Substrate Positioning via Continuous Stage Motion for Lithography
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Solution Overview
Problem
Current methods for determining the best focus and precise position of substrates in semiconductor lithography are inefficient due to the need for positioning procedures and settling times, which hinder high throughput and accuracy in capturing image representations for focus stacks.
Innovation Solution
A method involving a movable object stage that varies the distance between the substrate and the imaging optical unit at a constant speed, allowing for continuous image capture without additional positioning procedures, and using image evaluation tools to compensate for image unsharpness, enabling faster and more accurate determination of substrate positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If positioning procedures are used to capture image representations at different z positions, then measurement precision is improved, but productivity deteriorates due to positioning time and settling time
Solution Approach 1:
The patent applies the dynamics principle by continuously moving the object stage at a constant velocity through the defocus region rather than stopping at discrete positions. This dynamic approach captures a continuous sequence of image representations during motion, eliminating positioning and settling times while maintaining sufficient measurement precision through the continuous nature of the data collection
Solution Approach 2:
The patent implements continuity of useful action by capturing image representations continuously during the motion of the object stage through the defocus region. This continuous capture eliminates idle time between discrete measurements, ensuring that the measurement process runs without interruption and maximizes throughput while gathering sufficient data for accurate best focus determination
2Productivity
If the object stage is moved during image capture, then productivity is improved by eliminating positioning time, but measurement precision deteriorates due to image unsharpness
Solution Approach 1:
The patent applies feedback by using image evaluation tools that analyze the continuous sequence of image representations captured during motion. These tools process the images to compensate for motion-induced unsharpness and determine the best focus position, effectively correcting the quality degradation caused by continuous motion while maintaining the productivity benefits
Solution Approach 2:
The patent implements parameter changes by varying the distance between the substrate and imaging optical unit at a constant velocity during image capture. This controlled parameter change allows the system to traverse the defocus region continuously, and the constant velocity ensures predictable image characteristics that can be compensated through image evaluation
Data Source
AI summary
A method for measuring a substrate for semiconductor lithography using a measuring device, wherein the measuring device comprises a recording device for capturing at least a partial region of the substrate and, wherein the distance between the substrate and an imaging optical unit of the recording device is varied while the partial region is captured by the recording device.