JP2004009156A - Polishing pad and multiple layer type polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing pad for chemical mechanical polishing having a recessed part of a specified shape on a polishing surface side and capable of restraining a scratch on a polished surface. <P>SOLUTION: This polishing pad has a plurality of ring grooves on the polishing surface side, and surface roughness of an inner surface of the groove is less than 20μm and in particular less than 10μm. Additionally depth of this groove is more than 0.1mm and in particular more than 0.2∼2.0mm, width is more than 0.1mm and in particular 2.0∼3.0mm and it is favorable that minimal distance between the adjacent grooves is more than 0.05mm and in particular 0.1∼10mm. Furthermore, it is favorable that this polishing pad has a non-water soluble matrix material containing a bridged polymer such as bridged 1, 2-polybutadiene and a non-water soluble particulate made of polysaccharide dispersed in this non water soluble matrix material. Additionally, this polishing pad can be made into a multi-layer type polishing pad on the back surface side of which a flexible supporting layer made of a resin foaming body etc. is arranged. <P>COPYRIGHT: (C)2004,JPO

Description

【００５０】
表面粗さの測定結果から、比較例１の研磨パッドでは、溝の内面は凹凸が激しく、不均質であることが分かる。また、図５によると大きな凸部が認められる。更に、「詳説　半導体ＣＭＰ技術」（土井俊郎編著、株式会社工業調査会出版、初版第１刷）の１１４ページに掲載されている図３．６３は、比較例１で用いた研磨パッドと同じ発泡ポリウレタン製の研磨パッド（ロデール・ニッタ株式会社製、商品名「ＩＣ１０００」）の走査型電子顕微鏡による写真である。この写真からも、実施例１による図４に比べて大きな凹凸が溝内に存在していることが分かる。
【００５１】
また、表１の結果より、この研磨パッドにより研磨した被研磨面には、スクラッチ及び異物が認められた。また、ドレッシング後のポアの状態も一部が塞がれ、開口していなかった。特にドレッシングにより塞がれ易い溝の開口部周辺のポアはほとんど塞がっていた。更に、実施例１に対する研磨速度は１／４、また、実施例２に対する研磨速度は１／５と大きく劣っていることが分かる。これは研磨時に異物等によりポアが塞がれていたためであると考えられる。
【００５２】
これに対して、実施例１及び２の研磨パッドでは、溝内部の側面及び底面ともに表面粗さが非常に小さく、平滑である。このことは図４からも確認できる。そのため、被研磨面にはスクラッチがほとんど認められず、異物もほとんど認められなかった。更に、ドレッシング後においてもポアはほとんど完全に開口しており、特に溝の開口部周辺のポアもすべて開口していた。また、研磨速度は比較例１に対して実施例１は４倍、実施例２は５倍も早いものであった。これは、ポアが異物によって塞がれていないためであると考えられる。
【００５３】
【発明の効果】
本発明の研磨パッドによれば、溝内部で発生する異物等によるスクラッチを効果的に抑えられる。
また、溝が特定の深さ、幅及び間隔を有する場合は、スクラッチの発生がより確実に抑えられる。
更に、架橋重合体を含有する非水溶性マトリックスと、水溶性粒子とを有する場合は、溝の内面の表面粗さを２０μｍ以下に容易に抑えることができ、ドレッシングによってもポアが塞がれず、スラリーが十分に保持され、研磨速度を大きくすることができる。
また、溝が切削及び／又は型成形により形成された場合は、溝内面の表面粗さを容易に小さくすることができ、スクラッチの発生をより十分に抑えることができる。
本発明の複層型研磨パッドによれば、溝内部で発生する異物等によるスクラッチを効果的に抑えられるとともに、パッドの研磨面とウェハ等の被研磨面とを十分に密着させることができ、研磨速度を向上させることもできる。
更に、溝又は貫通孔が特定の深さ、幅及び間隔を有する場合は、スクラッチの発生がより確実に抑えられる。
また、研磨層が架橋重合体を含有する非水溶性マトリックスと、水溶性粒子とを有する場合は、研磨層の溝又は貫通孔の内面の表面粗さを２０μｍ以下に容易に抑えることができ、ドレッシングによってもポアが塞がれず、スラリーが十分に保持され、研磨速度を大きくすることができる。
更に、溝又は貫通孔が切削及び／又は型成形により形成された場合は、溝内面の表面粗さを容易に小さくすることができ、スクラッチの発生をより十分に抑えることができる。
【図面の簡単な説明】
【図１】本発明の研磨パッド及び複層型研磨パッドの一例の模式的な平面図である。
【図２】本発明の研磨パッド及び複層型研磨パッドの一例の模式的な平面図である。
【図３】本発明の研磨パッド及び複層型研磨パッドの溝を含む一部横断面の模式図である。
【図４】実施例１の研磨パッドの一部断面の顕微鏡写真による説明図である。
【図５】比較例１の研磨パッドの一部断面の顕微鏡写真による説明図である。
【符号の説明】
１；研磨パッド又は複層型研磨パッド、１２；環状の溝又は環状の貫通孔、２１；ピッチ、２２；溝又は貫通孔の幅、２３；隣り合う溝の間の距離。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polishing pad and a multilayer polishing pad. More specifically, the present invention relates to a polishing pad having a groove of a specific shape on a polishing surface side. The present invention is widely used in the manufacture of semiconductor devices. Particularly, it is suitable for chemical mechanical polishing of the surface of a semiconductor wafer or the like.
[0002]
[Prior art]
In recent years, as a polishing method capable of forming a surface having excellent flatness, chemical mechanical polishing (CMP) has attracted attention. In CMP, polishing is performed by sliding a slurry, which is an aqueous dispersion in which abrasive grains are dispersed on the polishing pad surface, from above while sliding the polishing pad and the surface to be polished. In this CMP, it is known that a polishing result is greatly affected by properties and characteristics of a polishing pad.
[0003]
Techniques for improving the polishing rate and the polishing result by providing grooves on the surface of the polishing pad are disclosed in JP-A-11-70463, JP-A-8-216029, JP-A-8-39423, and the like. Have been. However, there are cases where scratches cannot be sufficiently prevented even by using these techniques.
Further, as a polishing pad capable of forming pores without using a foam, Japanese Patent Application Laid-Open No. 8-500622, JP-A-2000-34416, JP-A-2000-33552, JP-A-2001-334455, etc. The disclosed technology is known. However, even if these techniques are used, it may not be possible to prevent the pores from being clogged during polishing, or it may not be possible to prevent the pores from being clogged after dressing, which may not be able to sufficiently improve the polishing rate. Further, the slurry may not be sufficiently uniformly distributed on the polishing pad in some cases, whereby the polishing rate cannot be sufficiently improved, and a sufficiently uniform surface to be polished may not be obtained.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to solve the conventional problems described above, and an object of the present invention is to provide a polishing pad and a multilayer polishing pad that can particularly effectively suppress the occurrence of scratches.
[0005]
[Means for Solving the Problems]
The polishing pad of the present invention has a plurality of annular grooves on the polishing surface side, and the inner surface of the grooves has a surface roughness of 20 μm or less, and is used for chemical mechanical polishing.
Further, the polishing pad can be a polishing pad in which the grooves are arranged concentrically.
Further, the groove may be a polishing pad having a depth of at least 0.1 mm, a width of at least 0.1 mm, and a minimum distance between adjacent grooves of at least 0.05 mm.
Further, a polishing pad having a water-insoluble matrix containing a crosslinked polymer and water-soluble particles dispersed in the water-insoluble matrix can be obtained.
Further, the groove may be a polishing pad formed by cutting and / or molding.
[0006]
The multilayer polishing pad of the present invention has a polishing layer having a plurality of annular grooves or a plurality of annular through holes which are open to the polishing surface side and whose inner surface has a surface roughness of 20 μm or less; And a support layer disposed on the back surface side, wherein the support layer is used for chemical mechanical polishing.
Further, the groove or the through-hole may be a multi-layered polishing pad arranged concentrically.
Further, the groove or the through hole has a depth of at least 0.1 mm, a width of at least 0.1 mm, and a minimum distance between adjacent grooves or the through holes of at least 0.05 mm. It can be.
Further, the polishing layer can be a multilayer polishing pad having a water-insoluble matrix containing a crosslinked polymer and water-soluble particles dispersed in the water-insoluble matrix.
Further, the groove or the through hole may be a multi-layer polishing pad formed by cutting and / or molding.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The “groove” is opened on the polishing surface side of the polishing pad. This groove has a function of holding the slurry supplied during polishing and distributing the slurry more evenly to the polishing surface. Further, it has a function of temporarily retaining waste such as wear debris and used slurry generated by polishing, and serving as a discharge path for discharging the waste to the outside.
[0008]
The planar shape of the groove is not particularly limited, and may be, for example, a circle, a polygon (a triangle, a square, a pentagon, etc.), an ellipse, or the like. The number of grooves formed on the polishing pad is not particularly limited as long as it is two or more. Further, the arrangement of these grooves is not particularly limited. For example, those in which each groove is arranged concentrically (concentrically or the like) (see FIG. 1) and those in which each groove is arranged eccentrically (see FIG. 2) One in which a plurality of other annular grooves are arranged inside the polishing surface surrounded by one annular groove can be used. Among these, the one in which each groove is arranged concentrically is preferable, and the polishing pad in which the grooves are arranged concentrically (a state in which a plurality of circular grooves are arranged concentrically) is more preferable. A polishing pad arranged concentrically has an excellent function as compared with other polishing pads. In addition, the concentric shape further enhances these functions, and facilitates the formation of the groove.
On the other hand, the cross-sectional shape of the groove in the width direction is not particularly limited.
[0009]
Although the size of the groove is not particularly limited, for example, the width of the groove (22 in FIG. 3) may be 0.1 mm or more (more preferably 0.1 to 5 mm, further preferably 0.2 to 3 mm). preferable. Usually, it tends to be difficult to form a groove having a width of less than 0.1 mm. Also, the depth of the groove is preferably 0.1 mm or more (more preferably 0.1 to 2.5 mm, more preferably 0.2 to 2.0 mm). If the depth of the groove is less than 0.1 mm, the life of the polishing pad becomes excessively short, which is not preferable. Further, the interval between the grooves is preferably such that the minimum distance (23 in FIG. 3) between the adjacent grooves is 0.05 mm or more (more preferably 0.05 to 100 mm, further preferably 0.1 to 10 mm). . It tends to be difficult to form a groove whose minimum distance is less than 0.05 mm. The pitch (21 in FIG. 3) which is the sum of the width of the groove and the distance between adjacent grooves is 0.15 mm or more (more preferably 0.15 to 105 mm, further preferably 0.6 to 13 mm, particularly It is preferably from 0.5 to 2.2).
Each of the above preferred ranges can be a combination of each. That is, for example, it is preferable that the width is 0.1 mm or more, the depth is 0.1 mm or more, and the minimum distance is 0.05 mm or more, and the width is 0.1 to 5 mm and the depth is 0.1 to 2. It is more preferable that the minimum distance is 5 mm and the minimum distance is 0.15 to 105 mm, the width is 0.2 to 3 mm, the depth is 0.2 to 2.0 mm, and the minimum distance is 0.6 to 13 mm. More preferred.
[0010]
The “surface roughness” of the inner surface of the groove is 20 μm or less (preferably 15 μm or less, more preferably 10 μm or less, and usually 0.05 μm or more). When the surface roughness is 20 μm or less, scratches during polishing can be effectively prevented. The surface roughness is a value measured by a measuring method described later, and is at least before the polishing pad of the present invention is used.
[0011]
When the surface roughness of the inner surface of the groove is 20 μm or less, there is no large unevenness. When there are large irregularities, particularly large convex portions (for example, formed of uncut portions generated during the formation of grooves) are detached during polishing, which causes scratches. Further, foreign matter formed by compression of the detached convex portion due to pressure, frictional heat, or the like during polishing, and the detached convex portion and polishing debris, solid content in the slurry, etc. act. In some cases, scratches may also occur due to foreign matter or the like that is formed. Also, at the time of dressing, these projections may come off and cause similar problems.
When the surface roughness is 20 μm or less, scratches can be prevented, and in addition, the function as the grooves, particularly, the function of distributing the slurry to the polishing surface and the function of discharging waste to the outside are exhibited particularly efficiently. You.
[0012]
The surface roughness was determined from the three average surface roughnesses obtained by measuring the average surface roughness using a measuring instrument or the like capable of measuring the surface roughness in three different visual fields on the surface of the polishing pad before use. Average value. The measuring instrument used is not particularly limited. For example, a three-dimensional surface structure analysis microscope, a scanning laser microscope, an optical surface roughness measuring instrument such as an electron beam surface portable analyzer, a stylus type surface roughness meter, etc. A contact surface roughness meter can be used.
[0013]
Note that, in addition to these annular grooves, grooves and recesses of other shapes may be provided on the polishing surface. Examples of the groove having another shape include, for example, a groove whose planar shape is linear in the radial direction of the polishing pad (usually intersecting with an annular groove). Examples of the concave portion include a concave portion (dot pattern) that is opened in a planar shape such as a circle or a polygon.
[0014]
The polishing pad having the groove may be made of any material as long as it can function as a polishing pad. However, among the functions as a polishing pad, it is particularly preferable that pores having a function of retaining slurry at the time of polishing and temporarily retaining polishing wastes be formed by the time of polishing. For this reason, it is preferable to provide a water-soluble particle and a water-insoluble matrix in which the water-soluble particles are dispersed, or a water-insoluble matrix material (foam or the like) in which cavities are dispersed. Among them, in the former, the water-soluble particles come into contact with the aqueous medium portion of the slurry (containing the medium portion and the solid portion) at the time of polishing, and dissolve or swell to be eliminated. Then, the slurry can be held in the pores formed by the desorption. On the other hand, the latter can hold the slurry in pores that are preformed as cavities.
[0015]
The material constituting the `` water-insoluble matrix '' is not particularly limited, but is usually formed of an organic material because it can be easily formed into a predetermined shape and properties, and can have appropriate hardness and appropriate elasticity. Used. As the organic material, a thermoplastic resin, an elastomer, a rubber (crosslinked rubber), a cured resin (a thermosetting resin, a photocurable resin, etc., a resin cured by heat, light, or the like) or the like may be used alone or in combination. Can be.
[0016]
Among them, as the thermoplastic resin, 1,2-polybutadiene resin, polyolefin resin such as polyethylene, polystyrene resin, polyacrylic resin {(meth) acrylate resin, etc.}, vinyl ester resin (excluding acrylic resin) , A polyester resin, a polyamide resin, a fluororesin such as polyvinylidene fluoride, a polycarbonate resin, a polyacetal resin, and the like.
[0017]
Examples of the elastomer include diene elastomers such as 1,2-polybutadiene, styrene elastomers such as polyolefin elastomer (TPO), styrene-butadiene-styrene block copolymer (SBS), and hydrogenated block copolymer (SEBS) thereof. Examples include thermoplastic elastomers such as elastomers, thermoplastic polyurethane elastomers (TPU), thermoplastic polyester elastomers (TPEE), and polyamide elastomers (TPAE), silicone resin elastomers, and fluororesin elastomers.
[0018]
Examples of the rubber include conjugated diene rubbers such as butadiene rubber (high cis butadiene rubber, low cis butadiene rubber, etc.), isoprene rubber, styrene-butadiene rubber, styrene-isoprene rubber, and acrylonitrile-butadiene rubber. Other rubbers such as nitrile rubber, acrylic rubber, ethylene-propylene rubber, ethylene-α-olefin rubber such as ethylene-propylene-diene rubber and butyl rubber, and silicone rubber and fluorine rubber can be mentioned. .
Examples of the cured resin include urethane resins, epoxy resins, acrylic resins, unsaturated polyester resins, polyurethane-urea resins, urea resins, silicon resins, phenol resins, and vinyl ester resins. it can.
These organic materials may be modified with an acid anhydride group, a carboxyl group, a hydroxyl group, an epoxy group, an amino group, or the like. By the modification, the affinity with the water-soluble particles and the slurry described below can be adjusted.
These organic materials may be used alone or in combination of two or more.
[0019]
Further, these organic materials may be a crosslinked polymer in which a part or all thereof is crosslinked, or may be a non-crosslinked polymer. Therefore, the water-insoluble matrix may be composed of only a crosslinked polymer, may be a mixture of a crosslinked polymer and a noncrosslinked polymer, or may be composed of only a noncrosslinked polymer. However, it is preferable to contain a crosslinked polymer (only a crosslinked polymer or a mixture of a crosslinked polymer and a non-crosslinked polymer). By containing the cross-linked polymer, the surface roughness of the inner surface of the groove can be easily reduced to 20 μm or less, and the water-insoluble matrix is provided with an elastic recovery force, and the displacement due to shear stress applied to the polishing pad during polishing is reduced. Can be suppressed. In addition, it is possible to effectively prevent the water-insoluble matrix from being excessively stretched during the polishing and the dressing, resulting in plastic deformation and filling of the pores, and the polishing pad surface being excessively fuzzed. Therefore, pores are efficiently formed even during dressing, and the retention of slurry during polishing can be prevented from lowering. In addition, there is little fluffing and the polishing flatness is not impaired. The method for performing the above-mentioned crosslinking is not particularly limited, and the crosslinking can be performed by chemical crosslinking using an organic peroxide, sulfur, a sulfur compound or the like, radiation crosslinking by electron beam irradiation or the like.
[0020]
As the crosslinked polymer, among the above organic materials, a crosslinked rubber, a cured resin, a crosslinked thermoplastic resin, a crosslinked elastomer, and the like can be used. Further, among these, crosslinked thermoplastic resins and / or crosslinked elastomers are preferable because they are stable to strong acids and strong alkalis contained in many slurries and have little softening due to water absorption. Among the crosslinked thermoplastic resins and crosslinked elastomers, those crosslinked using an organic peroxide are particularly preferable, and crosslinked 1,2-polybutadiene is more preferable. Thus, a groove having a surface roughness of 20 μm or less can be easily formed.
[0021]
Although the content of these crosslinked polymers is not particularly limited, it is 30% by volume or more (more preferably 50% by volume or more, even more preferably 70% by volume or more, or 100% by volume) of the whole water-insoluble matrix. Preferably, there is. When the content of the crosslinked polymer in the water-insoluble matrix is less than 30% by volume, the effect of containing the crosslinked polymer may not be sufficiently exhibited.
[0022]
The water-insoluble matrix containing a crosslinked polymer is an elongation remaining after breaking when a test piece made of the water-insoluble matrix is broken at 80 ° C. in accordance with JIS K6251 (hereinafter simply referred to as “residual elongation at break”). ) Can be set to 100% or less. That is, the total distance between the marked lines after breaking is not more than twice the distance between the marked lines before breaking. This residual elongation at break is more preferably at most 30% (more preferably at most 10%, particularly preferably at most 5%, usually at least 0%). When the residual elongation at break exceeds 100%, fine pieces scraped or elongated from the polishing pad surface during polishing and surface renewal tend to easily block the pores, which is not preferable. The “residual elongation at break” refers to a dumbbell-shaped No. 3 test piece in accordance with JIS K 6251 “Tensile test method for vulcanized rubber”, a tensile speed of 500 mm / min, and a tensile test at a test temperature of 80 ° C. When the test piece is broken, the elongation is obtained by subtracting the distance between the mark lines before the test from the total distance from each mark line to the fracture portion of the test piece divided by breaking. Further, in actual polishing, heat is generated by sliding, so that the test is performed at a temperature of 80 ° C.
[0023]
The “water-soluble particles” are particles that are released from the water-insoluble matrix by coming into contact with a slurry that is an aqueous dispersion in the polishing pad. This desorption may be caused by dissolving by contact with water or the like contained in the slurry, or may be caused by swelling and gelation containing the water or the like. Further, the dissolution or swelling may be caused not only by water but also by contact with an aqueous mixed medium containing an alcoholic solvent such as methanol.
[0024]
The water-soluble particles have the effect of increasing the indentation hardness of the polishing pad in the polishing pad, in addition to the effect of forming pores. That is, for example, the polishing pad of the present invention can have a Shore D hardness of 35 or more (more preferably 50 to 90, further preferably 60 to 85, usually 100 or less) by containing water-soluble particles. When the Shore D hardness is 35 or more, the pressure that can be applied to the object to be polished can be increased, and accordingly, the polishing rate can be improved. In addition, high polishing flatness is obtained. Therefore, it is particularly preferable that the water-soluble particles are solid bodies capable of securing sufficient indentation hardness in the polishing pad.
[0025]
The material constituting the water-soluble particles is not particularly limited, and examples thereof include organic water-soluble particles and inorganic water-soluble particles. Organic water-soluble particles include sugars (polysaccharides such as starch, dextrin and cyclodextrin, lactose, mannitol, etc.), celluloses (hydroxypropylcellulose, methylcellulose, etc.), proteins, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid And polyethylene oxide, water-soluble photosensitive resin, sulfonated polyisoprene, sulfonated polyisoprene copolymer and the like. Further, examples of the inorganic water-soluble particles include those formed from potassium acetate, potassium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium chloride, potassium bromide, potassium phosphate, magnesium nitrate, and the like. These water-soluble particles can be used alone or in combination of two or more. Furthermore, one kind of water-soluble particles made of a predetermined material may be used, or two or more kinds of water-soluble particles made of different materials may be used.
[0026]
Further, the average particle size of the water-soluble particles is preferably 0.1 to 500 μm (more preferably 0.5 to 100 μm). That is, the pore size is preferably 0.1 to 500 μm (more preferably 0.5 to 100 μm). If the average particle size of the water-soluble particles is less than 0.1 μm, the size of the pores formed will be smaller than the abrasive grains used, and it tends to be difficult to obtain a polishing pad that can sufficiently hold the slurry. On the other hand, if it exceeds 500 μm, the size of the formed pores becomes excessive, and the mechanical strength and polishing rate of the obtained polishing pad tend to decrease.
[0027]
As for the content of the water-soluble particles, when the total of the water-insoluble matrix and the water-soluble particles is 100% by volume, the water-soluble particles are 10 to 90% by volume (more preferably 15 to 60% by volume, still more preferably). Is preferably 20 to 40% by volume). When the content of the water-soluble particles is less than 10% by volume, pores are not sufficiently formed in the obtained polishing pad, and the polishing rate tends to decrease. On the other hand, when the content of the water-soluble particles exceeds 90% by volume, it tends to be difficult to sufficiently prevent swelling or dissolution of the water-soluble particles present inside the polishing pad in the obtained polishing pad. It is difficult to maintain the hardness and the mechanical strength at appropriate values.
[0028]
It is preferable that the water-soluble particles are water-soluble only when exposed to the surface layer in the polishing pad, absorb moisture inside the polishing pad, and do not swell. For this reason, the water-soluble particles can have an outer shell that suppresses moisture absorption at least at a part of the outermost part. This outer shell may be physically adsorbed to the water-soluble particles, may be chemically bonded to the water-soluble particles, or may be in contact with the water-soluble particles by both. Examples of a material forming such an outer shell include epoxy resin, polyimide, polyamide, and polysilicate. The above effect can be sufficiently obtained even if this outer shell is formed only in a part of the water-soluble particles.
[0029]
The water-insoluble matrix may contain a compatibilizer in order to control the affinity with the water-soluble particles and the dispersibility of the water-soluble particles in the water-insoluble matrix. Examples of the compatibilizer include polymers modified with acid anhydride groups, carboxyl groups, hydroxyl groups, epoxy groups, oxazoline groups and amino groups, block copolymers, random copolymers, and various nonionics. Surfactants, coupling agents and the like can be mentioned.
[0030]
Further, the water-insoluble matrix is, in addition to the above-mentioned compatibilizer, abrasive grains, oxidizing agents, alkali metal hydroxides, acids, pH adjusters, surfactants and anti-scratch agents conventionally contained in the slurry. And the like, or one or more thereof. Thus, it becomes possible to perform polishing by supplying only water during polishing.
Examples of the abrasive grains include particles made of silica, alumina, ceria, zirconia, titania, and the like. One or more of these can be used.
Examples of the oxidizing agent include organic peroxides such as hydrogen peroxide, peracetic acid, perbenzoic acid, and tert-butyl hydroperoxide; permanganate compounds such as potassium permanganate; and dichromic acids such as potassium dichromate. Compounds, halogen acid compounds such as potassium iodate, nitric acid compounds such as nitric acid and iron nitrate, perhalic acid compounds such as perchloric acid, persulfates such as ammonium persulfate, and heteropoly acids. Among these oxidizing agents, hydrogen peroxide and organic peroxides whose decomposition products are harmless, and persulfates such as ammonium persulfate are particularly preferable. One or more of these can be used.
[0031]
Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide. One or more of these can be used.
Examples of the acid include an organic acid and an inorganic acid. Among them, organic acids include paratoluenesulfonic acid, dodecylbenzenesulfonic acid, isoprenesulfonic acid, gluconic acid, lactic acid, citric acid, tartaric acid, malic acid, glycolic acid, malonic acid, formic acid, oxalic acid, succinic acid, fumaric acid , Maleic acid and phthalic acid. In addition, examples of the inorganic acid include nitric acid, hydrochloric acid, and sulfuric acid. One or more of these acids can be used.
[0032]
Examples of the surfactant include a cationic surfactant and an anionic surfactant. Among them, examples of the anionic surfactant include fatty acid soap, carboxylate such as alkyl ether carboxylate, sulfonate such as alkylbenzene sulfonate, alkylnaphthalene sulfonate, α-olefin sulfonate, and higher alcohol sulfate. Examples thereof include sulfates such as ester salts, alkyl ether sulfates, and polyoxyethylene alkylphenyl ether sulfates, and phosphate esters such as alkyl phosphate esters. One or more of these can be used.
[0033]
Examples of the scratch inhibitor include biphenol, bipyridyl, 2-vinylpyridine and 4-vinylpyridine, salicylaldoxime, o-phenylenediamine and m-phenylenediamine, catechol, o-aminophenol, thiourea, and N-alkyl group-containing. (Meth) acrylamide, N-aminoalkyl group-containing (meth) acrylamide, 7-hydroxy-5-methyl-1,3,4-triazaindolizine, 5-methyl-1H-benzotriazole, phthalazine, melamine and 3- Amino-5,6-dimethyl-1,2,4-triazine and the like. One or more of these can be used.
[0034]
In addition, the water-insoluble matrix includes, in addition to the compatibilizer and the various materials conventionally included in the slurry, a filler, a softener, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a plasticizer, and the like. Can be contained. Among them, fillers such as calcium carbonate, magnesium carbonate, talc, clay and other materials for improving rigidity, and silica, alumina, ceria, zirconia, titanium oxide, zirconium oxide, manganese dioxide, manganese trioxide, barium carbonate, etc. A material having a polishing effect or the like may be used.
[0035]
The shape of the polishing pad of the present invention is not particularly limited, but may be, for example, a disk shape, a belt shape, a roller shape, or the like, and is preferably appropriately selected according to a polishing apparatus. Also, the size of the polishing pad before use is not particularly limited. For a disk-shaped polishing pad, for example, the diameter is 0.5 to 500 cm (further 1.0 to 250 cm, particularly 20 to 200 cm) and the thickness is 0.1 mm. It can be more than 100 mm or less (especially 1 to 10 mm).
[0036]
The method for manufacturing the polishing pad of the present invention is not particularly limited, and the method for forming the groove of the polishing pad is not particularly limited. For example, a composition for a polishing pad to be a polishing pad is obtained in advance, the composition is formed into a desired general shape, and then a groove can be formed by cutting. Further, by forming the composition for a polishing pad by use of a mold having a pattern in which a groove is formed, the groove can be formed simultaneously with the general shape of the polishing pad. Further, the surface roughness of the inner surface of the groove can be easily reduced to 20 μm or less according to the die molding. In addition, when the polishing pad is one in which cavities are dispersed in a water-insoluble matrix such as a foam, it is usually used because a skin layer is formed on the surface of the water-insoluble matrix and pores are not formed. Can not.
[0037]
The method for obtaining the polishing pad composition is not particularly limited. For example, the polishing pad composition can be obtained by kneading necessary materials such as a predetermined organic material using a kneader or the like. A conventionally known kneader can be used. For example, kneading machines such as rolls, kneaders, Banbury mixers, and extruders (single-screw, multi-screw) can be used. Further, a polishing pad composition containing water-soluble particles for obtaining a polishing pad containing water-soluble particles can be obtained by, for example, kneading a water-insoluble matrix, water-soluble particles, and other additives. it can. However, usually, at the time of kneading, the mixture is heated and kneaded so as to be easily processed. At this temperature, the water-soluble particles are preferably solid. By being solid, water-soluble particles can be dispersed at the above-mentioned preferred average particle size regardless of the degree of compatibility with the water-insoluble matrix.
Therefore, it is preferable to select the type of water-soluble particles according to the processing temperature of the water-insoluble matrix used.
[0038]
The multilayer polishing pad of the present invention comprises: (1) a polishing layer having a plurality of annular grooves having an opening on the polishing surface side and an inner surface having a surface roughness of 20 μm or less, and a rear surface side of the polishing layer. A polishing layer having a support layer, or (2) a polishing layer having a plurality of annular through holes opened on the polishing surface side and having an inner surface roughness of 20 μm or less, and disposed on the back side of the polishing layer. And a support layer.
[0039]
Among these, the polishing pad of the present invention can be applied as the polishing layer in the former multilayer polishing pad.
The support layer is a layer that supports the polishing layer or the like on the back surface side of the polishing layer. The characteristics of the support layer are not particularly limited, but are preferably softer than the polishing layer. By providing a softer support layer, even when the thickness of the polishing layer is small (for example, 5 mm or less), it is possible to prevent the polishing layer from floating during polishing, or prevent the surface of the polishing layer from being curved. Polishing can be performed stably. The hardness of the support layer is preferably 90% or less (more preferably 80% or less, particularly 70% or less, usually 10% or more) of the hardness of the polishing layer. Further, the Shore D hardness is preferably 70 or less (more preferably 60 or less, further preferably 50 or less).
[0040]
Further, the support layer may be a porous body (foam) or a non-porous body. Further, the planar shape is not particularly limited, and may be the same as or different from the polishing layer. The planar shape of the support layer can be, for example, a circle, a polygon (a square or the like), or the like. The thickness is not particularly limited, but may be, for example, 0.1 to 5 mm (more preferably, 0.5 to 2 mm).
The material constituting the support layer is not particularly limited, but it is preferable to use an organic material because it can be easily formed into a predetermined shape and property and can impart appropriate elasticity and the like. As the organic material, an organic material constituting a water-insoluble matrix in the polishing pad can be used. However, the organic material constituting the support layer may be a crosslinked polymer or a non-crosslinked polymer.
[0041]
On the other hand, the polishing layer in the latter multi-layer type polishing pad is one in which the annular groove in the polishing pad of the present invention has an annular through hole penetrating from the polishing surface side to the back surface side. The shape and size of the groove in the polishing pad can be applied to the planar shape, arrangement, cross-sectional shape, size (width, minimum distance and pitch between adjacent through holes) of the annular through hole, and the like. The depth of the size of the annular through hole is the same as the thickness of the polishing layer (for example, the thickness of the polishing pad can be applied). Further, the polishing layer is bonded or bonded to another layer such as a support layer on the back surface side, so that the polishing layer separated by the annular through hole maintains a predetermined shape. Further, the slurry does not flow out through the through-holes without being subjected to polishing.
In addition, the above-described support layer can be used as the support layer.
[0042]
In these multilayer polishing pads of the present invention, the support layer may include only one layer, or may include two or more layers. Further, the support layer and the polishing layer may be laminated in direct contact with each other, or may be laminated via another layer. Further, the support layer may be bonded to the polishing layer or another layer with an adhesive, an adhesive (adhesive tape or the like), or may be integrally joined by being partially melted.
[0043]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
[1] Manufacturing of polishing pad
Example 1
80 parts by volume of 1,2-polybutadiene (trade name “JSR RB830” manufactured by JSR Corporation) to be crosslinked to form a water-insoluble matrix, and β-cyclodextrin as a water-soluble particle (Yokohama International Bio-Institute, Ltd.) And 20 parts by volume (trade name: Dexy Pearl β-100, average particle size: 20 μm) were kneaded with a ruder adjusted to 160 ° C. to obtain white pellets. Thereafter, 0.3 parts by volume of an organic peroxide (trade name “Park Mill D-40” manufactured by NOF CORPORATION) is compounded, and further kneaded at 120 ° C. Then, the kneaded material is extruded into a mold. The mixture was heated at 170 ° C. for 18 minutes and crosslinked to obtain a disk-shaped molded body having a diameter of 60 cm and a thickness of 2.5 mm. Then, using a cutting machine (manufactured by Kato Machinery Co., Ltd.) on one side of this molded body, the width is 0.5 mm, the depth is 1 mm, and the pitch is 1.5 mm (the distance between adjacent grooves is 1 mm). ) Was formed (see FIG. 1).
[0044]
Next, the surface roughness of the inner surface of the groove was measured in three different visual fields using a three-dimensional surface structure analysis microscope (manufactured by Canon Inc., model “Zygo New View 5032”). As a result, the actual measured values of the surface roughness in all visual fields were within the range of 1.1 to 4.8 μm, the maximum roughness was 4.5 μm on the side surface and 4.8 μm on the bottom surface, and the surface roughness was It was 1.8 μm.
Further, FIG. 4 shows an explanatory diagram of a photograph taken by enlarging a cross section of the polishing pad with an optical microscope and photographing it.
[0045]
Example 2
100 parts by volume of 1,2-polybutadiene (manufactured by JSR Corporation, trade name "JSR RB840") which is crosslinked to form a water-insoluble matrix, and β-cyclodextrin (trade name, manufactured by Yokohama International Bio Research Institute Co., Ltd.) 100 parts by volume of water-soluble particles (average particle size: 20 μm) obtained by coating Dexie Pearl β-100 ”) with a polypeptide were kneaded by a ruder adjusted to 160 ° C. to obtain white pellets. Thereafter, 0.3 parts by volume of an organic peroxide (trade name “Perhexin 25B” manufactured by NOF CORPORATION) was added to the white pellets, and the mixture was further kneaded at 120 ° C. to obtain white pellets. Next, the white pellet to which the organic peroxide was added was placed in a mold, heated at 190 ° C. for 10 minutes, and crosslinked to obtain a disk-shaped molded body having a diameter of 60 cm and a thickness of 2.5 mm. Then, using the same cutting machine as in Example 1 on one surface side of the molded body, the width was 0.5 mm, the depth was 0.5 mm, and the pitch was 1.2 mm (the distance between adjacent grooves was 0.1 mm). 7 mm).
Next, the surface roughness of the inner surface of the groove was measured in the same manner as in Example 1. As a result, the actual measured values of the surface roughness in all the visual fields were within the range of 1.0 to 4.2 μm, the maximum roughness was 3.9 μm on the side surface and 4.2 μm on the bottom surface, and the surface roughness was It was 1.5 μm.
[0046]
Comparative Example 1
Surface of the inner surface of the groove of a polishing pad made of foamed polyurethane (made by Rodel Nitta Co., Ltd., trade name: “IC1000”) having an annular groove having a width of 0.25 mm, a depth of 0.4 mm, and a pitch of 1.5 mm. The roughness was measured as in Example 1. As a result, the measured values of the surface roughness in all visual fields varied widely in the range of 25 to 200 μm, and the surface roughness was 150 μm.
Further, FIG. 5 is an explanatory diagram of a photograph taken by enlarging a cross section of the polishing pad by an optical microscope and photographing the cross section.
[0047]
[2] Evaluation of polishing performance, etc.
The polishing pads of Examples 1 and 2 and Comparative Example 1 were respectively mounted on a surface plate of a polishing apparatus (manufactured by SFT, model "Lapmaster LM-15"), and the rotation speed of the surface plate was reduced to 50 rpm and tripled. A slurry for chemical mechanical polishing (trade name “CMS 1101” manufactured by JSR Co., Ltd.) was treated with SiO ₂ The film wafer was polished for 2 minutes, and when each polishing pad was used, the polishing rate, the presence or absence of scratches, the presence or absence of foreign matter, and the state of pores were evaluated. Each measuring method is as follows.
[0048]
(1) Polishing rate: The film thickness before and after polishing was measured by an optical film thickness meter, and calculated from these film thicknesses.
(2) Presence or absence of scratches and foreign substances: The polished surface of the polished silica film wafer was observed and observed with an electron microscope.
The evaluation criteria for the presence or absence of scratches are as follows: ；: no scratch is observed, ×: scratch is observed. The evaluation criteria for the presence or absence of foreign matter are as follows: ○: no foreign matter is recognized, x: foreign matter is recognized.
(3) Pore condition: The surface of the polishing pad was ground with a # 400 diamond grindstone for 5 minutes and dressed, and the pore condition of the dressed surface was observed with an electron microscope.
The evaluation criteria are: ○: substantially all pores are open, ×: some pores are closed.
As described above, the results of (1) to (3) are also shown in Table 1.
[0049]
[Table 1]

[0050]
From the measurement results of the surface roughness, it can be seen that, in the polishing pad of Comparative Example 1, the inner surface of the groove had severe irregularities and was uneven. Further, according to FIG. 5, a large convex portion is recognized. Further, FIG. 3.63 shown on page 114 of “Detailed Explanation Semiconductor CMP Technology” (edited by Toshiro Doi, published by the Industrial Research Institute, First Edition) shows the same foam as the polishing pad used in Comparative Example 1. It is a photograph by a scanning electron microscope of a polishing pad made of polyurethane (trade name “IC1000” manufactured by Rodale Nitta Co., Ltd.). From this photograph, it can be seen that larger irregularities exist in the groove than in FIG. 4 according to Example 1.
[0051]
Further, from the results shown in Table 1, scratches and foreign substances were observed on the surface to be polished by the polishing pad. Also, the state of the pores after dressing was partially closed and not open. In particular, the pores around the opening of the groove which was easily closed by the dressing were almost completely closed. Further, it can be seen that the polishing rate for Example 1 is 1/4, and the polishing rate for Example 2 is 1/5, which is significantly inferior. This is presumably because pores were blocked by foreign matter during polishing.
[0052]
On the other hand, the polishing pads of Examples 1 and 2 have extremely small surface roughness on both the side surfaces and the bottom surface inside the groove, and are smooth. This can be confirmed from FIG. Therefore, almost no scratch was observed on the surface to be polished, and almost no foreign matter was observed. Further, even after the dressing, the pores were almost completely opened, and in particular, all the pores around the opening of the groove were also opened. The polishing rate of Example 1 was 4 times and that of Example 2 was 5 times faster than Comparative Example 1. This is considered to be because the pore was not blocked by the foreign matter.
[0053]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the polishing pad of this invention, the scratch by the foreign material etc. which generate | occur | produce inside a groove | channel can be suppressed effectively.
In addition, when the groove has a specific depth, width, and interval, the occurrence of scratches is more reliably suppressed.
Furthermore, when having a water-insoluble matrix containing a crosslinked polymer and water-soluble particles, the surface roughness of the inner surface of the groove can be easily suppressed to 20 μm or less, and the pores are not closed even by dressing, The slurry is sufficiently held, and the polishing rate can be increased.
When the groove is formed by cutting and / or molding, the surface roughness of the inner surface of the groove can be easily reduced, and the occurrence of scratches can be suppressed more sufficiently.
According to the multilayer polishing pad of the present invention, scratches due to foreign matter and the like generated inside the groove can be effectively suppressed, and the polished surface of the pad and the surface to be polished such as a wafer can be sufficiently adhered to each other. The polishing rate can be improved.
Further, when the groove or the through hole has a specific depth, width, and interval, generation of scratches can be more reliably suppressed.
Further, when the polishing layer has a water-insoluble matrix containing a crosslinked polymer and water-soluble particles, the surface roughness of the inner surface of the grooves or through holes of the polishing layer can be easily suppressed to 20 μm or less, The pores are not closed by the dressing, the slurry is sufficiently held, and the polishing rate can be increased.
Furthermore, when the groove or the through hole is formed by cutting and / or molding, the surface roughness of the inner surface of the groove can be easily reduced, and the occurrence of scratches can be suppressed more sufficiently.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of an example of a polishing pad and a multilayer polishing pad of the present invention.
FIG. 2 is a schematic plan view of an example of the polishing pad and the multilayer polishing pad of the present invention.
FIG. 3 is a schematic view of a partial cross section including a groove of the polishing pad and the multilayer polishing pad of the present invention.
FIG. 4 is an explanatory view of a partial cross section of the polishing pad of Example 1 by a micrograph.
FIG. 5 is an explanatory diagram by a micrograph of a partial cross section of the polishing pad of Comparative Example 1.
[Explanation of symbols]
1; polishing pad or multilayer polishing pad; 12; annular groove or annular through-hole; 21; pitch; 22; width of groove or through-hole; 23; distance between adjacent grooves.

Claims (10)

A polishing pad having a plurality of annular grooves on the polishing surface side, wherein the inner surface of the grooves has a surface roughness of 20 μm or less and is used for chemical mechanical polishing. The polishing pad according to claim 1, wherein the grooves are arranged concentrically. The polishing pad according to claim 1, wherein the groove has a depth of at least 0.1 mm, a width of at least 0.1 mm, and a minimum distance between adjacent grooves of at least 0.05 mm. The polishing pad according to any one of claims 1 to 3, comprising a water-insoluble matrix containing a cross-linked polymer, and water-soluble particles dispersed in the water-insoluble matrix. The polishing pad according to claim 1, wherein the groove is formed by cutting and / or molding. A polishing layer having a plurality of annular grooves or a plurality of annular through-holes that are opened on the polishing surface side and whose inner surface has a surface roughness of 20 μm or less, and a support layer disposed on the back side of the polishing layer. A multilayer polishing pad, comprising: a polishing pad for use in chemical mechanical polishing. The multi-layer polishing pad according to claim 6, wherein the grooves or the through holes are arranged concentrically. The groove or the through hole has a depth of 0.1 mm or more, a width of 0.1 mm or more, and a minimum distance between adjacent grooves or the through holes is 0.05 mm or more. 8. The multilayer polishing pad according to 7. The multilayer type according to any one of claims 6 to 8, wherein the polishing layer has a water-insoluble matrix containing a crosslinked polymer and water-soluble particles dispersed in the water-insoluble matrix. Polishing pad. The multilayer polishing pad according to any one of claims 6 to 9, wherein the groove or the through hole is formed by cutting and / or molding.

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