JP2013065858A - Aqueous dispersing element for chemical mechanical polishing, chemical mechanical polishing method, and kit for preparing aqueous dispersing element for chemical mechanical polishing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous dispersion element for chemical mechanical polishing, chemical mechanical polishing method, and kit for preparing the aqueous dispersion element for chemical mechanical polishing, capable of achieving a highly precise polished surface without generating surface defects, such as material peeling or scratch, on the polished surface, and without changing physical properties of an isolation layer in applying chemical mechanical polishing to the isolation layer.SOLUTION: The aqueous dispersion element for chemical mechanical polishing contains: (A) abrasive grain, (B) quinolinecarboxylic acid and/or pyridinecarboxylic acid, (C) aliphatic organic acid with carbon number of 4 or higher, (D) oxidizer, (E) nonionic surfactant with triple linkage, and (F) dispersion medium. The (A) abrasive grain is colloidal silica with an average primary grain diameter of 5-55 nm and a degree of association of 1.9-4.0.

Description

  The present invention relates to a chemical mechanical polishing aqueous dispersion, a chemical mechanical polishing method, and a kit for preparing the chemical mechanical polishing aqueous dispersion. More specifically, it can be used in a process of forming a copper wiring formed in an interlayer insulating layer having a two-layer structure of a low dielectric constant insulating layer / high dielectric constant insulating layer of a semiconductor device. Chemical mechanical polishing aqueous dispersion capable of effectively chemically mechanically polishing a material to be polished and capable of obtaining a sufficiently flat and highly accurate finished surface, and a chemical mechanical polishing method using the same And a kit for preparing the chemical mechanical polishing aqueous dispersion.

  In recent years, with the increase in the density of semiconductor devices, the miniaturization of wirings formed in the semiconductor devices has progressed. As a technique that can achieve further miniaturization of the wiring, a technique called a damascene method is known. This method forms a desired wiring by embedding a wiring material in a groove or the like formed in an insulating layer and then using chemical mechanical polishing to remove excess wiring material deposited other than the groove. It is. Here, when using copper or copper alloy as the wiring material, in order to avoid migration of copper atoms into the insulator, usually tantalum, tantalum nitride, titanium nitride, etc. are used at the interface between the copper or copper alloy and the insulator. A high-strength, high-dielectric-constant insulating layer (conductive barrier layer) is formed as a material.

  When the damascene method is employed in the manufacture of a semiconductor device using copper or a copper alloy as a wiring material, there are various chemical mechanical polishing methods, and a first polishing step for mainly removing copper or a copper alloy and a mainly conductive method. A two-stage chemical mechanical polishing comprising a second polishing step for removing the conductive barrier layer is preferably performed. This second polishing step not only removes the conductive barrier layer but also polishes the interlayer insulating layer existing under the conductive barrier layer at the same time. Can be obtained.

  In addition, as the miniaturization progresses further, the copper wiring width becomes very narrow, and sufficient electrical characteristics cannot be obtained only by using a low resistance copper wiring, and the dielectric constant is low as an interlayer insulating layer. A wiring structure using a low dielectric constant material (Low-k material) has been applied. In particular, by using a low dielectric constant material having a relative dielectric constant (k) of less than 2.5, it is possible to reduce the electric capacity applied to the interlayer insulating layer between the copper wirings. Electrical characteristics can be maximized. In addition, when a layer is formed using a low dielectric constant material, a large number of holes can be created in the material. Therefore, by adjusting the ratio and size of the holes, the relative dielectric constant of the layer can be adjusted. Can do.

  If the percentage of holes is large, the relative dielectric constant of the layer can be made very low, but the mechanical strength of the material tends to be very weak, so that the resulting layer is subjected to chemical mechanical polishing. There is a possibility that the strength that can withstand the stress applied to the substrate cannot be maintained.

  In addition, since the above-described low dielectric constant insulating layer having holes has a large ratio of holes, the film is easily damaged by chemical mechanical polishing. When such damage occurs in the low-k film, the electrical characteristics of the low dielectric constant insulating layer such as an increase in the dielectric constant and an increase in leakage current after the manufacturing process such as etching, ashing, or wet cleaning are obtained. It may get worse. Such deterioration of electrical characteristics results in deterioration of the reliability of the semiconductor device, which is not preferable.

  As in the above-described technique, when using a hard silicon dioxide film having a high relative dielectric constant and an interlayer insulating layer in the second polishing step, surface defects are not generated on the surface to be polished, and relatively high accuracy is achieved. Flattening is possible.

  However, when a low dielectric constant insulating layer having a low mechanical strength is used, (i) peeling or surface defects called scratches are generated on the surface to be polished by chemical mechanical polishing, and (ii) a fine wiring structure. The polishing rate of the low dielectric constant insulating layer, which is the material to be polished, is remarkably increased when polishing a wafer having the following characteristics: (iii) a barrier layer and For reasons such as poor adhesion to the low dielectric constant insulating layer, an insulating layer called a cap layer made of silicon dioxide or the like having a higher dielectric constant than that of the low dielectric constant insulating layer is formed above the low dielectric constant insulating layer. And forming a two-layer interlayer insulating layer of (lower layer) low dielectric constant insulating layer / (upper layer) high dielectric constant insulating layer (insulating layer having a relative dielectric constant higher than that of the low dielectric constant insulating layer) Is used.

  When chemical mechanical polishing is performed, it is necessary to quickly remove the high dielectric constant insulating layer as an upper layer and suppress the polishing rate of the lower low dielectric constant insulating layer as much as possible. That is, the polishing rate (RR2) of the high dielectric constant insulating layer and the polishing rate (RR1) of the low dielectric constant insulating layer are required to have a relationship of RR2> RR1.

  When polishing a low dielectric constant insulating layer, not only the polishing rate is suppressed, but also the physical properties (specific dielectric constant, leakage current value, etc.) of the surface to be polished must not be changed. As the miniaturization progresses, it is necessary to further reduce the relative dielectric constant of the low dielectric constant insulating layer, and accordingly, the hole diameter of the material must be increased. As the pore size of the low dielectric constant insulating layer increases, not only does the low dielectric constant insulating layer become brittle, but the physical properties of the low dielectric constant insulating layer may change due to chemical mechanical polishing. A technique for suppressing the polishing rate without changing the thickness is required.

  Thus, since the second polishing step corresponds to a so-called finishing step, in the second polishing step, it is possible to suppress material peeling and surface defects on the fragile surface to be polished, and to physically treat the surface to be polished. A chemical mechanical polishing aqueous dispersion capable of suppressing the polishing rate without changing the properties is required.

  The second polishing step is mainly intended to remove the high dielectric constant insulating layer. From the viewpoint of shortening the polishing process time, it is necessary to have a high polishing rate for the surface to be polished. If it is increased, material peeling or surface defects will occur on the brittle polished surface. In addition, as described above, when a hard cap layer is formed on the low dielectric constant insulating layer, it is necessary to have a high polishing rate for the silicon dioxide film. Therefore, in order to obtain a highly polished surface, it is necessary to polish a high dielectric constant insulating layer at a low polishing pressure, and a high polishing rate for a high dielectric constant insulating layer and silicon dioxide film even under a low polishing pressure. Is required.

  As a specific example, Patent Document 1 discloses a polishing composition for an alkaline region containing abrasive grains made of silicon oxide, an oxidizing agent, and carbonate. When this polishing liquid is used, the polishing rate of the high dielectric constant insulating layer can be sufficiently obtained, but the polishing rate of the low dielectric constant insulating layer cannot be sufficiently suppressed. If formed, a sufficient polishing rate cannot be obtained for the silicon dioxide film, and the polishing process time becomes long, leading to a reduction in throughput.

Further, Patent Document 2 discloses a polishing composition containing a specific polyether-modified silicone and various additives. By using this polishing liquid, low dielectric constant insulation is achieved by the effect of the polyether-modified silicone. It is disclosed that the polishing rate of the layer can be sufficiently suppressed. However, the film to be polished by the polishing liquid is made of a material having a relative dielectric constant of 2.8, a high dielectric constant, a high mechanical strength, and a physical property that hardly changes. Therefore, when such a polishing liquid is used to polish a low dielectric constant insulating layer having a structure in which pores are present in the film (for example, a layer having a relative dielectric constant of 2.4 or less), the low dielectric constant insulating layer In addition to mechanical damage, the physical properties of the low dielectric constant insulating layer are changed, so that it is not suitable as a polishing liquid used in the second polishing step.

JP 2000-248265 A JP 2005-129637 A

  The object of the present invention has been made in view of the above circumstances, and surface defects such as material peeling and scratches are not polished when the insulating layer is chemically mechanically polished without changing the physical properties of the insulating layer. An aqueous dispersion for chemical mechanical polishing capable of obtaining a highly accurate polished surface without being generated on the surface, a chemical mechanical polishing method using the same, and a kit for preparing the aqueous dispersion for chemical mechanical polishing are provided. It is to be.

  The chemical mechanical polishing aqueous dispersion according to the first aspect of the present invention comprises (A) abrasive grains, (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid, (C) an organic acid other than (B), ( D) an oxidizing agent, (E) a nonionic surfactant having a triple bond, and (F) a dispersion medium, wherein the (A) abrasive grains have an average primary particle diameter of 5 to 55 nm and an association degree. 1.5 to 4.0 colloidal silica.

  In the chemical mechanical polishing aqueous dispersion, the (D) oxidizing agent may be hydrogen peroxide.

・・・・・（１）
（式中、ｎおよびｍはそれぞれ独立に１以上の整数であり、ｎ＋ｍ≦５０を満たす。） In the chemical mechanical polishing aqueous dispersion, the (E) nonionic surfactant may be represented by the following general formula (1).

(1)
(In the formula, n and m are each independently an integer of 1 or more and satisfy n + m ≦ 50.)

  In the chemical mechanical polishing aqueous dispersion, the ratio (B / E) of the blending amount of the (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid to the blending amount of the (E) nonionic surfactant is 0.00. It can be 01-5.

In the above chemical mechanical polishing aqueous dispersion, when the chemical mechanical polishing in the same conditions a conductive barrier layer and the first insulating layer, the polishing speed of the polishing rate (R _B) and the first insulating layer of said conductive barrier layer ( R _in-1) and the polishing rate ratio _{(R B / R in-1} ) can be 1.2 to 4.0.

In the chemical mechanical polishing aqueous dispersion, when each of the copper layer, the conductive barrier layer, the first insulating layer, and the second insulating layer having a higher dielectric constant than the first insulating layer is subjected to chemical mechanical polishing under the same conditions, The polishing rate ratio (R _B / R _M ) between the polishing rate (R _B ) of the conductive barrier layer and the polishing rate (R _M ) of the copper layer is 1.5 or more, and the polishing rate of the second insulating layer The polishing rate ratio (R _In-2 / R _M ) between (R _In-2 ) and the polishing rate (R _M ) of the copper layer is 0.9 to 2.5, and the second insulating layer The polishing rate ratio (R _In-2 / R _In-1 ) between the polishing rate (R _In-2 ) and the polishing rate (R _In-1 ) of the first insulating layer may be 0.5-5. .

In the chemical mechanical polishing aqueous dispersion described above, a copper layer, a conductive layer, and a conductive pad are prepared using a polishing pad containing a water-insoluble matrix material containing a crosslinked polymer and water-soluble particles dispersed in the water-insoluble matrix material. When each of the conductive barrier layer, the first insulating layer, and the second insulating layer having a higher dielectric constant than the first insulating layer is subjected to chemical mechanical polishing under the same conditions, the polishing rate (R _In-1 ) of the first insulating layer The polishing rate of the conductive barrier layer (R _B ), the polishing rate of the copper layer (R _M ), and the polishing rate of the second insulating layer (R _In-2 ) are R _In-2 > R _B > R _M > R _In-1 can be satisfied.

The chemical mechanical polishing method according to the second aspect of the present invention comprises:
A first polishing step that is provided on the insulating layer having a recess via a stopper layer, and chemically and mechanically polishes the metal layer embedded in the recess until the stopper layer is exposed;
And a second polishing step of chemically polishing the metal layer and the stopper layer until the insulating layer is exposed using the chemical mechanical polishing aqueous dispersion.

  In the chemical mechanical polishing method, the insulating layer includes a laminate of a first insulating layer and a second insulating layer having a dielectric constant higher than that of the first insulating layer, and the second polishing step includes the metal layer, The stopper layer and the second insulating layer may be chemically mechanically polished.

  In the chemical mechanical polishing method, the first dielectric layer may have a relative dielectric constant of 3.5 or less.

  In the chemical mechanical polishing method, the stopper layer may be a conductive barrier layer.

The kit for preparing the chemical mechanical polishing aqueous dispersion according to the third aspect of the present invention comprises:
A kit for preparing the chemical mechanical polishing aqueous dispersion by mixing the liquid (I) and the liquid (II),
The liquid (I) comprises (A) abrasive grains which are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.5 to 4.0, (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid (C) an organic acid other than (B), (E) a nonionic surfactant having a triple bond, and (F) an aqueous dispersion containing a dispersion medium,
The liquid (II) contains (D) an oxidizing agent.

The kit for preparing the chemical mechanical polishing aqueous dispersion according to the fourth aspect of the present invention comprises:
A kit for preparing the chemical mechanical polishing aqueous dispersion by mixing the liquid (I) and the liquid (II),
The liquid (I) is an aqueous dispersion containing (A) abrasive grains which are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.5 to 4.0, and (F) a dispersion medium. ,
The liquid (II) is (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid, (
C) An organic acid other than (B), (D) an oxidizing agent, and (E) a nonionic surfactant having a triple bond.

The kit for preparing the chemical mechanical polishing aqueous dispersion according to the fifth aspect of the present invention comprises:
A kit for mixing the liquid (I), the liquid (II), and the liquid (III) to prepare the chemical mechanical polishing aqueous dispersion,
The liquid (I) is an aqueous dispersion containing (A) abrasive grains which are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.5 to 4.0, and (F) a dispersion medium. ,
The liquid (II) contains (B) a quinolinecarboxylic acid and / or pyridinecarboxylic acid and (E) a nonionic surfactant having a triple bond,
The liquid (III) contains (D) an oxidizing agent.

In the kit according to the fourth or fifth aspect,
The liquid (I) comprises (B) a quinoline carboxylic acid and / or pyridine carboxylic acid, (C) an organic acid other than (B), (D) an oxidizing agent, and (E) a nonionic interface having a triple bond. One or more components selected from activators can be further included.

  By performing chemical mechanical polishing of the insulating layer using the above-mentioned chemical mechanical polishing aqueous dispersion, when the insulating layer is chemically mechanically polished, the physical properties of the insulating layer are not changed, and material peeling or scratching can be performed. A surface to be polished with high accuracy can be obtained without causing surface defects on the surface to be polished.

  For example, when chemical mechanical polishing is performed on a semiconductor substrate including an insulating layer having a low mechanical strength (for example, an insulating layer having a relative dielectric constant of 3.5 or less) as an interlayer insulating layer using the chemical mechanical polishing aqueous dispersion. In addition, it is possible to obtain a polished surface with high accuracy without causing surface defects such as material peeling or scratches on the polished surface without changing the physical properties of the insulating layer, and The polishing rate can be sufficiently suppressed. In particular, the chemical mechanical polishing aqueous dispersion is useful when used as an abrasive in the second polishing step when performing the two-step polishing process by the damascene method described above.

  Further, for example, when polishing a conductive barrier layer provided on the insulating layer, and when polishing a second insulating layer provided on the first insulating layer and having a relative dielectric constant higher than that of the first insulating layer. Without changing the physical properties of these insulating layers, it is possible to obtain a polished surface with high accuracy without causing surface defects such as material peeling and scratches on the polished surface.

Fig.1 (a)-FIG.1 (c) are schematic which shows one specific example of the chemical mechanical polishing method of this invention. FIG. 2A to FIG. 2C are schematic views showing another specific example of the chemical mechanical polishing method of the present invention. FIG. 3A to FIG. 3C are schematic views showing another specific example of the chemical mechanical polishing method of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  In addition, this invention is not limited to the following embodiment, Various modifications implemented in the range which does not change the summary of this invention are included.

1. Chemical mechanical polishing aqueous dispersion The chemical mechanical polishing aqueous dispersion according to one embodiment of the present invention includes (A) abrasive grains, (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid, and (C) other than (B) above. An organic acid, (D) an oxidizing agent, (E) a nonionic surfactant having a triple bond, and (F) a dispersion medium (hereinafter also referred to as “components (A) to (F)”). To do.

  Hereinafter, each component contained in the chemical mechanical polishing dispersion of one embodiment of the present invention will be described in detail.

1.1. (A) Abrasive grains (A) Abrasive grains are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.5 to 4.0. (A) When the degree of association of the abrasive grains is less than 1.5, the (E) component tends to adhere to the (A) abrasive grains. As a result, polishing is suppressed, and the polishing rate of the insulating layer tends to be slow. is there. On the other hand, when the degree of association of (A) abrasive grains exceeds 4.0, the polishing rate becomes too high, and a good surface to be polished may not be obtained.

  (A) The average primary particle diameter of the abrasive grains can be calculated by obtaining an average value of the particle diameters of 50 (A) abrasive grains by observation with a transmission electron microscope.

  Moreover, the average secondary particle diameter of (A) abrasive grains can be measured by a dynamic light scattering method or a laser scattering diffraction method. Of these, measurement by the laser scattering diffraction method is preferable because it is simple.

Further, (A) the degree of association of the abrasive grains is calculated from the average primary particle diameter and the average secondary particle diameter of the (A) abrasive grains calculated by the above method, using the following calculation formula.
Degree of association = (average secondary particle size) / (average primary particle size)

  Colloidal silica can be obtained, for example, by an inorganic colloid method using a raw material purified in advance.

  The (A) abrasive grains preferably have an impurity metal content of 10 ppm or less, more preferably 5 ppm or less, still more preferably 3 ppm or less, and particularly preferably 1 ppm or less with respect to the abrasive grains. Examples of the impurity metal include iron, nickel, and zinc.

  Further, the degree of association of (A) abrasive grains is preferably 1.9 to 3.8, more preferably 2.2 to 3.5.

  Furthermore, (A) The average primary particle diameter of an abrasive grain becomes like this. Preferably it is 10-45 nm, More preferably, it is 15-40 nm, More preferably, it is 20-35 nm. Moreover, (A) The average secondary particle diameter of an abrasive grain becomes like this. Preferably it is 60-170 nm, More preferably, it is 65-140 nm, More preferably, it is 70-120 nm. By using the (A) abrasive grains having an association degree, an average primary particle diameter, and an average secondary particle diameter in this range, a good balance between the polished surface and the polishing rate can be achieved. (A) By using colloidal silica having an average primary particle diameter of abrasive grains of 5 to 55 nm and an association degree of 1.5 to 4.0, an object to be polished (especially a conductive barrier layer and / or an insulating layer) can be obtained. When polishing, both a good surface to be polished and a polishing rate can be obtained.

  (A) The quantity of an abrasive grain is 0.05-10 mass% with respect to the total amount of the chemical mechanical polishing aqueous dispersion, Preferably it is 2-7 mass%.

  In the chemical mechanical polishing aqueous dispersion according to this embodiment, for example, the pH is adjusted to 7 to 12 (preferably 7.5 to 11), the average primary particle diameter is 5 to 55 nm, and the degree of association is 1.5. The polishing rate of the conductive barrier layer can be increased by including (A) abrasive grains that are ˜4.0 colloidal silica.

1.2. (B) Quinoline carboxylic acid and / or pyridine carboxylic acid (B) Quinoline carboxylic acid used as quinoline carboxylic acid and / or pyridine carboxylic acid (hereinafter also referred to as component (B)) includes, for example, unsubstituted quinoline Examples thereof include substituted quinoline carboxylic acids in which one or more hydrogen atoms are substituted with hydroxyl groups, halogen atoms, or the like at a site other than the carboxyl group of carboxylic acid or quinoline carboxylic acid.

  Examples of the pyridinecarboxylic acid include unsubstituted pyridinecarboxylic acid and substituted pyridinecarboxylic acid in which one or more hydrogen atoms are substituted with a hydroxyl group, a halogen atom, or the like at a site other than the carboxyl group of pyridinecarboxylic acid. It is done.

  Of these, unsubstituted quinoline carboxylic acid and unsubstituted pyridine carboxylic acid are preferable, and 2-quinoline carboxylic acid (quinaldic acid) and 2,3-pyridinedicarboxylic acid (quinolinic acid) are particularly preferable. The quinoline carboxylic acid and the pyridine carboxylic acid may each be a carboxylate obtained by blending a salt such as a potassium salt or an ammonium salt.

  The blending amount of the component (B) is preferably 0.001 to 2% by mass, more preferably 0.005 to 1% by mass, based on the total amount of the chemical mechanical polishing aqueous dispersion according to this embodiment. In particular, it is 0.01 to 0.5% by mass. When the blending amount of the component (B) is less than 0.001% by mass, a sufficient copper film polishing rate may not be obtained. On the other hand, when the blending amount of the component (B) exceeds 2% by mass, other components cannot be contained in a desired blending amount.

  The chemical mechanical polishing aqueous dispersion according to this embodiment has a pH of 7 to 12 (preferably 7.5 to 11), and includes a component (B). The polishing rate of the layer) can be controlled within an appropriate range.

1.3. (C) Organic acid other than (B) (C) The organic acid other than (B) is preferably an aliphatic organic acid having 4 or more carbon atoms, for example. As the aliphatic organic acid having 4 or more carbon atoms, for example, an aliphatic polycarboxylic acid having 4 or more carbon atoms, a hydroxyl acid having 4 or more carbon atoms, or the like is preferable. Specific examples of the aliphatic polycarboxylic acid having 4 or more carbon atoms include maleic acid, succinic acid, fumaric acid, glutaric acid, adipic acid and the like. Specific examples of the hydroxyl acid having 4 or more carbon atoms include citric acid, malic acid, tartaric acid and the like. Of these, aliphatic organic acids having 4 to 8 carbon atoms are more preferable, aliphatic organic acids having 4 to 6 carbon atoms are more preferable, and maleic acid, citric acid, and malic acid are particularly preferable.

  (C) The amount of the organic acid other than (B) is preferably 0.005 to 3 mass%, more preferably 0.05 to 2 mass%, based on the total amount of the chemical mechanical polishing aqueous dispersion. More preferably, it is 0.1-1 mass%.

1.4. (D) Oxidizing agent (D) Examples of the oxidizing agent include persulfates, hydrogen peroxide, inorganic acids, organic peroxides, and polyvalent metal salts. Examples of the persulfate include ammonium persulfate and potassium persulfate. Examples of the inorganic acid include nitric acid and sulfuric acid. Examples of the organic peroxide include peracetic acid, perbenzoic acid, tert-butyl hydroperoxide, and the like. Examples of the polyvalent metal salt include permanganic acid compounds and dichromic acid compounds. Specifically, examples of the permanganic acid compound include potassium permanganate and the like. And potassium chromate. Of these, hydrogen peroxide, persulfates and inorganic acids are preferred, and hydrogen peroxide is particularly preferred.

  (D) The amount of the oxidizing agent is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, and still more preferably based on the total amount of the chemical mechanical polishing aqueous dispersion. It is 0.05-1.5 mass%.

・・・・・（１）
（式中、ｎおよびｍはそれぞれ独立に１以上の整数であり、ｎ＋ｍ≦５０を満たす。） 1.5. (E) Nonionic surfactant having triple bond (E) Nonionic surfactant having triple bond (hereinafter also referred to as component (E)) is represented by, for example, the following general formula (1). The compound which is made is mentioned.

(1)
(In the formula, n and m are each independently an integer of 1 or more and satisfy n + m ≦ 50.)

  In the general formula (1), n + m ≦ 40 is preferable, and n + m ≦ 30 is more preferable.

  Examples of commercially available products of component (E) include Surfinol 440 (HLB value = 8), Surfinol 465 (2,4,7,9-tetramethyl-5-decyne-4,7-diol-dipolyoxy Ethylene ether, HLB value = 13), Surfynol 485 (2,4,7,9-tetramethyl-5-decyne-4,7-diol-dipolyoxyethylene ether, HLB value = 17) (above, air products Japan Co., Ltd.).

  The amount of the component (E) represented by the general formula (1) is preferably 0.001 to 4% by mass, more preferably 0.01% with respect to the total amount of the chemical mechanical polishing aqueous dispersion. It is -2 mass%.

  Moreover, in the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention, the ratio of the blending amount of the component (B) to the blending amount of the component (E) is preferably 0.1 to 5. As a result, it is possible to obtain a highly polished surface that is well planarized without damaging the physical properties of the insulating layer.

1.6. (F) Dispersion medium (F) Examples of the dispersion medium include a mixed medium of water, water and alcohol, a mixed medium containing water and an organic solvent compatible with water, and the like. Of these, water or a mixed medium of water and alcohol is preferably used, and water is particularly preferably used.

1.7. Other Components The chemical mechanical polishing aqueous dispersion of one embodiment of the present invention contains the above components (A) to (F) as essential components, but, if necessary, (G) an anticorrosive, ( H) A pH adjusting agent can be contained.

  (G) As an anticorrosive agent, benzotriazole and its derivative (s) can be mentioned. Here, the benzotriazole derivative means one obtained by substituting one or two or more hydrogen atoms of benzotriazole with, for example, a carboxyl group, a methyl group, an amino group, or a hydroxyl group. Examples of the benzotriazole derivative include 4-carboxylbenzotriazole and its salt, 7-carboxybenzotriazole and its salt, benzotriazole butyl ester, 1-hydroxymethylbenzotriazole, 1-hydroxybenzotriazole and the like.

  (G) The amount of the anticorrosive is preferably 0.005 to 0.1% by mass, more preferably 0.01 to 0.05% by mass, based on the total amount of the chemical mechanical polishing aqueous dispersion. .

  (H) As a pH adjuster, an organic base, an inorganic base, or an inorganic acid can be mentioned. Examples of the organic base include tetramethylammonium hydroxide and triethylamine. Examples of the inorganic base include ammonia, potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide and the like. Examples of the inorganic acid include nitric acid, sulfuric acid, hydrochloric acid, acetic acid and the like.

  The pH of the chemical mechanical polishing aqueous dispersion according to one embodiment of the present invention is 7 to 12, preferably 7.5 to 11, and more preferably 7.5 to 10. By setting the pH within this range, a good balance between the polished surface and the polishing rate can be achieved.

  The amount of the (H) pH adjuster is preferably 0.005 to 5 mass%, more preferably 0.01 to 3.5 mass%, based on the total amount of the chemical mechanical polishing aqueous dispersion.

1.8. Kit for Preparing Chemical Mechanical Polishing Aqueous Dispersion The chemical mechanical polishing aqueous dispersion can be supplied in a state where it can be used as a polishing composition as it is after the preparation. Alternatively, a polishing composition (that is, a concentrated polishing composition) containing each component of the chemical mechanical polishing aqueous dispersion at a high concentration is prepared, and the concentrated polishing composition is used at the time of use. It may be diluted to obtain a desired chemical mechanical polishing aqueous dispersion.

  For example, the chemical mechanical polishing aqueous dispersion may be prepared by dividing it into a plurality of liquids (for example, two or three liquids), and these liquids may be mixed and used at the time of use. For example, the chemical mechanical polishing aqueous dispersion can be prepared by mixing a plurality of liquids using the following first to third kits.

1.8.1. First Kit The first kit is a kit for preparing the chemical mechanical polishing aqueous dispersion by mixing the liquid (I) and the liquid (II). In the first kit, the liquid (I) contains (A) abrasive grains that are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.5 to 4.0, (B) quinolinecarboxylic acid, and And / or (C) an aqueous dispersion containing (C) an organic acid other than (B), (E) a nonionic surfactant having a triple bond, and (F) a dispersion medium. Includes (D) an oxidizing agent.

When preparing the liquid (I) and the liquid (II) constituting the first kit, the respective components described above are described in the aqueous dispersion obtained by mixing the liquid (I) and the liquid (II). It is necessary to determine the concentration of each component contained in the liquid (I) and the liquid (II) so as to be included in the concentration range. In addition, the liquid (I) and the liquid (II) may contain each component at a high concentration (that is, may be concentrated). In this case, the liquid (I) and the liquid (D) are diluted at the time of use. It is possible to obtain (II). According to the first kit, the storage stability of the oxidizing agent (D) can be improved by separating the liquid (I) and the liquid (II).

  When preparing the chemical mechanical polishing aqueous dispersion using the first kit, it is sufficient that the liquid (I) and the liquid (II) are separately prepared and supplied and integrated together during polishing. The method and timing are not particularly limited.

  For example, the liquid (I) and the liquid (II) may be separately supplied to the polishing apparatus and mixed on the surface plate, or may be mixed before being supplied to the polishing apparatus, or in the polishing apparatus. Or may be mixed in the mixing tank by providing a mixing tank. Further, a line mixer or the like may be used in order to obtain a more uniform aqueous dispersion during line mixing.

1.8.2. Second Kit The second kit is a kit for preparing the chemical mechanical polishing aqueous dispersion by mixing the liquid (I) and the liquid (II). In the second kit, the liquid (I) contains (A) abrasive grains that are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.5 to 4.0, and (F) a dispersion medium. It is an aqueous dispersion, and the liquid (II) comprises (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid, (C) an organic acid other than (B), (D) an oxidizing agent, and (E) a triple bond. Having a nonionic surfactant.

  When preparing the liquid (I) and the liquid (II) constituting the second kit, the respective components described above are contained in the aqueous dispersion obtained by mixing the liquid (I) and the liquid (II). It is necessary to determine the concentration of each component contained in the liquid (I) and the liquid (II) so as to be included in the concentration range. In addition, the liquid (I) and the liquid (II) may contain each component at a high concentration (that is, may be concentrated). In this case, the liquid (I) and the liquid (D) are diluted at the time of use. It is possible to obtain (II). According to the second kit, the storage stability of the aqueous dispersion can be improved by separating the liquid (I) and the liquid (II).

  When the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention is prepared using the second kit, the liquid (I) and the liquid (II) are separately prepared and supplied, and are integrated during polishing. The mixing method and timing are not particularly limited.

  For example, the liquid (I) and the liquid (II) may be separately supplied to the polishing apparatus and mixed on the surface plate, or may be mixed before being supplied to the polishing apparatus, or in the polishing apparatus. Or may be mixed in the mixing tank by providing a mixing tank. Further, a line mixer or the like may be used in order to obtain a more uniform aqueous dispersion during line mixing.

1.8.3. Third Kit The third kit is a kit for preparing the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention by mixing the liquid (I), the liquid (II), and the liquid (III). It is. In the third kit, the liquid (I) includes (A) abrasive grains that are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.5 to 4.0, and (F) a dispersion medium. Liquid dispersion (II) includes (B) quinoline carboxylic acid and / or pyridine carboxylic acid and (E) a nonionic surfactant having a triple bond, and liquid (III) is (D) Contains oxidant.

  When preparing liquid (I), liquid (II), and liquid (III) constituting the third kit, an aqueous system obtained by mixing liquid (I), liquid (II), and liquid (III) It is necessary to determine the concentration of each component contained in the liquid (I), the liquid (II), and the liquid (III) so that the above-described components are included in the dispersion in the concentration range described above. In addition, liquid (I), liquid (II), and liquid (III) may each contain a high concentration of each component (that is, it may be concentrated). , Liquid (I), liquid (II), and liquid (III) can be obtained. According to the third kit, the storage stability of the aqueous dispersion can be increased by separating the liquid (I), the liquid (II), and the liquid (III).

  When preparing the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention using the third kit, the liquid (I), the liquid (II), and the liquid (III) are separately prepared and supplied, and There is no particular limitation on the mixing method and timing as long as they are integrated during polishing.

  For example, the liquid (I), the liquid (II), and the liquid (III) may be separately supplied to the polishing apparatus and mixed on the surface plate, or may be mixed before being supplied to the polishing apparatus. Then, line mixing may be performed in the polishing apparatus, or mixing may be performed by providing a mixing tank. Further, a line mixer or the like may be used in order to obtain a more uniform aqueous dispersion during line mixing.

  In the second and third kits, the liquid (I) contains (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid, (C) an organic acid other than (B), (D) an oxidizing agent, and ( E) One or more components selected from nonionic surfactants having a triple bond may be further included.

1.9. Use The chemical mechanical polishing aqueous dispersion of one embodiment of the present invention can be used as an abrasive for chemical mechanical polishing an insulating layer contained in a semiconductor device. For example, the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention can be used as an abrasive when forming a copper (or copper alloy) damascene wiring by chemical mechanical polishing. In this case, the step of forming the copper (or copper alloy) damascene wiring by chemical mechanical polishing is formed mainly in the first polishing step for removing copper (or copper alloy) and mainly under the copper (or copper alloy). And a second polishing step for removing the conductive barrier layer. In this second polishing step, not only the conductive barrier layer is removed, but also the insulating layer existing under the conductive barrier layer may be polished at the same time. Can be obtained. Here, the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention can be suitably used as an abrasive in the second polishing step. By using the chemical mechanical polishing aqueous dispersion as an abrasive in the second polishing step, more excellent polishing characteristics and low damage to an insulating layer (especially an insulating layer having a relative dielectric constant of 3.5 or less). Can be demonstrated.

As the insulating layer, silsesquioxane (relative dielectric constant: about 2.6 to 3.0), fluorine-added SiO ₂ (relative dielectric constant: about 3.3 to 3.5), polyimide resin (relative dielectric) Rate; about 2.4 to 3.6), benzocyclobutene (relative permittivity; about 2.7), hydrogen-containing SOG (relative permittivity; about 2.5 to 3.5) and organic SOG (relative permittivity) About 2.9) and the like. Among these, the interlayer insulating layer mainly composed of silsesquioxane has a film thickness of 0.2 to 20 μm, a density of 0.3 to 1.85 g / cm ³ , and a fine pore diameter of 100 nm or less. Examples thereof include a porous insulating layer having various pores.

The insulating layer having a relative dielectric constant of 3.5 or less has an elastic modulus of 20 GPa or less, preferably 10 GPa or less, more preferably 5 GPa or less. The elastic modulus of the insulating layer can be measured by a continuous stiffness measurement method by attaching a Barcovic indenter to an ultra-small hardness meter (Nanoindentator XP) manufactured by MTS. The chemical mechanical polishing aqueous dispersion of one embodiment of the present invention can be suitably used for polishing such a brittle insulating layer.

  In addition, the said insulating layer can be used as the 1st insulating layer 21 mentioned later (refer Fig.2 (a)-FIG.2 (c)).

  A chemical mechanical polishing aqueous dispersion according to an embodiment of the present invention, a water-insoluble matrix material containing a crosslinked polymer, and a polishing pad containing water-soluble particles dispersed in the water-insoluble matrix material. In particular, when an insulating layer having an elastic modulus of 20 GPa or less measured by a continuous stiffness measurement method is chemically mechanically polished, generation of scratches on the surface to be polished is suppressed to 5 or less, which is particularly preferable.

  The presence or absence of scratches can be observed visually, but the size, number, etc., of quantitative measurements should be made by methods such as observation with an optical microscope, scanning electron microscope, etc., and analysis of the photographed photos. Can do. It is also possible to use a specific apparatus for inspecting the surface state capable of measuring the total number of scratches generated on the surface to be polished.

In the chemical mechanical polishing aqueous dispersion according to this embodiment, when the conductive barrier layer and the insulating layer are subjected to chemical mechanical polishing under the same conditions, the polishing rate (R _B ) of the conductive barrier layer and the polishing rate (R of the insulating layer) _{an in-1)} and the polishing rate ratio _{(R B / R in-1} ) can be 1.2 to 4.0. Thereby, for example, in the polishing shown in FIG. 2B and FIG. 2C described later, the unevenness of the surface to be polished can be reduced to the minimum, so that excellent flatness can be obtained, and A good surface to be polished and a polishing rate can be obtained. For example, in the case of forming a multilayer wiring including an upper wiring portion and a lower wiring portion using the chemical mechanical polishing aqueous dispersion according to the present embodiment, the upper wiring portion includes an insulating layer and an insulating layer. When the conductive barrier layer that covers the surface of the provided recess and the conductive layer provided on the conductive barrier layer and embedded in the recess are included, distortion of the upper wiring portion can be suppressed.

In addition, the chemical mechanical polishing aqueous dispersion according to the present embodiment uses a copper layer, a conductive barrier layer, a first insulating layer, and a second insulating layer having a dielectric constant higher than that of the first insulating layer under the same conditions. When mechanically polished, the polishing rate ratio (R _B / R _M ) between the polishing rate (R _B ) of the conductive barrier layer and the polishing rate (R _M ) of the copper layer is 1.5 or more, and the second insulating layer The polishing rate ratio (R _In-2 / R _M ) between the polishing rate (R _In-2 ) and the polishing rate (R _M ) of the copper layer is 0.9 to 2.5, and
In the polishing rate ratio between the polishing rate of the second insulating layer polishing rate _{(R In-2)} and the first insulating layer _{(R In-1) (R} In-2 / R In-1) is 0.5 to 5 Can be. Thereby, in the polishing shown in FIGS. 2A to 2C described later, a good surface to be polished and a polishing rate can be obtained.

Further, the chemical mechanical polishing aqueous dispersion according to this embodiment uses a polishing pad containing a water-insoluble matrix material containing a crosslinked polymer and water-soluble particles dispersed in the water-insoluble matrix material. When each of the copper layer, the conductive barrier layer, the first insulating layer, and the second insulating layer having a higher dielectric constant than the first insulating layer is subjected to chemical mechanical polishing under the same conditions, the polishing rate of the first insulating layer ( R _In-1 ), the polishing rate of the conductive barrier layer (R _B ), the polishing rate of the copper layer (R _M ), and the polishing rate of the second insulating layer (R _In-2 ) are R _In-2 > R _B > R _M > R _In−1 can be satisfied. Thereby, in the polishing shown in FIG. 2B and FIG. 2C described later, the polishing of the first insulating layer is suppressed as much as possible, and the copper layer, the conductive barrier layer, and the second insulating layer are selectively selected. It can be removed and a good surface to be polished and a polishing rate can be obtained.

2. Chemical Polishing Method A chemical mechanical polishing method according to an embodiment of the present invention is a method in which a metal layer provided on an insulating layer having a recess via a stopper layer is embedded in the recess until the stopper layer is exposed. A first polishing step for mechanical polishing and a second polishing step for chemical mechanical polishing of the metal layer and the stopper layer until the insulating layer is exposed using the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention. And including. Hereinafter, although the specific example of the chemical mechanical polishing method of one embodiment of this invention is demonstrated with reference to FIGS. 1-3, the chemical mechanical polishing method of one embodiment of this invention is not limited to these.

2.1. First Specific Example FIGS. 1A to 1C are cross-sectional views schematically showing a specific example (first specific example) of a chemical mechanical polishing method according to an embodiment of the present invention.

  Fig.1 (a) shows the grinding | polishing target object 1a of the chemical mechanical polishing method of a 1st specific example. As shown in FIG. 1A, the object to be polished 1a is provided on a substrate 11, an insulating layer 12 including a recess 20 provided on the substrate 11, and a stopper layer 13 on the insulating layer 12. Metal layer 14. The metal layer 14 is embedded in the recess 20. Here, the substrate 11 is, for example, a silicon substrate, the insulating layer 12 may be an inorganic material or an organic material, and the stopper layer 13 is a layer having a different etching rate from the metal layer 14 with respect to the abrasive, The metal layer 14 is generally made of a metal material that can be used as wiring. The insulating layer 12 can be composed of, for example, a PETEOS film or an insulating layer having a relative dielectric constant of 3.5 or less, preferably an insulating layer having a relative dielectric constant of 3.5 or less, more preferably 3.0. The following insulating layers. The stopper layer 13 is preferably made of, for example, a conductive barrier layer. Furthermore, the metal layer 14 can be made of a metal generally used for wiring (for example, a metal such as aluminum, copper, or gold, or an alloy of the metal), and is preferably copper or a copper alloy.

  When the stopper layer 13 is made of a conductive barrier layer, it can be made of, for example, a metal, a metal alloy, or a metal nitride (for example, Ti, TiN, Ta, TaN, TaNb). Here, the material of the stopper layer 13 is particularly preferably Ta and / or TaN. The stopper layer 13 may have a two-layer structure.

  First, in the first polishing step, chemical mechanical polishing is performed until the stopper layer 13 is exposed except for the portion of the metal layer 14 buried in the recess 20 (see FIG. 1B). Here, as the abrasive, the chemical mechanical polishing aqueous dispersion described above may be used, or the first polishing aqueous dispersion described later may be used.

  Next, in the second polishing step, the remaining metal layer 14 and the stopper layer 13 are subjected to chemical mechanical polishing until the insulating layer 12 is exposed using the chemical mechanical polishing aqueous dispersion according to the embodiment of the present invention described above ( (Refer FIG.1 (c)). Thereby, the part located in the stopper layer 13 other than the bottom part and inner wall surface of the recessed part 20 is removed. As a result, the wiring structure 1 shown in FIG. 1C is obtained.

  According to this specific example, in the second polishing step, the physical properties of the insulating layer 12 are not changed and the material is peeled off by chemically mechanically polishing the insulating layer 12 using the above-described chemical mechanical polishing aqueous dispersion. A surface to be polished with high accuracy can be obtained without causing surface defects such as scratches and scratches on the surface to be polished. In particular, when the insulating layer 12 is made of an insulating layer having a relative dielectric constant of 3.5 or less, the occurrence of the surface defects on the polished surface can be prevented without changing the physical properties of the insulating layer 12. Very useful in terms.

2.2. Second Specific Example FIGS. 2A to 2C are cross-sectional views schematically showing another specific example (second specific example) of the chemical mechanical polishing method of one embodiment of the present invention. is there.

  Fig.2 (a) shows the grinding | polishing target object 2a of the chemical mechanical polishing method of a 2nd specific example. In FIG. 2A, except that the insulating layer 112 includes a stacked body of the first insulating layer 21 and the second insulating layer 22 having a dielectric constant higher than that of the first insulating layer 21, FIG. The same components as those shown in FIG. 1A are denoted by the same reference numerals. Here, the second insulating layer 22 has a function as a cap layer.

  The second insulating layer 22 is, for example, a silicon oxide film, a boron phosphorus silicate film (BPSG film) obtained by adding a small amount of boron and phosphorus to silicon oxide, and an oxide called FSG (Fluorine-doped silicon glass) doped with fluorine in silicon oxide. A silicon-based insulating layer may be used. Examples of the silicon oxide insulating layer include a thermal oxide film, a PETEOS (Plasma Enhanced-TEOS film), an HDP film (High Density Plasma Enhanced-TEOS film), and a silicon oxide film obtained by a thermal CVD method. In other words, the second insulating layer 22 preferably has a relatively hydrophilic surface made of silicon oxide or the like.

  The first insulating layer 21 is made of, for example, an HSQ film (Hydrogen Silsesquioxane film) using triethoxysilane as a raw material, an MSQ film (Methyl Silsesquioxane film) using tetraethoxysilane and a small amount of methyltrimethoxysilane as a raw material, or other silane compounds. It consists of a film as a raw material. Further, the first insulating layer 21 is made by mixing suitable organic polymer particles or the like into the raw material, so that the polymer is burned out in the heating process to form vacancies, thereby further reducing the dielectric constant. It may be a membrane. Alternatively, the first insulating layer 21 may be an organic polymer such as a polyarylene polymer, a polyarylene ether polymer, a polyimide polymer, or a benzocyclobutene polymer. The first insulating layer 21 is preferably an insulating layer having a relative dielectric constant of 3.5 or less, more preferably an insulating layer having a dielectric constant of 3.0 or less. That is, the first insulating layer 21 may be a layer containing a hydrophobic functional group of an alkyl group (such as a methyl group) in the main chain in order to lower the relative dielectric constant.

  First, in the first polishing step, chemical mechanical polishing is performed until the stopper layer 13 is exposed except for the portion of the metal layer 14 buried in the recess 20 (see FIG. 2B). Here, as the abrasive, the chemical mechanical polishing aqueous dispersion of one embodiment of the present invention may be used, or a first polishing aqueous dispersion described later may be used.

  Next, in the second polishing step, the remaining metal layer 14, the stopper layer 13, and the second, using the chemical mechanical polishing aqueous dispersion (second polishing aqueous dispersion) of the embodiment of the present invention described above. Chemical mechanical polishing is performed on the insulating layer 22 until the first insulating layer 21 is exposed (see FIG. 2C). Thereby, the part located in the stopper layer 13 other than the bottom part and inner wall surface of the recessed part 20 is removed. As a result, the wiring structure 2 shown in FIG. 2C is obtained.

  According to this example, the same effect as the first example described above is obtained. In addition, according to this specific example, in the second polishing step, the second insulating layer 22 is selectively removed by chemical mechanical polishing, so that damage to the first insulating layer 21 by chemical mechanical polishing is reduced. Can do.

For example, when the first insulating layer 21 is a layer containing a hydrophobic functional group in the main chain and the first insulating layer 22 has a surface made of silicon oxide having a relatively hydrophilic property, the second polishing aqueous system is used. By polishing the first insulating layer 21 using the dispersion, the (E) surfactant contained in the second polishing aqueous dispersion is the surfactant represented by the general formula (1). Therefore, (E) the hydrophobic portion of the surfactant has a high affinity with the hydrophobic surface of the first insulating layer 21. Therefore, (E) the surfactant is adsorbed on the surface of the first insulating layer 21 to protect the surface. As a result, (A)
Direct polishing by abrasive grains can be suppressed, and an increase in polishing rate can be suppressed.

2.3. Third Specific Example FIGS. 3A to 3C are diagrams schematically illustrating another specific example (third specific example) of the chemical mechanical polishing method according to the embodiment of the present invention. .

  FIG. 3A shows a polishing object 3a of the chemical mechanical polishing method of the third specific example. 3A has the same structure as that shown in FIG. 1A except that a third insulating layer 31 and a fourth insulating layer 32 are provided below the insulating layer 12. The same components as those shown in FIG. 1A are given the same symbols. Here, the third insulating layer 31 is made of, for example, silicon oxide, and the fourth insulating layer 32 is made of, for example, silicon nitride.

  The chemical mechanical polishing method of this specific example is the same as the chemical polishing method of the first specific example. Further, according to this specific example, the same effect as the first specific example described above is obtained.

2.4. Polishing apparatus and polishing conditions In the chemical mechanical polishing method of one embodiment of the present invention, polishing in the first polishing process and the second polishing process is performed using commercially available chemical mechanical polishing apparatuses (for example, LGP510, LGP552 (hereinafter referred to as lap master SFT). ), EPO-112, EPO-222 (above, manufactured by Ebara Corporation), Mirra (Applied Materials), AVANTI-472 (made by Ipec), etc.) It can be done under conditions.

Preferred polishing conditions should be appropriately set depending on the chemical mechanical polishing apparatus used. For example, when EPO-112 is used as the chemical mechanical polishing apparatus, both the first polishing process and the second polishing process are, for example, the following: It can be a condition.
Surface plate rotation speed: preferably 30 to 130 rpm, more preferably 40 to 130 rpm
Head rotation speed: preferably 30 to 130 rpm, more preferably 40 to 130 rpm
Surface plate rotation speed / head rotation speed ratio: preferably 0.5 to 2, more preferably 0.7 to 1.5
Polishing pressure: preferably 0.5 to 2.5 psi, more preferably 1.0 to 2.0 psi
Chemical mechanical polishing aqueous dispersion supply rate: preferably 50 to 300 ml / min, more preferably 100 to 200 ml / min

2.5. First Polishing Aqueous Dispersion In the first to third specific examples, the first polishing aqueous dispersion that can be used in the first polishing step is the same for each of the metal layer 14 and the stopper layer 13. A chemical machine having a polishing characteristic in which the polishing rate ratio (R _M / R _S ) between the polishing rate (R _M ) of the metal layer 14 and the polishing rate (R _S ) of the stopper layer 13 is 50 or more when chemical mechanical polishing is performed. It can be an aqueous dispersion for polishing. Here, if the polishing rate ratio (R _M / R _S ) is less than 50, after the first polishing step is completed, excessive metal remains in a portion where the metal layer 14 is to be removed, so that the second polishing is performed. A lot of time is required for the process, and a large amount of machining liquid may be required.

The polishing rate ratio (R _M / R _S ) of the first polishing aqueous dispersion is preferably 60 or more, more preferably 70 or more.

The composition of the first aqueous dispersion for polishing is not particularly limited as long as the polishing rate ratio (R _M / R _S ) is in the above range. For example, in the aqueous medium, (A ) Abrasive grains, (C) an organic acid other than (B), (D) an oxidant, (F) a dispersion medium, and at least one ammonia component selected from the group consisting of ammonia and ammonium ions. Is preferred.

  The (F) dispersion medium used in the first polishing aqueous dispersion is exemplified as the (F) dispersion medium in the chemical mechanical polishing aqueous dispersion (second polishing aqueous dispersion) of the present embodiment, for example. Among these, it is preferable to use only water as a dispersion medium.

  Examples of the (A) abrasive grains used in the first polishing aqueous dispersion include inorganic particles.

  Examples of the inorganic particles include particles such as silica, alumina, titania, zirconia, and ceria, more preferably silica and ceria particles, and still more preferably silica. Examples of the silica include fumed silica, silica synthesized by a sol-gel method, and colloidal silica. Fumed silica can be obtained by reacting silicon chloride or the like with oxygen and water in the gas phase. Silica synthesized by the sol-gel method can be obtained by hydrolysis and / or condensation reaction using an alkoxysilicon compound as a raw material. Colloidal silica can be obtained, for example, by an inorganic colloid method using a raw material purified in advance.

Examples of the organic acid other than (C) (B) used in the first polishing aqueous dispersion include organic acids constituting the component (C) in the second polishing aqueous dispersion. Of these, citric acid and malic acid are preferably used in that a larger polishing rate ratio (R _M / R _S ) can be obtained.

  Further, the first polishing aqueous dispersion may further contain (G) an anticorrosive, glycine, and alanine. As the (G) anticorrosive used in the first polishing aqueous dispersion, for example, those exemplified as the (G) anticorrosive in the second polishing aqueous dispersion can be used, for example, carboxybenzotriazole. Can be mentioned.

  When the first polishing aqueous dispersion contains (G) an anticorrosive, the blending amount thereof is preferably 5% by mass or less, based on the total amount of the first polishing aqueous dispersion, 0.001 to 5 More preferably, it is more preferably 0.005 to 1% by mass, and particularly preferably 0.01 to 0.5% by mass.

  Examples of the (D) oxidizing agent used in the first polishing aqueous dispersion include those exemplified as the (D) oxidizing agent in the second polishing aqueous dispersion, and at least one selected from these examples. The oxidizing agent can be used. Of these, hydrogen peroxide or persulfate is preferable, and ammonium persulfate is particularly preferably used.

  The ammonia component contained in the first polishing aqueous dispersion may be present as ammonia, may be present as ammonium ions, or may be a mixture of both. The ammonium ions may be present in a free state, may be present as an ammonium salt of an acid, or both may be present in an equilibrium state. Such ammonia and ammonium ions may be generated by independently adding aqueous ammonia to the first polishing aqueous dispersion, such as the above-mentioned ammonium salts of organic acids or ammonium persulfate added as an oxidizing agent. You may produce | generate from the ammonium salt of an inorganic acid, or you may add as a counter cation of the anionic surfactant mentioned later.

  The first polishing aqueous dispersion includes (A) abrasive grains, (C) an organic acid other than (B), (D) an oxidizing agent, and at least one ammonia selected from the group consisting of ammonia and ammonium ions. The components are preferably contained in the following proportions.

(A) The compounding quantity of an abrasive grain is 0.001-3 mass% normally with respect to the total amount of the 1st polishing aqueous dispersion, Preferably it is 0.01-3 mass%, More preferably, it is 0. 0.01 to 2.5% by mass, more preferably 0.01 to 2% by mass.

  (C) The compounding quantity of organic acids other than said (B) is 0.01-10 mass% normally with respect to the total amount of the 1st grinding | polishing aqueous dispersion, Preferably it is 0.1-5 mass%. is there.

  (D) The compounding quantity of an oxidizing agent is 0.01-10 mass% normally with respect to the total amount of the 1st polishing aqueous dispersion, Preferably it is 0.02-5 mass%.

  The compounding amount of the ammonia component is usually 0.005 to 20 mol, preferably 0.01 to 15 mol, more preferably 0.03 to 10 mol, with respect to 1 liter of the first polishing aqueous dispersion. 0.05-10 mol is particularly preferable.

  The first polishing aqueous dispersion may further contain additives such as a surfactant and an antifoaming agent as necessary.

  Examples of the surfactant include a cationic surfactant, an anionic surfactant, an amphoteric surfactant, a nonionic surfactant, a water-soluble polymer, and the like, and in particular, an anionic surfactant and a nonionic surfactant. An agent or a water-soluble polymer is preferably used.

  Examples of the anionic surfactant include carboxylate, sulfonate, sulfate ester salt and phosphate ester salt. Examples of the carboxylate include fatty acid soaps and alkyl ether carboxylates, and examples of the sulfonate include alkylbenzene sulfonate, alkyl naphthalene sulfonate, α-olefin sulfonate, and the like. Examples of the sulfate ester salt include a higher alcohol sulfate ester salt, an alkyl ether sulfate salt, a polyoxyethylene alkylphenyl ether sulfate salt, and the like. Examples of the phosphate ester salt include an alkyl phosphorus salt. Examples include acid ester salts. Of these, sulfonates are preferred, alkylbenzene sulfonates are more preferred, and potassium dodecylbenzene sulfonate is particularly preferred.

  Examples of the nonionic surfactant include a nonionic surfactant such as a polyethylene glycol type surfactant, acetylene glycol, an ethylene oxide adduct of acetylene glycol, and acetylene alcohol.

  Examples of the water-soluble polymer include an anionic polymer, a cationic polymer, an amphoteric polymer, and a nonionic polymer. Examples of the anionic polymer include polyacrylic acid and its salt, polymethacrylic acid and its salt, and polyvinyl alcohol. Examples of the cationic polymer include polyethyleneimine and polyvinylpyrrolidone. Examples of the amphoteric polymer include polyacrylamide, and examples of the nonionic polymer include polyethylene oxide and polypropylene oxide.

  The compounding amount of the surfactant is preferably 20% by mass or less, more preferably 0.001 to 20% by mass, and more preferably 0.01 to 10% with respect to the total amount of the first polishing aqueous dispersion. More preferably, it is 0.05 mass%, Most preferably, it is 0.05-5 mass%.

The pH of the first polishing aqueous dispersion may be set to any value of an acidic region, a neutral region (from weakly acidic region to weakly alkaline region), and an alkaline region. The pH in the acidic region is preferably 2 to 4, the pH in the region near neutral is preferably 6 to 8, and the pH in the alkaline region is 8 to 8.
12 is preferred. Among these, pH in the neutral to alkaline region, that is, 6 to 12 is preferable.

  In the present invention, the first polishing step and the second polishing step may be performed continuously by using the same polishing apparatus and sequentially switching the supplied polishing aqueous dispersion while the object to be polished is mounted. In addition, using the same polishing apparatus, after the first polishing step is finished, the polishing object is once taken out, and after switching the polishing aqueous dispersion to be supplied, the removed polishing object is mounted again to perform the second polishing step. You may implement.

  Moreover, you may implement a 1st grinding | polishing process and a 2nd grinding | polishing process using a separate grinding | polishing apparatus. Furthermore, when using a polishing apparatus including a plurality of polishing pads, the first polishing step and the second polishing step may be polished using different types of polishing pads, or the first polishing step and the second polishing step may be performed. The same type of polishing pad may be used in the polishing step.

  The chemical mechanical polishing aqueous dispersion of the present embodiment uses, for example, a polishing pad containing a water-insoluble matrix material containing a crosslinked polymer and water-soluble particles dispersed in the water-insoluble matrix material. When polishing an object to be polished, it is possible to obtain both a better surface to be polished and a polishing rate, and in particular, it is possible to obtain a very good polishing rate when polishing a conductive barrier layer and an insulating layer. . In this case, the use of a crosslinked rubber such as crosslinked 1,2-polybutadiene as a water-insoluble matrix material in that it is possible to prevent settling and excessive wear and to maintain the polishing performance stably. A polishing pad using cyclodextrin as water-soluble particles is preferred. An example of such a polishing pad is a product number “FP8000” manufactured by JSR Corporation.

3. Examples Hereinafter, the present invention will be described by way of examples. However, the present invention is not limited to the examples. In this example, the average primary particle size and the average secondary particle size of the particles were measured by a laser diffraction method (measuring device: dynamic light scattering particle size distribution measuring device manufactured by HORIBA, Ltd., product number “HORIBA LB550”) ).

3.1. Preparation of aqueous dispersion containing inorganic particles 3.1.1. Preparation of Aqueous Dispersion Containing Fumed Silica Particles In 6 kg of ion-exchanged water, 6 kg of fumed silica (manufactured by Nippon Aerosil Co., Ltd., trade name “Aerosil # 90”) is mixed with a planetary kneader (trade name TK Habis Disper). Using a mix, HDM-3D-20 type, manufactured by Tokushu Kika Kogyo Co., Ltd.), a twist blade was continuously added over 30 minutes while rotating and kneading the main rotary shaft at 10 rpm and the sub rotary shaft at 30 rpm. Furthermore, a kneading operation for rotating the twist blade at a sub-rotating shaft of 30 rpm, a process for rotating the sub-rotating shaft of a coreless high-speed rotary blade having a diameter of 80 mm at 2000 rpm, and a process for rotating the main rotating shaft at 10 rpm are performed. Continued for hours.

  Thereafter, an aqueous dispersion obtained by adding 0.45 kg of a 20% by mass aqueous potassium hydroxide solution was diluted with ion-exchanged water to obtain an aqueous dispersion having a silica content of 30% by mass. This aqueous dispersion was filtered through a depth cartridge filter having a pore size of 5 μm to obtain an aqueous dispersion R3 containing fumed silica particles H1.

3.1.2. Preparation of aqueous dispersion containing colloidal silica particles 3.1.2a. Preparation of Aqueous Dispersion Containing Colloidal Silica Particle C1 Using colloidal silica particle C1 (manufactured by Fuso Chemical Industry Co., Ltd., model name “colloidal silica PL-3H”), water containing 25% by mass of colloidal silica particle C1 Dispersion S1 was prepared.

  The average primary particle diameter of the colloidal silica particles C1 contained in the aqueous dispersion S1 was 32 nm, the average secondary particle diameter was 83 nm, and the average degree of association was 2.6.

3.1.2b. Preparation of Water Dispersions S2 to S9, R1, and R2 Containing Colloidal Silica Particles C2 to C11, respectively According to the following methods, water dispersions S2 to S9, R1, and R2 containing colloidal silica particles C2 to C11 shown in Table 1 were respectively obtained. Prepared and used in Examples 2-9 and Comparative Examples 1 and 2, respectively.

  3 volumes of tetraethoxysilane and 1 volume of ethanol were mixed to obtain a raw material solution. A reaction solvent in which ethanol, water, and ammonia were mixed in advance was charged into the reaction vessel. The concentration of water in the reaction solvent was constant at 15% by weight, and the ammonia concentration was the value shown in Table 1, respectively. The ethanol concentration is the remaining value excluding water and ammonia. While cooling so that the temperature of the reaction solvent is maintained at 20 ° C., 1 volume of the raw material solution per 9 volumes of the reaction solvent is dropped into the reaction vessel at the dropping rate shown in the following table, and an alcohol dispersion of colloidal silica C2 to C11. Got.

  Subsequently, using a rotary evaporator, the operation of removing the alcohol while adding ion-exchanged water was repeated several times while maintaining the temperature of the obtained alcohol dispersion at 80 ° C. By this operation, aqueous dispersions S2 to S9, R1, and R2 containing 25% by mass of colloidal silica particles C2 to C11 were prepared.

3.2. Preparation of first aqueous dispersion for polishing and evaluation of polishing performance 3.2.1. Preparation of first aqueous dispersion for polishing 2 kg of fumed silica particles (manufactured by Nippon Aerosil Co., Ltd., trade name “Aerosil # 90”, average primary particle size 20 nm) in 6.7 kg of ion-exchanged water with an ultrasonic disperser Used to disperse. This was filtered with a filter having a pore size of 5 μm to obtain an aqueous dispersion containing 23% by mass of fumed silica particles. The average secondary particle diameter of the fumed silica particles contained in this aqueous dispersion was 220 nm.

An aqueous dispersion containing fumed silica particles in an amount corresponding to 1% by mass in terms of silica is put into a polyethylene bottle, and 0.5% by mass of quinaldic acid, 2, 4, 7, 9- 0.05% by mass of tetramethyl-5-decine-4,7-diol-dipolyoxyethylene ether (manufactured by Air Products Japan Ltd., trade name “Surfinol 465”) in terms of hydrogen peroxide is 0. 30 mass% hydrogen peroxide water corresponding to 1 mass% was sequentially added and stirred for 15 minutes. Thereafter, the pH was adjusted to 9.5 with a 1N aqueous potassium hydroxide solution, and then filtered through a filter having a pore size of 5 μm to obtain a first polishing aqueous dispersion.

3.2.2. Evaluation of Polishing Performance of First Aqueous Dispersion for Polishing A polishing pad made of polyurethane foam (made by Nitta Haas Co., product number “IC1000”) is applied to a chemical mechanical polishing apparatus (Applied Materials, model “Mirra”). Wearing and supplying the above chemical mechanical polishing aqueous dispersion, the following various polishing rate measurement substrates are subjected to chemical mechanical polishing for 1 minute under the following polishing conditions, and the polishing rate is calculated by the following method. did.

I. Polishing rate measurement substrate-Silicon substrate with 8-inch thermal oxide film on which a copper film with a film thickness of 15000 mm (corresponding to the metal layer of the present invention) was laminated (“15,000 mm wafer with copper film” manufactured by atdf)
A silicon substrate with an 8-inch thermal oxide film on which a tantalum nitride film having a thickness of 3000 mm (corresponding to the stopper layer (conductive barrier layer) of the present invention) is laminated (manufactured by Wafernet, “3000 wafer with tantalum nitride film”)
An 8-inch silicon substrate on which a BD film with a thickness of 10,000 mm (corresponding to the first insulating layer of the present invention) is laminated (“wafer with 10000 mm BD film” manufactured by atdf)
-An 8-inch silicon substrate on which a PETEOS film having a thickness of 10,000 mm (corresponding to the second insulating layer of the present invention) is laminated (“wafer with 10,000 mm TEOS film” manufactured by atdf)

II. Polishing conditions-Head rotation speed: 130 rpm
・ Platen rotation speed: 130rpm
Head load: 1.5 psi
-Supply rate of chemical mechanical polishing aqueous dispersion: 200 ml / min

III. Polishing speed calculation method For the copper film and the tantalum nitride film, the film thickness after the polishing treatment is measured using an electric conduction type film thickness measuring instrument (model OMNIMAP RS75, manufactured by KLA-Tencor Corporation), The polishing rate was calculated from the film thickness reduced by chemical mechanical polishing and the polishing time.

  For the PETEOS film, the film thickness after polishing treatment was measured using a light interference type film thickness measuring device (manufactured by Nanometrics Japan Co., Ltd., model “Nanospec6100”), and the film thickness decreased by chemical mechanical polishing. The polishing rate was calculated from the polishing time.

IV. Polishing rate-Polishing rate of metal layer (copper) (R _M ): 5500 Å / min-Polishing rate of conductive barrier layer (tantalum nitride layer) (R _B ): 30 Å / min-Polishing rate of insulating layer (PETEOS film) (R _In ): 40 Å / min

3.3. Example 1
3.3.1. Preparation of Second Polishing Aqueous Dispersion (Chemical Mechanical Polishing Aqueous Dispersion of the Present Invention) An aqueous dispersion containing the above “3.1.2a. Colloidal silica particles in an amount corresponding to 4% by mass in terms of silica. The aqueous dispersion containing the colloidal silica particles C1 prepared in “Preparation of” was put in a polyethylene bottle, and (E) a nonionic surfactant (2,4,7,9-tetramethyl-5-decyne- 4,7-diol-dipolyoxyethylene ether (n + m = 10) (product name “Surfinol 465” manufactured by Air Products Japan Co., Ltd.)), (B) pyridinecarboxylic acid (2,3-pyridinecarboxylic acid) , (C) Organic acid other than (B) (maleic acid), (D) oxidizing agent (30% by mass hydrogen peroxide in an amount corresponding to 0.3% by mass in terms of hydrogen peroxide) And stirred for 15 minutes. Thereafter, (H) 0.98% by mass of a pH adjuster (potassium hydroxide) was added to adjust the pH of the aqueous dispersion to 9.0. Next, ion-exchanged water was added so that the total amount of all the constituent components was 100% by mass, and then filtered through a filter having a pore diameter of 5 μm, thereby obtaining a second polishing aqueous dispersion S1. Table 2 shows the amount of each component in the second polishing aqueous dispersion S1.

3.3.2. Evaluation of polishing performance of second aqueous dispersion for polishing Water-soluble particles (β-polybutadiene) cross-linked with a chemical mechanical polishing apparatus (Applied Materials, model “Mirra”) -A cyclodextrin) -dispersed polishing pad (manufactured by JSR Co., Ltd., product number “FP8000”) was mounted on the following various polishing rate measurement substrates while supplying the chemical mechanical polishing aqueous dispersion. Chemical mechanical polishing was performed for 1 minute under the following polishing conditions, and the polishing rate was calculated by the following method.

I. Polishing speed measurement substrate ・ Silicon substrate with an 8-inch thermal oxide film on which a copper film having a film thickness of 15000 mm (corresponding to the metal layer of the present invention) is laminated ・ Tantalum nitride film having a film thickness of 2000 mm (stopper layer of the present invention (conductivity) Eight-inch silicon substrate with thermal oxide film laminated to the barrier layer) 8-inch silicon substrate laminated with a 10000 mm PETEOS film (corresponding to the second insulating layer of the present invention) Applied Materials Japan Co., Ltd. 8 inch silicon substrate on which a first insulating layer (BD film) with a film thickness of 4000 mm (relative dielectric constant k = 2.8) is laminated by a black diamond process developed by the company ・ MSQ type film developed by JSR Corporation 8-inch silicon substrate on which a first insulating layer (LKD film) (relative dielectric constant k = 2.3) having a thickness of 5000 mm is laminated

II. Polishing conditions-Head rotation speed: 130 rpm
・ Platen rotation speed: 130rpm
Head load: 1.5 psi
-Supply rate of chemical mechanical polishing aqueous dispersion: 200 ml / min

III. Polishing speed calculation method For the copper film and the tantalum nitride film, the film thickness after the polishing treatment is measured using an electric conduction type film thickness measuring instrument (model OMNIMAP RS75, manufactured by KLA-Tencor Corporation), The polishing rate was calculated from the film thickness reduced by chemical mechanical polishing and the polishing time.

  For the PETEOS film, BD film, and LKD film, the film thickness after the polishing treatment was measured using an optical interference film thickness measuring device (Nanometrics Japan Co., Ltd., model “Nanospec6100”), The polishing rate was calculated from the film thickness decreased by polishing and the polishing time.

IV. The rate of polishing speed and the metal layer (copper) _(R M): removal rate of 250 Å / min, conductive barrier layer (stopper layer (tantalum nitride _{layer)) (R B): 800Å} / min · second insulating layer ( PETEOS film) polishing rate (R _In-2 ): 380 Å / min ・ First insulating layer (BD film) polishing rate (R _In-1-1 ): 170 Å / min ・ First insulating layer (LKD film) Polishing rate (R _In-1-2 ): 190 Å / min

V. Evaluation Method of Number of Scratches of First Insulating Layer The presence or absence of peeling at the outer peripheral portion of the first insulating layer after polishing was observed visually and with an optical microscope. Further, using a pattern-less wafer defect inspection apparatus (manufactured by KLA-Tencor Corporation, model “KLA2351”), the number of defects per entire surface to be polished was measured, and the number of scratches was counted. The results are shown in Table 2 as “the number of scratches of the first insulating layer”. Of those counted as defects by the wafer defect inspection apparatus, those that are not scratched include, for example, adhering dust, stains generated during wafer manufacture, and the like.

In the above “V. Evaluation Method for Number of Scratches of First Insulating Layer”, inspection parameters of the defect inspection apparatus are shown below.
Inspection field: bright field Inspection wavelength: visible light Pixel size: 0.39
・ Threshold (defect detection sensitivity): 50

VI. Evaluation of dishing and scratch (i) Fabrication of substrate to be polished on which copper wiring is formed An insulating layer (PETEOS film (thickness 500 mm) having a pattern composed of a plurality of grooves having a depth of 1 μm is formed on the surface of a substrate made of silicon. ) And a BD film (composite film of 4500 mm thickness) were laminated by 5000 mm. Next, a conductive barrier layer (TaN film) having a thickness of 250 mm is formed on the surface of the insulating layer, and then a metal layer (Cu layer) having a thickness of 1.1 μm is formed by sputtering and plating in the groove covered with the TaN film. ) Was deposited.

(Ii) Evaluation after the first polishing step For the wafer prepared in (i) above, using the first polishing aqueous dispersion prepared in “3.2.1. Preparation of first polishing aqueous dispersion”. Polishing was performed at a polishing rate of 5500 mm for 2.25 minutes.

  After completion of the first polishing step, the dishing of the wiring having a width of 100 μm in the surface to be polished was evaluated using a stylus type step gauge (manufactured by KLA-Tencor Co., Ltd., model “HRP240”), and was 400 mm.

  Here, “dishing” is the distance (height difference) between the upper surface of the wafer (a plane formed by an insulating layer or a conductive barrier layer) and the lowest part of the wiring portion.

(Iii) Evaluation after the second polishing step The wafer prepared in the above (ii) was polished using the aqueous dispersions of Examples 1 to 9 and Comparative Examples 1 to 3 for the time calculated by the following formula.
Polishing time (min) = {(barrier layer thickness (Å)) ÷ (barrier layer (tantalum nitride) calculated in “3.3.2. Evaluation of polishing performance of second polishing aqueous dispersion” above) Polishing speed) + (thickness of first insulating layer (500 mm)) ÷ (first insulating layer (PETEOS) calculated in “3.3.2. Evaluation of polishing performance of second polishing aqueous dispersion”) Polishing speed} + (thickness of second insulating layer (200 mm)) ÷ (second insulating layer (BD) calculated in “3.3.2. Evaluation of polishing performance of second polishing aqueous dispersion” above) Polishing rate)}

About the surface to be polished, dishing of 100 μm wiring was evaluated using a stylus type step gauge (manufactured by KLA Tencor Co., Ltd., type “HRP240”). The results are shown in Table 2.

  Here, “dishing” is the distance (height difference) between the upper surface of the wafer (a plane formed by an insulating layer or a conductive barrier layer) and the lowest part of the wiring portion.

  In addition, a field region having no pattern (polishing amount of an insulating film in a field region wider than 120 μm × 120 μm is polished using an optical interference film thickness measuring device (manufactured by Nanometrics Japan Co., Ltd., model “Nanospec6100”). When the film thickness after the treatment was measured and calculated as the film thickness decreased from the initial film thickness of 5000 mm, it was 750 to 900 mm in each of Examples 1 to 5 and the aqueous dispersions of Comparative Examples 1 and 2.

  Further, using an optical microscope, in a dark field, the copper wiring portion was observed at 200 random locations with a region of 120 μm × 120 μm as a unit region, and the number of unit regions where the scratch was generated was determined as “Scratch of copper wiring”. Measured as "number". The results are shown in Table 2.

VII. Elastic Modulus of First Insulating Layer A Berkovich type indenter was attached to an ultra-small hardness meter (Nanoindentator XP) manufactured by MTS, and the elastic modulus of the first insulating layer was measured by a continuous stiffness measurement method. The results are shown below.
-Elastic modulus of the first insulating layer (BD film): 4.5 GPa
-Elastic modulus of the first insulating layer (LKD film): 3.0 GPa

3.4. Examples 2 to 9 and Comparative Examples 1 to 3
In Example 1, polishing was performed in the same manner as in Example 1 except that the types and amounts of each component of the chemical mechanical polishing aqueous dispersion, the pH of the aqueous dispersion, and the polishing pad used were as shown in Table 2. Was done. In addition, the polishing pad used in Examples 5 to 7 is a hard foam polyurethane polishing pad (made by Nita Haas Co., Ltd., product number “IC1000”), and the polishing pad used in Examples 8 and 9 is made of polyurethane. This is a polishing pad (product number “Politex” manufactured by Nitta Haas Co., Ltd.).

  That is, evaluation was performed in the same manner as in Example 1 except that each of the aqueous dispersions S2 to S9 and R1 to R3 synthesized above was used instead of S1 as the chemical mechanical polishing aqueous dispersion. The evaluation results are shown in Table 2.

  According to Table 2, when the chemical mechanical polishing aqueous dispersions of Examples 1 to 9 are used, when the insulating layer formed on the semiconductor substrate is chemically mechanically polished, the occurrence of scratches and dishing on the polished surface is greatly increased. In addition, the insulating layer can be sufficiently flattened without excessively polishing the insulating layer without significantly changing the relative dielectric constant of the insulating layer, and a highly accurate polished surface can be obtained. I found out.

  In contrast, when the chemical mechanical polishing aqueous dispersions of Comparative Examples 1 to 3 were used, dishing after polishing was large.

1, 2, 3 Wiring structure 1a, 2a, 3a Polishing object 11 Substrate (for example, silicon)
12 Insulating layer (for example, PETEOS film or insulating layer having a relative dielectric constant of 3.5 or less)
13 Stopper layer (for example, barrier layer)
14 Metal layer 20 Recess 21 First insulating layer (for example, an insulating layer having a relative dielectric constant of 3.5 or less)
22 2nd insulating layer 31 3rd insulating layer (for example, silicon oxide)
32 Fourth insulating layer (eg, silicon nitride)
112 Insulating layer

Claims (15)

A chemical mechanical polishing aqueous dispersion for polishing an insulating layer contained in a semiconductor device,
(A) Abrasive grain, (B) Quinoline carboxylic acid and / or pyridine carboxylic acid, (C) Aliphatic organic acid having 4 or more carbon atoms, (D) Oxidizing agent, (E) Nonionic surface activity having triple bond An agent, and (F) a dispersion medium,
The chemical mechanical polishing aqueous dispersion, wherein (A) the abrasive is colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.9 to 4.0.   2. The chemical mechanical polishing aqueous dispersion according to claim 1, wherein the oxidizing agent (D) is hydrogen peroxide. The chemical mechanical polishing aqueous dispersion according to claim 1 or 2, wherein the (E) nonionic surfactant is a compound represented by the following general formula (1).

(1)
(In the formula, n and m are each independently an integer of 1 or more and satisfy n + m ≦ 50.)   The ratio (B / E) of the blending amount of the (B) quinolinecarboxylic acid and / or pyridinecarboxylic acid to the blending amount of the (E) nonionic surfactant is 0.01 to 5. The chemical mechanical polishing aqueous dispersion according to claim 3. When the conductive barrier layer and the insulating layer are subjected to chemical mechanical polishing under the same conditions, the polishing rate ratio (R _B / _B ) between the polishing rate (R _B ) of the conductive barrier layer and the polishing rate (R _In-1 ) of the insulating layer. The aqueous dispersion for chemical mechanical polishing according to any one of claims 1 to 4, wherein RIn _-1 ) is 1.2 to 4.0. When each of the copper layer, the conductive barrier layer, the first insulating layer, and the second insulating layer having a dielectric constant higher than that of the first insulating layer is subjected to chemical mechanical polishing under the same conditions, the polishing rate (R _B) and the polishing rate of the copper layer _{(R M)} and the polishing rate ratio _(which is _R B / R _M) of 1.5 or more, the polishing rate of the second insulating layer _{(R an in-2)} and the copper layer The polishing rate ratio (R _In-2 / R _M ) to the polishing rate (R _M ) is 0.9 to 2.5, and the polishing rate (R _In-2 ) of the second insulating layer is 6. The polishing rate ratio (R _In−2 / R _In−1 ) to the polishing rate (R _In−1 ) of the first insulating layer is 0.5 to 5, 6. An aqueous dispersion for chemical mechanical polishing. Using a polishing pad containing a water-insoluble matrix material containing a crosslinked polymer and water-soluble particles dispersed in the water-insoluble matrix material, a copper layer, a conductive barrier layer, a first insulating layer, and When each of the second insulating layers having a dielectric constant higher than that of the first insulating layer is subjected to chemical mechanical polishing under the same conditions, the polishing rate of the first insulating layer (R _In-1 ), the polishing rate of the conductive barrier layer ( R _B ), the polishing rate of the copper layer (R _M ), and the polishing rate of the second insulating layer (R _In-2 ) satisfy R _In-2 > R _B > R _M > R _In−1 , The chemical mechanical polishing aqueous dispersion according to any one of claims 1 to 6. A first polishing step that is provided on the insulating layer having a recess via a stopper layer, and chemically and mechanically polishes the metal layer embedded in the recess until the stopper layer is exposed;
A second polishing step of chemically mechanically polishing the metal layer and the stopper layer until the insulating layer is exposed using the chemical mechanical polishing aqueous dispersion according to any one of claims 1 to 7. ,
A chemical mechanical polishing method comprising: The insulating layer includes a stack of a first insulating layer and a second insulating layer having a dielectric constant higher than that of the first insulating layer,
The chemical mechanical polishing method according to claim 8, wherein the second polishing step is a step of chemical mechanical polishing the metal layer, the stopper layer, and the second insulating layer.   The chemical mechanical polishing method according to claim 9, wherein a relative dielectric constant of the first insulating layer is 3.5 or less.   The chemical mechanical polishing method according to any one of claims 8 to 10, wherein the stopper layer is a conductive barrier layer. A kit for preparing the aqueous dispersion for chemical mechanical polishing according to any one of claims 1 to 7, comprising mixing the liquid (I) and the liquid (II),
The liquid (I) comprises (A) abrasive grains which are colloidal silica having an average primary particle size of 5 to 55 nm and an association degree of 1.9 to 4.0, (B) quinoline carboxylic acid and / or pyridine carboxylic acid, (C) an aqueous dispersion containing an aliphatic organic acid having 4 or more carbon atoms, (E) a nonionic surfactant having a triple bond, and (F) a dispersion medium,
The liquid (II) is a kit for preparing a chemical mechanical polishing aqueous dispersion containing (D) an oxidizing agent. A kit for preparing the aqueous dispersion for chemical mechanical polishing according to any one of claims 1 to 7, comprising mixing the liquid (I) and the liquid (II),
The liquid (I) is an aqueous dispersion containing (A) abrasive grains which are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.9 to 4.0, and (F) a dispersion medium,
The liquid (II) is (B) a quinoline carboxylic acid and / or pyridine carboxylic acid, (C) an aliphatic organic acid having 4 or more carbon atoms, (D) an oxidizing agent, and (E) a nonionic group having a triple bond. A kit for preparing a chemical mechanical polishing aqueous dispersion containing a surfactant. A kit for preparing an aqueous dispersion for chemical mechanical polishing according to any one of claims 1 to 7, wherein the liquid (I), the liquid (II), and the liquid (III) are mixed. And
The liquid (I) is an aqueous dispersion containing (A) abrasive grains which are colloidal silica having an average primary particle diameter of 5 to 55 nm and an association degree of 1.9 to 4.0, and (F) a dispersion medium,
The liquid (II) contains (B) a quinolinecarboxylic acid and / or pyridinecarboxylic acid and (E) a nonionic surfactant having a triple bond,
The liquid (III) is a kit for preparing a chemical mechanical polishing aqueous dispersion containing (D) an oxidizing agent.   The liquid (I) comprises (B) a quinoline carboxylic acid and / or pyridine carboxylic acid, (C) an aliphatic organic acid having 4 or more carbon atoms, (D) an oxidizing agent, and (E) a nonionic group having a triple bond. The kit for preparing the chemical mechanical polishing aqueous dispersion according to claim 13 or 14, further comprising one or more components selected from surfactants.

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