Multi-Beam Blanking Shield Structure for Beam Trajectory Accuracy
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Solution Overview
Problem
In multi-beam writing apparatuses, the magnetic field generated by the current flowing through the blanking aperture array substrate causes beam trajectory bending and irradiation position displacement, degrading writing accuracy.
Innovation Solution
The use of high magnetic permeability shield members, such as those composed of permalloy, is implemented to absorb and redirect the magnetic field, preventing it from affecting the beam trajectory and ensuring accurate beam placement on the sample surface. These shield members are strategically positioned around the blanking aperture array substrate and connected via high magnetic permeability materials to effectively shield the magnetic field and maintain beam passage and wiring space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current flows through the blanking aperture array substrate to perform blanking control, then beam deflection control is achieved, but magnetic field is generated causing beam trajectory bending and writing accuracy degradation
Solution Approach 1:
A magnetic shield member made of high magnetic permeability material is introduced as an intermediary between the blanking aperture array substrate and the beam path. This shield member absorbs and redirects the magnetic field generated by the blanking control current, preventing it from bending the beam trajectory while allowing the blanking control function to operate normally
Solution Approach 2:
The harmful magnetic field effect is extracted and separated from the blanking control function. By placing the magnetic shield member, the magnetic field is directed away from the beam path, isolating the harmful effect from the useful function of beam deflection control
2Manufacturing precision
If shield members are added to block magnetic field, then beam trajectory stability is improved, but device complexity increases
Solution Approach 1:
Instead of providing complete 360-degree magnetic shielding, the shield member is strategically positioned only where the magnetic field intersects with the beam path. This localized shielding approach provides the necessary protection against beam trajectory bending while minimizing the amount of shielding material and structural complexity required
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 magnetic field is effectively shielded, minimizing beam deflection and ensuring high accuracy in beam irradiation positions on the sample surface, thereby enhancing the writing precision and adhering to specific beam passage and wiring requirements.
Implementation Method 1
the magnetic field generated by a current which flows through the blanking aperture array substrate causes beam trajectory bending
Implementation Method 2
The use of high magnetic permeability shield members, such as those composed of permalloy, is implemented to absorb and redirect the magnetic field
Implementation Method 3
The blanking aperture array substrate has electrode pairs each for independently deflecting a beam, and an opening for beam passage between each electrode pair. Blanking control is independently performed on a passing electron beam by fixing one of each electrode pair (blanker) to the ground potential and switching the other electrode between the ground potential and other potential.
Data Source
AI summary
In one embodiment, a multi charged particle beam writing apparatus includes a blanking aperture array substrate provided with a plurality of blankers configured to respectively perform blanking deflection on a plurality of charged particle beams included in a multi-beam, and a first shield member which is disposed downstream of the blanking aperture array substrate with respect to a travel direction of the multi-beam, has a cylindrical part in which the multi-beam passes through, and is composed of a high magnetic permeability material.