Rotating Test Contact Minimizes Tin Buildup
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Solution Overview
Problem
Existing test apparatuses face issues with excessive wiping action damaging components and the diminishment of signal integrity due to matte tin buildup during the testing of integrated circuit devices, which affects the longevity and effectiveness of the test sockets and load boards.
Innovation Solution
A contact with multiple ridges and an arcuate edge is designed to minimize tin buildup by rotating and sequentially engaging with the lead or pad of the device under test, mounted in an elastomeric fashion, allowing the arcuate edge to roll across the metallic trace and reducing abrasion and tin accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wiping action is increased to improve connection quality, then connection quality is improved, but component damage increases and test socket life decreases
Solution Approach 1:
The contact is designed with an arcuate leading edge that rolls across the metallic trace during engagement, converting sliding friction into rolling motion. This curvature geometry minimizes abrasive wiping action while maintaining reliable electrical connection, thereby extending test socket life without sacrificing connection quality
Solution Approach 2:
The contact incorporates spring elements that provide dynamic engagement, allowing the contact to flex and rotate during insertion. This dynamic motion enables the arcuate edge to roll rather than slide across the trace, reducing wear while ensuring consistent electrical contact
2Ease of manufacture
If matte tin is applied to facilitate soldering, then soldering is facilitated, but tin buildup occurs on contacts during testing
Solution Approach 1:
The arcuate leading edge of the contact is designed to roll across the matte tin-coated lead or pad during engagement. This rolling motion minimizes the surface area in continuous contact and reduces the adhesion of soft matte tin material to the contact, preventing buildup that would otherwise diminish signal integrity
Solution Approach 2:
The contact design accepts that matte tin will transfer to some degree during testing, but the rolling engagement minimizes this transfer. The contact structure is designed to withstand a certain amount of tin contamination before replacement is needed, optimizing the balance between manufacturing ease with matte tin and testing durability
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 effectively reduces component wear and maintains signal integrity by controlling tin buildup and minimizing abrasion, thereby extending the lifespan of test sockets and improving testing effectiveness.
Implementation Method 1
The contact is mounted in an elastomeric fashion as part of the test set intermediate the load board and the DUT. Rotation of the contact about the axis when the first end of the contact is engaged by the lead of the DUT is thereby facilitated.
Data Source
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AI summary
A contact for use in a test set which can be mounted to a load board of a tester apparatus: The contact, which serves to electrically connect at least one lead of a device being tested with a corresponding metallic trace on the load board, has a first end defining multiple contact points. As the contact is rotated about an axis generally perpendicular to a plane defined by the contact, successive contact points are sequentially engaged by a lead of the device being tested.