Title :
Improvement of CD uniformity in 180 nm LSI manufacturing by optimizing illumination system
Author :
Yao, Teruyoshi ; Hiraike, Tadahiro ; Kobayashi, Katsuyoshi ; Asai, Satoru ; Hanyu, Isamu
Author_Institution :
Fujitsu Ltd., Mie, Japan
Abstract :
Line width control is a key factor in LSI manufacturing. This paper describes the relationship between line width uniformity and the illumination system of an exposure tool. Variation in the local value of partial coherence a is the cause of the optical proximity effect (OPE) variation across the image field of an exposure tool. By quantifying partial coherence σ and decreasing a variation, OPE variation within the image field was improved from 21.2 nm to 8.8 nm. We reduced OPE variation among tools by setting up these tools with agreeing a values. This paper also discusses the effect of illumination source uniformity on line width. Nonuniformity of an illumination source induces a line width difference between pair lines. We improved the treatment for these problems by adjusting the illumination source uniformity
Keywords :
VLSI; integrated circuit manufacture; large scale integration; light coherence; proximity effect (lithography); ultraviolet lithography; 180 nm; CD uniformity; LSI manufacturing; OPE variation; critical dimension variation control; deep-UV exposure tool; illumination source uniformity; illumination system optimisation; image field; line width control; line width uniformity; optical proximity effect; partial coherence; Computed tomography; Control systems; High speed optical techniques; Large scale integration; Lighting; Logic devices; Manufacturing; Optical control; Optical devices; Proximity effect;
Conference_Titel :
Semiconductor Manufacturing Symposium, 2001 IEEE International
Conference_Location :
San Jose, CA
Print_ISBN :
0-7803-6731-6
DOI :
10.1109/ISSM.2001.962930
