Multi-layer circuit board and manufacturing method thereof

Abstract

This invention discloses a multilayer circuit board and its manufacturing method. The multilayer circuit board includes a metal layer, a circuit board structure, a film, and a filler material. The circuit board structure includes a substrate, a first copper layer, and a second copper layer, which are formed on the substrate and located on the same side of the substrate. The first copper layer and the second copper layer are spaced apart from each other. The film connects the metal layer and the circuit board structure, and the filler material fills the space between the circuit board structure and the film. The film is connected to the first copper layer of the circuit board structure. The first copper layer has a first thickness, and the second copper layer has a second thickness, wherein the first thickness is at least four times the second thickness.

Claims

1. A multilayer circuit board, comprising: A metal layer; A circuit board structure includes: a substrate having an upper surface and a lower surface located on opposite sides; a first copper layer formed on the substrate; and a second copper layer formed on the substrate; wherein the first copper layer and the second copper layer are located on the same side of the substrate and are spaced apart from each other; a film connecting the metal layer and the circuit board structure; and a filler material filling the space between the circuit board structure and the film; wherein the film is connected to the first copper layer of the circuit board structure, the first copper layer having a first thickness, the second copper layer having a second thickness, and the first thickness being at least four times the second thickness; wherein the metal layer is spaced apart from and not electrically coupled to the circuit board structure through the film and the filler material.

2. The multilayer circuit board as described in claim 1, wherein, The first copper layer of the circuit board structure has a first top surface and a first bottom surface; wherein the first bottom surface is attached to the substrate and the first top surface is attached to the film.

3. The multilayer circuit board as described in claim 1, wherein, The second copper layer has a second top surface and a second bottom surface; wherein the second bottom surface is attached to the substrate, and the second top surface is covered by the filler material.

4. The multilayer circuit board as described in claim 1, wherein, The circuit board structure further includes a third copper layer, and the third copper layer, the first copper layer and the second copper layer are spaced apart from each other; wherein, the third copper layer has a third thickness, the thickness of the third thickness being between the first thickness and the second thickness.

5. The multilayer circuit board as described in claim 4, wherein, The third thickness is at least twice the second thickness, and the first thickness is at least twice the third thickness.

6. The multilayer circuit board as described in claim 4, wherein, The third copper layer has a third top surface and a third bottom surface; wherein the third bottom surface is attached to the substrate, and the third top surface is covered by the filler material.

7. The multilayer circuit board as described in claim 1, wherein, The metal layer is a patterned circuit layer; wherein the filling material has a filling thickness, and the filling thickness is equal to the first thickness.

8. The multilayer circuit board as described in claim 1, wherein, The filler material is a resin ink, and the film is an insulating prepreg composed of glass fiber material and epoxy resin.

9. A multilayer circuit board, comprising: Two metal layers; A circuit board structure includes: a substrate having an upper surface and a lower surface located on opposite sides; two first copper layers formed on the upper surface and the lower surface of the substrate, respectively; and two second copper layers formed on the upper surface and the lower surface of the substrate, wherein the first copper layers and the second copper layers are spaced apart from each other; two films, each of the metal layers being connected to the circuit board structure via one of the films; and a filler material filling the space between the circuit board structure and each of the films; wherein the two films are respectively connected to the two second copper layers of the circuit board structure, and each first copper layer has a first thickness, each second copper layer has a second thickness, and the first thickness is at least four times the second thickness; wherein the two metal layers are spaced apart from and not electrically coupled to the circuit board structure via the two films and the filler material.

10. A method for manufacturing a multilayer circuit board, comprising: A preliminary step provides an unprocessed circuit board structure and a dry film; A first film-applying step, applying the dry film to the area of ​​the circuit board structure where a first copper layer is to be formed; a first copper thinning step, performing a copper thinning operation on the circuit board structure; a first film removal step, removing the dry film; a second film-applying step, applying the dry film to the area of ​​the circuit board structure where the first copper layer and a second copper layer are to be formed. The circuit board structure is subjected to a second thin copper step, which exposes a portion of the surface of a substrate in the circuit board structure; a second film removal step, which removes the dry film; a solder resist step, which applies a filler material to the circuit board structure; a lamination step, which laminates a metal layer onto the circuit board structure using a film; and a processing step, which processes the metal layer to form a patterned circuit layer.

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