JPS62236726A - Manufacture of multi layered substrate for additive process - Google Patents

Abstract

PURPOSE:To enable obtaining a multi layer substrate superior in heat resistance in soldering, dimensional stability, etc., and superior in qualities such as no warps, by putting a plied member having an inner layer plate between outer members in a flexible hermetic container, and while reducing pressure in the container, raising the pressure of gaseous territory in which the container is set up and applying pressure to the plied member to complete its formation. CONSTITUTION:A stainless plate 4 is laminated on both sides of a plied member which is formed by laminating each member so as to form a required constitution, and the whole is inserted into a flexible container 5 and they are set up in a vessel 7. Then a vacuum deaeration apparatus 6 is connected to the flexible container 5 and deaerates it, and when sufficiently reduced pressure is obtained inside the flexible container 5, the inner pressure of the vessel 7 is raised working the vacuum deaeration apparatus 6. The plied member is pressurized together with the flexible container by the pressure of a gas 8, and each member is integrally formed. Here as the flexible container is tightly sticked to the outer wall of the contents, the pressure from the gas 8 is applied to the plied member without hindrance. Furthermore it is possible to directly obtain a multi layer substrate provided with an adhesives layer 3a for additive process as the outer most layer through a laminate forming process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a multilayer board for additive method, and in particular, it has excellent solder heat resistance, dimensional stability, etc., and is suitable for forming circuit boards because it has no warpage. In addition to having good quality, it is possible to manufacture multilayer boards with excellent quality for forming wiring patterns using additive methods, such as electroless plating with good adhesion to the board and good performance. Regarding the method.

[Conventional technology]

Various configurations of substrates are used to form wiring patterns using the additive method, but when an inner layer circuit is provided within the substrate or various characteristics that cannot be obtained with a single layer configuration are required. For this, those having a multilayer structure are appropriately used.

For example, in a multilayer board for additive method, which has an inner layer board on which inner layer circuits etc. are provided, the inner layer board and an outer layer member such as a blip, which is appropriately selected depending on the configuration of the desired product, are connected between the inner layer board and the outer layer member. It has been manufactured by a method that includes a process of compression molding a composite material formed by stacking these members on top of each other so that each member is arranged in a desired arrangement to form a laminate molded product.

(Problems to be Solved by the Invention) When making a composite material into a laminated molded product using the conventional method as described above, it is necessary to compression mold the composite material using a very high press pressure of about 40 kg/cm2, for example. It was used. That is, by setting such a high press pressure, it is possible to prevent the generation of voids in the laminate molded product, particularly in the resin portion, which was noticeable at a low press pressure.

However, due to the high press pressure being applied during the compression molding process, the following new problems arise:
Conventional methods have not always been able to obtain good quality for multilayer substrates.

a) Even when a material with a sufficiently thick resin layer is used for the composite material, this resin layer is pressed and spread by high press pressure during molding, and the resin layer that is finally formed becomes thin.
When this resin layer functions as an insulating layer, a good withstand voltage cannot be obtained there. Or, when using prepreg, the resin flows during molding and the glass cloth used in the prepreg comes out from the resin.
This causes unevenness on the substrate surface, which causes defects in electroless plating.

b) In a composite material that uses both prepreg and additive adhesive layer, mixing occurs at the contact area between them, making it impossible to effectively utilize the additive adhesive layer placed on the substrate, resulting in no use. Poor adhesion of electrolytic plating is likely to occur.

On the other hand, when manufacturing multilayer substrates using mechanical pressure means such as a hydraulic press, press pressure is applied unevenly to the composite material.
It is unavoidable that layer thickness unevenness occurs in the resin layer in the multilayer board, and as a result, the resulting multilayer board may warp or
There was a problem that good dimensional stability and soldering heat resistance could not be obtained.

The present invention was made in view of the above-mentioned problems, and its purpose is to provide excellent soldering heat resistance, dimensional stability, etc.
Not only does it have good quality for forming circuit boards, such as no warping, but it also has good quality for forming wiring patterns using additive methods, such as good adhesion to the board and the ability to perform electroless plating. It is an object of the present invention to provide a method for manufacturing a multilayer board that is also excellent in terms of technology.

[Means for solving problems]

The above objects can be achieved by the following invention.

That is, in the method for manufacturing a multilayer substrate for additive method of the present invention, a composite material having an inner layer plate arranged between outer layer members is placed in a flexible container whose inside is airtightly partitioned from the outside. Then, the pressure inside the container is reduced in advance and/or while the pressure inside the container is reduced, the internal pressure of the gas region in which the container is placed is increased to apply pressure to the composite material in the container, and the mixture material is It is characterized by including a process of integrating and molding the constituent members.

Hereinafter, the method of the present invention will be explained in detail with reference to the drawings.

In the method of the present invention, first, for example, FIGS.
As in the example shown in (C), a composite material having a configuration corresponding to a desired multilayer board is formed.

The composite material shown in FIG. 1(a) has a prepreg 2 on the upper and lower surfaces of an inner layer substrate 1 on which an inner layer circuit is provided, and a member 3a consisting of an additive adhesive layer and a release film. They are formed by sequentially overlapping each other. In addition, the composite material shown in FIG. 1(b) includes a prepreg 2 on the upper and lower surfaces of an inner layer substrate 1 on which an inner layer circuit is provided, and a release film 3b.
It is formed by overlapping these in this order. Furthermore, the first
The composite material shown in Figure (C) is formed by overlapping a member 3a consisting of an additive adhesive layer and a release film on the upper and lower surfaces of an inner layer substrate l on which an inner layer circuit is provided. . Of course, the structure of the composite material formed in the present invention is not limited to these examples, and can take various forms as desired.

Note that the prepreg 2 constituting the composite material is appropriately selected from those used for forming multilayer substrates for additive methods. It goes without saying that two or more different prepregs 2 may be used in combination as desired.

Next, the composite material thus formed is inserted into a flexible container whose interior and exterior can be airtightly partitioned.

The flexible container referred to in the present invention is a container that is flexible enough to take on the shape of the contents, such as:
This means that it has enough flexibility to easily change its shape in response to deformation of the contents or in response to external forces.

Furthermore, the flexible container used in the present invention is one that has airtightness to the extent that depressurization treatment as described later can be effectively carried out.

Examples of such a flexible container include a bag-shaped container formed from a sheet of resin, metal foil, or paper or cloth impregnated with resin or the like.

The composite material inserted into the flexible container is processed through a laminate molding process as will be described in detail later, and each member constituting the composite material is integrated and molded to form a laminate molded product.

In the method of the present invention, this lamination molding process is carried out after the pressure inside the flexible container into which the composite material is inserted has been reduced in advance and/or while the pressure inside the container is reduced.

The term "depressurization treatment" as used in the present invention refers to a process in which the interior of the flexible container into which the composite material is inserted is degassed, and the interior thereof is depressurized and treated.

In the case where the pressure is reduced in advance, for example, as shown in FIG. After inserting the flexible container 5 into the flexible container 5, the inside of the flexible container 5 may be degassed by connecting the vacuum deaerator 6 thereto. In this way,
By degassing, the flexible container 5 is pressed against the surface of the contents, as shown in FIG. 2(b), and assumes a shape that conforms to the surface of the contents. Alternatively, as shown in FIG. 3, the flexible container 5 is placed in the gas region 7 where the lamination molding process is carried out,
Therefore, before carrying out the lamination molding process, the above-mentioned pressure reduction treatment may be carried out.

In addition, when carrying out the process simultaneously with the lamination molding process, the flexible container into which the composite material has been inserted is placed in the gas region 9 as shown in FIG. This may be carried out simultaneously with the lamination molding process.

Note that the degree of pressure reduction, temperature, treatment time, etc. in the pressure reduction treatment may be appropriately selected depending on the composition of the composite material used, or the operating conditions of the lamination molding process when carried out simultaneously.

For example, it is effective to reduce the pressure as much as possible on the equipment, and usually 100 mm and 1 g or less, preferably 20 m,
a+) Desirably 1 g or less. The lower the pressure during lamination molding, or when the fluidity of the prepreg or adhesive is low, it is better to sufficiently reduce the pressure.

By carrying out such a depressurization process in the flexible container, air bubbles can be removed from the resin in the composite material, thereby preventing the generation of voids therein. Furthermore, since the pressure applied to the composite material can be significantly reduced when the composite material is laminated and molded, it is possible to eliminate the problems mentioned above with conventional compression molding using high press pressure. ,On top of that,
A sufficient lamination molding process can also be carried out by pressurizing with gas.

In other words, since the press pressure applied to the composite material is low, the resin layer used in the components that make up the composite material may be pushed by the high press pressure and spread and become thin, or if prepreg is used for the component, the resin may flow. This prevents the glass cloth of the prepreg from coming out from the resin and causing unevenness on the substrate surface.

Note that it is important that the resin layer has a sufficient layer thickness in this way in order for the resin layer to function as an insulating layer and to obtain a sufficient withstand voltage. This becomes even more important when the inner layer board is provided with an inner layer circuit.

On the other hand, even when molding a composite material using a prepreg and an additive adhesive layer, the additive adhesive layer is not pressed onto the prepreg more than necessary, so the resin used for the prepreg and the additive adhesive layer There is no possibility that the adhesive for the additive method cannot be used effectively due to the mixing of the two.

In the present invention, whether the reduced pressure treatment is performed prior to and/or simultaneously with the lamination molding process can be determined based on the characteristics of the prepreg and the adhesive used. For example, if the characteristics of the resin used are that the resin flow is extremely small, it is desirable to perform a vacuum treatment before the lamination molding process, sufficiently deaerate the resin, and then perform a vacuum treatment during the lamination molding process as well.

In the lamination molding process of the present invention, a flexible container with a composite material inserted is placed in a region filled with gas, and the internal pressure (gas pressure) in the region is increased under appropriate temperature conditions. This is carried out by applying pressure to the composite material in the container and using the function of the resin disposed as a component of the composite material to press and integrate each member. Therefore, operating conditions such as temperature, processing time, gas pressure, etc. in this lamination molding process depend on each member making up the composite material, especially the type of resin or inner layer plate used for prepreg, etc., or whether the composite material has been previously subjected to reduced pressure treatment. The appropriate selection is made depending on whether the However, in the method of the present invention, the composite material is subjected to depressurization treatment at an appropriate stage, so the gas pressure during this lamination molding process can be reduced to about 174 to 178 ℃ compared to when no depressurization treatment is performed. The effects described above can be effectively obtained.

Moreover, by carrying out the lamination molding process using a pressurization method that uses gas pressure, it is always possible to apply uniform pressure to the composite material from its surroundings, making it possible to use conventional mechanical pressurization methods. To always obtain a multilayer board with excellent quality such as preventing the occurrence of uneven layer thickness of the resin layer due to uneven pressurized conditions, excellent soldering heat resistance and dimensional stability, and no warping as in the method described above. becomes possible.

Hereinafter, an example will be described in which, in the method of the present invention, the pressure inside the flexible container is reduced in advance and the pressure in the flexible container is reduced during the lamination molding process.

First, as shown in Figure 3, stainless steel supporting plates are placed above and below a composite material formed by overlapping each member in a desired configuration (here, the configuration shown in Figure 1 (a)). The plates 4 are placed one on top of the other and inserted into a flexible container 5, which in turn is placed in a container 7 forming a region of gas 8.

Next, with the vacuum deaerator 6 connected to the flexible container 5, the vacuum deaerator 6 is operated to degas the inside of the flexible container 5. This degassing causes the flexible container 5 to deform as shown in FIG. 2(b). When a sufficiently reduced pressure state is obtained inside the container, the internal pressure of the container 7 (pressure of the gas 8) is increased while further operating the vacuum deaerator 6. Then, the composite material together with the flexible container S is pressurized by the pressure of the gas 8, and each member constituting the composite material is integrally molded. At this time,
The flexible container 5 has already been deformed by the previous degassing and is in close contact with the outer wall of the contents, so that the pressure from the gas 8 can be applied to the mixture without any problem. The internal pressure of the container 7 can be selected variously as mentioned above, for example, 5 to 2.
It can be about 5 kg/cm'.

Note that in order to increase the internal pressure of the container 7, methods such as sending gas 8 into the container 7 or reducing the volume of the container 7 can be applied.

In addition, as in the example shown in Fig. 3, when using a composite material having the structure shown in Fig. 1(a) or when using a composite material having the structure shown in Fig. 1(C), the lamination molding process is Through this process, a multilayer substrate having an additive adhesive layer provided on the outermost layer can be directly obtained. In addition, when using a composite material having the structure shown in FIG. 1(b), after peeling off the release film from the M-layer body obtained after the laminated molding process, an adhesive for additive method is applied to the predetermined surface. A multilayer substrate can be obtained by coating by a coating method using a procoater, a roll coater, or the like, and curing the coating.

〔Example〕

Hereinafter, the present invention will be explained in more detail according to Examples.

Example 1 Inner layer board 1 manufactured by Toshiba Chemical on which an inner layer circuit is formed (
Thickness: 0.6mm) and manufactured by Toshiba Chemical (product number:
TLP-55] prepreg 2 (thickness: 0.2 m
Fig. 1(a) shows a sheet 3a (made by DuPont Tetra film coated with N0R-phenolic resin adhesive) and a sheet 3a consisting of an adhesive layer for additive method and a release film. They were stacked on top of each other in the same manner as before to form a composite material. In addition, the outermost layer of this composite material is sheet 3.
The release film shown in a was placed in the same position.

Next, this composite material is inserted into a bag-like container 5 made of nylon, and then placed in a container 7 filled with air 8 having the structure shown in FIG. and vacuum deaerator 6
was connected.

Note that the container 7 is provided with a device (not shown) for feeding air into the container to increase its internal pressure.

In this state, the vacuum deaerator 6 is operated, and the flexible container 5
After the inside of the container is degassed and a sufficient reduced pressure state is obtained in the container, air is fed into the container 7 while operating the deaerator 6 to increase the internal pressure to about 14 kg/CII + 2, thereby making the container flexible. A multilayer substrate for additive method was obtained by applying pressure to the composite material in the container 5 and carrying out a lamination molding process.

The degree of degassing in the flexible container 5 was 5 mmHg, and the temperature in the container 7 was 170°C.

Furthermore, the above operation was repeated to obtain a large number of multilayer substrates for additive method. Two pieces arbitrarily selected from the obtained substrates (
Using sample AIILI-1-1-2), tests regarding the following items were conducted and evaluated. The results are shown in Table 1.

a) Layer thickness of resin layer; The layer thickness of the resin layer formed from the prepreg and additive adhesive layer on each substrate was measured, and the upper and lower limits of the theoretical thickness were shown.

b) Occurrence of voids in resin layer: By visually observing the laminate molded product, it was tested whether or not voids were generated in the resin layer formed from the prepreg and the additive adhesive layer. Those in which the occurrence of voids was significantly observed were marked as O, and those in which no voids were observed were marked as ×.

C) Smoothness of the substrate surface: The surface of each substrate was inspected using a surface roughness meter and tested to see if there was any noticeable unevenness on the substrate surface. Those that were not approved were marked as 0, and those that were not approved were marked as ×.

d) Occurrence of defective areas during circuit pattern formation: After peeling off the release film from the substrate and roughening the exposed adhesive, a plating catalyst is attached thereto, and then a plating resist is applied to areas other than the circuit pattern. After the formation, a circuit pattern is formed on each board using an additive method using electroless plating, and the circuit pattern is visually observed to see if any defective areas have occurred. Those in which O1 was not recognized were marked as ×.

e) Adhesion of the circuit pattern; Evaluate the adhesion of the circuit pattern formed on the substrate surface in d) above to the substrate surface by measuring the peel strength,
Those that were good were marked as O1 and those that were poor were marked as ×.

f) Warpage: Each board was placed on a surface plate and tested with a feeler gauge to see if there was any warpage on the board. Those where warpage was observed were rated O, and those where no warpage was observed were rated x.

g) Soldering heat resistance; After cutting the board whose surface was electroless copper plated in d) above into a size of 25x25nun,
Even after floating it on a solder plate at 0℃ for more than 20 seconds, it does not swell.
Those in which no peeling occurred were rated as x, and those in which blistering and peeling occurred within 0120 seconds were rated as x.

Example 2 Inner layer board 1 manufactured by Toshiba Chemical on which an inner layer circuit is formed (
Thickness: 0.8 mm) and a sheet 3a consisting of an adhesive layer for additive method and a release film (a Tetra film made by DuPont Co., Ltd. coated with N0R-phenolic resin adhesive) are shown in Fig. 1. A composite material was formed by overlapping each other in the same manner as shown in (C).

Note that the release film of the sheet 3a was positioned at the outermost layer of this composite material.

Next, this composite material was laminated and formed in the same manner as in Example 1 to obtain a large number of multilayer substrates for additive method.

Two arbitrarily selected samples (Samples A1112-1 to A1112-2-2) from the multilayer substrates for additive method obtained in this manner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Note that the resin layer in the multilayer substrate obtained in this example was formed from an additive adhesive layer.

Comparative Example 1 After stacking anti-stainless steel plates on top and bottom of a composite material having the same structure as that used in Example 1, the plates were inserted between the hot plates of a hydraulic press, the hydraulic press was operated, and the hot plate by 170
℃ and 14 kg/cm2 to integrally mold each member constituting the composite material, and this operation was repeated to obtain a large number of multilayer substrates for additive methods.

Two pieces arbitrarily selected from the obtained substrates (sample A11-1
~1l-2) was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 A large number of multilayer substrates for additive method were obtained in the same manner as Comparative Example 1 except that the press pressure of the composite material was 40 kg/cm 2 .

Two arbitrarily selected substrates from the obtained substrates (sample A12-1
-12-2) were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[Effects of the Invention] In the method of the present invention, the following effects can be obtained by subjecting the composite material to reduced pressure treatment and carrying out the lamination molding process using a pressurization method using gas.

a) The vacuum treatment effectively removes air bubbles in the resin and prevents the generation of voids.

b) Due to the reduced pressure treatment, low press pressure can be applied to the lamination molding process of composite materials, reducing the layer thickness of the resin layer as in the conventional high press pressure method, and reducing the thickness of glass cloth etc. when using prepreg. Since it is possible to prevent the occurrence of unevenness on the surface of the substrate due to embossment, which causes defects in electroless plating, it is possible to form a resin layer with a sufficient thickness and to obtain good smoothness on the surface of the substrate.

C) Even when molding a composite material using a prepreg and an additive adhesive layer, the additive adhesive layer is not pressed onto the prepreg more than necessary, so the resin used for the prepreg and the additive adhesive layer are There is no possibility that the function of the Aditig adhesive will deteriorate due to mixing of the two.

d) It is always possible to apply uniform pressure to the composite material from the surrounding area, which eliminates uneven layer thickness of the resin layer due to uneven pressurization, unlike in methods using conventional mechanical pressure means. It is possible to always obtain a multilayer board with excellent quality such as prevention of occurrence, excellent soldering heat resistance, dimensional stability, etc., and no warping.

Therefore, according to the present invention, it has become possible to supply a multilayer board with excellent quality not only for forming a circuit board but also for forming a wiring pattern by an additive method.

[Brief explanation of drawings]

FIGS. 1(a) to (C) are side views showing examples of the composition of the composite material used in the method of the present invention, and FIGS.
b) is a schematic diagram of the composite material placed in a flexible container to show the depressurization process in the method of the present invention, and Figure 3 is a schematic diagram of the composite material placed in a gaseous state to show the layered molding process in the method of the invention. It is a typical schematic diagram at the time of arrangement|positioning in a area|region. 1; Inner layer plate 2; Prepreg 3a: Sheet 3b consisting of additive adhesive layer and release film; Type III film 4; Stainless steel plate 5; Flexible container 6; Vacuum degassing device 7; Forms gas region Container 8: Gas

Claims (1)

[Claims] 1) In a flexible container whose inside is airtightly partitioned from the outside, a composite material having an inner layer plate arranged between outer layer members is placed, and the inside of the container is preliminarily inspected. The pressure is reduced and/or while the pressure inside the container is reduced, the internal pressure of the gas region in which the container is placed is increased to apply pressure to the composite material in the container, thereby integrating each member constituting the composite material. 1. A method for manufacturing a multilayer substrate for an additive method, the method comprising a step of molding. 2) The method for producing a multilayer substrate for additive method according to claim 1, wherein the composite material has an inner layer plate sandwiched between prepregs. 3) The method for producing a multilayer substrate for additive method according to claim 1 or 2, wherein the composite material has a member having an adhesive layer for additive method disposed in its outermost layer. 4) The method for manufacturing a multilayer substrate for additive method according to any one of claims 1 to 3, wherein the inner layer board is provided with an inner layer circuit.