TWI708542B - Adhesive copper foil build-up process - Google Patents

Abstract

An adhesive copper foil build-up process includes: (1) providing a base circuit board, the base circuit board having a build-up surface, the build-up surface having a first circuit layer; (2) attaching a roll-up adhesive copper foil to the build-up surface by a vacuum lamination method, the adhesive cooper foil having a copper foil layer and an insulating cement layer, the insulating cement layer being coated on the copper foil layer, the first circuit layer being in contact with the insulating cement layer but not the copper foil layer; (3) plating an electroplated copper layer on the copper foil layer; and (4) patterning the copper foil layer and the electroplated copper layer into a second circuit layer. Thereby, the board build-up efficiency can be significantly improved.

Description

Adhesive copper foil build-up process

The invention relates to a circuit board technology, in particular to a layer build-up technology of a circuit board.

With the popularization of electronic products, the application of circuit substrates has become more and more extensive. As circuit design tends to become more complicated and multilayered, in the past, multiple polypropylene plates with copper foil formed on one or both sides were pressed together to increase However, the prior art board-to-board laminating method is not easy to produce, and the cost is relatively high, which needs to be improved.

In view of this, the main purpose of the present invention is to provide a process for adding layers by changing to a filming method.

In order to achieve the above and other objectives, the present invention provides a back-adhesive copper foil build-up process, which includes: (1) Provide a base circuit board, the base circuit board has an augmented layer, and the augmented layer has a first circuit layer; (2) Adhesive-backed copper foil is attached to the build-up layer by vacuum lamination. The back-adhesive copper foil has a copper foil layer and an insulating adhesive layer, and the insulating adhesive layer is coated on the copper foil layer. , And the first circuit layer contacts the insulating adhesive layer but not the copper foil layer; (3) Electroplating an electroplated copper layer on the copper foil layer; and (4) The copper foil layer and the electroplated copper layer are patterned into a second circuit layer.

In the present invention, the copper foil layer and the insulating adhesive layer are preliminarily formed into a film and reeled, and then the reeled copper foil is attached to the build-up layer by vacuum lamination method, which can greatly improve the efficiency of the build-up. , Simplify the build-up process and solve the problem of the previous board-to-board laminating build-up.

The invention discloses a layer build-up process of a back-adhesive copper foil, which can be used for the build-up operation of a circuit board, and solves the problem of the previous board-to-board laminating buildup.

Hereinafter, the manufacturing process of one embodiment of the present invention will be described with reference to Figures 1, 2, 5 to 8.

First, as shown in Figure 1, a base circuit board 10 is provided. The base circuit board 10 has two build-up layers 11A and 11B, and the build-up layers 11A and 11B respectively have a first circuit layer 12A and 12B. In addition, the base circuit board 10 further has a communicating hole 13 with a copper hole 14 in the communicating hole 13 to electrically connect the two first circuit layers 12A, 12B.

Then, as shown in Figures 2 and 3, use a vacuum lamination leveler to sequentially attach the two original rolled back adhesive copper foils 20 to the respective extension layers 11A and 11B by vacuum lamination. Please go further 4, the back adhesive copper foil 20 has a copper foil layer 21 and an insulating adhesive layer 22, the insulating adhesive layer 22 is coated on the copper foil layer 21, and the first circuit layers 12A, 12B contact the insulating adhesive layer 22 but not Contact the copper foil layer 21. Before the adhesive-backed copper foil 20 is attached, it may further include a protective film 23 attached to the side of the insulating adhesive layer 22 opposite to the copper foil layer 21 to avoid contamination or sticking of the insulating adhesive layer 22. As shown in Figure 3, the protective film 23 is removed before the back adhesive copper foil 20 is attached to the build-up layers 11A, 11B, and after the back adhesive copper foil 20 is attached to the build-up layers 11A, 11B, the insulating adhesive layer 22 It may include, but is not limited to, being fully cured by thermal curing, thereby forming a permanent connection with the build-up layer 11A, 11B.

As shown in Figure 5, in order to electrically connect circuits of different layers, a through hole 30 can be formed through the two back adhesive copper foils 20 and the base circuit board 10, and then as shown in Figure 6, in the through hole 30 The hole copper 31 is formed inside to electrically connect the two copper foil layers 21 with the two first circuit layers 12A and 12B, respectively. In other possible implementations, if it is not necessary to electrically connect circuits of different layers, the steps shown in Figures 5 and 6 can be omitted.

As shown in Figure 7, the two copper foil layers 21 are respectively electroplated with an electroplated copper layer 24, and then as shown in Figure 8, the two sets of copper foil layers 21 and the electroplated copper layer 24 are respectively patterned into two second circuit layers 25. The method of patterning the circuit can be realized by conventional methods of attaching a photolithography film, exposing, developing, alkaline etching, and removing the photolithography film.

In the foregoing embodiments, the base circuit board is a double-layer board, but in other possible embodiments, the base circuit board can also be a single-layer board or other multilayer boards. For example, the structure shown in Figure 8 can be used as the base For the circuit board, the back-adhesive copper foil build-up process of the present invention is performed again.

In the foregoing embodiment, the adhesive-backed copper foil build-up process is performed simultaneously on both sides of the double-layer board. However, in other possible embodiments, the back-adhesive copper foil build-up process can be performed solely on one side of the base circuit board.

10: Base circuit board 11A, 11B: Increase the level 12A, 12B: the first circuit layer 3: Connecting hole 1 14: hole copper 20: Adhesive copper foil 21: Copper foil layer 22: Insulating glue layer 23: Protective film 24: Electroplated copper layer 25: second circuit layer 30: Connecting hole 31: hole copper

Figures 1, 2, 5 to 8 are schematic diagrams of the steps of the build-up process of back adhesive copper foil according to one embodiment of the present invention.

Figure 3 is a schematic cross-sectional view of the back adhesive copper foil.

Figure 4 is a schematic diagram of the vacuum lamination process equipment.

21: Copper foil layer

24: Electroplated copper layer

25: second circuit layer

Claims (5)

A process for adding layers of back adhesive copper foil, including: (1) Provide a base circuit board, the base circuit board has an build-up layer, and the build-up layer has a first circuit layer; (2) Adhesive-backed copper foil is attached to the build-up layer by vacuum lamination. The back-adhesive copper foil has a copper foil layer and an insulating glue layer, and the insulating glue layer is coated on the On the copper foil layer, and the first circuit layer contacts the insulating adhesive layer but not the copper foil layer; (3) Electroplating an electroplated copper layer on the copper foil layer; and (4) Pattern the copper foil layer and the electroplated copper layer into a second circuit layer. The build-up process of back adhesive copper foil as described in claim 1, wherein after step (2), it further includes: (5) A communicating hole penetrating the back adhesive copper foil is formed on the back adhesive copper foil, and a hole copper is formed in the communicating hole to electrically connect the copper foil layer and the first circuit layer. The back-adhesive copper foil build-up process according to claim 2, wherein step (5) is performed before step (3). The back-adhesive copper foil build-up process according to claim 1, wherein the back-adhesive copper foil further comprises a protective film attached to the side of the insulating adhesive layer opposite to the copper foil layer, and the protective film is on the back adhesive copper The foil is removed before being attached to the build-up layer. The back-adhesive copper foil build-up process according to claim 1, wherein after the step (2), the insulating adhesive is completely cured.

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