Abstract
Two SR steppers, SS-1[1] and SS-2, are used at the NTT SR facility to accelerate the development of LSIs with a feature size of 0.2 microns or less. This paper presents the compatibility of the two SR steppers focusing on overlay accuracy. For stepper to stepper overlay, repeatability and offset controllability are the important factors. The stand-alone overlay repeatability of ±30nm, and offset control resolution of 10nm are achieved. The difference of run-out error between two beamlines, which have an adverse affect on compatibility, are measured. It is less than 60nm in 18mm square. The influence of chucked wafer flatness to overlay accuracy is clarified by experiments and simulations. The overlay accuracy of 60 nm(3 σ) for the two SR steppers is obtained by double exposure methods using the same mask and alignment marks formed by a photo stepper. These two steppers are now being applied to test device fabrication.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
