Universal Spring Contact Pin for IC Test Socket
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Solution Overview
Problem
Existing test sockets and spring contact pins face challenges in maintaining reliable and durable connections with IC devices, especially with surface mount chip packages like LGA, BGA, and SGA, due to issues with tip angle, signal integrity, and alignment, leading to performance degradation over repeated test cycles and varying package types.
Innovation Solution
The design incorporates a spring contact pin with a fixed probe member featuring a conical surface with a large tip angle (75-105 degrees) and a specific length for universal application, along with an improved pin retention mechanism in the test socket that maintains z-axis alignment and reduces air gaps to enhance signal integrity and pointing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a small tip angle is used in the spring contact pin, then the contact pin can be manufactured with simpler geometry, but the signal integrity deteriorates and alignment precision decreases
Solution Approach 1:
The patent changes the geometric parameter of the contact pin tip from a small angle to a large angle (75-105 degrees). This parameter change improves signal integrity and alignment precision while maintaining manufacturability through standardized conical geometry.
2Device complexity
If the spring contact pin is designed for universal application with fixed length, then the device complexity is reduced, but the adaptability to different package types deteriorates
Solution Approach 1:
The patent designs a universal spring contact pin with fixed geometric parameters (length, tip angle 75-105 degrees) that can accommodate multiple surface mount package types (LGA, BGA, SGA) through the socket interface, reducing device complexity while maintaining broad adaptability.
3Ease of operation
If the air gap around the spring contact pin is increased, then the ease of assembly is improved, but the signal integrity deteriorates due to increased signal path length
Solution Approach 1:
The patent employs a composite structure where the spring contact pin is retained within a precisely fitted socket interface. This composite arrangement maintains tight tolerances and minimal air gaps while facilitating assembly, thereby preserving signal integrity.
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 provides robust and reliable connections over numerous test cycles, supports various surface mount packages, and improves high-frequency signal integrity by maintaining alignment and reducing signal path length, thus ensuring effective testing across different chip package types.
Implementation Method 1
a compression spring inside the spring probe barrel
Data Source
AI summary
A universal spring contact pin for use in an IC test Socket includes a depressible probe member at one end and a fixed probe member at the other end. The fixed probe member preferably has a projection length chosen to allow z-axis loading of different surface mount package types within the same test socket. It also can have a relatively large tip angle which preferably terminates at a relatively sharp termination point. Preferably, the tip angle is about 90 degrees and the radius of the termination point of the tip is about 0.001 inches (0.0254 millimeters) or less.