Probe Card Thermal Decoupling via Anisotropic Coupling

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Solution Overview

Problem

The existing probe card assemblies for testing electronic devices face issues due to thermal expansion and contraction, leading to warping and misalignment of substrates, which affects the electrical connections and contact between probes and device terminals.

Innovation Solution

A probe card assembly design featuring a stiffener structure, a wiring substrate, and a frame with non-adjustably fixed coupling mechanisms that are stiff in one direction and flexible in another, allowing for thermal expansion while maintaining contact and alignment of probes with device terminals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple substrates with different materials are coupled together in the probe card assembly, then electrical connections and probe functionality are achieved, but thermal expansion differences cause warping and misalignment

Engineering Contradiction:

Improvesubstrate material diversityVSAvoidsubstrate alignment

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The probe card assembly is divided into separate substrate layers (wiring substrate and probe substrate) that are coupled through intermediate structures. This segmentation allows each substrate to be made of different materials optimized for its specific function while reducing direct thermal expansion conflicts between them.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Intermediate coupling structures are introduced between the wiring substrate and probe substrate to mediate their thermal expansion differences. These intermediaries absorb and accommodate the differential thermal movement, preventing direct warping and misalignment between the substrates.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If rigid coupling mechanisms are used to maintain probe alignment, then electrical connection stability is improved, but thermal expansion is constrained causing stress

Engineering Contradiction:

Improveelectrical connection stabilityVSAvoidthermal stress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Different regions of the coupling mechanisms have different degrees of rigidity. The coupling structures are designed to be rigid in directions that maintain electrical connection stability while being flexible or compliant in directions that accommodate thermal expansion, allowing localized optimization of mechanical properties.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coupling mechanisms are designed with dynamic characteristics that allow them to adapt to thermal changes. The structures can flex or deform in controlled ways during thermal expansion and contraction, maintaining reliable electrical connections while accommodating thermal stress through controlled movement.

Inventive Principle:

Principle #15Dynamics

3Stability of the object's composition

If probe substrates are rigidly fixed to the frame, then structural stability is improved, but thermal expansion causes misalignment with device terminals

Engineering Contradiction:

Improvestructural stabilityVSAvoidprobe terminal alignment

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The mechanical properties of the coupling between probe substrates and the frame are optimized by changing parameters such as the stiffness, flexibility, and compliance characteristics. This allows the coupling to maintain structural stability during normal operation while accommodating thermal expansion to preserve probe terminal alignment with device terminals.

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 design minimizes warping and misalignment, ensuring reliable electrical connections and consistent contact between probes and device terminals during testing, even with thermal changes.

Implementation Method 1

Temperature changes or gradients can thus cause the different substrates to expand or contract different amounts

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

this can cause the wiring substrate 202 and the probe substrate 206 to warp

Methodology Applied

Scientific EffectWarping: Deformation

Data Source

PatentUS7772863B2Mechanical decoupling of a probe card assembly to improve thermal response

Publication Date: 2010.08.10 FORMFACTOR INC

AI summary

A stiffener structure, a wiring substrate, and a frame having a major surface disposed in a stack can be part of a probe card assembly. The wiring substrate can be disposed between the frame and the stiffener structure, and probe substrates can be coupled to the frame by one or more non-adjustably fixed coupling mechanisms. Each of the probe substrates can have probes that are electrically connected through the probe card assembly to an electrical interface on the wiring substrate to a test controller. The non-adjustably fixed coupling mechanisms can be simultaneously stiff in a first direction perpendicular to the major surface and flexible in a second direction generally parallel to the major surface.