Low Force Probe Card Interconnects Using Foam Mediator
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Solution Overview
Problem
Conventional probe card assemblies face limitations such as high force exertion on substrates, poor planarity, labor-intensive installation, and unreliable electrical contacts, making them unsuitable for high-density applications.
Innovation Solution
A probe card assembly with a substrate support structure that includes alignment members, stiffener members, and a proximity detection mechanism, using substrate through-hole or bonded attachment assemblies to securely position the substrate with minimal force, and wedge bonding for interconnects, allowing precise alignment and reduced stress on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pogo pins with spring components are used to provide electrical connections, then electrical contact reliability is improved, but high aggregate force is exerted on the substrate causing deflection, misalignment or cracking
Solution Approach 1:
The patent removes the spring component from the interconnect structure, extracting the harmful elastic force-generating element while retaining the electrical connection function through rigid or flexible printed circuit board traces that do not exert excessive force on the substrate
Solution Approach 2:
The patent introduces a foam layer as an intermediary between the substrate and the interconnect structure, which provides compliance and electrical connection without requiring high contact forces, thereby mediating between the need for reliable electrical contact and the need to minimize substrate stress
2Reliability
If pogo pins are used in high density applications, then electrical connection capability is improved, but installation becomes very labor intensive and coplanarity deteriorates
Solution Approach 1:
The patent replaces the mechanical spring-based pogo pin system with a printed circuit board-based interconnect system where electrical connections are formed through conductive traces on rigid or flexible PCBs, eliminating the need for individual mechanical assembly of spring components and significantly reducing labor intensity
3Force
If solder bumps are used to provide electrical connections, then spring component-related problems are avoided, but reliable electrical contact cannot be ensured and repairability is poor
Solution Approach 1:
The patent introduces a foam layer as an intermediary that provides the necessary compliance and electrical connection reliability without requiring solder bumps, allowing for reliable low-force connections that maintain contact integrity while enabling repairability through the modular foam insert design
4Reliability
If conventional probe card assemblies are used, then electrical connection is achieved, but substrate deflection and cracking occur due to high force exertion
Solution Approach 1:
The patent removes the spring component from the interconnect structure, extracting the harmful elastic force-generating element while retaining the electrical connection function through rigid or flexible printed circuit board traces that do not exert excessive force on the substrate
Solution Approach 2:
The patent introduces a foam layer as an intermediary between the substrate and the interconnect structure, which provides compliance and electrical connection without requiring high contact forces, thereby mediating between the need for reliable electrical contact and the need to minimize substrate stress
Data Source
AI summary
A probe test card assembly for testing of a device under test includes a printed circuit board, a substrate and a substrate support structure. The substrate support structure holds the substrate in position with respect to the printed circuit board. The substrate support structure may include one or more alignment members, one or more hard stop members and/or a support plate attached to the printed circuit board for positioning the substrate with respect to the printed circuit board. The one or more alignment members may extend through the printed circuit board and be connected to the one or more printed circuit board stiffener members. The probe test card assembly may also employ a proximity detection feature to indicate when the substrate is in a particular position with respect to the printed circuit board.