JP2009065041A - Composition for chemical mechanical polishing containing fine fiber cellulose and/or its complex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for chemical mechanical polishing which reduces occurrence of defects of a polishing surface by improving dispersion property and providing chelate capability. <P>SOLUTION: The composition for chemical mechaninical polishing contains 0.01 to 3 wt.% of fine fiber cellulose having a 0.5 μm to 1 mm length (major radius), a 2 nm to 60 μm width (minor radius) and a 5-400 ratio of length to width (major radius to minor radius). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a chemical mechanical polishing composition. The chemical mechanical polishing composition is used, for example, for planarization of a semiconductor wafer.

In recent years, integrated circuits in semiconductor manufacturing processes are increasingly required to be miniaturized and multilayered. Multi-layered wiring of semiconductor large-scale integrated circuits is a factor that increases the unevenness of semiconductors. This, combined with miniaturization of integrated circuits, leads to disconnection, lowering of electric capacity, occurrence of electromigration, etc., causing problems such as lowering of yield. Cause.
For this reason, various processing techniques for flattening metal wiring and interlayer insulating films in a multilayer wiring board have been developed so far, and one of them is CMP (Chemical Mechanical).
Polishing (chemical mechanical polishing) technology. The CMP technique is a technique necessary for planarizing (mirroring) an interlayer insulating film, forming a buried wiring, forming a plug, and the like in semiconductor manufacturing. CMP is performed by rotating the carrier and the polishing pad while pressing a flat wafer made of a normal semiconductor mounted on the carrier against the wet polishing pad with a constant pressure. At this time, the convex portions of the wiring and the insulating film are polished by the polishing composition introduced between the wafer and the polishing pad, and flattening (mirror finishing) is performed.

  Conventionally, various polishing compositions and polishing methods have been proposed for polishing a metal film of a semiconductor substrate. As shown in “Semiconductor flattening CMP technology” by Toshiro Tohi et al. (July 1998, Industrial Research Committee), page 235, metal CMP oxidizes the metal surface with an oxidizing agent in the abrasive composition. However, polishing is performed with a polishing pad and abrasive grains under conditions where the metal is corroded and the pH is acidified and the metal is slightly corroded (etching). For example, as a polishing composition for a metal film such as aluminum formed on a semiconductor substrate, a polishing composition in which aluminum oxide is dispersed in an aqueous nitric acid solution having a pH of 3 or less (Patent Document 1), aluminum oxide or silicon oxide is sulfuric acid. There exists polishing composition (patent document 2) formed by mixing with acidic aqueous solution, such as nitric acid and acetic acid. Further, a polishing composition comprising an abrasive such as silicon oxide or aluminum oxide and an oxidizing agent such as hydrogen peroxide, such as a polishing composition in which aluminum oxide is dispersed in hydrogen peroxide and an aqueous phosphoric acid solution (Patent Document 3). Usually used. However, a polishing composition in which an abrasive made of a metal oxide such as silicon oxide or aluminum oxide is dispersed in an aqueous solution has a problem of surface scratches due to poor dispersibility of the abrasive itself.

In addition, when hydrogen peroxide is used as described above, or when a metal etchant such as ammonium persulfate is used (Patent Document 4), pits and voids are generated due to excessive progress of wet etching, There was a problem in practical use. In order to improve this, a method of adding a chemical reagent (chelating agent or the like) that forms a protective film on the surface of the metal film in the polishing composition has also been proposed (Patent Documents 5 and 6).
However, when such a chelating agent is used, etching is surely suppressed and the generation of pits and voids can be prevented. However, since a protective film is also formed on the portion to be polished, the polishing rate is remarkably reduced. Etc. occur. In addition, a proposal has been made to use polyoxoacids in combination with a nonionic surfactant and an anionic surfactant (Patent Document 7). However, the storage stability was still not sufficient.

In addition, a slurry (slurry) in which a polishing agent made of silicon oxide, particularly colloidal silica, etc. in a wafer polishing step is diluted with water and further added with alkali is used.
At this time, various amines are added in order to increase the polishing rate (Patent Document 8).
However, since these polishing compositions have insufficient dispersibility of the abrasive grains themselves, the polishing rate must be increased. However, metal contamination into the wafer due to the use of amine, such as copper contamination, is typically required. There is a problem (that is, since the amine itself has an effect of capturing copper (chelating effect), the use of this amine results in a problem of contaminating the wafer with copper), and the solution has not been sufficient. In devices that use wafers, copper is exclusively used as the wiring material, so it is important to prevent copper contamination for the regeneration of the wafers, but amines and ammonia are used as alkali components in the chemical mechanical polishing process. When the slurry is contaminated with copper, many cases of copper contamination on the wafer have been reported.

U.S. Pat. No. 4,702,792 U.S. Pat. No. 4,944,836 US Pat. No. 5,209,816 JP-A-6-313164 JP-A-8-83780 JP-A-11-195628 JP 2004-189894 A JP 2002-105440 A

  The present invention relates to a chemical mechanical polishing composition. The chemical mechanical polishing composition is used, for example, for planarization (mirroring) of a wafer made of semiconductor, and aims to improve the dispersibility of a conventional chemical mechanical polishing composition and to have chelating ability. Is.

  As a result of intensive studies to solve the above problems, the present inventors have found that fine fibrous cellulose having a specific size, or fine fibers comprising the fine fibrous cellulose and a water-soluble polymer and / or a hydrophilic substance. By using a chemical mechanical polishing composition containing 0.01 to 3% by mass of a cellular cellulose composite, the dispersibility of a conventional chemical mechanical polishing composition is improved and the chelating ability is suppressed, thereby further improving the polishing surface. The inventors have found that defects can be suppressed and have completed the present invention.

That is, the present invention is as follows.
1. 0.01 to 3% by mass of fine fibrous cellulose having a length (major axis) of 0.5 μm to 1 mm, a width (minor axis) of 2 nm to 60 μm, and a length to width ratio (major axis / minor axis) of 5 to 400 A chemical mechanical polishing composition comprising:
2. 1. A surfactant is contained in an amount of 0.01 to 40% by mass. The composition for chemical mechanical polishing described in 1.
3. The fine fibrous cellulose is a fine fibrous cellulose composite composed of fine fibrous cellulose and a water-soluble polymer. Or 2. The composition for chemical mechanical polishing described in 1.

  The chemical mechanical polishing composition of the present invention is used, for example, for planarization (mirroring) of a wafer made of a semiconductor, improves the dispersibility of a conventional chemical mechanical polishing composition, and has a chelating ability. It is possible to further suppress defects on the polished surface.

Hereinafter, the present invention will be specifically described focusing on its preferred form. The chemical mechanical polishing composition of the present invention is a slurry in which 0.1 to 30% by mass, preferably 1.0 to 15% by mass of an abrasive is dispersed in water or a mixed solvent of water and an organic solvent. In the composition, fine fibrous cellulose having a length (major axis) of 0.5 μm to 1 mm, a width (minor axis) of 2 nm to 60 μm, and a ratio of length to width (major axis / minor axis) of 5 to 400 is 0.00. It is a chemical mechanical polishing composition containing 0.1 to 3% by mass.
The fine fibrous cellulose of the present invention is obtained by wet-pulverizing a cellulosic material originating from the plant cell wall to make short fibers, and using a high-pressure homogenizer, the length (major axis) is 0.5 μm to 1 mm, and the width (minor axis). Is a cellulosic material highly refined to 2 to 60 μm and the ratio of length to width (major axis / minor axis) of 5 to 400. By making the cellulosic material into a fine fiber in this way, the entanglement between molecules and the network structure are strengthened, exhibiting a higher viscosity at a lower concentration than ordinary crystalline cellulose, and preventing sedimentation of coarser particles. In addition, the properties unique to fine fibrous cellulose such as rough and sticky feeling are expressed.
The fine fibrous cellulose composite of the present invention is a water-dispersible cellulose obtained by blending the fine fibrous cellulose and a water-soluble polymer, and its production method is disclosed in the examples described later, and other An example is JP-A-2004-41119.

  The water-soluble polymer used in the present invention is a polymer that dissolves or swells in cold water and / or warm water, and has a function of preventing keratinization between celluloses during drying. Specifically, gum arabic, arabinogalactan, alginic acid and its salts, curdlan, gutty gum, carrageenan, caraya gum, agar, xanthan gum, guar gum, enzymatic degradation guar gum, quince seed gum, gellan gum, gelatin, tamarind seed gum, indigestible 1 or 2 selected from water-soluble dextrin, tragacanth gum, fercellan, pullulan, pectin, polydextrose, locust bean gum, water-soluble soybean polysaccharide, carboxymethylcellulose, metal salt of carboxymethylcellulose, methylcellulose, sodium polyacrylate, etc. More than seed material is used. Of these, sodium carboxymethylcellulose and sodium are preferred.

In the present invention, a fine fibrous cellulose composite may be obtained by further adding a water-soluble substance to fine fibrous cellulose and a water-soluble polymer. The water-soluble substance used in the present invention is a substance that is highly soluble in cold water and hardly causes viscosity, and is a solid substance at room temperature. For example, dextrins, water-soluble saccharides (glucose, fructose, sucrose, lactose, Isomerization, etc., xylose, trehalose, raffinose, coupling sugar, palatinose, sorbose, reduced starch saccharified starch, maltose, lactulose, fructooligosaccharide, galactooligosaccharide, xylooligosaccharide, cellooligosaccharide, gentiooligosaccharide, etc.), sugar alcohols (xylitol, Or one or more substances selected from maltitol, mannitol, sorbitol and the like.
In the present invention, it is easier to obtain better results when the fine fibrous cellulose is preliminarily used as the composite. Since composites tend to be superior in all respects such as water dispersibility, stability, and feel, for example, due to problems in manufacturing equipment, concerns about supply of raw materials, and legal regulations of each country / local government. Unless there is a special reason that the complex cannot be used, it is preferable to use it as a complex.

  In order to produce the chemical mechanical polishing composition of the present invention, when the fine fibrous cellulose and / or composite thereof is added, the fine fibrous cellulose and / or composite thereof may be used alone, or galactomannan, glucomannan. One or more water-soluble gums selected from xanthan gum and locust bean gum may be combined. In this case, the ratio of the fine fibrous cellulose and / or the composite thereof to one or more water-soluble gums selected from galactomannan, glucomannan, xanthan gum and locust bean gum is fine fibrous cellulose: galactomannan, glucomannan, One or more water-soluble gums selected from xanthan gum and locust bean gum are preferably 10:90 to 90: 10% by mass. More preferably, it is 20: 80-70: 30 mass%.

Galactomannan is a polysaccharide having a structure composed of a main chain in which β-D-mannose is β-1,4 bonded and a side chain in which α-D-galactose is α-1,6 bonded. Examples of galactomannans include guar gum, locust bean gum, tara gum, etc. The ratio of mannose to glucose is about 2: 1 for guar gum, about 4: 1 for locust bean gum, and about 3: 1 for tara gum.
Glucomannan is a polysaccharide having a structure in which D-glucose and D-mannose are linked by β-1,4, and the ratio of glucose to mannose is about 2: 3. Since there is a unique irritating odor when the degree of purification is low, it is preferable to use one with a high degree of purification.

  Xanthan gum is produced by fermenting starch such as corn with the bacterium Xanthomonas campestris, and has a molecular weight of about 2 million or 13 to 50 million. It is said to consist of repeating units of 2 glucose molecules, 2 mannose molecules, and glucuronic acid. Xanthan gum also includes potassium, sodium and calcium salts.

  The addition amount of the fine fibrous cellulose and / or the composite is preferably 0.01 to 3% by mass. More preferably, it is 0.05-2 mass%, More preferably, it is 0.1-1 mass%. When the amount of the fine fibrous cellulose and / or composite thereof is less than 0.01% by mass, there is a possibility that sedimentation, separation, consolidation, etc. of the components will occur in the chemical mechanical polishing composition over time. is there. When the addition amount of fine fibrous cellulose and / or a composite thereof exceeds 3% by mass, the viscosity of the chemical mechanical polishing composition may become too high.

The surfactant referred to in the present invention may be any of anionic type, cationic type, nonionic type, natural type, and high molecular type. For example, phospholipid, lecithin, lanolin, cholesterol, saponin, sucrose fatty acid ester, alkyl sulfate ester Salt, polyoxyethylene aralkyl ether sulfate, acyl N-methyltaurine salt, alkyl ether phosphate ester salt, N-acyl amino acid salt, alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, benzalkonium chloride, alkyldimethylaminoacetic acid betaine , Alkylamidopropyldimethylaminoacetic acid betaine, polyoxyethylene type nonionic surfactants such as polyoxyethylene synthetic alcohol ether, polyhydric alcohol ester type nonionic surfactants, ethylene oxide propylene Such Kishido copolymer.
The chemical mechanical polishing composition of the present invention is finally used as a slurry by using water or a mixed solvent of water and an organic solvent as a solvent. However, as a general method of use, 0.01 to 3% by mass of fine fibrous cellulose having a specific size and / or its cellulose composite, which is characteristic in the present invention, and at least one surfactant is used. The chemical mechanical polishing composition contained above may be contained in a polishing liquid containing various chemical components, or may be contained in a slurry containing a hard fine abrasive.

In the chemical mechanical polishing composition of the present invention, the abrasive is not particularly limited. For example, silicon oxide (including colloidal silica), aluminum oxide, diamond, cubic boron, silicon carbide, phosphovanadmolybdic acid, etc. Or a mixture thereof. These metal powders can be used alone or in combination or as a mixed powder. The average particle diameter of the abrasive powder is not particularly limited according to the application and purpose.
If necessary, alcohols such as methanol, ethanol, n-butanol, iso-butanol, tertiary butanol, glycerin, and ethylene glycol can be added to the chemical mechanical polishing composition of the present invention. In addition, known inorganic acids such as sulfuric acid, phosphoric acid, nitric acid and the like, or known organic acids such as malic acid, citric acid, oxalic acid and acetic acid can also be used.

The chemical mechanical polishing composition of the present invention can be produced by a known method, for example, by the following method.
0.01-3 mass% of fine fibrous cellulose having a specific size and / or its composite
And a chemical mechanical polishing composition containing at least one surfactant and other components as described above using a stirrer, a kneader such as a homogenizer or kneader, a crusher, or the like. it can.
Further, particularly in an aqueous medium composed of water or a mixed medium of water and an organic solvent, 0.01 to 3% by mass of a fine fibrous cellulose having a specific size and / or a composite thereof, and at least a surfactant. A slurry liquid can be manufactured by mixing and stirring the chemical mechanical polishing composition and abrasive powder contained in one or more kinds.
Hereinafter, the present invention will be described more specifically using examples and the like, but the present invention is not limited to these examples and the like.

<Average polymerization degree of raw material (cellulosic substance)>
ASTM Designation: D 1795-90 “Standard Test Method for Intrinsic Visibility of Cellulose”.
<Α-cellulose content of raw material (cellulose)>
The test is carried out according to JIS P8101-1976 (“dissolving pulp test method” 5.5 α-cellulose).

<Shape of cellulose fiber (particle) (major axis, minor axis, major axis / minor axis ratio)>
Since the range of the size of cellulose fibers (particles) is wide, it is impossible to observe all with one kind of microscope. Therefore, an optical microscope and a scanning microscope (medium resolution SEM, high resolution SEM) are appropriately selected according to the size of the fibers (particles), and observed and measured. When using an optical microscope, the sample aqueous dispersion adjusted to an appropriate concentration is placed on a slide glass, and further a cover glass is placed on the glass for observation. When using a medium resolution SEM (JSM-5510LV, manufactured by JEOL Ltd.), a sample water dispersion is placed on a sample stage and air-dried, and then Pt—Pd is deposited by about 3 nm for observation.
When using a high-resolution SEM (S-5000, manufactured by Hitachi Science Systems, Ltd.), a sample aqueous dispersion is placed on a sample stage and air-dried, and then Pt—Pd is deposited by about 1.5 nm for observation.
The major axis, minor axis, and major axis / minor axis ratio of cellulose fibers (particles) were measured by selecting 15 (pieces) or more from the photographed photographs. Some fibers were almost straight and curved like hair, but never round like lint. The minor axis (thickness) was varied among single fibers, but an average value was adopted. A high-resolution SEM was used when observing a fiber having a minor axis of several nm to 200 nm, but one fiber was too long to fit in one field of view. Therefore, photography was repeated while moving the field of view, and then the pictures were synthesized and analyzed.

<Loss tangent (= loss elastic modulus / storage elastic modulus)>
(1) A sample and water are weighed so that it may become a 0.5% aqueous dispersion, and it disperse | distributes for 15 minutes at 15000 rpm with an ace homogenizer (Nippon Seiki Co., Ltd. make, AM-T type).
(2) Leave in an atmosphere at 25 ° C. for 3 hours.
(3) After putting the sample solution into the dynamic viscoelasticity measuring apparatus, the sample solution is allowed to stand for 5 minutes and then measured under the following conditions to determine a loss tangent (tan δ) at a frequency of 10 rad / s.
Equipment: ARES (100FRTN1 type)
(Rheometric Scientific, Inc.)
Geometry: Double Wall Couette
Temperature: 25 ° C
Distortion: 10%
Frequency: 1 → 100 rad / s (increased over about 170 seconds)

<0.25% viscosity>
(1) The sample and water are weighed so as to obtain an aqueous dispersion having a solid content concentration of 0.25%, and dispersed with an Excel auto homogenizer (ED-7 type, manufactured by Nippon Seiki Co., Ltd.) at 15000 rpm for 15 minutes.
(2) Leave in an atmosphere at 25 ° C. for 3 hours.
(3) After thoroughly stirring, set a rotational viscometer (Tokimec Co., Ltd., B type viscose, BL type), start rotation of the rotor 30 seconds after the end of stirring, and then increase the viscosity from the indicated value after 30 seconds. Is calculated. The rotor speed is 60 rpm, and the rotor is appropriately changed depending on the viscosity.

<Content of “component that is stably suspended in water”>
(1) The sample and water are weighed so as to obtain an aqueous dispersion having a cellulose concentration of 0.1%, and dispersed with an Excel auto homogenizer (ED-7 type, manufactured by Nippon Seiki Co., Ltd.) at 15000 rpm for 15 minutes.
(2) Put 20 g of sample solution into a centrifuge tube and centrifuge at 1000 G for 5 minutes in a centrifuge.
(3) The upper liquid portion is removed and the weight (a) of the sediment component is measured.
(4) Next, the sediment component is absolutely dried, and the weight (b) of the solid content is measured.
(5) The content (c) of the “component that is stably suspended in water” is calculated using the following formula.
c = 5000 × (k1 + k2) [%]

When the sample does not contain a water-soluble polymer (and a hydrophilic substance), k1 and k2 are calculated using the following formula and used.
k1 = 0.02-b
k2 = {k1 × (ab)} / (19.98−a + b)
Moreover, when a sample contains water-soluble polymer (and hydrophilic substance), k1 and k2 are used using the following formula.
k1 = 0.02−b + s2
k2 = k1 × w2 / w1
Cellulose / water-soluble polymer (hydrophilic substance) = f / d [blending ratio]
w1 = 19.98−a + b−0.02 × d / f
w2 = a−b
s2 = 0.02 * d * w2 / {f * (w1 + W2)}

When the content of “a component that is stably suspended in water” is very large, the weight of the sediment component becomes a small value, so that the measurement accuracy is lowered by the above method. In that case, the procedure after (3) is performed as follows.
(3 ′) Obtain the liquid portion of the upper layer and measure the weight (a ′).
(4 ′) Next, the upper layer portion is completely dried, and the weight (b ′) of the solid content is measured.
(5 ′) The content (c) of “a component that is stably suspended in water” is calculated using the following formula.
c = 5000 × (k1 + k2) [%]

When the sample does not contain a water-soluble polymer (and a hydrophilic substance), k1 and k2 are calculated using the following formula and used.
k1 = b ′
k2 = k1 × (19.98−a ′ + b ′) / (a′−b ′)
When the sample contains a hydrophilic polymer (and a hydrophilic substance), k1 and k2 are calculated using the following formula and used.
k1 = b′−s2 × w1 / w2
k2 = k1 × w2 / w1
Cellulose / hydrophilic substance (water-soluble substance) = f / d [compounding ratio]
w1 = a'-b '
w2 = 19.98−a ′ + b′−0.02 × d / f
s2 = 0.02 × d × w2 / {f × (w1 + w2)}
If the boundary between the upper liquid part and the sediment component is not clear and difficult to separate by the operation (3 ′), the upper 1/3 amount (about 7 g) of the whole is obtained, and thereafter (4 ′), ( Operate according to 5 ').

[Production Example 1]
Preparation of fine fibrous cellulose composite A; commercially available bagasse pulp (average polymerization degree = 1320, α-cellulose content = 77%) was cut into a 6 × 16 mm square. Next, each water was weighed out so that the concentration of commercially available bagasse pulp was 3 mass% and the concentration of sodium carboxymethylcellulose was 0.176 mass%, and the mixture was stirred for 5 minutes with a home mixer. This aqueous dispersion was treated three times with a grindstone rotary grinder (“Serendipeater” MKCA-6-3 type, grinder: MKE6-46, grinder rotational speed 1800 rpm). The sedimentation volume of the obtained aqueous dispersion was 100%.

  Next, the obtained aqueous dispersion was diluted with water to 2% by mass, passed through a high-pressure homogenizer (“microfluidizer” M-140K type, treatment pressure 110 MPa) for 4 passes, and an aqueous dispersion of fine fibrous cellulose. A was obtained. The degree of crystallinity was 73% or more. The 0.25% viscosity was 120 mPa · s. When observed with an optical microscope and medium resolution SEM, fine fibrous cellulose having a major axis of 10 to 500 μm, a minor axis of 1 to 25 μm, and a major axis / minor axis ratio of 5 to 190 was observed. The loss tangent was 0.32. The “component stably suspended in water” was 99% by mass.

  Add carboxymethylcellulose sodium and dextrin to aqueous dispersion A so that the solid content is cellulose: carboxymethylcellulose sodium: dextrin = 70: 18: 12 (parts by mass), and stir for 15 minutes with a stirring homogenizer. Mixed. This is dried with a drum dryer, scraped off with a scraper, and the resulting product is pulverized with a cutter mill (“Flush Mill” manufactured by Fuji Powder Co., Ltd.) through a sieve with 2 mm openings to make fine fibers A cellular cellulose composite A was obtained. The fine fibrous cellulose had a degree of crystallinity of 66%, a 0.25% viscosity of 143 mPa · s, a loss tangent of 0.38, and a “component stably suspended in water” of 98% by mass. Observation of “components that are stably suspended in water” with a high-resolution SEM reveals very fine fibrous cellulose having a major axis of 1 to 17 μm, a minor axis of 10 to 350 nm, and a major axis / minor axis ratio of 20 to 250. It was done.

[Production Example 2]
Adjustment of fine fibrous cellulose composite B; commercially available straw pulp (average polymerization degree = 930, α-cellulose content = 68% by mass) was cut into a 6 × 12 mm square, and the commercially available straw pulp concentration was 4% by mass. Then, water was added and stirred with a home mixer for 5 minutes. This was dispersed for 1 hour with a high-speed rotation type homogenizer (Yamato Scientific, “ULTRA-DISPERSER”). This aqueous dispersion was treated with a grindstone rotary grinder (grinder rotation speed: 1800 rpm). The number of treatments was 2, and the grinder clearance was changed from 60 to 40 μm. Next, the obtained aqueous dispersion was diluted with water to 2% by mass, and subjected to 8 passes with a high-pressure homogenizer (treatment pressure: 175 MPa) to obtain a water-dispersible cellulose B slurry. The crystallinity was 74%. When the secondary particles were observed with an optical microscope, fine fibrous cellulose having a major axis of 10 to 700 μm, a minor axis of 1 to 30 μm, and a major axis / minor axis ratio of 10 to 150 was observed. The loss tangent was 0.43. The content of “a component that is stably suspended in water” was 89% by mass. When the primary particles were observed with a high-resolution SEM, the major axis was 1-20 μm and the minor axis was 6-3.
A very fine fibrous cellulose having a length of 00 nm and a major axis / minor axis ratio of 30 to 350 was observed.

  Add carboxymethylcellulose sodium to the fine fibrous cellulose obtained by the above operation so that the fine fibrous cellulose and carboxymethylcellulose sodium are in a mass ratio of 85:15 as solid content, and stir The mixture was stirred and mixed for 15 minutes with a homogenizer. Subsequently, it dried with the drum dryer and scraped off with the scraper. This was pulverized with a cutter mill (manufactured by Fuji Powder Co., Ltd.) to almost pass through a sieve having an opening of 1 mm to obtain a fine fibrous cellulose composite B.

The degree of crystallinity of the fine fibrous cellulose composite B was 68% or more, the loss tangent was 0.51, and the content of the “component stably suspended in water” was 75% by mass. When this was observed with a high-resolution SEM, very fine fibrous cellulose having a major axis of 1 to 20 μm, a minor axis of 10 to 300 nm, and a major axis / minor axis ratio of 30 to 350 was observed.
Further, a chemical mechanical polishing composition was prepared as follows. In addition, dispersion | distribution of the fine fibrous cellulose composite was disperse | distributed for 5 minutes at 15000 rpm with the Excel auto homogenizer (The Nippon Seiki Co., Ltd. make, ED-7 type | mold).

[Example 1]
Phosphovanadomolybdic acid: 12 g of PVMo (trade name PVM-1-11 manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) was dissolved in 176 g of water, and stirred with a homogenizer. To this, polyoxyethylene synthetic alcohol ether as a nonionic surfactant was added: SF-1 (Brand name BLAUNON
After adding 8 g of DAL-5 (manufactured by Aoki Yushi Kogyo Co., Ltd.), 4 g of dodecylbenzenesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) is added as an anionic surfactant, and finally 1.0 g of Production Example 1 is added. Added.
[Example 2]
It was produced in the same manner as in Example 1, and finally, the product in Production Example 1 was not added, but 1.0 g of the product in Production Example 2 was added instead.

[Example 3]
After making a slurry containing 2.5% by weight of silicon oxide having an average particle size of 50 nm in water, 0.008 mol of N- (β-aminoethyl) ethanolamine is added per liter of the slurry, and a nonionic surfactant is added thereto. Polyoxyethylene synthetic alcohol ether: SF-1 (trade name BLAUNON DAL-5, Aoki Yushi Kogyo Co., Ltd.) is added so as to be 1% by weight, and finally the product in Production Example 1 is 0.3. The pH was adjusted to 11 by inclusion by weight.

[Example 4]
After making a slurry containing 2.5% by weight of silicon oxide having an average particle size of 50 nm in water, 0.008 mol of N- (β-aminoethyl) ethanolamine was added per liter of the slurry. The preparation was incorporated at 0.3% by weight and the pH was adjusted to 11.

[Comparative Example 1]
A composition was obtained in exactly the same manner as in Example 1 except that the product in Production Example 1 was not added.
[Comparative Example 2]
A composition was obtained in exactly the same manner as in Comparative Example 1, except that the nonionic surfactant SF-1 was not used.
[Comparative Example 3]
A composition was obtained in the same manner as in Example 4 except that the product in Production Example 1 was not added.

The evaluation means about each polishing composition of Examples 1-4 of this invention and Comparative Examples 1-3 are as follows.
(Polishing rate measurement; Examples 1 and 2, Comparative Examples 1 and 2)
The change in each film thickness before and after polishing was calculated by dividing by the polishing time. The polishing conditions are: polishing pressure 50 g / cm ² , relative speed between substrate and polishing pad 50 m / min, IC1400A21 (manufactured by Nitta Haas) dressed with a number 100 dresser as the polishing pad, and the polishing pad A silicon wafer with a copper film (thickness: 1 μm) was polished while dropping the chemical mechanical polishing composition.

(Polishing rate measurement; Example 3, Example 4, Comparative Example 3)
A silicon wafer having a diameter of 150 nm that was subjected to an etching process in a general wafer manufacturing process was polished. As mirror polishing conditions, IC1400A21 (manufactured by Nitta Haas) was dressed with a 100th dresser as a polishing pad, and the chemical mechanical polishing composition was dropped onto the polishing pad.
(Surface defect (scratch evaluation))
After the polished silicon wafer was washed and dried, a spotlight was applied to the surface of the semiconductor wafer in a dark room, and the presence or absence of scratches was visually determined.

(Dishing performance evaluation by etching rate measurement)
By evaluating the wet etching property, which is the cause of dishing, an alternative evaluation of dishing property was made. Since dishing is caused by erosion of the metal film due to excessive chemical action (wet etching) of the abrasive composition, the etching rate of the abrasive composition, which is the main cause of dishing, is reduced. By evaluating here, the dishing characteristic was evaluated as a result. Specifically, a silicon wafer with a copper film (thickness: 1 μm) is immersed and shaken in the polishing composition for 1 hour, the change in film thickness before and after immersion is measured, and the etching rate is obtained by dividing this by the immersion time. The dishing characteristics were evaluated according to the following criteria (◎ to ×). The slower the etching rate, the weaker the wet etching property and the less likely dishing occurs.
A: Etching rate less than 3 nm / min B: Etching rate 3-10 nm / min Δ: Etching rate 10-50 nm / min
×: Etching rate 50 nm / over

(Storage stability of chemical mechanical polishing composition)
As the storage stability evaluation of the chemical mechanical polishing composition after standing at 40 ° C. for 3 months, the following determination was made.
○: Change rate of polishing rate and etching rate is less than 5% Δ: Change rate of polishing rate and etching rate is 5% or more and less than 20% ×: Change rate of polishing rate and etching rate is 20% or more

(Measurement of copper on the surface of silicone wafers)
The state of metal contamination in the wafer due to the use of amine was measured by using the representative copper (Cu) as a scale to measure the surface copper (Cu) concentration. The amount of copper was evaluated by VPD-AAS (Vapor Phase Decomposition and Atomic Absorption Spectroscopy).
Table 1 shows the evaluation results of the polishing rate relative value, scratch evaluation, dishing evaluation, and storage stability of each of the polishing compositions of Example 1, Example 2, Comparative Example 1, and Comparative Example 2.
Table 2 shows the polishing rate relative value, scratch evaluation, and surface copper (Cu) concentration of each of the polishing compositions of Examples 3 and 4 and Comparative Example 3.

  The chemical mechanical polishing composition of the present invention is suitable for use in, for example, planarization of a wafer made of a semiconductor due to its dispersion force and chelate suppressing action.

Claims (3)

  0.01 to 3% by mass of fine fibrous cellulose having a length (major axis) of 0.5 μm to 1 mm, a width (minor axis) of 2 nm to 60 μm, and a length to width ratio (major axis / minor axis) of 5 to 400 A chemical mechanical polishing composition comprising:   The chemical mechanical polishing composition according to claim 1, comprising 0.01 to 40% by mass of a surfactant.   The composition for chemical mechanical polishing according to claim 1 or 2, wherein the fine fibrous cellulose is a fine fibrous cellulose composite comprising fine fibrous cellulose and a water-soluble polymer.