SEM Emission Booster for Ultra-Fast Beam Current Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing scanning electron microscopes (SEMs) lack the capability for ultra-fast beam current adjustment, which hinders the timely identification of voltage contrast defects in integrated circuit components.
Innovation Solution
The implementation of a charged-particle inspection system equipped with an emission booster that irradiates electromagnetic radiation onto the charged-particle source, allowing for ultra-fast boosting and cessation of electron emission, thereby enabling rapid switching between high and low beam currents during scanning operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional beam current adjustment methods are used in SEM, then the system structure remains simple, but the beam current adjustment speed is slow and cannot identify voltage contrast defects timely
Solution Approach 1:
The emission booster pre-irradiates the electron source with electromagnetic radiation (laser) to stimulate excess electron emission before the electron beam scanning begins. This preliminary action prepares a reservoir of excess electrons that can be rapidly drawn upon during voltage contrast defect detection, enabling fast beam current adjustment without mechanical modifications to the source itself
Solution Approach 2:
The patent introduces an emission booster as an intermediary device between the electron source and the electron beam scanning system. This mediator uses electromagnetic radiation to indirectly stimulate electron emission, avoiding direct mechanical or electrical modification of the electron source while achieving rapid beam current control
2Productivity
If beam current is increased to improve scanning speed, then productivity increases, but voltage contrast defects cannot be identified due to lack of beam current variation
Solution Approach 1:
The emission booster operates periodically, alternating between irradiating and non-irradiating states to create periodic variations in beam current. During irradiation periods, excess electrons are generated; during non-irradiation periods, the beam current returns to normal levels. This periodic modulation enables voltage contrast defect identification while maintaining high scanning speed
Solution Approach 2:
The patent changes the electron emission parameter by using electromagnetic radiation to stimulate excess electron emission. This parameter change creates a controllable variation in beam current that enables voltage contrast defect detection without requiring mechanical adjustments to the electron source or scanning system
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 enables the generation of voltage contrast images under different beam currents, allowing for the timely identification of potential voltage contrast defects without the limitations of slower beam current adjustments.
Implementation Method 1
an emission booster configured to irradiate electromagnetic radiation onto the charged-particle source for boosting charged-particle emission
Data Source
AI summary
Apparatuses, methods, and systems for ultra-fast beam current adjustment for a charged-particle inspection system include an charged-particle source configured to emit charged particles for scanning a sample; and an emission booster configured to configured to irradiate electromagnetic radiation onto the charged-particle source for boosting charged-particle emission in a first cycle of a scanning operation of the charged-particle inspection system, and to stop irradiating the electromagnetic radiation in a second cycle of the scanning operation.