JP7380238B2 - Polishing composition and polishing method - Google Patents

Description

The present invention relates to a polishing composition and a polishing method, and particularly to a polishing composition for chemical mechanical polishing in the manufacture of semiconductor integrated circuits, and a polishing method using the polishing composition.

In recent years, as semiconductor integrated circuits have become more highly integrated and highly functional, the development of microfabrication techniques for miniaturizing and increasing the density of semiconductor elements has been progressing. Conventionally, in the manufacturing of semiconductor integrated circuit devices (hereinafter also referred to as semiconductor devices), in order to prevent problems such as unevenness (steps) on the layer surface exceeding the depth of focus of lithography and not being able to obtain sufficient resolution, 2. Description of the Related Art Interlayer insulating films, buried wiring, and the like are planarized using chemical mechanical polishing (hereinafter referred to as CMP).

Conventionally, copper and tungsten have been used for buried wiring, but copper has grain boundaries, which increases resistance and limits the ability to make wires thinner. There is also a limit to the thinning of tungsten wires. Therefore, the use of metals such as cobalt, ruthenium, and molybdenum, which have low resistance and can be made into thin wires, for embedded wiring is being used or is being considered.

In CMP related to wiring formation, there is a great need for new polishing compositions in response to changes in the metal material of buried wiring. Note that polishing compositions for CMP are required to perform polishing with extremely high precision compared to mere mechanical polishing compositions, and thus require very precise adjustment.

Among the metals that can be made into thin wires, polishing compositions for CMP are known for cobalt. For example, Patent Document 1 describes a pH-adjusted CMP slurry for cobalt that contains an inhibitor, an oxidizing agent, an abrasive, a complexing agent, and water in predetermined proportions, each of which is a specific compound. .

The oxidizing agent in the CMP slurry of Patent Document 1 is a component that is generally introduced in order to increase the processing speed in CMP of metal wiring constituting a semiconductor device. However, oxidizing agents cause corrosion of metal wiring and polishing equipment. Furthermore, the oxidizing agent is easily decomposed by a disproportionation reaction, and the concentration of the oxidizing agent in the polishing composition cannot be controlled at a constant level, which causes variations in processing speed and reduces the reproducibility of the polishing process. In addition, the oxidizing agent denatures the polishing stop layer (SiN, etc.) through oxidation, weakening its function as a polishing stop layer, and making it difficult to control polishing.

Furthermore, Non-Patent Document 1 discloses the use of sodium percarbonate as an oxidizing agent as a polishing composition for CMP for forming metal interconnects used in semiconductor devices with embedded interconnects using ruthenium or molybdenum. , there were problems such as slow polishing speed.

Special table 2014-509064 publication

M. C. Turk et al. Investigation of Percarbonate Based Slurry Chemistry for Controlling Galvanic Corrosion during CMP of Ruthenium, ECS J. Solid State Sci. Technol. 2013 volume 2, issue 5, P205-P213

The present invention relates to a composition used in CMP for forming wiring in a semiconductor integrated circuit device using metals such as cobalt, ruthenium, molybdenum, etc., which have low resistance and can be thinned, and in particular, these metals are used as embedded wiring. Provided is a polishing composition capable of polishing a metal layer at a high polishing rate without using an oxidizing agent, and a polishing method using the polishing composition, and further improves the polishing rate of a metal layer and an insulating film. Another object of the present invention is to provide a polishing composition and a polishing method that allow adjustment of the polishing composition.

The polishing composition of the present invention is characterized by containing a compound represented by the following formula (1), cerium oxide particles, and water.

In formula (1), R ¹ is S ^- , SR ¹¹ (R ¹¹ is a hydrocarbon group which may contain a hydrogen atom or a hetero atom), N ^- R ¹² (R ¹² is a hydrogen atom or a hetero atom). ), NR ¹³ R ¹⁴ (R ¹³ and R ¹⁴ are each independently a hydrocarbon group that may contain a hydrogen atom or a hetero atom, or are bonded to each other to form a heterocycle) ), or N=NR ¹⁵ (R ¹⁵ is a hydrocarbon group), and R ² is a hydrocarbon group which may contain a heteroatom. X ⁺ is a monovalent cation and n is 1 when R ¹ is S ⁻ or N ⁻ R ¹² and 0 otherwise.

In the polishing composition of the present invention, R ¹ in formula (1) is S ^- or SR ¹¹ , and R ² is NR ²³ R ²⁴ (R ²³ and R ²⁴ are each independently a hydrogen atom or ), N=NR ²⁵ (R ²⁵ is a hydrocarbon group) or OR ²⁶ (R ²⁶ is a hetero It is a hydrocarbon group which may contain an atom.) is preferable.

In the polishing composition of the present invention, R ¹ in formula (1) is N ^- R ¹² , NR ¹³ R ¹⁴ or N=NR ¹⁵ , and R ² is NR ⁴³ R ⁴⁴ (R ⁴³ and R ⁴⁴ is a hydrocarbon group which may each independently contain a hydrogen atom or a heteroatom, or a group which combines with each other to form a heterocycle.) or N=NR ⁴⁵ (R ⁴⁵ is a hydrocarbon group). ) is preferable.

The polishing composition of the present invention preferably has a pH of 2.0 to 11.0.

The content of the above-mentioned compound in the polishing composition of the present invention is preferably 0.0001% by mass or more and 10% by mass or less based on the total mass of the polishing composition.

It is preferable that the polishing composition of the present invention further contains abrasive grains.

The polishing method of the present invention is a method in which the polishing composition of the present invention is supplied to a polishing pad, the surface to be polished of a semiconductor integrated circuit device is brought into contact with the polishing pad, and polishing is performed by relative movement between the two. In this polishing method, the surface to be polished includes a metal containing at least one selected from cobalt, ruthenium, and molybdenum.

The polishing method of the present invention can be used, for example, in the production of a semiconductor integrated circuit device having a pattern in which buried metal interconnects and insulating layers containing at least one selected from cobalt, ruthenium, and molybdenum are alternately arranged. It is used in the method of polishing a metal layer made of the metal provided on the insulating layer so as to fill the groove using the polishing composition of the present invention.

According to the polishing composition and polishing method of the present invention, semiconductor integrated circuit devices using metals such as cobalt, ruthenium, molybdenum, etc., which have low resistance and can be made into thin wires, particularly those using these metals as embedded wiring, can be manufactured. In a composition used in CMP for forming wiring, a metal layer can be polished at a high polishing rate without using an oxidizing agent. When the present polishing composition does not contain an oxidizing agent, it is possible to polish a metal layer at a high polishing rate without causing corrosion of metal wiring or polishing equipment caused by such an oxidizing agent. Furthermore, when a polishing stop layer is used in the CMP for forming interconnections of the semiconductor integrated circuit device, well-controlled polishing is possible without weakening the function of the polishing stop layer. Furthermore, it is also possible to adjust the polishing speed of the metal layer and the insulating film.

FIG. 2 is a cross-sectional view of a semiconductor integrated circuit device schematically showing a polishing step (before polishing) when forming buried wiring by CMP. FIG. 2 is a cross-sectional view of a semiconductor integrated circuit device schematically showing a polishing step (after polishing) when forming buried wiring by CMP. 1 is a diagram showing an example of a polishing apparatus that can be used in the polishing method of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to the following embodiments, and other embodiments may also belong to the scope of the present invention as long as they meet the spirit of the present invention.

In this specification, the compound represented by formula (1) is referred to as compound (1). For compounds or groups represented by other formulas, the formula number is used as an abbreviation of the compound or group instead of the name of the compound or group.

In this specification, "~" representing a numerical range includes the upper and lower limits.

The polishing composition of the present invention (hereinafter also referred to as "the present polishing composition") is characterized by containing the compound (1) represented by the above formula (1) and water.

The present polishing composition is suitably used for polishing a metal layer used for forming embedded wiring in a semiconductor integrated circuit. The metal layer may be a metal layer that becomes a buried wiring, or may be a metal layer other than a buried wiring, such as a barrier layer used when forming a copper wiring. The polishing composition of the present invention is particularly suitable for polishing metal layers that become embedded wiring.

The metal layer is a metal (hereinafter also referred to as "metal M") containing at least one selected from cobalt (Co), ruthenium (Ru), and molybdenum (Mo). is preferred. Among these, the effect of the present invention is particularly remarkable when the metal M contains Ru. The metal M may contain one type each of Co, Ru, and Mo, or may contain two or more types. Further, metals other than Co, Ru, and Mo may be included. When the metal M includes a plurality of metals, it may be an alloy or a mixture.

The following explanation will focus on the case where it is applied to a semiconductor integrated circuit device having metal wiring made of metal M, but the polishing composition according to the present invention can also be used in other cases as long as it is used for polishing metal wiring. .

1 and 2 are cross-sectional views of a semiconductor integrated circuit device schematically shown in order to explain a polishing process when forming buried wiring by CMP. FIG. 1 shows the state before polishing, and FIG. 2 shows the state after polishing. The configuration of each member in these drawings is a typical configuration, and the present invention is not limited thereto.

In the semiconductor integrated circuit device 10 before polishing shown in FIG. 1, an insulating layer 2, a polishing stop layer 3, and a metal layer 4 made of metal M are formed in this order on a semiconductor substrate 1. The insulating layer 2 has a groove, and the polishing stop layer 3 is formed on the insulating layer 2 in a shape that follows the surface shape of the insulating layer 2. The metal layer 4 is formed on the polishing stop layer 3 to fill a groove.

FIG. 2 shows that the semiconductor integrated circuit device 10 before polishing shown in FIG. 1 is subjected to CMP using the present polishing composition to polish only the metal layer 4 (first polishing step), and then A semiconductor integrated circuit having a pattern in which embedded wiring 6 and insulating layer 2 are alternately arranged after polishing layer 4, polishing stop layer 3, and insulating layer 2 (second polishing step) to planarize the surface. FIG. 2 is a cross-sectional view of the circuit device 11. FIG.

By containing the compound (1), the polishing composition of the present invention can be used, for example, in CMP for forming wiring of a semiconductor integrated circuit device shown in FIGS. 1 and 2, without using an oxidizing agent. In particular, a metal layer made of a metal containing at least one selected from cobalt, ruthenium, and molybdenum can be polished at a high polishing rate.

According to the present polishing composition, a high polishing rate can be achieved in the first polishing step of polishing only the metal layer 4, and can contribute to improving production efficiency. Furthermore, in the second polishing step of polishing the metal layer 4, the polishing stop layer 3, and the insulating layer 2, the metal layer 4, the polishing stop layer 3, and the insulating layer 2 can be uniformly polished, and the surface to be polished is flat. Polishing with guaranteed properties is possible. According to this polishing composition, when an oxidizing agent is not used, the metal M constituting the buried wiring 6 obtained is hardly corroded, and a highly reliable semiconductor integrated circuit device 11 can be obtained. In addition, there are no problems such as corrosion of the polishing equipment. Note that details of the polishing method will be described later.

Hereinafter, each component contained in the polishing composition of the present invention and the pH will be explained. This polishing composition contains the compound (1), cerium oxide particles, and water as essential components. The present polishing composition may contain optional components such as a pH adjuster, abrasive grains, a rust preventive, and a dispersant.

<Compound (1)>
Compound (1) is represented by the following formula (1).

In formula (1), R ¹ is S ^- , SR ¹¹ (R ¹¹ is a hydrocarbon group which may contain a hydrogen atom or a hetero atom), N ^- R ¹² (R ¹² is a hydrogen atom or a hetero atom). ), NR ¹³ R ¹⁴ (R ¹³ and R ¹⁴ are each independently a hydrocarbon group that may contain a hydrogen atom or a hetero atom, or are bonded to each other to form a heterocycle) ), or N=NR ¹⁵ (R ¹⁵ is a hydrocarbon group), and R ² is a hydrocarbon group which may contain a heteroatom. X ⁺ is a monovalent cation and n is 1 when R ¹ is S ⁻ or N ⁻ R ¹² and 0 otherwise.

In the description of formula (1), the hydrocarbon group may be saturated or unsaturated, and may have a chain, branched, cyclic, or combination thereof. The number of carbon atoms is preferably 1 to 11, more preferably 1 to 8. Examples of heteroatoms include S, N, O, and the like. The heteroatom may be located between carbon atoms or at the end to which a hydrocarbon group is bonded. Further, the heteroatom may be present in a form substituting a hydrogen atom bonded to a carbon atom, or may be included in a group substituting a hydrogen atom bonded to a carbon atom. Specific examples of the group substituting a hydrogen atom containing a heteroatom include a hydroxyl group, a mercapto group, and an amino group.

In compound (1), R ¹ is S ⁻ , SR ¹¹ , N ⁻ R ¹² , NR ¹³ R ¹⁴ , or N=NR ¹⁵ . However, R ¹¹ to R ¹⁵ are as described above. In R ¹ , there are two types of atoms bonded to the carbon atom of S═C: S or N. That is, compound (1) can be roughly classified into two types depending on the type of R ¹ . Compound (1) in which the atom bonded to the carbon atom of S=C in R ¹ is S is hereinafter referred to as compound (1S). Compound (1) in which the atom bonded to the carbon atom of S=C in R ¹ is N is hereinafter referred to as compound (1N).

Compound (1) is a monovalent anion when R ¹ is S ^- or N ^- R ¹² , and has X ⁺ , which is a monovalent cation, as a counter cation. The type of X ⁺ is not particularly limited and is appropriately selected depending on the type of R ¹ or R ² .

In compound (1), R ² is a hydrocarbon group that may contain a heteroatom. The types of hydrocarbon groups and heteroatoms are as described above. The type of R ² is appropriately selected depending on the type of R ¹ . In any case of R ¹ , the atom bonded to the carbon atom of S═C in R ² is preferably a heteroatom. Preferred embodiments of compound (1S) and compound (1N) will be described below.

In compound (1S), when R ¹ is S ^- , the compound is referred to as compound (1Si), and when R ¹ is SR ¹¹ , it is referred to as compound (1Sii).

In the case of compound (1Si), examples of R ² include an alkyl group having 1 to 7 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 11 carbon atoms. The alkyl group that these hydrocarbon groups have may have a chain, branched, cyclic, or combination thereof. Further, these hydrocarbon groups may have a heteroatom between carbon atoms and/or as an atom bonded to a carbon atom of S═C. Further, an atom or a substituent substituting a hydrogen atom bonded to a carbon atom may have a heteroatom.

In compound (1Si), in R ² , the atom bonded to the carbon atom of S═C is preferably a heteroatom, and the heteroatom is preferably N or O. Specifically, R ² is NR ²³ R ²⁴ (R ²³ and R ²⁴ are each independently a hydrocarbon group that may contain a hydrogen atom or a hetero atom, or a group that combines with each other to form a heterocycle). ), N=NR ²⁵ (R ²⁵ is a hydrocarbon group), and OR ²⁶ (R ²⁶ is a hydrocarbon group which may contain a hetero atom).

R ²³ , R ²⁴ , R ²⁵ and R ²⁶ each independently include an alkyl group having 1 to 7 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 11 carbon atoms. In the case of an alkyl group, the number of carbon atoms is more preferably 1 to 3. In the case of an aryl group, the number of carbon atoms is more preferably 6 to 7. In the case of an aralkyl group, the number of carbon atoms is more preferably 7 to 8. Note that the alkylene group or alkyl group contained in the alkyl group, aryl group, or aralkyl group mentioned above may have a chain, branched, cyclic, or a combination of these structures.

Furthermore, the hydrocarbon group in R ²³ , R ²⁴ , and R ²⁶ may have a heteroatom as an atom bonded between carbon atoms and/or to a carbon atom in S═C. Further, an atom or a substituent substituting a hydrogen atom bonded to a carbon atom may have a heteroatom. When R ²³ and R ²⁴ are bonded to each other to form a ring, the number of members of the N-containing heterocycle is 3 to 7, preferably 5 to 6. Furthermore, the hydrogen atom bonded to the atom constituting the ring of the N-containing heterocycle is an alkyl group having 1 to 3 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 11 carbon atoms, or an OH group. may be replaced with .

Specifically, R ² in compound (1Si) is preferably NR ²³ R ²⁴ and OR ²⁶ . Specific examples of compound (1Si) are shown in Table 1. In Table 1, "Ph" represents a phenyl group. Note that a specific example of X ⁺ will be described later. Further, among the compounds (1Si) shown in Table 1, chemical formulas of preferred compounds are shown. Table 1 also shows chemical formula numbers.

In each of the above formulas, X ⁺ represents a monovalent cation.
Specific examples of X ⁺ in compound (1Si) include alkali metal ions such as Na ⁺ and K ⁺ , NH ₄ ⁺ , NH ₃ ⁺ R ⁵¹ , NH ₂ ⁺ R ⁵² R ⁵³ , NH ⁺ R ⁵⁴ R ⁵⁵ R ⁵⁶ , N ⁺ R ⁵⁷ R ⁵⁸ R ⁵⁹ R ⁶⁰ , and the like. R ⁵¹ , R ⁵² , R ⁵³ , R ⁵⁴ , R ⁵⁵ , R ⁵⁶ , R ⁵⁷ , R ⁵⁸ , R ⁵⁹ , and R ⁶⁰ each independently represent an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 6 to 18 carbon atoms; 12 aryl groups or aralkyl groups having 7 to 13 carbon atoms. In the case of an alkyl group, the number of carbon atoms is more preferably 1 to 4. In the case of an aryl group, the number of carbon atoms is more preferably 6 to 7. In the case of an aralkyl group, the number of carbon atoms is more preferably 7 to 8. Note that the alkylene group or alkyl group contained in the alkyl group, aryl group, or aralkyl group mentioned above may have a chain, branched, cyclic, or a combination of these structures.

Note that in NH ₂ ⁺ R ⁵² R ⁵³ , R ⁵² and R ⁵³ may be bonded to each other to form a ring. In NH ⁺ R ⁵⁴ R ⁵⁵ R ⁵⁶ , any two of R ⁵⁴ , R ⁵⁵ , and R ⁵⁶ may be bonded to each other to form a ring. In N ⁺ R ⁵⁷ R ⁵⁸ R ⁵⁹ R ⁶⁰ , any two of R ⁵⁷ , R ⁵⁸ , R ⁵⁹ , and R ⁶⁰ may be bonded to each other to form a ring. In this case, the number of members of the N-containing heterocycle is 3 to 7, preferably 5 to 6. Furthermore, the hydrogen atom bonded to the atom constituting the ring of the N-containing heterocycle is substituted with an alkyl group having 1 to 3 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 11 carbon atoms. You can leave it there.

Specific examples of NH ₂ ⁺ R ⁵² R ⁵³ include monovalent cations represented by the following formulas (X-1) to (X-4).

In compound (1Si), when R ² is NR ²³ R ²⁴ , X ⁺ is preferably Na ⁺ , K ⁺ , NH ₄ ⁺ , NH ₂ ⁺ R ⁵² R ⁵³ or the like. Furthermore, when X ⁺ is NH ₂ ⁺ R ⁵² R ⁵³ , R ²³ and R ²⁴ are preferably the same as R ⁵² and R ⁵³ . For example, X ⁺ in compound (1Si-2) is preferably a cation (X-1). Similarly, X ⁺ in compound (1Si-5) is the cation (X-3), X ⁺ in compound (1Si-6) is the cation (X-4), and X ⁺ in compound (1Si-7) is The cation (X-2) is preferable.

In compound (1Si), when R ² is OR ²⁶ , X ⁺ is preferably an alkali metal ion such as Na ⁺ or K ⁺ , and more preferably K ⁺ . In addition, compound (1Si) may be used as a hydrate if necessary. For example, when X ⁺ is Na ⁺ in compound (1Si-1), a dihydrate of the compound is known, and such a hydrate may be used in the present polishing composition. However, in that case, the content of compound (1) shown below is shown as the amount excluding H ₂ O of the hydrate.

In compound (1Sii), R ¹ is SR ¹¹ , and R ¹¹ is preferably a hydrocarbon group that may contain a hetero atom. Examples of R ¹¹ include SC(=S)-R ³ . Here, examples of R ³ include the same groups as R ² .

R ² in compound (1Sii) can be the same as R ² in compound (1Si) above, including preferred embodiments. Specific examples of the compound (1Sii) include the following compound (1Sii-1).

In compound (1N), when R ¹ is NR ¹³ R ¹⁴ , it is called compound (1Ni), when R ¹ is N=NR ¹⁵ , it is called compound (1Nii), and when R ¹ is N ^- R ¹² , it is called compound (1Niii). shall be.

R ¹³ and R ¹⁴ of NR ¹³ R ¹⁴ in compound (1Ni) are each independently a hydrocarbon group that may contain a hydrogen atom or a hetero atom, or a group that combines with each other to form a heterocycle. R ¹³ and R ¹⁴ are preferably both hydrogen atoms, more preferably one of them is a hydrogen atom, and the other is a hydrocarbon group containing a hetero atom. Examples of the hydrocarbon group which may contain a heteroatom include an alkyl group having 1 to 7 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 11 carbon atoms. In the case of an alkyl group, the number of carbon atoms is more preferably 1 to 3. In the case of an aryl group, the number of carbon atoms is more preferably 6 to 7. In the case of an aralkyl group, the number of carbon atoms is more preferably 7 to 8. Note that the alkylene group or alkyl group contained in the alkyl group, aryl group, or aralkyl group mentioned above may have a chain, branched, cyclic, or a combination of these structures.

Further, these hydrocarbon groups may have a heteroatom between carbon atoms and/or as an atom bonded to a nitrogen atom. A nitrogen atom is preferred as the heteroatom bonded to a nitrogen atom. When either R ¹³ or R ¹⁴ is a hydrocarbon group having a hetero atom, the group is preferably NR ³³ R ³⁴ . R ³³ and R ³⁴ are each independently a hydrocarbon group that may contain a hydrogen atom or a hetero atom, or a group that combines with each other to form a heterocycle.

In compound (1Ni), R ² includes a hydrocarbon group containing a carbon atom or a heteroatom. In R ² , the atom bonded to the carbon atom of S═C is preferably a carbon atom. Specifically, R ² includes CH ₃ , CH ₂ CH ₃ , C(=S)NH ₂ , C(=O)OCH ₂ CH ₃ , Ph, CH ₂ Ph, PhCl (ortho form, meta form, para form). ), PhCF ₃ (ortho form, meta form, para form), PhOH (ortho form, meta form, para form), 2-Py, 3-Py, and 4-Py. In addition, the said "Py" shows a pyridyl group. Further, specific examples of R ² include the same groups as R ² in the case of compound (1Si). In compound (1Ni), it is also preferable that the atom bonded to the carbon atom of S═C in R ² is a heteroatom, and the heteroatom is preferably a nitrogen atom. Specifically, R ² is NR ⁴³ R ⁴⁴ (R ⁴³ and R ⁴⁴ are each independently a hydrocarbon group that may contain a hydrogen atom or a hetero atom, or a group that combines with each other to form a heterocycle). ) or N=NR ⁴⁵ (R ⁴⁵ is a hydrocarbon group).

R ⁴³ , R ⁴⁴ and R ⁴⁵ each independently include an alkyl group having 1 to 7 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 11 carbon atoms. In the case of an alkyl group, the number of carbon atoms is more preferably 1 to 3. In the case of an aryl group, the number of carbon atoms is more preferably 6 to 7. In the case of an aralkyl group, the number of carbon atoms is more preferably 7 to 8. Note that the alkylene group or alkyl group contained in the alkyl group, aryl group, or aralkyl group mentioned above may have a chain, branched, cyclic, or a combination of these structures.

Further, the hydrocarbon group in R ⁴³ and R ⁴⁴ may have a hetero atom as an atom bonded between carbon atoms and/or to a carbon atom of S═C. When R ⁴³ and R ⁴⁴ are bonded to each other to form a ring, the number of members of the N-containing heterocycle is 3 to 7, preferably 5 to 6. Furthermore, the hydrogen atom bonded to the atom constituting the ring of the N-containing heterocycle is substituted with an alkyl group having 1 to 3 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 11 carbon atoms. You can leave it there.

R ¹⁵ in N=NR ¹⁵ in compound (1Nii) is a hydrocarbon group. Examples of the hydrocarbon group include an alkyl group having 1 to 7 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 11 carbon atoms. In the case of an alkyl group, the number of carbon atoms is more preferably 1 to 3. In the case of an aryl group, the number of carbon atoms is more preferably 6 to 7. In the case of an aralkyl group, the number of carbon atoms is more preferably 7 to 8. Note that the alkylene group or alkyl group contained in the alkyl group, aryl group, or aralkyl group mentioned above may have a chain, branched, cyclic, or a combination of these structures.

Examples of R ² in compound (1Nii) include the same groups as R ² in compound (1Ni), and preferred embodiments can also be made in the same manner.

R ¹² of N ^- R ¹² in compound (1Niii) is a hydrogen atom or a hydrocarbon group which may contain a hetero atom. Examples of R ¹² include the same embodiments as R ¹³ and R ¹⁴ . Examples of X ⁺ in compound (1Niii) include the same embodiments as X ⁺ in compound (1Si). Further, R ² in compound (1Niii) can be the same as R ² in the above compound (1Ni), including preferred embodiments.

Specific examples of compound (1Ni) and compound (1Nii) are shown in Table 2. In Table 2, "Ph" represents a phenyl group. Further, chemical formulas are shown for preferred compounds among the compound (1Ni) and compound (1Nii) shown in Table 2. Table 2 also shows the chemical formula numbers.

Among these compounds (1), compounds (1Si-1) to (1Si-7), compounds (1Sii-21) to (1Sii-25), compounds (1Ni-1), (1Ni-2), and compounds ( 1Nii-1) (1Nii-2) are preferred, and (1Si-1), (1Si-2), (1Si-4), (1Si-5), and (1Si-6) are more preferred. The present polishing composition may contain only one type of compound (1), or may contain two or more types of compound (1).

The content of compound (1) in the present polishing composition is preferably 0.0001% by mass or more and 10% by mass or less, more preferably 0.005% by mass or more and 5% by mass or less based on the total mass of the polishing composition. Preferably, 0.01% by mass or more and 1% by mass or less is more preferable. The content of compound (1) in the present polishing composition is preferably from 3×10 ⁻⁷ mol/kg to 7×10 ⁻² mol/kg, and 2×10 ⁻⁵ mol/kg to the polishing composition. The amount is more preferably 4×10 ⁻² mol/kg or more, and even more preferably 4×10 ⁻⁵ mol/kg or more and 7×10 ⁻³ mol/kg or less.

By setting the content of compound (1) to 0.0001% by mass or more, the present polishing composition can polish a metal layer, particularly a metal layer made of metal M, at a high polishing rate. By controlling the content of compound (1) to 10% by mass or less, it is possible to prevent corrosion of the metal layer and prevent aggregation of abrasive grains. By setting the content of compound (1) to 3 x 10 ^-7 mol/kg or more, the present polishing composition can polish a metal layer, particularly a metal layer made of metal M, at a high polishing rate. . By controlling the content of compound (1) to 7×10 ⁻² mol/kg or less, it is possible to prevent corrosion of the metal layer and agglomeration of abrasive grains.

<Abrasive>
This polishing composition contains cerium oxide particles as an abrasive grain as an essential component. Since this polishing composition contains cerium oxide particles, it can polish a metal layer, particularly a metal layer made of metal M, at a high polishing rate. Further, when a metal layer and an insulating film made of silicon oxide or the like coexist on the surface to be polished and the mixed films are planarized at the same time, the polishing rate of the insulating film etc. can be adjusted.

The present polishing composition may contain other known abrasive grains in addition to cerium oxide (ceria). Abrasive grains that can be contained here include silicon oxide (silica), aluminum oxide (alumina), zirconium oxide (zirconia), titanium oxide (titania), chromium oxide, iron oxide, tin oxide, zinc oxide, germanium oxide, and manganese oxide. Examples include fine particles made of metal oxides such as diamond, silicon carbide, boron carbide, boron nitride, and the like.

The cerium oxide particles contained in the present polishing composition are not particularly limited as long as they can be used as abrasive grains, but for example, the method described in JP-A-11-12561 and JP-A-2001-35818 can be used. Cerium oxide particles manufactured by can be used. That is, a cerium hydroxide gel is created by adding an alkali to an aqueous cerium (IV) ammonium nitrate solution, and then cerium oxide particles are obtained by filtering, washing, and firing, or high-purity cerium carbonate is crushed and fired, and then Cerium oxide particles obtained by pulverization and classification can be used. Furthermore, as described in Japanese Patent Publication No. 2010-505735, cerium oxide particles obtained by chemically oxidizing cerium (III) salt in a liquid can also be used.

The particle size of the abrasive grains is preferably 10 nm or more and 200 nm or less in terms of average secondary particle size. Since the abrasive grains exist in the polishing composition as agglomerated particles (secondary particles) in which primary particles are aggregated, the preferred particle size of the abrasive grains is expressed by the average secondary particle size. If the average secondary particle diameter exceeds 200 nm, the abrasive grain diameter is too large and it becomes difficult to increase the concentration of abrasive grains, and if the average secondary particle diameter is less than 10 nm, it becomes difficult to improve the polishing rate. The average secondary particle diameter of the abrasive grains is preferably in the range of 20 nm or more and 120 nm or less. The average secondary particle diameter is measured using a particle size distribution analyzer such as a laser diffraction/scattering type using a dispersion liquid dispersed in a dispersion medium such as pure water.

As the abrasive grains, cerium oxide particles may be used alone, or two or more types of other abrasive grains may be used in combination. In addition, when using cerium oxide particles and other abrasive grains together, it is preferable that the abrasive grains contain cerium oxide particles in an amount of 0.5% by mass or more, more preferably 20% by mass or more, and 100% by mass. It is particularly preferable that there be.

When using abrasive grains, the ratio of the abrasive grains to the total mass of the polishing composition is preferably 0.005% by mass or more and 10% by mass or less, more preferably 0.01% by mass or more and 5% by mass or less, and 0.005% by mass or more and 10% by mass or less, more preferably 0.01% by mass or more and 5% by mass or less. It is more preferably 0.05% by mass or more and 2% by mass or less, even more preferably 0.05% by mass or more and 1% by mass or less, and particularly preferably 0.05% by mass or more and 0.6% by mass or less.

As the abrasive grains, an abrasive dispersion liquid in which the abrasive grains are dispersed in a medium in advance may be used. Water can be preferably used as the medium.

<Water>
This polishing composition contains water as an essential component. This polishing composition is typically made by dissolving compound (1) in a liquid medium containing water. The liquid medium in this polishing composition mainly consists of water, and it is preferable that the liquid medium consists of only water or a mixture of water and a water-soluble solvent. As the water, it is preferable to use pure water that has been subjected to ion exchange to remove foreign substances. As the water-soluble solvent, water-soluble alcohol, water-soluble polyol, water-soluble ester, water-soluble ether, etc. can be used.

The liquid medium in the present polishing composition is preferably water alone or a mixed solvent of water and a water-soluble organic solvent containing 80% by mass or more, and most preferably consists essentially of water only. Further, the proportion of the liquid medium in the present polishing composition is preferably 85% by mass or more, more preferably 90% by mass or more, particularly preferably 95% by mass or more. It is preferable that substantially the entire amount of this liquid medium consists of water, and in that case, the content of water in the present polishing composition is preferably 90% by mass or more, particularly preferably 95% by mass or more.

In addition, the ratio of each component of this polishing composition refers to the composition ratio when polishing is performed. When the concentrated polishing composition is diluted prior to polishing and the diluted product is used for polishing, the proportions of each component described above and below are the proportions in this diluted product. Concentrated polishing compositions are usually diluted with a liquid medium (particularly water), in which case the relative proportions of each component, excluding the liquid medium, usually do not change before and after dilution.

(pH)
The pH of the present polishing composition is preferably 2.0 or more and 11.0 or less. If the pH is in the range of 2.0 or more and 11.0 or less, the present polishing composition can polish a metal layer, especially a metal layer made of metal M, at a high polishing rate, and has good storage stability. Also excellent. Further, the polishing composition can be handled more safely when transporting or using the polishing composition. The pH of the present polishing composition is more preferably 3.0 or more and 10.0 or less, particularly preferably 4.0 or more and 9.5 or less, and extremely preferably 4.5 or more and 9.5 or less.

This polishing composition contains various inorganic acids, organic acids, salts thereof, or basic compounds as pH adjusters to adjust the pH to a predetermined value of 2.0 or more and 11.0 or less. It's okay.

The inorganic acid or inorganic acid salt is not particularly limited, but for example, nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, ammonium salts or potassium salts thereof, etc. can be used. The organic acid or other organic acid salt is not particularly limited, and for example, carboxylic acids such as formic acid, acetic acid, oxalic acid, malic acid, and citric acid, and their salts can be used.

The basic compound is preferably water-soluble, but is not particularly limited. Basic compounds include metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide, ammonia, tetramethylammonium hydroxide (hereinafter referred to as TMAH), and tetraethylammonium hydroxide. Quaternary ammonium hydroxides such as carbon dioxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; organic amines such as diethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, and ethylenediamine; and the like.

<Rust inhibitor>
The present polishing composition can contain a rust preventive agent as an optional component. As the rust preventive agent, a known rust preventive agent can be used, and examples thereof include nitrogen-containing heterocyclic compounds, nonionic surfactants, and the like.

Examples of nitrogen-containing heterocyclic compounds include pyrrole compounds, pyrazole compounds, imidazole compounds, triazole compounds, tetrazole compounds, pyridine compounds, pyrazine compounds, pyridazine compounds, pyridine compounds, indolizine compounds, indole compounds, isoindole compounds, Indazole compounds, purine compounds, quinolidine compounds, quinoline compounds, isoquinoline compounds, naphthyridine compounds, phthalazine compounds, quinoxaline compounds, quinazoline compounds, cinnoline compounds, buteridine compounds, thiazole compounds, isothiazole compounds, oxazole compounds, isoxazole compounds, furazane compounds, etc. can be mentioned.

Among these compounds, tetrazole compounds, pyrazole compounds, and triazole compounds, particularly triazole compounds, are preferred from the viewpoint of improving the surface flatness of the object to be polished.

Among the triazole compounds, a benzotriazole group having an amino group substituted with at least one hydroxyalkyl group is preferred in order to achieve the desired effect of the present invention. Here, the number of hydroxyalkyl groups is also not particularly limited, but from the viewpoint of dispersion stability in the polishing composition, it is preferably one or two.

The number of carbon atoms in the alkyl group in the hydroxyalkyl group is also not particularly limited, but from the viewpoint of suppressing a reduction in the polishing rate of the object to be polished, the number of carbon atoms is preferably 1 to 5, more preferably 1 to 4. , more preferably 2 to 3. In addition, when the number of hydroxyalkyl groups is two or more, the number of alkyl groups may be the same or different, but from the viewpoint of storage stability as a compound and prevention of oxidation of the compound. It is preferable that they are the same from the viewpoint of.

The triazole compound preferably has a condensed ring, and for example, one condensed with a benzene ring, naphthalene ring, anthracene ring, etc. is preferable from the viewpoint of stability as a compound and for preventing oxidation of the polishing composition. From this point of view, it is preferable that they are the same. Further, the triazole compound may have a substituent such as an alkyl group having 1 to 3 carbon atoms, a hydroxy group, or a halogen atom.

Examples of triazole compounds include, for example, 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, 1,2,3-triazole, 1,2,4-triazole , 1-methyl-1,2,4-triazole, methyl-1H-1,2,4-triazole-3-carboxylate, 1,2,4-triazole-3-carboxylic acid, 1,2,4-triazole Methyl -3-carboxylate, 1H-1,2,4-triazole-3-thiol, 3,5-diamino-1H-1,2,4-triazole, 3-amino-1,2,4-triazole-5 -thiol, 3-amino-1H-1,2,4-triazole, 3-amino-5-benzyl-4H-1,2,4-triazole, 3-amino-5-methyl-4H-1,2,4 -triazole, 3-nitro-1,2,4-triazole, 3-bromo-5-nitro-1,2,4-triazole, 4-(1,2,4-triazol-1-yl)phenol, 4- Amino-1,2,4-triazole, 4-amino-3,5-dipropyl-4H-1,2,4-triazole, 4-amino-3,5-dimethyl-4H-1,2,4-triazole, 4-amino-3,5-dipeptyl-4H-1,2,4-triazole, 5-methyl-1,2,4-triazole-3,4-diamine, 1H-benzotriazole, 1-hydroxybenzotriazole, 1 -Aminobenzotriazole, 1-carboxybenzotriazole, 5-chloro-1H-benzotriazole, 5-nitro-1H-benzotriazole, 5-carboxy-1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6 -dimethyl-1H-benzotriazole, 1-(1',2'-dicarboxyethyl)benzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]benzotriazole, 1-[N,N-bis Preferred are (hydroxyethyl)aminomethyl]-5-methylbenzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]-4-methylbenzotriazole, and the like.

Among these compounds, 2,2'-[[ (Methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, 1,2,3-triazole, 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5,6-dimethyl-1H-benzo Triazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]-5-methylbenzotriazole, 1-[N,N-bis(hydroxyethyl)aminomethyl]-4-methylbenzotriazole, 1,2, 3-triazole, 1,2,4-triazole, and the like are preferred.

Examples of pyrazole compounds include 1H-pyrazole, 4-nitro-3-pyrazolecarboxylic acid, 3,5-pyrazolecarboxylic acid, 3-amino-5-phenylpyrazole, 5-amino-3-phenylpyrazole. , 1-allyl-3,5-dimethylpyrazole, 3,4,5-tribromopyrazole, 3-aminopyrazole, 3,5-dimethylpyrazole, 3,5-di(2-pyridyl)pyrazole, 3,5- Diisopropylpyrazole, 3,5-dimethyl-1-hydroxymethylpyrazole, 3,5-dimethyl-1-phenylpyrazole, 3-methylpyrazole, 1-methylpyrazole, 4-methylpyrazole, N-methylpyrazole, 3-amino- 5-methylpyrazole, 3-amino-5-hydroxypyrazole, 4-amino-pyrazolo[3,4-d]pyrimidine, allopurinol, 4-chloro-1H-pyrazolo[3,4-D]pyrimidine, 3,4- Examples include dihydroxy-6-methylpyrazolo(3,4-B)-pyridine, 6-methyl-1H-pyrazolo[3,4-b]pyridin-3-amine, and the like.

Examples of imidazole compounds include imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, benzimidazole, 5,6-dimethylbenzimidazole, 2-aminobenzimidazole, 2-chlorobenzimidazole, 2-methylbenzimidazole, 2-(1-hydroxyethyl)benzimidazole, 2-hydroxybenzimidazole, 2-phenylbenzimidazole, 2 , 5-dimethylbenzimidazole, 5-methylbenzimidazole, 5-nitrobenzimidazole, 1H-purine, 1,1'-carbonylbis-1H-imidazole, 1,1'-oxalyldiimidazole, 1,2,4, 5-tetramethylimidazole, 1,2-dimethyl-5-nitroimidazole, 1-(3-aminopropyl)imidazole, 1-butylimidazole, 1-ethylimidazole, 1H-1,2,3-triazolo[4,5 -b] pyridine and the like.

Examples of tetrazole compounds include 1H-tetrazole, 5-methyltetrazole, 5-aminotetrazole, 5-amino-1-hydroxytetrazole, 1,5-pentamethylenetetrazole, 1-(2-dimethylaminoethyl)- Examples include 5-mercaptotetrazole and 5-phenyltetrazole.

Examples of indazole compounds include, for example, 1H-indazole, 5-amino-1H-indazole, 5-nitro-1H-indazole, 5-hydroxy-1H-indazole, 6-amino-1H-indazole, 6-nitro-1H -indazole, 6-hydroxy-1H-indazole, 3-carboxy-5-methyl-1H-indazole, and the like.

Examples of indole compounds include 1H-indole, 1-methyl-1H-indole, 2-methyl-1H-indole, 3-methyl-1H-indole, 4-methyl-1H-indole, 5-methyl-1H-indole, Indole, 6-methyl-1H-indole, 7-methyl-1H-indole, 4-amino-1H-indole, 5-amino-1H-indole, 6-amino-1H-indole, 7-amino-1H-indole, 4-hydroxy-1H-indole, 5-hydroxy-1H-indole, 6-hydroxy-1H-indole, 7-hydroxy-1H-indole, 4-methoxy-1H-indole, 5-methoxy-1H-indole, 6- Methoxy-1H-indole, 7-methoxy-1H-indole, 4-chloro-1H-indole, 5-chloro-1H-indole, 6-chloro-1H-indole, 7-chloro-1H-indole, 4-carboxy- 1H-indole, 5-carboxy-1H-indole, 6-carboxy-1H-indole, 7-carboxy-1H-indole, 4-nitro-1H-indole, 5-nitro-1H-indole, 6-nitro-1H- Indole, 7-nitro-1H-indole, 4-nitrile-1H-indole, 5-nitrile-1H-indole, 6-nitrile-1H-indole, 7-nitrile-1H-indole, 2,5-dimethyl-1H- Indole, 1,2-dimethyl-1H-indole, 1,3-dimethyl-1H-indole, 2,3-dimethyl-1H-indole, 5-amino-2,3-dimethyl-1H-indole, 7-ethyl- 1H-indole, 5-(aminomethyl)indole, 2-methyl-5-amino-1H-indole, 3-hydroxymethyl-1H-indole, 6-isopropyl-1H-indole, 5-chloro-2-methyl-1H - Examples include indole.

Examples of thiazoles include 2,4-dimethylthiazole and the like. Examples of benzothiazoles include 2-mercaptobenzothiazole and the like.

Examples of nonionic surfactants include derivatives of higher alcohols in which the lipophilic group (the group represented by R in the following examples) has 12 to 18 carbon atoms. Examples include glycerin fatty acid ester (RCOOCH ₂ CH (OH) CH ₂ OH), sorbitan fatty acid ester, sucrose fatty acid ester, and esters with naturally occurring fatty acids. Also, fatty alcohol ethoxylates (RO(CH ₂ CH ₂ O) _n H), polyoxyethylene alkylphenyl ethers (RC ₆ H ₄ O(CH ₂ CH ₂ O) _n H), alkyl glycosides (RC ₆ H ₁₁ O Examples include ethers such as ₆ ).

The present polishing composition can contain one or more rust preventives. The content of the rust preventive agent in the present polishing composition is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.005% by mass or more and 1% by mass or less, based on the total amount of the polishing composition. More preferably 0.01% by mass or more and 0.5% by mass or less.

<Dispersant>
In addition to the above-mentioned components, the present polishing composition may contain a dispersant (or anti-agglomeration agent) as an optional component. A dispersant is something that is contained in order to stably disperse abrasive grains in a dispersion medium such as pure water. As the dispersant, known dispersants can be used, such as anionic, cationic, and amphoteric surfactants, and anionic, cationic, and amphoteric polymer compounds; A species or two or more species can be included.

As the dispersant, a polymer compound having a carboxy group, a sulfo group, a phosphonic acid group, a carboxylic acid group, a sulfonic acid group, or a phosphonic acid group is preferable, and specifically, acrylic acid, methacrylic acid, maleic acid, p- A homopolymer of a monomer having a carboxy group, a sulfo group, or a phosphonic acid group such as styrene sulfonic acid or vinylphosphonic acid, or a portion of the carboxy group, sulfo group, or phosphonic acid group of the polymer becomes a salt such as an ammonium salt. Examples include homopolymers that are In addition, a monomer having a carboxy group, a sulfo group, or a phosphonic acid group and a monomer having a carboxylic acid group, a sulfonic acid group, or a phosphonic acid group, and a monomer having a carboxylic acid group, a sulfonic acid group, or a phosphonic acid group and a carboxylic acid group Copolymers with derivatives such as alkyl esters are also preferably used. Furthermore, polymer compounds such as polyvinyl alcohol, anionic surfactants such as ammonium oleate, ammonium lauryl sulfate, and triethanolamine lauryl sulfate can be suitably used.

Among these, polymers having a carboxy group or a salt thereof are particularly preferred as the dispersant. Specifically, polyacrylic acid or a polymer in which at least a portion of the carboxyl groups of polyacrylic acid is substituted with an ammonium carboxylate group (hereinafter referred to as ammonium polyacrylate) can be mentioned. When using a polymer compound such as ammonium polyacrylate, its weight average molecular weight is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, particularly preferably 3,000 to 25,000.

The content of the dispersant in the present polishing composition is preferably 0.001 to 0.5% by mass based on the total mass of the polishing composition, particularly for the purpose of maintaining dispersion stability. It is preferably 0.001 to 0.2% by mass.

Further, the present polishing composition may contain a lubricant, a viscosity imparting agent or a viscosity modifier, a preservative, and the like as appropriate.

Although an oxidizing agent may be added to the present polishing composition, it is preferable that the metal layer can be polished at a high polishing rate without using an oxidizing agent, and that the polishing composition does not substantially contain an oxidizing agent. The oxidizing agent typically includes a peroxide having an oxygen-oxygen bond that is dissociated by external energy such as heat or light to generate radicals. Examples of peroxide-based oxidizing agents include hydrogen peroxide, persulfates, periodic acid, periodates such as potassium periodate, and inorganic peroxides such as peroxocarbonates, peroxosulfates, and peroxolinates. Examples include oxides and organic peroxides such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, performic acid, peracetic acid, and metachloroperbenzoic acid. Examples of persulfates include ammonium persulfate and potassium persulfate. Other examples include iodate, bromate, persulfate, cerium nitrate, hypochlorous acid, and ozone water.

In conventional polishing compositions for forming wiring, a high polishing rate can be achieved in polishing a metal layer by containing an oxidizing agent, but there are problems with the disadvantages such as corrosion of metal wiring and corrosion of polishing equipment. Since the present polishing composition does not contain an oxidizing agent, it is possible to polish a metal layer at a high polishing rate without causing corrosion of metal wiring or polishing equipment caused by such an oxidizing agent.

<Method for preparing polishing composition>
To prepare this polishing composition, compound (1), which is an essential component, and cerium oxide particles are added to a water-containing liquid medium such as pure water or ion-exchanged water, and optional components are added as necessary. All you have to do is add a rust preventive agent, etc., and mix. At that time, a pH adjuster may be added as necessary to adjust the pH of the resulting polishing composition to be within the above-mentioned preferred range. In order to incorporate cerium oxide and other abrasive grains into the present polishing composition, a method is used in which the above-mentioned components are added to a dispersion liquid in which abrasive grains are dispersed and mixed. After mixing, a uniform polishing composition can be obtained by stirring for a predetermined period of time using a stirrer or the like. Further, after mixing, a better dispersion state can be obtained using an ultrasonic disperser.

The present polishing composition does not necessarily need to be supplied to the polishing site as a mixture of all constituent components in advance. When the polishing composition is supplied to the polishing site, the components may be mixed to form the composition and pH of the polishing composition.

<Polishing method>
The present invention provides a polishing method for polishing a surface to be polished of a semiconductor integrated circuit device using the polishing composition of the present invention. The polishing method of the present invention is a method of supplying the present polishing composition to a polishing pad, bringing the surface to be polished of a semiconductor integrated circuit device into contact with the polishing pad, and polishing by relative movement between the two, The surface to be polished includes a metal containing at least one selected from cobalt, ruthenium, and molybdenum, that is, metal M.

In the present invention, the term "surface to be polished" refers to an intermediate surface that appears during the process of manufacturing a semiconductor integrated circuit device. For example, in polishing the semiconductor integrated circuit device shown in FIGS. 1 and 2, a metal layer, a polishing stop layer, and an insulating layer can be the objects to be polished. In this case, a metal layer is present on the "surface to be polished," and in addition to the metal layer, a polishing stop layer and an insulating layer may also be present.

Furthermore, the term "metal layer" in the present invention means a layer consisting of a planar metal layer, but it does not necessarily mean a layer that is spread over one surface as shown in FIG. A layer as a collection of wiring is also included. Furthermore, it can be considered a "metal layer" including parts such as vias for electrically connecting the planar metal layer to other parts.

The polishing shown in FIGS. 1 and 2 includes a first polishing step in which only the metal layer 4 made of metal M is polished, and a second polishing step in which the metal layer 4, the polishing stop layer 3, and the insulating layer 2 are polished. It has a step polishing process. The polishing composition according to the present invention may be used at any stage of this polishing process. In the first polishing step using this polishing composition, the metal layer 4 can be polished at high speed. In the second polishing step using the present polishing composition, the metal layer 4, the polishing stop layer 3, and the insulating layer 2 are polished substantially uniformly at a high polishing rate, and the surface to be polished can be efficiently planarized.

Note that a silicon oxide (SiO ₂ ) film is known as the insulating layer 2. Such a silicon oxide film is generally made by depositing tetraethoxysilane (TEOS) by the CVD method.

Furthermore, in recent years, low dielectric constant insulating layers have been increasingly used instead of this SiO ₂ film for the purpose of suppressing signal delay. In addition to low dielectric constant materials such as films made of fluorine-added silicon oxide (SiOF), organic SOG (films containing organic components obtained by spin-on-glass), and porous silica, this material can also be made using the CVD method (chemical vapor phase method). A SiOC film is known.

Examples of low dielectric organic silicon materials include: Black Diamond (relative permittivity 2.7, technology from Applied Materials), Coral (relative permittivity 2.7, technology from Novellus Systems), and Aurora2.7. (relative dielectric constant 2.7, technology from Japan ASM Co., Ltd.), among others, compounds having a Si--CH ₃ bond are preferably used. This polishing composition can be suitably used when these various insulating layers are employed.

Further, as the polishing stop layer 3, a SiN layer, a TiN layer, etc. are known. This polishing composition can be suitably used when employing these various polishing stop layers. Since the present polishing composition does not contain an oxidizing agent, it is unlikely to modify SiN or the like by oxidation, weakening its function as a polishing stopper layer, and making it difficult to control polishing.

In the above polishing method, a conventionally known polishing device can be used as the polishing device. FIG. 3 is a diagram showing an example of a polishing apparatus that can be used in the embodiment of the present invention. This polishing apparatus 20 includes a polishing head 22 that holds a semiconductor integrated circuit device 21, a polishing surface plate 23, a polishing pad 24 attached to the surface of the polishing surface plate 23, and a polishing composition 25 applied to the polishing pad 24. A supply pipe 26 for supplying. While supplying the polishing composition 25 from the supply pipe 26, the surface to be polished of the semiconductor integrated circuit device 21 held by the polishing head 22 is brought into contact with the polishing pad 24, and the polishing head 22 and the polishing surface plate 23 are moved relative to each other. It is configured to rotate and perform polishing. Note that the polishing apparatus used in the embodiments of the present invention is not limited to such a structure.

The polishing head 22 may perform not only rotational movement but also linear movement. Furthermore, the polishing surface plate 23 and the polishing pad 24 may be of the same size as the semiconductor integrated circuit device 21 or smaller. In that case, it is preferable to relatively move the polishing head 22 and polishing platen 23 so that the entire surface of the semiconductor integrated circuit device 21 to be polished can be polished. Furthermore, the polishing surface plate 23 and the polishing pad 24 do not need to be rotatable, and may be belt-type, for example, that move in one direction.

There are no particular restrictions on the polishing conditions of the polishing device 20, but by applying a load to the polishing head 22 and pressing it against the polishing pad 24, it is possible to further increase the polishing pressure and improve the polishing speed. The polishing pressure is preferably about 0.5 to 50 kPa, and more preferably about 3 to 40 kPa from the viewpoint of uniformity of the polishing rate within the polished surface of the semiconductor integrated circuit device 21, flatness, and prevention of polishing defects such as scratches. The rotation speed of the polishing surface plate 23 and polishing head 22 is preferably about 50 to 500 rpm, but is not limited thereto. The supply amount of the polishing composition 25 is appropriately adjusted and selected depending on the constituent materials of the surface to be polished, the composition of the polishing composition, the polishing conditions described above, etc. For example, when polishing a wafer with a diameter of 200 mm, For this purpose, a feed rate of about 100 to 300 ml/min is preferable.

As the polishing pad 24, one made of general non-woven fabric, foamed rigid polyurethane, porous resin, non-porous resin, etc. can be used. In addition, in order to promote the supply of the polishing composition 25 to the polishing pad 24 or to allow a certain amount of the polishing composition 25 to accumulate on the polishing pad 24, the surface of the polishing pad 24 may have a lattice pattern, concentric circles, etc. A spiral groove or the like may be formed.

Further, if necessary, polishing may be performed while conditioning the surface of the polishing pad 24 by bringing a pad conditioner into contact with the surface of the polishing pad 24.

EXAMPLES The present invention will be specifically explained below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1 to 11 are examples, and Examples 12 to 13 are comparative examples. In the following examples, "%" means mass % unless otherwise specified. Further, the characteristic values were measured and evaluated by the following method.

[pH]
The pH was measured using a pH meter HM-30R manufactured by DKK Toa.

[Average secondary particle diameter]
The average secondary particle diameter was measured using a laser scattering/diffraction type particle size distribution measuring device (manufactured by Horiba, Ltd., device name: LA-920).

[Polishing properties]
The polishing properties were evaluated by performing the following polishing using a fully automatic CMP polishing device (manufactured by Applied Materials, device name: Mirra). A foamed hard polyurethane pad was used as the polishing pad, and a CVD diamond pad conditioner (manufactured by 3M, trade name: Trizact B5) was used to condition the polishing pad. The polishing conditions were as follows: the polishing pressure was 13.8 kPa (2 psi), the rotation speed of the polishing surface plate was 80 rpm, and the rotation speed of the polishing head was 79 rpm. Further, the supply rate of the abrasive was 200 ml/min.

In order to measure the polishing rate [Angstrom/min], the following (A) and (B) were prepared as objects to be polished (objects to be polished).
(A) A silicon dioxide film-coated substrate in which a silicon dioxide film was formed on an 8-inch silicon wafer by plasma CVD using tetraethoxysilane as a raw material.
(B) A ruthenium layered substrate having a ruthenium layer on an 8-inch silicon wafer.

A film thickness meter UV-1280SE manufactured by KLA-Tencor was used to measure the thickness of the silicon dioxide film formed on the substrate. Further, a resistivity measuring device VR300D manufactured by Kokusai Electric Semiconductor Service Co., Ltd. was used to measure the thickness of the ruthenium layer.

[Example 1]
Pure water, compound (1Si-1)/K ⁺ , polyacrylic acid, and a pH adjuster are mixed to prepare a mixed solution adjusted to a predetermined pH, and this mixed solution is further mixed with an average primary particle size. Cerium oxide particles of 60 nm (average secondary particle size 90 nm) were added to a cerium oxide dispersion liquid in pure water and mixed to obtain a polishing composition (1) having a pH of 9.0. The content of each component in the polishing composition (1) is as shown in Table 3.

[Examples 2 to 4]
Polishing compositions (2) to (4) were obtained in the same manner as in Example 1 except that the content of cerium oxide particles in Example 1 was changed. The polishing properties of polishing compositions (1) to (4) were measured by the method described above. The results are also shown in Table 3.

Compound (1Si-1)·K ⁺ is a compound in which X ⁺ is K ⁺ in compound (1Si-1). Hereinafter, compound (1) will be expressed as a combination of the abbreviation of the compound in Table 1 and the cation itself representing X ⁺ or its abbreviation, similar to compound (1Si-1).K ⁺ .

[Examples 5 to 11]
In the same manner as in Example 2, except that compound (1) shown in Table 3 was used instead of compound (1Si-1) K ⁺ , and the amount of cerium oxide and pH were adjusted to the values shown in Table 3. Polishing compositions (5) to (11) of Examples 5 to 11 were prepared, and their polishing properties were measured by the method described above. The results are shown in Table 3.

[Example 12]
Compound (1Si-1)·K ⁺ and water were mixed, and the pH was further adjusted to 10.0 with a pH adjuster to obtain a polishing composition (12). The content of each component in the polishing composition (12) is as shown in Table 3. The polishing properties of the polishing composition (12) were measured by the method described above. The results are also shown in Table 3.

[Example 13]
As Example 13, a polishing composition (13) was prepared in the same manner as in Example 3 except that the content of cerium oxide particles was adjusted to the values shown in Table 3 and compound (1) was not contained, and the polishing composition (13) was prepared by the above method. The polishing properties were measured. Table 3 shows the composition and evaluation results of polishing composition (13).

From Table 3, it can be said that the polishing compositions of Examples have a high polishing rate for the ruthenium layer. By changing the type of compound represented by formula (1), it is possible to change the polishing rate of the ruthenium layer. Further, by adjusting the concentration of the cerium oxide abrasive grains, it is also possible to arbitrarily adjust the polishing rate of the silicon dioxide film and the selection ratio of the polishing rates of the ruthenium layer and the silicon dioxide film.

According to the polishing composition and polishing method of the present invention, wiring of a semiconductor integrated circuit device using metals such as cobalt, ruthenium, molybdenum, etc., which have low resistance and can be made into thin wires, and in particular, using these metals as embedded wirings. In the composition used for CMP for forming the metal layer, it is possible to polish the metal layer at a high polishing rate without using an oxidizing agent. Furthermore, at the same time, an insulating film such as a silicon dioxide film can also be polished at an arbitrary polishing rate. As described above, in the step of polishing the metal layer and the insulating layer, it becomes possible to polish the metal layer and the insulating layer evenly, and it becomes possible to perform polishing while ensuring the flatness of the surface to be polished.

DESCRIPTION OF SYMBOLS 1... Semiconductor substrate, 2... Insulating film, 3... Polishing stop layer, 4... Metal layer, 6... Embedded wiring,
20... Polishing device, 21... Semiconductor integrated circuit device, 22... Polishing head, 23... Polishing surface plate,
24... Polishing pad, 25... Polishing composition, 26... Supply piping

Claims (10)

A polishing composition comprising a compound represented by the following formula (1), cerium oxide particles, and water.

Formula (1)
In formula (1), R ¹ is S ⁻ or N R ¹³ R ¹⁴ (R ¹³ and R ¹⁴ are each independently a hydrocarbon group that may contain a hydrogen atom or a hetero atom. ) ,
In the case where R ¹ is S ^- , R ² is NR ²³ R ²⁴ (R ²³ and R ²⁴ are a group that combines with each other to form a heterocycle), or OR ²⁶ (R ²⁶ is a hetero is a hydrocarbon group that may contain atoms),
In the case where R ¹ is N ^- R ¹³ R ¹⁴ , R ² is a hydrocarbon group or NR ⁴³ R ⁴⁴ (R ⁴³ and R ⁴⁴ are each independently a hydrogen atom or a hydrocarbon group. ) and
X ⁺ is a monovalent cation ,
n is 1 . A polishing composition comprising a compound represented by the following formula (2), cerium oxide particles, and water.

Formula (2)
In formula (2), R ¹ Ha, N ^- R ¹² (R ¹² is a hydrocarbon group which may contain a hydrogen atom or a heteroatom. ), N.R. ¹³ R ¹⁴ (R ¹³ and R ¹⁴ are hydrocarbon groups that may each independently contain a hydrogen atom or a heteroatom, or groups that combine with each other to form a heterocycle. ), or N=NR ¹⁵ (R ¹⁵ is a hydrocarbon group. ) and
R ² is, NR ⁴³ R ⁴⁴ (R ⁴³ and R ⁴⁴ are hydrocarbon groups that may each independently contain a hydrogen atom or a heteroatom, or groups that combine with each other to form a heterocycle. ) or N=NR ⁴⁵ (R ⁴⁵ is a hydrocarbon group. ) and
X ⁺ is a monovalent cation,
n is R ¹ is N ^- R ¹² It is 1 if , and 0 otherwise. The polishing composition according to any one of claims 1 to 2 , which contains substantially no oxidizing agent. The polishing composition according to any one of claims 1 to 3 , further comprising a dispersant. The polishing composition according to claim 4 , wherein the dispersant is a polymer compound having a carboxy group or a carboxylic acid group. The polishing composition according to any one of claims 1 to 5 , which has a pH of 2.0 or more and 11.0 or less. The polishing composition according to any one of claims 1 to 5 , which has a pH of 4.0 or more and 9.5 or less. The polishing composition according to any one of claims 1 to 7 , wherein the content of the compound is 0.0001% by mass or more and 10% by mass or less based on the total mass of the polishing composition. The polishing composition according to any one of claims 1 to 8 is supplied to a polishing pad, the surface to be polished of a semiconductor integrated circuit device is brought into contact with the polishing pad, and polishing is performed by relative movement between the two. A polishing method, wherein the surface to be polished includes a metal containing at least one selected from cobalt, ruthenium, and molybdenum. A polishing method for manufacturing a semiconductor integrated circuit device having a pattern in which buried metal interconnections containing at least one selected from cobalt, ruthenium, and molybdenum and insulating layers are alternately arranged, the insulating layer having grooves. The polishing method according to claim 9 , wherein a metal layer made of the metal provided on the layer so as to fill the groove is polished using the polishing composition.

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