Preparation method for HDI rigid-flex PCB interlayer blind hole all-copper filling

A rigid-flex board, copper filling technology, applied in the direction of printed circuit manufacturing, processing step sequence, printed circuit, etc., can solve the problem of improving the difficulty of full copper filling of rigid-flex board, hindering the development of HDI rigid-flex board, and filling potions. It is difficult to reach the bottom of the hole and other problems, so as to save the production cost and production time, improve the production efficiency and production efficiency, and improve the thermal conductivity.

Inactive Publication Date: 2016-02-03
AKM ELECTRONICS TECH SUZHOU
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AI Technical Summary

Problems solved by technology

[0009] However, the full copper filling of interlayer blind holes in HDI rigid-flex boards has not yet been published in relevant reports, because the interlayer blind holes in HDI rigid-flex boards are distributed in rigid areas, flexible areas, and rigid-flex areas. The full copper filling of blind holes has different difficulties, especially in the rigid-flex joint area
In the rigid-flexible area, the blind holes have different media (usually containing FR4, PI and adhesives and other media), and the blind holes are mostly laser drilled, while metal copper, FR4, PI, and adhesives are not suitable for laser drilling. The hot-melt characteristics of the two are different, so the hole type is complex, and the roughness of the hole wall is very different. At the same time, because the thickness of the rigid zone is usually re...

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  • Preparation method for HDI rigid-flex PCB interlayer blind hole all-copper filling
  • Preparation method for HDI rigid-flex PCB interlayer blind hole all-copper filling

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Embodiment 1

[0036] see figure 1 and 2 , a full copper filling of blind holes between HDI rigid-flex boards, prepared according to the following steps:

[0037] 1) Prepare a double-sided copper-clad laminate, with copper foil with a thickness of 18 μm on the upper and lower surfaces, and a thickness of the interposer layer of 75 μm. Apply a dry film to one side of the double-sided copper-clad laminate, and use a horizontal copper-reducing wire to reduce copper on one side on the side without the dry film. The thickness of the copper foil on the copper-reducing side is 7 μm.

[0038] 2) Use CAD software to make the drilling data of the blind holes between the HDI rigid-flex boards, and use UV laser drilling to drill the copper-reducing side of the double-sided copper-clad laminate according to the drilling data, and the shape of the prepared blind holes It is an inverted trapezoid, A is the upper aperture of the blind hole of the HDI rigid-flexible board, and B is the lower aperture of th...

Embodiment 2

[0043] The steps of this embodiment are basically the same as those of Embodiment 1, the difference is that in step 5), the components of the electroplating potion used for hole filling copper plating include 220g / L of copper sulfate pentahydrate, 50g / L of sulfuric acid, 50ppm of chloride ions, accelerated agent 1.0mL / L), inhibitor 15mL / L, leveling agent 15mL / L, the blind hole is filled and leveled after electroplating, and the line is leveled.

Embodiment 3

[0045] The steps of this embodiment are basically the same as those of Embodiment 1, the difference is that in step 5), the components of the electroplating potion used for hole filling copper plating include 240g / L of copper sulfate pentahydrate, 60g / L of sulfuric acid, 60ppm of chloride ions, accelerated The agent is 1.2mL / L, the inhibitor is 18mL / L, and the leveling agent is 18mL / L. After electroplating, the blind hole is filled and leveled, and the line is leveled.

[0046]A preparation method for full copper filling of blind holes between layers of HDI rigid-flexible boards in the above embodiment uses a horizontal copper reduction wire to reduce copper on one side of a double-sided copper clad laminate, and uses a UV laser to drill blind holes on the copper-reducing side. Then remove the glue, sink copper, and finally use the blind hole electroplating process to fill the blind hole with copper, so that the rigid-flexible board reaches the interlayer interconnection, savin...

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Abstract

The invention provides a preparation method for HDI rigid-flex PCB interlayer blind hole all-copper filling, comprising the following steps: (1) preparing a double-sided copper-clad board and reducing copper on one side of the double-sided copper-clad board; (2) preparing an inverted trapezoidal blind hole in the copper-reduced side of the double-sided copper-clad board through laser drilling; (3) cleaning the wall and bottom of the blind hole and removing residue left on the wall and bottom during hole drilling; (4) depositing a metal copper layer on the surface of the wall and bottom of the blind hole; and (5) filling the blind hole deposited with the metal copper layer with copper to realize interlayer interconnection of the HDI rigid-flex PCB. Compared with the prior art, HDI rigid-flex PCB interlayer blind hole all-copper filling is realized, the interlayer connectivity of the blind hole is ensured, the wiring density of the HDI rigid-flex PCB is improved, the cost of equipment investment is reduced, and the production efficiency and production benefit are improved.

Description

technical field [0001] The invention relates to the technical field of HDI rigid-flex boards, in particular to a preparation method for filling blind holes between layers of HDI rigid-flex boards with full copper. Background technique [0002] With the increasing integration of electronic devices, especially the continuous development of wearable devices, higher requirements are put forward for HDI rigid-flex boards. HDI rigid-flex board refers to a printed circuit board with one or more rigid regions and one or more flexible regions, and the rigid-flex regions can be interconnected arbitrarily. To realize any interlayer interconnection in the HDI rigid-flex board, the HDI rigid-flex board must contain blind holes, so the preparation and filling of blind holes between HDI rigid-flex boards is one of the most critical steps. At present, the filling of blind holes between layers of HDI rigid-flex boards uses CO 2 Laser drilling, then copper sinking, copper plating, and final...

Claims

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Application Information

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IPC IPC(8): H05K3/42
CPCH05K3/421H05K3/361H05K1/147H05K2203/0353H05K3/0035H05K2201/09563H05K3/42H05K3/36H05K1/0298H05K1/115H05K3/4623H05K2203/14
Inventor 周江涛
Owner AKM ELECTRONICS TECH SUZHOU
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