WO2011152356A1

WO2011152356A1 - Polishing agent and polishing method

Info

Publication number: WO2011152356A1
Application number: PCT/JP2011/062387
Authority: WO
Inventors: 竹宮　聡; 靖之高木
Original assignee: 旭硝子株式会社
Priority date: 2010-06-03
Filing date: 2011-05-30
Publication date: 2011-12-08
Also published as: TW201202402A; JP2013165088A

Abstract

Disclosed is a polishing agent for chemically and mechanically polishing a surface to be polished in the production of a semiconductor integrated circuit device. The polishing agent contains: abrasive grains; an oxidizing agent; a protective film-forming agent; an acid; an amine having a hydrocarbon group that is selected from among an alkyl group, an aryl group and an aryl-substituted alkyl group and has 6-20 carbon atoms; and water.

Description

Abrasive and polishing method

The present invention relates to an abrasive used in a manufacturing process of a semiconductor integrated circuit device (hereinafter sometimes referred to as a semiconductor device) and a polishing method. More particularly, the present invention relates to an abrasive for chemical mechanical polishing suitable for forming and planarizing a buried metal wiring, and a polishing method using the same.

In recent years, with the higher integration and higher functionality of semiconductor integrated circuits, development of microfabrication technology for miniaturization and higher density has been demanded. In a semiconductor device manufacturing process, particularly a multilayer wiring forming process, a technique for planarizing an interlayer insulating film and embedded wiring is important. That is, as the wiring becomes multi-layered due to miniaturization and high density of the semiconductor manufacturing process, the surface unevenness of each layer tends to increase, and problems such as the step exceeding the depth of focus of lithography tend to occur. In order to prevent this problem, high planarization technology in the multilayer wiring formation process is important.

As a wiring material, copper has attracted attention because of its low specific resistance and superior electromigration resistance compared to conventionally used aluminum alloys. Copper has a low vapor pressure of its chloride gas, and it is difficult to process into a wiring shape by reactive ion etching (RIE), so a damascene method is used to form wiring. This is because a groove pattern for wiring or a recess such as a via is formed in the insulating layer, and then a barrier layer is formed, and then copper is deposited by sputtering or plating so as to be embedded in the groove, and then other than the recess Removing excess copper layer and barrier layer by chemical mechanical polishing (CMP: Chemical Mechanical Polishing, hereinafter referred to as CMP) until the surface of the insulating layer is exposed, and forming a buried metal wiring It is. In recent years, a dual damascene method in which a copper wiring in which copper is embedded in a concave portion and a via portion is formed at the same time has become mainstream.

In the formation of such a copper buried wiring, a barrier layer made of a tantalum compound such as tantalum, tantalum alloy or tantalum nitride is formed in order to prevent diffusion of copper into the insulating layer. Therefore, it is necessary to remove the exposed barrier layer by CMP except for the wiring portion where copper is embedded. However, since the barrier layer is very hard compared to copper, a sufficient polishing rate cannot often be obtained. Therefore, as shown in FIG. 1, a two-step polishing method has been proposed which includes a first polishing step for removing an excess metal wiring layer and a second polishing step for removing an excess barrier layer.

FIG. 1 is a cross-sectional view showing a method of forming a buried wiring by CMP. FIG. 1 (a) is before polishing, FIG. 1 (b) is after the first polishing step for removing the excess metal wiring layer, and FIG. 1 (c) is in the middle of the second polishing step for removing the excess barrier layer. FIG. 1 (d) shows the state after the second polishing step. When a low dielectric constant material is used for the insulating layer, a cap layer made of an insulating material such as silicon dioxide may be formed between the insulating layer and the barrier layer. FIG. 1A to FIG. 1D illustrate the case where there is a cap layer. When the insulating layer is not a layer made of a low dielectric constant material, the cap layer may not be provided.

In the formation of the buried wiring, first, as shown in FIG. 1A, a groove for forming the buried wiring is formed in the insulating layer 2 on the substrate 1. Next, after forming the cap layer 3, the barrier layer 4 and the metal wiring layer 5 in this order on the insulating layer 2 in which the groove is formed, an excess portion of the metal wiring layer 5 is removed in a first polishing step. Next, in the second polishing step, an excess portion of the barrier layer 4 is removed. Usually, after completion of the first polishing process, the metal wiring layer 5 called dishing 6 is reduced as shown in FIG. Therefore, in the second polishing step, as shown in FIG. 1 (c), the excess portion of the barrier layer 4 is completely removed, the cap layer 3 is further removed, and as shown in FIG. 1 (d), If necessary, it is necessary to cut the insulating layer 2 so as to have the same height (level) as the metal wiring layer 5 to achieve a high level of flatness. Thus, the copper buried wiring 7 is formed.

It is not always necessary to remove the cap layer 3, but leaving the cap layer 3 having a higher dielectric constant than that of the insulating layer 2 leads to an increase in the overall dielectric constant. Good characteristics. FIG. 1D shows a state in which the cap layer 3 is completely removed and flattened.

In such flattening, CMP using a conventional abrasive has a problem that dishing and erosion of copper embedding (metal wiring layer 5) increase. Here, dishing refers to a state in which the metal wiring layer 5 is excessively polished and the central portion is depressed as indicated by reference numeral 6 in FIG. 1C and FIG. 2, and is likely to occur in a wide wiring portion. . Erosion is likely to occur in thin wiring portions or dense wiring portions. As shown by reference numeral 8 in FIG. 2, the erosion is an insulating layer of the wiring portion as compared with the insulating layer portion (Global portion) 9 having no wiring pattern. 2 is a phenomenon in which the insulating layer 2 is partially thinned due to excessive polishing. That is, an erosion 8 portion polished further than the polishing portion 10 of the global portion 9 is generated. In FIG. 2, the cap layer 3 and the barrier layer 4 are not shown.

When the conventional polishing agent is used, the polishing rate of the barrier layer 4 is lower than the polishing rate of the metal wiring layer 5, so that the copper in the wiring part is excessively polished while the barrier layer 4 is polished and removed, resulting in large dishing. 6 had occurred. In addition, since the polishing pressure applied to the barrier layer 4 and the insulating layer 2 below the high-density wiring portion is higher than that of the portion having a low wiring density, the degree of progress of polishing in the second polishing step is larger due to the wiring density. Different. As a result, the insulating layer 2 in the high-density wiring portion was excessively polished, and a large erosion 8 was generated. When dishing 6 or erosion 8 occurs, there is a problem that wiring resistance increases and electromigration easily occurs, and the reliability of the device is lowered.

The tantalum and tantalum compound used as the barrier layer 4 are difficult to chemically etch and have a higher hardness than copper, so that removal by mechanical polishing is not easy. If the hardness of the abrasive grains is increased in order to increase the polishing rate of the barrier layer 4, scratches are generated in the copper wiring having a lower hardness, and problems such as electrical defects are likely to occur. Further, when the concentration (content ratio) of abrasive grains in the abrasive is increased, it becomes difficult to maintain the dispersed state of the abrasive grains in the abrasive, resulting in problems such as sedimentation and gelation over time. Likely to happen.

Also, in CMP, it is necessary to prevent copper corrosion during polishing. Among the most effective and widely used corrosion inhibitors for copper and copper alloys, benzotriazole (hereinafter referred to as BTA) and its derivatives are known (for example, see Non-Patent Document 1). . BTA forms a dense film on the surface of copper and copper alloys, suppresses redox reactions to prevent etching, and is known to be effective as an additive for preventing dishing of copper wiring parts. (For example, refer to Patent Document 1). However, if only the amount of addition of BTA is increased, the copper polishing rate decreases and the polishing time becomes long, so that the defects of dishing 6 and erosion 8 may increase.

Furthermore, the use of a water-soluble polymer as a protective film forming agent for suppressing the dishing 6 of the metal wiring layer 5 has been studied. That is, the polishing rate ratio (metal layer / barrier layer) between the metal wiring layer 5 and the barrier layer 4 is large for the purpose of suppressing polishing of the barrier layer 4 and the insulating layer 2 while polishing and removing copper at high speed. An abrasive having a large polishing rate ratio (metal layer / insulating layer) between the metal wiring layer 5 and the insulating layer 2 has been developed (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 8-83780 (Claims) Japanese Patent Laid-Open No. 2001-144047 (Claims)

However, these abrasives all relate to the first polishing step for polishing and removing the metal wiring layer 5 such as the copper wiring layer, and in the second polishing step, the cap layer 3 is removed at a high speed, and An abrasive that satisfies the requirement to suppress the polishing of the insulating layer 2 made of a low dielectric constant material as much as possible has not yet been found.

Hereinafter, the problem in the second polishing step will be described in the case where the barrier layer 4 and the metal wiring layer 5 formed in this order on the insulating layer 2 are polished. Problems in the case of polishing one having the cap layer 3 on the insulating layer 2 will be described later.

In the layer configuration in which the barrier layer 4 and the metal wiring layer 5 are sequentially formed on the insulating layer 2, the barrier layer 4 is polished at a high speed in the second polishing step, and the metal wiring layer 5 is polished at an appropriate polishing rate. Furthermore, it is required to highly planarize the insulating layer 2 while cutting it.

That is, the polishing agent for the first polishing step is mainly required to polish the metal wiring layer 5 at a high polishing rate, whereas the polishing agent for the second polishing step has a high barrier layer 4. Polishing at a polishing rate and polishing the insulating layer 2 at a higher polishing rate than the metal wiring layer 5 are required, and the required characteristics of both are greatly different.

As described above, the role of the second polishing step in CMP is to completely remove the unnecessary barrier layer 4 portion and reduce dishing 6 generated in the first polishing step. In FIG. 1, when the size of the dishing 6 generated in the first polishing process is smaller than the film thickness of the barrier layer 4, the dishing 6 is removed by scraping only the barrier layer 4 in the second polishing process. It is also possible to eliminate the polishing of the metal wiring layer 5 and the insulating layer 2. However, the thickness of the barrier layer 4 is as thin as 20 to 40 nm, and the dishing 6 is suppressed to a range smaller than the thickness of the barrier layer 4 in order to polish and remove the metal wiring layer 5 at a high speed in the first polishing process. It is extremely difficult. Further, in the first polishing step, if there is local variation in the polishing rate of the metal wiring layer 5, over-polishing is required to completely remove unnecessary wiring metal residues in the surface. It becomes more difficult to keep 6 small.

Therefore, in the second polishing step, it is required to repair the dishing 6 larger than the film thickness of the barrier layer 4 generated in the first polishing step to realize high leveling.

More generally, as shown in FIG. 2, in a thin wiring or a high-density wiring, the insulating layer 2 in the wiring portion is excessively polished as compared with the insulating layer portion (Global portion) 9 having no wiring pattern. Although the layer 2 tends to be thin, in recent years, the reduction of the erosion 8 has become a major issue as the generation of semiconductors advances and the wiring portion becomes thinner.

When the cap layer 3 is provided, the following problems exist. In recent years, low dielectric constant materials have been used for the insulating layer 2 in order to reduce LSI wiring delay. However, since the low dielectric constant material is chemically and mechanically fragile, the barrier layer 4 is directly formed thereon. The barrier layer 4 is formed after the cap layer 3 made of, for example, silicon dioxide is formed on the insulating layer 2 made of a low dielectric constant material (hereinafter also referred to as a low dielectric constant insulating layer). Things have been done. However, while the relative dielectric constant of the low dielectric constant material constituting the insulating layer 2 is generally 3 or less, the relative dielectric constant of silicon dioxide formed by, for example, plasma CVD (chemical vapor deposition) is Since it is as high as 4, it is not preferable to leave the cap layer 3 at the time of planarization by polishing from the viewpoint of a low dielectric constant. That is, in the second polishing step, it is preferable to remove all the cap layer 3.

However, if the polishing time is increased to completely remove the cap layer 3, the polishing rate is greatly increased when the low dielectric constant insulating layer 2 that is more fragile than the cap layer 3 is exposed. There was a problem that the layer 2 was scraped more than necessary. If the low dielectric constant insulating layer 2 is cut too much, the metal wiring layer 5 must be further cut to flatten this portion. As a result, the excessive polishing amount of the metal wiring layer 5 becomes large and the resistance value is increased. The problem of increasing is caused. In order to avoid scraping of the low dielectric constant insulating layer 2 after the cap layer 3 is completely removed, the polishing rate of the low dielectric constant insulating layer 2 should be significantly suppressed relative to the polishing rate of the cap layer 3. is necessary. However, it has been difficult to suppress the polishing rate of the low dielectric constant insulating layer 2 chemically and mechanically more fragile than the polishing rate of the cap layer 3 with conventional polishing agents.

As an index indicating the ability to suppress the cutting of the low dielectric constant insulating layer 2 after the cap layer 3 is completely removed, the polishing rate of the low dielectric constant insulating layer 2 and the polishing rate of the silicon dioxide film as the cap layer 3 are (Hereinafter, referred to as a low dielectric constant insulating layer / silicon dioxide film selection ratio). The smaller the value of the selection ratio, the smaller the amount of cutting of the low dielectric constant insulating layer 2 after the cap layer 3 is completely removed. There is a need for an abrasive capable of minimizing the low dielectric constant insulating layer / silicon dioxide film selection ratio.

An object of the present invention is to provide an abrasive having excellent polishing performance suitable for planarization of embedded wiring in the manufacture of a semiconductor integrated circuit device. It is another object of the present invention to provide a polishing method having excellent polishing performance in a polishing process such as planarization of embedded wiring when manufacturing a semiconductor integrated circuit device.

A first aspect of the present invention is an abrasive for chemically and mechanically polishing a surface to be polished in the manufacture of a semiconductor integrated circuit device, comprising abrasive grains, an oxidizing agent, a protective film forming agent, an acid And an amine having a hydrocarbon group selected from an alkyl group having 6 to 20 carbon atoms, an aryl group, and an aryl-substituted alkyl group, and water.

The second aspect of the present invention is the abrasive according to the first aspect, wherein the amine having a hydrocarbon group is at least one selected from the group consisting of octylamine, dodecylamine and polyoxyethylene laurylamine. I will provide a.

A third aspect of the present invention is a method of supplying a polishing agent to a polishing pad, bringing a polishing target surface of a semiconductor integrated circuit device into contact with the polishing pad, and polishing by relative movement between the two, A polishing method is provided in which the abrasive is the abrasive according to the first aspect or the second aspect.

According to the present invention, it is possible to obtain an abrasive having excellent polishing performance suitable for planarization of embedded wiring in chemical mechanical polishing in the manufacture of a semiconductor integrated circuit device. Particularly in a laminated structure in which a cap layer made of a silicon dioxide film or the like is formed on a fragile low dielectric constant insulating layer, when the cap layer is completely removed to expose the low dielectric constant insulating layer, it is highly flat. A smooth surface. Moreover, according to the polishing method of the present invention, a semiconductor integrated circuit device having a highly flattened multilayer structure can be obtained.

1A to 1D are cross-sectional views of a semiconductor integrated circuit device schematically showing a polishing process at the time of forming a buried wiring by CMP. FIG. 2 is a cross-sectional view of a semiconductor integrated circuit device for explaining dishing and erosion that occur when a buried wiring is formed by CMP. FIG. 3 is a diagram showing an example of a polishing apparatus that can be used in the polishing method of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, tables, examples and the like. In addition, these figures, tables, examples, etc. illustrate the present invention, and do not limit the scope of the present invention. Other embodiments may belong to the category of the present invention as long as they meet the gist of the present invention.

The abrasive of the present invention is an abrasive for chemically and mechanically polishing a surface to be polished in the manufacture of a semiconductor integrated circuit device, and comprises abrasive grains, an oxidizing agent, a protective film forming agent, an acid, It contains an amine having a hydrocarbon group selected from an alkyl group having 6 to 20 carbon atoms, an aryl group, and an aryl-substituted alkyl group, and water. The abrasive according to the present invention has a slurry shape.

In the polishing of the surface to be polished in the manufacture of the semiconductor integrated circuit device, the flat surface of the insulating layer having the embedded metal wiring layer can be obtained by using the abrasive of the present invention. In addition, dishing and erosion can be suppressed by preferentially polishing the convex portion while suppressing preferential polishing of the concave portion.

Specifically, when a surface to be polished, in which a barrier layer and a metal wiring layer are sequentially formed on an insulating layer of a semiconductor integrated circuit device, is polished, the barrier layer is polished at a high polishing rate and the insulating layer (cap When the layer is present, the cap layer) can be polished at a higher polishing rate than the metal wiring layer. That is, the polishing performance suitable for the second polishing step described above can be exhibited. Furthermore, the polishing agent according to the present invention, when polishing the surface to be polished in which the cap layer, the barrier layer, and the metal wiring layer are formed in this order on the insulating layer, after removing the cap layer completely, The polished surface can be flattened while minimizing the amount of etching of the underlying insulating layer.

As described above, the polishing agent according to the present invention removes excess copper when polishing a surface to be polished in which a cap layer, a barrier layer, and a metal wiring layer are formed in this order on an insulating layer. It can use suitably for the 2nd grinding | polishing process used after a process.

Furthermore, in the polishing agent of the present invention, the above-mentioned effects can be obtained, and scratches on the metal wiring layer can be reduced, so that it is easy to form embedded metal wiring with high reliability and excellent electrical characteristics. It becomes. In addition, a high polishing rate can be realized, and the dispersion stability of the abrasive grains is also excellent.

In the present invention, the “surface to be polished” means an intermediate surface that appears in the process of manufacturing a semiconductor integrated circuit device. In the present invention, since one or more of the metal wiring layer, the barrier layer, the insulating layer, and the cap layer are objects to be polished, the “surface to be polished” according to the present invention includes a metal wiring layer, a barrier layer, and an insulating layer. And / or a cap layer will be present.

In addition, the “metal wiring layer” in the present invention means a layer made of planar metal wiring, but does not necessarily indicate only a layer spread over one surface as shown in FIG. Layers as a set of individual wirings are also included as in c) and (d). Further, it can be considered as a “metal wiring layer” including a portion such as a via for electrically connecting the planar metal wiring to another portion. Hereinafter, each component of the abrasive | polishing agent of this invention is explained in full detail.

The abrasive grains in the abrasive of the present invention can be appropriately selected from known abrasive grains. Specifically, particles made of at least one material selected from the group consisting of silica, alumina, cerium oxide (ceria), zirconium oxide (zirconia), titanium oxide (titania), tin oxide, zinc oxide and manganese oxide. Preferably there is. As silica, those produced by a known method can be used. For example, colloidal silica obtained by hydrolyzing silicon alkoxide such as ethyl silicate and methyl silicate by a sol-gel method can be used. Further, colloidal silica obtained by ion-exchange of sodium silicate and fumed silica obtained by vapor phase synthesis of silicon tetrachloride in an oxygen and hydrogen flame can be used.

Similarly, colloidal alumina can also be preferably used. Further, cerium oxide, zirconium oxide, titanium oxide, tin oxide, and zinc oxide produced by a liquid phase method or a gas phase method can also be preferably used. Among these, the use of colloidal silica is preferable because the particle size is easily controlled and a high-purity product can be obtained.

The average primary particle size of the abrasive grains needs to be in the range of 5 to 300 nm from the viewpoint of polishing characteristics and dispersion stability. It is preferably in the range of 5 to 60 nm, more preferably in the range of 10 to 60 nm. The average secondary particle size of the abrasive grains is preferably in the range of 8 to 300 nm.

As the abrasive grains, it is preferable to use those that are associated. The presence or absence of the association can be easily confirmed with an electron microscope. When the association ratio of the abrasive grains in the abrasive is particularly in the range of 1.5 to 5, the polishing rate of the insulating layer can be controlled without decreasing the polishing rate of the barrier layer. Here, the association ratio of the abrasive grains is defined as a value obtained by dividing the average secondary particle diameter of the abrasive grains in the abrasive slurry by the average primary particle diameter. The average primary particle size is determined as a particle size in terms of equivalent sphere from the specific surface area of the particles. The specific surface area of the particles is measured by a nitrogen adsorption method known as the BET method. The average secondary particle diameter is the diameter of the average aggregate in the abrasive and is measured using, for example, a particle size distribution meter using dynamic light scattering.

The content (concentration) of abrasive grains in the abrasive of the present invention is preferably in the range of 0.1 to 20% by mass with respect to the total mass of the abrasive, and the polishing rate and the polishing rate within the wafer surface It is preferable to set appropriately considering the uniformity and dispersion stability. A range of 1 to 15% by mass of the total mass of the abrasive is more preferable.

The oxidizing agent in the abrasive of the present invention forms an oxide film on the surface of the barrier layer. By removing this oxide film from the surface to be polished by mechanical force, polishing of the barrier layer is promoted. The oxidizing agent is at least selected from hydrogen peroxide, iodate, periodate, hypochlorite, perchlorate, persulfate, percarbonate, perborate and perphosphate. One is preferred. As iodate, periodate, hypochlorite, perchlorate, persulfate, percarbonate, perborate and perphosphate, ammonium salt, potassium salt, etc. are used. be able to. Of these, hydrogen peroxide is preferable because it does not contain an alkali metal component and does not produce harmful by-products.

In order to sufficiently obtain the effect of promoting polishing, the content (concentration) of the oxidizing agent in the abrasive of the present invention is preferably in the range of 0.01 to 50% by mass with respect to the total mass of the abrasive. Further, it is preferable to set appropriately considering the polishing rate and the like. A range of 0.2 to 10% by mass with respect to the total mass of the abrasive is more preferable, and a range of 0.2 to 2% by mass is particularly preferable.

The protective film forming agent in the abrasive of the present invention means a chemical having a function of forming a protective film on the surface of the metal wiring layer in order to prevent dishing of the metal wiring layer. For example, in the case where the metal wiring layer is made of copper or a copper alloy, any material may be used as long as it suppresses elution of copper by forming a film by physically or chemically adsorbing on the copper surface.

The protective film forming agent is preferably a compound represented by the following formula (1).

In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a carboxylic acid group.

Examples of the compound represented by the formula (1) include BTA, tolyltriazole (TTA) in which the H atom at the 4 or 5 position of the benzene ring of BTA is substituted with a methyl group, and benzotriazole-4 substituted with a carboxylic acid group -Carboxylic acid and the like. These may be used alone or in combination of two or more. The content (concentration) of the protective film forming agent in the abrasive of the present invention is preferably in the range of 0.001 to 5% by mass with respect to the total mass of the abrasive, from the viewpoint of polishing characteristics. A range of 01 to 1.0% by mass is more preferable, and a range of 0.05 to 0.5% by mass is particularly preferable.

The abrasive of the present invention contains an acid in addition to the above-described abrasive grains, oxidizing agent, and protective film forming agent. When the above-described oxidizing agent functions also as an acid, it is handled as an acid instead of an oxidizing agent.

As such an acid, it is preferable to use one or more inorganic acids selected from nitric acid, sulfuric acid and hydrochloric acid. Among these, it is preferable to use nitric acid which is an oxo acid having oxidizing power and does not contain halogen. The acid content (concentration) in the abrasive of the present invention is preferably in the range of 0.01 to 50% by mass, more preferably in the range of 0.01 to 20% by mass with respect to the total mass of the abrasive. A range of 0.02 to 0.5% by mass is particularly preferred. By adding an acid, the polishing rate of the barrier layer or the insulating layer can be increased. It is also possible to improve the dispersion stability of the abrasive.

In order to adjust the abrasive according to the present invention to a predetermined pH described later, a basic compound can be added together with the acid described above. As the basic compound, ammonia, potassium hydroxide, quaternary ammonium hydroxide such as tetramethylammonium hydroxide and tetraethylammonium hydroxide, monoethanolamine and the like can be used. Ammonia is preferred when it is preferable not to include an alkali metal.

In addition, you may add an acid and a basic compound in any step of preparation of the abrasive | polishing agent of this invention. For example, when using what was processed with the acid or the basic compound as a component of an abrasive | polishing agent, it corresponds to addition of the acid and basic compound which are demonstrated above. It can also be added after reacting all or part of the acid and basic compound used to form a salt. However, the polishing rate of the barrier layer can be increased, and the pH of the abrasive is in the desired range. In the present invention, it is preferable to add the acid and the basic compound separately from the viewpoint of easy adjustment and handling.

The content (concentration) of the basic compound in the abrasive is preferably in the range of 0.01 to 50% by mass, more preferably in the range of 0.01 to 10% by mass, based on the total mass of the abrasive. A range of 01 to 1% by mass is particularly preferred. In addition, the concentration of the acid and the basic compound in the abrasive when it becomes a salt means the concentration when it is assumed that the salt exists independently as an acid and a basic compound, respectively.

The pH of the abrasive according to the present invention is preferably in the range of 2-5. In consideration of the polishing characteristics and dispersion stability, the pH when silica is used as the abrasive is preferably 4 or less, and the pH is 2 to 4 depending on the desired polishing rate of the metal wiring layer (for example, copper wiring layer). Areas are used as appropriate.

When the abrasive grains are alumina or ceria, it is preferable to adjust to an optimum pH value in consideration of their isoelectric point and gelation region. For this purpose, a pH buffering agent may be used. The pH buffering agent can be used without particular limitation as long as it has pH buffering ability, but is selected from succinic acid, citric acid, oxalic acid, phthalic acid, tartaric acid and adipic acid which are polyvalent carboxylic acids. One or more are preferred. Moreover, glycylglycine and alkali carbonate can also be used. The content ratio (concentration) of the pH buffering agent in the abrasive is preferably 10% by mass or less with respect to the total mass of the abrasive. Note that the pH buffer is not treated as the acid or basic compound.

The amine having a hydrocarbon group selected from an alkyl group, an aryl group, and an aryl-substituted alkyl group having 6 to 20 carbon atoms in the polishing agent of the present invention can be obtained from silicon dioxide or the like without greatly scraping the low dielectric constant insulating layer. This is a component (hereinafter, referred to as a low dielectric constant layer polishing inhibiting component) that is blended in order to give selectivity to the polishing rate between the cap layer and the low dielectric constant insulating layer. In the polishing agent of the present invention, as such a low dielectric constant layer polishing suppressing component, an alkyl group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an H atom of the alkyl group are substituted with an aryl group. An amine having a hydrocarbon group selected from aryl-substituted alkyl groups having 6 to 20 carbon atoms is used. Specifically, octylamine, dodecylamine, and polyoxyethylene laurylamine are exemplified, and it is preferable to use at least one selected from the group consisting of these amines. Such an amine does not deteriorate the dispersibility of the abrasive slurry. In the present specification, the amine includes not only a primary amine having a primary amino group but also a secondary amine having a secondary amino group and a tertiary amine having a tertiary amino group.

The amine functions to suppress polishing of the low dielectric constant insulating layer because of the amino group (primary amino group, secondary amino group or tertiary amino group) which is a hydrophilic group of these compounds, and hydrophobicity. This is considered to be the action of the hydrocarbon group (alkyl group having 6 to 20 carbon atoms, aryl group, aryl-substituted alkyl group). That is, the amine having a hydrophilic group and a hydrophobic group is interposed between an abrasive grain made of an oxide and a hydrophilic low-dielectric constant insulating layer having an organic group and a hydrophobic surface. This is thought to be due to the interaction. Even if the amine has a hydrophilic group and a hydrophobic group, if the hydrophobic group has less than 6 carbon atoms, a sufficient effect of suppressing polishing of the low dielectric constant insulating layer does not occur. In addition, even when the hydrocarbon group has 6 to 20 carbon atoms and does not have a primary to tertiary amino group (for example, polyoxyethylene alkyl ether), a low dielectric constant Polishing of the insulating layer is suppressed, and the low dielectric constant insulating layer / silicon dioxide film selection ratio cannot be reduced. Moreover, since the characteristic regarding stability will arise, such as the dispersibility of an abrasive | polishing agent falling, it is not preferable.

In Japanese Patent Application Laid-Open No. 2007-12679, the polishing rate between the cap layer and the low dielectric constant insulating layer is selected, and the low dielectric constant insulating layer is exposed after the cap layer has been scraped. An abrasive having the property that the polishing rate is significantly reduced is disclosed. However, the dielectric constant k of the low dielectric constant insulating layer described in this publication is 2.7, and the use of an insulating layer having a lower dielectric constant (relative dielectric constant of 2.2) that has been increasingly demanded for use in recent years. It was difficult to apply to polishing.

According to the polishing agent of the present invention containing the low dielectric constant layer polishing inhibiting component, the value of the selective ratio between the low dielectric constant insulating layer having a relative dielectric constant k of 2.2 and the cap layer made of silicon dioxide is sufficiently high. Can be small. Specifically, the low dielectric constant insulating layer / silicon dioxide film selection ratio can be made 1.0 or less by the abrasive of the present invention. More preferably, it is 0.5 or less.

As described above, the polishing agent according to the present invention is selected for the polishing rate of the cap layer and the low dielectric constant insulating layer even for an insulating layer having a low dielectric constant (for example, relative dielectric constant k = 2.2). The cap layer and the metal wiring layer are included because the polishing rate is greatly reduced at the stage where the low dielectric constant insulating layer is exposed after the cap layer has been scraped off. When polishing the surface to be polished, after completely removing the cap layer, it is possible to flatten the surface to be polished while minimizing the amount of cutting of the underlying low dielectric constant insulating layer It has excellent characteristics. Such characteristics are considered to be obtained by combining chemical polishing resulting from the chemical composition of the polishing agent and mechanical polishing caused by the abrasive grains in CMP technology, and could not be realized with conventional polishing agents. It is an effect.

The content (concentration) of the low dielectric constant layer polishing inhibiting component in the abrasive is sufficient to reduce the low dielectric constant insulating layer / silicon dioxide film selection ratio, so that the total mass of the abrasive is obtained. The content is preferably in the range of 0.01 to 1% by mass, and preferably set appropriately in consideration of the desired selection ratio. A range of 0.02 to 0.5% by mass with respect to the total mass of the abrasive is more preferable, and a range of 0.04 to 0.2% by mass is even more preferable.

In the abrasive according to the present invention, water is used to stably disperse the abrasive grains. Any water may be used as long as it does not violate the gist of the present invention, but it is preferable to use pure water, ion-exchanged water or the like. Water is preferably contained in the range of 40 to 98% by mass with respect to the total mass of the abrasive.

Further, the abrasive of the present invention includes a primary alcohol having 1 to 4 carbon atoms, a glycol having 2 to 4 carbon atoms, and CH ₃ CH (OH) CH in order to adjust fluidity, dispersion stability, and polishing rate. ₂ O—C _m H _2m-1 ether (where m is an integer of 1 to 4), N-methyl-2-pyrrolidone, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone and carbonic acid It is preferable to add at least one organic solvent selected from the group consisting of propylene. Specifically, the primary alcohol is preferably methyl alcohol, ethyl alcohol, or isopropyl alcohol. As glycol, ethylene glycol and propylene glycol are preferable. As the ether, propylene glycol monomethyl ether and propylene glycol monoethyl ether are preferable. N-methyl-2-pyrrolidone, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and propylene carbonate are polar solvents having a relative dielectric constant in the range of 30 to 65 at 25 ° C. Can be dissolved at a high concentration.

Since the abrasive according to the present invention contains water having a high surface tension, the addition of the organic solvent is effective for adjusting the fluidity. In particular, the organic solvent acts as a good solvent for the compound represented by the formula (1), which is a protective film forming agent, so the content ratio (concentration) of the protective film forming agent in the abrasive is within a desired range. There is an advantage that it is easy to adjust.

The abrasive according to the present invention requires a surfactant, a chelating agent, a reducing agent, a viscosity imparting agent or a viscosity modifier, an anti-aggregating agent or a dispersing agent, a rust preventive agent, etc., unless it is contrary to the spirit of the present invention. Depending on the content, it can be appropriately contained. However, when these additives have the functions of an oxidizing agent, a protective film forming agent, an acid or a basic compound, they are handled as an oxidizing agent, a protective film forming agent, an acid or a basic compound.

In the abrasive according to the present invention, the above-described constituent components are contained in the predetermined content ratio (concentration), the abrasive grains are uniformly dispersed, and other components are uniformly dissolved. Prepared and used. For mixing, a stirring and mixing method usually used in the production of an abrasive, for example, a stirring and mixing method using an ultrasonic disperser, a homogenizer, or the like can be employed. The abrasive according to the present invention does not necessarily have to be supplied to the polishing site as a mixture of all the pre-configured abrasive materials. When supplying to the place of polishing, the polishing material may be mixed to form the composition of the abrasive.

Since the polishing agent according to the present invention can also control the polishing rate of a metal wiring layer made of, for example, copper, it is suitable for obtaining a flat surface of an insulating layer having an embedded metal wiring layer in the manufacture of a semiconductor integrated circuit device. It is. In particular, it is suitable for polishing a surface to be polished formed by laminating a barrier layer and a metal wiring layer on an insulating layer. That is, the abrasive according to the present invention has both functions of high-speed polishing of the barrier layer and flattening of the insulating layer having the embedded metal wiring layer.

Particularly, a high effect can be obtained when the barrier layer is a layer made of at least one material selected from the group consisting of tantalum, a tantalum alloy and a tantalum compound. However, it can also be applied to films made of other metals, etc., and even when a layer made of a metal or a metal compound other than tantalum, such as Ti, TiN, TiSiN, WN, etc., is used as the barrier layer. Effects can be obtained.

Any known material may be used as the material constituting the insulating layer that is one of the objects to be polished by the abrasive according to the present invention. For example, a silicon dioxide film can be exemplified. As the silicon dioxide film, one having a crosslinked structure of Si and O and having a ratio of the number of atoms of Si and O of 1: 2 is generally used, but other films may be used. As such a silicon dioxide film, a film deposited by plasma CVD using tetraethoxysilane (TEOS) or silane gas (SiH ₄ ) is generally known.

In recent years, a film made of a low dielectric constant material having a relative dielectric constant of 3 or less has been used as an insulating layer for the purpose of suppressing signal delay. As such a low dielectric constant material film, a porous silica film or an organic silicon material (generally referred to as SiOC) film mainly composed of Si—O bonds and containing CH ₃ bonds is known. These films can also be suitably used as an insulating layer to which the abrasive according to the present invention is applied.

The above-mentioned organosilicon material is an extension of the conventional technology as a process technology, and mass production technology with a wide range of application has been achieved by performing appropriate process tuning. Therefore, there is a demand for a technique for flattening a film using this low dielectric constant material, and the abrasive according to the present invention can be suitably used for that purpose.

Examples of the organic silicon material that is a low dielectric constant material include trade name Black Diamond 1 (relative permittivity 2.7, Applied Materials technology), trade name Coral (relative permittivity 2.7, Novellus Systems technology), Aurora 2. 7 (relative permittivity: 2.7, Japan ASM Co., Ltd.), and the like. Among them, a compound having a Si—CH ₃ bond is preferably used. As an organic silicon material whose dielectric constant is further reduced than that of the above-mentioned material, a trade name Black Diamond 2x (relative dielectric constant 2.2, Applied Materials, Inc. technology) is known.

The abrasive according to the present invention can also be suitably used for a structure in which a cap layer is formed on an insulating layer. For example, in a multilayer structure in which a cap layer, a barrier layer, and a metal wiring layer are sequentially laminated on a low dielectric constant insulating layer, after the cap layer is completely removed, the low dielectric constant insulating layer is flattened without much shaving. Suitable for. The selection ratio of the low dielectric constant insulating layer / cap layer, specifically, the selection ratio of SiOC layer / silicon dioxide layer can be 1.0 or less. The selection ratio of SiOC layer / silicon dioxide layer is preferably in the range of 0.04 to 0.50, and more preferably in the range of 0.05 to 0.30.

The cap layer is a groove for embedding a metal wiring layer in a chemically and mechanically fragile low dielectric constant insulating layer when the low dielectric constant material is used for the insulating layer to improve the adhesion between the insulating layer and the barrier layer. Is provided for use as a mask material when formed by etching. In addition, the cap layer is provided for the purpose of preventing deterioration of the low dielectric constant material.

As the cap layer, a film having silicon and oxygen as constituent elements is generally used. An example of such a film is a silicon dioxide film. As the silicon dioxide film, a film having a crosslinked structure of Si and O and having a ratio of the number of atoms of Si and O of 1: 2 is generally used, but other films may be used. As such a silicon dioxide film, a film deposited by plasma CVD using tetraethoxysilane (TEOS) or silane gas (SiH ₄ ) is known.

The abrasive according to the present invention uses a silicon dioxide film in which TEOS is deposited by CVD as a cap layer, and a trade name Black Diamond 1 (relative dielectric) which is a compound having a Si—CH ₃ bond as a low dielectric constant organosilicon material. In the case of using the rate 2.7), it can be particularly preferably used. Furthermore, it can be used suitably also when using the product name Black Diamond 2x (relative permittivity 2.2) having a low relative permittivity.

The metal wiring layer to be polished by the abrasive according to the present invention is preferably a layer made of one or more materials selected from copper, copper alloys and copper compounds. However, the abrasive of the present invention can also be applied to metals other than copper, such as metal films such as Al, W, Ag, Pt, and Au.

As a method for polishing a surface to be polished of a semiconductor integrated circuit device using the polishing agent of the present invention, the polishing surface of the semiconductor integrated circuit device is brought into contact with the polishing pad while supplying the polishing agent to the polishing pad. A method of polishing by relative motion between the two is preferable.

In the above polishing method, a conventionally known polishing apparatus can be used as the polishing apparatus. FIG. 3 is a diagram showing an example of a polishing apparatus that can be used in the polishing method of the present invention. The polishing apparatus 20 supplies a polishing head 22 for holding 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 an abrasive 25 to the polishing pad 24. A polishing agent supply pipe 26 is provided. While supplying the polishing agent 25 from the polishing agent 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 relative to each other. It is comprised so that it may grind | polish by rotating. Note that the polishing apparatus used in the embodiment of the present invention is not limited to such a structure.

The polishing head 22 may perform a linear motion as well as a rotational motion. Further, the polishing surface plate 23 and the polishing pad 24 may be as large as or smaller than the semiconductor integrated circuit device 21. In that case, it is preferable that the entire surface to be polished of the semiconductor integrated circuit device 21 can be polished by relatively moving the polishing head 22 and the polishing surface plate 23. Furthermore, the polishing surface plate 23 and the polishing pad 24 do not have to perform rotational movement, and may move in one direction, for example, by a belt type.

The polishing conditions of the polishing apparatus 20 are not particularly limited, but by applying a load to the polishing head 22 and pressing it against the polishing pad 24, it is possible to increase the polishing pressure and improve the polishing rate. The polishing pressure is preferably about 0.5 to 50 kPa, and more preferably about 3 to 40 kPa from the viewpoint of preventing polishing defects such as uniformity of the polished surface of the semiconductor integrated circuit device 21 at the polishing rate, flatness, and scratches. The number of rotations of the polishing surface plate 23 and the polishing head 22 is preferably about 50 to 500 rpm, but is not limited thereto. The supply amount of the abrasive 25 is appropriately adjusted and selected depending on the material constituting the surface to be polished, the composition of the abrasive, each of the above polishing conditions, etc. For example, when polishing a wafer having a diameter of 200 mm, it is generally 100. A supply rate of about ~ 300 ml / min is preferred.

The polishing pad 24 may be made of a general nonwoven fabric, foamed polyurethane, porous resin, non-porous resin, or the like. Further, in order to promote the supply of the polishing agent 25 to the polishing pad 24 or to collect a certain amount of the polishing agent 25 on the polishing pad 24, the surface of the polishing pad 24 has a lattice shape, a concentric circle shape, a spiral shape, or the like. Groove processing may be performed.

In addition, if necessary, the pad conditioner may be brought into contact with the surface of the polishing pad 24 and polishing may be performed while conditioning the surface of the polishing pad 24.

In the polishing method according to the present invention using such a polishing apparatus, a groove such as a wiring pattern or a recess such as a via is formed in an insulating layer on a substrate, and then a barrier layer is formed. A method of forming a buried metal wiring layer by removing the metal layer and the barrier layer by CMP until the surface of the insulating layer other than the concave portion is exposed on the surface to be polished formed by sputtering or plating for embedding in Is preferably used.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

(1) Preparation of abrasive (1-1) Each of the abrasives of Examples 1 to 11 was prepared as shown below. Specifically, nitric acid and a pH buffering agent shown in Table 1 were added to water, and amines E1 to E3, which are low dielectric constant layer polishing inhibiting components, were added and stirred for 10 minutes to obtain solution a. Moreover, BTA which is a protective film forming agent was dissolved in ethylene glycol (EG) which is a good solvent to obtain a liquid b having a solid content concentration of 40% by mass of the protective film forming agent. In Table 1, amine E1 represents polyoxyethylene laurylamine, E2 represents octylamine, and E3 represents dodecylamine.

Next, the liquid b was added to the liquid a, and then colloidal silica in which silica was dispersed in water was gradually added, and then the basic compound KOH was gradually added to adjust the pH. Thereafter, an aqueous solution of hydrogen peroxide as an oxidizing agent was further added and stirred for 30 minutes to obtain an abrasive. Table 1 shows the content (concentration: mass%) of each component, pH buffer, basic compound, and ethylene glycol (EG) used in each example with respect to the entire abrasive. Pure water was used as water.

(1-2) Each abrasive of Comparative Examples 1 to 3 was prepared as shown below. That is, nitric acid and a pH buffer were added to water, and E4 to E6 were added instead of amines E1 to E3, followed by stirring for 10 minutes to obtain solution a. Moreover, BTA which is a protective film forming agent was dissolved in EG which is a good solvent to obtain a liquid b having a BTA solid content concentration of 40% by mass. E4 used in Comparative Example 1 represents butylethanolamine, E5 used in Comparative Example 2 represents butyldiethanolamine, and E6 used in Comparative Example 3 represents polyoxyethylene lauryl ether.

Next, the liquid b was added to the liquid a, then colloidal silica was gradually added, and further KOH was gradually added to adjust the pH. Thereafter, an aqueous solution of hydrogen peroxide as an oxidizing agent was further added and stirred for 30 minutes to obtain an abrasive. Table 1 shows the content (concentration: mass%) of each component, pH buffer, basic compound, and EG used in Comparative Examples 1 to 3 with respect to the entire abrasive. Pure water was used as water.

(1-3) Each abrasive of Comparative Examples 4 to 6 was prepared as shown below. That is, nitric acid and a pH buffer were added to water and stirred to obtain a solution a. Moreover, BTA was melt | dissolved in EG which is the good solvent, and b liquid whose solid content concentration of BTA is 40 mass% was obtained.

Next, the liquid b was added to the liquid a, then colloidal silica was gradually added, and further KOH was gradually added to adjust the pH. Thereafter, an aqueous solution of hydrogen peroxide was further added and stirred for 30 minutes to obtain an abrasive. Table 1 shows the content (concentration: mass%) of each component, pH buffer, basic compound, and EG used in Comparative Examples 4 to 6 with respect to the entire abrasive. Pure water was used as water.

(2) Measurement of pH The pH of the abrasive slurry prepared in Examples 1 to 11 and Comparative Examples 1 to 6 was measured at 25 ° C. using pH 81-11 manufactured by Yokogawa Electric Corporation. The measurement results are shown in Table 1.

(3) Measurement of average primary particle size, average secondary particle size, and association ratio of abrasive grains The average primary particle size of abrasive grains is determined from the specific surface area of particles obtained by drying an aqueous dispersion, and the equivalent spherical equivalent particle size As sought. The specific surface area of the particles was measured by a BET single-point method, which is a nitrogen adsorption method, using Flowsob II2300 (manufactured by Shimadzu Corporation). The average secondary particle size of the abrasive was measured with Microtrac UPA (Nikkiso Co., Ltd.). The association ratio (average secondary particle size / average primary particle size) was determined. The results were as follows. The abrasive grains of Examples 1 to 11 and Comparative Examples 1 to 4 had an average primary particle size of 29 nm, an average secondary particle size of 61 nm, and an association ratio of 2.1. The abrasive grains of Comparative Example 5 had an average primary particle size of 17 nm, an average secondary particle size of 23 nm, and an association ratio of 1.4. The abrasive grains of Comparative Example 6 had an average primary particle size of 35 nm, an average secondary particle size of 50 nm, and an association ratio of 1.4.

(4) Evaluation of polishing characteristics of abrasives The polishing performance of the abrasives obtained in Examples 1 to 11 and Comparative Examples 1 to 6 was evaluated by the following method.

(4-1) Polishing conditions Polishing was performed using the following apparatus under the following conditions.
Polishing machine: Fully automatic CMP machine MIRRA (manufactured by APPLIED MATERIALS)
(Wafer size 200mm diameter)
Small polishing machine: Nanofactor (manufactured by Nano Factor)
(When wafer size is 45mm square)
Polishing pressure: 14kPa
Platen (plate) rotation speed: shown in Table 2.
Head (substrate holding part) rotation speed: 80 rpm
Abrasive supply rate: 200 ml / min Polishing pad: Hard pad, IC1400 (Rohm and Haas)
Soft pad is H7000 (Fujibow)

(4-2) Object to be polished The following blanket wafers (a) to (d) were used as objects to be polished. The wafer size was 200 mm for Examples 4 to 6 and Comparative Examples 5 and 6. Other than that, the 45 mm square thing obtained by cutting a 200 mm diameter wafer was used.

(A) Metal wiring layer polishing rate evaluation wafer A wafer in which a Cu layer having a thickness of 1500 nm was formed on a substrate by plating was used.
(B) Wafer for barrier layer polishing rate evaluation A wafer in which a tantalum (Ta) layer having a thickness of 200 nm was formed on a substrate by a sputtering method was used.
(C) Cap layer polishing rate evaluation wafer A wafer in which a silicon dioxide (SiO ₂ ) layer having a thickness of 800 nm was formed on a substrate by plasma CVD was used.
(D) Wafer for low dielectric constant insulating layer polishing rate evaluation A wafer in which a SiOC (A) layer having a thickness of 800 nm was formed by plasma CVD using Black Diamond 1 (relative dielectric constant 2.7) on a substrate was used. . In addition, a wafer was used in which a SiOC (B) layer having a thickness of 800 nm was formed on the substrate by plasma CVD using Black Diamond 2x (relative dielectric constant 2.2).

(4-3) Method for evaluating characteristics of polishing agent The polishing rate was calculated from the film thickness before and after polishing. For the measurement of the film thickness, the metal wiring layer (Cu layer) and the barrier layer (Ta layer) were measured using a sheet resistance measuring device RS75 (manufactured by KLA Tencor) calculated from the surface resistance by the four-probe method. For the rate insulating layer (SiOC (A) layer, SiOC (B) layer) and cap layer (SiO ₂ layer), an optical interference type fully automatic film thickness measuring device UV1280SE (manufactured by KLA Tencor) was used.

(4-4) Evaluation of Blanket Wafer Polishing Characteristics Using the above blanket wafers, the polishing rates of the metal wiring layer, barrier layer, cap layer and low dielectric constant insulating layer were measured and evaluated. Cu layers, Ta layers, SiO ₂ layers, SiOC (A) layers, and SiOC (B) layers obtained by using the abrasives of Examples 1 to 11 and Comparative Examples 1 to 6 and using the blanket wafer. Table 2 shows each polishing rate (unit: nm / min). Table 2 shows the selection ratio of SiOC (A) layer / SiO ₂ layer and the selection ratio of SiOC (B) layer / SiO ₂ layer.

From the results shown in Table 2, when the abrasives obtained in Examples 1 to 11 were used, the polishing rate of the SiO ₂ layer as the cap layer was large, and the SiOC (A) layer and the SiOC as the low dielectric constant insulating layer. (B) The polishing rate of the layer is relatively small, and the selection ratio of SiOC (A) layer / SiO ₂ layer and SiOC (B) layer / SiO ₂ layer is extremely small, 0.5 or less. I understand. Therefore, it is understood that by using such an abrasive, after the cap layer is polished and removed, an abrasive that is particularly suitable for carrying out the polishing without significantly shaving the low dielectric constant insulating layer can be obtained. The

On the other hand, in the abrasives of Comparative Example 1 and Comparative Example 2, an amine having an alkyl group having less than 6 carbon atoms is blended in place of the specific amine which is a low dielectric constant layer polishing suppressing component. Moreover, the effect of suppressing the polishing rate of the SiOC (B) layer having a low dielectric constant among the low dielectric constant insulating layers is not sufficient. Therefore, the selection ratio of SiOC (B) layer / SiO ₂ layer is a value exceeding 1.0.

In the polishing agent of Comparative Example 3, an ether compound having no amino group is blended in place of the specific amine which is a low dielectric constant layer polishing inhibiting component, so that the dielectric constant is particularly low among the low dielectric constant insulating layers. The effect of suppressing the polishing rate of the SiOC (B) layer is not sufficient. Therefore, the desired selectivity (1.0 or less) of SiOC (B) layer / SiO ₂ layer cannot be realized.

Since the abrasive | polishing agent of the comparative example 4 does not contain a low dielectric constant layer grinding | polishing suppression component, the effect which suppresses the grinding | polishing speed | rate of the SiOC (B) layer which is a low dielectric constant insulating layer is not enough. Therefore, the desired selectivity (1.0 or less) of SiOC (B) layer / SiO ₂ layer cannot be realized.

Furthermore, the abrasives of Comparative Example 5 and Comparative Example 6 do not contain a low dielectric constant layer polishing inhibiting component, and further, the pH of the abrasive slurry and the association ratio of the abrasive grains are out of the preferred ranges. The effect of suppressing the polishing rate of the SiOC (A) layer, which is an insulating layer, is not sufficient. As a result, a desired SiOC (A) layer / SiO ₂ layer selection ratio (1.0 or less) is not obtained.

Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application 2010-128116 filed on June 3, 2010, the contents of which are incorporated herein by reference.

According to the present invention, it is possible to provide a polishing agent for chemical mechanical polishing that is used for planarization of embedded wiring in the manufacture of a semiconductor integrated circuit device, having excellent polishing performance and good storage stability.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Insulating layer, 3 ... Cap layer, 4 ... Barrier layer, 5 ... Metal wiring layer, 6 ... Dishing, 7 ... Embedded wiring, 8 ... Erosion, 9 ... Global part, 20 ... Polishing apparatus, 21 ... Semiconductor integrated circuit device 22... Polishing head 23. Polishing surface plate 24. Polishing pad 25. Polishing agent 26.

Claims

An abrasive for chemically and mechanically polishing a surface to be polished in the manufacture of a semiconductor integrated circuit device,
Abrasive grains,
An oxidizing agent,
A protective film forming agent;
Acid,
An amine having a hydrocarbon group of 6 to 20 carbon atoms selected from an alkyl group, an aryl group and an aryl-substituted alkyl group;
An abrasive containing water.
The abrasive according to claim 1, wherein the amine having a hydrocarbon group is at least one selected from the group consisting of octylamine, dodecylamine and polyoxyethylene laurylamine.
The protective film forming agent is a compound represented by the formula (1) (wherein R 1 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a carboxylic acid group). The abrasive | polishing agent of Claim 1 or 2 which is.
The abrasive grain according to any one of claims 1 to 3, wherein the abrasive grains are particles made of at least one material selected from the group consisting of silica, alumina, cerium oxide, zirconium oxide, titanium oxide, tin oxide, zinc oxide and manganese oxide. The abrasive | polishing agent of Claim 1.
The abrasive according to claim 4, wherein the abrasive grains are made of colloidal silica.
0.1 to 20% by mass of the abrasive grains, 0.01 to 50% by mass of the oxidizing agent, 0.001 to 5% by mass of the protective film forming agent, and 0.001 to 5% by mass of the abrasive based on the total mass of the abrasive. 6. The composition according to claim 1, wherein 0.01 to 50% by mass, 0.01 to 1.0% by mass of the amine, and 40 to 98% by mass of the water are contained. Abrasive.
The abrasive according to any one of claims 1 to 6, wherein the pH is in the range of 2 to 5.
The abrasive according to any one of claims 1 to 7, further comprising a pH buffer.
The abrasive according to any one of claims 1 to 8, which is an abrasive for polishing a surface to be polished in which a barrier layer and a metal wiring layer are sequentially formed on an insulating layer.
A polishing agent for polishing a surface to be polished in which a cap layer, a barrier layer, and a metal wiring layer are sequentially formed on an insulating layer made of a low dielectric constant material having a relative dielectric constant of 3 or less. 10. The abrasive | polishing agent of any one of 9.
The abrasive according to claim 9 or 10, wherein the metal wiring layer is made of copper, and the barrier layer is made of at least one selected from the group consisting of tantalum, a tantalum alloy and a tantalum compound.
A polishing method for supplying a polishing agent to a polishing pad, bringing a polishing target surface of a semiconductor integrated circuit device into contact with the polishing pad, and polishing by relative movement between the two, wherein the polishing agent is the polishing agent. A polishing method, which is the abrasive according to any one of the above.
13. The polishing according to claim 12, wherein in the manufacture of a semiconductor integrated circuit device having a metal wiring layer embedded in an insulating layer, the polishing agent is used in a polishing step after the metal wiring layer is polished and a barrier layer appears. Method.