JP3627932B2 - Manufacturing method of substrate with through electrode - Google Patents

Description

【００３５】
表１の試料は、絶縁性基材にポリイミドとガラス−エポキシ基材を使用した。ポリイミド基材の形状は１００ｍｍ角の正方形で、厚さは１．５ｍｍと３．０ｍｍの２種類とした。ガラス−エポキシ基材の形状は１２０ｍｍ角の正方形で、厚さは１．８ｍｍと２．４ｍｍの２種類とした。貫通孔の形成にはＮＣドリルによるマイクロ孔あけ加工機を使用し、径が２００μｍφと４００μｍφの２種類の貫通孔を形成した。貫通孔は２ｍｍピッチの等間隔で形成し、各条件１０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。導電性ペーストは、バインダー樹脂として、ビスフェノールＡ型エポキシ樹脂（エピコート８２８ 油化シェルエポキシ製）と脂環式エポキシ樹脂（ＳＴ−１０００ 東都化成製）を１：１で混合したものを使用し、硬化剤としてアミンアダクト系硬化剤（ＭＹ−２４ 味の素製）、分散剤としてリン酸エステル（陰イオン界面活性剤“ブライサーフ” 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ０．２ｗｔ％、０．２ｗｔ％添加した。フィラー粉末には平均粒径２．１μｍの球状Ａｇ粒子の粉末を使用し、導電性ペースト比で９０．５ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。混練された導電性ペーストの粘度は、室温におけるＥ型粘度計による測定で、１３００〜１４００Ｐａ・ｓ（回転数は０．５ＲＰＳ）であった。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すｈ、ｈ’が共に１００μｍとなる条件で充填した。導電性ペーストはオーブンを使用して２００℃×６０ｍｉｎの条件で硬化した後、図１ｅ）に示すｗ、ｗ’が共に２０μｍとなる条件で絶縁性基材の両面をラップ加工して貫通電極つき基板を得た。
【００３６】
各条件の貫通電極１０００個について両端の抵抗値を測定した。３．０ｍｍ厚のポリイミド基材と２．４ｍｍのガラス−エポキシ基材を使用した貫通電極つき基板の電極では、体積抵抗率換算で２×１０^−４Ωｃｍ以上の大きい抵抗値を示す電極が全体の７０％以上含まれていた。また、その大半は電気的導通が全く無い電極であり、貫通電極として使用できないために×の評価結果となった。これは絶縁性基材が厚く貫通孔に導電性ペーストが均一充填出来なかったためと考えられる。本発明の実施例である厚さ２ｍｍ以下の貫通電極つき基板では、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認されたので○の評価結果となった。
【００３７】
表２に絶縁性基材の板厚ｔと材質、貫通孔の大きさ、貫通孔の形成方法、導電性ペーストのはみ出し高さｈ、絶縁性基材の加工量を変えた時の、貫通電極の電気抵抗値の評価結果を示す。
【００３８】
表２

【００３９】
表２の試料は、絶縁性基材に純度９６％の焼結アルミナと無アルカリガラス（＃１７３７ コーニング社製）を使用した。アルミナ基材の形状は７５ｍｍφの円盤状で厚さは１．０ｍｍとし、無アルカリガラス基材の形状は１５０ｍｍφの円盤状で厚さは０．７ｍｍとした。アルミナ基材には炭酸ガスレーザーによるレーザー加工機で１５０μｍφの円形の貫通孔を形成し、無アルカリガラス基材にはレジストマスクとショットブラストで２００μｍφの円形の貫通孔を形成した。貫通孔は２ｍｍピッチの等間隔で形成し、各条件１０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。使用した導電性ペーストは、バインダー樹脂として、ビスフェノールＡ型エポキシ樹脂（エピコート８２８ 油化シェルエポキシ製）と脂環式エポキシ樹脂（ＳＴ−１０００東都化成製）を１：１で混合したものを使用し、硬化剤としてアミンアダクト系硬化剤（ＭＹ−２４ 味の素製）、分散剤としてリン酸エステル（陰イオン界面活性剤“ブライサーフ” 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ０．２ｗｔ％、０．２ｗｔ％添加した。フィラー粉末には平均粒径２．１μｍの球状Ａｇ粒子の粉末を使用し、導電性ペースト比で９０．５ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。混練された導電性ペーストの粘度は、室温におけるＥ型粘度計による測定で、１３００〜１４００Ｐａ・ｓ（回転数は０．５ＲＰＳ）であった。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すはみ出し高さｈを変えて充填した。絶縁性基材の裏面側導電性ペーストはみ出し高さｈ’は、スクリーン印刷機のスペーサーを調整することで１００μｍとした。導電性ペーストはオーブンを使用して２００℃×６０ｍｉｎの条件で熱硬化した後、図１ｅ）に示す絶縁性基材の表面加工量ｗを変えてラップ加工して貫通電極つき基板を得た。このとき絶縁性基材の裏面側の加工量ｗ’は、２０μｍとした。
【００４０】
各条件の貫通電極１０００個について両端の抵抗値を測定した。導電性ペーストのはみ出し高さｈが５０μｍ以下の条件と、基材加工量ｗが３μｍ未満の条件では、体積抵抗率換算で２×１０^−４Ωｃｍ以上の大きい抵抗値を示す電極が全体の５０％以上含まれてので×の評価結果となった。これは、導電性ペーストのはみ出し高さｈもしくは基材加工量ｗが小さいために、図２ａ）に示すフィラー粉末濃度が薄い領域３２が電極内部に残り、電極の抵抗値が大きくなったともの考えられる。５０μｍ以上のはみ出し高さｈと、３μｍ以上の基材加工量の両方を兼ね備えた実施例の貫通電極つき基板では、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認されたので○の評価結果となった。
【００４１】
表３に絶縁性基材の板厚ｔと材質、貫通孔の大きさ、貫通孔の形成方法を変えた時の、貫通電極の電気抵抗値の評価結果を示す。
【００４２】
表３

【００４３】
表３の試料は、絶縁性基材に純度９６％の焼結アルミナとポリイミド基材を使用した。アルミナ基材の形状は７５ｍｍφの円盤状で厚さは０．６ｍｍとし、ポリイミド基材の形状は１００ｍｍ角の正方形で厚さは１．５ｍｍとした。絶縁性基材への貫通孔の形成には、アルミナ基材の場合は炭酸ガスレーザーによるレーザー加工機を使用し、ポリイミド基材の場合はパンチによる孔あけ加工機を使用し、円形の貫通孔を形成した。貫通孔は２ｍｍピッチの等間隔で形成し、各条件１０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。導電性ペーストは、バインダー樹脂として、ビスフェノールＡ型エポキシ樹脂（エピコート８２８ 油化シェルエポキシ製）と脂環式エポキシ樹脂（ＳＴ−１０００ 東都化成製）を１：１で混合したものを使用し、硬化剤としてアミンアダクト系硬化剤（ＭＹ−２４ 味の素製）、分散剤としてリン酸エステル（陰イオン界面活性剤“ブライサーフ” 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ０．２ｗｔ％、０．２ｗｔ％添加した。フィラー粉末には平均粒径２．１μｍの球状Ａｇ粒子の粉末を使用し、導電性ペースト比で９０．５ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。混練された導電性ペーストの粘度は、室温におけるＥ型粘度計による測定で、１３００〜１４００Ｐａ・ｓ（回転数０．５ＲＰＳ）であった。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すｈ、ｈ’が共に１００μｍとなる条件で充填した。導電性ペーストはオーブンを使用して２００℃×６０ｍｉｎの条件で硬化した後、図１ｅ）に示すｗ、ｗ’が共に２０μｍとなる条件で絶縁性基材の表面をラップ加工して貫通電極つき基板を得た。
【００４４】
各条件の貫通電極１０００個について両端の抵抗値を測定した。貫通孔の径が１８μｍであるアルミナ基材を使用した基板では、体積抵抗率換算で２×１０^−４Ωｃｍ以上の大きい抵抗値を示す電極が全体の７０％以上含まれていた。また、その大半は電気的導通が全く無い電極であり、貫通電極として使用できないために×の評価結果となった。これは貫通孔の径が小さく導電性ペーストが均一充填出来なかったためと考えられる。また、貫通孔の径が９００μｍのポリイミド基材を使用した基板では、充填直後にペーストが垂れ出してしまった貫通孔があり、安定して導電性ペーストを充填出来なかった。本発明の実施例である貫通孔の径が３０μｍ以上８００μｍ以下の貫通電極つき基板では、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認されたので○の評価結果となった。
【００４５】
表４に導電性ペーストにおけるフィラー粉末の平均粒径、フィラー粉末粒子の形状を変えた時の、貫通電極の電気抵抗値の評価結果と熱サイクル試験結果を示す。
【００４６】
表４

【００４７】
表４の試料は、絶縁性基材に無アルカリガラス（＃１７３７ コーニング社製）を使用した。絶縁性基材の形状は１５０ｍｍφの円盤状で厚さは０．７ｍｍとした。貫通孔の径は２００μｍとし、ガラス基板上にレジストマスクを形成した後、ショットブラストをあてることで円形の貫通孔を形成した。貫通孔は２ｍｍピッチの等間隔で形成し、各条件１０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。導電性ペーストは、バインダー樹脂として、ビスフェノールＦ型エポキシ樹脂（エピコート８０７ 油化シェルエポキシ製）とダイマー酸をグルシジルエステル化したエポキシ樹脂（エポキシ当量４００〜５００ｇ／ｅｑ）を混合したものを使用し、最終的な導電性ペーストの粘度が室温におけるＥ型粘度計による評価で、１２００〜１３００Ｐａ・ｓ（回転数０．５ＲＰＳ）となるように混合比を調整した。硬化剤にはジシアンジアミド（ＤＩＣＹ７ 油化シェルエポキシ製）、分散剤には陰イオン界面活性剤（カチオーゲン 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ１．０ｗｔ％、０．３ｗｔ％添加した。フィラー粉末には表４に示す平均粒径の異なる粉末を使用し、導電性ペースト比で９０．５ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すｈ、ｈ’が共に１００μｍとなる条件で充填した。導電性ペーストはオーブンを使用して２００℃×６０ｍｉｎの条件で硬化した後、図１ｅ）に示すｗ、ｗ’が共に２０μｍとなる条件で絶縁性基材の両表面をラップ加工して貫通電極つき基板を得た。
【００４８】
各条件の貫通電極１０００個について両端の抵抗値を測定した。球状フィラー粉末の平均粒径が１．０μｍ以下およびフレーク状フィラー粉末の平均粒径が３．０μｍ以下の条件では、体積抵抗率換算で２０×１０^−４Ωｃｍ以上の大きい抵抗値を示す電極が全体の７０％以上含まれていた。これは、フィラー粉末粒子が小さいために粒子どうしの接点が増えることによる接触抵抗が増えたためと考えられる。その他の試料では、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認された。
【００４９】
全ての電極で、体積抵抗率換算２×１０^−４Ωｃｍ以下の電気的な導通が良好な抵抗値を示した条件の基板を、−５５℃〜１２５℃各３０分、１０００サイクルの熱サイクル試験に投入したところ、球状フィラー粉末の平均粒径が８．０μｍ以上およびフレーク状フィラー粉末の平均粒径が２０μｍ以下の条件では、熱サイクル試験後の抵抗値上昇が３％と大きくなることが分かった。フィラー粉末粒子が大きいために粒子どうしの接点が少なくなるため、電極の熱サイクルに対する信頼性が低くなっているものと考えられる。本発明の実施例である、球状フィラー粉末の平均粒径が１．０μｍ以上８．０μｍ以下、およびフレーク状フィラー粉末の平均粒径が３．０μｍ以上２０μｍ以下の条件では、全ての電極で電気的な導通が良好な抵抗値を示し、熱サイクル試験後の抵抗値変化も１％以下と良好な値を示したので○の評価結果となった。
【００５０】
表１から表４を用いて説明した様に、導電性ペーストを貫通孔に絶縁性基材の面から高さ５０μｍ以上２００μｍ以下のはみ出し量が発生するように充填し、熱硬化した後導電性ペーストを含む絶縁性基材を、研削もしくはラップで片側５μｍ以上５０μｍ以下加工して、３００μｍ以上２ｍｍ以下の貫通電極つき基板を得ることで、全ての電極で電気的な導通が良好な抵抗値を示し、熱サイクル試験後の抵抗値変化も小さいものが得られるものである。これら本発明の製造条件範囲内で、製作した貫通電極つき基板の実施例を以下に述べる。
【００５１】
本発明の実施例として、セラミックス基材を使用した例を以下に示す。絶縁性基材に純度９６％の焼結アルミナを使用した。絶縁性基材の体積抵抗率は１×１０^１４Ωｃｍである。絶縁性基材は７５ｍｍφの円盤状で厚さは１．０ｍｍとした。貫通孔は炭酸ガスレーザーによるレーザー加工機で形成し、径が１５０μｍφの円形とした。貫通孔は２ｍｍピッチの等間隔で形成し、３０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。導電性ペーストは、バインダー樹脂として、ビスフェノールＡ型エポキシ樹脂（エピコート８２８ 油化シェルエポキシ製）と脂環式エポキシ樹脂（ＳＴ−１０００東都化成製）を１：１で混合したものを使用し、硬化剤としてアミンアダクト系硬化剤（ＭＹ−２４ 味の素製）、分散剤としてリン酸エステル（陰イオン界面活性剤“ブライサーフ” 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ０．２ｗｔ％、０．２ｗｔ％添加した。フィラー粉末には平均粒径２．１μｍの球状Ａｇ粒子の粉末を使用し、導電性ペースト比で９０．５ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。混練された導電性ペーストの粘度は、室温におけるＥ型粘度計による測定で、１３００〜１４００Ｐａ・ｓ（回転数は０．５ＲＰＳ）であった。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すｈ、ｈ’が共に１００μｍとなる条件で充填した。導電性ペーストはオーブンを使用して２００℃×６０ｍｉｎの条件で硬化した後、図１ｅ）に示すｗ、ｗ’が共に２０μｍとなる条件で絶縁性基材表面をラップ加工して、７５ｍｍφ、０．９６ｍｍ厚の貫通電極つき基板を得た。
【００５２】
貫通電極３０００個について両端の抵抗値を測定したところ、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認された。
【００５３】
本発明の他の実施例として、ガラス基材を使用した例を以下に示す。絶縁性基材に無アルカリガラス（＃１７３７ コーニング社製）を使用した。絶縁性基材の体積抵抗率は３×１０^１３Ωｃｍである。絶縁性基材は１５０ｍｍφの円盤状で厚さは０．７ｍｍとした。貫通孔の径は２００μｍとし、ガラス基板上にフォトレジストマスクを形成した後、ショットブラストをあてることで形成した。貫通孔は２ｍｍピッチの等間隔で形成し、３０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。導電性ペーストは、バインダー樹脂として、ビスフェノールＡ型エポキシ樹脂（エピコート８２８ 油化シェルエポキシ製）とアミン型エポキシ樹脂（ＥＬＮ−１２５ 住友化学工業製）を１：１で混合したものを使用し、硬化剤としてアミンアダクト系硬化剤（ＰＮ−２３ 味の素製）、分散剤としてポリオキシエチレンソルビタン脂肪酸エステル（非イオン界面活性剤“ソルゲン”ＴＷ 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ０．３ｗｔ％、０．２ｗｔ％添加した。フィラー粉末には還元法で作製した平均粒径４．９μｍの球状Ｃｕ粒子にＡｇをコーティングした粉末を使用し、導電性ペースト比で９１．０ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。混錬された導電性ペーストの粘度は、室温におけるＥ型粘度計による測定で、１２００〜１３００Ｐａ・ｓ（回転数は０．５ＲＰＳ）であった。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すｈ、ｈ’が共に１００μｍとなる条件で充填した。導電性ペーストはオーブンを使用して１８０℃×６０ｍｉｎの条件で硬化した後、図１ｅ）に示すｗ、ｗ’が共に２０μｍとなる条件で絶縁性基材表面をラップ加工して、１５０ｍｍφ、０．６６ｍｍ厚の貫通電極つき基板を得た。
【００５４】
貫通電極３０００個について両端の抵抗値を測定したところ、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認された。
【００５５】
本発明の他の実施例として、絶縁性基材にポリイミドを使用した例を以下に示す。絶縁性基材の体積抵抗率は１×１０^１６Ωｃｍである。絶縁性基材は１００ｍｍ角の正方形で厚さは０．５ｍｍとした。貫通孔はパンチによる孔あけ加工機で形成し、短径１３０μｍ、長径１８０μｍの楕円形とした。貫通孔は２ｍｍピッチの等間隔で形成し、３０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。導電性ペーストは、バインダー樹脂として、ビスフェノールＦ型エポキシ樹脂（エピコート８０７ 油化シェルエポキシ製）とダイマー酸をグルシジルエステル化したエポキシ樹脂（エポキシ当量４００〜５００ｇ／ｅｑ）を１：３で混合したものを使用し、硬化剤としてジシアンジアミド（ＤＩＣＹ７ 油化シェルエポキシ製）、分散剤として陰イオン界面活性剤（カチオーゲン 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ１．０ｗｔ％、０．３ｗｔ％添加した。フィラー粉末には平均粒径１０．５μｍのフレーク状Ａｇ粒子の粉末を使用し、導電性ペースト比で９０．３ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。混練された導電性ペーストの粘度は、室温におけるＥ型粘度計による測定で、１３００〜１４００Ｐａ・ｓ（回転数０．５ＲＰＳ）であった。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すｈ、ｈ’が共に１００μｍとなる条件で充填した。導電性ペーストはオーブンを使用して２００℃×６０ｍｉｎの条件で硬化した後、図１ｅ）に示すｗ、ｗ’が共に２０μｍとなる条件で絶縁性基材表面をラップ加工して、１００ｍｍ角、０．４６ｍｍ厚の貫通電極つき基板を得た。
【００５６】
貫通電極３０００個について両端の抵抗値を測定したところ、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認された。
【００５７】
本発明の他の実施例として、絶縁性基材にガラス−エポキシ基材を使用した例を以下に示す。絶縁性基材は２００μｍ厚のアラミド不織布エポキシシートを６枚重ねたものであり、絶縁性基材の体積抵抗率は２×１０^１０Ωｃｍである。絶縁性基材は１２０ｍｍ角の正方形で、厚さは１．２ｍｍとした。貫通孔はＮＣドリルによるマイクロ孔あけ加工機で形成し、径は２５０μｍφの円形とした。貫通孔は２ｍｍピッチの等間隔で形成し、３０００個の貫通孔に電極が形成されるよう基材枚数を用意し、貫通電極つき基板を作製した。導電性ペーストは、バインダー樹脂として、ビスフェノールＡ型エポキシ樹脂（エピコート８２８ 油化シェルエポキシ製）とダイマー酸をグルシジルエステル化したエポキシ樹脂（エポキシ当量４００〜５００ｇ／ｅｑ）を１：１で混合したものを使用し、硬化剤として無水フタル酸、分散剤としてリン酸エステル（陰イオン界面活性剤“ブライサーフ” 第一工業製薬製）を使用した。硬化剤と分散剤は、導電性ペースト比でそれぞれ２．８ｗｔ％、０．２ｗｔ％添加した。フィラー粉末には平均粒径１．５μｍの球状Ａｇ粒子と平均粒径１１．２μｍのフレーク状Ａｇ粒子を４：６で混合した粉末を使用し、導電性ペースト比で８９．７ｗｔ％添加した。これらバインダー樹脂とフィラー粉末は三本ロールで脱泡しながら攪拌、混練した。混練された導電性ペーストの粘度は、室温におけるＥ型粘度計による測定で、１２００〜１３００Ｐａ・ｓ（回転数は０．５ＲＰＳ）であった。貫通孔への導電性ペーストの充填はスクリーン印刷機を使用し、図１ｄ）に示すｈ、ｈ’が共に１００μｍとなる条件で充填した。導電性ペーストはオーブンを使用して２００℃×６０ｍｉｎの条件で硬化した後、図１ｅ）に示すｗ、ｗ’が共に３０μｍとなる条件で絶縁性基材表面をラップ加工して、１２０ｍｍ角、１．１４ｍｍ厚の貫通電極つき基板を得た。
【００５８】
貫通電極３０００個について両端の抵抗値を測定したところ、全ての電極が体積抵抗率換算で２×１０^−４Ωｃｍ以下の抵抗値を示し、電気的導通が良好な貫通電極が形成されていることが確認された。
【００５９】
【発明の効果】
絶縁性基材に形成した貫通孔に樹脂硬化型の導電性ペーストを充填し、エポキシ系樹脂の硬化温度に予め加熱したオーブンに基板を入れて、基板の初期加熱時に基板表面と基板内部に温度差を生じさせてエポキシ系樹脂を硬化させ、基板厚中央部にフィラー濃度の濃い領域を形成し、基板両表面端近傍にフィラー濃度の薄い領域を形成する。熱硬化後に導電性ペーストのフィラー濃度の薄い領域と絶縁性基板表面を同時に機械加工する。フィラー粉末濃度を上げるための特別な装置を必要としない容易な方法で、電気的導通に優れた電極を安定的に得ることが可能な、絶縁性基材面と導電性ペースト面が同一な貫通電極つき基板を製造する方法を提供できた。
以 上
【図面の簡単な説明】
【図１】本発明の工程フローを示す基板断面図である。
【図２】従来の貫通電極のフィラー粉末濃度分布を示す断面図である。
【図３】フィラー粉末濃度が薄い領域の形成を説明する図である。
【符号の説明】
１ 絶縁性基材、２ 貫通孔、３ 導電性ペースト、４ 貫通電極つき基板、３０ 硬化前の導電性ペースト、３１ 表層、
３２ 硬化後フィラー粉末濃度が薄い領域、３３ 内部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a substrate with a through electrode, which can stably obtain an electrode excellent in electrical conduction.
[0002]
[Prior art]
When taking out an electrode from a sensor chip manufactured by using a wafer process, ultrasonic bonding of metal wires, solder bonding of a patterned flexible cable, and the like have been generally used. When manufacturing a sensor chip, if a substrate with a through electrode can be applied, the electrode can be taken from the back of the sensor chip, eliminating the need for an electrode pad on the sensor chip surface (circuit surface) side, and reducing the sensor chip size. Can be realized. In addition, since no wires or flexible cables are arranged on the surface side of the sensor chip and the surface of the sensor chip can be brought close to the sensing target, it is possible to improve the sensitivity of the sensor. Furthermore, if the sensing target is a flat surface, the sensor can be slid. By using the wafer process, the sensor pattern can be miniaturized and miniaturized by photolithography, and the cost can be reduced by batch production of sensor chips. From the above merits, it can be said that the substrate with the through electrode is a very useful substrate for the production of the sensor chip.
[0003]
The method of manufacturing a substrate with a through electrode is a method of manufacturing a substrate by applying an insulating base material to a previously formed electrode, focusing on the electrodes and the insulating base material constituting the substrate, and the electrode and the insulating base material. Three methods are conceivable: a method of forming a substrate by forming simultaneously, and a method of manufacturing a substrate by applying an electrode to an insulating base formed in advance.
[0004]
As a method of manufacturing a substrate by applying an insulating base material to a previously formed electrode, a method in which a thin wire electrode is arranged in advance and an insulating base material is solidified so as to surround it can be considered. The thin wire-like substance serving as the electrode may be a conductive substance such as metal, and the insulating substrate may be an insulating substance such as ceramics, glass, or resin. For the solidified formation of the insulating base material, methods such as pouring into a mold, injection molding, and sintering can be considered depending on the selection of the insulating base material. However, with the method shown here as an example, it is difficult not only to arrange the fine wire electrodes with high precision, but also to maintain the position accuracy of the thin wire electrodes with heat and pressure during the formation of the insulating substrate. Is difficult. In order to make use of the advantages of the photolithography technology, it is necessary to dispose high-precision and fine electrodes. Therefore, it is difficult to say that this method is suitable for manufacturing a substrate with a through electrode.
[0005]
As a method for forming a substrate by simultaneously forming an electrode and an insulating base material, a method for producing a laminated ceramic can be considered. This is a method in which several ceramic sheets on which through electrode patterns of conductive paste are arranged are stacked and sintered. However, in this method, it is necessary to superimpose many thin sheets when forming the substrate. Since the shrinkage at the time of sintering the substrate is large, it is difficult to arrange the electrodes with high accuracy. Therefore, it cannot be said that this method is also suitable for producing a substrate with a through electrode.
[0006]
As a method for producing a substrate by applying an electrode to an insulating base material, there is a method of forming a through hole in the insulating base material, filling the through hole with a conductive paste, and curing to obtain a substrate with a through electrode. is there. The insulating substrate may be an insulator such as ceramics, glass, or resin, and the conductive paste may be selected from a material that cures within the heat resistant temperature of the insulating substrate material. A screen printing technique can be used for filling the conductive paste, and it is possible to fill the through holes formed in the insulating base material in a lump. Since the electrode placement accuracy is determined by the processing accuracy of through-hole formation, if a method for forming fine through-holes with high accuracy is selected, it is possible to produce a substrate with through-electrodes with fine electrodes arranged with high accuracy. is there. As a method of forming an electrode in the through hole, there is a method of fitting a metal that is easily plastically deformed into the through hole, but it is desirable because there is a risk that the insulating base material is broken by the force when the metal is fitted. It's not a method. There is also a method of filling the through holes with metal by plating. However, since the base material is an insulator, it is necessary to form a plating seed layer by some method, and this is not a desirable method because the process tends to be complicated. It can be said that the method of forming an electrode by filling an insulating base material having a through hole with a conductive paste is an effective method for easily producing a substrate with a through electrode.
[0007]
The conductive paste is composed of conductive powder particles called a filler and a liquid binder called a binder. By selecting an appropriate component for the binder, the curing temperature of the conductive paste can be set to a necessary temperature. Conductive paste used for electrode formation of laminated ceramic parts, etc. uses a glass component as a binder, and therefore requires baking at around 900 ° C. for curing, but resin curing using a thermosetting resin such as epoxy as a binder The mold type conductive paste can be cured at a temperature of about 200 ° C. If a resin curable conductive paste is used, the conductive paste can be cured with a simple device such as an oven, and even a material having a low heat-resistant temperature can be used as an insulating substrate.
[0008]
[Problems to be solved by the invention]
The inventors have made various plate-like substrates having through-holes.(Hereafter, the base material may be referred to as a substrate)A resin curable conductive paste (hereinafter simply referred to as a conductive paste) was filled and cured, and a substrate with through electrodes was prepared. A screen printing method was used for filling the conductive paste, and the through holes were filled with the conductive paste without excess or deficiency. A batch-type oven heated in advance was used for curing the conductive paste. When the resistance value at both ends of the electrode was examined after the substrate with through electrodes was completed, it was found that there were many conductive defects. Considering the fact that the filler powder particles on the outermost layer of the conductive paste were oxidized, the surface of the substrate was lightly lapped by several μm and remeasured, but there was no significant change in the frequency of occurrence of poorly conductive electrodes.
[0009]
Detailed observation of poorly conductive electrodes,It was found that the filler powder concentration distribution in the cross section of the through electrode is characteristic. FIG. 2 a) shows a cross section of the through electrode portion filled and cured with the conductive paste. It turned out that the area | region 32 where the filler powder density | concentration is thin compared with the surface layer 31 and the inside 33 is formed in both surfaces of the insulating base material 1 in the part of a certain depth from the surface of the electrically conductive paste 3. FIG. As shown in FIG. 2 b), even when the surface layer 31 was lightly removed by lapping, a region 32 having a low filler powder concentration was present in the conductive paste 3..From this, it is estimated that generation | occurrence | production of a poor conduction electrode originates in the area | region 32 where the filler powder density | concentration demonstrated in FIG. 2 is thin..
[0010]
The binder resin of conductive paste has a larger coefficient of thermal expansion than filler powder particles.,Since it is rich in fluidity, it has the property of easily exuding from the inside of the conductive paste to the outside during thermosetting. In addition, the filler powder particles tend to aggregate each other at the time of thermosetting, and the bleeding of the binder resin is easily promoted. Furthermore, when the plate thickness t of the insulating base material 1 is increased, the heat conduction is likely to be uneven, and the surface layer 31 of the conductive paste 3 is likely to be hardened first. The above points are presumed to be a factor for forming the region 32 with a low filler powder concentration.
[0011]
The pattern in which the area | region 32 with a low filler powder density | concentration is formed is demonstrated using FIG. The conductive paste 30 before curing immediately after filling the through holes of the insulating substrate 1 shown in FIG.Preheated to the curing temperature of the epoxy resinCuring begins upon exposure to oven heat.HoweverUp to inside of conductive paste 30ImmediatelyHeatBecause it is difficult to communicateFirst, a surface layer (initially cured layer) 31 shown in FIG. 3b) by direct radiant heat (dashed arrow) from the oven.Rapidly formed. When the surface layer 31 is formed, the binder resin does not bleed out due to thermal expansion, and it is presumed that the curing is completed with the ratio of the filler powder and the binder resin almost filled at the time of filling. As the heating of the insulating substrate 1 proceeds, heat (solid arrow) is applied to the conductive paste 30 through the side wall of the through hole, and curing also starts inside the paste. However, since the inside of the conductive paste 30 is slowly cured by conduction heat, the curing is completed while the binder resin expanded by heat oozes out to the interface with the surface layer 31, and as a result, as shown in FIG. 3c). Region 32 where the filler powder concentration is lowFormIt is guessed. In the region 32 where the filler powder concentration is low, the number of contacts of the filler powder particles is small, so that the current path becomes thin and the resistance value increases. Depending on the filler powder concentration in the region 32 where the filler powder concentration is low, it is considered that the cured conductive paste, that is, the through electrode, becomes a poor conduction electrode.
[0012]
Filler powder concentrationThin areaAvoid formingThe method is described in Patent Document 1.,A method of filling a through-hole with a conductive paste and simultaneously pressing with a roll or the likeetcis there. Immediately after filling the conductive paste, roll pressure increases the filler powder concentration in the through hole..However, in order to adopt such a method, a special device as shown in the publication is required, and it can be said that it is difficult to adopt it easily.
[0013]
[Patent Document 1]
JP 2001-160684 (FIGS. 1, 3 to 6)
[0014]
In view of the above problems, the present inventionSpecial to increase filler powder concentrationIt is an object of the present invention to provide a method for manufacturing a substrate with a through electrode that does not require an apparatus and does not generate a poorly conductive electrode. That is, filling a through-hole formed in the insulating base material with a resin-curable conductive paste,The substrate is put in an oven preheated to the curing temperature of the epoxy resin in the conductive paste, and the epoxy resin is cured by causing a temperature difference between the substrate surface and the substrate during the initial heating of the substrate. By curing in a state where a temperature difference has occurred during initial heating of the substrate, a region having a high filler concentration is formed in the central portion of the substrate thickness, and a region having a low filler concentration is formed in the vicinity of both surface edges of the substrate.Conductive paste after thermosettingArea with low filler concentrationAnd insulating substrate surfaceat the same timeInsulated by machiningThe base material surface and the conductive paste surface are the same,An object of the present invention is to provide a method for manufacturing a substrate with a through electrode, which can stably obtain an electrode excellent in electrical conduction.
[0015]
[Means for Solving the Problems]
In the method for producing a substrate with a through electrode in the present invention,A plurality of through holes are formed in an insulating base material made of ceramics, glass, resin or a composite material thereof by laser, shot blasting, punching, drilling, etching, etc., and a curing temperature of 180 ° C. or higher and 200 ° C. or lower is formed in the through holes. A conductive paste prepared by kneading a filler composed of conductive powder particles having an average particle size of 1.0 μm or more and 20 μm or less into an epoxy resin is filled in through holes, and the conductive paste is 50 μm or more and 200 μm or less from both sides of the substrate. After a convex shape is formed at a height, the substrate at room temperature is placed in an oven preheated to the curing temperature of the epoxy resin, and the epoxy resin is cured by causing a temperature difference between the substrate surface and the substrate during the initial heating of the substrate. By filling the both ends near the substrate surface with a thin, high-resistance region of the conductive paste filler powder concentration, the filler powder concentration of the conductive paste A thick low resistance region is formed inside the substrate and a region where the resistance value of the cured conductive paste is different, and the high resistance region at the edge of the substrate is removed by grinding or polishing at 3 μm or more and 50 μm or less on one side simultaneously with the substrate, The surface of the cured conductive paste is the same, and the plate thickness is 300 μm or more and 2 mm or lessIs desirable.
[0016]
The present invention is directed to a method for manufacturing a substrate with a through electrode having a thickness t of 300 μm or more and 2 mm or less. A substrate having a thickness t of less than 300 μm is likely to be cracked or chipped during handling during processing or chip mounting after processing, and it is difficult to obtain a strong substrate with a through electrode. In a substrate with a through electrode having a plate thickness t of 2 mm or more, it is difficult to uniformly fill the through hole with the conductive paste.
[0017]
As a method of filling the through hole formed in the insulating substrate with the conductive paste, a method of injecting the conductive paste for each hole, a method of extruding the conductive paste from all the through holes of the insulating substrate, The screen printing method can be used. If the screen printing method is used, it is possible to fill all the through-holes arranged and formed in a precise pattern on the insulating base material with the conductive paste in a lump. In addition, it is possible to prevent unnecessary conductive paste from adhering to the surface of the insulating base material, which not only eliminates the need for a step of removing the adhering material in a subsequent process, but also saves the conductive paste, which is economical. Furthermore, if the screen printing method is used, it becomes easy to control the protruding height of the conductive paste which is important in the present invention. In the screen printing method, the protruding height of the conductive paste can be precisely controlled by spacing between the filling amount of the conductive paste and a stopper sheet set on the back surface of the insulating substrate.
[0018]
It is desirable that the protruding height when the conductive paste is filled in the through holes provided in the insulating base material is 50 μm or more and 200 μm or less. When the protruding height of the conductive paste is less than 50 μm, the region with a low filler powder concentration cannot be removed by processing, and an electrode with poor conduction may be generated in the substrate with a through electrode. Further, if the protruding height of the conductive paste is 200 μm or more, the amount of the conductive paste that is removed by processing increases, which is not economical and requires processing time. In order to more reliably remove the region having a low filler powder concentration and use the conductive paste more economically, it is more desirable that the protruding height of the conductive paste be 70 μm or more and 100 μm or less.
[0019]
In the processing of an insulating substrate containing a heat-cured conductive paste, it is desirable to process it to a smooth surface by grinding or lapping. By smoothing the surface of the substrate with through electrodes, it is possible to form a fine wiring pattern with high accuracy by photolithography. The single-sided processing amount of the insulating base material is desirably 3 μm or more and 50 μm or less. If the processing amount is less than 3 μm, it is difficult to averagely process the entire surface of the insulating base material, and a portion where the region where the filler powder concentration is low cannot be removed by processing occurs, and there is a conduction failure in the substrate with through electrodes. Electrodes can occur. If the processing amount is 50 μm or more, not only the processing time is lengthened, but also a thick insulating substrate must be used, which is not preferable because the manufacturing cost increases.
[0021]
The insulating base material is desirably ceramics, glass, resin, or a composite material thereof that has a proven track record for use as an electronic component and can be easily molded and has a required strength. The volume resistivity indicating the insulating property of the insulating base material is 10 from the viewpoint of maintaining electrical insulation between the electrodes and preventing the occurrence of a short circuit between the electrodes due to electromigration.¹⁰It is desirable that it is Ωcm or more. The heat resistance temperature of the insulating base material is preferably a material having a softening temperature of 250 ° C. or higher, more preferably 300 ° C. or higher, since the curing temperature of the conductive paste is around 200 ° C. Specific examples of materials include alumina, zirconia, silica, and BaTiO for ceramics.₃, CaTiO₃NiZn ferrite can be used. As glass, soda glass, borosilicate glass, lead glass, quartz glass, crystallized glass and the like can be used. As the resin, polyimide, polycarbonate, polyethersulfone, polysulfone, or the like can be used, and as the composite material, ceramic-glass composite material, glass-epoxy, or the like can be used.
[0023]
The through hole of the insulating base material is desirably formed easily and accurately industrially, and methods such as laser, shot blasting, punching, drilling, etching, and casting can be employed. In particular, shot blasting and etching are desirable methods because a large number of through-holes can be collectively formed in an insulating substrate. The diameter of the through hole is desirably 30 μm or more and 800 μm or less. A through hole having a diameter of less than 30 μm is difficult to form easily and stably, and it is difficult to uniformly fill the conductive paste. A through-hole having a diameter of 800 μm or more is not desirable because there is a problem that the conductive paste easily leaks between filling and curing. The through hole is not limited to a circle, but may be a square, an ellipse, or an indefinite shape. These diameters are defined by a diagonal line for a square, a long diameter for an ellipse, and an average length of the shortest diagonal line and the longest diagonal line for an indefinite shape.
[0025]
The binder resin is preferably composed mainly of a liquid epoxy resin having two or more epoxy groups. If a liquid epoxy resin is used, the conductive paste can be cured even at a low temperature of around 200 ° C. by selecting an appropriate curing agent. If the curing temperature is low, a simple device such as an oven can be used. Furthermore, even a material having a low heat-resistant temperature can be used as the insulating base material. The liquid epoxy resin having two or more epoxy groups includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, alicyclic epoxy resin, amine type epoxy resin, epoxy resin with naphthalene skeleton, and dimer acid glycidyl ester epoxy Resins and the like can be used alone or in combination. In particular, glycidyl ester epoxy resins have low viscosity and are flexible after curing. It is possible to increase the reliability of the conductive paste with respect to the thermal cycle by mixing and using these resins. In the conductive paste having low reliability with respect to the heat cycle, the contact state between the filler powder particles changes due to expansion and contraction due to heat, and the electric resistance changes.
[0026]
It is desirable that the curing agent added to the binder resin can be stored for a long time at room temperature without changing the characteristics in a mixed state with the epoxy resin, and has a characteristic of rapidly curing when heated to a predetermined temperature or higher. Curing agents include amine curing agents such as dicyandiamide and carboxylic acid hydrazide, imidazole curing agents such as 2-ethyl-4-methylimidazole, phthalic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, methyl nadic anhydride. Acid anhydride type curing agents such as acids, aromatic amine type (amine adduct) curing agents such as diaminodiphenylmethane and diaminodiphenylsulfonic acid, urea types such as 3- (3,4-dichlorophenyl) -1, 1-dimethylurea A curing agent, a cationic catalyst curing agent, a phenol curing agent, or the like can be used. The addition amount of the curing agent is preferably 0.2 to 3.0 wt%. When the addition amount is 3.0 wt% or more, the viscosity of the conductive paste increases, and it becomes difficult to fill the through holes. If the addition amount is 0.2 wt% or less, the resin may not be cured.
[0027]
A dispersant can be added because it has the effect of lowering the viscosity of the conductive paste and assisting the filling of the through holes. Dispersants include higher fatty acid ethylene oxide, propylene oxide addition ester, sorbitan and fatty acid ester compounds, polyhydric alcohols such as sorbitan, ethylene oxide, propylene oxide addition ether compounds, alkylbenzene ethylene oxide, propylene oxide addition products, etc. -Type dispersants, alkylbenzene sulfonic acid alkali salts, higher alcohol sulfuric acid ester alkali salts, phosphate ester compounds, higher fatty acids, higher fatty acid ethylene oxide, propylene oxide adduct sulfate alkaline salts, and the like, ammonium salt type Cationic dispersants and the like can be used. The addition amount of the dispersant is desirably 1.0 wt% or less. Addition of 1.0 wt% or more of the dispersion material is not desirable because the viscosity of the conductive paste is too low.
[0028]
As the filler powder, conductive powder particles such as noble metal, base metal, and carbon can be used. In order to obtain a through electrode having a small electric resistance and good electric conduction, a filler powder material having a small electric resistance is desirable. As a filler powder material with low electrical resistance, the volume resistivity is 20 × 10.^-6A material mainly containing a metal such as Pd, Pt, W, Ni, Sn, Zn, Fe, or the like that is Ωcm or less can be used. In order to obtain a through electrode having a smaller electrical resistance and good electrical conduction, the volume resistivity is 5.0 × 10^-6It is more preferable to use a material whose main component is a metal such as Au, Ag, Cu, or Al that is Ωcm or less. In order to prevent the surface oxidation of the filler powder particles, it is also possible to use a base metal powder particle surface coated with a noble metal. For example, filler powder particles obtained by coating Ag on the surface of Cu powder particles that are easily oxidized are desirable because they exhibit electrical resistance equivalent to that of Ag powder particles and are economical.
[0029]
The shape of the filler powder particles may be spherical, elliptical, hexahedral, octahedral or higher polyhedral, plate-like, flake-like, needle-like, irregular shapes in which regularity is difficult to find, or a combination thereof. It is possible to use a shape. It is also possible to use particles in which a plurality of particles are combined instead of a single particle. Spherical and flaky particles can be produced by industrially easy methods such as an atomizing method and a reducing method, and thus are more desirable as filler powder particles.
[0030]
The average particle size of the filler powder particles is desirably 1.0 μm or more and 8.0 μm or less in the case of a spherical shape, and 3 μm or more and 20 μm or less in the case of a flake shape. The particle size of the filler powder particles herein is obtained by observing a small amount of filler powder particles adhered to the conductive adhesive tape with a scanning electron microscope. The longest diameter of each particle measured from the observation image is defined as the particle diameter, and the average value of the particle diameters of all the particles included in an arbitrary observation field is defined as the average particle diameter. A filler powder having an average particle size smaller than the above range is not desirable because it has a large specific surface area with respect to volume and is likely to be oxidized. In addition, since the number of contact points between particles increases, the contact resistance tends to increase. On the other hand, a filler powder having an average particle size larger than the above range is not desirable because, on the contrary, the number of contact points between particles is reduced, the electrical resistance is increased, and the reliability with respect to the heat cycle after curing of the conductive paste is lowered. Since the flaky filler powder tends to have a higher viscosity when the same mixing weight is used as compared with the spherical filler powder, it is difficult to perform screen printing, so it is necessary to change the screen printing conditions. A mixture of spherical filler powder particles, flaky filler powder particles, and filler powder particles of other shapes can also be used. By mixing, it is possible to take advantage of the advantages of the flaky filler powder particles having low contact resistance and the spherical filler powder particles having excellent adhesion to the insulating substrate.
[0031]
The amount of filler powder mixed with the conductive paste is desirably 85 wt% or more and 93% wt or less. If the amount of the filler powder is less than 85 wt%, it is desirable because the number of contacts between the filler powder particles after curing the conductive paste is reduced, the electrical resistance is increased, and the reliability with respect to the thermal cycle after curing the conductive paste is reduced. Absent. On the other hand, when the amount of the filler powder mixed is more than 93 wt%, the viscosity of the conductive paste becomes high and it is difficult to fill the through hole, which is not desirable. In order to obtain an electrode that can be more easily filled into the through hole and has high reliability with respect to the thermal cycle, it is more desirable that the amount of filler powder mixed with the conductive paste is 90 to 92 wt%.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings. In order to make the explanation easy to understand, the same reference numerals are used for the same parts and components. The manufacturing process of the board | substrate with a penetration electrode of this invention is demonstrated using FIG. A through hole 2 is formed in the insulating substrate 1 shown in FIG. 1a) as shown in FIG. 1b). FIG. 1c) shows an X-X ′ cross section of FIG. 1b). As shown in FIG. 1d), the through hole 2 is filled with a conductive paste and hardened so that the amount of protrusion (h, h ') is generated. Next, as shown in FIG. 1e), the surface of the insulating base material 1 was processed on both sides with a processing amount (w, w ') to obtain a substrate 4 with through electrodes.
[0033]
The results of various investigations on the thickness t of the insulating base material, the size of the through hole, the amount of protrusion of the conductive paste, the amount of processing of the insulating base material, etc. The appropriate range of the amount and the processing amount of the insulating substrate will be described in detail. Table 1 shows the evaluation results of the electrical resistance values of the through electrodes in which the plate thickness t and material of the insulating base material and the size of the through holes were changed.
[0034]
Table 1

[0035]
The samples in Table 1 used polyimide and glass-epoxy substrate for the insulating substrate. The shape of the polyimide substrate was a square of 100 mm square, and the thickness was two types of 1.5 mm and 3.0 mm. The shape of the glass-epoxy substrate was a 120 mm square, and the thicknesses were 1.8 mm and 2.4 mm. A micro-drilling machine using an NC drill was used to form the through-hole, and two types of through-holes having a diameter of 200 μmφ and 400 μmφ were formed. The through-holes were formed at equal intervals of 2 mm pitch, and the number of base materials was prepared so that electrodes were formed in 1000 through-holes for each condition, and a substrate with through electrodes was produced. The conductive paste uses a mixture of bisphenol A type epoxy resin (Epicoat 828 made by Yuka Shell Epoxy) and alicyclic epoxy resin (ST-1000 made by Tohto Kasei) as the binder resin, and is cured. An amine adduct curing agent (MY-24 Ajinomoto Co., Inc.) was used as the agent, and a phosphate ester (an anionic surfactant “Blysurf”, manufactured by Daiichi Kogyo Seiyaku) was used as the dispersant. The curing agent and the dispersing agent were added at 0.2 wt% and 0.2 wt%, respectively, in the conductive paste ratio. As the filler powder, spherical Ag particles having an average particle diameter of 2.1 μm were used, and 90.5 wt% was added in a conductive paste ratio. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The kneaded conductive paste had a viscosity of 1300 to 1400 Pa · s (rotation speed: 0.5 RPS) as measured with an E-type viscometer at room temperature. The through-hole was filled with the conductive paste using a screen printing machine under the condition that h and h 'shown in FIG. The conductive paste is cured using an oven at 200 ° C. × 60 min, and then lapped on both sides of the insulating base material with w and w ′ shown in FIG. A substrate was obtained.
[0036]
The resistance values at both ends were measured for 1000 through electrodes under each condition. In an electrode of a substrate with a through electrode using a 3.0 mm thick polyimide substrate and a 2.4 mm glass-epoxy substrate, 2 × 10 in terms of volume resistivity^-4An electrode showing a large resistance value of Ωcm or more was contained in 70% or more of the whole. Further, most of the electrodes were electrodes that had no electrical continuity and could not be used as penetrating electrodes. This is presumably because the insulating substrate was thick and the conductive paste could not be uniformly filled in the through holes. In the substrate with through electrodes having a thickness of 2 mm or less, which is an example of the present invention, all the electrodes are 2 × 10 in terms of volume resistivity.^-4Since it was confirmed that a through electrode having a resistance value of Ωcm or less and having good electrical continuity was formed, the evaluation result was “◯”.
[0037]
Table 2 shows the through electrode when the thickness and material of the insulating base material, the size of the through hole, the method of forming the through hole, the protruding height h of the conductive paste, and the processing amount of the insulating base material are changed. The evaluation result of the electrical resistance value of is shown.
[0038]
Table 2

[0039]
For the samples in Table 2, sintered alumina having a purity of 96% and alkali-free glass (# 1737 by Corning) were used as the insulating base material. The shape of the alumina substrate was a disc shape of 75 mmφ and the thickness was 1.0 mm, and the shape of the alkali-free glass substrate was a disc shape of 150 mmφ and the thickness was 0.7 mm. A 150 μmφ circular through hole was formed on the alumina substrate by a carbon dioxide laser processing machine, and a 200 μmφ circular through hole was formed on the non-alkali glass substrate by a resist mask and shot blasting. The through-holes were formed at equal intervals of 2 mm pitch, and the number of base materials was prepared so that electrodes were formed in 1000 through-holes for each condition, and a substrate with through electrodes was produced. The conductive paste used was a mixture of bisphenol A type epoxy resin (Epicoat 828 made by Yuka Shell Epoxy) and alicyclic epoxy resin (ST-1000 made by Tohto Kasei) 1: 1 as the binder resin. An amine adduct type curing agent (manufactured by MY-24 Ajinomoto) was used as a curing agent, and a phosphate ester (an anionic surfactant “Blysurf” manufactured by Daiichi Kogyo Seiyaku) was used as a dispersing agent. The curing agent and the dispersing agent were added at 0.2 wt% and 0.2 wt%, respectively, in the conductive paste ratio. As the filler powder, spherical Ag particles having an average particle diameter of 2.1 μm were used, and 90.5 wt% was added in a conductive paste ratio. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The kneaded conductive paste had a viscosity of 1300 to 1400 Pa · s (rotation speed: 0.5 RPS) as measured with an E-type viscometer at room temperature. The through-holes were filled with the conductive paste using a screen printing machine, changing the protrusion height h shown in FIG. The protruding height h ′ of the back side conductive paste of the insulating substrate was set to 100 μm by adjusting the spacer of the screen printer. The conductive paste was thermally cured using an oven at 200 ° C. for 60 minutes, and then lapped by changing the surface processing amount w of the insulating base shown in FIG. 1e) to obtain a substrate with a through electrode. At this time, the processing amount w ′ on the back side of the insulating base material was set to 20 μm.
[0040]
The resistance values at both ends were measured for 1000 through electrodes under each condition. Under the condition that the protruding height h of the conductive paste is 50 μm or less and the condition that the substrate processing amount w is less than 3 μm, 2 × 10 in terms of volume resistivity.^-4Since 50% or more of the electrodes having a large resistance value of Ωcm or more were included, an evaluation result of × was obtained. This is because the region 32 where the filler powder concentration shown in FIG. 2a) is thin remains in the electrode because the protruding height h of the conductive paste or the substrate processing amount w is small, and the resistance value of the electrode is increased. It is done. In the substrate with through electrodes of the example having both the protruding height h of 50 μm or more and the base material processing amount of 3 μm or more, all electrodes are 2 × 10 in terms of volume resistivity.^-4Since it was confirmed that a through electrode having a resistance value of Ωcm or less and having good electrical continuity was formed, the evaluation result was “◯”.
[0041]
Table 3 shows the evaluation results of the electrical resistance value of the through electrode when the plate thickness t and material of the insulating base material, the size of the through hole, and the formation method of the through hole are changed.
[0042]
Table 3

[0043]
In the sample of Table 3, sintered alumina having a purity of 96% and a polyimide substrate were used as the insulating substrate. The shape of the alumina base material was a disk shape of 75 mmφ and the thickness was 0.6 mm, and the shape of the polyimide base material was a 100 mm square and the thickness was 1.5 mm. For the formation of through holes in an insulating substrate, a laser processing machine using a carbon dioxide laser is used for an alumina base material, and a punching machine using a punch is used for a polyimide base material. Formed. The through-holes were formed at equal intervals of 2 mm pitch, and the number of base materials was prepared so that electrodes were formed in 1000 through-holes for each condition, and a substrate with through electrodes was produced. The conductive paste uses a mixture of bisphenol A type epoxy resin (Epicoat 828 made by Yuka Shell Epoxy) and alicyclic epoxy resin (ST-1000 made by Tohto Kasei) as the binder resin, and is cured. An amine adduct curing agent (MY-24 Ajinomoto Co., Inc.) was used as the agent, and a phosphate ester (an anionic surfactant “Blysurf”, manufactured by Daiichi Kogyo Seiyaku) was used as the dispersant. The curing agent and the dispersing agent were added at 0.2 wt% and 0.2 wt%, respectively, in the conductive paste ratio. As the filler powder, spherical Ag particles having an average particle diameter of 2.1 μm were used, and 90.5 wt% was added in a conductive paste ratio. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The viscosity of the kneaded conductive paste was 1300 to 1400 Pa · s (rotation speed: 0.5 RPS) as measured with an E-type viscometer at room temperature. The through-hole was filled with the conductive paste using a screen printing machine under the condition that h and h 'shown in FIG. After the conductive paste is cured using an oven at 200 ° C. for 60 minutes, the surface of the insulating base material is lapped on the condition that w and w ′ are both 20 μm as shown in FIG. A substrate was obtained.
[0044]
The resistance values at both ends were measured for 1000 through electrodes under each condition. For a substrate using an alumina base material with a through hole diameter of 18 μm, 2 × 10 in terms of volume resistivity.^-4An electrode showing a large resistance value of Ωcm or more was contained in 70% or more of the whole. Further, most of the electrodes were electrodes that had no electrical continuity and could not be used as penetrating electrodes. This is presumably because the diameter of the through hole was small and the conductive paste could not be filled uniformly. Moreover, in the board | substrate using the polyimide base material whose diameter of a through-hole is 900 micrometers, there exist the through-hole from which the paste dripped immediately after filling, and could not be filled with the conductive paste stably. In the substrate with a through electrode having a through hole diameter of 30 μm or more and 800 μm or less, which is an example of the present invention, all electrodes are 2 × 10 in terms of volume resistivity.^-4Since it was confirmed that a through electrode having a resistance value of Ωcm or less and having good electrical continuity was formed, the evaluation result was “◯”.
[0045]
Table 4 shows the evaluation result of the electrical resistance value of the through electrode and the thermal cycle test result when the average particle diameter of the filler powder in the conductive paste and the shape of the filler powder particle are changed.
[0046]
Table 4

[0047]
In the samples in Table 4, non-alkali glass (manufactured by # 1737 Corning) was used as the insulating base material. The shape of the insulating substrate was a disc shape of 150 mmφ and the thickness was 0.7 mm. The diameter of the through hole was 200 μm, and after forming a resist mask on the glass substrate, a circular through hole was formed by applying shot blasting. The through-holes were formed at equal intervals of 2 mm pitch, and the number of base materials was prepared so that electrodes were formed in 1000 through-holes for each condition, and a substrate with through electrodes was produced. The conductive paste uses a mixture of a bisphenol F-type epoxy resin (Epicoat 807 made by oiled shell epoxy) and a dimer acid epoxidized resin (epoxy equivalent 400 to 500 g / eq) as a binder resin. The mixing ratio was adjusted such that the final conductive paste had a viscosity of 1200 to 1300 Pa · s (rotation speed 0.5 RPS) as evaluated by an E-type viscometer at room temperature. As the curing agent, dicyandiamide (DICY7 oil-made shell epoxy) was used, and as the dispersing agent, an anionic surfactant (Katiogen Daiichi Kogyo Seiyaku) was used. The curing agent and the dispersing agent were added at 1.0 wt% and 0.3 wt%, respectively, in the conductive paste ratio. As the filler powder, powders having different average particle diameters shown in Table 4 were used, and 90.5 wt% was added in a conductive paste ratio. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The through-hole was filled with the conductive paste using a screen printing machine under the condition that h and h 'shown in FIG. The conductive paste is cured using an oven at 200 ° C. for 60 minutes, and then lapped on both surfaces of the insulating substrate under the condition that w and w ′ are both 20 μm as shown in FIG. I got a substrate.
[0048]
The resistance values at both ends were measured for 1000 through electrodes under each condition. Under the condition that the average particle size of the spherical filler powder is 1.0 μm or less and the average particle size of the flaky filler powder is 3.0 μm or less, 20 × 10 in terms of volume resistivity.^-4An electrode showing a large resistance value of Ωcm or more was contained in 70% or more of the whole. This is presumably because the contact resistance due to the increase in the number of contact points between the particles because the filler powder particles are small. In other samples, all electrodes are 2 × 10 in terms of volume resistivity.^-4It was confirmed that a through electrode having a resistance value of Ωcm or less and good electrical conduction was formed.
[0049]
Volume resistivity 2 × 10 for all electrodes^-4When a substrate having a resistance value with good electrical continuity of Ωcm or less was put in a thermal cycle test of 1000 cycles at −55 ° C. to 125 ° C. for 30 minutes each, the average particle size of the spherical filler powder was 8 It was found that the resistance value increase after the thermal cycle test was as large as 3% under the condition of 0.0 μm or more and the average particle size of the flaky filler powder of 20 μm or less. Since the filler powder particles are large, the number of contact points between the particles is small, and it is considered that the reliability of the electrode with respect to the thermal cycle is low. In an embodiment of the present invention, all the electrodes were electrically operated under the condition that the spherical filler powder had an average particle size of 1.0 μm or more and 8.0 μm or less and the flaky filler powder had an average particle size of 3.0 μm or more and 20 μm or less. The electrical continuity showed a good resistance value, and the resistance value change after the thermal cycle test showed a good value of 1% or less.
[0050]
As explained with reference to Tables 1 to 4, the conductive paste is filled in the through-holes so that a protruding amount of 50 μm or more and 200 μm or less from the surface of the insulating base material is generated, and after heat curing, the conductivity is obtained. An insulating base material containing paste is processed by grinding or lapping at 5 μm or more and 50 μm or less on one side to obtain a substrate with a through electrode of 300 μm or more and 2 mm or less. As shown, the resistance value change after the thermal cycle test is small. Examples of the manufactured substrate with through electrodes within the manufacturing condition range of the present invention will be described below.
[0051]
As an example of the present invention, an example using a ceramic substrate is shown below. Sintered alumina with a purity of 96% was used for the insulating substrate. The volume resistivity of the insulating substrate is 1 × 10¹⁴Ωcm. The insulating base material was a disc shape of 75 mmφ and the thickness was 1.0 mm. The through hole was formed by a laser processing machine using a carbon dioxide gas laser, and was formed into a circle having a diameter of 150 μmφ. The through holes were formed at equal intervals of 2 mm pitch, the number of base materials was prepared so that electrodes were formed in 3000 through holes, and a substrate with through electrodes was prepared. The conductive paste uses a mixture of bisphenol A type epoxy resin (Epicoat 828 made by oil-coated shell epoxy) and alicyclic epoxy resin (made by ST-1000 Toto Kasei) 1: 1 as the binder resin, and cured. An amine adduct curing agent (MY-24 Ajinomoto Co., Inc.) was used as the agent, and a phosphate ester (an anionic surfactant “Blysurf”, manufactured by Daiichi Kogyo Seiyaku) was used as the dispersant. The curing agent and the dispersing agent were added at 0.2 wt% and 0.2 wt%, respectively, in the conductive paste ratio. As the filler powder, spherical Ag particles having an average particle diameter of 2.1 μm were used, and 90.5 wt% was added in a conductive paste ratio. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The kneaded conductive paste had a viscosity of 1300 to 1400 Pa · s (rotation speed: 0.5 RPS) as measured with an E-type viscometer at room temperature. The through-hole was filled with the conductive paste using a screen printing machine under the condition that h and h 'shown in FIG. After the conductive paste is cured using an oven at 200 ° C. × 60 min, the surface of the insulating substrate is lapped under the condition that w and w ′ shown in FIG. 1e) are both 20 μm, and 75 mmφ, 0 A substrate with a through electrode having a thickness of 96 mm was obtained.
[0052]
When resistance values at both ends of 3000 through electrodes were measured, all electrodes were 2 × 10 in terms of volume resistivity.^-4It was confirmed that a through electrode having a resistance value of Ωcm or less and good electrical conduction was formed.
[0053]
As another embodiment of the present invention, an example using a glass substrate is shown below. Non-alkali glass (manufactured by # 1737 Corning) was used for the insulating substrate. The volume resistivity of the insulating substrate is 3 × 10¹³Ωcm. The insulating base material was a disk shape of 150 mmφ, and the thickness was 0.7 mm. The diameter of the through hole was 200 μm, and a photoresist mask was formed on the glass substrate and then formed by applying shot blast. The through holes were formed at equal intervals of 2 mm pitch, the number of base materials was prepared so that electrodes were formed in 3000 through holes, and a substrate with through electrodes was prepared. The conductive paste uses a mixture of bisphenol A-type epoxy resin (Epicoat 828 made by oil-coated shell epoxy) and amine-type epoxy resin (ELN-125, manufactured by Sumitomo Chemical Co., Ltd.) as a binder resin, and is cured. An amine adduct curing agent (PN-23 Ajinomoto) was used as an agent, and a polyoxyethylene sorbitan fatty acid ester (nonionic surfactant “Sorgen” TW Daiichi Kogyo Seiyaku) was used as a dispersant. The curing agent and the dispersant were added in an amount of 0.3 wt% and 0.2 wt%, respectively, in the conductive paste ratio. As the filler powder, a powder obtained by coating Ag on spherical Cu particles having an average particle diameter of 4.9 μm produced by a reduction method was used, and 91.0 wt% was added in a conductive paste ratio. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The kneaded conductive paste had a viscosity of 1200 to 1300 Pa · s (rotation speed: 0.5 RPS) as measured with an E-type viscometer at room temperature. The through-hole was filled with the conductive paste using a screen printing machine under the condition that h and h 'shown in FIG. After the conductive paste is cured using an oven under the conditions of 180 ° C. × 60 min, the surface of the insulating substrate is lapped under the condition that w and w ′ shown in FIG. 1e) are both 20 μm, and 150 mmφ, 0 A substrate with a through electrode having a thickness of 66 mm was obtained.
[0054]
When resistance values at both ends of 3000 through electrodes were measured, all electrodes were 2 × 10 in terms of volume resistivity.^-4It was confirmed that a through electrode having a resistance value of Ωcm or less and good electrical conduction was formed.
[0055]
As another embodiment of the present invention, an example in which polyimide is used for an insulating substrate will be described below. The volume resistivity of the insulating substrate is 1 × 10¹⁶Ωcm. The insulating substrate was a 100 mm square and the thickness was 0.5 mm. The through hole was formed by a punching machine using a punch, and had an elliptical shape with a minor axis of 130 μm and a major axis of 180 μm. The through holes were formed at equal intervals of 2 mm pitch, the number of base materials was prepared so that electrodes were formed in 3000 through holes, and a substrate with through electrodes was prepared. As the binder resin, a bisphenol F type epoxy resin (Epicoat 807 made by oiled shell epoxy) and an epoxy resin obtained by glycidyl esterification of dimer acid (epoxy equivalent 400 to 500 g / eq) were mixed at 1: 3 as a binder resin. A dicyandiamide (DICY7 oil-made shell epoxy) was used as a curing agent, and an anionic surfactant (manufactured by Kachiogen Daiichi Kogyo Seiyaku) was used as a dispersant. The curing agent and the dispersing agent were added at 1.0 wt% and 0.3 wt%, respectively, in the conductive paste ratio. As the filler powder, a powder of flaky Ag particles having an average particle diameter of 10.5 μm was used, and 90.3 wt% was added in a conductive paste ratio. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The viscosity of the kneaded conductive paste was 1300 to 1400 Pa · s (rotation speed: 0.5 RPS) as measured with an E-type viscometer at room temperature. The through-hole was filled with the conductive paste using a screen printing machine under the condition that h and h 'shown in FIG. After the conductive paste is cured using an oven at 200 ° C. × 60 min, the surface of the insulating substrate is lapped under the condition that w and w ′ shown in FIG. A substrate with a through electrode having a thickness of 0.46 mm was obtained.
[0056]
When resistance values at both ends of 3000 through electrodes were measured, all electrodes were 2 × 10 in terms of volume resistivity.^-4It was confirmed that a through electrode having a resistance value of Ωcm or less and good electrical conduction was formed.
[0057]
As another embodiment of the present invention, an example in which a glass-epoxy substrate is used as an insulating substrate will be shown below. The insulating base material is a laminate of 6 sheets of 200 μm thick aramid non-woven epoxy sheets, and the volume resistivity of the insulating base material is 2 × 10.¹⁰Ωcm. The insulating substrate was a 120 mm square and the thickness was 1.2 mm. The through hole was formed by a micro drilling machine using an NC drill, and the diameter was a circle of 250 μmφ. The through holes were formed at equal intervals of 2 mm pitch, the number of base materials was prepared so that electrodes were formed in 3000 through holes, and a substrate with through electrodes was prepared. The conductive paste was mixed as a binder resin with a bisphenol A type epoxy resin (Epicoat 828 made by oiled shell epoxy) and an epoxy resin obtained by glycidyl ester of dimer acid (epoxy equivalent 400 to 500 g / eq) at a ratio of 1: 1. A phthalic anhydride was used as a curing agent, and a phosphate ester (an anionic surfactant “Blysurf” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used as a dispersing agent. The curing agent and the dispersant were added at 2.8 wt% and 0.2 wt%, respectively, in the conductive paste ratio. As the filler powder, a powder in which spherical Ag particles having an average particle diameter of 1.5 μm and flaky Ag particles having an average particle diameter of 11.2 μm were mixed at a ratio of 4: 6 was used, and 89.7 wt% of the conductive paste ratio was added. These binder resin and filler powder were stirred and kneaded while defoaming with a three roll. The kneaded conductive paste had a viscosity of 1200 to 1300 Pa · s (rotation speed: 0.5 RPS) as measured with an E-type viscometer at room temperature. The through-hole was filled with the conductive paste using a screen printing machine under the condition that h and h 'shown in FIG. After the conductive paste is cured using an oven at 200 ° C. × 60 min, the surface of the insulating substrate is lapped under the condition that w and w ′ shown in FIG. A substrate with a through electrode having a thickness of 1.14 mm was obtained.
[0058]
When resistance values at both ends of 3000 through electrodes were measured, all electrodes were 2 × 10 in terms of volume resistivity.^-4It was confirmed that a through electrode having a resistance value of Ωcm or less and good electrical conduction was formed.
[0059]
【The invention's effect】
Fill the through-hole formed in the insulating base material with resin-cured conductive paste,Put the substrate in an oven preheated to the curing temperature of the epoxy resin, create a temperature difference between the substrate surface and the inside of the substrate during the initial heating of the substrate, cure the epoxy resin, and have a thick filler concentration in the center of the substrate thickness A region is formed, and a region with a low filler concentration is formed in the vicinity of both surface edges of the substrate.After thermosettingThin region and insulating property of conductive paste with low filler concentrationMachining the substrate surface simultaneously. For increasing filler powder concentrationWith an easy method that does not require special equipment, it is possible to stably obtain an electrode with excellent electrical continuity.The insulating substrate surface and the conductive paste surface are the sameA method of manufacturing a substrate with a through electrode could be provided.
that's all
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a substrate showing a process flow of the present invention.
FIG. 2 is a cross-sectional view showing a filler powder concentration distribution of a conventional through electrode.
FIG. 3 is a diagram illustrating the formation of a region where the filler powder concentration is low.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Insulating base material, 2 Through-hole, 3 Conductive paste, 4 Substrate with a board, 30 Conductive paste before hardening, 31 Surface layer,
32 Area with low filler powder concentration after curing, 33 inside.

Claims (1)

A plurality of through holes are formed in an insulating base material made of ceramics, glass, resin or a composite material thereof by laser, shot blasting, punching, drilling, etching, etc., and a curing temperature of 180 ° C. or higher and 200 ° C. or lower is formed in the through holes. A conductive paste prepared by kneading a filler composed of conductive powder particles having an average particle size of 1.0 μm or more and 20 μm or less into an epoxy resin is filled in through holes, and the conductive paste surface is 50 μm or more and 200 μm from both sides of the substrate. After forming a convex at the following height, place the substrate at room temperature in an oven preheated to the curing temperature of the epoxy resin, and create a temperature difference between the substrate surface and the inside of the substrate during the initial heating of the substrate, thereby causing the epoxy resin The conductive paste filler powder concentration is thin at the both ends near the substrate surface. A thick low resistance region is formed inside the substrate and a region where the resistance value of the cured conductive paste is different, and the high resistance region at the edge of the substrate is removed by grinding or polishing at 3 μm or more and 50 μm or less on one side simultaneously with the substrate, A method for producing a substrate with a through electrode, comprising obtaining a substrate with a through electrode having the same surface of the cured conductive paste and having a thickness of 300 μm or more and 2 mm or less .

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