SEM Inspection with Selective Charging for Electrical Failure Detection
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Solution Overview
Problem
Current methods for inspecting semiconductor devices are inadequate in detecting failure, particularly electrical failure, as they lack the capability for quantitative analysis and efficient inspection time management, and do not adapt well to varying inspection orders or failure types.
Innovation Solution
A method involving a scanning electron microscope (SEM) that uses a charging electron beam to divide the inspection region into charging and non-charging areas, followed by scanning with a secondary electron beam to detect secondary electrons, allowing for targeted inspection and reduced inspection time by alternating the electron beam irradiation between inspection targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charging electron beam is irradiated to all inspection targets, then electrical failure detection capability is improved, but inspection time increases
Solution Approach 1:
The inspection region is divided into a charging region and a non-charging region. The charging electron beam is irradiated only to the charging region to charge inspection targets, while the non-charging region is skipped. This segmentation allows selective charging of only those targets that require it for failure detection, reducing overall inspection time while maintaining detection capability.
Solution Approach 2:
Instead of charging all inspection targets uniformly, the method applies partial charging only to the charging region. This partial action is sufficient to detect electrical failures in charged targets while avoiding the time penalty of charging every target in the inspection region.
2Productivity
If the inspection region is divided into charging and non-charging regions, then inspection efficiency is improved, but device complexity increases
Solution Approach 1:
The inspection region is segmented into charging and non-charging regions based on the arrangement of inspection targets. This segmentation is implemented through control of the electron beam irradiation pattern, allowing efficient inspection by treating different regions differently without requiring additional physical hardware.
Solution Approach 2:
The inspection method dynamically adjusts the electron beam irradiation strategy based on the detected arrangement of inspection targets. The system identifies alternating columns of targets and applies charging only to specific columns, making the inspection process adaptive and efficient while maintaining manageable complexity through software/control logic.
3Measurement precision
If electron beam irradiation is alternated between first and second targets, then quantitative analysis of failure is improved, but measurement precision challenges arise
Solution Approach 1:
Different inspection targets are treated with different electron beam irradiation strategies. First targets in alternating columns are charged with the charging electron beam, while second targets are not charged. This creates local quality differences that enable quantitative analysis of electrical failures by comparing signals from charged and uncharged targets.
Solution Approach 2:
Instead of uniformly charging all targets and trying to detect variations, the method inverts the approach by charging only alternating columns. This creates a deliberate pattern of charged and uncharged targets, making it easier to detect electrical failures through the contrast in their electrical states and secondary electron emissions.
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 enables effective detection of semiconductor device failures, including electrical shorts, with quantitative analysis and optimized inspection time, while adapting to different failure types and inspection orders, improving the overall efficiency of the inspection process.
Implementation Method 1
charging an inspection region of a semiconductor device using a charging electron beam
Implementation Method 2
detecting secondary electrons emitted from the inspection region by the scanning electron beam
Data Source
AI summary
A method of inspecting a semiconductor device includes charging an inspection region of a semiconductor device using a charging electron beam, and scanning the inspection region using a scanning electron beam. The charging of the inspection region includes dividing the inspection region into a charging region and a non-charging region, and charging the charging region using the charging electron beam. The scanning of the inspection region includes irradiating the scanning electron beam to the inspection region, and detecting secondary electrons emitted from the inspection region by the scanning electron beam.