Multi-Member Test Probe Structure for Small Pitch IC Interconnects
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Solution Overview
Problem
As silicon bump pitch of integrated circuit (IC) devices scales to smaller dimensions, existing probing solutions face challenges in meeting mechanical and electrical testing requirements, necessitating a more effective and reliable method for contacting and transmitting current to interconnect structures.
Innovation Solution
A multi-member test probe structure with cantilever beams forming a tripod, dipod, or quadpod configuration, where each member is attached to a common node and deflects upon contact to ensure firm electrical connection and robust current carrying capability, accommodating smaller interconnect structures with chamfered tips for better contact and distributed force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single probe structure is used, then the device complexity is low, but the reliability and current carrying capability are insufficient for small pitch IC devices
Solution Approach 1:
The probe structure is divided into multiple members (e.g., three members forming a tripod configuration) that are attached to a common node. Each member independently contacts the interconnect structure, distributing the mechanical and electrical load across multiple contact points. This segmentation increases reliability and current carrying capability while maintaining manageable structural complexity through modular design.
2Productivity
If the bump pitch is scaled down, then the IC device density increases, but the mechanical and electrical requirements for probing become more challenging
Solution Approach 1:
The probe members are designed with specific local characteristics including chamfered tips for optimized contact geometry, tailored flexural rigidity for controlled deflection, and material selection for appropriate electrical conductivity. These localized quality enhancements ensure reliable electrical contact and mechanical stability even when probing densely packed small-pitch interconnect structures.
3Strength
If the probe members are made more rigid, then the structural strength increases, but the ability to accommodate misalignment and ensure firm contact decreases
Solution Approach 1:
The probe members are designed with controlled flexibility that allows them to deflect dynamically upon contact with the interconnect structure. This dynamic behavior enables the members to accommodate misalignment, apply firm contact force, and ensure reliable electrical connection. The flexibility is carefully engineered so that the members remain sufficiently rigid to support mechanical loads while being compliant enough to adapt to contact 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 multi-member test probe structure enables reliable and efficient testing by providing stable, parallel current transmission to IC devices, accommodating smaller pitches and ensuring robustness against mechanical failure, while maintaining precise contact with interconnect structures.
Implementation Method 1
each member is attached to a common node and deflects upon contact to ensure firm electrical connection
Data Source
AI summary
A testing arrangement for testing Integrated Circuit (IC) interconnects is provided. In an example, the testing arrangement includes a substrate, and a first interconnect structure. The first interconnect structure may include a first member having a first end to attach to the substrate and a second end opposite the first end, and a second member having a first end to attach to the substrate and a second end opposite the first end. In some examples, the second end of the first member and the second end of the second member are to contact a second interconnect structure of a IC device under test, and the first end of the first member and the first end of the second member are coupled such that the first member and the second member are to transmit, in parallel, current to the second interconnect structure of the IC device under test.