KR20080020946A - Metal polishing method - Google Patents

Abstract

A metal polishing method is provided to produce a shallow concave surface on a wafer by using polishing liquid containing heterocyclic ring compound, organic acid containing second grade or third grade nitrogen atom, and polishing particle, keeping contact pressure between the wafer and the polishing pad 4000 to 12000Pa, and adjusting temperature of the polishing pad or of the wafer to range 35‹C to 75‹C. A metal polishing method includes the step of: feeding metal polishing liquid(24) to a polishing pad(13) mounted on a polishing jig(12); and rotating the polishing jig to contact the polishing pad to a wafer(23). The metal polishing liquid contains heterocyclic ring compound, organic acid containing second grade or third grade nitrogen atom, and polishing particle whose rate between a major radius and a minor radius is 1.2 to 5.0. The contact pressure between the wafer and the polishing pad ranges 4000 to 12000Pa. The temperature on the surface of the polishing pad or on the wafer ranges 35‹C to 75‹C.

Description

Metal polishing method {METAL POLISHING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of semiconductor devices, and more particularly, to a method of chemical mechanical planarization in a wiring process of a semiconductor device.

BACKGROUND OF THE INVENTION In the development of semiconductor devices represented by semiconductor integrated circuits (hereinafter referred to as "LSI"), miniaturization and high speed have recently required high density and high integration due to miniaturization and stacking of wiring. As a technique for this purpose, various techniques such as chemical mechanical polishing (hereinafter referred to as "CMP") are used. This CMP is an essential technique for the surface planarization of the processed film such as an interlayer insulating film, the formation of a plug, the formation of a buried metal wiring, and the like. See US Patent No. 4,944,836).

The general method of CMP is to attach a polishing pad on a circular polishing platen (platen), dip the surface of the polishing pad into the polishing liquid, press the surface of the substrate (wafer) on the polishing pad, and apply a predetermined pressure (polishing) on the back side thereof. The surface of the base is planarized by mechanical friction generated by rotating both the polishing base and the base under the pressure).

Polishing solutions for metals used in CMP generally contain abrasive grains (eg alumina, silica) and oxidants (eg hydrogen peroxide, persulfate). The basic mechanism is believed to be polishing by oxidizing metal surfaces with oxidants and removing the oxide film with abrasive grains, for example, the Journal of Electrochemlcal Society, 1991, 138. Vol. 11, pp. 3460-3464.

As metals for wiring, tungsten and aluminum have conventionally been used for interconnect structures. However, with the aim of further higher performance, LSI using copper having lower wiring resistance than these metals has been developed. As a method of wiring this copper, the damascene method described in Unexamined-Japanese-Patent No. 2-278822 is known, for example. In addition, a dual damascene method in which a contact hole and a wiring conduit are simultaneously formed in an interlayer insulating film and a metal is embedded in both has been widely used. In the polishing of copper metals, in particular, since the metal is a soft metal, a higher precision polishing technique is required. There is also a demand for a high speed metal polishing means capable of exhibiting high productivity at the same time.

In particular, in recent years, due to miniaturization and high speed of semiconductor devices, higher density and higher integration are required due to the miniaturization and stacking of wirings, and the demand for reducing the dishing phenomenon in the shape of plates being excessively polished due to excessive polishing of the wiring metals is required. It's getting stronger. In addition, a polishing method in which film peeling is unlikely to occur even when an insulating material having a weak mechanical strength is used for the introduction of a future Ultra Low-K insulating material (a dielectric constant of 2.3 or less), that is, the contact pressure between the polished surface of the wafer and the polishing pad And a method of obtaining high polishing speed and low dishing even when polishing under low rotational speed of the surface plate is expected.

Japanese Patent Laid-Open Publication No. 2003-289055 discloses a technique for polishing a metal under conditions such as a wafer polished surface, a contact pressure of a polishing pad, and a rotational speed of a surface plate, which is compatible with both high polishing speed and scratch reduction. The method is described.

In the CMP of the metal wiring process, the present inventors have focused on both high-speed polishing and dishing reduction under conditions in which the polishing surface of the wafer and the contact pressure of the polishing pad and the rotational speed of the surface plate are low. Insufficient.

This invention is made | formed in view of the said problem, and makes it a subject to achieve the following objectives.

That is, an object of the present invention is to provide a high pressure of the surface of the polishing pad or the surface of the polishing surface in contact with the surface to be polished and the polishing pad of the surface to be polished when the object (wafer) is polished. It is to provide a metal polishing method which enables high dishing speed and low dishing even under conditions.

MEANS TO SOLVE THE PROBLEM As a result of earnest examination, the present inventors discovered that the problem could be solved by the following method of this invention, and achieved the said objective.

(1) A metal polishing method for supplying a polishing liquid for metal to a polishing plate on a polishing plate, and rotating the polishing plate to make the polishing pad in relative movement while being in contact with the to-be-polished surface of the polished body, wherein the metal polishing solution is used for the metal. The polishing liquid contains abrasive particles having a ratio of the long diameter to the short diameter (average long diameter / average short diameter) of 1.2 to 5.0, an organic acid containing a secondary nitrogen atom or a tertiary nitrogen atom, and a heterocyclic compound, and the polishing surface and the polishing The contact pressure of the pad is 4000 to 12000 Pa, and the polishing surface is polished under the condition that the temperature of the polishing pad surface to which the surface to be polished or the surface to be polished is 35 ° C. or higher and less than 75 ° C. Metal polishing method characterized in that.

(2) The metal polishing method according to (1), wherein the contact pressure between the surface to be polished and the polishing pad is 7000 to 10000 Pa.

(3) The metal polishing method according to (1) or (2), wherein the average long diameter of the abrasive grains is 30 to 70 nm.

(4) The metal polishing method according to (1), wherein the organic acid containing the secondary nitrogen atom or the tertiary nitrogen atom is represented by the following general formula (A) or the following general formula (B).

    Formula (A) Formula (B)

(5) The metal polishing method according to (1), wherein the heterocycle of the heterocyclic compound is a triazole ring or tetrazole ring.

(6) The metal polishing method according to (1), wherein the heterocyclic compound is selected from the following.

1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diazol Mino-1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole.

(7) The metal polishing method according to (1), wherein the heterocyclic compound is 1H-tetrazole.

(8) The metal polishing method according to (1), further comprising an oxidizing agent.

(9) The metal polishing method according to (1), further comprising at least one organic acid or amino acid in addition to an organic acid containing a secondary nitrogen atom or a tertiary nitrogen atom.

(10) The metal polishing method according to any one of (1) to (9), wherein the concentration of the abrasive grain is 0.1 to 1.5 mass% with respect to the polishing liquid for metal.

On the other hand, as the to-be-polished object, all materials which require flattening in a semiconductor device manufacturing process, such as a wafer in which a conductive material film is formed on a support substrate, and a laminate in which an electrically conductive material film is formed in an interlayer insulating film formed on a wiring formed on a support substrate, are used. Can be enumerated.

According to the present invention, when polishing a polishing object (wafer), the contact pressure of the surface to be polished with the polishing pad, the temperature of the surface of the polishing pad to which the surface to be polished, or the temperature of the surface to be polished are high. It is then possible to provide a metal polishing method which enables a high dishing rate and also a low dishing.

EMBODIMENT OF THE INVENTION Hereinafter, specific embodiment of this invention is described.

A metal polishing method of supplying a metal polishing liquid to a polishing pad on a polishing plate and rotating the polishing plate to make the polishing pad in relative movement while being in contact with the to-be-polished surface of the polished body, wherein the polishing liquid for metal is long in diameter. Containing the abrasive particles having a ratio (average long diameter / average short diameter) of 1.2 to 5.0, an organic acid containing a secondary nitrogen atom or a tertiary nitrogen atom, and a heterocyclic compound, wherein the surface to be polished and the polishing pad The contact pressure is 4000 to 12000 Pa, and the surface of the polishing pad to which the surface to be polished or the temperature of the surface to be polished is polished to 35% or more and less than 75 ° C. Metal polishing method.

By this method, the wafer on which the conductive material film (for example, a metal layer) is formed, for example, can be chemically and mechanically planarized.

Here, in the present invention, the polishing liquid for metal is hereinafter simply referred to as "polishing liquid".

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Metal polishing method

[Polishing device]

First, the apparatus which can implement the metal grinding | polishing method of this invention is demonstrated.

As a polishing apparatus applicable to the present invention, there is provided a general polishing apparatus including a holder holding a to-be-polished body (such as a semiconductor substrate) having a to-be-polished surface, and a polishing plate with a polishing pad (attaching a motor having a variable speed). It can be used, for example, FREX300 (Ebara Seisakusho) can be used.

[Contact Pressure of Polished Surface and Polishing Pad]

In the metal polishing method of the present invention, the contact pressure between the surface to be polished and the polishing pad is polished at 4000 to 12000 Pa, more preferably at 7000 to 10000 Pa. Outside of these ranges, the effects of the present invention, that is, high polishing rate and low dishing are not sufficiently expressed, which is undesirable.

[The temperature of the surface of the polishing pad or the surface of the polishing surface to which the surface to be polished contacts]

In the metal polishing method of the present invention, polishing is performed under conditions where the temperature of the polishing pad surface to which the surface to be polished contacts or the temperature of the surface to be polished (hereinafter referred to as "surface temperature") is 35 ° C or more and less than 75 ° C. It is not preferable because the effect of the present invention is not sufficiently obtained outside these ranges.

(Measurement of surface temperature)

The measurement of the surface temperature may measure the spinning temperature of the surface of the polishing pad in contact with the surface to be polished or the direct spinning temperature of the surface to be polished. 1A and 1B are model diagrams of an apparatus for measuring the surface to be polished during polishing. The measuring method includes a method of arranging a thermal radiation thermometer on the lower surface of the wafer as shown in FIG. 1A, or a method of arranging a thermal radiation thermometer on the upper surface of the wafer as shown in FIG. 1B. You may use it.

Referring to FIG. 1A, an opening 14 for temperature measurement is formed in the polishing pad 13 and the polishing plate 12 disposed in the polishing apparatus 10, and the opening 14 is a radiation thermometer for each rotation period. The polishing surface 12 and the polishing head 22 are rocked and rotated so as to pass through the portion where 16A is provided. The wafer 23 is attached to the polishing head 22, and polishing is performed while supplying the metal polishing liquid (slurry) 24 from the supply port 26 of the metal polishing liquid onto the polishing pad 13. . Thus, when the opening part 14 passes through the part which installed the radiation thermometer 16A, the thermal radiation temperature of the surface of the wafer 23 can be measured with the radiation thermometer 16A. In addition, it is also possible to arrange the radiation thermometer 16B at a predetermined period or at a portion where the wafer 23 is pushed out of the polishing pad 13 during polishing, and measure the surface temperature of the wafer 23 at the bottom. In addition, the temperature of the surface of the polishing pad 13 may be directly measured in order to improve the simplicity of the experiment.

Similarly, as shown in FIG. 1B, the wafer 23 is disposed on the polishing head 22 provided below, the polishing pad 13 fixed to the polishing plate 12 is provided above, and the polishing pad 13 is provided. And the opening 14 for temperature measurement in the polishing plate 12, and the radiation thermometers 16A and 16B on the upper side of the polishing plate 12, which can be measured in the same manner as described above with the surface to be polished upward. Similarly, the polishing wafer surface temperature can be measured.

(Control method of surface temperature)

The surface temperature may be controlled by, for example, controlling the temperature of the polishing surface, the polishing head or the surface to be polished, and the polishing rate of the polishing object. Moreover, you may control by temperature adjustment of the polishing liquid for metals. Or you may control by adjusting content of the abrasive grain in the polishing liquid for metals, the kind of organic acid, and the kind of heterocyclic compound suitably.

Here, as the polishing table, the polishing head or the surface to be polished, for example, a method of controlling the temperature by installing a heating element or a cooling mechanism on the polishing table or the polishing head, the polishing table, the polishing head or the wafer by a heater, a cooler or the like. The method of controlling externally or the method of temperature-controlling the whole room in which the grinding | polishing system containing a grinding | polishing apparatus, a slurry, and pure water, for example, a grinding | polishing apparatus are installed can be illustrated.

As a control method of the polishing speed of a to-be-processed object, the method of controlling by the contact pressure and rotation speed of a polishing head and a to-be-polished surface can be illustrated. By raising this contact pressure and rotation speed, frictional heat increases and surface temperature rises. By lowering the contact pressure and rotation speed, frictional heat is suppressed and surface temperature falls.

As a method of controlling the temperature of the metal polishing liquid, a method of controlling by a temperature control apparatus attached to a supply tank of a metal polishing liquid, a liquid supply pipe, or the like, or a method of controlling the supply system and the polishing system into a constant temperature chamber Can be illustrated.

Further, by controlling the content of the abrasive grains in the polishing liquid for metal, the surface temperature can be controlled by the frictional heat between the abrasive grains and the polished object. In other words, increasing the content of the abrasive particles increases the frictional heat of the polished object to raise the surface temperature, while decreasing the content of the abrasive particles decreases the frictional heat, thereby lowering the surface temperature. Further, by appropriately selecting the type of the organic acid and the type of the heterocyclic compound, the degree of embrittlement promotion by oxidation of the surface to be polished and the formation of the passivation film enable the surface state of the surface to be polished to be adjusted. The surface temperature can be controlled by the frictional heat of the polishing pad.

The surface temperature can be appropriately controlled by the method or the like so as to maintain a predetermined temperature while the surface temperature is measured by a non-contact thermometer. In addition, the surface temperature can be controlled under experimentally determined conditions.

[Method of Supplying Polishing Liquid for Metals]

In this invention, water or aqueous solution can also be diluted and used for the concentrated metal polishing liquid. As the dilution method, for example, a pipe for supplying the concentrated metal polishing liquid and a pipe for supplying water or an aqueous solution may be joined in the middle to be mixed, and a method for supplying the diluted metal polishing liquid to the polishing pad may be exemplified. have. In this case, the mixing is carried out through a narrow passage under pressure, and the liquids collide with each other, the filling of a glass tube or the like is filled in the piping, and the flow of the liquid is separated and joined repeatedly. The method normally performed, such as a method of installing a wing | blade, can be used.

As another dilution method, a pipe for supplying a polishing liquid for metal and a pipe for supplying water or an aqueous solution are independently provided, and a predetermined amount of liquid is supplied to the polishing pad, respectively, for the relative movement of the polishing pad and the surface to be polished. Mixing can also be used in the present invention.

In addition, a method in which a predetermined amount of concentrated polishing liquid for metal and water or an aqueous solution are mixed in one container, diluted to a predetermined concentration, and then supplied to the polishing pad with the mixed solution is also applicable to the present invention.

In addition to these methods, a method of dividing a component to be contained in the polishing liquid for metal into at least two constituent components, adding water or an aqueous solution, and diluting the same to supply the polishing pad can also be used in the present invention. In this case, it is preferable to divide and supply into the component containing an oxidizing agent, and the component containing an acid.

For example, when using an oxidizing agent as one component (A) and an acid, an additive, surfactant, and water as one component (B), and using them, the component (A) and a component ( Dilute and use B). In this case, three pipes each supplying the component (A), the component (B) and water or an aqueous solution are required, and the three pipes are joined to one pipe for supplying the polishing pad and mixed in the pipe. You may combine two piping, and then combine and mix another piping. For example, it is also possible to supply a polishing liquid for metal by mixing a component containing an additive which is difficult to dissolve with another component, lengthening the mixing route to secure a dissolution time, and then combining water or an aqueous pipe. Do.

In addition, the above three pipes may be led to the polishing pad, respectively, to be mixed and supplied by the relative movement of the polishing pad and the surface to be polished, or the mixed liquid may be supplied to the polishing pad after mixing three components in one container. good. Moreover, you may supply dilution water separately to a to-be-polished surface using the metal polishing liquid as a concentrate.

[Abrasive Supply for Metals]

In the metal polishing method of the present invention, the supply amount of the metal polishing liquid to the polishing platen can be 50 to 500 ml / min to stabilize the polishing rate and in-plane uniformity, more preferably 100 to 300 ml / min. Do.

[Polishing Pad]

There is no restriction | limiting in particular in the polishing pad used at the time of performing a chemical mechanical polishing method using the metal polishing liquid of this invention, A non-foaming structure pad may be sufficient, and a foaming structure pad may be sufficient. The former uses a hard synthetic resin bulk material such as a plastic sheet as the polishing pad. In addition, the latter has three types of independent foams (dry foam systems), continuous foams (wet foam systems), and two-layer composite materials (laminated systems), and two-layer composite materials (laminated systems) are particularly preferable. Foaming may be uniform or non-uniform.

Moreover, the thing used for grinding | polishing may contain the particle (for example, ceria, silica, alumina, resin, etc.). The hardness may be either soft or hard, and any one may be used, and it is preferable to use a different hardness for each layer in the laminate system. As a material, nonwoven fabric, artificial leather, polyamide, polyurethane, polyester, polycarbonate, etc. are preferable. Further, lattice spheres / holes / concentric spheres / spiral spheres and the like may be processed on the surface in contact with the surface to be polished.

Next, the polishing liquid for metal is demonstrated.

Metal Polishing Liquid

It is preferable that the polishing liquid for metals used for this invention contains a heterocyclic compound as an essential component, an organic acid, an oxidizing agent, abrasive grains, etc. as an essential component, and is normally formed by disperse | distributing abrasive grains in the aqueous solution formed by melt | dissolving each component. Take the form of a slurry.

Each component contained in the polishing liquid for metal is described in detail below, but each component may be used in one kind or in combination of two or more kinds.

In the present invention, the term "polishing liquid for metal" refers not only to a polishing liquid having a composition (concentration) used for polishing, but also to a polishing concentrate which is diluted and used as necessary at the time of use. When the concentrate is used for polishing, the concentrate is diluted with water or an aqueous solution and used for polishing. The dilution ratio is generally 1 to 20 volume times.

In the present invention, the polishing liquid for metal is 1. In the case of the use liquid diluted with the addition of water when used as a concentrate, 2. The components are mixed in the form of the aqueous solution described in the following paragraph, and water is added as necessary. In the case of diluted use solution, 3. It may be prepared as a use solution.

In any case, the polishing liquid for metal can be applied to the metal polishing method of the present invention.

Next, the component of the polishing liquid for metals which concerns on this invention is demonstrated.

[Polishing Particles]

The polishing liquid for metal used for this invention is an abrasive grain, Comprising: At least 1 abrasive grain (Hereinafter, it is suitably called "specific particle | grains") whose ratio (average long diameter / average short diameter) of the long diameter and short diameter of an abrasive grain is 1.2-5.0. Contains species.

In this invention, a long diameter refers to the largest particle diameter part in a specific particle.

In the present invention, the short diameter refers to the largest particle diameter portion among the diameters intersecting the long diameter in the vertical direction.

In the present invention, as the abrasive particles of the component, among the silicas (precipitated silica, fumed silica, colloidal silica, synthetic silica), colloidal silica or fumed silica is preferable, and colloidal silica is particularly preferable because the polishing rate with respect to the copper-containing metal is high. Especially, colloidal silica which has a cocoon shape is more preferable.

Here, a "cocoon-like shape" refers to a shape in which the center portion or the end of the abrasive grain is concave or a so-called bale-like shape.

A commercially available product can be used as a specific particle | grain, Specifically, for example, a colloidal silica made from Fusoka Chemical Co., Ltd. make a brand name: PL-1SL (long diameter: 15 nm, short diameter: 8 nm, long diameter / short diameter: 1.9), PL-2 ( Long diameter: 25nm, short diameter: 1Onm, long diameter / short diameter: 2.5), PL-3 (long diameter: 35nm, short diameter: 11nm, long diameter / short diameter: 3.1), PL-5 (long diameter: 55nm, short diameter: 14nm, long diameter / short diameter: 3.8), PL-7 (long diameter: 70 nm, short diameter: 17 nm, long diameter / short diameter: 4.2), PL-10 (long diameter: 10 Onm, short diameter: 20 nm, long diameter / short diameter: 5.0) and the like can be preferably used.

Moreover, as a method of obtaining the abrasive grains which have an average long diameter and an average short diameter as prescribed | regulated by this invention, the manufacturing method using the sol-gel method and the separation method by centrifugation are mentioned, for example.

The average long diameter and average short diameter of the abrasive grain used for this invention can be calculated | required by the following method.

That is, using Hitachi High-Technologies Scanning Electron Microscope S4800, the shape of the entire abrasive grain was determined, and then the abrasive grain was observed in the direction in which the long diameter could be confirmed, and the long diameter and the short diameter in any 100 or more abrasive grains. Are measured and calculated from the arithmetic mean, respectively, to be " average long diameter " and " average short diameter " of specific particles in the present invention.

The range of the preferable average long diameter of the abrasive grain whose ratio (average long diameter / average short diameter) of the long diameter and short diameter contained in the metal polishing liquid used for this invention is 1.2-5.0 is 10-200 nm, It is more preferable that it is 30-100 nm. And it is especially preferable that it is 30-70 nm.

In the polishing liquid for metals used in the present invention, a preferable content of the polishing particles having a ratio (average long diameter / average short diameter) of the long and short diameters of the abrasive grains is 1.2 to 5.0 is 0.01 to the total mass of the metal polishing liquid when used. It is -10 mass%, and it is more preferable that it is 0.1-1.5 mass%.

[Organic acid containing secondary nitrogen atom or tertiary nitrogen atom]

The polishing liquid used in the present invention is characterized by containing at least one organic acid (hereinafter referred to as a specific nitrogen-containing organic acid) containing a secondary nitrogen atom or a tertiary nitrogen atom.

In this invention, the specific nitrogen-containing organic acid can illustrate the compound represented by the following general formula (A) or the following general formula (B) as a preferable thing.

    Formula (A) Formula (B)

In the said general formula (A) and said general formula (B), R ^<a> , R <^b> , R <^c> respectively independently represents a C1-C10 alkyl group.

It is preferable that this alkyl group is C1-C8, More preferably, it is C2-C7. In addition, this alkyl group may have a substituent, it may be unsubstituted, and any of linear, branched or cyclic may be sufficient as it. Substituents which can be introduced include -OH, -COOH, -CONH ₂ , -SO ₃ H, and -PO ₃ H ₂ And the like can be listed as preferred. In addition, the introduced substituents may be bonded to each other to form a ring structure.

On the other hand, this alkyl group also includes those in which part of the carbon atoms constituting the alkyl group is substituted with another atom (for example, a nitrogen atom).

Specific examples of the organic acid containing a preferable secondary or tertiary nitrogen atom include the following compounds [Example Compounds (I-1) to (I-21)]. However, the specific nitrogen-containing organic acid preferable in this invention is not limited to these exemplary compounds.

Among these specific nitrogen-containing organic acids in the present invention, these may more preferably include compounds I-3, I-5, I-7, I-10, I-21 and the like.

In addition, in this invention, specific nitrogen-containing organic acid may be used independently and may be used together 2 or more types.

These specific nitrogen-containing organic acids may be commercially available, in addition to being normally synthesized.

In the present invention, the amount of the specific nitrogen-containing organic acid to be added is preferably 0.005 to 0.5 mol, more preferably 0.005 to 0.3 mol in 1 L of the polishing liquid for metal when used for polishing. It is especially preferable to set it as mol-0.1 mol. That is, the addition amount of the specific nitrogen-containing organic acid is preferably 0.0005 mol or more from the point of increasing the polishing rate, and 0.5 mol or less is preferable from the point of suppressing dishing.

Heterocyclic Compounds

The polishing liquid for metals of the present invention contains at least one heterocyclic compound as a compound for forming a passivation film on the metal surface to be polished.

Here, a "heterocyclic compound" is a compound having a heterocycle containing one or more hetero atoms. Heteroatom means an atom other than a carbon atom or a hydrogen atom. A heterocycle means a cyclic compound having at least one hetero atom. Heteroatoms refer only to atoms which form a constituent part of a heterocyclic ring system and are located external to the ring system, or are separated from the ring system by at least one non-conjugated single bond, or appear to be part of a new substituent of the ring system Does not mean.

The hetero atom is preferably a nitrogen atom, a sulfur atom, an oxygen atom, a selenium atom, a tellurium atom, a person atom, a silicon atom and a boron atom, more preferably a nitrogen atom, a sulfur atom, an oxygen atom and a selenium atom, particularly preferably Preferably it is a nitrogen atom, a sulfur atom, and an oxygen atom, Most preferably, they are a nitrogen atom and a sulfur atom.

First, the heterocycle which becomes a mother nucleus is described.

The raw number of the heterocyclic ring of the heterocyclic compound used in the present invention is not particularly limited, and may be a monocyclic compound or a polycyclic compound having a condensed ring. The raw water in the case of monocyclic is preferably 3 to 8, more preferably 5 to 7, and particularly preferably 5 and 6. Further, the ring number in the case of having a condensed ring is preferably 2 to 4, more preferably 2 or 3.

The following can be illustrated specifically as these heterocycles. However, it is not limited to these.

Pyrrole ring, thiophene ring, furan ring, pyran ring, thiopyran ring, imidazole ring, pyrazole ring, thiazole ring, isothiazole ring, oxazole ring, isoxazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyrida Ring-ring, pyrrolidine ring, pyrazolidine ring, imidazolidine ring, isoxazolidine ring, isothiazolidine ring, piperidine ring, piperadine ring, morpholin ring, thiomorpholin ring, croman ring, thiochroman ring, iso Chromman ring, isothiochroman ring, indolin ring, isoindolin ring, pyridine ring, indolidine ring, indole ring, indazole ring, purine ring, quinoline ring, isoquinoline ring, quinoline ring, naphthyridine ring, phthalazine ring , Quinoxaline ring, quinazoline ring, cinnoline ring, putridine ring, acridine ring, perimidine ring, phenanthroline ring, carbazole ring, carboline ring, phenazine ring, antithyridine ring, thiadiazole ring , Oxadiazole ring, triazine ring, triazole ring, tetrazole ring, benzimidazole ring, benzoxazole Ring, benzthiazole ring, benzthiadiazole ring, benzfuroxane ring, naphthoimidazole ring, benztriazole ring, tetraazainden ring and the like can be enumerated, more preferably triazole ring and tetrazole ring. .

Next, the substituent which the said heterocycle can have is described.

In the present invention, when a specific portion is referred to as a "group", it means that the portion may not be substituted by itself, or may be substituted with one or more (up to the maximum possible number) substituents. For example, an "alkyl group" means a substituted or unsubstituted alkyl group.

Substituents which can be used as the heterocyclic compound used in the present invention may include the following ones, for example.

However, it is not limited to these.

That is, a halogen atom (fluorine atom, chlorine atom, bromine atom, or iodine atom), an alkyl group (it may be a linear, branched or cyclic alkyl group, and may be a polycyclic alkyl group, such as a bicycloalkyl group, and may contain an active methine group), an alkenyl group , Alkynyl group, aryl group, heterocyclic group (regardless of the position to be substituted), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group (as carbamoyl group having a substituent, for example, N- Hydroxycarbamoyl group, N-acylcarbamoyl group, N-sulfonylcarbamoyl group, N-carbamoylcarbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group), carbazoyl group, carboxyl group or its Salt, oxaryl group, oxamoyl group, cyano group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing ethylene oxy or propylene oxy groups repeatedly), aryl oxy, heterocyclic Period, acyloxy group, (alkoxy or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl or heterocyclic) amino group, acylamino group, sulfonamido group, ureido group, thiouido group , N-hydroxyureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, amonio group, oxamoylamino group, N- ( Alkyl or aryl) sulfonyl ureido groups, N-acyl ureido groups, N-acylsulfamoylamino groups, hydroxyamino groups, nitro groups, heterocyclic groups containing quaternized nitrogen atoms (e.g., pyridinio groups, imida) Joolio, quinoliniio, isoquinolini), isocyano group, imino group, mercapto group, (alkyl, aryl or heterocyclic) thio group, (alkyl, aryl or heterocyclic) dithio group, (alkyl or Aryl) sulfonyl group, ( Chel or aryl) sulfinyl group, sulfo group or salt thereof, sulfamoyl group (as sulfamoyl group having a substituent, for example, N-acyl sulfamoyl group, N-sulfonyl sulfamoyl group) or salt thereof, phosphino group, Phosphinyl group, phosphinyloxy group, phosphinylamino group, a silyl group, etc. can be mentioned.

On the other hand, an active methine group means a methine group substituted with two electron withdrawing groups, and an electron withdrawing group means, for example, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group, and sulfamomo. Diary, a trifluoromethyl group, a cyano group, a nitro group, and a carbonimidoyl group are meant. The two electron withdrawing groups may be bonded to each other to have a cyclic structure. The salt means organic cations such as cations such as alkali metals, alkaline earth metals and heavy metals, and ammonium ions and phosphonium ions.

Among these, preferable substituents include, for example, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms or iodine atoms), alkyl groups (linear, branched or cyclic alkyl groups, and may be polycyclic alkyl groups such as bicycloalkyl groups, and include active methine groups). Alkenyl group, alkynyl group, aryl group, heterocyclic group (regardless of the position to be substituted), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group, N-hydroxycarbamo Diary, N-acyl carbamoyl group, N-sulfonyl carbamoyl group, N-carbamoyl carbamoyl group, thiocarbamoyl group, N-sulfamoylcarbamoyl group, carbazoyl group, oxaryl group, oxamoyl group, sia Furnace group, carbonimidoyl group, formyl group, hydroxy group, alkoxy group (including groups containing ethylene oxy or propylene oxy groups repeatedly), aryl oxy, heterocyclic oxy, acyloxy, (alkoxy Or aryl oxy) carbonyloxy group, carbamoyloxy group, sulfonyl oxy group, (alkyl, aryl or heterocyclic) amino group, acylamino group, sulfonamide group, ureido group, thioureido group, N-hydroxy ureido group, imido group , (Alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, ammonio group, oxamoylamino group, N- (alkyl or aryl) sulfonyl ureido group, N Heterocyclic groups containing acylureido groups, N-acylsulfamoylamino groups, hydroxyamino groups, nitro groups, quaternized nitrogen atoms (e.g., pyridinio groups, imidazolio groups, quinolini groups, isoquinolins) Niogi), isocyano group, imino group, mercapto group, (alkyl, aryl or heterocyclic) thio group, (alkyl, aryl or heterocyclic) dithio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulphi Nyl group, sulfo group or The salt, sulfamoyl group, N-acyl sulfamoyl group, N-sulfonyl sulfamoyl group or its salt, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, a silyl group, etc. can be mentioned. Meanwhile, the active methine group herein means a methine group substituted with two electron-withdrawing groups, and the electron-withdrawing group includes acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, Trifluoromethyl group, cyano group, nitro group, and carbonimidoyl group.

More preferably, for example, a halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom), an alkyl group (linear, branched or cyclic alkyl group, may be a polycyclic alkyl group such as a bicycloalkyl group, or may contain an active methine group Good), an alkenyl group, an alkynyl group, an aryl group, and a heterocyclic group (regardless of the position substituted) can be mentioned.

In addition, two of the above substituents may be jointly combined to form a ring (aromatic or non-aromatic hydrocarbon ring or heterocyclic ring. These may be further combined to form a polycyclic condensed ring. For example, a benzene ring, a naphthalene ring, an anthracene ring, and a phen) Nanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyrida Tricyclic, indolidine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring , Carbazole ring, phenanthridine ring, acridine ring, phenanthroline ring, thianthrene ring, chromen ring, xanthene ring, phenoxatiin ring, phenothiazine ring, and phenadidine ring) may be formed). .

Although the specific example of the heterocyclic compound which can be used especially preferable for this invention is not limited to these, The following can be enumerated.

Ie 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5 -Diamino-1,2,3-triazole, l, 2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole .

The heterocyclic compound used for this invention may be used independently and may be used together 2 or more types. In addition, the heterocyclic compound used for this invention may use a commercial item other than what can be synthesize | combined normally.

As for the addition amount of the heterocyclic compound used for this invention, when it is used for grinding as a total amount, 0.0001-1.0 mol is preferable in 1 L of metal polishing liquids (that is, the metal polishing liquid after dilution, when diluting in water or aqueous solution), Preferably it is 0.0005-0.5 mol, More preferably, it is 0.0005-0.05 mol.

[Oxidizer]

It is preferable that the polishing liquid for metals of this invention contains the compound (oxidizing agent) which can oxidize the metal of a grinding | polishing object.

Specifically, hydrogen peroxide, peroxide, nitrate, iodide, periodate, hypochlorite, chlorite, chlorate, perchlorate, persulfate, bichromate, permanganate, ozone water and silver (II) salt, iron (III) salt Although it can illustrate, hydrogen peroxide can be used more suitably.

The addition amount of the oxidizing agent is preferably from 0.003 mol to 8 mol, more preferably from 0.03 mol to 6 mol, and particularly preferably from 0.1 mol to 4 mol, in 1 liter of the metal polishing liquid used for polishing. That is, the addition amount of the oxidizing agent is preferably 0.003 mol or more in terms of sufficient metal oxidation to ensure a high CMP rate, and 8 mol or less in terms of preventing roughening of the surface to be polished.

[Other organic acids]

It is preferable that the polishing liquid for metals concerning this invention contains at least 1 type of organic acid or amino acid other than a specific nitrogen-containing organic acid. The other organic acid is not an oxidizing agent of metal, but has an action of promoting oxidation, adjusting pH, and buffering agent.

As an organic acid, a water-soluble thing is preferable. More suitable are those selected from the following groups. Formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethyl butyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethyl hexanoic acid, benzoic acid, glycolic acid, salicylic acid, glycerin acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, Lactic acid, hydroxyethyliminoic acid, iminoacetic acid, dihydroxyethylglycine, salts such as ammonium salts and alkali metal salts thereof, sulfuric acid, nitric acid, ammonia, ammonium salts, and mixtures thereof. Among these, formic acid, malonic acid, malic acid, tartaric acid, citric acid, hydroxyethyliminoiacetic acid, iminoiacetic acid, dihydroxyethylglycine and the like are preferable.

As an amino acid, water solubility is preferable. More suitable are those selected from the following groups.

Glycine, L-alanine, β-alanine, L-2-amino butyric acid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine, L-alloisoleucine, L-phenylalanine, L- Proline, sarcosine, L-ornithine, L-lysine, taurine, L-serine, L-threonine, L-allothroonine, L-homoserine, L-tyrosine, 3,5-diodo-L-tyrosine, β -(3,4-dihydroxyphenyl) -L-alanine, L-thyroxine, 4-hydroxy-L-proline, L-cysteine, L-methionine, L-ethionine, L-lanthionine, L -Cystionine, L-cystine, L-cystine acid, L-aspartic acid, L-glutamic acid, S- (carboxymethyl) -L-cystine, 4-amino butyric acid, L-asparagine, L-glutamine, azaserine, L -Arginine, L-Canabanine, L-Citrulline, δ-Hydroxy-L-Lysine, Creatine, L-Kynurenine, L-Histidine, 1-Methyl-L-Histidine, 3-Methyl-L-Histidine, Elgoti Oneine, L-tryptophan, actinomycin C1, apamin, angiotensin I, angiotensin II and antipine Amino acids.

Especially for malic acid, tartaric acid, citric acid, glycine, glycolic acid, β-alanine, hydroxyethyliminoacetic acid, iminoacetic acid, and dihydroxyethylglycine, the etching rate can be effectively suppressed while maintaining the practical CMP rate. It is preferable at the point that it is.

Surfactant / Hydrophilic Polymer

The polishing liquid for metals of the present invention may further contain other components, and examples thereof include surfactants, lipophilic polymers, and other additives.

It is preferable that the polishing liquid of the present invention contains a surfactant or a hydrophilic polymer.

Both the surfactant and the hydrophilic polymer have a function of lowering the contact angle of the surface to be polished, and have a function of promoting uniform polishing. As surfactants and hydrophilic polymers that can be used, those selected from the following groups are preferable.

Examples of the anionic surfactants include carboxylates, sulfonates, sulfuric acid ester salts, and phosphate ester salts, and as cationic surfactants, aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium chloride, benzethonium chloride and pyridinium salts, and the like. Dazolinium salts can be enumerated, and carboxybetaine type, amino carboxylate, imidazolinium betaine, lecithin, alkylamine oxide can be enumerated as an amphoteric surfactant, and ether type, ether ester type as nonionic surfactant. , Ester type and nitrogen-containing type may be enumerated, and fluorine-based surfactant may be enumerated.

Examples of the hydrophilic polymer include polyglycols such as polyethylene glycol, polysaccharides such as polyvinyl alcohol, polyvinylpyrrolidone, and arginic acid, and carbon acid-containing polymers such as polymethacrylic acid.

On the other hand, it is preferable that the acid or its ammonium salt is free from contamination with alkali metals, alkaline earth metals, halides, and the like. Among the above exemplary compounds, cyclohexanol, polyammonium acrylate salt, polyvinyl alcohol, succinate amide, polyvinylpyrrolidone, polyethylene glycol, and polyoxyethylene polyoxypropylene block polymer are more preferable.

As a weight average molecular weight of these surfactant and a hydrophilic polymer, 500-100000 are preferable and 2000-500000 are especially preferable.

The amount of the surfactant and / or hydrophilic polymer added is preferably 0.001 to 10 g, more preferably 0.01 to 5 g, particularly preferably 0.1 to 3 g, in 1 L of the polishing liquid for metal when used for polishing as a total amount. Do.

pH adjuster

In order to make the polishing liquid for metals of the present invention a predetermined pH, an alkali agent, a buffer, and an inorganic acid can be added as a pH adjuster.

Alkali agents (and buffers) include nonmetallic alkali agents such as alkanolamines such as organic ammonium hydroxides such as ammonium hydroxide and tetramethylammonium hydroxide, diethanolamine, triethanolamine and triisopropanolamine, sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. And carbonates such as alkali metal hydroxides, sodium carbonate, trisodium phosphate, borate, tetraborate, hydroxy benzoate and the like.

Particularly preferred alkali agents are ammonium hydroxide, potassium hydroxide, lithium hydroxide and tetramethylammonium hydroxide.

Examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, phosphoric acid, and the like. Among these, phosphoric acid and sulfuric acid are preferable.

The pH adjusting agent may be added in an amount such that the pH is maintained in a preferred range. The amount of the pH adjuster may be 0.000 l mol to 1.0 mol, and more preferably 0.003 mol to 0.5 mol in 1 liter of the polishing liquid for metal when used for polishing.

3-12 are preferable, as for pH of the polishing liquid for metals at the time of use for grinding | polishing, More preferably, it is 4-9, Especially 5-8 are preferable. Within this range, the polishing liquid for metals used in the present invention exhibits particularly excellent effects. The pH of the polishing liquid is adjusted to the above preferred range by the pH adjuster.

[Chelating agent]

The polishing liquid for metals which concerns on this invention may contain a chelating agent (namely, a hard water softener) as needed in order to reduce the bad influence, such as multivalent metal ions mixed.

As the chelating agent, a general hard water softener or a flexible compound thereof, which is a calcium or magnesium precipitation inhibitor, may be used in combination of two or more thereof as necessary.

The amount of the chelating agent added may be an amount sufficient to contain metal ions such as polyvalent metal ions to be mixed. For example, the chelating agent is added in an amount of 0.0003 mol to 0.07 mol in 1 liter of the polishing liquid for metal when used for polishing.

<Human body>

Next, a polishing object (substrate, wafer) to be polished in the polishing method of the present invention will be described.

[Wired metal material]

In the present invention, the polished body is a substrate (wafer) having a wiring made of copper or a copper alloy, and a copper alloy containing silver is suitable among the copper alloys. The silver content contained in a copper alloy exhibits the outstanding effect in 10 mass% or less, Furthermore, 1 mass% or less, and exhibits the most outstanding effect in the copper alloy of 0.00001-0.1 mass%.

[Thickness of wiring]

In the present invention, the to-be-polished body has a half pitch in the DRAM device system, for example, preferably has a wiring of 0.15 µm or less, more preferably 0.10 µm or less, still more preferably 0.08 µm or less.

On the other hand, in an MPU device system, it is preferable to have wiring of 0.12 micrometer or less, More preferably, it is 0.09 micrometer or less, More preferably, it is 0.07 micrometer or less.

The polishing liquid for metals used in the present invention with respect to the polished body having such a wiring exhibits particularly excellent effects.

[Barrier metal]

In the present invention, a barrier layer for preventing the diffusion of copper is formed between the copper wiring and the insulating film in the polished body, and as the barrier layer, a metal material having a low resistance, for example, Ru, TiN, TiW, Ta, TaN, W, WN This is preferable, and Ta and TaN are especially preferable among these.

[Interlayer Insulation Film]

As said interlayer insulation film, it is preferable to have the characteristic of dielectric constant of 2.6 or less, For example, a silicon film, an organic interlayer insulation film, etc. can be mentioned, It is preferable to use the silicon film which doped carbon especially.

EXAMPLE

Hereinafter, an Example demonstrates this invention. This invention is not limited by these Examples.

[Examples 1-1 to 1-4, Comparative Examples 1-1, 1-2]

(Preparation of polishing liquid for metal)

Abrasive particles: 3 g / l of cocoon-type non-spherical abrasive colloidal silica (average long diameter, average short diameter and their ratios are shown in Table 1)

Specific nitrogen-containing organic acids: (compound shown in Table 1) 0.25 mol / l

Other organic acids: 0.24 mol / l dihydroxyethylglycine

Heterocyclic Compound: (Compound shown in Table 1) 17 mmol / L

Oxidizer: Hydrogen Peroxide 9.0g / ℓ

Pure water added: 1000 ml

pH (adjusted with ammonia water and sulfuric acid) 6.5

-Economic Method of Polishing Particles-

Adjustment of the average long diameter and average short diameter of the abrasive grain shown in Table 1 is by the separation method by centrifugation.

 (Polishing test)

Polishing was carried out under the following conditions, and the polishing rate and dishing were evaluated.

Polishing Equipment: FREX300 (Ebaraseisakusho)

Polished body (wafer):

(1) for calculating the polishing rate; Blanket wafer 300 mm in diameter with a Cu film 1 μm thick on silicon substrate

(2) dishing evaluation; 300mm diameter copper wiring wafer

(Pattern wafer: mask pattern 754CMP (ATDF))

Polishing pad: IC1400K-XY Groove (Nitahasu Corporation)

Polishing condition;

Polishing pressure (contact pressure between the polished surface and the polishing pad): shown in Table 1

Polishing liquid supply rate: 200 ml / min

Polishing plate rotation speed: 108rpm

Polishing head rotation speed: 95rpm

 (Assessment Methods)

Average long diameter, average short diameter of the abrasive grain

100 particles were measured in a transmission electron microscope mode using Hitachi High-Technologies S4800 SEM and averaged.

Contact pressure

Measured by load cell.

Surface temperature

Surface temperature was measured using a radiation temperature measuring device (NEC Sansei TH7102).

Polishing Speed

The blanket wafer of (1) was polished for 60 seconds, and the metal film thicknesses before and after polishing were calculated in terms of the above resistance values at 49 equally spaced points on the wafer surface, and the average value of the values obtained by dividing them by the polishing time was obtained. The polishing rate was taken.

Dishing

In addition to the time until the copper of the non-wiring part is completely polished with respect to the pattern wafer of (2), only 20% of the time is additionally polished and the step of the line and space part (line 100 m, space 100 m) Was measured with a contact stepmeter DektakV320-Si (manufactured by Veeco).

The surface temperatures of Examples 1-1 to 1-4 and Comparative Examples 1-1 and 1-2 were controlled by adjusting the average long diameter and average short diameter of the abrasive grains.

Table 1 shows the results.

Average long diameter of the abrasive grain (nm) Average diameter of abrasive grain (nm) Average Length / Average Short Diameter Nitrogen-containing organic acid Heterocyclic compounds Contact pressure (Pa) Surface temperature (℃) Polishing rate (nm / min) Dishing (nm) Example 1-1 50 41 1.22 I-5 1H-tetrazol 9000 45 622 47 Example 1-2 50 20 2.50 I-5 1H-tetrazol 9000 42 698 38 Example 1-3 50 14 3.57 I-5 1H-tetrazol 9000 50 721 36 Example 1-4 50 10 5.00 I-5 1H-tetrazol 9000 52 679 44 Comparative Example 1-1 50 47 1.06 I-5 1H-tetrazol 9000 34 313 145 Comparative Example 1-2 50 8 6.25 I-5 1H-tetrazol 9000 75 512 123

As apparent from Table 1, it can be seen that Examples 1-1 to 1-4 satisfying the requirements of the present invention exhibit high polishing speed and low dishing. However, if the average long diameter and average short diameter of the abrasive grains of Comparative Example 1-1 and Comparative Example 1-2 are out of the range prescribed | regulated by this invention, a polishing rate will fall and dishing will worsen.

[Examples 2-1, 2-2, Comparative Examples 2-1, 2-2]

Except having changed the contact pressure of the to-be-polished surface and polishing pad into the conditions shown in Table 2 using Example 1, it carried out each polishing test similarly to Example 1, and evaluated the polishing rate and dishing.

In addition, the surface temperature of Example 2-1, 2-2, Comparative Examples 2-1, 2-2 was controlled by adjusting the contact pressure of a to-be-polished surface and a polishing pad.

The results are shown in Table 2 below.

Average long diameter of the abrasive grain (nm) Average diameter of abrasive grain (nm) Average Length / Average Short Diameter Nitrogen-containing organic acid Heterocyclic compounds Contact pressure (Pa) Surface temperature (℃) Polishing rate (nm / min) Dishing (nm) Example 2-1 50 14 3.57 I-5 1H-tetrazol 7000 36 615 33 Example 1-3 50 14 3.57 I-5 1H-tetrazol 9000 50 721 36 Example 2-2 50 14 3.57 I-5 1H-tetrazol 10000 65 783 55 Comparative Example 2-1 50 14 3.57 I-5 1H-tetrazol 3000 30 305 120 Comparative Example 2-2 50 14 3.57 I-5 1H-tetrazol 13000 78 890 150

As apparent from Table 2, it can be seen that Examples 2-1, 2-2 and 1-3, which satisfy the requirements of the present invention, exhibit high polishing speed and low dishing. However, as in Comparative Example 2-1, when the contact pressure is lower than the range specified in the present invention, it can be seen that the polishing rate decreases and the dishing also deteriorates. In addition, when the contact pressure is higher than the range prescribed | regulated by this invention like the comparative example 2-2, although a polishing rate shows a high value, it turns out that dishing worsens.

[Example 3-1, Comparative Examples 3-1 to 3-4]

Except having changed the organic acid to the conditions shown in Table 3 using Example 1, it carried out the polishing test similarly to Example 1, and evaluated the polishing rate and dishing.

In addition, the surface temperature of Example 3-1 and Comparative Examples 3-1 to 3-4 was controlled by the kind of specific nitrogen-containing organic acid.

The results are shown in Table 3 below.

Average long diameter of the abrasive grain (nm) Average diameter of abrasive grain (nm) Average Length / Average Short Diameter Specific nitrogen-based organic acids or organic acids Heterocyclic compounds Contact pressure (Pa) Surface temperature (℃) Polishing rate (nm / min) Dishing (nm) Example 1-3 50 14 3.57 I-5 1H-tetrazol 9000 50 721 36 Example 3-1 50 14 3.57 I-7 1H-tetrazol 9000 47 694 42 Comparative Example 3-1 50 47 1.06 Oxalic acid 1H-tetrazol 9000 30 250 250 Comparative Example 3-2 50 8 6.25 Oxalic acid 1H-tetrazol 9000 78 512 355 Comparative Example 3-3 50 14 3.57 Oxalic acid 1H-tetrazol 9000 82 620 263 Comparative Example 3-4 50 14 3.57 Malic acid 1H-tetrazol 9000 79 572 311

As apparent from Table 3, it can be seen that Examples 1-3 and Examples 3-1 satisfying the requirements of the present invention exhibit high polishing speed and low dishing. However, it can be seen that the polishing liquid for a metal which does not contain the specific nitrogen-containing organic acid specified in the present invention decreases the polishing rate and deteriorates dishing.

[Examples 4-1, 4-2, Comparative Examples 4-1, 4-2]

A polishing liquid was prepared in the same manner as in Example 1-3 of Example 1 except that the concentration of the abrasive grains in Example 1 was changed to the amount shown in Table 4, and the polishing test was carried out as in Example 1, respectively. The polishing rate and dishing were evaluated.

In addition, the surface temperature of Example 4-1, 4-2, and Comparative Examples 4-1, 4-2 was controlled by adjusting content of abrasive grain.

The results are shown in Table 4 below.

Average long diameter of the abrasive grain (nm) Average diameter of abrasive grain (nm) Average Length / Average Short Diameter Abrasive particle concentration (mass%) Specific nitrogenous acid Heterocyclic compounds Contact pressure (Pa) Surface temperature (℃) Polishing rate (nm / min) Dishing (nm) Example 4-1 50 14 3.57 0.5 I-5 1H-tetrazol 9000 36 550 36 Example 1-3 50 14 3.57 0.8 I-5 1H-tetrazol 9000 50 721 36 Example 4-2 50 14 3.57 1.2 I-5 1H-tetrazol 9000 65 756 58 Comparative Example 4-1 50 14 3.57 0.04 I-5 1H-tetrazol 9000 30 285 123 Comparative Example 4-2 50 14 3.57 1.6 I-5 1H-tetrazol 9000 78 865 154

As apparent from Table 4, it can be seen that Examples 4-1, 4-2 and 1-3, which meet the requirements of the present invention, exhibit high polishing rates and low dishing. However, as in Comparative Example 4-1, when the concentration of the abrasive grains is lower than the range specified in the present invention, it can be seen that the polishing rate decreases and the dishing also deteriorates. Moreover, when the density | concentration of abrasive grain is higher than the range prescribed | regulated by this invention, although a grinding | polishing rate shows a high value, it turns out that dishing worsens. That is, it turns out that the effect of this invention is not exhibited except the range of 0.1-1.5 mass% of abrasive grains.

In each test item, the temperature of the to-be-polished surface was measured using the method mentioned above. Comparing Tables 1-4, it turns out that the temperature of the to-be-polished surface which achieves high polishing rate and low dishing is the optimal range of 35 degreeC or more and less than 75 degreeC.

1A and 1B show model diagrams of an apparatus for measuring the surface temperature of a wafer during polishing.

Claims (10)

A metal polishing method for supplying a polishing liquid for metal to a polishing pad on a polishing platen and rotating the polishing plate to make the polishing pad in relative movement while polishing the polishing pad in contact with the to-be-polished surface of the polished body. The polishing liquid for metal contains abrasive particles having a ratio of the long diameter to the short diameter (average long diameter / average short diameter) of 1.2 to 5.0, an organic acid containing a secondary nitrogen atom or a tertiary nitrogen atom, and a heterocyclic compound; The contact pressure of the to-be-polished surface and the said polishing pad is 4000-12000Pa, and the temperature of the said polishing pad surface which the said to-be-polished surface contacts, or the temperature of the to-be-polished surface is 35 degreeC or more and less than 75 degreeC, A metal polishing method comprising polishing a surface to be polished. The method of claim 1, The contact pressure between the surface to be polished and the polishing pad is 7000 to 10000 Pa, characterized in that the metal polishing method. The method of claim 1, The average long diameter of the said abrasive grain is 30-70 nm, The metal polishing method characterized by the above-mentioned. The method of claim 1, The organic acid containing the secondary nitrogen atom or tertiary nitrogen atom is represented by the following general formula (A) or the following general formula (B).

   Formula (A) Formula (B) The method of claim 1, The heterocycle of the heterocyclic compound is a triazole ring or tetrazole ring, characterized in that the metal polishing method. The method of claim 1, The heterocyclic compound is selected from the following metal polishing method. 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 1,2,3-triazole, 4-amino-1,2,3-triazole, 4,5-diazol Mino-1,2,3-triazole, 1,2,4-triazole, 3-amino-1,2,4-triazole, 3,5-diamino-1,2,4-triazole. The method of claim 1, The heterocyclic compound is a metal polishing method, characterized in that 1H- tetrazole. The method of claim 1, Metal polishing method further comprises an oxidizing agent. The method of claim 1, And at least one organic acid or amino acid in addition to the organic acid containing the secondary nitrogen atom or the tertiary nitrogen atom. The method according to any one of claims 1 to 9, The concentration of the said abrasive grain is 0.1-1.5 mass% with respect to the said metal polishing liquid, The metal polishing method characterized by the above-mentioned.

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