JP2004339458A - Double-sided pressure-sensitive adhesive sheet and abrasive cloth layered product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abrasive cloth-fixing pressure-sensitive tape that is capable of forming an abrasive cloth laminate body that causes no marked stress relaxation in no need of many-hour immersion of the abrasive slurry before the abrasion and causes no swelling deformation due to the abrasive slurry during the abrasion and provide an abrasive cloth laminated body. <P>SOLUTION: This double-sided pressure-sensitive sheet has a thickness difference per 1 m<SP>2</SP>between the maximum thickness and the minimum thickness of ≤ 100 μm, the compression stress damping factor of ≤ 15 % that is measured from the maximum compression stress in the compression test in which the compression distance after compression is kept constant and the compression stress value after 0.1 second after the maximum value is obtained. The abrasive cloth laminated body comprises the double-sided pressure sensitive sheet and a pressure-sensitive adhesive layer that is laminated on any one face of the double-sided pressure sensitive layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３３】
前記一般式（Ｉ）中で、ｍ、ｎ、及びｐは１以上の整数であり、Ｒ^１及びＢは２価の有機基であり、Ｒ^２は水素原子又は炭素原子数１〜４のアルキル基であり、Ａは反応性基、例えば、ＯＨ基、Ｎ（Ｒ）Ｈ基（ここで、Ｒは炭素原子数１〜４のアルキル基である）、ＮＨ_２基、ＳＨ基、ＣＯＯＨ基、又はＳｉ−ＯＣＨ_３基（メトキシ基）である。反応型シリコーン整泡剤を用いることで本発明による粘着シートの発泡体層の通気性が低くなり、その結果、通常の添加型（非反応型）シリコーン整泡剤を使用する場合と比べて吸水性が大幅に低くなり、安定的な研磨が可能となる。また、その他の助剤としては、ポリウレタン製造時に使用する慣用の助剤を用いることができる。
【００３４】
上記のポリオール、ポリイソシアネート、発泡剤及び反応型シリコーン整泡剤、並びにその他の助剤を使用して、ポリウレタン発泡体を製造する方法としては、通常行なわれている水発泡方法、揮発性溶剤による発泡方法や、空気などを泡立てる方法などのいずれの方法を用いることができるが、マイクロセルとすることで、熱伝導率が下がるため、前者の２つの方法は、後者の気体泡立て方法よりもキュア−時間が短くなるので好ましい。得られるマイクロセルウレタンのセル径の調整方法としては、例えば、シリコーン整泡剤や触媒量の添加部数を増やしたり、あるいはポリオ−ルの官能基を２官能より３官能とし架橋剤の官能基数を多くしたり、発泡時の圧力を高くする等の手段によりセル径を細かくすることができる。
【００３５】
アミン触媒よりスズ触媒の方を多くすることでもセル径を細かくすることができるが、本発明においては好ましくない。ただし、被研磨物内に含有される金属や研磨のために用いる活性剤に代表される添加剤もしくは酸、塩基を含有する水溶液、又は、潤滑油に含まれる金属は含有していても差し支えない場合がある。
【００３６】
ポリウレタン発泡体は、従来公知の一般的な方法でシート状に成形することができる。例えば、特開昭５１−６７３９６号公報、特開昭５３−６３６５号公報には、押し出しダイから工程フィルム上に、反応することによってポリウレタンを形成し得る未発泡の組成物を展開し、発泡させつつオーブン内を通過させて硬化させる方法が提案されている。
【００３７】
工程フィルムに剥離処理を施した場合には、シート形成後に工程フィルムを剥離してウレタンのみの発泡体シートを得ることができる。また、工程フィルムに剥離処理を施さない場合には、ポリウレタンの発泡、硬化の過程で、ポリウレタンと工程フィルムとが強固に結合するので、この工程フィルムを後述する補強シートとして利用することができ、発泡体シートと補強シートとの間には格別接着剤層もしくは粘着剤層を設けなくても両シートを積層することができる。
また、剥離処理してなる工程フィルムを使用する場合、１枚の工程フィルムの剥離処理面に、上記組成物を展開して発泡、硬化させたり、２枚の工程フィルムの剥離処理面間に上記組成物を挟み込んでから発泡、硬化させたりする方法があるが、後者の方が好ましい。すなわち２枚の工程フィルムを用いてポリウレタン発泡体シートを形成し、両工程フィルムを剥がすと、シート両面に滑らかなスキン層を有する発泡体シートが形成される。このスキン層は、接着剤層もしくは粘着剤層を積層した場合、層間の密着性向上に効果を奏し、更に厚み精度が制御し易いため、２枚の工程フィルムを用いることが好ましい。
【００３８】
ウレタン発泡体シートの成形に使用する工程フィルムとしては、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）等の平滑性と１００℃程度の熱を数分間かけても溶融切断しないような耐熱性とを有するフィルムが用いられる。
【００３９】
上記した発泡体シートの破断強度は一般に比較的小さいので（例えば、５ＭＰａ以下）、破断強度が４０ＭＰａ以上の補強シートを、発泡体シートと一方の粘着剤層との間に設けることによって、両面粘着シートの強度を大きくすることができる。両面粘着シートの破断強度を大きくできると、例えば研磨後、研磨布ごと両面粘着シートを研磨装置から剥がしたり、又は研磨後、両面粘着シートから研磨布を剥がす際に、両面粘着シートを破損することなく剥がし易くなる。
【００４０】
補強シートは、種々のプラスチックシートであることが好ましく、厚さ精度や耐熱性、耐薬品性、汎用性の観点から好ましくはポリエチレンテレフタレートがより好ましい。
厚さは１２〜２５０μｍであることが好ましく、更に２５〜１００μｍであることがより好ましい。
【００４１】
尚、補強シートを有する場合、後述する図３〜図８に示す態様のように、両面粘着シートの積層断面構成は非対称となるが、少なくとも一方の面で測定した場合の圧縮応力減衰率が０〜１５％の範囲にあればよく、補強シートを配置した側から遠い方の粘着剤層面の圧縮応力減衰率が上記範囲にあることがより好ましい。
【００４２】
本発明において用いる粘着剤層について説明する。
本発明の両面粘着シートは、例えば、ＣＭＰ技術での研磨布と研磨装置との間に位置し、両者を貼着するために用いられるものであり、補強シートがある場合には、後述する図３〜図８に示す態様のように、積層断面構成が非対称となるので、
（Ａ）補強シートを配置した側の面から遠い方の粘着剤層に研磨布を貼着し、補強シートを配置した側の面に近い方の粘着剤層を研磨装置に貼着する、
（Ｂ）補強シートを配置した側の面から遠い方の粘着剤層を研磨装置に貼着し、補強シートを配置した側の面に近い方の粘着剤層に研磨布を貼着する、等の形態が考えられるが、（Ａ）の形態が好ましい。
（Ａ）、（Ｂ）いずれの形態で使用するかによって、研磨布を貼着する側の粘着剤層、及び研磨装置に貼着する側の粘着剤層は適宜選択することができる。
例えば、（Ａ）の形態で使用する場合には、補強シートを配置した側の面から遠い方の粘着剤層は、研磨布及び発泡体シートに貼着し得ることが必要であり、一方、補強シートを配置した側の面に近い方の粘着剤層は、補強シート及び研磨装置に貼着し得ることが必要である。これらの貼着特性は、発泡体シートの素材や表面状態、補強シートの素材や表面状態等を考慮して選択すればよい。
【００４３】
研磨布表面がスエード調の場合や、研磨布表面に不陸部が多く十分な接着面積を確保し難い場合には、両面粘着シートに研磨布を強固に接着させ難くなる。両面粘着シートに研磨布を強固に接着させる必要があるので、上記のような研磨布を用いる場合には、研磨布を貼着する側の粘着剤層の厚みを２０〜１５０μｍとして粘着力を向上させた両面粘着シートを用いることが好ましい。
また、研磨装置に貼着する側の粘着剤層は、剥がす際に粘着剤が残り難くなるようにするためには薄膜である方が有利であるので、厚みを５〜５０μｍとして再剥離性能を向上させることが好ましい。
【００４４】
また、粘着剤層は、貼着時及び研磨に使用する時の温度範囲において、ゴム状領域にあることが重要であり、ＪＩＳ Ｚ０２３７に規定する粘着テープ・粘着シート試験方法による１８０度引き剥がしの粘着力が５０ｍＮ／２５ｍｍ以上、室温における落下までの保持時間が６０分以上であることが好ましい。
更に研磨後に、研磨布を両面粘着シートから、又は研磨布ごと両面粘着シートを研磨装置から剥がす場合には、剥離し易いことが好ましい。すなわち、研磨の最中は強固に研磨布や研磨装置に付着し、その後は容易に剥離し得ることが好ましい。
【００４５】
このような粘着剤層の形成に用いられる粘着剤としては、アクリル系粘着剤、ウレタン系粘着剤、ゴム系粘着剤等が挙げられ、中でも粘着性能のバランスを確保し易いという点から、アクリル系粘着剤が更に好ましい。
【００４６】
以上、実施の形態を挙げて本発明を説明してきたが、本発明の両面粘着シートは、所望により、発泡体シートと補強シートとの間に接着剤層を設ける構成としていてもよい。
本発明において用い得る補強シート結合用接着剤層は、発泡体シートと補強シートとの間に位置し、両層を相互に固定するための層であり、その厚みは５〜１５０μｍであることが好ましい。
ところで、粘着剤は感圧性接着剤とも呼ばれ、広義の概念では接着剤に含まれるものであるが、本発明でいう「補強シート結合用接着剤」は、感圧性接着剤に限定されず、その他の接着剤、例えば、感熱性接着剤などを包含する任意の接着剤の意味である。前記の補強シート結合用接着剤としては、前記の粘着剤層用と同様のものを使用することができ、また接着剤としては水系、溶剤系を問わず、溶媒乾燥による一般タイプからドライラミタイプまで、３００ｍｍ／分による１８０度引き剥がし強度が５０ｍＮ／２５ｍｍ以上のものを使用することができる。
【００４７】
両面粘着シートを研磨布及び研磨装置に貼着するためには、上記したように粘着剤層を用い得るのに対し、発泡体シートと補強シートとを相互に固定するための補強シート用接着剤層としては、感圧性接着剤の他、感熱性接着剤などの任意の接着剤層も用いることができる。発泡体シートと補強シートとは、一旦相互に固定してしまえば剥離するという特別な要求はないので、補強シート用接着剤層を介して固定することができるのに対し、研磨装置側、及び研磨布側に位置する層には貼着後剥離するという要求もあるので、接着剤ではなく粘着剤で形成することが重要である。
【００４８】
また、本発明の両面粘着シートは、その粘着剤層面に剥離シートを積層した状態で供することができる。用いられ得る剥離シートには、両面を剥離処理した剥離シートと片面を剥離処理した剥離シートとがある。いずれの剥離シートも粘着剤層を被覆した後、粘着剤層と接する界面において容易に剥離シートを剥離し得ることが必要であり、かつ剥離シート上に粘着剤の残留がないことが要求される。ここでいう容易に剥離することが可能なレベルとは、一般的に１８０度引き剥がし粘着力が１Ｎ／２５ｍｍ未満のものをいう。
【００４９】
剥離シートとして具体的には、ポリエチレンテレフタレートや配向したポリプロピレン等の各種プラスチックフィルム、又は紙の上にシリコーン系あるいは非シリコーン系の剥離剤を塗工したものを用いることができる。粘着剤層の厚み精度を確保するために、プラスチックフィルムをベースとした剥離シートを用いることが望ましい。
【００５０】
本発明の両面粘着シートの種々の態様を添付図面に沿って説明する。
図１（模式的断面図）及び図２（模式的断面図）に示す本発明の両面粘着シート（１０）は、いずれも、発泡体シート（１）の両表面に粘着剤層（２），（２’）を有する態様であり、図１では、一方の粘着剤層（２）は露出しており、もう一方の粘着剤層（２’）上に両面剥離シート（４）を設けた状態を示す。
【００５１】
更に、図３（模式的断面図）、図４（模式的断面図）、及び図５（模式的断面図）に示す本発明の両面粘着シート（１０）は、前記の図１及び図２に示す態様に加え、いずれも、発泡体シート（１）と粘着剤層（２’）との間に補強シート（３）を有する態様であり、図３では、一方の粘着剤層（２）は露出しており、もう一方の粘着剤層（２’）上に両面剥離シート（４）を設けた状態を示す。また、図４では、逆に、一方の粘着剤層（２）上に両面剥離シート（４）を設け、もう一方の粘着剤層（２’）は露出した状態を示す。更に、図５では、両方の粘着剤層（２），（２’）上に、片面剥離シート（５），（５’）を設けた状態を示す。
【００５２】
図６（模式的断面図）、図７（模式的断面図）、及び図８（模式的断面図）に示す本発明の両面粘着シート（１０）は、いずれも、発泡体シート（１）と、粘着剤層（２’）との間に補強シート（３）とを有し、更に、発泡体シート（１）と補強シート（３）との間に補強シート用接着剤層（６）を有する態様である。また、図６では、一方の粘着剤層（２）は露出しており、もう一方の粘着剤層（２’）上に両面剥離シート（４）を設けた状態を示す。また、図７では、逆に、一方の粘着剤層（２）上に両面剥離シート（４）を設け、もう一方の粘着剤層（２’）は露出した状態を示す。更に、図８では、両方の粘着剤層（２），（２’）上に、片面剥離シート（５），（５’）を設けた状態を示す。
【００５３】
図１〜図８に示すように、前記剥離シートは、両面粘着シートと剥離シートの機能が損なわなければどのように配置しても構わない。従って、例えば、図１及び図２に示されるように、発泡体シート（１）及び粘着剤層（２），（２’）からなる両面粘着シートに剥離シートを設ける場合、両面剥離シート（４）もしくは片面剥離シート（５），（５’）を両面粘着シート（１０）の片面もしくは両面に配置する構成としてもよい。また、図３〜図５に示されるように、発泡体シート（１）、粘着剤層（２），（２’）、及び補強シート（３）からなる両面粘着シート（１０）に剥離シートを設ける場合も、両面剥離シート（４）もしくは片面剥離シート（５），（５’）を両面粘着シートの片面もしくは両面に配置する構成としてもよい。更に、図６〜図８に示されるように、発泡体シート（１）、粘着剤層（２），（２’）、補強シート（３）、及び補強シート用接着剤層（６）からなる両面粘着シート（１０）に剥離シートを設ける場合、両面剥離シート（４）もしくは片面剥離シート（５），（５’）を両面粘着シートの片面もしくは両面に配置する構成としてもよい。
【００５４】
本発明の両面粘着シートのうち、図１及び図２に示すように、発泡体シート（１）の両面側に粘着剤層（２），（２’）が設けられてなる両面粘着シート（１０）であって、補強シート（３）を有しない両面粘着シート（１０）は、例えば以下に示す方法（イ）〜方法（ハ）によって得ることができる。
方法（イ）
発泡体シート（１）の一方の面に粘着剤層（２’）を形成し、該粘着剤層（２’）の他方の面に両面剥離シート（４）を積層する。次いで、前記粘着剤層（２’）が接していない方の発泡体シート（１）の面に粘着剤層（２）を形成し、該粘着剤層（２）の他方の面と両面剥離シート（４）の他方の面（粘着剤層（２’）が接していない方の面）とが接するようにロール状に巻き取る。
【００５５】
方法（ロ）
発泡体シート（１）の両面にそれぞれ粘着剤層（２）、（２’）を同時に形成し、一方の粘着剤層（２’）側に両面剥離シート（４）を積層しつつ、該粘着剤層（２’）が接していない方の両面剥離シート（４）と他の粘着剤層（２）とが接するように巻き取る。
【００５６】
方法（ハ）
片面剥離シート（５）の剥離処理面に粘着剤層（２）を形成し、該粘着剤層（２）の他方の面に発泡体シート（１）を積層し、発泡体シート（１）の他方の面に粘着剤層（２’）を形成し、該粘着剤層（２’）の他方の面に片面剥離シート（５’）の剥離処理面を積層する。
【００５７】
前記の図６〜図８に示したように、補強シート（３）を有する両面粘着シート（１０）は、例えば以下に示す方法（ニ）〜方法（ヘ）によって得ることができる。
方法（ニ）
補強シート（３）の一方の面に粘着剤層（２’）を形成し、該粘着剤層（２’）の他方の面に両面剥離シート（４）を積層する。次いで、前記粘着剤層（２’）が接していない方の補強シート（３）の面に補強シート用接着剤層（６）を形成し、該補強シート用接着剤層（６）の他方の面に発泡体シート（１）を積層する。次いで、該発泡体シート（１）の他方の面に粘着剤層（２）を形成し、該粘着剤層（２）の他方の面と両面剥離シート（４）の他方の面（粘着剤層（２’）が接していない方の面）とが接するようにロール状に巻き取る。
方法（ホ）
補強シート（３）の一方の面に粘着剤層（２’）を形成し、該粘着剤層（２’）の他方の面に片面剥離シート（５’）の剥離処理面を積層する。次いで、前記粘着剤層（２’）が接していない方の補強シート（３）の面に補強シート用接着剤層（６）を形成し、該補強シート用接着剤層（６）の他方の面に発泡体シート（１）を積層する。次いで、該発泡体シート（１）の他方の面に粘着剤層（２）を形成し、該粘着剤層（２）の他方の面に片面剥離シート（５）の剥離処理面を積層する。
方法（ヘ）
片面剥離シート（５）の剥離処理面に粘着剤層（２）を形成し、該粘着剤層（２）の他方の面に発泡体シート（１）を積層し、発泡体シート（１）の他方の面に補強シート用接着剤層（６）を積層し、次いで該補強シート用接着剤層（６）の他方の面に補強シート（３）を積層し、該補強シート（３）の他方の面に粘着剤層（２’）を形成し、該粘着剤層（２’）の他方の面に片面剥離シート（５’）の剥離処理面を積層する。
【００５８】
剥離シート（４），（５），（５’）、発泡体シート（１）もしくは補強シート（３）上に各粘着剤及び補強シート用接着剤を塗工する方法としては、例えばコンマコーター、ダイコーター、リップコーター、キスコーター、グラビアコーター等を使用して行うことができる。コンマコーターを用いる場合、粘着剤や補強シート用接着剤の粘度は０．１〜１００Ｐａ・ｓ程度が良好である。
【００５９】
本発明の両面粘着シートは、それ全体として、１ｍ^２内の最大厚みと最小厚みとの差が１００μｍよりも大きいと、被研磨体を一定の均一な厚みに研磨することが困難となる。すなわち、圧力を掛けて研磨する際に厚みの厚い部分と薄い部分で圧力差が生じるからである。このため、研磨精度を必要とする場合は、両面粘着シートの１ｍ^２内の最大厚みと最小厚みとの差は、８０μｍ以内であることが好ましく、６０μｍ以内であることがより好ましい。
また、本発明による両面粘着シートの１ｍ^２内の平均厚さは、それ全体として、研磨する際に圧力を掛けたときに所望する２５％圧縮硬さを得ることと、両面粘着シートに対する水平方向の剪断力によって引き起こされるずり変形に抗するため４００μｍ〜２．５ｍｍであることが好ましい。尚、上記ずり変形は研磨特性を劣化させる。
両面粘着シートの厚さの測定は、プローブ直径１０ｍｍ、印加荷重５０ｇ／ｃｍ^２において、１μｍ桁表示が可能なデジタル計測器により行われ得る。
【００６０】
本発明による両面粘着シートの２５％圧縮硬さは、それ全体として、０．１〜１．３ＭＰａであることが重要であり、０．１５〜０．７ＭＰａであることが好ましい。両面粘着シート２５％圧縮硬さが発泡体シートの２５％圧縮硬さよりも硬くなるのは、次の理由による。両面粘着シートを構成する層は、発泡体層と各々厚さを有する粘着剤層、補強シート層からなり、両面粘着シートを２５％圧縮させると、発泡体の圧縮変形が他の層より早いため発泡体が２５％以上圧縮されるためである。
ここでいう「両面粘着シートの２５％圧縮硬さ」は、「発泡体シートの２５％圧縮硬さ」と同様、両面粘着シートをＪＩＳ Ｋ ６４００に記載される試験の一般的条件、すなわち温度２３℃、相対湿度５０％の環境に２４時間以上静置した後、該両面粘着シートを３０ｍｍ×３０ｍｍに打ち抜き、約１０ｍｍの厚さとなるようにシートを重ね合わせ、同温湿度環境下にて前記重ね合わせたシート全面を５０ｍｍ／分の速度で平行に圧縮し、元の厚みから２５％圧縮させた際の応力をいう。
両面粘着シートの２５％圧縮硬さが、０．１ＭＰａ未満だと両面粘着シートが柔軟になりすぎるので、被研磨体の局所の微細な段差を簡単に消去し得るが、「うねり」を消去できない。一方、１．３ＭＰａを越えると両面粘着シートが硬くなりすぎるので、局所の微細な段差及び「うねり」を消去するには長時間を要する。
【００６１】
以上、両面粘着シートについて説明してきたが、本発明の別の態様として前記の両面粘着シートに研磨布が積層された研磨布積層体が提供される。研磨布としては、特に限定されることなく従来公知の研磨布を用いることができる。好ましくは前記研磨布としては、合成皮革スエード又はベロア、硬質ウレタン発泡体等を用いることができる。
この場合、前記研磨布は両面粘着シートに予め設けるように構成しても使用時に両面粘着シートに設ける構成としても構わない。
【００６２】
【実施例】
以下、実施例によって本発明を具体的に説明するが、これらは本発明の範囲を限定するものではない。以下の実施例及び比較例において、部及び％は、特に断らない限り、重量による。
【００６３】
【作成例１】
分子量３０００のポリエチレングリコール１００部、１，４−ブタンジオール５部、触媒としてのアミン触媒（ＤＡＢＣＯ）０．５部、整泡剤としてのシリコーン整泡剤（ＫＦ６００２；信越化学工業社製）２．５部、発泡剤としての水０．１部、及びイソシアネートとしてのＭＤＩの４０部を混合撹拌し、剥離ライナー上にコーティングして発泡させつつ、１００℃にて１５分間加熱を行い、圧縮応力減衰率が５．１％、圧縮応力減衰率差が１．１％、１ｍ^２内の平均厚さが１２５２μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３０μｍのポリエーテル型軟質ポリウレタン発泡体シート（１−１）を得た。
【００６４】
【作成例２】
分子量３０００のポリオキシプロピレントリオール１００部、１，４−ブタンジオール１０部、触媒としてのアミン触媒（ＤＡＢＣＯ）０．５部、整泡剤としてのシリコーン整泡剤（ＫＦ６００２；信越化学工業社製）２．５部、発泡剤としての水０．１部、及びイソシアネートとしてのＭＤＩの４０部を混合撹拌し、剥離ライナー上にコーティングして発泡させつつ、１００℃にて１５分間加熱を行い、圧縮応力減衰率が８．６％、圧縮応力減衰率差が１．４％、１ｍ^２内の平均厚さが１２４８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が５５μｍのポリエステル型軟質ポリウレタン発泡体シート（１−２）を得た。
【００６５】
【作成例３】
分子量３０００のポリオキシプロピレントリオールの使用量を１００部とし、そして１，４−ブタンジオールの使用量を５部としたこと以外は作成例２と同様にして、圧縮応力減衰率が７．３％、圧縮応力減衰率差が１．３％、１ｍ^２内の平均厚さが１３３８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が１５５μｍのポリエステル型軟質ポリウレタン発泡体シート（１−３）を得た。
【００６６】
【作成例４】
分子量３０００のポリエチレングリコールの使用量を１００部とし、そして３−メチル−１，６−ヘキサンジオールの使用量を５部としたこと以外は作成例１と同様にして、圧縮応力減衰率が５．３％、圧縮応力減衰率差が１．１％、１ｍ^２内の平均厚さが１２０２μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３０μｍのポリエーテル型軟質ポリウレタン発泡体シート（１−５）を得た。
【００６７】
【作成例５】
分子量３０００のポリオキシプロピレントリオールの使用量を１００部とし、そして１，４−ブタンジオールの使用量を８部としたこと以外は作成例２と同様にして、圧縮応力減衰率が８．４％、圧縮応力減衰率差が１．３％、１ｍ^２内の平均厚さが１３０８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が５１μｍのポリエステル型軟質ポリウレタン発泡体シート（１−６）を得た。
【００６８】
【作成例６】
分子量３０００のポリオキシプロピレントリオール１００部、１，４−ブタンジオール６部、触媒としての錫触媒（ＤＢＴＤＬ）０．２部、整泡剤としてのシリコーン整泡剤（Ｆ−３０４；信越化学工業社製）１．５部、発泡剤としての水０．１部、及びＭＤＩ４０部を混合撹拌し、剥離ライナー上にコーティングして発泡させつつ、１００℃にて１５分間加熱を行い、圧縮応力減衰率が８．３％、圧縮応力減衰率差が１．３％、１ｍ^２内の平均厚さが１１９８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が１５５μｍのポリエステル型軟質ポリウレタン発泡体シート（１−７）を得た。
【００６９】
【実施例１】
本実施例では、図６に示すように、剥離シート（４）／粘着剤層（２’）／補強シート（３）／補強シート用接着剤層（６）／発泡体シート（１）／粘着剤層（２）からなる態様の両面剥離シート（４）に担持された両面粘着シート（１０）を調製した。
すなわち、最初に、粘着性アクリル樹脂を含む粘着剤〔東洋インキ製造（株）製〕１００部とイソシアネート誘導体系硬化剤〔東洋インキ製造（株）製〕３部とを攪拌混合した粘着剤組成物塗液をコンマコーターで乾燥膜厚３０μｍとなるように、補強シート（３）となるポリエチレンテレフタレートフィルム（厚さ＝７５μｍ）の全面に塗布し、粘着剤層（２’）を形成しつつ、巻き取り時に両面剥離処理してなるポリエチレンテレフタレート剥離シート（４）を該粘着剤層（２’）に０．３ＭＰａの圧力でラミネートして、剥離シート（４）／粘着剤層（２’）／補強シート層（３）からなる粘着シート（Ｃ）を得た。
【００７０】
次に、粘着シート（Ｃ）の補強シート（３）側に、前記と同様の粘着剤組成物塗液を同様の方法で同様の乾燥膜厚となるように全面塗布し、補強シート用接着剤層（６）を形成しつつ、巻き取り時に該補強シート用接着剤層（６）に作成例１で製造したポリウレタン発泡体シート（１−１）を０．３ＭＰａの圧力でラミネートして、剥離シート（４）／粘着剤層（２’）／補強シート層（３）／補強シート用接着剤層（６）／発泡体シート（１−１）からなる粘着シート（Ｂ）を得た。
【００７１】
最後に、ポリエチレンテレフタレート剥離シートを工程フィルムとして、前記と同様の粘着剤組成物塗液を同様の方法で同様の乾燥膜厚となるように全面塗布し、粘着剤層（２）を形成しつつ、巻き取り時に該粘着剤層（２）に前記粘着シート（Ｂ）の発泡体シート（１−１）側を０．３ＭＰａの圧力でラミネートした後、工程フィルムをはがし取り、図６に示すような剥離シート（４）／粘着剤層（２’）／補強シート（３）／補強シート用接着剤層（６）／発泡体シート（１−１）／粘着剤層（２）からなり、粘着剤層（２’）側の圧縮応力減衰率が５．４％、圧縮応力減衰率差が１．２％、１ｍ^２内の平均厚さが１４１７μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３１μｍの粘着シート（Ａ−１）を得た。
【００７２】
【実施例２】
実施例１で用いた発泡体シート（１−１）の代わりに、作成例２で製造したウレタン樹脂発泡体シート（１−２）を用いたこと以外は実施例１と同様にして、図６に示すように、剥離シート（４）／粘着剤層（２’）／補強シート（３）／補強シート用接着剤層（６）／発泡体シート（１−２）／粘着剤層（２）からなり、粘着剤層（２’）側の圧縮応力減衰率が８．９％、圧縮応力減衰率差が１．５％、１ｍ^２内の平均厚さが１４１３μｍ、１ｍ^２内の最大厚みと最小厚みとの差が５６μｍとなる粘着シート（Ａ−２）を得た。
【００７３】
【比較例１】
実施例１で用いた発泡体シート（１−１）の代わりに、作成例３で製造したウレタン樹脂発泡体シート（１−３）を用いたこと以外は実施例１と同様にして、図６に示すように、剥離シート（４）／粘着剤層（２’）／補強シート（３）／補強シート用接着剤層（６）／発泡体シート（１−３）／粘着剤層（２）からなり、粘着剤層（２’）側の圧縮応力減衰率が７．５％、圧縮応力減衰率差が１．３％、１ｍ^２内の平均厚さが１５０３μｍ、１ｍ^２内の最大厚みと最小厚みとの差が１５７μｍとなる粘着シート（Ａ−３）を得た。
【００７４】
【比較例２】
実施例１で用いた発泡体シート（１−１）の代わりに、圧縮応力減衰率が２４．３％、圧縮応力減衰率差が３．５％、１ｍ^２内の平均厚さが１２２８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が４１μｍのウレタン樹脂発泡体シート（１−４）を用いたこと以外は実施例１と同様にして、図６に示すように、剥離シート（４）／粘着剤層（２’）／補強シート（３）／補強シート用接着剤層（６）／発泡体シート（１−４）／粘着剤層（２）からなり、粘着剤層（２’）側の圧縮応力減衰率が２５．５％、圧縮応力減衰率差が３．７％、１ｍ^２内の平均厚さが１３９３μｍ、１ｍ^２内の最大厚みと最小厚みとの差が４２μｍとなる粘着シート（Ａ−４）を得た。
【００７５】
【実施例３】
本実施例では、図１に示すように、剥離シート（４）／粘着剤層（２’）／発泡体シート（１）／粘着剤層（２）からなる態様の両面剥離シート（４）に担持された両面粘着シート（１０）を調製した。
すなわち、最初に、粘着性アクリル樹脂を含む粘着剤〔東洋インキ製造（株）製〕１００部とイソシアネート誘導体系硬化剤〔東洋インキ製造（株）製〕３部とを攪拌混合した粘着剤組成物塗液を、コンマコーターで乾燥膜厚３０μｍとなるように、両面剥離処理してなるポリエチレンテレフタレート剥離シート（４）の全面に塗布し、粘着剤層（２’）を形成しつつ、巻き取り時に該粘着剤層（２’）に作成例４で製造した軟質ポリウレタン発泡体シート（１−５）を０．３ＭＰａの圧力でラミネートして、剥離シート（４）／粘着剤層（２’）／発泡体シート（１−５）からなる粘着シート（Ｄ）を得た。
【００７６】
次に、ポリエチレンテレフタレート剥離シートを工程フィルムとして前記と同様の粘着剤組成物塗液を同様の方法で同様の乾燥膜厚となるように全面塗布し、粘着剤層（２）を形成しつつ、巻き取り時に該粘着剤層（２）に前記粘着シート（Ｄ）の発泡体シート（１−５）側を０．３ＭＰａの圧力でラミネートした後、工程フィルムをはがし取り、図１に示すような剥離シート（４）／粘着剤層（２’）／発泡体シート（１−５）／粘着剤層（２）からなり、１ｍ^２内の平均厚さが１２６３μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３１μｍ、圧縮応力減衰率が５．３％、圧縮応力減衰率差が１．２％の粘着シート（Ｅ−１）を得た。
【００７７】
【実施例４】
実施例３で用いた発泡体シート（１−５）の代わりに、作成例５で製造したウレタン樹脂発泡体シート（１−６）を用いたこと以外は実施例３と同様にして、図１に示すように、剥離シート（４）／粘着剤層（２’）／発泡体シート（１−６）／粘着剤層（２）からなり、粘着剤層（２’）側の圧縮応力減衰率が８．５％、圧縮応力減衰率差が１．３％、１ｍ^２内の平均厚さが１３６８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が５２μｍとなる粘着シート（Ｅ−２）を得た。
【００７８】
【比較例３】
実施例３で用いた発泡体シート（１−５）の代わりに、作成例６で製造したウレタン樹脂発泡体シート（１−７）を用いたこと以外は実施例３と同様にして、図１に示すように、剥離シート（４）／粘着剤層（２’）／発泡体シート（１−７）／粘着剤層（２）からなり、粘着剤層（２’）側の圧縮応力減衰率が８．４％、圧縮応力減衰率差が１．３％、１ｍ^２内の平均厚さが１２５９μｍ、１ｍ^２内の最大厚みと最小厚みとの差が１５７μｍとなる粘着シート（Ｅ−３）を得た。
【００７９】
【比較例４】
実施例３で用いた発泡体シート（１−５）の代わりに、圧縮応力減衰率が２４．８％、圧縮応力減衰率差が３．５％、１ｍ^２内の平均厚さが１２５８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が５１μｍのウレタン樹脂発泡体シート（１−８）を用いたこと以外は実施例３と同様にして、図１に示すように、剥離シート（４）／粘着剤層（２’）／発泡体シート（１−８）／粘着剤層（２）からなり、粘着剤層（２’）側の圧縮応力減衰率が２５．０％、圧縮応力減衰率差が３．５％、１ｍ^２内の平均厚さが１３１９μｍ、１ｍ^２内の最大厚みと最小厚みとの差が５２μｍとなる粘着シート（Ｅ−４）を得た。
【００８０】
【研磨試験】
（１）研磨操作
実施例及び比較例で得られた粘着シート（５０ｍｍ×３００ｍｍ）の粘着剤層（２）側にＪＩＳ Ｒ６２５３に規定する１０００番の耐水研摩紙を貼りあわせ、もう一方の粘着剤層（２’）側の剥離シート（４）を剥がしてから、粘着剤層（２’）を研磨装置（テスター産業社製）の定盤側に貼着した。
他方、前記研磨装置に、下記被研磨試料が前記耐水研摩紙と並行な位置に対向するように被研磨試料を装着し、前記耐水研磨紙と下記被研磨試料とを接触せしめ、荷重０．０２ＭＰａの圧力が掛かるようにし、純水を２０ｍＬ／分の流量で供給しながら、２０ｍ／分の速度で、１０分間研磨作業を行った。
【００８１】
（２）繰り返し条件
上記した１０分間の研磨作業を１０回連続して行った後、耐水研摩紙のみを交換して更に１０分間の研磨作業を１０回連続して行う作業を行った。１０回毎に耐水研摩紙を交換し、合計で１００回、１０００分間の研磨作業を行った。
【００８２】
（３）被研磨試料
直径３０．０ｍｍの円形で平均厚さ０．１３０ｍｍ、一方の面の６０度反射光沢度が１４．７のポリカーボネートのシート（ａ）を、厚さ０．０３０ｍｍの粘着剤層を介して、直径３０．０ｍｍの円柱状圧子に貼付し被研磨試料とした。
厚さ測定は、プローブ直径１０ｍｍ、印加荷重５０ｇ／ｃｍ^２において、１μｍ桁表示が可能なデジタル計測器により実施した。
【００８３】
（４）評価方法
被研磨試料のポリカーボネートシート（ａ）の厚さを１３箇所、研磨の前後でそれぞれ測定し、ばらつき度合いの少ないものを「○」、ばらつき度合いの大きいものを「×」、○と×の中間を「△」のように３段階で評価した。
【００８４】
（５）結果
結果を表１に示す。両面粘着シートの最大最小厚み差が大きいと研磨量にばらつきが生じる。最大最小厚み差が小さくても圧縮応力減衰率が高いと良好な研磨は達成し得ず、更に圧縮応力減衰率差が大きいと膨潤変形が進行し、研磨量にばらつきが生じる。
【００８５】
【表１】

【００８６】
【発明の効果】
本発明の両面粘着シートを用いて研磨布を研磨装置に貼着し、被研磨体を研磨すると、研磨中に研磨スラリーによる膨潤変形を生じることなく、ウェーハ全面を均一に高低差を緩和するように研磨することができる。
【図面の簡単な説明】
【図１】発泡体シートと、その両表面の粘着剤層とからなる本発明の両面粘着シートに、その一方の粘着剤層において両面剥離シートを設けた状態を模式的に示す断面図である。
【図２】発泡体シートと、その両表面の粘着剤層とからなる本発明の両面粘着シートに、その両方の粘着剤層において片面剥離シートを設けた状態を模式的に示す断面図である。
【図３】発泡体シートと、その片側表面上の粘着剤層と、もう一方の表面上の補強シートと、その補強シート上の粘着剤層とからなる本発明の両面粘着シートに、その補強シート側粘着剤層において両面剥離シートを設けた状態を模式的に示す断面図である。
【図４】発泡体シートと、その片側表面上の粘着剤層と、もう一方の表面上の補強シートと、その補強シート上の粘着剤層とからなる本発明の両面粘着シートに、その補強シート側粘着剤層とは反対側の粘着剤層において両面剥離シートを設けた状態を模式的に示す断面図である。
【図５】発泡体シートと、その片側表面上の粘着剤層と、もう一方の表面上の補強シートと、その補強シート上の粘着剤層とからなる本発明の両面粘着シートに、その両方の粘着剤層において片面剥離シートを設けた状態を模式的に示す断面図である。
【図６】発泡体シートと、その片側表面上の粘着剤層と、もう一方の表面上の補強シート用接着剤層と、その補強シート用接着剤層上の補強シートと、その補強シート上の粘着剤層とからなる本発明の両面粘着シートに、その補強シート側粘着剤層において両面剥離シートを設けた状態を模式的に示す断面図である。
【図７】発泡体シートと、その片側表面上の粘着剤層と、もう一方の表面上の補強シート用接着剤層と、その補強シート用接着剤層上の補強シートと、その補強シート上の粘着剤層とからなる本発明の両面粘着シートに、その補強シート側粘着剤層とは反対側の粘着剤層において両面剥離シートを設けた状態を模式的に示す断面図である。
【図８】発泡体シートと、その片側表面上の粘着剤層と、もう一方の表面上の補強シート用接着剤層と、その補強シート用接着剤層上の補強シートと、その補強シート上の粘着剤層とからなる本発明の両面粘着シートに、その両方の粘着剤層において片面剥離シートを設けた状態を模式的に示す断面図である。
【図９】研磨装置の定盤側に貼着した研摩紙により、半導体ウェーハ表面をＣＭＰ技術により研磨する状態を模式的に示す平面図である。
【符号の説明】
１・・・発泡体シート；２，２’・・・粘着剤層；３・・・補強シート；
４・・・両面剥離シート；５，５’・・・片面剥離シート；
６・・・補強シート用接着剤層；１０・・・両面粘着シート；
１１・・・研磨パッド；１２・・・ウェーハ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a double-sided pressure-sensitive adhesive sheet and a polishing cloth laminate, more particularly to a double-sided pressure-sensitive adhesive sheet and a polishing cloth laminate used for attaching a polishing cloth to a polishing apparatus, and more particularly to an interlayer insulating film of a semiconductor device. A double-sided pressure-sensitive adhesive sheet, a polishing cloth and a double-sided pressure-sensitive adhesive sheet used as a fixing and cushioning material for a polishing cloth adapted for a flattening or metal wiring forming step (mainly chemical mechanical polishing; hereinafter referred to as CMP). The present invention relates to a laminate of the above.
[0002]
[Prior art]
In recent years, in order to reflect a circuit pattern of a semiconductor device on a semiconductor wafer, a mainstream method is to apply a photoresist resin to the semiconductor wafer, bake the resist resin using a photomask, and form a circuit pattern through an etching process. However, as the integration technology for increasing the speed and volume of the device has been advanced, it has been desired that the circuit wiring pattern can be stably drawn as fine as 0.13 μm or less. ing.
[0003]
However, there is a gradual thickness variation called "undulation" on the entire surface of the semiconductor wafer, that is, an altitude difference, and the altitude difference may be 2 to 4 μm or more. This undulation is small and desirably small. However, at the industrial level, elimination of the undulation is not satisfactory at present on the balance between productivity and cost. Further, due to the circuit pattern, there is a possibility that a step having a thickness of about 1 μm or less but having a different thickness may be locally generated. The presence of these undulations and stepped portions causes defocusing and blurring when forming a circuit pattern using a photomask, and the circuit pattern is not accurately reflected, causing a disconnection or short circuit of a semiconductor device circuit, resulting in extremely poor reliability. Let me do it.
[0004]
CMP has been proposed as a solution to this problem. In the CMP technique, a polishing cloth having a two-layer structure has been proposed in order to maintain a constant film thickness distribution and remove minute irregularities on the film surface (for example, see Non-Patent Document 1). In this two-layer polishing cloth, the lower layer is made of rubber elastic material to eliminate non-uniformity of the polishing allowance due to the warpage or undulation of the semiconductor wafer itself, and the surface layer is relatively fine irregularities on the surface generated in the semiconductor device process. A hard cloth is used to remove and flatten.
[0005]
Generally, a polyurethane-impregnated nonwoven fabric is used as a lower layer rubber elastic body used in a polishing pad having a two-layer structure as proposed in Non-Patent Document 1 described above. However, since the material has voids in the layer, stress relaxation remarkably occurs at the time of compression, which causes an unstable pressure state of the wafer during polishing. That is, as shown in FIGS. 9A and 9B, when the surface of the wafer (12) is polished with the polishing pad (11), the polishing pad (11) is rotated by the arrow C with the center C as the center of rotation. The wafer (12) is pressed against the rotating polishing pad (11) while rotating in the direction of (1) to perform polishing. Since the wafer (12) only rotates and does not move, as shown in FIG. 9 (a), a certain point A of the polishing pad (11) is moved at the point shown in FIG. 9 (a). Then, contact is started, and the state changes from the released state, which has not received the compressive force, to the compressed state, which receives the compressive force. Subsequently, the point A of the polishing pad (11) also rotates in the direction of the arrow R with the rotation of the polishing pad (11) in the direction of the arrow R, and receives a compressive force from the wafer (12) during that time. Subsequently, it reaches the point A shown in FIG. 9B in the compressed state, and thereafter is released from the compressive force from the wafer (12) to be in the released state.
[0006]
Here, when the entire region in the compressed state of the polishing pad (11) that is in contact with the wafer (12) is considered at a certain point in time, the entire region in the compressed state is at a point where the compression period is different. It is a set. Therefore, if the compressive stress of the polishing pad (11) changes with time or compression relaxation occurs, the state of contact with the surface of the wafer (12) changes and becomes unstable, which affects the polishing characteristics. become. In polishing by CMP, polishing having excellent non-uniformity may be required. If stress relaxation occurs during a period in which the polishing pad (11) is compressed by the wafer (12), the wafer may be polished. The compressive stress value differs in the plane where (12) is in contact, resulting in a poorly polished surface in terms of this non-uniformity. A specific defect is a phenomenon called "edge first", which is a state in which polishing of the peripheral portion of the wafer progresses too much more than inside.
[0007]
Furthermore, since the rubber elastic body of the lower layer used in the two-layer polishing pad has air permeability, it absorbs and swells the slurry water used at the time of polishing, and partially or entirely setstle. And the rubber elasticity changes (hereinafter, these phenomena are collectively referred to as “swelling deformation”). If swelling deformation progresses during polishing, it is not possible to meet the demand for uniform polishing or precision polishing.
Therefore, the two-layer polishing pad is immersed in the polishing slurry for a long time before polishing to cause swelling deformation of the polyurethane-impregnated nonwoven fabric, so that swelling deformation does not occur during subsequent polishing. Was.
[0008]
As a solution to this swelling deformation, it has been proposed to provide a waterproof material layer between the surface hard material and the lower polyurethane impregnated nonwoven fabric (for example, JP-A-11-156701: Patent Document 1). However, the infiltration of the slurry from the side surface of the polishing cloth laminate could not be prevented, and was incomplete.
[0009]
[Non-patent document 1]
Junji Watanabe et al., Pad Configuration in Surface Reference Polishing, Proc. 183
[Patent Document 1]
JP-A-11-156701
[0010]
[Problems to be solved by the invention]
The present invention is capable of uniformly polishing the entire surface of the wafer along the undulations and steps, even in semiconductor wafers having undulations and wafers having local minute steps in the circuit formation process. An object of the present invention is to provide an adhesive tape fixed to a polishing cloth. More specifically, a polishing cloth laminate that does not cause significant stress relaxation, does not need to immerse the polishing cloth laminate in the polishing slurry for a long time before polishing, and does not cause swelling deformation due to the polishing slurry during polishing. It is an object of the present invention to provide a polishing cloth-fixed pressure-sensitive adhesive tape capable of forming the following.
[0011]
[Means for Solving the Problems]
The present inventors have conducted intensive studies in view of the above problems, and by using a double-sided pressure-sensitive adhesive sheet having a specific thickness range and a specific compressive stress attenuation rate, without generating a fatal vibration in the polishing operation, They have found that a double-sided PSA sheet having good polishing properties can be provided, and have completed the present invention.
Thus, the present invention ² The difference between the maximum thickness and the minimum thickness is within 100 μm (ie, 0 or more and 100 μm or less), and the maximum value of the compression stress in the compression test for maintaining the compression distance after compression constant and the maximum value of the compression stress can be obtained. The double-sided pressure-sensitive adhesive sheet is characterized in that the compressive stress decay rate determined from the compressive stress value 0.1 seconds after the point of time is 15% or less (that is, 0 or more and 15% or less).
According to a preferred embodiment of the present invention, the double-sided pressure-sensitive adhesive sheet is 1 m ² The difference between the maximum thickness and the minimum thickness is within 100 μm, and the maximum value of the compressive stress in the compression test in which the compression distance after compression is kept constant, and 0.1 second from the time when the maximum value of the compressive stress is obtained The pressure-sensitive adhesive layer is formed on both surfaces of the foamed sheet having a compressive stress decay rate determined from the subsequent compressive stress value of 15% or less.
According to another preferred aspect of the present invention, in the compression test in which the foam sheet is repeatedly subjected to compression and release operations in water, the maximum value of the compression stress in the compression operation of maintaining a constant compression distance after the initial compression, Initial compressive stress decay rate obtained from the compressive stress value 0.1 second after the time when the maximum compressive stress value is obtained, the maximum compressive stress value by the same 10,000th compression / release operation, and its compressive stress The difference between the compression stress value 0.1 second after the time when the maximum value was obtained and the 10,000th compression stress decay rate obtained from the compression stress value is 2% or less.
In still another preferred embodiment of the present invention, a reinforcing sheet having a breaking strength of 40 MPa or more and 500 MPa or less is provided between any one of the pressure-sensitive adhesive layers and the foam sheet.
The present invention also relates to a polishing cloth laminate including a polishing cloth laminated on one of the double-sided pressure-sensitive adhesive sheet and the pressure-sensitive adhesive layer.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The details of the present invention will be described with reference to some preferred embodiments.
However, it goes without saying that the present invention is not limited to the following embodiments.
As described above, the double-sided pressure-sensitive adhesive sheet of the present invention has a width of 1 m. ² The difference between the maximum thickness and the minimum thickness is within 100 μm, and the compressive stress decay rate is 15% or less. In a preferred embodiment of the present invention, 1 m ² A double-sided pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is provided on each of both surfaces of a flexible urethane foam sheet having a difference between the maximum thickness and the minimum thickness within 100 μm and a compressive stress attenuation rate of 15% or less. . Here, the double-sided pressure-sensitive adhesive sheet is also called a double-sided pressure-sensitive adhesive tape or double-sided pressure-sensitive adhesive film.
Further, in the double-sided pressure-sensitive adhesive sheet of the present invention, a reinforcing sheet having a breaking strength of 40 MPa or more may be provided between the foam sheet and one pressure-sensitive adhesive layer.
[0013]
The foam sheet suitably used in the double-sided pressure-sensitive adhesive sheet of the present invention is 1 m ² The difference between the maximum thickness and the minimum thickness is 0 or more and 100 μm or less. 1m of foam sheet ² The difference between the maximum thickness and the minimum thickness is most preferably 0, but practically there is an allowable range. If it is larger than 100 μm, it becomes difficult to polish the object to be polished to a uniform thickness. That is, a pressure difference occurs between a thick portion and a thin portion when polishing by applying pressure. For this reason, when polishing accuracy is required, 1 m ² The difference between the maximum thickness and the minimum thickness is preferably 0 or more and 100 μm or less, more preferably 80 μm or less, and even more preferably 60 μm or less.
[0014]
Also, 1m of foam sheet ² The average thickness is preferably within a range of 150 μm to 2.4 mm in order to resist shear deformation that deteriorates polishing characteristics caused by a horizontal shear force applied to the double-sided pressure-sensitive adhesive sheet during polishing.
The thickness of the foam sheet was measured by using a probe having a diameter of 10 mm and an applied load of 50 g / cm. ² , A digital measuring instrument capable of displaying 1 μm digits.
[0015]
Further, the foam sheet preferably has a compressive stress attenuation rate of 0% to 15%, more preferably 0% to 10%.
The term “compression stress decay rate” as used in the present invention refers to a general condition of a test described in JIS K 6400, that is, after leaving a foam sheet for 24 hours or more in an environment of a temperature of 23 ° C. and a relative humidity of 50%, The foam sheet is punched into a sample sheet having a diameter of 22.6 mm, and a plurality of the sample sheets are stacked so as to have a total thickness of about 10 mm, and the entire sample sheet is stacked under the same temperature and humidity environment. Is compressed in parallel by an indenter at a speed of 200 mm / min until the compressive stress value becomes 0.1 MPa, and at the moment when the compressive stress value shows 0.1 MPa, the indenter is stopped, and the compression gap at that time is maintained. From the maximum value (a) of the compressive stress at that time (ie, 0.1 MPa) and the compressive stress value (b) 0.1 seconds after the time when the maximum value of the compressive stress was obtained, the following equation (A):
Compressive stress decay rate (%) = [(ab) / a] × 100 (A)
Can be calculated by
[0016]
The 10,000th cycle test for obtaining the compressive stress decay rate is performed by repeating the cycle consisting of the compression operation and the release operation for obtaining the “compressive stress decay rate” 10,000 times. The cycle is as follows.
B) The test piece is compressed to 0.1 MPa by moving the indenter toward the sample at a speed of 200 mm / min.
B) In that state, stop the indenter for one second while maintaining the compression distance.
C) Move the indenter at a speed of 200 mm / min in a direction away from the sample and release it until it shows 0.0 MPa.
D) With the compression force released from the sample, stop the indenter for 1 second.
When the cycle consisting of the operations a) to d) is repeated 10,000 times, the initial compression stress maximum value (a-1) and the initial compression The initial compressive stress value (b-1) 0.1 seconds after the time when the maximum stress value was obtained was measured, and further, at the time of the 10,000th compression operation a) and the stop operation b), 10,000 The maximum compressive stress value (am) and the 10,000th compressive stress value (b-m) 0.1 seconds after the time when the 10,000th compressive stress maximum value is obtained are measured. Further, the initial compressive stress decay rate (c-1) is calculated from the initial compressive stress maximum value (a-1) and the initial compressive stress value (b-1), and the 10,000th compressive stress maximum value (am) is calculated. ) And the 10,000th compressive stress value (b-m), the 10,000th compressive stress decay rate (cm) is calculated, and the difference therebetween is determined.
[0017]
In the measurement of compressive stress decay rate in water, the water surface and the top surface of the measurement sample were matched in a water tank whose bottom size was 100 mm x 100 mm, height was 50 mm, and the water temperature was controlled at 23 ± 0.5 ° C. Perform the test with a sufficient amount of water. A sample for measurement in a dry state is charged into the above-mentioned water tank, and the cycle consisting of the above-mentioned compression / release operation in distilled water is repeated.
[0018]
If the compressive stress decay rate of the foam sheet exceeds 15%, the pressure state of the wafer during polishing becomes unstable due to stress relaxation of the double-sided pressure-sensitive adhesive sheet, and good polishing uniformity cannot be achieved. On the other hand, if the difference between the compressive stress attenuation rate of the foam sheet for the first time and that for the 10,000th time exceeds 2%, the initially set polishing conditions cannot be reproduced, and good polishing uniformity cannot be achieved.
[0019]
Further, the foam sheet preferably has a 25% compression hardness of 0.1 to 1.0 MPa, more preferably 0.2 to 0.5 MPa.
The “25% compression hardness of the foam sheet” in the present invention means that the foam sheet is subjected to an environment described in the general conditions of the JISK 6400 test, that is, an environment of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. After standing for 24 hours or more, the foam sheet is punched into 30 mm × 30 mm, and a plurality of sample sheets are stacked so as to have a thickness of about 10 mm, and the sample is obtained under the same temperature and humidity environment as described above. This refers to the stress when the entire surface of the sheet is compressed in parallel at a speed of 50 mm / min and the original thickness is reduced by 25%.
[0020]
If the 25% compression hardness of the foam sheet is less than 0.1 MPa, the double-sided pressure-sensitive adhesive sheet becomes flexible and easily undergoes shear deformation, so that it becomes difficult to uniformly polish the surface film thickness over the entire surface of the object to be polished. is there. On the other hand, if the 25% compression hardness of the foam sheet exceeds 1.0 MPa, the double-sided pressure-sensitive adhesive sheet tends to be hard. Therefore, the portion having a high elevation without following fine steps and “undulations” on the surface of the object to be polished. Is preferentially polished, and it tends to be difficult to uniformly polish the surface film thickness over the entire surface of the object to be polished.
[0021]
Examples of the foam sheet used in the present invention include polyurethane, polyethylene, and silicone rubber, which can be obtained by various methods. Of these, polyurethane is preferable because the desired compression stress attenuation rate, hardness, and thickness accuracy are easily obtained.
[0022]
The polyurethane foam sheet used in the present invention will be described. In the polyurethane foam, a urethane skeleton is formed by the reaction between the polyol and the polyisocyanate, and the foam is formed by adding a foaming agent and a foam stabilizer in order to uniformly disperse and stabilize the foam in the reaction product. Is done.
[0023]
The polyol used in the present invention may be any of a polyester polyol and a polyether polyol generally used in the urethane industry, and is not particularly limited. However, the polyether polyol tends to show a better compressive stress decay rate. This is presumed to be because the ether bond exhibits a behavior closer to rubber elasticity.
Known polyether polyols can be used as the polyether polyol used in the present invention. For example, water, propylene glycol, ethylene glycol, glycerin, using a low molecular weight polyol such as trimethylolpropane as an initiator, ethylene oxide, propylene oxide, butylene oxide, polyether polyol obtained by polymerizing an oxirane compound such as tetrahydrofuran Specifically, those having two or more functional groups such as polypropylene glycol, polyethylene glycol and polytetramethylene glycol can be used. The molecular weight of the polyether polyol can be used from a low molecular weight to a high molecular weight, preferably a polyether polyol having a molecular weight of 1,000 to 5,000 and bifunctional or more, more preferably a molecular weight of 1,500 to 4,000. Is used.
[0024]
As the polyester polyol, for example, a known aliphatic polyester polyol can be used. Examples of the acid component include adipic acid, succinic acid, azelaic acid, sebacic acid, and dodecane diacid. Examples of the glycol component include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, and 1,6. -Hexane glycol, 2-methyl-1,3-propanediol, 1-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,6-hexanediol, 3- Methyl-1,6-hexanediol, 1-methyl-1,6-hexanediol, 4-methyl-1,7-heptanediol, 4-methyl-1,9-nonanediol, 2-methyl-1,9- Nonanediol, 3-methyl-1,9-nonanediol, 3,3′-dimethylolheptane, polyoxy Ethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, and polyol components include, for example, glycerin, trimethylolpropane, polyoxypropylene triol, and pentaerythritol. Other examples include aliphatic polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (β-methyl-γ-valerolactone), and polyvalerolactone. The molecular weight of the aliphatic polyester polyol can be used from a low molecular weight to a high molecular weight, preferably a 1,000 to 5,000 molecular weight bifunctional or more aliphatic polyester polyol, more preferably a molecular weight of 1,500 to 3, 500 bifunctional or more aliphatic polyester polyols are used.
[0025]
Examples of the polyisocyanate used in the present invention include an aromatic polyisocyanate, an aliphatic polyisocyanate, an araliphatic polyisocyanate, and an alicyclic polyisocyanate.
[0026]
Examples of the aromatic polyisocyanate include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6 -Tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, or 4,4 ' , 4 "-triphenylmethane triisocyanate.
[0027]
Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, Examples include 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and lysine triisocyanate.
[0028]
As the araliphatic polyisocyanate, for example, ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene And 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethyl xylylene diisocyanate.
[0029]
Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, and methyl-2. , 4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, etc. Can be mentioned. In addition, a trimethylolpropane adduct of the above polyisocyanate, a burette that has been reacted with water, a trimer having an isocyanurate ring, or the like can also be used in part. A reaction product of the above-mentioned polyhydric alcohol polyether adduct and diisocyanate can also be used as the polyisocyanate.
[0030]
Examples of the foaming agent used in the present invention include water, methylene chloride, nitrogen, air, and chlorofluorocarbon.
[0031]
As the foam stabilizer, various silicone oils can be used. However, since an oily substance such as bleed-out leads to contamination of the object to be polished, a reaction that reacts with the polyol, polyisocyanate, foaming agent, or the like is performed. Foam stabilizers having groups are preferred. Examples of such a reactive group include an OH group, an N (R) H group (where R is an alkyl group having 1 to 4 carbon atoms), NH ₂ Group, SH group, COOH group, Si-OCH ₃ Group (methoxy group). A typical silicone foam stabilizer is a polydimethylsiloxane-polyalkylene ether block copolymer represented by the following general formula (I).
[0032]
Embedded image

[0033]
In the general formula (I), m, n, and p are integers of 1 or more; ¹ And B are divalent organic groups; ² Is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, A is a reactive group, for example, an OH group, an N (R) H group (where R is an alkyl group having 1 to 4 carbon atoms) ), NH ₂ Group, SH group, COOH group, or Si-OCH ₃ Group (methoxy group). By using a reactive silicone foam stabilizer, the air permeability of the foam layer of the pressure-sensitive adhesive sheet according to the present invention is reduced, and as a result, water absorption is higher than when a normal additive (non-reactive) silicone foam stabilizer is used. Properties are greatly reduced, and stable polishing is possible. As other auxiliaries, conventional auxiliaries used in producing polyurethane can be used.
[0034]
As a method for producing a polyurethane foam using the above-mentioned polyol, polyisocyanate, foaming agent and reactive silicone foam stabilizer, and other auxiliaries, a water foaming method which is usually carried out, a volatile solvent Any method such as a foaming method and a method of bubbling air can be used. However, since the thermal conductivity is reduced by using a microcell, the former two methods are more cured than the latter gas bubbling method. -It is preferable because the time is shortened. As a method of adjusting the cell diameter of the obtained microcell urethane, for example, the number of added parts of the silicone foam stabilizer and the amount of the catalyst is increased, or the number of functional groups of the crosslinking agent is increased by changing the functional group of the polyol from trifunctional to bifunctional. The cell diameter can be reduced by increasing the pressure or increasing the pressure during foaming.
[0035]
Increasing the amount of the tin catalyst over the amine catalyst can also make the cell diameter smaller, but is not preferred in the present invention. However, an additive or an acid typified by an activator used for polishing or a metal contained in the object to be polished, an aqueous solution containing a base, or a metal contained in a lubricating oil may be contained. There are cases.
[0036]
The polyurethane foam can be formed into a sheet by a conventionally known general method. For example, JP-A-51-67396 and JP-A-53-6365 disclose an unfoamed composition capable of forming a polyurethane by reacting from an extrusion die onto a process film and foaming it. A method has been proposed in which the resin is cured while passing through an oven.
[0037]
When the process film is subjected to a peeling treatment, the process film is peeled after the sheet is formed, so that a urethane-only foam sheet can be obtained. Also, if the process film is not subjected to a peeling treatment, since polyurethane and the process film are firmly bonded in the process of foaming and curing of polyurethane, the process film can be used as a reinforcing sheet described later, Both sheets can be laminated without providing a special adhesive layer or pressure-sensitive adhesive layer between the foam sheet and the reinforcing sheet.
In the case of using a process film formed by a release treatment, the composition is developed and foamed and cured on the release treatment surface of one process film, or the above-described composition is formed between the release treatment surfaces of the two process films. There is a method of foaming and curing after sandwiching the composition, but the latter is preferred. That is, when a polyurethane foam sheet is formed using two process films, and the two process films are peeled off, a foam sheet having a smooth skin layer on both surfaces of the sheet is formed. When an adhesive layer or a pressure-sensitive adhesive layer is laminated on this skin layer, it is effective to improve the adhesion between the layers, and the thickness accuracy is easily controlled, so that two process films are preferably used.
[0038]
The process film used for forming the urethane foam sheet has a smoothness such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) and a heat resistance that does not melt and cut even at a temperature of about 100 ° C. for several minutes. Is used.
[0039]
Since the breaking strength of the above-described foam sheet is generally relatively low (for example, 5 MPa or less), by providing a reinforcing sheet having a breaking strength of 40 MPa or more between the foam sheet and one of the adhesive layers, double-sided adhesiveness is obtained. The strength of the sheet can be increased. If the breaking strength of the double-sided pressure-sensitive adhesive sheet can be increased, for example, after polishing, the double-sided pressure-sensitive adhesive sheet may be broken together with the polishing cloth, or after polishing, when the polishing cloth is peeled off from the double-sided pressure-sensitive adhesive sheet, the double-sided pressure-sensitive adhesive sheet may be damaged. And easy to peel off.
[0040]
The reinforcing sheet is preferably various plastic sheets, and polyethylene terephthalate is more preferable from the viewpoint of thickness accuracy, heat resistance, chemical resistance, and versatility.
The thickness is preferably from 12 to 250 μm, and more preferably from 25 to 100 μm.
[0041]
When the reinforcing sheet is provided, the laminated cross-sectional structure of the double-sided pressure-sensitive adhesive sheet is asymmetric as in the embodiments shown in FIGS. 3 to 8 described below, but the compressive stress decay rate when measured on at least one surface is 0. The compression stress attenuation rate of the pressure-sensitive adhesive layer surface remote from the side on which the reinforcing sheet is arranged is more preferably in the above range.
[0042]
The pressure-sensitive adhesive layer used in the present invention will be described.
The double-sided pressure-sensitive adhesive sheet of the present invention is located between, for example, a polishing cloth and a polishing apparatus by the CMP technique, and is used for attaching both. As shown in FIGS. 3 to 8, since the laminated cross-sectional configuration is asymmetric,
(A) attaching a polishing cloth to the pressure-sensitive adhesive layer remote from the surface on which the reinforcing sheet is disposed, and adhering a pressure-sensitive adhesive layer closer to the surface on the side where the reinforcing sheet is disposed to a polishing apparatus;
(B) An adhesive layer farther from the surface on which the reinforcing sheet is arranged is attached to the polishing device, and a polishing cloth is adhered on the adhesive layer closer to the surface on which the reinforcing sheet is arranged, etc. Although the form of (A) is considered, the form of (A) is preferable.
Depending on which form of (A) or (B) is used, the pressure-sensitive adhesive layer on the side to which the polishing cloth is adhered and the pressure-sensitive adhesive layer on the side to be bonded to the polishing apparatus can be appropriately selected.
For example, when used in the form of (A), the pressure-sensitive adhesive layer farther from the surface on which the reinforcing sheet is disposed needs to be able to be attached to the polishing cloth and the foam sheet. It is necessary that the pressure-sensitive adhesive layer closer to the surface on which the reinforcing sheet is arranged can be attached to the reinforcing sheet and the polishing device. These sticking characteristics may be selected in consideration of the material and surface state of the foam sheet, the material and surface state of the reinforcing sheet, and the like.
[0043]
When the surface of the polishing cloth is suede-like, or when the surface of the polishing cloth has many uneven portions and it is difficult to secure a sufficient bonding area, it becomes difficult to firmly adhere the polishing cloth to the double-sided pressure-sensitive adhesive sheet. Since it is necessary to firmly adhere the polishing cloth to the double-sided pressure-sensitive adhesive sheet, when the above-mentioned polishing cloth is used, the pressure-sensitive adhesive layer on the side where the polishing cloth is stuck is made to have a thickness of 20 to 150 μm to improve the adhesive strength. It is preferable to use a double-sided pressure-sensitive adhesive sheet that has been subjected to the heat treatment.
Further, the pressure-sensitive adhesive layer on the side to be adhered to the polishing apparatus is preferably a thin film in order to prevent the pressure-sensitive adhesive from remaining when peeled off. Preferably, it is improved.
[0044]
Further, it is important that the pressure-sensitive adhesive layer is in a rubber-like region in the temperature range at the time of sticking and when used for polishing, and the 180-degree peeling by the pressure-sensitive adhesive tape / pressure-sensitive sheet test method specified in JIS Z0237. It is preferable that the adhesive strength is 50 mN / 25 mm or more, and the holding time until dropping at room temperature is 60 minutes or more.
Further, when the polishing cloth is peeled off from the double-sided pressure-sensitive adhesive sheet after polishing or the double-sided pressure-sensitive adhesive sheet together with the polishing cloth from the polishing apparatus, it is preferable that the polishing cloth be easily peeled off. That is, it is preferable that the material can be firmly adhered to the polishing cloth or the polishing apparatus during polishing, and then easily peeled off.
[0045]
Examples of the pressure-sensitive adhesive used for forming such a pressure-sensitive adhesive layer include an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, and the like. Adhesives are more preferred.
[0046]
As described above, the present invention has been described with reference to the embodiments. However, the double-sided pressure-sensitive adhesive sheet of the present invention may have a configuration in which an adhesive layer is provided between a foam sheet and a reinforcing sheet, if desired.
The reinforcing sheet bonding adhesive layer that can be used in the present invention is located between the foam sheet and the reinforcing sheet, and is a layer for fixing both layers to each other, and the thickness thereof may be 5 to 150 μm. preferable.
By the way, the pressure-sensitive adhesive is also called a pressure-sensitive adhesive, and is included in the adhesive in a broad sense, but the “adhesive for reinforcing sheet bonding” in the present invention is not limited to the pressure-sensitive adhesive, Any adhesive, including other adhesives, such as heat-sensitive adhesives, is meant. As the adhesive for bonding the reinforcing sheet, the same adhesive as that for the pressure-sensitive adhesive layer can be used, and the adhesive may be a water-based adhesive or a solvent-based adhesive. Up to 180 mm peeling strength at 300 mm / min can be used up to 50 mN / 25 mm.
[0047]
In order to stick the double-sided pressure-sensitive adhesive sheet to the polishing cloth and the polishing apparatus, the pressure-sensitive adhesive layer can be used as described above, whereas the adhesive for the reinforcing sheet for fixing the foam sheet and the reinforcing sheet to each other is used. As the layer, an arbitrary adhesive layer such as a heat-sensitive adhesive can be used in addition to the pressure-sensitive adhesive. Since there is no special requirement that the foam sheet and the reinforcing sheet are peeled off once they are fixed to each other, the foam sheet and the reinforcing sheet can be fixed via the reinforcing sheet adhesive layer, while the polishing apparatus side, and Since there is a demand that the layer located on the side of the polishing cloth be peeled off after application, it is important to form the layer with an adhesive instead of an adhesive.
[0048]
The double-sided pressure-sensitive adhesive sheet of the present invention can be provided in a state where a release sheet is laminated on the surface of the pressure-sensitive adhesive layer. Release sheets that can be used include release sheets that have been subjected to release treatment on both sides and release sheets that have undergone release treatment on one side. After any release sheet has been coated with the pressure-sensitive adhesive layer, it is necessary that the release sheet can be easily peeled off at the interface in contact with the pressure-sensitive adhesive layer, and it is required that no adhesive remains on the release sheet. . The level at which the film can be easily peeled here means a film having a peeling force of less than 1 N / 25 mm in general.
[0049]
Specific examples of the release sheet include various plastic films such as polyethylene terephthalate and oriented polypropylene, and paper obtained by applying a silicone-based or non-silicone-based release agent on paper. In order to secure the thickness accuracy of the pressure-sensitive adhesive layer, it is desirable to use a release sheet based on a plastic film.
[0050]
Various embodiments of the double-sided pressure-sensitive adhesive sheet of the present invention will be described with reference to the accompanying drawings.
The double-sided pressure-sensitive adhesive sheet (10) of the present invention shown in FIG. 1 (schematic cross-sectional view) and FIG. 2 (schematic cross-sectional view) has a pressure-sensitive adhesive layer (2) on both surfaces of the foam sheet (1). In FIG. 1, one pressure-sensitive adhesive layer (2) is exposed, and a double-sided release sheet (4) is provided on the other pressure-sensitive adhesive layer (2 ′). Is shown.
[0051]
Further, the double-sided pressure-sensitive adhesive sheet (10) of the present invention shown in FIG. 3 (schematic cross-sectional view), FIG. 4 (schematic cross-sectional view), and FIG. In addition to the embodiments shown, each of the embodiments has a reinforcing sheet (3) between a foam sheet (1) and an adhesive layer (2 ′). In FIG. 3, one adhesive layer (2) is This shows a state in which the double-sided release sheet (4) is provided on the other pressure-sensitive adhesive layer (2 ') which is exposed. FIG. 4 shows a state in which a double-sided release sheet (4) is provided on one adhesive layer (2) and the other adhesive layer (2 ') is exposed. Further, FIG. 5 shows a state in which single-sided release sheets (5) and (5 ') are provided on both pressure-sensitive adhesive layers (2) and (2').
[0052]
The double-sided pressure-sensitive adhesive sheet (10) of the present invention shown in FIG. 6 (schematic cross-sectional view), FIG. 7 (schematic cross-sectional view), and FIG. 8 (schematic cross-sectional view) is the same as the foam sheet (1). And a pressure-sensitive adhesive layer (2 ′), a reinforcing sheet (3), and a reinforcing sheet adhesive layer (6) between the foam sheet (1) and the reinforcing sheet (3). It is an aspect to have. FIG. 6 shows a state in which one pressure-sensitive adhesive layer (2) is exposed and a double-sided release sheet (4) is provided on the other pressure-sensitive adhesive layer (2 ′). FIG. 7 shows a state in which a double-sided release sheet (4) is provided on one adhesive layer (2) and the other adhesive layer (2 ') is exposed. Further, FIG. 8 shows a state in which single-sided release sheets (5) and (5 ') are provided on both pressure-sensitive adhesive layers (2) and (2').
[0053]
As shown in FIGS. 1 to 8, the release sheet may be arranged in any manner as long as the functions of the double-sided pressure-sensitive adhesive sheet and the release sheet are not impaired. Therefore, for example, as shown in FIGS. 1 and 2, when a release sheet is provided on a double-sided pressure-sensitive adhesive sheet comprising a foam sheet (1) and pressure-sensitive adhesive layers (2) and (2 ′), a double-sided release sheet (4 ) Or the single-sided release sheets (5) and (5 ′) may be arranged on one or both sides of the double-sided pressure-sensitive adhesive sheet (10). As shown in FIGS. 3 to 5, a release sheet is placed on a double-sided pressure-sensitive adhesive sheet (10) including a foam sheet (1), pressure-sensitive adhesive layers (2) and (2 ′), and a reinforcing sheet (3). Also in the case of providing, the double-sided release sheet (4) or the single-sided release sheets (5) and (5 ') may be arranged on one side or both sides of the double-sided adhesive sheet. Further, as shown in FIG. 6 to FIG. 8, it is composed of a foam sheet (1), pressure-sensitive adhesive layers (2) and (2 ′), a reinforcing sheet (3), and a reinforcing sheet adhesive layer (6). When the release sheet is provided on the double-sided pressure-sensitive adhesive sheet (10), the double-sided release sheet (4) or the single-sided release sheets (5) and (5 ') may be arranged on one or both sides of the double-sided pressure-sensitive adhesive sheet.
[0054]
As shown in FIG. 1 and FIG. 2, the double-sided pressure-sensitive adhesive sheet (10) in which pressure-sensitive adhesive layers (2) and (2 ′) are provided on both sides of a foam sheet (1) is provided. ), And the double-sided pressure-sensitive adhesive sheet (10) having no reinforcing sheet (3) can be obtained, for example, by the following methods (a) to (c).
Method (a)
An adhesive layer (2 ') is formed on one surface of the foam sheet (1), and a double-sided release sheet (4) is laminated on the other surface of the adhesive layer (2'). Next, an adhesive layer (2) is formed on the surface of the foam sheet (1) that is not in contact with the adhesive layer (2 '), and the other surface of the adhesive layer (2) and the double-sided release sheet The film is wound into a roll so that the other surface of (4) (the surface to which the pressure-sensitive adhesive layer (2 ') is not in contact) is in contact.
[0055]
Method (b)
The pressure-sensitive adhesive layers (2) and (2 ′) are simultaneously formed on both surfaces of the foam sheet (1), and the double-sided release sheet (4) is laminated on one of the pressure-sensitive adhesive layers (2 ′). The double-sided release sheet (4), which is not in contact with the agent layer (2 '), is wound so that the other pressure-sensitive adhesive layer (2) is in contact.
[0056]
Method (c)
The pressure-sensitive adhesive layer (2) is formed on the release-treated surface of the single-sided release sheet (5), and the foam sheet (1) is laminated on the other surface of the pressure-sensitive adhesive layer (2). An adhesive layer (2 ') is formed on the other surface, and a release-treated surface of a single-sided release sheet (5') is laminated on the other surface of the adhesive layer (2 ').
[0057]
As shown in FIGS. 6 to 8, the double-sided pressure-sensitive adhesive sheet (10) having the reinforcing sheet (3) can be obtained, for example, by the following methods (d) to (f).
Method (d)
An adhesive layer (2 ') is formed on one surface of the reinforcing sheet (3), and a double-sided release sheet (4) is laminated on the other surface of the adhesive layer (2'). Next, a reinforcing sheet adhesive layer (6) is formed on the surface of the reinforcing sheet (3) that is not in contact with the pressure-sensitive adhesive layer (2 '), and the other of the reinforcing sheet adhesive layer (6). A foam sheet (1) is laminated on the surface. Next, an adhesive layer (2) is formed on the other surface of the foam sheet (1), and the other surface of the adhesive layer (2) and the other surface of the double-sided release sheet (4) (adhesive layer) (2 ') is wound in a roll shape so as to be in contact with the surface not contacted.
Method (e)
An adhesive layer (2 ') is formed on one surface of the reinforcing sheet (3), and a release-treated surface of a single-sided release sheet (5') is laminated on the other surface of the adhesive layer (2 '). Next, a reinforcing sheet adhesive layer (6) is formed on the surface of the reinforcing sheet (3) that is not in contact with the pressure-sensitive adhesive layer (2 '), and the other of the reinforcing sheet adhesive layer (6). A foam sheet (1) is laminated on the surface. Next, an adhesive layer (2) is formed on the other surface of the foam sheet (1), and a release-treated surface of a single-sided release sheet (5) is laminated on the other surface of the adhesive layer (2).
Method (F)
The pressure-sensitive adhesive layer (2) is formed on the release-treated surface of the single-sided release sheet (5), and the foam sheet (1) is laminated on the other surface of the pressure-sensitive adhesive layer (2). An adhesive layer for a reinforcing sheet (6) is laminated on the other surface, and then a reinforcing sheet (3) is laminated on the other surface of the adhesive layer for a reinforcing sheet (6). The pressure-sensitive adhesive layer (2 ′) is formed on the surface of the pressure-sensitive adhesive layer, and the release-treated surface of the single-sided release sheet (5 ′) is laminated on the other surface of the pressure-sensitive adhesive layer (2 ′).
[0058]
As a method of applying each adhesive and the adhesive for the reinforcing sheet on the release sheet (4), (5), (5 ′), the foam sheet (1) or the reinforcing sheet (3), for example, a comma coater, It can be performed using a die coater, a lip coater, a kiss coater, a gravure coater, or the like. When a comma coater is used, the viscosity of the pressure-sensitive adhesive or the adhesive for the reinforcing sheet is preferably about 0.1 to 100 Pa · s.
[0059]
The double-sided pressure-sensitive adhesive sheet of the present invention has a ² If the difference between the maximum thickness and the minimum thickness is larger than 100 μm, it becomes difficult to polish the object to be polished to a uniform thickness. That is, a pressure difference occurs between a thick portion and a thin portion when polishing by applying pressure. For this reason, when polishing accuracy is required, 1 m ² The difference between the maximum thickness and the minimum thickness is preferably within 80 μm, more preferably within 60 μm.
In addition, 1 m of the double-sided pressure-sensitive adhesive sheet according to the present invention is used. ² The average thickness within is, as a whole, to obtain the desired 25% compression hardness when pressure is applied during polishing and to resist shear deformation caused by horizontal shear forces on the double-sided adhesive sheet. Therefore, the thickness is preferably 400 μm to 2.5 mm. The above-mentioned shear deformation deteriorates the polishing characteristics.
The measurement of the thickness of the double-sided pressure-sensitive adhesive sheet was performed using a probe having a diameter of 10 mm and an applied load of 50 g / cm. ² , A digital measuring instrument capable of displaying 1 μm digits.
[0060]
It is important that the 25% compression hardness of the double-sided pressure-sensitive adhesive sheet according to the present invention as a whole is 0.1 to 1.3 MPa, and preferably 0.15 to 0.7 MPa. The reason why the 25% compression hardness of the double-sided pressure-sensitive adhesive sheet is higher than the 25% compression hardness of the foam sheet is as follows. The layers constituting the double-sided pressure-sensitive adhesive sheet are composed of a foam layer, a pressure-sensitive adhesive layer and a reinforcing sheet layer each having a thickness, and when the double-sided pressure-sensitive adhesive sheet is compressed by 25%, the compression deformation of the foam is faster than other layers. This is because the foam is compressed by 25% or more.
The “25% compression hardness of the double-sided pressure-sensitive adhesive sheet” here is the same as the “25% compression hardness of the foamed sheet” in that the double-sided pressure-sensitive adhesive sheet is subjected to the general conditions of a test described in JIS K 6400, ie, a temperature of 23. After standing for 24 hours or more in an environment of 50 ° C. and a relative humidity of 50%, the double-sided pressure-sensitive adhesive sheet was punched into 30 mm × 30 mm, and the sheets were stacked so as to have a thickness of about 10 mm. This refers to the stress when the entire surface of the combined sheet is compressed in parallel at a speed of 50 mm / min and compressed by 25% from the original thickness.
If the 25% compression hardness of the double-sided pressure-sensitive adhesive sheet is less than 0.1 MPa, the double-sided pressure-sensitive adhesive sheet becomes too flexible, so that local minute steps on the object to be polished can be easily eliminated, but “undulations” cannot be eliminated. . On the other hand, when the pressure exceeds 1.3 MPa, the double-sided pressure-sensitive adhesive sheet becomes too hard, so that it takes a long time to eliminate local minute steps and “undulations”.
[0061]
The double-sided pressure-sensitive adhesive sheet has been described above. As another aspect of the present invention, a polishing cloth laminate in which a polishing cloth is laminated on the double-sided pressure-sensitive adhesive sheet is provided. The polishing cloth is not particularly limited, and a conventionally known polishing cloth can be used. Preferably, as the polishing cloth, synthetic leather suede or velor, hard urethane foam or the like can be used.
In this case, the polishing cloth may be provided on the double-sided pressure-sensitive adhesive sheet in advance, or may be provided on the double-sided pressure-sensitive adhesive sheet during use.
[0062]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples, but these do not limit the scope of the present invention. In the following Examples and Comparative Examples, parts and% are by weight unless otherwise specified.
[0063]
[Creation example 1]
1. 100 parts of polyethylene glycol having a molecular weight of 3000, 5 parts of 1,4-butanediol, 0.5 part of an amine catalyst (DABCO) as a catalyst, and a silicone foam stabilizer (KF6002; manufactured by Shin-Etsu Chemical Co., Ltd.) as a foam stabilizer. 5 parts, 0.1 part of water as a foaming agent, and 40 parts of MDI as an isocyanate are mixed and stirred, and heated at 100 ° C. for 15 minutes while coating and foaming on a release liner, thereby reducing the compressive stress. Rate is 5.1%, difference of compressive stress attenuation rate is 1.1%, 1m ² The average thickness inside is 1252μm, 1m ² The difference between the maximum thickness and the minimum thickness was 30 μm to obtain a polyether flexible polyurethane foam sheet (1-1).
[0064]
[Creation example 2]
100 parts of polyoxypropylene triol having a molecular weight of 3000, 10 parts of 1,4-butanediol, 0.5 part of an amine catalyst (DABCO) as a catalyst, and a silicone foam stabilizer as a foam stabilizer (KF6002; manufactured by Shin-Etsu Chemical Co., Ltd.) 2.5 parts, 0.1 part of water as a foaming agent, and 40 parts of MDI as an isocyanate were mixed and stirred, and heated at 100 ° C. for 15 minutes while coating and foaming on a release liner. Stress decay rate of 8.6%, compressive stress decay rate difference of 1.4%, 1m ² The average thickness is 1248μm, 1m ² A polyester-type flexible polyurethane foam sheet (1-2) having a difference between the maximum thickness and the minimum thickness of 55 μm was obtained.
[0065]
[Creation example 3]
Compressive stress decay rate was 7.3% in the same manner as in Preparation Example 2 except that the amount of polyoxypropylene triol having a molecular weight of 3000 was set to 100 parts and the amount of 1,4-butanediol was changed to 5 parts. , Compressive stress decay rate difference 1.3%, 1m ² The average thickness is 1338μm, 1m ² A polyester-type flexible polyurethane foam sheet (1-3) having a difference of 155 μm between the maximum thickness and the minimum thickness was obtained.
[0066]
[Creation example 4]
Except that the amount of polyethylene glycol having a molecular weight of 3000 was 100 parts and the amount of 3-methyl-1,6-hexanediol was 5 parts, the compressive stress decay rate was 5. 3%, difference in compressive stress decay rate 1.1%, 1m ² The average thickness inside is 1202μm, 1m ² The difference between the maximum thickness and the minimum thickness was 30 [mu] m to obtain a polyether flexible polyurethane foam sheet (1-5).
[0067]
[Creation example 5]
Compressive stress decay rate was 8.4% in the same manner as in Preparation Example 2 except that the amount of polyoxypropylene triol having a molecular weight of 3000 was set to 100 parts, and the amount of 1,4-butanediol was changed to 8 parts. , Compressive stress decay rate difference 1.3%, 1m ² Average thickness of 1308μm, 1m ² The difference between the maximum thickness and the minimum thickness was 51 μm to obtain a polyester-type flexible polyurethane foam sheet (1-6).
[0068]
[Creation example 6]
100 parts of polyoxypropylene triol having a molecular weight of 3000, 6 parts of 1,4-butanediol, 0.2 part of a tin catalyst (DBTDL) as a catalyst, and a silicone foam stabilizer as a foam stabilizer (F-304; Shin-Etsu Chemical Co., Ltd.) And 1.5 parts of water, 0.1 part of water as a foaming agent, and 40 parts of MDI were mixed and stirred, heated at 100 ° C. for 15 minutes while coating and foaming on a release liner, and the compressive stress decay rate was measured. Is 8.3%, the difference in compressive stress attenuation rate is 1.3%, 1 m ² Average thickness of 1198μm, 1m ² A polyester flexible polyurethane foam sheet (1-7) having a difference between the maximum thickness and the minimum thickness of 155 μm was obtained.
[0069]
Embodiment 1
In this example, as shown in FIG. 6, a release sheet (4) / adhesive layer (2 ') / reinforcement sheet (3) / adhesive layer for reinforcement sheet (6) / foam sheet (1) / adhesive A double-sided pressure-sensitive adhesive sheet (10) supported on a double-sided release sheet (4) of the embodiment composed of the agent layer (2) was prepared.
That is, first, 100 parts of an adhesive containing an adhesive acrylic resin [manufactured by Toyo Ink Mfg. Co., Ltd.] and 3 parts of an isocyanate derivative-based curing agent [manufactured by Toyo Ink Mfg.] Are stirred and mixed. The coating liquid is applied to the entire surface of a polyethylene terephthalate film (thickness = 75 μm) as a reinforcing sheet (3) so as to have a dry film thickness of 30 μm with a comma coater, and is wound while forming an adhesive layer (2 ′). A polyethylene terephthalate release sheet (4), which has been subjected to a double-sided release treatment at the time of removal, is laminated on the pressure-sensitive adhesive layer (2 ') at a pressure of 0.3 MPa, and a release sheet (4) / pressure-sensitive adhesive layer (2') / reinforcement An adhesive sheet (C) comprising the sheet layer (3) was obtained.
[0070]
Next, on the reinforcing sheet (3) side of the pressure-sensitive adhesive sheet (C), the same pressure-sensitive adhesive composition coating liquid as described above is applied to the entire surface so as to have the same dry film thickness by the same method, and the adhesive for the reinforcing sheet is applied. While forming the layer (6), the polyurethane foam sheet (1-1) produced in Preparation Example 1 was laminated on the adhesive layer (6) for the reinforcing sheet at the time of winding at a pressure of 0.3 MPa and peeled off. A pressure-sensitive adhesive sheet (B) composed of sheet (4) / pressure-sensitive adhesive layer (2 ′) / reinforced sheet layer (3) / adhesive layer for reinforcing sheet (6) / foam sheet (1-1) was obtained.
[0071]
Finally, using the polyethylene terephthalate release sheet as a process film, the same pressure-sensitive adhesive composition coating solution as described above is applied over the entire surface by the same method so as to have the same dry film thickness, and the pressure-sensitive adhesive layer (2) is formed. After laminating the pressure-sensitive adhesive layer (2) on the foam sheet (1-1) side at a pressure of 0.3 MPa on the pressure-sensitive adhesive layer (2) at the time of winding, the process film was peeled off, as shown in FIG. Adhesive sheet (4) / adhesive layer (2 ') / reinforced sheet (3) / adhesive layer for reinforcing sheet (6) / foam sheet (1-1) / adhesive layer (2) The compressive stress decay rate on the agent layer (2 ') side is 5.4%, and the difference in compressive stress decay rate is 1.2%, 1 m ² The average thickness inside is 1417μm, 1m ² The adhesive sheet (A-1) having a difference between the maximum thickness and the minimum thickness of 31 μm was obtained.
[0072]
Embodiment 2
6 in the same manner as in Example 1 except that the urethane resin foam sheet (1-2) produced in Preparation Example 2 was used instead of the foam sheet (1-1) used in Example 1. As shown in the figure, the release sheet (4) / the pressure-sensitive adhesive layer (2 ') / the reinforcing sheet (3) / the adhesive layer for the reinforcing sheet (6) / the foam sheet (1-2) / the pressure-sensitive adhesive layer (2) And the compressive stress decay rate on the pressure-sensitive adhesive layer (2 ′) side is 8.9%, and the difference in compressive stress decay rate is 1.5%, 1 m ² The average thickness inside is 1413μm, 1m ² The pressure-sensitive adhesive sheet (A-2) in which the difference between the maximum thickness and the minimum thickness was 56 μm was obtained.
[0073]
[Comparative Example 1]
6 in the same manner as in Example 1 except that the urethane resin foam sheet (1-3) manufactured in Preparation Example 3 was used instead of the foam sheet (1-1) used in Example 1. As shown in the figure, the release sheet (4) / adhesive layer (2 ') / reinforcement sheet (3) / adhesive layer for reinforcement sheet (6) / foam sheet (1-3) / adhesive layer (2) And the compressive stress decay rate on the pressure-sensitive adhesive layer (2 ') side is 7.5%, and the compressive stress decay rate difference is 1.3%, 1 m ² The average thickness inside is 1503μm, 1m ² The pressure-sensitive adhesive sheet (A-3) in which the difference between the maximum thickness and the minimum thickness was 157 μm was obtained.
[0074]
[Comparative Example 2]
Instead of the foam sheet (1-1) used in Example 1, the compressive stress decay rate was 24.3%, and the compressive stress decay rate difference was 3.5%, 1 m. ² The average thickness is 1228μm, 1m ² As shown in FIG. 6, the same procedure as in Example 1 was carried out except that a urethane resin foam sheet (1-4) having a difference of 41 μm between the maximum thickness and the minimum thickness was used. Adhesive layer (2 ') / Reinforcing sheet (3) / Adhesive layer for reinforcing sheet (6) / Foam sheet (1-4) / Adhesive layer (2), side of the adhesive layer (2') Has a compressive stress decay rate of 25.5% and a compressive stress decay rate difference of 3.7%, 1 m ² The average thickness is 1393μm, 1m ² The pressure-sensitive adhesive sheet (A-4) in which the difference between the maximum thickness and the minimum thickness was 42 μm was obtained.
[0075]
Embodiment 3
In this example, as shown in FIG. 1, a double-sided release sheet (4) having a mode of release sheet (4) / adhesive layer (2 ′) / foam sheet (1) / adhesive layer (2) A supported double-sided pressure-sensitive adhesive sheet (10) was prepared.
That is, first, 100 parts of an adhesive containing an adhesive acrylic resin [manufactured by Toyo Ink Mfg. Co., Ltd.] and 3 parts of an isocyanate derivative-based curing agent [manufactured by Toyo Ink Mfg.] Are stirred and mixed. The coating liquid is applied to the entire surface of the polyethylene terephthalate release sheet (4) which has been subjected to a double-sided release treatment with a comma coater so as to have a dry film thickness of 30 μm. The flexible polyurethane foam sheet (1-5) produced in Preparation Example 4 was laminated on the pressure-sensitive adhesive layer (2 ') at a pressure of 0.3 MPa, and a release sheet (4) / pressure-sensitive adhesive layer (2') / An adhesive sheet (D) comprising the foam sheet (1-5) was obtained.
[0076]
Next, using a polyethylene terephthalate release sheet as a process film, the same pressure-sensitive adhesive composition coating solution as described above is applied over the entire surface in the same manner so as to have the same dry film thickness, and while forming a pressure-sensitive adhesive layer (2), At the time of winding, after laminating the foam sheet (1-5) side of the pressure-sensitive adhesive sheet (D) to the pressure-sensitive adhesive layer (2) at a pressure of 0.3 MPa, the process film was peeled off, and as shown in FIG. Composed of release sheet (4) / pressure-sensitive adhesive layer (2 ') / foam sheet (1-5) / pressure-sensitive adhesive layer (2), 1 m ² The average thickness inside is 1263μm, 1m ² Among them, the pressure-sensitive adhesive sheet (E-1) having a difference between the maximum thickness and the minimum thickness of 31 μm, a compressive stress decay rate of 5.3%, and a compressive stress decay rate difference of 1.2% was obtained.
[0077]
Embodiment 4
1 in the same manner as in Example 3 except that the urethane resin foam sheet (1-6) produced in Preparation Example 5 was used instead of the foam sheet (1-5) used in Example 3. As shown in the figure, it is composed of a release sheet (4) / pressure-sensitive adhesive layer (2 ') / foam sheet (1-6) / pressure-sensitive adhesive layer (2), and a compressive stress decay rate on the pressure-sensitive adhesive layer (2') side. 8.5%, compressive stress decay rate difference 1.3%, 1m ² Average thickness of 1368μm, 1m ² The adhesive sheet (E-2) in which the difference between the maximum thickness and the minimum thickness was 52 μm was obtained.
[0078]
[Comparative Example 3]
1 in the same manner as in Example 3 except that the urethane resin foam sheet (1-7) produced in Preparation Example 6 was used instead of the foam sheet (1-5) used in Example 3. As shown in the figure, it consists of a release sheet (4) / pressure-sensitive adhesive layer (2 ') / foam sheet (1-7) / pressure-sensitive adhesive layer (2), and the compressive stress decay rate on the pressure-sensitive adhesive layer (2') side Is 8.4%, the difference in compressive stress attenuation rate is 1.3%, 1 m ² The average thickness inside is 1259μm, 1m ² The adhesive sheet (E-3) in which the difference between the maximum thickness and the minimum thickness was 157 μm was obtained.
[0079]
[Comparative Example 4]
Instead of the foam sheet (1-5) used in Example 3, the compressive stress decay rate was 24.8%, and the compressive stress decay rate difference was 3.5%, 1 m. ² Average thickness of 1258μm, 1m ² In the same manner as in Example 3 except that the urethane resin foam sheet (1-8) having a difference between the maximum thickness and the minimum thickness of 51 μm was used, as shown in FIG. Composed of pressure-sensitive adhesive layer (2 ') / foam sheet (1-8) / pressure-sensitive adhesive layer (2), the compressive stress decay rate on the pressure-sensitive adhesive layer (2') side is 25.0%, and the difference in compressive stress decay rate Is 3.5%, 1m ² The average thickness inside is 1319μm, 1m ² The pressure-sensitive adhesive sheet (E-4) in which the difference between the maximum thickness and the minimum thickness was 52 μm was obtained.
[0080]
[Polishing test]
(1) Polishing operation
The adhesive sheet (50 mm × 300 mm) obtained in each of Examples and Comparative Examples was bonded to the adhesive layer (2) side with water-resistant abrasive paper No. 1000 specified in JIS R6253, and the other adhesive layer (2 ′) After peeling off the release sheet (4) on the side, the pressure-sensitive adhesive layer (2 ') was attached to the platen side of a polishing apparatus (manufactured by Tester Sangyo Co., Ltd.).
On the other hand, the sample to be polished was mounted on the polishing apparatus such that the sample to be polished was opposed to a position parallel to the water-resistant polishing paper, and the water-resistant polishing paper was brought into contact with the sample to be polished, and a load of 0.02 MPa was applied. And a polishing operation was performed for 10 minutes at a speed of 20 m / min while supplying pure water at a flow rate of 20 mL / min.
[0081]
(2) Repetition conditions
After the polishing operation for 10 minutes described above was continuously performed 10 times, only the water-resistant abrasive paper was replaced, and the polishing operation for 10 minutes was further performed continuously for 10 times. The water-resistant abrasive paper was replaced every 10 times, and the polishing operation was performed 100 times in total for 1000 minutes.
[0082]
(3) Sample to be polished
A polycarbonate sheet (a) having a diameter of 30.0 mm, an average thickness of 0.130 mm, and a 60-degree reflection glossiness of 14.7 on one surface was passed through a pressure-sensitive adhesive layer having a thickness of 0.030 mm. A sample to be polished was attached to a 30.0 mm cylindrical indenter.
The thickness was measured with a probe diameter of 10 mm and an applied load of 50 g / cm. ² , A digital measuring instrument capable of displaying 1 μm digits.
[0083]
(4) Evaluation method
The thickness of the polycarbonate sheet (a) of the sample to be polished was measured at 13 places before and after polishing, and those with a small degree of variation were evaluated as “○”, those with a large degree of variation were evaluated as “×”, and those between ○ and × were evaluated. It was evaluated on a three-point scale, such as “△”.
[0084]
(5) Result
Table 1 shows the results. If the difference between the maximum and minimum thicknesses of the double-sided pressure-sensitive adhesive sheet is large, the polishing amount varies. Even if the difference between the maximum and minimum thicknesses is small, good polishing cannot be achieved if the compressive stress decay rate is high, and if the compressive stress decay rate difference is large, swelling deformation proceeds and the polishing amount varies.
[0085]
[Table 1]

[0086]
【The invention's effect】
When a polishing cloth is attached to a polishing apparatus using the double-sided pressure-sensitive adhesive sheet of the present invention and the object to be polished is polished, the surface of the wafer is uniformly reduced in height without causing swelling deformation due to polishing slurry during polishing. Can be polished.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a double-sided pressure-sensitive adhesive sheet of the present invention comprising a foam sheet and pressure-sensitive adhesive layers on both surfaces thereof, in which a double-sided release sheet is provided in one of the pressure-sensitive adhesive layers. .
FIG. 2 is a cross-sectional view schematically showing a double-sided pressure-sensitive adhesive sheet of the present invention comprising a foam sheet and pressure-sensitive adhesive layers on both surfaces thereof, in which a single-sided release sheet is provided in both pressure-sensitive adhesive layers. .
FIG. 3 shows a double-sided pressure-sensitive adhesive sheet of the present invention comprising a foam sheet, a pressure-sensitive adhesive layer on one surface thereof, a reinforcing sheet on the other surface, and a pressure-sensitive adhesive layer on the reinforcing sheet. It is sectional drawing which shows typically the state in which the double-sided release sheet was provided in the sheet side adhesive layer.
FIG. 4 shows a double-sided pressure-sensitive adhesive sheet of the present invention comprising a foam sheet, a pressure-sensitive adhesive layer on one surface thereof, a reinforcing sheet on the other surface, and a pressure-sensitive adhesive layer on the reinforcing sheet. It is sectional drawing which shows typically the state where the double-sided release sheet was provided in the adhesive layer on the opposite side to the sheet-side adhesive layer.
FIG. 5 shows a double-sided pressure-sensitive adhesive sheet of the present invention comprising a foam sheet, a pressure-sensitive adhesive layer on one surface thereof, a reinforcing sheet on the other surface, and a pressure-sensitive adhesive layer on the reinforcing sheet; FIG. 4 is a cross-sectional view schematically showing a state in which a single-sided release sheet is provided in the pressure-sensitive adhesive layer of FIG.
FIG. 6 shows a foam sheet, an adhesive layer on one surface thereof, an adhesive layer for a reinforcing sheet on the other surface, a reinforcing sheet on the adhesive layer for the reinforcing sheet, and on the reinforcing sheet. FIG. 2 is a cross-sectional view schematically showing a state in which a double-sided release sheet is provided in the reinforcing sheet-side pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet of the present invention comprising the above-mentioned pressure-sensitive adhesive layer.
FIG. 7 shows a foam sheet, an adhesive layer on one surface thereof, an adhesive layer for a reinforcing sheet on the other surface, a reinforcing sheet on the adhesive layer for the reinforcing sheet, and on the reinforcing sheet. FIG. 2 is a cross-sectional view schematically showing a state in which a double-sided release sheet is provided in a pressure-sensitive adhesive layer opposite to the reinforcing sheet-side pressure-sensitive adhesive layer on a double-sided pressure-sensitive adhesive sheet of the present invention comprising the above-mentioned pressure-sensitive adhesive layer.
FIG. 8 shows a foam sheet, an adhesive layer on one surface thereof, an adhesive layer for a reinforcing sheet on the other surface, a reinforcing sheet on the adhesive layer for the reinforcing sheet, and on the reinforcing sheet. FIG. 1 is a cross-sectional view schematically showing a state in which a single-sided release sheet is provided in both pressure-sensitive adhesive layers of a double-sided pressure-sensitive adhesive sheet of the present invention comprising the above pressure-sensitive adhesive layer.
FIG. 9 is a plan view schematically showing a state in which the surface of a semiconductor wafer is polished by a CMP technique using abrasive paper stuck to a surface plate of a polishing apparatus.
[Explanation of symbols]
1 ... foam sheet; 2, 2 '... adhesive layer; 3 ... reinforcing sheet;
4: double-sided release sheet; 5, 5 ': single-sided release sheet;
6 ... adhesive layer for reinforcing sheet; 10 ... double-sided adhesive sheet;
11: polishing pad; 12: wafer.

Claims (5)

The difference between the maximum thickness and the minimum thickness within 1 m ² is 100 μm or less, and the maximum value of the compression stress in the compression test for maintaining the compression distance after compression constant, and 0.1% from the time when the maximum value of the compression stress is obtained. A double-sided pressure-sensitive adhesive sheet, wherein a compressive stress decay rate obtained from a compressive stress value after one second is 15% or less. The difference between the maximum thickness and the minimum thickness within 1 m ² is 100 μm or less, and the maximum value of the compression stress in the compression test for maintaining the compression distance after compression constant, and 0.1% from the time when the maximum value of the compression stress is obtained. 2. The double-sided pressure-sensitive adhesive sheet according to claim 1, wherein a pressure-sensitive adhesive layer has a pressure-sensitive adhesive layer on both surfaces of the foamed sheet, the compression stress attenuation rate of which is determined from the compression stress value after one second is 15% or less. In the compression test in which the foam sheet is repeatedly subjected to compression and release operations in water, the maximum value of the compression stress in the compression operation of maintaining a constant compression distance after the initial compression, and 0 from the time when the maximum value of the compression stress is obtained. The initial compressive stress decay rate obtained from the compressive stress value after 1 second, the maximum compressive stress value by the same 10,000th compression / release operation, and 0.1% from the time when the maximum compressive stress value is obtained. 3. The double-sided pressure-sensitive adhesive sheet according to claim 2, wherein a difference from a compressive stress value after the second and a 10,000th-time compressive stress attenuation rate is 2% or less. 4. The double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein a reinforcing sheet having a breaking strength of 40 MPa or more and 500 MPa or less is provided between any one of the pressure-sensitive adhesive layers and the foam sheet. A polishing cloth laminate comprising the double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 4 and a polishing cloth laminated on any one of the pressure-sensitive adhesive layers.

Images