Micromirror Exposure Reticle Layout for Higher-Resolution Maskless Imaging
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Solution Overview
Problem
Existing digital micromirror devices (DMDs) in maskless exposure units are limited by resolution and require complex calculations, leading to inefficient exposure processes and potential blurring due to relative movement between the optical system and the layer being exposed.
Innovation Solution
The design of micromirrors with superimposed intensity profiles and the use of multiple light sources allows for improved exposure resolution and simultaneous exposure at different focus depths, combined with dynamic light distribution and real-time correction mechanisms to minimize blurring and enhance positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light source is used to illuminate the DMD, then the device complexity is reduced, but the exposure resolution and speed are limited
Solution Approach 1:
The invention divides the illumination task into multiple independent light sources, each illuminating specific regions of the DMD. This segmentation allows parallel exposure of different areas, increasing overall throughput and resolution without requiring a single complex high-power source
Solution Approach 2:
Multiple light sources are combined to illuminate different portions of the DMD simultaneously. The beams from multiple sources are merged in the optical path to create a composite illumination pattern that achieves higher resolution and faster exposure than a single source could provide
2Area of stationary object
If the optical system and layer move relative to each other during exposure, then the exposure area can be covered, but motion blur occurs reducing image quality
Solution Approach 1:
The system pre-calculates and pre-positiones multiple light sources and DMD regions to account for the relative motion that will occur during exposure. By planning the illumination pattern in advance to compensate for motion, the system achieves sharp images despite the moving components
Solution Approach 2:
The invention implements dynamic control where the illumination pattern from multiple light sources is adjusted in real-time to track and compensate for the relative motion between the optical system and the layer. This dynamic adaptation maintains image quality throughout the exposure process
3Ease of operation
If micromirrors use non-superimposed intensity profiles, then the positioning is simpler, but the exposure homogeneity is poor
Solution Approach 1:
Each light source is assigned to illuminate specific local regions of the DMD with tailored intensity profiles. By optimizing the illumination characteristics for each local area rather than using a uniform approach, the system achieves homogeneous exposure across the entire surface while maintaining relatively simple positioning control
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 approach enables higher-resolution, faster exposure processes without masks, allowing for broader light spectrum utilization and simultaneous exposure at multiple depths with reduced motion blur and improved overlay accuracy.
Implementation Method 1
the optical system is designed such that a superposition of mirror intensity profiles of neighboring micromirrors to a grid intensity profile of the exposure grid as the sum of the mirror intensity profiles of each illuminated pixel of the exposure grid takes place
Implementation Method 2
at least two light sources for generating at least two light beams, wherein the light beams of the light sources are in particular superimposed, combined, or mixed
Data Source
Figure 1~2
Figure 3
Figure 4a~5b
AI summary
The present invention relates to a method for exposing a light-sensitive layer (9) using an optical system (8), wherein at least one light beam (6, 6') is generated by at least one respective light source (7) and pixels (23) in an exposure reticle (24, 24', 24", 24"') are exposed by at least one micro-mirror apparatus (1) comprising a plurality of micro-mirrors (3), each pixel being exposed with a mirror intensity profile (22, 22', 22"). The method is characterised in that mirror intensity profiles (22, 22', 22") of neighbouring micro-mirrors (3) are superimposed to form a reticle intensity profile of the exposure reticle (24, 24', 24", 24"'), this profile representing the sum of the mirror intensity profiles (22, 22', 22") of each exposed pixel (23) of the exposure reticle (24, 24', 24", 24"'). The present invention also relates to a device for exposing a light-sensitive layer (9) using an optical system (8) comprising: at least one light source (7) for generating at least one light beam (6, 6'); at least one micro-mirror apparatus (1) comprising a plurality of micro-mirrors (3), each micro-mirror (3) being used to expose a pixel (23) of an exposure reticle (24, 24', 24", 24"') with a mirror intensity profile (22, 22', 22"), wherein the optical system (8) is designed to superimpose mirror intensity profiles (22, 22', 22") of neighbouring micro-mirrors (3) to form a reticle intensity profile of the exposure reticle (24, 24', 24", 24"'), this profile representing the sum of the mirror intensity profiles (22, 22', 22") of each exposed pixel (23) of the exposure reticle (24, 24', 24", 24"').