LED Array Illumination Control for Semiconductor Exposure

The illumination system is segmented into multiple independent light sources (e.g., 9 LEDs arranged in a 3×3 matrix) instead of using a single light source. Each light source can be independently controlled to illuminate different regions or provide different illumination angles, enabling adaptation to various pattern types including contact hole arrays, isolated contact holes, and line-space patterns without requiring mechanical changes to the illumination system.

The illumination system transitions from a static single light source to a dynamic multi-light-source configuration where the intensity and on/off state of each individual light source can be dynamically adjusted based on the pattern being exposed. This dynamic control allows the same illumination system to optimally serve multiple pattern types by activating appropriate subsets of light sources.

The patent replaces mechanical shutters and aperture stops with an electronically controlled array of semiconductor light sources. Instead of mechanically adjusting illumination shapes by moving shutters or rotating aperture wheels, the system electronically turns individual LEDs on or off to create the desired illumination pattern. This eliminates mechanical adjustment time and enables rapid switching between different illumination modes, significantly improving productivity while maintaining ease of operation through electronic control.

The system employs periodic or pulsed activation of individual light sources rather than continuous illumination from a single source. By selectively turning on specific LEDs in the array according to the exposure requirements, the system achieves different illumination shapes and angles without mechanical movement, enabling fast reconfiguration between exposures of different pattern types.

The illumination is segmented into multiple independent light sources distributed across the illumination field. Each light source contributes to illuminating a specific region or angular range, and their combined effect produces uniform illumination across the entire substrate. This segmentation allows better spatial distribution of light energy, improving uniformity without requiring excessive energy from a single source.

Multiple semiconductor light sources are merged in their illumination output to achieve uniform coverage across the substrate. By combining the light from several LEDs positioned at different locations and angles, the system creates a superposition of illumination fields that results in uniform intensity distribution, eliminating hot spots and dark regions that would occur with a single light source.

The patent employs asymmetric illumination patterns by selectively activating specific light sources in the array rather than using symmetric illumination from a single source. Different subsets of LEDs are activated to create asymmetric illumination angles and distributions that are optimized for specific pattern types. This asymmetric multi-angle illumination enhances both the depth of focus and the resolution by providing constructive interference patterns that improve image quality without the trade-off inherent in simply increasing DOF.

The system changes illumination parameters (intensity, angle, distribution) by selecting different combinations of active light sources rather than physically changing optical components. By dynamically adjusting which LEDs are on and their relative intensities, the system can optimize the illumination conditions for each exposure, achieving both high depth of focus and high resolution simultaneously through parameter optimization rather than component changes.