing composition is more than 200 g / L, more specifically more than 20 g / L, more specifically more than 10 g / L, the conductor layer There is a possibility that dishing is likely to occur because the ability of the second polishing composition to polish 14 becomes too high. Therefore, in order to suppress the occurrence of dishing, the content of abrasive grains in the second polishing composition is preferably 200 g / L or less, more preferably 20 g / L or less, and most preferably 10 g / L. It is as follows.

  Abrasive grains having an average primary particle size of less than 1 nm have almost no ability to polish an object to be polished. Therefore, in order to obtain a high polishing rate, the average primary particle size of the abrasive grains contained in the second polishing composition is preferably 1 nm or more. On the other hand, when the average primary particle diameter of the abrasive grains contained in the second polishing composition is larger than 500 nm, the surface quality of the polished object after polishing is reduced due to an increase in surface roughness or generation of scratches. May be seen. Therefore, in order to maintain the surface quality of the object to be polished after polishing, it is preferable that the average primary particle diameter of the abrasive grains contained in the second polishing composition is 500 nm or less. The average primary particle diameter of the abrasive grains is calculated from the specific surface area of the abrasive grains measured by, for example, the BET method.

  In particular, when the abrasive grains contained in the second polishing composition are colloidal silica, the following can be said with respect to the average primary particle diameter of the colloidal silica contained in the second polishing composition as abrasive grains. That is, when the average primary particle diameter of colloidal silica contained in the second polishing composition as abrasive grains is smaller than 3 nm, more specifically, smaller than 6 nm, the second polishing composition for polishing the conductor layer 14. The ability of things is not improved so much. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the average primary particle diameter of the colloidal silica contained in the second polishing composition as abrasive grains is preferably 3 nm or more, more preferably 6 nm. That's it. On the other hand, when the average primary particle diameter of the colloidal silica contained in the second polishing composition as abrasive grains is larger than 200 nm, more specifically larger than 100 nm, more specifically larger than 50 nm, colloidal silica is used. There is a risk that the sedimentation of the water is likely to occur. Therefore, in order to prevent the colloidal silica from settling, the average primary particle diameter of the colloidal silica contained in the second polishing composition as abrasive grains is preferably 200 nm or less, more preferably 100 nm or less, and most preferably 50 nm. It is as follows.

  When the pH of the second polishing composition is less than 8, there is a practical problem because a high polishing rate for the conductor layer 14 cannot be obtained or the abrasive grains in the second polishing composition cause aggregation. is there. Therefore, it is essential that the pH of the second polishing composition is 8 or more. On the other hand, if the pH of the second polishing composition is too high, the abrasive grains in the second polishing composition may be dissolved. Therefore, in order to prevent dissolution of the abrasive grains, the pH of the second polishing composition is preferably 13 or less, more preferably 11 or less.

<< 3rd polishing composition >>
The third polishing composition is produced so as to have a pH of 7 or more by mixing specific tolyltriazole having a six-membered ring skeleton, a water-soluble polymer, an oxidizing agent, abrasive grains, and water. Therefore, the third polishing composition substantially comprises a specific triazole having a six-membered ring skeleton, a water-soluble polymer, an oxidizing agent, abrasive grains, and water.

  Triazole in the third polishing composition has a hydrophobic functional group in the six-membered ring skeleton, and plays a role as a protective film forming agent having an action of forming a protective film on the surface of the polishing object. This triazole suppresses the occurrence of dishing (see FIG. 2B) by forming a protective film on the surface of the conductor layer 14 and suppressing the inner portion of the conductor layer 14 from being excessively removed.

  In order to obtain a higher protective film forming action, the hydrophobic functional group of the triazole 6-membered ring skeleton contained in the third polishing composition is preferably an alkyl group, more preferably a methyl group. In other words, the triazole contained in the third polishing composition is preferably tolyltriazole.

  Triazole having a six-membered ring skeleton having a hydrophobic functional group is more likely to retain organic residue on the surface of the object to be polished after polishing than a triazole having a six-membered ring skeleton having no functional group (for example, benzotriazole). There is little possibility of inviting. This is because the triazole having a six-membered ring skeleton having a hydrophobic functional group has a stronger action of forming a protective film on the surface of the conductor layer 14 than the triazole having a six-membered ring skeleton having no functional group. This is because a protective film sufficient to suppress excessive polishing of the conductor layer 14 is formed on the surface of the conductor layer 14 with a small amount of addition.

  When the content of triazole having a hydrophobic functional group in the six-membered ring skeleton in the third polishing composition is less than 0.1 g / L, more specifically less than 0.3 g / L, more specifically When the amount is less than 0.5 g / L, there is a possibility that a protective film sufficient to suppress excessive polishing of the conductor layer 14 is not formed on the surface of the conductor layer 14. As a result, the occurrence of dishing may not be significantly suppressed. Therefore, in order to strongly suppress the occurrence of dishing, the content of triazole having a hydrophobic functional group in the six-membered ring skeleton in the third polishing composition is preferably 0.1 g / L or more, Preferably it is 0.3 g / L or more, most preferably 0.5 g / L or more. On the other hand, when the content of triazole having a hydrophobic functional group in the six-membered ring skeleton in the third polishing composition is more than 3 g / L, as in the case of using benzotriazole, it is derived from triazole. Organic residue tends to remain on the surface of the polished object as a foreign substance. Therefore, it is essential that the content of triazole having a hydrophobic functional group in the six-membered ring skeleton in the third polishing composition is 3 g / L or less. When the content of triazole having a hydrophobic functional group in the six-membered ring skeleton in the third polishing composition is more than 2 g / L, more specifically, more than 1.5 g / L, the conductor Since the protective film is excessively formed on the surface of the layer 14, the polishing of the conductor layer 14 may be suppressed too much. Therefore, in order to maintain an appropriate polishing rate for the conductor layer 14, the content of the triazole having a hydrophobic functional group in the six-membered ring skeleton in the third polishing composition is preferably 2 g / L or less. More preferably, it is 1.5 g / L or less.

  The water-soluble polymer in the third polishing composition is blended in order to improve the ability of the third polishing composition to polish the insulator layer 12. In order to obtain a higher polishing rate with respect to the insulator layer 12, the water-soluble polymer contained in the third polishing composition is preferably a polysaccharide, a cellulose derivative, or polyvinyl alcohol, and more preferably among them. Is pullulan, hydroxyethyl cellulose, carboxymethyl cellulose or polyvinyl alcohol. Polyammonium acrylate is not preferable because it may cause dishing.

  When the content of the water-soluble polymer in the third polishing composition is less than 0.01 g / L, more specifically less than 0.1 g / L, more specifically less than 1 g / L. However, the ability of the third polishing composition to polish the insulator layer 12 is not significantly improved. In addition, there is a risk of causing a phenomenon called fang (see FIG. 2B) in which the level of the upper surface of the barrier layer 13 and the insulating layer 12 adjacent to the barrier layer 13 is lowered. Therefore, in order to obtain a higher polishing rate with respect to the insulator layer 12 and suppress the occurrence of fangs, the content of the water-soluble polymer in the third polishing composition is 0.01 g / L or more. More preferably, it is 0.1 g / L or more, and most preferably 1 g / L or more. On the other hand, if the content of the water-soluble polymer in the third polishing composition is more than 100 g / L, more specifically more than 50 g / L, more specifically more than 10 g / L, There is a possibility that the ability of the third polishing composition to polish the barrier layer 13 may decrease. Therefore, in order to obtain a higher polishing rate for the barrier layer 13, the content of the water-soluble polymer in the third polishing composition is preferably 100 g / L or less, more preferably 50 g / L. Hereinafter, it is most preferably 10 g / L or less.

  The oxidizing agent in the third polishing composition has an action of oxidizing the object to be polished, and the third polishing composition polishes the barrier layer 13 and the conductor layer 14 through oxidation of the barrier layer 13 and the conductor layer 14. Contributes to the improvement of ability. In order to obtain a higher polishing rate for the barrier layer 13 and the conductor layer 14, the oxidizing agent contained in the third polishing composition is preferably hydrogen peroxide.

  When the content of the oxidizing agent in the third polishing composition is less than 0.1 g / L, more specifically less than 0.3 g / L, and more specifically less than 0.5 g / L. However, the ability of the third polishing composition to polish the barrier layer 13 and the conductor layer 14 is not significantly improved. As a result, there is a possibility of causing a phenomenon called reverse dishing (see FIG. 2C) in which the portion of the conductor layer 14 to be removed remains without being removed and the upper surface of the conductor layer 14 protrudes. Therefore, in order to suppress the occurrence of reverse dishing by obtaining a higher polishing rate for the barrier layer 13 and the conductor layer 14, the content of the oxidizing agent in the third polishing composition is 0.1 g / L. Preferably, it is 0.3 g / L or more, and most preferably 0.5 g / L or more. On the other hand, when the content of the oxidizing agent in the third polishing composition is more than 6 g / L, more specifically more than 5 g / L, more specifically more than 4 g / L, the conductor layer There is a possibility that an oxide layer is excessively formed on the surface of 14. As a result, the portion of the conductor layer 14 to be removed may remain without being removed, resulting in the occurrence of reverse dishing. Therefore, in order to suppress the occurrence of reverse dishing, the content of the oxidizing agent in the third polishing composition is preferably 6 g / L or less, more preferably 5 g / L or less, and most preferably 4 g / L. L or less.

  The abrasive grains in the third polishing composition play a role of mechanically polishing the object to be polished, and contribute to an improvement in the ability of the third polishing composition to polish the conductor layer 14. The abrasive grains contained in the third polishing composition may be, for example, silica such as calcined pulverized silica, fumed silica, colloidal silica, or alumina such as colloidal alumina. In order to reduce surface defects of the polished object after polishing, silica is preferable, and colloidal silica is particularly preferable among them.

  When the content of abrasive grains in the third polishing composition is less than 30 g / L, more specifically less than 50 g / L, more specifically less than 80 g / L, the insulator layer 12 The ability of the third polishing composition to polish the barrier layer 13 and the conductor layer 14 is not so improved. Therefore, in order to obtain a higher polishing rate for the insulator layer 12, the barrier layer 13, and the conductor layer 14, the content of abrasive grains in the third polishing composition is preferably 30 g / L or more. More preferably, it is 50 g / L or more, and most preferably 80 g / L or more. On the other hand, when the content of the abrasive grains in the third polishing composition is more than 300 g / L, further more than 200 g / L, more specifically more than 160 g / L, further polishing. Little improvement in speed is obtained. Therefore, the content of abrasive grains in the third polishing composition is preferably 300 g / L or less, more preferably 200 g / L or less, and most preferably 160 g / L or less.

  Abrasive grains having an average primary particle diameter of less than 10 nm have almost no ability to polish an object to be polished. Therefore, in order to obtain a high polishing rate, it is preferable that the average primary particle diameter of the abrasive grains contained in the polishing composition is 10 nm or more. On the other hand, when the average primary particle diameter of the abrasive grains is larger than 500 nm, the surface quality of the polished object after polishing may be reduced due to an increase in surface roughness or generation of scratches. Therefore, in order to maintain the surface quality of the object to be polished after polishing, it is preferable that the average primary particle diameter of the abrasive grains contained in the polishing composition is 500 nm or less. The average primary particle diameter of the abrasive grains is calculated from the specific surface area of the abrasive grains measured by, for example, the BET method.

  In particular, when the abrasive grains contained in the third polishing composition are colloidal silica, the following can be said with respect to the average primary particle diameter of the colloidal silica contained in the third polishing composition as abrasive grains. That is, when the average primary particle diameter of the colloidal silica contained in the third polishing composition as abrasive grains is smaller than 10 nm, more specifically smaller than 15 nm, more specifically smaller than 20 nm, the insulator The ability of the third polishing composition to polish the layer 12, the barrier layer 13, and the conductor layer 14 is not significantly improved. Therefore, in order to obtain a higher polishing rate for the insulator layer 12, the barrier layer 13, and the conductor layer 14, the average primary particle diameter of colloidal silica contained in the third polishing composition as abrasive grains is 10 nm or more. Preferably, it is 15 nm or more, and most preferably 20 nm or more. On the other hand, when the average primary particle diameter of the colloidal silica contained in the third polishing composition as abrasive grains is larger than 100 nm, more specifically larger than 70 nm, more specifically larger than 60 nm, colloidal silica is used. Since it becomes easy to settle, there exists a possibility that the storage stability of the 3rd polishing composition may fall. Therefore, in order to prevent colloidal silica from settling, the average primary particle diameter of colloidal silica contained in the third polishing composition as abrasive grains is preferably 100 nm or less, more preferably 70 nm or less, and most preferably 60 nm. It is as follows.

  When the pH of the third polishing composition is less than 7, the ability of the third polishing composition to polish the barrier layer 13 is insufficient, or the abrasive grains in the third polishing composition cause aggregation. Reverse dishing may occur, which hinders practical use. Therefore, it is essential that the pH of the third polishing composition is 7 or more. However, even if the pH is 7 or more, the above-mentioned adverse effects tend to occur as the pH decreases. Therefore, the pH of the third polishing composition is preferably 7.5 or more. On the other hand, if the pH of the third polishing composition is too high, the abrasive grains in the third polishing composition may be dissolved. Accordingly, in order to prevent dissolution of the abrasive grains, the pH of the third polishing composition is preferably 13 or less, more preferably 11 or less.

According to the present embodiment, the following advantages can be obtained.
In the first polishing composition used in the first preliminary polishing step, the first polishing composition is used to polish the conductor layer 14 due to the mixing of the second or third polishing composition into the first polishing composition. 1 At least 1 type of compound chosen from the polysaccharide and polyvinyl alcohol which have the effect | action which suppresses that the capability of 1 polishing composition falls is contained. Therefore, even if the 2nd or 3rd polishing composition mixes in the 1st polishing composition, the fall of the capability of the 1st polishing composition which grind | polishes the conductor layer 14 is suppressed. Therefore, according to the present embodiment, the outer portion of the conductor layer 14 can be efficiently removed in the first preliminary polishing step.

  In addition to at least one compound selected from benzotriazole and benzotriazole derivatives, the second polishing composition used in the second preliminary polishing step is used as a protective film forming agent that functions to suppress the occurrence of dishing. At least one compound selected from the compounds represented by general formula (1) and general formula (2) is included. Therefore, according to the second polishing composition, although it contains benzotriazole as a protective film forming agent, it contains at least one compound selected from the compounds represented by general formula (1) and general formula (2). The occurrence of dishing can be more strongly suppressed as compared with conventional polishing compositions that do not. Therefore, according to the present embodiment, the outer portion of the conductor layer 14 can be removed while suppressing the occurrence of dishing in the second preliminary polishing step.

  -The third polishing composition used in the final polishing step contains, as a protective film forming agent, a triazole having a hydrophobic functional group on a 6-membered ring skeleton of 3 g or less per liter of the third polishing composition. . Therefore, unlike the conventional polishing composition containing benzotriazole as the protective film forming agent, a large amount of organic residue derived from the protective film forming agent does not remain as foreign matter on the surface of the polished object after polishing. Therefore, according to the present embodiment, in the final polishing step, at least the outer portion of the conductor layer 14 and the barrier while suppressing the organic substance residue derived from the protective film forming agent from remaining on the surface of the polished object as a foreign substance. Removal of the outer portion of layer 13 can be performed.

The embodiment may be modified as follows.
-An etching agent may be added to the first polishing composition. When the etching agent is added to the first polishing composition, the conductor layer 14 is etched by the action of the etching agent, thereby improving the ability of the first polishing composition to polish the conductor layer 14. The etching agent added to the first polishing composition is preferably a compound selected from organic acids including α-amino acids, more preferably, in order to obtain a higher polishing rate for the conductor layer 14. Glycine or α-alanine. The α-amino acid may be a neutral amino acid such as glycine, alanine, valine, leucine, isoleucine, alloisoleucine, serine, threonine, allothreonine, cysteine, methionine, phenylalanine, tryptophan, tyrosine, proline and cystine, or arginine and histidine. May be basic amino acids, and may be acidic amino acids such as glutamic acid and aspartic acid. Organic acids other than α-amino acids are oxalic acid, citric acid, succinic acid, maleic acid, tartaric acid, 2-quinolinecarboxylic acid (quinaldic acid), 2-pyridinecarboxylic acid, 2,6-pyridinecarboxylic acid and quinonic acid. Either may be sufficient.

  When the content of the etching agent in the first polishing composition is less than 0.01% by mass, and more specifically, less than 0.1% by mass, the first polishing composition for polishing the conductor layer 14 is used. The ability of things is not improved so much. Therefore, in order to obtain a higher polishing rate with respect to the conductor layer 14, the content of the etching agent in the first polishing composition is preferably 0.01% by mass or more, more preferably 0.1%. It is at least mass%. On the other hand, when the content of the etching agent in the first polishing composition is more than 20% by mass, more specifically, when it is more than 10% by mass, a large amount of etching agent is required, which is uneconomical. is there. Therefore, from an economical viewpoint, the content of the etching agent in the first polishing composition is preferably 10% by mass or less, and more preferably 5% by mass or less.

  A protective film forming agent may be added to the first polishing composition. When a protective film forming agent is added to the first polishing composition, a protective film is formed on the surface of the conductor layer 14 by the action of the protective film forming agent, so that surface defects (surface roughness and surface roughness) of the polished object after polishing are formed. Pits) are reduced. The protective film forming agent added to the first polishing composition is preferably a compound selected from triazole, imidazole, and derivatives thereof in order to greatly reduce the surface defects of the polished object after polishing, More preferred are compounds selected from benzotriazole and its derivatives.

  When the content of the protective film forming agent in the first polishing composition is less than 0.0001% by mass, the surface defects of the polished object after polishing are not significantly reduced. Therefore, in order to greatly reduce the surface defects of the polished object after polishing, the content of the protective film forming agent in the first polishing composition is preferably 0.0001% by mass or more. On the other hand, when the content of the protective film forming agent in the first polishing composition is more than 0.02% by mass, and more specifically, more than 0.01% by mass, When the second or third polishing composition is mixed in, the ability of the first polishing composition to polish the conductor layer 14 may be greatly reduced. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the content of the etching agent in the first polishing composition is preferably 0.02% by mass or less, more preferably 0.01%. It is below mass%.

  -An oxidizing agent may be added to the first polishing composition. When the oxidizing agent is added to the first polishing composition, the conductor layer 14 is oxidized by the action of the oxidizing agent, thereby improving the ability of the first polishing composition to polish the conductor layer 14. The oxidizing agent added to the first polishing composition may be any of hydrogen peroxide, persulfuric acid, periodic acid, perchloric acid, peracetic acid, performic acid, nitric acid, or a salt thereof. However, in order to reduce metal contamination of the polishing object derived from the oxidizing agent, the oxidizing agent added to the first polishing composition is preferably hydrogen peroxide.

  When the content of the oxidizing agent in the first polishing composition is less than 0.1% by mass, and more specifically, less than 1% by mass, the first polishing composition for polishing the conductor layer 14 is used. Ability is not improved so much. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the content of the oxidizing agent in the first polishing composition is preferably 0.1% by mass or more, more preferably 1% by mass. That's it. On the other hand, when the content of the oxidizing agent in the first polishing composition is more than 10% by mass, more specifically, when it is more than 5% by mass, a large amount of oxidizing agent is required, which is uneconomical. is there. Therefore, from an economic viewpoint, the content of the oxidizing agent in the first polishing composition is preferably 10% by mass or less, more preferably 5% by mass or less.

The first polishing composition may be prepared by diluting the concentrated stock solution before use.
-You may add well-known additives, such as antiseptic | preservative and an antifoamer, to the 1st polishing composition as needed.

  -You may omit the abrasive grain contained in the 2nd polishing composition. Even in this case, it is possible to ensure the ability of the second polishing composition to polish the conductor layer 14 by the action of the etching agent and the oxidizing agent contained in the second polishing composition. However, in order to obtain a higher polishing rate for the conductor layer 14, the second polishing composition preferably contains abrasive grains.

  -A compound (nonionic surfactant) represented by the following general formula (3) may be added to the second polishing composition. When the compound represented by the general formula (3) is added to the second polishing composition, the ability of the second polishing composition to polish the conductor layer 14 is improved. The compound represented by the general formula (3) has an action of forming a protective film on the surface of the object to be polished, like the compounds represented by the general formula (1) and the general formula (2). The protective film made of the compound represented by 3) has a lower protective effect than the protective film made of the compounds represented by the general formulas (1) and (2). Therefore, when the compound represented by the general formula (3) is added to the second polishing composition, it is represented by the general formula (1) or the general formula (2) in the case of the second polishing composition of the embodiment. A protective film having a relatively low protective effect by the compound represented by the general formula (3) is partially formed where a protective film having a relatively high protective action by the compound to be formed is formed. The above is considered to be the reason why the ability of the second polishing composition to polish the conductor layer 14 is improved when the compound represented by the general formula (3) is added to the second polishing composition. In order to obtain a higher polishing rate for the conductor layer 14, the compound represented by the general formula (3) contained in the second polishing composition is a polyoxyethylene alkyl ether such as polyoxyethylene lauryl ether. It is preferable that

ROR '(3)
In the formula (3), R represents an alkyl group or an alkylphenyl group, and R ′ represents a polyoxyethylene group or a polyoxypropylene group.

  When the content of the compound represented by the general formula (3) in the second polishing composition is more than 50 g / L, further more than 10 g / L, and more more than 5 g / L. In some cases, the dishing suppression action by the compounds represented by the general formula (1) and the general formula (2) may be weakened, and as a result, dishing may easily occur. In addition, the ability of the second polishing composition to polish the conductor layer 14 may decrease instead. Therefore, in order to avoid such harmful effects, the content of the compound represented by the general formula (3) in the second polishing composition is preferably 50 g / L or less, more preferably 10 g / L or less. Most preferably, it is 5 g / L or less.

  When the molecular weight of the compound represented by the general formula (3) contained in the second polishing composition is less than 300, more specifically less than 400, more specifically less than 500, the conductor layer The ability of the second polishing composition to polish 14 is not significantly improved. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the molecular weight of the compound represented by the general formula (3) contained in the second polishing composition is preferably 300 or more, more preferably. Is 400 or more, most preferably 500 or more. On the other hand, the compound represented by the general formula (3) becomes difficult to dissolve in water when the molecular weight is larger than 1500, more specifically, more than 1200, and more specifically more than 1000. In addition, when the molecular weight of the compound represented by the general formula (3) is so large, the ability of the second polishing composition to polish the conductor layer 14 may decrease instead. Therefore, in order to avoid such harmful effects, the molecular weight of the compound represented by the general formula (3) contained in the second polishing composition is preferably 1500 or less, more preferably 1200 or less, and most preferably 1000. It is as follows.

  When the HLB value of the compound represented by the general formula (3) contained in the second polishing composition is smaller than 13, more specifically, smaller than 14, the second polishing abrasive for polishing the conductor layer 14 is used. The capacity of the composition is not significantly improved. Therefore, in order to obtain a higher polishing rate for the conductor layer 14, the HLB value of the compound represented by the general formula (3) contained in the second polishing composition is preferably 13 or more, Preferably it is 14 or more. On the other hand, when the HLB value of the compound represented by the general formula (3) contained in the second polishing composition is greater than 18, more specifically, greater than 17, the general formula (1) and the general formula There is a possibility that the dishing suppression action by the compound represented by (2) may be weakened, and as a result, dishing may easily occur. Therefore, in order to suppress dishing, the HLB value of the compound represented by the general formula (3) contained in the second polishing composition is preferably 18 or less, more preferably 17 or less. In addition, the HLB value of the compound represented by General formula (3) is calculated | required, for example by the Griffin method.

  -A pH adjuster can also be added to the 2nd polishing composition as needed. Any pH adjuster may be added to the second polishing composition. However, since the ability of the polishing composition to polish the conductor layer 14 is improved, an alkali metal hydroxide such as potassium hydroxide is used. Alkali such as ammonia is preferred.

-The second polishing composition may be prepared by diluting the concentrated stock solution before use. The concentration rate of the concentrated stock solution is preferably 3 times or less.
-You may add well-known additives, such as antiseptic | preservative and an antifoamer, to the 2nd polishing composition as needed.

  -A triazole having a six-membered ring skeleton having a hydrophilic functional group may be added to the third polishing composition. When a triazole having a six-membered ring skeleton having a hydrophilic functional group is added to the third polishing composition, the ability of the third polishing composition to polish the insulator layer 12 and the conductor layer 14 is improved. In order to obtain a higher polishing rate for the insulator layer 12 and the conductor layer 14, the hydrophilic functional group of the triazole 6-membered ring skeleton is preferably a carboxyl group or an amino group, more preferably a carboxyl group. It is a group. More specifically, the triazole having a six-membered ring skeleton having a hydrophilic functional group added to the third polishing composition is used to obtain a higher polishing rate for the insulator layer 12 and the conductor layer 14. Is preferably carboxybenzotriazole or aminobenzotriazole, more preferably carboxybenzotriazole.

  When the content of triazole having a six-membered ring skeleton having a hydrophilic functional group in the third polishing composition is more than 10 g / L, more specifically more than 7 g / L, more specifically, 5 g / L. In the case where the amount is more than the upper limit, the ability of the third polishing composition to polish the conductor layer 14 is too high, and dishing is likely to occur. Moreover, since the capability of the 3rd polishing composition which grind | polishes the insulator layer 12 is too high, there exists a possibility that it may become easy to generate | occur | produce a fang. Therefore, in order to suppress the occurrence of dishing and fangs, the content of triazole having a six-membered ring skeleton having a hydrophilic functional group in the third polishing composition is preferably 10 g / L or less. Preferably it is 7 g / L or less, Most preferably, it is 5 g / L or less.

  -A pH adjuster can also be added to the 3rd polishing composition as needed. Any pH adjuster may be added to the third polishing composition, but since the ability of the polishing composition to polish the barrier layer 13 is improved, an alkali metal hydroxide such as potassium hydroxide is used. Alkali such as ammonia is preferred.

  A triazole having a six-membered ring skeleton having no functional group such as benzotriazole or 1- (2 ′, 3′-dihydroxypropyl) benzotriazole may be added to the third polishing composition. However, if a large amount of triazole having a six-membered ring skeleton having no functional group is contained in the third polishing composition, the organic residue derived from this triazole remains as a foreign substance on the surface of the polished object after polishing. It becomes easy. In order to more reliably prevent the organic residue from remaining on the surface of the polished object after polishing, the content of triazole having a six-membered ring skeleton having no functional group in the third polishing composition is the third polishing It is preferable that the total of the content of triazole having a six-membered ring skeleton having a hydrophobic functional group in the composition for use is 3 g / L or less.

  In the third polishing composition, 1,2,4-triazole, 1H-tetrazole or 5,5′-bi-1H-tetrazole diammonium salt may be added. However, if these azoles are contained in a large amount in the third polishing composition, many organic residues derived from these azoles remain as foreign substances on the surface of the polished object after polishing, or dishing may occur. There is a risk of doing. Therefore, in order to avoid such harmful effects, the content of 1,2,4-triazole, 1H-tetrazole or 5,5′-bi-1H-tetrazole diammonium salt in the third polishing composition is 1 g / L. It is preferable that it is less than.

The third polishing composition may be prepared by diluting the concentrated stock solution before use.
-You may add well-known additives, such as antiseptic | preservative and an antifoamer, to the 3rd polishing composition as needed.

Next, examples and comparative examples of the present invention will be described.
<< Examples 1-17 and Comparative Examples 1-20 >>
The 1st polishing composition of Examples 1-17 and Comparative Examples 1-20 is prepared by mixing water-soluble polymer or a compound replaced with it, an abrasive grain, an etching agent, benzotriazole, hydrogen peroxide, and water suitably. did. The details of the water-soluble polymer in each first polishing composition or a compound in place thereof, abrasive grains, etching agent, benzotriazole and hydrogen peroxide, and the pH of each first polishing composition are as shown in Table 1. .

  In the “polishing rate” column of Table 2, a copper blanket wafer having a diameter of 200 mm was polished under the polishing conditions shown in Table 3 using each of the first polishing compositions of Examples 1 to 17 and Comparative Examples 1 to 20. The polishing rate sometimes obtained is shown. The polishing rate was determined by dividing the difference in thickness of each wafer before and after polishing by the polishing time. For measuring the thickness of the wafer, a sheet resistance measuring machine “VR-120” manufactured by Kokusai Electric System Service Co., Ltd. was used. Specifically, the “additionless” column shows the polishing rate when the first polishing compositions of Examples 1 to 17 and Comparative Examples 1 to 20 were used as they were without adding any additives. In the “BTA 0.01% by mass” column, each first polishing composition to which benzotriazole was added so that the content of benzotriazole in the first polishing composition was 0.01% by mass was used. The polishing rate is shown. In the “BTA 0.02 mass%” column, each first polishing composition to which benzotriazole was added so that the content of benzotriazole in the first polishing composition was 0.02 mass% was used. The polishing rate is shown. In the “PVP 0.1 mass%” column, each first polishing composition to which polyvinyl pyrrolidone was added so that the content of polyvinyl pyrrolidone in the first polishing composition was 0.1 mass% was used. The polishing rate is shown. When each of the first polishing compositions to which lactic acid is added so that the content of lactic acid in the first polishing composition is 0.1% by mass is used in the “lactic acid 0.1% by mass” column The polishing rate is shown.

  In the “polishing rate maintenance ratio” column of Table 2, the values of the polishing rate when each of the first polishing compositions of Examples 1 to 17 and Comparative Examples 1 to 20 are used as they are, benzotriazole, polyvinylpyrrolidone or The polishing rate maintenance rate calculated | required by remove | dividing by the value of the grinding | polishing rate when using each 1st polishing composition to which lactic acid was added in the predetermined amount is shown. Specifically, the polishing rate maintenance rate when adding benzotriazole to each first polishing composition so that the content of benzotriazole in the first polishing composition is 0.01% by mass is expressed as “BTA0. .01 mass% "column. The polishing rate maintenance rate when adding benzotriazole to each first polishing composition so that the content of benzotriazole in the first polishing composition is 0.02% by mass is “BTA 0.02% by mass”. Shown in the column. The polishing rate maintenance rate when adding polyvinylpyrrolidone to each first polishing composition so that the content of polyvinylpyrrolidone in the first polishing composition is 0.1% by mass is “PVP 0.1% by mass”. Shown in the column. The column for “polishing lactic acid 0.1% by mass” indicates the polishing rate maintenance rate when lactic acid is added to each first polishing composition so that the content of lactic acid in the first polishing composition is 0.1% by mass. Shown in

表１の“水溶性高分子又はそれに代わる化合物”欄において、Ａ１はプルラン、Ａ２は平均分子量が１０万のポリビニルアルコール、Ａ３は平均分子量が１万のポリビニルアルコール、Ａ４は平均分子量が６００のポリエチレングリコール、Ａ５は平均分子量が２０００のポリエチレングリコール、Ａ６は平均分子量が１０００のポリアクリル酸、Ａ７はラウリル硫酸アンモニウムを表す。表１の“砥粒”欄において、Ｂ１は平均一次粒子径が３５ｎｍのコロイダルシリカ、Ｂ２は平均一次粒子径が１０ｎｍのコロイダルシリカ、Ｂ３は平均一次粒子径が３０ｎｍのフュームドシリカ、Ｂ４は平均一次粒子径が３０ｎｍのフュームドアルミナを表す。表１の“エッチング剤”欄において、Ｃ１はグリシン、Ｃ２はアラニン、Ｃ３はキナルジン酸を表す。

In the column of “Water-soluble polymer or an alternative compound” in Table 1, A1 is pullulan, A2 is polyvinyl alcohol having an average molecular weight of 100,000, A3 is polyvinyl alcohol having an average molecular weight of 10,000, and A4 is polyethylene having an average molecular weight of 600. Glycol, A5 represents polyethylene glycol having an average molecular weight of 2000, A6 represents polyacrylic acid having an average molecular weight of 1000, and A7 represents ammonium lauryl sulfate. In the “Abrasive” column of Table 1, B1 is colloidal silica having an average primary particle diameter of 35 nm, B2 is colloidal silica having an average primary particle diameter of 10 nm, B3 is fumed silica having an average primary particle diameter of 30 nm, and B4 is an average. This represents fumed alumina having a primary particle size of 30 nm. In the “Etching Agent” column of Table 1, C1 represents glycine, C2 represents alanine, and C3 represents quinaldic acid.

表２に示すように、実施例１〜１７の第１研磨用組成物では、比較例１〜２０の第１研磨用組成物と比べて、ベンゾトリアゾール、ポリビニルピロリドン又は乳酸を添加したときの研磨速度の低下の程度が小さかった。また実施例１〜１７の研磨用組成物は研磨速度に関しても実用上満足できるものであった。

As shown in Table 2, in the 1st polishing composition of Examples 1-17, compared with the 1st polishing composition of Comparative Examples 1-20, when benzotriazole, polyvinylpyrrolidone, or lactic acid is added, it polishes The degree of speed reduction was small. In addition, the polishing compositions of Examples 1 to 17 were practically satisfactory with respect to the polishing rate.

<< Examples 18 to 36 and Comparative Examples 21 to 32 >>
Benzotriazole, polyoxyethylene lauryl ether acetic acid or an alternative compound, polyoxyethylene lauryl ether, 31% aqueous solution of hydrogen peroxide, glycine, colloidal silica sol and pH adjuster are mixed appropriately and diluted with water as necessary. Thus, the second polishing compositions of Examples 18 to 36 and Comparative Examples 21 to 32 were prepared. Details of benzotriazole, polyoxyethylene lauryl ether acetic acid or an alternative compound, polyoxyethylene lauryl ether, 31% aqueous solution of hydrogen peroxide, glycine, colloidal silica and pH adjuster in each second polishing composition 2 The pH of the polishing composition is as shown in Table 4.

  In the “polishing rate” column of Table 4, a copper blanket wafer having a diameter of 200 mm was polished under the polishing conditions shown in Table 5 using the second polishing compositions of Examples 18 to 36 and Comparative Examples 21 to 32. The polishing rate sometimes obtained is shown. The polishing rate was determined by dividing the difference in thickness of each wafer before and after polishing by the polishing time. For measuring the thickness of the wafer, a sheet resistance measuring machine “VR-120” manufactured by Kokusai Electric System Service Co., Ltd. was used.

  In the "Dishing" column of Table 4, the dishing amount was measured with a copper pattern wafer (854 mask pattern) of SEMATEC, polished using each of the second polishing compositions of Examples 18 to 36 and Comparative Examples 21 to 32. The results are shown. Specifically, a copper pattern wafer manufactured by SEMATEC has a barrier layer made of tantalum and a copper conductor layer having a thickness of 10,000 mm on an insulating layer made of silicon dioxide having a trench, and has a depth of 5000 mm. Initial recesses on the top surface. Before polishing this copper pattern wafer with each of the second polishing compositions of Examples 18 to 36 and Comparative Examples 21 to 32, the first polishing composition of Example 1 was used to Pre-polishing was performed under the polishing conditions shown in Table 5 until the thickness reached 300 nm. Then, the same copper pattern wafer was grind | polished on the grinding | polishing conditions shown in Table 5 using each 2nd polishing composition of Examples 18-36 and Comparative Examples 21-32 until the upper surface of a barrier layer was exposed. Thereafter, using a profiler “HRP340” which is a contact surface measuring device manufactured by KLA-Tencor Corporation, the dishing amount was measured in each wafer region in which trenches having a width of 100 μm were formed in isolation.

  In the "dispersion stability" column of Table 4, the results of evaluating the dispersion stability of each of the second polishing compositions of Examples 18 to 36 and Comparative Examples 21 to 32 are shown. Specifically, the presence or absence of aggregation and sedimentation was observed in each of the second polishing compositions of Examples 18 to 36 and Comparative Examples 21 to 32 that were allowed to stand for 30 days in an 80 ° C. constant temperature bath. Based on this, the dispersion stability of each second polishing composition was evaluated. In the “dispersion stability” column, “◯” indicates that aggregation and sedimentation were not observed, and “x” indicates that aggregation or sedimentation was observed.

表４の“ポリオキシエチレンラウリルエーテル酢酸又はそれに代わる化合物”欄において、Ｂ１はポリオキシエチレンラウリルエーテル酢酸、Ｂ２はヤシ油脂肪酸サルコシントリエタノールアミン、Ｂ３はポリオキシエチレンラウリルエーテル硫酸アンモニウムを表す。表４の“ｐＨ調整剤”欄において、Ｇ１は水酸化カリウム、Ｇ２はアンモニア、Ｇ３はグリコール酸、Ｇ４は硫酸を表す。

In the column of “Polyoxyethylene lauryl ether acetic acid or an alternative compound” in Table 4, B1 represents polyoxyethylene lauryl ether acetic acid, B2 represents coconut oil fatty acid sarcosine triethanolamine, and B3 represents polyoxyethylene lauryl ether ammonium sulfate. In the “pH adjuster” column of Table 4, G1 represents potassium hydroxide, G2 represents ammonia, G3 represents glycolic acid, and G4 represents sulfuric acid.

  The polyoxyethylene lauryl ether acetic acid used in Examples and Comparative Examples has a molecular weight of 441, the number of repeating units in the polyoxyethylene group is 2.5, and the HLB value is 12.2. The palm oil fatty acid sarcosine triethanolamine used in the comparative example has a molecular weight of 444 and an HLB value of 9.8. The polyoxyethylene lauryl ether ammonium sulfate used in the comparative example has a molecular weight of 374.5, the number of repeating units in the polyoxyethylene group is 2, and the HLB value is 10.9. The polyoxyethylene lauryl ether used in the examples has a molecular weight of 802 and an HLB value of 15.8.

表４に示すように、実施例１８〜３６の第２研磨用組成物では、ディッシングについては１００ｎｍ以下、研磨速度については１００ｎｍ／分以上とディッシング及び研磨速度に関して実用上満足できる結果が得られた。また実施例１８〜３６の第２研磨用組成物は保存安定性に関しても実用上満足できるものであった。それに対し、比較例２１〜３２の第２研磨用組成物では、研磨速度及びディッシングの少なくともいずれか一方に関して良好な結果が得られなかった。

As shown in Table 4, in the second polishing compositions of Examples 18 to 36, the dishing was 100 nm or less, the polishing rate was 100 nm / min or more, and practically satisfactory results were obtained with respect to the dishing and polishing rate. . In addition, the second polishing compositions of Examples 18 to 36 were satisfactory in terms of storage stability. On the other hand, in the second polishing composition of Comparative Examples 21 to 32, good results were not obtained with respect to at least one of the polishing rate and dishing.

<< Examples 37 to 64 and Comparative Examples 33 to 42 >>
The third polishing composition of Examples 37 to 64 and Comparative Examples 33 to 42 are appropriately mixed with triazole, water-soluble polymer, hydrogen peroxide, colloidal silica sol and pH adjuster and diluted with water as necessary. A product was prepared. Table 6 shows the details of triazole, water-soluble polymer, hydrogen peroxide, colloidal silica and pH adjuster in each third polishing composition, and the pH of each third polishing composition.

  In the “Copper polishing rate” column, “Tantalum polishing rate” column and “Silicon dioxide polishing rate” column of Table 7, the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42 were used. The polishing rate obtained when each 200 mm diameter copper blanket wafer, tantalum blanket wafer and silicon dioxide (TEOS) blanket wafer is polished under the polishing conditions shown in Table 8 is shown. The polishing rate was determined by dividing the difference in thickness of each wafer before and after polishing by the polishing time. To measure the thickness of copper blanket wafers and tantalum blanket wafers, use the sheet resistance measuring instrument “VR-120” of Kokusai Electric System Service Co., Ltd., and measure the thickness of silicon dioxide blanket wafers by KLA-Tencor Corporation. The equipment “ASET-F5x” was used. The polishing rate of each third polishing composition for the copper blanket wafer is shown in the “copper polishing rate” column, the polishing rate of each third polishing composition for the tantalum blanket wafer is shown in the “tantalum polishing rate” column, and silicon dioxide. The polishing rate of each third polishing composition for the blanket wafer is shown in the “Silicon dioxide polishing rate” column.

  The “pot life” column of Table 7 shows the results of evaluating the pot life of the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42. Specifically, the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42 immediately after preparation, and Examples 37 to 64 and Comparative Example 33 after being stored for a while in a sealed container after adjustment. A copper blanket wafer, a tantalum blanket wafer, and a silicon dioxide blanket wafer were polished under the polishing conditions shown in Table 8 using the third polishing composition of .about.42, respectively. Then, the polishing rate of the third polishing composition with respect to the wafer is calculated from the difference in thickness of each wafer before and after polishing, and the polishing rate with the third polishing composition immediately after preparation and the third after a while after preparation. Based on the comparison of the polishing rate in the polishing composition, the pot life of each third polishing composition was evaluated. In the “pot life” column, ◯ indicates that a polishing rate exceeding 80% immediately after preparation was obtained even after the second half of the adjustment, and Δ indicates that immediately after preparation three months after preparation. A polishing rate exceeding 80% was obtained, but after the second half of the adjustment, only less than 80% of the polishing rate immediately after the preparation was obtained. It shows that only a polishing rate of less than 80% was obtained.

  In the “Corrosive” column of Table 7, the results of evaluating the strength of the corrosive action of each of the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42 are shown. Specifically, first, a polishing pattern shown in Table 3 was applied to a copper pattern wafer (854 mask pattern) manufactured by SEMATEC until the thickness of the conductor layer reached 300 nm using the first polishing composition of Example 1. Further, the second polishing composition of Example 28 was used for polishing under the polishing conditions shown in Table 5 until the upper surface of the barrier layer was exposed. Thereafter, the same copper pattern wafer was further polished under the polishing conditions shown in Table 8 using the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42. Then, using a differential interference microscope “OPTIPHOTO300” of Nikon Corporation, the presence or absence of corrosion of the wiring on the polished wafer surface was observed, and the strength of the third polishing composition was determined based on the observation result. evaluated. In the “Corrosive” column, ○ indicates that corrosion was observed, and Δ indicates that corrosion was slightly recognized.

  In the “Dishing” column of Table 7, dishing occurs when a SEMATEC copper pattern wafer (854 mask pattern) is polished using the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42. The result of evaluating how much it is improved is shown. Specifically, as described above, after polishing the copper pattern wafer using the first polishing composition of Example 1 and the second polishing composition of Example 28, Examples 37 to 64 and Comparative Examples The same copper pattern wafer was grind | polished on the grinding | polishing conditions shown in Table 8 using the 3rd polishing composition of 33-42. Before and after polishing with the third polishing composition, a profiler “HRP340” was used to measure the dishing amount in the region of the wafer in which trenches having a width of 100 μm were isolated. Based on a value obtained by subtracting the dishing amount after polishing using the third polishing composition from the dishing amount before polishing using the third polishing composition, dishing is performed by the third polishing composition. We evaluated how much it improved. In the “Dishing” column, ○ indicates that the value obtained by subtracting the dishing amount after polishing using the third polishing composition from the dishing amount before polishing using the third polishing composition is 20 nm or more. , Δ indicates 5 nm or more and less than 20 nm, and × indicates less than 5 nm.

  In the "Fang" column of Table 7, occurrence of fangs is generated in a copper pattern wafer (854 mask pattern) manufactured by SEMATEC that is polished using each of the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42. The result of evaluating the degree is shown. Specifically, as described above, after polishing the copper pattern wafer using the first polishing composition of Example 1 and the second polishing composition of Example 28, Examples 37 to 64 and Comparative Examples The same copper pattern wafer was grind | polished on the grinding | polishing conditions shown in Table 8 using the 3rd polishing composition of 33-42. Thereafter, the profiler “HRP340” was used to measure the amount of fang in each wafer region in which 100 μm-wide trenches were isolated, and the degree of fang generation was evaluated based on the measurement result. In the “Fang” column, ◯ indicates that the amount of fang is less than 5 nm, Δ indicates that it is 5 nm or more and less than 10 nm, and x indicates that it is 10 nm or more.

  In the column “Reverse dishing” in Table 7, reverse dishing was performed on a copper pattern wafer (854 mask pattern) of SEMATEC that was polished using the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42. The result of measuring the presence or absence of occurrence is shown. Specifically, first, a copper pattern wafer was polished using the first polishing composition of Example 1 under the polishing conditions shown in Table 3 until the thickness of the conductor layer reached 300 nm. Polishing was performed under the polishing conditions shown in Table 5 using the 24 second polishing composition until the upper surface of the barrier layer was exposed. Then, the same copper pattern wafer was finish-polished on the grinding | polishing conditions shown in Table 8 using the 3rd polishing composition of Examples 37-64 and Comparative Examples 33-42. After finishing polishing, the profiler “HRP340” was used to measure the presence or absence of reverse dishing in the region of the wafer in which trenches having a width of 100 μm were formed in isolation. In the “reverse dishing” column, “◯” indicates that reverse dishing has not occurred, and “x” indicates that reverse dishing has occurred.

  In the “Number of residual foreign matter” column of Table 7, foreign matter present on the surface of a copper blanket wafer having a diameter of 200 mm after polishing using the third polishing compositions of Examples 37 to 64 and Comparative Examples 33 to 42 The results of measuring the number of the are shown. Specifically, first, a copper blanket wafer was polished for 60 seconds under the polishing conditions shown in Table 8 using each third polishing composition, and then polished with a cleaning solution “MCX-SDR4” manufactured by Mitsubishi Chemical Corporation. The copper blanket wafer was cleaned. Thereafter, the number of foreign matters having a size of 0.2 μm or more present on the wafer surface was measured using a surface foreign matter inspection apparatus “Surfscan SP1TBI” manufactured by KLA-Tencor.

表６の“トリアゾール”欄において、Ａ１はトリルトリアゾール、Ａ２はベンゾトリアゾール、Ａ３は１，２，４−トリアゾール、Ｂ１はカルボキシベンゾトリアゾールを表す。表６の“水溶性高分子”欄において、Ｃ１はプルラン、Ｃ２はポリビニルアルコール、Ｃ３はヒドロキシエチルセルロース、Ｃ４はカルボキシメチルセルロース、Ｃ５はポリアクリル酸アンモニウムを表す。表６の“ｐＨ調整剤”欄において、Ｆ１はアンモニア、Ｆ２は水酸化カリウム、Ｆ３はリンゴ酸、Ｆ４はクエン酸を表す。

In the “triazole” column of Table 6, A1 represents tolyltriazole, A2 represents benzotriazole, A3 represents 1,2,4-triazole, and B1 represents carboxybenzotriazole. In the “water-soluble polymer” column of Table 6, C1 represents pullulan, C2 represents polyvinyl alcohol, C3 represents hydroxyethylcellulose, C4 represents carboxymethylcellulose, and C5 represents ammonium polyacrylate. In the “pH adjuster” column of Table 6, F1 represents ammonia, F2 represents potassium hydroxide, F3 represents malic acid, and F4 represents citric acid.

表７に示すように、実施例３７〜６４の第３研磨用組成物では、研磨後のウエハ表面の異物の個数を１０×１０^２個以下に抑えることができた。また、実施例３７〜６４の第３研磨用組成物は、研磨速度、ポットライフ、腐食性、ディッシング、ファング及び逆ディッシングに関しても実用上満足できるものであった。

As shown in Table 7, in the third polishing compositions of Examples 37 to 64, the number of foreign matters on the wafer surface after polishing could be suppressed to 10 × 10 ² or less. In addition, the third polishing compositions of Examples 37 to 64 were practically satisfactory with respect to the polishing rate, pot life, corrosivity, dishing, fang and reverse dishing.

The technical idea that can be grasped from the embodiment will be described below.
The polishing of the polishing object in the first preliminary polishing step is performed using another preliminary polishing composition containing at least one compound selected from polysaccharides and polyvinyl alcohol and abrasive grains. The method according to any one of claims 1 to 6.

  The polishing of the polishing object in the first preliminary polishing step is performed using another preliminary polishing composition containing at least one compound selected from polysaccharides and polyvinyl alcohol and abrasive grains. The method according to any one of claims 1 to 6, wherein at least one compound selected from a polysaccharide and polyvinyl alcohol contained in the preliminary polishing composition is pullulan.

(A)-(d) is sectional drawing of the grinding | polishing target object for demonstrating the formation method of the wiring of a semiconductor device. (A) is a sectional view of a polishing object for explaining dishing, (b) is a sectional view of a polishing object for explaining dishing and fang, and (c) is a polishing object for explaining reverse dishing. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Trench, 12 ... Insulator layer, 13 ... Barrier layer, 14 ... Conductor layer.

Claims (6)

A method for polishing an object to be polished, the polishing object comprising: an insulator layer having a trench; a barrier layer provided on the insulator layer; and a conductor layer provided on the barrier layer. Each of the barrier layer and the conductor layer has an inner portion located in the trench and an outer portion located outside the trench, the method comprising:
A preliminary polishing step of polishing the object to be polished in order to remove a part of the outer portion of the conductor layer and expose the upper surface of the outer portion of the barrier layer;
A final polishing step of polishing a polishing object from which a part of the outer portion of the conductor layer has been removed in order to remove at least the remainder of the outer portion of the conductor layer and the outer portion of the barrier layer, and the preliminary polishing step comprises ,
A first preliminary polishing step for polishing an object to be polished in order to remove most of the portion of the conductor layer to be removed in the preliminary polishing step;
A second preliminary polishing step of polishing a polishing object from which most of the portion of the conductor layer to be removed is removed in order to remove the remainder of the portion of the conductor layer to be removed;
The polishing of the object to be polished in the second preliminary polishing step is performed using a preliminary polishing composition containing a protective film forming agent, an oxidizing agent, and an etching agent, and the protective film forming agent Represents at least one compound selected from benzotriazole and benzotriazole derivatives, a general formula ROR′COOH and a general formula ROR′OPO ₃ H ₂ (R represents an alkyl group or an alkylphenyl group, R ′ represents a polyoxyethylene group; , Represents a polyoxypropylene group or a poly (oxyethylene / oxypropylene) group.), And the pH of the preliminary polishing composition is 8 or more. And how to. At least one compound selected from the compounds represented by the general formula ROR′COOH and the general formula ROR′OPO ₃ H ₂ contained in the preliminary polishing composition is polyoxyethylene alkyl ether acetic acid or polyoxyethylene alkyl phenyl ether phosphorus The method of claim 1 which is an acid.   The preliminary polishing composition further contains a compound represented by the general formula ROR ′ (R represents an alkyl group or an alkylphenyl group, and R ′ represents a polyoxyethylene group or a polyoxypropylene group). Item 3. The method according to Item 1 or 2.   The polishing of the polishing object in the final polishing step is performed using a final polishing composition containing a triazole having a six-membered ring skeleton, a water-soluble polymer, an oxidizing agent, and abrasive grains. The triazole has a hydrophobic functional group in a six-membered ring skeleton, the content of the triazole in the finish polishing composition is 3 g / L or less, and the pH of the finish polishing composition is 7 or more The method according to any one of claims 1 to 3. A method for polishing an object to be polished, the polishing object comprising: an insulator layer having a trench; a barrier layer provided on the insulator layer; and a conductor layer provided on the barrier layer. Each of the barrier layer and the conductor layer has an inner portion located in the trench and an outer portion located outside the trench, the method comprising:
A preliminary polishing step of polishing the object to be polished in order to remove a part of the outer portion of the conductor layer and expose the upper surface of the outer portion of the barrier layer;
A final polishing step of polishing a polishing object from which a part of the outer portion of the conductor layer has been removed in order to remove at least the remainder of the outer portion of the conductor layer and the outer portion of the barrier layer;
The polishing of the polishing object in the final polishing step is performed using a final polishing composition containing a triazole having a six-membered ring skeleton, a water-soluble polymer, an oxidizing agent, and abrasive grains. The triazole has a hydrophobic functional group in a six-membered ring skeleton, the content of the triazole in the finish polishing composition is 3 g / L or less, and the pH of the finish polishing composition is 7 or more A method characterized in that   The method according to claim 4 or 5, wherein the finish polishing composition further contains at least one of carboxybenzotriazole and aminobenzotriazole.

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