JPH09232758A - Manufacture of wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a wiring board, which can make an insulating resin fill favorably in non-penetration through holes. SOLUTION: An insulating resin 3 is applied on the surface of a wiring board 2 having non-penetration through holes 1 and at the same time, this resin 3 ia made to fill in the holes 1 to manufacture a wiring board. At the time of the manufacture of this wiring board, the inner peripheries of the holes 1 are wetted with solvent and thereafter, the resin 3 is applied on the inner peripheries to make the resin 3 fill in the holes 1 The wetting of the resin 3 to the inner peripheries of the holes 1 is enhanced by the solvent to wet the inner peripheries of the holes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer wiring board having non-penetrating through holes.

[0002]

2. Description of the Related Art As electronic devices are required to be light, thin, short and small, there is an increasing need for high density printed wiring boards. For this reason, in manufacturing a multilayer wiring board, non-through through holes have been increasingly used in place of the conventional through through holes for connecting circuits of respective layers. Since the non-penetrating through hole is not provided so as to penetrate the wiring board, the area of the wiring board can be effectively used.

As a method of manufacturing a wiring board having such a non-penetrating through hole, there is a method provided in Japanese Patent Laid-Open No. 59-175796. In this method, a plurality of substrates having circuit patterns and through holes formed in advance are stacked via a prepreg, and these are heated and pressed to form a multilayer, so that the through holes are provided in the wiring board as non-through holes. It is a thing. However, in this method, since the through holes are formed in the substrate by drilling or the like, it is not easy to reduce the diameter of the through holes, and there is a limitation in increasing the density of the non-penetrating through holes formed from the through holes.

On the other hand, as disclosed in JP-A-2-260491, an insulating resin such as a photosensitive resin is applied to the surface of the substrate to form an insulating layer, and the insulating layer is exposed / developed. The non-penetrating through-holes are formed by hardening treatment, and the insulating resin is further applied to the surface of the insulating layer to form the insulating layer. Construction methods are provided. In this method, the non-penetrating through holes can be formed by the process of exposure / development. Therefore, it is easy to reduce the diameter of the non-penetrating through holes, and it is easy to increase the density of the non-penetrating through holes.

[0005]

When a wiring board is manufactured by the build-up method as described above, a non-penetrating through-hole is formed when an insulating resin is applied on the non-penetrating through-hole to further form an insulating layer. It is necessary to fill the inside with insulating resin. If the insulating resin is not sufficiently filled in the non-penetrating through holes, voids are generated in the non-penetrating through holes, and swelling easily occurs in this portion when high temperature acts in the soldering process or the like. However, it is difficult to sufficiently fill the non-penetrating through holes with the insulating resin when the insulating resin is applied, and the occurrence of swelling has been a problem.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method of manufacturing a wiring board in which a non-penetrating through hole can be satisfactorily filled with an insulating resin.

[0007]

In the method of manufacturing a wiring board according to the present invention, an insulating resin 3 is applied to the surface of a wiring board 2 having a non-through hole 1 and the insulating resin 3 is applied to the non-through hole 1. In manufacturing a wiring board including a step of filling the non-penetrating through hole 1 with a solvent, the non-penetrating through hole 1 is filled with the insulating resin 3 after the inner periphery of the non-penetrating through hole 1 is wetted with a solvent. It is characterized by.

Further, the invention of claim 2 is characterized in that the solvent is sprayed to wet the inner periphery of the non-penetrating through hole 1 with the solvent. The invention of claim 3 is characterized in that a solvent is applied to the surface of the wiring substrate 2 by a roll coater to wet the inner circumference of the non-penetrating through hole 1 with the solvent. The invention of claim 4 is characterized in that the wiring substrate 2 is immersed in a solvent to wet the inner periphery of the non-penetrating through hole 1 with the solvent.

Further, the invention of claim 5 is characterized in that the non-penetrating through hole 1 is filled with the insulating resin 3 by applying with a squeegee. Claim 6
The present invention is characterized in that the non-penetrating through hole 1 is filled with the insulating resin 3 by coating with a bar coater. The invention of claim 7 is characterized in that a plurality of insulating resins 3 having different fluidity are applied in order from the one having good fluidity.

Further, the invention of claim 8 is characterized in that the wiring board 2 is vibrated when the non-penetrating through hole 1 is filled with the insulating resin 3.

[0011]

Embodiments of the present invention will be described below. FIG. 1 shows an example of manufacturing a wiring board by a build-up method. First, a core inner layer substrate 10 shown in FIG. A circuit 11 is formed on the core inner layer substrate 10 by printing or the like. Then, the liquid insulating resin is applied to both surfaces of the core inner layer substrate 10 by a curtain coater, screen printing or the like to form the insulating layers 12a and 12b on both surfaces of the core inner layer substrate 10, respectively. The non-penetrating through hole 1 is provided in the insulating layers 12a and 12b at the location of the required circuit 11. When the insulating resin forming the insulating layers 12a and 12b is a photosensitive resin, the non-penetrating through hole 1 can be formed by exposure and development. Insulating layer 12a,
When the insulating resin forming 12b is a thermosetting resin, the non-penetrating through hole 1 can be formed by laser processing or the like. Further, a circuit 11 is formed on the surfaces of the insulating layers 12a and 12b by a semi-additive method or a subtractive method, and a connection layer 13 for conducting the inner and outer circuits 11 is formed on the inner circumference of the non-through hole 1 by plating or the like. As a result, the wiring board 2 as shown in FIG. 1B can be manufactured.

In the present invention, the insulating resin 3 is applied to the surface of the wiring board 2 provided with the non-penetrating through holes 1 in this way, and the insulating layer 14 is further provided on the surface of the wiring board 2. In the example of FIG. 1, the insulating layer 12a on one side of the wiring board 2
The insulating resin 3 is applied only to the surface of the. In the present invention, the inner circumference of the non-penetrating through hole 1 is wetted with a solvent in advance before the insulating resin 3 is applied to the surface of the insulating layer 12a. If the inner circumference of the non-penetrating through hole 1 is wetted with the solvent in this manner, the wetting of the insulating resin 3 on the inner circumference of the non-penetrating through hole 1 is improved, and when the insulating resin 3 is applied to the surface of the insulating layer 12a. The insulating resin 3 smoothly flows into the non-penetrating through hole 1,
The non-penetrating through hole 1 can be filled with the insulating resin 3 satisfactorily. As this solvent, it is preferable to use the same kind of solvent as the solvent mixed in the insulating resin 3.

In this way, the inner periphery of the non-penetrating through hole 1 can be wetted with a solvent by spraying the solvent, coating with a roll coater, or immersing the wiring board 2 in the solvent. When the solvent is sprayed to wet the inner periphery of the non-penetrating through-hole 1, the spray can apply the solvent only to a necessary portion, so that the amount of the solvent used can be saved and it is economical. . Further, since the roll coater can apply the solvent to a large area on the surface of the wiring board 2 at a time, the roll coater can be applied to the inner circumference of many non-penetrating through holes 1 provided on the surface of the wiring board 2 in a single treatment. The solvent can be applied, the processing speed can be easily increased, and the productivity can be improved. Further, in the method of immersing the wiring board 2 in the solvent, a large area on both front and back surfaces of the wiring board 2 can be processed at a time, and the solvent can be applied to the non-penetrating through-holes 1 on both surfaces. Further, the speed can be increased and the productivity can be increased.

After the inner periphery of the non-penetrating through hole 1 is wetted with the solvent as described above, the insulating resin 3 is applied to the surface of the insulating layer 12a of the wiring board 2 before the solvent evaporates.
The non-penetrating through hole 1 is filled with the insulating resin 3. The insulating resin 3 can be applied using curtain coating or the like, but the insulating resin 3 can be applied using a squeegee or a bar coater.
It is preferable that the insulating resin 3 is pressed into the non-penetrating through-holes 1 to be filled by applying. Squeegee is a plate-shaped member used for screen printing,
By supplying the insulating resin 3 to the surface of the wiring board 2 and rubbing the surface of the wiring board 2 with a squeegee, it is possible to press the insulating resin 3 into the non-penetrating through holes 1 while filling the insulating resin 3 with pressure. The bar coater is formed by winding a wire rod made of stainless steel or the like around the outer circumference of a rod made of stainless steel or the like without any gaps. Also in this bar coater, the insulating resin 3 is supplied to the surface of the wiring substrate 2 to cover the surface of the wiring substrate 2 with the bar. By rubbing with a coater, the insulating resin 3 can be pressed and filled into the non-through through holes 1 while being pressed. Although the pressure applied to the insulating resin 3 by the bar coater is weaker than the pressure applied by the squeegee, the external force exerted on the circuit 11 formed on the surface of the wiring board 2 is smaller than that exerted on the squeegee, and the circuit 11 may be broken. It will be less. The solvent can be applied to the inner circumference of the non-penetrating through hole 1 by using such a squeegee or a bar coater.

Further, the insulating resin 3 is provided in the non-through hole 1.
In filling the insulating resin 3, a plurality of insulating resins having different fluidity may be used, and the insulating resin 3 may be filled in the non-penetrating through holes 1 by sequentially coating the insulating resin 3 in order of good fluidity. The insulating resin 3 with good fluidity can be obtained by using a solvent having a high boiling point or by adjusting the concentration to a low viscosity by using a large amount of the solvent, and the insulating resin 3 with good fluidity can be obtained. Is used, the non-through through hole 1 can be filled well. On the other hand, however, such an insulating resin 3 having good fluidity takes time to dry, which causes a problem in productivity. Therefore, first, such an insulating resin 3 having good fluidity is applied and filled in the non-penetrating through holes 1, and then the insulating resin 3 having poorer fluidity than this, that is, a solvent having a low boiling point is used, or a solvent is used. By applying the insulating resin 3 adjusted to have a high viscosity by reducing the amount to a high concentration, the insulating resin 3 is applied to the wiring board 2 without lowering the productivity, and the through-hole 1 is satisfactorily applied. It can be filled.

Further, as described above, the insulating resin 3 is applied to the wiring board 2 to fill the non-penetrating through holes 1 with the insulating resin 3, and then the wiring board 2 is vibrated.
The non-penetrating through hole 1 can be completely filled with the insulating resin 3 while expelling voids and the like from the non-penetrating through hole 1, and the insulating resin 3 applied to the wiring board 2
The surface smoothness of the can be improved. When vibrating the wiring board 2 in this manner, the vibration frequency is in the range of 100 to 10000 Hz and the amplitude is 0.5 to 1 Hz.
It is preferable to set the vibration condition so as to be in the range of 000 μm.

As described above, the insulating resin 3 is applied to the wiring board 2 to fill the non-penetrating through-holes 1 with the insulating resin 3 and then the insulating resin 3 is dried.
As described above, the insulating layer 14 can be formed on the surface of the insulating layer 12a. Then, in this insulating layer 14, the non-penetrating through-hole 1 is formed in the same manner as described above, the circuit 11 is formed on the surface of the insulating layer 14, and the connection layer 13 is formed on the inner periphery of the non-penetrating through-hole 1. Through hole 1
By forming 5 and the connection layer 13 on the inner periphery thereof, a multilayer wiring board as shown in FIG. 2 can be manufactured.

[0018]

EXAMPLES Next, the present invention will be specifically described with reference to examples. (Example 1) 5 "Probimar 52" manufactured by Ciba-Geigy
000g, 1600 of the company's matting agent "DW91T"
g, 1000 g of the curing agent "XJ9001" manufactured by the same company, and 1300 g of thinner (a mixed solvent of 25% by weight of cyclohexanone and 75% by weight of methyl cellosolve) were taken, and these were mixed to prepare an epoxy photosensitive resin liquid.

Then, the resin solution is applied to one surface of the core inner layer substrate 10 formed of the epoxy resin laminated plate shown in FIG.
The insulating layer 12 having a thickness of 40 μm is dried by drying for a minute.
a was formed. Further, an insulating layer 12b having a thickness of 40 μm was similarly formed on the other surface of the core inner layer substrate 10. Then, a negative mask is overlaid on the surfaces of the insulating layers 12a and 12b, exposed, and developed to obtain a diameter of 150 mm.
A non-through hole 1 having a thickness of μm was formed. After this, the circuit 1 is formed on the surfaces of the insulating layers 12a and 12b by the semi-additive method.
1 was formed, and the inner periphery of the non-penetrating through hole 1 was plated to form the connection layer 13, thereby producing the wiring board 2 (FIG. 1B).

Next, the same thinner mixed with the above-mentioned photosensitive resin liquid is sprayed onto the non-penetrating through hole 1 formed in the insulating layer 12a of the wiring board 2 by using a sprayer, and the inner circumference of the non-penetrating through hole 1 is sprayed. Wet it with thinner. Next, before the thinner is dried, the above photosensitive resin liquid is used as the insulating resin 3 to coat the surface of the insulating layer 12a of the wiring board 2 with the curtain coater, and the insulating resin 3 is applied to the non-penetrating through holes 1. After filling, vibration frequency 1000H
By vibrating the wiring substrate 2 for 30 seconds under the conditions of z and amplitude of 10 μm, and drying at 90 ° C. for 20 minutes,
An insulating layer 14 having a thickness of 40 μm was formed (FIG. 1 (c)).

Thereafter, in the same manner as described above, the non-penetrating through hole 1 is formed in the insulating layer 14, the circuit 11 is further formed on the surface of the insulating layer 14, and the inner periphery of the non-penetrating through hole 1 of the insulating layer 14 is formed. A multilayer wiring board was produced by forming the connection layer 13 (FIG. 2). (Example 2) Multilayer wiring was performed in the same manner as in Example 1 except that thinner was applied to the surface of the insulating layer 12a of the wiring board 2 by a roll coater to wet the inner circumference of the non-through hole 1 with thinner. A plate was made.

Example 3 A multilayer wiring board was produced in the same manner as in Example 1 except that the wiring substrate 2 was dipped in thinner to wet the inner periphery of the non-through hole 1 with thinner. (Example 4) An epoxy-based photosensitive resin liquid was prepared in the same manner as in Example 1 except that the amount of the thinner compounded was 3000 g. Then, using this resin solution, insulating layers 12a and 12b are formed on both surfaces of the core inner layer substrate 10 in the same manner as in Example 1, and further non-penetrating through holes 1 are formed in the insulating layers 12a and 12b as in Example 1. Together with the circuit 11 and the connection layer 13
To form the wiring board 2 (see FIG. 1).
(B)).

Next, the same thinner as described above was applied to the surface of the insulating layer 12a of the wiring board 2 by a bar coater to wet the inner circumference of the non-through hole 1 formed in the insulating layer 12a with the thinner. Next, before the thinner is dried, the photosensitive resin liquid is used as the insulating resin 3 by a bar coater to coat the surface of the insulating layer 12a of the wiring board 2 and the insulating resin 3 is applied to the non-penetrating through holes 1. After filling, the wiring board 2 was vibrated in the same manner as in Example 1 and dried in the same manner as in Example 1 to form the insulating layer 14 having a thickness of 40 μm (FIG. 1).
(C)). Thereafter, a multilayer wiring board was produced in the same manner as in Example 1 (FIG. 2).

Example 5 A multilayer wiring board was produced in the same manner as in Example 1 except that a squeegee was used instead of the bar coater. (Example 6) An epoxy photosensitive resin liquid was prepared in the same manner as in Example 1 except that the amount of the thinner compounded was 3000 g (this is referred to as photosensitive resin liquid A). Further, an epoxy photosensitive resin liquid was prepared in the same manner as in Example 1 except that the amount of the thinner compounded was 5000 g (this is referred to as photosensitive resin liquid B).

Then, using the photosensitive resin liquid A, insulating layers 12a and 12b are formed on both surfaces of the core inner layer substrate 10 as in the first embodiment.
And the insulating layers 12a, 12 are formed in the same manner as in the first embodiment.
The non-penetrating through-hole 1 is formed in b and the circuit 11
The wiring board 2 was produced by forming the and connection layers 13 (FIG. 1B). Next, the same thinner as that described above was applied to the surface of the insulating layer 12a of the wiring board 2 by a curtain coater to wet the inner circumference of the non-through hole 1 formed in the insulating layer 12a with the thinner.

Next, before the thinner is dried, the photosensitive resin liquid B is used as the insulating resin 3 by a curtain coater to coat the surface of the insulating layer 12a of the wiring board 2 and the insulating resin is applied to the non-penetrating through holes 1. 3 was filled, and then the wiring board 2 was vibrated in the same manner as in Example 1 and dried in the same manner as in Example 1 to obtain the thickness 2
A first layer of 0 μm is formed, and a photosensitive resin liquid B is applied as an insulating resin 3 on the first layer by a curtain coater and dried in the same manner to form a second layer. The insulating layer 14 having the structure was formed (FIG. 1C). Thereafter, a multilayer wiring board was produced in the same manner as in Example 1 (FIG. 2).

(Comparative Example) The same as Example 1 except that the inner periphery of the non-through hole 1 is not wetted by applying thinner and the wiring board 2 is not vibrated after the insulating resin 3 is applied. Then, a multilayer wiring board was produced. A heat resistance test was conducted on each of the multilayer wiring boards produced as described above. The test is a pressure cooker test in which the multilayer wiring board is treated for 1 hour under the conditions of 121 ° C. and 100% RH, and then the multilayer wiring board is subjected to a solder bath at 260 ° C. for 10 hours.
It was immersed for 2 seconds and observed by observing the appearance change of the multilayer wiring board. The results are shown in Table 1.

[0028]

[Table 1]

As can be seen from Table 1, in each of the examples in which the inner periphery of the non-through through hole was wetted with a thinner, no swelling occurred and the appearance was normal.

[0030]

As described above, according to the present invention, a wiring board is manufactured by applying an insulating resin to the surface of a wiring board having non-penetrating through holes and filling the insulating resin in the non-penetrating through holes. In doing so, after wetting the inner circumference of the non-penetrating through hole with a solvent, the insulating resin was applied so that the non-penetrating through hole was filled with the insulating resin. The insulating resin wets the inner circumference of the non-penetrating through hole better, and the insulating resin smoothly flows into the non-penetrating through hole when the insulating resin is applied to the surface of the insulating layer. The resin can be filled well.

The invention of claim 2 is characterized in that the solvent is sprayed to wet the inner circumference of the non-penetrating through hole with the solvent, and the solvent can be sprayed and applied only to the necessary portions. The amount of solvent used can be saved. The invention of claim 3 is characterized in that a solvent is applied to the surface of the wiring board by a roll coater to wet the inner circumference of the non-penetrating through hole with the solvent. The solvent can be applied to the inner peripheries of the many non-penetrating through holes provided, and the productivity can be improved.

Further, the invention of claim 4 is characterized in that the wiring board is immersed in a solvent to wet the inner circumference of the non-penetrating through hole with the solvent. Then, the solvent can be applied to the non-penetrating through holes on both the front and back surfaces of the wiring board, and the productivity can be further improved. The invention of claim 5 is
It is characterized in that the non-penetrating through hole is filled with insulating resin by applying with a squeegee,
With a squeegee, the insulating resin can be pushed into the non-penetrating through hole to fill the non-penetrating through hole with high filling property.

The invention according to claim 6 is characterized in that the insulating resin is filled in the non-penetrating through holes by applying with a bar coater, and the insulating resin is pushed into the non-penetrating through holes with the bar coater. The non-penetrating through hole can be filled with the insulating resin with high filling property. Further, the invention of claim 7 is characterized in that a plurality of insulating resins having different fluidities are applied in order from the one having good fluidity, and the insulating resin is applied to the through-holes without lowering productivity. It can be filled well.

The invention of claim 8 is characterized in that the wiring board is vibrated when the insulating resin is filled in the non-penetrating through holes. The through-hole can be completely filled with the insulating resin.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, in which (a)
7A to 7C are cross-sectional views of each step.

FIG. 2 is a cross-sectional view of a wiring board according to the above embodiment.

[Explanation of symbols]

 1 Non-through through hole 2 Wiring board 3 Insulating resin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shingo Yoshioka, 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works Co., Ltd. 72) Inventor Shinichi Ikeya, 1048, Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Works Co., Ltd. (72) Hiroaki Fujiwara, 1048, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Inventor, Katsuhiko Ito, Osaka Prefecture 1048 Kadoma, Kadoma City, Matsushita Electric Works Co., Ltd. (72) Inventor, Kiyoaki Ihara, 1048 Kadoma, Kadoma City, Osaka Prefecture Osaka, Ltd. (72), Satoru Ogawa, 1048 Kadoma, Kadoma City, Osaka Matsushita Denko stock company

Claims (8)

[Claims] 1. A non-penetrating through hole is produced when a wiring board is manufactured by the steps of applying an insulating resin to a surface of a wiring board having a non-penetrating through hole and filling the insulating resin in the non-penetrating through hole. A method for manufacturing a wiring board, which comprises applying an insulating resin to the inner periphery of the non-penetrating through-hole and then filling the insulating resin with the insulating resin. 2. The method for manufacturing a wiring board according to claim 1, wherein a solvent is sprayed to wet the inner circumference of the non-penetrating through hole with the solvent. 3. The method for manufacturing a wiring board according to claim 1, wherein a solvent is applied to the surface of the wiring board by a roll coater to wet the inner circumference of the non-penetrating through hole with the solvent. 4. The wiring board is dipped in a solvent to wet the inner circumference of the non-penetrating through hole with the solvent.
3. The method for manufacturing a wiring board according to claim 1. 5. The method for manufacturing a wiring board according to claim 1, wherein the non-penetrating through hole is filled with the insulating resin by applying with a squeegee. 6. The method for manufacturing a wiring board according to claim 1, wherein the non-penetrating through holes are filled with the insulating resin by coating with a bar coater. 7. The method for manufacturing a wiring board according to claim 1, wherein a plurality of insulating resins having different fluidities are applied in order from the one having good fluidity. 8. The wiring board is vibrated when the non-penetrating through hole is filled with an insulating resin.
8. The method for manufacturing a wiring board according to any one of 7 to 7.