JP2004253764A - Double-sided pressure sensitive adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure sensitive adhesive tape for fixing polishing cloth, which enables polishing of even a semiconductor wafer having smooth unevenness in height and a wafer on which local differences in level are produced during a circuit forming process, thereby the differences in height on the entire surface of the wafer can be reduced evenly along the smooth unevenness in height and the differences in level. <P>SOLUTION: The double-sided pressure sensitive adhesive sheet comprises a soft urethane foam sheet 1 and first and second pressure sensitive adhesive compound layer 2. In the soft urethane foam sheet of the double-sided pressure sensitive adhesive sheet, the difference between the maximum thickness and the minimum thickness within an area of 1 m<SP>2</SP>is not less than 0 μm and not more than 100 μm, and the water vapor permeability is not less than 0 g/m<SP>2</SP>×24h and not more than 1000 g/m<SP>2</SP>×24h. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３０】
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。
【００３１】
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。
【００３２】
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。
【００３３】
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。
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（３）として利用することができ、発泡体シート（１）と補強シート（３）との間には格別接着剤層もしくは粘着剤層（６）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。即ち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（６）を積層した場合、層間の密着性向上に効果を奏し、さら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。
【００３４】
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。
【００３５】
上記した発泡体シート（１）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５００ＭＰａ以下の補強シート（３）を、発泡体シート（１）と一方の粘着剤層（２’）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。
補強シート（３）は、種々のプラスチックシートであることが好ましく、厚さバラツキ精度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、さらに２５〜１００μｍであることがより好ましい。
また、補強シート（３）の金属イオン含有率は、発泡体シート（１）等の場合と同様の理由で、５０００ｐｐｍ以下であることが好ましく、１０００ｐｐｍ以下であることがより好ましく、５００ｐｐｍ以下であることがさらに好ましい。
【００３６】
尚、補強シート（３）を有する場合、図１〜６に示すように、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の２５％圧縮硬さが０．１〜１．３ＭＰａの範囲にあれば良く、補強シート（３）から遠い方の粘着剤層（２）面の２５％圧縮硬さが上記範囲にあることがより好ましい。
【００３７】
次に本発明における水蒸気透過率について説明する。
本発明における水蒸気透過率は、軟質ウレタン発泡体シート（１）を含む両面粘着シートの片面から他方面へ水分が透過する速度であり、この水蒸気透過率値が大きいと水分を多量に透過させ、水蒸気透過率値が小さいと水分をあまり透過しない。
本発明の両面粘着シートは、軟質ウレタン発泡体シート（１）の両面に粘着剤層（２）（２’）を設けたものであるが、水蒸気透過率値は軟質ウレタン発泡体シート（１）に依存している。軟質ウレタン発泡体シート（１）はある程度低い水蒸気透過率値を示すが、粘着剤層は水蒸気の透過を阻害するものではなく、測定できないくらい水蒸気透過率値が極めて高い。つまり、水蒸気の透過性という観点からはその値の低い部分（本発明においては軟質ウレタン発泡体シート（１））に大きく依存することは技術常識である。故に軟質ウレタン発泡体シート（１）の水蒸気透過率が、ほぼ両面粘着シートの水蒸気透過率である。
本発明における水蒸気透過率は、一般にカップ法といわれるＪＩＳ Ｚ ０２０８に準拠し、４０℃、９０％ＲＨの条件で測定した。
【００３８】
水蒸気透過率は、０であることが最も望ましく、大きくとも１０００ｇ／ｍ^２・２４ｈである。即ち、水蒸気透過率が１０００ｇ／ｍ^２・２４ｈよりも大きいと、研磨の際に使用されるスラリーが両面粘着シート（軟質ウレタン発泡体シート（１））にしみ込んでしまう。その結果、研磨中に両面粘着シート（軟質ウレタン発泡体シート（１））がヘタり、物性が変化してしまい、迅速かつ均一な研磨ができなくなる。
【００３９】
水蒸気透過率が１０００ｇ／ｍ^２・２４ｈ以下の軟質ウレタン発泡体シート（１）は、発泡状態と硬化状態を制御することによって得ることができる。
即ち、水蒸気透過率を直に制御する因子は、膜厚と発泡密度及びその硬化度である。
膜厚が厚ければ水蒸気透過率が低くなることは技術常識である。
また、発泡密度も同様であり、発泡密度が低いものは膜厚が厚いことと同じことを意味するので、単位厚み当たりであれば、発泡密度の低い方が水蒸気透過率は低くなる。また、水蒸気透過率の観点からは、泡のうち閉じた泡、つまり独立発泡が好ましい。
さらに、硬化度は高い方が低い水蒸気透過率を示す。つまり、硬化度が高いということは、硬化に伴い架橋ポイントが多く存在することとなり、この架橋ポイントの多さが分子構造上ポリマーネットワークを密にすることとなり、結果として水蒸気透過率を低下させ得る。
【００４０】
次に本発明において用いる粘着剤層（２）、（２’）について説明する。
本発明の両面粘着シートは、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る。補強シート（３）がある場合には、図１〜６に示すように、積層断面構成が非対称となる。この場合は、以下の（Ａ）、（Ｂ）等の形態が考えられる。
（Ａ）補強シート（３）から遠い方の粘着剤層（２）に研磨布を貼着し、補強シート（３）に近い方の粘着剤層（２’）を研磨装置に貼着する。即ち、両面粘着シートを研磨布に付着する際に、補強シート３と研磨布の間に発泡体シート１と粘着剤層２を挟むようにして付着する。
（Ｂ）補強シート（３）から遠い方の粘着剤層（２）を研磨装置に貼着し、補強シート（３）に近い方の粘着剤層（２’）に研磨布を貼着する。
即ち、両面粘着シートを研磨装置に付着する際に、補強シート３と研磨装置の間に発泡体シート１と粘着剤層２を挟むようにして付着する。
前記（Ａ）（Ｂ）の形態の内、研磨布積層体を研磨装置から除去する作業の観点からは（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、粘着剤層（２）、（２’）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、粘着剤層（２）は、研磨布および発泡体シート（１）に貼着し得ることが必要であり、一方粘着剤層（２’）は、補強シート（３）およ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（１）の素材や表面状態、補強シート（３）の素材や表面状態等を考慮して選択すればよい。
【００４１】
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。
また、粘着剤層（２）、（２’）は、貼着時およ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。
さらに研磨後に、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。即ち、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。
【００４２】
さらに発泡体シート（１）や補強シート（３）の場合と同様に粘着剤層（２）、（２’）の場合も、金属イオンが溶出しないか、又は実質的に金属イオンを含有しないこと、具体的には含有率が多くとも５０００ｐｐｍであることが好ましく、１０００ｐｐｍ以下であることがより好ましく、５００ｐｐｍ以下であることがさらに好ましい。
このような粘着剤層（２）、（２’）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、中でも金属イオンが混入し難いという点からウレタン系粘着剤、アクリル系粘着剤が好ましく、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さらに好ましい。
【００４３】
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、所望により粘着剤層もしくは接着剤層（６）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粘着剤層もしくは接着剤層（６）は、発泡体シート（１）と補強シート（３）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「接着剤」はいわゆる感圧性接着剤（粘着剤）以外の接着剤という意味である。粘着剤としては（２）、（２’）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。
両面粘着シートを研磨布およ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（２）、（２’）を用い得るのに対し、発泡体シート（１）と補強シート（３）とを相互に固定するための層としては、粘着剤層の他、接着剤層も用いることができる。発泡体シート（１）と補強シート（３）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、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、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。
さらに発泡体シート（１）の場合と同様に粘着剤もしくは接着剤層（６）も、金属イオンを溶出しないことが好ましく、実質的に金属イオンを含有しないことが好ましい。
【００４４】
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、両面剥離処理してなるもの（４）と片面剥離してなるもの（５）、（５’）とがある。いずれの剥離シートも粘着剤層（２）、（２’）を被覆した後、粘着剤層（２）、（２’）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。
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、また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。
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７，８に示されるように、発泡体シート（１）、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１〜３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）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’）を両面粘着シートの片面もしくは両面に配置する構成としてもよい。さらに、図４〜６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）、粘着剤層（２）（２’）、および粘着剤層もしくは接着剤層（６）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’）を両面粘着シートの片面もしくは両面に配置する構成としてもよい。
【００４５】
発泡体シート（１）の両面側に粘着剤層（２）（２’）が設けられてなる本発明の両面粘着シートでのうち、補強シート（３）を有しない両面粘着シートは、例えば以下に示す（イ）〜（ハ）のような方法で得ることができる。
〔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。
【００４６】
〔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。
【００４７】
〔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。
【００４８】
前記した補強シート（３）を有する両面粘着シートは、例えば以下に示す（ニ）〜（ヘ）のような方法で得ることができる。
〔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）の面に粘着剤層（６）を形成し、該粘着剤層（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）の面に粘着剤層（６）を形成し、該粘着剤層（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）の他方の面に粘着剤層（６）を積層し、次いで該粘着剤層（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。
【００４９】
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。コンマコーターを用いる場合、粘着剤の粘度は０．１〜１００Ｐａ・ｓ程度が良好である。
【００５０】
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。
【００５１】
また本発明の両面粘着シートは、両面粘着シートとしても、１ｍ^２内の最大厚みと最小厚みとの差が０以上１００μｍ以内、水蒸気透過率が０以上１０００ｇ／ｍ^２・２４ｈ以下であることが好ましい。
【００５２】
両面粘着シートの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。つまり、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、両面粘着シートの１ｍ^２内の平均厚さは、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。
【００５３】
両面粘着シートの２５％圧縮硬さは、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。
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、即ち温度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。
【００５４】
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剪断変形を起こしやすいので、被研磨体全面の表面膜厚を均一に研磨することが難しくなる傾向にある。一方、２５％圧縮硬さが、１．３ＭＰａを越えると両面粘着シートが硬くなる傾向にあるので、被研磨体表面の「凹凸」および「うねり」に追随しないで標高の高い部分を優先的に研磨するので、被研磨体全面の表面膜厚を均一に研磨することが難しくなる傾向にある。
【００５５】
【実施例】
実施例を挙げて本発明を詳細に説明するが本発明が以下の実施例に限定されないことはいうまでもない。
【００５６】
【作成例１】
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、触媒としてのアミン触媒（ＤＡＢＣＯ）０．５部、シリコーン整泡剤としての末端ＯＨ基の反応型シリコーン整泡剤（ＫＦ６００１；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、１ｍ^２内の平均厚さが１５０２μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３０μｍ、水蒸気透過率が６３ｇ／ｍ^２・２４ｈ、金属イオン含有率が１２ｐｐｍ、破断強度１．７ＭＰａの軟質ポリウレタン発泡体シート（１−１）を得た。
【００５７】
【作成例２】
実施例１と同様にシリコーン整泡剤としてＮＨ基含有の反応型シリコン整泡剤（ＫＦ８０１０；信越化学工業社製）を２．５部使用し、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、１ｍ^２内の平均厚さが１５６８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が７４μｍ、水蒸気透過率が６１ｇ／ｍ^２・２４ｈ、金属イオン含有率１４ｐｐｍ、破断強度１．７ＭＰａの軟質ポリウレタン発泡体シート（１−２）を得た。
【００５８】
【作成例３】
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、シリコーン整泡剤としての非反応型シリコーン（Ｆ−３０４；信越化学工業社製）１．５部、及び発泡剤としての水０．１部と、セル径が大のウレタンの製造のために、窒素量を少なくして、ＭＤＩ４０部とを混合撹拌し、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、１ｍ^２内の平均厚さが１６９８μｍ、１ｍ^２内の最大厚みと最小厚みとの差が２５０μｍ、水蒸気透過率が１９８９ｇ／ｍ^２・２４ｈ、金属イオン含有率１２０００ｐｐｍ、破断強度１．３ＭＰａの軟質ポリウレタン発泡体シート（１−３）を得た。
【００５９】
【実施例１】
粘着性アクリル樹脂を含む粘着剤（東洋インキ製造（株）製、金属イオン含有率１１ｐｐｍ）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）となる厚さ７５μｍ、破断強度２３０ＭＰａのポリエチレンテレフタレートフィルム（金属イオン含有率１２ｐｐｍ）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。
【００６０】
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、粘着剤層（６）を形成しつつ、巻き取り時に該粘着剤層（６）に作成例１で製造した軟質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／粘着剤層（６）／発泡体シート（１−１）からなる粘着シート（Ｂ）を得た。
【００６１】
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４に示すような剥離シート（４）／粘着剤層（２’）／補強シート（３）／粘着剤層（６）／発泡体シート（１−１）／粘着剤層（２）からなる、１ｍ^２内の平均厚さが１６６７μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３２μｍ、破断強度１０ＭＰａの粘着シート（Ａ−１）を得た。
【００６２】
【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で製造した軟質ポリウレタン発泡体シート（１−２）を用いた以外は実施例１と同様にして、剥離シート（４）／粘着剤層（２’）／補強シート（３）／粘着剤層（６）／発泡体シート（１−２）／粘着剤層（２）からなる、図４に示す構成と同様な構成であって、１ｍ^２内の平均厚さが１７３３μｍ、１ｍ^２内の最大厚みと最小厚みとの差が７５μｍ、破断強度１０ＭＰａとなる粘着シート（Ａ−２）を得た。
【００６３】
【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で製造した軟質ポリウレタン発泡体シート（１−３）を用いた以外は実施例１と同様にして、剥離シート（４）／粘着剤層（２’）／補強シート（３）／粘着剤層（６）／発泡体シート（１−３）／粘着剤層（２）からなる、図４に示す構成と同様な構成であって、１ｍ^２内の平均厚さが１８６３μｍ、１ｍ^２内の最大厚みと最小厚みとの差が２５３μｍ、破断強度９ＭＰａの粘着シート（Ａ−３）を得た。
【００６４】
【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、１ｍ^２内の平均厚さが１２８９μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３１０μｍ、水蒸気透過率が４３７１ｇ／ｍ^２・２４ｈ、金属イオン含有率１８１ｐｐｍ、破断強度３０ＭＰａの不織布含浸型ポリウレタン発泡体シート（１−４）を用いた以外は実施例１と同様にして、剥離シート（４）／粘着剤層（２’）／補強シート（３）／粘着剤層（６）／発泡体シート（１−４）／粘着剤層（２）からなる、図４に示す構成と同様な構成であって、１ｍ^２内の平均厚さが１４５４μｍ、１ｍ^２内の最大厚みと最小厚みとの差が１３２μｍ、破断強度２８ＭＰａの粘着シート（Ａ−４）を得た。
【００６５】
【実施例３】
粘着性アクリル樹脂を含む粘着剤（東洋インキ製造（株）製、金属イオン含有率１１ｐｐｍ）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）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１で製造した軟質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’）／発泡体シート（１−１）からなる粘着シート（Ｄ）を得た。
【００６６】
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（１−１）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７に示すような剥離シート（４）／粘着剤層（２’）／発泡体シート（１−１）／粘着剤層（２）からなる、１ｍ^２内の平均厚さが１５６５μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３３μｍ、破断強度１．６ＭＰａの粘着シート（Ｅ−１）を得た。
【００６７】
【実施例４】
実施例３で用いた軟質発泡体シート（１−１）の代わりに、作成例２で製造した軟質ウレタン樹脂発泡体シート（１−２）を用いた以外は実施例３と同様にして、剥離シート（４）／粘着剤層（２’）／発泡体シート（１−６）／粘着剤層（２）からなる、図７に示す構成と同様な構成であって、１ｍ^２内の平均厚さが１６２９μｍ、１ｍ^２内の最大厚みと最小厚みとの差が７５μｍ、破断強度１．６ＭＰａとなる粘着シート（Ｅ−２）を得た。
【００６８】
【比較例３】
実施例３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）を用いた以外は実施例２と同様にして剥離シート（４）／粘着剤層（２’）／発泡体シート（１−３）／粘着剤層（２）からなる、図７に示す構成と同様な構成であって、１ｍ^２内の平均厚さが１８６３μｍ、１ｍ^２内の最大厚みと最小厚みとの差が２５２μｍ、破断強度１．６ＭＰａの粘着シート（Ｅ−３）を得た。
【００６９】
【比較例４】
実施例３で用いた発泡体シート（１−１）の代わりに、１ｍ^２内の平均厚さが１２８９μｍ、１ｍ^２内の最大厚みと最小厚みとの差が３１０μｍ、水蒸気透過率が４３７１ｇ／ｍ^２・２４ｈ、金属イオン含有率１８１ｐｐｍ、破断強度３０ＭＰａの不織布含浸型ポリウレタン発泡体シート（１−４）を用いた以外は実施例２と同様にして剥離シート（３）／粘着剤層（２’）／発泡体シート（１−４）／粘着剤層（２）からなる、図７に示す構成と同様な構成であって、１ｍ^２内の平均厚さが１３４９μｍ、１ｍ^２内の最大厚みと最小厚みとの差が１８９μｍ、破断強度２８ＭＰａの粘着シート（Ｅ−４）を得た。
【００７０】
［研磨試験］
実施例および比較例で得られた粘着シート（５０ｍｍ×５０ｍｍ）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、粘着剤層（２’）側を、テスター産業社製研磨装置の定盤側に貼着した。
他方、前記研磨装置に、下記凸状被研磨試料の凸状面が前記耐水研磨紙と並行な位置に対向するように凸状被研磨試料を装着し、前記耐水研磨紙と下記凸状被研磨試料とを接触せしめ、荷重２００ｇｒ／ｃｍ^２の圧力が掛かるようにし、２０ｍｌ／分の流量で純水を供給しながら、２０ｍ／分の速度で、１０分間研磨作業を行った。この研磨作業を１００回（都合約２０時間）行った。
【００７１】
＜被研磨試料＞
６０ｍｍ×３００ｍｍ、平均厚さ２．０２ｍｍのステンレス板（ＳＵＳ３０４）に、０．０３０ｍｍ厚さの粘着剤層を介して、６０ｍｍ×３００ｍｍ、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）の他の面を積層し、該ポリカーボネートのシート（ａ）のほぼ中央に、０．０３０ｍｍ厚さの粘着剤層を介して、１５ｍｍ×２５０ｍｍ、平均厚さ０．１３０ｍｍ、一方の面の６０度反射光沢度が１４．７であるポリカーボネートのシート（ｂ）の他の面を積層し、低部が（ａ）、高部が（ｂ）からなる凸状の被研磨試料とした。
【００７２】
＜評価方法＞
被研磨試料のポリカーボネートシート（ａ）および（ｂ）の平均厚さ、および６０度反射光沢度を研磨の前後でそれぞれ測定し、（ｂ）の平均厚さ減量（ｂ１）／（ａ）の平均厚さ減量（ａ１）、および（ｂ）の６０度反射光沢度（ｂ２）／（ａ）の６０度反射光沢度（ａ２）を求め、（ｂ１）／（ａ１）、（ｂ２）／（ａ２）の値から以下のように評価した。

両面粘着シートの最大最小厚みの差が１００μｍより大きいと、ポリカーボネートシートに均一に圧力が伝わらず、均一な研磨が進行しない。さらに、水蒸気透過率が１０００ｇ／ｍ^２・２４ｈを超えると、経時により膨潤変形が進行し、シート厚さバラツキを発生させ、均一な研磨が進行しない。
【００７３】
【表１】

【００７４】
【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ことによって、被研磨体の「凹凸」と「うねり」とを一連の工程で又は同時に、かつ短時間で消去することができる。
【図面の簡単な説明】
【図１】本発明の両面粘着シートに両面剥離シートを積層した状態の断面図（補強シート（３）のある場合）
【図２】本発明の両面粘着シートに両面剥離シートを積層した状態の断面図（補強シート（３）のある場合）
【図３】本発明の両面粘着シートに片面剥離シートを積層した状態の断面図（補強シート（３）のある場合）
【図４】本発明の両面粘着シートに両面剥離シートを積層した状態の断面図（補強シート（３）のある場合であって、該補強シート（３）と発泡体シート（１）との間に粘着剤層又は接着剤層（６）があるもの）
【図５】本発明の両面粘着シートに両面剥離シートを積層した状態の断面図（補強シート（３）のある場合であって、該補強シート（３）と発泡体シート（１）との間に粘着剤層又は接着剤層（６）があるもの）
【図６】本発明の両面粘着シートに片面剥離シートを積層した状態の断面図（補強シート（３）のある場合であって、該補強シート（３）と発泡体シート（１）との間に粘着剤層又は接着剤層（６）があるもの）
【図７】本発明の両面粘着シートに両面剥離シートを積層した状態の断面図（補強シートのない場合）
【図８】本発明の両面粘着シートに片面剥離シートを積層した状態の断面図（補強シートのない場合）
【図９】被研磨体の断面図
【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）…………粘着剤層又は接着剤層[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. The present invention relates to a double-sided pressure-sensitive adhesive sheet and a laminate of a polishing cloth and a double-sided pressure-sensitive adhesive sheet used as a buffer and a fixing material for a polishing cloth adapted to a flattening process and a forming process of a metal wiring.
[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. It is becoming. In addition, with the progress of integration technology for achieving high-speed and low-volume devices, it has been desired that circuit wiring patterns can be stably drawn as fine as 0.18 μm or 0.13 μm or less. I have.
[0003]
However, a gentle thickness variation called "undulation", that is, an elevation difference exists on the entire surface of the semiconductor wafer, and may be 2 to 4 [mu] m or more. It is desirable that this undulation be small, but at the industrial level, the elimination of the undulation is not satisfactory because of 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, thereby significantly lowering the reliability of the semiconductor device circuit such as disconnection or short circuit. .
[0004]
As a solution to this problem, a chemical mechanical polishing (CMP) method has been proposed. In the CMP technology, the lower layer is made of rubber elastic material to eliminate the unevenness of the polishing allowance due to the warpage or undulation of the semiconductor wafer itself in order to keep the film thickness distribution constant and remove minute irregularities on the film surface, A polishing cloth having a two-layer structure in which a hard cloth is used as a surface layer to remove and smooth the surface irregularities generated in a semiconductor device process has been proposed (for example, see Non-Patent Document 1).
[Non-patent document 1]
Junji Watanabe et al., Pad Configuration in Surface Reference Polishing, Proc. 183
[0005]
A polyurethane-impregnated nonwoven fabric is generally used for the lower rubber elastic body used in a polishing pad having a two-layer structure as proposed.
However, since the material has air permeability, it absorbs and swells the slurry water used for polishing, causing partial or complete settling and changing rubber elasticity. (Hereinafter collectively referred to as swelling deformation). If swelling deformation progresses during polishing, the demand for uniform polishing and precision polishing cannot be met.
Therefore, before polishing, a two-layer polishing pad is preliminarily immersed in the polishing slurry for a long time, and the polyurethane-impregnated nonwoven fabric is allowed to absorb the slurry moisture sufficiently to prevent swelling deformation during polishing. there were.
[0006]
As a solution to this swelling deformation, it has been proposed to apply a waterproof material layer between the surface layer hard material and the lower layer polyurethane-impregnated nonwoven fabric, but it is not possible to prevent slurry intrusion from the side of the polishing cloth laminate. And incomplete (for example, see Patent Document 1).
[Patent Document 1]
JP-A-11-156701
[0007]
[Problems to be solved by the invention]
The present invention is directed to a polishing cloth-fixed adhesive tape that can polish a semiconductor wafer having a undulation or a wafer having a local level difference in a circuit forming process, so that the entire surface of the wafer can be uniformly polished along the undulation and the level difference. About.
More specifically, the present invention does not require immersing the polishing pad (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 (polishing cloth). The present invention relates to a polishing cloth-fixed adhesive tape which can form a laminate.
[0008]
[Means for Solving the Problems]
Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above problems, and as a result, have found that the use of silicone having a functional group as a foam stabilizer lowers the water vapor transmission rate and reduces the variation in thickness (soft urethane) foam sheet. By laminating the adhesive on both sides and arranging it on the opposite side of the polishing cloth polishing surface, it can be used for polishing without going through a special immersion treatment before polishing, even if it is a undulating semiconductor wafer The present inventors have found that unevenness on the wafer surface can be uniformly polished along the line, and the present invention has been achieved.
[0009]
That is, the present invention relates to the following items.
<1> A double-sided pressure-sensitive adhesive sheet including a soft urethane foam sheet and first and second pressure-sensitive adhesive layers, wherein the soft urethane foam sheet is 1 m ² The difference between the maximum thickness and the minimum thickness is 0 μm or more and 100 μm or less, and the water vapor transmission rate is 0 g / m 2. ² ・ More than 24h and 1000g / m ² -A double-sided pressure-sensitive adhesive sheet having a length of 24 hours or less.
<2> When at least one of (1) the metal ion content in the foam sheet and (2) the total metal ion content in the first and second pressure-sensitive adhesive layers is 0.1 ppm or more and 5000 ppm or less. The double-sided pressure-sensitive adhesive sheet according to <1>.
<3> a double-sided adhesive sheet further having a reinforcing sheet,
The reinforcing sheet has a breaking strength of 40 MPa or more and 500 MPa or less, and is provided in any one of the first and second pressure-sensitive adhesive layers and the foam sheet according to the item <1> or <2>. A double-sided pressure-sensitive adhesive sheet.
<4> The double-sided pressure-sensitive adhesive sheet according to <3>, wherein the metal ion content in the reinforcing sheet is 0.1 ppm or more and 5000 ppm or less.
<5> A polishing cloth laminate obtained by laminating the double-sided pressure-sensitive adhesive sheet according to any one of <1> to <4> and a polishing cloth.
[0010]
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.
The double-sided PSA sheet of the present invention as the first embodiment is 1 m ² The difference between the maximum thickness and the minimum thickness is 0 to 100 μm, and the water vapor transmission rate is 0 to 1000 g / m. ² -A double-sided pressure-sensitive adhesive sheet in which pressure-sensitive adhesive layers (2) and (2 ') are provided on both sides of a soft urethane foam sheet (1) having a length of 24 hours 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, a reinforcing sheet (3) having a breaking strength of 40 MPa or more and 500 MPa or less may be provided between the foam sheet (1) and one adhesive layer (2 ′).
[0011]
The foam sheet (1) used 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 (1) 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, when polishing by applying pressure, a pressure difference occurs between the thick part and the thin part. For this reason, when polishing accuracy is required, 1 m of the foam sheet (1) is required. 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 still more preferably 60 μm or less.
[0012]
1 m of the foam sheet (1) ² The average thickness in the above may be within 150 μm to 2.4 mm to resist shear deformation caused by horizontal shear force on the double-sided pressure-sensitive adhesive sheet, which deteriorates polishing characteristics when pressure is applied during polishing. preferable.
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.
[0013]
Further, the foam sheet (1) preferably has a 25% compression hardness of 0.1 to 1.0 MPa, more preferably 0.2 to 0.5 MPa.
The term “25% compression hardness of the foam sheet” as used in the present invention refers to the general condition of the test described in JISK 6400, that is, the foam sheet is kept in an environment of a temperature of 23 ° C. and a relative humidity of 50% for 24 hours or more. After placing, the foam sheet is punched into a 30 mm × 30 mm sheet, and the sheets are overlapped so as to have a thickness of about 10 mm. Under the same temperature and humidity environment, the entire surface of the overlapped sheets is parallelized at a speed of 50 mm / min. It means the stress when compressed and compressed by 25% from the original thickness.
If the 25% compression hardness of the foam sheet (1) is less than 0.1 MPa, the double-sided pressure-sensitive adhesive sheet becomes flexible and easily undergoes shear deformation, so that it is difficult to uniformly polish the surface thickness of the entire surface of the object to be polished. Tend to be. On the other hand, when the 25% compression hardness of the foam sheet (1) exceeds 1.0 MPa, the double-sided pressure-sensitive adhesive sheet tends to be hard, and therefore, the elevation without following the “irregularities” and “undulations” on the surface of the object to be polished. Therefore, there is a tendency that it is difficult to uniformly polish the surface film thickness over the entire surface of the object to be polished.
[0014]
In addition, when metal ions are eluted from the double-sided pressure-sensitive adhesive sheet during the polishing process, it contaminates the polished surface of the object to be polished, changes the inherent electrical characteristics of the metal or semiconductor, or inhibits the formation of a wiring circuit. It is preferable that metal ions are not eluted from the double-sided pressure-sensitive adhesive sheet of the present invention, or that the double-sided pressure-sensitive adhesive sheet of the present invention does not substantially contain metal ions.
That is, metal ions do not elute from the foam sheet (1) constituting the double-sided pressure-sensitive adhesive sheet or the pressure-sensitive adhesive layers (2) and (2 ′) described later, or the foam sheet (1) and the pressure-sensitive adhesive layer (2) ( Preferably, 2 ′) does not substantially contain a metal ion.
[0015]
The “metal ions” in the present invention are ions of 13 kinds of metals such as lithium, sodium, potassium, magnesium, calcium, aluminum, titanium, chromium, iron, nickel, copper, zinc and tungsten. The total amount of the metal ions can be detected by a high-frequency inductively coupled plasma emission analyzer after decomposing a sample (double-sided pressure-sensitive adhesive sheet or foam sheet (1)) by an acid decomposition method using nitric acid and sulfuric acid.
[0016]
The total amount of the metal ions contained in the double-sided PSA sheet is preferably 15000 ppm or less, more preferably 3000 ppm or less, and even more preferably 1500 ppm or less.
Further, the total amount of the metal ions contained in the foam sheet (1) is preferably 5,000 ppm or less, more preferably 1,000 ppm or less, and even more preferably 500 ppm or less.
Here, the lower limit of the amount of metal ions contained in the foam sheet (1) is preferably low, most preferably 0 ppm, but is usually about 0.1 ppm.
The same applies to the pressure-sensitive adhesive layer and the reinforcing sheet described later.
[0017]
Further, there is no particular limitation as long as the total amount of metal ions contained in the double-sided pressure-sensitive adhesive sheet is the above-mentioned total amount, but it is preferable to adopt any one of the following embodiments (1) to (3).
(1) The metal ion content in the foam sheet is 5000 ppm or less,
(2) The total metal ion content in the first and second pressure-sensitive adhesive layers is 5000 ppm or less, and
(3) The metal ion content in the foam sheet is 5000 ppm or less, and the total metal ion content in the first and second pressure-sensitive adhesive layers is 5000 ppm or less.
Above all, (3) is preferable, and (3a) the metal ion content in the foam sheet is 500 ppm or less, and the total metal ion content in the first and second pressure-sensitive adhesive layers is 500 ppm or less. More preferred.
[0018]
Examples of the foam sheet (1) used in the present invention include polyurethane, polyethylene, and silicone rubber, which can be obtained by various methods. Of these, polyurethane is preferred because the desired hardness and thickness accuracy are easily obtained.
[0019]
The polyurethane foam sheet among the foam sheets (1) 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.
[0020]
The polyol used in the present invention may be any of a polyester polyol or a polyether polyol generally used in the urethane industry, and is not particularly limited.
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, dodecane diacid, and the like.The glycol component includes ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, and 2-methyl glycol. -1,3-propanediol, 1-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,6-hexanediol, 3-methyl-1,6-hexane Diol, 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, polyoxyethylene glycol, poly Examples of oxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, and polyol components include glycerin, trimethylolpropane, polyoxypropylenetriol, 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.
[0021]
As the polyether polyol, a known polyether polyol can be used. 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.
[0022]
Examples of the polyisocyanate used in the present invention include an aromatic polyisocyanate, an aliphatic polyisocyanate, an araliphatic polyisocyanate, and an alicyclic polyisocyanate.
[0023]
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.
[0024]
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.
[0025]
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.
[0026]
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.
[0027]
Examples of the foaming agent used in the present invention include water, methylene chloride, nitrogen, air, and chlorofluorocarbon.
[0028]
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).
[0029]
Embedded image

[0030]
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.
[0031]
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.
[0032]
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.
[0033]
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.
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. If the process film is not subjected to a release treatment, the polyurethane film and the process film are firmly bonded in the process of foaming and curing of the polyurethane. Therefore, use the process film as a reinforcing sheet (3) described later. Thus, both sheets can be laminated without providing a special adhesive layer or pressure-sensitive adhesive layer (6) between the foam sheet (1) and the reinforcing sheet (3).
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 (6) is laminated on the 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.
[0034]
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.
[0035]
Since the breaking strength of the above foam sheet (1) is generally relatively low (for example, 5 MPa or less), a reinforcing sheet (3) having a breaking strength of 40 MPa or more and 500 MPa or less is prepared by combining the foam sheet (1) with one adhesive. By providing between the layer and the layer (2 '), the strength of the double-sided PSA 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.
The reinforcing sheet (3) is preferably various plastic sheets, and polyethylene terephthalate is more preferable from the viewpoint of thickness variation accuracy.
The thickness is preferably from 12 to 250 μm, more preferably from 25 to 100 μm.
Further, the metal ion content of the reinforcing sheet (3) is preferably 5000 ppm or less, more preferably 1000 ppm or less, and more preferably 500 ppm or less for the same reason as in the case of the foam sheet (1) or the like. Is more preferable.
[0036]
When the reinforcing sheet (3) is provided, as shown in FIGS. 1 to 6, the laminated cross-sectional structure of the double-sided pressure-sensitive adhesive sheet is asymmetric, but at least one surface has a 25% compression hardness of 0.1 to 1. The pressure may be in the range of 3 MPa, and more preferably the 25% compression hardness of the pressure-sensitive adhesive layer (2) surface far from the reinforcing sheet (3) is in the above range.
[0037]
Next, the water vapor transmission rate in the present invention will be described.
The water vapor transmission rate in the present invention is a rate at which moisture permeates from one side to the other side of the double-sided pressure-sensitive adhesive sheet containing the flexible urethane foam sheet (1). If the water vapor transmission rate value is low, moisture does not permeate much.
The double-sided pressure-sensitive adhesive sheet of the present invention is provided with pressure-sensitive adhesive layers (2) and (2 ′) on both sides of a soft urethane foam sheet (1), and has a water vapor permeability value of a soft urethane foam sheet (1). Depends on. The flexible urethane foam sheet (1) exhibits a somewhat low water vapor transmission value, but the pressure-sensitive adhesive layer does not inhibit the transmission of water vapor and has a very high water vapor transmission value that cannot be measured. That is, from the viewpoint of water vapor permeability, it is common general technical knowledge that it largely depends on a portion having a low value (in the present invention, the soft urethane foam sheet (1)). Therefore, the water vapor transmission rate of the flexible urethane foam sheet (1) is almost the same as the water vapor transmission rate of the double-sided pressure-sensitive adhesive sheet.
The water vapor transmission rate in the present invention was measured under the conditions of 40 ° C. and 90% RH in accordance with JIS Z 0208 which is generally called a cup method.
[0038]
The water vapor transmission rate is most preferably 0, and at most 1000 g / m2. ² ・ It is 24h. That is, the water vapor transmission rate is 1000 g / m ² If it is larger than 24 hours, the slurry used for polishing will permeate the double-sided pressure-sensitive adhesive sheet (soft urethane foam sheet (1)). As a result, the double-sided pressure-sensitive adhesive sheet (soft urethane foam sheet (1)) frays during polishing, changes physical properties, and rapid and uniform polishing cannot be performed.
[0039]
Water vapor transmission rate is 1000g / m ² -The soft urethane foam sheet (1) of 24 hours or less can be obtained by controlling the foamed state and the cured state.
That is, the factors that directly control the water vapor transmission rate are the film thickness, the foam density, and the degree of curing.
It is common technical knowledge that the greater the film thickness, the lower the water vapor transmission rate.
The same applies to the foaming density. A thing with a low foaming density means the same as a thicker film. Therefore, per unit thickness, the lower the foaming density, the lower the water vapor permeability. In addition, from the viewpoint of the water vapor transmission rate, closed bubbles among bubbles, that is, closed cells are preferable.
Further, the higher the degree of curing, the lower the water vapor transmission rate. In other words, a high degree of curing means that there are many cross-linking points along with the curing, and the number of cross-linking points makes the polymer network dense on the molecular structure, and as a result, the water vapor permeability can be reduced. .
[0040]
Next, the pressure-sensitive adhesive layers (2) and (2 ′) used in the present invention will be described.
The double-sided pressure-sensitive adhesive sheet of the present invention is located between a polishing cloth and a polishing apparatus, and is used for attaching both. When there is a reinforcing sheet (3), the laminated cross-sectional configuration becomes asymmetric as shown in FIGS. In this case, the following modes (A) and (B) are possible.
(A) A polishing cloth is stuck to the pressure-sensitive adhesive layer (2) far from the reinforcing sheet (3), and the pressure-sensitive adhesive layer (2 ') closer to the reinforcing sheet (3) is stuck to a polishing device. That is, when the double-sided pressure-sensitive adhesive sheet is adhered to the polishing cloth, the foam sheet 1 and the pressure-sensitive adhesive layer 2 are adhered between the reinforcing sheet 3 and the polishing cloth.
(B) The pressure-sensitive adhesive layer (2) remote from the reinforcing sheet (3) is adhered to a polishing device, and a polishing cloth is adhered to the pressure-sensitive adhesive layer (2 ') closer to the reinforcing sheet (3).
That is, when attaching the double-sided pressure-sensitive adhesive sheet to the polishing device, the double-sided pressure-sensitive adhesive sheet is adhered so as to sandwich the foam sheet 1 and the pressure-sensitive adhesive layer 2 between the reinforcing sheet 3 and the polishing device.
Among the modes (A) and (B), the mode (A) is preferable from the viewpoint of the operation of removing the polishing pad laminate from the polishing apparatus.
The pressure-sensitive adhesive layers (2) and (2 ') can be appropriately selected depending on which form (A) or (B) is used.
For example, when used in the form of (A), the pressure-sensitive adhesive layer (2) needs to be able to be adhered to the polishing cloth and the foam sheet (1), while the pressure-sensitive adhesive layer (2 ') Needs to be able to be attached to the reinforcing sheet (3) and the polishing device. These sticking characteristics may be selected in consideration of the material and surface condition of the foam sheet (1), the material and surface condition of the reinforcing sheet (3), and the like.
[0041]
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.
It is important that the pressure-sensitive adhesive layers (2) and (2 ′) are in a rubbery region in the temperature range at the time of sticking and when used for polishing, and the pressure-sensitive adhesive tape / sheet specified in JIS Z0237 It is preferable that the 180-degree peeling adhesive force by the test method 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 is preferably peeled off from the polishing apparatus. That is, it is preferable that the material can be firmly adhered to the polishing cloth or the polishing device during polishing, and then easily peeled off.
[0042]
Further, in the case of the pressure-sensitive adhesive layers (2) and (2 '), as in the case of the foam sheet (1) and the reinforcing sheet (3), the metal ions do not elute or contain substantially no metal ions. Specifically, the content is preferably at most 5,000 ppm, more preferably 1,000 ppm or less, and even more preferably 500 ppm or less.
Examples of the pressure-sensitive adhesive used for forming such pressure-sensitive adhesive layers (2) and (2 ′) include an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, and a rubber-based pressure-sensitive adhesive, and among them, metal ions are hardly mixed. In this respect, urethane-based pressure-sensitive adhesives and acrylic-based pressure-sensitive adhesives are preferable, and acrylic-based pressure-sensitive adhesives are more preferable in that the balance of the adhesion performance is easily ensured.
[0043]
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 be provided with a pressure-sensitive adhesive layer or an adhesive layer (6) as required.
The pressure-sensitive adhesive layer or adhesive layer (6) that can be used in the present invention is located between the foam sheet (1) and the reinforcing sheet (3), and is a layer for fixing both layers to each other. The thickness is preferably from 5 to 150 μm.
By the way, the pressure-sensitive adhesive is also called a pressure-sensitive adhesive, and is included in the adhesive in a broad sense. However, the “adhesive” in the present invention means an adhesive other than a so-called pressure-sensitive adhesive (pressure-sensitive adhesive). It is. As the pressure-sensitive adhesive, those similar to (2) and (2 ′) can be used. Regarding the water-based or solvent-based adhesive, from a general type by solvent drying to a dry lami type, 300 mm / min. Of 180 mN / 25 mm or more can be used.
While the pressure-sensitive adhesive layers (2) and (2 ') can be used as described above to attach the double-sided pressure-sensitive adhesive sheet to a polishing cloth and a polishing apparatus, the foam sheet (1) and the reinforcing sheet (3) As a layer for mutually fixing and, an adhesive layer can be used in addition to the pressure-sensitive adhesive layer. The foam sheet (1) and the reinforcing sheet (3) can be fixed via an adhesive layer since there is no special requirement that they be separated once fixed to each other. There is also a requirement that the layer positioned on the side of the polishing pad be peeled off after application, so it is important to form the layer with an adhesive instead of an adhesive.
Further, as in the case of the foam sheet (1), the pressure-sensitive adhesive or adhesive layer (6) preferably does not elute metal ions, and preferably does not substantially contain metal ions.
[0044]
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 those that are subjected to a double-sided release treatment (4) and those that are subjected to single-sided release (5) and (5 ′). After covering any of the release sheets with the pressure-sensitive adhesive layers (2) and (2 '), it is necessary that the release sheet can be easily peeled at the interface in contact with the pressure-sensitive adhesive layers (2) and (2'). Further, it is required that the pressure-sensitive adhesive does not remain 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.
Specific examples of the release sheet include various plastic films such as polyethylene terephthalate and oriented polypropylene, and paper obtained by coating 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.
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. 7 and 8, when a release sheet is provided on a double-sided pressure-sensitive adhesive sheet composed of a foam sheet (1) and a pressure-sensitive adhesive layer (2) (2 ′), a double-sided release sheet (4) or The single-sided release sheet (5) (5 ′) may be arranged on one side or both sides of the double-sided pressure-sensitive adhesive sheet. When a release sheet is provided on a double-sided pressure-sensitive adhesive sheet comprising a foam sheet (1), a pressure-sensitive adhesive layer (2) (2 ′), and a reinforcing sheet (3), as shown in FIGS. (4) Alternatively, the single-sided release sheet (5) (5 ′) may be arranged on one or both sides of the double-sided pressure-sensitive adhesive sheet. Further, as shown in FIGS. 4 to 6, a foam sheet (1), an adhesive layer (2) (2 ′), a reinforcing sheet (3), an adhesive layer (2) (2 ′), and an adhesive When a release sheet is provided on a double-sided pressure-sensitive adhesive sheet comprising a layer or an adhesive layer (6), the double-sided release sheet (4) or the single-sided release sheet (5) (5 ′) is arranged on one or both sides of the double-sided pressure-sensitive adhesive sheet. Is also good.
[0045]
Among the double-sided pressure-sensitive adhesive sheets of the present invention in which the pressure-sensitive adhesive layers (2) and (2 ′) are provided on both sides of the foam sheet (1), the double-sided pressure-sensitive adhesive sheet without the reinforcing sheet (3) is, for example, as follows: Can be obtained 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.
[0046]
[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.
[0047]
[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 ').
[0048]
The double-sided pressure-sensitive adhesive sheet having the above-mentioned 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 pressure-sensitive 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 surface of the pressure-sensitive adhesive layer (6) is covered with a foam sheet ( 1) is laminated. 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 pressure-sensitive 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 surface of the pressure-sensitive adhesive layer (6) is covered with a foam sheet ( 1) is laminated. 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). The pressure-sensitive adhesive layer (6) is laminated on the other surface, then the reinforcing sheet (3) is laminated on the other surface of the pressure-sensitive adhesive layer (6), and the pressure-sensitive adhesive layer is laminated on the other surface of the reinforcing sheet (3). (2 ') is formed, 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 ').
[0049]
As a method of applying each adhesive on the release sheet (4), (5), (5 ′), the foam sheet (1) or the reinforcing sheet (3), for example, a comma coater, a die coater, a lip coater, This is performed using a kiss coater, a gravure coater, or the like. When a comma coater is used, the viscosity of the pressure-sensitive adhesive is preferably about 0.1 to 100 Pa · s.
[0050]
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.
[0051]
Further, the double-sided pressure-sensitive adhesive sheet of the present invention may ² The difference between the maximum thickness and the minimum thickness is 0 to 100 μm, and the water vapor transmission rate is 0 to 1000 g / m. ² It is preferably 24 hours or less.
[0052]
1m of double-sided adhesive sheet 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, when polishing by applying pressure, a pressure difference occurs between the thick part and the thin part. 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, 1m of double-sided adhesive sheet ² The average thickness in the range of 400 μm to 2 μm is used to obtain a desired 25% compression hardness when pressure is applied during polishing, and to resist shear deformation caused by a horizontal shear force on the double-sided pressure-sensitive adhesive sheet. It is preferably 0.5 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.
[0053]
It is important that the 25% compression hardness of the double-sided pressure-sensitive adhesive sheet is from 0.1 to 1.3 MPa, and preferably from 0.15 to 0.7 MPa.
The "25% compression hardness of the double-sided pressure-sensitive adhesive sheet" referred to here is the same as the "25% compression hardness of the foam sheet" in that the double-sided pressure-sensitive adhesive sheet is subjected to the general conditions of the test described in JIS K 6400, ie, a temperature of 23. After standing for 24 hours or more in an environment at 50 ° C. and a relative humidity of 50%, the double-sided pressure-sensitive adhesive sheet was punched into a piece of 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.
[0054]
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 flexible and easily undergoes shearing deformation, so that it becomes difficult to uniformly polish the surface film thickness over the entire surface of the polished body. is there. On the other hand, if the 25% compression hardness exceeds 1.3 MPa, the double-sided pressure-sensitive adhesive sheet tends to be hard. Therefore, a portion having a high altitude is preferentially used without following the “irregularities” and “undulations” on the surface of the object to be polished. Since polishing is performed, it tends to be difficult to uniformly polish the surface thickness of the entire surface of the object to be polished.
[0055]
【Example】
The present invention will be described in detail with reference to examples, but it goes without saying that the present invention is not limited to the following examples.
[0056]
[Creation example 1]
100 parts of polyoxypropylene triol having a molecular weight of 3000, 6 parts of 1,4-butanediol, 0.5 part of an amine catalyst (DABCO) as a catalyst, and a reactive silicone foam stabilizer having terminal OH groups as a silicone foam stabilizer (KF6001) 2.5 parts of water, 0.1 part of water as a foaming agent, and 40 parts of MDI as an isocyanate are mixed and stirred, coated on a release liner and foamed at 100 ° C. for 15 minutes. Heat and 1m ² The average thickness inside is 1502μm, 1m ² The difference between the maximum thickness and the minimum thickness is 30 μm, and the water vapor transmission rate is 63 g / m. ² -A soft polyurethane foam sheet (1-1) having a metal ion content of 12 ppm and a breaking strength of 1.7 MPa was obtained for 24 hours.
[0057]
[Creation example 2]
As in Example 1, 2.5 parts of an NH group-containing reactive silicone foam stabilizer (KF8010; manufactured by Shin-Etsu Chemical Co., Ltd.) was used as a silicone foam stabilizer, and coated on a release liner and foamed. Heat at ℃ for 15 minutes, 1m ² Average thickness of 1568μm, 1m ² The difference between the maximum thickness and the minimum thickness is 74 μm, and the water vapor transmission rate is 61 g / m. ² -A soft polyurethane foam sheet (1-2) having a metal ion content of 14 ppm and a breaking strength of 1.7 MPa was obtained for 24 hours.
[0058]
[Creation example 3]
100 parts of polyoxypropylene triol having a molecular weight of 3000, 6 parts of 1,4-butanediol, 0.2 parts of a tin catalyst (DBTDL) as a catalyst, and non-reactive silicone as a silicone foam stabilizer (F-304; Shin-Etsu Chemical Co., Ltd.) 1.5 parts of water, 0.1 part of water as a foaming agent, and 40 parts of MDI mixed and stirred with a small amount of nitrogen to produce urethane having a large cell diameter. While heating at 100 ° C for 15 minutes while foaming ² The average thickness inside is 1698μm, 1m ² The difference between the maximum thickness and the minimum thickness is 250 μm, and the water vapor transmission rate is 1989 g / m. ² -A soft polyurethane foam sheet (1-3) having a metal ion content of 12000 ppm and a breaking strength of 1.3 MPa was obtained for 24 hours.
[0059]
Embodiment 1
An adhesive composition obtained by stirring and mixing 100 parts of an adhesive containing an adhesive acrylic resin (manufactured by Toyo Ink Mfg. Co., Ltd., metal ion content: 11 ppm) and 3 parts of an isocyanate derivative-based curing agent (manufactured by Toyo Ink Mfg. Co., Ltd.) The coating liquid is applied to the entire surface of a polyethylene terephthalate film (metal ion content: 12 ppm) having a thickness of 75 μm and a breaking strength of 230 MPa to be a reinforcing sheet (3) so as to have a dry film thickness of 30 μm by a comma coater. '), A polyethylene terephthalate release sheet (4), which has been subjected to a double-sided release treatment during winding, is laminated on the pressure-sensitive adhesive layer (2') at a pressure of 0.3 MPa to form a release sheet (4) / adhesive. An adhesive sheet (C) comprising the agent layer (2 ') / the reinforcing sheet layer (3) was obtained.
[0060]
Next, the same pressure-sensitive adhesive composition coating solution as described above is applied to the entire surface of the pressure-sensitive adhesive sheet (C) on the reinforcing sheet (3) side in the same manner so as to have the same dry film thickness, and the pressure-sensitive adhesive layer (6) The flexible polyurethane foam sheet (1-1) produced in Preparation Example 1 was laminated on the pressure-sensitive adhesive layer (6) at the time of winding at a pressure of 0.3 MPa to form a release sheet (4) / adhesive. An adhesive sheet (B) comprising an agent layer (2 ') / a reinforcing sheet layer / an adhesive layer (6) / a foam sheet (1-1) was obtained.
[0061]
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 while forming the pressure-sensitive adhesive layer (2), At the time of winding, after laminating the foam sheet (1-1) side of the pressure-sensitive adhesive sheet (B) 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. 1 m composed of a release sheet (4) / adhesive layer (2 ') / reinforcement sheet (3) / adhesive layer (6) / foam sheet (1-1) / adhesive layer (2) ² The average thickness inside is 1667μm, 1m ² The difference between the maximum thickness and the minimum thickness was 32 µm, and an adhesive sheet (A-1) having a breaking strength of 10 MPa was obtained.
[0062]
Embodiment 2
In the same manner as in Example 1 except that the flexible polyurethane foam sheet (1-2) produced in Preparation Example 2 was used instead of the foam sheet (1-1) used in Example 1, the release sheet ( 4) / Adhesive layer (2 ′) / Reinforcement sheet (3) / Adhesive layer (6) / Foam sheet (1-2) / Adhesive layer (2), similar to the configuration shown in FIG. Configuration, 1m ² The average thickness inside is 1733μm, 1m ² A pressure-sensitive adhesive sheet (A-2) having a difference between a maximum thickness and a minimum thickness of 75 μm and a breaking strength of 10 MPa was obtained.
[0063]
[Comparative Example 1]
In the same manner as in Example 1 except that the flexible polyurethane foam sheet (1-3) produced in Preparation Example 3 was used instead of the foam sheet (1-1) used in Example 1, the release sheet ( 4) / Adhesive layer (2 ′) / Reinforcement sheet (3) / Adhesive layer (6) / Foam sheet (1-3) / Adhesive layer (2), similar to the configuration shown in FIG. Configuration, 1m ² The average thickness inside is 1863μm, 1m ² The difference between the maximum thickness and the minimum thickness was 253 μm, and an adhesive sheet (A-3) having a breaking strength of 9 MPa was obtained.
[0064]
[Comparative Example 2]
Instead of the foam sheet (1-1) used in Example 1, 1 m ² The average thickness is 1289μm, 1m ² The difference between the maximum thickness and the minimum thickness is 310 μm, and the water vapor transmission rate is 4371 g / m. ² -Release sheet (4) / pressure-sensitive adhesive layer (2 ') in the same manner as in Example 1 except that a nonwoven fabric-impregnated polyurethane foam sheet (1-4) having a metal ion content of 181 ppm and a breaking strength of 30 MPa was used for 24 hours. ) / Reinforcement sheet (3) / pressure-sensitive adhesive layer (6) / foam sheet (1-4) / pressure-sensitive adhesive layer (2). ² The average thickness is 1454μm, 1m ² The pressure-sensitive adhesive sheet (A-4) having a difference between the maximum thickness and the minimum thickness of 132 μm and a breaking strength of 28 MPa was obtained.
[0065]
Embodiment 3
An adhesive composition obtained by stirring and mixing 100 parts of an adhesive containing an adhesive acrylic resin (manufactured by Toyo Ink Mfg. Co., Ltd., metal ion content: 11 ppm) and 3 parts of an isocyanate derivative-based curing agent (manufactured by Toyo Ink Mfg. Co., Ltd.) The product 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 (1-1) produced in Preparation Example 1 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 (1-1) was obtained.
[0066]
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), After laminating the pressure-sensitive adhesive sheet (D) 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, and as shown in FIG. 1 m composed of a release sheet (4) / adhesive layer (2 ') / foam sheet (1-1) / adhesive layer (2) ² The average thickness inside is 1565μm, 1m ² The difference between the maximum thickness and the minimum thickness was 33 µm, and an adhesive sheet (E-1) having a breaking strength of 1.6 MPa was obtained.
[0067]
Embodiment 4
Peeling was performed in the same manner as in Example 3 except that the flexible urethane resin foam sheet (1-2) produced in Preparation Example 2 was used instead of the flexible foam sheet (1-1) used in Example 3. It has a structure similar to the structure shown in FIG. 7, comprising sheet (4) / pressure-sensitive adhesive layer (2 ′) / foam sheet (1-6) / pressure-sensitive adhesive layer (2); ² The average thickness inside is 1629μm, 1m ² A pressure-sensitive adhesive sheet (E-2) having a difference between a maximum thickness and a minimum thickness of 75 μm and a breaking strength of 1.6 MPa was obtained.
[0068]
[Comparative Example 3]
Except for using the urethane resin foam sheet (1-3) produced in Preparation Example 3 in place of the foam sheet (1-1) used in Example 3, the release sheet (4) was used in the same manner as in Example 2. ) / Pressure-sensitive adhesive layer (2 ′) / foam sheet (1-3) / pressure-sensitive adhesive layer (2), and has a structure similar to that shown in FIG. ² The average thickness inside is 1863μm, 1m ² The difference between the maximum thickness and the minimum thickness was 252 μm, and an adhesive sheet (E-3) having a breaking strength of 1.6 MPa was obtained.
[0069]
[Comparative Example 4]
Instead of the foam sheet (1-1) used in Example 3, 1 m ² The average thickness is 1289μm, 1m ² The difference between the maximum thickness and the minimum thickness is 310 μm, and the water vapor transmission rate is 4371 g / m. ² -Release sheet (3) / pressure-sensitive adhesive layer (2 ') in the same manner as in Example 2 except that a nonwoven fabric impregnated polyurethane foam sheet (1-4) having a metal ion content of 181 ppm and a breaking strength of 30 MPa was used for 24 hours. / Foam sheet (1-4) / adhesive layer (2), similar to the configuration shown in FIG. ² The average thickness is 1349μm, 1m ² The difference between the maximum thickness and the minimum thickness was 189 μm, and an adhesive sheet (E-4) having a breaking strength of 28 MPa was obtained.
[0070]
[Polishing test]
The adhesive sheet (50 mm × 50 mm) obtained in each of Examples and Comparative Examples was bonded to the adhesive layer (2) side with a water-resistant abrasive paper of No. 1000 specified in JIS R6253, and the adhesive layer (2 ′) side was It was stuck on the surface plate side of a polishing machine manufactured by Tester Sangyo.
On the other hand, the polishing device is mounted on the polishing apparatus such that the convex surface of the following convex polished sample faces a position parallel to the water-resistant polishing paper, and the water-resistant polishing paper and the following convex polished sample are mounted. Contact the sample, load 200gr / cm ² , And polishing was performed for 10 minutes at a speed of 20 m / min while supplying pure water at a flow rate of 20 ml / min. This polishing operation was performed 100 times (about 20 hours for convenience).
[0071]
<Sample to be polished>
60 mm x 300 mm, average thickness 0.130 mm, 60-degree reflective gloss on one side of a 60 mm x 300 mm stainless steel plate (SUS304) with an average thickness of 2.02 mm via an adhesive layer of 0.030 mm thickness The other surface of the polycarbonate sheet (a) having a degree of 14.7 was laminated, and approximately 15 mm × 250 mm, approximately at the center of the polycarbonate sheet (a), with an adhesive layer having a thickness of 0.030 mm interposed therebetween. The other surface of the polycarbonate sheet (b) having a thickness of 0.130 mm and one surface having a 60-degree reflection glossiness of 14.7 is laminated, and the lower portion comprises (a) and the higher portion comprises (b). A convex polishing sample was used.
[0072]
<Evaluation method>
The average thickness of the polycarbonate sheets (a) and (b) of the sample to be polished and the 60-degree reflection gloss were measured before and after polishing, respectively, and the average thickness loss of (b) / (a1) / (a) was averaged. The thickness loss (a1) and the 60-degree reflective gloss (b2) of (b) / 60-degree reflective gloss (a2) of (a) are determined, and (b1) / (a1), (b2) / (a2). ) Was evaluated as follows.

When the difference between the maximum and minimum thicknesses of the double-sided pressure-sensitive adhesive sheet is larger than 100 μm, pressure is not uniformly transmitted to the polycarbonate sheet, and uniform polishing does not proceed. Furthermore, the water vapor transmission rate is 1000 g / m ² -When the time exceeds 24 hours, swelling deformation progresses with the passage of time, causing variations in sheet thickness, and uniform polishing does not progress.
[0073]
[Table 1]

[0074]
【The invention's effect】
The 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, so that the "irregularities" and "undulations" of the object to be polished are processed in a series of steps or at the same time. Can be erased in time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a state in which a double-sided release sheet is laminated on a double-sided pressure-sensitive adhesive sheet of the present invention (with a reinforcing sheet (3)).
FIG. 2 is a cross-sectional view of a state in which a double-sided release sheet is laminated on the double-sided pressure-sensitive adhesive sheet of the present invention (when there is a reinforcing sheet (3)).
FIG. 3 is a cross-sectional view of a state in which a single-sided release sheet is laminated on the double-sided pressure-sensitive adhesive sheet of the present invention (in the case where there is a reinforcing sheet (3)).
FIG. 4 is a cross-sectional view of a state in which a double-sided release sheet is laminated on the double-sided pressure-sensitive adhesive sheet of the present invention (in the case where there is a reinforcing sheet (3), between the reinforcing sheet (3) and the foam sheet (1)). Having a pressure-sensitive adhesive layer or an adhesive layer (6))
FIG. 5 is a cross-sectional view of a state where a double-sided release sheet is laminated on the double-sided pressure-sensitive adhesive sheet of the present invention (in the case where there is a reinforcing sheet (3), between the reinforcing sheet (3) and the foam sheet (1)). Having a pressure-sensitive adhesive layer or an adhesive layer (6))
FIG. 6 is a cross-sectional view of a state in which a single-sided release sheet is laminated on the double-sided pressure-sensitive adhesive sheet of the present invention (in the case where there is a reinforcing sheet (3), and between the reinforcing sheet (3) and the foam sheet (1)). Having a pressure-sensitive adhesive layer or an adhesive layer (6))
FIG. 7 is a cross-sectional view showing a state where a double-sided release sheet is laminated on the double-sided pressure-sensitive adhesive sheet of the present invention (without a reinforcing sheet).
FIG. 8 is a cross-sectional view of a state where a single-sided release sheet is laminated on the double-sided pressure-sensitive adhesive sheet of the present invention (without a reinforcing sheet).
FIG. 9 is a sectional view of an object to be polished;
[Explanation of symbols]
(1) ...... Foam sheet
(2) (2 ') ... adhesive layer
(3) ...... Reinforcement sheet
(4) ……… Double-sided release sheet
(5) (5 ') ... single-sided release sheet
(6) ……… Adhesive layer or adhesive layer

Claims (5)

A double-sided pressure-sensitive adhesive sheet comprising a soft urethane foam sheet and first and second pressure-sensitive adhesive layers,
Said soft urethane foam sheets, the difference between the maximum thickness and the minimum thickness within 1 m ² is within 100μm or more 0 .mu.m, double-sided adhesive vapor transmission rate is less than 0g ^/ m 2 · 24h or more 1000g ^/ m 2 · 24h Sheet. At least one of (1) the metal ion content in the foam sheet and (2) the total metal ion content in the first and second pressure-sensitive adhesive layers is 0.1 ppm or more and 5000 ppm or less. 2. The double-sided pressure-sensitive adhesive sheet according to 1. Further, a double-sided adhesive sheet having a reinforcing sheet,
The double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the reinforcing sheet has a breaking strength of 40 MPa or more and 500 MPa or less, and is provided between any one of the first and second pressure-sensitive adhesive layers and the foam sheet. . The double-sided pressure-sensitive adhesive sheet according to claim 3, wherein the metal ion content in the reinforcing sheet is 0.1 ppm or more and 5000 ppm or less. 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.

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