Electron Beam Separator Thermal Stabilization
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Solution Overview
Problem
Thermally-induced beam drift in electron beam inspection systems impairs the resolution and throughput of semiconductor manufacturing processes, as existing calibration schemes require constant beam position calibration, making long inspection jobs challenging.
Innovation Solution
An apparatus and method that include an electron beam separator with a ceramic divider, electrostatic plates in an octupole arrangement, separator coil pairs, and a heater coil, where the processor determines the Wien power and heater coil current to create a magnetic field for beam deflection calibration, reducing thermal-induced beam drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a Wien filter is used to separate secondary electrons from the primary beam, then electron collection efficiency is improved, but transverse chromatic aberration in the primary beam increases
Solution Approach 1:
A magnetic field acts as an intermediary between the Wien filter and the primary electron beam. The magnetic field compensates for the transverse chromatic aberration induced by the Wien filter, allowing the Wien filter to separate secondary electrons effectively while maintaining primary beam resolution. The magnetic field serves as a mediating element that corrects the distortion caused by the Wien filter.
2Measurement precision
If constant beam position calibration is performed to maintain beam stability, then beam position accuracy is improved, but inspection throughput decreases
Solution Approach 1:
Thermal stabilization is performed as a preliminary action before beam inspection begins. The system pre-heats and stabilizes the beam separator components to a target temperature, establishing thermal equilibrium beforehand. This preliminary thermal conditioning eliminates the need for constant calibration during inspection, as the stabilized thermal state maintains consistent beam separator performance throughout the inspection process.
3Device complexity
If the electron beam separator operates without thermal stabilization, then device complexity is reduced, but beam drift increases
Solution Approach 1:
The system changes the temperature parameter of the beam separator components from variable to constant by implementing thermal stabilization. A heater coil maintains the components at a target temperature, and this temperature parameter control directly stabilizes the beam separator's magnetic properties, eliminating beam drift without requiring complex mechanical adjustment mechanisms.
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
The solution stabilizes the electron beam separator, maintaining constant power and reducing thermal-induced beam drift, thereby enhancing the system's stability and throughput by compensating for residual magnetic field deflections without impacting constant power mode operation.
Implementation Method 1
the processor determines a heater coil current... The heater coil current can create a magnetic field that causes a beam deflection
Implementation Method 2
a first separator coil pair disposed around the ceramic divider and arranged on opposite sides of the electron beam separator; a second separator coil pair disposed around the ceramic divider
Implementation Method 3
a set of electrostatic plates in an octupole arrangement disposed on the ceramic divider
Data Source
AI summary
These electron beam separator designs address thermally-induced beam drift in an electron-optical system. A heater coil wrapped around the beam separator unit can maintain constant power. Additional coils also can be wrapped around the beam separator in a bifilar manner, which can maintain constant power in the beam separator coils. Wien power can be determined, and then heater coil current can be determined.