Diamond Core Test Probes for IC Contact Reliability

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Solution Overview

Problem

Current test socketing solutions for packaged IC devices suffer from deviation and inconsistency in penetration capability and electrical continuity due to wear and tear, leading to invalid test failures, high retest rates, and increased downtime, primarily caused by contact probe tip deformation, plated layer peel-off, and loss of compliant force over repeated testing cycles.

Innovation Solution

A test probe assembly featuring probes with a hard core material like diamond and hardened surfaces, supported by a pad and PCB/interposer, maintains reliable electrical contact through compliant force, reducing wear and tear and enhancing long-term functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact probes are made from conductive metals and metallic alloys with plated conductive layers, then electrical continuity is achieved, but contact probe tip deformation and plated layer peel-off occur after repeated testing

Engineering Contradiction:

Improveelectrical continuityVSAvoidcontact probe tip durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The contact probe employs a composite structure combining a hard core material (diamond or cubic boron nitride) with a conductive coating layer. This composite design provides both the mechanical hardness needed to resist deformation and the electrical conductivity required for continuous contact, resolving the contradiction between durability and electrical continuity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters of the contact probe by using ultra-hard materials (diamond with hardness 1000-1500 HV or cubic boron nitride with hardness 900-1200 HV) instead of traditional metals. This parameter change fundamentally improves resistance to deformation and wear while maintaining electrical conductivity through the conductive coating.

Inventive Principle:

Principle #35Parameter changes

2Force

If spring or elastic elements are used to provide compliant force, then penetration capability is achieved, but loss of compliant force occurs after repeated testing

Engineering Contradiction:

Improvecompliant forceVSAvoidtest tooling life cycle

Core Design Contradiction:

ForceVSDuration of action of stationary object

Solution Approach 1:

The invention replaces the mechanical spring/elastic element system with a compliant force mechanism integrated into the probe structure itself. The hard core material provides inherent compliance through its elastic deformation characteristics, eliminating the need for separate spring elements that suffer from fatigue and loss of force over time.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If contact pitch is reduced to 0.2 mm or less for smaller IC devices, then adaptability to miniaturized devices is improved, but penetration capability and contact reliability deteriorate

Engineering Contradiction:

Improvecompatibility with miniaturized IC devicesVSAvoidcontact capability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The invention changes the material hardness parameter to ultra-high levels (diamond or cubic boron nitride) which enables the contact probe to maintain adequate penetration capability even at reduced contact pitches of 0.2 mm or less. The extreme hardness compensates for the reduced leverage and contact area available at smaller pitch dimensions.

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

The solution ensures extended reliable testing of IC devices with reduced downtime and contact probe degradation, maintaining consistent contact capability even after repeated cycles, addressing the issues of wear and tear and contact pitch size reduction.

Implementation Method 1

the tips of these contact probes of the test tooling have been impacted continually by the solder balls of the IC devices under test. As a result, the contact probe tips are often subjected to contact point deformation

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The plurality of probes is configured to repeatedly maintain reliable electrical contact with a corresponding plurality of DUT contacts when under a compliant force

Methodology Applied

Scientific EffectMechanical force: Mechanical Force

Data Source

PatentUS10094853B2Systems and methods for reliable integrated circuit device test tooling

Publication Date: 2018.10.09 ESSAI INC

AI summary

In one embodiment of the present invention, a test probe assembly for testing packaged integrated circuit (IC) devices includes a plurality of probes, a pad and a PCB/interposer. The plurality of probes is configured to repeatedly maintain reliable electrical contact with a corresponding plurality of DUT contacts when under a compliant force. The pad provides mechanical support and/or electric coupling for the plurality of probes. In turn, the PCB/interposer supports the pad. In some embodiments, the plurality of probes includes a hard core material such as diamond. In other embodiments, the surface of the probes is hardened.