JPH06224553A - Manufacture of multilayer printed board - Google Patents

Abstract

PURPOSE:To prevent layer deviation by using core material which has four or less layers with an internal layer circuit which is laminated by masslamination system and laminating outer layer copper foil on the top and bottom by pin lamination system. CONSTITUTION:Core material 20 is formed of four layers by mass lamination system. The core material 20 has an internal layer circuit L3 on the one plane of the internal insulating layer and an internal layer circuit L4 on the other plane. Copper coil 20a is adhered on the front plane of the insulating layer on the external side of the internal layer circuit L3 and copper foil 2Ob is adhered on the front plane of the insulating layer on the external side of the internal layer circuit L4. A reference pin 11 is permitted to fit in each reference hole 10, an external layer foil 4, a prescribed sheets of prepreg P, the core material 20, an external layer copper foil 3 and a pressing plate 14 are placed on a pressing plate 13 in such order. Then, the layers are heated and pressurized by heat press to be adhered and cured and a six layer printed board provided with the internal layer circuits L2, L3, L4 and L5 in the internal layer, the external layer copper foil 3 adhered on the front plane and the external layer copper foil 4 adhered on the rear plane is formed.

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. To laminate a multilayer printed wiring board, a reference pin is used to stack a core material having an inner layer pattern, a prepreg, and an outer layer copper foil between the laminated layers, and heat is applied by hot pressing.
There are a pin lamination method in which pressure is applied to bond and cure, and a mass lamination method in which heating and pressure are applied to bond and cure without using a reference pin.

The mass lamination method is inexpensive because a large number of multi-layer printed wiring boards can be obtained by using a copper clad laminate having a desired large size. However, since the stacking accuracy (positioning accuracy between layers) is low, small vias, I
When applied to a VH (Interstial Via Hole) or a multilayer printed wiring board having a fine pattern, a layer shift often occurs.

Therefore, when a device maker requires a multilayer printed wiring board of up to about four layers, an inexpensive multilayer printed wiring board manufactured by a mass lamination method is purchased from a laminated maker, and after the purchase, the circuit of the surface layer is manufactured. Forming,
The desired mounting parts are mounted.

On the other hand, the pin lamination method is higher in cost than the mass lamination method, but the stacking accuracy is high. Therefore, conventional small-diameter vias, IV
A multi-layer printed wiring board having an H or fine pattern is manufactured by a device manufacturer in-house by a pin lamination method and mounted components are not purchased from a laminated manufacturer.

[0005]

2. Description of the Related Art A six-layer printed wiring board will be described below as an example.
A conventional manufacturing method (pin lamination method) of a device manufacturer will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a copper foil 1a on the surface of the base material.
A double-sided copper-clad laminate having a copper foil 1b adhered to the back surface thereof. The copper foil has a thickness of 35 μm to 70 μm, and the thickness of the double-sided copper-clad laminate varies depending on the number of layers of the multilayer printed wiring board.
The thickness is approximately 0.25 mm in the case of layers and approximately 0.1 mm in the case of 12 layers.

No. 2 is a copper foil 2a on the surface of the base material and a copper foil 2a on the back surface.
2b is a double-sided copper-clad laminate having the same dimensions as the double-sided copper-clad laminate 1, each of which is adhered. 3 and 4 are copper foils for outer layers whose foil thickness is about 0.18 μm and whose outer shape is equal to that of the double-sided copper clad laminate 1.
The outer layer copper foils 3 and 4 have reference holes 10 at their four corners.

P is a prepreg of a desired thickness that is interposed between the outer layer copper foil and the double-sided copper-clad laminate to bond them. Reference numeral 13 is a pressing plate fixed to the lower plate of the heat press, and 14 is a pressing plate fixed to the upper plate of the heat press.

The pressing plates 13 and 14 have reference holes 10 at each of the four corners, through which reference pins 11 fit smoothly. The equipment maker manufactures a multilayer printed wiring board by the pin lamination method. First, as shown in FIG. 5 (A), two double-sided copper-clad laminates 1 and 2 are purchased from the laminate maker. , As shown in FIG. 5 (B), double-sided copper clad laminate 1,
After forming reference holes 10 in each of the four corners of 2, and applying photoresist on both sides, the reference holes of the hard mask are fitted to the reference pins inserted in the reference holes 10, exposed, developed, and etched. Te, and the copper foil 1a of the double-sided copper clad laminate 1 surface to the inner layer circuit L _2, and the back surface of the copper foil 1b with the inner layer circuit L _3, provided IVH18 further plated desired.

Similarly, the copper foil 2a on the surface of the other double-sided copper-clad laminate 2 is used as a desired inner layer circuit L _4, and the copper foil 2b on the back surface is formed.
Is the desired inner layer circuit L ₅ . Next, as shown in FIG. 5 (C), the reference holes 10 are fitted into the reference pins 11, and the outer layer copper foil 4, the desired number of sheets (after being pressed and compressed) are placed on the pressing plate 13. Number of prepregs P, double-sided copper-clad laminate 2, desired number of prepregs P, double-sided copper-clad laminate 1, desired number of prepregs P, outer layer copper foil 3) , The pressing plate 14 is stacked in this order.

Then, heat and pressure are applied by a hot press,
As shown in FIG. 6 (A), after adhesion and curing, the inner layer has inner layer circuits L ₂ , L ₃ , L ₄ , and L ₅ , the outer layer copper foil 3 is adhered to the front surface, and the outer layer copper is attached to the back surface. The printed wiring board is a six-layer printed circuit board on which the foil 4 is attached.

Next, as shown in FIG. 6B, a reference hole is formed.
The reference pin of the hard mask is fitted to the reference pin inserted in 10, and the outer layer copper foil 3 is exposed using the desired mask.
A six-layer multilayer printed wiring board is manufactured by developing and etching to form a desired front surface circuit Ls, and etching the back surface outer layer copper foil 4 to form a desired back surface circuit Lb.

The 8-layer multilayer printed wiring board has three double-sided copper-clad laminates, the 10-layer multilayer printed wiring board has four double-sided copper-clad laminates, and the 12-layer multilayer printed-wiring board has double-sided copper-clad laminates. 5 laminated plates
Each piece is used and manufactured by the pin lamination method according to the above.

[0014]

The pin lamination method has high stacking accuracy as described above, but is not mass-produced. Therefore, when a multilayer printed wiring board having 6 or more layers is manufactured by the pin lamination method as described above, there is a problem that the delivery time becomes long due to the large number of inner layer circuit forming steps.

The present invention was created in view of the above points, and it is an object of the present invention to provide a method for manufacturing a multilayer printed wiring board with a short delivery time.

[0016]

In order to achieve the above object, the present invention provides a core material by providing reference holes 10 in a four-layer printed wiring board manufactured by a mass lamination method as illustrated in FIG. The outer layer copper foils 3 and 4 are laminated on the upper and lower sides of the core material 20 via the prepreg P by a pin lamination method.

Further, as illustrated in FIG. 3, reference holes 10 are provided in a plurality of printed wiring boards of three to four layers manufactured by a mass lamination method as core materials, and prepregs P are provided between the respective core materials. The outer layer copper foil 3 is laminated on the uppermost core material via the prepreg P, and the other outer layer copper foil 4 is laminated on the lowermost core material via the prepreg P by the pin lamination method. The configuration is

Alternatively, as shown in FIG. 4, at least one printed wiring board of three to four layers manufactured by a mass lamination method and at least one printed wiring board having a pattern formed on both sides thereof. Each of the printed wiring boards has a reference hole 10 as a core material, and a prepreg P is interposed between the core materials, and the outer layer copper foil 3 is provided on the uppermost core material via the prepreg P. The other outer layer copper foil 4 is laminated under the core material of the lowermost layer through the prepreg P by the pin lamination method.

[0019]

According to the present invention, the core material has four layers or less in which the inner layer circuit is already formed and laminated by the mass lamination method. Even if the core material of about 4 layers is manufactured by the mass lamination method, the layer displacement between the two inner layer circuit layers in the core material hardly occurs.

The present invention uses such a core material and an outer layer copper foil to manufacture a multilayer printed wiring board having 6 or more layers by a pin lamination method. That is, since the stacking accuracy is high, there is no problem when applied to a multilayer printed wiring board having a small diameter via, IVH, or a fine pattern.

On the other hand, these core materials are used as pin lamination type core materials by patterning the copper foils on the front and back to provide inner layer circuits. Therefore, for example, in the case of a 6-layer multilayer printed wiring board, the inner layer circuit forming process is reduced by 2 inner layers as compared with the conventional method, and in the 10-layer multilayer printed wiring board as compared with the conventional method, the inner layer circuit forming process is reduced. The circuit forming process is reduced by four inner layers. Therefore, the number of steps for forming the inner layer circuit is small and the delivery time is shortened.

Further, since the core material is manufactured by the pin lamination method, it is cheaper than the core material having the same number of layers manufactured by the pin lamination method. Therefore,
The method of the present invention promotes cost reduction of a multilayer printed wiring board.

[0023]

The present invention will be described in detail with reference to the drawings. The same reference numerals denote the same objects throughout the drawings.

1 (A) to 1 (D) are views showing a former stage of the manufacturing process of the embodiment of the present invention, and FIGS. 2 (A) and 2 (B) are latter stages of the manufacturing process of the embodiment of the present invention. 3A and 3B are views of another embodiment of the present invention, and FIGS. 4A and 4B are views of yet another embodiment of the present invention.

In FIGS. 1 and 2, 20 is a four-layer core material manufactured by the mass lamination method. The core material 20 is
The inner layer circuit L ₃ is formed on one surface of the inner insulating layer, and the inner layer circuit L ₄ is formed on the other surface. Then, on the surface of the insulating layer outside the inner layer circuit L ₃ , a copper foil 20a (foil thickness of 35 μm
70 μm) and the copper foil 20b is adhered to the surface of the outer insulating layer of the inner layer circuit L ₄ .

Further, circular reference marks S (marks formed by etching a copper foil) having the same inner diameter as the reference hole 10 are formed at each of four corners of the surface on which the inner layer circuit L ₃ and the inner layer circuit L ₄ are formed. ) Is provided.

Furthermore, an IVH 18 for connecting the inner layer circuit L ₃ and the inner layer circuit L ₄ is provided. 3 and 4 are outer layer copper foils having an outer thickness equal to that of the double-sided copper clad laminate 1 having a foil thickness of about 0.18 μm, and the outer layer copper foils 3 and 4 are provided with reference holes 10 at their four corners. .

P is a prepreg of a desired thickness that is interposed between the outer layer copper foil and the double-sided copper-clad laminate to bond them. Reference numeral 13 is a pressing plate fixed to the lower plate of the heat press, and 14 is a pressing plate fixed to the upper plate of the heat press.

The pressing plates 13 and 14 have reference holes 10 at the four corners, through which the reference pins 11 fit smoothly. Figure 1
As shown in (B), reference holes 10 corresponding to the reference marks S at the four corners of the core material 20 are punched. (The fiducial mark S is formed on the inner layer of the core material 20, but the position of the fiducial mark S can be confirmed from the outside by irradiating X-rays.) Then, after applying photoresist to both surfaces,
The reference pin of the hard mask is fitted to the reference pin inserted into the reference hole 10, exposed, developed, and etched to remove the copper foil 20a on the inner layer circuit L ₃ side as shown in FIG. 1 (C). Inner layer circuit L
_2, and the copper foil 20b on the inner layer circuit L ₄ side is the inner layer circuit L ₅ .

Next, as shown in FIG. 1D, the reference pin
Fit each reference hole 10 to 11, and on the pressing plate 13,
Outer layer copper foil 4, a desired number of prepregs P (the number of which is such that an insulating layer having a desired layer thickness is formed after being pressed and compressed)
The core material 20, the desired number of prepregs P, the outer layer copper foil 3, and the pressing plate 14 are stacked in this order.

Then, heating / pressurization is performed by a hot press,
After bonding and curing, as shown in FIG. 2 (A), the inner layer has inner layer circuits L ₂ , L ₃ , L ₄ and L ₅ , the outer layer copper foil 3 is attached to the front surface, and the outer layer copper is attached to the back surface. The printed wiring board is a six-layer printed circuit board on which the foil 4 is attached.

Next, as shown in FIG. 2 (B), after applying photoresist on both sides, the reference holes of the hard mask are fitted to the reference pins inserted into the reference holes 10 and exposed and developed. , The copper foil 3 for the outer layer is etched to form the surface circuit Ls,
The outer layer copper foil 4 is used as the back surface circuit Lb to form a 6-layer multilayer printed wiring board having a desired circuit.

After that, a via hole, a through hole, etc. are provided and mounting components are mounted. In the method of the present invention, as described above, the core material 20 is purchased from the laminating maker, and then the 6-layer multilayer printed wiring board is manufactured by the pin lamination method. Compared with the manufacturing method, the inner layer circuit forming process performed by the device manufacturer is reduced by two inner layers.

FIG. 3 shows an embodiment of an 8-layer multilayer printed wiring board. In the figure, 30 is a three-layer first core material manufactured by a mass lamination method, and 40 is a three-layer second core material manufactured by a mass lamination method.

In the first core material 30, the inner layer circuit L ₃ is formed in the inner conductor layer, and the copper foil 30a and the copper foil 30 are provided on both front and back surfaces, respectively.
b is attached. Further, circular reference marks S having an inner diameter equal to the inner diameter of the reference hole 10 are provided at each of four corners of the surface on which the inner layer circuit L ₃ is formed.

In the second core member 40, the inner layer circuit L ₆ is formed in the inner conductor layer, and the copper foil 40a and the copper foil 40 are formed on both the front and back surfaces, respectively.
b is attached. Further, circular reference marks S having an inner diameter equal to the inner diameter of the reference hole 10 are provided at each of four corners of the surface on which the inner layer circuit L ₆ is formed.

Reference holes 10 corresponding to the reference marks S are punched at the four corners of each of the first core material 30 and the second core material 40. Then, the copper foil 30a on the surface of the first core member 30 is etched with reference to the reference hole 10 to etch the inner layer circuit L.
_2, and the copper foil 30b on the back side is etched to form the inner layer circuit L ₄
And

Also, the second core material is based on the reference hole 10.
The copper foil 40a on the front surface of 40 is etched to form the inner layer circuit L _5, and the copper foil 40b on the back surface is etched to form the inner layer circuit L ₇ . Next, as shown in FIG. 3 (B), the reference holes 10 are fitted into the reference pins 11, and the outer layer copper foil 4, the desired number of sheets (the desired number after being compressed under pressure, are provided on the pressing plate 13. Number of prepregs P, second core material 40, desired number of prepregs P, first core material 30, desired number of prepregs P, outer layer copper foil 3, The pressing plates 14 are stacked in this order.

Then, heat and pressure are applied by a hot press,
After bonding and curing, the inner layer circuits L ₂ , L ₃ ,
A multilayer printed wiring board having L ₄ , L ₅ , L ₆ , and L ₇ , the outer layer copper foil 3 being adhered to the front surface, and the outer layer copper foil 4 being adhered to the back surface.

After coating the photoresist on both sides, the reference holes of the hard mask are fitted into the reference pins inserted into the reference holes 10, exposed, developed and etched to expose the outer layer copper foil 3 on the surface. The outer layer copper foil 4 is connected to the circuit Ls and the backside circuit Lb is used.
Then, an 8-layer multilayer printed wiring board having a desired circuit is obtained.

FIG. 4 shows an example of a 12-layer multilayer printed wiring board. In the figure, 50 is a four-layer first core material manufactured by a mass lamination method, 60 is a two-layer second core material manufactured by a mass lamination method, and 70 is a four-layer mass layer manufactured by a mass lamination method. It is a third core material.

In the first core material 50, the inner layer circuit L ₃ is formed on one surface of the inner insulating layer, and the inner layer circuit L ₄ is formed on the other surface. Then the copper foil 50a on the surface of the outer insulating layer of the inner layer circuit L ₃ is tensioning copper foil 50b to the surface of the outer insulating layer of the inner layer circuit L ₄ are tensioning.

Further, circular reference marks S (marks formed by etching a copper foil) having the same inner diameter as the reference hole 10 are provided at each of four corners of the surface on which the inner layer circuit L ₃ and the inner layer circuit L ₄ are formed. ) Is provided.

In the third core member 70, the inner layer circuit L ₉ is formed on one surface of the inner insulating layer, and the inner layer circuit L ₁₀ is formed on the other surface. Then, a copper foil 70a is attached to the surface of the outer insulating layer of the inner layer circuit L ₉ , and a copper foil 70b is attached to the surface of the outer insulating layer of the inner layer circuit L ₁₀ .

Further, circular reference marks S equal to the inner diameter of the reference hole 10 are provided at each of four corners of the surface on which the inner layer circuit L ₉ and the inner layer circuit L ₁₀ are formed. First core material 5
0, the reference holes 10 corresponding to the reference marks S at the four corners of the third core material 70 are punched.

Then, the copper foil 50a on the front surface of the first core material 50 is etched to form the inner layer circuit L ₂ and the copper foil 50b on the back surface is etched to form the inner layer circuit L ₅ with reference to the reference hole 10. Further, the inner layer circuit L ₈ and the reference hole 10 by etching the copper foil 70a on the surface of the third core member 70 with respect to the inner layer circuit L ₁₁ the back surface of the copper foil 70b is etched.

On the other hand, the copper foil of the second core material 60 is etched with reference to the reference hole 10, and the inner layer circuit L _{6 is formed on} one surface.
And the inner layer circuit L ₇ is formed on the other surface. Next, Fig. 4 (B)
As shown in FIG. 3, the reference holes 11 are fitted into the reference pins 11, and the outer layer copper foil 4, the desired number of prepregs P, the third core material 70, and the desired number of prepregs are provided on the pressing plate 13. P, the second core material 60, the desired number of prepregs P, the first core material 50, the desired number of prepregs P, the outer layer copper foil 3, and the pressing plate 14 are stacked in this order.

Then, heat and pressure are applied by a hot press,
After bonding and curing, the inner layer circuits L ₂ , L ₃ ,
L _4, has a _{L 5, L 6, L 7} , L 8, L 9, L 10, L 11, outer layer copper foil 3 is tensioning the surface, the outer layer copper foil 4 is tensioning the rear surface Multi-layer printed wiring board.

Then, after coating the photoresist on both sides, the reference holes of the hard mask are fitted to the reference pins inserted into the reference holes 10, exposed, developed and etched to expose the outer layer copper foil 3 on the surface. The outer layer copper foil 4 is connected to the circuit Ls and the backside circuit Lb is used.
Thus, a 12-layer multilayer printed wiring board having a desired circuit is obtained.

[0050]

As described above, according to the present invention, the core material has four layers or less in which the inner layer circuit is already formed and laminated by the mass lamination method, and the copper foils for the outer layers are laminated on the upper and lower sides by the pin lamination method. By doing,
When applied to a multilayer printed wiring board having 6 or more layers having a small-diameter via, IVH, or a fine pattern, it has an effect that layer deviation hardly occurs.

Further, by purchasing the core material from the laminated maker, the manufacturing process of the inner layer circuit of the device maker can be saved, so that the delivery time can be shortened. On the other hand, as a device maker, it is not necessary to purchase a mass-lamination-type manufacturing facility, so that the cost of the multi-layer printed wiring board is reduced by the cost of the mass-lamination-type facility.

[Brief description of drawings]

FIG. 1 (A) to (D) are views showing a former stage of a manufacturing process of an embodiment of the present invention.

2 (A) and 2 (B) are views showing the latter stage of the manufacturing process of the embodiment of the present invention.

3A and 3B are views of another embodiment of the present invention.

4 (A) and (B) are diagrams of still another embodiment of the present invention.

5 (A) to (C) are views showing a former stage of a conventional manufacturing process.

6 (A) and 6 (B) are views showing the latter stage of the conventional manufacturing process.

[Explanation of symbols]

1,2 Double-sided copper clad laminate 1a, 1B, 2a, 2b Copper foil 3,4 Copper foil for outer layer 10 Reference hole 11 Reference pin 13,14 Pressing plate 18 IVH 20 Core material 30,50 First core material 40, 60 second core member 70 third core material P prepreg S reference mark Ls surface circuit Lb backside circuit L ₂ ~L ₁₁ inner layer circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Maruyama Yonezo 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (3)

[Claims] 1. The method of manufacturing by a maslamination method (4)
A reference hole (10) is provided in the printed wiring board of the layer to form a core material (20), and the outer layer copper foils (3, 4) are respectively placed above and below the core material (20) via prepregs (P). A method for manufacturing a multilayer printed wiring board, which comprises laminating the layers by a lamination method. 2. A core material provided with reference holes (10) in a plurality of printed wiring boards of three to four layers manufactured by a maslamination method, and a prepreg (P) is interposed between the core materials, The outer layer copper foil (3) is placed on the uppermost core material through another prepreg (P), and the outer copper foil (3) is placed under the lowermost core material through another prepreg (P). A method for manufacturing a multilayer printed wiring board, characterized in that 4) is laminated by a pin lamination method. 3. A printed wiring board having at least one three-layer to four-layer printed board manufactured by a maslamination method and at least one printed wiring board having a pattern formed on both surfaces thereof. A plate is provided with reference holes (10) as core materials, prepregs (P) are interposed between the respective core materials, and an outer layer copper foil is provided on the uppermost core material through another prepreg (P). A multilayer printed wiring board characterized in that (3) is laminated with another outer layer copper foil (4) under the core material of the lowermost layer through another prepreg (P) by a pin lamination method. Method.