ch. 1. Introduction to the use of statistical process control in lithography -- ch. 2. Sampling -- ch. 3. Simple and complex processes -- ch. 4. Linewidth control -- ch. 5. Overlay -- ch. 6. Yield -- ch. 7. Process drift and automatic process control -- ch. 8. Metrology -- ch. 9. Control of operations
1. Introduction to the use of statistical process control in lithography -- The assumptions underlying statistical process control -- The properties of statistical process control -- Situations in lithography where statistical process control cannot be applied naively -- Non-normal distributions -- Process capability -- 2. Sampling -- Choosing the proper sample size -- Measurement location considerations -- Correlations -- Measurement frequency -- Systematic sources of variation -- 3. Simple and complex processes -- Definitions -- Why test wafers are useful -- How to address complex processes in lithography -- Distinguishing between layer-specific and equipment-specific effects -- 4. Linewidth control -- Cause and effect -- Independent variables -- Exposure dose -- Resist thickness -- Focus -- Bake temperatures -- Resist development -- Humidity -- DUV resists--special considerations -- Contributions from reticles -- Maximizing the process window -- 5. Overlay -- Overlay models -- Matching -- Contributions from processing and alignment mark optimization -- Addressing the problem of non-normal distributions -- Outliers -- 6. Yield -- Yield monitor strategy -- Yield models -- Parameters which affect yield -- 7. Process drift and automatic process control -- Adjusting for process drift -- The exponentially-weighted moving average -- Automatic process control -- 8. Metrology -- The need for understanding the measurement process: defect detection -- Linewidth measurement using scanning electron microscopes -- Electrical linewidth measurement -- Measurement error budgets -- Measurement of overlay -- 9. Control of operations -- Self-control -- Documentation -- ISO 9000
Summary
This text covers lithography process control at several levels, from fundamental through advanced topics. The book is a self-contained tutorial that works both as an introduction to the technology and as a reference for the experienced lithographer. It reviews the foundations of statistical process control as background for advanced topics such as complex processes and feedback. In addition, it presents control methodologies that may be applied to process development pilot lines
Bibliography
Includes bibliographical references (pages 169-188) and index
