Research On Signal Integrity Of Multi-layer LCP Line For 5G High Frequency Communication

Liquid crystal polymer(LCP)are widely used in 5G antennas and high-speed highspeed data transmission because of their's low dielectric constant,low dielectric loss,low moisture absorption,good chemical resistance,and high gas barrier properties.Frequency devices and other fields.At present,the mainstream method of multi-layer LCP circuits is to prepare single and double-sided copper clad laminates after exposure,development,and etching,and then pass the single and double-sided circuits through a layer of low melting point LCP or direct vacuum hot pressing of multiple layers of LCP circuits.However,the LCP will flow during the high-temperature lamination process,causing problems such as line drift,uneven thickness of the line lamination,and discontinuous impedance.Moreover,the lamination can only be performed once,and the alignment accuracy is low,which affects the reliability of the line and the high temperature Pr essing requires a high-temperature press,which is expensive.This article innovatively proposes a method of multi-layer LCP circuit made by bonding single-sided LCP circuit and double-sided LCP circuit by using low-temperature adhesive as an adhesive layer,and the prepared multi-layer circuit is laminated with pure LCP circuit There is little difference in reliability and signal transmission quality,and there is no layered bubble phenomenon.It can be widely used in 5G antennas and highfrequency devices to meet high-frequency low-loss data transmission performance.The main research content of this article is to explore the process methods of multi-layer LCP circuit creation,analyze the effect of pure LCP lamination,5 ?m Nikon glue,10 ?m Nikon glue,25 ?m Nikon glue on signal integrity,research and test multilayer LCP The peel strength of the circuit after lamination,after tin immersion and after reflow soldering and observe the slice data for delamination and blistering,analyze the reliability of the product,measure and compare the multi-layer LCP circuit made by pressing different adhesive thicknesses Insertion loss;use a roughness tester to measure and compare the roughness under micro-etching,browning,and blackening processes,analyze the peel strength of Panasonic,Sony,and Nikon under different processes,and study the optimal adhesive in different roughness Insertion loss under chemical process;after placing the finished multi-layer LCP line in a 25 ?,80% constant temperature and humidity chamber for 60 days,use a vector network analyzer to test its insertion loss.Signal transmission quality before and after board,before and after reflow soldering.Analysis of the signal integrity and reliability test results of the multi-layer LCP line shows that under the browning pre-treatment process,the multi-layer LCP line pressed with 5 ?m Nikon glue is laminated with the pure LCP multi-layer LCP line at 5G frequency The signal transmission quality is comparable,and there are no reliability defects such as layered bubbles,which satisfies the high-frequency low-loss data transmission performance.