BackgroundFocus-exposure process window measurement and analysis is an essential function in lithography, but the current geometric approach suffers from several significant deficiencies.AimBy clearly identifying the problems with the geometric process window approach, a process window measurement and analysis method will be proposed to address these problems.ApproachThe probabilistic process window (PPW) proposed here takes metrology uncertainty into account and rigorously calculates the expected fraction of in-spec features based on settings for the best dose/focus and presumed random errors in dose and focus. Using the fraction of in-spec features thus calculated, a much more rigorous determination of the trade-off between exposure latitude and depth of focus (DOF) can be performed.ResultsThe PPW approach is demonstrated on focus-exposure data generated from a standard extreme ultraviolet lithography process at three different pitches, showing the value of this method.ConclusionsThe PPW approach offers clear advantages in accuracy for both DOF determination and the best dose/focus determination. Consequently, its use is preferred both for process development applications and high-volume manufacturing.
Background: Focus-exposure process window measurement and analysis is an essential function in lithography, but the current geometric approach suffers from several significant deficiencies. Aim: By clearly identifying the problems with the Geometric Process Window approach, a new process window measurement and analysis method will be proposed to address these problems. Approach: The Probabilistic Process Window proposed here takes metrology uncertainty into account and rigorously calculates the expected fraction of in-spec features based on settings for best dose/focus and presumed random errors in dose and focus. Using the fraction of in-spec features thus calculated, a much more rigorous determination of the trade-off between exposure latitude and depth of focus can be performed. Results: The Probabilistic Process Window approach is demonstrated on focus-exposure data generated from a standard extreme ultraviolet lithography process at three different pitches, showing the value of this method. Conclusions: The new Probabilistic Process Window approach offers clear advantages in accuracy for both depth of focus determination and best dose/focus determination. Consequently, its use is preferred both for process development applications and high-volume manufacturing.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.