JPH10303552A - Manufacture of multilayred printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a multilayered printed wiring board wherein a plurality of intermediate products for a multilayered board are arranged and integrally formed between heating platens, a plurality of multilayed boards are manufactured at the same time, generation of the board of large warp can be reduced when the obtained multilayered board is worked in a multilayred printed wiring board, and yield can be improved. SOLUTION: In this manufacturing method, inner layer material, prepreg, and a metal foil or a metal foil clad outer layer material are so stacked that the metal foil is formed on the outermost side, and an intermediate product 5 is formed. A plurality of the intermediate products 5 are stacked by laminating interposing plates 6. The stacked member 7 is arranged between an upper and a lower heating plates 9 interposing cushion members 8, and then lamination- molded by heating and pressing. In this case, sacrifice members 11 formed by sandwiching prepreg 3 between copper foils 10, 10 and the plates 6 are so arranged that the plates 6 come into contact with the cushion members 8.

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 printed wiring board, and more particularly, to an intermediate product comprising an inner layer material having an inner layer circuit formed thereon, a prepreg, and a metal foil or a metal foil-clad outer layer material. The present invention relates to a lamination technique for simultaneously integrating a plurality of sheets.

[0002]

2. Description of the Related Art Conventionally, an intermediate product is formed by laminating an inner layer material having an inner layer circuit, a prepreg, and a metal foil or a metal foil-clad outer layer material. After forming a laminated board (hereinafter, referred to as a multilayer board), the multilayer board is processed to manufacture a multilayer printed wiring board. First, as shown in FIG. 2, an inner layer material 2 on which an inner layer circuit 1 is formed, a prepreg 3, and a metal foil 4 will be described.
(Or a metal foil-clad outer layer material) is overlapped so that the metal foil 4 is on the outermost side to form an intermediate product 5. A plurality of the intermediate products 5 are stacked via a plate 6 made of stainless steel or the like so that the plate 6 is located on the outside, to form a load 7, and then, as shown in FIG. Are arranged between the upper and lower hot plates 9, 9 with a cushion material 8 made of paper, rubber or the like interposed therebetween, and then heated and pressed to form a laminated plate, thereby producing a multilayer board. However, in order to arrange a plurality of intermediate products 5 between the hot plates 9 and 9 and integrate them simultaneously,
It is considered that the heating speed at the start of molding is different depending on the molding position. However, when the obtained multilayer board was processed into a multilayer printed wiring board, there was a problem that a multilayer printed wiring board having large warpage was generated. In particular, there was a tendency that the warpage of the multilayer board formed at a position close to the hot plate was large.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to arrange a plurality of intermediate products between a hot plate and a multi-layer plate. A method of manufacturing a multilayer printed wiring board in which a plurality of multilayer boards are manufactured at the same time, and when the obtained multilayer board is processed into a multilayer printed wiring board, occurrence of a multilayer printed wiring board having a large warp is reduced. It is an object of the present invention to provide a manufacturing method which can reduce the number of manufacturing steps and can thereby improve the yield.

[0004]

According to a first aspect of the present invention, there is provided a method of manufacturing a multilayer printed wiring board, comprising: forming an inner layer material having an inner layer circuit, a prepreg, and a metal foil or a metal foil-clad outer layer material on the outermost side. An intermediate product is formed by stacking the metal foil so that the intermediate product is formed, and a plurality of the intermediate products are stacked via the plate and the plate is positioned outside, and the stacked material is interposed between the upper and lower parts by the cushion material. In the method for manufacturing a multilayer printed wiring board to be arranged between hot plates and then laminated by heating and pressing, between the cushion material and the load, a waste material and a plate formed by sandwiching a prepreg between copper foils,
The plate is arranged so as to be in contact with the cushion material.

According to a second aspect of the invention, there is provided a method of manufacturing a multilayer printed wiring board according to the first aspect, wherein the thickness of the waste material after molding is 0.8 to 2.0 mm. .

According to a third aspect of the present invention, there is provided the method for manufacturing a multilayer printed wiring board according to the first or second aspect, wherein the prepreg used as the waste material is a glass cloth base material, It is characterized in that the content is 35 to 40% by weight.

In the present invention, since the waste material is interposed between the cushion material and the load constituted by sandwiching the intermediate product between the plates, and the intermediate product is formed, the intermediate product at a position close to the hot platen is heated. Since the heating rate at the start of molding with the intermediate product located far from the platen is made uniform, the tendency of the multilayer plate molded near the platen to have a large warpage is alleviated. That is, for the intermediate product near the hot platen, the temperature difference between the start of heating of the surface closer to the hot platen and the surface farther from the hot plate until the molding temperature is reached (the temperature of the front and back surfaces). Difference), and as a result, the occurrence of distortion that causes warpage is reduced.

The thickness of the waste material after molding is 0.8 to 2.0 m
m, the temperature difference between the start of heating of the surface closer to the hot platen and the surface farther from the hot platen to the molding temperature for the intermediate product at a position close to the hotplate is greater. It will surely be smaller.

When the base material of the prepreg used as a discarded material is a glass cloth base material, if the content of the resin component is 35 to 40% by weight, the occurrence of abnormalities called molding misalignment during molding may occur. Is suppressed.

[0010]

DETAILED DESCRIPTION OF THE INVENTION As in the prior art, FIG.
As shown in FIG. 5, an intermediate product 5 is formed by laminating an inner layer material 2 on which an inner layer circuit 1 is formed, a prepreg 3, and a metal foil 4 (or a metal foil-clad outer layer material) such that the metal foil 4 comes to the outermost side. I do. As a material for forming the inner layer material 2 and the metal foil-clad outer layer material, for example, a glass cloth base epoxy resin copper-clad laminate, a glass cloth base polyimide resin copper-clad laminate, or the like can be used. Can be used a glass cloth base epoxy resin prepreg or a glass cloth base polyimide resin prepreg. Examples of the metal foil 4 used in the present invention include a copper foil, a nickel foil, and an aluminum foil.

Next, a plurality of intermediate products 5 are stacked via a plate 6 made of stainless steel or the like and the plate 6 is positioned outside to form a load 7. Then
As shown in FIG. 1, the load 7 is disposed between the upper and lower hot plates 9 with a cushion material 8 made of paper, rubber or the like interposed therebetween. Between,
Discarded material 11 formed with prepreg 3 sandwiched between copper foils 10
And the plate 6 is arranged such that the plate 6 is in contact with the cushion material 8. The waste material 11 referred to here is different from the intermediate product 5 for forming a multilayer board, and is constituted by the copper foil 10 and the prepreg 3 and does not include the inner layer material. That is, the waste material 11 is not used as a multilayer board after molding. When the thickness of the discarded material 11 after forming is 0.8 mm or more, heating of the intermediate product at a position close to the hot platen on the surface near the hot platen and on the surface far from the hot platen is started. This is preferable because the temperature difference from the time until the temperature reaches the molding temperature is more reliably reduced, and as a result, the occurrence of distortion that causes warpage is further reduced. However, if the thickness exceeds 2.0 mm, the heat conduction becomes slow and the prepreg 3
A new problem arises in that the molding time for curing the resin component must be lengthened.
Is preferably in the range of 0.8 to 2.0 mm.

The prepreg 3 used for the waste material 11
When the base material is a glass cloth base material, if the content of the resin component is less than 35% by weight, the effect of reducing warpage becomes insufficient due to rapid heat conduction, and if the content exceeds 40% by weight. It is preferable that the content of the resin component is in the range of 35 to 40% by weight, since abnormalities called molding deviation in the molding step are likely to occur.

In the present invention, between the cushion material 8 and the load 7, the waste material 11 and the plate 6, which sandwich the prepreg 3 between the copper foils 10, are placed such that the plate 6 contacts the cushion material 8. In the arranged state, a multilayer board is manufactured by heating and pressing. The heating and pressing conditions are not particularly limited, and may be appropriately determined depending on the type of raw materials such as prepreg to be used.

[0014]

The present invention will be described below based on examples and comparative examples.

An inner layer material having an inner layer circuit formed on both sides was prepared using a glass cloth base epoxy resin copper-clad laminate having a substrate thickness of 0.8 mm. Then. Two glass cloth-based epoxy resin prepregs each having a thickness of 0.18 mm are arranged on both outer sides of the inner layer material, and a copper foil is further arranged on the outer side of each one.
The sheets were arranged and laminated to obtain an intermediate product.

In the first and second embodiments, the intermediate product is constructed by using a discarded material as shown in FIG. 1, and in the comparative example 1 by the construction without using the discarded material as shown in FIG. Were placed between hot plates and laminated to form a multilayer board. In the molding, the hot plate was heated to 170 ° C., heated and pressed at a pressure of 30 kg / cm ² for 120 minutes, and then cooled to room temperature while maintaining the pressure.

In Example 1, a waste material having a thickness of 0.2 mm after molding was used. In Example 2, a thickness of 1.0 m after molding was used.
m, and no waste material was used in Comparative Example 1. The thickness of the discarded material after molding represents the thickness including the copper foil.

(1) Difference in temperature between the front and back of the intermediate product when the hot platen reaches a predetermined temperature: After a heating medium of 170 ° C. is supplied to the hot platen to start heating, the hot platen is heated to a predetermined temperature ( 90 ° C,
The temperature difference between the front and back of the intermediate product (the intermediate product closest to the hot platen and the intermediate product far from the hot platen) when the temperature reached 130 ° C and 170 ° C) was measured. In addition,
The intermediate product far from the hot platen is an intermediate product molded at the position of the fifth sheet from the outside. From the results in Table 1, the temperature difference between the front and back of the intermediate product closest to the hot plate is smaller in the cases of Examples 1 and 2 using the waste material than in the case of the comparative example. It was confirmed that the temperature difference between front and back was smaller in Example 2 using a waste material of 1.0 mm than in Example 1.

[0019]

[Table 1]

(2) Amount of warpage when the obtained multilayer board was processed: The amount of warpage when the multilayer board obtained after forming was processed was measured. The measuring method is a method in which the outer layer copper foil of the multilayer board is entirely etched (size: 600 mm × 50).
0 mm) was used as a test piece, and the test piece was heat-treated at 170 ° C. for 15 minutes, cooled to room temperature, allowed to stand on a reference horizontal surface, and the maximum lift was measured as the amount of warpage. The amount of warpage (mm) was converted into the amount of warpage (%) by the following formula. Warpage (%) = [Warp (mm) / 600 (mm)] ×
100 The sample used for the measurement of the amount of warpage is a multilayer plate 1 formed at the position closest to the hot plate in the obtained multilayer plate for each molding.
And a multilayer board formed at a position distant from the hot plate (fifth position from the outside) was used as a sample. A total of 10 moldings were performed, and the above test specimens were prepared from each of the obtained 10 samples, the amount of warpage was measured, and the average, maximum, and minimum values of the obtained 10 warpages were determined. The results are shown in Table 2 in terms of%. Table 2
From the results of the above, in the case of Example 1 and Example 2 using the waste material, the amount of warpage when processing the multilayer board was smaller than in the case of the comparative example, and the molding was particularly performed at a position close to the hot platen. It was confirmed that the amount of warpage was greatly improved in the obtained multilayer board. Further, it was confirmed that the degree of improvement in the amount of warpage was more remarkable in Example 2 using the waste material having a thickness of 1.0 mm than in Example 1.

[0021]

[Table 2]

The discarded material having a thickness of 1.0 mm after molding used in Example 2 was a prepreg of a glass cloth base material between copper foils and having a resin content of 40% by weight. No misalignment occurred during molding, but the discarded material consisted of 5 prepregs of glass cloth base material with a resin content of 47% by weight between copper foils. When they were overlapped, molding deviation occurred during molding.

[0023]

According to the method for manufacturing a multilayer printed wiring board according to the first and second aspects of the present invention, a waste material is interposed between a cushion material and a load constituted by sandwiching an intermediate product between plates. Since the heating speed at the start of molding is uniform between the intermediate product near the hot platen and the intermediate product far from the hot platen, the multilayer formed at a position near the hotplate The tendency that the warpage of the plate is large is alleviated. That is, for the intermediate product at a position close to the hot platen, the temperature difference between the start of heating of the surface closer to the hot platen and the surface farther from the hot plate until the molding temperature is reached is reduced. As a result, distortion that causes warpage is reduced. Therefore, according to the method for manufacturing a multilayer printed wiring board according to the first and second aspects of the present invention, when the obtained multilayer board is processed into a multilayer printed wiring board, generation of a multilayer printed wiring board having a large warp is prevented. Therefore, the yield can be improved.

According to a third aspect of the present invention, there is provided the method for manufacturing a multilayer printed wiring board, wherein the base material of the prepreg used as the waste material is a glass cloth base material, and the content of the resin component is 3%.
Since the content is within the range of 5 to 40% by weight, in addition to the above-described effects, an effect of suppressing occurrence of abnormalities called molding deviation during molding is also exerted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of the present invention.

FIG. 2 is a sectional view for explaining an intermediate product.

FIG. 3 is a cross-sectional view for explaining a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner layer circuit 2 Inner layer material 3 Prepreg 4 Metal foil 5 Intermediate product 6 Plate 7 Loaded material 8 Cushion material 9 Hot platen 10 Copper foil 11 Discard material

Claims (3)

[Claims] An intermediate product is formed by laminating an inner layer material forming an inner layer circuit, a prepreg, and a metal foil or a metal foil-clad outer layer material so that a metal foil comes on the outermost side. A multi-layer printed wiring board, which is stacked between the upper and lower hot plates with a cushion material interposed therebetween, and then heated and pressed to form a laminate. In the manufacturing method, between the cushion material and the load, a discarded material and a plate formed by sandwiching a prepreg between copper foils are arranged such that the plate is in contact with the cushion material. Manufacturing method. 2. The thickness of the waste material after molding is 0.8 to 2.0.
2. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein 3. The multilayer printed wiring according to claim 1, wherein the prepreg used as the waste material is a glass cloth base material, and the content of the resin component is 35 to 40% by weight. Plate manufacturing method.