Beam Blanker Independent Deflection Stages Pulse Control
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Solution Overview
Problem
Current beam blankers for charged particle beams face challenges in generating short pulses with low jitter and high flexibility, particularly in compact designs, due to limitations in pulse duration and pulse repetition rate, which are essential for scanning microscopes and photolithographic mask repair.
Innovation Solution
A beam blanker comprising independent deflection elements with adjustable AC voltages of different frequencies and phases, allowing for precise control of pulse duration and pulse period, thereby breaking the rigid relationship between these parameters and enhancing flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pair of printed circuit boards is used for beam deflection, then the device complexity is reduced, but the pulse duration and pulse repetition rate cannot be independently controlled
Solution Approach 1:
The beam blanker is divided into multiple independent deflection stages, each with its own printed circuit board and control electronics. The first deflection stage controls vertical beam position while the second stage controls horizontal beam position, allowing independent adjustment of pulse duration and pulse repetition rate through separate voltage controls.
Solution Approach 2:
The system uses dynamic voltage control on multiple deflection stages to achieve flexible pulse characteristics. By independently varying the voltage amplitude and frequency on each deflection stage, the system can dynamically adjust pulse duration and pulse repetition rate without mechanical moving parts.
2Volume of moving object
If the beam blanker is designed to be compact, then the distance between deflection plates and stop is reduced, but the achievable pulse duration is limited
Solution Approach 1:
The compact beam blanker uses multiple sequential deflection stages rather than a single large deflection system. This segmentation allows the use of smaller individual components arranged in series, achieving compact overall size while maintaining the ability to generate short pulses through cumulative deflection effect.
Solution Approach 2:
The system introduces a second deflection dimension (horizontal vs vertical) to achieve pulse control. By using orthogonal deflection stages, the system can control pulse characteristics without increasing the linear distance between components, effectively using dimensional expansion to overcome spatial constraints.
3Duration of action of moving object
If high voltage rise rate is used to achieve short pulses, then the pulse duration is reduced, but the device complexity and voltage requirements increase
Solution Approach 1:
The voltage control system is segmented across multiple deflection stages, each handling a portion of the total deflection requirement. This distributes the voltage rise rate demand across several lower-voltage circuits rather than requiring one extremely high-voltage circuit, reducing individual component stress and simplifying overall system design.
Solution Approach 2:
The system uses dynamic coordination of multiple voltage sources to achieve the effective high voltage rise rate needed for short pulses. By synchronizing voltage application across multiple stages, the system achieves rapid beam deflection without requiring any single circuit to handle the full voltage swing independently.
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 enables the generation of short pulses with predefined characteristics, improving the detection bandwidth and flexibility in applications such as scanning microscopes and photolithographic mask repair, while minimizing parasitic pulses and maintaining high beam current intensity.
Implementation Method 1
at least one first and one second deflection element, which are each configured to deflect the particle beam from the beam axis in a first and a second direction, respectively, upon a voltage being present
Data Source
AI summary
The present invention relates to a beam blanker for a scanning particle microscope for blanking a charged particle beam having a beam axis, along which charged particles propagate before entering the beam blanker, wherein the beam blanker comprises: (a) at least one stop having an aperture, through which the charged particle beam can pass; (b) at least one first and one second deflection element, which are each configured to deflect the particle beam from the beam axis in a first and a second direction, respectively, upon a voltage being present; and (c) a deflection controller configured to apply a first AC voltage having a first frequency to the first deflection element and a second AC voltage having a second frequency to the second deflection element, wherein the deflection controller sets a difference frequency between the first and second AC voltages such that pulses of the charged particle beam have a predefined pulse period and during the pulse period outside the pulse duration substantially no charged particles pass through the aperture of the stop.