JPS6311678A - Electroless copper plating method - Google Patents

Abstract

PURPOSE:To prevent the deposition of copper on a resist formed on the surface of an insulating substrate except the part on which conductor wiring is formed by dividing a plating stage into two stages and carrying out plating with a plating soln. having lowered activity in the 1st stage. CONSTITUTION:An electroless copper plating soln. contg. copper ions, a complexing agent, a reducing agent, a pH adjusting agent, water, alpha,alpha'-dipyridyl and polyoxyethylene ether is prepd. A resist is formed on the surface of an insulating substrate except the part on which conductor wiring is formed. Plating is then carried out with the plating soln. in two stages. In the 1st stage, the activity of the plating soln. is lowered by reducing the concn. of at least the reducing agent in the soln. so as to prevent the deposition of copper on catalyst particles sticking to the resist and the substrate is immersed in the plating soln. having the lowered activity for <=5hr.

Description

Translated fromJapanese

【発明の詳細な説明】（産業上の利用分野）本発明は無電解銅めっき法に関する。[Detailed description of the invention](Industrial application field)The present invention relates to an electroless copper plating method.

（従来の技術）無電解銅めっき液を用いてプリント配線板を製造する方
法として、無電解銅めっき反応の触媒を含有する接着剤
層付き絶縁板を用い、４体配線となる部分以外にめっき
レジスト形成し、導体配線と接着剤層付き＃！！縁板と
の接着力を付与するために接着剤層表面を粗化した後、
無電解銅めっきで導体配線を形成する方法がある。(Prior art) As a method of manufacturing printed wiring boards using an electroless copper plating solution, an insulating board with an adhesive layer containing a catalyst for an electroless copper plating reaction is used, and areas other than those that will become four-body wiring are plated. # with resist formed, conductor wiring and adhesive layer! ! After roughening the adhesive layer surface to provide adhesive strength with the edge plate,
There is a method of forming conductor wiring using electroless copper plating.

（発明が解決しようとする問題点）この方法は、めっきレジストの溝部分にめっきで導体を
形成するのでめっきレジストの解像度まで導体寸法精度
をあげられること、無電解銅めっきは電気めっきに比べ
てめっきのつきまわり性が優れているので小径スルーホ
ール壁ににも均一なめっぎ膜厚が得らｎること、この２
の特長のためめっきレジストを形成した後無電解銅めっ
きによって導体を形成する方法はプリント配線板の配線
の高密度化に適している。(Problems to be Solved by the Invention) This method forms conductors by plating in the grooves of the plating resist, so the dimensional accuracy of the conductor can be improved to the resolution of the plating resist, and electroless copper plating is superior to electroplating. The second advantage is that the plating has excellent coverage, so a uniform plating film thickness can be obtained even on the walls of small-diameter through holes.
Because of this feature, the method of forming conductors by electroless copper plating after forming a plating resist is suitable for increasing the density of wiring on printed wiring boards.

しかし、無電解銅めっきは非配線部分（レジスト上）Ｋ
もめりきが析出する場合があり、この不良発生が？ｉ６
密度配線めっきをする上での問題でありた。However, in electroless copper plating, the non-wiring area (on the resist) K
In some cases, grains may precipitate, and this defect may occur. i6
This was a problem when performing high-density wiring plating.

本発明は非配線部分（レジスト上ノヘ鋼析出不良が発生
しない無電Ｍ銅めっき法を提供するものである。The present invention provides an electroless M copper plating method that does not cause defects in steel deposition on non-wiring areas (on resists).

（問題点を解決するための手段）本発明は絶碌性基板表面の導体配線となる部分以外にめ
っきレジストを形成した後、無電解銅めっきて導体配ｌ
！Ａｔ−形成する方法に於て、使用する無電解銅めっき
液が銅イオン、銅イオンの錯化剤、還元剤、田調整剤、
水、αα′−ジピリジルおよび一般式Ｒｓ　Ｏ＋　ＣＨ
２ＣＨｓ　Ｏ＋ｎ　Ｒｘ　（Ｒ１−Ｒ２は水素原子、炭
素素１〜１８のアルキル基、アルケニル基である。但し
Ｒ１，Ｔｏの両方が水素原子の場合は含まない。）で表
わされるポリオキシエチレンエーテルを含有する無電解
銅めっき液であること、＃を解鋼めっき工程を２工程に
分けること、第１工程の無電解銅めっき液の銅イオン、
田調整剤および還元剤の日歩くとも還元剤１度を第２工
程の無電解銅めっき液の濃度よりも低！Ｉ度にすること
によってめっき活性を下げること、第１工程の無電解銅
めっき液への浸漬時間が５時間以下であることを特徴と
する無電解銅めっき法である。(Means for Solving the Problems) The present invention forms a plating resist on the surface of an insulated substrate other than the portion that will become the conductor wiring, and then performs electroless copper plating to form the conductor wiring.
! In the At-forming method, the electroless copper plating solution used contains copper ions, a copper ion complexing agent, a reducing agent, a field conditioner,
Water, αα′-dipyridyl and general formula Rs O+ CH
Contains polyoxyethylene ether represented by 2CHs O+n Rx (R1-R2 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkenyl group. However, this is not included when both R1 and To are hydrogen atoms.) It is an electroless copper plating solution that # is divided into two steps, copper ions in the electroless copper plating solution in the first step,
The concentration of the reducing agent is lower than the concentration of the electroless copper plating solution in the second step! This electroless copper plating method is characterized in that the plating activity is lowered by reducing the plating activity to 1 degree, and that the immersion time in the electroless copper plating solution in the first step is 5 hours or less.

本発明で用いるプリント配線基板は、例えはめつぎ皮膜
との接着力が付与でさる接着剤ノｄ付絶縁板であり、そ
の接着剤層にはＰｄなどの無電解銅めっき反応を開始さ
せるめっき触媒を含有させたものが好ましい。めっきレ
ジストは紫外線硬化型のドライフィルム、紫外線硬化型
インク、熱硬化型インクなどが用いらｎる。The printed wiring board used in the present invention is an insulating board with an adhesive bonded to it, for example, to provide adhesion to a plating film, and the adhesive layer is coated with a plating catalyst such as Pd that starts the electroless copper plating reaction. Preferably, it contains. As the plating resist, an ultraviolet curable dry film, an ultraviolet curable ink, a thermosetting ink, etc. are used.

無電解銅めっき液は銅イオン、鋼イオンの錯化剤、還元
剤、■調整剤、水、αα′−ジピリジルおよび一般式Ｒ
１０（−ＣＨｚＣＨｚＯ＋ｎＲｚ　（Ｒ１、Ｒ２）工水
素原子、炭素累１〜１８のアルキル基、アルケニル基で
ある。但しＲ，、Ｒ２の両方が水素原子の場合は含まな
い。）で表わされるポリオキシエチレンエーテルを含有
する無電解銅めっき液であり、一般のプリント配線板の
導体厚さである３０μｍ以上までめっきが可能であり、
またプリント配線板の導体としての信頼性を有するもの
である。The electroless copper plating solution contains copper ions, a complexing agent for steel ions, a reducing agent, a regulator, water, αα′-dipyridyl, and the general formula R
Polyoxyethylene represented by 10 (-CHzCHzO+nRz (R1, R2) is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkenyl group. However, if both R and R2 are hydrogen atoms, this is not included.) It is an electroless copper plating solution containing ether, and is capable of plating to a conductor thickness of 30 μm or more, which is the conductor thickness of general printed wiring boards.
It also has reliability as a conductor for printed wiring boards.

従来、無電解銅めっきし一工程でおこなツ”Ｃいたが、
本発明では２工程に分ける。第２工程のめっき液組成は
、従来おこなっているめっき液組成と同じであり、第１
工程、第２工程のめっぎで得らｎるめっき膜厚の７割以
上をこの工程でめっきする。Conventionally, electroless copper plating was done in one process, but
In the present invention, the process is divided into two steps. The plating solution composition in the second step is the same as the plating solution composition used in the conventional plating solution.
70% or more of the plating film thickness obtained in the second step is plated in this step.

第１工程のめりき液組成は、銅イオン、…調整剤お工び
還元剤８度の８少くとも還元剤を第２工程の無電解銅め
っき液の＃度よりも低濃度にすることによってめっき活
性を下げる。そのａ度は第２めっき工程のめつき析出速
度の７割以下に第１めっき工程のめっぎ析出速度が下る
工うにする。第１工程のめっき時間は５時間以下である
。５時間を越えると、めっきの不析出個所が発生したり
めっき皮膜の％性が低下したりする。また短いと非配線
部分へのめっき析出の抑制効果が低下する。したがって
、６０分から５時間の間て選ばれる。The composition of the plating solution in the first step is copper ion,...adjuster, reducing agent, and reducing agent. Reduce activity. The a degree is set such that the plating precipitation rate in the first plating step is 70% or less of the plating precipitation rate in the second plating step. The plating time in the first step is 5 hours or less. If the time exceeds 5 hours, areas where the plating does not precipitate may occur or the percentage quality of the plating film may decrease. Moreover, if it is short, the effect of suppressing plating precipitation on non-wiring portions will be reduced. Therefore, a period between 60 minutes and 5 hours is chosen.

（作用）レジスト上へのめっぎ析１１：ｌは捕々の検討の結果、
接着剤層付絶縁板にめっきレジストを形成した後、めっ
き導体と基板との接着力を付与するためにおこなった接
Ｍ剤１−の粗化工程でＰｄなどのめっき触媒を含有して
いる粗化脆弱層が作らｎこの脆弱層からはが八た粒子が
レジスト上に付着し、この粒子に含ま八るめっき触媒を
もとにしてめっきが析出するものと推定さｎた。(Function) As a result of extensive research, plating analysis 11:1 on resist was conducted.
After forming a plating resist on an insulating board with an adhesive layer, a roughening agent containing a plating catalyst such as Pd is used in the roughening process of the contacting agent 1-, which is carried out to provide adhesive strength between the plated conductor and the substrate. It is presumed that a brittle layer is formed, particles are attached to the resist from this brittle layer, and plating is precipitated based on the plating catalyst contained in these particles.

本発明で第１工程のめっぎ治性全下げることに工つてレ
ジスト上へのめっぎ析出が無くなった。In the present invention, by completely reducing the plating curability in the first step, there is no plating precipitation on the resist.

第１工程の低活性めっき液でを工脆弱層からできた粒子
に含まｎるめりき触媒ではめっきが析出しないこと、第
１工程のめっき液への浸漬時間中にレジスト上に付着し
た脆弱層からできた程子が脱落するものと思わｎる。次
に第２工程のめりき液に浸漬し、所望のめっき厚さまで
めっきをおこなう。この方法に工ってめっきレジスト上
にめっき析出のないプリント配線板の製造が可能となる
。The plating does not precipitate with the plating catalyst contained in the particles formed from the brittle layer formed by the low-activity plating solution in the first step, and the brittle layer adheres to the resist during the immersion time in the plating solution in the first step. I think that the hodoko that was formed from this will fall off. Next, it is immersed in a second step plating solution and plated to the desired plating thickness. By using this method, it is possible to manufacture a printed wiring board without plating precipitation on the plating resist.

実施例接着剤層付絶縁板（日立化成製、商品名ＡＣＬ−Ｅ−１
６８）に紫外線硬化型ドライフィルム（日立化成製、商
品名５Ｒ−５０００）を用いてめっきレジストを形成し
た。次にクロム酸、硫酸を含む化学粗化液に浸漬しめり
ぎレジストで櫟われていない接着剤層の表面を粗化した
。Example Insulating board with adhesive layer (manufactured by Hitachi Chemical, trade name ACL-E-1
68), a plating resist was formed using an ultraviolet curing dry film (manufactured by Hitachi Chemical, trade name 5R-5000). Next, the surface of the adhesive layer that had not been roughened with the Shimerigi resist was roughened by dipping it in a chemical roughening solution containing chromic acid and sulfuric acid.

次に温度が７０±２０である組成（５）の第１工程のめ
りき液Ｔ／Ｃ３時間浸漬した。次に温度が７０±２℃で
ある組成ｔＢＪの第２工程のめっき液に１２時間浸漬し
た。めっきレジスト上への銅析出不良発生を工見られな
かった。Next, it was immersed in the first step plating solution T/C having composition (5) at a temperature of 70±20 for 3 hours. Next, it was immersed in a second step plating solution having a composition tBJ at a temperature of 70±2° C. for 12 hours. No defects in copper precipitation on the plating resist were observed.

組Ｍ、四　　組成（８１ＣｕＳＯｎ・５ＨｚＯ（ｇ／ｌ　）　　　　　１０　　
　１０ＥＤＴＡ−２Ｎａ（ｇ／ｌ）　　　　　　４０　
　　　　４０ＦＩ′ｌ（ＮａＯＨｋ用いて調整）　　　
　　１２．１　　　　１２．４３７％ｃＨ２（１１元剤
）ＣｒｌＪｌ／Ｉ）　　　２．１）　　　　　３．５α
α′−ジピリジルＣａ１７１　）　　　　　　３０　　
　　　３０ポリオキシエチレンモノメチルエーテル＜ｇ
／Ａ）　　５　　　　　　　　　５純　水　　　　　　
　　　　　総量で１１になる童　同左めっき析出速度（
ａｍ／ｈ　）　　　　　１．６　　　　２．５比較例実施例と同様の材料、工程で粗化までおこない次に実施
例の組成（ＢＪの条件のめっき液に１４時間浸漬してめ
っきをおこなった。Group M, 4 Composition (81 CuSOn・5HzO (g/l) 10
10EDTA-2Na (g/l) 40
40FI'l (adjusted using NaOHk)
12.1 12.437%cH2 (11 element) CrlJl/I) 2.1) 3.5α
α'-dipyridyl Ca171) 30
30 polyoxyethylene monomethyl ether <g
/A) 5 5 pure water
The total amount is 11. The same plating deposition rate on the left (
am/h) 1.6 2.5 Comparative Example The same materials and steps as in the example were used until roughening, and then plating was performed by immersing the sample in a plating solution having the composition of the example (BJ conditions) for 14 hours.

めっきレジスト上への銅析出不良発生率は３０％であっ
た。（発生′４はプリント配線板５０枚製造し析出不良
が発生したものの百分率である）（発明の効果）The incidence of defective copper deposition on the plating resist was 30%. (Occurrence '4 is the percentage of defective deposition that occurred when 50 printed wiring boards were manufactured.) (Effects of the invention)

Claims (1)

Translated fromJapanese

【特許請求の範囲】[Claims]１、絶縁性基板表面の導体配線となる部分以外にめっき
レジストを形成した後、無電解銅めっきで導体配線を形
成する無電解銅めっき法に於て使用する無電解銅めっき
液が銅イオン、銅イオンの錯化剤、還元剤、ｐＨ調整剤
、水、αα′−ジピリジルおよび一般式Ｒ＿１Ｏ■ＣＨ
＿２ＣＨ＿２Ｏ■＿ｎＲ＿２（Ｒ＿１、Ｒ＿２は水素原
子、炭素素１〜１８のアルキル基、アルケニル基である
。但しＲ＿１、Ｒ＿２の両方が水素原子の場合は含まな
い。）で表わされるポリオキシエチレンエーテルを含有
する無電解銅めっき液であること、無電解銅めっき工程
を２工程に分けること、第１工程の無電解銅めっき液の
銅イオン、ｐＨ調整剤および還元剤の内少くとも還元剤
濃度を第２工程の無電解銅めっき液の濃度よりも低濃度
にすることによってめっき活性を下げること、第１工程
の無電解銅めっき液への浸漬時間が５時間以下であるこ
とを特徴とする無電解銅めっき法。1. The electroless copper plating solution used in the electroless copper plating method, in which conductor wiring is formed by electroless copper plating after forming a plating resist on the surface of the insulating substrate other than the part that will become the conductor wiring, contains copper ions, Copper ion complexing agent, reducing agent, pH adjuster, water, αα′-dipyridyl and general formula R_1O■CH
Contains polyoxyethylene ether represented by _2CH_2O■_nR_2 (R_1 and R_2 are a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkenyl group. However, if both R_1 and R_2 are hydrogen atoms, this is not included.) The electroless copper plating solution should be divided into two steps, and the concentration of at least the reducing agent of the copper ions, pH adjuster, and reducing agent in the electroless copper plating solution in the first step should be An electroless method characterized by lowering the plating activity by lowering the concentration of the electroless copper plating solution than the concentration of the electroless copper plating solution in the second step, and in that the immersion time in the electroless copper plating solution in the first step is 5 hours or less. Copper plating method.