Elastomeric Contact Support for IC Test Socket Wear

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Solution Overview

Problem

Traditional test sockets experience contact wear and deformation over repeated testing cycles, leading to inconsistent connections and incorrect categorization of 'good' integrated circuit devices as 'bad' due to worn or deformed contacts.

Innovation Solution

The use of an elastic contact support system that maintains proper alignment and applies a supporting force to cantilevered contact fingers, utilizing an elastomeric strip with conductive channels and a deformable metal material like beryllium copper, which compresses to ensure consistent electrical contact and prevent plastic deformation, thereby extending the socket's lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional rigid contact fingers are used in test sockets, then initial electrical contact is established, but contact wear and deformation occur over repeated testing cycles leading to inconsistent connections

Engineering Contradiction:

Improveelectrical contact consistencyVSAvoidsocket lifespan

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The contact fingers are changed from rigid material to elastomeric material, fundamentally changing the physical parameter of flexibility. This allows the contacts to deform elastically during insertion and testing, then return to original position, preventing permanent deformation and wear accumulation over thousands of test cycles.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The contact fingers are designed with dynamic characteristics through the elastomeric material properties, allowing them to flex and adapt during device insertion and testing. The dynamic elasticity enables the contacts to absorb mechanical stress and maintain consistent electrical connection without rigid wear.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If cantilevered contact fingers are used to accommodate device insertion, then device insertion is facilitated, but plastic deformation occurs leading to misalignment

Engineering Contradiction:

Improvedevice insertionVSAvoidcontact alignment

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The contact finger material parameter is changed from rigid metal to elastomeric material with appropriate durometer hardness. This allows the cantilevered structure to flex during insertion without permanent deformation, maintaining precise alignment after the device is seated.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The elastomeric material provides inherent cushioning and shock absorption before the device is fully inserted. This pre-cushioning prevents impact forces from causing misalignment or damage to the contact fingers during the insertion process.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If repeated testing cycles are performed, then manufacturing productivity increases, but contact wear causes false failure categorization

Engineering Contradiction:

Improvetesting cycles per socketVSAvoidtest accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The contact material is changed to elastomeric with high fatigue resistance properties, enabling the socket to withstand hundreds of thousands of insertion and testing cycles without degradation. This maintains both high productivity through repeated use and reliability through consistent electrical contact throughout the socket's operational life.

Inventive Principle:

Principle #35Parameter changes

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 significantly increases the number of testing cycles before socket failure, maintaining reliable electrical contact and preventing electrostatic discharge, allowing for up to 200,000 test cycles or more without compromising the integrity of the integrated circuit.

Implementation Method 1

an elastomeric strip with conductive channels and a deformable metal material like beryllium copper, which compresses to ensure consistent electrical contact and prevent plastic deformation

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

an elastomeric strip with conductive channels

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

preventing electrostatic discharge

Methodology Applied

Scientific EffectElectrostatic discharge resistance: Electrostatic Discharge

Data Source

PatentUS7686621B2Integrated circuit test socket having elastic contact support and methods for use therewith

Publication Date: 2010.03.30 NXP USA INC

AI summary

A socket can be used for testing an integrated circuit package having a plurality of rows of leads. The socket includes a base that is aligned with a circuit board having a plurality of contact pads. A plurality of rows of contact fingers are electrically coupled to the plurality of contact pads, each of the plurality of rows of contact fingers for engaging a corresponding one of the plurality of rows of leads in response to a retention force applied to the integrated circuit package. Each of the contact finger has a cantilevered end that is supported by a supporting force generated by an elastic contact in response to the retention force.