PDF-Based Patterning Control for Lithography Defect Reduction
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Solution Overview
Problem
Existing device manufacturing processes, particularly in lithography and metrology, face challenges in accurately adjusting patterning processes to achieve consistent and high-quality pattern transfer on substrates, leading to defects such as necking, line thinning, and other systematic issues.
Innovation Solution
A method is developed to determine adjustments to the patterning process using a probability density function of parameters, incorporating illumination modes, polarization states, and projection system corrections, along with metrology techniques to measure and correct for aberrations and apodization, enabling precise pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional patterning processes are used, then manufacturing throughput is maintained, but pattern transfer accuracy deteriorates due to uncorrected aberrations and apodization
Solution Approach 1:
The patent applies parameter changes by adjusting illumination modes, polarization states, and projection system parameters based on probability density functions of process parameters. This allows the system to compensate for aberrations and apodization effects by dynamically modifying process parameters to achieve desired pattern transfer accuracy.
Solution Approach 2:
The patent implements feedback mechanisms by using metrology measurements to detect actual pattern deviations and comparing them against target specifications. This feedback information is then fed back into the control system to adjust illumination and projection parameters, creating a closed-loop control system that continuously improves pattern transfer accuracy.
2Measurement precision
If comprehensive metrology measurements are performed to detect aberrations, then pattern transfer accuracy is improved, but measurement time increases
Solution Approach 1:
The patent applies preliminary action by performing metrology measurements and characterizing aberrations and apodization effects during setup or calibration phases rather than during every production measurement. This allows the system to pre-determine correction parameters that can be applied during actual patterning operations, reducing real-time measurement requirements.
Solution Approach 2:
The patent uses copying by creating digital models or representations of the actual aberrations and apodization effects through metrology data. These digital copies are then used to generate correction parameters and probability density functions, allowing the system to work with simplified data representations rather than requiring continuous complex measurements during production.
3Manufacturing precision
If multiple process parameters are adjusted to compensate for aberrations, then pattern quality is improved, but process control complexity increases
Solution Approach 1:
The patent manages process control complexity by systematically changing multiple parameters (illumination modes, polarization states, projection system parameters) in a coordinated manner based on probability density functions. This approach allows the system to handle multiple parameters together rather than independently, reducing overall control complexity through unified parameter adjustment strategies.
Solution Approach 2:
The patent applies dynamics by making process parameters adjustable and adaptable rather than fixed. The system dynamically adjusts illumination and projection parameters based on real-time or pre-determined conditions, allowing flexible response to varying aberration and apodization effects while maintaining consistent pattern quality across different processing conditions.
Data Source
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AI summary
Described herein is a method for determining adjustment to a patterning process. The method includes obtaining a probability density function of a parameter related to a feature of a substrate subject to the patterning process based on measurements of the parameter, determining, by a hardware computer system, an asymmetry of the probability density function, and determining, by the hardware computer system, an adjustment to the patterning process based on the asymmetry of the probability density function of the parameter so as to reduce a probability of the feature having a parameter value that falls outside a range between threshold values of the parameter.