Aperture Alignment via Incident Direction Control
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Solution Overview
Problem
In multi-beam writing apparatuses, aligning the shaping and blanking aperture members is time-consuming due to the difficulty in disposing a beam deflecting mechanism between them, leading to inefficiencies in aligning the aperture members for optimal beam passage.
Innovation Solution
A method involving an incident direction controller to change the electron beam's incident direction, producing a current distribution map based on detected currents, and moving the aperture members to align them, utilizing an alignment coil and stage control to adjust the positioning and orientation of the shaping and blanking aperture members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a beam deflecting mechanism is disposed between the shaping aperture member and the blanking aperture member to enable alignment, then alignment precision can be improved, but the device complexity increases and the space between aperture members must be increased
Solution Approach 1:
The patent replaces the mechanical beam deflecting mechanism with an electromagnetic field-based alignment method. The incident direction controller uses electromagnetic fields to control the incident direction of charged particle beams, eliminating the need for mechanical deflectors between aperture members. This reduces device complexity while maintaining alignment precision.
Solution Approach 2:
The patent introduces a detector as an intermediary element between the aperture members and the control system. The detector measures beam currents to generate alignment information, serving as a mediator that enables precise alignment without requiring direct mechanical interaction or complex deflecting mechanisms between the aperture members.
2Measurement precision
If the stage holding the aperture members is repeatedly moved and rotated to perform alignment, then alignment can be achieved, but the alignment time increases significantly
Solution Approach 1:
The patent implements a feedback-based alignment control system. The detector continuously measures beam currents, and the control unit uses this feedback information to automatically adjust the incident direction and aperture positions. This closed-loop feedback mechanism achieves precise alignment rapidly without requiring repeated manual stage movements and rotations.
Solution Approach 2:
The alignment system performs self-alignment through automated control. The control unit automatically processes detector signals and adjusts aperture positions based on current distribution maps, eliminating the need for operator intervention and repeated manual stage adjustments, thereby significantly reducing alignment time.
3Productivity
If the space between the shaping aperture member and the blanking aperture member is reduced to increase throughput, then productivity improves, but it becomes difficult to dispose a beam deflecting mechanism for alignment
Solution Approach 1:
The patent replaces mechanical beam deflecting mechanisms with electromagnetic field-based control. The incident direction controller uses electromagnetic fields to adjust beam trajectories, eliminating the need for physical deflectors that would require space between aperture members. This allows reduced spacing while maintaining alignment capability.
Solution Approach 2:
The incident direction controller serves multiple functions: it controls the incident direction of beams, enables alignment between aperture members, and compensates for positioning errors. This multi-functional component eliminates the need for separate beam deflecting mechanisms, allowing reduced space between aperture members while maintaining alignment functionality.
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 significantly reduces alignment time by detecting misalignment through current distribution maps and adjusting the aperture members' positions and orientations, ensuring precise alignment and efficient beam passage.
Implementation Method 1
an alignment coil (20)
Implementation Method 2
a detector (60) detecting a current of the multiple beams passed through the blanking aperture member (40)
Implementation Method 3
an electron beam emitted from an electron gun passes through a shaping aperture member having a plurality of holes, thus forming multiple beams (electron beams)
Data Source
AI summary
In one embodiment, a method of aperture alignment for a multi charged particle beam writing apparatus includes irradiating a shaping aperture member with a charged particle beam while changing an incident direction, detecting a current for each of the incident directions of the charged particle beam, producing a current distribution map based on the incident direction and the current, and moving the shaping aperture member or a blanking aperture member based on the current distribution map to align the shaping aperture member with the blanking aperture member.