JP4197805B2 - Multilayer printed wiring board and manufacturing method thereof - Google Patents

Description

【００６３】
上記表１の結果より明らかなように、実施例の多層プリント配線板は、加熱試験やヒートサイクル試験を行った後も、導体回路とバイアホールとの間の抵抗変化率は小さく、導体回路と層間樹脂絶縁層との剥離は見られなかったのに対し、比較例の多層プリント配線板は、抵抗変化率が大きいか、または、試験後に剥離が発生していた。
【００６４】
【発明の効果】
以上説明したように本発明の多層プリント配線板は、層間樹脂絶縁層として、シクロオレフィン系樹脂を使用しているので、誘電率や誘電正接が小さく、そのためにＧＨｚ帯域の高周波信号を用いた場合にも、信号遅延や信号エラーが発生しにくく、また、剛性等の機械的特性に優れるため、導体回路同士の接続の信頼性が高く、導体回路と層間樹脂絶縁層をとの密着性にも優れる。
【００６５】
また、本発明の多層プリント配線板の製造方法は、導体回路上にシクロオレフィン系樹脂シートをラミネートすることにより層間樹脂絶縁層を形成するので、溶剤等を用いる必要がなくなり、製造工程が簡易化され、容易に多層プリント配線板を製造することができる。
【図面の簡単な説明】
【図１】（ａ）〜（ｄ）は、本発明の多層プリント配線板の製造工程の一部を示す縦断面図である。
【図２】（ａ）〜（ｄ）は、本発明の多層プリント配線板の製造工程の一部を示す縦断面図である。
【図３】（ａ）〜（ｄ）は、本発明の多層プリント配線板の製造工程の一部を示す縦断面図である。
【図４】（ａ）〜（ｃ）は、本発明の多層プリント配線板の製造工程の一部を示す縦断面図である。
【図５】 （ａ）〜（ｃ）は、本発明の多層プリント配線板の製造工程の一部を示す縦断面図である。
【符号の説明】
１ 基板
２ 層間樹脂絶縁層
３ めっきレジスト
４ 下層導体回路
４ａ 粗化面
５ 上層導体回路
６ バイアホール用開口
７ バイアホール
８ 銅箔
９ スルーホール
９ａ 粗化面
１０ 樹脂充填剤
１２ Ｎｉ−Ｃｕ合金層
１３ 電気めっき膜
１４ ソルダーレジスト層
１５ ニッケルめっき膜
１６ 金めっき膜
１７ はんだバンプ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a multilayer printed wiring board having an interlayer resin insulating layer made of a cycloolefin resin having a low dielectric constant and excellent mechanical properties such as rigidity.
[0002]
[Prior art]
A multilayer printed wiring board called a so-called multilayer build-up wiring board is manufactured by a semi-additive method or the like. Copper is laid on a resin substrate reinforced with a glass cloth of about 0.6 to 1.5 mm called a core. It is produced by alternately laminating conductive circuits and interlayer resin insulation layers by the method described above. The connection between the conductor circuits through the interlayer resin insulating layer of the multilayer printed wiring board is made by via holes.
[0003]
Conventionally, a build-up multilayer printed wiring board is manufactured by a method disclosed in, for example, Japanese Patent Laid-Open No. 9-130050.
That is, first, a through-hole is formed in a copper-clad laminate on which a copper foil is affixed, and then a through-hole is formed by performing an electroless copper plating process. Subsequently, the surface of the substrate is etched into a conductor pattern to form a conductor circuit, a roughened surface is formed on the surface of the conductor circuit by electroless plating, etching, etc., on the conductor circuit having the roughened surface. After the interlayer resin insulation layer is formed, exposure and development processes are performed, or via-hole openings are formed by laser treatment, and then the interlayer resin insulation layer is formed through UV curing and main curing.
[0004]
Further, after roughening the interlayer resin insulation layer, a thin electroless plating film is formed on the formed roughened surface, a plating resist is formed on the electroless plating film, and then thickened by electrolytic plating. After the plating resist is peeled off, etching is performed to form a conductor circuit connected to the underlying conductor circuit by a via hole.
[0005]
After repeating this, a solder resist layer for protecting the conductor circuit is formed as the outermost layer, an opening is formed in the solder resist layer, and the conductor layer in the opening is plated to form a pad, and then a solder bump By forming, a build-up multilayer printed wiring board is manufactured.
[0006]
However, since the multilayer printed wiring board manufactured in this way uses a mixture of an epoxy resin, an acrylic resin, or the like for the interlayer resin insulating layer, the dielectric constant is as high as 3.5 or more in the GHz region.
Therefore, when an LSI chip or the like using a high frequency signal in the GHz band is mounted, there is a problem that signal delay and signal error are likely to occur due to the high dielectric constant of the interlayer resin insulation layer. It was.
[0007]
[Problems to be solved by the invention]
In order to solve such problems, a printed wiring board using a linear polyolefin resin as an interlayer resin insulating layer has been proposed. In this printed wiring board, although the dielectric constant of the interlayer resin insulation layer is reduced, the interlayer resin insulation layer itself is too soft, so that the formed conductor circuit is likely to sink into the interlayer resin insulation layer. There was a problem that problems in connection were likely to occur and the reliability of the printed wiring board was low.
[0008]
Moreover, when forming an interlayer resin insulation layer using the above-mentioned linear polyolefin resin, an interlayer resin insulation layer was formed by pressure bonding and laminating a resin sheet on a conductor circuit, but the film is too soft. There was also a problem that it was difficult to handle.
[0009]
The present invention has been made in order to solve such problems of the prior art, and the object thereof is to reduce the signal delay and signal even when a high frequency signal in the GHz band is used because the dielectric constant and dielectric loss tangent are small. An object of the present invention is to provide a method for producing a multilayer printed wiring board having an interlayer resin insulation layer that is less likely to cause errors and is excellent in mechanical properties such as rigidity and has high reliability in connection between conductor circuits.
[0010]
[Means for Solving the Problems]
As a result of diligent research toward the realization of the above object, the present inventors have used cycloolefin resins, especially thermosetting cycloolefin resins, in the interlayer resin insulation layer, thereby reducing the above-described low dielectric constant and low dielectric constant. It has been found that an interlayer resin insulation layer that sufficiently satisfies the required characteristics can be formed with respect to electrical characteristics such as dielectric loss tangent and mechanical characteristics such as rigidity. I came up with it.
[0013]
That is, the method for manufacturing a multilayer printed wiring board according to the present invention is a method for manufacturing a multilayer printed wiring board in which a conductor circuit and a resin insulating layer are sequentially formed on a substrate, and these conductor circuits are connected via via holes. ,
On the conductor circuit formed on both sides of the substrate,
An interlayer resin insulation layer forming step of forming an interlayer resin insulation layer by vacuum compression laminating a film made of cycloolefin resin ;
By irradiating the interlayer resin insulation layer with the excimer laser beam through a mask having a plurality of through holes formed in a portion corresponding to the opening for via holes, the interlayer resin insulation layer is formed with a plurality of via holes at a time. and the via-hole opening forming step of forming an opening,
A roughening treatment step of roughening the surface of the interlayer resin insulation layer having the via hole opening;
An intermediate layer forming step of forming an intermediate layer made of Ni, Ti, Pd or Ni-Cu alloy on the roughened interlayer resin insulation layer;
Forming a via hole in the opening for the via hole in the interlayer resin insulation layer via the intermediate layer, and forming a conductor circuit on the interlayer resin insulation layer via the intermediate layer ; Is performed at least once.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
In the multilayer printed wiring board of the present invention, a conductor circuit and a resin insulating layer are sequentially formed on the substrate, and these conductor circuits are connected via via holes.
The resin insulation layer is made of a cycloolefin resin.
[0016]
According to the multilayer printed wiring board of the present invention, since the interlayer resin insulation layer is made of a cycloolefin resin, the dielectric constant and the dielectric loss tangent are larger than those of an interlayer resin insulation layer made of epoxy resin or the like. It is possible to prevent signal errors caused by signal propagation delays and signal transmission losses.
[0017]
In addition, since the cycloolefin resin has high mechanical properties, particularly high rigidity, it is possible to form a conductor circuit on a firm interlayer resin insulation layer, so that the connection reliability between the conductor circuits is sufficient. Can be secured.
[0018]
In addition, the cycloolefin-based resin also has excellent adhesion to the conductor circuit, so it is possible to prevent the interlayer resin insulation layer from peeling off from the conductor circuit, and the occurrence of cracks in the interlayer resin insulation layer due to peeling. Etc. can also be prevented.
Furthermore, since the cycloolefin resin has a low water absorption rate, the electrical insulation between the conductor circuits is increased and the reliability is improved.
[0019]
The type of the cycloolefin resin is not particularly limited, but the dielectric constant at 1 GHz is preferably 3.0 or less, and the dielectric loss tangent is preferably 0.01 or less. The dielectric constant is more preferably 2.4 to 2.7.
By using such a low dielectric constant, it is possible to prevent signal errors due to signal propagation delay, signal transmission loss, and the like.
[0020]
The cycloolefin-based resin is preferably a homopolymer or copolymer of a monomer composed of 2-norbornene, 5-ethylidene-2-norbornene, or a derivative thereof. Examples of the derivative include those in which an amino group for forming a bridge, a maleic anhydride residue, or a maleic acid-modified one is bonded to the cycloolefin such as 2-norbornene.
Examples of the monomer for synthesizing the copolymer include ethylene and propylene.
[0021]
The cycloolefin-based resin may be a mixture of two or more of the above-described resins, or may include a resin other than the cycloolefin-based resin.
Moreover, when the said cycloolefin type resin consists of a copolymer, a block copolymer may be sufficient and a random copolymer may be sufficient.
[0022]
The cycloolefin resin is preferably a thermosetting cycloolefin resin. This is because by heating to form a crosslink, the rigidity becomes higher and the mechanical properties are improved.
The glass transition temperature (Tg) of the cycloolefin resin is preferably 130 to 200 ° C.
[0023]
The cycloolefin resin may be a resin sheet (film) that has already been molded, and a monomer or a low molecular weight polymer having a certain molecular weight is dispersed in a solvent such as xylene or cyclohexane. It may be in an uncured solution state.
In the case of a resin sheet, so-called RCC (RESIN COATED copper) may be used.
[0024]
The cycloolefin-based resin may not contain a filler or the like, or may contain a flame retardant such as aluminum hydroxide, magnesium hydroxide, or phosphate ester.
[0025]
Next, the manufacturing method of the multilayer printed wiring board using such a cycloolefin type resin is demonstrated.
[0026]
(1) First, a wiring substrate having a lower layer conductor circuit on the surface of a resin substrate is produced.
As the resin substrate, a resin substrate having inorganic fibers is desirable, and specific examples include a glass cloth epoxy substrate, a glass cloth polyimide substrate, a glass cloth bismaleimide-triazine resin substrate, a glass cloth fluororesin substrate, and the like.
Moreover, you may use the copper clad laminated board which stuck the copper foil on both surfaces of the said resin substrate.
[0027]
Usually, a through hole is provided in the resin substrate with a drill, and electroless plating is applied to the wall surface of the through hole and the copper foil surface to form a through hole. As the electroless plating, copper plating is preferable. Furthermore, electroplating may be performed for thickening the copper foil. As this electroplating, copper plating is preferable.
Thereafter, the inner wall or the like of the through hole may be roughened, the through hole may be filled with a resin paste or the like, and a conductive layer covering the surface may be formed by electroless plating or electroplating.
[0028]
Examples of the roughening treatment include blackening (oxidation) -reduction treatment, spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, treatment with Cu—Ni—P needle-shaped alloy plating, and the like.
Through the above steps, an etching resist is formed on the copper solid pattern formed on the entire surface of the substrate by using a photolithography technique, and then etching is performed to form a lower conductor circuit. Thereafter, if necessary, a resin circuit or the like may be filled in a portion that has been etched to form a recess by forming a conductor circuit.
(2) Next, a roughening process is performed on the formed lower conductor circuit as necessary. As a roughening treatment method, the above-described methods, that is, blackening (oxidation) -reduction treatment, spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, treatment with Cu-Ni-P needle alloy plating, and the like are included. Can be mentioned.
In addition, a layer made of resin is formed on the surface of the lower conductor circuit by immersing the substrate on which the lower conductor circuit is formed in a solution in which the resin component is dissolved without subjecting the lower conductor circuit to roughening. Adhesion with the interlayer resin insulation layer formed on the substrate may be ensured.
[0029]
(3) Next, an interlayer resin insulating layer made of the cycloolefin-based resin is formed on both surfaces of the wiring board having the lower conductor circuit manufactured in (2).
This interlayer resin insulation layer is formed by applying an uncured liquid for forming a cycloolefin-based resin and then curing it by heating or by laminating the resin sheet under vacuum pressure bonding while heating. In view of simplicity, a method of laminating a resin sheet is preferable. As heating conditions in this case, 100-180 degreeC and 0.5-20 minutes are preferable.
[0030]
(4) Next, a via hole opening is provided by irradiating the interlayer resin insulation layer with laser light. In this case, examples of the laser beam used include a carbon dioxide (CO ₂ ) laser, an ultraviolet laser, and an excimer laser. Among these, an excimer laser and a short pulse carbon dioxide laser are preferable.
[0031]
An excimer laser can form a large number of via holes at a time by using a mask having a through hole formed in a portion where a via hole is formed, and a short pulse carbon dioxide laser. This is because the resin remaining in the opening is small and the damage to the resin on the periphery of the opening is small.
The through hole of the mask needs to be a perfect circle in order to make the spot shape of the laser beam a perfect circle, and the diameter of the through hole is preferably about 0.1 to 2 mm.
[0032]
When the opening is formed with laser light, particularly when a carbon dioxide laser is used, it is desirable to perform desmear treatment. The desmear treatment can be carried out using an oxidizing agent comprising an aqueous solution such as chromic acid or permanganate. Alternatively, the treatment may be performed by oxygen plasma, mixed plasma of CF ₄ and oxygen, corona discharge, or the like. Further, the surface can be modified by irradiating with ultraviolet rays using a low-pressure mercury lamp.
[0033]
(5) The interlayer resin insulation layer may be formed with a metal layer on it without performing a roughening treatment or the like, and its surface may be roughened by plasma treatment or treatment with acid or the like. After forming, a metal layer may be formed.
When plasma treatment is performed, in order to ensure adhesion between the conductor circuit formed as the upper layer and the interlayer resin insulation layer, a metal such as Ni, Ti, Pd or the like having excellent adhesion with the interlayer resin insulation layer is used. It may be formed as an intermediate layer. The intermediate layer made of the metal is preferably formed by physical vapor deposition (PVD) such as sputtering, and the thickness is preferably about 0.1 to 2.0 μm.
[0034]
(6) After the above process, a thin film layer made of metal is formed. The material of the thin film layer is preferably copper or a copper-nickel alloy. This thin film layer can be formed by a physical vapor deposition method (PVD method) or a chemical vapor deposition method (CVD method), or can be formed by electroless plating.
Examples of the PVD method include sputtering and ion beam sputtering. Examples of the CVD method include PE-CVD (Plasma Enhanced CVD) using an organic metal as a supply material.
[0035]
The thickness of this thin film is preferably 0.1 to 5 μm. The reason why such a film thickness is used is to enable etching removal without impairing the function as a conductive layer of electroplating performed later. This thin film forming step is not essential and can be omitted.
[0036]
(7) A plating resist is formed on the electroless plating film formed in (6) above.
This plating resist is formed by laminating a photosensitive dry film, followed by exposure and development.
[0037]
(8) Next, electroplating is performed using the metal thin film formed on the interlayer resin insulation layer as a plating lead to thicken the conductor circuit. The thickness of the electroplated film is preferably 5 to 30 μm.
At this time, the via hole opening may be filled with electroplating to form a filled via structure.
[0038]
(9) After forming the electroplating film, the plating resist is peeled off, and the electroless plating film and the intermediate layer existing under the plating resist are removed by etching to form an independent conductor circuit. As the electroplating, it is desirable to use copper plating.
Examples of the etchant include sulfuric acid-hydrogen peroxide aqueous solution, ammonium persulfate aqueous solution, persulfate aqueous solution such as sodium persulfate, potassium persulfate, ferric chloride, cupric chloride aqueous solution, hydrochloric acid, nitric acid, hot dilute sulfuric acid. Etc. Moreover, you may form a roughening surface simultaneously with the etching between conductor circuits using the etching liquid containing the cupric complex mentioned above and organic acid.
[0039]
(10) Thereafter, the above steps (2) to (9) are repeated to provide an upper conductor circuit, an upper layer is provided with a solder resist layer, the solder resist layer is opened, and a solder bump is provided. For example, a six-layer double-sided multilayer printed wiring board having three layers on one side is obtained.
In the following, description will be given based on examples.
[0040]
【Example】
(Example 1)
(1) A copper-laminated laminate in which 18 μm copper foil 8 is laminated on both surfaces of a substrate 1 made of glass epoxy resin or BT (bismaleimide-triazine) resin having a thickness of 1 mm was used as a starting material (FIG. 1 (a )reference). First, after drilling the copper-clad laminate, forming a plating resist, the substrate is subjected to electroless copper plating to form through holes 9, and the copper foil is patterned in accordance with a conventional method. The inner layer copper pattern (lower layer conductor circuit) 4 was formed on both sides of the substrate.
[0041]
(2) The substrate on which the lower conductor circuit 4 is formed is washed with water and dried, and then an etching solution is sprayed onto both surfaces of the substrate to spray the surface of the lower conductor circuit 4, the land surface of the through hole 9, and the inner wall. Thus, roughened surfaces 4a and 9a were formed on the entire surface of the lower conductor circuit 4 (see FIG. 1B). As an etching solution, a mixture of 10 parts by weight of imidazole copper (II) complex, 7 parts by weight of glycolic acid, 5 parts by weight of potassium chloride and 78 parts by weight of ion-exchanged water was used.
[0042]
(3) The resin filler 10 mainly composed of cycloolefin resin is applied to both sides of the substrate by using a printing machine so that it is filled between the lower conductor circuits 4 or in the through holes 9 and dried by heating. It was. That is, by this step, the resin filler 10 is filled between the lower conductor circuits 4 or in the through holes 9 (see FIG. 1C).
[0043]
(4) Resin filling the surface of the lower conductor circuit 4 and the land surface of the through-hole 9 on one side of the substrate after the above processing (3) by belt sander polishing using belt polishing paper (manufactured by Sankyo Rikagaku) Polishing was performed so that the agent 10 did not remain, and then buffing was performed to remove scratches due to the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate. And the resin filler 10 with which it filled was heat-hardened (refer FIG.1 (d)).
[0044]
In this way, the surface layer portion of the resin filler 10 filled in the through holes 9 and the like and the roughened layer 4a on the upper surface of the lower conductor circuit 4 are removed to smooth both surfaces of the substrate, and the resin filler 10 and the lower conductor circuit 4 are smoothed. Thus, a wiring board was obtained in which the side surface of the through hole 9 was firmly adhered via the roughened surface 4a, and the inner wall surface of the through hole 9 and the resin filler 10 were firmly adhered via the roughened surface 9a.
[0045]
(5) Next, the same etching solution as that used in (2) above is sprayed on both surfaces of the substrate after the processing in (4) above, and the surface of the lower conductor circuit 4 once flattened is sprayed. Then, the rough surfaces 4a and 9a were formed on the entire surface of the lower conductor circuit 4 by etching the land surfaces of the through holes 9 (see FIG. 2A).
[0046]
(6) Next, a thermosetting cycloolefin resin sheet having a thickness of 50 μm is vacuum-bonded and laminated on both surfaces of the substrate subjected to the above process at a pressure of 5 kg / cm ² while raising the temperature to 50 to 150 ° C. An interlayer resin insulation layer 2 made of an olefin resin was provided (see FIG. 2B). The degree of vacuum at the time of vacuum pressure bonding was 10 mmHg.
[0047]
(7) Next, with a CO ₂ gas laser with a wavelength of 10.4 μm, an interlayer made of cycloolefin resin under the conditions of a beam diameter of 5 mm, a top hat mode, a pulse width of 50 μs, a mask hole diameter of 0.5 mm, and three shots. A via hole opening 6 having a diameter of 80 μm was provided in the resin insulating layer 2 (see FIG. 2C). Thereafter, desmear treatment was performed using oxygen plasma.
[0048]
(8) Next, plasma processing was performed using SV-4540 manufactured by Nippon Vacuum Technology Co., Ltd., and the surface of the interlayer resin insulation layer 2 was roughened (see FIG. 2D). At this time, argon gas was used as an inert gas, and plasma treatment was performed for 2 minutes under the conditions of power 200 W, gas pressure 0.6 Pa, and temperature 70 ° C.
[0049]
(9) Next, using the same apparatus, after replacing the internal argon gas, sputtering with a Ni—Cu alloy as a target was performed under conditions of atmospheric pressure 0.6 Pa, temperature 80 ° C., power 200 W, and time 5 minutes. The Ni—Cu alloy layer 12 was formed on the surface of the polyolefin-based interlayer resin insulation layer 2. At this time, the thickness of the formed Ni—Cu alloy layer 12 was 0.2 μm (see FIG. 3A).
[0050]
(10) A commercially available photosensitive dry film is pasted on both sides of the substrate after the above treatment, a photomask film is placed, exposed at 100 mJ / cm ² , and then developed with 0.8% sodium carbonate. Then, a pattern of the plating resist 3 having a thickness of 15 μm was formed (see FIG. 3B).
[0051]
(11) Next, electroplating was performed under the following conditions to form an electroplated film 13 having a thickness of 15 μm (see FIG. 3C). In addition, with this electroplating film 13, the thickness of the portion that becomes the conductor circuit 5 and the plating filling of the portion that becomes the via hole 7 are performed in the steps described later. The additive in the electroplating aqueous solution is Kaparaside HL manufactured by Atotech Japan.
[0052]
[Electroplating aqueous solution]
Sulfuric acid 2.24 mol / l
Copper sulfate 0.26 mol / l
Additive 19.5 ml / l
[Electroplating conditions]
Current density 1 A / dm ²
Time 65 minutes Temperature 22 ± 2 ℃
[0053]
(12) Next, after removing the plating resist 3 with 5% NaOH, the Ni—Cu alloy layer 12 existing under the plating resist 3 is etched using a mixed solution of nitric acid, sulfuric acid and hydrogen peroxide. The conductive circuit 5 (including the via hole 7) having a thickness of 16 μm made of the electrolytic copper plating film 13 and the like was formed (see FIG. 3D).
[0054]
(13) Subsequently, the above steps (5) to (13) were repeated to form a further upper conductor circuit. (Refer to Drawing 4 (a)-Drawing 5 (b)).
[0055]
(14) Next, a photosensitizing agent obtained by acrylated 50% of an epoxy group of a cresol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) dissolved in diethylene glycol dimethyl ether (DMDG) to a concentration of 60% by weight. 46.67 parts by weight of oligomer (molecular weight: 4000), 80 parts by weight of bisphenol A type epoxy resin (trade name: Epicoat 1001 manufactured by Yuka Shell Co., Ltd.) dissolved in methyl ethyl ketone, 15 parts by weight, imidazole curing agent (Shikoku Kasei Co., Ltd.) Manufactured, product name: 2E4MZ-CN) 1.6 parts by weight, polyfunctional acrylic monomer (manufactured by Nippon Kayaku Co., Ltd., product name: R604) as a photosensitive monomer, polyvalent acrylic monomer (manufactured by Kyoei Chemical Co., Ltd.) , Trade name: DPE6A) 1.5 parts by weight, dispersion antifoaming agent (manufactured by Sannopco, trade name: S-65) 0.71 layer An amount part is placed in a container, and a mixed composition is prepared by stirring and mixing. 2.0 parts by weight of benzophenone (manufactured by Kanto Chemical Co., Inc.) as a photopolymerization initiator and Michler's ketone as a photosensitizer are mixed with this mixed composition. (Kanto Chemical Co., Ltd.) 0.2 parts by weight was added to obtain a solder resist composition (organic resin insulating material) having a viscosity adjusted to 2.0 Pa · s at 25 ° C.
Viscosity measurement was performed using a B-type viscometer (DVL-B type, manufactured by Tokyo Keiki Co., Ltd.). In the case of 4 or 6 rpm, the rotor No. 3 according.
[0056]
(15) Next, the solder resist composition is applied to both surfaces of the multilayer wiring board in a thickness of 20 μm, and after drying at 70 ° C. for 20 minutes and at 70 ° C. for 30 minutes, the solder resist is applied. A photomask having a thickness of 5 mm on which an opening pattern was drawn was brought into close contact with the solder resist layer, exposed to 1000 mJ / cm ² of ultraviolet light, and developed with a DMTG solution to form an opening having a diameter of 200 μm.
Further, the solder resist layer was cured by heating at 80 ° C. for 1 hour, 100 ° C. for 1 hour, 120 ° C. for 1 hour, and 150 ° C. for 3 hours to open the solder pad portion. A solder resist layer (organic resin insulating layer) 14 having a thickness of 20 μm was formed.
[0057]
(16) Next, the substrate on which the solder resist layer (organic resin insulating layer) 14 was formed was made of nickel chloride (2.3 × 10 ⁻¹ mol / l), sodium hypophosphite (2.8 × 10 ^−1). mol / l) and sodium citrate (1.6 × 10 ⁻¹ mol / l) in a pH = 4.5 electroless nickel plating solution for 20 minutes and a nickel plating layer having a thickness of 5 μm in the opening. 15 was formed. Furthermore, the substrate gold potassium cyanide ^{(7.6 × 10 -3 mol / l} ), ammonium chloride ^{(1.9 × 10 -1 mol / l} ), sodium citrate (1.2 × 10 ^-1 mol / l) Immerse in an electroless plating solution containing sodium hypophosphite (1.7 × 10 ⁻¹ mol / l) at 80 ° C. for 7.5 minutes to form a thickness of 0 on the nickel plating layer 15. A 0.03 μm gold plating layer 16 was formed.
[0058]
(17) Thereafter, a solder paste is printed on the opening of the solder resist layer 14 and reflowed at 200 ° C. to form solder bumps (solder bodies) 17, thereby producing a multilayer wiring printed board having the solder bumps 17. (See FIG. 5 (c)).
[0059]
The obtained multilayer printed wiring board was measured for dielectric constant, dielectric loss tangent and peel strength, and subjected to a heat treatment test at 128 ° C. for 48 hours and a heat cycle test of 1000 times at −55 ° C. to 125 ° C. After the heat treatment test and after the heat cycle test, the interlayer resin insulation layer and the lower conductor circuit were peeled off and the resistance change rate of the via hole portion was measured. The results are shown in Table 1 below.
[0060]
(Example 2)
A multilayer printed wiring board is manufactured in the same manner as in Example 1 except that the conductor circuit is not etched in the step (5) and the roughening treatment is not performed on the interlayer resin insulating layer in the step (8). did. And about the obtained multilayer printed wiring board, the test and evaluation similar to Example 1 were done. The results are shown in Table 1 below.
[0061]
(Comparative Example 1)
A multilayer printed wiring board is manufactured in the same manner as in Example 1 except that a thermosetting linear polyolefin resin (manufactured by Sumitomo 3M, trade name: 1592) is used as the resin for forming the interlayer resin insulation layer. did. And about the obtained multilayer printed wiring board, the test and evaluation similar to Example 1 were done. The results are shown in Table 1 below.
[0062]
[Table 1]

[0063]
As is clear from the results of Table 1 above, the multilayer printed wiring board of the example has a small resistance change rate between the conductor circuit and the via hole even after the heating test and the heat cycle test. While peeling from the interlayer resin insulating layer was not observed, the multilayer printed wiring board of the comparative example had a large resistance change rate, or peeling occurred after the test.
[0064]
【The invention's effect】
As described above, the multilayer printed wiring board of the present invention uses a cycloolefin resin as an interlayer resin insulation layer, so that the dielectric constant and dielectric loss tangent are small, and therefore when a high frequency signal in the GHz band is used. In addition, signal delays and signal errors are unlikely to occur, and since mechanical properties such as rigidity are excellent, the reliability of the connection between conductor circuits is high, and the adhesion between the conductor circuits and the interlayer resin insulation layer is also good. Excellent.
[0065]
In addition, the method for producing a multilayer printed wiring board of the present invention forms an interlayer resin insulation layer by laminating a cycloolefin resin sheet on a conductor circuit, so that it is not necessary to use a solvent and the production process is simplified. Thus, a multilayer printed wiring board can be easily manufactured.
[Brief description of the drawings]
FIGS. 1A to 1D are longitudinal sectional views showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention.
FIGS. 2A to 2D are longitudinal sectional views showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention.
FIGS. 3A to 3D are longitudinal sectional views showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention. FIGS.
FIGS. 4A to 4C are longitudinal sectional views showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention. FIGS.
FIGS. 5A to 5C are longitudinal sectional views showing a part of the manufacturing process of the multilayer printed wiring board of the present invention. FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 2 Interlayer resin insulation layer 3 Plating resist 4 Lower layer conductor circuit 4a Roughened surface 5 Upper layer conductor circuit 6 Via hole opening 7 Via hole 8 Copper foil 9 Through hole 9a Roughened surface 10 Resin filler 12 Ni-Cu alloy layer 13 Electroplating film 14 Solder resist layer 15 Nickel plating film 16 Gold plating film 17 Solder bump

Claims (1)

In the method for manufacturing a multilayer printed wiring board in which a conductor circuit and a resin insulating layer are sequentially formed on a substrate, and these conductor circuits are connected via via holes,
On the conductor circuit formed on both sides of the substrate,
An interlayer resin insulation layer forming step of forming an interlayer resin insulation layer by vacuum compression laminating a film comprising a cycloolefin resin ;
By irradiating the interlayer resin insulating layer with an excimer laser beam through a mask having a plurality of through holes formed in a portion corresponding to the opening for via holes, the interlayer resin insulating layer is formed with a plurality of via holes at a time. Via hole forming step for forming a hole ;
A roughening treatment step of roughening the surface of the interlayer resin insulation layer having openings for the via holes;
An intermediate layer forming step of forming an intermediate layer made of Ni, Ti, Pd or Ni-Cu alloy on the roughened interlayer resin insulation layer;
Forming a via hole in the opening for the via hole in the interlayer resin insulation layer via the intermediate layer and forming a conductor circuit on the interlayer resin insulation layer via the intermediate layer ; Is performed at least once. A method for producing a multilayer printed wiring board.

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