Title :
Application of feed-forward control to a lithography stepper
Author :
Leang, Sovarong ; Spanos, Costas J.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., California Univ., Berkeley, CA, USA
Abstract :
Presents a novel feedforward control algorithm that seeks to improve the reproducibility of pattern transfer in modern photolithography process sequences. Coupled with a feedback controller and accurate empirical equipment models, the feedforward controller significantly improves the process capability index (Cpk) of the lithographic sequence by centering its response around the specifications and by reducing its inherent variance. This algorithm has been implemented on a resist coat and expose sequence in the Berkeley Microfabrication Laboratory. Experimental results show that process accuracy can be significantly improved by the application of this algorithm
Keywords :
coating techniques; photolithography; process control; resists; Berkeley Microfabrication Laboratory; empirical equipment models; feed-forward control; feedback controller; lithography stepper; pattern transfer; process capability index; reproducibility; resist coat and expose sequence; variance; Adaptive control; Control systems; Error correction; Feedforward systems; Laboratories; Lithography; Predictive models; Resists; Semiconductor device modeling; Semiconductor process modeling;
Conference_Titel :
Semiconductor Manufacturing Science Symposium, 1992. ISMSS 1992., IEEE/SEMI International
Conference_Location :
San Francisco, CA
Print_ISBN :
0-7803-0680-5
DOI :
10.1109/ISMSS.1992.197641
