Development Of Bipolar HIPIMS Power Supplyand Study Of Cr Film Deposition On PI Surface

Compared with DC and pulsed magnetron sputtering,high-power pulsed magnetron sputtering has higher peak current and peak power,and can produce solid films with good density and film-based binding force,but it cannot solve the problem of insulating materials.Based on this problem,this paper proposes a new method of positive and negative bipolar high-power pulsed magnetron sputtering,simulates the main circuit topology,successfully developed a new type of magnetron sputtering power supply.A positive and negative bipolar high power magnetron sputtering coating system was used to deposit a metal film on the surface of polyimide,and the plasma discharge behavior,surface morphology,structure and mechanical properties of the deposited layer were investigated during the deposition process to reveal The mechanism of the deposition process and the law of performance evolution are described.This paper uses PLECS simulation software to construct the main circuit topology,focusing on the construction of the chopper control module of the circuit.Based on the analysis of the target voltage,target current waveform and the actual application conditions of the waveform output by different chopper modules.In addition,based on the topology of the simulation circuit,a new type of magnetron sputtering power supply is made in this paper.In the process of developing new power supply,the circuit topology is selected and calculated.Among them,the filter capacitor is 190?F,the inverter bridge is a full-bridge inverter circuit,and the rectifier bridge includes the secondary transformer,rectifier bridge,filter capacitor,chopper control module and load.The turns ratio of the primary end and the two secondary ends of the transformer is 1:2 and 1:1.According to the constructed circuit,the influence of different discharge waveforms on the plasma discharge behavior is studied.The results show that the positive voltage can improve the stability of the metal discharge.With the increase of positive voltage,the width and stability of metal discharge increase significantly.Different discharge waveforms were used to deposit Cr film on the surface of PI.Among them,the morphology of the Cr film prepared by the HIPIMS discharge waveform is striped.The morphology of the Cr film prepared by the BP-HIPIMS discharge waveform is gray-black uniformly distributed dot-shaped morphology.The surface morphology of the Cr film prepared by the DP-HIPIMS and DBP-HIPIMS discharge waveforms were gray-black network-like morphology and dark island andthe surrounding white interface.Adding positive voltage can effectively improve the surface roughness of the film.The discharge waveforms of BP-HIPIMS and DBP-HIPIMS correspond to Rmax of 15.9nm and 30.6nm,and Ra of 2.9nm and3.5nm,respectively.The phase structure of the PI-Cr thin film is ?-Cr crystal,and the corresponding crystal orientation of the Cr(110)close-packed plane is the preferred growth direction of the Cr film.The scratching method was used to evaluate the bonding strength of the PI-Cr film.The loading force of the film corresponding to the discharge waveforms of BP-HIPIMS and DBP-HIPIMS was 23.5N and 22 N,and the loading force was significantly improved compared with the film prepared by the discharge waveforms of HIPIMS and DP-HIPIMS.The organic paint cross-cut method was used to grade the film adhesion,and the ASTM grade was 5B.A pin-disk friction and wear testing machine was used to test the tribological properties of the film.The results show that the initial friction coefficients corresponding to the discharge waveforms of BP-HIPIMS and DBP-HIPIMS are higher than 0.25.The initial friction coefficients corresponding to HIPIMS and DP-HIPIMS discharge waveforms are both less than 0.2.However,the BP-HIPIMS and DBP-HIPIMS discharge waveforms correspond to 221.8?m and 217.8?m,respectively,which are smaller than the HIPIMS and DP-HIPIMS discharge waveforms.However,the BP-HIPIMS and DBP-HIPIMS discharge waveforms correspond to film wear widths of 221.8 ?m and 217.8 ?m,which are smaller than those of HIPIMS and DP-HIPIMS discharge waveforms.