Research On The High Resistance Resistive Material For System Integrated Flexible Circuit And The Resistance Control Technology

Flexible electronics are widely used in wearable devices,mobile consumer electronics,medical devices,and automotive electronics because they are light,thin,and flexible in any direction.The integration of component systems into insulating resin circuit boards not only enables the miniaturization and lightweighting of electronic devices,but also reduces their parasitic effects in high-frequency applications.Flexible electronics as an important carrier of circuit boards,due to its amorphous structure characteristics lead to the integration of components on its surface has been a research challenge for the industry.To this end,in this paper,high resistance Ni-P-C materials are prepared and flexible integrated resistors are integrated and fabricated on flexible substrates with the help of in-line monitoring technology to solve the problem of systematically integrating resistors on flexible substrates.First,the C-doped Ni-P high-resistance resistor materials were successfully prepared by introducing diethylenetriamine(DETA)into the plating solution based on the in-line monitoring resistance technology.The effects of DETA concentration,plating solution temperature,solution p H and monitoring voltage on the resistance value of the materials were investigated to determine the process conditions for making the high resistive value resistive materials.The results show that the resistance value of the resistive material is more than one order of magnitude higher than that of the pure Ni-P alloy by C-doping.Tests on resistors with different structural designs show that the resistance error of the material is within 10% and has good resistance stability.Cold and heat cycles,high temperature and high voltage,and temperature coefficient of resistance(TCR)tests all show that the C-doped Ni-P high resistance material has good application reliability.Then,the process technology of C-doped Ni-P high resistance materials integrated on polyimide(PI)flexible substrates was explored.The chemical complexation of Pd on the flexible substrate was achieved by KOH chemical modification and catalyzed the chemical deposition of C-doped Ni-P high-resistance resistive materials to successfully integrate the high-resistance materials onto PI flexible substrates to prepare integrated flexible resistors.Fatigue resistance,bending,and thermal reliability tests have shown that the C-doped Ni-P high-resistance material has good plating bonding on the upper surface of PI and can withstand more than 1000 bending cycles.Finally,we designed different structures(horseshoe,folding,and snake),sizes,and square resistances of the flexible integrated resistors,and modeled and calculated their insertion loss and parasitic effects at high frequencies using the finite element simulation software ANSYS.The results show that the parasitic effect of the folded wire type flexible integrated resistor is the smallest in the frequency range of 0-10 GHz.In addition,the resistance of the flexible base material with a square resistance of 200 Ω/sq is only 1/7 of that of the device with a square resistance of 25 Ω/sq.Therefore,the C-doped Ni-P resistor material can not only reduce the resistance size by increasing the square resistance,but also further reduce the parasitic effect.