JP3754217B2 - Method for manufacturing printed wiring board - Google Patents

Description

【００４１】
上記表１から判るように、樹脂エッチング工程を省いて製造した比較形態のプリント配線板では、検査した試料３００ヶすべてにリーク不良が発生した。これに対し、本実施形態のプリント配線板では、検査した試料３００ヶすべてが良好であった。
本実施形態のプリント配線板では、樹脂エッチング工程により、クイックエッチングが不完全なために、下地樹脂絶縁層２３上に残った不要な無電解メッキ層２４や、粗化工程の際に配線層２７から剥がれて付着した銅微粒子２７Ｂを除去しているので、比較形態のプリント配線板のようにリーク不良が発生しない。
【００４２】
以上のように、本実施形態の製造方法によれば、配線層２７を形成する際、クイックエッチングが不十分で、配線層２７，２７間の下地樹脂絶縁層２３上に、不要な無電解メッキ層２４が完全に除去されずに残渣が残った場合でも、その後、樹脂エッチング工程によって、これを除去することができる。
さらに、エッチング粗化工程において、配線層２７の表面２７Ａが粗化される際に、その一部が粒状のまま配線層２７，２７間に露出する下地樹脂絶縁層２３の表面２３Ａに付着した場合でも、樹脂エッチング工程によって、この銅微粒子２７Ｂを除去することができる。
従って、配線層２７，２７間でリーク不良が発生することのない、信頼性の高いプリント配線板を製造することができる。
【００４３】
（実施形態２）
次いで、第２の実施の形態について、図９及び図１０を参照しつつ説明する。本実施形態の製造方法では、フルアディティブ法により配線層４７を形成する点が上記実施形態１と異なる。従って、上記実施形態１と同様な部分の説明は省略または簡略化する。
まず、上記参考形態と同様の被積層基板４２を用意し、下地絶縁層粗化工程において、被積層基板４２の下地樹脂絶縁層４３の表面４３Ａを粗化しておく。
【００４４】
次に、下地樹脂絶縁層４３の表面４３Ａにドライフィルムを貼り付け、所定のパターンを用いて露光・現像し、図９（ａ）に示すように、配線層を形成しない部分にレジスト膜４５を形成する。
次に、レジスト膜４５から露出した下地樹脂絶縁層４３の表面４３Ａに、無電解銅メッキを厚付けし、図９（ｂ）に示すように、厚さ２０μｍの無電解メッキ層４４を形成する。
無電解メッキ層４４を形成後、強アルカリ（ＮａＯＨ水溶液）で、レジスト膜４５を剥離して、図９（ｃ）に示すように、配線層４７，４７を形成する。
【００４５】
次に、エッチング粗化工程において、蟻酸を含む粗化液で７０秒間処理して、図１０（ａ）に示すように、配線層４７の表面４７Ａを粗化する。上記のように、蟻酸を含む粗化液を用いることで、配線層４７の表面４７Ａを起伏の激しい良好な粗化状態にすることができる。また、上記実施形態１と同様に、このエッチング粗化工程で、配線層４７から銅微粒子４７Ｂが剥がれ落ちて、配線層４７，４７間の下地樹脂絶縁層４３に付着する場合がある。
【００４６】
次に、樹脂エッチング工程において、過マンガン酸ナトリウムを含む樹脂エッチング液で８０℃、１分間処理し、図１０（ｂ）に示すように、配線層４７，４７間に露出した下地樹脂絶縁層４３の表層部分を、深さ４μｍ樹脂エッチングする。この樹脂エッチングにより、エッチング粗化工程の際に、配線層４７から剥がれて下地樹脂絶縁層４３上に付着した銅微粒子４７Ｂを除去することができる。
【００４７】
また、樹脂エッチングする深さを１μｍ以上の４μｍとしたので、上記参考形態及び実施形態１と同様に、リーク不良の原因となる付着した銅微粒子を確実に除去することができる。また、７μｍ以下の４μｍだけ樹脂エッチングしたので、下地樹脂絶縁層４３が大きく抉り取られたり、下地樹脂絶縁層４３の表面粗度が著しく低下することがなく、下地樹脂絶縁層４３と配線層４７との密着強度、及び下地樹脂絶縁層４３と後に積層する樹脂絶縁層との密着強度を高く維持することができる。
さらに、過マンガン酸カリウムを含む樹脂エッチング液を用いているので、下地絶縁層４３の表面４３Ａを適度に樹脂エッチングすることができ、その調整が容易である。
【００４８】
次に、配線層４７及び下地樹脂絶縁層４３上に、下地樹脂絶縁層４３と同材質の絶縁層フィルムを貼り付け、図１０（ｃ）に示すように、樹脂絶縁層４８を形成する。
その後は、上記の工程を繰り返して、配線層と樹脂絶縁層とを交互に所望の数だけ積層して、プリント配線板を完成させる。
【００４９】
以上のように、本実施形態の製造方法によれば、エッチング粗化工程において、配線層４７の表面４７Ａがエッチング粗化される際に、その一部が粒状のまま配線層４７，４７間に露出する下地樹脂絶縁層４３の表面４３Ａに付着した場合でも、樹脂エッチング工程によって、この銅微粒子４７Ｂを除去することができる。従って、配線層４７，４７間でリーク不良が発生することのない、信頼性の高いプリント配線板を製造することができる。
【００５０】
（実施形態３）
次いで、第３の実施の形態について、図１１及び図１２を参照しつつ説明する。本実施形態の製造方法では、サブトラクティブ法により配線層６７を形成する点が上記実施形態１，２と異なる。従って、上記実施形態１，２と同様な部分の説明は省略または簡略化する。
まず、上記参考形態と同様の被積層基板６２を用意し、上記参考形態及び実施形態１，２と同様に、下地絶縁層粗化工程において、被積層基板６２の下地樹脂絶縁層６３の表面６３Ａを粗化しておく。
【００５１】
次に、図１１（ａ）に示すように、無電解銅メッキを全面に施し、厚さ０．７μｍの無電解メッキ層６４を形成する。無電解メッキ層６４の表面６４Ａには、上記参考形態及び実施形態１と同様に、下地樹脂絶縁層６３の表面６３Ａと同程度の凹凸が形成される。続いて、無電解メッキ層６４の表面６４Ａ全面に、電解銅メッキを施し、厚さ２０μｍの電解メッキ層６６を形成する。
【００５２】
次に、電解メッキ層６６の表面６６Ａにドライフィルムを貼り付け、所定のパターンを用いて露光・現像し、図１１（ｂ）に示すように、配線層に対応する部分にエッチングレジスト膜６５を形成する。
その後、図１１（ｃ）に示すように、エッチングレジスト膜６５から露出した電解メッキ層６６及び無電解メッキ層６４を、エッチングにより除去する。
エッチング後は、エッチングレジスト膜６５を剥離して、図１１（ｄ）に示すように、配線層６７，６７を形成する。
【００５３】
次に、エッチング粗化工程において、図１２（ａ）に示すように、蟻酸を含む粗化液で７０秒間処理して、配線層６７の表面６７Ａを粗化する。本実施形態においても、蟻酸を含む粗化液を用いることで、配線層６７の表面６７Ａを起伏の激しい良好な粗化状態にすることができる。また、このエッチング粗化工程で、配線層６７から銅微粒子６７Ｂが剥がれ落ちて、配線層６７，６７間の下地樹脂絶縁層６３上に付着する場合がある。
【００５４】
次に、樹脂エッチング工程において、過マンガン酸カリウムを含む樹脂エッチング液で８０℃、１分間樹脂エッチングし、図１２（ｂ）に示すように、配線層６７，６７間に露出した下地樹脂絶縁層６３の表層部分を、深さ４μｍ樹脂エッチングする。この樹脂エッチングにより、エッチング粗化工程の際、配線層６７から剥がれて下地樹脂絶縁層６３上に付着した銅微粒子６７Ｂを除去することができる。
【００５５】
また、本実施形態においても、樹脂エッチングする深さが１μｍ以上の４μｍであるので、リーク不良の原因となる銅微粒子６７Ｂを確実に除去することができる。一方、７μｍ以下の４μｍだけ樹脂エッチングするので、下地樹脂絶縁層６３が大きく抉り取られたり、下地樹脂絶縁層６３の表面粗度が著しく低下することがなく、下地樹脂絶縁層６３と配線層６７との密着強度、及び下地樹脂絶縁層６３と後に積層する樹脂絶縁層との密着強度を高く維持することができる。
さらに、過マンガン酸カリウムを含む樹脂エッチング液を用いているので、下地絶縁層６３の表面６３Ａを適度に樹脂エッチングすることができ、その調整が容易である。
【００５６】
次に、配線層６７及び下地樹脂絶縁層６３上に、下地樹脂絶縁層６３と同材質の絶縁層フィルムを貼り付け、図１２（ｃ）に示すように、樹脂絶縁層６８を形成する。
その後は、上記の工程を繰り返して、配線層と樹脂絶縁層とを交互に所望の数だけ積層して、プリント配線板を完成させる。
【００５７】
以上のように、本実施形態の製造方法によれば、エッチング粗化工程において、配線層６７の表面６７Ａがエッチング粗化される際に、その一部が粒状のまま配線層６７，６７間に露出する下地樹脂絶縁層６３の表面６３Ａに付着した場合でも、樹脂エッチング工程によって、この銅微粒子６７Ｂを除去することができる。従って、配線層６７，６７間でリーク不良が発生することのない、信頼性の高いプリント配線板を製造することができる。
【００５８】
以上において、本発明を各実施形態に即して説明したが、本発明は上記実施形態に限定されるものではなく、その要旨を逸脱しない範囲で、適宜変更して適用できることはいうまでもない。
例えば、上記各実施形態では、コア基板の両面に樹脂絶縁層と配線層とを備えるプリント配線板の製造方法を示したが、コア基板なしで、絶縁層と配線層とを交互に複数層積層したプリント配線板を製造する場合にも、同様に適用することができる。
【図面の簡単な説明】
【図１】 参考形態に係り、被積層基板の断面図を示す。
【図２】 参考形態に係るプリント配線板の製造方法を示す図であり、（ａ）は被積層基板の下地樹脂絶縁層の部分拡大断面図を示し、（ｂ）は下地樹脂絶縁層の表面を粗化した状態を示す。
【図３】 参考形態に係るプリント配線板の製造方法を示す図であり、（ａ）は無電解メッキ層を形成した状態を示し、（ｂ）はレジスト膜を形成した状態を示し、（ｃ）は電解銅メッキ層を形成した状態を示す。
【図４】 参考形態に係るプリント配線板の製造方法を示す図であり、（ａ）は配線層を形成した状態を示し、（ｂ）は配線層間の下地樹脂絶縁層の表層部分を樹脂エッチングした状態を示し、（ｃ）は配線層の表面を粗化した状態を示す。
【図５】 参考形態に係るプリント配線板の製造方法を示す図であり、（ａ）は樹脂絶縁層を積層した状態を示し、（ｂ）は樹脂絶縁層の表面を粗化した状態を示す。
【図６】 参考形態に係り、プリント配線板の断面図を示す。
【図７】 実施形態１に係るプリント配線板の製造方法を示す図であり、（ａ）は下地樹脂絶縁層上に無電解メッキ層を形成した状態を示し、（ｂ）はレジスト膜を形成した状態を示し、（ｃ）は電解銅メッキ層を形成した状態を示し、（ｄ）は配線層を形成した状態を示す。
【図８】 実施形態１に係るプリント配線板の製造方法を示す図であり、（ａ）は配線層の表面をエッチング粗化した状態を示し、（ｂ）は配線層間の下地樹脂絶縁層の表層部分を樹脂エッチングした状態を示し、（ｃ）は樹脂絶縁層を積層した状態を示す。
【図９】 実施形態２に係るプリント配線板の製造方法を示す図であり、（ａ）は下地樹脂絶縁層上にレジスト膜を形成した状態を示し、（ｂ）は無電解銅メッキ層を形成した状態を示し、（ｃ）は配線層を形成した状態を示す。
【図１０】 実施形態２に係るプリント配線板の製造方法を示す図であり、（ａ）は配線層の表面をエッチング粗化した状態を示し、（ｂ）は配線層間の下地樹脂絶縁層の表層部分を樹脂エッチングした状態を示し、（ｃ）は樹脂絶縁層を積層した状態を示す。
【図１１】 実施形態３に係るプリント配線板の製造方法を示す図であり、（ａ）は下地樹脂絶縁層上に無電解メッキ層及び電解メッキ層を形成した状態を示し、（ｂ）は、エッチングレジスト膜を形成した状態を示し、（ｃ）は不要なメッキ層をエッチングして除去した状態を示し、（ｄ）は配線層を形成した状態を示す。
【図１２】 実施形態３に係るプリント配線板の製造方法を示す図であり、（ａ）は配線層の表面をエッチング粗化した状態を示し、（ｂ）は配線層間の下地樹脂絶縁層の表層部分を樹脂エッチングした状態を示し、（ｃ）は樹脂絶縁層を積層した状態を示す。
【図１３】 従来技術に係るプリント配線板の製造方法を示す図であり、（ａ）は下地樹脂絶縁層上に無電解メッキ層を形成した状態を示し、（ｂ）はレジスト膜を形成した状態を示し、（ｃ）は電解メッキ層を形成した状態を示す。
【図１４】 従来技術に係るプリント配線板の製造方法を示す図であり、（ａ）は配線層を形成した状態を示し、（ｂ）は配線層の表面を粗化した状態を示し、（ｃ）は樹脂絶縁層を積層した状態を示す。
【符号の説明】
１ プリント配線板
２，２２，４２，６２ 被積層基板
３，２３，４３，６３ 下地樹脂絶縁層
３Ａ，２３Ａ，４３Ａ，６３Ａ （下地樹脂絶縁層の）表面
４，２４，４４，６４ 無電解メッキ層
６，２６，６６ 電解メッキ層
７，２７，４７，６７ 配線層
７Ａ，２７Ａ，４７Ａ，６７Ａ （配線層の）表面
８，２８，４８，６８ 樹脂絶縁層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a printed wiring board having a base resin insulating layer, a wiring layer, and a resin insulating layer, and more particularly, to a method for manufacturing a printed wiring board capable of reliably forming a wiring layer that is unlikely to cause a leak failure. .
[0002]
[Prior art]
Conventionally, a printed wiring board having a plurality of resin insulating layers and a wiring layer formed between the layers is known. In manufacturing such a printed wiring board, the wiring layer is formed by a method such as a semi-additive method, a full additive method, or a subtractive method.
[0003]
Among them, in the semi-additive method, as shown in FIG. 13A, first, a thin electroless copper plating is performed on the base resin insulating layer 103 of the laminated substrate 102 to form an electroless plating layer 104. Next, as shown in FIG. 13B, a resist film 105 is formed in a portion where the wiring layer is not formed by a printing method, a photographic method, or the like. Next, as shown in FIG. 13C, the electrolytic plating layer 106 is formed by thickening the electrolytic copper plating on the electroless plating layer 104 exposed from the resist film 105. After this electrolytic plating process, the resist film 105 is peeled and removed, and the unnecessary electroless plating layer 104 is removed by etching, so-called quick etching, as shown in FIG. The
[0004]
After the formation of the wiring layer 107, a resin insulating layer may be laminated thereon, but in order to improve the adhesion between the wiring layer 107 and the resin insulating layer formed thereon, FIG. As shown in FIG. 14, the surface of the wiring layer 107 is roughened in advance, and then a resin insulating layer 108 is laminated as shown in FIG. As the roughening method, a method of oxidizing and roughening the surface of the wiring layer 107 with a mixed solution of sodium chlorite, sodium hydroxide, trisodium phosphate, etc. (blackening treatment), a wiring layer with formic acid, etc. For example, the surface of 107 may be etched and roughened.
[0005]
[Problems to be solved by the invention]
However, when the wiring layer 107 is formed by this semi-additive method, the unnecessary electroless plating layer 104 is not sufficiently removed by the quick etching, and is unnecessary on the base resin insulating layer 103 between the wiring layers 107 and 107. The electroless plating layer 104 remains, and a leak failure may occur between the wiring layers 107 and 107.
Further, when the wiring layer 107 or the like is roughened by etching with formic acid or the like, the copper fine particles peeled off from the wiring layer 107 may adhere to the base resin insulating layer 103 between the wiring layers 107 and 107. Leak failure sometimes occurred.
[0006]
Even when a wiring layer is formed by a full additive method or a subtractive method, when the surface of the wiring layer is roughened by etching with formic acid or the like, copper fine particles may adhere between the wiring layers. In some cases, a leak failure occurred between the layers.
[0007]
The present invention has been made in view of the present situation, and an object of the present invention is to provide a method for manufacturing a printed wiring board in which leakage defects are unlikely to occur between wiring layers.
[0008]
[Means, actions and effects for solving the problems]
The solution is a method for manufacturing a printed wiring board having a base resin insulating layer, a wiring layer formed thereon by a semi-additive method, and a resin insulating layer disposed thereon, A method for manufacturing a printed wiring board, comprising: a resin etching step of etching a surface of the base resin insulating layer exposed between the wiring layers after forming the wiring layer and before laminating the resin insulating layer.
[0009]
According to the present invention, after the wiring layer is formed by the semi-additive method, the surface of the base resin insulating layer exposed between the wiring layers is subjected to resin etching before the resin insulating layer is laminated. For this reason, when the wiring layer is formed, the quick etching is insufficient, and even if an unnecessary electroless plating layer is not completely removed and a residue remains, it is exposed between the wiring layers by the above resin etching process. By removing the surface layer portion of the underlying resin insulation layer, the residue of the electroless plating layer can be removed together. Therefore, it is possible to manufacture a highly reliable printed wiring board that does not cause a leak failure between wiring layers.
[0010]
Here, the base resin insulation layer and the resin insulation layer may be appropriately selected in consideration of the adhesion to the wiring layer, the thermal expansion coefficient, and the like. For example, epoxy resin, polyimide resin, BT resin, PPE resin, etc. Resins, composite materials of these resins and organic fibers such as glass fibers (glass woven fabrics and glass nonwoven fabrics) and polyamide fibers, or epoxy resins on three-dimensional network fluorine-based resin base materials such as continuous porous PTFE And a resin-resin composite material impregnated with the above resin.
[0011]
Further, the printed wiring board only needs to have a base resin insulating layer, a wiring layer, and a resin insulating layer. For example, the insulating layer and the wiring layer are provided on one or both sides of the core substrate or without the core substrate. And the like in which a plurality of layers are alternately laminated. Further, on the main surface of the printed wiring board, an integrated circuit chip may be mounted or a connection pad for connecting to another substrate, a pin as an input / output terminal, or the like may be provided.
[0012]
Here, it is preferable to apply the present invention when the surface of the base resin insulating layer is roughened before the wiring layer is formed. In order to improve the adhesion between the base resin insulation layer, the wiring layer, and the resin insulation layer, the base resin insulation layer is roughened in advance. In this case, the electroless plating is rough when forming the wiring layer. Since it is formed so as to enter the depth of the unevenness of the surface of the underlying resin insulation layer, the unnecessary electroless plating layer is hardly completely removed by quick etching, and a leak failure is likely to occur between the wiring layers. For this reason, in order to remove the residue of an unnecessary electroless-plating layer, the effect by performing said resin etching process is especially large.
[0013]
Further, in the printed wiring board manufacturing method, a depth of performing the resin etching on the surface of the base resin insulating layer in the resin etching step is 1 μm or more and 7 μm or less. A manufacturing method is preferable.
[0014]
According to the present invention, since the surface of the base resin insulation layer is etched by 1 μm or more, the surface layer portion of the base resin insulation layer exposed between the wiring layers is removed, and an unnecessary electroless plating layer remaining thereon is also formed. It can be removed reliably.
On the other hand, since the depth of the resin etching of the base resin insulating layer is 7 μm or less, the portion of the base resin insulating layer where the wiring layer is disposed is not greatly scraped away by the resin etching, and the base resin insulating layer The adhesion strength with the wiring layer can be maintained high, and the occurrence of delamination can be suppressed. Even if the surface of the base resin insulation layer is roughened before the wiring layer is formed, the roughness of the base resin insulation layer does not significantly decrease after the resin etching. The adhesion strength due to the anchor effect with the layer can be sufficiently increased.
[0015]
Furthermore, in the printed wiring board manufacturing method, the resin etching step includes etching the base resin insulating layer with a resin etching solution containing at least one of potassium permanganate and sodium permanganate. It is good to use the manufacturing method of the characteristic printed wiring board.
[0016]
According to the present invention, since the resin etching is performed with the resin etching solution containing at least one of potassium permanganate and sodium permanganate, the resin surface can be appropriately resin-etched. Further, the depth of the resin etching of the surface of the base resin insulating layer can be easily adjusted by appropriately changing the composition of the resin etching solution and the reaction conditions.
[0017]
Another solution is a method of manufacturing a printed wiring board having a base resin insulating layer, a wiring layer disposed thereon, and a resin insulating layer disposed thereon, An etching roughening step of etching and roughening the surface of the wiring layer after the formation of the layer; and the underlying resin insulating layer exposed between the wiring layers after the etching roughening step and before lamination of the resin insulating layer And a resin etching process for etching the surface of the printed wiring board.
[0018]
According to the present invention, since the surface of the wiring layer is roughened by the etching roughening step, the anchor effect between the wiring layer and the resin insulating layer can be improved, and the adhesion strength between them can be increased. On the other hand, when the wiring layer is roughened by etching, a part of the wiring layer may adhere to the surface of the underlying resin insulation layer exposed between the wiring layers, and such residual particles may cause leakage defects. Become. However, since the present invention includes a resin etching step, such particles can also be removed by this step. For this reason, a highly reliable printed wiring board is produced in which the adhesion reliability between the wiring layer and the resin insulating layer is increased, but the attached metal particles remain and no leak failure occurs between the wiring layers. Can do.
[0019]
Further, in the printed wiring board manufacturing method, a depth of performing the resin etching on the surface of the base resin insulating layer in the resin etching step is 1 μm or more and 7 μm or less. A manufacturing method is preferable.
[0020]
According to the present invention, since the surface of the base resin insulation layer is etched by 1 μm or more, the surface layer portion of the base resin insulation layer exposed between the wiring layers is removed and the metal adhered between the wiring layers during the etching roughening process Particles can be reliably removed.
In addition, since the surface of the base resin insulation layer is etched by 7 μm or less, the portion of the base resin insulation layer where the wiring layer is disposed is not greatly scraped away by the resin etching, and the base resin insulation layer and the wiring layer It is possible to keep the adhesion strength of the film high and suppress the occurrence of delamination. Even if the surface of the base resin insulation layer is roughened before the wiring layer is formed, the roughness of the base resin insulation layer does not significantly decrease after the resin etching. The adhesion strength due to the anchor effect with the layer can be sufficiently increased.
[0021]
Furthermore, in the method for manufacturing a printed wiring board, the etching roughening step includes roughening by etching a surface of the wiring layer with a roughening solution containing formic acid. It would be better to do it.
[0022]
According to the present invention, since the roughening solution containing formic acid is used, the surface of the wiring layer can be brought into a good roughened state with undulations. In addition, in the resin etching step, the fine particles that are peeled off from the surface of the wiring layer during the etching roughening step and are attached to the surface layer portion of the underlying resin insulating layer exposed between the wiring layers can be reliably removed. Accordingly, it is possible to more reliably prevent the occurrence of a leak failure between the wiring layers.
[0023]
Furthermore, in the printed wiring board manufacturing method, the resin etching step includes etching the base resin insulating layer with a resin etching solution containing at least one of potassium permanganate and sodium permanganate. It is good to use the manufacturing method of the characteristic printed wiring board.
[0024]
According to the present invention, since the resin etching is performed with the resin etching solution containing at least one of potassium permanganate and sodium permanganate, the resin surface can be appropriately resin-etched. Further, the depth of the resin etching of the surface of the base resin insulating layer can be easily adjusted by appropriately changing the composition of the resin etching solution and the reaction conditions.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
( Reference form )
Less than, Reference form Will be described with reference to the drawings.
This reference form In the method for manufacturing a printed wiring board according to FIG. 1, as shown in FIGS. 1 to 6, the printed wiring board 1 is manufactured by forming a wiring layer 7 by a semi-additive method.
First, a laminated substrate 2 shown in FIG. 1 is prepared in advance. This laminated substrate 2 has resin insulating layers 3 and 14 each made of epoxy resin (Provicoat manufactured by Nippon Paint Co., Ltd., trade name) on the front and back surfaces (upper and lower surfaces in the figure) of a substantially plate-like core substrate 11 made of glass epoxy. Are stacked and a wiring layer 12 is formed therebetween. Further, a plurality of blind holes 13 are formed in these resin insulating layers 3 and 14 in order to form blind via conductors. FIG. 2A shows a partially enlarged cross-sectional view of the resin insulating layer 3 (underlying resin insulating layer 3) formed on the upper side of the laminated substrate 2 in the drawing.
[0026]
Next, as shown in FIG. 2B, in the base insulating layer roughening step, the surface 3A of the base resin insulating layer 3 is roughened by a known method. If the surface 3A of the base resin insulating layer 3 is roughened in advance as described above, an anchor effect with a wiring layer or a resin insulating layer disposed thereon is improved later, and the adhesion strength is increased.
Next, electroless copper plating is performed to form an electroless plating layer 4 having a thickness of 0.7 μm as shown in FIG. Since the thickness of the electroless plating layer 4 is sufficiently smaller than the roughness of the surface 3A of the base resin insulation layer 3 (Rz value is about 3 μm), even the surface 4A of the electroless plating layer 4 has a base resin insulation layer. 3 is approximately as uneven as the surface 3A.
Next, a dry film is pasted on the surface 4A of the electroless plating layer 4, and exposure and development are performed using a predetermined pattern. As shown in FIG. 3B, a resist film 5 is formed on a portion where no wiring layer is formed. Form.
[0027]
Next, electrolytic copper plating is performed to form an electrolytic plating layer 6 having a thickness of 20 μm on the surface 4A of the electroless plating layer 4 exposed from the resist film 5 as shown in FIG.
After the electrolytic plating layer 6 is formed, the resist film 5 is peeled off with a strong alkali (NaOH aqueous solution). Then Na ₂ S ₂ O ₈ A system etching solution is sprayed onto the exposed electroless plating layer 4 and the electrolytic plating layer 6 to perform quick etching for 90 seconds to remove the unnecessary electroless plating layer 4 as shown in FIG. Then, the wiring layers 7 are formed. At this time, the unnecessary electroless plating layer 4 may not be completely removed, and the residue 4B may remain on the underlying resin insulation layer 3 between the wiring layers 7 and 7.
[0028]
Next, in the resin etching step, resin etching is performed with a resin etchant containing potassium permanganate at 80 ° C. for 1 minute, and the base resin exposed between the wiring layers 7 and 7 as shown in FIG. The surface layer portion of the insulating layer 3 is etched by a resin having a depth of 4 μm. By this resin etching, since the quick etching is incomplete, the unnecessary residue 4B of the electroless plating layer 4 remaining on the base resin insulating layer 3 can be removed.
[0029]
Further, in the above, since the depth of the resin etching is set to 4 μm that is 1 μm or more, the unnecessary residue 4B of the electroless plating layer 4 that causes a leak failure can be reliably removed. Furthermore, since the resin etching is performed by 4 μm of 7 μm or less, the base resin insulating layer 3 is not greatly scraped off, so that the adhesion strength between the base resin insulating layer 3 and the wiring layer 7 can be maintained high, Since the surface roughness of the base resin insulation layer 3 between the wiring layers 7 and 7 is not significantly reduced, the adhesion strength between the base resin insulation layer 3 and the resin insulation layer to be laminated later can be maintained high.
Furthermore, since the resin etching liquid containing potassium permanganate is used, the surface 3A of the base insulating layer 3 can be appropriately resin-etched, and adjustment thereof is easy.
[0030]
Next, in the roughening step, blackening is performed with a mixed solution of sodium chlorite, sodium hydroxide, and trisodium phosphate, and the surface 7A of the wiring layer 7 is oxidized and roughened as shown in FIG. Turn into. By this roughening step (blackening treatment), the adhesion strength between the wiring layer 7 and a resin insulating layer to be laminated thereon can be increased.
Next, an insulating layer film made of an epoxy resin of the same material as that of the base resin insulating layer 3 is attached on the wiring layer 7 and the base resin insulating layer 3, and cured, as shown in FIG. An insulating layer 8 is formed. If necessary, the pasted film (resin insulating layer 8) is exposed and developed using a predetermined pattern to form blind via conductors or the like in the resin insulating layer 8 (not shown). ) Can also be formed.
[0031]
Next, the base insulating layer roughening step is performed again, and the surface 8A of the newly laminated resin insulating layer 8 is roughened as shown in FIG.
Thereafter, the above-described steps are repeated to form a wiring layer 9 as shown in FIG. 6, and a solder resist layer 10 and the like are further formed thereon to complete the printed wiring board 1. In addition, although description is abbreviate | omitted, it forms as mentioned above also about the wiring layers 15 and 17 shown in the figure lower side among the printed wiring boards 1, the resin insulation layer 16, and the soldering resist layer 18. FIG.
[0032]
As above This reference form According to this manufacturing method, when the wiring layer 7 is formed, the quick etching is insufficient, and the unnecessary residue 4B of the electroless plating layer 4 is completely formed on the base resin insulating layer 3 between the wiring layers 7 and 7. Even if it remains without being removed, it can be removed by a resin etching step thereafter. Therefore, it is possible to manufacture a highly reliable printed wiring board 1 that does not cause a leak failure between the wiring layers 7 and 7.
[0033]
( Embodiment 1 )
Then First The embodiment will be described with reference to FIGS. 7 and 8. FIG. In the manufacturing method of this embodiment, the surface 27 of the wiring layer 27 is roughened by etching, and then the resin etching is performed. Reference form And different. the above Reference form The description of the same part as in FIG.
First, the above Reference form The same substrate 22 to be laminated as above is prepared in advance, and in the base insulating layer roughening step, the surface 23A of the base resin insulating layer 23 of the layered substrate 22 is roughened.
[0034]
Next, the above Reference form Similarly to FIG. 7A, an electroless plating layer 24 having a thickness of 0.7 μm is formed as shown in FIG. 7A. Then, as shown in FIG. 7B, the surface 24A of the electroless plating layer 24 is formed. Of these, a resist film 25 is formed in a portion where the wiring layer is not formed.
Thereafter, as shown in FIG. 7C, an electrolytic plating layer 26 having a thickness of 20 μm is formed on the surface 24A of the electroless plating layer 24 exposed from the resist film 25. After the electrolytic plating layer 26 is formed, the resist film 25 is peeled off, quick etching is performed, and unnecessary electroless plating layer 24 is removed to form wiring layers 27 and 27 as shown in FIG. When the wiring layer 27 is formed in this way, Reference form Similarly to the above, the electroless plating layer 24 may not be completely removed, and a residue (not shown) may remain between the wiring layers 27 and 27.
[0035]
Next, in the etching roughening step, the surface 27A of the wiring layer 27 is roughened by treating with a roughening solution containing formic acid for 70 seconds, as shown in FIG. By this etching roughening step, the adhesion strength between the wiring layer 27 and a resin insulating layer to be laminated thereon can be increased. Further, by using a roughening solution containing formic acid, the surface 27A of the wiring layer 27 can be brought into a good roughened state with undulations. However, in this etching roughening step, the copper fine particles 27 </ b> B may be peeled off from the wiring layer 27 and may adhere to the underlying resin insulating layer 23 between the wiring layers 27 and 27.
[0036]
After the etching roughening step, in the resin etching step, the resin etching is performed for 1 minute at 80 ° C. with a resin etching solution containing potassium permanganate, and exposed between the wiring layers 27 and 27 as shown in FIG. The surface layer portion of the underlying resin insulation layer 23 is etched by a resin having a depth of 4 μm. By this resin etching, since the quick etching is incomplete, the unnecessary electroless plating layer 24 remaining on the base resin insulating layer can be removed. At the same time, the copper fine particles 27B peeled off and adhered from the wiring layer 27 during the etching roughening step can also be removed.
[0037]
Further, since the depth of the resin etching is set to 4 μm, which is 1 μm or more, unnecessary residues of the electroless plating layer 24 and the attached copper fine particles 27B that cause leakage defects can be surely removed. Further, since the resin etching is performed by 4 μm of 7 μm or less, the base resin insulating layer 23 is not greatly scraped off, and the adhesion strength between the base resin insulating layer 23 and the wiring layer 27 can be maintained high. Further, since the surface roughness of the base resin insulation layer 23 between the wiring layers 27 and 27 is not significantly reduced, the adhesion strength between the base resin insulation layer 23 and the resin insulation layer to be laminated later can be maintained high. .
Further, since the resin etching solution containing potassium permanganate is used, the surface 23A of the base insulating layer 23 can be appropriately etched with resin, and the adjustment thereof is easy.
[0038]
Next, an insulating layer film is affixed on the wiring layer 27 and the base resin insulating layer 23 and cured to form a resin insulating layer 28 as shown in FIG.
Thereafter, the above process is repeated, and a desired number of wiring layers and resin insulating layers are alternately laminated to complete a printed wiring board.
[0039]
The occurrence of leakage defects in the printed wiring board was investigated as follows.
About the printed wiring board manufactured with the manufacturing method which concerns on this embodiment, the presence or absence of the leak defect was test | inspected about 300 samples. Specifically, the determination was made by measuring the insulation resistance with an R meter (resistance meter). Moreover, only the resin etching process was omitted as a comparative form, and the printed wiring board manufactured by the same manufacturing method as that of the present embodiment was also inspected in the same manner.
The measurement results are summarized in Table 1.
[0040]
[Table 1]

[0041]
As can be seen from Table 1 above, in the printed wiring board of the comparative form manufactured by omitting the resin etching process, leak failure occurred in all 300 samples inspected. On the other hand, in the printed wiring board of this embodiment, all 300 samples examined were good.
In the printed wiring board of the present embodiment, since the quick etching is incomplete due to the resin etching process, the unnecessary electroless plating layer 24 remaining on the base resin insulating layer 23 and the wiring layer 27 in the roughening process are used. Since the copper fine particles 27B peeled off and adhered are removed, a leak defect does not occur unlike the printed wiring board of the comparative form.
[0042]
As described above, according to the manufacturing method of this embodiment, when the wiring layer 27 is formed, quick etching is insufficient, and unnecessary electroless plating is applied on the base resin insulating layer 23 between the wiring layers 27 and 27. Even if the layer 24 is not completely removed and a residue remains, it can be removed by a resin etching process thereafter.
Further, in the etching roughening step, when the surface 27A of the wiring layer 27 is roughened, a part of the surface 27A remains adhered to the surface 23A of the base resin insulating layer 23 exposed between the wiring layers 27, 27. However, the copper fine particles 27B can be removed by the resin etching process.
Accordingly, it is possible to manufacture a highly reliable printed wiring board in which no leak failure occurs between the wiring layers 27 and 27.
[0043]
( Embodiment 2 )
Then Second The embodiment will be described with reference to FIGS. 9 and 10. FIG. In the manufacturing method of the present embodiment, the wiring layer 47 is formed by the full additive method. Embodiment 1 And different. Therefore, the above Embodiment 1 The description of the same part as in FIG.
First, the above Reference form The same substrate 42 to be laminated as above is prepared, and in the base insulating layer roughening step, the surface 43A of the base resin insulating layer 43 of the layered substrate 42 is roughened.
[0044]
Next, a dry film is attached to the surface 43A of the base resin insulation layer 43, and exposure and development are performed using a predetermined pattern. As shown in FIG. 9A, a resist film 45 is formed on a portion where no wiring layer is formed. Form.
Next, electroless copper plating is thickened on the surface 43A of the base resin insulating layer 43 exposed from the resist film 45 to form an electroless plating layer 44 having a thickness of 20 μm as shown in FIG. 9B. .
After forming the electroless plating layer 44, the resist film 45 is peeled off with strong alkali (NaOH aqueous solution) to form wiring layers 47 and 47 as shown in FIG. 9C.
[0045]
Next, in the etching roughening step, the surface 47A of the wiring layer 47 is roughened as shown in FIG. 10A by treating with a roughening solution containing formic acid for 70 seconds. As described above, by using a roughening solution containing formic acid, the surface 47A of the wiring layer 47 can be brought into a good roughened state with severe undulations. Also, above Embodiment 1 Similarly to this, in this etching roughening step, the copper fine particles 47B may peel off from the wiring layer 47 and adhere to the underlying resin insulating layer 43 between the wiring layers 47 and 47.
[0046]
Next, in the resin etching step, the base resin insulating layer 43 exposed between the wiring layers 47 and 47 is treated with a resin etching solution containing sodium permanganate at 80 ° C. for 1 minute, as shown in FIG. The surface layer portion of this is etched by resin having a depth of 4 μm. By this resin etching, it is possible to remove the copper fine particles 47B peeled off from the wiring layer 47 and adhered on the base resin insulating layer 43 during the etching roughening step.
[0047]
Moreover, since the depth of the resin etching is set to 4 μm of 1 μm or more, the above Reference form and Embodiment 1 In the same manner as described above, the adhered copper fine particles that cause leakage defects can be reliably removed. Further, since the resin etching is performed by 4 μm of 7 μm or less, the base resin insulating layer 43 is not greatly scraped off, and the surface roughness of the base resin insulating layer 43 is not significantly reduced, and the base resin insulating layer 43 and the wiring layer 47 are not degraded. And the adhesion strength between the underlying resin insulation layer 43 and the resin insulation layer laminated later can be maintained high.
Furthermore, since the resin etching solution containing potassium permanganate is used, the surface 43A of the base insulating layer 43 can be appropriately resin-etched, and adjustment thereof is easy.
[0048]
Next, an insulating layer film made of the same material as that of the base resin insulation layer 43 is pasted on the wiring layer 47 and the base resin insulation layer 43 to form a resin insulation layer 48 as shown in FIG.
Thereafter, the above process is repeated, and a desired number of wiring layers and resin insulating layers are alternately laminated to complete a printed wiring board.
[0049]
As described above, according to the manufacturing method of the present embodiment, when the surface 47A of the wiring layer 47 is roughened by etching in the etching roughening step, a part of the surface 47A remains in a granular state between the wiring layers 47 and 47. Even when it adheres to the exposed surface 43A of the underlying resin insulation layer 43, the copper fine particles 47B can be removed by the resin etching process. Accordingly, it is possible to manufacture a highly reliable printed wiring board in which no leak failure occurs between the wiring layers 47 and 47.
[0050]
( Embodiment 3 )
Then Third The embodiment will be described with reference to FIGS. 11 and 12. FIG. In the manufacturing method of the present embodiment, the wiring layer 67 is formed by the subtractive method. Embodiments 1 and 2 And different. Therefore, the above Embodiments 1 and 2 The description of the same part as in FIG.
First, the above Reference form Prepare the same laminated substrate 62 as above, Reference form and Embodiments 1 and 2 Similarly to the above, in the base insulating layer roughening step, the surface 63A of the base resin insulating layer 63 of the laminated substrate 62 is roughened.
[0051]
Next, as shown in FIG. 11A, electroless copper plating is performed on the entire surface to form an electroless plating layer 64 having a thickness of 0.7 μm. On the surface 64A of the electroless plating layer 64, Reference form and Embodiment 1 In the same manner, the same level of irregularities as the surface 63A of the base resin insulation layer 63 is formed. Subsequently, electrolytic copper plating is applied to the entire surface 64A of the electroless plating layer 64 to form an electrolytic plating layer 66 having a thickness of 20 μm.
[0052]
Next, a dry film is attached to the surface 66A of the electrolytic plating layer 66, and exposure and development are performed using a predetermined pattern. As shown in FIG. 11B, an etching resist film 65 is formed on a portion corresponding to the wiring layer. Form.
Thereafter, as shown in FIG. 11C, the electrolytic plating layer 66 and the electroless plating layer 64 exposed from the etching resist film 65 are removed by etching.
After the etching, the etching resist film 65 is peeled off, and wiring layers 67 and 67 are formed as shown in FIG.
[0053]
Next, in the etching roughening step, as shown in FIG. 12A, the surface 67A of the wiring layer 67 is roughened by treating with a roughening solution containing formic acid for 70 seconds. Also in the present embodiment, by using a roughening solution containing formic acid, the surface 67A of the wiring layer 67 can be brought into a good roughened state with severe undulations. Further, in this etching roughening step, the copper fine particles 67 </ b> B may be peeled off from the wiring layer 67 and may adhere to the base resin insulating layer 63 between the wiring layers 67 and 67.
[0054]
Next, in the resin etching process, resin etching is performed with a resin etching solution containing potassium permanganate at 80 ° C. for 1 minute, and as shown in FIG. 12B, the underlying resin insulation layer exposed between the wiring layers 67 and 67 is obtained. The surface layer portion 63 is etched by a resin having a depth of 4 μm. By this resin etching, it is possible to remove the copper fine particles 67B peeled off from the wiring layer 67 and adhered on the base resin insulating layer 63 during the etching roughening step.
[0055]
Also in this embodiment, since the depth of the resin etching is 4 μm, which is 1 μm or more, the copper fine particles 67B that cause the leakage failure can be surely removed. On the other hand, since the resin etching is performed by 4 μm of 7 μm or less, the base resin insulation layer 63 is not greatly scraped off, and the surface roughness of the base resin insulation layer 63 is not significantly reduced, and the base resin insulation layer 63 and the wiring layer 67 are not degraded. And the adhesion strength between the underlying resin insulation layer 63 and the resin insulation layer laminated later can be maintained high.
Further, since a resin etching solution containing potassium permanganate is used, the surface 63A of the base insulating layer 63 can be appropriately resin-etched, and adjustment thereof is easy.
[0056]
Next, an insulating layer film made of the same material as that of the base resin insulating layer 63 is pasted on the wiring layer 67 and the base resin insulating layer 63 to form a resin insulating layer 68 as shown in FIG.
Thereafter, the above process is repeated, and a desired number of wiring layers and resin insulating layers are alternately laminated to complete a printed wiring board.
[0057]
As described above, according to the manufacturing method of the present embodiment, when the surface 67A of the wiring layer 67 is roughened by etching in the etching roughening step, a part of the surface 67A remains in a granular state between the wiring layers 67 and 67. Even when it adheres to the exposed surface 63A of the underlying resin insulation layer 63, the copper fine particles 67B can be removed by the resin etching process. Accordingly, it is possible to manufacture a highly reliable printed wiring board that does not cause a leak failure between the wiring layers 67 and 67.
[0058]
In the above, the present invention has been described with reference to each embodiment, but the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. .
For example, in each of the embodiments described above, a method for manufacturing a printed wiring board including a resin insulating layer and a wiring layer on both surfaces of the core substrate has been described. However, a plurality of insulating layers and wiring layers are alternately stacked without a core substrate. The present invention can be similarly applied to the production of the printed wiring board.
[Brief description of the drawings]
[Figure 1] Reference form FIG. 2 is a cross-sectional view of a laminated substrate.
[Figure 2] Reference form It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the partial expanded sectional view of the base resin insulation layer of a laminated substrate, (b) shows the state which roughened the surface of the base resin insulation layer. Show.
[Fig. 3] Reference form It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which formed the electroless-plating layer, (b) shows the state which formed the resist film, (c) shows the electrolytic copper plating layer The state which formed is shown.
[Fig. 4] Reference form It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which formed the wiring layer, (b) shows the state which carried out the resin etching of the surface layer part of the base resin insulation layer between wiring layers, c) shows a state in which the surface of the wiring layer is roughened.
[Figure 5] Reference form It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which laminated | stacked the resin insulation layer, (b) shows the state which roughened the surface of the resin insulation layer.
[Fig. 6] Reference form FIG. 2 is a cross-sectional view of a printed wiring board.
[Fig. 7] Embodiment 1 It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which formed the electroless-plating layer on the base resin insulation layer, (b) shows the state which formed the resist film, (c ) Shows a state where an electrolytic copper plating layer is formed, and (d) shows a state where a wiring layer is formed.
[Fig. 8] Embodiment 1 It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which etched and roughened the surface of the wiring layer, (b) is the state which resin-etched the surface layer part of the foundation | substrate resin insulation layer between wiring layers (C) shows a state in which a resin insulating layer is laminated.
FIG. 9 Embodiment 2 It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which formed the resist film on the base resin insulation layer, (b) shows the state which formed the electroless copper plating layer, c) shows a state in which a wiring layer is formed.
FIG. 10 Embodiment 2 It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which etched and roughened the surface of the wiring layer, (b) is the state which resin-etched the surface layer part of the foundation | substrate resin insulation layer between wiring layers (C) shows a state in which a resin insulating layer is laminated.
FIG. 11 Embodiment 3 It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which formed the electroless-plating layer and the electroplating layer on the base resin insulation layer, (b) formed the etching resist film (C) shows a state where an unnecessary plated layer is removed by etching, and (d) shows a state where a wiring layer is formed.
FIG. Embodiment 3 It is a figure which shows the manufacturing method of the printed wiring board which concerns on this, (a) shows the state which etched and roughened the surface of the wiring layer, (b) is the state which resin-etched the surface layer part of the foundation | substrate resin insulation layer between wiring layers (C) shows a state in which a resin insulating layer is laminated.
13A and 13B are diagrams illustrating a method for manufacturing a printed wiring board according to the prior art, in which FIG. 13A shows a state in which an electroless plating layer is formed on a base resin insulating layer, and FIG. 13B shows a resist film formed. (C) shows a state in which an electrolytic plating layer is formed.
14A and 14B are diagrams showing a method for manufacturing a printed wiring board according to the prior art, in which FIG. 14A shows a state in which a wiring layer is formed, FIG. 14B shows a state in which the surface of the wiring layer is roughened, c) shows a state in which a resin insulating layer is laminated.
[Explanation of symbols]
1 Printed wiring board
2, 22, 42, 62 Laminated substrate
3, 23, 43, 63 Underlying resin insulation layer
3A, 23A, 43A, 63A (underlying resin insulation layer) surface
4, 24, 44, 64 Electroless plating layer
6, 26, 66 Electrolytic plating layer
7, 27, 47, 67 Wiring layer
7A, 27A, 47A, 67A (wiring layer) surface
8, 28, 48, 68 Resin insulation layer

Claims (4)

A method of manufacturing a printed wiring board having a base resin insulating layer, a wiring layer disposed thereon, and a resin insulating layer disposed thereon,
Etching roughening step of etching and roughening the surface of the wiring layer after forming the wiring layer;
After the etching roughening step, before laminating the resin insulating layer, a resin etching step of etching the surface of the base resin insulating layer exposed between the wiring layers;
A method for manufacturing a printed wiring board, comprising: It is a manufacturing method of the printed wiring board according to claim 1 ,
In the resin etching step, the depth of the resin etching of the surface of the base resin insulating layer is 1 μm or more and 7 μm or less. It is a manufacturing method of the printed wiring board according to claim 1 or 2 ,
The method of manufacturing a printed wiring board is characterized in that the etching roughening step etches and roughens the surface of the wiring layer with a roughening solution containing formic acid. It is a manufacturing method of the printed wiring board according to any one of claims 1 to 3 ,
The method for manufacturing a printed wiring board, wherein the resin etching step includes etching the base resin insulating layer with a resin etching solution containing at least one of potassium permanganate and sodium permanganate.

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