Multi-Beam Objective Lens Layout for Precise Defect Inspection
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Solution Overview
Problem
Current charged-particle inspection tools face challenges in improving throughput and image quality due to aberrations in multi-beam systems, which affect the detection of micro and nano-scale defects on semiconductor substrates, leading to reduced yield and increased costs in IC chip manufacturing.
Innovation Solution
A charged particle assessment tool with an objective lens that projects multiple charged particle beams through beam apertures and integrates sensor units adjacent to these apertures to capture emitted charged particles, reducing aberrations and enhancing detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple charged particle beams are used to increase inspection throughput, then productivity improves, but aberrations occur that reduce measurement precision
Solution Approach 1:
The patent divides the inspection system into multiple independent beam channels, each with its own objective lens and sensor unit. This segmentation allows parallel inspection of different regions, improving throughput while maintaining precision in each individual beam path. The multi-beam configuration enables simultaneous detection across multiple areas without the aberrations affecting all beams collectively.
Solution Approach 2:
Each beam aperture and sensor unit is optimized for its specific local function. The objective lens is designed with specific apertures positioned to minimize aberrations for each beam path, and sensor units are placed adjacent to corresponding apertures for optimal signal capture. This local optimization ensures that each beam maintains high measurement precision while contributing to overall increased productivity.
2Measurement precision
If sensor units are integrated adjacent to beam apertures in the objective lens, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges the sensor units directly with the objective lens structure, positioning them adjacent to the beam apertures. This integration eliminates the need for separate detection systems and reduces the number of optical paths required. By combining these functions into a unified structure, the patent achieves high measurement precision while managing device complexity through functional integration rather than addition.
Solution Approach 2:
The objective lens serves multiple functions: it focuses the charged particle beams, defines the beam apertures, and houses the sensor units for detection. This multi-functionality reduces the need for separate components, thereby improving measurement precision through integrated design while avoiding proportional increases in device complexity. The sensor units are designed to work in conjunction with the lens structure rather than as separate additions.
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 solution improves the detection of micro and nano-scale defects, increasing throughput and image quality, thereby enhancing the yield and reducing costs in semiconductor manufacturing by minimizing operator intervention and improving defect identification.
Implementation Method 1
a primary electron beam of electrons at a relatively high energy is targeted with a final deceleration step in order to land on a sample at a relatively low landing energy. The beam of electrons is focused as a probing spot on the sample.
Implementation Method 2
The interactions between the material structure at the probing spot and the landing electrons from the beam of electrons cause electrons to be emitted from the surface, such as secondary electrons, backscattered electrons or Auger electrons. The generated secondary electrons may be emitted from the material structure of the sample.
Data Source
AI summary
A charged particle assessment tool including: an objective lens configured to project a plurality of charged particle beams onto a sample, the objective lens having a sample-facing surface defining a plurality of beam apertures through which respective ones of the charged particle beams are emitted toward the sample; and a plurality of capture electrodes, each capture electrode adjacent a respective one of the beam apertures, configured to capture charged particles emitted from the sample.