Flexible circuit board and manufacturing method thereof

Abstract

A flexible circuit board comprises a conductive line layer, two photosensitive resin layers and two electromagnetic shielding layers. The conductive line layer comprises at least one signal line, two grounding lines located on two sides of the signal line respectively and at least two gaps. Each gap comprises two opening portions located on two end portions of the corresponding signal line respectively. The two photosensitive resin layers cover two opposite surfaces of the signal line, cover the opening portions respectively and are combined with each end portion of the grounding lines. The two electromagnetic shielding layers cover surfaces of the two photosensitive resin layers, the grounding lines and the gaps, wherein the surfaces of the two photosensitive resin layers are far away from the signal lines; the grounding lines do not combine with the photosensitive resin layers; and the gaps are not covered by the photosensitive resin layers. Therefore, the electromagnetic shielding layers, the photosensitive resin layers, the signal lines and the grounding lines commonly surround areas of each gap so as to form an accommodation chamber, wherein the areas of each gap are not covered by the photosensitive resin layers. Each accommodation chamber is connected to the two opening portions of the corresponding gap so as to form a chamber.

Description

technical field [0001] The invention relates to a flexible circuit board and a manufacturing method thereof. Background technique [0002] The signal attenuation on the high-frequency transmission signal line mainly comes from the attenuation caused by the dielectric loss, wherein the dielectric loss is proportional to the dielectric loss factor and the dielectric constant. The manufacturing method of radio frequency circuit boards in the industry usually uses liquid crystal polymer (Liquid Crystal Polymer, LCP), Teflon (Teflon) or pure rubber as the base material for covering signal lines. However, the dielectric loss of the above-mentioned materials is still relatively large, resulting in relatively large signal attenuation in the transmission line of the circuit board made of the above-mentioned materials. Contents of the invention [0003] In view of this, it is necessary to provide a flexible circuit board with little signal attenuation. [0004] In addition, it is ...

AI Technical Summary

Problems solved by technology

However, the dielectric loss of the above materials is still relatively large, resulting in a large signal attenuation in the transmission line of the circuit board made of the above materials

Images