Micro Kelvin Probe With Anisotropic Conductive Elastomer Interposer
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Solution Overview
Problem
Current micro Kelvin measurement methods face challenges such as high cost, inductance issues, and physical limitations when using pin and formed contact technologies, which introduce errors and are not suitable for small pitches or misalignment in resistance and impedance measurements.
Innovation Solution
The use of anisotropic conductive elastomer (ACE) material with magnetically aligned particles in a micro Kelvin probe assembly, where ACE acts as an interposer between the DUT and PCB contacts, allowing for accurate resistance or impedance measurements by routing separate fine traces and using concentric ring contact pads to maintain contact area consistency despite misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pin and formed contact technologies are used for micro Kelvin measurements, then electrical contact is established, but cost increases and inductance issues arise
Solution Approach 1:
The patent replaces expensive pin and formed contact technologies with a low-cost conductive adhesive material that can be applied as a thin layer. This adhesive material serves as the electrical interposer between PCB contacts and DUT contacts, eliminating the need for costly mechanical contact components while maintaining measurement accuracy.
2Reliability
If pin and formed contact technologies are used for micro Kelvin measurements, then electrical contact is established, but inductance increases reducing bandwidth
Solution Approach 1:
The patent replaces mechanical contact systems (pins and formed contacts) with a conductive adhesive material system. This substitution eliminates the inductance inherent in mechanical contact structures, achieving low-inductance connections that support high-bandwidth measurements while maintaining reliable electrical contact.
3Ease of operation
If conventional contact methods are used, then electrical contact is made, but misalignment causes measurement errors
Solution Approach 1:
The patent merges multiple contact points into a distributed conductive adhesive layer that spans the interface between PCB contacts and DUT contacts. This merged contact structure provides alignment tolerance, as the distributed nature of the adhesive material allows for partial overlap and maintains electrical continuity even when perfect alignment is not achieved.
4Productivity
If interposer resistance is included in voltage measurement, then complete circuit measurement is obtained, but measurement accuracy decreases
Solution Approach 1:
The patent extracts the interposer (conductive adhesive material) from the measurement path by implementing a four-terminal Kelvin measurement configuration. The current terminals pass current through the DUT while the voltage terminals measure voltage directly across the DUT contacts, excluding the interposer resistance from the voltage measurement. This separation allows complete circuit measurement while maintaining high measurement accuracy.
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 solution provides low-cost, high-bandwidth, and low-inductance micro Kelvin measurements, capable of handling smaller pitches and reducing measurement errors by isolating interposer resistances from voltage drop measurements, thus improving measurement accuracy and reliability.
Implementation Method 1
Anisotropic conductive elastomer (ACE) material as an electrical interposer is placed in electrical contact with each of the PCB contacts
Implementation Method 2
The ACE preferably comprises magnetically aligned particles in polymer material
Data Source
AI summary
A micro Kelvin probe assembly and method of accomplishing a micro Kelvin measurement that determines the resistance or impedance of a device under test (DUT) that has two spaced contacts. An ammeter is used to flow current through the DUT, and a voltmeter is used to measure the voltage drop across the DUT. There is a printed circuit board (PCB) carrying two pairs of contacts, with a trace leading to each contact. Anisotropic conductive elastomer (ACE) material as an electrical interposer is placed in electrical contact with each of the PCB contacts. The DUT is placed on the ACE such that each DUT contact is directly opposite one pair of PCB contacts. The ammeter is connected to one trace leading to one contact of each pair of PCB contacts to flow current through the DUT, and the voltmeter is connected to the other trace leading to the other contact of each pair of PCB contacts, so that voltmeter can measure the voltage drop across the DUT without an effect caused by the interposer. In a further embodiment, the PCB contacts are arranged in concentric circles to provide a contact surface area that is relatively constant and more tolerant of misalignment with the DUT contacts.