Compliant Organic Substrate Assembly for Wafer Test Probes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rigid probe devices face challenges in achieving adequate contact with non-uniform and decreasingly sized solder balls on microcircuits due to their lack of deformation, leading to inadequate electrical contact and inaccurate wafer testing results.
Innovation Solution
A compliant organic substrate assembly for rigid probes is introduced, featuring a laminate structure with a compliant layer made of an elastomer that allows independent deflection of the laminate structures, enabling the rigid probes to match the contour of the solder bump array and maintain contact with varying solder ball heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rigid probes are used to convey more power to microelectronic devices, then power transmission capability is improved, but the ability to accommodate non-uniform solder ball shapes and varying heights deteriorates
Solution Approach 1:
The rigid probe device is segmented into a rigid probe array substrate and a separate compliant layer. The rigid substrate maintains structural integrity and power transmission, while the compliant layer independently accommodates solder ball variations, resolving the contradiction between rigidity for power and compliance for contact reliability.
Solution Approach 2:
The device uses a composite structure combining rigid materials (for the probe array substrate) with compliant materials (for the compliant layer). This composite approach allows simultaneous achievement of high power transmission capability through the rigid portion and reliable electrical contact through the compliant portion that adapts to solder ball variations.
2Ease of manufacture
If rigid probes are used to reduce manufacturing cost via photolithography, then manufacturing cost is reduced, but the ability to deform and match solder ball contours deteriorates
Solution Approach 1:
The device separates the rigid probe array (manufactured via photolithography) from the compliant layer. This segmentation allows the rigid portion to be cost-effectively manufactured while the compliant portion provides the necessary adaptability to solder ball variations, resolving the contradiction between manufacturing ease and adaptability.
Solution Approach 2:
The compliant layer is positioned specifically at the probe tips where contact with solder balls occurs, providing local adaptability only where needed. The bulk of the structure remains rigid for cost-effective manufacturing, resolving the contradiction between overall manufacturing ease and local adaptability requirements.
3Adaptability or versatility
If compliant vertical probes are used to accommodate solder ball variations, then adaptability to non-uniform solder balls is improved, but power transmission capability deteriorates
Solution Approach 1:
The device segments the power transmission function (handled by the rigid probe array substrate) from the adaptation function (handled by the compliant layer). This allows high power transmission capability to be maintained through the rigid structure while the compliant layer provides necessary adaptability to solder ball variations.
Solution Approach 2:
The composite structure combines rigid materials for power transmission with compliant materials for adaptation. The rigid substrate ensures high power transmission capability while the compliant layer ensures adaptability to solder ball variations, resolving the contradiction between these two opposing requirements.
4Adaptability or versatility
If individually flexing needles are used for each probe, then adaptability to solder ball variations is improved, but device complexity increases
Solution Approach 1:
The device segments the adaptation function into a separate compliant layer that is simpler in structure than individually flexing needles for each probe. This compliant layer provides collective adaptability to all probes simultaneously, reducing device complexity while maintaining adaptability to solder ball variations.
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 compliant layer ensures consistent and accurate electrical contact across all solder bumps, even those with concave shapes and varying heights, enhancing the reliability of wafer testing by allowing the probes to deform and maintain contact without altering the load required for rigid probe devices.
Implementation Method 1
A compliant layer between the first laminate structure and the second laminate structure includes an elastomer that exhibits compliance within a limited range of movement
Data Source
AI summary
A wafer test device and methods of assembling a wafer test device involve a first laminate structure, and a second laminate structure arranged to interface with a microcircuit of the wafer. The wafer test device includes a compliant layer between the first laminate structure and the second laminate structure. The compliant layer includes an elastomer that exhibits compliance within a limited range of movement.