Belt Contamination Detection via Optical Scattering
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Solution Overview
Problem
Current methods for determining the degree of contamination on thin, film-like surfaces of belts used in semiconductor production, such as organic LEDs, are inadequate for detecting small particles and measuring layer thickness with high accuracy and speed, especially in in-situ or in-line production processes.
Innovation Solution
A device utilizing line-shaped illumination and scattered light measurement with adjustable beam shaping and telescopic arrangements for precise detection of particles and layer thickness, allowing for in-situ monitoring of contamination and thickness measurement with high spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional cameras are used to observe surfaces, then the device is simple and easy to operate, but the resolution is insufficient to detect particles smaller than 10 μm
Solution Approach 1:
The patent replaces conventional mechanical camera systems with an optical scattering measurement system. Instead of using cameras to directly image particles, the invention uses light scattering principles to detect particles through their optical interaction with the surface, enabling detection of sub-10 μm particles without requiring high-resolution imaging hardware.
Solution Approach 2:
The patent introduces light scattering as an intermediary mechanism between the measurement system and particles. By measuring the scattering of light from particles on the surface, the system can indirectly detect particle presence and size without requiring direct optical imaging, thus achieving high resolution with simpler equipment.
2Measurement precision
If point-shaped measurement methods are used to achieve high resolution, then particle detection precision is improved, but the measurement speed decreases and in-situ monitoring becomes impossible
Solution Approach 1:
The patent divides the surface into multiple measurement zones along the feed direction. By using a line-shaped illumination beam that scans across the surface, the system can simultaneously measure multiple points along the beam path, effectively segmenting the measurement process into parallel detection zones that maintain high resolution while enabling continuous in-situ monitoring.
Solution Approach 2:
The patent transitions from point-shaped measurement to line-shaped measurement by extending the illumination beam in the transverse direction. This dimensional change allows the system to measure multiple points simultaneously along the line, dramatically increasing measurement speed while maintaining the high resolution achieved through optical scattering detection.
3Productivity
If the line width of the illumination beam is increased to cover more surface area, then the examination speed is improved, but the spatial resolution for detecting small particles decreases
Solution Approach 1:
The patent employs a dynamically adjustable line width for the illumination beam. The line width can be varied to match the specific detection requirements: narrower lines for high-resolution particle detection and wider lines for rapid surface scanning. This dynamic adjustment allows the system to optimize the balance between examination speed and spatial resolution for different measurement tasks.
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 effective detection of particles as small as 0.1 μm and layer thickness measurement with accuracy better than 2 nm, facilitating real-time monitoring and ensuring surface cleanliness for subsequent manufacturing steps.
Implementation Method 1
a detector unit for detecting illumination radiation scattered on the band-shaped sample
Implementation Method 2
the beam shaping unit having at least one telescopic arrangement for beam expansion of the illumination radiation in the feed direction, and wherein at least one of the optical elements of the telescope arrangement has an adjustable focal length for adjusting the line width
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a device (1a) for determining a layer thickness (d) of a belt (8) moved along a feed direction comprising: a movement unit (9) for moving the belt (8) along the feed direction, a light generation unit (2a to 2c) for generating light beams (3), a beam shaping unit (4) arranged downstream of the light generation unit (2a to 2c) for shaping at least one strip-shaped light beam (7) for linear illumination of the belt (8) transversely to the feed direction, a detector unit (5) for detecting light beams (R) reflected by and/or transmitted to the belt (8), and an evaluation unit (6) for determining the layer thickness (d) using the detected light beam (R). The device (1a) can also be used for determining a contamination level of a surface of the belt contaminated by particles by detecting light beams scattered by the belt (8).