JP3649109B2 - Multilayer printed wiring board and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer printed wiring board used for electronic equipment and the like.
[0002]
[Prior art]
In recent years, multilayer printed wiring boards used for electronic devices and the like are required to have high reliability as well as high density.
[0003]
A conventional multilayer printed wiring board will be described below.
[0004]
FIG. 5 is a cross-sectional view showing a configuration of a conventional multilayer printed wiring board.
[0005]
In FIG. 5, 1 is an inner layer base material, 2a and 2c are inner layer circuit patterns, 3 is an outer layer base material, 4a and 4c are outer layer circuit patterns, 5 is a solder resist, and 6 is an outer shape desired in a later process. Forming edges 2b and 2d of the inner layer circuit patterns 2a and 2c are formed at the boundary lines scheduled for cutting of the outer shape processing, that is, forming ends of the outer shape processing and on the inner and lower sides of the forming ends 4b and 4d of the outer layer circuit patterns 4a and 4c. .
[0006]
Conventionally, when an earth pattern with a wide circuit width is formed near the edge of the outer shape forming, the inner layer circuit pattern may be exposed from the wall of the outer shape forming in order to design the circuit as much as possible, or due to misalignment when the inner layers are stacked In many cases, the above-mentioned positional relationship is obtained in order to lower the value.
[0007]
Furthermore, since the relationship and problems between the above-mentioned positional relationship and outline processing have not been grasped, the circuit design technology can be used without mentioning the positional relationship between the formation end of the outline processing and the formation ends of the circuit patterns of the inner layer and the outer layer. The current situation is to leave it to the discretion of the person.
[0008]
Hereinafter, the background of the inventor of the present invention grasping the problems in the external shape processing of the above-described conventional multilayer printed wiring board will be described below.
[0009]
First, FIG. 6 (a) shows a configuration at the time of outer shape processing, where 7 is an outer die of an upper die, 8 is a stripper plate of an upper die, 9 is a die of a lower die, and 10 is a lower die. External stripper plate.
[0010]
Next, the outer shape processing of the multilayer printed wiring board will be described.
[0011]
FIG. 6B shows the moment when the upper die is lowered onto the multilayer printed wiring board 0 installed on the lower die and the outer shape is processed.
[0012]
When the multilayer printed wiring board 0 is cut on the outer shape cutting line 6, the upper mold stripper plate 8 comes into contact with the multilayer printed wiring board 0 and stops.
[0013]
Next, the outer die 7 of the upper mold is lowered.
[0014]
At this time, a shearing force and a bending moment are generated on the outer shape cutting line 6 of the multilayer printed wiring board 0 by the lower die 9 and the upper die 7.
[0015]
Since the bending moment is fixed by the upper mold stripper plate 8 and the lower mold die 9, and the upper mold outer die 7 and the lower mold outer stripper plate 10, the outer shape is processed into a desired shape by a shearing force. I do.
[0016]
At this time, a bending moment is also generated in the vicinity of the contour processing cutting line 6 and extends from the contour processing cutting line 6 to the inside of the multilayer printed wiring board 0.
[0017]
[Problems to be solved by the invention]
However, in the above-described outer shape processing of the multilayer printed wiring board 0, the upper die is lowered onto the outer shape cutting line 6 and then cut into a desired outer shape by a shearing force with the lower die. The bending moment generated at the same time reaches the inner side of the multilayer printed wiring board 0, and the maximum bending occurs on the tangent line of the end portions 2b and 2d of the inner layer circuit patterns 2a and 2c formed on the inner lower side of the outer layer circuit pattern 4a. Occurs, the solder resist 5 peels off the outer circuit pattern 4a, and the process yield deteriorates.
[0018]
Furthermore, in a recent build-up type high-density multilayer printed wiring board having a small-diameter conduction hole of 100 μm, the conduction hole and outermost layer near the outer edge of the outer shape processing are affected by the impact of the shearing force and the bending moment during the outer shape processing. This has the possibility of causing cracks in the insulating resin layer, and has the possibility of impairing the reliability of the multilayer printed wiring board.
[0019]
The present invention solves the above-mentioned conventional problems, and after external processing of a printed wiring board, the solder resist is peeled off on the external processing cutting line and in the vicinity thereof, or the conductive hole and the outermost insulating resin in the vicinity of the external processing forming end. The purpose is to reduce the possibility of cracks in the layer, to improve the process yield and to stabilize the quality.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, the present invention manufactures a multilayer printed wiring board formed so that the inner layer pattern forming end of the multilayer printed wiring board is positioned between the outer layer pattern forming end and the outer shape forming end. In other words, the outer shape is processed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Invention of Claim 1 of this invention was formed on the insulating base material laminated | stacked on the printed wiring board for inner layers which has the inner layer pattern formed in the insulating base material for inner layers, and the printed wiring board for inner layers An outer layer pattern, a solder resist formed on the outer layer pattern, and an outer shape forming end formed by press punching, and the inner layer pattern forming end is between the outer layer pattern forming end and the outer shape forming end. It is a multilayer printed wiring board characterized in that it is formed at a position, and the outer shape processing of the multilayer printed wiring board solves the conventional problem when press punching using a mold, The printed configuration is a multilayer printed wiring board formed so that the inner layer pattern forming end is positioned between the outer layer pattern forming end and the outer shape forming end. .
[0022]
As a result, when the multilayer printed wiring board installed on the lower mold is cut on the outer shape processing line by the lowering of the upper mold, the impact and bending during shearing caused by the outer die of the upper mold and the die of the lower mold are bent. Moments can be absorbed and relaxed at the formation edge of the inner layer pattern.
[0023]
This action can reduce the bending of the outer layer pattern and the insulating base material, thus eliminating the peeling of the solder resist on the outer layer pattern and minimizing the damage caused by the impact of the insulating base material in the vicinity of the outer shape forming end. To the limit.
[0024]
In particular, by forming the end of the inner layer pattern so that it is located at the midpoint between the end of the outer layer pattern and the end of the outer shape processing, it is possible to stack and align the inner layer substrate in the multilayer printed wiring board manufacturing process. In this case, even if a position shift occurs in the direction of the outer shape processing formation edge, the inner layer pattern formation end is not exposed from the outer shape processing formation wall surface. It can be absorbed and relaxed sufficiently.
[0025]
In addition, in printed wiring boards where the insulating base material is flexible and the bending moment during shearing is easily affected, and in printed wiring boards using non-woven fabric base resin laminates as insulating substrates, the fluff on the processed wall surface This is effective in reducing the occurrence of fiber burrs.
[0026]
According to a second aspect of the present invention, the insulating base material laminated on the printed wiring board for the inner layer includes a conduction hole filled with a conductive material, and the inner layer pattern and the outer layer pattern are electrically connected through the conduction hole. The multilayer printed wiring board according to claim 1, wherein the multilayer printed wiring board according to claim 1 is electrically connected by filling and curing a conductive material in a small diameter conduction hole of an outer layer and an inner layer. It is necessary to minimize the influence of the impact and bending moment on the insulating substrate during external processing, and the above-described configuration of the present invention works particularly effectively in securing the connection reliability of the conduction hole.
[0027]
The invention according to claim 3 of the present invention includes a step of preparing an inner layer printed wiring board in which an inner layer pattern is formed on an inner layer insulating base material, and an insulating base material is laminated on the inner layer printed wiring board, A step of forming an outer layer pattern, a step of forming a solder resist on the outer layer pattern, and a step of forming an outer shape by forming an outer shape by press punching, wherein the inner layer pattern forming end is an outer layer pattern forming end. A multilayer printed wiring board manufacturing method characterized in that a circuit is designed and formed so as to be positioned between the outer edge and the outer shape forming end, and the multilayer printed wiring board is manufactured using this manufacturing method. Thus, it is possible to solve the conventional problems when the outer shape of the multilayer printed wiring board is press punching using a mold.
[0028]
That is, when a multilayer printed wiring board installed on the lower mold is cut on the outer shape processing line by lowering the upper mold, the impact and bending moment during shearing generated by the outer die of the upper mold and the die of the lower mold Can be absorbed and relaxed at the end of the inner layer pattern.
[0029]
As a result, the bending of the outer layer pattern and the insulating base material can be reduced, so that the peeling of the solder resist on the outer layer pattern can be eliminated, and the damage due to the impact of the insulating base material near the outer shape forming formation edge is minimized. A multilayer printed wiring board that can be suppressed to the limit can be provided.
[0030]
(Embodiment 1)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0031]
FIG. 1 shows a multilayer printed wiring board according to an embodiment of the present invention, and FIG. 2 shows a method for manufacturing a multilayer printed wiring board according to an embodiment of the present invention. 1 and 2, 11 is a multilayer printed wiring board, 12a and 12c are inner layer patterns, 12b and 12d are inner layer pattern forming ends, 13a and 13c are outer layer patterns, 13b and 13d are outer layer pattern forming ends, and 14 is an outer layer pattern forming end. Solder resist, 15a to 15d are through holes, 16 is a conductive material, 17 is a forming end of outer shape processing, 18a to 18c is an insulating base, 19 is copper foil, 20 is a printed wiring board for inner layers, 21 is a film, 22 Is an outline processing line.
[0032]
The manufacturing method of the multilayer printed wiring board configured as described above will be described with reference to FIG. 1 and FIG.
[0033]
First, as shown in FIG. 2 (a), a film 21 made of a polyester resin is vacuum-laminated on both surfaces of a prepreg constituting a semi-cured insulating base material 18a impregnated with plastic aramid nonwoven fabric, A through hole 15a having a predetermined diameter is formed by means such as a laser beam such as gas or excimer.
[0034]
Next, the conductive material 16 is filled or applied to the through holes 15a formed in the insulating base material 18a and the film 21 by means of a screen printing method or the like, and then the film 21 is formed as shown in FIG. Peeling and removing are performed to prepare a plurality of insulating base materials 18a.
[0035]
Further, after vacuum laminating films on both surfaces of the prepreg constituting the insulating base material 18b, through holes 15b and 15c having a predetermined diameter are formed, and the conductive material 16 is filled or applied to the through holes 15b and 15c, and then the film is formed. Is peeled and removed to form the insulating base material 18b for the inner layer.
[0036]
Next, the copper foil 19 is laminated on both surfaces of the insulating base material 18b for the inner layer as shown in FIG.
[0037]
Next, an etching resist is formed on the surface of the laminated copper foil 19 using a photographic developing method or the like.
[0038]
Further, the exposed copper foil on the surface where the etching resist is not formed is removed by etching with a solution such as cupric chloride, and the etching resist is peeled off, so that the insulating group for the inner layer is removed as shown in FIG. Inner layer patterns 12a and 12c are formed on the material 18b.
[0039]
The circuit is designed in advance so that the inner layer pattern forming ends 12b and 12d are located between the outer layer pattern forming ends 13b and 13d and the outer shape processing line 22, and these are laminated.
[0040]
Further, in a multilayer structure, the inner layer pattern 12a immediately under the outer shape processing is used as a ground layer and the other inner layer pattern 12c is used as a power supply layer in advance to design the circuit, and the formation end 12b of the inner layer pattern 12a is formed by the inner layer pattern 12c. An inner layer printed wiring board 20 formed so as to be closer to the outer shape processing line 22 than the forming end 12d is obtained.
[0041]
Next, the outer layer insulating base material 18a, the inner layer printed wiring board 20, the outer layer insulating base material 18c, and the copper foil 19 are combined with the copper foil 19 and the conductive material 16 filled or applied in the through holes 15a. Then, it laminates | stacks, heating and pressurizing with a vacuum hot press machine, and forms a copper clad multilayer insulation board | substrate as shown in FIG.2 (e).
[0042]
Further, after forming an etching resist for the outer layer on the copper foil 19 of the copper clad multilayer insulating substrate using a photographic development method, the exposed copper on the surface where the etching resist is not formed by a solution of cupric chloride or the like. The foil 19 is removed by etching, and the etching resist is peeled off to form the outer layer patterns 13a and 13c.
[0043]
Next, a solder resist 14 is formed by using a method such as a screen printing method or a photographic development method. As shown in FIG. 2 (f), the solder resist 14 is positioned between the outer layer pattern forming ends 13b and 13d and the outer shape processing line 22. The multilayer printed wiring board 11 formed by the inner layer pattern forming ends 12b and 12d and the through holes 15a, 15b, 15c and 15d filled or coated with the conductor 16 is obtained.
[0044]
In addition, although said through-hole 15a, 15b, 15c, and 15d filled the electrically conductive material and formed the conduction hole, you may form by electroplating.
[0045]
The outline processing steps in the multilayer printed wiring board will be described with reference to FIGS. 3 (a) and 3 (b).
[0046]
FIG. 3 (a) shows a configuration at the time of outer shape processing, wherein 51 is an outer die of an upper die, 52 is a stripper plate of an upper die, 53 is an outer die of a lower die, and 54 is a lower die. , An outer shape stripper plate, 22 an outer shape processing line, 56 a shearing force, 57 a bending moment, and 11 a multilayer printed wiring board.
[0047]
Next, the outer shape processing of the above multilayer printed wiring board will be described below.
[0048]
FIG. 3 (b) shows the moment when the upper die is lowered onto the multilayer printed wiring board installed on the lower die and the outer shape is processed.
[0049]
When the multilayer printed wiring board 11 is cut on the outer shape processing line 22, the upper mold stripper plate 52 comes into contact with the multilayer printed wiring board and stops.
[0050]
Next, the outer die 51 of the upper mold is lowered. At this time, the shearing force 56 and the bending moment 57 generated on and near the outer shape processing line 22 of the printed wiring board by the lower die 51 and the upper die 51 are the formation of the inner-layer conductor patterns 12a and 12c. Due to the presence of the ends 12b and 12d, it is possible to absorb and mitigate the impact and bending moment during the outer shape processing.
[0051]
Further, by forming the formation ends 12b and 12d of the inner layer conductor patterns 12a and 12c and the formation ends 13b and 13d of the outer layer conductor patterns 13a and 13c, it is possible to prevent concentration of impact force stress due to the outer shape processing shape. Can do.
[0052]
Further, one of the formation ends 12b and 12d of the inner layer conductor patterns 12a and 12c is formed so as to be positioned at the midpoint between the formation ends 13b and 13d of the outer layer conductor patterns 13a and 13c and the outer shape processing line 22. As a result, even when misalignment occurs during the stacking / positioning of the inner layer substrate in the manufacturing process of the multilayer printed wiring board, it is possible to sufficiently absorb and alleviate the impact and bending during the outer shape processing.
[0053]
Furthermore, the formation end 13d of the outer layer conductor pattern 13c on the opposite side of the punching surface is formed closer to the outer shape processing line 22 than the formation end 12c of the outer layer conductor pattern 12a on the press punching surface side. The impact and bending moment at the time of outer shape processing shearing can be absorbed and alleviated also at the formation ends 13b and 13d of the outer layer conductor patterns 13a and 13c.
[0054]
By adopting the multilayer printed wiring board having the above-described configuration, it is possible to eliminate the peeling of the solder resist in the vicinity of the outer shape forming end, and to reduce the possibility of occurrence of cracks in the through-conduction holes.
[0055]
Further, in the present embodiment, an example of a four-layer multilayer printed wiring board having a through conduction hole filled with a conductive material has been shown. As an application of this example, a build-up type multilayer printed wiring in which an insulating resin layer is applied and formed on the outermost layer of the four-layer multilayer printed wiring board, a non-through hole is provided in the insulating resin layer, and metal plating is applied thereto. The present invention is also effective for plates.
[0056]
In this case, the possibility of occurrence of cracks in the insulating resin layer can be reduced in addition to the above-described solder resist and conduction holes.
[0057]
(Embodiment 2)
Hereinafter, another embodiment of the present invention will be described with reference to the drawings.
[0058]
4A shows a perspective view of the printed wiring board for the inner layer in the multilayer printed wiring board according to the second embodiment, and FIG. 4B shows the printed wiring board for the inner layer shown in FIG. It is a block diagram of the used multilayer printed wiring board.
[0059]
In FIG. 4A, reference numerals 71 to 74 are independent circuits.
[0060]
As shown to Fig.4 (a), in the manufacturing method of the multilayer printed wiring board in Embodiment 2, when forming the printed wiring board for inner layers, several independent circuits 71-74 are formed.
[0061]
In FIG. 4B, 80 to 83 are inner layer conductor patterns, and 84 is an outer shape processing line.
[0062]
As described in the first embodiment, the multilayer printed wiring board having a plurality of inner layers has a design restriction if the inner-layer conductor pattern immediately below the outer-layer circuit pattern is a ground layer and the other one is a power supply layer. There is a case.
[0063]
However, as shown in FIG. 4B, by forming at least one independent circuit on the side of the outer shape processing line 84, the inner layer conductor pattern 80 directly under the outer shape processing is the ground layer, 81 is the power supply layer, and the other one. The inner layer conductor pattern 82 is formed as a power supply layer and 83 is used as a ground layer, so that the circuit design can be performed without being restricted by the arrangement of the power supply layer and the ground layer and the design of the wiring pattern.
[0064]
Furthermore, by forming an independent circuit that is not electrically connected to other independent circuits on the outer shape processing line 84 side, the impact and bending moment absorption and relaxation during the outer shape processing are partially and locally enhanced. This has the same effect as shown in the first embodiment.
[0065]
【The invention's effect】
As described above, the present invention can reduce the bending of the outer layer pattern and the insulating substrate when the outer shape processing of the multilayer printed wiring board is a press punching process using a die, and therefore, the solder resist on the outer layer pattern can be reduced. While peeling can be eliminated, cracks and breakage due to impact on the insulating base material, the insulating resin layer, and the conduction hole in the vicinity of the outer shape forming end can be minimized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a multilayer printed wiring board according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the multilayer printed wiring board in the manufacturing process. Cross-sectional view installed above (b) Cross-sectional view at the moment when the multilayer printed wiring board is externally cut. FIG. 4 (a) A perspective view of the printed wiring board for the inner layer in the multilayer printed wiring board according to Embodiment 2 of the present invention. Fig. (B) Configuration of multilayer printed wiring board using the same inner layer printed wiring board [Fig. 5] Sectional view showing the configuration of a conventional multilayer printed wiring board [Fig. 6] (a) A conventional multilayer printed wiring board Cross-sectional view installed on the lower mold (b) Cross-sectional view at the moment of external cutting of a conventional multilayer printed wiring board [Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Multilayer printed wiring board 12a, 12c Inner layer conductor pattern 12b, 12d Inner layer conductor pattern formation end 13a, 13c Outer layer conductor pattern 13b, 13d Outer layer conductor pattern formation end 14 Solder resist 15a-15d Through-hole 16 Conductor 17 Formed end of outer shape processing 18a to 18c Insulating base material 19 Copper foil 20 Printed wiring board for inner layer 21 Film 22, 84 Outer shape processing line 51 Upper die outer die 52 Upper die stripper plate 53 Lower die outer shape Die 54 Outer stripper plate of lower mold 56 Shear force 57 Bending moment 71-74 Independent circuit 80-83 Conductor pattern for inner layer

Claims (3)

  Inner layer printed wiring board having inner layer pattern formed on inner layer insulating base material, outer layer pattern formed on insulating base material laminated on inner layer printed wiring board, and solder formed on outer layer pattern A multi-layered structure comprising a resist and an outer shape forming end formed by press punching, wherein the inner layer pattern forming end is formed between the outer layer pattern forming end and the outer shape forming end. Printed wiring board.   The insulating base material laminated on the printed wiring board for inner layer is provided with a conduction hole filled with a conductive material, and the inner layer pattern and the outer layer pattern are electrically connected through the conduction hole. A multilayer printed wiring board according to 1.   A step of preparing an inner layer printed wiring board having an inner layer pattern formed on the inner layer insulating base material, a step of laminating the insulating base material on the inner layer printed wiring board and forming an outer layer pattern thereon, and an outer layer pattern on the inner layer pattern A step of forming a solder resist and a step of forming an outer shape by forming an outer shape by press punching, the inner layer pattern forming end being positioned between the outer layer pattern forming end and the outer shape processing forming end A method for producing a multilayer printed wiring board, wherein the circuit is designed and formed.

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