Spatial Light Modulator Staggered Scanning for Lithography
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Solution Overview
Problem
Current exposure apparatuses in lithography processes face challenges in achieving high-precision exposure at high throughput due to the time and cost associated with manufacturing mask substrates, and the need for improved exposure precision and efficiency in projecting patterns onto substrates.
Innovation Solution
An exposure apparatus featuring a spatial light modulator with two-dimensionally arranged light modulation elements inclined at a predetermined angle, combined with a substrate holder that scans at a speed to arrange spot positions in a staggered manner, allowing for efficient and precise exposure of a substrate with a reduced number of pulses while maintaining resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask substrate is used for exposure, then exposure precision can be maintained, but manufacturing time and cost increase
Solution Approach 1:
The patent replaces the physical mask substrate with a spatial light modulator that generates mask patterns through digital control. The spatial light modulator creates optical copies of patterns dynamically, eliminating the need for physical mask fabrication while maintaining exposure precision through controlled light modulation.
Solution Approach 2:
The patent substitutes the mechanical mask substrate handling system with an optical modulation system. Instead of physically manufacturing and positioning mask substrates, the system uses electrically controlled spatial light modulators to generate patterns, replacing mechanical fabrication with optical-electrical control.
2Productivity
If the substrate is scanned at high speed for high throughput, then productivity increases, but exposure precision decreases
Solution Approach 1:
The patent employs dynamic pattern generation through the spatial light modulator that can adapt and update patterns in real-time during substrate scanning. The system synchronizes the scanning motion with dynamic light modulation, allowing the pattern to be generated and projected simultaneously with substrate movement, thus maintaining precision at high speeds.
Solution Approach 2:
The patent implements continuous scanning exposure where the substrate moves continuously through the exposure field while the spatial light modulator continuously generates and projects patterns. This eliminates the need for discrete stop-and-expose cycles, maintaining continuous useful action that achieves both high throughput and precision through synchronized motion and modulation.
3Manufacturing precision
If more pulses are used for exposure, then exposure precision improves, but exposure time increases
Solution Approach 1:
The patent changes the parameters of light delivery by using high-intensity, precisely controlled light pulses from the spatial light modulator. Instead of using multiple low-intensity pulses, the system delivers fewer but more intense and precisely timed pulses, changing the temporal and intensity parameters to achieve the same or better exposure precision with reduced total exposure time.
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
This configuration enables high-throughput and high-precision exposure with a reduced number of pulses, improving the efficiency and accuracy of pattern projection onto substrates, thereby enhancing the overall performance of the exposure apparatus.
Implementation Method 1
a spatial light modulator including light modulation elements that are two-dimensionally arranged; an illumination unit configured to irradiate the spatial light modulator with illumination light
Implementation Method 2
a projection unit configured to guide the illumination light from the light modulation elements to respective light irradiation areas that are two-dimensionally arranged
Data Source
AI summary
An exposure apparatus includes a substrate holder configured to hold a substrate and move, a module including a spatial light modulator having light modulation elements that are two-dimensionally arranged, an illumination unit irradiating the spatial light modulator with illumination lights, and a projection unit guiding the illumination light from the light modulation elements to respective light irradiation areas that are two-dimensionally arranged on the substrate in first and second directions, and a control unit configured to drive the substrate holder in a scanning direction, wherein the light modulation elements are two-dimensionally arranged to be inclined at a predetermined angle θ (0°<θ<90°) with respect to the scanning direction and a non-scanning direction orthogonal to the scanning direction, and when a predetermined region of the substrate is exposed, the control unit scans the substrate holder at such a speed that spot positions are arranged in a staggered arrangement.