# US 11,445,618 B2 · Flexible circuit board and method for manufacturing same

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- Number: US 11,445,618 B2
- Document ID: US11445618B2
- Status: Granted
- Kind: B2
- Application number: 17/114,981
- Filed: 2020-12-08
- Published: 2022-05-26
- Granted: 2022-09-13
- Earliest claimed: 2020-11-25
- Assignees: Avary Holding (Shenzhen) Co., Limited.; Qing Ding Precision Electronics (Huaian) Co., Ltd; Garuda Technology Co., Ltd.
- Applicants: Avary Holding (Shenzhen) Co., Limited.; Qing Ding Precision Electronics (Huaian) Co., Ltd; Garuda Technology Co., Ltd.
- Inventors: Yao-Cai Li; Biao Li; Hao-Wen Zhong
- Web page: https://patentgrep.com/patent/US11445618B2

## CPC

- H05K 3/4635: {laminating flexible circuit boards using additional insulating adhesive materials between the boards}
- H05K 1/118: {specially for flexible printed circuits, e.g. using folded portions}
- H05K 3/28: Applying non-metallic protective coatings {(H05K3/0091 takes precedence; methods for intermediate insulating layers for build-up multilayer circuits H05K3/4673)}
- H05K 3/462: {characterized by laminating only or mainly similar double-sided circuit boards}
- H05K 1/028: {Bending or folding regions of flexible printed circuits (H05K1/0283 takes precedence)}
- H05K 3/0011: {Working of insulating substrates or insulating layers}
- H05K 3/4623: {the circuit boards having internal via connections between two or more circuit layers before lamination, e.g. double-sided circuit boards (H05K3/462 takes precedence)}
- H05K 2201/0338: Layered conductor, e.g. layered metal substrate, layered finish layer or layered thin film adhesion layer
- H05K 2201/042: Stacked spaced PCBs; Planar parts of folded flexible circuits having mounted components in between or spaced from each other
- H05K 2201/09509: Blind vias, i.e. vias having one side closed
- H05K 2201/0959: Plated through-holes or plated blind vias filled with insulating material
- H05K 2203/0235: Laminating followed by cutting or slicing perpendicular to plane of the laminate; Embedding wires in an object and cutting or slicing the object perpendicular to direction of the wires
- H05K 2203/1377: Protective layers
- H05K 2203/308: Sacrificial means, e.g. for temporarily filling a space for making a via or a cavity or for making rigid-flexible PCBs
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

A method for manufacturing a flexible circuit board includes providing a first laminated structure, the first laminated structure including two first wiring boards, a first adhesive layer sandwiched between the two first wiring boards, and a first conductive structure. The first conductive structure penetrates the two first wiring boards and the first adhesive layer and electrically connects the two first wiring boards. The first adhesive layer defines a first opening, the first opening includes a first edge away from the first conductive structure. The first laminated structure is cut along the first edge and then the two first wiring boards are unfolded. A flexible circuit board manufactured by such method is also disclosed.

## Claims

### Claim 1

A method for manufacturing a flexible circuit board comprising:
providing a first laminated structure, the first laminated structure comprising two first wiring boards, a first adhesive layer sandwiched between the two first wiring boards, and a first conductive structure, the first conductive structure penetrating the two first wiring boards and the first adhesive layer and electrically connecting the two first wiring boards, the first adhesive layer defining a first opening, the first opening comprising a first edge away from the first conductive structure;
cutting the first laminated structure along the first edge;
unfolding the two first wiring boards, thereby obtaining the flexible circuit board;
forming two second laminated structures on opposite sides of the first laminated structure, each of the two second laminated structure comprising a second adhesive layer, a second wiring board stacked on a side of the second adhesive layer, and a second conductive structure, the second conductive structure penetrating the second wiring board and the second adhesive layer and electrically connecting the second wiring board and one of the two first wiring boards, the second conductive structure corresponding in position to the first opening, the second adhesive layer defining a second opening, the first conductive structure corresponding in position to the second opening, the second opening comprising a second edge away from the second conductive structure;
cutting the two second laminated structures along the first edge and cutting the two second laminated structures and the first laminated structure along the second edge; and
unfolding two wiring boards of the two second laminated structures.

### Claim 2 (depends on 1)

The method of claim 1, further comprising pressing two first cover films onto opposite sides of the first laminated structure, each of the two first cover films being sandwiched between the first laminated structure and one of the two second laminated structures.

### Claim 3 (depends on 2)

The method of claim 2, wherein the first conductive structure is a conductive via, each of the two first cover films comprises a first protective layer and a first adhesive coated on a side of the first protective layer, the first adhesive infilling the conductive via.

### Claim 4 (depends on 1)

The method of claim 1, further comprising pressing two second cover films onto two sides of the two second laminated structures away from the first laminated structure.

### Claim 5 (depends on 1)

The method of claim 1, wherein each of the two first wiring boards comprises a first insulation layer and a first conductor layer stacked on a side of the first insulation layer, the first conductor layer is electrically connected to the first conductive structure, the first conductor layer comprises a first end away from the first conductive structure and a second end adjacent to the first adjacent structure; along a thickness direction of the flexible circuit board, a projection of the first end falls in a projection of the first opening, and a projection of the second end falls in a projection of the second opening.

### Claim 6 (depends on 5)

The method of claim 5, wherein the second wiring board comprises a second insulation layer and a second conductor layer stacked on a side of the second insulation layer, the second conductor layer is electrically connected to the second conductive structure, the second conductor layer comprises a third end away from the second conductive structure and a fourth end adjacent to the second conductive structure, along the thickness direction of the flexible circuit board, a projection of the third end falls in the projection of the second opening, and a projection of the fourth end falls in the projection of the first opening.