Multi-Beam Charged Particle Optics With In-Path Light Irradiation
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Solution Overview
Problem
In semiconductor IC manufacturing, charged particle beam inspection tools face challenges in achieving high throughput and defect detection due to charge accumulation on samples, which affects image quality and requires additional processes like advanced charge control, complicating the inspection process.
Innovation Solution
A charged particle apparatus and method that projects a charged particle multi-beam toward a sample, incorporating a light source to irradiate the sample alongside the electron beam, allowing for improved defect contrast without the need for separate light projection systems, thus simplifying the design and enhancing inspection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate light projection system is used to illuminate the sample for charge control, then the accumulated charges on the sample can be regulated, but the device complexity increases and the inspection process becomes more complicated
Solution Approach 1:
The patent combines the light source with the electron-optical device, merging two separate systems (light projection and electron beam inspection) into a single integrated device. The light source is positioned within the electron-optical device structure, allowing both functions to be performed through one apparatus rather than requiring separate systems.
Solution Approach 2:
The electron-optical device is designed to perform multiple functions: both electron beam projection for inspection and light emission for charge control. The device can switch between or simultaneously perform inspection mode and illumination mode, making it a multi-functional apparatus that eliminates the need for dedicated separate systems.
2Reliability
If a flooding column is provided for flooding the sample with electrons, then charge accumulation can be controlled, but the inspection time increases due to switching between flooding column and SEM inspection column
Solution Approach 1:
The light source and electron beam system are merged into a single integrated device structure. The light source is positioned within the electron-optical device, allowing simultaneous or rapid alternating operation of illumination and inspection functions without requiring physical movement or switching between separate columns.
Solution Approach 2:
The light source is pre-positioned within the electron-optical device structure, ready to illuminate the sample whenever needed. This preliminary arrangement eliminates the time required to move or activate separate illumination systems during the inspection process.
3Measurement precision
If the dimensions of the pattern inspection tool are large, then the inspection capability is sufficient, but it becomes difficult to reach the sample with the light beam
Solution Approach 1:
By integrating the light source within the electron-optical device, the patent eliminates the need for external light projection systems. The light source is positioned at the same location as the electron beam exit, allowing direct illumination of the sample through the same optical path without requiring additional space or complex light beam routing.
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 improves defect contrast and simplifies the inspection process by directly irradiating the sample with light through the electron-optical device, reducing the complexity of light projection and enhancing the detection of micro and nano-scale defects in semiconductor IC manufacturing.
Implementation Method 1
the light source is arranged such that the light (or the light path) is projected along paths of the sub-beams through the charged particle-optical device so as to irradiate at least a portion of the sample
Implementation Method 2
a charged particle source configured to emit a charged particle beam
Data Source
AI summary
A charged particle apparatus, configured to project a charged particle multi-beam toward a sample, comprises: a charged particle source configured to emit a charged particle beam; a light source configured to emit light; and a charged particle-optical device configured to project toward the sample sub-beams of a charged particle multi-beam derived from the charged particle beam; wherein the light source is arranged such that the light is projected along paths of the sub-beams through the charged particle-optical device so as to irradiate at least a portion of the sample.