JPH03276795A - Multilayer laminated board and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a multilayer laminated board whose positional accuracy between layers is excellent by a method wherein the same reference holes are made in the multilayer laminated board which has laminated and united specific multilayer boards via insulating layers, in the specific multilayer boards and in prepregs, the holes are made to coincide and are fixed, metal foils are arranged and installed on outermost layers and this assembly is heated, pressurized and molded. CONSTITUTION:Two or more reference holes 8 are made in a multilayer laminated board of three or more layers, e.g. four layers, which are composed of metal foils 5 arranged and installed on surfaces of insulating layers 1, 1 formed by hardening a prepreg on both faces of a double-sided sheet 2. This assembly is fixed to a perforator; a plurality of reference holes 9, 9 are made in prescribed positions. Reference holes 9 are made in prescribed positions in films 10 for circuit formation use. The four-layer multilayer laminated board and the films 10 for circuit formation use are arranged by aligning the reference holes, and are exposed to light. The metal foils at outer layers of the four-layer laminated board are developed, etched and stripped off; circuits are formed; a four-layer board 4 is obtained. Separately, reference holes 9 are made in prepregs 3 in the same manner. The prepregs 3 are laid between two four-layer boards 4, 4; the metal foils 5, 5 are arranged and installed on both outer sides by laying the prepregs 3 in between; the reference holes 9 are made to coincide and are fixed; after that, hot plates are arranged at outer sides of the metal foils 5, 5; this assembly is heated and pressurized for a prescribed time by using press hot plates.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multilayer laminate and a method for manufacturing the same, and particularly relates to a high multilayer laminate and a method for manufacturing the same.

[Prior Art] Recently, as the density of printed wiring boards has increased, it has been expected that the multilayer laminates used therein will have good positional accuracy between the layers of the multilayer laminates for circuit formation. However, conventional multilayer laminates are made by laminating double-sided boards, single-sided boards, metal foils, etc. through an insulating layer made of hardened prepreg, and an example thereof is shown in FIG. This multilayer laminate is
Insulating layer 1 formed by hardening prepreg between four inner layer materials made of double-sided boards 2 and metal foil 5 disposed on the outside thereof.
It is an integrated laminated structure. These alignments are performed using guide holes drilled in the guide marks of the double-sided plate 2, and holes machined in the prepreg and metal foil according to design values. The positions of the guide marks on each double-sided plate 2 are slightly different due to differences in dimensional changes during lamination molding of the double-sided plate 2 and circuit formation. For this purpose, holes are drilled at the guide mark positions of the double-sided board 2, and in a multilayer laminate that is laminated and molded using prepreg with guide holes processed based on the guide marks, the inner layer material of the double-sided board 2, There is a problem that as the number of cured insulating layers of the prepreg increases, the positional accuracy between the layers decreases.

In addition, as the density of printed wiring boards has recently become higher, there has been a strong demand for the multilayer laminates used in the multilayer laminates to have good positional accuracy between the eyebrows for circuit formation. There are expectations for a manufacturing method that can produce products with good precision and that can efficiently produce multilayer laminates in response to the increasing demand for high-multilayer laminates with a large number of layers. However, printed wiring technology reader (
Conventional methods for producing multilayer laminates, such as the ■pin lamination method, ■mass lamination method, and ■sequential method described in Nikkan Kogyo Shimbun (published by Kinji Ito), have excellent workability and mass productivity. , it is not possible to obtain a multilayer laminate with excellent positional accuracy between the eyebrows. In other words, ■
In the bin lamination method, a prepreg of appropriate thickness is sandwiched between each inner layer material consisting of a double-sided board or a single-sided board, and the prepreg and copper foil or single-sided board are positioned on both the upper and lower sides with pins and overlapped, and then the multilayer Laminate and mold. This has disadvantages such as poor workability and poor mass productivity. ■In the mass lamination method, the inner layer material and prepreg are positioned and fixed using caulking pins, etc., and then multi-layer lamination molding is performed. In this case, both workability and mass productivity are good, but the positional accuracy is poor. ■Sequential method: After making a four-layer board using the usual method and forming a circuit, the outer layer is prepreg, one inner layer material, prepreg, and metal foil are layered in this order, and after the lamination is integrated, a circuit is formed on this metal foil. do. This process is repeated to form a multilayer laminate. In this case, there is a drawback that manufacturing takes too much time.

[Problem to be solved by the invention]

An object of the present invention is to provide a multilayer laminate with excellent interlayer positional accuracy, and a method for manufacturing the multilayer laminate with excellent workability, mass productivity, and excellent glabella positional accuracy.

[Means to solve the problem]

The present invention provides a multilayer laminate board characterized in that three or more multilayer boards are laminated together via an insulating layer, a multilayer board with three or more layers, and a prepreg, provided with the same reference hole, and It is an object of the present invention to provide a method for manufacturing a multilayer laminate, which comprises aligning and fixing the holes, disposing a metal foil on the outermost layer, laminating the sheets, and molding them under heat and pressure.

Here, a multilayer laminated #Fi board refers to a board with a circuit on the inner layer and metal foil on the outermost layer, and a multilayer board has a circuit on the inner layer and the metal foil on the outermost layer also has a circuit formed. say.

The present invention will be explained below based on the drawings.

As an embodiment of the multilayer laminate of the present invention, FIG. 1 shows a 10-layer multilayer laminate. An insulating layer 1.1 formed on the outside of the double-sided board 2, a prepreg layer between two four-layer multilayer boards 4.40 consisting of the circuit pattern arranged on the surface of the insulating layer 1, and the outside thereof. This is a multilayer laminate in which a hardened insulating layer 1 is formed, and metal foils 5 are disposed on both outer insulating layers 1.

Figure 2 shows one of the 12-layer multilayer laminates as another example.
Here's an example. In this product, one of the two four-layer multilayer boards 4 having the structure of the ten-layer multilayer board is replaced with a six-layer multilayer board 6.
It was changed to .

FIG. 3 shows another example of a 12-layer multilayer laminate as another embodiment. This thing has one double-sided plate 2 between two four-layer multilayer plates 4 having the structure of the ten-layer multilayer laminate.
This is a multilayer laminate formed by inserting an insulating layer 1 made of hardened prepreg.

FIG. 4 shows a 14-layer multilayer laminate as another embodiment. This is a multilayer laminate formed by replacing the double-sided board 2 of the 12-layer multilayer laminate structure shown in FIG. 3 with a four-layer board 4.

Note that instead of the metal foil described above, a single-sided plate or a double-sided plate having metal foil on one side can also be used.

The insulating layer, double-sided board, four-layer board, six-layer board, and metal foil constituting the multilayer laminate described above are each formed using the following materials.

First, a prepreg that is cured to form an insulating layer is obtained by impregnating a base material with a resin composition and drying it. This resin composition includes thermosetting resins such as phenol resins, unsaturated polyester resins, epoxy resins, polyimide resins, and modified resins of these resins, as well as thermosetting resins for the purpose of smoothly conducting or appropriately controlling the reactions of these resins. A resin composition is used in which a curing agent, curing accelerator, flame retardant, diluting solvent, etc. suitable for each resin are blended as necessary.

Glass cloth or the like is usually used as the base material impregnated with these resin compositions. In addition, inorganic fiber cloth such as quartz fiber cloth, organic fiber paper such as cellulose fiber paper, highly heat-resistant organic fiber cloth such as polyimide resin fiber cloth, etc. can be used in combination depending on the purpose.

The conditions for obtaining this dry prepreg are that the drying temperature is 110
Preferably, the temperature is 160°C. Drying at a temperature exceeding 160°C is undesirable because the resin hardens too much and the drying operation becomes difficult.

Dry prepreg is in the range generally referred to as the B stage in the curing process of thermosetting resins, and when heat is applied, the resin remelts and the curing reaction progresses, so even if you touch it with your hands, it will not melt. It is non-sticky and has properties that allow it to be stacked on top of each other.

The double-sided board can be obtained by stacking one or more of the above prepregs, stacking a metal foil on the outside thereof, and molding the prepreg under heat and pressure. A metal foil on the surface of which a circuit is formed and the surface is roughened can be normally used as an inner layer material for a multilayer laminate.

The four-layer board can be obtained by laminating a metal foil on the circuit surface of the outer layer of a double-sided board on which a circuit is formed and the surface is roughened, via one or more sheets of prepreg, and then forming the board under heat and pressure. A metal foil on the surface of which a circuit is formed and the surface is further roughened can usually be used.

The 6-layer board is made by placing a prepreg between two double-sided boards with a circuit formed using the pin lamination method, and then layering metal foil on the outer circuit surface of the two through the prepreg, fixing them with pins, and applying heat and pressure. It can be obtained by molding. In addition, as a sequential method, it can be obtained by stacking a prepreg on the outside of the four-layer board and a metal foil on the outermost layer in alignment with the guide pins, and molding them under heat and pressure. The 6-layer board obtained by any of the above methods can be usually used by forming a circuit on the metal foil on the surface and further roughening the surface.

As the metal foil, metal foils such as copper, aluminum, nickel, and stainless steel are preferred, and copper foil is particularly preferred since it has good electrical conductivity. In this case, either electrolytic copper foil or rolled copper foil may be used, and there is no particular limitation. Alternatively, the above metal foil in which a circuit is formed on the metal foil may be used.

Next, a method for manufacturing a multilayer laminate according to the present invention will be explained.

A method for manufacturing a multilayer laminate in which the same reference holes are provided in a multilayer board and a prepreg having three or more layers, the reference holes are aligned and fixed, metal foil is arranged on the outermost layer, the layers are laminated, and the multilayer board is heated and press-formed,
The steps will be explained below based on the drawings.

(1) The perspective view in FIG. 6 shows the insulating layer 1.1 formed by hardening the prepreg on both sides of the double-sided board 2,
It shows four layers formed in a conventional manner consisting of a metal foil 5 disposed on the surface of the metal foil 5.

Two or more temporary reference holes 8 are made in this four-layer multilayer laminate.

(2) Fix the four-layer multilayer board to the drilling machine by aligning the temporary reference hole 8 with a specific position of the drilling machine, and set the reference holes 9, 9, . . . of the present invention in the predetermined positions. In addition, the reference holes 9 are made at predetermined positions in the circuit forming film 10 by the same method or by another method.

(3) FIG. 7 shows a four-layer multilayer laminate and a film 10 for circuit formation on which a predetermined circuit is drawn, which are arranged with reference holes aligned and exposed.

(4) The cross-sectional view in FIG. 8 shows a four-layer board 4 obtained by developing, etching, and peeling off the outer metal foil of a four-layer multilayer board exposed using the circuit-forming film to form a circuit. show.

(5) Separately, the reference hole 9 is similarly drilled in the prepreg 3.

(6) The cross-sectional view in Fig. 9 is a schematic view of the combination of 10 multilayer laminates before they are laminated together, and one One or more sheets of the prepreg 3 are interposed, metal foils 5.5 are disposed on both outer sides thereof, and one or more of the prepregs 3 are interposed therebetween, and the reference hole 9 formed in each of these is inserted into the pin 10. After aligning and fixing the metal foil 5.5, a hot plate (not shown) is arranged on the outside of the metal foil 5.5, and the metal foil 5.5 is laminated and integrated by heating and pressurizing it for a predetermined time with a press hot plate through cushion paper. It is something to do.

(7) Figure 10 is a cross-sectional view of a 1° multilayer laminate obtained as a result of this process.

If one of the 4-layer boards mentioned above is replaced with a 6-layer board, a 12-layer multilayer laminate can be obtained, and if one 4-layer board is added in the same manner, a 14-layer multilayer laminate can be obtained. A multilayer laminate having more than this can be manufactured in the same manner.

Note that a double-sided plate or a single-sided plate can be used instead of the metal foil 5.

If the guide mark 7 of the double-sided board 2 is in accordance with the design value, the hole will be drilled at the position of the guide mark 7, and the temporary reference hole 8 will be drilled at the position of the guide mark 7, which is the inner layer material of the four-layer multilayer laminate. If the guide mark 7 drawn on the double-sided board 2 differs from the design value due to dimensional changes during lamination molding and circuit formation, the dimensional difference is calculated using one guide mark as a starting point. Temporary reference hole 8
In particular, deviation from the design value can be further reduced by dividing the difference between the guide marks and drilling the holes instead of drilling the holes.

In addition, when heat-pressing lamination molding is performed by inserting pins into the reference holes of each of the above constituent materials and aligning the laminated materials in multiple combinations, use a release film for each set or as needed. A laminate is formed by overlaying a metal foil such as copper foil on the outer layer surface, and after being stacked and mounted on a carrier plate, this laminate is inserted between the hot discs of a press and heated and press-formed to obtain a laminate. .

The conditions for molding this laminate vary depending on the resin, but the temperature is 140-180°C, the pressure is 30-90 kg.
/c+fl and the molding time is preferably 70 to 120 minutes.

[Effect]

In the multilayer laminate of the present invention, the positional accuracy between the layers is 3
One multilayer board with more than 9 layers can be made up of approximately 9 layers of one screen board, and by reducing the number of layers, the accuracy of the position between the eyebrows is improved.

In the method for manufacturing a multilayer laminate of the present invention, when forming a multilayer laminate using a multilayer board with three or more layers, the guide holes used when forming the multilayer board with three or more layers are used. The provisional reference hole of the present invention is used to prevent the positional deviation between the guide hole and the reference hole due to the difference in dimension changes during heating and pressure forming of a multilayer board of three or more layers when the reference hole is formed. By providing the reference hole of the present invention based on this,
A multilayer laminate with excellent workability and excellent glabella positioning accuracy can be obtained, and it can be mass-produced using conventional methods3.
This method is suitable for mass production of highly multilayered laminates of 8 or more layers, especially 10 or more layers, using a layered plate or a 4-layered plate.

〔Example〕

Example 1 Brominated epoxy resin (DER-511, E
100 parts by weight of K80 (manufactured by Dow Chemical), 3 parts by weight of dicyandiamide as a curing agent, 0.1 parts by weight of 2-ethyl-4-methylimidazole as a curing accelerator, and 55 parts by weight of an equal mixture of methyl ethyl ketone and dimethyl formamide as a solvent. A prepreg was obtained by impregnating a glass cloth base material of specification 7628 with a varnish of a resin composition containing each part by weight and drying it, and a copper foil with a thickness of 35 μm was applied to both outer surfaces of four sheets of this prepreg stacked. using a steam press at a molding temperature of 150°C and a molding pressure of 50k.
The inner layer material of the double-sided board was obtained by primary molding under the molding conditions of "g/cm" for 100 minutes. Four guide holes were drilled on each side of the outer frame of this inner layer material, and the holes were molded according to the holes. A test pattern circuit with a residual copper rate of 5% was formed on the copper foil on the surface of the inner layer material.This inner layer material and the four prepregs with the guide holes were stacked on the outside, and a thick layer was added on both outer surfaces. A 35 μm thick copper foil was placed and secondary molding was performed using a steam press at a molding temperature of 150° C., a molding pressure of 50 kg/cm”, and a molding time of 100 minutes to obtain a four-layer metal foil-clad multilayer laminate. Temporary reference holes are placed on two opposing sides of the outer frame of the four-layer metal foil-clad multilayer laminate at positions based on the difference between the distance between the guide holes and the design value distributed to each guide hole. N.C.
Drill 4 holes with a drill machine and drill these 4 temporary reference holes by NC.
It was fitted onto a fixed shaft of a drill machine, and four reference holes were drilled with an NC drill machine, one on each side of the outer frame of the four-layer board. A dry film for forming a circuit is pasted on the copper foil on both outermost surfaces, with four reference holes punched therein.
A circuit was formed by exposure and etching, and the surface of the formed copper circuit was further blackened. The prepreg having four reference holes is interposed between two four-layer boards whose surface copper circuits each having reference holes are blackened and on the outside thereof, and pins are inserted into these reference holes and fixed, and then Copper foil with a thickness of 18 μm was placed on both outermost surfaces, and using a steam press,
Molding temperature 150'C2 Molding pressure 50kg/cn+2.
Tertiary molding was performed under molding conditions for 100 minutes to obtain a 10-layer metal foil-clad multilayer laminate.

Two 300 mm square double-sided copper-clad multilayer laminates manufactured by this method were stacked together and placed on a 1.6III11 thick sacrificial board to form a 40.35 m grid with a pitch of 2.54 mm.
A hole of m is drilled under the conditions of a rotation speed of 8000 rpm and a feed rate of 305 μm/rev per rotation, and the positional deviation between the hole and the circuit pattern of each layer was measured at 50 locations to determine the amount of interlayer deviation. is shown in the tentative table.

Example 2 The same procedure as in Example 1 was carried out except that one of the four-layer plates in Example 1 was replaced with a six-layer plate.

Example 3 The same procedure as in Example 1 was carried out except that one double-sided plate having a reference hole and four prepregs were further added between the two four-layer plates of Example 1.

Example 4 The same procedure as in Example 3 was carried out except that the double-sided board in Example 3 was changed to a four-layer board.

Comparative Example 1 Five sheets of prepreg having the same reference holes were interposed between the two inner layer materials of the double-sided board having the reference holes of Example 1 and on the outside of the circle, and these reference holes were fixed with pins. Thereafter, secondary molding was performed using a steam press in the same manner as in Example 1 to obtain a 10-layer metal foil-clad multilayer laminate.

6 [Effects of the Invention] With the multilayer laminate of the present invention, a multilayer laminate with excellent positional accuracy between the eyebrows can be obtained, and a multilayer laminate with excellent interlayer positional accuracy can be produced with excellent workability and mass productivity. It can also be manufactured.

Table 1

[Brief Description of the Drawings] Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is a sectional view of another embodiment of the invention, and Fig. 3 is a sectional view of another embodiment of the invention. 4 shows a sectional view of another embodiment of the present invention, and FIG. 5 shows a sectional view of a conventional example. FIG. 6 is a perspective view of an embodiment of the present invention, FIG. 7 is a sectional view of the embodiment, and FIG. 8 is a sectional view of the embodiment, and FIG. 9 is a sectional view of the embodiment. Following FIG. 8, a sectional view of the embodiment is shown, and FIG. 10 is a sectional view of a conventional example. 1... Insulating layer 2... Double-sided board 3... Prepreg 4... 4-layer board 5... Metal foil 6... 6-layer board 7... Guide mark 8... Temporary reference Hole 9...Reference hole 10...Film 11...Pin 12...Guide hole

Claims (3)

[Claims] (1) A multilayer laminate, characterized in that three or more multilayer boards are laminated together with an insulating layer interposed therebetween. (2) The same reference hole is provided in the multilayer board and the prepreg with three or more layers, the reference holes are aligned and fixed, metal foil is placed on the outermost layer, the layers are laminated, and the material is heated and press-formed. A method for manufacturing a multilayer laminate. (3) The reference hole is drilled based on a temporary reference hole provided at a position to allocate a difference between a guide mark and a design value of the multilayer board having three or more layers. Method for manufacturing multilayer laminates.