Probe Card Through-Hole Coaxial Routing for Signal Integrity
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Solution Overview
Problem
Existing probe cards face challenges in impedance matching and noise resistance during high-frequency signal testing, affecting test accuracy and yield rates in semiconductor products.
Innovation Solution
A probe card design incorporating a circuit substrate, space transformer, and coaxial cable with a flush end surface, where the coaxial cable is directly inserted through a through hole in the substrate, enhancing impedance continuity and noise resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional wire connecting methods are used in probe cards, then the structure is easier to manufacture, but the impedance matching and noise resistance deteriorate during high-frequency signal testing
Solution Approach 1:
The patent extracts and removes the traditional wire connecting structure from the probe card design. Instead of using separate wires to connect signal paths, the invention directly integrates the coaxial cable conducting part into the through hole, eliminating the intermediate wire connection layer and its associated impedance discontinuities.
Solution Approach 2:
The patent merges the coaxial cable conducting part directly with the through hole structure in the circuit substrate. The conducting part is inserted into and becomes an integral part of the through hole pathway, combining the cable integration function with the substrate routing function into a single unified structure that maintains impedance continuity.
2Object-affected harmful factors
If traditional wire connecting methods are used in probe cards, then the manufacturing process is simpler, but the ability to resist noise deteriorates during high-frequency signal testing
Solution Approach 1:
The patent removes the vulnerable wire connecting structure that acts as an antenna for noise pickup. By extracting this intermediate connection layer and replacing it with a direct coaxial cable integration into the through hole, the design eliminates the exposed wire segments that would otherwise capture electromagnetic interference during high-frequency testing.
Solution Approach 2:
The coaxial cable's conducting part serves as an intermediary structure that directly bridges the connection between the probe setting surface and the circuit substrate. This intermediary replaces the traditional wire-to-wire connections with a controlled impedance pathway that shields the signal from external noise while maintaining electrical continuity.
3Reliability
If the conducting part of coaxial cable extends out from probe setting surface, then insertion into through hole is easier, but impedance continuity deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-processing the conducting part of the coaxial cable before insertion. The end of the conducting part is pre-shaped and positioned to match the dimensions and geometry of the through hole, ensuring that when inserted, it achieves flush alignment with the probe setting surface without extending beyond it, thereby maintaining impedance continuity.
4Measurement precision
If signal wire impedance matching is improved, then high-frequency test accuracy is improved, but the probe card structure becomes more complex
Solution Approach 1:
The patent extracts the complex signal wire routing structure from the probe card design. By removing the traditional layered wire connections and replacing them with a direct coaxial cable integration into the through hole, the invention simplifies the overall signal path structure while achieving superior impedance matching, thereby improving high-frequency test accuracy without the complexity of multiple wire layers and connections.
Data Source
AI summary
The disclosure provides a probe card comprising a circuit substrate, a space transformer, and a first coaxial cable. The circuit substrate has a first surface and a second surface, wherein a through hole penetrates the circuit substrate from the first surface to the second surface. The space transformer is arranged on the second surface corresponding to the through hole and has a probe setting surface opposite to the second surface. The first coaxial cable has a first conducting part and a first insulating part, wherein the first coaxial cable is inserted into the through hole, and a first end surface of the first conducting part is flush with the probe setting surface.