Coaxial Cable Probe Card for High-Speed Signal Integrity
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Solution Overview
Problem
Current electrical test systems for high-speed wafer-level semiconductor chip testing are limited to about 500 MHz due to signal loss inherent in zero input force (ZIF) connectors used in probe cards, which are not adapted for parallel testing and result in significant signal attenuation.
Innovation Solution
The system employs a coaxial cable bundle to connect a performance board to a probe card, utilizing coaxial cables with signal and ground lines to minimize noise and signal loss, allowing for high-speed parallel testing of semiconductor chips by replacing the conventional ZIF connector with coaxial cable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a ZIF connector is used to connect the performance board to the probe card, then the probe card can be easily connected and disconnected, but significant signal loss occurs at high frequencies
Solution Approach 1:
The patent introduces a coaxial cable as an intermediary component between the performance board and the probe card. This coaxial cable serves as a dedicated signal transmission medium that replaces the ZIF connector's signal path, providing both mechanical connection and electrical signal transmission functions. The coaxial cable acts as a mediator that maintains signal integrity at high frequencies while still allowing for easy connection and disconnection operations.
2Device complexity
If a ZIF connector is used in the probe card, then the structure can be simplified, but signal attenuation increases substantially at frequencies above 500 MHz
Solution Approach 1:
The patent segments the connection system into distinct functional components: the performance board with its ZIF connector for mechanical attachment, the coaxial cable for signal transmission, and the probe card with its test probes. This segmentation allows each component to be optimized for its specific function - the ZIF connector provides easy mechanical connection, while the coaxial cable handles high-frequency signal transmission with minimal attenuation. The separation of these functions resolves the contradiction between structural simplicity and signal integrity.
3Ease of manufacture
If conventional probe card structure with ZIF connector is used, then manufacturing is easier, but high-speed parallel testing beyond 500 MHz is not achievable
Solution Approach 1:
The coaxial cable serves as an intermediary that enables high-speed signal transmission between the performance board and probe card. By introducing this dedicated signal transmission medium, the system achieves super-GHz testing capabilities while maintaining the ease of manufacturing the individual components. The coaxial cable acts as a bridge that allows high-frequency signals to pass through without the attenuation problems of the ZIF connector, thus enabling high-speed parallel testing without complicating the manufacturing process.
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 configuration enables signal loss of −1 dB or less even at high speeds (2 GHz), facilitating super-GHz high-speed parallel testing of semiconductor chips with reduced attenuation and a simplified probe card structure.
Implementation Method 1
The coaxial cables respectively electrically connect the first coaxial cable connection portions of the performance board to the second coaxial cable connection portions of the probe card
Data Source
AI summary
An electrical test system includes a test head, a performance board, a probe card and coaxial cables. The performance board includes a first side and an opposite second side, where the first side of the performance board is electrically connected to the test head and the second side of the performance board includes first coaxial cable connection portions. The probe card includes a first side and an opposite second side, where the first side of the probe card includes second coaxial cable connection portions and the second side includes a wafer test probes. The coaxial cables respectively electrically connect the first coaxial cable connection portions of the performance board to the second coaxial cable connection portions of the probe card.