Exposure Illumination Compensation for Working Gap Variation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-uniform working gaps during the exposure process lead to non-uniformity of imaged patterns, affecting the exposure result and potentially causing failure.
Innovation Solution
An illumination compensation method that involves measuring working gaps, calculating imaging light field intensity, constructing a functional dependence of imaged pattern critical dimension on working gaps, and performing illumination compensation using light field modulation technology to adjust light intensity, polarization, and phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the working gap is kept uniform across the exposure area, then the light field intensity distribution remains uniform and critical dimension consistency is maintained, but the complexity of the exposure system increases due to the need for precise gap control mechanisms
Solution Approach 1:
The patent measures the working gap distribution before exposure and calculates the required light field intensity compensation in advance. By performing these calculations and preparations beforehand, the system avoids the need for complex real-time gap adjustment mechanisms during exposure, thus maintaining critical dimension uniformity without significantly increasing device complexity.
Solution Approach 2:
The patent changes the illumination light parameters (intensity, polarization, phase) as a function of position to compensate for working gap variations. Instead of mechanically adjusting the working gap to be uniform, the system accepts the non-uniform gap and compensates by modulating light parameters, thereby maintaining critical dimension uniformity while avoiding complex mechanical adjustment mechanisms.
2Manufacturing precision
If illumination light parameters are modulated to compensate for working gap variations, then critical dimension uniformity is improved, but the complexity of the illumination system increases
Solution Approach 1:
The patent introduces a light field modulator as an intermediary component between the illumination source and the mask. This modulator adjusts the light parameters (intensity, polarization, phase) according to the measured working gap distribution, enabling compensation for gap variations without requiring complex mechanical adjustments to the exposure system itself.
Solution Approach 2:
The patent replaces potential mechanical adjustment mechanisms with optical field modulation. Instead of physically adjusting components to compensate for working gap variations, the system uses light field modulation (intensity, polarization, phase) to achieve the same compensation effect, thereby reducing mechanical complexity while improving critical dimension uniformity.
3Ease of manufacture
If the working gap varies across the exposure area, then the exposure process becomes simpler with less stringent mechanical tolerances, but the light field intensity becomes non-uniform causing critical dimension variations
Solution Approach 1:
The patent converts the harmful effect of non-uniform working gap (which causes non-uniform light field and critical dimension variations) into a useful compensation signal. By measuring the working gap distribution and using it to calculate and apply light field intensity compensation, the system transforms the gap variation problem into an opportunity for targeted illumination adjustment, thereby maintaining critical dimension uniformity despite mechanical variations.
Solution Approach 2:
The patent implements a feedback mechanism where the working gap distribution is measured and used to determine the required illumination compensation. The measured gap information feeds into calculations that determine the appropriate light field modulation parameters, which are then applied to compensate for the gap variations. This closed-loop feedback approach maintains critical dimension uniformity while allowing mechanical tolerances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the uniformity of critical dimensions in imaged patterns by compensating for variations in working gaps, enhancing imaging quality and ensuring consistent pattern formation across large areas.
Implementation Method 1
adjusting parameters such as light intensity, polarization, and phase of incident light at different positions to achieve uniformity of the imaging light field in the photoresist layer
Implementation Method 2
The evanescent waves carrying sub-wavelength information of the mask pattern undergo photochemical reaction with the photoresist layer spin-coated on the substrate
Data Source
AI summary
An illumination compensation method, comprising: acquiring working gaps between an imaging film stack and a mask in an exposure imaging system; calculating imaging light field intensities of a photoresist layer in the imaging film stack corresponding to the different working gaps, and, constructing a functional dependence of imaged pattern critical dimension in the photoresist layer of the imaging film stack on the working gap based on said imaging light field intensity critical dimension; calculating compensation parameters required for illumination light according to the said functional dependence of imaged pattern critical dimension on working gap; and, performing illumination compensation on the exposure imaging system according to the compensation parameters.