Charged Particle Beam Inspection Apparatus for Multi-Mode Defect Detection
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Solution Overview
Problem
Conventional inspection techniques, such as optical and SEM, are limited in their ability to perform multiple types of defect inspections, including pattern defect, foreign material, and multilayer defect inspections, due to differences in detection methods and mechanisms, leading to inefficiencies and increased space requirements.
Innovation Solution
A charged particle beam inspection method and apparatus that uses a single device to perform multiple inspections by adjusting beam energies and incorporating a charge removal process, allowing for pattern defect, foreign material, and multilayer defect inspections with a projection-type electron beam system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple types of inspection apparatuses (optical, SEM) are used to perform different defect inspections, then detection accuracy for various defect types is improved, but device complexity and space requirements increase
Solution Approach 1:
The inspection apparatus is designed to perform multiple types of inspections (pattern defect inspection, foreign material inspection, and in-multilayer defect inspection) using a single charged particle beam system. By adjusting beam energy levels, the same apparatus can detect different defect types that previously required separate specialized devices, thereby reducing overall system complexity while maintaining detection accuracy across all defect types.
Solution Approach 2:
The system changes the energy parameter of the charged particle beam to enable different inspection modes. By varying beam energy, the apparatus can optimize detection for surface defects versus subsurface defects, allowing one device to replace multiple specialized inspection tools while maintaining the detection precision needed for each defect type.
2Measurement precision
If an SEM type inspection apparatus is used for particle inspection with pixel size 1/2 to 1/3 of a particle, then detection accuracy is improved, but inspection time increases significantly
Solution Approach 1:
The system dynamically adjusts the beam diameter based on the inspection mode and defect size. For particle inspection, the beam diameter is optimized to balance resolution requirements with inspection speed, rather than using a fixed small pixel size. This dynamic adjustment allows the apparatus to maintain sufficient detection accuracy while significantly improving inspection throughput compared to conventional SEM approaches.
3Productivity
If optical inspection apparatus is used for high S/N and high rate inspection, then productivity is improved, but measurement precision decreases for defects 50 nm or less
Solution Approach 1:
The system replaces optical inspection with a charged particle beam (electron beam) inspection system. Charged particles have much shorter wavelengths than visible light, enabling detection of defects 50 nm or less while maintaining high inspection rates. This substitution of the inspection mechanism allows simultaneous achievement of high precision for fine defects and high productivity.
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 efficient performance of multiple inspection types with improved throughput and reduced space requirements by using a single apparatus, enhancing detection sensitivity and accuracy across various defect sizes and locations.
Implementation Method 1
An SEM type inspection apparatus is configured to scan a sample with an electron beam as a charged particle beam
Implementation Method 2
An optical inspection apparatus irradiates laser or other light onto a sample, and detects light scattered by particles
Data Source
AI summary
A charged particle beam inspection apparatus comprises: an electron gun for irradiating an electron beam onto a sample; a detector for detecting a signal obtained from the sample; an image processor for forming an image from the signal obtained from the detector, and an energy controller for controlling the beam energy of the electron beam to be irradiated onto the sample. An identical charged particle beam inspection apparatus carries out a plurality of types of inspections. An inspection apparatus of a projection type may be applied thereto. A pattern defect inspection, a foreign material inspection, and an inspection for a defect in a multilayer are carried out. Beam energies E1, E2, and E3 in those inspections have a relation E1>E2 and E3>E2. Charge removal is performed in a transport chamber or other vacuum chamber before an inspection.