JP3729584B2 - Semiconductor wafer back surface grinding method and adhesive film used in the method - Google Patents

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【００８８】
実施例７
実施例１の粘着剤塗布液の調整において、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の添加量を０．８重量部とした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は２８０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に破損したウエハは皆無であったが、研削終了後、ウエハと粘着フィルムの間に、水浸入の生じたウエハが１枚観察された。しかし、水浸入の程度は周辺から２ｍｍ未満であり、実用上、殆ど問題にならない程度であった。また、粘着フィルム剥離中に破損したウエハは皆無であった。しかし、表面を水洗した後の半導体シリコンウエハの表面の全チップ数に対して０．４％のチップ（ウエハ周辺付近のチップ）に研削水の浸入に伴うシリコン屑等による若干の汚染が観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表２〕に示す。
【００８９】
実施例８
実施例１の粘着剤塗布液の調整において、アジリジン系架橋剤の代わりにエポキシ系架橋剤〔ナガセ化成工業（株）製、デナコールＥＸ−６１１〕を使用し、添加量を４．８重量部とし、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の添加量を１１．２重量部とした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１１０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に破損したウエハは皆無であり、研削終了後、ウエハと粘着フィルムの間に、水浸入は観察されなかった。粘着フィルム剥離中に破損したウエハも皆無であった。しかし、表面を水洗した後の半導体シリコンウエハの表面の全チップ数に対して０．５％のチップのハイバンプ電極周辺に若干の糊残りが観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表２〕に示す。
【００９０】
実施例９
実施例１の粘着剤塗布液の調整時において、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の代わりに、エチレンオキサイドの共重合率が２５重量％のオキシエチレン−オキシプロピレン共重合体〔グリセリン系、分子量８０００（水酸基価および官能基数より換算）〕を用いた以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１８０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に破損したウエハは皆無であったが、研削終了後、ウエハと粘着フィルムの間に、水浸入の生じたウエハが１枚観察された。しかし、水浸入の程度は周辺から２ｍｍ未満であり、実用上、殆ど問題にならない程度であった。また、粘着フィルム剥離中に破損したウエハは皆無であった。しかし、表面を水洗した後の半導体シリコンウエハの表面の全チップ数に対して０．４％のチップ（ウエハ周辺付近のチップ）に研削水の浸入に伴うシリコン屑等による若干の汚染が観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表２〕に示す。
【００９１】
実施例１０
実施例１の粘着剤塗布液の調整において、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の代わりに、ポリプロピレングリコール〔グリセリン系、分子量３０００（水酸基価および官能基数より換算）〕を使用した以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１８０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に破損したウエハは皆無であり、研削終了後、ウエハと粘着フィルムの間に、水浸入は観察されなかった。粘着フィルム剥離中に破損したウエハも皆無であった。しかし、表面を水洗した後の半導体シリコンウエハの表面の全チップ数に対して０．５％のチップのハイバンプ電極周辺に若干の糊残りが観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表２〕に示す。
【００９２】
実施例１１
実施例１０のポリプロピレングリコールの代わりに、別タイプのポリプロピレングリコール〔グリセリン系、分子量１０００（水酸基価および官能基数より換算）〕を用いた以外は全て実施例１０と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１８０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に破損したウエハは皆無であり、研削終了後、ウエハと粘着フィルムの間に、水浸入は観察されなかった。粘着フィルム剥離中に破損したウエハも皆無であた。しかし、表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して３．０％のチップのハイバンプ電極周辺に若干の糊残りが観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表２〕に示す。
【００９３】
【表２】

【００９４】
比較例１
実施例１の基材フィルムの作製において、ショアーＤ型硬度が３５のエチレン−酢酸ビニル共重合体樹脂の代わりにショアーＤ型硬度が４４のエチレン−酢酸ビニル共重合体樹脂を用い、厚みを３５０μｍとした以外は、全て実施例１と同様の方法で厚みバラツキが１．５％以内の基材フィルムを作製し、粘着剤塗布液の調整において、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の代わりに、エチレンオキサイドの共重合率が１４重量％のオキシエチレン−オキシプロピレン共重合体〔ペンタエリスリトール系、分子量１００００（水酸基価および官能基数より換算）〕を使用し、添加量を７．５重量部とし、粘着フィルムの作製において、乾燥後の粘着剤層の厚みを５０μｍとした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は２３０ｇ／２５ｍｍであった。
実施例１の半導体シリコンウエハの代わりに、５０ｍｍ²の集積回路が周辺まで組み込まれた半導体シリコンウエハ（表面凹凸約５μｍ）の全チップの１０％の表面に対し、高さ７５μｍのインクドットが無作為に着けられたウエハ（直径：６インチ、厚み：６００μｍ）を用いて実施例１と同様の方法で評価した。
研削中に１枚のウエハが破損した。しかし、研削終了後、ウエハと粘着フィルムの間に、水浸入は観察されなかった。粘着フィルム剥離中に破損したウエハも皆無であった。しかし、表面を水洗した後の半導体シリコンウエハの表面を顕微鏡で観察した結果、１０％のチップにマイクロクラックが発生していた。また、粘着剤等による汚染は皆無であった。さらに、裏面研削状況を目視で観察した際に、インクドットに対応する裏面側に、ディンプルが観察された。ディンプルの深さは１５μｍ程度であった。得られた結果を〔表３〕に示す。
【００９５】
比較例２
実施例１の基材フィルムの作製において、厚みを１８０μｍとした以外は、全て実施例１と同様の方法で厚みバラツキが１．５％以内の基材フィルムを作製した以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１８０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に２枚のウエハが破損した。しかし、研削終了後、ウエハと粘着フィルムの間に、水浸入は観察されなかった。粘着フィルム剥離中に破損したウエハも皆無であった。しかし、表面を水洗した後の半導体シリコンウエハの表面を顕微鏡で観察した結果、１５％のチップにマイクロクラックが発生していた。また、粘着剤等による汚染は皆無であった。さらに、裏面研削状況を目視で観察した際に、インクドットに対応する裏面側に、ディンプルが観察された。ディンプルの深さは１５μｍ程度であった。得られた結果を〔表３〕に示す。
【００９６】
比較例３
実施例１の粘着フィルムの作製において、乾燥後の粘着剤層の厚みを２０μｍとした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１２０ｇ／２５ｍｍであった。
実施例１の半導体シリコンウエハの代わりに、高さ４０μｍのハイバンプ電極を有する５０ｍｍ²の集積回路が周辺まで組み込まれた半導体シリコンウエハ（直径：６インチ、厚み：６００μｍ、）を用いて実施例１と同様の方法で評価した。研削中に水侵入が原因で、３枚のウエハが破損した。研削終了後、破損しなかった７枚のウエハに周辺から１．２ｃｍ程度の水浸入が観察された。粘着フィルム剥離中に破損したウエハは皆無であった。表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して２５％のチップ（ウエハ周辺付近のチップ）に研削水の浸入に伴うシリコン屑等による汚染が観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表３〕に示す。
【００９７】
比較例４
実施例１の粘着剤塗布液の調整において、アジリジン系架橋剤の添加量を０．０４重量部とした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は４５０ｇ／２５ｍｍであった。実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に破損したウエハは皆無であり、研削終了後、ウエハと粘着フィルムの間に、水浸入は観察されなかった。粘着フィルム剥離中に３枚のウエハが破損した。表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して２１％のチップのハイバンプ電極周辺に糊残りが観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表３〕に示す。
【００９８】
比較例５
実施例１の基材フィルムの作製において、厚みを３００μｍとした以外は、全て実施例１と同様の方法で厚みバラツキが１．５％以内の基材フィルムを作製し、粘着剤塗布液の調整において、アジリジン系架橋剤の代わりにエポキシ系架橋剤〔ナガセ化成工業（株）製、デナコールＥＸ−６１１〕を使用し、添加量を７．２重量部とし、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の添加量を９．０重量部とした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１１０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に水侵入が原因で２枚のウエハが破損した。研削終了後、破損しなかった８枚のウエハ中、３枚のウエハが、周辺から１ｃｍ程度の水浸入が観察され、５枚のウエハに２ｍｍ未満の水浸入が観察された。粘着フィルム剥離中に破損したウエハは皆無であった。表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して１２％のチップ（ウエハ周辺付近のチップ）に研削水の浸入に伴うシリコン屑等による汚染が観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表３〕に示す。
【００９９】
【表３】

【０１００】
比較例６
実施例１の基材フィルムの作製において、厚みを３００μｍとした以外は、全て実施例１と同様の方法で厚みバラツキが１．５％以内の基材フィルムを作製し、粘着剤塗布液の調整において、アジリジン系架橋剤の添加量を４．８重量部とし、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の添加量を８．０重量部とし、粘着フィルムの作製において、乾燥後の粘着剤層の厚みを３０μｍとした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は７０ｇ／２５ｍｍであった。
実施例１の半導体シリコンウエハの代わりに、実施例３と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に水侵入が原因で１枚のウエハが破損した。研削終了後、破損しなかった９枚のウエハ中、３枚のウエハが、周辺から１ｃｍ程度の水浸入が観察され、６枚のウエハに２ｍｍ未満の水浸入が観察された。粘着フィルム剥離中に破損したウエハは皆無であった。表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して１２％のチップ（ウエハ周辺付近のチップ）に研削水の浸入に伴うシリコン屑等による若干の汚染が観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表４〕に示す。
【０１０１】
比較例７
実施例１の基材フィルムの作製において、厚みを３００μｍとした以外は、全て実施例１と同様の方法で厚みバラツキが１．５％以内の基材フィルムを作製し、粘着剤塗布液の調整において、アジリジン系架橋剤の添加量を４重量部とし、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の添加量を０．２２重量部とした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は２５０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に水侵入が原因で３枚のウエハが破損した。研削終了後、破損しなかった７枚のウエハに周辺から１．２ｃｍ程度の水浸入が観察された。粘着フィルム剥離中に破損したウエハは皆無であった。表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して２３％のチップ（ウエハ周辺付近のチップ）に研削水の浸入に伴うシリコン屑等による汚染が観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表４〕に示す。
【０１０２】
比較例８
実施例１の基材フィルムの作製において、厚みを３００μｍとした以外は、全て実施例１と同様の方法で厚みバラツキが１．５％以内の基材フィルムを作製し、粘着剤塗布液の調整において、アジリジン系架橋剤の代わりにエポキシ系架橋剤〔ナガセ化成工業（株）製、デナコールＥＸ−６１１〕を使用し、添加量を３．６重量部とし、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の添加量を１５重量部とした以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを製造した。得られた粘着フィルムの粘着力は１２０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に破損したウエハは皆無であり、研削終了後、ウエハと粘着フィルムの間に、水浸入は観察されなかった。粘着フィルム剥離中に破損したウエハも皆無であった。しかし、表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して２１％のチップのハイバンプ電極周辺に糊残りが観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表４〕に示す。
【０１０３】
比較例９
粘着剤塗布液の調整において、エチレンオキサイドの共重合率が１５重量％のオキシエチレン−オキシプロピレン共重合体の代わりに、エチレンオキサイドの共重合率が４０重量％のオキシエチレン−オキシプロピレン共重合体〔グリセリン系、分子量６２００（水酸基価および官能基数より換算）〕を使用した以外は全て実施例１と同様の方法で半導体ウエハ裏面研削用粘着フィルムを作製した。得られた粘着フィルムの粘着力は１８０ｇ／２５ｍｍであった。
実施例１と同様の半導体シリコンウエハを用いて実施例１と同様の方法で評価した。研削中に水侵入が原因で１枚のウエハが破損した。研削終了後、破損しなかった９枚のウエハ中、２枚のウエハが、周辺から１ｃｍ程度の水浸入が観察され、７枚のウエハに２ｍｍ未満の水浸入が観察された。粘着フィルム剥離中に破損したウエハは皆無であった。表面を水洗した後の半導体シリコンウエハの表面に、全チップ数に対して９％のチップ（ウエハ周辺付近のチップ）に研削水の浸入に伴うシリコン屑等によるの汚染が観察された。また、裏面研削状況を目視で観察したが、ディンプルは見られなかった。得られた結果を〔表４〕に示す。
【０１０４】
【表４】

【０１０５】
＜実施例の考察＞
〔基材フィルムのショアーＤ型硬度（実施例４、比較例１）〕
基材フィルムのショアーＤ型硬度が４０を超えると、マイクロクラックが発生し、研削中にウエハが破損し、且つ、実用上問題となるレベル（５μｍ以上）のディンプルが発生する。
［基材厚み（実施例６、比較例２）］
基材フィルムの厚みが本発明で限定する下限値の１５０μｍ近くになれば、ディンプルが生じる傾向にある。尚、この場合に生じたディンプルは深さが４μｍ程度である為、通常、実用上は何ら問題ないといわれている。また、基材フィルムの厚み（Ｂ）が本発明で限定する範囲の１８０μｍであるが、ウエハ表面に存在する突起状物の高さ（Ａ）との関係が、４Ａ≦Ｂを満足しないため、ウエハの破損、マイクロクラックを生じる。
〔粘着剤層厚み（実施例１、比較例３）〕
粘着剤層の厚みが本発明で限定する下限値の３０μｍ未満であると、ウエハ表面と粘着剤層の間に水が侵入して、研削中のウエハが破損したり、研削屑によるチップの汚染が生じる。但し、マイクロクラック及びディンプルは発生していない。これに対して、ディンプル及びマイクロクラックの発生、研削時のウエハの破損防止には、基材フィルムの厚み及び硬度が重要な要因となることは前述した通りである。
〔粘着力（比較例６）〕
粘着力が本発明で限定する下限値の８０ｇ／２５ｍｍ未満であると、ウエハ表面と粘着剤層の間に水が侵入して、裏面研削中にウエハが破損したり、研削屑によるチップの汚染が生じる。
［アルキレングリコール系重合体の含有量（実施例７、８、比較例７、８）］
実施例７は、アルキレングリコール系重合体の含有量を本発明で限定する下限値の１重量部近くにした例である。この結果から、アルキレングリコール系重合体の含有量が少ないと粘着力が本願で限定する範囲内であっても、ウエハ表面と粘着剤層の間に水が侵入し易くなる傾向があることがわかる。さらに、含有量が１重量部未満であると、水の侵入により研削中にウエハが破損したり、研削屑等によりチップが汚染される。
【０１０６】
実施例８は、アルキレングリコール系重合体の含有量を本発明で限定する上限の３０重量部近くにした例である。この結果から、実施例８より、アルキレングリコール系重合体の含有量が多いと、チップ上（特にバンプ周辺）に糊残りによる汚染が生じやすくなる傾向があることがわかる。含有量が３０重量部を超えると、チップの汚染が著しくなり、チップの歩留りが著しく低下し、実用上問題が生じる。
〔エチレンオキサイドの共重合率（実施例９、比較例９）〕
アルキレングリコール系重合体中のエチレンオキサイドの共重合率が本発明で限定する上限値の３０重量％近くであると、ウエハ表面と粘着剤層の間に水が侵入し易くなる。エチレンオキサイドの共重合率が３０重量％を超えた場合には、水の侵入により、裏面研削中にウエハが破損したり、研削屑等によりチップが汚染される。
〔アルキレングリコール系重合体の分子量（実施例１０、１１）〕
アルキレングリコール系重合体の分子量が低くなると、汚染が生じ易い傾向を示す。
〔架橋剤の含有量（実施例３、実施例５、比較例４乃至５）〕
架橋剤の含有量が本発明で限定する上限値の１５重量部を超えた場合には、粘着力が本発明で限定する範囲内であっても、ウエハの裏面研削中にウエハ表面と粘着剤層の間に水が侵入して、研削中にウエハが破損したり、研削屑等によりチップが汚染される。架橋剤の含有量が０．５重量部未満であると、チップ上（特にバンプ周辺）に糊残りによる汚染が生じる。さらに、比較例４では粘着力が４００ｇ／２５ｍｍを超えているため、粘着フィルムを剥離する際にウエハの破損が生じている。
【０１０７】
【発明の効果】
本発明によれば、半導体ウエハの裏面を研削するに際し、該半導体ウエハの表面にハイバンプ電極、不良回路識別マーク等の高さが１０〜１００μｍもある突起状物が形成されていても、裏面の研削応力に起因してウエハが破損することがないばかりでなく、チップレベルでの破損（マイクロクラック）を生じることがない。また、粘着フィルムを剥離した後に糊残りがないので、半導体ウエハの表面を汚染することがない上に、突起状物に起因するディンプルの発生もない。さらに、半導体ウエハの表面と粘着剤層の間に水が侵入することに起因するウエハの破損及びウエハ表面の汚染もない。当然のことながら、レジストを用いる必要がなく工程が簡略できるという効果をも奏するものである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for grinding a semiconductor wafer back surface and an adhesive film for grinding a semiconductor wafer back surface used in the method. Specifically, an electrode with a specific height (hereinafter referred to as a high bump electrode) and a defective circuit identification mark (hereinafter referred to as an ink dot) were selected on the surface on which the integrated circuit was incorporated (hereinafter referred to as a wafer surface). The present invention relates to a method for grinding a back surface of a semiconductor wafer that has at least one type of protrusion and is likely to be damaged or contaminated, and an adhesive film for grinding the back surface of a semiconductor wafer used in the method. More specifically, a method of directly bonding an adhesive film to the surface of a semiconductor wafer having the protrusions via an adhesive layer and grinding the other surface of the wafer (hereinafter referred to as the wafer back surface) and The present invention relates to an adhesive film for grinding a semiconductor wafer back surface used in the method.
[0002]
[Prior art]
Usually, a semiconductor integrated circuit is obtained by slicing a high-purity silicon single crystal or the like into a wafer, then incorporating the integrated circuit by ion implantation, etching, etc., and further grinding the back surface of the wafer by grinding, polishing, lapping, etc. It is manufactured by a method of dicing into chips after reducing the thickness to about 100 to 600 μm. During these processes, the semiconductor wafer back grinding adhesive film is attached to the wafer surface via the adhesive layer to prevent damage to the semiconductor wafer during grinding of the wafer back surface and to facilitate grinding. The protection method is used.
[0003]
Specifically, first, an adhesive film for grinding a semiconductor wafer back surface is attached to the wafer surface and the wafer back surface is ground. After the grinding is completed, the film is peeled off and the process proceeds to the next process such as a dicing process.
When trying to grind the back surface of the semiconductor wafer by such a method, there is a problem that if the back surface of the semiconductor wafer having a large surface irregularity is ground, the wafer is damaged due to stress during grinding. Actually, a semiconductor wafer has a coating layer such as polyimide, a deposited film such as a silicon oxide film or a silicon nitride film, a scribe line, etc., and the step may be 50 μm or more.
As means for solving such a problem, Japanese Patent Application Laid-Open No. 61-10242 discloses a wafer processing characterized in that an adhesive is provided on the surface of a base sheet having a Shore D type hardness of 40 or less. A film is disclosed. In the embodiment of the present invention, the backside polishing of a silicon wafer having a surface unevenness difference of 50 μm is actually performed without any problem (without damage).
[0004]
Japanese Patent Laid-Open No. 61-141142 discloses a method in which an adhesive tape made of a rubber material is adhered to the surface of a semiconductor wafer, the tape is cut, and the tape is fixed to a chuck. A method for grinding a semiconductor wafer is disclosed in which the back surface of the semiconductor wafer is ground with a grindstone. In this invention, the back surface grinding of a wafer having a step of about 10 to 80 μm generated by a coating layer made of polyimide or the like on the surface is performed without any particular problem (without damage).
[0005]
Furthermore, WO85 / 05734 discloses a wafer processing film in which an adhesive layer is disposed on one surface of a base film having a Shore D-type hardness of 40 or less. A film for wafer processing is disclosed in which one or more selected from the group consisting of a nonionic surfactant and an ethylene glycol derivative is contained in the pressure-sensitive adhesive layer. Also in the embodiment of the present invention, the backside polishing of a silicon wafer having a surface unevenness difference of 50 μm is actually performed without any problem (without damage). In addition, it is described that post-treatment such as cleaning after peeling off the wafer processing film can be easily performed.
[0006]
The semiconductor wafer disclosed in the above invention has an unevenness of about 50 μm generated on the circuit by a coating layer such as polyimide, a deposited film such as a silicon oxide film or a silicon nitride film, a scribe line, etc. It is. However, only about 10% of the surface of the semiconductor wafer is recessed, and the apex of the convex portion is relatively smooth. Usually, the area of the relatively smooth convex portion occupies about 90% of the wafer surface. The adhesive film described in the said invention is applied to the back surface grinding | polishing of such a semiconductor wafer.
[0007]
In recent years, the surface of semiconductor wafers has been diversifying, and even if the wafer itself is not damaged, the wafer has a surface shape in which damage at the chip level (hereinafter referred to as microcrack) occurs or a part of the adhesive tends to remain. There are many more.
For example, with the thinning of packaging and the reduction of chip mounting area, a wireless bonding method called flip chip mounting is being adopted, and a wafer having a chip suitable for such a wireless bonding method or the like. As a result, semiconductor wafers having protruding high bump electrodes with a height of 10 to 100 μm have been produced. Also, with the diversification of the production process of semiconductor chips, before grinding the back surface of the semiconductor wafer, the chips on the surface of the semiconductor wafer are inspected, and protruding ink dots having a height of 10 to 100 μm are attached to the defective chips. The process of grinding the back surface of the semiconductor wafer is being adopted.
[0008]
When grinding the back surface of a semiconductor wafer having a protrusion having a height of 10 to 100 μm on the surface, such as the above-described high bump electrode and ink dot, the conventional adhesive film as described above cannot sufficiently cope with it. In some cases, depending on various conditions such as the size of the wafer, the thickness after grinding, and the grinding conditions, a microcrack may be generated in a part of the wafer or the wafer may be completely damaged.
[0009]
In addition, even if no damage occurs, the back surface portion corresponding to the protrusion on the front surface is recessed (hereinafter referred to as dimple) due to the influence of the protrusion, and the thickness accuracy of the wafer deteriorates after grinding. This may affect the next process such as dicing, and may cause product defects. Further, when the adhesive film is peeled off from the ground wafer, a part of the adhesive remains on the surface of the wafer (hereinafter referred to as adhesive residue), which may contaminate the wafer surface. It often occurs around the object, and particularly when it occurs around the high bump electrode described later, it becomes a problem. In the case of adhering around the ink dots (on the defective chip), there is practically no problem, but even in this case, it may cause a secondary contamination by moving to another normal part when cleaning the wafer surface. For this reason, it is preferable that there is no contamination]. Although this contamination depends on the degree, even the pressure-sensitive adhesive disclosed in the third invention of the above-mentioned WO85 / 05734 may be insufficiently removed.
Furthermore, during the backside grinding of a semiconductor wafer, water may enter between the wafer surface and the adhesive layer, resulting in damage to the wafer, or grinding waste with water may contaminate the wafer surface. there were.
[0010]
Despite the above-mentioned problems, the technical level of the grinding method is not limited to not only damaging the wafer, but also the chip as the performance of the chip increases, the packaging is diversified, and the cost is reduced. There is a growing demand for the absence of microcracks at the level, further low contamination of the wafer surface, and improved thickness accuracy after grinding.
[0011]
At present, a certain thickness of resist is applied to the surface of the semiconductor wafer, the height of the protrusions is reduced (or the protrusions are completely removed), and an adhesive film is applied to perform backside grinding. Back surface grinding is performed only by resist application, and a rational method such as poor workability of resist application and use of a large amount of solvent at the time of resist application and removal is not always performed. In addition, the resist method may not be applicable to backside grinding of a wafer having ink dots.
Under such circumstances, a rational back grinding method that is particularly suitable for semiconductor wafers having protrusions with a height of 10 to 100 μm, such as high bump electrodes and ink dots, is desired. Yes.
[0012]
[Problems to be solved by the invention]
In view of the above problems, an object of the present invention is to prevent damage to a semiconductor wafer, microcrack, when grinding the back surface of a semiconductor wafer having a protrusion having a height of 10 to 100 μm, such as a high bump electrode and an ink dot. Another object of the present invention is to provide a semiconductor wafer back surface grinding method capable of preventing the occurrence of dimples and preventing contamination of the semiconductor wafer surface, and a back surface grinding adhesive film used in the method.
[0013]
[Means for Solving the Problems]
As a result of intensive studies on an effective method for grinding the back surface of a semiconductor wafer having a specific protrusion on the surface, the present inventors have found that the surface circuit of the semiconductor wafer has a height such as a high bump electrode, an ink dot, etc. Even if a protrusion of 100 μm is formed, the hardness and thickness of the base film, the composition and thickness of the pressure-sensitive adhesive layer, and the adhesive strength of the pressure-sensitive adhesive film are limited to specific ranges, respectively. Adopting an adhesive film in which the three of the thickness (A), the thickness of the base film (B) and the thickness of the adhesive layer (C) are limited to a specific relationship, and affixing it to the circuit forming surface of the semiconductor wafer Thus, the inventors have found that the above object can be achieved, and have reached the present invention.
[0014]
That is, the present invention is a method for grinding a back surface of a semiconductor wafer in which an adhesive film is attached to a circuit forming surface of a semiconductor wafer, the back surface of the semiconductor wafer is ground, and then the adhesive film is peeled off. The forming surface has at least one type of protrusion (A) of 10 to 100 μm selected from electrodes and defective circuit identification marks, and the adhesive film has a Shore D type hardness of 40 or less and a thickness (B) of 150 to (B) 100 parts by weight of an acrylic acid alkyl ester-based pressure-sensitive adhesive polymer having a functional group capable of reacting with a crosslinking agent on one surface of a substrate film having a thickness of 500 μm (provided that 4A ≦ B); 0.5 to 15 parts by weight of a crosslinking agent having two or more crosslinking reactive functional groups, and (c) an alkylene glycol polymer having 3 to 4 carbon atoms of an alkylene group, and ethylene At least one alkylene glycol-based polymer selected from oxyalkylene copolymers having 3 to 4 carbon atoms in an oxyethylene-alkylene group having a copolymerization rate of 30% by weight or less is selected from (a) and (b). ) And a pressure-sensitive adhesive layer having a thickness (C) of 30 to 100 μm (provided that 0.6A ≦ C) is formed, and the pressure-sensitive adhesive film is formed on the SUS304-BA plate. A method for grinding a back surface of a semiconductor wafer, wherein the adhesive strength is 80 to 400 g / 25 mm. Another invention of the present invention is a pressure-sensitive adhesive film for semiconductor wafer back grinding used in the above invention.
[0015]
The characteristics of the present invention are that the hardness and thickness of the base film, the composition and thickness of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive film in which the pressure-sensitive adhesive force of the pressure-sensitive adhesive film is limited to a specific range, and the circuit forming surface of the semiconductor wafer are used. It is to use an adhesive film in which the three of the height (A) of the formed protrusion, the thickness (B) of the base film, and the thickness (C) of the adhesive layer are limited to a specific relationship.
[0016]
According to the present invention, when the back surface of the semiconductor wafer is ground, even if protrusions having a height of 10 to 100 μm such as high bump electrodes and defective circuit identification marks are formed on the surface of the semiconductor wafer, Not only does the wafer not break due to grinding stress, but also breakage at the chip level (microcrack) does not occur. Further, since there is no adhesive residue after the adhesive film is peeled off, the surface of the semiconductor wafer is not contaminated and dimples due to the projections are not generated. Furthermore, there is no wafer breakage and contamination of the wafer surface due to water entering between the surface of the semiconductor wafer and the adhesive layer. As a matter of course, it is not necessary to use a resist, and the process can be simplified.
[0017]
The high bump electrode referred to in the present invention is formed together with a circuit on the surface of a semiconductor wafer as an electrode suitable for mounting a semiconductor chip by a wireless bonding method such as flip chip mounting. Usually, since a semiconductor chip having a high bump electrode is directly connected to the printed wiring board by using this electrode using solder or the like, the electrode has a height of about 10 to 100 μm. A semiconductor wafer having such a high bump electrode exhibits a state (projection) in which only the electrode portion of the circuit protrudes as compared with the conventional one. There are various shapes such as a columnar shape, a prismatic shape, a mushroom shape, etc., depending on the bump forming method, the performance required for the chip, and the like.
[0018]
Further, the ink dot referred to in the present invention is a mark attached on a defective circuit in order to inspect and select a circuit (chip) formed on the surface of the semiconductor wafer and identify the defective circuit. Usually, it is a cylindrical shape colored with a pigment such as red having a diameter of 0.1 to 2 mm and a height of about 10 to 100 μm. The ink dot portion protrudes (protruding object). Projections such as high bump electrodes and ink dots are in a state in which a portion of less than 10% of the total area of the semiconductor wafer surface protrudes to the height. The present invention is applied to a semiconductor wafer having such a surface shape.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the present invention, a pressure-sensitive adhesive film for grinding a back surface of a semiconductor wafer having a pressure-sensitive adhesive layer formed on one surface of a substrate film has a height (A) of at least one selected from high bump electrodes and defective circuit identification marks. It is the method of sticking directly on the surface of a semiconductor wafer which has a projection of -100 micrometers, and performing back surface grinding, and the adhesive film used for the method.
[0020]
The pressure-sensitive adhesive film for back grinding of a semiconductor wafer of the present invention has an alkyl acrylate-based pressure-sensitive adhesive polymer, a cross-linking agent, an alkylene glycol-based polymer, and other additives as required on one surface of a base film or a release film. It is manufactured by applying a solution or emulsion solution containing an agent (hereinafter collectively referred to as an adhesive coating solution) and drying to form an adhesive layer.
[0021]
When forming an adhesive layer on one surface of the substrate film, it is preferable to attach a release film to the surface of the adhesive layer in order to protect it from contamination caused by the environment. Moreover, when forming an adhesive layer on the one surface of a peeling film, the method of transferring an adhesive layer to a base film is taken. Whether to apply the pressure-sensitive adhesive coating solution to one surface of the base film or release film is determined in consideration of the heat resistance of the base film and release film and the contamination of the semiconductor wafer surface. For example, when the heat resistance of the release film is superior to that of the base film, an adhesive layer is provided on the surface of the release film, and then transferred to the base film. When the heat resistance is equivalent or the base film is excellent, an adhesive layer is provided on the surface of the base film, and a release film is attached to the surface.
[0022]
However, considering that the adhesive film for semiconductor wafer backside grinding is stuck to the surface of the semiconductor wafer through the surface of the adhesive layer exposed when the release film is peeled off, the semiconductor wafer surface is contaminated by the adhesive layer. In order to prevent this, a method is preferred in which a release film having good heat resistance is used, and an adhesive coating solution is applied to the surface and dried to form an adhesive layer.
[0023]
As the base film used in the present invention, a base film having a Shore D type hardness of 40 or less is used. The base film having a Shore D type hardness of 40 or less according to the present invention is a film obtained by molding a raw material resin having a Shore D type hardness of 40 or less as defined in ASTM-D-2240 into a film, or It is a film having equivalent performance. When the Shore-D hardness increases, the wafer may be locally damaged at the chip level during back surface grinding (microcrack) or may be completely damaged. Further, there may be a variation in thickness (hereinafter referred to as dimple) such that the back surface corresponding to the protrusion is locally thinned. Wafer damage and micro cracks directly affect the yield of chips, and the occurrence of dimples, depending on the degree, may adversely affect the electrical characteristics of the resulting chip or lead to chip damage in the subsequent dicing process, etc. Sometimes.
[0024]
Examples of the raw material resin having a Shore D type hardness of 40 or less include ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate copolymer resins and derivatives thereof, soft vinyl chloride resins, various synthetic rubbers, and the like. These resins may contain a stabilizer, a lubricant, an antioxidant, a pigment, an antiblocking agent, a plasticizer, and the like as necessary.
[0025]
In addition, as a film having the same performance as a film obtained by molding a raw resin having a Shore D hardness of 40 or less into a film, the raw resin having a Shore D hardness of 40 or less is simply formed into a film. Rather than adding various resins such as plasticizers to films blended with other resins (Shore-D hardness may be outside the scope of the present invention) and resins having Shore-D hardness outside the scope of the present invention. A raw material resin having a Shore D-type hardness of 40 or less as defined in ASTM-D-2240 was formed into a film with a film obtained by mixing and molding an agent and other resins. It has physical properties according to the film. Whether or not it has physical properties according to a film obtained by molding a raw material resin having a Shore D hardness of 40 or less into a film shape is determined by using the elastic modulus of the base film, or hot pressing the base film. It is judged by the measurement result of Shore D type hardness of a sample obtained by laminating and melting without sandwiching air.
[0026]
When various additives such as plasticizers are added to the base film (especially in the case of a soft vinyl chloride resin), the additives migrate to the adhesive layer, changing the properties of the adhesive layer, May be contaminated. In such a case, it is preferable to provide a barrier layer between the base film and the pressure-sensitive adhesive layer.
[0027]
The base film may be a single layer or a laminate. The base film has a thickness (B) of 150 to 500 μm. This is preferably 250 to 500 μm. However, when the height (A) of the protrusion on the surface of the semiconductor wafer is 10 to 100 μm, the thickness (B) and (A) of the base film needs to be in a relationship of 4A ≦ B. is there. If the substrate film becomes thin, microcracks may occur during back surface grinding or it may be completely damaged. In addition, dimples may be generated. When it is thick, it affects the productivity of the base film and leads to an increase in manufacturing costs.
[0028]
The thickness variation of the base film does not significantly affect the local thickness variation (dimple) of the wafer after the back surface grinding, but affects the overall thickness variation. From this point of view, the base film is preferably produced with a thickness variation within a range of about ± 5% of the average thickness. More preferably, it is within ± 3%, and more preferably within ± 2%. The thickness variation referred to here is the variation with respect to the average thickness when a sample of about 10 cm square taken at random is measured every about 1 cm in length and width.
[0029]
Moreover, you may laminate | stack the film harder than this on the surface on the opposite side to the surface in which the adhesive layer of a base film is provided, specifically, the film where Shore D type hardness exceeds 40. Thereby, the rigidity of the pressure-sensitive adhesive film for semiconductor wafer back grinding is increased, and the attaching workability and the peeling workability are improved.
[0030]
In addition, it is excellent in chemical resistance when protecting the surface of the semiconductor wafer by using the adhesive film for grinding the back surface of the semiconductor wafer, also during the etching process with the etching solution applied after grinding the back surface of the semiconductor wafer. It is preferred to use a substrate film. You may laminate | stack a chemical-resistant film on the opposite side to the adhesive layer of a base film. For example, a polypropylene film having excellent chemical resistance is laminated.
[0031]
In order to improve the adhesive force between the base film and the pressure-sensitive adhesive layer, it is preferable to subject the surface of the base film on which the pressure-sensitive adhesive layer is provided to corona discharge treatment or chemical treatment. Moreover, you may use undercoat between a base film and an adhesive layer.
[0032]
The base film of the present invention can be produced by a known technique such as a calendar method, a T-die extrusion method, or an inflation method. Among these, it is preferable to manufacture by a T-die extrusion method in consideration of productivity, thickness accuracy of the obtained film, and the like.
[0033]
Examples of the release film used in the present invention include synthetic resin films such as polypropylene and polyethylene terephthalate. It is preferable that the surface is subjected to silicone treatment or the like as necessary. The thickness of the release film is usually 10 to 2000 μm. Preferably it is 30-100 micrometers.
[0034]
The pressure-sensitive adhesive coating solution used in the present invention is an alkyl acrylate-based pressure-sensitive adhesive polymer, which is a basic component thereof, and a cross-linking having two or more cross-linkable functional groups in one molecule for increasing cohesive force or adjusting adhesive force. Agent or a solution or emulsion containing a specific alkylene glycol polymer.
[0035]
The alkyl acrylate-based pressure-sensitive adhesive polymer used in the present invention is obtained by copolymerizing a monomer mixture containing, as a main monomer, an alkyl acrylate ester and / or an alkyl methacrylate ester, a comonomer having a functional group capable of reacting with a crosslinking agent. It is done.
[0036]
The liquid containing the acrylic acid alkyl ester-based pressure-sensitive adhesive polymer (hereinafter referred to as a pressure-sensitive adhesive main agent) may be any of a solution, an emulsion liquid and the like.
[0037]
Examples of the main monomer include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and the like. These may be used singly or in combination of two or more. The amount of the main monomer used is usually preferably in the range of 60 to 99% by weight in the total amount of all monomers used as the raw material for the pressure-sensitive adhesive polymer.
[0038]
As a comonomer having a functional group capable of reacting with a crosslinking agent to be copolymerized with the main monomer, acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkyl ester, mesaconic acid Monoalkyl ester, citraconic acid monoalkyl ester, fumaric acid monoalkyl ester, maleic acid monoalkyl ester, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, Examples include tertiary-butylaminoethyl methacrylate. One of these may be copolymerized with the main monomer, or two or more may be copolymerized. It is preferable that the usage-amount of the comonomer which has a functional group which can react with said crosslinking agent is normally contained in the range of 1-40 weight% in the total amount of all the monomers used as the raw material of an adhesive polymer.
[0039]
In the present invention, in addition to the main monomer constituting the pressure-sensitive adhesive polymer and the comonomer having a functional group capable of reacting with the crosslinking agent, a specific comonomer having a property as a surfactant (hereinafter referred to as a polymerizable surfactant). May be copolymerized. The polymerizable surfactant has a property of copolymerizing with the main monomer and the comonomer, and also has an action as an emulsifier when emulsion polymerization is performed. In the case of using a pressure-sensitive adhesive polymer that is emulsion-polymerized using a polymerizable surfactant, the surface of the wafer is usually not contaminated by the surfactant. Even when slight contamination caused by the pressure-sensitive adhesive layer occurs, it can be easily removed by washing the wafer surface with water.
[0040]
Examples of such polymerizable surfactants include, for example, those in which a polymerizable 1-propenyl group is introduced into the benzene ring of polyoxyethylene nonylphenyl ether [manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; Aqualon RN-10 RN-20, RN-30, RN-50, etc.], a polymer having a 1-propenyl group introduced into the benzene ring of the ammonium salt of a polyoxyethylene nonylphenyl ether sulfate [Daiichi Kogyo Seiyaku Co., Ltd.] Manufactured by Co., Ltd .; Aqualon HS-10, HS-20, etc.] and sulfosuccinic acid diester type having a polymerizable two bond in the molecule [manufactured by Kao Co., Ltd .; Latemul S-120A, S-180A Etc.].
[0041]
Furthermore, if necessary, a self-crosslinkable functional group such as glycidyl acrylate, glycidyl methacrylate, isocyanate ethyl acrylate, isocyanate ethyl methacrylate, 2- (1-aziridinyl) ethyl acrylate, 2- (1-aziridinyl) ethyl methacrylate, etc. Monomers with polymerizable double bonds such as vinyl acetate, acrylonitrile and styrene, and polyfunctional monomers such as divinylbenzene, vinyl acrylate, vinyl methacrylate, allyl acrylate and allyl methacrylate. Polymerization may be performed.
[0042]
As a method for polymerizing the pressure-sensitive adhesive polymer, various known methods such as a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method can be adopted. However, to the molecular weight of the pressure-sensitive adhesive polymer and the cohesive strength of the pressure-sensitive adhesive. It is necessary to consider the effects of Among these polymerization methods, the emulsion polymerization method is preferable in view of obtaining a high molecular weight polymer, environmental contamination in the coating and drying steps, coating properties, and the like.
[0043]
The polymerization reaction mechanism of the pressure-sensitive adhesive polymer includes radical polymerization, anionic polymerization, cationic polymerization, etc., but the production cost of the pressure-sensitive adhesive, the influence of the functional group of the monomer and the influence of ions on the surface of the semiconductor wafer, etc. are considered. In this case, polymerization is preferably performed by radical polymerization. When polymerizing by radical polymerization reaction, organic compounds such as benzoyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, di-tertiary-butyl peroxide, di-tertiary-amyl peroxide as radical polymerization initiators Inorganic peroxides such as peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 4,4 And azo compounds such as' -azobis-4-cyanovaleric acid.
[0044]
In the case of polymerization by emulsion polymerization method, among these radical polymerization initiators, inorganic peroxides such as water-soluble ammonium persulfate, potassium persulfate, and sodium persulfate, and water-soluble 4,4′-azobis are also used. An azo compound having a carboxyl group in the molecule such as -4-cyanovaleric acid is preferred. Considering the influence of ions on the semiconductor wafer surface, azo compounds having a carboxyl group in the molecule, such as ammonium persulfate and 4,4′-azobis-4-cyanovaleric acid, are more preferable. An azo compound having a carboxyl group in the molecule such as 4,4′-azobis-4-cyanovaleric acid is particularly preferable.
[0045]
The cross-linking agent having two or more cross-linkable functional groups used in the present invention is used to adjust the adhesive force and cohesive force by reacting with the functional group of the pressure-sensitive adhesive polymer. As crosslinking agents, epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, resorcin diglycidyl ether, etc. , Tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane toluene diisocyanate 3 adduct, isocyanate compounds such as polyisocyanate,
[0046]
Trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide) N, N′-hexamethylene-1,6-bis (1-aziridinecarboxamide), N, N′-toluene-2,4-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β- Examples include aziridin compounds such as (2-methylaziridine) propionate and melamine compounds such as hexamethoxymethylolmelamine.
[0047]
These may be used alone or in combination of two or more. Among the above cross-linking agents, epoxy cross-linking agents have a slow cross-linking reaction, and when the reaction does not proceed sufficiently, the cohesive force of the pressure-sensitive adhesive layer becomes low, and depending on the shape of the protrusions on the surface of the semiconductor wafer Contamination due to the agent layer may occur. Therefore, an aziridine-based compound that has a property as an amine when it contains a catalyst such as an amine as appropriate, or a monomer having a catalytic functional amine-based functional group is copolymerized with a pressure-sensitive adhesive polymer or a crosslinking agent is used. It is preferable to use a crosslinking agent in combination.
[0048]
The content of the crosslinking agent is usually within a range in which the number of functional groups in the crosslinking agent does not exceed the number of functional groups in the pressure-sensitive adhesive polymer. However, when a functional group is newly generated by the cross-linking reaction or when the cross-linking reaction is slow, it may be contained excessively as necessary. A preferable content is 0.5 to 15 parts by weight of the crosslinking agent with respect to 100 parts by weight of the pressure-sensitive adhesive polymer. If the amount is small, the cohesive force of the pressure-sensitive adhesive layer becomes insufficient, and adhesive residue tends to occur on the wafer surface (especially around the protrusions), or the adhesive force is outside the scope of the present invention and may become high. If too much, the adhesive force between the pressure-sensitive adhesive layer and the wafer surface becomes weak, and even if the adhesive force to the SUS304-BA plate described later is within the scope of the present application, water and grinding debris enter during grinding, and the adhesive film The wafer may be damaged due to peeling of the wafer, or the wafer surface may be contaminated with grinding dust.
[0049]
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention contains a specific alkylene glycol polymer as an essential component in addition to the above-mentioned alkyl acrylate ester pressure-sensitive adhesive polymer and crosslinking agent. The inclusion of the alkylene glycol-based polymer has an effect of preventing water penetration (hereinafter referred to as water resistance) between the wafer surface and the adhesive layer when grinding the back surface of the wafer having protrusions. In this invention, the adhesive force of an adhesive film is limited to the specific range mentioned later. Although the detailed reason is not clear, within this adhesive force range, there is an effect of improving water resistance during back surface grinding of a wafer surface having a protrusion having a height of 10 to 100 μm.
[0050]
The alkylene glycol polymer as used in the present invention includes those called poly (oxyalkylene) glycol, polyoxyalkylene ether and polyalkylene oxide, and the polymer main chain has a polyether structure. The alkylene glycol polymer is a metal alkoxide, an organic metal compound, an inorganic metal salt, an alkali metal hydroxide, a polyhydric alcohol such as water, alcohols, ethylene glycol, glycerin or pentaesitol. It is synthesized by a method in which a cyclic ether such as ethylene oxide or propylene oxide is subjected to ring-opening addition in the presence of a catalyst such as a 3-amine compound or an acid. Furthermore, it includes a polyether having a structure in which the hydrogen atom of the hydroxyl group at the terminal of the polymer is substituted with an alkyl group [in this case, the molecular weight of the obtained polymer is the molecular weight of the polymer before substitution with the alkyl group (number of hydroxyl groups and functional groups). Estimated from conversion).
[0051]
In the present invention, the alkylene glycol polymer contained in the pressure-sensitive adhesive layer is an alkylene glycol polymer having 3 to 4 carbon atoms in the alkylene group as defined above, and ethylene oxide. It is at least one alkylene glycol polymer selected from the group consisting of oxyalkylene copolymers having a copolymerization rate of 30% by weight or less and an oxyethylene-alkylene group having 3 to 4 carbon atoms. More preferably, the alkylene glycol polymer having 3 to 4 carbon atoms of the alkylene group and the oxyalkylene copolymer having 3 to 4 carbon atoms of the oxyethylene-alkylene group having a copolymerization ratio of ethylene oxide of 20% by weight or less. One or more alkylene glycol polymers selected from the group consisting of polymers.
[0052]
Specifically, polyethers such as homopolymers such as polypropylene glycol, polytrimethylene glycol and polytetramethylene glycol, and copolymers such as oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization ratio of 30% by weight or less Is mentioned. These may be used alone or in combination of two or more. Furthermore, among these, an oxyethylene-oxypropylene copolymer having a copolymerization rate of polypropylene glycol and ethylene oxide of 30% by weight or less is preferable in consideration of production costs and the like. An oxyethylene-oxypropylene copolymer having a copolymerization ratio of polypropylene glycol and ethylene oxide of 20% by weight or less is particularly preferable.
[0053]
In the case of an alkylene glycol polymer having 2 or less carbon atoms in the alkylene group and an oxyethylene-oxyalkylene copolymer having an ethylene oxide copolymerization ratio of more than 30% by weight, the water resistance is lowered and the wafer is being ground. Water may enter between the surface of the semiconductor wafer and the adhesive layer. When water enters between the semiconductor wafer and the pressure-sensitive adhesive layer, the wafer may be damaged or the wafer surface may be contaminated with grinding scraps or the like. Moreover, it becomes difficult to obtain an alkylene glycol polymer having 5 or more carbon atoms in the alkylene group.
[0054]
The average molecular weight of the alkylene glycol polymer contained in the pressure-sensitive adhesive layer is preferably as high as possible in consideration of contamination on the wafer surface. Although there is no restriction | limiting in particular in the preferable upper limit of molecular weight, When molecular weight becomes high, there exists a tendency for manufacture of the alkylene glycol type polymer itself to become difficult. Considering these matters, the average molecular weight is preferably about 2000 to 20000 (converted from the hydroxyl value and the number of functional groups). More preferably, it is 6000-20000.
[0055]
The content of the alkylene glycol polymer is 1 to 30 parts by weight with respect to 100 parts by weight of the sum of the pressure-sensitive adhesive polymer and the crosslinking agent. More preferably, it is 5 to 20 parts by weight. If the content is small, the water resistance is poor, and water tends to enter between the wafer surface and the pressure-sensitive adhesive layer during back surface grinding, and the wafer is liable to be damaged or contaminated by grinding dust on the surface. In addition, if it is large, the wafer surface may be contaminated.
[0056]
In addition to the above-mentioned pressure-sensitive adhesive polymer, cross-linking agent, and alkylene glycol polymer, the pressure-sensitive adhesive coating solution used in the present invention includes rosin-based and terpene resin-based tackifiers, various surfactants, etc. for adjusting the pressure-sensitive adhesive properties. You may contain an agent etc. suitably to such an extent that it does not affect the objective of this invention. When the pressure-sensitive adhesive polymer is an emulsion liquid, a film-forming aid such as diethylene glycol monoalkyl ether may be added as appropriate so as not to affect the object of the present invention. Diethylene glycol monoalkyl ethers and derivatives thereof used as a film-forming aid have the effect of easily removing contamination on the wafer surface caused by the pressure-sensitive adhesive layer, but in the present invention, they are easily contaminated by the pressure-sensitive adhesive layer. Since a semiconductor wafer having protrusions on the surface is used as an adherend, if it is contained in a large amount in the pressure-sensitive adhesive layer, the wafer surface may be contaminated so much that it cannot be cleaned. Therefore, in consideration of these matters, it is preferable to use a material that volatilizes at the drying temperature after coating, and to reduce the residual amount in the pressure-sensitive adhesive layer.
[0057]
The thickness (C) of the pressure-sensitive adhesive layer is 30 to 100 μm. However, a relationship of 0.6A ≦ C needs to be established between the thickness (C) of the pressure-sensitive adhesive layer and the height (A) of the protrusion formed on the surface circuit of the semiconductor wafer. When the thickness of the pressure-sensitive adhesive layer is reduced, the water resistance is poor and water tends to enter between the wafer surface and the pressure-sensitive adhesive layer during backside grinding, and the wafer is liable to be damaged or contaminated by grinding dust on the surface. When the thickness is increased, it may be difficult to produce an adhesive film, or the productivity may be affected and the manufacturing cost may be increased.
[0058]
The adhesive strength of the adhesive film for grinding a wafer back surface of the present invention is 80 to 400 g / 25 mm, preferably 100 to 350 g / 25 mm, when converted to the adhesive strength to a SUS304-BA plate.
[0059]
The above range is adjusted in consideration of the grinding condition of the wafer back surface, the diameter of the wafer, the thickness of the wafer after grinding, and the like. When the adhesive strength is low, water tends to enter between the wafer surface and the adhesive layer during backside grinding, and the wafer is liable to be damaged or contaminated by grinding dust on the surface. On the other hand, if it is too high, peeling trouble may occur with an automatic tape peeling machine at the time of peeling after back grinding, and the peeling workability may be deteriorated or the wafer may be damaged.
[0060]
As a method for applying the adhesive coating solution to one surface of the base film or the release film, conventionally known coating methods such as a roll coater method, a reverse roll coater method, a gravure roll method, a bar coat method, a comma coater method, a die coater, etc. Can be adopted. Although there is no restriction | limiting in particular in the drying conditions of the apply | coated adhesive, Generally, it is preferable to dry for 10 second-10 minutes in the temperature range of 80-200 degreeC. More preferably, it is dried at 80 to 170 ° C. for 15 seconds to 5 minutes.
[0061]
In this invention, in order to apply the thickness of an adhesive layer to 30 micrometers-100 micrometers, you may apply to a multilayer in multiple times as needed.
In order to sufficiently promote the cross-linking reaction between the cross-linking agent and the pressure-sensitive adhesive polymer, the semiconductor wafer back grinding pressure-sensitive adhesive film is heated at 40 to 80 ° C. for about 5 to 300 hours after the drying of the pressure-sensitive adhesive coating liquid is completed. May be.
[0062]
The manufacturing method of the adhesive film for semiconductor wafer back grinding according to the present invention is as described above. From the viewpoint of preventing contamination of the semiconductor wafer surface, the manufacturing environment for all raw materials such as a base film, a release film, and an adhesive main agent is used. The preparation, storage, coating and drying environment of the adhesive coating solution is preferably maintained at a clean level of class 1,000 or less as defined in the US Federal Standard 209b.
[0063]
Next, a method for grinding the back surface of the semiconductor wafer will be described. The semiconductor wafer back surface grinding method of the present invention grinds the back surface of a semiconductor wafer having at least one type of protrusions selected from a high bump electrode having a height (A) of 10 to 100 μm and a defective circuit identification mark on the surface. In this case, there is a feature in that the pressure-sensitive adhesive film for semiconductor wafer back grinding manufactured by the above method is used.
[0064]
Specifically, first, the release film is peeled from the adhesive layer of the adhesive film for semiconductor wafer back surface grinding (hereinafter referred to as an adhesive film), the adhesive layer surface is exposed, and the height ( A) is affixed to the surface of the semiconductor wafer on the side where the integrated circuit having protrusions of 10 to 100 μm is incorporated. Next, the semiconductor wafer is fixed to the chuck table or the like of the grinding machine via the base film layer of the adhesive film, and the back surface of the semiconductor wafer is ground. After the grinding is finished, the adhesive film is peeled off. After the back surface grinding is completed, a chemical etching process may be performed before the adhesive film is peeled off. If necessary, after the adhesive film is peeled off, the surface of the semiconductor wafer is subjected to a cleaning process such as water cleaning or plasma cleaning.
[0065]
In such a back surface grinding operation, the thickness of the semiconductor wafer before grinding is usually 500 μm to 1000 μm, but is usually ground to about 100 μm to 600 μm depending on the type of the semiconductor chip. The thickness of the semiconductor wafer before grinding is appropriately determined depending on the diameter and type of the semiconductor wafer, and the thickness after grinding is appropriately determined depending on the size of the chip to be obtained, the type of circuit, and the like.
[0066]
The operation of adhering the adhesive film to the semiconductor wafer may be performed manually, but is generally performed by an apparatus called an automatic pasting machine to which a roll-shaped adhesive film is attached. As such an automatic pasting machine, for example, there are ATM-1000B manufactured by Takatori Co., Ltd., ATM-1100, STL series manufactured by Teikoku Seiki Co., Ltd., and the like.
As the back surface grinding method, a known grinding method such as a through-feed method or an in-feed method is employed. In each case, the grinding is performed while water is cooled on a semiconductor wafer and a grindstone.
[0067]
After the back grinding, chemical etching is performed as necessary. Chemical etching is an etching solution selected from the group consisting of an acidic aqueous solution composed of a single or mixed solution of hydrofluoric acid, nitric acid, sulfuric acid, acetic acid, and an alkaline aqueous solution such as an aqueous potassium hydroxide solution and an aqueous sodium hydroxide solution. It is performed by a method such as immersing the semiconductor wafer with the adhesive film attached. The etching is performed for the purpose of removing strain generated on the back surface of the semiconductor wafer, further thinning the wafer, removing an oxide film, etc., pretreatment when forming electrodes on the back surface, and the like. The etching solution is appropriately selected according to the above purpose.
[0068]
After the backside grinding and chemical etching are completed, the adhesive film is peeled off from the wafer surface. This series of operations may be performed manually, but is generally performed by a device called an automatic peeling machine. As such an automatic peeling machine, there are ATRM-2000B manufactured by Takatori Co., Ltd., ATRM-2100 manufactured by Takatori Co., Ltd., and STP series manufactured by Teikoku Seiki Co., Ltd.
[0069]
The wafer surface after peeling off the adhesive film is cleaned as necessary. Examples of the cleaning method include wet cleaning such as water cleaning and solvent cleaning, and dry cleaning such as plasma cleaning. In the case of wet cleaning, ultrasonic cleaning may be used in combination. These cleaning methods are appropriately selected depending on the contamination state of the wafer surface.
[0070]
According to the present invention, a semiconductor wafer having projections such as high bump electrodes and ink dots having a height of 10 to 100 μm on the surface, which has been difficult to grind so far, has no such projections. As in the case of grinding the back surface of a conventional wafer, grinding can be performed easily. In addition, when grinding the back surface of the semiconductor wafer having the protrusions on the surface, it is possible not only to damage the wafer but also to cause grinding without causing microcracks. Further, since no resist or the like is used, the process can be simplified. Furthermore, after peeling off the adhesive film from the surface of the semiconductor wafer, the surface of the semiconductor wafer is hardly contaminated by the adhesive layer or contaminated by the intrusion of grinding scraps. There is almost no variation in the thickness of the back surface caused by unevenness on the protrusions such as dimples, or even if it occurs, it can be suppressed to a range where there is no practical problem.
[0071]
The present invention is applied to the back surface grinding of a semiconductor wafer having a protrusion having a height (A) of 10 to 100 μm, and the effect is further remarkable when the height (A) of the protrusion is 25 μm or more. become.
[0072]
The semiconductor wafer to which the adhesive film for semiconductor wafer back grinding and the semiconductor wafer back grinding method using the semiconductor wafer of the present invention can be applied is not only a silicon wafer, but also germanium, gallium-arsenic, gallium-phosphorus, gallium-arsenic-aluminum, etc. A wafer is mentioned.
[0073]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. In all the examples and comparative examples shown below, preparation and application of an adhesive coating solution in an environment maintained at a cleanness of class 1,000 or less as defined in US Federal Standard 209b, and the back surface of a semiconductor silicon wafer Grinding etc. were carried out. The present invention is not limited to these examples. Various characteristic values shown in the examples were measured by the following methods.
[0074]
(1) Adhesive strength (g / 25mm)
All measurements were performed according to JIS Z-0237, except for the conditions specified below. In an atmosphere of 23 ° C., the pressure-sensitive adhesive film obtained in Example or Comparative Example was attached to the surface of a 5 × 20 cm SUS304-BA plate (JIS G-4305 regulation) through the pressure-sensitive adhesive layer. Left for hours. One end of the sample was clamped, the peeling angle was 180 degrees, and the peeling speed was 300 mm / min. The stress at the time of peeling the sample from the surface of the SUS304-BA plate was measured and converted to an adhesive strength of g / 25 mm.
[0075]
(2) Practical evaluation
The semiconductor film of Example or Comparative Example was bonded to the surface of the semiconductor silicon wafer (diameter: 6 inches, thickness: 600 μm), and the semiconductor was cooled with water by using a grinder. The back surface of the silicon wafer was ground to a thickness of about 250 μm. Ten semiconductor silicon wafers were evaluated for each adhesive film.
After the grinding, the damage condition of the semiconductor silicon wafer was evaluated by the number of breakage, and the semiconductor silicon wafer that was not damaged was visually observed whether water entered from the periphery between the surface and the adhesive film. . When water intrusion is observed, the degree of intrusion is less than 2 mm from the periphery of the wafer (not affecting the yield of chips obtained from the wafer), or more than 2 mm from the periphery (obtained from the wafer) (Effects the chip yield), and the evaluation was based on the number of chips generated.
After the observation of water intrusion, the surface protective tape stripper {manufactured by Takatori Co., Ltd., MODEL: ATRM-2000B; used stripping tape: Highland Mark Filament Tape No. The adhesive film was peeled with 897 [manufactured by Sumitomo 3M Co., Ltd.]}.
The damage situation at the time of peeling of the adhesive film was evaluated by the number of damaged sheets.
Further, the surface of the wafer that was not damaged when the adhesive film was peeled was washed with water using a cleaning machine [D-SPIN 629 manufactured by Dainippon Screen Mfg. Co., Ltd.], and then optical microscope [manufactured by Nikon Corporation: OPTIPHOT2 ] Was enlarged to a range of 50 to 1000 times, and the occurrence of microcracks and contamination for each chip were observed and evaluated according to the following criteria.
・ Milocrack rate (%)
[(Number of chips in which microcracks have occurred) / (Number of observed chips)] × 100
・ Contamination rate (%):
[(Number of contaminated chips) / (number of observed chips)] × 100
[0076]
(3) Generation of dimples on the backside of the wafer
The back surface of the wafer after the back surface grinding was visually observed for the presence of dimples having a depth of about 5 μm or more. When dimples were observed, the depth of the dent was measured.
[0077]
Example 1
(Preparation of base film)
An ethylene-vinyl acetate copolymer resin having a Shore D type hardness of 35 was formed into a film having a thickness of 250 μm using a T-die extruder. At this time, the corona treatment was applied to the pressure-sensitive adhesive layer side. The thickness variation of the obtained film was within ± 1.5%.
[0078]
(Polymerization of adhesive main agent)
150 parts by weight of deionized water in a polymerization reactor, 0.5 part by weight of 4,4′-azobis-4-cyanovaleric acid [manufactured by Otsuka Chemical Co., Ltd., trade name: ACVA] as a polymerization initiator, acrylic acid 73.25 parts by weight of butyl, 14 parts by weight of methyl methacrylate, 9 parts by weight of 2-hydroxyethyl methacrylate, 2 parts by weight of methacrylic acid, 1 part by weight of acrylamide, polyoxyethylene nonylphenyl ether (ethylene A compound in which a polymerizable 1-propenyl group is introduced into the benzene ring of an ammonium salt of a sulfate ester (average of the number of moles of oxide added = approximately 20) [Daiichi Kogyo Seiyaku Co., Ltd .: Aqualon HS-20] 0.75 Emulsion polymerization was carried out for 9 hours at 70 ° C. with stirring using parts by weight to obtain an acrylic resin water emulsion. This was neutralized with 14% by weight aqueous ammonia to obtain a pressure-sensitive adhesive polymer emulsion (pressure-sensitive adhesive main agent) having a solid content of 40% by weight.
[0079]
(Adjustment of adhesive coating solution)
100 parts by weight of the obtained pressure-sensitive adhesive main agent emulsion (pressure-sensitive adhesive polymer concentration: 40% by weight) was collected, and further adjusted to pH 9.3 by adding 14% by weight aqueous ammonia. Next, oxyethylene-oxypropylene copolymer having 2 parts by weight of an aziridine-based cross-linking agent [Nippon Shokubai Chemical Co., Ltd., Chemite PZ-33] and an alkylene glycol-based polymer having a copolymerization ratio of ethylene oxide of 15% by weight. [Pentaerythritol-based, molecular weight 8000 (converted from the hydroxyl value and the number of functional groups)] 5 parts by weight and 5 parts by weight of diethylene glycol monobutyl ether were added to obtain an adhesive coating solution.
[0080]
(Preparation of adhesive film)
This pressure-sensitive adhesive coating solution was applied to a polypropylene film (release film, thickness: 50 μm) using a roll coater, and dried at 120 ° C. for 2 minutes to provide a pressure-sensitive adhesive layer having a thickness of 40 μm. The corona-treated surfaces of the aforementioned ethylene-vinyl acetate copolymer film (Shore D-type hardness: 35) were bonded and pressed to transfer the pressure-sensitive adhesive layer. After the transfer, the film was heated at 60 ° C. for 48 hours, and then cooled to room temperature to produce an adhesive film for grinding a semiconductor wafer back surface. The adhesive force of the obtained adhesive film was 180 g / 25 mm.
[0081]
(Evaluation of adhesive film)
The obtained adhesive film is 50 mm having a high bump electrode with a height of 55 μm. ² The semiconductor silicon is attached to the surface (integrated circuit side) of a semiconductor silicon wafer (diameter: 6 inches, thickness: 600 μm) in which the integrated circuit is embedded to the periphery, and cooled with water using a grinder. The back surface of the wafer was ground to a thickness of about 250 μm. The same operation was performed on 10 similar wafers. None of the wafers were damaged during grinding.
No water permeation was observed between the wafer and the adhesive film after grinding. From these 10 wafers, a surface protective tape peeling machine {manufactured by Takatori Co., Ltd., MODEL: ATRM-2000B; The adhesive film was peeled off using 897 [manufactured by Sumitomo 3M Limited]]. None of the wafers were damaged during the peeling of the adhesive film.
The surface of the obtained semiconductor wafer was washed with water using a washing machine (Dainippon Screen Mfg. Co., Ltd .: D-SPIN 629), evaluation of thickness variation of the semiconductor silicon wafer, and contamination of the wafer surface with a microscope Was observed. The wafer surface was not observed to be contaminated with an adhesive or the like. The back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 1].
[0082]
Example 2
In the production of the base film of Example 1, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1 except that the thickness was 450 μm, and the pressure-sensitive adhesive coating solution was adjusted. In this case, instead of an oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization ratio of 15% by weight, an oxyethylene-oxypropylene copolymer having a copolymerization ratio of ethylene oxide of 14% by weight [pentaerythritol, molecular weight 10000 (converted from the hydroxyl value and the number of functional groups)] was used, and the addition amount was 8.0 parts by weight. In the production of the adhesive film, the thickness of the adhesive layer after drying was 60 μm. A pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner. The adhesive force of the obtained adhesive film was 210 g / 25 mm.
Instead of the semiconductor silicon wafer of Example 1, 50 mm ² A wafer (diameter: 6 inches, thickness) with a random ink dot of 90 μm height on the surface of 10% of all chips of a semiconductor silicon wafer (surface irregularities of about 5 μm) with integrated circuits of : 600 μm), and evaluation was performed in the same manner as in Example 1.
None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, contamination with an adhesive or the like was not observed. Dimples were not observed when the back grinding condition was observed visually. The obtained results are shown in [Table 1].
[0083]
Example 3
In the preparation of the pressure-sensitive adhesive coating solution of Example 1, an epoxy crosslinking agent [Nagase Kasei Kogyo Co., Ltd., Denacol EX-611] was used instead of the aziridine crosslinking agent, and the addition amount was 4.8 parts by weight. Polypropylene glycol [glycerin type, molecular weight 6500 (converted from hydroxyl value and number of functional groups)] was used in place of the oxyethylene-oxypropylene copolymer having a copolymerization ratio of 15% by weight of ethylene oxide, and the addition amount was 3 A pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner as in Example 1 except that the content was 0.0 parts by weight. The adhesive force of the obtained adhesive film was 240 g / 25 mm. Instead of the semiconductor silicon wafer of Example 1, 50 mm having a high bump electrode with a height of 30 μm ² Evaluation was performed in the same manner as in Example 1 using a semiconductor silicon wafer (diameter: 6 inches, thickness: 600 μm) in which the integrated circuit of FIG.
None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, contamination with an adhesive or the like was not observed. Dimples were not observed when the back grinding condition was observed visually. The obtained results are shown in [Table 1].
[0084]
Example 4
In the production of the base film of Example 1, an ethylene-vinyl acetate copolymer resin having a Shore D type hardness of 38 was used instead of an ethylene-vinyl acetate copolymer resin having a Shore D type hardness of 35, and the thickness was increased. Except for 350 μm, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1, and in the preparation of the adhesive coating solution, the copolymerization ratio of ethylene oxide was 15% by weight. Instead of the oxyethylene-oxypropylene copolymer, an oxyethylene-oxypropylene copolymer having a copolymerization rate of ethylene oxide of 14% by weight [pentaerythritol, molecular weight 10,000 (converted from the hydroxyl value and the number of functional groups)] is used. The addition amount is 7.5 parts by weight, and in the production of the adhesive film, the thickness of the adhesive layer after drying is 50 μm. In the same manner as in Example 1, a pressure-sensitive adhesive film for semiconductor wafer back grinding was produced. The adhesive force of the obtained adhesive film was 180 g / 25 mm.
Instead of the semiconductor silicon wafer of Example 1, 50 mm ² A wafer (diameter: 6 inches, thickness) in which 75 μm high ink dots are randomly attached to the surface of 10% of all chips of a semiconductor silicon wafer (surface irregularities of about 5 μm) with integrated circuits of : 600 μm), and evaluation was performed in the same manner as in Example 1. None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, contamination with an adhesive or the like was not observed. Dimples were not observed when the back grinding condition was observed visually. The obtained results are shown in [Table 1].
[0085]
Example 5
In the production of the base film of Example 1, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1 except that the thickness was 350 μm, and the pressure-sensitive adhesive coating solution was adjusted. At that time, the addition amount of the aziridine-based crosslinking agent was 0.4 parts by weight, and instead of the oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization rate of 15% by weight, the polymerization rate of ethylene oxide was 14% by weight. Oxyethylene-oxypropylene copolymer [pentaerythritol, molecular weight 10000 (converted from hydroxyl value and number of functional groups)], added in an amount of 7.5 parts by weight. A pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner as in Example 1 except that the thickness of the agent layer was 55 μm. The adhesive force of the obtained adhesive film was 350 g / 25 mm.
Instead of the semiconductor silicon wafer of Example 1, 50 mm having a high bump electrode with a height of 80 μm ² Evaluation was performed in the same manner as in Example 1 using a semiconductor silicon wafer (diameter: 6 inches, thickness: 600 μm) in which the integrated circuit of FIG.
None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film.
On the surface of the semiconductor silicon wafer after the surface was washed with water, contamination with an adhesive or the like was not observed. Dimples were not observed when the back grinding condition was observed visually. The obtained results are shown in [Table 1].
[0086]
Example 6
In the production of the base film of Example 1, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1 except that the thickness was 160 μm, and the pressure-sensitive adhesive coating solution was adjusted. In addition, the addition amount of the aziridine-based crosslinking agent is 1.6 parts by weight, and the copolymerization rate of ethylene oxide is 14% instead of the oxyethylene-oxypropylene copolymer in which the copolymerization rate of ethylene oxide is 15% by weight. % Oxyethylene-oxypropylene copolymer [pentaerythritol, molecular weight 10,000 (converted from hydroxyl value and number of functional groups)], and the addition amount was 8.0 parts by weight. The adhesive film for semiconductor wafer back surface grinding was manufactured by the method. The adhesive force of the obtained adhesive film was 160 g / 25 mm.
Instead of the semiconductor silicon wafer of Example 1, 50 mm ² A semiconductor wafer (diameter: 6 inches, thickness) with a 30-μm height ink dot on the surface of 10% of all chips of a semiconductor silicon wafer (surface irregularities of about 5 μm) with integrated circuits of : 600 μm), and evaluation was performed in the same manner as in Example 1.
None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, contamination with an adhesive or the like was not observed. However, when the backside grinding condition was observed visually, some dimples (locally thin portions) were observed on the backside corresponding to the ink dots. The depth of the dimple was about 4 μm. The obtained results are shown in [Table 1].
[0087]
[Table 1]

[0088]
Example 7
In the preparation of the pressure-sensitive adhesive coating solution of Example 1, everything was the same as Example 1 except that the amount of oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization rate of 15% by weight was 0.8 parts by weight. The adhesive film for semiconductor wafer back surface grinding was manufactured by this method. The adhesive force of the obtained adhesive film was 280 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. None of the wafers were damaged during grinding, but after the grinding, one wafer with water intrusion was observed between the wafer and the adhesive film. However, the degree of water intrusion was less than 2 mm from the periphery, and was practically insignificant. In addition, no wafers were damaged during the peeling of the adhesive film. However, a slight contamination by silicon dust or the like due to the ingress of grinding water is observed on 0.4% of chips (chips near the wafer periphery) with respect to the total number of chips on the surface of the semiconductor silicon wafer after the surface is washed with water. It was. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 2].
[0089]
Example 8
In the preparation of the pressure-sensitive adhesive coating solution of Example 1, an epoxy crosslinking agent [Nagase Kasei Kogyo Co., Ltd., Denacol EX-611] was used instead of the aziridine crosslinking agent, and the addition amount was 4.8 parts by weight. In the same manner as in Example 1, except that the addition amount of the oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization rate of 15% by weight was changed to 11.2 parts by weight, the adhesive film for semiconductor wafer back grinding was prepared. Manufactured. The adhesive force of the obtained adhesive film was 110 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. However, some adhesive residue was observed around the high bump electrodes of 0.5% of the total number of chips on the surface of the semiconductor silicon wafer after the surface was washed with water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 2].
[0090]
Example 9
In preparing the pressure-sensitive adhesive coating solution of Example 1, an oxyethylene copolymer having an ethylene oxide copolymerization rate of 25% by weight was used instead of the oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization rate of 15% by weight. A pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner as in Example 1 except that an oxypropylene copolymer [glycerin-based, molecular weight 8000 (converted from the hydroxyl value and the number of functional groups)] was used. The adhesive force of the obtained adhesive film was 180 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. None of the wafers were damaged during grinding, but one wafer with water ingress was observed between the wafer and the adhesive film after grinding. However, the degree of water intrusion was less than 2 mm from the periphery, and was practically insignificant. Moreover, there was no wafer damaged during peeling of the adhesive film. However, a slight contamination by silicon dust or the like due to the ingress of grinding water is observed on 0.4% of chips (chips near the wafer periphery) with respect to the total number of chips on the surface of the semiconductor silicon wafer after the surface is washed with water. It was. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 2].
[0091]
Example 10
In the preparation of the pressure-sensitive adhesive coating solution of Example 1, instead of an oxyethylene-oxypropylene copolymer having a copolymerization rate of 15% by weight of ethylene oxide, polypropylene glycol [glycerin type, molecular weight 3000 (from hydroxyl value and number of functional groups) Except that was used), a pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner as in Example 1. The adhesive force of the obtained adhesive film was 180 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. However, some adhesive residue was observed around the high bump electrodes of 0.5% of the total number of chips on the surface of the semiconductor silicon wafer after the surface was washed with water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 2].
[0092]
Example 11
For the backside grinding of a semiconductor wafer in the same manner as in Example 10, except that another type of polypropylene glycol [glycerin type, molecular weight 1000 (converted from hydroxyl value and number of functional groups)] was used instead of the polypropylene glycol in Example 10. An adhesive film was produced. The adhesive force of the obtained adhesive film was 180 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. However, some glue residue was observed around the high bump electrode of 3.0% of the total number of chips on the surface of the semiconductor silicon wafer after the surface was washed with water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 2].
[0093]
[Table 2]

[0094]
Comparative Example 1
In the production of the base film of Example 1, an ethylene-vinyl acetate copolymer resin having a Shore D type hardness of 44 was used instead of an ethylene-vinyl acetate copolymer resin having a Shore D type hardness of 35, and the thickness was 350 μm. A base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1, except that the copolymerization ratio of ethylene oxide was 15% by weight in the adjustment of the adhesive coating solution. Instead of the ethylene-oxypropylene copolymer, an oxyethylene-oxypropylene copolymer having a copolymerization ratio of ethylene oxide of 14% by weight [pentaerythritol, molecular weight 10,000 (converted from the hydroxyl value and the number of functional groups)] is used. All additions except that the addition amount is 7.5 parts by weight and the thickness of the adhesive layer after drying is 50 μm in the production of the adhesive film In the same manner as in Example 1, a pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced. The adhesive force of the obtained adhesive film was 230 g / 25 mm.
Instead of the semiconductor silicon wafer of Example 1, 50 mm ² A wafer (diameter: 6 inches, thickness) in which 75 μm high ink dots are randomly attached to the surface of 10% of all chips of a semiconductor silicon wafer (surface irregularities of about 5 μm) with integrated circuits of : 600 μm), and evaluation was performed in the same manner as in Example 1.
One wafer was damaged during grinding. However, no water permeation was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. However, as a result of observing the surface of the semiconductor silicon wafer with a microscope after the surface was washed with water, microcracks were generated in 10% of the chips. In addition, there was no contamination with an adhesive or the like. Furthermore, dimples were observed on the back side corresponding to the ink dots when the back side grinding condition was visually observed. The depth of the dimple was about 15 μm. The obtained results are shown in [Table 3].
[0095]
Comparative Example 2
In the production of the base film of Example 1, all except that the base film having a thickness variation of 1.5% or less was produced in the same manner as in Example 1 except that the thickness was 180 μm. A pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner. The adhesive force of the obtained adhesive film was 180 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. Two wafers were damaged during grinding. However, no water permeation was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. However, as a result of observing the surface of the semiconductor silicon wafer after washing the surface with a microscope, microcracks were generated in 15% of the chips. In addition, there was no contamination with an adhesive or the like. Furthermore, dimples were observed on the back side corresponding to the ink dots when the back side grinding condition was visually observed. The depth of the dimple was about 15 μm. The obtained results are shown in [Table 3].
[0096]
Comparative Example 3
In the production of the pressure-sensitive adhesive film of Example 1, a pressure-sensitive adhesive film for semiconductor wafer back surface grinding was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was 20 μm. The adhesive force of the obtained adhesive film was 120 g / 25 mm.
Instead of the semiconductor silicon wafer of Example 1, 50 mm having a high bump electrode with a height of 40 μm ² Evaluation was performed in the same manner as in Example 1 using a semiconductor silicon wafer (diameter: 6 inches, thickness: 600 μm) in which the integrated circuit of FIG. Three wafers were damaged due to water intrusion during grinding. After grinding, water penetration of about 1.2 cm from the periphery was observed on seven wafers that were not damaged. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, 25% of the total number of chips (chips in the vicinity of the wafer) was contaminated with silicon debris due to the ingress of grinding water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 3].
[0097]
Comparative Example 4
A semiconductor wafer back grinding adhesive film was produced in the same manner as in Example 1 except that the amount of the aziridine crosslinking agent added was 0.04 parts by weight in the adjustment of the adhesive coating solution of Example 1. The adhesive force of the obtained adhesive film was 450 g / 25 mm. Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. Three wafers were damaged during the peeling of the adhesive film. Adhesive residue was observed around the high bump electrodes of 21% of the total number of chips on the surface of the semiconductor silicon wafer after the surface was washed with water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 3].
[0098]
Comparative Example 5
In the production of the base film of Example 1, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1 except that the thickness was set to 300 μm, and the pressure-sensitive adhesive coating solution was adjusted. In this case, an epoxy crosslinking agent [manufactured by Nagase Kasei Kogyo Co., Ltd., Denacol EX-611] is used instead of the aziridine crosslinking agent, the addition amount is 7.2 parts by weight, and the copolymerization ratio of ethylene oxide is 15 weights. A pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner as in Example 1 except that the amount of% oxyethylene-oxypropylene copolymer added was 9.0 parts by weight. The adhesive force of the obtained adhesive film was 110 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. Two wafers were damaged during grinding due to water intrusion. After the completion of grinding, out of the 8 wafers that were not damaged, 3 wafers were observed to enter the water by about 1 cm from the periphery, and 5 wafers were observed to enter less than 2 mm. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, 12% of the total number of chips (chips in the vicinity of the wafer) was contaminated with silicon debris due to the ingress of grinding water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 3].
[0099]
[Table 3]

[0100]
Comparative Example 6
In the production of the base film of Example 1, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1 except that the thickness was set to 300 μm, and the pressure-sensitive adhesive coating solution was adjusted. The amount of the aziridine-based crosslinking agent added was 4.8 parts by weight, the amount of the oxyethylene-oxypropylene copolymer having a copolymerization rate of ethylene oxide of 15% by weight was 8.0 parts by weight, In production, a pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was changed to 30 μm. The adhesive force of the obtained adhesive film was 70 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 3 instead of the semiconductor silicon wafer in Example 1. One wafer was damaged due to water intrusion during grinding. After completion of the grinding, out of 9 wafers that were not damaged, 3 wafers were observed to enter about 1 cm from the periphery, and 6 wafers were observed to enter less than 2 mm. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, a slight contamination due to silicon dust or the like due to the ingress of grinding water was observed on 12% of the chips (chips near the wafer periphery) with respect to the total number of chips. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 4].
[0101]
Comparative Example 7
In the production of the base film of Example 1, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1 except that the thickness was set to 300 μm, and the pressure-sensitive adhesive coating solution was adjusted. In Example 1, except that the addition amount of the aziridine-based crosslinking agent was 4 parts by weight and the addition amount of the oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization ratio of 15% by weight was 0.22 parts by weight. 1 was used to produce an adhesive film for semiconductor wafer back grinding. The adhesive force of the obtained adhesive film was 250 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. Three wafers were damaged during grinding due to water intrusion. After grinding, water penetration of about 1.2 cm from the periphery was observed on seven wafers that were not damaged. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, 23% of the total number of chips (chips in the vicinity of the wafer) was contaminated with silicon debris due to the ingress of grinding water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 4].
[0102]
Comparative Example 8
In the production of the base film of Example 1, a base film having a thickness variation of 1.5% or less was prepared in the same manner as in Example 1 except that the thickness was set to 300 μm, and the pressure-sensitive adhesive coating solution was adjusted. In this case, an epoxy crosslinking agent (Nagase Kasei Kogyo Co., Ltd., Denacol EX-611) was used instead of the aziridine crosslinking agent, the addition amount was 3.6 parts by weight, and the ethylene oxide copolymerization ratio was 15 weights. A pressure-sensitive adhesive film for grinding a semiconductor wafer back surface was produced in the same manner as in Example 1 except that the addition amount of 15% by weight of oxyethylene-oxypropylene copolymer was changed to 15 parts by weight. The adhesive force of the obtained adhesive film was 120 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. None of the wafers were damaged during grinding, and no water intrusion was observed between the wafer and the adhesive film after grinding. None of the wafers were damaged during the peeling of the adhesive film. However, an adhesive residue was observed around the high bump electrode of 21% of the total number of chips on the surface of the semiconductor silicon wafer after the surface was washed with water. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 4].
[0103]
Comparative Example 9
Oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization rate of 40% by weight instead of an oxyethylene-oxypropylene copolymer having an ethylene oxide copolymerization rate of 15% by weight in the preparation of the adhesive coating solution A pressure-sensitive adhesive film for semiconductor wafer back grinding was prepared in the same manner as in Example 1 except that [glycerin-based, molecular weight 6200 (converted from the hydroxyl value and the number of functional groups)] was used. The adhesive force of the obtained adhesive film was 180 g / 25 mm.
Evaluation was performed in the same manner as in Example 1 using the same semiconductor silicon wafer as in Example 1. One wafer was damaged due to water intrusion during grinding. After the grinding, among the 9 wafers that were not damaged, 2 wafers were observed to enter about 1 cm from the periphery, and 7 wafers were observed to enter less than 2 mm. None of the wafers were damaged during the peeling of the adhesive film. On the surface of the semiconductor silicon wafer after the surface was washed with water, contamination of silicon chips or the like due to the ingress of grinding water was observed on 9% of chips (chips near the wafer periphery) with respect to the total number of chips. Further, the back grinding condition was visually observed, but no dimples were observed. The obtained results are shown in [Table 4].
[0104]
[Table 4]

[0105]
<Consideration of Examples>
[Shore D-type hardness of base film (Example 4, Comparative Example 1)]
When the Shore D-type hardness of the base film exceeds 40, microcracks are generated, the wafer is damaged during grinding, and dimples at a level (5 μm or more) that are practically problematic are generated.
[Base Material Thickness (Example 6, Comparative Example 2)]
If the thickness of the base film is close to the lower limit of 150 μm defined in the present invention, dimples tend to occur. Incidentally, since the dimples generated in this case have a depth of about 4 μm, it is usually said that there is no problem in practical use. Moreover, although the thickness (B) of the base film is 180 μm in the range limited by the present invention, the relationship with the height (A) of the protrusions present on the wafer surface does not satisfy 4A ≦ B. Damage to the wafer and microcracks occur.
[Adhesive layer thickness (Example 1, Comparative Example 3)]
When the thickness of the pressure-sensitive adhesive layer is less than the lower limit of 30 μm defined in the present invention, water enters between the wafer surface and the pressure-sensitive adhesive layer, and the wafer being ground may be damaged, or the chips may be contaminated with grinding dust. Occurs. However, microcracks and dimples are not generated. On the other hand, as described above, the thickness and hardness of the base film are important factors for the generation of dimples and microcracks and the prevention of damage to the wafer during grinding.
[Adhesive strength (Comparative Example 6)]
When the adhesive strength is less than the lower limit of 80 g / 25 mm defined in the present invention, water enters between the wafer surface and the pressure-sensitive adhesive layer, the wafer is damaged during backside grinding, or the chips are contaminated by grinding dust. Occurs.
[Contents of alkylene glycol polymer (Examples 7 and 8, Comparative Examples 7 and 8)]
Example 7 is an example in which the content of the alkylene glycol polymer is close to 1 part by weight of the lower limit value defined in the present invention. From this result, it is understood that when the content of the alkylene glycol polymer is small, water tends to easily enter between the wafer surface and the pressure-sensitive adhesive layer even if the adhesive strength is within the range defined in the present application. . Furthermore, if the content is less than 1 part by weight, the wafer is damaged during grinding due to the intrusion of water, or the chips are contaminated with grinding scraps and the like.
[0106]
Example 8 is an example in which the content of the alkylene glycol polymer is close to the upper limit of 30 parts by weight limited in the present invention. From this result, it can be seen from Example 8 that when the content of the alkylene glycol polymer is large, contamination due to adhesive residue tends to occur on the chip (particularly around the bump). When the content exceeds 30 parts by weight, the contamination of the chip becomes significant, the yield of the chip is remarkably lowered, and a practical problem arises.
[Copolymerization rate of ethylene oxide (Example 9, Comparative Example 9)]
If the copolymerization ratio of ethylene oxide in the alkylene glycol polymer is close to 30% by weight of the upper limit defined in the present invention, water easily enters between the wafer surface and the pressure-sensitive adhesive layer. When the copolymerization ratio of ethylene oxide exceeds 30% by weight, the penetration of water damages the wafer during backside grinding or contaminates the chip with grinding dust or the like.
[Molecular weight of alkylene glycol polymer (Examples 10 and 11)]
When the molecular weight of the alkylene glycol polymer becomes low, contamination tends to occur.
[Content of Crosslinking Agent (Example 3, Example 5, Comparative Examples 4 to 5)]
When the content of the crosslinking agent exceeds the upper limit of 15 parts by weight defined in the present invention, even if the adhesive strength is within the range defined by the present invention, the wafer surface and the adhesive during the backside grinding of the wafer. Water enters between the layers, and the wafer is damaged during grinding, or the chips are contaminated by grinding debris. When the content of the crosslinking agent is less than 0.5 parts by weight, contamination due to adhesive residue occurs on the chip (particularly around the bumps). Furthermore, in Comparative Example 4, since the adhesive strength exceeds 400 g / 25 mm, the wafer is damaged when the adhesive film is peeled off.
[0107]
【The invention's effect】
According to the present invention, when the back surface of the semiconductor wafer is ground, even if protrusions having a height of 10 to 100 μm such as high bump electrodes and defective circuit identification marks are formed on the surface of the semiconductor wafer, Not only does the wafer not break due to grinding stress, but also breakage at the chip level (microcrack) does not occur. Further, since there is no adhesive residue after the adhesive film is peeled off, the surface of the semiconductor wafer is not contaminated and dimples due to the projections are not generated. Furthermore, there is no wafer breakage and contamination of the wafer surface due to water entering between the surface of the semiconductor wafer and the adhesive layer. As a matter of course, it is not necessary to use a resist, and the process can be simplified.

Claims (14)

A method of grinding a back surface of a semiconductor wafer by attaching an adhesive film to a circuit forming surface of a semiconductor wafer, grinding the back surface of the semiconductor wafer, and then peeling the adhesive film, wherein the circuit forming surface of the semiconductor wafer has electrodes and defects. It has at least one type of protrusion (H) of 10 to 100 μm selected from circuit identification marks, and the adhesive film has a Shore D type hardness of 40 or less and a thickness (B) of 150 to 500 μm (provided that 4A ≦ (B) 100 parts by weight of an acrylic acid alkyl ester-based pressure-sensitive adhesive polymer having a functional group capable of reacting with a crosslinking agent on one surface of a base film, and (b) two or more crosslinking reactions in one molecule. A copolymerization ratio of 0.5 to 15 parts by weight of a crosslinking agent having a functional functional group, and (c) an alkylene glycol polymer having 3 to 4 carbon atoms of an alkylene group and ethylene oxide. 30 parts by weight or less of at least one alkylene glycol polymer selected from oxyalkylene copolymers having 3 to 4 carbon atoms in an oxyethylene-alkylene group is 100 parts by weight of the sum of (a) and (b) A pressure-sensitive adhesive layer having a thickness (C) of 30 to 100 μm (provided that 0.6A ≦ C) is included, and the pressure-sensitive adhesive strength of the pressure-sensitive adhesive film to the SUS304-BA plate is 80 to 400 g. / 25 mm of semiconductor wafer back surface grinding method 2. The method for grinding a back surface of a semiconductor wafer according to claim 1, wherein the height (A) of the protrusion is 25 to 100 [mu] m. The alkylene glycol-based polymer is at least one polymer selected from polypropylene glycol and an oxyethylene-oxypropylene copolymer having a copolymerization ratio of ethylene oxide of 30% by weight or less. 2. A method for grinding a back surface of a semiconductor wafer according to 1. 2. The method for grinding a back surface of a semiconductor wafer according to claim 1, wherein the oxyalkylene copolymer having 3 to 4 carbon atoms in the oxyethylene-alkylene group has an ethylene oxide copolymerization ratio of 20% by weight or less. 2. The backside grinding method for a semiconductor wafer according to claim 1, wherein the content of the alkylene glycol polymer is 5 to 20 parts by weight. The molecular weight of the alkylene glycol polymer is 2000 to 20000 (converted from the hydroxyl value and the number of functional groups), and the semiconductor wafer back surface grinding method according to any one of claims 1 to 5. The molecular weight of the alkylene glycol polymer is 6000 to 20000 (converted from the hydroxyl value and the number of functional groups), the semiconductor wafer back surface grinding method according to any one of claims 1 to 5. A pressure-sensitive adhesive film for grinding a back surface of a semiconductor wafer, which is affixed to a circuit forming surface when grinding the back surface of a semiconductor wafer, wherein the circuit forming surface of the semiconductor wafer is selected from electrodes and defective circuit identification marks. One surface of a substrate film having a protrusion of 10 to 100 μm in height (A), the adhesive film having a Shore D type hardness of 40 or less and a thickness (B) of 150 to 500 μm (4A ≦ B) (Ii) 100 parts by weight of an acrylic acid alkyl ester pressure-sensitive adhesive polymer having a functional group capable of reacting with a crosslinking agent, and (b) a crosslinking agent having two or more crosslinking reactive functional groups in one molecule. -15 parts by weight, and (iii) an alkylene glycol polymer having 3 to 4 carbon atoms of an alkylene group, and an oxyethylene-alcohol having a copolymerization ratio of ethylene oxide of 30% by weight or less 1 to 30 parts by weight per 100 parts by weight of the sum of (i) and (b) at least one alkylene glycol polymer selected from oxyalkylene copolymers having 3 to 4 carbon atoms in the xylene group, A pressure-sensitive adhesive layer having a thickness (C) of 30 to 100 μm (0.6 A ≦ C) is formed, and the pressure-sensitive adhesive force of the pressure-sensitive adhesive film to the SUS304-BA plate is 80 to 400 g / 25 mm. Adhesive film for backside grinding of semiconductor wafers. 9. The adhesive film for grinding a back surface of a semiconductor wafer according to claim 8, wherein the height (A) of the protrusion is 25 to 100 [mu] m. The alkylene glycol-based polymer is at least one polymer selected from polypropylene glycol and an oxyethylene-oxypropylene copolymer having a copolymerization ratio of ethylene oxide of 30% by weight or less. 8. An adhesive film for grinding a back surface of a semiconductor wafer according to 8. The pressure-sensitive adhesive film for back grinding of a semiconductor wafer according to claim 8, wherein the copolymerization ratio of ethylene oxide of the oxyalkylene copolymer having 3 to 4 carbon atoms of the oxyethylene-alkylene group is 20% by weight or less. . The pressure-sensitive adhesive film for back grinding of a semiconductor wafer according to claim 8, wherein the content of the alkylene glycol polymer is 5 to 20 parts by weight. The molecular weight of the alkylene glycol polymer is 2000 to 20000 (converted from the hydroxyl value and the number of functional groups), The adhesive film for back grinding of a semiconductor wafer according to any one of claims 8 to 12. 13. The adhesive film for back grinding of a semiconductor wafer according to claim 8, wherein the molecular weight of the alkylene glycol polymer is 6000 to 20000 (converted from the hydroxyl value and the number of functional groups).