Double-sided copper foil circuit board structure and manufacturing method thereof

Abstract

A method for manufacturing a circuit board structure with double-sided copper foil includes: providing a printed circuit board with its upper and lower surfaces covered by a surface copper layer; forming a protective layer on the surface copper layer; drilling to form a first through-hole, wherein a first inner sidewall of the printed circuit board is exposed through the first through-hole; forming a first copper foil layer on the first inner sidewall; removing a portion of the first copper foil layer and the protective layer, such that the first surface of the exposed first copper foil layer is flush with the second surface of the exposed surface copper layer; drilling to form a second through-hole, wherein a second inner sidewall of the printed circuit board is exposed through the second through-hole; and forming a second copper foil layer on the second inner sidewall of the printed circuit board and the surface copper layer, wherein the copper plating thickness above the upper surface of the printed circuit board is the same as the copper plating thickness above the lower surface.

Claims

1. A method for manufacturing a circuit board structure with double-sided copper foil, comprising: A printed circuit board (110) is provided, wherein the printed circuit board (110) has an upper surface (112) and a lower surface (114) opposite to the upper surface (112), and the upper surface (112) and the lower surface (114) are covered by a surface copper layer (120); a protective layer (130) is formed on the surface copper layer (120), wherein the protective layer (130) completely covers the surface copper layer (120); a first drilling process is performed on the protective layer (130), the surface copper layer (120) and the printed circuit board (110) to form a first through hole (T1), wherein a first inner sidewall (116) of the printed circuit board (110) is exposed from the first through hole (T1); A first copper foil layer (140) is formed on the protective layer (130), the surface copper layer (120) exposed from the first through hole (T1), and the first inner sidewall (116) of the printed circuit board (110); a portion of the first copper foil layer (140) and the protective layer (130) is removed, such that a first surface (142) of the first copper foil layer (140) is flush with a second surface (122) of the surface copper layer (120); A second drilling process is performed on the surface copper layer (120) and the printed circuit board (110) to form a second through hole (T2), wherein a second inner sidewall (118) of the printed circuit board (110) is exposed through the second through hole (T2); and a second copper foil layer (160) is formed on the second inner sidewall (118) and the surface copper layer (120) of the printed circuit board (110), wherein a first copper plating thickness (H1) above the upper surface (112) of the printed circuit board (110) is the same as a second copper plating thickness (H2) above the lower surface (114) of the printed circuit board (110).

2. The method for manufacturing a circuit board structure with double-sided copper foil as described in claim 1 further includes: Before forming the first copper foil layer (140) on the protective layer (130), the surface copper layer (120) exposed from the first through hole (T1), and the first inner sidewall (116) of the printed circuit board (110), a conductor-forming process is performed on the protective layer (130) and the first inner sidewall (116) of the printed circuit board (110).

3. The method for manufacturing a circuit board structure with double-sided copper foil as described in claim 1 further includes: Before removing a portion of the first copper foil layer (140) and the protective layer (130), a resin plug hole (150) is formed in the first through hole (T1).

4. The method for manufacturing a circuit board structure with double-sided copper foil as described in claim 3, wherein removing a portion of the first copper foil layer (140) and the protective layer (130) further comprises: A brushing process is performed to remove the first copper foil layer (140) above the protective layer (130); an etching process is performed to remove the first copper foil layer (140) between the protective layer (130) and the resin plug (150); the protective layer (130) is removed; and a planarization process is performed to give the first copper foil layer (140) the first surface (142), the surface copper layer (120) the second surface (122), and the resin plug (150) a plug surface (152).

5. The method for manufacturing a circuit board structure with double-sided copper foil as described in claim 4 further includes: Before forming the second copper foil layer (160) on the second inner sidewall (118) and the surface copper layer (120) of the printed circuit board (110), a conductor-forming process is performed on the plugging surface (152) of the resin plugging hole (150) and the second inner sidewall (118) of the printed circuit board (110).

6. A method for manufacturing a circuit board structure with double-sided copper foil as described in claim 4, wherein the planarization process further includes: Remove a portion of the resin plug (150) so that the first surface (142) of the first copper foil layer (140) is flush with the second surface (122) of the surface copper layer (120) and the plug surface (152) of the resin plug (150).

7. The method for manufacturing a circuit board structure with double-sided copper foil as described in claim 1 further includes: A patterning process is performed on the surface copper layer (120) and the second copper foil layer (160) located on the surface copper layer (120) to form an opening (O); and a solder resist layer (170) is formed in the opening (O), wherein the solder resist layer (170) partially extends onto the second copper foil layer (160).

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