TWI400142B - Mutual invasive macromolecular reticular construct, grinding pad, and the preparing method thereof - Google Patents

Description

Mutual invasion of polymer mesh structure and polishing pad and its preparation method

The present invention relates to a method of producing a mutually invading polymer mesh structure. Further, the present invention relates to a polishing pad and a method of manufacturing the same. In particular, there is a polishing pad for planarizing an insulating layer surface or a metal wiring surface formed on a semiconductor substrate such as germanium.

Patent Document 1 discloses a polishing pad comprising a polymer obtained by polymerizing a polyurethane and a vinyl compound. Further, Patent Document 2 discloses a method for producing a polishing pad, which comprises a process for immersing a polymer molded body in a solution containing a polymerization monomer and then subjecting the monomer to a polymerization reaction.

However, in the conventional polishing pad, since the variation in characteristics between the pad and the pad is large, the in-plane uniformity of the polishing rate at the time of polishing is insufficient. Moreover, since the strength of the polishing pad is low, there is a problem that the pad is worn quickly and the durability of the pad is short during polishing.

Further, in the production of these polishing pads, there is a problem that the immersion speed of immersing the monomer in the polymer molded body is slow, and the time required for production becomes long. In order to avoid such an increase in viscosity, it is necessary to set a lower impregnation temperature, which must be impregnated for a long time due to low temperature impregnation. Further, since the organic solvent is added to the monomer for polymerization, the immersion rate does not decrease drastically even if the viscosity is increased. However, after the completion of the polymerization, a process for removing an unnecessary organic solvent is required.

Patent Document 1: WO00/122621 Patent Document 2: JP-A-2000-218551

An object of the present invention is to provide a mutually invading polymer mesh structure having excellent uniformity characteristics and high production efficiency, and a method for producing the same. Further, an object of the present invention is to provide a polishing pad having a high in-plane uniformity of polishing rate during polishing, capable of eliminating step differences in a short period of time, and having good planarization characteristics, and capable of reducing polishing pad The difference in the polishing characteristics between the two, the durability of the polishing is improved, and the manufacturing efficiency is high.

In order to solve the above problems, the constitution of the present invention is as follows.

(1) A method for producing a mutually invading polymer mesh structure, comprising a method for producing a mutually invading polymer mesh structure comprising an immersion process and a polymerization process, the dipping process comprising an ethylenically unsaturated compound and a radical polymerization initiation reaction The radically polymerizable composition of the agent is impregnated with the polymer molded body; and the polymerization process is a process of polymerizing the ethylenically unsaturated compound in an expanded state of the polymer molded body impregnated with the radically polymerizable composition. A chain transfer agent and/or a radical polymerization inhibitor are added to the radical polymerizable composition and/or the polymer molded body before the process of impregnating the polymerizable molded body with the radical polymerizable composition.

(2) A method for producing a polishing pad comprising a process of producing a polishing pad by mutually invading a polymer mesh structure obtained by a method of invading a polymer mesh structure as in (1).

(3) A polishing pad comprising a polymer in which a polymer molded body and an ethylenically unsaturated compound are mutually invaded into a polymer mesh structure, and is a polishing pad having a thickness of 1 mm or more and a diameter of 300 mm or more. When the average weight ratio of the polymer molded article is X (%) in the total weight of the polymer molded article and the ethylenically unsaturated compound polymer, the weight ratio of the polymer molded article at any position of the polishing pad is X. Within the range of ±3 (%).

According to the method for producing a mutually invading polymer mesh structure of the present invention, it is possible to obtain a mutually invading polymer mesh structure having excellent uniformity characteristics and high production efficiency.

Moreover, according to the method for producing a polishing pad of the present invention, it is possible to obtain a polishing pad which has high in-plane uniformity of polishing rate during polishing, can eliminate stepping in a short time, and has excellent flattening characteristics, and can reduce between polishing pads. The difference in the polishing characteristics improves the durability of the polishing and the manufacturing efficiency is high.

In the present invention, the mutual intrusion into the polymer network structure system means a polymer mixture system composed of a plurality of polymers, and the polymer mesh composed of the plurality of polymers has a structure in which the polymers invade each other. Further, the structure in which the heterogeneous polymers form a continuous phase with each other may be stabilized by forming a crosslinking point.

In the present invention, the mutually invading polymer network structure can be obtained by immersing a part of a polymer molded body composed of a polymer with an ethylenically unsaturated compound forming another polymer, and polymerizing the ethylenically unsaturated compound. And get it. The polishing pad of the present invention is composed of mutually invading a polymer mesh structure.

In the present invention, a chain transfer agent refers to a compound which reacts with a growth radical to stop an increase in the length of a polymer chain during radical polymerization, and which produces a low molecular radical having reinitiation ability.

Examples of the chain transfer agent include n-butyl mercaptan, isobutyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, second butyl mercaptan, and second-dodecyl sulfur. Alkenyl mercaptan such as alcohol, tri-butyl mercaptan, phenyl mercaptan, toluene thiol, 4-tert-butyl-o-tolylthiophenol, 2-ethylhexyl acetate, hydrazine Ethyl acetate, such as ethyl acetate, ethanedithiol, carbonic acid such as 3 to 18, α-methylstyrene dimer, aromatic hydrocarbon chain transfer agent such as toluene or ethylbenzene, carbon tetrachloride Wait. Here, the alkyl mercaptan may be any of the first stage, the second stage, and the third stage, and may have a substituted alkyl group. These may be used alone or in combination of two or more types. Among them, an aromatic hydrocarbon chain transfer agent and a thiol having an alkyl group having 4 to 12 carbon atoms are preferred. Specific examples thereof include an α-methylstyrene dimer or an aromatic hydrocarbon chain transfer agent such as toluene, a third-butyl mercaptan, n-butyl mercaptan, n-octyl mercaptan, and a positive twelve. An alkylthiol having 4 to 12 carbon atoms such as a thiol.

In the present invention, the chain transfer agent is preferably used in an amount of 0.01 to 20% by weight, more preferably 0.01 to 5% by weight, even more preferably 0.05 to 3% by weight based on 100% by weight of the ethylenically unsaturated compound. When the amount used is less than 0.01% by weight, the effect of the chain transfer agent becomes low. Moreover, when it is more than 5% by weight, mechanical properties such as strength and modulus of elasticity of the obtained polymer are lowered.

In the present invention, the radical polymerization inhibitor is a compound having high reactivity with a radical in a radical polymerization system, and reacts with a radical to produce a passive product. The radical polymerization inhibitor is preferably a compound having an aromatic ring and at least one or more hydroxyl groups.

Examples of the radical polymerization initiator include hydroquinone, hydroquinone monomethyl ether, topanol A, catechol, tert-butylcatechol, 2,6-di- Tributyl-4-methylphenol, thiophene , α-tocopherol, pentaerythritol-indole [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylene double (3 , 5-di-t-butyl-4-hydroxy-hydrocinnamylamine, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonic acid bis ( 1,2,2,6,6-pentamethyl-4-piperidinyl), etc. One or two or more compounds can be selected from these compounds.

In the present invention, the amount of the radical polymerization initiator used is preferably 0.001 to 0.5% by weight, more preferably 0.001 to 0.3% by weight, based on 100% by weight of the ethylenically unsaturated compound, and in the present invention, ethylenic unsaturation The compound means a compound having a radical polymerizable carbon-carbon double bond. Specific examples thereof include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and methyl group. Tert-butyl acrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl methacrylate, tridecyl methacrylate, n-stearyl methacrylate, 2-methacrylic acid 2- Hydroxyethyl ester, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, dimethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethyl methacrylate Aminoethyl ester, methacrylic acid, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, A Methacrylates such as isodecyl acrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, methyl acrylate, isoamyl acrylate, lauryl acrylate, stearyl acrylate, phenoxy acrylate Ethyl ethyl ester, tetrahydrofurfuryl acrylate, Isodecyl enoate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylate, acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, hydroxystyrene, α-methylbenzene Monofunctional ethylenically unsaturated compound such as ethylene dimer, ethylene glycol monomethacrylate, trimethylolpropane trimethacrylate, neopentyl glycol diacrylate, 3-methyl-1,5 - Neopentyl glycol diacrylate, 1,6-butanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, 1,9-decane diacrylate, two A polyfunctional ethylenically unsaturated compound such as hydroxymethyl tricyclodecane diacrylate, trimethylolpropane triacrylate or pentaerythritol tetraacrylate. These ethylenically unsaturated compounds can be used alone or in combination of two or more.

Among these ethylenically unsaturated compounds, a compound selected from the group consisting of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate and butyl methacrylate is easy to form independent bubbles and monomers. It is preferable that the impregnation property is good, the polymerization hardening is easy, and the obtained mutual intrusion into the polymer network structure has high hardness and good flattening properties.

The radical polymerization initiator of the present invention means a compound which can generate a radical by decomposition by heating, light irradiation, radiation or the like. Examples of such a radical polymerization initiator include an azo compound, a peroxide, and the like. Specifically, there are 2,2'-azobisisobutenenitrile, 2,2'-azobis(2-methylbutenenitrile), and 2,2'-azobis (2,4- Dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis An azo polymerization initiator such as (4-methoxy-2,4-dimethylvaleronitrile), cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, and di-peroxide Tributane, tert-butylperoxy-2-ethylbutyrate, tert-butylperoxyisobutyrate, tert-butylperoxytrimethylacetate, tert-butylperoxybenzene Methyl ester, tert-butyl peroxyacetate, diisopropyl peroxydicarbonate, di-second butyl peroxydicarbonate, benzammonium peroxide, ethoxylated ruthenium, peroxidized laurel A peroxide-based polymerization initiator such as hydrazine. The radical polymerization inhibitor is preferably added in an amount of 0.01 to 5% by weight, more preferably 0.05 to 3% by weight, based on 100% by weight of the ethylenically unsaturated compound.

In the present invention, the organic solvent is a compound which does not substantially react when the ethylenically unsaturated compound is polymerized, and is an organic compound which is liquid at normal temperature. Specifically, hexane, dimethylformamide, dimethyl hydrazine, ethanol, methanol or the like can be used. The fact that the organic solvent is not substantially contained means that the radical polymerizable composition has an organic solvent content of less than 1% by weight based on 100% by weight of the ethylenically unsaturated compound. Carbon tetrachloride, toluene, ethylbenzene and the like are generally known as organic solvents, but since such compounds are known to have an effect as a chain transfer agent, they are not equivalent to organic solvents.

In the present invention, the radically polymerizable composition means a composition comprising the above ethylenically unsaturated compound and the above-mentioned radical polymerization initiator. Further, an antioxidant, an anti-aging agent, a filler, a coloring agent, an antifungal agent, an antibacterial agent, a flame retardant, an ultraviolet absorber, or the like may be added to the radically polymerizable composition. The amount of the above compound to be added is preferably in the range of not more than 3% by weight based on 100% by weight of the ethylenically unsaturated compound.

The radical polymerizable composition is preferably a composition substantially free of an organic solvent from the viewpoint of the economical process of eliminating the need to remove the organic solvent.

In the present invention, the polymer molding system refers to a polymer material which is solid at normal temperature. The shaped body may be solid inside, hollow, or foamed. The characteristics are not particularly limited, and it is necessary to immerse the composition in a molded body by immersing in a radically polymerizable composition. Therefore, it must be composed of a material having affinity with the radical polymerizable composition, and the polymer molded body must have flexibility to be expanded. Although depending on the density or impregnation amount of the radical polymerizable composition, the volume of the polymer molded body after immersion is expanded to about 1.03 to 5 times the original volume, and most of it is expanded to about 1.03 to 3 times.

Such a polymer molded body is preferably one composed of a polymer having a polyethylene glycol chain, a polypropylene glycol chain or a polybutadiene glycol chain. Specifically, polyester or polyurethane is mentioned.

The form of the polymer molded body is preferably a foam containing independent cells having an average cell diameter of 10 to 230 μm, and a foam having independent cells having an average cell diameter of 10 to 120 μm is more preferable to contain an average cell diameter. Separate bubbles of 20 to 60 microns are particularly good. By using a scanning electron microscope (SEM) at a magnification of 200 times the surface or the cut surface of the polymer molded body, the image was analyzed by an image processing apparatus, and the bubble diameter of all the images was measured, and the average value of the average number of bubbles was used as an average bubble. diameter.

Further, the apparent density of the polymer molded body is preferably 0.1 to 1.2 g/cm 3 and more preferably 0.5 to 1.0 g/cm 3 . The apparent density can be measured in accordance with the method of Japanese Industrial Standard JIS K 7112. In addition, the radical polymerizable composition contained in the polymer molded body is polymerized in the bubbles in the polymer molded body, and in the expanded state of the polymer molded body, after the polymerization of the ethylenically unsaturated compound, the polymer The bubbles of the molded body are preferably left as they are. As a result, the apparent density of the obtained polishing pad is preferably 0.2 to 1.1 g/cm 3 and more preferably 0.6 to 1.1 g/cm 3 .

The polymer molded article of the present invention is particularly preferably a polyurethane molded article obtained by further comprising a polyurethane, a two-liquid mixed polyol and a polyisocyanate. Here, the polyol means a compound having two or more hydroxyl groups. For example, one or a mixture of two or more selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, ethylene glycol, propylene glycol, and glycerin may be mentioned.

Further, examples of the polyisophthalate include aromatic isocyanate such as toluene polyisoester (TDI), diphenylmethane dipolyisoester (MDI), polymeric MDI, and naphthalene diisocyanate, and butyl diisocyanate. An aliphatic diisocyanate such as a hexyl diisocyanate, an isophorone diisocyanate, a hydrogenated TDI, an alicyclic diisocyanate such as hydrogenated MDI, or the like. These may be selected from one or a mixture of two or more of these isocyanates.

In the preparation of the polymer molded body, a crosslinking agent, a chain extender, a bubble stabilizer, a foaming agent, a resinized catalyst, a bubble-forming catalyst, an antioxidant, and an anti-aging agent may be contained in addition to the polyol and the polyisocyanate. , fillers, plasticizers, colorants, mold inhibitors, antibacterial agents, flame retardants, UV absorbers.

The method of preparing the polymer molded body is not particularly limited, and methods such as injection molding and reaction molding can be used. In particular, when a polyurethane molded article is prepared, a high-pressure injection machine which instantaneously mixes the raw materials in a mixing head or a low pressure of each raw material which is mechanically mixed and supplied to the mixing head by using a stirring blade or the like is used. It is preferable that the injection machine or the like is formed by molding or thick molding.

Next, a method of manufacturing the mutually invading polymer mesh structure will be described. The mutually invading polymer mesh structure can be produced by an immersion process and a polymerization process, wherein the immersion process is performed by impregnating a polymer molded body with a radical polymerizable composition containing the ethylenically unsaturated compound and a radical polymerization initiator; The process is a process in which the ethylenically unsaturated compound is polymerized in an expanded state of the polymer molded body impregnated with the radical polymerizable composition. Here, the method for producing the mutually invading polymer mesh structure of the present invention is the radical polymerizable composition and/or the polymer molded body before the process of impregnating the polymer molded body with the radical polymerizable composition. The chain transfer agent and/or the radical polymerization inhibitor are added.

That is, the process of impregnating a radical polymerizable composition into a polymer molded body and the process of polymerizing an ethylenically unsaturated compound of the present invention are characterized in that a chain transfer agent and/or a radical polymerization inhibition are present in the system. Agent. According to this method, the obtained mutually invading polymer mesh structure has excellent uniformity of mechanical properties such as tensile strength and tensile elongation. Further, when the mutually invading polymer mesh structure is used as a polishing pad, the in-plane uniformity of the polishing rate at the time of polishing is high, the planarization property is excellent, the durability of the polishing pad can be improved, and the difference in characteristics between the polishing pads is small. Therefore, the CMP polishing process is stable.

Although the reason is not necessarily clear, it is presumed that when a chain transfer agent is added for production, since there is no intense heat generation during the polymerization reaction, the temperature in the reaction system is substantially constant over time, the polymerization reaction proceeds stably, and the generated mutual intrusion occurs. Since the chemical composition or characteristics of the polymer mesh structure are uniform, the polishing pad produced by invading the polymer mesh structure exhibits stable characteristics in the surface of the polishing pad and between the plurality of polishing pads. The chain transfer agent is particularly effective in homogenizing the chemical composition and characteristics in the thickness direction when invading the polymer mesh structure. Therefore, it is particularly effective to homogenize the chemical composition and characteristics between the plurality of polishing pads when the polyethylene mesh structure is infiltrated into each other to form a polishing pad.

Further, when a radical polymerization initiator is added for production, the entire reaction system is unified at the start of the polymerization reaction, and the entire reaction system is substantially the same from the start to the end of the polymerization reaction, and as a result, the characteristic deviation of the reaction cured product is obtained. Small, it is possible to obtain a high-uniformity mutual intrusion into a polymer mesh structure or a polishing pad. The radical polymerization inhibitor is particularly effective in homogenizing the chemical composition or characteristics in the in-plane direction when invading the polymer mesh structure.

Further, as described above, the radical polymerization initiator is substantially a composition which does not contain an organic solvent, and it is not necessary to have a process for removing the organic solvent, and is preferable from the viewpoint of economy. However, in the conventional production method, when the radical polymerizable composition does not contain an organic solvent, the radical polymerization composition is impregnated with high viscosity due to the start of the polymerization reaction and the viscosity increase during the impregnation of the polymer molded article. The speed at which the molecular molded body is slowed down and the time required for manufacturing becomes long. In the present invention, in the process of immersing the radical polymerizable composition in the polymer molded body, the viscosity of the composition can be prevented from increasing by the presence of the chain transfer agent and/or the radical polymerization inhibitor. Thereby, since a radically polymerizable composition which does not substantially contain an organic solvent can be used, the process of removing an organic solvent is unnecessary, and manufacturing time and process can be shortened, and manufacturing efficiency can be improved.

Although it is also possible to add only one of a chain transfer agent and a radical polymerization inhibitor, there is a synergistic effect when two parties are added.

The chain transfer agent and the radical polymerization inhibitor may be added to the polymer molded body or may be used in a mixture of the radical polymerizable composition. When a chain transfer agent and/or a radical polymerization inhibitor are used for both the radically polymerizable composition and the polymer molded article, the same compound or a different compound may be used.

Further, in order to increase the polymerization inhibitory effect, it is preferred to use a radical polymerization inhibitor to impregnate the radically polymerizable composition and/or polymerize in the presence of oxygen or a gas containing oxygen. In this case, a preferred radical polymerization inhibitor may be exemplified by Hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, topanol A, and the like. As the gas containing oxygen, a gas obtained by diluting air, oxygen, or the like with an inert gas may be used. Examples of the inert gas include nitrogen, helium, hydrogen, and the like. The oxygen concentration at the time of dilution is not particularly limited, and is preferably 1% by volume or more. Since it is inexpensive, it is preferable to use a gas obtained by using dry air or diluting dry air with nitrogen as a gas containing oxygen.

In order to have an effect of suppressing the progress of the radical polymerization reaction, it is preferred that the chain transfer agent and/or the radical polymerization inhibitor are present in a uniform concentration in the reaction system.

One of the methods for uniformly distributing the chain transfer agent and/or the radical polymerization inhibitor in the reaction system may be a method of adding a polymer molded body to a raw material thereof. For example, when preparing a polymer molded body, a chain transfer agent and/or a radical polymerization inhibitor are mixed in a polyol of a raw material of a polyurethane, and by a reaction injection molding method (RIM), The polyol and the polyisocyanate are subjected to reaction injection molding, and a polyurethane polymer molded body in which a chain transfer agent and/or a radical polymerization inhibitor are distributed in a uniform concentration can be obtained. Then, by impregnating the high-molecular-weight molded product with a radical polymerizable composition and polymerizing it, it is possible to infiltrate into the polymer network structure which is chemically uniform in composition composed of the polyurethane and the ethylenically unsaturated compound. body.

In the case of mixing the chain transfer agent in the preparation of the polymer molded article, the content of the chain transfer agent is preferably 0.01 to 20% by weight, more preferably 0.01 to 5% by weight, based on 100% by weight of the polymer molded article. ~3% by weight is more preferred. When the content is less than 0.01% by weight, the effect of the chain transfer agent may not be exhibited. Moreover, when the content is more than 20% by weight, mechanical properties such as strength and modulus of elasticity may be lowered.

The content of the chain transfer agent in the polymer molded body can be obtained by pulverizing the polymer molded body, using a solution extracted by a Soxhlet's extractor using chloroform, by a gas chromatograph. Quantitative analysis to determine.

Another method for uniformly distributing the chain transfer agent and/or the radical polymerization inhibitor in the reaction system is to add a lower molecular weight chain transfer agent and/or free in the radically polymerizable composition. A method of polymerizing an inhibitor. When the chain transfer agent having a large molecular weight and/or the radical polymerization inhibitor impregnate the polymer molded body, the diffusion rate is slow and it is not uniformly distributed in the polymer molded body. On the other hand, the lower molecular weight chain transfer agent and/or the radical polymerization inhibitor have a high diffusion rate when the polymer molded body is impregnated, and can be distributed in a polymer molded body at a uniform concentration. Therefore, the obtained mutually invading polymer network structure is chemically homogeneous. Such a chain transfer agent or a radical polymerization inhibitor is preferably a compound having a molecular weight of 350 or less. Examples of the chain transfer agent having a molecular weight of 350 or less include an α-methylstyrene dimer, an aromatic hydrocarbon having a molecular weight of 350 or less, such as ethylbenzene or toluene, and a third butyl thiol or n-butyl thiol. a mercaptan having an alkyl group having 4 to 12 carbon atoms such as octyl mercaptan or n-dodecyl mercaptan. Further, examples of the radical polymerization inhibitor having a molecular weight of 350 or less include hydroquinone, hydroquinone monomethyl ether, phenol, tert-butyl phenol, tert-butyl pyrophenol, 2,6-di- Third butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, and the like.

When the polymer mesh structure is invaded into each other, the weight ratio of the polymer obtained by polymerizing the polymer molded body and the ethylenically unsaturated compound is preferably 100/5 to 100/300, and 100/50 to 100/200. Better. When the weight ratio is less than 100/5, the change in characteristics when there is only a polymer molded body is small. When the weight ratio is more than 100/300, the time required for impregnating the polymerizable body with the radical polymerizable composition increases, which may be undesirable.

The process of impregnating the polymerizable body with the radical polymerizable composition is preferably carried out at a temperature of from 15 to 60 ° C for from 3 hours to 20 days, more preferably from 3 hours to 10 days.

The polishing pad was produced by invading the polymer mesh structure obtained by the above method. The polishing pad can be produced by forming a predetermined shape and a predetermined thickness by invading the polymer mesh structure, and then forming a groove or the like on the surface as necessary.

The thickness of the polishing pad is preferably 1 mm or more. Further, the thickness of the polishing pad is preferably 5 mm or less. The diameter of the polishing pad is preferably 300 mm or more. Further, the diameter of the polishing pad is preferably 2 meters or less. When the thickness of the polishing pad is less than 1 mm or the diameter is less than 300 mm, there is a possibility that the durability of the polishing pad is shortened. When the thickness of the polishing pad is more than 5 mm or the diameter is more than 2 meters, there is a possibility that the polishing pad is difficult to be replaced and the film cannot be uniformly attached to the polishing table.

As described above, when the production method of the present invention is used, the variation in chemical composition is small, and a uniform polishing pad can be obtained. One aspect of the polishing pad of the present invention comprises a polymer in which a polymer molded body and an ethylenically unsaturated compound are mutually invaded into a polymer mesh structure, and is a polishing pad having a thickness of 1 mm or more and a diameter of 300 mm or more. When the average weight ratio of the polymer molded article is X (%) based on the total weight of the polymer molded article and the ethylenically unsaturated compound polymer, the weight ratio of the polymer molded article at any position of the polishing pad is A polishing pad in the range of X ± 3 (%). That is, as described in the examples, the composition at each position of the polishing pad was measured, and the weight ratio of the polymer molded body to the total weight of the polymer molded body and the ethylenically unsaturated compound polymer was determined as an average. The value is X (%). Here, the minimum value among the weight ratios of the polymer molded articles measured is X-3 (%) or more, and the maximum value is X + 3 (%) or less. Further, the weight ratio of the ethylenically unsaturated compound polymer at any position of the polishing pad is in the range of (100-X) ± 3%.

The weight ratio of the polymer molded body to the polymer of the ethylenically unsaturated compound is determined by infrared absorption spectrometry. The weight ratio of the polymer molded body to the ethylenically unsaturated compound can be calculated from the ratio of the absorbance inherently absorbed in the polymer molded article to the absorbance inherently absorbed in the ethylenically unsaturated compound polymer. The size of the obtained spectral region differs depending on the measurement method and the pore diameter. For example, in the usual infrared spectroscopy, the diameter of the aperture is about 1 mm, and the weight ratio of the two polymers in the 1 mm order region can be obtained. When the microscopic infrared spectroscopy method is used, the pore diameter is about 100 μm in diameter, and the weight ratio of the two polymers in the region of 100 μm can be obtained. Further, when the Raman spectroscopy method is used, the pore diameter can obtain the weight ratio of the two polymers in the region of 1 μm. In the mutually invading polymer network structure of the present invention, the polymer molded body and the polymer of the ethylenically unsaturated compound are very finely mixed because the weight ratio of the two is uniform in a region of about 1 μm to about 1 mm. The same result can be obtained using either method.

The polishing pad of the present invention preferably has a tensile breaking strength of 13 MPa or more. Further, the polishing pad of the present invention preferably has a tensile elongation at break of 150% or more. The tensile strength at break and the tensile elongation at break are in the environment of 23 ° C and 50% RH. According to JIS K 7113:1995, the small test piece No. 1 (the thickness of the test piece is 1~2 mm) is used as the distance between the chucks. The value obtained by the tensile test was carried out under conditions of 58 mm and a test speed of 50 mm/min. When the tensile breaking strength is less than 13 MPa, the in-plane uniformity of the polishing rate at the time of polishing and the polishing property such as the durability of the polishing pad are lowered. When the tensile elongation at break is less than 150%, the polishing properties such as in-plane uniformity and durability of the polishing rate during polishing are lowered. The tensile strength at break is preferably 50 MPa or less. When the tensile breaking strength is more than 50 MPa, the polishing pad tends to become brittle. Further, the tensile elongation at break is preferably 1000% or less, and when the tensile elongation at break is 1000% or more, the elasticity of the polishing pad is too strong.

The polishing pad of the present invention preferably has an average cell diameter of from 10 to 230 μm. The average bubble diameter is preferably 10 to 120 μm, and 20 to 60 μm. The surface of the polishing pad or the cut surface was observed by a scanning electron microscope (SEM) with a magnification of 200 times, and the image was analyzed by an image processing apparatus to measure the diameter of all the bubbles in the image, and the average value of the number averaged was used as the average bubble diameter. On the surface of the polishing pad, it is preferred that the flat surface and the opening from the bubble are present in an appropriate ratio. The number of bubbles in any of the cut surfaces is preferably 10 to 1000 pieces/mm 2 , and more preferably 200 to 600 pieces/mm 2 .

The polishing pad of the present invention preferably has an apparent density of 0.2 to 1.1 g/cm 3 . The apparent density is a value measured using a Herbert-type pycnometer in the form of purified water as a medium, and can be measured in accordance with the method of Japanese Industrial Standard JIS K 7112. When the apparent density is less than 0.2, the local flatness is poor and the overall step difference is large in terms of polishing properties. When the density is more than 1.1, scratching is likely to occur in terms of polishing characteristics. The apparent density is preferably in the range of 0.4 to 0.9, and more preferably in the range of 0.45 to 0.85.

The polishing pad of the present invention can be used for polishing a semiconductor substrate such as a tantalum wafer, an optical component such as a lens, an electronic material such as a magnetic head or a hard disk, or the like. In particular, when a semiconductor wafer for polishing an object to be polished is polished by a chemical mechanical polishing (CMP) technique for the purpose of planarizing a semiconductor wafer, it is used as a polishing pad. In the CMP process, as a polishing pad, using a polishing slurry composed of an abrasive and a chemical liquid, the semiconductor wafer surface is polished by relatively moving the semiconductor wafer and the polishing pad to achieve a flat surface of the semiconductor wafer. Smooth purpose.

The polishing pad of the present invention can also be used to polish optical components such as optical lenses, optical iridium, filters, and optical waveguides. The material to be polished includes glass, quartz, crystal, sapphire, transparent resin, lithium niobate, lithium niobate, and the like.

Further, other uses can be used for polishing with potassium arsenic, potassium phosphorus, indium phosphorus, pure iron, alumina, tantalum carbide, tantalum nitride, ceramics, alloys, resins, and the like.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited thereto. Further, the evaluation was carried out as follows.

[Average bubble diameter] The surface of the sample or the cut surface was observed at a magnification of 200 times using a scanning electron microscope "SEM2400" (Hitachi, Ltd.), and the image was analyzed by an image processing device to measure the bubble diameter of the image. The value is taken as the average bubble diameter.

[Apparent density] Measured using a pycnometer (Herbert type) in accordance with the method of JIS K 7112.

[Tensile test] Using a tensile tester RTM-100 (manufactured by ORIENTEC), the breaking strength and the elongation at break were measured using the following measurement conditions. The average value of the five test pieces was used as the measured value.

Laboratory temperature: 23 ° C Laboratory humidity: 50% test piece shape: JIS K 7113: 1995 type 1 small test piece thickness: 1 ~ 2 mm distance between chucks: 58 mm test speed: 50 mm /minute

[Measurement of the weight ratio of polyurethane to polymethyl methacrylate] The measured sheet was cut into a size of 600 mm × 600 mm, and further subdivided into 400 pieces of 30 mm × 30 mm pieces. In the central portion of the small piece of each small piece, the infrared absorption spectrum was measured as follows, and the polyurethane and polymethyl methacrylate were calculated from the absorbance ratio of the infrared absorption from the polyurethane and polymethyl methacrylate. Weight ratio. The weight ratio of the polyurethane to the total weight of the polyurethane and the polymethyl methacrylate was determined for 400 small pieces, and the average value X, the minimum value, and the maximum value were determined.

Apparatus: Fourier transform infrared absorption spectrometer "AVATAR360" (manufactured by Nicolet) Accessories: horizontally placed once reflection ATR measuring device "OMNI-samoler" ATR crystal: Ge, incident angle 45 degrees Measurement conditions: 32 times of scanning, decomposition ability 4cm ^{- 1} measured at the: surface of the central portion 3 cm × 3 cm × thickness of 2 mm of the test piece, is measured both negative analytical methods: 1105cm ^{- 1-carboxylate} as an absorbent from the polyamine. Use 1150cm ^{- 1} as an absorption of from polymethyl methacrylate. The weight ratio of polyurethane to polymethyl methacrylate (hereinafter referred to as PMMA) PU: PMMA is calculated from absorbance of 2 absorption ratio ABS (PU): ABS (PMMA). In the calculation, the analysis software "OMNICE.SP5.1" attached to the device is used. The processing of the spectral data carries out the following steps. (1) Automatic baseline correction, (2) automatic smoothing, (3) Y-axis normalization, (4) sharp detection

[Polishing Evaluation] Using a "Suba 400" (manufactured by Rodel-Nitta Co., Ltd.) as a buffer layer, a polishing pad of a predetermined evaluation was bonded using a double-sided adhesive tape to prepare a laminated polishing pad. The laminated polishing pad was attached to the platform of the polishing apparatus, and the diamond adjuster was pressed on the laminated polishing pad at a pressure of 0.05 MPa, and the polishing table was rotated in the same direction at a rotation number of 32 rpm and a rotation number of 30 rpm. The polishing pad was adjusted while supplying purified water to the polishing pad at a ratio of 100 ml/min.

Next, a 6-inch wafer was mounted on the polishing pad of the polishing apparatus and rotated at 40 rpm. The laminated polishing pad was attached to the polishing table of the polishing apparatus and rotated at 40 rpm in the same direction as the rotation direction of the polishing pad. The enamel slurry was supplied at 180 ml/min, and the polishing was performed at a polishing pressure of 0.06 MPa for 1 minute to measure the polishing rate of the oxide film on the surface of the ruthenium wafer. After the polishing, the surface of the wafer was washed with a polyvinyl alcohol sponge while directly supplying the purified water without drying the surface of the wafer, and the compressed air was blown and dried.

20 sheets of evaluation wafers were polished, and the oxide film polishing rate of the 20th sheet was measured. Next, the polishing was continued, and the polishing rate of the oxide film of the 500th sheet was measured.

[Polishing speed] The wafer thickness before and after polishing was measured by using "RAMUDAES" VM-8000J (manufactured by DAINIPPON SCREEN MFG Co., Ltd.) using an optical interference type membrane pressure measuring device, and the polishing amount (polishing speed) per unit time was calculated. A test wafer for evaluation of a thermal oxide film of about 1.2 μm formed on a 6-inch wafer was used.

[In-Plane Uniformity] The polishing rate of 49 points in the diameter direction of the wafer was measured, and the difference between the maximum value and the minimum value was divided by the value of twice the average value of 49 points, and the value was calculated by multiplied by 100 times as the in-plane uniformity. (%) in-plane uniformity (%) = (maximum - minimum value) × 100 / 2 × average

[Flatness Characteristics] After 40 wafers for the polishing treatment evaluation, a patterned oxide film wafer having a pattern having a pattern height of 0.60 μm and a line and a gap of 300 μm and a gap of 30 μm was used, and was polished as described above. The polishing time was measured at 30, 60, 90, 120, 150, and 180 seconds, and the time when the step was flattened to 0.10 μm or less was obtained.

(Comparative Example 1)

The following raw material composition was added to each of the first raw material tank and the second raw material tank of the RIM molding machine, and after the nitrogen gas was placed in the first raw material tank, it was poured into a mold and hardened to obtain a mixture of 850 mm × 850 mm and a thickness of 12 mm. A urethane shaped body. The apparent density of the obtained polyurethane shaped article was 0.82 g/cm 3 , and independent bubbles having an average cell diameter of 28 μm were observed.

<First raw material tank> polypropylene glycol 85 parts by weight of diethylene glycol 15 parts by weight of tin octylate 0.5 parts by weight of anthraquinone bubble stabilizer 3 parts by weight of purified water 0.3 parts by weight

<Second raw material tank> diphenylmethane diisocyanate 120 parts by weight

Next, the following radical polymerizable composition was prepared, and after immersing the above-mentioned polyurethane shaped body at 20 ° C for 7 days, the radically polymerizable composition was immersed in the entire polyurethane shaped body. The weight ratio of the polyurethane shaped article to the radically polymerizable composition was 100/150.

Methyl methacrylate 300 parts by weight of azobisisobutyronitrile 0.9 parts by weight

The urethane molded body expanded by the immersion was sandwiched between two glass plates, and the periphery was sealed, and then heated at 70 ° C for 5 hours, followed by heating in an oven at 100 ° C. The mixture was hardened in 3 hours to obtain a mutual intrusion into the polymer network structure. The obtained intrusive polymer mesh structure was released from the glass, and the weight was measured. Further, the mixture was dried at 50 ° C for 12 hours, then dried at 100 ° C for 12 hours, and further dried at room temperature for 12 hours. Immediately after the weight was measured, the weight was not reduced as compared with that before drying.

The center portion in the thickness direction of the mutually invading polymer mesh structure was subjected to slicing and surface grinding to obtain a sheet having a thickness of 2 mm. When the No. 1 shaped test piece was punched from the center of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 11.6 MPa and 270%, respectively. Further, when the No. 1 shaped test piece was punched from the end of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were each 9.8 MPa and 240%.

A sheet having a thickness of 2 mm was taken out from the center portion in the thickness direction described above, and the weight ratio of the polyurethane to the PMMA was calculated. As a result, the weight ratio of the polyurethane in the 400 small pieces was 43.3%, the minimum value was 37.3%, and the maximum value was 49.2%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/130.9.

A sheet having a thickness of 2 mm was taken out from the center portion in the thickness direction, and a circle having a diameter of 600 mm was punched out, and a groove having a width of 1.5 mm, a depth of 0.5 mm, and a pitch of 30 mm was formed on one surface to form a polishing pad. The polishing pad had an apparent density of 0.85 g/cm 3 and the closed cells had an average cell diameter of 34 μm. It was observed that there were 395/mm 2 openings from the bubbles on the surface.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1800 Å/min and 1850 Å/min, and the in-plane uniformity was 15% and 16%, respectively. The polishing rate after grinding 500 sheets was 800 angstroms/minute, and the in-plane uniformity was 30%. Further, the flattening property is flattened and it takes 15 seconds to polish.

(Comparative Example 2)

The portions of the comparative example 1 which invaded the polymer mesh structure in the thickness direction of 1/5 and 4/5 were sliced and surface-ground to obtain a sheet having a thickness of 2 mm. The No. 1 shaped test piece was punched from the center of the film, and the tensile breaking strength and tensile elongation at break were measured, and each was tensile fracture strength of 9.3 MPa and tensile elongation at break of 180%, and tensile fracture. The strength is 8.9 MPa and the tensile elongation at break is 190%.

In Comparative Example 1 and Comparative Example 2, tensile tensile strength and tensile elongation at break of a tensile test piece having a thickness of about 2 mm obtained from intrusion into a polymer mesh structure, and a central portion and a periphery in the sheet. There is a significant difference between the portion and the central sheet in the thickness direction and the sheet of the top sheet.

Next, the weight ratio of the polyurethane of the sum of the polyurethane and the PMMA was calculated from the sheet having a thickness of 2 mm obtained from the 1/5 portion in the thickness direction. As a result, the weight ratio of the polyurethane in 400 small pieces was 36.4%, the minimum value was 30.6%, and the maximum value was 42.4%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/174.7.

From the results of Comparative Example 1 and Comparative Example 2, it was found that the composition distribution width in the thin surface of either one was large, and the composition difference between the central sheet in the thickness direction and the sheet of the surface layer sheet was large.

(Example 1)

In the same manner as in Comparative Example 1, except that the first composition was used in the first raw material tank, and the polyurethane containing 10.2% by weight of ethylbenzene as a chain transfer agent was used with respect to 100% by weight of the polyurethane, Invade the polymer mesh structure and the polishing pad.

<First raw material tank> polypropylene glycol 85 parts by weight of ethylene glycol 1.5 parts by weight of ethylbenzene 25 parts by weight of tin octylate 0.5 parts by weight of anthraquinone bubble stabilizer 3 parts by weight of purified water 0.3 parts by weight

The resulting polishing pad had an apparent density of 0.87 g/cm 3 and the average bubble of the closed cells was 35 μm. It was observed that the surface had 400/mm 3 openings from the bubbles. The tensile breaking strength and tensile elongation at break of the obtained sheet having a thickness of 2 mm from the thickness direction of the mutually invading polymer mesh structure were each a tensile breaking strength of 13.2 MPa and a tensile elongation at break of 270%.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1820 Å/min and 1820 Å/min, and the in-plane uniformity was 8% and 7%, respectively. The polishing rate after grinding 500 sheets was 1810 Å/min, and the in-plane uniformity was 8%. Moreover, the flattening property is flattened and it takes about 120 seconds of polishing.

(Example 2)

The following composition was used in the second raw material tank, and a polyurethane containing 2.9% by weight of α-methylstyrene dimer as a chain transfer agent was used in comparison with 100% by weight of polyurethane, and a comparative example. 1 In the same manner, a mutually invading polymer mesh structure and a polishing pad were produced.

<Second raw material tank> diphenylmethane diisocyanate 120 parts by weight of α-methylstyrene dimer 6.5 parts by weight

The apparent density of the mutually invading polymer mesh structure was 0.86 g/cm 3 and the average bubble diameter of the closed cells was 35 μm. It was observed that there were 367/mm 2 openings from the bubbles on the surface. The tensile breaking strength and the tensile elongation at break of the sheet having a thickness of 2 mm obtained from the thickness direction of the mutually invading polymer mesh structure were each a tensile breaking strength of 15.8 MPa and a tensile elongation at break of 315%.

Next, the weight ratio of the polyurethane to the PMMA was calculated from the above-mentioned sheet. As a result, the weight ratio of the polyurethane in the 400 small pieces was 40.3%, the minimum value was 38.1%, and the maximum value was 42.3%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/148.1.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1860 Å/min and 1890 Å/min, and the in-plane uniformity was 7% and 8%, respectively. The polishing rate after grinding 500 sheets was 1,850 angstroms/minute, and the in-plane uniformity was 7%. Moreover, the flattening property is flattened and it takes about 120 seconds of polishing.

(Example 3)

The portions in the thickness direction of the polymer mesh structure of Example 2 which were in the thickness direction of 1/5 and 4/5 were sliced and surface-ground to obtain a sheet having a thickness of 2 mm. When the No. 1 shaped test piece was punched from the center of the film and the tensile breaking strength and tensile elongation at break were measured, each was tensile fracture strength of 15.7 MPa and tensile elongation at break of 314%, and tensile fracture. The strength was 15.6 MPa and the tensile elongation at break was 310%.

Next, the weight ratio of the polyurethane to the PMMA was calculated from the above-mentioned sheet. As a result, the weight ratio of the polyurethane in the 400 small pieces was 39.6%, the minimum value was 37.6%, and the maximum value was 41.7%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/152.5.

In Example 2 and Example 3, tensile tensile strength and tensile elongation at break of a tensile test piece having a thickness of about 2 mm obtained from the same mutual intrusion into the polymer mesh structure, in the sheet and in the sheet The difference between the two is small. Further, it was found that the difference in the average value of the weight ratio of the sheet in the center in the thickness direction to the sheet in the surface layer was small, and by adding the chain transfer agent, the effect of reducing the composition distribution particularly in the thickness direction can be observed. .

(Example 4)

The first raw material tank was used in the same manner as in Comparative Example 1, except that the following composition was used, and 0.09 wt% of α-methylstyrene dimer was used as a chain transfer agent with respect to 100% by weight of the polyurethane. A polyurethane shaped article having closed cells having an apparent density of 0.31 g/cm 3 and an average cell diameter of 80 μm.

<First raw material tank> polypropylene glycol 85 parts by weight of ethylene glycol diethylene glycol 15 parts by weight of α-methylstyrene dimer 0.2 parts by weight of tin octylate 0.5 parts by weight of anthraquinone bubble stabilizer 3 parts by weight of purified water 0.3 parts by weight

Then, the following radical polymerizable composition was prepared, and after immersing the above-mentioned polyurethane shaped body at 20 ° C for 24 hours, the radically polymerizable composition was immersed in the entire polyurethane molded article. The weight ratio of the polyurethane shaped article to the radically polymerizable composition was 100/30.

Methyl methacrylate 300 parts by weight of azobis(2-methylbutyronitrile) 1.5 parts by weight

The urethane molded body expanded by the immersion was sandwiched between two glass plates, and the periphery was sealed, and then heated at 70 ° C for 5 hours, followed by heating in an oven at 100 ° C. The mixture was hardened in 3 hours to obtain a mutual intrusion into the polymer network structure.

The center portion in the thickness direction of the mutually invading polymer mesh structure was subjected to slicing and surface grinding to obtain a sheet having a thickness of 2 mm.

Next, a groove having a width of 1.0 mm, a depth of 0.5 mm, and a pitch of 18 mm was formed on the one surface by punching a circle having a diameter of 600 mm from the sheet to form a polishing pad. The polishing pad had an apparent density of 0.32 g/cm 3 and the closed cells had an average cell diameter of 85 μm. It was observed that there were 76/mm 2 openings from the bubbles on the surface.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1220 Å/min and 1240 Å/min, and the in-plane uniformity was 9% and 10%, respectively. The polishing rate after grinding 500 sheets was 1,220 Å/min, and the in-plane uniformity was 9%.

(Example 5)

The same procedure as in Comparative Example 1 was carried out except that the following composition was used as the radical polymerizable composition, and the intrusion into the polymer mesh structure and the polishing pad was produced.

Methyl methacrylate 300 parts by weight of azobisisobutyronitrile 0.9 parts by weight of n-octyl mercaptan 0.9 parts by weight

The apparent density of the polishing pad was 0.88 g/cm 3 and the average bubble diameter of the closed cells was 34 μm. It was observed that there were 390/mm 2 openings from the bubbles on the surface. The tensile breaking strength and the tensile elongation at break of the obtained sheet having a thickness of 2 mm from the thickness direction of the mutually invading polymer mesh structure were each a tensile breaking strength of 16.0 MPa and a tensile elongation at break of 310%.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1900 Å/min and 1900 Å/min, and the in-plane uniformity was 7% and 8%, respectively. The polishing rate after grinding 500 sheets was 1,850 angstroms/minute, and the in-plane uniformity was 8%. Moreover, the flattening property is flattened and it takes about 120 seconds of polishing.

(Example 6)

The same procedure as in Comparative Example 1 was carried out except that the following composition was used as the radical polymerizable composition, and the intrusion into the polymer mesh structure and the polishing pad was produced.

Methyl methacrylate 300 parts by weight of azobisisobutyronitrile 0.9 parts by weight of α-methylstyrene dimer 1.2 parts by weight of hydroquinone monomethyl ether 0.06 parts by weight

The apparent density of the polishing pad was 0.86 g/cm 3 and the average bubble diameter of the closed cells was 34 μm. It was observed that there were 391/mm 2 openings from the cells on the surface.

The solid state NMR (nuclear magnetic resonance) method was used to measure the relaxation time of the intrusion into the polymer network structure, and it was confirmed that the PMMA has a structure in which PMMA is dispersed at a level of several tens of nanometers or less, and the polyurethane is urethane. The two polymer chains of the ester and PMMA invade each other, and the polymer chains are entangled with each other. In other words, the relaxation time from the mutual invasion into the polymer mesh structure is longer than the relaxation time of the polyurethane molded article alone and the methyl methacrylate polymer alone, and it is confirmed that the mutually invading polymer mesh structure is formed. .

The center portion in the thickness direction of the mutually invading polymer mesh structure was subjected to slicing and surface grinding to obtain a sheet having a thickness of 2 mm. When the No. 1 shaped test piece was punched from the center of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 15.5 MPa and 320%, respectively.

Next, the weight ratio of the polyurethane to the PMMA was calculated from the above-mentioned sheet. As a result, the weight ratio of the polyurethane in 400 small pieces was 40.1%, the minimum value was 38.6%, and the maximum value was 41.4%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/149.4.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1850 Å/min and 1900 Å/min, and the in-plane uniformity was 7% and 7%, respectively. The polishing rate after grinding 500 sheets was 1,850 angstroms/minute, and the in-plane uniformity was 7%. Moreover, the flattening property is flattened and it takes about 120 seconds of polishing.

(Example 7)

The portions in the thickness direction of the polymer mesh structure of Example 6 which were in the thickness direction of 1/5 and 4/5 were sliced and surface-ground to obtain a sheet having a thickness of 2 mm. When the No. 1 shaped test piece was punched from the center of the film and the tensile breaking strength and tensile elongation at break were measured, each was tensile fracture strength of 15.6 MPa and tensile elongation at break of 312%, and tensile fracture. The strength is 15.5 MPa and the tensile elongation at break is 316%.

Next, the weight ratio of the polyurethane of the sum of the polyurethane and the PMMA was calculated from the sheet having a thickness of 2 mm obtained from the 1/5 portion in the thickness direction. As a result, the weight ratio of the polyurethane in the 400 small pieces was 39.9%, the minimum value was 38.7%, and the maximum value was 41.4%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/150.6.

From the results of Example 6 and Example 7, the values of the tensile rupture strength and the tensile elongation at break of the tensile test piece having a thickness of about 2 mm obtained from the same mutual intrusion into the polymer mesh structure were obtained in the sheet and The difference between the sheets is small. Further, the distribution in the sheet of the weight ratio of the polyurethane of Example 6 and Example 7 was 40.1 ± 1.4 (%) and 39.9 ± 1.4 (%), respectively, and the composition distribution width in the sheet surface was small. Further, the composition of the sheet from the center in the thickness direction was substantially the same as the sheet composition of the surface layer, and it was found that the composition in the thickness direction was also uniform. That is, it was found that by using a chain transfer agent and a polymerization inhibitor in combination, the uniformity of composition in the thin side and the uniformity of the composition between the sheets can be simultaneously improved.

(Example 8)

Using the polyurethane raw material composition of Comparative Example 1, a polyurethane molded article having an apparent density of 0.51 g/cm 3 and an average bubble of 77 μm was obtained.

Then, the following radical polymerizable composition was prepared, and after immersing the above-mentioned polyurethane shaped body at 20 ° C for 24 hours, the radically polymerizable composition was immersed in the entire polyurethane molded article. The weight ratio of the polyurethane shaped article to the radically polymerizable composition was 100/50.

Methyl methacrylate 300 parts by weight of azo (2-methylbutyronitrile) 1.5 parts by weight of n-dodecyl mercaptan 0.7 parts by weight

The urethane molded body expanded by the immersion was sandwiched between two glass plates, and the periphery was sealed, and then heated at 70 ° C for 5 hours, followed by heating in an oven at 100 ° C. The mixture was hardened in 3 hours to obtain a mutual intrusion into the polymer network structure.

The center portion in the thickness direction of the mutually invading polymer mesh structure was subjected to slicing and surface grinding to obtain a sheet having a thickness of 2 mm.

To the above-mentioned sheet, a circle having a diameter of 600 mm was punched, and a groove having a width of 1.0 mm, a depth of 0.5 mm, and a pitch of 18 mm was formed on one side to form a polishing pad. The polishing pad had an apparent density of 0.55 g/cm 3 and the closed cells had an average cell diameter of 83 μm. It was observed that there were 75/mm 2 openings from the bubbles on the surface.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1200 Å/min and 1230 Å/min, and the in-plane uniformity was 10% and 9%, respectively. The polishing rate after grinding 500 sheets was 1210 Å/min, and the in-plane uniformity was 9%.

(Comparative Example 4)

The following raw material composition was added to each of the first raw material tank and the second raw material tank of the RIM molding machine, and after the nitrogen gas was placed in the first raw material tank, it was poured into a mold and hardened to obtain a mixture of 850 mm × 850 mm and a thickness of 12 mm. A urethane shaped body. The apparent density of the obtained polyurethane shaped article was 0.77 g/cm 3 , and closed cells having an average cell diameter of 32 μm were observed.

<First raw material tank> polypropylene glycol 85 parts by weight of diethylene glycol 15 parts by weight of tin octylate 0.5 parts by weight of anthraquinone bubble stabilizer 3 parts by weight of purified water 0.3 parts by weight

<Second raw material tank> diphenylmethane diisocyanate 120 parts by weight

Then, the following radical polymerizable composition was prepared, and after immersing the above-mentioned polyurethane plastisate at 20 ° C for 3 days, the radical polymerizable composition was not fully infiltrated into the polyurethane molded article. So keep immersing. Further, when the total amount of the radically polymerizable composition was immersed for 7 days at 20 ° C for 4 days, the radical polymerizable composition was immersed in the polyurethane molded article. The weight ratio of the polyurethane shaped article to the radically polymerizable composition is 100/160, but since the organic component is removed after curing, the weight ratio of the polyurethane shaped body to the radically polymerizable composition is It becomes essentially 100/120.

Methyl methacrylate 300 parts by weight of azobisisobutyronitrile 1.5 parts by weight of n-decane 100 parts by weight

The urethane molded body expanded by the immersion was sandwiched between two glass plates, and the periphery was sealed, and then heated at 70 ° C for 5 hours, followed by heating in an oven at 100 ° C. The mixture was hardened in 3 hours to obtain a mutual intrusion into the polymer network structure. The obtained intrusive polymer mesh structure was released from the glass, dried at 50 ° C for 12 hours, and then vacuum dried at 100 ° C for 12 hours, and the components which can be removed were removed under reduced pressure.

The center portion in the thickness direction of the mutually invading polymer mesh structure was subjected to slicing and surface grinding to obtain a sheet having a thickness of 2 mm. When the No. 1 shaped test piece was punched from the center of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 10.3 MPa and 260%, respectively. Further, when the No. 1 shaped test piece was punched from the end of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 9.2 MPa and 190%, respectively. Subsequently, a circle having a diameter of 600 mm was punched, and then ground to a thickness of 2 mm, and a groove having a width of 2 mm, a depth of 0.6 mm, and a pitch of 40 mm was formed on one side to form a polishing pad. The polishing pad had an apparent density of 0.80 g/cm 3 and the closed cells had an average bubble diameter of 39 μm. It was observed that there were 350/mm 2 openings from the bubbles on the surface.

When the polishing evaluation was performed, the polishing rates of the first sheet and the tenth sheet were each 1700 Å/min and 1650 Å/min, and the in-plane uniformity was 16% and 17%, respectively. The polishing rate after grinding 100 sheets was 1,400 angstroms/minute, and the in-plane uniformity was 28%.

(Comparative Example 5)

Except that the immersion conditions were 60° C., the same procedure as in Comparative Example 1 was carried out, and after the polyurethane structural body was immersed in the radical polymerizable composition for 5 hours, the radical polymerizable composition was hardened before the total amount of the immersion. The cured product of the polyurethane shaped article and the radically polymerizable composition cannot be integrated.

(Example 9)

The following radical polymerizable composition was prepared, and when the polyurethane molded article produced in Comparative Example 4 was immersed at 40 ° C for 3 days, the radical polymerizable composition was impregnated with the polyurethane shaped article in its entirety. The weight ratio of the polyurethane shaped article to the radically polymerizable composition was 100/120.

Methyl methacrylate 300 parts by weight of azobisisobutyronitrile 1.5 parts by weight of 2,6-di-tert-butyl-4-methylphenol 0.2 parts by weight

The urethane molded body expanded by the immersion was sandwiched between two glass plates, and the periphery was sealed, and then heated at 70 ° C for 5 hours, followed by heating in an oven at 100 ° C. The mixture was hardened in 3 hours to obtain a mutual intrusion into the polymer network structure. After the obtained mutually invading polymer mesh structure was released from the glass, the center portion in the thickness direction was sliced and surface-ground to obtain a sheet having a thickness of 2 mm.

When the No. 1 shaped test piece was punched from the center of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 10.3 MPa and 260%, respectively. Further, when the No. 1 shaped test piece was punched from the end of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 10.2 MPa and 260%, respectively.

The above-mentioned sheet was punched into a circle having a diameter of 600 mm, and ground to a thickness of 2 mm, and a groove having a width of 2 mm, a depth of 0.6 mm, and a pitch of 40 mm was formed on one side to form a polishing pad. The polishing pad had an apparent density of 0.80 g/cm 3 and the closed cells had an average bubble diameter of 39 μm. It was observed that there were 350/mm 2 openings from the bubbles on the surface.

When the polishing evaluation was performed, the polishing rates of the first sheet and the tenth sheet were each 1700 Å/min and 1650 Å/min, and the in-plane uniformity was 8% and 8%, respectively. The polishing rate after grinding 100 sheets was 1,700 angstroms/minute, and the in-plane uniformity was 8%.

(Embodiment 10)

The following raw material composition was added to each of the first raw material tank and the second raw material tank of the RIM molding machine, and was injected into a mold to be cured to obtain a polyurethane molded article of 850 mm × 850 mm and a thickness of 12 mm. The apparent density of the obtained polyurethane shaped article was 0.77 g/cm 3 , and closed cells having an average cell diameter of 32 μm were observed.

<First raw material tank> Polypropylene glycol 85 parts by weight Diethylene glycol 15 parts by weight Tin octoate 0.5 parts by weight Antimony-based bubble stabilizer 3 parts by weight Purified water 0.3 parts by weight 2,6-di-t-butyl-4- Methyl phenol 0.1 parts by weight

<Second raw material tank> diphenylmethane diisocyanate 120 parts by weight

Then, the following radical polymerizable composition was prepared, and after immersing the above-mentioned polyurethane shaped body at 40 ° C for 3 days, the radically polymerizable composition was immersed in the entire polyurethane shaped body. The weight ratio of the polyurethane shaped article to the radically polymerizable composition was 100/120.

Methyl methacrylate 300 parts by weight of azobisisobutyronitrile 1.5 parts by weight of 2,6-di-t-butyl 4-methylphenol 0.1 parts by weight

The urethane molded body expanded by the immersion was sandwiched between two glass plates, and the periphery was sealed, and then heated at 70 ° C for 5 hours, followed by heating in an oven at 100 ° C. The mixture was hardened in 3 hours to obtain a mutual intrusion into the polymer network structure. After the obtained mutually invading polymer mesh structure was released from the glass, the center portion in the thickness direction of the mutually invaded polymer mesh structure was subjected to slicing and surface grinding to obtain a sheet having a thickness of 2 mm.

When the No. 1 shaped test piece was punched from the center of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 10.3 MPa and 260%, respectively. Further, when the No. 1 shaped test piece was punched from the end of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 10.3 MPa and 260%, respectively.

To the above-mentioned sheet, a circle having a diameter of 600 mm was punched, and a groove having a grid shape of 2 mm in width, 0.6 mm in depth, and 40 mm in pitch was formed on one surface to prepare a polishing pad. The polishing pad had an apparent density of 0.80 g/cm 3 and the closed cells had an average bubble diameter of 39 μm. It was observed that there were 350/mm 2 openings from the bubbles on the surface.

When the polishing evaluation was performed, the polishing rates of the first sheet and the tenth sheet were each 1700 Å/min and 1700 Å/min, and the in-plane uniformity was 8% and 8%, respectively. The polishing rate after grinding 100 sheets was 1,700 angstroms/min, and the in-plane uniformity was 7%.

(Example 11)

The following raw material composition was added to each of the first raw material tank and the second raw material tank of the RIM molding machine, and after the nitrogen gas was placed in the first raw material tank, it was poured into a mold and hardened to obtain a mixture of 850 mm × 850 mm and a thickness of 12 mm. A urethane shaped body. The apparent density of the obtained polyurethane shaped article was 0.82 g/cm 3 , and independent bubbles having an average cell diameter of 28 μm were observed.

<1st raw material tank> polypropylene glycol 85 parts by weight of ethylene glycol 1.5 parts by weight of α-methylstyrene dimer 0.4 parts by weight of 2,6-di-tert-butyl-4-methylphenol 0.1 parts by weight Tin octoate 0.5 parts by weight of hydrazine bubble stabilizer 3 parts by weight of purified water 0.3 parts by weight

<Second raw material tank> diphenylmethane diisocyanate 120 parts by weight

Next, the following radical polymerizable composition was prepared, and after immersing the above-mentioned polyurethane shaped body at 20 ° C for 7 days, the radically polymerizable composition was immersed in the entire polyurethane shaped body. The weight ratio of the polyurethane shaped article to the radically polymerizable composition was 100/140.

Methyl methacrylate 300 parts by weight of azobisisobutyronitrile 0.5 parts by weight

The urethane molded body expanded by the immersion was sandwiched between two glass plates, and the periphery was sealed, and then heated at 70 ° C for 5 hours, followed by heating in an oven at 100 ° C. The mixture was hardened in 3 hours to obtain a mutual intrusion into the polymer network structure. The obtained intrusive polymer mesh structure was released from the glass, and the weight was measured. Further, the mixture was dried at 50 ° C for 12 hours, then dried at 100 ° C for 12 hours, and further dried at room temperature for 12 hours. Immediately after the weight was measured, the weight was not reduced as compared with that before drying.

The solid state NMR (nuclear magnetic resonance) method was used to measure the relaxation time of the intrusion into the polymer network structure, and it was confirmed that the PMMA has a structure in which PMMA is dispersed at a level of several tens of nanometers or less, and the polyurethane is urethane. The two polymer chains of the ester and PMMA invade each other, and the polymer chains are entangled with each other. In other words, the relaxation time from the mutual invasion into the polymer mesh structure is longer than the relaxation time of the polyurethane molded article alone and the methyl methacrylate polymer alone, and it is confirmed that the mutually invading polymer mesh structure is formed. .

The center portion in the thickness direction of the mutually invading polymer mesh structure was subjected to slicing and surface grinding to obtain a sheet having a thickness of 2 mm. When the No. 1 shaped test piece was punched from the center of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 16.6 MPa and 310%, respectively. Further, when the No. 1 shaped test piece was punched from the end of the sheet and the tensile breaking strength and the tensile elongation at break were measured, they were 16.5 MPa and 300%, respectively.

Next, the weight ratio of the polyurethane to the PMMA was calculated for the above-mentioned sheet. As a result, the weight ratio of the polyurethane in 400 small pieces was 43.0%, the minimum value was 41.6%, and the maximum value was 44.5%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/132.5.

Next, the above-mentioned sheet was punched into a circle having a diameter of 600 mm, and a groove having a lattice shape of 1.5 mm in width, 0.5 mm in depth, and 30 mm in pitch was formed on one surface to prepare a polishing pad. The apparent density of the polishing pad was 0.84 g/cm 3 and the average bubble diameter of the closed cells was 34 μm. It was observed that there were 392/mm 2 openings from the bubbles on the surface.

When the polishing evaluation was performed, the polishing rates of the first sheet and the 20th sheet were each 1900 Å/min and 1900 Å/min, and the in-plane uniformity was 7% and 8%, respectively. The polishing rate after grinding 500 sheets was 1,850 angstroms/minute, and the in-plane uniformity was 8%. Moreover, the flattening property is flattened and it takes about 120 seconds of polishing.

(Embodiment 12)

The portions in the thickness direction of the polymer mesh structure of Example 11 which were in the thickness direction of 1/5 and 4/5 were sliced and surface-ground to obtain a sheet having a thickness of 2 mm. When the No. 1 shaped test piece was punched from the center of the film and the tensile breaking strength and the tensile elongation at break were measured, each was tensile fracture strength of 17.5 MPa and tensile elongation at break of 330%, and tensile fracture. The strength is 17.3 MPa and the tensile elongation at break is 330%.

Next, the weight ratio of the polyurethane of the sum of the polyurethane and the PMMA was calculated from the sheet having a thickness of 2 mm obtained from the 1/5 portion in the thickness direction. As a result, the weight ratio of the polyurethane in 400 small pieces was 40.4%, the minimum value was 39.0%, and the maximum value was 41.8%. The ratio of the polyurethane shaped body to the ethylenically unsaturated compound polymer was 100/147.5.

In Example 11 and Example 12, tensile tensile strength and tensile elongation at break of a tensile test piece having a thickness of about 2 mm obtained from the same mutual intrusion into the polymer mesh structure, in the sheet and in the sheet The difference between the two is small. Further, the distribution in the sheet of the weight ratio of the polyurethane of Example 11 and Example 12 was 43.0 ± 1.5 (%) and 40.4 ± 1.4 (%), respectively, and the composition distribution width in the sheet surface was small. It is known that the composition in the thickness direction is also uniform. It has been found that by adding a polymerization inhibitor, in particular, the in-plane uniformity of the sheet can be improved.

As described above, in the examples and the comparative examples, the polymer mesh structure was invaded, and the apparent density, the average cell diameter of the closed cells, the number of cells, and the like were the same, but the mechanical properties were different. When the mutually invading polymer mesh structure of the embodiment is compared with the material of the comparative example, the tensile breaking strength and the tensile elongation at break are high, and the tensile breaking strength or the tensile elongation at break is small and uniform according to the position distribution. Higher. Further, the polishing pad obtained by invading the polymer mesh structure from each other in the examples has high in-plane uniformity during CMP polishing and excellent flatness characteristics, and can greatly improve the durability.

Industrial use possibility

The polishing pad of the present invention can be used for polishing a semiconductor substrate such as a tantalum wafer, an optical component such as a lens, an electronic material such as a magnetic head or a hard disk, or the like. In particular, when a semiconductor wafer for polishing a workpiece is polished by a chemical mechanical polishing (CMP) technique for the purpose of planarizing a semiconductor wafer, it is used as a polishing pad.

Claims (17)

A method for producing a mutually invading polymer mesh structure, which comprises a method for producing an intrusive polymer network structure comprising an impregnation process and a polymerization process, wherein the dipping process is free of an ethylenically unsaturated compound and a radical polymerization initiator The base polymerizable composition impregnates the polymer molded body; and the polymerization process is a process of polymerizing the ethylenically unsaturated compound in an expanded state of the polymer molded body impregnated with the radical polymerizable composition, wherein A chain transfer agent and/or a radical polymerization inhibitor is added to the radical polymerizable composition and/or the polymer molded body before the process of impregnating the polymer molded body with the radical polymerizable composition. A method for producing a mutually invading polymer mesh structure according to the first aspect of the invention, wherein a chain transfer agent and/or a radical polymerization inhibitor are added to the polymer molded article. The method for producing a mutually invading polymer network structure according to the first aspect of the invention, wherein the chain transfer agent and/or the radical polymerization inhibitor has a molecular weight of 350 or less. The method for producing a mutually invading polymer network structure according to the first aspect of the invention, wherein the chain transfer agent is one or more selected from the group consisting of a thiol having an alkyl group having 3 to 12 carbon atoms and an aromatic hydrocarbon chain transfer agent. Compound. A method for producing a mutually invading polymer mesh structure according to the second aspect of the patent application, wherein the polymer molded body is 100% by weight or more 0.01 to 20% by weight of a chain transfer agent is added to the polymer molded body. The method for producing a mutually invasive mesh structure according to the first aspect of the invention, wherein the radical polymerization inhibitor has one or more compounds having an aromatic ring and at least one or more hydroxyl groups. The method for producing a mutually invasive mesh structure according to the first aspect of the invention, wherein the radical polymerization inhibitor does not substantially contain an organic solvent. The method for producing a mutually invasive mesh structure according to the first aspect of the invention, wherein the ethylenically unsaturated compound is selected from the group consisting of methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and methacrylic acid. a compound of a third butyl ester. The method for producing a mutually invasive mesh structure according to the first aspect of the invention, wherein the ethylenically unsaturated compound is polymerized in the presence of oxygen or a gas containing oxygen. A method for producing a polishing pad comprising the process of producing a polishing pad by mutually invading a polymer mesh structure obtained by a method of mutually invading a polymer mesh structure according to any one of claims 1 to 9 . A polishing pad comprising a polymer in which a polymer molded body and an ethylenically unsaturated compound are mutually invaded into a polymer mesh structure, and is a polishing pad having a thickness of 1 mm or more and a diameter of 300 mm or more, wherein the polishing pad is relative to the polymer. When the average weight ratio of the molded article and the ethylenically unsaturated compound polymer is X (%), the weight ratio of the polymer molded body at any position of the polishing pad is X ± 3 ( %)In the range. The polishing pad of claim 11, wherein the tensile breaking strength is 13 MPa or more. The polishing pad of claim 11, wherein the tensile elongation at break is 150% or more. For example, the polishing pad of claim 11 has independent bubbles having an average bubble diameter of 10 to 230 μm. For example, the polishing pad of claim 11 has an apparent density of 0.2 to 1.1 g/cm 3 . For example, in the polishing pad of claim 11, wherein the weight ratio of the polymer molded body to the ethylenically unsaturated compound polymer is 100/5 to 100/300. A method of manufacturing a semiconductor device, comprising the process of polishing a surface of a semiconductor substrate using the polishing pad of claim 11 of the patent application.