Kelvin Contacts for Microcircuit Tester Alignment
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Solution Overview
Problem
Current microcircuit test equipment faces challenges in making accurate, non-destructive electrical connections due to the small size and close spacing of microcircuit contacts, leading to incorrect connections, wear, and contamination issues, which result in false defect identification and increased costs.
Innovation Solution
The development of a device with laterally oriented electrically insulating housing and compressible/deflectable force contacts, along with laterally arranged sense contacts that surround or slide with force contacts, to ensure precise alignment and minimize wear, allowing for temporary mechanical and electrical connections without damaging the microcircuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional test contacts are used with closely spaced microcircuit contacts, then testing capability is achieved, but alignment accuracy deteriorates leading to incorrect connections
Solution Approach 1:
The test contact structure is segmented into separate force contact and sense contact components, each independently positioned and functioned. This segmentation allows precise alignment of each contact type with the corresponding microcircuit contacts, improving measurement accuracy while managing structural complexity through modular design
Solution Approach 2:
The force contact acts as an intermediary element that applies controlled force to establish reliable electrical connection between the test equipment and the microcircuit. This intermediary mechanism ensures accurate positioning and stable contact without requiring direct complex alignment between all testing components and the microcircuit terminals
2Productivity
If automated testing at high speed is implemented, then productivity increases, but contact wear accelerates causing contamination
Solution Approach 1:
The harmful wear and contamination effects are extracted and isolated to the force contact elements, which are designed to be replaceable. The sense contacts, which are critical for accurate measurement, are protected from direct wear by being positioned separately and not bearing the mechanical load, thus maintaining connection reliability during high-speed automated testing
Solution Approach 2:
The force contacts are designed with compliant or cushioning characteristics that absorb mechanical stress and wear before it can affect the sense contacts or the microcircuit terminals. This beforehand cushioning protects the critical measurement pathways from contamination and damage during high-speed operation
3Ease of manufacture
If inexpensive tester contacts are used, then cost decreases, but contact durability deteriorates requiring frequent replacement
Solution Approach 1:
The force contacts are designed as inexpensive, replaceable components that can be easily manufactured and swapped out. Since they bear the mechanical wear, their limited lifespan is acceptable as they can be quickly replaced without affecting the overall system. The sense contacts, being more critical for measurement accuracy, are designed for longer service life
Solution Approach 2:
The force contact elements are designed to be discarded after a certain period of high-wear operation and replaced with new contacts. This approach allows the use of simpler, cheaper materials for the force contacts while maintaining system reliability through periodic replacement, rather than requiring expensive, highly durable materials for all contact elements
4Measurement precision
If conventional single contact per terminal is used, then device complexity is minimized, but measurement precision deteriorates due to inability to perform Kelvin testing
Solution Approach 1:
The contact array is segmented into separate force contacts and sense contacts, with each terminal having both types of contacts. This segmentation enables Kelvin testing by providing dedicated current-carrying paths (force contacts) and voltage-sensing paths (sense contacts), significantly improving resistance measurement accuracy while organizing the complexity into a systematic structure
Solution Approach 2:
The contact array structure is designed to support both conventional single-ended testing and Kelvin differential testing modes. Each terminal pair has both force and sense contacts available, allowing the same physical structure to perform multiple measurement functions, thus achieving high measurement precision without requiring separate dedicated contact arrays for different test types
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 enables accurate and reliable testing of microcircuits by preventing misalignment and wear, reducing false defect identification and maintenance costs, while maintaining the integrity of the microcircuits and test equipment.
Implementation Method 1
a plurality of electrically conductive force contacts extending through longitudinal holes in the housing toward the device under test and being compressible/deflectable through the holes in the housing
Implementation Method 2
a plurality of electrically conductive sense contacts, each sense contact in the plurality being laterally arranged to correspond to exactly one force contact and exactly one terminal
Implementation Method 3
Each sense contact in the plurality includes a fixed portion, a free portion extending hingedly away from the housing, and a hinged portion connecting the fixed portion and the free portion
Data Source
AI summary
Terminals (2, 502) of a device under test (DUT) are connected to corresponding contact pads or leads by a series of electrically conductive contacts. Each terminal testing connects with both a “force” contact and a “sense” contact. In one embodiment, the sense contact (770) partially or completely laterally surrounds the force contact (700). In order to increase the contact surface, the force contact, in a spring pin (700) configuration contacts the device under test terminal at that portion of the lead which is curved or angled, rather than orthogonal to the pin.