JP4175192B2

JP4175192B2 - Multilayer substrate manufacturing method

Info

Publication number: JP4175192B2
Application number: JP2003178603A
Authority: JP
Inventors: 敏一原田; 圭一新; 孝行森
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2003-06-23
Filing date: 2003-06-23
Publication date: 2008-11-05
Anticipated expiration: 2023-06-23
Also published as: JP2005019474A

Description

【０００１】
【発明の属する技術分野】
本発明は、熱可塑性樹脂からなる樹脂フィルムと導電材料からなる導体パターンとを多層に積層してなる多層基板の製造方法に関するものである。
【０００２】
【従来の技術】
従来、多層基板の製造方法として、導体パターンを形成した樹脂フィルムを積層し、それらを加熱しつつ加圧することにより樹脂フィルムを相互に接着し、多層基板を製造する方法が知られている。
【０００３】
例えば、特許文献１に開示された多層基板の製造方法によれば、熱可塑性樹脂からなる樹脂フィルムの両面に導体パターンを備える両面基板と熱可塑性樹脂からなる樹脂フィルムを積層し、積層した樹脂フィルムに熱プレス板を押し当て、熱可塑性樹脂を軟化させて接着させる。しかしながら、プレス板を直接樹脂フィルムに押し当て加熱・加圧した場合、例えば積層された樹脂フィルムの表面凹凸によってプレス板から樹脂フィルム各部が受ける圧力に差が生じるため、樹脂の流動量に差が生じ、導体パターンの位置ずれが発生しやすい。
【０００４】
そこで、本出願人は特願２００２−１００１１３号にて出願したように、積層された樹脂フィルムとプレス板との間に緩衝効果を有するプレス用部材を配置した。これにより、樹脂フィルム表面に凹凸があってもプレス用部材がその凹凸に応じて変形するため、樹脂フィルム各部における圧力差を縮小でき導体パターンの位置ずれを防止することができる。
【０００５】
【特許文献１】
特開２０００−３８４６４号公報
【０００６】
【発明が解決しようとする課題】
しかしながら、積層された樹脂フィルムは積層方向の上下からプレス板により加熱・加圧されるため、軟化した樹脂は自由度の高い樹脂フィルムの平面方向に流動する。上述のプレス用部材は樹脂フィルムの表面凹凸により樹脂フィルムに部分的に生じる圧力差（それに伴う樹脂の流動量差）を縮小させるものであるので、平面方向への樹脂の流動による導体パターンの位置ずれまでは低減することはできない。
【０００７】
本発明は上記問題点に鑑み、平面方向への樹脂の流動に伴う導体パターンの位置ずれを低減できる多層基板の製造方法を提供することを目的とする。
【００１６】
【課題を解決するための手段】
上記目的を達成する為に請求項１に記載の多層基板の製造方法は、熱可塑性樹脂からなる樹脂フィルムと導電性材料からなる導体パターンとを多層に積層し、積層体を形成する積層工程と、積層体を熱プレス板によって加熱しつつ加圧することにより、樹脂フィルムを相互に接着して多層基板を形成する加熱・加圧工程とを備える。そして、加熱・加圧工程において、積層体表面と熱プレス板との間に、積層体表面の凹凸に合わせて変形しつつ熱プレス板から積層体に加圧力を伝達する第１の緩衝部材を配置し、積層体の周辺部と熱プレス板との間に、積層体表面の凹凸に合わせて変形する加圧補助部材としての第２の緩衝部材を配置した状態で、熱プレス板により積層体を加熱しつつ加圧することにより、積層体の周辺部と該周辺部に囲まれた中央部における加熱・加圧条件に差を持たせ、第１の緩衝部材及び第２の緩衝部材を、積層体の端部から中央部とは反対方向に伸延された大きさとすることにより、熱プレス板の加圧によって第１の緩衝部材又は前記第２の緩衝部材を変形させて、その一部を積層体の側面に接触させることを特徴とする。
【００１７】
このように本発明によれば、積層体の周辺部と熱プレス板との間に加圧補助部材としての第２の緩衝部材を配置することにより、第２の緩衝部材の厚さ分、積層体の周辺部が中央部よりも早く加圧されて周辺部が圧縮される。また、第２の緩衝部材を配置することにより、積層体の周辺部が熱プレス板から受ける加圧力が増すので、積層体の周辺部と中央部における加熱・加圧条件に差が生じ、積層方向における積層体の周辺部の変形量（樹脂の圧縮量）が中央部の変形量よりも大きくなる。すなわち、中央部から周辺部への樹脂の流動を抑制することができる。また、第１の緩衝部材及び第２の緩衝部材を、積層体の端部から中央部とは反対方向に伸延された大きさとする。したがって、熱プレス板の加圧によって第１の緩衝部材又は第２の緩衝部材が変形して積層体の側面に接し、軟化した樹脂の平面方向への流動に対する抵抗となる。これにより、平面方向への樹脂の流動をより抑制することができる。
【００１８】
また、加熱・加圧工程において、積層体表面と熱プレス板との間には、積層体表面の凹凸に合わせて変形しつつ熱プレス板から積層体に加圧力を伝達する第１の緩衝部材を配置する。この第１の緩衝部材により、樹脂フィルムの表面凹凸により樹脂フィルムに部分的に生じる圧力差（それに伴う樹脂の流動量差）を縮小させることができるので、上述の平面方向の導体パターンの位置ずれ低減とともに、部分的な圧力差に伴う導体パターンの位置ずれを防止することもできる。
【００１９】
なお、請求項２に記載のように、第２の緩衝部材を、積層体と第１の緩衝部材との間に配置し、第２の緩衝部材の一部を、熱プレス板の加圧によって積層体の側面に接触させても良い。また、請求項３に記載のように、第２の緩衝部材を、第１の緩衝部材と熱プレス板との間に配置し、第１の緩衝部材の一部を、熱プレス板の加圧によって積層体の側面に接触させても良い。
【００２０】
次に、請求項４に記載の多層基板の製造方法は、熱可塑性樹脂からなる樹脂フィルムと導電性材料からなる導体パターンとを多層に積層し、積層体を形成する積層工程と、積層体を熱プレス板によって加熱しつつ加圧することにより、樹脂フィルムを相互に接着して多層基板を形成する加熱・加圧工程とを備える。そして、加熱・加圧工程において、積層体表面と熱プレス板との間に、積層体表面の凹凸に合わせて変形しつつ熱プレス板から積層体に加圧力を伝達する第１の緩衝部材を配置した状態で、熱プレス板により積層体を加熱しつつ加圧すると共に、第１の緩衝部材における積層体の周辺部に対応する部位に、第１の緩衝部材と同一材料からなる加圧補助部材を一体に設けて他の部位よりも肉厚の加圧補助部とすることにより、積層体の周辺部と該周辺部に囲まれた中央部における加熱・加圧条件に差を持たせ、第１の緩衝部材を積層体の端部から中央部とは反対方向に伸延された大きさとすることにより、熱プレス板の加圧によって第１の緩衝部材を変形させて、その一部を積層体の側面に接触させることを特徴とする。
【００２１】
このように本発明は、加圧補助部材を第１の緩衝部材と一体とした点以外は、請求項１に記載の発明と同じであるので、請求項１に記載の発明と同様の効果を期待することができる。
【００２２】
次に、請求項５に記載の多層基板の製造方法は、熱可塑性樹脂からなる樹脂フィルムと導電性材料からなる導体パターンとを多層に積層し、積層体を形成する積層工程と、積層体を熱プレス板によって加熱しつつ加圧することにより、樹脂フィルムを相互に接着して多層基板を形成する加熱・加圧工程とを備える。そして、加熱・加圧工程において、積層体表面と熱プレス板との間に、積層体表面の凹凸に合わせて変形しつつ熱プレス板から積層体に加圧力を伝達する第１の緩衝部材を配置し、積層体の周辺部と熱プレス板との間に、加熱・加圧時に軟化しない樹脂フィルムからなる加圧補助部材を配置した状態で、熱プレス板により積層体を加熱しつつ加圧することにより、積層体の周辺部と該周辺部に囲まれた中央部における加熱・加圧条件に差を持たせ、第１の緩衝部材を、積層体の端部から中央部とは反対方向に伸延された大きさとし、積層体と加圧補助部材との間に配置することにより、熱プレス板の加圧によって第１の緩衝部材を変形させて、その一部を積層体の側面に接触させることを特徴とする。
【００２３】
このように本発明は、加圧補助部材として加熱・加圧時に軟化しない樹脂フィルムを採用し、第１の緩衝部材を加圧により変形させて積層体の側面に接触させる点を限定する以外は、請求項１に記載の発明と同じであるので、請求項１に記載の発明と同様の効果を期待することができる。
【００２４】
次に、請求項６に記載の多層基板の製造方法は、熱可塑性樹脂からなる樹脂フィルムと導電性材料からなる導体パターンとを多層に積層し、積層体を形成する積層工程と、積層体を熱プレス板によって加熱しつつ加圧することにより、樹脂フィルムを相互に接着して多層基板を形成する加熱・加圧工程とを備える。そして、加熱・加圧工程において、積層体表面と熱プレス板との間に、積層体表面の凹凸に合わせて変形しつつ熱プレス板から積層体に加圧力を伝達する第１の緩衝部材を配置した状態で、熱プレス板により積層体を加熱しつつ加圧すると共に、熱プレス板における積層体の周辺部に対応する部位に、加圧補助部材を一体に設けて他の部位よりも積層体側に突出した加圧補助部とすることにより、積層体の周辺部と該周辺部に囲まれた中央部における加熱・加圧条件に差を持たせ、第１の緩衝部材を積層体の端部から中央部とは反対方向に伸延された大きさとすることにより、熱プレス板の加圧によって、第１の緩衝部材の一部を積層体の側面に接触させることを特徴とする。
【００２５】
このように本発明は、加圧補助部材を熱プレス板と一体とした点以外は、請求項１に記載の発明と同じであるので、請求項１に記載の発明と同様の効果を期待することができる。
【００２６】
ここで、加圧補助部材は、積層体の周辺部と熱プレス板との間に非連続的に設けられても良い。しかしながら、加圧補助部材間の隙間が大きいほど、当該隙間を通して中央部から周辺部方向へ樹脂が流動することとなる。従って、請求項７に記載のように、加圧補助部材は、積層体の周辺部の形状に対応して環状に設けられることが好ましい。
【００２７】
周辺部及び中央部の設定としては、請求項８に記載のように、多層基板としての電気的な接続機能を提供しない領域を周辺部とし、電気的な接続機能を提供する領域を中央部とすることが好ましい。多層基板において、導体パターンの形成されている領域は電気的な接続機能を提供する領域であるので、当該領域を中央部とすることで、導体パターンの位置ずれを低減することができる。
【００２８】
なお、本発明の製造方法により形成される多層基板は、積層方向における周辺部の厚さが中央部よりも薄くなるので、周辺部を予め不要領域（例えば電気的な接続機能を提供しない領域）として設定し、請求項９に示すように削除工程において削除することもできる。
【００２９】
その際、請求項２２に記載のように、周辺部は多層基板において電気的な接続機能を提供しない領域であり、中央部は電気的な接続機能を提供する領域であることが好ましい。請求項２０に記載の多層基板において、その断面を調査することにより、本発明の多層基板であることを識別することも可能である。
【００３０】
また、請求項２３に記載のように、熱可塑性樹脂は、熱可塑性樹脂からなる複数の樹脂フィルムにより構成され、周辺部と中央部における樹脂フィルムの積層数が同じであることが好ましい。請求項１９又は請求項２０に記載の多層基板において、厚さの異なる周辺部と中央部の積層枚数を調査することにより、本発明の多層基板であることを識別することも可能である。
【００３１】
【発明の実施の形態】
以下、本発明の実施の形態を図に基づいて説明する。
（第１の実施の形態）
図１は、本実施の形態における多層基板の製造工程を示す工程別断面図である。
【００３２】
図１（ａ）に示すように、片面導体パターンフィルム１は、樹脂フィルム２と当該樹脂フィルム２の片面に形成された導体パターン３とにより構成される。導体パターン３は、例えば樹脂フィルム２の片面に貼着された導体箔を所望のパターンにエッチングすることにより形成される。ここで、樹脂フィルム２としては、例えば熱可塑性樹脂であるポリエーテルエーテルケトン（ＰＥＥＫ）６５〜３５重量％とポリエーテルイミド（ＰＥＩ）３５〜６５重量％とからなる厚さ２５〜１００μｍの樹脂フィルムを用いることができる。また、導体箔としては、例えばＡｕ、Ａｇ、Ｃｕ、Ａｌの少なくとも１種を含む低抵抗金属箔を用いることができ、本実施の形態においては安価でマイグレーションの心配のないＣｕ箔を用いている。尚、導体パターン３の形成は、導体箔のエッチング以外にも、印刷法を用いて行われても良い。
【００３３】
導体パターン３の形成後、図１（ｂ）に示すように導体パターン３のない樹脂フィルム２の表面側から例えば炭酸ガスレーザを照射して、導体パターン３を底面とする有底孔のビアホール４を形成する。ビアホール４の形成には、炭酸ガスレーザ以外にもＵＶ−ＹＡＧレーザやエキシマレーザ等を用いることが可能である。その他にもドリル加工等により機械的にビアホールを形成することも可能であるが、小径でかつ導体パターン３を傷つけないように加工することが必要とされるため、レーザによる加工法を選択することが好ましい。
【００３４】
ビアホール４の形成が完了すると、図１（ｃ）に示すように、ビアホール４内に層間接続材料である導電性ペースト５を充填する。導電性ペースト５は、Ｃｕ、Ａｇ、Ｓｎ等の金属粒子に有機溶剤を加え、これを混練しペースト化したものである。尚、導電性ペースト５には、その他にも適宜低融点ガラスフリットや有機樹脂、或いは無機フィラーを添加混合しても良い。この、導電性ペースト５は、図示されないスクリーン印刷機やディスペンサ等を用いてビアホール４内に充填される。
【００３５】
ビアホール４への導電性ペースト５の充填が完了すると、図１（ｄ）に示すように、片面導体パターンフィルム１を複数枚（本例では４枚）位置決めして積層し、積層体１０を形成する。このとき、４枚の片面導体パターンフィルム１の内、積層の中心を境にして、上の２枚は導体パターン３が形成された面が上側に、下の２枚は導体パターン３が形成された面が下側になるように積層する。
【００３６】
このように、本実施の形態では、片面導体パターンフィルム１のみにより多層基板を構成する。従って、製造設備及び製造工程を簡素化でき、製造コストの低減に寄与できる。また、多層基板の上下両表面に導体パターン３による電極が形成されるので、高密度実装或いは多層基板の小型化を図ることができる。しかしながら、積層体１０の一方の表面にのみ導体パターン３が露出するように積層しても良い。
【００３７】
図１（ｄ）に示すように４枚の片面導体パターンフィルム１を積層する積層工程がなされた後、積層体１０の上下両面から加熱プレス機により加熱しつつ加圧する加熱・加圧工程がなされる。そして、加熱プレス後の冷却工程を経て、図１（ｅ）に示される多層基板２０が形成される。尚、多層基板２０は、加熱プレス機により、所定の温度勾配をもって冷却されるように管理される。この加熱・加圧工程については、以下に図２を用いて詳細に説明する。尚、図２は本実施形態の加熱・加圧工程を説明するための概略断面図である。
【００３８】
図２において、一対の熱プレス板３０は、複数枚（本実施形態では４枚）の片面導体パターンフィルム１を積層してなる積層体１０を、上下両側から挟むように配置される。この熱プレス板３０は、例えば、チタン等の導電性金属から構成されており、電流を通電することにより発熱する。それ以外にも、熱プレス板３０内にヒータを埋設して、そのヒータにより加熱したり、熱プレス板３０内に流体の流通経路を設け、その流通経路内に加熱された流体を流すことにより熱プレス板３０を加熱しても良い。
【００３９】
この熱プレス板３０の積層体１０への圧力印加面は平坦であり、直接熱プレス板３０が積層体１０を加熱・加圧すると、熱プレス板３０に接する積層体１０表面の凹凸や、積層体１０の内層の凹凸により、積層体１０の各部に印加される圧力に差が生じる場合がある。その結果、圧力を強く受けた部分の樹脂の流動量が他の部分の流動量よりも増加して、導体パターン３の位置ずれが生じることとなる。さらに、上記流動により、片面導体パターンフィルム１間に隙間が生じ、形成された多層基板２０にボイドが発生すると、層間剥離等の問題も生じる恐れがある。
【００４０】
このため、本実施の形態においては熱プレス板３０と積層体１０表面との間に、緩衝効果及び通気効果を有する第１の緩衝部材４０を設け、この第１の緩衝部材４０を介して、熱プレス板３０により加熱・加圧を行った。第１の緩衝部材４０として用いられる材料としては、ステンレス等の金属を繊維状に裁断し、その繊維状金属を不織布として板状に形成したものや、織布としてニット、クロスとしたもの（所謂ナスロン（登録商標））を用いることができる。それ以外にも、第１の緩衝部材４０は、後述する加熱・加圧工程条件以上の耐性を有し、熱プレス板３０の加圧面と積層体１０との形状差を緩衝できる形状に弾性変形可能な柔軟性を有するものであれば、他の材質及び構成のものを使用できる。例えば、ポリテトラフルオロエチレンフィルム、ケブラー(登録商標)及びポリテトラフルオロエチレン樹脂を特殊加工したハイパーシート（登録商標）ガスケット等の樹脂をフィルム或いは繊維化したもの、ガラス繊維などを用いることができる。さらに、減圧容器などに保管するなどして、予め片面導体パターンフィルム１間のエアが排除してある場合には、緩衝効果のみ発揮すれば良いので、耐熱性のゴムシート等を使用することもできる。
【００４１】
このように、緩衝効果を有する第１の緩衝部材４０を用いることにより、積層体１０の表面に凹凸があっても、その凹凸に応じて第１の緩衝部材４０が変形するため、積層体１０を構成する片面導体パターンフィルム１にほぼ均等に圧力が印加され、その結果、導体パターン３の位置ずれを防止することができる。
【００４２】
また、積層体１０はその積層方向の上下から熱プレス板３０により加熱・加圧されることにより、積層体１０を構成する樹脂フィルム２が軟化して塑性変形する。このとき、積層体１０の積層方向は熱プレス板３０により固定されているため、軟化した樹脂は自由度の高い片面導体パターンフィルム１の平面方向に流動する。従って、この平面方向（積層体１０の側面方向）への樹脂の流動によっても導体パターン３に位置ずれが生じる。
【００４３】
そこで、本実施形態においては、積層体１０の第１領域としての周辺部１１と熱プレス板３０との間に、加圧補助部材として一対の第２の緩衝部材５０を配置（図２においては積層体１０と第１の緩衝部材４０との間に配置）することにより、周辺部１１と当該周辺部１１に囲まれた中央部１２における加熱・加圧条件に差をもたせ、中央部１２から周辺部１１方向（平面方向）への樹脂の流動を抑制することとした。ここで、第１領域とは積層体１０に設けられた第２領域を取り囲む領域である。本実施形態においては、電気的な接続機能を提供する領域（導体パターン３及びビアホール４形成領域）である積層体１０の中央部１２を第２領域とし、電気的な接続機能を提供しない領域である周辺部１１を第１領域としている。また、積層体１０から１つの多層基板２０が形成されるものとする。
【００４４】
第２の緩衝部材５０は、第１の緩衝部材４０同様、緩衝効果を発揮できる材料を用いて形成されており、図３（ａ）に示すように、積層体１０の周辺部１１の形状に対応して環状に設けられている。また、積層体１０の周辺部１１を圧縮しすぎると（高い加圧力を与えすぎると）、周辺部１１の樹脂が中央部１２側に逆に流動し、周辺部１１近辺の導体パターン３に位置ずれが生じる恐れが有る。従って、樹脂の逆流動により中央部１２の導体パターン３に位置ずれが生じない程度の厚さ及び硬さをもって第２の緩衝部材５０が形成されている。本実施形態においては、第２の緩衝部材５０として、不織布のナスロン（登録商標）フェルト材を用いた。尚、図３（ａ）は第２の緩衝部材５０を説明するための平面図である。
【００４５】
このような第２の緩衝部材５０を配置し、平坦なプレス面をもつ熱プレス板３０により加圧した場合、第２の緩衝部材５０の厚さ分、積層体１０の周辺部１１が中央部１２よりも早く加圧され、周辺部１１の樹脂が先に圧縮される。また、第２の緩衝部材５０を配置することにより、積層体１０の周辺部１１が熱プレス板３０から受ける加圧力が増すので、周辺部１１の変形量（樹脂の圧縮量）が中央部１２の変形量よりも大きくなる。従って、所謂パッキンと同様の効果により、積層体１０の中央部１２から周辺部１１方向（片面導体パターンフィルム１の平面方向）への樹脂の流動が抑制される。すなわち、本実施の形態に示す多層基板２０の製造方法によれば、平面方向への樹脂の流動に伴う導体パターン３の位置ずれを低減することができる。尚、熱プレス板３０により積層体１０に印加される加熱・加圧条件は、例えば、温度は２００〜３５０℃の範囲の値であり、圧力は０．１〜１０ＭＰａの範囲の値である。
【００４６】
また、本実施形態において、加圧補助部材として変形可能な第２の緩衝部材５０を用いている。従って、図４の概略断面図に示すように、加熱・加圧時に第２の緩衝部材５０の一部が積層体１０の側面に接し、軟化した樹脂の平面方向への流動に対する抵抗となることも可能である。第２の緩衝部材５０において積層体１０の周辺部１１に対応する部位は、熱プレス板３０からの圧力を受けて積層体１０の周辺部１１と第１の緩衝部材４０との間で圧縮変形されつつ、積層体１０の周辺部１１に中央部１２よりも高い加圧力を伝達する。
【００４７】
それに対し、第２の緩衝部材５０において積層体１０の周辺部１１に対応する部位から中央部１２とは反対方向に伸延する伸延部５１は、熱プレス板３０からの加圧力を伝達すべき対象が無いので圧縮変形されず、積層体１０の側面に沿って伸びて積層体１０の側面に接することとなる。そして、軟化した樹脂の平面方向への流動に対する抵抗となる。このように、第２の緩衝部材５０が伸延部５１を有すると、積層体１０における平面方向への樹脂の流動をさらに抑制することができるので好ましい。尚、図４においては、積層体１０の両表面に配置した第２の緩衝部材５０の両伸延部５１により、積層体１０の側面が上面から下面まで塞がれた状態となっているが、一方の積層体１０表面に設けた第２の緩衝部材５０の伸延部５１が、積層体１０側面の上面から下面まで接しても良い。
【００４９】
また、本実施の形態において、第２の緩衝部材５０が図３（ａ）に示すように環状に設けられる例を示した。しかしながら、図３（ｂ）に示すように、所定の隙間５２をもって形成されても良い。しかしながら、隙間５２が大きいほど軟化した樹脂が第２領域から当該隙間５２を通して流出することとなるので、図３（ａ）に示すように環状に設けられることが好ましい。尚、図３（ｂ）は図３（ａ）の変形例を示す平面図である。
【００５０】
また、本実施の形態において、図２に示すように、第２の緩衝部材５０を積層体１０と第１の緩衝部材４０との間に配置する例を示した。しかしながら、第１の緩衝部材４０と熱プレス板３０との間に配置しても良い。
【００５１】
また、本実施の形態において、第２の緩衝部材５０は積層体１０の両表面上に設けられる例を示したが、いずれか一方にのみ設けられても良い。また、第１の緩衝部材４０も積層体１０の両表面上に設けられる例を示した。しかしながら、第１の緩衝部材４０はいずれか一方の表面上にのみ設けても良い。
【００５２】
また、本実施形態に示す製造方法により形成される多層基板２０は、周辺部１１と中央部１２における樹脂フィルム２の積層数が同じでありながらも、図１（ｅ）に示すように、周辺部１１（破線より側面側の部分）が中央部１２より薄肉の形状を有している。また、電気的な接続機能を提供しない領域を周辺部１１とし、電気的な接続機能を提供する領域を中央部１２としている。従って、その外観及び断面形状から本発明の多層基板２０であることを識別することも可能である。
【００５３】
尚、本実施形態において、周辺部１１は予め電気的な接続機能を提供しない不要領域としてパターン設計がなされているので、多層基板２０形成後に削除工程にて周辺部１１の削除を行っても良い。
【００５４】
（第２の実施の形態）
次に、本発明の第２の実施の形態を図５に基づいて説明する。図５は、本実施の形態における加熱・加圧工程を説明するための概略断面図であり、第１の実施形態の図２に対応している。
【００５５】
第２の実施の形態における多層基板２０の製造方法は、第１の実施の形態によるものと共通するところが多いので、以下、共通部分については詳しい説明は省略し、異なる部分を重点的に説明する。
【００５６】
第２の実施の形態において、第１の実施の形態と異なる点は、加圧補助部材が第１の緩衝部材４０の一部として一体に設けられた点である。
【００５７】
図５に示すように、本実施形態における加圧補助部材は、第１の緩衝部材４０の一部（加圧補助部４１）として、積層体１０の周辺部１１に対応する第１の緩衝部材４０の部位に一体に設けられている。
【００５８】
加圧補助部４１は、第１の緩衝部材４０と同一の材料により構成されており、第１の緩衝部材４０の加圧補助部４１形成部位は、第１の緩衝部材４０の他の部位よりも厚みを有している。また、図５に示すように、第１の緩衝部材４０は積層体１０の両表面とそれに対する熱プレス板３０との間に夫々配置され、加圧補助部４１は第１の緩衝部材４０から対向する第１の緩衝部材４０方向に突出した構造を有している。
【００５９】
このような加圧補助部４１を有する第１の緩衝部材４０を熱プレス板３０と積層体１０との間に配置し、平坦なプレス面をもつ熱プレス板３０により加圧した場合、積層体１０の周辺部１１が中央部１２よりも早く加圧され、周辺部１１の樹脂が先に圧縮される。また、第１の緩衝部材４０の加圧補助部４１形成部位は、他の部位よりも厚みを有しているので、積層体１０の周辺部１１が熱プレス板３０から受ける加圧力が増し、周辺部１１の変形量が中央部１２の変形量よりも大きくなる。従って、第１実施形態同様、積層体１０の中央部１２から周辺部１１方向（平面方向）への樹脂の流動が抑制される。すなわち、本実施形態に示す多層基板２０の製造方法によっても、平面方向への樹脂の流動に伴う導体パターン３の位置ずれを低減することができる。
【００６０】
尚、本実施形態においても、加圧補助部４１（を有する第１の緩衝部材４０）が積層体１０の周辺部１１に対応する部位と当該部位から中央部１２とは反対方向に伸延する伸延部とにより構成されることが好ましい。熱プレス板３０からの圧力を受けた際に、当該伸延部が積層体１０の側面に接して平面方向への樹脂の流動に対する抵抗となることことで、平面方向への樹脂の流動をさらに抑制することができる。
【００６１】
また、本実施の形態において、加圧補助部４１は周辺部１１の形状に応じて環状に設けられても良いし、第１の実施形態で示した第２の緩衝部材５０同様、所定の隙間をもって設けられても良い。しかしながら、環状に設けられる方が平面方向への樹脂の流動を抑制することに対して効果的である。
【００６２】
また、本実施の形態において、図５に示すように、第１の緩衝部材４０が積層体１０の両表面上に配置され、夫々に加圧補助部４１が有する例を示した。しかしながら、加圧補助部４１が一方の第１の緩衝部材４０にのみ設けられても良い。また、積層体１０の一方の表面上にのみ第１の緩衝部材４０が配置され、当該第１の緩衝部材４０が加圧補助部４１を有しても良い。
【００６３】
また、本実施の形態において、図５に示すように、加圧補助部４１は第１の緩衝部材４０から対向する第１の緩衝部材４０方向に突出し、第１の緩衝部材４０の他の部位よりも厚みをもって設けられる例を示した。しかしながら、第１の緩衝部材４０は柔軟性を有しているので、対向する第１の緩衝部材４０方向に突出していなくとも良い。例えば、加圧補助部４１が第１の緩衝部材４０の他の部位よりも厚みを有しつつ、当該第１の緩衝部材４０が接する熱プレス板３０方向に突出した構造であっても良い。この場合、積層体１０の周辺部１１が中央部１２よりも早く圧縮されることによる樹脂の流動抑制効果は得られないが、第１の緩衝部材４０は柔軟性を有しており、加圧補助部４１形成部位が肉厚であるので、積層体１０の周辺部１１には中央部１２より高い加圧力が印加され、その変形量は大きくなる。従って、平面方向への樹脂の流動を抑制することができる。
【００６４】
（第３の実施の形態）
次に、本発明の第３の実施の形態を図６に基づいて説明する。図６は、本実施形態における加熱・加圧工程を説明するための概略断面図であり、第１の実施形態の図２に対応している。
【００６５】
第３の実施の形態における多層基板２０の製造方法は、第１の実施の形態によるものと共通するところが多いので、以下、共通部分については詳しい説明は省略し、異なる部分を重点的に説明する。
【００６６】
第３の実施の形態において、第１の実施の形態と異なる点は、加圧補助部材が積層体１０の表面に積層される樹脂フィルムである点である。
【００６７】
本実施形態における加圧補助部材は、積層体１０の周辺部１１に応じた形状を有する環状の樹脂フィルム５１であり、図６に示すように４層の片面導体パターンフィルム１が積層されてなる積層体１０の両表面上に積層される。
【００６８】
この樹脂フィルム５１は、片面導体パターンフィルム１を構成する樹脂フィルム２と同一の熱可塑性樹脂であっても良いし、それ以外の熱可塑性樹脂、或いは熱硬化性樹脂であっても良い。しかしながら、加熱・加圧時に軟化する樹脂を用いると、樹脂フィルム５１自体が軟化して積層体１０の平面方向に流動する。積層体１０の周辺部１１に中央部１２よりも高い加圧力をかけるためには、その流動を見越してある程度の厚さが必要となる。従って、加熱・加圧時において軟化しない樹脂を樹脂フィルム５１として用いたほうが良い。
【００６９】
このような樹脂フィルム５１を積層体１０表面に積層し、平坦なプレス面をもつ熱プレス板３０により加圧した場合、積層体１０の周辺部１１が中央部１２よりも早く加圧され、周辺部１１の樹脂が先に圧縮される。また、樹脂フィルム５１は所定の厚みを有しているので、積層体１０の周辺部１１が熱プレス板３０から受ける加圧力が増し、周辺部１１の変形量が中央部１２の変形量よりも大きくなる。従って、第１実施形態同様、積層体１０の中央部１２から周辺部１１方向（平面方向）への樹脂の流動が抑制される。すなわち、本実施形態に示す多層基板２０の製造方法によっても、平面方向への樹脂の流動に伴う導体パターン３の位置ずれを低減することができる。
【００７０】
尚、本実施形態においても、樹脂フィルム５１が積層体１０の周辺部１１に対応する部位と当該部位から中央部１２とは反対方向に伸延する伸延部とにより構成され、熱プレス板３０からの圧力を受けた際に、当該伸延部が積層体１０の側面に接することができる材料をもって形成されることが好ましい。伸延部が平面方向への樹脂の流動に対する抵抗となることことで、平面方向への樹脂の流動をさらに抑制することができる。
【００７１】
また、本実施の形態において、樹脂フィルム５１が環状に設けられる例を記載したが、第１の実施形態で示した第２の緩衝部材５０同様、所定の隙間をもって形成されても良い。
【００７２】
また、図６において、樹脂フィルム５１は積層体１０の両表面上に設けられる例を示した。しかしながら、樹脂フィルム５１を積層体１０の少なくとも一方の表面上にのみ積層しても良い。
【００７３】
（第４の実施の形態）
次に、本発明の第４の実施の形態を図７に基づいて説明する。図７は、本実施形態における加熱・加圧工程を説明するための概略断面図であり、第１の実施形態の図２に対応している。
【００７４】
第４の実施の形態における多層基板２０の製造方法は、第１の実施の形態によるものと共通するところが多いので、以下、共通部分については詳しい説明は省略し、異なる部分を重点的に説明する。
【００７５】
第４の実施の形態において、第１の実施の形態と異なる点は、加圧補助部材が熱プレス板３０の一部として一体に設けられた点である。
【００７６】
図７に示すように、本実施形態の熱プレス板３０は、積層体１０の周辺部１１に対応する部分に、中央部１２に対応する部分よりも積層体１０方向に突出した環状の加圧補助部３１を有している。
【００７７】
このような加圧補助部３１を有する熱プレス板３０用いて積層体１０を加圧した場合、積層体１０の周辺部１１が中央部１２よりも早く加圧され、周辺部１１の樹脂が先に圧縮される。また、加圧補助部３１の厚さ分、積層体１０の周辺部１１が熱プレス板３０から受ける加圧力が増し、周辺部１１の変形量が中央部１２の変形量よりも大きくなる。従って、第１実施形態同様、積層体１０の中央部１２から周辺部１１方向（平面方向）への樹脂の流動が抑制される。すなわち、本実施形態に示す多層基板２０の製造方法によっても、平面方向への樹脂の流動に伴う導体パターン３の位置ずれを低減することができる。
【００７８】
尚、本実施の形態において、加圧補助部３１が環状に設けられる例を記載したが、第１の実施形態で示した第２の緩衝部材５０同様、所定の隙間をもって形成されても良い。
【００７９】
また、本実施の形態において、図７に示すように一対の熱プレス板３０の両方に加圧補助部３１が設けられる例を示した。しかしながら、一方の熱プレス板３０のみに加圧補助部３１が形成されても良いことは言うまでもない。
【００８０】
以上本発明の好ましい実施形態について説明したが、本発明は上述の実施形態のみに限定されず、種々変更して実施する事ができる。
【００８１】
本実施の形態において、樹脂フィルムはＰＥＥＫ樹脂６５〜３５％とＰＥＩ樹脂３５〜６５％とからなる熱可塑性樹脂フィルムであったが、ＰＥＥＫ及びＰＥＩを単独で用いることも可能である。更に、ポリエーテルサルフォン（ＰＥＳ）、ポリフェニレンエーテル（ＰＰＥ）、ポリエチレンナフタレート（ＰＥＮ）、液晶ポリマー、シンジオタクチック構造を有するスチレン系樹脂等を単独で用いても良いし、或いはＰＥＥＫ、ＰＥＩを含めそれぞれの内、いずれかを混合して用いても良い。要するに加熱・加圧工程において、樹脂フィルム同士の接着が可能であり、後工程であるはんだ付け等で必要な耐熱性を有する樹脂フィルムであれば好適に用いる事ができる。
【００８２】
また、本実施の形態において、樹脂フィルムとして、片面に導体パターンの形成された片面導体パターンフィルムを積層する例を示したが、それ以外にもコア基板を用いその上下に片面導体パターンフィルムを配置したり、コア基板の代わりに両面に導体パターンが形成された熱可塑性樹脂からなる加工樹脂フィルムを用いても良い。また、積層される樹脂フィルムの中には、その表面に導体パターンを有していない樹脂フィルムを含んでも良い。
【００８３】
また、本実施の形態において、ビアホール内に導電性ペースト充填する印刷法の例を示したが、それ以外にも無電解メッキ、電解メッキ、蒸着法、金属コート等を用いても良い。
【００８４】
また、本実施の形態において、有底のビアホールを形成し、この有底ビアホールに層間接続材料である導電性ペーストを充填したが、ビアホール形成時に貫通穴を形成し、この貫通ビアホールに層間接続材料を充填するものであっても良い。
【００８５】
また、本実施の形態において、樹脂フィルムを含む片面導体パターンフィルムを４枚積層する例を示したが、２枚以上であれば層数が限定されるものではないことは言うまでもない。
【００８６】
また、本実施の形態において、積層体の第２領域（中央部）から第１領域（周辺部）方向への樹脂の流動を抑制するような第１領域の加熱・加圧条件の具体例として、積層体の第１領域と熱プレス板との間に加圧補助部材（或いは加圧補助部）を配置する例を示した。しかしながら、加熱・加圧条件は上記例に限定されるものではない。それ以外にも、積層体の第１領域を第２領域よりも高い加圧力をもって加圧しても良い。例えば熱プレス板が分割構成され、積層体の周辺部に該当する部分を中央部に該当する部分よりも高い圧力設定とし、第１領域及び第２領域を同時に加圧しても良い。この場合、高い加圧力を受けた積層体の第１領域が第２領域よりも圧縮されるので、第２領域から第１領域方向への樹脂の流動を抑制することができる。
【００８７】
また、積層体の第１領域を第２領域よりも早い加圧開始タイミングをもって加圧しても良い。第１領域と第２領域に印加される圧力が同じであっても、先に第１領域を加圧することにより、第２領域の樹脂が流動する際に既に第１領域の樹脂が圧縮されていれば、第２領域から第１領域方向への樹脂の流動を抑制することができる。
【００８８】
また、加圧による第１領域の変形量が第２領域の変形量よりも大きくなるような加熱・加圧条件としても良い。加圧による変形量が大きいということは、積層方向における樹脂の圧縮量が大きいということである。すなわち第１領域における樹脂が第２領域よりも圧縮されるので、第２領域から第１領域方向への樹脂の流動を抑制することができる。
【００８９】
また、上述の加熱・加圧条件は、いずれも加圧条件を変更することで第２領域から第１領域方向への樹脂の流動を抑制するものであった。しかしながら、加熱条件を変更することにより、樹脂の流動を抑制しても良い。例えば、第１領域を第２領域よりも低い加熱温度をもって加熱することにより、第１領域の樹脂の流動量を第２領域の樹脂の流動量よりも小さくし、第２領域の樹脂の流動を抑制することができる。その際、第１領域の加熱温度は、第１領域の樹脂が塑性変形しない温度としても良い。
【００９０】
また、本実施形態において、第１の緩衝部材及び第２の緩衝部材は緩衝効果を発揮するために積層体の表面凹凸に合わせて変形可能に設けられており、加熱・加圧後に積層体及び熱プレス板から引き剥がしにくい場合がある。従って、第１の緩衝部材及び／又は第２の緩衝部材と当該緩衝部材が接する他の部材（積層体、熱プレス板）との間にポリイミド等からなる離型シートを配置すると良い。その際、緩衝部材全体を包み込むように離型シートを配置しても良い。
【図面の簡単な説明】
【図１】本発明の第１の実施形態における多層基板の製造工程を示す工程別断面図であり、（ａ）は導体パターン形成、（ｂ）はビアホール形成、（ｃ）は層間接続材料充填、（ｄ）は積層工程、（ｅ）は加熱・加圧工程後の多層基板を示す図である。
【図２】第１の実施形態における加熱・加圧工程を説明するための概略断面図である。
【図３】第２の緩衝部材の形状を説明するための補足図であり、（ａ）は平面図、（ｂ）は（ａ）の変形例を示す平面図である。
【図４】第２の緩衝部材の効果を説明するための概略断面図である。
【図５】第２の実施形態における加熱・加圧工程を説明するための概略断面図である。
【図６】第３の実施形態における加熱・加圧工程を説明するための概略断面図である。
【図７】第４の実施形態における加熱・加圧工程を説明するための概略断面図である。
【符号の説明】
２・・・樹脂フィルム
３・・・導体パターン
１０・・・積層体
１１・・・周辺部
１２・・・中央部
２０・・・多層基板
３０・・・熱プレス板
４０・・・第１の緩衝部材
５０・・・第２の緩衝部材[0001]
BACKGROUND OF THE INVENTION
  In the present invention, a resin film made of a thermoplastic resin and a conductor pattern made of a conductive material are laminated in multiple layers.Multilayer substrate manufacturing methodIt is about.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a method for producing a multilayer substrate, a method of producing a multilayer substrate by laminating resin films on which conductor patterns are formed and applying pressure while heating them is known.
[0003]
For example, according to the method for producing a multilayer substrate disclosed in Patent Document 1, a double-sided substrate having a conductor pattern on both sides of a resin film made of a thermoplastic resin and a resin film made of a thermoplastic resin are laminated, and the laminated resin film A hot press plate is pressed to soften the thermoplastic resin and bond it. However, when the press plate is directly pressed against the resin film and heated / pressed, for example, there is a difference in the pressure received by each part of the resin film from the press plate due to the surface unevenness of the laminated resin film, so there is a difference in the resin flow rate. This is likely to cause displacement of the conductor pattern.
[0004]
Therefore, the applicant has arranged a press member having a buffering effect between the laminated resin film and the press plate, as filed in Japanese Patent Application No. 2002-100113. Thereby, even if there is unevenness on the surface of the resin film, the pressing member is deformed according to the unevenness, so that the pressure difference in each part of the resin film can be reduced and the displacement of the conductor pattern can be prevented.
[0005]
[Patent Document 1]
JP 2000-38464 A
[0006]
[Problems to be solved by the invention]
However, since the laminated resin film is heated and pressurized by the press plate from above and below in the lamination direction, the softened resin flows in the plane direction of the resin film having a high degree of freedom. Since the above-mentioned pressing member reduces the pressure difference partially generated in the resin film due to the surface unevenness of the resin film (the resin flow amount difference associated therewith), the position of the conductor pattern due to the resin flow in the plane direction The deviation cannot be reduced.
[0007]
  In view of the above problems, the present invention can reduce the displacement of the conductor pattern due to the resin flow in the planar direction.Multilayer substrate manufacturing methodThe purpose is to provide.
[0016]
[Means for Solving the Problems]
  In order to achieve the above object, claim 1The multilayer substrate manufacturing method described in 1 is a method of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers, forming a laminated body, and heating the laminated body with a hot press plate. And a heating / pressurizing step in which the resin films are bonded to each other to form a multilayer substrate. And in the heating and pressurizing process,Between the laminate surface and the hot press plate, a first buffer member that transmits pressure from the hot press plate to the laminate while being deformed according to the irregularities of the laminate surface is disposed, By placing the second buffer member as a pressure auxiliary member that deforms according to the unevenness of the surface of the laminate between the hot press plate and pressurizing while heating the laminate with the hot press plate, The heating and pressurizing conditions in the peripheral part of the laminated body and the central part surrounded by the peripheral part have a difference, and the first buffer member and the second buffer member are separated from the end part of the laminated body to the central part. By making the size extended in the opposite direction, the first buffer member or the second buffer member is deformed by pressurization of the hot press plate, and a part thereof is brought into contact with the side surface of the laminate.It is characterized by that.
[0017]
  Thus, according to the present invention,LaminatedPeripheralPressurizing auxiliary member between the heat press plateAs a second cushioning memberBy placingSecond buffer memberThe thickness of the laminatePeripheralButCenterPressurized faster thanPeripheralIs compressed. Also,Second buffer memberOf the laminate by placingPeripheralIncreases the pressure applied from the hot press plate,Differences occur in the heating and pressurization conditions at the periphery and center of the laminateOf the laminate in the stacking directionPeripheralDeformation amount (resin compression amount)CenterIt becomes larger than the deformation amount. That is,CenterFromPeripheralIt is possible to suppress the flow of resin to the surface.Moreover, let the 1st buffer member and the 2nd buffer member be the magnitude | size extended in the direction opposite to a center part from the edge part of a laminated body. Therefore, the first buffer member or the second buffer member is deformed by pressurization of the hot press plate and comes into contact with the side surface of the laminate, thereby providing resistance to the flow of the softened resin in the planar direction. Thereby, the flow of the resin in the planar direction can be further suppressed.
[0018]
  Also,In the heating / pressurizing step, a first buffer member that transmits a pressing force from the hot press plate to the laminate while being deformed according to the unevenness of the laminate surface between the laminate surface and the hot press platePlace.By this first buffer member,Since the pressure difference partially generated in the resin film due to the unevenness of the surface of the resin film (the resin flow amount difference accompanying it) can be reduced, the displacement of the conductor pattern in the planar direction is reduced and the partial pressure difference To prevent misalignment of the conductor patternAlsoit can.
[0019]
  In addition, as described in claim 2, the second buffer member is disposed between the stacked body and the first buffer member, and a part of the second buffer member is pressed by a hot press plate. You may make it contact the side surface of a laminated body. According to a third aspect of the present invention, the second buffer member is disposed between the first buffer member and the heat press plate, and a part of the first buffer member is pressed against the heat press plate. You may make it contact the side surface of a laminated body by.
[0020]
  Next, a method for manufacturing a multilayer substrate according to claim 4 includes: a lamination step of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers to form a laminate; A heating / pressurizing step in which the resin films are bonded to each other to form a multilayer substrate by applying pressure while heating with a hot press plate. In the heating / pressurizing step, a first buffer member that transmits pressure from the hot press plate to the laminate while being deformed according to the unevenness of the laminate surface between the laminate surface and the hot press plate is provided. A pressurizing auxiliary member made of the same material as that of the first buffer member at a position corresponding to the peripheral portion of the stack of the first buffer member while pressing the laminate with the hot press plate in the arranged state By providing the pressure auxiliary part thicker than other parts, the heating / pressurization conditions in the peripheral part of the laminated body and the central part surrounded by the peripheral part are made different. The first buffer member is deformed from the end of the laminated body in the direction opposite to the central portion, so that the first buffer member is deformed by pressurization of the hot press plate, and a part of the buffer member is laminated. It is made to contact the side surface of this.
[0021]
  As described above, the present invention is the same as the invention according to claim 1 except that the pressure assisting member is integrated with the first buffer member, and therefore the same effect as the invention according to claim 1 is obtained. You can expect.
[0022]
  Next, a method for manufacturing a multilayer substrate according to claim 5 includes: a lamination step of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers to form a laminate; A heating / pressurizing step in which the resin films are bonded to each other to form a multilayer substrate by applying pressure while heating with a hot press plate. In the heating / pressurizing step, a first buffer member that transmits pressure from the hot press plate to the laminate while being deformed according to the unevenness of the laminate surface between the laminate surface and the hot press plate is provided. And pressurizing while heating the laminate with a hot press plate in a state where a pressure auxiliary member made of a resin film that does not soften during heating and pressurization is placed between the periphery of the laminate and the hot press plate Thus, the heating / pressurizing condition is different between the peripheral part of the laminate and the central part surrounded by the peripheral part, and the first buffer member is arranged in the direction opposite to the central part from the end of the laminate. The first buffer member is deformed by pressurization of the hot press plate, and a part of the first buffer member is brought into contact with the side surface of the laminate by arranging the stretched size between the laminate and the pressure auxiliary member. It is characterized by that.
[0023]
  As described above, the present invention employs a resin film that does not soften during heating and pressurization as a pressure assisting member, except that the first buffer member is deformed by pressurization and is in contact with the side surface of the laminate. Since the present invention is the same as that of the first aspect of the invention, the same effect as that of the first aspect of the invention can be expected.
[0024]
  Next, a manufacturing method of a multilayer substrate according to claim 6 includes a lamination step of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers to form a laminate, A heating / pressurizing step in which the resin films are bonded to each other to form a multilayer substrate by applying pressure while heating with a hot press plate. In the heating / pressurizing step, a first buffer member that transmits pressure from the hot press plate to the laminate while being deformed according to the unevenness of the laminate surface between the laminate surface and the hot press plate is provided. In the state where it is placed, the laminated body is pressed while being heated by a hot press plate, and a pressure assisting member is provided integrally in a portion corresponding to the peripheral portion of the laminated body in the hot pressed plate so that the laminated body side is more than the other portions. By providing the pressure assisting part protruding to the center, the heating / pressurizing conditions in the peripheral part of the laminate and the central part surrounded by the peripheral part are different, and the first buffer member is provided at the end of the laminate. The size of the first buffer member is made to contact with the side surface of the laminated body by pressurizing the hot press plate.
[0025]
  Thus, since this invention is the same as that of the invention of Claim 1 except the point which integrated the pressurization auxiliary member with the hot press board, the effect similar to the invention of Claim 1 is anticipated. be able to.
[0026]
  Here, the pressure assisting member may be discontinuously provided between the peripheral portion of the laminate and the hot press plate. However, the larger the gap between the pressure assisting members, the more the resin flows from the central portion toward the peripheral portion through the gap. Therefore, as described in claim 7, it is preferable that the pressure assisting member is provided in an annular shape corresponding to the shape of the peripheral portion of the laminate.
[0027]
  As the setting of the peripheral portion and the central portion, as described in claim 8, a region that does not provide an electrical connection function as a multilayer substrate is a peripheral portion, and a region that provides an electrical connection function is a central portion. It is preferable to do. In the multilayer substrate, the region where the conductor pattern is formed is a region that provides an electrical connection function. Therefore, the position shift of the conductor pattern can be reduced by setting the region as the central portion.
[0028]
  In the multilayer substrate formed by the manufacturing method of the present invention, the thickness of the peripheral portion in the stacking direction is thinner than that of the central portion, so that the peripheral portion is preliminarily an unnecessary region (for example, a region that does not provide an electrical connection function). And can be deleted in the deletion step as shown in claim 9.
[0029]
In that case, as described in claim 22, it is preferable that the peripheral portion is a region that does not provide an electrical connection function in the multilayer substrate, and the central portion is a region that provides an electrical connection function. It is also possible to identify the multilayer substrate according to the present invention by examining the cross section of the multilayer substrate according to claim 20.
[0030]
In addition, as described in claim 23, the thermoplastic resin is preferably composed of a plurality of resin films made of a thermoplastic resin, and the number of laminated resin films in the peripheral part and the central part is preferably the same. In the multilayer substrate according to claim 19 or 20, it is possible to identify the multilayer substrate of the present invention by investigating the number of stacked peripheral portions and central portions having different thicknesses.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view for each process showing the manufacturing process of the multilayer substrate in the present embodiment.
[0032]
As shown in FIG. 1A, the single-sided conductor pattern film 1 includes a resin film 2 and a conductor pattern 3 formed on one side of the resin film 2. The conductor pattern 3 is formed, for example, by etching a conductor foil attached to one surface of the resin film 2 into a desired pattern. Here, as the resin film 2, for example, a resin film having a thickness of 25 to 100 μm composed of 65 to 35% by weight of polyetheretherketone (PEEK) which is a thermoplastic resin and 35 to 65% by weight of polyetherimide (PEI). Can be used. Further, as the conductor foil, for example, a low resistance metal foil containing at least one of Au, Ag, Cu, and Al can be used. In the present embodiment, a Cu foil that is inexpensive and does not cause migration is used. . In addition, formation of the conductor pattern 3 may be performed using the printing method besides the etching of the conductor foil.
[0033]
After the formation of the conductor pattern 3, as shown in FIG. 1 (b), for example, a carbon dioxide gas laser is irradiated from the surface side of the resin film 2 without the conductor pattern 3, and the via hole 4 having a bottomed hole with the conductor pattern 3 as the bottom surface is formed. Form. For the formation of the via hole 4, it is possible to use a UV-YAG laser, an excimer laser or the like in addition to the carbon dioxide laser. In addition, it is possible to form via holes mechanically by drilling or the like, but since it is necessary to process so as not to damage the conductor pattern 3 with a small diameter, a laser processing method should be selected. Is preferred.
[0034]
When the formation of the via hole 4 is completed, as shown in FIG. 1C, the via hole 4 is filled with a conductive paste 5 that is an interlayer connection material. The conductive paste 5 is a paste obtained by adding an organic solvent to metal particles such as Cu, Ag, Sn, and kneading them. In addition, the conductive paste 5 may be additionally mixed with a low melting point glass frit, an organic resin, or an inorganic filler as appropriate. The conductive paste 5 is filled into the via hole 4 using a screen printing machine, a dispenser or the like (not shown).
[0035]
When the filling of the conductive paste 5 into the via hole 4 is completed, as shown in FIG. 1D, a plurality of single-sided conductor pattern films 1 (four in this example) are positioned and laminated to form a laminate 10. To do. At this time, of the four single-sided conductor pattern films 1, the upper two sheets have the conductor pattern 3 formed on the upper side, and the lower two sheets have the conductor pattern 3 formed on the center of the lamination. Laminate so that the surface is on the bottom.
[0036]
Thus, in this Embodiment, a multilayer substrate is comprised only with the single-sided conductor pattern film 1. FIG. Therefore, the manufacturing equipment and the manufacturing process can be simplified, and the manufacturing cost can be reduced. In addition, since the electrodes of the conductor pattern 3 are formed on the upper and lower surfaces of the multilayer substrate, high-density mounting or a reduction in size of the multilayer substrate can be achieved. However, lamination may be performed so that the conductor pattern 3 is exposed only on one surface of the laminate 10.
[0037]
After the lamination process of laminating four single-sided conductor pattern films 1 as shown in FIG. 1 (d), a heating / pressurizing process is performed in which pressure is applied while heating with a heat press from both the upper and lower surfaces of the laminate 10. The And the multilayer substrate 20 shown by FIG.1 (e) is formed through the cooling process after hot press. The multilayer substrate 20 is managed by a heating press so that it is cooled with a predetermined temperature gradient. This heating / pressurizing step will be described in detail below with reference to FIG. FIG. 2 is a schematic cross-sectional view for explaining the heating / pressurizing process of the present embodiment.
[0038]
In FIG. 2, the pair of hot press plates 30 are arranged so as to sandwich a laminated body 10 formed by laminating a plurality of (four in the present embodiment) single-sided conductor pattern films 1 from both the upper and lower sides. The hot press plate 30 is made of, for example, a conductive metal such as titanium, and generates heat when a current is applied. In addition, a heater is embedded in the heat press plate 30 and heated by the heater, or a fluid flow path is provided in the heat press plate 30 and the heated fluid is caused to flow in the flow path. The hot press plate 30 may be heated.
[0039]
The pressure application surface of the heat press plate 30 to the laminate 10 is flat, and when the heat press plate 30 directly heats and presses the laminate 10, irregularities on the surface of the laminate 10 in contact with the heat press plate 30, Due to the unevenness of the inner layer of the body 10, there may be a difference in the pressure applied to each part of the laminated body 10. As a result, the flow amount of the resin in the portion that is strongly subjected to pressure increases more than the flow amount in the other portions, and the positional deviation of the conductor pattern 3 occurs. Furthermore, if a gap occurs between the single-sided conductor pattern films 1 due to the flow and voids are generated in the formed multilayer substrate 20, problems such as delamination may occur.
[0040]
For this reason, in the present embodiment, a first buffer member 40 having a buffering effect and a ventilation effect is provided between the hot press plate 30 and the surface of the laminated body 10, and the first buffer member 40 is interposed through the first buffer member 40. Heating and pressing were performed by the hot press plate 30. As a material used as the first buffer member 40, a metal such as stainless steel is cut into a fiber shape, and the fiber metal is formed into a plate shape as a nonwoven fabric, or a knitted fabric or a cloth as a woven fabric (so-called Naslon (registered trademark)) can be used. In addition, the first buffer member 40 has a resistance higher than the heating and pressurizing process conditions described later, and is elastically deformed into a shape that can buffer the shape difference between the pressing surface of the hot press plate 30 and the laminate 10. Other materials and configurations can be used as long as they have the possible flexibility. For example, a polytetrafluoroethylene film, a Kevlar (registered trademark) and a hypersheet (registered trademark) gasket obtained by specially processing a polytetrafluoroethylene resin, a film or fiberized resin, glass fiber, or the like can be used. Furthermore, when the air between the single-sided conductor pattern films 1 is excluded in advance by storing in a decompression container or the like, it is sufficient to exhibit only a buffering effect, so a heat-resistant rubber sheet or the like may be used. it can.
[0041]
In this way, by using the first buffer member 40 having a buffering effect, even if the surface of the laminate 10 has irregularities, the first buffer member 40 is deformed according to the irregularities, so the laminate 10 Is applied to the single-sided conductor pattern film 1 that constitutes substantially uniformly, and as a result, displacement of the conductor pattern 3 can be prevented.
[0042]
Moreover, the laminated body 10 is heated and pressurized by the hot press plate 30 from above and below in the laminating direction, so that the resin film 2 constituting the laminated body 10 is softened and plastically deformed. At this time, since the lamination direction of the laminated body 10 is fixed by the hot press plate 30, the softened resin flows in the planar direction of the single-sided conductor pattern film 1 having a high degree of freedom. Accordingly, the conductor pattern 3 is also displaced due to the flow of the resin in the planar direction (the side surface direction of the multilayer body 10).
[0043]
Therefore, in the present embodiment, a pair of second buffer members 50 are disposed as a pressure auxiliary member between the peripheral portion 11 as the first region of the laminate 10 and the hot press plate 30 (in FIG. 2). By arranging the laminated body 10 and the first buffer member 40), the heating / pressurizing conditions in the peripheral portion 11 and the central portion 12 surrounded by the peripheral portion 11 are different from each other. Resin flow in the direction of the peripheral portion 11 (planar direction) was suppressed. Here, the first region is a region surrounding the second region provided in the stacked body 10. In the present embodiment, the central portion 12 of the stacked body 10 which is a region providing the electrical connection function (region where the conductor pattern 3 and the via hole 4 are formed) is the second region, and is a region where the electrical connection function is not provided. A certain peripheral portion 11 is set as a first region. One multilayer substrate 20 is formed from the laminate 10.
[0044]
The 2nd buffer member 50 is formed using the material which can exhibit a buffer effect like the 1st buffer member 40, and as shown in Drawing 3 (a), it is in the shape of peripheral part 11 of layered product 10. Correspondingly, it is provided in an annular shape. Moreover, if the peripheral part 11 of the laminated body 10 is compressed too much (when a high pressurizing force is applied too much), the resin of the peripheral part 11 flows in the reverse direction toward the central part 12, and is positioned on the conductor pattern 3 in the vicinity of the peripheral part 11. There is a risk of deviation. Accordingly, the second buffer member 50 is formed with a thickness and a hardness that do not cause displacement in the conductor pattern 3 in the central portion 12 due to the reverse flow of the resin. In the present embodiment, a non-woven Naslon (registered trademark) felt material is used as the second buffer member 50. FIG. 3A is a plan view for explaining the second buffer member 50.
[0045]
When the second buffer member 50 is arranged and pressed by the hot press plate 30 having a flat press surface, the peripheral portion 11 of the laminate 10 is the central portion by the thickness of the second buffer member 50. The pressure is applied earlier than 12, and the resin in the peripheral portion 11 is compressed first. Moreover, since the pressurizing force which the peripheral part 11 of the laminated body 10 receives from the hot press board 30 increases by arrange | positioning the 2nd buffer member 50, the deformation amount (resin compression amount) of the peripheral part 11 is the center part 12. It becomes larger than the deformation amount. Therefore, the flow of resin from the central portion 12 of the laminated body 10 toward the peripheral portion 11 (the planar direction of the single-sided conductor pattern film 1) is suppressed by the same effect as the so-called packing. That is, according to the manufacturing method of the multilayer substrate 20 shown in the present embodiment, it is possible to reduce the displacement of the conductor pattern 3 due to the resin flow in the planar direction. In addition, as for the heating and pressurizing conditions applied to the laminated body 10 by the hot press plate 30, for example, the temperature is a value in the range of 200 to 350 ° C., and the pressure is a value in the range of 0.1 to 10 MPa.
[0046]
In the present embodiment, the deformable second buffer member 50 is used as the auxiliary pressure member. Therefore, as shown in the schematic cross-sectional view of FIG. 4, a part of the second buffer member 50 is in contact with the side surface of the laminate 10 during heating and pressurization, and becomes a resistance against the flow of the softened resin in the planar direction. Is also possible. The part corresponding to the peripheral part 11 of the laminated body 10 in the second buffer member 50 is compressed and deformed between the peripheral part 11 of the laminated body 10 and the first buffer member 40 under the pressure from the hot press plate 30. While being applied, a higher pressing force than the central portion 12 is transmitted to the peripheral portion 11 of the laminate 10.
[0047]
On the other hand, in the second buffer member 50, the extending portion 51 extending in the direction opposite to the central portion 12 from the portion corresponding to the peripheral portion 11 of the laminated body 10 is a target to which the pressure from the hot press plate 30 is to be transmitted. Therefore, the material is not compressed and deformed, and extends along the side surface of the laminated body 10 and comes into contact with the side surface of the laminated body 10. And it becomes resistance with respect to the flow to the plane direction of the softened resin. Thus, when the 2nd buffer member 50 has the extension part 51, since the flow of the resin to the plane direction in the laminated body 10 can be further suppressed, it is preferable. In FIG. 4, the side surfaces of the laminated body 10 are closed from the upper surface to the lower surface by the two extending portions 51 of the second buffer member 50 disposed on both surfaces of the laminated body 10. The extending portion 51 of the second buffer member 50 provided on the surface of one laminate 10 may be in contact from the upper surface to the lower surface of the side surface of the laminate 10.
[0049]
Moreover, in this Embodiment, the 2nd buffer member 50 showed the example provided cyclically | annularly as shown to Fig.3 (a). However, it may be formed with a predetermined gap 52 as shown in FIG. However, since the softened resin flows out from the second region through the gap 52 as the gap 52 is larger, it is preferably provided in an annular shape as shown in FIG. FIG. 3B is a plan view showing a modification of FIG.
[0050]
Moreover, in this Embodiment, as shown in FIG. 2, the example which arrange | positions the 2nd buffer member 50 between the laminated body 10 and the 1st buffer member 40 was shown. However, it may be disposed between the first buffer member 40 and the hot press plate 30.
[0051]
  Moreover, in this Embodiment, although the 2nd buffer member 50 showed the example provided on both surfaces of the laminated body 10, you may provide only in any one. In addition, an example in which the first buffer member 40 is also provided on both surfaces of the laminated body 10 is shown. However,The first buffer member 40 may be provided only on one of the surfaces..
[0052]
Further, the multilayer substrate 20 formed by the manufacturing method shown in the present embodiment has the same number of laminated resin films 2 in the peripheral portion 11 and the central portion 12, but as shown in FIG. The portion 11 (the portion on the side surface side from the broken line) has a thinner shape than the central portion 12. In addition, a region that does not provide an electrical connection function is a peripheral portion 11, and a region that provides an electrical connection function is a central portion 12. Therefore, it is also possible to identify the multilayer substrate 20 of the present invention from its appearance and cross-sectional shape.
[0053]
In the present embodiment, since the peripheral portion 11 is designed in advance as an unnecessary region that does not provide an electrical connection function, the peripheral portion 11 may be deleted in the deletion step after the multilayer substrate 20 is formed. .
[0054]
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic cross-sectional view for explaining the heating / pressurizing step in the present embodiment, and corresponds to FIG. 2 of the first embodiment.
[0055]
Since the manufacturing method of the multilayer substrate 20 in the second embodiment is often the same as that in the first embodiment, the detailed description of the common parts will be omitted below, and different parts will be mainly described. .
[0056]
The second embodiment is different from the first embodiment in that a pressure assisting member is integrally provided as a part of the first buffer member 40.
[0057]
As shown in FIG. 5, the pressure assisting member in the present embodiment is a first buffering member corresponding to the peripheral portion 11 of the laminate 10 as a part of the first buffering member 40 (pressurizing assisting part 41). It is provided integrally at 40 sites.
[0058]
The pressure assisting part 41 is made of the same material as that of the first buffering member 40, and the site where the pressure assisting part 41 is formed in the first buffering member 40 is different from other parts of the first buffering member 40. Also has a thickness. In addition, as shown in FIG. 5, the first buffer member 40 is disposed between both surfaces of the laminate 10 and the hot press plate 30 corresponding thereto, and the pressure assisting portion 41 is provided from the first buffer member 40. It has a structure protruding in the direction of the opposing first buffer member 40.
[0059]
When the first buffer member 40 having such a pressurizing assisting portion 41 is disposed between the hot press plate 30 and the laminate 10 and pressed by the hot press plate 30 having a flat press surface, the laminate Ten peripheral portions 11 are pressurized faster than the central portion 12, and the resin in the peripheral portions 11 is compressed first. Moreover, since the pressurization auxiliary | assistant part 41 formation site | part of the 1st buffer member 40 has thickness rather than another site | part, the pressurization force which the peripheral part 11 of the laminated body 10 receives from the hot press board 30 increases, The deformation amount of the peripheral portion 11 is larger than the deformation amount of the central portion 12. Accordingly, as in the first embodiment, the resin flow from the central portion 12 of the laminate 10 toward the peripheral portion 11 (plane direction) is suppressed. That is, also by the manufacturing method of the multilayer substrate 20 shown in the present embodiment, it is possible to reduce the displacement of the conductor pattern 3 due to the flow of the resin in the planar direction.
[0060]
In the present embodiment, the pressure assisting portion 41 (having the first buffer member 40) extends in a direction corresponding to the peripheral portion 11 of the laminate 10 and the central portion 12 extending in the opposite direction from the portion. It is preferable that it is comprised by a part. When the pressure from the hot press plate 30 is received, the extension portion comes into contact with the side surface of the laminate 10 and becomes a resistance against the flow of the resin in the plane direction, thereby further suppressing the resin flow in the plane direction. can do.
[0061]
Further, in the present embodiment, the pressure assisting part 41 may be provided in an annular shape according to the shape of the peripheral part 11, and, like the second buffer member 50 shown in the first embodiment, a predetermined gap May be provided. However, it is more effective to suppress the flow of the resin in the plane direction when the ring is provided.
[0062]
Moreover, in this Embodiment, as shown in FIG. 5, the 1st buffer member 40 was arrange | positioned on both surfaces of the laminated body 10, and the example which the pressurization auxiliary | assistance part 41 has was shown, respectively. However, the pressure assisting part 41 may be provided only on one first buffer member 40. Further, the first buffer member 40 may be disposed only on one surface of the laminated body 10, and the first buffer member 40 may include the pressure assisting portion 41.
[0063]
Further, in the present embodiment, as shown in FIG. 5, the pressure assisting portion 41 protrudes from the first buffer member 40 toward the first buffer member 40, and other parts of the first buffer member 40. The example provided with more thickness was shown. However, since the 1st buffer member 40 has flexibility, it does not need to protrude in the 1st buffer member 40 direction which opposes. For example, the pressure assisting part 41 may have a structure that protrudes in the direction of the hot press plate 30 with which the first buffer member 40 is in contact with the first buffer member 40 while being thicker than other parts. In this case, the effect of suppressing the flow of the resin due to the peripheral portion 11 of the laminate 10 being compressed faster than the central portion 12 is not obtained, but the first buffer member 40 has flexibility and is pressurized. Since the auxiliary part 41 formation site is thick, a higher pressing force is applied to the peripheral part 11 of the laminated body 10 than the central part 12, and the amount of deformation increases. Therefore, resin flow in the planar direction can be suppressed.
[0064]
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic cross-sectional view for explaining the heating / pressurizing step in the present embodiment, and corresponds to FIG. 2 of the first embodiment.
[0065]
Since the manufacturing method of the multilayer substrate 20 in the third embodiment is often in common with that in the first embodiment, the detailed description of the common parts will be omitted below, and different parts will be described mainly. .
[0066]
The third embodiment is different from the first embodiment in that the pressure auxiliary member is a resin film laminated on the surface of the laminate 10.
[0067]
The pressurizing auxiliary member in the present embodiment is an annular resin film 51 having a shape corresponding to the peripheral portion 11 of the laminate 10, and is formed by laminating four layers of the single-sided conductor pattern film 1 as shown in FIG. 6. Laminated on both surfaces of the laminate 10.
[0068]
The resin film 51 may be the same thermoplastic resin as the resin film 2 constituting the single-sided conductor pattern film 1, or may be another thermoplastic resin or a thermosetting resin. However, if a resin that softens during heating and pressurization is used, the resin film 51 itself softens and flows in the plane direction of the laminate 10. In order to apply a higher pressing force to the peripheral portion 11 of the laminated body 10 than the central portion 12, a certain thickness is required in anticipation of the flow. Therefore, it is better to use as the resin film 51 a resin that does not soften during heating and pressurization.
[0069]
When such a resin film 51 is laminated on the surface of the laminate 10 and pressed by the hot press plate 30 having a flat press surface, the peripheral portion 11 of the laminate 10 is pressed faster than the central portion 12, The resin of the part 11 is compressed first. Further, since the resin film 51 has a predetermined thickness, the pressure applied to the peripheral portion 11 of the laminate 10 from the hot press plate 30 is increased, and the deformation amount of the peripheral portion 11 is larger than the deformation amount of the central portion 12. growing. Accordingly, as in the first embodiment, the resin flow from the central portion 12 of the laminate 10 toward the peripheral portion 11 (plane direction) is suppressed. That is, also by the manufacturing method of the multilayer substrate 20 shown in the present embodiment, it is possible to reduce the displacement of the conductor pattern 3 due to the flow of the resin in the planar direction.
[0070]
Also in this embodiment, the resin film 51 is constituted by a portion corresponding to the peripheral portion 11 of the laminate 10 and an extending portion extending from the portion in the direction opposite to the central portion 12, and from the hot press plate 30. It is preferable that the extended portion is formed of a material that can come into contact with the side surface of the laminate 10 when subjected to pressure. Since the extension portion becomes a resistance against the flow of the resin in the plane direction, the flow of the resin in the plane direction can be further suppressed.
[0071]
In the present embodiment, the example in which the resin film 51 is provided in an annular shape has been described. However, like the second buffer member 50 shown in the first embodiment, the resin film 51 may be formed with a predetermined gap.
[0072]
Moreover, in FIG. 6, the example in which the resin film 51 is provided on both surfaces of the laminated body 10 was shown. However, the resin film 51 may be laminated only on at least one surface of the laminate 10.
[0073]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a schematic cross-sectional view for explaining the heating / pressurizing process in the present embodiment, and corresponds to FIG. 2 of the first embodiment.
[0074]
Since the manufacturing method of the multilayer substrate 20 in the fourth embodiment is often in common with that in the first embodiment, the detailed description of the common parts will be omitted below, and different parts will be described mainly. .
[0075]
The fourth embodiment is different from the first embodiment in that the pressure auxiliary member is integrally provided as a part of the hot press plate 30.
[0076]
As shown in FIG. 7, the hot press plate 30 of the present embodiment is an annular pressurization projecting in the direction of the laminate 10 in the portion corresponding to the peripheral portion 11 of the laminate 10 than in the portion corresponding to the central portion 12. An auxiliary part 31 is provided.
[0077]
When the laminated body 10 is pressurized using the hot press plate 30 having such a pressure assisting part 31, the peripheral part 11 of the laminated body 10 is pressurized faster than the central part 12, and the resin in the peripheral part 11 is first. Is compressed. Further, the pressure applied to the peripheral portion 11 of the laminated body 10 from the hot press plate 30 is increased by the thickness of the pressure assisting portion 31, and the deformation amount of the peripheral portion 11 becomes larger than the deformation amount of the central portion 12. Accordingly, as in the first embodiment, the resin flow from the central portion 12 of the laminate 10 toward the peripheral portion 11 (plane direction) is suppressed. That is, also by the manufacturing method of the multilayer substrate 20 shown in the present embodiment, it is possible to reduce the displacement of the conductor pattern 3 due to the flow of the resin in the planar direction.
[0078]
In the present embodiment, the example in which the pressure assisting portion 31 is provided in an annular shape has been described. However, like the second buffer member 50 shown in the first embodiment, it may be formed with a predetermined gap.
[0079]
Moreover, in this Embodiment, as shown in FIG. 7, the example in which the pressurization assistance part 31 is provided in both of a pair of hot press board 30 was shown. However, it goes without saying that the pressure auxiliary portion 31 may be formed only on one of the hot press plates 30.
[0080]
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made.
[0081]
In the present embodiment, the resin film is a thermoplastic resin film composed of 65 to 35% PEEK resin and 35 to 65% PEI resin, but PEEK and PEI can be used alone. Furthermore, polyethersulfone (PES), polyphenylene ether (PPE), polyethylene naphthalate (PEN), liquid crystal polymer, styrenic resin having a syndiotactic structure or the like may be used alone, or PEEK and PEI may be used. Any one of them may be mixed and used. In short, in the heating / pressurizing step, resin films can be bonded to each other, and any resin film having heat resistance necessary for soldering or the like, which is a subsequent step, can be suitably used.
[0082]
Moreover, in this Embodiment, although the example which laminates | stacks the single-sided conductor pattern film in which the conductor pattern was formed on one side was shown as a resin film, a single-sided conductor pattern film is arrange | positioned on the upper and lower sides using a core board | substrate other than that Alternatively, a processed resin film made of a thermoplastic resin having a conductor pattern formed on both sides may be used instead of the core substrate. Moreover, in the resin film laminated | stacked, you may include the resin film which does not have a conductor pattern on the surface.
[0083]
In the present embodiment, an example of a printing method in which a conductive paste is filled in a via hole is shown. However, electroless plating, electrolytic plating, vapor deposition, metal coating, or the like may be used.
[0084]
Further, in the present embodiment, a bottomed via hole is formed, and the bottomed via hole is filled with a conductive paste which is an interlayer connection material. A through hole is formed at the time of forming the via hole, and the interlayer connection material is formed in the through via hole. May be used.
[0085]
Moreover, in this Embodiment, although the example which laminates | stacks four single-sided conductor pattern films containing a resin film was shown, it cannot be overemphasized that the number of layers will not be limited if it is two or more.
[0086]
Moreover, in this Embodiment, as a specific example of the heating / pressurizing condition of the first region that suppresses the flow of resin from the second region (central portion) to the first region (peripheral portion) of the laminate. An example in which a pressure assisting member (or a pressure assisting part) is disposed between the first region of the laminate and the hot press plate has been shown. However, the heating / pressurizing conditions are not limited to the above examples. In addition, the first region of the laminate may be pressurized with a higher pressing force than the second region. For example, the heat press plate may be divided and the portion corresponding to the peripheral portion of the laminate may be set to a higher pressure than the portion corresponding to the central portion, and the first region and the second region may be pressurized simultaneously. In this case, since the first region of the laminate that has received a high pressure is compressed more than the second region, the flow of resin from the second region toward the first region can be suppressed.
[0087]
Moreover, you may pressurize the 1st area | region of a laminated body with the pressurization start timing earlier than a 2nd area | region. Even if the pressure applied to the first region and the second region is the same, the resin in the first region is already compressed when the resin in the second region flows by pressurizing the first region first. Then, the flow of resin from the second region toward the first region can be suppressed.
[0088]
Moreover, it is good also as a heating and pressurizing condition that the deformation amount of the 1st area | region by pressurization becomes larger than the deformation amount of a 2nd area | region. A large amount of deformation due to pressurization means that the amount of compression of the resin in the stacking direction is large. That is, since the resin in the first region is compressed more than in the second region, the flow of resin from the second region toward the first region can be suppressed.
[0089]
Moreover, all the above-mentioned heating and pressurizing conditions suppressed the flow of resin from the second region toward the first region by changing the pressurizing conditions. However, the flow of the resin may be suppressed by changing the heating conditions. For example, by heating the first region at a lower heating temperature than the second region, the flow amount of the resin in the first region is made smaller than the flow amount of the resin in the second region, and the flow of the resin in the second region is reduced. Can be suppressed. At that time, the heating temperature in the first region may be a temperature at which the resin in the first region does not undergo plastic deformation.
[0090]
In the present embodiment, the first buffer member and the second buffer member are provided so as to be deformable in accordance with the surface irregularities of the laminate in order to exert a buffering effect. It may be difficult to peel off from the hot press plate. Therefore, a release sheet made of polyimide or the like is preferably disposed between the first buffer member and / or the second buffer member and another member (laminated body, hot press plate) in contact with the buffer member. In that case, you may arrange | position a release sheet so that the whole buffer member may be wrapped.
[Brief description of the drawings]
FIGS. 1A and 1B are cross-sectional views showing a manufacturing process of a multilayer substrate in a first embodiment of the present invention, where FIG. 1A is a conductor pattern formation, FIG. 1B is a via hole formation, and FIG. 1C is an interlayer connection material filling; (D) is a lamination process, (e) is a figure which shows the multilayer substrate after a heating and pressurizing process.
FIG. 2 is a schematic cross-sectional view for explaining a heating / pressurizing step in the first embodiment.
FIG. 3 is a supplementary view for explaining the shape of a second buffer member, where (a) is a plan view and (b) is a plan view showing a modification of (a).
FIG. 4 is a schematic cross-sectional view for explaining the effect of a second buffer member.
FIG. 5 is a schematic cross-sectional view for explaining a heating / pressurizing step in the second embodiment.
FIG. 6 is a schematic cross-sectional view for explaining a heating / pressurizing step in the third embodiment.
FIG. 7 is a schematic cross-sectional view for explaining a heating / pressurizing step in the fourth embodiment.
[Explanation of symbols]
2 ... Resin film
3 ... Conductor pattern
10 ... Laminated body
11 ... Peripheral part
12 ... Central part
20 ... Multilayer substrate
30 ... Hot press plate
40: First buffer member
50: Second buffer member

Claims

A laminating step of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers to form a laminate;
By pressurizing with heating across the stack by a pair of hot press plates, a method of manufacturing the multilayer board Ru and a heat-pressing step of forming a multilayer substrate by bonding the resin film to each other And
In the heating / pressurizing step,
Between the laminate surface and the hot press plate, a first buffer member that transmits pressure force from the hot press plate to the laminate while being deformed according to the unevenness of the laminate surface is disposed, In the state where a second buffer member as a pressure assisting member that deforms in accordance with the unevenness of the surface of the laminate is disposed between the peripheral portion of the laminate and the hot press plate, the laminate is formed by the hot press plate. By applying pressure while heating the body, the heating and pressurizing conditions in the peripheral part of the laminate and the central part surrounded by the peripheral part have a difference,
The first buffer member and the second buffer member have a size that extends from the end of the laminated body in the direction opposite to the central portion, and thereby the first press member is pressed by the hot press plate. A method of manufacturing a multilayer substrate, comprising deforming the buffer member or the second buffer member and bringing a part of the buffer member into contact with a side surface of the laminate .

The second buffer member is disposed between the stacked body and the first buffer member,
The method for producing a multilayer substrate according to claim 1 , wherein a part of the second buffer member is brought into contact with a side surface of the multilayer body by pressurization of the hot press plate .

The second buffer member is disposed between the first buffer member and the hot press plate,
The method for producing a multilayer substrate according to claim 1, wherein a part of the first buffer member is brought into contact with a side surface of the multilayer body by pressurization of the hot press plate .

A laminating step of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers to form a laminate;
A method for producing a multilayer substrate comprising: a heating / pressurizing step for bonding the resin films to each other to form a multilayer substrate by pressing the laminated body while being sandwiched between a pair of hot press plates and heating. ,
In the heating / pressurizing step,
In a state where a first buffer member is disposed between the surface of the laminate and the hot press plate, and the first buffer member transmits pressure from the hot press plate to the laminate while being deformed according to the unevenness of the surface of the laminate. , While pressurizing while heating the laminate by the hot press plate,
A pressure assisting member made of the same material as that of the first buffering member is integrally provided at a portion corresponding to the peripheral portion of the laminate in the first buffering member, and the pressure assisting member is thicker than other portions. By having a part, the heating and pressurizing conditions in the peripheral part of the laminate and the central part surrounded by the peripheral part have a difference,
By changing the size of the first buffer member from the end of the laminated body in the direction opposite to the central portion, the first buffer member is deformed by pressurization of the hot press plate, A method for producing a multilayer substrate, wherein a part thereof is brought into contact with a side surface of the laminate .

A laminating step of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers to form a laminate;
A method for producing a multilayer substrate comprising: a heating / pressurizing step for bonding the resin films to each other to form a multilayer substrate by pressing the laminated body while being sandwiched between a pair of hot press plates and heating. ,
In the heating / pressurizing step,
Between the laminate surface and the hot press plate, a first buffer member that transmits pressure force from the hot press plate to the laminate while being deformed according to the unevenness of the laminate surface is disposed, In a state where a pressurizing auxiliary member made of a resin film that does not soften during heating and pressurization is disposed between the peripheral portion of the laminate and the hot press plate, the hot press plate is pressed while heating the laminate. By giving a difference in the heating and pressure conditions in the peripheral part of the laminate and the central part surrounded by the peripheral part,
The first pressurizing member has a size extending from the end of the laminate in the direction opposite to the central portion, and is disposed between the laminate and the pressure assisting member, so that the hot press A method for producing a multilayer substrate, comprising: deforming the first buffer member by pressurizing a plate; and contacting a part of the first buffer member with a side surface of the laminate .

A laminating step of laminating a resin film made of a thermoplastic resin and a conductive pattern made of a conductive material in multiple layers to form a laminate;
A method for producing a multilayer substrate comprising: a heating / pressurizing step for bonding the resin films to each other to form a multilayer substrate by pressing the laminated body while being sandwiched between a pair of hot press plates and heating. ,
In the heating / pressurizing step,
In a state where a first buffer member is disposed between the surface of the laminate and the hot press plate, and the first buffer member transmits pressure from the hot press plate to the laminate while being deformed according to the unevenness of the surface of the laminate. , While pressurizing while heating the laminate by the hot press plate,
By providing a pressure assisting member integrally at a portion corresponding to the peripheral portion of the laminate in the hot press plate and forming a pressure assisting portion projecting toward the laminate from the other portion, Have a difference in heating and pressurizing conditions in the peripheral part and the central part surrounded by the peripheral part,
By setting the first buffer member to a size that extends in the direction opposite to the center portion from the end of the laminate, a part of the first buffer member is formed by pressing the hot press plate. A method for producing a multilayer substrate, comprising contacting the side surface of the laminate .

The method for manufacturing a multilayer substrate according to claim 1, wherein the pressure assisting member is provided in an annular shape corresponding to a peripheral portion of the multilayer body .

The peripheral portion is a region that does not provide an electrical connection function as the multilayer substrate, and the central portion is a region that provides an electrical connection function as the multilayer substrate. 7. The method for producing a multilayer substrate according to any one of 7 above .

9. The method for manufacturing a multilayer substrate according to claim 1, further comprising a deletion step of deleting a peripheral portion of the formed multilayer substrate after the heating / pressurizing step.