The Uniformity Control Mechanism of Large Area Vacuum Coating Based on Low Pressure CVD Method

In the large-area uniform deposition of amorphous silicon film by hot-wire chemical vapor deposition, using CFD fluid simulation software, continuous fluid and heat transfer models are established for the reaction chamber. Based on conventional process parameters and following the principle of single control variable, the design series simulation test analyzes the influence of hot wire process parameters on substrate surface temperature and gas flow rate, and discusses the control of the uniformity of the intake flow and the influence of the flow field distribution. The results show that the temperature distribution maintains linear fluctuation under various process parameters, showing good thermal stability; the flow rate fluctuates in a small range, with low center flow rate and high edge flow rate; reasonable inlet flow rate and distribution design can ensure uniform distribution of reaction gas in the deposition room and reduce the difference of film thickness caused by uneven gas flow. Through the comprehensive optimization of the thermal flow field, the membrane thickness uniformity of the amorphous silicon film is reduced to less than 5%, and the film quality and performance are significantly improved.