Research On Film Thickness Control Technology In Vacuum Ion Plating Equipment

Vacuum ion plating equipment is a kind of equipment for processing surface engineering technology,which is widely used in many fields.The thickness accuracy of the coating film is a key indicator to evaluate the performance of the equipment,and the control performance of the film thickness monitoring system in the equipment directly determines the thickness accuracy of the film.At present,when coating nonquarter film,the control system which is based on a crystal film thickness monitor is generally used.However,Because of the relatively simple algorithm used,the accuracy of the coating film is not enough.Therefore,the application of intelligent algorithms to the film thickness control system in vacuum ion plating equipment has broad prospects for improving the accuracy and quality of the coating film.According to the principle of vacuum ion plating,the film thickness detection methods are analyzed and compared,the characteristics and performance of various monitoring methods are analyzed,and the crystal film thickness monitor is selected to detect the thickness and deposition rate of the film.Based on the previous research,a film thickness control scheme with time control was designed.Which is by controlling the film deposition rate and coating time to indirectly control the film thickness.The characteristics of the coating process are analyzed,established the mathematical model,and obtained specific parameters through experiments.The film thickness control system of the traditional PID controller is constructed,and designed a fuzzy adaptive PID control algorithm on the basis of PID controller.In order to solve the parameter tuning problem of the proportional factor and quantizing factor in the fuzzy PID controller,designed the beetle antennae search particle swarm optimization(BSO)algorithm to tuning these parameters,and verify the effectiveness of the algorithm through simulation experiments.In order to verify the performance of the designed film thickness control algorithm,an industrial computer film thickness control system software was designed based on Lab VIEW.Including the realization of the algorithm module,the realization of the communication and data processing module,the realization of the abnormal alarm module and the control interface module.An experiment platform was built on the vacuum ion plating equipment NRC-1700 to test the fuzzy self-adaptive PID algorithm designed in this paper based on the optimization of BSO.Experimental results show that the algorithm is better than PID control algorithm for the control of coating rate and the accuracy of film thickness control.The control accuracy and reproducibility of the film thickness have been greatly improved,which meets the actual control requirements of the film thickness control system.