Substrate Foreign Matter Inspection Using Variable Irradiation Area
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing foreign matter inspection methods struggle to distinguish between scattered light from substrate structures like marks and patterns and scattered light from foreign matter without increasing costs or complexity through additional detectors and control systems.
Innovation Solution
A foreign matter inspection apparatus that adjusts the irradiation area on a substrate using a change mechanism to differentiate between scattered light from patterns and foreign matter by comparing light intensity at different spot diameters, utilizing a light projector, light receiver, and control unit to detect foreign matter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a polarizing element and multiple detectors are used to separate scattered light into P-polarized and S-polarized light components, then foreign matter detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the necessary detection function by using a single detector instead of multiple detectors. The system projects light at multiple incident angles and uses one detector to receive scattered light, eliminating the need for complex polarizing elements and multiple detectors while maintaining foreign matter detection capability.
Solution Approach 2:
The single detector is designed to perform multiple functions by receiving scattered light from different incident angles. The detector universally handles detection across various angles without requiring separate specialized detectors for different polarization components.
2Measurement precision
If multiple detectors with synchronous operation are configured to compare P-polarized and S-polarized light intensity, then foreign matter detection accuracy is improved, but control system complexity increases
Solution Approach 1:
The patent removes the complex synchronous operation control system by using a single detector. Instead of coordinating multiple detectors to compare polarization components simultaneously, the system uses one detector to sequentially measure scattered light at different incident angles, eliminating the need for complex timing and coordination control.
3Measurement precision
If scattered light distribution on the pupil plane is used to distinguish foreign matter from substrate structures, then detection capability is improved, but the method fails for aperiodic structures
Solution Approach 1:
The patent changes the detection parameter from spatial distribution patterns on the pupil plane to incident angle variations. By measuring scattered light intensity at multiple different incident angles and comparing the relationships between these measurements, the system can distinguish foreign matter from both periodic and aperiodic substrate structures without relying on regular pattern distribution.
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
Effectively distinguishes between scattered light from substrate structures and foreign matter without requiring complex detectors or control systems, enhancing detection accuracy and reducing costs.
Implementation Method 1
irradiates a substrate with light and detects a foreign matter by receiving scattered light from the foreign matter
Implementation Method 2
an electron generated at a photocathode by incident light is accelerated by a high voltage and then collides with a plurality of stages of dynodes that generate a secondary electron
Data Source
AI summary
A inspection apparatus for detecting a foreign matter on a substrate on which a pattern is formed includes a detection unit including a light projector for projecting light on a surface of the substrate and a light receiver, a change mechanism for changing an area of the light projected by the light projector to a first area and a second area that is smaller than the first area without changing a light amount, and a control unit for detecting the foreign matter based on a first light amount received by the light receiver in a case where the light is projected in the first area on the surface of the substrate and a second light amount received by the light receiver in a case where the light is projected in the second area on the surface of the substrate.