Decoupled Core-Shell Electrical Test Probes for High-Frequency Impedance Matching

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Solution Overview

Problem

Vertical probes for testing electrical devices face a conflict between electrical and mechanical design requirements at higher frequencies, leading to limited deflection range and susceptibility to damage, as existing solutions fail to decouple these design aspects effectively.

Innovation Solution

The implementation of a core-shell structure where the core provides mechanical resilience and the shell serves as the primary electrical current path, allowing for impedance matching and improved electrical testing performance, while decoupling electrical and mechanical design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the probe length is increased to improve mechanical resilience and reduce particle damage susceptibility, then mechanical properties improve, but electrical performance degrades at higher frequencies

Engineering Contradiction:
Improvemechanical resilienceVSAvoidelectrical testing performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The probe is segmented into two distinct functional components: a core structure optimized for mechanical resilience and a shell structure optimized for electrical performance. This segmentation allows each component to be independently optimized for its primary function while working together as an integrated system, resolving the contradiction between mechanical strength and electrical reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The probe employs a composite core-shell structure where the core and shell are made of different materials with complementary properties. The core provides mechanical support and resilience, while the shell provides optimal electrical conductivity and impedance characteristics. This composite approach enables simultaneous achievement of both mechanical resilience and high-frequency electrical performance.

Inventive Principle:
Principle #40Composite materials

2Length of moving object

If the probe length is increased to provide desired mechanical properties, then mechanical deflection range improves, but electrical bandwidth is limited

Engineering Contradiction:
Improveprobe lengthVSAvoidelectrical bandwidth
Core Design Contradiction:
Length of moving objectVSSpeed

Solution Approach 1:

By separating the probe into core and shell components with distinct optimization goals, the design allows long probe lengths for mechanical benefits without compromising electrical bandwidth. The shell is specifically engineered to maintain optimal electrical characteristics despite the increased length.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shell structure's electrical parameters (conductivity, impedance, geometry) are specifically optimized to compensate for the effects of increased length, maintaining high bandwidth performance. Mechanical parameters of the core are simultaneously optimized for the desired deflection range.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the probe is designed for short length to maintain electrical performance, then electrical reliability improves, but mechanical susceptibility to damage increases

Engineering Contradiction:
Improveelectrical testing performanceVSAvoidsusceptibility to particle damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The segmentation into core and shell allows the core to be designed as a robust, longer structure that provides mechanical protection and resilience, while the shell maintains optimal electrical characteristics. This resolves the contradiction by assigning different length and structural optimizations to different components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The composite structure enables the core to provide enhanced mechanical protection against particle damage while the shell ensures electrical reliability. The synergistic combination of materials and structures allows both contradictory requirements to be satisfied simultaneously.

Inventive Principle:
Principle #40Composite materials

4Ease of manufacture

If the probe uses a single integrated structure, then manufacturing is simpler, but electrical and mechanical design requirements cannot be simultaneously satisfied

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddesign flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

While the probe is structurally segmented into core and shell components, the manufacturing process is designed to minimize complexity. The components can be manufactured separately with optimized processes for each function, then assembled using standardized procedures. This segmentation actually enhances design flexibility while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The core-shell design creates a universal platform that can satisfy both electrical and mechanical design requirements simultaneously. The modular nature allows the same basic structure to be adapted for different applications by adjusting parameters, enhancing versatility without proportionally increasing manufacturing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3807656B1Electrical test probes having decoupled electrical and mechanical design
Publication Date: 2024.08.07 FORMFACTOR INC
  • EP3807656B1 patent drawingFigure 1A~1B
  • EP3807656B1 patent drawingFigure 2
  • EP3807656B1 patent drawingFigure 3

AI summary

Probes for testing electrical circuits having decoupled electrical and mechanical design are provided. For example, a mechanically resilient core can be surrounded by an electrically conductive shell, In this way, electrical parameters of the probes are determined by the shells and mechanical parameters of the probes are determined by the cores, An important application of this approach is to provide impedance matched transmission line probes.