JPH05267806A - Manufacture of base material for wiring board and multilayer printed wiring board using the same - Google Patents

Abstract

PURPOSE:To obtain sufficient bonding strength without losing electrical insulation characteristic and breakdown of impregnated resin. CONSTITUTION:A base material 1 for printed wiring board is impregnated with an epoxy resin mixing a first hardening agent which gives resistance characteristic for etching and plating and a second hardening agent which gives low compression characteristic. In this case, the epoxy resin enters the B stage. As the first hardening agent, 1.8 diazobicycro[5. 4. 0] undecene (hereinafter referred to as DBU) is used and as the second hardening agent, those obtained by adduct mixing of aromatic amine are used. Thereby, DBU shows the hardening reaction at the temperature of 85[ deg.C] and the epoxy resin enters the C1 stage, ensuring resistance characteristic for etching and plating. Moreover, aromatic amine shows the hardening reaction at 150 to 180 [ deg.C]. Accordingly, the epoxy resin enters the C2 stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board substrate and a method for producing a multilayer printed wiring board using the same.

[0002]

2. Description of the Related Art Conventionally, as a substrate for a wiring board, glass fiber, aramid fiber or polyester fiber is impregnated with thermosetting resin (epoxy, polyester, aramide, acrylic, polyacetate, polyphenylene or sulfide). A plate-shaped or film-shaped material is used.

A multilayer printed wiring board is one in which a predetermined conductor pattern is formed on a base material and a plurality of them are laminated and integrated. When the conductor pattern is formed on the base material, the strength of the base material is obtained by setting the impregnating resin in the C stage (completely cured state), while the impregnating resin is set to the C stage. Since the adhesive strength to the laminated base material becomes extremely weak, it is indispensable to interpose a prepreg impregnated with a B stage (semi-cured state) resin between the laminated base material and the laminated base material during lamination. Was becoming.

Further, the adhesive strength between the base material in which the impregnating resin is in the C stage state and the conductor pattern on the surface of the base material to be laminated is very weak. Treatment or soft etching (hydrogen peroxide + sulfuric acid)
Thus, the adhesive strength was obtained by roughening the surface of the substrate. Although such a method has an effect on the adhesive strength at room temperature, the glass transition temperature Tg (120 [° C], 15
At 0 [° C.], the temperature decreases to 1/3 to 1/10 of the normal temperature.

Therefore, in order to obtain a desired adhesive strength between the base materials, the resin impregnated in the base materials is kept in the B stage state at the bonding stage of the base materials, or At the bonding stage, the impregnating resin is put in the C stage state, and the C
Roughening the surface of the resin of the stage is being studied.

[0006]

However, in the conventional wiring board substrate, the impregnating resin is in the B stage state in order to keep the resin in the B stage state at the bonding stage between the substrate members. A conductor pattern must be formed on the base material. In this case, etching for forming the conductor pattern (using an etching solution containing ferric chloride or cupric chloride as a main component), electroplating (Reduction method such as copper sulfate plating solution or copper cyanide plating solution) or reduction method such as chemical plating of Rochelle salt copper (using formalin, sodium ethylenediaminetetraacetate, etc.). There was a problem that it deteriorates and loses its stability as an electrical insulating material, and when it is extremely severe, it melts and loses its original form.

Conventionally, as a method for roughening the surface of the resin of the C stage, soft etching (hydrogen peroxide /
Sulfuric acid, chromic acid / sulfuric acid; etching solution), laser, plasma etching or plasma sputtering, but roughening by soft etching tends to lose the property of resin as an electrical insulating material, and laser, plasma etching or plasma sputtering. The surface roughening by the method has a problem of causing local carbonization and resin destruction.

In view of the above-mentioned problems, an object of the present invention is to use a wiring board substrate capable of obtaining a sufficient adhesive strength without causing a loss or breakage of the electric insulation of the impregnated resin and using the same. A method for manufacturing a multilayer printed wiring board is provided.

[0009]

A wiring board substrate according to claim 1 provides an etching resistance and a plating resistance.
An insulating resin containing a curing agent and a second curing agent having a low shrinkage is impregnated. The wiring board substrate according to claim 2 is the wiring board substrate according to claim 1, wherein the first curing agent is 1.8 diazobicyclo [5.4.0] undecene and the second curing agent is It is characterized by being an aromatic amine.

The wiring board substrate according to claim 3 is the substrate according to claim 2.
The base material for a wiring board described above is additionally compounded with an acid anhydride or dicyandiamide. The method for manufacturing a multilayer printed wiring board according to claim 4 is as follows. A base material impregnated with an insulating resin containing a first curing agent that imparts etching resistance and plating resistance and a second curing agent that has low shrinkage is prepared. The insulating resin is cured by the curing reaction of the first curing agent. The surface of the base material on which the insulating resin has been cured by the curing reaction of the first curing agent is roughened by the reverse sputtering method. A predetermined conductor pattern is formed on the roughened base material. A predetermined laminated substrate is prepared. The base material and the base material to be laminated are arranged at predetermined positions, heated and pressed, and the insulating resin is cured by the curing reaction of the second curing agent.

[0011]

According to the structure of the present invention, the wiring board base material is impregnated with an insulating resin containing a first curing agent that imparts etching resistance and plating resistance and a second curing agent that has low shrinkage. It was made. Therefore, when the insulating resin is cured from the B stage to the C ₁ stage by the curing reaction of the first curing agent to obtain the etching resistance and the plating resistance, a predetermined conductor pattern is formed. It is possible to prevent the impregnated resin from being damaged and the electric insulation from being lost due to the etching and plating.

Further, a conductor pattern is formed and impregnated resin is
C₁Heating of the base material that is the stage and the specified base material
Pressurization causes the second curing agent to undergo a curing reaction, and the insulating resin
To C ₁From stage to C₂By curing on stage
And insert the B stage prepreg as in the past.
And good interlayer adhesion can be achieved. Also,
The surface of the substrate can be roughened by the reverse sputtering method.
Protects the impregnated resin from loss and destruction of electrical insulation.
You can

[0013]

FIG. 1 is a schematic view showing the structure of a wiring board substrate according to an embodiment of the present invention. Wiring board base material 1 shown in FIG.
Is an insulating resin in which a first curing agent that imparts etching resistance and plating resistance and a second curing agent that has a low shrinkage property are mixed with a base material made of aramid nonwoven fabric or glass woven fabric having a thickness of 0.2 [mm]. It is impregnated with an epoxy resin. At this time, the epoxy resin is in the B stage (semi-cured state).

As the first curing agent, 1 to 3% by weight of 1.8 diazobicyclo [5.4.0] undecene (hereinafter referred to as "DB
U ”. ) Is used. This DBU has a temperature of 85 [°
C] causes a curing reaction, whereby the epoxy resin is in the C ₁ stage (a state where the final hardness is not reached but etching resistance and plating resistance are obtained), and etching resistance and plating resistance can be obtained. ..

As the second curing agent, a mixture of 55-60% by weight of aromatic amine adduct is used. This aromatic amine does not cause a curing reaction at 100 [° C.] or lower, and has a temperature of 150 [° C.] to 1 [deg.] C.
A curing reaction occurs at 80 ° C., whereby the epoxy resin is in the C ₂ stage (final cured state). In addition,
As the second curing agent, an acid anhydride or dicyandiamide may be additionally blended with the aromatic amine, if necessary. In this case, only aromatic amine 10
Although the effect of preventing migration is incomplete as compared with the case of 0%, it is possible to obtain plating resistance, low shrinkage and etching resistance that are somewhat inferior. In some cases, the acid anhydride or dicyandiamide is mixed with a conventional epoxy curing agent formulating device.

A method of manufacturing a multilayer printed wiring board using the wiring board base material thus configured will be described with reference to FIGS. First, as shown in FIG. 2, the wiring board substrate 1 shown in FIG. 1 is heated in a furnace at a temperature of 85 ° C. for 30 minutes. As a result, the first curing agent causes a curing reaction, and the base material 2 in which the epoxy resin, which is the impregnating resin, changes from the B stage to the C ₁ stage is obtained.

At this time, the second curing agent does not cause a curing reaction, and the curing reaction of the first curing agent is promoted,
It does not interfere. By curing the first curing agent in this way, the epoxy resin as the impregnating resin can obtain chemical resistance to the ferric chloride etching solution, the copper sulfate plating solution and the electroless copper plating solution, and By subjecting the epoxy resin to the C ₁ stage, the base material has machinability and heat resistance as compared with the B stage.

Next, as shown in FIG. 3, after punching or drilling the holes 3 in the base material 2, the surface layer 2a and the inner wall 3a of the holes 3 are formed by the reverse sputtering method.
The surface of the is roughened by forming irregularities. By forming the surface-roughened layer 4 on the surface of the base material 2 by the reverse sputtering method in this way, the adhesion with the copper-plated layer which will be a conductor pattern in a later step is improved.

By roughening the surface of the base material 2 by the reverse sputtering method as described above, the loss of electric insulation and destruction of the impregnated resin are not caused during the roughening as in the conventional case. This reverse sputtering method is performed by using a high frequency power source with an output of 1 [kW] at a temperature of 125 [° C] or higher and lower than 150 [° C] in an argon gas atmosphere for 3 minutes. The degree of vacuum before introducing argon gas is 6.5.
It was × 10 ^-7 [Torr], and the degree of vacuum after introducing the argon gas was 4.1 × 10 ^-3 [Torr].

When a glass woven cloth or an aramide woven cloth is used as the base material, the surface roughness (difference of unevenness) is 1 to 3 [μm], and therefore, the unevenness of the surface is reduced as a composite structure. You may. Next, as shown in FIG. 4, a copper plating layer 5 having a thickness of 15 [μm] is formed on the surface layer portion 2a of the roughened substrate 2 and the inner wall portion 3a of the hole 3. The copper plating layer 5 has the same thickness in the surface layer portion 2a and the inner wall portion 3a of the hole 3, and is different from panel plating on a base material (not shown) to which a copper foil is adhered. ..

The copper plating layer 5 is an ED having a temperature of 70 ° C.
It was formed by electroless plating in a TA bath (pH 12) for 3 hours. At this time, the epoxy resin with which the base material 2 is impregnated is in the C ₁ stage due to the curing of the first curing agent, and has obtained plating resistance. Will not be invited.

Next, as shown in FIG. 5, both surfaces of the base material 2 are covered with a photopolymer film, and the conductor wirings 5a and 5b are formed in the surface layer portion 2a and the holes 3a by a known photolithography technique and etching technique. As a result, the desired conductor pattern 6 is formed. At this time, due to the curing reaction of the first curing agent, the epoxy resin which is the impregnating resin in the base material 2 becomes
Since the etching resistance is obtained, there is no loss or breakage of the electric insulation of the resin as in the conventional case.

Then, as shown in FIG. 6, as shown in FIG.
Substrate 2 (impregnating resin is C₁Stage) and the manufacturing method described above
Base material 8 on which different conductor patterns 7 are formed by the same method
(The impregnating resin is C₁Stage), with holes 9a at predetermined locations
2 base materials 9 (impregnating resin is C ₁Stage) and pre
A prepreg 10 (impregnated resin is B stage) is prepared. this
The base material 8, the two base materials 9 and the prepreg 10 are base materials to be laminated.
It is a material.

Then, the base material 9 is placed on the upper surface of the base material 2 and
The base material 9 is arranged on the lower surface of the material 8 and is guided between the base material 2 and the base material 8.
Place prepreg 10 for insulation between body patterns 6 and 7
It Next, as shown in FIG. 7, the base material arranged as shown in FIG.
15k pressure against 2,8,9 and prepreg 10
g / cm²And pressurize under the condition of temperature 160 [° C]
It As a result, the curing reaction of the second curing agent occurs and the base material
2,8 impregnating resin is C ₁From stage to C₂Stage (up
Final cured state), and also the base material 9 and the prepreg 1
0 impregnating resin is C₂It will be the stage (final curing state)
Then, the layers are adhered to each other to form the multilayer body 11. Because
A prepreg between the base materials 2 and 9 and between the base materials 8 and 9.
Good adhesion can be achieved without interposing.

The thickness of the multilayer body 11 is 0.2 [mm] × 4.
It becomes +0.2 [mm]. The inner layer 11a of the multi-layer body 11 has a positional error of 0.02% or less.
(IVA; Interstitial Via hole) will be formed. Next, as shown in FIG. 8, after the surface layer portion of the multilayer body 11 and the inner wall portion of the hole are subjected to reverse sputtering (reverse sputtering treatment across both the conductor portion and the wiring portion), the surface layer portion Copper plating layer 1 on predetermined area and inner wall
Apply steps 2 and 13. Thereby, the desired multilayer printed wiring board 1
Get 4.

In the step shown in FIG. 6, a base material impregnated with a C ₁ stage resin was used as the base material placed on the upper surface of the base material 2 and the lower surface of the base material 8. When a resin-impregnated base material is used, by heating and pressing with a press in the step shown in FIG.
It is possible to obtain a flattened multilayer printed wiring board 15 by embedding 3a. By flattening the surface in this manner, it becomes possible to easily mount a surface mount electronic component (not shown).

Here, the relationship between the curing agent and the adhesive strength will be described with reference to [Table 1]. In [Table 1], the curing temperature indicates the temperature at which the impregnated resin can obtain etching resistance and plating resistance, Tg indicates the glass transition temperature, and the copper foil adhesive strength is the thickness of 35 [μm] formed on the substrate.
Shows the adhesive strength of the copper foil, the plating adhesive strength A shows the plating adhesive strength when plating is formed without roughening the surface of the base material, and the plating adhesive strength B shows the reverse surface of the base material. The plating adhesion strength when the surface is roughened by a sputtering method to form a plating is shown.

In Example 1, a resin containing DBU, aromatic amine and dicyandiamide as a curing agent (the compounding ratio of aromatic amine and dicyandiamide was 97: 3 to 99: 1) was impregnated. Example 2 is a multilayer printed wiring board formed by using a base material impregnated with a resin containing DBU and an aromatic amine as a curing agent, and Comparative Example 1 is a comparative example 1. A multilayer printed wiring board formed by using a base material impregnated with a resin mixed with only dicyandaiamide as a curing agent, Comparative Example 2 is a base material impregnated with a resin mixed with only an aromatic amine as a curing agent. It is a multilayer printed wiring board formed by using.

[0029]

[Table 1]

As is clear from Table 1, in comparison with Comparative Example 1 and Comparative Example 2, Example 1 and Example 2
It can be seen that high adhesive strength is obtained between the base materials, the copper foil, and the plating layer. Further, by blending DBU and aromatic amine, a glass transition temperature Tg of 150 [° C.] or higher is obtained. The glass transition temperature Tg is 1 to the compounding amount of DBU with respect to the epoxy resin.
+10 [° C] to -30 [° C] by changing the amount of 4.8% by weight, the amount of dicyanamide to 0.5 to 2.5% by weight, and the amount of aromatic amine to 45 to 60% by weight. ] It can be changed in the range.

As described above, according to the embodiment, the base material 1 is obtained by impregnating the base material with an epoxy resin containing a first curing agent that imparts etching resistance and plating resistance and a second curing agent having low shrinkage. Is. After the epoxy resin is changed from the B stage to the C ₁ stage by the curing reaction of the first curing agent to form the base material 2 having the etching resistance and the plating resistance, the predetermined conductor pattern 6 is formed on the base material 2. .. As a result, it is possible to prevent the impregnated resin from being destroyed and the electrical insulation from being lost due to etching and plating when the conductor pattern 6 is formed.

By heating and pressurizing the base materials 2 and 8 on which the conductor pattern 6 is formed and the impregnated resin is the C ₁ stage and a predetermined base material 9 to be laminated, a curing reaction occurs in the second curing agent, By changing the impregnating resin from the C ₁ stage to the C ₂ stage, good interlayer adhesion can be achieved without inserting the B stage prepreg as in the conventional case.

Further, by roughening the surface of the substrate by the reverse sputtering method, it is possible to prevent the impregnating resin from losing or breaking its electrical insulation. As a result, it is possible to obtain sufficient adhesive strength without causing loss and breakage of the electric insulation of the impregnated resin. In the example,
The copper plating layer 5 shown in FIG. 4 is formed by electroless plating, but a copper sulfate bath (pH 9) at a temperature of 65 ° C. is used.
10 to 10) may be formed by electroplating under the condition of 3 to 5 minutes. In this case, a copper plating layer having a thickness of 13 to 14 [μm] can be formed, and the treatment bath temperature does not cause deterioration of the substrate itself. Furthermore, after forming a copper plating layer of several [μm] by electroless plating, the copper plating layer may be formed by electroplating. As a result, the panel plating formation time can be shortened.

[0034]

EFFECTS OF THE INVENTION According to the wiring board substrate of the present invention and the method for manufacturing a multilayer printed wiring board using the same, the wiring board substrate causes a curing reaction at the first temperature on the substrate to cause etching resistance. And a low-shrinking second curing agent that causes a curing reaction at a second temperature higher than the first temperature and is impregnated with an insulating resin.

Therefore, after the insulating resin is cured from the B stage to the C ₁ stage by the curing reaction of the first curing agent to obtain the etching resistance and the plating resistance, a predetermined conductor pattern is formed to form the conductor. It is possible to prevent destruction of the impregnated resin and loss of electrical insulation due to etching and plating during pattern formation.

Further, the conductor pattern is formed and the impregnated resin is
C₁Heating of the base material that is the stage and the specified base material
Pressurization causes the curing reaction of the second curing agent, causing an insulating resin
To C ₁From stage to C₂By curing on stage
Then, insert the B stage prepreg as in the past.
It is possible to perform good interlayer adhesion without causing any trouble. Well
In addition, the surface of the substrate is roughened by the reverse sputtering method.
Protects the impregnated resin from loss of electrical insulation and destruction.
You can stop.

As a result, sufficient adhesive strength can be obtained without causing loss or breakage of the electric insulation of the impregnated resin.

[Brief description of drawings]

FIG. 1 is a schematic view showing the structure of a wiring board substrate according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a first step of a method for manufacturing a multilayer printed wiring board using a wiring board base material according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a second step of the method for manufacturing a multilayer printed wiring board using the same wiring board base material.

FIG. 4 is a cross-sectional view showing a third step of the method for manufacturing a multilayer printed wiring board using the same wiring board base material.

FIG. 5 is a cross-sectional view showing a fourth step of the method for manufacturing a multilayer printed wiring board using the same wiring board base material.

FIG. 6 is a cross-sectional view showing a fifth step of the method for manufacturing a multilayer printed wiring board using the same wiring board base material.

FIG. 7 is a cross-sectional view showing a sixth step of the method for manufacturing a multilayer printed wiring board using the same wiring board base material.

FIG. 8 is a cross-sectional view showing a seventh step of the method for manufacturing a multilayer printed wiring board using the same wiring board base material.

FIG. 9 is a cross-sectional view showing a multilayer printed wiring board whose surface is flattened.

[Explanation of symbols]

 1 Base material for wiring board 6 Conductor pattern

Claims (4)

[Claims] 1. A substrate for a wiring board impregnated with an insulating resin containing a first curing agent that imparts etching resistance and plating resistance and a second curing agent that has low shrinkage. 2. The wiring board group according to claim 1, wherein the first curing agent is 1.8 diazobicyclo [5.4.0] undecene and the second curing agent is aromatic amine. Material. 3. The wiring board substrate according to claim 2, further comprising an acid anhydride or dicyandiamide. 4. A step of preparing a base material impregnated with an insulating resin containing a first curing agent that imparts etching resistance and plating resistance and a second curing agent having low shrinkage, and curing of the first curing agent. A step of curing the insulating resin by a reaction, a step of roughening the surface of the base material on which the insulating resin has been cured by the curing reaction of the first curing agent by a reverse sputtering method, and the roughening A step of forming a predetermined conductor pattern on the base material; a step of preparing a predetermined base material to be laminated; and placing the base material and the base material to be laminated at predetermined positions and heating and pressurizing the second curing agent. And a step of curing the insulating resin by a curing reaction of 1.