JP3924453B2

JP3924453B2 - WIRING BOARD AND ELECTRONIC DEVICE USING THE SAME

Info

Publication number: JP3924453B2
Application number: JP2001365687A
Authority: JP
Inventors: 英典鹿田
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2001-11-30
Filing date: 2001-11-30
Publication date: 2007-06-06
Anticipated expiration: 2021-11-30
Also published as: JP2003168872A

Description

【０００１】
【発明の属する技術分野】
本発明は、絶縁層および配線導体が交互に複数層積層され、絶縁層を挟んで上下に位置する配線導体同士を絶縁層に設けた貫通導体により電気的に接続して成る配線基板およびこれを用いた電子装置に関する。
【０００２】
【従来の技術】
従来、半導体素子や抵抗器等の電子部品を搭載するために用いられる配線基板として、ガラス繊維基材および変性ポリフェニレンエーテル樹脂から成る絶縁層と銅箔等の金属箔から成る配線導体とを交互に複数積層して成るプリント基板が知られている。このようなプリント基板は、絶縁層表面に被着した銅箔をエッチングして配線導体を形成し、配線導体が形成された絶縁層を複数枚、積層圧着して多層化することにより製作されている。
【０００３】
しかしながらこのプリント基板は、絶縁層表面の配線導体部と非配線導体部との段差により表面が凹凸状態となることから、変性ポリフェニレンエーテル樹脂の含有量を50〜80重量％と多くして絶縁層に若干の可塑性を持たせた絶縁シートを用い、絶縁シートに配線導体を被着させる際に、絶縁シートの配線導体に当接する部位を配線導体の厚みに対応して塑性変形させることにより配線導体を絶縁シート中に埋入し、配線基板表面に凹凸が形成されないようにしている。なお、プリント基板の上下の配線導体は、絶縁層に形成された貫通導体を介して接続されている。
【０００４】
このような配線基板は、ガラス繊維基材に変性ポリフェニレンエーテル樹脂を含浸させた絶縁シートにレーザで貫通孔を形成した後、この貫通孔内に金属粉末および熱硬化性樹脂から成る導体ペーストをスクリーン印刷（圧入）で充填し貫通導体を形成し、他方、耐熱性樹脂から成る転写用シート基材の表面に銅箔を被着し、所定のパターンにエッチングして転写用シート基材に配線導体を形成し、しかる後、貫通導体が形成された絶縁シートに配線導体が形成された転写用シート基材を圧接して配線導体を絶縁シートに転写埋入するとともに貫通導体と接続させ、さらに、絶縁シートから転写用シート基材を剥離した後、配線導体が埋入された絶縁シートを複数枚積層して熱プレスを用いて変性ポリフェニレンエーテル樹脂を硬化一体化させることにより製作される。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記の配線基板は、絶縁層に含有される変性ポリフェニレンエーテル樹脂量を50〜80重量％と多くしていることから、絶縁層を積層して熱プレスする際に、熱プレスの熱によってガラス繊維基材に対して変性ポリフェニレンエーテル樹脂が大きく流動してしまい、それと同時に絶縁層表面の配線導体の変形や移動が発生し、その結果、貫通導体とそれに接続される配線導体との位置ずれが発生し、断線を生じてしまうという問題点を有していた。
【０００６】
本発明は、かかる従来技術の問題点に鑑み完成されたものであり、その目的は、積層して熱プレスする時に貫通導体とそれに接続される配線導体との位置ずれを防止することができ、接続信頼性に優れた配線基板およびこれを用いた電子装置を提供するものである。
【０００７】
【課題を解決するための手段】
本発明の配線基板は、ガラス繊維基材に変性ポリフェニレンエーテル樹脂を含浸させた絶縁層と金属箔から成る配線導体とを交互に複数層積層するとともに、絶縁層を挟んで上下に位置する配線導体同士を絶縁層に設けた貫通孔を導体で充填して成る貫通導体により電気的に接続して成る配線基板において、絶縁層は変性ポリフェニレンエーテル樹脂の含有量が40〜45重量％であり、貫通導体は、金属粉末とトリアジン系熱硬化性樹脂とから成るとともに、半径500μｍ以内の範囲に４〜12個分布するように配設されていることを特徴とするものである。
【０００８】
また、本発明の電子装置は、上記の配線基板の表面に電子部品を実装するとともに、この電子部品の電極を配線導体または貫通導体に電気的に接続して成ることを特徴とするものである。
【０００９】
本発明の配線基板によれば、絶縁層の変性ポリフェニレンエーテル樹脂の含有量を40〜45％と少なくしたことから、絶縁層を積層して熱プレスする際に、熱プレスの熱によってガラス繊維基材に対して変性ポリフェニレンエーテル樹脂が大きく流動することはなく、また、貫通導体を半径500μｍ以内の範囲に４〜12個分布するように配設したことから、貫通導体のアンカー効果により変性ポリフェニレンエーテル樹脂の流動をより抑制することができ、その結果、絶縁層表面の配線導体の変形や移動が発生したり、貫通導体とそれに接続される配線導体との位置ずれが発生することはなく、貫通導体と配線導体との断線等のない接続信頼性に優れた配線基板とすることができる。
【００１０】
また、本発明の電子装置によれば、上記の配線基板の表面に電子部品を実装するとともに、この電子部品の電極を配線導体または貫通導体に電気的に接続したことから、貫通導体とそれに接続される配線導体とが確実に接合でき、その結果、貫通導体と配線導体との断線等のない接続信頼性に優れた電子装置とすることができる。
【００１１】
【発明の実施の形態】
次に、本発明の配線基板およびこれを用いた電子装置を添付の図面に基づいて詳細に説明する。図１は、本発明の配線基板に半導体素子等の電子部品を搭載して成る電子装置の実施の形態の一例を示す断面図であり、図２は、本発明の配線基板の絶縁層に形成された貫通導体の分布状態の一例を示す平面図である。これらの図において、１は絶縁層、２は配線導体、３は貫通孔、４は貫通導体であり、主にこれらで本発明の配線基板５が構成される。また、６は電子部品であり、主に配線基板５と電子部品６と本発明の電子装置が構成される。
【００１２】
絶縁層１は、その厚みが50〜150μｍであり、配線導体２を支持するとともに上下に位置する配線導体２間の絶縁を保持する機能を有し、ガラス繊維基材に変性ポリフェニレンエーテル樹脂を含浸させて成る。なお、絶縁層１の厚みが50μｍ未満であると配線基板５の剛性が低下して、配線基板５が撓んで反りが発生し易くなる傾向があり、150μｍを超えると配線基板５の厚みが不要に厚いものとなり軽量化が困難となる傾向がある。従って、絶縁層１の厚みは50〜150μｍが好ましい。
【００１３】
そして、本発明においては、絶縁層１中の変性ポリフェニレンエーテル樹脂の含有量を40〜45重量％とすることが重要である。絶縁層１の変性ポリフェニレンエーテル樹脂の含有量を40〜45％と少なくすることにより、絶縁層１を積層して熱プレスする際に、熱プレスの熱によってガラス繊維基材に対して変性ポリフェニレンエーテル樹脂が大きく流動することはなく、後述する絶縁層１表面の配線導体２の変形や移動および貫通導体４とそれに接続される配線導体２との位置ずれを抑制して、貫通導体４と配線導体２との接続信頼性を高めることができる。変性ポリフェニレンエーテル樹脂の含有量が40重量％より少ないと、ガラス繊維基材に変性ポリフェニレンエーテル樹脂が充分に含浸されず絶縁層１に空隙が生じ、電子部品６を実装する際のリフロー等の急激な熱履歴で絶縁層１に膨れや剥がれが生じてしまう傾向にあり、他方、45重量％を超えると絶縁層１を積層して熱プレスする時に変性ポリフェニレンエーテル樹脂が流動して絶縁層１表面の配線導体２が変形してしまい、貫通導体４とそれに接続される配線導体２との位置ずれが発生し、断線を生じてしまい易くなる傾向にある。従って、絶縁層１中の変性ポリフェニレンエーテル樹脂の含有率を40〜45重量％とすることが重要である。なお、変性ポリフェニレンエーテル樹脂の架橋密度をあげるために、トリアリルイソシアヌレート等の架橋剤を添加しても良い。
【００１４】
また、各絶縁層１の表面には配線導体２が被着・埋入されている。配線導体２は、配線基板４に搭載される半導体素子等の電子部品６の各電極を外部電気回路基板（図示せず）に電気的に接続する導電路の一部としての機能を有し、幅が20〜200μｍ、厚みが５〜50μｍで、銅やアルミニウム・ニッケル・銀・金等の金属箔から成り、特に加工性および安価という観点からは銅箔から成ることが好ましい。配線導体２の幅が20μｍ未満となると配線導体２の変形や断線が発生しやすくなる傾向があり、200μｍを超えると高密度配線が形成できなくなる傾向がある。また、配線導体２の厚みが５μｍ未満になると配線導体２の強度が低下し変形や断線が発生しやすくなる傾向があり、50μｍを超えると絶縁層１への埋入が困難となる傾向がある。したがって、配線導体２は、その幅を20〜200μｍ、厚みを５〜50μｍとすることが好ましい。
【００１５】
また、各絶縁層１には、その上面から下面にかけて貫通導体４が複数個配設されている。これらの貫通導体４は、絶縁層１の上下に位置する配線導体２間を電気的に接続する機能を有し、その直径が30〜100μｍであり、絶縁層１に設けた貫通孔３に銅や銀・錫合金等の金属粉末とトリアジン系熱硬化性樹脂とから成る導体を埋め込むことにより形成されている。なお、貫通孔３の直径が30μｍ未満になるとその加工が困難となる傾向があり、100μｍを超えると高密度配線が形成できなくなる傾向がある。したがって、貫通孔３、その直径を30〜100μｍとすることが好ましい。
【００１６】
なお、上述したように絶縁層１中の変性ポリフェニレンエーテル樹脂の含有量を40〜45重量％と少なくしたことから、絶縁層１を積層して熱プレスする際に変性ポリフェニレンエーテル樹脂がガラス繊維基材に効率良く含浸・圧縮されて硬化されるので、絶縁層１中に形成される貫通導体４の金属粉末同士も強固に接続でき、その結果、長期の熱履歴を加えても、接続信頼性に優れる貫通導体４とすることができる。
【００１７】
このような貫通導体４は、半径500μｍ以内の範囲に４〜12個分布するように配設することが重要である。貫通導体４を半径500μｍ以内の範囲に４〜12個分布するように配設することにより、貫通導体４のアンカー効果により変性ポリフェニレンエーテル樹脂の流動をより抑制することができ、その結果、絶縁層１表面の配線導体２の変形や移動が発生したり、貫通導体４とそれに接続される配線導体２との位置ずれが発生することはなく、貫通導体４と配線導体２との断線等のない接続信頼性に優れた配線基板５とすることができる。なお、貫通導体４がその各々から半径500μｍ以内の範囲に４個より少ないと貫通導体４のアンカー効果が低下し、絶縁層１を積層して熱プレスする際に絶縁層１表面の配線導体２が変形してしまい、貫通導体４とそれに接続される配線導体２との位置ずれが発生し、断線を生じてしまい易くなる傾向にある。従って、貫通導体４は、半径500μｍ以内の範囲に４〜12個分布するように配設することが重要である。
【００１８】
このような配線基板５は、以下に述べる方法により製作される。まず、ガラス繊維基材に変性ポリフェニレンエーテル樹脂をその含有量が40〜45重量％になるように含浸させて乾燥することにより絶縁シートを製作する。次に、絶縁シートの所定の位置に炭酸ガスレーザやＹＡＧレーザ等の従来周知の方法を採用して直径が30〜100μｍの貫通孔３を穿設する。この時、貫通孔３は、半径500μｍ以内の範囲に４〜12個分布するように配設する。そして、貫通孔３に従来周知のスクリーン印刷法を採用して、例えば錫や銅等の金属粉およびトリアジン系樹脂等の熱硬化性樹脂を含む導体ペーストをスクリーン印刷法（圧入）で充填することによって貫通導体４を形成する。その後、別途準備した、表面に銅箔から成る配線導体２を所定のパターンに被着形成した、ポリエチレンテレフタレート（ＰＥＴ）樹脂等の耐熱性樹脂からなる転写シートを絶縁シートに、所定の貫通導体４と配線導体２とが接続するように位置合わせして重ね合わせ、これらを熱プレス機を用いて100〜150℃の温度で数分間プレスすることにより転写シートを絶縁シートに圧接して、配線導体２を絶縁シートに転写埋入させる。しかる後、転写シートを絶縁シートから剥離するとともに配線導体２を埋入した絶縁シートを複数枚上下に重ね合わせ、熱プレス機を用いて150〜200℃の温度で数時間加熱プレスすることにより、配線基板５が製造される。
【００１９】
かくして、本発明の配線基板５によれば、絶縁層１の熱変性ポリフェニレンエーテル樹脂の含有量を40〜45％と少なくしたことから、絶縁層１を積層して熱プレスする際に変性ポリフェニレンエーテル樹脂の流動を抑制でき、絶縁層１表面の配線導体２の変形を防止でき、また、貫通導体４とそれに接続される配線導体２との位置ずれが発生し、貫通導体４をその各々から半径500μｍ以内の範囲に４〜12個の貫通導体４を分布するように配設したことから、貫通導体４のアンカー効果により、貫通導体４とそれに接続される配線導体２とが確実に接合でき、その結果、貫通導体４と配線導体２との断線等のない接続信頼性に優れた配線基板とすることができる。
【００２０】
さらに、絶縁層１の一方の最外層表面に形成された配線導体２の一部は、電子部品６の各電極に導体バンプ11を介して接合される電子部品６接続用の実装用電極２ａを形成し、また、絶縁層１の他方の最外層表面に形成された配線導体２の一部は、外部電気回路基板（図示せず）の各電極に導体バンプ11を介して接続される外部接続用の実装用電極２ｂを形成している。
【００２１】
実装用電極２ａ・２ｂの表面には、その酸化腐蝕を防止するとともに導体バンプ11との接続を良好とするために、半田等の導体バンプ11との濡れ性が良好で耐腐蝕性に優れたニッケル−金等のめっき層が被着されている。
【００２２】
また、最外層の絶縁層１および実装用電極２ａ・２ｂには、その中央部を露出させる開口を有する耐半田樹脂層12が被着されている。耐半田樹脂層12は、その厚みが10〜50μｍであり、例えばアクリル変性エポキシ樹脂等の感光性樹脂と光開始剤等とから成る混合物に30〜70重量％のシリカやタルク等の無機粉末フィラーを含有させた絶縁材料から成り、隣接する実装用電極２ａ・２ｂ同士が導体バンプ11により電気的に短絡することを防止するとともに、実装用電極２ａ・２ｂと絶縁層１との接合強度を向上させる機能を有する。
【００２３】
このような耐半田樹脂層12は、感光性樹脂と光開始剤と無機粉末フィラーとから成る未硬化樹脂フィルムを最外層の絶縁層１表面に被着させる、あるいは、熱硬化性樹脂と無機粉末フィラーとから成る未硬化樹脂ワニスを最外層の絶縁層１表面に塗布するとともに乾燥し、しかる後、露光・現像により開口部を形成し、これをＵＶ硬化および熱硬化させることにより形成される。
【００２４】
かくして、本発明の電子装置によれば、配線基板５の表面に電子部品６を実装するとともに、この電子部品６の電極を配線導体２または貫通導体４に電気的に接続したことから、貫通導体４とそれに接続される配線導体２とが確実に接合でき、その結果、貫通導体４と配線導体２との断線等のない接続信頼性に優れた電子装置とすることができる。
【００２５】
なお、本発明は上述の実施例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であれば種々の変更は可能であり、例えば上述の実施例では絶縁層１を４層積層した場合を例示したが、５層以上であってもかまわない。
【００２６】
【発明の効果】
本発明の配線基板によれば、絶縁層の変性ポリフェニレンエーテル樹脂の含有量を40〜45％と少なくしたことから、絶縁層を積層して熱プレスする際に、熱プレスの熱によってガラス繊維基材に対して変性ポリフェニレンエーテル樹脂が大きく流動することはなく、また、貫通導体を半径500μｍ以内の範囲に４〜12個分布するように配設したことから、貫通導体のアンカー効果により変性ポリフェニレンエーテル樹脂の流動をより抑制することができ、その結果、絶縁層表面の配線導体の変形や移動が発生したり、貫通導体とそれに接続される配線導体との位置ずれが発生することはなく、貫通導体と配線導体との断線等のない接続信頼性に優れた配線基板とすることができる。
【００２７】
また、本発明の電子装置によれば、上記の配線基板の表面に電子部品を実装するとともに、この電子部品の電極を配線導体または貫通導体に電気的に接続したことから、貫通導体とそれに接続される配線導体とが確実に接合でき、その結果、貫通導体と配線導体との断線等のない接続信頼性に優れた電子装置とすることができる。
【００２８】
【図面の簡単な説明】
【図１】本発明の配線基板に半導体素子等の電子部品を搭載して成る電子装置の実施の形態の一例を示す断面図である。
【図２】本発明の配線基板の絶縁層に形成された貫通導体の分布状態の一例を示す平面図である。
【符号の説明】
１・・・・・・絶縁層
２・・・・・・配線導体
３・・・・・・貫通孔
４・・・・・・貫通導体
５・・・・・・配線基板
６・・・・・・電子部品[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wiring board in which a plurality of insulating layers and wiring conductors are alternately stacked, and wiring conductors that are positioned above and below the insulating layer are electrically connected by a through conductor provided in the insulating layer. The present invention relates to the electronic device used.
[0002]
[Prior art]
Conventionally, as a wiring board used for mounting electronic components such as semiconductor elements and resistors, insulating layers made of glass fiber base material and modified polyphenylene ether resin and wiring conductors made of metal foil such as copper foil are alternately used. A printed circuit board formed by laminating a plurality of layers is known. Such a printed circuit board is manufactured by etching a copper foil deposited on the surface of an insulating layer to form a wiring conductor, and laminating and crimping a plurality of insulating layers on which the wiring conductor is formed. Yes.
[0003]
However, this printed circuit board has an uneven surface due to the level difference between the wiring conductor portion and the non-wiring conductor portion on the surface of the insulating layer, so the content of the modified polyphenylene ether resin is increased to 50 to 80% by weight. When a wiring conductor is attached to the insulating sheet, the portion of the insulating sheet that contacts the wiring conductor is plastically deformed in accordance with the thickness of the wiring conductor. Is embedded in an insulating sheet so that irregularities are not formed on the surface of the wiring board. Note that the upper and lower wiring conductors of the printed circuit board are connected via through conductors formed in the insulating layer.
[0004]
In such a wiring board, a through hole is formed by a laser in an insulating sheet in which a glass fiber base material is impregnated with a modified polyphenylene ether resin, and then a conductive paste made of metal powder and a thermosetting resin is screened in the through hole. Filled by printing (press-fit) to form a through conductor, and on the other hand, a copper foil is deposited on the surface of a transfer sheet substrate made of a heat-resistant resin, etched into a predetermined pattern, and a wiring conductor on the transfer sheet substrate Thereafter, the transfer sheet base material on which the wiring conductor is formed is pressed against the insulating sheet on which the through conductor is formed, and the wiring conductor is transferred and embedded in the insulating sheet and connected to the through conductor, After peeling off the transfer sheet base material from the insulating sheet, a plurality of insulating sheets with embedded wiring conductors are laminated and the modified polyphenylene ether resin is cured and integrated using a hot press. It is produced by Rukoto.
[0005]
[Problems to be solved by the invention]
However, since the amount of the modified polyphenylene ether resin contained in the insulating layer is as high as 50 to 80% by weight in the above wiring board, when the insulating layer is stacked and hot pressed, The modified polyphenylene ether resin flows greatly with respect to the glass fiber substrate, and at the same time, deformation and movement of the wiring conductor on the surface of the insulating layer occur, resulting in misalignment between the through conductor and the wiring conductor connected thereto. Has occurred, resulting in a disconnection.
[0006]
The present invention has been completed in view of the problems of the prior art, and its purpose is to prevent misalignment between the through conductor and the wiring conductor connected thereto when being laminated and hot-pressed, A wiring board having excellent connection reliability and an electronic device using the wiring board are provided.
[0007]
[Means for Solving the Problems]
The wiring board according to the present invention comprises a plurality of insulating layers in which a glass fiber base material is impregnated with a modified polyphenylene ether resin and a wiring conductor made of a metal foil, and a plurality of wiring conductors, and a wiring conductor positioned above and below the insulating layer. In a wiring board formed by electrically connecting through-holes formed by filling conductors with through-holes provided in insulating layers, the insulating layer has a modified polyphenylene ether resin content of 40 to 45% by weight, and penetrates The conductor is made of a metal powder and a triazine-based thermosetting resin, and is arranged so that 4 to 12 conductors are distributed within a radius of 500 μm or less.
[0008]
An electronic device according to the present invention is characterized in that an electronic component is mounted on the surface of the wiring board and the electrodes of the electronic component are electrically connected to a wiring conductor or a through conductor. .
[0009]
According to the wiring board of the present invention, since the content of the modified polyphenylene ether resin in the insulating layer is reduced to 40 to 45%, when the insulating layer is laminated and hot pressed, the glass fiber base is heated by the heat of the hot press. Since the modified polyphenylene ether resin does not flow greatly with respect to the material, and 4 to 12 through conductors are distributed within a radius of 500 μm, the modified polyphenylene ether is formed by the anchor effect of the through conductors. The flow of the resin can be further suppressed. As a result, the wiring conductor on the surface of the insulating layer is not deformed or moved, and the through conductor and the wiring conductor connected to the through conductor are not displaced. It can be set as the wiring board excellent in connection reliability without the disconnection etc. of a conductor and a wiring conductor.
[0010]
In addition, according to the electronic device of the present invention, the electronic component is mounted on the surface of the wiring board and the electrode of the electronic component is electrically connected to the wiring conductor or the through conductor. As a result, it is possible to obtain an electronic device having excellent connection reliability without disconnection between the through conductor and the wiring conductor.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, a wiring board of the present invention and an electronic device using the same will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic device in which electronic components such as semiconductor elements are mounted on a wiring board of the present invention, and FIG. 2 is formed on an insulating layer of the wiring board of the present invention. It is a top view which shows an example of the distribution state of the made through conductor. In these drawings, 1 is an insulating layer, 2 is a wiring conductor, 3 is a through-hole, and 4 is a through-conductor, and these mainly constitute the wiring board 5 of the present invention. Reference numeral 6 denotes an electronic component, which mainly includes the wiring board 5, the electronic component 6, and the electronic device of the present invention.
[0012]
The insulating layer 1 has a thickness of 50 to 150 μm, has a function of supporting the wiring conductor 2 and maintaining insulation between the wiring conductors 2 positioned above and below, and impregnating the glass fiber base material with a modified polyphenylene ether resin. Let me. Note that if the thickness of the insulating layer 1 is less than 50 μm, the rigidity of the wiring board 5 is lowered, and the wiring board 5 tends to bend and bend easily, and if it exceeds 150 μm, the thickness of the wiring board 5 is unnecessary. Tend to be thick and difficult to reduce weight. Therefore, the thickness of the insulating layer 1 is preferably 50 to 150 μm.
[0013]
In the present invention, it is important that the content of the modified polyphenylene ether resin in the insulating layer 1 is 40 to 45% by weight. By reducing the content of the modified polyphenylene ether resin in the insulating layer 1 to 40 to 45%, when the insulating layer 1 is laminated and hot pressed, the modified polyphenylene ether is applied to the glass fiber substrate by the heat of the hot press. The resin does not flow largely, and the deformation and movement of the wiring conductor 2 on the surface of the insulating layer 1 to be described later and the displacement between the through conductor 4 and the wiring conductor 2 connected thereto are suppressed, and the through conductor 4 and the wiring conductor Connection reliability with 2 can be improved. If the content of the modified polyphenylene ether resin is less than 40% by weight, the glass fiber base material is not sufficiently impregnated with the modified polyphenylene ether resin, resulting in voids in the insulating layer 1 and abrupt reflow or the like when mounting the electronic component 6. The insulating layer 1 tends to swell or peel off due to a slight heat history. On the other hand, when it exceeds 45% by weight, the modified polyphenylene ether resin flows when the insulating layer 1 is laminated and hot pressed, and the surface of the insulating layer 1 The wiring conductor 2 is deformed, the positional deviation between the through conductor 4 and the wiring conductor 2 connected to the through conductor 4 is likely to occur, and the wire breakage tends to occur. Therefore, it is important that the content of the modified polyphenylene ether resin in the insulating layer 1 is 40 to 45% by weight. In order to increase the crosslinking density of the modified polyphenylene ether resin, a crosslinking agent such as triallyl isocyanurate may be added.
[0014]
A wiring conductor 2 is deposited and embedded on the surface of each insulating layer 1. The wiring conductor 2 has a function as a part of a conductive path for electrically connecting each electrode of an electronic component 6 such as a semiconductor element mounted on the wiring board 4 to an external electric circuit board (not shown). It has a width of 20 to 200 μm and a thickness of 5 to 50 μm, and is made of a metal foil such as copper, aluminum, nickel, silver, or gold. In particular, from the viewpoint of workability and low cost, it is preferably made of a copper foil. If the width of the wiring conductor 2 is less than 20 μm, the wiring conductor 2 tends to be easily deformed or disconnected, and if it exceeds 200 μm, high-density wiring tends to be unable to be formed. Further, if the thickness of the wiring conductor 2 is less than 5 μm, the strength of the wiring conductor 2 tends to be reduced and deformation or disconnection tends to occur, and if it exceeds 50 μm, embedding in the insulating layer 1 tends to be difficult. . Therefore, the wiring conductor 2 preferably has a width of 20 to 200 μm and a thickness of 5 to 50 μm.
[0015]
Each insulating layer 1 is provided with a plurality of through conductors 4 from the upper surface to the lower surface. These through conductors 4 have a function of electrically connecting the wiring conductors 2 positioned above and below the insulating layer 1, have a diameter of 30 to 100 μm, and have copper holes in the through holes 3 provided in the insulating layer 1. It is formed by embedding a conductor made of a metal powder such as silver or tin alloy and a triazine-based thermosetting resin. If the diameter of the through hole 3 is less than 30 μm, the processing tends to be difficult, and if it exceeds 100 μm, high-density wiring tends to be unable to be formed. Therefore, it is preferable that the through hole 3 has a diameter of 30 to 100 μm.
[0016]
As described above, since the content of the modified polyphenylene ether resin in the insulating layer 1 is reduced to 40 to 45% by weight, when the insulating layer 1 is laminated and hot-pressed, the modified polyphenylene ether resin becomes a glass fiber group. Since the material is efficiently impregnated, compressed and cured, the metal powder of the through conductor 4 formed in the insulating layer 1 can be firmly connected. As a result, even if a long thermal history is added, the connection reliability It can be set as the through-conductor 4 excellent in.
[0017]
It is important that 4 to 12 such penetrating conductors 4 are arranged in a radius of 500 μm or less. By disposing 4 to 12 through conductors 4 within a radius of 500 μm, the anchoring effect of the through conductors 4 can further suppress the flow of the modified polyphenylene ether resin. There is no deformation or movement of the wiring conductor 2 on one surface, or no displacement between the through conductor 4 and the wiring conductor 2 connected thereto, and there is no disconnection between the through conductor 4 and the wiring conductor 2. It can be set as the wiring board 5 excellent in connection reliability. If the number of through conductors 4 is less than 4 within a radius of 500 μm from each of them, the anchor effect of the through conductors 4 is lowered, and the wiring conductor 2 on the surface of the insulating layer 1 is laminated when the insulating layer 1 is laminated and hot pressed. Is deformed, and a positional shift between the through conductor 4 and the wiring conductor 2 connected to the through conductor 4 tends to occur, and the wire breakage tends to occur. Therefore, it is important to arrange 4 to 12 through conductors 4 within a radius of 500 μm.
[0018]
Such a wiring board 5 is manufactured by the method described below. First, an insulating sheet is produced by impregnating a glass fiber substrate with a modified polyphenylene ether resin so that the content thereof is 40 to 45% by weight and drying. Next, a through hole 3 having a diameter of 30 to 100 μm is formed at a predetermined position of the insulating sheet by using a conventionally known method such as a carbon dioxide laser or a YAG laser. At this time, the through holes 3 are arranged so that 4 to 12 through holes are distributed within a radius of 500 μm. Then, a conventionally well-known screen printing method is adopted for the through-hole 3, and for example, a conductive paste containing a metal powder such as tin or copper and a thermosetting resin such as a triazine resin is filled by the screen printing method (press-fit). The through conductor 4 is formed by the above. After that, a separately prepared transfer sheet made of a heat-resistant resin such as polyethylene terephthalate (PET) resin having a wiring conductor 2 made of copper foil formed in a predetermined pattern on the surface is used as an insulating sheet, and a predetermined through conductor 4 is formed. And the wiring conductor 2 are aligned and overlapped so that they are connected, and these are pressed at a temperature of 100 to 150 ° C. for several minutes using a hot press machine, so that the transfer sheet is pressed against the insulating sheet, and the wiring conductor 2 is transferred and embedded in an insulating sheet. Thereafter, the transfer sheet is peeled off from the insulating sheet and the insulating sheets embedded with the wiring conductors 2 are stacked one above the other, and heated and pressed at a temperature of 150 to 200 ° C. for several hours using a hot press machine. The wiring board 5 is manufactured.
[0019]
Thus, according to the wiring board 5 of the present invention, since the content of the heat-modified polyphenylene ether resin in the insulating layer 1 is reduced to 40 to 45%, the modified polyphenylene ether is formed when the insulating layer 1 is laminated and hot-pressed. The flow of the resin can be suppressed, the deformation of the wiring conductor 2 on the surface of the insulating layer 1 can be prevented, and the positional deviation between the through conductor 4 and the wiring conductor 2 connected to the through conductor 4 occurs. Since 4 to 12 through conductors 4 are distributed in a range of 500 μm or less, the through conductor 4 and the wiring conductor 2 connected thereto can be reliably joined by the anchor effect of the through conductor 4, As a result, it is possible to obtain a wiring board having excellent connection reliability without disconnection between the through conductor 4 and the wiring conductor 2.
[0020]
Further, a part of the wiring conductor 2 formed on the surface of one outermost layer of the insulating layer 1 has a mounting electrode 2 a for connecting the electronic component 6 bonded to each electrode of the electronic component 6 through the conductor bump 11. A part of the wiring conductor 2 formed on the surface of the other outermost layer of the insulating layer 1 is connected to each electrode of an external electric circuit board (not shown) via a conductor bump 11. The mounting electrode 2b is formed.
[0021]
The surface of the mounting electrodes 2a and 2b has good wettability with the conductor bumps 11 such as solder and excellent corrosion resistance in order to prevent the oxidative corrosion and to make the connection with the conductor bumps 11 good. A plating layer such as nickel-gold is applied.
[0022]
The outermost insulating layer 1 and the mounting electrodes 2a and 2b are covered with a solder-resistant resin layer 12 having an opening that exposes the central portion thereof. The solder-resistant resin layer 12 has a thickness of 10 to 50 μm. For example, 30 to 70% by weight of an inorganic powder filler such as silica or talc in a mixture of a photosensitive resin such as an acrylic-modified epoxy resin and a photoinitiator. It is made of an insulating material containing Nb and prevents the adjacent mounting electrodes 2a and 2b from being electrically short-circuited by the conductor bump 11, and improves the bonding strength between the mounting electrodes 2a and 2b and the insulating layer 1. It has a function to make it.
[0023]
Such a solder-resistant resin layer 12 is formed by depositing an uncured resin film composed of a photosensitive resin, a photoinitiator, and an inorganic powder filler on the surface of the outermost insulating layer 1, or a thermosetting resin and an inorganic powder. An uncured resin varnish composed of a filler is applied to the surface of the outermost insulating layer 1 and dried. Thereafter, an opening is formed by exposure and development, and this is formed by UV curing and heat curing.
[0024]
Thus, according to the electronic device of the present invention, the electronic component 6 is mounted on the surface of the wiring board 5 and the electrodes of the electronic component 6 are electrically connected to the wiring conductor 2 or the through conductor 4. 4 and the wiring conductor 2 connected thereto can be reliably joined. As a result, an electronic device excellent in connection reliability without disconnection between the through conductor 4 and the wiring conductor 2 can be obtained.
[0025]
Note that the present invention is not limited to the above-described embodiment, and various modifications are possible within a range not departing from the gist of the present invention. For example, in the above-described embodiment, four insulating layers 1 are laminated. Although the case was illustrated, it may be five layers or more.
[0026]
【The invention's effect】
According to the wiring board of the present invention, since the content of the modified polyphenylene ether resin in the insulating layer is reduced to 40 to 45%, when the insulating layer is laminated and hot pressed, the glass fiber base is heated by the heat of the hot press. Since the modified polyphenylene ether resin does not flow greatly with respect to the material, and 4 to 12 through conductors are distributed within a radius of 500 μm, the modified polyphenylene ether is formed by the anchor effect of the through conductors. The flow of the resin can be further suppressed. As a result, the wiring conductor on the surface of the insulating layer is not deformed or moved, and the through conductor and the wiring conductor connected to the through conductor are not displaced. It can be set as the wiring board excellent in connection reliability without the disconnection etc. of a conductor and a wiring conductor.
[0027]
In addition, according to the electronic device of the present invention, the electronic component is mounted on the surface of the wiring board and the electrode of the electronic component is electrically connected to the wiring conductor or the through conductor. As a result, it is possible to obtain an electronic device having excellent connection reliability without disconnection between the through conductor and the wiring conductor.
[0028]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of an electronic device in which electronic components such as semiconductor elements are mounted on a wiring board of the present invention.
FIG. 2 is a plan view showing an example of a distribution state of through conductors formed in an insulating layer of a wiring board according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulation layer 2 ... Wiring conductor 3 ... Through-hole 4 ... Through-conductor 5 ... Wiring board 6 ... ..Electronic parts

Claims

A plurality of insulating layers in which a glass fiber base material is impregnated with a modified polyphenylene ether resin and a wiring conductor made of a metal foil are alternately laminated, and the wiring conductors positioned above and below the insulating layer are arranged between the insulating layers. In the wiring board formed by electrically connecting through holes provided in a conductor with a through conductor, the insulating layer has a content of the modified polyphenylene ether resin of 40 to 45% by weight, and the through conductor Comprises a metal powder and a triazine-based thermosetting resin, and is arranged so as to be distributed in a range of 4 to 12 within a radius of 500 μm.

An electronic device comprising: an electronic component mounted on a surface of the wiring board according to claim 1; and an electrode of the electronic component electrically connected to the wiring conductor or the through conductor.