LED Light Source Arrangement for Photolithography
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Solution Overview
Problem
Photolithography exposure systems face challenges in achieving high illumination intensity with a compact footprint due to the lower luminous flux of LEDs compared to gas discharge lamps, requiring larger LED arrangements that reduce available space.
Innovation Solution
A light source arrangement using at least three LEDs with different wavelengths, combined through a beam splitting unit with wavelength-selective reflecting faces, allowing for the addition of illumination intensities similar to gas discharge lamps, while maintaining a compact design by using LEDs that emit light in specific wavelengths adapted to the photoresist, and incorporating integrator optics for enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If LEDs are used as light source to achieve compact design, then footprint is reduced, but illumination intensity becomes insufficient
Solution Approach 1:
The patent combines multiple LED light sources with different wavelengths (i-line, h-line, g-line) into a single illumination system through a beam splitting unit. By merging the light outputs of three separate LEDs, the system achieves illumination intensity comparable to conventional gas discharge lamps while maintaining the compact footprint advantage of LEDs.
2Illumination intensity
If multiple LEDs are used to achieve comparable illumination intensity, then illumination intensity is improved, but device complexity and footprint increase
Solution Approach 1:
The patent arranges three LED light sources around the beam splitting unit in a spatial configuration that optimizes light combining efficiency. The beam splitting unit uses reflecting faces at specific angles (45 degrees) to redirect light from multiple sources into a single output path, effectively managing the complexity of multiple LEDs through clever spatial and optical design.
3Adaptability or versatility
If complete emission spectrum of gas discharge lamp is generated by LEDs, then spectral coverage is improved, but device complexity and cost increase
Solution Approach 1:
Instead of attempting to generate the complete emission spectrum of a gas discharge lamp, the patent extracts only the three most critical wavelength bands (i-line at 365 nm, h-line at 405 nm, and g-line at 436 nm) that are essential for photolithography exposure. This selective approach maintains spectral adequacy while significantly reducing system complexity compared to using full-spectrum sources.
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 solution achieves high illumination intensity comparable to gas discharge lamps with a smaller footprint, optimizing space usage and exposure quality by selectively reflecting and combining LED light spectra, thereby enhancing the efficiency and cost-effectiveness of the photolithography exposure system.
Implementation Method 1
a beam splitting unit comprising at least three inputs, one output, and at least two reflecting faces, wherein an input is assigned to each light source and each reflecting face, wherein the reflecting face reflects the light into the output
Data Source
AI summary
A light source arrangement for a photolithography exposure system comprises at least three light sources with different wavelengths, and a beam splitting unit comprising at least three inputs, one output, and at least two reflecting faces. An input is assigned to each light source and each reflecting face. The reflecting face reflects light that is emitted from the light source assigned to a corresponding input thereof into the output. The three light sources are arranged on three different sides around the beam splitting unit.