JP5355310B2 - Holding pad - Google Patents
Holding pad Download PDFInfo
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- JP5355310B2 JP5355310B2 JP2009204003A JP2009204003A JP5355310B2 JP 5355310 B2 JP5355310 B2 JP 5355310B2 JP 2009204003 A JP2009204003 A JP 2009204003A JP 2009204003 A JP2009204003 A JP 2009204003A JP 5355310 B2 JP5355310 B2 JP 5355310B2
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- holding
- foam
- thickness direction
- holding pad
- foaming
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- 239000006260 foam Substances 0.000 claims description 89
- 238000005187 foaming Methods 0.000 claims description 38
- 230000015271 coagulation Effects 0.000 claims description 35
- 238000005345 coagulation Methods 0.000 claims description 35
- 238000000034 method Methods 0.000 claims description 24
- 229920005989 resin Polymers 0.000 claims description 24
- 239000011347 resin Substances 0.000 claims description 24
- 230000015572 biosynthetic process Effects 0.000 claims description 21
- 229920005749 polyurethane resin Polymers 0.000 description 62
- 239000010410 layer Substances 0.000 description 54
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 53
- 238000005498 polishing Methods 0.000 description 37
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 35
- 239000000758 substrate Substances 0.000 description 24
- 239000007788 liquid Substances 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 15
- 239000000463 material Substances 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 13
- 238000005259 measurement Methods 0.000 description 11
- 230000001112 coagulating effect Effects 0.000 description 9
- 230000008929 regeneration Effects 0.000 description 8
- 238000011069 regeneration method Methods 0.000 description 8
- 238000007517 polishing process Methods 0.000 description 6
- 239000000654 additive Substances 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 239000011521 glass Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 229920002799 BoPET Polymers 0.000 description 4
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 4
- 230000000996 additive effect Effects 0.000 description 4
- 229920000728 polyester Polymers 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000003960 organic solvent Substances 0.000 description 3
- 229920000139 polyethylene terephthalate Polymers 0.000 description 3
- 239000005020 polyethylene terephthalate Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 2
- 239000012790 adhesive layer Substances 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
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- 238000011156 evaluation Methods 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- -1 polyethylene terephthalate Polymers 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 241000501754 Astronotus ocellatus Species 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000006061 abrasive grain Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000002438 flame photometric detection Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 238000010191 image analysis Methods 0.000 description 1
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- 230000001771 impaired effect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 150000003673 urethanes Chemical class 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
- B24B37/11—Lapping tools
- B24B37/20—Lapping pads for working plane surfaces
- B24B37/22—Lapping pads for working plane surfaces characterised by a multi-layered structure
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Description
本発明は保持パッドに係り、特に、湿式凝固法により厚み全体にわたる大きさの多数の縦型発泡が形成され被研磨物を保持するための保持面を有する樹脂シートを備えた保持パッドに関する。 The present invention relates to a holding pad, and more particularly to a holding pad provided with a resin sheet having a holding surface for holding an object to be polished in which a number of vertical foams having a size over the entire thickness are formed by a wet coagulation method.
半導体用ウエハ（ＷＦ）、フラットパネルディスプレイ（ＦＰＤ）用ガラス基板やハードディスク用基板等の各種材料（被研磨物）の表面（加工面）では、平坦性を向上させるために、対向配置された２つの定盤を備えた研磨機を用いた研磨加工が行われている。これら被研磨物の中でも、半導体用ＷＦやＦＰＤ用ガラス基板では、欠陥のない積層配線の高集積化や高画質画像を演出するため、それらの基礎となる基板の平坦性に対する要求度がますます高まっている。 On the surface (processed surface) of various materials (objects to be polished) such as a semiconductor wafer (WF), a glass substrate for a flat panel display (FPD), and a substrate for a hard disk, the two are arranged to face each other. Polishing using a polishing machine having two surface plates is performed. Among these objects to be polished, WF for semiconductors and glass substrates for FPDs have a higher degree of demand for flatness of their underlying substrates in order to produce highly integrated multilayer wiring without defects and produce high-quality images. It is growing.
被研磨物を、例えば、片面を研磨加工するときは、研磨機の一方の定盤に研磨パッドが装着され、他方の定盤に被研磨物が研磨パッドと対向するように保持される。研磨加工時には、被研磨物と研磨パッドとの間に研磨粒子（砥粒）を含む研磨スラリが供給され、被研磨物に研磨圧（押圧力）がかけられる。被研磨物が定盤との接触で損傷を受けることを回避するために、通常、被研磨物を保持する定盤には保持パッドが装着されている。すなわち、保持パッドでは、研磨プロセスにおいて被研磨物を一時的に保持することができる。また、保持パッドには、被研磨物の横ずれを抑制するために型枠が使用されることがある。型枠の使用の有無は被研磨物の種類で異なり、例えば、ＦＰＤ用ガラス基板の研磨加工では型枠の無い保持パッドが使用される。 For example, when polishing an object to be polished on one side, a polishing pad is mounted on one surface plate of the polishing machine, and the object to be polished is held on the other surface plate so as to face the polishing pad. At the time of polishing, a polishing slurry containing abrasive particles (abrasive grains) is supplied between the object to be polished and the polishing pad, and a polishing pressure (pressing force) is applied to the object to be polished. In order to prevent the object to be polished from being damaged by contact with the surface plate, a holding pad is usually attached to the surface plate that holds the object to be polished. That is, the holding pad can temporarily hold an object to be polished in the polishing process. In addition, a mold may be used for the holding pad in order to suppress lateral displacement of the object to be polished. Whether or not the mold is used differs depending on the type of the object to be polished. For example, a holding pad without a mold is used for polishing a glass substrate for FPD.
保持パッドとしては、湿式凝固法により形成された発泡構造を有する軟質のウレタンフィルム（樹脂シート）を備えた保持パッドが使用されている（例えば、特許文献１参照）。湿式凝固法により形成されるウレタンフィルムでは、厚みのほぼ全体にわたる大きさの発泡が形成されるため、クッション性を高める目的で発泡サイズを大きくすると、被研磨物を保持するための保持面近傍まで発泡サイズが大きくなり、剛性が低下してしまう。クッション性が低すぎると研磨圧により被研磨物が受ける応力にムラが生じるため、被研磨物の保持パッド側への沈み込みの大きい凸部に応力が集中し、この応力集中部分が過剰研磨されて研磨ムラが生じる。反対に、クッション性が高くなると被研磨物が受ける応力にムラが生じ難くなり、被研磨物の表面平滑性が向上するものの、沈み込みが大きくなり保持パッド自体が削られる可能性がある。被研磨物の沈みこみ抑制に必要な剛性と、被研磨物に対する応力の均等化に必要なクッション性とを両立させる技術として、湿式凝固法による発泡構造の異なる２種のシートを貼り合わせた保持パッドの技術が開示されている（例えば、特許文献２参照）。この技術では、一方のシートでクッション性を確保しつつ、他方のシートで剛性が発揮される。 As the holding pad, a holding pad provided with a soft urethane film (resin sheet) having a foam structure formed by a wet coagulation method is used (for example, see Patent Document 1). In the urethane film formed by the wet coagulation method, foam of almost the entire thickness is formed, so if the foam size is increased for the purpose of improving cushioning properties, it will reach the vicinity of the holding surface for holding the workpiece The foam size increases and the rigidity decreases. If the cushioning property is too low, the stress applied to the workpiece will be uneven due to the polishing pressure, so stress concentrates on the convex portion where the sinking of the workpiece to the holding pad side is large, and this stress concentration portion is excessively polished. Cause uneven polishing. On the other hand, when the cushioning property is high, unevenness is hardly generated in the stress received by the object to be polished, and the surface smoothness of the object to be polished is improved, but the sinking becomes large and the holding pad itself may be scraped off. Holding two types of sheets with different foamed structures by wet coagulation as a technology to achieve both the rigidity required to suppress sinking of the workpiece and the cushioning required to equalize the stress on the workpiece A pad technology is disclosed (see, for example, Patent Document 2). In this technique, rigidity is exhibited in the other sheet while securing cushioning property in one sheet.
しかしながら、特許文献１の技術では、湿式凝固法により形成された表面層（スキン層）の表面（保持面）が平滑性を有することから、被研磨物を略平坦に保持することができるものの、上述した高度な平坦性の要求を満たすには十分とはいえない。特許文献２の技術では、２種のシートの貼り合わせに用いる接着剤等の影響により、硬さが不均一となることがある。また、研磨加工時に２種のシートが剥離してしまう、という問題もある。研磨加工時には、通常、被研磨物が保持パッドに沈み込み保持されながら平坦化されることから、クッション性を有する保持パッドが圧縮されることで被研磨物に対して応力が発生する。このとき、保持パッドの密度にバラツキがあると、バラツキ部分ごとにかかる応力の大きさが異なり局所的に押圧力が変わるため、加工面を全域にわたって均一に研磨加工することが難しくなり、面内均一性が損なわれる。例えば、被研磨物の外縁部と中央部とで研磨取り代が異なり、いわゆる外縁だれが生じることとなる。被研磨物に与える応力のムラを低減して保持面の平坦性精度を高めることができれば、被研磨物に対する高度な平坦性の要求を満たすレベルの保持パッドを得ることが可能となる。 However, in the technique of Patent Document 1, since the surface (holding surface) of the surface layer (skin layer) formed by the wet coagulation method has smoothness, the object to be polished can be held substantially flat, It cannot be said that it is sufficient to satisfy the above-described demand for high flatness. In the technique of Patent Document 2, the hardness may be uneven due to the influence of an adhesive or the like used for bonding two types of sheets. There is also a problem that the two types of sheets are peeled off during polishing. At the time of polishing, the object to be polished is usually flattened while being submerged and held in the holding pad. Therefore, stress is generated on the object to be polished by compressing the holding pad having cushioning properties. At this time, if there is variation in the density of the holding pad, the stress applied to each variation will vary and the pressing force will vary locally, making it difficult to polish the processing surface uniformly over the entire area. Uniformity is impaired. For example, the polishing allowance differs between the outer edge portion and the center portion of the object to be polished, and so-called outer edge dripping occurs. If the unevenness of stress applied to the object to be polished can be reduced and the flatness accuracy of the holding surface can be increased, it is possible to obtain a holding pad at a level that satisfies the high level of flatness requirements for the object to be polished.
本発明は上記事案に鑑み、保持面の平坦性精度を高め被研磨物の面内均一性を向上させることができる保持パッドを提供することを課題とする。 An object of the present invention is to provide a holding pad that can improve the flatness accuracy of the holding surface and improve the in-plane uniformity of the object to be polished.
上記課題を解決するために、本発明は、湿式凝固法により厚み全体にわたる大きさの多数の縦型発泡が形成され被研磨物を保持するための保持面を有する樹脂シートを備えた保持パッドにおいて、前記発泡は、前記樹脂シートの厚み方向中央部から前記保持面側の発泡端部までの発泡形成方向が前記厚み方向に対して一定方向に一様に傾斜するように形成されていることを特徴とする。 In order to solve the above-described problems, the present invention provides a holding pad including a resin sheet having a holding surface for holding an object to be polished, in which a number of vertical foams having a size over the entire thickness are formed by a wet coagulation method. The foaming is formed such that the foaming direction from the central part in the thickness direction of the resin sheet to the foaming end part on the holding surface side is uniformly inclined in a certain direction with respect to the thickness direction. Features.
本発明では、発泡が樹脂シートの厚み方向中央部から保持面側の発泡端部までの発泡形成方向が厚み方向に対して一定方向に一様に傾斜するように形成されているため、湿式凝固時に樹脂シートに密度ムラが生じても、研磨加工時に圧縮されたときに被研磨物に対する応力が全面積にわたり均等化されることから、保持面の平坦性精度を高め被研磨物の面内均一性を向上させることができる。 In the present invention, the foaming is formed so that the foaming direction from the central part in the thickness direction of the resin sheet to the foaming end part on the holding surface side is uniformly inclined in a constant direction with respect to the thickness direction. Even if density unevenness occurs in the resin sheet sometimes, the stress on the workpiece is equalized over the entire area when compressed during polishing, so the flatness accuracy of the holding surface is increased and the surface of the workpiece is evenly distributed. Can be improved.
この場合において、樹脂シートの厚み方向中央部を全体の厚みに対して厚み方向の中心から±１０％の範囲とすることができる。発泡が厚み方向中央部から保持面の背面側の発泡端部までが保持面側の発泡端部までより径が大きいことが好ましい。また、発泡が厚み方向中央部から保持面の背面側の発泡端部までの発泡形成方向が厚み方向に沿うように形成されていてもよい。このような発泡では、保持面近傍で保持面と平行な断面に形成された孔の中心をとおる垂直線が保持面の背面近傍で該背面と平行な断面と交わる位置が背面と平行な断面に同じ発泡で形成された孔の外側に位置するようにすることができる。発泡が、厚み方向中央で保持面と平行な断面に形成された孔の中心Ｍ１と保持面側の頂点Ｍ２とを結ぶ線分を斜辺とする直角三角形における中心Ｍ１から頂点Ｍ２を見た場合の仰角をθとしたときに、仰角θが３０度〜６０度の範囲となるように形成されていてもよい。樹脂シートが湿式凝固法により長尺状に形成されたものであり、発泡が厚み方向中央部から保持面側の発泡端部までの発泡形成方向が厚み方向に対して樹脂シートの長手方向に傾斜するように形成されていてもよい。また、発泡が長手方向と交差する幅方向で厚み方向に沿うように形成されていてもよい。このとき、発泡を長手方向と交差する幅方向の断面から見たときに垂直方向に形成することができる。 In this case, the central portion in the thickness direction of the resin sheet can be within a range of ± 10% from the center in the thickness direction with respect to the entire thickness. It is preferable that the foaming has a larger diameter from the center in the thickness direction to the foaming end on the back side of the holding surface than the foaming end on the holding surface. Further, the foam may be formed such that the foam formation direction from the central portion in the thickness direction to the foam end portion on the back side of the holding surface is along the thickness direction. In such foaming, the vertical line passing through the center of the hole formed in the cross section parallel to the holding surface in the vicinity of the holding surface crosses the cross section parallel to the back surface in the vicinity of the back surface of the holding surface. It can be located outside the holes formed of the same foam. When the vertex M2 is viewed from the center M1 in the right triangle whose hypotenuse is the line connecting the center M1 of the hole formed in a cross section parallel to the holding surface at the center in the thickness direction and the vertex M2 on the holding surface side. When the elevation angle is θ, the elevation angle θ may be formed in a range of 30 degrees to 60 degrees. The resin sheet is formed in a long shape by a wet coagulation method, and the foam formation direction from the central part in the thickness direction to the foam end on the holding surface side is inclined in the longitudinal direction of the resin sheet with respect to the thickness direction. It may be formed so as to. Moreover, you may form so that foaming may follow a thickness direction in the width direction which cross | intersects a longitudinal direction. At this time, the foam can be formed in the vertical direction when viewed from a cross section in the width direction intersecting the longitudinal direction.
本発明によれば、発泡が樹脂シートの厚み方向中央部から保持面側の発泡端部までの発泡形成方向が厚み方向に対して一定方向に一様に傾斜するように形成されているため、湿式凝固時に樹脂シートに密度ムラが生じても、研磨加工時に圧縮されたときに被研磨物に対する応力が全面積にわたり均等化されることから、保持面の平坦性精度を高め被研磨物の面内均一性を向上させることができる、という効果を得ることができる。 According to the present invention, the foam is formed such that the foam formation direction from the central portion in the thickness direction of the resin sheet to the foam end on the holding surface side is uniformly inclined in a constant direction with respect to the thickness direction. Even if density unevenness occurs in the resin sheet during wet coagulation, the stress on the object to be polished is equalized over the entire area when compressed during the polishing process. The effect that internal uniformity can be improved can be acquired.
以下、図面を参照して、本発明を適用した保持パッドの実施の形態について説明する。 Hereinafter, embodiments of a holding pad to which the present invention is applied will be described with reference to the drawings.
（構成）
図１に示すように、本実施形態の保持パッド１０は、ポリウレタン樹脂製の樹脂シートとしてのウレタンシート２を備えている。ウレタンシート２は、湿式凝固法により形成されており、被研磨物を保持するための保持面Ｓｈを有している。
(Constitution)
As shown in FIG. 1, the holding pad 10 of the present embodiment includes a urethane sheet 2 as a resin sheet made of polyurethane resin. The urethane sheet 2 is formed by a wet coagulation method and has a holding surface Sh for holding an object to be polished.
ウレタンシート２は、保持面Ｓｈの直近で数μｍ程度の厚みにわたり緻密な微多孔が形成されたスキン層２ａを有している。すなわち、スキン層２ａは微多孔構造を有している。ウレタンシート２のスキン層２ａより内側（内部）には、多数の発泡４が略均等に分散した状態で形成されている。発泡４は、ウレタンシート２の厚みのほぼ全体にわたる大きさを有しており、厚み方向に縦長状で丸みを帯びた円錐状に形成されている。ウレタンシート２がスキン層２ａを有するため、保持面Ｓｈには、発泡４の開口は形成されていない。発泡４同士の間のポリウレタン樹脂中には、発泡４より小さい小発泡が形成されている。ウレタンシート２では、スキン層２ａの微多孔、発泡４および小発泡が網目状に連通しており、発泡が連続発泡状に形成された連続発泡構造を有している。 The urethane sheet 2 has a skin layer 2a in which dense micropores are formed over a thickness of about several μm in the immediate vicinity of the holding surface Sh. That is, the skin layer 2a has a microporous structure. Inside the skin layer 2 a of the urethane sheet 2, a large number of foams 4 are formed in a substantially uniformly dispersed state. The foam 4 has a size over almost the entire thickness of the urethane sheet 2 and is formed in a conical shape that is vertically long and round in the thickness direction. Since the urethane sheet 2 has the skin layer 2a, the opening of the foam 4 is not formed on the holding surface Sh. Small foam smaller than the foam 4 is formed in the polyurethane resin between the foams 4. The urethane sheet 2 has a continuous foaming structure in which the fine porosity, foaming 4 and small foaming of the skin layer 2a are communicated in a mesh shape, and foaming is formed in a continuous foaming shape.
発泡４は、ウレタンシート２の厚み方向中央部から保持面Ｓｈ側の上部層Ｐｈと、厚み方向中央部から保持面Ｓｈと反対の面（以下、裏面Ｓｒという。）側の下部層Ｐｒとで形成状態が異なっている。すなわち、発泡４は、下部層Ｐｒでの孔径が上部層Ｐｈでの孔径より大きく形成されている。また、発泡４は、上部層Ｐｈにおける保持面Ｓｈ側の発泡端部までの発泡形成方向が厚み方向に対して一定方向に一様に傾斜するように形成されており、下部層Ｐｒにおける裏面Ｓｒ側の発泡端部までの発泡形成方向が厚み方向に沿うように形成されている。換言すれば、発泡４の発泡形成方向は、上層部Ｐｈでは厚み方向に対して傾斜する方向（図１の矢印Ａ方向）に沿っており、下部層Ｐｒでは厚み方向（矢印Ｂ方向）に沿っている。 The foam 4 includes an upper layer Ph on the holding surface Sh side from the central portion in the thickness direction of the urethane sheet 2 and a lower layer Pr on the surface opposite to the holding surface Sh (hereinafter referred to as the back surface Sr) from the central portion in the thickness direction. The formation state is different. That is, the foam 4 is formed such that the hole diameter in the lower layer Pr is larger than the hole diameter in the upper layer Ph. The foam 4 is formed such that the foam formation direction to the foam end on the holding surface Sh side in the upper layer Ph is uniformly inclined in a constant direction with respect to the thickness direction, and the back surface Sr in the lower layer Pr. The foam formation direction to the foaming end on the side is formed so as to be along the thickness direction. In other words, the foam formation direction of the foam 4 is along the direction inclined with respect to the thickness direction (the direction of arrow A in FIG. 1) in the upper layer portion Ph, and along the thickness direction (the direction of arrow B) in the lower layer Pr. ing.
上部層Ｐｈで発泡４が傾斜するように形成されているため、保持面Ｓｈ近傍で保持面Ｓｈと平行な断面に発泡４により形成された孔の中心をとおる垂直線が裏面Ｓｒ近傍で裏面Ｓｒと平行な断面と交わる位置が裏面Ｓｒと平行な断面に同じ発泡４で形成された孔の外側に位置する。すなわち、図２（Ａ）に示すように、保持面Ｓｈの近傍である保持面Ｓｈから５０〜１００μｍ程度内側の位置（矢印ａの位置）、ウレタンシート２の厚み方向中央の位置（矢印ｂの位置）、裏面Ｓｒ近傍である裏面Ｓｒから５０〜１００μｍ程度内側の位置（矢印ｃの位置）とする。この場合、図２（Ｂ）に示すように、保持面Ｓｈ近傍のａ−ａ断面では、発泡４により、中心Ｍａの孔Ｈａが形成される。同様に、ウレタンシート２の厚み方向中央部のｂ−ｂ断面では同じ発泡４により中心Ｍｂの孔Ｈｂが形成され、裏面Ｓｒ近傍のｃ−ｃ断面では同じ発泡４により中心Ｍｃの孔Ｈｃが形成される。孔Ｈａの中心Ｍａ、孔Ｈｂの中心Ｍｂ、孔Ｈｃの中心Ｍｃは、厚み方向に揃うことなく、ズレた位置に位置している。つまり、孔Ｈａの中心Ｍａをとおる垂直線Ｌがｃ−ｃ断面と交点Ｑで交わる。このため、交点Ｑは孔Ｈｃの外側に位置することとなる。また、孔Ｈｃの半径をＲｃとし、孔Ｈｃの中心Ｍｃと交点Ｑとの距離をＬｃとしたときに、距離Ｌｃが半径Ｒｃの２〜５倍の大きさを有している。 Since the foam 4 is inclined in the upper layer Ph, the vertical line passing through the center of the hole formed by the foam 4 in the cross section parallel to the holding surface Sh in the vicinity of the holding surface Sh is near the back surface Sr. The position intersecting the cross section parallel to the back surface Sr is located outside the hole formed by the same foam 4 in the cross section parallel to the back surface Sr. That is, as shown in FIG. 2 (A), a position about 50 to 100 μm from the holding surface Sh that is in the vicinity of the holding surface Sh (position of the arrow a), a center position in the thickness direction of the urethane sheet 2 (of the arrow b) Position), and a position about 50 to 100 μm from the back surface Sr in the vicinity of the back surface Sr (position of arrow c). In this case, as shown in FIG. 2B, a hole Ha at the center Ma is formed by the foaming 4 in the aa cross section in the vicinity of the holding surface Sh. Similarly, a hole Hb of the center Mb is formed by the same foam 4 in the bb cross section at the central portion in the thickness direction of the urethane sheet 2, and a hole Hc of the center Mc is formed by the same foam 4 in the cc cross section near the back surface Sr. Is done. The center Ma of the hole Ha, the center Mb of the hole Hb, and the center Mc of the hole Hc are not aligned in the thickness direction and are located at a shifted position. That is, the vertical line L passing through the center Ma of the hole Ha intersects the cc cross section at the intersection Q. For this reason, the intersection point Q is located outside the hole Hc. Further, when the radius of the hole Hc is Rc, and the distance between the center Mc of the hole Hc and the intersection Q is Lc, the distance Lc is 2 to 5 times the radius Rc.
ここで、ウレタンシート２に形成された発泡４の傾斜の程度について説明する。図３に示すように、ウレタンシート２の厚み方向に沿う断面では、厚み方向中央で保持面Ｓｈと平行な断面（図２（Ｂ）のｂ−ｂ断面参照。）に発泡４により中心Ｍ１の孔が形成されることとなる。この中心Ｍ１をとおり厚み方向（図３の上下方向）と直交する方向（図３の左右方向）の直線と、発泡４の保持面Ｓｈ側の頂点Ｍ２をとおりウレタンシート２の厚み方向の直線との交点をＰとすると、中心Ｍ１と頂点Ｍ２とを結ぶ線分を斜辺とする直角三角形が形成される。この直角三角形では、中心Ｍ１から頂点Ｍ２を見たときに仰角θが形成される。ウレタンシート２の上部層Ｐｈでは、この仰角θが３０〜６０度の範囲となるように発泡４が形成されている。この場合、中心Ｍ１と交点Ｐとを結ぶ線分の長さをｘとし、頂点Ｍ２と交点Ｐとを結ぶ線分の長さをｙとしたときに、ｔａｎθ＝ｙ／ｘが０．５８〜１．７３の範囲となる。ここで、仰角θは、三次元計測Ｘ線ＣＴを使用してウレタンシート２の内部断面写真を非破壊で撮影し、画像解析装置にて中心Ｍ１と頂点Ｍ２とを位置決めすることにより得られた値である。簡易的には、湿式成膜時の長手方向に沿う厚み方向の断面を走査型電子顕微鏡にて撮影し、中心Ｍ１と頂点Ｍ２とを決定することで仰角θを算出することも可能である。 Here, the degree of inclination of the foam 4 formed on the urethane sheet 2 will be described. As shown in FIG. 3, in the cross section along the thickness direction of the urethane sheet 2, the center M <b> 1 is centered by the foam 4 on the cross section parallel to the holding surface Sh at the center in the thickness direction (see the bb cross section in FIG. 2B). A hole will be formed. A straight line in the direction (left and right direction in FIG. 3) perpendicular to the thickness direction (vertical direction in FIG. 3) passing through the center M1, and a straight line in the thickness direction of the urethane sheet 2 through the vertex M2 on the holding surface Sh side of the foam 4 If the intersection of P is P, a right-angled triangle is formed with the line segment connecting the center M1 and the vertex M2 as the hypotenuse. In this right triangle, an elevation angle θ is formed when the vertex M2 is viewed from the center M1. In the upper layer Ph of the urethane sheet 2, the foam 4 is formed so that the elevation angle θ is in the range of 30 to 60 degrees. In this case, when the length of the line segment connecting the center M1 and the intersection point P is x and the length of the line segment connecting the vertex M2 and the intersection point P is y, tan θ = y / x is 0.58˜ The range is 1.73. Here, the elevation angle θ was obtained by taking a non-destructive photograph of an internal cross-section of the urethane sheet 2 using a three-dimensional measurement X-ray CT and positioning the center M1 and the vertex M2 with an image analyzer. Value. In a simple manner, the elevation angle θ can be calculated by taking a cross section in the thickness direction along the longitudinal direction during wet film formation with a scanning electron microscope and determining the center M1 and the vertex M2.
また、保持パッド１０は、ウレタンシート２の裏面Ｓｒ側に、研磨機に保持パッド１０を装着するための両面テープ７が貼り合わされている。両面テープ７は、図示しない基材を有しており、基材の両面にアクリル系粘着剤等の感圧型粘着剤層（不図示）がそれぞれ形成されている。基材には、例えば、ポリエチレンテレフタレート（以下、ＰＥＴと略記する。）製フィルム等の可撓性フィルムが用いられている。両面テープ７は、基材の一面側の粘着剤層でウレタンシート２と貼り合わされており、他面側（ウレタンシート２と反対側）の粘着剤層が表面を剥離紙８で覆われている。なお、この両面テープ７の基材は、保持パッド１０の基材も兼ねている。 Further, the holding pad 10 has a double-sided tape 7 for attaching the holding pad 10 to the polishing machine attached to the back surface Sr side of the urethane sheet 2. The double-sided tape 7 has a base material (not shown), and a pressure-sensitive adhesive layer (not shown) such as an acrylic pressure-sensitive adhesive is formed on both sides of the base material. For the base material, for example, a flexible film such as a film made of polyethylene terephthalate (hereinafter abbreviated as PET) is used. The double-sided tape 7 is bonded to the urethane sheet 2 with an adhesive layer on one side of the base material, and the adhesive layer on the other side (the side opposite to the urethane sheet 2) is covered with the release paper 8 on the surface. . The base material of the double-sided tape 7 also serves as the base material of the holding pad 10.
（製造）
保持パッド１０は、湿式凝固法により形成されたウレタンシート２と両面テープ７とを貼り合わせることで製造される。すなわち、ポリウレタン樹脂溶液を準備する準備工程、成膜基材にポリウレタン樹脂溶液を塗布し、凝固液中でポリウレタン樹脂溶液を凝固させポリウレタン樹脂を再生させる凝固再生工程、シート状のポリウレタン樹脂を洗浄し乾燥させる洗浄・乾燥工程、得られたウレタンシート２と両面テープ７とを貼り合わせるラミネート工程を経て保持パッド１０が製造される。以下、工程順に説明する。
(Manufacturing)
The holding pad 10 is manufactured by bonding the urethane sheet 2 formed by the wet coagulation method and the double-sided tape 7 together. That is, a preparation process for preparing a polyurethane resin solution, a polyurethane resin solution is applied to a film forming substrate, a coagulation regeneration process for coagulating the polyurethane resin solution in a coagulation liquid to regenerate the polyurethane resin, and washing the sheet-like polyurethane resin. The holding pad 10 is manufactured through a cleaning / drying process for drying and a laminating process for bonding the obtained urethane sheet 2 and the double-sided tape 7 together. Hereinafter, it demonstrates in order of a process.
準備工程では、ポリウレタン樹脂、ポリウレタン樹脂を溶解可能な水混和性の有機溶媒および添加剤を混合してポリウレタン樹脂を溶解させる。有機溶媒としては、Ｎ，Ｎ−ジメチルホルムアミド（以下、ＤＭＦと略記する。）やＮ，Ｎ−ジメチルアセトアミド（ＤＭＡｃ）等を挙げることができるが、本例では、ＤＭＦを用いる。ポリウレタン樹脂は、ポリエステル系、ポリエーテル系、ポリカーボネート系等の樹脂から選択して用いることができる。上述した発泡構造を形成することを考慮すれば、ＤＭＦにポリウレタン樹脂を２０重量％で溶解させた樹脂溶液について、Ｂ型回転粘度計を使用し２５℃で測定した粘度が３〜１０Ｐａ・ｓの範囲、好ましくは３〜６Ｐａ・ｓの範囲の樹脂を選定し用いることが望ましい。このポリウレタン樹脂を１０〜３０重量％の範囲、好ましくは１５〜２５重量％の範囲となるようにＤＭＦに溶解させる。ポリウレタン樹脂溶液の粘性は、用いるポリウレタン樹脂の濃度や分子量に加えて、分子構造にも依存するため、これらを総合的に考慮し、ポリウレタン樹脂の選定や濃度設定等を行うことが重要である。また、保持パッド用のポリウレタン樹脂としては、１００％モジュラスが２０ＭＰａ以下のものを用いることが好ましく、１０ＭＰａ以下のものを用いることが更に好ましい。低モジュラスのポリウレタン樹脂を用いることで、被研磨物の密着性が高まり、保持力を向上させることができる。 In the preparation step, the polyurethane resin is dissolved by mixing the polyurethane resin, a water-miscible organic solvent capable of dissolving the polyurethane resin, and an additive. Examples of the organic solvent include N, N-dimethylformamide (hereinafter abbreviated as DMF) and N, N-dimethylacetamide (DMAc). In this example, DMF is used. The polyurethane resin can be selected from resins such as polyester, polyether and polycarbonate. Considering the formation of the foamed structure described above, a resin solution in which a polyurethane resin is dissolved in DMF at 20% by weight has a viscosity of 3 to 10 Pa · s measured at 25 ° C. using a B-type rotational viscometer. It is desirable to select and use a resin having a range, preferably 3 to 6 Pa · s. This polyurethane resin is dissolved in DMF so as to be in the range of 10 to 30% by weight, preferably in the range of 15 to 25% by weight. Since the viscosity of the polyurethane resin solution depends on the molecular structure in addition to the concentration and molecular weight of the polyurethane resin to be used, it is important to select the polyurethane resin and set the concentration in consideration of these comprehensively. Further, as the polyurethane resin for the holding pad, it is preferable to use a resin having a 100% modulus of 20 MPa or less, and more preferably 10 MPa or less. By using a low modulus polyurethane resin, the adhesion of the object to be polished is increased and the holding power can be improved.
また、添加剤としては、発泡４の大きさや量（個数）および上部層Ｐｈにおける傾斜状の発泡形成を制御するため、カーボンブラック等の顔料、親水性添加剤、疎水性添加剤等を用いることができる。これらの添加剤には、通常用いられる各種の材料を用いることができる。得られた溶液を減圧下で脱泡してポリウレタン樹脂溶液を得る。 In addition, as an additive, a pigment such as carbon black, a hydrophilic additive, a hydrophobic additive, or the like is used in order to control the size and amount (number) of foam 4 and the formation of an inclined foam in the upper layer Ph. Can do. For these additives, various commonly used materials can be used. The resulting solution is degassed under reduced pressure to obtain a polyurethane resin solution.
凝固再生工程では、準備工程で得られたポリウレタン樹脂溶液を常温下でナイフコータ等の塗布装置により帯状の成膜基材にシート状に略均一に塗布する。このとき、ナイフコータ等と成膜基材との間隙（クリアランス）を調整することで、ポリウレタン樹脂溶液の塗布厚み（塗布量）を調整する。本例では、塗布厚みが０．８〜１．２ｍｍの範囲となるようにクリアランスを調整する。成膜基材としては、樹脂製フィルム、布帛、不織布等を用いることができるが、本例では、ＰＥＴ製フィルムを用いる。 In the coagulation regeneration step, the polyurethane resin solution obtained in the preparation step is applied substantially uniformly in a sheet form to the belt-shaped film forming substrate at a normal temperature by a coating device such as a knife coater. At this time, the application thickness (application amount) of the polyurethane resin solution is adjusted by adjusting the gap (clearance) between the knife coater and the film forming substrate. In this example, the clearance is adjusted so that the coating thickness is in the range of 0.8 to 1.2 mm. As the film forming substrate, a resin film, a fabric, a nonwoven fabric, or the like can be used. In this example, a PET film is used.
成膜基材に塗布されたポリウレタン樹脂溶液を、ポリウレタン樹脂に対して貧溶媒である水を主成分とする凝固液（水系凝固液）中に連続的に案内する。凝固液には、ポリウレタン樹脂の再生速度を調整するために、ＤＭＦやＤＭＦ以外の極性溶媒等の有機溶媒を添加してもよいが、本例では、水を使用する。また、凝固液の温度を、本例では、１５〜２０℃に設定する。凝固液中では、まず、ポリウレタン樹脂溶液と凝固液との界面に皮膜が形成され、皮膜の直近のポリウレタン樹脂中にスキン層２ａを構成する無数の微多孔が形成される。その後、ポリウレタン樹脂溶液中のＤＭＦの凝固液中への拡散と、ポリウレタン樹脂中への水の浸入との協調現象により連続発泡構造を有するポリウレタン樹脂の再生が進行する。このとき、成膜基材のＰＥＴ製フィルムが凝固液を浸透させないため、ＤＭＦと水との置換がスキン層２ａ側で生じ、成膜基材側がスキン層２ａ側より大きな発泡４が形成される。 The polyurethane resin solution applied to the film forming substrate is continuously guided into a coagulating liquid (water-based coagulating liquid) whose main component is water which is a poor solvent for the polyurethane resin. In order to adjust the regeneration speed of the polyurethane resin, an organic solvent such as DMF or a polar solvent other than DMF may be added to the coagulation liquid. In this example, water is used. Moreover, the temperature of coagulation liquid is set to 15-20 degreeC in this example. In the coagulating liquid, first, a film is formed at the interface between the polyurethane resin solution and the coagulating liquid, and innumerable micropores constituting the skin layer 2a are formed in the polyurethane resin immediately adjacent to the film. Thereafter, regeneration of the polyurethane resin having a continuous foamed structure proceeds by a cooperative phenomenon of diffusion of DMF in the polyurethane resin solution into the coagulating liquid and penetration of water into the polyurethane resin. At this time, since the PET film of the film forming substrate does not permeate the coagulation liquid, the substitution of DMF and water occurs on the skin layer 2a side, and the foam 4 having a larger film forming substrate side than the skin layer 2a side is formed. .
ここで、ポリウレタン樹脂の再生に伴う発泡形成について説明する。ポリウレタン樹脂では凝集力が大きくなるために皮膜の直近のポリウレタン樹脂中で急速に再生が進行し、スキン層２ａが形成される。本例では、凝固液に水のみが使用されており、かつ、凝固液の温度が比較的低温の１５〜２０℃に設定されている。このため、水と接触する部分でポリウレタン樹脂溶液が急速に凝固し表面に緻密なスキン層が形成されることから、水とＤＭＦとの相互拡散が抑制される。一方、ポリウレタン樹脂の濃度が１０〜３０重量％の範囲に調整されているため、凝固スピードが緩やかとなる。従って、ポリウレタン樹脂溶液内への水の浸透量が少なくなり、ポリウレタン樹脂の再生が緩慢に進行する。また、ポリウレタン樹脂溶液の粘度が３〜１０Ｐａ・ｓの範囲に調整されている。このため、凝固液中で先に再生するスキン層２ａ側と、不完全な再生状態の成膜基材側とで粘性の差が大きくなることで、上部層Ｐｈでの発泡４が傾斜するように形成されることとなる。さらに、ＤＭＦのポリウレタン樹脂溶液からの脱溶媒、すなわち、ＤＭＦと水との置換により、スキン層２ａ、発泡４および小発泡が形成され、スキン層２ａの微多孔、発泡４および小発泡が網目状に連通する。 Here, the foam formation associated with the regeneration of the polyurethane resin will be described. Since the cohesive force of the polyurethane resin is increased, the regeneration proceeds rapidly in the polyurethane resin immediately adjacent to the film, and the skin layer 2a is formed. In this example, only water is used for the coagulation liquid, and the temperature of the coagulation liquid is set to a relatively low temperature of 15 to 20 ° C. For this reason, since the polyurethane resin solution rapidly solidifies at the portion in contact with water and a dense skin layer is formed on the surface, mutual diffusion between water and DMF is suppressed. On the other hand, since the concentration of the polyurethane resin is adjusted to a range of 10 to 30% by weight, the coagulation speed becomes slow. Accordingly, the amount of water penetrating into the polyurethane resin solution is reduced, and regeneration of the polyurethane resin proceeds slowly. Moreover, the viscosity of the polyurethane resin solution is adjusted to a range of 3 to 10 Pa · s. For this reason, the foaming 4 in the upper layer Ph seems to be inclined by increasing the difference in viscosity between the skin layer 2a side to be regenerated first in the coagulation liquid and the incompletely regenerated film forming substrate side. Will be formed. Further, by removing DMF from the polyurethane resin solution, that is, by replacing DMF with water, the skin layer 2a, foam 4 and small foam are formed, and the skin layer 2a is microporous, foam 4 and small foam. Communicate with.
また、成膜基材に塗布されたポリウレタン樹脂溶液が連続的に凝固液中に案内される。このとき、凝固液中におけるポリウレタン樹脂溶液の搬送スピードを５〜１０ｍ／ｍｉｎに設定する。この搬送スピードが従来の搬送スピード（１〜２ｍ／ｍｉｎ程度）と比べて速いため、図４（Ａ）に示すように、上部層Ｐｈ側では、発泡４が成膜基材の進行方向（図４（Ａ）の矢印方向）に対して前方側に傾斜するように形成される。換言すれば、上部層Ｐｈにおける発泡４は、スキン層２ａ側の発泡端部までの発泡形成方向が厚み方向に対して成膜基材の長手方向、すなわち、成膜基材上に再生するポリウレタン樹脂の長手方向に傾斜するように形成される。また、図４（Ｂ）に示すように、発泡４は、ポリウレタン樹脂の長手方向と交差する幅方向の断面から見たときは、垂直方向、すなわち、厚み方向に沿うように形成される。換言すれば、発泡４は、上部層Ｐｈでは厚み方向に対して一定方向に一様に傾斜するように形成され、下部層Ｐｒでは厚み方向に沿うように形成される。なお、ポリウレタン樹脂が成膜基材上で再生されることから、成膜基材の表面に接触して形成された裏面Ｓｒでは、発泡４の開口は形成されていない。 Further, the polyurethane resin solution applied to the film forming substrate is continuously guided into the coagulating liquid. At this time, the conveyance speed of the polyurethane resin solution in the coagulation liquid is set to 5 to 10 m / min. Since this conveyance speed is faster than the conventional conveyance speed (about 1 to 2 m / min), as shown in FIG. 4A, on the upper layer Ph side, the foam 4 is in the traveling direction of the film forming substrate (FIG. 4 (A) in the direction of the arrow). In other words, the foam 4 in the upper layer Ph is a polyurethane in which the foam formation direction to the foam end on the skin layer 2a side is the longitudinal direction of the film forming substrate with respect to the thickness direction, that is, the polyurethane regenerated on the film forming substrate. It is formed so as to be inclined in the longitudinal direction of the resin. As shown in FIG. 4B, the foam 4 is formed along the vertical direction, that is, the thickness direction when viewed from the cross section in the width direction intersecting the longitudinal direction of the polyurethane resin. In other words, the foam 4 is formed so as to uniformly incline in a certain direction with respect to the thickness direction in the upper layer Ph, and is formed along the thickness direction in the lower layer Pr. Since the polyurethane resin is regenerated on the film forming substrate, the opening of the foam 4 is not formed on the back surface Sr formed in contact with the surface of the film forming substrate.
洗浄・乾燥工程では、再生工程で再生したポリウレタン樹脂を水等の洗浄液中で洗浄してポリウレタン樹脂中に残留するＤＭＦを除去した後、乾燥させる。ポリウレタン樹脂の乾燥には、本例では、内部に熱源を有するシリンダを備えたシリンダ乾燥機を用いる。ポリウレタン樹脂がシリンダの周面に沿って通過することで乾燥する。得られたウレタンシート２をロール状に巻き取る。 In the washing / drying step, the polyurethane resin regenerated in the regeneration step is washed in a washing solution such as water to remove DMF remaining in the polyurethane resin, and then dried. In the present example, a cylinder dryer provided with a cylinder having a heat source is used for drying the polyurethane resin. The polyurethane resin is dried by passing along the peripheral surface of the cylinder. The obtained urethane sheet 2 is wound up into a roll.
ラミネート工程では、湿式凝固法で作製されたウレタンシート２と、両面テープ７とを貼り合わせる。このとき、ウレタンシート２の裏面Ｓｒと両面テープ７とを貼り合わせる。そして、円形や角形等の所望の形状、サイズに裁断した後、キズや汚れ、異物等の付着がないことを確認する等の検査を行い、保持パッド１０を完成させる。 In the laminating step, the urethane sheet 2 produced by the wet coagulation method and the double-sided tape 7 are bonded together. At this time, the back surface Sr of the urethane sheet 2 and the double-sided tape 7 are bonded together. Then, after cutting into a desired shape or size such as a circle or a square, an inspection is performed to confirm that there is no adhesion of scratches, dirt, foreign matter, etc., and the holding pad 10 is completed.
（作用等）
次に、本実施形態の保持パッド１０の作用等について説明する。
(Action etc.)
Next, the operation and the like of the holding pad 10 of this embodiment will be described.
説明をわかりやすくするために、従来湿式凝固法により形成されるウレタンシートの発泡構造について説明する。従来湿式凝固法では、ＰＥＴ製フィルム等の成膜基材上に塗布されたポリウレタン樹脂溶液が水等の凝固液中で凝固する。このため、図５に示すように、従来の保持パッド２０を構成するウレタンシート１２では、湿式凝固時の初期に形成されたスキン層１２ａより内側に、ウレタンシート１２の厚み全体にわたる多数の発泡１４が形成される。この発泡１４は、保持面Ｓｈ側が裏面Ｓｒ側より縮径されており、厚み方向に沿うように垂直方向に形成されている。 In order to make the explanation easy to understand, a foamed structure of a urethane sheet formed by a conventional wet coagulation method will be described. In the conventional wet coagulation method, a polyurethane resin solution applied on a film forming substrate such as a PET film coagulates in a coagulation liquid such as water. Therefore, as shown in FIG. 5, in the urethane sheet 12 constituting the conventional holding pad 20, a large number of foams 14 over the entire thickness of the urethane sheet 12 are formed inside the skin layer 12 a formed at the initial stage during wet coagulation. Is formed. The foam 14 has a holding surface Sh side that is reduced in diameter from the back surface Sr side, and is formed in a vertical direction along the thickness direction.
また、ウレタンシート１２では、保持面Ｓｈ近傍で保持面Ｓｈと平行な断面に発泡１４により形成された孔の中心をとおる垂直線が裏面Ｓｒ近傍で裏面Ｓｒと平行な断面と交わる位置が裏面Ｓｒと平行な断面に同じ発泡１４で形成された孔の内部に位置する。すなわち、図６（Ａ）に示すように、保持面Ｓｈの近傍である保持面Ｓｈから５０〜１００μｍ程度内側の位置（矢印ｌの位置）、ウレタンシート１２の厚み方向中央の位置（矢印ｍの位置）、裏面Ｓｒ近傍である裏面Ｓｒから５０〜１００μｍ程度内側の位置（矢印ｎの位置）とする。この場合、図６（Ｂ）に示すように、保持面Ｓｈ近傍のｌ−ｌ断面では、発泡１４により、中心Ｍａの孔Ｈａが形成される。同様に、ウレタンシート１２の厚み方向中央部のｍ−ｍ断面では同じ発泡１４により中心Ｍｂの孔Ｈｂが形成され、裏面Ｓｒ近傍のｎ−ｎ断面では同じ発泡１４により中心Ｍｃの孔Ｈｃが形成される。孔Ｈａの中心Ｍａ、孔Ｈｂの中心Ｍｂ、孔Ｈｃの中心Ｍｃは、厚み方向にほぼ揃うように位置している。つまり、孔Ｈａの中心Ｍａをとおる垂直線Ｌがｎ−ｎ断面と交点Ｑで交わる。このため、交点Ｑは孔Ｈｃの内部に位置することとなる。 In the urethane sheet 12, the position where the vertical line passing through the center of the hole formed by the foam 14 in the cross section parallel to the holding surface Sh near the holding surface Sh intersects the cross section parallel to the back surface Sr near the back surface Sr. It is located inside a hole formed by the same foam 14 in a cross section parallel to. That is, as shown in FIG. 6 (A), a position about 50 to 100 μm from the holding surface Sh that is in the vicinity of the holding surface Sh (position of the arrow l), a center position in the thickness direction of the urethane sheet 12 (of the arrow m). Position), and a position about 50 to 100 μm from the back surface Sr in the vicinity of the back surface Sr (position of arrow n). In this case, as shown in FIG. 6B, a hole Ha of the center Ma is formed by the foaming 14 in the l-l cross section in the vicinity of the holding surface Sh. Similarly, the hole Hb of the center Mb is formed by the same foaming 14 in the mm section at the central portion in the thickness direction of the urethane sheet 12, and the hole Hc of the center Mc is formed by the same foaming 14 in the nn section near the back surface Sr. Is done. The center Ma of the hole Ha, the center Mb of the hole Hb, and the center Mc of the hole Hc are positioned so as to be substantially aligned in the thickness direction. That is, the vertical line L passing through the center Ma of the hole Ha intersects the nn cross section at the intersection Q. For this reason, the intersection point Q is located inside the hole Hc.
このようなウレタンシート１２を用いた従来の保持パッド２０では、研磨加工時に研磨圧がかけられると、被研磨物が保持パッド２０側に沈み込むため、クッション性を有するウレタンシート１２が圧縮されることで被研磨物に対して応力が発生する。保持パッド２０の密度にバラツキがある場合、すなわち、発泡１４の形成にムラがある場合は、密度のバラツキ部分ごとに被研磨物にかかる応力の大きさが異なることとなる。このため、被研磨物に対する押圧力が局所的に変わるため、被研磨物の加工面を全域にわたって均一に研磨加工することが難しくなる。この結果、研磨加工後の被研磨物では、例えば、外縁部と中央部とで研磨取り代が異なり、いわゆる縁だれが生じることがある。換言すれば、保持パッド２０で被研磨物を保持させて研磨加工することで、加工面の平坦性を損なうことがある。従って、従来の保持パッド２０では、欠陥のない積層配線の高集積化や高画質画像を演出することを目的とした半導体用ＷＦやＦＰＤ用ガラス基板に要求される高精度な平坦性を満たすには十分とはいえない。 In the conventional holding pad 20 using such a urethane sheet 12, when the polishing pressure is applied during the polishing process, the object to be polished sinks to the holding pad 20 side, so the urethane sheet 12 having cushioning properties is compressed. As a result, stress is generated on the object to be polished. When the density of the holding pad 20 varies, that is, when the formation of the foam 14 is uneven, the magnitude of stress applied to the object to be polished differs for each density variation portion. For this reason, since the pressing force against the object to be polished changes locally, it becomes difficult to uniformly polish the processed surface of the object to be polished over the entire area. As a result, in the object to be polished after the polishing process, for example, the polishing allowance differs between the outer edge portion and the central portion, and so-called edge drooping may occur. In other words, holding the object to be polished by the holding pad 20 for polishing may impair the flatness of the processed surface. Therefore, the conventional holding pad 20 satisfies the high-precision flatness required for a semiconductor WF or FPD glass substrate for the purpose of producing a high-density image with no defects and producing a high-quality image. Is not enough.
これに対して、本実施形態では、ウレタンシート２に形成される発泡４は、上部層Ｐｈで厚み方向に対して一定方向に一様に傾斜するように形成されており、下部層Ｐｒで厚み方向に沿うように形成されている。このため、湿式凝固時にウレタンシート２に密度ムラが生じても、研磨加工時に圧縮されたときに被研磨物に対する応力を均等化することができる。これは、発泡４の形状が下部層Ｐｒでの形成位置に対して保持面Ｓｈ側の位置がズレているためと考えられる。すなわち、保持面Ｓｈで受けた圧縮力に対して、下部層Ｐｒ側で近接して形成された複数の発泡４が総合的に伸縮することで、密度ムラを顕在化させることなく被研磨物に与える応力ムラを低減することができたためと考えられる。従って、保持面の平坦性精度が高められ被研磨物に対する応力が均等化されるため、被研磨物の面内均一性を向上させ高度に平滑化することができる。 On the other hand, in the present embodiment, the foam 4 formed on the urethane sheet 2 is formed so as to uniformly incline in a certain direction with respect to the thickness direction in the upper layer Ph, and has a thickness in the lower layer Pr. It is formed along the direction. For this reason, even if density unevenness occurs in the urethane sheet 2 during wet coagulation, the stress on the object to be polished can be equalized when compressed during polishing. This is presumably because the position of the foam 4 is shifted on the holding surface Sh side with respect to the formation position of the lower layer Pr. That is, the plurality of foams 4 formed close to each other on the lower layer Pr side with respect to the compressive force received on the holding surface Sh expand and contract comprehensively, so that the object to be polished can be obtained without revealing density unevenness. This is thought to be because the stress unevenness to be applied could be reduced. Therefore, since the flatness accuracy of the holding surface is improved and the stress on the object to be polished is equalized, the in-plane uniformity of the object to be polished can be improved and highly smoothed.
また、発泡４が、上部層Ｐｈから下部層Ｐｒにわたって全体的に傾斜して形成された場合は、研磨加工時の圧縮力により保持パッド自体が断面斜方状に変形し被研磨物に対する応力を均等化することが難しくなる。発泡４が一定方向に一様に傾斜して形成されずランダムに傾斜して形成された場合は、下部層Ｐｒで肥大化していても、却って応力ムラが増大するおそれがある。これに対して本実施形態では、発泡４が一定方向に一様に傾斜するように形成されているため、応力ムラを低減し被研磨物の平坦性を向上させることができる。 Further, when the foam 4 is formed so as to be entirely inclined from the upper layer Ph to the lower layer Pr, the holding pad itself is deformed in an oblique cross section due to the compressive force at the time of polishing, and stress on the object to be polished is caused. It becomes difficult to equalize. When the foam 4 is not formed with a uniform inclination in a certain direction but is formed with a random inclination, even if the foam 4 is enlarged in the lower layer Pr, the stress unevenness may increase. On the other hand, in this embodiment, since the foam 4 is formed so as to be uniformly inclined in a certain direction, the stress unevenness can be reduced and the flatness of the object to be polished can be improved.
更に、本実施形態では、発泡４における中心Ｍ１と頂点Ｍ２とを結ぶ線分を斜辺とする直角三角形で中心Ｍ１から頂点Ｍ２を見たときの仰角θが３０〜６０度の範囲、すなわち、ｔａｎθが０．５８〜１．７３の範囲となるように発泡４が形成されている。このため、保持面Ｓｈに対する局所的な圧縮力が下部層Ｐｒ側で近接して形成された複数の発泡４で緩和されるので、被研磨物に対する応力ムラを確実に低減することができる。被研磨物の面内均一性を向上させることを考慮すれば、仰角θが４０〜５５度の範囲、すなわち、ｔａｎθが０．８４〜１．４３の範囲の範囲となるように、発泡４が形成されていることが好ましい。 Furthermore, in the present embodiment, the elevation angle θ when the vertex M2 is viewed from the center M1 in a right triangle having a hypothetical line segment connecting the center M1 and the vertex M2 in the foam 4 is in a range of 30 to 60 degrees, that is, tan θ. The foam 4 is formed so that is in the range of 0.58 to 1.73. For this reason, since the local compressive force with respect to the holding surface Sh is relieved by the plurality of foams 4 formed close to each other on the lower layer Pr side, the stress unevenness to the object to be polished can be surely reduced. In consideration of improving the in-plane uniformity of the object to be polished, the foam 4 is formed so that the elevation angle θ is in the range of 40 to 55 degrees, that is, the tan θ is in the range of 0.84 to 1.43. Preferably it is formed.
また更に、本実施形態では、発泡４は、下部層Ｐｒでの孔径が上部層Ｐｈでの孔径より大きく形成されている。このため、研磨加工時に研磨圧がかけられたときに、クッション性を確保することができる。また、発泡４が上部層Ｐｈで傾斜するように形成されているため、被研磨物にかかる研磨圧が均等化され、被研磨物の保持パッド１０側への沈み込みを抑制することができる。このため、沈み込みが大きくなると保持パッド自体が研削されるのに対して、保持パッド２０自体が研削されることを抑制することができる。これにより、保持面Ｓｈの平坦性を確保しつつ被研磨物の平坦性向上を図ることができる。更にまた、通常、研磨加工では、保持面の平坦性を向上させるために慣らし時間を要する。これに対して、保持パッド２０を用いた研磨加工では、保持面Ｓｈの平坦性が確保されているため、慣らし時間の短縮化を図ることができ、生産効率の向上を図ることができる。 Furthermore, in the present embodiment, the foam 4 is formed such that the hole diameter in the lower layer Pr is larger than the hole diameter in the upper layer Ph. For this reason, cushioning properties can be ensured when a polishing pressure is applied during polishing. Further, since the foam 4 is formed so as to be inclined at the upper layer Ph, the polishing pressure applied to the object to be polished is equalized, and the sinking of the object to be polished toward the holding pad 10 can be suppressed. For this reason, when the sinking is increased, the holding pad itself is ground, whereas the holding pad 20 itself can be prevented from being ground. Thereby, the flatness of the workpiece can be improved while ensuring the flatness of the holding surface Sh. Furthermore, in general, in the polishing process, a break-in time is required to improve the flatness of the holding surface. On the other hand, in the polishing process using the holding pad 20, since the flatness of the holding surface Sh is ensured, the break-in time can be shortened and the production efficiency can be improved.
なお、本実施形態では、保持パッド２０を構成するウレタンシート２がポリウレタン樹脂製の例を示したが、本発明はこれに限定されるものではない。保持パッド２０としては、樹脂製のシートを備えていればよく、被研磨物を保持するためにクッション性や適正な硬度を有していればよい。樹脂製シートとしては、ポリウレタン樹脂に代えて、ポリエステルやポリエチレン等を用いるようにしてもよい。クッション性や硬度等を考慮すれば、湿式凝固法により形成される発泡構造を有するシートが好ましい。 In the present embodiment, the urethane sheet 2 constituting the holding pad 20 is made of polyurethane resin, but the present invention is not limited to this. The holding pad 20 may be provided with a resin sheet, and may have a cushioning property or appropriate hardness in order to hold an object to be polished. As the resin sheet, polyester or polyethylene may be used instead of polyurethane resin. In view of cushioning properties, hardness and the like, a sheet having a foam structure formed by a wet coagulation method is preferable.
また、本実施形態では、湿式凝固法における条件、例えば、ポリウレタン樹脂溶液の濃度や温度、凝固液中での搬送速度等を変えることで、上部層Ｐｈと下部層Ｐｒとの厚み割合を変えることができる。すなわち、ウレタンシート２の厚み方向中央部としては、ウレタンシート２の全体の厚みに対して厚み方向の中心から±１０％の範囲で変えることができる。研磨加工時のクッション性確保や被研磨物に対する応力ムラの低減を考慮すれば、ウレタンシート２の厚み方向のほぼ中央に上部層Ｐｈと下部層Ｐｒとの境界が位置していることが好ましい。 In this embodiment, the thickness ratio between the upper layer Ph and the lower layer Pr is changed by changing the conditions in the wet coagulation method, for example, the concentration and temperature of the polyurethane resin solution, the conveyance speed in the coagulation liquid, and the like. Can do. That is, the thickness direction central portion of the urethane sheet 2 can be changed within a range of ± 10% from the thickness direction center with respect to the entire thickness of the urethane sheet 2. In consideration of securing cushioning properties during polishing and reducing stress unevenness with respect to the object to be polished, it is preferable that the boundary between the upper layer Ph and the lower layer Pr is located substantially at the center in the thickness direction of the urethane sheet 2.
更に、本実施形態では、基材としてＰＥＴ製フィルムを有し、基材の両面に粘着剤層が形成された両面テープ７を例示したが、本発明は基材や粘着剤の材質に制限されるものではない。また、ポリウレタン樹脂溶液の溶媒、成膜基材、凝固液等の具体例を示したが、本発明はこれらに限定されるものではなく、通常用いられる材料を用いてもよいことはもちろんである。 Furthermore, in this embodiment, the double-sided tape 7 having a PET film as a base material and having a pressure-sensitive adhesive layer formed on both sides of the base material is exemplified, but the present invention is limited to the material of the base material and the pressure-sensitive adhesive. It is not something. Further, specific examples of the solvent of the polyurethane resin solution, the film forming base material, the coagulating liquid, etc. have been shown, but the present invention is not limited to these, and it is of course possible to use a commonly used material. .
また更に、本実施形態では、特に言及していないが、湿式凝固法により形成されたウレタンシート２の厚みバラツキが大きくなったときは、保持面Ｓｈと裏面Ｓｒとが平行となるように、裏面Ｓｒ側をバフやスライス等の方法により平滑にしておくことが好ましい。このようにすれば、保持面Ｓｈの平坦性を一層向上させることができる。 Furthermore, in this embodiment, although not particularly mentioned, when the thickness variation of the urethane sheet 2 formed by the wet coagulation method is increased, the holding surface Sh and the back surface Sr are parallel to each other. It is preferable to smooth the Sr side by a method such as buffing or slicing. In this way, the flatness of the holding surface Sh can be further improved.
次に、本実施形態に従い製造した保持パッド１０の実施例について説明する。なお、比較のために製造した比較例についても併記する。 Next, examples of the holding pad 10 manufactured according to the present embodiment will be described. A comparative example manufactured for comparison is also shown.
（実施例１）
実施例１では、ウレタンシート２の作製にポリエステルＭＤＩ（ジフェニルメタンジイソシアネート）ポリウレタン樹脂を用い、ＤＭＦに２０重量％の割合で溶解させた溶液の１００部に対して、ＤＭＦの４５部、顔料としてカーボンブラックを２０重量％含むＤＭＦ分散液の４０部を添加し混合してポリウレタン樹脂溶液を調製した。得られたポリウレタン樹脂溶液の粘度は、３．４Ｐａ・ｓであった。この粘度は、回転粘度計（東機産業株式会社製、ＴＶＢ−１０型）でＮｏ．Ｍ３のロータを使用し、２５℃の温度環境下で測定した値である。ポリウレタン樹脂溶液を塗布する際に塗布装置のクリアランスを１．０ｍｍに設定した。ＰＥＴ製フィルムの成膜基材にポリウレタン樹脂溶液を塗布した後、温度２０℃の水（凝固液）に連続的に案内した。このとき、ポリウレタン樹脂溶液の搬送スピード（ラインスピード）を７ｍ／ｍｉｎに設定し、ポリウレタン樹脂を完全に再生させた。洗浄、乾燥後、得られたウレタンシート２の裏面Ｓｒ側にバフィングし、バフ面に両面テープ７を貼り合わせ保持パッド１０を製造した。
Example 1
In Example 1, a polyester MDI (diphenylmethane diisocyanate) polyurethane resin was used for the production of the urethane sheet 2, and 45 parts of DMF and carbon black as a pigment were added to 100 parts of a solution dissolved in 20% by weight in DMF. A polyurethane resin solution was prepared by adding and mixing 40 parts of a DMF dispersion containing 20% by weight. The viscosity of the obtained polyurethane resin solution was 3.4 Pa · s. This viscosity was measured using a rotational viscometer (Toki Sangyo Co., Ltd., TVB-10 type). It is a value measured under a temperature environment of 25 ° C. using an M3 rotor. When applying the polyurethane resin solution, the clearance of the coating device was set to 1.0 mm. After applying the polyurethane resin solution to the PET film-forming substrate, it was continuously guided to water (coagulating liquid) at a temperature of 20 ° C. At this time, the conveyance speed (line speed) of the polyurethane resin solution was set to 7 m / min, and the polyurethane resin was completely regenerated. After washing and drying, buffing was performed on the back surface Sr side of the obtained urethane sheet 2, and the double-sided tape 7 was bonded to the buff surface to manufacture the holding pad 10.
(実施例２)
実施例２では、ポリウレタン樹脂溶液のラインスピードを５ｍ／ｍｉｎに設定した以外は、実施例１と同様にしてウレタンシート２を作製し、保持パッド１０を製造した。用いたポリウレタン樹脂溶液の粘度は３．２Ｐａ・ｓであった。
(Example 2)
In Example 2, a urethane sheet 2 was produced in the same manner as in Example 1 except that the line speed of the polyurethane resin solution was set to 5 m / min, and a holding pad 10 was produced. The viscosity of the polyurethane resin solution used was 3.2 Pa · s.
（比較例１）
比較例１では、ポリエステルＭＤＩポリウレタン樹脂をＤＭＦに３０重量％の割合で溶解させ、凝固液中でのラインスピードを１．５ｍ／ｍｉｎに設定した以外は実施例１と同様にしてウレタンシート１２を作製し保持パッド２０を製造した。ポリウレタン樹脂溶液の粘度は８．２Ｐａ・ｓであった。すなわち、比較例１の保持パッド２０は、従来の保持パッドである（図５も参照）。
(Comparative Example 1)
In Comparative Example 1, the urethane sheet 12 was prepared in the same manner as in Example 1 except that the polyester MDI polyurethane resin was dissolved in DMF at a rate of 30% by weight and the line speed in the coagulation liquid was set to 1.5 m / min. The produced holding pad 20 was manufactured. The viscosity of the polyurethane resin solution was 8.2 Pa · s. That is, the holding pad 20 of Comparative Example 1 is a conventional holding pad (see also FIG. 5).
得られた実施例１および比較例１のウレタンシートについて、三次元計測Ｘ線ＣＴ装置にて内部構造を非破壊で可視化し、発泡の形成状態を比較した。すなわち、三次元計測Ｘ線ＣＴ装置（ヤマト科学製、ＴＤＭ１０００−ＩＳ／ＳＰ）を用いてスキャンし、保持面Ｓｈから１０μｍ間隔の連続断層画像を得た。得られた断層画像をＳＥＭ用画像解析ソフトウエア『Ｓｃａｎｄｉｕｍ』（Ｏｌｙｍｐｕｓ Ｓｏｆｔ−Ｉｍａｇｉｎｇ Ｓｏｌｕｔｉｏｎｓ社製）に取り込み、注目した１つの発泡４（比較例１では発泡１４。以下、同じ。）について、各断面画像の発泡中心（重心）を求めた。次に、発泡４の頂点Ｍ２が観察された断面画像の保持面Ｓｈからの距離、および、厚み方向中央で中心Ｍ１の孔が形成された断面画像の保持面Ｓｈからの距離から、２つの断面間の距離ｙを得た。また、中心Ｍ１をとおり厚み方向と直交する方向の直線と、頂点Ｍ２をとおる厚み方向の直線との交点をＰとしたときの中心Ｍ１と交点Ｐとの距離ｘを得た（図３も参照）。得られた距離ｘ、距離ｙの数値から求めたｔａｎθの値は、実施例１、実施例２がそれぞれ０．９３、１．２８、比較例１が９．５１であった。得られたｔａｎθの値から発泡の傾斜角である仰角θを換算したところ、実施例１、実施例２がそれぞれ４３度、５２度、比較例１が８４度を示し、実施例１、実施例２の発泡が比較例１の発泡より大きく傾斜していることが判った。連続断層画像解析によるｔａｎθの測定結果から明らかなように、比較例１のウレタンシート１２では、厚み全体にわたり厚み方向に沿うように発泡が形成されていた（図６も参照）。つまり、厚み方向中央部よりスキン層側では、若干の傾斜は見られるものの、発泡形成方向がほぼ厚み方向に沿って形成されていた。これに対して、実施例１のウレタンシート２では、上部層Ｐｈでの発泡形成方向が比較例１と比べて大きく傾斜していることが判明した（図２も参照）。 About the obtained urethane sheet of Example 1 and Comparative Example 1, the internal structure was visualized in a non-destructive manner with a three-dimensional measurement X-ray CT apparatus, and the formation state of foam was compared. That is, scanning was performed using a three-dimensional measurement X-ray CT apparatus (manufactured by Yamato Kagaku, TDM1000-IS / SP), and continuous tomographic images at intervals of 10 μm were obtained from the holding surface Sh. The obtained tomographic image is taken into SEM image analysis software “Scandium” (manufactured by Olympus Soft-Imaging Solutions) and focused on one foam 4 (foam 14 in Comparative Example 1; the same applies hereinafter). The foam center (center of gravity) of the image was determined. Next, from the distance from the holding surface Sh of the cross-sectional image where the vertex M2 of the foam 4 is observed and the distance from the holding surface Sh of the cross-sectional image in which the hole of the center M1 is formed at the center in the thickness direction, two cross sections are obtained. A distance y between was obtained. Further, a distance x between the center M1 and the intersection point P was obtained when the intersection point of the straight line in the direction perpendicular to the thickness direction passing through the center M1 and the straight line in the thickness direction passing through the vertex M2 was defined as P (see also FIG. 3). ). The values of tan θ obtained from the numerical values of the obtained distance x and distance y were 0.93 and 1.28 in Example 1 and Example 2, respectively, and 9.51 in Comparative Example 1. When the elevation angle θ, which is the inclination angle of foaming, was converted from the obtained tan θ value, Example 1 and Example 2 showed 43 degrees and 52 degrees, and Comparative Example 1 showed 84 degrees. Example 1 and Example It was found that the foaming of 2 was more greatly inclined than the foaming of Comparative Example 1. As is clear from the measurement result of tan θ by continuous tomographic image analysis, in the urethane sheet 12 of Comparative Example 1, foaming was formed along the thickness direction over the entire thickness (see also FIG. 6). That is, although a slight inclination is seen on the skin layer side from the central portion in the thickness direction, the foam formation direction is formed substantially along the thickness direction. On the other hand, in the urethane sheet 2 of Example 1, it was found that the foam formation direction in the upper layer Ph was greatly inclined as compared with Comparative Example 1 (see also FIG. 2).
（研磨性能評価）
各実施例および比較例の保持パッドを用いて、以下の研磨条件で液晶ディスプレイ用ガラス基板（４７０ｍｍ×３７０ｍｍ×０．７ｍｍ）の研磨加工を行い、日本工業規格（ＪＩＳ Ｂ ０６０１：’８２））に準じた方法で、ろ波中心うねりから平坦度ａを求めた。平坦度ａの測定では、表面粗さ形状測定機（株式会社東京精密製、サーフコム４８０Ａ）を使用し、以下の測定条件で測定した。基板表面の凹凸に起因して得られる測定曲線から、隣り合う凸部（山部）と凸部との間の幅Ｗ、および、凸部と凹部（谷部）との高さＳを算出し、幅Ｗを横軸、高さＳを縦軸とした散布図を作成した。散布図から、一次式Ｓ＝ａＷの近似直線を求め、傾きａを研磨加工後の最終の平坦度ａとした。平坦性が高くなるほど幅Ｗが大きくなり、高さＳが小さくなるため、傾きａが小さいほど平坦性に優れることを示すこととなる。
（研磨条件）
使用研磨機：オスカー研磨機（スピードファム社製、ＳＰ−１２００）
研磨速度（回転数）：６１ｒｐｍ
加工圧力：１００ｇ／ｃｍ２
スラリ：セリウムスラリ
研磨時間：３０ｍｉｎ
（ろ波中心うねり測定条件）
評価長さ：９０ｍｍ
測定速度：３．０ｍｍ／ｓ
カットオフ値：０．８〜８．０ｍｍ
フィルタ種別：２ＲＣ
測定レンジ：±４０．０μｍ
傾斜補正：スプライン
(Polishing performance evaluation)
A glass substrate for liquid crystal display (470 mm × 370 mm × 0.7 mm) was polished under the following polishing conditions using the holding pads of each Example and Comparative Example, and Japanese Industrial Standard (JIS B 0601: '82)) The flatness a was obtained from the filtered wave center waviness. In the measurement of flatness a, a surface roughness shape measuring machine (manufactured by Tokyo Seimitsu Co., Ltd., Surfcom 480A) was used, and measurement was performed under the following measurement conditions. From the measurement curve obtained due to the unevenness of the substrate surface, the width W between the adjacent convex part (peak part) and the convex part and the height S between the convex part and the concave part (valley part) are calculated. A scatter diagram was created with the width W as the horizontal axis and the height S as the vertical axis. From the scatter diagram, an approximate straight line of the primary expression S = aW was obtained, and the inclination a was defined as the final flatness a after polishing. The higher the flatness, the larger the width W and the smaller the height S. Therefore, the smaller the inclination a, the better the flatness.
(Polishing conditions)
Polishing machine used: Oscar polishing machine (SP-1200, manufactured by Speed Fam Co., Ltd.)
Polishing speed (rotation speed): 61 rpm
Processing pressure: 100 g / cm 2
Slurry: Cerium slurry polishing time: 30 min
(Filter center swell measurement conditions)
Evaluation length: 90mm
Measurement speed: 3.0 mm / s
Cut-off value: 0.8-8.0mm
Filter type: 2RC
Measurement range: ± 40.0μm
Tilt correction: Spline
実施例１、実施例２の保持パッド１０、比較例１の保持パッド２０をそれぞれ用いた研磨加工による平坦度ａを比較すると、研磨時間３０ｍｉｎ後に、実施例１、実施例２ではそれぞれ０．０００４、０．０００６を示し、比較例１では０．００１２を示した。すなわち、実施例１、実施例２では、比較例１と比べて、最終的な平坦度ａを向上させることができた。従って、湿式凝固法により形成された発泡４が、上部層Ｐｈで厚み方向に対して一定方向に一様に傾斜するように形成され、下部層Ｐｒで厚み方向に沿うように形成されたウレタンシート２を備えた保持パッド１０を用いることで、保持面の平坦性精度を高めるとともに、被研磨物の面内均一性を向上させることができることが明らかとなった。 When the flatness a by polishing using the holding pad 10 of Example 1 and Example 2 and the holding pad 20 of Comparative Example 1 is compared, 0.0004 is obtained in Example 1 and Example 2 after 30 minutes of polishing time. 0.0006 and Comparative Example 1 showed 0.0012. That is, in Example 1 and Example 2, the final flatness a could be improved as compared with Comparative Example 1. Therefore, the urethane sheet formed by the wet coagulation method is formed such that the foam 4 is uniformly inclined in a certain direction with respect to the thickness direction in the upper layer Ph, and is formed in the thickness direction in the lower layer Pr. It was revealed that the use of the holding pad 10 with 2 can improve the flatness accuracy of the holding surface and improve the in-plane uniformity of the object to be polished.
本発明は保持面の平坦性精度を高め被研磨物の面内均一性を向上させることができる保持パッドを提供するものであるため、保持パッドの製造、販売に寄与するので、産業上の利用可能性を有する。 Since the present invention provides a holding pad that can improve the flatness accuracy of the holding surface and improve the in-plane uniformity of the object to be polished, it contributes to the manufacture and sale of the holding pad. Have potential.
Ｓｈ 保持面
Ｓｒ 裏面（背面）
２ ウレタンシート（樹脂シート）
２ａ スキン層
４ 発泡
１０ 保持パッド
Sh Holding surface Sr Back (Back)
2 Urethane sheet (resin sheet)
2a Skin layer 4 Foam 10 Holding pad
Claims (9)
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009204003A JP5355310B2 (en) | 2009-09-03 | 2009-09-03 | Holding pad |
| TW98132166A TWI432287B (en) | 2009-09-03 | 2009-09-23 | Keep the pad |
| PCT/JP2009/004791 WO2011027411A1 (en) | 2009-09-03 | 2009-09-24 | Supporting pad |
| KR1020127001320A KR101588925B1 (en) | 2009-09-03 | 2009-09-24 | Retaining pad |
| CN200980160742.8A CN102481679B (en) | 2009-09-03 | 2009-09-24 | Supporting pad |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009204003A JP5355310B2 (en) | 2009-09-03 | 2009-09-03 | Holding pad |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2011051074A JP2011051074A (en) | 2011-03-17 |
| JP5355310B2 true JP5355310B2 (en) | 2013-11-27 |
Family
ID=43648974
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2009204003A Active JP5355310B2 (en) | 2009-09-03 | 2009-09-03 | Holding pad |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP5355310B2 (en) |
| KR (1) | KR101588925B1 (en) |
| CN (1) | CN102481679B (en) |
| TW (1) | TWI432287B (en) |
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| JP5484145B2 (en) * | 2010-03-24 | 2014-05-07 | 東洋ゴム工業株式会社 | Polishing pad |
| JP5854910B2 (en) * | 2012-03-30 | 2016-02-09 | 富士紡ホールディングス株式会社 | Polishing pad |
| JP5917236B2 (en) * | 2012-03-30 | 2016-05-11 | 富士紡ホールディングス株式会社 | Polishing pad sheet and manufacturing method thereof, polishing pad and manufacturing method thereof, and polishing method |
| KR101666477B1 (en) * | 2013-06-04 | 2016-10-14 | 주식회사 엘지화학 | Preparation method of poly-urethane mounting pad and poly-urethane mounting pad |
| JP6423352B2 (en) * | 2013-09-30 | 2018-11-14 | 富士紡ホールディングス株式会社 | Holding pad |
| JP6279309B2 (en) * | 2013-12-20 | 2018-02-14 | スリーエム イノベイティブ プロパティズ カンパニー | Polishing cushion, polishing apparatus, polishing method, and article including an object polished by the polishing method |
| KR101527348B1 (en) * | 2014-03-04 | 2015-06-09 | 대원화성 주식회사 | Holding pad having enhanced durability |
| CN105269451A (en) * | 2014-07-02 | 2016-01-27 | 大元化成株式会社 | Maintaining pad having high-precision flatness |
| US20210323116A1 (en) * | 2020-04-18 | 2021-10-21 | Rohm And Haas Electronic Materials Cmp Holdings, Inc. | Offset pore poromeric polishing pad |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS5840356U (en) * | 1981-09-10 | 1983-03-16 | 株式会社三興技研 | Protective equipment for abrasive workpieces |
| JPH11277407A (en) * | 1998-03-30 | 1999-10-12 | Sony Corp | Polishing pad, polishing device, and polishing method |
| JP4189384B2 (en) * | 2002-12-26 | 2008-12-03 | Ｈｏｙａ株式会社 | Manufacturing method and polishing apparatus for glass substrate for information recording medium |
| JP2004358588A (en) * | 2003-06-03 | 2004-12-24 | Unitika Ltd | Abrasive pad and its manufacturing method |
| JP2005349502A (en) * | 2004-06-09 | 2005-12-22 | Nitta Haas Inc | Polishing object holding material |
| JP4455230B2 (en) * | 2004-08-30 | 2010-04-21 | 富士紡ホールディングス株式会社 | Holding pad and method of manufacturing the holding pad |
| JP2007160474A (en) * | 2005-12-15 | 2007-06-28 | Nitta Haas Inc | Polishing cloth and its manufacturing method |
| JP5216238B2 (en) * | 2007-05-21 | 2013-06-19 | 富士紡ホールディングス株式会社 | Holding pad and method of manufacturing holding pad |
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| WO2011027411A1 (en) | 2011-03-10 |
| TWI432287B (en) | 2014-04-01 |
| KR20120060812A (en) | 2012-06-12 |
| KR101588925B1 (en) | 2016-01-26 |
| CN102481679A (en) | 2012-05-30 |
| JP2011051074A (en) | 2011-03-17 |
| TW201109123A (en) | 2011-03-16 |
| CN102481679B (en) | 2014-06-18 |
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