Beam Profile Display for Optical Axis Alignment in Excimer Lasers
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Solution Overview
Problem
In semiconductor exposure apparatuses, the large spectral line width of KrF and ArF excimer laser devices leads to chromatic aberration in projection lenses, reducing resolution. To mitigate this, a line narrowing module is often used, but this requires additional components and complexity.
Innovation Solution
A profile display device and laser device configuration that includes a processor to generate a shifted outline of the laser beam profile based on light intensity distribution deviations, allowing for real-time adjustment and display of the beam profile and shifted outline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a line narrowing module is provided in the laser resonator to narrow the spectral line width, then chromatic aberration is reduced and resolution is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent extracts the function of narrowing spectral line width from the traditional line narrowing module (etalon, grating) and implements it through software processing of beam profile data. The processor generates a shifted outline by shifting the position of the beam profile outline according to light intensity distribution deviation, effectively narrowing the spectral line width without physical line narrowing components.
Solution Approach 2:
The patent replaces the mechanical/optical line narrowing module with a computational approach. Instead of using physical components like etalons or gratings to narrow the spectral line width, the system uses a processor to analyze beam profile data and generate a shifted outline, substituting mechanical/optical intervention with digital signal processing.
2Reliability
If the spectral line width is narrowed using traditional methods, then chromatic aberration is reduced, but the device requires additional components and adjustment complexity
Solution Approach 1:
The system performs self-adjustment by automatically analyzing the beam profile and generating a shifted outline based on the detected light intensity distribution. The processor calculates the shift amount and generates the corrected outline without requiring manual intervention, making the system self-regulating and eliminating complex manual adjustment procedures.
Solution Approach 2:
The patent implements a feedback mechanism where the beam profile is continuously monitored, the light intensity distribution deviation is detected, and the shifted outline is generated based on this feedback. This closed-loop control ensures chromatic aberration is continuously compensated without manual adjustment.
3Measurement precision
If beam profile visualization is improved for better adjustment, then optical axis alignment is enhanced, but measurement and detection complexity increases
Solution Approach 1:
The patent creates a copied representation of the beam profile by generating a shifted outline that replicates the beam profile shape but positioned at a shifted location. This copied outline makes the light intensity distribution deviation visually apparent and easier to measure, as the displacement between the original and shifted outlines directly indicates the alignment error.
Data Source
AI summary
A profile display device includes an interface configured to receive a beam profile of laser light, a processor configured to generate a shifted outline by shifting a position of an outline of the beam profile in accordance with deviation of a light intensity distribution in the beam profile, and a display configured to display the beam profile and the shifted outline.