JP2809526B2 - Method of manufacturing multilayer blind through-hole wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a multilayer blind through-hole wiring board, and more particularly to a method of accurately drilling a reference hole when drilling an outer layer.

[0002]

2. Description of the Related Art A reference hole at the time of drilling an outer layer of a multilayer blind through-hole wiring board is used as a coordinate reference for a wiring pattern. This is for obtaining alignment and obtaining alignment between the inner layer through hole (blind through hole) and the pattern or land of the outer layer. More specifically, the dimensional accuracy of the multilayer board not only suppresses dimensional changes in various processing steps, but also reduces the relative error between wiring patterns of each layer, or through holes, outer layer patterns, resist patterns, etc. Can only be obtained. The reference hole is the origin for creating this relative positional relationship. Multi-layer board as shown in FIG.
The reference holes 21 in 20 are usually provided at at least two places outside the wiring pattern 22 in the inner layer. As an arrangement method, a target called a register mark 23 is provided at a position separated by a predetermined coordinate from the inner layer pattern 22 as shown in FIG. 13, and as shown in FIG. 14, the multilayer plate 20 is laminated and formed by an end mill. The register mark 23 is exposed (spotted) 24 by cutting. And the exposed register mark
Drill a reference hole 21 of the specified diameter aiming at 23.

In a multilayer blind through-hole wiring board, when a reference hole 21 is made by using a register mark 23, the pattern of the middle layer is aimed at, and the gap between the blind through hole and the land of the outer layer is easily generated.

[0004] Therefore, a hole which becomes a large reference hole at the time of drilling the inner layer is also formed, and the hole is used as a reference hole at the time of drilling the outer layer. A method for manufacturing a multilayer blind through-hole wiring board in which a multilayer blind through-hole having no misalignment as a whole is formed when the inner layer pattern is manufactured and the outer layer pattern is manufactured in alignment with the holes in both cases is considered.

[0005] However, if a hole is formed before lamination molding of a multilayer board, the prepreg resin oozes out after molding through the hole, and the contour of the hole serving as the pilot hole of the reference hole is blurred. Therefore, the prepreg resin exuded before drilling the reference hole is scraped to make the contour clear, but if it is a little unclear, if the reference hole is automatically drilled by the multilayer drilling machine for multilayer boards The reference hole is shifted.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention is intended to eliminate the bleeding of the prepreg resin from the reference hole on the lowermost layer surface when laminated and formed on a multilayer board, and to improve the reference hole after lamination. It is an object of the present invention to provide a method for manufacturing a multilayer blind through-hole wiring board capable of accurately and quickly drilling holes.

[0007]

According to the present invention, there is provided a method for manufacturing a multilayer blind through-hole wiring board according to the present invention, comprising the steps of: forming a through-hole and a reference hole in a copper-clad laminate for an inner layer material; Apply through-hole plating, then form an inner layer circuit by etching, then treat the inner layer copper surface, then close the reference hole on the upper layer surface from the lowermost layer surface with heat resistant tape and lay up A multilayer board is formed by laminating and molding the required layer, then a reference hole is drilled in the multilayer board using the reference hole on the lowermost layer surface as a pilot hole, and then a through hole is drilled in the multilayer board. An outer layer circuit is formed by plating, followed by etching, followed by solder resist printing, followed by symbol printing, then external processing and surface treatment.

[0008]

As described above, in the method of manufacturing a multilayer blind through-hole wiring board according to the present invention, before forming the inner layer circuit, treating the inner layer copper surface, and forming the laminate, the layer surface higher than the lowermost layer surface to be laminated is formed. After the reference hole is closed with heat-resistant tape, it is laid up, so that the prepreg resin does not ooze into the reference hole on the lowermost layer during lamination. When drilling a reference hole with the hole as a pilot hole, it is not necessary to remove the exuded prepreg resin as in the past, and the ring around the periphery of the reference hole is clear, so that the reference hole is accurately and quickly drilled. Can be.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the method for manufacturing a multilayer blind through-hole wiring board according to the present invention will be described with reference to the drawings. FIG. 1 shows a glass epoxy board 1 shown in FIG. After drilling holes 4 for through holes at the circuit forming portion and holes 5 for reference outside the frame of the circuit forming portion on the copper-clad laminate 3 as shown in FIG. 2, electroless copper plating as shown in FIG. Alternatively, through-hole plating 6 was applied by a panel electrolytic copper plating method, then an inner layer circuit 7 was formed by etching as shown in FIG. 4, and then an inner layer copper surface treatment (blackening treatment) was performed. Up to this point, it is the same as the conventional manufacturing method.

Next, a laminated plate 8 having a fifth layer surface, which is higher than the lowermost layer surface to be laminated into six layers in this embodiment, is provided.
After closing the reference hole 5 of FIG. 5 with a heat-resistant tape cut into a 10 mm × 10 mm square as shown in FIG. 5, in this example, a Kapton tape 9,
Layed up. Next, as shown in FIG.
The laminated plates 11 and 11 having the inner layer circuit 7 formed therebetween and the laminated plate 8 in which the reference holes 5 are closed with a Kapton tape 9 are polymerized and laminated and formed by a press and heat press to form a six-layer plate 12. did. Next, a reference hole 13 was formed in the six-layer plate 12 as shown in FIG. 7 using the reference hole 5 on the lowermost layer surface as a prepared hole.

The subsequent steps are the same as the conventional manufacturing method. That is, as shown in FIG. 8, through holes 14 are formed in the six-layer plate 12, and then through hole plating 15 is performed by an electroless copper plating method or a panel plating method as shown in FIG. The outer layer circuit 16 is formed as shown in the figure, then the solder resist printing 17 is performed as shown in FIG. 11, and then the symbol printing (not shown) is performed. Thereafter, the outer shape processing is performed, and the surface treatment such as flux application is performed. As a result, a six-layer blind through-hole wiring board was obtained.

When a six-layer type blind through-hole wiring board is manufactured in this manner, the reference holes 5 of the conventional laminated board 8 having the fifth layer surface are not closed with the Kapton tape 9.
It took 30 seconds to remove the prepreg resin oozing out on the sixth layer surface and to make a reference hole, but this was reduced to 8 seconds. In addition, in the conventional drilling of the reference hole, there was a variation of ± 15 μm or more, but it became ± 10 μm or less, and the variation of the reference hole 13 was reduced.

[0013]

As can be seen from the above description, according to the method for manufacturing a multilayer blind through-hole wiring board of the present invention, the prepreg resin oozes out into the reference holes in the lowermost layer surface when the multilayer board is formed by lamination. There is no need to remove the exuded prepreg resin as in the past when drilling a reference hole in a multilayer board obtained by lamination molding with the reference hole as a pilot hole. Because the ring is clear, the reference hole can be drilled accurately and quickly. Therefore, a multilayer blind through-hole wiring board can be manufactured efficiently, and the displacement between the inner through-hole (blind through-hole) and the outer-layer rotation can be eliminated.

[Brief description of the drawings]

FIG. 1 is a view showing the steps of one embodiment of a method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 2 is a diagram showing the steps of one embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 3 is a view showing the steps of an embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 4 is a diagram showing the steps of one embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 5 is a diagram showing the steps of an embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 6 is a diagram showing the steps of one embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 7 is a view showing the steps of one embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 8 is a diagram showing the steps of one embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 9 is a view showing the steps of one embodiment of the method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 10 is a view showing a step of one embodiment of a method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 11 is a view showing a step of one embodiment of a method for manufacturing a multilayer blind through-hole wiring board of the present invention.

FIG. 12 is a diagram showing reference holes in a multilayer board.

FIG. 13 is a view showing a register mark conventionally provided in an inner layer for providing a reference hole.

FIG. 14 is a diagram illustrating a conventional method for drilling a reference hole.

[Explanation of symbols]

 3 Copper clad laminate for inner layer material 4 Hole for through hole 5 Reference hole 6 Through hole plating 7 Inner layer circuit 9 Heat resistant tape (Kapton tape) 12 Multilayer board (6 layer board) 13 Reference hole 14 Hole for through hole 15 Through hole plating 16 Outer layer circuit 17 Solder resist printing

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05K 3/46

Claims (1)

(57) [Claims] 1. A through-hole and a reference hole are formed in a copper-clad laminate for an inner layer material, and then through-hole plating is performed. Then, an inner layer circuit is formed by etching, then an inner layer copper surface treatment is performed, and then a laminate is formed. After closing the reference hole on the layer surface higher than the lowermost layer surface with heat-resistant tape, lay it up and laminate-mold it to the required layer to form a multilayer board. Then, the reference hole on the lowermost layer surface is formed on the multilayer board. A reference hole is drilled as a pilot hole, then an outer layer circuit is formed by etching, then symbol printing is performed after solder resist printing, then outer shape processing is performed, and then a multilayer blind through hole for surface treatment Manufacturing method of wiring board.