Electrostatic Deflectors for Beam Alignment in Miniature SEMs
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Solution Overview
Problem
Miniature electron or ion beam columns face challenges in aligning the electron/ion source optical axis to the extraction electrode and limiting aperture, requiring micron-scale accuracy due to thermal-induced motion and manufacturing errors, with previous mechanical alignment solutions being expensive, unreliable, and bulky.
Innovation Solution
Incorporating one or more electrostatic deflectors into the column source stack to align the beam with column elements, providing primary and secondary blanking functions, and compensating for manufacturing errors, utilizing microfabricated components and high-density interconnection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical alignment methods (ultra-high vacuum compatible stage or flexure) are used to align the source optical axis to column elements, then alignment accuracy can be achieved, but the system becomes expensive, unreliable, and bulky
Solution Approach 1:
The patent replaces mechanical alignment systems (stages or flexures) with electrostatic deflectors that use electric fields to steer the charged particle beam. This substitution eliminates the need for complex mechanical alignment components while achieving the required micron-scale alignment accuracy through electrical control of beam position.
Solution Approach 2:
The electrostatic deflector acts as an intermediary element between the source and column elements. Instead of mechanically aligning the source to the column, the deflector mediates the beam path, allowing dynamic adjustment of the beam trajectory to compensate for misalignments without requiring precise mechanical positioning.
2Productivity
If the source is heated during operation to maintain electron emission, then beam current is maintained, but thermal-induced motion causes shifts that degrade performance or prevent operation
Solution Approach 1:
The patent implements dynamic beam steering using electrostatic deflectors that can respond in real-time to thermal drift. As the source heats up and moves, the deflector dynamically adjusts the beam position to maintain proper alignment with column elements, allowing continuous operation without performance degradation.
Solution Approach 2:
The system uses feedback control where the electrostatic deflector continuously compensates for thermal-induced source motion. By monitoring beam position and adjusting deflector voltages accordingly, the system maintains stable operation despite thermal effects during prolonged electron emission.
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
Achieves precise beam alignment and high-performance operation by correcting for thermal and manufacturing-induced misalignments, enabling GHz electronics and improving spot size and resolution in miniature scanning electron microscopes.
Implementation Method 1
incorporating one or more electrostatic deflectors into the column source stack
Implementation Method 2
the source deflectors can provide primary blanking and secondary blanking functions
Data Source
AI summary
A charged particle beam column package includes an assembly (e.g., comprising a plurality of layers, which can have a component coupled to one of the layers), and at least one deflector between an extractor and aperture of the assembly. Further, at least one of the layers has interconnects thereon.