Exposure Equipment Illuminance Control via Variable Attenuators
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Solution Overview
Problem
Existing exposure apparatuses in photolithography face challenges in achieving precise exposure accuracy, especially with increasing product sizes requiring larger scanning widths, which demands more stringent requirements for exposure control and uniform illumination.
Innovation Solution
The exposure apparatus incorporates a control system, light source system, and multiple illumination systems with variable attenuators and branch energy detectors to adjust illuminance levels in real-time, ensuring precise energy control and matching across projection objective lenses, using light source generators and homogenizing units to maintain uniformity and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a larger scanning width is used to accommodate increasing product sizes, then the processing capacity is improved, but the exposure accuracy deteriorates
Solution Approach 1:
The illumination system is divided into multiple independent illumination units, each with its own energy control mechanism. This segmentation allows each unit to be independently optimized and controlled, maintaining exposure accuracy across the entire large scanning width by managing each segment separately.
Solution Approach 2:
The patent employs real-time energy control by dynamically adjusting illumination parameters (intensity, distribution) across different spatial positions. This parameter adjustment compensates for non-uniformities introduced by the large scanning width, ensuring consistent exposure accuracy throughout the expanded processing area.
2Productivity
If multiple illumination systems are used to increase scanning width, then the processing capacity is improved, but the energy distribution uniformity deteriorates
Solution Approach 1:
Energy detectors are integrated into each illumination unit to provide real-time feedback on energy distribution. The control system uses this feedback information to dynamically adjust the illumination parameters, ensuring uniform energy distribution across all illumination systems even as the scanning width expands.
Solution Approach 2:
The illumination system transitions from static to dynamic control, where illumination parameters can be adjusted in real-time based on detected energy distribution. This dynamic adaptation allows the system to maintain uniformity across multiple illumination units despite variations in their individual outputs.
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 enables improved exposure accuracy, faster energy adjustments, and reduced energy loss while maintaining other performance aspects of photolithography machines, resulting in precise control and enhanced exposure performance.
Implementation Method 1
the branch energy detector configured to detect an illuminance level of a second illumination beam generated in a corresponding one of the illumination systems
Implementation Method 2
the variable attenuator comprises two position-adjustable light shading plates each having a plurality of through-holes, and wherein a transmittance of a corresponding one of the first illumination beams is controlled by adjusting a relative position between the two light shading plates
Implementation Method 3
each of the illumination systems further comprises a light homogenizing unit, the branch energy detector configured to detect an illuminance level of a second illumination beam generated in the light homogenizing unit
Data Source
AI summary
An exposure apparatus and method. The exposure apparatus includes a control system, light source system, plurality of illumination systems and plurality of projection objective lenses. The light source system is configured to emit a plurality of first illumination beams incident on the illumination systems. Each illumination system includes a variable attenuator and branch energy detector. The branch energy detector is configured to detect an illuminance level of a second illumination beam generated in the corresponding illumination system and feed it back to the control system. The control system is configured to adjust the illuminance levels of the second illumination beams in the respective illumination systems by controlling the respective variable attenuators therein. The exposure apparatus and method have improved exposure performance and allow finer and faster energy adjustments, thus enabling precise control and higher exposure accuracy.