RF Absorptive IC Test Contactor for Reflection Suppression

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Solution Overview

Problem

Existing contactor designs for integrated circuit testing fail to maintain signal integrity due to RF reflections, which degrade test signal quality.

Innovation Solution

A contactor with a radio frequency absorptive material, such as elastomers, polymers, or foam rubber, is used to absorb a significant portion of test signal energy between DC and 110 GHz, and the contactor is designed with varying hole sizes to control impedance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional contactor designs are used, then the structure is simple and easy to manufacture, but RF reflections occur that degrade signal integrity

Engineering Contradiction:

Improvesignal integrityVSAvoidcontactor structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies RF absorptive material to the contactor body to convert harmful RF reflections into beneficial signal attenuation. The absorptive material absorbs reflected RF energy, transforming the harmful reflection effect into a beneficial signal conditioning effect that improves signal integrity while maintaining test accuracy.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The contactor is constructed as a composite structure combining conductive material (for electrical connectivity) with RF absorptive material (for signal integrity). This multi-material approach allows the contactor to simultaneously provide electrical conduction and RF reflection suppression, resolving the contradiction between structural simplicity and signal quality.

Inventive Principle:

Principle #40Composite materials

2Reliability

If RF absorptive material is added to the contactor, then signal integrity is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvetest signal qualityVSAvoidcontactor fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent specifies using foam rubber or porous RF absorptive material that can be directly molded or inserted into the contactor body. This porous structure allows for simple manufacturing processes such as molding or snap-fitting, avoiding complex assembly steps while effectively absorbing RF reflections across the required frequency range.

Inventive Principle:

Principle #31Porous materials

3Object-affected harmful factors

If the contactor body is made larger to accommodate RF absorptive material, then RF reflection is reduced, but the contactor size increases

Engineering Contradiction:

ImproveRF reflectionVSAvoidcontactor footprint

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The RF absorptive material is applied locally to specific surfaces of the contactor body where RF reflections occur, rather than requiring the entire contactor to be enlarged. This localized treatment approach effectively reduces RF reflections while maintaining a compact overall contactor size suitable for probe card integration.

Inventive Principle:

Principle #3Local quality

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 RF reflections, maintaining signal integrity and improving test signal quality for integrated circuit testing.

Implementation Method 1

the radio frequency absorptive material absorbs a significant portion of the test signal energy in a frequency band of between about DC and about 110 GHz

Methodology Applied

Scientific EffectRF absorption: Absorption (EM radiation)

Data Source

PatentEP4374176B1Reflective and interference controlled absorptive contactor and method of forming said contactor

Publication Date: 2026.04.15 XCERRA CORP

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AI summary

An apparatus (100) including a contactor (102) having a hole (106) and including a radio frequency absorptive material (108) and a probe (104) inserted in the hole (106) to couple a test signal to a device under test, such as an integrated circuit (206), is disclosed. A test system for testing integrated circuits (206) including a contactor (102) including a radio frequency absorptive material (108) is disclosed. A method for making the contactor (102) is also disclosed, where the radio frequency absorptive material (108) is formed by 3D printing, moulding, coating or micro-machining.