The invention discloses a UPA pressure automatic compensation
system and method for
mask substrate
polishing. The UPA pressure automatic compensation
system comprises a pressure execution module, a distributed sensing feedback network and an
intelligent control unit. Wherein the pressure execution module is used for directly
polishing a
mask base plate and comprises a force application shaft, a
polishing head, an air source, a UPA air bag and an electric
proportional valve, the distributed sensing feedback network comprises an air path
pressure sensor and a
tail end
contact pressure sensor, and the
intelligent control unit receives a collection
signal of the distributed sensing feedback network and sends the collection
signal to the polishing head. On the basis of a current process formula and process parameter
coupling model, a data fusion
algorithm, a feed-forward
compensation algorithm and a
fuzzy PID algorithm are operated to obtain a feed-forward compensation amount and a
fuzzy PID output amount, the feed-forward compensation amount and the
fuzzy PID output amount are superposed, a total control
voltage is generated and output to an electric
proportional valve, and then the input air pressure of a UPA air bag is adjusted. Therefore, closed-
loop control over the polishing pressure of the
mask substrate is achieved. Through multi-sensor data fusion, fuzzy PID self-
adaptive control and intelligent feed-forward compensation based on a process parameter
coupling model, real-time, accurate and constant control of the polishing pressure is realized, so that the surface precision and yield of the mask substrate are improved.