Flat Panel Particle Detection Illumination Field Adjustment
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Solution Overview
Problem
Existing particle detection devices for flat panels face issues with particle mirror crosstalk and pattern crosstalk on the lower surface, which degrade the signal-to-noise ratio (SNR) and detection accuracy, particularly when the lower surface is a chrome mask.
Innovation Solution
The method involves adjusting the half width and luminous intensity of the illumination field, as well as the position of the light source and detector, to satisfy specific ratios and angles that minimize particle mirror crosstalk and pattern crosstalk, using formulas such as s<=2h*tan θ−0.5w and i_center/i_edge>(i_min p1/i_max p1_mir)*snr1, to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dark-field scatterometry technique is used for particle detection, then foreign objects on the flat panel can be detected, but particle mirror crosstalk occurs when the lower surface is a chrome mask, degrading detection accuracy
Solution Approach 1:
The patent changes the illumination parameters by adjusting the half width of the illumination field and the luminous intensity distribution (making the center intensity higher than edge intensity). This parameter optimization suppresses particle mirror crosstalk while maintaining detection capability, directly resolving the contradiction between detection accuracy and mirror crosstalk interference
Solution Approach 2:
The patent dynamically adjusts the illumination field characteristics by optimizing the half width and luminous intensity ratio based on the specific detection requirements and panel properties. This dynamic optimization allows the system to adaptively suppress mirror crosstalk while maintaining high detection accuracy
2Reliability
If the lower surface of the flat panel is a chrome mask with patterns, then the panel structure is formed, but pattern crosstalk seriously affects the signal-to-noise ratio of detection signals
Solution Approach 1:
The patent optimizes the illumination field half width and luminous intensity distribution parameters to minimize pattern crosstalk. By carefully controlling these parameters, the system maintains the chrome mask structure while suppressing pattern interference to improve signal-to-noise ratio
Solution Approach 2:
The patent applies non-uniform illumination by making the luminous intensity at the center of the illumination field higher than at the edges. This local quality variation in illumination helps differentiate particle signals from pattern crosstalk, improving the signal-to-noise ratio while preserving panel structure integrity
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 significantly alleviates particle mirror crosstalk and pattern crosstalk, thereby improving the signal-to-noise ratio and detection accuracy of foreign objects on the flat panel.
Implementation Method 1
Light 101 emitted from a radiation light source 10 is incident on a to-be-detected flat panel 40
Implementation Method 2
light 101 emitted from a radiation light source 10 is incident on a to-be-detected flat panel 40 at a particular angle, and then is scattered by foreign objects on the to-be-detected flat panel 40. Scattered signal light 102 enters a detection unit 20
Implementation Method 3
When particles exist on the upper surface of the mask, the chrome layer is equivalent to a mirror, and these particles form virtual images with respect to the chrome layer, which are referred to as mirrored particles
Data Source
AI summary
A method for detecting degree of particulate contamination on a flat panel mainly includes the following steps: illuminating a to-be-detected flat panel (40) by using a light source module (10), to form an illumination field; adjusting a half width of the illumination field; adjusting a luminous intensity at a center of the illumination field and a luminous intensity at an edge of the half width of the illumination field; adjusting a light intensity and a position of the light source, as well as a position of a detector (20); and acquiring signals from foreign objects on the flat panel by using the detector (20). This method greatly alleviates particle mirror crosstalk and crosstalk of patterns on the lower surface of the flat panel, and improves the SNR, thus enhancing the accuracy in detection of foreign objects on the flat panel.