CN-116156732-B - Bending-resistant circuit board and manufacturing method thereof

CN116156732BCN 116156732 BCN116156732 BCN 116156732BCN-116156732-B

Abstract

A manufacturing method of a bending-resistant circuit board comprises the steps of providing a circuit substrate, wherein the circuit substrate comprises a bending layer and a circuit structure arranged on one side of the bending layer, the circuit structure comprises a plurality of first conductive circuits, the plurality of first conductive circuits are arranged at intervals, and a first line distance groove is formed between every two adjacent first conductive circuits. And a first protective layer is arranged on the circuit structure, each first conductive circuit is covered by the first protective layer, part of the first protective layer is filled in the first line distance groove, and the thickness of the first protective layer is smaller than the depth of the first line distance groove. The manufacturing method of the bending-resistant circuit board provided by the application can improve the bending times and the bending angle. In addition, the application also provides a bending-resistant circuit board.

Inventors

LI CHENGJIA
YANG MEI
GAO CHUNLAN

Assignees

宏启胜精密电子(秦皇岛)有限公司
鹏鼎控股(深圳)股份有限公司

Dates

Publication Date: 20260512
Application Date: 20211119

Claims (7)

1. A manufacturing method of a bending-resistant circuit board is characterized by comprising the following steps: providing a circuit substrate, wherein the circuit substrate comprises a flexible layer and a circuit structure arranged on one side of the flexible layer, the circuit structure comprises a plurality of first conductive circuits, the plurality of first conductive circuits are arranged at intervals, and a first line distance groove is formed between every two adjacent first conductive circuits; arranging a first protection layer on the circuit structure, wherein the first protection layer covers each first conductive circuit, part of the first protection layer is filled in a first line distance groove, and the thickness of the first protection layer is smaller than the depth of the first line distance groove; the step of disposing a first protective layer on the circuit structure includes: a dry film solder resist layer is arranged on the first conductive circuit, the dry film solder resist layer coats the first conductive circuit, and part of the dry film solder resist layer is filled in the first line-spacing groove; exposing a part of the dry film solder resist layer around the first conductive circuit to obtain a part of the protective layer; Removing part of the dry film solder resist layer in the first line-spacing groove, wherein the other part of the dry film solder resist layer is arranged at the bottom of the first line-spacing groove, and the part of the dry film solder resist layer arranged at the bottom of the first line-spacing groove is connected with the part of the protective layer coating the first conductive circuit; exposing a part of the dry film solder resist layer arranged at the bottom of the first linear distance groove to obtain another part of the protective layer.
2. The method of manufacturing a circuit board according to claim 1, wherein the circuit structure further includes a buried circuit and an intermediate circuit, the intermediate circuit being disposed between the buried circuit and the first conductive circuit, the buried circuit being disposed in the flex layer, the method of manufacturing the circuit board comprising the steps of: providing a first copper foil layer; A first photosensitive pattern and a second photosensitive pattern are respectively arranged on two opposite surfaces of the first copper foil layer, the first photosensitive pattern is penetrated and provided with a plurality of first wire grooves, the second photosensitive pattern is penetrated and provided with a plurality of second wire grooves, the first wire grooves and the second wire grooves are correspondingly arranged, and part of the first copper foil layer is exposed at the bottoms of the first wire grooves and the second wire grooves; the first conductive circuit is arranged in the first wire slot, the embedded circuit is arranged in the second wire slot, and the first conductive circuit is correspondingly arranged with the embedded circuit; removing the first photosensitive pattern and the second photosensitive pattern to form a second line-spacing groove between every two adjacent embedded circuits, wherein the first line-spacing groove and the second line-spacing groove are correspondingly arranged, and Arranging the flex layer on the embedded circuit, filling part of the flex layer into the second line-space groove, and And removing part of the first copper foil layer corresponding to the first line-space groove or the second line-space groove to form the intermediate circuit, so as to obtain the circuit substrate.
3. The method of manufacturing of claim 2, further comprising the step of: A second copper foil layer is arranged on the other side of the flexible layer, which is away from the first conductive circuit; an opening is formed in the second copper foil layer, the opening penetrates through the second copper foil layer and the flexible layer, and part of the embedded circuit is exposed out of the bottom of the opening; Providing a plating layer on the second copper foil layer, partially filling the plating layer into the openings to form a via, and Etching the electroplated layer and the second copper foil layer to form a plurality of second conductive circuits, wherein the conductive body is electrically connected with the second conductive circuits and the embedded circuits, the second conductive circuits are arranged at intervals, and a third line distance groove is formed between every two adjacent second conductive circuits.
4. A method of manufacturing as claimed in claim 3, further comprising the step of: Arranging a photosensitive ink layer on the second conductive circuit, wherein part of the photosensitive ink layer is filled in the third linear distance groove; Exposing a part of the photosensitive ink layer outside the second conductive circuit to form a second protection layer, wherein the second protection layer covers the second conductive circuit.
5. The method of manufacturing of claim 4, further comprising the step of: And removing the other part of the unexposed photosensitive ink layer, so that a window is formed on the second protective layer, and the window is arranged corresponding to the third line-spacing groove.
6. The method of manufacturing of claim 1, wherein the dry film solder resist layer comprises a polymerized monomer, an acrylate, an adhesive, and a photoinitiator.
7. A bending-resistant circuit board is characterized by comprising a circuit substrate, a first protective layer, a second protective layer, a conducting body and a plurality of second conductive circuits, The circuit substrate comprises a flex layer and a circuit structure arranged on one side of the flex layer, the circuit structure comprises a plurality of first conductive circuits, a plurality of embedded circuits and a plurality of intermediate circuits, the intermediate circuits are arranged between the embedded circuits and the first conductive circuits, the embedded circuits are arranged in the flex layer at intervals, a second line distance groove is formed between every two adjacent embedded circuits, the intermediate circuits are arranged in the embedded circuits, and the first conductive circuits are arranged in the intermediate circuits; the first conductive circuits are arranged at intervals, a first line distance groove is arranged between every two adjacent first conductive circuits, each first conductive circuit is covered by a first protective layer, part of the first protective layer is filled in the first line distance groove, the thickness of the first protective layer is smaller than the depth of the line distance groove, the first protective layer is a dry film solder resist layer, The second conductive circuit is arranged at one side of the flexible layer away from the first conductive circuit at intervals, the conducting body is arranged in the flexible layer and is electrically connected with the embedded circuit and the second conductive circuit, the second protective layer coats the second conductive circuit, The flexible layer comprises an adhesive layer and an insulating layer, wherein the adhesive layer is arranged between the insulating layer and the second conductive circuit, part of the adhesive layer is filled in the second line distance groove, and the second conductive circuit is arranged on the insulating layer.

Description

Bending-resistant circuit board and manufacturing method thereof Technical Field The application relates to a bending-resistant circuit board and a manufacturing method thereof. Background In recent years, flexible electronic products that are curled or foldable are becoming popular, and flexible circuit boards applied to such electronic products are required to have excellent flexibility and bending resistance at high frequencies. In general, a cavity is required to be formed inside the flexible circuit board to facilitate bending, however, the formation of the cavity not only prevents the formation of the via hole, but also reduces the overall wiring density of the flexible circuit board. Disclosure of Invention In order to solve the problems in the background technology, the application provides a manufacturing method of a bending-resistant circuit board. In addition, the application also provides a bending-resistant circuit board. A manufacturing method of a bending-resistant circuit board comprises the steps of providing a circuit substrate, wherein the circuit substrate comprises a bending layer and a circuit structure arranged on one side of the bending layer, the circuit structure comprises a plurality of first conductive circuits, the plurality of first conductive circuits are arranged at intervals, and a first line distance groove is formed between every two adjacent first conductive circuits. And a first protective layer is arranged on the circuit structure, each first conductive circuit is covered by the first protective layer, part of the first protective layer is filled in the first line distance groove, and the thickness of the first protective layer is smaller than the depth of the first line distance groove. Further, the circuit structure further includes an embedded circuit and an intermediate circuit, the intermediate circuit is disposed between the embedded circuit and the first conductive circuit, the embedded circuit is disposed in the flexible layer, and the method for manufacturing the circuit substrate includes the steps of: A first copper foil layer is provided. The first photosensitive patterns and the second photosensitive patterns are respectively arranged on two opposite surfaces of the first copper foil layer, the first photosensitive patterns penetrate through a plurality of first wire grooves, the second photosensitive patterns penetrate through a plurality of second wire grooves, the first wire grooves and the second wire grooves are correspondingly arranged, and part of the first copper foil layer is exposed out of the bottoms of the first wire grooves and the second wire grooves. The first conductive circuit is arranged in the first wire slot, the embedded circuit is arranged in the second wire slot, and the first conductive circuit and the embedded circuit are correspondingly arranged. Removing the first photosensitive pattern and the second photosensitive pattern, so that a second line-spacing groove is formed between every two adjacent embedded circuits, the first line-spacing groove and the second line-spacing groove are correspondingly arranged, the flexible layer is arranged on the embedded circuits, part of the flexible layer is filled in the second line-spacing groove, and part of the first copper foil layer corresponding to the first line-spacing groove or the second line-spacing groove is removed to form an intermediate circuit, so that the circuit substrate is obtained. Further, the method further comprises the step of arranging a second copper foil layer on the other side of the flexible layer, which is away from the first conductive circuit. And opening holes in the second copper foil layer, wherein the openings penetrate through the second copper foil layer and the flexible layer, the openings are arranged corresponding to the embedded circuits, and part of the embedded circuits are exposed out of the bottoms of the openings. The electroplating layer is arranged on the second copper foil layer, part of the electroplating layer is filled in the open hole to form a conducting body, the conducting body electrically conducts the embedded circuit and the second copper foil layer, the electroplating layer and the second copper foil layer are etched to form a plurality of second conductive circuits, the second conductive circuits are arranged at intervals, and a third line distance groove is formed between every two adjacent second circuits. Further, the method comprises the step of arranging a photosensitive ink layer on the second conductive circuit, wherein part of the photosensitive ink layer is filled in the third linear distance groove. Exposing a part of the photosensitive ink layer outside the second conductive circuit to form a second protective layer. And removing another part of the photosensitive ink layer which is not photosensitive, so that the area of the second protective layer corresponding to the third line-space groove is provided with a window.