Compliant Pedestal for IC Testing Profile Conformance

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Solution Overview

Problem

Conventional device testers deform IC devices due to undue pressure, especially on curved substrates, leading to uneven and flattened surfaces during testing, which is exacerbated by the assumption that devices are flat, causing permanent deformation in thinner substrates used in portable devices.

Innovation Solution

A thermal control unit with a test socket assembly that conforms to the IC device's profile, featuring a pedestal assembly with a heat-conductive pedestal, temperature-control fluid circulation, and a controllable force distributor to maintain set-point temperature and distribute forces evenly, preventing deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional device testers with flat pedestals and pushers are used, then testing functionality is achieved, but undue pressure is exerted on curved DUTs causing deformation and flattening of the device surface

Engineering Contradiction:
Improvetesting functionalityVSAvoiddevice surface profile
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The pedestal and substrate pusher are designed with curved surfaces that match the natural curvature of the DUT. This allows the testing equipment to conform to the device's bowed profile without exerting undue localized pressure, thereby preventing deformation while maintaining testing functionality.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the pedestal and pusher from flat to curved profiles. This parameter modification enables the equipment to adapt to the curved DUT surface, distributing pressure evenly and preventing the flattening effect that occurs with conventional flat components.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If flat pedestals and substrate pushers contact only specific areas, then testing is simplified, but uneven pressure is exerted causing flattened and uneven device surfaces after testing

Engineering Contradiction:
Improvetesting setup simplicityVSAvoiddevice surface uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The pedestal and substrate pusher are designed with varying local properties - specifically, curved surfaces with different radii of curvature in different regions. This allows each local area to contact the DUT appropriately, distributing pressure evenly across the curved surface and preventing localized flattening while maintaining testing simplicity.

Inventive Principle:
Principle #3Local quality

3Device complexity

If conventional testers assume flat device profiles, then device tester design is simplified, but curved substrates experience undue pressure especially on thinner substrates used in portable devices

Engineering Contradiction:
Improvetester design simplicityVSAvoidpressure on substrate
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The pedestal and substrate pusher incorporate curved surfaces matching the DUT's natural profile. This curvature design allows the components to follow the bowed shape of thin substrates without concentrating force on specific areas, thereby reducing undue pressure while maintaining reasonable design complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The geometric parameters of the contacting surfaces are changed from flat to curved, with specific radius values selected to match typical DUT profiles. This parameter change enables the tester to accommodate thin substrates in portable devices without exerting excessive localized pressure.

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 minimizes deformation of IC devices during testing, ensuring accurate functionality and reducing losses due to physical damage or poor contact alignment in subsequent assembly, particularly effective for thinner substrates used in compact portable devices.

Implementation Method 1

a heat-conductive pedestal, a temperature-control fluid circulation block

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

temperature-control fluid circulation block

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentUS9229049B2Systems and methods for conforming test tooling to integrated circuit device profiles with compliant pedestals
Publication Date: 2016.01.05 ESSAI INC

AI summary

A test socket assembly, useful in association with a thermal control unit used to maintain a set point temperature on an IC device under test, has at least one compliant pedestal is configured to facilitate the testing of integrated circuits where the device under test comprises a substrate having multiple IC chips with different heights and testing requirements.