Amorphous-Permalloy Shielding Plate for CD-SEM Weight Reduction
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Solution Overview
Problem
Conventional electromagnetic field shielding plates for semiconductor manufacturing environments are heavy and costly, with insufficient shielding performance against high-frequency electromagnetic fields, leading to disturbances in electron beam scanning and image fidelity in CD-SEM devices.
Innovation Solution
A lightweight electromagnetic field shielding plate is created by stacking a permalloy layer with an Fe—Si—B—Cu—Nb-based amorphous layer, utilizing the attenuation and reflection effects at their interface to enhance shielding performance across a broader frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shielding materials (PC permalloy, μ-metal, silicon steel) with thickness of around 1 mm are used to obtain shielding performance from static magnetic field to alternating magnetic field, then shielding performance is improved, but the weight of the shielding plate becomes heavy (300-400 kg for a device of several thousand mm)
Solution Approach 1:
The patent applies composite materials by stacking multiple layers of different magnetic shielding materials (amorphous magnetic sheets and ferromagnetic sheets) with different thicknesses and orientations. This composite structure achieves superior shielding performance across both low-frequency and high-frequency bands while reducing the overall weight compared to conventional single-material thick plates.
Solution Approach 2:
The shielding plate is segmented into multiple thin layers of amorphous magnetic sheets and ferromagnetic sheets stacked in a specific sequence. Each layer contributes to shielding at different frequency ranges, and the segmented structure allows for optimized material distribution that reduces total weight while maintaining comprehensive shielding effectiveness.
2Reliability
If the thickness of shielding material is increased to improve shielding performance against high-frequency electromagnetic fields, then shielding performance is improved, but the weight and material cost increase significantly
Solution Approach 1:
The patent combines amorphous magnetic sheets with ferromagnetic sheets in a stacked configuration. The amorphous sheets provide excellent high-frequency shielding due to their high resistivity and magnetic properties, while the ferromagnetic sheets enhance low-frequency shielding. This composite approach achieves broad-spectrum shielding performance without requiring excessive thickness of any single material.
Solution Approach 2:
Different regions of the shielding plate use different material compositions and thicknesses optimized for specific frequency ranges. The stacked structure allows local optimization where amorphous sheets dominate for high-frequency protection and ferromagnetic sheets contribute to low-frequency shielding, creating a spatially differentiated shielding strategy that reduces overall material usage.
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 reduces the weight of shielding plates by 30-40% while maintaining high shielding performance against electromagnetic fields, stabilizing material costs and improving image fidelity in semiconductor manufacturing environments.
Implementation Method 1
utilizing the attenuation and reflection effects at their interface to enhance shielding performance
Implementation Method 2
utilizing the attenuation and reflection effects at their interface to enhance shielding performance
Implementation Method 3
an amorphous layer comprising a plate material or a sheet of Fe—Si—B—Cu—Nb-based amorphous
Data Source
AI summary
Provided is an electromagnetic field shielding plate, etc., in which it is possible to reduce weight while achieving high shielding performance from relatively high-frequency electromagnetic fields. The electromagnetic field shielding plate is configured by layering a permalloy layer 3 comprising a plate or sheet of permalloy, and an amorphous layer 1 comprising an Fe—Si—B—Cu—Nb-based amorphous plate or sheet.