Lithographic Mask Evaluation via Triggered Illumination
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Solution Overview
Problem
In the production of electronic components using optical microlithography, errors in photo mask substrates due to inadequate calibrations or disturbances like vibrations and thermal instabilities lead to manufacturing errors, affecting the performance, functionality, and reliability of electronic components.
Innovation Solution
An evaluation system comprising an optical arrangement with a focal point at a target position on the substrate, an image capturing device, an illumination unit, and a control unit that performs an imaging sequence with image and illumination trigger signals to evaluate the substrate accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional continuous illumination and image capturing is used, then the substrate can be continuously monitored, but image quality deteriorates due to vibrations and thermal instabilities
Solution Approach 1:
The patent implements periodic illumination and periodic image capturing using trigger signals. The illumination unit is activated only during specific time windows when the substrate is stable, and the image capturing device captures images only during these stable periods. This periodic action eliminates the negative effects of continuous operation during unstable periods, thereby improving both image quality and evaluation reliability.
2Manufacturing precision
If high-resolution evaluation is performed to detect early errors, then manufacturing precision improves, but production time increases
Solution Approach 1:
By using periodic illumination and periodic image capturing triggered only during stable periods, the system achieves high-resolution evaluation without continuous operation. This allows rapid acquisition of quality images during stable windows, maintaining high productivity while ensuring manufacturing precision through selective high-resolution capture only when conditions permit.
Solution Approach 2:
The system monitors substrate stability in advance and triggers illumination and image capturing only when stability conditions are met. This preliminary assessment of substrate stability allows the system to prepare for high-resolution evaluation at the optimal moment, ensuring both precision and efficiency without unnecessary delays.
3Illumination intensity
If continuous illumination is applied, then the substrate is constantly visible, but energy consumption increases and image quality decreases due to thermal effects
Solution Approach 1:
The illumination unit operates periodically rather than continuously, activated only during stable time windows triggered by the control unit. This periodic illumination maintains substrate visibility during critical evaluation periods while minimizing overall energy consumption and preventing thermal accumulation that would degrade image quality and substrate stability.
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
The system provides high-resolution and reliable evaluation of substrates, enabling early detection of errors, improving calibration of production processes, and ensuring the accuracy of electronic components manufactured.
Implementation Method 1
an illumination unit (140) configured to illuminate the target position (112) of the substrate (110) via the at least one optical arrangement (120)
Implementation Method 2
The present invention allows evaluation of a substrate by at least one of light reflection and light transmission analysis
Implementation Method 3
The present invention allows evaluation of a substrate by at least one of light reflection and light transmission analysis
Data Source
Figure 1A~1C
Figure 2
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AI summary
An evaluation system is provided for evaluating a substrate. The evaluation system comprises at least one optical arrangement configured to have a focal point at a target position of the substrate, an image capturing device configured to capture an image of the target position of the substrate via the at least one optical arrangement, an illumination unit configured to illuminate the target position of the substrate via the at least one optical arrangement, and a control unit configured to perform an imaging sequence. The imaging sequence comprises an image trigger signal and an illumination trigger signal, wherein the control unit is configured to send the image trigger signal to the image capturing device and the illumination trigger signal to the illumination unit. The image capturing device is configured to receive an image trigger signal and capture an image based on the image trigger signal. The illumination unit is configured to receive the illumination trigger signal and to illuminate the substrate based on the illumination trigger signal.