Sub-image Array Scanning for Maskless Photolithography
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Solution Overview
Problem
Conventional photolithography systems face challenges with expensive and long lead time for patterned masks, limited productivity due to small image size in direct reduced image methods, and significant noise and alignment errors in point array methods, which affect resolution and efficiency.
Innovation Solution
A novel optical system that projects a divided sub-image array using a spatial light modulation device, microlens arrays, and a computer-controlled system to create a digital image on a substrate, reducing noise and improving alignment requirements, while eliminating the need for traditional masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct reduced image method is used, then system complexity is reduced, but image size on substrate becomes very small causing slow productivity
Solution Approach 1:
The patent divides the single image into multiple sub-images and projects them simultaneously onto different regions of the substrate using an array of projection lenses. This segmentation approach allows parallel processing of multiple image portions, significantly increasing productivity while maintaining system simplicity.
Solution Approach 2:
The patent transitions from projecting a single reduced image to projecting multiple sub-images across a two-dimensional array on the substrate. By utilizing the array dimension of projection lenses, the system expands the imaging capability from one-to-one mapping to one-to-many mapping, thereby increasing throughput.
2Manufacturing precision
If point array method with microlens is used, then focusing resolution is improved, but alignment errors and noise increase significantly
Solution Approach 1:
The patent uses an array of projection lenses where each lens projects a sub-image, dividing the focusing task into multiple independent channels. This segmentation reduces the alignment burden on each individual lens while maintaining high focusing resolution through the collective action of the array.
Solution Approach 2:
The patent combines multiple sub-images from an array of projection lenses to form a complete image on the substrate. By merging the outputs of multiple lenses, the system achieves both high resolution and robustness against individual lens alignment errors, as the overall image quality is averaged across the array.
3Manufacturing precision
If conventional photolithography with patterned masks is used, then manufacturing precision is achieved, but mask cost and lead time increase
Solution Approach 1:
The patent uses a spatial light modulator to generate sub-images digitally, replacing the need for physical patterned masks. The SLM can be rapidly reconfigured to produce different patterns without requiring new mask fabrication, thereby eliminating mask lead time and cost while maintaining pattern accuracy through digital control.
Solution Approach 2:
The patent replaces the mechanical mask system with a spatial light modulator that uses electrical signals to control light modulation. This substitution eliminates the need for physical mask handling, fabrication, and alignment, reducing both time and cost while maintaining or improving pattern precision through digital addressing.
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 enhances resolution, reduces noise, and improves depth of focus, enabling faster and more efficient photolithography processes by projecting a contiguous image on the substrate without the need for expensive masks.
Implementation Method 1
a spatial light modulation device at which a plurality of modulation elements, which respectively change light modulation states thereof in accordance with control signals, are one or two-dimensionally arranged, the spatial light modulation device being for modulating the light beam
Implementation Method 2
the microlens set has at least two microlens arrays. The first microlens array set is for condensing light beams
Implementation Method 3
the second microlens array is for shrinking sub-image size on the substrate, which have been modulated by the modulation elements, at the respective microlens
Data Source
AI summary
An “image writing” and “image reading” system and method for providing a pattern to a subject such as a wafer is provided or an image to an image sensor such as CCD. The system includes a pixel panel, such as a digital mirror device or a liquid crystal display or other SLM, for generating for creating a plurality of sub-image array of the pattern in “image writing” case. The pixel elements are simultaneously divided to a sub-image array on the subject by a lens system. The system also includes a stage for moving, stepping or scanning the pixel panel, relative to the subject so that it can create a contiguous whole image on the subject.