Foreign Substance Inspection Apparatus with Dual Detection Angles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing foreign substance inspection apparatuses in manufacturing processes, such as those for semiconductor devices, face erroneous detection due to diffracted light from patterns on the reticle, which reduces the accuracy of foreign substance detection.
Innovation Solution
The apparatus includes two detecting units arranged on opposite sides of the irradiating unit, with their light receiving angles adjusted to differentiate between scattered light from foreign substances and diffracted light from patterns, thereby reducing erroneous detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single detecting unit is used to inspect foreign substances on the reticle surface, then the device structure is simple, but erroneous detection occurs due to diffracted light from patterns
Solution Approach 1:
The detection system is segmented into multiple detecting units (first detecting unit and second detecting unit) positioned at different locations. Each detecting unit has its own light receiving system with specific light receiving angles, allowing the system to distinguish between scattered light from foreign substances and diffracted light from patterns by comparing signals from different detection positions.
Solution Approach 2:
The invention adds a spatial dimension to the detection system by positioning detecting units at different locations and angles relative to the irradiating unit. The first detecting unit is positioned to receive scattered light at a first light receiving angle, while the second detecting unit receives light at a second light receiving angle, creating angular differentiation that enables discrimination between foreign substance signals and pattern diffraction signals.
2Ease of operation
If the light receiving angle is not differentiated, then the detection system is simple to operate, but false positives occur from diffracted light
Solution Approach 1:
The invention changes the light receiving angle parameter for different detecting units. The first detecting unit is configured with a first light receiving angle and the second detecting unit with a second light receiving angle, both within specific ranges (30-60 degrees and 60-80 degrees respectively). This parameter differentiation allows the system to reliably distinguish between scattered light and diffracted light while maintaining automated operation through pre-configured angle settings.
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 configuration enhances the accuracy of foreign substance inspection by minimizing false positives from diffracted light, allowing for precise detection of foreign substances on the reticle surfaces.
Implementation Method 1
an irradiating unit (4) which emits irradiating light (45)
Implementation Method 2
If a foreign substance 3 is present in the irradiation region 5, the foreign substance 3 causes scattered light
Implementation Method 3
The imaging lens 71 condenses the scattered light on a line sensor 72
Data Source
AI summary
A foreign substance inspection apparatus includes an irradiating unit and first and second detecting units. The irradiating unit is configured to emit irradiating light to be obliquely incident on a surface to be inspected to form a linear irradiation region on the surface to be inspected. The first and second detecting units are arranged on the same side as that provided with the irradiating unit with respect to the surface to be inspected, and they are configured to detect scattered light caused by a foreign substance on the surface to be inspected. The first and second detecting units are arranged at opposite positions with respect to a plane containing the linear irradiation region.