Triaxial Chuck with Elastic Insulation for Leakage Prevention
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Solution Overview
Problem
Existing chucks for low current measurements face issues with leakage currents and triboelectric charges due to poor contact and insulation resistance, especially when using ceramic materials, and suffer from high thermal mass and difficulty in maintaining flatness with metal plates.
Innovation Solution
A chuck design featuring a triaxial construction with perforated conductor films and a porous insulation ceramic, where the conductor films are held by vacuum and connected via soldering, clamping, or laser welding, minimizing thickness and thermal mass while using materials like gold, nickel, and aluminum for chemical compatibility and thermal loadability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic materials like AlN are used for triaxial construction, then insulation resistance is improved, but contact quality with conductive layers deteriorates
Solution Approach 1:
The patent changes the surface properties of the ceramic chuck by applying a specific coating layer (e.g., silicon oxide, silicon nitride, or diamond-like carbon) to the contact surfaces. This coating modification enables reliable electrical contact while preserving the high insulation resistance of the underlying ceramic material, thus resolving the contradiction between insulation performance and contact quality.
2Ease of manufacture
If metal plates are used for triaxial construction, then thermal mass increases, but ease of manufacture improves
Solution Approach 1:
The patent employs a composite structure combining ceramic material (for low thermal mass and high insulation resistance) with thin conductive layers (for electrical conductivity). This composite approach replaces heavy metal plates while maintaining the necessary electrical properties and improving thermal characteristics, thus resolving the contradiction between manufacturability and thermal mass.
3Reliability
If triaxial construction with multiple insulated layers is implemented, then leakage currents are reduced, but device complexity increases
Solution Approach 1:
The patent integrates the triaxial construction (force, guard, and shield electrodes with insulation layers) directly into the chuck body structure itself, rather than adding separate components. This merging of functions reduces the number of discrete parts and simplifies assembly while maintaining the leakage current prevention benefits of triaxial construction.
4Ease of manufacture
If conventional chuck construction is used, then manufacturing is simpler, but triboelectric charge generation occurs
Solution Approach 1:
The patent modifies the material parameters of the chuck surface by applying specialized coatings with optimized dielectric properties and surface characteristics. These coating layers reduce triboelectric charge generation during substrate handling while maintaining manufacturing feasibility, thus resolving the contradiction between manufacturing simplicity and triboelectric charge prevention.
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 design effectively prevents leakage currents and triboelectric charges, maintaining flatness and reducing thermal mass while ensuring chemical compatibility and thermal stability, thus enhancing the accuracy of low current measurements.
Implementation Method 1
the conductor films are held by vacuum
Implementation Method 2
connected via soldering, clamping, or laser welding
Data Source
AI summary
A chuck with triaxial construction comprises a receiving surface for a test substrate and arranged below the receiving surface: an electrically conductive first surface element, an electrically conductive second surface element electrically insulated therefrom, and an electrically conductive third surface element electrically insulated therefrom, and, between the first and the second surface element, a first insulation element and, between the second and the third surface element, a second insulation element. A chuck for very low current measurements which can be used to prevent the occurrence of leakage currents and a triboelectric charge and which is configured favourably in terms of production, is achieved because at least one of the electrically conductive surface elements is mechanically connected to at least one insulation element and has an elasticity that compensates for an expansion difference resulting from differences in different coefficients of expansion between a respective surface element and an adjoining insulation element.