Flexible circuit board and method of manufacturing the same

Abstract

This application discloses a flexible circuit board and a method for manufacturing the same. The flexible circuit board includes a first flexible circuit substrate, a conductive adhesive, and a second flexible circuit substrate. The first flexible circuit substrate includes a structural reinforcement layer. The structural reinforcement layer includes multiple metal reinforcement structures and a non-conductive adhesive. The multiple metal reinforcement structures are spaced apart in the non-conductive adhesive. Each metal reinforcement structure includes a spacer wall, a first surrounding wall, and a second surrounding wall. The first surrounding wall and the second surrounding wall are respectively disposed on two opposite surfaces of the spacer wall. The first surrounding wall and the second surrounding wall surround the boundary of the spacer wall and extend in opposite directions. The second flexible circuit substrate is stacked with the first flexible circuit substrate. The second flexible circuit substrate is electrically connected to the first flexible circuit substrate via the conductive adhesive.

Claims

1. A flexible circuit board, comprising: a first flexible circuit substrate, comprising: a structural reinforcement layer including a plurality of metal reinforcement structures and a non-conductive adhesive, wherein the plurality of metal reinforcement structures are spaced apart in the non-conductive adhesive, each of the plurality of metal reinforcement structures including a spacer wall, a first surrounding wall and a second surrounding wall, wherein the first surrounding wall and the second surrounding wall are respectively disposed on two opposite surfaces of the spacer wall, the first surrounding wall and the second surrounding wall surround the boundary of the spacer wall and extend in opposite directions, wherein the first surrounding wall and the second surrounding wall extend in a direction away from the spacer wall, the first surrounding wall and the spacer wall together define a first open space, and the second surrounding wall and the spacer wall together define a second open space; a first conductive adhesive; and a second flexible circuit substrate, stacked with the first flexible circuit substrate, wherein the second flexible circuit substrate is electrically connected to the first flexible circuit substrate via the first conductive adhesive.

2. The flexible circuit board as claimed in claim 1, wherein the first flexible circuit board further comprises: a first circuit layer; a second conductive adhesive; a second circuit layer including a bending portion, wherein the second circuit layer is stacked with the structural reinforcement layer and the first circuit layer, and the structural reinforcement layer is located between the first circuit layer and the second circuit layer, while the second circuit layer is located between the structural reinforcement layer and the second flexible circuit board, the bending portion is bent toward the first circuit layer so that the second circuit layer surrounds the structural reinforcement layer, and the bending portion is electrically connected to the first circuit layer via the second conductive adhesive.

3. The flexible circuit board as claimed in claim 2, wherein the first flexible circuit board further comprises: a first insulating protective layer covering the second circuit layer and exposing a portion of the second circuit layer, wherein the second circuit layer is electrically connected to the second flexible circuit board from the portion exposed from the first insulating protective layer.

4. The flexible circuit board as claimed in claim 2, further comprising: a first electronic component electrically connected to the first flexible circuit board, wherein the first flexible circuit board is located between the first electronic component and the second flexible circuit board.

5. The flexible circuit board of claim 1, wherein the second flexible circuit board comprises: an adhesive layer; a third circuit layer including a connecting portion and a folded portion, wherein the connecting portion is electrically connected to the first flexible circuit board via the first conductive adhesive, and the folded portion is folded toward a direction away from the first flexible circuit board such that the third circuit layer surrounds the adhesive layer, wherein the adhesive layer is sandwiched between the connecting portion and the folded portion.

6. The flexible circuit board as claimed in claim 5, further comprising: a second electronic component electrically connected to the third circuit layer and located between the connection portion and the fold portion, wherein the adhesive layer covers the second electronic component.

7. The flexible circuit board as claimed in claim 5, wherein the second flexible circuit board further comprises: a second insulating protective layer covering the third circuit layer and exposing a portion of the connection portion, wherein the connection portion is electrically connected to the first flexible circuit board from the portion exposed from the second insulating protective layer.

8. A method of manufacturing a flexible circuit board, comprising: providing a carrier board, wherein the carrier board includes a first metal layer and a support layer stacked on top of each other; forming a plurality of first surrounding walls on the first metal layer, wherein the plurality of first surrounding walls are spaced apart on the first metal layer; after forming the plurality of first surrounding walls, covering the first metal layer and the plurality of first surrounding walls with a non-conductive adhesive; after applying the non-conductive adhesive, removing the support layer to expose the first metal layer; after exposing the first metal layer, forming a plurality of second surrounding walls on the first metal layer, wherein the first metal layer is located between the plurality of first surrounding walls and the plurality of second surrounding walls, and the vertical projections of the plurality of second surrounding walls onto the first metal layer respectively overlap with the vertical projections of the plurality of first surrounding walls onto the first metal layer; after exposing the first metal layer, patterning the first metal layer to form a plurality of spacer walls; After forming the plurality of second surrounding walls and the plurality of spacer walls, another non-conductive adhesive is applied to the plurality of second surrounding walls and the plurality of spacer walls to form a structural reinforcement layer, wherein the first surrounding walls and the second surrounding walls extend away from the spacer walls, the first surrounding walls and the spacer walls together define a first open space, and the second surrounding walls and the spacer walls together define a second open space; a first flexible substrate is formed; the first flexible substrate and the structural reinforcement layer are combined to form a first flexible circuit substrate; a second flexible circuit substrate is formed; and the first flexible circuit substrate and the second flexible circuit substrate are combined, wherein the first flexible circuit substrate and the second flexible circuit substrate are electrically connected using a conductive adhesive.

9. The method of manufacturing a flexible circuit board as claimed in claim 8, further comprising: after bonding the first flexible substrate and the structural reinforcement layer, and before forming the first flexible circuit board, surrounding the structural reinforcement layer in the first flexible substrate.

10. A method of manufacturing a flexible circuit board as claimed in claim 8, wherein forming the second flexible circuit board comprises: providing a second flexible substrate; covering the second flexible substrate with an adhesive layer; and surrounding the adhesive layer in the second flexible substrate.

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