Device Interface Board Cavity Back for High Frequency Signal Integrity
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Solution Overview
Problem
High-performance semiconductor testers face challenges in maintaining signal fidelity due to the difficulty in providing closely matched impedance across numerous signal paths, especially with the increased thickness and complexity of device interface boards (DIBs) required for high-frequency analog signals, which leads to signal degradation and mechanical stress.
Innovation Solution
A DIB printed circuit board with a cavity formed on its back side to reduce thickness, allowing high-frequency connectors and electronic components to be mounted closer to the DUT socket, coupled with a signal via for impedance matching, and an encapsulating structure to maintain signal integrity and structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the DIB thickness is increased to provide structural stability and support more signal layers, then the board can sustain mechanical pressure from increased connectors and pogo pins, but the signal path length increases causing greater signal degradation and reflection for very high frequency analog signals
Solution Approach 1:
The patent introduces a cavity structure that creates a three-dimensional space within the DIB, allowing connectors to be positioned at different vertical levels. This dimensional change enables the board to accommodate thick multi-layer construction for mechanical strength while keeping the signal path length short by routing high-frequency signals through vertical vias into the cavity rather than across the full board thickness.
Solution Approach 2:
The DIB is segmented into distinct regions: a top section for DUT socket, a cavity section for high-frequency connectors, and a bottom section for test head connectors. This segmentation allows each region to be optimized independently - the cavity section can be designed with minimal signal path length while the overall board maintains sufficient thickness for structural support.
2Productivity
If more signal layers are added to accommodate increasing number of signal paths for multisite testing, then the DIB can support more DUT's tested simultaneously, but the board thickness increases requiring additional mechanical support and increasing signal path length
Solution Approach 1:
The cavity structure utilizes the vertical dimension to house high-frequency connectors and signal routing, allowing multiple signal paths to be accommodated through vertical via arrangements rather than requiring proportional increases in horizontal board area or overall thickness.
3Productivity
If the number of connectors and pogo pins is increased to support more signal paths, then more DUT's can be tested simultaneously, but the mechanical pressure on the DIB increases requiring thicker board construction
Solution Approach 1:
The DIB is segmented into distinct regions: a top section for DUT socket, a cavity section for high-frequency connectors, and a bottom section for test head connectors. This segmentation allows each region to be optimized independently - the cavity section can be designed with minimal signal path length while the overall board maintains sufficient thickness for structural support.
4Length of stationary object
If electronic components are placed on the same side as the DUT socket, then the signal path is shorter, but the components are exposed to mechanical stress and may interfere with DUT insertion
Solution Approach 1:
The cavity structure creates a protected three-dimensional space that houses electronic components and high-frequency connectors. This vertical positioning protects components from mechanical stress during DUT insertion while maintaining short signal paths through direct via connections to the DUT socket above.
Data Source
AI summary
In one embodiment, a device interface board is provided which includes a printed circuit board with a DUT interface structure, such as socket, associated with a DUT side of the printed circuit board. A high frequency connector and electronic component are mounted in a cavity formed in a back side of the printed circuit board. A signal via through the printed circuit board couples the high frequency connector and electronic component with the DUT interface structure. An encapsulating structure may be provided, which covers the cavity while allowing a cable to connect to the high frequency connector.