Particle Inspection Device Using Dual-Angle Light Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional particle inspection devices fail to accurately distinguish between scattered light from particles and diffracted light from complex patterns on substrates, leading to erroneous detection due to the complexity and density of modern patterns.
Innovation Solution
A particle inspection device with two light detection units, each arranged at different angles relative to the substrate and scanning direction, to differentiate between diffracted light from patterns at specific angles and scattered light from particles, using a compound eye configuration with polarizing plates to enhance discrimination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single light detection unit is used to detect scattered light from particles, then particle detection capability is provided, but diffracted light from patterns at specific angles causes erroneous detection
Solution Approach 1:
The light detection unit is divided into multiple detection units (first light detection unit and second light detection unit), each detecting light from different angular directions. This segmentation allows the system to distinguish between scattered light from particles and diffracted light from patterns by comparing signals from different angles, thereby reducing erroneous detection while maintaining particle detection capability
Solution Approach 2:
The invention introduces an angular dimension to light detection by arranging detection units at different angles (different light reception elevation angles and light reception horizontal angles). This dimensional expansion enables the system to differentiate light sources based on their angular characteristics, resolving the contradiction between detecting particles and avoiding false positives from pattern diffraction
2Reliability
If two light detection units are arranged at different angles to distinguish scattered light from diffracted light, then erroneous detection is reduced, but device complexity increases
Solution Approach 1:
Each light detection unit is designed with multi-functionality, detecting both scattered light from particles and diffracted light from patterns simultaneously. By configuring multiple units at different angles, the system achieves reliable particle detection while inherently filtering out false positives, without requiring additional complex processing components
Solution Approach 2:
The invention combines multiple light detection units into a unified detection system that processes signals from different angles simultaneously. The particle detection unit integrates signals from both the first and second light detection units, merging their capabilities to achieve reliable particle detection while canceling out diffracted light interference through comparative analysis
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 reduces erroneous detection caused by diffracted light from patterns forming specific angles, improving the accuracy of particle detection on substrates with complex patterns.
Implementation Method 1
scattered light due to the particle and scattered light due to a pattern edge
Implementation Method 2
diffracted light from a line-and-space becomes a problem
Data Source
AI summary
The present invention reduces erroneous detection due to diffracted light from a pattern, and provides a particle inspection device that inspects a particle adhering to a substrate on which a pattern is formed, including: a light irradiation unit that linearly scans and irradiate the substrate with a laser beam; a first light detection unit and a second light detection unit that detect light reflected by the substrate; and a particle detection unit that detects the particle based on output signals of the first light detection unit and the second light detection unit, in which the first light detection unit and the second light detection unit are arranged such that a light reception elevation angle α with respect to a surface of the substrate and a light reception horizontal angle β with respect to a scanning direction of the laser beam are different from each other.