JP2001151837A - Insulating resin composition and method of manufacturing multilayer printed circuit board by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a insulating resin composition having high insulation reliability, excellent in sustainability of adhesive strength to plated copper at a high temperature and humidity, and to provide a method of manufacturing a multilayer printed circuit board by using the same. SOLUTION: This insulating resin composition comprises an epoxy resin which is modified with an acid anhydride and a heat-curing agent which generates a Lewis acid when heated. The method of manufacturing the multilayer printed circuit board comprises forming an insulating layer on an internal layer circuit board equipped with an internal layer circuit by using the insulating resin composition, laminating a photomask for masking an area excluding spots which will become via holes, exposing to light, and removing the unexposed resin composition on the spots with a developing solution to form the multilayer printed circuit board.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an insulating material composition and a method for producing a multilayer wiring board.

[0002]

2. Description of the Related Art A general multilayer wiring board is formed by impregnating a glass cloth called a prepreg with an epoxy resin on an insulating substrate on which an inner layer circuit is formed, laminating a semi-cured material with a copper foil and laminating by hot pressing. After integration, a hole called a through hole for interlayer connection is drilled, electroless plating is performed on the inner wall of the through hole and the copper foil surface, and if necessary, electrolytic plating is further performed to achieve the required thickness as a circuit conductor. After that, unnecessary copper is removed to manufacture a multilayer wiring board. By the way, in recent years, the miniaturization, weight reduction, and multifunctionality of electronic devices have been further advanced, and with this, the integration of LSIs and chip components has been advanced, and the form has rapidly changed to multipins and miniaturization. ing. For this reason, in order to improve the mounting density of electronic components, development of fine wiring has been promoted for multilayer wiring boards. However, there is a technical limit in reducing the wiring width, and the wiring width that can be mass-produced at present is 75 to 100 μm. For this reason, it is difficult to achieve a significant increase in the wiring density simply by reducing the wiring width. A bottleneck for improving the wiring density is a through hole occupying an area of about 300 μm in diameter. Since the through holes are generally formed by a mechanical drill, the dimensions thereof are relatively large, so that the degree of freedom in wiring design is reduced. In order to solve these problems, a method is known in which an insulating resin having photosensitivity is formed on an insulating substrate on which a circuit is formed, and fine via holes are formed in the insulating resin by a photo process to perform interlayer connection. -55555 and JP-A-63-126
No. 296.

[0003]

As described above, the multilayer wiring board connected between layers by the fine via holes formed by the photo process greatly contributes to the problem of improving the wiring density of the conventional multilayer wiring board. It is.
The insulating material used in this photo process requires a photolithography function, a plating material function, and an insulating function. Therefore, it is an absolute condition that many functions are added to the insulating material in a well-balanced manner. In general, in order to have both the photolithographic function and the plating material and the insulating function, a material having a photofunctional group, a thermosetting material, and a thermosetting agent for curing the thermosetting material by heating are required. However, it is extremely difficult to cure a material having a photofunctional group and a thermosetting material in a network. The reason for this is that in order to exhibit the photolithographic function, a composition system mainly comprising a material having a photofunctional group must be used. Most of the materials having photofunctional groups cause a photoreaction in the exposure and development processes for forming via holes, but the photoreaction has already occurred in the heat-curing process. This is because curing hardly proceeds. For this reason, the curing of the insulating material layer is likely to be hardened due to poor thermal stability mainly due to photoreaction, and as a result, high insulation reliability and adhesive strength under high temperature and high humidity are likely to be hindered. Was.

The present invention has high insulation reliability,
An object of the present invention is to provide an insulating resin composition for a multilayer wiring board excellent in maintaining adhesive strength to plated copper under high humidity and a method for manufacturing a multilayer wiring board using the same.

[0005]

The present invention is characterized by the following. (1) An insulating resin composition comprising an epoxy resin modified with an acid anhydride compound and a thermosetting agent that generates a Lewis acid upon heating. (2) On the inner circuit board on which the inner circuit is formed, an insulating layer is formed with the insulating resin composition described in (1), and a photomask for masking a portion other than a portion serving as a via hole is overlaid. A method for manufacturing a multilayer wiring board, comprising a step of irradiating and exposing unexposed portions with a developer.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin modified with an acid anhydride used in the present invention is obtained by modifying the epoxy group of the epoxy resin with maleic anhydride, tetrahydrophthalic anhydride, itaconic anhydride, hexahydrophthalic anhydride, Succinic anhydride, naphthalic anhydride, citraconic anhydride, carboxylic anhydride, methylphthalic anhydride, dichlorophthalic anhydride, chlorendic anhydride, butenyltetrahydrophthalic anhydride, methyltetrahydrophthalic acid Compounds modified with anhydrides, alkenyl anhydrides, tricarballylic anhydrides and the like can be mentioned.

The epoxy resin modified with an acid anhydride is not particularly limited, and includes bisphenol A type, phenol novolak type, ortho-cresol novolak type, Br
Epoxy resin, bisphenol F type, bisphenol S type, salicylaldehyde type and the like. Any thermosetting agent that generates a Lewis acid by heating can be used as long as it is a cationic reaction type latent thermosetting agent. For example, triphenylsulfone hexafluoroantimonate, triphenylsulfone hexafluorophosphate, P-methoxybenzenediazonium hexafluorophosphate, P-chlorobenzenediazonium hexafluorophosphate, diphenyliodonium hexafluorophosphate, 4,4-
Di-t-butylphenyliodonium hexafluorophosphate, (1-6-n-cumene) (n-dichloropentadienyl) iron hexafluorophosphate can be used.

The amount of the thermosetting agent that generates a Lewis acid upon heating is determined by the amount of epoxy resin 100 modified with an acid anhydride.
It is used in the range of 0.5 to 15 parts by weight with respect to parts by weight. More preferably, it is in the range of 1.0 to 10 parts by weight. If the blending amount of the thermosetting agent that generates a Lewis acid is less than 0.5 parts by weight based on 100 parts by weight of the epoxy resin modified with the acid anhydride, the epoxy resin modified with the acid anhydride is hardly cured, and the high temperature and high temperature The insulation reliability under humidity and the adhesive strength between the insulating layer and the plated copper are reduced. If the amount is more than 15 parts by weight, there is a Lewis acid which does not contribute to the reaction, and the adverse effect of increasing the corrosion of the circuit conductor occurs. As described above, the epoxy resin modified with an acid anhydride and the thermosetting agent which generates a Lewis acid upon heating are essential components. In addition, butadiene acrylonitrile rubber, natural rubber, SBR, carboxylic acid modified butadiene acrylonitrile rubber, carboxylic acid modified It is preferable to add acrylic rubber, crosslinked NBR particles, and carboxylic acid-modified crosslinked NBR particles in terms of improving flexibility.

[0009] A filler can also be blended.
As filler, silica, fused silica, talc, alumina, hydrated alumina, barium sulfate, calcium hydroxide,
Examples include inorganic fine particles such as aerosil and calcium carbonate, organic fine particles such as a powdery epoxy resin and powdery polyimide particles, and powdery Teflon particles. These fillers may be subjected to a coupling treatment. These dispersions can be achieved by a known kneading method such as a kneader, a ball mill, a bead mill, and a three-roll mill.

As the photopolymerization initiator used in the present invention, commercially available products can be used, and there is no particular limitation. Furthermore, in order to impart heat resistance to the insulating layer, a thermosetting resin such as an epoxy resin, an acrylate-modified epoxy resin, a melamine resin, and a cyanate ester resin is used in combination with the composition within a range that does not adversely affect exposure and development in a photo process. Is also preferred.

Next, with reference to FIG. 1, a process for manufacturing a multilayer wiring board using the insulating material composition of the present invention will be described by way of example. First, the first circuit layer (1a) is formed on the insulating substrate 2.
Is prepared (see FIG. 1A). The insulating substrate 2 is a known laminated board used in a normal wiring board, for example, glass cloth-epoxy resin, paper-phenol resin, paper-epoxy resin, glass cloth / glass paper-
An epoxy resin or the like can be used, and there is no particular limitation. There is no particular limitation on the method for forming the circuit layer 1a, and a subtractive method in which an unnecessary portion of the copper foil is removed by etching using a copper-clad laminate in which a copper foil and the insulating substrate are bonded, A known method of manufacturing a wiring board, such as an additive method of forming a circuit by electroless plating on a required portion of an insulating substrate, can be used. FIG. 1A shows an example in which a circuit layer 1a is formed on one surface of an insulating substrate 2, but the circuit layer 1a is formed by using a double-sided copper-clad laminate.
Can also be formed on both sides. Next, the surface of the circuit layer 1a is surface-treated to a state suitable for adhesiveness. This technique, too,
There is no particular limitation. For example, copper oxide needle-like crystals are formed on the surface of the circuit layer 1a with an aqueous solution of sodium hypochlorite, and the formed copper oxide needle-like crystals are immersed in a dimethylamine borane aqueous solution for reduction. For example, a known manufacturing method can be used.

Next, an insulating material composition layer 4b is formed on the surface of the circuit layer 1a (see FIG. 1B). Insulating material 4b
Can be formed by a method in which a liquid resin is applied by a method such as roll coating, curtain coating, or dip coating, or a method in which the insulating resin is formed into a film and laminated by lamination. The thickness of the insulating material composition layer 4b is not particularly limited, and is usually 20 to 150 μm.
Is appropriately selected within the range.

Next, a light beam 6 is applied to the insulating material composition layer 4b through a photomask 5c formed so as to mask a place where a via hole 7d to be connected to the circuit layer 1a is to be formed.
Exposure to irradiate c (usually, ultraviolet light is used as a light source and the same method as that for forming a resist on a normal wiring board is used) is performed (see FIG. 1C).

Next, the unexposed portion of the insulating material composition layer 4b is developed by a method of etching with a developer to form a via hole 7d (see FIG. 1D). The method of etching with a developer can be a known method and is not particularly limited. For example, spraying a developer or dipping in a developer may be mentioned. The developing solution to be used is determined by what kind of developing type the insulating resin composition is, but a general developing solution such as an alkali developing solution, a semi-aqueous developing solution, and a solvent developing solution can be used. After development, post-exposure is performed if necessary. Then, post-heating is performed. Thereafter, the heating is important for exhibiting the effects of the present invention, and the temperature is in the range of 130 ° C. to 200 ° C. for 30 minutes to 120 minutes. In addition, the range in which the insulating material composition layer 4b is most efficiently cured under the condition that the substrate does not hinder the post-process due to thermal deterioration is good, and the preferable post-heating range is 130 to 18.
45 minutes to 90 minutes at a temperature of 0 ° C. The insulating layer that has been subjected to post-curing by heating is used as the insulating layer 8d.

Next, the surface of the insulating layer 8d and the inside of the via hole are treated with an oxidizing roughening solution. As the oxidizing roughening liquid,
A chromium / sulfuric acid roughening solution, an alkali permanganic acid roughening solution, a sodium fluoride / chromium / sulfuric acid roughening solution, a borofluoric acid roughening solution, and the like can be used. Next, it is immersed in an aqueous solution of stannous chloride in hydrochloric acid to perform a neutralization treatment, and further, a plating catalyst application treatment for attaching palladium is performed. The plating catalyst treatment is performed by dipping in a palladium chloride-based plating catalyst solution. Next, by immersing in an electroless plating solution, an electroless plating layer having a thickness of 0.3 to 1.5 μm is deposited thereon. If necessary, electroplating is further performed. As the electroless plating solution used for the electroless plating, a known electroless plating solution can be used, and there is no particular limitation. Also, the electroplating can be performed by a known method, and there is no particular limitation. Next, by performing the circuit processing thus formed, the circuit layer 1e and the interlayer connection between the circuit layer 1a and the circuit layer 1e are formed (see FIG. 1E).

As a method for forming the circuit layer 1e, a catalyst for electroless plating is applied to the surface of the roughened insulating layer to deposit electroless plated copper on the entire surface. Make the circuit conductor the required thickness by plating,
A method in which unnecessary portions are removed by etching, a method in which a plating resist is formed using an insulating layer containing a plating catalyst, and a circuit is formed by electroless plating only in necessary portions, and an insulating method in which a plating catalyst is not contained. After roughening the layer and applying a plating catalyst, a plating resist is formed, and a circuit is formed by electroless plating only at a necessary portion. Thereafter, the surface treatment of the circuit layer 1e is performed in the same manner as the surface treatment of the circuit layer 1a, and thereafter, the insulating material composition layer 4f is formed in the same manner as the formation of the layer 1e (see FIG. 1 (f)). Light rays 6 pass through 5g to insulating material 4f.
g is exposed (see FIG. 1 (g)), and the unexposed portion of the insulating material 4f is developed by etching in a developer to form a via hole 7h, and the insulating material 4f is cured by insulating. The layer 8h is formed (see FIG. 1H), and the circuit layer 1i is formed (see FIG. 1I). Hereinafter, by repeating the same steps, a multilayer wiring board having a large number of layers can be manufactured.

[0017]

Example 1 (1) MC which is a double-sided copper-clad laminate made of a glass cloth base epoxy resin having a double-sided roughened foil having a copper foil thickness of 18 μm on both sides.
LE-67 (trade name, manufactured by Hitachi Chemical Co., Ltd.) was subjected to etching to produce a circuit board having a circuit layer (hereinafter, referred to as a first circuit layer) on one surface. (2) An insulating resin having the following composition was applied on a PET film and dried at 80 ° C. for 20 minutes to produce a film with an insulating resin. This film with an insulating resin was formed on one surface of the circuit board on the side where the insulating resin was in contact with the circuit layer using a laminator to form an insulating layer having a thickness of 50 μm. -Tetrahydroxyphthalic anhydride-modified epoxy resin: PCR-1050 (Nippon Kayaku Co., Ltd., trade name) ... 50 parts by weight-Acrylate-modified epoxy resin: YDV-1011 (Toto Kasei Co., Ltd., trade name) ... 20 weight parts Part: Carboxylic acid-modified butadiene: Hiker CTBN1300 × 13 (manufactured by Ube Industries, Ltd., trade name) 10 parts by weight ・ Carboxylic acid-modified acrylonitrile butadiene rubber: XER-31SK-25 (manufactured by JSR Corporation, trade name) ... 8 parts by weight -Photoinitiator: Irgagua 651 (Ciba Geigy Co., Ltd., trade name) ... 5 parts by weight-Filler, aluminum hydroxide: Heidilite H-42M (Showa Denko Co., Ltd., trade name) ... 10 parts by weight-Thermal Lewis Acid generator: SI-100L (trade name, manufactured by Sanshin Chemical Co., Ltd.) 2 parts by weight (3) A 30 mJ / cm ² ultraviolet ray is irradiated through a photomask in which a shielding portion is formed in a portion to be a hole, and the unexposed portion is further exposed to 10 vol% of 2-2 butoxyethoxy ethanol and 8 g of sodium borate.
Spray treatment was carried out at 30 ° C. for 1 minute with a developing solution containing / l to form via holes. (4) Using a metal halide lamp-type conveyor-type exposure machine (lamp output: 80 W / cm ² , lamp height: 80 cm, no cold mirror, conveyor speed: 1.5 m / min), and insulates ultraviolet light at 1000 mJ / cm ^2. To perform post-exposure. (5) After heating at 150 ° C. for one hour, an insulating layer having via holes was formed. (6) In order to chemically roughen the insulating layer, K
An aqueous solution of MnO ₄ : 60 g / l and NaOH: 40 g / l is prepared, heated to 70 ° C. and immersed for 5 minutes. Subsequently, a neutralization solution (SnCl ₂ : 30 g / l, HCl: 30
(0 ml / l) aqueous solution at room temperature for 5 minutes for neutralization. (7) In order to form a second circuit on the surface of the first insulating layer, first, H, an electroless plating catalyst containing PdCl ₂ , is used.
S-202B (manufactured by Hitachi Chemical Co., Ltd., trade name)
Immersion treatment at room temperature for -10 minutes, washing with water, immersion in an L-59 plating solution (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is electroless copper plating, at 70 ° C. for 30 minutes, and further performing copper sulfate electrolytic plating Then, a conductor layer having a thickness of 20 μm is formed on the surface of the insulating layer. Next, an etching resist is formed to remove unnecessary portions of the plated conductor by etching, etching is performed, and then the etching resist is removed to form a second circuit including a via hole connected to the first circuit. . (8) Further, in order to form a multilayer, the surface of the second circuit conductor is made of sodium chlorite: 50 g / l, NaOH: 20
g / l, 10 g / l trisodium phosphate in aqueous solution
C. for 20 minutes, rinse with water, and dry at 80.degree. C. for 20 minutes to form copper oxide irregularities on the surface of the second circuit conductor. (9) The steps (2) to (7) were repeated to produce a three-layer multilayer wiring board.

Example 2 Example 1 was repeated except that the thermal Lewis acid generator SI-100L was used.
(Made by Sanshin Chemical Co., Ltd., trade name) instead of CP-66
(Trade name, manufactured by Asahi Denka Kogyo Co., Ltd.). Other than that, it carried out similarly to Example 1.

Example 3 In Example 1, a bisphenol A type epoxy resin, Epicoat 1001 (oiling shell) was used in place of PCR-1050 (trade name, manufactured by Nippon Kayaku Co., Ltd.), a tetrahydroxyphthalic anhydride-modified epoxy resin. An epoxy resin was prepared by modifying maleic anhydride (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) under conditions of 130 ° C. for 20 hours. The compounding amount is the same as in Example 1,
Others were performed similarly to Example 1.

Comparative Example 1 In Example 1, SI-100L, a thermal Lewis acid generator, was used.
(Trade name, manufactured by Sanshin Chemical Co., Ltd.). The other steps were the same as in Example 1.

Comparative Example 2 In Example 3, the thermal Lewis acid generator SI-100L was used.
(Trade name, manufactured by Sanshin Chemical Co., Ltd.). The other steps were the same as in Example 1.

With respect to the multilayer wiring board manufactured as described above, the resolution of the via hole, the peel strength (the bonding strength between the insulating layer and the plated copper), and the interlayer insulation resistance were described by the following methods. Table 1 shows the results. (Resolution of Via Hole) In a process corresponding to (3) of Example 1, a photomask was formed with a diameter of 50 to 150 μm.
, A circular black circle shielding portion was provided at an interval of 10 μm to form a via hole. The minimum diameter at which the via hole could be formed was evaluated by a metallographic microscope after performing the process corresponding to Example (6). (Peel strength) L1 width on a part of L1 circuit layer (third circuit layer)
A portion having a length of 0 mm and a length of 100 mm was formed, and one end of the portion was peeled off, gripped with a gripper, and the load when the film was peeled off by about 50 mm in the vertical direction was measured. Table 1 shows normal and 121
It shows the result of measurement after holding for 48 hours in a pressure cooker tester at 100 ° C. and 100% RH (indicated as PCT-48 in Table 1). (Interlayer insulation resistance) L1-L2 was measured using a test piece cut so as not to include connection between circuit layers by via holes.
The insulation resistance between them (between the third circuit and the second circuit) was measured. Table 1 shows the results of measurements under normal conditions and after holding for 100 hours in a 110 ° C., 85% RH pressure cooker tester (indicated as PCT-100 in Table 1).

[0023]

[Table 1]

From Table 1, it is shown that the via hole resolution, which is an important characteristic in the photo process, is the same in the three-layered multilayer wiring boards of Examples 1 to 3 and Comparative Examples 1 and 2. In the three-layered multilayer wiring board according to Examples 1 to 3, 121 ° C.-100% RH or 110 ° C.-85
It was shown that the peel strength and interlayer insulation resistance did not decrease much even under high temperature and high humidity of% RH. On the other hand, in the three-layer multilayer wiring board in Comparative Examples 1 and 2, 121 ° C.
High temperature of -100% RH or 110 ° C-85% RH
The peel strength under high humidity is about 0.3 to 0.1 as compared with the embodiment.
It was shown that the degree of reduction of the interlayer insulation resistance was about 3 orders of magnitude higher than that of the example.

[0025]

As described above, according to the present invention, an insulating resin composition for a multilayer wiring board having high insulation reliability and excellent in maintaining adhesive strength with plated copper under high temperature and high humidity. An object and a method for manufacturing a multilayer wiring board using the same can be provided.

[Brief description of the drawings]

FIGS. 1A to 1I are cross-sectional views illustrating steps for manufacturing a multilayer wiring board.

[Explanation of symbols]

 1a, 1e, 1i. Circuit layer 2. 2. Insulating substrate Circuit board 4b, 4f. Insulating material composition 5c, 5g. Photomask 6c, 6g. Rays 7d, 7h. Via hole 8d, 8h. Insulating layer

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masaki Morita 1500 Oji Ogawa, Shimodate City, Ibaraki Prefecture Inside Hitachi Chemical Co., Ltd. (72) Inventor Takako Watanabe 1500 Ogawa Ogawa Shimodate City Ibaraki Prefecture F-term in Reference Laboratory (Reference) 2H096 AA26 BA20 EA02 GA08 HA01 HA03 JA04 4J027 AA08 AE01 AE02 AE03 AE04 CA08 CA10 CA14 CA16 CA18 CA26 CA27 CB10 CD06 CD10 4J036 AD08 AD20 AF06 AF08 AF36 CA19 CA20 FA03 FA04 FA05 FB03 FB03 5E346 AA05 AA06 AA12 AA43 CC09 DD02 DD22 DD32 EE31 EE38 FF04 GG15 GG17 GG22 GG27 GG28 HH11

Claims (2)

[Claims] An epoxy resin modified with an acid anhydride compound,
An insulating resin composition comprising a thermosetting agent that generates a Lewis acid upon heating. 2. An insulating layer is formed of the insulating resin composition according to claim 1 on an inner circuit board on which an inner circuit is formed, and a photomask for masking a portion other than a portion serving as a via hole is overlaid. A method for manufacturing a multilayer wiring board, comprising a step of irradiating light and removing a portion not exposed with a developing solution.