JP2005032931A

JP2005032931A - Substrate, manufacturing method thereof, and electronic circuit device

Info

Publication number: JP2005032931A
Application number: JP2003195311A
Authority: JP
Inventors: Yuichi Tagami; 雄一田上
Original assignee: Toshiba Corp; Toshiba Electronic Engineering Co Ltd
Current assignee: Toshiba Corp; Toshiba Development and Engineering Corp
Priority date: 2003-07-10
Filing date: 2003-07-10
Publication date: 2005-02-03

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate, a manufacturing method thereof, and an electronic circuit device with which short-circuiting between adjacent conductors and failures in junction between an electric component and a land can be suppressed. <P>SOLUTION: The substrate 1 is equipped, on the principal plane of an insulation substrate 11, with a land 14 and a conductor 12 having a circuit wiring portion 13 connecting with the land 14. The surfaces of the conductor 12 and the insulation substrate 11 are covered with an insulating resin 16, and an opening is provided on the insulating resin 16 on the land 14 to have the land 14 exposed through the opening. A protrusion 15 protruding upward from the surface of the resin 16 in the vicinity is formed on the upper surface of the land 14. The electrode of the electric component is joined with the upper surface of the protrusion 15 of the land 14 via solder. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、回路基板、回路基板の製造方法及び電子回路装置に関し、特に高周波で機能する回路基板、回路基板の製造方法及び電子回路装置に関する。
【０００２】
【従来の技術】
近年、情報通信分野や情報処理分野の電子機器は高速化、小型化、高機能化等を目指して発展しており、とりわけ、画像等大量の情報を伝送する分野等においては高速化要求が高く、そこに使われる電子回路装置用の回路基板は、加工の精密化、多層化等が進められている。
【０００３】
現在、回路基板は、導電体からなる配線層が絶縁部材によって囲繞されたり、埋め込まれた構造となっている。半導体部品や抵抗体及びコンデンサー等のチップ部品（以下、単に電気部品という）が、露出した配線層に載置されて、ハンダ等を介して電気的な接続がなされる。薄板形状の絶縁部材と配線層とを複数枚交互に重ねて、多層の回路を１枚の回路基板に形成した多層基板も広く用いられており、そこでは、導電体は、配線として他の部品やグランド等に３次元的に接続されている。
【０００４】
これらの回路基板は、材料、用途等により、例えば銅板を絶縁性の板材に貼着して、必要な配線部をマスキングして不要な銅を薬品処理等でエッチング除去して回路を形成する方法、配線部を銅メッキ等で作成する方法、あるいは、絶縁部材の上に導電性のペースト材を配線の形に印刷した後、焼き固めて作製する方法等で作製される。また、導電体配線を絶縁性樹脂で固める方法も提案されている。これらの回路基板では導電体の表面は高低のない同一面で形成される。
【０００５】
従来の回路基板について、図９を参照しながら説明する。図９（ａ）は回路基板の要部を示す断面図、図９（ｂ）はこの回路基板に部品を実装した状態を模式的に示す図である。図９には、単層の回路基板、あるいは、多層回路基板の場合ではその最も外側の表面部を表している。
【０００６】
図９（ａ）に示すように、回路基板５は、絶縁基板１０１上に回路配線部１０３及びランド１０４からなる導電体１０２が固着されており、絶縁基板１０１上にはハンダの流出防止や導電体間の絶縁のために導電体１０２を覆うように絶縁性樹脂（絶縁層）１０６が形成されており、ランド１０４上の絶縁性樹脂１０６には開口部が形成されており、ランド１０４は開口部から部分的に露出されている。
【０００７】
従って、通常、回路基板５においては、ランド１０４上面は絶縁性樹脂１０４の厚さ分だけ低く窪んでいる。
【０００８】
そして、図９（ｂ）に示すように、この回路基板５には、ランド１０４上面にハンダを印刷等で形成した後、電気部品１２１の電極部１２２を回路基板５のランド１０４に位置合わせし、リフロー等によりハンダ１０７を溶融して、固化することによって、電気部品１２１の電極１２２とランド１０４とをハンダ接続して電子回路装置を作製している（例えば、特許文献１参照。）。
【０００９】
上述した従来の回路基板においては、ランド１０４上面は絶縁性樹脂１０４の層厚分だけ低いため、電気部品１２１の電極部１２２とランド１０３との間には絶縁性樹脂１０４の層厚に相当する空間が生じる。従って、回路基板５のランド１０４に電気部品１２１をハンダ実装する場合、ハンダ接続はハンダ１０７の量に左右されることになる。すなわち、ハンダ１０７が絶縁性樹脂１０６の層厚より多量に塗布された場合は、ハンダ過多となって、接合に寄与しないハンダボールの発生やハンダの流出等が起こり、隣接する導電体１０２間のショートが発生することになる。逆に、ハンダ１０７が絶縁性樹脂１０６の層厚相当より少なく塗布された場合は、電気部品の電極部１２２とランド１０４とが接合不良となる問題が発生する。特に、電極部と外囲器とが平坦で同一面をなす電気部品においては、ショート、接合不良等の実装ばらつきが発生する。
【００１０】
【特許文献１】
特開平８−３３０７１５号公報（第２頁、図２）
【００１１】
【発明が解決しようとする課題】
上述したように、従来の回路基板によれば、絶縁性樹脂表面がランド上面よりも高い位置に形成されているため、ハンダが多過ぎる場合、ハンダボールの発生やハンダの流出による隣接の導電体間のショートが発生する。逆に、ハンダの量が少な過ぎると、電気部品と導電体との接合不良が発生する等の問題がある。
【００１２】
従って、本発明は、上記問題に鑑みてなされたもので、隣接の導電体間のショート、導電体と電気部品と接合不良を抑制できる回路基板、回路基板の製造方法及び電子回路装置を提供することを目的とする。
【００１３】
【課題を解決するための手段】
上記目的を達成するために、本発明の一態様の回路基板は、絶縁基板と、前記絶縁基板の主面に固着されたランド及びこのランドに連接された回路配線部を有する導電体と、前記ランドを少なくとも露出して前記導電体及び前記絶縁基板表面覆う絶縁層と、前記ランド上面に形成され、且つこのランド近傍の前記絶縁層表面より上方に突出する突出部とを有することを特徴とする。
【００１４】
また、本発明の他の態様の回路基板の製造方法は、絶縁基板の主面にランド及びこのランドと連接した回路配線部を有する導電体を形成する工程と、前記ランド上面の少なくとも一部を残してそれ以外の前記導電体表面をエッチング除去して前記ランド上面に突出部を形成する工程と、前記突出部上面を少なくとも露出し、且つ前記導電体及び前記絶縁基板表面を前記突出部の高さより小さい層厚を有する絶縁層で覆う工程とを有することを特徴とする。
【００１５】
また、本発明の他の態様の電子回路装置は、絶縁基板主面にランド及びこのランドと連接された回路配線部を有する導電体が形成され、前記ランド上面に前記回路配線部上面より突出した突出部が形成され、前記突出部を少なくとも露出して前記導電体及び前記絶縁基板の表面が前記突出部の高さより小さい層厚の絶縁層で覆われた回路基板と、前記回路基板の前記突出部上面に接合材を介して接合された電気部品とを有することを特徴とする。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照しながら説明する。
【００１７】
（第１の実施の形態）
先ず、本発明の第１の実施の形態に係る回路基板、回路基板の製造方法及び電子回路装置について、図面を参照して説明する。
【００１８】
図１は、本発明の第１の実施の形態に係る回路基板の要部を模式的に示す断面図及び平面図である。回路基板には、絶縁基板が１枚の単層基板、及び、絶縁基板と配線層が複数積層した多層基板があるが、ここでは、多層基板の場合には最上層にある１層の絶縁基板と１層の導電体層の部分を示す。また、電気部品を実装するランド部分とその周辺を示す。
【００１９】
まず、図１（ａ）、（ｂ）に示すように、回路基板１は、ＢＴレジン（ビスマレイミド・トリアジン、三菱瓦斯化学（株））、エポキシ系樹脂、あるいはセラミック等を使用する可撓性が小さくリジッドな絶縁基板１１を有する。この絶縁基板１１の表面には、銅等からなるパターニングされた配線層となる導電体１２が設けられている。この導電体１２は、所定の回路機能を構成するための回路配線部１３とこれと連接形成されて電気部品を接続するためのランド１４とを有し、例えば３０μｍ程度の厚さに形成されている。
【００２０】
回路配線部１３は、他の電気部品やグランド等と接続するために、単層回路基板の場合には絶縁基板１１の表面部において、また多層回路基板の場合には表面部または内部において、他の導電体の回路配線部と接続されている。
【００２１】
この絶縁基板１１上には、絶縁層としての絶縁性樹脂１６が導電体１２を覆うように形成されて、導電体１２同士を絶縁分離、及び、電気部品の実装時にハンダ等の接合材が不用意に広がって、隣接する導電体１２間のショートが生じないようにするためのマスク層として機能する。この絶縁性樹脂１６は、耐熱性のあるポリイミド樹脂やエポキシ樹脂等からなり、導電体１２上で５μｍ程度の層厚に形成されている。
【００２２】
ランド１４上の絶縁性樹脂１６には、開口部が形成されており、ランド１４は、開口部から部分的に露出されている。このランド１４の露出面の一部には、絶縁性樹脂１６の表面より上方に突出した突出部１５が形成されている。
【００２３】
次に、この回路基板の製造方法の１例について、図２を参照して説明する。図２は、上記構造の回路基板の製造方法を工程順に模式的に示す断面図である。
【００２４】
まず、図２（ａ）に示すように、絶縁基板１１上面に最終的に導電体１２となる銅箔１２ａを貼り付ける。
【００２５】
次に、図２（ｂ）に示すように、銅箔１２ａ上にフォトレジストを塗布して、露光、現像、エッチング等のフォトエッチング法により、フォトレジストをパターニングして所定パターンの導電体を形成するための開口部２０を有するマスクパターン１８を設ける。
【００２６】
次に、図２（ｃ）に示すように、マスクパターン１８をマスクにして、例えば、銅箔１２ａ上にホット塩化第二鉄水溶液をスプレー、または、図２（ｂ）の絶縁基板１１をホット塩化第二鉄水溶液にディッピングして、開口部２０から銅箔１２ａを絶縁基板１１に到達するまでエッチングして分離溝２５を形成した後、マスクパターン１８を除去して、分離溝２５により絶縁分離された所定パターンの導電体１２を形成する。
【００２７】
次に、図２（ｄ）に示すように、導電体１２上にフォトレジストを塗布して、図２（ｂ）と同様に、露光、現像、エッチング等のフォトエッチング法により、ランド１４上面の突出部１５となる位置にマスクパターン１９を形成する。
【００２８】
次に、図２（ｅ）に示すように、マスクパターン１９をマスクにして、例えば、導電体１２上にホット塩化第二鉄水溶液をスプレー、または、図２（ｄ）の絶縁基板１１をホット塩化第二鉄水溶液にディッピングして、露出している導電体１２を、図２（ｆ）に示す絶縁性樹脂１６の層厚より深くなるようにエッチングする。その後、マスクパターン１９を除去し、ランド１４上に上面が平坦な突出部１５を有する導電体１２を形成する。
【００２９】
この後、導電体１２の回路配線部１３及び突出部１５を含むランド１４等の露出部分上には、接合性向上や腐食防止のために、ニッケル等のメッキが施される。
【００３０】
そして、図２（ｆ）に示すように、ランド１４部分を残してそれ以外の導電体１２表面を覆うように、また、隣り合う導電体１２間の分離溝２５を埋めるように、例えば、ポリイミド等からなる絶縁性樹脂１６をマスクキング印刷法等で絶縁基板１１上に形成する。この絶縁性樹脂１６は、突出部１５上面より５μｍ程度低くなるような層厚に形成する。
【００３１】
なお、絶縁性樹脂１６は、導電体１２を覆うように、例えば感光性ポリイミド等の感光性樹脂を絶縁基板１１上全面に塗布し、通常の露光、現像、エッチング等のフォトエッチング法により、ランド１４上に開口部を設けてもよい。
【００３２】
この結果、電気部品のマウント実装されるランド１４の突出部１５が、この近傍の絶縁性樹脂１６の表面より５μｍ程度高い回路基板１が得られる。
【００３３】
図３は、上記回路基板に電気部品をハンダ実装してなる電子回路装置を模式的に示す断面図である。
【００３４】
図３に示すように、回路基板１の突出部１５を含むランド１４には、接合材、例えばハンダ１７はマスク等を使用した印刷法等で所定量形成される。このランド１４の突出部１５上には、電極部１２２と外囲器とが平坦、且つ同一平面を有する電気部品１２１の電極部１２２が位置合わせ、載置され、ハンダ１７をリフロー法で溶融させた後、固化させることによって、電気部品１２１の電極部１２２がランド１４に接合されている。
【００３５】
上述した実施の形態の回路基板１によれば、ランド１４に絶縁性樹脂１６表面より上方に突出した突出部１５を設け、この突出部１５の上面に電気部品１２１を実装するようにしている。従って、電気部品１２１は絶縁性樹脂１６との間に５μｍ程度の隙間を維持して固定されるため、電気部品１２１の電極部１２２とランド１４とは確実に接合される。このため、電気部品１２１とランド１４とを接合するハンダ１７の塗布量が少なくなるため、高周波特性の向上を図ることができる。
【００３６】
また、電気部品１２１と絶縁性樹脂１６との隙間２６は、余分なハンダの逃げる余地を与えることになり、余分なハンダがランド１４に接着した状態を維持できるので、ハンダボールとして移動して隣接の導電体１２間のショートを起こす等の不良発生を抑制できる。従って、従来の回路基板におけるハンダ不足による接合不良やハンダ過多による隣接の導電体間のショート等を防止できる。
【００３７】
更に、電気部品１２１と絶縁性樹脂１６との間に隙間２６を有するため、セルフアラインメント効果が期待できる。すなわち、溶融したハンダ１７の表面張力によって電気部品１２１がランド１４における突出部１５の中心部に戻ろうとして移動するために、電気部品１２１の再配置が起こり、適正な位置に実装される。従って、電気部品１２１は回路基板１のパターンに基づく一定の位置に固定されるために、電気的特性、特に高周波特性の安定化を図ることができる。
【００３８】
更にまた、電気部品１２１と絶縁性樹脂１６との間に隙間２６を有するため、電気部品１２１のハンダ接合工程で使用されるフラックスや、ハンダ接合後の洗浄工程における洗浄剤の残留を防止することができる。従って、長時間を経て起こる電気部品や導電体の変質を抑制でき、電子回路装置の長期にわたる信頼性を確保することができる。
【００３９】
（第２の実施の形態）
次に、本発明の第２の実施の形態に係る回路基板、回路基板の製造方法及び電子回路装置について、図面を参照しながら説明する。なお、第１の実施の形態と同一構成部分には同様な符号（２０番増加させた番号）を付して、その説明は省略し、異なる構成部分について説明する。
【００４０】
図４は、本発明の第２の実施の形態に係る回路基板の要部を模式的に示す断面図である。回路基板には、第１の実施の形態と同様に、絶縁基板が１枚の単層基板、及び、絶縁基板と配線層が複数積層した多層基板があるが、ここでは、多層基板の場合には最上層にある１層の絶縁基板と１層の導電体層の部分を示す。また、電気部品を実装するランドとその周辺を示す。
【００４１】
まず、図４に示すように、回路基板２では、ランド３４の突出部３５上面を対向するランド側に傾斜した傾斜面４３を形成した点が、第１の実施の形態のランドとは異なり、その他の構成部分はほぼ同じ構造となっている。
【００４２】
すなわち、突出部３５の上面は、対向するランド３４から遠い部分に平坦面４１を有し、この平坦面４１に連接し、且つ対向するランド３４側に向かうに従って絶縁基板３１に近接して突出部３５の側壁に到達する傾斜面４３を有する。そしてこの傾斜面４３の突出部３５側壁と交差する位置は、導電体３２の回路配線部３３の上面４２より高く、且つ絶縁性樹脂３６の表面より５μｍ程度高くなっている。また、この傾斜面４３は曲面となっている。
【００４３】
次に、この回路基板の製造方法の１例を、図５を参照して説明する。図５は、上記構造の回路基板の製造方法を工程順に模式的に示す断面図である。ただし、第１の実施の形態と共通する工程は省略して、本実施の形態の特徴的な工程のみに絞って説明する。
【００４４】
まず、第１の実施の形態による図２（ａ）から図２（ｅ）工程を経て、図５（ａ）に示すように、突出部３５を有するランド３４と回路配線部３３からなる導電体３２を絶縁基板３１上に形成する。
【００４５】
次に、図５（ｂ）に示すように、導電体３２及び絶縁基板３１上にフォトレジストを塗布した後、露光、現像、エッチング等のフォトエッチング法により、突出部３５の傾斜面の形成予定位置に開口部を有するマスクパターン３８を形成する。すなわち、突出部３５の対向するランド３４側の上部及び側部の一部が露出するようにパターニングを行い、次に、マスクパターン３８をマスクにしてホット塩化第二鉄水溶液あるいは酸等で突出部３５の露出部分のエッチングを行う。エッチング液に曝された突出部３５上面の角部分からエッチングが進行し、突出部３５の側部側に下がった傾斜面４３が形成される。この傾斜面４３は、エッチングにより導電体３２側に凹んだ曲率に形成される。
【００４６】
次に、図５（ｃ）に示すように、マスクパターン３８を除去することにより、回路配線部３３及びこの回路配線部３３に連接して上面に突出部３５を有するランド３４とからなり、この突出部３５上面が平坦面４１と傾斜面４３を有する所定パターンの導電体３２ができあがる。
【００４７】
この後、第１の実施の形態と同様に、ランド３４及び回路配線部３３の露出部分上にニッケル等のメッキを施して、ポリイミド等からなる絶縁性樹脂３６をマスクキングによる印刷法等で形成し、図４に示すような回路基板２を作製する。
【００４８】
なお、導電体３２上の絶縁樹脂３６の層厚は、突出部３５の側面に到達する傾斜面４３の位置より５μｍ程度低くなるように調整されている。
【００４９】
図６は、回路基板に、電子部品をハンダ実装してなる電子回路装置を模式的に示す断面図である。
【００５０】
図６に示すように、回路基板２のランド３４を含む突出部３５上面に所定量のハンダ３７を塗布した後、突出部３５上面に電気部品１２１の電極部１２２を位置合わせして載置し、ハンダ３７を溶融、固化させることによって、電気部品１２１の電極部１２２とランド３４とを接合している。
【００５１】
以上のような第２の実施の形態によれば、第１の実施の形態で得られる効果の他に、特に、本実施の形態では、電気部品１２１の電極部１２２がハンダ３７に接する位置に傾斜面４３が設けられているので、電気部品１２１を溶融ハンダの溜り部分により確実に載置することができ、より大きなセルフアラインメント効果を発生させることができる。従って、電気部品１２１はランド３４上の一定位置に固定されるために、電気的特性、特に高周波特性の安定化を図ることができる。
【００５２】
（第３の実施の形態）
次に、本発明の第３の実施の形態に係る回路基板、回路基板の製造方法及び電子回路装置について、図面を参照しながら説明する。なお、第１の実施の形態と同一構成部分には同様な符号（４０番増加させた番号）を付して、その説明は省略し、異なる構成部分について説明する
図７は、本発明の第３の実施の形態に係る回路基板の要部を模式的に示す断面図である。本実施の形態では、高周波回路部分と低周波回路部分を有する電子回路装置に好適な回路基板の例である。この回路基板においても、第１の実施の形態と同様に、絶縁基板が１枚の単層基板、及び、絶縁基板と配線層が複数積層した多層基板があるが、ここでは、多層基板の場合には最上層にある１層の絶縁基板と１層の導電体層の部分を示す。また、電気部品を実装するランドとその周辺を示す。
【００５３】
まず、図７に示すように、回路基板３は、高周波回路部分における導電体５２ａの回路配線部５３ａと低周波回路部分における導電体５２ｂの回路配線部分５３ｂの層厚を異ならしめた点が、第１の実施の形態の回路基板とは異なり、その他の構成部分は第１の実施の形態とほぼ同じ構造を有する。すなわち、高周波回路部分の導電体５２ａにおける突出部５５ａを含むランド５４ａと低周波回路部分の導電体５２ｂにおける突出部５５ｂを含むランド５４ｂとの層厚は同じに形成している。しかし、高周波回路部分の導電体５２ａにおける回路配線部５３ａの層厚を小さく、且つ低周波回路部分における回路配線部５３ｂの層厚を大きくしている。
【００５４】
また、絶縁性樹脂５６は、回路基板３の上面全体にわたって平坦をなすように形成するため、必然的に低周波回路部分の導電体５２ｂ上に比べて高周波回路部分の導電体５２ａ上において層厚に形成されているが、同じ層厚に形成してもよい。
【００５５】
次に、この回路基板の製造方法の１例を、図８を参照して説明する。図８は、上記構造の回路基板の製造方法を工程順に模式的に示す断面図である。ただし、第１の実施の形態と共通する工程は省略して、本実施の形態の特徴的な工程のみに絞って説明する。
【００５６】
まず、第１の実施の形態による図２（ａ）から図２（ｅ）工程を経て、図８（ａ）に示すように、突出部５５を有するランド５４と回路配線部５３からなる導電体５２を絶縁基板５１上に形成する。
【００５７】
次に、図８（ｂ）に示すように、導電体５２を覆うように絶縁基板５１上にフォトレジストを塗布して、露光、現像、エッチング等のフォトエッチング法により、高周波回路部分の導電体５２ａにおける回路配線部５３ａの形成予定位置に開口部を有するマスクパターン５８を形成する。
【００５８】
次に、図８（ｃ）に示すように、マスクパターン５８をマスクにしてホット塩化第二鉄水溶液あるいは酸等で露出した高周波回路部分の回路配線部５３ａの表面を絶縁基板５１に平行に所定量エッチング除去し、低周波回路部分における回路配線部５３ｂの層厚に比べて小さくする。その後、マスクパターン５８を除去して、高周波回路部分の回路配線部５３ａの層厚が小さく、且つ低周波回路部分の回路配線部５３ｂの層厚が大きく形成された導電体５２ａ、５２ｂが得られる。
【００５９】
この後、第１の実施の形態と同様に、露出した突出部５５ａ、５５ｂ及びランド５４ａ、５４ｂ部分上にニッケル等のメッキを施した後、絶縁性樹脂５６を印刷法等で導電体５２ａ、５２ｂを覆うように絶縁基板５１上に形成し、突出部５５ａ、５５ｂを含むランド５４ａ、５４ｂ上に開口部を形成し、図７に示すような回路基板３を作製する。
【００６０】
なお、導電体５２ａ、５２ｂ上の絶縁樹脂５６の厚さは、突出部５５ａ、５５ｂの上面６１の位置より５μｍ程低くなるように膜厚が調整されている。
【００６１】
また、図７に示すように、突出部５５ａ、５５ｂを含むランド５４ａ、５４ｂ及び絶縁性樹脂５６は、第１の実施の形態と全く同じである。従って、回路基板３に電気部品をハンダ実装してなる電子回路装置は、回路配線部の層厚を除いて図３と同じ形態になる。
【００６２】
以上のような第３の実施の形態によれば、第１の実施の形態で得られる効果の他に、特に、本実施の形態では、導電体５２ａ、５２ｂの回路配線部５３ａ、５３ｂの高さ、すなわち層厚をランド５４ａ、５４ｂの突出部５５ａ、５５ｂの高さ、すなわちランド５４ａ、５４ｂを含む突出部５５ａ、５５ｂの層厚とは独立して調整できるために、例えば、電気部品を実装するランド５４ａ、５４ｂを含む突出部５５ａ、５５ｂの層厚を固定し、そして、低周波回路部分の回路配線部５３ｂの層厚を最適化しておいて、高周波回路部分の回路配線部５３ａの層厚を調整することによりインピーダンスの調整が簡単に行える。従って、インピーダンスの微調整のために電気部品の位置変更等を繰り返すという無駄を排除することができる。
【００６３】
以上、本発明の実施の形態を説明したが、本発明は、上記実施の形態に限定されるものではなく、本発明の要旨を逸脱しない範囲内で種々変形して実施することができる。
【００６４】
例えば、第２の実施の形態と第３の実施の形態とを組合わせてもよい。すなわち、第３の実施の形態の回路基板において、ランドの突出部上面に、第２の実施の形態における傾斜面を設けてもよい。
【００６５】
また、第３の実施の形態では、導電体の層厚で高周波回路のインピーダンスを調整しているので、調整する前の導電体の層厚を、第１または第２の実施の形態の場合より予め厚くしてもよい。
【００６６】
また、上記実施の形態では、導電体の層厚の調整及び分離溝の形成に、ウェットエッチング法を用いたが、スパッタリング法等のドライエッチングを用いても差し支えない。更に、分離溝の形成には、レーザによる蒸発を利用することもでき、この場合はエッチングマスクが不要となる。
【００６７】
【発明の効果】
本発明によれば、隣接の導電体間のショート、及び電気部品と導電体との接合不良を抑制できる回路基板、回路基板の製造方法及び電子回路装置を提供することができる。
【図面の簡単な説明】
【図１】図１（ａ）は本発明の第１の実施の形態に係る回路基板を模式的に示す断面図、図１（ｂ）はその回路基板の平面図。
【図２】本発明の第１の実施の形態に係る回路基板の製造方法を工程順に模式的に示す断面図。
【図３】本発明の第１の実施の形態に係る回路基板に、電子部品をハンダ実装してなる電子回路装置を模式的に示す断面図。
【図４】本発明の第２の実施の形態に係る回路基板を模式的に示す断面図。
【図５】本発明の第２の実施の形態に係る回路基板の製造方法を工程順に模式的に示す断面図。
【図６】本発明の第２の実施の形態に係る回路基板に、電子部品をハンダ実装してなる電子回路装置を模式的に示す断面図。
【図７】本発明の第３の実施の形態に係る回路基板を模式的に示す断面図。
【図８】本発明の第３の実施の形態に係る回路基板の製造方法を工程順に模式的に示す断面図。
【図９】図９（ａ）は従来の回路基板を模式的に示す断面図、図９（ｂ）はその回路基板の上に電子部品をハンダ実装してなる電子回路装置を模式的に示す断面図。
【符号の説明】
１、２、３、５回路基板
１１、３１、５１、１０１絶縁基板
１２、３２、５２、５２ａ、５２ｂ、１０２導電体
１２ａ銅箔
１３、３３、５３、５３ａ、５３ｂ、１０３回路配線部
１４、３４、５４、５４ａ、５４ｂ、１０４ランド
１５、３５、５５、５５ａ、５５ｂ突出部
１６、３６、５６、１０６絶縁性樹脂
１７、３７、１０７ハンダ
１８、１９、３８、５８マスクパターン
２０開口部
２５、４５、６５分離溝
２６、４６隙間
４１平坦面
４２、６１上面
４３傾斜面
１２１電気部品
１２２電極部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit board, a circuit board manufacturing method, and an electronic circuit device, and more particularly to a circuit board that functions at a high frequency, a circuit board manufacturing method, and an electronic circuit device.
[0002]
[Prior art]
In recent years, electronic devices in the information communication field and information processing field have been developed with the aim of speeding up, downsizing, and high functionality, and in particular, in the field of transmitting large amounts of information such as images, there is a high demand for speeding up. The circuit boards for electronic circuit devices used there are being processed with higher precision and multilayers.
[0003]
Currently, circuit boards have a structure in which a wiring layer made of a conductor is surrounded or embedded by an insulating member. Chip components (hereinafter simply referred to as electrical components) such as semiconductor components, resistors, and capacitors are mounted on the exposed wiring layer and are electrically connected via solder or the like. Multi-layer boards in which a plurality of thin plate-shaped insulating members and wiring layers are alternately stacked to form a multi-layer circuit on a single circuit board are also widely used. Or three-dimensionally connected to the ground.
[0004]
These circuit boards are a method of forming a circuit by sticking a copper plate to an insulating plate material depending on the material, application, etc., masking necessary wiring parts, and etching away unnecessary copper by chemical treatment etc. The wiring part is made by copper plating or the like, or the conductive paste material is printed on the insulating member in the form of wiring and then baked and made. In addition, a method of hardening the conductor wiring with an insulating resin has been proposed. In these circuit boards, the surface of the conductor is formed on the same surface without any height.
[0005]
A conventional circuit board will be described with reference to FIG. FIG. 9A is a cross-sectional view showing the main part of the circuit board, and FIG. 9B is a diagram schematically showing a state in which components are mounted on the circuit board. FIG. 9 shows the outermost surface portion in the case of a single-layer circuit board or a multilayer circuit board.
[0006]
As shown in FIG. 9A, the circuit board 5 has a conductor 102 composed of a circuit wiring portion 103 and a land 104 fixed on an insulating substrate 101, and prevents solder from flowing out and conducting on the insulating substrate 101. An insulating resin (insulating layer) 106 is formed so as to cover the conductor 102 for insulation between the bodies. An opening is formed in the insulating resin 106 on the land 104, and the land 104 is open. It is partially exposed from the part.
[0007]
Therefore, normally, in the circuit board 5, the upper surface of the land 104 is depressed by the thickness of the insulating resin 104.
[0008]
Then, as shown in FIG. 9B, after solder is formed on the upper surface of the land 104 by printing or the like, the electrode part 122 of the electrical component 121 is aligned with the land 104 of the circuit board 5. Then, by melting and solidifying the solder 107 by reflow or the like, the electrode 122 of the electrical component 121 and the land 104 are solder-connected to produce an electronic circuit device (see, for example, Patent Document 1).
[0009]
In the conventional circuit board described above, since the upper surface of the land 104 is lower by the layer thickness of the insulating resin 104, it corresponds to the layer thickness of the insulating resin 104 between the electrode portion 122 of the electrical component 121 and the land 103. Space is created. Therefore, when the electrical component 121 is solder-mounted on the land 104 of the circuit board 5, the solder connection depends on the amount of the solder 107. That is, when the solder 107 is applied in a larger amount than the layer thickness of the insulating resin 106, the amount of solder becomes excessive, generation of solder balls that do not contribute to bonding, outflow of solder, and the like occur, and between adjacent conductors 102 occur. A short circuit will occur. On the contrary, when the solder 107 is applied less than the equivalent thickness of the insulating resin 106, there is a problem that the electrode part 122 of the electrical component and the land 104 are poorly bonded. In particular, in an electrical component in which the electrode portion and the envelope are flat and have the same surface, mounting variations such as a short circuit and poor bonding occur.
[0010]
[Patent Document 1]
JP-A-8-330715 (second page, FIG. 2)
[0011]
[Problems to be solved by the invention]
As described above, according to the conventional circuit board, since the insulating resin surface is formed at a position higher than the land upper surface, when there are too many solders, adjacent conductors due to generation of solder balls or outflow of solder A short circuit occurs. On the other hand, if the amount of solder is too small, there is a problem such as defective bonding between the electrical component and the conductor.
[0012]
Accordingly, the present invention has been made in view of the above problems, and provides a circuit board, a circuit board manufacturing method, and an electronic circuit device that can suppress short circuit between adjacent conductors and poor connection between the conductor and electric components. For the purpose.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, a circuit board according to one embodiment of the present invention includes an insulating substrate, a land fixed to a main surface of the insulating substrate, and a conductor having a circuit wiring portion connected to the land, An insulating layer that at least exposes a land to cover the surface of the conductor and the insulating substrate, and a protrusion that is formed on the top surface of the land and protrudes above the surface of the insulating layer in the vicinity of the land. .
[0014]
According to another aspect of the present invention, there is provided a circuit board manufacturing method comprising: forming a conductor having a land and a circuit wiring portion connected to the land on a main surface of an insulating substrate; and at least part of the land upper surface. Forming a protruding portion on the upper surface of the land by etching away the remaining conductive material surface, exposing at least the upper surface of the protruding portion, and exposing the conductive material and the insulating substrate surface to a height of the protruding portion; And a step of covering with an insulating layer having a smaller layer thickness.
[0015]
In the electronic circuit device according to another aspect of the present invention, a conductor having a land and a circuit wiring portion connected to the land is formed on the main surface of the insulating substrate, and the upper surface of the land protrudes from the upper surface of the circuit wiring portion. A circuit board in which a protrusion is formed, at least the protrusion is exposed, and a surface of the conductor and the insulating substrate is covered with an insulating layer having a thickness smaller than a height of the protrusion; and the protrusion of the circuit board And an electrical component joined to the upper surface of the part through a joining material.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
(First embodiment)
First, a circuit board, a circuit board manufacturing method, and an electronic circuit device according to a first embodiment of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a cross-sectional view and a plan view schematically showing main parts of a circuit board according to a first embodiment of the present invention. The circuit board includes a single-layer board having a single insulating board and a multi-layer board in which a plurality of insulating boards and wiring layers are laminated. And a portion of one conductor layer. In addition, a land portion where electric parts are mounted and its periphery are shown.
[0019]
First, as shown in FIGS. 1A and 1B, the circuit board 1 is made of BT resin (bismaleimide / triazine, Mitsubishi Gas Chemical Co., Ltd.), epoxy resin, ceramic, or the like. Has a small and rigid insulating substrate 11. On the surface of the insulating substrate 11, a conductor 12 serving as a patterned wiring layer made of copper or the like is provided. The conductor 12 has a circuit wiring portion 13 for constituting a predetermined circuit function and a land 14 connected to the circuit wiring portion 13 to connect an electrical component, and is formed to a thickness of, for example, about 30 μm. Yes.
[0020]
The circuit wiring portion 13 is connected to other electrical components, the ground, etc. on the surface portion of the insulating substrate 11 in the case of a single-layer circuit board, and on the surface portion or inside in the case of a multilayer circuit board. It is connected to the circuit wiring part of the conductor.
[0021]
An insulating resin 16 as an insulating layer is formed on the insulating substrate 11 so as to cover the conductors 12, so that the conductors 12 are insulated from each other, and a bonding material such as solder is not used when mounting electrical components. It spreads easily and functions as a mask layer for preventing a short circuit between adjacent conductors 12 from occurring. The insulating resin 16 is made of a heat-resistant polyimide resin, epoxy resin, or the like, and is formed on the conductor 12 with a layer thickness of about 5 μm.
[0022]
An opening is formed in the insulating resin 16 on the land 14, and the land 14 is partially exposed from the opening. A protruding portion 15 protruding upward from the surface of the insulating resin 16 is formed on a part of the exposed surface of the land 14.
[0023]
Next, an example of this circuit board manufacturing method will be described with reference to FIG. FIG. 2 is a cross-sectional view schematically showing a method of manufacturing the circuit board having the above structure in the order of steps.
[0024]
First, as shown in FIG. 2A, a copper foil 12 a that finally becomes the conductor 12 is attached to the upper surface of the insulating substrate 11.
[0025]
Next, as shown in FIG. 2B, a photoresist is applied onto the copper foil 12a, and the photoresist is patterned by a photo-etching method such as exposure, development, and etching to form a conductor having a predetermined pattern. A mask pattern 18 having an opening 20 is provided.
[0026]
Next, as shown in FIG. 2C, using the mask pattern 18 as a mask, for example, hot ferric chloride aqueous solution is sprayed on the copper foil 12a, or the insulating substrate 11 in FIG. 2B is hot. After dipping into a ferric chloride aqueous solution and etching the copper foil 12a from the opening 20 until it reaches the insulating substrate 11, the separation groove 25 is formed. Then, the mask pattern 18 is removed, and the separation groove 25 performs insulation separation. The conductor 12 having a predetermined pattern is formed.
[0027]
Next, as shown in FIG. 2 (d), a photoresist is applied on the conductor 12, and the top surface of the land 14 is exposed by a photo-etching method such as exposure, development, and etching as in FIG. 2 (b). A mask pattern 19 is formed at a position that becomes the protruding portion 15.
[0028]
Next, as shown in FIG. 2E, using the mask pattern 19 as a mask, for example, a hot ferric chloride aqueous solution is sprayed on the conductor 12, or the insulating substrate 11 in FIG. The exposed conductor 12 is dipped in a ferric chloride aqueous solution and etched so as to be deeper than the layer thickness of the insulating resin 16 shown in FIG. Thereafter, the mask pattern 19 is removed, and the conductor 12 having the protrusion 15 having a flat upper surface is formed on the land 14.
[0029]
Thereafter, nickel or the like is plated on the exposed portions of the conductor 12 such as the land 14 including the circuit wiring portion 13 and the protruding portion 15 in order to improve the bondability and prevent corrosion.
[0030]
Then, as shown in FIG. 2F, for example, polyimide is used so as to cover the surface of the other conductor 12 except for the land 14 and to fill the separation groove 25 between the adjacent conductors 12. An insulating resin 16 made of, for example, is formed on the insulating substrate 11 by mask king printing or the like. The insulating resin 16 is formed to have a layer thickness that is about 5 μm lower than the upper surface of the protruding portion 15.
[0031]
The insulating resin 16 is formed by applying a photosensitive resin such as photosensitive polyimide over the entire surface of the insulating substrate 11 so as to cover the conductor 12, and performing a normal photo-etching method such as exposure, development, and etching. An opening may be provided on 14.
[0032]
As a result, the circuit board 1 is obtained in which the protruding portion 15 of the land 14 on which the electrical component is mounted is higher than the surface of the insulating resin 16 in the vicinity thereof by about 5 μm.
[0033]
FIG. 3 is a cross-sectional view schematically showing an electronic circuit device formed by soldering electrical components on the circuit board.
[0034]
As shown in FIG. 3, a predetermined amount of bonding material, for example, solder 17, is formed on the land 14 including the protruding portion 15 of the circuit board 1 by a printing method using a mask or the like. On the projecting portion 15 of the land 14, the electrode portion 122 and the envelope are flat and the electrode portion 122 of the electric component 121 having the same plane is aligned and placed, and the solder 17 is melted by a reflow method. Then, the electrode part 122 of the electrical component 121 is joined to the land 14 by solidifying.
[0035]
According to the circuit board 1 of the above-described embodiment, the land 14 is provided with the protruding portion 15 protruding upward from the surface of the insulating resin 16, and the electrical component 121 is mounted on the upper surface of the protruding portion 15. Accordingly, since the electric component 121 is fixed with the insulating resin 16 while maintaining a gap of about 5 μm, the electrode portion 122 of the electric component 121 and the land 14 are reliably bonded. For this reason, since the application quantity of the solder 17 which joins the electrical component 121 and the land 14 decreases, the improvement of a high frequency characteristic can be aimed at.
[0036]
Further, the gap 26 between the electrical component 121 and the insulating resin 16 provides a space for excess solder to escape, and the state where the excess solder is adhered to the land 14 can be maintained. It is possible to suppress the occurrence of defects such as a short circuit between the conductors 12. Therefore, it is possible to prevent bonding failure due to insufficient solder in a conventional circuit board, short circuit between adjacent conductors due to excessive solder, and the like.
[0037]
Furthermore, since the gap 26 is provided between the electric component 121 and the insulating resin 16, a self-alignment effect can be expected. That is, the electrical component 121 moves to return to the center portion of the protruding portion 15 in the land 14 due to the surface tension of the molten solder 17, so that the electrical component 121 is rearranged and mounted at an appropriate position. Therefore, since the electrical component 121 is fixed at a certain position based on the pattern of the circuit board 1, electrical characteristics, particularly high frequency characteristics can be stabilized.
[0038]
Furthermore, since the gap 26 is provided between the electric component 121 and the insulating resin 16, it is possible to prevent the flux used in the solder bonding process of the electric component 121 and the remaining of the cleaning agent in the cleaning process after the solder bonding. Can do. Therefore, it is possible to suppress deterioration of electrical components and conductors that occur after a long time, and it is possible to ensure long-term reliability of the electronic circuit device.
[0039]
(Second Embodiment)
Next, a circuit board, a circuit board manufacturing method, and an electronic circuit device according to a second embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol (number increased 20th) is attached | subjected to the same component as 1st Embodiment, the description is abbreviate | omitted and a different component is demonstrated.
[0040]
FIG. 4 is a cross-sectional view schematically showing the main part of the circuit board according to the second embodiment of the present invention. As in the first embodiment, the circuit board includes a single-layer board having one insulating board and a multilayer board in which a plurality of insulating boards and wiring layers are stacked. Indicates a portion of one insulating substrate and one conductor layer in the uppermost layer. Moreover, the land which mounts an electrical component and its periphery are shown.
[0041]
First, as shown in FIG. 4, the circuit board 2 is different from the land of the first embodiment in that an inclined surface 43 is formed by inclining the upper surface of the protruding portion 35 of the land 34 toward the opposite land. Other components have almost the same structure.
[0042]
That is, the upper surface of the projecting portion 35 has a flat surface 41 at a portion far from the opposing land 34, is connected to the flat surface 41, and comes closer to the insulating substrate 31 toward the opposing land 34 side. It has the inclined surface 43 which reaches | attains the side wall of 35. The position of the inclined surface 43 intersecting the side wall of the protruding portion 35 is higher than the upper surface 42 of the circuit wiring portion 33 of the conductor 32 and higher than the surface of the insulating resin 36 by about 5 μm. The inclined surface 43 is a curved surface.
[0043]
Next, an example of this circuit board manufacturing method will be described with reference to FIG. FIG. 5 is a cross-sectional view schematically showing a method of manufacturing the circuit board having the above structure in the order of steps. However, the steps common to the first embodiment are omitted, and only the characteristic steps of the present embodiment will be described.
[0044]
First, through the steps of FIG. 2A to FIG. 2E according to the first embodiment, as shown in FIG. 5A, a conductor comprising a land 34 having a protrusion 35 and a circuit wiring portion 33. 32 is formed on the insulating substrate 31.
[0045]
Next, as shown in FIG. 5B, after applying a photoresist on the conductor 32 and the insulating substrate 31, the inclined surface of the protrusion 35 is to be formed by a photoetching method such as exposure, development, and etching. A mask pattern 38 having an opening at the position is formed. That is, patterning is performed so that the upper portion of the projecting portion 35 on the opposite land 34 side and a part of the side portion are exposed, and then using the mask pattern 38 as a mask, the projecting portion is formed with hot ferric chloride aqueous solution or acid. Etching of the exposed portion of 35 is performed. Etching proceeds from the corner portion of the upper surface of the protruding portion 35 exposed to the etching solution, and an inclined surface 43 lowered to the side of the protruding portion 35 is formed. The inclined surface 43 is formed to have a curvature that is recessed toward the conductor 32 by etching.
[0046]
Next, as shown in FIG. 5C, the mask pattern 38 is removed to form a circuit wiring portion 33 and a land 34 connected to the circuit wiring portion 33 and having a protrusion 35 on the upper surface. A conductor 32 having a predetermined pattern in which the upper surface of the protrusion 35 has a flat surface 41 and an inclined surface 43 is completed.
[0047]
Thereafter, as in the first embodiment, the exposed portions of the land 34 and the circuit wiring portion 33 are plated with nickel or the like, and the insulating resin 36 made of polyimide or the like is formed by a printing method using masking or the like. Then, the circuit board 2 as shown in FIG. 4 is produced.
[0048]
The layer thickness of the insulating resin 36 on the conductor 32 is adjusted to be about 5 μm lower than the position of the inclined surface 43 that reaches the side surface of the protruding portion 35.
[0049]
FIG. 6 is a cross-sectional view schematically showing an electronic circuit device in which electronic components are solder-mounted on a circuit board.
[0050]
As shown in FIG. 6, after a predetermined amount of solder 37 is applied to the upper surface of the protruding portion 35 including the land 34 of the circuit board 2, the electrode portion 122 of the electrical component 121 is aligned and placed on the upper surface of the protruding portion 35. By melting and solidifying the solder 37, the electrode part 122 of the electrical component 121 and the land 34 are joined.
[0051]
According to the second embodiment as described above, in addition to the effects obtained in the first embodiment, particularly in the present embodiment, the electrode portion 122 of the electrical component 121 is located at a position in contact with the solder 37. Since the inclined surface 43 is provided, the electrical component 121 can be reliably placed on the molten solder reservoir, and a larger self-alignment effect can be generated. Therefore, since the electrical component 121 is fixed at a fixed position on the land 34, the electrical characteristics, particularly the high frequency characteristics can be stabilized.
[0052]
(Third embodiment)
Next, a circuit board, a circuit board manufacturing method, and an electronic circuit device according to a third embodiment of the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals (numbers increased by 40), the description thereof is omitted, and FIG. It is sectional drawing which shows typically the principal part of the circuit board which concerns on 3 embodiment. The present embodiment is an example of a circuit board suitable for an electronic circuit device having a high frequency circuit portion and a low frequency circuit portion. Also in this circuit board, as in the first embodiment, there is a single-layer board with one insulating board and a multi-layer board in which a plurality of insulating boards and wiring layers are laminated. Shows a portion of one insulating substrate and one conductor layer in the uppermost layer. Moreover, the land which mounts an electrical component and its periphery are shown.
[0053]
First, as shown in FIG. 7, the circuit board 3 is different in the layer thickness of the circuit wiring portion 53a of the conductor 52a in the high frequency circuit portion and the circuit wiring portion 53b of the conductor 52b in the low frequency circuit portion. Unlike the circuit board of the first embodiment, the other components have substantially the same structure as that of the first embodiment. That is, the land 54a including the protrusion 55a in the conductor 52a in the high frequency circuit portion and the land 54b including the protrusion 55b in the conductor 52b in the low frequency circuit portion are formed to have the same layer thickness. However, the layer thickness of the circuit wiring portion 53a in the conductor 52a in the high frequency circuit portion is reduced, and the layer thickness of the circuit wiring portion 53b in the low frequency circuit portion is increased.
[0054]
Further, since the insulating resin 56 is formed so as to be flat over the entire upper surface of the circuit board 3, the layer thickness is inevitably higher on the conductor 52a in the high-frequency circuit portion than on the conductor 52b in the low-frequency circuit portion. However, they may be formed to the same layer thickness.
[0055]
Next, an example of this circuit board manufacturing method will be described with reference to FIG. FIG. 8 is a cross-sectional view schematically showing a method of manufacturing a circuit board having the above structure in the order of steps. However, the steps common to the first embodiment are omitted, and only the characteristic steps of the present embodiment will be described.
[0056]
First, through the steps of FIG. 2A to FIG. 2E according to the first embodiment, as shown in FIG. 8A, a conductor comprising a land 54 having a protruding portion 55 and a circuit wiring portion 53. 52 is formed on the insulating substrate 51.
[0057]
Next, as shown in FIG. 8B, a photoresist is applied on the insulating substrate 51 so as to cover the conductor 52, and the conductor of the high-frequency circuit portion is subjected to a photoetching method such as exposure, development, and etching. A mask pattern 58 having an opening at a position where the circuit wiring portion 53a is to be formed in 52a is formed.
[0058]
Next, as shown in FIG. 8C, the surface of the circuit wiring portion 53a of the high-frequency circuit portion exposed with hot ferric chloride aqueous solution or acid is placed in parallel with the insulating substrate 51 using the mask pattern 58 as a mask. It is removed by quantitative etching, and is made smaller than the layer thickness of the circuit wiring portion 53b in the low frequency circuit portion. Thereafter, the mask pattern 58 is removed to obtain the conductors 52a and 52b in which the layer thickness of the circuit wiring portion 53a in the high frequency circuit portion is small and the layer thickness of the circuit wiring portion 53b in the low frequency circuit portion is large. .
[0059]
Thereafter, as in the first embodiment, after the exposed protrusions 55a and 55b and the lands 54a and 54b are plated with nickel or the like, the insulating resin 56 is printed on the conductors 52a, The circuit board 3 as shown in FIG. 7 is manufactured by forming it on the insulating substrate 51 so as to cover 52b and forming openings on the lands 54a and 54b including the protruding portions 55a and 55b.
[0060]
Note that the thickness of the insulating resin 56 on the conductors 52a and 52b is adjusted to be about 5 μm lower than the position of the upper surface 61 of the protrusions 55a and 55b.
[0061]
Further, as shown in FIG. 7, the lands 54a and 54b including the protruding portions 55a and 55b and the insulating resin 56 are exactly the same as those in the first embodiment. Therefore, an electronic circuit device in which electrical components are solder-mounted on the circuit board 3 has the same form as FIG. 3 except for the layer thickness of the circuit wiring portion.
[0062]
According to the third embodiment as described above, in addition to the effects obtained in the first embodiment, particularly in the present embodiment, the height of the circuit wiring portions 53a and 53b of the conductors 52a and 52b is increased. That is, the layer thickness can be adjusted independently of the height of the protrusions 55a and 55b of the lands 54a and 54b, that is, the layer thickness of the protrusions 55a and 55b including the lands 54a and 54b. The layer thickness of the protruding portions 55a and 55b including the lands 54a and 54b to be mounted is fixed, and the layer thickness of the circuit wiring portion 53b in the low frequency circuit portion is optimized, and the circuit wiring portion 53a in the high frequency circuit portion is optimized. The impedance can be easily adjusted by adjusting the layer thickness. Accordingly, it is possible to eliminate the waste of repeatedly changing the position of the electrical component for fine adjustment of the impedance.
[0063]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
[0064]
For example, the second embodiment and the third embodiment may be combined. That is, in the circuit board according to the third embodiment, the inclined surface in the second embodiment may be provided on the upper surface of the protruding portion of the land.
[0065]
In the third embodiment, since the impedance of the high-frequency circuit is adjusted by the layer thickness of the conductor, the layer thickness of the conductor before adjustment is more than that of the first or second embodiment. You may make it thick beforehand.
[0066]
In the above embodiment, the wet etching method is used for adjusting the layer thickness of the conductor and forming the separation groove. However, dry etching such as a sputtering method may be used. Further, evaporation by a laser can be used for forming the separation groove. In this case, an etching mask is not necessary.
[0067]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the circuit board which can suppress the short circuit between adjacent conductors, and the joining defect of an electrical component and a conductor, the manufacturing method of a circuit board, and an electronic circuit apparatus can be provided.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view schematically showing a circuit board according to a first embodiment of the present invention, and FIG. 1B is a plan view of the circuit board.
FIG. 2 is a cross-sectional view schematically showing the circuit board manufacturing method according to the first embodiment of the present invention in the order of steps.
FIG. 3 is a cross-sectional view schematically showing an electronic circuit device in which electronic components are solder-mounted on the circuit board according to the first embodiment of the present invention.
FIG. 4 is a cross-sectional view schematically showing a circuit board according to a second embodiment of the present invention.
FIG. 5 is a cross-sectional view schematically showing a circuit board manufacturing method according to the second embodiment of the present invention in the order of steps;
FIG. 6 is a cross-sectional view schematically showing an electronic circuit device in which electronic components are solder-mounted on a circuit board according to a second embodiment of the present invention.
FIG. 7 is a cross-sectional view schematically showing a circuit board according to a third embodiment of the present invention.
FIG. 8 is a cross-sectional view schematically showing a method of manufacturing a circuit board according to a third embodiment of the present invention in the order of steps.
FIG. 9A is a cross-sectional view schematically showing a conventional circuit board, and FIG. 9B schematically shows an electronic circuit device in which electronic components are solder-mounted on the circuit board. Sectional drawing.
[Explanation of symbols]
1, 2, 3, 5 Circuit board 11, 31, 51, 101 Insulating board 12, 32, 52, 52a, 52b, 102 Conductor 12a Copper foil 13, 33, 53, 53a, 53b, 103 Circuit wiring part 14, 34, 54, 54a, 54b, 104 Land 15, 35, 55, 55a, 55b Protrusion 16, 36, 56, 106 Insulating resin 17, 37, 107 Solder 18, 19, 38, 58 Mask pattern 20 Opening 25 45, 65 Separation groove 26, 46 Gap 41 Flat surface 42, 61 Upper surface 43 Inclined surface 121 Electrical component 122 Electrode portion

Claims

An insulating substrate;
A conductor having a land fixed to the main surface of the insulating substrate and a circuit wiring portion connected to the land;
An insulating layer that at least exposes the land and covers the conductor and the surface of the insulating substrate;
A protrusion formed on the top surface of the land and protruding above the surface of the insulating layer near the land;
A circuit board comprising:

The circuit board according to claim 1, wherein the protrusion has a flat upper surface as a whole.

2. The circuit board according to claim 1, wherein the protruding portion has an inclined surface whose upper surface reaches a side surface of the protruding portion, and the inclined surface is located above the surface of the insulating layer in the vicinity thereof. .

The circuit board according to claim 1, wherein the circuit wiring portions have different layer thicknesses.

Forming a conductor having a predetermined pattern having a land and a circuit wiring portion connected to the land on the main surface of the insulating substrate;
Leaving the at least part of the land upper surface and etching away the other conductor surface to form a protrusion on the land upper surface;
Covering at least the upper surface of the protruding portion and covering the conductor and the insulating substrate surface with an insulating layer having a layer thickness smaller than the height of the protruding portion;
A method of manufacturing a circuit board, comprising:

6. The method of manufacturing a circuit board according to claim 5, further comprising a step of selectively removing the upper surface of the protruding portion to form an inclined surface after the forming step of the protruding portion.

7. The circuit board according to claim 5, further comprising a step of removing the surface of the circuit wiring portion in a part of the conductor to make it different from the layer thickness of the circuit wiring portion in the other conductor. Manufacturing method.

A conductor having a land and a circuit wiring portion connected to the land is formed on the main surface of the insulating substrate, and a protruding portion protruding from the upper surface of the circuit wiring portion is formed on the top surface of the land, and at least the protruding portion is exposed. A circuit board in which the surfaces of the conductor and the insulating substrate are covered with an insulating layer having a layer thickness smaller than the height of the protruding portion;
An electrical component bonded to the upper surface of the protruding portion of the circuit board via a bonding material;
An electronic circuit device.

The circuit board according to claim 8, wherein the protrusion has a flat upper surface.

The circuit board according to claim 8, wherein the protruding portion has an inclined surface whose upper surface reaches a side surface of the protruding portion, and the inclined surface is located above the surface of the insulating layer in the vicinity thereof. .

The circuit board according to claim 8, wherein the circuit wiring portion has a different layer thickness.