Exposure Apparatus Multiple Pattern Alignment via Segmented Illumination
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Solution Overview
Problem
Existing exposure apparatuses face challenges in efficiently performing multiple exposures on substrates due to time-consuming mask exchanges and illumination condition changes, which can lower operational rates and throughput, and require accurate positional adjustments of patterns for producing desired microdevices.
Innovation Solution
An exposure apparatus with an optical system capable of forming images of different patterns in distinct exposure areas and a detecting system for obtaining position information, allowing for precise positional adjustments and efficient multiple exposure processes by moving the substrate in a scanning direction and using reflecting surfaces to guide light beams and detect alignment marks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple exposures are performed by exchanging masks or changing illumination conditions, then different patterns can be formed on the substrate, but the operational rate and throughput are lowered due to time-consuming mask exchange and illumination condition change periods
Solution Approach 1:
The patent divides the exposure field into multiple exposure areas (first exposure area and second exposure area) that can be independently illuminated. Different illumination conditions are applied to different areas simultaneously, allowing multiple patterns to be formed without mask exchange. This segmentation enables parallel processing of different pattern regions, maintaining high throughput while achieving pattern diversity.
Solution Approach 2:
The patent introduces a spatial dimension by creating multiple exposure areas at different positions on the substrate. Instead of changing illumination conditions sequentially for the entire field, the system provides different illumination conditions to different spatial areas simultaneously. This dimensional approach allows multiple patterns to be formed in parallel across the substrate surface.
2Adaptability or versatility
If multiple exposures are performed by exchanging masks or changing illumination conditions, then different patterns can be formed on the substrate, but the time required for mask exchange and illumination condition change increases
Solution Approach 1:
The patent enables continuous exposure operation by eliminating the need to stop the exposure process for mask exchange or illumination condition changes. Multiple illumination conditions are maintained simultaneously in different exposure areas, allowing the substrate to be continuously exposed to different patterns without interruption. This continuity eliminates idle time and maintains constant productive operation.
Solution Approach 2:
By dividing the exposure field into multiple independently controllable exposure areas, the system can maintain different illumination conditions in each area simultaneously. This segmentation allows the exposure process to continue uninterrupted with different patterns being formed in different areas at the same time, eliminating time losses associated with changing conditions.
3Manufacturing precision
If positional adjustment is performed for pattern alignment in multiple exposure, then accurate device formation is achieved, but the complexity of the exposure system increases
Solution Approach 1:
The patent uses alignment marks that are copied or projected along with the main patterns onto the substrate. These alignment marks serve as reference features that can be detected and used for positional adjustment. By incorporating alignment functionality into the pattern projection itself rather than requiring separate alignment systems, the patent achieves accurate positioning without significantly increasing overall system complexity.
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
Enables accurate and efficient positional adjustments between patterns, facilitating high-quality multiple exposures on substrates, thereby improving the productivity and performance of microdevice production.
Implementation Method 1
a first reflecting surface which is arranged in the vicinity of positions optically conjugate with the first exposure area and the second exposure area and which guides the first exposure light beam to the optical element; a second reflecting surface which is arranged in the vicinity of positions optically conjugate with the first exposure area and the second exposure area and which guides the second exposure light beam to the optical element
Implementation Method 2
the detecting system detects the alignment mark on the substrate by irradiating a detection light beam onto the substrate via the optical element from a position disposed between the first reflecting surface and the second reflecting surface
Data Source
AI summary
An exposure apparatus includes a projection optical system which is capable of forming an image of a first pattern in a first exposure area and which is capable of forming an image of a second pattern in a second exposure area, the second pattern being different from the first pattern, and a first detecting system which obtains at least one of position information about the image of the first pattern and position information about the image of the second pattern. A positional relationship between the images of the first and second patterns and a predetermined area on a substrate is adjusted based on a detection result to perform multiple exposure for the predetermined area on the substrate with the images of the first and second patterns. The substrate can be subjected to the multiple exposure efficiently.